#### Sample records for 1h 2h 3h

1. One dimensional 1H, 2H and 3H

Vidal, A. J.; Astrakharchik, G. E.; Vranješ Markić, L.; Boronat, J.

2016-05-01

The ground-state properties of one-dimensional electron-spin-polarized hydrogen 1H, deuterium 2H, and tritium 3H are obtained by means of quantum Monte Carlo methods. The equations of state of the three isotopes are calculated for a wide range of linear densities. The pair correlation function and the static structure factor are obtained and interpreted within the framework of the Luttinger liquid theory. We report the density dependence of the Luttinger parameter and use it to identify different physical regimes: Bogoliubov Bose gas, super-Tonks-Girardeau gas, and quasi-crystal regimes for bosons; repulsive, attractive Fermi gas, and quasi-crystal regimes for fermions. We find that the tritium isotope is the one with the richest behavior. Our results show unambiguously the relevant role of the isotope mass in the properties of this quantum system.

2. Method for determination of {sup 18}O/{sup 16}O and {sup 2}H/{sup 1}H ratios and {sup 3}H (tritium) concentrations of xylem waters and subsurface waters using time-series sampling

SciTech Connect

1999-11-09

This application describes a method for the determination of {sup 18}O/{sup 16}O and {sup 2}H/{sup 1}H ratios and {sup 3}H concentrations of xylem and subsurface waters using time-series sampling, insulating sampling chambers, and combined {sup 18}O/{sup 16}O, {sup 2}H/{sup 1}H and {sup 3}H concentration data on transpired water. The method involves collecting water samples transpired from living plants and correcting the measured isotopic compositions of oxygen ({sup 18}O/{sup 16}O) and hydrogen ({sup 2}H/{sup 1}H and/or {sup 3}H concentrations) to account for evaporative isotopic fractionation in the leafy material of the plant.

3. Method for determination of .sup.18 O/.sup.16 O and .sup.2 H/.sup.1 H ratios and .sup.3 H (tritium) concentrations of xylem waters and subsurface waters using time series sampling

DOEpatents

Smith, Brian; Menchaca, Leticia

1999-01-01

A method for determination of .sup.18 O/.sup.16 O and .sup.2 H/.sup.1 H ratios and .sup.3 H concentrations of xylem and subsurface waters using time series sampling, insulating sampling chambers, and combined .sup.18 O/.sup.16 O, .sup.2 H/.sup.1 H and .sup.3 H concentration data on transpired water. The method involves collecting water samples transpired from living plants and correcting the measured isotopic compositions of oxygen (.sup.18 O/.sup.16 O) and hydrogen (.sup.2 H/.sup.1 H and/or .sup.3 H concentrations) to account for evaporative isotopic fractionation in the leafy material of the plant.

4. Aminosilanes derived from 1H-benzimidazole-2(3H)-thione.

PubMed

Palomo-Molina, Juliana; García-Báez, Efrén V; Contreras, Rosalinda; Pineda-Urbina, Kayim; Ramos-Organillo, Angel

2015-09-01

Two new molecular structures, namely 1,3-bis(trimethylsilyl)-1H-benzimidazole-2(3H)-thione, C13H22N2SSi2, (2), and 1-trimethylsilyl-1H-benzimidazole-2(3H)-thione, C10H14N2SSi, (3), are reported. Both systems were derived from 1H-benzimidazole-2(3H)-thione. Noncovalent C-H···π interactions between the centroid of the benzmidazole system and the SiMe3 groups form helicoidal arrangements in (2). Dimerization of (3) results in the formation of R2(2)(8) rings via N-H···S interactions, along with parallel π-π interactions between imidazole and benzene rings.

5. Amino­silanes derived from 1H-benzimidazole-2(3H)-thione

PubMed Central

Palomo-Molina, Juliana; García-Báez, Efrén V.; Contreras, Rosalinda; Pineda-Urbina, Kayim; Ramos-Organillo, Angel

2015-01-01

Two new mol­ecular structures, namely 1,3-bis­(tri­methyl­silyl)-1H-benzimidazole-2(3H)-thione, C13H22N2SSi2, (2), and 1-tri­methyl­silyl-1H-benzimidazole-2(3H)-thione, C10H14N2SSi, (3), are reported. Both systems were derived from 1H-benzimidazole-2(3H)-thione. Noncovalent C—H⋯π inter­actions between the centroid of the benzmidazole system and the SiMe3 groups form helicoidal arrangements in (2). Dimerization of (3) results in the formation of R 2 2(8) rings via N—H⋯S inter­actions, along with parallel π–π inter­actions between imidazole and benzene rings. PMID:26322611

6. Aminosilanes derived from 1H-benzimidazole-2(3H)-thione

SciTech Connect

Palomo-Molina, Juliana; García-Báez, Efrén V.; Pineda-Urbina, Kayim; Ramos-Organillo, Angel

2015-08-12

In two trimethylsilyl-substituted 1H-benzimidazole-2(3H)-thiones, noncovalent C—H⋯π interactions between the centroid of the benzmidazole system and the SiMe{sub 3} groups form helicoidal arrangements in one, and dimerization results in the formation of R{sub s} {sup 2}(8) rings via N—H⋯S interactions, along with parallel π–π interactions between imidazole and benzene rings, in the second compound. Two new molecular structures, namely 1,3-bis(trimethylsilyl)-1H-benzimidazole-2(3H)-thione, C{sub 13}H{sub 22}N{sub 2}SSi{sub 2}, (2), and 1-trimethylsilyl-1H-benzimidazole-2(3H)-thione, C{sub 10}H{sub 14}N{sub 2}SSi, (3), are reported. Both systems were derived from 1H-benzimidazole-2(3H)-thione. Noncovalent C—H⋯π interactions between the centroid of the benzmidazole system and the SiMe{sub 3} groups form helicoidal arrangements in (2). Dimerization of (3) results in the formation of R{sub 2}{sup 2}(8) rings via N—H⋯S interactions, along with parallel π–π interactions between imidazole and benzene rings.

7. Infrared Predissociation Spectroscopy of the Hydrocarbon Cations C_3H^+, C_2H^+, and C_3H_2^+

Brünken, Sandra; Lipparini, Filippo; Gauss, Jürgen; Stoffels, Alexander; Redlich, Britta; van der Meer, Lex; Berden, Giel; Oomens, Jos; Schlemmer, Stephan

2016-06-01

Reactive hydrocarbon cations play an important role in the astrochemistry of the interstellar medium, but spectroscopic data, needed for their identification in astronomical observations, is sparse. Here we report the first gas-phase vibrational spectra of the linear C_3H^+ (^1 Σ), the radical cation C_2H^+ (^3 Π), and the linear-/cyclic-C_3H_2^+ (^2 Π /^2A_1, resp.). Broadband spectra were recorded by Ne- and He-messenger infrared-predissociation (IR-PD) action spectroscopy in a cryogenic (4-11 K) ion trap instrument (FELion) in the 250-3500 {wn} range using a free electron laser and a MIR-OPO at the FELIX (Free-Electron Laser for Infrared eXperiments) laboratory. The band positions (determined with a precision of 1-2 wn) covering the C-H and C-C stretching as well as several bending modes are compared to high-level (CCSD(T) with large basis sets) quantum-chemical calculations with an emphasis on anharmonic effects and on the influence of the rare-gas messenger atom. The experimental and theoretical data provide a solid basis for subsequent IR high-resolution studies, with the ultimate goal to predict and measure accurate rotational spectra for a radio-astronomical search of these molecular ions in space.

8. Determination of the delta(2H/1H)of Water: RSIL Lab Code 1574

USGS Publications Warehouse

Revesz, Kinga; Coplen, Tyler B.

2008-01-01

Reston Stable Isotope Laboratory (RSIL) lab code 1574 describes a method used to determine the relative hydrogen isotope-ratio delta(2H,1H), abbreviated hereafter as d2H of water. The d2H measurement of water also is a component of the National Water Quality Laboratory (NWQL) schedules 1142 and 1172. The water is collected unfiltered in a 60-mL glass bottle and capped with a Polyseal cap. In the laboratory, the water sample is equilibrated with gaseous hydrogen using a platinum catalyst (Horita, 1988; Horita and others, 1989; Coplen and others, 1991). The reaction for the exchange of one hydrogen atom is shown in equation 1.

9. Synthesis of (3) H, (2) H4 and (14) C-SCH 417690 (Vicriviroc).

PubMed

Hesk, D; Borges, S; Hendershot, S; Koharski, D; McNamara, P; Ren, S; Saluja, S; Truong, V; Voronin, K

2016-05-15

Vicriviroc or SCH 417690 is a potent and selective antagonist of the CCR5 receptor. CCR5 receptor antagonists have the potential for the treatment of HIV infections. Four distinct isotopically labelled forms of SCH 417690 were synthesized. Low specific activity [(3) H]SCH 417690 was prepared for a preliminary absorption, distribution, metabolism and excretion evaluation of the compound and [(14) C]SCH 417690 for more definitive absorption, distribution, metabolism and excretion work, including an absorption, metabolism and excretion study in man. In addition, high specific activity [(3) H]SCH 417690 was prepared for CCR5 receptor binding work and [(2) H4 ]SCH 417690 was prepared as an internal standard for a liquid chromatography-mass spectrometry bioanalytical method. The paper discusses the synthesis of four isotopically labelled forms of SCH 417690.

10. Characterization Results for the 2014 HTF 3H & 2H Evaporator Overhead Samples

SciTech Connect

Washington, A.

2015-05-11

This report tabulates the radiochemical analysis of the 3H and 2H evaporator overhead samples for 137Cs, 90Sr, and 129I to meet the requirements in the Effluent Treatment Project (ETP) Waste Acceptance Criteria (WAC) (rev. 6). This report identifies the sample receipt date, preparation method, and analysis performed in the accumulation of the listed values. All data was found to be within the ETP WAC (rev. 6) specification for the Waste Water Collection Tanks (WWCT).

11. NMR resonance splitting of urea in stretched hydrogels: proton exchange and (1)H/(2)H isotopologues.

PubMed

Kuchel, Philip W; Naumann, Christoph; Chapman, Bogdan E; Shishmarev, Dmitry; Håkansson, Pär; Bacskay, George; Hush, Noel S

2014-10-01

Urea at ∼12 M in concentrated gelatin gel, that was stretched, gave (1)H and (2)H NMR spectral splitting patterns that varied in a predictable way with changes in the relative proportions of (1)H2O and (2)H2O in the medium. This required consideration of the combinatorics of the two amide groups in urea that have a total of four protonation/deuteration sites giving rise to 16 different isotopologues, if all the atoms were separately identifiable. The rate constant that characterized the exchange of the protons with water was estimated by back-transformation analysis of 2D-EXSY spectra. There was no (1)H NMR spectral evidence that the chiral gelatin medium had caused in-equivalence in the protons bonded to each amide nitrogen atom. The spectral splitting patterns in (1)H and (2)H NMR spectra were accounted for by intra-molecular scalar and dipolar interactions, and quadrupolar interactions with the electric field gradients of the gelatin matrix, respectively.

12. Frequency Comb Assisted IR Measurements of H_3^+, H_2D^+ and D_2H^+ Transitions

Jusko, Pavol; Asvany, Oskar; Schlemmer, Stephan

2016-06-01

We present recent measurements of the fundamental transitions of H_3^+, H_2D^+ and D_2H^+ in a 4 K 22-pole trap by action spectroscopic techniques. Either Laser Induced Inhibition of Cluster Growth (He attachment at T≈4 K), endothermic reaction of H_3^+ with O_2, or deuterium exchange has been used as measurement scheme. We used a 3 μm optical parametric oscillator coupled to a frequency comb in order to achieve accuracy generally below 1 MHz. Five transitions of H_3^+, eleven of H_2D^+ and ten of D_2H^+ were recorder in our spectral range. We compare our H_3^+ results with two previous frequency comb assisted works. Moreover, accurate determination of the frequency allows us to predict pure rotational transitions for H_2D^+ and D_2H^+ in the THz range. P. Jusko, C. Konietzko, S. Schlemmer, O. Asvany, J. Mol. Spec. 319 (2016) 55 O. Asvany, S. Brünken, L. Kluge, S. Schlemmer, Appl. Phys. B 114 (2014) 203 O. Asvany, J. Krieg, S. Schlemmer, Rev. Sci. Instr. 83 (2012) 093110 J.N. Hodges, A.J. Perry, P.A. Jenkins, B.M. Siller, B.J. McCall, J. Chem. Phys. 139 (2013) 164201 H.-C. Chen, C.-Y. Hsiao, J.-L. Peng, T. Amano, J.-T. Shy, Phys. Rev. Lett. 109 (2012) 263002

13. An improved technique for the 2H/1H analysis of urines from diabetic volunteers

USGS Publications Warehouse

Coplen, T.B.; Harper, I.T.

1994-01-01

The H2-H2O ambient-temperature equilibration technique for the determination of 2H/1H ratios in urinary waters from diabetic subjects provides improved accuracy over the conventional Zn reduction technique. The standard deviation, ~ 1-2???, is at least a factor of three better than that of the Zn reduction technique on urinary waters from diabetic volunteers. Experiments with pure water and solutions containing glucose, urea and albumen indicate that there is no measurable bias in the hydrogen equilibration technique.The H2-H2O ambient-temperature equilibration technique for the determination of 2H/1H ratios in urinary waters from diabetic subjects provides improved accuracy over the conventional Zn reduction technique. The standard deviation, approximately 1-2%, is at least a factor of three better than that of the Zn reduction technique on urinary waters from diabetic volunteers. Experiments with pure water and solutions containing glucose, urea and albumen indicate that there is no measurable bias in the hydrogen equilibration technique.

14. a Rotational Study of 2H-3H-PERFLUOROPENTANE and its Isotopologues

Duong, Chinh H.; Obenchain, Daniel A.; Novick, Stewart E.; Cooke, S. A.

2012-06-01

The chirped pulse Fourier transform microwave spectrum of 2H-3H-perfluoropentane has been observed and assigned. Given a racemic mixture sample of the four available structural isomers, only the (S,S) structure was observed in the broadband spectrum. Attempts at observing the 13C isotopologues on a Balle-Flygare cavity type spectrometer and their assignments will be discussed, along with an examination of the theoretical predictions for the structure and rotational constants of the molecule against their experimental values. Structural results of the monomer will also be compared with those of the helical structure of C2 perfluoropentane. Joseph A. Fournier, Robert K. Bohn, John A. Montgomery Jr., Masao Onda. J. Phys. Chem. 114 (1118), 2010.

15. 1H-2H cross-polarization NMR in fast spinning solids by adiabatic sweeps

Wi, Sungsool; Schurko, Robert; Frydman, Lucio

2017-03-01

Cross-polarization (CP) experiments employing frequency-swept radiofrequency (rf) pulses have been successfully used in static spin systems for obtaining broadband signal enhancements. These experiments have been recently extended to heteronuclear I, S = spin-1/2 nuclides under magic-angle spinning (MAS), by applying adiabatic inversion pulses along the S (low-γ) channel while simultaneously applying a conventional spin-locking pulse on the I-channel (1H). This study explores an extension of this adiabatic frequency sweep concept to quadrupolar nuclei, focusing on CP from 1H (I = 1/2) to 2H spins (S = 1) undergoing fast MAS (νr = 60 kHz). A number of new features emerge, including zero- and double-quantum polarization transfer phenomena that depend on the frequency offsets of the swept pulses, the rf pulse powers, and the MAS spinning rate. An additional mechanism found operational in the 1H-2H CP case that was absent in the spin-1/2 counterpart, concerns the onset of a pseudo-static zero-quantum CP mode, driven by a quadrupole-modulated rf/dipolar recoupling term arising under the action of MAS. The best CP conditions found at these fast spinning rates correspond to double-quantum transfers, involving weak 2H rf field strengths. At these easily attainable (ca. 10 kHz) rf field conditions, adiabatic level-crossings among the {|1 ⟩ ,|0 ⟩ ,|-1 ⟩ } mS energy levels, which are known to complicate the CP MAS of quadrupolar nuclei, are avoided. Moreover, the CP line shapes generated in this manner are very close to the ideal 2H MAS spectral line shapes, facilitating the extraction of quadrupolar coupling parameters. All these features were corroborated with experiments on model compounds and justified using numerical simulations and average Hamiltonian theory models. Potential applications of these new phenomena, as well as extensions to higher spins S, are briefly discussed.

16. Nqrs Data for C3H12INO7 [C3H7NO2·HIO3·2(H2O)] (Subst. No. 0646)

Chihara, H.; Nakamura, N.

This document is part of Subvolume A Substances Containing Ag … C10H15' of Volume 48 Nuclear Quadrupole Resonance Spectroscopy Data' of Landolt-Börnstein - Group III Condensed Matter'. It contains an extract of Section 3.2 Data tables' of the Chapter 3 Nuclear quadrupole resonance data' providing the NQRS data for C3H12INO7 [C3H7NO2·HIO3·2(H2O)] (Subst. No. 0646)

17. Cometary implications of recent laboratory experiments on the photochemistry of the C2H and C3H2 radicals

NASA Technical Reports Server (NTRS)

Jackson, William M.; Bao, Yihan; Urdahl, Randall S.; Song, Xueyu; Gosine, Jai; Lu, Chi

1992-01-01

Recent laboratory results on the photodissociation of the C2H and C3H2 radicals are described. These studies show that the C2 and C3 radicals are produced by the 193 nm photolysis of the C2H and C3H2 radicals, respectively. The quantum state distributions that were determined for the C2 radicals put certain constraints on the initial conditions for any models of the observed C2 cometary spectra. Experimental observations of C2 formed by the 212.8 nm photolysis of C2H are used to calculate a range of photochemical lifetimes for the C2H radical.

18. Inhibition of myeloperoxidase: evaluation of 2H-indazoles and 1H-indazolones.

PubMed

Roth, Aaron; Ott, Sean; Farber, Kelli M; Palazzo, Teresa A; Conrad, Wayne E; Haddadin, Makhluf J; Tantillo, Dean J; Cross, Carroll E; Eiserich, Jason P; Kurth, Mark J

2014-11-15

Myeloperoxidase (MPO) produces hypohalous acids as a key component of the innate immune response; however, release of these acids extracellularly results in inflammatory cell and tissue damage. The two-step, one-pot Davis-Beirut reaction was used to synthesize a library of 2H-indazoles and 1H-indazolones as putative inhibitors of MPO. A structure-activity relationship study was undertaken wherein compounds were evaluated utilizing taurine-chloramine and MPO-mediated H2O2 consumption assays. Docking studies as well as toxicophore and Lipinski analyses were performed. Fourteen compounds were found to be potent inhibitors with IC50 values <1μM, suggesting these compounds could be considered as potential modulators of pro-oxidative tissue injury pertubated by the inflammatory MPO/H2O2/HOCl/HOBr system.

19. The Cac1 subunit of histone chaperone CAF-1 organizes CAF-1-H3/H4 architecture and tetramerizes histones

PubMed Central

Liu, Wallace H; Roemer, Sarah C; Zhou, Yeyun; Shen, Zih-Jie; Dennehey, Briana K; Balsbaugh, Jeremy L; Liddle, Jennifer C; Nemkov, Travis; Ahn, Natalie G; Hansen, Kirk C; Tyler, Jessica K; Churchill, Mair EA

2016-01-01

The histone chaperone Chromatin Assembly Factor 1 (CAF-1) deposits tetrameric (H3/H4)2 histones onto newly-synthesized DNA during DNA replication. To understand the mechanism of the tri-subunit CAF-1 complex in this process, we investigated the protein-protein interactions within the CAF-1-H3/H4 architecture using biophysical and biochemical approaches. Hydrogen/deuterium exchange and chemical cross-linking coupled to mass spectrometry reveal interactions that are essential for CAF-1 function in budding yeast, and importantly indicate that the Cac1 subunit functions as a scaffold within the CAF-1-H3/H4 complex. Cac1 alone not only binds H3/H4 with high affinity, but also promotes histone tetramerization independent of the other subunits. Moreover, we identify a minimal region in the C-terminus of Cac1, including the structured winged helix domain and glutamate/aspartate-rich domain, which is sufficient to induce (H3/H4)2 tetramerization. These findings reveal a key role of Cac1 in histone tetramerization, providing a new model for CAF-1-H3/H4 architecture and function during eukaryotic replication. DOI: http://dx.doi.org/10.7554/eLife.18023.001 PMID:27690308

20. Hydrochemistry and 18O/16O and 2H/1H Ratios of Ugandan Waters

Gebremichael, M. G.; Jasechko, S.

2013-12-01

Today, 70% of the 35 million people living in Uganda have access to an improved water source, ranking Uganda 148 out of 179 nations reporting in 2010 (Millennium Development Goals Indicators). 80% of Ugandans rely on groundwater as their primary drinking water source, collecting at springs or from shallow wells. Similarly, 80% of Ugandans rely upon agriculture - usually rain fed - as their primary income source. Despite lack of access to protected water sources faced by 10 million Ugandans, and the importance of the blue economy to Uganda's continued development, a country-wide investigation of the chemistry and the stable oxygen and hydrogen isotope compositions of waters has yet to be completed. Here we present 250 analyses of 18O/16O, 2H/1H and dissolved ion concentrations of Ugandan lakes, rivers, groundwaters and springs collected during July, 2013. We use the new data to characterize regional scale groundwater recharge sources, advection pathways and interactions with surface waters. Large lakes - Albert, Edward and Victoria - show increases in 18O/16O and 2H/1H ratios consistent with open water evaporation, and are shown to be distinct from nearby groundwaters, suggesting minimal recharge from large lakes to the subsurface. Salinities of eastern Ugandan groundwaters are elevated relative to samples collected from the central and western regions, suggesting that longer groundwater residence times and enhanced water-rock interactions characterize these waters. Springs from western Uganda show a shift in 18O/16O to higher values as a result of hydrothermal water-rock exchanges. Dissolved ion and noble gas concentrations show potential for use in assessing geothermal energy resources, perhaps aiding the Ugandan Ministry for Energy, Minerals and Development to meet their goal of increasing renewable energy from 4% (current) to 61% of total use by 2017 (Nyakabwa-Atwoki, 2013). Millennium Development Goals Indicators. mdgs.un.org/unsd/mdg/data.aspx Nyakabwa

1. Equilibrium 2H/1H fractionation in organic molecules: III. Cyclic ketones and hydrocarbons

Wang, Ying; Sessions, Alex L.; Nielsen, Robert J.; Goddard, William A.

2013-04-01

Quantitative interpretation of stable hydrogen isotope ratios (2H/1H) in organic compounds is greatly aided by knowledge of the relevant equilibrium fractionation factors (ɛeq). Previous efforts have combined experimental measurements and hybrid Density Functional Theory (DFT) calculations to accurately predict equilibrium fractionations in linear (acyclic) organic molecules (Wang et al., 2009a,b), but the calibration produced by that study is not applicable to cyclic compounds. Here we report experimental measurements of equilibrium 2H/1H fractionation in six cyclic ketones, and use those data to evaluate DFT calculations of fractionation in diverse monocyclic and polycyclic compounds commonly found in sedimentary organic matter and petroleum. At 25, 50, and 75 °C, the experimentally measured ɛeq values for secondary and tertiary Hα in isotopic equilibrium with water are in the ranges of -130‰ to -150‰ and +10‰ to -40‰ respectively. Measured data are similar to DFT calculations of ɛeq for axial Hα but not equatorial Hα. In tertiary Cα positions with methyl substituents, this can be understood as a result of the methyl group forcing Hα atoms into a dominantly axial position. For secondary Cα positions containing both axial and equatorial Hα atoms, we propose that axial Hα exchanges with water significantly faster than the equatorial Hα does, due to the hyperconjugation-stabilized transition state. Interconversion of axial and equatorial positions via ring flipping is much faster than isotopic exchange at either position, and as a result the steady-state isotopic composition of both H's is strongly weighted toward that of axial Hα. Based on comparison with measured ɛeq values, a total uncertainty of 10-30‰ remains for theoretical ɛeq values. Using DFT, we systematically estimated the ɛeq values for individual H positions in various cyclic structures. By summing over all individual H positions, the molecular equilibrium fractionation was

2. Ab initio study of {sup 2}H(d,{gamma}){sup 4}He, {sup 2}H(d,p){sup 3}H, and {sup 2}H(d,n){sup 4}He reactions and the tensor force

SciTech Connect

Arai, K.; Aoyama, S.; Suzuki, Y.; Descouvemont, P.; Baye, D.

2012-11-12

The {sup 2}H(d,p){sup 3}H, {sup 2}H(d,n){sup 3}He, and {sup 2}H(d,{gamma}){sup 4}He reactions at low energies are studied with realistic nucleon-nucleon interactions in an ab initio approach. The obtained astrophysical S-factors are all in very good agreement with experiment. The most important channels for both transfer and radiative capture are all found to dominate thanks to the tensor force.

3. Ligand-promoted alkylation of C(sp3)-H and C(sp2)-H bonds.

PubMed

Zhu, Ru-Yi; He, Jian; Wang, Xiao-Chen; Yu, Jin-Quan

2014-09-24

9-Methylacridine was identified as a generally effective ligand to promote a Pd(II)-catalyzed C(sp(3))-H and C(sp(2))-H alkylation of simple amides with various alkyl iodides. This alkylation reaction was applied to the preparation of unnatural amino acids and geometrically controlled tri- and tetrasubstituted acrylic acids.

4. Photoabsorption and photoionization cross sections of NH3, PH3, H2S, C2H2, and C2H4 in the VUV region

NASA Technical Reports Server (NTRS)

Xia, T. J.; Chien, T. S.; Wu, C. Y. Robert; Judge, D. L.

1991-01-01

Using synchrotron radiation as a continuum light source, the photoabsorption and photoionization cross sections of NH3, PH3, H2S, C2H2, and C2H4 have been measured from their respective ionization thresholds to 1060 A. The vibrational constants associated with the nu(2) totally symmetric, out-of-plane bending vibration of the ground electronic state of PH3(+) have been obtained. The cross sections and quantum yields for producing neutral products through photoexcitation of these molecules in the given spectral regions have also been determined. In the present work, autoionization processes were found to be less important than dissociation and predissociation processes in NH3, PH3, and C2H4. Several experimental techniques have been employed in order to examine the various possible systematic errors critically.

5. Understanding 2H/1H systematics of leaf wax n-alkanes in coastal plants at Stiffkey saltmarsh, Norfolk, UK

Eley, Yvette; Dawson, Lorna; Black, Stuart; Andrews, Julian; Pedentchouk, Nikolai

2014-03-01

Interpretation of sedimentary n-alkyl lipid δ2H data is complicated by a limited understanding of factors controlling interspecies variation in biomarker 2H/1H composition. To distinguish between the effects of interrelated environmental, physical and biochemical controls on the hydrogen isotope composition of n-alkyl lipids, we conducted linked δ2H analyses of soil water, xylem water, leaf water and n-alkanes from a range of C3 and C4 plants growing at a UK saltmarsh (i) across multiple sampling sites, (ii) throughout the 2012 growing season, and (iii) at different times of the day. Soil waters varied isotopically by up to 35‰ depending on marsh sub-environment, and exhibited site-specific seasonal shifts in δ2H up to a maximum of 31‰. Maximum interspecies variation in xylem water was 38‰, while leaf waters differed seasonally by a maximum of 29‰. Leaf wax n-alkane 2H/1H, however, consistently varied by over 100‰ throughout the 2012 growing season, resulting in an interspecies range in the ɛwax/leaf water values of -79‰ to -227‰. From the discrepancy in the magnitude of these isotopic differences, we conclude that mechanisms driving variation in the 2H/1H composition of leaf water, including (i) spatial changes in soil water 2H/1H, (ii) temporal changes in soil water 2H/1H, (iii) differences in xylem water 2H/1H, and (iv) differences in leaf water evaporative 2H-enrichment due to varied plant life forms, cannot explain the range of n-alkane δ2H values we observed. Results from this study suggests that accurate reconstructions of palaeoclimate regimes from sedimentary n-alkane δ2H require further research to constrain those biological mechanisms influencing species-specific differences in 2H/1H fractionation during lipid biosynthesis, in particular where plants have developed biochemical adaptations to water-stressed conditions. Understanding how these mechanisms interact with environmental conditions will be crucial to ensure accurate

6. 1-Allyl-3-benzyl-1H-benzimidazol-2(3H)-one

PubMed Central

Kandri Rodi, Youssef; Haoudi, Amal; Capet, Frédéric; Mazzah, Ahmed; Essassi, El Mokhtar; El Ammari, Lahcen

2013-01-01

In the title compound, C17H16N2O, the fused benzimidazol-2(3H)-one system is essentially planar, the largest deviation from the mean plane being 0.006 (2) Å for the carbonyl C atom. Its mean plane is almost perpendicular to the benzyl plane and to the allyl group, making dihedral angles of 80.6 (1) and 77.4 (3)°, respectively. The benzyl group and the allyl subsituent lie on opposite sides of the fused ring system. In the crystal, mol­ecules are linked by bifurcated C—H⋯O hydrogen bonds in which the carbonyl O atom acts as accepter to two aromatic C—H groups, forming a two-dimensional network parallel to (001). PMID:24427099

7. (2)H-decoupling-accelerated (1)H spin diffusion in dynamic nuclear polarization with photoexcited triplet electrons.

PubMed

Negoro, M; Nakayama, K; Tateishi, K; Kagawa, A; Takeda, K; Kitagawa, M

2010-10-21

In dynamic nuclear polarization (DNP) experiments applied to organic solids for creating nonequilibrium, high (1)H spin polarization, an efficient buildup of (1)H polarization is attained by partially deuterating the material of interest with an appropriate (1)H concentration. In such a dilute (1)H spin system, it is shown that the (1)H spin diffusion rate and thereby the buildup efficiency of (1)H polarization can further be enhanced by continually applying radiofrequency irradiation for deuterium decoupling during the DNP process. As experimentally confirmed in this work, the electron spin polarization of the photoexcited triplet state is mainly transferred only to those (1)H spins, which are in the vicinity of the electron spins, and (1)H spin diffusion transports the localized (1)H polarization over the whole sample volume. The (1)H spin diffusion coefficients are estimated from DNP repetition interval dependence of the initial buildup rate of (1)H polarization, and the result indicates that the spin diffusion coefficient is enhanced by a factor of 2 compared to that without (2)H decoupling.

8. Controls on compound specific 2H/1H of leaf waxes along a North American monsoonal transect

Berke, M. A.; Tipple, B. J.; Hambach, B.; Ehleringer, J. R.

2013-12-01

The use of hydrogen isotope ratios of sedimentary n-alkanes from leaf waxes has become an important method for the reconstruction of paleohydrologic conditions. Ideally, the relationship between lipid 2H/1H values and source water is one-to-one. But the extent to which the 2H/1H values are altered between initial source water and lipid 2H/1H values varies by plant type and environment. Additionally, these variables may be confounded by use of varied source waters by plants in the same ecosystem. Here, we use a transect study across the arid southwestern landscape of the United States, which is heavily influenced by the North American Monsoon, to study the variability in 2H/1H values of leaf waxes in co-occurring plants from Tucson, Arizona to Salt Lake City, Utah. Perennials, including rabbit brush (Chrysothamnus nauseosus), sagebrush (Artemisia tridentata), and gambel oak (Quercus gambelii) and an annual plant, sunflower (Helianthus annuus), were chosen for their wide geographic distribution along the entire transect. Our results indicate that n-alkane distribution for each plant was similar and generally showed no relationship to environmental variables (elevation, mean annual precipitation, latitude, and temperature). However, we find evidence of n-alkane 2H/1H value relating to transect latitude, a relationship that is weaker for all samples combined than the strong individual correlation for each plant species. Further, these 2H/1H values suggest that not all plants in the monsoon region utilize monsoon-delivered precipitation. These results imply an adaptation to discontinuous spatial coverage and amount of monsoonal precipitation and suggest care must be taken when assuming consistent source water for different plants, particularly in regions with highly seasonal precipitation delivery.

9. 6-Bromo-3-methyl-1H-imidazo[4,5-b]pyridin-2(3H)-one

PubMed Central

Ghacham, Hend Bel; Rodi, Youssef Kandri; Capet, Frédéric; Essassi, El Mokhtar; Ng, Seik Weng

2010-01-01

The title compound, C7H6BrN3O, was obtained from the reaction of 6-bromo-1H-imidazo[4,5-b]pyridin-2(3H)-one with methyl iodide. All non-H atoms lie in a common plane [r.m.s deviation = 0.017 (1) Å]. The amino group is a hydrogen-bond donor to the carbonyl group of an inversion-related mol­ecule, the pair of hydrogen bonds giving rise to a hydrogen-bonded dimer. PMID:21579134

10. Synthesis and biological evaluation of a new furo[2,3-h]quinolin-2(1H)-one.

PubMed

Chilin, Adriana; Marzano, Christine; Guiotto, Adriano; Baccichetti, Francarosa; Carlassare, Francesco; Bordin, Franco

2002-02-28

A new furoquinolinone derivative, namely 4-hydroxymethyl-1,6,8-trimethylfuro[2,3-h]quinolin-2(1H)-one (HOFQ), was synthesized and its biological activity studied. By UVA activation, HOFQ induced strong antiproliferative effects in Ehrlich ascite cells, which lost their ability to transmit the tumor by transplantation. HOFQ exhibited poor genotoxicity and absence of skin phototoxicity. Actually, HOFQ sensitization forms DNA-protein cross-linkages but not interstrands cross-links. Therefore, HOFQ appears to be a new promising drug for PUVA photochemotherapy and photopheresis.

11. Osmium(IV) complexes with 1H- and 2H-indazoles: tautomer identity versus spectroscopic properties and antiproliferative activity.

PubMed

Büchel, Gabriel E; Stepanenko, Iryna N; Hejl, Michaela; Jakupec, Michael A; Keppler, Bernhard K; Heffeter, Petra; Berger, Walter; Arion, Vladimir B

2012-08-01

A one-pot synthesis of osmium(IV) complexes with two different tautomers of indazole, 1H-indazole and 2H-indazole, namely (H(2)ind)[Os(IV)Cl(5)(2H-ind)] (1) and (H(2)ind)[Os(IV)Cl(5)(1H-ind)] (2) is reported. Both compounds have been comprehensively characterized by NMR spectroscopy, ESI (electrospray ionization) mass spectrometry, electronic absorption spectroscopy, IR spectroscopy, cyclic voltammetry and tested for antiproliferative activity in vitro in three human cancer cell lines, CH1 (ovarian carcinoma), A549 (non-small cell lung cancer) and SW480 (colon carcinoma), as well as in vivo in a Hep3B SCID mouse xeno-transplantation model. 2H-Indazole tautomer stabilization in 1 has been confirmed by X-ray diffraction.

12. Measurement of the 2H(d ,p ) 3H reaction at astrophysical energies via the Trojan-horse method

Li, Chengbo; Wen, Qungang; Fu, Yuanyong; Zhou, Jing; Zhou, Shuhua; Meng, Qiuying; Spitaleri, C.; Tumino, A.; Pizzone, R. G.; Lamia, L.

2015-08-01

The study of the 2H(d ,p ) 3H reaction is very important for the nucleosynthesis in both the standard Big Bang and stellar evolution, as well as for the future fusion reactor's planning of energy production. The 2H(d ,p ) 3H bare nucleus astrophysical S (E ) factor has been measured indirectly at energies from about 400 keV down to several keV by means of the Trojan-horse method applied to the quasifree process 2H(6Li ,p t ) 4He induced at a lithium beam energy of 9.5 MeV, which is closer to the zero-quasifree-energy point. An accurate analysis leads to the determination of the Sbare(0 ) =56.7 ±2.0 keV b and of the corresponding electron screening potential Ue=13.2 ±4.3 eV. In addition, this work gives an updated test for the Trojan-horse nucleus invariance by comparing with previous indirect investigations using the 3He=(d +p ) breakup.

13. Abstraction and addition kinetics of C2H radicals with CH4, C2H6, C3H8, C2H4, and C3H6: CVT/SCT/ISPE and hybrid meta-DFT methods.

PubMed

Dash, Manas Ranjan; Rajakumar, B

2015-02-07

Rate coefficients for the reactions of C2H radicals with methane (k1), ethane (k2), propane (k3), ethylene (k4), and propylene (k5) were computed using canonical variational transition state theory (CVT) coupled with hybrid-meta density functional theory (DFT) over a wide range of temperatures from 150 to 5000 K. The quantum chemical tunneling effect was corrected by the small curvature tunneling (SCT) method. The dynamic calculations are performed using the variational transition state theory (VTST) with the interpolated single-point energies (ISPE) method at the CCSD(T)/cc-pVTZ//M06-2X/6-31+G(d,p) level of theory. Intrinsic reaction coordinate (IRC) calculations were performed to verify that the transition states are connected to the reactants and products. The rate coefficients obtained over the studied temperature range yield the following Arrhenius expressions (cm(3) molecule(-1) s(-1)): k1 = 4.69 × 10(-19)T(2.44) exp[331/T], k2 = 4.29 × 10(-17)T(2.11) exp[432/T], k3 = 4.81 × 10(-17)T(1.98) exp[697/T], k4 = 7.54 × 10(-21)T(2.96) exp[1942/T], and k5 = 8.04 × 10(-23)T(3.44) exp[3011/T] cm(3) molecule(-1) s(-1). Branching ratio calculation for the reactions of C2H radicals with ethylene and propylene shows that the abstraction reactions are not important at lower temperatures. However, as the temperature increases, abstraction reactions become more important.

14. Tensor Force Manifestations in Ab Initio Study of the {sup 2}H(d,{gamma}){sup 4}He, {sup 2}H(d,p){sup 3}H, and {sup 2}H(d,n){sup 3}He Reactions

SciTech Connect

Arai, K.; Aoyama, S.; Suzuki, Y.; Descouvemont, P.; Baye, D.

2011-09-23

The {sup 2}H(d,p){sup 3}H, {sup 2}H(d,n){sup 3}He, and {sup 2}H(d,{gamma}){sup 4}He reactions are studied at low energies in a multichannel ab initio model that takes into account the distortions of the nuclei. The internal wave functions of these nuclei are given by the stochastic variational method with the AV8{sup '} realistic interaction and a phenomenological three-body force included to reproduce the two-body thresholds. The obtained astrophysical S factors are all in very good agreement with the experiment. The most important channels for both transfer and radiative capture are identified by comparing to calculations with an effective central force. They are all found to dominate thanks to the tensor force.

15. Syntheses of (3) H-labeled, (14) C-labeled, and (2) H4 -labeled SCH 444877, phosphodiesterase type 5 inhibitors.

PubMed

Ren, Sumei; Hesk, David; McNamara, Paul; Koharski, David; Hendershot, Sharon

2013-01-01

The syntheses of [(3) H]SCH 444877, [(2) H4 ]SCH 444877, and [(14) C]SCH 444877 are described. [(3) H]SCH 444877 was prepared in three steps from tritium gas. [(2) H4 ]SCH 444877 was synthesized from [(2) H4 ]ethanolamine in four steps with an overall yield of 40%. [(14) C]SCH 444877 was prepared from barium [(14) C]cyanamide in 10 steps with an overall yield of 8.1%.

16. Observation of enhanced rate coefficients in the H2 + + H 2 → H3 + + H reaction at low collision energies

Allmendinger, Pitt; Deiglmayr, Johannes; Höveler, Katharina; Schullian, Otto; Merkt, Frédéric

2016-12-01

The energy dependence of the rate coefficient of the H2 + + H 2 → H3 + + H reaction has been measured in the range of collision energies between k B ṡ 10 K and k B ṡ 300 mK . A clear deviation of the rate coefficient from the value expected on the basis of the classical Langevin-capture behavior has been observed at collision energies below k B ṡ 1 K , which is attributed to the joint effects of the ion-quadrupole and Coriolis interactions in collisions involving ortho-H2 molecules in the j = 1 rotational level, which make up 75% of the population of the neutral H2 molecules in the experiments. The experimental results are compared to very recent predictions by Dashevskaya et al. [J. Chem. Phys. 145, 244315 (2016)], with which they are in agreement.

17. Homocatenation of aluminum: alkane-like structures of Li2Al2H6 and Li3Al3H8.

PubMed

Gish, J Tyler; Popov, Ivan A; Boldyrev, Alexander I

2015-03-27

A new class of aluminum homocatenated compounds (LinAlnH2n+2) is proposed based on quantum chemical calculations. In these compounds, Al abstracts an electron from Li, becoming valence isoelectronic with C, Si, and Ge, thus mimicking respective structural features of Group 14 hydrides. Using the Coalescence Kick search program coupled with density functional theory calculations, we investigated the potential energy surfaces of Li2Al2 H6 and Li3Al3H6 . Then single-point-energy coupled-cluster calculations were performed for the lowest energy structures found. Indeed, the global minima established for Li2 Al2 H6 and Li3 Al3 H6 contain the Al2 H6(2-) and Al3H6(3-) kernels, which are isostructural with ethane (C2H6), disilane (Si2H6), digermane (Ge2 H6) and propane (C3H8), trisilane (Si3H8), trigermane (Ge3H8) molecules, respectively. Structural, energetic, and electronic characteristics of the Li2 Al2 H6 and Li3 Al3 H8 compounds are presented and the viability of their synthesis is discussed.

18. In-silico docking based design and synthesis of [1H,3H] imidazo[4,5-b] pyridines as lumazine synthase inhibitors for their effective antimicrobial activity

PubMed Central

Harer, Sunil L.; Bhatia, Manish S.

2014-01-01

Purpose: The imidazopyridine moiety is important pharmacophore that has proven to be useful for a number of biologically relevant targets, also reported to display antibacterial, antifungal, antiviral properties. Riboflavin biosynthesis involving catalytic step of Lumazine synthase is absent in animals and human, but present in microorganism, one of marked advantage of this study. Still, this path is not exploited as antiinfective target. Here, we proposed different interactions between [1H,3H] imidazo[4,5-b] pyridine test ligands and target protein Lumazine synthase (protein Data Bank 2C92), one-step synthesis of title compounds and further evaluation of them for in vitro antimicrobial activity. Materials and Methods: Active pocket of the target protein involved in the interaction with the test ligands molecules was found using Biopredicta tools in VLifeMDS 4.3 Suite. In-silico docking suggests H-bonding, hydrophobic interaction, charge interaction, aromatic interaction, and Vanderwaal forces responsible for stabilizing enzyme-inhibitor complex. Disc diffusion assay method was used for in vitro antimicrobial screening. Results and Discussion: Investigation of possible interaction between test ligands and target lumazine synthase of Mycobacterium tuberculosis suggested 1i and 2f as best fit candidates showing hydrogen bonding, hydrophobic, aromatic and Vanderwaal's forces. Among all derivatives 1g, 1j, 1k, 1l, 2a, 2c, 2d, 2e, 2h, and 2j exhibited potent activities against bacteria and fungi compared to the standard Ciprofloxacin and Fluconazole, respectively. The superiority of 1H imidazo [4,5-b] pyridine compounds having R’ = Cl >No2 > NH2 at the phenyl/aliphatic moiety resident on the imidazopyridine, whereas leading 3H imidazo[4,5-b] pyridine compounds containing R/Ar = Cl > No2 > NH2> OCH3 substituents on the 2nd position of imidazole. PMID:25400412

19. 40 CFR 721.5540 - 1H,3H,5H-oxazolo [3,4-c] oxazole, dihydro-7a-methyl-.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 40 Protection of Environment 31 2014-07-01 2014-07-01 false 1H,3H,5H-oxazolo oxazole, dihydro-7a... Specific Chemical Substances § 721.5540 1H,3H,5H-oxazolo oxazole, dihydro-7a-methyl-. (a) Chemical...-oxazolo oxazole, dihydro-7a-methyl- (PMN P-91-1324) is subject to reporting under this section for...

20. 40 CFR 721.5540 - 1H,3H,5H-oxazolo [3,4-c] oxazole, dihydro-7a-methyl-.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 40 Protection of Environment 32 2013-07-01 2013-07-01 false 1H,3H,5H-oxazolo oxazole, dihydro-7a... Specific Chemical Substances § 721.5540 1H,3H,5H-oxazolo oxazole, dihydro-7a-methyl-. (a) Chemical...-oxazolo oxazole, dihydro-7a-methyl- (PMN P-91-1324) is subject to reporting under this section for...

1. 40 CFR 721.5540 - 1H,3H,5H-oxazolo [3,4-c] oxazole, dihydro-7a-methyl-.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 31 2011-07-01 2011-07-01 false 1H,3H,5H-oxazolo oxazole, dihydro-7a... Specific Chemical Substances § 721.5540 1H,3H,5H-oxazolo oxazole, dihydro-7a-methyl-. (a) Chemical...-oxazolo oxazole, dihydro-7a-methyl- (PMN P-91-1324) is subject to reporting under this section for...

2. 40 CFR 721.5540 - 1H,3H,5H-oxazolo [3,4-c] oxazole, dihydro-7a-methyl-.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 40 Protection of Environment 32 2012-07-01 2012-07-01 false 1H,3H,5H-oxazolo oxazole, dihydro-7a... Specific Chemical Substances § 721.5540 1H,3H,5H-oxazolo oxazole, dihydro-7a-methyl-. (a) Chemical...-oxazolo oxazole, dihydro-7a-methyl- (PMN P-91-1324) is subject to reporting under this section for...

3. Specific nonpeptide inhibitors of puromycin-sensitive aminopeptidase with a 2,4(1H,3H)-quinazolinedione skeleton.

PubMed

Kakuta, Hiroki; Tanatani, Aya; Nagasawa, Kazuo; Hashimoto, Yuichi

2003-11-01

Potent, specific, chemically stable and non-peptide/small-molecular inhibitors of puromycin-sensitive aminopeptidase, such as 3-(2,6-diethylphenyl)-2,4(1H,3H)-quinazolinedione (PAQ-22, 5), were prepared by the structural development of a potent PSA inhibitor, 2-(2,6-diethylphenyl)-1,2,3,4-tetrahydroisoquinoline-1,3-dione (PIQ-22, 4). The design was carried out partly by applying electrostatic potential field information obtained from PIQ-22 (4) and its derivatives based on thalidomide (2). This information revealed that a positive electrostatic potential field around the benzylic methylene in the tetrahydroisoquinoline ring is necessary for potent activity. Lineweaver-Burk plot analysis showed that PAQ-22 (5) and its derivatives inhibit puromycin-sensitive aminopeptidase (PSA) in a non-competitive manner. These potent and specific PSA inhibitors showed dose-dependent cell invasion-inhibitory activity in a Matrigel assay using mouse melanoma B16F10/L5 cells, in spite of their low cell toxicity.

4. Measurements of intracellular volumes by 59Co and 2H/1H NMR and their physiological applications.

PubMed

2005-04-01

Determination of the intracellular water volumes using NMR spectroscopy was performed using the NMR-visible nuclei: 59Co and 2H or 1H. Accurate measurement of intracellular water in cell suspensions and perfused organs is an important physiological parameter in the context of electrolyte homeostasis and energy metabolism, in particular when these parameters are monitored by non-invasive NMR spectroscopy. Furthermore, repeated or continuous monitoring of intracellular water provided significant insights into the physiology of cardiac muscle and sarcolemmal membrane permeability and integrity.

5. Synthesis of 3H, 13C,2H3,15N and 14C-labelled SCH 466036, a histamine 3 receptor antagonist.

PubMed

Hesk, D; Borges, S; Dumpit, R; Hendershot, S; Koharski, D; Lavey, C; McNamara, P; Voronin, K

2015-02-01

The synthesis of [(3)H]SCH 466036, [Me-(3)H3]SCH 466036, [(13)C,(2)H3,(15)N]SCH 466036 and [(14)C]SCH 466036 is described. [(3)H]SCH 466036 was prepared in two steps via Raney Ni-catalysed exchange with tritiated water. [Me-(3)H3]SCH 466036 was prepared in a single step from [(3)H]methyl iodide in 45% yield. [(13)C,(2)H3,(15)N]SCH 466036 was prepared in two steps from [(15)N]hydroxylamine and [(13)C,(2)H3]methyl iodide with an overall yield of 16%. [(14)C]SCH 466036 was prepared in seven steps from [(14)C]potassium cyanide in an overall yield of 13%.

6. 2H,3H-decafluoropentane-based nanodroplets: new perspectives for oxygen delivery to hypoxic cutaneous tissues.

PubMed

Prato, Mauro; Magnetto, Chiara; Jose, Jithin; Khadjavi, Amina; Cavallo, Federica; Quaglino, Elena; Panariti, Alice; Rivolta, Ilaria; Benintende, Emilio; Varetto, Gianfranco; Argenziano, Monica; Troia, Adriano; Cavalli, Roberta; Guiot, Caterina

2015-01-01

Perfluoropentane (PFP)-based oxygen-loaded nanobubbles (OLNBs) were previously proposed as adjuvant therapeutic tools for pathologies of different etiology sharing hypoxia as a common feature, including cancer, infection, and autoimmunity. Here we introduce a new platform of oxygen nanocarriers, based on 2H,3H-decafluoropentane (DFP) as core fluorocarbon. These new nanocarriers have been named oxygen-loaded nanodroplets (OLNDs) since DFP is liquid at body temperature, unlike gaseous PFP. Dextran-shelled OLNDs, available either in liquid or gel formulations, display spherical morphology, ~600 nm diameters, anionic charge, good oxygen carrying capacity, and no toxic effects on human keratinocytes after cell internalization. In vitro OLNDs result more effective in releasing oxygen to hypoxic environments than former OLNBs, as demonstrated by analysis through oxymetry. In vivo, OLNDs effectively enhance oxy-hemoglobin levels, as emerged from investigation by photoacoustic imaging. Interestingly, ultrasound (US) treatment further improves transdermal oxygen release from OLNDs. Taken together, these data suggest that US-activated, DFP-based OLNDs might be innovative, suitable and cost-effective devices to topically treat hypoxia-associated pathologies of the cutaneous tissues.

7. 2H,3H-Decafluoropentane-Based Nanodroplets: New Perspectives for Oxygen Delivery to Hypoxic Cutaneous Tissues

PubMed Central

Jose, Jithin; Khadjavi, Amina; Cavallo, Federica; Quaglino, Elena; Panariti, Alice; Rivolta, Ilaria; Benintende, Emilio; Varetto, Gianfranco; Argenziano, Monica; Troia, Adriano; Cavalli, Roberta; Guiot, Caterina

2015-01-01

Perfluoropentane (PFP)-based oxygen-loaded nanobubbles (OLNBs) were previously proposed as adjuvant therapeutic tools for pathologies of different etiology sharing hypoxia as a common feature, including cancer, infection, and autoimmunity. Here we introduce a new platform of oxygen nanocarriers, based on 2H,3H-decafluoropentane (DFP) as core fluorocarbon. These new nanocarriers have been named oxygen-loaded nanodroplets (OLNDs) since DFP is liquid at body temperature, unlike gaseous PFP. Dextran-shelled OLNDs, available either in liquid or gel formulations, display spherical morphology, ~600 nm diameters, anionic charge, good oxygen carrying capacity, and no toxic effects on human keratinocytes after cell internalization. In vitro OLNDs result more effective in releasing oxygen to hypoxic environments than former OLNBs, as demonstrated by analysis through oxymetry. In vivo, OLNDs effectively enhance oxy-hemoglobin levels, as emerged from investigation by photoacoustic imaging. Interestingly, ultrasound (US) treatment further improves transdermal oxygen release from OLNDs. Taken together, these data suggest that US-activated, DFP-based OLNDs might be innovative, suitable and cost-effective devices to topically treat hypoxia-associated pathologies of the cutaneous tissues. PMID:25781463

8. Derivatives of 1,3-disubstituted 2,4(1H,3H)-quinazolinediones as possible peripheral vasodilators or antihypertensive agents.

PubMed

Havera, H J; Vidrio, H

1979-12-01

A series of 1,3-disubstituted 2,4(1H,3H)-quinazolinediones was prepared from the 3-substituted 2,4(1H,3H)-quinazolinediones by treatment with sodium hydride and the desired alkyl halide in xylene. These compounds showed varying degrees of vasodilation and antihypertensive activity without significant blockade of alpha-adrenergic receptors. 1-[3-(N,N-Dimethylamino)propyl]-3-[3-(4-phenyl1-piperazinyl)propyl]-2,4(1H,3H)-quinazolinedione, which was selected for further studies, was more potent than papaverine in inducing vasodilation and induced a prolonged decrease in systolic blood pressure of hypertensive rats upon oral administration.

9. Nqrs Data for C3H10INO6 [C3H7NO2·HIO3·(1/2)(H2O)] (Subst. No. 0642)

Chihara, H.; Nakamura, N.

This document is part of Subvolume A Substances Containing Ag … C10H15' of Volume 48 Nuclear Quadrupole Resonance Spectroscopy Data' of Landolt-Börnstein - Group III Condensed Matter'. It contains an extract of Section 3.2 Data tables' of the Chapter 3 Nuclear quadrupole resonance data' providing the NQRS data for C3H10INO6 [C3H7NO2·HIO3·(1/2)(H2O)] (Subst. No. 0642)

10. Water - Isotope - Map (δ 18O, δ 2H, 3H) of Austria: Applications, Extremes and Trends

Wyhlidal, Stefan; Kralik, Martin; Benischke, Ralf; Leis, Albrecht; Philippitsch, Rudolf

2016-04-01

The isotopic ratios of oxygen and hydrogen in water (2H/1H and 18O/16O) are important tools to characterise waters and their cycles. This starts in the atmosphere as rain or snow and continues in surface water and ends in shallow groundwater as well as in deep groundwater. Tritium formed by natural cosmic radiation in the upper atmosphere and in the last century by tests of thermonuclear bombs in the atmosphere, is characterised by its radioactive decay with a half-life of 12.32 years and is an ideal age-marker during the last 60 years. To determine the origin and mean age of waters in many projects concerning water supply, engineering and scientific projects in the last 45 years on more than 1,350 sites, more than 40,000 isotope measurements were performed in Austria. The median value of all sites of oxygen-18 is δ 18O -10.7 ‰ and for hydrogen-2 δ 2H -75 ‰. As the fractionation is mainly temperature dependent the lowest negative values are observed in winter precipitation (oxygen-18 as low as δ 18O -23 ‰) and in springs in the mountain regions (δ 18O -15.1 ‰). In contrast the highest values were observed in summer precipitation (up to δ 18O - 0.5 ‰) and in shallow lakes in the Seewinkel (up to δ 18O + 5 ‰). The isotopic ratios of the Austrian waters are also influenced by the origin of the evaporated water masses. Therefore the precipitation in the region south of the main Alpine crest (East-Tyrol, Carinthia and South-East Styria) is approximately 1 ‰ higher in δ 18O-values than sites at the same altitude in the northern part. This is most probably caused by the stronger influence of precipitation from the mediterranean area. The median value of all 1,120 sampling sites of decay corrected (2015) tritium measurements is 6.2 tritium units (TU). This is somewhat smaller than the median value of all precipitation stations with 7.2 TU. This can be explained by the fact that in most cases in groundwater the median value has been reduced by decay

11. Effect of salinity on 2H/1H fractionation in lipids from continuous cultures of the coccolithophorid Emiliania huxleyi

Sachs, Julian P.; Maloney, Ashley E.; Gregersen, Josh; Paschall, Christopher

2016-09-01

Salinity and temperature dictate the buoyancy of seawater, and by extension, ocean circulation and heat transport. Yet there remain few widely applicable proxies for salinity with the precision necessary to infer all but the largest hydrographic variations in the past. In the last decade the hydrogen isotope composition (2H/1H or δ2H) of microalgal lipids has been shown to increase systematically with salinity, providing a foundation for its use as a paleosalinity proxy. Culture and field studies have indicated a wide range of sensitivities for this response, ranging from about 0.6-3.3‰ ppt-1 depending on the lipid, location and/or culturing conditions. Lacking in these studies has been the controlled conditions necessary to isolate the response to salinity while keeping all other growth parameters constant. Here we show that the hydrogen isotope composition of lipids in the marine coccolithophorid Emiliania huxleyi grown in chemostats increased by 1.6 ± 0.3‰ ppt-1 (p < 0.05) in eight individual alkenones and by 2.0 ± 0.1‰ ppt-1 (p < 0.05) in three individual fatty acids over the salinity range 20-42 ppt. Hydrogen isotope ratios of phytol and the sterol 24-methyl-cholest-5,22-dien-3β-ol (brassicasterol) also increased with salinity but correlations were weaker than for the acetogenic lipids. For eight individual alkenones, linear regression analyses of the fractionation factors on salinity yielded slopes of 1.2-2.2‰ ppt-1. This sensitivity of δ2Halkenone to salinity is 45-71% of that previously reported for E. huxleyi, which can be attributed to the fact that previous experiments were performed with batch cultures in which growth rates and other parameters differed between salinity treatments. The underlying cause of this response to salinity remains unknown, but may result from changes in (1) the proportion of lipid hydrogen derived from NADPH versus water, (2) the proportion of lipid hydrogen derived from NADPH from Photosystem I versus the oxidative

12. 40 CFR 721.9078 - 6-Methoxy-1H-benz[de]isoquinoline-2 [3H]-dione derivative (generic).

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 31 2011-07-01 2011-07-01 false 6-Methoxy-1H-benz isoquinoline-2 -dione derivative (generic). 721.9078 Section 721.9078 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) TOXIC SUBSTANCES CONTROL ACT SIGNIFICANT NEW USES OF CHEMICAL SUBSTANCES Significant New Uses for Specific Chemical Substances...

13. 40 CFR 721.9078 - 6-Methoxy-1H-benz[de]isoquinoline-2 [3H]-dione derivative (generic).

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 30 2010-07-01 2010-07-01 false 6-Methoxy-1H-benz isoquinoline-2 -dione derivative (generic). 721.9078 Section 721.9078 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) TOXIC SUBSTANCES CONTROL ACT SIGNIFICANT NEW USES OF CHEMICAL SUBSTANCES Significant New Uses for Specific Chemical Substances...

14. 40 CFR 721.9078 - 6-Methoxy-1H-benz[de]isoquinoline-2 [3H]-dione derivative (generic).

Code of Federal Regulations, 2013 CFR

2013-07-01

... 40 Protection of Environment 32 2013-07-01 2013-07-01 false 6-Methoxy-1H-benz isoquinoline-2 -dione derivative (generic). 721.9078 Section 721.9078 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) TOXIC SUBSTANCES CONTROL ACT SIGNIFICANT NEW USES OF CHEMICAL SUBSTANCES Significant New Uses for Specific Chemical Substances...

15. 40 CFR 721.9078 - 6-Methoxy-1H-benz[de]isoquinoline-2 [3H]-dione derivative (generic).

Code of Federal Regulations, 2012 CFR

2012-07-01

... 40 Protection of Environment 32 2012-07-01 2012-07-01 false 6-Methoxy-1H-benz isoquinoline-2 -dione derivative (generic). 721.9078 Section 721.9078 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) TOXIC SUBSTANCES CONTROL ACT SIGNIFICANT NEW USES OF CHEMICAL SUBSTANCES Significant New Uses for Specific Chemical Substances...

16. 40 CFR 721.9078 - 6-Methoxy-1H-benz[de]isoquinoline-2 [3H]-dione derivative (generic).

Code of Federal Regulations, 2014 CFR

2014-07-01

... 40 Protection of Environment 31 2014-07-01 2014-07-01 false 6-Methoxy-1H-benz isoquinoline-2 -dione derivative (generic). 721.9078 Section 721.9078 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) TOXIC SUBSTANCES CONTROL ACT SIGNIFICANT NEW USES OF CHEMICAL SUBSTANCES Significant New Uses for Specific Chemical Substances...

17. New pyrazole derivative 5-[1-(4-fluorophenyl)-1H-pyrazol-4-yl]-2H-tetrazole: synthesis and assessment of some biological activities.

PubMed

de Oliveira, Lanussy Porfiro; da Silva, Daiany Priscilla Bueno; Florentino, Iziara Ferreira; Fajemiroye, James Oluwagbamigbe; de Oliveira, Thiago Sardinha; Marcelino, Renato Ivan de Ávila; Pazini, Francine; Lião, Luciano Morais; Ghedini, Paulo César; de Moura, Soraia Santana; Valadares, Marize Campos; de Carvalho, Verônica Vale; Vaz, Boniek Gontijo; Menegatti, Ricardo; Costa, Elson Alves

2017-01-01

The molecular modification and synthesis of compounds is vital to discovering drugs with desirable pharmacological and toxicity profiles. In response to pyrazole compounds' antipyretic, analgesic, and anti-inflammatory effects, this study sought to evaluate the analgesic, anti-inflammatory, and vasorelaxant effects, as well as the mechanisms of action, of a new pyrazole derivative, 5-[1-(4-fluorophenyl)-1H-pyrazol-4-yl]-2H-tetrazole. During the acetic acid-induced abdominal writhing test, treatments with 5-[1-(4-fluorophenyl)-1H-pyrazol-4-yl]-2H-tetrazole reduced abdominal writhing, while during the formalin test, 5-[1-(4-fluorophenyl)-1H-pyrazol-4-yl]-2H-tetrazole reduced licking times in response to both neurogenic pain and inflammatory pain, all without demonstrating any antinociceptive effects, as revealed during the tail flick test. 5-[1-(4-fluorophenyl)-1H-pyrazol-4-yl]-2H-tetrazole also reduced carrageenan-induced paw edema and cell migration during the carrageenan-induced pleurisy test. As demonstrated by the model of the isolated organ, 5-[1-(4-fluorophenyl)-1H-pyrazol-4-yl]-2H-tetrazole exhibits a vasorelaxant effect attenuated by Nω-nitro-l-arginine methyl ester, 1H-[1,2,4]oxadiazolo[4,3-alpha]quinoxalin-1-one, tetraethylammonium or glibenclamide. 5-[1-(4-fluorophenyl)-1H-pyrazol-4-yl]-2H-tetrazole also blocked CaCl2 -induced contraction in a dose-dependent manner. Suggesting a safe toxicity profile, 5-[1-(4-fluorophenyl)-1H-pyrazol-4-yl]-2H-tetrazole reduced the viability of 3T3 cells at higher concentrations and was orally tolerated, despite signs of toxicity in doses of 2000 mg/kg. Lastly, the compounds' analgesic activity might be attributed to the involvement of the NO/cGMP pathway and K(+) channels observed in the vasorelaxant effect.

18. Heats of formation and thermodynamic functions for C2H, C3H, and C4H from 300 K to 6000 K

NASA Technical Reports Server (NTRS)

Saturno, A. F.

1982-01-01

A review of the energy level and heat of formation data for the species C2H, C3H, and C4H is given. The procedure for computing thermochemical data from partition function is also reviewed. Working expressions for approximate partition functions, free-energy function, enthalpy function, and heat capacity for a linear polyatomic species are presented.

19. 1-(4-Methyl­benz­yl)-1H-benzimidazol-2(3H)-one

PubMed Central

Belaziz, Dounia; Kandri Rodi, Youssef; Ouazzani Chahdi, Fouad; Essassi, El Mokhtar; Saadi, Mohamed; El Ammari, Lahcen

2013-01-01

In the title compound, C15H14N2O, the fused five- and six-membered ring system is essentially planar, the maximum deviation from the mean plane being 0.009 (1) Å. The benzimidazol-2(3H)-one residue is nearly perpendicular to the benzyl ring, forming a dihedral angle of 77.41 (6)°. In the crystal, inversion dimers are formed by pairs of N—H⋯O hydrogen bonds; these dimers are linked by weak C—H⋯O inter­actions into a two-dimensional array in the (102) plane. PMID:23476384

20. 4-Hydroxymethyl- and 4-methoxymethylfuro[2,3-h]quinolin-2(1H)-ones: synthesis and biological properties.

PubMed

2003-04-03

4-Hydroxymethyl-1,6,8-trimethylfuro[2,3-h]quinolin-2(1H)-one (HOFQ) was prepared by a new profitable way, which allowed to synthesize also 4-methoxymethyl-1,6,8-trimethylfuro[2,3-h]quinolin-2(1H)-one (MOFQ), and 4-hydroxymethyl-6,8-dimethylfuro[2,3-h]quinolin-2(1H)-one (HOHFQ). Some biological activities of the three compounds were studied in comparison with 8-MOP. In the dark, they inhibited topoisomerase II, leading to a moderate antiproliferative activity in mammalian cells. The antiproliferative activity was also tested upon UVA irradiation in mammalian cells: all compounds showed higher activity than 8-MOP, without mutagenicity and skin phototoxicity, with the best results for HOFQ. Photobinding to DNA was investigated, demonstrating a different sequence specificity for these furoquinolinones in comparison with furocoumarins. For all these features, HOFQ and the other analogues appeared very promising photochemotherapeutic agents, whose mechanism of action will be further investigated.

1. 2H/(1)H and (13)C/(12)C isotope ratios of trans-anethole using gas chromatography-isotope ratio mass spectrometry.

PubMed

Bilke, Steffi; Mosandl, Armin

2002-07-03

Authenticity assessment of trans-anethole is deduced from (2)H/(1)H and (13)C/(12)C isotope ratios, determined by gas chromatography-isotope ratio mass spectrometry (GC-IRMS). For that purpose, self-prepared anise and fennel oils, and synthetic and "natural" samples of trans-anethole, as well as commercially available anise and fennel oils have been investigated. Authenticity ranges of (2)H/(1)H and (13)C/(12)C isotope ratios of trans-anethole were defined. Scope and limitations of the applied online GC-IRMS techniques are discussed.

2. Secondary isotope effects in liquid chromatography behaviour of 2H and 3H labelled solutes and solvents.

PubMed

Valleix, Alain; Carrat, Sandrine; Caussignac, Céline; Léonce, Estelle; Tchapla, Alain

2006-05-26

water in mobile phases of the same composition (%, w/w) is compared. Independent of the nature of the organic modifier (methanol, acetonitrile or ethanol), the effect of replacing H2O with 2H2O in the mobile phase, is an increase in the retention factors and an improvement in the chromatographic resolution of isotopologue pairs. This increase in the resolution is not accompanied by a change in the chromatographic selectivity. The measurement of liquid-liquid extraction coefficients proves that the effect is mainly due to the modification of the phase ratio. In general the effect of 2H-labelled solvents (2H2O and C2H3CN) as mobile phase components, compared to their isotopically non-modified isomers, can be rationalized on the basis of their lower polarisabilities. Overall the use of perdeuterated rather than isotopically non-modified solvents as mobile phase components leads to the most efficient separation systems.

3. A general and efficient approach to 2H-indazoles and 1H-pyrazoles through copper-catalyzed intramolecular N-N bond formation under mild conditions.

PubMed

Hu, Jiantao; Cheng, Yongfeng; Yang, Yiqing; Rao, Yu

2011-09-28

A new efficient copper-catalyzed intramolecular amination reaction has been developed to readily synthesise a wide variety of multi-substituted 2H-indazole and 1H-pyrazole derivatives from easily accessible starting materials under mild conditions. A highly selective ligand for estrogen receptor β was prepared in three steps by employing this method.

4. A study of dipolar interactions and dynamic processes of water molecules in tendon by 1H and 2H homonuclear and heteronuclear multiple-quantum-filtered NMR spectroscopy.

PubMed

Eliav, U; Navon, G

1999-04-01

The effect of proton exchange on the measurement of 1H-1H, 1H-2H, and 2H-2H residual dipolar interactions in water molecules in bovine Achilles tendons was investigated using double-quantum-filtered (DQF) NMR and new pulse sequences based on heteronuclear and homonuclear multiple-quantum filtering (MQF). Derivation of theoretical expressions for these techniques allowed evaluation of the 1H-1H and 1H-2H residual dipolar interactions and the proton exchange rate at a temperature of 24 degrees C and above, where no dipolar splitting is evident. The values obtained for these parameters at 24 degrees C were 300 and 50 Hz and 3000 s-1, respectively. The results for the residual dipolar interactions were verified by repeating the above measurements at a temperature of 1.5 degrees C, where the spectra of the H2O molecules were well resolved, so that the 1H-1H dipolar interaction could be determined directly from the observed splitting. Analysis of the MQF experiments at 1.5 degrees C, where the proton exchange was in the intermediate regime for the 1H-2H dipolar interaction, confirmed the result obtained at 24 degrees C for this interaction. A strong dependence of the intensities of the MQF signals on the proton exchange rate, in the intermediate and the fast exchange regimes, was observed and theoretically interpreted. This leads to the conclusion that the MQF techniques are mostly useful for tissues where the residual dipolar interaction is not significantly smaller than the proton exchange rate. Dependence of the relaxation times and signal intensities of the MQF experiments on the orientation of the tendon with respect to the magnetic field was observed and analyzed. One of the results of the theoretical analysis is that, in the fast exchange regime, the signal decay rates in the MQF experiments as well as in the spin echo or CPMG pulse sequences (T2) depend on the orientation as the square of the second-rank Legendre polynomial.

5. Mass of {sup 11}Li from the {sup 1}H({sup 11}Li,{sup 9}Li){sup 3}H reaction

SciTech Connect

Roger, T.; Savajols, H.; Mittig, W.; Caamano, M.; Roussel-Chomaz, P.; Tanihata, I.; Alcorta, M.; Bandyopadhyay, D.; Bieri, R.; Buchmann, L.; Davids, B.; Galinski, N.; Howell, D.; Mills, W.; Mythili, S.; Openshaw, R.; Padilla-Rodal, E.; Ruprecht, G.; Sheffer, G.; Shotter, A. C.

2009-03-15

The mass of {sup 11}Li has been determined from Q-value measurements of the {sup 1}H({sup 11}Li,{sup 9}Li){sup 3}H reaction. The experiment was performed at TRIUMF laboratory with the GANIL active target MAYA. Energy-energy and angle-angle kinematics reconstruction give a Q value of 8.119(22) MeV for the reaction. The derived {sup 11}Li two-neutron separation energy is S{sub 2n}=363(22) keV.

6. The {sup 3}He(e,e'p){sup 2}H and {sup 4}He(e,e'p){sup 3}H reactions at high momentum transfer

SciTech Connect

Ford, William P.; Schiavilla, Rocco; Van Orden, J. W.

2014-03-01

We present updated calculations for observables in the processes {sup 3}He(e,e'p){sup 2}H, {sup 4}He(e,e'p){sup 3}H and {sup 4}He(e-vector, e'p-vector){sup 3}H. This update entails the implementation of improved nucleon-nucleon (NN) amplitudes to describe final state interactions (FSI) within a Glauber approximation and includes full spin-isospin dependence in the profile operator. In addition, an optical potential, which has also been updated since previous work, is utilized to treat FSI for the {sup 4}He(e,e'p){sup 3}H and {sup 4}He(e-vector, e'p-vector){sup 3}H reactions. The calculations are compared with experimental data and show good agreement between theory and experiment. Comparisons are made between the various approximations in the Glauber treatment, including model dependence due to the NN scattering amplitudes, rescattering contributions, and spin dependence. We also analyze the validity of the Glauber approximation at the kinematics the data is available, by comparing to the results obtained with the optical potential.

7. Synthesis and chemiluminescence of copolymers of 5-amino-8-vinyl-phthalazine-1,4(2H,3H)-dione with methyl methacrylate or styrene, and of alpha, omega-bis[5-amino-phthalazine-1,4(2H,3H)-dion-]8-yl alkanes [= alpha, omega-bis(6-luminyl) alkanes]: investigations on an intramolecular 'distance effect'.

PubMed

Gundermann, K D; Lieske, D; Haase, B; Hartmann-Azanza Baca, B

1987-09-01

Oligomers of 5-amino-8-vinyl-phthalazine-1,4(2H,3H)-dione exhibit about 0.05% of the chemiluminescence quantum yield of the corresponding 'monomer unit', i.e. 5-amino-8-ethyl-phthalazine-1,4(2H,3H)-dione which has a similar quantum yield to luminol. The quantum yields of copolymers of 5-amino-8-vinyl-phthalazine-1,4(2H,3H)-dione (1a) with methyl methacrylate or with styrene increase up to 1000-fold, relative to the quantum yield of oligomers of (1a). Thus the monomer units of methyl methacrylate or styrene appear to act as 'spacers' between the lumigenic groups. alpha, omega-Bis[(5-amino-phthalazine-1,4(2H,3H)-dion-)8-yl] alkanes show an analogue 'distance' effect: the chemiluminescence quantum yield increases with increasing alkane chain length. As the fluorescence of the corresponding amino phthalates (which are intermediates in the synthesis of the phthalazine diones) is only slightly influenced by the distance between the lumigenic groups it is suggested that a mainly chemical 'distance effect' is working here: the smaller the intramolecular distance between the hydrazide groups the more inhibition exists in respect of the oxidative reaction producing the luminol-type chemiluminescence.

8. Volumetric Properties of the Mixture 2-Chloroethanol C2H5ClO + C3H6O2 Methyl ethanoate (VMSD1511, LB4797_V)

Cibulka, I.; Fontaine, J.-C.; Sosnkowska-Kehiaian, K.; Kehiaian, H. V.

This document is part of Subvolume C 'Binary Liquid Systems of Nonelectrolytes III' of Volume 26 'Heats of Mixing, Vapor-Liquid Equilibrium, and Volumetric Properties of Mixtures and Solutions' of Landolt-Börnstein Group IV 'Physical Chemistry'. It contains the Chapter 'Volumetric Properties of the Mixture 2-Chloroethanol C2H5ClO + C3H6O2 Methyl ethanoate (VMSD1511, LB4797_V)' providing data from direct measurement of low-pressure thermodynamic speed of sound at variable mole fraction and constant temperature, in the single-phase region(s).

9. 1H and 2H NMR spin-lattice relaxation probing water: PEG molecular dynamics in solution.

PubMed

Clop, Eduardo M; Perillo, María A; Chattah, Ana K

2012-10-04

Nuclear magnetic resonance spin-lattice relaxation times (T(1)) measurements were performed in aqueous solutions of poly(ethylene glycol) (PEG) of 6000 Da molecular mass to study the dynamical relation between PEG and water molecules at different solute concentrations. (1)H-T(1) experiments were carried on at a low magnetic field in the time domain (20 MHz) and at a high field (400 MHz) to obtain spectral resolution. Two contributing components were identified in each proton system, PEG and water, presenting values of T(1) with very different orders of magnitude. The approximate matching between the shorter (1)H-T(1) values associated with water and PEG has lead us to conclude that there exists a network of interactions (hydrogen bonds) between the solute and the solvent, which results in the presence of an ordered and dehydrated structure of PEG folded or self-assembled in equilibrium with a more flexible monomer structure. Dynamic light scattering results were consistent with the formation of PEG aggregates, showing a mean size between 40 and 100 nm.

10. The Influence of Growth Rate on 2H/1H Fractionation in Continuous Cultures of the Coccolithophorid Emiliania huxleyi and the Diatom Thalassiosira pseudonana

PubMed Central

Sachs, Julian P.; Kawka, Orest E.

2015-01-01

The hydrogen isotope (2H/1H) ratio of lipids from phytoplankton is a powerful new tool for reconstructing hydroclimate variations in the geologic past from marine and lacustrine sediments. Water 2H/1H changes are reflected in lipid 2H/1H changes with R2 > 0.99, and salinity variations have been shown to cause about a 1‰ change in lipid δ2H values per unit (ppt) change in salinity. Less understood are the effects of growth rate, nutrient limitation and light on 2H/1H fractionation in phytoplankton. Here we present the first published study of growth rate effects on 2H/1H fractionation in the lipids of coccolithophorids grown in continuous cultures. Emiliania huxleyi was cultivated in steady state at four growth rates and the δ2H value of individual alkenones (C37:2, C37:3, C38:2, C38:3), fatty acids (C14:0, C16:0, C18:0), and 24-methyl cholest-5,22-dien-3β-ol (brassicasterol) were measured. 2H/1H fractionation increased in all lipids as growth rate increased by 24‰ to 79‰ (div d-1)-1. We attribute this response to a proportional increase in the fraction of NADPH from Photosystem I (PS1) of photosynthesis relative to NADPH from the cytosolic oxidative pentose phosphate (OPP) pathway in the synthesis of lipids as growth rate increases. A 3-endmember model is presented in which lipid hydrogen comes from NADPH produced in PS1, NADPH produced by OPP, and intracellular water. With published values or best estimates of the fractionation factors for these sources (αPS1 = 0.4, αOPP = 0.75, and αH2O = 0) and half of the hydrogen in a lipid derived from water the model indicates αlipid = 0.79. This value is within the range measured for alkenones (αalkenone = 0.77 to 0.81) and fatty acids (αFA = 0.75 to 0.82) in the chemostat cultures, but is greater than the range for brassicasterol (αbrassicasterol = 0.68 to 0.72). The latter is attributed to a greater proportion of hydrogen from NADPH relative to water in isoprenoid lipids. The model successfully explains

11. Histamine excites neurones in the human submucous plexus through activation of H1, H2, H3 and H4 receptors

PubMed Central

Breunig, Eva; Michel, Klaus; Zeller, Florian; Seidl, Stefan; v Weyhern, Claus Werner Hann; Schemann, Michael

2007-01-01

Histamine is a major mast cell mediator of immunoneural signalling in the gut and mast cells play a role in the pathophysiology of functional and inflammatory bowel diseases. Histamine receptors are therefore promising drug targets to treat gut disorders. We aimed to study the so far unknown effect of histamine on neural activity in the human enteric nervous system (ENS) and to identify the pharmacology of histamine response. We used fast imaging techniques in combination with the potentiometric dye di-8-ANEPPS to monitor directly membrane potential changes and thereby neuronal excitability in the human submucous plexus from surgical specimens of 110 patients (2137 neurones, 273 ganglia). Local microejection of histamine resulted in action potential discharge in 37% of neurones. This excitatory effect was mimicked by the H1 agonist HTMT-dimaleat, H2 agonist dimaprit, H3 agonist (R)-(−)-α-methylhistamine and H4 agonist 4-methylhistamine. The excitatory actions of the agonists were specifically and selectively blocked by the H1, H2, H3 or H4 receptor antagonists pyrilamine, ranitidine, clobenpropit or J1-[(5-chloro-1H-indol-2-yl)carbonyl]-4-methylpiperazine (JNJ 7777120), respectively. Clobenproprit reduced the excitatory response to histamine. Unlike in the guinea-pig ENS (R)-(−)-α-methylhistamine had no presynaptic actions in human submucous plexus. Application of agonists revealed receptor clustering which was as follows: 29% H1/H3, 27% H2, 20% H1/H2/H3, 10% H3, 7% H1/H2 and 7% H2/H3. Histamine excites human enteric neurones and this effect involves all four histamine receptors; most striking was the identification of an excitatory H3 mediated component and the discovery of H4 mediated neuronal excitation. These data may form the basis of identification of new targets to treat inflammatory and functional gut disorders. PMID:17627982

12. Preparation and studies of new crystals in the K3H(SO4)2-(NH4)3H(SO4)2-H2O system

Dmitricheva, E. V.; Makarova, I. P.; Grebenev, V. V.; Dolbinina, V. V.; Verin, I. A.

2014-05-01

To elucidate the effect of isomorphic substitution on the kinetics of phase transitions, single crystals of (K x (NH4)1- x ) m H n (SO4)( m + n)/2 · yH2O solid solutions are grown from the K3H(SO4)2-(NH4)3H(SO4)2-H2O system, whose end members are known to undergo superprotonic phase transitions of fundamentally different kinetics. The chemical composition of the single crystals grown is determined by energy dispersive X-ray microanalysis. The thermal and optical behavior of (K,NH4)9H7(SO4)8 · H2O single crystals is studied in the temperature range 295-420 K and the crystal structure at 295 K is determined. A comparison of the results of the studies with data for crystal K9H7(SO4)8 · H2O published earlier shows that the substitution of ammonium for potassium atoms lowers the temperature of the structural phase transition by 8 K.

13. DNA damage induced by 4,6,8,9-tetramethyl-2H-furo[2,3-h]quinolin-2-one, a new furocoumarin analog: photochemical mechanisms.

PubMed

Bordin, F; Baccichetti, F; Marzano, C; Carlassare, F; Miolo, G; Chilin, A; Guiotto, A

2000-03-01

Some photochemical and photobiological properties of 4,6,8,9-tetramethyl-2H-furo[2,3-h]quinolin-2-one (HFQ) were studied in comparison with its isomer 1,4,6,8-tetramethyl-2H-furo[2,3-h]quinolin-2-one (FQ) and 8-methoxypsoralen (8-MOP). The HFQ photobinds to DNA forming furan-side monoadducts (MAHFQ) that have molecular structure very similar to those of FQ (MAFQ). Unlike MA8-MOP and MAFQ, MAHFQ no longer photoreact. The HFQ, like FQ, produces moderate amounts of singlet oxygen but no superoxide anions. The HFQ and FQ induce numbers of DNA-protein cross-links (DPC), much more plentiful than those of 8-MOP (about two and seven times, respectively) but no interstrand cross-links. The mechanism of DPC formation was studied in vivo in mammalian cells by alkaline elution and in vitro using a new test mixing histones and DNA from calf thymus. The latter is a very useful technique for the double irradiation protocol. The DNA (or histones) are separately exposed to a first UVA dose in the presence of the sensitizer; then, after its unbound molecules have been removed, histones (or DNA) are added to assemble the chromatin-like complex that is irradiated again. According to in vitro and in vivo methods, DPC appear to be formed by FQ and 8-MOP by a biphotonic process that starts with monoadduct induction in DNA, followed by their conversion into DPC. In the resulting lesions, the sensitizer molecule forms a covalent bridge between the two macromolecules (DPC at length greater than zero). Instead, HFQ induces DPC by a monophotonic process; thus, HFQ is probably not a physical part of the bridge between DNA and proteins, which may be linked together directly, like DPC at zero length induced by UVC.

14. DNA damage induced by 4,6,8,9-tetramethyl-2H-furo[2,3-h]quinolin-2-one, a new furocoumarin analog: biological consequences.

PubMed

Marzano, C; Baccichetti, F; Carlassare, F; Chilin, A; Lora, S; Bordin, F

2000-03-01

4,6,8,9-Tetramethyl-2H-furo[2,3-h]quinolin-2-one (HFQ) and its isomer FQ (1,4,6,8-tetramethyl-2H-furo[2,3-h]quinolin-2-one) showed very strong antiproliferative activity in mammalian cells, about two times greater than 8-methoxypsoralen (8-MOP). Both compounds induced DNA-protein cross-links (DPC) but not interstrand cross-links. The FQ generated DPC in a biphotonic process, yielding a new kind of diadduct, whereas HFQ induced DPC by a monophotonic one, probably without its physical participation in the covalent bridge. These lesions gave different toxic responses. Sensitization of FQ led to extensive DNA fragmentation and to a number of chromosomal aberrations. Conversely, HFQ seemed to be completely inactive and 8-MOP gave intermediate results. A strict relationship between DPC formation and induction of chromosomal aberrations was observed. The HFQ did not induce light skin erythemas, whereas FQ was more phototoxic than 8-MOP, thus suggesting that FQ lesions, DPC in particular, may be implicated in skin phototoxicity. Ehrlich ascites cells, a transplantable mouse tumor, inactivated by furoquinolinone sensitization and injected into healthy mice, protected them from a successive challenge by viable tumor cells. This response appeared to be based on an immune mechanism. Comparable amounts of base substitution revertants were scored when testing furoquinolinones and 8-MOP in bacteria but no DPC were detected. This suggests that classic mutagenesis tests on bacteria are insufficient to give adequate information on furocoumarin genotoxicity. Given its features, HFQ can be regarded as an interesting new agent for psoralen plus UVA photochemotherapy and photopheresis.

15. Precision measurements of {sup 2}H(d,p){sup 3}H and {sup 2}H(d,n){sup 3}He total cross sections at Big Bang nucleosynthesis energies

SciTech Connect

Leonard, D.S.; Karwowski, H.J.; Brune, C.R.; Fisher, B.M.; Ludwig, E.J.

2006-04-15

Recent Wilkinson Microwave Anisotropy Probe (WMAP) measurements have determined the baryon density of the Universe {omega}{sub b} with a precision of about 4%. With {omega}{sub b} tightly constrained, comparisons of Big Bang nucleosynthesis (BBN) abundance predictions to primordial abundance observations can be made and used to test BBN models and/or to further constrain abundances of isotopes with weak observational limits. To push the limits and improve constraints on BBN models, uncertainties in key nuclear reaction rates must be minimized. To this end, we made new precise measurements of the {sup 2}H(d,p){sup 3}H and {sup 2}H(d,n){sup 3}He total cross sections at lab energies from 110 to 650 keV. A complete fit was performed in energy and angle to both angular distribution and normalization data for both reactions simultaneously. By including parameters for experimental variables in the fit, error correlations between detectors, reactions, and reaction energies were accurately tabulated by computational methods. With uncertainties around 2%{+-}1% scale error, these new measurements significantly improve on the existing data set. At relevant temperatures, by using the data of the present work, both reaction rates are found to be about 7% higher than those in the widely used NACRE (nuclear astrophysics compilation of reaction rates) database. These data will thus lead not only to reduced uncertainties, but also to modifications in the BBN abundance predictions.

16. The Davis-Beirut reaction: N1,N2-disubstituted-1H-indazolones via 1,6-electrophilic addition to 3-alkoxy-2H-indazoles.

PubMed

2011-06-17

A variety of electrophiles (anhydrides, acid chlorides, carbonochloridates, sulfonyl chlorides, and alkyl bromides) react with 3-methoxy-2H-indazole (1a), benzoxazin[3,2-b]indazole (1d), and oxazolino[3,2-b]indazole (1e) - substrates available by the Davis-Beirut reaction - to yield a diverse set of N(1),N(2)-disubstituted-1H-indazolones. With certain electrophiles, an AERORC (Addition of the Electrophile, Ring Opening, and Ring Closure) process on indazole 1d results in indazoloindazolone formation. An intriguing aspect of these N(1),N(2)-disubstituted-1H-indazolones is that they are poised for diversification through, for example, azide-alkyne cycloaddition chemistry reported here.

17. Synthesis and complete assignment of the 1H and 13C NMR spectra of 6-substituted and 2,6-disubstituted pyridazin-3(2H)-ones.

PubMed

Besada, Pedro; Costas, Tamara; Vila, Noemi; Chessa, Carla; Terán, Carmen

2011-07-01

Several pyridazin-3(2H)-one derivatives were synthesized starting from alkyl furans using oxidation with singlet oxygen to give 4-methoxy or 4-hydroxybutenolides, key intermediates of the synthetic strategy followed. For all pyridazinones reported, a complete assignment of the (1)H and (13)C NMR spectra using one- and two-dimensional NMR spectroscopic methods, which included NOE, DEPT, COSY, HSQC and HMBC experiments, was accomplished. Correlations between the chemical shifts of the heterocyclic ring atoms and substituents at N-2 and C-6 were analyzed.

18. DNA damage and biological effects induced by photosensitization with new N(1)-unsubstituted furo[2,3-h]quinolin-2(1H)-ones.

PubMed

2002-09-01

New furoquinolinones unsubstituted at the N(1) position were prepared and their photobiological activities were studied in comparison with 4,6,8,9-tetramethylfuro[2,3-h]quinolin-2(1H)-one (HFQ) and 8-MOP. The anti-proliferative activity of furoquinolinones 3a-f was tested upon UVA irradiation in mammalian cells, studying DNA synthesis and clonal growth capacity, and in micro-organisms, evaluating T2 infectivity. Almost all compounds appeared to be more active than 8-MOP, and free of any mutagenic activity and skin phototoxicity. Among them, compound 3b was the most effective one. Similarly to HFQ, compound 3b appeared to be very active also in DNA damaging, forming monoadducts and DPC(L=0), but no ISC and DPC(L>0), both responsible for furocoumarin genotoxicity and phototoxicity. Moreover, Ehrlich ascites cells, photoinactivated by the new furoquinolinone 3b and injected into recipient mice, proved to be capable of inducing protection against a successive challenge performed with the same tumor cells. For all these features, 3b seemed to be a new promising potential drug for PUVA therapy and photopheresis.

19. 1,4,8-trimethylfuro[2,3-H]quinolin-2(1H)-one, a new furocoumarin bioisoster.

PubMed

Marzano, Cristina; Chilin, Adriana; Baccichetti, Francarosa; Bettio, Frazia; Guiotto, Adriano; Miolo, Giorgia; Bordin, Franco

2004-05-01

1,4,8-Trimethylfuro[2,3-h]quinolin-2(1H)-one (compound 5a) is the most interesting derivative among some new furoquinolinones prepared with the aim of moderating the strong toxic effects of 1,4,6,8-tetramethyl derivative (FQ), a powerful potential drug for photomedicine. Compound 5a showed a photobiological activity lower than FQ, but considerable higher than 8-MOP, the furocoumarin used in clinical photomedicine; contrary to classic furocoumarins, 5a induced a strong inhibition of protein synthesis in mammalian cells. Genotoxicity and skin erythema induction, the main side effects of both FQ and 8-MOP photosensitization, are virtually absent with 5a. This behavior seems to be connected to its particular reaction mechanism: differently from furocoumarin derivatives, 5a induced low levels of DNA-protein and no inter-strands cross-links, but formed covalent RNA-protein linkages, lesions not observed with known furocoumarins. Moreover, compound 5a generated reactive oxygen species to a considerable extent. For these features, compound 5a appears to be a new photosensitizing agent whose special activity deserves to be deeply investigated.

20. Orthogonal hydrogen/halogen bonding in 1-(2-methoxyphenyl)-1H-imidazole-2(3H)-thione-I2 adduct: An experimental and theoretical study

El-Sheshtawy, Hamdy S.; Ibrahim, Mohamed M.; El-Mehasseb, Ibrahim; El-Kemary, Maged

2015-05-01

The molecular complex between 1-(2-methoxyphenyl)-1H-imidazole-2(3H)-thione (HmimOMe) and iodine (I2) was investigated. Single crystal of [(HmimOMe)radI2] adduct was grown by slow evaporation technique from chloroform at room temperature. Spectroscopic techniques such as FT-IR and Raman techniques, as well as elemental and thermal analysis were used to characterize the complex. The crystal structure shows that the formed adduct stabilized by two noncovalent interactions, namely, hydrogen bond (HB) and halogen bond (XB). Orthogonal HB/XB associated with iodine atom (I) was observed and fully characterized. The ability of iodine to behave as hydrogen bond acceptor and halogen bond donor was held responsible for the orthogonal HB/XB presence. In addition, the structure of HmimOMeradI2 was investigated theoretically using MP2/aug-cc-pVDZ level of theory. Natural bond orbital analysis (NBO) was used to investigate the molecular orbitals interactions and orbitals stabilization energies.

1. Study of the A(e,e'$\\pi^+$) Reaction on $^1$H, $^2$H, $^{12}$C, $^{27}$Al, $^{63}$Cu and $^{197}$Au

SciTech Connect

Qian, X; Clasie, B; Arrington, J; Asaturyan, R; Benmokhtar, F; Boeglin, W; Bosted, P; Bruell, A; Christy, M E; Chudakov, E; Dalton, M M; Daniel, A; Day, D; Dutta, D; El Fassi, L; Ent, R; Fenker, H C; Ferrer, J; Fomin, N; Gao, H; Garrow, K; Gaskell, D; Gray, C; Huber, G M; Jones, M K; Kalantarians, N; Keppel, C E; Kramer, K; Li, Y; Liang, Y; Lung, A F; Malace, S; Markowitz, P; Matsumura, A; Meekins, D G; Mertens, T; Miyoshi, T; Mkrtchyan, H; Monson, R; Navasardyan, T; Niculescu, G; Niculescu, I; Okayasu, Y; Opper, A K; Perdrisat, C; Punjabi, V; Rauf, A W; Rodriquez, V M; Rohe, D; Seely, J; Segbefia, E; Smith, G R; Sumihama, M; Tadevosyan, V; Tang, L; Villano, A; Vulcan, W F; Wesselmann, F R; Wood, S A; Yuan, L; Zheng, X

2010-05-01

Cross sections for the p($e,e'\\pi^{+}$)n process on $^1$H, $^2$H, $^{12}$C, $^{27}$Al, $^{63}$Cu and $^{197}$Au targets were measured at the Thomas Jefferson National Accelerator Facility (Jefferson Lab) in order to extract the nuclear transparencies. Data were taken for four-momentum transfers ranging from $Q^2$=1.1 to 4.8 GeV$^2$ for a fixed center of mass energy of $W$=2.14 GeV. The ratio of $\\sigma_L$ and $\\sigma_T$ was extracted from the measured cross sections for $^1$H, $^2$H, $^{12}$C and $^{63}$Cu targets at $Q^2$ = 2.15 and 4.0 GeV$^2$ allowing for additional studies of the reaction mechanism. The experimental setup and the analysis of the data are described in detail including systematic studies needed to obtain the results. The results for the nuclear transparency and the differential cross sections as a function of the pion momentum at the different values of $Q^2$ are presented. Global features of the data are discussed and the data are compared with the results of model calculations for the p($e,e'\\pi^{+}$)n reaction from nuclear targets.

2. Asymmetry in the N-inversion of heteroarene imines: pyrimidin-4(3H)-imine, pyridin-2(1H)-imine, and 1H-purine-6(9H)-imine.

PubMed

Glaser, Rainer; Yin, Jian; Miller, Stephanie

2010-02-19

The uncatalyzed, thermal N-inversion reactions were studied of pyrimidin-4(3H)-imine (PMI), pyridin-2(1H)-imine (PYI), and 1H-purine-6(9H)-imine (PUI). Relevant regions of the potential energy surfaces were explored with second-order Moller-Plesset perturbation theory (MP2(full)/6-31G(d)) and with coupled cluster theory (CCSD/6-31G(d), CCSD/6-31+G(d)). The thermochemistry of stationary structures was evaluated at the MP2 level and their energies also were computed at the levels CCSD(T)/6-311+G(d,p) and CCSD(T)/6-311+G(2df,2p) and with structures optimized at lower CCSD levels. The best estimates for the (E)-preference free enthalpies DeltaG(298)(Z vs. E) are 2.6 (PMI), 2.3 (PYI), and 6.0 (PUI) kcal/mol and for the free enthalpies of activation DeltaG(298)(Z --> E) they are 21.6 (PMI), 21.1 (PYI) and 19.7 (PUI) kcal/mol. Nonplanar N-inversion transition state (ITS) structures occur along enantiomeric reaction paths and stationary structures for in-plane N-inversion correspond to second-order saddle points (SOSP) on the potential energy surface. The deformation energy DeltaE(def) = E(SOSP) - E(ITS) is less than 0.5 kcal/mol for PMI and PUI, but it is as high as DeltaE(def) approximately = 2 kcal/mol for PYI. The detailed study of structures and electronic structures along the entire N-inversion path of the isomerization (Z)-PMI <==> (E)-PMI revealed a remarkable stabilization due to asymmetry in the ascent region from the (E)-isomer to ITS. Structures in this region of the potential energy surface allow best for additional bonding overlaps in the HOMO, and this amidine effect predicts lower N-inversion barriers in analogous imines with (Z)-preference energies. The discussion of the halogen-bonded aggregate PMI x ClCH(3) exemplifies that the asymmetry in N-inversion paths is retained and perhaps even enhanced in chlorinated solvents of low polarity.

3. Typing (A/B) and subtyping (H1/H3/H5) of influenza A viruses by multiplex real-time RT-PCR assays.

PubMed

Suwannakarn, Kamol; Payungporn, Sunchai; Chieochansin, Thaweesak; Samransamruajkit, Rujipat; Amonsin, Alongkorn; Songserm, Thaweesak; Chaisingh, Arunee; Chamnanpood, Pornchai; Chutinimitkul, Salin; Theamboonlers, Apiradee; Poovorawan, Yong

2008-09-01

In this study, a specific and sensitive one-step multiplex real-time RT-PCR was developed in two assays by using primers and a number of specific locked nucleic acid (LNA)-mediated TaqMan probes which increase the thermal stability of oligonucleotides. The first assay consisted of primers and probes specific to the matrix (M1) gene of influenza A virus, matrix (M1) gene of influenza B virus and GAPDH gene of host cells for typing of influenza virus and verification by an internal control, respectively. The other assay employed primers and probes specific to the hemagglutinin gene of H1, H3 and H5 subtypes in order to identify the three most prominent subtypes of influenza A capable of infecting humans. The specificity results did not produce any cross reactivity with other respiratory viruses or other subtypes of influenza A viruses (H2, H4 and H6-H15), indicating the high specificity of the primers and probes used. The sensitivity of the assays which depend on the type or subtype being detected was approximately 10 to 10(3)copies/microl that depended on the types or subtypes being detected. Furthermore, the assays demonstrated 100% concordance with 35 specimens infected with influenza A viruses and 34 specimens infected with other respiratory viruses, which were identified by direct nucleotide sequencing. In conclusion, the multiplex real-time RT-PCR assays have proven advantageous in terms of rapidity, specificity and sensitivity for human specimens and thus present a feasible and attractive method for large-scale detection aimed at controlling influenza outbreaks.

4. Towards understanding mechanistic linkages between climate and leaf wax biomarker 2H/1H: an elevational transect in the Wasatch Mountains, Utah

Berke, M. A.; Tipple, B. J.; Ehleringer, J.; Roden, J. S.

2012-12-01

Two significant challenges exist in establishing linkages between long-term biomarkers recorded in soils and sediments and often used in paleoclimatic reconstructions, and the much shorter timescale information obtained through other approaches, such as tree-ring analysis, often used in ecological reconstructions. The first of these challenges is to understand the mechanistic basis of how the biological proxy records environmental information. The second is understanding whether or not the phenological (temporal) production of a biomarker adequately integrates the climate on an annual or seasonal basis. Both aspects are of interest in climate reconstruction, but the limited temporal production of the biomarkers can result in different patterns. In order to address these questions, we analyzed the 2H/1H of long-chain n-alkanes from the leaves of Populus angustifolia (Cottonwood) along an elevational transect in Big Cottonwood Canyon near Salt Lake City, Utah (40°37'N, 111°48'W to 40°38'N, 111°40'W) that spanned a relatively short distance (13 km) but included a large 810 m elevation change (1433-2243 m). We compared these leaf wax observations to 2H/1H cellulose data sets along the same elevational gradient. Riparian P. angustifolia were selected because these trees exhibit a constant water source along the entire gradient. The elevational transect was collected during several time periods in 1997, 2011, and 2012 in order to evaluate both inter- and intra-annual variability with changes in environmental conditions over this interval. Our results suggest that there may be a mismatch between the seasonally integrating values of tree rings relative to the leaf wax biomarkers that tend to record only the beginning parts of a growing season.

5. Molecular dynamics of poly(L-lactide) biopolymer studied by wide-line solid-state 1H and 2H NMR spectroscopy.

PubMed

Nozirov, Farhod; Nazirov, Alovidin; Jurga, Stefan; Fu, Riqiang

2006-06-01

The molecular dynamics of poly(L-lactide) (PLLA) biopolymer was characterized through analyses of 1H and 2H NMR line-shapes and spin-lattice relaxation times at different temperatures. At low temperatures (e.g. 90 K), the methyl group rotation is dominant leading to a significant reduction in the proton second moment. Fast methyl group reorientation occurs at ca. 130 K. In additional to the fast methyl group rotation, hydroxyl groups start to reorient as the temperature increases further, eventually leading to the breakdown of the segments of the biopolymer chains above its glass transition temperature Tg of 323 K. The analyses of the 2H NMR line-shapes indicate that both the methyl and hydroxyl reorientations can be described by the so-called cone model, in which the former has three equilibrium positions with theta(C-D) = 70.5 degrees and phi = 120 degrees while the latter one exhibits two equilibrium positions with theta(O-D) = 78 degrees and phi = 180 degrees .

6. Cardiotonic agents. 7. Prodrug derivatives of 4-ethyl-1,3-dihydro- 5-[4-(2-methyl-1H-imidazol-1-yl)benzoyl]-2H-imidazol-2-one.

PubMed

Shaw, K J; Erhardt, P W; Hagedorn, A A; Pease, C A; Ingebretsen, W R; Wiggins, J R

1992-04-03

The cardiotonic agent 4-ethyl-1,3-dihydro-5-4-(2-methyl-1H-imidazol-1-yl)benzoyl]-2H- imidazol-2-one (1) was found to have low bioavailability when administered orally to rats and dogs. A series of N-acyl derivatives, an underutilized prodrug of acidic NH compounds, has been synthesized and tested for their ability to improve the oral bioavailability of 1. Reaction of the monosodium salt of 1 with various anhydrides afforded the N-1 monoacylimidazolones with surprisingly high regioselectivity. In addition to the prodrugs, acylation of 1 with propionic or phenylacetic anhydride led to the novel 3H-pyrrolo[1,2-c]imidazole-3,5(2H)-diones 6. The prodrugs showed a significant increase in the partition coefficients with a minor decrease in the aqueous solubility. The benzoyl derivative 4b exhibited the highest stability in both pH 1.5 and 7.4 buffer solutions. Further evaluation of 4b showed rapid conversion to 1 in canine plasma (t1/2 = 38 min), and human plasma (t1/2 = 10 min). Oral studies indicated that the bioavailability of 4b was increased to greater than 75% (compared to less than 20% for 1), and hemodynamic studies demonstrated that the selective inotropic profile of 1 was retained.

7. Tracing bacterial metabolism using multi-nuclear (1H, 2H, and 13C) Solid State NMR: Realizing an Idea Initiated by James Scott

Cody, G.; Fogel, M. L.; Jin, K.; Griffen, P.; Steele, A.; Wang, Y.

2011-12-01

Approximately 6 years ago, while at the Geophysical Laboratory, James Scott became interested in the application of Solid State Nuclear Magnetic Resonance Spectroscopy to study bacterial metabolism. As often happens, other experiments intervened and the NMR experiments were not pursued. We have revisited Jame's question and find that using a multi-nuclear approach (1H, 2H, and 13C Solid State NMR) on laboratory cell culture has some distinct advantages. Our experiments involved batch cultures of E. coli (MG1655) harvested at stationary phase. In all experiments the growth medium consisted of MOPS medium for enterobacteria, where the substrate is glucose. In one set of experiments, 10 % of the water was D2O; in another 10 % of the glucose was per-deuterated. The control experiment used both water and glucose at natural isotopic abundance. A kill control of dead E. coli immersed in pure D2O for an extended period exhibited no deuterium incorporation. In both deuterium enriched experiments, considerable incorporation of deuterium into E. coli's biomolecular constituents was detected via 2H Solid State NMR. In the case of the D2O enriched experiment, 58 % of the incorporated deuterium is observed in a sharp peak at a frequency of 0.31 ppm, consistent with D incorporation in the cell membrane lipids, the remainder is observed in a broad peak at a higher frequency (centered at 5.4 ppm, but spanning out to beyond 10 ppm) that is consistent with D incorporation into predominantly DNA and RNA. In the case of the D-glucose experiments, 61 % of the deuterium is observed in a sharp resonance peak at 0.34 ppm, also consistent with D incorporation into membrane lipids, the remainder of the D is observed at a broad resonance peak centered at 4.3 ppm, consistent with D enrichment in glycogen. Deuterium abundance in the E. coli cells grown in 10 % D2O is nearly 2X greater than that grown with 10 % D-glucose. Very subtle differences are observed in both the 1H and 13C solid

8. Simultaneous analysis of 17O/16O, 18O/16O and 2H/1H of gypsum hydration water by cavity ring‐down laser spectroscopy

PubMed Central

Mather, Ian; Rolfe, James; Evans, Nicholas P.; Herwartz, Daniel; Staubwasser, Michael; Hodell, David A.

2015-01-01

Rationale The recent development of cavity ring‐down laser spectroscopy (CRDS) instruments capable of measuring 17O‐excess in water has created new opportunities for studying the hydrologic cycle. Here we apply this new method to studying the triple oxygen (17O/16O, 18O/16O) and hydrogen (2H/1H) isotope ratios of gypsum hydration water (GHW), which can provide information about the conditions under which the mineral formed and subsequent post‐depositional interaction with other fluids. Methods We developed a semi‐automated procedure for extracting GHW by slowly heating the sample to 400°C in vacuo and cryogenically trapping the evolved water. The isotopic composition (δ17O, δ18O and δ2H values) of the GHW is subsequently measured by CRDS. The extraction apparatus allows the dehydration of five samples and one standard simultaneously, thereby increasing the long‐term precision and sample throughput compared with previous methods. The apparatus is also useful for distilling brines prior to isotopic analysis. A direct comparison is made between results of 17O‐excess in GHW obtained by CRDS and fluorination followed by isotope ratio mass spectrometry (IRMS) of O2. Results The long‐term analytical precision of our method of extraction and isotopic analysis of GHW by CRDS is ±0.07‰ for δ17O values, ±0.13‰ for δ18O values and ±0.49‰ for δ2H values (all ±1SD), and ±1.1‰ and ±8 per meg for the deuterium‐excess and 17O‐excess, respectively. Accurate measurement of the 17O‐excess values of GHW, of both synthetic and natural samples, requires the use of a micro‐combustion module (MCM). This accessory removes contaminants (VOCs, H2S, etc.) from the water vapour stream that interfere with the wavelengths used for spectroscopic measurement of water isotopologues. CRDS/MCM and IRMS methods yield similar isotopic results for the analysis of both synthetic and natural gypsum samples within analytical error of the two methods. Conclusions We

9. Detection and classification of hyperfine-shifted 1H, 2H, and 15N resonances of the Rieske ferredoxin component of toluene 4-monooxygenase.

PubMed

Xia, B; Pikus, J D; Xia, W; McClay, K; Steffan, R J; Chae, Y K; Westler, W M; Markley, J L; Fox, B G

1999-01-12

T4MOC is a 12.3 kDa soluble Rieske ferredoxin that is obligately required for electron transfer between the oxidoreductase and diiron hydroxylase components of toluene 4-monooxygenase from Pseudomonas mendocina KR1. Our preliminary 1H NMR studies of oxidized and reduced T4MOC [Markley, J. L., Xia, B., Chae, Y. K., Cheng, H., Westler, W. M., Pikus, J. D., and Fox, B. G. (1996) in Protein Structure Function Relationships (Zaidi, Z., and Smith, D., Eds.) pp 135-146, Plenum Press, London] revealed the presence of hyperfine-shifted 1H resonances whose short relaxation times made it impractical to use nuclear Overhauser effect (NOE) measurements for assignment purposes. We report here the use of selective isotopic labeling to analyze the hyperfine-shifted 1H, 2H, and 15N signals from T4MOC. Selective deuteration led to identification of signals from the four Hbeta atoms of cluster ligands C45 and C64 in the oxidized and reduced forms of T4MOC. In the reduced state, the Curie temperature dependence of the Hbeta protons corresponded to that predicted from the simple vector spin-coupling model for nuclei associated with the localized ferric site. The signal at 25.5 ppm in the 1H spectrum of reduced T4MOC was assigned on the basis of selective 2H labeling to the His Hepsilon1 atom of one of the cluster ligands (H47 or H67). This assignment was corroborated by a one bond 1H-13C correlation (at 25.39 ppm 1H and 136.11 ppm 13C) observed in spectra of [U-13C]T4MOC with a 1H-13C coupling constant of approximately 192 Hz. The carbon chemical shift and one bond coupling constant are those expected for 1Hepsilon1-13Cepsilon1 in the imidazolium ring of histidine and are inconsistent with values expected for cysteine 1Halpha-13Calpha. The His Hepsilon1 proton exhibited weak Curie temperature dependence from 283 to 303 K, contrary to the anti-Curie temperature dependence predicted from the spin coupling model for nuclei associated with the localized ferrous site. A 1H peak at -12.3 ppm

10. Results from Boiling Temperature Measurements for Saturated Solutions in the Systems NaCl + Ca(NO3)2 + H2O, NaNO3 + KNO3 + H2O, and NaCl + KNO3 + H2O, and Dry Out Temperatures for NaCl + NaNO3 + KNO3 + Ca(NO3)2 + H2O

SciTech Connect

Rard, J A

2005-11-29

Boiling temperature measurements have been made for saturated ternary solutions of NaCl + KNO{sub 3} + H{sub 2}O and NaNO{sub 3} + KNO{sub 3} + H{sub 2}O at three selected salt ratios and for NaCl + Ca(NO{sub 3}){sub 2} + H{sub 2}O over the full composition range. The maximum boiling temperature found for the NaCl + Ca(NO{sub 3}){sub 2} + H{sub 2}O system is 164.7 {+-} 0.6 C, and the composition is estimated to occur at x(Ca(NO{sub 3}){sub 2}) {approx} 0.25. Experiments were also performed for the five component NaCl + NaNO{sub 3} + KNO{sub 3} + Ca(NO{sub 3}){sub 2} + H{sub 2}O mixtures with the molar ratio of NaCl:NaNO{sub 3}:KNO{sub 3} held essentially constant at 1:0.9780:1.1468 as the solute mole fraction of Ca(NO{sub 3}){sub 2}, x(Ca(NO{sub 3}){sub 2}), was varied between 0 and 0.25. The NaCl + NaNO{sub 3} + KNO{sub 3} + Ca(NO{sub 3}){sub 2} + H{sub 2}O system forms low melting mixtures and thus boiling temperatures for saturated were not determined. Instead, the temperatures corresponding to the cessation of boiling (i.e., dry out temperatures) of these liquid mixtures were determined. These dry out temperatures range from {approx} 300 C when x(Ca(NO{sub 3}){sub 2}) = 0 to {ge} 400 C when x(Ca(NO{sub 3}){sub 2}) = 0.20 and 0.25. The investigated mixture compositions correspond to some of the major mineral assemblages that are predicted to control the deliquescence relative humidity of salts formed by leaching dust samples from the proposed nuclear repository at Yucca Mountain, Nevada.

11. Syntheses of 24R,25-dihydroxy-(6,19,19-3H)vitamin D3 and 24R,25-dihydroxy-(6,19,19-2H)vitamin D3

SciTech Connect

Yamada, S.; Shimizu, M.; Fukushima, K.; Niimura, K.; Maeda, Y. )

1989-08-01

24R,25-Dihydroxy-(6,19,19-3H)vitamin D3 with a specific activity of 54 Ci/mmol and 24R,25-dihydroxy-(6,19,19-2H)vitamin D3 with 2.6 deuterium atoms/mol were synthesized in four steps starting from 24R,25-Dihydroxyvitamin D3 via its sulfur dioxide adduct.

12. 21 CFR 73.3123 - 6-Ethoxy-2-(6-ethoxy-3-oxobenzo[b]thien-2(3H)-ylidene) benzo[b]thiophen-3 (2H)-one.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 21 Food and Drugs 1 2013-04-01 2013-04-01 false 6-Ethoxy-2-(6-ethoxy-3-oxobenzo thien-2(3H)-ylidene) benzo thiophen-3 (2H)-one. 73.3123 Section 73.3123 Food and Drugs FOOD AND DRUG ADMINISTRATION... to exceed the minimum reasonably required to accomplish the intended coloring effect....

13. 21 CFR 73.3123 - 6-Ethoxy-2-(6-ethoxy-3-oxobenzo[b]thien-2(3H)-ylidene) benzo[b]thiophen-3 (2H)-one.

Code of Federal Regulations, 2012 CFR

2012-04-01

... 21 Food and Drugs 1 2012-04-01 2012-04-01 false 6-Ethoxy-2-(6-ethoxy-3-oxobenzo thien-2(3H)-ylidene) benzo thiophen-3 (2H)-one. 73.3123 Section 73.3123 Food and Drugs FOOD AND DRUG ADMINISTRATION... to exceed the minimum reasonably required to accomplish the intended coloring effect....

14. Hydrogen isotope systematics in C3 and C4 saltmarsh plants: the importance of biochemical processes in controlling interspecies variation in n-alkane 2H/1H composition

Eley, Y.; Pedentchouk, N.

2013-12-01

Palaeohydrological studies have increasingly utilised the 2H/1H composition of leaf wax n-alkyl lipids to extract information from the geological record. Interpretation of the sedimentary biomarker δ2H signal, however, requires detailed understanding of the mechanisms controlling hydrogen isotope fractionation between source water and n-alkyl lipids (ɛl/w). The existence of large ranges in published n-alkyl δ2H and ɛl/w among modern plant species growing at a single location suggests that the lipid signal incorporated into the sedimentary record could be sensitive to relatively small-scale changes in vegetation assemblages. The mechanisms responsible for these interspecies differences are currently poorly constrained. Previous research has had limited success explaining n-alkyl δ2H by reference to physical processes controlling the movement of water inside/outside and within the leaf, while the relative importance of biochemical processes remains largely unexplored. This project aims to identify the mechanisms controlling interspecies variation in n-alkane 2H/1H among a range of C3 and C4 plants from a Norfolk saltmarsh in the UK. To distinguish between environmental, physical and biochemical controls, we conducted 2H/1H analysis of soil, xylem, and leaf waters and n-alkanes (i) across multiple sampling sites within the marsh, (ii) throughout the 2012 growth season, and (iii) at different times of the day. We also measured the 2H/1H of chloroplast phytol in 7 samples collected at the end of 2012. Leaf wax n-alkane δ2H varied among the sampled species by over 100‰ throughout the 2012 growth season. Environmental processes that could influence control source water 2H/1H did not fully account for this interspecies variation - soil water 2H/1H varied by only 35‰ with marsh sub-environment and exhibited site-specific seasonal shifts by no more than 31‰. Maximum interspecies variation in xylem water was 38‰, while leaf waters differed by only 29‰. We

15. Measurements of the Differential Cross Sections for the Elastic n-{sup 3}H and n-{sup 2}H Scattering at 14.1 MeV by Using an Inertial Confinement Fusion Facility

SciTech Connect

Frenje, J. A.; Li, C. K.; Seguin, F. H.; Casey, D. T.; Petrasso, R. D.; McNabb, D. P.; Navratil, P.; Quaglioni, S.; Sangster, T. C.; Glebov, V. Yu; Meyerhofer, D. D.

2011-09-16

For the first time the differential cross section for the elastic neutron-triton (n-{sup 3}H) and neutron-deuteron (n-{sup 2}H) scattering at 14.1 MeV has been measured by using an inertial confinement fusion facility. In these experiments, which were carried out by simultaneously measuring elastically scattered {sup 3}H and {sup 2}H ions from a deuterium-tritium gas-filled inertial confinement fusion capsule implosion, the differential cross section for the elastic n-{sup 3}H scattering was obtained with significantly higher accuracy than achieved in previous accelerator experiments. The results compare well with calculations that combine the resonating-group method with an ab initio no-core shell model, which demonstrate that recent advances in ab initio theory can provide an accurate description of light-ion reactions.

16. Homolytic, Heterolytic, Mesolytic - As You Like It: Steering the Cleavage of a HC(sp(3) )-C(sp(3) )H Bond in Bis(1H-2,1-benzazaborole) Derivatives.

PubMed

Hejda, Martin; Lyčka, Antonín; Mikysek, Tomáš; Jambor, Roman; Růžička, Aleš; Vinklárek, Jaromír; Wilfer, Claudia; Hoffmann, Alexander; Herres-Pawlis, Sonja; Dostál, Libor

2016-10-17

A set of (3,3')-bis(1-Ph-2-R-1H-2,1-benzazaborole) compounds, in which R=tBu (Bab-tBu)2 , R=Dipp (Bab-Dipp)2 or R=tBu and Dipp (Bab-Dipp)(Bab-tBu), was synthesized and fully characterized using (1) H, (11) B, (13) C, and (15) N NMR spectroscopy as well as single-crystal X-ray diffraction analysis. The central HC(sp(3) )-C(sp(3) )H bond with restricted rotation at the junction of both 1H-2,1-benzazaborole rings displayed an intriguing reactivity. It was demonstrated that this bond is easily mesolytically cleaved using alkali metals to form the respective aromatic 1Ph-2R-1H-2,1-benzazaborolyl anions M(+) (THF)n (Bab-tBu)(-) (M=Li, Na, K) and K(+) (THF)n (Bab-Dipp)(-) . Furthermore, the central HC(sp(3) )-C(sp(3) )H bond of bis(1H-2,1-benzazaborole)s is also homolytically cleaved either by heating or photochemical means, giving corresponding 1Ph-2R-1H-2,1-benzazaborolyl radicals (Bab-tBu)(.) and (Bab-Dipp)(.) , which rapidly self-terminate. Nevertheless, their formation was unambiguously established by NMR analysis of the reaction mixtures containing products of the self-termination of the radicals after heating or irradiation. (Bab-Dipp)(.) radical was also characterized using EPR spectroscopy. Importantly, it turned out that the essentially non-polarized HC(sp(3) )-C(sp(3) )H bond in (Bab-tBu)2 is also cleaved heterolytically with 2 equiv of MeLi, giving the mixture of Li(+) (SOL)n (Bab-tBu)(-) (SOL=THF or Et2 O) and lithium methyl-substituted borate complex Li(+) (SOL)n (Bab-tBu-Me)(-) in a diastereoselective fashion.

17. The reaction C sub 3 H sub 3 sup + + C sub 2 H sub 2 and the structural isomers of C sub 5 H sub 5 sup +

SciTech Connect

Feng, Jikang; Leszczynski, J.; Weiner, B.; Zerner, M.C. )

1989-06-21

The authors study here the isomers of C{sub 5}H{sub 5}{sup +} and possible reactions between C{sub 3}H{sub 3}{sup +} and acetylene that lead to the formation of C{sub 5}H{sub 5}{sup +} using quantum chemical means. They find very many stable C{sub 5}H{sub 5}{sup +} isomers, the most stable being the vinylcyclopropenylium cation. A pyramidal form is calculated to be quite stable as are distorted planar cyclopentadienyl cations. Nonplanar distortions in these five-membered rings, however, do not appear stable. With an eye toward identification of these species in sooting flames and in Fourier transform ion cyclotron resonance experiments, they report the calculated vibrational and electronic spectra of these species. They also study reactions of C{sub 3}H{sub 3}{sup +} with acetylene, attempting to model the nucleation step in the formation of soot. They find that the cyclic form of C{sub 3}H{sub 3}{sup +} does not react with acetylene without sizeable barrier, whereas the linear propargyl cation reacts with acetylene without barrier to form many different C{sub 5}H{sub 5+} tautomers, some of which are quite stable. They discuss these findings in conjunction with the results of experiments on these systems.

18. 6-Chloro-1-(3,5-dimethyl-phenyl-sulfon-yl)-1H-benzimidazol-2(3H)-one.

PubMed

Meneghetti, Fiorella; Bombieri, Gabriella; Logoteta, Patrizia; De Luca, Laura

2008-12-20

The title compound, C(15)H(13)ClN(2)O(3)S, is one of a series of N(1)-benzyl-1,3-dihydro-2H-benzimidazol-2-one derivatives, a new class of non-nucleoside HIV-1 reverse transcriptase inhibitors. The dihedral angle between the two pharmacophoric groups, the dimethyl-benzene ring and the benzimidazolone ring system, is 88 (1)°, giving a butterfly-like conformation to the mol-ecule. The mol-ecular packing is characterized by a bifurcated N-H⋯(O,O) hydrogen bond and short Cl⋯O contacts of 3.122 (2) Å. In addition, π-π stacking of the benzimidazolone rings is also present, with inter-planar separations of 3.95 (1) Å.

19. 6-Chloro-1-(3,5-dimethyl­phenyl­sulfon­yl)-1H-benzimidazol-2(3H)-one

PubMed Central

Meneghetti, Fiorella; Bombieri, Gabriella; Logoteta, Patrizia; De Luca, Laura

2009-01-01

The title compound, C15H13ClN2O3S, is one of a series of N 1-benzyl-1,3-dihydro-2H-benzimidazol-2-one derivatives, a new class of non-nucleoside HIV-1 reverse transcriptase inhibitors. The dihedral angle between the two pharmacophoric groups, the dimethyl­benzene ring and the benzimidazolone ring system, is 88 (1)°, giving a butterfly-like conformation to the mol­ecule. The mol­ecular packing is characterized by a bifurcated N—H⋯(O,O) hydrogen bond and short Cl⋯O contacts of 3.122 (2) Å. In addition, π–π stacking of the benzimidazolone rings is also present, with inter­planar separations of 3.95 (1) Å. PMID:21581616

20. Synthesis and biological evaluation of 2-fluoro and 3-trifluoromethyl-phenyl-piperazinylalkyl derivatives of 1H-imidazo[2,1-f]purine-2,4(3H,8H)-dione as potential antidepressant agents.

PubMed

Zagórska, Agnieszka; Bucki, Adam; Kołaczkowski, Marcin; Siwek, Agata; Głuch-Lutwin, Monika; Starowicz, Gabriela; Kazek, Grzegorz; Partyka, Anna; Wesołowska, Anna; Słoczyńska, Karolina; Pękala, Elżbieta; Pawłowski, Maciej

2016-01-01

A series of 2-fluoro and 3-trifluoromethylphenylpiperazinylalkyl derivatives of 1H-imidazo[2,1-f]purine-2,4(3H,8H)-dione (4-21) were synthesized and evaluated for their serotonin (5-HT1A/5-HT7) receptor affinity and phosphodiesterase (PDE4B and PDE10A) inhibitor activity. The study enabled the identification of potent 5-HT1A, 5-HT7 and mixed 5-HT1A/5-HT7 receptor ligands with weak inhibitory potencies for PDE4B and PDE10A. The tests have been completed with the determination of lipophilicity and metabolic stability using micellar electrokinetic chromatography (MEKC) system and human liver microsomes (HLM) model. In preliminary pharmacological in vivo studies, selected compound 8-(5-(4-(2-fluorophenyl)piperazin-1-yl)pentyl)-1,3,7-trimethyl-1H-imidazo[2,1-f]purine-2,4(3H,8H)-dione (9) behaved as a potential antidepressant in forced swim test (FST) in mice. Moreover, potency of antianxiety effects evoked by 9 (2.5 mg/kg) is greater than that of the reference anxiolytic drug, diazepam. Molecular modeling revealed that fluorinated arylpiperazinylalkyl derivatives of 1H-imidazo[2,1-f]purine-2,4(3H,8H)-dione have major significance for the provision of lead compounds for antidepressant and/or anxiolytic application.

1. Dynamics of [C{sub 3}H{sub 5}N{sub 2}]{sub 6}[Bi{sub 4}Br{sub 18}] by means of {sup 1}H NMR relaxometry and quadrupole relaxation enhancement

SciTech Connect

Masierak, W.; Florek-Wojciechowska, M.; Oglodek, I.; Jakubas, R.; Privalov, A. F.; Kresse, B.; Fujara, F.; Kruk, D.

2015-05-28

{sup 1}H spin-lattice field cycling relaxation dispersion experiments in the intermediate phase II of the solid [C{sub 3}H{sub 5}N{sub 2}]{sub 6}[Bi{sub 4}Br{sub 18}] are presented. Two motional processes have been identified from the {sup 1}H spin-lattice relaxation dispersion profiles and quantitatively described. It has been concluded that these processes are associated with anisotropic reorientations of the imidazolium ring, characterized by correlation times of the order of 10{sup −8} s-10{sup −9} s and of about 10{sup −5} s. Moreover, quadrupole relaxation enhancement (QRE) effects originating from slowly fluctuating {sup 1}H-{sup 14}N dipolar interactions have been observed. From the positions of the relaxation maxima, the quadrupole coupling parameters for the {sup 14}N nuclei in [C{sub 3}H{sub 5}N{sub 2}]{sub 6}[Bi{sub 4}Br{sub 18}] have been determined. The {sup 1}H-{sup 14}N relaxation contribution associated with the slow dynamics has been described in terms of a theory of QRE [Kruk et al., Solid State Nucl. Magn. Reson. 40, 114 (2011)] based on the stochastic Liouville equation. The shape of the QRE maxima (often referred to as “quadrupole peaks”) has been consistently reproduced for the correlation time describing the slow dynamics and the determined quadrupole coupling parameters.

2. Both water source and atmospheric water impact leaf wax n-alkane 2H/1H values of hydroponically grown angiosperm trees

Tipple, B. J.; Berke, M. A.; Hambach, B.; Roden, J. S.; Ehleringer, J. R.

2013-12-01

The extent to which both water source and leaf water 2H-enrichment affect the δ2H values of terrestrial plant leaf waxes is an area of active research as ecologists seek a mechanistic understanding of the environmental determinants of leaf wax isotope values before applying δ2H values of leaf waxes to reconstruct past hydrologic conditions. To elucidate the effects of both water source and atmospheric water vapor on δ2H values of leaf waxes for broad-leaved angiosperms, we analyzed hydrogen isotope ratios of high-molecular weight n-alkanes from two tree species that were grown throughout the spring and summer (five months) in a hydroponic system under controlled atmospheric conditions. Here, 12 subpopulations each of Populus fremontii and Betula occidentalis saplings were grown under one of six source different waters ranging in hydrogen isotope ratio values from -120 to +180 ‰ and under either 40 % or 75 % relative humidity conditions. We found n-alkane δ2H values of both species were linearly related to source water δ2H values with differences in slope associated with differing atmospheric humidity. A Craig-Gordon model was used to predict the δ2H values of leaf water and, by extension, n-alkane δ2H values under the range of growth conditions. The modeled leaf water values were found to be linearly related to observed n-alkane δ2H values with a statistically indistinguishable slope between the high and low humidity treatments. These leaf wax observations support a constant biosynthetic fractionation factor between evaporatively-enriched leaf water and n-alkanes for each species. However, we found the calculated biosynthetic fractionation between modeled leaf-water and n-alkane to be different between the two species. We submit that these dissimilarities were due to model inputs and not differences in the specific-species biochemistry. Nonetheless, these results are significant as they indicated that the δ2H value of atmospheric water vapor and

3. Predicting leaf wax n-alkane 2H/1H ratios: controlled water source and humidity experiments with hydroponically grown trees confirm predictions of Craig-Gordon model.

PubMed

Tipple, Brett J; Berke, Melissa A; Hambach, Bastian; Roden, John S; Ehleringer, James R

2015-06-01

The extent to which both water source and atmospheric humidity affect δ(2)H values of terrestrial plant leaf waxes will affect the interpretations of δ(2)H variation of leaf waxes as a proxy for hydrological conditions. To elucidate the effects of these parameters, we conducted a long-term experiment in which we grew two tree species, Populus fremontii and Betula occidentalis, hydroponically under combinations of six isotopically distinct waters and two different atmospheric humidities. We observed that leaf n-alkane δ(2)H values of both species were linearly related to source water δ(2)H values, but with slope differences associated with differing humidities. When a modified version of the Craig-Gordon model incorporating plant factors was used to predict the δ(2)H values of leaf water, all modelled leaf water values fit the same linear relationship with n-alkane δ(2)H values. These observations suggested a relatively constant biosynthetic fractionation factor between leaf water and n-alkanes. However, our calculations indicated a small difference in the biosynthetic fractionation factor between the two species, consistent with small differences calculated for species in other studies. At present, it remains unclear if these apparent interspecies differences in biosynthetic fractionation reflect species-specific biochemistry or a common biosynthetic fractionation factor with insufficient model parameterization.

4. Effects of distortion of the intercluster motion in {sup 2}H, {sup 3}He, {sup 3}H, {sup 6}Li, and {sup 9}Be on Trojan horse applications

SciTech Connect

Pizzone, R. G.; Spitaleri, C.; La Cognata, M.; Lamia, L.; Romano, S.; Mukhamedzhanov, A. M.; Blokhintsev, L. D.; Bertulani, C. A.; Irgaziev, B. F.

2009-08-15

Deuteron induced quasifree scattering and reactions have been extensively investigated in the past few decades as well as {sup 6}Li, {sup 3}H, {sup 3}He, and {sup 9}Be induced reactions. This was done not only for the investigation of nuclear structure and reaction mechanisms but also for important astrophysical applications (Trojan horse method). In particular the widths of the spectator momentum distributions in several nuclei, which have been used as Trojan horses, have been obtained as a function of the transferred momentum. Applications of Trojan horse method will also be discussed because the momentum distribution of the spectator particle inside the nucleus is a important input for this method. This gives hints on distortion effects at low energies important for nuclear astrophysics.

5. Isolation and structures of sulfonium salts derived from thioethers: [{o-C(6)H(4)(CH(2)SMe)(2)}H][NbF(6)] and [{[9]aneS(3)}H][NbF(6)].

PubMed

Jura, Marek; Levason, William; Reid, Gillian; Webster, Michael

2009-10-07

Two very unusual sulfonium salts, [{o-C(6)H(4)(CH(2)SMe)(2)}H][NbF(6)] and [{[9]aneS(3)}H][NbF(6)], obtained from reaction of the thioethers with NbF(5) in CH(2)Cl(2) solution, are reported and their structures described; the eight-coordinate tetrafluoro Nb(v) cation of the dithioether is obtained from the same reaction.

6. Low-energy SiC2H6+ and SiC3H9+ ion beam productions by the mass-selection of fragments produced from hexamethyldisilane for SiC film formations

Yoshimura, Satoru; Sugimoto, Satoshi; Murai, Kensuke; Kiuchi, Masato

2016-12-01

We have been attempting to produce low-energy ion beams from fragments produced through the decomposition of hexamethyldisilane (HMD) for silicon carbide (SiC) film formations. We mass-selected SiC2H6+ and SiC3H9+ ions from fragments produced from HMD, and finally produced low-energy SiC2H6+ and SiC3H9+ ion beams. The ion energy was approximately 100 eV. Then, the ion beams were irradiated to Si(100) substrates. The temperature of the Si substrate was 800°C during the ion irradiation. The X-ray diffraction and Raman spectroscopy of the substrates obtained following SiC2H6+ ion irradiation demonstrated the occurrence of 3C-SiC deposition. On the other hand, the film deposited by the irradiation of SiC3H9+ ions included diamond-like carbon in addition to 3C-SiC.

7. One-pot synthesis and antibacterial activities of novel 1H-pyridazino[1,2-a]indazole-1,6,9(2H,11H)-triones.

PubMed

Sayyafi, Maryam; Soorki, Ali Abolhasani; Bazgir, Ayoob

2008-09-01

Synthesis of novel 1H-pyridazino[1,2-a]indazole-1,6,9(2H,11H)-triones using one-pot, three components reaction of 1,2-dihydropyridazine-3,6-dione, dimedone and aldehydes under solvent-free conditions has been reported. These products were evaluated in vitro for their antibacterial activities.

8. Gas-phase reactions of the bare Th2+ and U2+ ions with small alkanes, CH4, C2H6, and C3H8: experimental and theoretical study of elementary organoactinide chemistry.

PubMed

Di Santo, Emanuela; Santos, Marta; Michelini, Maria C; Marçalo, Joaquim; Russo, Nino; Gibson, John K

2011-02-16

The gas-phase reactions of two dipositive actinide ions, Th(2+) and U(2+), with CH(4), C(2)H(6), and C(3)H(8) were studied by both experiment and theory. Fourier transform ion cyclotron resonance mass spectrometry was employed to study the bimolecular ion-molecule reactions; the potential energy profiles (PEPs) for the reactions, both observed and nonobserved, were computed by density functional theory (DFT). The experiments revealed that Th(2+) reacts with all three alkanes, including CH(4) to produce ThCH(2)(2+), whereas U(2+) reacts with C(2)H(6) and C(3)H(8), with different product distributions than for Th(2+). The comparative reactivities of Th(2+) and U(2+) toward CH(4) are well explained by the computed PEPs. The PEPs for the reactions with C(2)H(6) effectively rationalize the observed reaction products, ThC(2)H(2)(2+) and UC(2)H(4)(2+). For C(3)H(8) several reaction products were experimentally observed; these and additional potential reaction pathways were computed. The DFT results for the reactions with C(3)H(8) are consistent with the observed reactions and the different products observed for Th(2+) and U(2+); however, several exothermic products which emerge from energetically favorable PEPs were not experimentally observed. The comparison between experiment and theory reveals that DFT can effectively exclude unfavorable reaction pathways, due to energetic barriers and/or endothermic products, and can predict energetic differences in similar reaction pathways for different ions. However, and not surprisingly, a simple evaluation of the PEP features is insufficient to reliably exclude energetically favorable pathways. The computed PEPs, which all proceed by insertion, were used to evaluate the relationship between the energetics of the bare Th(2+) and U(2+) ions and the energies for C-H and C-C activation. It was found that the computed energetics for insertion are entirely consistent with the empirical model which relates insertion efficiency to the

9. Identification and correction of spectral contamination in 2H/1H and 18O/16O measured in leaf, stem, and soil water.

PubMed

Schultz, Natalie M; Griffis, Timothy J; Lee, Xuhui; Baker, John M

2011-11-15

Plant water extracts typically contain organic materials that may cause spectral interference when using isotope ratio infrared spectroscopy (IRIS), resulting in errors in the measured isotope ratios. Manufacturers of IRIS instruments have developed post-processing software to identify the degree of contamination in water samples, and potentially correct the isotope ratios of water with known contaminants. Here, the correction method proposed by an IRIS manufacturer, Los Gatos Research, Inc., was employed and the results were compared with those obtained from isotope ratio mass spectrometry (IRMS). Deionized water was spiked with methanol and ethanol to create correction curves for δ(18)O and δ(2)H. The contamination effects of different sample types (leaf, stem, soil) and different species from agricultural fields, grasslands, and forests were compared. The average corrections in leaf samples ranged from 0.35 to 15.73‰ for δ(2)H and 0.28 to 9.27‰ for δ(18)O. The average corrections in stem samples ranged from 1.17 to 13.70‰ for δ(2)H and 0.47 to 7.97‰ for δ(18)O. There was no contamination observed in soil water. Cleaning plant samples with activated charcoal had minimal effects on the degree of spectral contamination, reducing the corrections, by on average, 0.44‰ for δ(2)H and 0.25‰ for δ(18)O. The correction method eliminated the discrepancies between IRMS and IRIS for δ(18)O, and greatly reduced the discrepancies for δ(2)H. The mean differences in isotope ratios between IRMS and the corrected IRIS method were 0.18‰ for δ(18)O, and -3.39‰ for δ(2)H. The inability to create an ethanol correction curve for δ(2)H probably caused the larger discrepancies. We conclude that ethanol and methanol are the primary compounds causing interference in IRIS analyzers, and that each individual analyzer will probably require customized correction curves.

10. Quantum mechanical and spectroscopic (FT-IR, FT-Raman,1H,13C NMR, UV-Vis) studies, NBO, NLO, HOMO, LUMO and Fukui function analysis of 5-Methoxy-1H-benzo[d]imidazole-2(3H)-thione by DFT studies

Pandey, Manju; Muthu, S.; Nanje Gowda, N. M.

2017-02-01

Theoretical analysis of the molecular structure, spectroscopic (FT-IR, FT-Raman, 1H, 13C NMR, UV-Vis) studies, and thermodynamic characteristics of 5-Methoxy-1H-benzo[d]imidazole-2(3H)-thione (5MBIT) molecule were done by DFT/B3LYP using 6-311++G(d, p) basis set. Theoretical parameters were compared with experimental data. The dipole moment (μ), polarizability (Δα) and first order hyperpolarizability (β) of the molecule were calculated. Thermodynamic properties, HOMO and LUMO energies were determined. Global reactivity parameters and Fukui function of the 5MBIT molecule were predicted.

11. 1,3-Bis[3-(1,3-dioxoisoindolin-2-yl)prop­yl]-1H-anthra[1,2-d]imidazole-2,6,11(3H)-trione

PubMed Central

Afrakssou, Zahra; Rodi, Youssef Kandri; Capet, Frédéric; Essassi, El Mokhtar; Ng, Seik Weng

2011-01-01

The title compound, C37H26N4O7, is a 1H-anthra[2,1-d]imidazole-2,6,11(3H)-trione derivative having isoindolindionylpropyl substitutents attached to the imidazole N atoms. The anthraquinone fragment is buckled, the dihedral angle between the two benzene rings being 1.6 (1)°. The two isoindoline rings of the substituents of the imidazole ring are positioned on opposite sides of the five-membered ring; these are nearly mutually perpendicular [dihedral angle between isoindoline rings = 88.3 (1)°]. PMID:22091154

12. Toxicological study of the high-explosive formulation imidazo(4,5-d)imidazole-2,5(1H,3H)-dione, tetrahydro-1,4-dinitro

SciTech Connect

London, J.E.; Smith, D.M.

1984-02-01

The acute oral LD/sub 50/ values for the high-explosive formulation imidazo(4,5-d)imidazole-2,5(1H,3H)-dione, tetrahydro-1,4-dinitro (DINGU) for mice and rats are greater than 5 g/kg. According to classical guidelines, the mixture would be considered only slightly toxic or practically nontoxic in both species. Skin application studies in the rabbit with DINGU demonstrated that it was cutaneously nonirritating. This material was also nonirritating in rabbit eye application studies. The sensitization study in the guinea pig did not show DINGU to be deleterious in this regard.

13. Synthesis of New 2-Halo-2-(1H-tetrazol-5-yl)-2H-azirines via a Non-Classical Wittig Reaction.

PubMed

Cardoso, Ana L; Sousa, Carmo; Henriques, Marta S C; Paixão, José A; Pinho e Melo, Teresa M V D

2015-12-12

The synthesis and reactivity of tetrazol-5-yl-phosphorus ylides towards N-halosuccinimide/TMSN₃ reagent systems was explored, opening the way to new haloazidoalkenes bearing a tetrazol-5-yl substituent. These compounds were obtained as single isomers, except in one case. X-ray crystal structures were determined for three derivatives, establishing that the non-classical Wittig reaction leads to the selective synthesis of haloazidoalkenes with (Z)-configuration. The thermolysis of the haloazidoalkenes afforded new 2-halo-2-(tetrazol-5-yl)-2H-azirines in high yields. Thus, the reported synthetic methodologies gave access to important building blocks in organic synthesis, vinyl tetrazoles and 2-halo-2-(tetrazol-5-yl)-2H-azirine derivatives.

14. Control of open-framework structures through template⋯template interactions? Syntheses and structures of C 2H 7N 4OṡZnCl(HPO 4) and (C 2H 7N 4O) 2ṡZn 3(H 2O)(HPO 3) 4

Harrison, William T. A.

2006-03-01

The syntheses and structures of C 2H 7N 4OṡZnCl(HPO 4) and (C 2H 7N 4O) 2ṡZn 3(H 2O)(HPO 3) 4 are reported. Both phases arose in solution mediated reactions by way of the controlled, in situ, preparation of the cationic [C 2H 7N 4O] + guanylurea template by the slow hydrolysis of the neutral 2-cyanoguanidine starting material. C 2H 7N 4OṡZnCl(HPO 4) contains anionic [ZnCl(HPO 4)] - 6 3-topology polyhedral layers built up from vertex-sharing ZnO 3Cl and HPO 4 polyhedra. (C 2H 7N 4O) 2ṡZn 3(H 2O)(HPO 3) 4 is also layered and contains ZnO 4, ZnO 3(H 2O) and HPO 3 polyhedra sharing vertices by way of Zn sbnd O sbnd P bonds. In both structures, the guanylurea template participates in numerous template-to-framework and also template-to-template hydrogen bonds. Strikingly, the arrangement of template-to-template H bonds is different in the two structures, and also different to that seen earlier in C 2H 7N 4OṡZnPO 4. Crystal data: C 2H 7N 4OṡZnCl(HPO 4), M=299.91, monoclinic, Cc (No. 9), a=4.8823(2) Å, b=25.4781(11) Å, c=8.0335(4) Å, β=105.496(1)°, V=962.98(7) Å; Z=4. (C 2H 7N 4O) 2ṡZn 3(H 2O)(HPO 3) 4, M=740.27, triclinic, P1¯ (No. 2), a=9.0022(5) Å, b=9.5211(5) Å, c=13.4933(7) Å, α=94.986(1)°, β=94.111(1)°, γ=99.051(1)°, V=1133.51(1) Å; Z=2.

15. The neural inductive signal is transferred to ectoblast in 1-2 h but a continued contact with mesoblast for 2-3 h is essential for neuralization in the chick area pellucida.

PubMed

Joshi-Banka, D; Deshmukh, S; Modak, S P

2001-09-01

In the area pellucida of the chick gastrula, the Hensen's node (HN) graft must contact the competent ectoblast for at least 4 h to promote neural induction. When we removed the grafted HN after 1 to 3 h and replaced it by a non-inducing post nodal (PN) fragment, a 1-2 h contact with HN was found to be sufficient to promote neural induction. When HN graft was removed after 3 or 4 h and replaced by PN, the neural inductive response was substantially improved towards formation of archencephalic structures. Thus, our results indicate that neural induction takes place in two steps. In the first step, a contact with HN for 1-2 h is sufficient to transferthe inductive signal which is stabilized through a second step involving continued cell-cell contact with even non-inducing PN mesoblast.

16. Study of the tau- ---> pi- pi- pi+ pi0 pi0 nu/tau and tau- --> 3h- 2h+ nu/tau Decays Using the BaBar Detector

SciTech Connect

Sobie, R.; /Victoria U.

2005-06-21

The {tau}{sup -} {yields} {pi}{sup -}{pi}{sup -}{pi}{sup +}{pi}{sup 0}{pi}{sup 0}{nu}{sub {tau}} and {tau}{sup -} {yields} 3h{sup -} 2h{sup +} {nu}{sub {tau}} decays have been studied using the BABAR experiment at the PEP-II e{sup +}e{sup -} storage ring. Preliminary branching fractions are given for the {tau}{sup -} {yields} {pi}{sup -}{pi}{sup -}{pi}{sup +}{pi}{sup 0}{pi}{sup 0}{nu}{sub {tau}} and to the sub-channels {tau}{sup -} {yields} {eta}{pi}{sup -} {pi}{sup 0}{nu}{sub {tau}} and {tau}{sup -} {yields} {omega}(782){pi}{sup -}{pi}{sup 0}{nu}{sub {tau}}. A preliminary upper limit is given on the branching fraction for the {phi}(1020){pi}{sup -}{pi}{sup 0}{nu}{sub {tau}} mode. In addition a preliminary measurement of the branching fraction of the {tau}{sup -} {yields} 3h{sup -}2h{sup +} {nu}{sub {tau}} decay (h = {pi}, K) is presented.

17. Sauna, sweat and science - quantifying the proportion of condensation water versus sweat using a stable water isotope ((2)H/(1)H and (18)O/(16)O) tracer experiment.

PubMed

Zech, Michael; Bösel, Stefanie; Tuthorn, Mario; Benesch, Marianne; Dubbert, Maren; Cuntz, Matthias; Glaser, Bruno

2015-01-01

Most visitors of a sauna appreciate the heat pulse that is perceived when water is poured on the stones of a sauna stove. However, probably only few bathers are aware that this pleasant heat pulse is caused by latent heat being released onto our skin due to condensation of water vapour. In order to quantify the proportion of condensation water versus sweat to dripping water of test persons we conducted sauna experiments using isotopically labelled (δ(18)O and δ(2)H) thrown water as tracer. This allows differentiating between 'pure sweat' and 'condensation water'. Two ways of isotope mass balance calculations were applied and yielded similar results for both water isotopes. Accordingly, condensation contributed considerably to dripping water with mean proportions of 52 ± 12 and 54 ± 7% in a sauna experiment in winter semester 2011/12 and 30 ± 13 and 33 ± 6% in a sauna experiment in winter semester 2012/13, respectively, depending on the way of calculating the isotope mass balance. It can be concluded from the results of our dual isotope labelling sauna experiment that it is not all about sweat in the sauna.

18. On the Formation and Isomer Specific Detection of Propenal (C2H3CHO) and Cyclopropanone (c-C3H4O) in Interstellar Model Ices - A Combined FTIR and Reflectron Time-of-Flight Mass Spectroscopic Study

Abplanalp, Matthew J.; Borsuk, Aleca; Jones, Brant M.; Kaiser, Ralf I.

2015-11-01

The formation routes of two structural isomers—propenal (C2H3CHO) and cyclopropanone (c-C3H4O)—were investigated experimentally by exposing ices of astrophysical interest to energetic electrons at 5.5 K thus mimicking the interaction of ionizing radiation with interstellar ices in cold molecular clouds. The radiation-induced processing of these ices was monitored online and in situ via Fourier Transform Infrared spectroscopy and via temperature programmed desorption exploiting highly sensitive reflectron time-of-flight mass spectrometry coupled with single photon ionization in the post irradiation phase. To selectively probe which isomer(s) is/are formed, the photoionization experiments were conducted with 10.49 and 9.60 eV photons. Our studies provided compelling evidence on the formation of both isomers—propenal (C2H3CHO) and cyclopropanone (c-C3H4O)—in ethylene (C2H4)—carbon monoxide (CO) ices forming propenal and cyclopropanone at a ratio of (4.5 ± 0.9):1. Based on the extracted reaction pathways, the cyclopropanone molecule can be classified as a tracer of a low temperature non-equilibrium chemistry within interstellar ices involving most likely excited triplet states, whereas propenal can be formed at ultralow temperatures, but also during the annealing phase via non-equilibrium as well as thermal chemistry (radical recombination). Since propenal has been detected in the interstellar medium and our laboratory experiments demonstrate that both isomers originated from identical precursor molecules our study predicts that the hitherto elusive second isomer—cyclopropanone—should also be observable toward those astronomical sources such as Sgr B2(N) in which propenal has been detected.

19. 1,3-Bis(naphthalen-2-ylmeth­yl)-1H-anthra[1,2-d]imidazole-2,6,11(3H)-trione

PubMed Central

Afrakssou, Zahra; Rodi, Youssef Kandri; Capet, Frédéric; Essassi, El Mokhtar; Ng, Seik Weng

2011-01-01

The title compound, C37H24N2O3, is a 1H-anthra[2,1-d]imidazole-2,6,11(3H)-trione derivative having naphthyl­methyl substitutents attached to the imidazole N atoms. The anthraquinone part of the mol­ecule is somewhat folded along the the line connecting the carbonyl bonds. The dihedral angle between the two benzene rings is 7.8 (1)°. The two naphthyl systems of the substituents of the imidazole ring are positioned on the same side of the five-membered ring; these are approximately coplanar, the dihedral angle between the napthyl systems being 4.3 (2)°. PMID:22091155

20. Mechanism of action of 4-hydroxymethyl-1,6,8-trimethylfuro[2,3-h]quinolin-2(1H)-one, a very active angular furocoumarin-like sensitizer.

PubMed

Marzano, Cristina; Bettio, Frazia; Chilin, Adriana; Caffieri, Sergio; Reddi, Elena; Bordin, Franco

2005-01-01

The molecular structure of 1,4,6,8-tetramethylfuro[2,3-h]quinolin-2(1H)-one (FQ), a recent furocoumarin-like photosensitizer, has been modified with the aim of reducing its strong genotoxicity, by replacing the methyl group at 4 position with a hydroxymethyl one, and so obtaining 4-hydroxymethyl-1,6,8-trimethylfuro[2,3-h]quinolin-2(1H)-one (HOFQ). This modification gave rise to a strong reduction of lipophilicity and dark interaction with DNA. The formation of monoadducts (MA) was deeply affected, whereas the induction of bifunctional adducts between DNA and proteins (DPC(L>0)) was replaced by an efficient production of DNA-protein cross-links at zero length (DPC(L=0)), probably via guanine damage. Because of its angular molecular structure, HOFQ does not form interstrand cross-links (ISC): therefore, DPC(L=0) and MA represent the main lesions induced by HOFQ in DNA. In comparison with FQ (which induces MA and DPC(L>0)) and 8-methoxypsoralen (8-MOP) (MA, ISC, DPC(L>0)), HOFQ seems to be a more selective agent. In fact, contrary to FQ and 8-MOP, HOFQ, together with a noticeable antiproliferative activity, shows low levels of point mutations in bacteria and of clastogenic effects in mammalian cells. HOFQ is also an efficient apoptosis inducer, especially in comparison with 8-MOP, when tested at equitoxic experimental conditions; this property might be correlated with the complete HOFQ inability of inducing skin erythemas, a well-known side effect of classic furocoumarin photosensitization.

1. Enantioselective Synthesis of 3,4-Dihydro-1,2-oxazepin-5(2H)-ones and 2,3-Dihydropyridin-4(1H)-ones from β-Substituted β-Hydroxyaminoaldehydes

PubMed Central

2015-01-01

The synthesis of 3,4-dihydro-1,2-oxazepin-5(2H)-ones and 2,3-dihydropyridin-4(1H)-ones from β-substituted β-hydroxyaminoaldehydes is reported. The β-hydroxyaminoaldehydes were prepared by enantioselective organocatalytic 1,4-addition of N-tert-butyl (tert-butyldimethylsilyl)oxycarbamate to α,β-unsaturated aldehydes (MacMillan protocol). Alkyne addition to the aldehydes followed by alcohol oxidation furnished N-Boc O-TBS-protected β-aminoynones. Removal of the TBS protecting group initiated a 7-endo-dig cyclization to yield previously unknown 3,4-dihydro-1,2-oxazepin-5(2H)-ones. Reductive cleavage of the N–O bond of the oxazepinones and Boc-deprotection provided 2-substituted 2,3-dihydropyridin-4(1H)-ones via 6-endo-trig cyclization. 2,3-Dihydropyridin-4(1H)-ones are versatile intermediates that have been used for the synthesis of many alkaloids. The new protocol allows the synthesis of 3-dihydropyridin-4(1H)-ones carrying an array of substituents at C2 that cannot be prepared from commercial β-amino acids or by one-carbon homologation of proteinogenic amino acids. The use of readily available β-hydroxylaminoaldehydes expands the utility of our previously reported method to prepare 2,3-dihydropyridin-4(1H)-ones from β-amino acids as the source of diversity and chirality. A broad substrate scope is possible because β-aminoaldehydes can be prepared from α,β-unsaturated aldehydes by an enantioselective organocatalytic process. PMID:24785413

2. The crystal and molecular structure of N{sub 2}H{sub 5}[M(N{sub 2}H{sub 3}COO){sub 3}].H{sub 2}O (M-bar {l_brace}Co, Zn{r_brace}) isomorphic compounds-an X-ray crystallographic, vibrational spectroscopic and quantum-chemical study

SciTech Connect

Jesih, Adolf; Rahten, Anka; Benkic, Primoz; Skapin, Tomaz; Pejov, Ljupco . E-mail: ljupcop@iunona.pmf.ukim.edu.mk; Petrusevski, Vladimir M.

2004-12-01

A systematic study of N{sub 2}H{sub 5}[M(N{sub 2}H{sub 3}COO){sub 3}].H{sub 2}O (M-bar {l_brace}Co, Zn{r_brace}) type of compounds, which are typical model systems for transition metal complexes with {alpha}-amino acids (the latter are not obtainable in crystalline form), was carried out. The crystal structures of these compounds were solved by X-ray crystallographic methods. FTIR spectra at room and low temperature ({approx}100K) as well as Raman spectra at room temperature were recorded, and analyzed in details. Also, the geometries of the Zn(N{sub 2}H{sub 3}COO){sub 3}{sup -} and N{sub 2}H{sub 5}{sup +} species were fully optimized at ab initio HF and B3LYP/6-31+G(d,p) level of theory, and subsequent vibrational analyses were performed on the basis of which several important reassignments of the IR and Raman bands were proposed. In order to study the binding energetics and the ligand-cation charge-transfer interactions within the Zn(N{sub 2}H{sub 3}COO){sub 3}{sup -} complex, NBO analysis was carried out, employing the second-order perturbation theory analysis of the Fock matrix (i.e., its Kohn-Sham analog) within the NBO basis.

3. Ab initio studies on cyanoacetylenes of astrochemical interest: [Y(Ctbnd C)CN, Y dbnd C2H5, C3H7, C4H9, F, Cl, Br and CN

Kodi Ramanah, D.; Surajbali, P.; Rhyman, L.; Alswaidan, I. A.; Fun, H.-K.; Somanah, R.; Ramasami, P.

2016-01-01

Theoretical studies were performed on seven potential interstellar and circumstellar substituted cyanoacetylenes, Y(Ctbnd C)CN [Y = C2H5, C3H7, C4H9, F, Cl, Br and CN]. Geometry optimizations were carried out using the DFT/B3LYP, the CCSD and CCSD(T) levels of theory. The cc-pVTZ basis set was used for all atoms. Frequency computations were also carried out at the same level of theory as for the optimization to check the nature of the stationary points. The molecular and spectroscopic parameters of the cyanoacetylenes were computed. An analysis of these parameters is in line with the satisfactory performance of the B3LYP/cc-pVTZ level compared to the golden standard, the CCSD(T) level. The theoretical data reported in this work should facilitate future identifications of these cyanoacetylenes in extraterrestrial locations. Plausible mechanisms for the formation of these molecules have been proposed.

4. ACE-FTS Observation of a Young Biomass Burning Plume: First Reported Measurements of C2H4, C3H6O, H2CO and PAN by Infrared Occultation from Space

NASA Technical Reports Server (NTRS)

Coheur, Pierre-Francois; Herbin, Herve; Clerbaux, Cathy; Hurtmans, Daniel; Wespes, Catherine; Carleer, Michel; Turquety, Solene; Rinsland, Curtis P.; Remedios, John; Hauglustaine, Didier; Boone, Chris D.; Bernath, Peter F.

2007-01-01

In the course of our study of the upper tropospheric composition with the infrared 35 Atmospheric Chemistry Experiment Fourier Transform Spectrometer (ACE FTS), we 36 found an occultation sequence that on 8 October 2005, sampled a remarkable plume near the 37 east coast of Tanzania. Model simulations of the CO distribution in the Southern hemisphere 38 are performed for this period and they demonstrate that the emissions for this event originated 39 from a nearby forest fire, after which the plume was transported from the source region to the 40 upper troposphere. Taking advantage of the very high signal-to-noise ratio of the ACE FTS 41 spectra over a wide wavenumber range (750-4400 cm(exp -1), we present in-depth analyses of the 42 chemical composition of this plume in the middle and upper troposphere, focusing on the 43 measurements of weakly absorbing pollutants. For this specific biomass burning event, we 44 report simultaneous observations of an unprecedented number of organic species. 45 Measurements of C2H4 (ethene), C3H4 (propyne), H2CO (formaldehyde), C3H6O (acetone) 46 and CH3COO2NO2 (perxoxyacetylnitrate, abbreviated as PAN) are the first reported 47 detections using infrared occultation spectroscopy from satellites. Based on the lifetime of the 48 emitted species, we discuss the photochemical age of the plume and also report, whenever 49 possible, the enhancement ratios relative to CO.

5. Beam-energy dependence and updated test of the Trojan-horse nucleus invariance via a measurement of the 2H(d ,p )3H reaction at low energies

Li, Chengbo; Wen, Qungang; Tumino, A.; Fu, Yuanyong; Zhou, Jing; Zhou, Shuhua; Meng, Qiuying; Spitaleri, C.; Pizzone, R. G.; Lamia, L.

2017-03-01

The 2H(d ,p )3H bare nucleus astrophysical S (E ) factor has been measured indirectly at energies from about 500 keV down to several keV by means of the Trojan-horse method applied to the 2H(6Li,p t )4He quasifree reaction induced at 11 MeV. The obtained results are compared with direct data as well as with previous indirect investigation of the same binary reactions. It shows that the precision of S (E ) data in the low-energy range extracted via the same Trojan-horse nuclei [6Li=(d ⊕α )] becomes better when the incident energy of the virtual binary process decreases from high value down to the lower Gamow energy range, which near the zero-quasi-free-energy point. The very good agreement between data extracted from different Trojan-horse nuclei [6Li=(d ⊕α ) vs 3He=(d ⊕p )] gives a strong updated test for the independence of the binary indirect cross section on the chosen Trojan-horse nucleus at low energies.

6. Acid-base properties of xanthosine 5'-monophosphate (XMP) and of some related nucleobase derivatives in aqueous solution: micro acidity constant evaluations of the (N1)H versus the (N3)H deprotonation ambiguity.

PubMed

Massoud, Salah S; Corfù, Nicolas A; Griesser, Rolf; Sigel, Helmut

2004-10-11

The first acidity constant of fully protonated xanthosine 5'-monophosphate, that is, of H3(XMP)+, was estimated by means of a micro acidity constant scheme and the following three deprotonations of the H2(XMP)+/- (pKa=0.97), H(XMP)- (5.30), and XMP2- (6.45) species were determined by potentiometric pH titrations; further deprotonation of (XMP-H)3- is possible only with pKa>12. The most important results are that the xanthine residue is deprotonated before the P(O)2(OH)- group loses its final proton; that is, twofold negatively charged XMP carries one negative charge in the pyrimidine ring and one at the phosphate group. Micro acidity constant evaluations reveal that this latter mentioned species occurs with a formation degree of 88 %, whereas its tautomer with a neutral xanthine moiety and a PO3(2-) group is formed only to 12 %; this distinguishes XMP from its related nucleoside 5'-monophosphates, like guanosine 5'-monophosphate. At the physiological pH of about 7.5 mainly (XMP-H)3- exists. The question, which of the purine sites, (N1)H or (N3)H, is deprotonated in this species cannot be answered unequivocally, though it appears that the (N3)H site is more acidic. By application of several methylated xanthine species intrinsic micro acidity constants are calculated and it is shown that, for example, for 7-methylxanthine the N1-deprotonated tautomer occurs with a formation degree of about 5 %; a small but significant amount that, as is discussed, may possibly be enhanced by metal ion coordination to N7, which is known to occur preferably to this site.

7. Synthesis and molecular characterization of 5,5‧-((2,4-dichlorophenyl)methylene)bis(1,3-dimethylpyrimidine-2,4,6(1H,3H,5H)-trione)

Barakat, Assem; Al-Najjar, Hany J.; Al-Majid, Abdullah Mohammed; Soliman, Saied M.; Mabkhot, Yahia Nasser; Ghabbour, Hazem A.; Fun, Hoong-Kun

2015-03-01

A simple, economical, and green approach to the synthesis of 5,5‧-((2,4-dichlorophenyl)methylene)bis(1,3-dimethylpyrimidine-2,4,6(1H,3H,5H)-trione) 4 using a tandem Aldol condensation-Michael addition process in aqueous diethylamine medium was described. The 3D structure of the latter was confirmed by single-crystal X-ray structure determination. The molecular structure of the titled compound was calculated using DFT B3LYP/6-311G(d,p) method. The calculated geometric parameters are in good agreement with the experimental data obtained from our reported X-ay structure. The two pyrimidinetrione rings have C16 and C20 atoms deviated significantly from the ring plane. The electronic spectra of the studied compound have been calculated using the TD-DFT method. The longest wavelength band (257.8 nm, f = 0.0276) occurs due to H → L (86%) transition. The 1H and 13C NMR calculated chemical shifts using GIAO method showed good correlation with the experimental data. The molecular electrostatic potential (MEP) showed that the most reactive sites for electrophilic and nucleophilic attacks are the carbonyl oxygen (O5) and the H21 atoms, respectively. The NBO calculations were performed to predict the natural atomic charges at the different atomic sites and to study the different intramolecular charge transfer (ICT) interactions occurring in the studied system. Interestingly, there is some delocalization of electron densities from the occupied σ-type NBO of the C20sbnd H21 to the unoccupied π∗-NBO of the two adjacent carbonyl groups.

8. Synthesis, NMR, FT-IR, X-ray structural characterization, DFT analysis and isomerism aspects of 5-(2,6-dichlorobenzylidene)pyrimidine-2,4,6(1H,3H,5H)-trione

Barakat, Assem; Al-Najjar, Hany J.; Al-Majid, Abdullah Mohammed; Soliman, Saied M.; Mabkhot, Yahia Nasser; Shaik, Mohammed Rafi; Ghabbour, Hazem A.; Fun, Hoong-Kun

2015-08-01

The synthesis and spectral characterization of the 5-(2,6-dichlorobenzylidene)pyrimidine-2,4,6(1H,3H,5H)-trione;3 was reported. The solid state molecular structure of 3 was studied using X-ray crystallography. The relative stabilities of the seven possible isomers of 3 were calculated by DFT/B3LYP method using 6-311G(d,p) basis set. The calculated total energies and thermodynamic parameters were used to predict the relative stabilities of these isomers. The effect of solvent polarity on the relative stability of these isomers was studied at the same level of theory using PCM. It was found that the keto form, (T0), is the most stable isomer both in the gaseous state and solution. In solution, the calculated total energies of all isomers are decreased indicating that all isomers are stabilized by the solvent effect. The vibrational spectra of the most stable isomer, 3(T0) are calculated using the same level of theory and the results are compared with the experimentally measured FTIR spectra. Good correlation was obtained between the experimental and calculated vibrational frequencies (R2 = 0.9992). The electronic spectra of 3(T0) in gas phase as well as in solutions were calculated using the TD-DFT method. All the predicted electronic transitions showed very little spectral shifts and increase in the intensity of absorption due to solvent effect. Also the 1H- and 13C-NMR chemical shifts of the stable isomer were calculated and the results were correlated with the experimental data. Good correlations between the experimental and calculated chemical shifts were obtained.

9. Synthesis, NMR, FT-IR, X-ray structural characterization, DFT analysis and isomerism aspects of 5-(2,6-dichlorobenzylidene)pyrimidine-2,4,6(1H,3H,5H)-trione.

PubMed

Barakat, Assem; Al-Najjar, Hany J; Al-Majid, Abdullah Mohammed; Soliman, Saied M; Mabkhot, Yahia Nasser; Shaik, Mohammed Rafi; Ghabbour, Hazem A; Fun, Hoong-Kun

2015-08-05

The synthesis and spectral characterization of the 5-(2,6-dichlorobenzylidene)pyrimidine-2,4,6(1H,3H,5H)-trione;3 was reported. The solid state molecular structure of 3 was studied using X-ray crystallography. The relative stabilities of the seven possible isomers of 3 were calculated by DFT/B3LYP method using 6-311 G(d,p) basis set. The calculated total energies and thermodynamic parameters were used to predict the relative stabilities of these isomers. The effect of solvent polarity on the relative stability of these isomers was studied at the same level of theory using PCM. It was found that the keto form, (T0), is the most stable isomer both in the gaseous state and solution. In solution, the calculated total energies of all isomers are decreased indicating that all isomers are stabilized by the solvent effect. The vibrational spectra of the most stable isomer, 3(T0) are calculated using the same level of theory and the results are compared with the experimentally measured FTIR spectra. Good correlation was obtained between the experimental and calculated vibrational frequencies (R(2)=0.9992). The electronic spectra of 3(T0) in gas phase as well as in solutions were calculated using the TD-DFT method. All the predicted electronic transitions showed very little spectral shifts and increase in the intensity of absorption due to solvent effect. Also the (1)H- and (13)C-NMR chemical shifts of the stable isomer were calculated and the results were correlated with the experimental data. Good correlations between the experimental and calculated chemical shifts were obtained.

10. Corrosion inhibition of mild steel in 1M HCl by D-glucose derivatives of dihydropyrido [2,3-d:6,5-d′] dipyrimidine-2, 4, 6, 8(1H,3H, 5H,7H)-tetraone

PubMed Central

Verma, Chandrabhan; Quraishi, M. A.; Kluza, K.; Makowska-Janusik, M.; Olasunkanmi, Lukman O.; Ebenso, Eno E.

2017-01-01

D-glucose derivatives of dihydropyrido-[2,3-d:6,5-d′]-dipyrimidine-2, 4, 6, 8(1H,3H, 5H,7H)-tetraone (GPHs) have been synthesized and investigated as corrosion inhibitors for mild steel in 1M HCl solution using gravimetric, electrochemical, surface, quantum chemical calculations and Monte Carlo simulations methods. The order of inhibition efficiencies is GPH-3 > GPH-2 > GPH-1. The results further showed that the inhibitor molecules with electron releasing (-OH, -OCH3) substituents exhibit higher efficiency than the parent molecule without any substituents. Polarization study suggests that the studied compounds are mixed-type but exhibited predominantly cathodic inhibitive effect. The adsorption of these compounds on mild steel surface obeyed the Langmuir adsorption isotherm. SEM, EDX and AFM analyses were used to confirm the inhibitive actions of the molecules on mild steel surface. Quantum chemical (QC) calculations and Monte Carlo (MC) simulations studies were undertaken to further corroborate the experimental results. PMID:28317849

11. Synthesis, anticonvulsant, antioxidant and binding interaction of novel N-substituted methylquinazoline-2,4(1H, 3H)-dione derivatives to bovine serum albumin: A structure-activity relationship study

Prashanth, M. K.; Madaiah, M.; Revanasiddappa, H. D.; Veeresh, B.

2013-06-01

A novel class of N-substituted glycosmicine derivatives was synthesized, and their anticonvulsant, antioxidant activity and interaction with bovine serum albumin (BSA) were evaluated. The synthesized compounds 4a-j were examined for anticonvulsant activity by maximal electroshock induced seizures (MESs) test and their neurotoxic effects were determined by rotorod test in mice. The structure-activity relationships (SARs) of these compounds were also investigated. Compounds 4d, 4g, 4i and 4j were found to have good protective effect from seizure. The in vitro antioxidant activity was evaluated by 2,2-diphenyl-1-picrylhydrazyl (DPPH) and superoxide radical scavenging assay. The interaction between novel N-substituted methylquinazoline-2,4(1H, 3H)-dione (NMQ) and BSA was analyzed by fluorescence and ultraviolet spectroscopy at 304 K under simulative physiological conditions. BSA fluorescence quenched by NMQ is discussed according to the Stern-Volmer equation. The binding constant and binding sites of NMQ with BSA were calculated. According to Forster non-radiation energy transfer theory, the binding distance (r) between NMQ and BSA was calculated.

12. Molecular modeling studies of 4,5-dihydro-1H-pyrazolo[4,3-h] quinazoline derivatives as potent CDK2/Cyclin a inhibitors using 3D-QSAR and docking.

PubMed

Ai, Yong; Wang, Shao-Teng; Sun, Ping-Hua; Song, Fa-Jun

2010-09-28

CDK2/cyclin A has appeared as an attractive drug targets over the years with diverse therapeutic potentials. A computational strategy based on comparative molecular fields analysis (CoMFA) and comparative molecular similarity indices analysis (CoMSIA) followed by molecular docking studies were performed on a series of 4,5-dihydro-1H-pyrazolo[4,3-h]quinazoline derivatives as potent CDK2/cyclin A inhibitors. The CoMFA and CoMSIA models, using 38 molecules in the training set, gave r(2) (cv) values of 0.747 and 0.518 and r(2) values of 0.970 and 0.934, respectively. 3D contour maps generated by the CoMFA and CoMSIA models were used to identify the key structural requirements responsible for the biological activity. Molecular docking was applied to explore the binding mode between the ligands and the receptor. The information obtained from molecular modeling studies may be helpful to design novel inhibitors of CDK2/cyclin A with desired activity.

13. Synthesis of opioidmimetics, 3-[H-Dmt-NH(CH(2))(m)]-6-[H-Dmt-NH(CH(2))(n)]-2(1H)-pyrazinones, and studies on structure-activity relationships.

PubMed

Shiotani, Kimitaka; Miyazaki, Anna; Li, Tingyou; Tsuda, Yuko; Yokoi, Toshio; Ambo, Akihiro; Sasaki, Yusuke; Bryant, Sharon D; Jinsmaa, Yunden; Lazarus, Lawrence H; Okada, Yoshio

2007-11-01

Opioidmimetics containing 3-[H-Dmt-NH-(CH(2))(m)]-6-[H-Dmt-NH-(CH(2))(n)]-2(1H)-pyrazinone symmetric (m = n, 1-4) (1 - 4) and asymmetric (m, n = 1 - 4) aliphatic chains (5 - 16) were synthesized using dipeptidyl chloromethylketone intermediates. They had high mu-affinity (K(i)mu = 0.021 - 2.94 nM), delta-affinity (K(i)delta = 1.06 - 152.6 nM), and mu selectivity (K(i)delta/K(i)mu = 14 - 3,126). The opioidmimetics (1 - 16) exhibited mu agonism in proportion to their mu-receptor affinity. delta-Agonism was essentially lacking in the compounds except (4) and (16), and (1) and (2) indicated weak delta antagonism (pA(2) = 6.47 and 6.56, respectively). The data verify that a specific length of aliphatic linker is required between the Dmt pharmacophore and the pyrazinone ring to produce unique mu-opioid receptor ligands.

14. Corrosion inhibition of mild steel in 1M HCl by D-glucose derivatives of dihydropyrido [2,3-d:6,5-d‧] dipyrimidine-2, 4, 6, 8(1H,3H, 5H,7H)-tetraone

Verma, Chandrabhan; Quraishi, M. A.; Kluza, K.; Makowska-Janusik, M.; Olasunkanmi, Lukman O.; Ebenso, Eno E.

2017-03-01

D-glucose derivatives of dihydropyrido-[2,3-d:6,5-d‧]-dipyrimidine-2, 4, 6, 8(1H,3H, 5H,7H)-tetraone (GPHs) have been synthesized and investigated as corrosion inhibitors for mild steel in 1M HCl solution using gravimetric, electrochemical, surface, quantum chemical calculations and Monte Carlo simulations methods. The order of inhibition efficiencies is GPH-3 > GPH-2 > GPH-1. The results further showed that the inhibitor molecules with electron releasing (-OH, -OCH3) substituents exhibit higher efficiency than the parent molecule without any substituents. Polarization study suggests that the studied compounds are mixed-type but exhibited predominantly cathodic inhibitive effect. The adsorption of these compounds on mild steel surface obeyed the Langmuir adsorption isotherm. SEM, EDX and AFM analyses were used to confirm the inhibitive actions of the molecules on mild steel surface. Quantum chemical (QC) calculations and Monte Carlo (MC) simulations studies were undertaken to further corroborate the experimental results.

15. Capture and dissociation in the complex-forming CH(v = 0,1) + D2 → CHD + D, CD2 + H, CD + HD reactions and comparison with CH(v = 0,1) + H2.

PubMed

González, Miguel; Mayneris-Perxachs, Jordi; Saracibar, Amaia; Garcia, Ernesto

2011-08-14

Rate coefficients for the CH(v = 0,1) + D(2) reaction have been determined for all possible channels (T: 200-1200 K), using the quasiclassical trajectory method and a suitable treatment of the zero point energy. Calculations have also been performed on the CH(v = 1) + H(2) reaction and the CH(v = 1) + D(2) → CH(v = 0) + D(2) process. Most of the results can be understood considering the key role played by the deep minimum of the potential energy surface (PES), the barrierless character of the PES, the energy of the reaction channels, and the kinematics. The good agreement found between theory and experiment for the rate coefficients of the capture process of CH(v = 0) + D(2), the total reactivity of CH(v = 1) + D(2), H(2), as well as the good agreement observed for the related CH(v = 0) + H(2) system (capture and abstraction), gives confidence on the theoretical rate coefficients obtained for the capture processes of CH(v = 1) + D(2), H(2), the individual reactive processes of CH(v = 1) + D(2), H(2), the abstraction and abstraction-exchange reactions for CH(v = 0) + D(2), and the inelastic process mentioned above, for which there are no experimental data available, and that can be useful in combustion chemistry and astrochemistry.

16. Interaction Study of an Amorphous Solid Dispersion of Cyclosporin A in Poly-Alpha-Cyclodextrin with Model Membranes by (1)H-, (2)H-, (31)P-NMR and Electron Spin Resonance.

PubMed

Debouzy, Jean-Claude; Crouzier, David; Bourbon, Fréderic; Lahiani-Skiba, Malika; Skiba, Mohamed

2014-01-01

The properties of an amorphous solid dispersion of cyclosporine A (ASD) prepared with the copolymer alpha cyclodextrin (POLYA) and cyclosporine A (CYSP) were investigated by (1)H-NMR in solution and its membrane interactions were studied by (1)H-NMR in small unilamellar vesicles and by (31)P (2)H NMR in phospholipidic dispersions of DMPC (dimyristoylphosphatidylcholine) in comparison with those of POLYA and CYSP alone. (1)H-NMR chemical shift variations showed that CYSP really interacts with POLYA, with possible adduct formation, dispersion in the solid matrix of the POLYA, and also complex formation. A coarse approach to the latter mechanism was tested using the continuous variations method, indicating an apparent 1 : 1 stoichiometry. Calculations gave an apparent association constant of log Ka = 4.5. A study of the interactions with phospholipidic dispersions of DMPC showed that only limited interactions occurred at the polar head group level ((31)P). Conversely, by comparison with the expected chain rigidification induced by CYSP, POLYA induced an increase in the fluidity of the layer while ASD formation led to these effects almost being overcome at 298 K. At higher temperature, while the effect of CYSP seems to vanish, a resulting global increase in chain fluidity was found in the presence of ASD.

17. Identification of ligand efficient, fragment-like hits from an HTS library: structure-based virtual screening and docking investigations of 2H- and 3H-pyrazolo tautomers for Aurora kinase A selectivity.

PubMed

Sarvagalla, Sailu; Singh, Vivek Kumar; Ke, Yi-Yu; Shiao, Hui-Yi; Lin, Wen-Hsing; Hsieh, Hsing-Pang; Hsu, John T A; Coumar, Mohane Selvaraj

2015-01-01

Furanopyrimidine 1 (IC50 = 273 nM, LE = 0.36, LELP = 10.28) was recently identified by high-throughput screening (HTS) of an in-house library (125,000 compounds) as an Aurora kinase inhibitor. Structure-based hit optimization resulted in lead molecules with in vivo efficacy in a mouse tumour xenograft model, but no oral bioavailability. This is attributed to "molecular obesity", a common problem during hit to lead evolution during which degradation of important molecular properties such as molecular weight (MW) and lipophilicity occurs. This could be effectively tackled by the right choice of hit compounds for optimization. In this regard, ligand efficiency (LE) and ligand efficiency dependent lipophilicity (LELP) indices are more often used to choose fragment-like hits for optimization. To identify hits with appropriate LE, we used a MW cut-off <250, and pyrazole structure to filter HTS library. Next, structure-based virtual screening using software (Libdock and Glide) in the Aurora A crystal structure (PDB ID: 3E5A) was carried out, and the top scoring 18 compounds tested for Aurora A enzyme inhibition. This resulted in the identification of a novel tetrahydro-pyrazolo-isoquinoline hit 7 (IC50 = 852 nM, LE = 0.44, LELP = 8.36) with fragment-like properties suitable for further hit optimization. Moreover, hit 7 was found to be selective for Aurora A (Aurora B IC50 = 35,150 nM) and the possible reasons for selectivity investigated by docking two tautomeric forms (2H- and 3H-pyrazole) of 7 in Auroras A and B (PDB ID: 4AF3) crystal structures. This docking study shows that the major 3H-pyrazole tautomer of 7 binds in Aurora A stronger than in Aurora B.

18. Identification of ligand efficient, fragment-like hits from an HTS library: structure-based virtual screening and docking investigations of 2 H- and 3 H-pyrazolo tautomers for Aurora kinase A selectivity

Sarvagalla, Sailu; Singh, Vivek Kumar; Ke, Yi-Yu; Shiao, Hui-Yi; Lin, Wen-Hsing; Hsieh, Hsing-Pang; Hsu, John T. A.; Coumar, Mohane Selvaraj

2015-01-01

Furanopyrimidine 1 (IC50 = 273 nM, LE = 0.36, LELP = 10.28) was recently identified by high-throughput screening (HTS) of an in-house library (125,000 compounds) as an Aurora kinase inhibitor. Structure-based hit optimization resulted in lead molecules with in vivo efficacy in a mouse tumour xenograft model, but no oral bioavailability. This is attributed to "molecular obesity", a common problem during hit to lead evolution during which degradation of important molecular properties such as molecular weight (MW) and lipophilicity occurs. This could be effectively tackled by the right choice of hit compounds for optimization. In this regard, ligand efficiency (LE) and ligand efficiency dependent lipophilicity (LELP) indices are more often used to choose fragment-like hits for optimization. To identify hits with appropriate LE, we used a MW cut-off <250, and pyrazole structure to filter HTS library. Next, structure-based virtual screening using software (Libdock and Glide) in the Aurora A crystal structure (PDB ID: 3E5A) was carried out, and the top scoring 18 compounds tested for Aurora A enzyme inhibition. This resulted in the identification of a novel tetrahydro-pyrazolo-isoquinoline hit 7 (IC50 = 852 nM, LE = 0.44, LELP = 8.36) with fragment-like properties suitable for further hit optimization. Moreover, hit 7 was found to be selective for Aurora A (Aurora B IC50 = 35,150 nM) and the possible reasons for selectivity investigated by docking two tautomeric forms (2 H- and 3 H-pyrazole) of 7 in Auroras A and B (PDB ID: 4AF3) crystal structures. This docking study shows that the major 3 H-pyrazole tautomer of 7 binds in Aurora A stronger than in Aurora B.

19. Iridium complexes containing mesoionic C donors: selective C(sp3)-H versus C(sp2)-H bond activation, reactivity towards acids and bases, and catalytic oxidation of silanes and water.

PubMed

Petronilho, Ana; Woods, James A; Mueller-Bunz, Helge; Bernhard, Stefan; Albrecht, Martin

2014-11-24

Metalation of a C2-methylated pyridylimidazolium salt with [IrCp*Cl2]2 affords either an ylidic complex, resulting from C(sp(3))-H bond activation of the C2-bound CH3 group if the metalation is performed in the presence of a base, such as AgO2 or Na2CO3, or a mesoionic complex via cyclometalation and thermally induced heterocyclic C(sp(2))-H bond activation, if the reaction is performed in the absence of a base. Similar cyclometalation and complex formation via C(sp(2))-H bond activation is observed when the heterocyclic ligand precursor consists of the analogous pyridyltriazolium salt, that is, when the metal bonding at the C2 position is blocked by a nitrogen rather than a methyl substituent. Despite the strongly mesoionic character of both the imidazolylidene and the triazolylidene, the former reacts rapidly with D(+) and undergoes isotope exchange at the heterocyclic C5 position, whereas the triazolylidene ligand is stable and only undergoes H/D exchange under basic conditions, where the imidazolylidene is essentially unreactive. The high stability of the Ir-C bond in aqueous solution over a broad pH range was exploited in catalytic water oxidation and silane oxidation. The catalytic hydrosilylation of ketones proceeds with turnover frequencies as high as 6,000 h(-1) with both the imidazolylidene and the triazolylidene system, whereas water oxidation is enhanced by the stronger donor properties of the imidazol-4-ylidene ligands and is more than three times faster than with the triazolylidene analogue.

20. Characterization, molecular modeling and antimicrobial activity of metal complexes of tridentate Schiff base derived from 5-acetyl-4-hydroxy-2H-1,3-thiazine-2,6(3H)-dione and 2-aminophenol

Metal complexes of Ni(II), Co(II), Cd(II), VO(IV) and UO2(VI) as well as several Cu(II) salts, including Cl,NO3-,AcO,ClO4- and SO4-2 with a tridentate O2N donor Schiff base ligand (H2L), synthesized by condensation of 5-acetyl-4-hydroxy-2H-1,3-thiazine-2,6(3H)-dione with 2-aminophenol, were prepared and characterized on the basis of elemental analyses, spectral, magnetic, molar conductance and thermal gravimetric analysis. Square planar, tetrahedral and octahedral geometries have been assigned to the prepared complexes. Molecular parameters of the ligand and its metal complexes have been calculated and correlated with the experimental data, and the changes of bond lengths are linearly correlated with IR data. The antimicrobial activities of the synthesized compounds were tested in vitro against the sensitive organisms Staphylococcus aureus as Gram positive bacteria, Proteus vulgaris as Gram negative bacteria and Candida albicans as fungus strain, and the results are discussed.

1. Difference between ²JC2H3 and ²JC3H2 spin-spin couplings in heterocyclic five- and six-membered rings as a probe for studying σ-ring currents: a quantum chemical analysis.

PubMed

Contreras, Rubén H; dos Santos, Francisco P; Ducati, Lucas C; Tormena, Cláudio F

2010-12-01

Adequate analyses of canonical molecular orbitals (CMOs) can provide rather detailed information on the importance of different σ-Fermi contact (FC) coupling pathways (FC term transmitted through the σ-skeleton). Knowledge of the spatial distribution of CMOs is obtained by expanding them in terms of natural bond orbitals (NBOs). Their relative importance for transmitting the σ-FC contribution to a given spin-spin coupling constants (SSCCs) is estimated by resorting to the expression of the FC term given by the polarisation propagator formalism. In this way, it is possible to classify the effects affecting such couplings in two different ways: delocalisation interactions taking place in the neighbourhood of the coupling nuclei and 'round the ring' effects. The latter, associated with σ-ring currents, are observed to yield significant differences between the FC terms of (2)J(C2H3) and (2)J(C3H2) SSCCs which, consequently, are taken as probes to gauge the differences in σ-ring currents for the five-membered rings (furan, thiophene, selenophene and pyrrol) and also for the six-membered rings (benzene, pyridine, protonated pyridine and N-oxide pyridine) used in the present study.

2. Effects of oxygen tension and dextran-shelled/2H,3H-decafluoropentane-cored oxygen-loaded nanodroplets on secretion of gelatinases and their inhibitors in term human placenta.

PubMed

Prato, Mauro; Khadjavi, Amina; Magnetto, Chiara; Gulino, Giulia Rossana; Rolfo, Alessandro; Todros, Tullia; Cavalli, Roberta; Guiot, Caterina

2016-01-01

Matrix metalloproteinases (MMPs) and their endogenous inhibitors (TIMPs) need to be finely modulated in physiological processes. However, oxygen tension influences MMP/TIMP balances, potentially leading to pathology. Intriguingly, new 2H,3H-decafluoropentane-based oxygen-loaded nanodroplets (OLNDs) have proven effective in abrogating hypoxia-dependent dysregulation of MMP and TIMP secretion by single cell populations. This work explored the effects of different oxygen tensions and dextran-shelled OLNDs on MMP/TIMP production in an organized and multicellular tissue (term human placenta). Chorionic villous explants from normal third-trimester pregnancies were incubated with/without OLNDs in 3 or 20% O2. Explants cultured at higher oxygen tension released constitutive proMMP-2, proMMP-9, TIMP-1, and TIMP-2. Hypoxia significantly altered MMP-2/TIMP-2 and MMP-9/TIMP-1 ratios enhancing TIMP-2 and reducing proMMP-2, proMMP-9, and TIMP-1 levels. Intriguingly, OLNDs effectively counteracted the effects of low oxygen tension. Collectively, these data support OLND potential as innovative, nonconventional, and cost-effective tools to counteract hypoxia-dependent dysregulation of MMP/TIMP balances in human tissues.

3. Synthesis and biological evaluation of novel 5-alkyl-2-arylthio-6-((3,4-dihydroquinolin-1(2H)-yl)methyl)pyrimidin-4(3H)-ones as potent non-nucleoside HIV-1 reverse transcriptase inhibitors.

PubMed

Zhang, Jing; Zhan, Peng; Wu, Jingde; Li, Zhenyu; Jiang, Yan; Ge, Weiying; Pannecouque, Christophe; De Clercq, Erik; Liu, Xinyong

2011-07-15

A series of novel S-DABO analogues of 5-alkyl-2-arylthio-6-((3,4-dihydroquinolin-1(2H)-yl)methyl)pyrimidin-4(3H)-ones were synthesized and evaluated as inhibitors of human immunodeficiency virus type-1 (HIV-1). Among them, the most potent HIV-1 inhibitors were compounds 6c1,6c6, and 6b1 (EC(50)=0.24 ± 0.05, 0.38 ± 0.13, 0.39 ± 0.05 μM, respectively), which possess improved or similar HIV-1 inhibitory activity compared with nevirapine (NVP) (EC(50)=0.21 μM) and delavirdine (DLV) (EC(50)=0.32 μM). None of these compounds were active against HIV-2 replication. Furthermore, enzyme inhibitory assays were performed with selected derivatives against HIV-1 wtRT, confirming that the main target of these compounds is the HIV-1 RT and these new S-DABOs are acting as NNRTIs. The preliminary structure-activity relationship (SAR) of these new congeners is discussed briefly and rationalized by docking studies.

4. Molecular conformational analysis, reactivity, vibrational spectral analysis and molecular dynamics and docking studies of 6-chloro-5-isopropylpyrimidine-2,4(1H,3H)-dione, a potential precursor to bioactive agent

Al-Omary, Fatmah A. M.; Mary, Y. Sheena; Beegum, Shargina; Panicker, C. Yohannan; Al-Shehri, Mona M.; El-Emam, Ali A.; Armaković, Stevan; Armaković, Sanja J.; Van Alsenoy, C.

2017-01-01

FT-IR and FT-Raman spectra of 6-chloro-5-isopropylpyrimidine-2,4(1H,3H)-dione were recorded and analyzed. The vibrational wavenumbers were computed using DFT quantum chemical calculations and the data obtained from wavenumber calculations are used to assign the experimentally obtained bands. Potential energy distribution was done using GAR2PED software. The geometrical parameters of the title compound are in agreement with the XRD results. NBO analysis, frontier molecular orbital and first and second hyperpolarizability and molecular electrostatic potential results are also reported. The possible electrophile attacking sites of the title compound is identified using MEP surface plot study. Molecule sites prone to electrophilic attacks were identified using average local ionization energy surfaces, while further insight into the local reactivity properties of the title molecule has been gained by calculation of Fukui functions. Intra-molecular non-covalent interactions have been detected and visualized. Degradation properties based on autoxidation and hydrolysis have been investigated by calculation of bond dissociation energies and radial distribution functions, respectively. From the molecular docking study, the ligand binds at the active site of the substrate by weak non-covalent interactions and amino acids Leu89 forms alkyl interaction with the CH3 groups and Glu90 amino acid forms π-anion interaction with the pyrimidine ring and Thr369 and Ser366 amino acids form H-bond interaction with the Cdbnd O and NH group, respectively. From the conformational analysis, the calculated structures show that the C6C9C10 angle in the most stable form is about 8° smaller compared to the C8C9C10 angle, indicating a higher repulsive force between the (CH3)2HC- moiety and the chlorine atom due to the size of chlorine compared to oxygen atoms.

5. Synthesis, crystal structure and vibrational spectroscopic analysis of tetrakis(5-amino-1-H-1,2,4-triazol-4-ium) decachlorodibismuthate(III):[C2H5N4]4Bi2Cl10

Aloui, Z.; Ferretti, V.; Abid, S.; Lefebvre, F.; Rzaigui, M.; Nasr, C. Ben

2015-10-01

Physico-chemical properties of a new organic bismuthate(III), [C2H5N4]4Bi2Cl10 are discussed on the basis of X-ray crystal structure investigation. This compound crystallizes in the monoclinic space group C2/c, with a = 16.3622(3), b = 12.7941(2), c = 14.8178(2) Å, β = 98.5660(10)°, V = 3067.35(8) Å3 and Z = 4. The crystal structure consists of discrete binuclear [Bi2Cl10]4- anions and 3-amino-1-H-1,2,4-triazolium cations. The crystal packing is governed by strong Nsbnd H⋯N and weak Nsbnd H⋯Cl hydrogen bonds and Π-Π stacking interactions to form three-dimensional network. The 13C CP-MAS NMR spectrum is in agreement with the X-ray structure. The infrared study confirms the presence of the organic cation [C2H5N4]+. The vibrational absorption bands were identified by infrared spectroscopy and DFT calculations allowed their attribution.

6. Solute-fluid coupling and energy dissipation in supercritical fluids: 9-cyanoanthracene in C{sub 2}H{sub 6}, CO{sub 2}, and CF{sub 3}H

SciTech Connect

Rice, J.K.; Niemeyer, E.D.; Bright, F.V.

1996-05-16

We report on the coupling and dissipation of energy between a model fluorescent solute, 9-cyanoanthracene (9CA), and several supercritical fluid solvents. To this end, we have determined experimentally the fluorescence quantum yields and excited-state fluorescence lifetimes for dilute solutions of 9CA in supercritical C{sub 2}H{sub 6}, CO{sub 2}, and CF{sub 3}H. The 9CA quantum yield is substantially less than unity at lower fluid densities; it approaches unity only at the high-density, liquid-like region. The 9CA excited-state lifetime is also shortened significantly in the low-density region. The radiative (k{sub r}) and nonradiative (k{sub nr}) decay rates for 9CA are found to be strongly density dependent. In the low-density region, the nonradiative rate dominates; however, in the high-density region the 9CA de-excitation follows the radiative pathway. To yield agreement between the experimental k{sub r} data and the Strickler-Berg predictions, we require there to be changes in the total 9CA molar absorptivity with denisity. Recent experiments on anthracene and pyrene in supercritical CO{sub 2} demonstrate that the average solute molar absorptivity is indeed a function of fluid density. The strong density dependence of the nonradiative decay rate is interpreted in terms of an increase in fluid density leading to an increase in the energy gap ({Delta}E) between T{sub 2} and S{sub 1} states. 69 refs., 10 figs., 1 tab.

7. Spectroscopic and structural studies of new mononucleating tetradentate Schiff base metal chelates derived from 5-acetyl-4-hydroxy-2H-1,3-thiazine-2,6(3H)-dione and 1,3-diaminopropane

Adly, Omima M. I.; Taha, Ali; Fahmy, Shery A.

2015-08-01

Metal complexes with the general formula Some newly transition metal complexes, [ML(H2O)x(NO3)y], x = 1-2 and y = 0-1, [M = Cr(III), Fe(III), Co(II), Ni(II), Cu(II), Ce(III), Cd(II), Zn(II) or UO2(VI)], L= of the Schiff base (H2L) derived from the reaction of 5-acetyl-4-hydroxy-2H-1,3-thiazine-2,6(3H)-dione with 1,3-diaminopropane have been prepared and characterized by physical, spectral and analytical data. The structure of the Schiff - base acts as dibasic tetradentate N2O2 for the complexation reaction with Cr(III), Fe(III), Co(II), Cu(II), Ni(II), Ce(III), Cd(II), and UO2(II) ions via phenolates oxygen and nitrogen of azomethine groups. Based on spectral data and magnetic moments, an octahedral geometry may be proposed for the synthesized complexes except cerium(III) complex which has pentagonal bipyramidal arrangement. The low values of the molar conductance indicate non-electrolyte nature of complexes, while 1:1 electrolyte for cerium(III)- and chromium(III)-complexes. The Coats-Redfern equation was used to calculate the kinetic and thermodynamic parameters for the different thermal decomposition steps of some complexes. All the synthesized compounds were tested for in vitro antibacterial activity against some Gram-positive and Gram-negative bacteria, yeast and fungus. Molecular structure of the Schiff base ligand and its complexes were optimized for the proposed structures on the basis of semiempirical PM3 method.

8. Difference between 2 h and 3 h 75 g glucose tolerance test in the diagnosis of gestational diabetes mellitus (GDM): results from a national survey on prevalence of GDM.

PubMed

Gao, Xue-Lian; Wei, Yu-Mei; Yang, Hui-Xia; Xu, Xian-Ming; Fan, Ling; He, Jing; Liu, Ning; Zhao, San-Cun; Hu, Ya-Li; Yang, Zi; Zhang, Yun-Ping; Liu, Xing-Hui; Chen, Xu; Zhang, Jian-Ping; Gou, Wen-Li; Xiao, Mei; Wu, Hai-Rong; Zhang, Mei-Hua

2010-09-01

The possibility of the 2 h oral glucose tolerance test (OGTT) as an alternative to the 3 h OGTT was investigated based on data from a national survey on pregnancy-associated diabetes. Data were retrieved from 4179 pregnant women who had OGTT performed after an abnormal 50 g glucose challenge test (GCT). All of the 4 glucose levels during their OGTT were collected and analyzed. According to American Diabetes Association (ADA) gestational diabetes mellitus (GDM) diagnostic criteria, among the 4179 pregnant women who required OGTT, 3429 (82.1%) were normal and 750 (17.9%) were diagnosed as GDM. If the 3rd h glucose levels were omitted from OGTT, 79 cases of GDM (10.5%) would be overlooked. No trend was shown where women with more risk factors were more likely to be overlooked if the 3rd h test was omitted (χ2 for trend=0.038, P>0.05). No significant differences were found in the rate of cesarean section (CS), preterm births or macrosomia between the 79 cases and those with normal OGTT results and in the gestational weeks when OGTT was performed. It shows that in order to diagnose one woman with GDM, another 52 pregnant women would have an innocent 3rd h glucose test. Omission of the 3rd h glucose test in OGTT might be reasonable due to its convenience, better compliance and a small number of possibly miss-diagnosed cases, and their pregnancy outcomes have no significant difference from those of normal pregnant women.

9. Crystal structure of 3-{1-[(1-allyl-1H-indazol-6-yl)amino]­ethyl­idene}-6-methyl-2H-pyran-2,4(3H)-dione

PubMed Central

El Ghozlani, Mohamed; Rakib, El Mostapha; Gamouh, Ahmed; Saadi, Mohamed; El Ammari, Lahcen

2014-01-01

In the title compound, C18H17N3O3, the dihedral angle between the planes of the indazole ring system [maximum deviation = 0.012 (1) Å] and the pyran-2,4-dione ring is 54.03 (6)°. An intra­molecular N—H⋯O hydrogen bond closes an S(6) ring. The same H atom also participates in an inter­molecular N—H⋯O hydrogen bond, which generates an inversion dimer. The dimers are linked by weak C—H⋯O contacts, thereby forming a three-dimensional network. PMID:25553030

10. Layered hybrid organic-inorganic Co(II) alkylphosphonates. Synthesis, crystal structure and magnetism of the first two members of the series: Co[(CH{sub 3}PO{sub 3})(H{sub 2}O)] and Co[(C{sub 2}H{sub 5}PO{sub 3})(H{sub 2}O)

SciTech Connect

Bauer, Elvira M.; Bellitto, Carlo . E-mail: carlo.bellitto@ism.cnr.it; Colapietro, Marcello . E-mail: m.colapietro@caspur.it; Ibrahim, Said A.; Mahmoud, Mohamed R.; Portalone, Gustavo; Righini, Guido

2006-02-15

Co[(CH{sub 3}PO{sub 3})(H{sub 2}O)] (1) and Co[(C{sub 2}H{sub 5}PO{sub 3})(H{sub 2}O)] (2) were prepared by the hydrothermal method and isolated as blue-violet platelet crystals. They were characterized by X-ray diffraction, FT-IR, TGA-DSC techniques and their magnetic properties studied by a dc-SQUID magnetometer. Compound (1) shows an hybrid layered structure, made of alternating inorganic and organic layers along the a-direction of the unit cell. The inorganic layers contain Co(II) ions six-coordinated by five phosphonate oxygen atoms and one from the water molecule. These layers are separated by bi-layers of methyl groups and van der Waals contacts are established between them. In compound (2), the layered hybrid structure is rather similar to that described for compound (1), but the alternation of the inorganic and organic layers is along the b-direction of the unit cell. The magnetic behavior of (1) and (2) as function of temperature and magnetic field was studied. The compounds obey the Curie-Weiss law at temperatures above 100K, the Curie C, and Weiss {theta} constants for the methyl derivative being C=3.36cm{sup 3}Kmol{sup -1} and {theta}=-53K and for the ethyl derivative C=3.62cm{sup 3}Kmol{sup -1} and {theta}=-75K, respectively. The observed magnetic moments for Co atom at room temperature (i.e. {mu}{sub eff}=5.18 and 5.38 BM, respectively) are higher than those expected for a spin-only value for high spin Co(II) (S=3/2), revealing a substantial orbital contribution to the magnetic moment. The negative values of {theta} are an indication of the presence of antiferromagnetic exchange couplings between the near-neighbors Co(II) ions, within the layers. [Co(C{sub n}H{sub 2n+1}PO{sub 3})(H{sub 2}O)] (n=1,2) are 2D Ising antiferromagnets at low temperatures.

11. Protective Efficacy of an H5N1 Inactivated Vaccine Against Challenge with Lethal H5N1, H5N2, H5N6, and H5N8 Influenza Viruses in Chickens.

PubMed

Zeng, Xianying; Chen, Pucheng; Liu, Liling; Deng, Guohua; Li, Yanbing; Shi, Jianzhong; Kong, Huihui; Feng, Huapeng; Bai, Jie; Li, Xin; Shi, Wenjun; Tian, Guobin; Chen, Hualan

2016-05-01

12. Entecavir Interacts with Influx Transporters hOAT1, hCNT2, hCNT3, but Not with hOCT2: The Potential for Renal Transporter-Mediated Cytotoxicity and Drug–Drug Interactions

PubMed Central

Mandíková, Jana; Volková, Marie; Pávek, Petr; Navrátilová, Lucie; Hyršová, Lucie; Janeba, Zlatko; Pavlík, Jan; Bárta, Pavel; Trejtnar, František

2016-01-01

Entecavir (ETV) is one of the most potent agents for the treatment of the hepatitis B viral infection. The drug is principally eliminated by the kidney. The goal of this study was to investigate the potential of ETV to interact in vitro with the renal SLC transporters hOAT1, hOCT2, hCNT2 and hCNT3. Potential drug–drug interactions of ETV at the renal transporters with antiviral drugs known to be excreted by the kidney (adefovir, tenofovir, cidofovir) as well as transporter-dependent cytotoxicity were also examined. Interactions with the selected transporters along with cytotoxicity were studied in several transiently transfected cellular models using specific substrates and inhibitors. ETV was found to be both a substrate and inhibitor of hOAT1 (IC50 = 175.3 μM), hCNT2 (IC50 = 241.9 μM) and hCNT3 (IC50 = 278.4 μM) transporters, although it interacted with the transporters with relatively low affinities. ETV inhibited the cellular uptake of adefovir, tenofovir, and cidofovir by hOAT1; however, effective inhibition was shown at ETV concentrations exceeding therapeutic levels. In comparison with adefovir, tenofovir, and cidofovir, ETV displayed no transporter-mediated cytotoxicity in cells transfected with hOAT1, hCNT2, and hCNT3. No significant interaction of ETV with hOCT2 was detected. The study demonstrates interactions of ETV with several human renal transporters. For the first time, an interaction of ETV with the hCNTs was proved. We show that the potency of ETV to cause nephrotoxicity and/or clinically significant drug-drug interactions related to the tested transporters is considerably lower than that of adefovir, tenofovir, and cidofovir. PMID:26779022

13. Spectral (FT-IR, FT-Raman, UV, and fluorescence), DFT, and solid state interaction analyses of (E)-4-(3,4-dimethoxybenzylideneamino)-1,5-dimethyl-2-phenyl-1H-pyrazol-3(2H)-one

2017-01-01

Here, the authors report a combined experimental and theoretical study on the molecular structure and vibrational spectral analyses of (E)-4-(3,4-dimethoxybenzylideneamino)-1,5-dimethyl-2-phenyl-1H-pyrazol-3(2H)-one (DMBADPP), a pyrazolone-based bioactive molecule. Density functional theory (DFT) calculations were carried out to obtain the ground state optimized geometry of the molecule using the B3LYP method and the 6-311G(d,p) basis set. Calculated results agreed well with X-ray data. The vibrational spectra of DMBADPP were calculated at the same level of theory and theoretical scaled vibrational frequencies and assignments were found to agree well with experimental FT-IR and FT-Raman values. Partial atomic charge and molecular electrostatic potential (MEP) surface map analyses were performed to study reactive sites. Calculated frontier molecular orbitals (FMOs) energies and chemical reactivity parameters indicated that the DMBADPP exhibits high polarizability and low kinetic susceptibility. Excitation energy, wavelength, and oscillator strength were calculated using the Time Dependant-DFT/B3LYP/6-311G(d,p) method and compared with experimental UV-Vis spectra obtained in ethanol. However, UV-Vis and fluorescence spectroscopic experiments showed that DMBADPP has good absorption and fluorescent properties and a large Stokes shift. In addition, the solid state behaviors of molecules in crystals were analyzed quantitatively and qualitatively using 3D Hirshfeld surface analysis and associated 2D fingerprint plots.

14. Synthesis and crystal structure of a copper complex with (E)-2-(4-(1H-1,2,4-triazol-1-yl)benzylidene)-3, 4-dihydronaphthalen-1(2H)-one ligand

SciTech Connect

Sun, Shu-Wen; Zhang, Xiao; Wang, Gao-Feng

2015-12-15

The title compound, C{sub 35}H{sub 23}CuF{sub 6}N{sub 3}O{sub 5}S{sub 2} (1), was synthesized by the reaction of Cu(tta){sub 2} and L{sup 1}, (L{sup 1} = (E)-2-(4-(1H-1,2,4-triazol-1-yl)benzylidene)-3, 4-dihydronaphthalen-1(2H)-one) in the dichloromethane solution. It crystallizes in the monoclinic, space group P2{sub 1}/c with a = 33.8388(5), b = 9.3874(2), c = 21.8194(4) Å, β = 95.522(2), V = 6898.9(2) Å{sup 3}, Z = 8, D{sub x} = 1.554 Mg/m{sup 3}, F(000) = 3272, µ = 0.834 mm{sup –1}, R{sub 1} = 0.0639, wR{sub 2} = 0.1637. The copper(II) ion of 1 is in a distorted square-pyramidal environment with four O atoms of the two tta ligands and one N atom of triazole ligand L{sup 1}. Single-crystal X-ray diffraction data revealed that the hydrogen bonds, weak C–H···π and π···π interactions in the crystals link the coordination units to form 3D supramolecular structures.

15. Pressure and temperature effects on 2H spin-lattice relaxation times and 1H chemical shifts in tert-butyl alcohol- and urea-D2O solutions

Yoshida, Koji; Ibuki, Kazuyasu; Ueno, Masakatsu

1998-01-01

The pressure and temperature effects of hydrophobic hydration were studied by NMR spectroscopy. The 1H chemical shifts (δ) were measured at 7.7, 29.9, and 48.4 °C under high pressure up to 294 MPa for HDO contained as impurity in neat D2O, 1 mol kg-1 tert-butyl alcohol (TBA)-D2O, and 1 mol kg-1 urea-D2O solutions, for the methyl group of TBA in the TBA-D2O solution, and for the amino group of urea in the urea-D2O solution. The 2H spin-lattice relaxation times (T1) were measured under the same conditions as the chemical shift measurements for D2O in neat D2O, TBA-D2O and urea-D2O solutions with organic contents up to 8 mol%. The following features are observed for the pressure effect on δ (HDO) and 2H-T1 in TBA-D2O solutions: (1) The δ (HDO) exhibits a downfield shift relative to that in neat D2O, and the difference of δ (HDO) between TBA solution and neat D2O becomes larger with increasing pressure at lower temperature. (2) The decrement of the rotational correlation time of water in the hydration shell of TBA (τcs) relative to the value at atmospheric pressure is smaller than that in the bulk (τc0). (3) The pressure coefficients of T1 are positive in dilute solutions but are negative in more than 4 to 5 mol% solutions. These results suggest that the hydrophobic hydration shell of TBA is different than the open structure of water present in bulk, and resists pressure more strongly than the open structure of water in the bulk. In solutions of 4 to 5 mol%, the hydration shell collapses. On the other hand, the τcs in the hydration shell of urea is slightly larger than that in bulk water at lower pressure, but is obviously larger at higher pressure. In view of the rotational motion of water molecules, urea seems to strengthen the water structure slightly rather than weaken it, although δ (HDO) approaches that in the bulk with pressure. It is difficult to classify urea into a structure maker or a breaker.

16. Kinetic isotope effects and tunneling in cyclic double and triple proton transfer between acetic acid and methanol in tetrahydrofuran studied by dynamic /sup 1/H and /sup 2/H NMR spectroscopy

SciTech Connect

Gerritzen, D.; Limbach, H.H.

1984-02-22

Previous studies of proton exchange and hydrogen bonding between acetic acid (A) and methanol (B) in tetrahydrofuran-d/sub 8/ have been extended to the study of the primary kinetic H/D isotope effects of the exchange. For this purpose a new combination of dynamic /sup 1/H and /sup 2/H NMR spectroscopy has been used to perform an ''NMR proton inventory''. The following rate law was obtained at deuterium fractions D=0 and D=1 of the exchangeable protonic sites: NU=k/sup LL/ C/sub A/C/sub B/+k/sub LLL/C/sub A//sup 2/C/sub B/ (L=H,D). This was attributed to a superposition of cyclic double and triple proton exchange involving one and two molecules of acetic acid and one molecule of methanol. Additional experiments were carried out at intermediate deuterium fractions. Thus, the kinetic HH/HD/DD and HHH/HHD/DDD isotope effects of the exchange as a function of the temperature was measured successfully. This has been achieved for the first time for well-defined intermolecular multiple-proton-transfer reactions. The possibility of determining the number of protons transferred in a chemical reaction by performing an NMR proton inventory is discussed. The rule of the geometric mean (RGM) is fulfilled for the kinetic isotope effects of the LLL process, which are almost independent of temperature within the margin of error. By contrast, the RGM is not fullfilled for the LL process, and the kinetic isotope effects depend strongly on the temperature. The energies of activation and frequency factors fit Bell's criteria of tunneling. The kinetic results are in good agreement with predictions of transition-state theory but can be explained by an intermolecular tunneling model. The results are proof that acetic acid and methanol form cyclic hydrogen-bonded 1:1 and 2:1 complexes which have very low concentration in tetrahydrofuran.

17. Human PIV-2 recombinant Sendai virus (rSeV) elicits durable immunity and combines with two additional rSeVs to protect against hPIV-1, hPIV-2, hPIV-3, and RSV.

PubMed

Jones, Bart; Zhan, Xiaoyan; Mishin, Vasiliy; Slobod, Karen S; Surman, Sherri; Russell, Charles J; Portner, Allen; Hurwitz, Julia L

2009-03-13

The human parainfluenza viruses (hPIVs) and respiratory syncytial viruses (RSVs) are the leading causes of hospitalizations due to respiratory viral disease in infants and young children, but no vaccines are yet available. Here we describe the use of recombinant Sendai viruses (rSeVs) as candidate vaccine vectors for these respiratory viruses in a cotton rat model. Two new Sendai virus (SeV)-based hPIV-2 vaccine constructs were generated by inserting the fusion (F) gene or the hemagglutinin-neuraminidase (HN) gene from hPIV-2 into the rSeV genome. The inoculation of either vaccine into cotton rats elicited neutralizing antibodies toward both homologous and heterologous hPIV-2 virus isolates. The vaccines elicited robust and durable antibodies toward hPIV-2, and cotton rats immunized with individual or mixed vaccines were fully protected against hPIV-2 infections of the lower respiratory tract. The immune responses toward a single inoculation with rSeV vaccines were long-lasting and cotton rats were protected against viral challenge for as long as 11 months after vaccination. One inoculation with a mixture of the hPIV-2-HN-expressing construct and two additional rSeVs (expressing the F protein of RSV and the HN protein of hPIV-3) resulted in protection against challenge viruses hPIV-1, hPIV-2, hPIV-3, and RSV. Results identify SeV vectors as promising vaccine candidates for four different paramyxoviruses, each responsible for serious respiratory infections in children.

18. trans-Diaqua{5,5'-[(E,E)-pyridine-2,6-diylbis(methylidynenitrilo)]bis[pyrimidine-2,4(1H,3H)-dione]}zinc(II) nitrate hexafluorophosphate trihydrate.

PubMed

Ozdemir, Namik; Dinçer, Muharrem; Doğaner, Gamze; Astley, Demet; Astley, Stephen T

2007-04-01

The title compound, [Zn(C(15)H(11)N(7)O(4))(H(2)O)(2)](NO(3))(PF(6)).3H(2)O, contains a mononuclear zinc(II) complex. The Zn(2+) centre is seven-coordinated in a slightly distorted pentagonal-bipyramidal geometry, with the two water O atoms located in the apical positions, and the pyridine N atom, the two imine N atoms and two carbonyl O atoms of the uracil groups located in the equatorial plane. The charge is balanced by PF(6)(-) and NO(3)(-) anions.

19. Palladium-catalyzed through-space C(sp(3))-H and C(sp(2))-H bond activation by 1,4-palladium migration: efficient synthesis of [3,4]-fused oxindoles.

PubMed

Piou, Tiffany; Bunescu, Ala; Wang, Qian; Neuville, Luc; Zhu, Jieping

2013-11-18

Palladium two step: Linear anilides were converted into the title compounds in good to excellent yields through a palladium-catalyzed domino carbopalladation/1,4-palladium shift sequence. The C(sp(3) )-H activation involves a seven-membered palladacycle, and is chemoselective in the presence of competitive C(sp(2) )H bonds. DMA=N,N-dimethylacetamide, OPiv=pivalate.

20. The discovery of Polo-like kinase 4 inhibitors: design and optimization of spiro[cyclopropane-1,3'[3H]indol]-2'(1'H).ones as orally bioavailable antitumor agents.

PubMed

Sampson, Peter B; Liu, Yong; Patel, Narendra Kumar; Feher, Miklos; Forrest, Bryan; Li, Sze-Wan; Edwards, Louise; Laufer, Radoslaw; Lang, Yunhui; Ban, Fuqiang; Awrey, Donald E; Mao, Guodong; Plotnikova, Olga; Leung, Genie; Hodgson, Richard; Mason, Jacqueline M; Wei, Xin; Kiarash, Reza; Green, Erin; Qiu, Wei; Chirgadze, Nickolay Y; Mak, Tak W; Pan, Guohua; Pauls, Henry W

2015-01-08

Polo-like kinase 4 (PLK4), a unique member of the polo-like kinase family of serine-threonine kinases, is a master regulator of centriole duplication that is important for maintaining genome integrity. Overexpression of PLK4 is found in several human cancers and is linked with a predisposition to tumorigenesis. Previous efforts to identify potent and efficacious PLK4 inhibitors resulted in the discovery of (E)-3-((1H-indazol-6-yl)methylene)indolin-2-ones, which are superseded by the bioisosteric 2-(1H-indazol-6-yl)spiro[cyclopropane-1,3′-indolin]-2′-ones reported herein. Optimization of this new cyclopropane-linked series was based on a computational model of a PLK4 X-ray structure and SAR attained from the analogous alkenelinked series. The racemic cyclopropane-linked compounds showed PLK4 affinity and antiproliferative activity comparable to their alkene-linked congeners with improved hysicochemical, ADME, and pharmacokinetic properties. Positive xenograft results from the MDA-MB-468 human breast cancer xenograft model for compound 18 support the investigation of PLK4 inhibitors as anticancer therapeutics. A PLK4 X-ray co-structure with racemate 18 revealed preferential binding of the 1R,2S enantiomer to the PLK4 kinase domain.

1. Shaken not stirred: a facile synthesis of 1,4-bis(furo[2,3-d]-pyrimidine-2,4(1H,3H)-dione-5-yl)benzenes by one-pot reaction of isocyanides, N,N'-dimethylbarbituric acid, and terephthaldialdehyde.

PubMed

2006-07-15

A simple and efficient synthesis of 1,4-bis(furo[2,3-d]pyrimidine-2,4(1H,3H)-dione-5-yl)benzene derivatives was achieved via a one-pot three-component reaction of isocyanides, N,N'-dimethylbarbituric acid, and terephthaldialdehyde in DMF at room temperature for 30 min. These improved reaction conditions allow the preparation of highly substituted furopyrimidinones in high yields and purity under mild reaction conditions.

2. Synthesis of pyrrolo[2,1-f][1,2,4]triazin-4(3H)-ones: Rearrangement of pyrrolo[1,2-d][1,3,4]oxadiazines and regioselective intramolecular cyclization of 1,2-biscarbamoyl-substituted 1H-pyrroles

PubMed Central

Son, Kkonnip

2016-01-01

Summary Pyrrolo[2,1-f][1,2,4]triazin-4(3H)-ones 12 have been easily prepared via nucleophile-induced rearrangement of pyrrolooxadiazines 11 and regioselective intramolecular cyclization of 1,2-biscarbamoyl-substituted 1H-pyrroles 10. In this work, we demonstrated that the described synthetic approaches can be considered to be more facile and practical than previously reported procedures. PMID:27829885

3. Surface and catalytic elucidation of Rh/gamma-Al2O3 catalysts during NO reduction by C3H8 in the presence of excess O2, H2O, and SO2.

PubMed

Pekridis, G; Kaklidis, N; Komvokis, V; Athanasiou, C; Konsolakis, M; Yentekakis, I V; Marnellos, G E

2010-03-25

The present study aims at exploring the surface and catalytic behavior of Rh/gamma-Al(2)O(3) catalysts during the selective reduction of NO by C(3)H(8) in the presence of excess oxygen, H(2)O, and SO(2) with particular emphasis on identifying the elementary steps that describe the reaction mechanism. To this end, detailed activity and stability tests were employed and a precise kinetic analysis was carried out at differential conditions to elucidate the effect of each reactant, including H(2)O and SO(2), on the total reaction rate. At the same time, temperature programmed desorption (TPD) studies in combination with in situ diffuse reflectance infrared Fourier transform (DRIFT) spectroscopy were carried out under various reaction conditions to correlate the catalytic performance of Rh/gamma-Al(2)O(3) catalyst with its corresponding surface chemistry. The results reveal that in the absence of H(2)O and SO(2), the reaction follows a typical "reduction" type mechanism, where the active intermediates (NO(X), carboxylates, isocyanates) are interacting to yield the final products. In this reaction sequence the formation of carboxylate (C(x)H(y)O(z)) species is considered as the rate determining step. Water affects in a different way the NO and C(3)H(8) conversion performance of Rh/gamma-Al(2)O(3) catalyst; its effect is totally reversible in the case of C(3)H(8) oxidation, while the NO reduction was permanently affected mainly due to the oxidation of Rh active sites. In contrast, SO(2) poisons both reactions irreversibly via the formation of strongly adsorbed sulfate compounds, which hinder the adsorption and consequently the activation of reactants.

4. [Bis((2,4-dioxo-1,2,3,4-tetrahydroquinazolin-3-yl)alkyl)disulfane and 3-(mercaptoalkyl)quinazolin-2,4(1H,3H)-dione: synthesis by ring transformation and antiviral activity. 42. Heterocyclic azines with heteroatoms in the 1- and 3- positions].

PubMed

Gütschow, M; Tonew, E; Leistner, S

1995-10-01

Reaction of N-(sulfonyloxy)phtalimide derivatives 1, 2, with cystamine and homocystamine, respectively, affords bis[2,4-dioxol-1,2,3,4-tetra-hydroquinazolin-3-yl)alkyl] disulfanes [sequence: see text] 3, which could be reduced to 3-(mercaptoalkyl)quinazoline-2,4(1H,3H)-diones. 5. (3-(2-Mercaptoethyl)quinazoline-2,4(1H,3H)-dione (5a) was also obtained in a one-pot reaction from 1 or 2 and cysteamine. 2-Ethoxy-4H-3,1-benzoxazin-4-ones 4a-c were converted with cysteamine to 3-(mercaptoethyl)quinazoline-2,4-diones 5a-c by a new ringtransformation reaction. 3-(2-Mercaptoethyl)quinazoline-2,4(1H,3H)dione (5a) and the corresponding disulfane 3a were evaluated for antiviral activity in vitro. Compounds 3a and 5a showed significant antiviral activity against some DNA- and RNA-viruses (vaccinia-, herpes simplex virus type 1; influenza A virus) at concentrations that were nontoxic to the host cell cultures.

5. Structure vs. composition: A solid-state 1H and 29Si NMR study of quenched glasses along the Na 2O-SiO 2-H 2O join

Cody, George D.; Mysen, Bjorn O.; Lee, Sung Keun

2005-05-01

A suite of six hydrous (7 wt.% H 2O) sodium silicate glasses spanning sodium octasilicate to sodium disilicate in composition were analyzed using 29Si single pulse (SP) magic angle spinning (MAS) nuclear magnetic resonance (NMR) spectroscopy, 1H- 29Si cross polarization (CP) MAS NMR, and fast MAS 1H-NMR. From the 29Si SPMAS data it is observed that at low sodium compositions dissolved water significantly depolymerizes the silicate network. At higher sodium contents, however, dissolved H 2O does not affect a significant increase in depolymerization over that predicted based on the Na/Si ratio alone. The fast MAS 1H-NMR data reveal considerable complexity in proton environments in each of the glasses studied. The fast MAS 1H-NMR spectra of the highest sodium concentration glasses do not exhibit evidence of signficantly greater fractions of dissolved water as molecular H 2O than the lower sodium concentration glasses requiring that the decrease in polymerization at high sodium contents involves a change in sodium solution mechanism. Variable contact time 1H- 29Si cross polarization (CP) MAS NMR data reveal an increase in the rotating frame spin lattice relaxation rate constant ( T1ρ*) for various Q n species with increasing sodium content that correlates with a reduction in the average 1H- 29Si coupling strength. At the highest sodium concentration, however, T1ρ* drops significantly, consistent with a change in the Na 2O solution mechanism.

6. Microcrystalline phase transformation from ZrF4·HF·2H2O to ZrO2 through the intermediate phases ZrF4·3H2O, ZrF4·H2O, Zr2OF6·H2O and ZrF4

Dey, C. C.

2014-09-01

The behavior of hydrated zirconium fluoride has been studied by perturbed angular correlation spectroscopy. It is found that the crystalline compound ZrF4·HF·2H2O, formed initially by drying solution of Zr metal in concentrated HF, transforms spontaneously to ZrF4·3H2O. This trihydrated compound dehydrates to ZrF4 through the intermediate monohydrates ZrF4·H2O and Zr2OF6·H2O. The compound ZrF4 finally transforms to ZrO2 at ∼343 K. Different crystalline phases of ZrF4·HF·2H2O, ZrF4·3H2O, ZrF4·H2O, Zr2OF6·H2O, ZrF4 and ZrO2 have been identified and characterized by PAC spectroscopy. From previous PAC measurements, the intermediate ZrF4·H2O and Zr2OF6·H2O were not observed and the dehydration from ZrF4·3H2O to ZrF4 was found to be routed directly. Present measurements by PAC exhibits dissimilar crystal structures for ZrF4·3H2O and ZrF4·H2O unlike the crystal structures found in hafnium analogous compounds.

7. Copper diphosphonates with zero-, one- and two-dimensional structures: ferrimagnetism in layer compound Cu3(ImhedpH)(2).2H2O [ImhedpH4=(1-C3H3N2)CH2C(OH)(PO3H2)2].

PubMed

Cao, Deng-Ke; Xie, Xiao-Ji; Li, Yi-Zhi; Zheng, Li-Min

2008-10-07

Reactions of CuSO4 with 2-(1-imidazole)-1-hydroxy-1,1'-ethylidenediphosphonic acid (ImhedpH4) under hydrothermal conditions at different temperatures lead to four new metal phosphonates: Cu(ImhedpH3)2(H2O).2H2O (), Cu(ImhedpH3)2 (), Cu3(ImhedpH2)2(ImhedpH3)(2).4H2O (), and Cu3(ImhedpH)(2).2H2O (). Compounds and have mononuclear structures in which the Cu atoms adopt square pyramidal and square planar geometries, respectively. In compound , a chain structure is observed where the Cu3(ImhedpH2)2(ImhedpH3)2 trimer units are connected by edge-sharing of the {Cu2O5} square pyramids. Compound exhibits a layer structure made up of Cu3(ImhedpH)2 trimer units. The connection of trimers through corner-sharing of {Cu1O4} and {CPO3} tetrahedra results in a two-dimensional layer containing 8- and 16-membered rings. The imidazole groups are grafted on the two sides of the layer. Magnetic studies reveal that ferromagnetic interactions are mediated in , while for compound , ferrimagnetism is observed below 5.8 K.

8. Metal phosphonates based on aminomethylenediphosphonate: Syntheses and characterization of Na{sub 4}Zn{l_brace}NH{sub 3}CH(PO{sub 3}){sub 2}{r_brace}{sub 2}.4H{sub 2}O, Ni{l_brace}NH{sub 3}CH(PO{sub 3}H){sub 2}{r_brace}{sub 2}.xH{sub 2}O and NaNi{sub 2}{l_brace}NH{sub 3}CH(PO{sub 3})(PO{sub 3}H{sub 0.5}){r_brace}{sub 2}(H{sub 2}O){sub 2}.2H{sub 2}O

SciTech Connect

Bao Songsong; Wang Tianwei; Li Yizhi; Zheng Limin . E-mail: lmzheng@nju.edu.cn

2006-02-15

This paper describes the syntheses of three transition metal diphosphonate compounds: Na{sub 4}Zn{l_brace}NH{sub 3}CH(PO{sub 3}){sub 2}{r_brace}{sub 2}.4H{sub 2}O (1), Ni{l_brace}NH{sub 3}CH(PO{sub 3}H){sub 2}{r_brace}{sub 2}.xH{sub 2}O (2) and NaNi{sub 2}{l_brace}NH{sub 3}CH(PO{sub 3})(PO{sub 3}H{sub 0.5}){r_brace}{sub 2}(H{sub 2}O){sub 2}.2H{sub 2}O (3). Compound 1 contains chains of [Zn{l_brace}NH{sub 3}CH(PO{sub 3}){sub 2}{r_brace}{sub 2}]{sub n}{sup 4n-} made up of corner-sharing ZnO{sub 6} octahedra and CPO{sub 3} tetrahedra, which are further connected by tetramers of edge-sharing NaO{sub 6} octahedra, forming a three-dimensional open-framework structure. Compound 2 shows a square-grid layer structure where the NiO{sub 6} octahedra are corner shared with CPO{sub 3} tetrahedra. The adjacent layers are linked by strong inter-layer hydrogen bonds, resulting in a three-dimensional open-network structure with channels where the lattice water molecules reside. The structure of compound 3 is analogous to that of NaCo{sub 2}{l_brace}NH{sub 3}CH(PO{sub 3})(PO{sub 3}H{sub 0.5}){r_brace}{sub 2}(H{sub 2}O){sub 2}.xH{sub 2}O in which layers of Ni{sub 2}{l_brace}NH{sub 3}CH(PO{sub 3})(PO{sub 3}H{sub 0.5}){r_brace}{sub 2}(H{sub 2}O){sub 2} are connected by NaO{sub 6} linkages into an open-framework structure. The magnetic studies show that weak antiferromagnetic interactions are mediated between the nickel ions in compounds 2 and 3. Crystal data for 1: triclinic, space group P-1, a=5.551(2)A, b=6.166(2)A, c=12.424(4)A, {alpha}=92.422(6){sup o}, {beta}=92.687(7){sup o}, {gamma}=93.926(6){sup o}, V=423.3(2)A{sup 3}, Z=2. For 2: triclinic, space group P-1, a=9.043(1)A, b=9.180(1)A, c=9.271(1)A, {alpha}=89.693(3){sup o}, {beta}=70.202(3){sup o}, {gamma}=89.530(3){sup o}, V=724.1(2)A{sup 3}, Z=2.

9. [Polycyclic azines with heteroatoms in the 1- and 3-position. 40. Synthesis of heterocyclic immunomodulators. 3. Synthesis of n-1 substituted 3-(2-mercaptoethyl)quinazoline-2,4-(1H,3H)-diones from bis(2-(2-aminobenzoylamino)ethyl)disulfane and testing of immunostimulant activity].

PubMed

Gütschow, M; Drössler, K; Leistner, S

1995-03-01

A 3-step synthesis, starting from substituted isatoic anhydride was used to prepare substituted 3-(2-mercaptoethyl)quinazoline-2,4(1H,3H)-diones 4. Reaction of 1 with cystamine afforded bis[2-(2-amino-benzoyl-amino)ethyl]disulfanes 2. Reaction of 2 with ethyl chloroformate and subsequent reduction of the heterocyclic disulfanes 3 gave mercaptoethylquinazoline-2,4-diones 4a-f.N-1 methyl and benzyl substituted derivatives 4b and 4c, respectively, show immuno-stimulating activity in various tests.

10. N-(4-Nitrobenzoyl)-N'-(1,5-dimethyl-3-oxo-2-phenyl-1H-3(2H)-pyrazolyl)-thiourea hydrate: Synthesis, spectroscopic characterization, X-ray structure and DFT studies

Arslan, N. Burcu; Kazak, Canan; Aydın, Fatma

2012-04-01

The title molecule (C19H17N5O4S·H2O) was synthesized and characterized by IR-NMR spectroscopy, MS and single-crystal X-ray diffraction. The molecular geometry, vibrational frequencies and gauge-independent atomic orbital (GIAO) 1H and 13C NMR chemical shift values of the compound in the ground state have been calculated by using the density functional theory (DFT) method with 6-31G(d) basis set, and compared with the experimental data. All the assignments of the theoretical frequencies were performed by potential energy distributions using VEDA 4 program. The calculated results show that the optimized geometries can well reproduce the crystal structural parameters, and the theoretical vibrational frequencies and 1H and 13C NMR chemical shift values show good agreement with experimental data. To determine conformational flexibility, the molecular energy profile of the title compound was obtained with respect to the selected torsion angle, which was varied from -180° to +180° in steps of 10°. Besides, molecular electrostatic potential (MEP), frontier molecular orbitals (FMO) analysis and thermodynamic properties of the compound were investigated by theoretical calculations.

11. Serological comparison of antibodies to avian influenza viruses, subtypes H5N2, H6N1, H7N3 and H7N9 between poultry workers and non-poultry workers in Taiwan in 2012.

PubMed

Huang, S Y; Yang, J R; Lin, Y J; Yang, C H; Cheng, M C; Liu, M T; Wu, H S; Chang, F Y

2015-10-01

In Taiwan, avian influenza virus (AIV) subtypes H5N2, H6N1 and H7N3 have been identified in domestic poultry, and several strains of these subtypes have become endemic in poultry. To evaluate the potential of avian-to-human transmission due to occupational exposure, an exploratory analysis of AIV antibody status in poultry workers was conducted. We enrolled 670 poultry workers, including 335 live poultry vendors (LPVs), 335 poultry farmers (PFs), and 577 non-poultry workers (NPWs). Serum antibody titres against various subtypes of viruses were analysed and compared. The overall seropositivity rates in LPVs and PFs were 2·99% (10/335) and 1·79% (6/335), respectively, against H5N2; and 0·6% (2/335) and 1·19% (4/335), respectively, for H7N3 virus. Of NPWs, 0·35% (2/577) and 0·17% (1/577) were seropositive for H5N2 and H7N3, respectively. Geographical analysis revealed that poultry workers whose workplaces were near locations where H5N2 outbreaks in poultry have been reported face greater risks of being exposed to viruses that result in elevated H5N2 antibody titres. H6N1 antibodies were detected in only one PF, and no H7N9 antibodies were found in the study subjects. Subclinical infections caused by H5N2, H6N1 and H7N3 viruses were thus identified in poultry workers in Taiwan. Occupational exposure is associated with a high risk of AIV infection, and the seroprevalence of particular avian influenza strains in humans reflects the endemic strains in poultry in this region.

12. In Silico Identification of Highly Conserved Epitopes of Influenza A H1N1, H2N2, H3N2, and H5N1 with Diagnostic and Vaccination Potential.

PubMed

Muñoz-Medina, José Esteban; Sánchez-Vallejo, Carlos Javier; Méndez-Tenorio, Alfonso; Monroy-Muñoz, Irma Eloísa; Angeles-Martínez, Javier; Santos Coy-Arechavaleta, Andrea; Santacruz-Tinoco, Clara Esperanza; González-Ibarra, Joaquín; Anguiano-Hernández, Yu-Mei; González-Bonilla, César Raúl; Ramón-Gallegos, Eva; Díaz-Quiñonez, José Alberto

2015-01-01

The unpredictable, evolutionary nature of the influenza A virus (IAV) is the primary problem when generating a vaccine and when designing diagnostic strategies; thus, it is necessary to determine the constant regions in viral proteins. In this study, we completed an in silico analysis of the reported epitopes of the 4 IAV proteins that are antigenically most significant (HA, NA, NP, and M2) in the 3 strains with the greatest world circulation in the last century (H1N1, H2N2, and H3N2) and in one of the main aviary subtypes responsible for zoonosis (H5N1). For this purpose, the HMMER program was used to align 3,016 epitopes reported in the Immune Epitope Database and Analysis Resource (IEDB) and distributed in 34,294 stored sequences in the Pfam database. Eighteen epitopes were identified: 8 in HA, 5 in NA, 3 in NP, and 2 in M2. These epitopes have remained constant since they were first identified (~91 years) and are present in strains that have circulated on 5 continents. These sites could be targets for vaccination design strategies based on epitopes and/or as markers in the implementation of diagnostic techniques.

13. In Silico Identification of Highly Conserved Epitopes of Influenza A H1N1, H2N2, H3N2, and H5N1 with Diagnostic and Vaccination Potential

PubMed Central

Muñoz-Medina, José Esteban; Sánchez-Vallejo, Carlos Javier; Méndez-Tenorio, Alfonso; Monroy-Muñoz, Irma Eloísa; Angeles-Martínez, Javier; Santos Coy-Arechavaleta, Andrea; Santacruz-Tinoco, Clara Esperanza; González-Ibarra, Joaquín; Anguiano-Hernández, Yu-Mei; González-Bonilla, César Raúl; Ramón-Gallegos, Eva; Díaz-Quiñonez, José Alberto

2015-01-01

The unpredictable, evolutionary nature of the influenza A virus (IAV) is the primary problem when generating a vaccine and when designing diagnostic strategies; thus, it is necessary to determine the constant regions in viral proteins. In this study, we completed an in silico analysis of the reported epitopes of the 4 IAV proteins that are antigenically most significant (HA, NA, NP, and M2) in the 3 strains with the greatest world circulation in the last century (H1N1, H2N2, and H3N2) and in one of the main aviary subtypes responsible for zoonosis (H5N1). For this purpose, the HMMER program was used to align 3,016 epitopes reported in the Immune Epitope Database and Analysis Resource (IEDB) and distributed in 34,294 stored sequences in the Pfam database. Eighteen epitopes were identified: 8 in HA, 5 in NA, 3 in NP, and 2 in M2. These epitopes have remained constant since they were first identified (~91 years) and are present in strains that have circulated on 5 continents. These sites could be targets for vaccination design strategies based on epitopes and/or as markers in the implementation of diagnostic techniques. PMID:26346523

14. Onflow liquid chromatography at critical conditions coupled to (1)H and (2)H nuclear magnetic resonance as powerful tools for the separation of poly(methylmethacrylate) according to isotopic composition.

PubMed

Hehn, Mathias; Sinha, Pritish; Pasch, Harald; Hiller, Wolf

2015-03-27

The present work addresses a major challenge in polymer chromatography by developing a method to separate and analyze polymers with identical molar masses, chemical structures and tacticities that is solely based on differences in isotope composition. For the first time, liquid chromatography at critical conditions (LCCC) was used to separate PMMA regarding the H and D isotopes. At critical conditions of H-PMMA, D-PMMA eluted in the adsorption mode and vice versa. By online onflow LCCC-NMR, both PMMA species were clearly identified. Different from other detectors, NMR can distinguish between H and D. Onflow LCCC-H/NMR and LCCC-D/NMR measurements were carried out and the H/D-blend components were detected. (1)H and (13)C NMR provided the tacticity of protonated PMMA. Double resonance (13)C{H} and triple resonance (13)C{H,D} provided the tacticity of the deuterated samples. Samples with similar tacticities were used to ensure that separation occurs solely regarding the isotope labeling.

15. ON THE FORMATION AND ISOMER SPECIFIC DETECTION OF PROPENAL (C{sub 2}H{sub 3}CHO) AND CYCLOPROPANONE (c-C{sub 3}H{sub 4}O) IN INTERSTELLAR MODEL ICES—A COMBINED FTIR AND REFLECTRON TIME-OF-FLIGHT MASS SPECTROSCOPIC STUDY

SciTech Connect

Abplanalp, Matthew J.; Borsuk, Aleca; Jones, Brant M.; Kaiser, Ralf I.

2015-11-20

The formation routes of two structural isomers—propenal (C{sub 2}H{sub 3}CHO) and cyclopropanone (c-C{sub 3}H{sub 4}O)—were investigated experimentally by exposing ices of astrophysical interest to energetic electrons at 5.5 K thus mimicking the interaction of ionizing radiation with interstellar ices in cold molecular clouds. The radiation-induced processing of these ices was monitored online and in situ via Fourier Transform Infrared spectroscopy and via temperature programmed desorption exploiting highly sensitive reflectron time-of-flight mass spectrometry coupled with single photon ionization in the post irradiation phase. To selectively probe which isomer(s) is/are formed, the photoionization experiments were conducted with 10.49 and 9.60 eV photons. Our studies provided compelling evidence on the formation of both isomers—propenal (C{sub 2}H{sub 3}CHO) and cyclopropanone (c-C{sub 3}H{sub 4}O)—in ethylene (C{sub 2}H{sub 4})—carbon monoxide (CO) ices forming propenal and cyclopropanone at a ratio of (4.5 ± 0.9):1. Based on the extracted reaction pathways, the cyclopropanone molecule can be classified as a tracer of a low temperature non-equilibrium chemistry within interstellar ices involving most likely excited triplet states, whereas propenal can be formed at ultralow temperatures, but also during the annealing phase via non-equilibrium as well as thermal chemistry (radical recombination). Since propenal has been detected in the interstellar medium and our laboratory experiments demonstrate that both isomers originated from identical precursor molecules our study predicts that the hitherto elusive second isomer—cyclopropanone—should also be observable toward those astronomical sources such as Sgr B2(N) in which propenal has been detected.

16. CAF-1-induced oligomerization of histones H3/H4 and mutually exclusive interactions with Asf1 guide H3/H4 transitions among histone chaperones and DNA.

PubMed

Liu, Wallace H; Roemer, Sarah C; Port, Alex M; Churchill, Mair E A

2012-12-01

Anti-silencing function 1 (Asf1) and Chromatin Assembly Factor 1 (CAF-1) chaperone histones H3/H4 during the assembly of nucleosomes on newly replicated DNA. To understand the mechanism of histone H3/H4 transfer among Asf1, CAF-1 and DNA from a thermodynamic perspective, we developed and employed biophysical approaches using full-length proteins in the budding yeast system. We find that the C-terminal tail of Asf1 enhances the interaction of Asf1 with CAF-1. Surprisingly, although H3/H4 also enhances the interaction of Asf1 with the CAF-1 subunit Cac2, H3/H4 forms a tight complex with CAF-1 exclusive of Asf1, with an affinity weaker than Asf1-H3/H4 or H3/H4-DNA interactions. Unlike Asf1, monomeric CAF-1 binds to multiple H3/H4 dimers, which ultimately promotes the formation of (H3/H4)(2) tetramers on DNA. Thus, transition of H3/H4 from the Asf1-associated dimer to the DNA-associated tetramer is promoted by CAF-1-induced H3/H4 oligomerization.

17. Eco-friendly methodology to prepare N-heterocycles related to dihydropyridines: microwave-assisted synthesis of alkyl 4-arylsubstituted-6-chloro-5-formyl-2-methyl-1,4-dihydropyridine-3-carboxylate and 4-arylsubstituted-4,7-dihydrofuro[3,4-b]pyridine-2,5(1H,3H)-dione.

PubMed

Rodríguez, Hortensia; Martin, Osnieski; Suarez, Margarita; Martín, Nazario; Albericio, Fernando

2011-11-21

Here we describe the efficient synthesis of alkyl 4-arylsubstituted-6-chloro-5-formyl-2-methyl-1,4-dihydropyridine-3-carboxylates and 4-arylsubstituted-4,7-dihydro-furo[3,4-b]pyridine-2,5(1H,3H)-diones via microwave-accelerated reaction of alkyl 4-arylsubstituted-2-methyl-6-oxo-1,4,5,6-tetrahydro-3-pyridinecarboxylates with the appropriate reagents. This eco-friendly approach to these valuable dihydropyridine derivatives does not involve the harsh or highly contaminating conditions common in classical heating and offers a reduction or even elimination of solvent use and recovery, simplification of the work-up procedures, facility of scale up, and low energy consumption, in addition to moderate to higher yields.

18. Antitumor activity of 6-(cyclohexylamino)-1, 3-dimethyl-5(2-pyridyl)furo[2,3-d]pyrimidine-2,4(1H,3H)-dione and Its Ti(IV), Zn(II), Fe(III), and Pd(II) complexes on K562 and Jurkat cell lines.

PubMed

Shabani, Fahmideh; Ghammamy, Shahriar; Mehrani, Khayroallah; Teimouri, Mohammad Bagher; Soleimani, Masoud; Kaviani, Saeid

2008-01-01

(6-(cyclohexylamino)-1,3-dimethyl-5(2-pyridyl)furo[2,3-d]pyrimidine-2,4(1H,3H)-dione) abbreviated as CDP was synthesized and characterized. Ti(IV), Zn(II), Fe(III), and Pd(II) metal complexes of this ligand are prepared by the reaction of salts of Ti(IV), Zn(II), Fe(III), and Pd(II) with CDP in acetonitrile. Characterization of the ligand and its complexes was made by microanalyses, FT-IR, (1)H NMR, (13)C NMR, and UV-Visible spectroscopy. All complexes were characterized by several techniques using elemental analysis (C, H, N), FT-IR, electronic spectra, and molar conductance measurements. The elemental analysis data suggest the stoichiometry to be 1:1 [M:L] ratio formation. The molar conductance measurements reveal the presence of 1:1 electrolytic nature complexes. These new complexes showed excellent antitumor activity against two kinds of cancer cells that are K562 (human chronic myeloid leukemia) cells and Jurkat (human T lymphocyte carcinoma) cells.

19. Electronic structures and selective fluoride sensing features of Os(bpy)2(HL(2-)) and [{Os(bpy)2}2(μ-HL(2-))](2+) (H3L: 5-(1H-benzo[d]imidazol-2-yl)-1H-imidazole-4-carboxylic acid).

PubMed

Das, Ankita; Agarwala, Hemlata; Kundu, Tanaya; Ghosh, Prabir; Mondal, Sudipta; Mobin, Shaikh M; Lahiri, Goutam Kumar

2014-10-07

The article deals with the newly designed mononuclear and asymmetric dinuclear osmium(ii) complexes Os(II)(bpy)2(HL(2-)) (1) and [(bpy)2Os(II)(μ-HL(2-))Os(II)(bpy)2](Cl)2 ([2](Cl)2)/[(bpy)2Os(II)(μ-HL(2-))Os(II)(bpy)2](ClO4)2 ([2](ClO4)2), respectively, (H3L = 5-(1H-benzo[d]imidazol-2-yl)-1H-imidazole-4-carboxylic acid and bpy = 2,2'-bipyridine). The identity of 1 has been established by its single crystal X-ray structure. The ligand (HL(2-))-based primary oxidation process (E, 0.23 V versus SCE) along with the partial metal contribution (∼20%) in 1 has been revealed by the ligand-dominated HOMO of 1 (HL(2-): 88%, Os: 8%), as well as by the Mulliken spin density distribution of 1(+) (HL(2-): 0.878, Os: 0.220). Accordingly, 1(+) exhibits a free radical type EPR at 77 K with a partial metal-based anisotropic feature (g1 = 2.127, g2 = 2.096, g3 = 2.046; = 2.089; Δg = 0.08). (1)H-NMR of the dinuclear 2(2+) in CDCl3 suggests an intimate mixture of two diastereomeric forms in a 1 : 1 ratio. The DFT-supported predominantly Os(ii)/Os(iii)-based couples of asymmetric 2(2+) at 0.24 V and 0.50 V versus SCE result in a comproportionation constant (Kc) value of 8.2 × 10(4). The class I mixed valent state of 2(3+) (S = 1/2) has, however, been corroborated by the Mulliken spin density distribution of Os1: 0.887, Os2: 0.005, HL(2-): 0.117, as well as by the absence of a low-energy IVCT (intervalence charge transfer) band in the near-IR region (up to 2000 nm). The appreciable spin accumulation on the bridge in 2(3+) or 2(4+) (S = 1, Os1: 0.915, Os2: 0.811 and HL(2-): 0.275) implies a mixed electronic structural form of [(bpy)2Os(III)(μ-HL(2-))Os(II)(bpy)2](3+)(major)/[(bpy)2Os(II)(μ-HL˙(-))Os(II)(bpy)2](3+)(minor) or [(bpy)2Os(III)(μ-HL(2-))Os(III)(bpy)2](4+)(major)/[(bpy)2Os(III)(μ-HL˙(-))Os(II)(bpy)2](4+) (minor), respectively. The mixed valent {Os(III)(μ-HL(2-))Os(II)} state in 2(3+), however, fails to show EPR at 77 K due to the rapid spin relaxation

20. Simultaneous spectrophotometric determination of Cd2+, Cu2+, and Zn2+ in rice and vegetal samples with dimethyl-spiro[isobenzofurane-1,6'-pyrorolo[2,3-d]pyrimidine]-2',3,4,5'(1'H,3'H,7'H)tetraone using wavelet transformation-feed forward neural networks.

PubMed

2013-07-17

A multicomponent analysis method for the simultaneous spectrophotometric determination of the Cd(2+), Cu(2+), and Zn(2+) based on complex formation with dimethyl-spiro[isobenzofurane-1,6'-pyrorolo[2,3-d]pyrimidine]-2',3,4,5'(1'H,3'H,7'H)tetraone using wavelet transformation-feed forward neural network is proposed. The analytical data showed that metal to ligand ratios in all metal complexes was 1:1. The absorption spectra were evaluated with respect to synthetic ligand concentration and pH. It was found that, at pH 6.7, the complexation reactions were completed. Spectral data were reduced using continuous wavelet transformation (CWT) and subjected to artificial neural networks. The presence of nonlinearities was confirmed by a partial response plot. The structures of the CWT-feed forward neural networks (WT-FFNN) were simplified using the corresponding wavelet coefficients of mother wavelets. Once the optimal wavelet coefficients are selected, different ANN models can be employed for the calculation of the final calibration model. The proposed methods were successfully applied to the simultaneous determination of Cd(2+), Cu(2+), and Zn(2+) in rice, dill, tomato, and lettuce samples.

1. Crystal structure of (E)-2-[(2-bromopyridin-3-yl)methyl-idene]-6-meth-oxy-3,4-di-hydro-naphthalen-1(2H)-one and 3-[(E)-(6-meth-oxy-1-oxo-1,2,3,4-tetra-hydro-naphthalen-2-ylidene)meth-yl]pyridin-2(1H)-one.

PubMed

Zingales, Sarah K; Moore, Morgan E; Goetz, Andrew D; Padgett, Clifford W

2016-07-01

The title compounds C17H14BrNO2, (I), and C17H15NO3, (II), were obtained from the reaction of 6-meth-oxy-3,4-di-hydro-2H-naphthalen-1-one and 2-bromo-nicotinaldehyde in ethanol. Compound (I) was the expected product and compound (II) was the oxidation product from air exposure. In the crystal structure of compound (I), there are no short contacts or hydrogen bonds. The structure does display π-π inter-actions between adjacent benzene rings and adjacent pyridyl rings. Compound (II) contains two independent mol-ecules, A and B, in the asymmetric unit; both are non-planar, the dihedral angles between the meth-oxy-benzene and 1H-pyridin-2-one mean planes being 35.07 (9)° in A and 35.28 (9)°in B. In each mol-ecule, the 1H-pyridin-2-one unit participates in inter-molecular N-H⋯O hydrogen bonding to another mol-ecule of the same type (A to A or B to B). The structure also displays π-π inter-actions between the pyridyl and the benzene rings of non-equivalent mol-ecules (viz., A to B and B to A).

2. 7-Chloro-5-(4-hydroxyphenyl)-1-methyl-3-(naphthalen-2-ylmethyl)-4,5-dihydro-1H-benzo[b][1,4]diazepin-2(3H)-one (Bz-423), a benzodiazepine, suppresses keratinocyte proliferation and has antipsoriatic activity in the human skin-severe, combined immunodeficient mouse transplant model.

PubMed

Bhagavathula, Narasimharao; Nerusu, Kamalakar C; Hanosh, Andrew; Aslam, Muhammad N; Sundberg, Thomas B; Opipari, Anthony W; Johnson, Kent; Kang, Sewon; Glick, Gary D; Varani, James

2008-03-01

7-Chloro-5-(4-hydroxyphenyl)-1-methyl-3-(naphthalen-2-ylmethyl)-4,5-dihydro-1H-benzo[b][1,4]diazepin-2(3H)-one (Bz-423) is a benzodiazepine that has cytotoxic and cytostatic activity against a variety of cells in vivo and in vitro. In the present study, we demonstrate that Bz-423 (formulated for topical delivery) reduces epidermal hyperplasia in human psoriatic skin after transplantation to severe, combined immunodeficient (scid) mice. Bz-423 also suppresses the hyperplasia that develops in nonpsoriatic human skin as a consequence of transplantation to scid mice. Proliferation of human epidermal keratinocytes in monolayer culture was suppressed by Bz-423 at concentrations of 0.5 to 2.0 muM (noncytotoxic concentrations). Keratinocyte growth inhibition was accompanied by increased oxidant generation in Bz-423-treated cells, and treatment with vitamin E along with Bz-423 reversed the growth inhibition. Growth inhibition was accompanied by a redistribution of beta-catenin from a cytoplasmic pool to the cell membrane and by reduced levels of c-myc and cyclin D1 (two molecules associated with Wnt pathway signaling). Several analogs of Bz-423 were examined for antiproliferative activity against human epidermal keratinocytes and human dermal fibroblasts in monolayer culture. Each of the analogs tested suppressed growth of both cell types, but in all cases, keratinocytes were more sensitive than fibroblasts. Two of the compounds were found to suppress epidermal hyperplasia induced with all-trans retinoic acid in organ cultures of human skin. Taken together, these data show that Bz-423 and certain analogs produce biological responses in skin cells in vitro and in vivo that are consistent with therapeutic goals for treating psoriasis or epidermal hyperplasia resulting from other causes.

3. The Hydrothermal NH 4/V/P/H 2O and K/v/p/n(c 2H 5) 3/H 2O Systems at 473 K and the Crystal Structures of NH 4VOPO 4and (nh 4) 3V 2O 3(VO)(PO 4) 2(HPO 4)

Schindler, Michael; Joswig, Werner; Baur, Werner H.

1997-12-01

An examination of the NH 4/VO 5/P/H 2O system at 473 K under hydrothermal conditions yielded the (NH 4) 3V 2O 3(VO)(PO 4) 2(HPO 4) and NH 4VOPO 4phases. The crystal structure of the first compound is isotypical with the corresponding Tl +and K +phases. The cations NH +4and Tl +have similar coordinations against oxygen. The investigation of the crystal structure of the second compound (space group Pn2 n) shows it to be related to other ABO TO 4phases of the potassium titanyl phosphate type with A=Na +, Ag +, NH +4, Rb +, K +, and Tl +, and B=Ti 4+, V 4+, Sn 4+, Fe 4+, Ge 4+, Ga 3+, Zr 4+, Sb 5+, and Nb 5+, and T=P 5+, Ge 4+, Si 4+, and As 5+, but none of them crystallize in space group Pn2 n. In the K/V/P/N(C 2H 5) 3/H 2O system, three different K phases were found: K 0.5VOPO 4·1.5H 2O, KVOPO 4, and K-FVP-1 (Frankfurt vanadium phosphate, one, or for short, FVP-1). The microporous K-FVP-1 compound was synthesized in a similar pH range as the isotypic Na-FVP-1 phase. The V 4+/V 5+ratio of K-FVP-1 varies from 3.5(1)/1.5(1) to 1.6(1)/3.4(1) and the corresponding lattice constants range from 16.0013(6) to 15.7665(4) Å.

4. Protective activity of probiotic bacteria against 2-amino-3-methyl-3H-imidazo[4,5-f]quinoline (IQ) and 2-amino-1-methyl-6-phenyl-1H-imidazo[4,5-b]pyridine (PhIP) - an in vitro study.

PubMed

Nowak, Adriana; Czyżowska, Agata; Stańczyk, Małgorzata

2015-01-01

Heterocyclic aromatic amines (HAAs) are carcinogenic compounds present in a typical Western diet rich in thermally processed meat. These nutritional factors can modulate the cytotoxicity of faecal water (FW) and induce tumours in the human gastrointestinal tract. Supplementation with probiotics is promising in terms of reducing the harmful effects of HAAs in the human body. The aim of the study was in vitro assessment of the protective activity of the probiotic strains Lb. rhamnosus 0900, Lb. rhamnosus 0908, Lb. casei 0919 and Lb. casei DN 114001 against IQ (2-amino-3-methyl-3H-imidazo[4,5-f]quinoline) and PhIP (2-amino-1-methyl-6-phenyl-1H-imidazo[4,5-b]pyridine) after incubation with faeces from 15 persons aged 4 months to 82 years (children, adults and the elderly). The highest mean cytotoxicity of FW was observed for the elderly (63.2% ± 3.7%) and the lowest for children (28.0% ± 9.5%), as estimated by a neutral red uptake assay. The probiotics lowered the average cytotoxicity of FW exposed to IQ or PhIP. The concentration of IQ and PhIP in FW was most effectively reduced by Lb. rhamnosus 0900 (47.5%) and Lb. casei 0919 (45.8%), respectively, as determined by high -performance liquid chromatography. All the tested strains bound PhIP to a higher extent than IQ. In an alkaline comet assay, Lb. casei 0919 and Lb. rhamnosus 0908 displayed the strongest protective effect against IQ and PhIP (up to 80% reduction of DNA damage). Also in a comet assay, Lb. rhamnosus 0908 exhibited antioxidative activity toward H2O2 and PhIP (up to 63% and 69.5% reduction of oxidative DNA damage, respectively). The protective activity of the probiotic strains was specific to a given person's FW, which implies the involvement of intestinal microbiota in the process.

5. Crystal structures of three indole derivatives: 3-ethnyl-2-methyl-1-phenyl­sulfonyl-1H-indole, 4-phenyl­sulfonyl-3H,4H-cyclo­penta­[b]indol-1(2H)-one and 1-{2-[(E)-2-(5-chloro-2-nitro­phen­yl)ethen­yl]-1-phenyl­sulfonyl-1H-indol-3-yl}ethan-1-one chloro­form monosolvate

PubMed Central

Gopinath, S.; Sethusankar, K.; Ramalingam, Bose Muthu; Mohanakrishnan, Arasambattu K.

2015-01-01

The title compounds, C17H13NO2S, (I), C17H13NO3S, (II), and C24H17ClN2O5S·CHCl3, (III), are indole derivatives. Compounds (I) and (II) crystalize with two independent mol­ecules in the asymmetric unit. The indole ring systems in all three structures deviate only slightly from planarity, with dihedral angles between the planes of the pyrrole and benzene rings spanning the tight range 0.20 (9)–1.65 (9)°. These indole ring systems, in turn, are almost orthogonal to the phenyl­sulfonyl rings [range of dihedral angles between mean planes = 77.21 (8)–89.26 (8)°]. In the three compounds, the mol­ecular structure is stabilized by intra­molecular C—H⋯O hydrogen bonds, generating S(6) ring motifs with the sulfone O atom. In compounds (I) and (II), the two independent mol­ecules are linked by C—H⋯O hydrogen bonds and C—H⋯π inter­actions, while in compound (III), the mol­ecules are linked by C—H⋯O hydrogen bonds, generating R 2 2(22) inversion dimers. PMID:26396842

6. /sup 2/H-NMR studies of hypocotyl cell walls of germinating beams supplied with perdeuterated myo-inositol

SciTech Connect

Sasaki, K.; Wallace, J.C.; MacKay, A.L.; Balza, F.; Taylor, I.E.P.

1987-04-01

When myo-(2-/sup 3/H) inositol (MI) was supplied to bean seeds by imbibition, only uronic acid, arabinose and xylose residues of cell wall polysaccharides were labeled. To study the structural mobility of the uronic acid- and/or pentose-rich polysaccharides in cell wall using /sup 2/H-NMR, the authors supplied perdeuterated MI with (2-/sup 3/H) MI to germinating bean seeds. Perdeuterated MI was prepared by the /sup 1/H-/sup 2/H exchange reaction of MI in deuterium oxide with Raney nickel. During the exchange reaction, extensive epimerization occurred and at least 6 inositol epimers in addition to MI were identified in the reaction mixture of GC/MS. The perdeuterated MI was completely resolved from other inositol epimers and purified by anion-exchange chromatography using Dowex 1 (borate form) and by crystallization. The /sup 2/H-NMR analysis resolved the /sup 2/H-labeled hypocotyl cell walls into two components (rigid and mobile components). They also report the distribution of /sup 2/H and /sup 3/H from perdeuterated and (2-/sup 3/H) MI in the cell wall sugar residues.

7. Washout of tritium from 3R-3(/sup 3/H)-L-aspartate in the aspartase reaction

SciTech Connect

Katz, B.M.; Cook, P.F.

1987-05-01

Bacterial aspartase catalyzes the reversible conversion of L-aspartate to fumarate and ammonia. Recent studies that made use of deuterium and /sup 15/N isotope effects suggested a carbanion intermediate mechanism in which C-N bond cleavage is rate determining. This could result in removal of a proton from the 3R position of aspartate at a rate of faster than the elimination of ammonia. 3R-3(/sup 3/H)-Aspartate was prepared enzymatically using aspartase from fumarate, ammonia and /sup 3/H/sub 2/O and aspartate isolated via chromatography on Dowex 50W x 8 at pH 1, eluting with 2N pyridine. The rate of /sup 3/H washout from this aspartate was then measured as a function of aspartate concentration and compared to the rate of production of fumarate. Tritium does washout of aspartate at a rate faster than fumarate is formed but the proton is apparently not rapidly equilibrated with solvent. The tritium washout experiments were supplemented using 3R-3(/sup 2/H)-aspartate prepared as above with /sup 2/H/sub 2/O replacing /sup 3/H/sub 2/O and monitoring the appearance of 3R-3(/sup 1/H)-aspartate via /sup 1/H-NMR. Results confirm the tritium washout results. Data are discussed in terms of the carbanion mechanism.

8. Oxidation of potentials of the Me(IV)-Me(III) couple and the thermodynamics of the reactions Me/sup 3 +/ + H/sup +/ reversible Me/sup 4 +/ + 1/2H/sub 2/ (Me = Bk, Ce) in different media

SciTech Connect

Timofeev, G.A.; Chistyakov, V.M.; Erin, E.A.; Baranov, A.A.

1987-11-01

The values of the real oxidation potentials E/sub p//sup 0/ of the couples Bk(IV)-Bk(III) in solutions of perchloric, nitric, and phosphoric acids, potassium phosphotungstate, and sodium and potassium carbonates are measured by differential coulopotentiometry. It is shown that when solutions of sulfuric acid phosphoric acids, potassium phosphotungstate, and sodium and potassium carbonates are used in place of perchloric and nitric acids the E/sub p//sup 0/ value moves in the negative direction for both berkelium and cerium, which indicates strong complexation of ions of these elements. The thermodynamic parameters ..delta..G, ..delta..H, and ..delta..S of the reaction Me/sup 3 +/ + H/sup +/ reversible Me/sup 4 +/ + 12 H/sub 2/ (Me = Bk, Ce) are determined

9. Crystal structure of (E)-2-[(2-bromopyridin-3-yl)methyl­idene]-6-meth­oxy-3,4-di­hydro­naphthalen-1(2H)-one and 3-[(E)-(6-meth­oxy-1-oxo-1,2,3,4-tetra­hydro­naphthalen-2-ylidene)meth­yl]pyridin-2(1H)-one

PubMed Central

Zingales, Sarah K.; Moore, Morgan E.; Goetz, Andrew D.; Padgett, Clifford W.

2016-01-01

The title compounds C17H14BrNO2, (I), and C17H15NO3, (II), were obtained from the reaction of 6-meth­oxy-3,4-di­hydro-2H-naphthalen-1-one and 2-bromo­nicotinaldehyde in ethanol. Compound (I) was the expected product and compound (II) was the oxidation product from air exposure. In the crystal structure of compound (I), there are no short contacts or hydrogen bonds. The structure does display π–π inter­actions between adjacent benzene rings and adjacent pyridyl rings. Compound (II) contains two independent mol­ecules, A and B, in the asymmetric unit; both are non-planar, the dihedral angles between the meth­oxy­benzene and 1H-pyridin-2-one mean planes being 35.07 (9)° in A and 35.28 (9)°in B. In each mol­ecule, the 1H-pyridin-2-one unit participates in inter­molecular N—H⋯O hydrogen bonding to another mol­ecule of the same type (A to A or B to B). The structure also displays π–π inter­actions between the pyridyl and the benzene rings of non-equivalent mol­ecules (viz., A to B and B to A). PMID:27555939

10. Viscosity, Second pVT-Virial Coefficient, and Diffusion of Pure and Mixed Small Alkanes CH4, C2H6, C3H8, n-C4H10, i-C4H10, n-C5H12, i-C5H12, and C(CH3)4 Calculated by Means of an Isotropic Temperature-Dependent Potential. I. Pure Alkanes

Zarkova, L.; Hohm, U.; Damyanova, M.

2006-09-01

Reference tables of second pVT-virial coefficients B(T ), viscosity η(T ), and self-diffusion ρD(T ) are given for all neat alkanes CnH2n+2, n <6, for temperatures T ⩽1200K starting at 100K for CH4, 150K for C2H6, and 180K for C3H8, n-C4H10, i-C4H10, n-C5H12, i-C5H12, and C(CH3)4. Restricting ourselves to low densities the thermophysical properties are calculated by means of an isotropic (n-6) Lennard-Jones temperature dependent potential (LJTDP). In this model the potential well depth ɛeff(T ) and the separation at minimum energy Rm(eff)(T) are explicitly temperature dependent, whereas the repulsive term n >12 is independent of T. The LJTDP has been used before in order to construct reference tables of thermophysical properties of neat gases [Zarkova and Hohm, J. Phys. Chem. Ref. Data 31, 183 (2002)] and binary mixtures [Zarkova, Hohm, and Damyanova, J. Phys. Chem. Ref. Data 32, 1591 (2003)]. However, those studies were restricted to atoms and globularly shaped nondipolar molecules. Here the approach is extended to elongated, not necessarily spherically symmetric, and in part slightly dipolar molecules. As in previous works the potential parameters ɛ(eff)(T), Rm(eff)(T), and n are determined by minimizing the root-mean-square deviation between calculated and experimentally obtained thermophysical properties B(T ), η(T ), ρD(T ), and the second acoustic virial coefficient β(T ) normalized to their experimental error. In extension of our previous efforts we present a thorough statistical analysis of the experimental input data which gives us the possibility to select primary data which could be used to build up a database.

11. Observation of the pi...H hydrogen-bonded ternary complex, (C(2)H(4))(2)H(2)O, using matrix isolation infrared spectroscopy.

PubMed

Thompson, Matthew G K; Lewars, Errol G; Parnis, J Mark

2005-10-27

FTIR absorption spectra of water-containing ethene:Ar matrices, with compositions of ethene up to 1:10 ethene:Ar, have been recorded. Systematically increasing the concentration of ethene reveals features in the spectra consistent with the known 1:1 ethene:water complex, which subsequently disappear on further increase in ethene concentration. At high concentrations of ethene, new features are observed at 3669 and 3585 cm(-1), which are red-shifted with respect to matrix-isolated nu(3) and nu(1) O-H stretching modes of water and the 1:1 ethene:water complex. These shifts are consistent with a pi...H interaction of a 2:1 ethene:water complex of the form (C(2)H(4)...H-O-H...C(2)H(4)). The analogous (C(2)D(4))(2)H(2)O complex shows little shifting from positions associated with (C(2)H(4))(2)H(2)O, while the (C(2)H(4))(2)D(2)O isotopomer shows large shifts to 2722.3 and 2617.2 cm(-1), having identical nu(3)(H(2)O)/nu(3)(D(2)O) and nu(1)(H(2)O)/nu(1)(D(2)O) values when compared with monomeric water isotopomers. Features at 3626.1 and 2666.2 cm(-1) are also observed and are attributed to (C(2)H(4))(2)HDO. DFT calculations at the B3LYP/6-311+G(d,p) level for each isotopomer are presented, and the predicted vibrational frequencies are directly compared with experimental values. The interaction energy for the formation of the 2:1 ethene:water complex from the 1:1 ethene:water complex is also presented.

12. U1h Superstructure

SciTech Connect

Glen Sykes

2000-11-01

The U1H Shaft Project is a design build subcontract to supply the U. S. Department of Energy (DOE) a 1,045 ft. deep, 20 ft. diameter, concrete lined shaft for unspecified purposes. The subcontract awarded to Atkinson Construction by Bechtel Nevada to design and construct the shaft for the DOE has been split into phases with portions of the work being released as dictated by available funding. The first portion released included the design for the shaft, permanent hoist, headframe, and collar arrangement. The second release consisted of constructing the shaft collar to a depth of 110 ft., the service entry, utility trenches, and installation of the temporary sinking plant. The temporary sinking plant included the installation of the sinking headframe, the sinking hoist, two deck winches, the shaft form, the sinking work deck, and temporary utilities required to sink the shaft. Both the design and collar construction were completed on schedule. The third release consisted of excavating and lining the shaft to the station depth of approximately 950 feet. Work is currently proceeding on this production sinking phase. At a depth of approximately 600 feet, Atkinson has surpassed production expectation and is more than 3 months ahead of schedule. Atkinson has employed the use of a Bobcat 331 excavator as the primary means of excavation. the shaft is being excavated entirely in an alluvial deposit with varying degrees of calcium carbonate cementation. Several more work packages are expected to be released in the near future. The remaining work packages include, construction of the shaft station a depth of 975 ft. and construction of the shaft sump to a depth of 1,045 ft., installation of the loading pocket and station steel and equipment, installation of the shaft steel and guides, installation of the shaft utilities, and installation of the permanent headframe, hoist, collar utilities, and facilities.

13. UV/vis, 1H, and 13C NMR spectroscopic studies to determine mangiferin pKa values.

PubMed

Gómez-Zaleta, Berenice; Ramírez-Silva, María Teresa; Gutiérrez, Atilano; González-Vergara, Enrique; Güizado-Rodríguez, Marisol; Rojas-Hernández, Alberto

2006-07-01

The acid constants of mangiferin (a natural xanthonoid) in aqueous solution were determined through an UV/vis spectroscopic study employing the SQUAD program as a computational tool. A NMR study complements the pK(a) values assignment and evidences a H-bridge presence on 1-C. The chemical model used was consistent with the experimental data obtained. The pK(a) values determined with this procedure were as follows: H(4)(MGF)=H(3)(MGF)(-)+H(+), pKa1 (6-H)=6.52+/-0.06; H(3)(MGF)(-)=H(2)(MGF)(2-)+H(+), pKa2 (3-H)=7.97+/-0.06; H(2)(MGF)(2-)=H(MGF)(3-)+H(+), pKa3 (7-H)=9.44+/-0.04; H(MGF)(3-)=(MGF)(4-)+H(+), pKa4 (1-H)=12.10+/-0.01; where it has been considered mangiferin C(19)H(18)O(11) as H(4)(MGF). Mangiferin UV/vis spectral behavior, stability study in aqueous solution as well as NMR spectroscopy studies: one-dimensional (1)H,(13)C, 2D correlated (1)H/(13)C performed by (g)-HSQC and (g)-HMBC methods; are also presented. pK(a) values determination of H(4)(MGF) in aqueous solution is a necessary contribution to subsequent pharmacokinetic study, and a step towards the understanding of its biological effects.

14. C3H4ArN2 1H-Imidazole - argon (1/1)

Demaison, J.

This document is part of Part 2 of Subvolume D 'Asymmetric Top Molecules' of Volume 29 'Molecular Constants Mostly from Microwave, Molecular Beam, and Sub-Doppler Laser Spectroscopy' of Landolt-Börnstein - Group II 'Molecules and Radicals'.

15. C3H4ArN2 1H-Pyrazole - argon (1/1)

Demaison, J.

This document is part of Part 2 of Subvolume D 'Asymmetric Top Molecules' of Volume 29 'Molecular Constants Mostly from Microwave, Molecular Beam, and Sub-Doppler Laser Spectroscopy' of Landolt-Börnstein - Group II 'Molecules and Radicals'.

16. Muon Capture on ^3H

Golak, Jacek; Skibiński, Roman; Witała, Henryk; Topolnicki, Kacper; Kamada, Hiroyuki; Nogga, Andreas; Marcucci, Laura E.

2017-01-01

The μ ^- + ^3H → ν _μ + n + n + n capture reaction is studied under full inclusion of final-state interactions with the AV18 nucleon-nucleon potential and the Urbana IX three-nucleon force. We employ the single nucleon weak current operator comprising the dominant relativistic corrections to obtain first estimates of the total capture rates based on realistic forces. Our results are compared with older theoretical predictions.

17. Theoretical exploration of hydrogen loss from Al3H9.

PubMed

Nold, Christopher P; Head, John D

2012-05-03

The Al(3)H(9) and Al(3)H(7) potential energy surfaces were explored using quantum chemistry calculations to investigate the H(2) loss mechanism from Al(3)H(9), which provide new insights into hydrogen production from bulk alane, [AlH(3)](x), a possible energy storage material. We present results of B3LYP/6-311++G(d,p) calculations for the various Al(3)H(9) and Al(3)H(7) optimized local minima and transition state structures along with some reaction pathways for their interconversion. We find the energy for Al(3)H(9) decomposition into Al(2)H(6) and AlH(3) is slightly lower than that for H(2) loss and Al(3)H(7) formation, but the calculations show that H(2) loss from Al(3)H(9) is a lower energy process than for losing hydrogen from either Al(2)H(6) or AlH(3). We found four transition state structures and reaction pathways for Al(3)H(9) → Al(3)H(7) + H(2), where the lowest energy activation barrier is around 25-73 kJ/mol greater than the experimental value for H(2) loss from bulk alane. Intrinsic reaction coordinate calculations show that the H(2) loss pathway involves considerable rearrangement of the H atom positions around a single Al center. Three of the pathways start with the formation of an AlH(3) moiety, which then enables a terminal H on the AlH(3) to get within 1.1 to 1.2 Å of a nearby bridging H atom. The bridging and terminal H atoms eventually combine to form H(2) and leave Al(3)H(9). One implication of these H(2) loss reaction pathways is that, since the H atoms in bulk alanes are all at bridging positions, if a similar H(2) loss mechanism were to apply to bulk alane, then H(2) loss would most likely occur on the bulk alane surface or at a defect site where there should be more terminal H atoms available for reaction with nearby bridging H atoms.

18. Effect of sequence of administration on the pharmacokinetic interaction between the anticholinergic drug biperiden and [3H]quinuclidinyl benzylate or [3H]N-methylscopolamine in rats.

PubMed

Ishizaki, J; Yokogawa, K; Nakashima, E; Takayasu, T; Ohshima, T; Ichimura, F

1998-02-01

In rats the pharmacokinetic interactions between the anticholinergic drug biperiden and [3H]quinuclidinyl benzylate ([3H]QNB) or [3H]N-methylscopolamine ([3H]NMS) is affected by the sequence in which the drugs are administered. Drug concentrations in various tissues were determined after intravenous administration of [3H]QNB or [3H]NMS (325 ng kg(-1)). Biperiden (6.4 mg kg(-1)) was administered either 5 min before, concomitantly with or 20 min after injection of [3H]QNB or [3H]NMS. When biperiden was administered concomitantly with or before [3H]QNB, distribution of [3H]QNB among the regions of the brain and other tissues was reduced; at 4 h the ratio of the distribution of [3H]QNB for experimental animals to that for control animals ranged from 0.15 to 0.9. When biperiden was administered after [3H]QNB, the distribution of [3H]QNB in the brain and other tissues was significantly higher than for the other two treatments (P < 0.01). However, for [3H]NMS the sequence of administration had no effect on the distribution of the drug in the brain and other tissues except for the kidney. In-vitro, in crude synaptosomal membranes, the amount of [3H]QNB at 2 h relative to the control concentration at equilibrium was 87% when biperiden was added before [3H]QNB and 56% when biperiden was added after [3H]QNB. In both instances the concentration of [3H]NMS reached equilibrium within 30 min. These findings suggest that the difference between the rate constant of association and dissociation at the possible site of action gives rise to the effect of the sequence of administration on the pharmacokinetic interaction.

19. Ion-neutral reaction of the C2H2N+ cation with C2H2: An experimental and theoretical study

Fathi, P.; Geppert, W. D.; Kaiser, A.; Ascenzi, D.

2016-03-01

The ion-neutral reactions of the C2H2N+ cation with C2H2 have been investigated using a Guided Ion Beam Mass Spectrometer (GIB-MS). The following ionic products were observed: CH3+, C2H2+, C2H3+, HNC+ /HCN+ , HCNH+, C3H+ , C2N+ , C3H3+, HCCN+ and C4H2N+ . Theoretical calculations have been carried out to propose reaction pathways leading to the observed products. These processes are of relevance for the generation of long chain nitrogen-containing species and they may be of interest for the chemistry of Titan's ionosphere or circumstellar envelopes.

20. Synthesis of stereospecifically deuterated desoxypodophyllotoxins and 1H-nmr assignment of desoxypodophyllotoxin

NASA Technical Reports Server (NTRS)

Pullockaran, A. J.; Kingston, D. G.; Lewis, N. G.

1989-01-01

[4 beta- 2H1]Desoxypodophyllotoxin [3], [4 alpha- 2H1]desoxypodophyllotoxin [4], and [4, 4- 2 H2]desoxypodophyllotoxin [9] were prepared from podophyllotoxin [1] via its chloride [5]. A complete assignment of the 1H-nmr spectrum of desoxypodophyllotoxin [2] was made on the basis of the spectra of the deuterated compounds [3] and [4].

1. Immobilization of Ag(i) into a metal-organic framework with -SO3H sites for highly selective olefin-paraffin separation at room temperature.

PubMed

Chang, Ganggang; Huang, Minhui; Su, Ye; Xing, Huabin; Su, Baogen; Zhang, Zhiguo; Yang, Qiwei; Yang, Yiwen; Ren, Qilong; Bao, Zongbi; Chen, Banglin

2015-02-18

Introduction of Ag(i) ions into a sulfonic acid functionalized MOF ((Cr)-MIL-101-SO3H) significantly enhances its interactions with olefin double bonds, leading to its much higher selectivities for the separation of C2H4-C2H6 and C3H6-C3H8 at room temperature over the original (Cr)-MIL-101-SO3H and other adsorbents at room temperature.

2. Dynamically biased statistical model for the ortho/para conversion in the H2+H3+ --> H3++ H2 reaction

Gómez-Carrasco, Susana; González-Sánchez, Lola; Aguado, Alfredo; Sanz-Sanz, Cristina; Zanchet, Alexandre; Roncero, Octavio

2012-09-01

In this work we present a dynamically biased statistical model to describe the evolution of the title reaction from statistical to a more direct mechanism, using quasi-classical trajectories (QCT). The method is based on the one previously proposed by Park and Light [J. Chem. Phys. 126, 044305 (2007), 10.1063/1.2430711]. A recent global potential energy surface is used here to calculate the capture probabilities, instead of the long-range ion-induced dipole interactions. The dynamical constraints are introduced by considering a scrambling matrix which depends on energy and determine the probability of the identity/hop/exchange mechanisms. These probabilities are calculated using QCT. It is found that the high zero-point energy of the fragments is transferred to the rest of the degrees of freedom, what shortens the lifetime of H_5^+ complexes and, as a consequence, the exchange mechanism is produced with lower proportion. The zero-point energy (ZPE) is not properly described in quasi-classical trajectory calculations and an approximation is done in which the initial ZPE of the reactants is reduced in QCT calculations to obtain a new ZPE-biased scrambling matrix. This reduction of the ZPE is explained by the need of correcting the pure classical level number of the H_5^+ complex, as done in classical simulations of unimolecular processes and to get equivalent quantum and classical rate constants using Rice-Ramsperger-Kassel-Marcus theory. This matrix allows to obtain a ratio of hop/exchange mechanisms, α(T), in rather good agreement with recent experimental results by Crabtree et al. [J. Chem. Phys. 134, 194311 (2011), 10.1063/1.3587246] at room temperature. At lower temperatures, however, the present simulations predict too high ratios because the biased scrambling matrix is not statistical enough. This demonstrates the importance of applying quantum methods to simulate this reaction at the low temperatures of astrophysical interest.

3. Hydrogen dynamics in soil organic matter as determined by 13C and 2H labeling experiments

Paul, Alexia; Hatté, Christine; Pastor, Lucie; Thiry, Yves; Siclet, Françoise; Balesdent, Jérôme

2016-12-01

Understanding hydrogen dynamics in soil organic matter is important to predict the fate of 3H in terrestrial environments. One way to determine hydrogen fate and to point out processes is to examine the isotopic signature of the element in soil. However, the non-exchangeable hydrogen isotopic signal in soil is complex and depends on the fate of organic compounds and microbial biosyntheses that incorporate water-derived hydrogen. To decipher this complex system and to understand the close link between hydrogen and carbon cycles, we followed labeled hydrogen and labeled carbon throughout near-natural soil incubations. We performed incubation experiments with three labeling conditions: 1 - 13C2H double-labeled molecules in the presence of 1H2O; 2 - 13C-labeled molecules in the presence of 2H2O; 3 - no molecule addition in the presence of 2H2O. The preservation of substrate-derived hydrogen after 1 year of incubation (ca. 5 % in most cases) was lower than the preservation of substrate-derived carbon (30 % in average). We highlighted that 70 % of the C-H bonds are broken during the degradation of the molecule, which permits the exchange with water hydrogen. Added molecules are used more for trophic resources. The isotopic composition of the non-exchangeable hydrogen was mainly driven by the incorporation of water hydrogen during microbial biosynthesis. It is linearly correlated with the amount of carbon that is degraded in the soil. The quantitative incorporation of water hydrogen in bulk material and lipids demonstrates that non-exchangeable hydrogen exists in both organic and mineral-bound forms. The proportion of the latter depends on soil type and minerals. This experiment quantified the processes affecting the isotopic composition of non-exchangeable hydrogen, and the results can be used to predict the fate of tritium in the ecosystem or the water deuterium signature in organic matter.

4. An oxazolo[3,2-b]indazole route to 1H-indazolones.

PubMed

Oakdale, James S; Solano, Danielle M; Fettinger, James C; Haddadin, Makhluf J; Kurth, Mark J

2009-07-02

The novel heterocycle 2,3-dihydrooxazolo[3,2-b]indazole has been synthesized and utilized to provide easy access to 1H-indazolones, particularly the previously unreported 2-(2-alkoxyethyl)-1H-indazol-3(2H)-ones. Mechanistic as well as optimization and reaction scope studies are reported.

5. 3-Benzyl-6-bromo-1H-imidazo[4,5-b]pyridin-2(3H)-one

PubMed Central

Kandri Rodi, Youssef; Haoudi, Amal; Capet, Frédéric; Mazzah, Ahmed; Essassi, El Mokhtar; El Ammari, Lahcen

2013-01-01

The fused imidazole and pyridine rings in the title compound, C13H10BrN3O, are linked to a benzyl group. The fused ring system is essentially planar, the largest deviation from the mean plane being 0.006 (2) Å. The phenyl ring is not coplanar with the fused ring system, as indicated by the dihedral angle of 67.04 (12)°. In the crystal, mol­ecules are linked by pairs of N—H⋯O hydrogen bonds, forming inversion dimers. PMID:23795120

6. Natural-abundance solid-state 2H NMR spectroscopy at high magnetic field.

PubMed

Aliev, Abil E; Mann, Sam E; Iuga, Dinu; Hughes, Colan E; Harris, Kenneth D M

2011-06-09

High-resolution solid-state (2)H NMR spectroscopy provides a method for measuring (1)H NMR chemical shifts in solids and is advantageous over the direct measurement of high-resolution solid-state (1)H NMR spectra, as it requires only the application of routine magic angle sample spinning (MAS) and routine (1)H decoupling methods, in contrast to the requirement for complex pulse sequences for homonuclear (1)H decoupling and ultrafast MAS in the case of high-resolution solid-state (1)H NMR. However, a significant obstacle to the routine application of high-resolution solid-state (2)H NMR is the very low natural abundance of (2)H, with the consequent problem of inherently low sensitivity. Here, we explore the feasibility of measuring (2)H MAS NMR spectra of various solids with natural isotopic abundances at high magnetic field (850 MHz), focusing on samples of amino acids, peptides, collagen, and various organic solids. The results show that high-resolution solid-state (2)H NMR can be used successfully to measure isotropic (1)H chemical shifts in favorable cases, particularly for mobile functional groups, such as methyl and -N(+)H(3) groups, and in some cases phenyl groups. Furthermore, we demonstrate that routine (2)H MAS NMR measurements can be exploited for assessing the relative dynamics of different functional groups in a molecule and for assessing whole-molecule motions in the solid state. The magnitude and field-dependence of second-order shifts due to the (2)H quadrupole interaction are also investigated, on the basis of analysis of simulated and experimental (1)H and (2)H MAS NMR spectra of fully deuterated and selectively deuterated samples of the α polymorph of glycine at two different magnetic field strengths.

7. HIST1H2AA — EDRN Public Portal

Cancer.gov

HIST1H2AA, a member of the histone 2A family, is a core component of the nucleosome. The nucleosome is a histone octamer containing two molecules each of H2A, H2B, H3 and H4 assembled in one H3-H4 heterotetramer and two H2A-H2B heterodimers. Nucleosomes wrap and compact DNA into chromatin, limiting DNA accessibility to the cellular machineries which require DNA as a template (the octamer wraps approximately 147 bp of DNA). Histones thereby play a central role in transcription regulation, DNA repair, DNA replication and chromosomal stability. DNA accessibility is regulated via a complex set of post-translational modifications of histones, also called histone code, and nucleosome remodeling. The HIST1H2AA gene is intronless and encodes a member of the histone H2A family. Transcripts from this gene contain a palindromic termination element.

8. Investigations of intramolecular hydrogen bonding in three types of Schiff bases by 2H and 3H NMR isotope effects.

PubMed

Schilf, Wojciech; Bloxsidge, James P; Jones, John R; Lu, Shui-Yu

2004-06-01

Hydrogen bonding within the structures of three Schiff bases (1-3), obtained by condensation of 4-methoxy-, 5-methoxy- and 4,6-dimethoxysalicylaldehyde with methylamine, was investigated by measuring deuterium and tritium NMR isotope effects. The primary deuterium and tritium isotope effects (delta(XH)-delta(XD/T)) and secondary one-bond nitrogen deuterium effect appear to be very useful parameters for defining the character of intramolecular hydrogen bonds. The tritium isotope effects were also determined for nitrogen-hydrogen one-bond coupling constants for both 4-methoxy and 4,6-dimethoxy derivatives. These parameters are seen to be highly sensitive to hydrogen bond characteristics and can be used to distinguish localized and tautomeric hydrogen bonds.

9. The Photon Polarization Parameter of 2H(n, γ)3H reaction with Inclusion of the Electric Quadrupole Contribution

2014-09-01

We use effective field theory (EFT) for the calculation of neutron—deuteron radiative capture at very low energies. We present here the use of EFT to calculate a low-energy photo-nuclear observable in three-body systems, the photon polarization parameter and fore—aft asymmetry at thermal neutron energies up to next-to-next to leading order (N2LO), with inclusion of the electric quadrupole contribution. The photon polarization parameter in total is found to be Rc = -0.421 ± 0.003 and is in good agreement with the other modern theoretical calculations based on modern nucleon—nucleon potentials. In comparison with our previous work, a satisfactory agreement with the available experimental data is found by inclusion of the electric quadrupole contribution.

10. Environmental, trophic, and ecological factors influencing bone collagen δ2H

Topalov, Katarina; Schimmelmann, Arndt; David Polly, P.; Sauer, Peter E.; Lowry, Mark

2013-06-01

Organic deuterium/hydrogen stable isotope ratios (i.e., 2H/1H, expressed as δ2H value in ‰) in animal tissues are related to the 2H/1H in diet and ingested water. Bone collagen preserves the biochemical 2H/1H isotopic signal in the δ2H value of collagen's non-exchangeable hydrogen. Therefore, δ2H preserved in bone collagen has the potential to constrain environmental and trophic conditions, which is of interest to researchers studying of both living and fossil vertebrates. Our data examine the relationship of δ2H values of collagen with geographic variation in δ2H of meteoric waters, with local variations in the ecology and trophic level of species, and with the transition from mother's milk to adult diet. Based on 97 individuals from 22 marine and terrestrial vertebrates (predominately mammals), we found the relationships of collagen δ2H to both geographic variation in meteoric water δ2H (R2 = 0.55) and to δ15N in bone collagen (R2 = 0.17) statistically significant but weaker than previously reported. The second strongest control on collagen δ2H in our data is dietary, with nearly 50 percent of the variance in δ2H explained by trophic level (R2 = 0.47). Trophic level effects potentially confound the local meteoric signal if not held constant: herbivores tend to have the lowest δ2H values, omnivores have intermediate ones, and carnivores have the highest values. Body size (most likely related to mass-specific metabolic rates) has a strong influence on collagen δ2H (R2 = 0.30), by causing greater sensitivity in smaller animals to seasonal climate variations and/or high evapotranspiration leading to 2H-enrichment in tissues. In marine mammals weaning produces a dramatic effect on collagen δ2H with adult values being universally higher than pup values (R2 = 0.79). Interestingly, the shift in δ15N at weaning is downward, even though normally hydrogen and nitrogen isotope ratios are positively correlated with one another in respect to trophic level. Our

11. Di-n-butyltin(IV) Complexes Derived from Heterocyclic β-diketones and N-Phthaloyl Amino Acids: Preparation, Biological Evaluation, Structural Elucidation Based upon Spectral [IR, NMR (1H, 13C, 19F and 119Sn)] Studies

PubMed Central

Verma, Shashi; Gaurb, R. B.; Sharma, R. R.

2005-01-01

Stable, six coordinated Bu2SnLA type complexes have been prepared [where LH = RCOC:C(OH)N(C6 H5)N:CCH3; R = -4-F-C6H4-(L1H), R = -4-Cl-C6H4-(L2H), R= -4-Br-C6H4-(L3H), R=-CF3(L4H) and AH = C(O)C6 H4 C(O)NCHR'COOH; R'= -H(A1H), -CH3(A2H), -CH(CH3)2(A3H)] by the interaction of 1:1:1 molar ratios of di-n-butyltin(IV) dichloride with corresponding organic moieties in refluxing benzene using two moles of Et3N as a base. In these complexes LH and AH behave as bidentate and coordination is taking place through oxygen, this is inferred from IR and 13C NMR studies. These complexes possess tin atoms in skew trapezoidal bipyramidal geometry with the C-Sn-C angles ranging from 149.88° to 156.84°. Some of these complexes with their corresponding organic moieties (LH, AH) were tested for their antimicrobial activities. PMID:18365100

12. Di-n-butyltin(IV) complexes derived from heterocyclic beta-diketones and N-phthaloyl amino acids: preparation, biological evaluation, structural elucidation based upon spectral [IR, NMR (1H, 13C, 19F and 119Sn)] studies.

PubMed

Joshi, Anurag; Verma, Shashi; Gaurb, R B; Sharma, R R

2005-01-01

Stable, six coordinated Bu(2)SnLA type complexes have been prepared [where LH = RCOC:C(OH)N(C(6) H(5))N:CCH(3); R = -4-F-C(6)H(4)-(L(1)H), R = -4-Cl-C(6)H(4)-(L(2)H), R= -4-Br-C(6)H(4)-(L(3)H), R=-CF(3)(L(4)H) and AH = C(O)C(6) H(4) C(O)NCHR'COOH; R'= -H(A(1)H), -CH(3)(A(2)H), -CH(CH(3))(2)(A(3)H)] by the interaction of 1:1:1 molar ratios of di-n-butyltin(IV) dichloride with corresponding organic moieties in refluxing benzene using two moles of Et(3)N as a base. In these complexes LH and AH behave as bidentate and coordination is taking place through oxygen, this is inferred from IR and (13)C NMR studies. These complexes possess tin atoms in skew trapezoidal bipyramidal geometry with the C-Sn-C angles ranging from 149.88( degrees ) to 156.84( degrees ). Some of these complexes with their corresponding organic moieties (LH, AH) were tested for their antimicrobial activities.

13. Thermal decomposition of (UO2)O2(H2O)2·2H2O: Influence on structure, microstructure and hydrofluorination

Thomas, R.; Rivenet, M.; Berrier, E.; de Waele, I.; Arab, M.; Amaraggi, D.; Morel, B.; Abraham, F.

2017-01-01

The thermal decomposition of uranyl peroxide tetrahydrate, (UO2)O2(H2O)2.2H2O, was studied by combining high temperature powder X-ray diffraction, scanning electron microscopy, thermal analyses and spectroscopic techniques (Raman, IR and 1H NMR). In situ analyses reveal that intermediates and final uranium oxides obtained upon heating are different from that obtained after cooling at room temperature and that the uranyl precursor used to synthesize (UO2)O2(H2O)2·2H2O, sulfate or nitrate, has a strong influence on the peroxide thermal behavior and morphology. The decomposition of (UO2)O2(H2O)2·2H2O ex sulfate is pseudomorphic and leads to needle-like shaped particles of metastudtite, (UO2)O2(H2O)2, and UO3-x(OH)2x·zH2O, an amorphous phase found in air in the following of (UO2)O2(H2O)2 dehydration. (UO2)O2(H2O)2·2H2O and the compounds resulting from its thermal decomposition are very reactive towards hydrofluorination as long as their needle-like morphology is kept.

14. catena-Poly[[[aqua-chlorido-manganese(II)]-bis-[μ-1,1'-(oxydi-p-phenyl-ene)di-1H-imidazole-κN:N

PubMed

Mu, Xiao-Long

2011-01-15

The title coordination polymer, {[MnCl(C(18)H(14)N(4)O)(2)(H(2)O)]Cl·C(3)H(7)NO·H(2)O}(n), obtained by the solvothermal reaction of BIDPE and manganese(II) salt in H(2)O/DMF (DMF is dimethyl-formamide), is composed of a chain of [Mn(2)(BIDPE)(2)] [BIDPE is 1,1'-(oxydi-p-phenyl-ene)di-1H-imidazole] metallocyclic rings that exhibit inversion symmetry. The coordination about the Mn(II) ions is distorted octahedral with a MnClN(4)O coordination set. In the crystal, the polymeric chains are linked by O-H⋯Cl hydrogen bonds, forming a two-dimensional network parallel to (100). A number of C-H⋯Cl and C-H⋯O inter-actions are also present.

15. Adrenergic receptor and catecholamine distribution in rat cerebral cortex: binding studies with [3H]prazosin, [3H]idazoxan and [3H]dihydroalprenolol.

PubMed

Diop, L; Brière, R; Grondin, L; Reader, T A

1987-02-03

The tritiated adrenergic antagonists [3H]dihydroalprenolol ([3H]DHA; beta-receptors), [3H]prazosin ([3H]PRZ; alpha 1-receptors), and [3H]idazoxan ([3H]IDA; alpha 2-receptors) were used to determine the distribution of these sites in 5 defined areas of the adult rat cerebral cortex. The highest density of [3H]PRZ binding was found in the prefrontal cortex, with a lower and homogeneous distribution for the frontal, parietal, occipital and temporal areas. The [3H]IDA binding sites were fairly uniform for all areas, except for the temporal cortex where it was very dense. In contrast, beta-adrenoceptors labelled by [3H]DHA were very homogeneous for all the regions examined. The functional significance of the distribution of alpha 1, alpha 2 and beta-adrenoceptors is discussed in relation to the catecholamine innervation and monoamine contents measured by high performance liquid chromatography.

16. Dehydrocoupling of dimethylamine borane catalyzed by Rh(PCy3)2H2Cl.

PubMed

Sewell, Laura J; Huertos, Miguel A; Dickinson, Molly E; Weller, Andrew S; Lloyd-Jones, Guy C

2013-04-15

The Rh(III) species Rh(PCy3)2H2Cl is an effective catalyst (2 mol %, 298 K) for the dehydrogenation of H3B·NMe2H (0.072 M in 1,2-F2C6H4 solvent) to ultimately afford the dimeric aminoborane [H2BNMe2]2. Mechanistic studies on the early stages in the consumption of H3B·NMe2H, using initial rate and H/D exchange experiments, indicate possible dehydrogenation mechanisms that invoke turnover-limiting N-H activation, which either precedes or follows B-H activation, to form H2B═NMe2, which then dimerizes to give [H2BNMe2]2. An additional detail is that the active catalyst Rh(PCy3)2H2Cl is in rapid equilibrium with an inactive dimeric species, [Rh(PCy3)H2Cl]2. The reaction of Rh(PCy3)2H2Cl with [Rh(PCy3)H2(H2)2][BAr(F)4] forms the halide-bridged adduct [Rh(PCy3)2H2(μ-Cl)H2(PCy3)2Rh][BAr(F)4] (Ar(F) = 3,5-(CF3)2C6H3), which has been crystallographically characterized. This dinuclear cation dissociates on addition of H3B·NMe2H to re-form Rh(PCy3)2H2Cl and generate [Rh(PCy3)2H2(η(2)-H3B·NMe2H)][BAr(F)4]. The fate of the catalyst at low catalyst loadings (0.5 mol %) is also addressed, with the formation of an inactive borohydride species, Rh(PCy3)2H2(η(2)-H2BH2), observed. On addition of H3B·NMe2H to Ir(PCy3)2H2Cl, the Ir congener Ir(PCy3)2H2(η(2)-H2BH2) is formed, with concomitant generation of the salt [H2B(NMe2H)2]Cl.

17. Galápagos hydroclimate of the Common Era from paired microalgal and mangrove biomarker 2H/1H values

Nelson, Daniel B.; Sachs, Julian P.

2016-03-01

Tropical maritime precipitation affects global atmospheric circulation, influencing storm tracks and the size and location of subtropical deserts. Paleoclimate evidence suggests centuries-long changes in rainfall in the tropical Pacific over the past 2,000 y, but these remain poorly characterized across most of the ocean where long, continuous proxy records capable of resolving decadal-to-centennial climate changes are still virtually nonexistent despite substantial efforts to develop them. Here we apply a new climate proxy based on paired hydrogen isotope ratios from microalgal and mangrove-derived sedimentary lipids in the Galápagos to reconstruct maritime precipitation changes during the Common Era. We show that increased rainfall during the Little Ice Age (LIA) (∼1400-1850 CE) was likely caused by a southward migration of the Intertropical Convergence Zone (ITCZ), and that this shift occurred later than previously recognized, coeval with dynamically linked precipitation changes in South America and the western tropical Pacific. Before the LIA, we show that drier conditions at the onset of the Medieval Warm Period (∼800-1300 CE) and wetter conditions ca. 2 ka were caused by changes in the El Niño/Southern Oscillation (ENSO). Collectively, the large natural variations in tropical rainfall we detect, each linked to a multicentury perturbation of either ENSO-like variability or the ITCZ, imply a high sensitivity of tropical Pacific rainfall to climate forcings.

18. Galápagos hydroclimate of the Common Era from paired microalgal and mangrove biomarker 2H/1H values.

PubMed

Nelson, Daniel B; Sachs, Julian P

2016-03-29

Tropical maritime precipitation affects global atmospheric circulation, influencing storm tracks and the size and location of subtropical deserts. Paleoclimate evidence suggests centuries-long changes in rainfall in the tropical Pacific over the past 2,000 y, but these remain poorly characterized across most of the ocean where long, continuous proxy records capable of resolving decadal-to-centennial climate changes are still virtually nonexistent despite substantial efforts to develop them. Here we apply a new climate proxy based on paired hydrogen isotope ratios from microalgal and mangrove-derived sedimentary lipids in the Galápagos to reconstruct maritime precipitation changes during the Common Era. We show that increased rainfall during the Little Ice Age (LIA) (∼1400-1850 CE) was likely caused by a southward migration of the Intertropical Convergence Zone (ITCZ), and that this shift occurred later than previously recognized, coeval with dynamically linked precipitation changes in South America and the western tropical Pacific. Before the LIA, we show that drier conditions at the onset of the Medieval Warm Period (∼800-1300 CE) and wetter conditions ca. 2 ka were caused by changes in the El Niño/Southern Oscillation (ENSO). Collectively, the large natural variations in tropical rainfall we detect, each linked to a multicentury perturbation of either ENSO-like variability or the ITCZ, imply a high sensitivity of tropical Pacific rainfall to climate forcings.

19. Galápagos hydroclimate of the Common Era from paired microalgal and mangrove biomarker 2H/1H values

PubMed Central

Sachs, Julian P.

2016-01-01

Tropical maritime precipitation affects global atmospheric circulation, influencing storm tracks and the size and location of subtropical deserts. Paleoclimate evidence suggests centuries-long changes in rainfall in the tropical Pacific over the past 2,000 y, but these remain poorly characterized across most of the ocean where long, continuous proxy records capable of resolving decadal-to-centennial climate changes are still virtually nonexistent despite substantial efforts to develop them. Here we apply a new climate proxy based on paired hydrogen isotope ratios from microalgal and mangrove-derived sedimentary lipids in the Galápagos to reconstruct maritime precipitation changes during the Common Era. We show that increased rainfall during the Little Ice Age (LIA) (∼1400–1850 CE) was likely caused by a southward migration of the Intertropical Convergence Zone (ITCZ), and that this shift occurred later than previously recognized, coeval with dynamically linked precipitation changes in South America and the western tropical Pacific. Before the LIA, we show that drier conditions at the onset of the Medieval Warm Period (∼800–1300 CE) and wetter conditions ca. 2 ka were caused by changes in the El Niño/Southern Oscillation (ENSO). Collectively, the large natural variations in tropical rainfall we detect, each linked to a multicentury perturbation of either ENSO-like variability or the ITCZ, imply a high sensitivity of tropical Pacific rainfall to climate forcings. PMID:26976574

20. [3H]Ethynylbicycloorthobenzoate ([3H]EBOB) binding in recombinant GABAA receptors.

PubMed

Yagle, Monica A; Martin, Michael W; de Fiebre, Christopher M; de Fiebre, NancyEllen C; Drewe, John A; Dillon, Glenn H

2003-12-01

Ethynylbicycloorthobenzoate (EBOB) is a recently developed ligand that binds to the convulsant site of the GABAA receptor. While a few studies have examined the binding of [3H]EBOB in vertebrate brain tissue and insect preparations, none have examined [3H]EBOB binding in preparations that express known configurations of the GABAA receptor. We have thus examined [3H]EBOB binding in HEK293 cells stably expressing human alpha1beta2gamma2 and alpha2beta2gamma2 GABAA receptors, and the effects of CNS convulsants on its binding. The ability of the CNS convulsants to displace the prototypical convulsant site ligand, [35S]TBPS, was also assessed. Saturation analysis revealed [3H]EBOB binding at a single site, with a K(d) of approximately 9 nM in alpha1beta2gamma2 and alpha2beta2gamma2 receptors. Binding of both [3H]EBOB and [35S]TBPS was inhibited by dieldrin, lindane, tert-butylbicycloorthobenzoate (TBOB), PTX, TBPS, and pentylenetetrazol (PTZ) at one site in a concentration-dependent fashion. Affinities were in the high nM to low microM range for all compounds except PTZ (low mM range), and the rank order of potency for these convulsants to displace [3H]EBOB and [35S]TBPS was the same. Low [GABA] stimulated [3H]EBOB binding, while higher [GABA] (greater than 10 microM) inhibited [3H]EBOB binding. Overall, our data demonstrate that [3H]EBOB binds to a single, high affinity site in alpha1beta2gamma2 and alpha2beta2gamma2 GABAA receptors, and modulation of its binding is similar to that seen with [35S]TBPS. [3H]EBOB has a number of desirable traits that may make it preferable to [35S]TBPS for analysis of the convulsant site of the GABAA receptor.

1. Ultrasonic degradation of 1-H-benzotriazole in water.

PubMed

Zúñiga-Benítez, Henry; Soltan, Jafar; Peñuela, Gustavo

2014-01-01

2. FTIR, magnetic, 1H NMR spectral and thermal studies of some chelates of caproic acid: Inhibitory effect on different kinds of bacteria

Refat, Moamen S.; El-Korashy, Sabry A.; Kumar, Deo Nandan; Ahmed, Ahmed S.

2008-06-01

A convenient method for the preparation of complexes of the Cr 3+, Mn 2+, Fe 3+, Co 2+, Ni 2+, Zn 2+, ZrO 2+, UO 22+, Zr 4+ and Th 4+ ions with caproic acid (Hcap) is reported and this has enabled 10 complexes of caproate anion to be formulated: [Cr(cap) 3]·5H 2O, [Mn(cap) 2(H 2O) 2], [Fe(cap) 3]·12H 2O, [Co(cap) 2(H 2O) 2]·4H 2O, [Ni(cap) 2(H 2O) 2]·3H 2O, [Zn(cap) 2], [ZrO(cap) 2]·3H 2O, [UO 2(cap)(NO 3)], [Zr(cap) 2(Cl) 2] and [Th(cap) 4]. These new complexes were synthesized and characterized by elemental analysis, molar conductivity, magnetic measurements, spectral methods (mid infrared, 1H NMR and UV-vis spectra) and simultaneous thermal analysis (TG and DTG) techniques. It has been found from the elemental analysis as well as thermal studies that the caproate ligand behaves as bidentate ligand and forming chelates with 1:1 (metal:ligand) stoichiometry for UO 22+, 1:2 for (Mn 2+, Co 2+, Ni 2+, Zn 2+, ZrO 2+ and Zr 4+), 1:3 stoichiometry for (Cr 3+ and Fe 3+) and 1:4 for Th 4+ caproate complexes, respectively, as bidentate chelating. The molar conductance measurements proved that the caproate complexes are non-electrolytes. The kinetic thermodynamic parameters such as: E*, Δ H*, Δ S* and Δ G* are estimated from the DTG curves. The antibacterial activity of the caproic acid and their complexes was evaluated against some gram positive/negative bacteria.

3. Avian influenza virus hemagglutinins H2, H4, H8, and H14 support a highly pathogenic phenotype

PubMed Central

Veits, Jutta; Weber, Siegfried; Stech, Olga; Breithaupt, Angele; Gräber, Marcus; Gohrbandt, Sandra; Bogs, Jessica; Hundt, Jana; Teifke, Jens P.; Mettenleiter, Thomas C.; Stech, Jürgen

2012-01-01

High-pathogenic avian influenza viruses (HPAIVs) evolve from low-pathogenic precursors specifying the HA serotypes H5 or H7 by acquisition of a polybasic HA cleavage site. As the reason for this serotype restriction has remained unclear, we aimed to distinguish between compatibility of a polybasic cleavage site with H5/H7 HA only and unique predisposition of these two serotypes for insertion mutations. To this end, we introduced a polybasic cleavage site into the HA of several low-pathogenic avian strains with serotypes H1, H2, H3, H4, H6, H8, H10, H11, H14, or H15, and rescued HA reassortants after cotransfection with the genes from either a low-pathogenic H9N2 or high-pathogenic H5N1 strain. Oculonasal inoculation with those reassortants resulted in varying pathogenicity in chicken. Recombinants containing the engineered H2, H4, H8, or H14 in the HPAIV background were lethal and exhibited i.v. pathogenicity indices of 2.79, 2.37, 2.85, and 2.61, respectively, equivalent to naturally occurring H5 or H7 HPAIV. Moreover, the H2, H4, and H8 reassortants were transmitted to some contact chickens. The H2 reassortant gained two mutations in the M2 proton channel gate region, which is affected in some HPAIVs of various origins. Taken together, in the presence of a polybasic HA cleavage site, non-H5/H7 HA can support a highly pathogenic phenotype in the appropriate viral background, indicating requirement for further adaptation. Therefore, the restriction of natural HPAIV to serotypes H5 and H7 is likely a result of their unique predisposition for acquisition of a polybasic HA cleavage site. PMID:22308331

4. Thermodynamic Modeling of the SRS Evaporators: Part II. The 3H System

SciTech Connect

Jantzen, C.M.

2001-10-02

Accumulations of two solid phases have formed scale deposits in the Savannah River Site 2H Evaporator system since late 1996. The aluminosilicate scale deposits caused the evaporator pot to become inoperable in October 1999. Accumulations of the diuranate phase have caused criticality concerns in the SRS 2H Evaporator. In order to ensure that similar deposits are not and will not form in the SRS 3H Evaporator, thermodynamically derived activity diagrams specific to the feeds processed from Tanks 30 and 32 are evaluated in this report.

5. Vicinal 1H-1H NMR coupling constants from density functional theory as reliable tools for stereochemical analysis of highly flexible multichiral center molecules.

PubMed

López-Vallejo, Fabian; Fragoso-Serrano, Mabel; Suárez-Ortiz, Gloria Alejandra; Hernández-Rojas, Adriana C; Cerda-García-Rojas, Carlos M; Pereda-Miranda, Rogelio

2011-08-05

A protocol for stereochemical analysis, based on the systematic comparison between theoretical and experimental vicinal (1)H-(1)H NMR coupling constants, was developed and applied to a series of flexible compounds (1-8) derived from the 6-heptenyl-5,6-dihydro-2H-pyran-2-one framework. The method included a broad conformational search, followed by geometry optimization at the DFT B3LYP/DGDZVP level, calculation of the vibrational frequencies, thermochemical parameters, magnetic shielding tensors, and the total NMR spin-spin coupling constants. Three scaling factors, depending on the carbon atom hybridizations, were found for the (1)H-C-C-(1)H vicinal coupling constants: f((sp3)-(sp3)) = 0.910, f((sp3)-(sp2)) = 0.929, and f((sp2)-(sp2))= 0.977. A remarkable correlation between the theoretical (J(pre)) and experimental (1)H-(1)H NMR (J(exp)) coupling constants for spicigerolide (1), a cytotoxic natural product, and some of its synthetic stereoisomers (2-4) demonstrated the predictive value of this approach for the stereochemical assignment of highly flexible compounds containing multiple chiral centers. The stereochemistry of two natural 6-heptenyl-5,6-dihydro-2H-pyran-2-ones (14 and 15) containing diverse functional groups in the heptenyl side chain was also analyzed by application of this combined theoretical and experimental approach, confirming its reliability. Additionally, a geometrical analysis for the conformations of 1-8 revealed that weak hydrogen bonds substantially guide the conformational behavior of the tetraacyloxy-6-heptenyl-2H-pyran-2-ones.

6. 1H-detected 1H- 1H correlation spectroscopy of a stereo-array isotope labeled amino acid under fast magic-angle spinning

Takahashi, Hiroki; Kainosho, Masatsune; Akutsu, Hideo; Fujiwara, Toshimichi

2010-04-01

The combined use of selective deuteration, stereo-array isotope labeling (SAIL), and fast magic-angle spinning effectively suppresses the 1H-1H dipolar couplings in organic solids. This method provided the high-field 1H NMR linewidths comparable to those achieved by combined rotation and multiple-pulse spectroscopy. This technique was applied to two-dimensional 1H-detected 1H-1H polarization transfer CHH experiments of valine. The signal sensitivity for the 1H-detected CHH experiments was greater than that for the 13C-detected 1H-1H polarization transfer experiments by a factor of 2-4. We obtained the 1H-1H distances in SAIL valine by CHH experiments with an accuracy of about 0.2 Å by using a theory developed for 1H-1H polarization transfer in 13C-labeled organic compounds.

7. Antifungal properties of wheat histones (H1-H4) and purified wheat histone H1

Technology Transfer Automated Retrieval System (TEKTRAN)

Wheat (Triticum sp.) histones H1, H2, H3, and H4 were extracted. H1 was further purified. Their activities against fungi with varying degrees of wheat pathogenicity were determined. They included Aspergillus flavus, A. fumigatus, A. niger, F. oxysporum, F. verticillioides, F. solani, F. graminearu...

8. Low-lying states of Li 3H: Is there an ion-pair minimum?

Talbi, Dahbia; Saxon, Roberta P.

1989-05-01

The 1 1A', 1 1A″, 1 3A', and 1 3A″ states of Li 3H have been investigated at the MCSCF/SOCI level. The global minimum is a planar conformation of 1A' symmetry. A local minimum on the same potential surface at a C 3v pyramidal geometry, of mixed ion-pair and covalent character, is found at a relative energy of 20.30 kcal/mol. The barrier height for isomerization is predicted to be 1.3 kcal/mol. The correlation diagram linking states of Li 3H to those of Li 3 + H, LiH + Li 2 and Li 2H + Li is presented.

9. Characterization of heroin samples by 1H NMR and 2D DOSY 1H NMR.

PubMed

Balayssac, Stéphane; Retailleau, Emmanuel; Bertrand, Geneviève; Escot, Marie-Pierre; Martino, Robert; Malet-Martino, Myriam; Gilard, Véronique

2014-01-01

Twenty-four samples of heroin from different illicit drug seizures were analyzed using proton Nuclear Magnetic Resonance ((1)H NMR) and two-dimensional diffusion-ordered spectroscopy (2D DOSY) (1)H NMR. A careful assignment and quantification of (1)H signals enabled a comprehensive characterization of the substances present in the samples investigated: heroin, its main related impurities (6-acetylmorphine, acetylcodeine, morphine, noscapine and papaverine) and cutting agents (caffeine and acetaminophen in nearly all samples as well as lactose, lidocaine, mannitol, piracetam in one sample only), and hence to establish their spectral signatures. The good agreement between the amounts of heroin, noscapine, caffeine and acetaminophen determined by (1)H NMR and gas chromatography, the reference method in forensic laboratories, demonstrates the validity of the (1)H NMR technique. In this paper, 2D DOSY (1)H NMR offers a new approach for a whole characterization of the various components of these complex mixtures.

10. Photodisintegration of /sup 3/H and /sup 3/He. [Threshold to 25 MeV

SciTech Connect

Faul, D.D.

1980-09-01

The photoneutron cross sections for /sup 3/H and /sup 3/He have been measured from threshold to approx. 25 MeV with monoenergetic photons from the annihilation in flight of fast positrons at the LLL Electron-Positron Linear Accelerator facility. These reactions include the two-body breakup of /sup 3/H and the three-body breakup of both /sup 3/H and /sup 3/He; these measurements for /sup 3/H are the first to span the energy region across the peaks of the cross sections. An efficient BF/sub 3/-tube-and-paraffin neutron detector and high-pressure gaseous samples of several moles each (the activity of the /sup 3/H sample was approx. 200,000 Ci) were employed in these measurements. Measurements on /sup 16/O and /sup 2/H also were performed to verify the absolute cross-section scale. The results, when compared with each other and with results for the two-body breakup cross section for /sup 3/He from the literature, show that the two-body breakup cross sections for /sup 3/H and /sup 3/He have nearly the same shape, but the one for /sup 3/He lies lower in magnitude; the three-body breakup cross section for /sup 3/He lies higher in magnitude and is broader in the peak region and also rises less sharply from threshold than that for /sup 3/H; and these measured differences between the cross sections for the breakup modes largely compensate in their sum, so that the total photon absorption cross sections for /sup 3/H and /sup 3/He are nearly the same in both size and shape at energies near and above their peaks. Theoretical results from the literature disagree with the experimental results to a certain extent over the entire photon-energy region for which the photoneutron cross sections were measured. 50 figures, 7 tables.

11. Synthetic studies towards putative yuremamine using an iterative C(sp(3))-H arylation strategy.

PubMed

Calvert, Matthew B; Sperry, Jonathan

2016-06-28

An overview of an iterative, 8-aminoquinoline (AQ)-directed C(sp(3))-H arylation strategy towards the pyrroloindole structure initially assigned to the alkaloid yuremamine is described. During initial efforts using a model indane system, it was discovered that the iodoresorcinol unit was not a viable C(sp(3))-H arylation partner when masked as its dimethyl ether but upon switching to a MOM group, the ether oxygen served to stabilise the high valent Pd intermediate during the reaction, thus promoting reductive elimination and leading to acceptable yields of the C(sp(3))-H arylation product. The second C(sp(3))-H arylation with an iodopyrogallol gave a 1,3-diarylated model yuremamine system possessing the desired 1,3-cis relationship. When the successful model studies were applied to a pyrroloindole system in pursuit of yuremamine, it became apparent that C9 underwent competing C(sp(2))-H arylation if left vacant, but installing a tryptamine side chain at this site prevented the desired C(sp(3))-H arylation from occurring altogether. However, a C9-methyl pyrroloindole underwent iterative C(sp(3))-H arylation at C1 with an iodoresorcinol followed by C3 with an iodopyrogallol to give a diarylated product with the aryl groups in the undesired 1,3-trans-relationship, arising from epimerisation at C1 during the second C(sp(3))-H arylation event. Although the synthesis of putative yuremamine was not accomplished, several findings are disclosed that will serve as useful additions to the burgeoning field of directed C(sp(3))-H arylations and related C-H functionalization reactions.

12. Enhanced Y1H Assays for Arabidopis

Technology Transfer Automated Retrieval System (TEKTRAN)

Transcription regulation plays a key role in development and response to environment. To understand this mechanism, we need to know which transcription factor (TFs) would bind to which promoter, thus regulate their target gene expression. Yeast one-hybrid (Y1H) technique can be used to map this kind...

13. Synthesis and characterization of 2-phosphonoethanesulfonic acid and a barium-hydrogenphosphonatoethanesulfonate - BaH(O{sub 3}P-C{sub 2}H{sub 4}-SO{sub 3})

SciTech Connect

Sonnauer, Andreas

2008-03-15

Following the strategy of using polyfunctional phosphonic acids for the synthesis of new metal phosphonates, the organic linker molecule 2-phosphonoethanesulfonic acid, H{sub 2}O{sub 3}P-C{sub 2}H{sub 4}-SO{sub 3}H (1) (H{sub 3}L), was synthesized and characterized in detail. The acid was used in a high-throughput (HT) investigation of the system BaCl{sub 2}/H{sub 3}L/NaOH/H{sub 2}O. The HT experiments comprising 48 individual hydrothermal reactions were performed to systematically investigate the influence of pH of the starting mixture as well as the molar ratio Ba{sup 2+}: H{sub 3}L. Only two reaction products were observed: small amounts of BaCO{sub 3} under basic conditions and BaH(O{sub 3}P-C{sub 2}H{sub 4}-SO{sub 3}) (2). For compounds 1 and 2 the crystal structures were determined from single-crystal X-ray diffraction data (H{sub 2}O{sub 3}P-C{sub 2}H{sub 4}-SO{sub 3}H: trigonal, P3{sub 2}, a=814.58(1), c=861.20(2) pm, Z=3, R1=0.0254, wR{sub 2}=0.0758 for I>2{sigma}(I); BaH(O{sub 3}P-C{sub 2}H{sub 4}-SO{sub 3}): orthorhombic, Ibam, a=953.39(19), b=855.55(17), c=867.82(17) pm, Z=4, R1=0.0162, wR{sub 2}=0.0417 for I>2{sigma}(I)). The structure of H{sub 3}L (1) is stabilized exclusively by strong hydrogen bonds. Compound 2 is built up by chains of edge sharing BaO{sub 8} polyhedra. These chains are connected to a three-dimensional network by the -CH{sub 2}CH{sub 2}- linker of the ligand. Thermogravimetric investigation of compound 2, as well as IR spectra of 1 and 2 are presented. - Graphical abstract: The synthesis of the ligand H{sub 2}O{sub 3}P-C{sub 2}H{sub 4}-SO{sub 3}H and its use in the systematic investigation in the system BaCl{sub 2}/H{sub 2}O{sub 3}P-C{sub 2}H{sub 4}-SO{sub 3}H/NaOH/H{sub 2}O led to the new barium phosphonatosulfonate BaH(O{sub 3}P-C{sub 2}H{sub 4}-SO{sub 3}H)

14. A 3D microporous covalent organic framework with exceedingly high C3H8/CH4 and C2 hydrocarbon/CH4 selectivity.

PubMed

Ma, Heping; Ren, Hao; Meng, Shuang; Yan, Zhuojun; Zhao, Huanyu; Sun, Fuxing; Zhu, Guangshan

2013-10-28

Here we present a new 3D microporous COF with a uniform pore size (0.64 nm). MCOF-1 exhibits high adsorption selectivity towards C3H8, C2H6 and C2H4 over CH4 owing to the pore size and preferential adsorption.

15. An iron(III) complex salt containing pyrazole as both ligand and counter-ion: bis(1H-pyrazol-2-ium) pentacyanido(1H-pyrazole-κN(2))ferrate(III).

PubMed

Wang, Yu-Feng; Yu, Chun-Hua; Zhu, Run-Qiang

2014-05-01

The title compound, (C3H5N2)2[Fe(CN)5(C3H4N2)], is composed of a mononuclear [Fe(CN)5(pyrazole)](2-) dianion and two 1H-pyrazol-2-ium cations. A three-dimensional supramolecular network is formed through a rich scheme of N-H...N hydrogen bonds and C-H...π interactions among the cations and anions.

16. THz spectroscopy of D2H+

Yu, S.; Pearson, J. C.; Amano, T.; Matsushima, F.

2017-01-01

We extended the measurements of the rotational transitions of D2H+ up to 3 THz by using the JPL frequency multiplier chains and a TuFIR system at Toyama. D2H+ was generated in an extended negative glow discharge cell cooled to liquid nitrogen temperature. We observed five new THz lines. All the available rotational transition frequencies together with the combination differences derived from the three fundamental bands were subject to least square analysis to determine the molecular constants. New THz measurements are definitely useful for better characterization of spectroscopic properties. The improved molecular constants provide better predictions of other unobserved rotational transitions.

17. Complete (1) H NMR assignment of cedranolides.

PubMed

Perez-Hernandez, Nury; Gordillo-Roman, Barbara; Arrieta-Baez, Daniel; Cerda-Garcia-Rojas, Carlos M; Joseph-Nathan, Pedro

2017-03-01

Complete and unambiguous (1) H NMR chemical shift assignment of α-cedrene (2) and cedrol (9), as well as for α-pipitzol (1), isocedrol (10), and the six related compounds 3-8 has been established by iterative full spin analysis using the PERCH NMR software (PERCH Solutions Ltd., Kuopio, Finland). The total sets of coupling constants are described and correlated with the conformational equilibria of the five-membered ring of 1-10, which were calculated using the complete basis set method. Copyright © 2015 John Wiley & Sons, Ltd.

18. Comparison of (/sup 3/H)nicotine and (/sup 3/H)acetylcholine binding in mouse brain: regional distribution

SciTech Connect

Sershen, H.; Reith, M.E.; Hashim, A.; Lajtha, A.

1985-06-01

In a continuing study of nicotine binding sites, the authors determined the relative amount of nicotine binding and acetylcholine binding in various brain regions of C57/BL and of DBA mice. Although midbrain showed the highest and cerebellum the lowest binding for both (/sup 3/H)nicotine and (/sup 3/H)acetylcholine, the ratio of nicotine to acetylcholine binding showed a three-fold regional variation. Acetylcholine inhibition of (/sup 3/H)nicotine binding indicated that a portion of nicotine binding was not inhibited by acetylcholine. These results indicate important differences between the binding of (+/-)-(/sup 3/H)nicotine and that of (/sup 3/H)acetylcholine.

19. Binding of [3H]-prazosin and [3H]-dihydroergocryptine to rat cardiac alpha-adrenoceptors.

PubMed Central

Guicheney, P.; Meyer, P.

1981-01-01

1 [3H]-prazosin binds specifically to a single class of alpha-adrenoceptors in rat cardiac membranes (KD25 degrees C = 0.2 nM). 2 That these receptors are of the alpha 1-type was indicated by competition studies, i.e. alpha 1-antagonists such as prazosin and (2-(2,6-dimethoxyphenoxyethyl) aminomethyl-1, 4-benzodioxane (WB 4101) were more potent than the alpha 2-antagonists, yohimbine and piperoxan in inhibiting [3H]-prazosin binding. 3 A comparative study of [3H]-prazosin binding and [3H]-dihydroergocryptine binding to cardiac membranes showed that both [3H]-prazosin and [3H]-dihydroergocryptine (at low concentrations) bind to alpha 2-adrenoceptors, while [3H]-dihydroergocryptine (at higher concentrations) also binds to another class of sites. PMID:6269682

20. Anionic ordering and thermal properties of FeF3·3H2O.

PubMed

Burbano, Mario; Duttine, Mathieu; Borkiewicz, Olaf; Wattiaux, Alain; Demourgues, Alain; Salanne, Mathieu; Groult, Henri; Dambournet, Damien

2015-10-05

Iron fluoride trihydrate can be used to prepare iron hydroxyfluoride with the hexagonal-tungsten-bronze (HTB) type structure, a potential cathode material for batteries. To understand this phase transformation, a structural description of β-FeF3·3H2O is first performed by means of DFT calculations and Mössbauer spectroscopy. The structure of this compound consists of infinite chains of [FeF6]n and [FeF2(H2O)4]n. The decomposition of FeF3·3H2O induces a collapse and condensation of these chains, which lead to the stabilization, under specific conditions, of a hydroxyfluoride network FeF3-x(OH)x with the HTB structure. The release of H2O and HF was monitored by thermal analysis and physical characterizations during the decomposition of FeF3·3H2O. An average distribution of FeF4(OH)2 distorted octahedra in HTB-FeF3-x(OH)x was obtained subsequent to the thermal hydrolysis/olation of equatorial anionic positions involving F(-) and H2O. This study provides a clear understanding of the structure and thermal properties of FeF3·3H2O, a material that can potentially bridge the recycling of pickling sludge from the steel industry by preparing battery electrodes.

1. Anionic ordering and thermal properties of FeF3·3H2O

DOE PAGES

Burbano, Mario; Duttine, Mathieu; Borkiewicz, Olaf; ...

2015-09-17

In this study, iron fluoride tri-hydrate can be used to prepare iron hydroxyfluoride with the Hexagonal-Tungsten-Bronze (HTB) type structure, a potential cathode material for batteries. To understand this phase transformation, a structural description of β-FeF3·3H2O is first performed by means of DFT calculations and Mössbauer spectroscopy. The structure of this compound consists of infinite chains of [FeF6]n and [FeF2(H2O)4]n. The decomposition of FeF3·3H2O induces a collapse and condensation of these chains, which lead to the stabilization, under specific conditions, of a hydroxyfluoride network FeF3-x(OH)x with the HTB structure. The release of H2O and HF was monitored by thermal analysis andmore » physical characterizations during the decomposition of FeF3·3H2O. An average distribution of FeF4(OH)2 distorted octahedra in HTB-FeF3-x(OH)x was obtained subsequent to the thermal hydrolysis/olation of equatorial anionic positions involving F- and H2O. This study provides a clear understanding of the structure and thermal properties of FeF3·3H2O, a material that can potentially bridge the recycling of pickling sludge from the steel industry by preparing battery electrodes.« less

2. Expeditious diastereoselective synthesis of elaborated ketones via remote Csp3-H functionalization

2017-01-01

The quest for selective C-H functionalization reactions, able to provide new strategic opportunities for the rapid assembly of molecular complexity, represents a major focus of the chemical community. Examples of non-directed, remote Csp3-H activation to forge complex carbon frameworks remain scarce due to the kinetic stability and thus intrinsic challenge associated to the chemo-, regio- and stereoselective functionalization of aliphatic C-H bonds. Here we describe a radical-mediated, directing-group-free regioselective 1,5-hydrogen transfer of unactivated Csp3-H bonds followed by a second Csp2-H functionalization to produce, with exquisite stereoselectivity, a variety of elaborated fused ketones. This study demonstrates that aliphatic acids can be strategically harnessed as 1,2-diradical synthons and that secondary aliphatic C-H bonds can be engaged in stereoselective C-C bond-forming reactions, highlighting the potential of this protocol for target-oriented natural product and pharmaceutical synthesis.

3. Expeditious diastereoselective synthesis of elaborated ketones via remote Csp(3)-H functionalization.

PubMed

2017-01-13

The quest for selective C-H functionalization reactions, able to provide new strategic opportunities for the rapid assembly of molecular complexity, represents a major focus of the chemical community. Examples of non-directed, remote Csp(3)-H activation to forge complex carbon frameworks remain scarce due to the kinetic stability and thus intrinsic challenge associated to the chemo-, regio- and stereoselective functionalization of aliphatic C-H bonds. Here we describe a radical-mediated, directing-group-free regioselective 1,5-hydrogen transfer of unactivated Csp(3)-H bonds followed by a second Csp(2)-H functionalization to produce, with exquisite stereoselectivity, a variety of elaborated fused ketones. This study demonstrates that aliphatic acids can be strategically harnessed as 1,2-diradical synthons and that secondary aliphatic C-H bonds can be engaged in stereoselective C-C bond-forming reactions, highlighting the potential of this protocol for target-oriented natural product and pharmaceutical synthesis.

4. Effects of delta9-THC on the synaptosomal uptake of 3H-tryptophan and 3H-choline.

PubMed

Johnson, K M; Dewey, W L

1978-01-01

The in vitro addition of (-)-delta9-tetrahydrocannabinol (delta9-THC) resulted in a dose-responsive inhibition of the high-affinity specific synaptosomal uptake of both 3H-tryptophan and 3H-choline in mouse forebrain crude synaptosomal preparations. The approximate concentrations of delta9-THC required to cause a 50% inhibition of the uptake of 3H-tryptophan and 3H-choline were 33 and 16 muM, respectively. Kinetic analysis showed that inhibition of both compounds were consistent with a noncompetitive mechanism. The pretreatment of mice with doses of 10, 30 or 100 mg/kg delta9-THC had no effect on the subsequent in vitro synaptosomal uptake of either 3H-tryptophan or 3H-choline into forebrain synaptosomes.

5. Partial chemical characterization of cyclopyrrolones ((/sup 3/H) suriclone) and benzodiazepines ((/sup 3/H)flunitrazepam) binding site: Differences

SciTech Connect

Zundel, J.L.; Blanchard, J.C.; Julou, L.

1985-06-10

Rat hippocampus membranes were treated with several protein modifying reagents (iodoacetamide, N-ethylmaleimide, tetranitromethane and N-acetylimidazole). The effects of these treatments on the binding sites of cyclopyrrolones ((/sup 3/H) suriclone), a new chemical family of minor tranquilizers, and benzodiazepines ((/sup 3/H) flunitrazepam) were investigated. Here the authors show that both ligands are similarly sensitive to cysteine alkylation: (/sup 3/H) suriclone and (/sup 3/H) flunitrazepam binding are reduced by iodoacetamide and slightly increased by N-ethylmaleimide. On the contrary they are clearly differentiated by tyrosine modification: (/sup 3/H) suriclone binding is not changed whereas (/sup 3/H) flunitrazepam binding is increased by tetranitromethane and decreased by N-acetylimidazole. The present findings and published evidence suggest cyclopyrrolones and benzodiazepines bind to distinct sites or to different allosteric forms of the benzodiazepine receptor. 28 references, 6 figures.

6. Parkinson's disease: decreased density of /sup 3/H-imipramine and /sup 3/H-paroxetine binding sites in putamen

SciTech Connect

Raisman, R.; Cash, R.; Agid, Y.

1986-04-01

The density of high-affinity /sup 3/H-imipramine and /sup 3/H-paroxetine binding sites (two serotonin-uptake blockers) was decreased in the putamen of parkinsonian patients. The correlation between serotonin levels and the number of /sup 3/H-imipramine and /sup 3/H-paroxetine binding sites suggests that they are located on serotoninergic nerve terminals and could be used to study serotoninergic innervation in the human brain. Since imipramine and paroxetine are powerful antidepressants, these results furthermore suggest that decreased serotoninergic transmission may be implicated in the pathophysiology of depression in Parkinson's disease.

7. Comparison of ( sup 3 H)Phencyclidine (( sup 3 H)PCP) and ( sup 3 H) N-(1-(2-thienyl) cyclohexyl)piperidine (( sup 3 H)TCP) binding properties to rat and human brain membranes

SciTech Connect

Vignon, J.; Chaudieu, I.; Allaoua, H.; Journod, L.; Javoy-Agid, F.; Agid, Y.; Chicheportiche, R.

1989-01-01

The investigation of ({sup 3}H)PCP and ({sup 3}H)TCP binding properties to rat cerebrum and cerebellum resulted in the demonstration of multiple binding sites for the two drugs. In the two tissue preparations PCP had a lower affinity than TCP. In membranes from the cerebrum an equal number of high affinity binding sites were present for ({sup 3}H)PCP and ({sup 3}H)TCP. However, low affinity binding sites were two times more numerous for ({sup 3}H)PCP than for ({sup 3}H)TCP. In the cerebellum, the number of high and low affinity sites labeled by the two radioligands was identical, but the number of high affinity sites was about 7 fold lower than in cerebrum. In human cerebral cortex samples ({sup 3}H)TCP also bound to two different sites. The number of high and low affinity sites were 12 and 3 times, respectively, less abundant than in the rat cerebrum. Low affinity sites were of higher affinity than corresponding sites in the rat brain. In the human cerebellum ({sup 3}H)TCP binding parameters were identical to those measured in the same region in the rat.

8. Synthesis Of [2h, 13c] And [2h3, 13c]Methyl Aryl Sulfides

DOEpatents

Martinez, Rodolfo A.; Alvarez, Marc A.; Silks, III, Louis A.; Unkefer, Clifford J.

2004-03-30

The present invention is directed to labeled compounds, [.sup.2 H.sub.1, .sup.13 C], [.sup.2 H.sub.2, .sup.13 C] and [.sup.2 H.sub.3, .sup.13 C]methyl aryl sulfides wherein the .sup.13 C methyl group attached to the sulfur of the sulfide includes exactly one, two or three deuterium atoms and the aryl group is selected from the group consisting of 1-naphthyl, substituted 1-naphthyl, 2-naphthyl, substituted 2-naphthyl, and phenyl groups with the structure ##STR1## wherein R.sub.1, R.sub.2, R.sub.3, R.sub.4, and R.sub.5 are each independently, hydrogen, a C.sub.1 -C.sub.4 lower alkyl, a halogen, an amino group from the group consisting of NH.sub.2, NHR and NRR' where R and R' are each a C.sub.1 -C.sub.4 lower alkyl, a phenyl, or an alkoxy group. The present invention is also directed to processes of preparing [.sup.2 H.sub.1, .sup.13 C], [.sup.2 H.sub.2,.sup.13 C] and [.sup.2 H.sub.3, .sup.13 C]methyl aryl sulfides wherein the .sup.13 C methyl group attached to the sulfur of the sulfide includes exactly one, two or three deuterium atoms. The present invention is also directed to the labeled compounds of [.sup.2 H.sub.1, .sup.13 C]methyl iodide and [.sup.2 H.sub.2, .sup.13 C]methyl iodide.

9. Binding of [3H]idazoxan and of its methoxy derivative [3H] RX821002 in human fat cells: [3H]idazoxan but not [3H] RX821002 labels additional non-alpha 2-adrenergic binding sites.

PubMed

Langin, D; Paris, H; Lafontan, M

1990-06-01

10. /sup 3/H-imipramine uptake into rat striatal slices and imipramine-induced /sup 3/H-dopamine efflux

SciTech Connect

Saito, R.; Kawasaki, K.; Ono, N.; Kamiya, H.

1983-04-01

The effect of imipramine on spontaneous efflux of radiolabelled dopamine (DA) from slices of rat striatum was examined by a superfusion method. Imipramine at concentrations of 10 - 100 microM enhanced the efflux of DA accumulated in a high-affinity uptake system in a concentration-dependent manner. This efflux of /sup 3/H-DA was not affected by conditions (Ca/sup 2 +/-free medium, 100 microM bretylium and 30 microM tetrodotoxin) which inhibited the release of /sup 3/H-DA by electrical stimulation. Furthermore, this imipramine-induced /sup 3/H-DA efflux was temperature-dependent. The uptake of /sup 3/H-imipramine into striatal slices was determined. This uptake was concentration- and temperature-dependent and increased linearly. These results are discussed in relation to the hypothesis that /sup 3/H-DA efflux by imipramine is connected with uptake of imipramine.

11. Assimilation of 3H in photosynthesizing leaves exposed to HTO.

PubMed

Guenot, J; Belot, Y

1984-12-01

Potato and wine grape plants were exposed for a period of 4 h to tritiated water vapor, and simultaneously to 14CO2 which served as a tracer for photosynthetic assimilation. During and after exposure, foliar samples were collected in which the exchangeable and nonexchangeable fractions of organic 3H were determined, taking care that the exchangeable fraction should not be lost to atmosphere. It was demonstrated that about 20% of the organic H in vegetation could be exchanged with 3H of tissue water, and that nonexchangeable 3H was fixed by photosynthesis. The kinetic behavior of the 2 forms was very different.

12. Crystalline 1H-1,2,3-triazol-5-ylidenes

SciTech Connect

2016-08-02

The present invention provides novel and stable crystalline 1H-1,2,3 triazolium carbenes and metal complexes of 1H-1,2,3 triazolium carbenes. The present invention also provides methods of making 1H-1,2,3 triazolium carbenes and metal complexes of 1H-1,2,3 triazolium carbenes. The present invention also provides methods of using 1H-1,2,3 triazolium carbenes and metal complexes of 1H-1,2,3 triazolium carbenes in catalytic reactions.

13. Renal Aldosterone Receptors: Studies with [3H]Aldosterone and the Anti-Mineralocorticoid [3H]Spirolactone (SC-26304)

PubMed Central

Marver, Diana; Stewart, John; Funder, John W.; Feldman, David; Edelman, Isidore S.

1974-01-01

In vivo, a spirolactone (SC-26304) inhibited the effects of aldosterone on urinary K+:Na+ ratios and the binding of [3H]aldosterone to renal cytoplasmic and nuclear receptors. Cytoplasmic binding of [3H]aldosterone and [3H]spirolactone (SC-26304) was similar in magnitude and involved the same set of sites. Under three sets of conditions—(i) in the intact rat, (ii) in kidney slices, and (iii) in reconstitution studies (mixing prelabeled cytoplasm with either purified renal nuclei or chromatin), [3H]spirolactone (SC-26304) did not yield specific nuclear complexes in contrast to the reproducible generation of these complexes with [3H]aldosterone. In glycerol density gradients, cytoplasmic [3H]aldosterone receptor complexes sedimented at 8.5 S and 4 S in low concentrations of salt and at 4.5 S in high concentrations of salt. Cytoplasmic [3H]spirolactone (SC-26304) receptor complexes sedimented at 3 S in low concentrations of salt and 4 S in high concentrations of salt. These results are discussed in terms of an allosteric model of the receptor system. Images PMID:4364539

14. (/sup 3/H) clonidine binding to rat hippocampal membranes

SciTech Connect

George, C.R.

1982-02-01

Alpha adrenergic receptor subtypes in rat hippocampal membranes were studied, using (/sup 3/H) clonidine as the radioactive ligand. On the basis of competitive binding studies, using the selective antagonist-prazosin, WB-4101, and yohimbine, (/sup 3/H) clonidine appeared to bind to a population of presynaptic sites that are pharmacologically similar to receptors previously classified as alpha 2. A computerized model that linearized and produced the best possible fit to the experimental data points indicated that (/sup 3/H) clonidine binds to a single population of receptors possessing equal affinity for the ligand. Binding data also indicated that rat hippo-campus contains significantly fewer (/sup 3/H)clonidine binding sites than rat cortex.

15. (/sup 3/H)-beta-endorphin binding in rat brain

SciTech Connect

Houghten, R.A.; Johnson, N.; Pasternak, G.W.

1984-10-01

The binding of (/sup 3/H)-beta-endorphin to rat brain homogenates is complex. Although Scatchard analysis of saturation studies yields a straight line, detailed competition studies are multiphasic, suggesting that even at low concentrations of the compound, the /sup 3/H-ligand is binding to more than one class of site. A portion of (/sup 3/H)-beta-endorphin binding is sensitive to low concentrations of morphine or D-Ala2-Leu5-enkephalin (less than 5 nM). The inhibition observed with each compound alone (5 nM) is the same as that seen with both together (each at 5 nM). Thus, the binding remaining in the presence of both morphine and the enkephalin does not correspond to either mu or delta sites. The portion of (/sup 3/H)-beta-endorphin binding that is inhibited under these conditions appears to be equally sensitive to both morphine and the enkephalin and may correspond to mu1 sites. Treating membrane homogenates with naloxonazine, a mu1 selective antagonist, lowers (/sup 3/H)-beta-endorphin binding to the same degree as morphine and D-Ala2-Leu5-enkephalin alone or together. This possible binding of (/sup 3/H)-beta-endorphin to mu1 sites is consistent with the role of mu1 sites in beta-endorphin analgesia and catalepsy in vivo.

16. Photochemical Modeling of the Distribution of C3H8 in the Atmosphere of Saturn

Edgington, S. G.; Simon-Miller, A.; Jennings, D.; Bjoraker, G.; Romani, P.; Achterberg, R.; Orton, G.; Flasar, M.; Cassini CIRS Team

2005-08-01

Cassini's Composite Infrared Spectrometer (CIRS) has measured the abundance of C2H2 and C3H8 (Propane) at several latitudes in the Southern hemisphere. An increase of radiance with latitude towards the pole has been observed, possibly implying a corresponding increase of C3H8. In an effort explain the observed distribution of both species, it is important to model the creation, destruction, and transport of these chemical species. Furthermore, since both molecules have overlapping absorption features in the same spectral region near 748 cm-1, such modeling will aid in refining derived abundances and separating temperature effects. The photochemistry model used in Edgington et al. (1998, 1999, 2000) to model simultaneously hydrocarbons, ammonia, and phosphine is updated and expanded to include paths relevant to the creation of C3H8. Destruction occurs through photolysis, while transport would tend to spread C3H8 from its source regions. With a series of exercises in 1- and 2- dimensions, we explore the extent to which photolysis, vertical, and/or meridional transport impacts the distribution of C2H2 and C3H8 with latitude. Thermal profiles derived from CIRS observations versus latitude are used as they have an impact on numerous reaction rates. We then compare these results with abundances derived from observations taken with the CIRS instrument. Edgington, S.G., West, R.A., Friedson, A.J., Atreya, S.K., 2000. A 2-D photochemical model with meridional circulation. Bull. American. Astron. Soc., 32, 1013. Edgington, S.G., S.K. Atreya, L.M. Trafton, J.J. Caldwell, R.F. Beebe, A.A. Simon, and R.A. West, 1999. Ammonia and eddy mixing variations in the southern hemisphere of Jupiter from HST Faint Object Spectrograph Observations. Icarus, 142, 342-357. Edgington, S.G., S.K. Atreya, L.M. Trafton, J.J. Caldwell, R.F. Beebe, A.A. Simon, R.A. West, and C. Barnet, 1998. On the latitude variation of ammonia, acetylene, and phosphine altitude profiles on Jupiter from HST Faint

17. The structure and properties of 5,6-dinitro-1H-benzotriazole

Santa María, Dolores; Claramunt, Rosa M.; Torralba, M. Carmen; Torres, M. Rosario; Alkorta, Ibon; Elguero, José

2016-06-01

5,6-Dinitro-1H-benzotriazole crystallizes in the monoclinic system, space group P21/c. The asymmetric unit contains the planar 1H-tautomer together with a water molecule of crystallization. Each water molecule is hydrogen bonded to three adjacent 5,6-dinitrobenzotriazoles forming a tape along the b-axis of the crystal. These tapes stack along the c-axis through hydrogen bonds involving the water molecules and one of the nitro groups leading to a bidimensional structure. Solid-state 13C and 15N CPMAS NMR allow to confirm that the tautomer present is the 1H one. In DMSO-d6 solution the results are quite different and, based on GIAO/B3LYP/6-311++G(d,p) calculations, lead us to conclude that the major tautomer is the 5,6-dinitro-2H-benzotriazole, a surprising result that contradicts the rule that the major tautomer in solution coincides with the one present in the crystal. An anhydrous pseudopolymorph of 5,6-dinitro-1H-benzotriazole has been obtained as a non-crystalline form and from solid-state NMR and theoretical calculations, we conclude that it is an 1H-tautomer.

18. 40 CFR 721.5540 - 1H,3H,5H-oxazolo [3,4-c] oxazole, dihydro-7a-methyl-.

Code of Federal Regulations, 2010 CFR

2010-07-01

...) Protection in the workplace. Requirements as specified in § 721.63 (a)(2)(iii) and (a)(3). (ii) Release to water. Requirements as specified in § 721.90 (a)(4), (b)(4), and (c)(4) (where N = 500 ppb). (b) Specific requirements. The provisions of subpart A of this part apply to this section except as modified...

19. Crystal structure of (3E)-5-nitro-3-(2-phenyl­hydrazinyl­idene)-1H-indol-2(3H)-one

PubMed Central

Velasques, Jecika Maciel; Gervini, Vanessa Carratu; Bortoluzzi, Adaílton João; de Farias, Renan Lira; de Oliveira, Adriano Bof

2017-01-01

The reaction between 5-nitro­isatin and phenyl­hydrazine in acidic ethanol yields the title compound, C14H10N4O3, whose mol­ecular structure deviates slightly from a planar geometry (r.m.s. deviation = 0.065 Å for the mean plane through all non-H atoms). An intra­molecular N—H⋯O hydrogen bond is present, forming a ring of graph-set motif S(6). In the crystal, mol­ecules are linked by N—H⋯O and C—H⋯O hydrogen-bonding inter­actions into a two-dimensional network along (120), and rings of graph-set motif R 2 2(8), R 2 2(26) and R 4 4(32) are observed. Additionally, a Hirshfeld surface analysis suggests that the mol­ecules are stacked along [100] through C=O⋯Cg inter­actions and indicates that the most important contributions for the crystal structure are O⋯H (28.5%) and H⋯H (26.7%) inter­actions. An in silico evaluation of the title compound with the DHFR enzyme (di­hydro­folate reductase) was performed. The isatin–hydrazone derivative and the active site of the selected enzyme show N—H⋯O(ASP29), N—H⋯O(ILE96) and Cg⋯Cg(PHE33) inter­actions. PMID:28217335

20. Crystal structure of (3E)-5-nitro-3-(2-phenyl-hydrazinyl-idene)-1H-indol-2(3H)-one.

PubMed

Velasques, Jecika Maciel; Gervini, Vanessa Carratu; Bortoluzzi, Adaílton João; de Farias, Renan Lira; de Oliveira, Adriano Bof

2017-02-01

The reaction between 5-nitro-isatin and phenyl-hydrazine in acidic ethanol yields the title compound, C14H10N4O3, whose mol-ecular structure deviates slightly from a planar geometry (r.m.s. deviation = 0.065 Å for the mean plane through all non-H atoms). An intra-molecular N-H⋯O hydrogen bond is present, forming a ring of graph-set motif S(6). In the crystal, mol-ecules are linked by N-H⋯O and C-H⋯O hydrogen-bonding inter-actions into a two-dimensional network along (120), and rings of graph-set motif R2(2)(8), R2(2)(26) and R4(4)(32) are observed. Additionally, a Hirshfeld surface analysis suggests that the mol-ecules are stacked along [100] through C=O⋯Cg inter-actions and indicates that the most important contributions for the crystal structure are O⋯H (28.5%) and H⋯H (26.7%) inter-actions. An in silico evaluation of the title compound with the DHFR enzyme (di-hydro-folate reductase) was performed. The isatin-hydrazone derivative and the active site of the selected enzyme show N-H⋯O(ASP29), N-H⋯O(ILE96) and Cg⋯Cg(PHE33) inter-actions.

1. 1,3-Dibenzyl-6-bromo-1H-imidazo[4,5-b]pyridin-2(3H)-one

PubMed Central

Dahmani, S.; Kandri Rodi, Y.; Capet, F.; Essassi, El Mokhtar; Ng, Seik Weng

2010-01-01

The imidazopyridine fused-ring in the title compound, C20H16BrN3O, is planar (r.m.s. deviation = 0.011 Å). The phenyl rings of the benzyl substitutents twist away from the central five-membered ring in opposite directions; the rings are aligned at 61.3 (1) and 71.2 (1)° with respect to this ring. PMID:21580599

2. 1,3-Bis(prop-2-yn-1-yl)-1H-anthra[1,2-d]imidazole-2,6,11(3H)-trione

PubMed Central

Afrakssou, Zahra; Haoudi, Amal; Capet, Frédéric; Mazzah, Ahmed; Rolando, Christian; El Ammari, Lahcen

2013-01-01

In the title compound, C21H12N2O3, the fused-ring system is roughly planar, the largest deviation from the mean plane being 0.084 (2) Å. The two prop-2-yn-1-yl groups are almost perpendicular to the fused ring plane, making C—C—N—C torsion angles of −103.4 (2) and −105.3 (2)°, and point in opposite directions with respect to the plane. In the crystal, mol­ecules are linked by weak C—H⋯O hydrogen bonds, forming a three-dimensional network. PMID:23795107

3. 1,3-Dibenzyl-1H-anthra[1,2-d]imidazole-2,6,11(3H)-trione

PubMed Central

Afrakssou, Zahra; Kandri Rodi, Youssef; Capet, Frédéric; Essassi, El Mokhtar; El Ammari, Lahcen

2011-01-01

The mol­ecule of the title compound, C29H20N2O3, contains four fused rings, three are six-membered rings and one is the five-membered imidazole ring. The fused-ring system is linked to two benzyl groups. The four fused rings are folded around the O=C⋯C=O direction of the anthraquinone, with a dihedral angle of 16.36 (8)° between the two terminal rings (A and D). The imidazole ring (D) is almost perpendicular to the two benzyl groups (E and F) with dihedral angles of 86.69 (17) and 83.15 (13)°, respectively. In the crystal, adjacent mol­ecules are linked by inter­molecular C—H⋯O hydrogen bonding. PMID:21754544

4. 6-Bromo-1,3-di-2-propynyl-1H-imidazo[4,5-b]pyridin-2(3H)-one

PubMed Central

Dahmani, S.; Haoudi, A.; Capet, F.; Essassi, El Mokhtar; Ng, Seik Weng

2010-01-01

The room-temperature reaction of propargyl bromide and 6-bromo-1,3-dihydro­imidazo[4,5-b]pyridin-2-one in dimethyl­formamide yields the title compound, C12H8BrN3O, which features nitro­gen-bound propynyl substituents. The imidazopyridine fused ring is almost planar (r.m.s. deviation = 0.011 Å); the propynyl chains point in opposite directions relative to the fused ring. One acetyl­enic H atom is hydrogen bonded to the carbonyl O atom of an inversion-related mol­ecule, forming a dimer; adjacent dimers are linked by a second acetyl­ene–pyridine C—H⋯N inter­action, forming a layer motif. PMID:21580601

5. Synthesis and evaluation of LOX inhibitory activity of 2-(1,3-Dioxo-1H-benzo[de]isoquinolin-2(3H)-yl)-N-phenylacetamide derivatives

PubMed Central

2016-01-01

A family of structurally related LOX enzymes present in human cells which catalyse the metabolism of released arachidonic acid from phospholipids by inflammatory stimuli, to biologically active mediators. Mainly, expression of three types of LOXs occurs in cells, which catalyse the insertion of molecular oxygen into the molecule of arachidonic acid at carbon 5, 12, and 15. According to this chemical reaction, the LOXs are named 5-, 12-, and 15-LOX, amongst which, 15-LOX with isoforms 15-LOX-1 and 15-LOX-2 have critical role in neoplastic diseases. 15-LOX-1 is overexpressed in some neoplastic conditions. Hence, in this research, we focused on the synthesis of naphthalimide analogs as potential 15-LOX-1 inhibitors. Fortunately, the most of synthesized compounds demonstrated remarkable inhibitory potency towards 15-LOX-1 in nanomolar ranges. Naphthalimide derivatives could be suggested as potential LOX inhibitors with likely applications of anticancer activity. PMID:27651806

6. Crystal structure of 1,5-diethyl-1H-1,5-benzodiazepine-2,4(3H,5H)-di­thione

PubMed Central

Lamkaddem, Abderrahman; Harcharras, Mohamed; Shaim, Abdelillah; Zouihri, Hafid; Echchahed, Bousselham; Bi, Wenhua

2015-01-01

In the title compound, C13H16N2S2, the seven-membered ring adopts a boat conformation, with the two phenyl­ene C atoms representing the stern and the methyl­ene C atom as the prow. The thione S atoms and N-bound ethyl groups lie on the opposite side of the mol­ecule to the phenyl­ene ring so that the mol­ecule approximates mirror symmetry. In the crystal, supra­molecular layers in the bc plane are sustained by a pair of C—H⋯S inter­actions to the same S atom acceptor. PMID:25878883

7. Pelanserin: 3-[3-(4-phenyl­piperazin-1-yl)prop­yl]quinazoline-2,4(1H,3H)-dione

PubMed Central

Aguirre Hernández, Gerardo; Somanathan, Ratnasamy; Bernès, Sylvain

2014-01-01

The title compound, C21H24N4O2, is a potent serotonin 5-HT2 and α1-adrenoceptor antagonist. The n-propyl chain links the quinazolinedione heterocycle and the phenyl­piperazine group in which the benzene ring is equatorially located and the piperazine ring has the expected chair conformation. The dihedral angle between the planes of the benzene ring and the quinazolinedione ring system is 74.1 (1)°. In the crystal, mol­ecules form centrosymmetric dimers through R 2 2(8) hydrogen-bonded rings involving the amine and one carbonyl group of the quinazolinedione moiety. These dimers are extended into chains extending along the a-axis direction through expanded centrosymmetric cyclic C—H⋯O associations involving the second carbonyl group, giving R 2 2(20) and R 1 2(7) motifs. PMID:25249922

8. 3-Ethyl-3-hy-droxy-8-meth-oxy-quinoline-2,4(1H,3H)-dione monohydrate.

PubMed

Kafka, Stanislav; Pevec, Andrej; Proisl, Karel; Kimmel, Roman; Košmrlj, Janez

2012-11-01

In the title hydrate, C(12)H(13)NO(4)·H(2)O, the piperidine ring that is fused to the benzene ring is in a sofa conformation with the chiral C atom lying 0.4084 (18) Å out of the plane of the nine fused-ring atoms. In the crystal, O-H⋯O and N-H⋯O hydrogen bonds link the organic mol-ecules and water mol-ecules into chains running along the b-axis direction. The chains are further connected into layers parallel to the bc plane by π-π inter-actions between inversion-related benzene rings [centroid-centroid distance = 3.8846 (9) Å].

9. Photoaffinity labeling of human platelet and rabbit kidney. cap alpha. -adrenoceptors with (/sup 3/H)SKF 102229

SciTech Connect

Regan, J.W.; Raymond, J.R.; Lefkowitz, R.J.; DeMarinis, R.M.

1986-06-13

A newly developed ..cap alpha../sub 2/-adrenergic photoaffinity ligand, 3-methyl-6-chloro-9-azido-1H-2,3,4,5-tetrahydro-3-benzazepine (SKF 102229), has been radiolabeled with tritium to a specific activity of approx. 80 Ci/mmol. Using membranes prepared from human platelets and from rabbit kidney, ..cap alpha../sub 2/-adrenoceptors have been covalently labeled following photolysis in the presence of (/sup 3/H)SKF 102229. As determined by SDS-PAGE, the apparent molecular weight of ..cap alpha../sub 2/-adrenoceptors from both of these tissues was 64,000. The yield of covalent insertion of (/sup 3/H)SKF 102229 into the ..cap alpha../sub 2/-adrenoceptor was very good. Thus, following photolysis up to 90% of the ..cap alpha../sub 2/-adrenoceptors could be irreversibly labeled with (/sup 3/H)SKF 102229.

10. Stimulation of [3H] GABA and beta-[3H] alanine release from rat brain slices by cis-4-aminocrotonic acid.

PubMed

Chebib, M; Johnston, G A

1997-02-01

cis-4-Aminocrotonic acid (CACA; 100 microM), an analogue of GABA in a folded conformation, stimulated the passive release of [3H] GABA from slices of rat cerebellum, cerebral cortex, retina, and spinal cord and of beta-[3H]alanine from slices of cerebellum and spinal cord without influencing potassium-evoked release. In contrast, CACA (100 microM) did not stimulate the passive release of [3H]taurine from slices of cerebellum and spinal cord or of D-[3H]aspartate from slices of cerebellum and did not influence potassium-evoked release of [3H]-taurine from the cerebellum and spinal cord and D-[3H]-aspartate from the cerebellum. These results suggest that the effects of CACA on GABA and beta-alanine release are due to CACA acting as a substrate for a beta-alanine-sensitive GABA transport system, consistent with CACA inhibiting the uptake of beta-[3H]alanine into slices of rat cerebellum and cerebral cortex. The observed Ki for CACA against beta-[3H]alanine uptake in the cerebellum was 750 +/- 60 microM. CACA appears to be 10-fold weaker as a substrate for the transporter system than as an agonist for the GABAc receptor. The effects of CACA on GABA and beta-alanine release provide indirect evidence for a GABA transporter in cerebellum, cerebral cortex, retina, and spinal cord that transports GABA, beta-alanine, CACA, and nipecotic acid that has a similar pharmacological profile to that of the GABA transporter, GAT-3, cloned from rat CNS. The structural similarities of GABA, beta-alanine, CACA, and nipecotic acid are demonstrated by computer-aided molecular modeling, providing information on the possible conformations of these substances being transported by a common carrier protein.

11. Uptake of /sup 3/H-choline and synthesis of /sup 3/H-acetylcholine by human penile corpus cavernosum

SciTech Connect

Blanco, R.; Saenz de Tejada, I.; Azadzoi, K.; Goldstein, I.; Krane, R.J.; Wotiz, H.H.; Cohen, R.A.

1986-03-05

The neuroeffectors which relax penile smooth muscle and lead to erection are unknown; physiological studies of human corpus cavernosum, in vitro, have suggested a significant role of cholinergic neurotransmission. To further characterize the importance of cholinergic nerves, biopsies of human corpus cavernosum were obtained at the time of penile prosthesis implantation. Tissues were incubated in /sup 3/H-choline (10/sup -5/M, 80 Ci/mmol) in oxygenated physiological salt solution at 37/sup 0/C, pH 7.4 for 1 hour. Radiolabelled compounds were extracted with perchloric acid (0.4 M) and acetylcholine and choline were separated by HPLC; /sup 14/C-acetylcholine was used as internal standard. /sup 3/H-choline was accumulated by the tissues (20 +/- 1.9 fmol/mg), and /sup 3/H-acetylcholine was synthesized (4.0 +/- 1.1 fmol/mg). In control experiments, heating of the tissue blocked synthesis of /sup 3/H-acetylcholine. Inhibition of high affinity choline transport by hemicholinium-3 (10/sup -5/M) diminished tissue accumulation of /sup 3/H-choline and significantly reduced the synthesis of /sup 3/H-acetylcholine (0.5 +/ 0.2 fmol/mg, p < 0.05). These results provide direct evidence of neuronal accumulation of choline and enzymatic conversion to acetylcholine in human corpus cavernosum. Taken together with the physiological studies, it can be concluded that cholinergic neurotransmission in human corpus cavernosum plays a role in penile erection.

12. Modulation of [3H]MK-801 binding to NMDA receptors in vivo and in vitro.

PubMed

Murray, F; Kennedy, J; Hutson, P H; Elliot, J; Huscroft, I; Mohnen, K; Russell, M G; Grimwood, S

2000-06-02

[3H]MK-801 binding in vivo was used to determine the occupancy of NMDA receptor ligands shown to allosterically modulate binding in vitro. ED(50) values (mg/kg) were obtained for the channel blockers (+)-5-methyl-10,11-dihydro-5,4-dibenzo[a,d]cyclohepten-5,10-imine maleate ((+)-MK-801, 0.2), 1-(1-phenylcyclohexyl)piperidine (phencyclidine, PCP, 1.7) and ketamine (4.4). Antagonists at the glutamate (DL-(2-carboxypiperazine-4-yl)propyl-1-phosphonate (DL-CPP, 5.7)) and glycine site (7-Chloro-4-hydroxy-3-(3-phenoxy)-phenyl-2(H)quinolinone (L-701,324, 14.1), 3R(+)cis-4-methyl-pyrrollid-2-one (L-687,414, 15.1)) inhibited [3H]MK-801 binding in vivo to varying maximum levels (69%, 103% and 45%, respectively). NR2B subunit-selective compounds acting at the ifenprodil site inhibited [3H]MK-801 in vivo by a maximum of 52-72% and gave ED(50) values (mg/kg) of: (+/-)-(1S*, 2S*)-1-(4-hydroxyphenyl)-2-(4-hydroxy-4-phenylpiperidino)-1-propanol ((+/-)CP-101,606), 1.9; (+/-)-(3R, 4S)-3-[4-(4-fluorophenyl)-4-hydroxypiperidin-1-yl]chroman-4,7-diol ((+/-)CP-283,097), 1.8; (+/-)-(R*, S*)-alpha-(4-hydroxyphenyl)-beta-methyl-4-(phenylmethyl)-1-piperidine propanol ((+/-)Ro 25-6981), 1.0; ifenprodil, 6.0. The glycine site agonist D-serine stimulated binding to 151% of control with an ED(50) of 1.7 mg/kg. Results show that [3H]MK-801 binding in vivo may be used to measure receptor occupancy of ligands acting not only within the ion channel but also at modulatory sites on the NMDA receptor complex.

13. Detection of Apoptosis and Necrosis in Normal Human Lung Cells Using 1H NMR Spectroscopy

Shih, Chwen-Ming; Ko, Wun-Chang; Yang, Liang-Yo; Lin, Chien-Ju; Wu, Jui-Sheng; Lo, Tsui-Yun; Wang, Shwu-Huey; Chen, Chien-Tsu

2005-05-01

This study aimed to detect apoptosis and necrosis in MRC-5, a normal human lung cell line, by using noninvasive proton nuclear magnetic resonance (1H NMR). Live MRC-5 cells were processed first for 1H NMR spectroscopy; subsequently their types and the percentage of cell death were assessed on a flow cytometer. Cadmium (Cd) and mercury (Hg) induced apoptosis and necrosis in MRC-5 cells, respectively, as revealed by phosphatidylserine externalization on a flow cytometer. The spectral intensity ratio of methylene (CH2) resonance (at 1.3 ppm) to methyl (CH3) resonance (at 0.9 ppm) was directly proportional to the percentage of apoptosis and strongly and positively correlated with PI staining after Cd treatment (r2 = 0.9868, P < 0.01). In contrast, this ratio only increased slightly within 2-h Hg treatment, and longer Hg exposure failed to produce further increase. Following 2-h Hg exposure, the spectral intensity of choline resonance (at 3.2 ppm) was abolished, but this phenomenon was absent in Cd-induced apoptosis. These findings together demonstrate that 1H NMR is a novel tool with a quantitative potential to distinguish apoptosis from necrosis as early as the onset of cell death in normal human lung cells.

14. Rabbit blastocysts accumulate [3H]prostaglandins in vitro.

PubMed

Jones, M A; Harper, M J

1984-08-01

Rabbit blastocysts obtained on days 5, 6, and 6.8 of pregnancy were incubated in vitro in Tyrode's buffer with 3H-labeled prostaglandins (PGs). Accumulation of PGs was studied, using Whatman GF/F filters to separate bound and free ligands. The uptake and efflux of [3H]PGs were studied as a function of PG type, incubation time, temperature, and effect of metabolic inhibitors as well as age and number of blastocysts. Blastocysts of the same age accumulated approximately the same amount of [3H]PGE2 and [3H]PGF2 alpha from their environment; however, there was no apparent saturation over a PG concentration range of 1-1000 nM. Both the uptake and efflux of PG were age dependent, with older blastocysts accumulating more PGs. Approximately 90% of the [3H]PGs appear to be transported into the blastocoelic fluid, with little PG remaining in the blastomeres. PG accumulation was relatively insensitive to azide, ouabain, cyanide, or bromcresol green, but was affected by incubation at 0 C or the addition of indomethacin (10 micrograms/ml). No catabolism of the accumulated PGs was observed. The release of PGE2 in general did not differ from that of PGF2 alpha, except on day 6.8 of pregnancy when PGE2 was released more rapidly than on day 6. We conclude that rabbit blastocysts can accumulate PGs from their environment, which may imply a storage potential in the blastocyst and release before implantation.

15. Calculational and Experimental Investigations of the Pressure Effects on Radical - Radical Cross Combinations Reactions: C2H5 + C2H3

NASA Technical Reports Server (NTRS)

Fahr, Askar; Halpern, Joshua B.; Tardy, Dwight C.

2007-01-01

Pressure-dependent product yields have been experimentally determined for the cross-radical reaction C2H5 + C2H3. These results have been extended by calculations. It is shown that the chemically activated combination adduct, 1-C4H8*, is either stabilized by bimolecular collisions or subject to a variety of unimolecular reactions including cyclizations and decompositions. Therefore the "apparent" combination/disproportionation ratio exhibits a complex pressure dependence. The experimental studies were performed at 298 K and at selected pressures between about 4 Torr (0.5 kPa) and 760 Torr (101 kPa). Ethyl and vinyl radicals were simultaneously produced by 193 nm excimer laser photolysis of C2H5COC2H3 or photolysis of C2H3Br and C2H5COC2H5. Gas chromatograph/mass spectrometry/flame ionization detection (GC/MS/FID) were used to identify and quantify the final reaction products. The major combination reactions at pressures between 500 (66.5 kPa) and 760 Torr are (1c) C2H5 + C2H3 yields 1-butene, (2c) C2H5 + C2H5 yields n-butane, and (3c) C2H3 + C2H3 yields 1,3-butadiene. The major products of the disproportionation reactions are ethane, ethylene, and acetylene. At moderate and lower pressures, secondary products, including propene, propane, isobutene, 2-butene (cis and trans), 1-pentene, 1,4-pentadiene, and 1,5-hexadiene are also observed. Two isomers of C4H6, cyclobutene and/or 1,2-butadiene, were also among the likely products. The pressure-dependent yield of the cross-combination product, 1-butene, was compared to the yield of n-butane, the combination product of reaction (2c), which was found to be independent of pressure over the range of this study. The [ 1-C4H8]/[C4H10] ratio was reduced from approx.1.2 at 760 Torr (101 kPa) to approx.0.5 at 100 Torr (13.3 kPa) and approx.0.1 at pressures lower than about 5 Torr (approx.0.7 kPa). Electronic structure and RRKM calculations were used to simulate both unimolecular and bimolecular processes. The relative importance

16. Homocatenation of aluminum: alkane-like structures of Li2Al2 H6 and Li3Al3H8.

PubMed

Gish, J Tyler; Popov, Ivan A; Boldyrev, Alexander I

2015-03-27

Invited for the cover of this issue is Alexander I. Boldyrev and co-workers at Utah State University. The image depicts the magician who symbolizes a chemist synthesizing molecules of "aluminum homocatenated ethane and propane" based on the idea of electronic transmutation. Read the full text of the article at 10.1002/chem.201500298.

17. Evaporation and concentration gradients created by episodic river recharge in a semi-arid zone aquifer: Insights from Cl-, δ18O, δ2H, and 3H

Meredith, K. T.; Hollins, S. E.; Hughes, C. E.; Cendón, D. I.; Chisari, R.; Griffiths, A.; Crawford, J.

2015-10-01

This study has significantly advanced our understanding of the origin of groundwater recharge in a semi-arid zone region of the Darling River catchment, Australia. The generally accepted hypothesis in arid zone environments in Australia that river water forms the primary groundwater recharge source has proven difficult to monitor. This is due to the time lags between large floods, the remoteness and expense of studying these hydrologically complex systems in detail. In addition, the highly episodic nature of dryland rivers complicates the interpretation of the groundwater signal. A range of hydrochemical tracers (chloride, oxygen-18, deuterium and tritium) measured in rain, river water, soil water and groundwater were used in this multi-year study to trace the pathways of groundwater recharge under wet and dry climatic conditions. The evaporation and Cl concentrations observed in the unsaturated zone confirmed that small volumetric inputs from periodic rainfall were not the major recharge mechanism. Sampling which included an overbank flooding event in March 2012 provided firm evidence for groundwater originating from high flow episodic river recharge. The use of long-term environmental data to understand how economically important water resources respond to climate change with increasing temperatures is considered essential for future sustainability.

18. Analytical potential energy surface and kinetics of the NH(3) + H --> NH(2) + H(2) hydrogen abstraction and the ammonia inversion reactions.

PubMed

2010-04-01

Based on accurate electronic structure calculations, a new analytical potential energy surface (PES) was fitted to simultaneously describe the hydrogen abstraction reaction from ammonia by a hydrogen atom, and the ammonia inversion. Using a wide spectrum of properties of the reactive system (equilibrium geometries, vibrational frequencies, and relative energies of the stationary points, topology of the reaction paths, and points on the reaction swaths) as reference, the resulting analytical PES reproduces reasonably well the input ab initio information obtained at the CCSD(T)/cc-pVTZ level, which represents a severe test for the new surface. As a first application, on this analytical PES we perform an extensive kinetics study using variational transition-state theory with semiclassical transmission coefficients over a wide temperature range, 200-2000 K. For the hydrogen abstraction reaction, the forward rate constants reproduce the experimental measurements, while the reverse ones are slightly underestimated. Another severe test of the new surface is the analysis of the kinetic isotope effects (KIEs). The KIEs between unsubstituted and all deuterated reactions agree with experiment in the common temperature range. For the ammonia inversion reaction, the splitting of the degenerate vibrational levels of the double well due to the tunneling contribution, which is very important in this reaction representing 93% of the reactivity at 200 K, was calculated for the NH(3) and ND(3) species. The values found were 3.6 and 0.37 cm(-1), respectively, which although higher than experimental values, reproduce the experimental behavior on isotopic substitution.

19. Water-Isotopes (2H, 3H, 18O) to trace the source and timing of recharge in a fractured granite aquifer in Western Kenya, Africa

Kralik, Martin; Whylidal, Stefan; Asunah, Francis; Sültenfuß, Jürgen

2014-05-01

The Vihiga District in West Kenya North-West of Lake Victoria is one of the most densely populated areas in Kenya with 1033 person per square kilometer. To find the most suitable location of an own well for a Primary School in this district, springs, school wells and creeks were sampled in the surroundings to get information about the hydrological cycle in the area. The Waluka Primary school (0.02134°N, 34.64311°E) is situated on the northern slope of the Maragoli Hills 20 km to the North-West of the Nyanzan provincial capital of Kisumu at the eastern shore of Lake Victoria. The hilly relief varies between 1535 - 1675m. The yearly precipitation is between 1200-1600 mm/a (23°C mean temperature) with biannual rainy seasons in which the long rains are generally from March to May as the Inter-Tropical Convergence Zone (ITCZ) moves northwards, and the short rains are typically from October to December as the ITCZ retreats southwards. A lateritic soil covers a thin alteration zone above the Precambrian Maragoli-Granite (Saggerson, 1952). Water circulates either in the thin alteration zone or in fault zones cutting through the Precambrian granite. From discharge measurements of two springs and a creek at the end of the dry season (February 2012) a minimum discharge of ca. 10-20 L/s km2 (300-600 mm) can be estimated. The water is of the alkaline sulfate-nitrate type with low mineralization (70-150 μ S/cm, 25°C) and a low pH of about 5 to 6. The delta oxygen-18 and deuterium value ranges between -2.84 to -1.98 oand -8.5 to - 3.9 o(VSMOW). The deuterium excess ranges from 11.7-14.2 oThe water of one spring and well close to the school have a tritium content of 1.42 - 1.62 TU. All groundwater has a low arsenium, fluorine and uranium content, which had only a short soil passage. The relatively elevated, but not problematic content in nitrate (10 - 16 mg/L) probaly reflects the intensive agricultural activities in this area. As the mean δ 18O values during the rainy seasons are significantly lower (-3 to -4 o) than in the mean precipitation during the rest of the year (-2.5 to -1.9 o; Mwango, 2003) one can conclude that the main spring 'Anzaya' and the well in the Naboka Secondary School are recharged from deeper faults with water supplied more during the rainy season. The slightly higher d-excess of 13.4-14.2 ocompared to 11.7-12.6 oin the rest of the samples, indicates a somewhat higher recharge area of this two sites with water vapor recycled in the precipitation around the Liailhunuu peak (ca. 1675m). This effect is also supported by spring-water measurements at the Kilimanjaro (d-excess 13.4-6.6 o) 400 km SE. Similarily, the tritium content of 1.42 - 1.62 TU indicate that compared to a mean tritium content of 2 TU in the rain of this area (Mwango, 2003) the mean residence time can be in the range of recent to few years only.

20. SPATIALLY RESOLVED l-C{sub 3}H{sup +} EMISSION IN THE HORSEHEAD PHOTODISSOCIATION REGION: FURTHER EVIDENCE FOR A TOP-DOWN HYDROCARBON CHEMISTRY

SciTech Connect

Guzmán, V. V.; Öberg, K. I.; Pety, J.; Goicoechea, J. R.; Gerin, M.; Roueff, E.; Gratier, P.

2015-02-20

Small hydrocarbons, such as C{sub 2}H, C{sub 3}H, and C{sub 3}H{sub 2} are more abundant in photo-dissociation regions (PDRs) than expected based on gas-phase chemical models. To explore the hydrocarbon chemistry further, we observed a key intermediate species, the hydrocarbon ion l-C{sub 3}H{sup +}, in the Horsehead PDR with the Plateau de Bure Interferometer at high-angular resolution (6″). We compare with previous observations of C{sub 2}H and c-C{sub 3}H{sub 2} at similar angular resolution and new gas-phase chemical model predictions to constrain the dominant formation mechanisms of small hydrocarbons in low-UV flux PDRs. We find that at the peak of the HCO emission (PDR position), the measured l-C{sub 3}H{sup +}, C{sub 2}H, and c-C{sub 3}H{sub 2} abundances are consistent with current gas-phase model predictions. However, in the first PDR layers, at the 7.7 μm polycyclic aromatic hydrocarbon band emission peak, which are more exposed to the radiation field and where the density is lower, the C{sub 2}H and c-C{sub 3}H{sub 2} abundances are underestimated by an order of magnitude. At this position, the l-C{sub 3}H{sup +} abundance is also underpredicted by the model but only by a factor of a few. In addition, contrary to the model predictions, l-C{sub 3}H{sup +} peaks further out in the PDR than the other hydrocarbons, C{sub 2}H and c-C{sub 3}H{sub 2}. This cannot be explained by an excitation effect. Current gas-phase photochemical models thus cannot explain the observed abundances of hydrocarbons, in particular, in the first PDR layers. Our observations are consistent with a top-down hydrocarbon chemistry, in which large polyatomic molecules or small carbonaceous grains are photo-destroyed into smaller hydrocarbon molecules/precursors.

1. Spatially Resolved L-C3H+ Emission in the Horsehead Photodissociation Region: Further Evidence for a Top-Down Hydrocarbon Chemistry

Guzmán, V. V.; Pety, J.; Goicoechea, J. R.; Gerin, M.; Roueff, E.; Gratier, P.; Öberg, K. I.

2015-02-01

Small hydrocarbons, such as C2H, C3H, and C3H2 are more abundant in photo-dissociation regions (PDRs) than expected based on gas-phase chemical models. To explore the hydrocarbon chemistry further, we observed a key intermediate species, the hydrocarbon ion l-C3H+, in the Horsehead PDR with the Plateau de Bure Interferometer at high-angular resolution (6″). We compare with previous observations of C2H and c-C3H2 at similar angular resolution and new gas-phase chemical model predictions to constrain the dominant formation mechanisms of small hydrocarbons in low-UV flux PDRs. We find that at the peak of the HCO emission (PDR position), the measured l-C3H+, C2H, and c-C3H2 abundances are consistent with current gas-phase model predictions. However, in the first PDR layers, at the 7.7 μm polycyclic aromatic hydrocarbon band emission peak, which are more exposed to the radiation field and where the density is lower, the C2H and c-C3H2 abundances are underestimated by an order of magnitude. At this position, the l-C3H+ abundance is also underpredicted by the model but only by a factor of a few. In addition, contrary to the model predictions, l-C3H+ peaks further out in the PDR than the other hydrocarbons, C2H and c-C3H2. This cannot be explained by an excitation effect. Current gas-phase photochemical models thus cannot explain the observed abundances of hydrocarbons, in particular, in the first PDR layers. Our observations are consistent with a top-down hydrocarbon chemistry, in which large polyatomic molecules or small carbonaceous grains are photo-destroyed into smaller hydrocarbon molecules/precursors. Based on observations obtained with the IRAM Plateau de Bure interferometer and 30 m telescope. IRAM is supported by INSU/CNRS (France), MPG (Germany), and IGN (Spain).

2. Effects of linalool on [(3)H]MK801 and [(3)H] muscimol binding in mouse cortical membranes.

PubMed

Brum, L F; Elisabetsky, E; Souza, D

2001-08-01

Linalool is a monoterpene compound reported to be a major component of essential oils of several aromatic species. Several linalool-producing species are used in traditional medical systems for sedative purposes, including the interruption and prevention of seizures. Previous studies in mice revealed that linalool modulates glutamatergic (competitive antagonism of L-[(3)H]glutamate binding, delayed intraperitoneal NMDA-induced convulsions and blockade of intracerebroventricular Quin-induced convulsions) and GABAergic transmission (protection against pentylenetetrazol and picrotoxin-induced convulsions). To further clarify the anticonvulsive mechanisms of linalool, we studied the effects of linalool on binding of [(3)H]MK801 (NMDA antagonist) and [(3)H]muscimol (GABA(A) agonist) to mouse cortical membranes. Linalool showed a dose dependent non-competitive inhibition of [(3)H]MK801 binding (IC(50) = 2.97 mM) but no effect on [(3)H]muscimol binding. The data suggest that the anticonvulsant mode of action of linalool includes a direct interaction with the NMDA receptor complex. The data do not, however, support a direct interaction of linalool with GABA(A) receptors, although changes in GABA-mediated neuronal inhibition or effects on GABA release and uptake cannot be ruled out.

3. Synthesis of novel biologically active heterocyclic compounds from 2-oxo-2H-benzopyran-6-yl-imidazolidine.

PubMed

2011-01-01

6-Aminocoumarin on treatment with oxalyl chloride gives coumarinyl-6-isocynate (1a-c) which on treatment with glycine gives 1H-3-[2'-oxo-2'H-benzopyran-6'-yl]-5-imidazolidine-2, 4-dione (2a-c). (2a-c) when refluxed with o-chlorobenzaldehyde, m-hydroxybenzaldehyde, 3,4-dimethoxybenzaldehyde and 3-nitrobenzaldehyde separately gives 1H-5-(2"-chlorobenzylidene)-3-(2'-oxo-2'H-benzopyran-6'-yl) imidazolidine-2,4-dione (3a-c), 1H-5-(3"-hydroxybenzylidene)-3-(2'-oxo-2'H-benzopyran-6'-yl) imidazolidine-2,4-dione (4a-c), 1H-5-(3",4"-dimethoxybenzylidene)-3-(2'-oxo-2'H-benzopyran-6'-yl) imidazolidine-2,4-dione (5a-c) and 1H-5-(3"-nitrobenzylidene)-3-(2'-oxo-2'H-benzopyran-6'-yl) imidazolidine-2,4-dione (6a-c), respectively. 3-(2"-Chlorophenyl)-3a,4-dihydro-6-(2'-oxo-2'H-benzopyran-6'-yl) imidazo[4,5-c]isoxazol-5-one 7a-c is obtained from (3a-c) and hydroxylamine hydrochloride while 2,3a,4-trihydro-3-(3"-hydroxyphenyl)-6-(2'-oxo-2'H-benzopyran-6'-yl) imidazo[4,5-c]pyrazol-5-one (8a-c) obtained by reaction of (4a-c) with hydrazine hydrate. Compound (5a-c) on treatment with urea gives 5,7-dihydro-2-hydroxy-6-(3",4"-dimethoxyphenyl)-9-(2'-oxo-2'H-benzopyran-6'-yl) purin-8-one (9a-c) and compound (6a-c) on treatment with thiourea gives 5,7-dihydro-2-mercapto-6-(3"-nitrophenyl)-9-(2'-oxo-2'H-benzopyran-6'-yl)purin-8-one (10a-c). The structures of the compounds have been established on the basis of spectral analytical data. All the compounds have been screened for their antimicrobial activities against three bacterial strains S. aureus, S. typhi and E. coli. Compounds 2b, 3b, 4b, 5b, 6b, 7b, 8b, 9b and 10b with the presence of methyl groups at C7' and C8' of coumarin moiety were found to be more active than others.

4. Association reactions at low pressure. III. The C2H2+/C2H2 system.

PubMed

Anicich, V G; Sen, A D; Huntress, W T; McEwan, M J

1990-11-15

The association reactions, C4H2(+) + C2H2 and C4H3(+) + C2H2 have been examined at pressures between 8 x 10(-8) and 1 x 10(-4) Torr at 298 K in an ion cyclotron resonance mass spectrometer. Association occurred via two different mechanisms. At pressures below approximately 2 x 10(-6) Torr, the association was bimolecular having rate coefficients k2 = 2.7 x 10(-10) cm3 s-1 and 2.0 x 10(-10) cm3 s-1 for C4H2+ and C4H3+, respectively. At pressures above approximately 2 x 10(-6) Torr, termolecular association was observed with rate coefficients, k3 = 5.7 x 10(-23) cm6 s-1 and 1.3 x 10(-23) cm6 s-1 for C4H2+ and C4H3+, respectively, when M = C2H2. The termolecular rate constants with N2, Ar, Ne, and He as the third body, M, are also reported. We propose that the low pressure bimolecular association process was the result of radiative stabilization of the complex and the termolecular association process was the result of collisional stabilization. Elementary rate coefficients were obtained and the lifetime of the collision complex was > or = 57 microseconds for (C6H4+)* and > or = 18 microseconds for (C6H5+)*. At pressures below 1 x 10(-6) Torr, approximately 11% of the (C6H4+)* were stabilized by photon emission and the remaining approximately 89% reverted back to reactants, while approximately 24% of the (C6H5+)* were stabilized by photon emission and the remaining approximately 76% reverted back to reactants. The ionic products of the C2H2(+) + C2H2 reaction, C4H2+ and C4H3+, were found to be formed with enough internal energy that they did not react by the radiative association channel until relaxed by several nonreactive collisions with the bath gas.

5. Structure–function studies of histone H3/H4 tetramer maintenance during transcription by chaperone Spt2

DOE PAGES

Chen, Shoudeng; Rufiange, Anne; Huang, Hongda; ...

2015-06-15

Cells use specific mechanisms such as histone chaperones to abrogate the inherent barrier that the nucleosome poses to transcribing polymerases. The current model postulates that nucleosomes can be transiently disrupted to accommodate passage of RNA polymerases and that histones H3 and H4 possess their own chaperones dedicated to the recovery of nucleosomes. Here, we determined the crystal structure of the conserved C terminus of human Suppressors of Ty insertions 2 (hSpt2C) chaperone bound to an H3/H4 tetramer. The structural studies demonstrate that hSpt2C is bound to the periphery of the H3/H4 tetramer, mimicking the trajectory of nucleosomal-bound DNA. These structuralmore » studies have been complemented with in vitro binding and in vivo functional studies on mutants that disrupt key intermolecular contacts involving two acidic patches and hydrophobic residues on Spt2C. We show that contacts between both human and yeast Spt2C with the H3/H4 tetramer are required for the suppression of H3/ H4 exchange as measured by H3K56ac and new H3 deposition. Furthermore, these interactions are also crucial for the inhibition of spurious transcription from within coding regions. In conclusion, together, our data indicate that Spt2 interacts with the periphery of the H3/H4 tetramer and promotes its recycling in the wake of RNA polymerase.« less

6. Structure–function studies of histone H3/H4 tetramer maintenance during transcription by chaperone Spt2

SciTech Connect

Chen, Shoudeng; Rufiange, Anne; Huang, Hongda; Rajashankar, Kanagalaghatta R.; Nourani, Amine; Patel, Dinshaw J.

2015-06-15

Cells use specific mechanisms such as histone chaperones to abrogate the inherent barrier that the nucleosome poses to transcribing polymerases. The current model postulates that nucleosomes can be transiently disrupted to accommodate passage of RNA polymerases and that histones H3 and H4 possess their own chaperones dedicated to the recovery of nucleosomes. Here, we determined the crystal structure of the conserved C terminus of human Suppressors of Ty insertions 2 (hSpt2C) chaperone bound to an H3/H4 tetramer. The structural studies demonstrate that hSpt2C is bound to the periphery of the H3/H4 tetramer, mimicking the trajectory of nucleosomal-bound DNA. These structural studies have been complemented with in vitro binding and in vivo functional studies on mutants that disrupt key intermolecular contacts involving two acidic patches and hydrophobic residues on Spt2C. We show that contacts between both human and yeast Spt2C with the H3/H4 tetramer are required for the suppression of H3/ H4 exchange as measured by H3K56ac and new H3 deposition. Furthermore, these interactions are also crucial for the inhibition of spurious transcription from within coding regions. In conclusion, together, our data indicate that Spt2 interacts with the periphery of the H3/H4 tetramer and promotes its recycling in the wake of RNA polymerase.

7. R-matrix description of particle energy spectra produced by low-energy 3H + 3H reactions

DOE PAGES

Brune, C. R.; Caggiano, J. A.; Sayre, D. B.; ...

2015-07-20

An R-matrix model for three-body final states is presented and applied to a recent measurement of the neutron energy spectrum from the 3H + 3H→ 2n + α reaction. The calculation includes the n alpha and n n interactions in the final state, angular momentum conservation, antisymmetrization, and the interference between different channels. A good fit to the measured spectrum is obtained, where clear evidence for the 5He ground state is observed. The model is also used to predict the alpha-particle spectrum from 3H + 3H as well as particle spectra from 3He + 3He. The R-matrix approach presented heremore » is very general, and can be adapted to a wide variety of problems with three-body final states.« less

8. Lanthanide complexes of 3-acetyl-4-hydroxy-6-methyl-2H-pyran-2-one

SciTech Connect

Sitran, S; Fregona, D. ); Faraglia, G. )

1990-01-01

The title ligand (H(Dh), dehydroacetic acid) reacts with lanthanide(III) acetates in anhydrous methanol to form complexes of formula (M(Dh){sub 3}(MeOH)). When hydrated lanthanide acetates are used, hydrated compounds such as (Ce(Dh){sub 3}(H{sub 2}O)) or (Eu(Dh){sub 3}(H{sub 2}O)).H{sub 2}O are obtained. The reaction of lanthanum triacetate with H(Dh) yields the mixed complex (La(Dh){sub 2}(O{sub 2}CMe)), formation of the 1:3 complex also being unfavored in the presence of a large ligand excess. The complexes have been characterized by infrared and NMR ({sup 1}H and {sup 13}C) spectroscopy and by thermogravimetric measurements.

9. [Pharmacokinetics and biodistribution of 3H-norcantharidin in mice].

PubMed

Wei, Chun-Min; Wang, Ben-Jie; Ma, Ya; Sun, Zi-Ping; Li, Xiao-Li; Guo, Rui-Chen

2007-05-01

10. Crystal structure of 2-methyl-1H-imidazol-3-ium hydrogen oxalate dihydrate

PubMed Central

Diop, Mouhamadou Birame; Diop, Libasse; Plasseraud, Laurent; Cattey, Hélène

2016-01-01

Single crystals of the title mol­ecular salt, C4H7N2 +·HC2O4 −·2H2O, were isolated from the reaction of 2-methyl-1H-imidazole and oxalic acid in a 1:1 molar ratio in water. In the crystal, the cations and anions are positioned alternately along an infinite [010] ribbon and linked together through bifurcated N—H⋯(O,O) hydrogen bonds. The water mol­ecules of crystallization link the chains into (10-1) bilayers, with the methyl groups of the cations organized in an isotactic manner. PMID:27536393

11. Rabbit blastocysts accumulate (/sup 3/H)prostaglandins in vitro

SciTech Connect

Jones, M.A.; Harper, M.J.

1984-08-01

Rabbit blastocysts obtained on days 5, 6, and 6.8 of pregnancy were incubated in vitro in Tyrode's buffer with /sup 3/H-labeled prostaglandins (PGs). Accumulation of PGs was studied, using Whatman GF/F filters to separate bound and free ligands. The uptake and efflux of (/sup 3/H)PGs were studied as a function of PG type, incubation time, temperature, and effect of metabolic inhibitors as well as age and number of blastocysts. Blastocysts of the same age accumulated approximately the same amount of (/sup 3/H)PGE2 and (/sup 3/H)PGF2 alpha from their environment; however, there was no apparent saturation over a PG concentration range of 1-1000 nM. Both the uptake and efflux of PG were age dependent, with older blastocysts accumulating more PGs. Approximately 90% of the (/sup 3/H)PGs appear to be transported into the blastocoelic fluid, with little PG remaining in the blastomeres. PG accumulation was relatively insensitive to azide, ouabain, cyanide, or bromcresol green, but was affected by incubation at 0 C or the addition of indomethacin (10 micrograms/ml). No catabolism of the accumulated PGs was observed. The release of PGE2 in general did not differ from that of PGF2 alpha, except on day 6.8 of pregnancy when PGE2 was released more rapidly than on day 6. The authors conclude that rabbit blastocysts can accumulate PGs from their environment, which may imply a storage potential in the blastocyst and release before implantation.

12. The Chemistry of Mesitylgallium(3) Derivatives as Arene Ligands in Metal Carbonyl Complexes. Crystal and Molecular Structures of ((CO)3Mo(Eta 6- C6Me3H2))Ga(C6Me3H2)2 and ((CO)3Mo(Eta 6-C6Me3H2))2GA(C6Me3H2)

DTIC Science & Technology

1988-12-16

useful neutral 6 6 6amphoteric ligands include PhB (NMe2 )2 , PhB (OMe)2 , PhB (C 5Ho10 ) and PhB (CH2CH(Me)C2H4 ) 6 . An anionic arene-transition metal...recrystallized from an appropriate solvent system. Synthesis of [(CO)3MoNes]2Ga~es. The complex [(CO) 3MoMes]2GaMes was prepared by refluxing a...2.22 (s, p-Me, 3 H); IR (DME, v(CO), cm- I) 1960 (sh, s), 1951 (vs), 1879 (vs). Anal. Caled: C, 50.35; H, 4.22. Found: C, 50.56; H, 4.24. Synthesis

13. The composition of Saturn's atmosphere at northern temperate latitudes from Voyager IRIS spectra - NH3, PH3, C2H2, C2H6, CH3D, CH4, and the Saturnian D/H isotopic ratio

NASA Technical Reports Server (NTRS)

Courtin, R.; Gautier, D.; Marten, A.; Bezard, B.; Hanel, R.

1984-01-01

The vertical distributions and mixing ratios of minor constituents in the northern hemisphere of Saturn are investigated. Results are obtained for NH3, PH3, C2H2, C2H6, CH3D, and CH4; the D/H ratio is obtained from the CH4 and CH3D abundances. The NH3 mixing ratio in the upper atmosphere is found to be compatible with the saturated partial pressure. The inferred PH3/H2 ratio of 1.4 + or - 0.8 x 10 to the -6th is higher than the value derived from the solar P/H ratio. The stratospheric C2H2/H2 and C2H6/H2 ratios are, respectively, 2.1 + or - 1.4 x 10 to the -7th and 3.0 + or - 1.1 x 10 to the -6th; the latter decreases sharply below the 20-50 mbar level. The results for CH3D/H2 and CH4/H2 imply an enrichment of Saturn's upper atmosphere in carbon by a factor of at least three over the solar abundance. The interpretation of two NH3 lines in the five-micron window suggests a NH3/H2 ratio at the two bar level below the solar value.

14. Partial phase diagram for the system NH3-H2O - The water-rich region

NASA Technical Reports Server (NTRS)

Johnson, M. L.; Schwake, A.; Nicol, M.

1984-01-01

Phase boundaries of the H2O-NH3 system for (NH3)/x/(H2O)/1-x/ have been determined with diamond-anvil cells for mixtures in two composition ranges: (1) for x in the range from 0 to 0.3, at pressures up to 4 GPa at 21 C, and (2) for x in the range from 0.46 to 0.50, at pressures up to 5 GPa from 150 to 400 K. Phases were identified visually with a microscope and polarized optics. The NH3.2(H2O) phase is strongly anisotropic with a much smaller refractive index than that of ice VII and cracks in two nonperpendicular networks. NH3.H2O has a refractive index closer to that of Ice VII and does not appear to form cracks. Both phases are colorless. Phase boundaries were determined on both increasing and decreasing pressures, and compositions of the ammonia ices were determined by estimating relative amounts of water and ammonia ices at known overall compositions. For low-ammonia compositions (x equal to or less than 0.15), the following assemblages succedd one another as pressure increases: liquid; liquid and Ice VI (at 1.0 + GPa); liquid and Ice VII (at 2.1 GPa); Ice VII and NH3.H2O (at 3.5 GPa). For x in the range from 0.15 to 0.30, the water ice and liquid fields are replaced by the NH3.2(H2O) and liquid field at pressures down to 1.0 GPa and lower.

15. Synthesis and characterization of d{sup 10} metal complexes with mixed 1,3-di(1H-imidazol-4-yl)benzene and multicarboxylate ligands

SciTech Connect

Chen, Zhi-Hao; Zhao, Yue; Chen, Shui-Sheng; Wang, Peng; Sun, Wei-Yin

2013-06-15

Seven new coordination polymers [Zn(H{sub 2}L)(mbdc)] (1), [Zn(H{sub 3}L)(btc)] (2), [Zn(H{sub 2}L)(Hbtc)] (3), [Zn(H{sub 2}L)(Hbtc)]·H{sub 2}O (4), [Zn{sub 2}(H{sub 2}L)(btc)(μ{sub 2}-OH)] (5), [Cd(H{sub 2}L)(mbdc)] (6) and [Cd{sub 3}(H{sub 2}L){sub 2}(btc){sub 2}(H{sub 2}O)]·5H{sub 2}O (7) were synthesized by reactions of the corresponding metal salt with rigid ligand 1,3-di(1H-imidazol-4-yl)benzene (H{sub 2}L) and different carboxylic acids of 1,3-benzenedicarboxylic acid (H{sub 2}mbdc) and benzene-1,3,5-tricarboxylic acid (H{sub 3}btc), respectively. The results of X-ray crystallographic analysis indicate that complex 1 is 1D chain while 2 is a (3,3)-connected 2D network with Point (Schläfli) symbol of (4,8{sup 2}). Complexes 3 and 6 are 2D networks, 4 is a 3-fold interpenetrating 3D framework with Point (Schläfli) symbol of (6{sup 5},8) and 5 is a (3,8)-connected 2D network with Point (Schläfli) symbol of (3,4{sup 2}){sub 2}(3{sup 4},4{sup 6},5{sup 6},6{sup 8},7{sup 3},8), while 7 is a (3,10)-connected 3D net with Schläfli symbol of (3,4,5){sub 2}(3{sup 4},4{sup 8},5{sup 18},6{sup 12},7{sup 2},8). The thermal stability and photoluminescence of the complexes were investigated. Furthermore, DFT calculations were performed for 2–4 to discuss the temperature controlled self-assembly of the complexes. - Graphical abstract: Seven new coordination polymers with multicarboxylate and rigid ditopic 4-imidazole containing ligands have been obtained and found to show different structures and topologies. - Highlights: • Metal complexes with diverse structures of 1D chain, 2D network and 3D framework. • Mixed ligands of 1,3-di(1H-imidazol-4-yl)benzene and multicarboxylate. • Photoluminescence property.

16. Reactions of Fe+ and FeO+ with C2H2, C2H4, and C2H6: temperature-dependent kinetics.

PubMed

Ard, Shaun G; Melko, Joshua J; Fournier, Joseph A; Shuman, Nicholas S; Viggiano, Albert A

2013-10-10

We present the first temperature-dependent rate constants and branching ratios for the reactions of Fe(+) and FeO(+) with C2H2, C2H4, and C2H6 from 170 to 700 K. Fe(+) is observed to react only by association with the three hydrocarbons, with temperature dependencies of T(-2) to T(-3). FeO(+) reacts with C2H2 and C2H4 at the collision rate over the temperature range, and their respective product branchings show similar temperature dependences. In contrast, the reaction with ethane is collisional at 170 K but varies as T(-0.5), while the product branching remains essentially flat with temperature. These variations in reactivity are discussed in terms of the published reactive potential surfaces. The effectiveness of Fe(+) as an oxygen-transfer catalyst toward the three hydrocarbons is also discussed.

17. Collisions of slow polyatomic ions with surfaces: dissociation and chemical reactions of C2H2+*, C2H3+, C2H4+*, C2H5+, and their deuterated variants C2D2+* and C2D4+* on room-temperature and heated carbon surfaces.

PubMed

Jasík, Juraj; Zabka, Jan; Feketeova, Linda; Ipolyi, Imre; Märk, Tilmann D; Herman, Zdenek

2005-11-17

Interaction of C2Hn+ (n = 2-5) hydrocarbon ions and some of their isotopic variants with room-temperature and heated (600 degrees C) highly oriented pyrolytic graphite (HOPG) surfaces was investigated over the range of incident energies 11-46 eV and an incident angle of 60 degrees with respect to the surface normal. The work is an extension of our earlier research on surface interactions of CHn+ (n = 3-5) ions. Mass spectra, translational energy distributions, and angular distributions of product ions were measured. Collisions with the HOPG surface heated to 600 degrees C showed only partial or substantial dissociation of the projectile ions; translational energy distributions of the product ions peaked at about 50% of the incident energy. Interactions with the HOPG surface at room temperature showed both surface-induced dissociation of the projectiles and, in the case of radical cation projectiles C2H2+* and C2H4+*, chemical reactions with the hydrocarbons on the surface. These reactions were (i) H-atom transfer to the projectile, formation of protonated projectiles, and their subsequent fragmentation and (ii) formation of a carbon chain build-up product in reactions of the projectile ion with a terminal CH3-group of the surface hydrocarbons and subsequent fragmentation of the product ion to C3H3+. The product ions were formed in inelastic collisions in which the translational energy of the surface-excited projectile peaked at about 32% of the incident energy. Angular distributions of reaction products showed peaking at subspecular angles close to 68 degrees (heated surfaces) and 72 degrees (room-temperature surfaces). The absolute survival probability at the incident angle of 60 degrees was about 0.1% for C2H2+*, close to 1% for C2H4+* and C2H5+, and about 3-6% for C2H3+.

18. The structure of the 1H-imidazol-3-ium lawsonate salt aided by ab initio gas-phase calculations.

PubMed

Ribeiro, Marcos Antônio; Oliveira, Willian Xerxes Coelho; Stumpf, Humberto Osório; Pinheiro, Carlos Basílio

2013-04-01

For the new organic salt 1H-imidazol-3-ium 1,4-dioxo-1,4-dihydronaphthalen-2-olate, C3H5N2(+)·C10H5O3(-), ab initio calculations of the gas-phase structures of the lawsonate and imidazolium ions were performed to help in the interpretation of the structural features observed. Three different types of hydrogen bond are responsible for the three-dimensional packing of the salt.

19. Organocatalytic asymmetric Henry reaction of 1H-pyrrole-2,3-diones with bifunctional amine-thiourea catalysts bearing multiple hydrogen-bond donors

PubMed Central

Zhang, Ming-Liang; Yue, Deng-Feng; Wang, Zhen-Hua; Luo, Yuan; Zhang, Xiao-Mei

2016-01-01

Summary For the first time, a catalytic asymmetric Henry reaction of 1H-pyrrole-2,3-diones was achieved with a chiral bifunctional amine-thiourea as a catalyst possessing multiple hydrogen-bond donors. With this developed method, a range of 3-hydroxy-3-nitromethyl-1H-pyrrol-2(3H)-ones bearing quaternary stereocenters were obtained in acceptable yield (up to 75%) and enantioselectivity (up to 73% ee). PMID:26977188

20. Rate constant for the reaction C2H5 + HBr → C2H6 + Br.

PubMed

Golden, David M; Peng, Jingping; Goumri, A; Yuan, J; Marshall, Paul

2012-06-21

RRKM theory has been employed to analyze the kinetics of the title reaction, in particular, the once-controversial negative activation energy. Stationary points along the reaction coordinate were characterized with coupled cluster theory combined with basis set extrapolation to the complete basis set limit. A shallow minimum, bound by 9.7 kJ mol(-1) relative to C(2)H(5) + HBr, was located, with a very small energy barrier to dissociation to Br + C(2)H(6). The transition state is tight compared to the adduct. The influence of vibrational anharmonicity on the kinetics and thermochemistry of the title reaction were explored quantitatively. With adjustment of the adduct binding energy by ∼4 kJ mol(-1), the computed rate constants may be brought into agreement with most experimental data in the literature, including new room-temperature results described here. There are indications that at temperatures above those studied experimentally, the activation energy may switch from negative to positive.

1. Rate Coefficients of C2H with C2H4, C2H6, and H2 from 150 to 359 K

NASA Technical Reports Server (NTRS)

Opansky, Brian J.; Leone, Stephen R.

1996-01-01

Rate coefficients for the reactions C2H with C2H4, C2H6, and H2 are measured over the temperature range 150-359 K using transient infrared laser absorption spectroscopy. The ethynyl radical is formed by photolysis of C2H2 with a pulsed excimer laser at 193 nm, and its transient absorption is monitored with a color center laser on the Q(sub 11)(9) line of the A(sup 2) Pi-Chi(sup 2) Sigma transition at 3593.68 cm(exp -1). Over the experimental temperature range 150-359 K the rate constants of C2H with C2H4, C2H6, and H2 can be fitted to the Arrhenius expressions k(sub C2H4) = (7.8 +/- 0.6) x 10(exp -11) exp[(134 +/- 44)/T], k(sub C2H6) = (3.5 +/- 0.3) x 10(exp -11) exp[(2.9 +/- 16)/T], and k(sub H2) = (1.2 +/- 0.3) x 10(exp -11) exp[(-998 +/- 57)]/T cm(exp 3) molecule(exp -1) sec(exp -1). The data for C2H with C2H4 and C2H6 indicate a negligible activation energy to product formation shown by the mild negative temperature dependence of both reactions. When the H2 data are plotted together with the most recent high-temperature results from 295 to 854 K, a slight curvature is observed. The H2 data can be fit to the non-Arrhenius form k(sub H2) = 9.2 x 10(exp -18) T(sup 2.17 +/- 0.50) exp[(-478 +/- 165)/T] cm(exp 3) molecules(exp -1) sec(exp -1). The curvature in the Arrhenius plot is discussed in terms of both quantum mechanical tunneling of the H atom from H2 to the C2H radical and bending mode contributions to the partition function.

2. Conformational changes in the H3. H4 histone complex

SciTech Connect

Feldman, L.; Beaudette, N.V.; Stollar, B.D.; Fasman, G.D.

1980-08-10

The H3.H4 complex has been extracted from calf thymus chromatin in either 0.05 M NaOAc, pH 5.0, or in 2.0 M KCl, 0.1 M KPO/sub 4/, pH 6.7, and both forms have been shown to consist solely of histones H3 and H4 when examined on sodium dodecyl sulfate-polyacrylamide gels. Serological and circular dichroism analyses indicate the existence of structural differences between the two forms. Dilution of the high salt form of the complex into low salt produces a time-dependent conformational change which is related to reduction in the ..cap alpha.. helix content of the complex and which exposes antigenic sites on the complex. The existence of multiple forms of the H3.H4 complex may be related to the dynamic equilibrium of nucleosome structure in vivo.

3. Silver-Catalyzed C(sp(3))-H Chlorination.

PubMed

Ozawa, Jun; Kanai, Motomu

2017-03-17

A silver-catalyzed chlorination of benzylic, tertiary, and secondary C(sp(3))-H bonds was developed. The reaction proceeded with as low as 0.2 mol % catalyst loading at room temperature under air atmosphere with synthetically useful functional group compatibility. The regioselectivity and reactivity tendencies suggest that the chlorination proceeded through a radical pathway, but an intermediate alkylsilver species cannot be ruled out.

4. Synthesis of 2-Alkenyl-2H-indazoles from 2-(2-Carbonylmethyl)-2H-indazoles.

PubMed

Lin, Mei-Huey; Liang, Kung-Yu; Tsai, Chang-Hsien; Chen, Yu-Chun; Hsiao, Hung-Chang; Li, Yi-Syuan; Chen, Chung-Hao; Wu, Hau-Chun

2016-02-19

A procedure has been developed for synthesis of 2-alkenyl-2H-indazoles starting from 2-(2-carbonylmethyl)-2H-indazoles, which are prepared by gallium/aluminium- and aluminium-mediated, direct, regioselective alkylation of indazoles with α-bromocarbonyl compounds. The structure of 3-(2H-indazol-2-yl)-2H-chromen-2-one was proven by X-ray crystallography. The styrene- and coumarin-2H-indazoles produced by using the new method were found to have interesting fluorescence properties.

5. Quantitation of methadone enantiomers in humans using stable isotope-labeled (2H3)-, (2H5)-, and (2H8)Methadone

SciTech Connect

Nakamura, K.; Hachey, D.L.; Kreek, M.J.; Irving, C.S.; Klein, P.D.

1982-01-01

6. (/sup 3/H)nitrendipine binding to adrenal capsular membranes

SciTech Connect

Finkel, M.S.; Aguilera, G.; Catt, K.J.; Keiser, H.R.

1984-08-20

The physiologic regulation of aldosterone secretion is dependent on extracellular calcium and appears to be mediated by increases in cytosolic free calcium concentration in the zona glomerulosa cell. A specific role for voltage-dependent calcium channels was suggested by previous studies with the calcium channel antagonist verapamil. The authors therefore studied the (/sup 3/H)nitrendipine calcium channel binding site in adrenal capsules. These studies revealed a single class of saturable, high affinity sites with K/sub D/ = .26 +/- .04 nM and B/sub max/ = 105 +/- 5.7 fmol/mg protein. Specific binding of (/sup 3/H)nitrendipine was inhibited by calcium channel antagonists with potencies nitrendipine = nifedipine >> verapamil, while diltiazem had no inhibitory effect. In the rat, binding sites for (/sup 3/H)nitrendipine were located in the adrenal capsule and medulla and were undetectable in the zona fasciculata. Physiologic studies with collagenase-dispersed adrenal glomerulosa cells demonstrated that nifedipine selectively inhibited angiotensin-II and potassium-stimulated steroidogenesis. These observations suggest both a pharmacologic and physiologic role for the nitrendipine binding site in aldosterone production. 17 references, 2 figures, 1 table.

7. Preformance Analysis of NH3-H2O Absorption Cycle

Tsujimori, Atsushi; Ozaki, Eiichi

Different from H2O-LiBr absorption cycle, it is necessary to have rectifier between generator and condenser in NH3-H2O absorption cycle, because there mixes some steam in refrigerant vapor in the process of regenerating refrigerant from the ammonia strong aqueous solution. And in some case ex. partial load or heating, the efficiency of rectifier might decrease, if the flow rate of refrigerant vapor and ammonia aqueous solution decrease. As a result, steam flow into condenser with ammonia refrigerant vapor, which reduces cycle COPs of cooling and heating. Accordingly in order to evaluate the effect of ammonia concentration in refrigerant for the performance of NH3-H2O absorption heat pump, the simple design approach of modeling condenser and evaporator is introduced in this paper. In the model, the calculation of heat rate in condenser and evaporator was simplified considering the characteristic of NH3-H2O liquid-vapor equilibrium. Then the simulation for cycle perforance based on GAX absorption cycle was made using the efficiency of rectifier that established the ammonia concentration in refrigerant and it was derived that 3 [%] decrease of ammonia concentration in refrigerant induced 15 [%] decrcase of cooling COP and 7 [%] decrease of heating COP and that there existed the most suitable circulation ratio for each ammonia concentration in refrigerant.

8. Localization of 3H-diethylstilbestrol in skeletal muscle

SciTech Connect

Gruber, B.; Cohen, L.

1981-11-01

The localization of diethylstilbestrol (DES) in skeletal muscle was studied in CF1 mice and perfused rat hindlimbs. There was a slow accumulation of 3H-DES in mouse muscle from 4 to 24 hours following i.p. injection even though plasma DES was decreasing. Twenty-four hours after injection of 50 microCi 3H-DES (714 pmole) mouse gastrocnemius contained 8.9 x 10(-17) mole unaltered 3H-DES per mg muscle. Extrapolating to the entire skeletal muscle mass of the animal, this represents 0.15% of the radioactivity injected. The radioactivity in muscle was completely extracted with 95% ethanol or ether: ethanol (3:1), and both unaltered DES and DES-metabolites were present in the extracts. The fraction of radioactivity due to unaltered DES 4 hours after injection was 0.51 +/- 0.09 in muscle and 0.30 +/- 0.11 in plasma. Significant extrahepatic metabolism of DES was demonstrated in perfused isolated rat hindlimbs by the presence of DES-metabolites in the perfusate. The radioactivity extracted from the perfused muscle itself was unaltered DES. These results indicate that skeletal muscle is an important site of DES localization in rodents.

9. 1-Phenyl-1H- and 2-phenyl-2H-1,2,3-triazol derivatives: design, synthesis and inhibitory effect on alpha-glycosidases.

PubMed

Gonzaga, Daniel; Senger, Mario Roberto; da Silva, Fernando de Carvalho; Ferreira, Vitor Francisco; Silva, Floriano Paes

2014-03-03

Due to aging and increasingly overweight in human population, the incidence of non-insulin dependent diabetes mellitus (NIDDM or Type 2 DM) is increasing considerably. Therefore, searching for new α-glycosidase inhibitors (GIs) capable of slowing down carbohydrate assimilation by humans is an important strategy towards control of NIDDM. In this report, we disclose the search for new easily accessible synthetic triazoles as anti-diabetic compounds. Two series of non-glycosid triazoles were synthesized (series A and B) and screened against baker's yeast α-glucosidase (MAL12) and porcine pancreatic α-amylase activity (PPA). Of the 60 compounds tested at 500 μM, were considered hits (≥60% inhibition) six triazoles against MAL12 and three against PPA, with the inhibition reaching up to 99.4% on MAL12 and 88.6% on PPA. The IC₅₀ values were calculated for both enzymes and ranged from 54 to 482 μM for MAL12 and 145 to 282 μM for PPA. These results demonstrated the potential activity of simple and non-glycosidic triazoles as an important novel class of GIs for the development of drugs to treat Type 2 DM.

10. Identification and correction of spectral contamination in 2H/1H and 18O/16O measured in leaf, stem, and soil water

Technology Transfer Automated Retrieval System (TEKTRAN)

Plant water extracts typically contain organic materials that may cause spectral interference using isotope ratio infrared spectroscopy (IRIS), resulting in errors in the measured isotope ratios. IRIS manufacturers have developed post-processing software to identify the degree of contamination in wa...

11. THE ABUNDANCE OF C{sub 3}H{sub 2} AND OTHER SMALL HYDROCARBONS IN THE DIFFUSE INTERSTELLAR MEDIUM

SciTech Connect

Liszt, Harvey; Sonnentrucker, Paule; Cordiner, Martin; Gerin, Maryvonne

2012-07-10

Hydrocarbons are ubiquitous in the interstellar medium, observed in diverse environments ranging from diffuse to molecular dark clouds and strong photon-dominated regions near H II regions. Recently, two broad diffuse interstellar bands (DIBs) at 4881 A and 5450 A were attributed to the linear version of propynylidene l-C{sub 3}H{sub 2}, a species whose more stable cyclic conformer c-C{sub 3}H{sub 2} has been widely observed in the diffuse interstellar medium at radio wavelengths. This attribution has already been criticized on the basis of indirect plausibility arguments because the required column densities are quite large, N(l-C{sub 3}H{sub 2})/E{sub B-V} =4 Multiplication-Sign 10{sup 14} cm{sup -2} mag{sup -1}. Here we present new measurements of N(l-C{sub 3}H{sub 2}) based on simultaneous 18-21 GHz Very Large Array absorption profiles of cyclic and linear C{sub 3}H{sub 2} taken along sight lines toward extragalactic radio-continuum background sources with foreground Galactic reddening E{sub B-V} = 0.1-1.6 mag. We find that N(l-C{sub 3}H{sub 2})/N(c-C{sub 3}H{sub 2}) Almost-Equal-To 1/15-1/40 and N(l-C{sub 3}H{sub 2})/E{sub B-V} Almost-Equal-To (2 {+-} 1) Multiplication-Sign 10{sup 11} cm{sup -2} mag{sup -1}, so that the column densities of l-C{sub 3}H{sub 2} needed to explain the DIBs are some three orders of magnitude higher than what is observed. We also find N(C{sub 4}H)/E{sub B-V} <1.3 Multiplication-Sign 10{sup 13} cm{sup -2} mag{sup -1} and N(C{sub 4}H{sup -})/E{sub B-V} <1 Multiplication-Sign 10{sup 11} cm{sup -2} mag{sup -1} (3{sigma}). Using available data for CH and C{sub 2}H we compare the abundances of small hydrocarbons in diffuse and dark clouds as a guide to their ability to contribute as DIB carriers over a wide range of conditions in the interstellar medium.

12. Distribution of 3H-8-MOP and its metabolites in rat organs after a single oral administration

SciTech Connect

Wulf, H.C.; Andreasen, M.P.

1981-04-01

Concentrations of 3H-8-methoxypsoralen (MOP), its lipid- and water soluble metabolites and tritiated water have been measured in rat serum, liver, kidney, and skin, using liquid scintillation, thin-layer chromatography and other techniques. Radioactivity in whole blood, plasma, ovary, adrenals, and pancreas has also been measured. The radioactivty has been measured up to 1 week after medication, while 3H-8-MOP and metabolite concentrations have been measured from 10 min to 24 h after medication with a single dose of 1 mg 3H-8-MOP in solution/kg bodyweight. Maximum 8-MOP concentrations were seen from 10 to 30 min after dosing. The concentrations in microgram/kg 10 min, 2 h, and 24 h after medication were as follows: serum--686, 57, 2.1; liver--489, 45, 3.3; kidney--1708, 139, 4.3; and skin--55, 16, 3.8. The concentrations of water soluble metabolites were very high in the liver and only slightly lower in the kidney. The concentrations of these metabolites might accumulate after doses repeated 4 times a week. 3H-8-MOP and its metabolites would not show similar accumulation. Most of the radioactivity present after 1 week is due to trititated water.

13. Synthesis Of [2h, 13c]M [2h2m 13c], And [2h3,, 13c] Methyl Aryl Sulfones And Sulfoxides

DOEpatents

Martinez, Rodolfo A.; Alvarez, Marc A.; Silks, III, Louis A.; Unkefer, Clifford J.; Schmidt, Jurgen G.

2004-07-20

The present invention is directed to labeled compounds, [.sup.2 H.sub.1, .sup.13 C], [.sup.2 H.sub.2, .sup.13 C] and [.sup.2 H.sub.3, .sup.13 C]methyl aryl sulfones and [.sup.2 H.sub.1, .sup.13 C], [.sup.2 H.sub.2, .sup.13 C] and [.sup.2 H.sub.3, .sup.13 C]methyl aryl sulfoxides, wherein the .sup.13 C methyl group attached to the sulfur of the sulfone or sulfoxide includes exactly one, two or three deuterium atoms and the aryl group is selected from the group consisting of 1-naphthyl, substituted 1-naphthyl, 2-naphthyl, substituted 2-naphthyl, and phenyl groups with the structure: ##STR1## wherein R.sub.1, R.sub.2, R.sub.3, R.sub.4 and R.sub.5 are each independently, hydrogen, a C.sub.1 -C.sub.4 lower alkyl, a halogen, an amino group from the group consisting of NH.sub.2, NHR and NRR' where R and R' are each a C.sub.1 -C.sub.4 lower alkyl, a phenyl, or an alkoxy group. The present invention is also directed to processes of preparing methyl aryl sulfones and methyl aryl sulfoxides.

14. Neurons in the brain of the male cynomolgus monkey accumulate /sup 3/H-medroxyprogesterone acetate (MPA)

SciTech Connect

Michael, R.P.; Bonsall, R.W.; Rees, H.D.

1986-03-01

MPA is a synthetic progestin with androgen-depleting activity. It is used clinically to reduce sexual motivation and aggression in male sex offenders. The mechanisms for its behavioral effects are not known. The authors used steroid autoradiography to help identify sites where MPA may act in the brain of male primates. Twenty-four hours after castration, two adult male cynomolgus macaques, weighing 4.9 and 6.6 kg, were administered 5 mCi /sup 3/H-MPA (NEN, 47.7 Ci/mmol) i.v., and were killed 1 h later. Left sides of the brains and samples of pituitary glands were frozen and 4-micron sections were cut and processed for thaw-mount autoradiography. Radioactivity was concentrated in the nuclei of many neutrons in the ventromedial hypothalamic nucleus (n.), arcuate n., medial preoptic n., and anterior hypothalamic area. Virtually no labeled cells were seen in the bed n. of stria terminalis, lateral septal n., amygdala, or pituitary gland. Right sides of the brains were analyzed by HPLC which demonstrated that 98% of the radioactivity in cell nuclei from the hypothalamus was in the form of unmetabolized /sup 3/H-MPA. The distribution of labelling in the brain following /sup 3/H-MPA administration resembled that previously seen following /sup 3/H-ORG 2058 in female cynomolgus monkeys. These data indicate that MPA has a circumscribed localization in the brain.

15. Design and synthesis of some new quinazolin-4-(3H)-ones as anticonvulsant and antidepressant agents.

PubMed

Amir, Mohd; Ali, Israr; Hassan, Mohd Zaheen

2013-01-01

A series of 3-[(4-substituted-benzylidene)-amino]-2-phenyl-3H-quinazolin-4-ones (5a-k) were synthesized by reacting 3-amino-2-phenyl-1H-quinazolin-4-one with p-hydroxybenzaldehyde, and then further with various alkyl/benzyl halides or substituted phenacyl bromides. The structures of the compounds were confirmed on the basis of IR, NMR, MS and elemental analysis. Anticonvulsant activities were evaluated using the MES and scPTZ tests. Some of the selected compounds were evaluated for antidepressant activity by forced swim pool test. Compound 3-[(4-butoxy-benzylidene)-amino]-2-phenyl-3H-quinazolin-4-one was emerged as the most promising anticonvulsant agent without any motor impairment effect. The whole brain GABA estimation of brain homogenate indicated that the anticonvulsant activity of above mentioned quinazolinone derivatives might be due to an increased GABA concentration.

16. Rate Constant and RRKM Product Study for the Reaction Between CH3 and C2H3 at T = 298K

NASA Technical Reports Server (NTRS)

Thorn, R. Peyton, Jr.; Payne, Walter A., Jr.; Chillier, Xavier D. F.; Stief, Louis J.; Nesbitt, Fred L.; Tardy, D. C.

2000-01-01

The total rate constant k1 has been determined at P = 1 Torr nominal pressure (He) and at T = 298 K for the vinyl-methyl cross-radical reaction CH3 + C2H3 yields products. The measurements were performed in a discharge flow system coupled with collision-free sampling to a mass spectrometer operated at low electron energies. Vinyl and methyl radicals were generated by the reactions of F with C2H4 and CH4, respectively. The kinetic studies were performed by monitoring the decay of C2H3 with methyl in excess, 6 < |CH3|(sub 0)/|C2H3|(sub 0) < 21. The overall rate coefficient was determined to be k1(298 K) = (1.02 +/- 0.53)x10(exp -10) cubic cm/molecule/s with the quoted uncertainty representing total errors. Numerical modeling was required to correct for secondary vinyl consumption by reactions such as C2H3 + H and C2H3 + C2H3. The present result for k1 at T = 298 K is compared to two previous studies at high pressure (100-300 Torr He) and to a very recent study at low pressure (0.9-3.7 Torr He). Comparison is also made with the rate constant for the similar reaction CH3 + C2H5 and with a value for k1 estimated by the geometric mean rule employing values for k(CH3 + CH3) and k(C2H3 + C2H3). Qualitative product studies at T = 298 K and 200 K indicated formation of C3H6, C2H2, and C2H5 as products of the combination-stabilization, disproportionation, and combination-decomposition channels, respectively, of the CH3 + C2H3 reaction. We also observed the secondary C4H8 product of the subsequent reaction of C3H5 with excess CH3; this observation provides convincing evidence for the combination-decomposition channel yielding C3H5 + H. RRKM calculations with helium as the deactivator support the present and very recent experimental observations that allylic C-H bond rupture is an important path in the combination reaction. The pressure and temperature dependencies of the branching fractions are also predicted.

17. Temporal pattern of incorporation of /sup 3/H precursors into pituitary glycoproteins and their subsequent release

SciTech Connect

Grotjan, H.E. Jr.

1982-04-01

The temporal pattern of incorporation of various /sup 3/H precursors into glycoproteins by rat anterior pituitaries incubated in vitro and the release of /sup 3/H-glycoproteins was examined. (/sup 3/H)Leucine incorporation was linear with respect to time and (/sup 3/H)leucine-containing macromolecules appeared in the media in about 1 hr. The temporal pattern of (/sup 3/H)mannose incorporation and release was similar. (/sup 3/H)Galactose and (/sup 3/H)fucose were incorporated after apparent time of delays of approximately 15 min and soon thereafter (20-25 min) appeared in the medium in /sup 3/H-glycoproteins. Thus, these precursors appear to be added as terminal residues. (/sup 3/H)Glucosamine exhibited a pattern intermediate between (/sup 3/H)leucine and (/sup 3/H)fucose whereas (/sup 3/H)GlcNAc appeared to be incorporated as a terminal residue.

18. Teaching 1H NMR Spectrometry Using Computer Modeling.

ERIC Educational Resources Information Center

2001-01-01

Molecular modeling by computer is used to display stereochemistry, molecular orbitals, structure of transition states, and progress of reactions. Describes new ideas for teaching 1H NMR spectroscopy using computer modeling. (Contains 12 references.) (ASK)

19. In vivo binding of (/sup 3/H)Ro 15-1788 in mice: comparison with the in vivo binding of (/sup 3/H)flunitrazepam

SciTech Connect

Potier, M.C.; de Carvalho, L.P.; Dodd, R.H.; Brown, C.L.; Rossier, J.

1988-01-01

Benzodiazepine binding sites have generally been labelled with benzodiazepine agonists: (/sup 3/H)flunitrazepam and (/sup 3/H)diazepam in vivo. The authors studied the in vivo binding of the antagonist (/sup 3/H)Ro 15-1788 in mice and compared it to the in vivo binding of (/sup 3/H)flunitrazepam. For this in vivo labelling, mice were injected with labelled and unlabelled ligands. Animals were then sacrificed and bound radioactivity was measured after homogenization of the excised brain and filtration of the homogenate. (/sup 3/H)Ro 15-1788 is a better tool than (/sup 3/H)flunitrazepam for in vivo labelling of benzodiazepine receptors since 1) it labels specifically the central type binding sites, 2) injection of 4 times less (/sup 3/H)Ro 15-1788 than (/sup 3/H)flunitrazepam produced the same amount of bound radioactivity, 3) 70-90% of the total (/sup 3/H)Ro 15-1788 present in the brain is membrane bound instead of 45-55% with (/sup 3/H)flunitrazepam, 4) maximal binding of (/sup 3/H)Ro 15-1788 is reached within 3 min, 5) only 5% of the membrane bound (/sup 3/H)Ro 15-1788 is nonspecific instead of 15% for (/sup 3/H)flunitrazepam.

20. Effective theory of 3H and 3He

König, Sebastian; Grießhammer, Harald W.; Hammer, H.-W.; van Kolck, U.

2016-06-01

We present a new perturbative expansion for pionless effective field theory with Coulomb interactions in which at leading order (LO) the spin-singlet nucleon-nucleon channels are taken in the unitarity limit. Presenting results up to next-to-leading order for the Phillips line and the neutron-deuteron doublet-channel phase shift, we find that a perturbative expansion in the inverse {}1{S}0 scattering lengths converges rapidly. Using a new systematic treatment of the proton-proton sector that isolates the divergence due to one-photon exchange, we renormalize the corresponding contribution to the {}3{{H}} -{}3{He} binding energy splitting and demonstrate that the Coulomb force in pionless EFT is a completely perturbative effect in the trinucleon bound-state regime. In our new expansion, the LO is exactly isospin-symmetric. At next-to-leading order, we include isospin breaking via the Coulomb force and two-body scattering lengths, and find for the energy splitting {({E}B{(}3{He})-{E}B{(}3{{H}}))}{NLO}\\quad =(-0.86+/- 0.17)\\quad {MeV}.

1. Toxicokinetics of ( sup 3 H)microcystin-LR in mice

SciTech Connect

Robinson, N.A.; Matson, C.F.; Miura, G.A.; Lynch, T.G.; Pace, J.G. )

1990-02-26

Toxicokinetics of ({sup 3}H)microcystin-LR, an algal hepatotoxin, was measured in CD-1 mice (iv, 35 {mu}g/kg, sublethal). The distribution and biological half-lives in plasma were 0.8 and 7 minutes, respectively. Liver rapidly accumulated toxin; uptake half-life was 7 minutes. After 60 minutes, liver, kidney, intestine and carcass retained 67{+-}4, 0.8{+-}0.1, 8.6{+-}0.7 and 6{+-}2% of dose, respectively. By 8 days, 18{+-}1 and 7.6{+-}0.6% of the administered radiolabel appeared in feces and urine, while liver and carcass retained 50{+-}2 and 8{+-}3%, respectively. In urine (6 and 12 hours) and feces (6, 12 and 24 hours) {approximately}60% of the tritium was associated with the parent compound. Hepatic radiolabel was tightly bound to cytosolic protein(s). One hour after injection, 27{+-}3% of the hepatic radiolabel was parent compound and 73{+-}3% was a more-polar component (peak 1). By 8 days, there was a redistribution of hepatic radioactivity: 69{+-}2% with a parent and 4{+-}0.5% with peak 1. The authors conclude that ({sup 3}H)MCYST rapidly accumulated in liver, was metabolized and was associated with cytosolic protein.

2. Tissue distribution of 3H-terbutaline in rabbits.

PubMed

Hsu, C H; Robinson, C P; Basmadjian, G P

1994-01-01

Terbutaline is a widely used, selective beta 2-adrenergic agonist whose penetration into brain has not been demonstrated in laboratory animals. Although its tissue uptake has been reported in some animals, no uptake into brain has been demonstrated. A single dose of 20 microCi of 3H-terbutaline along with 10 mg/kg of unlabeled terbutaline was injected into a rabbit marginal ear vein. The distribution of 3H-terbutaline in several tissues was determined 0.5, 1, 3, or 6 hr later. Radioactivity in the brain was well-maintained over the 6 hr observation period. In most tissues, radioactivity peaked in less than 1 hr, then declined. Radioactivity in the urine was high at all time periods and was highest at 3 hr. Thus, terbutaline or a metabolite(s) does cross the blood-brain barrier in rabbits, and the radioactivity in the rabbit brain does not decrease during the 6 hours following terbutaline injection.

3. A Search for Interstellar Oxiranecarbonitrile (C3H3NO)

NASA Technical Reports Server (NTRS)

Dicken, J. E.; Irvine, W. M.; Ohishi, M.; Arrhenius, G.; Bauder, A.; Mueller, F.; Eschenmoser, A.

1996-01-01

We report a search in cold, quiescent and in 'hot core' type interstellar molecular clouds for the small cyclic molecule oxiranecarbonitrile (C3H3NO), which has been suggested as a precursor of important prebiotic molecules. We have determined upper limits to the column density and fractional abundance for the observed sources and find that, typically, the fractional abundance by number relative to molecular hydrogen Of C3H3NO is less than a few times 10(exp -10). This limit is one to two orders of magnitude less than the measured abundance of such similarly complex species as CH3CH2CN and HCOOCH3 in well-studied hot cores. A number of astrochemical discoveries were made, including the first detection of the species CH3CH2CN in the massive star-forming clouds G34.3+0.2 and W51M and the first astronomical detections of some eight rotational transitions of CH3CH2CN, CH3CCH, and HCOOCH3. In addition, we found 8 emission lines in the 89 GHz region and 18 in the 102 GHz region which we were unable to assign.

4. The 3H-3He Charge Radii Difference

SciTech Connect

Myers, Luke S.; Arrington, John R.; Higinbotham, Douglas W.

2016-03-01

The upcoming E12-14-009 [1] experiment at Jefferson Lab will determine the ratio of the electric form factors for the A=3 mirror nuclei 3He and 3H. The measurement will use a 1.1 GeV electron beam, a special collimator plate to allow for simultaneous optics measurements, and the low-activity tritium target being prepared for Jefferson Lab. By observing the dependence of the form factor ratio as a function of Q2 over 0.05–0.09 GeV2, the dependence of the radii extraction on the shape of the form factors is minimized. As a result, we anticipate the uncertainty of the extracted charge radii difference to be 0.03 fm, a reduction of 70% from the current measurement. Using precise measurements of the 3He charge radius from isotopic shift or μHe measurements [2–4], we can deduce the absolute 3H charge radius. The results will provide a direct comparison to recent calculations of the charge radii.

5. Beryllium-induced immune response in C3H mice

SciTech Connect

Benson, J.M.; Bice, D.E.; Nikula, K.J.

1995-12-01

Studies conducted at ITRI over the past several years have investigated whether Beagle dogs, monkeys, and mice are suitable models for human chronic beryllium-induced lung disease (CBD). Recent studies have focused on the histopathological and immunopathological changes occurring in A/J and C3H/HeJ mice acutely exposed by inhalation to Be metal. Lung lesions in both strains of mice included focal lymphocyte aggregates comprised primarily of B lymphocytes and lesser amounts of T-helper lymphocytes and microgranulomas consisting chiefly of macrophages and T-helper lymphocytes. The distribution of proliferating cells within the microgranulomas was similar to the distribution of T-helper cells. These results strongly suggested that A/J and C3H/HeJ mice responded to inhaled Be metal in a fashion similar to humans in terms of pulmonary lesions and the apparent in situ proliferation of T-helper cells. Results of these studies confirm lymphocyte involvement in the pulmonary response to inhaled Be metal.

6. Synthesis and properties of 3-nitro-2H-chromenes

Korotaev, V. Yu; Sosnovskikh, V. Ya; Barkov, A. Yu

2013-12-01

Methods of synthesis and chemical properties of 3-nitro-2H-chromenes, including reactions with nucleophiles, cycloaddition, oxidation and reduction, have been reviewed. Enantioselective reactions involving 3-nitro-2H-chromenes, as well as the stereochemistry of the products, are discussed. The ways of practical use of these compounds are shown. The bibliography includes 115 references.

7. Free radical scavenging potency of quercetin catecholic colonic metabolites: Thermodynamics of 2H(+)/2e(-) processes.

PubMed

Amić, Ana; Lučić, Bono; Stepanić, Višnja; Marković, Zoran; Marković, Svetlana; Dimitrić Marković, Jasmina M; Amić, Dragan

2017-03-01

Reaction energetics of the double (2H(+)/2e(-)), i.e., the first 1H(+)/1e(-) (catechol→ phenoxyl radical) and the second 1H(+)/1e(-) (phenoxyl radical→ quinone) free radical scavenging mechanisms of quercetin and its six colonic catecholic metabolites (caffeic acid, hydrocaffeic acid, homoprotocatechuic acid, protocatechuic acid, 4-methylcatechol, and catechol) were computationally studied using density functional theory, with the aim to estimate the antiradical potency of these molecules. We found that second hydrogen atom transfer (HAT) and second sequential proton loss electron transfer (SPLET) mechanisms are less energy demanding than the first ones indicating 2H(+)/2e(-) processes as inherent to catechol moiety. The Gibbs free energy change for reactions of inactivation of selected free radicals indicate that catecholic colonic metabolites constitute an efficient group of more potent scavengers than quercetin itself, able to deactivate various free radicals, under different biological conditions. They could be responsible for the health benefits associated with regular intake of flavonoid-rich diet.

8. Variations of δ2H in an idealised extratropical cyclone

Dütsch, Marina; Pfahl, Stephan; Wernli, Heini

2016-04-01

Numerical model simulations of stable water isotopes help to improve our understanding of the complex processes driving isotopic variability in atmospheric waters. We use the isotope-enabled COSMO model to study the governing mechanisms of δ2H variations in an idealised extratropical cyclone. A set of experiments with differing initial conditions of δ2H in vapour and partially deactivated isotopic fractionation allows us to quantify the relative roles of cloud fractionation and vertical and horizontal advection for the simulated δ2H signals associated with the cyclone and fronts. Horizontal transport determines the large-scale pattern of δ2H in both vapour and precipitation, while fractionation and vertical transport are more important on a smaller scale, near the fronts. During the passage of the cold front fractionation leads to a V-shaped trend of δ2H in precipitation and vapour, which is, for vapour, superimposed on a gradual decrease caused by horizontal advection.

9. Bindings of /sup 3/H-prazosin and /sup 3/H-yohimbine to alpha adrenoceptors in the guinea-pig stomach

SciTech Connect

Taniguchi, T.; Nishikawa, H.

1988-01-01

Alpha adrenoceptor subtypes have been investigated by radioligand binding study in guinea-pig stomach using /sup 3/H-prazosin and /sup 3/H-yohimbine. The specific /sup 3/H-prazosin binding to guinea-pig stomach was saturable and of high affinity with a Bmax of 33 fmol/mg protein. Specific /sup 3/H-yohimbine binding to the tissue was also saturable and of high affinity with a Bmax of 150 fmol/mg protein. Adrenergic drugs competed for /sup 3/H-prazosin binding in order of prazosin > phentolamine > methoxamine > norepinephrine > clonidine > epinephrine > yohimbine. These drugs competed for /sup 3/H-yohimbine binding in order of yohimbine > phentolamine > clonidine > epinephrine > norepinephrine > prazosin > methoxamine. They also examined whether dopamine receptors exist in guinea-pig stomach, using radioligand binding study. Specific binding of /sup 3/H-spiperone, /sup 3/H-apomorphine, /sup 3/H-dopamine and /sup 3/H-domperidone was not detectable in the stomach. Dopaminergic drugs such as dopamine, haloperidol, domperidone and sulpiride competed for /sup 3/H-prazosin binding in order of haloperidol > domperidone > dopamine > sulpiride. Metoclopramide, sulpiride and dopamine competed for /sup 3/H-yohimbine binding in order of metoclopramide > sulpiride > dopamine.

10. Quasifree Lambda, Sigma^0, and Sigma^- electroproduction from 1,2H, 3,4He, and Carbon

SciTech Connect

F. Dohrmann; A. Ahmidouch; C.S. Armstrong; J. Arrington; R. Asaturyan; S. Avery; K. Bailey; H. Bitao; H. Breuer; D.S. Brown; R. Carlini; J. Cha; N. Chant; E. Christy; A. Cochran; L. Cole; J. Crowder; S. Danagoulian; M. Elaasar; R. Ent; H. Fenker; Y. Fujii; L. Gan; K. Garrow; D.F. Geesaman; P. Gueye; K. Hafidi; W. Hinton; H. Juengst; C. Keppel; Y. Liang; J.H. Liu; A. Lung; D. Mack; P. Markowitz; J. Mitchell; T. Miyoshi; H. Mkrtchyan; S.K. Mtingwa; B. Mueller; G. Niculescu; I. Niculescu; D. Potterveld; B.A. Raue; P.E. Reimer; J. Reinhold; J. Roche; M. Sarsour; Y. Sato; R.E. Segel; A. Semenov; S. Stepanyan; V. Tadevosyan; S. Tajima; L. Tang; A. Uzzle; S. Wood; H. Yamaguchi; C. Yan; L. Yuan; B. Zeidman; M. Zeier; B. Zihlmann

2007-07-30

Kaon electroproduction from light nuclei and hydrogen, using 1H, 2H, 3He, 4He, and Carbon targets has been measured at Jefferson Laboratory. The quasifree angular distributions of Lambda and Sigma hyperons were determined at Q^2= 0.35(GeV/c)^2 and W= 1.91GeV. Electroproduction on hydrogen was measured at the same kinematics for reference.

11. Syntheses, structures, and 1H, 13C{1H} and 119Sn{1H} NMR chemical shifts of a family of trimethyltin alkoxide, amide, halide and cyclopentadienyl compounds

DOE PAGES

Lichtscheidl, Alejandro G.; Janicke, Michael T.; Scott, Brian L.; ...

2015-08-21

The synthesis and full characterization, including Nuclear Magnetic Resonance (NMR) data (1H, 13C{1H} and 119Sn{1H}), for a series of Me3SnX (X = O-2,6-tBu2C6H3 (1), (Me3Sn)N(2,6-iPr2C6H3) (3), NH-2,4,6-tBu3C6H2 (4), N(SiMe3)2 (5), NEt2, C5Me5 (6), Cl, Br, I, and SnMe3) compounds in benzene-d6, toluene-d8, dichloromethane-d2, chloroform-d1, acetonitrile-d3, and tetrahydrofuran-d8 are reported. The X-ray crystal structures of Me3Sn(O-2,6-tBu2C6H3) (1), Me3Sn(O-2,6-iPr2C6H3) (2), and (Me3Sn)(NH-2,4,6-tBu3C6H2) (4) are also presented. As a result, these compiled data complement existing literature data and ease the characterization of these compounds by routine NMR experiments.

12. The Phaseolus vulgaris PvTRX1h gene regulates plant hormone biosynthesis in embryogenic callus from common bean.

PubMed

Barraza, Aarón; Cabrera-Ponce, José L; Gamboa-Becerra, Roberto; Luna-Martínez, Francisco; Winkler, Robert; Álvarez-Venegas, Raúl

2015-01-01

Common bean is the most important grain legume in the human diet. Bean improvement efforts have been focused on classical breeding techniques because bean is recalcitrant to both somatic embryogenesis and in vitro regeneration. This study was undertaken to better understand the process of somatic embryogenesis in the common bean. We focused on the mechanisms by which somatic embryogenesis in plants is regulated and the interaction of these mechanisms with plant hormones. Specifically, we examined the role of the gene PvTRX1h, an ortholog of a major known histone lysine methyltransferase in plants, in somatic embryo generation. Given the problems with regeneration and transformation, we chose to develop and use regeneration-competent callus that could be successively transformed. Embryogenic calli of common bean were generated and transformed with the PvTRX1hRiA construction to down-regulate, by RNA interference, expression of the PvTRX1h gene. Plant hormone content was measured by mass spectrometry and gene expression was assessed by q-PCR. Detailed histological analysis was performed on selected transgenic embryogenic calli. It was determined that down-regulation of PvTRX1h gene was accompanied by altered concentrations of plant hormones in the calli. PvTRX1h regulated the expression of genes involved in auxin biosynthesis and embryogenic calli in which PvTRX1h was down-regulated were capable of differentiation into somatic embryos. Also, down-regulation of PvTRX1h showed increased transcript abundance of a gene coding for a second histone lysine methyltransferase, PvASHH2h. Accordingly, the PvTRX1h gene is involved in the synthesis of plant hormones in common bean callus. These results shed light on the crosstalk among histone methyltransferases and plant hormone signaling and on gene regulation during somatic embryo generation.

13. The Phaseolus vulgaris PvTRX1h gene regulates plant hormone biosynthesis in embryogenic callus from common bean

PubMed Central

Barraza, Aarón; Cabrera-Ponce, José L.; Gamboa-Becerra, Roberto; Luna-Martínez, Francisco; Winkler, Robert; Álvarez-Venegas, Raúl

2015-01-01

Common bean is the most important grain legume in the human diet. Bean improvement efforts have been focused on classical breeding techniques because bean is recalcitrant to both somatic embryogenesis and in vitro regeneration. This study was undertaken to better understand the process of somatic embryogenesis in the common bean. We focused on the mechanisms by which somatic embryogenesis in plants is regulated and the interaction of these mechanisms with plant hormones. Specifically, we examined the role of the gene PvTRX1h, an ortholog of a major known histone lysine methyltransferase in plants, in somatic embryo generation. Given the problems with regeneration and transformation, we chose to develop and use regeneration-competent callus that could be successively transformed. Embryogenic calli of common bean were generated and transformed with the PvTRX1hRiA construction to down-regulate, by RNA interference, expression of the PvTRX1h gene. Plant hormone content was measured by mass spectrometry and gene expression was assessed by q-PCR. Detailed histological analysis was performed on selected transgenic embryogenic calli. It was determined that down-regulation of PvTRX1h gene was accompanied by altered concentrations of plant hormones in the calli. PvTRX1h regulated the expression of genes involved in auxin biosynthesis and embryogenic calli in which PvTRX1h was down-regulated were capable of differentiation into somatic embryos. Also, down-regulation of PvTRX1h showed increased transcript abundance of a gene coding for a second histone lysine methyltransferase, PvASHH2h. Accordingly, the PvTRX1h gene is involved in the synthesis of plant hormones in common bean callus. These results shed light on the crosstalk among histone methyltransferases and plant hormone signaling and on gene regulation during somatic embryo generation. PMID:26284093

14. Comparison of (/sup 3/H)pirenzepine and (/sup 3/H)quinuclidinylbenzilate binding to muscarinic cholinergic receptors in rat brain

SciTech Connect

Luthin, G.R.; Wolfe, B.B.

1984-03-01

The properties of (/sup 3/H)quinuclidinylbenzilate ( (/sup 3/H)QNB) binding and (/sup 3/H)pirenzepine ( (/sup 3/H)PZ) binding to various regions of rat brain were compared. (/sup 3/H)PZ appeared to bind with high affinity to a single site, with a Kd value of approximately 15 nM in the cerebral cortex. The rank order of potencies of muscarinic drugs to inhibit binding of either (/sup 3/H)QNB or (/sup 3/H)PZ was QNB greater than atropine . scopolamine greater than pirenzepine greater than oxotremorine greater than bethanechol. Muscarinic antagonists (except PZ) inhibited both (/sup 3/H)PZ and (/sup 3/H)QNB binding with Hill coefficients of approximately 1. PZ inhibited (/sup 3/H)QNB binding in cortex with a Hill coefficient of 0.7, but inhibited (/sup 3/H)PZ binding with a Hill coefficient of 1.0. Hill coefficients for agonists were less than 1. The density of (/sup 3/H)PZ binding sites was approximately half the density of (/sup 3/H)QNB binding sites in cortex, striatum and hippocampus. In pons-medulla and cerebellum, the densities of (/sup 3/H)PZ binding sites were 20 and 0%, respectively, relative to the densities of (/sup 3/H)QNB binding sites. When unlabeled PZ was used to compete for (/sup 3/H)QNB binding, the relative number of high-affinity PZ binding sites in cortex, pons and cerebellum agreed with the relative number of (/sup 3/H)PZ binding sites in those regions. The binding of (/sup 3/H)PZ and (/sup 3/H)QNB was nonadditive in cortex. GTP inhibited high-affinity oxotremorine binding, but not PZ binding. Together, these data suggest that (/sup 3/H)PZ binds to a subset of (/sup 3/H)QNB binding sites. Whether this subset reflects the existence of subtypes of muscarinic receptors or is a consequence of coupling to another membrane protein remains to be seen.

15. The tissue-specific distribution of 3H-seocalcitol (EB 1089) and 3H-calcitriol in rats.

PubMed

Kissmeyer, Anne-Marie; Nielsen, Jeanet Løgsted; Binderup, Lise

2004-05-01

Seocalcitol (EB 1089) is under development for the treatment of hepato-cellular carcinoma (HCC). The tissue distribution of 3H-seocalcitol was investigated in comparison to 3H-calcitriol in rats. Quantitative whole-body autoradiography was used to quantify the tissue distribution. The greatest difference in distribution between the two compounds was observed in the bloodstream. For most tissues the ratio seocalcitol/calcitriol varied between 0.2 and 3.1. The concentration of radioactivity in the liver was almost the same for the two compounds. For seocalcitol the concentration in the liver was 10 times higher than in serum. Assuming that the liver/serum concentration ratio is the same in rats and humans, the concentration of seocalcitol in the human liver is expected to be higher than the concentration resulting in more than 50% inhibition of cancer cell proliferation, and thus pharmacologically effective in HCC. It is questionable whether calcitriol would be present in the human liver in sufficient concentrations to be effective for the treatment of HCC, as the antiproliferative activity of calcitriol is generally more than 10-fold lower compared to that of seocalcitol and as calcitriol can only be administered at a dose that is ca. three-fold lower than the dose of seocalcitol.

16. Experimental and calculated 1H, 13C, 15N NMR spectra of famotidine

Barańska, M.; Czarniecki, K.; Proniewicz, L. M.

2001-05-01

Famotidine, 3-[[[2-[(aminoiminomethyl)amino]-4-thiazolyl]methyl]thio]- N-(aminosulfonyl), is a histamine H 2-receptor blocker that has been used mainly for the treatment of peptic ulcers and the Zollinger-Ellison syndrome. Its NMR spectra in different solvents were reported earlier; however, detailed interpretation has not been done thus far. In this work, experimental 1H, 13C and 15N NMR spectra of famotidine dissolved in DMSO-d 6 are shown. The assignment of observed chemical shifts is based on quantum chemical calculation at the Hartree-Fock/6-31G ∗ level. The geometry optimization of the famotidine molecule with two internal hydrogen bonds, i.e. [N(3)-H(23)⋯N(9) and N(3)⋯H(34)-N(20)], is done by using the B3LYP method with the 6-31G ∗ basis set.

17. Measurement of /sup 2/H/sub 2/O by IR absorbance in doubly labeled H/sub 2/O studies of energy expenditure

SciTech Connect

Karasov, W.H.; Han, L.R.; Munger, J.C.

1988-07-01

The energy expenditure of animals in their natural surroundings can be determined by measuring the turnover in body water of isotopes of oxygen and hydrogen. We evaluated the use of infrared spectrophotometry for measuring /sup 2/H/sub 2/O in small (20-microliters) water samples also labeled with 18O. For /sup 2/H/sub 2/O over the enrichment range of 0.1-1 atom%, there was a linear relationship between infrared absorbance and /sup 2/H/sub 2/O enrichment. /sup 2/H/sub 2/O enrichments could be measured with a precision and accuracy of less than or equal to 1%, using this relationship. The presence of /sup 18/O in water samples in enrichments of up to 1 atom% had no significant effect on measurement of /sup 2/H/sub 2/O by infrared absorbance. We measured the simultaneous turnover rates of /sup 2/H/sub 2/O and /sup 3/H in mice and turtles also labeled with 18O. Our results validated the use of infrared absorbance in doubly labeled water measures of energy expenditure and indicated that the fractionation factors in vivo for /sup 2/H/sub 2/O and /sup 3/H do not differ.

18. Human SLC4A11 Is a Novel NH3/H+ Co-transporter*

PubMed Central

Zhang, Wenlin; Ogando, Diego G.; Bonanno, Joseph A.; Obukhov, Alexander G.

2015-01-01

SLC4A11 has been proposed to be an electrogenic membrane transporter, permeable to Na+, H+ (OH−), bicarbonate, borate, and NH4+. Recent studies indicate, however, that neither bicarbonate or borate is a substrate. Here, we examined potential NH4+, Na+, and H+ contributions to electrogenic ion transport through SLC4A11 stably expressed in Na+/H+ exchanger-deficient PS120 fibroblasts. Inward currents observed during exposure to NH4Cl were determined by the [NH3]o, not [NH4+]o, and current amplitudes varied with the [H+] gradient. These currents were relatively unaffected by removal of Na+, K+, or Cl− from the bath but could be reduced by inclusion of NH4Cl in the pipette solution. Bath pH changes alone did not generate significant currents through SLC4A11, except immediately following exposure to NH4Cl. Reversal potential shifts in response to changing [NH3]o and pHo suggested an NH3/H+-coupled transport mode for SLC4A11. Proton flux through SLC4A11 in the absence of ammonia was relatively small, suggesting that ammonia transport is of more physiological relevance. Methylammonia produced currents similar to NH3 but with reduced amplitude. Estimated stoichiometry of SLC4A11 transport was 1:2 (NH3/H+). NH3-dependent currents were insensitive to 10 μm ethyl-isopropyl amiloride or 100 μm 4,4′- diisothiocyanatostilbene-2,2′-disulfonic acid. We propose that SLC4A11 is an NH3/2H+ co-transporter exhibiting unique characteristics. PMID:26018076

19. Ascorbic acid and striatal transport of (/sup 3/H)1-methyl-4-phenylpyridine (MPP/sup +/) and (/sup 3/H)dopamine

SciTech Connect

Debler, E.A.; Hashim, A.; Lajtha, A.; Sershen, H.

1988-01-01

The inhibition of uptake of (/sup 3/H)dopamine and (/sup 3/H)1-methyl-4-phenylpyridine (MPP/sup +/) was examined in mouse striatal synaptosomal preparations. Kinetic analysis indicated that ascorbic acid is a noncompetitive inhibitor of (/sup 3/H)MPP/sup +/ uptake. No inhibition of (/sup 3/H)dopamine uptake is observed. The dopamine uptake blockers, GBR-12909, cocaine, and mazindol strongly inhibit (IC/sub 50/ < 1 ..mu..M) both (/sup 3/H)dopamine and (/sup 3/H)MPP/sup +/ transport. Nicotine, its metabolites, and other tobacco alkaloids are weak inhibitors except 4-phenylpyridine and lobeline, which are moderate inhibitors of both (/sup 3/H)dopamine and (/sup 3/H)MPP/sup +/ uptake. These similarities in potencies are in agreement with the suggestion that (/sup 3/H)MPP/sup +/ and (/sup 3/H) are transported by the same carrier. The differences observed in the alteration of dopaminergic transport and mazindol binding by ascorbic acid suggest that ascorbic acid's effects on (/sup 3/H)MPP/sup +/ transport are related to translocation and/or dissociation processes occurring subsequent to the initial binding event.

20. Clinical and treatment effects on /sup 3/H-clonidine and /sup 3/H-imipramine binding in elderly depressed patients

SciTech Connect

Georgotas, A.; Schweitzer, J.; McCue, R.E.; Armour, M.; Friedhoff, A.J.

1987-06-01

/sup 3/H-clonidine and /sup 3/H-imipramine binding were measured in depressed patients, 55 years and older. There was no significant difference in either /sup 3/H-clonidine or /sup 3/H-imipramine binding between depressed patients and age- and sex-matched controls. There was no significant correlation between /sup 3/H-clonidine or /sup 3/H-imipramine binding and severity of depression before treatment. There was a significant negative correlation between the K/sub D/ of /sup 3/H-imipramine binding sites and Hamilton score over seven weeks of antidepressant treatment. There was no significant difference between receptor data of responders and nonresponders to antidepressant treatment. 19 references, 2 tables.

1. Temperature and pressure dependent rate coefficients for the reaction of C2H4 + HO2 on the C2H4O2H potential energy surface.

PubMed

Guo, JunJiang; Xu, JiaQi; Li, ZeRong; Tan, NingXin; Li, XiangYuan

2015-04-02

The potential energy surface (PES) for reaction C2H4 + HO2 was examined by using the quantum chemical methods. All rates were determined computationally using the CBS-QB3 composite method combined with conventional transition state theory(TST), variational transition-state theory (VTST) and Rice-Ramsberger-Kassel-Marcus/master-equation (RRKM/ME) theory. The geometries optimization and the vibrational frequency analysis of reactants, transition states, and products were performed at the B3LYP/CBSB7 level. The composite CBS-QB3 method was applied for energy calculations. The major product channel of reaction C2H4 + HO2 is the formation C2H4O2H via an OH(···)π complex with 3.7 kcal/mol binding energy which exhibits negative-temperature dependence. We further investigated the reactions related to this complex, which were ignored in previous studies. Thermochemical properties of the species involved in the reactions were determined using the CBS-QB3 method, and enthalpies of formation of species were compared with literature values. The calculated rate constants are in good agreement with those available from literature and given in modified Arrhenius equation form, which are serviceable in combustion modeling of hydrocarbons. Finally, in order to illustrate the effect for low-temperature ignition of our new rate constants, we have implemented them into the existing mechanisms, which can predict ethylene ignition in a shock tube with better performance.

2. 3,4-Methylenedioxyamphetamine (MDA) analogues exhibit differential effects on synaptosomal release of 3H-dopamine and 3H-5-hydroxytryptamine

SciTech Connect

McKenna, D.J.; Guan, X.M.; Shulgin, A.T. )

1991-03-01

The effect of various analogues of the neurotoxic amphetamine derivative, MDA (3,4-methylenedioxyamphetamine) on carrier-mediated, calcium-independent release of 3H-5-HT and 3H-DA from rat brain synaptosomes was investigated. Both enantiomers of the neurotoxic analogues MDA and MDMA (3,4-methylenedioxymethamphetamine) induce synaptosomal release of 3H-5-HT and 3H-DA in vitro. The release of 3H-5-HT induced by MDMA is partially blocked by 10(-6) M fluoxetine. The (+) enantiomers of both MDA and MDMA are more potent than the (-) enantiomers as releasers of both 3H-5-HT and 3H-DA. Eleven analogues, differing from MDA with respect to the nature and number of ring and/or side chain substituents, also show some activity in the release experiments, and are more potent as releasers of 3H-5-HT than of 3H-DA. The amphetamine derivatives {plus minus}fenfluramine, {plus minus}norfenfluramine, {plus minus}MDE, {plus minus}PCA, and d-methamphetamine are all potent releasers of 3H-5-HT and show varying degrees of activity as 3H-DA releasers. The hallucinogen DOM does not cause significant release of either 3H-monoamine. Possible long-term serotonergic neurotoxicity was assessed by quantifying the density of 5-HT uptake sites in rats treated with multiple doses of selected analogues using 3H-paroxetine to label 5-HT uptake sites. In the neurotoxicity study of the compounds investigated, only (+)MDA caused a significant loss of 5-HT uptake sites in comparison to saline-treated controls. These results are discussed in terms of the apparent structure-activity properties affecting 3H-monoamine release and their possible relevance to neurotoxicity in this series of MDA congeners.

3. Selective labeling of serotonin uptake sites in rat brain by (/sup 3/H)citalopram contrasted to labeling of multiple sites by (/sup 3/H)imipramine

SciTech Connect

D'Amato, R.J.; Largent, B.L.; Snowman, A.M.; Snyder, S.H.

1987-07-01

Citalopram is a potent and selective inhibitor of neuronal serotonin uptake. In rat brain membranes (/sup 3/H)citalopram demonstrates saturable and reversible binding with a KD of 0.8 nM and a maximal number of binding sites (Bmax) of 570 fmol/mg of protein. The drug specificity for (/sup 3/H)citalopram binding and synaptosomal serotonin uptake are closely correlated. Inhibition of (/sup 3/H)citalopram binding by both serotonin and imipramine is consistent with a competitive interaction in both equilibrium and kinetic analyses. The autoradiographic pattern of (/sup 3/H)citalopram binding sites closely resembles the distribution of serotonin. By contrast, detailed equilibrium-saturation analysis of (/sup 3/H)imipramine binding reveals two binding components, i.e., high affinity (KD = 9 nM, Bmax = 420 fmol/mg of protein) and low affinity (KD = 553 nM, Bmax = 8560 fmol/mg of protein) sites. Specific (/sup 3/H)imipramine binding, defined as the binding inhibited by 100 microM desipramine, is displaced only partially by serotonin. Various studies reveal that the serotonin-sensitive portion of binding corresponds to the high affinity sites of (/sup 3/H)imipramine binding whereas the serotonin-insensitive binding corresponds to the low affinity sites. Lesioning of serotonin neurons with p-chloroamphetamine causes a large decrease in (/sup 3/H)citalopram and serotonin-sensitive (/sup 3/H)imipramine binding with only a small effect on serotonin-insensitive (/sup 3/H)imipramine binding. The dissociation rate of (/sup 3/H)imipramine or (/sup 3/H)citalopram is not altered by citalopram, imipramine or serotonin up to concentrations of 10 microM. The regional distribution of serotonin sensitive (/sup 3/H)imipramine high affinity binding sites closely resembles that of (/sup 3/H)citalopram binding.

4. Theoretical study of the bonding of Nb(2+) to CH2, C2H2, and C2H4

NASA Technical Reports Server (NTRS)

Bauschlicher, Charles W., Jr.; Langhoff, Stephen R.; Partridge, Harry

1991-01-01

The bonding of Nb(2+) with CH2, C2H2, and C2H4 is studied by using electronic structure calculations that include high levels of electron correlation. The binding energy for NbCH2(2+) is in good agreement with the lower bound determined from the reaction with CH4 but is significantly smaller than the value determined from the binding energy and ionization potential of NbCH2(+). The calculations and a new interpretation of the experiment indicate that the larger value is in error primarily because the ionization potential of NbCH2(+) determined from bracketing charge-exchange reactions is too small. The computed binding energy of NbC2H2(2+) is in good agreement with experiment. The calculations show that the bonding is predominantly covalent in character for both NbCH2(2+) and NbC2H2(2+), whereas for NbC2H4(2+) the electronic states that are predominantly ionic and covalent are nearly degenerate. The trend in binding energies, CH2 greater than C2H2 greater than C2H4, is consistent with the energy required to prepare the ligands for bonding.

5. Efficient C2 functionalisation of 2H-2-imidazolines.

PubMed

Bon, Robin S; Sprenkels, Nanda E; Koningstein, Manoe M; Schmitz, Rob F; de Kanter, Frans J J; Dömling, Alexander; Groen, Marinus B; Orru, Romano V A

2008-01-07

Alkylation and oxidation of 2H-2-imidazolines, followed by regioselective deprotection, thionation and microwave-assisted Liebeskind-Srogl reaction, efficiently led to 2-aryl-2-imidazolines as new analogues of p53-hdm2 interaction inhibitors (Nutlins).

6. Bis(5-amino-3-carb­oxy-1H-1,2,4-triazol-4-ium) dihydrogenphosphate nitrate 5-amino-1H-1,2,4-triazol-4-ium-3-carboxyl­ate

PubMed Central

Berrah, Fadila; Bouchene, Rafika; Bouacida, Sofiane; Daran, Jean-Claude

2012-01-01

In the title compound, 2C3H5N4O2 +·H2PO4 −·NO3 −·C3H4N4O2, three independent 5-amino-1H-1,2,4-triazol-3-carb­oxy­lic acid moieties are observed. Two are in the form of cations, while the third is in the zwitterionic form. The triazole rings in the two cations are almost coplanar, making an angle of 4.11 (7)°. Layers parallel to the (20-1) plane, resulting from hydrogen bonding of the organic mol­ecules and the nitrate anions, are linked via H2PO4 − infinite zigzag chains running parallel to the c axis. The crystal studied was an inversion twin, with refined components of 0.33 (7) and 0.67 (7). PMID:22590233

7. Synthesis and anticonvulsant activity of 5-chloro-2(3H)-benzoxazolinone-3-acetyl-2-(o/p-substituted benzal) hydrazone derivatives.

PubMed

Gökçe, Mehtap; Geciken, Ahmet Emin; Yildirim, Engin; Tosuni, Ali Ulvi

2008-01-01

It is well known that some hydrazone derivatives of both 2-oxobenzoxazoline and 2-oxobenzothiazoline exhibit potent anticonvulsant activity. In order to investigate the effects of structural modifications on the biological properties, 14 new hydrazones of 5-chloro-2(3H)-benzox-azolinone-3-acetyl hydrazide were synthesized. The chemical structures of the synthesized compounds were established by IR, 1H-NMR spectral analyses and elementary analyses. The anticonvulsant activities of the title compounds were tested by the penthylenetetrazole induced seizure test. 5-Chloro-2(3H)-benz-oxazolinone-3-acetyl-2-(o-methoxy-benzaldehyde)-hydrazone 4d, 5-chloro-2(3H)-benzoxazolinone-3-acetyl-2-(o-methybenzaldehyde)-hydrazone 4g, 5-chloro-2(3H)-benzoxazolinone-3-acetyl-2-(p-methylbenzaldehyde)-hydrazone 4h, 5-chloro-2(3H)-benzoxazolino-ne-3-acetyl-2-(p-nitrobenzaldehyde)-hydrazone 4m, and 5-chloro-2(3H)-benzox-azolinone-3-acetyl-2-(p-dimethylaminobenzaldehyde)-hydrazone 4n were found more active than phenytoin (CAS 57-41-0) in the tests.

8. Organic Compounds in the C3H6O3 Family: Microwave Spectrum of cis-cis Dimethyl Carbonate

McGuire, B. A.; Widicus Weaver, S. L.; Lovas, F. J.; Plusquellic, D. F.; Blake, G. A.

2011-05-01

A number of recent spectroscopic and observational efforts have focused on simple sugars and sugar alcohols because of their importance in prebiotic astro- chemistry. The simplest sugar-related species, glycolaldehyde, has been detected in Sgr B2(N), as have its C2H4O2 structural isomers acetic acid and methyl formate. Additional studies of the C3-sugars with empirical formula C3H6O3, glyceraldehyde and dihydroxyacetone, resulted in no clear interstellar detection. Structural isomerism is extensive in interstellar clouds, and there is a high level of correlation between the relative energies of isomers and their relative abundances, with the lowest energy isomers detected in greatest abundance. The detected members of the C2H4O2 family, however, defy this trend, having relative abundances of (acetic acid):(glycolaldehyde):(methyl formate) of about 2:1:52, despite acetic acid being the lowest energy isomer. These puzzling abundance ratios and the lack of detection of the C3H6O3 sugars gives rise to the question: "Which is the most likely isomer in the C3H6O3 family to be detectable in inter- stellar clouds?" In an attempt to answer this question, we carried out geometry optimization calculations to determine the relative binding energies of the 13 members of the C3H6O3 family. Of the four lowest- energy isomers, only lactic acid [CH3CH(OH)COOH] and dimethyl carbonate [(CH3)2CO3] are commercially available, and lactic acid has been previously investigated spectroscopically. We have therefore conducted a laboratory study of dimethyl carbonate, measuring its rotational spectrum from 8.4 - 25.3 GHz using a Fourier-Transform microwave spectrometer, and from 227 - 350 GHz using a direct absorption spectrometer. We report on the theoretical calculations performed on the C3H6O3 family of isomers, the experimental studies of cis-cis dimethyl carbonate, and the implica- tions of these results for interstellar chemistry. The details of this work are also reported in Lovas et

9. C2H observations toward the Orion Bar

Nagy, Z.; Ossenkopf, V.; Van der Tak, F. F. S.; Faure, A.; Makai, Z.; Bergin, E. A.

2015-06-01

Context. The ethynyl radical (C2H) is one of the first radicals to be detected in the interstellar medium. Its higher rotational transitions have recently become available with the Herschel Space Observatory. Aims: We aim to constrain the physical parameters of the C2H emitting gas toward the Orion Bar. Methods: We analyze the C2H line intensities measured toward the Orion Bar CO+ Peak and Herschel/HIFI maps of C2H, CH, and HCO+ and a NANTEN map of [Ci]. We interpret the observed C2H emission using the combination of Herschel/HIFI and NANTEN data with radiative transfer and PDR models. Results: Five rotational transitions of C2H (from N = 6-5 up to N = 10-9) have been detected in the HIFI frequency range toward the CO+ peak of the Orion Bar. Based on the five detected C2H transitions, a single component rotational diagram analysis gives a rotation temperature of ~64 K and a beam-averaged C2H column density of 4 × 1013 cm-2. The rotational diagram is also consistent with a two-component fit, resulting in rotation temperatures of 43 ± 0.2 K and 123 ± 21 K and in beam-averaged column densities of ~8.3 × 1013 cm-2 and ~2.3 × 1013 cm-2 for the three lower-N and for the three higher-N transitions, respectively. The measured five rotational transitions cannot be explained by any single parameter model. According to a non-LTE model, most of the C2H column density produces the lower-N C2H transitions and traces a warm (Tkin ~ 100-150 K) and dense (n(H2) ~ 105-106 cm-3) gas. A small fraction of the C2H column density is required to reproduce the intensity of the highest-N transitions (N = 9-8 and N = 10-9) originating in a high-density (n(H2) ~5 × 106 cm-3) hot (Tkin ~ 400 K) gas. The total beam-averaged C2H column density in the model is 1014 cm-2. A comparison of the spatial distribution of C2H to those of CH, HCO+, and [Ci] shows the best correlation with CH. Conclusions: Both the non-LTE radiative transfer model and a simple PDR model representing the Orion Bar

10. Applications of 1H-NMR to Biodiesel Research

Technology Transfer Automated Retrieval System (TEKTRAN)

Biodiesel is an alternative diesel fuel derived from vegetable oils, animal fats, or used cooking oils. It is produced by reacting these materials with an alcohol in the presence of a catalyst to give the corresponding mono-alkyl esters. 1H-NMR is a routine analytical method that has been used for...

11. Nuclear receptor NR1H3 in familial multiple sclerosis

PubMed Central

Wang, Zhe; Sadovnick, A. Dessa; Traboulsee, Anthony L.; Ross, Jay P.; Bernales, Cecily Q.; Encarnacion, Mary; Yee, Irene M.; de Lemos, Madonna; Greenwood, Talitha; Lee, Joshua D.; Wright, Galen; Ross, Colin J.; Zhang, Si; Song, Weihong; Vilariño-Güell, Carles

2016-01-01

SUMMARY Multiple sclerosis (MS) is an inflammatory disease characterized by myelin loss and neuronal dysfunction. Despite the aggregation observed in some families, pathogenic mutations have remained elusive. In this study we describe the identification of NR1H3 p.Arg415Gln in seven MS patients from two multi-incident families presenting severe and progressive disease, with an average age at onset of 34 years. Additionally, association analysis of common variants in NR1H3 identified rs2279238 conferring a 1.35-fold increased risk of developing progressive MS. The p.Arg415Gln position is highly conserved in orthologs and paralogs, and disrupts NR1H3 heterodimerization and transcriptional activation of target genes. Protein expression analysis revealed that mutant NR1H3 (LXRA) alters gene expression profiles, suggesting a disruption in transcriptional regulation as one of the mechanisms underlying MS pathogenesis. Our study indicates that pharmacological activation of LXRA or its targets may lead to effective treatments for the highly debilitating and currently untreatable progressive phase of MS. PMID:27253448

12. Complete 1H and 13C spectral assignment of floridoside.

PubMed

Simon-Colin, Christelle; Kervarec, Nelly; Pichon, Roger; Deslandes, Eric

2002-02-11

Floridoside (2-O-alpha-D-galactopyranosylglycerol) was extracted from the red marine alga Rhodymenia palmata, and purified by ion-exchange chromatography: 1D and 2D NMR spectroscopy experiments were used to unambiguously assign the complete 1H and 13C spectra.

13. Electron and Positron Scattering from C3H6 Isomers

Makochekanwa, Casten; Sueoka, Osamu; Kimura, Mineo; Hoshino, Masamitsu; Tanaka, Takahiro; Kitajima, Masashi; Tanaka, Hiroshi

2004-09-01

Hydrocarbons play an important role in high temperature plasmas in Tokamak fusion devices in plasma processing and many other fields [1]. In this paper we report experiments for 0.4-1000 eV electron and 0.2-1000 eV positron total cross sections (TCS) measured using a linear time-of-flight apparatus [2], and electron differential cross sections (DCS) for elastic, vibrational and electronic excitations covering the ranges 1.5 to 100 eV and 15 deg to 130 deg, measured using the crossed beam and relative flow method [3]. The continuum multiple scattering (CMS) [4] calculations have also been performed for the theoretical analysis of the observed features in our cross sections. We observe the isomer effect in both electron and positron TCSs and DCSs. The presence of a dipole moment in propene molecules shows up in enhanced forward scattering in DCSs, leading to larger TCSs and integral cross sections compared to cyclopropane at energies less than 20 eV. However, both electron and positron TCSs for these two molecules nearly equal each other above 100 eV, i.e. the molecular size effect. [1] W. L. Moragn, Adv. At. Mol. Opt. Phys. 43, 79 (2000). [2] O. Sueoka, S. Mori and A. Hamada, J. Phys. B 27, 1453 (1994). [3] H. Tanaka, L. Boesten, D. Matsunaga and T. Kudo, J. Phys. B 21, 1255 (1988). [4] M. Kimura and H. Sato, Comments At. Mol. Phys. 26, 333 (1991).

14. Comparison of dopamine receptor sites labeled by (/sup 3/H)-S-sulpiride and (/sup 3/H)-spiperone in striatum

SciTech Connect

Zahniser, N.R.; Dubocovich, M.L.

1983-12-01

Binding of the radiolabeled active isomer of the neuroleptic sulpiride, (/sup 3/H)-S-sulpiride, to rat and rabbit striatal membranes was characterized. Regardless of whether the specific binding of (/sup 3/H)-S-sulpiride was defined with spiperone or the active isomers of butaclamol or flupenthixol, a single homogeneous++ population of binding sites (rat: Kd . 5.6 nM, maximum binding . 590 fmol/mg of protein; rabbit: Kd . 8.3 nM, maximum binding . 540 fmol/mg of protein) was detected. The pharmacological profile of these sites was characteristic of that described for the dopaminergic D-2 receptor subtype. To determine whether (/sup 3/H)-S-sulpiride and (/sup 3/H)spiperone label common sites in the striatum, the binding of these two radioligands was compared under similar assay conditions. When specific binding of (/sup 3/H)spiperone was defined with S-sulpiride, (/sup 3/H)spiperone labeled the same number of binding sites as (/sup 3/H)-S-sulpiride despite the fact that the affinity of the sites for (/sup 3/H)spiperone was 80- to 90-fold higher than for (/sup 3/H)-S-sulpiride. When specific binding of (/sup 3/H)spiperone was defined with either (+)-butaclamol or (alpha)-flupenthixol, however, approximately 30% more sites were labeled. The predominant site labeled by (/sup 3/H)spiperone also possessed the characteristics of the D-2 receptor. It is concluded that (/sup 3/H)-S-sulpiride under the conditions used is a selective radioligand with which dopamine receptors of the D-2 subtype can be directly measured and localized. (/sup 3/H)Spiperone can be used to detect the same sites only if specific binding is defined with S-sulpiride.

15. In vivo labeling of cocaine receptors with sup 3 H-(-) cocaine, sup 3 H-WIN 35,065-2 and sup 3 H-WIN 35,428

SciTech Connect

Scheffel, U.; Boja, J.W.; Stathis, M.; Kuhar, M.J. )

1990-02-26

{sup 11}C-(-)cocaine (-COC) has recently been employed to image -COC binding sites in vivo using PET. Two analogs of -COC, WIN 35,065-2 (WIN-2) and WIN 35,428 (CFT), have been shown in vitro to exhibit higher affinity for the -COC receptor than -COC. The present study evaluates {sup 3}H-WIN-2 and {sup 3}H-CFT as in vivo receptor labels in mice with a view towards the use of these compounds as PET ligands for -COC receptors in the living human brain. {sup 3}H-labeled -COC, WIN-2 and CFT were injected i.v. into mice and their specific binding in the CNS determined. Peak striatal/cerebellar (S/C) ratios were reached at 5 minutes post injection with -COC (1.56), at 45 minutes with {sup 3}H-WIN-2 (3.30) and 60 minutes with {sup 3}H-CFT (4.0). The specificity of in vivo binding of {sup 3}H-WIN-2 and {sup 3}H-CFT was tested by pre-injection of various drugs. Binding of {sup 3}H-WIN-2 and {sup 3}H-CFT was dose-dependently blocked by cold WIN-2 and CFT, and by dopamine uptake site inhibitors (mazindol, GBR 12,909, nomifensine), but not by (+)COC, paroxetine and desipramine. The data indicate that {sup 3}H-WIN-2 and {sup 3}H-CFT exhibit improved in vivo binding (higher S/C ratios, longer retention time at the -COC receptor/dopamine transporter) compared to -COC and support their testing in PET studies.

16. Stapled Peptides by Late-Stage C(sp(3) )-H Activation.

PubMed

Noisier, Anaïs F M; García, Jesús; Ionuţ, Ioana A; Albericio, Fernando

2017-01-02

Despite the importance of stapled peptides for drug discovery, only few practical processes to prepare cross-linked peptides have been described; thus the structural diversity of available staple motifs is currently limited. At the same time, C-H activation has emerged as an efficient approach to functionalize complex molecules. Although there are many reports on the C-H functionalization of amino acids, examples of post-synthetic peptide C-H modification are rare and comprise almost only C(sp(2) )-H activation. Herein, we report the development of a palladium-catalyzed late-stage C(sp(3) )-H activation method for peptide stapling, affording an unprecedented hydrocarbon cross-link. This method was first employed to prepare a library of stapled peptides in solution. The compatibility with various amino acids as well as the influence of the size (i,i+3 and i,i+4) and length of the staple were investigated. Finally, a simple solid-phase procedure was also established.

17. Ligand-enabled cross-coupling of C(sp3)-H bonds with arylboron reagents via Pd(II)/Pd(0) catalysis

Chan, Kelvin S. L.; Wasa, Masayuki; Chu, Ling; Laforteza, Brian N.; Miura, Masanori; Yu, Jin-Quan

2014-02-01

There have been numerous developments in C-H activation reactions in the past decade. Attracted by the ability to functionalize molecules directly at ostensibly unreactive C-H bonds, chemists have discovered reaction conditions that enable reactions of C(sp2)-H and C(sp3)-H bonds with a variety of coupling partners. Despite these advances, the development of suitable ligands that enable catalytic C(sp3)-H bond functionalization remains a significant challenge. Herein we report the discovery of a mono-N-protected amino acid ligand that enables Pd(II)-catalysed coupling of γ-C(sp3)-H bonds in triflyl-protected amines with arylboron reagents. Remarkably, no background reaction was observed in the absence of ligand. A variety of amine substrates and arylboron reagents were cross-coupled using this method. Arylation of optically active substrates derived from amino acids also provides a potential route for preparing non-proteinogenic amino acids.

18. Magic angle spinning NMR of proteins: high-frequency dynamic nuclear polarization and (1)H detection.

PubMed

Su, Yongchao; Andreas, Loren; Griffin, Robert G

2015-01-01

Magic angle spinning (MAS) NMR studies of amyloid and membrane proteins and large macromolecular complexes are an important new approach to structural biology. However, the applicability of these experiments, which are based on (13)C- and (15)N-detected spectra, would be enhanced if the sensitivity were improved. Here we discuss two advances that address this problem: high-frequency dynamic nuclear polarization (DNP) and (1)H-detected MAS techniques. DNP is a sensitivity enhancement technique that transfers the high polarization of exogenous unpaired electrons to nuclear spins via microwave irradiation of electron-nuclear transitions. DNP boosts NMR signal intensities by factors of 10(2) to 10(3), thereby overcoming NMR's inherent low sensitivity. Alternatively, it permits structural investigations at the nanomolar scale. In addition, (1)H detection is feasible primarily because of the development of MAS rotors that spin at frequencies of 40 to 60 kHz or higher and the preparation of extensively (2)H-labeled proteins.

19. Antifungal properties of wheat histones (H1-H4) and purified wheat histone H1.

PubMed

De Lucca, Anthony J; Heden, Lars-Olof; Ingber, Bruce; Bhatnagar, Deepak

2011-07-13

Wheat ( Triticum spp.) histones H1, H2, H3, and H4 were extracted, and H1 was further purified. The effect of these histones on specific fungi that may or may not be pathogenic to wheat was determined. These fungi included Aspergillus flavus , Aspergillus fumigatus , Aspergillus niger , Fusarium oxysporum , Fusarium verticillioides , Fusarium solani , Fusarium graminearum , Penicillium digitatum , Penicillium italicum , and Greeneria uvicola . Non-germinated and germinating conidia of these fungi were bioassayed separately. The non-germinated and germinating conidia of all Fusarium species were highly susceptible to the mixture (H1-H4) as well as pure H1, with viability losses of 99-100% found to be significant (p < 0.001) at ≤10 μM or less for the histone mixture and pure H1. F. graminearum was the most sensitive to histone activity. The histones were inactive against all of the non-germinated Penicillium spp. conidia. However, they significantly reduced the viability of the germinating conidia of the Penicillium spp. conidia, with 95% loss at 2.5 μM. Non-germinated and germinating conidia viability of the Aspergillus spp. and G. uvicola were unaffected when exposed to histones up to 10 μM. Results indicate that Fusarium spp. pathogenic to wheat are susceptible to wheat histones, indicating that these proteins may be a resistance mechanism in wheat against fungal infection.

20. Light microscopic autoradiographic localization of (/sup 3/H)pirenzepine and (/sup 3/H)(/sup -/)quinuclidinyl benzilate binding in human stellate ganglia

SciTech Connect

Yamamura, H.I.; Watson, M.; Wamsley, J.K.; Johnson, P.C.; Roeske, W.R.

1984-08-13

The LKB Ultrofilm method of autoradiography has been utilized to anatomically localize putative M/sub 1/ and M/sub 2/ muscarinic receptor subtypes in human stellate ganglia. Ten micron sections were labeled in vitro with either 1 nM of the classical antagonist (/sup 3/H)(/sup -/)quinuclidinyl benzilate ((/sup 3/H)(/sup -/)QNB) or 20 nM of the non-classical antagonist (/sup 3/H)pirenzepine ((/sup 3/H)PZ), using 1 ..mu..M atropine sulfate to define non-specific binding for both ligands. The results indicate that (/sup 3/H)(/sup -/)QNB and (/sup 3/H)PZ binding sites are distributed within the principal ganglion cells and nerve bundles.

1. Radioactive contamination of the marine environment: Uptake and distribution of3H in Dunaliella bioculata

Strack, S.; Bonotto, S.; Kirchmann, R.

1980-03-01

The marine flagellate Dunaliella bioculata, which is easily cultivated under laboratory conditions, is a suitable organism for assessing the importance of the radioactive contamination by3H bound to organic molecules. We have studied the uptake of the following tritiated precursors: thymidine-methyl-3H, adenine-2-3H, uridine-5-3H, l-leucine-4-3H, glycine-2-3H, l-arginine-3.4-3H, 1-aspartic acid-2. 3-3H, 1-phenylalanine-2.3-3H, D-glucose-2-3H and D-glucose-6-3H. Under the experimental conditions (2000 lux; incubation time 30 min), all tritiated molecules are taken up by D. bioculata. Their intracellular concentration may reach that of the external medium. However, leucine and adenine accumulate in the algae: their respective concentrations are 10 and 100 times higher than in the culture medium. The molecular distribution of3H has been studied by various biochemical techniques and by sieve chromatography on sepharose 4B. It has been found that more l-leucine-4-3H is incorporated into acid and acetone soluble substances than into proteins. Adenine-2-3H is mainly incorporated into macromolecules of biological significance (RNA, DNA). CsCl gradient centrifugation has shown that the total DNA of Dunaliella is constituted by a major (ϖ=1.707 g/cm3) and by a minor (ϖ=1.693 g/cm3) component.

2. Three new energetic complexes with N,N-bis(1H-tetrazole-5-yl)-amine as high energy density materials: syntheses, structures, characterization and effects on the thermal decomposition of RDX.

PubMed

Yang, Qi; Song, Xiaxia; Zhang, Wendou; Hou, Lei; Gong, Qibing; Xie, Gang; Wei, Qing; Chen, Sanping; Gao, Shengli

2017-02-21

Three new energetic complexes, [Pb(bta)(H2O)]n (1), [PbCu(bta)2(H2O)5]·2H2O (2) and PbCu(bta)2 (3) (H2bta = N,N-bis(1H-tetrazole-5-yl)-amine), have been synthesized and characterised. In particular, 3 was readily synthesized by dehydration of 2 at 190 °C. Single crystal X-ray diffraction revealed that 1 has a 3D framework structure and 2 presents a 3D supermolecular architecture. Thermoanalyses demonstrated that the main frames of 1 and 2 have good thermostabilities up to 314 °C for 1 and 231 °C for 2. Non-isothermal kinetic and thermodynamic parameters of exothermic decomposition processes of 1 and 2 were obtained by Kissinger's and Ozawa's methods. Based on the constant-volume combustion energies measured by a precise rotating-bomb calorimeter, the standard molar enthalpies of formation of 1 and 2 were determined. The calculation of the detonation properties of 1 and 2 and the impact sensitivity tests of 1, 2 and 3 were carried out. In addition, 1, 2 and 3 were explored as combustion promoters to accelerate the thermal decompositions of RDX (1,3,5-trinitro-1,3,5-triazine) by differential scanning calorimetry. Experimental results showed that 1, 2 and 3 can be used as HEDMs in the field of combustion promoters and insensitive 2 can be regarded as a safer form for mass storage and transportation than sensitive 3.

3. Infrared assisted production of 3,4-dihydro-2(1H)-pyridones in solvent-free conditions.

PubMed

Noguez, M Olivia; Marcelino, Vanessa; Rodríguez, Hortensia; Martín, Osnieski; Martínez, Joel O; Arroyo, Gabriel A; Pérez, Francisco J; Suárez, Margarita; Miranda, René

2011-01-01

A green approach for the synthesis of a set of ten 4-aryl substituted-5-alcoxy carbonyl-6-methyl-3,4-dihydro-2(1H)-pyridones using Meldrum's acid has been devised, the absence of solvent and the activation with infrared irradiation in addition to a multicomponent protocol are the main reaction conditions. The transformations proceeded with moderated yields (50-75%) with a reasonable reaction rate (3 h). It is worth noting that two novel molecules of the new class of the bis-3,4-dihydropyridones were also obtained. In addition, a comparison without the use of infrared irradiation was performed.

4. Carbohydrate-electrolyte feedings improve 1 h time trial cycling performance.

PubMed

Jeukendrup, A; Brouns, F; Wagenmakers, A J; Saris, W H

1997-02-01

Carbohydrate-electrolyte (CE) feedings have been shown to improve endurance performance at moderate intensities (60-75% VO2max) and or more than 2 h duration. The effects of CE feedings during high intensity exercise (i.e. > or = 80% VO2 max) of shorter duration (approximately 1 h) are less clear. Therefore the purpose of the present study was to investigate the effect of the ingestion of a 7.6% CE solution during exercise on time trial cycling performance of approximately 1 h. This type of performance testing has been shown to be more reproducible (coefficient of variation 3.35%) than the traditional exercise test to exhaustion. On two occasions and in random order nineteen endurance trained cyclists completed an exercise test requiring the accomplishment of a set amount of work as fast as possible (time trial) under strictly standardized conditions. As the start and during the trials they drank in total 14 ml/kg of either a 7.6% CE solution or artificially flavored and colored water (placebo). Time to complete the set amount of work was significantly reduced and thus performance was significantly increase (p < 0.001) with the CE drink by 2.3%. Time to complete the set amount of work was 58.74 +/- 0.52 min with CE and 60.15 +/- 0.65 min with placebo (p < 0.001). Average workload during the time trials was 297.5 +/- 1.4W and 291.0 +/- 10.3 W, respectively. Subjects exercised at 76.4 +/- 0.7% of their maximal work rate (Wmax) with CE and at 74.8% Wmax with placebo (p < 0.001). It was concluded tht also in relative short term (1h) high intensity (75% Wmax) cycling exercise ingestion of a carbohydrate-electrolyte solution compared to placebo improves performance.

5. Different effects of serotonin antagonists on /sup 3/H-mianserin and /sup 3/H-ketanserin recognition sites

SciTech Connect

Gandolfi, O.; Barbaccia, M.L.; Costa, E.

1985-02-25

In minces prepared from the frontal cortex of rats treated with ketanserin (10 mg/kg i.p.) or mianserin (5 mg/kg i.p.) twice daily for 21 days, the Vmax of the adenylate cyclase stimulated by NE (100 ..mu..M) is attenuated, suggesting that ketanserin and mianserin share with a number of antidepressants the ability to attenuate the adenylate cyclase stimulation by NE. Ketanserin, given with the above mentioned dose schedule for 7 consecutive days, reduced the Bmax of 5HT/sub 2/ recognition sites but failed to change either the Bmax or the apparent Kd of /sup 3/H-mianserin binding. A significant decrease in the Bmax of 5HT/sub 2/ binding sites is elicited also by a single injection of mianserin. This drug also down-regulates its own binding when given twice daily for 3 weeks. From this and other information, it is concluded that ketanserin and mianserin bind to distinct recognition sites. The possibility that 5HT/sub 2/ and mianserin recognition sites are functionally related and that serotonergic synapses are modulated by multiple chemical signals might be considered. 34 references, 3 figures.

6. Meridional Variations of C2H2 and C2H6 in Jupiter's Atmosphere from Cassini CIRS Infrared Spectra

NASA Technical Reports Server (NTRS)

Nixon, C. A.; Achterberg, R. K.; Conrath, B. J.; Irwin, P. G. J.; Fouchet, T.; Parrish, P. D.; Romani, P. N.; Abbas, M.; LeClair, A.; Strobel, D.

2004-01-01

Hydrocarbons such as acetylene (C2H2) and ethane (C2H6) are important tracers in Jupiter's atmosphere, constraining our models of the chemical and dynamical processes. However, our knowledge of the vertical and meridional variations of their abundances has remained sparse. During the flyby of the Cassini spacecraft in December 2000, the Composite Infrared Spectrometer (CIRS) instrument was used to map the spatial variation of emissions from 10-1400 cm(sup -1) (1000-7 microns). In this paper we analyze a zonally-averaged set of CIRS spectra taken at the highest (0.5 cm(sup -1)) resolution, to infer atmospheric temperatures in the stratosphere at 0.5-20 mbar via the v4 band of CH4, and in the troposphere at 150-400 mbar, via the H2 absorption at 600-800 cm(sup -1). Simultaneously, we retrieve the abundances of C2H2 and C2H6 via the v5 and vg bands respectively. Tropospheric absorption and stratospheric emission are highly anti-correlated at the CIRS resolution, introducing a non-uniqueness into the retrievals, such that vertical gradient and column abundance cannot both be found without additional constraints. Assuming profile gradients from photochemical calculations, we show that the column abundance of C2H2 decreases sharply towards the poles by a factor approximately 4, while C2H6 is unchanged in the north and increasing in the south, by a factor approximately 1.8. An explanation for the meridional trends is proposed in terms of a combination of photochemistry and dynamics. Poleward, the decreasing UV flux is predicted to decrease the abundances of C2H2 and C2H6 by factors 2.7 and 3.5 respectively at a latitude 70 deg. However, the lifetime of C2H6 in the stratosphere (5 x 10(exp 9)) is much longer than the dynamical timescale for meridional motions inferred from SL-9 debris (5 x 10(exp 8 s)), and therefore the constant or rising abundance towards high latitudes likely indicates that meridional mixing dominates over photochemical effects. For C2H2, the opposite

7. Ethanol intake and sup 3 H-serotonin uptake II: A study in alcoholic patients using platelets sup 3 H-paroxetine binding

SciTech Connect

Daoust, M.; Boucly, P. ); Ernouf, D. ); Breton, P. ); Lhuintre, J.P.

1991-01-01

The kinetic parameters of {sup 3}H-paroxetine binding and {sup 3}H-serotonin uptake were studied in platelets of alcoholic patients. There was no difference between alcoholic and non alcoholic subjects in {sup 3}H-paroxetine binding. When binding and {sup 3}H-serotonin uptake were studied, in the same plasma of the same subjects, the Vmax of serotonin uptake was increased in alcoholics. The data confirm the involvement of serotonin uptake system in alcohol dependance and suggest that serotonin uptake and paroxetine binding sites may be regulated independently in this pathology.

8. Hydroxylated 2-amino-3H-phenoxazin-3-one derivatives as products of 2-hydroxy-1,4-benzoxazin-3-one (HBOA) biotransformation by Chaetosphaeria sp., an endophytic fungus from Aphelandra tetragona.

PubMed

Zikmundová, Martina; Drandarov, Konstantin; Hesse, Manfred; Werner, Christa

2002-01-01

The biotransformation of the phytoanticipin HBOA and its major degradation metabolites 2-hydroxy-N-(2-hydroxyphenyl)acetamide (7) and N-(2-hydroxyphenyl)acetamide (8) by Chaetosphaeria sp., an endophytic fungus isolated from Aphelandra tetragona, was studied. Three new metabolites could be identified as 2-amino-7-hydroxy-3H-phenoxazin-3-one (12), 2-acetylamino-7-hydroxy-3H-phenoxazin-3-one (13) and 7-hydroxy-2-(2-hydroxyacetyl)-amino-3H-phenoxazin-3-one (14). Structure elucidation of 12 and 13 was performed by MS, 1H, 13C NMR and 2D NMR techniques and confirmed by chemical transformation.

9. Infrared spectroscopy of V2+(H2O) complexes

2012-03-01

Doubly charged vanadium-water complexes are produced by laser vaporization in a pulsed supersonic expansion. Size-selected ions are studied with infrared photodissociation spectroscopy in the O-H stretch region using argon complex predissociation. Density functional theory calculations provide structures and vibrational spectra of these ions. The O-H stretches of V2+(H2O) appear at lower frequencies than those of the free water molecule or V+(H2O). The symmetric stretch is more intense than the asymmetric stretch in both V+(H2O) and V2+(H2O) complexes. Spectra of V2+(H2O)Arn (n = 2-7) show that the coordination of the V2+ is filled with six ligands, i.e. one water and five argon atoms.

10. Quantitative produced water analysis using mobile 1H NMR

Wagner, Lisabeth; Kalli, Chris; Fridjonsson, Einar O.; May, Eric F.; Stanwix, Paul L.; Graham, Brendan F.; Carroll, Matthew R. J.; Johns, Michael L.

2016-10-01

Measurement of oil contamination of produced water is required in the oil and gas industry to the (ppm) level prior to discharge in order to meet typical environmental legislative requirements. Here we present the use of compact, mobile 1H nuclear magnetic resonance (NMR) spectroscopy, in combination with solid phase extraction (SPE), to meet this metrology need. The NMR hardware employed featured a sufficiently homogeneous magnetic field, such that chemical shift differences could be used to unambiguously differentiate, and hence quantitatively detect, the required oil and solvent NMR signals. A solvent system consisting of 1% v/v chloroform in tetrachloroethylene was deployed, this provided a comparable 1H NMR signal intensity for the oil and the solvent (chloroform) and hence an internal reference 1H signal from the chloroform resulting in the measurement being effectively self-calibrating. The measurement process was applied to water contaminated with hexane or crude oil over the range 1-30 ppm. The results were validated against known solubility limits as well as infrared analysis and gas chromatography.

11. sigma opiates and certain antipsychotic drugs mutually inhibit (+)-(/sup 3/H)SKF 10,047 and (/sup 3/H)haloperidol binding in guinea pig brain membranes

SciTech Connect

Tam, S.W.; Cook, L.

1984-09-01

The relationship between binding of antipsychotic drugs and sigma psychotomimetic opiates to binding sites for the sigma agonist (+)-(/sup 3/H)SKF 10,047 (N-allylnormetazocine) and to dopamine D/sub 2/ sites was investigated. In guinea pig brain membranes, (+)-(/sup 3/H)SKF 10,047 bound to single class of sites with a K/sub d/ of 4 x 10/sup -8/ M and a B/sub max/ of 333 fmol/mg of protein. This binding was different from ..mu.., kappa, or delta opiate receptor binding. It was inhibited by opiates that produce psychotomimetic activities but not by opiates that lack such activities. Some antipsychotic drugs inhibited (+)-(/sup 3/H)SKF 10,047 binding with high to moderate affinities in the following order of potency: haloperidol > perphenazine > fluphenazine > acetophenazine > trifluoperazine > molindone greater than or equal to pimozide greater than or equal to thioridazine greater than or equal to chlorpromazine greater than or equal to triflupromazine. However, there were other antipsychotic drugs such as spiperone and clozapine that showed low affinity for the (+)-(/sup 3/H)SKF 10,047 binding sites. Affinities of antipsychotic drugs for (+)-(/sup 3/H)SKF 10,047 binding sites did not correlate with those for (/sup 3/H)spiperone (dopamine D/sub 2/) sites. (/sup 3/H)-Haloperidol binding in whole brain membranes was also inhibited by the sigma opiates pentazocine, cyclazocine, and (+)-(/sup 3/H)SKF 10,047. In the striatum, about half of the saturable (/sup 3/H)haloperidol binding was to (/sup 3/H)spiperone (D/sub 2/) sites and the other half was to sites similar to (+)-(/sup 3/H)SKF 10,047 binding sites. 15 references, 4 figures, 1 table.

12. Toll-Like Receptor 4-Defective C3H/HeJ Mice Are Not More Susceptible than Other C3H Substrains to Infection with Mycobacterium tuberculosis

PubMed Central

Kamath, Arati B.; Alt, Jennifer; Debbabi, Hajer; Behar, Samuel M.

2003-01-01

Mycobacterium tuberculosis produces a variety of molecules capable of activating Toll-like receptors, a family of pattern recognition receptors expressed by macrophages and a variety of other cells. To determine whether Toll-like receptor 4 (TLR4) was critical in resistance to M. tuberculosis infection, we compared the morbidity and mortality of TLR4-defective C3H/HeJ mice to those of TLR4-sufficient C3H mouse substrains. TLR4-defective C3H/HeJ mice and TLR4-sufficient C3H/HeSnJ, C3HeB/FeJ, and C3H/HeOuJ mice were infected by the aerosol route with M. tuberculosis. TLR4-defective C3H/HeJ mice had levels of cytokines in their bronchoalveolar lavage fluids and in vitro mycobacterial antigen-specific recall responses similar to those of other C3H mouse substrains. In addition, bacterial replication and long-term survival of mice following infection appeared to be independent of TLR4. Interestingly, C3HeB/FeJ mice were significantly more susceptible to M. tuberculosis infection, indicating that genetic heterogeneity among inbred C3H mouse substrains modifies resistance to infection. Therefore, cautious interpretation is required when the C3H/HeJ strain is used as a model of a TLR4-defective mouse strain, as there are significant allelic differences between C3H/HeJ and other C3H mouse substrains in response to M. tuberculosis infection. With this caveat, our data indicate that TLR4 may not be required for optimal immunity of mice to M. tuberculosis. PMID:12819102

13. Bupropion inhibits nicotine-evoked [(3)H]overflow from rat striatal slices preloaded with [(3)H]dopamine and from rat hippocampal slices preloaded with [(3)H]norepinephrine.

PubMed

Miller, Dennis K; Sumithran, Sangeetha P; Dwoskin, Linda P

2002-09-01

Bupropion, an efficacious antidepressant and smoking cessation agent, inhibits dopamine and norepinephrine transporters (DAT and NET, respectively). Recently, bupropion has been reported to noncompetitively inhibit alpha3beta2, alpha3beta4, and alpha4beta2 nicotinic acetylcholine receptors (nAChRs) expressed in Xenopus oocytes or established cell lines. The present study evaluated bupropion-induced inhibition of native alpha3beta2* and alpha3beta4* nAChRs using functional neurotransmitter release assays, nicotine-evoked [(3)H]overflow from superfused rat striatal slices preloaded with [(3)H]dopamine ([(3)H]DA), and nicotine-evoked [(3)H]overflow from hippocampal slices preloaded with [(3)H]norepinephrine ([(3)H]NE). The mechanism of inhibition was evaluated using Schild analysis. To eliminate the interaction of bupropion with DAT or NET, nomifensine or desipramine, respectively, was included in the superfusion buffer. A high bupropion concentration (100 microM) elicited intrinsic activity in the [(3)H]DA release assay. However, none of the concentrations (1 nM-100 microM) examined evoked [(3)H]NE overflow and, thus, were without intrinsic activity in this assay. Moreover, bupropion inhibited both nicotine-evoked [(3)H]DA overflow (IC(50) = 1.27 microM) and nicotine-evoked [(3)H]NE overflow (IC(50) = 323 nM) at bupropion concentrations well below those eliciting intrinsic activity. Results from Schild analyses suggest that bupropion competitively inhibits nicotine-evoked [(3)H]DA overflow, whereas evidence for receptor reserve was obtained upon assessment of bupropion inhibition of nicotine-evoked [(3)H]NE overflow. Thus, bupropion acts as an antagonist at alpha3beta2* and alpha3beta4* nAChRs in rat striatum and hippocampus, respectively, across the same concentration range that inhibits DAT and NET function. The combination of nAChR and transporter inhibition produced by bupropion may contribute to its clinical efficacy as a smoking cessation agent.

14. 1-(2,4,6-Trialkylphenyl)-1H-Phospholes with a Flattened P-Pyramid: Synthesis and Reactivity

Keglevich, György

The 1H-phospholes with a 2,4,6-trialkylphenyl substituent on the phosphorus atom synthesized in our laboratories are of aromatic character due to their flattened P-pyramid. Hence, they may undergo aromatic electrophilic substitution, such as Friedel-Crafts acylations. The arylphospholes were functionalized via the regioselective reaction with phosphorus tribromide to give substituted phospholes that may be ligands in rhodium complexes used in hydro-formylations. Despite their aromaticity, the arylphospholes may be involved in Diels-Alder cycloaddition with dienophiles to provide 7-phosphanorbornene derivatives useful in fragmentation - related phosphorylations. At elevated temperature, the aryl-1H-phospholes were converted to the 2H-derivatives by a sigmatropic rearrangement to furnish, after trapping, 1-phosphanorbornadienes. The complexation and the oxidation reactions of the sterically hindered arylphospholes are also discussed.

15. Cortical laminar tau deposits and activated astrocytes in Alzheimer’s disease visualised by 3H-THK5117 and 3H-deprenyl autoradiography

PubMed Central

Lemoine, Laetitia; Saint-Aubert, Laure; Nennesmo, Inger; Gillberg, Per-Göran; Nordberg, Agneta

2017-01-01

Hyperphosphorylated tau protein deposits and, inflammatory processes are characteristic components of Alzheimer disease (AD) pathology. We here aimed to visualize in vitro the distribution of tau deposits and activated astrocytes across the cortical layers in autopsy AD brain tissue using the radiotracers 3H-THK5117 and 3H-deprenyl. 3H-THK5117 and 3H-deprenyl autoradiographies were carried out on frozen brain sections from three AD patients and one healthy control. 3H-THK5117 showed a distinct laminar cortical binding similar to 3H-deprenyl autoradiography, with an extensive binding in the superficial and deep layers of the temporal neocortices, whereas the middle frontal gyrus showed an even binding throughout the layers. Globally, eventhough some differences could be observed, AT8 (tau) and GFAP (astrocyte) immunostaining showed a laminar pattern comparable to their corresponding radiotracers within each AD case. Some variability was observed between the AD cases reflecting differences in disease phenotype. The similar laminar cortical brain distribution of tau deposits and activated astrocytes supports the hypothesis of a close pathological interconnection. The difference in regional binding patterns of 3H-THK5117 and AT8 antibody staining suggest additional tau binding sites detectable by 3H-THK5117. PMID:28374768

16. Effect of hemoglobin on the uptake of /sup 3/H-norepinephrine and /sup 3/H-choline chloride into porcine cerebral arteries

SciTech Connect

Linnik, M.D.; Lee, T.J.F.

1986-03-01

Prolonged constriction of cerebral arteries often follows subarachnoid hemorrhage (SAH). SAH exposes hemoglobin (Hb) to cerebral arteries and Hb has been demonstrated to induce vasoconstriction as well as alter cerebrovascular neurogenic response characteristics. The effect of Hb on uptake of /sup 3/H-norepinephrine (/sup 3/H-NE) and /sup 3/H-choline chloride (/sup 3/H-ChCl) into porcine cerebral arteries was therefore examined. 0.5 to 50 ..mu..M porcine Hb caused a dose-dependent inhibition of /sup 3/H-NE uptake into the anterior (ANT), internal carotid (IC) and middle cerebral (MC) arteries of the pig. IC/sub 50/ values for uptake inhibition were: ANT, 31 ..mu..M; IC, 34 ..mu..M; MC, 37 ..mu..M. Porcine serum albumin (PSA) in the same concentration range also caused a decrease in /sup 3/H-NE uptake. An examination of protein-ligand interactions using column chromatography demonstrated binding of /sup 3/H-NE by both Hb and PSA. This protein binding may be responsible for part of the uptake inhibition. Hb and PSA had little effect on /sup 3/H-ChCl uptake into these arteries.

17. The effect of phencyclidine on [3H]GABA and [3H]flunitrazepam binding in the brain of naive and handling-habituated rats.

PubMed

Lillrank, S M; Oja, S S; Saransaari, P

1995-01-01

The effects of handling and handling combined with phencyclidine (PCP) treatment on GABAergic neurotransmission were studied in Sprague-Dawley rats. The animal material consisted of handling-habituated (HH, for 11 d), acutely handled (naive, N), handling-habituated and PCP-treated (10 mg kg-1 i.p., HH + PCP) and acutely handled (naive) PCP-treated (N + PCP) and unhandled 'control' rats. The binding of [3H]GABA and [3H]flunitrazepam (FLU) was studied with membranes and the release of [3H]GABA with slices prepared from the striatum and frontal cortex. In the striatum the maximal binding capacity (Bmax) and the binding constant (KD) of [3H]GABA were the same in N and HH rats, but in the frontal cortex KD was lower in N rats. KD constants of [3H]FLU were significantly lower in both brain areas in N rats than in HH rats. After PCP treatment both Bmax and KD for [3H]FLU increased in these two brain areas in handling-habituated rats, whereas Bmax of [3H]GABA diminished. Neither handling nor PCP had any effect on [3H]GABA release from striatal and frontal cortical slices. Handling prior to killing thus affects differently the GABAergic parameters studied and modulates the PCP-induced effects.

18. HCO, c-C3H and CF+: three new molecules in diffuse, translucent and "spiral-arm" clouds

Liszt, H. S.; Pety, J.; Gerin, M.; Lucas, R.

2014-04-01

Aims: We observe molecular absorption from diffuse clouds across the 3 mm receiver band. Methods: We used the EMIR receiver and FTS spectrometer at the IRAM 30 m telescope to construct absorption spectra toward bright extra-galactic background sources at 195 kHz spectral resolution (≈0.6 km s-1). We used the IRAM Plateau de Bure Interferometer to synthesize absorption spectra of H13CO+ and HCO toward the galactic HII region W49. Results: HCO, c-C3H and CF+ were detected toward the blazars BL Lac and 3C 111 having EB - V = 0.32 and 1.65 mag. HCO was observed in absorption from "spiral-arm" clouds in the galactic plane occulting W49. The complement of detectable molecular species in the 85-110 GHz absorption spectrum of diffuse/translucent gas is now fully determined at rms noise level δτ ≈ 0.002 at EB - V = 0.32 mag (AV = 1 mag) and δτ/EB - V≈ 0.003 mag-1 overall. Conclusions: As with OH, HCO+ and C2H, the relative abundance of c-C3H varies little between diffuse and dense molecular gas, with N(c-C3H)/N(o-c-C3H2) ≈ 0.1. We find N(CF+)/N(H13CO+) ≈ 5, N(CF+)/N(C2H) ≈ 0.005-0.01 and because N(CF+) increases with EB - V and with the column densities of other molecules we infer that fluorine remains in the gas phase as HF well beyond AV = 1 mag. We find N(HCO)/N(H13CO+) = 16 toward BL Lac, 3C 111 and the 40 km s-1 spiral arm cloud toward W49, implying X(HCO) ≈10-9, about 10 times higher than in dark clouds. The behaviour of HCO is consistent with previous suggestions that it forms from C+ and H2, even when AV is well above 1 mag. The survey can be used to place useful upper limits on some species, for instance N(H2CO)/N(H2CS) > 32 toward 3C 111, compared to 7 toward TMC-1, confirming the possibility of a gas phase formation route to H2CO. In general, however, the hunt for new species will probably be more fruitful at cm- and sub-mm wavelengths for the near future.

19. Construction of recombinant pEGFP-N1-hPer2 plasmid and its expression in osteosarcoma cells.

PubMed

Cheng, Anyuan; Zhang, Yan; Mei, Hongjun; Fang, Shuo; Ji, Peng; Yang, Jian; Yu, Ling; Guo, Weichun

2016-04-01

The aim of this study was to construct the eukaryotic expression vector pEGFP-N1-hPer2 and assess its expression in the human osteosarcoma cell line MG63. Total mRNA was extracted from human osteosarcoma MG63 cells, the human period 2 (hPer2) gene was obtained by reverse transcription-polymerase chain reaction (RT-PCR) and cloned into the pEGFP-N1 vector, then the recombinant pEGFP-N1-hPer2 plasmid was constructed and transfected into MG63 cells using Lipofectamine 2000. The expression of hPer2 in MG63 cells was measured by quantitative RT-PCR and western blot analysis. The accurate construction of pEGFP-N1-hPer2 was verified by double enzyme digestion and DNA sequencing. hPer2 gene expression in the transfected cells was assessed by RT-qPCR and western blot analysis. In conclusion, the recombinant pEGFP-N1-hPer2 plasmid was constructed successfully, and expressed effectively in MG63 cells.

20. High-frequency observations of δ2H and δ18O in storm rainfall

Stoecker, F.; Klaus, J.; Pangle, L. A.; Garland, C.; McDonnell, J. J.

2012-12-01

Stable isotopes ratios of hydrogen (2H/1H) and oxygen (18O/16O) are indispensable tools for investigation of the hydrologic cycle. Recent technological advances with laser spectroscopy now enable high-frequency measurement of key water cycle components. While the controls on rainfall isotope composition have been known generally for some time, our understanding of the effect of inter- and intra-storm processes on fine scale rainfall isotope composition is poorly understood. Here we present a new approach to observe inter- and intra-storm isotope variability in precipitation in high-frequency. We investigate the temporal development of δ2H and δ18O within and between discrete rainstorm. δ2H and δ18O in precipitation was measured from November 2011 to February 2012 in Corvallis, OR using a flow-cell combined with a Liquid Water Isotope Analyzer (LWIA-24d, Los Gatos Research, Inc.). The average sample frequency was 15 samples per hour, resulting in more than 3100 samples during the observation period. 27 separate rainstorms were identified in the dataset based on minimum inter-event time, minimum precipitation depth, and minimum number of isotope measurements. Event meteoric water lines were developed for each event. We observed short-term isotopic patterns (e.g., V-shaped trends), high-rate changes (5.3‰/h) and large absolute changes in isotopic composition (20‰) on intra-event scale. V-shaped trends appeared to be related to individual storm fronts detected by air temperature, cloud heights (NEXRAD radar echo tops) and cloud trajectories (Hybrid Single Particle Lagrangian Integrated Trajectory Model (HYSPLIT)). Despite this, we could detect no linear correlation between event-based isotopic variables (slope, δ2H-intercept, δ2H, δ18O) and the event meteoric water line. Furthermore, the composite event meteoric water line (i.e. the local meteoric water line) showed a wider spread for heavy isotopes than for light isotopes, caused presumably by different

1. Meridional Variations of C2H2 and C2H6 in Jupiter's Atmosphere from Cassini CIRS Infrared Spectra

NASA Technical Reports Server (NTRS)

Nixon, C. A.; Achterberg, R. K.; Conrath, B. J.; Irwin, P. G. J.; Fouchet, T.; Parrish, P. D.; Abbas, M.; LeClaire, A.; Romani, P. N.; Simon-Miller, A. A.

2004-01-01

The abundances of hydrocarbons such as acetylene (C2H2) and ethane (C2H6) in Jupiter's atmosphere are important physical quantities, constraining our models of the chemical and dynamical processes. However, our knowledge of these quantities and their vertical and latitudinal variations has remained sparse. The flyby of the Cassini spacecraft with Jupiter at the end of 2000 provided an excellent opportunity to observe the infrared spectrum with the Composite Infrared Spectrometer (CIRS) instrument, mapping the spatial variation of emissions from 10-1400 cm-1. CIRS spectra taken at the highest resolution (0.5 cm-1) in early December 2000 have been analysed to infer atmospheric temperatures in the stratosphere at 0.5-20 mbar via the v4 of CH4, and in the troposphere at 100-400 mbar, via the hydrogen collision-induced continuum absorption at 600-800 cm. Simultaneously, we have searched for meridional abundance variations in C2H2 and C2H6 via the v5 and vg bands respectively. Tropospheric absorption and stratospheric emission are highly anti-correlated at the CIM resolution, introducing a non-uniqueness into the retrievals, which means that vertical gradient and column abundance cannot be simultaneously found without additional constraints. If we assume the profile shapes from photochemical model calculations, we show that the column abundance of C2H2 must decrease sharply towards the poles, while C2H6 is constant or slightly increasing. The relevance of these results to current photochemical and dynamical knowledge of Jupiter's atmosphere is discussed.

2. The distribution and abundance of interstellar C2H

NASA Technical Reports Server (NTRS)

Huggins, P. J.; Carlson, W. J.; Kinney, A. L.

1984-01-01

C2H(N = 1-0) emission has been extensively observed in a variety of molecular clouds, including: 12 hot, dense, cloud cores, 3 bright-rimmed clouds (in NGC 1977, IC 1396, and IC 1848), and across the extended OMC - 1 cloud. It has also been observed in the circumstellar envelopes IRC + 10216 and AFGL 2688. Abundance analyses of the molecular clouds yield C2H/(C-13)O abundance ratios of about 0.01, with little variation (less than about a factor of 4) either between clouds or across individual clouds. In the Orion plateau source, the C2H abundance is enhanced by less than a factor of 4, relative to the extended cloud. The generally high levels of C2H found in the molecular clouds are not readily accounted for by simple, steady-state chemical models, and suggest, as do earlier observations of atomic carbon, that the carbon chemistry in dense clouds is more active than is commonly assumed.

3. Evaluation of an electrochemical N2/H2 gas separator

NASA Technical Reports Server (NTRS)

Marshall, R. D.; Wynveen, R. A.; Carlson, J. N.

1973-01-01

A program was successfully completed to evaluate an electrochemical nitrogen/hydrogen (N2/H2) separator for use in a spacecraft nitrogen (N2) generator. Based on the technical data obtained a N2/H2 separator subsystem consisting of an organic polymer gas permeator first stage and an electrochemical second and third stage was estimated to have the lowest total spared equivalent weight, 257 kg (566 lb), for a 15 lb/day N2 generation rate. A pre-design analysis of the electrochemical N2/H2 separator revealed that its use as a first stage resulted in too high a power requirement to be competitive with the organic polymer membrane and the palladium-silver membrane separation methods. As a result, program emphasis was placed on evaluating the electrochemical. A parametric test program characterized cell performance and established second- and third-stage electrochemical N2/H2 separator operating conditions. A design verification test was completed on the second and third stages. The second stage was then successfully endurance tested for 200 hours.

4. Proton-detected 3D (1)H/(13)C/(1)H correlation experiment for structural analysis in rigid solids under ultrafast-MAS above 60 kHz.

PubMed

Zhang, Rongchun; Nishiyama, Yusuke; Ramamoorthy, Ayyalusamy

2015-10-28

A proton-detected 3D (1)H/(13)C/(1)H chemical shift correlation experiment is proposed for the assignment of chemical shift resonances, identification of (13)C-(1)H connectivities, and proximities of (13)C-(1)H and (1)H-(1)H nuclei under ultrafast magic-angle-spinning (ultrafast-MAS) conditions. Ultrafast-MAS is used to suppress all anisotropic interactions including (1)H-(1)H dipolar couplings, while the finite-pulse radio frequency driven dipolar recoupling (fp-RFDR) pulse sequence is used to recouple dipolar couplings among protons and the insensitive nuclei enhanced by polarization transfer technique is used to transfer magnetization between heteronuclear spins. The 3D experiment eliminates signals from non-carbon-bonded protons and non-proton-bonded carbons to enhance spectral resolution. The 2D (F1/F3) (1)H/(1)H and 2D (13)C/(1)H (F2/F3) chemical shift correlation spectra extracted from the 3D spectrum enable the identification of (1)H-(1)H proximity and (13)C-(1)H connectivity. In addition, the 2D (F1/F2) (1)H/(13)C chemical shift correlation spectrum, incorporated with proton magnetization exchange via the fp-RFDR recoupling of (1)H-(1)H dipolar couplings, enables the measurement of proximities between (13)C and even the remote non-carbon-bonded protons. The 3D experiment also gives three-spin proximities of (1)H-(1)H-(13)C chains. Experimental results obtained from powder samples of L-alanine and L-histidine ⋅ H2O ⋅ HCl demonstrate the efficiency of the 3D experiment.

5. Proton-detected 3D 1H/13C/1H correlation experiment for structural analysis in rigid solids under ultrafast-MAS above 60 kHz

Zhang, Rongchun; Nishiyama, Yusuke; Ramamoorthy, Ayyalusamy

2015-10-01

A proton-detected 3D 1H/13C/1H chemical shift correlation experiment is proposed for the assignment of chemical shift resonances, identification of 13C-1H connectivities, and proximities of 13C-1H and 1H-1H nuclei under ultrafast magic-angle-spinning (ultrafast-MAS) conditions. Ultrafast-MAS is used to suppress all anisotropic interactions including 1H-1H dipolar couplings, while the finite-pulse radio frequency driven dipolar recoupling (fp-RFDR) pulse sequence is used to recouple dipolar couplings among protons and the insensitive nuclei enhanced by polarization transfer technique is used to transfer magnetization between heteronuclear spins. The 3D experiment eliminates signals from non-carbon-bonded protons and non-proton-bonded carbons to enhance spectral resolution. The 2D (F1/F3) 1H/1H and 2D 13C/1H (F2/F3) chemical shift correlation spectra extracted from the 3D spectrum enable the identification of 1H-1H proximity and 13C-1H connectivity. In addition, the 2D (F1/F2) 1H/13C chemical shift correlation spectrum, incorporated with proton magnetization exchange via the fp-RFDR recoupling of 1H-1H dipolar couplings, enables the measurement of proximities between 13C and even the remote non-carbon-bonded protons. The 3D experiment also gives three-spin proximities of 1H-1H-13C chains. Experimental results obtained from powder samples of L-alanine and L-histidine ṡ H2O ṡ HCl demonstrate the efficiency of the 3D experiment.

6. Temperature dependent product yields for the spin forbidden singlet channel of the C(3P) + C2H2 reaction

Hickson, Kevin M.; Loison, Jean-Christophe; Wakelam, Valentine

2016-08-01

The atomic hydrogen formation channels of the C + C2H2 reaction have been investigated using a continuous supersonic flow reactor over the 52-296 K temperature range. H-atoms were detected directly at 121.567 nm by vacuum ultraviolet laser induced fluorescence. Absolute H-atom yields were determined by comparison with the H-atom signal generated by the C + C2H4 reaction. The product yields agree with earlier crossed beam experiments employing universal detection methods. Incorporating these branching ratios in a gas-grain model of dense interstellar clouds increases the c-C3H abundance. This reaction is a minor source of C3-containing molecules in the present simulations.

7. Quantifying unfrozen water in frozen soil by high-field 2H NMR.

PubMed

Sparrman, Tobias; Oquist, Mats; Klemedtsson, Leif; Schleucher, Jürgen; Nilsson, Mats

2004-10-15

To understand wintertime controls of biogeochemical processes in high latitude soils it is essential to distinguish between direct temperature effects and the effects of changes in water availability mediated by freezing. Efforts to separate these controls are hampered by a lack of adequate methods to determine the proportion of unfrozen water. In this study we present a high-field 2H2O NMR method for quantifying unfrozen water content in frozen soil. The experimental material consisted of the humic layer of a boreal spruce forest soil mixed with varying proportions of quartz sand and humidified with deuterium-enriched water. The relative standard deviation of unfrozen water content (measured as NMR signal integral) was less than 2% for repeated measurements on a given sample and 3.5% among all samples, based on a total of 16 measurements. As compared to 1H NMR, this 2H NMR method was found to be superior for several reasons: it is less sensitive to field inhomogeneity and paramagnetic impurities, it gives a bigger line shape difference between the ice and liquid signal, it shows a sharper response to water fusion, and it excludes the possibility of hydrogen in the organic material interfering with the measurement.

8. Proton-detected 3D 14N/14N/1H isotropic shift correlation experiment mediated through 1H-1H RFDR mixing on a natural abundant sample under ultrafast MAS

Pandey, Manoj Kumar; Nishiyama, Yusuke

2015-09-01

In this contribution, we have demonstrated a proton detection-based approach on a natural abundant powdered L-Histidine HCl-H2O sample at ultrafast magic angle spinning (MAS) to accomplish 14N/14N correlation from a 3D 14N/14N/1H isotropic shift correlation experiment mediated through 1H finite-pulse radio frequency-driven recoupling (fp-RFDR). Herein the heteronuclear magnetization transfer between 14N and 1H has been achieved by HMQC experiment, whereas 14N/14N correlation is attained through enhanced 1H-1H spin diffusion process due to 1H-1H dipolar recoupling during the RFDR mixing. While the use of ultrafast MAS (90 kHz) provides sensitivity enhancement through increased 1H transverse relaxation time (T2), the use of micro-coil probe which can withstand strong 14N radio frequency (RF) fields further improves the sensitivity per unit sample volume.

9. Complete assignment of NMR data of 22 phenyl-1H-pyrazoles' derivatives.

PubMed

de Oliveira, Aline Lima; Alves de Oliveira, Carlos Henrique; Mairink, Laura Maia; Pazini, Francine; Menegatti, Ricardo; Lião, Luciano Morais

2011-08-01

Complete assignment of (1)H and (13)C NMR chemical shifts and J((1)H/(1)H and (1)H/(19)F) coupling constants for 22 1-phenyl-1H-pyrazoles' derivates were performed using the concerted application of (1)H 1D and (1)H, (13)C 2D gs-HSQC and gs-HMBC experiments. All 1-phenyl-1H-pyrazoles' derivatives were synthesized as described by Finar and co-workers. The formylated 1-phenyl-1H-pyrazoles' derivatives were performed under Duff's conditions.

10. Design, synthesis and evaluation of [(3)H]PF-7191, a highly specific nociceptin opioid peptide (NOP) receptor radiotracer for in vivo receptor occupancy (RO) studies.

PubMed

Zhang, Lei; Drummond, Elena; Brodney, Michael A; Cianfrogna, Julie; Drozda, Susan E; Grimwood, Sarah; Vanase-Frawley, Michelle A; Villalobos, Anabella

2014-11-15

Herein we report the identification of (+)-N-(2-((1H-pyrazol-1-yl)methyl)-3-((1R,3r,5S)-6'-fluoro-8-azaspiro[bicyclo[3.2.1]octane-3,1'-isochroman]-8-yl)propyl)-N-[(3)H]-methylacetamide {[(3)H]PF-7191 [(+)-11]} as a promising radiotracer for the nociceptin opioid peptide (NOP) receptor. (+)-11 demonstrated high NOP binding affinity (Ki = 0.1 nM), excellent selectivity over other opioid receptors (>1000×) and good brain permeability in rats (C(b,u)/C(p,u) = 0.29). Subsequent characterization of [(3)H](+)-11 showed a high level of specific binding and a brain bio-distribution pattern consistent with known NOP receptor expression. Furthermore, the in vivo brain binding of [(3)H](+)-11 in rats was inhibited by a selective NOP receptor antagonist in a dose-responsive manner. This overall favorable profile indicated that [(3)H](+)-11 is a robust radiotracer for pre-clinical in vivo receptor occupancy (RO) measurements and a possible substrate for carbon-11 labeling for positron emission tomography (PET) imaging in higher species.

11. Differentiation between cortical atrophy and hydrocephalus using 1H MRS.

PubMed

Bluml, S; McComb, J G; Ross, B D

1997-03-01

Quantitative 1H MRS to determine cerebral metabolite patterns and MRI to determine CSF flow were applied to 12 patients with ventricular dilation-Group A, cortical atrophy (N = 5); or Group B, hydrocephalus (N = 7)- and in 9 normal controls. While mean brain water (Group A = 80% +/- 6; Group B = 86% +/- 5; normal = 85% +/- 4) did not differ between the two groups of patients and controls, 1H MRS distinguished those patients with cortical atrophy (Group A) (N-acetylaspartate/ creatine (NAA/Cr) = 0.69 +/- 0.17, versus normal = 1.06 +/- 0.16; P < 0.002; [NAA] = 5.9 +/- 1.3 mmoles/kg, versus normal 8.0 +/- 1.4; P < 0.02) from those with hydrocephalus (Group B) (NAA/Cr = 1.16 +/- 0.11; [NAA] = 9.2 +/- 1.2; P > 0.13 and P > 0.07). Lactate levels were elevated in 3/5 patients with cortical atrophy, but in 0/7 of those with hydrocephalus. Mean absolute concentrations (mmoles/kg) of the five major cerebral osmolytes were 41 +/- 4 (Group A), 43 +/- 6 (Group B), and 42 +/- 4 (normal), so that despite massive brain deformation, constant osmolality was maintained. 1H MRS may directly benefit surgical planning in hydrocephalus infants by clearly identifying those with cortical atrophy who do not require CSF diversion. Thinning of the cortical mantle in hydrocephalus may result from osmotically driven reduction in individual cell volumes, (shrinkage), rather than brain-compression.

12. A theoretical study of the CH[sub 3]+C[sub 2]H[sub 2] reaction

SciTech Connect

Diau, E.W.; Lin, M.C. ); Melius, C.F. )

1994-09-01

The rate constants for the formation of various products in the CH[sub 3]+C[sub 2]H[sub 2] reaction have been computed by multichannel RRKM calculations using the molecular and transition-state parameters predicted by the BAC-MP4 method. The results of the calculations agree quantitatively with experimental data obtained under varying conditions: [ital T]=300--2200 K, [ital P]=30--2500 Torr. At low temperatures ([ital T][lt]1300 K), the CH[sub 3]+C[sub 2]H[sub 2] reaction is dominated by the addition-stabilization process producing CH[sub 3]C[sub 2]H[sub 2]. Under high-temperature ([ital T][gt]1400 K) and atmospheric-pressure conditions, the reaction occurs primarily by the CH[sub 3]-for-H displacement process producing CH[sub 3]C[sub 2]H, a likely source of the C[sub 3]H[sub 3] radical (which has recently been shown to be a key precursor of C[sub 6]H[sub 6] in hydrocarbon combustion reactions).

13. Photoaffinity labeling of opiate receptors using intrinsically photoactive /sup 3/H-opiates

SciTech Connect

Kooper, G.N.; Levinson, N.R.; Copeland, C.F.; Bowen, W.D.

1988-03-01

Opiate receptors in rat and cow brain membranes have been labeled irreversibly using the intrinsic photolability of 3H-opiates. Membranes were incubated with 3H-ligand and then irradiated with UV light of 254 nm. Nonspecific binding was determined in the presence of 10 microM unlabeled levallorphan. Irreversible binding was defined as binding which survived heat or acid denaturation of membranes. Specific incorporation of label into denatured samples was observed only when unbound or loosely bound 3H-ligand was washed free from the membranes prior to irradiation. There was a general correlation between photosensitivity of the 3H-ligand and its ability to photolabel receptors. Hence, photolabeling presumably results by covalent attachment of highly reactive species generated during photochemical decomposition of ligand. With 3H-etorphine, optimal irradiation time was 5 min. In addition to 3H-etorphine, receptors could be labeled irreversibly with 3H-oxymorphone, 3H-dihydromorphine, and 3H-ethylketocyclazocine. Of the specific binding present in irradiated, nondenatured samples, 45-60% remained attached to receptors upon denaturation. 3H-Ethylketocyclazocine exhibited an 86% yield of incorporation. Signal-to-noise levels of 50-80% could be achieved in denatured samples. Therefore, this method provides a means of covalently labeling opiate receptors in high yield and with high signal-to-noise ratios. The opioid peptides, 3H-D-Ala2,D-Leu5-enkephalin, 3H-D-Ser2,Leu5,Thr6-enkephalin, 3H-D-Ala2,Met5-enkephalin amide, and 3H-D-Ala2,N-MePhe4,Gly-ol5-enkephalin, as well as the benzomorphan, 3H-bremazocine, apparently lack the structural characteristics which allow photolabeling.

14. SMA OBSERVATIONS OF THE W3(OH) COMPLEX: PHYSICAL AND CHEMICAL DIFFERENTIATION BETWEEN W3(H{sub 2}O) AND W3(OH)

SciTech Connect

Qin, Sheng-Li; Schilke, Peter; Sánchez-Monge, Álvaro; Wu, Jingwen; Wu, Yuefang; Liu, Tie; Liu, Ying

2015-04-10

We report on the Submillimeter Array (SMA) observations of molecular lines at 270 GHz toward the W3(OH) and W3(H{sub 2}O) complex. Although previous observations already resolved the W3(H{sub 2}O) into two or three sub-components, the physical and chemical properties of the two sources are not well constrained. Our SMA observations clearly resolved the W3(OH) and W3(H{sub 2}O) continuum cores. Taking advantage of the line fitting tool XCLASS, we identified and modeled a rich molecular spectrum in this complex, including multiple CH{sub 3}CN and CH{sub 3}OH transitions in both cores. HDO, C{sub 2}H{sub 5}CN, O{sup 13}CS, and vibrationally excited lines of HCN, CH{sub 3}CN, and CH{sub 3}OCHO were only detected in W3(H{sub 2}O). We calculate gas temperatures and column densities for both cores. The results show that W3(H{sub 2}O) has higher gas temperatures and larger column densities than W3(OH) as previously observed, suggesting physical and chemical differences between the two cores. We compare the molecular abundances in W3(H{sub 2}O) to those in the Sgr B2(N) hot core, the Orion KL hot core, and the Orion Compact Ridge, and discuss the chemical origin of specific species. An east–west velocity gradient is seen in W3(H{sub 2}O), and the extension is consistent with the bipolar outflow orientation traced by water masers and radio jets. A north–south velocity gradient across W3(OH) is also observed. However, with current observations we cannot be assured whether the velocity gradients are caused by rotation, outflow, or radial velocity differences of the sub-components of W3(OH)

15. Spectroscopic Studies of the H_3^+ + H_2 Reaction at Astrophysically Relevant Temperatures

Tom, Brian A.; McGuire, Brett A.; Moore, Lauren E.; Wood, Thomas J.; McCall, Benjamin J.

2009-06-01

H_3^+ is the key precursor to ion chemistry in the interstellar medium. It has been employed as an astrophysical probe of conditions of temperature and density due to its ubiquity in a variety of environments. The distribution of ortho- and para- spin modifications of H_3^+ is particularly interesting in this regard. Consequently, it is important to understand the pathways through which changes to the H_3^+ spin distribution can occur. One possible pathway is the H_3^+ + H_2 → H_2 + H_3^+ reaction, which proceeds by proton hop and proton exchange and is governed by the conservation of nuclear spin. Cordonnier et al. studies this reaction at high temperature in a pulsed hollow cathode cell, but to facilitate the understanding of astronomical observations, we need lower temperature measurements. Recently, we have constructed a liquid nitrogen-cooled hollow cathode discharge source and coupled it with multipass absorption spectroscopy to measure the ortho:para ratio of H_3^+ in plasmas at a variety of para-H_2 enrichment levels at ˜160 K. Previously, we have reported experimental measurements of the branching ratio between proton hop and exchange in a hydrogenic plasma at ˜80 K. Together, these experiments have allowed us to explore the temperature dependence of this branching ratio and provide valuable information for the interpretation of astronomical observations. [1] M. Cordonnier et al., J Chem Phys, 113, 3181 (2000) [2] B. A. Tom, M. B. Wiczer, A. A. Mills, K. N. Crabtree, and B. J. McCall, Observation of nuclear spin selection rules in supersonically expanding plasmas containing H_3^+,'' 63rd International Symposium on Molecular Spectroscopy (2008).

16. Copper nitrate catalyzed three-component one-pot synthesis of 3,4-dihydropyrimidin-2(1H)-ones.

PubMed

Wang, Min; Jiang, Heng; Song, Zhiguo; Gong, Hong

2009-01-01

An efficient synthesis of 3,4-dihydropyrimidin-2(1H)-ones from aldehydes, 1,3-dicarbonyl compounds, and urea using copper nitrate under refluxing temperature in ethanol was described. Compared with other Lewis copper salts, copper nitrate proved to be the most efficient. The advantages of the new method were good yields (61-93%), short reaction time (0.4-3 h), and inexpensive catalyst.

17. Search for the isomers of C2H3NO and C2H3NS in the Interstellar Medium

Etim, Emmanuel; Chakrabarti, Sandip Kumar; Das, Ankan; Gorai, Prasanta; Arunan, Elangannan

2016-07-01

With about 40% of all the known interstellar and circumstellar molecules having their isomeric analogues as known astromolecules, isomerism remains one of the leading themes in interstellar chemistry. In this regard, the recent detection of methyl isocyanate (with a number of isomeric analogues) in the Sgr B2(N) giant molecular cloud opens a new window for the possible astronomical detection of other C_2H_3NO isomers. The present work looks at the possibility of detecting other isomers of methyl isocyanate by considering different factors such as thermodynamic stability of the different isomers with respect to the Energy, Stability and Abundance (ESA) relationship, effect of interstellar hydrogen bonding with respect to the formation these isomers on the surface of the interstellar dust grains, possible formation routes for these isomers, spectroscopic parameters for potential astromolecules among these isomers, chemical modeling among other studies. The same studies are repeated for the C_2H_3NS isomers which are the isoelectroninc analogues of the C_2H_3NO isomers taking into account the unique chemistry of S and O-containing interstellar molecular species. Among the C_2H_3NS isomers, methyl isothiocyanate remains the most potential candidate for astronomical observation.

18. Observations of CH4, C2H6, and C2H2 in the stratosphere of Jupiter.

PubMed

Sada, P V; Bjoraker, G L; Jennings, D E; McCabe, G H; Romani, P N

1998-12-01

We have performed high-resolution spectral observations at mid-infrared wavelengths of CH4 (8.14 micrometers), C2H6 (12.16 micrometers), and C2H2 (13.45 micrometers) on Jupiter. These emission features probe the stratosphere of the planet and provide information on the carbon-based photochemical processes taking place in that region of the atmosphere. The observations were performed using our cryogenic echelle spectrometer CELESTE, in conjunction with the McMath-Pierce 1.5-m solar telescope between November 1994 and February 1995. We used the methane observations to derive the temperature profile of the jovian atmosphere in the 1-10 mbar region of the stratosphere. This profile was then used in conjunction with height-dependent mixing ratios of each hydrocarbon to determine global abundances for ethane and acetylene. The resulting mixing ratios are 3.9(+1.9)(-1.3) x 10(-6) for C2H6 (5 mbar pressure level), and 2.3 +/- 0.5 x 10(-8) for C2H2 (8 mbar pressure level), where the quoted uncertainties are derived from model variations in the temperature profile which match the methane observation uncertainties.

19. Characterization of antralin: an endogenous protein inhibitor of radioligand binding to (/sup 3/H)RO 5-4864 and (/sup 3/H)nitrendipine binding sites

SciTech Connect

Mantione, C.R.; Goldman, M.E.; Bolger, G.T.; Lueddens, H.W.M.; Paul, S.M.; Skolnick, P.

1986-03-01

The presence of substances isolated from rat antral stomach that inhibit the binding of (/sup 3/H)Ro 5-4864 (4'-chlorodiazepam) to peripheral-type benzodiazepine receptors (PBR), but do not affect the binding of (/sup 3/H)diazepam to brain-type benzodiazepine receptors have been described. These substances, now obtained by isolation on Sep-Pak C/sub 18/ cartridges, also had no effect on (/sup 3/)PK 11195 binding which labels an antagonist site associated with PBR. Neither was any significant inhibition of (/sup 3/H)Ro 15-1788, (/sup 3/H)..beta..CCM, or (/sup 3/H)dihydroalprenolol binding observed. However, the Sep-Pak eluates were found to produce a concentration-dependent inhibition of (/sup 3/H)nitrendipine binding equivalent to that seen with (/sup 3/H)Ro 5-4864. This material, termed antralin, reduced the apparent K/sub d/ of both radioligands without significantly affecting B/sub max/. Its activity was destroyed by both heat treatment and pronase, and partially reduced by trypsin. Furthermore, its activity was enhanced by Ca/sup + +/ (0.1 mM). Antralin levels were unevenly distributed in rat tissues. These findings suggest that antralin is a protein that may regulate both PBR and dihydropyridine Ca/sup + +/-channel antagonist binding sites in vivo.

20. Autoradiographic analysis of the in vivo distribution of 3H-imipramine and 3H-desipramine in brain: Comparison to in vitro binding patterns

SciTech Connect

Duncan, G.E.; Paul, I.A.; Fassberg, J.B.; Powell, K.R.; Stumpf, W.E.; Breese, G.R. )

1991-03-01

Using high resolution autoradiographic techniques, the distribution of radioactivity in forebrain and brainstem was assessed after 4 injection of 3H-impramine or 3H-desipramine. Results were compared with regional binding of the drugs to brain sections in vitro. Similar topographic binding of 3H-imipramine and 3H-desipramine was observed in vitro among brain regions, except in the paraventricular nucleus of the hypothalamus and locus coeruleus, where binding was greater for 3H-desipramine. For both 3H-desipramine and 3H-imipramine, some brain regions that exhibited high binding in vitro also showed high accumulation after in vivo injection. However, certain regions that contained high densities of binding sites for the antidepressant drugs as measured by in vitro binding showed very low accumulation of radioactivity after in vivo treatment. Such regions included the dentate gyrus of the hippocampus, layer 1 of piriform cortex, caudate-putamen, pontine and midbrain central gray, and cerebellar granular layer. Compared to in vitro binding of the drugs, the distribution of imipramine and desipramine in vivo appears more anatomically selective. For imipramine, primary sites of action in vivo, as indicated by the topographic distribution in brain, appear to be the locus coeruleus, hippocampus, lateral septal nucleus, and amygdala. For desipramine, the greatest accumulation in vivo was found in the locus coeruleus, paraventricular nucleus of the hypothalamus, and anterior thalamic nuclei.

1. The 1H NMR Profile of Healthy Dog Cerebrospinal Fluid

PubMed Central

Musteata, Mihai; Nicolescu, Alina; Solcan, Gheorghe; Deleanu, Calin

2013-01-01

The availability of data for reference values in cerebrospinal fluid for healthy humans is limited due to obvious practical and ethical issues. The variability of reported values for metabolites in human cerebrospinal fluid is quite large. Dogs present great similarities with humans, including in cases of central nervous system pathologies. The paper presents the first study on healthy dog cerebrospinal fluid metabolomic profile using 1H NMR spectroscopy. A number of 13 metabolites have been identified and quantified from cerebrospinal fluid collected from a group of 10 mix breed healthy dogs. The biological variability as resulting from the relative standard deviation of the physiological concentrations of the identified metabolites had a mean of 18.20% (range between 9.3% and 44.8%). The reported concentrations for metabolites may be used as normal reference values. The homogeneity of the obtained results and the low biologic variability show that the 1H NMR analysis of the dog’s cerebrospinal fluid is reliable in designing and interpreting clinical and therapeutic trials in dogs with central nervous system pathologies. PMID:24376499

2. 23Na and 1H NMR Microimaging of Intact Plants

Olt, Silvia; Krötz, Eva; Komor, Ewald; Rokitta, Markus; Haase, Axel

2000-06-01

23Na NMR microimaging is described to map, for the first time, the sodium distribution in living plants. As an example, the response of 6-day-old seedlings of Ricinus communis to exposure to sodium chloride concentrations from 5 to 300 mM was observed in vivo using 23Na as well as 1H NMR microimaging. Experiments were performed at 11.75 T with a double resonant 23Na-1H probehead. The probehead was homebuilt and equipped with a climate chamber. T1 and T2 of 23Na were measured in the cross section of the hypocotyl. Within 85 min 23Na images with an in-plane resolution of 156 × 156 μm were acquired. With this spatial information, the different types of tissue in the hypocotyl can be discerned. The measurement time appears to be short compared to the time scale of sodium uptake and accumulation in the plant so that the kinetics of salt stress can be followed. In conclusion, 23Na NMR microimaging promises great potential for physiological studies of the consequences of salt stress on the macroscopic level and thus may become a unique tool for characterizing plants with respect to salt tolerance and salt sensitivity.

3. 23Na and (1)H NMR microimaging of intact plants.

PubMed

Olt, S; Krötz, E; Komor, E; Rokitta, M; Haase, A

2000-06-01

(23)Na NMR microimaging is described to map, for the first time, the sodium distribution in living plants. As an example, the response of 6-day-old seedlings of Ricinus communis to exposure to sodium chloride concentrations from 5 to 300 mM was observed in vivo using (23)Na as well as (1)H NMR microimaging. Experiments were performed at 11.75 T with a double resonant (23)Na-(1)H probehead. The probehead was homebuilt and equipped with a climate chamber. T(1) and T(2) of (23)Na were measured in the cross section of the hypocotyl. Within 85 min (23)Na images with an in-plane resolution of 156 x 156 micrometer were acquired. With this spatial information, the different types of tissue in the hypocotyl can be discerned. The measurement time appears to be short compared to the time scale of sodium uptake and accumulation in the plant so that the kinetics of salt stress can be followed. In conclusion, (23)Na NMR microimaging promises great potential for physiological studies of the consequences of salt stress on the macroscopic level and thus may become a unique tool for characterizing plants with respect to salt tolerance and salt sensitivity.

4. Metabolomic insight into soy sauce through (1)H NMR spectroscopy.

PubMed

Ko, Bong-Kuk; Ahn, Hyuk-Jin; van den Berg, Frans; Lee, Cherl-Ho; Hong, Young-Shick

2009-08-12

Soy sauce, a well-known seasoning in Asia and throughout the world, consists of many metabolites that are produced during fermentation or aging and that have various health benefits. However, their comprehensive assessment has been limited due to targeted or instrumentally specific analysis. This paper presents for the first time a metabolic characterization of soy sauce, especially that aged up to 12 years, to obtain a global understanding of the metabolic variations through (1)H NMR spectroscopy coupled with multivariate pattern recognition techniques. Elevated amino acids and organic acids and the consumption of carbohydrate were associated with continuous involvement of microflora in aging for 12 years. In particular, continuous increases in the levels of betaine were found during aging for up to 12 years, demonstrating that microbial- or enzyme-related metabolites were also coupled with osmotolerant or halophilic bacteria present during aging. This work provides global insights into soy sauce through a (1)H NMR-based metabolomic approach that enhances the current understanding of the holistic metabolome and allows assessment of soy sauce quality.

5. The effect of delta9-tetrahydrocannabinol on the conversion of [3H]trypotphan to 5-[3H] hydroxytryptamine in the mouse brain.

PubMed

Johnson, K M; Dewey, W L

1978-10-01

The effects of a 30-min pretreatment with varying doses of delta9-tetrahydrocannibinol (delta9-THC) on the synthesis of 5-[3H]hydroxytryptamine (5-[3H]HT) from an intravenous 10-min pulse of L-[3H]tryptophan ([3H]try) were measured in the mouse brain. We also determined the effects of delta9-THC on several parameters believed to influence the synthesis of brain 5-HT, including total and free plasma tryptophan and the high-affinity synaptosomal uptake of tryptophan. Delta9-THC was found to increase the amount of [3H]try accumulated by the brain as well as the amount of 5-[3H]HT synthesized. This effect was greater at intermediate doses than at the highest dose tested. However, delta9-THC was determined to have no effect on the actual rate of conversion of [3H]try into 5-[3H]HT at any dose tested. Delta9-THC had no effect on either plasma tyrosine ot free tryptophan levels. However, delta9-THC decreased total plasma tryptophan at low and intermediate doses, but had no effect at the highest dose tested. Synaptosomal uptake of [3H]try was unaffected by pretreatment with delta9-THC at any dose tested. These data suggest that delta9-THC increases the synthesis of 5-HT, not by altering the actual rate of conversion of tryptophan to 5-HT, but by altering, via an unknown mechanism, the quantity of tryptophan available for conversion to 5-HT.

6. Nicotinic binding in rat brain: autoradiographic comparison of (/sup 3/H)acetylcholine, (/sup 3/H)nicotine, and (/sup 125/I)-alpha-bungarotoxin

SciTech Connect

Clarke, P.B.; Schwartz, R.D.; Paul, S.M.; Pert, C.B.; Pert, A.

1985-05-01

Three radioligands have been commonly used to label putative nicotinic cholinoceptors in the mammalian central nervous system: the agonists (/sup 3/H)nicotine and (/sup 3/H)acetylcholine ((/sup 3/H)ACh--in the presence of atropine to block muscarinic receptors), and the snake venom extract, (/sup 125/I)-alpha-bungarotoxin((/sup 125/I)BTX), which acts as a nicotinic antagonist at the neuromuscular junction. Binding studies employing brain homogenates indicate that the regional distributions of both (/sup 3/H)nicotine and (/sup 3/H)ACh differ from that of (/sup 125/I)BTX. The possible relationship between brain sites bound by (/sup 3/H)nicotine and (/sup 3/H)ACh has not been examined directly. The authors have used the technique of autoradiography to produce detailed maps of (/sup 3/H)nicotine, (/sup 3/H)ACh, and (/sup 125/I)BTX labeling; near-adjacent tissue sections were compared at many levels of the rat brain. The maps of high affinity agonist labeling are strikingly concordant, with highest densities in the interpeduncular nucleus, most thalamic nuclei, superior colliculus, medial habenula, presubiculum, cerebral cortex (layers I and III/IV), and the substantia nigra pars compacta/ventral tegmental area. The pattern of (/sup 125/I)BTX binding is strikingly different, the only notable overlap with agonist binding being the cerebral cortex (layer I) and superior colliculus. (/sup 125/I)BTX binding is also dense in the inferior colliculus, cerebral cortex (layer VI), hypothalamus, and hippocampus, but is virtually absent in thalamus. Various lines of evidence suggest that the high affinity agonist-binding sites in brain correspond to nicotinic cholinergic receptors similar to those found at autonomic ganglia; BTX-binding sites may also serve as receptors for nicotine and are possibly related to neuromuscular nicotinic cholinoceptors.

7. Silica gel-catalyzed one-pot syntheses in water and fluorescence properties studies of 5-amino-2-aryl-3H-chromeno[4,3,2-de][1,6]naphthyridine-4-carbonitriles and 5-amino-2-aryl-3H-quinolino[4,3,2-de][1,6]naphthyridine-4-carbonitriles.

PubMed

Wu, Hui; Lin, Wei; Wan, Yu; Xin, Hai-qiang; Shi, Da-qing; Shi, Yan-hui; Yuan, Rui; Bo, Rong-cheng; Yin, Wei

2010-01-01

The silica gel-catalyzed synthesis of 5-amino-2-aryl-3H-chromeno[4,3,2-de][1,6]naphthyridine-4-carbonitriles and 5-amino-2-aryl-3H-quinolino[4,3,2-de][1,6]naphthyridine-4-carbonitriles were simply achieved upon the one-pot cascade reaction of malononitrile with substituted 2-hydroxyacetophenone (or 2-aminoacetophenone) and aromatic aldehyde in aqueous media. The mechanistic investigation results based on electrospray ionization mass spectrometry (ESI-MS) indicated that malononitrile displayed a dual role during this transformation. Thirteen bonds were cleaved and 12 new bonds were constructed in the formation of 5-amino-2-aryl-3H-chromeno[4,3,2-de][1,6]naphthyridine-4-carbonitriles, while only 2 H(2)O molecules were removed. The fluorescence properties screening showed five new compounds have high fluorescence quantum yields.

8. High affinity binding of [3H]-tyramine in the central nervous system.

PubMed Central

Vaccari, A.

1986-01-01

Optimum assay conditions for the association of [3H]-para-tyramine [( 3H]-pTA) with rat brain membranes were characterized, and a saturable, reversible, drug-specific, and high affinity binding mechanism for this trace amine was revealed. The binding capacity (Bmax) for [3H]-pTA in the corpus striatum was approximately 30 times higher than that in the cerebellum, with similar dissociation constants (KD). The binding process of [3H]-pTA involved the dopamine system, inasmuch as (a) highest binding capacity was associated with dopamine-rich regions; (b) dopamine and pTA equally displaced specifically bound [3H]-pTA; (c) there was a severe loss in striatal binding capacity for [3H]-pTA and, reportedly, for [3H]-dopamine, following unilateral nigrostriatal lesion; (d) acute in vivo reserpine treatment markedly decreased the density of [3H]-pTA and, reportedly, of [3H]-dopamine binding sites. In competition experiments [3H]-pTA binding sites, though displaying nanomolar affinity for dopamine, revealed micromolar affinities for the dopamine agonists apomorphine and pergolide, and for several dopamine antagonists, while having very high affinity for reserpine, a marker for the catecholamine transporter in synaptic vesicles. The binding process of [3H]-pTA was both energy-dependent (ouabain-sensitive), and ATP-Mg2+-insensitive; furthermore, the potencies of various drugs in competing for [3H]-pTA binding to rat striatal membranes correlated well (r = 0.96) with their reported potencies in inhibiting [3H]-dopamine uptake into striatal synaptosomes. It is concluded that [3H]-pTA binds at a site located on/within synaptic vesicles where it is involved in the transport mechanism of dopamine. PMID:3801770

9. CN and C2H in IRC +10216

NASA Technical Reports Server (NTRS)

Huggins, P. J.; Glassgold, A. E.; Morris, M.

1984-01-01

The effects of the production of the radicals CN and C2H from the dissociation of HCN and C2H2 by ambient UV photons in the outer envelope of IRC +10216 are investigated. The spatial distribution of the radicals and their observable millimeter emission-line characteristics are calculated from the inferred abundances of the progenitor species in the envelope of IRC +10216 using photochemical and radiative transfer models. These are compared with available observations to examine whether photoproduction is a possible explanation of the observed emission from these species. The results suggest that the variable abundances induced by photodestruction of their progenitors do affect the observed emission from the radicals.

10. Experimental cross-sections energy dependence and an ab initio electronic structure survey of the ground singlet potential surface for reactive Li(+) + n-C(3)H(7)Cl collisions at low energies.

PubMed

Lucas, José María; de Andrés, Jaime; Albertí, Margarita; Bofill, Josep Maria; Bassi, Davide; Aguilar, Antonio

2010-11-07

Reactive collisions between n-C(3)H(7)Cl molecules and lithium ions both in their ground electronic state have been studied in the 0.05-7.00 eV center of mass energy range using an octopole radio frequency guided-ion beam apparatus developed in our laboratory and recently modified. At low collision energies, dehydrohalogenation reactions leading to Li(C(3)H(6))(+) and Li(HCl)(+) are the main reaction channels, while on increasing energies C(3)H(7)(+) and C(2)H(3)(+) formation become dominant. Cross section energy dependences in arbitrary units for all these reactions have been measured. Also, ab initio electronic structure calculations at the MP2 level have been performed to obtain information about the potential energy surface on which the reactive processes take place. The reactants' entrance channel leads to the formation of a stable [Li-n-C(3)H(7)Cl](+) ion-molecule adduct that, following an intrinsic-reaction-coordinate pathway and surmounting a transition state, isomerizes to [Li-i-C(3)H(7)Cl](+). From this second minimum, dehydrohalogenation reactions for both n-C(3)H(7)Cl and i-C(3)H(7)Cl share a common reaction pathway leading to the same products. All potential barriers explored by reactions always lie below the reactants' energy. The entrance reaction channel [Li-n-C(3)H(7)Cl](+) adduct also leads adiabatically to C(3)H(7)(+) formation which, on increasing collision energy generates C(2)H(3)(+)via a unimolecular decomposition. A qualitative interpretation of the experimental results based on our ab initio calculations is also given.

11. Estimate of recharge of a rising water table in semiarid Niger from 3H and 14C modeling.

PubMed

Favreau, Guillaume; Leduc, Christian; Marlin, Christelle; Dray, Martial; Taupin, Jean-Denis; Massault, Marc; Le, GalLaSalleCorinne; Babic, Milanka

2002-01-01

A hydrodynamic survey carried out in semiarid southwest Niger revealed an increase in the unconfined ground water reserves of approximately 10% over the last 50 years due to the clearing of native vegetation. Isotopic samplings (3H, 18O, 2H for water and 14C, 13C for the dissolved inorganic carbon) were performed on about 3500 km2 of this silty aquifer to characterize recharge. Stable isotope analyses confirmed the indirect recharge process that had already been shown by hydrodynamic surveys and suggested the tracers are exclusively of atmospheric origin. An analytical model that takes into account the long-term rise in the water table was used to interpret 3H and 14C contents in ground water. The natural, preclearing median annual renewal rate (i.e., recharge as a fraction of the saturated aquifer volume) lies between 0.04% and 0.06%. For representative characteristics of the aquifer (30 m of saturated thickness, porosity between 10% and 25%), this implies a recharge of between 1 and 5 mm/year, which is much lower than the estimates of 20 to 50 mm/year for recent years, obtained using hydrological and hydrodynamic methods and the same aquifer parameters. Our study, therefore, reveals that land clearing in semiarid Niger increased ground water recharge by about one order of magnitude.

12. Synthesis and antifungal activity of 2H-1,4-benzoxazin-3(4H)-one derivatives.

PubMed

Śmist, Małgorzata; Kwiecień, Halina; Krawczyk, Maria

2016-01-01

A series of 2-alkyl-2H-1,4-benzoxazin-3(4H)-ones (4a-l) was easily synthesized by two-step process involving O-alkylation of 2-nitrophenols with methyl 2-bromoalkanoates and next "green" catalytic reductive cyclization of the obtained 2-nitro ester intermediates (3a-l). Further, 6,7-dibromo (5a-c) and N-acetyl (6) derivatives were prepared by bromination and acetylation of unsubstituted 2-alkyl-2H-1,4-benzoxazin-3(4H)-ones (4a-c). The novel compounds (3a-l, 4d-l, 5a-c and 6) were fully characterized by spectroscopic methods (MS, (1)H and (13)C NMR). 2-Alkyl-2H-1,4-benzoxazin-3(4H)-ones (4a-l, 5a-c and 6) were screened for antifungal activity. Preliminary assays were performed using two methods: in vitro against seven phytopathogenic fungi-Botrytis cinerea, Phythophtora cactorum, Rhizoctonia solani, Phoma betae, Fusarium culmorum, Fusarium oxysporum and Alternaria alternata-and in vivo against barley powdery mildew Blumeria graminis. The tested compounds displayed moderate to good antifungal activity at high concentration (200 mg L(-1)). The most potent compounds were 2-ethyl-2H-1,4-benzoxazin-3(4H)-one (4a), 2-ethyl-7-fluoro-2H-1,4-benzoxazin-3(4H)-one (4g) and 4-acetyl-2-ethyl-2H-1,4-benzoxazin-3(4H)-one (6), which completely inhibited the mycelial growth of seven agricultural fungi at the concentration of 200 mg L(-1) in the in vitro tests. Moreover, 2-ethyl-2H-1,4-benzoxazin-3(4H)-one (4a) and 4-acetyl-2-ethyl-2H-1,4-benzoxazin-3(4H)-one (6) were also screened for antifungal activity at concentrations of 100 mg L(-1) and 20 mg L(-1). In the concentration of 100 mg L(-1), the N-acetyl derivative (6) completely inhibited the growth of three strains of fungi (F. culmorum, P. cactorum and R. solani), while 2-ethyl-2H-1,4-benzoxazin-3(4H)-one (4a) completely inhibited only R. solani strain. At the concentration of 20 mg L(-1), compound 6 showed good activity only against P. cactorum strain (72%).

13. Muon spin relaxation study of Zr(H2PO4)(PO4).2H2O.

PubMed

Clayden, Nigel J; Cottrell, Stephen P

2006-07-14

Muon spin relaxation has been used to study the muon dynamics in the layered zirconium phosphate Zr(H(2)PO(4))(PO(4)).2H(2)O as a function of temperature. Radiofrequency decoupling was used to establish the origin of the local dipolar field as coupling with (1)H spins. Muons were trapped at two sites, one identified as HMuO and the other consistent with PO-Mu on the basis of their zero-field second moments. Although a small decrease in the local nuclear dipolar field was seen with temperature, the muons remained essentially static over the temperature range 20-300 K.

14. Genetic Variation in Myosin 1H Contributes to Mandibular Prognathism

PubMed Central

Tassopoulou-Fishell, Maria; Deeley, Kathleen; Harvey, Erika M.; Sciote, James; Vieira, Alexandre R.

2013-01-01

Introduction Several candidate loci have been suggested as influencing mandibular prognathism (1p22.1, 1p22.2, 1p36, 3q26.2, 5p13-p12, 6q25, 11q22.2-q22.3, 12q23, 12q13.13, and 19p13.2). The goal of this study was to replicate these results in a well-characterized homogeneous sample set. Methods Thirty-three single nucleotide polymorphisms spanning all candidate regions were studied in 44 prognathic and 35 Class I subjects from the University of Pittsburgh School of Dental Medicine Dental Registry and DNA Repository. The 44 mandibular prognathism subjects had an average age of 18.4 years, 31 were females and 13 males, and 24 were White, 15 African American, two Hispanic, and three Asian. The 35 Class I subjects had an average age of 17.6 years, 27 were females and 9 males, and 27 were White, six African Americans, one Hispanic, and two Asian. Skeletal mandibular prognathism diagnosis included cephalometric values indicative of Class III such as ANB smaller than two degrees, negative Witts appraisal, and positive A–B plane. Additional mandibular prognathism criteria included negative OJ and visually prognathic (concave) profile as determined by the subject's clinical evaluation. Orthognathic subjects without jaw deformations were used as a comparison group. Mandibular prognathism and orthognathic subjects were matched based on race, sex and age. Genetic markers were tested by polymerase chain reaction using TaqMan chemistry. Chi-square and Fisher exact tests were used to determine overrepresentation of marker allele with alpha of 0.05. Results An association was unveiled between a marker in MYO1H (rs10850110) and the mandibular prognathism phenotype (p=0.03). MYO1H is a Class-I myosin that is in a different protein group than the myosin isoforms of muscle sarcomeres, which are the basis of skeletal muscle fiber typing. Class I myosins are necessary for cell motility, phagocytosis and vesicle transport. Conclusions More strict clinical definitions may increase

15. Synthesis ofN-(2-chloro-5-methylthiophenyl)-N'-(3-methyl-thiophenyl)-N'-[3H3]methylguanidine, l brace [3H3]CNS-5161 r brace

SciTech Connect

Gibbs, Andrew R.; Morimoto, Hiromi; VanBrocklin, Henry F.; Williams, Philip G.; Biegon, Anat

2001-09-28

The preparation of the title compound, [{sup 3}H{sub 3}]CNS-5161, was accomplished in three steps starting with the production of [{sup 3}H{sub 3}]iodomethane (CT{sub 3}I). The intermediate N-[{sup 3}H{sub 3}]methyl-3-(thiomethylphenyl)cyanamide was prepared in 77% yield by the addition of CT{sub 3}I to 3-(thiomethylphenyl)cyanamide, previously treated with sodium hydride. Reaction of this tritiated intermediate with 2-chloro-5-thiomethylaniline hydrochloride formed the guanidine compound [{sup 3}H{sub 3}]CNS-5161. Purification by HPLC gave the desired labeled product in an overall yield of 9% with greater than 96% radiochemical purity and a final specific activity of 66 Ci mmol{sup -1}.

16. Mechanisms of CO2/H+ Sensitivity of Astrocytes

PubMed Central

Turovsky, Egor; Theparambil, Shefeeq M.; Kasymov, Vitaliy; Deitmer, Joachim W.; del Arroyo, Ana Gutierrez; Ackland, Gareth L.; Corneveaux, Jason J.; Allen, April N.; Huentelman, Matthew J.; Kasparov, Sergey; Marina, Nephtali

2016-01-01

Ventral regions of the medulla oblongata of the brainstem are populated by astrocytes sensitive to physiological changes in PCO2/[H+]. These astrocytes respond to decreases in pH with elevations in intracellular Ca2+ and facilitated exocytosis of ATP-containing vesicles. Released ATP propagates Ca2+ excitation among neighboring astrocytes and activates neurons of the brainstem respiratory network triggering adaptive increases in breathing. The mechanisms linking increases in extracellular and/or intracellular PCO2/[H+] with Ca2+ responses in chemosensitive astrocytes remain unknown. Fluorescent imaging of changes in [Na+]i and/or [Ca2+]i in individual astrocytes was performed in organotypic brainstem slice cultures and acute brainstem slices of adult rats. It was found that astroglial [Ca2+]i responses triggered by decreases in pH are preceded by Na+ entry, markedly reduced by inhibition of Na+/HCO3− cotransport (NBC) or Na+/Ca2+ exchange (NCX), and abolished in Na+-free medium or by combined NBC/NCX blockade. Acidification-induced [Ca2+]i responses were also dramatically reduced in brainstem astrocytes of mice deficient in the electrogenic Na+/HCO3− cotransporter NBCe1. Sensitivity of astrocytes to changes in pH was not affected by inhibition of Na+/H+ exchange or blockade of phospholipase C. These results suggest that in pH-sensitive astrocytes, acidification activates NBCe1, which brings Na+ inside the cell. Raising [Na+]i activates NCX to operate in a reverse mode, leading to Ca2+ entry followed by activation of downstream signaling pathways. Coupled NBC and NCX activities are, therefore, suggested to be responsible for functional CO2/H+ sensitivity of astrocytes that contribute to homeostatic regulation of brain parenchymal pH and control of breathing. SIGNIFICANCE STATEMENT Brainstem astrocytes detect physiological changes in pH, activate neurons of the neighboring respiratory network, and contribute to the development of adaptive respiratory responses to

17. Crystal structure of 1H,1'H-[2,2'-biimid-azol]-3-ium hydrogen tartrate hemi-hydrate.

PubMed

Gao, Xiao-Li; Bian, Li-Fang; Guo, Shao-Wei

2014-11-01

In the crystal of the title hydrated salt, C6H7N4 (+)·C4H5O6 (-)·0.5H2O, the bi-imidazole monocation, 1H,1'H-[2,2'-biimidazol]-3-ium, is hydrogen bonded, via N-H⋯O, O-H⋯O and O-H⋯N hydrogen bonds, to the hydrogen tartrate anion and the water mol-ecule, which is located on a twofold rotation axis, forming sheets parallel to (001). The sheets are linked via C-H⋯O hydrogen bonds, forming a three-dimensional structure. There are also C=O⋯π inter-actions present [O⋯π distances are 3.00 (9) and 3.21 (7) Å], involving the carbonyl O atoms and the imidazolium ring, which may help to consolidate the structure. In the cation, the dihedral angle between the rings is 11.6 (2)°.

18. Measurement of regional cerebral blood flow in cat brain using intracarotid 2H2O and 2H NMR imaging

SciTech Connect

Detre, J.A.; Subramanian, V.H.; Mitchell, M.D.; Smith, D.S.; Kobayashi, A.; Zaman, A.; Leigh, J.S. Jr. )

1990-05-01

Cerebral blood flow (CBF) was measured in cat brain in vivo at 2.7 T using 2H NMR to monitor the washout of deuterated saline injected into both carotid arteries via the lingual arteries. In anesthetized cats, global CBF varied directly with PaCO{sub 2} over a range of 20-50 mm Hg, and the corresponding global CBF values ranged from 25 to 125 ml.100 g-1.min-1. Regional CBF was measured in a 1-cm axial section of cat brain using intracarotid deuterated saline and gradient-echo 2H NMR imaging. Blood flow images with a maximum pixel resolution of 0.3 x 0.3 x 1.0 cm were generated from the deuterium signal washout at each pixel. Image derived values for CBF agreed well with other determinations, and decreased significantly with hypocapnia.

19. Hydrogenation and Deuteration of C2H2 and C2H4 on Cold Grains: A Clue to the Formation Mechanism of C2H6 with Astronomical Interest

Kobayashi, Hitomi; Hidaka, Hiroshi; Lamberts, Thanja; Hama, Tetsuya; Kawakita, Hideyo; Kästner, Johannes; Watanabe, Naoki

2017-03-01

We quantitatively investigated the hydrogen addition reactions of acetylene (C2H2) and ethylene (C2H4) on amorphous solid water (ASW) at 10 and 20 K relevant to the formation of ethane (C2H6) on interstellar icy grains. We found that the ASW surface enhances the reaction rates for C2H2 and C2H4 by approximately a factor of 2 compared to those on the pure-solid C2H2 and C2H4 at 10 K, probably due to an increase in the sticking coefficient and adsorption energy of the H atoms on ASW. In contrast to the previous proposal that the hydrogenation rate of C2H4 is orders of magnitude larger than that of C2H2, the present results show that the difference in hydrogenation rates of C2H2 and C2H4 is only within a factor of 3 on both the surfaces of pure solids and ASW. In addition, we found the small kinetic isotope effect for hydrogenation/deuteration of C2H2 and C2H4 at 10 K, despite the requirement of quantum tunneling. At 20 K, the reaction rate of deuteration becomes even larger than that of hydrogenation. These unusual isotope effects might originate from a slightly larger number density of D atoms than H atoms on ASW at 20 K. The hydrogenation of C2H2 is four times faster than CO hydrogenation and can produce C2H6 efficiently through C2H4 even in the environment of a dark molecular cloud.

20. Theoretical study on the rate constants for the C2H5 + HBr --> C2H6 + Br reaction.

PubMed

Sheng, Li; Li, Ze-Sheng; Liu, Jing-Yao; Xiao, Jing-Fa; Sun, Chia-Chung

2004-02-01

The reaction C(2)H(5) + HBr --> C(2)H(6) + Br has been theoretically studied over the temperature range from 200 to 1400 K. The electronic structure information is calculated at the BHLYP/6-311+G(d,p) and QCISD/6-31+G(d) levels. With the aid of intrinsic reaction coordinate theory, the minimum energy paths (MEPs) are obtained at the both levels, and the energies along the MEP are further refined by performing the single-point calculations at the PMP4(SDTQ)/6-311+G(3df,2p)//BHLYP and QCISD(T)/6-311++G(2df,2pd)//QCISD levels. The calculated ICVT/SCT rate constants are in good agreement with available experimental values, and the calculate results further indicate that the C(2)H(5) + HBr reaction has negative temperature dependence at T < 850 K, but clearly shows positive temperature dependence at T > 850 K. The current work predicts that the kinetic isotope effect for the title reaction is inverse in the temperature range from 200 to 482 K, i.e., k(HBr)/k(DBr) < 1.

1. Characterization of (/sup 3/H)pirenzepine binding to muscarinic cholinergic receptors solubilized from rat brain

SciTech Connect

Luthin, G.R.; Wolfe, B.B.

1985-07-01

Membranes prepared from rat cerebral cortex were solubilized in buffer containing 1% digitonin. Material present in the supernatant after centrifugation at 147,000 X g was shown to contain binding sites for both (/sup 3/H)quinuclidinyl benzilate ((/sup 3/H)QNB) and (/sup 3/H)pirenzepine ((/sup 3/H)PZ). Recovery of binding sites was approximately 25% of the initial membrane-bound (/sup 3/H)QNB binding sites. The Kd values for (/sup 3/H)QNB and (/sup 3/H)PZ binding to solubilized receptors were 0.3 nM and 0.1 microM, respectively. As has been observed previously in membrane preparations, (/sup 3/H)PZ appeared to label fewer solubilized binding sites than did (/sup 3/H)QNB. Maximum binding values for (/sup 3/H)PZ and (/sup 3/H)QNB binding to solubilized receptors were approximately 400 and 950 fmol/mg of protein, respectively. Competition curves for PZ inhibiting the binding of (/sup 3/H)QNB, however, had Hill slopes of 1, with a Ki value of 0.24 microM. The k1 and k-1 for (/sup 3/H)PZ binding were 3.5 X 10(6) M-1 min-1 and 0.13 min-1, respectively. The muscarinic receptor antagonists atropine, scopolamine and PZ inhibited the binding of (/sup 3/H)QNB and (/sup 3/H)PZ to solubilized receptors with Hill slopes of 1, as did the muscarinic receptor agonist oxotremorine. The muscarinic receptor agonist carbachol competed for (/sup 3/H)QNB and (/sup 3/H)PZ binding with a Hill slope of less than 1 in cerebral cortex, but not in cerebellum. GTP did not alter the interactions of carbachol or oxotremorine with the solubilized receptor. Together, these data suggest that muscarinic receptor sites solubilized from rat brain retain their abilities to interact selectively with muscarinic receptor agonists and antagonists.

2. Thermodynamic properties and crystal structure refinement of ferricopiapite, coquimbite, rhomboclase, and Fe2(SO4)3(H2O)5

USGS Publications Warehouse

Majzlan, J.; Navrotsky, A.; McCleskey, R.B.; Alpers, C.N.

2006-01-01

Enthalpies of formation of ferricopiapite [nominally Fe4.67(SO4)6(OH)2 (H2O)20]. coquimbite [Fe2(SO4)3(H2O)9], rhomboclase [(H3O)Fe(SO4)2 (H2O)3], and Fe2(SO4)3(H2O)5 were measured by acid (5 N HCl) solution calorimetry. The samples were characterized by wet chemical analyses and synchrotron powder X-ray diffraction (XRD). The refinement of XRD patterns gave lattice parameters, atomic positions, thermal factors, and occupancies of the sites. The calculated formulae differ slightly from the nominal compositions: Fe4.78(SO4)6 (OH)2.34(H2O)20.71 (ferricopiapite), (Fe1.47Al0.53)(SO4)3 (H2O)9.65 (coquimbite), (H3O)1.34Fe(SO4)2.17 (H2O)3.06 (rhomboclase), and Fe2(SO4)3 (H2O)5.03. All thermodynamic data are given per mole of these formulae. The measured standard enthalpies (in kJ/mol) of formation from the elements (crystalline Fe, Al, S, and ideal gases O2 and H2) at T = 298.15 K are -4115.8??4.1 [Fe2(SO4)3 (H2O)5.03], -12045.1??9.2 (ferricopiapite), -5738.4??3.3 (coquimbite), and -3201.1??2.6 (rhomboclase). Standard entropy (S??) was estimated as a sum of entropies of oxide, hydroxide, and sulfate components. The estimated S?? (in J/mol.K) values for the iron sulfates are 488.2 [Fe2(SO4)3 (H2O)5.03], 1449.2 (ferricopiapite), 638.3 (coquimbite), and 380.1 (rhomboclase). The calculated Gibbs free energies of formation (in kJ/mol) are -3499.7??4.2 [Fe2(SO4)3 (H2O)5.03], -10089.8??9.3 (ferricopiapite), -4845.6??3.3 (coquimbite), and -2688.0??2.7 (rhomboclase). These results combined with other available thermodynamic data allow construction of mineral stability diagrams in the FeIII2(SO4)3-FeII SO4-H2O system. One such diagram is provided, indicating that the order of stability of ferric sulfate minerals with decreasing pH in the range of 1.5 to -0.5 is: hydronium jarosite, ferricopiapite, and rhomboclase. ?? 2006 E. Schweizerbart'sche Verlagsbuchhandlung.

3. Theoretical kinetics of O + C2H4

DOE PAGES

Li, Xiaohu; Jasper, Ahren W.; Zádor, Judit; ...

2016-06-01

The reaction of atomic oxygen with ethylene is a fundamental oxidation step in combustion and is prototypical of reactions in which oxygen adds to double bonds. For 3O+C2H4 and for this class of reactions generally, decomposition of the initial adduct via spin-allowed reaction channels on the triplet surface competes with intersystem crossing (ISC) and a set of spin-forbidden reaction channels on the ground-state singlet surface. The two surfaces share some bimolecular products but feature different intermediates, pathways, and transition states. In addition, the overall product branching is therefore a sensitive function of the ISC rate. The 3O+C2H4 reaction has beenmore » extensively studied, but previous experimental work has not provided detailed branching information at elevated temperatures, while previous theoretical studies have employed empirical treatments of ISC. Here we predict the kinetics of 3O+C2H4 using an ab initio transition state theory based master equation (AITSTME) approach that includes an a priori description of ISC. Specifically, the ISC rate is calculated using Landau–Zener statistical theory, consideration of the four lowest-energy electronic states, and a direct classical trajectory study of the product branching immediately after ISC. The present theoretical results are largely in good agreement with existing low-temperature experimental kinetics and molecular beam studies. Good agreement is also found with past theoretical work, with the notable exception of the predicted product branching at elevated temperatures. Above ~1000 K, we predict CH2CHO+H and CH2+CH2O as the major products, which differs from the room temperature preference for CH3+HCO (which is assumed to remain at higher temperatures in some models) and from the prediction of a previous detailed master equation study.« less

4. Mechanisms of CO2/H+ Sensitivity of Astrocytes.

PubMed

Turovsky, Egor; Theparambil, Shefeeq M; Kasymov, Vitaliy; Deitmer, Joachim W; Del Arroyo, Ana Gutierrez; Ackland, Gareth L; Corneveaux, Jason J; Allen, April N; Huentelman, Matthew J; Kasparov, Sergey; Marina, Nephtali; Gourine, Alexander V

2016-10-19

Ventral regions of the medulla oblongata of the brainstem are populated by astrocytes sensitive to physiological changes in PCO2/[H(+)]. These astrocytes respond to decreases in pH with elevations in intracellular Ca(2+) and facilitated exocytosis of ATP-containing vesicles. Released ATP propagates Ca(2+) excitation among neighboring astrocytes and activates neurons of the brainstem respiratory network triggering adaptive increases in breathing. The mechanisms linking increases in extracellular and/or intracellular PCO2/[H(+)] with Ca(2+) responses in chemosensitive astrocytes remain unknown. Fluorescent imaging of changes in [Na(+)]i and/or [Ca(2+)]i in individual astrocytes was performed in organotypic brainstem slice cultures and acute brainstem slices of adult rats. It was found that astroglial [Ca(2+)]i responses triggered by decreases in pH are preceded by Na(+) entry, markedly reduced by inhibition of Na(+)/HCO3(-) cotransport (NBC) or Na(+)/Ca(2+) exchange (NCX), and abolished in Na(+)-free medium or by combined NBC/NCX blockade. Acidification-induced [Ca(2+)]i responses were also dramatically reduced in brainstem astrocytes of mice deficient in the electrogenic Na(+)/HCO3(-) cotransporter NBCe1. Sensitivity of astrocytes to changes in pH was not affected by inhibition of Na(+)/H(+) exchange or blockade of phospholipase C. These results suggest that in pH-sensitive astrocytes, acidification activates NBCe1, which brings Na(+) inside the cell. Raising [Na(+)]i activates NCX to operate in a reverse mode, leading to Ca(2+) entry followed by activation of downstream signaling pathways. Coupled NBC and NCX activities are, therefore, suggested to be responsible for functional CO2/H(+) sensitivity of astrocytes that contribute to homeostatic regulation of brain parenchymal pH and control of breathing.

5. Study of morphology of aerosol aggregates formed during co-pyrolysis of C3H8 + Fe(CO)5

Ivanova, N. A.; Onischuk, A. A.; di Stasio, S.; Baklanov, A. M.; Makhov, G. A.

2007-04-01

Formation of aerosol nanoparticles as well as carbon nanotubes and nanofilaments is studied during co-pyrolysis of iron pentacarbonyl and propane with argon as a carrier gas in a flow reactor. Gaseous intermediates from propane thermal decomposition (CH4, C2H6 and C3H4) and Fe(CO)5 conversion are monitored by gas chromatography and IR-spectroscopy, respectively. The aerosol morphology is studied by transmission electron microscopy (TEM) and high resolution TEM. The aerosol particle concentration and size distribution are measured by an automated diffusion battery. The crystal phase composition of particles is studied by x-ray diffractometry. The decomposition of the Fe(CO)5 + Ar mixture resulted in an iron aggregate formation composed of fine primary particles. In the case of lower pyrolysis temperatures, about 450 K, the primary particle mean diameter is about 10 nm, and consequently, the majority of the primary particles are superparamagnetic, thus forming compact aggregates. At intermediate pyrolysis temperatures in the range 800-1040 K the primary particle diameter is about 20-30 nm, and most of the particles are ferromagnetic in nature. The coagulation of these particles results in a chain-like aggregate formation. Finally, at temperatures higher than the Curie point (1043 K) the ferromagnetic properties vanish and the formation of compact aggregates is observed again. The co-pyrolysis of Fe(CO)5 and C3H8 mixed with Ar carrier gas resulted in aerosol aggregate structures dramatically different from those formed by iron pentacarbonyl pyrolysis. In particular, in the temperature range 1070-1280 K, we observed Fe3C particles connected by long carbon nanotubes (CNTs). The aggregate morphology is described in terms of a fractal-like dimension Df, which is determined from TEM images on the basis of a scaling power law linking the aggregate mass (M) and radius (R), M{\\sim}R^{D_f} . The Fe3C-CNT aggregate morphology is a function of the inlet ratio between propane

6. Synthesis of 2H- and 13C-substituted dithanes

DOEpatents

Martinez, Rodolfo A.; Alvarez, Marc A.; Silks, III, Louis A.; Unkefer, Clifford J.

2003-01-01

The present invention is directed to labeled compounds, [2-.sup.13 C]dithiane wherein the .sup.13 C atom is directly bonded to one or two deuterium atoms. The present invention is also directed to processes of preparing [2-.sup.13 C]dithiane wherein the .sup.13 C atom is directly bonded to one or two deuterium atoms. The present invention is also directed to labeled compounds, e.g., [.sup.2 H.sub.1-2, .sup.13 C]methanol (arylthio)-, acetates wherein the .sup.13 C atom is directly bonded to exactly one or two deuterium atoms.

7. Synthesis Of 2h- And 13c-Substituted Dithanes

DOEpatents

Martinez, Rodolfo A.; Alvarez, Marc A.; Silks, III, Louis A.; Unkefer, Clifford J.

2004-05-04

The present invention is directed to labeled compounds, [2-.sup.13 C]dithane wherein the .sup.13 C atom is directly bonded to one or two deuterium atoms. The present invention is also directed to processes of preparing [2-.sup.13 C]dithane wherein the .sup.13 C atom is directly bonded to one or two deuterium atoms. The present invention is also directed to labeled compounds, e.g., [.sup.2 H.sub.1-2, .sup.13 C]methanol (arylthio)-, acetates wherein the .sup.13 C atom is directly bonded to exactly one or two deuterium atoms.

8. Endocytic pathway for /sup 3/H-histamine (/sup 3/H-HIS) metabolism in cultured human vascular endothelial cells (HEC)

SciTech Connect

Haddock, R.C.; Mack, P.; Baenziger, N.L.

1986-03-01

Histamine metabolism by HEC utilizes enzymes from both endogenous and extracellular sources. HEC convert histamine to tele-methyl-histamine and accumulate this product. They exhibit a 6- to 10-fold enhancement of /sup 3/H-HIS uptake by exogenous amine oxidase activity from human placenta (P-AO) or fetal calf serum (FCS-AO) and accumulate methyl-imidazole-acetic acid (MIAA). /sup 3/H-HIS uptake is saturable with respect to /sup 3/H-HIS and to P-AO or FCS-AO, suggesting a limited number of interaction sites on HEC. Half maximal and saturated uptake occur at 1.6 ..mu..M and 4 ..mu..M for /sup 3/H-HIS, at 0.14 U/ml and 0.65 U/ml for P-AO, and 1.0- U/ml and 2.0 U/ml for FCS-AO (1 U/ml = 1 nmole putrescine degraded/hour). FCS-AO-enhanced uptake is inhibited 64% to 94% by 3-30 mM methylmaine and 98% by 75 ..mu..M chloroquine. Treatment of HEC with dextran sulfate removes bound FCS-AO activity, blocking subsequent /sup 3/H-HIS uptake by 84%. /sup 3/H-HIS-derived metabolites present in the plasma membrane fraction of HEC incubated in the absence or presence of FCS-AO activity, are tele-methyl-histamine or MIAA respectively. These results suggest the involvement of an endocytic-type process in /sup 3/H-HIS uptake and degradation, utilizing membrane-associated endogenous and exogenous enzymes.

9. Modulation of [3H]diazepam binding in rat cortical membranes by GABAA agonists.

PubMed

Wong, E H; Iversen, L L

1985-04-01

GABAA receptor agonists modulate [3H]diazepam binding in rat cortical membranes with different efficacies. At 23 degrees C, the relative potencies for enhancement of [3H]diazepam binding by agonists parallel their potencies in inhibiting [3H]gamma-aminobutyric acid [( 3H]GABA) binding. The agonist concentrations needed for enhancement of [3H]diazepam binding are up to 35 times higher than for [3H]GABA binding and correspond closely to the concentrations required for displacement of [3H]bicuculline methochloride (BMC) binding. The maximum enhancement of [3H]diazepam varied among agonists: muscimol = GABA greater than isoguvacine greater than 3-aminopropane sulphonic acid (3APS) = imidazoleacetic acid (IAA) greater than 4,5,6,7-tetrahydroisoxazolo (4,5,6)-pyridin-3-ol (THIP) = taurine greater than piperidine 4-sulphonic acid (P4S). At 37 degrees C, the potencies of agonists remained unchanged, but isoguvacine, 3 APS, and THIP acquired efficacies similar to GABA, whereas IAA, taurine, and P4S maintained their partial agonist profiles. At both temperatures the agonist-induced enhancement of [3H]diazepam binding was reversible by bicuculline methobromide and by the steroid GABA antagonist RU 5135. These results stress the importance of studying receptor-receptor interaction under near-physiological conditions and offer an in vitro assay that may predict the agonist status of putative GABA receptor ligands.

10. Liver Metabolite Concentrations Measured with 1H MR Spectroscopy

PubMed Central

Pettigrew, Roderic I.; Gharib, Ahmed M.

2012-01-01

Purpose: To determine the feasibility of measuring choline and glycogen concentrations in normal human liver in vivo with proton (hydrogen 1 [1H]) magnetic resonance (MR) spectroscopy. Materials and Methods: Signed consent to participate in an institutional review board–approved and HIPAA-compliant study was obtained from 46 subjects (mean age, 46 years ± 17 [standard deviation]; 24 women) consecutively recruited during 285 days. Navigator-gated MR images were used to select 8-mL volumes for point-resolved spectroscopy (PRESS) with a 35-msec echo time. Line widths were minimized with fast breath-hold B0 field mapping and further manual shimming. Navigator-gated spectra were recorded with and without water suppression to determine metabolite concentrations with water signals as an internal reference. In three subjects, echo time was varied to determine the glycogen and choline T2. Linear regression analysis was used to examine relations between choline, hepatic lipid content, body mass index, glycogen content, and age. Results: Choline concentrations could be determined in 46 of 48 studies and was found to be 8.6 mmol per kilogram of wet weight ± 3.1 (range, 3.8–17.6; n = 44). Twenty-seven spectra in 25 individuals with narrow line widths and low lipid content were adequate for quantitation of glycogen. The glycogen (glucosyl unit) concentration was 38.1 mmol/kg wet weight ± 14.4. The T2 of combined glycogen peaks in the liver of three subjects was 36 msec ± 8. Choline levels showed a weak but significant correlation with glycogen (r2 = 0.15; P < .05) but not with lipid content. Conclusion: Navigator-gated and gradient-echo shimmed PRESS 1H MR spectroscopy may allow quantification of liver metabolites that are important for understanding and identifying disorders of glucose and lipid metabolism. © RSNA, 2012 Supplemental material: http://radiology.rsna.org/lookup/suppl/doi:10.1148/radiol.12112344/-/DC1 PMID:22891360

11. Hexamethyldisiloxane-based nanoprobes for (1) H MRI oximetry.

PubMed

Gulaka, Praveen K; Rastogi, Ujjawal; McKay, Madalyn A; Wang, Xianghui; Mason, Ralph P; Kodibagkar, Vikram D

2011-12-01

Quantitative in vivo oximetry has been reported using (19) F MRI in conjunction with reporter molecules, such as perfluorocarbons, for tissue oxygenation (pO(2) ). Recently, hexamethyldisiloxane (HMDSO) has been proposed as a promising alternative reporter molecule for (1) H MRI-based measurement of pO(2) . To aid biocompatibility for potential systemic administration, we prepared various nanoemulsion formulations using a wide range of HMDSO volume fractions and HMDSO to surfactant ratios. Calibration curves (R(1) versus pO(2) ) for all emulsion formulations were found to be linear and similar to neat HMDSO for low surfactant concentrations (<10% v/v). A small temperature dependence in the calibration curves was observed, similar to previous reports on neat HMDSO, and was characterized to be approximately 1 Torr/ °C under hypoxic conditions. To demonstrate application in vivo, 100 µL of this nanoemulsion was administered to healthy rat thigh muscle (Fisher 344, n=6). Dynamic changes in mean thigh tissue pO(2) were measured using the PISTOL (proton imaging of siloxanes to map tissue oxygenation levels) technique in response to oxygen challenge. Changing the inhaled gas to oxygen for 30 min increased the mean pO(2) significantly (p<0.001) from 39 ± 7 to 275 ± 27 Torr. When the breathing gas was switched back to air, the tissue pO(2) decreased to a mean value of 45 ± 6 Torr, not significantly different from baseline (p>0.05), in 25 min. A first-order exponential fit to this part of the pO(2) data (i.e. after oxygen challenge) yielded an oxygen consumption-related kinetic parameter k=0.21 ± 0.04 min(-1) . These results demonstrate the feasibility of using HMDSO nanoemulsions as nanoprobes of pO(2) and their utility to assess oxygen dynamics in vivo, further developing quantitative (1) H MRI oximetry.

12. Novel bipyridinyl oxadiazole-based metal coordination complexes: High efficient and green synthesis of 3,4-dihydropyrimidin-2(1H)-ones through the Biginelli reactions

Wang, Jin-Hua; Zhang, E.; Tang, Gui-Mei; Wang, Yong-Tao; Cui, Yue-Zhi; Ng, Seik Weng

2016-09-01

Three new metal coordination complexes, namely, [Co(BPO)2(H2O)4](BS)2(H2O)2 (1), [Co(BPO)2(H2O)4](ABS)2(H2O)2 (2), [Co(BPO)2(H2O)4](MBS)2(H2O)2 (3) [BPO=2,5-di(pyridin-4-yl)-1,3,4-oxadiazole, BS=benzenesulphonate, ABS=4-aminobenzenesulphonate, MBS=4-methylbenzenesulphonate] were obtained under hydrothermal conditions. Complexes 1-3 were structurally characterized by single-crystal X-ray diffraction, powder X-ray diffraction, IR and thermogravimetric analyses (TGA). All of them display a zero-dimensional motif, in which strong intermolecular hydrogen bonding interactions (O-H···O/N) and packing interactions (C-H···π and π···π) make them achieve a three-dimensional supramolecular architecture. The primary catalytic results of these three complexes show that high efficiency for the green synthesis of a variety of 3,4-dihydropyrimidin-2(1H)-ones was observed under solvent free conditions through Biginelli reactions. The present catalytic protocols exhibit advantages such as excellent yield, easy isolation, eco-friendly conditions, and short reaction time.

13. Correlation between catecholamine secretion from bovine isolated chromaffin cells and [3H]-ouabain binding to plasma membranes

PubMed Central

Aunis, Dominique; García, Antonio G.

1981-01-01

1 Secretion of catecholamines (CA) evoked by ouabain, chlormadinone acetate (CMA), phenoxybenzamine (Pbz) and vanadate, four agents known to inhibit Na+, K+-dependent Mg2+-activated adenosine triphosphatase (ATPase) activity has been studied in suspensions of bovine isolated adrenal medullary cells. 2 Acetylcholine (ACh) evoked a 5 fold increase of the basal CA secretion from isolated cells suspended in oxygenated Krebs-bicarbonate solution kept at 27°C. Secretion was antagonized by Ca2+-deprivation or hexamethonium, indicating good functional viability of the cells. 3 Ouabain (10-7 to 10-4 M) evoked a progressive, dose-dependent release of CA from cell suspensions. Study of the time course of the secretory response for 2 h allowed the separation of two components in the secretory response at all doses studied: a slow initial component (0.011 pg/min CA) and a second faster component (0.032 pg/min CA). 4 CMA evoked a clear-cut CA secretory response. The ED50 for CMA was 10-4 M, as compared to 3 × 10-6 M for ouabain. Pbz and vanadate did not induce CA release. 5 [3H]-ouabain was taken up and bound to intact isolated cells by a non-saturable binding process. However, in semi-purified plasma membranes from bovine adrenal medulla a saturable specific [3H]-ouabain binding process was observed with a KD of 8.1 nM. Binding to the membranes was ATP-dependent and antagonized by K+. 6 [3H]-ouabain specific binding to membranes was antagonized by ouabain and CMA, but not by Pbz or vanadate; the ID50 for ouabain and CMA were 10-6 and 10-5 M respectively. 7 Ouabain partially inhibited, in a dose-dependent manner, Na+, K+-Mg2+ ATPase activity of the semi-purified plasma membranes. 8 The results demonstrate a good correlation between the ability of different drugs, known to inhibit ATPase activity, to displace [3H]-ouabain binding to adreno—medullary plasma membranes and their capacity to evoke a CA secretory response from isolated chromaffin cells. The data also suggest that

14. Photodissociation spectroscopy of Ca+(C2H4)

Holmes, J. H.; Kleiber, P. D.; Olsgaard, D. A.; Yang, K.-H.

2000-04-01

We have studied Ca+(C2H4) by photodissociation spectroscopy in a reflectron time-of-flight mass spectrometer over the spectral range 440-790 nm. Ca+ is the only photofragment observed. We find four absorption bands of the complex and assign them to metal-centered transitions correlating with excitation of Ca+(3d and 4p). Spectral assignment is supported by ab initio electronic structure calculations of the complex and isotope substitution experiments. Calculations find a weakly bound ground state equilibrium structure with C2V π-bonding geometry and a dissociation energy of De″=0.506 eV. Theoretical and experimental results show the 4pπ(2 2B2 & 2 2B1) excited states to be relatively weakly bound at long range. Spectral analysis gives vibrational constants for the Ca+--C2H4 intermolecular a1-stretch in the 1 2A1, 2 2B1, and 2 2B2 states, and for the CH2-CH2 a1-wag and the HCH a1-bend in 2 2B2. The results offer an interesting comparison with previous studies of similar weakly bound bimolecular complexes of light metal ions with alkene or alkane hydrocarbons.

15. Mapping of prostate cancer by 1H MRSI.

PubMed

Kobus, Thiele; Wright, Alan J; Scheenen, Tom W J; Heerschap, Arend

2014-01-01

In many studies, it has been demonstrated that (1)H MRSI of the human prostate has great potential to aid prostate cancer management, e.g. in the detection and localisation of cancer foci in the prostate or in the assessment of its aggressiveness. It is particularly powerful in combination with T2 -weighted MRI. Nevertheless, the technique is currently mainly used in a research setting. This review provides an overview of the state-of-the-art of three-dimensional MRSI, including the specific hardware required, dedicated data acquisition sequences and information on the spectral content with background on the MR-visible metabolites. In clinical practice, it is important that relevant MRSI results become available rapidly, reliably and in an easy digestible way. However, this functionality is currently not fully available for prostate MRSI, which is a major obstacle for routine use by inexperienced clinicians. Routine use requires more automation in the processing of raw data than is currently available. Therefore, we pay specific attention in this review on the status and prospects of the automated handling of prostate MRSI data, including quality control. The clinical potential of three-dimensional MRSI of the prostate is illustrated with literature examples on prostate cancer detection, its localisation in the prostate, its role in the assessment of cancer aggressiveness and in the selection and monitoring of therapy.

16. 3-hydroxy-2(1H)-pyridinone chelating agents

DOEpatents

Raymond, K.N.; Xu, J.

1997-04-29

Disclosed is a series of improved metal chelating agents, which are highly effective upon both injection and oral administration; several of the most effective are of low toxicity. These chelating agents incorporate within their structure 1-hydroxy-2-pyridinone (1,2-HOPO) and 3-hydroxy-2-pyridinone (3,2-HOPO) moieties with a substituted carbamoyl group ortho to the hydroxy or oxo groups of the hydroxypyridinone ring. The electron-withdrawing carbamoyl group increases the acidity of the hydroxypyridinones. In the metal complexes of the chelating agents, the amide protons form very strong hydrogen bonds with its adjacent HOPO oxygen donor, making these complexes very stable at physiological conditions. The terminal N-substituents provides a certain degree of lipophilicity to the 3,2-HOPO, increasing oral activity. Also disclosed is a method of making the chelating agents and a method of producing a known compound, 3-hydroxy-1-alkyl-2(1H)pyridinone, used as a precursor to the chelating agent, safely and in large quantities. 2 figs.

17. 3-hydroxy-2(1H)-pyridinone chelating agents

DOEpatents

Raymond, Kenneth N.; Xu, Jide

1997-01-01

Disclosed is a series of improved metal chelating agents, which are highly effective upon both injection and oral administration; several of the most effective are of low toxicity. These chelating agents incorporate within their structure 1-hydroxy-2-pyridinone (1,2-HOPO) and 3-hydroxy-2-pyridinone (3,2-HOPO) moieties with a substituted carbamoyl group ortho to the hydroxy or oxo groups of the hydroxypyridinone ring. The electron-withdrawing carbamoyl group increases the acidity of the hydroxypyridinones. In the metal complexes of said chelating agents, the amide protons form very strong hydrogen bonds with its adjacent HOPO oxygen donor, making these complexes very stable at physiological conditions. The terminal N-substituents provides a certain degree of lipophilicity to said 3,2-HOPO, increasing oral activity. Also disclosed is a method of making the chelating agents and a method of producing a known compound, 3-hydroxy-1-alkyl-2(1H)pyridinone, used as a precursor to the chelating agent, safely and in large quantities.

18. 1H NMR Metabolomics Analysis of Glioblastoma Subtypes

PubMed Central

Cuperlovic-Culf, Miroslava; Ferguson, Dean; Culf, Adrian; Morin, Pier; Touaibia, Mohamed

2012-01-01

Glioblastoma multiforme (GBM) is the most common form of malignant glioma, characterized by unpredictable clinical behaviors that suggest distinct molecular subtypes. With the tumor metabolic phenotype being one of the hallmarks of cancer, we have set upon to investigate whether GBMs show differences in their metabolic profiles. 1H NMR analysis was performed on metabolite extracts from a selection of nine glioblastoma cell lines. Analysis was performed directly on spectral data and on relative concentrations of metabolites obtained from spectra using a multivariate regression method developed in this work. Both qualitative and quantitative sample clustering have shown that cell lines can be divided into four groups for which the most significantly different metabolites have been determined. Analysis shows that some of the major cancer metabolic markers (such as choline, lactate, and glutamine) have significantly dissimilar concentrations in different GBM groups. The obtained lists of metabolic markers for subgroups were correlated with gene expression data for the same cell lines. Metabolic analysis generally agrees with gene expression measurements, and in several cases, we have shown in detail how the metabolic results can be correlated with the analysis of gene expression. Combined gene expression and metabolomics analysis have shown differential expression of transporters of metabolic markers in these cells as well as some of the major metabolic pathways leading to accumulation of metabolites. Obtained lists of marker metabolites can be leveraged for subtype determination in glioblastomas. PMID:22528487

19. Preliminary 1H NMR study on archaeological waterlogged wood.

PubMed

Maccotta, Antonella; Fantazzini, Paola; Garavaglia, Carla; Donato, Ines D; Perzia, Patrizia; Brai, Maria; Morreale, Filippa

2005-01-01

Magnetic Resonance Relaxation (MRR) and Magnetic Resonance Imaging (MRI) are powerful tools to obtain detailed information on the pore space structure that one is unlikely to obtain in other ways. These techniques are particularly suitable for Cultural Heritage materials, because they use water 1H nuclei as a probe. Interaction with water is one of the main causes of deterioration of materials. Porous structure in wood, for example, favours the penetration of water, which can carry polluting substances and promote mould growth. A particular case is waterlogged wood from underwater discoveries and moist sites; in fact, these finds are very fragile because of chemical, physical and biological decay from the long contact with the water. When wood artefacts are brought to the surface and directly dried in air, there is the collapse of the cellular structures, and wood loses its original form and dimensions and cannot be used for study and museum exhibits. In this work we have undertaken the study of some wood finds coming from Ercolano's harbour by MRR and MRI under different conditions, and we have obtained a characterization of pore space in wood and images of the spatial distribution of the confined water in the wood.

20. The Structural Interface between HIV-1 Vif and Human APOBEC3H.

PubMed

Ooms, Marcel; Letko, Michael; Simon, Viviana

2017-03-01

Human APOBEC3H (A3H) is a cytidine deaminase that inhibits HIV-1 replication. To evade this restriction, the HIV-1 Vif protein binds A3H and mediates its proteasomal degradation. To date, little information on the Vif-A3H interface has been available. To decipher how both proteins interact, we first mapped the Vif-binding site on A3H by functionally testing a large set of A3H mutants in single-cycle infectivity and replication assays. Our data show that the two A3H α-helixes α3 and α4 represent the Vif-binding site of A3H. We next used viral adaptation and a set of Vif mutants to identify novel, reciprocal Vif variants that rescued viral infectivity in the presence of two Vif-resistant A3H mutants. These A3H-Vif interaction points were used to generate the first A3H-Vif structure model, which revealed that the A3H helixes α3 and α4 interact with the Vif β-sheet (β2-β5). This model is in good agreement with previously reported Vif and A3H amino acids important for interaction. Based on the predicted A3H-Vif interface, we tested additional points of contact, which validated our model. Moreover, these experiments showed that the A3H and A3G binding sites on HIV-1 Vif are largely distinct, with both host proteins interacting with Vif β-strand 2. Taken together, this virus-host interface model explains previously reported data and will help to identify novel drug targets to combat HIV-1 infection.IMPORTANCE HIV-1 needs to overcome several intracellular restriction factors in order to replicate efficiently. The human APOBEC3 locus encodes seven proteins, of which A3D, A3F, A3G, and A3H restrict HIV-1. HIV encodes the Vif protein, which binds to the APOBEC3 proteins and leads to their proteasomal degradation. No HIV-1 Vif-APOBEC3 costructure exists to date despite extensive research. We and others previously generated HIV-1 Vif costructure models with A3G and A3F by mapping specific contact points between both proteins. Here, we applied a similar approach to HIV

1. Metabolism of myo-[2-3H]Inositol and scyllo-[R-3H]Inositol in Ripening Wheat Kernels 1

PubMed Central

Sasaki, Ken; Loewus, Frank A.

1980-01-01

Injection of myo-[2-3H]inositol or scyllo-[R-3H]inositol into the peduncular cavity of wheat stalks about 2 to 4 weeks postanthesis led to rapid translocation into the spike and accumulation of label in developing kernels, especially the bran fraction. With myo-[2-3H]inositol, about 50 to 60% of the label was incorporated into high molecular weight cell wall substance in the region of the injection. That portion translocated to the kernels was utilized primarily for cell wall polysaccharide formation and phytate biosynthesis. A small amount was recovered as free myo-inositol and galactinol. When scyllo-[R-3H]inositol was supplied, most of the label was translocated into the developing kernels where it accumulated as free scyllo-inositol and O-α-d-galactopyranosyl-scyllo-inositol in approximately equal amount. None of the label from scyllo-[R-3H]inositol was utilized for either phytate biosynthesis or cell wall polysaccharide formation. PMID:16661513

2. An ignored but most favorable channel for NCO +C2H2 reaction

Xie, Hong-bin; Wang, Jian; Zhang, Shao-wen; Ding, Yi-hong; Sun, Chia-chung

2006-09-01

The NCO +C2H2 reaction has been considered as a prototype for understanding the chemical reactivity of the isocyanate radical towards unsaturated hydrocarbons in fuel-rich combustion. It has also been proposed to provide an effective route for formation of oxazole-containing compounds in organic synthesis, and might have potential applications in interstellar processes. Unfortunately, this reaction has met mechanistic controversy both between experiments and between experiments and theoretical calculations. In this paper, detailed theoretical investigations at the Becke's three parameter Lee-Yang-Parr-B3LYP /6-31G(d), B3LYP /6-311++G(d,p), quadratic configuration interaction with single and double excitations QCISD /6-31G(d), and Gaussian-3 levels are performed for the NCO +C2H2 reaction, covering various entrance, isomerization, and decomposition channels. Also, the highly cost-expensive coupled-cluster theory including single and double excitations and perturbative inclusion of triple excitations CCSD(T)/aug-cc-pVTZ single-point energy calculation is performed for the geometries obtained at the Becke's three parameter Lee-Yang-Parr-B3LYP /6-311++G(d,p) level. A previously ignored yet most favorable channel via a four-membered ring intermediate with allyl radical character is found. However, formation of P3 H +HCCNCO and the five-membered ring channel predicted by previous experimental and theoretical studies is kinetically much less competitive. With the new channel, master equation rate constant calculations over a wide range of temperatures (298-1500K) and pressures (10-560Torr) show that the predicted total rate constants exhibit a positive-temperature dependence and no distinct pressure dependence effect. This is in qualitative agreement with available experimental results. Under the experimental conditions, the predicted values are about 50% lower than the latest experimental results. Also, the branching ratio variations of the fragments P2 HCN +HCCO and P5

3. Nuclear magnetic resonance study of the ferroelastic phase transition of order-disorder type in [N(C2H5)4]2CdCl4

Lim, Ae Ran; Kim, Min Soo; Lim, Kye-Young

2016-08-01

This study uses nuclear magnetic resonance (NMR) techniques to examine the detailed changes in [N(C2H5)4]2CdCl4 around its phase transition at the temperature TC = 284 K. The chemical shifts and spin-lattice relaxation times in the rotating frame (T1ρ) were determined from 1H magic angle spinning (MAS) NMR and 13C cross-polarization (CP)/MAS NMR spectra. The two sets of inequivalent 1H and 13C nuclei in CH3 and CH2 were distinguished. A ferroelastic phase transition was observed at TC, without structural symmetry change. The phase transition is mainly attributed to the orientational ordering of the [N(C2H5)4]+ cations, and the spectral splitting at low temperature is associated with different ferroelastic domains.

4. Mapping Region of Human Restriction Factor APOBEC3H Critical for Interaction with HIV-1 Vif.

PubMed

Nakashima, Masaaki; Tsuzuki, Shinya; Awazu, Hiroaki; Hamano, Akiko; Okada, Ayaka; Ode, Hirotaka; Maejima, Masami; Hachiya, Atsuko; Yokomaku, Yoshiyuki; Watanabe, Nobuhisa; Akari, Hirofumi; Iwatani, Yasumasa

2017-03-21

The APOBEC3 (A3) family of cellular cytidine deaminases comprises seven members (A, B, C, D, F, G, and H) that potently inhibit retroviral replication. Human immunodeficiency virus type 1 (HIV-1) Vif is a small pleiotropic protein that specifically inactivates these enzymes, targeting them for ubiquitin-mediated proteasomal degradation. A3 Vif-interaction sites are presumed to fall into three distinct types: A3C/D/F, A3G, and A3H. To date, two types of A3G and A3C/D/F sites have been well characterized, whereas the A3H Vif-binding site remains poorly defined. Here, we explore the residues critical for the A3H-type Vif interaction. To avoid technical difficulties in performing experiments with human A3H haplotype II (hapII), which is relatively resistant to HIV-1 Vif, we employed its ortholog chimpanzee A3H (cA3H), which displays high Vif sensitivity, for a comparison of sensitivity with that of A3H hapII. The Vif susceptibility of A3H hapII-cA3H chimeras and their substitution mutants revealed a single residue at position 97 as a major determinant for the difference in their Vif sensitivities. We further surveyed critical residues by structure-guided mutagenesis using an A3H structural model and thus identified eight additional residues important for Vif sensitivity, which mapped to the α3 and α4 helices of A3H. Interestingly, this area is located on a surface adjacent to the A3G and A3C/D/F interfaces and is composed of negatively charged and hydrophobic patches. These findings suggest that HIV-1 Vif has evolved to utilize three dispersed surfaces for recognizing three types of interfaces on A3 proteins under certain structural constraints.

5. Significance of skeletal muscle digitalis receptors for [3H]ouabain distribution in the guinea pig.

PubMed

Kjeldsen, K; Nørgaard, A; Hansen, O; Clausen, T

1985-09-01

The importance of specific digitalis glycoside binding sites in skeletal muscle for the digitalis glycoside distribution in the guinea pig was evaluated using [3H]ouabain and [3H]digoxin binding assays. Measurements of [3H]ouabain binding capacity (EOmax) in gastrocnemius and heart muscles in vitro gave values of 474 +/- 15 and 1,092 +/- 39 pmol/g wet wt., respectively, in 4-week-old guinea pigs. Hence the total amount of [3H]ouabain binding sites in skeletal muscle and the heart was around 42,700 and 1,200 pmol, respectively. The apparent dissociation constants (Kd) for ouabain receptor interaction was 0.7 X 10(-7) and 1.5 X 10(-7) M for skeletal muscle and heart, respectively. Comparison of [3H]ouabain and [3H]digoxin binding revealed that these drugs are competitive. From birth to maturity the concentration of [3H]ouabain binding sites in guinea pigs decreased from 803 +/- 58 to 304 +/- 28 pmol/g wet wt. in gastrocnemius muscle and from 1,458 +/- 31 to 1,079 +/- 19 pmol/g wet wt. in the heart. After i.p. injection, measurements of the distribution of [3H]ouabain in plasma, skeletal muscle and the heart showed an almost equal relative specific occupancy of digitalis glycoside receptors in skeletal muscle and the heart: When 10% of the digitalis receptors in the heart were occupied by [3H]ouabain, 13% of those in the skeletal muscles were occupied. It was calculated that 1 hr after the i.p. administration of [3H]ouabain the amount of [3H]ouabain specifically bound to the skeletal muscles and the heart corresponded to 5 times and 1/10 the amount available in the extracellular pool, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

6. [Synthesis of selected derivatives of 3H-pyrido[2,3-d]pyrimidin-4-on and potential depressive action on OUN].

PubMed

Herold, F

1992-01-01

2-Methyl-4H-pyrido[2,3-d][1,3]oxazin-4-one (III) was reacted with amines IVa-j to give corresponding 2-methyl-3H-pyrido[2,3-d]pyrimidin-4-ones (Va-j) substituted at position 3. These reactions afforded non-cyclic by-products VIa', VIg', and VIh' which were converted into compounds Va, Vg and Vh by the action of POCl3. Structures of the newly obtained compounds have been confirmed by elemental analysis for C, H and N, and by IR and 1H NMR spectra.

7. Behavior of substances labeled with /sup 3/H-proline and /sup 3/H-fucose in the cellular processes of odontoblasts and ameloblasts

SciTech Connect

Warshawsky, H.; Josephsen, K.

1981-05-01

Odontoblasts are cells with single cytoplasmic processes that grow longer as more dentin is elaborated. Ameloblasts also have single processes and it has been postulated that they too grow longer as more enamel is made. Support for this hypothesis was obtained using rat incisors to investigate the behavior of substances labeled with /sup 3/H-proline and /sup 3/H-fucose. A comparison was made between odontoblasts, which have processes known to grow and remain within the dentin, and the ameloblasts whose Tomes' processes are hypothesized to grow and leave remnants in the completed enamel. With /sup 3/H-proline, the odontoblast bodies are labeled at the early time intervals. With /sup 3/H-fucose, the cell bodies are labeled at the early intervals and the newly formed glycoproteins are deposited into the predentin. Almost immediately, these are progressively added to the dentin at the calcification front. With time a gradient of labeling extends from the unlabeled dentin toward the odontoblast bodies. Unlike the behavior of labeled proteins, by 1 and 2 days labeled glycoproteins appear along the entire length of the odontoblast processes. In the enamel, no Tomes' processes are present during maturation. With /sup 3/H-proline, reactions are adjacent to the cells and diffuse toward, but do not reach the dentino-enamel junction by 1 and 2 days. With /sup 3/H-fucose, reactions appear over the enamel near the cells. By 1 and 2 days no diffusive pattern is seen, but grains are concentrated near the dentino-enamel junction, in a region containing holes known to be the beginning of Tomes' processes. Since odontoblast glycoproteins migrate along odontoblast processes, it was postulated that cytoplasmic remnants were present in enamel along which ameloblast glycoproteins could also migrate to reach the holes at the dentino-enamel junction.

8. Comparison of /sup 3/H-galactose and /sup 3/H-glucose as precursors of hepatic glycogen in control-fed rats

SciTech Connect

Michaels, J.E.; Garfield, S.A.; Hung, J.T.; Cardell, R.R. Jr.

1989-05-01

Labeling of hepatic glycogen derived from 3H-galactose and 3H-glucose was compared shortly after intravenous injection in control-fed rats. The rats were allowed to accumulate 5-8% glycogen prior to receiving label. Fifteen minutes to 2 hours after labeling, liver was excised and processed for routine light (LM) and electron microscopic (EM) radioautography (RAG) or biochemical analysis. After injection of 3H-galactose, LM-RAGs revealed that the percentage of heavily labeled hepatocytes increased from 37% after 15 minutes to 68% after 1 hour but showed no further increase after 2 hours. alpha-Amylase treatment removed most glycogen and incorporated label; thus few silver grains were observed, indicating little incorporation of label except into glycogen. EM-RAGs demonstrated that most label occurred where glycogen was located. Biochemical analysis showed initially a high blood level of label that rapidly plateaued at a reduced level by 5 minutes. Concomitantly, glycogen labeling determined by liquid scintillation counting reflected the increases observed in the RAGs. After injection of 3H-glucose, LM-RAGs revealed that only 12% of the hepatocytes were heavily labeled at 1 hour and 20% at 2 hours. In tissue treated with alpha-amylase, glycogen was depleted and label was close to background level at each interval observed. EM-RAGs showed most grains associated with glycogen deposits. Biochemically, blood levels of label persisted at a high level for 30 minutes and tissue levels increased slowly over the 2-hour period. This study shows that incorporation from 3H-galactose was more rapid than incorporation of 3H-glucose; however, label derived from both carbohydrates appeared to be incorporated mainly into glycogen.

9. Characterization of Samples from the 3H Evaporator System Including Effects of Recycle

SciTech Connect

Wilmarth, W.R.

2001-05-15

Analysis of several series of samples from the 3H Evaporator System have been completed. The goal of this work was to determine the effects of 3H operation including recycle of concentrated supernate from Tank 30H into the sludge layer of Tank 32H.

10. Binding of (/sup 3/H)forskolin to solubilized preparations of adenylate cyclase

SciTech Connect

Nelson, C.A.; Seamon, K.B.

1988-01-01

The binding of (/sup 3/H)forskolin to proteins solubilized from bovine brain membranes was studied by precipitating proteins with polyethylene glycol and separating (/sup 3/H)forskolin bound to protein from free (/sup 3/H)forskolin by rapid filtration. The K/sub d/ for (/sup 3/H)forskolin binding to solubilized proteins was 14 nM which was similar to that for (/sup 3/H)forskolin binding sites in membranes from rat brain and human platelets. Forskolin analogs competed for (/sup 3/H)forskolin binding sites with the same rank potency in both brain membranes and in proteins solubilized from brain membranes. (/sup 3/H)forskolin bound to proteins solubilized from membranes with a Bmax of 38 fmolmg protein which increased to 94 fmolmg protein when GppNHp was included in the binding assay. In contrast, GppNHp had no effect on (/sup 3/H)forskolin binding to proteins solubilized from membranes preactivated with GppNHp. Solubilized adenylate cyclase from non-preactivated membranes had a basal activity of 130 pmolmgmin which was increased 7-fold by GppNHp. In contrast, adenylate cyclase from preactivated membranes had a basal activity of 850 pmolmgmin which was not stimulated by GppNHp or forskolin

11. Morphine enhances the release of /sup 3/H-purines from rat brain cerebral cortical prisms

SciTech Connect

Wu, P.H.; Phillis, J.W.; Yuen, H.

1982-10-01

In vitro experiments have shown that /sup 3/H-purines can be released from /sup 3/H-adenosine preloaded rat brain cortical prisms by a KCl-evoked depolarization. The KCl-evoked release of /sup 3/H-purines is dependent on the concentration of KCl present in the superfusate. At concentrations of 10(-7) approximately 10(-5)M morphine did not influence the basal release of /sup 3/H-purines from the prisms, although it enhanced the KCl-evoked release of /sup 3/H-purines. The enhancement of KCl-evoked /sup 3/H-purine release by morphine was concentration-dependent and was antagonized by naloxone, suggesting the involvement of opiate receptors. Uptake studies with rat brain cerebral cortical synaptosomes show that morphine is a very weak inhibitor of adenosine uptake. Comparisons with dipyridamole, a potent inhibitor of adenosine uptake, suggest that this low level of inhibition of the uptake did not contribute significantly to the release of /sup 3/H-purine by morphine seen in our experiments. It is therefore suggested that morphine enhances KCl-evoked /sup 3/H-purine release by an interaction with opiate receptors and that the resultant increase in extracellular purine (adenosine) levels may account for some of the actions of morphine.

12. Nuclear accident-derived (3)H in river water of Fukushima Prefecture during 2011-2014.

PubMed

Ueda, Shinji; Hasegawa, Hidenao; Kakiuchi, Hideki; Ochiai, Shinya; Akata, Naofumi; Hisamatsu, Shun'ichi

2015-08-01

During 2011-2014, we measured (3)H concentrations in river water samples collected during base flow conditions and during several flood events from two small rivers in a mountainous area in Fukushima Prefecture, which received deposition of (137)Cs from the Fukushima Dai-ichi Nuclear Power Plant accident. (3)H concentrations above background levels were found in water samples collected during both base flow conditions and flood events in 2011. The (3)H concentrations during flood events were generally higher than those during base flow conditions. The (3)H concentrations in both rivers during base flow conditions and flood events decreased with time after the accident and reached almost background levels in 2013. We also measured (3)H concentrations in freshwater samples from 16 other rivers and one dam in eastern Fukushima Prefecture from 2012 to 2014 during base flow conditions. The measured (3)H concentrations were higher than the background level in 2012 and decreased with time. The (137)Cs inventory in the catchment area at each sampling point was estimated from air-borne monitoring results in the literature and compared with the (3)H concentrations. We found surprisingly good correlations between (137)Cs inventories in the catchment areas and (3)H concentrations in the water samples. Further studies will be necessary to clarify the reason for the good correlation.

13. Elevated ZC3H15 increases HCC growth and predicts poor survival after surgical resection

PubMed Central

Li, Li-mei; Liu, Hui; Fu, Si-yuan; Yang, Yuan; Zhang, Jin; Yuan, Shen-xian; Wang, Ruo-yu; Yang, Yun; Gu, Fang-ming; Dong, Li-wei; Pan, Ze-ya; Zhou, Wei-ping

2016-01-01

Zinc finger CCCH-type containing 15 (ZC3H15), also known as DRG family regulatory protein 1 (DFRP1), is a highly conserved eukaryotic protein that associates with active translation machinery. The aim of our study was to explore the clinical relevance and intrinsic functions of ZC3H15 in hepatocellular carcinoma (HCC). We constructed a cohort with 261 tumor and matched normal tissues from HCC patients. ZC3H15 protein and mRNA levels were determined using immunohistochemistry, western blot analysis, and quantitative polymerase chain reaction. ZC3H15 was highly expressed in the majority of HCC cases, and high ZC3H15 levels were significantly associated with high serum a-fetoprotein (AFP) levels (>20 ng/mL) and vascular invasion. Kaplan-Meier and Cox regression data indicated that elevated ZC3H15 was an independent predictor for HCC-specific disease-free survival (hazards ratio [HR], 1.789; 95% confidence interval [95% CI], 1.298-2.466 [P=0.0004]) and overall survival (HR, 1.613; 95% CI, 1.120-2.322 [P=0.0101]). Interaction of ZC3H15 with TRAF2 increased activation of NFκB signaling. These results suggest ZC3H15 is an independent prognostic marker in HCC patients that is clinicopathologically associated with tumor invasion and serum AFP levels. PMID:27191988

14. Volumetric Properties of the Mixture Propenenitrile C3H3N + C3H6O2 Methyl ethanoate (VMSD1511, LB4267_V)

Cibulka, I.; Fontaine, J.-C.; Sosnkowska-Kehiaian, K.; Kehiaian, H. V.

This document is part of Subvolume C 'Binary Liquid Systems of Nonelectrolytes III' of Volume 26 'Heats of Mixing, Vapor-Liquid Equilibrium, and Volumetric Properties of Mixtures and Solutions' of Landolt-Börnstein Group IV 'Physical Chemistry'. It contains the Chapter 'Volumetric Properties of the Mixture Propenenitrile C3H3N + C3H6O2 Methyl ethanoate (VMSD1511, LB4267_V)' providing data from direct measurement of low-pressure thermodynamic speed of sound at variable mole fraction and constant temperature, in the single-phase region(s).

15. Volumetric Properties of the Mixture Propenenitrile C3H3N + C3H6O2 Methyl ethanoate (VMSD1412, LB4273_V)

Cibulka, I.; Fontaine, J.-C.; Sosnkowska-Kehiaian, K.; Kehiaian, H. V.

This document is part of Subvolume C 'Binary Liquid Systems of Nonelectrolytes III' of Volume 26 'Heats of Mixing, Vapor-Liquid Equilibrium, and Volumetric Properties of Mixtures and Solutions' of Landolt-Börnstein Group IV 'Physical Chemistry'. It contains the Chapter 'Volumetric Properties of the Mixture Propenenitrile C3H3N + C3H6O2 Methyl ethanoate (VMSD1412, LB4273_V)' providing data by calculation of isentropic compressibility from low-pressure density and thermodynamic speed of sound data at variable mole fraction and constant temperature, in the single-phase region(s).

16. Volumetric Properties of the Mixture Propenenitrile C3H3N + C3H8O Propan-1-ol (VMSD1511, LB4926_V)

Cibulka, I.; Fontaine, J.-C.; Sosnkowska-Kehiaian, K.; Kehiaian, H. V.

This document is part of Subvolume C 'Binary Liquid Systems of Nonelectrolytes III' of Volume 26 'Heats of Mixing, Vapor-Liquid Equilibrium, and Volumetric Properties of Mixtures and Solutions' of Landolt-Börnstein Group IV 'Physical Chemistry'. It contains the Chapter 'Volumetric Properties of the Mixture Propenenitrile C3H3N + C3H8O Propan-1-ol (VMSD1511, LB4926_V)' providing data from direct measurement of low-pressure thermodynamic speed of sound at variable mole fraction and constant temperature, in the single-phase region(s).

17. A combined crossed beam and theoretical investigation of O(3P)+C3H3→C3H2+OH

Lee, Hohjai; Joo, Sun-Kyu; Kwon, Lee-Kyoung; Choi, Jong-Ho

2004-02-01

18. Kinetics of the hydrogen abstraction C2H3* + alkane --> C2H4 + alkyl radical reaction class.

PubMed

Muszyńska, Marta; Ratkiewicz, Artur; Huynh, Lam K; Truong, Thanh N

2009-07-23

This paper presents an application of the reaction class transition state theory (RC-TST) to predict thermal rate constants for hydrogen abstraction reactions of the type C(2)H(3) + alkane --> C(2)H(4) + alkyl radical. The linear energy relationship (LER) was proven to hold for both noncyclic and cyclic hydrocarbons. We have derived all parameters for the RC-TST method from rate constants of 19 representative reactions, coupling with LER and the barrier height grouping (BHG) approach. Both the RC-TST/LER, where only reaction energy is needed, and the RC-TST/BHG, where no other information is needed, can predict rate constants for any reaction in this reaction class with satisfactory accuracy for combustion modeling. Our analysis indicates that less than 90% systematic errors on the average exist in the predicted rate constants using the RC-TST/LER or RC-TST/BHG method, while in comparison to explicit rate calculations, the differences are within a factor of 2 on the average.

19. Physical and spectroscopic properties of pure C2H4 and CH4:C2H4 ices

Molpeceres, Germán; Satorre, Miguel Angel; Ortigoso, Juan; Zanchet, Alexandre; Luna, Ramón; Millán, Carlos; Escribano, Rafael; Tanarro, Isabel; Herrero, Víctor J.; Maté, Belén

2017-04-01

Physical and spectroscopic properties of ices of C2H4 and CH4:C2H4 mixtures with 3:1, 1:1 and 1:3 ratios have been investigated at 30 K. Two laboratories are involved in this work. In one of them, the density and refractive index of the samples have been measured by using a cryogenic quartz microbalance and laser interferometric techniques. In the other one, IR spectra have been recorded in the near- and mid-infrared regions, and band shifts with respect to the pure species, band strengths of the main bands, and the optical constants in both regions have been determined. Previous data on ethylene and the mixtures studied here were scarce. For methane, both the wavenumbers and band strengths have been found to follow a regular pattern of decrease with increasing dilution, but no pattern has been detected for ethylene vibrations. The method employed for the preparation of the samples, by vapour deposition under vacuum, is thought to be adequate to mimic the structure of astrophysical ices. Possible astrophysical implications, especially by means of the optical constants reported here, have been discussed.

20. catena-Poly[[[aqua-bis-(1H-imidazole-κN(3))copper(II)]-μ-furan-2,5-di-car-boxylato-κ(2)O(2):O(5)] trihydrate].

PubMed

Li, Ya-Feng; Xu, Yue; Qin, Xiao-Lin; Gao, Wen-Yuan; Gao, Yue

2012-05-01

In the title cooridnation polymer, {[Cu(C(6)H(2)O(5))(C(3)H(4)N(2))(2)(H(2)O)]·3H(2)O}(n), an infinite chain is formed along [001] by linking of the Cu(C(3)N(2)H(4))(2)(H(2)O) entities with two bridging monodentate carboxyl-ate groups of two different furan-2,5-dicarboxyl-ate dianions. The geometry of the Cu(2+) ion is a square-based pyramid with the water atom in the apical position and the ligand O and N atoms in a trans orientation. The dihedral angle between the imidazole planes is 83.96 (14)°. O(w)-H⋯O and N(i)-H⋯O (w = water and i = imidazole) hydrogen bonds help to establish the packing.

1. Chanabayaite, Cu2(N3C2H2)Cl(NH3,Cl,H2O,□)4, a new mineral containing triazolate anion

Chukanov, N. V.; Zubkova, N. V.; Möhn, G.; Pekov, I. V.; Pushcharovsky, D. Yu.; Zadov, A. E.

2015-12-01

A new mineral, chanabayaite, has been discovered at a guano deposit located at Mt. Pabellón de Pica near the village of Chanabaya, Iquique Province, Tarapacá region, Chile. It is associated with salammoniac, halite, joanneumite, nitratine and earlier chalcopyrite. Chanabayaite occurs as blue translucent imperfect prismatic crystals, up to 0.05 × 0.1 × 0.5 mm in size, and their radial aggregates. Chanabayaite is brittle, with a Mohs' hardness of 2. The cleavage is perfect on (001) and imperfect on (100) and (010). D meas = 1.48(2) g/cm3, D calc = 1.464 g/cm3. The mineral is optically biaxial (-), α = 1.561(2), β = 1.615(3), γ = 1.620(2), 2 V meas = 25(10)°, 2 V calc = 33°. Pleochroism is strong, Z ≈ Y (deep blue) ≫ X (pale blue with gray tint). IR spectrum is given. The chemical composition (electron microprobe data for Cu, Fe and Cl; gas chromatography data for H, N, C and O) is as follows (wt %): 32.23 Cu, 1.14 Fe, 16.13 Cl, 3.1 H, 29.9 N, 12.2 C, 3.4 O, total is 98.1. The empirical formula is ( Z = 4): Cu1.92Fe0.08Cl1.72N8.09C3.85H11.66O0.81. The structural model was based on the single-crystal X-ray diffraction data ( R = 0.1627). Chanabayaite is orthorhombic, space group Imma, a = 19.484(3), b = 7.2136(10), c = 11.999(4) Å, V = 1686.5(7) Å3, Z = 2. In chanabayaite, chains of the corner-sharing Cu(l)-centered octahedra and single Cu(2)-centered octahedra are linked via 1,2,4-triazolate anions C2N3H2 -. NH3 and Cl- are additional ligands coordinating Cu2+. Chanabayaite is a transformational mineral species formed by leaching of Na and one third of Cl and partial dehydration of the protophase Na2Cu2Cl3(N3C2H2)2(NH3)2 • 4H2O. The strongest reflections in the powder X-ray diffraction pattern [ d, Å ( I, %) ( hkl)] are detected: 10.19 (100) (101), 6.189 (40) (011), 5.729 (23) (301), 5.216 (75) (211, 202), 4.964 (20) (400), 2.830 (20) (602, 413, 503), 2.611 (24) (123, 422, 404).

2. Concentration of (3)H in plants around Fukushima Dai-ichi Nuclear Power Station.

PubMed

Kakiuchi, Hideki; Akata, Naofumi; Hasegawa, Hidenao; Ueda, Shinji; Tokonami, Shinji; Yamada, Masatoshi; Hosoda, Masahiro; Sorimachi, Atsuyuki; Tazoe, Hirofumi; Noda, Kaori; Hisamatsu, Shun'ichi

2012-01-01

A large amount of radionuclides was released from the Fukushima Dai-ichi Nuclear Power Station (FDNPS) following the damage caused by the tsunami due to the Great East Japan Earthquake on 11 March 2011. Although many radionuclides in various environmental samples around the FDNPS have been measured, (3)H in the terrestrial environment has not yet been reported. We present here the first survey results of (3)H concentrations in plant samples collected around the FDNPS in 2011 from shortly after the accident. The free-water (3)H concentrations in herbaceous plant shoots and evergreen tree leaves were considerably higher than the previous background concentration, and diminished with distance from the FDNPS. Although reconstruction of atmospheric (3)H concentrations after the accident is difficult, a rough estimate of the radiation dose due to (3)H inhalation about 20 km from the FDNPS is on the order of a few microsieverts (μSv).

3. 2H NMR studies of supercooled and glassy aspirin

Nath, R.; Nowaczyk, A.; Geil, B.; Bohmer, R.

2007-11-01

Acetyl salicylic acid, deuterated at the methyl group, was investigated using 2H-NMR in its supercooled and glassy states. Just above the glass transition temperature the molecular reorientations were studied using stimulated-echo spectroscopy and demonstrated a large degree of similarity with other glass formers. Deep in the glassy phase the NMR spectra look similar to those reported for the crystal [A. Detken, P. Focke, H. Zimmermann, U. Haeberlen, Z. Olejniczak, Z. T. Lalowicz, Z. Naturforsch. A 50 (1995) 95] and below 20 K they are indicative for rotational tunneling with a relatively large tunneling frequency. Measurements of the spin-lattice relaxation times for temperatures below 150 K reveal a broad distribution of correlation times in the glass. The dominant energy barrier characterizing the slow-down of the methyl group is significantly smaller than the well defined barrier in the crystal.

4. Vibrational and Rotational Spectroscopy of CD_2H^+

Asvany, Oskar; Jusko, Pavol; Brünken, Sandra; Schlemmer, Stephan

2016-06-01

The lowest rotational levels (J=0-5) of the CD_2H^+ ground state have been probed by high-resolution rovibrational and pure rotational spectroscopy in a cryogenic 22-pole ion trap. For this, the ν_1 rovibrational band has been revisited, detecting 107 transitions, among which 35 are new. The use of a frequency comb system allowed to measure the rovibrational transitions with high precision and accuracy, typically better than 1 MHz. The high precision has been confirmed by comparing combination differences in the ground and vibrationally excited state. For the ground state, this allowed for equally precise predictions of pure rotational transitions, 24 of which have been measured directly by a novel IR - mm-wave double resonance method. M.-F. Jagod et al, J. Molec. Spectrosc. 153, 666, 1992 S. Gartner et al, J. Phys. Chem. A 117, 9975, 2013

5. Tris(5-amino-1H-1,2,4-triazol-4-ium) dihydrogenphosphate hydrogen­phosphate trihydrate

PubMed Central

Mrad, Mohamed Lahbib; Zeller, Matthias; Hernandez, Kristen J.; Rzaigui, Mohamed; Ben Nasr, Cherif

2012-01-01

In the crystal structure of the title molecular salt, 3C2H5N4 +·HPO4 2−·H2PO4 −·3H2O, the phosphate-based framework is built upon layers parallel to (010) made up from the H2PO4 − and HPO4 2− anions and water mol­ecules, which are inter­connected through O—H⋯O hydrogen bonds. The organic cations are located between the phosphate–water layers and are connected to them via N—H⋯O hydrogen bonds. The bond-length features are consistent with an imino resonance form for the exocyclic amino group, as is commonly found for a C—N single bond involving sp 2-hybridized C and N atoms. PMID:23468776

6. 2H and 18O Freshwater Isoscapes of Scotland

Meier-Augenstein, Wolfram; Hoogewerff, Jurian; Kemp, Helen; Frew, Danny

2013-04-01

Scotland's freshwater lochs and reservoirs provide a vital resource for sustaining biodiversity, agriculture, food production as well as for human consumption. Regular monitoring of freshwaters by the Scottish Environment Protection Agency (SEPA) fulfils legislative requirements with regards to water quality but new scientific methods involving stable isotope analysis present an opportunity combining these mandatory monitoring schemes with fundamental research to inform and deliver on current and nascent government policies [1] through gaining a greater understanding of Scottish waters and their importance in the context of climate change, environmental sustainability and food security. For example, 2H and 18O isoscapes of Scottish freshwater could be used to underpin research and its applications in: • Climate change - Using longitudinal changes in the characteristic isotope composition of freshwater lochs and reservoirs as proxy, isoscapes will provide a means to assess if and how changes in temperature and weather patterns might impact on precipitation patterns and amount. • Scottish branding - Location specific stable isotope signatures of Scottish freshwater have the potential to be used as a tool for provenancing and thus protecting premium Scottish produce such as Scottish beef, Scottish soft fruit and Scottish Whisky. During 2011 and 2012, with the support of SEPA more than 110 samples from freshwater lochs and reservoirs were collected from 127 different locations across Scotland including the Highlands and Islands. Here we present the results of this sampling and analysis exercise isotope analyses in form of 2H and 18O isoscapes with an unprecedented grid resolution of 26.5 × 26.5 km (or 16.4 × 16.4 miles). [1] Adaptation Framework - Adapting Our Ways: Managing Scotland's Climate Risk (2009): Scotland's Biodiversity: It's in Your Hands - A strategy for the conservation and enhancement of biodiversity in Scotland (2005); Recipe For Success - Scotland

7. Photoaffinity labeling of the dopamine reuptake carrier protein with 3-azido sup 3 H GBR-12935

SciTech Connect

Berger, S.P.; Martenson, R.E.; Laing, P.; Thurkauf, A.; Decosta, B.; Rice, K.C.; Paul, S.M. )

1991-04-01

A high affinity tritiated azido-diphenylpiperazine derivative, 3-azido {sup 3}H GBR-12935, was synthesized as a potential photoaffinity probe of the dopamine transporter. Initially, the reversible binding of 3-azido {sup 3}H GBR-12935 to crude synaptosomal membranes from the rat striatum was characterized. Specific binding was sodium dependent and inhibited by a variety of drugs that are known to potently inhibit dopamine uptake. Other neurotransmitter uptake inhibitors, as well as cis-flupenthixol, a potent inhibitor of {sup 3}
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