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Radioanalytical studies of fallout 63Ni.
Holm, E; Roos, P; Skwarzec, B
Fallout of Nickel-63 (T1/2 = 100 a) produced in small amounts at nuclear weapon tests following the neutron activation of weapon construction material was investigated by studying carpets of lichen collected during 1961 to 1988 at the Lake Rogen district in central Sweden (62.3 degrees N, 12.4 degrees E). The maximal level of 63Ni in the lichen carpet, which occurred in 1964, was about 0.6 Bq kg-1, dry weight, and decreased to 0.1 Bq kg-1 in 1988. The deposition pattern for 63Ni was similar to other fallout radionuclides such as 137Cs, 90Sr and 239 + 240Pu. The concentrations of stable Ni were relatively constant at 0.5 to 1.0 microgram g-1 throughout the years resulting in, for example, a specific activity (63Ni/stable Ni) of 0.5 Bq mg-1 in 1964 and 0.1 Bq mg-1 in 1988. The total area content of 63Ni was estimated to be 1.0 Bq m-2 and the activity ratio 63Ni/60Co was estimated to be 0.03 in 1966. The Chernobyl accident in April 1986 did not significantly increase the levels of 63Ni. For the measurement of these extremely low-levels of 63Ni, 200 g of dry material (about 1 kg fresh) were ashed and leached with aqua regia after hydroxides had been precipitated with ammonia, leaving Ni in the aqueous phase. Nickel was extracted as a dimethylglyoxime complex by chloroform and back-extracted with HCl. Finally, Ni was electroplated onto copper discs from an ammonium sulfate medium at high pH. The radiochemical yield was determined by atomic absorption spectrometry of stable Ni before and after electrodeposition.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:1310303
Application of TDCR-Geant4 modeling to standardization of 63Ni.
Thiam, C; Bobin, C; Chauvenet, B; Bouchard, J
As an alternative to the classical TDCR model applied to liquid scintillation (LS) counting, a stochastic approach based on the Geant4 toolkit is presented for the simulation of light emission inside the dedicated three-photomultiplier detection system. To this end, the Geant4 modeling includes a comprehensive description of optical properties associated with each material constituting the optical chamber. The objective is to simulate the propagation of optical photons from their creation in the LS cocktail to the production of photoelectrons in the photomultipliers. First validated for the case of radionuclide standardization based on Cerenkov emission, the scintillation process has been added to a TDCR-Geant4 modeling using the Birks expression in order to account for the light-emission nonlinearity owing to ionization quenching. The scintillation yield of the commercial Ultima Gold LS cocktail has been determined from double-coincidence detection efficiencies obtained for (60)Co and (54)Mn with the 4π(LS)β-γ coincidence method. In this paper, the stochastic TDCR modeling is applied for the case of the standardization of (63)Ni (pure β(-)-emitter; E(max)=66.98 keV) and the activity concentration is compared with the result given by the classical model. PMID:22436447
63Ni (n ,γ ) cross sections measured with DANCE
NASA Astrophysics Data System (ADS)
Weigand, M.; Bredeweg, T. A.; Couture, A.; Göbel, K.; Heftrich, T.; Jandel, M.; Käppeler, F.; Lederer, C.; Kivel, N.; Korschinek, G.; Krtička, M.; O'Donnell, J. M.; Ostermöller, J.; Plag, R.; Reifarth, R.; Schumann, D.; Ullmann, J. L.; Wallner, A.
The neutron capture cross section of the s -process branch nucleus
Intrinsically radiolabelled [59Fe]-SPIONs for dual MRI/radionuclide detection
Hoffman, David; Sun, Minghao; Yang, Likun; McDonagh, Philip R; Corwin, Frank; Sundaresan, Gobalakrishnan; Wang, Li; Vijayaragavan, Vimalan; Thadigiri, Celina; Lamichhane, Narottam; Zweit, Jamal
Towards the development of iron oxide nanoparticles with intrinsically incorporated radionuclides for dual Positron Emission Tomography/Magnetic Resonance Imaging (PET/MRI) and more recently of Single Photon Emission Computed Tomography/Magnetic Resonance Imaging (SPECT/MRI), we have developed intrinsically radiolabeled [59Fe]-superparamagnetic iron oxide nanoparticles ([59Fe]-SPIONs) as a proof of concept for an intrinsic dual probe strategy. 59Fe was incorporated into Fe3O4 nanoparticle crystal lattice with 92±3% efficiency in thermal decomposition synthesis. Multidentate poly(acrylic acid)-dopamine-poly(ethylene-glycol-2000) (PAA-DOP-PEG) ligands were designed and synthesized based on facile EDC chemistry and utilized to functionalize the [59Fe]-SPIONs. The transverse relaxivity of [59Fe]-SPIONs (97±3 s-1mM-1) was characterized and found to be similar to non-radioactive SPIONs (72±10 s-1mM-1), indicating that 59Fe incorporation does not alter the SPIONs' MRI contrast properties. [59Fe]-SPIONs were used to evaluate the nanoparticle biodistribution by ex vivo gamma counting and MRI. Nude mice (n=15) were injected with [59Fe]-SPIONs and imaged at various time points with 7T small animal MRI scanner. Ex vivo biodistribution was evaluated by tissue-based gamma counting. MRI signal contrast qualitatively correlates with the %ID/g of [59Fe]-SPIONs, with high contrast in liver (45±6%), medium contrast in kidneys (21±5%), and low contrast in brain (4±6%) at 24 hours. This work demonstrates the synthesis and in vivo application of intrinsically radiolabeled [59Fe]-SPIONs for bimodal detection and provides a proof of concept for incorporation of both gamma- and positron-emitting inorganic radionuclides into the core of metal based MRI contrast agent nanoparticles. PMID:25250204
{beta}{sup +} Decay Partial Half-Life of {sup 54}Mn and Cosmic Ray Chronometry
Wuosmaa, A.H.; Ahmad, I.; Fischer, S.M.; Greene, J.P.; Hackman, G.; Nanal, V.; Savard, G.; Schiffer, J.P.; Wilt, P.; Austin, S.M.; Brown, B.A.; Freedman, S.J.; Connell, J.J.
The weak {beta}{sup +} decay of the astrophysically significant radioisotope {sup 54}Mn has been observed. The energies of positrons from a chemically purified {sup 54}Mn source were measured using the APEX spectrometer at Argonne National Laboratory. We deduce a {beta}{sup +} decay branch of (1.20{plus_minus}0.26){times}10{sup {minus}9} , corresponding to a partial half-life of (7.1{plus_minus}1.5){times}10{sup 8} yr . The implications of this value for cosmic-ray confinement times are discussed in light of recent satellite measurements of the cosmic-ray abundance of {sup 54}Mn . {copyright} {ital 1998} {ital The American Physical Society}
{beta}{sup +} decay and cosmic-ray half-life of {sup 54}Mn
da Cruz, M.T.F.; Norman, E.B.; Chan, Y.D.; Garcia, A.; Larimer, R.M.; Lesko, K.T.; Stokstad, R.G.; Wietfeldt, F.E. |; Hindi, M.M.; Zlimen, I.
We performed a search for the {beta}{sup +} branch of {sup 54}Mn decay. As a cosmic ray, {sup 54}Mn, deprived of its atomic electrons, can decay only via {beta}{sup +} and {beta}{sup {minus}} decay, with a half-life of the order of 10{sup 6} yr. This turns {sup 54} Mn into a suitable cosmic chronometer for the study of cosmic-ray confinement times. We searched for coincident back-to-back 511-keV {gamma}-rays using two germanium detectors inside a Nal(Tl) annulus. An upper limit of 2{times}10{sup {minus}8} was found for the {beta}{sup +} decay branch, corresponding to a lower limit of 13.7 for the log ft value.
/sup 54/Mn absorption and excretion in rats fed soy protein and casein diets
Lee, D.Y.; Johnson, P.E.
Rats were fed diets containing either soy protein or casein and different levels of manganese, methionine, phytic acid, or arginine for 7 days and then fed test meals labeled with 2 microCi of 54Mn after an overnight fast. Retention of 54Mn in each rat was measured every other day for 21 days using a whole-body counter. Liver manganese was higher (P less than 0.0001) in soy protein-fed rats (8.8 micrograms/g) than in casein-fed rats (5.2 micrograms/g); manganese superoxide dismutase activity also was higher in soy protein-fed rats than in casein-fed rats (P less than 0.01). There was a significant interaction between manganese and protein which affected manganese absorption and biologic half-life of 54Mn. In a second experiment, rats fed soy protein-test meals retained more 54Mn (P less than 0.001) than casein-fed rats. Liver manganese (8.3 micrograms/g) in the soy protein group was also higher than that (5.7 micrograms/g) in the casein group (P less than 0.0001), but manganese superoxide dismutase activity was unaffected by protein. Supplementation with methionine increased 54Mn retention from both soy and casein diets (P less than 0.06); activity of manganese superoxide dismutase increased (P less than 0.05) but liver manganese did not change. The addition of arginine to casein diets had little effect on manganese bioavailability. Phytic acid affected neither manganese absorption nor biologic half-life in two experiments, but it depressed liver manganese in one experiment. These results suggest that neither arginine nor phytic acid was the component in soy protein which made manganese more available from soy protein diets than casein diets.
Measurement of 59Ni and 63Ni by accelerator mass spectrometry at CIAE
NASA Astrophysics Data System (ADS)
Wang, Xiaoming; He, Ming; Ruan, Xiangdong; Xu, Yongning; Shen, Hongtao; Du, Liang; Xiao, Caijin; Dong, Kejun; Jiang, Shan; Yang, Xuran; Lan, Xiaoxi; Wu, Shaoyong; Zhao, Qingzhang; Cai, Li; Pang, Fangfang
The long lived isotopes 59Ni and 63Ni can be used in many areas such as radioactive waste management, neutron dosimetry, cosmic radiation study, and so on. Based on the large accelerator and a big Q3D magnetic spectrometer, the measurement method for 59Ni and 63Ni is under development at the AMS facility at China Institute of Atomic Energy (CIAE). By using the ΔE-Q3D technique with the Q3D magnetic spectrometer, the isobaric interferences were greatly reduced in the measurements of 59Ni and 63Ni. A four anode gas ionization chamber was then used to further identify isobars. With these techniques, the abundance sensitivities of 59Ni and 63Ni measurements are determined as 59Ni/Ni = 1 × 10-13 and 63Ni/Ni = 2 × 10-12, respectively.
Evidence for correlations between fluctuations in 54Mn decay rates and solar storms
NASA Astrophysics Data System (ADS)
Mohsinally, T.; Fancher, S.; Czerny, M.; Fischbach, E.; Gruenwald, J. T.; Heim, J.; Jenkins, J. H.; Nistor, J.; O'Keefe, D.
Following recent indications that several radioactive isotopes show fluctuating decay rates which may be influenced by solar activity, we present findings from a 2 year period of data collection on 54Mn. Measurements were recorded hourly from a 1 μCi sample of 54Mn monitored from January 2010-December 2011. A series of signal-detection algorithms determine regions of statistically significant fluctuations in decay behaviour from the expected exponential form. The 239 decay flags identified during this interval were compared to daily distributions of multiple solar indices, generated by NOAA, which are associated with heightened solar activity. The indices were filtered to provide a list of the 413 strongest events during a coincident period. We find that 49% of the strongest solar events are preceded by at least 1 decay flag within a 48 h interval, and 37% of decay flags are followed by a reported solar event within 48 h. These results are significant at the 0.9σ and 2.8σ levels respectively, based on a comparison to results obtained from a shuffle test, in which the decay measurements were randomly shuffled in time 10,000 times. We also present results from a simulation combining constructed data reflecting 10 sites which compared and filtered decay flags generated from all sites. The results indicate a potential 35% reduction in the false positive rate in going from 1 to 10 sites. By implication, the improved statistics attest to the benefit of analysing data from a larger number of geographically distributed sites in parallel.
Standardization of (59)Fe by 4π(PC)β-γ software coincidence system.
Koskinas, M F; Polillo, G; Brancaccio, F; Yamazaki, I M; Dias, M S
The procedure for the standardization of (59)Fe using a 4π(PC)β-γ software coincidence system is described. The standardization was performed with an experimental setup consisting of a thin window gas-flow proportional counter (PC) in 4π geometry coupled to a NaI(Tl) scintillator and to a HPGe detector. The data acquisition was carried out by means of a Software Coincidence System (SCS). The beta efficiency was changed by using Collodion films and aluminum foils as external absorbers. PMID:26688361
Bioaccumulation of (63)Ni in the scleractinian coral Stylophora pistillata and isolated Symbiodinium using radiotracer techniques.
Hédouin, Laetitia; Metian, Marc; Teyssié, Jean-Louis; Oberhänsli, François; Ferrier-Pagès, Christine; Warnau, Michel
Development of nickel mining activities along the New Caledonia coasts threatens the biodiversity of coral reefs. Although the validation of tropical marine organisms as bioindicators of metal mining contamination has received much attention in the literature over the last decade, few studies have examined the potential of corals, the fundamental organisms of coral reefs, to monitor nickel (Ni) contamination in tropical marine ecosystems. In an effort to bridge this gap, the present work investigated the bioaccumulation of (63)Ni in the scleractinian coral Stylophora pistillata and in its isolated zooxanthellae Symbiodinium, using radiotracer techniques. Results highlight the high capacities of coral tissues (zooxanthellae and host tissues) to efficiently bioconcentrate (63)Ni compared to skeleton (Concentration Factors CF at 14 days of exposure are 3 orders of magnitude higher in tissues than in skeleton). When non-contaminated conditions were restored, (63)Ni was more efficiently retained in skeleton than in coral tissues, with biological half-lives (Tb½) of 44.3 and 6.5 days, respectively. In addition, our work showed that Symbiodinium bioconcentrated (63)Ni exponentially, with a vol/vol concentration factor at steady state (VCFSS) reaching 14,056. However, compilation of our results highlighted that despite efficient bioconcentration of (63)Ni in Symbiodinium, their contribution to the whole (63)Ni accumulation in coral nubbins represents less than 7%, suggesting that other biologically controlled processes occur in coral host allowing such efficient bioconcentration in coral tissues. PMID:27192479
Uptake, distribution and elimination of {sup 54}Mn(II) in the brown trout (Salmo trutta)
Rouleau, C.; Tjaelve, H.; Gottofrey, J.; Pelletier, E.
Brown trout (Salmo trutta) were exposed to water containing 0.1 {mu}g {center_dot} L{sup {minus}1} (1.8 nmol {center_dot} L{sup {minus}1}) of {sup 54}Mn(II) for 1, 3, or 6 weeks. Additional trout were exposed for 3 weeks and allowed to depurate for 1 or 3 weeks. Both the uptake and the organ distribution of manganese (Mn) were determined by gamma counting and whole-body autoradiography. Steady-state concentration, C{sub SS}, and biological half-life, t{sub 1/2}, were calculated. The whole-body Mn concentration reached after 6 weeks of exposure was close to C{sub SS} and t{sub 1/2} was 9.6 d. Manganese concentration in tissues followed the decreasing order liver > viscera without liver and key > gills > skin, fins, bones, and head excluding gills, brain, and eyes > kidney {approx} epidermal mucus > brain > eyes > muscle. Autoradiograms indicated high Mn concentrations in the pancreatic tissue, skeleton, gastrointestinal mucosa, and olfactory system. Gills, viscera, and eyes were near steady state after 6 weeks of exposure, while the other tissues were not. The depuration rate of total radioactivity was relatively rapid initially as 22% of Mn content was lost during the first week, and became slower in the following 2 weeks. Participation of Mn in enzymatic activities of liver, pancreas, and gastrointestinal mucosa may explain its high uptake in these tissues, whereas accumulation in the skeleton seems to be related to bone formation. The uptake of Mn by way of olfactory system favored its accumulation in the brain of trout. As Mn is known to be neurotoxic, the authors suggest this route of uptake could be of toxicological significance for fish.
Ultra-separation of nickel from copper metal for the measurement of 63Ni by AMS
NASA Astrophysics Data System (ADS)
Marchetti, A. A.; Hainsworth, L. J.; McAninch, J. E.; Leivers, M. R.; Jones, P. R.; Proctor, I. D.; Straume, T.
Measurements of 63Ni (t{1}/{2} = 100 yr) produced by the reaction 63Cu(n,p)63Ni could be used in the assessment of fast-neutron fluence from the Hiroshima atomic bomb. Such measurements would add new information to help resolve the current discrepancy between measured thermal neutron activation values and those calculated with the DS86 dosimetry system. It has been estimated that the 63Ni production at 5 m from the hypocenter was (1.4 ± 0.1) × 107 atoms/g Cu. Because of its sensitivity, accelerator mass spectrometry (AMS) is ideal for measurements at this low level. However, 63Ni has to be separated from large amounts of stable atomic isobar 63Cu (69% of pure Cu). In this study, a procedure is presented for the electrochemical separation of ultra-low amounts of Ni from Cu. The method was developed using samples of electrical Cu wire that were irradiated with fission neutrons from a 252Cf source. The wire samples were electrochemically dissolved in a solution containing 1 mg of Ni carrier. The Cu was selectively deposited on a cathode at controlled potential. Measurements of total Ni after electroseparation indicate ˜ 100% carrier recovery. To prevent Cu contamination, AMS targets were prepared by nickel carbonyl generation. The AMS results show a successful quantitative separation of ˜ 107 atoms of 63Ni from 2-20 g samples of Cu.
252Cf spectrum-averaged cross section for the 63Cu(n, p)63Ni reaction
NASA Astrophysics Data System (ADS)
Imamura, M.; Shibata, T.; Shibata, S.; Ohkubo, T.; Satoh, S.; Nogawa, N.
The 63Ni produced by the 63Cu(n, p)63Ni reaction provides a unique measure to estimate the fast-neutron fluence of the Hiroshima/Nagasaki atomic bomb. In the similarity of the fission neutron spectrum of 252Cf to that of 235U, we have measured activation cross sections of the 63Cu(n, p)63Ni reaction averaged for the 252Cf fission spectrum.
Assessing deposition levels of 55Fe, 60Co and 63Ni in the Ignalina NPP environment.
Gudelis, A; Druteikiene, R; Luksiene, B; Gvozdaite, R; Nielsen, S P; Hou, X; Mazeika, J; Petrosius, R
Two RBMK-1500 reactor units operated in Lithuania in the 1987-2004 period (one of them was stopped for decommissioning in 2004). This study presents a preliminary investigation of surface deposition density levels of (55)Fe and (63)Ni in moss samples collected in the close vicinity of the Ignalina NPP. Non-destructive analysis by the HPGe gamma-spectrometry was followed by radiochemical separation. Radiochemical analysis was based on anion-exchange and extraction chromatography. (55)Fe and (63)Ni activities were measured by liquid scintillation counting (LSC). The results indicate that the deposition values of (55)Fe are generally higher than those of (60)Co and (63)Ni. PMID:18818005
Iron and zinc concentrations and /sup 59/Fe retention in developing fetuses of zinc-deficient rats
Rogers, J.M.; Loennerdal, B.H.; Hurley, L.S.; Keen, C.L.
Because disturbances in iron metabolism might contribute to the teratogenicity of zinc deficiency, we examined the effect of zinc deficiency on fetal iron accumulation and maternal and fetal retention of /sup 59/Fe. Pregnant rats were fed from mating a purified diet containing 0.5, 4.5 or 100 micrograms Zn/g. Laparotomies were performed on d 12, 16, 19 and 21 of gestation. Maternal blood and concepti were analyzed for zinc and iron. Additional groups of dams fed 0.5 or 100 micrograms Zn/g diet were gavaged on d 19 with a diet containing /sup 59/Fe. Six hours later maternal blood and tissues, fetuses and placentas were counted for /sup 59/Fe. Maternal plasma zinc, but not iron, concentration was affected by zinc deficiency on d 12. Embryo zinc concentration on d 12 increased with increasing maternal dietary zinc, whereas iron concentration was not different among groups. On d 16-21 plasma iron was higher in dams fed 0.5 micrograms Zn/g diet than in those fed 4.5 or 100 micrograms/g, whereas plasma zinc was lower in dams fed 0.5 or 4.5 micrograms Zn/g than in those fed 100 micrograms Zn/g diet. On d 19 zinc concentration in fetuses from dams fed 0.5 micrograms/g zinc was not different from that of those fed 4.5 micrograms/g zinc, and iron concentration was higher in the 0.5 microgram Zn/g diet group. The increase in iron concentration in zinc-deficient fetuses thus occurs too late to be involved in major structural teratogenesis. Although whole blood concentration of /sup 59/Fe was not different in zinc-deficient and control dams, zinc-deficient dams had more /sup 59/Fe in the plasma fraction.
Low-level measurement of 63Ni by means of accelerator mass spectrometry
NASA Astrophysics Data System (ADS)
Rugel, G.; Arazi, A.; Carroll, K. L.; Faestermann, T.; Knie, K.; Korschinek, G.; Marchetti, A. A.; Martinelli, R. E.; McAninch, J. E.; Rühm, W.; Straume, T.; Wallner, A.; Wallner, C.
The radionuclide 63Ni (T1/2=100.1 a) has been proposed as a fluence monitor for fast neutrons in copper samples from Hiroshima. Accelerator mass spectrometry (AMS) represents a powerful tool for the detection of this radionuclide, provided the isobaric interference of 63Cu can be sufficiently suppressed. In this paper, we report the first results from a study on the 63Cu background observed in different sets of control samples, and in a 127-year-old environmental copper sample which was directly exposed to cosmic radiation for about 80 years. The 63Ni/Ni ratios measured in the blank samples range up to about 2 × 10-13 corresponding to concentrations of a few times 10463Ni atoms/g Cu. These results provide information on the overall background of the applied methodology and, thus, on the possible sensitivity of 63Ni measurements in copper samples by means of AMS. In the environmental sample, a 63Ni concentration of (1.0 ± 0.3) × 10563Ni atoms/g Cu was observed which is not significantly different from the results obtained on commercially available copper material. A similar concentration would be expected in a copper sample located 1300 m from the hypocenter of the Hiroshima atomic bomb.
59Fe(n,g)60Fe and 60Fe(n,g)61Fe Reaction Rates from Local Systematics
Kelley, K; Hoffman, R D; Drake, M
We present modeled neutron capture cross sections relevant to stellar production of {sup 60}Fe. Systematics for the input parameters required by the Hauser-Feshbach statistical model are developed based on measured data in the local region of the isotopic plane (20 {le} Z {le} 29, 43 {le} A {le} 65). These parameters and used to calculate reaction cross sections and rates for select target isotopes. Modeled cross sections are compared to experimental data where available. The {sup 59}Fe(n,{gamma}){sup 60}Fe and {sup 60}Fe(n, {gamma}){sup 61}Fe rates are compared to previous calculations. A brief discussion of errors related to the modeling is provided. We conclude by investigating the sensitivity of stellar production of {sup 26}Al and {sup 60}Fe to the {sup 59}Fe(n,{gamma}){sup 60}Fe and {sup 60}Fe(n,{gamma})61Fe reaction rates using a single zone model.
Stable and high-yielding intrinsic (59) Fe-radiolabeling of the intravenous iron preparations Monofer and Cosmofer.
Jensen, Andreas I; Severin, Gregory W; Andreasen, Hans B; Rasmussen, Palle H
Commercial iron supplements Monofer(®) and Cosmofer(®) were intrinsically radiolabeled with (59) Fe for the purpose of tracing iron absorption in vivo. Optimized procedures aimed at introducing (59) Fe into the macromolecular construct in a form that was as chemically equivalent to the matrix iron as possible. This was determined by challenging the labeled constructs with diethylenetriaminepentaacetic acid (DTPA) followed by separation by size-exclusion and measurements of radioactivity and iron in the eluted fractions. The final procedures were simple and involved heating aqueous dispersions of the supplements in the presence of [(59) Fe]FeCl3 for 24 h at 95 °C for Monofer, and 85 °C for Cosmofer, resulting in radiochemical yields greater than 94%. High performance size exclusion chromatography, UV-VIS spectroscopy, and dynamic light scattering were used to show that the supplements remained unchanged after radiolabeling, underscoring the applicability of the methodology for radiolabeling commercial iron preparations. PMID:27311359
Emanation of 54Mn and 57Co impurity "hot" atoms from metal iron upon annealing the radiation damage
NASA Astrophysics Data System (ADS)
Alekseev, I.
Irradiation of metallic iron with intense (10 μА) beams of deuterons (Ed - 9.0/8.2 MeV; fluence, 1.0×1022 m-2) is accompanied by the formation of a metastable γ-phase in the bulk of metal. Short annealing at low temperature (at (873±5) K for 10 min) of irradiated samples leads to a degradation of the γ-phase of iron, to a reversion of the irradiated metal into the low-temperature state of α-Fe, which is typical at room temperature, and is followed by a higher emanation of 54Mn atoms into the gaseous phase (almost by two orders of magnitude higher as compared to the vapor pressure values under this temperature). The results that are principally coincident with the ones given above (accelerated transport and subsequent excessive emanation of the "hot" atoms into the gaseous phase) have been obtained for 57Co as well.
Absorption and biological half-life in humans of intrinsic and extrinsic sup 54 Mn tracers from foods of plant origin
Johnson, P.E.; Lykken, G.I.; Korynta, E.D. )
Absorption and biological half-life of {sup 54}Mn were measured in adult men and women fed foods labeled intrinsically or extrinsically with {sup 54}Mn. Each subject consumed a series of three test meals consisting of a food labeled intrinsically, a food labeled extrinsically or MnCl{sub 2} (control) served in random order. The foods tested were lettuce, spinach, wheat and sunflower seeds. Lettuce meals and their controls contained 9.65 mumol Mn; other meals contained 22.50 mumol Mn. In addition to the test food or MnCl{sub 2}, each meal consisted of vegetable oil (5 g), salt (NaCl, 0.15 g) and crackers (10 g), which provided 0.55 mumol Mn. There were no differences in percentage of Mn absorption or biological half-life of {sup 54}Mn for any of the intrinsically/extrinsically labeled food pairs. Absorption of {sup 54}Mn from MnCl{sub 2} (8.90%) was greater than from lettuce (5.20%), spinach (3.81%), wheat (2.16%) or sunflower seeds (1.71%), but the biological half-life did not vary with the source of Mn. Absorption of {sup 54}Mn from lettuce was significantly (P less than 0.05) greater than from wheat or sunflower seeds. Although the Mn dose in the test meal was less for lettuce than for the other foods, there was no difference in Mn absorption from MnCl{sub 2} between the subjects fed lettuce and subjects fed other foods. There was no correlation of either {sup 54}Mn absorption or biological half-life with whole blood or plasma Mn.
Solution chemistry effects on sorption behavior of radionuclide 63Ni(II) in illite-water suspensions
NASA Astrophysics Data System (ADS)
Hu, Baowei; Cheng, Wen; Zhang, Hui; Yang, Shitong
In this work, a naturally occurring illite was characterized by using FTIR and XRD to determine its chemical constituents and crystal structure. A series of batch experiments were carried out to investigate the effect of various environmental factors such as contact time, pH, ionic strength, foreign ions, coexisting humic substances and temperature on the sorption behavior of illite towards radionuclide 63Ni(II). The sorption of 63Ni(II) on illite was strongly dependent on pH and ionic strength. A positive effect of HA/FA on 63Ni(II) sorption was found at pH < 6.5, whereas a negative effect was observed at pH > 6.5. The Langmuir, Freundlich, and D-R models were used to simulate the sorption isotherms of 63Ni(II) at three different temperatures of 293, 313 and 333 K. The thermodynamic parameters (Δ H0, Δ S0 and Δ G0) of 63Ni(II) sorption on illite were calculated from the temperature dependent sorption isotherms, and the results indicated that the sorption of 63Ni(II) on illite was endothermic and spontaneous. At low pH, the sorption of 63Ni(II) was dominated by outer-sphere surface complexation and ion exchange with Na +/H + on illite surfaces, whereas inner-sphere surface complexation was the main sorption mechanism at high pH. From the experimental results, it is possible to conclude that illite has good potentialities for cost-effective treatments of 63Ni(II)-contaminated wastewaters.
A measurement of the beta spectrum of 63Ni using a new type of cryogenic detector
NASA Astrophysics Data System (ADS)
Gaistkell, R. J.; Angrave, L. C.; Booth, N. E.; Hahn, A. D.; Salmon, G. L.; Swift, A. M.
A precision measurement of the beta spectrum of 63Ni has been performed using a new type of cryogenic particle detector. This is the first nuclear physics experiment using this technique, and we discuss the principles of the method, its advantages and its shortcomings. Careful studies of detector stability, calibration, pulse pile-up and systematics have made it possible to collect large numbers of events (∼ 10 8) over long periods (∼ 28 days). The measurement is consistent with no 17 keV/c 2 neutrino admixture, giving a preferred value of (-0.05 ± 0.31)%.
Measurement of {sup 63}Ni and {sup 59}Ni by accelerator mass spectrometry using characteristic projectile x-rays
McAninch, J.E.; Hainsworth, L.J.; Marchetti, A.A.
The long-lived isotopes of nickel ({sup 59}Ni, {sup 63}Ni) have current and potential use in a number of applications including cosmic radiation studies, biomedical tracing, characterization of low-level radioactive wastes, and neutron dosimetry. Methods are being developed at LLNL for the routine detection of these isotopes by AMS. One intended application is in Hiroshima dosimetry. The reaction {sup 63}Cu(n,p){sup 63}Ni has been identified as one of a small number of reactions which might be used for the direct determination of the fast neutron fluence emitted by the Hiroshima bomb. AMS measurement of {sup 63}Ni(t{sub 1/2} = 100 y) requires the chemical removal of {sup 63}Cu, which is a stable isobar of {sup 63}Ni. Following the electrochemical separation of Ni from gram-sized copper samples, the Cu concentration is further lowered to < 2 x 10{sup -8} (Cu/Ni) using the reaction of Ni with carbon monoxide to form the gas Ni(CO){sub 4}. The Ni(CO){sub 4} is thermally decomposed directly in sample holders for measurement by AMS. After analysis in the AMS spectrometer, the ions are identified using characteristic projectile x-rays, allowing further rejection of remaining {sup 63}Cu. In a demonstration experiment, {sup 63}Ni was measured in Cu wires (2-20 g) which had been exposed to neutrons from a {sup 252}Cf source. We successfully measured {sup 63}Ni at levels necessary for the measurement of Cu samples exposed near the Hiroshima hypocenter. For the demonstration samples, the Cu content was chemically reduced by a factor of 10{sup 12} with quantitative retention of {sup 63}Ni. Detection sensitivity (3{sigma}) was {approximately}20 fg {sup 63}Ni in 1 mg Ni carrier ({sup 63}Ni/Ni {approx} 2 x 10{sup -11}). Significant improvements in sensitivity are expected with planned incremental changes in the methods. Preliminary results indicate that a similar sensitivity is achievable for {sup 59}Ni (t{sub 1/2} = 10{sup 5} y).
Measurement of 63Ni and 59Ni by accelerator mass spectrometry using characteristic projectile X-rays
NASA Astrophysics Data System (ADS)
McAninch, J. E.; Hainsworth, L. J.; Marchetti, A. A.; Leivers, M. R.; Jones, P. R.; Dunlop, A. E.; Mauthe, R.; Vogel, J. S.; Proctor, I. D.; Straume, T.
The long-lived isotopes of nickel (59Ni, 63Ni) have current and potential use in a number of applications including cosmic radiation studies, biomedical tracing, characterization of low-level radioactive wastes, and neutron dosimetry. Methods are being developed at LLNL for the routine detection of these isotopes by AMS. One intended application is in Hiroshima dosimetry. The reaction 63Cu(n,p)63Ni has been identified as one of a small number of reactions which might be used for the direct determination of the fast neutron fluence emitted by the Hiroshima bomb. AMS measurement of 63Ni (t{1}/{2} = 100 y) requires the chemical removal of 63Cu, which is a stable isobar of 63Ni. Following the electrochemical separation of Ni from gram-sized copper samples, the Cu concentration is further lowered to < 2 × 10-8 ({Cu}/{Ni}) using the reaction of Ni with carbon monoxide to form the gas Ni(CO)4. The Ni(CO)4 is thermally decomposed directly in sample holders for measurement by AMS. After analysis in the AMS spectrometer, the ions are identified using characteristic projectile X-rays, allowing further rejection of remaining 63Cu. In a demonstration experiment, 63Ni was measured in Cu wires (2-20 g) which had been exposed to neutrons from a 252Cf source. We successfully measured 63Ni at levels necessary for the measurement of Cu samples exposed near the Hiroshima hypocenter. For the demonstration samples, the Cu content was chemically reduced by a factor of 1012 with quantitative retention of 63Ni. Detection sensitivity (3σ) was ˜ 20 fg 63Ni in 1 mg Ni carrier ({63Ni}/{Ni} ≈ 2 × 10-11). Significant improvements in sensitivity are expected with planned incremental changes in the methods. Preliminary results indicate that a similar sensitivity is achievable for 59Ni (t{1}/{2} = 105 y). Initial work has been undertaken on the application of this isotope as a biomedical tracer in living systems.
Neutron-induced 63Ni activity and microscopic observation of copper samples exposed to the Hiroshima atomic bomb
NASA Astrophysics Data System (ADS)
Shizuma, Kiyoshi; Endo, Satoru; Shinozaki, Kenji; Fukushima, Hiroshi
Fast neutron activation data for 63Ni in copper samples exposed to the Hiroshima atomic bomb are important in evaluating neutron doses to the survivors. Up to until now, accelerator mass spectrometry and liquid scintillation counting methods have been applied in 63Ni measurements and data were accumulated within 1500 m from the hypocenter. The slope of the activation curve versus distance shows reasonable agreement with the calculation result, however, data near the hypocenter are scarce. In the present work, two copper samples obtained from the Atomic bomb dome (155 m from the hypocenter) and the Bank of Japan building (392 m) were utilized in 63Ni beta-ray measurement with a Si surface barrier detector. Additionally, microscopic observation of the metal surfaces was performed for the first time. Only upper limit of 63Ni production was obtained for copper sample of the Atomic bomb dome. The result of the 63Ni measurement for Bank of Japan building show reasonable agreement with the AMS measurement and to fast neutron activation calculations based on the Dosimetry System 2002 (DS02) neutrons.
Identification of 63Ni and 60Co produced in a steel sample by thermal neutrons from the Hiroshima atomic bomb
NASA Astrophysics Data System (ADS)
Shizuma, K.; Iwatani, K.; Hasai, H.; Oka, T.; Hoshi, M.; Shibata, S.; Imamura, M.; Shibata, T.
Long-lived residual radioactivity 63Ni produced by the (n, γ) reaction was detected for the first time from a steel plate sampled at near the hypocenter of the Hiroshima atomic bomb. Nickel and cobalt were chemically separated and enriched from the steel sample. Low energy beta rays of 63Ni were measured with a low-background liquid scintillation counter and gamma-rays of 60Co were measured with a low background Ge detector. Specific activities were determined as 0.0063±0.0004 Bq mg -1 for {63Ni}/{Ni} and 8.70±0.46 Bq mg -1 for {60Co}/{Co} at the time of the bomb explosion. Comparisons with the calculated yield based on the current dosimetry system DS86 neutrons were also given.
Accelerator mass spectrometry of 63Ni using a gas-filled magnet at the Munich Tandem Laboratory
NASA Astrophysics Data System (ADS)
Rugel, G.; Faestermann, T.; Knie, K.; Korschinek, G.; Marchetti, A. A.; McAninch, J. E.; Rühm, W.; Straume, T.; Wallner, C.
The detection of 63Ni ( T1/2=100.1 yr) by means of accelerator mass spectrometry (AMS) using a gas-filled magnet (GFM) is described. The experimental setup includes a dedicated ion source, a 14 MV MP tandem, a GFM and a multi-anode ionization chamber. First results indicate a background level of 63Ni/Ni ratios as low as 2×10 -14. This sensitivity will allow - for the first time ever - to detect 63Ni induced by fast neutrons in copper samples from Hiroshima and Nagasaki, even for distances beyond 1500 m from the hypocenters. Thus, it will be possible to reconstruct experimentally the neutron doses of the A-bomb survivors from Hiroshima and Nagasaki.
The β-decay rates of 59Fe isotopes in shell burning environments and their influences on the production of 60Fe in massive star
NASA Astrophysics Data System (ADS)
Li, K.; Lam, Y. H.; Qi, C.; Tang, X.; Zhang, N.
The experimental B(GT) strengths of the 59Fe excited states were employed to determine the transition strengths which greatly contribute 59Fe stellar β-decay at typical carbon shell burning temperature. The result has been compared with the theoretical rates FFN (Fuller-Fowler-Newman) and LMP (Langanke&Martinez-Pinedo). Impact of the newly determined rate on the synthesis of cosmic γ emitter 60Fe has also been studied using one-zone model calculation. Our results show 59Fe stellar β-decay rate plays an important role in the 60Fe nucleosynthesis. However the uncertainty of the decay rate is rather large due to the error of B(GT) strength that requires further studies.
Simultaneous measurement of 59Fe and 51Cr in iron absorption studies using a whole-body scanner with mobile shielding.
Marx, J J; van den Beld, B; van Dongen, R; Strackee, L H
A whole-body scanner is described with a mobile shadow shield which affords a considerable reduction in space. The scanner has two NaI(T1) scintillation crystals of 4 x 6", placed at opposite sites of the subject. Background radiation, efficiency and geometric qualities made the scanner very useful for clinical whole-body counting. The equipment was used in iron absorption studies using a double isotope technique with 59Fe and 51Cr. After ingestion of an oral test dose total body kinetics of 59Fe and 51Cr was followed up to 60 days in 4 volunteers. Between days 3 and 10 the 51Cr, which was used as an non-absorbable indicator, had left the body completely. The 59Fe reached a constant value not before day 10, indicating that iron retention cannot be measured before that time. From repeated measurement of 59Fe and 51Cr directly after ingestion until the first defaecation it could be deduced that the coefficient of variation for 59Fe was less than 1.5% with a scanning time of 600 sec, and for 51Cr less than 5%. Extreme variations in geometry, such as measurement of the activity in a beaker and of the same amount after ingestion in the body, yielded practically the same value for 59Fe. The double isotope technique made it possible to measure not only iron retention but also mucosal uptake and mucosal transfer of iron. It is pointed out that measurement of the last two parameters of iron absorption is not possible in patients with serious obstipation or with very low mucosal uptake values. PMID:6780983
Tracer diffusion of /sup 60/Co and /sup 63/Ni in amorphous NiZr alloy
Hoshino, K.; Averback, R.S.; Hahn, H.; Rothman, S.J.
Tracer diffusion of /sup 60/Co and /sup 63/Ni in equiatomic amorphous NiZr alloy in the temperature range between 486 and 641/sup 0/K can be described by: D/sub Co/sup */ = 3.7 x 10/sup -7/ exp(-(135 +- 14) kJ mole/sup -1//RT) m/sup 2//sec and D/sub Ni//sup */ = 1.7 x 10/sup -7/ exp(-(140 +- 9) kJ mole/sup -1//RT) m/sup 2//sec. The values of D/sub Ni//sup */ are in reasonable agreement with those measured by the Rutherford backscattering technique. The measured diffusivities were independent of time, indicating that no relaxation took place during diffusion. 27 refs., 2 tabs.
Neutron capture cross section of unstable 63Ni: implications for stellar nucleosynthesis.
Lederer, C; Massimi, C; Altstadt, S; Andrzejewski, J; Audouin, L; Barbagallo, M; Bécares, V; Bečvář, F; Belloni, F; Berthoumieux, E; Billowes, J; Boccone, V; Bosnar, D; Brugger, M; Calviani, M; Calviño, F; Cano-Ott, D; Carrapiço, C; Cerutti, F; Chiaveri, E; Chin, M; Colonna, N; Cortés, G; Cortés-Giraldo, M A; Diakaki, M; Domingo-Pardo, C; Duran, I; Dressler, R; Dzysiuk, N; Eleftheriadis, C; Ferrari, A; Fraval, K; Ganesan, S; García, A R; Giubrone, G; Gómez-Hornillos, M B; Gonçalves, I F; González-Romero, E; Griesmayer, E; Guerrero, C; Gunsing, F; Gurusamy, P; Jenkins, D G; Jericha, E; Kadi, Y; Käppeler, F; Karadimos, D; Kivel, N; Koehler, P; Kokkoris, M; Korschinek, G; Krtička, M; Kroll, J; Langer, C; Leeb, H; Leong, L S; Losito, R; Manousos, A; Marganiec, J; Martínez, T; Mastinu, P F; Mastromarco, M; Meaze, M; Mendoza, E; Mengoni, A; Milazzo, P M; Mingrone, F; Mirea, M; Mondelaers, W; Paradela, C; Pavlik, A; Perkowski, J; Pignatari, M; Plompen, A; Praena, J; Quesada, J M; Rauscher, T; Reifarth, R; Riego, A; Roman, F; Rubbia, C; Sarmento, R; Schillebeeckx, P; Schmidt, S; Schumann, D; Tagliente, G; Tain, J L; Tarrío, D; Tassan-Got, L; Tsinganis, A; Valenta, S; Vannini, G; Variale, V; Vaz, P; Ventura, A; Versaci, R; Vermeulen, M J; Vlachoudis, V; Vlastou, R; Wallner, A; Ware, T; Weigand, M; Weiß, C; Wright, T J; Zugec, P
The 63Ni(n,γ) cross section has been measured for the first time at the neutron time-of-flight facility n_TOF at CERN from thermal neutron energies up to 200 keV. In total, capture kernels of 12 (new) resonances were determined. Maxwellian averaged cross sections were calculated for thermal energies from kT=5-100 keV with uncertainties around 20%. Stellar model calculations for a 25M⊙ star show that the new data have a significant effect on the s-process production of 63Cu, 64Ni, and 64Zn in massive stars, allowing stronger constraints on the Cu yields from explosive nucleosynthesis in the subsequent supernova. PMID:23383895
Sorption properties of new composite materials suitable for radioanalytical determination of 59Ni and 63Ni
NASA Astrophysics Data System (ADS)
Fišera, O.; Šebesta, F.
Results of the study of new and cheaper composite materials for selective separation and radioanalytical determination of radionickel (59,63Ni) in radioactive waste are presented in this work. Chelating agents dimethylglyoxime (DMG) and diphenylglyoxime (DPG) as active components were immobilized in porous matrix of binding polymer polyacrylonitrile (PAN). Sorption properties of these materials were compared with commercial Ni Resin (Eichrom Technologies, USA). Weight distribution ratios, sorption kinetics and operating capacities were investigated during the experiments performed. The highest weight distribution ratios were found for the material DPG-PAN. The sorbent DMG-PAN has the highest operating capacity. The fastest kinetics of nickel sorption was determined for the Ni Resin. Elution of nickel with nitric acid solution allows subsequent and direct determination of radionickel by liquid scintillation counting.
Determination of 63Ni and 59Ni in spent ion-exchange resin and activated charcoal from the IEA-R1 nuclear research reactor.
Taddei, M H T; Macacini, J F; Vicente, R; Marumo, J T; Sakata, S K; Terremoto, L A A
A radiochemical method has been adapted to determine (59)Ni and (63)Ni in samples of radioactive wastes from the water cleanup system of the IEA-R1 nuclear research reactor. The process includes extraction chromatographic resin with dimethylglyoxime (DMG) as a functional group. Activity concentrations of (59)Ni and (63)Ni were measured, respectively, by X-ray spectrometry and liquid scintillation counting, whereas the chemical yield was determined by ICP-OES. The average ratio of measured activity concentrations of (63)Ni and (59)Ni agree well with theory. PMID:23524230
Reduction of cesium concentration in ovine tissues following treatment with Prussian Blue labeled with {sup 59}Fe
Ioannides, K.G.; Karamanis, D.T.; Stamoulis, K.C.
The effectiveness of Prussian Blue in reducing the radiocesium contamination in ovine tissues was investigate. Five ewes were fed {sup 137}Cs-contaminated wheat for 30 d. When the {sup 137}Cs concentration in milk had reached equilibrium, one animal, serving as the control, was slaughtered and the activity in its tissues was measured. Two ewes were offered daily 1 g of Prussian Blue labeled with {sup 59}Fe in the Fe(III) position, outside the complex anion. One week after the administration of Prussian Blue, these animals were slaughtered, 1 wk apart, and the level of {sup 137}Cs in their tissues was measured. Comparing the concentration of {sup 137}Cs in the blood and tissues of the Prussian Blue treated animals to the corresponding concentrations measured in the control, a considerable reduction in the measured in the control, a considerable reduction in the radiocesium activity concentration is observed. However, {sup 137}Cs concentrations are maintained at non-zero (about 20%) values in the first 22 wk after the administration of Prussian Blue. This observation can be attributed to the fact that most of {sup 137}Cs binds to Prussian Blue in the animals` digestive tracts and the measured activity concentrations follow the elimination of cesium from tissues. Using a two-compartment mathematical model, we can predict the level of {sup 137}Cs in tissue, following the administration of Prussian Blue. Labeling Prussian Blue in the Fe(III)-position resulted in the measurement of a (2.4 {plus_minus} 0.02) % retention of Fe(III) in sheep. 23 refs., 2 figs., 5 tabs.
Temperature effect on betavoltaic microbatteries based on Si and GaAs under 63Ni and 147Pm irradiation
NASA Astrophysics Data System (ADS)
Wang, Hao; Tang, Xiao-bin; Liu, Yun-Peng; Xu, Zhi-Heng; Liu, Min; Chen, Da
The effect of temperature on the output performance of four different types of betavoltaic microbatteries was investigated experimental and theoretical. Si and GaAs were selected as the energy conversion devices in four types of betavoltaic microbatteries, and 63Ni and 147Pm were used as beta sources. Current density-voltage curves were determined at a temperature range of 213.15-333.15 K. A simplified method was used to calculate the theoretical parameters of the betavoltaic microbatteries considering the energy loss of beta particles for self-absorption of radioactive source, the electron backscatter effect of different types of semiconductor materials, and the absorption of dead layer. Both the experimental and theoretical results show that the short-circuit current density increases slightly and the open-circuit voltage (VOC) decreases evidently with the increase in temperature. Different combinations of energy conversion devices and beta sources cause different effects of temperature on the microbatteries. In the approximately linear range, the VOC sensitivities caused by temperature for 63Ni-Si, 63Ni-GaAs, 147Pm-Si, and 147Pm-GaAs betavoltaic microbatteries were -2.57, -5.30, -2.53, and -4.90 mV/K respectively. Both theoretical and experimental energy conversion efficiency decreased evidently with the increase in temperature.
A method to detect low-level 63Ni activity for estimating fast neutron fluence from the Hiroshima atomic bomb.
Ito, Y; Shibata, T; Imamura, M; Shibata, S; Nogawa, N; Uwamino, Y; Shizuma, K
The Hiroshima and Nagasaki atomic bombs resulted in the worst reported exposure of radiation to the human body. The data of survivors have provided the basis for the risk estimation for ionizing radiation, and thus are widely used as the basis of radiation safety. In this report we have studied a new method to detect the low-level 63Ni activity in copper samples in order to estimate the fast neutron fluence from the Hiroshima atomic bomb. Only 0.8 x 10(-3) Bq g(-1) of 63Ni is expected to be produced by the atomic bomb in a copper sample with the 63Cu(n, p)63Ni reaction at a distance of 500 m from the hypocenter. Our method has the required level of sensitivity for determination of the fast neutron fluence out to distances of at least 500 m, and perhaps as far as 1,000 m. We have already investigated and collected some bomb-irradiated copper samples for further study. PMID:10334579
Comparison of calculated spectra for the interaction of photons in a liquid scintillator. Example of 54Mn 835 keV emission.
Cassette, P; Ahn, G H; Alzitzoglou, T; Aubineau-Lanièce, I; Bochud, F; Garcia Torano, E; Grau Carles, A; Grau Malonda, A; Kossert, K; Lee, K B; Laedermann, J P; Simpson, B R S; van Wyngaardt, W M; Zimmerman, B E
The CIEMAT/NIST and TDCR methods in liquid scintillation counting, initially developed for the activity standardization of pure-beta radionuclides, have been extended to the standardization of electron capture and beta-gamma radionuclides. Both methods require the calculation of the energy spectrum absorbed by the liquid scintillator. For radionuclides emitting X-rays or gamma-rays, when the energy is greater than a few tens of keV the Compton interaction is important and the absorption is not total. In this case, the spectrum absorbed by the scintillator must be calculated using analytical or stochastic models. An illustration of this problem is the standardization of 54Mn, which is a radionuclide decaying by electron capture. The gamma transition, very weakly converted, leads to the emission of an 835 keV photon. The calculation of the detection efficiency of this radionuclide requires the calculation of the energy spectrum transferred to the scintillator after the absorption of the gamma ray and the associated probability of absorption. The validity of the method is thus dependent on the correct calculation of the energy transferred to the scintillator. In order to compare the calculation results obtained using various calculation tools, and to provide the metrology community with some information on the choice of these tools, the LS working group of the ICRM organised a comparison of the calculated absorbed spectra for the 835 keV photon of 54Mn. The result is the spectrum of the energy absorbed by the scintillator per emission of an 835 keV gamma ray. This exercise was proposed for a standard 20 ml LS glass vial and for LS cocktail volumes of 10 and 15 ml. The calculation was done for two different cocktails: toluene and a widely used commercial cocktail, Ultima Gold. The paper describes the results obtained by nine participants using a total of 12 calculation codes. PMID:16600600
(54)Mn Radiotracers Demonstrate Continuous Dissolution and Reprecipitation of Vernadite (δ-MnO2) during Interaction with Aqueous Mn(II).
Elzinga, Evert J
(54)Mn radiotracers were used to assess Mn atom exchange between aqueous Mn(II) and vernadite (δ-MnO2) at pH 5.0. Continuous solid-liquid redistribution of (54)Mn atoms occurred, and systems are near isotopic equilibrium after reaction for 3 months. Despite this extensive exchange, X-ray diffraction and X-ray absorption spectroscopy data showed no major changes in vernadite bulk mineralogy. These results demonstrate that the vernadite-Mn(II) interface is dynamic, with the substrate undergoing continuous dissolution and reprecipitation mediated by aqueous Mn(II) without observable impacts on its mineralogy. Interfacial redox reactions between adsorbed Mn(II) and solid-phase Mn(IV) and Mn(III) are proposed as the main drivers of this process. Interaction between aqueous Mn(II) and structural Mn(III) likely involves interfacial electron transfer coupled with Mn atom exchange. The exchange of aqueous Mn(II) and solid-phase Mn(IV) is more complex and is proposed to result from coupled interfacial comproportionation-disproportionation reactions, where electron transfer from adsorbed Mn(II) to lattice Mn(IV) produces transient Mn(III) species that disproportionate to regenerate aqueous Mn(II) and structural Mn(IV). These findings provide further evidence of the importance of Mn(II)(aq)-MnO2(s) interactions and the attendant production of transient Mn(III) intermediates to the geochemical functioning of phyllomanganates in environments undergoing Mn redox cycling. PMID:27403960
Standardization of the radionuclides (60)Co and (59)Fe by digital 4πβ(PC)-γ(NaI) coincidence counting.
Zhang, Ming; Yao, Shunhe; Liang, Junchen; Liu, Haoran
The digital coincidence counting (DCC) technique has been developed at NIM, China to replace the classical analog coincidence units in the 4πβ-γ counting system. The detector system comprises two NaI (Tl) γ-ray detectors and a 4πβ proportional counter (PC) operated with a mixture of argon and methane at atmospheric pressure in a gas flow arrangement. To update the activity results of radionuclide (60)Co in the KCDB and contribute to the APMP.RI(II)-K2.Fe-59 comparison, (60)Co and (59)Fe dry sources were prepared and measured using the digital 4πβ(PC)-γ(NaI) coincidence system by applying the efficiency extrapolation method. For (60)Co nuclide, the activity concentration value equal to 290.6kBqg(-1) with a relative standard uncertainty of 0.26%, is consistent with the result given by the calibrated ionization chamber. For the nuclide (59)Fe, the activity concentration value at the reference date was 471.7kBqg(-1) with a relative standard uncertainty of 0.34%. This value is in good agreement with the result obtained with the HPGe γ spectrometry, which was calibrated by using a series of standard point sources from PTB. PMID:26651175
Accelerator mass spectrometry of 63Ni at the Munich Tandem Laboratory for estimating fast neutron fluences from the Hiroshima atomic bomb.
Rühm, W; Knie, K; Rugel, G; Marchetti, A A; Faestermann, T; Wallner, C; McAninch, J E; Straume, T; Korschinek, G
After the release of the present dosimetry system DS86 in 1987, measurements have shown that DS86 may substantially underestimate thermal neutron fluences at large distances (>1,000 m) from the hypocenter in Hiroshima. This discrepancy casts doubts on the DS86 neutron source term and, consequently, the survivors' estimated neutron doses. However, the doses were caused mainly by fast neutrons. To determine retrospectively fast neutron fluences in Hiroshima, the reaction 63Cu(n, p)63Ni can be used, if adequate copper samples can be found. Measuring 63Ni (half life 100 y) in Hiroshima samples requires a very sensitive technique, such as accelerator mass spectrometry (AMS), because of the relatively small amounts of 63Ni expected (approximately 10(5)-10(6) atoms per gram of copper). Experiments performed at Lawrence Livermore National Laboratory have demonstrated in 1996 that AMS can be used to measure 63Ni in Hiroshima copper samples. Subsequently, a collaboration was established with the Technical University of Munich in view of its potential to perform more sensitive measurements of 63Ni than the Livermore facility and in the interest of interlaboratory validation. This paper presents the progress made at the Munich facility in the measurement of 63Ni by AMS. The Munich accelerator mass spectrometry facility is a combination of a high energy tandem accelerator and a detection system featuring a gas-filled magnet. It is designed for high sensitivity measurements of long-lived radioisotopes. Optimization of the ion source setup has further improved the sensitivity for 63Ni by reducing the background level of the 63Cu isobar interference by about two orders of magnitude. Current background levels correspond to a ratio of 63Ni/Ni<2x10(-14) and suggest that, with adequate copper samples, the assessment of fast neutron fluences in Hiroshima and Nagasaki is possible for ground distances of up to 1500 m, and--under favorable conditions--even beyond. To demonstrate this
Nuclear level densities in {sup 47}V, {sup 48}V, {sup 49}V, {sup 53}Mn, and {sup 54}Mn from neutron evaporation spectra
Zhuravlev, B. V. Lychagin, A. A.; Titarenko, N. N.; Demenkov, V. G.; Trykova, V. I.
The spectra of neutrons from the (p, n) reactions on {sup 47}Ti, {sup 48}Ti, {sup 49}Ti, {sup 53}Cr, and {sup 54}Cr nuclei were measured in the proton-energy range 7-11 MeV. The measurements were performed with the aid of a fast-neutron spectrometer by the time-of-flight method over the base of the EGP-15 tandem accelerator of the Institute for Physics and Power Engineering (IPPE, Obninsk). Owing to a high resolution and a high stability of the time-of-flight spectrometer used, low-lying discrete levels could be identified reliably along with a continuum section of neutron spectra. An analysis of measured data was performed within the statistical equilibrium and preequilibrium models of nuclear reactions. The relevant calculations were performed by using the exact formalism of Hauser-Feshbach statistical theory supplemented with the generalized model of a superfluid nucleus, the back-shifted Fermi gas model, and the Gilbert-Cameron composite formula for the nuclear level density. The nuclear level densities for {sup 47}V, {sup 48}V, {sup 49}V, {sup 53}Mn, and {sup 54}Mn were determined along with their energy dependences and model parameters. The results are discussed together with available experimental data and recommendations of model systematics.
Sensitivity and uncertainty analysis of the simulation of 123I and 54Mn gamma and X-ray emissions in a liquid scintillation vial.
Bignell, L J; Mo, L; Alexiev, D; Hashemi-Nezhad, S R
Radiation transport simulations of the most probable gamma- and X-ray emissions of (123)I and (54)Mn in a three photomultiplier tube liquid scintillation detector have been carried out. A Geant4 simulation was used to acquire energy deposition spectra and interaction probabilities with the scintillant, as required for absolute activity measurement using the triple to double coincidence ratio (TDCR) method. A sensitivity and uncertainty analysis of the simulation model is presented here. The uncertainty in the Monte Carlo simulation results due to the input parameter uncertainties was found to be more significant than the statistical uncertainty component for a typical number of simulated decay events. The model was most sensitive to changes in the volume of the scintillant. Estimates of the relative uncertainty associated with the simulation outputs due to the combined stochastic and input uncertainties are provided. A Monte Carlo uncertainty analysis of an (123)I TDCR measurement indicated that accounting for the simulation uncertainties increases the uncertainty of efficiency of the logical sum of double coincidence by 5.1%. PMID:20036571
Neutron-induced 63Ni in copper samples from Hiroshima and Nagasaki: a comprehensive presentation of results obtained at the Munich Maier-Leibnitz Laboratory.
Rühm, W; Carroll, K L; Egbert, S D; Faestermann, T; Knie, K; Korschinek, G; Martinelli, R E; Marchetti, A A; McAninch, J E; Rugel, G; Straume, T; Wallner, A; Wallner, C; Fujita, S; Hasai, H; Hoshi, M; Shizuma, K
Those inhabitants of Hiroshima and Nagasaki who were affected by the A-bomb explosions, were exposed to a mixed neutron and gamma radiation field. Few years later about 120,000 survivors of both cities were selected, and since then radiation-induced late effects such as leukemia and solid tumors are being investigated in this cohort. When the present study was initiated, the fast neutron fluences that caused the neutron doses of these survivors had never been determined experimentally. In principle, this would have been possible if radioisotopes produced by fast neutrons from the A-bomb explosions had been detected in samples from Hiroshima and Nagasaki at distances where the inhabitants survived. However, no suitable radioisotope had so far been identified. As a contribution to a large international effort to re-evaluate the A-bomb dosimetry, the concentration of the radionuclide (63)Ni (half-life 100.1 years) has been measured in copper samples from Hiroshima and Nagasaki. These measurements were mainly performed at the Maier-Leibnitz-Laboratory in Munich, Germany, by means of accelerator mass spectrometry. Because the (63)Ni had been produced in these samples by fast A-bomb neutrons via the reaction (63)Cu(n,p)(63)Ni, these measurements allow direct experimental validation of calculated neutron doses to the members of the LSS cohort, for the first time. The results of these efforts have already been published in a compact form. A more detailed discussion of the methodical aspects of these measurements and their results are given in the present paper. Eight copper samples that had been significantly exposed to fast neutrons from the Hiroshima A-bomb explosion were investigated. In general, measured (63)Ni concentrations decreased in these samples with increasing distance to the hypocenter, from 4 x 10(6 ) (63)Ni nuclei per gram copper at 391 m, to about 1 x 10(5 ) (63)Ni nuclei per gram copper at about 1,400 m. Additional measurements performed on three large
Amendments to (63)Ni production calculation for Hiroshima by Takamiya et al. and DS02 fluence data by Egbert et al.
Takamiya, K; Imanaka, T; Egbert, S D; Rühm, W
In a previous paper, Takamiya et al. calculated (63)Ni production in copper samples exposed to the Hiroshima atomic bomb. More specifically, they used their experimental cross-section values of the (63)Cu(n,p)(63)Ni reaction and compared the result with that of the corresponding calculation in the radiation dosimetry system DS02, which used another set of cross-section values. These results were different, and the following two reasons were found: typographical errors in several energy boundary values in the DS02 report that was also used in the calculation by Takamiya et al. and an inappropriate assumption on the cross-section values of the low neutron energy region in the calculation by Takamiya et al. These two issues are described and amended in the present report. PMID:21327808
Aqueous ethanol extraction of dietary soy protein isolate improves sup 59 Fe absorption by the rat from a casein-based test meal
Thompson, D.B. )
A commercial soy protein isolate (SPI) was further processed in an attempt to understand how a diet based on SPI can cause decreased iron retention by the rat from a separately administered casein-based test meal. Groups of eight rats were fed either a casein-based diet or a diet based on SPI. The acid-precipitated SPI was incorporated into diets as such, after neutralization, after 60% (v/v) ethanol extraction and neutralization, or after 60% ethanol exposure and neutralization. All dietary SPI was heat-treated by exposure to steam at 108 degrees C for 30 min. Rats were fed their respective diets, each containing 25 mg Fe/kg, for 13 d, and then all rats were fed a {sup 59}Fe-radiolabeled 2.5-g casein test meal containing 64 micrograms of iron. Ingested radioactivity was determined following the meal, and retained radioactivity over the subsequent 10-d period. Absorption was not distinguishable for groups fed the casein-based (78.3 {plus minus} 3.6%) and the ethanol-extracted, SPI-based diet (80.2 {plus minus} 5.4%). Absorption was lower (P less than 0.01) for groups fed each of the other SPI-based diets: SPI as such (68.3 {plus minus} 8.9%), neutralized SPI (69.8 {plus minus} 5.0%) and ethanol-exposed SPI (67.6 {plus minus} 4.8%). An ethanol-extractable component of SPI may be responsible for decreased iron absorption by animals fed SPI prior to a radiolabeled test meal.
[Problems in the use of radioactively marked bacteria in animal experiments. 1. Labeling of Pasteurella multocida, Pasteurella haemolytica and Salmonella dublin with eH, 14C, 32P, 59Fe, 99mTc, 125J1].
Flossmann, K D; Rohrmann, B; Hubald, J; Finsterbusch, L
Several methods are suggested by which to use the radionuclides 3H, 14C, 32P, 59Fe, 99mTc, and 125J for labelling or doublelabelling of Pasteurella multocida, Pasteurella haemolytica, and Salmonella dublin, with particular reference being made to labelling ofr animal experiments. Suitable radioactive substrates for internal labelling in chemically defined or partially defined nutritive media include 3H-thymin, 3H-thymidine, 14C-glucose, 14C-mannose, 14C-aspartic acid, as well as 3H-uracil, 3H-uridine, 3H-orotic acid, 14C-orotic acid, 59Fe-III-citrate or chloride, and Na2H32PO4. The choise of the nuclide and substrate should by governed by the problem at hand. PMID:849104
Measurement of the 58Ni(n,t)56Co, 59Co(n,p)59Fe, and 63Cu(n,{alpha})60Co Reaction Cross Sections from 14 to 20 MeV
Semkova, V.; Plompen, A.J.M.; Smith, D.L.
Neutron activation cross sections for the 63Cu(n,{alpha})60Co, 59Co(n,p)59Fe, and 58Ni(n,t)56Co reactions were measured in the energy range from 13 to 21 MeV. The irradiations were carried out at the 7-MV Van de Graaff accelerator at IRMM, Geel. Quasi-monoenergetic neutrons were produced via the 3H(d,n)4He reaction at 1-, 2-, 3-, and 4-MeV incident deuteron energy. All reaction cross sections measured in the present work are referenced to the 27Al(n,{alpha})24Na standard reaction cross section. Neutron flux spectra were determined by an activation spectral index method in combination with TOF spectrum measurements. Standard {gamma}-ray spectrometry was employed for the measurement of radioactivity. The measured results are compared with work by other authors, TALYS-0.57 and EMPIRE-II model calculations, and current evaluated data files. The new results contribute substantially to the experimental database of the measured reactions. Recommendations are provided for the best evaluations for the 59Co(n,p)59Fe, and 63Cu(n,{alpha})60Co reactions. For the 58Ni(n,t)56Co reaction no current evaluation is in good agreement with all available data. For this reaction further measurements would help to guide new modeling efforts.
Improved Analytical Performance of Negative 63Ni Ion Mobility Spectrometry for On-line Measurement of Propofol Using Dichloromethane as Dopant
NASA Astrophysics Data System (ADS)
Zhou, Qinghua; Hua, Lei; Wang, Changsong; Li, Enyou; Li, Haiyang
On-line monitoring of propofol in exhaled air is a potential way to evaluate the anaesthesia depth for patients during surgery. In this study, a negative 63Ni ionization high resolution ion mobility spectrometer with Bradbury-Nielsen-Gate-Grid structure was built to measure propofol with reactant ions Cl-(H2O) n using dichloromethane as dopant. Instead of forming three propofol ions (M - H)-, M · O2 -, and (M2 - H)- with reactant ions O2 -(H2O) n , only product ion M · Cl- was produced when introducing dichloromethane gas. The peak-to-peak resolution ( R p-p) between reactant ions Cl-(H2O) n and product ion M · Cl- was 17.4, which was 1.6 times larger than that between O2 -(H2O) n and product ion. Furthermore, the linear response range using reactant ions Cl-(H2O) n was 3.5 times wider than that obtained with reactant ions O2 -(H2O) n .
Selective uptake, distribution, and redistribution of (109)Cd, (57)Co, (65)Zn, (63)Ni, and (134)Cs via xylem and phloem in the heavy metal hyperaccumulator Solanum nigrum L.
Wei, Shuhe; Anders, Iwona; Feller, Urs
The focus of this article was to explore the translocation of (109)Cd, (57)Co, (65)Zn, (63)Ni, and (134)Cs via xylem and phloem in the newly found hyperaccumulator Solanum nigrum L. Two experiments with the uptake via the roots and transport of (109)Cd, (57)Co, and (65)Zn labeled by roots, and the redistribution of (109)Cd, (65)Zn, (57)Co, (63)Ni, and (134)Cs using flap label in S. nigrum in a hydroponic culture with a standard nutrient solution were conducted. The results showed that (109)Cd added for 24 h to the nutrient medium of young plants was rapidly taken up, transferred to the shoot, and accumulated in the cotyledons and the oldest leaves but was not efficiently redistributed within the shoot afterward leading to a rather low content in the fruits. In contrast, (57)Co was more slowly taken up and released to the shoot, but afterward, this element was redistributed from older leaves to younger leaves and maturing fruits. (65)Zn was rapidly taken up and transferred to the shoot (mainly to the youngest leaves and not to the cotyledons). Afterward, this radionuclide was redistributed within the shoot to the youngest organs and finally accumulated in the maturing fruits. After flap labeling, all five heavy metals tested ((109)Cd, (57)Co, (65)Zn, (63)Ni, (134)Cs) were exported from the labeled leaf and redistributed within the plant. The accumulation in the fruits was most pronounced for (63)Ni and (65)Zn, while a relatively high percentage of (57)Co was finally found in the roots. (134)Cs was roughly in the middle of them. The transport of (109)Cd differed from that previously reported for wheat or lupin and might be important for the potential of S. nigrum to hyperaccumulate cadmium. PMID:24604268
A compendium on the NIST radionuclide assays of the massic activity of {sup 63}Ni and {sup 55}Fe solutions used for an international intercomparison of liquid scintillation spectrometry techniques
Colle, R.; Zimmerman, B.E.
The National Institute of Standards and Technology recently participated in an international measurement intercomparison for {sup 63}Ni and {sup 55}Fe, which was conducted among principal national radionuclidic metrology laboratories. The intercomparison was sponsored by EUROMET, and was primarily intended to evaluate the capabilities of liquid scintillation (LS) spectrometry techniques for standardizing nuclides that decay by low-energy {beta}-emission (like {sup 63}Ni) and by low-Z (atomic number) electron capture (like {sup 55}Fe). The intercomparison findings exhibit a very good agreement for {sup 63}Ni among the various participating laboratories, including that for NIST, which suggests that the presently invoked LS methodologies are very capable of providing internationally-compatible standardizations for low-energy {beta}-emitters. The results for {sup 55}Fe are in considerably poorer agreement, and demonstrated the existence of several unresolved problems. It has thus become apparent that there is a need for the various international laboratories to conduct rigorous, systematic evaluations of their LS capabilities in assaying radionuclides that decay by low-Z electron capture.
Synthesis and electrochemical performance of high-capacity 0.34Li{sub 2}MnO{sub 3}·0.66LiMn{sub 0.63}Ni{sub 0.24}Co{sub 0.13}O{sub 2} cathode materials using a Couette–Taylor reactor
Choi, Mansoo; Kim, Hyun-Soo; Kim, Jik-Soo; Park, Suk-Joon; Lee, Young Moo; Jin, Bong-Soo
Highlights: • The cathode material synthesized by co-precipitation using a Couette–Taylor reactor. • The first and second discharge capacities were measured to be 311 and 307 mA h g{sup −1}. • The material has an excellent rate capability. - Abstract: The 0.34Li{sub 2}MnO{sub 3}·0.66LiMn{sub 0.63}Ni{sub 0.24}Co{sub 0.13}O{sub 2} cathode material for the Li-ion battery is synthesized by co-precipitation using a Couette–Taylor reactor. Particle size analysis (PSA) and a field emission-scanning electron microscopy (FE-SEM) images show that the obtained precursor and cathode material exhibit a narrow particle size distribution and spherical shape. The structure and composition of the 0.34Li{sub 2}MnO{sub 3}·0.66LiMn{sub 0.63}Ni{sub 0.24}Co{sub 0.13}O{sub 2} are confirmed by X-ray diffraction (XRD) and inductively coupled plasma atomic emission spectroscopy (ICP-AES). The first and second discharge capacities of 0.34Li{sub 2}MnO{sub 3}·0.66LiMn{sub 0.63}Ni{sub 0.24}Co{sub 0.13}O{sub 2} are measured to be 311 and 307 mA h g{sup −1}, respectively. The material also has an excellent rate capability (250 and 180 mA h g{sup −1} at 1 C and 5 C, respectively). In the rate capability test at 60 °C, 0.34Li{sub 2}MnO{sub 3}·0.66LiMn{sub 0.63}Ni{sub 0.24}Co{sub 0.13}O{sub 2} has a higher capacity of over 210 mA h g{sup −1} in the range 0.1–10 C. In the cyclic performance test, the capacity retention at high temperature is over 85% after 50 cycles, which is similar to that at room temperature. The 0.34Li{sub 2}MnO{sub 3}·0.66LiMn{sub 0.63}Ni{sub 0.24}Co{sub 0.13}O{sub 2} is therefore a high-capacity material with potential for use as an electrode in Li-ion batteries.
Mechanisms of impurity diffusion in rutile
Peterson, N.L.; Sasaki, J.
Tracer diffusion of /sup 46/Sc, /sup 51/Cr, /sup 54/Mn, /sup 59/Fe, /sup 60/Co, /sup 63/Ni, and /sup 95/Zr, was measured as functions of crystal orientation, temperature, and oxygen partial pressure in rutile single crystals using the radioactive tracer sectioning technique. Compared to cation self-diffusion, divalent impurities (e.g., Co and Ni) diffuse extremely rapidly in TiO/sub 2/ and exhibit a large anisotropy in the diffusion behavior; divalent-impurity diffusion parallel to the c-axis is much larger than it is perpendicular to the c-axis. The diffusion of trivalent impurity ions (Sc and Cr) and tetravalent impurity ions (Zr) is similar to cation self-diffusion, as a function of temperature and of oxygen partial pressure. The divalent impurity ions Co and Ni apparently diffuse as interstitial ions along open channels parallel to the c-axis. The results suggest that Sc, Cr, and Zr ions diffuse by an interstitialcy mechanism involving the simultaneous and cooperative migration of tetravalent interstitial titanium ions and the tracer-impurity ions. Iron ions diffused both as divalent and as trivalent ions. 8 figures.
Effects of dietary manganese and iron on manganese and iron metabolism during infancy
Kiehl, H.; Loennerdal, B. )
To derive a better understanding of the metabolism of Mn during infancy, infant formulas with different levels of Mn and Fe were labeled with {sup 54}Mn and {sup 59}Fe and administered orally to suckling rats: control low-Fe formula; control with 100-times Mn; and control with 100-times Fe. Another group received 200 {mu}g MnCl{sub 2} daily during infancy. 12 hr post-dosing, the pattern of {sup 54}Mn distribution in the tissues paralleled that of {sup 59}Fe. An excess of either mineral decreased overall retention but led to higher recoveries of both elements in the proximal intestine and liver. Conversely, these recoveries in pups given Mn from birth were lower than in controls. Analysis of the cytosolic fractions from intestine and liver using FPLC gel filtration demonstrated the impact of the mineral loads on protein profiles. In all cases except the high-Mn dose, dietary manipulations resulted in greater relative levels of a high molecular weight protein with MW similar to ferritin. The high-Mn formula seemed to induce in the hepatocyte a lower MW protein with which most of the {sup 54}Mn and {sup 59}Fe was associated. These results suggest a possible role of Mn as a regulator in the synthesis of cytosolic proteins of the enterocyte and hepatocyte in infants.
The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...
Technical basis for internal dosimetry at Hanford
Sula, M.J.; Carbaugh, E.H.; Bihl, D.E.
The Hanford Internal Dosimetry Program, administered by Pacific Northwest Laboratory for the US Department of Energy, provides routine bioassay monitoring for employees who are potentially exposed to radionuclides in the workplace. This report presents the technical basis for routine bioassay monitoring and the assessment of internal dose at Hanford. The radionuclides of concern include tritium, corrosion products ({sup 58}Co, {sup 60}Co, {sup 54}Mn, and {sup 59}Fe), strontium, cesium, iodine, europium, uranium, plutonium, and americium,. Sections on each of these radionuclides discuss the sources and characteristics; dosimetry; bioassay measurements and monitoring; dose measurement, assessment, and mitigation and bioassay follow-up treatment. 78 refs., 35 figs., 115 tabs.
Nuclear Decay Data for the International Reactor Dosimetry Library for Fission and Fusion (IRDFF): Updated Evaluations of the Half-Lives and Gamma Ray Intensities
NASA Astrophysics Data System (ADS)
Chechev, Valery P.; Kuzmenko, Nikolay K.
Updated evaluations of the half-lives and prominent gamma ray intensities have been presented for 20 radionuclides - dosimetry reaction residuals. The new values of these decay characteristics recommended for the IRDFF library were obtained using the approaches and methodology adopted by the working group of the Decay Data Evaluation Project (DDEP) cooperation. The experimental data published up to 2014 were taken into account in updated evaluations. The list of radionuclides includes 3H, 18F, 22Na, 24Na, 46Sc, 51Cr, 54Mn, 59Fe, 57Co, 60Co, 57Ni, 64Cu, 88Y, 132Te, 131I, 140Ba, 140La, 141Ce, 182Ta, 198Au.
Technical basis for internal dosimetry at Hanford
Sula, M.J.; Carbaugh, E.H.; Bihl, D.E.
The Hanford Internal Dosimetry Program, administered by Pacific Northwest Laboratory for the US Department of Energy, provides routine bioassay monitoring for employees who are potentially exposed to radionuclides in the workplace. This report presents the technical basis for routine bioassay monitoring and the assessment of internal dose at Hanford. The radionuclides of concern include tritium, corrosion products (/sup 58/Co, /sup 60/Co, /sup 54/Mn, and /sup 59/Fe), strontium, cesium, iodine, europium, uranium, plutonium, and americium. Sections on each of these radionuclides discuss the sources and characteristics; dosimetry; bioassay measurements and monitoring; dose measurement, assessment, and mitigation; and bioassay follow-up treatment. 64 refs., 42 figs., 118 tabs.
Uptake of radiolabeled ions in normal and ischemia-damaged brain.
Dienel, G A; Pulsinelli, W A
The regional concentrations of nine radiochemicals were measured in rat brain after induction of cerebral ischemia to identify tracers concentrated by brain undergoing selective neuronal necrosis. Transient (30 minute) forebrain ischemia was produced in the rat; 24 hours after cerebral recirculation the radiochemicals were injected intravenously and allowed to circulate for 5 hours. The brain concentrations of the radiochemicals in dissected regions were determined by scintillation counting. Forebrain ischemia of this nature will produce extensive injury to striatal neurons but will spare the great majority of neocortical neurons at 24 hours. The regional concentrations of these radiochemicals varied considerably in both control and ischemic animals. In postischemic animals, 4 radionuclides (63Ni, 99TcO4, 22Na, and [3H]tetracycline) were concentrated in the irreversibly damaged striatum in amounts ranging from 1.4 to 2.4 times greater than in normal tissue. The concentrations of 65Zn, 59Fe, 32PO4, and 147Pm in postischemic brain were similar to or less than those in normal brain. The concentration of [14C]EDTA was increased in injured and uninjured brain of postischemic rats. Autoradiographic analysis of the distribution patterns of some of these ions in normal animals showed that 99TcO4, 22Na, 65Zn, and 59Fe were distributed more uniformly throughout the brain than were 32PO4, 63Ni, and 147Pm. At 24 or 48 hours after ischemia, 63Ni, 99TcO4, and 22Na were preferentially concentrated in the damaged striatum and hippocampus, whereas 65Zn, 59Fe, 32PO4, and 147Pm did not accumulate in irreversibly injured tissue. Of the radiochemicals tested to date, Ni, TcO4, and tetracycline may be useful for diagnosing ischemic brain injury in humans, using positron emission tomography. PMID:3013076
Chemical and physical differentiation of superoxide dismutases in anaerobes.
Gregory, E M; Dapper, C H
Superoxide dismutase activity in crude or partially purified cell extracts from several species and strains of obligate anaerobe Bacteroides was inhibited instantaneously by NaN3 and was inactivated rapidly upon incubation with H2O2. The extent of NaN3 inhibition varied from 41 to 93%, and the half-life of the enzymatic activity in 5 mM H2O2 ranged from 1.2 to 6.1 min, depending upon the organism tests. When grown in a defined medium containing 59Fe, Bacteroides fragilis (VPI 2393) incorporated radiolabel into a 40,000-molecular-weight NaN3- and H2O2-sensitive superoxide dismutase but did not incorporate 54Mn into that protein under similar growth conditions. The anaerobe Actinomyces naeslundii (VPI 9985) incorporated 54Mn but not 59Fe into a NaN3-insensitive and H2O2-resistant superoxide dismutase. The apparent molecular weight of the superoxide dismutase from this and several other Actinomyces spp. was estimated to be 110,000 to 140,000. Comparison of these data with studies of homogeneous metallosuperoxide dismutases suggests that the Bacteroides spp. studied contain a ferrisuperoxide dismutase, whereas Actinomyces spp. contain a managanisuperoxide dismutase. PMID:7440509
Radioactivity of neutron-irradiated cat's-eye chrysoberyls
NASA Astrophysics Data System (ADS)
Tang, S. M.; Tay, T. S.
The recent report of marketing of radioactive chrysoberyl cat's-eyes in South-East Asian markets has led us to use an indirect method to estimate the threat to health these color-enhanced gemstones may pose if worn close to skin. We determined the impurity content of several cat's-eye chrysoberyls from Indian States of Orissa and Kerala using PIXE, and calculated the radioactivity that would be generated from these impurities and the constitutional elements if a chrysoberyl was irradiated by neutrons in a nuclear reactor for color enhancement. Of all the radioactive nuclides that could be created by neutron irradiation, only four ( 46Sc, 51Cr, 54Mn and 59Fe) would not have cooled down within a month after irradiation to the internationally accepted level of specific residual radioactivity of 2 nCi/g. The radioactivity of 46Sc, 51Cr and 59Fe would only fall to this safe limit after 15 months and that of 54Mn could remain above this limit for several years.
The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...
Review of Russian-language studies on radionuclide behaviour in agricultural animals: part 4. Transfer to poultry.
Fesenko, S; Howard, B J; Isamov, N; Beresford, N A; Barnett, C L; Sanzharova, N; Voigt, G
Data on radionuclide transfer to domestic chickens and ducks obtained from research performed in the former Soviet Union were reviewed to provide transfer coefficient values (Ff) to poultry and edible egg contents. The majority of the data are from experiments with (90)Sr and (137)Cs, reflecting the importance of these radionuclides after global fallout and major radiation accidents. Data for (3)H, (54)Mn, (59)Fe, (60)Co, (22)Na (65)Zn, (131)I and U are also given. The values derived have been compared with those in the current IAEA Handbook of parameter values for the prediction of radionuclide transfer in temperate environments (TRS 364) and the recent revision which incorporates the values from this paper. The Russian-language data give improved estimates for many radionuclides and the revised handbook is now based on the better quality data given for chronic administration. PMID:19632750
Level density and mechanism of deuteron-induced reactions on
Ramirez, A. P. D.; Voinov, A. V.; Grimes, S. M.; Byun, Y.; Brune, C. R.; Massey, T. N.; Akhtar, S.; Dhakal, S.; Parker, C. E.
Here, deuteron elastic cross sections, as well as neutron, proton, and α-particle emission spectra, from d+54,56,58Fe reactions have been measured with deuteron beam energies of 5, 7, and 9 MeV. Optical model parameters have been tested against our experimental data. The fraction of total reaction cross section responsible for the formation of compound nuclei has been deduced from the angular distributions. The degree of discrepancy between calculated and experimental compound cross sections was found to increase with increasing neutron number. The nuclear level densities of the residual nuclei 55Co, 57Co, 55Fe, 57Fe, 52Mn, and 54Mn have been deduced from the compound double differential cross sections. The Gilbert-Cameron model with Iljinov parameter systematics [A. S. Iljinov and M. V. Mebel, Nucl. Phys. A 543, 517 (1992)] was found to have a good agreement with our results.
Compilation and evaluation of 14-MeV neutron-activation cross sections for nuclear technology applications. Set I
Evain, B.P.; Smith, D.L.; Lucchese, P.
Available 14-MeV experimental neutron activation cross sections are compiled and evaluated for the following reactions of interest for nuclear-energy technology applications: /sup 27/Al(n,p)/sup 27/Mg, Si(n,X)/sup 28/Al, Ti(n,X)/sup 46/Sc, Ti(n,X)/sup 47/Sc, Ti(n,X)/sup 48/Sc, /sup 51/V(n,p)/sup 51/Ti, /sup 51/V(n,..cap alpha..)/sup 48/Sc, Cr(n,X)/sup 52/V, /sup 55/Mn(n,..cap alpha..)/sup 52/V, /sup 55/Mn(n,2n)/sup 54/Mn, Fe(n,X)/sup 54/Mn, /sup 54/Fe(n,..cap alpha..)/sup 51/Cr, /sup 59/Co(n,p)/sup 59/Fe, /sup 59/Co(n,..cap alpha..)/sup 56/Mn, /sup 59/Co(n,2n)/sup 58/Co, /sup 65/Cu(n,p)/sup 65/Ni, Zn(n,X)/sup 64/Cu, /sup 64/Zn(n,2n)/sup 63/Zn, /sup 113/In(n,n')/sup 113m/In, /sup 115/In(n,n') /sup 115m/In. The compiled values are listed and plotted for reference without adjustments. From these collected results those values for which adequate supplementary information on nuclear constants, standards and experimental errors is provided are selected for use in reaction-by-reaction evaluations. These data are adjusted as needed to account for recent revisions in the nuclear constants and cross section standards. The adjusted results are subsequently transformed to equivalent cross sections at 14.7 MeV for the evaluation process. The evaluations are performed utilizing a least-squares method which considers correlations between the experimental data. 440 refs., 41 figs., 46 tabs.
Heavy metal binding to heparin disaccharides. I. Iduronic acid is the main binding site.
Whitfield, D M; Choay, J; Sarkar, B
As model compounds for Ni(II)-binding heparin-like compounds isolated from human kidneys (Templeton, D.M. & Sarkar, B. (1985) Biochem. J. 230 35-42.), we investigated two disaccharides--4-O-(2-O-sulfo-alpha-L-idopyranosyluronic acid)-2,5-anhydro- D-mannitol, disodium salt (1a), and 4-O-(2-O-sulfo-alpha-L-idopyranosyluronic acid)-6-O- sulfo-2,5-anhydro-D-mannitol, trisodium salt (1b)--that were isolated from heparin after nitrous acid hydrolysis and reduction. The monosulfate (1a) was active whereas the disulfate (1b) was inactive in a high-performance liquid chromatography (HPLC) binding assay with the tracer ions 63Ni(II) 54Mn(II), 65Zn(II), and 109Cd(II). This result is in accord with the isolation of two 67Cu(II) and 63Ni(II) binding fractions from a complete pool of nitrous-acid-derived heparin disaccharides using sulfate gradients and a MonoQ anion exchange column on an FPLC system. One was identified as compound (1a) and the other as a tetrasulfated trisaccharide by high resolution FAB-MS, NMR and HPLC-PAD. Similarly, two synthetic disaccharides-methyl, 2-O-sulfo-4-O-(alpha-L-idopyranosyluronic acid)-2-deoxy-2-sulfamide-alpha-D-glucosamine, trisodium salt [IdopA2S(alpha 1,4)GlcNS alpha Me, 2a], and 2-O-sulfo-4-O-(alpha-L-idopyranosyluronic acid)-2-deoxy-2-sulfamide-6-O-sulfo- alpha-D-glucosamine, tetrasodium salt [IdopA2S (alpha 1,4)GlcNS6S alpha Me, 2b]--were shown to bind tracer amounts of 63Ni and 67Cu using chromatographic assays. Subsequently, 1H NMR titrations of 1a, 1b, 2a, and 2b with Zn (OAc)2 were analyzed to yield 1:1 Zn(II)-binding constants of 472 +/- 59, 698 +/- 120, 8,758 +/- 2,237 and 20,100 +/- 5,598 M-1, respectively. The values for 2a and 2b suggest chelation. It is suggested that the idopyranosiduronic acid residue is the major metal binding site. NMR evidence for this hypothesis comes from marked 1H and 13C chemical shift changes to the iduronic acid resonances after addition of diamagnetic Zn(II) ions. PMID:1643264
Calculation of extrapolation curves in the 4π(LS)β-γ coincidence technique with the Monte Carlo code Geant4.
Bobin, C; Thiam, C; Bouchard, J
At LNE-LNHB, a liquid scintillation (LS) detection setup designed for Triple to Double Coincidence Ratio (TDCR) measurements is also used in the β-channel of a 4π(LS)β-γ coincidence system. This LS counter based on 3 photomultipliers was first modeled using the Monte Carlo code Geant4 to enable the simulation of optical photons produced by scintillation and Cerenkov effects. This stochastic modeling was especially designed for the calculation of double and triple coincidences between photomultipliers in TDCR measurements. In the present paper, this TDCR-Geant4 model is extended to 4π(LS)β-γ coincidence counting to enable the simulation of the efficiency-extrapolation technique by the addition of a γ-channel. This simulation tool aims at the prediction of systematic biases in activity determination due to eventual non-linearity of efficiency-extrapolation curves. First results are described in the case of the standardization (59)Fe. The variation of the γ-efficiency in the β-channel due to the Cerenkov emission is investigated in the case of the activity measurements of (54)Mn. The problem of the non-linearity between β-efficiencies is featured in the case of the efficiency tracing technique for the activity measurements of (14)C using (60)Co as a tracer. PMID:26699674
Improved multi-element measurement of absorption via the fecal monitoring technique
Gibson, R.S.; Gibson, I.L.; Weber, C.E.; Atkinson, S.A.
The fecal monitoring technique for measuring the absorption of Mn, Se and Fe was studied in eight piglets using high resolution gamma spectrometry. Four day old piglets were fed a complete liquid diet for five days prior to the administration of an isotope dose (/sup 75/Se, /sup 54/Mn, /sup 59/Fe) equilibrated with the milk feeding. /sup 51/CrCl/sub 3/ was used as a fecal marker. Subsequently stool and urine samples were collected daily for 15-21 days. Following counting, the % fecal excretion of the administered dose was calculated. As 0 to 33% of the administered /sup 51/CrCl/sub 3/ was absorbed this fecal marker is inappropriate for piglets. Results indicate that endogenous excretion for each of the isotopes was not constant but decreased exponentially with time. An improved method for calculating the endogenous excretion was therefore developed. This method is based on the pattern of endogenous excretion in comparable piglets injected intravenously with the same isotopes, and on the level of endogenous excretion in the orally fed animals in the post-absorptive phase of excretion. These findings have important implications for the estimation of endogenous excretion in future fecal monitoring absorption studies. Previous results using the latter technique have frequently underestimated true absorption.
Diffusion of 3D-transition elements in Ti-54at%Al
Lee, C.G.; Iijima, Y.; Kim, S.E.; Lee, Y.T.; Kim, H.M.
The diffusion coefficients of iron, cobalt, manganese and chromium in Ti-54at%Al alloy were measured over the temperature range from 1,000 to 1,540 K. This study used the radioactive tracers {sup 59}Fe, {sup 57}Co, {sup 54}Mn and {sup 51}Cr and employed the serial the radio-frequency sputter-microsectioning method to measure the penetration profiles of the radioisotope into the specimen. The temperature dependence of the diffusion coefficients was analyzed to be expressed by the following Arrhenius equations: D{sub Fe/TiAl} = (1.3 {times} 10{sup {minus}3}) exp ({minus}363 kJ mol{sup {minus}1}/RT) m{sup 2}/s, D{sub Co/TiAl} = (1.1 {times} 10{sup {minus}3}) exp ({minus}318 kJ mol{sup {minus}1}/RT) m{sup 2}/s, D{sub Mn/TiAl} = (1.2 {times} 10{sup {minus}3}) exp ({minus}326 kJ mol{sup {minus}1}/RT) m{sup 2}/s, D{sub Cr/TiAl} = (4.4 {times} 10{sup {minus}3}) exp ({minus}350 kJ mol{sup {minus}1}/RT) m{sup 2}/s.
Activation Measurements for Thermal Neutrons, U.S. Measurements of 36Cl in Mineral Samples from Hiroshima and Nagasaki; and Measurement of 63 Ni in Copper Samples From Hiroshima by Accelerator Mass Spectrometry
Tore Straume; Alfredo A. Marchetti; Stephen D. Egbert; James A. Roberts; Ping Men; Shoichiro Fujita; Kiyoshi Shizuma; Masaharu Hoshi; G. Rugel; W. Ruhm; G. Korschinek; J. E. McAninch; K. L. Carroll; T. Faestermann; K. Knie; R. E. Martinelli; A. Wallner; C. Wallner
The present paper presents the {sup 36}Cl measurement effort in the US. A large number of {sup 36}Cl measurements have been made in both granite and concrete samples obtained from various locations and distances in Hiroshima and Nagasaki. These measurements employed accelerator mass spectrometry (AMS) to quantify the number of atoms of {sup 36}Cl per atom of total Cl in the sample. Results from these measurements are presented here and discussed in the context of the DS02 dosimetry reevaluation effort for Hiroshima and Nagasaki atomic-bomb survivors. The production of {sup 36}Cl by bomb neutrons in mineral samples from Hiroshima and Nagasaki was primarily via the reaction {sup 35}Cl(n,{gamma}){sup 36}Cl. This reaction has a substantial thermal neutron cross-section (43.6 b at 0.025 eV) and the product has a long half-life (301,000 y). hence, it is well suited for neutron-activation detection in Hiroshima and Nagasaki using AMS more than 50 years after the bombings. A less important reaction for bomb neutrons, {sup 39}K(n,{alpha}){sup 36}Cl, typically produces less than 10% of the {sup 36}Cl in mineral samples such as granite and concrete, which contain {approx} 2% potassium. In 1988, only a year after the publication of the DS86 final report (Roesch 1987), it was demonstrated experimentally that {sup 36}Cl measured using AMS should be able to detect the thermal neutron fluences at the large distances most relevant to the A-bomb survivor dosimetry. Subsequent measurements in mineral samples from both Hiroshima and Nagasaki validated the experimental findings. The potential utility of {sup 36}Cl as a thermal neutron detector in Hiroshima was first presented by Haberstock et al. who employed the Munich AMS facility to measure {sup 36}Cl/Cl ratios in a gravestone from near the hypocenter. That work subsequently resulted in an expanded {sup 36}Cl effort in Germany that paralleled the US work. More recently, there have also been {sup 36}Cl measurements made by a Japanese group. The impetus for the extensive {sup 36}Cl and other neutron activation measurements was the recognized need to validate the neutron component of the dose in Hiroshima. Although this was suggested at the time of the DS86 Final Report, where it was stated that the calculated neutron doses for survivors could possibly be wrong, the paucity of neutron validation measurements available at that time prevented adequate resolution of this matter. It was not until additional measurements and data evaluations were made that it became clear that more work was required to better understand the discrepancies observed for thermal neutrons in Hiroshima. This resulted in a large number of additional neutron activation measurements in Hiroshima and Nagasaki by scientists in the US, Japan, and Germany. The results presented here for {sup 36}Cl, together with measurements made by other scientists and for other isotopes, now provide a much improved measurement basis for the validation of neutrons in Hiroshima.
Radioactive effluents in Savannah River. Summary report for 1992
Winn, W.G.
During 1992, the radioactive effluents in the Savannah River were less than those observed in 1991. Vogtle reported no significant releases in 1992, and in earlier years Vogtle improvements in pre-processing their releases had already effected a decreasing trend in release levels. Their effluents continue to be dominated by {sup 58}Co, which had a maximum concentration of only 0.068 pCi/L, which is just 1/3 of the maximum observed in 1991. Many of the other man-made radionuclides observed in earlier years have now decreased to where some are not even detected, and no new radionuclides were detected in the 1992 Vogtle effluents. In addition to {sup 58}Co, low levels of {sup 60}Co were frequently observed, but only traces of {sup 54}Mn and {sup 95}Nb were observed. Contrary to earlier years no {sup 51}Cr, {sup 57}Co, {sup 59}Fe, or {sup 95}Zr were seen in 1992. Tritium and {sup 137}Cs were also monitored, but their levels generally remain consistent with known SRS sources. The maximum tritium observed near Vogtle was 2 pCi,/mL. The maximum downstream tritium was higher (3.8 pCi/mL), primarily due to the tritium release from K-Reactor in December 1991; however, the levels had abated significantly prior to collection of the tritium samples of the present study. In addition to natural sources, the general levels in the Savannah River are due to routine releases from the effluent treatment facility and seepage basin migration into plant streams that flow into the river.
Interactions between radioactively labeled colloids and natural particles: Evidence for colloidal pumping
Wen, L.S.; Santschi, P.H.; Tang, D.
It has been hypothesized that colloidal forms of trace metals can be reactive intermediaries in the scavenging processes leading to the removal of their particulate forms. A series of radiotracer experiments using natural colloidal organic matter from Galveston Bay, USA were carried out in order to test this hypothesis. Suspended particle uptake of originally colloidally bound trace metals occurred in a matter of hours to days in estuarine waters. After ten days, the majority ( >50%) of the colloidal trace metals had been transferred into the particulate phase ({ge} 0.45{mu}m), except for {sup 65}Zn. Two distinctively different temporal regions of removal of colloidal trace metals were identified: a faster reaction during the first four hours, followed by a slower reaction after approximately one day. In a separate river water-seawater mixing experiment, the solid/solution partitioning of the radiotracers was investigated in the absence of suspended matter. About 30% of most of the elements, except Ag and Fe ({approximately}60%), were associated with a newly formed particulate phase after eight days. There were two major trends: (1) the particulate fraction of {sup 59}Fe and {sup 110}Ag increased while the colloidal fraction decreased, suggesting a colloidal pumping mechanism. (2) The particulate fraction of {sup 54}Mn, {sup 133}Ba, {sup 65}Zn, {sup 109}Cd, {sup 113}Sn, and {sup 60}Co increased while the LMW({le}1 kDa) fraction decreased, suggesting a direct uptake into the particulate fraction with less involvement of a transitory colloidal phase. The results from these experiments suggested two different pathways for colloidal tracer uptake by particles: (1) colloidal pumping of a major component (e.g., biopolymer) of the colloidal pool and (2) coagulation of trace components (e.g., phytochelatins) with varying affinities for different trace metals. 39 refs., 8 figs., 3 tabs.
Ferroportin deficiency impairs manganese metabolism in flatiron mice
Seo, Young Ah; Wessling-Resnick, Marianne
We examined the physiologic role of ferroportin (Fpn) in manganese (Mn) export using flatiron (ffe/+) mice, a genetic model of Fpn deficiency. Blood (0.0123 vs. 0.0107 mg/kg; P = 0.0003), hepatic (1.06 vs. 0.96 mg/kg; P = 0.0125), and bile Mn levels (79 vs. 38 mg/kg; P = 0.0204) were reduced in ffe/+ mice compared to +/+ controls. Erythrocyte Mn–superoxide dismutase was also reduced at 6 (0.154 vs. 0.096, P = 0.0101), 9 (0.131 vs. 0.089, P = 0.0162), and 16 weeks of age (0.170 vs. 0.090 units/mg protein/min; P < 0.0001). 54Mn uptake after intragastric gavage was markedly reduced in ffe/+ mice (0.0187 vs. 0.0066% dose; P = 0.0243), while clearance of injected isotope was similar in ffe/+ and +/+ mice. These values were compared to intestinal absorption of 59Fe, which was significantly reduced in ffe/+ mice (8.751 vs. 3.978% dose; P = 0.0458). The influence of the ffe mutation was examined in dopaminergic SH-SY5Y cells and human embryonic HEK293T cells. While expression of wild-type Fpn reversed Mn-induced cytotoxicity, ffe mutant H32R failed to confer protection. These combined results demonstrate that Fpn plays a central role in Mn transport and that flatiron mice provide an excellent genetic model to explore the role of this exporter in Mn homeostasis.—Seo, Y. A., Wessling-Resnick, M. Ferroportin deficiency impairs manganese metabolism in flatiron mice. PMID:25782988
Accumulation of radioactive corrosion products on steel surfaces of VVER-type nuclear reactors. II. 60Co
NASA Astrophysics Data System (ADS)
Varga, Kálmán; Hirschberg, Gábor; Németh, Zoltán; Myburg, Gerrit; Schunk, János; Tilky, Péter
In the case of intact fuel claddings, the predominant source of radioactivity in the primary circuits of water-cooled nuclear reactors is the activation of corrosion products in the core. The most important corrosion product radionuclides in the primary coolant of pressurized water reactors (PWRs) are 60Co, 58Co, 51Cr, 54Mn, 59Fe (as well as 110mAg in some Soviet-made VVER-type reactor). The second part of this series is focused on the complex studies of the formation and build-up of 60Co-containing species on an austenitic stainless steel type 08X18H10T (GOST 5632-61) and magnetite-covered carbon steel often to be used in Soviet-planned VVERs. The kinetics and mechanism of the cobalt accumulation were studied by a combination (coupling) of an in situ radiotracer method and voltammetry in a model solution of the primary circuit coolant. In addition, independent techniques such as X-ray photoelectron spectroscopic (XPS) and ICP-OES are also used to analyze the chemical state of Co species in the passive layer formed on stainless steel as well as the chemical composition of model solution. The experimental results have revealed that: (i) The passive behavior of the austenitic stainless steel at open-circuit conditions, the slightly alkaline pH and the reducing water chemistry can be considered to be optimal to minimize the 60Co contamination. (ii) The highly potential dependent deposition of various Co-oxides at E>1.10 V (vs. RHE) offers a unique possibility to elaborate a novel electrochemical method for the decrease or removal of cobalt traces from borate-containing coolants contaminated with 60Co and/or 58Co radionuclides.
Investigation of Some Stellar Iron Group Fusion Materials for ( n, p) Reactions
NASA Astrophysics Data System (ADS)
Sahan, M.; Tel, E.; Aydin, A.; Yegingil, Ilhami
In this study, we present the results of a careful analysis of cross sections of some important iron (Fe) group target elements (20 ≤ Z≤28) for astrophysical ( n, p) reactions such as Si, Ca, Sc, Ti, V, Cr, Fe, Co and Ni used in neutron activation analysis have been investigated. The new calculations on the excitation functions of 28 Si(n, p) 28 Al, 29 Si(n, p) 29 Al, 42 Ca(n, p) 42 K, 45 Sc(n, p) 45 Ca, 46 Ti(n, p) 46 Sc, 51 V(n, p) 51 Ti, 52 Cr(n, p) 52 V, 53 Cr(n, p) 53 V, 54 Fe(n, p) 54 Mn, 57 Fe(n, p) 57 Mn, 59 Co(n, p) 59 Fe, 58 Ni(n, p) 58 Co and 60 Ni(n, p) 60 Co reactions have been carried out up to 25 MeV incident neutron energy. In these calculations, the pre-equilibrium and equilibrium effects have been investigated. Equilibrium effects are calculated according to the Weisskopf-Ewing model. The pre-equilibrium calculations involve the geometry dependent hybrid model, hybrid model and equilibrium model. Also in the present work, these reaction cross-sections have been calculated by using evaluated empirical formulas developed by Tel et al. at 14.7 MeV energy. The calculations are compared with existing experimental data as well as with evaluated data files (Experimental Nuclear Reaction Data (EXFOR). According to these calculations, we assume that these model calculations can be applied to some heavy elements, ejected into interstellar medium by dramatic supernova events.
National Low-Level Waste Management Program Radionuclide Report Series. Volume 10, Nickel-63
Carboneau, M.L.; Adams, J.P.
This report outlines the basic radiological, chemical, and physical characteristics of nickel-63 ({sup 63}Ni) and examines how these characteristics affect the behavior of {sup 63}Ni in various environmental media, such as soils, groundwater, plants, animals, the atmosphere, and the human body. Discussions also include methods of {sup 63}Ni production, waste types, and waste forms that contain {sup 63}Ni. The primary source of {sup 63}Ni in the environment has been low-level radioactive waste material generated as a result of neutron activation of stable {sup 62}Ni that is present in the structural components of nuclear reactor vessels. {sup 63}Ni enters the environment from the dismantling activities associated with nuclear reactor decommissioning. However, small amounts of {sup 63}Ni have been detected in the environment following the testing of thermonuclear weapons in the South Pacific. Concentrations as high as 2.7 Bq{sup a} per gram of sample (or equivalently 0.0022 parts per billion) were observed on Bikini Atoll (May 1954). {sup 63}Ni was not created as a fission product species (e.g., from {sup 235}U or {sup 239}Pu fissions), but instead was produced as a result of neutron capture in {sup 63}Ni, a common nickel isotope present in the stainless steel components of nuclear weapons (e.g., stainless-304 contains {approximately}9% total Ni or {approximately}0.3% {sup 63}Ni).
A Method to Estimate the Fast-Neutron Fluence for the Hiroshima Atomic Bomb
NASA Astrophysics Data System (ADS)
Shibata, Tokushi; Imamura, Mineo; Shibata, Seiichi; Uwamino, Yoshitomo; Ohkubo, Tohru; Satoh, Shinngo; Nogawa, Norio; Hasai, Hiromi; Shizuma, Kiyoshi; Iwatani, Kazuo; Hoshi, Masaharu; Oka, Takamitsu
A new method to estimate the fast-neutron fluence of the Hiroshima atomic bomb is proposed. 63Ni produced by the 63Cu(n, p)63Ni reaction provides a unique measure by which to estimate the fast-neutron fluence of the Hiroshima/Nagasaki atomic bombs, because the half-life of 63Ni is 100 years and 70% of the 63Ni produced in a copper piece presently exists after 50 years. Using the neutron spectrum given in DS86 and the estimated cross section, we found that a piece of copper of about 10 g which was exposed at a point around 100 m from the hypocenter gives a measurable amount of 63Ni using a low-background liquid scintillation counter. For the measurement of 63Ni, accelerator mass spectrometry also seems to be applicable.
Interactions between radioactively labeled colloids and natural particles: Evidence for colloidal pumping
NASA Astrophysics Data System (ADS)
Wen, Liang-Saw; Santschi, Peter H.; Tang, Degui
It has been hypothesized that colloidal forms of trace metals can be reactive intermediaries in the scavenging processes leading to the removal of their particulate forms. A series of radiotracer experiments using natural colloidal organic matter from Galveston Bay, USA were carried out in order to test this hypothesis. Suspended particle uptake of originally colloidally bound trace metals occurred in a matter of hours to days in estuarine waters. After ten days, the majority (>50%) of the colloidal trace metals had been transferred into the particulate phase (≥0.45 μm), except for 65Zn. Two distinctively different temporal regions of removal of colloidal trace metals were identified: a faster reaction during the first four hours, followed by a slower reaction after approximately one day. In a separate river water-seawater mixing experiment, the solid/solution partitioning of the radiotracers was investigated in the absence of suspended matter. About 30% of most of the elements, except Ag and Fe (˜60%), were associated with a newly formed particulate phase after eight days. There were two major trends: (1) the particulate fraction of 59Fe and 110Ag increased while the colloidal fraction decreased, suggesting a colloidal pumping mechanism. (2) The particulate fraction of 54Mn, 133Ba, 65Zn, 109Cd, 113Sn, and 60CO increased while the LMW (≤ 1 kDa) fraction decreased, suggesting a direct uptake into the particulate fraction with less involvement of a transitory colloidal phase. The values of the particle-water ( Kd) and colloid-water partitioning ( Kc) coefficients for most trace metals were similar to those observed in Galveston Bay waters, suggesting complementary results to field studies. The results from these experiments suggested two different pathways for colloidal tracer uptake by particles: (1) colloidal pumping of a major component (e.g., biopolymer) of the colloidal pool and (2) coagulation of trace components (e.g., phytochelatins) with varying
Health Risk Assessment of Irradiated Topaz
NASA Astrophysics Data System (ADS)
Nelson, Kevin Lyle
Radiation-produced blue topaz, indistinguishable from natural blue topaz, is produced by several different techniques. Published information on radionuclides present, activity levels, equipment necessary to detect activated nuclides and dosimetric assessment is lacking. Using a 60 megawatt nuclear reactor, fifty-one samples of colorless topaz from Nigeria, Sri Lanka, India and Brazil were irradiated with thermal and fast neutron fluences ranging from 1.8 times 10 13 to 9.2 times 1018 neutrons cm^{-2}. Seventeen MeV electrons produced by a linear accelerator were also used to irradiate 36 colorless topaz from the same countries. Gamma ray or positron-emitting nuclides were identified using calibrated well-type NaI or germanium detectors. For germanium detectors having relative efficiencies of approximately 20 percent, an analysis time of one hour or more was needed. Geiger Mueller (G-M) detectors, scintillators (plastic and liquid), gas flow proportional counters, a ZnS detector and autoradiography techniques were used to measure charged particle activity. Isotopes produced from neutron activation included 182Ta, ^ {59}Fe, 46Sc, 51Cr, 54Mn, 124Sb, ^{32 }P, 77As, ^ {183}Ta, 77Ge, 72Ga, and ^{24 }Na. Possible nuclides produced from 17 MeV electron treatment include ^{68 }Ga, 64Cu, ^ {49}Cr, and 18F. Positive identification of the electron activated nuclides was not possible because of the short half-lives involved (<1 day). Of the possible pure beta emitters activated during neutron bombardment, 32P and 35S are the most likely to be produced. The identification of 32P was made using a three point beta absorption analysis with a G-M detector. Skin and breast cancer risk estimates were calculated for various sized topaz containing NRC exempt concentration levels. When compared to a negligible individual risk level (NIRL) of 10^{-7}, the risk of an irradiated topaz in contact with the skin or three inches from breast tissue was a small fraction of the NIRL. At a risk
Dissociation of a ferric maltol complex and its subsequent metabolism during absorption across the small intestine of the rat.
Barrand, M. A.; Callingham, B. A.; Dobbin, P.; Hider, R. C.
1. The fate and disposition of [59Fe]-ferric [3H]-maltol after intravenous administration were investigated in anaesthetized rats. Immediate dissociation of ferric iron from maltol took place in the circulation even with high doses of ferric maltol (containing 1 mg elemental iron). In plasma samples withdrawn within 1 min of injection and subjected to gel filtration, 59Fe eluted with the high molecular weight proteins whilst the tritium was associated with low molecular weight material. 2. The rates of elimination of 59Fe and of tritium from the plasma and their ultimate fate were very different. The half life for 59Fe in the plasma was around 70 min and 59Fe appeared mainly in the bone marrow and liver. There was an initial rapid exit of tritium from the plasma with a half life of around 12 min. This was followed either by a plateau or by a rise in tritium levels, involving entry of maltol metabolites into the circulation. These metabolites could be recovered in the urine. 3. Entry of 59Fe and of tritium into the blood plasma after intraduodenal administration of [59Fe]-ferric [3H]-maltol was also very different. At low doses of ferric maltol (containing 100 micrograms elemental iron), the tritium appeared in the plasma in highest amounts within seconds and then decreased whilst there was a slow rise in 59Fe levels. At higher doses of ferric maltol (containing 7 mg elemental iron), levels of 59Fe in the plasma were highest at 5 min and then fell whereas tritium levels rose steadily. Mucosal processing of 59Fe prevented further entry of iron at high dose into the circulation.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:1364845
Corrections for Exchange and Screening Effects in Low-energy Beta Decays
Mougeot, X. Bé, M.-M.; Bisch, C.; Loidl, M.
The beta spectra of {sup 241}Pu and {sup 63}Ni have been recently measured using metallic magnetic calorimeters. This powerful experimental technique allows theoretical beta spectra calculations to be tested at low energy with an accuracy never before achievable. Their comparison with classical beta calculations exhibits a significant deviation below 4 keV for {sup 241}Pu and 8 keV for {sup 63}Ni. The atomic exchange effect explains the main part of this deviation in the {sup 63}Ni beta spectrum. This effect has a significant contribution, equivalent to the magnitude of the screening, in the {sup 241}Pu beta spectrum.
Nickel-63 production in copper samples exposed to the Hiroshima atomic bomb: estimation based on an excitation function obtained by neutron irradiation experiments.
Takamiya, K; Imanaka, T; Ota, Y; Akamine, M; Shibata, S; Shibata, T; Ito, Y; Imamura, M; Uwamino, Y; Nogawa, N; Baba, M; Iwasaki, S; Matsuyama, S
The upper and lower limits of the excitation function of the (63)Cu(n,p)(63)Ni reaction were experimentally determined, and the number of (63)Ni nuclei produced in copper samples exposed to atomic bomb neutrons in Hiroshima was estimated by using the experimental excitation functions and the neutron fluences given in the DS02 dosimetry system. The estimated number of (63)Ni nuclei was compared with that measured and with that calculated using the DS02 dosimetry system and the corresponding ENDF/B-VI cross section. In comparison with DS02, there is about a 60% maximum difference in (63)Ni production at the hypocenter when the experimental upper cross section values are used. The difference becomes smaller at greater distances from the hypocenter and decreases, for example, to less than 30 and 5% when using the upper and lower experimental cross sections at 1,000 m, respectively. PMID:18496703
Comparison of reactant and analyte ions for ⁶³Nickel, corona discharge, and secondary electrospray ionization sources with ion mobility-mass spectrometry.
Crawford, C L; Hill, H H
(63)Nickel radioactive ionization ((63)Ni) is the most common and widely used ion source for ion mobility spectrometry (IMS). Regulatory, financial, and operational concerns with this source have promoted recent development of non-radioactive sources, such as corona discharge ionization (CD), for stand-alone IMS systems. However, there has been no comparison of the negative ion species produced by all three sources in the literature. This study compares the negative reactant and analyte ions produced by three sources on an ion mobility-mass spectrometer: conventional (63)Ni, CD, and secondary electrospray ionization (SESI). Results showed that (63)Ni and SESI produced the same reactant ion species while CD produced only the nitrate monomer and dimer ions. The analyte ions produced by each ion source were the same except for the CD source which produced a different ion species for the explosive RDX than either the (63)Ni or SESI source. Accurate and reproducible reduced mobility (K0) values, including several values reported here for the first time, were found for each explosive with each ion source. Overall, the SESI source most closely reproduced the reactant ion species and analyte ion species profiles for (63)Ni. This source may serve as a non-radioactive, robust, and flexible alternative for (63)Ni. PMID:23598216
Toxicology and metabolism of nickel compounds. Progress report, 1 December 1984-30 November 1985
Sunderman, F.W. Jr.
Administration of NiCl/sub 2/ to rats was shown to cause lipid peroxidation. Acute hepatic injury induced by NiCl/sub 2/ in rats was found to be associated with microvesicular steatosis of hepatocytes, substantial increases of serum aspartate aminotransferase and alanine aminotransferase activities, and diminished activity of serum alkaline phosphatase. Biliary excretion was observed to be quantitatively unimportant for the elimination of nickel. Less than 0.5% of injected /sup 63/Ni was excreted in rat bile within 24 hr after administration of /sup 63/NiCl/sub 2/. During 24 hr after administration of /sup 63/NiCl/sub 2/ to rats, 2% of total renal /sup 63/Ni was present in nuclei that were isolated by sucrose gradient centrifugation. Combined administration of diethyldithiocarbamate (DDC) and /sup 63/NiCl/sub 2/ doubled the uptake of /sup 63/Ni into renal nuclei. Enhanced nuclear uptake of /sup 63/Ni evidently explains the synergistic effects of DDC and NiCl/sub 2/ on induction of renal heme oxygenase activity. Tissue culture of cells from a Ni/sub 3/S/sub 2/-induced renal adenocarcinoma resulted in an aggressive tumor cell line that secretes erythropoietin into the medium and induces invasive, metastasizing tumors in nude mice. An accurate, sensitive, and convenient method was developed for tissue nickel analysis by Zeeman atomic absorption spectrophotometry (ZEAAS). The direct ZEAAS procedure was used to measure nickel concentrations in human subjects, including healthy controls, patients with acute myocardial infarction and severe angina pectoris, patients with maintenance hemodialysis for end-stage renal disease, patients with disulfiram therapy of chronic alcoholism, and patients with stainless-steel hip prostheses. 22 refs., 3 tabs.
Effect of certain variables on the tumor and tissue distribution of tracers. Salicylates and vasoactive drugs
Halpern, S.E.; Hagan, P.; Stern, P.; Gordon, R.; Dabbs, J.
Attempts were made to increase the viable tumor concentration of 54Mn and 67Ga in a rat hepatoma model by administering rat angiotensin, tolazoline, and salicylates. Salicylates increased the tumor concentrations of 54Mn and improved 65Mn viable tumor/background ratios. 67Ga was not affected by the salicylates. The salicylate effect appeared to be mediated by intracellular mechanisms rather than alterations in plasma protein binding. Rat angiotensin slightly increased the concentrations of 67Ga in the tumors but not enough to suggest that it would be useful clinically. Tolazoline did not increase tumor uptake of the tracers.
The effect of soy products in the diet on retention of non-heme iron from radiolabeled test meals fed to marginally iron-deficient young rats
Thompson, D.B.
Diets based either on casein or soy products and containing about 25 ppm iron were fed to weanling rats for 13 days. Rats were fasted overnight and fed a {sup 59}Fe-radiolabeled casein test meal the morning of day 14. On day 21 less {sup 59}Fe was retained by rats fed various diets based on selected soy products than by rats fed the casein-based diet. A similar adverse effect of diet components on {sup 59}Fe retention from a casein test meal was observed for lactalbumin and for psyllium husk. No adverse effect of diet on {sup 59}Fe retention was observed for the fiber of soy cotyledons or for rapeseed protein concentrate. For a commercial soy protein isolated (SPI) fed throughout the 21-day experiment, the adverse effect of diet on {sup 59}Fe retention was observed to the sum of the effect of dietary SPI previous to the {sup 59}Fe-radiolabeled casein test meal fed on day 14 and the effect of dietary SPI subsequent to the casein test meal. An effect of dietary soy products on {sup 59}Fe retention from a casein test meal was not observed with diets containing higher iron levels (83 ppm) or when diets were fed for a longer period prior to the test meal (56 days). The present work shows that in some circumstances the concept of iron bioavailability must be expanded to include not only the influence of meal composition, but also the influence of diet previous to and subsequent to a meal.
Comparative phloem Mobility of nickel in nonsenescent plants. [Pisum sativa L. ; Pelargonium zonale L
Neumann, P.M.; Chamel, A.
/sup 63/Ni was applied to nonsenescent source leaves and found to be transported to sink tissues in pea (Pisum saativum L.) and geranium plants (Pelargonium zonale L.). The comparative mobilities (percent tracer transported out of source leaf division % /sup 86/Rb transported) for /sup 63/Ni in peas was 2.12 and in geranium 0.25. The value for the phloem mobile /sup 86/Rb was 1.00. By contrast, the comparative mobility of /sup 45/Ca, which is relatively immobile in the phloem, was low (0.05 in peas, 0.00 in geranium). Interruption of the phloem pathway between source and sink leaves by steam girdling almost completely inhibited /sup 63/Ni accumulation in the sink leaves of both species. The authors conclude that Ni is transported from nonsenescent source leaves to sink tissues via the phloem of leguminous and nonleguminous plants.
A radioisotope-powered surface acoustic wave transponder
NASA Astrophysics Data System (ADS)
Tin, S.; Lal, A.
We demonstrate a 63Ni radioisotope-powered pulse transponder that has a SAW (surface acoustic wave) device as the frequency transmission frequency selector. Because the frequency is determined by a SAW device, narrowband detection with an identical SAW device enables the possibility for a long-distance RF-link. The SAW transponders can be buried deep into structural constructs such as steel and concrete, where changing batteries or harvesting vibration or EM energy is not a reliable option. RF-released power to radioisotope- released power amplification is 108, even when regulatory safe amounts of 63Ni are used. Here we have achieved an 800 µW pulse (315 MHz, 10 µs pause) across a 50 Ω load every 3 min, using a 1.5 milli-Ci 63Ni source.
A common viral infection can change nickel target organ distribution
Ilbaeck, N.G.F.; Fohlman, J.; Friman, G. )
The autoradiographic distribution of the toxic heavy metal nickel (Ni) was studied at 4 and 7 days post-coxsackievirus B3 (CB3) infection in Balb/c mice. The distribution of the iv injected 63Ni was studied 10 min, 4 hr, and 24 hr after administration. Results clearly show that the site of 63Ni accumulation is greatly changed during this viral infection. This newly discovered distribution was mainly visible as a greatly increased accumulation in the pancreas and the wall of the ventricular myocardium. Healthy animals showed almost no 63Ni accumulation in these tissues. These results for the first time show that an invading microorganism can change the distribution of an environmental pollutant.
Molecular mechanisms of non-transferrin-bound and transferring-bound iron uptake in primary hippocampal neurons
Ji, Changyi; Kosman, Daniel J.
The molecular mechanisms of iron trafficking in neurons have not been elucidated. In this study, we characterized the expression and localization of ferrous iron transporters Zip8, Zip14 and DMT1, and ferrireductases Steap2 and SDR2 in primary rat hippocampal neurons. Steap2 and Zip8 partially co-localize, indicating these two proteins may function in Fe3+ reduction prior to Fe2+ permeation. Zip8, DMT1 and Steap2 co-localize with the transferrin receptor (TfR)/transferrin (Tf) complex, suggesting they may be involved in TfR/Tf-mediated iron assimilation. In brain interstitial fluid, transferring-bound iron (TBI) and non-transferrin-bound iron (NTBI) exist as potential iron sources. Primary hippocampal neurons exhibit significant iron uptake from TBI (Transferrin-59Fe3+) and NTBI, whether presented as 59Fe2+-citrate or 59Fe3+-citrate; reductase-independent 59Fe2+ uptake was the most efficient uptake pathway of the three. Kinetic analysis of Zn2+ inhibition of Fe2+ uptake indicated that DMT1 plays only a minor role in the uptake of NTBI. In contrast, localization and knockdown data indicate that Zip8 makes a major contribution. Data suggest also that cell accumulation of 59Fe from TBI relies at least in part on an endocytosis-independent pathway. These data suggest that Zip8 and Steap2 play a major role in iron accumulation from NTBI and TBI by hippocampal neurons. PMID:25649872
Iron-59 absorption from soy hulls: intrinsic vs extrinsic labeling
Lykken, G.I.; Mahalko, J.R.; Nielsen, E.J.; Dintzis, F.R.
As part of an evaluation of the validity of the extrinsic labeling technique for measuring iron absorption, absorption from soy hulls extrinsically labeled (/sup 59/Fe added to bread dough) was compared with that from soy hulls intrinsically labeled (/sup 59/Fe incorporated into the soy plant during growth). Century soybeans were grown in a greenhouse. After pods had formed and were filling, each plant was stem injected twice, at 3 day intervals, with 22 ..mu..Ci /sup 59/Fe as FeCl/sub 2/ in 25 ..mu..l of 0.5 M HCl solution. After the plants had senesced, the soybeans were harvested, dried, shelled and the hulls removed. Standard meals containing 3.5 mg Fe/meal and up to 0.06 ..mu..Ci /sup 59/Fe in a soy hull bun were fed on 2 consecutive days to free-living volunteers in a crossover design. Absorption of /sup 59/Fe was greater from intrinsically labeled soy hulls than from extrinsically labeled soy hulls, 20 +/- 20% vs 15 +/- 11% (n=14, p > 0.05 by paired t-test). Apparent absorption ranged from 1.3% to 77% from intrinsically labeled soy hulls and .5% to 29% from extrinsically labeled soy hulls with the highest absorption occurring in persons with low serum ferritin (S.F. < 8 ng/ml). These findings provide additional evidence that the extrinsic labeling method is a valid measure of iron bioavailability to humans.
A/sub 1/ and A/sub 2/ adenosine receptor regulation of erythropoietin production
Ueno, M.; Brookins, J.; Beckman, B.; Fisher, J.W.
The effects of adenosine (ADE) and ADE agonists on erythropoietin (Ep) production were determined using percent (%) /sup 59/Fe incorporation in red cells of exhypoxic polycythemic mice. The hemisulfate salt of ADE produced a significant increase in % /sup 59/Fe incorporation in response to hypoxia in concentrations of 400 to 1600 nmol/kg/day. 5'-N-ethyl-carboxamideadenosine (NECA), a selective A/sub 2/ receptor agonist, increased radioiron incorporation in a dose-dependent manner. In contrast, N/sup 6/-cyclohexyladenosine (CHA), a selective A/sub 1/ receptor agonist, did not affect radioiron incorporation in concentrations up to 1600 nmol/kg/day. Albuterol, a beta 2-adrenergic agonist, enhanced % /sup 59/Fe incorporation in polycythemic mice and low doses of CHA, which were not effective alone on % /sup 59/Fe incorporation in polycythemic mice exposed to hypoxia, inhibited the enhancement in radioiron induced by albuterol plus hypoxia. Theophylline, a well-known antagonist of ADE receptors, blocked the ADE and NECA enhancement in radioiron incorporation at a dose of theophylline alone which produced only a slight enhancement of % /sup 59/Fe incorporation.
Search for anomalies in the decay of radioactive Mn-54
NASA Astrophysics Data System (ADS)
Silverman, M. P.
Recent papers have reported that 54Mn, which decays by electron capture (a weak nuclear interaction) with half-life ∼312 days, is influenced by solar activity. Should this actually occur, new physics would be needed to explain it. This paper reports results of an analysis of 54Mn activity measured over a time interval of ∼3.6 half-lives. If standard nuclear physics applies, the logarithmic residuals of 54Mn activities should form a stationary set of independent random variables whose statistics are determined solely by a constant decay rate λ and initial mean count μ. Analysis of the time-variation, autocorrelation, and power spectra of the 54Mn logarithmic residuals agrees exquisitely with standard nuclear physics. Computer-simulated activities exhibiting periodic decay of amplitude A=αλ show that anomalies would be detectable by these statistical tests for values of α as low as ∼1 part in 104. This limit is about 10 times lower than reported deviations from exponential decay.
Corrosion-resistant fuel cladding allow for liquid metal fast breeder reactors
Brehm, Jr., William F.; Colburn, Richard P.
An aluminide coating for a fuel cladding tube for LMFBRs (liquid metal fast breeder reactors) such as those using liquid sodium as a heat transfer agent. The coating comprises a mixture of nickel-aluminum intermetallic phases and presents good corrosion resistance to liquid sodium at temperatures up to 700.degree. C. while additionally presenting a barrier to outward diffusion of .sup.54 Mn.
Uncertainties of DS86 and prospects for residual radioactivity measurement.
Shizuma, K; Hoshi, M; Hasai, H
Residual radioactivity data of 152Eu, 60Co and 36Cl have been accumulated and it has been revealed in the thermal neutron region that a systematic discrepancy exists between the measured data and activation calculation based on the DS86 neutrons in Hiroshima. Recently 63Ni produced in copper samples by the fast neutron reaction 63Cu(n,p)63Ni has been of interest for evaluation of fast neutrons. Reevaluation of atomic-bomb neutrons and prospects based on residual activity measurements have been discussed. PMID:10805002
Use of poisons in determination of microbial manganese binding rates in seawater
Rosson, R.A.; Tebo, B.M.; Nealson, K.H.
A method was developed to determine whether microorganisms mediate the precipitation of manganese(II) in the marine environment. Radioactive /sup 54/Mn(II) was used as a tracer to measure the precipitation (binding and oxidation) of Mn(II) (i.e., the /sup 54/Mn(II) trapped on 0.2-..mu..m membrane filters) in the presence and absence of biological poisons. A variety of antibiotics, fixatives, and metabolic inhibitors were tested in laboratory control experiments to select poisons that did not interfere in the chemistry of manganese. The poisons were deemed suitable if (i) they did not complex Mn(II) more strongly than the ion-exchange resin Chelex 100, (ii) they did not interfere in the adsorption of /sup 54/Mn(II) onto synthetic deltaMnO/sub 2/ (manganate), (iii) they did not cause desorption of /sup 54/Mn(II) which had been preadsorbed onto synthetic manganate, and (iv) they did not solubilize synthetic /sup 54/manganate. In addition, several known chelators, reducing agents, and buffers normally added to microbiological growth media or used in biochemical assays were tested. Most additions interfered to some extent with manganese chemistry. However, at least one inhibitor, sodium azide, or a mixture of sodium azide, penicillin, and tetracycline was shown to be appropriate for use in field studies of /sup 54/Mn(II) binding. Formaldehyde could also be used in short incubations (1 to 3 h) but was not suitable for longer time course studies. The method was applied to studies of Mn(II) precipitation in Saanich Inlet, British Columbia, Canada. Bacteria were shown to significantly enhance the rate of Mn(II) removal from solution in the manganese-rich particulate layer which occurs just above the oxygen-hydrogen sulfide interface in the water column. 23 references.
Effect of dietary pectin on iron absorption and turnover in the rat
Baig, M.M.; Burgin, C.W.; Cerda, J.J.
The influence of dietary pectin on iron absorption and retention was studied in rats. Basal diet with low and normal iron levels were fed with and without addition of 2% citrus pectin. After 40 days rats were fasted for 24 hours and were given /sup 59/Fe in dilute HCl with or without 2% pectin by gavage. Whole-body counting techniques were employed to monitor /sup 59/Fe absorption and turnover. Rats maintained on low iron diet absorbed and retained a much higher proportion of /sup 59/Fe than rats maintained on normal level of iron. Dietary pectin at the level fed in this study had no influence on iron uptake and/or turnover in rats.
Extracellular killing of inhaled pneumococci in rats
Coonrod, J.D.; Marple, S.; Holmes, G.P.; Rehm, S.R.
Early clearance of inhaled Staphylococcus aureus is believed to be caused by phagocytosis by alveolar macrophages. In murine models inhaled pneumococci are cleared even more rapidly than S. aureus. Conventional opsonins appear to play no role in this clearance, and recently it has been shown that murine alveolar lining material contains free fatty acids and other soluble factors that are directly bactericidal for pneumococci. To determine whether non-phagocytic factors are involved in pneumococcal clearance, we compared the site of killing of inhaled pneumococci and S. aureus in rats using histologic methods and bronchoalveolar lavage. Spontaneous lysis of pneumococci was prevented by use of autolysin-defective pneumococci or by substitution of ethanolamine for choline in the cell wall. Histologic studies showed that the percent of inhaled staphylococci associated with alveolar macrophages always exceeded the percent of staphylococci cleared, whereas there was little association of pneumococci with macrophages during clearance. Analysis of the intracellular or extracellular location of iron 59 in bronchoalveolar lavage fluid of rats that had inhaled aerosols of /sup 59/Fe-labeled bacteria suggested that staphylococci were killed predominantly in macrophages and pneumococci in the extracellular space. When /sup 59/Fe-labeled pneumococci or staphylococci were ingested and killed by macrophages in vitro, the /sup 59/Fe remained with the macrophages, suggesting that the extracellular location of /sup 59/Fe during pneumococcal killing in vivo was not caused by rapid turnover of /sup 59/Fe in macrophages. Studies of the site of killing of inhaled type 25 pneumococci labeled exclusively in the cell wall with carbon 14-ethanolamine confirmed the results obtained with /sup 59/Fe-labeled pneumococci. Thus, early killing of inhaled pneumococci, unlike staphylococci, appears to take place outside of macrophages.
Effect of syngeneic marrow injection upon recovery in sub- and near-lethally irradiated mice
Boggs, S.S.; Boggs, D.R.; Patrene, K.D.
Mice were given sub-lethal (200-600 cGy) or near-lethal (800 cGy) whole body irradiation and the effect of injecting syngeneic marrow on subsequent hematopoietic recovery was studied. Marrow cell injection enhanced erythropoietic recovery after sub-lethal irradiation as reflected in hematocrit values and rate of appearance of /sup 59/Fe-labeled red cells in blood. However, this enhanced erythropoiesis was only seen in the spleen, and /sup 59/Fe uptake in marrow was reduced. When the irradiation dose was kept constant and the marrow dose increased from 10(5) to 10(6) to 10(7) cells, there was a somewhat erratic increase in spleen /sup 59/Fe and a decrease in marrow /sup 59/Fe uptake. When marrow cell number was kept constant and the dose of irradiation was increased from 200 to 400 to 600 to 800 cGy, there was an exponential increase in spleen /sup 59/Fe uptake but the marrow /sup 59/Fe uptake changed from depressed after lower doses to increased after 800 cGy. Cell injection after sub-lethal irradiation did not increase or decrease granulocytopoiesis. Injection of irradiated marrow cells also reduced marrow erythropoiesis and this was evident after both sub- and near-lethal irradiation. However, injection of irradiated cells did not increase splenic erythropoiesis. Following splenectomy, the depressed marrow erythropoiesis attending injection of viable cells was virtually eliminated but no increase was seen. These data suggest that the injection of autologous or syngeneic marrow may not be effective as a means of accelerating hematopoietic recovery after irradiation unless near-lethal or lethal dose have been received.
Iron levels change in larval Heliothis virescens tissues following baculovirus infection
Technology Transfer Automated Retrieval System (TEKTRAN)
Inductively-coupled plasma mass spectrometry (ICP-MS) and 59Fe radiotracers were used to investigate changes in levels of iron (Fe) in the tissues of Heliothis virescens following baculovirus infection. Fe concentrations were determined by ICP-MS in hemolymph collected from 4th instar larvae infect...
Examination of the mechanism of action of nitrogen monoxide on iron uptake from transferrin.
Watts, R N; Richardson, D R
Nitrogen monoxide (NO) exerts many of its functions by binding to iron (Fe) in the active sites of a number of key proteins. Previously we have shown that NO produced by NO-generating agents decreased cellular Fe uptake from transferrin (Tf). However, the mechanism of this effect was not elucidated. In this study we examined the possible mechanisms whereby NO could interfere with Fe uptake. Our experiments demonstrate that NO produced by the NO generator S-nitroso-N-acetylpenicillamine was slightly more effective than the Fe chelator deferoxamine at reducing iron 59 uptake from 59Fe-labeled Tf by LMTK- fibroblasts. Other NO generators including S-nitrosoglutathione (GSNO) and spermine-NONOate also decreased 59Fe uptake from 59Fe-labeled Tf. In contrast, precursors of these compounds that do not release NO had no effect. When the RAW264.7 macrophage cell line was activated to produce NO by incubation with lipopolysaccharide or lipopolysaccharide and interferon-gamma, a decrease in 59Fe uptake from 59Fe-labeled Tf was also observed. Experiments with electron paramagnetic resonance spectroscopy and ultraviolet-Vis spectrophotometry demonstrated that NO did not prevent Fe uptake by binding to the Fe-ligating sites of Tf, suggesting that it acted more distally. Because the uptake of Fe is an energy-dependent process, and since NO inhibits mitochondrial respiration, cellular adenosine triphosphate (ATP) was estimated after incubation with GSNO. In the presence of D-glucose (D-G), GSNO reduced ATP levels by 35% as compared with the control, while in the absence of D-G, GSNO reduced ATP by 72%. When the same experiments were performed with D-fructose (D-F), which cannot be efficiently metabolized by fibroblasts, no "rescue" effect was observed on ATP levels. The addition of D-G to GSNO prevented the decrease in 59Fe uptake from 59Fe-labeled Tf while D-F did not, in good correlation with their effects on ATP levels. These results suggest that D-G acts as a salvage
Comparison of the biodistribution of manganese-54 DTPA and gadolinium-153 DTPA in dogs.
Boudreau, R J; Burbidge, S; Sirr, S; Loken, M K
The biodistribution of [54Mn]DTPA and [153Gd]DTPA dimeglumine were investigated and compared following i.v. administration to fasting anesthetized dogs. Unlike most previously reported metal ion-DTPA complexes, [54Mn]DTPA showed high uptakes in several organs including the liver, bile, pancreas, bowel, and kidney. This uptake was independent of the pH of the injected solution. Accumulation in these organs suggests a potential role for [Mn]DTPA as a paramagnetic contrast agent for NMR imaging. With the exception of the kidneys, [153Gd]DTPA showed no evidence of tissue specific uptake over the course of 4 hr, consistent with it being an extracellular ion that is cleared by glomerular filtration. PMID:3819851
Comparison of the biodistribution of manganese-54 DTPA and gadolinium-153 DTPA in dogs
Boudreau, R.J.; Burbidge, S.; Sirr, S.; Loken, M.K.
The biodistribution of (/sup 54/Mn)DTPA and (/sup 153/Gd)DTPA dimeglumine were investigated and compared following i.v. administration to fasting anesthetized dogs. Unlike most previously reported metal ion-DTPA complexes, (/sup 54/Mn)DTPA showed high uptakes in several organs including the liver, bile, pancreas, bowel, and kidney. This uptake was independent of the pH of the injected solution. Accumulation in these organs suggests a potential role for (Mn)DTPA as a paramagnetic contrast agent for NMR imaging. With the exception of the kidneys, (/sup 153/Gd)DTPA showed no evidence of tissue specific uptake over the course of 4 hr, consistent with it being an extracellular ion that is cleared by glomerular filtration.
Influence of elastase-induced emphysema and the inhalation of an irritant aerosol on deposition and retention of an inhaled insoluble aerosol in Fischer-344 rats
Damon, E.G.; Mokler, B.V.; Jones, R.K.
The purpose of this study was to assess the effects of elastase-induced pulmonary emphysema and the inhalation of an irritant aerosol (Triton X-100, a nonionic surfactant similar to those used in a number of pressurized consumer products) on pulmonary deposition and retention of an insoluble test aerosol, /sup 59/FE-labeled Fe/sub 2/O/sub 3/. Untreated rats or rats pretreated by intratracheal in stillation with elastase were exposed to an aerosol of /sup 59/Fe-labeled Fe/sub 2/O/sub 3/ either 18 hr or 7 days after exposure to aerosslized Triton X-100 which was administered in doses of 20, 100, or 200 ..mu..g/g of lung. Rats pretreated with elastase had significantly lower pulmonary deposition of /sup 59/Fe than the untreated controls (p < 0.005). Pulmonary deposition of Fe/sub 2/O/sub 3/ was unaffected by pretreatment with Triton X-100. Elastase treatment alone had no effect on retention of Fe/sub 2/O/sub 3/. Triton X-100 administered 18 hr prior to exposure of rats to Fe/sub 2/O/sub 3/ aerosol resulted in dose-related increases in whole-body retention of /sup 59/Fe. When rats were exposed to Triton X-100 7 days before exposure to Fe/sub 2/O/sub 3/, increased retention of /sup 59/Fe was noted only in those treated at the highest Triton X-100 dose level (200 ..mu..g/g). 20 references, 5 tables.
Measurement of absorbed dose rate of gamma radiation for lead compounds
NASA Astrophysics Data System (ADS)
Rudraswamy, B.; Dhananjaya, N.; Manjunatha, H. C.
An attempt has been made to estimate the absorbed dose rate using both theoretical and measured mass energy attenuation coefficient of gamma for the lead compounds such as PbNO 3, PbCl 2, PbO 2 and PbO using various gamma sources such as 22Na (511, 1274), 137Cs (661.6), 54Mn (835) and 60Co (1173, 1332 keV).
For the conditioning of spent resins contaminated with radionuclides, such as: 137Cs, 134Cs, 60Co, 58Co, 57Co, 54Mn, etc., techniques of direct immobilization in cement, bitumen and organic polymers have been tested. The selected process was the bituminization using industrial bitumen, I 60-70, made in Romania, which had very good characteristics. The paper presents stages of the research project, technical conditions for the process and advantages of the bituminization of spent resins.
The efficiency variation method for 4pibeta-gamma coincidence counting by ink-jet printing.
Sato, Y; Yamada, T; Hata, T; Moriyama, K; Yunoki, A; Hino, Y
In order to vary the counting efficiencies in the 4pibeta-gamma coincidence extrapolation technique, a radioactive source was coated directly with varying amounts of an electrical conducting pigment using an ink-jet printer. This method can be used to efficiently prepare the multiple sources needed to generate efficiency extrapolation curves, and was successfully applied to the standardization of a (54)Mn source. PMID:18339552
Kinetic assessment of manganese using magnetic resonance imaging in the dually perfused human placenta in vitro
Miller, R.K.; Mattison, D.R.; Panigel, M.; Ceckler, T.; Bryant, R.; Thomford, P.
The transfer and distribution of paramagnetic manganese was investigated in the dually perfused human placenta in vitro (using 10, 20, 100 ..mu..M Mn with and without /sup 54/Mn) using magnetic resonance imaging (MRI) and conventional radiochemical techniques. The human placenta concentrated /sup 54/Mn rapidly during the first 15 min of perfusion and by 4 hr was four times greater than the concentrations of Mn in the maternal perfusate, while the concentration of Mn in the fetal perfusate was 25% of the maternal perfusate levels. Within placentae, 45% of the /sup 54/Mn was free in the 100,000g supernatant, with 45% in the 1000g pellet. The magnetic field dependence of proton nuclear spin-lattice relaxation time (T/sub 1/) in placental tissue supports this Mn binding. Mn primarily affected the MRI partial saturation rather than spin-echo images of the human placenta, which provided for the separation of perfusate contributions from those produced by Mn. The washout of the Mn from the placenta was slow compared with its uptake, as determined by MRI. Thus, Mn was concentrated by the human placenta, but transfer of Mn across the placenta was limited in either direction. These studies also illustrate the opportunity for studies of human placental function using magnetic resonance imaging as a noninvasive biomarker.
Study of the Influence of the Source Quality on the Determination of the Shape Factor of Beta Spectra
NASA Astrophysics Data System (ADS)
Le-Bret, C.; Loidl, M.; Rodrigues, M.; Mougeot, X.; Bouchard, J.
We are developing metallic magnetic calorimeters for beta spectrometry with the aim of determining the shape factors of beta spectra. The beta emitter is enclosed inside the detector absorber and the absorber size is chosen such that the detection efficiency is close to 100% for the entire spectrum. The nature of the deposit of the beta emitter is critical for precise measurement. A dependence of the shape of the spectrum on the quality of the source has been observed, supposedly due to interactions between the electrons and the deposit itself. We chose for this comparative study a nuclide with an allowed transition whose theoretical spectrum is relatively well-known, 63Ni, a pure beta emitter with an endpoint energy of 66.98 keV. Results of measurements of 63Ni deposited with different techniques are presented and compared to each other and to the theoretical spectrum.
The detection of energetic materials with a laser ionization ion mobility spectrometer
NASA Astrophysics Data System (ADS)
Clark, Alistair; Deas, Robert M.; Kosmidis, Constantinos; Ledingham, Kenneth W. D.; Marshall, Archibald; Singhal, Ravi P.
Laser induced multiphoton ionization (MPI) has been used to produce positive and negative ions at atmospheric pressure in an ion mobility spectrometer. This paper deals particularly with the application of this technique to the ultra-trace detection of a number of energetic materials such as RDX and PETN. In conventional ion mobility spectrometry (IMS), a radioactive 63Ni β-foil is used as the ionization source. The laser IMS spectra will be compared with the 63Ni spectra and it will be shown that the analyte ions produced by laser ionization have a wavelength dependent fingerprint which provides an additional degree of selectivity. It is felt that this new approach to IMS will develop considerably the scope and applicability of this powerful technique.
Uptake and transport of radioactive nickel and cadmium into three vegetables after wet aerial contamination.
Fismes, Joëlle; Echevarria, Guillaume; Leclerc-Cessac, Elisabeth; Morel, Jean Louis
Knowledge of radionuclide or trace element retention and translocation to plants following an aerial contamination event, for example, sprinkling with contaminated water, is necessary for the evaluation of human exposure through consumption of contaminated vegetables. The fate of 63Ni and 109Cd in all plant parts of three different vegetables after wet deposition on leaves or on fruits was studied. Lettuce (Lactuca sativa L.), radish (Raphanus sativus L.), and bean (Phaseolus vulgaris L.) grown under controlled conditions in a growth chamber were contaminated with 63Ni and 109Cd either on leaves, by means of two different contamination methods (a single early contamination and a repetitive one), or on bean husks (third contamination method: a single contamination at a late stage). Spiked and nonspiked organs were harvested at maturity and radionuclide contents were measured. The fraction retained was on average 56% of the initially administered doses of 63Ni and 87% of 109Cd. The leaf-to-other organ translocation factor was considerably higher for 63Ni (on average 43% of retained radioactivity) than for 109Cd (8%). Nickel-63 migrated throughout the whole plant following foliar contamination, and mainly toward young leaves, seeds in formation, and sink organs, whereas 109Cd migrated to a much lesser extent and only to the organs that were closest to the spiked one, and not at all into fruit. After a fruit contamination event, both radionuclides were translocated into the seeds of spiked fruits. Radionuclide retention and translocation were not affected by plant species, but principally by the type of organ contaminated. PMID:16091602
Fuel cell using a hydrogen generation system
Dentinger, Paul M.; Crowell, Jeffrey A. W.
A system is described for storing and generating hydrogen and, in particular, a system for storing and generating hydrogen for use in an H.sub.2/O.sub.2 fuel cell. The hydrogen storage system uses beta particles from a beta particle emitting material to degrade an organic polymer material to release substantially pure hydrogen. In a preferred embodiment of the invention, beta particles from .sup.63Ni are used to release hydrogen from linear polyethylene.
Hydrogen storage and generation system
Dentinger, Paul M.; Crowell, Jeffrey A. W.
A system for storing and generating hydrogen generally and, in particular, a system for storing and generating hydrogen for use in an H.sub.2/O.sub.2 fuel cell. The hydrogen storage system uses the beta particles from a beta particle emitting material to degrade an organic polymer material to release substantially pure hydrogen. In a preferred embodiment of the invention, beta particles from .sup.63Ni are used to release hydrogen from linear polyethylene.
Design and simulation of betavoltaic angle sensor Based on ⁶³Ni-Si.
Nejad, Gholam Reza Ghasemi; Rahmani, Faezeh
A theoretical design and simulation of betavoltaic angle sensor (beta-AS) based on (63)Ni-Si using MCNP code is presented in this article. It can measure the full angle of 0-360° in the temperature range of 233-353 K. Beta-AS is composed of semicircular (63)Ni as the beta source, which rotates along the circular (four-quadrant) surface of Si as a semiconductor (in p-n structure), so that the change in the source angle in relation to Si surface can be measured based on the changes in V(oc) observed in each quadrant of Si. For better performance, characteristics of Si and (63)Ni have been optimized: N(D) and N(A) values of 8e19 and 4e18 cm(-3) (donor and acceptor doping concentration in Si, respectively), source thickness and activity of 1.5 µm and 18 mCi, respectively. The relation between angle and V(oc) is also investigated. The maximum difference between measured and real values of angle (the worst case, i.e., 0.18° for the angle of 45°) occurs at 233 K. It has been shown that sensitivity of the sensor decreases with an increase of angle. The results also show that the change in activity does not affect the sensitivity. PMID:26609684
Measuring fast neutrons in Hiroshima at distances relevant to atomic-bomb survivors.
Straume, T; Rugel, G; Marchetti, A A; Rühm, W; Korschinek, G; McAninch, J E; Carroll, K; Egbert, S; Faestermann, T; Knie, K; Martinelli, R; Wallner, A; Wallner, C
Data from the survivors of the atomic bombs serve as the major basis for risk calculations of radiation-induced cancer in humans. A controversy has existed for almost two decades, however, concerning the possibility that neutron doses in Hiroshima may have been much larger than estimated. This controversy was based on measurements of radioisotopes activated by thermal neutrons that suggested much higher fluences at larger distances than expected. For fast neutrons, which contributed almost all the neutron dose, clear measurement validation has so far proved impossible at the large distances (900 to 1,500 m) most relevant to survivor locations. Here, the first results are reported for the detection of 63Ni produced predominantly by fast neutrons (above about 1 MeV) in copper samples from Hiroshima. This breakthrough was made possible by the development of chemical extraction methods and major improvements in the sensitivity of accelerator mass spectrometry for detection of 63Ni atoms (refs 8-11). When results are compared with 63Ni activation predicted by neutron doses for Hiroshima survivors, good agreement is observed at the distances most relevant to survivor data. These findings provide, for the first time, clear measurement validation of the neutron doses to survivors in Hiroshima. PMID:12891354
Solving the stellar 62Ni problem with AMS
NASA Astrophysics Data System (ADS)
Dillmann, I.; Faestermann, T.; Korschinek, G.; Lachner, J.; Maiti, M.; Poutivtsev, M.; Rugel, G.; Walter, S.; Käppeler, F.; Erhard, M.; Junghans, A. R.; Nair, C.; Schwengner, R.; Wagner, A.
An accurate knowledge of the neutron capture cross sections of 62,63Ni is crucial since both isotopes take key positions which affect the whole reaction flow in the weak s process up to A≈90. No experimental value for the 63Ni(n,γ) cross section exists so far, and until recently the experimental values for 62Ni(n,γ) at stellar temperatures (kT=30keV) ranged between 12 and 37 mb. This latter discrepancy could now be solved by two activations with following AMS using the GAMS setup at the Munich tandem accelerator which are also in perfect agreement with a recent time-of-flight measurement. The resulting (preliminary) Maxwellian cross section at kT = 30 keV was determined to be <σ>=23.4±4.6mb. Additionally, we have measured the 64Ni(γ,n)63Ni cross section close to threshold. Photoactivations at 13.5 MeV, 11.4 MeV and 10.3 MeV were carried out with the ELBE accelerator at Forschungszentrum Dresden-Rossendorf. A first AMS measurement of the sample activated at 13.5 MeV revealed a cross section smaller by more than a factor of 2 compared to NON-SMOKER predictions.
Atmospheric pressure chemical ionization studies of non-polar isomeric hydrocarbons using ion mobility spectrometry and mass spectrometry with different ionization techniques
NASA Technical Reports Server (NTRS)
Borsdorf, H.; Nazarov, E. G.; Eiceman, G. A.
The ionization pathways were determined for sets of isomeric non-polar hydrocarbons (structural isomers, cis/trans isomers) using ion mobility spectrometry and mass spectrometry with different techniques of atmospheric pressure chemical ionization to assess the influence of structural features on ion formation. Depending on the structural features, different ions were observed using mass spectrometry. Unsaturated hydrocarbons formed mostly [M - 1]+ and [(M - 1)2H]+ ions while mainly [M - 3]+ and [(M - 3)H2O]+ ions were found for saturated cis/trans isomers using photoionization and 63Ni ionization. These ionization methods and corona discharge ionization were used for ion mobility measurements of these compounds. Different ions were detected for compounds with different structural features. 63Ni ionization and photoionization provide comparable ions for every set of isomers. The product ions formed can be clearly attributed to the structures identified. However, differences in relative abundance of product ions were found. Although corona discharge ionization permits the most sensitive detection of non-polar hydrocarbons, the spectra detected are complex and differ from those obtained with 63Ni ionization and photoionization. c. 2002 American Society for Mass Spectrometry.
Betavoltaic effect in titanium dioxide nanotube arrays under build-in potential difference
NASA Astrophysics Data System (ADS)
Zhang, Qiang; Chen, Ranbin; San, Haisheng; Liu, Guohua; Wang, Kaiying
We report the fabrication of sandwich-type metal/TiO2 nanotube (TNT) array/metal structures as well as their betavoltaic effects under build-in voltage through contact potential difference. The sandwiched structure is integrated by immobilized TNT arrays on Ti foil with radioisotope 63Ni planar source on Ni substrate (Ni-63Ni/TNT array/Ti). Under irradiation of the 63Ni source with activity of 8 mCi, the structure (TNT diameter ∼ 130 nm, length ∼ 11 μm) presents optimum energy conversion efficiency of 7.30% with open-circuit voltage of 1.54 V and short-circuit current of 12.43 nA. The TNT arrays exhibit a highly potential for developing betavoltaic batteries due to its wide band gap and nanotube array configuration. The TNT-betavoltaic concept offers a facile solution for micro/nano electronics with high efficiency and long life-time instead of conventional planar junction-type batteries.
Fast neutrons measured in copper from the Hiroshima atomic bomb dome.
Marchetti, A A; McAninch, J E; Rugel, G; Rühm, W; Korschinek, G; Martinelli, R E; Faestermann, T; Knie, K; Egbert, S D; Wallner, A; Wallner, C; Tanaka, K; Endo, S; Hoshi, M; Shizuma, K; Fujita, S; Hasai, H; Imanaka, T; Straume, T
The first measurements of (63)Ni produced by A-bomb fast neutrons (above approximately 1 MeV) in copper samples from Hiroshima encompassed distances from approximately 380 to 5062 m from the hypocenter (the point on the ground directly under the bomb). They included the region of interest to survivor studies (approximately 900 to 1500 m) and provided the first direct validation of fast neutrons in that range. However, a significant measurement gap remained between the hypocenter and 380 m. Measurements close to the hypocenter are important as a high-value anchor for the slope of the curve for neutron activation as a function of distance. Here we report measurements of (63)Ni in copper samples from the historic Hiroshima Atomic Bomb Dome, which is located approximately 150 m from the hypocenter. These measurements extend the range of our previously published data for (63)Ni providing a more comprehensive and consistent A-bomb activation curve. The results are also in good agreement with calculations based on the current dosimetry system (DS02) and give further experimental support to the accuracy of this system that forms the basis for radiation risk estimates worldwide. PMID:19138052
Transferrin binding and iron uptake by mouse lymph node cells during transformation in response to concanavalin A.
Brock, J H; Rankin, M C
Mouse lymph node cells cultured with Concanavalin A (Con A) in serum-free medium containing 59Fe-transferrin took up 59Fe more rapidly than cells cultured without Con-A. Uptake of iron commenced rapidly and preceded the onset of DNA synthesis in stimulated cells. Total uptake of transferrin during culture was much lower than that of iron, indicating that cells could remove iron from transferrin. The released transferrin appeared to be undergraded. Lymphoblasts bound six times more transferrin per cell than small lymphocytes. Lymphocytes also took up iron from citrate and nitrilotriacetate complexes, and iron so acquired was not readily removed by desferrioxamine, indicating that it was not bound extracellularly. PMID:7251060
Lattice location and thermal stability of implanted Fe in ZnO
Rita, E.; Wahl, U.; Correia, J.G.; Alves, E.; Soares, J.C.
The emission channeling technique was applied to evaluate the lattice location of implanted {sup 59}Fe in single-crystalline ZnO. The angular distribution of {beta}{sup -} particles emitted by {sup 59}Fe was monitored with a position-sensitive electron detector, following 60 keV low dose (2.0x10{sup 13} cm{sup -2}) room-temperature implantation of the precursor isotope {sup 59}Mn. The emission patterns around the [0001], [1102],[1101], and [2113] directions revealed that following annealing at 800 deg. C, 95(8)% of the Fe atoms occupy ideal substitutional Zn sites with rms displacements of 0.06-0.09 A.
Prion Protein Promotes Kidney Iron Uptake via Its Ferrireductase Activity*
Haldar, Swati; Tripathi, Ajai; Qian, Juan; Beserra, Amber; Suda, Srinivas; McElwee, Matthew; Turner, Jerrold; Hopfer, Ulrich; Singh, Neena
Brain iron-dyshomeostasis is an important cause of neurotoxicity in prion disorders, a group of neurodegenerative conditions associated with the conversion of prion protein (PrPC) from its normal conformation to an aggregated, PrP-scrapie (PrPSc) isoform. Alteration of iron homeostasis is believed to result from impaired function of PrPC in neuronal iron uptake via its ferrireductase activity. However, unequivocal evidence supporting the ferrireductase activity of PrPC is lacking. Kidney provides a relevant model for this evaluation because PrPC is expressed in the kidney, and ∼370 μg of iron are reabsorbed daily from the glomerular filtrate by kidney proximal tubule cells (PT), requiring ferrireductase activity. Here, we report that PrPC promotes the uptake of transferrin (Tf) and non-Tf-bound iron (NTBI) by the kidney in vivo and mainly NTBI by PT cells in vitro. Thus, uptake of 59Fe administered by gastric gavage, intravenously, or intraperitoneally was significantly lower in PrP-knock-out (PrP−/−) mouse kidney relative to PrP+/+ controls. Selective in vivo radiolabeling of plasma NTBI with 59Fe revealed similar results. Expression of exogenous PrPC in immortalized PT cells showed localization on the plasma membrane and intracellular vesicles and increased transepithelial transport of 59Fe-NTBI and to a smaller extent 59Fe-Tf from the apical to the basolateral domain. Notably, the ferrireductase-deficient mutant of PrP (PrPΔ51–89) lacked this activity. Furthermore, excess NTBI and hemin caused aggregation of PrPC to a detergent-insoluble form, limiting iron uptake. Together, these observations suggest that PrPC promotes retrieval of iron from the glomerular filtrate via its ferrireductase activity and modulates kidney iron metabolism. PMID:25572394
Prion protein promotes kidney iron uptake via its ferrireductase activity.
Haldar, Swati; Tripathi, Ajai; Qian, Juan; Beserra, Amber; Suda, Srinivas; McElwee, Matthew; Turner, Jerrold; Hopfer, Ulrich; Singh, Neena
Brain iron-dyshomeostasis is an important cause of neurotoxicity in prion disorders, a group of neurodegenerative conditions associated with the conversion of prion protein (PrP(C)) from its normal conformation to an aggregated, PrP-scrapie (PrP(Sc)) isoform. Alteration of iron homeostasis is believed to result from impaired function of PrP(C) in neuronal iron uptake via its ferrireductase activity. However, unequivocal evidence supporting the ferrireductase activity of PrP(C) is lacking. Kidney provides a relevant model for this evaluation because PrP(C) is expressed in the kidney, and ∼370 μg of iron are reabsorbed daily from the glomerular filtrate by kidney proximal tubule cells (PT), requiring ferrireductase activity. Here, we report that PrP(C) promotes the uptake of transferrin (Tf) and non-Tf-bound iron (NTBI) by the kidney in vivo and mainly NTBI by PT cells in vitro. Thus, uptake of (59)Fe administered by gastric gavage, intravenously, or intraperitoneally was significantly lower in PrP-knock-out (PrP(-/-)) mouse kidney relative to PrP(+/+) controls. Selective in vivo radiolabeling of plasma NTBI with (59)Fe revealed similar results. Expression of exogenous PrP(C) in immortalized PT cells showed localization on the plasma membrane and intracellular vesicles and increased transepithelial transport of (59)Fe-NTBI and to a smaller extent (59)Fe-Tf from the apical to the basolateral domain. Notably, the ferrireductase-deficient mutant of PrP (PrP(Δ51-89)) lacked this activity. Furthermore, excess NTBI and hemin caused aggregation of PrP(C) to a detergent-insoluble form, limiting iron uptake. Together, these observations suggest that PrP(C) promotes retrieval of iron from the glomerular filtrate via its ferrireductase activity and modulates kidney iron metabolism. PMID:25572394
Nitrogen monoxide (NO)-mediated iron release from cells is linked to NO-induced glutathione efflux via multidrug resistance-associated protein 1
Watts, Ralph N.; Hawkins, Clare; Ponka, Prem; Richardson, Des R.
Nitrogen monoxide (NO) plays a role in the cytotoxic mechanisms of activated macrophages against tumor cells by inducing iron (Fe) release. We have shown that NO-mediated Fe efflux from cells required glutathione (GSH), and we have hypothesized that a GS–Fe–NO complex was released. Hence, we studied the role of the GSH-conjugate transporter multidrug resistance-associated protein 1 (MRP1) in NO-mediated Fe efflux. MCF7-VP cells overexpressing MRP1 exhibited a 3- to 4-fold increase in NO-mediated 59Fe and GSH efflux compared with WT cells (MCF7-WT) over 4 h. Similar results were found for other MRP1-overexpressing cell types but not those expressing another drug efflux pump, P-glycoprotein. NO-mediated 59Fe and GSH efflux were temperature- and energy-dependent and were significantly decreased by the GSH-depleting agent and MRP1 transport inhibitor l-buthionine-[S,R]-sulfoximine. Other MRP1 inhibitors, MK571, probenecid, and difloxacin, significantly inhibited NO-mediated 59Fe release. EPR spectroscopy demonstrated the dinitrosyl-dithiol-Fe complex (DNIC) peak in NO-treated cells was increased by MRP1 inhibitors, indicating inhibited DNIC transport from cells. The extent of DNIC accumulation correlated with the ability of MRP1 inhibitors to prevent NO-mediated 59Fe efflux. MCF7-VP cells were more sensitive than MCF7-WT cells to growth inhibition by effects of NO, which was potentiated by l-buthionine-[S,R]-sulfoximine. These data indicate the importance of GSH in NO-mediated inhibition of proliferation. Collectively, NO stimulates Fe and GSH efflux from cells via MRP1. Active transport of NO by MRP1 overcomes diffusion that is inefficient and nontargeted, which has broad ramifications for understanding NO biology. PMID:16679408
Tn5 insertion mutants of Pseudomonas aeruginosa deficient in surface expression of ferripyochelin-binding protein
Sokol, P.A.
Transposon (Tn5) insertion mutants were isolated in Pseudomonas aeruginosa PAO. These mutants were screened for expression of the ferripyochelin-binding protein with monoclonal antibody in a whole-cell immunoblot assay. Fourteen mutants were identified which did not express ferripyochelin-binding protein on the cell surface. These mutants did not take up /sup 59/Fe-labeled pyochelin and grew slowly in the presence of iron chelators.
Ferroportin and Exocytoplasmic Ferroxidase Activity Are Required for Brain Microvascular Endothelial Cell Iron Efflux*
McCarthy, Ryan C.; Kosman, Daniel J.
The mechanism(s) of iron flux across the brain microvasculature endothelial cells (BMVEC) of the blood-brain barrier remains unknown. Although both hephaestin (Hp) and the ferrous iron permease ferroportin (Fpn) have been identified in BMVEC, their roles in iron efflux have not been examined. Using a human BMVEC line (hBMVEC), we have demonstrated that these proteins are required for iron efflux from these cells. Expression of both Hp and Fpn protein was confirmed in hBMVEC by immunoblot and indirect immunofluorescence; we show that hBMVEC express soluble ceruloplasmin (Cp) transcript as well. Depletion of endogenous Hp and Cp via copper chelation leads to the reduction of hBMVEC Fpn protein levels as well as a complete inhibition of 59Fe efflux. Both hBMVEC Fpn protein and 59Fe efflux activity are restored upon incubation with 6.6 nm soluble plasma Cp. These results are independent of the source of cell iron, whether delivered as transferrin- or non-transferrin-bound 59Fe. Our results demonstrate that iron efflux from hBMVEC Fpn requires the action of an exocytoplasmic ferroxidase, which can be either endogenous Hp or extracellular Cp. PMID:23640881
Human macrophage hemoglobin-iron metabolism in vitro
Custer, G.; Balcerzak, S.; Rinehart, J.
An entirely in vitro technique was employed to characterize hemoglobin-iron metabolism by human macrophages obtained by culture of blood monocytes and pulmonary alveolar macrophages. Macrophages phagocytized about three times as many erythrocytes as monocytes and six times as many erythrocytes as pulmonary alveolar macrophages. The rate of subsequent release of /sup 59/Fe to the extracellular transferrin pool was two- to fourfold greater for macrophages as compared to the other two cell types. The kinetics of /sup 59/Fe-transferrin release were characterized by a relatively rapid early phase (hours 1-4) followed by a slow phase (hours 4-72) for all three cell types. Intracellular movement of iron was characterized by a rapid shift from hemoglobin to ferritin that was complete with the onset of the slow phase of extracellular release. A transient increase in /sup 59/Fe associated with an intracellular protein eluting with transferrin was also observed within 1 hour after phagocytosis. The process of hemoglobin-iron release to extracellular transferrin was inhibited at 4 degrees C but was unaffected by inhibitory of protein synthesis, glycolysis, microtubule function, and microfilament function. These data emphasize the rapidity of macrophage hemoglobin iron metabolism, provide a model for characterization of this process in vitro, and in general confirm data obtained utilizing in vivo animal models.
A rapid assay for evaluation of iron-chelating agents in rats
Pippard, M.J.; Johnson, D.K.; Finch, C.A.
The animal assay of potential new iron-chelating agents is at present dependent on cumbersome and imprecise iron balance studies in hypertransfused rodents. We report the development of a radioisotope assay in intact rats based on the transient labeling by ferritin 59Fe of the main source of chelatable iron within hepatocytes. The isotope was maximally available to chelators during the first 6 hr after its injection, nearly all the excretion being in the bile. The bile 59Fe/total iron ratio was independent of both the chelator and its dose. However, in iron-loaded rats, the ratio was reduced, and the isotope excretion was a less sensitive measure of intrahepatic chelation. In the proposed assay, test chelators were given to normal rats 2 hr after an intravenous injection of 59Fe-ferritin. Four hours later, the radioiron in the liver and in the gut gave a sensitive measure of the mobilization of hepatic iron to the bile. In addition, chemical iron determinations identified a small alternative source of urinary chelate with agents known to promote urine excretion in man. The assay gave a rapid and precise screen for chelators given by parenteral and oral routes.
The uptake of iron by reticulocytes. The influence of purification of the ghosts on iron-containing components in the ghost suspension.
von der Heul, C; Kroos, M J; de Jeu-Jaspars, C M; von Eijk, H G
1. Rat reticulocytes previously incubated with ((59)Fe, (125)I)-labelled transferrin were hemolysed to yield labelled ghosts. 2. The solubilized ghosts can be fractionated, by gel filtration on Sepharose 2B and 6B, into several (59)Fe- and (125)I-containing compounds, classified as A, B(1) and B(2). 3. These fractions were prepared from ghosts which were obtained at different centrifugation rates and further purified by sucrose density gradient centrifugation in order to obtain membrane compounds purified from mitochondrial and lysosomal impurities. The influence of these purification steps on the appearance and the (59)Fe/(125)I activity of the three components was investigated. 4. The first Sepharose 2B fraction with high molecular mass, greater than 10(6) daltons, is an intracellular product of mitochondrial and lysosomal origin which precipitates with the membrane fractions during the preparation of the ghost. The first Sepharose 6B fraction, B(1), with M(r) approximately 10(6) seems to be a real membrane component. The second Sepharose 6B fraction, B(2), with M(r) approximately 230 000 represents a real membrane receptor transferrin. PMID:7417439
Iron bioavailability studies as assessed by intrinsic and extrinsic labeling techniques
Johnson, C.D.
Although soybeans are a rich source of iron and incorporation of soy protein into diets is increasing, the presence of phytate or fiber endogenous to the seeds may inhibit total iron absorption from diets including soy protein. Four studies on iron bioavailability as assessed by intrinsic and extrinsic labeling techniques in rats were completed. The effect of previous dietary protein on the absorption of intrinsically /sup 59/Fe labeled defatted soy flour was determined in rats. The results indicated that the type of dietary protein (animal vs. plant) in pre-test diets would have little influence on iron absorption from a single soy protein test meal. Therefore, adaptation of soy protein does not improve bioavailability of iron. Soybean hulls were investigated as a source of iron fortification in bread. The results indicated that retention of /sup 59/Fe from white bread baked with soy hulls did not differ from white bread fortified with bakery grade ferrous sulfate. The effect of endogenous soybean phytate on iron absorption in rats was measured using seeds of varying phytate content and intrinsically labeled with /sup 59/Fe. Increasing concentration of phytate in whole soybean flour had no significant effect on iron absorption.
Bioavailability to rats of iron in six varieties of wheat grain intrinsically labeled with radioiron
House, W.A.; Welch, R.M.
Bioavailability to anemic rats of iron in six varieties of wheat grain was assessed by a whole-body radioassay procedure. Intrinsically labeled kernels were harvested from plants grown in /sup 59/Fe-labeled nutrient solutions. The varieties used were selected from 18 varieties of field-grown wheat grain that were analyzed for iron, protein and phytate content. Concentrations of iron, phytate and protein in grain of field-grown varieties ranged from 34 to 55 ppm, 0.7 to 1.2% dry wt and 11.3 to 15.4% dry wt, respectively. In grain from varieties grown in nutrient solutions, iron, phytate and protein concentrations ranged from 35 to 50 ppm, 1 to 1.2% dry wt, and 13.8 to 16.8% dry wt, respectively. Depending on the variety of intrinsically labeled grain fed in test meals to anemic rats (hemoglobin averaged 5.8 g/dL), absorption of /sup 59/Fe ranged from about 62 to 74% of the dose; differences among varieties were not significant (P greater than 0.05). Rats fed /sup 59/Fe-labeled FeCl/sub 3/ absorbed about 71% of the dose, which was similar to the average amount (69% of dose) absorbed by rats fed wheat. We concluded that selection of wheat varieties for increased yield or protein content has not adversely affected the bioavailability of iron in the grain.
The influence of high iron diet on rat lung manganese absorption
Thompson, Khristy; Molina, Ramon; Donaghey, Thomas; Brain, Joseph D.; Wessling-Resnick, Marianne . E-mail: email@example.com
Individuals chronically exposed to manganese are at high risk for neurotoxic effects of this metal. A primary route of exposure is through respiration, although little is known about pulmonary uptake of metals or factors that modify this process. High dietary iron levels inversely affect intestinal uptake of manganese, and a major goal of this study was to determine if dietary iron loading could increase lung non-heme iron levels and alter manganese absorption. Rats were fed a high iron (1% carbonyl iron) or control diet for 4 weeks. Lung non-heme iron levels increased {approx}2-fold in rats fed the high iron diet. To determine if iron-loading affected manganese uptake, {sup 54}Mn was administered by intratracheal (it) instillation or intravenous (iv) injection for pharmacokinetic studies. {sup 54}Mn absorption from the lungs to the blood was lower in it-instilled rats fed the 1% carbonyl iron diet. Pharmacokinetics of iv-injected {sup 54}Mn revealed that the isotope was cleared more rapidly from the blood of iron-loaded rats. In situ analysis of divalent metal transporter-1 (DMT1) expression in lung detected mRNA in airway epithelium and bronchus-associated lymphatic tissue (BALT). Staining of the latter was significantly reduced in rats fed the high iron diet. In situ analysis of transferrin receptor (TfR) mRNA showed staining in BALT alone. These data demonstrate that manganese absorption from the lungs to the blood can be modified by iron status and the route of administration.
Homeostatic control of manganese excretion in the neonatal rat
Ballatori, N.; Miles, E.; Clarkson, T.W.
Previous studies in neonatal and suckling animals showed that immature animals have a greatly diminished capacity to excrete manganese and therefore were considered to be unable to regulate tissue manganese concentrations. In contrast, the present studies indicate that suckling rats have the capacity to excrete excess manganese at rates nearly comparable to those of adults. Eight- to 10-day-old rats given a tracer dose of /sup 54/MnCl/sub 2/ (essentially carrier free), either via gavage or by intraperitoneal injection showed little elimination of the /sup 54/Mn until the 18-19th day of life, when there was an abrupt increase in the rate of the metal's excretion. However, when manganese was given in doses of 1 and 10 mg/kg, the young animals excreted from 30-70% of the dose in only 4 days, at which time a new rate of excretion was achieved. This enhanced rate of excretion remained constant until the 18-19th day of life, when it was again accelerated. Biliary excretion of manganese, the primary route for the elimination of the metal, was only 30-60% lower in 14-day-old rats compared with adults at doses ranging from tracer to 10 mg /sup 54/Mn/kg. For both the 14-day-old and adult rats, an apparent biliary transport maximum was reached at a dose of 10 mg Mn/kg. These studies indicate that the excretory pathways for manganese are well developed in the neonatal rat. The avid retention of tracer quantities of manganese by the neonate may be a consequence of the scarcity of this essential trace metal in its diet.
Lunar and Planetary Science XXXV: Isotopes in Meteorites
NASA Technical Reports Server (NTRS)
The session"Isotopes in Meteorites" consisted of the following presentations:The Common Property of Isotopic Anomalies in Meteorites; Revised Production Rates for 22Na and 54Mn in Meteorites Using Cross Sections Measured for Neutron-induced Reactions; Modeling of 14C and 10Be Production Rates in Meteorites and Lunar Samples; Investigating Xenon Isotopic Fractionation During Rayleigh-type Distillation; The Mean Life Squared Relationship for Abundances of Extinct Radioactivities; and Magnesium Isotopic Fractionation of Forsterite During Evaporation from Different Crystallographic Surfaces.
Measurements of radiological data of some amino acids in the energy range 0.122-1.330MeV
NASA Astrophysics Data System (ADS)
Lokhande, Rajkumar M.; More, Chaitali V.; Surung, Bharat S.; Raut, Siddheshwar D.; Pawar, Pravina P.
Radiological parameters such as μm, σt, σe, Zeff and Neff of amino acids, namely Lysine (C6H15N2O2), Histidine (C6H9N3O2) and Arginine (C6H15N4O2), were measured using NaI (Tl)-based gamma spectrometry. Radioactive sources used in the study are 57Co, 133Ba, 137Cs, 54Mn, 60Co and 22Na. Gamma ray transmission method in a narrow beam good geometry set up was used in the study. The measured data were compared against XCOM-based data. The agreement is within 2%.
Natural and man-made radionuclides in sediments of an inlet in Rio de Janeiro State, Brazil.
Carvalho, Franciane Martins de; Lauria, Dejanira da Costa; Ribeiro, Fernando Carlos Araújo; Fonseca, Rafael Tonelli; Peres, Sueli da Silva; Martins, Nádia Soido Falcão
The distribution of natural radionuclides (226)Ra, (228)Ra, (40)K and man-made radionuclides ((54)Mn, (60)Co and (137) Cs) in the surface sediments of an inlet of Ribeira Bay were investigated. Sediment samples were collected and analyzed for radionuclides, organic matter, carbonate, sulfate, cationic exchange capacity and grain size composition. The natural radionuclide concentrations ranged from 4.4 to 45, from 10 to 93, from 66 to 1347Bq·kg(-1) dry weight for (226)Ra, (228)Ra and (40)K, respectively. Natural radionuclide concentrations tend to be higher in the silt fraction, which determines their pattern distributions. Only one sample presented measurable concentration for (137)Cs, while (54)Mn was detected in two samples and (60)Co in four sediment samples. Man-made radionuclides present a maximum value of dose external four times lower than the normal background and the potential risk due to the presence of man-made radionuclides in sediments is lower than the risk provided by the natural radionuclides. PMID:27084201
Simulation of Radioactive Corrosion Product in Primary Cooling System of Japanese Sodium-Cooled Fast Breeder Reactor
NASA Astrophysics Data System (ADS)
Matuo, Youichirou; Miyahara, Shinya; Izumi, Yoshinobu
Radioactive Corrosion Product (CP) is a main cause of personal radiation exposure during maintenance with no breached fuel in fast breeder reactor (FBR) plants. The most important CP is 54Mn and 60Co. In order to establish techniques of radiation dose estimation for radiation workers in radiation-controlled areas of the FBR, the PSYCHE (Program SYstem for Corrosion Hazard Evaluation) code was developed. We add the Particle Model to the conventional PSYCHE analytical model. In this paper, we performed calculation of CP transfer in JOYO using an improved calculation code in which the Particle Model was added to the PSYCHE. The C/E (calculated / experimentally observed) value for CP deposition was improved through use of this improved PSYCHE incorporating the Particle Model. Moreover, among the percentage of total radioactive deposition accounted for by CP in particle form, 54Mn was estimated to constitute approximately 20 % and 60Co approximately 40 % in the cold-leg region. These calculation results are consistent with the measured results for the actual cold-leg piping in the JOYO.
Nuclear Data Sheets for A = 54
Dong, Yang; Junde, Huo
The 2005 evaluation for A=54 (2006Hu08) has been updated. Detailed experimental nuclear structure data and decay data for all nuclei with mass chain A=54 are presented in this current evaluation. The new data and information are given in following datasets: {sup 54}Ca: {sup 9}Be({sup 76}Ge, X) and Be({sup 55}Sc, p), ({sup 56}Ti, 2p) {sup 54}Sc: {sup 54}Ca β{sup −} decay and {sup 54}Sc IT decay {sup 54}Ti: {sup 54}Sc β{sup −} decay {sup 54}Cr: {sup 54}Mn ε decay, {sup 56}Fe(μ, nupng), and {sup 238}U({sup 64}Ni, Xγ) {sup 54}Mn: {sup 51}V({sup 20}Ne, Xγ), {sup 55}Mn(p, pn), and {sup 56}Fe(μ, nu2ng) {sup 54}Fe: {sup 58}Ni α decay, {sup 9}Be({sup 55}Co, Xγ), {sup 54}Fe(e, e'), {sup 54}Fe(p, p'), and Coulomb Excitation {sup 54}Co: {sup 54}Ni ε decay, {sup 55}Cu εp decay, {sup 28}Si({sup 32}S, αpnγ), {sup 54}Fe(p,n), and {sup 54}Fe({sup 3}He, t) {sup 54}Ni: {sup 54}Ni IT decay, {sup 55}Zn εp decay, {sup 9}Be({sup 55}Ni, Xγ), and {sup 24}Mg({sup 32}S, Xγ) {sup 54}Zn: Ni({sup 58}Ni, X)
Bioconcentration of Ag, Cd, Co, Mn and Zn in the Mangrove Oyster (Crassostrea gasar) and Preliminary Human Health Risk Assessment: A Radiotracer Study.
Kuranchie-Mensah, Harriet; Teyssié, Jean-Louis; Oberhänsli, François; Tumnoi, Yutthana; Pouil, Simon; Warnau, Michel; Metian, Marc
Bioaccumulation kinetics of five dissolved metals were determined in the mangrove oyster Crassostrea gasar, using corresponding radiotracers ((54)Mn, (57)Co, (65)Zn, (109)Cd and (110m)Ag). Additionally, their bioaccessibility to human consumers was estimated. Results indicated that over a 14-day exposure (54)Mn and (57)Co were linearly concentrated in oysters whereas (109)Cd, (65)Zn and (110m)Ag were starting to saturate (steady-state not reached). Whole-body concentration factors at 14 days (CF14d in toto) ranged from 187 ± 65 to 629 ± 179 with the lowest bioconcentration capacity for Co and the highest for Ag. Depuration kinetics were best described by a double-exponential model with associated biological half-lives ranging from 26 days (Ag) to almost 8 months (Zn and Cd). Bioaccessible fraction of the studied elements was estimated using in vitro digestions, which suggested that oysters consumed seasoned with lemon enhanced the accessibility of Cd, Mn and Zn to human consumers, but not Ag and Co. PMID:27194421
Radionuclide transfer to marine biota species: review of Russian language studies.
Fesenko, S; Fesenko, E; Titov, I; Karpenko, E; Sanzharova, N; Fonseca, A Gondin; Brown, J
An extensive programme of experiments on transfer of radionuclides to aquatic species was conducted in the former USSR starting from the early 1950s. Only a few of these studies were made available in the English language literature or taken into account in international reviews of radionuclide behaviour in marine ecosystems. Therefore, an overview of original information on radionuclide transfer to marine biota species available from Russian language literature sources is presented here. The concentration ratio (CR) values for many radionuclides and for marine species such as: (239)Pu, (106)Ru and (95)Zr (crustacean), (54)Mn, (90)Sr, (95)Nb, (106)Ru, (137)Cs (239)Pu, (241)Am and natural U (molluscs), and (54)Mn, (90)Sr, (137)Cs and (144)Ce (fish) are in good agreement with those previously published, whilst for some of them, in particular, for (32)P and (110)Ag (crustaceans), (35)S (molluscs), (32)P, (35)S, (95)Nb, and (106)Ru (macroalgae) and (60)Co and (239,240)Pu (fish) the data presented here suggest that changes in the default CR reference values presented in recent marine reviews may be required. The data presented here are intended to supplement substantially the CR values being collated within the handbook on Wildlife Transfer Coefficients, coordinated under the IAEA EMRAS II programme. PMID:20798950
Pharmacokinetic Modeling of Manganese III. Physiological Approaches Accounting for Background and Tracer Kinetics
Teeguarden, Justin G.; Gearhart, Jeffrey; Clewell, III, H. J.; Covington, Tammie R.; Nong, Andy; Anderson, Melvin E.
assessments (Dixit et al., 2003). With most exogenous compounds, there is often no background exposure and body concentrations are not under active control from homeostatic processes as occurs with essential nutrients. Any complete Mn PBPK model would include the homeostatic regulation as an essential nutritional element and the additional exposure routes by inhalation. Two companion papers discuss the kinetic complexities of the quantitative dose-dependent alterations in hepatic and intestinal processes that control uptake and elimination of Mn (Teeguarden et al., 2006a, b). Radioactive 54Mn has been to investigate the behavior of the more common 55Mn isotope in the body because the distribution and elimination of tracer doses reflects the overall distributional characteristics of Mn. In this paper, we take the first steps in developing a multi-route PBPK model for Mn. Here we develop a PBPK model to account for tissue concentrations and tracer kinetics of Mn under normal dietary intake. This model for normal levels of Mn will serve as the starting point for more complete model descriptions that include dose-dependencies in both oral uptake and and biliary excretion. Material and Methods Experimental Data Two studies using 54Mn tracer were employed in model development. (Furchner et al. 1966; Wieczorek and Oberdorster 1989). In Furchner et al. (1966) male Sprague-Dawley rats received an ip injection of carrier-free 54MnCl2 while maintained on standard rodent feed containing ~ 45 ppm Mn. Tissue radioactivity of 54Mn was measured by liquid scintillation counting between post injection days 1 to 89 and reported as percent of administered dose per kg tissue. 54Mn time courses were reported for liver, kidney, bone, brain, muscle, blood, lung and whole body. Because ip uptake is via the portal circulation to the liver, this data set had information on distribution and clearance behaviors of Mn entering the systemic circulation from liver.
Determination of fluoxetine and norfluoxetine in plasma by gas chromatography with electron-capture detection
Nash, J.F.; Bopp, R.J.; Carmichael, R.H.; Farid, K.Z.; Lemberger, L.
This gas-chromatographic method for assay of fluoxetine and norfluoxetine in human plasma involves extraction of the drugs and use of a /sup 63/Ni electron-capture detector. The linear range of detection is 25 to 800 micrograms/L for each drug. Overall precision (CV) in the concentration range of 10 to 100 micrograms/L for both drugs was approximately 10%. Accuracy (relative error) in the same concentration range was approximately +10%. None of the commonly prescribed antidepressants or tranquilizers that we tested interfere with the assay.
Set-up of a new TDCR counter at IRA-METAS.
Nedjadi, Youcef; Bailat, Claude; Caffari, Yvan; Cassette, Philippe; Bochud, François
A triple-to-double coincidence ratio (TDCR) counter was recently constructed at IRA-METAS for liquid scintillation based primary activity standardisations. A description of its optical chamber, efficiency change tools, photomultiplier tubes (PMTs) and electronics is given. This TDCR system was validated by measuring several standard solutions of beta emitters including (45)Ca, (14)C, (63)Ni and (3)H. The activity concentrations, obtained from these measurements and efficiencies computed with a FORTRAN code we developed for symmetric and asymmetric PMTs, agree with the certified values within uncertainties. PMID:25569200
Optimization of Silicon parameters as a betavoltaic battery: Comparison of Si p-n and Ni/Si Schottky barrier
NASA Astrophysics Data System (ADS)
Rahmani, Faezeh; Khosravinia, Hossein
Theoretical studies on the optimization of Silicon (Si) parameters as the base of betavoltaic battery have been presented using Monte Carlo simulations and the state equations in semiconductor to obtain maximum power. Si with active area of 1 cm2 has been considered in p-n junction and Schottky barrier structure to collect the radiation induced-charge from 10 mCi cm-2 of Nickle-63 (63Ni) Source. The results show that the betavoltaic conversion efficiency in the Si p-n structure is about 2.7 times higher than that in the Ni/Si Schottky barrier structure.
Test of level density models from reactions of {sup 6}Li on {sup 58}Fe and {sup 7}Li on {sup 57}Fe
Oginni, B. M.; Grimes, S. M.; Voinov, A. V.; Adekola, A. S.; Brune, C. R.; Carter, D. E.; Heinen, Z.; Jacobs, D.; Massey, T. N.; O'Donnell, J. E.; Schiller, A.
The reactions of {sup 6}Li on {sup 58}Fe and {sup 7}Li on {sup 57}Fe have been studied at 15 MeV beam energy. These two reactions produce the same compound nucleus, {sup 64}Cu. The charged particle spectra were measured at backward angles. The data obtained have been compared with Hauser-Feshbach model calculations. The level density parameters of {sup 63}Ni and {sup 60}Co have been obtained from the particle evaporation spectra. We also find contributions from the break up of the lithium projectiles to the low energy region of the {alpha} spectra.
Prediction of betavoltaic battery output parameters based on SEM measurements and Monte Carlo simulation.
Yakimov, Eugene B
An approach for a prediction of (63)Ni-based betavoltaic battery output parameters is described. It consists of multilayer Monte Carlo simulation to obtain the depth dependence of excess carrier generation rate inside the semiconductor converter, a determination of collection probability based on the electron beam induced current measurements, a calculation of current induced in the semiconductor converter by beta-radiation, and SEM measurements of output parameters using the calculated induced current value. Such approach allows to predict the betavoltaic battery parameters and optimize the converter design for any real semiconductor structure and any thickness and specific activity of beta-radiation source. PMID:27017084
Improved methods of measurement and analysis of conversion electron and beta-particle spectra
Dragoun; Spalek; Rysavy; Kovalik; Yakushev; Brabec; Frana; Venos
A general statistical test of the stability of measurement conditions was demonstrated on the beta-spectra of 241Pu cumulated during four years. The alpha- and gamma-ray spectroscopy indicated stability of the 241Pu source. Monte Carlo modelling of individual collision events clarified the role of electron scattering and energy losses within a radioactive source down to energies of several hundreds of eV. The impact ionization by beta-particles of carbon and oxygen atoms in a surface contamination layer on the 241Pu and 63Ni sources was observed. PMID:10724379
Metal-organic frameworks derived CoxFe1-xP nanocubes for electrochemical hydrogen evolution
NASA Astrophysics Data System (ADS)
Hao, Jinhui; Yang, Wenshu; Zhang, Zhe; Tang, Jilin
Designing and developing active, cost-effective and stable electrocatalysts for hydrogen evolution reaction (HER) are still an ongoing challenge. Herein, we report the synthesis of binary transition metal phosphide (CoxFe1-xP) nanocubes with different Co and Fe ratios through a phosphidation process using metal-organic frameworks (MOFs) as templates. MOF templates contribute well-defined nanocube architectural features after phosphidation, while a suitable phosphidation temperature could allow formation of a crystal structure and maintain the well-defined structure. The incorporation of a binary transition metal results in redistribution of the valence electrons in CoxFe1-xP. The changes imply anionic states of the P and Fe atoms, which act as active sites and thus have stronger electron-donating ability. When CoxFe1-xP nanocubes are employed as electrocatalysts, these characteristic features facilitate the performance of HER. Remarkably, Co0.59Fe0.41P nanocubes prepared at 450 °C afford a current density of 10 mA cm-2 at a low overpotential of 72 mV in acidic conditions and 92 mV in alkaline conditions. Co0.59Fe0.41P nanocubes also exhibit a small Tafel slope of 52 mV decade-1 in acidic conditions and 72 mV decade-1 in alkaline conditions. Moreover, Co0.59Fe0.41P nanocubes show good stability in both acidic and alkaline conditions. Our method produces the highly active HER catalyst based on binary transition metal MOF templates, providing a new avenue for designing excellent electrocatalysts.Designing and developing active, cost-effective and stable electrocatalysts for hydrogen evolution reaction (HER) are still an ongoing challenge. Herein, we report the synthesis of binary transition metal phosphide (CoxFe1-xP) nanocubes with different Co and Fe ratios through a phosphidation process using metal-organic frameworks (MOFs) as templates. MOF templates contribute well-defined nanocube architectural features after phosphidation, while a suitable phosphidation
Effects of proteins on absorption by the rat of iron from polymeric and low-molecular-weight iron species
Berner, L.; Miller, D.
To examine effects of proteins on Fe absorption from polymeric ferric hydroxides (polys) or low-molecular-weight complexes (LMW Fe), 2 studies were conducted. First, anemic rats were given /sup 59/Fe-labeled polys or LMW Fe in the presence and absence of pepsin-digested soy protein isolate, casein, and BSA. The doses were introduced into ligated duodenal segments for 1 hr. Uptake into the carcass of /sup 59/Fe from polys was doubled in the presence of BSA (7.8 vs 16.1%, p < .05) while casein and soy had no effect (5.5 and 6.5%). Absorption of /sup 59/Fe from LMW Fe was 7X greater than from polys; BSA and casein had no effect but soy depressed Fe uptake by almost 50% (57.4 vs 35.5%, p < .05). The second experiment repeated the first except that the proteins were not pepsin-digested and the doses were given by gastric intubation. All Fe, whether from polys or LMW Fe, was highly available (although in vitro digestions reveal that polys are not depolymerized to a large degree under simulated stomach conditions). Soy depressed Fe uptake from both sources (92.9 vs. 81.6%, LMW Fe and 85.4 vs 73.7%, polys) while casein and BSA had no effect. These results show: (1) BSA can depolymerize polys in the rat duodenum, thus enhancing absorption; (2) soy isolate generally depressed Fe uptake; and (3) the rat stomach appears to have an exceptional capacity for equalizing Fe sources.
Correlation between erythropoietic activity and body growth rate in hypertransfused polycythemic growing rats as the result of an erythropoietin-dependent operating mechanism
Bozzini, C.E.; Alippi, R.M.; Barcelo, A.C.; Caro, J.
The established relationship between erythropoietic activity and body growth rate in the polycythemic growing rat could be the result of either an erythropoietin (EPO)-dependent or an EPO-independent operating mechanism. The present study was thus undertaken to elucidate the nature of the aforementioned mechanism by assessing the ratio between plasma immunoreactive EPO (iEPO) concentration and erythropoietic activity in young hypertransfused rats for different body growth rates. Red blood cell (RBC)-59Fe uptake was about 75% in 21-day-old rats; it rapidly decreased with time when the animals were placed on a protein-free diet, approaching a level of about 1% by the 10th day of protein starvation. Over the same period plasma iEPO decreased from 55 mU/ml to 7 mU/ml. Body growth rate was 0. Following this ''protein depletion period'' the rats received diets containing different amounts of casein (''protein repletion period'') added isocalorically to the protein-free diet to elicit a rise in body growth rate. Statistically significant relationships (p less than 0.001) were found between dietary casein concentration and body growth rate (r = 0.991), dietary casein concentration and RBC-59Fe uptake (r = 0.991), dietary casein concentration and plasma iEPO level (r = 0.992), body growth rate and RBC-59Fe (r = 0.986), and body growth rate and plasma iEPO level (r = 0.994) in hypertransfused polycythemic rats during the protein repletion period. These findings suggest that the correlation between erythropoietic activity and growth rate in the growing rat is the result of an erythropoietin-dependent operating mechanism, which appears to be independent of the ratio tissue oxygen supply/tissue oxygen demand.
Paramagnetic pyrophosphate. Preliminary studies on magnetic resonance contrast enhancement of acute myocardial infarction.
Maurer, A H; Knight, L C; Siegel, J A; Elfenbein, I B; Adler, L P
Ferric pyrophosphate (Fe-PyP) was investigated in an animal model of acute myocardial infarction for its potential to provide contrast enhancement of the peri-infarct zone using magnetic resonance (MR) imaging. Radiotracer studies compared the biodistribution of soluble 59Fe-PyP with 99mTc-PyP in excised tissue samples. Preferential localization of 59Fe-PyP in the peri-infarct zone was found to be similar to 99mTc-PyP. The ratio (percent dose/gram of tissue) at the edge of the infarct to normal tissue was 1.30 +/- 0.16 and 1.44 +/- 0.33 for 99mTc-PyP and 59Fe-PyP, respectively. In initial studies with high doses of the contrast agent, gated T1-weighted MR images of animals with 48-hour-old infarcts were obtained at 15-minute intervals after injection of Fe-PyP at a dose of 350 mg/kg. Contrast enhancement of the infarct zone was observed in all studies and was maximal 15-30 minutes after injection. Signal intensity ratios (infarct/normal) increased from a baseline 1.31 +/- 0.22 to a peak 1.90 +/- 0.57. Studies were then performed with smaller amounts of Fe-PyP. Images obtained with 50 mg/kg Fe-PyP showed contrast enhancement beginning at 60 minutes. Toxicology studies showed primarily respiratory effects, which became significant at doses of 190 mg/kg. These preliminary studies suggest that Fe-PyP potentially could serve as an MR contrast agent to localize and size acute myocardial infarcts; however, its clinical use may be limited by potential toxicity and dose limitations. PMID:2155882
Ferrous iron transport in Streptococcus mutans
Evans, S.L.; Arcenaeux, J.E.L.; Byers, B.R.; Martin, M.E.; Aranha, H.
Radioiron uptake from /sup 59/FeCl/sub 3/ by Streptococcus mutans OMZ176 was increased by anaerobiosis, sodium ascorbate, and phenazine methosulfate (PMS), although there was a 10-min lag before PMS stimulation was evident. The reductant ascorbate may have provided ferrous iron. The PMS was reduced by the cells, and the reduced PMS then may have generated ferrous iron for transport; reduced PMS also may have depleted dissolved oxygen. It was concluded that S. mutans transports only ferrous iron, utilizing reductants furnished by glucose metabolism to reduce iron prior to its uptake.
Failure to label baboon milk intrinsically with iron
Figueroa-Colon, R.; Elwell, J.H.; Jackson, E.; Osborne, J.W.; Fomon, S.J. )
The widely held belief that 50% of the iron in human milk is absorbed is based on studies that have used an extrinsic radioactive iron tag. To determine the validity of an extrinsic tag, it is necessary to label the milk intrinsically with one isotope and to compare absorption of this isotope with absorption of another isotope added as the extrinsic tag. We chose the baboon as a model and infused 59Fe intravenously. In each of three attempts we failed to label the milk intrinsically.
Studies on the mechanism of benzene toxicity.
Snyder, R; Dimitriadis, E; Guy, R; Hu, P; Cooper, K; Bauer, H; Witz, G; Goldstein, B D
Using the 59Fe uptake method of Lee et al. it was shown that erythropoiesis in female mice was inhibited following IP administration of benzene, hydroquinone, p-benzoquinone, and muconaldehyde. Toluene protected against the effects of benzene. Coadministration of phenol plus either hydroquinone or catechol resulted in greatly increased toxicity. The combination of metabolites most effective in reducing iron uptake was hydroquinone plus muconaldehyde. We have also shown that treating animals with benzene leads to the formation of adducts of bone marrow DNA as measured by the 32P-postlabeling technique. PMID:2792049
Dietary copper deficiency reduces iron absorption and duodenal enterocyte hephaestin protein in male and female rats.
Reeves, Philip G; Demars, Lana C S; Johnson, W Thomas; Lukaski, Henry C
The mechanism for reduced Fe absorption in Cu deficiency is unknown, but may involve the intestinal Cu-dependent ferroxidase, Hephaestin (Hp). A 2 x 2 factorial experiment was designed to include Cu-deficient (CuD) and Cu-adequate (CuA) male and female rats. Weanling rats of both sexes were randomly divided into 2 groups each and fed an AIN-93G diet with low (<0.3 mg/kg; CuD) or adequate Cu (5.0 mg/kg; CuA). After 19 d, rats were fed 1.0 g each of their respective diets labeled with (59)Fe. Retained (59)Fe was monitored by whole-body counting for 12 d. Then, rats were killed for (59)Fe and Fe measurements in blood and various organs. Duodenal enterocytes were isolated for Western blot analysis of Hp. Signs of Cu and Fe deficiency were evident in both sexes. CuD male rats absorbed 60% as much Fe as CuA male rats (P < 0.001), whereas CuD female rats absorbed 70% (P < 0.001) as much as CuA females, with no difference between the sexes. Hp protein in enterocytes of CuD rats of both sexes was only 35% of that in CuA rats. The biological half-life of (59)Fe in CuD rats was only 50% (P < 0.001) of that in CuA rats, suggesting that Fe turnover was faster in CuD rats than CuA rats. Serum, spleen, and kidney Fe were lower (P < 0.001) in CuD rats than in CuA rats. Duodenal mucosa and liver Fe were higher (P < 0.01) in CuD male rats than CuA rats. Duodenal Fe but not liver Fe was higher in CuD female rats than CuA rats. Liver Fe was much higher (<0.001) overall in females than males. The data suggest that Cu deficiency reduces Fe absorption in rats through reduced expression of duodenal Hp protein. PMID:15623839
Repletion of copper-deficient rats with dietary copper restores duodenal hephaestin protein and iron absorption.
Reeves, Philip G; Demars, Lana C S
Copper (Cu) deficiency in rats reduces the relative concentration of duodenal hephaestin (Hp), reduces iron (Fe) absorption, and causes anemia. An experiment was conducted to determine whether these effects could be reversed by dietary Cu repletion. Five groups of eight weanling male rats each were used. Group 1 was fed a Cu-adequate diet (5.0 mg Cu/kg; CuA) and Group 2 was fed a Cu-deficient diet (0.25 mg Cu/kg; CuD) for 28 days. The rats were fed 1.0 g each of their respective diets labeled with 59Fe (37 kBq/g), and the amount of label retained was measured one week later by whole-body-counting (WBC). Group 3 was fed a CuA diet and Groups 4 and 5 were fed a CuD diet for 28 days. Group 5 was then fed the CuA diet for another week while Groups 3 and 4 continued on their previous regimens. Rats in Groups 3, 4, and 5 were fed 1.0 g of diet labeled with 59Fe, and the amount of label retained was measured by WBC one week later. Rats were killed and duodenal enterocytes isolated for Hp protein analysis, whole blood was analyzed for hematological parameters, and various organs for 59Fe content. CuD rats absorbed less (P<0.05) Fe than CuA rats, the relative amount of duodenal Hp was less (P<0.05) in CuD rats, and the CuD rats developed anemia. After the CuD rats had been repleted with Cu for one week, Fe retention rose to values even higher (P<0.05) than those in CuA rats. After two weeks, the relative amount of duodenal Hp was higher (P<0.05) than normal, and most signs of anemia were reversed. Liver 59Fe was elevated in CuD rats, but was restored to normal upon Cu repletion. These findings suggest a strong association between duodenal Hp abundance and Fe absorption in the CuD rat, and that reduced Fe absorption is an important factor in the cause of anemia. PMID:15855298
Effects of PEG-Induced Water Deficit in Solanum nigrum on Zn and Ni Uptake and Translocation in Split Root Systems
Feller, Urs; Anders, Iwona; Wei, Shuhe
Drought strongly influences root activities in crop plants and weeds. This paper is focused on the performance of the heavy metal accumulator Solanum nigrum, a plant which might be helpful for phytoremediation. The water potential in a split root system was decreased by the addition of polyethylene glycol (PEG 6000). Rubidium, strontium and radionuclides of heavy metals were used as markers to investigate the uptake into roots, the release to the shoot via the xylem, and finally the basipetal transport via the phloem to unlabeled roots. The uptake into the roots (total contents in the plant) was for most makers more severely decreased than the transport to the shoot or the export from the shoot to the unlabeled roots via the phloem. Regardless of the water potential in the labeling solution, 63Ni and 65Zn were selectively redistributed within the plant. From autoradiographs, it became evident that 65Zn accumulated in root tips, in the apical shoot meristem and in axillary buds, while 63Ni accumulated in young expanded leaves and roots but not in the meristems. Since both radionuclides are mobile in the phloem and are, therefore, well redistributed within the plant, the unequal transfer to shoot and root apical meristems is most likely caused by differences in the cell-to-cell transport in differentiation zones without functional phloem (immature sieve tubes). PMID:27135329
Effects of PEG-Induced Water Deficit in Solanum nigrum on Zn and Ni Uptake and Translocation in Split Root Systems.
Feller, Urs; Anders, Iwona; Wei, Shuhe
Drought strongly influences root activities in crop plants and weeds. This paper is focused on the performance of the heavy metal accumulator Solanum nigrum, a plant which might be helpful for phytoremediation. The water potential in a split root system was decreased by the addition of polyethylene glycol (PEG 6000). Rubidium, strontium and radionuclides of heavy metals were used as markers to investigate the uptake into roots, the release to the shoot via the xylem, and finally the basipetal transport via the phloem to unlabeled roots. The uptake into the roots (total contents in the plant) was for most makers more severely decreased than the transport to the shoot or the export from the shoot to the unlabeled roots via the phloem. Regardless of the water potential in the labeling solution, (63)Ni and (65)Zn were selectively redistributed within the plant. From autoradiographs, it became evident that (65)Zn accumulated in root tips, in the apical shoot meristem and in axillary buds, while (63)Ni accumulated in young expanded leaves and roots but not in the meristems. Since both radionuclides are mobile in the phloem and are, therefore, well redistributed within the plant, the unequal transfer to shoot and root apical meristems is most likely caused by differences in the cell-to-cell transport in differentiation zones without functional phloem (immature sieve tubes). PMID:27135329
Roberts, M.L.; Bench, G.S.; Brown, T.A.
The AMS facility at Lawrence Livermore National Laboratory (LLNL) routinely measures the isotopes {sup 3}H, {sup 7}Be, {sup 10}Be, {sup 14}C, {sup 26}Al, {sup 36}Cl, {sup 41}Ca, {sup 59,63}Ni, and {sup 129}I. During the past two years, over 30,000 research samples have been measured. Of these samples, approximately 30% were for {sup 14}C bioscience tracer studies, 45% were {sup 14}C samples for archaeology and the geosciences, and the other isotopes constitute the remaining 25%. During the past two years at LLNL, a significant amount of work has gone into the development of the Projectile X-ray AMS (PXAMS) technique. PXAMS uses induced characteristic x-rays to discriminate against competing atomic isobars. PXAMS has been most fully developed for {sup 63}Ni but shows promise for the measurement of several other long lived isotopes. During the past year LLNL has also conducted an {sup 129}I interlaboratory comparison exercise. Recent hardware changes at the LLNL AMS facility include the installation and testing of a new thermal emission ion source, a new multianode gas ionization detector for general AMS use, re-alignment of the vacuum tank of the first of the two magnets that make up the high energy spectrometer, and a new cryo-vacuum system for the AMS ion source. In addition, they have begun design studies and carried out tests for a new high-resolution injector and a new beamline for heavy element AMS.
Organic complexant-enhanced mobility of toxic elements in low-level wastes. Annual report, July 1983-June 1984
Swanson, J.L.
This report describes the initial results obtained in a project whose objective is to determine how and to what extent organic complexants affect the mobility of toxic elements in subsurface groundwaters at commercial low-level waste disposal sites. Generic soil components (e.g., hydrous oxides, silica, clays) are being employed so that the results will be broadly applicable. Organic complexants used in the nuclear industry are being emphasized. Data have been obtained with two radioactive (/sup 63/Ni and /sup 239/Pu) and one nonradioactive toxic element (Cd). Work with /sup 63/Ni has been emphasized; it was studied with five different generic soil components (hydrous ferric oxide, silica, titania, kaolinite, and montmorillonite) and five different complexants (EDTA, NTA, picolinate, citrate, and oxalate). EDTA was the complexant studied most extensively and hydrous ferric oxide was the most studied soil component. A wide diversity of effects of organic complexants on toxic elements sorption was observed. The effects vary not only among complexants, but also among toxic elements and among soil components. In some systems the complexant results in increased toxic element sorption (decreased mobility) while in other systems the complexant results in decreased toxic element sorption (increased mobility). 16 references, 14 figures, 5 tables.
Organic complexant-enhanced mobility of toxic elements in low-level wastes
Swanson, J.L.
This paper describes the results obtained during the recent activities of a project whose objective is to determine how and to what extent organic complexants affect the mobility of toxic elements in subsurface groundwaters at commercial low-level waste disposal sites. Generic soil components (e.g., hydrous oxides, silica, clays) are being employed so that the results will be broadly applicable. Data have been obtained with two radionuclides (/sup 63/Ni and /sup 239/Pu) and one nonradioactive toxic element (Cd). Work with /sup 63/Ni has been emphasized; it was studied with five different generic soil components (hydrous ferric oxide, silica, titania, kaolinite, and montmorillonite) and five different complexants (EDTA, NTA, picolinate, citrate, and oxalate). EDTA was the complexant studied most extensively and hydrous ferric oxide, Fe/sub 2/O/sub 3/.xH/sub 2/O, was the most studied soil component. A wide diversity of effects of organic complexants on toxic elements sorption was observed. The effects vary not only among complexants, but also among toxic elements and among soil components. In some systems the complexant results in increased toxic element sorption (decreased mobility) while in other systems the complexant results in decreased toxic element sorption (increased mobility). 5 references, 5 figures, 2 tables.
Secondary ionization of chemical warfare agent simulants: atmospheric pressure ion mobility time-of-flight mass spectrometry.
Steiner, Wes E; Clowers, Brian H; Haigh, Paul E; Hill, Herbert H
For the first time, the use of a traditional ionization source for ion mobility spectrometry (radioactive nickel ((63)Ni) beta emission ionization) and three alternative ionization sources (electrospray ionization (ESI), secondary electrospray ionization (SESI), and electrical discharge (corona) ionization (CI)) were employed with an atmospheric pressure ion mobility orthogonal reflector time-of-flight mass spectrometer (IM(tof)MS) to detect chemical warfare agent (CWA) simulants from both aqueous- and gas-phase samples. For liquid-phase samples, ESI was used as the sample introduction and ionization method. For the secondary ionization (SESI, CI, and traditional (63)Ni ionization) of vapor-phase samples, two modes of sample volatilization (heated capillary and thermal desorption chamber) were investigated. Simulant reference materials, which closely mimic the characteristic chemical structures of CWA as defined and described by Schedule 1, 2, or 3 of the Chemical Warfare Convention treaty verification, were used in this study. A mixture of four G/V-type nerve simulants (dimethyl methylphosphonate, pinacolyl methylphosphonate, diethyl phosphoramidate, and 2-(butylamino)ethanethiol) and one S-type vesicant simulant (2-chloroethyl ethyl sulfide) were found in each case (sample ionization and introduction methods) to be clearly resolved using the IM(tof)MS method. In many cases, reduced mobility constants (K(o)) were determined for the first time. Ion mobility drift times, flight times, relative signal intensities, and fragmentation product signatures for each of the CWA simulants are reported for each of the methods investigated. PMID:14615983
Investigation of the generation of several long-lived radionuclides of importance in fusion reactor technology: Report on a Coordinated Research Program sponsored by the International Atomic Energy Agency
Smith, D.L.; Pashchenko, A.B.
The IAEA initiated a Coordinated Research Program (CRP) in 1988 to obtain reliable information for 16 long-lived activation reactions of special importance to fusion reactor technology: {sup 27}Al (n, 2n){sup 26}Al, {sup 63}Cu(n,p){sup 63}Ni, {sup 94}Mo(n,p) {sup 94}Nb, {sup 109}Ag(n,2n){sup 108m}Ag, {sup 179}Hf(n,2n) {sup 178m2}Hf, {sup 182}W(n,n{sup `}a){sup 178m2}Hf, {sup 151}Eu(n,2n) {sup 150}gEu, {sup 153}Eu(n,2n){sup 152+m2}Eu, {sup 159}Tb(n, 2n){sup 158}Tb, {sup 158}Dy(n,p){sup 158}Tb, {sup 193}Ir(n,2n) {sup 192m2}Ir, {sup 187}Re(n,2n){sup 186m}Re, {sup 62}Ni(n{gamma}) {sup 63}Ni, {sup 98}Mo(n,{gamma}){sup 99}Mo({beta}-){sup 99}Tc, {sup 165}Ho(n,{gamma}) {sup 166m}Ho and {sup 191}Ir(n,{gamma}){sup 192m2}Ir. this paper documents progress achieved from the start of the program through mid- 1993.
Low-temperature plasma ionization differential ion mobility spectrometry.
Kuklya, Andriy; Engelhard, Carsten; Uteschil, Florian; Kerpen, Klaus; Marks, Robert; Telgheder, Ursula
A low-temperature plasma (LTP) was used as an ionization source for differential ion mobility spectrometry (DMS) for the first time. This ionization source enhances the potential of DMS as a miniaturized system for on-site rapid monitoring. The effects of experimental parameters (e.g., discharge/carrier gas composition and flow rate, applied voltage) on the analysis of model aromatic compounds were investigated and discussed. It was found that the nature of reactant ion positive (RIP) is dependent on the discharge/carrier gas composition. The best response to the analyte was achieved when pure nitrogen was used as the discharge/carrier gas. The ability to perform analysis with zero helium consumption is especially attractive in view of the potential application of LTP-DMS for online (and on-site) monitoring. Analytical performance was determined with six environmentally relevant model compounds (benzene, toluene, ethylbenzene, p-xylene, 1,2,4-trimethylbenzene, and naphthalene) using LTP and directly compared to APPI and APCI ((63)Ni) ionization sources. When LTP was coupled to DMS, calculated LOD values were found to be in the range of 35-257 ng L(-1) (concentration in the carrier gas). These values are competitive with those calculated for two DMS equipped with traditional ionization sources (APPI, (63)Ni). The obtained results are promising enough to ensure the potential of LTP as ionization source for DMS. PMID:26266836
Bioaccumulation of nickel by algae
Wang, H.K.; Wood, J.M.
Six strains of algae and one Euglena sp. were tested for their ability to bioaccumulate nickel. Radioactive /sup 63/Ni was used together with a microplate technique to determine the conditions for nickel removal by axenic cultures of cyanobacteria, green algae, and one euglenoid. The cyanobacteria tested were found to be more sensitive to nickel toxicity than the green algae or the Euglena sp. The concentration factor (CF) for nickel was determined under a variety of conditions and found to be in the range from 0 to 3.0 x 10/sup 3/. The effect of environmental variables on nickel uptake was examined, and a striking pH effect for biaccumulation was observed, with most of the algal strains accumulating nickel optimally at approximately pH 8.0. Competition experiments for binding sites between nickel and other cations as well as with other complexing anions, showed that /sup 63/Ni uptake was affected only by cobalt and by humic acids.
The liver cell plasma membrane Ca2+ inflow systems exhibit a broad specificity for divalent metal ions.
Crofts, J N; Barritt, G J
1. The inflow of Mn2+ across the plasma membranes of isolated hepatocytes was monitored by measuring the quenching of the fluorescence of intracellular quin2, by atomic absorption spectroscopy and by the uptake of 54Mn2+. The inflow of other divalent metal ions was measured using quin2. 2. Under ionic conditions which resembled those present in the cytoplasmic space, Mn2+, Zn2+, Co2+, Ni2+ and Cd2+ each quenched the fluorescence of a solution of Ca2(+)-quin2. 3. The addition of Mn2+, Zn2+, Co2+, Ni2+ or Cd2+ to cells loaded with quin2 caused a time-dependent decrease in the fluorescence of intracellular quin2. Plots of the rate of decrease in fluorescence as a function of the concentration of Mn2+ reached a plateau at 100 microM-Mn2+. 4. The rate of decrease in fluorescence induced by Mn2+ was stimulated by 20% in the presence of vasopressin. The effect of vasopressin was completely inhibited by 200 microM-verapamil. Adrenaline, angiotensin II and glucagon also stimulated the rate of decrease in the fluorescence of intracellular quin2 induced by Mn2+. 5. The rate of decrease in fluorescence induced by Zn2+, Co2+, Ni2+ or Cd2+ was stimulated by between 20 and 190% in the presence of vasopressin or angiotensin II. 6. The rates of uptake of Mn2+ measured by atomic absorption spectroscopy or by using 54Mn2+ were inhibited by about 20% by 1.3 mM-Ca2+o and stimulated by 30% by vasopressin. 7. Plots of Mn2+ uptake, measured by atomic absorption spectroscopy or with 54Mn2+, as a function of the extracellular concentration of Mn2+ were biphasic over the range 0.05-1.0 mM added Mn2+ and did not reach a plateau at 1.0 mM-Mn2+. 8. It is concluded that (i) hepatocytes possess both a basal and a receptor-activated divalent cation inflow system, each of which has a broad specificity for metal ions, and (ii) the receptor-activated divalent cation inflow system is the receptor-operated Ca2+ channel. PMID:2167660
Effects of ocean acidification on trace element accumulation in the early-life stages of squid Loligo vulgaris.
Lacoue-Labarthe, T; Réveillac, E; Oberhänsli, F; Teyssié, J L; Jeffree, R; Gattuso, J P
The anthropogenic release of carbon dioxide (CO(2)) into the atmosphere leads to an increase in the CO(2) partial pressure (pCO(2)) in the ocean, which may reach 950 μatm by the end of the 21st century. The resulting hypercapnia (high pCO(2)) and decreasing pH ("ocean acidification") are expected to have appreciable effects on water-breathing organisms, especially on their early-life stages. For organisms like squid that lay their eggs in coastal areas where the embryo and then paralarva are also exposed to metal contamination, there is a need for information on how ocean acidification may influence trace element bioaccumulation during their development. In this study, we investigated the effects of enhanced levels of pCO(2) (380, 850 and 1500 μatm corresponding to pH(T) of 8.1, 7.85 and 7.60) on the accumulation of dissolved (110m)Ag, (109)Cd, (57)Co, (203)Hg, (54)Mn and (65)Zn radiotracers in the whole egg strand and in the different compartments of the egg of Loligo vulgaris during the embryonic development and also in hatchlings during their first days of paralarval life. Retention properties of the eggshell for (110m)Ag, (203)Hg and (65)Zn were affected by the pCO(2) treatments. In the embryo, increasing seawater pCO(2) enhanced the uptake of both (110m)Ag and (65)Zn while (203)Hg showed a minimum concentration factor (CF) at the intermediate pCO(2). (65)Zn incorporation in statoliths also increased with increasing pCO(2). Conversely, uptake of (109)Cd and (54)Mn in the embryo decreased as a function of increasing pCO(2). Only the accumulation of (57)Co in embryos was not affected by increasing pCO(2). In paralarvae, the CF of (110m)Ag increased with increasing pCO(2), whereas the (57)Co CF was reduced at the highest pCO(2) and (203)Hg showed a maximal uptake rate at the intermediate pCO(2). (54)Mn and (65)Zn accumulation in paralarvae were not significantly modified by hypercapnic conditions. Our results suggest a combined effect of pH on the adsorption and
Deposition of fission and activation products after the Fukushima Dai-ichi nuclear power plant accident.
Shozugawa, Katsumi; Nogawa, Norio; Matsuo, Motoyuki
The Great Eastern Japan Earthquake on March 11, 2011, damaged reactor cooling systems at Fukushima Dai-ichi nuclear power plant. The subsequent venting operation and hydrogen explosion resulted in a large radioactive nuclide emission from reactor containers into the environment. Here, we collected environmental samples such as soil, plant species, and water on April 10, 2011, in front of the power plant main gate as well as 35 km away in Iitate village, and observed gamma-rays with a Ge(Li) semiconductor detector. We observed activation products ((239)Np and (59)Fe) and fission products ((131)I, (134)Cs ((133)Cs), (137)Cs, (110m)Ag ((109)Ag), (132)Te, (132)I, (140)Ba, (140)La, (91)Sr, (91)Y, (95)Zr, and (95)Nb). (239)Np is the parent nuclide of (239)Pu; (59)Fe are presumably activation products of (58)Fe obtained by corrosion of cooling pipes. The results show that these activation and fission products, diffused within a month of the accident. PMID:22266366
Isolation of an iron-binding protein from the hemolymph of the horseshoe crab (Limulus polyhemus)
Topham, R.; Cooper, B.; Tesh, S.; Bonaventura, C.
The presence of an iron-binding protein in the hemolymph of Limulus was detected by gel-filtration of /sup 59/Fe-labeled hemolymph. This protein was easily separated from hemocyanin, the oxygen transport protein that constitutes greater than 90% of the protein of Limulus hemolymph. The amount of the Limulus iron-binding protein (LIBP) in hemolymph samples prepared under sterile and non-sterile conditions was identical. LIBP was purified to homogeneity by ion-exchange chromatography. The molecular weight of purified LIBP was estimated by gel-filtration to be 282,000 + 10,000. SDS-electrophoresis demonstrated that LIBP was an oligomeric protein composed of subunits with a molecular weight of 28,000 +/- 2000. The isoelectric point of LIBP was 6.5 as determined by electrofocusing. No /sup 49/Fe was removed from purified LIBP by extensive dialysis with EDTA or 2,2'-dipyridyl. Purified, unlabeled LIBP efficiently sequestered /sup 59/Fe in the absence of hemolymph indicating that no other hemolymph factors are required for the incorporation of iron into LIBP. The isolation of LIBP would support the proposal that the development of specific iron-binding and transport proteins was not necessarily coupled to the development of hemoglobin as a means to accomplish oxygen transport.
Iron fortification of flour with a complex ferric orthophosphate
Hallberg, L.; Rossander-Hulthen, L.; Gramatkovski, E.
The unexpectedly low bioavailability in humans of elemental iron powder prompted us to search for other Fe compounds suitable for Fe fortification of flour that fulfill the two requirements of insolubility in water (due to high water content of flour) and good bioavailability in humans. Systematic studies of compatibility, solubility, and bioavailability led to this study of a microcrystalline complex ferric orthophosphate (CFOP), Fe/sub 3/H/sub 8/(NH/sub 4/)-(PO/sub 4/)6.6H/sub 2/O, a well-defined compound. This compound was labeled with /sup 59/Fe, and the native Fe in meals was labeled with /sup 55/FeCl3. The ratio of absorbed /sup 59/Fe to absorbed /sup 55/Fe is a direct measure of the fraction of CFOP that joins the nonheme Fe pool and that is made potentially available for absorption. The relative bioavailability of CFOP varied from 30% to 60% when labeled wheat rolls were served with different meals. The CFOP meets practical requirements of an Fe fortificant for flour well, with regard to both compatibility and bioavailability in humans.
Lung clearance of neutron-activated Mount St. Helens volcanic ash in the rat.
Wehner, A P; Wilerson, C L; Stevens, D L
To determine pulmonary deposition and clearance of inhaled volcanic ash, rats received a single 60-min, nose-only exposure to neutron-activated ash. Over a period of 128 days after exposure, the rats were sacrificed in groups of five animals. Lungs were analyzed for the radionuclide tracers 46Sc, 59Fe, and 60Co by gamma-ray spectrometry. The alveolar ash burdens, determined by the radionuclides 46Sc and 59Fe, are in good agreement for the majority of samples analyzed, indicating ash particulate levels in the lungs, rather than leached radionuclides. The ash deposition estimates based on 60Co were appreciably lower for the lungs, indicating that 60Co leached from the ash. Approximately 110 micrograms ash, or 6% of the inhaled ash, was initially retained in the deep lung. The biological half-time of the alveolar ash burden was 39 days. After 90 days, the mean lung burden had decreased to about 20% of its initial value; 128 days after exposure, about 10% remained. PMID:6489290
Lund clearance of neutron-activated Mount St. Helens volanic ash in the rat
Wehner, A.P.; Wilerson, C.L.; Stevens, D.L.
To determine pulmonary deposition and clearance of inhaled volcanic ash, rats received a single 60-min, nose-only exposure to neutron-activated ash. Over a period of 128 days after exposure, the rats were sacrificed in groups of five animals. Lungs were analyzed for the radionuclide tracers /sup 46/Sc, /sup 59/Fe, and /sup 60/Co by ..gamma..-ray spectrometry. The alveolar ash burdens, detemined by the radionuclides /sup 46/Sc and /sup 59/Fe, are in good agreement for the majority of samples analyzed, indicating ash particulate levels in the lungs, rather than leached radionuclides. The ash deposition estimates based on /sup 60/Co were appreciably lower for the lungs, indicating that /sup 60/Co leached from the ash. Approximately 110 ..mu..g ash, or 6% of the inhaled ash, was initially retained in the deep lung. The biological half-time of the alveolar ash burden was 39 days. After 90 days, the mean lung burden had decreased to about 20% of its initial value; 128 days after exposure, about 10% remained.
Small vessel hematocrit in ischemic myocardium
Gumm, D.C.; Cooper, S.M.; Marcus, M.L.; Chilian, W.M.; Harrison, D.G.
As blood enters the microvasculature of normally perfused myocardium, there is a progressive decrease in small vessel hematocrit (SV Hct) due to RBC streaming in smaller branching vessels and the Fahraeus-Lindqvist effect. We hypothesized that if the coronary collateral circulation was composed of very small vessels branching from large parent vessels, plasma streaming would result in a further decrease of SV Hct in ischemic myocardium. Six open chest anesthetized dogs were studied. Plasma was labelled with /sup 59/FeCl siderophilin and RBC's with /sup 99/mTc to estimate SV Hct from myocardial biopsies. The LAD was occluded and cannulated for measurement of retrograde flow (arising presumably from proximal collaterals). The ischemic region was identified using the microsphere shadow technique. Collateral flow after LAD occlusion was 30 +- 12 ml/min 100g (x +- SE). Systemic Hct was 40 +- 1%. The Hct of blood from retrograde flow was 39 +- 1% (p = NS). Activity of /sup 59/FeCl and /sup 99/mTc in known quantities of blood were compared to myocardial biopsies to estimate SV Hct. Ischemic SV Hct was 23 +- 2% and non-ischemic SV Hct was 21 +- 1% (p = NS). We conclude that the size and branching pattern of coronary collaterals is such that plasma streaming in collaterals does not result in an additional decrease in SV Hct in ischemic myocardium.
The characteristic assessment of spent ion exchange resin from PUSPATI TRIGA REACTOR (RTP) for immobilization process
Wahida, Nurul; Yasir, Muhamad Samudi; Majid, Amran Ab; Irwan, M. N.; Wahab, Mohd Abd; Marzukee, Nik; Paulus, Wilfred; Phillip, Esther; Thanaletchumy
In this paper, spent ion exchange resin generated from PUSPATI TRIGA reactor (RTP) in Malaysian Nuclear Agency were characterized based on the water content, radionuclide content and radionuclide leachability. The result revealed that the water content in the spent resin is 48%. Gamma spectrometry analysis indicated the presence of {sup 134}Cs, {sup 137}Cs, {sup 152}Eu, {sup 54}Mn, {sup 58}Co, {sup 60}Co and {sup 65}Zn. The leachability test shows a small concentrations (<1 Bq/l) of {sup 152}Eu and {sup 134}Cs were leached out from the spent resin while {sup 60}Co activity concentrations slightly exceeded the limit generally used for industrial wastewater i.e. 1 Bq/l. Characterization of spent ion exchange resin sampled from RTP show that this characterization is important as a basis to immobilize this radioactive waste using geopolymer technology.
A low-level activation technique for monitoring thermonuclear fusion plasma conditions.
Gasparro, Joël; Hult, Mikael; Bonheure, Georges; Johnston, Peter N
Optimisation of the confinement and sustainability of a thermonuclear plasma requires methods to monitor processes in the plasma. In this work three materials were used as activation targets (Ti, MgF2 and a TiVAl compound). They were placed inside the joint European Torus (JET) vacuum chamber. Certain gamma-ray emitting radionuclides (7Be, 54Mn, 56Co, 57Co, 58Co and 46Sc) were measured using ultra low-level gamma-ray spectrometry in an underground laboratory 1-2 months after activation. They were found to arise from neutron activation of bulk sample material and surface contaminants sputtered from other Tokamak parts. Decision thresholds for some activation products were determined in order to aid in giving upper bounds for the flux of charged particles. PMID:16580838
Comparison of attenuation correction methods for TGS and SGS: Do we really need selenium-75?
Estep, R.J.; Prettyman, T.H.; Sheppard, G.A.
We compared attenuation-coefficient mapping techniques for use in tomographic gamma scanner (TGS) image reconstructions to determine whether there is a significant improvement when using fully coupled methods. For the constrained least-squares image reconstruction method tested here, we found no significant improvement. We also compared the effectiveness of different transmission source combinations for 129- and 414-keV {sup 239}Pu TGS assays. We concluded that the best source combination for TGS assays of {sup 239}Pu and other isotopes is a mixture of {sup 133}Ba, {sup 54}Mn, and {sup 60}Co. Three other source combinations were found to be at least as effective as {sup 75}Se.
Recoil range distributions of residues from. cap alpha. + /sup 59/Co reactions
Gadioli, E.; Gadioli Erba, E.; Parker, D.J.; Asher, J.
The recoil range distributions of /sup 61/Cu, /sup 60/Cu, /sup 58/Co, /sup 57/Co, /sup 56/Co, /sup 54/Mn, and /sup 52/Mn residual nuclei produced in ..cap alpha.. particle bombardment of /sup 59/Co at 38, 50, 65, and 85 MeV have been measured and analyzed. Analysis of these measurements, as well as other recently published measurements of longitudinal linear momentum transfer to residue isobars at energies extending up to roughly-equal200 MeV, in the same reaction, shows that calculations based on the exciton model and a realistic description of the ..cap alpha..-nucleus interaction allow a quantitatively correct description of ..cap alpha..-induced reactions. Contrary to recent suggestions, data of this kind do not seem to indicate a change in the general character of the ..cap alpha..-nucleus interaction for incident energies below roughly-equal50 MeV/nucleon.
Changes to Irradiation Conditions of VVER-1000 Surveillance Specimens Resulting from Fuel Assemblies with Greater Fuel Height
NASA Astrophysics Data System (ADS)
Panferov, Pavel; Kochkin, Viacheslav; Erak, Dmitry; Makhotin, Denis; Reshetnikov, Alexandr; Timofeev, Andrey
The goal of the work was to obtain experimental data on the influence of newtype fuel assemblies with higher fuel rods on the irradiation conditions of surveillance specimens installed on the baffe of VVER-1000. For this purpose, two surveillance sets with container assemblies of the same design irradiated in reactors with different fuel assemblies in the core were investigated. Measurements of neutron dosimeters from these sets and retrospective measurements of 54Mn activity accumulated in each irradiated specimen allow a detailed distribution of the fast neutron flux in the containers to be obtained. Neutron calculations have been done using 3D discrete ordinate code KATRIN. On the basis of the obtained results, a change of the lead factor due to newtype fuel assemblies was evaluated for all types of VVER-1000 container assemblies.
Elemental compositions and ages of lunar samples by nondestructive gamma-ray spectrometry.
O'kelley, G D; Eldridge, J S; Schonfeld, E; Bell, P R
A gamma-ray spectrometry system with low background was used to determine the radioactivity of crystalline rocks, breccias, and fine material. Nuclides identified were (40)K, (232)Th, (238)U, (7)Be, (22)Na (26)A1, (44)Ti, (46)Sc, (48)V, (52)Mn, (54)Mn, and (56)Co. Concentrations of K, Th, and U ranged between 480 and 2550, 1.01 and 3.30, and 0.26 and 0.83 parts per million, respectively. Concentrations of thorium and uranium were those of terrestrial basalts, while the potassium concentrations were near values for chondrites. Products of low-energy nuclear reactions showed pronounced concentration gradients at rock surfaces. Concentrations of K and of (22)Na determined here were combined with concentrations of rare gases to estimate gas-retention ages and cosmic-ray exposure ages with ranges of 2200 to 3200 and 34 to 340 million years, respectively, for three rocks. PMID:17781504
Evaluation of induced radioactivity in structural material of Toshiba Training Reactor 'TTR1'.
Uematsu, Mikio; Kurosawa, Masahiko; Haruguchi, Yoshiko
A decommissioning programme for the Toshiba Training Reactor (TTR1), a swimming pool type reactor used for reactor physics experiments and material irradiation, was started in August 2001. As a part of the programme, induced radioactivity in structural material was evaluated using neutron flux data obtained with the three-dimensional Sn code TORT. Induced activity was calculated with the isotope generation code ORIGEN-79 using activation cross section data created from multi-group library based on JENDL-3. The obtained results for radioactivities such as 60Co, 65Zn, 54Mn and 152Eu were compared with measured ones, and the present calculational method was confirmed to have enough accuracy. PMID:16604643
Level density and mechanism of deuteron-induced reactions on 54,58,56Fe
NASA Astrophysics Data System (ADS)
Ramirez, A. P. D.; Voinov, A. V.; Grimes, S. M.; Byun, Y.; Brune, C. R.; Massey, T. N.; Akhtar, S.; Dhakal, S.; Parker, C. E.
Deuteron elastic cross sections, as well as neutron, proton, and α -particle emission spectra, from d + 54,58,56Fe reactions have been measured with deuteron beam energies of 5, 7, and 9 MeV. Optical model parameters have been tested against our experimental data. The fraction of total reaction cross section responsible for the formation of compound nuclei has been deduced from the angular distributions. The degree of discrepancy between calculated and experimental compound cross sections was found to increase with increasing neutron number. The nuclear level densities of the residual nuclei 57Co, 55Co, 57Fe, 55Fe, 52Mn, 54Mn have been deduced from the compound double differential cross sections. The Gilbert-Cameron model with Iljinov parameter systematics [A. S. Iljinov and M. V. Mebel, Nucl. Phys. A 543, 517 (1992)], 10.1016/0375-9474(92)90278-R was found to have a good agreement with our results.
Level density and mechanism of deuteron-induced reactions on Fe54,56,58
Ramirez, A. P. D.; Voinov, A. V.; Grimes, S. M.; Byun, Y.; Brune, C. R.; Massey, T. N.; Akhtar, S.; Dhakal, S.; Parker, C. E.
Here, deuteron elastic cross sections, as well as neutron, proton, and α-particle emission spectra, from d+54,56,58Fe reactions have been measured with deuteron beam energies of 5, 7, and 9 MeV. Optical model parameters have been tested against our experimental data. The fraction of total reaction cross section responsible for the formation of compound nuclei has been deduced from the angular distributions. The degree of discrepancy between calculated and experimental compound cross sections was found to increase with increasing neutron number. The nuclear level densities of the residual nuclei 55Co, 57Co, 55Fe, 57Fe, 52Mn, and 54Mn have been deduced from themore » compound double differential cross sections. The Gilbert-Cameron model with Iljinov parameter systematics [A. S. Iljinov and M. V. Mebel, Nucl. Phys. A 543, 517 (1992)] was found to have a good agreement with our results.« less
Evaluation of radiological data of some saturated fatty acids using gamma ray spectrometry
NASA Astrophysics Data System (ADS)
Kore, Prashant S.; Pawar, Pravina P.; Palani Selvam, T.
Radiological parameters such as mass attenuation coefficients (μm), total attenuation cross section (σtot), molar extinction coefficient (ε), mass energy absorption coefficient (μen/ρ) and effective electronic cross section (σt, el) of saturated fatty acids, namely butyric acid (C4H8O2), caproic acid (C6H12O2), enanthic acid (C7H14O2), caprylic acid (C8H16O2), pelargonic acid (C9H18O2) and valeric acid (C5H10O2) were measured using NaI(Tl)-based gamma spectrometry. Radioactive sources used in the study are 57Co, 133Ba, 137Cs, 54Mn, 60Co and 22Na. Gamma ray transmission method in a narrow beam good geometry set up was used in the study. The measured data were compared against Win-XCOM-based data. The agreement is within 1%.
The characteristic assessment of spent ion exchange resin from PUSPATI TRIGA REACTOR (RTP) for immobilization process
NASA Astrophysics Data System (ADS)
Wahida, Nurul; Yasir, Muhamad Samudi; Majid, Amran Ab; Wahab, Mohd Abd; Marzukee, Nik; Paulus, Wilfred; Phillip, Esther; Thanaletchumy, Irwan, M. N.
In this paper, spent ion exchange resin generated from PUSPATI TRIGA reactor (RTP) in Malaysian Nuclear Agency were characterized based on the water content, radionuclide content and radionuclide leachability. The result revealed that the water content in the spent resin is 48%. Gamma spectrometry analysis indicated the presence of 134Cs, 137Cs, 152Eu, 54Mn, 58Co, 60Co and 65Zn. The leachability test shows a small concentrations (<1 Bq/l) of 152Eu and 134Cs were leached out from the spent resin while 60Co activity concentrations slightly exceeded the limit generally used for industrial wastewater i.e. 1 Bq/l. Characterization of spent ion exchange resin sampled from RTP show that this characterization is important as a basis to immobilize this radioactive waste using geopolymer technology.
Manganese transport in Brevibacterium ammoniagenes ATCC 6872.
Schmid, J; Auling, G
Uptake of manganese by Brevibacterium ammoniagenes ATCC 6872 was energy dependent and obeyed saturation kinetics (Km = 0.65 microM; Vmax = 0.12 mumol/min per g [dry weight]). Uptake showed optima at 27 degrees C and pH 9.5. 54Mn2+ accumulated by the cells was released by treatment with toluene or by exchange for unlabeled manganese ions, via an energy-dependent process. Co2+, Fe2+, Cd2+, and Zn2+ inhibited manganese uptake. Inhibition by Cd2+ and Zn2+ was competitive (Ki = 0.15 microM Cd2+ and 1.2 microM Zn2+). Experiments with 65Zn2+ provided no evidence for Zn2+ uptake via the Mn2+ transport system. PMID:3597325
Visualization of Uptake of Mineral Elements and the Dynamics of Photosynthates in Arabidopsis by a Newly Developed Real-Time Radioisotope Imaging System (RRIS).
Sugita, Ryohei; Kobayashi, Natsuko I; Hirose, Atsushi; Saito, Takayuki; Iwata, Ren; Tanoi, Keitaro; Nakanishi, Tomoko M
Minerals and photosynthates are essential for many plant processes, but their imaging in live plants is difficult. We have developed a method for their live imaging in Arabidopsis using a real-time radioisotope imaging system. When each radioisotope,(22)Na,(28)Mg,(32)P-phosphate,(35)S-sulfate,(42)K,(45)Ca,(54)Mn and(137)Cs, was employed as an ion tracer, ion movement from root to shoot over 24 h was clearly observed. The movements of(22)Na,(42)K,(32)P,(35)S and(137)Cs were fast so that they spread to the tip of stems. In contrast, high accumulation of(28)Mg,(45)Ca and(54)Mn was found in the basal part of the main stem. Based on this time-course analysis, the velocity of ion movement in the main stem was calculated, and found to be fastest for S and K among the ions we tested in this study. Furthermore, application of a heat-girdling treatment allowed determination of individual ion movement via xylem flow alone, excluding phloem flow, within the main stem of 43-day-old Arabidopsis inflorescences. We also successfully developed a new system for visualizing photosynthates using labeled carbon dioxide,(14)CO2 Using this system, the switching of source/sink organs and phloem flow direction could be monitored in parts of whole shoots and over time. In roots,(14)C photosynthates accumulated intensively in the growing root tip area, 200-800 µm behind the meristem. These results show that this real-time radioisotope imaging system allows visualization of many nuclides over a long time-course and thus constitutes a powerful tool for the analysis of various physiological phenomena. PMID:27016100
Leach tests on grouts made with actual and trace metal-spiked synthetic phosphate/sulfate waste
Serne, R.J.; Martin, W.J.; LeGore, V.L.; Lindenmeier, C.W.; McLaurine, S.B.; Martin, P.F.C.; Lokken, R.O.
Pacific Northwest Laboratory conducted experiments to produce empirical leach rate data for phosphate-sulfate waste (PSW) grout. Effective diffusivities were measured for various radionuclides ({sup 90}Sr, {sup 99}Tc, {sup 14}C, {sup 129}I, {sup 137}Cs, {sup 60}Co, {sup 54}Mn, and U), stable major components (NO{sub 3}{sup {minus}}, SO{sub 4}{sup 2{minus}}, H{sub 3}BO{sub 3}, K and Na) and the trace constituents Ag, As, Cd, Hg, Pb, and Se. Two types of leach tests were used on samples of actual PSW grout and synthetic PSW grout: the American Nuclear Society (ANS) 16.1 intermittent replacement leach test and a static leach test. Grout produced from both synthetic and real PSW showed low leach rates for the trace metal constituents and most of the waste radionuclides. Many of the spiked trace metals and radionuclides were not detected in any leachates. None of the effluents contained measurable quantities of {sup 137}Cs, {sup 60}Co, {sup 54}Mn, {sup 109}Cd, {sup 51}Cr, {sup 210}Pb, {sup 203}Hg, or As. For those trace species with detectable leach rates, {sup 125}I appeared to have the greatest leach rate, followed by {sup 99}Tc, {sup 75}Se, and finally U, {sup 14}C, and {sup 110m}Ag. Leach rates for nitrate are between those for I and Tc, but there is much scatter in the nitrate data because of the very low nitrate inventory. 32 refs., 6 figs., 15 tabs.
Visualization of Uptake of Mineral Elements and the Dynamics of Photosynthates in Arabidopsis by a Newly Developed Real-Time Radioisotope Imaging System (RRIS)
Sugita, Ryohei; Kobayashi, Natsuko I.; Hirose, Atsushi; Saito, Takayuki; Iwata, Ren; Tanoi, Keitaro; Nakanishi, Tomoko M.
Minerals and photosynthates are essential for many plant processes, but their imaging in live plants is difficult. We have developed a method for their live imaging in Arabidopsis using a real-time radioisotope imaging system. When each radioisotope, 22Na, 28Mg, 32P-phosphate, 35S-sulfate, 42K, 45Ca, 54Mn and 137Cs, was employed as an ion tracer, ion movement from root to shoot over 24 h was clearly observed. The movements of 22Na, 42K, 32P, 35S and 137Cs were fast so that they spread to the tip of stems. In contrast, high accumulation of 28Mg, 45Ca and 54Mn was found in the basal part of the main stem. Based on this time-course analysis, the velocity of ion movement in the main stem was calculated, and found to be fastest for S and K among the ions we tested in this study. Furthermore, application of a heat-girdling treatment allowed determination of individual ion movement via xylem flow alone, excluding phloem flow, within the main stem of 43-day-old Arabidopsis inflorescences. We also successfully developed a new system for visualizing photosynthates using labeled carbon dioxide, 14CO2. Using this system, the switching of source/sink organs and phloem flow direction could be monitored in parts of whole shoots and over time. In roots, 14C photosynthates accumulated intensively in the growing root tip area, 200–800 µm behind the meristem. These results show that this real-time radioisotope imaging system allows visualization of many nuclides over a long time-course and thus constitutes a powerful tool for the analysis of various physiological phenomena. PMID:27016100
Lysimeter study of commercial reactor waste forms: waste form acquisition characterization and full-scale leaching
Not Available
This report describes work conducted at Brookhaven National Laboratory (BNL) as part of a joint program with Savannah River Laboratory. Typical full-scale (55-gallon drum size) waste forms were acquired by BNL from a boiling water reactor (BWR) and a pressurized water reactor (PWR). Liquid waste stream activity concentrations were analyzed by gamma spectroscopy. This information was used to determine the waste from activity inventory, providing the necessary source term for lysimeter and leaching experiments. Predominant radionuclides of interest include /sup 60/Co, /sup 137/Cs, /sup 134/Cs, and /sup 54/Mn. A full-scale leaching experiment was initiated by BNL encompassing four representative waste stream-solidification agent combinations. Waste streams tested include PWR evaporator concentrate (boric acid waste), BWR evaporator concentrate (sodium sulfate waste) and BWR evaporator concentrate plus ion exchange resins. Solidification agents include masonry cement, portland type III cement, and vinyl ester-styrene (Dow polymer). Analyses of leachates indicate measurable leach rates of /sup 137/Cs, /sup 134/Cs, and /sup 60/Co from both BWR and PWR cement waste forms. The leach rates for both cesium isotopes in cement are at least two orders of magnitude greater than those for cobalt. Leachates from the BWR Dow polymer waste form include the same isotopes present in cement leachates, with the addition of /sup 54/Mn. Cesium leach rates from the Dow polymer waste form are approximately one order of magnitude lower than from an equivalent cement waste form. The /sup 60/Co cumulative fraction release, however, is approximately three times greater for the Dow polymer waste form.
The dosimetry system DS86 and the neutron discrepancy in Hiroshima--historical review, present status, and future options.
Rühm, W; Kellerer, A M; Korschinek, G; Faestermann, T; Knie, K; Rugel, G; Kato, K; Nolte, E
The historical development of the dosimetry systems for Hiroshima and Nagasaki is outlined from the time immediately after the A-bomb explosions to the publication of the dosimetry system DS86 in 1987, and the present status of the so-called Hiroshima neutron discrepancy is summarized. Several long-lived radionuclides are discussed with regard to their production by neutrons from the A-bomb explosions. With the exception of 63Ni, these radionuclides have not, up to now, been measured in samples from Hiroshima and Nagasaki. Two of them, 63Ni in copper samples and 39Ar in granite samples, were predominantly produced by fast neutrons. 63Ni can be determined by accelerator mass spectrometry with a gas-filled analyzing magnet. It should be measurable, in the near future, in copper samples up to 1500 m from the hypocenter in Hiroshima. 39Ar can be measured in terms of low-level beta-counting. This should be feasible up to a distance of about 1000 m from the hypocenter. Three radionuclides, 10Be, 14C, and 59Ni, were produced predominantly by thermal neutrons with smaller fractions due to the epithermal and fast neutrons, which contribute increasingly more at larger distances from the hypocenter. State-of-the-art accelerator mass spectrometry is likely to permit the determination of 10Be close to the hypocenter and of 14C up to a distance of about 1000 m. 59Ni should be detectable up to a distance of about 1000 m in terms of accelerator mass spectrometry with a gas-filled magnet. The measurements of 10Be, 14C, 39Ar, 59Ni -- and potentially of 131Xe -- can be performed in the same granitic sample that was already analyzed for 36Cl, 41Ca, 6Co, 152Eu, and 154Eu. This will provide extensive information on the neutron spectrum at the specified location, and similarly complete analyses can conceivably be performed on granite samples at other locations. PMID:10052679
Tritium-powered radiation sensor network
NASA Astrophysics Data System (ADS)
Litz, Marc S.; Russo, Johnny A.; Katsis, Dimos
Isotope power supplies offer long-lived (100 years using 63Ni), low-power energy sources, enabling sensors or communications nodes for the lifetime of infrastructure. A tritium beta-source (12.5-year half-life) encapsulated in a phosphor-lined vial couples directly to a photovoltaic (PV) to generate a trickle current into an electrical load. An inexpensive design is described using commercial-of-the-shelf (COTS) components that generate 100 μWe for nextgeneration compact electronics/sensors. A matched radiation sensor has been built for long-duration missions utilizing microprocessor-controlled sleep modes, low-power electronic components, and a passive interrupt driven environmental wake-up. The low-power early-warning radiation detector network and isotope power source enables no-maintenance mission lifetimes.
Analysis (Simulation) of Ni-63 beta-voltaic cells based on silicon solar cells
NASA Astrophysics Data System (ADS)
Gorbatsevich, A. A.; Danilin, A. B.; Korneev, V. I.; Magomedbekov, E. P.; Molin, A. A.
Beta-voltaic cells based on standard silicon solar cells with bilateral coating with beta-radiation sources in the form of 63Ni isotope have been studied experimentally and by numerical simulation. The optimal parameters of the cell, including its thickness, the doping level of the substrate, the depth of the p- n junction on its front side, and the p + layer on the back side, as well as the activity of the source material, have been calculated. The limiting theoretical values of the open-circuit voltage (0.26 V), short-circuiting current (2.1 μA), the output power of the cell (0.39 μW), and the efficiency of the conversion of the radioactive energy onto the electric energy (4.8%) have been determined for a beta-source activity of 40 mCi. The results of numerical analysis have been compared with the experimental data.
Beta spectrometry with metallic magnetic calorimeters.
Loidl, M; Rodrigues, M; Le-Bret, C; Mougeot, X
Metallic magnetic calorimeters are a specific type of cryogenic detectors that have been shown to enable precise measurement of the shape of low energy beta spectra. The aim of their use at LNHB is the determination of the shape factors of beta spectra. The beta source is enclosed in the detector absorber, allowing for very high detection efficiency. It has turned out that the type of source is of crucial importance for the correctness of the measured spectrum. Spectra of (63)Ni measured with several sources prepared by drying a NiCl2 solution differ from one another and from theory, whereas spectra measured with electroplated sources are reproducible and agree with theory. With these latter measurements we could confirm the atomic exchange effect down to very low energy (200 eV). PMID:24368065
Direct measurements of neutrino mass
Robertson, R.G.H.
Some recent developments in the experimental search for neutrino mass are discussed. New data from Los Alamos on the electron neutrino mass as measured in tritium beta decay give an upper limit of 9.3 eV at the 95% confidence level. This result is not consistent with the long-standing ITEP result of 26(5) eV within a model-independent'' range of 17 to 40 eV. It now appears that the electron neutrino is not sufficiently massive to close the universe by itself. Hime and Jelley report finding new evidence for a 17-keV neutrino in the {Beta} decay of {sup 35}S and {sup 63}Ni. Many other experiments are being reported and the situation is still unresolved. 56 refs., 1 fig., 3 tabs.
Single and Multi-Nucleon Transfer Reactions for Nuclear Moment Studies Toward Radioactive-Ion Beams
Lozeva, R. L.; Georgiev, G. P.; Audi, G.; Cabaret, S.; Fiori, E.; Gaulard, C.; Hauschilda, K.; Lopez-Martens, A.; Risegari, L.; Blazhev, A.; Jolie, J.; Moschner, K.; Zell, K.-O.; Daugas, J.-M.; Faul, T.; Morel, P.; Roig, O.; Ferraton, M.; Ibrahim, F.
This study is a part of an experimental program to measure nuclear moments in transfer reactions. It aims to probe for a first time the nuclear -spin orientation in multi-nucleon transfer. Fist experiments were performed to measure the quadrupole moment of an isomeric state in {sup 66}Cu (I{sup p}i 6{sup -}, E{sub x} = 1154 keV, T{sub 1/2} = 595(20) ns) in single nucleon transfer and the population of mus isomers in {sup 66}Cu and {sup 63}Ni in multi-nucleon transfer. The experimentally tested methodology allows broad applications toward more exotic species and feasibility of these reactions to produce species away from stability.
National Low-Level Waste Management Program Radionuclide Report Series
J.P. Adams; M.L. Carboneau; W.E. Allred
The National Low Level Waste Management Program at the Idaho National Engineering and Environmental Laboratory has published a report containing key information about selected radionuclides that are most likely to contribute significantly to the radiation exposures estimated from a performance assessment of a low-level radioactive waste (LLW) disposal facility. The information includes physical and chemical characteristics, production means, waste forms, behavior of the radionuclide in soils, plants, groundwater, and air, and biological effects in animals and humans. The radionuclides included in this study comprise all of the nuclides specifically listed in 10CFR61.55, Tables 1 and 2, 3 H, 14 C, 59 Ni, 60 Co, 63 Ni, 90 Sr, 94 Nb, 99 Tc, 129 I, 137 Cs, 241 Pu, and 242 Cm. Other key radionuclides addressed in the report include 237 Np, 238 U, 239 Pu, and 241 Am. This paper summarizes key information contained within this report.
National Low-Level Waste Management Program Radionuclide Report Series
Adams, James Paul; Carboneau, Michael Leonard; Allred, William Edgar
The National Low Level Waste Management Program at the Idaho National Engineering and Environmental Laboratory has published a report containing key information about selected radionuclides that are most likely to contribute significantly to the radiation exposures estimated from a performance assessment of a low-level radioactive waste (LLW) disposal facility. The information includes physical and chemical characteristics, production means, waste forms, behavior of the radionuclide in soils, plants, groundwater, and air, and biological effects in animals and humans. The radionuclides included in this study comprise all of the nuclides specifically listed in 10CFR61.55, Tables 1 and 2, 3 H, 14 C, 59 Ni, 60 Co, 63 Ni, 90 Sr, 94 Nb, 99 Tc, 129 I, 137 Cs, 241 Pu, and 242 Cm. Other key radionuclides addressed in the report include 237 Np, 238 U, 239 Pu, and 241 Am. This paper summarizes key information contained within this report.
Recovery and purification of nickel-63 from HFIR-irradiated targets
Williams, D.F.; O'Kelley, G.D.; Knauer, J.B.; Porter, C.E.; Wiggins, J.T.
The production of large quantities of high-specific-activity [sup 63]Ni (>10 Ci/g) requires both a highly enriched [sup 62]Ni target and a long irradiation period at high neutron flux. Trace impurities in the nickel and associated target materials are also activated and account for a significant fraction of the discharged activity and essentially all of the gamma activity. While most of these undesirable activation products can be removed as chloride complexes during anion exchange, chromium, present at [sup 51]Cr, and scandium, present as [sup 46]Sc, are exceptions and require additional processing to achieve the desired purity. Optimized flowsheets are discussed based upon the current development and production experience.
Critical comparison of radiometric and mass spectrometric methods for the determination of radionuclides in environmental, biological and nuclear waste samples.
Hou, Xiaolin; Roos, Per
The radiometric methods, alpha (alpha)-, beta (beta)-, gamma (gamma)-spectrometry, and mass spectrometric methods, inductively coupled plasma mass spectrometry, accelerator mass spectrometry, thermal ionization mass spectrometry, resonance ionization mass spectrometry, secondary ion mass spectrometry, and glow discharge mass spectrometry are reviewed for the determination of radionuclides. These methods are critically compared for the determination of long-lived radionuclides important for radiation protection, decommissioning of nuclear facilities, repository of nuclear waste, tracer application in the environmental and biological researches, these radionuclides include (3)H, (14)C, (36)Cl, (41)Ca, (59,63)Ni, (89,90)Sr, (99)Tc, (129)I, (135,137)Cs, (210)Pb, (226,228)Ra, (237)Np, (241)Am, and isotopes of thorium, uranium and plutonium. The application of on-line methods (flow injection/sequential injection) for separation of radionuclides and automated determination of radionuclides is also discussed. PMID:18215644
Radioanalytical technology for 10 CFR Part 61 and other selected radionuclides: Literature review
Thomas, C.W.; Thomas, V.W.; Robertson, D.E.
A comprehensive literature review and assessment was conducted to identify and evaluate radioanalytical technology and procedures used for measuring 10CFR61 radionuclides and other long-lived isotopes. This review evaluated radiochemical procedures currently in use at a number of laboratories in the US, as well as identifying new advanced methods and techniques which could be adapted for routine radiochemical analyses of low-level radioactive waste. The 10CFR61 radionuclides include {sup 14}C, {sup 60}Cl, {sup 59,63}Ni, {sup 90}Sr, {sup 94}Nb, {sup 99}Tc, {sup 129}I, {sup 137}Cs, and TRU isotopes with half lives greater than 5 years. Other low-level radionuclides of interest include {sup 7,10}Be, {sup 26}Al, {sup 36}Cl, {sup 93}Mo, {sup 109,113m}Cd, and {sup 121m,126}Sn, which may be present in various types of waste streams from nuclear power stations.
Distribution of nickel hydroxide in sintered nickel plaques measured by radiotracer method during electroimpregnation
Ng, P.K.; Schneider, E.W.
Sintered nickel positive electrodes were prepared by electroimpregnating nickel hydroxide inside a porous nickel plaque in a nickel nitrate solution. The distribution of nickel hydroxide inside the plaque was measured using a radio-tracer method with /sup 63/Ni as the radioactivity source. Autoradiography and ..beta.. counting were used to follow qualitative and quantitative distributions, respectively, of the pore filling process. Relatively uniform distribution was observed at low current density, and the precipitation of Ni(OH)/sub 2/ extends to the center of the plaque. At high current density, most of the Ni(OH)/sub 2/ aggregated in the region just underneath the plaque surface, causing a somewhat nonuniform distribution. Nickel hydroxide also precipitates heavily on the surface of the plaque at high current density, reducing the penetration of electrolyte to the inside of the plaque.
Atmospheric pressure ionization and gas phase ion mobility studies of isomeric dihalogenated benzenes using different ionization techniques
NASA Astrophysics Data System (ADS)
Borsdorf, H.; Nazarov, E. G.; Eiceman, G. A.
Ion mobility spectrometry (IMS) featuring different ionization techniques was used to analyze isomeric ortho-, meta- and para-dihalogenated benzenes in order to assess how structural features affect ion formation and drift behavior. The structure of the product ions formed was investigated by atmospheric pressure chemical ionization (APCI) mass spectrometry (MS) and IMS-MS coupling. Photoionization provided [M]+ ions for chlorinated and fluorinated compounds while bromine was cleaved from isomers of dibromobenzene and bromofluorobenzene. This ionization technique does not permit the different isomers to be distinguished. Comparable ions and additional clustered ions were obtained using 63Ni ionization. Depending on the chemical constitution, different clustered ions were observed in ion mobility spectra for the separate isomers of dichlorobenzene and dibromobenzene. Corona discharge ionization permits the most sensitive detection of dihalogenated compounds. Only clustered product ions were obtained. Corona discharge ionization enables the classification of different structural isomers of dichlorobenzene, dibromobenzene and bromofluorobenzene.
Bioaccumulation and food chain transfer of corrosion products from radioactive stainless steel
Young, J.S.
Two sets of experiments were conducted to determine if corrosion products from radioactive Type 347 stainless steel could be biologically transferred from sediment through a marine food chain, and whether corrosion products dissolved in seawater could be bioaccumulated and then eliminated. Corrosion products containing /sup 60/Co and /sup 63/Ni from the radioactive stainless steel were introduced into marine sediments. Infaunal polychaete worms exposed to these sediments bioaccumulated the radionuclides. The feeding of these worms to shrimp and fish resulted in a trophic transfer of the radioactive products across a one-step food chain. The magnitude of the transfers are described in terms of transfer factors. Dissolved corrosion products as measured by the radionuclides were also bioaccumulated by shrimp and fish concentrating more than fish. Concentration factors were calculated.
Recovery and purification of nickel-63 from HFIR-irradiated targets
Williams, D.F.; O`Kelley, G.D.; Knauer, J.B.; Porter, C.E.; Wiggins, J.T.
The production of large quantities of high-specific-activity {sup 63}Ni (>10 Ci/g) requires both a highly enriched {sup 62}Ni target and a long irradiation period at high neutron flux. Trace impurities in the nickel and associated target materials are also activated and account for a significant fraction of the discharged activity and essentially all of the gamma activity. While most of these undesirable activation products can be removed as chloride complexes during anion exchange, chromium, present at {sup 51}Cr, and scandium, present as {sup 46}Sc, are exceptions and require additional processing to achieve the desired purity. Optimized flowsheets are discussed based upon the current development and production experience.
Determination of ammonia in ethylene using ion mobility spectrometry
NASA Technical Reports Server (NTRS)
Cross, J. H.; Limero, T. F.; Lane, J. L.; Wang, F.
A simple procedure to analyze ammonia in ethylene by ion mobility spectrometry is described. The spectrometer is operated with a silane polymer membrane., 63Ni ion source, H+ (H2O)n reactant ion, and nitrogen drift and source gas. Ethylene containing parts per billion (ppb) (v/v) concentrations of ammonia is pulled across the membrane and diffuses into the spectrometer. Preconcentration or preseparation is unnecessary, because the ethylene in the spectrometer has no noticeable effect on the analytical results. Ethylene does not polymerize in the radioactive source. Ethylene's flammability is negated by the nitrogen inside the spectrometer. Response to ammonia concentrations between 200 ppb and 1.5 ppm is near linear, and a detection limit of 25 ppb is calculated.
Grain boundary and triple junction diffusion in nanocrystalline copper
Wegner, M. Leuthold, J.; Peterlechner, M.; Divinski, S. V.; Song, X.; Wilde, G.
Grain boundary and triple junction diffusion in nanocrystalline Cu samples with grain sizes, 〈d〉, of ∼35 and ∼44 nm produced by spark plasma sintering were investigated by the radiotracer method using the {sup 63}Ni isotope. The measured diffusivities, D{sub eff}, are comparable with those determined previously for Ni grain boundary diffusion in well-annealed, high purity, coarse grained, polycrystalline copper, substantiating the absence of a grain size effect on the kinetic properties of grain boundaries in a nanocrystalline material at grain sizes d ≥ 35 nm. Simultaneously, the analysis predicts that if triple junction diffusion of Ni in Cu is enhanced with respect to the corresponding grain boundary diffusion rate, it is still less than 500⋅D{sub gb} within the temperature interval from 420 K to 470 K.
Determination of pyrethroid residues in tobacco and cigarette smoke by capillary gas chromatography.
Cai, Jibao; Liu, Baizhan; Zhu, Xiaolan; Su, Qingde
The extraction of fenpropathrin, cyhalothrin, cypermethrin, fenvalerate and deltamethrin from tobacco (Nicotina tobaccum) and cigarette smoke condensate with acetone, followed by partition of resulting acetone mixture with petroleum ether, was investigated and found suitable for capillary gas chromatography (GC) residue analysis. Florisil column clean-up was found to provide clean-up procedure for tobacco and cigarette smoke condensate permitting analysis to < or = 0.01 microgram.g-1 for most of the pyrethroids by GC with a 63Ni electron capture detector (GC-ECD). Quantitative determination was obtained by the method of external standards. Cigarettes made from flue-cured tobacco spiked with different amounts of pyrethroids were used and the pyrethroid levels in mainstream smoke were determined. For all the pyrethroid residues, 1.51-15.50% were transferred from tobacco into cigarette smoke. PMID:12198849
Atmospheric pressure ion focusing with a vortex stream.
Kolomiets, Yuri N; Pervukhin, Viktor V
For successful operation of ionization analysis techniques an efficient sampling and sample ion transportation into an analytical path are required. This is of particular importance for atmospheric pressure ionization sources like corona discharge, electrospray, MALDI, ionization with radioactive isotopes ((3)H, (63)Ni) that produce nonuniform spatial distribution of sample ions. The available methods of sample ion focusing with electric fields are either efficient at reduced pressure (to 1 Torr) or feature high sample losses. In this paper we suggest to use a highly whirled gas stream for atmospheric pressure ion focusing. We use a (63)Ni radioactive source to produce an ionized bipolar sample at atmospheric pressure. It is shown by experiments that compared to an aspiration method a forced highly whirled vortex stream allows one to enhance the efficiency of remote ionized sample collection at distances equal to the vortex sampler diameter by an order of magnitude. With a vortex stream, a sixfold increase in the efficiency of the radial ionized sample collection has been obtained. It may be deduced that with the vortex stream remote sampling obtains a new feature which is characterized by a considerable enhancement of the efficiency of the ionized sample collection and can be called as a "gas-dynamic" ionized sample focusing. Considered is the effect of recombination losses of the ionized sample during the remote sampling thereof with the vortex sampler. Prospects for a practical implementation of the vortex sampler for solving the problems of the customs control over the smuggling of radioactive α and β sources are made based on the research results. PMID:21872021
Toxicology and metabolism of nickel compounds. Progress report, December 1, 1983-November 30, 1984
Sunderman, F.W. Jr.
The toxicology of nickel compounds (e.g., NiCl/sub 2/, Ni/sub 3/S/sub 2/, Ni(CO)/sub 4/) was investigated in rats. The following new knowledge was acquired: (1) renal cytosol from /sup 63/NiCl/sub 2/-treated rats contains at least ten /sup 63/Ni-binding proteins and polypeptides with molecular weights ranging from 168,000 to <4,000 daltons; (2) parenteral administration of NiCl/sub 2/ to rats transiently diminishes hepatic concentrations of reduced and oxidized glutathione and enhances lipid peroxidation; (3) tetraethylenepentamine is equally effective as diethyldithiocarbamate as an antidote for acute Ni(CO)/sub 4/ poisoning in rats; (4) Ni(II)-induction of heme oxygenase activity in rat kidney is sustained for only 3 days of repeated treatments and thereafter gradually decreases, indicating adaptive tolerance for Ni(II) toxicity; (5) carcinogenesis bioassays of 17 nickel compounds by ir administration to rats demonstrate close correlation between the induction of erythrocytosis at 1 to 4 months post-injection and the subsequent incidence of renal cancers; (6) immunoreactive erythropoietin concentration is increased in kidney extracts of rats following ir injection of Ni/sub 3/S/sub 2/, supporting the role of erythropoietin in Ni/sub 3/S/sub 2/-induced erythrocytosis; (7) arteriosclerotic lesions in Ni/sub 3/S/sub 2/-treated rats can be visualized by focal fluorescence of hematoporphyrin derivative injected iv 24 hours prior to necropsy; and (8) marked hypernickelemia is a consistent finding in patients with endstage renal disease receiving chronic hemodialysis treatment. 13 references.
Bioavailability of iron from a traditional Tunisian meal with chickpeas fed to healthy rats.
Hamdaoui, M; Doghri, T; Tritar, B
The influence of a diet of couscous with chickpeas, a traditional Tunisian meal, or one providing iron as ferrous sulfate, on the utilization of 59Fe was evaluated in studies with rats. The iron content of the couscous and chickpea preparation was 30 mg/kg dry weight. There was no difference in the relative absorption of iron from ferrous sulfate or couscous with chickpeas, suggesting that iron from this preparation may be a good dietary source of nonheme iron for rats. Couscous and chickpeas consumption in Tunisia are estimated at 13.3 and 3.2 kg per capita/year, respectively. Our results in rats indicate that these foods could contribute a large proportion of an individual's iron requirement. We conclude that the plant foods, especially the chickpeas, can be excellent sources of dietary-available iron. PMID:1530281
Direct magnetocaloric measurements of Fe-B-Cr-X (X = La, Ce) amorphous ribbons
NASA Astrophysics Data System (ADS)
Law, J. Y.; Franco, V.; Ramanujan, R. V.
A procedure has been developed to directly measure the adiabatic temperature change of amorphous melt-spun Fe-based ribbons displaying attractive room temperature magnetocaloric properties. Polycrystalline Gd ribbons are used as a reference material to compensate for the contribution of the sample holder to the experimental values. Fe78B12Cr8Ce2 and Fe75B12Cr8Ce5 melt-spun ribbons exhibited a peak adiabatic temperature change (ΔTadpk) ˜ 58% larger than Co82.9Si5.9Fe4.5Cr4B2.7 amorphous ribbons. The ΔTadpk in Fe78B12Cr8Ce2, Fe75B12Cr8Ce5, and Fe79B12Cr8La1 ribbons displayed ˜ 18-33% enhanced ΔTadpk compared to a GdAl2 alloy.
A pharmacokinetic and clinical evaluation of iron poly (sorbitol-gluconic acid) complex.
Campbell, B C; Lawrence, J R; Sumner, D J; Kelman, A; Smith, A; Elliott, H L; Goldberg, A
The pharmacokinetics of iron poly (sorbitol-gluconic acid) complex (IPSG) were studied following a single intramuscular injection of 59Fe-labelled IPSG to 4 iron deficient-patients. The results showed a more rapid uptake of iron from the site of injection than that reported with iron dextran while there was a lower urinary excretion than found with iron sorbitol citrate. A clinical study was carried out in 11 patients with iron deficiency anaemia. Patients were allocated at random to receive IPSG as either 250 mg or 500 mg elemental iron per week for 8 weeks. A satisfactory response to therapy was obtained with each regimen whether measured by an increase in haemoglobin concentration or in serum ferritin concentration. Few side-effects were encountered but discomfort and staining at the injection site was found on the higher dose schedule. PMID:7208542
Relationship between erythrocyte volume and cell age in humans and baboons. Technical report
Thompson, C.B.; Galli, R.L.; Melaragno, A.J.; Valeri, C.R.
The relationship of red blood cell size to age during steady-state hematopoiesis has been studied using erythrocytes separated on the basis of size using counterflow centrifugation. The ratio of the age-related enzyme, erythrocyte glutamic oxaloacetic transferase (EGOT), to hemoglobin (Hb) increased progressively through the fractions, suggesting a correlation between erythrocyte volume and age. Reticulocytes, while present in all fractions, were selectively enriched in the larger subpopulations. To verify the biochemical evidence that erythrocytes decrease in volume with aging, in vivo cohort labeling of red blood cells with 59Fe was performed in baboons. A similar relationship of EGOT to Hb was observed to that in the human subpopulations. While a certain amount of erythrocyte volume heterogeneity seems to be present as a result of erythropoeisis, our data support the hypothesis that red blood cells decrease in volume as they age.
Monoclonal antibodies to Pseudomonas aeruginosa ferripyochelin-binding protein.
Sokol, P A; Woods, D E
Hybridomas secreting specific monoclonal antibodies against the Pseudomonas aeruginosa ferripyochelin-binding protein (FBP) were isolated. These monoclonal antibodies reacted with FBP in immunoblots of outer membrane preparations from all serotypes of P. aeruginosa. Two of the monoclonal antibodies also reacted with FBP in strains of P. putida, P. fluorescens, and P. stutzeri. These antibodies did not react with outer membranes of P. cepacia, "P. multivorans," P. maltophilia, or other gram-negative organisms. The monoclonal antibodies were opsonophagocytic and blocked the binding of [59Fe]ferripyochelin to isolated outer membranes of strain PAO. By indirect immunofluorescence techniques, the monoclonal antibodies were used to demonstrate that FBP is present on the cell surface of P. aeruginosa cells grown in low-iron but not high-iron medium. These observations were confirmed by using 125I in surface-labeling techniques. Images PMID:3091506
Characterization of anemia induced by avian osteopetrosis virus.
Paterson, R W; Smith, R E
Chickens infected intravenously at 8 days after hatching with an avian osteopetrosis virus developed a severe, progressive anemia in the absence of osteopetrosis. The anemia was characterized as a pancytopenia, in which erythrocytes, granulocytes, and thrombocytes decreased concomitantly. Serum bilirubin levels were normal, whereas erythrocytes from infected chickens demonstrated a slightly elevated osmotic fragility. A negative Coombs test indicated that there was no evidence for erythrocyte-bound antibody. Erythrocytes from infected animals had slightly decreased 51Cr-labeled erythrocyte survival time when compared with normal. Examination of marrow histological preparations, together with ferrokinetic studies with 59Fe, indicated that marrow failure occurred during the acute phase of the anemia. Circulating virus was present during the development and acute phases of the anemia, but disappeared during the recovery phase of the disease. Neutralizing antibody appeared after the disappearance of circulating virus. It is concluded that virus infection induced both marrow failure (aplastic crisis) and decreased erythrocyte survival. Images PMID:215554
[Results of measuring the charge and energy spectra of heavy nuclei on board the artificial Earth satellite Kosmos-936].
Dashin, S A; Marennyĭ, A M; Gertsen, G P
The measurements were performed using a package of dielectric track detectors mounted behind the shield of 60-80 kg.m-2 thick. The charge of nuclei was determined from the complete track length. As a result, 1915 tracks of nuclei with Z greater than or equal to 6 in the energy range 100-450 MeV/nuclon were detected and identified. The differential charge spectrum of nuclei with 6 less than or equal to Z less than or equal to 28 and the energy spectrum of nuclei of the iron group were built. For iron nuclei the following ration of isotope groups was obtained: (Fe52 + Fe53 + Fe54): (Fe55 + Fe56 + Fe57) : (Fe58 + Fe59 + Fe60) = (0.30 +/- 0.08) = (0.49 +/- 0.10) : (0.21 +/- 0.05). PMID:7098416
Role of bilirubin overproduction in revealing Gilbert's syndrome: is dyserythropoiesis an important factor?
Metreau, J M; Yvart, J; Dhumeaux, D; Berthelot, P
Gilbert's syndrome was diagnosed in 37 patients with unconjugated hyperbilirubinaemia without overt haemolysis or structural liver abnormality, who had a marked reduction in hepatic bilirubin UDP-glucuronosyltransferase activity (B-GTA) (as compared with that of 23 normal subjects). No significant correlation existed in these patients between serum bilirubin level and the values of B-GTA, thus suggesting that factors other than a low B-GTA must influence the degree of hyperbilirubinaemia in Gilbert's syndrome. Studies of 51Cr erythrocyte survival and 59Fe kinetics in 10 unselected patients demonstrated slight haemolysis in eight, whereas mild ineffective erythropoiesis was suggested in all from a low 24-hour incorporation of radioactive iron into circulating red cells. This overproduction of bilirubin resulting from mild haemolysis and perhaps dyserythropoiesis might reflect only an extreme degree of the normal situation. It certainly contributes to the hyperbilirubinaemia of Gilbert's syndrome and may play a major role in the manifestation of this condition. PMID:101425
Multidentate terephthalamidate and hydroxypyridonate ligands: towards new orally active chelators.
Abergel, Rebecca J; Raymond, Kenneth N
The limitations of current therapies for the treatment of iron overload or radioisotope contamination have stimulated efforts to develop new orally bioavailable iron and actinide chelators. Siderophore-inspired tetradentate, hexadentate and octadentate terephthalamidate and hydroxypyridonate ligands were evaluated in vivo as selective and efficacious iron or actinide chelating agents, with several metal loading and ligand assessment procedures, using (59)Fe, (238)Pu, and (241)Am as radioactive tracers. The compounds presented in this study were compared to commercially available therapeutic sequestering agents [deferoxamine (DFO) for iron and diethylenetriaminepentaacetic acid (DPTA) for actinides] and are unrivaled in terms of affinity, selectivity and decorporation efficacy, which attests to the fact that high metal affinity may overcome the low bioavailability properties commonly associated to multidenticity. PMID:21599440
Abergel, Rebecca J.; Raymond, Kenneth N.
The limitations of current therapies for the treatment of iron overload or radioisotope contamination have stimulated efforts to develop new orally bioavailable iron and actinide chelators. Siderophore-inspired tetradentate, hexadentate and octadentate terephthalamidate and hydroxypyridonate ligands were evaluated in vivo as selective and efficacious iron or actinide chelating agents, with several metal loading and ligand assessment procedures, using {sup 59}Fe, {sup 238}Pu, and {sup 241}Am as radioactive tracers. The compounds presented in this study were compared to commercially available therapeutic sequestering agents [deferoxamine (DFO) for iron and diethylenetriaminepentaacetic acid (DPTA) for actinides] and are unrivaled in terms of affinity, selectivity and decorporation efficacy, which attests to the fact that high metal affinity may overcome the low bioavailability properties commonly associated to multidenticity.
Depressed eruption rate of the rat maxillary incisor in a drug-induced uncompensated hemolytic state model
Giglio, M.J.; Sanz, A.M.; Bozzini, C.E. )
Female rats weighing about 180 g were separated into two groups. One group (A) received phenylhydrazine (PHZ) every other day during three weeks (for induction of an uncompensated hemolytic state), while the control group (C) received saline. The evidence for the establishment of the uncompensated hemolytic state was obtained by hematocrit value, reticulocyte count, and red-cell-volume-59Fe uptake. Body-weight gain (which is a measure of overall body growth rate), body-length gain (which is a measure of longitudinal skeletal growth rate), food intake, and maxillary incisor eruption rate (ER) were significantly depressed in rats of group A during the PHZ-injection period, in relation to rats of group C. These results indicate that anemia and/or associated factors depress ER, along with body growth and skeletal growth.
Ferrokinetic and erythrocyte survival studies in healthy and anemic cats
Madewell, B.R.; Holmes, P.H.; Onions, D.E.
Erythrocyte survival and ferrokinetic studies were adapted to the cat. For 5 clinically healthy 4- to 9-month-old cats, mean /sup 51/Cr-labeled erythrocyte survival was 144 hours, and mean plasma /sup 59/Fe-labeled transferrin disappearance halftime was 51 minutes. Erythrocyte use of radioiron was rapid and efficient, with 50% to 80% of labeled iron incorporated into the erythron by 100 hours after injection into the cat. Six cats with feline leukemia virus infection were studied. For 2 cats with erythroid aplasia associated with C subgroup of feline leukemia virus, erythrocyte survival times were similar to those determined for the healthy cats, but plasma radioiron disappearance half time and erythrocyte use of radioiron were markedly diminished.
Probiotic strain Lactobacillus plantarum 299v increases iron absorption from an iron-supplemented fruit drink: a double-isotope cross-over single-blind study in women of reproductive age.
Hoppe, Michael; Önning, Gunilla; Berggren, Anna; Hulthén, Lena
Iron deficiency is common, especially among young women. Adding probiotics to foods could be one way to increase iron absorption. The aim of this study was to test the hypothesis that non-haem iron absorption from a fruit drink is improved by adding Lactobacillus plantarum 299v (Lp299v). Iron absorption was studied in healthy women of reproductive age using a single-blind cross-over design in two trials applying the double-isotope (55Fe and 59Fe) technique. In Trial 1, iron absorption from a fruit drink containing 109 colony-forming units (CFU) Lp299v was compared with that from a control drink without Lp299v. Trial 2 had the same design but 1010 CFU were used. The test and control drinks contained approximately 5 mg of iron as ferrous lactate and were labelled with 59Fe (B) and 55Fe (A), respectively, and consumed on 4 consecutive days in the order AABB. Retention of the isotopes was measured with whole-body counting and in blood. Mean iron absorption from the drink containing 109 CFU Lp299v (28·6(sd 12·5) %) was significantly higher than from the control drink (18·5(sd 5·8) %), n 10, P<0·028). The fruit drink with 1010 CFU Lp299v gave a mean iron absorption of 29·1(sd 17·0) %, whereas the control drink gave an absorption of (20·1(sd 6·4) %) (n 11, P<0·080). The difference in iron absorption between the 109 CFU Lp299v and the 1010 CFU Lp299v drinks was not significant (P=0·941). In conclusion, intake of probiotics can increase iron absorption by approximately 50 % from a fruit drink having an already relatively high iron bioavailability. PMID:26428277
The effect of copper and gallium compounds on ribonucleotide reductase
Narasimhan, J.
The mode of action of copper complexes (CuL and CuKTS) and gallium compounds (gallium nitrate and citrate) in cytotoxicity was studied. The effects of these agents on the enzyme ribonucleotide reductase was investigated by monitoring the tyrosyl free radical present in the active site of the enzyme through electron spin resonance (ESR) spectroscopy. Ribonucleotide reductase, a key enzyme in cellular proliferation, consists of two subunits. M1, a dimer of molecular weight 170,000 contains the substrate and effector binding sites. M2, a dimer of molecular weight 88,000, contains non-heme iron and tyrosyl free radical essential for the activity of the enzyme. In studies using copper complexes, the cellular oxidative chemistry was examined by ESR studies on adduct formation with membranes, and oxidation of thiols. Membrane thiols were oxidized through the reduction of the ESR signal of the thiol adduct and the analysis of sulfhydryl content. Using the radiolabel [sup 59]Fe, the inhibitory action of copper thiosemicarbazones on cellular iron uptake was shown. The inhibitory action of CuL on ribonucleotide reductase was shown by the quenching of the tyrosyl free radical on the M2 subunit. The hypothesis that gallium directly interacts with the M2 subunit of the enzyme and displaces the iron from it was proven. The tyrosyl free radical signal from cell lysates was inhibited by the direct addition of gallium compounds. Gallium content in the cells was measured by a fluorimetric method, to ensure the presence of sufficient amounts of gallium to compete with the iron in the M2 subunit. The enzyme activity, measured by the conversion of [sup 14]C-CDP to the labeled deoxy CDP, was inhibited by the addition of gallium nitrate in a cell free assay system. The immunoprecipitation studies of the [sup 59]Fe labeled M2 protein using the monoclonal antibody directed against this subunit suggested that gallium releases iron from the M2 subunit.
Basis of Plasma Iron Exchange in the Rabbit
Huebers, Helmut; Uvelli, David; Celada, Antonio; Josephson, Betty; Finch, Clement
Rabbit transferrin in vitro is shown to load ferrous iron at random on its specific binding sites. The release of iron to reticulocytes is shown to be an all-or-none phenomenon. The two monoferric transferrins have similar in vivo plasma iron clearance rates and tissue distribution. Diferric transferrin, while giving a similar tissue distribution of radioiron, has a plasma iron clearance rate approximately twice that of the monoferric transferrins at low plasma iron concentrations. This difference diminishes as the plasma iron concentration increases. These results are consistent with a progressively greater in vivo conversion of mono- to diferric transferrin as transferrin saturation increases. The in vivo plasma iron turnover in the rabbit increases progressively as the plasma iron increases, from a mean value of ∼0.8 mg/dl whole blood per d at a plasma iron concentration of 50 μg/dl to 2.0 at a plasma iron concentration of 300. The molecular behavior of transferrin and its iron over this range was investigated using 125I-transferrin, [55Fe]monoferric transferrin, and [59Fe]diferric transferrin. The equilibrium distribution of transferrin between its apo-, mono-, and diferric moieties was similar to that predicted on the basis of the percent saturation and random distribution. Rate constants of iron loading and unloading calculated from the percent saturation and from the clearance rates of [55Fe]monoferric and [59Fe]diferric transferrin were similar to those derived from changes in injected 125I-apotransferrin. On the basis of these data, it is concluded that the plasma transferrin pool is nonhomogeneous and that the relative size of the mono- and diferric cycles depends on transferrin saturation. A formula is proposed for correcting the plasma iron turnover, thereby eliminating the effect of plasma iron concentration, so as to reflect directly the number of tissue transferrin receptors. PMID:7119114
Bioaccumulation of radionuclides in fertilized Canadian Shield lake basins.
Bird, G A; Hesslein, R H; Mills, K H; Schwartz, W J; Turner, M A
Radionuclide tracers of heavy metals (59Fe, 60Co, 65Zn, 75Se, 85Sr, 134Cs and 203Hg) representing potential contamination from nuclear power plants, industry and agriculture were added to separate basins of Lake 226, Experimental Lakes Area, northwestern Ontario. The two basins were part of a eutrophication experiment and differed in their trophic status; the north basin (L226N) was eutrophic whereas the south basin (L226S) was mesotrophic. Our objective was to determine the uptake of the radionuclides by biota and the effect of lake trophic status on their bioaccumulation. The trophic status of the lakes did not appear to have a marked effect on the accumulation of radionuclides by the biota. This may have been because of a mid-summer leakage of nutrients between the basins which enhanced primary production in L226S, because there is a time lag between primary production and the availability of the radionuclides to the fishes or because trophic status does not affect the uptake of at least some of these radionuclides. However, there was a tendency for faster uptake of the radionuclides in L226N by fish than L226S, but the differences were not significant. Concentrations in the biota generally decreased in the order: fathead minnow > pearl dace > tadpoles > slimy sculpin > leeches. Concentrations in biota generally decreased in the order. 65Zn > 203Hg > 75Se > 134Cs > 60Co > 85Sr = 59Fe. Cobalt-60 concentrations in tadpoles were greater than in the other biota. Radionuclide concentrations in the tissues of lake whitefish indicated that uptake was predominantly from food. Radionuclide concentrations were usually higher in the posterior gut, liver and kidney than in other tissues, whereas body burdens were generally high in the muscle for 75Se, 134Cs and 203Hg; kidney and gut for 60Co; and bone for 65Zn and 75Se. Mercury-203 burdens were also high in the bone and gut. PMID:9718743
Response of respiratory components in x-irradiated Micrococcus radiodurans
Dooley, D.A.
Iron-containing cytochromes provide energy to repair radiation damage. The cytochromes of Micrococcus radiodurans are atypical in that they strongly resist reduction by sodium hydrosulfite or oxidation by potassium ferricyanide, but are typically highly sensitive to potassium cyanide inhibition of respiration. Respiration in this organism is highly resistant to radiation damage, being reduced to 60% of the control level 2 hours after an exposure of 600 kR, whereas other bacteria, such as E. coli, are reduced to near zero. This reduction in respiration may be due either to a defect produced in existing cytochromes or to a decrease in synthesis of new cytochromes. Growth in low iron medium yields reductions in growth rate, oxygen consumption per cell and radioresistance, the shoulder of the survival curve being obliterated. Analysis of /sup 59/Fe-labeled cell contents on Sephadex G-200 immediately following exposure shows little change in elution patterns of the cytochromes. Only about 7% of /sup 59/Fe label is lost from cells after 3 hours of incubation in YHC following 600 kR. No immediate loss of label is detected up to total exposures of 750 kR. The uptake of iron following x-ray exposure shows a depression of 40% of control at 600 kR. Incubation of labeled cells in Triton X-100 (0.25%, v/v) releases 20% of the total activity in 5 minutes. Spectral analysis of this material reveals the presence of both pigmentation and cytochrome. These observations suggest that very high doses of radiation do not produce gross structural changes in existing cytochromes, but their respiratory function is depressed. The delay exhibited in the depression of respiratory function may be the result of initial protein damage followed by some type of proteolytic degradation since there is an immediate decrease in iron uptake post-irradiation with no subsequent recovery even at sublethal exposures.
In Vitro Characterization of the Pharmacological Properties of the Anti-Cancer Chelator, Bp4eT, and Its Phase I Metabolites
Potůčková, Eliška; Roh, Jaroslav; Macháček, Miloslav; Sahni, Sumit; Stariat, Ján; Šesták, Vít; Jansová, Hana; Hašková, Pavlína; Jirkovská, Anna; Vávrová, Kateřina; Kovaříková, Petra; Kalinowski, Danuta S.; Richardson, Des R.; Šimůnek, Tomáš
Cancer cells have a high iron requirement and many experimental studies, as well as clinical trials, have demonstrated that iron chelators are potential anti-cancer agents. The ligand, 2-benzoylpyridine 4-ethyl-3-thiosemicarbazone (Bp4eT), demonstrates both potent anti-neoplastic and anti-retroviral properties. In this study, Bp4eT and its recently identified amidrazone and semicarbazone metabolites were examined and compared with respect to their anti-proliferative activity towards cancer cells (HL-60 human promyelocytic leukemia, MCF-7 human breast adenocarcinoma, HCT116 human colon carcinoma and A549 human lung adenocarcinoma), non-cancerous cells (H9c2 neonatal rat-derived cardiomyoblasts and 3T3 mouse embryo fibroblasts) and their interaction with intracellular iron pools. Bp4eT was demonstrated to be a highly potent and selective anti-neoplastic agent that induces S phase cell cycle arrest, mitochondrial depolarization and apoptosis in MCF-7 cells. Both semicarbazone and amidrazone metabolites showed at least a 300-fold decrease in cytotoxic activity than Bp4eT towards both cancer and normal cell lines. The metabolites also lost the ability to: (1) promote the redox cycling of iron; (2) bind and mobilize iron from labile intracellular pools; and (3) prevent 59Fe uptake from 59Fe-labeled transferrin by MCF-7 cells. Hence, this study demonstrates that the highly active ligand, Bp4eT, is metabolized to non-toxic and pharmacologically inactive analogs, which most likely contribute to its favorable pharmacological profile. These findings are important for the further development of this drug candidate and contribute to the understanding of the structure-activity relationships of these agents. PMID:26460540
The mammalian transferrin-independent iron transport system may involve a surface ferrireductase activity.
Jordan, I; Kaplan, J
Mammalian cells accumulate iron from ferric citrate or ferric nitrilotriacetate through the activity of a transferrin-independent iron transport system [Sturrock, Alexander, Lamb, Craven and Kaplan (1990) J. Biol. Chem. 265, 3139-3145]. The uptake system might recognize and transport ferric-anion complexes, or cells may reduce ferric iron at the surface and then transport ferrous iron. To distinguish between these possibilities we exposed cells to either [59Fe]ferric citrate or ferric [14C]citrate and determined whether accumulation of iron was accompanied by the obligatory accumulation of citrate. In HeLa cells and human skin fibroblasts the rate of accumulation of iron was three to five times greater than that of citrate. Incubation of fibroblasts with ferric citrate or ferric ammonium citrate resulted in an enhanced accumulation of iron and citrate; the molar ratio of accumulation approaching unity. A similar rate of citrate accumulation, however, was observed when ferric citrate-incubated cells were exposed to [14C]citrate alone. Further studies demonstrated the independence of iron and citrate accumulation: addition of unlabelled citrate to cells decreased the uptake of labelled citrate without affecting the accumulation of 59Fe; iron uptake was decreased by the addition of ferrous chelators whereas the uptake of citrate was unaffected; reduction of ferric iron by ascorbate increased the uptake of iron but had no effect on the uptake of citrate. When HeLa cells were depleted of calcium, iron uptake decreased, but there was little effect on citrate uptake. These results indicate that transport of iron does not require the obligatory transport of citrate and vice versa. The mammalian transferrin-independent iron transport system appears functionally similar to iron transport systems in both the bacterial and plant kingdoms which require the activities of both a surface reductase and a ferrous metal transporter. PMID:7945215
Manganese chromium isotope systematics of carbonaceous chondrites
NASA Astrophysics Data System (ADS)
Shukolyukov, A.; Lugmair, G. W.
In this article we present the results of Cr isotope investigations of different types of carbonaceous chondrites and of the pallasite Eagle Station. The 53Cr/ 52Cr ratios in the bulk samples of carbonaceous chondrites are correlated with 55Mn/ 52Cr ratios. The slope of the correlation line yields a 53Mn/ 55Mn ratio of (8.5 ± 1.5) × 10 - 6 at the time of Mn/Cr fractionation. Mapping this ratio onto an absolute time scale yields a time for this event of 4568.1 + 0.8/- 1.1 Ma ago. This time is very similar to the formation age of Efremovka CAIs of 4567.2 ± 0.6 Ma [Y. Amelin, A. N. Krot, I. D. Hutcheon, A. A. Ulyanov, Lead isotopic ages of chondrules and calcium-aluminum-rich inclusions, Science 297 (2002) 1678-1683], to a time of the chondrule formation of 4568 ± 1 Ma ago [L.E. Nyquist, D. Lindstrom, D. Mittlefehldt, C.-Y. Shih, H. Wiesmann, S. Wentworth, R. Martinez, Manganese-chromium formation intervals for chondrules from the Bishunpur and Chainpur meteorites, Meteorit. Planet. Sci. 36 (2001) 911-938], which, most likely, constrains early global high-temperature Mn/Cr fractionation in a nebular setting. The bulk samples of carbonaceous chondrites exhibit clear 54Cr excesses ( 54Cr *) that are correlated with the 53Cr excesses ( 53Cr *) and also with Mn/Cr ratios. One possible explanation of this correlation is that 54Cr * is also radiogenic, like 53Cr *, and was formed by the decay of the short-lived parent radionuclide 54Mn. The very short half-life of 54Mn of 312 days would require that both short-lived radionuclides 53Mn and 54Mn were generated locally in spallation reactions during the early period of an active sun. The alternative and possibly more plausible explanation is the heterogeneous addition of presolar material. The presolar component, enriched in 54Cr, is mostly contained in the matrix of carbonaceous chondrites. The relative amount of matrix decreases in the sequence CI > CM > CO,CV. A large proportion of Mn is associated with the matrix while
Anthropogenic radionuclide fluxes and distribution in bottom sediments of the cooling basin of the Ignalina Nuclear Power Plant.
Marčiulionienė, D; Mažeika, J; Lukšienė, B; Jefanova, O; Mikalauskienė, R; Paškauskas, R
Based on γ-ray emitting artificial radionuclide spectrometric measurements, an assessment of areal and vertical distribution of (137)Cs, (60)Co and (54)Mn activity concentrations in bottom sediments of Lake Drūkšiai was performed. Samples of bottom sediments from seven monitoring stations within the cooling basin were collected in 1988-1996 and 2007-2010 (in July-August). For radionuclide areal distribution analysis, samples from the surface 0-5 cm layer were used. Multi sample cores sliced 2 cm, 3 cm or 5 cm thick were used to study the vertical distribution of radionuclides. The lowest (137)Cs activity concentrations were obtained for two stations that were situated close to channels with radionuclide discharges, but with sediments that had a significantly smaller fraction of organic matter related to finest particles and consequently smaller radionuclide retention potential. The (137)Cs activity concentration was distributed quite evenly in the bottom sediments from other investigated monitoring stations. The highest (137)Cs activity concentrations in the bottom sediments of Lake Drūkšiai were measured in the period of 1988-1989; in 1990, the (137)Cs activity concentrations slightly decreased and they varied insignificantly over the investigation period. The obtained (238)Pu/(239,240)Pu activity ratio values in the bottom sediments of Lake Drūkšiai represented radioactive pollution with plutonium from nuclear weapon tests. Higher (60)Co and (54)Mn activity concentrations were observed in the monitoring stations that were close to the impact zones of the technical water outlet channel and industrial rain drainage system channel. (60)Co and (54)Mn activity concentrations in the bottom sediments of Lake Drūkšiai significantly decreased when operations at both INPP reactor units were stopped. The vertical distribution of radionuclides in bottom sediments revealed complicated sedimentation features, which may have been affected by a number of natural and
Gamma-ray spectrometry of LDEF samples
Winn, W.G.
A total of 31 samples from the Long Duration Exposure Facility (LDEF), including materials of aluminum, vanadium, and steel trunnions were analyzed by ultra-low-level gamma spectroscopy. The study quantified particle induced activations of (sup 22)Na, {sup 46}Sc, {sup 51}Cr, {sup 54}Mn, {sup 56}Co, {sup 57}Co, {sup 58}Co, and {sup 60}Co. The samples of trunnion sections exhibited increasing activity toward the outer end of the trunnion and decreasing activity toward its radial center. The trunnion sections did not include end pieces, which have been reported to collect noticeable {sup 7}Be on their leading surfaces. No significant {sup 7}Be was detected in the samples analyzed. The Underground Counting Facility at Savannah River Laboratory (SRL) was used in this work. The facility is 50 ft. underground, constructed with low-background shielding materials, and operated as a clean room. The most sensitive analyses were performed with a 90%-efficient HPGe gamma-ray detector, which is enclosed in a purged active/passive shield. Each sample was counted for one to six days in two orientations to yield more representative average activities for the sample. The non-standard geometries of the LDEF samples prompted the development of a novel calibration method, whereby the efficiency about the samples surfaces (measured with point sources) predicted the efficiency for the bulk sample.
Instrument for precision long-term β-decay rate measurements.
Ware, M J; Bergeson, S D; Ellsworth, J E; Groesbeck, M; Hansen, J E; Pace, D; Peatross, J
We describe an experimental setup for making precision measurements of relative β-decay rates of (22)Na, (36)Cl, (54)Mn, (60)Co, (90)Sr, (133)Ba, (137)Cs, (152)Eu, and (154)Eu. The radioactive samples are mounted in two automated sample changers that sequentially position the samples with high spatial precision in front of sets of detectors. The set of detectors for one sample changer consists of four Geiger-Müller (GM) tubes and the other set of detectors consists of two NaI scintillators. The statistical uncertainty in the count rate is few times 0.01% per day for the GM detectors and about 0.01% per hour on the NaI detectors. The sample changers, detectors, and associated electronics are housed in a sealed chamber held at constant absolute pressure, humidity, and temperature to isolate the experiment from environmental variations. The apparatus is designed to accumulate statistics over many years in a regulated environment to test recent claims of small annual variations in the decay rates. We demonstrate that absent this environmental regulation, uncontrolled natural atmospheric pressure variations at our location would imprint an annual signal of 0.1% on the Geiger-Müller count rate. However, neither natural pressure variations nor plausible indoor room temperature variations cause a discernible influence on our NaI scintillator detector count rate. PMID:26233381
Radioactive effluents in Savannah River. Summary Report for 1995
Winn, W.G.
During 1995, the radioactive effluents in the Savannah River were generally lower but comparable to those observed during the earlier years of these studies, being orders of magnitude below DOE and EPA/CFR guide levels. Vogtle has only one notable effluent release in 1995. In earlier year, Vogtle effluents had been dominated by {sub 58}Co; however, in 1995 {sub 60}Co exhibited the overall maximum at 1.31 pCi/L, which is almost three times larger than the previous {sub 60}Co maximum of 0.49 pCi/L observed in 1988. By comparison, the {sub 58}Co maximum was 0.46 pCi/L, which was lower than its maxima in earlier years. In addition to {sub 58}Co and {sub 60}Co, Vogtle activities of {sub 54}Mn, {sub 57}Co, {sub 95}Nb, and {sub 95}Zr were observed. The above activities were observed from samples just downstream of Vogtle, but these samples were discontinued in October due to funding priorities. In addition, {sub 137}Cs was detected, but its levels are consistent with known SRS sources. The maximum for {sub 137}Cs was 49 fCi/L at Highway 301 Bridge.
A trapezoid approach for the experimental total-to-peak efficiency curve used in the determination of true coincidence summing correction factors in a HPGe detector
NASA Astrophysics Data System (ADS)
Şahiner, Eren; Meriç, Niyazi
In this work, a simple method for true coincidence correction is suggested for a voluminous source measured in close detection geometry for a HPGe detector. TrueCoinc program based on Sudár's algorithm was used to determine true coincidence summing correction (TCS) factors by using full energy peak (FEP) efficiency, and total-to-peak (TTP) efficiency curves in which experimental efficiencies are obtained from almost coincident-free radionuclides such as 54Mn, 57Co, 65Zn, 109Cd, 137Cs and 241Am. In order to calculate TTP efficiency curve three different approaches were tested. One of them is new and here called trapezoid approach which was used successfully in determining total count of spectrum for the TTP efficiency curves. According to different TTP determination methods, the changes in true coincidence factors are observed. The FEP efficiency curves are also established for a cylindrical source. Then, TCS factors were determined for the particular peaks of daughters of 226Ra, 238U, and 232Th using the suggested method. Those activities measured from some certified reference materials such as IAEA RGU-1 and RGTh-1 are used to validate the present TCS correction procedure.
Depuration and uptake kinetics of I, Cs, Mn, Zn and Cd by the earthworm (Lumbricus terrestris) in radiotracer-spiked litter
Sheppard, S.C.; Evenden, W.G.; Cornwell, T.C.
The relative depuration and uptake kinetics of contaminants should be known to interpret appropriately the use of organisms such as earthworms in environmental bioassays and monitoring. For example, 14-d earthworm bioassays should be interpreted with the knowledge that some contaminants will continue to accumulate in tissues for months. The radiotracers {sup 125}I, {sup 134}Cs, {sup 54}Mn, {sup 65}Zn, and {sup 109}Cd were applied to deciduous litter and specimens of Lumbricus terrestris were exposed, either to litter alone or to litter on the top of soil columns. Depuration was monitored for 120 d and uptake, in a separate experiment, for 20 d. Both depuration and uptake were described using two-phase, first-order statistical models. Cut clearance had a mean half-time of 1.4 d. The mean half-time for physiological depuration decreased from I (210 d) > Cd (150 d) > Zn (69 d) > Mn (40 d) > Cs (24 d). Both the depuration and the uptake experiments were necessary to resolve even partially the multiphase processes. Earthworm/soil dry weight concentration ratios decreased from Cd > Zn > I {ge} Cs {ge} Mn. The very slow kinetics indicate that tissue concentrations will increase continuously for a long time, with important implications for subsequent food-chain transfers.
The preliminary evaluation of Mn DTPA as a potential contrast agent for nuclear magnetic resonance imaging.
Boudreau, R J; Frick, M P; Levey, R M; Lund, G; Sirr, S A; Loken, M K
The pharmacokinetics of 54Mn administered as Mn-diethylenetriamine pentaacetic acid (DTPA) are being investigated to determine if tissue-specific uptake of manganese could be observed while increasing urinary excretion. This chelation and increased excretion should reduce toxicity. In order to obviate the need for repetitive quantitative nuclear magnetic resonance imaging (NMR) we have substituted tracer amounts of a radioisotope of manganese, Mn-54, for the stable ion. By 6 hours, 58 +/- 7% of the injected dose had been excreted in the urine. Peak liver accumulation occurred within 30 minutes (0.50 +/- 0.14% injected dose/g X kg body weight). The pancreas also showed a relatively high accumulation of tracer (0.25 +/- 0.04%/g X kg body weight), reaching a peak at 4 hours. The pancreas to liver ratios were highest at 6 hours (0.7). There was also a substantial accumulation of the manganese in bile. The blood concentration fell very rapidly with little tracer remaining in the blood at 1 hour. Based on these pharmacokinetics, imaging experiments were conducted before, immediately after, and 9 or 24 hours postinjection. These images showed enhanced kidneys and, later (at 9 hours), an excellent parenchymal-collecting system differentiation. The gallbladder was negatively enhanced. The liver showed either increased or decreased signal strength relative to skeletal muscle depending on the pulse sequence used. We conclude that Mn++, administered as Mn-DTPA, merits further investigation as an NMR contrast agent. PMID:3451753
Radioisotopes Demonstrate the Contrasting Bioaccumulation Capacities of Heavy Metals in Embryonic Stages of Cephalopod Species
Lacoue-Labarthe, Thomas; Villanueva, Roger; Rouleau, Claude; Oberhänsli, François; Teyssié, Jean-Louis; Jeffree, Ross; Bustamante, Paco
Cephalopods play a key role in many marine trophic food webs and also constitute alternative fishery resources in the context of the ongoing decline in finfish stocks. Most coastal cephalopod species of commercial importance migrate into shallow waters during the breeding season to lay their eggs, and are consequently subjected to coastal contamination. Eggs of common cuttlefish Sepia officinalis, European squid Loligo vulgaris, common octopus Octopus vulgaris and the sepiolid Rossia macrosoma were exposed during embryonic development to dissolved 110mAg, 109Cd, 60Co, 54Mn and 65Zn in order to determine their metal accumulation efficiencies and distribution among different egg compartments. Cuttlefish eggs, in which hard shells enclose the embryos, showed the lowest concentration factor (CF) values despite a longer duration of exposure. In contrast, octopus eggs, which are only protected by the chorionic membrane, accumulated the most metal. Uptake appears to be linked to the selective retention properties of the egg envelopes with respect to each element. The study also demonstrated that the octopus embryo accumulated 110mAg directly from the dissolved phase and also indirectly through assimilation of the contaminated yolk. These results raise questions regarding the potential contrasting vulnerability of early life stages of cephalopods to the metallic contamination of coastal waters. PMID:22132123
Decay counting in the age of AMS
NASA Astrophysics Data System (ADS)
Arnold, James R.
Up to the advent of AMS, all the accomplishments of 14C dating, and the studies of 10Be and other long-lived radionuclides, were made by low-level decay counting, the technique pioneered by W.F. Libby. It will hardly be news to people at this conference that, while much was accomplished in the three decades when counting prevailed, the world has now changed decisively. I will try to give an account of where low-level counting was "before the revolution," and of what its usefulness is today. There are still some remarkable examples of its application, the best being the neutrino experiment of Raymond Davis, and its potential successors. Some cosmogenic nuclides, whose half-lives are less than 10 3 yr, are still best measured by decay; this will continue unless the overall ion yield of AMS systems rises markedly from present levels. One long-lived nuclide, 53Mn, is still best measured by neutron activation as 312-day 54Mn, but this may not continue.
Radioactive targets for nuclear astrophysics research at LANSCE
Koehler, P.E.; O'Brien, H.A.; Gursky, J.C.
During the past few years we have made measurements of (n,p) and (n,{alpha}) cross sections on several radioactive nuclei of importance to nuclear astrophysics. The measurements were made at the Manuel Lujan, Jr., Neutron Scattering Center (LANSCE) from thermal neutron energy to approximately 100 keV. Successful measurements have been completed on the radioisotopes {sup 7}Be, {sup 22}Na and {sup 36}Cl while preliminary data have been taken on targets of {sup 54}Mn and {sup 55}Fe. Similar measurements have also been made on the stable isotopes {sup 14}N, {sup 17}O and {sup 35}Cl. We are currently assembling a 4{pi} barium fluoride (BaF{sub 2}) detector which will allow us to expand our program to (n,{gamma}) measurements. The (n,{gamma}) (and in some cases future (n,p)) measurements will require targets with higher specific activity and greater chemical purity than we have so far been able to use. We discuss the fabrication techniques used for the samples produced so far, the requirements the future (n,{gamma}) targets must meet and our current plans for producing them, and the physics motivations for the measurements.
Radionuclide Concentrations in Soils and Vegetation at Low-Level Radioactive Waste Disposal Area G during the 1997 Growing Season
L. Naranjo, Jr.; P. R. Fresquez; R. J. Wechsler
Soil and overstory and understory vegetation (washed and unwashed) collected at eight locations within and around Area G-a low-level radioactive solid-waste disposal facility at Los Alamos National Laboratory-were analyzed for 3H, 238Pu, 239Pu, 137CS, 234U, 235U, 228AC, Be, 214Bi, 60Co, 40& 54Mn, 22Na, 214Pb and 208Tl. In general, most radionuclide concentrations, with the exception of 3Ef and ~9Pu, in soils and overstory and understory vegetation collected from within and around Area G were within upper (95'%) level background concentrations. Although 3H concentrations in vegetation from most sites were significantly higher than background (>2 pCi mL-l), concentrations decreased markedly in comparison to last year's results. The highest `H concentration in vegetation was detected from a juniper tree that was growing over tritium shaft /+150; it contained 530,000 pCi 3H mL-l. Also, as in the pas~ the transuranic waste pad area contained the highest levels of 239Pu in soils and in understory vegetation as compared to other areas at Area G.
Radionuclide concentrations in soils and vegetation at radioactive-waste disposal Area G during the 1996 growing season. Progress report
Fresquez, P.R.; Vold, E.L.; Naranjo, L. Jr.
Soil and overstory and understory vegetation (washed and unwashed) collected at eight locations within and around Area G--a low-level radioactive solid-waste disposal facility at Los Alamos National laboratory--were analyzed for {sup 3}H, {sup 90}Sr, {sup 238}Pu, {sup 239}Pu, {sup 137}Cs, {sup 234}U, {sup 235}U, {sup 238}U, {sup tot}U, {sup 228}Ac, {sup 214}Bi, {sup 60}Co, {sup 40}K, {sup 54}Mn, {sup 22}Na, {sup 214}Pb, and {sup 208}Tl. Also, heavy metals (Ag, As, Ba, Be, Cd, Cr, Hg, Ni, Pb, Sb, Se, and Tl) in soil and vegetation were determined. In general, most radionuclide concentrations, with the exception of {sup 3}H and {sup 239}Pu, in soils and washed and unwashed overstory and understory vegetation collected from within and around Area G were within upper limit background concentrations. Tritium was detected as high as 14,744 pCi mL{sup {minus}1} in understory vegetation collected from transuranic (TRU) waste pad {number_sign}4, and the TRU waste pad area contained the highest levels of {sup 239}Pu in soils and in understory vegetation as compared to other areas at Area G.
Distribution of radionuclides in Dardanelle Reservoir sediments.
Forgy, J R; Epperson, C E; Swindle, D L
Natural and reactor-discharged gamma-ray emitting radionuclides were measured in Dardanelle Reservoir surface sediments taken near the Arkansas Nuclear One Power Plant site. Samples represented several water depths and particle sizes, at 33 locations, in a field survey conducted in early September 1980. Radionuclide contents of dry sediments ranged as follows: natural radioactivity (40K as well as uranium and thorium decay products) 661-1210 Bq/kg; and reactor discharged radioactivity (137Cs, 134Cs, 60Co,, 58Co, 54Mn), no detectable activity to 237 Bq/kg. In general, radionuclide contents were positively correlated with decreasing sediment particle size. The average external whole-body and skin doses from all measurable reactor-discharged radionuclides were calculated according to the mathematical formula for determining external dose from sediment given by the U.S. Nuclear Regulatory Commission (NRC). Inside the discharge embayment near the reactor discharge canal, the doses were 1.7 X 10(-3) mSv/yr to the whole body and 2.0 X 10(-3) mSv/yr to the skin. Outside this area, the doses were 0.15 X 10(-3) and 0.18 X 10(-3) mSv/yr to the whole body and skin, respectively. PMID:6693264
Statistical Properties of Excited Nuclei in the Mass Range 47≤A≤59
NASA Astrophysics Data System (ADS)
Zhuravlev, B. V.; Lychagin, A. A.; Titarenko, N. N.; Demenkov, V. G.; Trykova, V. I.
Level densities and their energy dependences for nuclei in the mass range 47≤A≤59 have been determined from the measurements of neutron evaporation spectra in (p,n) reaction. Neutron spectra from (p,n) reaction on nuclei of 47Ti, 48Ti, 49Ti, 53Cr, 54Cr, 57Fe, 59Co have been measured at proton energies between 7 and 11 MeV. The measurements of neutron spectra were performed by time-of-flight fast neutron spectrometer on the pulsed tandem accelerator EGP-15 of IPPE. The high resolution and stability of time-of-flight spectrometer allowed identify reliably the discrete low-lying levels together with continuum part of neutron spectra. Analyses of the measured data have been carried out in the framework of statistical equilibrium and pre-equilibrium models of nuclear reactions. The calculations are done with use of the exact formalism of the statistical theory as given by Hauser-Feshbach with the generalized superfluid model of nucleus, the back-shifted Fermi-gas model and the composite formula of Gilbert-Cameron for nuclear level density. The nuclear level densities of 47V, 48V, 49V, 53Mn, 54Mn, 57Co, 59Ni and their energy dependences have been determined. The obtained results have been discussed in totality with existing experimental and model systematic data.
Statistical properties of excited nuclei in the mass range 47 ⩽ A ⩽ 59
NASA Astrophysics Data System (ADS)
Zhuravlev, B. V.; Lychagin, A. A.; Titarenko, N. N.; Demenkov, V. G.; Trykova, V. I.
Level densities and their energy dependences for nuclei in the mass range of 47 ≤ A ≤ 59 were determined from the results obtained by measuring neutron-evaporation spectra in respective ( p, n) reactions. The spectra of neutrons originating from the ( p, n) reactions on 47Ti, 48Ti, 49Ti, 53Cr, 54Cr, 57Fe, and 59Co nuclei were measured in the proton-energy range of 7-11 MeV. These measurements were performed with the aid of a fast-neutron spectrometer by the time-of-flight method over the base of the EGP-15 pulsed tandem accelerator installed at the Institute for Physics and Power Engineering (Obninsk, Russia). A high resolution of the spectrometer and its stability in the time of flight made it possible to identify reliably discrete low-lying levels along with the continuum part of neutron spectra. Our measured data were analyzed within the statistical equilibrium and preequilibrium models of nuclear reactions. The respective calculations were performed with the aid of the Hauser-Feshbach formalismof statistical theory supplemented with the generalized model of a superfluid nucleus, the back-shifted Fermi gas model, and the Gilbert-Cameron composite formula for nuclear level densities. Nuclear level densities for 47V, 48V, 49V, 53Mn, 54Mn, 57Co, and 59Ni and their energy dependences were determined. The results are discussed and compared with available experimental data and with recommendations of model-based systematics.
Uncertainties in the Fluence Determination in the Surveillance Samples of VVER-440
NASA Astrophysics Data System (ADS)
Konheiser, Joerg; Grahn, Alexander; Borodkin, Pavel; Borodkin, Gennady
The reactor pressure vessel (RPV) represents one of the most important safety components in a nuclear power plant. Therefore, surveillance specimen (SS) programs for the RPV material exist to deliver a reliable assessment of RPV residual lifetime. This report will present neutron fluence calculations for SS. These calculations were carried out by the codes TRAMO [1] and DORT [2]. This study was accompanied by ex-vessel neutron dosimetry experiments at Kola NPP. The main neutron activation monitoring reactions were 54Fe(n,p)54Mn and 58Ni(n,p)58Co. Good agreement was found between the deterministic and stochastic calculation results and between the calculations and the ex-vessel measurements. The different influences on the monitors were studied. In order to exclude the possible healing effects of the samples due to excessive temperatures, the heat release in the surveillance specimens was determined based on the calculated gamma fluences. Under comparatively realistic conditions, the heat increased by 6 K.
Upgraded Neutron Dosimetry Procedure for VVER-440 Surveilance Specimens
NASA Astrophysics Data System (ADS)
Kochkin, V.; Erak, D.; Zaritsky, S.; Egorov, A.; Makhotin, D.
The control of Reactor Pressure Vessel (RPV) metal during lifetime is one of the basic conditions of the reliable and safe operation of a reactor and NPP as a whole. The substantiation of safe RPV operation is based on Surveillance Specimens (SS) testing results and their transfer to the RPV. Since the reliability of the SS program directly depends on the dosimetry accuracy, one of the most important tasks in the investigation of SS is precision estimation of fast neutron fluence (E > 0.5MeV) for each specimen. The upgraded procedure of neutron fluence evaluation for surveillance specimens of VVER-440/213 reactor has been developed and is presented in this paper. This procedure based on measurements of the 54Mn activity of each of the surveillance specimens and neutron field computations. In contrast to the earlier procedures the new one takes into account correctly all pressure vessel internals, influence of core pattern on the neutron field in SS channel, and dependence of spectral index SI0.5/3.0 on the axial coordinate of surveillance specimens. The upgraded procedure is used for neutron fluence evaluation of VVER-440 surveillance and research programs in RRC "Kurchatov institute".
Drury, J.S.; Baldauf, M.F.; Daniel, E.W.; Fore, C.S.; Uziel, M.S.
Published levels of radioactivity in food crops from 21 countries and 4 island chains of Oceania are listed. The tabulation includes more than 3000 examples of 100 different crops. Data are arranged alphabetically by food crop and geographical origin. The sampling date, nuclide measured, mean radioactivity, range of radioactivities, sample basis, number of samples analyzed, and bibliographic citation are given for each entry, when available. Analyses were reported most frequently for /sup 137/Cs, /sup 40/K, /sup 90/Sr, /sup 226/Ra, /sup 228/Ra, plutonium, uranium, total alpha, and total beta, but a few authors also reported data for /sup 241/Am, /sup 7/Be, /sup 60/Co, /sup 55/Fe, /sup 3/H, /sup 131/I, /sup 54/Mn, /sup 95/Nb, /sup 210/Pb, /sup 210/Po, /sup 106/Ru, /sup 125/Sb, /sup 228/Th, /sup 232/Th, and /sup 95/Zr. Based on the reported data it appears that radioactivity from alpha emitters in food crops is usually low, on the order of 0.1 Bq.g/sup -1/ (wet weight) or less. Reported values of beta radiation in a given crop generally appear to be several orders of magnitude greater than those of alpha emitters. The most striking aspect of the data is the great range of radioactivity reported for a given nuclide in similar food crops with different geographical origins.
Instrument for precision long-term β-decay rate measurements
Ware, M. J. Bergeson, S. D.; Ellsworth, J. E.; Groesbeck, M.; Hansen, J. E.; Pace, D.; Peatross, J.
We describe an experimental setup for making precision measurements of relative β-decay rates of {sup 22}Na, {sup 36}Cl, {sup 54}Mn, {sup 60}Co, {sup 90}Sr, {sup 133}Ba, {sup 137}Cs, {sup 152}Eu, and {sup 154}Eu. The radioactive samples are mounted in two automated sample changers that sequentially position the samples with high spatial precision in front of sets of detectors. The set of detectors for one sample changer consists of four Geiger-Müller (GM) tubes and the other set of detectors consists of two NaI scintillators. The statistical uncertainty in the count rate is few times 0.01% per day for the GM detectors and about 0.01% per hour on the NaI detectors. The sample changers, detectors, and associated electronics are housed in a sealed chamber held at constant absolute pressure, humidity, and temperature to isolate the experiment from environmental variations. The apparatus is designed to accumulate statistics over many years in a regulated environment to test recent claims of small annual variations in the decay rates. We demonstrate that absent this environmental regulation, uncontrolled natural atmospheric pressure variations at our location would imprint an annual signal of 0.1% on the Geiger-Müller count rate. However, neither natural pressure variations nor plausible indoor room temperature variations cause a discernible influence on our NaI scintillator detector count rate.
Instrument for precision long-term β-decay rate measurements
NASA Astrophysics Data System (ADS)
Ware, M. J.; Bergeson, S. D.; Ellsworth, J. E.; Groesbeck, M.; Hansen, J. E.; Pace, D.; Peatross, J.
We describe an experimental setup for making precision measurements of relative β-decay rates of 22Na, 36Cl, 54Mn, 60Co, 90Sr, 133Ba, 137Cs, 152Eu, and 154Eu. The radioactive samples are mounted in two automated sample changers that sequentially position the samples with high spatial precision in front of sets of detectors. The set of detectors for one sample changer consists of four Geiger-Müller (GM) tubes and the other set of detectors consists of two NaI scintillators. The statistical uncertainty in the count rate is few times 0.01% per day for the GM detectors and about 0.01% per hour on the NaI detectors. The sample changers, detectors, and associated electronics are housed in a sealed chamber held at constant absolute pressure, humidity, and temperature to isolate the experiment from environmental variations. The apparatus is designed to accumulate statistics over many years in a regulated environment to test recent claims of small annual variations in the decay rates. We demonstrate that absent this environmental regulation, uncontrolled natural atmospheric pressure variations at our location would imprint an annual signal of 0.1% on the Geiger-Müller count rate. However, neither natural pressure variations nor plausible indoor room temperature variations cause a discernible influence on our NaI scintillator detector count rate.
Determination of manganese-53 by neutron activation and other miscellaneous studies on lunar dust.
Herr, W; Herpers, U; Hess, B; Skerra, B; Woelfle, R
A highly sensitive determination of spallogenic (53)Mn (T = 2 x 106 yr) was accomplished in 0.99 g of lunar soil. The chemical yield of Mn is determined with "carrier-free" (52)Mn tracer. During a 23-day reactor irradiation the (53)Mn is transformed into (54)Mn (T = 300 days). Appropriate chemical recycling was done by ion exchange and distillation. Interferences of the (n,p) and the (n,2n) nuclear reactions were carefully studied. A (53)Mn disintegration rate of 30.3 +/- 5.5 dpm/kg results. This extremely economic method is proposed for further detailed lunar profile measurements. The Re content, which is of possible cosmochemical interest, was determined to be 11 ppb. Appropriate separation techniques were used. The rather weak and complex thermoluminescence properties made a more basic study advisable. Thermogravimetric analysis, mass spectroscopy, and Moessbauer spectroscopy were applied. The presence of ilmenite, metallic Fe etc., and of an unidentified Fe(2+)-containing compound was deduced. Natural thermoluminescence could not be proved with certainty in our surface sample. However, the complexity of the artificial thermoluminescence demands better defined mineral fractions. The fission track method was used to measure U distribution in glass spherules etc. PMID:17781575
Incident shock-wave characteristics in air, argon, carbon dioxide, and helium in a shock tube with unheated helium driver
NASA Technical Reports Server (NTRS)
Miller, C. G., III; Jones, J. J.
Incident shock-wave velocities were measured in the Langley 6-inch expansion tube, operated as a shock tube, with air, argon, carbon dioxide, and helium as test gases. Unheated helium was used as the driver gas and most data were obtained at pressures of approximately 34 and 54 MN/sq m. A range of pressure ratio across the diaphragm was obtained by varying the quiescent test-gas pressure, for a given driver pressure, from 0.0276 to 34.5 kN/sq m. Single- and double-diaphragm modes of operation were employed and diaphragms of various materials tested. Shock velocity was determined from microwave interferometer measurements, response of pressure transducers positioned along interferometer measurements, response of pressure transducers positioned along the driven section (time-of-arrival gages), and to a lesser extent, measured tube-wall pressure. Velocities obtained from these methods are compared and limitations of the methods discussed. The present results are compared with theory and the effects of diaphragm mode (single or double diaphragm), diaphragm material, heating of the driver gas upon pressurization of the driver section, diaphragm opening time, interface mixing, and two-dimensional (nonplanar) flow are discussed.
Tritium concentrations in bees and honey at Los Alamos National Laboratory
Fresquez, P.R.; Armstrong, D.R.; Salazar, J.G.
Los Alamos National Laboratory (LANL) has maintained a network of honey bee colonies at LANL, perimeter (Los Alamos townsite and White Rock/Pajarito Acres) and regional (background) areas for over 15 years; the main objective of this honey bee network was to help determine the bioavailability of certain radionuclides in the environment. Of all the radionuclides studied ({sup 3}H, {sup 57}Co, {sup 7}Be, {sup 22}Na, {sup 54}Mn, {sup 83}Rb, {sup 137}Cs, {sup 238}Pu, {sup 239}Pu, {sup 90}Sr and total U), tritium was consistently detected in bees and was most readily transferred to the honey. In fact, honey collected from hives located at TA-21, TA-33, TA-50, TA-53, and TA-54 and from White Rock/Pajarito Acres contained significantly higher concentrations of {sup 3}H than regional background hives. Based on the average concentration of all radionuclides measured over the years, the effective dose equivalent (EDE) from consuming 5 kg (11 lb) of honey collected from Los Alamos (townsite) and White Rock/Pajarito Acres, after regional background has been subtracted, was 0.0186 ({+-}0.0507) and 0.0016 ({+-}0.0010) mrem/yr, respectively. The highest EDE, based on the mean + 2SD (95% confidence level), was 0.1200 mrem/y; this was <0.2% of the International Commission on Radiological Protection permissible dose limit of 100 mrem/yr from all pathways.
Monte carlo simulation of in situ gamma-spectra recorded by NaI (Tl) detector in the marine environment
NASA Astrophysics Data System (ADS)
Wang, Yiming; Zhang, Yingying; Wu, Ning; Wu, Bingwei; Liu, Yan; Cao, Xuan; Wang, Qian
To develop a NaI (Tl) detector for in situ radioactivity monitoring in the marine environment and enhance the confidence of the probability of the gamma-spectrum analysis, Monte Carlo simulations using the Monte Carlo N-Particle ( MNCP ) code were performed to provide the response spectra of some interested radionuclides and the background spectra originating from the natural radionuclides in seawater recorded by a NaI (Tl) detector. A newly developed 75 mm × 75 mm NaI (Tl) detector was calibrated using four reference radioactive sources 137Cs, 60Co, 40K and 54Mn in the laboratory before the field measurements in seawater. A simulation model was established for the detector immersed in seawater. The simulated spectra were all broadened with Gaussian pulses to reflect the statistical fluctuations and electrical noise in the real measurement. The simulated spectra show that the single-energy photons into the detector are mostly scattering low-energy photons and the high background in the low energy region mainly originates from the Compton effect of the high energy ?-rays of natural radionuclides in seawater. The simulated background spectrum was compared with the experimental one recorded in field measurement and they seem to be in good agreement. The simulation method and spectra can be used for the accurate analysis of the filed measurement results of low concentration radioactivity in seawater.
TORT/MCNP coupling method for the calculation of neutron flux around a core of BWR.
Kurosawa, Masahiko
For the analysis of BWR neutronics performance, accurate data are required for neutron flux distribution over the In-Reactor Pressure Vessel equipments taking into account the detailed geometrical arrangement. The TORT code can calculate neutron flux around a core of BWR in a three-dimensional geometry model, but has difficulties in fine geometrical modelling and lacks huge computer resource. On the other hand, the MCNP code enables the calculation of the neutron flux with a detailed geometry model, but requires very long sampling time to give enough number of particles. Therefore, a TORT/MCNP coupling method has been developed to eliminate the two problems mentioned above in each code. In this method, the TORT code calculates angular flux distribution on the core surface and the MCNP code calculates neutron spectrum at the points of interest using the flux distribution. The coupling method will be used as the DOT-DOMINO-MORSE code system. This TORT/MCNP coupling method was applied to calculate the neutron flux at points where induced radioactivity data were measured for 54Mn and 60Co and the radioactivity calculations based on the neutron flux obtained from the above method were compared with the measured data. PMID:16604689
Trophic transfer of radioisotopes in Mediterranean sponges through bacteria consumption.
Lacoue-Labarthe, Thomas; Warnau, Michel; Beaugeard, Laureen; Pascal, Pierre-Yves
Numerous field studies highlighted the capacities of marine sponges to bioaccumulate trace elements and assessed their potential as biomonitors of the marine environment. Experimental works demonstrated that dissolved metals and radionuclides can be taken up directly by sponge tissues but, to the best of our knowledge, little is known on the contribution of the dietary pathway through the consumption of contaminated bacteria considered as one of the trophic source in sponge diet. Objectives of this work are to study trophic transfer of radiotracers (110m)Ag, (241)Am, (109)Cd, (57)Co, (134)Cs, (54)Mn and (65)Zn from the marine bacteria Pseudomonas stutzeri to the Mediterranean sponges Aplysina cavernicola and Ircinia oros. P. stutzeri efficiently bioaccumulated trace elements in our culture experimental conditions with CF comprised between 10(5) and 10(7) after 48 h of growth in radiolabeled medium. When fed with these radiolabelled bacteria, A. cavernicola took up around 60% of radiotracers accumulated in trophic source except (134)Cs for which only 8% has been transferred from bacteria to sponge. Contrasting to this, I. oros retained only 7% of (110m)Ag, (109)Cd and (65)Zn counted in bacteria, but retained 2-fold longer accumulated metals in its tissues. The sponge inter-specific differences of accumulation and depuration following a trophic exposure are discussed with respect to the structure and the clearance capacities of each species. PMID:26544727
Preliminary Assessment of the Nuclide Migration from the Activation Zone Around the Proposed Spallation Neutron Source Facility
Dole, L.R.
The purpose of this study is to investigate the potential impacts of migrating radionuclides from the activation zone around the proposed Spallation Neutron Source (SNS). Using conservatively high estimates of the potential inventory of radioactive activation products that could form in the proposed compacted-soil shield berm around an SNS facility on the Oak Ridge Reservation (ORR), a conservative, simplified transport model was used to estimate the potential worst-case concentrations of the 12 long-lived isotopes in the groundwater under a site with the hydrologic characteristics of the ORR. Of the 12, only 3 isotopes showed any potential to exceed the U.S. Nuclear Regulatory Commission (NRC) 10 Code of Federal Regulations (CFR) Part 20 Drinking Water Limits (DWLs). These isotopes were 14C, 22Na, and 54Mn. The latter two activation products have very short half-lives of 2.6 years and 0.854 year, respectively. Therefore, these will decay before reaching an off-site receptor, and they cannot pose off-site hazards. However, for this extremely conservative model, which overestimates the mobility of the contaminant, 14C, which has a 5,730-year half-life, was shown to represent a potential concern in the context of this study's conservative assumptions. This study examines alternative modifications to the SNS shield berm and makes recommendations.
Geomicrobial transformation of manganese in Gorda Ridge event plumes
NASA Astrophysics Data System (ADS)
Cowen, James P.; Bertram, Miriam A.; Baker, Edward T.; Feely, Richard A.; Massoth, Gary J.; Summit, Melanie
Event plumes form as episodic discharges of large volumes of hydrothermal solutions in response to magmatic diking/eruptive events. In consequence, event plumes represent the sudden injection of exploitable reduced chemical substrates, as well as inhibitory constituents, and likely induce successional changes in the microbial community structure and activity within event plume waters. In response to a major seismic event detected beginning 28 February 1996 at the northern Gorda Ridge, a series of three rapid response and follow-up cruises (GREAT 1, 2 and 3) were mounted over a period of three months. This report focuses on time-series measurements of manganese geomicrobial parameters in the two event plumes found in association with this seismic event. Scanning transmission electron microscopy, elemental microanalysis, and radioisotope ( 54Mn) uptake experiments were employed on samples collected from vertical and tow-yo casts from the three cruises. Numbers of bacteria and ratios of metal precipitating capsuled bacteria to total bacteria were greatest in the youngest (days old) plume, EP96A, found during GREAT 1; however, when normalized to the hydrothermal temperature anomaly, the greatest values were found in a second event plume, EP96B, discovered during GREAT 2 (up to 1 month old). Early capsule bacteria and particulate Mn distributions may have been influenced by entrainment of resuspended sediment, while those of the oldest (2-3 months) plume sample may have been subjected to preferential aggregation and particle settling.
Bioavailability of zinc, copper, and manganese from infant diets
Bell, J.G.
A series of trace element absorption experiments were performed using the Sprague-Dawley suckling rat put and infant rhesis monkey (Macaca mulatta) with extrinsic radiolabeling to assess the bioavailability of Zn, Cu, and Mn from infant diets and to examine specific factors that affect absorption of these essential nutrients. Bioavailability of Cu as assessed by 6 h liver uptake (% of /sup 64/Cu dose) was highest from human milk and cow milk based formula and significantly lower from cow milk and soy based formula. Copper bioavailability from infant cereal products as assessed by whole body uptake (% of /sup 64/Cu dose) in d 20 rats, 9 h postintubation, was low compared to the bioavailability from cow milk or human milk alone. /sup 65/Zn uptake in d 20 rats, 9 h postintubation, was significantly lower from cereals fed alone or in combination with cow or human milk as compared to the uptake from the milks fed alone. Zn bioavailability varied among cereal diets, (lowest from cereals containing phytate and highest from cereal/fruit products). Mn bioavailability from infant diets was assessed using a modified suckling rat pup model. Bioavailability (24 h whole body retention of /sup 54/Mn) was high from all milks and commercial formulas tested.
The EWGRD Round Robin Measurement Exercise
NASA Astrophysics Data System (ADS)
Thornton, D. A.; Wagemans, J.; Fernandes, A. C.; Girard, J. M.; Kis, D. P.; Klupák, V.; Mutnuru, R.; Philibert, H.; Rousseau, G.; Santos, J. P.; Serén, T.; Zsolnay, E. M.
This paper presents the results of a round robin exercise carried out to compare specific activity measurements performed by eight European organisations on a set of ten neutron activation detectors containing the radio-nuclides 110mAg, 60Co, 54Mn, 46Sc and 94Nb. The purpose of the exercise was to demonstrate the level of consistency between the participating organisations in blind tests of measurements relevant to reactor metrology. The samples used were selected from a stock of pre-existing irradiated material held at SCK•CEN. Taking turns over a period of approximately 9 months, the participating organisations received the samples, measured them and provided their results to an independent referee who collated and compared the data. The inter-comparison has demonstrated good agreement between the participants with standard deviations for each dosimeter varying between 1.6% and 3.1%. The paper provides results of the EWGRD Round Robin in an anonymised form together with discussion and conclusions which may be drawn from the exercise.
Numerical Model for Cosmic Rays Species Production and Propagation in the Galaxy
NASA Technical Reports Server (NTRS)
Farahat, Ashraf; Zhang, Ming; Rassoul, Hamid; Connell, J. J.
In recent years, considerable progress has been made in studying the propagation and origin of cosmic rays, as new and more accurate data have become available. Many models have been developed to study cosmic ray interactions and propagation showed flexibility in resembling various astrophysical conditions and good agreement with observational data. However, some astrophysical problems cannot be addressed using these models, such as the stochastic nature of the cosmic rays source, small-scale structures and inhomogeneities in the interstellar gas that can affect radioactive secondary abundance in cosmic rays. We have developed a new model and a corresponding computer code that can address some of these limitations. The model depends on the expansion of the backward stochastic solution of the general diffusion transport equation (Zhang 1999) starting from an observer position to solve a group of diffusion transport equations each of which represents a particular element or isotope of cosmic ray nuclei. In this paper we are focusing on key abundance ratios such as B/C, sub-Fe/Fe, (10)Be/(9)Be, (26)Al/(27)Al, (36)Cl/(37)Cl and (54)Mn/(55)Mn, which all have well established cross sections, to evaluate our model. The effect of inhomogeneity in the interstellar medium is investigated. The contribution of certain cosmic ray nuclei to the production of other nuclei is addressed. The contribution of various galactic locations to the production of cosmic ray nuclei observed at solar system is also investigated.
Diffusion of chromium and manganese in γ-TiAl
NASA Astrophysics Data System (ADS)
Prasad Tiwari, Gyanendra; Iijima, Yoshiaki; Lee, Chan-Gyu; Koo, Bon-Heun
The γ-TiAl intermetallic compound with suitable alloying additions has shown considerable promise as a material for high-temperature applications. Diffusion studies in this alloy system are useful in assessment of their creep behaviour and structural stability in service conditions. Tracer diffusion coefficients of 51Cr and 54Mn in a γ-TiAl intermetallic compound containing 54.1 at. % aluminium were determined in the temperature range from 1095 to 1470 K. The temperature dependence of both the diffusing species follows a linear Arrhenius behaviour and can be expressed as D Cr = 4.4 × 10-3exp(-350 kJ mol-1/RT) m2 s-1 and D Mn = 1.2 × 10-3 ×exp(-326 kJ mol-1/RT) m2 s-1. The data are analysed on the basis of empirical correlations between the diffusion and melting parameters applicable for conventional mono-vacancy diffusion mechanism in metals. It is concluded that impurity diffusion in γ-TiAl occurs through the migration of thermal vacancies via nearest-neighbour or next-nearest neighbour jumps.
Leaching of accelerator-produced radionuclides
Baker, S.; Bull, J.; Goss, D.
Leaching of radionuclides produced in soil and rock by high energy proton-induced radiation was studied for the SCC and CEBAF sites. Comparison was made with predictions of a Monte-Carlo code CASIM and previous results for the Fermilab site. The principal long-lived radionuclides were {sup 3}H and {sup 22}Na in agreement with Fermilab results. A few other radionuclides were present at lower concentrations in a subset of the samples. For example, {sup 134}Cs was detected in a few SSC water samples and {sup 7}Be and {sup 54}Mn were present at higher concentrations in a CEBAF sample. Leaching from SSC chalk was dependent on previous weathering and on leaching time. The more soil-like marl and shale were leached more rapidly. Results of this study in conjunction with the SSC ground-water model show that adequate ground-water protection would result for loss of the entire proton beam in the SSC Collider tunnel.
Heavy Neutrino Emission in Nuclear Beta Decay Spectra
NASA Astrophysics Data System (ADS)
Hime, Andrew
Available from UMI in association with The British Library. Requires signed TDF. A modest spectrometer has been constructed and employed in measurements of electron energy spectra from the beta decay of ^ {35}S and ^{63} Ni. In both cases studied the data exhibit a threshold distortion 17 keV below the endpoint which is well described by the hypothesis that the electron neutrino couples to a heavy mass eigenstate. In terms of a two state mixing scheme and after radiative corrections, the ^ {35}S data indicate an M_2 = 16.95 +/- 0.35 keV component coupling with a mixing probability of sin^2 theta = 0.0078 +/- 0.0008. Data from a ^{63}Ni measurement yield a similar result with M_2 = 16.75 +/- 0.38 keV and sin ^2theta = 0.0101 +/- 0.0021. The errors quoted include both statistical and systematic contributions where systematic effects arise, predominantly, through small uncertainties in the electron response function. The electron response function has been measured from internal conversion electrons following electron capture, details of which are described. These results agree with earlier observations in the beta^ectra of ^3 H and ^{35}S as well as more recent studies of the ^{14 }C spectrum. On the other hand, experiments employing magnetic spectrometers provide no such evidence for heavy neutrino emission in nuclear beta decay. While this leaves the experimental situation unsettled some thoughts are provided on possible shortcomings of these experiments. In addition, a discussion is given on the possibility of alternative descriptions of the data providing positive evidence for the 17-keV neutrino as well as to how the experimental situation might be improved in the future. A technique is proposed which can serve to resolve the issue both with respect to experiments employing solid state detectors as well as those using magnetic spectrometers. If the interpretation of the anomalies observed in beta spectra is correct then we have our first glimpse that neutrinos
Development of Novel Electrode Materials for the Electrocatalysis of Oxygen-Transfer and Hydrogen-Transfer Reactions
Brett Kimball Simpson
Throughout this thesis, the fundamental aspects involved in the electrocatalysis of anodic O-transfer reactions and cathodic H-transfer reactions have been studied. The investigation into anodic O-transfer reactions at undoped and Fe(III)[doped MnO{sub 2} films] revealed that MnO{sub 2} film electrodes prepared by a cycling voltammetry deposition show improved response for DMSO oxidation at the film electrodes vs. the Au substrate. Doping of the MnO{sub 2} films with Fe(III) further enhanced electrode activity. Reasons for this increase are believed to involve the adsorption of DMSO by the Fe(III) sites. The investigation into anodic O-transfer reactions at undoped and Fe(III)-doped RuO{sub 2} films showed that the Fe(III)-doped RuO{sub 2}-film electrodes are applicable for anodic detection of sulfur compounds. The Fe(III) sites in the Fe-RuO{sub 2} films are speculated to act as adsorption sites for the sulfur species while the Ru(IV) sites function for anodic discharge of H{sub 2}O to generate the adsorbed OH species. The investigation into cathodic H-transfer reactions, specifically nitrate reduction, at various pure metals and their alloys demonstrated that the incorporation of metals into alloy materials can create a material that exhibits bifunctional properties for the various steps involved in the overall nitrate reduction reaction. The Sb{sub 10}Sn{sub 20}Ti{sub 70}, Cu{sub 63}Ni{sub 37} and Cu{sub 25}Ni{sub 75} alloy electrodes exhibited improved activity for nitrate reduction as compared to their pure component metals. The Cu{sub 63}Ni{sub 37} alloy displayed the highest activity for nitrate reduction. The final investigation was a detailed study of the electrocatalytic activity of cathodic H-transfer reactions (nitrate reduction) at various compositions of Cu-Ni alloy electrodes. Voltammetric response for NO{sub 3}{sup -} at the Cu-Ni alloy electrode is superior to the response at the pure Cu and Ni electrodes. This is explained on the basis of the
Soluble iron modulates iron oxide particle-induced inflammatory responses via prostaglandin E2 synthesis: In vitro and in vivo studies
Background Ambient particulate matter (PM)-associated metals have been shown to play an important role in cardiopulmonary health outcomes. To study the modulation of PM-induced inflammation by leached off metals, we investigated intracellular solubility of radio-labeled iron oxide (59Fe2O3) particles of 0.5 and 1.5 μm geometric mean diameter. Fe2O3 particles were examined for the induction of the release of interleukin 6 (IL-6) as pro-inflammatory and prostaglandin E2 (PGE2) as anti-inflammatory markers in cultured alveolar macrophages (AM) from Wistar Kyoto (WKY) rats. In addition, we exposed male WKY rats to monodispersed Fe2O3 particles by intratracheal instillation (1.3 or 4.0 mg/kg body weight) to examine in vivo inflammation. Results Particles of both sizes are insoluble extracellularly in the media but moderately soluble in AM with an intracellular dissolution rate of 0.0037 ± 0.0014 d-1 for 0.5 μm and 0.0016 ± 0.0012 d-1 for 1.5 μm 59Fe2O3 particles. AM exposed in vitro to 1.5 μm particles (10 μg/mL) for 24 h increased IL-6 release (1.8-fold; p < 0.05) and also PGE2 synthesis (1.9-fold; p < 0.01). By contrast, 0.5 μm particles did not enhance IL-6 release but strongly increased PGE2 synthesis (2.5-fold, p < 0.005). Inhibition of PGE2 synthesis by indomethacin caused a pro-inflammatory phenotype as noted by increased IL-6 release from AM exposed to 0.5 μm particles (up to 3-fold; p < 0.005). In the rat lungs, 1.5 but not 0.5 μm particles (4.0 mg/kg) induced neutrophil influx and increased vascular permeability. Conclusions Fe2O3 particle-induced neutrophilic inflammatory response in vivo and pro-inflammatory cytokine release in vitro might be modulated by intracellular soluble iron via PGE2 synthesis. The suppressive effect of intracellular released soluble iron on particle-induced inflammation has implications on how ambient PM-associated but soluble metals influence pulmonary toxicity of ambient PM. PMID:20028532
Influence of iron on cylindrocarpon root rot development on ginseng.
Rahman, Mahfuzur; Punja, Zamir K
ABSTRACT Cylindrocarpon root rot, caused by Cylindrocarpon destructans, is an important disease on ginseng (Panax quinquefolius) in Canada. We studied the effects of iron (Fe) on disease severity and pathogen growth. When Hoagland's solution was amended with Fe at 56 and 112 mug/ml compared with 0 mug/ml, disease initiation and final severity on hydroponically maintained ginseng roots was significantly (P<0.0001) enhanced. Under field conditions, wounding of roots with a fine needle followed by application of 0.05% FeNaEDTA to the rhizosphere of treated plants significantly enhanced Cylindrocarpon root rot in 2003 and 2004 compared with unwounded roots with Fe or wounded roots without Fe. Foliar applications of Fe (as FeNaEDTA) to ginseng plants three times during the 2002 and 2003 growing seasons significantly increased Fe levels in root tissues. These roots developed larger lesions following inoculation with C. destructans in vitro. When radioactive Fe ((59)Fe) was applied to the foliage of ginseng plants, it was detected in the secondary phloem and in cortical and epidermal tissues within 1 week. Artificially wounded areas on the roots accumulated more (59)Fe than healthy areas. Diseased tissue also had threefold higher levels of phenolic compounds and Fe compared with adjoining healthy tissues. High-performance liquid chromatography analysis revealed enhanced levels of protocatechuic acid, chlorogenic acid, caffeic acid, ferulic acid, cinnamic acid, phloridizin, and quercetin. Phenolic compounds produced in diseased and wounded tissues sequestered Fe in vitro. The effects of Fe on mycelial growth, conidial germ tube length, and secondary branching of germ tubes of C. destructans were examined in vitro. When grown on Chrome-azurol S medium, Fe also was sequestered by C. destructans through siderophore production, which was visualized as a clearing pigmented zone at the margin of colonies. Mycelial dry weight was significantly increased in glucose/ yeast broth
Experimental incineration of low level radioactive samples.
Yumoto, Y; Hanafusa, T; Nagamatsu, T; Okada, S
To determine the volume reduction potential for incineration of radioactivity in low-level radioactive waste, an incineration experiment was performed at the Okayama University Radioisotope Center (OURIC). Solid low-level radioactive samples (LLRS) were prepared for 15 routinely used radionuclides (45Ca, 1251, 32p, 33p, 35S, 59Fe, 123I, 131I, 67Ga, 99mTc, 111In, 3H, 14C, 51Cr, and 201Tl). For each radionuclide, incinerated one at a time, the smoke duct radioisotope concentration was less than 1/10 of the regulatory concentration limit (The Japanese law concerning prevention of radiation hazard due to radioisotopes, etc.). The radionuclide-containing combustible and semi-combustible LLRS were incinerated at the AP-1 50R furnace erected at OURIC, and the distribution of radioactivity inside and outside the furnace was measured. In the experimental incineration of LLRS containing these 15 radionuclides, the fractions released (RF) in the gas phase of the final smoke duct ranged from 0.165 to 0.99. The radioactivities remaining in the incineration residue were 99mTc, 87%; 59Fe, 83.1%; 45Ca, 75%; 51Cr, 62.1%; 33P, 62.0%; 32P, 61.1%; 67Ga, 57.7%; 35S, 26.0%; 111In, 21.1%; 201Tl, 16.6%; 123I, 11.9%; 131I, 8.2%; 125I, 2.4%; 14C, 0.39%; 3H, 0.04%. In the incineration of LLR S containing 35S, the rate of adhesion to the furnace wall was lower at high-temperature (809 degrees C) incineration than at low-temperature (376 degrees C) incineration. For LLRS containing one of the three radioiodines, 123I, 125I, or 131I, no such difference was observed between low (372 degrees C) and high (827 degrees C) temperature incineration (RF varied from 0.82 to 0.94). PMID:10910400
Hereditary sideroblastic anemia and glucose-6-phosphate dehydrogenase deficiency in a negro family
Prasad, Ananda S.; Tranchida, Liborio; Konno, Edward T.; Berman, Lawrence; Albert, Samuel; Sing, Charles F.; Brewer, George J.
Detailed clinical and genetic studies have been performed in a Negro family, which segregated for sex-linked sideroblastic anemia and glucose-6-phosphate dehydrogenase (G-6-DP) deficiency. This is the first such pedigree reported. Males affected with sideroblastic anemia had growth retardation, hypochromic microcytic anemia, elevated serum iron, decreased unsaturated iron-binding capacity, increased 59Fe clearance, low 59Fe incorporation into erythrocytes, normal erythrocyte survival (51Cr), normal hemoglobin electrophoretic pattern, erythroblastic hyperplasia of marrow with increased iron, and marked increase in marrow sideroblasts, particularly ringed sideroblasts. Perinuclear deposition of ferric aggregates was demonstrated to be intramitochondrial by electron microscopy. Female carriers of the sideroblastic gene were normal but exhibited a dimorphic population of erythrocytes including normocytic and microcytic cells. The bone marrow studies in the female (mother) showed ringed marrow sideroblasts. Studies of G-6-PD involved the methemoglobin elution test for G-6-PD activity of individual erythrocytes, quantitative G-6-PD assay, and electrophoresis. In the pedigree, linkage information was obtained from a doubly heterozygous woman, four of her sons, and five of her daughters. Three sons were doubly affected, and one was normal. One daughter appeared to be a recombinant. The genes appeared to be linked in the coupling phase in the mother. The maximum likelihood estimate of the recombination value was 0.14. By means of Price-Jones curves, the microcytic red cells in peripheral blood were quantitated in female carriers. The sideroblast count in the bone marrow in the mother corresponded closely to the percentage of microcytic cells in peripheral blood. This is the second example in which the cellular expression of a sex-linked trait has been documented in the human red cells, the first one being G-6-PD deficiency. The coexistence of the two genes in doubly
Binding and accumulation of hemin in Porphyromonas gingivalis are induced by hemin.
Genco, C A; Odusanya, B M; Brown, G
Although hemin is an essential nutrient for the black-pigmented oral bacterium Porphyromonas gingivalis, the mechanisms involved in hemin binding and uptake are poorly defined. In this study, we have examined the binding of hemin and Congo red (CR) to P. gingivalis whole cells and have defined the conditions for maximal binding. Additionally, the accumulation of hemin by P. gingivalis under growing conditions has been characterized. P. gingivalis A7436 was grown under hemin- or iron-deplete conditions (basal medium [BM] or Schaedler broth with dipyridyl [SBD]) or under hemin- or iron-replete conditions (BM with hemin [BMH] or Schaedler broth [SB]), and hemin and CR binding were assessed spectrophotometrically. Binding of hemin by P. gingivalis whole cells was rapid and was observed in samples obtained from cells grown under hemin- and iron-replete and hemin-deplete conditions but was not observed in cells grown under iron limitation. We also found that P. gingivalis whole cells bound more hemin when grown in BMH or SB than cells grown in BM or SBD. Binding of CR by P. gingivalis A7436 was also enhanced when cells were grown in the presence of hemin or when cells were incubated with hemin prior to CR binding. Hemin binding and accumulation were also assessed using [14C]hemin and [59Fe]hemin under growing conditions. Both [14C]hemin and [59Fe]hemin were accumulated by P. gingivalis, indicating that iron and the porphyrin ring were taken into the cell. Binding and accumulation of hemin under growing conditions were also induced by growth of P. gingivalis in hemin-replete media. Hemin accumulation was inhibited by the addition of KCN to P. gingivalis cultures, indicating that active transport was required for hemin uptake. [14C]hemin binding and accumulation were also inhibited by the addition of either cold hemin or protoporphyrin IX. Taken together, these results indicate that P. gingivalis transports the entire hemin moiety into the cell and that the binding and
Deuteron Induced ( d,p) and ( d,2p) Nuclear Reactions up to 50 MeV
NASA Astrophysics Data System (ADS)
Yiğit, M.; Tel, E.; Kara, A.
Many studies have shown that the nuclear reactions of charged particles with nuclei are very important in many fields of nuclear physics. The interactions of deuterons with nuclei have been especially the subject of common research in the history of nuclear physics. Moreover, the knowledge of cross section for deuteron-nucleus interactions are required for various application such as space applications, accelerator driven sub-critical systems, nuclear medicine, nuclear fission reactors and controlled thermonuclear fusion reactors. Particularly, the future of controlled thermonuclear fusion reactors is largely dependent on the nuclear reaction cross section data and the selection of structural fusion materials. Finally, the reaction cross section data of deuteron induced reactions on fusion structural materials are of great importance for development and design of both experimental and commercial fusion devices. In this work, reaction model calculations of the cross sections of deuteron induced reactions on structural fusion materials such as Al ( Aluminium), Ti ( Titanium), Cu ( Copper), Ni ( Nickel), Co ( Cobalt), Fe ( Iron), Zr ( Zirconium), Hf ( Hafnium) and Ta ( Tantalum) have been investigated. The new calculations on the excitation functions of 27 Al( d,2p) 27 Mg, 47 Ti( d,2p) 47 Sc, 65 Cu( d,2p) 65 Ni, 58 Ni( d,2p) 58 Co, 59 Co( d,2p) 59 Fe, 58 Fe( d,p) 59 Fe, 96 Zr( d,p) 97 Zr, 180 Hf ( d,p) 181 Hf and 181 Ta( d,p) 182 Ta have been carried out for incident deuteron energies up to 50 MeV. In these calculations, the equilibrium and pre-equilibrium effects for ( d,p) and ( d,2p) reactions have been investigated. The equilibrium effects are calculated according to the Weisskopf-Ewing ( WE) Model. The pre-equilibrium calculations involve the new evaluated the Geometry Dependent Hybrid Model ( GDH) and Hybrid Model. In the calculations the program code ALICE/ASH was used. The calculated results are discussed and compared with the experimental data taken from the
Direct coupling of packed column supercritical fluid chromatography to continuous corona discharge ion mobility spectrometry.
Rahmanian, A; Ghaziaskar, H S; Khayamian, T
In this study, packed column supercritical fluid chromatography (SFC) was directly coupled to a continuous corona discharge (CD) ion mobility spectrometer (IMS) with several modifications. The main advantage of the developed detector is its capability to introduce full column effluent up to 2000 mL min(-1) CO(2) gas directly into the IMS cell relative to 40 mL min(-1) CO(2) gas as a maximum tolerance, reported for the previous IMS detectors. This achievement was made possible because of using corona discharge instead of (63)Ni as an ionization source and locating the inlet and outlet of the CO(2) gas in the counter electrode of the CD in opposite direction. In addition, a heated interface was placed between back pressure regulator (BPR) and the IMS cell to heat the output of the BPR for introducing sample as the gas phase into the IMS cell. Furthermore, a make-up methanol flow was introduced between the column outlet and BPR to provide a more uniform flow through the BPR and also to prevent freezing and deposition of the analytes in the BPR. The performance of the SFC-CD-IMS was evaluated by analysis of testosterone, medroxyprogesterone, caffeine, and theophylline as test compounds and figures of merit for these compounds have been calculated. PMID:23261285
Role of nickel in membrane-bound hydrogenase and nickel metabolism in Rhizobium japonicum
Stults, L.W.
The membrane-bound hydrogenase of Rhizobium japonicum requires nickel for activity. Radioactive /sup 63/Ni co-migrates with hydrogenase activity in native gel systems and co-elutes with purified hydrogenase form an affinity matrix column. A simplified scheme for the purification of hydrogenase has been developed and constitutes the first report of the aerobic purification of this enzyme from R. japonicum. The aerobic purification utilizes the general affinity matrix. Reactive Red 120-agarose and results in higher specific activity and yield of enzyme than previously reported. The stability of aerobically purified hydrogenase to oxygen is substantially greater than that reported for anaerobically isolated enzyme. Reduction of the aerobically purified enzyme in the presence of oxygen, however, results in the rapid loss of activity. R. japonicum cells accumulate nickel during heterotrophic growth and as non-growing cells. The hydrogenase constitutive mutant SR470 accumulates substantially greater amounts of nickel under both conditions. Kinetic studies indicate that the nickel uptake system in the hydrogenase constitutive mutant SR470 is upregulated relative to SRwt cells. The uptake system is specific for nickel, although a 10-fold excess (relative to nickel) of copper or zinc inhibits nickel uptake. The nickel uptake system appears to require energy. Under nickel-free conditions hydrogenase protein is not synthesized as determined by cross-reactivity with antibodies directed against hydrogenase, indicating that nickel regulates the formation of the enzyme as well as being a constituent of the active protein.
Radiological characterization of spent control rod assemblies
Lepel, E.A.; Robertson, D.E.; Thomas, C.W.; Pratt, S.L.; Haggard, D.L.
This document represents the final report of an ongoing study to provide radiological characterizations, classifications, and assessments in support of the decommissioning of nuclear power stations. This report describes the results of non-destructive and laboratory radionuclide measurements, as well as waste classification assessments, of BWR and PWR spent control rod assemblies. The radionuclide inventories of these spent control rods were determined by three separate methodologies, including (1) direct assay techniques, (2) calculational techniques, and (3) by sampling and laboratory radiochemical analyses. For the BWR control rod blade (CRB) and PWR burnable poison rod assembly (BPRA), {sup 60}Co and {sup 63}Ni, present in the stainless steel cladding, were the most abundant neutron activation products. The most abundant radionuclide in the PWR rod cluster control assembly (RCCA) was {sup 108m}Ag (130 yr halflife) produced in the Ag-In-Cd alloy used as the neutron poison. This radionuclide will be the dominant contributor to the gamma dose rate for many hundreds of years. The results of the direct assay methods agree very well ({+-}10%) with the sampling/radiochemical measurements. The results of the calculational methods agreed fairly well with the empirical measurements for the BPRA, but often varied by a factor of 5 to 10 for the CRB and the RCCA assemblies. If concentration averaging and encapsulation, as allowed by 10CFR61.55, is performed, then each of the entire control assemblies would be classified as Class C low-level radioactive waste.
Dissolution behavior of Caldag lateritic nickel ore subjected to a sequential organic acid leaching method
NASA Astrophysics Data System (ADS)
Kursunoglu, Sait; Kaya, Muammer
The dissolution behavior of Caldag lateritic nickel ore subjected to a sequential organic acid leaching method was investigated. The effects of the type of organic acid, acid concentration, leaching time, and leaching temperature on the lateritic nickel ore were examined. Organic acids were used individually prior to sequential leaching. Citric acid was more effective than the other two acids for the selective leaching of nickel and cobalt. An increase in the citric acid concentration negligibly affected the dissolution of the metals, whereas temperature exhibited a strong beneficial effect. Oxalic acid was determined to be the most appropriate organic acid for the second leaching step. After 8 h (4 h + 4 h) of leaching with organic acids (0.5 M citric + 0.5 M oxalic) in sequence at 90°C, 89.63% Ni, 82.89% Co, and 69.63% Fe were leached from the lateritic nickel ore. A sequential citric + oxalic acid leaching method could represent a viable alternative for the dissolution of metals from lateritic nickel ore.
Cosmogenic effects on Cu isotopes in IVB iron meteorites
NASA Astrophysics Data System (ADS)
Chen, Heng; Moynier, Frédéric; Humayun, Munir; Bishop, M. Cole; Williams, Jeffrey T.
We measured Cu isotope compositions of 12 out of the 14 known IVB iron meteorites. Our results show that IVB iron meteorites display a very large range of δ65Cu values (-5.84‰ < δ65Cu < -0.24‰; defined as per mil deviation of the 65Cu/63Cu ratio from the NIST-976 standard). These Cu isotopic data display clear correlations with W, Pt, and Os isotope ratios, which are very sensitive to secondary neutron capture due to galactic cosmic ray (GCR) irradiation. This demonstrates that δ65Cu in IVB irons is majorly modified by neutron capture by the reaction 62Ni(n,γ)63Ni followed by beta decay to 63Cu. Using correlations with Pt and Os neutron dosimeters, we calculated a pre-exposure δ65Cu of -0.3 ± 0.8‰ (95% conf.) of IVB irons that agrees well with the Cu isotopic compositions of other iron meteorite groups and falls within the range of chondrites. This shows that the volatile depletion of the IVB parent body is not due to evaporation that should have enriched IVB irons in the heavy Cu isotopes.
Method for determination of organohalogen pesticide residues in vegetable oil refinery by-products.
Young, S; Clower, M; Roach, J A
A method using gel permeation and Florisil column chromatographic cleanup techniques is described for determination of residues of nonpolar organohalogen pesticides and pesticide alteration products in vegetable oils and their refinery by-products. Supplemental Florisil separation and alkali cleanup techniques are used to facilitate determinations. Residues are determined with a 63Ni electron capture gas chromatographic detection system used in conjunction with 3 different gas chromatographic columns. Residue identities are confirmed by gas chromatography-mass spectrometry. Recoveries of 7 organohalogen pesticides, ranging from 90 to 103%, were determined by the supplemental Florisil separation technique to augment previously reported recovery data determined for initial GPC and Florisil cleanup steps. Soybean, peanut, and cottonseed deodorizer distillates and crude and refined oil, as well as additional refinery by-products, were analyzed. Nine to 13 organohalogen residues ranging from 0.5 to 6.3 ppm were determined in the 2 soybean deodorizer distillate samples used to develop and test the method. Identities of residues present at greater than or equal to 0.3 ppm were confirmed by gas chromatography-mass spectrometry. An intralaboratory trial of the method provided additional recovery and residue determination data as follows: Recoveries ranging from 102 to 116% were obtained for 4 pesticides added to peanut oil deodorizer distillate. Residues determined in 1 soybean deodorizer distillate sample supported previously obtained data for this sample. PMID:6698936
Ion mobility spectrometry of hydrazine, monomethylhydrazine, and ammonia in air with 5-nonanone reagent gas
NASA Technical Reports Server (NTRS)
Eiceman, G. A.; Salazar, M. R.; Rodriguez, M. R.; Limero, T. F.; Beck, S. W.; Cross, J. H.; Young, R.; James, J. T.
Hydrazine (HZ) and monomethylhydrazine (MMH) in air were monitored continuously using a hand-held ion mobility spectrometer equipped with membrane inlet, 63Ni ion source, acetone reagent gas, and ambient temperature drift tube. Response characteristics included detection limit, 6 ppb; linear range, 10-600 ppb; saturated response, >2 ppm; and stable response after 15-30 min. Ammonia interfered in hydrazines detection through a product ion with the same drift time as that for MMH and HZ. Acetone reagent gas was replaced with 5-nonanone to alter drift times of product ions and separate ammonia from MMH and HZ. Patterns in mobility spectra, ion identifications from mass spectra, and fragmentation cross-sections from collisional-induced dissociations suggest that drift times are governed by ion-cluster equilibria in the drift region of the mobility spectrometer. Practical aspects including calibration, stability, and reproducibility are reported from the use of a hand-held mobility spectrometer on the space shuttle Atlantis during mission STS-37.
Combined extraction-cleanup column chromatographic procedure for determination of dicofol in avian eggs
Krynitsky, A.J.; Stafford, C.J.; Wiemeyer, Stanley N.
Dicofol in avian eggs was completely oxidized to dichlorobenzophenone (DCBP) when a hexane Soxhlet extraction procedure was used. This degradation did not occur with other avian tissues (muscle and liver). For this reason, a combined extraction-cleanup column chromatographic procedure, without added heat, was developed for the determination of dicofol in avian eggs. Homogenized subsamples of eggs were mixed with sodium sulfate, and the mixture was added as the top layer on a column prepacked with Florisil. The dicofol and other compounds of interest were then eluted with ethyl ether-hexane. The extracts, relatively free from lipids, were quantitated on a gas chromatograph equipped with a 63Ni electron-capture detector and a methyl silicone capillary column. Recoveries from chicken eggs, fortified with dicofol and other DDT-related compounds, averaged 96%. Analysis of eggs of eastern screech-owls, fed a meat diet containing 10 ppm technical Kelthane, showed that both dicofol and DCBP were present. Results were confirmed by gas chromatography/mass spectrometry. This method is rapid and reliable, involves a minimum of sample handling, and is well suited for high volume determination of dicofol in eggs and other avian tissues.
Preliminary survey of separations technology applicable to the pretreatment of Hanford tank waste (1992--1993)
Lawrence, W.E.; Kurath, D.E.
The US Department of Energy has established the Tank Waste Remediation System (TWRS) to manage and dispose of radioactive wastes stored at the Hanford Site. Within this program are evaluations of pretreatment system alternatives through literature reviews. The information in this report was collected as part of this project at Pacific Northwest Laboratory. A preliminary survey of literature on separations recently entered into the Hanford electronic databases (1992--1993) that have the potential for pretreatment of Hanford tank waste was conducted. Separation processes that can assist in the removal of actinides (uranium, plutonium, americium), lanthanides, barium, {sup 137}Cs, {sup 90}Sr,{sup 129 }I, {sup 63}Ni, and {sup 99}Tc were evaluated. Separation processes of interest were identified through literature searches, journal reviews, and participation in separation technology conferences. This report contains brief descriptions of the potential separation processes, the extent and/or selectivity of the separation, the experimental conditions, and observations. Information was collected on both national and international separation studies to provide a global perspective on recent research efforts.
Advanced Sensor Technologies for Next-Generation Vehicles
Sheen, S H; Chien, H T; Gopalsami, N; Jendrzejczyk, A; Raptis, A C
This report summarizes the development of automobile emissions sensors at Argonne National Laboratory. Three types of sensor technologies, i.e., ultrasound, microwave, and ion-mobility spectrometry (IMS), were evaluated for engine-out emissions monitoring. Two acoustic sensor technologies, i.e., surface acoustic wave and flexural plate wave, were evaluated for detection of hydrocarbons. The microwave technique involves a cavity design and measures the shifts in resonance frequency that are a result of the presence of trace organic compounds. The IMS technique was chosen for further development into a practical emissions sensor. An IMS sensor with a radioactive {sup 63}Ni ion source was initially developed and applied to measurement of hydrocarbons and NO{sub x} emissions. For practical applications, corona and spark discharge ion sources were later developed and applied to NO{sub x} emission measurement. The concentrations of NO{sub 2} in dry nitrogen and in a typical exhaust gas mixture are presented. The sensor response to moisture was evaluated, and a cooling method to control the moisture content in the gas stream was examined. Results show that the moisture effect can be reduced by using a thermoelectric cold plate. The design and performance of a laboratory prototype sensor are described.
Differences in genotoxic activity of alpha-Ni3S2 on human lymphocytes from nickel-hypersensitized and nickel-unsensitized donors.
Arrouijal, F Z; Marzin, D; Hildebrand, H F; Pestel, J; Haguenoer, J M
The genotoxic activity of alpha-Ni3S2 was assessed on human lymphocytes from nickel-hypersensitized (SSL) and nickel-unsensitized (USL) subjects. Three genotoxicity tests were performed: the sister chromatid exchange (SCE) test, the metaphase analysis test and the micronucleus test. (i) The SCE test (3-100 micrograms/ml) showed a weak but statistically significant increase in the number of SCE in both lymphocyte types with respect to controls, USL presenting a slightly higher SCE incidence but only at one concentration. (ii) The metaphase analysis test demonstrated a high dose-dependent clastogenic activity of alpha-Ni3S2 in both lymphocyte types. The frequency of chromosomal anomalies was significantly higher in USL than in SSL for all concentrations applied. (iii) The micronucleus test confirmed the dose-dependent clastogenic activity of alpha-Ni3S2 and the differences already observed between USL and SSL, i.e. the number of cells with micronuclei was statistically higher in USL. Finally, the incorporation study with alpha-63Ni3S2 showed a higher uptake of its solubilized fraction by USL. This allows an explanation of the different genotoxic action of nickel on the two cell types. In this study we demonstrated that hypersensitivity has an influence on the incorporation of alpha-Ni3S2 and subsequently on the different induction of chromosomal aberrations in human lymphocytes. PMID:1602972
Induced Radioactivity and Waste Classification of Reactor Zone Components of the Chernobyl Nuclear Power Plant Unit 1 After Final Shutdown
Bylkin, Boris K.; Davydova, Galina B.; Zverkov, Yuri A.; Krayushkin, Alexander V.; Neretin, Yuri A.; Nosovsky, Anatoly V.; Seyda, Valery A.; Short, Steven M.
The dismantlement of the reactor core materials and surrounding structural components is a major technical concern for those planning closure and decontamination and decommissioning of the Chernobyl Nuclear Power Plant (NPP). Specific issues include when and how dismantlement should be accomplished and what the radwaste classification of the dismantled system would be at the time it is disassembled. Whereas radiation levels and residual radiological characteristics of the majority of the plant systems are directly measured using standard radiation survey and radiochemical analysis techniques, actual measurements of reactor zone materials are not practical due to high radiation levels and inaccessibility. For these reasons, neutron transport analysis was used to estimate induced radioactivity and radiation levels in the Chernobyl NPP Unit 1 reactor core materials and structures.Analysis results suggest that the optimum period of safe storage is 90 to 100 yr for the Unit 1 reactor. For all of the reactor components except the fuel channel pipes (or pressure tubes), this will provide sufficient decay time to allow unlimited worker access during dismantlement, minimize the need for expensive remote dismantlement, and allow for the dismantled reactor components to be classified as low- or medium-level radioactive waste. The fuel channel pipes will remain classified as high-activity waste requiring remote dismantlement for hundreds of years due to the high concentration of induced {sup 63}Ni in the Zircaloy pipes.
[Gas chromatographic method for the analysis of polychlorinated biphenyls in pine needles].
Zhu, X; Zhang, X; Yao, J; Liu, Z; Lu, P
Polychlorinated biphenyls (PCBs) are a class of 209 chemical compounds, in which 1-10 chlorine atoms are attached to a biphenyl molecule. PCBs are members of halogenated aromatic group of environmental pollutants that have been identified worldwide in diverse environmental matrices. PCBs in air, soils, sediment, water, transformer oils and other environmental matrices have been determined in the past years. In this work a method for routine analysis of PCBs in pine needles has been developed. First, extractions were carried out in Soxhlet apparatus with n-hexane as solvent. Then, a silica gel chromatographic column was applied to pretreat the pine needle samples. The reference standard used was clophen 50. The recovery was about 90%, so the feasibility and reliability were assured. After the analysis of PCBs in pine needle samples from four different regions, the distribution of PCBs in environment can be discussed and monitored. In this method, a Shimadzu GC-7A gas chromatograph equipped with a 63Ni electron capture detector was used for the analysis of PCBs. From the results, we can see the PCB pollution in different regions. So evaluation of air pollution level through foliage data is feasible. The sample preparation and analytical method mentioned in this paper is reliable and simple. PMID:12552848
Development of scaling factors for the activated concrete of the KRR-2.
Hong, Sang-Bum; Kang, Mun-Ja; Lee, Ki-Won; Chung, Un-Soo
The biological shielding concrete of KRR-2 was activated by a thermal neutron reaction during the operation of the reactor, thus a variety of radionuclides were generated in the concrete. In order to verify the radioactivity for the final disposal of waste and to achieve a more efficient cutting of the concrete, the radioactivity inventories and distributions of the activated concrete were evaluated. The activity of gamma-emitting radionuclides was measured by using an HPGe detector. The beta-emitting radionuclides were measured by an oxidation/combustion method for (3)H and (14)C and a combined method of an extraction chromatography and a liquid scintillation for (55)Fe and (63)Ni. The dominant radioactive nuclides in the activated concrete were (3)H, (14)C, (55)Fe and (60)Co, and the maximum gamma activity was 105Bq/g at the surface around the thermal column. The specific activities of all the nuclides were found to decrease almost linearly on a logarithmic scale along the depth from the inner surface of the concrete. Equations for scaling factors were obtained by a linear regression of logarithms from the radioactivity data of (3)H/(60)Co, (14)C/(60)Co and (55)Fe/(60)Co nuclide pairs of the activated concrete. The scaling factors can be utilized for the estimation of beta radioactivity without the time consuming separation processes of the nuclides. PMID:19303787
Optimization of the electrochemical performance of a Ni/Ce0.9Gd0.1O2-δ-impregnated La0.57Sr0.15TiO3 anode in hydrogen
NASA Astrophysics Data System (ADS)
Xia, Tian; Brüll, Annelise; Grimaud, Alexis; Fourcade, Sébastien; Mauvy, Fabrice; Zhao, Hui; Grenier, Jean-Claude; Bassat, Jean-Marc
A-site deficient perovskite La0.57Sr0.15TiO3 (LSTO) materials are synthesized by a modified polyacrylamide gel route. X-ray diffraction pattern of LSTO indicates an orthorhombic structure. The thermal expansion coefficient of LSTO is 10.0 × 10-6 K-1 at 600 °C in 5%H2/Ar. LSTO shows an electrical conductivity of 2 S cm-1 at 600 °C in 3%H2O/H2. A new composite material, containing the porous LSTO backbone impregnated with small amounts of Ce0.9Gd0.1O2-δ (CGO) (3.4-8.3 wt.%) and Ni/Cu (2.0-6.3 wt.%), is investigated as an alternative anode for solid oxide fuel cells (SOFCs). Because of the substantial electro-catalytic activity of the fine and well-dispersed Ni particles on the surface of the ceramic framework, the polarization resistance of 6.3%Ni-8.3%CGO-LSTO anode reaches 0.73 Ω cm2 at 800 °C in 3%H2O/H2. In order to further improve the anodic performance, corn starch and carbon black are used as pore-formers to optimize the microstructure of anodes.
Characterization and purification of carbon monoxide dehydrogenase from Methanosarcina barkeri.
Krzycki, J A; Zeikus, J G
Carbon monoxide-dependent production of H2, CO2, and CH4 was detected in crude cell extracts of acetate-grown Methanosarcina barkeri. This metabolic transformation was associated with an active methyl viologen-linked CO dehydrogenase activity (5 to 10 U/mg of protein). Carbon monoxide dehydrogenase activity was inhibited 85% by 10 microM KCN and was rapidly inactivated by O2. The enzyme was nearly homogeneous after 20-fold purification, indicating that a significant proportion of soluble cell protein was CO dehydrogenase (ca. 5%). The native purified enzyme displayed a molecular weight of 232,000 and a two-subunit composition of 92,000 and 18,000 daltons. The enzyme was shown to contain nickel by isolation of radioactive CO dehydrogenase from cells grown in 63Ni. Analysis of enzyme kinetic properties revealed an apparent Km of 5 mM for CO and a Vmax of 1,300 U/mg of protein. The spectral properties of the enzyme were similar to those published for CO dehydrogenase from acetogenic anaerobes. The physiological functions of the enzyme are discussed. Images PMID:6425262
[Development of a chemical ionization time-of-flight mass spectrometer for continuous measurements of atmospheric hydroxyl radical].
Dou, Jian; Hua, Lei; Hou, Ke-Yong; Jiang, Lei; Xie, Yuan-Yuan; Zhao, Wu-Duo; Chen, Ping; Wang, Wei-Guo; Di, Tian; Li, Hai-Yang
A home-made chemical ionization time-of-flight mass spectrometer (TOFMS) has been developed for continuous measurements of atmospheric hydroxyl radical. Based on the atmospheric pressure chemical ionization technique, an ionization source with orthogonal dual tube structure was adopted in the instrument, which minimized the interference between the reagent gas ionization and the titration reaction. A 63Ni radioactive source was fixed inside one of the orthogonal tubes to generate reactant ion of NO(-)(3) from HNO3 vapor. Hydroxyl radical was first titrated by excess SO2 to form equivalent concentrations of H2SO4 in the other orthogonal tube, and then reacted with NO(-)(3) ions in the chemical ionization chamber, leading to HSO(-)(4) formation. The concentration of atmospheric hydroxyl radical can be directly calculated by measuring the intensities of the HSOj product ions and the NO(-)(3) reactant ions. The analytical capability of the instrument was demonstrated by measuring hydroxyl radical in laboratory air, and the concentration of the hydroxyl radical in the investigated air was calculated to be 1.6 x 106 molecules*cm ', based on 5 seconds integration. The results have shown that the instrument is competent for in situ continuous measurements of atmospheric trace radical. PMID:25055654
Assessment of river Po sediment quality by micropollutant analysis.
Camusso, Marina; Galassi, Silvana; Vignati, Davide
Trace metals, PCB congeners and DDT homologues were determined in composite sediment samples collected from 10 representative sites along the river Po in two separate seasons. The aim was to identify the most anthropogenically impacted areas for future monitoring programmes and to aid development of Italian sediment quality criteria. The surface samples were collected during low flow conditions. Trace metal concentrations were assayed by electrothermal (Cd, Co, Cr, Cu, Ni, Pb), flame (Fe, Mn, Zn) or hydride generation (As) atomic absorption spectrometry after microwave assisted acid digestion. Hg was determined on solid samples by automated analyser. Organic microcontaminants were determined by gas-chromatography with 63Ni electron capture detector after Soxhlet extraction. Concentrations of trace metals, total PCB and DDT homologues showed two distinct peaks at the sites immediately downstream of Turin and Milan, respectively, and in each case decreased progressively further downstream. Principal component analysis identified three major factors (from a multi-dimensional space of 35 variables) which explained 85-90% of the total observed variance. The first and second factors corresponded to anthropogenic inputs and geological factors on sediment quality; the third included seasonal processes of minor importance. Sediment quality assessment identified Cd, Cu, Hg, Pb, Zn and organic microcontaminants as posing the most serious threats to river sediment quality. A reference site within the Po basin provided useful background values. Moderate pollution by organochlorine compounds was ascribed both to local sources and to atmospheric deposition. PMID:12153015
The IFIN-HH triple coincidence liquid scintillation counter.
Razdolescu, A C; Broda, R; Cassette, P; Simpson, B R S; Van Wyngaardt, W M
The paper summarizes the IFIN-HH triple coincidence liquid scintillation counter used for the implementation of the TDCR method. The electronic unit was recently extended to record the three individual double coincidence ratios to take into account the differences in the quantum efficiencies of the three-photomultiplier tubes. Some details of the electronic system and the data processing are given. The critical point of a TDCR counter is to adjust correctly the discriminator levels on the three channels under the single electron peak. The paper describes the method of adjustment based on the evolution of the dark counting rate versus the discriminator level. Also indicated is the influence of the discrimination level on the activity results as measured at IFIN-HH using a 3H standard. The performances of the IFIN-HH TDCR counter was checked against the measurement results of the TDCR counters of CSIR NML (South Africa), RC (Poland) and LNHB (France). A set of ready-to-measure 63Ni sources in liquid scintillator, in sealed counting vials, was prepared and dispatched for measurement to all these laboratories. The paper describes designs of the TDCR counters used. An analysis and discussion of the measurement results is given. PMID:16563781
Studies on important radionuclides for the safety of a radioactive waste disposal site: Correlation between easily measurable gamma emitters and long-lived radionuclides
Raymond, A.; Lagarde, B.; Pitiot, A.
To comply with the regulations laid down by the French safety authorities for a national surface disposal site, one must obtain a good evaluation of the activity of the long-lived nuclides in each individual package. Because this cannot be done on a routine basis by direct nondestructive measurements, experiments are being conducted in France to calculate the activity of long-lived nuclides from the measured activity of key nuclides ({sup 60}Co and {sup 137}Cs). This is achieved through the use of scaling factors and correlation functions that are calculated from the analysis of a limited number of representative waste samples. The first results obtained for some typical French pressurized water reactor radioactive wastes, including ion-exchange resins, evaporator concentrates, and filter cartridges, are presented. Significant correlations are observed for the {sup 63}Ni/{sup 60}Co and {sup 94}Nb/{sup 60}Co nuclide pairs, while {sup 14}C does not seem to correlate with {sup 60}Co. A good correlation between {sup 137}Cs and {sup 90}Sr is established for resins, while in the case of filters, only a tendency to correlation appears. This evaluation work is only at a preliminary stage, and much improvement of the results presented here is expected from research programs being carried out in this field by Electricite de France, commissariat a l`Energie Atomique, and the French National Agency for Radioactive Waste Management in cooperation with the Commission of the European Communities.
Paracoccidioides spp. ferrous and ferric iron assimilation pathways
Bailão, Elisa Flávia L. C.; Lima, Patrícia de Sousa; Silva-Bailão, Mirelle G.; Bailão, Alexandre M.; Fernandes, Gabriel da Rocha; Kosman, Daniel J.; Soares, Célia Maria de Almeida
Iron is an essential micronutrient for almost all organisms, including fungi. Usually, fungi can uptake iron through receptor-mediated internalization of a siderophore or heme, and/or reductive iron assimilation (RIA). Traditionally, the RIA pathway consists of ferric reductases (Fres), ferroxidase (Fet3) and a high-affinity iron permease (Ftr1). Paracoccidioides spp. genomes do not present an Ftr1 homolog. However, this fungus expresses zinc regulated transporter homologs (Zrts), members of the ZIP family of membrane transporters that are able in some organisms to transport zinc and iron. A 2,3,5-triphenyltetrazolium chloride (TTC)-overlay assay indicates that both Pb01 and Pb18 express a ferric reductase activity; however, 59Fe uptake assays indicate that only in Pb18 is this activity coupled to a reductase-dependent iron uptake pathway. In addition, Zrts are up-regulated in iron deprivation, as indicated by RNAseq and qRT-PCR using Pb01 transcripts. RNAseq strategy also demonstrated that transcripts related to siderophore uptake and biosynthesis are up-regulated in iron-deprived condition. The data suggest that the fungus could use both a non-classical RIA, comprising ferric reductases and Fe/Zn permeases (Zrts), and siderophore uptake pathways under iron-limited conditions. The study of iron metabolism reveals novel surface molecules that could function as accessible targets for drugs to block iron uptake and, consequently, inhibit pathogen's proliferation. PMID:26441843
Fate of blood meal iron in mosquitos
Zhou, Guoli; Kohlhepp, Pete; Geiser, Dawn; Frasquillo, Maria del Carmen; Vazquez-Moreno, Luz; Winzerling, Joy J.
Iron is an essential element of living cells and organisms as a component of numerous metabolic pathways. Hemoglobin and ferric-transferrin in vertebrate host blood are the two major iron sources for female mosquitoes. We used inductively coupled plasma mass spectrometry (ICP-MS) and radioisotope-labeling to quantify the fate of iron supplied from hemoglobin or as transferrin in Aedes aegypti. At the end of the first gonotrophic cycloe, ~87% of the ingested total meal heme iron was excreted, while 7% was distributed into the eggs and 6% was stored in different tissues. In contrast, ~8% of the iron provided as transferrin was excreted and of that absorbed, 77% was allocated to the eggs and 15% distributed in the tissues. Further analyses indicate that of the iron supplied in a blood meal, ~7% appears in the eggs and of this iron 98% is from hemoglobin and 2% from ferric-transferrin. Whereas of iron from a blood meal retained in body of the female, ~97% is from heme and <1 % is from transferrin. Evaluation of iron-binding proteins in hemolymph and egg following intake of 59Fe-transferrin revealed that ferritin is iron loaded in these animals, and indicate that this protein plays a critical role in meal iron transport and iron storage in eggs in A. aegypti. PMID:17689557
Iron Absorption from Two Milk Formulas Fortified with Iron Sulfate Stabilized with Maltodextrin and Citric Acid
Pizarro, Fernando; Olivares, Manuel; Maciero, Eugenia; Krasnoff, Gustavo; Cócaro, Nicolas; Gaitan, Diego
Background: Fortification of milk formulas with iron is a strategy widely used, but the absorption of non-heme iron is low. The purpose of this study was to measure the bioavailability of two iron fortified milk formulas designed to cover toddlers' nutritional needs. These milks were fortified with iron sulfate stabilized with maltodextrin and citric acid. Methods: 15 women (33–47 years old) participated in study. They received on different days, after an overnight fast, 200 mL of Formula A; 200 mL of Formula B; 30 mL of a solution of iron and ascorbic acid as reference dose and 200 mL of full fat cow's milk fortified with iron as ferrous sulfate. Milk formulas and reference dose were labeled with radioisotopes 59Fe or 55Fe, and the absorption of iron measured by erythrocyte incorporation of radioactive Fe. Results: The geometric mean iron absorption corrected to 40% of the reference dose was 20.6% for Formula A and 20.7% for Formula B, versus 7.5% of iron fortified cow's milk (p < 0.001). The post hoc Sheffé indeed differences between the milk formulas and the cow's milk (p < 0.001). Conclusion: Formulas A and B contain highly bioavailable iron, which contributes to covering toddlers' requirements of this micronutrient. PMID:26529007
Split dose studies on the erythropoietic effects of cadmium
Hogan, G.R.; Razniak, S.L.
The processes of red blood cell production and release, i.e., erythropoiesis, are complex and involve a series of cell divisions and maturation phases during which hemoglobin is synthesized. The formation of hemoglobin is an integral process and functions as one of the factors that control the rate and extent of erythropoiesis. Therefore, exogenous and endogenous factors which affect the synthesis of hemoglobin would secondarily affect the rate and extent of the erythropoietic process. Incorporation of radioactively labeled iron ({sup 59}Fe) into the hemoglobin of erythrocyte precursor cells in the process of hemoglobin production, is a precise measurement of erythropoiesis. Another widely used indicator of the rate and extent of hemoglobin synthesis, and thus, erythropoiesis, is the activity level of the enzyme, delta-aminolevulinic acid dehydratase (ALAD). This enzyme plays a crucial role in hemoglobin formation by promoting the condensation of two moles of aminolevulinic acid to form one mole of porphobilinogen. The degree of ALAD activity and/or its availability to perform its coupling function would, of course, affect the synthesis of hemoglobin which in turn would influence the total erythropoietic progression. The purposes of the studies here were to compare the erythropoietic effects of a single dosage of cadmium to split dosages. 19 refs., 21 figs.
Mitochondrial iron accumulation exacerbates hepatic toxicity caused by hepatitis C virus core protein.
Sekine, Shuichi; Ito, Konomi; Watanabe, Haruna; Nakano, Takafumi; Moriya, Kyoji; Shintani, Yoshizumi; Fujie, Hajime; Tsutsumi, Takeya; Miyoshi, Hideyuki; Fujinaga, Hidetake; Shinzawa, Seiko; Koike, Kazuhiko; Horie, Toshiharu
Patients with long-lasting hepatitis C virus (HCV) infection are at major risk of hepatocellular carcinoma (HCC). Iron accumulation in the livers of these patients is thought to exacerbate conditions of oxidative stress. Transgenic mice that express the HCV core protein develop HCC after the steatosis stage and produce an excess of hepatic reactive oxygen species (ROS). The overproduction of ROS in the liver is the net result of HCV core protein-induced dysfunction of the mitochondrial respiratory chain. This study examined the impact of ferric nitrilacetic acid (Fe-NTA)-mediated iron overload on mitochondrial damage and ROS production in HCV core protein-expressing HepG2 (human HCC) cells (Hep39b cells). A decrease in mitochondrial membrane potential and ROS production were observed following Fe-NTA treatment. After continuous exposure to Fe-NTA for six days, cell toxicity was observed in Hep39b cells, but not in mock (vector-transfected) HepG2 cells. Moreover, mitochondrial iron ((59)Fe) uptake was increased in the livers of HCV core protein-expressing transgenic mice. This increase in mitochondrial iron uptake was inhibited by Ru360, a mitochondrial Ca(2+) uniporter inhibitor. Furthermore, the Fe-NTA-induced augmentation of mitochondrial dysfunction, ROS production, and cell toxicity were also inhibited by Ru360 in Hep39b cells. Taken together, these results indicate that Ca(2+) uniporter-mediated mitochondrial accumulation of iron exacerbates hepatocyte toxicity caused by the HCV core protein. PMID:25545986
The iron-binding properties of hen ovotransferrin.
Williams, J; Evans, R W; Moreton, K
1. The distribution of iron between the two iron-binding sites in partially saturated ovotransferrin was studied by labelling with 55Fe and 59Fe and by gel electrophoresis in a urea-containing buffer. 2. When iron is added in the form of chelate complexes at alkaline pH, binding occurs preferentially at the N-terminal binding site. In acid, binding occurs preferentially at the C-terminal site. 3. When simple iron donors (ferric and ferrous salts) are used the metal is distributed at random between the binding sites, as judged by the gel-electrophoresis method. The double-isotope method shows a preference of ferrous salts for the N-terminal site. 4. Quantitative treatment of the results of double-isotope labelling suggests that in the binding of iron to ovotransferrin at alkaline pH co-operative interactions between the sites occur. These interactions are apparently absent in the displacement of copper and in the binding of iron at acid pH. Images Fig. 1. PMID:697734
Absorption of zinc and iron by rats fed meals containing sorghum food products
Stuart, S.M.A.; Johnson, P.E.; Hamaker, B.; Kirleis, A.
Zinc and iron absorption from freeze-dried traditionally-prepared sorghum food products was studied in rats. After a period of marginal zinc or iron depletion, rats were fed test meals containing 1 of 4 sorghum foods cooked maize gruel or an inorganic mineral each of which was extrinsically labeled with either /sup 65/Zn or /sup 59/Fe before being added to the diets. Absorption was determined by whole body percent retention of the initial radioisotope dose over a period of 19 days. Iron was highly available from all products tested (75-83%) with no significant differences in absorption among groups (p>0.05). Zinc from fermented Aceta (97%) was more available than that from the other sorghum products (69-78%) or maize gruel (76%). Zinc from acid To (78%) and Aceta (97%) was as available as that from zinc oxide in the control diet (93%) (p>0.05). There were no significant differences in zinc absorption among groups fed Acid To (78%), neutral To (76), alkali To (69%) or maize gruel (76%) (p<0.05). Phytate in the fermented Aceta was 33% lower than in the other sorghum foods. Iron and zinc were highly available from all sorghum foods. Reduction phytate by fermentation increased Zn availability.
Physiological Characteristics of Fe Accumulation in the `Bronze' Mutant of Pisum sativum L., cv `Sparkle' E107 (brz brz) 1
Welch, Ross M.; LaRue, Thomas A.
The pea (Pisum sativum L.) mutant, E107 (brz, brz) accumulated extremely high concentrations of Fe in its older leaves when grown in light rooms in either defined nutrient media or potting mix, or outdoors in soil. Leaf symptoms (bronze color and necrosis) were correlated with very high Fe concentrations. When E107 plants were grown in nutrient solutions supplied 10 μm Fe, as the Fe(III)-N,N′-ethylenebis[2-(2-hydroxyphenyl)glycine] chelate, their roots released higher concentrations of Fe(III) reducing substances to the nutrient media than did roots of the normal parent cv, `Sparkle.' Reciprocal grafting experiments demonstrated that the high concentrations of Fe in the shoot was controlled by the genotype of the root. In short-term 59Fe uptake studies, 15-day-old E107 seedlings exhibited higher rates of Fe absorption than did `Sparkle' seedlings under Fe-adequate growth conditions. Iron deficiency induced accelerated short-term Fe absorption rates in both mutant and normal genotypes. Iron-treated E107 roots also released larger amounts of both protons and Fe(III) reductants into their nutrient media than did iron-treated `Sparkle' roots. Furthermore, the mutant translocated proportionately more Fe to its shoot than did the parent regardless of Fe status. PMID:16667529
The cell-free synthesis of cytochrome c by a microsomal fraction from rat liver
González-Cadavid, Néstor F.; Ortega, Juan P.; González, Magally
Conditions were investigated for demonstrating the synthesis in vitro of the complete molecule of cytochrome c by isolated liver microsomal systems from partially hepatectomized rats. It was first found that in vivo the early labelled cytochrome c associated with the microsomal fraction required, by comparison with the mitochondrial pool, more drastic conditions of extraction and its binding was less affected by freezing and thawing of the subcellular particles. The procedure of extraction and purification of cytochrome c had to be modified accordingly, to assure the recovery of the recently synthesized molecule. Several subcellular fractions were isolated from regenerating liver with a homogenization medium containing either 5 or 10mm-Mg2+ and most of them were active in the synthesis of the cytochrome c apoprotein. The microsomal fraction, in the presence of either cell sap or pH5.0 fraction, was also able to incorporate [59Fe]haemin, δ-amino[3H]laevulic acid and 55Fe into the prosthetic group of cytochrome c. These experiments confirm firmly the conclusions of our previous results obtained in vivo showing that both the apoprotein and the haem moieties are made and linked together on cytoplasmic ribosomes and only then is the complete molecule transferred to the mitochondria. PMID:5131727
Ferristatin II Promotes Degradation of Transferrin Receptor-1 In Vitro and In Vivo
Kim, Jonghan; Luo, Flora; Sanford, Jack; Chen, Juxing; Enns, Caroline; Wessling-Resnick, Marianne
Previous studies have shown that the small molecule iron transport inhibitor ferristatin (NSC30611) acts by down-regulating transferrin receptor-1 (TfR1) via receptor degradation. In this investigation, we show that another small molecule, ferristatin II (NSC8679), acts in a similar manner to degrade the receptor through a nystatin-sensitive lipid raft pathway. Structural domains of the receptor necessary for interactions with the clathrin pathway do not appear to be necessary for ferristatin II induced degradation of TfR1. While TfR1 constitutively traffics through clathrin-mediated endocytosis, with or without ligand, the presence of Tf blocked ferristatin II induced degradation of TfR1. This effect of Tf was lost in a ligand binding receptor mutant G647A TfR1, suggesting that Tf binding to its receptor interferes with the drug's activity. Rats treated with ferristatin II have lower TfR1 in liver. These effects are associated with reduced intestinal 59Fe uptake, lower serum iron and transferrin saturation, but no change in liver non-heme iron stores. The observed hypoferremia promoted by degradation of TfR1 by ferristatin II appears to be due to induced hepcidin gene expression. PMID:23894616
Apotransferrin has a second mechanism for anticandidal activity through binding of Candida albicans.
Han, Yongmoon
It has been reported that transferrin has antibacterial and antifungal activities via iron chelation in the environment surrounding the microbes. In the present study, we investigated whether the binding of transferrin to Candida albicans mediates growth inhibition. By using cultures that contained iron-free (apo)transferrin glycoprotein either in contact with candidal cells or separated from candidal cells by a dialysis membrane, we distinguished the growth inhibition by transferrin-cell interaction from that of simple iron chelation. Maximal growth inhibition always occurred when the apotransferrin interacted directly with the cells. Additionally, there was partial inhibition even when candidal cells were in contact with iron-saturated transferrin. Binding studies with (59)Fe(3+) radiolabeled-transferrin indicated that the apo-protein can bind to the candidal cell surface. The binding sites were saturable and it was dose dependent. Chemicals (hydrogen peroxide, dithiothreitol, sodium dodecyl sulfate) blocked transferrin binding to C. albicans, and among the three, hydrogen peroxide (HP) was the most effective for the blocking. When HP-treated yeast cells were added to the culture that was pretreated with apotransferrin, candidal cell growth increased by 5-fold as compared to the growth of HP-untreated candidal cells under apotransferrin-regulation (P < 0.05). Combined all data together, it was concluded that transferrin has a second mechanism of anticandidal activity that is mediated by binding to the surface of C. albicans yeast cells. PMID:24155020
Benzene toxicity: emphasis on cytosolic dihydrodiol dehydrogenases
Bolcsak, L.E.
Blood dyscrasias such as leukopenia and anemia have been clearly identified as consequences of chronic benzene exposure. The metabolites, phenol, catechol, and hydroquinone produced inhibition of /sup 59/Fe uptake in mice which followed the same time course as that produced by benzene. The inhibitor of benzene oxidation, 3-amino-1,2,4-triazole, mitigated the inhibitory effects of benzene and phenol only. These data support the contention that benzene toxicity is mediated by a metabolite and suggest that the toxicity of phenol is a consequence of its metabolism to hydroquinone and that the route of metabolism to catechol may also contribute to the production of toxic metabolite(s). The properties of mouse liver cytosolic dihydrodiol dehydrogenases were examined. These enzymes catalyze the NADP/sup +/-dependent oxidation of trans-1,2-dihydro-1,2-dihydroxybenzene (BDD) to catechol, a possible toxic metabolite of benzene produced via this metabolic route. Four distinct dihydrodiol dehydrogenases (DD1, DD2, DD3, and DD4) were purified to apparent homogeneity as judged by SDS polyacrylamide gel electrophoresis and isoelectric focusing. DD1 appeared to be identical to the major ketone reductase and 17..beta..-hydroxysteroid dehydrogenase activity in the liver. DD2 exhibited aldehyde reductase activity. DD3 and DD4 oxidized 17..beta..-hydroxysteroids, but no carbonyl reductase activity was detected. These relationships between BDD dehydrogenases and carbonyl reductase and/or 17..beta..-hydroxysteroid dehydrogenase activities were supported by several lines of evidence.
Specific binding of lactoferrin to brush-border membrane: Ontogeny and effect of glycan chain
Davidson, L.A.; Loennerdal, B. )
Bioavailability of iron from human milk is exceptionally high. It has been suggested that lactoferrin, the major iron-binding protein in human milk, may participate in this high iron bioavailability from milk. The authors examined the interaction of lactoferrin with the intestinal brush-border membrane using the rhesus monkeys as a model. Brush-border membrane vesicles were prepared from monkeys of various ages. Binding studies with {sup 59}Fe-labeled human and monkey lactoferrin were performed to examine interaction of lactoferrin with the brush-border membrane. Specific saturable binding of lactoferrin was found at all ages studied. The dissociation constant for lactoferrin-receptor binding was 9 {times} 10{sup {minus}6} M. In contrast, no binding of serum transferrin or bovine lactoferrin occurred. Removal of fucose from the lactoferrin glycans resulted in a significant decrease in binding. It was concluded that lactoferrin in milk may function in the process of iron absorption through interaction with a small intestinal receptor and that fucosylated glycans on the carbohydrate chain of lactoferrin are necessary for receptor recognition.
Giant magneto-impedance and stress-impedance effects of microwire composites for sensing applications
NASA Astrophysics Data System (ADS)
Qin, F. X.; Peng, H. X.; Popov, V. V.; Phan, M. H.
Composites consisting of glass-coated amorphous microwire Co 68.59Fe 4.84Si 12.41B 14.16 and 913 E-glass prepregs were designed and fabricated. The influences of tensile stress, annealing and number of composite layers on the giant magneto-impedance (GMI) and giant stress-impedance (GSI) effects in these composites were investigated systematically. It was found that the application of tensile stress along the microwire axis or an increase in the number of composite layers reduced the GMI effect and increased the circular anisotropy field, while the annealing treatment had a reverse effect. The value of matrix-wire interfacial stress calculated via the GMI profiles coincided with the value of the applied effective tensile stress to yield similar GMI profiles. Enhancement of the GSI effect was achieved in the composites relative to their single microwire inclusion. These findings are important for the development of functional microwire-based composites for magnetic- and stress-sensing applications. They also open up a new route for probing the interfacial stress in fibre-reinforced polymer (FRP) composites.
Effect of fulvic acids on the electrolytes physiology in vertebrates
NASA Astrophysics Data System (ADS)
Morales, O. Y.; Navarrete, J. M.; Gracia, I.; Macias, L.; Rivera, M.; Sanchez, F.
Fulvic acids are the active principle in humus fertilizers which are the cause of better absorption of mineral ions from soil to plant tissues. Tested in mice by making use of radioactive labeled ions, they showed their action of enhancing by a factor greater than two the filtration through liver of PO 43- and Ca 2+ from digestive tract to blood serum as well as through kidney from blood serum to urine. Following this research, Fe 3+ and I 1- ions labeled with 59Fe and 131I have been tested and reported in the present paper. Results showed that iron ions are completely fixed in red cells, with no residue eliminated by urine, while iodine ions are fixed in thyroid gland, with some residue eliminated by urine. Both ions were fixed in said tissues by factors larger than two when they are escorted by fulvic acids. A general distribution of these ions in blood, urine, feces, liver, kidney and thyroid gland has been surveyed, trying to find the earliest effect of fulvic acids in the physiology of vertebrates.
Uptake of trace metals by the clam Macoma inquinata from clean and oil-contaminated detritus
Crecelius, E.A.; Augenfeld, J.M.; Woodruff, D.L.; Anderson, J.W.
In recent years there has been increasing concern about the entry of petroleum hydrocarbon (PHC) into the marine environment and the effects of such entry on the composition and functioning of the marine ecosystem. Few reports have been published on the possible effect of oil on the uptake of metals from water or sediments by animals. The possibility of such effects is indicated by the work of Fletcher et al. (1979), who showed that crude oil causes a reduction in blood plasma copper concentrations in fish, and Payne et al. (1978) who reported that petroleum affected chloride regulation in fish. Luoma and Jenne (1977) have shown that the availability of sediment-bound metals to a deposit-feeding clam depended on the metal-sediment associated and sediment-to-water desorption rate. We exposed a detritivorous clam, Macoma inquinata, to clean and oil-contaminated detritus to determine the effects of the oil on metal accumulation. To measure the uptake of metals, clams were exposed to neutron activated detritus and the uptake of several isotopes (/sup 51/Cr, /sup 60/Co, /sup 152/Eu, /sup 59/Fe, /sup 46/Sc, and /sup 65/Zn) measured in the clams.
Application of ferrokinetic investigation for differential diagnosis in bone marrow hypoplasia and their clinical relevance.
Gupta, M; Roth, P; Werner, E; Kaltwasser, J P
In this study, erythropoietic activity of bone marrow has been evaluated by ferrokinetics. For that purpose, the data of radioiron disappearance from plasma and its ultimate incorporation in red blood cells after the injection of about 10 muCi of 59Fe tagged autologous plasma, were analysed and fitted to the sum of three exponentials, using a non-linear least square SAAM-25 program on UNIVAC-1108 computer. A function representing time-activity relationship, was constructed. The functional physiological model of iron metabolism, proposed by Cavill and Ricketts, was used to calculate various ferrokinetic parameters in terms of coefficients and exponents of the time-activity function. After identifying the parameters that could be used as indices of erythropoietic activity of bone marrow, the study was repeated in six patients after they had undergone myelostimulative therapy. A distinct correlation was found between ferrokinetic observations and clinical and biochemical findings. It has been demonstrated that in histologically diagnosed cases with bone marrow hypoplasia, a further differentiation between pure aplasia and those with hypoplasia together with ineffective erythropoiesis was possible. This discrimination which is clinically very important, is only possible by means of kinetic investigations. PMID:499222
Erythropoiesis in the aged mouse. I. Response to stimulation in vivo
Udupa, K.B.; Lipschitz, D.A.
Changes in erythropoiesis with age were studied by examining the hematocrit increase in response to hypoxia in aged mice and by assessing the change in erythropoiesis following the injection of erythropoietin in young and old polycythemic mice. The increase in hematocrit after exposure to hypoxia was more variable and generally lower in old mice than in young mice. When erythropoietin was injected into polycythemic animals, the increase in differentiated erythroid cells and /sup 59/Fe incorporation into erythroid marrow and peripheral blood cells was significantly lower in old mice than in young mice. In contrast to differentiated erythroid cells, there was less evidence of a reduced response to simulation of the more primitive erythroid progenitor cells of aged animals. The early undifferentiated erythroid progenitor, burst-forming units, did not decrease when either young or aged mice were made polycythemic, and no change following erythropoietin injection was noted. Polycythemia suppressed the late-differentiated erythroid progenitor, erythroid colony-forming units, to a greater extent in aged animals, but when erythropoietin was injected, the percent increase over the subsequent 24 hours was identical to that in young mice. These observations indicate a reduced erythropoietic capacity with age, the abnormality being most obvious in the more mature erythroid precursors.
Influence of n{sup +} and p{sup +} doping on the lattice sites of implanted Fe in Si
Silva, D. J.; Araújo, J. P.; Wahl, U.; Correia, J. G.
We report on the lattice location of implanted {sup 59}Fe in n{sup +}- and p{sup +}-type Si by means of emission channeling. We found clear evidence that the preferred lattice location of Fe changes with the doping of the material. While in n{sup +}-type Si Fe prefers displaced bond-centered (BC) sites for annealing temperatures up to 600 °C, changing to ideal substitutional sites above 700 °C, in p{sup +}-type Si, Fe prefers to be in displaced tetrahedral interstitial positions after all annealing steps. The dominant lattice sites of Fe in n{sup +}-type Si therefore seem to be well characterized for all annealing temperatures by the incorporation of Fe into vacancy-related complexes, either into single vacancies which leads to Fe on ideal substitutional sites, or multiple vacancies, which leads to its incorporation near BC sites. In contrast, in p{sup +}-type Si, the major fraction of Fe is clearly interstitial (near-T or ideal T) for all annealing temperatures. The formation and possible lattice sites of Fe in FeB pairs in p{sup +}-Si are discussed. We also address the relevance of our findings for the understanding of the gettering effects caused by radiation damage or P-diffusion, the latter involving n{sup +}-doped regions.
Cross Sections Needed for the Interpretation of Long-Lived and Short-Lived Cosmogenic Nuclide Production in Extraterrestrial Materials
NASA Astrophysics Data System (ADS)
Sisterson, J. M.; Beverding, A.; Kim, K. J.; Englert, P. A. J.; Jull, A. J. T.; Donahue, D. J.; Cloudt, S.; Castaneda, C.; Vincent, J.; Caffee, M. W.; Osazuwa, C. O.; Reedy, R. C.
Radionuclides produced by cosmic rays in extraterrestrial materials archive information that can be used to determine cosmic-ray fluxes and to study the history of the irradiated object. Long-lived radionuclides give information about the last ~5 Myr; short-lived radionuclides give information about recent events. To calculate the solar cosmic ray (SCR) flux from measured depth profiles for cosmogenic radionuclides produced in lunar rocks, accurate and precise cross section values for the production of these radionuclides from all relevant elements are needed. About 98% of SCR and ~87% of galactic cosmic rays (GCR) falling on extraterrestrial materials are protons. Cross section measurements were made using three proton accelerators to cover the energy range ~20 - 500 MeV. Thin target techniques used in the irradiations minimized the number of protons scattered out of the stack and the neutron production within the stack. After irradiation, the short-lived radionuclides e.g. 22Na, 7Be, 24Na, 54Mn, and 56Co were determined using gamma-ray spectroscopy. 14C, 10Be, and 26Al were determined using Accelerator Mass Spectrometry. Our main objective is to measure the production cross sections of long-lived radionuclides. We have reported new cross section values for making 10Be from O and 14C from O, Mg, Al, Si, Fe, and Ni [1,2]. Using these new results, better estimates for the solar proton flux over several time periods in the past were determined [3]. However, no single value for the SCR flux could explain the measured data from different time periods. Further cross section measurements are being made to verify that the values used in these estimates were accurate. Irradiations designed to give good cross section measurements for long-lived radionuclides also give good cross section measurements for short-lived radionuclides. Results will be presented for proton production cross sections of 22Na from Mg, Al and Si, and 54Mn and 56Co from Fe and Ni; some values at low
Moos, Torben
Iron is essential for virtually all types of cells and organisms. The significance of the iron for brain function is reflected by the presence of receptors for transferrin on brain capillary endothelial cells. The transport of iron into the brain from the circulation is regulated so that the extraction of iron by brain capillary endothelial cells is low in iron-replete conditions and the reverse when the iron need of the brain is high as in conditions with iron deficiency and during development of the brain. Whereas there is good agreement that iron is taken up by means of receptor-mediated uptake of iron-transferrin at the brain barriers, there are contradictory views on how iron is transported further on from the brain barriers and into the brain extracellular space. The prevailing hypothesis for transport of iron across the BBB suggests a mechanism that involves detachment of iron from transferrin within barrier cells followed by recycling of apo-transferrin to blood plasma and release of iron as non-transferrin-bound iron into the brain interstitium from where the iron is taken up by neurons and glial cells. Another hypothesis claims that iron-transferrin is transported into the brain by means of transcytosis through the BBB. This thesis deals with the topic "brain iron homeostasis" defined as the attempts to maintain constant concentrations of iron in the brain internal environment via regulation of iron transport through brain barriers, cellular iron uptake by neurons and glia, and export of iron from brain to blood. The first part deals with transport of iron-transferrin complexes from blood to brain either by transport across the brain barriers or by uptake and retrograde axonal transport in motor neurons projecting beyond the blood-brain barrier. The transport of iron and transport into the brain was examined using radiolabeled iron-transferrin. Intravenous injection of [59Fe-125]transferrin led to an almost two-fold higher accumulation of 59Fe than of
Characterization of transition carbides in quench and partitioned steel microstructures by Mössbauer spectroscopy and complementary techniques
Pierce, D. T.; Coughlin, D. R.; Williamson, D. L.; Clarke, K. D.; Clarke, A. J.; Speer, J. G.; De Moor, E.
Quenching and partitioning (Q&P) produces steel microstructures with martensite and austenite that exhibit promising property combinations for third generation advanced high strength steels. Understanding the kinetics of reactions that compete for available carbon, such as carbide formation, is critical for alloying and processing design and achieving austenite enrichment and retention during Q&P. Mössbauer effect spectroscopy (MES) was used to characterize Q&P microstructures in a 0.38C-1.54Mn-1.48Si wt.% steel after quenching to 225 °C and partitioning at 400 °C for 10 or 300 s, with an emphasis on transition carbides. The recoilless fraction for η-carbide was calculated and a correction for saturationmore » of the MES absorption spectrum was applied, making quantitative measurements of small amounts of η-carbide, including non-stoichiometric η-carbide, possible in Q&P microstructures. Complementary transmission electron microscopy confirmed the presence of η-carbides, and MES and X-ray diffraction were used to characterize the austenite. The amount of η-carbide formed during Q&P ranged from 1.4 to 2.4 at.%, accounting for a substantial portion (~24% to 41%) of the bulk carbon content of the steel. The amount (5.0 at.%) of η-carbide that formed after quenching and tempering (Q&T) at 400 °C for 300 s was significantly greater than after partitioning at 400 °C for 300 s (2.4 at.%), suggesting that carbon partitioning from martensite to austenite occurs in conjunction with η-carbide formation during Q&P in these specimens.« less
Calculations of Excitation Functions of Some Structural Fusion Materials for ( n, t) Reactions up to 50 MeV Energy
NASA Astrophysics Data System (ADS)
Tel, E.; Durgu, C.; Aktı, N. N.; Okuducu, Ş.
Fusion serves an inexhaustible energy for humankind. Although there have been significant research and development studies on the inertial and magnetic fusion reactor technology, there is still a long way to go to penetrate commercial fusion reactors to the energy market. Tritium self-sufficiency must be maintained for a commercial power plant. For self-sustaining (D-T) fusion driver tritium breeding ratio should be greater than 1.05. So, the working out the systematics of ( n, t) reaction cross sections is of great importance for the definition of the excitation function character for the given reaction taking place on various nuclei at different energies. In this study, ( n, t) reactions for some structural fusion materials such as 27Al, 51V, 52Cr, 55Mn, and 56Fe have been investigated. The new calculations on the excitation functions of 27Al( n, t)25Mg, 51V( n, t)49Ti, 52Cr( n, t)50V, 55Mn( n, t)53Cr and 56Fe( n, t)54Mn reactions have been carried out up to 50 MeV incident neutron energy. In these calculations, the pre-equilibrium and equilibrium effects have been investigated. The pre-equilibrium calculations involve the new evaluated the geometry dependent hybrid model, hybrid model and the cascade exciton model. Equilibrium effects are calculated according to the Weisskopf-Ewing model. Also in the present work, we have calculated ( n, t) reaction cross-sections by using new evaluated semi-empirical formulas developed by Tel et al. at 14-15 MeV energy. The calculated results are discussed and compared with the experimental data taken from the literature.
Experimental response function of a 3 in×3 in NaI(Tl) detector by inverse matrix method and effective atomic number of composite materials by gamma backscattering technique.
Kiran, K U; Ravindraswami, K; Eshwarappa, K M; Somashekarappa, H M
Response function of a widely used 3in×3in NaI(Tl) detector is constructed to correct the observed pulse height distribution. A 10×10 inverse matrix is constructed using 7 mono-energetic gamma sources ((57)Co, (203)Hg, (133)Ba, (22)Na, (137)Cs, (54)Mn and (65)Zn) which are evenly spaced in energy scale to unscramble the observed pulse height distribution. Bin widths (E)(1/2) of 0.01 (MeV)(1/2) are used to construct the matrix. Backscattered photons for an angle of 110° are obtained from a well-collimated 0.2146GBq (5.8mCi) (137)Cs gamma source for carbon, aluminium, iron, copper, granite and Portland cement. For each observed spectrum, single scattered spectrum is constructed analytically using detector parameters like FWHM, photo-peak efficiency and peak counts. Response corrected multiple scattered photons are extracted from the observed pulse height distribution by dividing the spectrum into a 10 ×1 matrix. Saturation thicknesses of carbon, aluminium, iron, copper, granite and Portland cement are found out. Variation of multiple scattered photons as a function of target thickness are simulated using MCNP code. A relationship between experimental and simulated saturation thicknesses of carbon, aluminium, iron and copper is obtained as a function of atomic number. Using this relation, effective atomic numbers of granite and Portland cement are obtained from interpolation method. Effective atomic numbers of granite and Portland cement are also obtained by theoretical equation using their elemental composition and comparing with the experimental and simulated results. PMID:26926377
Characterization of Neutron and Gamma Dose in the Irradiation Cell of Texas A and M University Research Reactor
Vasudevan, Latha; Reece, Warren D.; Chirayath, Sunil S.; Aghara, Sukesh
The Monte Carlo N-Particle (MCNP) code was used to develop a three dimensional computational model of the Texas A and M University Nuclear Science Center Reactor (NSCR) operating against the irradiation (dry cell) at steady state thermal power of 1 MW. The geometry of the NSCR core and the dry cell were modeled in detail. NSCR is used for a wide variety of experiments that utilizes the dry cell for neutron as well as gamma irradiation of samples. Information on the neutron and gamma radiation environment inside the dry cell is required to facilitate irradiation of samples. This paper presents the computed neutron flux, neutron and gamma dose rate, and foil reaction rates in the dry cell, obtained through MCNP5 simulations of the NSCR core. The neutron flux was measured using foil activation method and the reaction rates obtained from {sup 197}Au(n,{gamma}){sup 198}Au and {sup 54}Fe(n,p){sup 54}Mn were compared with the model and they showed agreement within {approx} 20%. The gamma dose rate at selected locations inside the dry cell was measured using radiochromic films and the results indicate slightly higher dose rates than predicted from the model. This is because the model calculated only prompt gamma dose rates during reactor operation while the radiochromic films measured gammas from activation products and fission product decayed gammas. The model was also used to calculate the neutron energy spectra for the energy range from 0.001 eV- 20 MeV. (authors)
Experimental setup and commissioning baseline study in search of time-variations in beta-decay half-lives
NASA Astrophysics Data System (ADS)
Goddard, Braden; Hitt, George W.; Solodov, Alexander A.; Bridi, Dorian; Isakovic, A. F.; El-Khazali, Reyad; Abulail, Ayman
Recently there have been a number of investigations into whether the decay constant of a radioactive isotope can be influenced by external factors, such as the Earth-Sun distance or Solar flare activity. Positive claims suggest that annual oscillations of ~0.1% and accelerations of ~0.4% in the relative activity of beta-emitters coincide with the Earth-Sun distance and solar flare activity, respectively. Results from replication experiments have so far been conflicting. The main criticism of the measurements used to trace and quantify these effects is that the data is of poor quality or limited in scope. Data have often been collected as part of short duration weekly calibration measurements, measured with a single type of low precision detector, only using one isotope, and having no environmental conditions information (temperature, pressure, humidity) accompanying the radiation measurements. This paper describes the setup of a series of counting experiments commissioned for addressing these criticisms. Six dedicated detector systems (four different types) measuring six different isotopes (14C, 54Mn, 60Co, 90Sr, 204Tl, and 226Ra) have been continuously collecting source activity synchronously with environmental data for a period of one month (April 2014). The results of this baseline commissioning study show that there are correlations between activity and environmental conditions for some detector types which are then quantified. The results also show that the one sigma counting uncertainties in all the detectors are less than 0.024% for a given 24 h period. After accounting for propagated uncertainties from corrections against correlations with environmental data, the ability to resolve 0.1% activity changes varies, from 8 min to 1.6 days, depending on the specific detector. All six experiments therefore, will have sufficient precision over the upcoming year to scrutinize claims of both annual activity oscillations and solar flare activity changes.
A radiotracer study of cerium and manganese uptake onto suspended particles in Chesapeake Bay
Moffett, J.W. )
The oxidation kinetics of Ce(III) and Mn(II) were studied in Chesapeake Bay in March and July 1990 to establish the role of water column redox processes in contributing to Ce anomalies observed in this estuary (SHOLKOVITZ and ELDERFIELD, 1988; SHOLKOVITZ et al., 1992). Oxidation was measured by adding Mn(II) and Ce(III) to freshly collected water samples as radiotracers and measuring their uptake onto the ambient suspended particle assemblage. Mn(II) oxidation was measured by following the uptake of [sup 54]Mn(II) onto suspended particles and utilizing protocols established by other workers to distinguish oxidation from Mn(II) adsorption. The same protocols were applicable to Ce(III), using [sup 139]Ce(III), and were supported by the use of [sup 152]Eu(III) as a nonredox reactive control. Specific rates of Ce(III) and MN(II) oxidation measured at a station in the North Bay (depth = 4 m) in July were 2016% per day and 4032% per day, respectively. In March, at the same station, the specific rate of Mn(II) of oxidation was only 1-% per day, and Ce(III) oxidation was undetectable. Both Ce(III) and Mn(II) oxidation processes were inhibited by azide, indicating that they were microbially mediated. The seasonal differences probably reflect strong seasonal variation in the abundance of Mn oxidizing bacteria. No Ce(III) oxidation occured in samples collected below the oxic/anoxic interface in July. The specific rates of oxidation for both elements were over 1000 times higher than those measured in the Sargasso Sea. However, the specific rates for Ce(III) and Mn(II) were very similar to each other. This fact, coupled with similar spatial and temporal trends for specific oxidation rates, suggests a common mechanism of oxidation of both elements which may be significant in a wide range of marine environments.
HETC96/MORSE calculations of activations in KEK beam stop and room by 500-MeV protons and comparisons with experiments
Fu, C.Y.; Gabriel, T.A.
The 1996 version of HETC has a pre-equilibrium reaction model to bridge the gap between the existing intranuclear-cascade and evaporation models. This code was used to calculate proton-induced activations, to calculate neutron fluxes for neutron energies above 19.6 MeV, and to write the neutron source for lower energies to be transported further by MORSE. For MORSE, the HILO cross section library was used for neutron transport for all detectors. Additionally for the {sup 197}Au(n, {gamma}) detector, the BUGLE96 library was used to study the effects of the low-lying {sup 57}Fe inelastic levels and the resonance self-shielding in iron. Neutron fluxes were obtained from the track-length estimator for detectors inside the beam stop and from the boundary-crossing estimator for detectors attached to the surfaces of the concrete walls. Activation cross sections given in JAERI-Data/Code are combined with the calculated neutron fluxes to get the saturated activities induced by neutrons. C/E values are too low (0.5) for Fe(N, {chi}){sup 54}Mn, close to unity for Cu(n, {chi}){sup 58}Co, and too high (6.0) for {sup 197}Au (n, {gamma}){sup 198}Au. It is difficult to interpret the disagreements because most of the activation cross sections are also calculated and their uncertainties are not known. However, the calculated results are in good agreement with those calculated by others using different codes. Calculated results for four of the ten activations reported here have not been done previously, and among the four, {sup 197}Au(n, {gamma}) is the most bothersome because its cross section is the most well known while the calculated activations for most detector locations are in largest disagreement with experiments.
Silicon decreases both uptake and root-to-shoot translocation of manganese in rice.
Che, Jing; Yamaji, Naoki; Shao, Ji Feng; Ma, Jian Feng; Shen, Ren Fang
Silicon (Si) is known to alleviate manganese (Mn) toxicity in a number of plant species; however, the mechanisms responsible for this effect are poorly understood. Here, we investigated the interaction between Si and Mn in rice (Oryza sativa) by using a mutant defective in Si uptake. Silicon alleviated Mn toxicity in the wild-type (WT) rice, but not in the mutant exposed to high Mn. The Mn concentration in the shoots was decreased, but that in the roots was increased by Si in the WT. In contrast, the Mn concentration in the roots and shoots was unaffected by Si in the mutant. Furthermore, Si supply resulted in an increased Mn in the root cell sap, decreased Mn in the xylem sap in the WT, but these effects of Si were not observed in the mutant. A short-term labelling experiment with (54)Mn showed that the uptake of Mn was similar between plants with and without Si and between WT and the mutant. However, Si decreased root-to-shoot translocation of Mn in the WT, but not in the mutant. The expression of a Mn transporter gene for uptake, OsNramp5, was unaffected by a short exposure (<1 d) to Si, but down-regulated by relatively long-term exposure to Si in WT. In contrast, the expression of OsNramp5 was unaffected by Si in the mutant. These results indicated that Si-decreased Mn accumulation results from both Si-decreased root-to-shoot translocation of Mn, probably by the formation of Mn-Si complex in root cells, and uptake by down-regulating Mn transporter gene. PMID:26733690
Manganese transporters Yfe and MntH are Fur-regulated and important for the virulence of Yersinia pestis
Craig, Susannah K.; Abney, Jennifer; Bobrov, Alexander G.; Kirillina, Olga; Mier, Ildefonso; Truszczynska, Helena; Fetherston, Jacqueline D.
Yersinia pestis has a flea-mammal-flea transmission cycle, and is a zoonotic pathogen that causes the systemic diseases bubonic and septicaemic plague in rodents and humans, as well as pneumonic plague in humans and non-human primates. Bubonic and pneumonic plague are quite different diseases that result from different routes of infection. Manganese (Mn) acquisition is critical for the growth and pathogenesis of a number of bacteria. The Yfe/Sit and/or MntH systems are the two prominent Mn transporters in Gram-negative bacteria. Previously we showed that the Y. pestis Yfe system transports Fe and Mn. Here we demonstrate that a mutation in yfe or mntH did not significantly affect in vitro aerobic growth under Mn-deficient conditions. A yfe mntH double mutant did exhibit a moderate growth defect which was alleviated by supplementation with Mn. No short-term energy-dependent uptake of 54Mn was observed in this double mutant. Like the yfeA promoter, the mntH promoter was repressed by both Mn and Fe via Fur. Sequences upstream of the Fur binding sequence in the yfeA promoter converted an iron-repressible promoter to one that is also repressed by Mn and Fe. To our knowledge, this is the first report identifying cis promoter elements needed to alter cation specificities involved in transcriptional repression. Finally, the Y. pestis yfe mntH double mutant had an ~133-fold loss of virulence in a mouse model of bubonic plague but no virulence loss in the pneumonic plague model. This suggests that Mn availability, bacterial Mn requirements or Mn transporters used by Y. pestis are different in the lungs (pneumonic plague) compared with systemic disease. PMID:22222497
Analysis of radiation environmental safety for China's Spallation Neutron Source (CSNS)
NASA Astrophysics Data System (ADS)
Wang, Qing-Bin; Wu, Qing-Biao; Ma, Zhong-Jian; Zhang, Qing-Jiang; Li, Nan; Wu, Jing-Min; Liu, Jian; Zhang, Gang
The China Spallation Neutron Source (CSNS) is going to be located in Dalang Town, Dongguan City in the Guangdong Province. In this paper we report the results of the parameters related with environment safety based on experiential calculations and Monte Carlo simulations. The main project of the accelerator is an under ground construction. On top there is a 0.5 m concrete and 5.0 m soil covering for shielding, which can reduce the dose out of the tunnel's top down to 0.2 μSv/h. For the residents on the boundary of the CSNS, the dose produced by skyshine, which is caused by the penetrated radiation leaking from the top of the accelerator, is no more than 0.68 μSv/a. When CSNS is operating normally, the maximal annual effective dose due to the emission of gas from the tunnel is 2.40×10-3 mSv/a to the public adult, and 2.29×10-3 mSv/a to a child, both values are two orders of magnitude less than the limiting value for control and management. CSNS may give rise to an activation of the soil and groundwater in the nearest tunnels, where the main productions are 3H, 7Be, 22Na, 54Mn, etc. But the specific activity is less than the exempt specific activity in the national standard GB13376-92. So it is safe to say that the environmental impact caused by the activation of soil and groundwater is insignificant. To sum up, for CSNS, as a powerful neutron source device, driven by a high-energy high-current proton accelerator, a lot of potential factors affecting the environment exist. However, as long as effective shieldings for protection are adopted and strict rules are drafted, the environmental impact can be kept under control within the limits of the national standard.
Histidine-stimulated divalent metal uptake in human and in the erythroleukaemic cell line HEL.92.1.7
Oakley, F; Horn, NM; Thomas, AL
The uptake of 65Zn by human erythrocytes was investigated in the presence of high (40 mm) and low (5 mm) concentrations of histidine and 0–500 μm cobalt, nickel, manganese and zinc. Varying concentrations of metal mono- and bis-histidine complexes will be formed and the inhibition of 65Zn uptake could be correlated with the calculated complex concentrations to investigate competition between metals. For each metal, the calculated concentrations of bis-histidine complex giving 50% inhibition of 65Zn uptake were similar at both 5 mm and 40 mm histidine. Manganese–bis-histidine appeared to have a much higher affinity for the binding site than the other metal–bis-histidine complexes, which had similar affinities to each other. Studies of the inhibition of histidine-stimulated 54Mn uptake by the addition of manganese confirmed that manganese–bis-histidine does act as a substrate for the transporter in a similar fashion to the other metals studied. In addition, human erythroleukaemic cells (HEL cells) were used as a model for erythroid precursor cells. l-histidine, but not d-histidine, stimulated 65Zn uptake in a saturable fashion. The other metals competed with zinc in a similar manner to that seen in erythrocytes, and the affinity for manganese–bis-histidine was much greater than for the bis-histidine complexes of the other three metals. Both the capacity for metal transport per cell, and the affinity of the transporter for the metal–bis-histidine complexes, were much greater in the HEL cells than in the erythrocyte. It is suggested that histidine-stimulated metal transport may play a role in the supply of metals to maturing erythroid cells. PMID:15486018
Cu(II) and Zn(II) ions alter the dynamics and distribution of Mn(II) in cultured chick glial cells
Wedler, F.C.; Ley, B.W. )
Previous studies revealed that Mn(II) is accumulated in cultured glial cells to concentrations far above those present in whole brain or in culture medium. The data indicated that Mn(II) moves across the plasma membrane into the cytoplasm by facilitated diffusion or counter-ion transport with Ca(II), then into mitochondria by active transport. The fact that 1-10 microM Mn(II) ions activate brain glutamine synthetase makes important the regulation of Mn(II) transport in the CNS. Since Cu(II) and Zn(II) caused significant changes in the accumulation of Mn(II) by glia, the mechanisms by which these ions alter the uptake and efflux of Mn(II) ions has been investigated systematically under chemically defined conditions. The kinetics of (54MN)-Mn(II) uptake and efflux were determined and compared under four different sets of conditions: no adducts, Cu(II) or Zn(II) added externally, and with cells preloaded with Cu(II) or Zn(II) in the presence and absence of external added metal ions. Zn(II) ions inhibit the initial velocity of Mn(II) uptake, increase total Mn(II) accumulated, but do not alter the rate or extent Mn(II) efflux. Cu(II) ions increase both the initial velocity and the net Mn(II) accumulated by glia, with little effect on rate or extent of Mn(II) efflux. These results predict that increases in Cu(II) or Zn(II) levels may also increase the steady-state levels of Mn(II) in the cytoplasmic fraction of glial cells, which may in turn alter the activity of Mn(II)-sensitive enzymes in this cell compartment.
Testing the Role of Cosmic Ray Reacceleration in the Galaxy
NASA Astrophysics Data System (ADS)
Connell, J. J.; Simpson, J. A.
Cosmic rays constitute a super-thermal gas of charged particles magnetically confined within the Galaxy. While propagating though the interstellar medium (ISM), cosmic ray nuclei undergo nuclear spallation reactions, producing both stable (i.e., Be and B) and unstable secondary nuclei. Consistent cosmic ray confinement times of ~ 20 Myr have been reported from measurements of the radioactive secondary isotopes (10) Be, (26) Al, (36) Cl and (54) Mn using data from the High Energy Telescope (HET) on the Ulysses spacecraft. It is generally accepted that Galactic cosmic rays of energy less than ~ 10(14) eV are accelerated by supernova shocks in the ISM. Reacceleration of existing cosmic rays in the ISM is implicit in interstellar shock acceleration models, but whether reacceleration plays a significant role in cosmic ray production and interstellar propagation is largely unknown. The abundances of secondary electron-capture isotopes provide a crucial test of cosmic ray reacceleration. Electron-capture is suppressed during interstellar propagation because cosmic ray nuclei are essentially stripped of their electrons. If, however, cosmic rays experience significant reacceleration, nuclei will have spent time at lower energies where electron pick-up, and hence electron capture, is more likely than at higher energies. Thus, electron capture secondary isotopes would be less abundant (and their daughters, more abundant) than otherwise predicted. The abundance ratio of (49) V to (51) V is a particularly sensitive test of this effect. The latest Ulysses HET data is used to address this problem. This research was supported in part by NASA/JPL Contract 955432 and NASA Grant NAG5-5179.
Cosmogenic nuclides in the Košice meteorite: Experimental investigations and Monte Carlo simulations
NASA Astrophysics Data System (ADS)
Povinec, Pavel P.; Masarik, Jozef; Sýkora, Ivan; KováčIk, Andrej; BeåO, Juraj; Meier, Matthias M. M.; Wieler, Rainer; Laubenstein, Matthias; PorubčAn, Vladimir
Results of nondestructive gamma-ray analyses of cosmogenic radionuclides (7Be, 22Na, 26Al, 46Sc, 48V, 54Mn, 56Co, 57Co, 58Co, and 60Co) in 19 fragments of the Košice meteorite are presented and discussed. The activities varied mainly with position of fragments in the meteoroid body, and with fluxes of cosmic-ray particles in the space affecting radionuclides with different half-lives. Monte Carlo simulations of the production rates of 60Co and 26Al compared with experimental data indicate that the pre-atmospheric radius of the meteoroid was 50 ± 5 cm. In two Košice fragments, He, Ne, and Ar concentrations and isotopic compositions were also analyzed. The noble-gas cosmic-ray exposure age of the Košice meteorite is 5-7 Myr, consistent with the conspicuous peak (or doublet peak) in the exposure age histogram of H chondrites. One sample likely contains traces of implanted solar wind Ne, suggesting that Košice is a regolith breccia. The agreement between the simulated and observed 26Al activities indicate that the meteoroid was mostly irradiated by a long-term average flux of galactic cosmic rays of 4.8 particles cm-2 s-1, whereas the short-lived radionuclide activities are more consistent with a flux of 7.0 protons cm-2 s-1 as a result of the low solar modulation of the galactic cosmic rays during the last few years before the meteorite fall.
Tritium monitoring of groundwater and surfaces
MacArthur, D.; Aamodt, P.; Bounds, J.; Koster, J.
There are numerous facilities, both within the US and in the rest of the world, within the complex of radiation laboratories and production plants where tritium has been released into the environment because of historic or ongoing mission-related operations. Many of environmental restoration projects have detected low levels of tritium contamination in local streams, ponds, and/or ground water. Typically these waters are moving or have the potential to move offsite and are viewed as a potential risk to the public and environment. Los Alamos National Laboratory will modify the well-proven long-range alpha detection (LRAD) technique for detection of ionizing radiation to optimize a system for detecting tritium in groundwater and other surfaces. The LRAD technique relies on detection of ionized air molecules rather than direct detection of ionizing radiation. The detected electrical current is proportional to the number of ionized air molecules present, which is in turn a measure of the amount of contamination present. Although this technique has been used commercially to measure alpha contamination on objects and surfaces, the technique is also ideal for monitoring low-energy beta particles. The authors have demonstrated beta detection using {sup 54}Mn, {sup 14}C, {sup 147}Pm, {sup 99}Tc, {sup 90}Sr, and {sup 36}Cl sources. Thus, the detector technology and detection of beta particles using this technology have both been demonstrated. The extreme short range of tritium beta particles necessitates an optimization of the detector system. In this paper, the authors will discuss these new designs.
Statistical properties of excited nuclei in the mass range 47 Less-Than-Or-Slanted-Equal-To A Less-Than-Or-Slanted-Equal-To 59
Zhuravlev, B. V. Lychagin, A. A. Titarenko, N. N.; Demenkov, V. G.; Trykova, V. I.
Level densities and their energy dependences for nuclei in the mass range of 47 {<=} A {<=} 59 were determined from the results obtained by measuring neutron-evaporation spectra in respective (p, n) reactions. The spectra of neutrons originating from the (p, n) reactions on {sup 47}Ti, {sup 48}Ti, {sup 49}Ti, {sup 53}Cr, {sup 54}Cr, {sup 57}Fe, and {sup 59}Co nuclei were measured in the proton-energy range of 7-11 MeV. These measurements were performed with the aid of a fast-neutron spectrometer by the time-of-flight method over the base of the EGP-15 pulsed tandem accelerator installed at the Institute for Physics and Power Engineering (Obninsk, Russia). A high resolution of the spectrometer and its stability in the time of flight made it possible to identify reliably discrete low-lying levels along with the continuum part of neutron spectra. Our measured data were analyzed within the statistical equilibrium and preequilibrium models of nuclear reactions. The respective calculations were performed with the aid of the Hauser-Feshbach formalismof statistical theory supplemented with the generalized model of a superfluid nucleus, the back-shifted Fermi gas model, and the Gilbert-Cameron composite formula for nuclear level densities. Nuclear level densities for {sup 47}V, {sup 48}V, {sup 49}V, {sup 53}Mn, {sup 54}Mn, {sup 57}Co, and {sup 59}Ni and their energy dependences were determined. The results are discussed and compared with available experimental data and with recommendations of model-based systematics.
Gamma-ray Sptectrometric Characterization of Overpacked CC 104/107 RH-TRU Wastes: Surrogate Tests
Hartwell, John Kelvin; Mc Ilwain, Michael Edward; Klann, R. T.
Development of the gamma-ray spectrometric technique termed GSAK (Gamma-Ray Spectrometry with Acceptable Knowledge) for the characterization of CC104/107 remote-handled transuranic (RH-TRU) wastes continued this year. Proof-of-principle measurements have been completed on the surrogate RH-TRU waste drums configured earlier this year. The GSAK technique uses conventional gamma-ray spectrometry to quantify the detectable fission product content of overpacked RH-TRU drums. These results are then coupled with the inventory report to characterize the waste drum content. The inventory report is based on process knowledge of the waste drum loading and calculations of the isotopic distribution in the spent fuel examined to generate the drummed wastes. Three RH-TRU surrogate drums were configured with encapsulated EBR-II driver fuel rod segments arranged in the surrogate drum assemblies. Segment-specific inventory calculations initially specified the radionuclide content of the fuel segments and thus the surrogate drums. Radiochemical assays performed on representative fuel element segments identified a problem in the accuracy of some of the fission and activation product inventory values and provided a basis for adjustment of the specified surrogate drum inventories. The three waste drum surrogates, contained within their 8.9 cm (3.5 inch) thick steel overpacks, were analyzed by gamma-ray spectrometry at the TREAT facility at Argonne National Laboratory-West. Seven fission and activation product radionuclides (54Mn, 60Co, 125Sb, 134Cs, 137Cs, 144CePr, and 154Eu) were reliably detected. The gamma-ray spectral accuracy was very good. In all cases, a two-sigma error bar constructed about the measured value included the actual drum activity.
Gamma-Ray Spectrometric Characterization of Overpacked CC104/107 RH-TRU Wastes: Surrogate Tests
J. K. Hartwell; R. T. Klann; M. E. McIlwain
Development of the gamma-ray spectrometric technique termed GSAK (Gamma-Ray Spectrometry with Acceptable Knowledge) for the characterization of CC104/107 remote-handled transuranic (RH-TRU) wastes continued this year. Proof-of-principle measurements have been completed on the surrogate RH-TRU waste drums configured earlier this year. The GSAK technique uses conventional gamma-ray spectrometry to quantify the detectable fission product content of overpacked RH-TRU drums. These results are then coupled with the inventory report to characterize the waste drum content. The inventory report is based on process knowledge of the waste drum loading and calculations of the isotopic distribution in the spent fuel examined to generate the drummed wastes. Three RH-TRU surrogate drums were configured with encapsulated EBR-II driver fuel rod segments arranged in the surrogate drum assemblies. Segment-specific inventory calculations initially specified the radionuclide content of the fuel segments and thus the surrogate drums. Radiochemical assays performed on representative fuel element segments identified a problem in the accuracy of some of the fission and activation product inventory values and provided a basis for adjustment of the specified surrogate drum inventories. The three waste drum surrogates, contained within their 8.9 cm (3.5 inch) thick steel overpacks, were analyzed by gamma-ray spectrometry at the TREAT facility at Argonne National Laboratory-West. Seven fission and activation product radionuclides ({sup 54}Mn, {sup 60}Co, {sup 125}Sb, {sup 134}Cs, {sup 137}Cs, {sup 144}CePr, and {sup 154}Eu) were reliably detected. The gamma-ray spectral accuracy was very good. In all cases, a two-sigma error bar constructed about the measured value included the actual drum activity.
Evaluation of equivalent dose from neutrons and activation products from a 15-MV X-ray LINAC.
Israngkul-Na-Ayuthaya, Isra; Suriyapee, Sivalee; Pengvanich, Phongpheath
A high-energy photon beam that is more than 10 MV can produce neutron contamination. Neutrons are generated by the [γ,n] reactions with a high-Z target material. The equivalent neutron dose and gamma dose from activation products have been estimated in a LINAC equipped with a 15-MV photon beam. A Monte Carlo simulation code was employed for neutron and photon dosimetry due to mixed beam. The neutron dose was also experimentally measured using the Optically Stimulated Luminescence (OSL) under various conditions to compare with the simulation. The activation products were measured by gamma spectrometer system. The average neutron energy was calculated to be 0.25 MeV. The equivalent neutron dose at the isocenter obtained from OSL measurement and MC calculation was 5.39 and 3.44 mSv/Gy, respectively. A gamma dose rate of 4.14 µSv/h was observed as a result of activations by neutron inside the treatment machine. The gamma spectrum analysis showed (28)Al, (24)Na, (54)Mn and (60)Co. The results confirm that neutrons and gamma rays are generated, and gamma rays remain inside the treatment room after the termination of X-ray irradiation. The source of neutrons is the product of the [γ,n] reactions in the machine head, whereas gamma rays are produced from the [n,γ] reactions (i.e. neutron activation) with materials inside the treatment room. The most activated nuclide is (28)Al, which has a half life of 2.245 min. In practice, it is recommended that staff should wait for a few minutes (several (28)Al half-lives) before entering the treatment room after the treatment finishes to minimize the dose received. PMID:26265661
Characterization of transition carbides in quench and partitioned steel microstructures by Mössbauer spectroscopy and complementary techniques
Pierce, D. T.; Coughlin, D. R.; Williamson, D. L.; Clarke, K. D.; Clarke, A. J.; Speer, J. G.; De Moor, E.
Quenching and partitioning (Q&P) produces steel microstructures with martensite and austenite that exhibit promising property combinations for third generation advanced high strength steels. Understanding the kinetics of reactions that compete for available carbon, such as carbide formation, is critical for alloying and processing design and achieving austenite enrichment and retention during Q&P. Mössbauer effect spectroscopy (MES) was used to characterize Q&P microstructures in a 0.38C-1.54Mn-1.48Si wt.% steel after quenching to 225 °C and partitioning at 400 °C for 10 or 300 s, with an emphasis on transition carbides. The recoilless fraction for η-carbide was calculated and a correction for saturation of the MES absorption spectrum was applied, making quantitative measurements of small amounts of η-carbide, including non-stoichiometric η-carbide, possible in Q&P microstructures. Complementary transmission electron microscopy confirmed the presence of η-carbides, and MES and X-ray diffraction were used to characterize the austenite. The amount of η-carbide formed during Q&P ranged from 1.4 to 2.4 at.%, accounting for a substantial portion (~24% to 41%) of the bulk carbon content of the steel. The amount (5.0 at.%) of η-carbide that formed after quenching and tempering (Q&T) at 400 °C for 300 s was significantly greater than after partitioning at 400 °C for 300 s (2.4 at.%), suggesting that carbon partitioning from martensite to austenite occurs in conjunction with η-carbide formation during Q&P in these specimens.
Evaluation of equivalent dose from neutrons and activation products from a 15-MV X-ray LINAC
Israngkul-Na-Ayuthaya, Isra; Suriyapee, Sivalee; Pengvanich, Phongpheath
A high-energy photon beam that is more than 10 MV can produce neutron contamination. Neutrons are generated by the [γ,n] reactions with a high-Z target material. The equivalent neutron dose and gamma dose from activation products have been estimated in a LINAC equipped with a 15-MV photon beam. A Monte Carlo simulation code was employed for neutron and photon dosimetry due to mixed beam. The neutron dose was also experimentally measured using the Optically Stimulated Luminescence (OSL) under various conditions to compare with the simulation. The activation products were measured by gamma spectrometer system. The average neutron energy was calculated to be 0.25 MeV. The equivalent neutron dose at the isocenter obtained from OSL measurement and MC calculation was 5.39 and 3.44 mSv/Gy, respectively. A gamma dose rate of 4.14 µSv/h was observed as a result of activations by neutron inside the treatment machine. The gamma spectrum analysis showed 28Al, 24Na, 54Mn and 60Co. The results confirm that neutrons and gamma rays are generated, and gamma rays remain inside the treatment room after the termination of X-ray irradiation. The source of neutrons is the product of the [γ,n] reactions in the machine head, whereas gamma rays are produced from the [n,γ] reactions (i.e. neutron activation) with materials inside the treatment room. The most activated nuclide is 28Al, which has a half life of 2.245 min. In practice, it is recommended that staff should wait for a few minutes (several 28Al half-lives) before entering the treatment room after the treatment finishes to minimize the dose received. PMID:26265661
Strontium, barium, and manganese metabolism in isolated presynaptic nerve terminals
Rasgado-Flores, H.; Sanchez-Armass, S.; Blaustein, M.P.; Nachshen, D.A.
To gain insight into the mechanisms by which the divalent cations Sr, Ba, and Mn affect neurotransmitter release from presynaptic nerve terminals, the authors examined the sequestration of these cations, ion comparison to Ca, by mitochondrial and nonmitochondrial organelles and the extrusion of these cations from isolated nerve terminals. Sequestration was studied in synaptosomes made leaky to small ions by treatment with saponin; efflux was examined in intact synaptosomes that were preloaded with the divalent cations by incubation in depolarizing (K rich) media. The selectivity sequence for ATP-dependent mitochondrial uptake that they observed was Mn>>Ca>Sr>>Ba, whereas that for the SER was Ca greater than or equal to Mn>Sr>>Ba. When synaptosomes that were preloaded with divalent cations were incubated in Na- and Ca-free media, there was little efflux of /sup 45/Ca, /sup 133/Ba, /sup 85/Sr, or /sup 54/Mn. When the incubation was carried out in media containing Na without Ca, there was substantial stimulation of Ca and Sr efflux, but only slight stimulation of Ba or Mn efflux. In Na-free media, the addition of 1 mM Ca promoted the efflux of all four divalent cations, probably via Ca-divalent cation exchange. In summary, the sequestration and extrusion data suggest that, with equal loads, Mn will be buffered to the greatest extent, whereas Ba will be least well buffered. These results may help to explain why Mn has a very long-lasting effect on transmitter release, while the effect of Sr is much briefer.
Cosmogenic radionuclides and mineralogical properties of the Chelyabinsk (LL5) meteorite: What do we learn about the meteoroid?
NASA Astrophysics Data System (ADS)
Povinec, Pavel P.; Laubenstein, Matthias; Jull, A. J. Timothy; FerrièRe, Ludovic; BrandstäTter, Franz; Sýkora, Ivan; Masarik, Jozef; BeåO, Juraj; KováčIk, Andrej; Topa, Dan; Koeberl, Christian
On February 15, 2013, after the observation of a brilliant fireball and a spectacular airburst over the southern Ural region (Russia), thousands of stones fell and were rapidly recovered, bringing some extremely fresh material for scientific investigations. We undertook a multidisciplinary study of a dozen stones of the Chelyabinsk meteorite, including petrographic and microprobe investigations to unravel intrinsic characteristics of this meteorite. We also study the short and long-lived cosmogenic radionuclides to characterize the initial meteoroid size and exposure age. Petrographic observations, as well as the mineral compositions obtained by electron microprobe analyses, allow us to confirm the classification of the Chelyabinsk meteorite as an LL5 chondrite. The fragments studied, a few of which are impact melt rocks, contain abundant shock melt veins and melt pockets. It is likely that the catastrophic explosion and fragmentation of the Chelyabinsk meteoroid into thousands of stones was in part determined by the initial state of the meteoroid. The radionuclide results obtained show a wide range of concentrations of 14C, 22Na, 26Al, 54Mn, 57Co, 58Co, and 60Co, which indicate that the pre-atmospheric object had a radius >5 m, consistent with other size estimates based on the magnitude of the airburst caused by the atmospheric entry and breakup of the Chelyabinsk meteoroid. Considering the observed 26Al activities of the investigated samples, Monte Carlo simulations, and taking into account the 26Al half-life (0.717 Myr), the cosmic-ray exposure age of the Chelyabinsk meteorite is estimated to be 1.2 ± 0.2 Myr. In contrast to the other radionuclides, 14C showed a very large range only consistent with most samples having been exposed to anthropogenic sources of 14C, which we associate with radioactive contamination of the Chelyabinsk region by past nuclear accidents and waste disposal, which has also been confirmed by elevated levels of anthropogenic 137Cs and
Decline of radionuclides in the nearshore environment following nuclear reactor closure: A U.K. case study
Cundy, A.B.; Croudace, I.W.; Warwick, P.E.; Bains, M.E.D.
Radioactive discharges from nuclear facilities are frequently made into the marine environment and their fate during and after cessation of discharges is a matter of interest and concern. This study examines the decline of the radionuclides {sup 60} and {sup 65}Zn along the southern UK. coast, over the per 1988--1998, following the closure of the steam-generating heavy water (SGHW) reactor at AEA Winfrith, Dorset, UK. {sup 60}Co and {sup 65}Zn (and other activation products such as {sup 63}Ni and {sup 55}Fe) were widely dispersed in the marine environment off the central south coast of England, due to authorized releases from AEA Winfrith. Significant interaction occurred with clay-rich sediments and biota. A general exponential decline in {sup 60}Co activities (and in {sup 65}Zn activity) is found in intertidal mudflat sediments, seaweed and marine fauna in different areas along the south coast following closure of the reactor in 1990. Effective half-lives are determined which vary from 1 to 4 years in surface sediments ({sup 60}Co only), 1--4 years in seaweed and 0.5--2.5 years in crustaceans, bivalves and molluscs. Physical mixing and bioturbation largely control the rate at which {sup 60}Co declines in surface sediments. Both {sup 60}Co and {sup 65}Zn show a relatively slow rate of decline in seaweed and in marine fauna, showing that even after the virtual cessation of discharge from nuclear facilities, contamination of these organisms may persist for a number of years, albeit at reduced activities. Reasons for this persistence are likely to include absorption of radionuclides from sediment, and release and recycling of radionuclides via breakdown of contaminated organic material.
Vortex focusing of ions produced in corona discharge.
Kolomiets, Yuri N; Pervukhin, Viktor V
Completeness of the ion transportation into an analytical path defines the efficiency of ionization analysis techniques. This is of particular importance for atmospheric pressure ionization sources like corona discharge, electrospray, ionization with radioactive ((3)H, (63)Ni) isotopes that produce nonuniform spatial distribution of sample ions. The available methods of sample ion focusing are either efficient at reduced pressure (~1Torr) or feature high sample losses. This paper deals with experimental research into atmospheric pressure focusing of unipolar (positive) ions using a highly swirled air stream with a well-defined vortex core. Effects of electrical fields from corona needle and inlet capillary of mass spectrometer on collection efficiency is considered. We used a corona discharge to produce an ionized unipolar sample. It is shown experimentally that with an electrical field barrier efficient transportation and focusing of an ionized sample are possible only when a metal plate restricting the stream and provided with an opening covered with a grid is used. This gives a five-fold increase of the transportation efficiency. It is shown that the electric field barrier in the vortex sampling region reduces the efficiency of remote ionized sample transportation two times. The difference in the efficiency of light ion focusing observed may be explained by a high mobility and a significant effect of the electric field barrier upon them. It is possible to conclude based on the experimental data that the presence of the field barrier narrows considerably (more than by one and half) the region of the vortex sample ion focusing. PMID:23618173
Assessment of Hard-to-Detect Radionuclide Levels in Decommissioning Waste From the Bohunice NPP-A1, Slovakia, for Clearance and Disposal Purposes
Slavik, O.; Moravek, J.; Stubna, M.
For assessments of hard-to-detect radionuclides (HD-RN) contents in various type of radwastes at the NPP-A1, available empirical data referenced to 137Cs (actinides, 90Sr, 99Tc, 63Ni, 14C) and the theoretical assessment for the remaining HD-RN using calculated RN inventory and a simple model with effective relative (137Cs) spent fuel release fractions was applied. The analytical data of extended radiochemical analysis for the existing available operational radwaste forms have been reviewed for this purpose. 137Cs, 90Sr and 241Am were set up as release markers for partial spent fuel release groups of HD-RNs within which the total fractions of HD-RN released to the operational radwastes were assumed to be constant. It was shown by the assessment carried out that 137Cs and HD-RNs 129I, 99Tc, and partly 79Se and 14C are the main contributors to the disposal dose limit for the radioactive concentrate at NPP A-1. In the case of the radioactive sludge from the operational radwaste system the role of predominant dose contributors belongs to actinides 239,240Pu and 241Am. In the case of clearance of radioactive material from the NPP-A1 site, only the reference radionuclide, 137Cs was predicted to be the most dominant dose contributor. In all of these cases the estimated contributions of other hard-to-detect radionuclides to respective disposal or release dose limit are lower by 2 and more orders of magnitude. As a lesson learned, the most attention is proposed to focus on the control and measurement of the critical HD-RNs indicated by the assessment. For the control of less important HD-RNs, the developed release coefficient method is sufficient to be applied.
Fragmentation, auto-modification and post ionisation proton bound dimer ion formation: the differential mobility spectrometry of low molecular weight alcohols.
Ruszkiewicz, D M; Thomas, C L P; Eiceman, G A
Differential mobility spectrometry (DMS) is currently being used for environmental monitoring of space craft atmospheres and has been proposed for the rapid assessment of patients at accident and emergency receptions. Three studies investigated hitherto undescribed complexity in the DMS spectra of methanol, ethanol, propan-1-ol and butan-1-ol product ions formed from a (63)Ni ionisation source. 54 000 DMS spectra obtained over a concentration range of 0.01 mg m(-3)(g) to 1.80 g m(-3)(g) revealed the phenomenon of auto-modification of the product ions. This occurred when the neutral vapour concentration exceeded the level required to induce a neutral-ion collision during the low field portion of the dispersion field waveform. Further, post-ionisation cluster-ion formation or protonated monomer/proton bound dimer inter-conversion within the ion-filter was indicated by apparent shifts in the values of the protonated monomer compensation field maximum; indicative of post-ionisation conversion of the protonated monomer to a proton-bound dimer. APCI-DMS-quadrupole mass spectrometry studies enabled the ion dissociation products from dispersion-field heating to be monitored and product ion fragmentation relationships to be proposed. Methanol was not observed to dissociate, while propan-1-ol and butan-1-ol underwent dissociation reactions consistent with dehydration processes that led ultimately to the generation of what is tentatively assigned as a cyclo-C3H3(+) ion (m/z 39) and hydrated protons. Studies of the interaction of ion filter temperature with dispersion-field heating of product ions isolated dissociation/fragmentation product ions that have not been previously described in DMS. The implications of these combined findings with regard to data sharing and data interpretation were highlighted. PMID:27227997
Transport of explosives I: TNT in soil and its equilibrium vapor
NASA Astrophysics Data System (ADS)
Baez, Bibiana; Correa, Sandra N.; Hernandez-Rivera, Samuel P.; de Jesus, Maritza; Castro, Miguel E.; Mina, Nairmen; Briano, Julio G.
Landmine detection is an important task for military operations and for humanitarian demining. Conventional methods for landmine detection involve measurements of physical properties. Several of these methods fail on the detection of modern mines with plastic enclosures. Methods based on the detection signature explosives chemicals such as TNT and DNT are specific to landmines and explosive devices. However, such methods involve the measurements of the vapor trace, which can be deceiving of the actual mine location because of the complex transport phenomena that occur in the soil neighboring the buried landmine. We report on the results of the study of the explosives subject to similar environmental conditions as the actual mines. Soil samples containing TNT were used to study the effects of aging, temperature and moisture under controlled conditions. The soil used in the investigation was Ottawa sand. A JEOL GCMate II gas chromatograph +/- mass spectrometer coupled to a Tunable Electron Energy Monochromator (TEEM-GC/MS) was used to develop the method of analysis of explosives under enhanced detection conditions. Simultaneously, a GC with micro cell 63Ni, Electron Capture Detector (μECD) was used for analysis of TNT in sand. Both techniques were coupled with Solid-Phase Micro Extraction (SPME) methodology to collect TNT doped sand samples. The experiments were done in both, headspace and immersion modes of SPME for sampling of explosives. In the headspace experiments it was possible to detect appreciable TNT vapors as early as 1 hour after of preparing the samples, even at room temperature (20 °C). In the immersion experiments, I-SPME technique allowed for the detection of concentrations as low as 0.010 mg of explosive per kilogram of soil.
Tillage and N-source influence soil-emitted nitrous oxide in the Alberta Parkland region
Lemke , R L.; Izaurralde, R Cesar C.; Nyborg, M.; Solberg, E D.
Zero tillage systems are receiving attention as possible strategies for sequestering atmospheric carbon. This benefit may be offset by increased N2O emissions, which have been reported for soils under zero tillage (ZT) compared to those under more intensive tillage (IT). Comparisons of N2O emissions from the two systems have been restricted to the growing season, but substantial losses of N2O have been reported during spring thaw events in many regions. Inorganic and organic additions of nitrogen and fallowing have also been shown to increase levels of soil-emitted N2O. The objectives for this study were: (i) to confirm that losses of N2O are higher under ZT than under IT in Alberta Parkland agroecosystems; (ii) to compare the relative influence of urea fertilizer (56 or 100 kg N h--1), field pea residue (dry matter at 5 Mg h--1), sheep manure (dry matter at 40 Mg h--1) additions, and fallow on total N2O losses; and (iii) to investigate possible interactions between fertility and tillage treatments. Gas samples were collected using vented soil covers at three sites near Edmonton, Alberta during 1993, 1994, and 1995. Gas samples were analyzed using a gas chromatograph equipped with a 63Ni electron capture detector. Estimated annual N2O loss ranged from 0.1 to 4.0 kg N ha-1. Emissions during summer were slightly higher, similar, or lower on ZT compared to those under IT, but were consistently lower on ZT plots during spring thaw. Combined estimates (spring plus summer) of N2O loss under ZT were equal to or lower than those under IT. Highest overall losses were observed on fallow plots, followed by fertilizer, pea residue, and then either manure or control plots. We conclude that ZT management systems have potential for reducing agricultural greenhouse gas emissions in the Alberta Parkland region.
An evaluation of nickel toxicity to Ceriodaphnia dubia and Daphnia magna in a contaminated stream and in laboratory tests
Kszos, L.A.; Stewart, A.J.; Taylor, P.A. )
Seven-day tests with Ceriodaphnia dubia were used to document ambient toxicity in two industrially contaminated streams in southeastern Tennessee. Low survival of Ceriodaphnia dubia was linked to concentrations of Ni below EPA water quality criteria. A toxicity identification evaluation consisting of Ceriodaphnia dubia, Daphnia magna, and Pimephales promelas toxicity tests with Ni, chemical analyses, and experiments with a Ni-selective resin were used to show that Ni was the primary toxicant in one of the streams. Nickel nitrate and Ni chloride were both extremely toxic to Ceriodaphnia dubia but were not very toxic to Pimephales promelas: Ni at a concentration of 7.5 [mu]g/l was lethal to Ceriodaphnia dubia within 7 d, but 16 mg/L Ni did not reduce survival or growth of Pimephales promelas. When dilution water with a hardness of 177 mg/L was used, 15.0 [mu]g/L killed all the Ceriodaphnia dubia in 7 d. Daphnia magna was less sensitive than Ceriodaphnia dubia to Ni: a concentration of 40 [mu]g/L significantly reduced fecundity but not survival in 21 d. In stream water containing 49 [mu]g/L Ni, 100% mortality of Ceriodaphnia dubia occurred in 7 d, but 70% of the Daphnia magna survived for 14 d. When the Ni in the stream water was reduced to 10 [mu]g/L with the resin, 60% of the Ceriodaphnia dubia lived for 7 d and all the animals reproduced; survival and reproduction of Daphnia magna remained high for all 14 d. Experiments with [sup 63]Ni showed that both species accumulated similar amounts of Ni, so the difference in toxicity was not a result of Ni uptake. The high sensitivity of Ceriodaphnia dubia to Ni and the lower than expected reduction in Ni toxicity to Ceriodaphnia dubia with increasing hardness have important implications for effluent and ambient testing and toxicity reduction efforts.
Honeycomb Betavoltaic Battery for Space Applications
NASA Astrophysics Data System (ADS)
Lee, Jin R.; Ulmen, Ben; Miley, George H.
Radioisotopic batteries offer advantages relative to conventional chemical batteries for applications requiring a long lifetime with minimum maintenance. Thus, thermoelectric type cells fueled with Pu have been used extensively on NASA space missions. The design for a small beta battery using nickel-63 (Ni-63) and a vacuum direct collection method is described here. A honeycomb nickel wire structure is employed to achieve bi-directional direct collection by seeding Ni-63 onto honeycomb shaped wires that will provide structural support as well. The battery design is intended to power low power electronics and distribute power needs in space probes as well as space colonies. Ni-63 is chosen as the source emitter because it has a long half-life and ease of manufacturing. The use of vacuum is especially well mated to space use; hence, vacuum insulation is employed to gain a higher efficiency than prior beta batteries with a dielectric insulator. A unique voltage down-converter is incorporated to efficiently reduce the inherent output voltage from 17.4 kV to ~17.4 V. This converter operates like a ``reverse'' Marx circuit where capacitor charging occurs in series but the discharge is in parallel. The reference battery module described here is about 100 cm×100 cm×218 cm and has a power of ~10 W with a conversion efficiency of ~15.8%. These modules can be stacked for higher powers and are very attractive for various applications in space colonization due to their long life (half-life for Ni-63~100 yrs) and low maintenance.
GC/MS on an LC/MS instrument using atmospheric pressure photoionization
NASA Astrophysics Data System (ADS)
McEwen, Charles N.
Atmospheric pressure (AP) GC/MS was first introduced by Horning et al. [E.C. Horning, M.G. Horning, D.I. Carroll, I. Dzidic, R.N. Stillwell, Anal. Chem. 45 (1973) 936] using 63Ni as a beta-emitter for ionization. Because, at the time special instrumentation was required, the technique was only applied with consistency to negative ion environmental studies where high sensitivity was required [T. Kinouchi, A.T.L. Miranda, L.G. Rushing, F.A. Beland, W.A. Korfmacher, J. High Resolut. Chromatogr., Chromatogr. Commun. 13 (1990) 281]. Currently, AP ion sources are commonly available on LC/MS instruments and recently a method was reported for converting an AP-LC/MS ion source to a combination AP-LC/MS:GC/MS source [C.N. McEwen, R.G. McKay, J. Am. Soc. Mass Spectrom. 16 (2005) 1730]. Here, we report the use of atmospheric pressure photoionization (APPI) with GC/MS and compare this to AP chemical ionization (APCI) GC/MS and electron ionization (EI) GC/MS. Using a nitrogen purge gas, we observe excellent chromatographic resolution and abundant molecular M+ and MH+ ions as well as structurally significant fragment ions. Comparison of a 9.8 eV UV lamp with a 10.6 eV lamp, as expected, shows that the higher energy lamp gives more universal ionization and more fragment ions than the lower energy lamp. While there are clear differences in the fragment ions observed by APPI-MS versus EI-MS, there are also similarities. As might be expected from the ionization mechanism, APPI ionization is similar to low energy EI. These odd electron fragment ions are useful in identifying unknown compounds by comparison to mass spectra in computer libraries.
Identification and Characterization of the Nickel Uptake System for Urease Biogenesis in Streptococcus salivarius 57.I
Chen, Yi-Ywan M.; Burne, Robert A.
Ureases are multisubunit enzymes requiring Ni2+ for activity. The low pH-inducible urease gene cluster in Streptococcus salivarius 57.I is organized as an operon, beginning with ureI, followed by ureABC (structural genes), and ureEFGD (accessory genes). Urease biogenesis also requires a high-affinity Ni2+ uptake system. By searching the partial genome sequence of a closely related organism, Streptococcus thermophilus LMG18311, three open reading frame (ORFs) homologous to those encoding proteins involved in cobalamin biosynthesis and cobalt transport (cbiMQO) were identified immediately 3′ to the ure operon. To determine whether these genes were involved in urease biogenesis by catalyzing Ni2+ uptake in S. salivarius, regions 3′ to ureD were amplified by PCRs from S. salivarius by using primers identical to the S. thermophilus sequences. Sequence analysis of the products revealed three ORFs. Reverse transcriptase PCR was used to demonstrate that the ORFs are transcribed as part of the ure operon. Insertional inactivation of ORF1 with a polar kanamycin marker completely abolished urease activity and the ability to accumulate 63Ni2+ during growth. Supplementation of the growth medium with NiCl2 at concentrations as low as 2.5 μM partially restored urease activity in the mutant. Both wild-type and mutant strains showed enhanced urease activity when exogenous Ni2+ was provided at neutral pH. Enhancement of urease activity by adding nickel was regulated at the posttranslational level. Thus, ORF1, ORF2, and ORF3 are part of the ure operon, and these genes, designated ureM, ureQ, and ureO, respectively, likely encode a Ni2+-specific ATP-binding cassette transporter. PMID:14617641
Photochemistry of limonene secondary organic aerosol studied with chemical ionization mass spectrometry
NASA Astrophysics Data System (ADS)
Pan, Xiang
Limonene is one of the most abundant monoterpenes in the atmosphere. Limonene easily reacts with gas-phase oxidants in air such as NO3, ozone and OH. Secondary organic aerosol (SOA) is formed when low vapor pressure products condense into particles. Chemicals in SOA particles can undergo further reactions with oxidants and with solar radiation that significantly change SOA composition over the course of several days. The goal of this work was to characterize radiation induced reaction in SOA. To perform experiments, we have designed and constructed an Atmospheric Pressure Chemical Ionization Mass Spectrometer (APCIMS) coupled to a photochemical cell containing SOA samples. In APCIMS, (H2O)nH 3O+ clusters are generated in a 63Ni source and react with gaseous organic analytes. Most organic chemicals are not fragmented by the ionization process. We have focused our attention on limonene SOA prepared in two different ways. The first type of SOA is produced by oxidation of limonene by ozone; and the second type of SOA is formed by the NO3-induced oxidation of limonene. They model the SOA formed under daytime and nighttime conditions, respectively. Ozone initiated oxidation is the most important chemical sink for limonene both indoors, where it is used for cleaning purposes, and outdoors. Terpenes are primarily oxidized by reactions with NO3 at night time. We generated limonene SOA under different ozone and limonene concentrations. The resulting SOA samples were exposed to wavelength-tunable radiation in the UV-Visible range between 270 nm and 630 nm. The results show that the photodegradation rates strongly depend on radiation wavelengths. Gas phase photodegradation products such as acetone, formaldehyde, acetaldehyde, and acetic acid were shown to have different production rates for SOA formed in different concentration conditions. Even for SOA prepared under the lowest concentrations, the SOA photodegradation was efficient. The conclusion is that exposure of SOA to
Biomineral microstructures in ferromanganese nodules: evidence of the biological and abiogenous origin
NASA Astrophysics Data System (ADS)
Lysyuk, G. N.
Manganese oxides, which are widespread and of great practical importance, are formed and transformed by the active role of microorganisms. Manganese aggregates occur as both crystallized varieties and disordered fine-grained phases with significant ore grade and up to 50-60 vol % of X-ray amorphous components. X-ray amorphous nanosizedMn oxides in Fe-Mn nodules from the Pacific Ocean floor were examined from the standpoint of their biogenic origin. SEM examination showed abundant mineralized biofilms on the studied samples. The chemical composition of bacterial mass is as follows (wt %): 28.34 MnO, 17.14 Fe2O3, 7.11 SiO2, 2.41 CaO, 17.90 TiO2, 1.74Na2O,1.73 A12O3,1.30 MgO, 1.25P2O5,1.25 SO3,0.68 CoO, 0.54 CuO, 0.53 NiO, and 0.50 K2O. The chemical composition of fossilized cyanobacterial mats within the interlayer space of nodules is as follows (wt %): 48.35 MnO, 6.23 Fe2O3, 8.76 MgO, 5.05 A12O3, 4.45 SiO2, 3.63 NiO, 2.30 Na2O, 2.19 CuO, 1.31 CaO, and 0.68 K2O is direct evidence for participation of bacteria in Mn oxide formation. This phase consists of mineralized glycocalix consisting of nanosized flakes of todorokite. Native metals (Cu, Fe, and Zn) as inclusions 10-20 μm in size were identified in ferromanganese nodules as well. The formation of native metals can be explained by their crystallization at highly reducing conditions maintained by organic matter.
Making sense of nickel accumulation and sub-lethal toxic effects in saline waters: Fate and effects of nickel in the green crab, Carcinus maenas.
Blewett, Tamzin A; Glover, Chris N; Fehsenfeld, Sandra; Lawrence, Michael J; Niyogi, Som; Goss, Greg G; Wood, Chris M
In freshwater, invertebrates nickel (Ni) is considered an ionoregulatory toxicant, but its mechanism of toxicity in marine settings, and how this varies with salinity, is poorly understood. This study investigated Ni accumulation and physiological mechanisms of sub-lethal Ni toxicity in the euryhaline green crab Carcinus maenas. Male crabs were exposed to 8.2μg/L (the US EPA chronic criterion concentration for salt waters) of waterborne Ni (radiolabelled with (63)Ni) at three different salinities, 20%, 60% and 100% SW for 24h. Whole body Ni accumulation in 20% SW was 3-5 fold greater than in 60% or 100% SW, and >80% of accumulated Ni was in the carapace at all salinities. Ni also accumulated in posterior gill 8, which showed a higher accumulation in 20% SW than in other salinities, a pattern also seen at higher exposure concentrations of Ni (500 and 3000μg/L). Gill perfusion experiments revealed that Ni was taken up by both anterior and posterior gills, but in 20% SW the posterior gill 8, which performs ionoregulatory functions, accumulated more Ni than the anterior gill 5, which primarily has a respiratory function. The sub-lethal consequences of Ni exposure were investigated by placing crabs in Ni concentrations of 8.2, 500, and 3000μg/L at 20, 60 or 100% SW for 24h. In 20% SW, haemolymph Ca levels were significantly decreased by exposure to Ni concentrations of 8.2μg/L or higher, whereas Na concentrations were depressed only at 3000μg/L. Na(+)/K(+)-ATPase activity was inhibited at both 500 and 3000μg/L in gill 8, but only in 20% SW. Haemolymph K, Mg, and osmolality were unaffected throughout, though all varied with salinity in the expected fashion. These data suggest that Ni impacts ionoregulatory function in the green crab, in a gill- and salinity-dependent manner. PMID:25914092
Distributions, sources, and ecological risks of DDT-related contaminants in water, suspended particulate matter, and sediments from Haihe Plain, Northern China.
Wang, Yan; He, Wei; Qin, Ning; He, Qi-Shuang; Kong, Xiang-Zhen; Tao, Shu; Xu, Fu-Liu
The residual levels of dichlorodiphenyltrichloroethane (DDT) and its metabolites (DDXs, including p,p'-DDT, DDD, and DDE) in water, suspended particulate matter (SPM), and sediments from major rivers, lakes, and reservoirs in Haihe Plain were measured with a gas chromatograph equipped with a (63)Ni microelectron capture detector. In the fall of 2004, the contents of the total DDXs in the water and SPM were 0.29 ± 0.69 ng L(-1) and 423.13 ± 577.85 ng g(-1) dry wt., respectively. In the spring of 2005, the total DDXs were 0.36 ± 0.91 ng L(-1) for water and 35.93 ± 62.65 ng g(-1) dry wt. for SPM. The average concentration of DDXs for sediments was 7.10 ± 7.57 ng g(-1) dry wt. during the two seasons. The Eastern-Hebei-Province Coastland River System was the most polluted, which was mainly attributable to the extensive use of DDT pesticide and dicofol in that system. Recent DDT inputs still occur in some regions, as indicated by DDT/(DDD + DDE) > 1 at 29-36 % of the sites for water and 55-61 % of the sites for SPM. The potential ecological risks of DDT in the water were assessed using a species sensitivity distribution model. Only shrimp and crabs were found to have potentially affected fraction values of 1.63 × 10(-3) to 2.27 × 10(-4), with probabilities beyond the hazardous concentration for 5 % of species (HC5) values of 1.90-2.56 %, suggesting only slight risks. DDXs in the sediments of some sites were also of potential risk to benthic organism based on consensus-based sediment quality guidelines. PMID:22580748
Proteus mirabilis urease: histidine 320 of UreC is essential for urea hydrolysis and nickel ion binding within the native enzyme.
Sriwanthana, B; Mobley, H L
Proteus mirabilis urease, a nickel-containing enzyme, has been established as a critical virulence determinant in urinary tract infection. An amino acid sequence (residues 308 to 327: TVDEHLDMLMVCHHLDPSIP) within the large urease subunit, UreC, is highly conserved for every urease examined thus far and has been suggested to reside within the enzyme active site. Histidine residues have been postulated to play a role in catalysis by coordinating Ni2+ ions. To test this hypothesis, oligonucleotide-directed mutagenesis was used to change amino acid His-320 to Leu-320 within UreC. The base change (CAT for His-320 to CTT for Leu-320) was confirmed by DNA sequencing. The recombinant and mutant proteins were expressed at similar levels in Escherichia coli as detected by Western blotting (immunoblotting) of denaturing and nondenaturing gels. Specific activities of the enzymes were quantitated after partial purification. Strains expressing the mutant enzyme showed no detectable activity, whereas strains expressing the recombinant enzyme hydrolyzed urea at 149 mumol of NH3 per min per mg of protein. In addition, the mutant enzyme was able to incorporate only about one-half (58%) of the amount of 63Ni2+ incorporated by the active recombinant enzyme. While the mutation of His-320 to Leu-320 within UreC does not affect expression or assembly of urease polypeptide subunits UreA, UreB, and UreC His-320 of UreC is required for urea hydrolysis and proper incorporation of Ni2+ into apoenzyme. PMID:8500894
s-process nucleosynthesis in massive stars: new results on 60Fe, 62Ni and 64Ni
NASA Astrophysics Data System (ADS)
Domingo-Pardo, C.; Dillmann, I.; Faestermann, T.; Giesen, U.; Görres, J.; Heil, M.; Horn, S.; Käppeler, F.; Köchli, S.; Korschinek, G.; Lachner, J.; Maiti, M.; Marganiec, J.; Neuhausen, J.; Nolte, R.; Poutivtsev, M.; Reifarth, R.; Rugel, R.; Schumann, D.; Uberseder, E.; Voss, F.; Walter, S.; Wiescher, M.
The s process synthesizes the elements between Fe and Sr in massive stars during two major evolutionary stages, convective core He burning and C shell burning. This scenario implies fascinating consequences for the chemical evolution of the star. For instance, the neutron capture rate at each isotope can have a big influence on the production of many of the subsequent higher mass isotopes. Correspondingly, one needs to know the (n,γ) cross sections of the involved isotopes with high accuracy in order to determine the abundance pattern reliably and to obtain a consistent picture of this stage. This contribution gives an overview on recent and future experiments for the Fe/Ni nucleosynthesis in massive stars. New results on 60Fe, 62Ni and 64Ni are reported. 60Fe is mostly produced during the short convective C shell burning phase, where peak densities of ~1011 cm-3 are reached, prior to the SN explosion. The stellar (n,γ) cross section of 60Fe could be measured with a 1 μg sample obtained at PSI (Switzerland), which was sufficient for an activation measurement using the intense, quasi-stellar neutron field for a thermal energy of 25 keV at the Karlsruhe Van de Graaff accelerator. The FZK accelerator was also used for an activation of 62Ni, whereas in this case, the number of 63Ni nuclei produced were determined via accelerator mass spectroscopy at the Maier-Leibnitz-Laboratorium in Garching/Munich. The (n,γ) cross section of 64Ni at a stellar temperature equivalent to 50 keV has been measured in a collaboration between FZK Karlsruhe and PTB Braunschweig. Finally, complementary time of flight measurements on the Fe and Ni isotopes over a broad energy range are planned at the white neutron source n_TOF of CERN for the future campaign in 2009.
DS02 fluence spectra for neutrons and gamma rays at Hiroshima and Nagasaki with fluence-to-kerma coefficients and transmission factors for sample measurements.
Egbert, Stephen D; Kerr, George D; Cullings, Harry M
Fluence spectra at several ground distances in Hiroshima and Nagasaki are provided along with associated fluence-to-kerma coefficients from the Dosimetry System 2002 (DS02). Also included are transmission factors for calculating expected responses of in situ sample measurements of neutron activation products such as (32)P,(36)Cl,(39)Ar,(41)Ca, (60)Co,(63)Ni,(152)Eu, and (154)Eu. The free-in-air (FIA) fluences calculated in 2002 are available for 240 angles, 69 energy groups, 101 ground distances, 5 heights, 4 radiation source components, 2 cities. The DS02 code uses these fluences partitioned to a prompt and delayed portion, collapsed to 58 energy groups and restricted to 97 ground distances. This is because the fluence spectra were required to be in the same format that was used in the older Dosimetry System 1986 (DS86) computer code, of which the DS02 computer code is a modification. The 2002 calculation fluences and the collapsed DS02 code fluences are presented and briefly discussed. A report on DS02, which is available on the website at the Radiation Effects Research Foundation, provides tables and figures of the A-bomb neutron and gamma-ray output used as the sources in the 2002 radiation transport calculations. While figures illustrating the fluence spectra at several ground ranges are presented in the DS02 Report, it does not include any tables of the calculated fluence spectra in the DS02 report. This paper provides, at several standard distances from the hypocenter, the numerical information which is required to translate the FIA neutron fluences given in DS02 to a neutron activation measurement or neutron and gamma-ray soft-tissue dose. PMID:17643260
Nitrile glove permeation of benomyl.
Zainal, H; Hee, S S Que
The aim of this study was to investigate permeation of the fungicide benomyl at its highest field application concentration (0.70 mg/mL) in Benlate 50 WP aqueous solution (1.4 mg/mL) through two types of unsupported and unlined nitrile gloves--a disposable latex glove (Safeskin) and an industrial chemical-resistant glove (Solvex)--using an American Society for Testing and Materials (ATSM)-type permeation cell with isopropanol collection medium. The permeation cell was contained in a moving-tray water bath at 30.0 degrees C +/- 0.5 degrees C. The collection medium was evaporated and the residue derivatized with an optimized method (2,3,4,5,6-pentafluoro)benzyl bromide to form the disubstituted derivative of carbendazim (CARB), CARB.2PFB. The latter in isooctane was then quantified by gas chromatography- 63Ni-electron capture detection (GC-ECD) by the internal standard method. GC-ECD, GC-mass spectrometry (GC-MS), and reflectance infrared investigations showed that little degradation of benomyl occurred in the challenge solution of aqueous Benlate during an 8-hour exposure period. Benomyl was collected as a mixture of CARB and benomyl as shown by the presence of a diagnostic chromatographic peak identified by GC-MS. The amounts permeated during the same time period were always higher for Safeskin than for Solvex gloves, with the latter being approximately 18 times more protective than the former after 8 hours of continuous exposure. Although the Solvex gloves were safe to wear at least for 4 hours and for almost 8 hours, the ASTM breakthrough threshold was used as reference and thus ignored carcinogenic effects. Reflectance infrared investigations detected benomyl and CARB on the glove challenge surface after drying and confirmed that the cleaned glove surfaces after permeation experiments did not differ in infrared reflectance spectra from the corresponding surfaces just before the permeation experiments. PMID:16446997
Late Archean mafic volcanism in the Rainy Lake area, Minnesota
Day, W.C.
The Late Archean greenstone-granite terrane of the Rainy Lake area of Minnesota contains a bimodal suite of mafic and felsic volcanic and coeval intrusive rocks. New geochemical data show that the mafic rocks occur in three distinct suites: (1) low-Ti olivine- and quartz-tholeiite, (2) high-Ti quartz-tholeiite and basaltic andesite, and (3) calc-alkaline lamprophyric monzodiorite and quartz diorite. The low-Ti tholeiites have only slightly evolved Mg-numbers from 53-63, Ni=125-300 ppm, and MORB-like REE. In contrast, the high-Ti tholeiites are more evolved, with Mg*=26-48, Ni=43-135 ppm, and higher total REE. Compared to the tholeiitic suites, the monzodiorite suite has more primitive Mg-numbers, with Mg*=70-78, Ni<410 ppm, and anomalously high LREE. The two tholeiitic suites cannot be genetically related by simple fractionation from a single parent magma; however, lower degrees of partial melting (<8 percent) of a mantle source (spinel periodotite) with REE=2-4 times chondrites could have produced the high-Ti tholeiites, and higher degrees of melting (20-30 percent) of a similar source could have generated the low-Ti tholeiites. In contrast, the monzodiorite suite must have been generated from either a LREE-rich or (and) a garnet-bearing source (garnet periodotite). The authors conclude that shallow melting (<40-50 km) within the Archean mantle in the Rainy Lake area produced the tholeiitic rocks, and that deep melting (>40-50 km) generated the lamprophyric monzodiorites.
Preclinical Pharmacokinetics, Pharmacodynamics and Safety of Sucroferric Oxyhydroxide
Cozzolino, Mario; Funk, Felix; Rakov, Viatcheslav; Phan, Olivier; Teitelbaum, Isaac
Sucroferric oxyhydroxide (VELPHORO®) is a polynuclear iron-based phosphate binder recently approved for the treatment of hyperphosphataemia in patients with chronic kidney disease (CKD). As a number of the available phosphate binders do not provide the optimal combination of good efficacy, adequate tolerability and low pill burden, sucroferric oxyhydroxide constitutes a promising alternative. Among the attributes of an ideal phosphate binder is minimal absorption and, hence, low risk of systemic toxicity. Accordingly, the iron-releasing properties and absorption, distribution, metabolism and excretion (ADME) profile of sucroferric oxyhydroxide, as well as the possibility of iron accumulation and toxicity, were investigated in a series of preclinical studies. The effect of sucroferric oxyhydroxide on the progression of vascular calcification was also investigated. Sucroferric oxyhydroxide exhibited a high phosphate-binding capacity and low iron-releasing properties across the physiological pH range found in the gastrointestinal tract. In the ADME studies, uptake of 59Fe-radiolabelled sucroferric oxyhydroxide was low in rats and dogs (<1% from a 50 mg Fe/kg bodyweight dose), with the majority of absorbed iron located in red blood cells. Long-term (up to 2 years) administration of sucroferric oxyhydroxide in rats and dogs was associated with modest increases in tissue iron levels and no iron toxicity. Moreoever, in uraemic rats, sucroferric oxyhydroxide was associated with reduced progression of vascular calcification compared with calcium carbonate. In conclusion, sucroferric oxyhydroxide offers a new option for the treatment of hyperphosphataemia, with a high phosphate-binding capacity, minimal iron release, and low potential for iron accumulation and toxicity. PMID:25658128
Silencing the Menkes Copper-Transporting ATPase (Atp7a) Gene in Rat Intestinal Epithelial (IEC-6) Cells Increases Iron Flux via Transcriptional Induction of Ferroportin 1 (Fpn1)123
Gulec, Sukru; Collins, James F.
The Menkes copper-transporting ATPase (Atp7a) gene is induced in rat duodenum during iron deficiency, consistent with copper accumulation in the intestinal mucosa and liver. To test the hypothesis that ATP7A influences intestinal iron metabolism, the Atp7a gene was silenced in rat intestinal epithelial (IEC-6) cells using short hairpin RNA (shRNA) technology. Perturbations in intracellular copper homeostasis were noted in knockdown cells, consistent with the dual roles of ATP7A in pumping copper into the trans-Golgi (for cuproenzyme synthesis) and exporting copper from cells. Intracellular iron concentrations were unaffected by Atp7a knockdown. Unexpectedly, however, vectorial iron (59Fe) transport increased (∼33%) in knockdown cells grown in bicameral inserts and increased further (∼70%) by iron deprivation (compared with negative control shRNA-transfected cells). Additional experiments were designed to elucidate the molecular mechanism of increased transepithelial iron flux. Enhanced iron uptake by knockdown cells was associated with increased expression of a ferrireductase (duodenal cytochrome b) and activity of a cell-surface ferrireductase. Increased iron efflux from knockdown cells was likely mediated via transcriptional activation of the ferroportin 1 gene (by an unknown mechanism). Moreover, Atp7a knockdown significantly attenuated expression of an iron oxidase [hephaestin (HEPH); by ∼80%] and membrane ferroxidase activity (by ∼50%). Cytosolic ferroxidase activity, however, was retained in knockdown cells (75% of control cells), perhaps compensating for diminished HEPH activity. This investigation has thus documented alterations in iron homeostasis associated with Atp7a knockdown in enterocyte-like cells. Alterations in copper transport, trafficking, or distribution may underlie the increase in transepithelial iron flux noted when ATP7A activity is diminished. PMID:24174620
The iron chelator, deferasirox, as a novel strategy for cancer treatment: oral activity against human lung tumor xenografts and molecular mechanism of action.
Lui, Goldie Y L; Obeidy, Peyman; Ford, Samuel J; Tselepis, Chris; Sharp, Danae M; Jansson, Patric J; Kalinowski, Danuta S; Kovacevic, Zaklina; Lovejoy, David B; Richardson, Des R
Deferasirox is an orally effective iron (Fe) chelator currently used for the treatment of iron-overload disease and has been implemented as an alternative to the gold standard chelator, desferrioxamine (DFO). Earlier studies demonstrated that DFO exhibits anticancer activity due to its ability to deplete cancer cells of iron. In this investigation, we examined the in vitro and in vivo activity of deferasirox against cells from human solid tumors. To date, there have been no studies to investigate the effect of deferasirox on these types of tumors in vivo. Deferasirox demonstrated similar activity at inhibiting proliferation of DMS-53 lung carcinoma and SK-N-MC neuroepithelioma cell lines compared with DFO. Furthermore, deferasirox was generally similar or slightly more effective than DFO at mobilizing cellular (59)Fe and inhibiting iron uptake from human transferrin depending on the cell type. However, deferasirox potently inhibited DMS-53 xenograft growth in nude mice when given by oral gavage, with no marked alterations in normal tissue histology. To understand the antitumor activity of deferasirox, we investigated its effect on the expression of molecules that play key roles in metastasis, cell cycle control, and apoptosis. We demonstrated that deferasirox increased expression of the metastasis suppressor protein N-myc downstream-regulated gene 1 and upregulated the cyclin-dependent kinase inhibitor p21(CIP1/WAF1) while decreasing cyclin D1 levels. Moreover, this agent increased the expression of apoptosis markers, including cleaved caspase-3 and cleaved poly(ADP-ribose) polymerase 1. Collectively, we demonstrate that deferasirox is an orally effective antitumor agent against solid tumors. PMID:23074173
Iron acquisition by phytosiderophores contributes to cadmium tolerance.
Meda, Anderson R; Scheuermann, Enrico B; Prechsl, Ulrich E; Erenoglu, Bülent; Schaaf, Gabriel; Hayen, Heiko; Weber, Günther; von Wirén, Nicolaus
Based on the ability of phytosiderophores to chelate other heavy metals besides iron (Fe), phytosiderophores were suggested to prevent graminaceous plants from cadmium (Cd) toxicity. To assess interactions between Cd and phytosiderophore-mediated Fe acquisition, maize (Zea mays) plants were grown hydroponically under limiting Fe supply. Exposure to Cd decreased uptake rates of 59Fe(III)-phytosiderophores and enhanced the expression of the Fe-phytosiderophore transporter gene ZmYS1 in roots as well as the release of the phytosiderophore 2'-deoxymugineic acid (DMA) from roots under Fe deficiency. However, DMA hardly mobilized Cd from soil or from a Cd-loaded resin in comparison to the synthetic chelators diaminetriaminepentaacetic acid and HEDTA. While nano-electrospray-high resolution mass spectrometry revealed the formation of an intact Cd(II)-DMA complex in aqueous solutions, competition studies with Fe(III) and zinc(II) showed that the formed Cd(II)-DMA complex was weak. Unlike HEDTA, DMA did not protect yeast (Saccharomyces cerevisiae) cells from Cd toxicity but improved yeast growth in the presence of Cd when yeast cells expressed ZmYS1. When supplied with Fe-DMA as a Fe source, transgenic Arabidopsis (Arabidopsis thaliana) plants expressing a cauliflower mosaic virus 35S-ZmYS1 gene construct showed less growth depression than wild-type plants in response to Cd. These results indicate that inhibition of ZmYS1-mediated Fe-DMA transport by Cd is not related to Cd-DMA complex formation and that Cd-induced phytosiderophore release cannot protect maize plants from Cd toxicity. Instead, phytosiderophore-mediated Fe acquisition can improve Fe uptake in the presence of Cd and thereby provides an advantage under Cd stress relative to Fe acquisition via ferrous Fe. PMID:17337530
Utilization of flotation wastes of copper slag as raw material in cement production.
Alp, I; Deveci, H; Süngün, H
Copper slag wastes, even if treated via processes such as flotation for metal recovery, still contain heavy metals with hazardous properties posing environmental risks for disposal. This study reports the potential use of flotation waste of a copper slag (FWCS) as iron source in the production of Portland cement clinker. The FWCS appears a suitable raw material as iron source containing >59% Fe(2)O(3) mainly in the form of fayalite (Fe(2)SiO(4)) and magnetite (Fe(3)O(4)). The clinker products obtained using the FWCS from the industrial scale trial operations over a 4-month period were characterised for the conformity of its chemical composition and the physico-mechanical performance of the resultant cement products was evaluated. The data collected for the clinker products produced using an iron ore, which is currently used as the cement raw material were also included for comparison. The results have shown that the chemical compositions of all the clinker products including those of FWCS are typical of a Portland cement clinker. The mechanical performance of the standard mortars prepared from the FWCS clinkers were found to be similar to those from the iron ore clinkers with the desired specifications for the industrial cements e.g. CEM I type cements. Furthermore, the leachability tests (TCLP and SPLP) have revealed that the mortar samples obtained from the FWCS clinkers present no environmental problems while the FWCS could act as the potential source of heavy metal contamination. These findings suggest that flotation wastes of copper slag (FWCS) can be readily utilised as cement raw material due to its availability in large quantities at low cost with the further significant benefits for waste management/environmental practices of the FWCS and the reduced production and processing costs for cement raw materials. PMID:18384950
Competitive effect of iron(III) on metal complexation by humic substances: characterisation of ageing processes.
Lippold, H; Evans, N D M; Warwick, P; Kupsch, H
Aiming at an assessment of counteractive effects on colloid-borne migration of actinides in the event of release from an underground repository, competition by Fe(III) in respect of metal complexation by dissolved organic matter was investigated for the example of Eu(III) as an analogue of trivalent actinides. Complexation with different humic materials was examined in cation exchange experiments, using (59)Fe and (152)Eu as radioactive tracers for measurements in dilute systems as encountered in nature. Competitive effects proved to be significant when Fe is present at micromolar concentrations. Flocculation as a limiting process was attributed to charge compensation of humic colloids. Fe fractions bound to humic acids (HA) were higher than 90%, exceeding the capacity of binding sites at high Fe concentrations. It is thus concluded that the polynuclear structure of hydrolysed Fe(III) is maintained when bound to HA, which is also inferred from UV-Vis spectrometry. The competitive effect was found to be enhanced if Fe and HA were in contact before Eu was added. Depending on the time of Fe/HA pre-equilibration, Eu complexation decreased asymptotically over a time period of several weeks, the amount of bound Fe being unchanged. Time-dependent observations of UV-Vis spectra and pH values revealed that the ageing effect was due to a decline in Fe hydrolysis rather than structural changes within HA molecules. Fe polycations are slowly degraded in contact with humic colloids, and more binding sites are occupied as a consequence of dispersion. The extent of degradation as derived from pH shifts depended on the Fe/HA ratio. PMID:17140629
Electron capture strength on odd- A nucleus 59Co in explosive astrophysical environment
NASA Astrophysics Data System (ADS)
Rahman, Muneeb-Ur; Nabi, Jameel-Un
The Gamow-Teller (GT) transitions within massive stars play sumptuous role in the dynamics of core collapse supernovae. GT strength distributions and electron capture rates have been calculated for odd- A nucleus 59Co within the proton-neutron quasiparticles random phase approximation (pn-QRPA) formalism. The pn-QRPA results are compared with other model calculations and ( n, p) reaction experiment carried out at TRIUMF charge-exchange facility. The pn-QRPA calculated a total B( GT +) strength of 3.3 for 59Co to be compared with the shell model value of 2.5 and the 1.9±0.1 in the ( n, p) charge-exchange reaction. Aufderheide et al. (1993) extracted total strength equaling 2.4±0.3. The placement of GT centroid at 5.6 MeV by the pn-QRPA model is in reasonable agreement with the shell model centroid at 5.1 MeV whereas the measured GT centroid was placed at 4.4±0.3 MeV in the ( n, p) experiment. Fuller, Fowler and Newman (FFN) (1980, 1982a, 1982b), placed the GT centroid at too low excitation energy of 2.0 MeV in the daughter nucleus 59Fe, and this misplacement led to the enhancement of FFN rates. The suppressed pn-QRPA and shell model electron capture rates are in good agreement with each other. The rates are suggestive of higher value of Y e (electron-to-baryon ratio) and may contribute to a more massive homologously collapsing core resulting in a more energetic shock. It might be interesting for the simulators to check the effect of these suppressed rates on the fine-tuning of the time rate of Y e , the concomitant heavy element nucleosynthesis, and, on the energetics of the subsequent shock wave.
The Bradyrhizobium japonicum Ferrous Iron Transporter FeoAB Is Required for Ferric Iron Utilization in Free Living Aerobic Cells and for Symbiosis.
Sankari, Siva; O'Brian, Mark R
The bacterium Bradyrhizobium japonicum USDA110 does not synthesize siderophores for iron utilization in aerobic environments, and the mechanism of iron uptake within symbiotic soybean root nodules is unknown. An mbfA bfr double mutant defective in iron export and storage activities cannot grow aerobically in very high iron medium. Here, we found that this phenotype was suppressed by loss of function mutations in the feoAB operon encoding ferrous (Fe(2+)) iron uptake proteins. Expression of the feoAB operon genes was elevated under iron limitation, but mutants defective in either gene were unable to grow aerobically over a wide external ferric (Fe(3+)) iron (FeCl3) concentration range. Thus, FeoAB accommodates iron acquisition under iron limited and iron replete conditions. Incorporation of radiolabel from either (55)Fe(2+) or (59)Fe(3+) into cells was severely defective in the feoA and feoB strains, suggesting Fe(3+) reduction to Fe(2+) prior to traversal across the cytoplasmic membrane by FeoAB. The feoA or feoB deletion strains elicited small, ineffective nodules on soybean roots, containing few bacteria and lacking nitrogen fixation activity. A feoA(E40K) mutant contained partial iron uptake activity in culture that supported normal growth and established an effective symbiosis. The feoA(E40K) strain had partial iron uptake activity in situ within nodules and in isolated cells, indicating that FeoAB is the iron transporter in symbiosis. We conclude that FeoAB supports iron acquisition under limited conditions of soil and in the iron-rich environment of a symbiotic nodule. PMID:27288412
Prion protein functions as a ferrireductase partner for ZIP14 and DMT1.
Tripathi, Ajai K; Haldar, Swati; Qian, Juan; Beserra, Amber; Suda, Srinivas; Singh, Ajay; Hopfer, Ulrich; Chen, Shu G; Garrick, Michael D; Turner, Jerrold R; Knutson, Mitchell D; Singh, Neena
Excess circulating iron is stored in the liver, and requires reduction of non-Tf-bound iron (NTBI) and transferrin (Tf) iron at the plasma membrane and endosomes, respectively, by ferrireductase (FR) proteins for transport across biological membranes through divalent metal transporters. Here, we report that prion protein (PrP(C)), a ubiquitously expressed glycoprotein most abundant on neuronal cells, functions as a FR partner for divalent-metal transporter-1 (DMT1) and ZIP14. Thus, absence of PrP(C) in PrP-knock-out (PrP(-/-)) mice resulted in markedly reduced liver iron stores, a deficiency that was not corrected by chronic or acute administration of iron by the oral or intraperitoneal routes. Likewise, preferential radiolabeling of circulating NTBI with (59)Fe revealed significantly reduced uptake and storage of NTBI by the liver of PrP(-/-) mice relative to matched PrP(+/+) controls. However, uptake, storage, and utilization of ferritin-bound iron that does not require reduction for uptake were increased in PrP(-/-) mice, indicating a compensatory response to the iron deficiency. Expression of exogenous PrP(C) in HepG2 cells increased uptake and storage of ferric iron (Fe(3+)), not ferrous iron (Fe(2+)), from the medium, supporting the function of PrP(C) as a plasma membrane FR. Coexpression of PrP(C) with ZIP14 and DMT1 in HepG2 cells increased uptake of Fe(3+) significantly, and surprisingly, increased the ratio of N-terminally truncated PrP(C) forms lacking the FR domain relative to full-length PrP(C). Together, these observations indicate that PrP(C) promotes, and possibly regulates, the uptake of NTBI through DMT1 and Zip14 via its FR activity. Implications of these observations for neuronal iron homeostasis under physiological and pathological conditions are discussed. PMID:25862412
Transient overexpression of human H- and L-ferritin chains in COS cells.
Corsi, B; Perrone, F; Bourgeois, M; Beaumont, C; Panzeri, M C; Cozzi, A; Sangregorio, R; Santambrogio, P; Albertini, A; Arosio, P; Levi, S
The understanding of the in vitro mechanisms of ferritin iron incorporation has greatly increased in recent years with the studies of recombinant and mutant ferritins. However, little is known about how this protein functions in vivo, mainly because of the lack of cellular models in which ferritin expression can be modulated independently from iron. To this aim, primate fibroblastoid COS-7 cells were transiently transfected with cDNAs for human ferritin H- and L-chains under simian virus 40 promoter and analysed within 66 h. Ferritin accumulation reached levels 300-500-fold higher than background, with about 40% of the cells being transfected. Thus ferritin concentration in individual cells was increased up to 1000-fold over controls with no evident signs of toxicity. The exogenous ferritin subunits were correctly assembled into homopolymers, but did not affect either the size or the subunit composition of the endogenous heteropolymeric fraction of ferritin, which remained essentially unchanged in the transfected and non-transfected cells. After 18 h of incubation with [59Fe]ferric-nitrilotriacetate, cellular iron incorporation was similar in the transfected and non-transfected cells and most of the protein-bound radioactivity was associated with ferritin heteropolymers, while H- and L-homopolymers remained iron-free. Cell co-transfection with cDNAs for H- and L-chains produced ferritin heteropolymers that also did not increase cellular iron incorporation. It is concluded that transient transfection of COS cells induces a high level of expression of ferritin subunits that do not co-assemble with the endogenous ferritins and have no evident activity in iron incorporation/metabolism. PMID:9461525
Sphagnum-dominated bog systems are highly effective yet variable sources of bio-available iron to marine waters.
Krachler, Regina; Krachler, Rudolf F; Wallner, Gabriele; Steier, Peter; El Abiead, Yasin; Wiesinger, Hubert; Jirsa, Franz; Keppler, Bernhard K
Iron is a micronutrient of particular interest as low levels of iron limit primary production of phytoplankton and carbon fluxes in extended regions of the world's oceans. Sphagnum-peatland runoff is extraordinarily rich in dissolved humic-bound iron. Given that several of the world's largest wetlands are Sphagnum-dominated peatlands, this ecosystem type may serve as one of the major sources of iron to the ocean. Here, we studied five near-coastal creeks in North Scotland using freshwater/seawater mixing experiments of natural creek water and synthetic seawater based on a (59)Fe radiotracer technique combined with isotopic characterization of dissolved organic carbon by Accelerator Mass Spectrometry. Three of the creeks meander through healthy Sphagnum-dominated peat bogs and the two others through modified peatlands which have been subject to artificial drainage for centuries. The results revealed that, at the time of sampling (August 16-24, 2014), the creeks that run through modified peatlands delivered 11-15μg iron per liter creek water to seawater, whereas the creeks that run through intact peatlands delivered 350-470μg iron per liter creek water to seawater. To find out whether this humic-bound iron is bio-available to marine algae, we performed algal growth tests using the unicellular flagellated marine prymnesiophyte Diacronema lutheri and the unicellular marine green alga Chlorella salina, respectively. In both cases, the riverine humic material provided a highly bio-available source of iron to the marine algae. These results add a new item to the list of ecosystem services of Sphagnum-peatlands. PMID:26971209
Iron Acquisition by Phytosiderophores Contributes to Cadmium Tolerance1[OA
Meda, Anderson R.; Scheuermann, Enrico B.; Prechsl, Ulrich E.; Erenoglu, Bülent; Schaaf, Gabriel; Hayen, Heiko; Weber, Günther; von Wirén, Nicolaus
Based on the ability of phytosiderophores to chelate other heavy metals besides iron (Fe), phytosiderophores were suggested to prevent graminaceous plants from cadmium (Cd) toxicity. To assess interactions between Cd and phytosiderophore-mediated Fe acquisition, maize (Zea mays) plants were grown hydroponically under limiting Fe supply. Exposure to Cd decreased uptake rates of 59Fe(III)-phytosiderophores and enhanced the expression of the Fe-phytosiderophore transporter gene ZmYS1 in roots as well as the release of the phytosiderophore 2′-deoxymugineic acid (DMA) from roots under Fe deficiency. However, DMA hardly mobilized Cd from soil or from a Cd-loaded resin in comparison to the synthetic chelators diaminetriaminepentaacetic acid and HEDTA. While nano-electrospray-high resolution mass spectrometry revealed the formation of an intact Cd(II)-DMA complex in aqueous solutions, competition studies with Fe(III) and zinc(II) showed that the formed Cd(II)-DMA complex was weak. Unlike HEDTA, DMA did not protect yeast (Saccharomyces cerevisiae) cells from Cd toxicity but improved yeast growth in the presence of Cd when yeast cells expressed ZmYS1. When supplied with Fe-DMA as a Fe source, transgenic Arabidopsis (Arabidopsis thaliana) plants expressing a cauliflower mosaic virus 35S-ZmYS1 gene construct showed less growth depression than wild-type plants in response to Cd. These results indicate that inhibition of ZmYS1-mediated Fe-DMA transport by Cd is not related to Cd-DMA complex formation and that Cd-induced phytosiderophore release cannot protect maize plants from Cd toxicity. Instead, phytosiderophore-mediated Fe acquisition can improve Fe uptake in the presence of Cd and thereby provides an advantage under Cd stress relative to Fe acquisition via ferrous Fe. PMID:17337530
Ultrastructural, Cytochemical, and Radioautographic Localization of Placental Iron
Parmley, Richard T.; Barton, James C.; Conrad, Marcel E.
Maternal-fetal iron transfer across the guinea pig hemomonochorial placenta during the first, second, and third trimesters was examined using ultrastructural, cytochemical, radioautographic, and ferrokinetic methods. Acid ferrocyanide stained inorganic ferric iron on and in sinusoidal microvilli, cytoplasmic matrix or ground substance, and the outer basal plasmalemma of epithelial cells. Some stain deposits were observed within and on either side of the basement membrane. The extraluminal outer plasmalemma, intercellular junctions, and cytoplasm of endothelial cells frequently contained numerous stain deposits. Staining of trophoblast sinusoidal microvilli was similar during early and late gestation, whereas the staining of the basement membrane and endothelial cells was most prominent during the second and third trimesters. Staining of ferric iron was encountered in rare cytoplasmic granules of epithelial cells during late gestation, but not during early gestation. Placental macrophages contained acid-ferrocyanide-reactive ferric iron in large heterophagosomes and hyaloplasm. Acid ferricyanide failed to localize ferrous iron in either epithelial cells or macrophages. Light-microscopic radioautographic studies localized radioiron in placental epithelial cells and Prussian-blue-positive macrophages in specimens obtained 30 minutes after injection of radioiron (55Fe, 59Fe) into the maternal saphenous vein. At the ultrastructural level labeling was observed (in order of decreasing grain density) in or on the epithelial basal plasmalemma and basement membrane, endothelial cytoplasm, epithelial sinusoidal microvilli, and epithelial cytoplasm. Significant staining or radiolabeling was not observed in mitochondria, trophoblast granules, or nuclei. These results indicate that placental non-heme iron is trivalent and moves from the maternal to the fetal circulation by passing through trophoblast microvilli, cytoplasmic matrix, basal plasmalemma, basement membrane
Prion protein functions as a ferrireductase partner for ZIP14 and DMT1
Qian, Juan; Beserra, Amber; Suda, Srinivas; Singh, Ajay; Hopfer, Ulrich; Chen, Shu G.; Garrick, Michael D.; Turner, Jerrold R.; Knutson, Mitchell D.; Singh, Neena
Excess circulating iron is stored in the liver, and requires reduction of non-Tf-bound-iron (NTBI) and transferrin (Tf)-iron at the plasma membrane and endosomes respectively by ferrireductase (FR) proteins for transport across biological membranes through divalent metal transporters. Here, we report that prion-protein (PrPC), a ubiquitously expressed glycoprotein most abundant on neuronal cells, functions as a FR partner for divalent-metal transporter-1 (DMT1) and ZIP14. Thus, absence of PrPC in PrP-knock-out (PrP−/−) mice resulted in markedly reduced liver iron stores, a deficiency that was not corrected by chronic or acute administration of iron by the oral or intra-peritoneal routes. Likewise, preferential radiolabeling of circulating NTBI with 59Fe revealed significantly reduced uptake and storage of NTBI by the liver of PrP−/− mice relative to matched PrP+/+ controls. However, uptake, storage, and utilization of ferritin-bound iron that does not require reduction for uptake was increased in PrP−/− mice, indicating a compensatory response to the iron-deficiency. Expression of exogenous PrPC in HepG2-cells increased uptake and storage of ferric-iron (Fe3+), not ferrous-iron (Fe2+) from the medium, supporting the function of PrPC as a plasma membrane FR. Co-expression of PrPC with ZIP14 and DMT1 in HepG2 cells increased uptake of Fe3+ significantly, and surprisingly, increased the ratio of N-terminally truncated PrPC forms lacking the FR domain relative to full-length PrPC. Together, these observations indicate that PrPC promotes, and possibly regulates the uptake of NTBI through DMT1 and Zip14 via its FR activity. Implications of these observations for neuronal iron homeostasis under physiological and pathological conditions are discussed. PMID:25862412
Uptake of indium-111-labeled platelets and indium-111 oxine by murine kidneys after total-body irradiation
Ebbe, S.; Taylor, S.; Maurer, H.; Kullgren, B.
Radiation nephropathy is a well-known late manifestation of renal irradiation in human beings and experimental animals. Its pathogenesis is unclear, but vascular injury may play a role. Endothelial cells have been demonstrated to manifest a variety of abnormalities within hours of exposure to radiation. In the present experiments mice were exposed to lethal doses of whole-body radiation, and the distribution of {sup 111}In-labeled platelets was evaluated during the first week after irradiation. The purpose was to determine if early abnormalities of endothelial cells would be manifested by altered sequestration of platelets in kidneys and other organs. It was found that the indium accumulated in the kidneys of irradiated mice to a greater extent than in nonirradiated mice, but the pattern of accumulation differed from that seen after injection of radiolabeled platelets. Renal hyperemia was not demonstrable with {sup 51}Cr-labeled red cells, renal vascular permeability was not detected with {sup 125}I-labeled albumin, and the pattern of renal uptake of plasma proteins labeled albumin, and the pattern of renal uptake of plasma proteins labeled with {sup 59}Fe {sup 111}In did not coincide with that seen from {sup 111}In administered as labeled platelets or oxine. Renal uptake of {sup 111}In-oxine was not associated with alterations in urinary or fecal excretion or an increase in total-body retention of the radioisotope. The findings are consistent with the notion that renal vascular injury at the time of irradiation results in accumulation of platelets or platelet constituents during the first week after total-body irradiation of mice. 29 refs., 5 figs., 3 tabs.
Absorption of iron from ferritin is independent of heme iron and ferrous salts in women and rat intestinal segments.
Theil, Elizabeth C; Chen, Huijun; Miranda, Constanza; Janser, Heinz; Elsenhans, Bernd; Núñez, Marco T; Pizarro, Fernando; Schümann, Klaus
Ferritin iron from food is readily bioavailable to humans and has the potential for treating iron deficiency. Whether ferritin iron absorption is mechanistically different from iron absorption from small iron complexes/salts remains controversial. Here, we studied iron absorption (RBC (59)Fe) from radiolabeled ferritin iron (0.5 mg) in healthy women with or without non-ferritin iron competitors, ferrous sulfate, or hemoglobin. A 9-fold excess of non-ferritin iron competitor had no significant effect on ferritin iron absorption. Larger amounts of iron (50 mg and a 99-fold excess of either competitor) inhibited iron absorption. To measure transport rates of iron that was absorbed inside ferritin, rat intestinal segments ex vivo were perfused with radiolabeled ferritin and compared to perfusion with ferric nitrilotriacetic (Fe-NTA), a well-studied form of chelated iron. Intestinal transport of iron absorbed inside exogenous ferritin was 14.8% of the rate measured for iron absorbed from chelated iron. In the steady state, endogenous enterocyte ferritin contained >90% of the iron absorbed from Fe-NTA or ferritin. We found that ferritin is a slow release source of iron, readily available to humans or animals, based on RBC iron incorporation. Ferritin iron is absorbed by a different mechanism than iron salts/chelates or heme iron. Recognition of a second, nonheme iron absorption process, ferritin endocytosis, emphasizes the need for more mechanistic studies on ferritin iron absorption and highlights the potential of ferritin present in foods such as legumes to contribute to solutions for global iron deficiency. PMID:22259191
Intestinal lactoferrin receptor: presence and specificity during development
Davidson, L.A.; Lonnerdal, B.L.
As the major iron-binding protein in breast milk, lactoferrin (Lf) has been suggested to play a role in Fe absorption from milk. The authors previous work has validated the use of the Rhesus monkey as a model for studying this role of Lf. They have identified a specific Lf receptor on the brush border (BB) of juvenile Rhesus small intestine (s.i.) which may facilitate Fe uptake into the mucosal cell. In this study the authors examined the presence and specificity of the Lf receptor during development. BB membrane vesicles were prepared from fetal (113 d gestation), infant (3 m), and adult (12 y) Rhesus s.i.; Binding assays were performed by incubating BB vesicles with 59-Fe-Lf and filtering through a 0.22 ..mu..m filter. The fetal and infant tissues were found to possess receptors with a high affinity for Lf. This early ontogeny indicates the importance of the receptor to the infant. Adult s.i. contained Lf receptors in all regions. Since the adult has no dietary intake of Lf, the receptor may play a role in Fe homeostasis via biliary Lf excretion or may simply continue to be expressed throughout life. The receptors were examined for their affinity for purified bovine Lf and human transferrin, both of which are similar in structure to Lf. No binding was found for either, demonstrating the specificity of the receptor for Lf. The presence of the Lf receptor in fetal tissue and its specificity for Lf implies it is essential for adequate Fe nutrition of the suckling infant.
Loss of NCB5OR in the cerebellum disturbs iron pathways, potentiates behavioral abnormalities, and exacerbates harmaline-induced tremor in mice.
Stroh, Matthew A; Winter, Michelle K; Swerdlow, Russell H; McCarson, Kenneth E; Zhu, Hao
Iron dyshomeostasis has been implicated in many diseases, including a number of neurological conditions. Cytosolic NADH cytochrome b5 oxidoreductase (NCB5OR) is ubiquitously expressed in animal tissues and is capable of reducing ferric iron in vitro. We previously reported that global gene ablation of NCB5OR resulted in early-onset diabetes and altered iron homeostasis in mice. To further investigate the specific effects of NCB5OR deficiency on neural tissue without contributions from known phenotypes, we generated a conditional knockout (CKO) mouse that lacks NCB5OR only in the cerebellum and midbrain. Assessment of molecular markers in the cerebellum of CKO mice revealed changes in pathways associated with cellular and mitochondrial iron homeostasis. (59)Fe pulse-feeding experiments revealed cerebellum-specific increased or decreased uptake of iron by 7 and 16 weeks of age, respectively. Additionally, we characterized behavioral changes associated with loss of NCB5OR in the cerebellum and midbrain in the context of dietary iron deprivation-evoked generalized iron deficiency. Locomotor activity was reduced and complex motor task execution was altered in CKO mice treated with an iron deficient diet. A sucrose preference test revealed that the reward response was intact in CKO mice, but that iron deficient diet consumption altered sucrose preference in all mice. Detailed gait analysis revealed locomotor changes in CKO mice associated with dysfunctional proprioception and locomotor activation independent of dietary iron deficiency. Finally, we demonstrate that loss of NCB5OR in the cerebellum and midbrain exacerbated harmaline-induced tremor activity. Our findings suggest an essential role for NCB5OR in maintaining both iron homeostasis and the proper functioning of various locomotor pathways in the mouse cerebellum and midbrain. PMID:27188291
Case-control study of prostatic cancer in employees of the United Kingdom Atomic Energy Authority.
Rooney, C; Beral, V; Maconochie, N; Fraser, P; Davies, G
OBJECTIVE--To investigate the relation between risk of prostatic cancer and occupational exposures, especially to radionuclides, in employees of the United Kingdom Atomic Energy Authority. DESIGN--Case-control study of men with prostatic cancer and matched controls. Information about sociodemographic factors and exposures to radionuclides and other substances was abstracted and classified for each subject from United Kingdom Atomic Energy Authority records without knowledge of who had cancer. SUBJECTS--136 men with prostatic cancer diagnosed between 1946 and 1986 and 404 matched controls, all employees of United Kingdom Atomic Energy Authority. MAIN OUTCOME MEASURES--Documented or possible contamination with specific radionuclides. RESULTS--Risk of prostatic cancer was significantly increased in men who were internally contaminated with or who worked in environments potentially contaminated by tritium, chromium-51, iron-59, cobalt-60, or zinc-65. Internal contamination with at least one of the five radionuclides was detected in 14 men with prostatic cancer (10%) and 12 controls (3%) (relative risk 5.32 (95% confidence interval 1.87 to 17.24). Altogether 28 men with prostatic cancer (21%) and 46 controls (11%) worked in environments potentially contaminated by at least one of the five radionuclides (relative risk 2.36 (1.26 to 4.43)); about two thirds worked at heavy water reactors (19 men with prostatic cancer and 32 controls (relative risk 2.13 (1.00 to 4.52)). Relative risk of prostatic cancer increased with increasing duration of work in places potentially contaminated by these radionuclides and with increasing level of probable contamination. Prostatic cancer was not associated with exposure to plutonium, uranium, cadmium, boron, beryllium, or organic or inorganic chemicals. CONCLUSIONS--Risk of prostatic cancer risk was increased in United Kingdom Atomic Energy Authority workers who were occupationally exposed to tritium, 51Cr, 59Fe, 60Co, or 65Zn. Exposure to
Study of iron homeostasis following partial hepatectomy in rats with chronic aluminum intoxication.
Contini, María del Carmen; Ferri, Alejandro; Bernal, Claudio A; Carnovale, Cristina E
Effects of both chronic aluminum (Al) exposure and partial hepatectomy on iron (Fe) homeostasis were studied. Male Wistar rats were intraperitoneally administered either 27 mg Al/kg body weight (as aluminum hydroxide) or the vehicle saline, three times a week for 3 mo. After this time, half of the rats of each group was sham operated (SH) and the other half was partially hepatectomized (PH). Animals of the four experimental groups (vehicle+SH [SH]; Al+SH; vehicle+PH [PH], and Al+PH) were killed 48 h after the surgical procedure. Serum, hepatic, and intestinal Al levels were found to be increased both for Al+SH and Al+PH. The serum Fe concentration and transferrin saturation percentage were significantly diminished in the rats of the Al+PH group, thus showing interaction between Al administration and PH. The 59Fe mucosal-to-serosal transport, studied in the intestinal loop in situ, was not affected by Al or PH. The malregulation of intestinal Fe absorption in Al exposure and/or PH when the serum Fe concentration was diminished could be the result of the increased lipid peroxidation (thiobarbituric acid-reactive substances [TBARS]) observed in this tissue. Mucosal TBARS were increased by Al exposure (+26%) and PH (+37%) and interaction between Al and PH was observed (+44%). These results show that when liver surgery is performed after prolonged Al exposure, it leads to impairment of Fe homeostasis. We underline the importance of the exposure to Al, a potentially toxic element, in the study of risk assessment in patients who must be submitted to major liver resection. PMID:17406072
Effects of dietary factors on iron uptake from ferritin in Caco-2 cells
Kalgaonkar, Swati; Lönnerdal, Bo
Biofortification of staple foods with iron (Fe) in the form of ferritin (Ft) is now possible, both by conventional plant breeding methods and transgenic approaches. Ferritin-iron (Ft-Fe) from plants and animals is absorbed well (25-30%) by human subjects, but little is known about dietary factors affecting its absorption. We used human intestinal Caco-2 cells and compared Fe absorption from animal Ft and FeSO4 to determine the effects of inhibitors and enhancers, such as phytic acid, ascorbic acid, tannic acid, calcium, and heme. When post-confluent cells were co-incubated with 59Fe-labeled (1 μM) FeSO4 and dietary factors, at different molar ratios of dietary factor to Fe (phytic acid:Fe,10:1, ascorbic acid:Fe, 50:1, tannic acid:Fe, 50:1, calcium:Fe,10:1, and hemin:Fe,10:1), all inhibited uptake from FeSO4, except ascorbate, confirming earlier studies. In contrast, these dietary factors had little or no effect on Fe uptake from undigested Ft or ferritin digested in vitro at pH 4, except tannins. However, results after in vitro digestion of Ft at pH 2 were similar to those obtained for FeSO4. These results suggest that Fe uptake occurs from both undigested as well as digested Ft, but possibly via different mechanisms. The Fe-Ft stability shown here could minimize Fe-induced oxidation of Fe-supplemented food products. PMID:17509858
Deferoxamine inhibition of malaria is independent of host iron status
Hershko, C.; Peto, T.E.
The mechanism whereby deferoxamine (DF) inhibits the growth of malaria parasites was studied in rats infected with Plasmodium berghei. Peak parasitemia was 32.6% (day 14) in untreated controls and 0.15% (day 7) in rats receiving 0.33 mg/g in 8 hourly DF injections, subcutaneously. DF inhibition of parasite growth was achieved without any reduction in transferrin saturation or hemoglobin synthesis and with only a partial (56%) depletion of hepatic iron stores. Dietary iron depletion resulted in anemia (hematocrit 25 vs. 46%), microcytosis (MCV 54 vs. 60 fl), and reduced transferrin saturation (17 vs. 96%) without any effect on infection (peak parasitemia 30 vs. 36%). Similarly, parenteral iron loading with ferric citrate over 10 d (75 mg iron/kg) failed to aggravate infection. In a search for evidence of direct interaction between DF and parasitized erythrocytes, gel filtration and ultrafiltration was performed on hemolysates obtained from in vivo /sup 59/Fe-labeled parasitized erythrocytes. This showed that 1.1-1.9% of the intracellular radioiron was located in a chelatable, labile iron pool. Incubation of intact cells with 0-500 microM DF resulted in a proportional increase in intracellular iron chelation, and the chelation of all available labile intracellular iron was completed within 6 h. These observations indicate that the severity of P. berghei infection in rats and its in vivo suppression by DF are independent of host iron status and suggest that DF inhibition of malaria involves intracellular chelation of a labile iron pool in parasitized erythrocytes.
Ferrokinetic study of splenic erythropoiesis: Relationships among clinical diagnosis, myelofibrosis, splenomegaly, and extramedullary erythropoiesis
Beguin, Y.; Fillet, G.; Bury, J.; Fairon, Y. )
Splenic erythropoiesis was demonstrated by surface counting of {sup 59}Fe in 129 of 1,350 ferrokinetic studies performed over a 15 year period. These 129 studies were carried out in 108 patients, including 40 with chronic myelogenous leukemia (CML), 24 with agnogenic myeloid metaplasia (AMM), 18 with polycythemia vera (PV), six with a myelodysplastic syndrome, five with acute leukemia, three with prostate or breast carcinoma, two each with aplastic anemia or Hodgkin's disease, and one each with idiopathic thrombocythemia, multiple myeloma, chronic renal failure, or treated hypopituitarism. Splenomegaly was present in 83% of the studies and hepatomegaly in 72%. Grade II-III myelofibrosis was demonstrated in 62% of the cases. Hepatic erythropoiesis was present in 77% of the studies (only 38% in PV), and marrow erythropoiesis was undetectable in 33%. Total erythropoiesis was about twice normal (range 0.2 to 8 times normal) but was ineffective to varying degrees in 86% of the studies. Relationships between organomegaly, myelofibrosis, and extramedullary erythropoiesis, as well as differences among clinical disorders, are discussed. Differences observed between CML in chronic or blastic phase suggested that the erythroid cell line was involved in the proliferative process. It is concluded that splenic erythropoiesis (1) is encountered in a variety of clinical conditions; (2) is not necessarily associated with splenomegaly or myelofibrosis, even in the myeloproliferative disorders; (3) is part of a predominantly extramedullary (in the liver as well as in the spleen), expanded, and largely inefficient total erythropoiesis; and (4) can be evaluated in a semiquantitative manner by surface counting.
Effects of intrarenal injection of nickel subsulfide in rodents
Hopfer, S.M.; Sunderman, F.W. Jr.; Morse, E.E.; Fredrickson, T.N.
After intrarenal (i.r.) administration of 5 mg of nickel subsulfide (..cap alpha..Ni/sub 3/S/sub 2/) to Fischer rats, blood hematocrit became increased within one week and reached 76 +- 1 percent at eight weeks (p<0.001 versus mean hematocrit of 46 +- 1 percent in control rats). The ..cap alpha..Ni/sub 3/S/sub 2/-induced erythrocytosis was attended by intense stimulation of erythropoiesis, with reticulocytosis, increased /sup 59/Fe-uptake into erythrocytes and erythroid hyperplasia in bone marrow and spleen. The half-life of /sup 51/Cr-labeled erythrocytes from ..cap alpha..Ni/sub 3/S/sub 2/-treated rats was prolonged, consistent with increased proportion of circulating juvenile erythrocytes. Histological examination of rat kidneys after i.r. injection of ..cap alpha..Ni/sub 3/S/sub 2/ showed mile inflammation at one and two weeks. Dense black particles of ..cap alpha..Ni/sub 3/S/sub 2/ were visible in histological sections of rat kidneys for eight weeks. 5'-Nucleotidase activity in rat kidney microsomes was inhibited at one to seven days after i.r. injection of ..cap alpha..Ni/sub 3/S/sub 2/. Erythrocytosis did not occur in rats after (a) i.r. implantation of semi-permeable cellulose tubules containing ..cap alpha..Ni/sub 3/S/sub 2/, (b) repeated i.m. injections of ..cap alpha..Ni/sub 3/S/sub 2/, or (c) intrahepatic injection of ..cap alpha..Ni/sub 3/S/sub 2/ after partial hepatectomy. Erythrocytosis did not occur in male BALB/c mice or ground squirrels after i.r. injection of ..cap alpha..Ni/sub 3/S/sub 2/.
Acute Copper and Ascorbic Acid Supplementation Inhibits Non-heme Iron Absorption in Humans.
Olivares, Manuel; Figueroa, Constanza; Pizarro, Fernando
The objective of the study is to determine the effect of copper (Cu) plus the reducing agent ascorbic acid (AA) on the absorption of non-heme iron (Fe). Experimental study with block design in which each subject was his own control. After signing an informed consent, 14 adult women using an effective method of contraception and negative pregnancy test received 0.5 mg Fe, as ferrous sulfate, alone or with Cu, as copper sulfate, plus ascorbic acid (AA/Cu 2/1 molar ratio) at 4/1; 6/1 and 8/1 Cu/Fe molar ratios as an aqueous solution on days 1, 2, 14, and 15 of the study. Fe absorption was assessed by erythrocyte incorporation of iron radioisotopes (55)Fe and (59)Fe. Geometric mean (range ± SD) absorption of Fe at 4/1 and 6/1 Cu/Fe molar ratios (and AA/Cu 2/1 molar ratio) and Fe alone was 57.4 % (35.7-92.1 %), 64.2 % (45.8-89.9 %), and 38.8 % (20.4-73.8 %), respectively (ANOVA for repeated measures p < 0.001; post hoc test Scheffé, p < 0.05). This is attributable to the enhancing effect of AA on non-heme Fe absorption; however, Fe absorption at Cu/Fe 8/1 molar ratio was 47.3 % (27.7-80.8) (p = NS compared with Fe alone). It was expected that Fe absorption would have been equal or greater than at 4/1 and 6/1 molar ratios. Copper in the presence of ascorbic acid inhibits non-heme Fe absorption at Cu/Fe 8/1 molar ratio. PMID:26715577
Measurement of Fractional Exhaled Nitric Oxide as a Marker of Disease Activity in Inflammatory Bowel Disease
Ikonomi, Erkanda; Rothstein, Robin D.; Ehrlich, Adam C.; Friedenberg, Frank K.
Background and Aims Definitive diagnosis of IBD requires endoscopic and pathologic confirmation. These tools are also used to classify disease activity. Our aim was to determine if the fractional exhaled nitric oxide (FeNO) could be utilized to screen for IBD and assess for disease activity. Methods We matched weighted IBD cases and controls from the 2009–2010 NHANES dataset. All subjects underwent measurement of FeNO using standardized techniques. We assessed for potential confounders for FeNO measurement including age, height, and asthma. For IBD subjects, we used the presence of diarrhea, fatigue, and weight loss as a proxy for IBD activity. Laboratory parameters examined to estimate disease activity included anemia (≤ 10 g/dl), iron deficiency (ferritin ≤ 20 ng/ml), hypoalbuminemia (≤ 3.2 g/dl), and CRP (≥ 1.1 mg/dl). Results The weighted sample represented 199,414,901 subjects. The weighted prevalence of IBD was 2,084,895 (1.0%). IBD subjects had nearly the same FeNO level as those without IBD (17.0 ± 16.2 vs. 16.7 ± 14.5 ppb). The odds of a FeNO > 25 ppb was half (OR=0.501; 95% CI 0.497–0.504) for subjects with IBD compared to those without IBD after controlling for confounders. The AUROC curve for FeNO was 0.47 (0.35–0.59). FeNO levels were not higher in patients with laboratory values suggestive of active disease. FeNO levels were higher in IBD patients with diarrhea, rectal urgency, and fatigue but were lower in those with unintentional weight loss. Conclusion Measurement of FeNO does not appear to be useful to screen for IBD or assess disease activity. PMID:27398403
Electron absorbed fractions of energy and S-values in an adult human skeleton based on µCT images of trabecular bone
NASA Astrophysics Data System (ADS)
Kramer, R.; Richardson, R. B.; Cassola, V. F.; Vieira, J. W.; Khoury, H. J.; Lira, C. A. B. de O.; Robson Brown, K.
When the human body is exposed to ionizing radiation, among the soft tissues at risk are the active marrow (AM) and the bone endosteum (BE) located in tiny, irregular cavities of trabecular bone. Determination of absorbed fractions (AFs) of energy or absorbed dose in the AM and the BE represent one of the major challenges of dosimetry. Recently, at the Department of Nuclear Energy at the Federal University of Pernambuco, a skeletal dosimetry method based on µCT images of trabecular bone introduced into the spongiosa voxels of human phantoms has been developed and applied mainly to external exposure to photons. This study uses the same method to calculate AFs of energy and S-values (absorbed dose per unit activity) for electron-emitting radionuclides known to concentrate in skeletal tissues. The modelling of the skeletal tissue regions follows ICRP110, which defines the BE as a 50 µm thick sub-region of marrow next to the bone surfaces. The paper presents mono-energetic AFs for the AM and the BE for eight different skeletal regions for electron source energies between 1 keV and 10 MeV. The S-values are given for the beta emitters 14C, 59Fe, 131I, 89Sr, 32P and 90Y. Comparisons with results from other investigations showed good agreement provided that differences between methodologies and trabecular bone volume fractions were properly taken into account. Additionally, a comparison was made between specific AFs of energy in the BE calculated for the actual 50 µm endosteum and the previously recommended 10 µm endosteum. The increase in endosteum thickness leads to a decrease of the endosteum absorbed dose by up to 3.7 fold when bone is the source region, while absorbed dose increases by ~20% when the beta emitters are in marrow.
Measurement of radionuclide activities induced in target components of an IBA CYCLONE 18/9 by gamma-ray spectrometry with HPGe and LaBr3: Ce detectors.
Tomarchio, Elio
product disposal work. For a longer time, only long-lived radionuclides (57)Co, (60)Co, and (54)Mn contribute to dose rate. PMID:24949919
Mechanical characteristics and microstructure of weld joint of high-temperature martensitic steel containing 9% Cr
NASA Astrophysics Data System (ADS)
Shakhova, Ya. E.; Belyakov, A. N.; Kaibyshev, R. O.
The structure and mechanical characteristics of a weld joint of 10Kh9K3V2MFBR steel (0.097 C, 0.17.Si, 0.54 Mn, 8.75 Cr, 0.21 Ni, 0.51 Mo, 0.07 Nb, 0.23 V, 0.004 N, 0.003 B, 1.6 W, 0.15 Cu, and Fe for balance, wt %) have been studied; the joint was produced by hand welding in an argon atmosphere using 03Kh20N45M7G6B welding wire (0.3 C, 20 Cr, 45 Ni, 7 Mo, 6 Mn, and 1 Nb, wt %). The weld joint is divided into the zone of the base metal, a thermal effect zone, which consists of zones that contain fine and coarse original austenitic grains, and the zone of seam metal. It has been shown that the weld joint of 10Kh9K3V2MFBR steel possesses high strength characteristics at the room temperature under static loading and a satisfactorily impact toughness, which has the minimum value of 30 J/cm2 in the zone of the seam metal and does not depend on the temperature. With a decrease in the temperature from the room temperature to 253 K, a ductile-brittle transition occurs in the thermal effect zone. Creep tests carried out at the temperature of 923 K have shown that the long-term strength of the weld seam is lower than that of the base material in the entire stress range being tested. At stresses of 140 MPa or higher, the acceleration of creep in the weld seam is observed, while at low stresses of about 120 MPa, the rates of creep in the weld seam and in the base metal remain similar until the transition to the stage of accelerated fracture occurs. The difference in the values of the long-term strength is due to premature fracture, which occurs in the thermal effect zone with the finegrained structure.
a New ENDF/B-VII.0 Based Multigroup Cross-Section Library for Reactor Dosimetry
NASA Astrophysics Data System (ADS)
Alpan, F. A.; Anderson, S. L.
The latest of the ENDF/B libraries, ENDF/B-VII.0 was released in December 2006. In this paper, the ENDF/B-VII.O evaluations were used in generating a new coupled neutron/gamma multigroup library having the same group structure of VITAMIN-B6, i.e., the 199-neutron, 42-gamma group library. The new library was generated utilizing NJOY99.259 for pre-processing and the AMPX modules for post-processing of cross sections. An ENDF/B-VI.3 based VITAMIN-B6-like library was also generated. The fine-group libraries and the ENDF/B-VI.3 based 47-neutron, 20-gamma group BUGLE-96 library were used with the discrete ordinates code DORT to obtain a three-dimensional synthesized flux distribution from r, r-θ, and r-z models for a standard Westinghouse 3-loop design reactor. Reaction rates were calculated for ex-vessel neutron dosimetry containing 63Cu(n,α)60Co, 46Ti(n,p)46Sc, 54Fe(n,P)54Mn, 58Ni(n,P)58Co, 238U(n,f)137Cs, 237Np(n,f)137Cs, and 59Co(n,γ)60Co (bare and cadmium covered) reactions. Results were compared to measurements. In comparing the 199-neutron, 42-gamma group ENDF/B-VI.3 and ENDF/B-VII.O libraries, it was observed that the ENDF/B-VI.3 based library results were in better agreement with measurements. There is a maximum difference of 7% (for the 63Cu(n,α)60Co reaction rate calculation) between ENDF/B-VI.3 and ENDF/B-VII.O. Differences between ENDF/B-VI.3 and ENDF/B-VII.O libraries are due to 16O, 1H, 90Zr, 91Zr, 92Zr, 238U, and 239Pu evaluations. Both ENDF/B-VI.3 and ENDF/B-VII.O library calculated reaction rates are within 20% of measurement and meet the criterion specified in the U. S. Nuclear Regulatory Commission Regulatory Guide 1.190, "Calculational and Dosimetry Methods for Determining Pressure Vessel Neutron Fluence."
Neutron detection and multiplicity counting using a boron-loaded plastic scintillator/bismuth germanate phoswich detector array
Miller, M.C.
Neutron detection and multiplicity counting has been investigated using a boron-loaded plastic scintillator/bismuth germanate phoswich detector array. Boron-loaded plastic combines neutron moderation (H) and detection ({sup 10}B) at the molecular level, thereby physically coupling increasing detection efficiency and decreasing die-away time with detector volume. Both of these characteristics address a fundamental limitation of thermal-neutron multiplicity counters, where {sup 3}He proportional counters are embedded in a polyethylene matrix. Separation of the phoswich response into its plastic scintillator and bismuth germanate components was accomplished on a pulse-by-pulse basis using custom integrator and timing circuits. In addition, a custom time-tag module was used to provide a time for each detector event. Analysis of the combined energy and time event stream was performed by calibrating each detector`s response and filtering based on the presence of a simultaneous energy deposition corresponding to the {sup 10}B(n,alpha) reaction products in the plastic scintillator (93 keV{sub ee}) and the accompanying neutron-capture gamma ray in the bismuth germanate (478 keV). Time-correlation analysis was subsequently performed on the filtered event stream to obtain shift-register-type singles and doubles count rates. Proof-of-principle measurements were conducted with a variety of gamma-ray and neutron sources including {sup 137}Cs, {sup 54}Mn, AmLi, and {sup 252}Cf. Results of this study indicate that a neutron-capture probability of {approximately}10% and a die-away time of {approximately}10 {micro}s are possible with a 4-detector array with a detector volume of 1600 cm{sup 3}. Simulations were performed that indicate neutron-capture probabilities on the order of 50% and die-away times of less than 4 {micro}s are realistically achievable. While further study will be required for practical application of such a detection system, the results obtained in this
Determination of environmental radiation flux and organ doses using in-situ gamma spectroscopy
NASA Astrophysics Data System (ADS)
Al-Ghamdi, Abdulrahman S.
Contamination of buildings represent a unique problem during Decontamination and Decommissioning (D&D) of nuclear facilities. It is necessary to determine the long-lived radionuclides and their respective specific activities in building materials before the right D&D decision can be made. At the same time, radiation risk of workers or potential occupants in the facility must be assessed as part of the D&D process. The goal of this project was to develop a methodology of obtaining gamma radiation flux and organ doses from in-situ gamma spectroscopy. Algorithms were developed to simulate the response functions of the HPGe detector and to convert the spectra into photon fluences. A Monte Carlo code, MCNP4C, was used to simulate HPGe detector response and to develop the conversion algorithm. The simulated spectra obtained for an HPGe detector were converted to flux using the algorithm for various different geometries. The response functions of the detector are presented in this document for the gamma energies from 60 keV to 2.2 MeV. Published fluence-to-dose conversion coefficients were used to calculate organ doses and effective dose equivalent. We then tested the theory at a 100-MeV linear electron accelerator at Rensselaer Polytechnic Institute (RPI). Samples of the activated concrete walls and floor in the target room of the Linac facility as well as some steel samples were taken to quantify the specific activities of the structures. The results show that the most important long-lived radionuclides include 22 Na, 46Sc, 54 Mn, 57Co, 60 Co, 65Zn, 152 Eu and 154Eu, depending on the location and composition of the material. The specific activities at the Linac facility range from 1.15E-01 to 765.31 muCi/Kg. The annual effective dose equivalent was assessed to be 2.44 mSv y-1 (0.244 rem y-1 ), which is about 5% of the Annual EDE limits to workers.
Characteristics of inositol trisphosphate mediated Ca/sup 2 +/ release from permeabilized hepatocytes
Joseph, S.K.; Williamson, J.R.
Ca/sup 2 +/ release triggered by inositol trisphosphate (IP/sub 3/) has been measured in saponin-permeabilized hepatocytes with /sup 45/Ca/sup 2 +/ or Quin 2. The initial rate of Ca/sup 2 +/ release was not markedly affected by the incubation temperature (175 +/- 40 pmol/s/mg at 30/sup 0/C versus 133 +/- 24 pmol/s/mg at 4/sup 0/C). This result is consistent with the membrane translocation of Ca/sup 2 +/ occurring through an ion-channel rather than an ion-carrier. The amount of Ca/sup 2 +/ released by IP/sub 3/ was not affected by pH (6.5-8.0) or by compounds that inhibit voltage-gated Ca/sup 2 +/ channels. La/sup 3 +/ (100 ..mu..M) markedly inhibits the effect of 1 ..mu..M IP/sub 3/. The possibility that La/sup 3 +/ chelates IP/sub 3/ cannot be excluded since the effect of La/sup 3 +/ can be overcome by increasing the IP/sub 3/ concentration. IP/sub 3/-mediated Ca/sup 2 +/ release displays a requirement for a permeant cation in the incubation medium. Optimal release is observed with K/sup +/ gluconate. Other monovalent cations, with the exception of Li/sup +/, can substitute for K/sup +/. Permeant anions, at concentrations above 40 mM, inhibit Ca/sup 2 +/ release produced by IP/sub 3/. Cl/sup -/, Br/sup -/, I/sup -/, and SO/sub 4//sup 2 -/ were equally effective. Ca/sup 2 +/ release was not inhibited by DIDS or Furosemide. /sup 85/Sr/sup 2 +/ and /sup 54/Mn/sup 2 +/ fluxes were also stimulated by IP/sub 3/. These results suggest that IP/sub 3/ acts to gate a divalent cation channel. The translocation of positive charge through this channel is balanced by ancillary movements of monovalent cations and anions across the reticular membrane.
Characteristics of inositol trisphosphate-mediated Ca/sup 2 +/ release from permeabilized hepatocytes
Joseph, S.K.; Williamson, J.R.
Ca/sup 2 +/ release triggered by inositol trisphosphate (Ins(1,4,5)P/sub 3/) has been measured in saponin-permeabilized hepatocytes with /sup 45/Ca/sup 2 +/ or Quin 2. The initial rate of Ca/sup 2 +/ release was not greatly affected by the incubation temperature. The amount of Ca/sup 2 +/ released by Ins(1,4,5)P/sub 3/ was not affected by pH (6.5-8.0). La/sup 3 +/ (100 ..mu..M) markedly inhibited the effect of 1 ..mu..M Ins(1,4,5)P/sub 3/. The possibility that La/sup 3 +/ chelates Ins(1,4,5)P/sub 3/ cannot be excluded since the effect of La/sup 3 +/ could be overcome by increasing the Ins(1,4,5)P/sub 3/ concentration. Ins(1,4,5)P/sub 3/-mediated Ca/sup 2 +/ release showed a requirement for permeant cations in the incubation medium. Optimal release was observed with potassium gluconate. Other monovalent cations, with the exception of Li/sup +/, can substitute for K/sup +/. Permeant anions, at concentrations above 40 mM, inhibited Ca/sup 2 +/ release produced by Ins(1,4,5)P/sub 3/. Cl/sup -/, Br/sup -/, I/sup -/, and SO/sup 2 -//sub 4/ were equally effective as inhibitors. Ins(1,4,5)P/sub 3/ also caused the release of /sup 54/Mn/sup 2 +/ and /sup 85/Sr/sup 2 +/ accumulated by the permeabilized hepatocytes. The results are consistent with Ins(1,4,5)P/sub 3/ promoting the membrane translocation of divalent cations through an ion channel rather than an ion carrier. The translocation of positive charge through this channel is balanced by ancillary movements of monovalent cations and anions across the reticular membranes. The transport systems responsible for these compensatory ion movements may represent a potential site for the regulation of the hormone-mediated Ca/sup 2 +/ signal.
A New Insight into Neutrino Energy Loss by Electron Capture of Iron Group Nuclei in Magnetar Surfaces
NASA Astrophysics Data System (ADS)
Liu, Jing-Jing; Gu, Wei-Min
Based on the relativistic mean-field effective interactions theory, and the Lai dong model, we discuss the influences of superstrong magnetic fields (SMFs) on electron Fermi energy, nuclear blinding energy, and single-particle level structure in magnetar surfaces. Using the Shell-Model Monte Carlo method and the Random Phase Approximation theory, we analyze the neutrino energy loss rates (NELRs) by electron capture for iron group nuclei in SMFs. First, when B 12 < 100, we find that the SMFs have a slight influence on the NELRs for most nuclides at relativistic low temperatures (e.g., T 9 = 0.233); nevertheless, the NELRs increase by more than four orders of magnitude at relativistic high temperatures (e.g., T 9 = 15.53). When B 12 > 100, the NELRs decrease by more than three orders of magnitude (e.g., at T 9 = 15.53 for 52–61Fe, 55–60Co, and 56–63Ni). Second, for a certain value of magnetic field and temperature, the NELRs increase by more than four orders of magnitude when {ρ }7≤slant {10}3, but as the density increases (i.e., when {ρ }7\\gt {10}3), there is almost no influence on the density of NELRs. For the density around {ρ }7={10}2, there is an abrupt increase in NELRs when B 12 ≥ 103.5. Such jumps are an indication that the underlying shell structure has changed due to single-particle behavior by SMFs. Finally, we compare our NELRs with those of Fuller et al. (FFN) and Nabi & Klapdor-Kleingrothaus (NKK). For the case without SMFs, one finds that our rates for certain nuclei are close to about five orders of magnitude lower than FFN and NKK at relativistic low temperatures (e.g., T 9 = 1). However, at a relativistic high temperature (e.g., T 9 = 3), our results are in good agreement with NKK, but about one order of magnitude lower than FFN. For the case with SMFs, our NELRs for some iron group nuclei can be about five orders of magnitude higher than those of FFN and NKK. (Note that B 12, T 9, and ρ 7 are in units of 1012 G, 109 K, and {10}7 {{g
Uranium, Thorium and some other trace elements in phosphorites from different provenances
NASA Astrophysics Data System (ADS)
Bech, J.; Reverter, F.; Tume, P.; Roca, N.; Suarez, E.; Sepúlveda, G.; Sokolovska, M.
Data on the trace element composition of phosphorites is scarce. Some of them may be harmful at certain concentrations. Special concern is given to the radionuclides U and Th and some other heavy metals such as: Co, Cr, Cu, Ni and V. Phosphorites of different origins can vary significantly in the trace element concentrations. 37 samples of phosphorites from 16 deposits were analyzed for Uranium, Thorium and five potential toxic elements (Co, Cr, Cu, Ni and V) as well as 26 samples of data gathered from the literature. In total 63 samples of phosphorites from 20 deposits of 19 countries were studied: Algeria, Australia, Brazil, Burkina Faso, Chile, Colombia, Egypt, India, Israel, Mongolia, Morocco, New Zealand, Peru, Senegal, Syria, Togo, Tunisia, USA and Venezuela. Aqua regia extracts were used to estimate the "pseudototal" values, following standard procedures (ISO 11466, 2002) and measured by ICP-MS. The median concentrations (mgkg-1) obtained were: U 53 (range 0.20-177), Th 4.05 (range 1-49), Co 4 (range 0.5-159), Cr 100 (range 15-1000), Cu 20 (range 5-213), Ni 21 (range 3-850) and V 70.05 (range 20-591). As 120 mgkg-1 of U concentration of phosphorites is the value considered to be useful as a source of nuclear fuel, we now indicate the deposits with values higher than 120 mgkg-1: Khouribga KIISB (Morocco) 121, Khouribga KIISL (Morocco) 123, Champ mines (Idaho, USA) 131, Noralyn (Central Florida, USA) 138, Bone Valley (Florida, USA) 140, Boucraa BGB (Morocco) 141, Boucraa BGC (Morocco) 152, Negev (Israel) 172 and Chatam Rise (New Zealand) 177. The highest Th concentration found was 49 mgkg-1 at Bijawar Group (India). Uranium shows significant positive correlations with V (r = 0.41) and Cr (r = 0.30), and significant negative correlations with Co (r= -0.47). Other positive correlations are Cr with Cu (r=0.58), Cr with V (r=0.52) and Cr with Ni (r=0.51). Cu correlates positively with Ni (r=0.84) and with V (r=0.63). Ni correlates positively with V (r=0.72).
Non-haem iron and the dissociation of piericidin A sensitivity from site 1 energy conservation in mitochondria from Torulopsis utilis
Clegg, R. A.; Garland, P. B.
1. The aerobic incubation of iron-deficient Torulopsis utilis cells for 12h under non-growing conditions results in the recovery by mitochondria of the previously absent site 1 energy conservation and sensitivity to piericidin A. 2. The recovery of piericidin A sensitivity but not site 1 is prevented by the presence of cycloheximide (100μg/ml) in the medium used for aerobic incubation of the cells. Rotenone sensitivity behaved similarly. 3. Chloramphenicol, erythromycin and tetracycline were without effect on the recovery of site 1 and piericidin A sensitivity. 4. Inclusion of 59Fe in the growth medium can be used as the basis for a highly sensitive assay for non-haem iron. 5. Iron-limited growth of T. utilis lowers the concentration of both non-haem iron and acid-labile sulphide of submitochondrial particles by over 20-fold compared with the `normal' situation with iron-supplemented glycerol-limited growth. 6. Increases in the non-haem iron and acid-labile sulphide concentrations of submitochondrial particles occur when site 1 and piericidin A sensitivity are recovered. The increase is approximately halved by the presence of cycloheximide. 7. The non-haem iron of T. utilis submitochondrial particles does not exchange with added iron. 8. Continuous culture of T. utilis at the transition between glycerol- and iron-limitation results in cells where mitochondria possess site 1 energy conservation but lack piericidin A sensitivity. 8. It is concluded, in contrast with widely held views to the opposite, that energy conservation at site 1 does not require electron flow to proceed through a piericidin A- or rotenone-sensitive route. 9. Restriction of the iron supplied to growing T. utilis to a concentration just above that required for growth limitation demonstrates that a 10- to 20-fold decrease of the `normal' non-haem iron concentration of both cells and mitochondria is without effect on the growth yield per unit of carbon source. Submitochondrial particles prepared
Kinetics of acute inflammation induced by Escherichia coli in rabbits. II. The effect of hyperimmunization, complement depletion, and depletion of leukocytes.
Kopaniak, M. M.; Movat, H. Z.
The inflammatory response to Escherichia coli was quantitated in the skin of normal rabbits and the kinetics established as described previously. Hyperemia, measured with radiolabeled microspheres; vascular permeability, estimated with 125 I-albumin; and leukocyte infiltration, quantitated with 51Cr-labeled autologous leukocytes, reached maximal values 3 hours after the injection of bacteria and subsided almost completely by 6 hours. Hemorrhage, measured with homologous 59Fe-erythrocytes, continued to increase between 1 and 6 hours after injection and then reached plateau levels. The lesions were studied up to 8 hours, since in the previous study no changes were observed beyond that time. In the study described in this paper, the host mediation systems were manipulated in various groups of rabbits in order to elucidate the mechanisms underlying the development of the inflammatory reaction. One group of animals was hyperimmunized with the E coli organisms, another was partially depleted of hemolytic complement with cobra venom factor, and yet another was rendered leukopenic with nitrogen mustard. In hyperimmunized animals hyperemia in the dermal lesions induced by the microorganisms was significantly more intense than in normal rabbits. Vascular permeability increase occurred earlier in hyperimmunized rabbits and at 1 hour was significantly greater than in normals. Decomplemented rabbits had significantly less vascular permeability than normal animals, whereas in leukopenic rabbits no increase in vascular permeability could be elicited. Leukocyte accumulation was increased over the normal animals in the lesions of hyperimmunized rabbits. Hemorrhage was significantly decreased in leukopenic rabbits. Histologic examination of the lesions revealed that whereas in normal animals the infiltrating neutrophils ingested most of the bacteria and formed definite abscesses by 6-8 hours, these abscesses were absent in leukopenic animals, and free-lying bacteria were
Alteration at translational but not transcriptional level of transferrin receptor expression following manganese exposure at the blood-CSF barrier in vitro
Li, G. Jane; Zhao Qiuqu; Zheng Wei . E-mail: email@example.com
Manganese exposure alters iron homeostasis in blood and cerebrospinal fluid (CSF), possibly by acting on iron transport mechanisms localized at the blood-brain barrier and/or blood-CSF barrier. This study was designed to test the hypothesis that manganese exposure may change the binding affinity of iron regulatory proteins (IRPs) to mRNAs encoding transferrin receptor (TfR), thereby influencing iron transport at the blood-CSF barrier. A primary culture of choroidal epithelial cells was adapted to grow on a permeable membrane sandwiched between two culture chambers to mimic blood-CSF barrier. Trace {sup 59}Fe was used to determine the transepithelial transport of iron. Following manganese treatment (100 {mu}M for 24 h), the initial flux rate constant (K {sub i}) of iron was increased by 34%, whereas the storage of iron in cells was reduced by 58%, as compared to controls. A gel shift assay demonstrated that manganese exposure increased the binding of IRP1 and IRP2 to the stem loop-containing mRNAs. Consequently, the cellular concentrations of TfR proteins were increased by 84% in comparison to controls. Assays utilizing RT-PCR, quantitative real-time reverse transcriptase-PCR, and nuclear run off techniques showed that manganese treatment did not affect the level of heterogeneous nuclear RNA (hnRNA) encoding TfR, nor did it affect the level of nascent TfR mRNA. However, manganese exposure resulted in a significantly increased level of TfR mRNA and reduced levels of ferritin mRNA. Taken together, these results suggest that manganese exposure increases iron transport at the blood-CSF barrier; the effect is likely due to manganese action on translational events relevant to the production of TfR, but not due to its action on transcriptional, gene expression of TfR. The disrupted protein-TfR mRNA interaction in the choroidal epithelial cells may explain the toxicity of manganese at the blood-CSF barrier.
Characterization of iron uptake from transferrin by murine endothelial cells.
Hallmann, R; Savigni, D L; Morgan, E H; Baker, E
Iron is required by the brain for normal function, however, the mechanisms by which it crosses the blood-brain barrier (BBB) are poorly understood. The uptake and efflux of transferrin (Tf) and Fe by murine brain-derived (bEND3) and lymph node-derived (m1END1) endothelial cell lines was compared. The effects of iron chelators, metabolic inhibitors and the cellular activators, lipopolysaccharide (LPS) and tumour necrosis factor-alpha (TNF-alpha), on Tf and Fe uptake were investigated. Cells were incubated with 59Fe-125I-Tf; Fe uptake was shown to increase linearly over time for both cell lines, while Tf uptake reached a plateau within 2 h. Both Tf and Fe uptake were saturable. bEND3 cells were shown to have half as many Tf receptors as m1END1 cells, but the mean cycling times of a Tf molecule were the same. Tf and Fe efflux from the cells were measured over time, revealing that after 2 h only 25% of the Tf but 80% of the Fe remained associated with the cells. Of 7 iron chelators, only deferriprone (L1) markedly decreased Tf uptake. However, Fe uptake was reduced by more than 50% by L1, pyridoxal isonicotinoyl hydrazone (PIH) and desferrithiocin (DFT). The cellular activators TNF-alpha or LPS had little effect on Tf turnover, but they accelerated Fe uptake in both endothelial cell types. Phenylarsenoxide (PhAsO) and N-ethyl maleimide (NEM), inhibitors of Tf endocytosis, reduced both Tf and Fe uptake in both cell lines, while bafilomycin A1, an inhibitor of endosomal acidification, reduced Fe uptake but did not affect Tf uptake. The results suggest that Tf and Fe uptake by both bEND3 and m1END1 is via receptor-mediated endocytosis with release of Fe from Tf within the cell and recycling of apo-Tf. On the basis of Tf- and Fe-metabolism both cell lines are similar and therefore well suited for use in in vitro models for Fe transport across the BBB. PMID:10865941
Mitochondrial iron accumulation exacerbates hepatic toxicity caused by hepatitis C virus core protein
Sekine, Shuichi; Ito, Konomi; Watanabe, Haruna; Nakano, Takafumi; Moriya, Kyoji; Shintani, Yoshizumi; Fujie, Hajime; Tsutsumi, Takeya; Miyoshi, Hideyuki; Fujinaga, Hidetake; Shinzawa, Seiko; Koike, Kazuhiko; Horie, Toshiharu
Patients with long-lasting hepatitis C virus (HCV) infection are at major risk of hepatocellular carcinoma (HCC). Iron accumulation in the livers of these patients is thought to exacerbate conditions of oxidative stress. Transgenic mice that express the HCV core protein develop HCC after the steatosis stage and produce an excess of hepatic reactive oxygen species (ROS). The overproduction of ROS in the liver is the net result of HCV core protein-induced dysfunction of the mitochondrial respiratory chain. This study examined the impact of ferric nitrilacetic acid (Fe-NTA)-mediated iron overload on mitochondrial damage and ROS production in HCV core protein-expressing HepG2 (human HCC) cells (Hep39b cells). A decrease in mitochondrial membrane potential and ROS production were observed following Fe-NTA treatment. After continuous exposure to Fe-NTA for six days, cell toxicity was observed in Hep39b cells, but not in mock (vector-transfected) HepG2 cells. Moreover, mitochondrial iron ({sup 59}Fe) uptake was increased in the livers of HCV core protein-expressing transgenic mice. This increase in mitochondrial iron uptake was inhibited by Ru360, a mitochondrial Ca{sup 2+} uniporter inhibitor. Furthermore, the Fe-NTA-induced augmentation of mitochondrial dysfunction, ROS production, and cell toxicity were also inhibited by Ru360 in Hep39b cells. Taken together, these results indicate that Ca{sup 2+} uniporter-mediated mitochondrial accumulation of iron exacerbates hepatocyte toxicity caused by the HCV core protein. - Highlights: • Iron accumulation in the livers of patients with hepatitis C virus (HCV) infection is thought to exacerbate oxidative stress. • The impact of iron overload on mitochondrial damage and ROS production in HCV core protein-expressing cells were examined. • Mitochondrial iron uptake was increased in the livers of HCV core protein-expressing transgenic mice. • Ca{sup 2+} uniporter-mediated mitochondrial accumulation of iron exacerbates
Alpha Production Cross Sections for Some Target Fusion Structural Materials up to 35 MeV
NASA Astrophysics Data System (ADS)
Yiğit, M.; Tel, E.
In the next century, because of the worldwide energy shortage, human life will badly be affected. Nuclear fusion energy is the remarkable solution to the rising energy challenges because it has the great potential for sustainability, economic and reliability. There have been many research and development studies to get energy from fusion. Moreover, the neutron induced reaction cross section data around 14-15 MeV are need to the design and development of nuclear fusion reactors. Thus, the working out the systematics of ( n, α) reaction cross sections is very important and necessary for the definition of the excitation curves at around 14-15 MeV energy. In this study, neutron induced reaction cross sections for structural fusion materials such as Sc ( Scandium), Co ( Cobalt), Ni ( Nickel), Cu ( Copper), Y ( Yttrium), Mo ( Molybdenum), Zr ( Zirconium) and Nb ( Niobium) have been investigated for the ( n, α) reactions. The new calculations on the excitation functions of 45 Sc( n, a) 42 K, 59 Co ( n, a) 56 Mn, 62 Ni( n, a) 59 Fe, 63 Cu( n, a) 60 Co, 65 Cu( n, a) 62 Co, 89 Y( n, a) 86 Rb, 92 Mo( n, a) 89 Zr, 98 Mo( n, a) 95 Zr, 92 Zr( n, a) 89 Sr, 94 Zr( n, a) 91 Sr and 93 Nb( n, a) 90 Y reactions have been carried out up to 35 MeV incident neutron energies. In these calculations, the pre-equilibrium and equilibrium effects have been investigated. The pre-equilibrium calculations involve the new evaluated the geometry dependent hybrid model, hybrid model and the cascade exciton model. The equilibrium effects of the excitation functions for the investigated reactions are calculated according to the Weisskopf-Ewing model. Additionaly, in the present work, the ( n, α) reaction cross sections have calculated by using evaluated empirical formulas developed by Tel et al. at 14-15 MeV energy. The calculated results have been discussed and compared with the available experimental data taken from EXFOR database.
River-derived humic substances as iron chelators in seawater
Krachler, Regina; Krachler, Rudolf F.; Wallner, Gabriele; Hann, Stephan; Laux, Monika; Cervantes Recalde, Maria F.; Jirsa, Franz; Neubauer, Elisabeth; von der Kammer, Frank; Hofmann, Thilo; Keppler, Bernhard K.
The speciation of iron(III) in oxic seawater is dominated by its hydrolysis and sedimentation of insoluble iron(III)-oxyhydroxide. As a consequence, many oceanic areas have very low iron levels in surface seawater which leads to iron deficiency since phytoplankton require iron as a micronutrient in order to grow. Fortunately, iron solubility is not truly as low as Fe(III) solubility measurements in inorganic seawater would suggest, since oceanic waters contain organic molecules which tend to bind the iron and keep it in solution. Various iron-binding organic ligands which combine to stabilize dissolved iron have been detected and thoroughly investigated in recent years. However, the role of iron-binding ligands from terrestrial sources remains poorly constrained. Blackwater rivers supply large amounts of natural organic material (NOM) to the ocean. This NOM (which consists mainly of vascular plant-derived humic substances) is able to greatly enhance iron bioavailability in estuaries and coastal regions, however, breakdown processes lead to a rapid decrease of river-derived NOM concentrations with increasing distance from land. It has therefore been argued that the influence of river-derived NOM on iron biogeochemistry in offshore seawater does not seem to be significant. Here we used a standard method based on 59Fe as a radiotracer to study the solubility of Fe(III)-oxyhydroxide in seawater in the presence of riverine NOM. We aimed to address the question how effective is freshwater NOM as an iron chelator under open ocean conditions where the concentration of land-derived organic material is about 3 orders of magnitude smaller than in coastal regions, and does this iron chelating ability vary between NOM from different sources and between different size fractions of the river-borne NOM. Our results show that the investigated NOM fractions were able to substantially enhance Fe(III)-oxyhydroxide solubility in seawater at concentrations of the NOM ≥ 5�
The major iron-containing protein of Legionella pneumophila is an aconitase homologous with the human iron-responsive element-binding protein.
Mengaud, J M; Horwitz, M A
Legionella pneumophila has high iron requirements, and its intracellular growth in human monocytes is dependent on the availability of intracellular iron. To learn more about iron metabolism in L. pneumophila, we have undertaken an analysis of the iron proteins of the bacterium. We first developed an assay to identify proteins by 59Fe labelling and nondenaturing polyacrylamide gel electrophoresis. The assay revealed seven iron proteins (IPs) with apparent molecular weights of 500, 450, 250, 210, 150, 130, and 85. IP150 comigrates with superoxide dismutase activity and is probably the Fe-superoxide dismutase of L. pneumophila. IP210 is the major iron-containing protein (MICP). To identify and characterize MICP, we purified the protein and cloned and sequenced its gene. MICP is a monomeric protein containing 891 amino acids, and it has a calculated molecular mass of 98,147 Da. Analysis of the sequence revealed that MICP has two interesting homologies. First, MICP is highly homologous with the human iron-responsive element-binding protein, consistent with the hypothesis that this critical iron-regulatory molecule of humans has a prokaryotic ancestor. Second, MICP is highly homologous with the Escherichia coli aconitase and to a lesser extent with porcine heart mitochondrial aconitase. Consistent with this, we found that MICP exhibits aconitase activity. In contrast to other aconitases, MICP has a single amino acid change of a potentially deleterious type at a site thought to be critical for substrate binding and enzymatic activity. However, the specific activity of MICP is roughly comparable to that of other aconitases, suggesting that the mutation has at most a mild effect on the aconitase activity of MICP. The abundance of MICP in L. pneumophila suggests either that L. pneumophila requires high aconitase and perhaps tricarboxylic acid cycle activity or that the bacterium requires large amounts of this protein to serve an additional role in bacterial physiology. A
Osumilite-(Mg): Validation as a mineral species and new data
NASA Astrophysics Data System (ADS)
Chukanov, N. V.; Pekov, I. V.; Rastsvetaeva, R. K.; Aksenov, S. M.; Belakovskiy, D. I.; Van, K. V.; Schüller, W.; Ternes, B.
Osumilite-(Mg), the Mg-dominant analogue of osumilite, has been approved by the CNMNC IMA as a new mineral species. The holotype sample has been found at Bellerberg, Eifel volcanic area, Germany. Fluorophlogopite, sanidine, cordierite, mullite, sillimanite, topaz, pseudobrookite and hematite are associated minerals. Osumilite-(Mg) occurs as short prismatic or thick tabular hexagonal crystals reaching 0.5 × 1 mm in size in the cavities in basaltic volcanic glasses at their contact with thermally metamorphosed xenoliths of pelitic rocks. The mineral is brittle, with Mohs' hardness 6.5. Cleavage was not observed. Color is blue to brown. D meas = 2.59(1), D calc = 2.595 g/cm3. No bands corresponding to H2O and OH-groups are in the IR spectrum. Osumilite-(Mg) is uniaxial (+), ω = 1.539(2), ɛ = 1.547(2). The chemical composition (electron microprobe, average of 5 point analyses, wt %) is: 0.08 Na2O, 3.41 K2O, 0.04 CaO, 7.98 MgO, 0.28 MnO, 21.57 Al2O3, 3.59 Fe2O3, 62.33 SiO2, total 99.28. The empirical formula is: (K0.72Na0.03Ca0.01)(Mg1.97Mn0.04)[Al4.21Fe{0.45/3+}Si10.32]O30. The simplified formula is: KMg2Al3(Al2Si10)O10. The crystal structure was refined on a single crystal, R = 0.0294. Osumilite-(Mg) is hexagonal, space group P6/ mcc; a = 10.0959(1), c = 14.3282(2)Å, V = 1264.79(6) Å3, Z = 2. The strongest reflections in the X-ray powder diffraction pattern [ d, Å I %) ( hkl)] are: 7.21 (37) (002), 5.064 (85) (110), 4.137 (45) (112), 3.736 (43) (202), 3.234 (100) (211), 2.932 (42) (114), 2.767 (51) (204). A type specimen is deposited in the Fersman Mineralogical Museum, Russian Academy of Sciences, Moscow, registration number 4174/1.
Developing Fieldable Systems for Chemical Sensing Using Field Asymmetric Ion Mobility Spectrometry and Mass Spectrometry
Kevin Kyle, Stephan Weeks, R. Trainham
Currently, there is an urgent need for field-rugged and field-programmable sensor systems that provide highly selective, universal monitoring of vapors and aerosols at detectable levels from persons or areas involved with illicit chemical/biological/explosives (CBE) production. These devices must be portable, low cost, robust, and provide accurate measurements to avoid both false positive and negative results. Furthermore, the information provided by the devices must be received in a timely manner so that informed decisions can be immediately made and the appropriate actions taken. Two technologies that are unparalleled in their sensitivity, selectivity, and trace-level detection capabilities are field asymmetric ion mobility spectrometry (FAIMS) and mass spectrometry. Here, we will show progress that has been made toward developing fieldable FAIMS systems and mass spectrometers. Working in collaboration with Sionex Corporation, the microDMx detector was equipped with a continuous air sampling system to develop selective methods for the analysis of compounds of interest. A microdiaphragm pump (KNF Neuberger, Inc.) is used to pull in gas-phase analytes directly from the air for separation and detection with the FAIMS system. The FAIMS evaluation platform (SVAC) unit currently measures 9.8-inch x 4.6-inch x 3.2-inch, weighs 3.1 lb, and utilizes a {sup 63}Ni source to ionize incoming compounds. Analytes entering the unit are separated and identified by their characteristic response to the compensation voltage (V{sub c}) at a given rf field strength (V{sub rf}). This response has been observed to be unique for a wide range of substances studied. If additional verification were required or a targeted analyte present in a complex chemical matrix, a FAIMS unit equipped with a fast gas chromatography column has been evaluated. The unit combines the separation capabilities of gas chromatography with the selectivity of FAIMS. It measures 9.5-inch x 5.25-inch x 3.5-inch
IIb trioctahedral chlorite from the Barberton greenstone belt: crystal structure and rock composition constraints with implications to geothermometry
NASA Astrophysics Data System (ADS)
Xie, Xiaogang; Byerly, Gary R.; Ferrell, Ray E., Jr.
IIb trioctahedral chlorite in the Barberton greenstone belt (BGB) metavolcanic rocks was formed during pervasive greenschist metamorphism. The chem-ical composition of the chlorite is highly variable, with the Fe/(Fe+Mg) ratio ranging from 0.12 to 0.8 among 53 samples. The chemical variation of the chlorite results from the chemical diversity of the host rock, especially the MgO content of the rock, but major details of the variation pattern of the chlorite are due to the crystal structure of the chlorite. All major cation abundances in the chlorite are strongly correlated with each other. Sil-icon increases with Mg and decreases with Fe, while AlIV and AlVI decrease with Mg and increase with Fe2+. A complex exchange vector explains over 90% of the chlorite compositional variation: Mg4SiFe2+-3AlVI-1 AlIV-1, which has 3 parts Fe-Mg substitution coupled with one part tschermakite substitution. This ratio is required to maintain the charge and site balances and the dimensional fit between the tetrahedral and octahedral sheets. The subtle change in Al substitution in chlorite implies that AlVI is preferentially ordered in the M(4) site, and about 84% of the AlVI present is in the M(4) sites when they are nearly filled with AlVI. Based on 47 analyzed chlorite-bearing rock samples, chlorite (Chl) composition is strongly correlated with the MgO content of the host rock. Calculated correlation coefficients are +0.91 for SiO2Chl-MgORock, -0.87 for Al2O3Chl-MgORock, +0.89 for MgOChl-MgORock, and -0.85 for FeOChl-MgORock. Only weak correlations have been found between chlorite oxides and other oxides of rock (between same oxides in chlorite and rock: SiO2-0.67, Al2O3+0.59, FeO -0.41). However, MgOChl is saturated at about 36 wt% in rocks that have MgO above 22 wt%.The MgOChl is about 5 wt% when the host rock approaches 0 wt% of MgO. This implies that Mg substituting into the chlorite is approximately limited to 1.5-9.2 Mg atoms per formula unit and 1.0-3.2 AlIV. Chlorite
Metals in agricultural produce associated with acid-mine drainage in Mount Morgan (Queensland, Australia).
Vicente-Beckett, Victoria A; McCauley, Gaylene J Taylor; Duivenvoorden, Leo J
Acid-mine drainage (AMD) into the Dee River from the historic gold and copper mine in Mount Morgan, Queensland (Australia) has been of concern to farmers in the area since 1925. This study sought to determine the levels of AMD-related metals and sulfur in agricultural produce grown near the mine-impacted Dee River, compare these with similar produce grown in reference fields (which had no known AMD influence), and assess any potential health risk using relevant Australian or US guidelines. Analyses of lucerne (Medicago sativa; also known as alfalfa) from five Dee fields showed the following average concentrations (mg/kg dry basis): Cd < 1, Cu 11, Fe 106, Mn 52, Pb < 5, Zn 25 and S 3934; similar levels were found in lucerne hay (used as cattle feed) from two Dee fields. All lucerne and lucerne hay data were generally comparable with levels found in the lucerne reference fields, suggesting no AMD influence; the levels were within the US National Research Council (US NRC) guidelines for maximum tolerable cattle dietary intake. Pasture grass (also cattle feed) from two fields in the Dee River floodplains gave mean concentrations (mg/kg dry) of Cd 0.14, Cu 12, Fe 313, Mn 111, Pb 1.4, Zn 86 and S 2450. All metal levels from the Dee and from reference sites were below the US NRC guidelines for maximum tolerable cattle dietary intake; however, the average Cd, Cu and Fe levels in Dee samples were significantly greater than the corresponding levels in the pasture grass reference sites, suggesting AMD influence in the Dee samples. The average levels in the edible portions of mandarin oranges (Citrus reticulata) from Dee sites (mg/kg wet weight) were Cd 0.011, Cu 0.59, Fe 2.2, Mn 0.56, Pb 0.18, S 91 and Zn 0.96. Cd and Zn were less than or close to, average Fe and Mn levels were at most twice, Cd 1.8 or 6.5 times, and Pb 8.5 or 72 times the maximum levels in raw oranges reported in the US total diet study (TDS) or the Australian TDS, respectively. Average Cd, Fe, Mn, Pb and
A Nanoparticulate Ferritin-Core Mimetic Is Well Taken Up by HuTu 80 Duodenal Cells and Its Absorption in Mice Is Regulated by Body Iron12
Latunde-Dada, Gladys O; Pereira, Dora IA; Tempest, Bethan; Ilyas, Hibah; Flynn, Angela C; Aslam, Mohamad F; Simpson, Robert J; Powell, Jonathan J
Background: Iron (Fe) deficiency anemia remains the largest nutritional deficiency disorder worldwide. How the gut acquires iron from nano Fe(III), especially at the apical surface, is incompletely understood. Objective: We developed a novel Fe supplement consisting of nanoparticulate tartrate-modified Fe(III) poly oxo-hydroxide [here termed nano Fe(III)], which mimics the Fe oxide core of ferritin and effectively treats iron deficiency anemia in rats. Methods: We determined transfer to the systemic circulation of nano Fe(III) in iron-deficient and iron-sufficient outbread Swiss mouse strain (CD1) mice with use of 59Fe-labeled material. Iron deficiency was induced before starting the Fe-supplementation period through reduction of Fe concentrations in the rodent diet. A control group of iron-sufficient mice were fed a diet with adequate Fe concentrations throughout the study. Furthermore, we conducted a hemoglobin repletion study in which iron-deficient CD1 mice were fed for 7 d a diet supplemented with ferrous sulfate (FeSO4) or nano Fe(III). Finally, we further probed the mechanism of cellular acquisition of nano Fe(III) by assessing ferritin formation, as a measure of Fe uptake and utilization, in HuTu 80 duodenal cancer cells with targeted inhibition of divalent metal transporter 1 (DMT1) and duodenal cytochrome b (DCYTB) before exposure to the supplemented iron sources. Differences in gene expression were assessed by quantitative polymerase chain reaction. Results: Absorption (means ± SEMs) of nano Fe(III) was significantly increased in iron-deficient mice (58 ± 19%) compared to iron-sufficient mice (18 ± 17%) (P = 0.0001). Supplementation of the diet with nano Fe(III) or FeSO4 significantly increased hemoglobin concentrations in iron-deficient mice (170 ± 20 g/L, P = 0.01 and 180 ± 20 g/L, P = 0.002, respectively). Hepatic hepcidin mRNA expression reflected the nonheme-iron concentrations of the liver and was also comparable for both nano Fe(III)– and