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The situation in which two level systems are present in a single-mode cavity is described by the Tavis–Cummings model
, which has Hamiltonian
Under the assumption that all two level systems have equal individual coupling strength to the field, the ensemble as a whole will have enhanced coupling strength . As a result, the vacuum Rabi splitting is correspondingly enhanced by a factor of . | 0 | Theoretical and Fundamental Chemistry |
Since 5β-coprostanol is formed from cholesterol in the vertebrate gut, the ratio of the product over reactant can be used to indicate the degree of faecal matter in samples. Raw untreated sewage typically has a 5β-coprostanol / cholesterol ratio of ~10 which decreases through a sewage treatment plant (STP) such that in the discharged liquid wastewaters the ratio is ~2. Undiluted STP wastewaters may be identified by this high ratio. As the faecal matter is dispersed in the environment, the ratio will decrease as more (non-faecal) cholesterol from animals is encountered. Grimalt & Albaiges () have suggested that samples with a 5β-coprostanol / cholesterol greater than 0.2 may be considered as contaminated by faecal material. | 1 | Applied and Interdisciplinary Chemistry |
After both minor losses and friction losses have been calculated, these values can be summed to find the total head loss.
Equation for total head loss, , can be simplified and rewritten as:
= Frictional head loss
= Downstream velocity
= Gravity of Earth
= Hydraulic radius
=Total length of piping
= Fanning friction factor
= Sum of all kinetic energy factors in system
Once calculated, the total head loss can be used to solve the Bernoulli Equation and find unknown values of the system. | 1 | Applied and Interdisciplinary Chemistry |
The concept of the theory is an extension of the Langmuir theory, which is a theory for monolayer molecular adsorption, to multilayer adsorption with the following hypotheses:
# gas molecules physically adsorb on a solid in layers infinitely;
# gas molecules only interact with adjacent layers; and
# the Langmuir theory can be applied to each layer.
# the enthalpy of adsorption for the first layer is constant and greater than the second (and higher).
# the enthalpy of adsorption for the second (and higher) layers is the same as the enthalpy of liquefaction.
The resulting BET equation is
where c is referred to as the BET C-constant, is the vapor pressure of the adsorptive bulk liquid phase which would be at the temperature of the adsorbate and θ is the surface coverage, defined as:
Here is the amount of adsorbate and is called the monolayer equivalent. The is the entire amount that would be present as a monolayer (which is theoretically impossible for physical adsorption) would cover the surface with exactly one layer of adsorbate. The above equation is usually rearranged to yield the following equation for the ease of analysis:
where and are the equilibrium and the saturation pressure of adsorbates at the temperature of adsorption, respectively; is the adsorbed gas quantity (for example, in volume units) while is the monolayer adsorbed gas quantity. is the BET constant,
where is the heat of adsorption for the first layer, and is that for the second and higher layers and is equal to the heat of liquefaction or heat of vaporization.
Equation (1) is an adsorption isotherm and can be plotted as a straight line with on the y-axis and on the x-axis according to experimental results. This plot is called a BET plot. The linear relationship of this equation is maintained only in the range of . The value of the slope and the y-intercept of the line are used to calculate the monolayer adsorbed gas quantity and the BET constant . The following equations can be used:
The BET method is widely used in materials science for the calculation of surface areas of solids by physical adsorption of gas molecules. The total surface area and the specific surface area are given by
where is in units of volume which are also the units of the monolayer volume of the adsorbate gas,
is the Avogadro number, the adsorption cross section of the adsorbate, the molar volume of the adsorbate gas, and the mass of the solid sample or adsorbent. | 0 | Theoretical and Fundamental Chemistry |
The cytochrome b6f complex is part of the thylakoid electron transport chain and couples electron transfer to the pumping of protons into the thylakoid lumen. Energetically, it is situated between the two photosystems and transfers electrons from photosystem II-plastoquinone to plastocyanin-photosystem I. | 0 | Theoretical and Fundamental Chemistry |
Umemoto reagents are (trifluoromethyl)dibenzoheterocyclic salts, such as 5-(trifluoromethyl)dibenzothiophenium triflate and 5-(trifluoromethyl)dibenzothiophenium tetrafluoroborate. | 0 | Theoretical and Fundamental Chemistry |
During extraction of the oil from oil sand, tailings consisting of water, silt, clays and other solvents are also created. This solid will become mature fine tailings by gravity. Foght et al (1985) estimated that there are 10 anaerobic heterotrophs and 10 sulfate-reducing prokaryotes per milliliter in the tailings pond, based on conventional most probable number methods. Foght set up an experiment with two tailings ponds and an analysis of the archaea, bacteria, and the gas released from tailings ponds showed that those were methanogens. As the depth increased, the moles of CH released actually decreased.
Siddique (2006, 2007) states that methanogens in the tailings pond live and reproduce by anaerobic degradation, which will lower the molecular weight from naphtha to aliphatic, aromatic hydrocarbons, carbon dioxide and methane. Those archaea and bacteria can degrade the naphtha, which was considered as waste during the procedure of refining oil. Both of those degraded products are useful. Aliphatic, aromatic hydrocarbons and methane can be used as fuel in the humans' daily lives. In other words, these methanogens improve the coefficient of utilization. Moreover, these methanogens change the structure of the tailings pond and help the pore water efflux to be reused for processing oil sands. Because the archaea and bacteria metabolize and release bubbles within the tailings, the pore water can go through the soil easily. Since they accelerate the densification of mature fine tailings, the tailings ponds are enabled to settle the solids more quickly so that the tailings can be reclaimed earlier. Moreover, the water released from the tailings can be used in the procedure of refining oil. Reducing the demand of water can also protect the environment from drought. | 1 | Applied and Interdisciplinary Chemistry |
If a beam of particles enters a thin layer of material of thickness , the flux of the beam will decrease by according to
where is the total cross section of all events, including scattering, absorption, or transformation to another species. The volumetric number density of scattering centers is designated by . Solving this equation exhibits the exponential attenuation of the beam intensity:
where is the initial flux, and is the total thickness of the material. For light, this is called the Beer–Lambert law. | 0 | Theoretical and Fundamental Chemistry |
* cyanonitrene - or (one of the nitrogens is univalent)
* azodicarbonitrile - or , cis and trans isomers
* cyanogen azide - or
* 1-diazidocarbamoyl-5-azidotetrazole -
* 2,2′-azobis(5-azidotetrazole) -
* triazidotriazine (cyanuric triazide) - ()
* triazidoheptazine - ()
* tricyanomethanimine (dicyanomethylene-cyanamide) - or
* diazidodicyanoethylene - or and , cis and trans
* dicyanodiazomethane - or
* - or (and isomers cyanoisocyanocarbene , diisocyanocarbene , 3-cyano-2H-azirenylidene and 3-isocyano-2H-azirenylidene)
* 1,3,5-triazido-2,4,6-tricyanobenzene - ()
* nitrogen tricyanide and carbon bis(cyanamide) , two formal monomers of polymeric | 0 | Theoretical and Fundamental Chemistry |
To distinguish between the different states of fluid flow one must consider how the fluid reacts to a disturbance in the initial state. These disturbances will relate to the initial properties of the system, such as velocity, pressure, and density. James Clerk Maxwell expressed the qualitative concept of stable and unstable flow nicely when he said:
That means that for a stable flow, any infinitely small variation, which is considered a disturbance, will not have any noticeable effect on the initial state of the system and will eventually die down in time. For a fluid flow to be considered stable it must be stable with respect to every possible disturbance. This implies that there exists no mode of disturbance for which it is unstable.
On the other hand, for an unstable flow, any variations will have some noticeable effect on the state of the system which would then cause the disturbance to grow in amplitude in such a way that the system progressively departs from the initial state and never returns to it. This means that there is at least one mode of disturbance with respect to which the flow is unstable, and the disturbance will therefore distort the existing force equilibrium. | 1 | Applied and Interdisciplinary Chemistry |
NbSn was discovered to be a superconductor in 1954, one year after the discovery of VSi, the first example of an AB superconductor. In 1961 it was discovered that niobium–tin still exhibits superconductivity at large currents and strong magnetic fields, thus becoming the first known material to support the high currents and fields necessary for making useful high-power magnets and electric power machinery. | 1 | Applied and Interdisciplinary Chemistry |
Phenolphthalein ( ) is a chemical compound with the formula CHO and is often written as "HIn", "HPh", "phph" or simply "Ph" in shorthand notation. Phenolphthalein is often used as an indicator in acid–base titrations. For this application, it turns colorless in acidic solutions and pink in basic solutions. It belongs to the class of dyes known as phthalein dyes.
Phenolphthalein is slightly soluble in water and usually is dissolved in alcohols in experiments. It is a weak acid, which can lose H ions in solution. The nonionized phenolphthalein molecule is colorless and the double deprotonated phenolphthalein ion is fuchsia. Further proton loss in higher pH occurs slowly and leads to a colorless form. Phenolphthalein ion in concentrated sulfuric acid is orange red due to sulfonation. | 0 | Theoretical and Fundamental Chemistry |
Yoon Nung-min (윤능민 尹能民, November 21, 1927 – April 1, 2009) is a South Korean chemist, known for his research in organic chemistry, specializing in metal hydrides.
He received his B.A. at Seoul National University in chemistry in 1951 and went on to complete his Ph.D. at Purdue University, under Herbert Charles Brown. He was a postdoc at Purdue, then a researcher for the Ministry of National Defence. He then became an associate professor at the Catholic University of Korea. He later took up full professorship at Sogang University, a position he would hold until his retirement. He served as the president of the Korean Chemical Society in 1989, and was elected a member of the National Academy of Sciences of the Republic of Korea in 2005. He was Professor Emeritus at Sogang University until his death in 2009.
He was a proficient researcher; he published 110 papers and developed reagents which became widely used in both organic and inorganic chemistry. He also discovered new methods of generating free radicals and found new applications. He surprised the Korean chemistry community by publishing a substantial portion of his research as the sole author shortly before his retirement.
He has also been active as an educator. He taught 14 doctorate students, and 56 masters students.
He was awarded the Order of Civil Merit (Mogryeon Medal) in 1983, Korea National Academy of Sciences Award in 1990 and the Korea Science Prize (Science) in 1993. | 0 | Theoretical and Fundamental Chemistry |
Preferential amplification is over-amplification of one of the alleles in comparison to the other. Most studies on MDA have reported this issue. The amplification bias is currently observed to be random. It might affect the analysis of small stretches of genomic DNA in identifying Short Tandem Repeats (STR) alleles. | 1 | Applied and Interdisciplinary Chemistry |
The influent in sewage water passes through a bar screen to remove all large objects like cans, rags, sticks, plastic packets, etc. carried in the sewage stream. This is most commonly done with an automated mechanically raked bar screen in modern plants serving large populations, while in smaller or less modern plants, a manually cleaned screen may be used. The raking action of a mechanical bar screen is typically paced according to the accumulation on the bar screens and/or flow rate. The solids are collected and later disposed in a landfill, or incinerated. Bar screens or mesh screens of varying sizes may be used to optimize solids removal. If gross solids are not removed, they become entrained in pipes and moving parts of the treatment plant, and can cause substantial damage and inefficiency in the process. | 1 | Applied and Interdisciplinary Chemistry |
By definition,
:1 reyn = 1 lb s in.
It follows that the relation between the reyn and the poise is approximately
:1 reyn = 6.89476 × 10 P.
In SI units, viscosity is expressed in newton-seconds per square meter, or equivalently in pascal-seconds. The conversion factor between the two is approximately
:1 reyn = 6890 Pa s. | 1 | Applied and Interdisciplinary Chemistry |
Tanning lamps, also known as tanning bulbs or tanning tubes, produce the ultraviolet light in tanning devices. The performance (or output) varies widely between brands and styles. Most are low-pressure fluorescent tubes, but high-pressure bulbs also exist. The electronics systems and number of lamps affect performance, but to a lesser degree than the lamp itself. Tanning lamps are regulated separately from tanning beds in most countries, as they are the consumable portion of the system. | 0 | Theoretical and Fundamental Chemistry |
Nonferrous archaeometallurgy in the southern Levant is the archaeological study of non-iron-related metal technology in the region of the Southern Levant during the Chalcolithic period and Bronze Age from approximately 4500BC to 1000BC. | 1 | Applied and Interdisciplinary Chemistry |
Ynols can interconvert with ketenes, much like enols can with aldehydes and ketones. The ynol tautomer is usually unstable, does not survive long, and changes into the ketene. This is because oxygen is more electronegative than carbon and thus forms stronger bonds. For instance, ethynol quickly interconverts with ethenone: | 0 | Theoretical and Fundamental Chemistry |
A study found that solar-energy-driven production of microbial foods from direct air capture substantially outperforms agricultural cultivation of staple crops in terms of land use. Growing such food from air yielded 10 times more protein and at least twice the calories than growing soybeans with the same amount of land.
A study complements life-cycle assessment studies, showing substantial deforestation reduction (56%) and climate change mitigation if only of per-capita beef was replaced by microbial protein by 2050.
Single cell protein (SCP) can substitute conventional protein feed. Land shortage and environmental calamities such as droughts or floods aren't a bottleneck in SCP production. | 1 | Applied and Interdisciplinary Chemistry |
The first mathematical study of the propagation of gravity currents can be attributed to T. B. Benjamin.
Observations of intrusions and collisions between fluids of differing density were made well before T. B. Benjamin's study, see for example those by Ellison and Tuner, by M. B. Abbot
or D. I. H. Barr.
J. E. Simpson from the Department of Applied Mathematics and Theoretical Physics of Cambridge University in the UK carried out longstanding research on gravity currents and issued a multitude of papers on the subject. He published an article
in 1982 for Annual Review of Fluid Mechanics which summarizes the state of research in the domain of gravity currents at the time. Simpson also published a more detailed book on the topic. | 1 | Applied and Interdisciplinary Chemistry |
*O dioxygen (acceptable name oxygen)
*O trioxygen (acceptable name ozone)
*P tetraphosphorus (acceptable name white phosphorus)
*S hexasulfur (acceptable name ε-sulfur)
*S cyclo-octasulfur (acceptable names for the polymorphic forms are α-sulfur, β-sulfur, γ-sulfur) | 0 | Theoretical and Fundamental Chemistry |
DNA banking is the secure, long term storage of an individual’s genetic material. DNA is most commonly extracted from blood, but can also be obtained from saliva and other tissues. DNA banks allow for conservation of genetic material and comparative analysis of an individuals genetic information. Analyzing an individuals DNA can allow scientists to predict genetic disorders, as used in preventive genetics or gene therapy, and prove that person's identity, as used in the criminal justice system. There are multiple methods for testing and analyzing genetic information including restriction fragment length polymorphism (RFLP) and polymerase chain reactions (PCR). | 1 | Applied and Interdisciplinary Chemistry |
Chemaxon () is a cheminformatics and bioinformatics software development company, headquartered in Budapest with 250 employees. The company also has offices in Cambridge, San Diego, Basel and in Prague. and it has distributors in China, India, Japan, South Korea, Singapore, and Australia. | 1 | Applied and Interdisciplinary Chemistry |
A pressure–volume diagram (or PV diagram, or volume–pressure loop) is used to describe corresponding changes in volume and pressure in a system. They are commonly used in thermodynamics, cardiovascular physiology, and respiratory physiology.
PV diagrams, originally called indicator diagrams, were developed in the 18th century as tools for understanding the efficiency of steam engines. | 0 | Theoretical and Fundamental Chemistry |
Human polypeptide C5a contains 74 amino acids and has 11kDa. NMR spectroscopy proved that the molecule is composed of four helices and connected by peptide loops with three disulphide bonds between helix IV and II, III. There is a short 1.5 turn helix on N-terminus but all agonist activity take place in the C-terminus. C5a is rapidly metabolised by a serum enzyme carboxypeptidase B to a 72 amino acid form C5a des-Arg without C terminal arginine. | 1 | Applied and Interdisciplinary Chemistry |
Rutherford is considered to be among the greatest scientists in history. At the opening session of the 1938 Indian Science Congress, which Rutherford had been expected to preside over before his death, astrophysicist James Jeans spoke in his place and deemed him "one of the greatest scientists of all time", saying: | 1 | Applied and Interdisciplinary Chemistry |
A typical mobile phase for HILIC chromatography includes acetonitrile ("MeCN", also designated as "ACN") with a small amount of water. However, any aprotic solvent miscible with water (e.g. THF or dioxane) can be used. Alcohols can also be used, however, their concentration must be higher to achieve the same degree of retention for an analyte relative to an aprotic solvent–water combination. See also Aqueous normal phase chromatography.
It is commonly believed that in HILIC, the mobile phase forms a water-rich layer on the surface of the polar stationary phase vs. the water-deficient mobile phase, creating a liquid/liquid extraction system. The analyte is distributed between these two layers. However, HILIC is more than just simple partitioning and includes hydrogen donor interactions between neutral polar species as well as weak electrostatic mechanisms under the high organic solvent conditions used for retention. This distinguishes HILIC as a mechanism distinct from ion exchange chromatography. The more polar compounds will have a stronger interaction with the stationary aqueous layer than the less polar compounds. Thus, a separation based on a compound's polarity and degree of solvation takes place. | 1 | Applied and Interdisciplinary Chemistry |
In molecular biology the protein domain S-adenosylmethionine synthetase N terminal domain is found at the N-terminal of the enzyme. | 1 | Applied and Interdisciplinary Chemistry |
Ambident dienophile 57 reacts with DAPC 54 at the cyclobutene π-bond to produce ligand 58; in contrast, the related ambident dienophile 59 reacts with DAPC 54 at the naphthoquinone π-center to produce adduct 60 (lack of shielding of the methylene protons supports the stereochemical assignment). | 0 | Theoretical and Fundamental Chemistry |
Torreyanic acid is a dimeric quinone first isolated and by Lee et al. in 1996 from an endophyte, Pestalotiopsis microspora. This endophyte is likely the cause of the decline of Florida torreya (Torreya taxifolia), an endangered species that is related to the taxol-producing Taxus brevifolia. The natural product was found to be cytotoxic against 25 different human cancer cell lines with an average IC50 value of 9.4 µg/mL, ranging from 3.5 (NEC) to 45 (A549) µg/mL. Torreyanic acid was found to be 5-10 times more potent in cell lines sensitive to protein kinase C (PKC) agonists, 12-o-tetradecanoyl phorbol-13-acetate (TPA), and was shown to cause cell death via apoptosis. Torreyanic acid also promoted G1 arrest of G0 synchronized cells at 1-5 µg/mL levels, depending on the cell line. It has been proposed that the eukaryotic translation initiation factor EIF-4a is a potential biochemical target for the natural compound. | 0 | Theoretical and Fundamental Chemistry |
There are a few unusual circumstances where speleothems have been created in caves as a result of hyperalkaline leachate, with the same chemistry as occurs in [Equations to ]. This chemistry can occur when there is a source of concrete, lime, mortar or other manmade calcareous material located above a cave system and the associated hyperalkaline leachate can penetrate into the cave below. An example can be found in the Peak District – Derbyshire, England where pollution from 19th century industrial lime production has leached into the cave system below (e.g. Poole's Cavern) and created speleothems, such as stalactites and stalagmites. | 1 | Applied and Interdisciplinary Chemistry |
In 2006, the wells of a neighborhood in Jacksonville, Maryland, were contaminated by a spill of 26,000 gallons of gasoline from an Exxon-Mobil station in the area, resulting in an ongoing court battle. The suit has been filed by the state of Marylands Department of the Environment on behalf of the areas residents, seeking millions of dollars in damages from Exxon-Mobil. Many residents also filed their own separate lawsuits.
The case began in 2006, when a gasoline tank sprang a leak that was not detected for 34 days. Testing of 120 wells resulted in dangerously high levels of MTBE being found. Residents were put in danger by the spill, and in order to prevent further health problems, they required bottled water for cooking, drinking, and brushing teeth. Residents of Jacksonville continue to use bottled water for all activities despite having MTBE filters and alarms installed in their homes. Home values also dropped as a result of the spill.
In September 2008, Exxon-Mobil settled the case with the state by agreeing to pay a $4 million fine, and face an additional $1 million in penalties annually if they did not work to clean up the spill.
In March 2009, a jury awarded $150 million in damages to some of the area's residents. The jury did not assess any punitive damages in the case, finding that Exxon Mobil did not act fraudulently. A separate case including over 150 property owners as plaintiffs began in early 2011. Punitive damages were awarded to the second group of plaintiffs, on the basis that Exxon acted fraudulently, however this decision was later reversed. | 1 | Applied and Interdisciplinary Chemistry |
If an initially isolated physical system, without internal walls that establish adiabatically isolated subsystems, is left long enough, it will usually reach a state of thermal equilibrium in itself, in which its temperature will be uniform throughout, but not necessarily a state of thermodynamic equilibrium, if there is some structural barrier that can prevent some possible processes in the system from reaching equilibrium; glass is an example. Classical thermodynamics in general considers idealized systems that have reached internal equilibrium, and idealized transfers of matter and energy between them.
An isolated physical system may be inhomogeneous, or may be composed of several subsystems separated from each other by walls. If an initially inhomogeneous physical system, without internal walls, is isolated by a thermodynamic operation, it will in general over time change its internal state. Or if it is composed of several subsystems separated from each other by walls, it may change its state after a thermodynamic operation that changes its walls. Such changes may include change of temperature or spatial distribution of temperature, by changing the state of constituent materials. A rod of iron, initially prepared to be hot at one end and cold at the other, when isolated, will change so that its temperature becomes uniform all along its length; during the process, the rod is not in thermal equilibrium until its temperature is uniform. In a system prepared as a block of ice floating in a bath of hot water, and then isolated, the ice can melt; during the melting, the system is not in thermal equilibrium; but eventually, its temperature will become uniform; the block of ice will not re-form. A system prepared as a mixture of petrol vapour and air can be ignited by a spark and produce carbon dioxide and water; if this happens in an isolated system, it will increase the temperature of the system, and during the increase, the system is not in thermal equilibrium; but eventually, the system will settle to a uniform temperature.
Such changes in isolated systems are irreversible in the sense that while such a change will occur spontaneously whenever the system is prepared in the same way, the reverse change will practically never occur spontaneously within the isolated system; this is a large part of the content of the second law of thermodynamics. Truly perfectly isolated systems do not occur in nature, and always are artificially prepared. | 0 | Theoretical and Fundamental Chemistry |
When a defective gene causes gaps to appear in the metabolic recycling process for purines and pyrimidines, these chemicals are not metabolised properly, and adults or children can suffer from any one of twenty-eight hereditary disorders, possibly some more as yet unknown. Symptoms can include gout, anaemia, epilepsy, delayed development, deafness, compulsive self-biting, kidney failure or stones, or loss of immunity.
Purine metabolism can have imbalances that can arise from harmful nucleotide triphosphates incorporating into DNA and RNA which further lead to genetic disturbances and mutations, and as a result, give rise to several types of diseases. Some of the diseases are:
#Severe immunodeficiency by loss of adenosine deaminase.
#Hyperuricemia and Lesch–Nyhan syndrome by the loss of hypoxanthine-guanine phosphoribosyltransferase.
#Different types of cancer by an increase in the activities of enzymes like IMP dehydrogenase. | 1 | Applied and Interdisciplinary Chemistry |
Slayton Alvin Evans Jr. was born on May 17, 1943, in Chicago, Illinois, to Corine M. Thompson Evans and Slayton A. Evans, Sr. Months later, his father was called to serve in World War II. When Slayton was three years old, the family moved to Meridian, Mississippi, where they lived in a segregated public housing project and his father worked at a J. C. Penney store. Slaytons interest in chemistry began early, when he was given a chemistry set. In addition, a small microscope allowed him to study various plant specimens and insects. Evans and his two younger siblings enrolled at a segregated primary school run by the Roman Catholic Church, and later he attended St. Josephs High School. In 1957, when Evans was in the ninth grade, news of the artificial satellite Sputnik inspired him to learn about rocketry and attempt to build his own. While he was given permission by the nuns at his school to buy chemicals to make rocket fuel, he had to make his own powdered charcoal. He built six rockets, two of them achieving liftoff.
Evans helped pay for his school tuition by mowing lawns and during eighth grade he was a junior assistant janitor at his elementary school. Later he worked in the high school cafeteria. In his third year of high school, he considered going into the Air Force, but was too tall for flight training. However, he took several competitive examinations and was the recipient of an academic scholarship to Tougaloo College where he also received an athletic scholarship for basketball. He enrolled at Tougaloo in 1961.
By the end of his first year, Evans had top marks in chemistry in his class. He got a summer job working for the pharmaceutical company Abbott Laboratories in Chicago where he was tasked first with creating chemical compounds from raw materials, and later with identifying the stages of chemical reactions. Evans graduated from Tougaloo with a Bachelor of Science in chemistry in 1965. Evans was encouraged to attend graduate school, though he didnt know how to pay for it. He briefly attended the Illinois Institute of Technology before transferring to Case Western Reserve University in Cleveland, Ohio, where he was offered a research assistant position in the chemistry department. In his first year, he received a draft notice to go to the Vietnam War. University officials contacted the draft board and explained that Evans research was crucial to the war effort. He was researching a medicine to treat schistosomiasis, a disease caused by parasitic flatworms that are common in Southeast Asia. He completed his coursework in 1969 and received his Ph.D. in chemistry in early 1970. | 0 | Theoretical and Fundamental Chemistry |
Black light is used extensively in non-destructive testing. Fluorescing fluids are applied to metal structures and illuminated with a black light which allows cracks and other weaknesses in the material to be easily detected.
In addition, if a leak is suspected in a refrigerator or an air conditioning system, a UV tracer dye can be injected into the system along with the compressor lubricant oil and refrigerant mixture. The system is then run in order to circulate the dye across the piping and components and then the system is examined with a blacklight lamp. Any evidence of fluorescent dye then pinpoints the leaking part which needs replacement. | 0 | Theoretical and Fundamental Chemistry |
Brominated vegetable oil (BVO) is a complex mixture of plant-derived triglycerides that have been modified by atoms of the element bromine bonded to the fat molecules. Brominated vegetable oil is used to help emulsify citrus-flavored soft drinks, preventing them from separating during distribution. Brominated vegetable oil has been used by the soft drink industry since 1931, generally at a level of about 8 ppm.
Careful control of the type of oil used allows bromination of it to produce BVO with a specific density of 1.33 g/mL, which is 33% greater than water (1 g/mL). As a result, it can be mixed with less-dense flavoring agents such as citrus oil to produce an oil which matches the density of water or other products. The droplets containing BVO remain suspended in the water rather than separating and floating to the surface.
Alternative food additives used for the same purpose include sucrose acetate isobutyrate (SAIB, E444) and glycerol ester of wood rosin (ester gum, E445).
Similar iodinated oils have been used as contrast agents and for goiter prophylaxis in populations with low dietary iodine intake.
Brominated vegetable oil has the CAS number 8016-94-2 and the EC number 232-416-5. | 0 | Theoretical and Fundamental Chemistry |
A good example of green infrastructure principles being applied at landscape scale is the Beijing Olympic site. First developed for the 2008 Summer Olympics but used also for the 2022 Winter Olympics, the Beijing Olympic site covers a large area of brownfield redevelopment in the northern sector of the city between the 4th and 5th ring roads. The central green infrastructure feature of the Olympic site is the "Dragon-shaped river" – a complex of retention basins and wetlands covering more than a half million square metres configured to look from the air like a traditional Chinese dragon.
In addition to referencing Chinese culture, the system is capable of significantly reducing nutrient loads from influent waters, which are provided by a nearby wastewater recycling facility. | 1 | Applied and Interdisciplinary Chemistry |
:Diffraction patterns collected through PED often agree well-enough with the kinematical pattern to serve as input data for direct methods calculations. A three-dimensional set of intensities mapped over the reciprocal lattice can be generated by collecting diffraction patterns over multiple zone axes. Applying direct methods to this data set will then yield probable crystal structures. Coupling direct methods results with simulations (e.g. multislice) and iteratively refining the solution can lead to the ab initio determination of the crystal structure.
:The PED technique has been used to determine the crystal structure of many classes of materials. Initial investigations during the emergence of the technique focused on complex oxides and nano-precipitates in Aluminum alloys that could not be resolved using x-ray diffraction. Since becoming a more widespread crystallographic technique, many more complex metal oxide structures have been solved.
:Zeolites are a technologically valuable class of materials that have historically been difficult to solve using x-ray diffraction due to the large unit cells that typically occur. PED has been demonstrated to be a viable alternative to solving many of these structures, including the ZSM-10, MCM-68, and many of the ITQ-n class of zeolite structures.
:PED also enables the use of electron diffraction to investigate beam-sensitive organic materials. Because PED can reproduce symmetric zone axis diffraction patterns even when the zone axis is not perfectly aligned, it enables information to be extracted from sensitive samples without risking overexposure during a time-intensive orientation of the sample. | 0 | Theoretical and Fundamental Chemistry |
An organ-on-a-chip (OOC) is a multi-channel 3-D microfluidic cell culture, integrated circuit (chip) that simulates the activities, mechanics and physiological response of an entire organ or an organ system. It constitutes the subject matter of significant biomedical engineering research, more precisely in bio-MEMS. The convergence of labs-on-chips (LOCs) and cell biology has permitted the study of human physiology in an organ-specific context. By acting as a more sophisticated in vitro approximation of complex tissues than standard cell culture, they provide the potential as an alternative to animal models for drug development and toxin testing.
Although multiple publications claim to have translated organ functions onto this interface, the development of these microfluidic applications is still in its infancy. Organs-on-chips vary in design and approach between different researchers. Organs that have been simulated by microfluidic devices include brain, lung, heart, kidney, liver, prostate, vessel (artery), skin, bone, cartilage and more.
A limitation of the early organ-on-a-chip approach is that simulation of an isolated organ may miss significant biological phenomena that occur in the body's complex network of physiological processes, and that this oversimplification limits the inferences that can be drawn. Many aspects of subsequent microphysiometry aim to address these constraints by modeling more sophisticated physiological responses under accurately simulated conditions via microfabrication, microelectronics and microfluidics.
The development of organ chips has enabled the study of the complex pathophysiology of human viral infections. An example is the liver chip platform that has enabled studies of viral hepatitis. | 1 | Applied and Interdisciplinary Chemistry |
FutureGen was a project to demonstrate capture and sequestration of waste carbon dioxide from a coal-fired electrical generating station. The project (renamed FutureGen 2.0) was retrofitting a shuttered coal-fired power plant in Meredosia, Illinois, with oxy-combustion generators. The waste CO would be piped approximately to be sequestered in underground saline formations. FutureGen was a partnership between the United States government and an alliance of primarily coal-related corporations. Costs were estimated at US$1.65 billion, with $1.0 billion provided by the Federal Government.
First announced by President George W. Bush in 2003, construction started in 2014 after restructuring, canceling, relocating, and restarting. Citing an inability to commit and spend the funds by deadlines in 2015, the Department of Energy withdrew funds and suspended FutureGen 2.0 in February, 2015. The government also cited the Alliance's inability to raise the requisite amount of private funding. The Meredosia power plant that had been planned for retrofit was demolished around 2021.
FutureGen 2.0 would have been the most comprehensive Department of Energy Carbon Capture and Storage demonstration project, involving all phases from combustion to sequestration. FutureGen's initial plan involved integrated gasification combined cycle technology to produce both electricity and hydrogen. Early in the project it was to be sited in Mattoon, IL. | 1 | Applied and Interdisciplinary Chemistry |
Gestonorone caproate is the generic name of the drug and its , , and , while gestronol hexanoate is its . It has also been referred to as norhydroxyprogesterone caproate, and is also known by its former developmental code names SH-582 and SH-80582. | 0 | Theoretical and Fundamental Chemistry |
The alloys did not prove to be commercially successful in the long run. However, during World War I and afterwards, uranium-doped steels were used for tools; large amounts of ferrouranium were produced between 1914 and 1916. | 1 | Applied and Interdisciplinary Chemistry |
The jiva is believed to rely on other dravya to function. The Jain philosophy completely separates body (matter) from the soul (consciousness). Souls reside in bodies and journey endlessly through saṃsāra (that is, realms of existence through cycles of rebirths and redeaths). Ajiva consists of everything other than jiva. Life processes such as breath means of knowledge such as language, all emotional and biological experiences such as pleasure and pain are all believed in Jainism to be made of pudgala (matter). These interact with tattva or reality to create, bind, destroy or unbind karma particles to the soul. According to Dundas, Dharma as a metaphysical substance in Jain philosophy may be understood as "that which carries" instead of the literal sense of ordinary physical motion. Thus, dharma includes all verbal and mental activity that contributes to karma and purification of the soul. | 1 | Applied and Interdisciplinary Chemistry |
Davis reagent (3-phenyl-2-(phenylsulfonyl)-1,2-oxaziridine or 2-(benzenesulfonyl)-3-phenyloxaziridine) is a reagent used for oxidation in the Davis oxidation reaction, as well as oxidation of thiols to sulfones. It is named for Franklin A. Davis. | 0 | Theoretical and Fundamental Chemistry |
Ecologically, V. fischeri is known to have symbiotic associations with a number of eukaryotic hosts, including the Hawaiian Bobtail Squid (Euprymna scolopes). In this relationship, the squid host maintains the bacteria in specialized light organs. The host provides a safe, nutrient rich environment for the bacteria and in turn, the bacteria provide light. Although bioluminescence can be used for mating and other purposes, in E. scolopes it is used for counter illumination to avoid predation.
The autoinducer molecule used by V. fischeri is N-(3-oxohexanoyl)-homoserine lactone. This molecule is produced in the cytoplasm by the LuxI synthase enzyme and is secreted through the cell membrane into the extracellular environment. As is true of most autoinducers, the environmental concentration of N-(3-oxohexanoyl)-homoserine lactone is the same as the intracellular concentration within each cell. N-(3-oxohexanoyl)-homoserine lactone eventually diffuses back into cells where it is recognized by LuxR once a threshold concentration (~10 μg/ml) has been reached. LuxR binds the autoinducer and directly activates transcription of the luxICDABE operon. This results in an exponential increase in both the production of autoinducer and in bioluminescence. LuxR bound by autoinducer also inhibits the expression of luxR, which is thought to provide a negative feedback compensatory mechanism to tightly control levels of the bioluminescence genes. | 1 | Applied and Interdisciplinary Chemistry |
Coenzyme A (CoA, SHCoA, CoASH) is a coenzyme, notable for its role in the synthesis and oxidation of fatty acids, and the oxidation of pyruvate in the citric acid cycle. All genomes sequenced to date encode enzymes that use coenzyme A as a substrate, and around 4% of cellular enzymes use it (or a thioester) as a substrate. In humans, CoA biosynthesis requires cysteine, pantothenate (vitamin B), and adenosine triphosphate (ATP).
In its acetyl form, coenzyme A is a highly versatile molecule, serving metabolic functions in both the anabolic and catabolic pathways. Acetyl-CoA is utilised in the post-translational regulation and allosteric regulation of pyruvate dehydrogenase and carboxylase to maintain and support the partition of pyruvate synthesis and degradation. | 1 | Applied and Interdisciplinary Chemistry |
Ferrier was elected Fellow of the Royal Society of New Zealand (1977) and the New Zealand Institute of Chemistry (1972) and awarded a DSc (London, 1968). | 0 | Theoretical and Fundamental Chemistry |
Blocking antibodies can be used in a variety of medical and scientific manners, thus far been to treat cancer, Graves' disease, and prevent the growth of malaria in mosquitoes. | 1 | Applied and Interdisciplinary Chemistry |
In the first step, a delocalized allyloxocarbenium ion (2) is formed, typically with the aid of a Lewis acid like indium(III) chloride or boron trifluoride. This ion reacts in situ with an alcohol, yielding a mixture of the α (3) and β (4) anomers of the 2-glycoside, with the double bond shifted to position 3,4. | 0 | Theoretical and Fundamental Chemistry |
The oldest anodizing process uses chromic acid. It is widely known as the Bengough-Stuart process but, due to the safety regulations regarding air quality control, is not preferred by vendors when the additive material associated with type II doesn't break tolerances. In North America, it is known as Type I because it is so designated by the MIL-A-8625 standard, but it is also covered by AMS 2470 and MIL-A-8625 Type IB. In the UK it is normally specified as Def Stan 03/24 and used in areas that are prone to come into contact with propellants etc. There are also Boeing and Airbus standards. Chromic acid produces thinner, 0.5 μm to 18 μm (0.00002" to 0.0007") more opaque films that are softer, ductile, and to a degree self-healing. They are harder to dye and may be applied as a pretreatment before painting. The method of film formation is different from using sulfuric acid in that the voltage is ramped up through the process cycle. | 1 | Applied and Interdisciplinary Chemistry |
Dynamic covalent chemistry (DCvC) is a synthetic strategy employed by chemists to make complex molecular and supramolecular assemblies from discrete molecular building blocks. DCvC has allowed access to complex assemblies such as covalent organic frameworks, molecular knots, polymers, and novel macrocycles. Not to be confused with dynamic combinatorial chemistry, DCvC concerns only covalent bonding interactions. As such, it only encompasses a subset of supramolecular chemistries.
The underlying idea is that rapid equilibration allows the coexistence of a variety of different species among which molecules can be selected with desired chemical, pharmaceutical and biological properties. For instance, the addition of a proper template will shift the equilibrium toward the component that forms the complex of higher stability (thermodynamic template effect). After the new equilibrium is established, the reaction conditions are modified to stop equilibration. The optimal binder for the template is then extracted from the reactional mixture by the usual laboratory procedures. The property of self-assembly and error-correcting that allow DCvC to be useful in supramolecular chemistry rely on the dynamic property. | 0 | Theoretical and Fundamental Chemistry |
A futile cycle, also known as a substrate cycle, occurs when two metabolic pathways run simultaneously in opposite directions and have no overall effect other than to dissipate energy in the form of heat. The reason this cycle was called "futile" cycle was because it appeared that this cycle operated with no net utility for the organism. As such, it was thought of being a quirk of the metabolism and thus named a futile cycle. After further investigation it was seen that futile cycles are very important for regulating the concentrations of metabolites. For example, if glycolysis and gluconeogenesis were to be active at the same time, glucose would be converted to pyruvate by glycolysis and then converted back to glucose by gluconeogenesis, with an overall consumption of ATP. Futile cycles may have a role in metabolic regulation, where a futile cycle would be a system oscillating between two states and very sensitive to small changes in the activity of any of the enzymes involved. The cycle does generate heat, and may be used to maintain thermal homeostasis, for example in the brown adipose tissue of young mammals, or to generate heat rapidly, for example in insect flight muscles and in hibernating animals during periodical arousal from torpor. It has been reported that the glucose metabolism substrate cycle is not a futile cycle but a regulatory process. For example, when energy is suddenly needed, ATP is replaced by AMP, a much more reactive adenine. | 1 | Applied and Interdisciplinary Chemistry |
ILs can aid the recycling of synthetic goods, plastics, and metals. They offer the specificity required to separate similar compounds from each other, such as separating polymers in plastic waste streams. This has been achieved using lower temperature extraction processes than current approaches and could help avoid incinerating plastics or dumping them in landfill. | 0 | Theoretical and Fundamental Chemistry |
In analogy to the rule of five, it has been proposed that ideal fragments should follow the rule of three (molecular weight < 300, ClogP < 3, the number of hydrogen bond donors and acceptors each should be < 3 and the number of rotatable bonds should be < 3). Since the fragments have relatively low affinity for their targets, they must have high water solubility so that they can be screened at higher concentrations. | 1 | Applied and Interdisciplinary Chemistry |
*President-Royal Australian Chemical Institute (Queensland Division)
*Chair, International Relations Committee of RACI
*Member, National Committee for Chemistry
*Executive Secretary, World Chemistry Congress/IUPAC General Assembly (2001)
*Chair, Board of Australian Science Innovations
*Organiser, Chemistry-Biotechnology Symposium at World Chemistry Congress (Torino, 2007); 27th International Symposium on the Chemistry of Natural Products (Brisbane, 2011)
*Organiser, Women sharing a Chemical Moment in Time, International Year of Chemistry (2011)
*Leadership roles in Division III (organic and biomolecular) of International Union of Pure and Applied Chemistry (IUPAC) as Titular Member (2006-2007), Secretary (2008-2011), President-elect (2012–2013), Division President and Bureau Member (2014–2015), then as Past-President (2016-2017)
*Elected to Membership of the Bureau of the International Union of Pure and Applied Chemistry (2018-2021)
*Co-chair IUPAC100 (centennial) Management Committee (2016-2019)
*Co-convenor of Women's Global Breakfast networking event held in over 100 countries since 2019; the theme for the 2024 breakfast event on February 27 is "Catalyzing Change in Chemistry"
*Incoming Vice-President/President-elect, and Chair of the Science Board, of the International Union of Pure and Applied Chemistry for 2024-2025 | 0 | Theoretical and Fundamental Chemistry |
In a reaction that is typically avoided, hydrolysis of carbamoyl chlorides gives carbamic acids:
:RNCOCl + HO → RNC(O)OH + HCl
Owing to the influence of the amino group, these compounds are less hydrolytically sensitive than the usual acid chlorides.
A related but more useful reaction is the analogous reaction with alcohols:
:RNCOCl + ROH + CHN → RNC(O)OR + CHNHCl | 0 | Theoretical and Fundamental Chemistry |
A monitor in the cockpit displays detailed images in real time, and the system also logs the image and Global Positioning System data at a rate of 30 gigabytes (GB) per hour for later analysis. The on-board data processing system performs numerous real-time processing functions including data acquisition and recording, raw data correction, target detection, cueing and chipping, precision image geo-registration, and display and dissemination of image products and target cue information.
ARCHER has three methods for locating targets:
* signature matching where reflected light is matched to spectral signatures
* anomaly detection using a statistical model of the pixels in the image to determine the probability that a pixel does not match the profile, and
* change detection which executes a pixel-by-pixel comparison of the current image against ground conditions that were obtained in a previous mission over the same area.
In change detection, scene changes are identified, and new, moved or departed targets are highlighted for evaluation. In spectral signature matching, the system can be programmed with the parameters of a missing aircraft, such as paint colors, to alert the operators of possible wreckage. It can also be used to look for specific materials, such as petroleum products or other chemicals released into the environment, or even ordinary items like commonly available blue polyethylene tarpaulins. In an impact assessment role, information on the location of blue tarps used to temporarily repair buildings damaged in a storm can help direct disaster relief efforts; in a counterdrug role, a blue tarp located in a remote area could be associated with illegal activity. | 0 | Theoretical and Fundamental Chemistry |
In the absence of hypoxic conditions (i.e. physiological levels of oxygen), cancer cells preferentially convert glucose to lactate, according to Otto H. Warburg, who believed that aerobic glycolysis was the key metabolic change in cancer cell malignancy. The "Warburg effect" was later coined to describe this metabolic shift. Warburg thought this change in metabolism was due to mitochondrial "respiration injury", but this interpretation was questioned by other researchers in 1956 showing that intact and functional cytochromes detected in most tumor cells clearly speak against a general mitochondrial dysfunction. Furthermore, Potter et al. and several other authors provided significant evidence that oxidative phosphorylation and a normal Krebs cycle persist in the vast majority malignant tumors, adding to the growing body of evidence that most cancers exhibit the Warburg effect while maintaining a proper mitochondrial respiration. Dang et al. in 2008 provided evidence that the tumor tissue sections used in Warburgs experiments should have been thinner for the oxygen diffusion constants employed, implying that the tissue slices studied were partially hypoxic and the calculated critical diffusion distance was of 470 micrometers. As a result, endless debates and discussions about Warburgs discovery took place and have piqued the interest of scientists all over the world, which has helped bring attention to cell metabolism in cancer and immune cells and the use of modern technology to discover what these pathways are and how they are modified as well as potential therapeutic targets. | 1 | Applied and Interdisciplinary Chemistry |
Fractoluminescence is often used as a synonym for triboluminescence. It is the emission of light from the fracture (rather than rubbing) of a crystal, but fracturing often occurs with rubbing. Depending upon the atomic and molecular composition of the crystal, when the crystal fractures, a charge separation can occur, making one side of the fractured crystal positively charged and the other side negatively charged. Like in triboluminescence, if the charge separation results in a large enough electric potential, a discharge across the gap and through the bath gas between the interfaces can occur. The potential at which this occurs depends upon the dielectric properties of the bath gas. | 0 | Theoretical and Fundamental Chemistry |
Oxaloacetic acid undergoes successive deprotonations to give the dianion:
:HOCC(O)CHCOH OCC(O)CHCOH + H, pK = 2.22
:OCC(O)CHCOH OCC(O)CHCO + H, pK = 3.89
At high pH, the enolizable proton is ionized:
:OCC(O)CHCO OCC(O)CHCO + H, pK = 13.03
The enol forms of oxaloacetic acid are particularly stable. Keto-enol tautomerization is catalyzed by the enzyme oxaloacetate tautomerase. trans-Enol-oxaloacetate also appears when tartrate is the substrate for fumarase. | 1 | Applied and Interdisciplinary Chemistry |
Zeldovich mechanism is a chemical mechanism that describes the oxidation of nitrogen and NO formation, first proposed by the Russian physicist Yakov Borisovich Zeldovich in 1946. The reaction mechanisms read as
where and are the reaction rate constants in Arrhenius law. The overall global reaction is given by
The overall reaction rate is mostly governed by the first reaction (i.e., rate-determining reaction), since the second reaction is much faster than the first reaction and occurs immediately following the first reaction. At fuel-rich conditions, due to lack of oxygen, reaction 2 becomes weak, hence, a third reaction is included in the mechanism, also known as extended Zel'dovich mechanism (with all three reactions),
Assuming the initial concentration of NO is low and the reverse reactions can therefore be ignored, the forward rate constants of the reactions are given by
where the pre-exponential factor is measured in units of cm, mol, s and K (these units are incorrect), temperature in kelvins, and the activation energy in cal/mol; R is the universal gas constant. | 0 | Theoretical and Fundamental Chemistry |
piRNAs represent the largest class of small non-coding RNA molecules expressed in animal cells, deriving from a large variety of sources, including repetitive DNA and transposons. However, the biogenesis of piRNAs is also the least well understood. piRNAs appear to act both at the post-transcriptional and chromatin levels. They are distinct from miRNA due to at least an increase in terms of size and complexity. Repeat associated small interfering RNA (rasiRNAs) are considered to be a subspecies of piRNA. | 1 | Applied and Interdisciplinary Chemistry |
Buccianti was the 2003 winner of the Felix Chayes Prize of the International Association for Mathematical Geosciences. | 0 | Theoretical and Fundamental Chemistry |
N-Nitrosamines, including the carcinogenic variety, arise from the reaction of nitrite sources with amino compounds, which can happen during the curing of meat. Typically, this reaction occurs when the nucleophilic nitrogen of a secondary amine attacks the nitrogen of the electrophilic nitrosonium ion:
:NO + 2 H → NO + HO
:RNH + NO → RN-NO + H
Formation of an N-nitrosamine:
The nitrosamine can then lose water through protonation to form diazonium cation, which is a very useful intermediate to form different compounds. | 0 | Theoretical and Fundamental Chemistry |
The gastrointestinal tract is lined with epithelial cells. Drugs must pass through or permeate these cells to be absorbed into the bloodstream. Cell membranes may act as barriers to some drugs. They are essentially lipid bilayers which form semipermeable membranes. Pure lipid bilayers are generally permeable only to small, uncharged solutes. Hence, whether or not a molecule is ionized will affect its absorption, since ionic molecules are charged. Solubility favors charged species, and permeability favors neutral species. Some molecules have special exchange proteins and channels to facilitate movement from the lumen into the circulation.
Ions cannot passively diffuse through the gastrointestinal tract because the epithelial cell membrane is made up of a phospholipid bilayer, comprising two layers of phospholipids in which the charged hydrophilic heads face outwards and the uncharged hydrophobic fatty acid chains are in the middle of the layer. The fatty acid chains repel ionized, charged molecules. This means that the ionized molecules cannot pass through the intestinal membrane and be absorbed.
The Henderson-Hasselbalch equation offers a way to determine the proportion of a substance that is ionized at a given pH. In the stomach, drugs that are weak acids (such as aspirin) will be present mainly in their non-ionic form, and weak bases will be in their ionic form. Since non-ionic species diffuse more readily through cell membranes, weak acids will have a higher absorption in the highly acidic stomach.
However, the reverse is true in the basic environment of the intestines—weak bases (such as caffeine) will diffuse more readily since they will be non-ionic.
This aspect of absorption has been targeted by medicinal chemists. For example, they may choose an analog that is more likely to be in a non-ionic form. Also, the chemists may develop prodrugs of a compound—these chemical variants may be more readily absorbed and then metabolized by the body into the active compound. However, changing the structure of a molecule is less predictable than altering dissolution properties, since changes in chemical structure may affect the pharmacodynamic properties of a drug.
The solubility and permeability of a drug candidate are important physicochemical properties the scientist wants to know as early as possible. | 1 | Applied and Interdisciplinary Chemistry |
Multicolumn countercurrent solvent gradient purification (MCSGP) is a form of chromatography that is used to separate or purify biomolecules from complex mixtures. It was developed at the Swiss Federal Institute of Technology Zürich by Aumann and Morbidelli. The process consists of two to six chromatographic columns which are connected to one another in such a way that as the mixture moves through the columns the compound is purified into several fractions. | 0 | Theoretical and Fundamental Chemistry |
Gestonorone caproate was studied in the treatment of prostate cancer in men at a dosage of 400 mg per week by intramuscular injection but, in contrast to the case of benign prostatic hyperplasia, was found to be ineffective.
SH-834 was a combination of 90 mg estradiol valerate and 300 mg gestonorone caproate for weekly intramuscular injection that was developed by Schering in the 1960s and 1970s. It was investigated clinically as a treatment for breast cancer and was found to be effective. However, its effectiveness was found to be no better than that of an estrogen alone, and the combination was ultimately never marketed.
Gestonorone caproate was studied by Schering for use as a progestogen-only injectable contraceptive across a dose range of 2.5 to 200 mg once every one or two months but was never marketed. There is very little clinical experience of gestonorone caproate for this indication.
Gestonorone caproate has been studied in the treatment of ovarian cancer (in combination with cyclophosphamide), menstrual cycle-related mouth ulcers, and as a component of menopausal hormone therapy. | 0 | Theoretical and Fundamental Chemistry |
Signaling action in neurons by sigma-2 receptors and their associated ligands results in modulation of action potential firing by regulation of calcium and potassium channels. They also are involved in synaptic vesicular release and modulation of dopamine, serotonin, and glutamate, with activation and increase of the dopaminergic, serotonergic, and noradrenergic activity of neurons. | 1 | Applied and Interdisciplinary Chemistry |
By NIGMS program mandate, Glue Grant consortia must contain core resources and bridging projects. The EFI consists of six scientific cores which provide bioinformatic, structural, computational, and data management expertise to facilitate functional predictions for enzymes of unknown function targeted by the EFI. At the beginning of the grant, these predictions were tested by five Bridging Projects representing the amidohydrolase, enolase, GST, HAD, and isoprenoid synthase enzyme superfamilies. Three Bridging Projects now remain. In addition, the Anaerobic Enzymology Pilot Project was added in 2014 to explore the Radical SAM superfamily and Glycyl Radical Enzyme superfamily. | 1 | Applied and Interdisciplinary Chemistry |
In the field of drug discovery, reverse pharmacology also known as target-based drug discovery (TDD), a hypothesis is first made that modulation of the activity of a specific protein target thought to be disease modifying will have beneficial therapeutic effects. Screening of chemical libraries of small molecules is then used to identify compounds that bind with high affinity to the target. The hits from these screens are then used as starting points for drug discovery. This method became popular after the sequencing of the human genome which allowed rapid cloning and synthesis of large quantities of purified proteins. This method is the most widely used in drug discovery today. Differently than the classical (forward) pharmacology, with the reverse pharmacology approach in vivo efficacy of identified active (lead) compounds is usually performed in the final drug discovery stages. | 1 | Applied and Interdisciplinary Chemistry |
In the field of condensed matter physics, microwave spectroscopy is used to detect dynamic phenomena of either charges or spins at GHz frequencies (corresponding to nanosecond time scales) and energy scales in the µeV regime. Matching to these energy scales, microwave spectroscopy on solids is often performed as a function of temperature (down to cryogenic regimes of a few K or even lower) and/or magnetic field (with fields up to several T).
Spectroscopy traditionally considers the frequency-dependent response of materials, and in the study of dielectrics microwave spectroscopy often covers a large frequency range. In contrast, for conductive samples as well as for magnetic resonance, experiments at a fixed frequency are common (using a highly sensitive microwave resonator), but frequency-dependent measurements are also possible. | 0 | Theoretical and Fundamental Chemistry |
Another major benefit of blue roofs are their ability to work alongside other rooftop systems such as solar panels (both solar thermal and pv), and HVAC mechanical equipment.
Some recreational blue roofs integrate rooftop waterplay areas that can also be used to irrigate a green roof, or to cool the roof of a building on hot days, in order to eliminate or at least reduce the HVAC load placed on mechanical refrigeration equipment.
Some blue roofs utilize stored water for beneficial on-site purposes cooling of solar panels and irrigation of a green roof. One example of a blue roof that provide ancillary services was the winning entry (First Place, 10,000 Euro prize) in the 2004 Coram Sustainable Design Award, by Steve Mann. | 1 | Applied and Interdisciplinary Chemistry |
The modified gene therapy strategy of antisense IGF-I RNA (NIH n˚ 1602) using antisense / triple helix anti-IGF-I approach was registered in 2002, by Wiley gene therapy clinical trial - n˚ 635 and 636. The approach has shown promising results in the treatment of six different malignant tumors: glioblastoma, cancers of liver, colon, prostate, uterus, and ovary (Collaborative NATO Science Programme on Gene Therapy USA, France, Poland n˚ LST 980517 conducted by J. Trojan) (Trojan et al., 2012). This anti-gene antisense/triple helix therapy has proven to be efficient, due to the mechanism stopping simultaneously IGF-I expression on translation and transcription levels, strengthening anti-tumor immune and apoptotic phenomena. | 1 | Applied and Interdisciplinary Chemistry |
If a gaseous emission sample is analyzed and found to contain water vapor and a pollutant concentration of say 40 ppmv, then 40 ppmv should be designated as the "wet basis" pollutant concentration. The following equation can be used to correct the measured "wet basis" concentration to a "dry basis" concentration:
As an example, a wet basis concentration of 40 ppmv in a gas having 10 volume percent water vapor would have a:
:C = 40 ÷ ( 1 - 0.10 ) = 44.4 ppmv. | 1 | Applied and Interdisciplinary Chemistry |
The finding of a potential sperm donor and motivating them to actually donate sperm is typically called recruitment. A sperm bank can recruit donors by advertising, often in colleges, in local newspapers, and also on the internet.
A donor must be a fit and healthy male, normally between 18 and 45 years of age, and willing to undergo frequent and rigorous testing. The donor must also be willing to donate their sperm so that it can be used to impregnate people who are unrelated to and unknown by them. Some sperm banks require two screenings and a laboratory screening before a donor is eligible. The donor must agree to relinquish all legal rights to all children which result from their donations. The donor must produce their sperm at the sperm bank thus enabling the identity of the donor, once proven, always to be ascertained, and also enabling fresh samples of sperm to be produced for immediate processing. Some sperm banks have been accused of heightism due to minimum height requirements. | 1 | Applied and Interdisciplinary Chemistry |
The SBSP concept also has a number of problems:
* The large cost of launching a satellite into space. For 6.5 kg/kW, the cost to place a power satellite in geosynchronous orbit (GEO) cannot exceed $200/kg if the power cost is to be competitive.
* Microwave optic requires gigawatt scale to compensate for Airy disk beam spreading. Typically a 1 km disk in geosynchronous orbit transmitting at 2.45 GHz spreads out to 10 km at Earth distance.
* Inability to constrain power transmission inside tiny beam angles. For example, a beam of 0.002 degrees (7.2 arc seconds) is required to stay within a one kilometer receiving antenna target from geostationary altitude. The most advanced directional wireless power transfer systems as of 2019 spread their half power beam width across at least 0.9 arc degrees.
* Inaccessibility: Maintenance of an earth-based solar panel is relatively simple, but construction and maintenance on a solar panel in space would typically be done telerobotically. In addition to cost, astronauts working in GEO are exposed to unacceptably high radiation dangers and risk and cost about one thousand times more than the same task done telerobotically.
* The space environment is hostile; PV panels (if used) suffer about eight times the degradation they would on Earth (except at orbits that are protected by the magnetosphere).
* Space debris is a major hazard to large objects in space, particularly for large structures such as SBSP systems in transit through the debris below 2000 km. Collision risk is much reduced in GEO since all the satellites are moving in the same direction at very close to the same speed.
* The broadcast frequency of the microwave downlink (if used) would require isolating the SBSP systems away from other satellites. GEO space is already well used and would require coordinating with the ITU-R.
* The large size and corresponding cost of the receiving station on the ground. The cost has been estimated at a billion dollars for 5 GW by SBSP researcher Keith Henson.
* Energy losses during several phases of conversion from photons to electrons to photons back to electrons.
* Waste heat disposal in space power systems is difficult to begin with, but becomes intractable when the entire spacecraft is designed to absorb as much solar radiation as possible. Traditional spacecraft thermal control systems such as radiative vanes may interfere with solar panel occlusion or power transmitters.
* Decommissioning costs: The cost of deorbiting the satellites at the end of their service life to prevent them from exacerbating the orbital space debris problem due to impacts with asteroidal, cometary, and planetary debris is likely to be significant. While the future cost of imparting Delta-V is difficult to estimate, the amount of Delta-V that must be imparted to transfer a satellite from GEO to GTO is 1472 m/s. If, upon reentry, the disintegrating satellite would release hazardous chemicals into the Earth's atmosphere, then the additional expenses of disassembling the satellite and deorbiting the environmentally hazardous components within a space vehicle with downmass capabilities must be factored into the decommissioning costs. | 0 | Theoretical and Fundamental Chemistry |
As describes, the vertices of the Laves graph can be defined by selecting one out of every eight points in the three-dimensional integer lattice, and forming their nearest neighbor graph. Specifically, one chooses the points
and all the other points formed by adding multiples of four to these coordinates. The edges of the Laves graph connect pairs of points whose Euclidean distance from each other is the square root of two, , as the points of each pair differ by one unit in two coordinates, and are the same in the third coordinate. The edges meet at 120° angles at each vertex, in a flat plane. All pairs of vertices that are non-adjacent are farther apart, at a distance of at least from each other. The edges of the resulting geometric graph are diagonals of a subset of the faces of the regular skew polyhedron with six square faces per vertex, so the Laves graph is embedded in this skew polyhedron.
It is possible to choose a larger set of one out of every four points of the integer lattice, so that the graph of distance- pairs of this larger set forms two mirror-image copies of the Laves graph, disconnected from each other, with all other pairs of points farther than apart. | 0 | Theoretical and Fundamental Chemistry |
The following tables give additional examples of commonly encountered polyatomic ions. Only a few representatives are given, as the number of polyatomic ions encountered in practice is very large. | 0 | Theoretical and Fundamental Chemistry |
In thermometric titrations, a constant addition rate of titrant equates to a constant amount of heat being given out or consumed, and hence a more or less constant temperature change up to the endpoint. In a titration, the titrant reacts with the analyte in the sample either exothermically or endothermically. The thermoprobe measures the temperature of the titrating solution. When all of the analyte in the sample has reacted with the titrant, the temperature of the solution will change, and the endpoint of the titration is revealed by an inflection in the temperature curve.
An appropriate aliquot of the sample is pipetted directly into the titration vessel, and isobutyl vinyl ether and toluene solvent are added. The solution is then titrated with trifluoro methane sulfonic acid (TFMSA) to a single thermometric endpoint. | 0 | Theoretical and Fundamental Chemistry |
* [http://www.chemicalland21.com/arokorhi/industrialchem/inorganic/HYPOPHOSPHOROUS%20ACID.htm ChemicalLand21 Listing] | 0 | Theoretical and Fundamental Chemistry |
The Minimum Information for Publication of Quantitative Real-Time PCR Experiments (MIQE) guidelines are a set of protocols for conducting and reporting quantitative real-time PCR experiments and data, as devised by Bustin et al. in 2009. They were devised after a paper was published in 2002 that claimed to detect measles virus in children with autism through the use of RT-qPCR, but the results proved to be completely unreproducible by other scientists. The authors themselves also did not try to reproduce them and the raw data was found to have a large amount of errors and basic mistakes in analysis. This incident prompted Stephen Bustin to create the MIQE guidelines to provide a baseline level of quality for qPCR data published in scientific literature. | 1 | Applied and Interdisciplinary Chemistry |
Sonoelectrochemistry is the application of ultrasound in electrochemistry. Like sonochemistry, sonoelectrochemistry was discovered in the early 20th century. The effects of power ultrasound on electrochemical systems and important electrochemical parameters were originally demonstrated by Moriguchi and then by Schmid and Ehert when the researchers investigated the influence of ultrasound on concentration polarisation, metal passivation and the production of electrolytic gases in aqueous solutions. In the late 1950s, Kolb and Nyborg showed that the electrochemical solution (or electroanalyte) hydrodynamics in an electrochemical cell was greatly increased in the presence of ultrasound and described this phenomenon as acoustic streaming. In 1959, Penn et al. demonstrated that sonication had a great effect on the electrode surface activity and electroanalyte species concentration profile throughout the solution. In the early 1960s, the electrochemist Allen J. Bard showed in controlled potential coulometry experiments that ultrasound significantly enhances mass transport of electrochemical species from the bulk solution to the electroactive surface.
In the range of ultrasonic frequencies [20 kHz – 2 MHz], ultrasound has been applied to many electrochemical systems, processes and areas of electrochemistry (to name but a few: electroplating, electrodeposition, electropolymerisation, electrocoagulation, organic electrosynthesis, materials electrochemistry, environmental electrochemistry, electroanalytical chemistry, hydrogen energy and fuel cell technology) both in academia and industry, as this technology offers several benefits over traditional technologies. The advantages are as follows: significant thinning of the diffusion layer thickness (δ) at the electrode surface; increase in electrodeposit/electroplating thickness; increase in electrochemical rates, yields and efficiencies; increase in electrodeposit porosity and hardness; increase in gas removal from electrochemical solutions; increase in electrode cleanliness and hence electrode surface activation; lowering in electrode overpotentials (due to metal depassivation and gas bubble removal generated at the electrode surface induced by cavitation and acoustic streaming); and suppression in electrode fouling (depending on the ultrasonic frequency and power).
To date, over 3,500 publications inc. patents, technical, research and review articles have been written on the subject with the vast majority being published post-1990 after a review paper from Mason et al. entitled Sonoelectrochemistry highlighting the extraordinary effects of sonication on enhancing mass transport, aiding solution degassing, improving electrode surface cleaning, producing radical species (via sonolysis) and increasing electrochemical products and yields. | 0 | Theoretical and Fundamental Chemistry |
Dioxane is produced by the acid-catalysed dehydration of diethylene glycol, which in turn is obtained from the hydrolysis of ethylene oxide.
In 1985, the global production capacity for dioxane was between 11,000 and 14,000 tons. In 1990, the total U.S. production volume of dioxane was between 5,250 and 9,150 tons. | 0 | Theoretical and Fundamental Chemistry |
P2 receptor may refer to:
Nucleotides, if released into the extracellular environment, can lead to cell death or other harmful cellular consequences. To avoid cellular damage, nucleotides should be neutralized, which is accomplished by P2 receptors. Almost every cell type expresses P2 receptors. Purinergic signalling also has a pathophysiological role in several immune cells including calcium mobilization, actin polymerization, chemotaxis, the release of mediators, cell maturation, cytotoxicity, and cell death etc.
Depending on the nature of the receptor they are found to be of two types:
*P2Y receptors (metabotropic)
*P2X receptors (ionotropic)
P is for purinergic, P2 refers to ATP receptors, as opposed to P1 adenosine adenosine receptors. P2X receptors are ATP activated channels that allow the passage of ions across cell membranes. P2Y receptors are ATP activated G protein-coupled receptors (GPCRs) that initiate an intracellular chain of reactions.
Extracellular ATP and the related purine and pyrimidine nucleotides exert their functions via signalling through membrane-bound purinergic P2 receptors. These receptors are widely expressed throughout the body on various immune and nonimmune cells. P2X receptors are ionotropic receptors while P2Y are GPCR type receptors. P2X receptor family encompasses 7 genes. P2Y family has 8 receptors that can be divided into two sub-families depending upon the structural similarity. P2X receptors are activated with ATP while P2Y receptors are activated by diphosphates, triphosphates, purines, pyrimidines, etc. | 1 | Applied and Interdisciplinary Chemistry |
Animal studies have shown the benefit of targeted temperature management in traumatic central nervous system (CNS) injuries. Clinical trials have shown mixed results with regards to the optimal temperature and delay of cooling. Achieving therapeutic temperatures of is thought to prevent secondary neurological injuries after severe CNS trauma. A systematic review of randomised controlled trials in traumatic brain injury (TBI) suggests there is no evidence that hypothermia is beneficial. | 1 | Applied and Interdisciplinary Chemistry |
Porphyrin-based compounds are of interest as possible components of molecular electronics and photonics. Synthetic porphyrin dyes have been incorporated in prototype dye-sensitized solar cells. | 1 | Applied and Interdisciplinary Chemistry |
Periana's group was also able to convert methane into acetic acid using similar conditions to the Catalytica system. Palladium(II) salts were used in this process, and the products formed were a mixture of methanol and acetic acid, along with side products of carbon monoxide and possibly carbon dioxide due to over-oxidation. The mechanism of reaction involves another electrophilic activation of methane, and when carbon monoxide is incorporated, the acetic acid derivative is generated through its activation to an acyl intermediate ().
Another example of acetic acid synthesis was demonstrated by Pombeiro et al., which used vanadium-based complexes in trifluoroacetic acid with peroxodisulfate as the oxidant. The proposed mechanism involves a radical mechanism, where methane is the methyl source and trifluoroacetic acid is the carbonyl source. Minor side products were formed, including methyltrifluoroacetate and methylsulfate. | 0 | Theoretical and Fundamental Chemistry |
The 4 main classes of molecules in biochemistry (often called biomolecules) are carbohydrates, lipids, proteins, and nucleic acids. Many biological molecules are polymers: in this terminology, monomers are relatively small macromolecules that are linked together to create large macromolecules known as polymers. When monomers are linked together to synthesize a biological polymer, they undergo a process called dehydration synthesis. Different macromolecules can assemble in larger complexes, often needed for biological activity. | 1 | Applied and Interdisciplinary Chemistry |
Methylglyoxal (MGO) is the organic compound with the formula CHC(O)CHO. It is a reduced derivative of pyruvic acid. It is a reactive compound that is implicated in the biology of diabetes. Methylglyoxal is produced industrially by degradation of carbohydrates using overexpressed methylglyoxal synthase. | 1 | Applied and Interdisciplinary Chemistry |
Bioremediation utilizes microorganisms or in recent times, materials of biological origin, such as enzymes, biocomposites, biopolymers, or nanoparticles, to biochemically degrade contaminants into harmless substances, making it an environmentally friendly and cost-effective alternative; 3D bioprinting facilitates the fabrication of functional structures utilizing these materials that enhance bioremediation processes leading to a significant interest in the application of 3D bioprinted constructs in improving bioremediation. | 1 | Applied and Interdisciplinary Chemistry |
Calcineurin inhibitors such as tacrolimus are used to suppress the immune system in organ allotransplant recipients to prevent rejection of the transplanted tissue. | 1 | Applied and Interdisciplinary Chemistry |
Most carbon incorporated in organic and inorganic biological matter is formed at the sea surface where it can then start sinking to the ocean floor. The deep ocean gets most of its nutrients from the higher water column when they sink down in the form of marine snow. This is made up of dead or dying animals and microbes, fecal matter, sand and other inorganic material. A single phytoplankton cell has a sinking rate around one metre per day. Given that the average depth of the ocean is about four kilometres, it can take over ten years for these cells to reach the ocean floor. However, through processes such as coagulation and expulsion in predator fecal pellets, these cells form aggregates. These aggregates, known as marine snow, have sinking rates orders of magnitude greater than individual cells and complete their journey to the deep in a matter of days.
In the diagram on the right, phytoplankton fix CO in the euphotic zone using solar energy and produce particulate organic carbon (POC). POC formed in the euphotic zone is processed by microbes, zooplankton and their consumers into organic aggregates (marine snow), which is thereafter exported to the mesopelagic (200–1000 m depth) and bathypelagic zones by sinking and vertical migration by zooplankton and fish. Export flux is defined as the sedimentation out of the surface layer (at approximately 100 m depth) and sequestration flux is the sedimentation out of the mesopelagic zone (at approximately 1000 m depth). A portion of the POC is respired back to CO in the oceanic water column at depth, mostly by heterotrophic microbes and zooplankton, thus maintaining a vertical gradient in concentration of dissolved inorganic carbon (DIC). This deep-ocean DIC returns to the atmosphere on millennial timescales through thermohaline circulation. Between 1% and 40% of the primary production is exported out of the euphotic zone, which attenuates exponentially towards the base of the mesopelagic zone and only about 1% of the surface production reaches the sea floor.
Of the 50–60 Pg of carbon fixed annually, roughly 10% leaves the surface mixed layer of the oceans, while less than 0.5% of eventually reaches the sea floor. Most is retained in regenerated production in the euphotic zone and a significant portion is remineralized in midwater processes during particle sinking. The portion of carbon that leaves the surface mixed layer of the ocean is sometimes considered "sequestered", and essentially removed from contact with the atmosphere for many centuries. However, work also finds that, in regions such as the Southern Ocean, much of this carbon can quickly (within decades) come back into contact with the atmosphere.
Budget calculations of the biological carbon pump are based on the ratio between sedimentation (carbon export) and remineralization (release to the atmosphere). It has been estimated that sinking particles export up to 25% of the carbon captured by phytoplankton in the surface ocean to deeper water layers. About 20% of this export (5% of surface values) is buried in the ocean sediments mainly due to their mineral ballast. During the sinking process, these organic particles are hotspots of microbial activity and represent important loci for organic matter mineralization and nutrient redistribution in the water column. | 0 | Theoretical and Fundamental Chemistry |
Hapticity (represented by Greek letter η) refers to the number of contiguous atoms that comprise a donor site and attach to a metal center. The η-notation applies when multiple atoms are coordinated. For example, η is a ligand that coordinates through two contiguous atoms. Butadiene forms both η and η complexes depending on the number of carbon atoms that are bonded to the metal. | 0 | Theoretical and Fundamental Chemistry |
The work wind does on the ocean can be computed by
where is the chosen parameterization for the wind stress.
Thus, in resting ocean approximation, the work done on the ocean by the wind is
Furthermore, if the relative wind stress parameterization is used, the work done on the ocean is given by
Then, assuming is the same in both situations, the difference between work done by resting ocean wind stress and relative wind stress is given by
Analysing this expression, we first see that the term is always positive (since and all the other terms are positive). Next, for the term , we have:
* if then and so the overall sign is positive.
* if then and again, the overall sign is positive.
Therefore, it is always the case that , meaning the calculation of the work done is always larger when using the resting ocean wind stress. This overestimate is referred to in the literature as a "positive bias". Note that this may not be the case if the used in the calculation of is different from the used in the calculations of (See section: Ocean currents as output of ocean models). | 1 | Applied and Interdisciplinary Chemistry |
* corresponding academician of the Spanish Royal Academy of Sciences (1934)
* Hero of Socialist Labor (06/10/1945)
* four Orders of Lenin (05/07/1940; 06/10/1945; 02/05/1946; 02/05/1951)
* two PrOrders of the Red Banner of Labor (03/29/1941; 04/03/1944)
* USSR State Prize from the seizure of the chemicalization of the national economy of the USSR (1934)
* USSR State Prize of the first degree (1942) - for outstanding scientific works on organic chemistry, published in the collection of selected works of the author in 1941
* USSR State Prize of the second degree (1946) - for the development of a new method for obtaining aromatic hydrocarbons
* USSR State Prize of the first degree (1948)
* A. M. Butlerov Prize of the Russian Physical and Chemical Society (1924) | 0 | Theoretical and Fundamental Chemistry |
IL-26 is a newly discovered cytokine produced by memory T cells and monocytes. IL-26 assist with the process of human T cell transformation after their infections. | 1 | Applied and Interdisciplinary Chemistry |
Trioxidane (systematically named dihydrogen trioxide,), also called hydrogen trioxide is an inorganic compound with the chemical formula (can be written as or ). It is one of the unstable hydrogen polyoxides. In aqueous solutions, trioxidane decomposes to form water and singlet oxygen:
The reverse reaction, the addition of singlet oxygen to water, typically does not occur in part due to the scarcity of singlet oxygen. In biological systems, however, ozone is known to be generated from singlet oxygen, and the presumed mechanism is an antibody-catalyzed production of trioxidane from singlet oxygen. | 0 | Theoretical and Fundamental Chemistry |
Of some interest in organic synthesis, electropositive metals react with many organic halides in a metal-halogen exchange:
The resulting organometallic compound is susceptible to hydrolysis:
Heavily studied examples are found in organolithium chemistry and organomagnesium chemistry. Some illustrative cases follow.
Lithium-halogen exchange is essentially irrelevant to remediation, but the method is useful for fine chemical synthesis. Sodium metal has been used for dehalogenation process.
Removal of halogen atom from arene-halides in the presence of Grignard agent and water for the formation of new compound is known as Grignard degradation. Dehalogenation using Grignard reagents is a two steps hydrodehalogenation process. The reaction begins with the formation of alkyl/arene-magnesium-halogen compound, followed by addition of proton source to form dehalogenated product. Egorov and his co-workers have reported dehalogenation of benzyl halides using atomic magnesium in 3P state at 600 °C. Toluene and bi-benzyls were produced as the product of the reaction. Morrison and his co-workers also reported dehalogenation of organic halides by flash vacuum pyrolysis using magnesium. | 0 | Theoretical and Fundamental Chemistry |
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