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C12H15NO3 The molecular formula CHNO (molar mass : 221.25 g/mol) may refer to : | https://en.wikipedia.org/wiki?curid=23443743 |
UDPG may refer to: | https://en.wikipedia.org/wiki?curid=23445224 |
Gas combustion retort process The gas combustion retort process (also referred as gas-combustion retorting process) was an above-ground retorting technology for shale oil extraction. It was a predecessor of the Paraho and Petrosix processes, and modern directly heated oil shale retorting technologies in general. The gas combustion retort process was developed by the United States Bureau of Mines at the end of the 1940s. The first gas combustion retort, designed by Cameron Engineers, went into operation in 1949 and it was located in the United States Bureau of Mines' Oil Shale Experiment Station at Anvil Point in Rifle, Colorado. The Bureau of Mines tested this process in three retorts with capacity of 6, 10, and 25 ton of oil shale per day accordingly. The consortium of Mobil, Humble Oil, Continental Oil, Pan American Oil, Phillips Petroleum Company, and Sinclair Oil evaluated and improved this technology between 1964 and 1968. The gas combustion retort process is classified as an internal combustion technology. For the oil shale pyrolysis it uses a vertical vessel retort. Crushed raw oil shale is fed into the top of the retort, and it moves downward by gravity. When moving downward, oil shale is heated by the rising recycled gases, which cause decomposition of the rock. Recycled gases enter the retort from the bottom. Gases are heated on the lower part of retort by descended spent shale | https://en.wikipedia.org/wiki?curid=23446427 |
Gas combustion retort process On their way up, gases move through the combustion zone, where air and dilution gases are injected causing combustion of gases and carbonaceous residue of spent shale (char). The heat from combustion brings the temperature in the retorting zone above of the burning zone to the necessary level for retorting. The incoming raw oil shale cool oil vapors and gases, which then leave the top of the retort as a mist. The main advantage of this process was that it does not require cooling water, which made it suitable for using in the semi-arid regions. | https://en.wikipedia.org/wiki?curid=23446427 |
Tantalate is an tantalum-containing anion or a salt of such an anion. A commercially important example is heptafluorotantalate (TaF) and its potassium salt (KTaF). Many oxides of tantalum are called tantalates. They are viewed as derivatives of "tantalic acid", hypothetic compounds with the formulas TaO·nHO or HTaO). Examples of such tantalates are lithium tantalate (LiTaO), lutetium tantalate (LuTaO) and lead scandium tantalate (PST or Pb(ScTa)O. Polyoxometallates containing tantalum provide examples of discrete tantalum oxides that exist in solution. | https://en.wikipedia.org/wiki?curid=23449302 |
C7H15NO3 The molecular formula CHNO may refer to: | https://en.wikipedia.org/wiki?curid=23453330 |
C10H14O The molecular formula CHO (molar mass: 150.22 g/mol, exact mass: 150.104465 u) can refer to: | https://en.wikipedia.org/wiki?curid=23453338 |
C2HCl3O The molecular formula CHClO may refer to: | https://en.wikipedia.org/wiki?curid=23453612 |
C2H3ClO2 The molecular formula CHClO may refer to: | https://en.wikipedia.org/wiki?curid=23455097 |
Fluorescence in the life sciences Fluorescence is used in the life sciences generally as a non-destructive way of tracking or analysing biological molecules by means of fluorescence. Some proteins or small molecules in cells are naturally fluorescent, which is called intrinsic fluorescence or autofluorescence (such as NADH, tryptophan or endogenous chlorophyll, phycoerythrin or green fluorescent protein). Alternatively, specific or general proteins, nucleic acids, lipids or small molecules can be "labelled" with an extrinsic fluorophore, a fluorescent dye which can be a small molecule, protein or quantum dot. Several techniques exist to exploit additional properties of fluorophores, such as fluorescence resonance energy transfer, where the energy is passed non-radiatively to a particular neighbouring dye, allowing proximity or protein activation to be detected; another is the change in properties, such as intensity, of certain dyes depending on their environment allowing their use in structural studies. The principle behind fluorescence is that the fluorescent moiety contains electrons which can absorb a photon and briefly enter an excited state before either dispersing the energy non-radiatively or emitting it as a photon, but with a lower energy, i.e., at a longer wavelength (wavelength and energy are inversely proportional). The difference in the excitation and emission wavelengths is called the Stokes shift, and the time that an excited electron takes to emit the photon is called a lifetime | https://en.wikipedia.org/wiki?curid=23455526 |
Fluorescence in the life sciences The quantum yield is an indicator of the efficiency of the dye (it is the ratio of emitted photons per absorbed photon), and the extinction coefficient is the amount of light that can be absorbed by a fluorophore. Both the quantum yield and extinction coefficient are specific for each fluorophore and multiplied together calculates the brightness of the fluorescent molecule. Fluorophores can be attached to proteins via specific functional groups, such as or non-specificately (glutaraldehyde) or non-covalently ("e.g." via hydrophobicity, etc.). These fluorophores are either small molecules, protein or quantum dots. Organic fluorophores fluoresce thanks to delocalized electrons which can jump a band and stabilize the energy absorbed, hence most fluorophores are conjugated systems. Several families exits and their excitations range from the infrared to the ultraviolet. <br>Lanthanides (chelated) are uniquely fluorescent metals, which emit thanks to transitions involving 4"f" orbits, which are forbidden, hence they have very low absorption coefficients and slow emissions, requiring exitation through fluorescent organic chelators ("e.g." dipicolinate-based Terbium (III) chelators ). <br>A third class of small molecule fluorophore is that of the transition metal-ligand complexes, which display molecular fluorescence from a metal-to-ligand charge transfer state which is partially forbidden, these are generally complexes of Ruthenium, Rhenium or Osmium. Quantum dots are fluorescent semiconductor nanoparticles | https://en.wikipedia.org/wiki?curid=23455526 |
Fluorescence in the life sciences Several fluorescent protein exist in nature, but the most important one as a research tool is Green Fluorescent Protein (GFP) from the jellyfish "Aequorea victoria", which spontaneously fluoresces upon folding via specific serine-tyrosine-glycine residues. The benefit that GFP and other fluorescent proteins have over organic dyes or quantum dots is that they can be expressed exogenously in cells alone or as a fusion protein, a protein that is created by ligating the fluorescent gene (e.g., GFP) to another gene and whose expression is driven by a housekeeping gene promoter or another specific promoter. This approach allows fluorescent proteins to be used as reporters for any number of biological events, such as sub-cellular localization and expression patterns. A variant of GFP is naturally found in corals, specifically the Anthozoa, and several mutants have been created to span the visible spectra and fluoresce longer and more stably. Other proteins are fluorescent but require a fluorophore cofactor, and hence can only be used "in vitro"; these are often found in plants and algae (phytofluors, phycobiliprotein such as allophycocyanin). Fluorescence, chemiluminescence and phosphorescence are 3 different types of luminescence properties, i.e. emission of light from a substance. Fluorescence is a property where light is absorbed and remitted within a few nanoseconds (approx | https://en.wikipedia.org/wiki?curid=23455526 |
Fluorescence in the life sciences 10ns) at a lower energy (=higher wavelength), while bioluminescence is biological chemiluminescence, a property where light is generated by a chemical reaction of an enzyme on a substrate. Phosphorescence is a property of materials to absorb light and emit the energy several milliseconds or more later (due to forbidden transitions to the ground state of a triplet state, while fluorescence occurs in exited singlet states). Until recently was not applicable to life science research due to the size of the inorganic particles. However the boundary between the fluorescence and phosphorescence is not clean cut as transition metal-ligand complexes, which combine a metal and several organic moieties, have long lifetimes, up to several microseconds (as they display mixed singlet-triplet states). Prior to its widespread use in the past three decades radioactivity was the most common label. The advantages of fluorescence over radioactive labels are as follows: Note: a channel is similar to "colour" but distinct, it is the pair of excitation and emission filters specific for a dye, e.g. agilent microarrays are dual channel, working on cy3 and cy5, these are colloquially referred to as green and red. Fluorescence is not necessarily more convenient to use because it requires specialized detection equipment of its own | https://en.wikipedia.org/wiki?curid=23455526 |
Fluorescence in the life sciences For non-quantitative or relative quantification applications it can be useful but it is poorly suited for making absolute measurement because of fluorescence quenching, whereas measuring radioactively labeled molecules is always direct and highly sensitive. Disadvantages of fluorophores include: The basic property of fluorescence are extensively used, such as a marker of labelled components in cells (fluorescence microscopy) or as an indicator in solution (Fluorescence spectroscopy), but other additional properties, not found with radioactivity, make it even more extensively used. FRET (Förster resonance energy transfer) is a property in which the energy of the excited electron of one fluorphore, called the donor, is passed on to a nearby acceptor dye, either a dark quencher or another fluorophore, which has an excitation spectrum which overlaps with the emission spectrum of the donor dye resulting in a reduced fluorescence. This can be used to Environment-sensitive dyes change their properties (intensity, half-life, and excitation and emission spectra) depending on the polarity (hydrophobicity and charge) of their environments. examples include: Indole, Cascade Yellow, prodan, Dansyl, Dapoxyl, NBD, PyMPO, Pyrene and diethylaminocumarin. This change is most pronounced when electron-donating and electron-withdrawing groups are placed at opposite ends of an aromatic ring system, as this results in a large change in dipole moment when excited | https://en.wikipedia.org/wiki?curid=23455526 |
Fluorescence in the life sciences When a fluorophore is excited, it generally has a larger dipole moment (μ) than in the ground state (μ). Absorption of a photon by a fluorophore takes a few picoseconds. Before this energy is released (emission: 1–10 ns), the solvent molecules surrounding the fluorophore reorient (10–100 ps) due to the change in polarity in the excited singlet state; this process is called solvent relaxation. As a result of this relaxation, the energy of the excited state of the fluorophore is lowered (longer wavelength), hence fluorophores that have a large change in dipole moment have larger stokes shift changes in different solvents. The difference between the energy levels can be roughly determined with the Lipper-Mataga equation. A hydrophobic dye is a dye which is insoluble in water, a property independent of solvatochromism. <br>Additionally, The term environment-sensitive in chemistry actually describes changes due to one of a variety of different environmental factors, such as pH or temperature, not just polarity; however, in biochemistry environment-sensitive fluorphore and solvatochromic fluorophore are used interchangeably: this convention is so widespread that suppliers describe them as environment-sensitive over solvatochromic. Fluorescent moieties emit photons several nanoseconds after absorption following an exponential decay curve, which differs between dyes and depends on the surrounding solvent. When the dye is attached to a macromolecules the decay curve becomes multiexponential | https://en.wikipedia.org/wiki?curid=23455526 |
Fluorescence in the life sciences Conjugated dyes generally have a lifetime between 1–10 ns, a small amount of longer lived exceptions exist, notably pyrene with a lifetime of 400ns in degassed solvents or 100ns in lipids and coronene with 200ns. On a different category of fluorphores are the fluorescent organometals (lanthanides and transition metal-ligand complexes) which have been previously described, which have much longer lifetimes due to the restricted states: lanthanides have lifetimes of 0.5 to 3 ms, while transition metal-ligand complexes have lifetimes of 10 ns to 10 µs. Note that fluorescent lifetime should not be confused with the photodestruction lifetime or the "shelf-life" of a dye. Multiphoton excitation is a way of focusing the viewing plane of the microscope by taking advantage of the phenomenon where two simultaneous low energy photons are absorbed by a fluorescent moiety which normally absorbs one photon with double their individual energy: say two NIR photons (800 nm) to excite a UV dye (400 nm). A perfectly immobile fluorescent moiety when exited with polarized light will emit light which is also polarized. However, if a molecule is moving, it will tend to "scramble" the polarization of the light by radiating at a different direction from the incident light. Also, many biological molecules have an intrinsic fluorescence that can sometimes be used without the need to attach a chemical tag | https://en.wikipedia.org/wiki?curid=23455526 |
Fluorescence in the life sciences Sometimes this intrinsic fluorescence changes when the molecule is in a specific environment, so the distribution or binding of the molecule can be measured. Bilirubin, for instance, is highly fluorescent when bound to a specific site on serum albumin. Zinc protoporphyrin, formed in developing red blood cells instead of hemoglobin when iron is unavailable or lead is present, has a bright fluorescence and can be used to detect these problems. The number of fluorescence applications in the biomedical, biological and related sciences continuously expands. Methods of analysis in these fields are also growing, often with nomenclature in the form of acronyms such as: FLIM, FLI, FLIP, CALI, FLIE, FRET, FRAP, FCS, PFRAP, smFRET, FIONA, FRIPS, SHREK, SHRIMP or TIRF. Most of these techniques rely on fluorescence microscopes, which use high intensity light sources, usually mercury or xenon lamps, LEDs, or lasers, to excite fluorescence in the samples under observation. Optical filters then separate excitation light from emitted fluorescence to be detected by eye or with a (CCD) camera or other light detector (e.g., photomultiplier tubes, spectrographs). Considerable research is underway to improve the capabilities of such microscopes, the fluorescent probes used, and the applications they are applied to. Of particular note are confocal microscopes, which use a pinhole to achieve optical sectioning, which affords a quantitative, 3D view of the sample. | https://en.wikipedia.org/wiki?curid=23455526 |
C7H5ClO2 The molecular formula CHClO may refer to: | https://en.wikipedia.org/wiki?curid=23455880 |
Kofler bench A or Kofler hot-stage microscope is a metal strip with a temperature gradient (range room temperature to 300°C). Any substance can be placed on a section of the strip revealing its thermal behaviour at the temperature at that point. This melting-point apparatus for use with a microscope was developed by the Austrian pharmacognosist Ludwig Kofler (30 November 1891 Dornbirn - 23 August 1951 Innsbruck) and his wife Adelheid Kofler. In 1936, the Koflers and Mayrhofer published their ""Mikroskopische Methoden in der Mikrochemie"" [Kofler, L., A. Kofler and Mayrhofer, A. (1936)], Kofler and Kofler published their ""Thermomikromethoden"" [Kofler L., and A. Kofler (1954)] in 1954. Kofler, his wife Adelheid, and their colleague, Maria Kuhnert-Brandstätter, investigated numerous organic molecules, and published some 250 papers describing their work. Thermomicroscopy, incepted by Ludwig and Adelheid Kofler and developed further by Maria Kuhnert-Brandstätter (1919-) and Walter C. McCrone is a technique for studying the phases of solid drug substances. | https://en.wikipedia.org/wiki?curid=23463958 |
Materials Knowledge Transfer Network The (Materials KTN) was a UK-based knowledge transfer organisation; as of 2016, it has been superseded by the Knowledge Transfer Network (KTN). The KTN is a network that brings together the views of those in business, design, research and technology organisations, trade associations, the financial market, academia and others across a wide variety of scientific fields. The provided a range of activities for members, such as events, webinars, online meeting tools, signposting to funding, assisting with applications for financial support, and helping to set up consortia for R&D projects, to enable the exchange of knowledge and the stimulation of business innovation in the UK, worked with training agencies to develop courses in materials, and helped to broker vocational and other training for people involved in materials. The Knowledge Transfer Network has continued with all of these functions. Membership of the KTN is free. The Materials KTN was funded by the Technology Strategy Board of the Department for Business, Innovation and Skills and run by the Institute of Materials, Minerals and Mining in London. It was one of a number of KTNs funded by the Technology Strategy Board. These separate KTNs have now been combined into one body, the Knowledge Transfer Network. | https://en.wikipedia.org/wiki?curid=23466159 |
Electron wake is the disturbance left after a high-energy charged particle passes through condensed matter or plasma. Ions passing through can introduce periodic oscillations in the crystal lattice or plasma wave with the characteristic frequency of the crystal or plasma frequency. Interactions of the field created by these oscillations with the charged particle field alternate from constructive interference to destructive interference, producing alternating waves of electric field and displacement. The frequency of the wake field is determined by the nature of the penetrated matter, and the period of the wake field is directly proportional to the speed of the incoming charged particle. The amplitude of the first wake wave is the most important, as it produces a braking force on the charged particle, eventually slowing it down. Wake fields also can capture and guide lightweight ions or positrons in the direction perpendicular to the wake. The larger the speed of the original charged particle, the larger the angle between the initial particle's velocity and the captured ion's velocity. | https://en.wikipedia.org/wiki?curid=23473596 |
Luttinger–Kohn model A flavor of the k·p perturbation theory used for calculating the structure of multiple, degenerate electronic bands in bulk and quantum well semiconductors. The method is a generalization of the single band k·p theory. In this model the influence of all other bands is taken into account by using Löwdin's perturbation method. All bands can be subdivided into two classes: The method concentrates on the bands in "Class A", and takes into account "Class B" bands perturbatively. We can write the perturbed solution formula_1 as a linear combination of the unperturbed eigenstates formula_2: Assuming the unperturbed eigenstates are orthonormalized, the eigenequation are: where From this expression we can write: where the first sum on the right-hand side is over the states in class A only, while the second sum is over the states on class B. Since we are interested in the coefficients formula_7 for "m" in class A, we may eliminate those in class B by an iteration procedure to obtain: Equivalently, for formula_10 (formula_11): and When the coefficients formula_10 belonging to Class A are determined so are formula_15. The Hamiltonian including the spin-orbit interaction can be written as: where formula_17 is the Pauli spin matrix vector. Substituting into the Schrödinger equation we obtain where and the perturbation Hamiltonian can be defined as The unperturbed Hamiltonian refers to the band-edge spin-orbit system (for "k"=0) | https://en.wikipedia.org/wiki?curid=23475491 |
Luttinger–Kohn model At the band edge, conduction band Bloch waves exhibit s-like symmetry, while valence band states are p-like (3-fold degenerate without spin). Let us denote these states as formula_21, and formula_22, formula_23 and formula_24 respectively. These Bloch functions can be pictured as periodic repetition of atomic orbitals, repeated at intervals corresponding to the lattice spacing. The Bloch function can be expanded in the following manner: where "j' " is in Class A and formula_26 is in Class B. The basis functions can be chosen to be Using Löwdin's method, only the following eigenvalue problem needs to be solved where The second term of formula_38 can be neglected compared to the similar term with p instead of k. Similarly to the single band case, we can write for formula_39 We now define the following parameters and the band structure parameters (or the Luttinger parameters) can be defined to be These parameters are very closely related to the effective masses of the holes in various valence bands. formula_48 and formula_49 describe the coupling of the formula_22, formula_23 and formula_24 states to the other states. The third parameter formula_53 relates to the anisotropy of the energy band structure around the formula_54 point when formula_55. The Luttinger-Kohn Hamiltonian formula_56 can be written explicitly as a 8X8 matrix (taking into account 8 bands - 2 conduction, 2 heavy-holes, 2 light-holes and 2 split-off) | https://en.wikipedia.org/wiki?curid=23475491 |
Gulf War syndrome or Gulf War illness is a chronic and multi-symptomatic disorder affecting returning military veterans of the 1990–1991 Persian Gulf War. A wide range of acute and chronic symptoms have been linked to it, including fatigue, muscle pain, cognitive problems, insomnia, rashes and diarrhea. Approximately 250,000 of the 697,000 U.S. veterans who served in the 1991 Gulf War are afflicted with enduring chronic multi-symptom illness, a condition with serious consequences. From 1995 to 2005, the health of combat veterans worsened in comparison with nondeployed veterans, with the onset of more new chronic diseases, functional impairment, repeated clinic visits and hospitalizations, chronic fatigue syndrome-like illness, posttraumatic stress disorder, and greater persistence of adverse health incidents. Exposure to pesticides and pills containing pyridostigmine bromide (used as a pretreatment to protect against nerve agent effects) has been found to be associated with the neurological effects seen in Gulf war syndrome. Other causes that have been investigated are sarin, cyclosarin, and emissions from oil well fire, but their relationship to the illness is not as clear. Studies have consistently indicated that is not the result of combat or other stressors and that Gulf War veterans have lower rates of posttraumatic stress disorder (PTSD) than veterans of other wars. According to a 2013 report by the Iraq and Afghanistan Veterans of America, veterans of the U.S | https://en.wikipedia.org/wiki?curid=23475629 |
Gulf War syndrome wars in Iraq and Afghanistan may also suffer from Gulf War syndrome, though later findings identified causes that would not have been present in those wars. According to an April 2010 U.S. Department of Veterans Affairs (VA) sponsored study conducted by the Institute of Medicine (IOM), part of the U.S. National Academy of Sciences, 250,000 of the 696,842 U.S. servicemen and women in the 1991 Gulf War continue to suffer from chronic multi-symptom illness, which the IOM now refers to as "Gulf War illness". The IOM found that it continued to affect these veterans nearly 20 years after the war. According to the IOM, "It is clear that a significant portion of the soldiers deployed to the Gulf War have experienced troubling constellations of symptoms that are difficult to categorize," said committee chair Stephen L. Hauser, professor and chair, department of neurology, University of California, San Francisco (UCSF). "Unfortunately, symptoms that cannot be easily quantified are sometimes incorrectly dismissed as insignificant and receive inadequate attention and funding by the medical and scientific establishment. Veterans who continue to suffer from these symptoms deserve the very best that modern science and medicine can offer to speed the development of effective treatments, cures, and—we hope—prevention. Our report suggests a path forward to accomplish this goal, and we believe that through a concerted national effort and rigorous scientific input, answers can be found | https://en.wikipedia.org/wiki?curid=23475629 |
Gulf War syndrome " Questions still exist regarding why certain veterans showed, and still show, medically unexplained symptoms while others did not, why symptoms are diverse in some and specific in others, and why combat exposure is not consistently linked to having or not having symptoms. The lack of data on veterans' pre-deployment and immediate post-deployment health status and lack of measurement and monitoring of the various substances to which veterans may have been exposed make it difficult — and in many cases impossible — to reconstruct what happened to service members during their deployments nearly 20 years after the fact, the committee noted. The report called for a substantial commitment to improving identification and treatment of multisymptom illness in Gulf War veterans focussing on continued monitoring of Gulf War veterans, improved medical care, examination of genetic differences between symptomatic and asymptomatic groups and studies of environment-gene interactions. A variety of signs and symptoms have been associated with GWI: Birth defects have been suggested as a consequence of Gulf War deployment. However, a 2006 review of several studies of international coalition veterans' children found no strong or consistent evidence of an increase in birth defects, finding a modest increase in birth defects that was within the range of the general population, in addition to being unable to exclude recall bias as an explanation for the results | https://en.wikipedia.org/wiki?curid=23475629 |
Gulf War syndrome A 2008 report stated that "it is difficult to draw firm conclusions related to birth defects and pregnancy outcomes in Gulf War veterans", observing that while there have been "significant, but modest, excess rates of birth defects in children of Gulf War veterans", the "overall rates are still within the normal range found in the general population". The same report called for more research on the issue. Gulf War veterans have been identified to have an increased risk of multiple sclerosis. A 2017 study by the U.S. Department of Veterans Affairs found that veterans possibly exposed to chemical warfare agents at Khamisiyah experienced different patterns of brain cancer mortality risk compared to the other groups, with veterans possibly exposed having a higher risk of brain cancer in the time period immediately following the Gulf War. The United States Congress mandated the U.S. Department of Veterans Affairs' contract with the National Academy of Sciences (NAS) to provide reports on Gulf War illnesses. Since 1998, the NAS's Institute of Medicine (IOM) has authored ten such reports. In addition to the many physical and psychological issues involving any war zone deployment, Gulf War veterans were exposed to a unique mix of hazards not previously experienced during wartime. These included pyridostigmine bromide pills (given to protect troops from the effects of nerve agents), depleted uranium munitions, and multiple simultaneous vaccinations including anthrax and botulinum toxin vaccines | https://en.wikipedia.org/wiki?curid=23475629 |
Gulf War syndrome The oil and smoke that spewed for months from hundreds of burning oil wells presented another exposure hazard not previously encountered in a war zone. Military personnel also had to cope with swarms of insects, requiring the widespread use of pesticides. High-powered microwaves were used to disrupt Iraqi communications, and though it is unknown whether this might have contributed to the syndrome, research has suggested that safety limits for electromagnetic radiation are too lenient. The Research Advisory Committee on Gulf War Veterans' Illnesses (RAC), a VA federal advisory committee mandated by Congress in legislation enacted in 1998, found that pre-2005 studies suggested the veterans' illnesses are neurological and apparently are linked to exposure to neurotoxins, such as the nerve gas sarin, the anti-nerve gas drug pyridostigmine bromide, and pesticides that affect the nervous system. The RAC concluded in 2004 that, "research studies conducted since the war have consistently indicated that psychiatric illness, combat experience or other deployment-related stressors do not explain Gulf War veterans illnesses in the large majority of ill veterans." The RAC concluded that "exposure to pesticides and/or to PB [pyridostigmine bromide nerve agent protective pills] are causally associated with GWI and the neurological dysfunction in GW veterans | https://en.wikipedia.org/wiki?curid=23475629 |
Gulf War syndrome Exposure to sarin and cyclosarin and to oil well fire emissions are also associated with neurologically based health effects, though their contribution to development of the disorder known as GWI is less clear. Gene-environment interactions are likely to have contributed to development of GWI in deployed veterans. The health consequences of chemical exposures in the GW and other conflicts have been called “toxic wounds” by veterans. This type of injury requires further study and concentrated treatment research efforts that may also benefit other occupational groups with similar exposure-related illnesses." Depleted uranium (DU) was widely used in tank kinetic energy penetrator and autocannon rounds for the first time ever during the Gulf War and has been suggested as a possible cause of Gulf War syndrome. A 2008 review by the U.S. Department of Veterans Affairs found no association between DU exposure and multisymptom illness, concluding that "exposure to DU munitions is not likely a primary cause of Gulf War illness". However, there are suggestions that long-term exposure to high doses of DU may cause other health problems unrelated to GWI. More recent medical literature reviews disagree, stating for example that, "the number of Gulf War veterans who developed the following exposure to high quantities of DU, has risen to about one-third of the 800,000 U.S. forces deployed," with 25,000 of those having suffered premature death | https://en.wikipedia.org/wiki?curid=23475629 |
Gulf War syndrome Since 2011, US combat veterans may claim disability compensation for health problems related to exposure to depleted uranium. The Veterans Administration decides these claims on a case-by-case basis. The US military issued pyridostigmine bromide (PB) pills to protect against exposure to nerve gas agents such as sarin and soman. PB was used as a prophylactic against nerve agents; it is not a vaccine. Taken before exposure to nerve agents, PB was thought to increase the efficiency of nerve agent antidotes. PB had been used since 1955 for patients suffering from myasthenia gravis with doses up to 1,500 mg a day, far in excess of the 90 mg given to soldiers, and was considered safe by the FDA at either level for indefinite use and its use to pre-treat nerve agent exposure had recently been approved. Given both the large body of epidemiological data on myasthenia gravis patients and follow-up studies done on veterans it was concluded that while it was unlikely that health effects reported today by Gulf War veterans are the result of exposure solely to PB, use of PB was causally associated with illness. However, a later review by the Institute of Medicine concluded that the evidence was not strong enough to establish a causal relationship. Organophosphate-induced delayed neuropathy (OPIDN, aka organophosphate-induced delayed polyneuropathy) may contribute to the unexplained illnesses of the Gulf War veterans | https://en.wikipedia.org/wiki?curid=23475629 |
Gulf War syndrome The use of organophosphate pesticides and insect repellents during the first Gulf War is credited with keeping rates of pest-borne diseases low. Pesticide use is one of only two exposures consistently identified by Gulf War epidemiologic studies to be significantly associated with Gulf War illness. Multisymptom illness profiles similar to Gulf War illness have been associated with low-level pesticide exposures in other human populations. In addition, Gulf War studies have identified dose-response effects, indicating that greater pesticide use is more strongly associated with Gulf War illness than more limited use. Pesticide use during the Gulf War has also been associated with neurocognitive deficits and neuroendocrine alterations in Gulf War veterans in clinical studies conducted following the end of the war. The 2008 report concluded that "all available sources of evidence combine to support a consistent and compelling case that pesticide use during the Gulf War is causally associated with Gulf War illness." Many of the symptoms of Gulf War illness are similar to the symptoms of organophosphate, mustard gas, and nerve gas poisoning. Gulf War veterans were exposed to a number of sources of these compounds, including nerve gas and pesticides. Chemical detection units from Czechoslovakia, France, and Britain confirmed chemical agents. French detection units detected chemical agents. Both Czech and French forces reported detections immediately to U.S. forces. U.S | https://en.wikipedia.org/wiki?curid=23475629 |
Gulf War syndrome forces detected, confirmed, and reported chemical agents; and U.S. soldiers were awarded medals for detecting chemical agents. The Riegle Report said that chemical alarms went off 18,000 times during the Gulf War. After the air war started on January 16, 1991, coalition forces were chronically exposed to low but nonlethal levels of chemical and biological agents released primarily by direct Iraqi attack via missiles, rockets, artillery, or aircraft munitions and by fallout from allied bombings of Iraqi chemical warfare munitions facilities. In 1997, the US Government released an unclassified report that stated: Over 125,000 U.S. troops and 9,000 U.K. troops were exposed to nerve gas and mustard gas when the Iraqi depot in Khamisiyah was destroyed. Recent studies have confirmed earlier suspicions that exposure to sarin, in combination with other contaminants such as pesticides and PB were related to reports of veteran illness. Estimates range from 100,000 to 300,000 individuals exposed to nerve agents. While low-level exposure to nerve agents has been suggested as the cause of GWI, the 2008 report by the U.S. Department of Veterans Affairs (VA) Research Advisory Committee on Gulf War illnesses (RAC) stated that "evidence is inconsistent or limited in important ways | https://en.wikipedia.org/wiki?curid=23475629 |
Gulf War syndrome " The VA's 2014 RAC report concluded that, "exposure to the nerve gas agents sarin/cyclosarin has been linked in two more studies to changes in structural magnetic resonance imaging findings that are associated with cognitive decrements, further supporting the conclusion from evidence reviewed in the 2008 report that exposure to these agents is etiologically important to the central nervous system dysfunction that occurs in some subsets of Gulf War veterans." According to the VA's 2008 RAC report, "For several Gulf War exposures, an association with Gulf War illness cannot be ruled out. These include low-level exposure to nerve agents, close proximity to oil well fires, receipt of multiple vaccines, and effects of combinations of Gulf War exposures." However, several potential causes of GWI were deemed, "not likely to have caused Gulf War illness for the majority of ill veterans," including "depleted uranium, anthrax vaccine, fuels, solvents, sand and particulates, infectious diseases, and chemical agent resistant coating (CARC)," for which "there is little evidence supporting an association with Gulf War illness or a major role is unlikely based on what is known about exposure patterns during the Gulf War and more recent deployments." The VA's 2014 RAC report reinforced its 2008 report findings: "The research reviewed in this report supports and reinforces the conclusion in the 2008 RACGWVI report that exposures to pesticides and pyridostigmine bromide are causally associated with Gulf War illness | https://en.wikipedia.org/wiki?curid=23475629 |
Gulf War syndrome Evidence also continues to demonstrate that Gulf War illness is not the result of psychological stressors during the war." It also found additional evidence since the 2008 report for the role of sarin in GWI, but inadequate evidence regarding exposures to oil well fires, vaccines, and depleted uranium to make new conclusions about them. During the war, many oil wells were set on fire in Kuwait by the retreating Iraqi army, and the smoke from those fires was inhaled by large numbers of soldiers, many of whom suffered acute pulmonary and other chronic effects, including asthma and bronchitis. However, firefighters who were assigned to the oil well fires and encountered the smoke, but who did not take part in combat, have not had GWI symptoms. The 2008 RAC report states that "evidence [linking oil well fires to GWI] is inconsistent or limited in important ways." Iraq had loaded anthrax, botulinum toxin, and aflatoxin into missiles and artillery shells in preparing for the Gulf War and these munitions were deployed to four locations in Iraq. During Operation Desert Storm, 41% of U.S. combat soldiers and 75% of UK combat soldiers were vaccinated against anthrax. Reactions included local skin irritation, some lasting for weeks or months. While the Food and Drug Administration (FDA) approved the vaccine, it never went through large-scale clinical trials | https://en.wikipedia.org/wiki?curid=23475629 |
Gulf War syndrome While recent studies have demonstrated the vaccine is highly reactogenic, and causes motor neuron death in mice, there is no clear evidence or epidemiological studies on Gulf War veterans linking the vaccine to Gulf War illness. Combining this with the lack of symptoms from current deployments of individuals who have received the vaccine led the Committee on Gulf War Veterans' Illnesses to conclude that the vaccine is not a likely cause of Gulf War illness for most ill veterans. However, the committee report does point out that veterans who received a larger number of various vaccines in advance of deployment have shown higher rates of persistent symptoms since the war. Research studies conducted since the war have consistently indicated that psychiatric illness, combat experience or other deployment-related stressors do not explain Gulf War veterans illnesses in the large majority of ill veterans, according to a U.S. Department of Veterans Affairs (VA) review committee. An April 2010 Institute of Medicine review found, "the excess of unexplained medical symptoms reported by deployed [1991] Gulf war veterans cannot be reliably ascribed to any known psychiatric disorder", although they also concluded that "the constellation of unexplained symptoms associated with the Gulf War illness complex could result from interplay between both biological and psychological factors | https://en.wikipedia.org/wiki?curid=23475629 |
Gulf War syndrome " The 2008 VA report on "Gulf War illness and the Health of Gulf War Veterans" suggested a possible link between GWI and chronic, nonspecific inflammation of the central nervous system that cause pain, fatigue and memory issues, possibly due to pathologically persistent increases in cytokines and suggested further research be conducted on this issue. Clinical diagnosis of Gulf War illness has been complicated by multiple case definitions. In 2014, the National Academy of Sciences Institute of Medicine (IOM)—contracted by the U.S. Department of Veterans Affairs for the task—released a report concluding that the creation of a new case definition for chronic multisymptom illness in Gulf War veterans was not possible because of insufficient evidence in published studies regarding its onset, duration, severity, frequency of symptoms, exclusionary criteria, and laboratory findings. Instead, the report recommended the use of two case definitions, the "Kansas" definition and the "Centers for Disease Control and Prevention (CDC)" definition, noting: "There is a set of symptoms (fatigue, pain, neurocognitive) that are reported in all the studies that have been reviewed. The CDC definition captures those three symptoms; the Kansas definition also captures them, but it also includes the symptoms reported most frequently by Gulf War veterans | https://en.wikipedia.org/wiki?curid=23475629 |
Gulf War syndrome " The Kansas case definition is more specific and may be more applicable for research settings, while the CDC case definition is more broad and may be more applicable for clinical settings. Medical ailments associated with service in the 1990–1991 Gulf War have been recognized by both the U.S. Department of Defense and the U.S. Department of Veterans Affairs. Before 1998, the terms "Gulf War syndrome, Gulf War veterans' illness, unexplained illness", and "undiagnosed illness" were used interchangeably to describe chronic unexplained symptoms in veterans of the 1991 Gulf War. The term "chronic multisymptom illness" (CMI) was first used following publication of a 1998 study describing chronic unexplained symptoms in Air Force veterans of the 1991 Gulf War. In a 2014 report contracted by the U.S. Department of Veterans Affairs, the National Academy of Sciences Institute of Medicine recommended the use the term "Gulf War illness" rather than "chronic multisymptom illness". Since that time, relevant publications by the National Academy of Science and the U.S. Department of Defense have used only the term "Gulf War illness" (GWI). The U.S. Department of Veterans Affairs (VA) confusingly still uses an array of both old and new terminology for "Gulf War illness". VA's specialty clinical evaluation War Related Illness and Injury Study Centers (WRIISCs) use the recommended term "Gulf War illness", as do VA's Office of Research and Development (VA-ORD) and many recent VA research publications | https://en.wikipedia.org/wiki?curid=23475629 |
Gulf War syndrome However, VA's Public Health website still uses "Gulf War veterans' medically unexplained illnesses", "medically unexplained illnesses", "chronic multi-symptom illness" (CMI), and "undiagnosed illnesses", but explains that VA doesn't use the term "Gulf War syndrome" because of varying symptoms. The Veterans Health Administration (VHA) originally classified individuals with related ailments believed to be connected to their service in the Persian Gulf a special non-ICD-9 code DX111, as well as ICD-9 code V65.5. In 1998, the State of Kansas Persian Gulf Veterans Health Initiative sponsored an epidemiological survey led by Dr. Lea Steele of deployment-related symptoms in 2,030 Gulf War veterans. The result was a "clinically based descriptive definition using correlated symptoms" in six symptom groups: fatigue and sleep problems, pain, neurologic and mood, gastrointestinal, respiratory symptoms, and skin (dermatologic) symptoms. To meet the "Kansas" case definition, a veteran of the 1990–91 Gulf War must have symptoms in at least three of the six symptom domains, which during the survey were scored based on severity ("severity"). Symptom onset must have developed during or after deploying to the 1990–91 Gulf War theatre of operations ("onset") and must have been present in the year before interview ("duration") | https://en.wikipedia.org/wiki?curid=23475629 |
Gulf War syndrome Participants were excluded if they had a diagnosis of or were being treated for any of several conditions that might otherwise explain their symptoms ("exclusionary criteria"), including cancer, diabetes, heart disease, chronic infectious disease, lupus, multiple sclerosis, stroke, or any serious psychiatric condition. Applying the Kansas case definition to the original Kansas study cohort resulted in a prevalence of Gulf War illness of 34.2% in Gulf War veterans and 8.3% in nondeployed Gulf War era veterans, or an excess rate of GWI of 26.3% in Gulf War veterans. Also in 1998, a study published by Dr. Keiji Fukuda under the auspices of the U.S. Centers for Disease Control and Prevention (CDC) examined chronic multisymptom illness through a cross-sectional survey of 3,675 ill and healthy U.S. Air Force veterans of the 1990–91 Gulf War, including from a Pennsylvania-based Air National Guard unit and three comparison Air Force units. The CDC case definition was derived from clinical data and statistical analyses. The result was a symptom-category approach to a case definition, with three symptom categories: fatigue, mood–cognition, and musculoskeletal. To meet the case definition, the veteran of the 1990–91 Gulf War must have symptoms in two of the three categories and have experienced the illness for six months or longer ("duration"). The original study also including a determination of severity of symptoms ("severity") | https://en.wikipedia.org/wiki?curid=23475629 |
Gulf War syndrome "Severe cases were identified if at least one symptom in each of the required categories was rated as severe. Of 1,155 participating Gulf War veterans, 6% had severe CMI, and 39% had mild to moderate CMI; of the 2,520 nondeployed era veterans Of 1,155 participating Gulf War veterans, 6% had severe CMI, and 39% had mild to moderate CMI; of the 2,520 nondeployed era veterans, 0.7% had severe and 14% had mild to moderate CMI." A 2013 report by the Institute of Medicine reviewed the peer-reviewed published medical literature for evidence regarding treatments for symptoms associated with "chronic multisymptom illness" (CMI) in 1990–91 Gulf War veterans, and in other chronic multisymptom conditions. For the studies the report reviewed that were specifically regarding CMI in 1990–91 Gulf War veterans ("Gulf War illness"), the report made the following conclusions: The report concluded: "On the basis of the evidence reviewed, the committee cannot recommend any specific therapy as a set treatment for [Gulf War] veterans who have CMI. The committee believes that a 'one-size-fits-all' approach is not effective for managing [Gulf War] veterans who have CMI and that individualized health care management plans are necessary." By contrast, the U.S. Department of Defense (DoD) noted in a May 2018 publication that the primary focus of its Gulf War illness Research Program (GWIRP) "has been to fund research studies to identify treatment targets and test interventional approaches to alleviate symptoms | https://en.wikipedia.org/wiki?curid=23475629 |
Gulf War syndrome While most of these studies remain in progress, several have already shown varying levels of promise as GWI treatments." According to the May 2018 DoD publication: Published Results on Treatments "The earliest federally funded multi-center clinical trials were VA- and DoD-funded trials that focused on antibiotic treatment (doxycycline) (Donta, 2004) and cognitive behavioral therapy with exercise (Donta, 2003). Neither intervention provided long-lasting improvement for a substantial number of Veterans." "Preliminary analysis from a placebo-controlled trial showed that 100 mg of Coenzyme Q10 (known as CoQ10 or Ubiquinone) significantly improved general self-reported health and physical functioning, including among 20 symptoms, each of which was present in at least half of the study participants, with the exception of sleep. These improvements included reducing commonly reported symptoms of fatigue, dysphoric mood, and pain (Golomb, 2014). These results are currently being expanded in a GWIRP-funded trial of a "mitochondrial cocktail" for GWI of CoQ10 plus a number of nutrients chosen to support cellular energy production and defend against oxidative stress. The treatment is also being investigated in a larger, VA- sponsored Phase III trial of Ubiquinol, the reduced form of CoQ10 | https://en.wikipedia.org/wiki?curid=23475629 |
Gulf War syndrome " "In a randomized, sham-controlled VA-funded trial of a nasal CPAP mask (Amin, 2011-b), symptomatic GW Veterans with sleep-disordered breathing receiving the CPAP therapy showed significant improvements in fatigue scores, cognitive function, sleep quality, and measures of physical and mental health (Amin, 2011a)." "Preliminary data from a GWIRP-funded acupuncture treatment study showed that Veterans reported significant reductions in pain and both primary and secondary health complaints, with results being more positive in the bi-weekly versus weekly treatment group (Conboy, 2012). Current studies funded by the GWIRP and the VA are also investigating yoga as a treatment for GWI." "An amino acid supplement containing L-carnosine was found to reduce irritable bowel syndrome-associated diarrhea in a randomized, controlled GWIRP-funded trial in GW Veterans (Baraniuk, 2013). Veterans receiving L-carnosine showed a significant improvement in performance in a cognitive task, but no improvement in fatigue, pain, hyperalgesia, or activity levels." "Results from a 26 week GWIRP-funded trial comparing standard care to nasal irrigation with either saline or a xylitol solution revealed that both irrigation protocols reduced GWI respiratory (chronic rhinosinusitis) and fatigue symptoms (Hayer, 2015) | https://en.wikipedia.org/wiki?curid=23475629 |
Gulf War syndrome " "Administration of the glucocorticoid receptor antagonist mifepristone to GW Veterans in a GWIRP-funded randomized trial resulted in an improvement in verbal learning, but no improvement in self-reported physical health or other self-reported measures of mental health (Golier, 2016)."Ongoing Intervention Studies "The GWIRP is currently funding many early-phase clinical trials aimed at GWI. Interventions include direct electrical nerve stimulation, repurposing FDA-approved pharmaceuticals, and dietary protocols and/or nutraceuticals. Both ongoing and closed GWIRP-supported clinical treatment trials and pilot studies can be found at <nowiki>http://cdmrp.army.mil/gwirp/resources/cinterventions.shtml</nowiki>." "A Clinical Consortium Award was offered [in FY2017] to support a group of institutions, coordinated through an Operations Center that will conceive, design, develop, and conduct collaborative Phase I and II clinical evaluations of promising therapeutic agents for the management or treatment of GWI. These mechanisms were designed to build on the achievements of the previously established consortia and to further promote collaboration and resource sharing." The U.S Congress has made significant and continuing investment in DoD's Gulf War illness treatment research, with $129 million appropriated for the GWIRP between federal fiscal years (FY) 2006 and 2016. The funding has risen from $5 million in FY2006, to $20 million each year from FY2013 through FY2017, and to $21 million for FY2018 | https://en.wikipedia.org/wiki?curid=23475629 |
Gulf War syndrome According to the May 2018 DoD publication cited above, "Research suggests that the GWI symptomology experienced by Veterans has not improved over the last 25 years, with few experiencing improvement or recovery ... . Many [Gulf War] Veterans will soon begin to experience the common co-morbidities associated with aging. The effect that aging will have on this unique and vulnerable population remains a matter of significant concern, and population-based research to obtain a better understanding of mortality, morbidity, and symptomology over time is needed." The 2008 and 2014 VA (RAC) reports and the 2010 IOM report found that the chronic multisymptom illness in Gulf War veterans—Gulf War illness—is more prevalent in Gulf War veterans than their non-deployed counterparts or veterans of previous conflicts. While a 2009 study found the pattern of comorbidities similar for actively deployed and nondeployed Australian military personnel, the large body of U.S. research reviewed in the VA and IOM reports showed the opposite in U.S. troops. The VA's 2014 RAC report found Gulf War illness in "an excess of 26–32 percent of Gulf War veterans compared to nondeployed era veterans" in pre-2008 studies, and "an overall multisymptom illness prevalence of 37 percent in Gulf War veterans and an excess prevalence of 25 percent" in a later, larger VA study. According to a May 2018 report by the U.S | https://en.wikipedia.org/wiki?curid=23475629 |
Gulf War syndrome Department of Defense, "GWI is estimated to have affected 175,000 to 250,000 of the nearly 700,000 troops deployed to the 1990–1991 GW theater of operations. Twenty-seven of the 28 Coalition members participating in the GW conflict have reported GWI in their troops. Epidemiologic studies indicate that rates of GWI vary in different subgroups of GW Veterans. GWI affects Veterans who served in the U.S. Army and Marines Corps at higher rates than those who served in the Navy and Air Force, and U.S. enlisted personnel are affected more than officers. Studies also indicate that GWI rates differ according to where Veterans were located during deployment, with the highest rates among troops who served in forward areas." Epidemiologic studies have looked at many suspected causal factors for Gulf War illness as seen in veteran populations. Below is a summary of epidemiologic studies of veterans displaying multisymptom illness and their exposure to suspect conditions from the 2008 U.S. Department of Veterans Affairs report. A fuller understanding of immune function in ill Gulf War veterans is needed, particularly in veteran subgroups with different clinical characteristics and exposure histories. It is also important to determine the extent to which identified immune perturbations may be associated with altered neurological and endocrine processes that are associated with immune regulation. Very limited cancer data have been reported for U.S | https://en.wikipedia.org/wiki?curid=23475629 |
Gulf War syndrome Gulf War veterans in general, and no published research on cases occurring after 1999. Because of the extended latency periods associated with most cancers, it is important that cancer information is brought up to date and that cancer rates be assessed in Gulf War veterans on an ongoing basis. In addition, cancer rates should be evaluated in relation to identifiable exposure and location subgroups. An early argument in the years following the Gulf War was that similar syndromes have been seen as an after effect of other conflicts — for example, "shell shock" after World War I, and post-traumatic stress disorder (PTSD) after the Vietnam War. Cited as evidence for this argument was a review of the medical records of 15,000 American Civil War soldiers showing that "those who lost at least 5% of their company had a 51% increased risk of later development of cardiac, gastrointestinal, or nervous disease." Early Gulf War research also failed to accurately account for the prevalence, duration, and health impact of Gulf War illness. For example, a November 1996 article in the "New England Journal of Medicine" found no difference in death rates, hospitalization rates, or self-reported symptoms between Persian Gulf veterans and non-Persian Gulf veterans. This article was a compilation of dozens of individual studies involving tens of thousands of veterans. The study did find a statistically significant elevation in the number of traffic accidents suffered by Gulf War veterans | https://en.wikipedia.org/wiki?curid=23475629 |
Gulf War syndrome An April 1998 article in "Emerging Infectious Diseases" similarly found no increased rate of hospitalization and better health on average for veterans of the Persian Gulf War in comparison to those who stayed home. In contrast to those early studies, in January 2006, a study led by Melvin Blanchard published in the "Journal of Epidemiology", part of the "National Health Survey of Gulf War-Era Veterans and Their Families", found that veterans deployed in the Persian Gulf War had nearly twice the prevalence of chronic multisymptom illness, a cluster of symptoms similar to a set of conditions often at that time called Gulf War Syndrome. On November 17, 2008, the Department of Veterans Affairs (VA) Research Advisory Committee on Gulf War Veterans' Illnesses (RAC), a Congressionally mandated federal advisory committee composed of VA-appointed clinicians, researchers, and representative Gulf War veterans, issued a major report announcing scientific findings, in part, that ""Gulf War illness is real"", that GWI is a distinct physical condition, and that it is not psychological in nature. The 454 page report reviewed 1,840 published studies to form its conclusions identifying the high prevalence of Gulf War illness, suggesting likely causes rooted in toxic exposures while ruling out combat stress as a cause, and opining that treatments likely could be found. It recommended that Congress increase funding for treatment-focused Gulf War illness research to at least $60 million per year | https://en.wikipedia.org/wiki?curid=23475629 |
Gulf War syndrome In March 2013, a hearing was held before the Subcommittee on Oversight and Investigations of the Committee on Veterans’ Affairs, U.S. House of Representatives, to determine not whether Gulf War illness exists, but rather how it is identified, diagnosed and treated, and how the tools put in place to aid these efforts have been used. By 2016, the National Academy of Sciences, Engineering, and Medicine (NASEM) concluded there was sufficient evidence of a positive association between deployment to the 1990–1991 Gulf War and Gulf War illness. Louis Jones Jr., the perpetrator of the 1995 murder of Tracie McBride, stated that the caused him to commit the crime and he sought clemency, hoping to avoid the death penalty given to him by a federal court. Jones was executed in 2003. On March 14, 2014, Representative Mike Coffman introduced the Gulf War Health Research Reform Act of 2014 (H.R. 4261; 113th Congress) into the United States House of Representatives, where it passed the House by unanimous consent but then died in Congress when the Senate failed to take action on it. The bill would have altered the relationship between the Research Advisory Committee on Gulf War Veterans' Illnesses (RAC) and the United States Department of Veterans Affairs (VA) under which the RAC is constituted | https://en.wikipedia.org/wiki?curid=23475629 |
Gulf War syndrome The bill would have made the RAC an independent organization within the VA, require that a majority of the RAC's members be appointed by Congress instead of the VA, and authorized the RAC to release its reports without needing prior approval from the VA Secretary. The RAC is responsible for investigating Gulf War illness, a chronic multisymptom disorder affecting returning military veterans of the 1990–91 Gulf War. In the year prior to the consideration of this bill, the VA and the RAC were at odds with one another. The VA replaced all but one of the members of the RAC, removed some of their supervisory tasks, tried to influence the board to decide that stress, rather than biology was the cause of Gulf War illness, and told the RAC that it could not publish reports without permission. The RAC was created after Congress decided that the VA's research into the issue was flawed, and focused on psychological causes, while mostly ignoring biological ones. The RAC was first authorized under the Veterans Programs Enhancement Act of 1998 (Section 104 of Public Law 105-368, enacted November 11, 1998, and now codified as 38 U.S.C. § 527 note). While the law directing its creation mandated that it be established not later than January 1, 1999, the RAC's first charter was not issued until January 23, 2002, by VA Secretary Anthony Principi. The RAC convened for its first meetings on April 11–12, 2002. | https://en.wikipedia.org/wiki?curid=23475629 |
Hydroxyacetylaminofluorene is a derivative of 2-acetylaminofluorene used as a biochemical tool in the study of carcinogenesis. | https://en.wikipedia.org/wiki?curid=23484834 |
Acetoxyacetylaminofluorene is a derivative of 2-acetylaminofluorene used as a biochemical tool in the study of carcinogenesis. It forms adducts with DNA by reacting with guanine at its C-8 position.; This results in breaks in one strand of the DNA. | https://en.wikipedia.org/wiki?curid=23484840 |
Mikamycin Mikamycins are a group of macrolide antibiotics. can refer to: | https://en.wikipedia.org/wiki?curid=23484883 |
Tenuazonic acid is a mycotoxin produced by "Alternaria" species. It is a powerful eukaryotic protein synthesis inhibitor. In 1991 was reported to inhibit skin tumor promotion in mice. | https://en.wikipedia.org/wiki?curid=23485206 |
Molecular Physics (journal) Molecular Physics is a peer-reviewed scientific journal covering research on the interface between chemistry and physics, in particular chemical physics and physical chemistry. It covers both theoretical and experimental molecular science, including electronic structure, molecular dynamics, spectroscopy, reaction kinetics, statistical mechanics, condensed matter and surface science. The journal was established in 1958 and is published by Taylor & Francis. According to the "Journal Citation Reports", the journal has a 2017 impact factor of 1.704. The current editor-in-chief is Professor George Jackson (Imperial College London). A reprint of the first editorial and a full list of editors since its establishment can be found in the issue celebrating 50 years of the journal. | https://en.wikipedia.org/wiki?curid=23486948 |
Transition metal dioxygen complex Dioxygen complexes are coordination compounds that contain O as a ligand. The study of these compounds is inspired by oxygen-carrying proteins such as myoglobin, hemoglobin, hemerythrin, and hemocyanin. Several transition metals form complexes with O, and many of these complexes form reversibly. The binding of O is the first step in many important phenomena, such as cellular respiration, corrosion, and industrial chemistry. The first synthetic oxygen complex was demonstrated in 1938 with cobalt(II) complex reversibly bound O. O binds to a single metal center either “end-on” ("η"-) or “side-on” ("η"-). The bonding and structures of these compounds are usually evaluated by single-crystal X-ray crystallography, focusing both on the overall geometry as well as the O–O distances, which reveals the bond order of the O ligand. O adducts derived from cobalt(II) and iron(II) complexes of porphyrin (and related anionic macrocyclic ligands) exhibit this bonding mode. Myoglobin and hemoglobin are famous examples, and many synthetic analogues have been described that behave similarly. Binding of O is usually described as proceeding by electron transfer from the metal(II) center to give superoxide () complexes of metal(III) centers. As shown by the mechanisms of cytochrome P450 and alpha-ketoglutarate-dependent hydroxylase, Fe-"η"-O bonding is conducive to formation of Fe(IV) oxo centers. O can bind to one metal of a bimetallic unit via the same modes discussed above for mononuclear complexes | https://en.wikipedia.org/wiki?curid=23491418 |
Transition metal dioxygen complex A well-known example is the active site of the protein hemerythrin, which features a diiron carboxylate that binds O at one Fe center. Dinuclear complexes can also cooperate in the binding, although the initial attack of O probably occurs at a single metal. "η"-bonding is the most common motif seen in coordination chemistry of dioxygen. Such complexes can be generated by treating low-valent metal complexes with oxygen. For example, Vaska's complex reversibly binds O (Ph = CH): The conversion is described as a 2 e redox process: Ir(I) converts to Ir(III) as dioxygen converts to peroxide. Since O has a triplet ground state and Vaska's complex is a singlet, the reaction is slower than when singlet oxygen is used. Complexes containing "η"-O ligands are fairly common, but most are generated using hydrogen peroxide, not O. Chromate ([CrO)]) can for example be converted to the tetraperoxide [Cr(O)]. The reaction of hydrogen peroxide with aqueous titanium(IV) gives a brightly colored peroxy complex that is a useful test for titanium as well as hydrogen peroxide. These binding modes include "μ"-"η","η"-, "μ"-"η","η"-, and "μ"-"η","η"-. Depending on the degree of electron-transfer from the dimetal unit, these O ligands can again be described as peroxo or superoxo. Hemocyanin is an O-carrier that utilizes a bridging O2 binding motif. It features a pair of copper centers. Salcomine, the cobalt(II) complex of salen ligand is the first synthetic O carrier. Solvated derivatives of the solid complex bind 0 | https://en.wikipedia.org/wiki?curid=23491418 |
Transition metal dioxygen complex 5 equivalent of O: Dioxygen complexes are the precursors to other families of oxygenic ligands. Metal oxo compounds arise from the cleavage of the O–O bond after complexation. Hydroperoxo complexes are generated in the course of the reduction of dioxygen by metals. The reduction of O by metal catalysts is a key half-reaction in fuel cells. Metal-catalyzed oxidations with O proceed via the intermediacy of dioxygen complexes, although the actual oxidants are often oxo derivatives. The reversible binding of O to metal complexes has been used as a means to purify oxygen from air, but cryogenic distillation of liquid air remains the dominant technology. | https://en.wikipedia.org/wiki?curid=23491418 |
Society for Mathematical Biology The (SMB) is an international association co-founded in 1972 in USA by Drs.George Karreman, Herbert Daniel Landahl and (initially chaired) by Anthony Bartholomay for the furtherance of joint scientific activities between Mathematics and Biology research communities. The society publishes the "Bulletin of Mathematical Biology", as well as the SMB annual newsletter. The emerged and grew from the earlier school of mathematical biophysics, initiated and supported by the Founder of Mathematical Biology, Nicolas Rashevsky. Thus, the roots of SMB go back to the publication in 1939 of the first international journal of mathematical biology, previously entitled "The Bulletin of Mathematical Biophysics"—which was founded by Nicolas Rashevsky, and which is currently published by SMB under the name of ""Bulletin of Mathematical Biology"". Professor Rashevsky also founded in 1969 the non-profit organization ""Mathematical Biology, Incorporated""—the precursor of SMB. Another notable member of the University of Chicago school of mathematical biology was Anatol Rapoport whose major interests were in developing basic concepts in the related area of mathematical sociology, who cofounded the Society for General Systems Research and became a president of the latter society in 1965. Herbert D | https://en.wikipedia.org/wiki?curid=23498666 |
Society for Mathematical Biology Landahl was initially also a member of Rashevsky's school of mathematical biology, and became the second president of SMB in the 1980s; both Herbert Landahl and Robert Rosen from Rashevsky's research group were focused on dynamical systems approaches to complex systems biology, with the latter researcher becoming in 1980 the president of the Society for General Systems Research. In addition to its research and news publications, the society supports education in: mathematical biology, mathematical biophysics, complex systems biology and theoretical biology through sponsorship of several topic-focused graduate and postdoctoral courses. To encourage and stimulate young researchers in this relatively new and rapidly developing field of mathematical biology, the society awards several prizes, as well as lists regularly new open international opportunities for researchers and students in this field. The society publishes the "Bulletin of Mathematical Biology", as well as the SMB annual newsletter. | https://en.wikipedia.org/wiki?curid=23498666 |
Carl Hudecek Carl J. Hudecek (born December 3, 1934) is an American, internationally known expert on sealing glasses, metal expansion and contraction, and metal oxidation processes for glass sealing. Hudecek holds or co-holds many U.S. and international patents in sealing glasses, television picture tube materials and processing, and sealing alloys. Hudecek was born in Toledo, Ohio. He is from Perrysburg, Ohio and graduated from the University of Toledo. Most of his working career was spent at Owens-Illinois Glass Company in Toledo, where he was chief physicist and laboratory manager. Hudecek was one of the U.S. pioneers in designing and installing turnkey manufacturing operations for sealing glasses in Russia and Germany. Through his consulting company, Perrysburg, Ohio-based Bridgecon Services, Hudecek consults in the area of sealing glasses. He has also taught courses on sealing and joining at Rutgers University and Missouri School of Mines. In addition, Hudecek is an expert at the game of contract bridge. He won the national American Contract Bridge League Life Master Open Pairs championship in 1966, partnered by Ray Zoller. Hudecek has been a member of the panel of experts for "The Bridge World" magazine for more than 45 years and has written many bridge articles and commentaries. | https://en.wikipedia.org/wiki?curid=23500359 |
Galanin-like peptide (GALP) is a neuropeptide present in humans and other mammals. It is a 60-amino acid polypeptide produced in the arcuate nucleus of the hypothalamus and the posterior pituitary gland. It is involved in the regulation of appetite and may also have other roles such as in inflammation, sex behavior, and stress. | https://en.wikipedia.org/wiki?curid=23508955 |
Nevada–Texas–Utah retort The process (also known as NTU, Dundas–Howes or Rexco process) was an above-ground shale oil extraction technology to produce shale oil, a type of synthetic crude oil. It heated oil shale in a sealed vessel (retort) causing its decomposition into shale oil, oil shale gas and spent residue. The process was developed in the 1920s and used for shale oil production in the United States and in Australia. The process was simple to operate; however, it was ceased from the operation because of a small capacity and labor extensiveness. The NTU retort was a successor of the 19th-century coal gasification retorts and it is considered as a predecessor of the gas combustion retort and the Paraho processes. It was invented and patented by Roy C. Dundas and Raymond T. Howes in 1923. The process was improved by David Davis and George Wightman Wallace, a consulting engineer of the NTU Company. In 1925, the NTU Company built a test plant at Sherman Cut near Casmalia, California. In 1925–1929, the process was tested by the United States Bureau of Mines in the Oil Shale Experiment Station at Anvil Point in Rifle, Colorado. Retorting was carried out from 17 January to 28 June 1927. The plant was dismantled when work was terminated in June 1929. One of the leading technologist involved in this stage was Lewis Cass Karrick, an inventor of the Karrick process. In 1946–1951, two pilot plants with nominal capacities of 40 tons of raw oil shale were located at the same location | https://en.wikipedia.org/wiki?curid=23515462 |
Nevada–Texas–Utah retort More than 12,000 barrels of shale oil was produced during this period. During the World War II, three NTU retorts were operated at Marangaroo, New South Wales, Australia. Almost 500,000 barrels of shale oil was produced by these retorts by retorting local torbanite. The NTU retort was a vertical downdraft retort, which used internal combustion to generate heat for an oil shale pyrolysis (chemical decomposition). The retort was designed as a steel cylinder, lined with fire bricks. At the top it was equipped with an air supply pipe and at the bottom it was equipped with an exhaust pipe. The batch of crushed oil shale was loaded from the top; after that the retort was sealed. To start the pyrolysis process the fuel gas was ignited at the top of retort, and air injection into the retort started. The supply of fuel gas stopped after the upper quarter of the oil shale batch started to burn. At the same time the air injection continued bringing temperature in the burning part to about . The heated gas caused a pyrolysis on the lower part of oil shale and produced shale oil and oil-shale gas are escaped from the retort through exhaust pipe at the bottom of retort. The pyrolysis occurred at the temperature about . By time-being, the combustion zones moved downward, and the char (semi-coke) produced as a solid residue of pyrolysis, ignited to burn as additional fuel for combustion. This caused the pyrolysis zone to move downward to the lower parts of retort | https://en.wikipedia.org/wiki?curid=23515462 |
Nevada–Texas–Utah retort After combustion zone reached to the bottom of retort, air injection was stopped to stop combustion. After burning of char, the shale oil production ceased and only spent oil shale ash remained in the retort. The bottom of retort could opened for removal of the oil shale ash after retorting process. Operating the NTU retort with nominal capacity of 40 ton of raw oil shale, the full process cycle took about 40 hours. The shale oil yield varied from 80% to 85% of Fischer assay. The advantage of the NTU retort process was simple design, simple operation, and limited need for external fuel. It was suitable for processing of wide variety of oil shales. The disadvantage of this process was a batch mode of operation not allowing continuous retorting, and therefore having small capacity being labor extensive at the same time. The process also had a relatively low oil yield and it required cooling water. | https://en.wikipedia.org/wiki?curid=23515462 |
Heated glass is a resistance heater created when a transparent, electrically conductive coating is applied to float glass and then subjected to an electric current. The electric current in the coating creates heat energy, which warms the glass until the glass radiates heat. The manufacturing process begins with the application of a microscopic Tin dioxide coating to a pane of float glass. This coating is transparent and conducts electricity. Then, two busbars are applied to the glass as follows: the busbars must be parallel and applied to opposing edges on the same side of the glass pane. The surface of the glass between the busbars must be flat. An electric current flows across the tin(II) oxide coating from one busbar to the other. The electrical resistance of the coating produces heat energy, which radiates from the glass. The busbars are connected to a power control unit that regulates the flow of electricity and thus the temperature of the glass. In modern architectural projects the heated glass is completely translucent. This technology uses a special metallic coating on the surface of the glass invisible to the naked human eye. A pane of heated glass can achieve temperatures up to 350 degrees Fahrenheit (177 degrees Celsius). The standard desirable temperature range in buildings is between 104 and 113 degrees Fahrenheit (40 to 44 degrees Celsius). For industrial purposes higher temperatures may be warranted. The first heated glass was created in 1931 by Protes Glass Company, offered for cars | https://en.wikipedia.org/wiki?curid=23515759 |
Heated glass Their product was not a success. was first used on a wide scale in World War II to prevent aircraft windshields from frosting over in cold weather and high altitudes. It is still used in aviation for this purpose. has been used in architectural applications for the past 30 years to prevent condensation and provide radiant heat. Condensation in buildings can have serious consequences to health and property values. Heated or radiant glass is generally an enhanced standard two pane insulated glass window using various bus bar technologies to convey the electric current to heat the glass. Some technologies are patented and permit larger glass areas to be heated than others. In One university study shows that this heated glass technology is more efficient than other electric heating and can be more efficient than natural gas heating. Some environmentalists dispute the idea that this is an efficient heating system because even high e-value windows are poor insulators compared to insulated walls, and they believe heating window ejects much of the radiant heat outside. Another criticism is that this type of heating may encourage the use of larger windows in a house, making them less energy efficient. This technology has evolved since the late 1950s where it firstly evolved to be used for melting snow on glass roofs and was then effectively inverted and used as the heat source inside the building. A common commercial use of heated glass is to prevent frost from forming on the glass doors of supermarket freezers | https://en.wikipedia.org/wiki?curid=23515759 |
Heated glass In addition, display cases (such as in convenience stores and delis) use heated glass shelves to keep cooked food items from cooling. | https://en.wikipedia.org/wiki?curid=23515759 |
C27H46O The molecular formula CHO (molar mass: 386.65 g/mol, exact mass: 386.354866) may refer to: | https://en.wikipedia.org/wiki?curid=23522400 |
C19H22N2O The molecular formula CHNO may refer to: | https://en.wikipedia.org/wiki?curid=23522474 |
C9H8O The molecular formula CHO may refer to: | https://en.wikipedia.org/wiki?curid=23522567 |
C9H10O The molecular formula CHO (molar mass: 134.17 g/mol) may refer to: | https://en.wikipedia.org/wiki?curid=23522706 |
C8H6N2 The molecular formula CHN may refer to: | https://en.wikipedia.org/wiki?curid=23522754 |
Enthalpy of fusion The enthalpy of fusion of a substance, also known as (latent) heat of fusion is the change in its enthalpy resulting from providing energy, typically heat, to a specific quantity of the substance to change its state from a solid to a liquid, at constant pressure. For example, when melting 1 kg of ice (at 0 °C under a ), 333.55 kJ of energy is absorbed with no temperature change. The heat of solidification (when a substance changes from liquid to solid) is equal and opposite. This energy includes the contribution required to make room for any associated change in volume by displacing its environment against ambient pressure. The temperature at which the phase transition occurs is the melting point or the freezing point, according to context. By convention, the pressure is assumed to be unless otherwise specified. The 'enthalpy' of fusion is a latent heat, because during melting the heat energy needed to change the substance from solid to liquid at atmospheric pressure is latent heat of fusion, as the temperature remains constant during the process. The latent heat of fusion is the enthalpy change of any amount of substance when it melts. When the heat of fusion is referenced to a unit of mass, it is usually called the specific heat of fusion, while the molar heat of fusion refers to the enthalpy change per amount of substance in moles. The liquid phase has a higher internal energy than the solid phase | https://en.wikipedia.org/wiki?curid=23523889 |
Enthalpy of fusion This means energy must be supplied to a solid in order to melt it and energy is released from a liquid when it freezes, because the molecules in the liquid experience weaker intermolecular forces and so have a higher potential energy (a kind of bond-dissociation energy for intermolecular forces). When liquid water is cooled, its temperature falls steadily until it drops just below the line of freezing point at 0 °C. The temperature then remains constant at the freezing point while the water crystallizes. Once the water is completely frozen, its temperature continues to fall. The enthalpy of fusion is almost always a positive quantity; helium is the only known exception. Helium-3 has a negative enthalpy of fusion at temperatures below 0.3 K. Helium-4 also has a very slightly negative enthalpy of fusion below . This means that, at appropriate constant pressures, these substances freeze with the addition of heat. In the case of He, this pressure range is between 24.992 and . These values are mostly from the CRC "Handbook of Chemistry and Physics", 62nd edition. The conversion between cal/g and J/g in the above table uses the thermochemical calorie (cal) = 4.184 joules rather than the International Steam Table calorie (cal) = 4.1868 joules. A) To heat 1 kg (1.00 liter) of water from 283.15 K to 303.15 K (10 °C to 30 °C) requires 83.6 kJ. However, to melt ice also requires energy. We can treat these two processes independently; thus, to heat 1 kg of ice from 273.15 K to water at 293 | https://en.wikipedia.org/wiki?curid=23523889 |
Enthalpy of fusion 15 K (0 °C to 20 °C) requires: From these figures it can be seen that one part ice at 0 °C will cool almost exactly 4 parts water from 20 °C to 0 °C. B) Silicon has a heat of fusion of 50.21 kJ/mol. 50 kW of power can supply the energy required to melt about 100 kg of silicon in one hour, after it is brought to the melting point temperature: 50 kW = = /h * (1 mol Si)/ * /(mol Si) * / = The heat of fusion can also be used to predict solubility for solids in liquids. Provided an ideal solution is obtained the mole fraction formula_1 of solute at saturation is a function of the heat of fusion, the melting point of the solid formula_2 and the temperature (T) of the solution: Here, R is the gas constant. For example, the solubility of paracetamol in water at 298 K is predicted to be: This equals to a solubility in grams per liter of: formula_5 which is a deviation from the real solubility (240 g/L) of 11%. This error can be reduced when an additional heat capacity parameter is taken into account. At equilibrium the chemical potentials for the pure solvent and pure solid are identical: or with formula_8 the gas constant and formula_9 the temperature. Rearranging gives: and since the heat of fusion being the difference in chemical potential between the pure liquid and the pure solid, it follows that Application of the Gibbs–Helmholtz equation: ultimately gives: or: and with integration: the end result is obtained: | https://en.wikipedia.org/wiki?curid=23523889 |
Rapid phase transition or RPT is a phenomenon realized in liquefied natural gas (LNG) incidents in which LNG vaporizes violently upon coming in contact with water causing what is known as a "physical explosion" or "cold explosion". During such explosions there is no combustion but rather a huge amount of energy is transferred in the form of heat from the room-temperature water to the LNG at a temperature difference of about 175 kelvins. Liquefied natural gas or LNG is a natural gas that gets liquefied at atmospheric pressure and −161.5 °C. It is odorless, tasteless, colorless, and not poisonous but causes asphyxia. It can cause frostbite due to its cryogenic temperature. If this extremely cold LNG is mixed with water(e.g. sea water, which has an average temperature of 15 °C), heat energy is transferred from the water to the LNG, rapidly vaporizing it from its liquefied state back into its original gaseous state. This results in an explosion because the volume occupied by natural gas in its gaseous form is 600 times greater than when its liquefied. This is the phenomenon of rapid phase transition. | https://en.wikipedia.org/wiki?curid=23524398 |
C9H6O2 The molecular formula CHO (molar mass: 146.14 g/mol, exact mass: 146.036779) may refer to: | https://en.wikipedia.org/wiki?curid=23524651 |
C4H9N3O2 The molecular formula CHNO may refer to: | https://en.wikipedia.org/wiki?curid=23524665 |
C9H12 The molecular formula CH may refer to: | https://en.wikipedia.org/wiki?curid=23524758 |
C6H9N3O2 The molecular formula CHNO may refer to: | https://en.wikipedia.org/wiki?curid=23524832 |
C13H24N2O The molecular formula CHNO may refer to: | https://en.wikipedia.org/wiki?curid=23524936 |
Effect of oxygen on chronic obstructive pulmonary disease In some individuals, the effect of oxygen on chronic obstructive pulmonary disease is to cause increased carbon dioxide retention, which may cause drowsiness, headaches, and in severe cases lack of respiration, which may lead to death. People with lung ailments or with central respiratory depression, who receive supplemental oxygen, require careful monitoring. In individuals with chronic obstructive pulmonary disease and similar lung problems, the clinical features of oxygen toxicity are due to high carbon dioxide content in the blood (hypercapnia). This leads to drowsiness (narcosis), deranged acid-base balance due to respiratory acidosis, and death. Many people with chronic obstructive pulmonary disease have a low partial pressure of oxygen in the blood. Treatment with supplemental oxygen may improve their well-being; alternatively, in some this can lead to the adverse effect of elevating the carbon dioxide content in the blood (hypercapnia) to levels that may become toxic. In individuals with chronic obstructive pulmonary disease who receive supplemental oxygen, carbon dioxide accumulation may occur through two main mechanisms: In people with chronic obstructive pulmonary disease, carbon dioxide toxicity can be prevented by careful control of the supplemental oxygen. In those with an acute exacerbation of COPD, hypoxic pulmonary vasoconstriction can improve gas exchange, and so just enough oxygen is given to maintain an oxygen saturation of 88%–92%. | https://en.wikipedia.org/wiki?curid=23527304 |
C4H5N3O The molecular formula CHNO may refer to: | https://en.wikipedia.org/wiki?curid=23527703 |
Baeyer–Emmerling indole synthesis The is a method for synthesizing indole from a (substituted) "ortho"-nitrocinnamic acid and iron powder in strongly basic solution. This reaction was discovered by Adolf von Baeyer and Adolph Emmerling in 1869. The reaction of iron powder with "o"-nitrocinnamic acid reduces the nitro group to a nitroso. The nitrogen then condenses with a carbon on the alkene chain with loss of a molecule of water to form a ring. Decarboxylation gives indole. | https://en.wikipedia.org/wiki?curid=23533752 |
International Academy of Mathematical Chemistry The (IAMC) was founded in Dubrovnik (Croatia) in 2005 by Milan Randić. It is an organization for chemistry and mathematics avocation, and its predecessors have been around since the 1930s. The Academy Members are 88 (2011) from all over the world (27 countries), comprising six scientists awarded the Nobel Prize. | https://en.wikipedia.org/wiki?curid=23534720 |
C10H18 The molecular formula CH may refer to: | https://en.wikipedia.org/wiki?curid=23536207 |
Cryogenic nitrogen plant Nitrogen, as an element of great technical importance, can be produced in a cryogenic nitrogen plant with a purity of more than 99.9999%. Air inside a distillation column is separated at cryogenic temperatures (about 100K/-173°C) to produce high purity nitrogen with 1ppm of impurities. The process is based on the air separation, which was invented by Dr. Carl von Linde in 1895. The main purpose of a cryogenic nitrogen plant is to provide a customer with high purity gaseous nitrogen (GAN). In addition liquid nitrogen (LIN) is produced simultaneously and is typically 10% of the gas production. High purity liquid nitrogen produced by cryogenic plants is stored in a local tank and used as a strategic reserve. This liquid can be vaporised to cover peaks in demand or for use when the nitrogen plant is offline. Typical cryogenic nitrogen plants range from 250 Nm³/hour to very large range plants with a daily capacity of 63.000 tonnes of nitrogen a day (as the Cantarell Field plant in Mexico). A cryogenic nitrogen plant comprises: Atmospheric air is roughly filtered and pressurised by a compressor, which provides the product pressure to deliver to the customer. The amount of air sucked in depends on the customer’s nitrogen demand. The Air Receiver collects condensate and minimises pressure drop. The dry and compressed air leaves the air to refrigerant heat exchanger at about 10°C. To clean the process air further, there are different stages of filtration | https://en.wikipedia.org/wiki?curid=23542186 |
Cryogenic nitrogen plant First of all, more condensate is removed, this removes some hydrocarbons. The last unit process in the warm end container is the thermal swing adsorber (TSA). The Air purification unit cleans the compressed process air by removing any residual water vapour, carbon dioxide and hydrocarbons. It comprises two vessels, valves and exhaust to allow the changeover of vessels. While one of the TSA beds is on stream the second one is regenerated by the oxygen rich waste flow, which is vented through a silencer into the ambient environment. After leaving the air purification unit, the process air enters the main heat exchanger, where it is rapidly cooled down to -165°C. All residual impurities (e.g. CO) freeze out, and the process air enters at the bottom of the distillation column partially liquefied. Liquid Nitrogen produced from the cold box transfers into the liquid storage tank. An ambient air vaporiser is used to vaporise stored liquid during peak demand. A pressure control panel senses the demand for gaseous nitrogen and regulates the gas flow into the end-users pipeline to maintain line pressure. | https://en.wikipedia.org/wiki?curid=23542186 |
Cryogenic oxygen plant A cryogenic oxygen plant is an industrial facility that creates molecular oxygen at relatively high purity. Oxygen is the most common element in the earth's crust and the second largest industrial gas. This process was pioneered by Dr. Carl von Linde in 1902. The cryogenic air separation achieves high purity oxygen of more than 99.5%. The resulting high purity product can be stored as a liquid and/or filled into cylinders. These cylinders can even be distributed to customer in the medical sector, welding or mixed with other gases and used as breathing gas for diving. Typical production ranges from 50 normal m/hour up to 860,000 Nm/hour (Ras Laffan refinery). A cryogenic oxygen plant comprises: Atmospheric air is roughly filtered and pressurised by a compressor, which provides the product pressure to deliver to the customer. The amount of air sucked in depends on the customer’s oxygen demand. The air receiver collects condensate and minimises pressure drop. The dry and compressed air leaves the air to refrigerant heat exchanger with about 10°C. To clean the process air further, there are different stages of filtration. First of all, more condensate is removed, then a coalescing filter acts as a gravity filter and finally an adsorber filled with activated carbon removes some hydrocarbons. The last unit process in the warm end container is the thermal swing adsorber (TSA). The Air purification unit cleans the compressed process air by removing any residual water vapour, carbon dioxide and hydrocarbons | https://en.wikipedia.org/wiki?curid=23542335 |
Cryogenic oxygen plant It comprises two vessels, valves and exhaust to allow the changeover of vessels. While one of the TSA beds is on stream the second one is regenerated by the waste gas flow, which is vented through a silencer into the ambient environment. The process air enters the main heat exchanger in the coldbox where it is cooled in counter flow with the waste gas stream. After leaving the main heat exchanger the process air has a temperature of about –112°C and is partly liquefied. The complete liquefaction is achieved through evaporation of cooled liquid oxygen in the boiler. After passing a purity control valve process air enters on tip of the distillation column and flows down through the packing material. The steam of evaporated oxygen vapour in the shell of the boiler vents back into the distillation column. It rises through the column packing material and encounters the descending stream of liquid process air. The liquid air descending down the column loses nitrogen. It becomes richer in oxygen and collects at the base of the column as pure liquid oxygen. It flows out into the boiler to the cold box liquid product valve. An on-line oxygen analyser controls the opening of the liquid product valve to transfer pure low-pressure liquid oxygen into the storage tank. The rising oxygen vapour becomes rich in nitrogen and argon. It leaves the column and exits the cold box at ambient temperature through the main heat exchanger as a waste gas | https://en.wikipedia.org/wiki?curid=23542335 |
Cryogenic oxygen plant This waste gas provides purge gas to regenerate the TSA unit and to the cool the refrigeration turbine. Turbines located at the base of the cold box provide refrigeration for the process. A stream of high-pressure gas from the main heat exchangers is cooled and expanded to low pressure in the turbine. This cold air returns to the waste stream of the heat exchanger to inject refrigeration. Energy removed by the turbine re-appears as heat in the turbine’s closed-cycle air-brake circuit. This heat is removed in an air-to-air cooler by waste gas from the cold box. Liquid from the tank is compressed to high pressure in a cryogenic liquid pump. It is then vaporised in an ambient air evaporator to produce gaseous oxygen. The high-pressure gas then can pass into cylinders via the gas manifold or fed into a customers product pipeline. | https://en.wikipedia.org/wiki?curid=23542335 |
Copper(II) phosphate (not to be confused with copper(I) phosphate) is an inorganic compound consisting of copper cations and the phosphate anions; with the chemical formula Cu(PO). It may also be regarded as the cupric salt of phosphoric acid. It is commonly encountered as the hydrated species Cu(PO)OH, which is green and occurs naturally as the mineral libethenite. Anhydrous copper(II) phosphate is blue with triclinic crystals and can be produced by a high-temperature reaction between diammonium phosphate and copper(II) oxide. | https://en.wikipedia.org/wiki?curid=23545710 |
Dynamic vapor sorption (DVS) is a gravimetric technique that measures how quickly and how much of a solvent is absorbed by a sample: such as a dry powder absorbing water. It does this by varying the vapor concentration surrounding the sample and measuring the change in mass which this produces. Water vapor is most commonly used, but it is also possible to use a wide range of organic solvents. Dr Daryl Williams, founder of Surface Measurement Systems Ltd, invented Dynamic Vapor Sorption in 1991 and the first instrument was delivered to Pfizer UK in 1992. DVS was originally developed to replace the time and labor-intensive desiccators and saturated salt solutions to measure water vapor sorption isotherms. The main application of DVS is to measure water sorption isotherms. In general, a vapor sorption isotherm shows the equilibrium amount of vapor sorbed as a function of steady state relative vapor pressure at a constant temperature. For water sorption isotherms, water relative vapor pressure is more commonly expressed as relative humidity. In a DVS experiment this is accomplished by exposing a sample to a series of step changes in relative humidity and monitoring the mass change as a function of time. The sample mass must be allowed to reach gravimetric equilibrium at each step change in humidity before progressing to the next humidity level. Then, the equilibrium mass values at each relative humidity step are used to generate the isotherm | https://en.wikipedia.org/wiki?curid=23547123 |
Dynamic vapor sorption Isotherms are typically divided into two components: "sorption" for increasing humidity steps and "desorption" for decreasing humidity steps. Sorption can be further divided into "adsorption" (sorbate located on the surface) and "absorption" (sorbate penetrates the bulk). Figure 1 shows a typical water sorption result from a DVS experiment for a microcrystalline cellulose sample. The kinetic data (Figure 1a) shows the change in mass and humidity as a function of time. From the kinetic results, the rate of water uptake and water diffusion coefficients can be determined. The equilibrium mass values at the end of each humidity step were used to calculate the sorption and desorption isotherms (Figure 1b). The difference in water vapor uptake between the sorption and desorption isotherms is called the hysteresis. The shape and location of the isotherm hysteresis can elucidate information about the sorption mechanism and sample porosity. Although an isotherm experiment is the most common use of a DVS instrument, humidity (or other vapor) ramping experiments can be performed to investigate vapor-induced phase changes. These changes include: glassy to rubbery transitions, amorphous to crystalline conversions, and sample deliquescence. DVS measurement has applications over a wide range of industries. Both equilibrium vapor sorption isotherms and vapor sorption kinetic results can yield vital information for materials ranging from pharmaceuticals to fuel cells | https://en.wikipedia.org/wiki?curid=23547123 |
Dynamic vapor sorption Although water sorption experiments are most common, the use of organic vapor in DVS experiments can reveal additional sample properties. The below sections highlight how DVS experiments are utilized in several industries. The moisture sorption properties of pharmaceutical materials such as excipients, drug formulations and packaging films are recognized as critical factors in determining their storage, stability, processing and application performance. Further, vapor sorption experiments can be used to study hydrate and solvate formation. Gravimetric vapor sorption experiments are one of the most sensitive methods for determining amorphous contents, which may have a detrimental impact on the stability, manufacturability and dissolution characteristics of the formulated drug product. The moisture sorption properties of food products are recognized as critical factors in determining their storage, stability, processing and application performance. DVS is also used to measure moisture and flavor diffusion properties for packaging and barrier applications. Further, moisture sorption plays critical roles in the storage and performance of agricultural products like pesticides, herbicides, fertilizers, and seeds. DVS experiments have been widely used in the study of personal care materials. For instance, the moisturization of hair samples with different chemical (i.e. conditioning, coloring, and bleaching) and mechanical (i.e. perming, combing, and blow-drying) treatments | https://en.wikipedia.org/wiki?curid=23547123 |
Dynamic vapor sorption The hydration behavior of skin samples has also been studied by DVS. Other moisture sorption applications related to the personal care industry include the dehydration of contact lenses and superabsorbent polymers. In particular to building materials, moisture sorption has significant implications for cements, woods, insulation materials, and fibers. Moisture damage is a significant factor limiting a building’s lifespan. As well, moisture infusion through a building’s outer structure can have a significant effect on indoor air quality and air-conditioning load. A critical parameter affecting the performance of proton exchange membranes is the water content. Water is typically supplied to the fuel cell by humidifying the gas feed stream. The level of hydration within the proton exchange membrane is vital to its performance: if the hydration level is too low, the polymers exhibit greatly reduced ionic conductivity; if hydration level is too high, excess water can flood the pores in the gas diffusion layer and impede mass transport within the electrode structure. For these reasons, DVS has been used to study the water sorption and transport properties of proton exchange membranes. | https://en.wikipedia.org/wiki?curid=23547123 |
EMF measurement EMF measurements are measurements of ambient (surrounding) electromagnetic fields that are performed using particular sensors or probes, such as EMF meters. These probes can be generally considered as "antennas" although with different characteristics. In fact probes should not perturb the electromagnetic field and must prevent coupling and reflection as much as possible in order to obtain precise results. There are two main types of EMF measurements: EMF probes may respond to fields only on one axis, or may be tri-axial, showing components of the field in three directions at once. Amplified, active, probes can improve measurement precision and sensitivity but their active components may limit their speed of response. Measurements of the EMF are obtained using an E-field sensor or H-field sensor which can be isotropic or mono-axial, active or passive. A mono-axial, omnidirectional probe is a device which senses the Electric (short dipole) or Magnetic field linearly polarized in a given direction. Using a mono-axial probe implies the need for three measurements taken with the sensor axis set up along three mutually orthogonal directions, in a "X, Y, Z" configuration. As an example, it can be used as a probe which senses the Electric field component parallel to the direction of its axis of symmetry | https://en.wikipedia.org/wiki?curid=23547932 |
EMF measurement In these conditions, where E is the amplitude of incident electric field, and θ is the amplitude of the angle between sensor axis and direction of electric field E, the signal detected is proportional to |E|cos θ ("right"). This allows obtainment of the correct total amplitude of the field in the form of or, in case of the magnetic field An isotropic (tri-axial) probe simplifies the measurement procedure because the total field value is determined with three measures taken without changing sensor position: this results from the geometry of the device which is made by three independent broadband sensing elements placed orthogonal to each other. In practice, each element’s output is measured in three consecutive time intervals supposing field components being time stationary . An "EMF meter" is a scientific instrument for measuring electromagnetic fields (abbreviated as EMF). Most meters measure the electromagnetic radiation flux density (DC fields) or the change in an electromagnetic field over time (AC fields), essentially the same as a radio antenna, but with quite different detection characteristics. The two largest categories are single axis and tri-axis. Single axis meters are cheaper than tri-axis meters, but take longer to complete a survey because the meter only measures one dimension of the field. Single axis instruments have to be tilted and turned on all three axes to obtain a full measurement. A tri-axis meter measures all three axes simultaneously, but these models tend to be more expensive | https://en.wikipedia.org/wiki?curid=23547932 |
EMF measurement Electromagnetic fields can be generated by AC or DC currents. An EMF meter can measure AC electromagnetic fields, which are usually emitted from man-made sources such as electrical wiring, while gaussmeters or magnetometers measure DC fields, which occur naturally in Earth's geomagnetic field and are emitted from other sources where direct current is present. As most electromagnetic fields encountered in everyday situation are those generated by household or industrial appliances, the majority of EMF meters available are calibrated to measure 50 and 60 Hz alternating fields (the frequency of European and US mains electricity). There are other meters which can measure fields alternating at as low as 20 Hz, however these tend to be much more expensive and are only used for specific research purposes. Active sensors are sensing devices which contain active components; usually this solution allows for a more precise measurement with respect to passive components. In fact, a passive receiving antenna collects energy from the electromagnetic field being measured and makes it available at a RF cable connector. This signal then goes to the spectrum analyzer but the field characteristics can be someway modified by the presence of the cable, especially in near-field conditions. On the other hand, an effective solution is to transfer on an optical carrier, the electric (or magnetic) field component sensed with an active probe | https://en.wikipedia.org/wiki?curid=23547932 |
EMF measurement The basic components of the system are a receiving electro-optical antenna which is able to transfer, on an optical carrier, the individual electric (or magnetic) field component picked up and to return it in the form of an electrical signal at the output port of an opto-electric converter. The modulated optical carrier is transferred by means of a fiber-optic link to a converter which extracts the modulating signal and converts it back to an electrical signal. The electrical signal thus obtained can be then sent to a spectrum analyzer with a 50 Ω common RF cable. Isotropic deviation, in EMF measurements, is a parameter that describes the accuracy in measuring field intensities irrespective of the probe’s orientation. If the field is obtained by three measurements in an orthogonal "X, Y, Z" configuration in the form: a sufficient condition for the expression to be true for every three orthogonal coordinates "(X,Y,Z) " is for the probe radiation pattern to be as close as possible to ideal short dipole pattern, called sin θ: where A is function of frequency. The difference between ideal dipole radiation pattern and real probe pattern is called "isotropic deviation". Bibliography | https://en.wikipedia.org/wiki?curid=23547932 |
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