TY - JOUR. T1 - Rate constants and kinetic deuterium isotope effects for hydrogen atom abstraction from phenols by polyvinyl acetate radical. AU - Simonyi, Miklós. AU - Fitos, Ilona. AU - Kardos, Julianna. AU - Lukovits, István. AU - Pospišil, Jan. PY - 1975/1/1. Y1 - 1975/1/1. N2 - The primary kinetic deuterium isotope effect (PKIE) for the hydrogen atom abstraction from substituted phenols by polyvinyl acetate radical shows a large variation, and shows a maximum as a function of the reactivity of the compounds; the high values of PKIE may be attributed to tunnelling.. AB - The primary kinetic deuterium isotope effect (PKIE) for the hydrogen atom abstraction from substituted phenols by polyvinyl acetate radical shows a large variation, and shows a maximum as a function of the reactivity of the compounds; the high values of PKIE may be attributed to tunnelling.. UR - http://www.scopus.com/inward/record.url?scp=37049127504&partnerID=8YFLogxK. UR - ...
Deuterium isotope effects on 13C-NMR chemical shifts are investigated in a series of 10-hydroxybenzo[h]quinolines (HBQs) The OH proton is deuteriated. The isotope effects on 13C chemical shifts in these hydrogen bonded systems are rather unusual. The formal four-bond effects are found to be negative, indicating transmission via the hydrogen bond. In addition unusual long-range effects are seen. Structures, NMR chemical shifts and changes in nuclear shieldings upon deuteriation are calculated using DFT methods. Two-bond deuterium isotope effects on 13C chemical shifts are correlated with calculated OH stretching frequencies. Isotope effects on chemical shifts are calculated for systems with OH exchanged by OD. Hydrogen bond potentials are discussed. New and more soluble nitro derivatives are synthesized.
Deuterium isotope effects on 13C-NMR chemical shifts are investigated in a series of 10-hydroxybenzo[h]quinolines (HBQs) The OH proton is deuteriated. The isotope effects on 13C chemical shifts in these hydrogen bonded systems are rather unusual. The formal four-bond effects are found to be negative, indicating transmission via the hydrogen bond. In addition unusual long-range effects are seen. Structures, NMR chemical shifts and changes in nuclear shieldings upon deuteriation are calculated using DFT methods. Two-bond deuterium isotope effects on 13C chemical shifts are correlated with calculated OH stretching frequencies. Isotope effects on chemical shifts are calculated for systems with OH exchanged by OD. Hydrogen bond potentials are discussed. New and more soluble nitro derivatives are synthesized ...
Keywords: ab initio calculations ; cycloaddition ; heterocycles ; isotope effects ; sulfur dioxide ; Transition-state structure ; cheletropic additions ; pi-pi ; mechanisms ; competition ; acid ; stereoselectivity ; regioselectivity ; cycloadditions ; 1 ; 3-dienes ; cycloadditions. Note: Swiss Fed Inst Technol, Inst Mol & Biol Chem, BCH, CH-1015 Lausanne, Switzerland. Univ Oviedo, Dept Quim Fis & Analit, Lab Quim Computac, E-33071 Oviedo, Principado Astu, Spain.. ...
Departments of Pharmacokinetics Dynamics and Metabolism (R.S., T.J.S., H.G., A.J.C., R.S.O., S.L.R., D.K.S., L.M.T., A.D.N.V.) and Pharmaceutical Sciences (K.S.), Pfizer Global Research and Development, Groton, ...
Scientists have found a new method to strategically add deuterium to benzene, an aromatic compound commonly found in crude oil. When applied to the active ingredient of drugs to incorporate deuterium, it could dramatically improve the drugs efficacy and safety and even introduce new medicines.. To validate the method, which was published in Nature, a team led by W. Dean Harman of the University of Virginia worked with Xiaoping Wang at the Oak Ridge National Laboratorys Spallation Neutron Source. Wang successfully verified the exact position of deuterium atoms that resulted from the selective deuteration of benzene molecules using single crystal neutron diffraction.. "Because the high sensitivity of neutrons to hydrogen and its deuterium isotope, we were able to quantitatively assign not only the positions of the deuterium atoms at the atomic level, but also determine precisely how many were added on each side of the benzene molecule," Wang said. "This is important in designing new therapeutic ...
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Deuterium is an isotope of hydrogen, the first element. Deuterium has one proton and one neutron. Hydrogen does not have a neutron, only a proton. Another isotope of hydrogen, tritium, has two neutrons. The chemical symbol for Deuterium is 2H but D is also used often. Two deuterium atoms combined with an oxygen atom is sometimes called "heavy water." This is because it is like water (H2O), but heavier because deuterium has one more neutron in its nucleus. Heavy water is sometimes used in nuclear reactors. It is also used as a solvent for NMR spectroscopy. This is because it will dissolve the sample, like normal water, but it will not be detected by the magnet in an 1H NMR. ...
article{2cb5d1fd-a9b2-4971-a2e2-242f5f3c8278, abstract = {We present a first time-resolved deuterium NMR study on wormlike,br/,,br, micelles under shear. For the investigation, a micellar system made of,br/,,br, soybean phosphatidylcholine (lecithin), D2O, and cyclohexane was,br/,,br, studied in the concentrated regime, in the vicinity of the,br/,,br, isotropic/nematic transition but positioned in the equilibrium,br/,,br, isotropic phase. The D2O dispersed in the micellar core was used as a,br/,,br, probe to study the relaxation of a shearing-induced nematic phase back,br/,,br, to the isotropic liquid state, after cessation of shear. The whole,br/,,br, process was followed through time-resolved deuterium spectra and was,br/,,br, characterized by a continuous decrease of the measured quadrupolar,br/,,br, splitting, proportional to the nematic order parameter.}, author = {Angelico, R and Burgemeister, D and Ceglie, A and Olsson, Ulf and Palazzo, G and Schmidt, C}, issn = {1520-5207}, language = ...
TY - JOUR. T1 - Possibility of separation of deuterium from natural hydrogen by a palladium particle bed. AU - Fukada, Satoshi. AU - Fujiwara, Hiroshi. PY - 1999/12/1. Y1 - 1999/12/1. N2 - Deuterium in natural hydrogen can be successfully concentrated by means of frontal chromatography using a Pd particle bed at room temperature. The deuterium concentration at the outlet reaches a maximum immediately after hydrogen breaks through the bed. The outlet concentration curve is correlated to a unified profile based on the plate model regardless of the gaseous flow rate and the inlet deuterium concentration. The height equivalent to a theoretical plate, HETP, decreases from 7.6 to 4.7 mm with an increase of the flow rate from 15 to 87 mL(NTP)/min.. AB - Deuterium in natural hydrogen can be successfully concentrated by means of frontal chromatography using a Pd particle bed at room temperature. The deuterium concentration at the outlet reaches a maximum immediately after hydrogen breaks through the bed. ...
Isotopic substitution can lead to changes in the values of equilibrium constants, especially if hydrogen is replaced by deuterium (or tritium).[16] This equilibrium isotope effect is analogous to the kinetic isotope effect on rate constants, and is primarily due to the change in zero-point vibrational energy of H-X bonds due to the change in mass upon isotopic substitution.[16] The zero-point energy is inversely proportional to the square root of the mass of the vibrating hydrogen atom, and will therefore be smaller for a D-X bond that for an H-X bond.. An example is a hydrogen atom abstraction reaction R + H-R ⇌ R-H + R with equilibrium constant KH, where R and R are organic radicals such that R forms a stronger bond to hydrogen than does R. The decrease in zero-point energy due to deuterium substitution will then be more important for R-H than for R-H, and R-D will be stabilized more than R-D, so that the equilibrium constant KD for R + D-R ⇌ R-D + R is greater than KH. This is ...
Deuterium fusion breakthrough: Triton is currently the strongest radiation source of energy 500 times - Sohu military channel map Z (Z machine). Pictures from the network of nuclear fusion research into a new stage. According to the U.S. science magazine online edition reported that in November 15th, the U.S. Department of energys Sandy National Laboratory in the days before the worlds strongest radiation source - the Z (Z machine) device opens the deuterium tritium - controlled nuclear fusion experiment. When the ratio of deuterium tritium in the future reaches 50: 50, it will produce the energy of the current maximum energy of 500 times. Controlled nuclear fusion, if successful, can almost make people out of the energy crisis. Raw materials: the hydrogen isotope deuterium required from seawater can be extracted, it is estimated that 1 liters of water extract in deuterium if fully participate in the fusion reaction, the energy released is equivalent to 300 liters of gasoline combustion ...
Protium/deuterium fractionation factors have been widely used to study the strength and geometry of hydrogen bonds in proteins. These studies have shown that amide hydrogen bonds in proteins have fractionation factors in the range of 0.28 to 1.47 (1). A
The current study was approved by the Bioethics Committee of the Oncology Rostov Research Institute of Russian Health Ministry, protocol No. 3 from 14.03.2014. The current study respected the international rules of human treatment of experimental animals. The experiments were conducted on 37 white outbred female rats: 10 young animals (age: 8 - 10 months, weight: 210 ± 12 g) and 27 presenile rats (age 20 - 22 months, weight: 291 ± 32 g), that were divided into group 1 (n = 13) and group 2 (n = 14). In contrast to the rats in group 2 and group young, the animals in group 1 received DDW with a deuterium content of 46 ± 2 ppm in a volume of 25 to 30 mL per day per head (rat) for three weeks. According to NMR (nuclear magnetic resonance) spectroscopy, DDW contained about three times less deuterium than the natural water of the region where these rats lived (150 ± 2 ppm). Deuterium depleted water was produced on a plant designed in the Kuban State University, by the electrolytic decomposition ...
This thesis describes the development and the use of quantitative deuterium Nuclear Magnetic Resonance spectroscopy (NMR) as a tool in two areas of environmental research: the study of long term climate-plant interactions and the source tracking of persistent organic pollutant.. Long-term interactions between plants and climate will influence climate change during this century and beyond, but cannot be studied in manipulative experiments. We propose that long tree rings series can serve as records for tracking such interactions during past centuries.. The abundance of the stable hydrogen isotope deuterium (D) is influenced by physical and biochemical isotope fractionations. Because the overlapping effects of these fractionations are not understood, studies of the D abundance of tree rings led to conflicting results. We hypothesized that both types of fractionations can be separated if the D abundance of individual C-H groups of metabolites can be measured, that is if individual D isotopomers are ...
In this work we present results about the deuterium isotope effect on the globalkinetics of a Belousov-Zhabotinsky reaction in batch conditions. A nonlinear dependenceof the Induction Period upon the percentage of deuterated reactants was found. The isotopiceffect on the bromination reaction of malonic acid was evaluated.
Formic acid (HCOOH) decomposes efficiently to afford H2 and CO2 selectively in the presence of a catalytic amount of a water-soluble rhodium aqua complex, [RhIII(Cp*)(bpy)(H2O)]2+(Cp*=pentamethylcyclopentadienyl, bpy=2,2′-bipyridine) in aqueous solution at 298 K. No CO was produced in this catalytic decomposition of HCOOH. The decomposition rate reached a maximum value at pH 3.8. No deterioration of the catalyst was observed during the catalytic decomposition of HCOOH, and the catalytic activity remained the same for the repeated addition of HCOOH. The rhodium-hydride complex was detected as the catalytic active species that undergoes efficient H/D exchange with water. When the catalytic decomposition of HCOOH was performed in D2O, D2 was produced selectively. Such an efficient H/D exchange and the observation of a deuterium kinetic isotope effect in the catalytic decomposition of DCOOH in H2O provide valuable mechanistic insight into this efficient and selective decomposition process. ...
The results of a computer program written to study rotational dynamics by following the reorientation of a carbon-deuterium (C-D) bond vector in a deuteriated molecule are described. Three-dimensional plots are constructed to show how deuterium nuclear magnetic resonance splittings vary as a function of two rotational parameters. It is suggested that these diagrams provide insight into the rotational motions of the molecule. © 1987 American Chemical Society.
Deuterium is used for pharmaceuticals and product development for its ability to be used for radiolabeling. Isowaters® move to refining deuterium in a step closer to insuring the worlds supply for deuterium.. www.technologynetworks.com/analysis/articles/shining-a-light-on-drug-development-revolutionizing-radiolabeling-294063 ...
Deuterium atom is an isotope of hydrogen [NP]e- that is a fermion. Would it be correct the model the deuteron [NP] nucleus as a boson, given that it has even number of particles ? That is, would it be correct to say that two deuteron [NP], as bosons, could occupy the same particle state because the Pauli Exclusion would not apply ...
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Top ] [ deuterium ] [ Subroutines ]. NAME. subroutine initDeuterium(teilchen,nuc,eventNummer,keepNumber) PURPOSE. Represents nucleus nuc in phase space by testparticles which are stored in vector teilchen. The ordering in the vector teilchen is choosen to be random. The nucleus must be Deuterium. NOTES. ...
Read the excellent book called "Dark Sun" by Richard Rhodes, early tests done by Edward Teller, clearly used such techniques for the instrumentation of the devices and I knew a man here locally who personally handled the Liquid deuterium at Enewetok Atoll in the South Pacific.He told me when they set this device off, their ship was over thirty miles away, thats well over the horizon, and they could nt even see the Atoll, and the flash was just astounding. The back reflection of the blast off the atmoshere was beyond their expectations. Just about any radiation I can think of can be wave guided. All the way from the infrared end of the spectrum though microwaves to visible, up to x rays and gamma rays. Of course the wave guides went up with the devices. The first test shot device weighed in at 60 tons, so it was not a practicle device for military purposes ...
Read the excellent book called "Dark Sun" by Richard Rhodes, early tests done by Edward Teller, clearly used such techniques for the instrumentation of the devices and I knew a man here locally who personally handled the Liquid deuterium at Enewetok Atoll in the South Pacific.He told me when they set this device off, their ship was over thirty miles away, thats well over the horizon, and they could nt even see the Atoll, and the flash was just astounding. The back reflection of the blast off the atmoshere was beyond their expectations. Just about any radiation I can think of can be wave guided. All the way from the infrared end of the spectrum though microwaves to visible, up to x rays and gamma rays. Of course the wave guides went up with the devices. The first test shot device weighed in at 60 tons, so it was not a practicle device for military purposes ...
Supplier pricing and chemical structure of high purity D-[1-13C;1-2H]mannose a stable Carbon-13 and deuterium (2H) labeled isotope from Omicron Biochemicals, Inc.
Deuterium is an isotope of Hydrogen containing 1 neutron, 1 proton, and 1 electron. This isotope of hydrogen is an essential part of Nuclear Fusion. This article is a stub, and may need more information. You can help Space Wiki by expanding it.
explains, the electric field "strips electrons from the gas molecules and accelerates them to huge energies. The electrons then collide with stationary nuclei in the crystal and generate X-rays.". Putterman realised that the electric fields generated were sufficiently strong to spark nuclear fusion in deuterium - a "mind-boggling" 107 electronvolts as the excited boffin put it.. The recipe for UCLA nuclear fusion is as follows: Bathe lithium tantalate in deuterium gas. Cool to -33°C. Heat to 7°C over three-and-a-half minutes. Wait for electric field to "accelerate deuterium nuclei over a distance of 1 centimetre to energies in excess of 100 kiloelectronvolts". Watch as nuclei then collide and fuse with deuterium nuclei that had "permeated the surface of the crystal lattice".. And, if you get your recipe right, you should cook up "400 times more neutrons than found in background measurements".. Sounds good, but this represents a few hundred neutrons per second - way short of the millions of ...
Preventa-105 reduced deuterium 1,5l sparkling water, Preventa 105 1,5l csökkentett deutériumtartalmú szénsavas víz A Preventa®-105 csökkentett deutériumtartalmú ivóvíz betegek esetében a hagyományos terápiák mellett kiegészítő jelleggel alkalmazható. A kúra időtartama alatt egyéb folyadékok fogyasztása csak korlátozott mennyiségben javasolt. A napi mennyiséget (általában 1,5-2 liter) a nap folyamán 1-2 dl-es adagokra elosztva ajánlott elfogyasztani. 1 zsugor = 6db, VízBolt Webáruház
GODDARD HIGH-RESOLUTION SPECTROGRAPH OBSERVATIONS OF THE LOCAL INTERSTELLAR-MEDIUM AND THE DEUTERIUM HYDROGEN RATIO ALONG THE LINE OF SIGHT TOWARD CAPELLA Journal Article ...
Deuterium lamps for HPLC detectors and UV spectrophotometers. D2 lamps for Agilent, Beckman, Hitachi, Jasco, Knauer, Nicolet, Perkin-Elmer, Shimadzu, Unicam, Varian, Waters, etc.
Taking advantage of the fact that the Vostok deuterium (δD) record now covers almost two entire climatic cycles, we have applied the orbital tuning ap
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Dear Friends, Deuterium modifications : Version 11.01.28.159 1. Fixed minor bugs in null move pruning conditions. 2. Fixed minor bug in null move pruning verifi
About a single C-C bond results in a large bend in the chain. Lower down the chain, lateral displacements resulting from rotations about single C-C bonds are very much smaller, and, therefore, steric restrictions on motion become less important. The order parameter profile for the palmitoyl chain in (C16 0, C18 1)PC is very similar to that observed in di(C16 0)PC, but with order being slightly higher in bilayers of di(C16 0)PC than in bilayers of (C16 0,C18 1)PC, suggesting that introduction of.... ...
Focuses on measurements and calculations of isotope effects in chemical reactions and photodissociation. Covers a variety of processes, ranging from the very simple (atom-diatom reactions) to the complex (multiligand coordination compounds) and includes both neutral and ionic species. Examines a variety of applications, including those to astrophysical, planetary, and atmospheric science. Both light- and heavy-atom isotope effects are covered.
Concert Pharmaceuticals is replacing specific hydrogen atoms with deuterium atoms in clinically-validated drugs to develop differentiated new chemical entities
Barney, Jmol wasnt reading that column; it is now (11.3.50), so look for an update. Ive registered C-11 as slightly ligher in color than C-12. The way you select these is with an underscore ahead of the isotope number: select _11C select _13C For deuterium and tritium you can also use: select deuterium select _2H select D select trititum select _3H select T And you can color the elements this way to your liking, as well: color _11C green Bob Hanson Barny Shergold wrote: ,Hi, , ,Im new to the mailing list and I would really appreciate some help. My ,client uses a chemical that has many carbon atoms in it and one of them ,is actually Carbon-11. When I use and SDF file (show below) it models ,all the carbon atoms the same. Is there any way that Jmol can show an ,isotope? I just need that one Carbon atom to look a little different. , ,If you notice the 6th Carbon atom down it has a -1 next in the 5th ,column, this is the carbon atom in question and I assume the -1 is to ,indicate it is Carbon-11 ...
When analyzing deuterium in pharmaceuticals, we find that some drugs have one or more of the hydrogen atoms in the molecule replaced by deuterium.
Free Essay: Deuterium-Tritium Fusion Abstract The energy crisis is upon us. Fossil fuels are expected to be totally depleted within the next ten to fifty...
Seriously though. My weapons training showed that the critical mass required for an A bomb is more than what you stated. Yes I know that breeders have not worked out so far. I dont see why they couldnt be achieved by renewed engineering efforts ...
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Lamps provide the best wavelength coverage across the working range of the spectrometer for consistently high performance. All lamps are pre-aligned and can be easily changed by the user. Our extensive quality control and inspection process demands the very best quality sources to provide high sensitivity and stability for yourkey measurements.
Antall nedlastinger er summen av alle nedlastinger av alle fulltekster. Det kan for eksempel være tidligere versjoner som er ikke lenger ...
Scientists have found a new method to strategically add deuterium to benzene, an aromatic compound commonly found in crude oil. When applied to the active ingredient of drugs to incorporate deuterium, it could dramatically improve the drugs efficacy and safety and even introduce new medicines. ...
Please note, you must also purchase a cylinder with this item, US or European connection are available. There is an additional cost for the cylinder.. ...
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Deuterium nuclear magnetic resonance (2H-NMR) was used to investigate the structure and dynamics of the sn-2 hydrocarbon chain of semi-synthetical choline and ethanolamine plasmalogen in bilayers containing 0, 30, and 50 mol% cholesterol. The deuterium NMR spectra of the choline plasmalogen yielded well-resolved quadrupolar splittings which could be assigned to the corresponding hydrocarbon chain deuterons. The sn-2 acyl chain was found to adopt a similar conformation as observed in the corresponding diacyl phospholipid, however, the flexibility at the level of the C-2 methylene segment of the plasmalogen was increased. Deuterium NMR spectra of bilayers composed of the ethanolamine plasmalogen yielded quadrupolar splittings of the C-2 segment much larger than those of the corresponding diacyl lipids, suggesting that the sn-2 chain is oriented perpendicular to the membrane surface at all segments. Cholesterol increased the ordering of the choline plasmalogen acyl chain to the same extent as in ...
Noisy and overlapped mass spectrometry data hinders the sequence coverage that can be obtained from Hydrogen Deuterium exchange analysis, and places a limit on the complexity of the samples that can be studied by this technique. Advances in instrumentation have addressed these limits, but as the complexity of the biological samples under investigation increases, these problems are reencountered. Here we describe the use of binomial distribution fitting with asymmetric linear squares regression for calculating the accurate deuterium content for mass envelopes of low signal or that contain significant overlap. The approach is demonstrated with a test data set of HIV Env gp140 wherein inclusion of the new analysis regime resulted in obtaining exchange data for 42 additional peptides, improving the sequence coverage by 11%. At the same time, the precision of deuterium uptake measurements was improved for nearly every peptide examined. The improved processing algorithms also provide an efficient ...
TY - JOUR. T1 - Binding interface of cardiac potassium channel proteins identified by hydrogen deuterium exchange of synthetic peptides. AU - Chen, Jerri. AU - Angeletti, Ruth. AU - McDonald, Thomas V.. AU - Xiao, Hui. PY - 2012/5. Y1 - 2012/5. N2 - Three synthetic peptides, derived from the human potassium channel proteins Ether-a-go-go-related gene (HERG), KCNQ1, and KCNE1, were investigated by hydrogen deuterium exchange coupled with electrontransfer dissociation mass spectrometry at single residue resolution. Each amino acid residue in the first half of the HERG peptide incorporated deuterons with a higher rate than those in the second half of the peptide, consistent with the nuclear magnetic resonance structure of this peptide, with amino acids 1-10 being a flexible coil, whereas amino acids 11-24 are a stable amphipathic helix. The binding interface of KCNQ1 and KCNE1 was determined by comparing the difference of sequential fragment ions before and after binding. The residues determined to ...