(n.) An ultimate particle of matter not necessarily indivisible; a molecule.
(n.) A constituent particle of matter, or a molecule supposed to be made up of subordinate particles.
(n.) The smallest particle of matter that can enter into combination; one of the elementary constituents of a molecule.
(n.) Anything extremely small; a particle; a whit.
(v. t.) To reduce to atoms.
Example Sentences:
(1) It has been conformed that catalase from bovine liver eliminates only the pro R hydrogen atom from ethanol.
(2) The results demonstrated that K2PtCl4 was bound to a greater degree than CDDP in this system with 3-5 and 1-2 platinum atoms respectively, bound per transferrin molecule.
(3) Richard Bull Woodbridge, Suffolk • Why does Britain need Chinese money to build a new atomic generator ( Letters , 20 October)?
(4) The bond distances of Cu to Cl(1), Cl(2), N(3) and N(3') atoms are 2.299 (1), 2.267 (1), 1.985 (4) and 1.996 (3) A, respectively.
(5) The common atoms of the [3Fe-4S] and [4Fe-4S] cores agree within 0.1 A; the three common cysteinyl S gamma ligand atoms agree within 0.25 A.
(6) This result was confirmed by atomic absorption spectroscopy, which indicated a stoicheiometry for copper and manganese of approx.
(7) The inter-molecular similarity measure used is the number of atoms in the 3-D common substructure (CS) between the two molecules which are being compared.
(8) The risks are determined, mainly by expert committees, from the steadily growing information on exposed human populations, especially the survivors of the atomic bombs dropped in Japan in 1945.
(9) All N and O atoms except N(3) and O(4') participate in a three-dimensional hydrogen-bonding system.
(10) This suggestion is supported by EPR studies, which show that the iron atoms in Fe(III)L-globin are in two low electronic states.
(11) The molar refractivity has been shown to be a superior parameter for the description of the activity of sulphonamides than the sum of electronegativities of atoms making up a heterocyclic substituent in the sulphonamide molecule and molecular weight of the substituent.
(12) Binding to HSA occurs primarily with the imidazolidine and thiazolidine groups of levamisole as it has been demonstrated by selective changes in the relaxation times and the chemical shifts of the protons attached to the carbon atoms.
(13) Each repeat unit contains thirty amino acids and is thought to bind a zinc atom using two cysteines and two histidines as ligands.
(14) NADP+ bound at the C8 atom in the adenine moiety proved to be the most efficient ligand whereas that bound at the C3 atom of the ribose moiety was relatively inefficient.
(15) This structure is further characterized by approaches of both the carbonyl and the furan O atoms to ring H atoms with separations which are slightly less than the sum of the relevant van der Waals radii.
(16) The magnitude of improvement achieved is dependent upon field size, SSD, the atomic number of the foil material, and foil thickness.
(17) For the liver enzyme, the logarithm of the inhibition constant was linearly related to the number of carbon atoms in the saturated fatty acids whereas the muscle enzyme, which was generally more strongly inhibited, showed a nonlinear dependence.
(18) Results obtained from a such study are here compared with levels obtained from a comparative determination of the metals in the mosses by three other techniques: Differential pulse anodic stripping voltammetry (DPASV), Direct current plasma (atomic emission) spectroscopy (DCPS) and X-ray fluorescence (XRF) spectroscopy.
(19) It was hypothesized that the observed activity variation of the paracetamol analogues was based on the relative abilities of these compounds to undergo H atom loss at the phenolic oxygen, and on the relative stabilities of the resulting free-radical species.
(20) The resulting family of structures has a mean backbone rmsd of 0.63 A (N, C alpha, C', O atoms), excluding the segments containing residues 45-59 and 84-88.
Fluorine
Definition:
(n.) A non-metallic, gaseous element, strongly acid or negative, or associated with chlorine, bromine, and iodine, in the halogen group of which it is the first member. It always occurs combined, is very active chemically, and possesses such an avidity for most elements, and silicon especially, that it can neither be prepared nor kept in glass vessels. If set free it immediately attacks the containing material, so that it was not isolated until 1886. It is a pungent, corrosive, colorless gas. Symbol F. Atomic weight 19.
Example Sentences:
(1) Fluorination with [18F]acetylhypofluorite yields 6-[18F]fluoro-L-dopa with 95% radiochemical purity; fluorination of the same substrate with [18F]F2 yields a mixture of all three structural isomers in a ratio of 70:16:14 for 6-, 5-, and 2-fluoro compounds.
(2) Recent studies with fluorine-18 (F-18) fluorodeoxyglucose suggest inhomogeneity of myocardial glucose metabolism in the normal human heart, which may relate to substrate availability.
(3) In vitro sensitizing activities were correlated to the promotion efficiency of radiolytic hydroxylation of thymine to thymine glycol and to the one-electron reduction potential of a variety of fluorinated and non-fluorinated nitroazole derivatives.
(4) The new fluorinated adenine analog, fludarabine, has been tested for efficacy in many tumor types over the past ten years.
(5) The campaign’s focus was the damage to the ozone layer caused by fluorinated gases, such as HFCs.
(6) After administration of niflumic acid, flufenamic and antrafenine, the urinary elimination of ionized fluorine increase in all the subjects.
(7) The introduction of fluorines at C-24 and extension of the sterol side chain at C-26 and C-27 by methylene groups results in vitamin D analogues that have biological activity in vivo similar to those of the respective nonfluorinated natural sterols.
(8) Early prenatal suppression of the fetal adrenal cortex with fluorinated corticosteroids can prevent virilization of female fetuses with 21-hydroxylase deficiency.
(9) The fluorine modification of nitroazole sensitizers could enhance both the absolute activity and the tumor affinity.
(10) Haemophilus influenzae strains with varied ampicillin resistance and beta-lactamase production patterns were tested against three investigational fluorinated quinolones (CI-960, fleroxacin, temafloxacin) using Haemophilus Test Medium (HTM) and National Committee for Clinical Laboratory Standards (NCCLS) methods.
(11) It has been found that workers in factories who have not been considered as subjected to fluorine hazard and therefore have not been controlled had significantly elevated urinary fluoride levels.
(12) (19)F-Nuclear magnetic resonance studies of specifically fluorinated hemoglobin derivatives have been used to determine the apparent pK(a) of the histidine beta146 imidazole in deoxyhemoglobin.
(13) To measure [Ca2+]i, fluorine NMR spectra were acquired in a separate group of hearts loaded with the Ca2+ indicator 5F-BAPTA [5,5'-difluoro derivative of 1,2-bis-(o-aminophenoxy)ethane- N,N,N',N'-tetraacetic acid].
(14) This is due to the influence of the fluorine substituent(s) on the basicity of the amine function proximal to the fluoromethylene group, this effect being amplified by geminal disubstitution.
(15) In intact cells of all 5-FC-susceptible strains the metabolism of 5-FU progressed to the formation of other fluorinated derivatives which were visualized as a single, broad resonance band at a lower field with respect to 5-FC and 5-FU.
(16) A major advance in antimicrobial chemotherapy was the synthesis of newer quinolones containing at least 1 fluorine atom and a piperazinyl group.
(17) We studied the relationship between antitumor efficacy of UFT, which is a most widely used drug among fluorinated pyrimidines recently, and its effect on the content and the inhibition rate of thymidylate synthase (TS) in 15 human tumor xenografts derived from stomach, colon, breast and pancreatic cancer patients.
(18) Fluorine-19 nuclear magnetic resonance images of rabbit hearts have been obtained with the administration of a fluorinated contrast compound.
(19) 31P NMR measurements of the magnesium-dependent shift between alpha- and beta-phosphates of ATP demonstrate that there is no measurable lowering of Mgi during loading with fluorinated o-aminophenol-N,N,O-triacetate.
(20) Thus, for fluoroanilines with a fluorine substituent at the para position bioactivation to the reactive benzoquinoneimine can be a direct result of the cytochrome P-450 dependent conversion.