نتایج جستجو برای: bromine
تعداد نتایج: 2325 فیلتر نتایج به سال:
AIMS To examine the possible consequences of high plasma concentrations of bromine on thyroid hormone. METHODS Bromine was measured by inductively coupled plasma mass spectrometry in the plasma of 799 patients consulting for thyroid disorders. Because the mean (SD) bromine concentration in the plasma of healthy subjects is 4 (1) mg/l, concentrations above 6 mg/l were regarded as outside the n...
ZONDEK AND BIER [1932; 1933] have pointed out that in certain cases of mental disorder (particularly of the manic-depressive type) the blood-bromine is usually considerably lower than normal. Unfortunately they used a method of bromine estimation which is subject to severe criticism and hence, although their conclusions may be correct, the work requires repetition with a sound method of bromine...
A facile, efficient, simple, environmentally safe, regioselective, controllable and economical method for the oxybromination of aromatic compounds using NH4Br-Br2 system. The electrophilic substitution of bromine generated in situ from NH4Br as a bromine source and molecular bromine as an oxidant.
Background: Possibility to trace-label albumin with isotopes results in information concerning its synthesis, breakdown, and distribution in the intra and extra cellular spaces. The iodination of albumin is a widespread procedure used in scientific studies. Bromine not only is more reactive and less expensive than iodine, but bonds more easily with many elements. Therefore, it could be a suitab...
Sudden depletions of tropospheric ozone during spring were reported from the Arctic and also from Antarctic coastal sites. Field studies showed that those depletion events are caused by reactive halogen species, especially bromine compounds. However the source and seasonal variation of reactive halogen species is still not completely un-5 derstood. There are several indications that the halogen...
a spectrophotometric study concerning the interactoin between iodine and bromine with tetrabutylammonium iodide (tbai), tetrabutyl- ammonium bromide (tbabr) and cryptand 222 (c222) has been performed in dichloromethane solution at 25°c. the results are indicative of the formation of tba+x3- and c222x+x3- through equilibrium and formation of c222x+x- through nonequilibrium reactions. the stab...
Sudden depletions of tropospheric ozone during spring were reported from the Arctic and also from Antarctic coastal sites. Field studies showed that those depletion events are caused by reactive halogen species, especially bromine compounds. However the source and seasonal variation of reactive halogen species is still not completely understood. There are several indications that the halogen mo...
Very short-lived brominated substances (VSLBr) are an important source of stratospheric bromine, an effective ozone destruction catalyst. However, the accurate estimation of the organic and inorganic partitioning of bromine and the input to the stratosphere remains uncertain. Here, we report near-tropopause measurements of organic brominated substances found over the tropical Pacific during the...
A new, high yielding method for the preparation of vasicinone (7) is described. Reaction of 2-nitrobenzoic acid with N, N¢-carbonyldiimidazole followed by 2-pyrrolidinone gave 1-(2-nitrobenzoyl)pyrrolidine-2-one (3). Reduction of the latter with 10% Pd-C afforded deoxyvasicinone (4). Reaction of deoxyvasicinone (4) with bromine yielded monobromo-deoxyvasicinone (5). Exchange of bro...
Bromine may act as a catalyst for recombination of ozone and could be more efficient than either nitric oxide or chlorine. The lower atmosphere contains small concentrations of gaseous bromine produced in part by marine activity, in part by volatilization of particulate material released during the combustion of leaded gasoline, with an additional contribution due to the use of methyl bromide a...
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