Search results for "HYDROXYLAMINE"
showing 10 items of 34 documents
Determination of mercury in rice by cold vapor atomic fluorescence spectrometry after microwave-assisted digestion.
2010
Abstract A cold vapor atomic fluorescence spectrometry method (CV-AFS) has been developed for the determination of Hg in rice samples at a few ng g−1 concentration level. The method is based on the previous digestion of samples in a microwave oven with HNO3 and H2O2 followed by dilution with water containing KBr/KBrO3 and hydroxylamine and reduction with SnCl2 in HCl using external calibration. The matrix interferences and the effect of nitrogen oxide vapors have been evaluated and the method validated using a certified reference material. The limit of detection of the method was 0.9 ng g−1 with a recovery percentage of 95 ± 4% at an added concentration of 5 ng g−1. The concentration level …
Amino acid substitutions enhancing thermostability of Bacillus polymyxa beta-glucosidase A
1996
Mutations enhancing the thermostability of β-glucosidase A of Bacillus polymyxa, a family 1 glycosyl hydrolase, have been obtained after hydroxylamine mutagenesis of a plasmid containing the bglA gene, transformation of Escherichia coli with the mutagenized plasmid, and identification of transformant colonies that showed β-glucosidase activity after a thermal treatment that inactivated the wild-type enzyme. Two additive mutations have been characterized that cause replacement of glutamate at position 96 by lysine and of methionine at position 416 by isoleucine respectively. The thermoresistant mutant enzymes showed increased resistance to other denaturing agents, such as pH and urea, while …
Metabolism of nilutamide in rat lung.
2005
Nilutamide is a non-steroidal anti-androgen drug proposed in the treatment of metastatic prostatic carcinoma. Its therapeutic effects are overshadowed by the occurrence of adverse reactions, mediated by mechanisms that remain elusive. To elucidate possible mechanisms for nilutamide toxicity, we investigated the metabolism of nilutamide in rat lung homogenates, in subcellular fractions and in freshly isolated cells. In whole lung homogenates, the nitro group of nilutamide was reduced to the amine and hydroxylamine moieties. These conversions occurred exclusively in the absence of dioxygen, were increased by the addition of FMN, FAD, or NADPH. Reductive metabolism of nilutamide to the amine a…
A comprehensive integrated membrane bioreactor model for greenhouse gas emissions
2018
Abstract A comprehensive integrated membrane bioreactor (MBR) model for wastewater treatment is here proposed. The model quantifies the main biological and physical processes. The model describes the biological removal of organic matter, nitrogen and phosphorus including greenhouse gases (carbon dioxide, CO 2 and nitrous oxide, N 2 O). The model takes into account the following main innovative aspects jointly: i. Two-step nitrification process; ii. N 2 O formation due to ammonia-oxidizing bacteria as a product of the hydroxylamine oxidation (NH 2 OH) and of the nitrite (NO 2 − ) reduction; iii. Soluble microbial product (SMP) formation/degradation due to microbial growth and endogenous resp…
CCDC 1970751: Experimental Crystal Structure Determination
2020
Related Article: Jamal Lasri, Saied M. Soliman, Sobhy E. Elsilk, Matti Haukka, Ayman El-Faham|2020|J.Mol.Struct.|1207|127848|doi:10.1016/j.molstruc.2020.127848
Synthesis of fluorinated 1,2,4-oxadiazin-6-ones through ANRORC rearrangement of 1,2,4-oxadiazoles
2009
Abstract The reaction of 3-ethoxycarbonyl-5-perfluoroalkyl-1,2,4-oxadiazoles with hydroxylamines has been investigated, evidencing the possibility of competitive reaction paths. Nucleophilic addition of hydroxylamine to the electrophilic C(5) of the 1,2,4-oxadiazole ring, followed by ring-opening and ring-closure with enlargement, leads to high yield and in very mild experimental conditions to the formation of 5-hydroxyamino-3-perfluoroalkyl-6 H -1,2,4-oxadiazin-6-ones, one of these presenting water gelation ability. In turn, reactions with N -methylhydroxylamine lead the exclusive formation of 4-perfluoroacylamino-2-methyl-2 H -1,2,5-oxadiazol-3-ones through the well known Boulton–Katritzk…
Behavioural studies on rats injected with l-cycloserine and other compounds
1964
l-cycloserine, a cyclic derivative of O-substituted hydroxylamine, causes the suppression of the conditioned avoidance reaction in the rat. The subsequent injection of equimolar amounts of pyridoxine hydrochloride is responsible for a complete reversal of this suppression. The suppression of the conditioned response is not observed with the d-isomer of cycloserine. Isoniazid is a strong antagonist of l-cycoserine. Changes in the brain level of GABA under several conditions are described. These changes suggest though do not establish a relationship between the block of the conditioned response and the elevation of the aminoacid above its physiological concentration.
Polymere acroleine. III. Mittteilung. Oximierung und quantitative Bestimmung der Aldehydgruppen
1956
Die Oximierung von Disacryl wird beschrieben. Ferner werden Bedingungen fur eine quantitative Bestimmung von Aldehydgruppen in polymeren Acroleinen mitgeteilt. Es wird festgestellt, das Disacryl und ein durch Redox-Polymerisation gewonnenes Polyacrolein etwa 65% reaktionsfahige Aldehydgruppen enthalten. Bei Polyacroleinen, die mittels Borfluorid-Atherat oder Kaliumcarbonat gewonnen wurden, betragt der Umsatz mit Hydroxylamin nur etwa 20% d. Th. The oximation reaction of disacryl is described. The conditions of a quantitative determination of aldehyde function in polymeric acroleins have been investigated. It has been shown, that disacryl and an other polyacrolein, prepared by a redox-polyme…
CCDC 864758: Experimental Crystal Structure Determination
2021
Related Article: Lorena Martínez, Nicolás Veiga, Carla Bazzicalupi, Antonio Bianchi, Francesc Lloret, Carlos Kremer, Raúl Chiozzone|2021|Polyhedron|208|115406|doi:10.1016/j.poly.2021.115406
REDUCTION OF NILUTAMIDE BY NO SYNTHASES : IMPLICATIONS FOR THE ADVERSE EFFECTS OF THIS NITROAROMATIC ANTIANDROGEN DRUG
2003
Nitric oxide synthases (NOSs) are flavohemeproteins that catalyze the oxidation of l-arginine to l-citrulline with formation of the widespread signal molecule NO. Beside their fundamental role in NO biosynthesis, these enzymes are also involved in the formation of reactive oxygen species and in the interactions with some xenobiotic compounds. Nilutamide is a nonsteroidal antiandrogen that behaves as a competitive antagonist of the androgen receptors and is proposed in the treatment of metastatic prostatic carcinoma. However, therapeutic effects of nilutamide are overshadowed by the occurrence of several adverse reactions mediated by toxic mechanism(s), which remain(s) poorly investigated. H…