Search results for "Reducing"
showing 10 items of 139 documents
Over-Oxidation as the Key Step in the Mechanism of the MoCl5-Mediated Dehydrogenative Coupling of Arenes.
2015
Molybdenum pentachloride is an unusually powerful reagent for the dehydrogenative coupling of arenes. Owing to the high reaction rate using MoCl5, several labile moieties are tolerated in this transformation. The mechanistic course of the reaction was controversially discussed although indications for a single electron transfer as the initial step were found recently. Herein, based on a combined study including synthetic investigations, electrochemical measurements, EPR spectroscopy, DFT calculations, and mass spectrometry, we deduct a highly consistent mechanistic scenario: MoCl5 acts as a one-electron oxidant in the absence of TiCl4 and as two-electron oxidant in the presence of TiCl4, bu…
FIA-fluorimetric determination of adrenaline in pharmaceutical formulations by oxidation with molecular oxygen
1998
The fluorimetric determination of adrenaline is carried out in a continuous-flow assembly and by means of the molecular dissolved oxygen. The sample solution merges with an NaOH stream, then the resulting mixture is heated at 73 °C and led to the flow-cell of the fluorimeter. The flow-assembly is very simple and the procedure is quick (107 samples h−1) reproducible (R.S.D. 0.6%), selective and suitable to be applied to determination of adrenaline in formulations. Calibrations graph are linear over the ranges 0.05–15 and 20–40 mgl−1.
Hemoglobin loaded polymeric nanoparticles: preparation and characterizations.
2011
In the present work polymeric nanoparticles based on Poly (maleic anhydride-alt-butyl vinyl ether) 5% grafted with m-PEG (2000) and 95% grafted with 2-methoxyethanol (VAM41-PEG) were loaded with human hemoglobin (Hb) and characterized from a physicochemical point of view. The assessment of structural and functional features of the loaded Hb was performed and the effect of the introduction of different reducing agents as aimed at minimizing Hb oxidation during the nanoparticles formulation process, was also investigated. Nanoparticles possessing an average diameter of 138 ± 10 nm and physicochemical features suitable for this kind of application were successfully obtained. Although the oxida…
A Randomized, Controlled Trial of 3.0 mg of Liraglutide in Weight Management.
2015
BACKGROUND: Obesity is a chronic disease with serious health consequences, but weight loss is difficult to maintain through lifestyle intervention alone. Liraglutide, a glucagon-like peptide-1 analogue, has been shown to have potential benefit for weight management at a once-daily dose of 3.0 mg, injected subcutaneously. METHODS: We conducted a 56-week, double-blind trial involving 3731 patients who did not have type 2 diabetes and who had a body-mass index (BMI; the weight in kilograms divided by the square of the height in meters) of at least 30 or a BMI of at least 27 if they had treated or untreated dyslipidemia or hypertension. We randomly assigned patients in a 2:1 ratio to receive on…
Biochemical analysis of class II antigens. Identification of a two- and a three-polypeptide chain complex of I-A locus equivalent molecules in the ra…
1983
The polypeptide chain composition of class II antigens from LEW rat spleen cells was studied utilizing cross-reactive mouse alloantiserum A. TH anti-A.TL (specificity anti-Iak) and the monoclonal antibodies MRC-OX6 and MRC-OX3 for immunoprecipitation. Two-dimensional gel mapping of A. TH anti-A. TL immunoprecipitates revealed that, as in the mouse, two groups of class II antigens exist corresponding to I-A and I-E locus equivalent structures. In the absence of reducing agents three monomeric chains α, 36 kDa (p36); γ, 33 kDa (p33); and β, 23 kDa (p23), were detected for I-A equivalent antigens, whereas I-E equivalent molecules separated into five monomeric chains: α, 37 kDa (p37); γ, 33 kDa…
New Strategy for the Stereoselective Synthesis of Fluorinated β-Amino Acids
2002
Racemic and chiral nonracemic alpha-substituted and alpha-unsubstituted beta-fluoroalkyl beta-amino acid derivatives 6 and 9 have been synthesized in two steps starting from fluorinated imidoyl chlorides 1 and ester enolates. This approach is based on the chemical reduction of previously obtained gamma-fluorinated beta-enamino esters 4 by using ZnI(2)/NaBH(4) in a nonchelated aprotic medium (dry CH(2)Cl(2)) as the reducing agent. A metal-chelated six-membered model has been suggested to explain the stereochemical outcome of the reduction reaction. The process takes place with high yields and with moderate to good diastereoselectivity. The best results related to diastereoselective reduction…
Optimization of iron speciation (soluble, ferrous and ferric) in beans, chickpeas and lentils
2001
Abstract A spectrophotometric method with bathophenanthroline for iron determination that makes it possible to differentiate between iron (II) and iron (III) in total soluble iron in legumes (beans, chickpeas and lentils) was optimized. Sample size, volumes of reducing agent and bathophenanthroline were selected. Matrix interferences made it necessary to apply the addition’s method. To check the quality of the method, linearity and precision (RSD%) were determined. A linear response between 0.1 and 1.8 μg Fe/ml in the assay and precision values ranging from 2.1 to 6 for instrumental precision, and from 1.6 to 1.7 and 2.7 to 9.1, for intra- and inter-day assays, respectively were obtained. T…
Determination of kinetic parameters of redox reactions using CE‐ICP‐MS: A case study for the reduction of Np(V) by hydroxylamine hydrochloride
2018
The rate constants k of the reduction of 5 × 10-5 M Np(V) to Np(IV) by hydroxylamine hydrochloride (HAHCl) in 1 M HCl have been determined by CE-ICP-MS in the temperature range of ϑ = 30-70°C and with varying concentrations of HAHCl from 1 to 7.2 M. The reaction was found to have (pseudo)first order kinetics with respect to HAHCl. The experimental results for k ranged from 0.0029(1) min-1 (ϑ = 40°C, c(HAHCl) = 3 M) to 0.039(7) min-1 (ϑ = 60°C, c(HAHCl) = 7.2 M). The activation energy of the reaction was determined as EA = (72 ± 10) kJ/mol. These results and a comparison with literature data show that the coupling of CE to ICP-MS provides a powerful analytical tool for the investigation of…
Synthesis and Stability Region of Stoichiometric Nanocrystalline Vanadium−Iron Spinel Powders
2000
Vanadium-iron spinels with nanometric sizes have been synthesized by a soft chemistry route. This way of elaboration consists of a coprecipitation followed by thermal treatments at low temperatures. The last thermal annealing is performed under a reducing atmosphere in order to obtain the exact oxygen stoichiometry (four oxygen atoms for three metal atoms in AB 2 O 4 ). Because of the low temperatures used, very low oxygen partial pressures (between 10 -20 and 10 -30 Pa) have to be applied. For this purpose, a reducing setup has been used. It consists of H 2 /N 2 /H 2 O gas mixtures, creating a reducing atmosphere with low oxygen partial pressure. This atmosphere can be applied to a sample …
Effect of a 3-week body mass reduction program on body composition, muscle function and motor performance in pubertal obese boys and girls
2005
The aim of this study was to investigate the effects of a multidisciplinary body mass reduction (BMR) program on body composition, muscle function and motor performance in 50 obese [mean body mass index (BMI): 35.9+/-5.8 kg/m2] boys and girls aged 12-17 yr (Tanner stage III, IV and V). The hospital-based BMR program combined an energy-restricted diet (1400-1600 kcal), nutritional education, psychological counselling and moderate physical activity (45-60 min/ session; 5 sessions/week; 60-80% of the maximal heart rate) during a 3-week period. Fat mass, fat-free mass, maximal power during jumping and stair climbing as well as maximal strength of the upper and lower limb muscles were quantified…