Search results for "kinetics"
showing 10 items of 2224 documents
An experimental and modelling study of the oxidation of 3-pentanol at high pressure
2018
International audience; High pressure oxidation of 3-pentanol is investigated in a jet-stirred reactor and in a shock tube. Experiments in the reactor were carried out at 10 atm, between 730 and 1180 K, for equivalence ratios of 0.35, 0.5, 1, 2, 4 and 1000 ppm fuel, at a constant residence time of 0.7 s. Reactant, product and intermediate species mole fractions were recorded using Fourier transform infrared spectroscopy (FTIR) and gas chromatography (GC). Ignition delay times were measured for 3-pentanol/O2 mixtures in argon in a shock tube at 20 and 40 bar, in a temperature range of 1000–1470 K and for equivalence ratios of 0.5, 1 and 2. The fuel did not show any low-temperature reactivity…
Effect of cropping cycles and repeated herbicide applications on the degradation of diclofop-methyl, bentazone, diuron, isoproturon and pendimethalin…
2002
A greenhouse study was conducted to investigate the ability of four crops (wheat, corn, oilseed rape and soybean) to influence the degradation of bentazone, diclofop-methyl, diuron, isoproturon and pendimethalin in soil. The present study showed that microbial biomass-carbon was significantly higher in planted soils than in bulk soil, especially with wheat and corn, after several cropping cycles. The biomass in corn and soybean planted soils was adversely affected by bentazone but recovered after three cropping cycles. In wheat-planted soils, diclofop-methyl application resulted in persistent increase of the amount of microbial biomass. Bentazone did not show accelerated degradation even af…
Modeling lead input and output in soils using lead isotopic geochemistry
2004
The aim of this study is to model downward migration of lead from the plow layer of an experimental site located in Versailles (about 15 km southwest of Paris, France). Since 1928, samples have been collected annually from the topsoil of three control plots maintained in bare fallow. Thirty samples from 10 different years were analyzed for their lead and scandium contents and lead isotopic compositions. The fluxes are simple because of the well-controlled experimental conditions in Versailles: only one output flux, described as a first-order differential function of the anthropogenic lead pool, was taken into account; the inputs were exclusively ascribed to atmospheric deposition. The combi…
Rapid odorant release in mammalian odour binding proteins facilitates their temporal coupling to odorant signals.
2010
; We have measured the effect of rat odorant-binding protein 1 on the rates of ligand uptake and liquid-to-air transfer rates with a set of defined odorous compounds. Comparison of observed rate constants (k(obs)) with data simulated over a wide range of different kinetic and thermodynamic regimes shows that the data do not agree with the previously held view of a slow off-rate regime (k(off) <0.0004 s(-1)). We propose that a rapid koff would be a necessary requirement for such a system, since slow odorant-release rates would result in significant decorrelation between the olfactory world and odour perception. (c) 2010 Elsevier Ltd. All rights reserved.
Impact of viable CD45 cells infused on lymphocyte subset recovery after unrelated cord blood transplantation in children
2010
International audience; We studied lymphocyte recovery in 88 children who consecutively underwent unrelated cord blood transplantation for malignant (n = 64) or nonmalignant (n = 24) diseases. All children but 3 received myeloablative conditioning regimens with pretransplant antithymocyte globulin. Median age was 5.6 years (0.1-18 years) and median follow-up was 40 months (10-136 months). The median dose of infused viable CD45(+) cells (vCD45) was 3.35 × 10(7)/kg with a ratio infused vCD45/collected total nucleated cell at 0.46. Immunologic endpoints were: time to achieve CD3(+) >500 and 1500/mm(3), CD4(+) >500/mm(3), CD8(+) >250/mm(3), CD19(+) >200/mm(3), natural killer >100/mm(3). These e…
Effect of culture parameters on the production of styrene (vinyl benzene) and 1-octene-3-ol by Penicillium caseicolum
1992
SummaryPenicillium caseicolum has been shown to completely synthesize styrene. A medium was developed to test the capacity of different strains for this synthesis. In a synthetic medium, styrene production began only after the glucose was entirely consumed. This production depended on storage temperature and occurred simultaneously with 1-octene-3-ol formation.
Cerebrospinal fluid pharmacokinetics of ceftaroline in neurosurgical patients with external ventricular drain
2018
International audience; Background: Due to its antibacterial properties ceftaroline could be attractive for the treatment of bacterial postneurosurgicalmeningitis. However only few data are available concerning its meningeal concentrations. The aim of this studywas to investigate ceftaroline cerebrospinal fluid (CSF) pharmacokinetics (PK) in intensive care unit (ICU) patients with anexternal ventricular drain (EVD).Materials/methods: Patients received a single 600 mg dose of ceftaroline as a one-hour intravenous infusion . Blood and CSFsamples were collected before and 0.5, 1, 3, 6, 12 and 24 hours after the end of the infusion. Concentrations were assayed inplasma and CSF by LC-MS/MS. A tw…
Engineering a Saccharomyces cerevisiae Wine Yeast That Exhibits Reduced Ethanol Production during Fermentation under Controlled Microoxygenation Cond…
2006
ABSTRACTWe recently showed that expressing an H2O-NADH oxidase inSaccharomyces cerevisiaedrastically reduces the intracellular NADH concentration and substantially alters the distribution of metabolic fluxes in the cell. Although the engineered strain produces a reduced amount of ethanol, a high level of acetaldehyde accumulates early in the process (1 g/liter), impairing growth and fermentation performance. To overcome these undesirable effects, we carried out a comprehensive analysis of the impact of oxygen on the metabolic network of the same NADH oxidase-expressing strain. While reducing the oxygen transfer rate led to a gradual recovery of the growth and fermentation performance, its i…
Combustion wave structure during the MoSi2 synthesis by Mechanically-Activated Self-propagating High-temperature Synthesis (MASHS): In situ time-reso…
2006
Abstract In situ synchrotron time-resolved X-ray diffraction experiments coupled with an infrared imaging camera have been used to reveal the combustion wave structure during the production of MoSi2 by Mechanically Activated Self-propagating High-temperature Synthesis (MASHS). The fast combustion front exhibits a form described as an ‘equilibrium structure’ where the chemical reaction is the sole major driving force. In the MASHS process, oxide-free interfaces between Mo and Si nanocrystallites enhance the reaction Mo+2Si→MoSi2. Exhaustive time-resolved investigations show a possible solid-state process in the first second of the reaction within the combustion front. If preheating is added,…
Study of parameters endogeneous and exogeneous to ordinary Portland ciment influencing hydration of its main phase : tricalcium silicate
2012
This work devoted to study various parameters influencing hydration of silicate phase main Ordinary Portland Cement (OPC) was performed at the Laboratoire Interdisciplinaire Carnot de Bourgogne (ICB). This study is part of the project "Crystal Growth Control" initiated by BASF in order to monitor and provide the best as possible the hydration of Ordinary Portland Cement. The dissolution of alite, like the pure C3S one, is fast in pure water. Speed decreases with deviation from equilibrium and the concentration of aluminates ions in solution. There is also an adsorption on the surface of the aluminum which is into the alite and released by dissolution. Germination and growth of C-S-H has bee…