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21.
22.
Juan Matos Andreina Garcia Tulynan Cordero Jean-Marc Chovelon Corinne Ferronato 《Catalysis Letters》2009,130(3-4):568-574
The influence of surface pH of activated carbon on selectivity of TiO2 during the photooxidation of 4-chlorophenol on UV-irradiation was studied. Chlorine substitution by p-hydroxylation yielding hydroquinone in equilibrium with benzoquinone and o-hydroxylation to 4-chlorocathecol were detected as the main intermediates in the photooxidation of 4CP. Changes in surface pH of carbons from basic to closely neutral induce a remarkably increase in the production of 4-chlorocatechol by a factor of 22 on TiO2–AC in comparison of TiO2 alone. A mechanism of interaction between both solids is proposed to explain changes both in photoactivity and photoselectivity of TiO2. In conclusion, results showed that TiO2–AC can be used as an alternative green photocatalyst in organic synthesis. 相似文献
23.
Maud Bruneteau Florence Fournol Corinne Gandon Michel Becchi Véronique Pivot 《Lipids》1997,32(4):359-362
Several inositol sphingophospholipids (ISPL) were isolated from mycelia of Phytophthora parasitica Dastur, a phytopathogenic fungus of carnation. The ISPL structures were determined by fast atom bombardment. All ISPL consisted
of ceramides linked to inositol phosphate. We investigated the effect of growth conditions on the ISPL produced in four different
media that are commonly used for fungal cultures. We showed that P. parasitica Dastur synthesized four major classes of compounds with molecular weights of Mr=751, 807, 835, and 849 containing the 16:1 base and the 16:0 or 20:0 or 22:0 or 22h:1 N-acyl group. The relative abundance of the different ISPL is dependent on growth conditions.
This work is dedicated to the memory of Professor G. Michel. 相似文献
24.
Corinne Remy Denis Andrault Michel Madon 《Journal of the American Ceramic Society》1997,80(4):851-860
Energy-dispersive X-ray powder diffraction experiments have been investigated at high temperature and room pressure, and at high pressure and room temperature, starting from either γ- or β-Ca2 SiO4 . High-temperature studies were performed up to 1980 K, using a versatile heating cell. The high-temperature phase transformations previously described were reexamined. Volume and linear thermal expansions were measured for each Ca2 SiO4 polymorph, γ, β, α';L ,α';H , and α. Volume thermal expansion increases with increasing temperature except for α';H , whose thermal expansion tends to decrease at elevated temperature. High-pressure investigations were performed in the 0–15 GPa pressure range, using a diamond anvil cell, with silicon oil as the pressure-transmitting medium. The value of the room-pressure bulk modulus K0 , assuming a second-order BirchMurnaghan equation of state with K'0 = 4, is 140(8) GPa for γ-Ca2 SiO4 . The γ olivine form exhibits anisotropic compression, with the c axis as the most compressible. From such in situ high-pressure X-ray investigations, the γ-→Ca2 SiO4 phase transformation induced by cold compression is clearly evidenced and extends from 2 to about 5 GPa. 相似文献
25.
Young Richard A.; Marshall Sheila K.; Domene José F.; Graham Matthew; Logan Corinne; Zaidman-Zait Anat; Mart Amy; Lee Celine M. 《Canadian Metallurgical Quarterly》2008,55(3):297
This study determined how youth (ages 17-21) and their parents jointly constructed and acted on goals and strategies pertinent to the transition to adulthood. Twenty parent-youth dyads were followed over an 8-month period using the qualitative action-project method. Data included their joint conversations, video recall of internal processes, self-monitoring logs, and researcher telephone monitoring. Detailed and repeated analysis of elements, functional steps, and goals resulted in the identification of an explicit joint project for each dyad that the participants saw as pertinent to the transition to adulthood. These projects referred broadly to the youth development of identity and social inclusion in the adult world and included the specific projects of career promotion, governance transfer, and parent-youth relational processes. The findings illustrate the complexity of the transition-to-adulthood process as well as its joint construction by parent and youth. Implications for practice include identifying and following the joint parent-youth transition project. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
26.
Laurence Ponsonnet Mirela Boureanu Nicole Jaffrezic Ali Othmane Corinne Dorel Philippe Lejeune 《Materials science & engineering. C, Materials for biological applications》2008,28(5-6):896-900
The development of surface-associated layers of matrix-embedded microbial populations, called biofilms, is a serious problem in many medical and industrial settings. These contaminations are difficult to eradicate because of the high resistance level acquired by the cells in their particular environment. From the very beginning of the colonization process, modifications of gene expression are observed and could, at least partially, explain biofilm resistance. In order to develop anti-biofilm molecules and surface treatments, it is of pivotal importance to identify the physico-chemical parameters which activate the sensor systems of pioneering microbes when they come into contact with a surface. The aim of our study was to examine the pH variations in the local micro-environment created between the cell layer and the surface after bacteria adhesion. Using an ion-sensitive field effect transistor (ISFET), as a substratum, colonized by a curli hyperproducing strain known to form biofilms, we observed that the evolution of the pH change was significantly different in the micro-compartment in contact with the electrochemical sensor compared to that within the liquid phase. 相似文献
27.
Corinne Berland Jean-François Bercher Olivier Venard 《Analog Integrated Circuits and Signal Processing》2010,65(1):151-156
Linear amplification with Nonlinear Component (LINC) transmitter architecture is an efficient solution for high efficiency
amplification of signals. Nonetheless, this solution suffers both from gain impairment and delay mismatch between the two
signal paths. Indeed, a mismatch in propagation time between the paths degrades the quality of the transmit signal but also
disrupts the convergence of the gain correction algorithm resulting in a degradation of its performance. In this paper, we
present an adaptive algorithm based on a gradient descent formulation for the identification and correction of these delays.
We also demonstrate its effectiveness when applied prior to the gain adjustment procedure. The identification approach is
preferred here, to ensure monitoring facilities. 相似文献
28.
Hydrogen fluoride (HF) is a known product from the combustion or detonation of explosives formulated with fluoropolymer binder systems. This presents the user with elevated risk levels during unintended combustion events or detonations in confined situations. In an effort to remediate the production of HF, calcium disilicide (CaSi2) was added to explosive formulations and the amount of HF formed was monitored. Viton A/calcium disilicide mixtures were made and the thermal decomposition characteristics studied using thermal gravimetric/differential thermal analysis (TG/DTA). The activation energy ranged from 145–190 kJ mol−1, indicative of C F scission in the Viton A binder prior to calcium fluoride formation. An energetic formulation was prepared which consisted of approximately a 5/3 mass ratio of Viton A/CaSi2. Combustion calorimetry in oxygen and air, and subsequent analysis of the residues using X‐ray diffraction (XRD) showed evidence of calcium fluoride (CaF2) formation. The decrease in HF formation was determined by trapping off gases and subsequent analysis in anion exchange chromatography of combustion and detonation products. Upon introduction of calcium disilicide into the formulation, a small decrease in HF formation was observed along with appearance of calcium fluoride and free Si in the residue. Such products are consistent with the mechanism following a general decomposition path of 2F−+CaSi2→CaF2+2Si. Under detonation conditions, the decomposition path followed nearly the same route with a net ca. 30 % decrease in HF formation, but with a portion of the silicon oxidizing slightly further to SiO2. 相似文献
29.
Devins Gerald M.; Mandin Henry; Hons Ronald B.; Burgess Ellen D.; Klassen John; Taub Kenneth; Schorr S.; Letourneau P. K.; Buckle Sherry 《Canadian Metallurgical Quarterly》1990,9(2):117
Examined the impact of illness intrusiveness (ILI) on quality of life (QOL) in 99 patients with end-stage renal disease. Ss were interviewed twice, 6 wks apart, to determine differences in perceived ILI across treatment modalities, life domains, and time. Life domains were affected differentially across treatments. Perceived ILI correlated significantly with treatment time requirements, uremic symptoms, intercurrent nonrenal illnesses, fatigue, and difficulties in daily activities. Significant QOL differences emerged across treatment modalities for satisfaction/happiness and pessimism/illness related concerns but not for depression/distress. Perceived ILI correlated significantly with each of these QOL measures. Findings substantiate the construct of ILI as a mediator of the psychosocial impact of chronic, life-threatening illness. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
30.
Cloning and disruption of the yeast C-8 sterol isomerase gene 总被引:8,自引:0,他引:8
William H. Ashman Robert J. Barbuch Corinne E. Ulbright Harry W. Jarrett Martin Bard 《Lipids》1991,26(8):628-632
The yeastERG2 gene codes for the C-8 sterol isomerase, an enzyme required for the isomerization of the δ8 double bond to the δ7 position
in ergosterol biosynthesis. TheERG2 gene was cloned by complementation of a C-8 sterol isomerase mutant strain (erg2). The complementing region of DNA required to restore ergosterol synthesis toerg2 was limited to a 1.0 kbStuI-BglII fragment. In order to determine whether theERG2 gene was essential for yeast viability, aLEU2 gene was inserted into theNdeI site (made blunt) of this 1.0 kb fragment. Transformation of a wild type diploid strain with theERG2 substituted DNA resulted in the generation of viable haploids containing theerg2 null allele (erg2–4∶∶Leu2). These results suggest that the C-8 sterol isomerase activity is not essential for yeast cell viability. This disruption
represents the second ergosterol biosynthetic gene in the distal portion of the pathway to be disrupted without adversely
affecting cell viability.
Based on a paper presented at the Symposium on Plant and Fungal Sterols: Biosynthesis, Metabolism and Function, held at the
AOCS Annual Meeting, Baltimore, MD, April 1990. 相似文献