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131.
J. Legrand 《Canadian Metallurgical Quarterly》2002,128(11):1027-1031
Experimental data of pressure drop in flow through crushed rocks are reanalyzed with the capillary model in comparison with a model based on the square root of permeability as characteristic length. The capillary model is described by two parameters: the pore diameter and the tortuosity. The comparison leads to relationships between the structural parameters, Reynolds number, and friction factor of each model. The interest of the capillary model is that a single equation can predict all the experimental data expressed in terms of a pore friction factor as a function of pore Reynolds number. The equation, which is the sum of a viscous term and an inertial one, is valid for the whole Reynolds number domain. The equation can be used for the determination of the limits of the Darcy and turbulent flow regimes. According to the criterion used to neglect the viscous or the inertial term, the flow regimes limits can be expressed by a simple numerical value. 相似文献
132.
Dihydroceramide Δ4-desaturase 1 (DES1) catalyzes the last step of the de novo ceramide biosynthesis, which consists of the
introduction of a trans Δ4-double bond in the carbon chain of the dihydroceramide. It was previously observed that myristic acid binds DES1 through
N-myristoylation. This N-terminal modification significantly increased the activity of the recombinant DES1 in COS-7 cells
and targeted part of the enzyme initially present in the endoplasmic reticulum to the mitochondrial outer membrane, leading
to an increase in ceramide levels. Since these results were obtained in a recombinant COS-7 cell model with high expression
of rat DES1, the purpose of the present study was to investigate if the native DES1 enzyme was really upregulated by its N-myristoylation
in cultured rat hepatocytes. We first showed that DES1 was the main dihydroceramide desaturase isoform expressed in rat hepatocytes.
In this model, the wild-type myristoylable recombinant form of rat DES1 was found in both the endoplasmic reticulum and the
mitochondria whereas the mutated non-myristoylable recombinant form (N-terminal glycine replaced by an alanine) was almost
exclusively localized in the endoplasmic reticulum, which evidenced the importance of the myristoylation. Then, we showed
that compared to other fatty acids, myristic acid was the only one to increase native DES1 activity, in both total cell lysates
and mitochondrial fractions. The myristic acid-associated increase in DES1 activity was not linked to elevated mRNA or protein
expression but more likely to its N-terminal myristoylation. Finally, the myristic acid-associated increase in DES1 activity
slightly enhanced the number of apoptotic cells. 相似文献
133.
Sworowski M. Neuilly F. Legrand B. Summanwar A. Philippe P. Buchaillot L. 《Electron Device Letters, IEEE》2010,31(1):23-25
A new approach for the fabrication of large contour-mode single-crystal silicon resonators has been demonstrated without the use of SOI substrates. Twenty-four-megahertz disk resonators have been built thanks to industrial facilities dedicated to the integration of passive components on silicon and exhibit a good compromise between the quality factor higher than 50 000 and the motional resistance of a few kiloohms. 相似文献
134.
Tobias E.C. Price David M. Grant Vincent Legrand Gavin S. Walker 《International Journal of Hydrogen Energy》2010
In situ neutron diffraction was undertaken on stoichiometric 2LiBD4 : MgD2 and non-stoichiometric 0.3LiBD4:MgD2 with both ratios decomposed under 1 bar deuterium and under dynamic vacuum. The subsequent cycling behaviour under 100 bar D2 at 400 °C was investigated in situ. Analysis of the uptake through formation of deuterided products showed fast kinetics for the magnesium rich system, 0.3:1, with 90% deuteriding occurring within 10 min. This compares to only 60% deuteriding for the 2:1 sample after 4 h under similar conditions. These results demonstrate the strong influence of stoichiometry in the cycling kinetics compared to decomposition conditions, although the later determines the phase progression. 相似文献
135.
Baginsky S 《Mass spectrometry reviews》2009,28(1):93-120
Proteomics is an essential source of information about biological systems because it generates knowledge about the concentrations, interactions, functions, and catalytic activities of proteins, which are the major structural and functional determinants of cells. In the last few years significant technology development has taken place both at the level of data analysis software and mass spectrometry hardware. Conceptual progress in proteomics has made possible the analysis of entire proteomes at previously unprecedented density and accuracy. New concepts have emerged that comprise quantitative analyses of full proteomes, database-independent protein identification strategies, targeted quantitative proteomics approaches with proteotypic peptides and the systematic analysis of an increasing number of posttranslational modifications at high temporal and spatial resolution. Although plant proteomics is making progress, there are still several analytical challenges that await experimental and conceptual solutions. With this review I will highlight the current status of plant proteomics and put it into the context of the aforementioned conceptual progress in the field, illustrate some of the plant-specific challenges and present my view on the great opportunities for plant systems biology offered by proteomics. 相似文献
136.
LiFePO4 thin films were grown on silicon (100) substrates by pulsed laser deposition using Traditional Geometry (TG) and Off-Axis Geometry (OAG) deposition chambers. We examined and compared the structure and composition of the so formed thin films. The nails observed on the OAG-film present an amorphous “body” and a crystallized “head”. The Fe/P ratio determined using energy dispersive spectrometry combined with high angle annular dark field images reveals a metallic iron heart surrounded by LiFePO4 shell. On the other hand, the protuberances on TG-film are pure iron. The focused ion beam prepared cross-section of the film suggests the presence of iron particles and iron dendritic like filaments inside the LiFePO4 layer. 相似文献
137.
Optimization of dry heat treatment of egg white in relation to foam and interfacial properties 总被引:1,自引:0,他引:1
The properties of foams processed with reconstituted egg white were investigated as a function of the denaturation undergone by the proteins during the pasteurization stage in dry state. Various time-temperature tables were applied on the original egg white powder, ranging from 1 to 7 days, and from 60 to 80 °C. Differential Scanning Calorimetry was used to determine the denaturation degree of each EWP induced by the dry heat treatment. The rheological properties of the interface, using the drop tensiometer method, were shown to be significantly affected by the denaturation and to be a relevant parameter for foamability, stability and foam texture. The bulk properties of the foams were interrelated with interfacial properties by using principal component analysis (PCA) and cluster analysis (HCA). The resulting classification of the heat treatments reveals that mild treatment offers a good compromise between the heating cost and the functional properties of the foams. 相似文献
138.
Effect of proteins on the formation of starch–lipid complexes during extrusion cooking of wheat flour with the addition of oleic acid 下载免费PDF全文
Teresa De Pilli Jack Legrand Antonio Derossi Carla Severini 《International Journal of Food Science & Technology》2015,50(2):515-521
The formation of starch–lipid complexes plays an important role in extruded products. The effect of gluten proteins on thermal conditions at which the starch–lipid complexes formed during extrusion cooking of wheat flour with the addition of oleic acid was evaluated, considering wheat starch as a reference. The presence of gluten proteins in wheat flour extrudates brought about a reduction of the formation of starch–lipid complexes compared to blend of wheat starch and oleic acid extruded at the same operating conditions (melting enthalpy: 0.4 vs. 1.6 kJ kg?1). Moreover, the lubricant effect of oleic acid observed during extrusion of wheat starch (low values of specific mechanical energy and residence time) was not found during extrusion of wheat flour with addition of oleic acid because of the interaction between gluten proteins and oleic acid. This research points out the importance of proteins on biopolymer modifications and their effect on extrudate quality. 相似文献
139.
140.
The authors re-emphasize that the sure diagnosis of carcinoma of the cervix depends on histology; having considered a series of 15,000 smears in an article on cytological screening for carcinoma of the cervix. They show that the main prop of this histological examination should definitely be conisation. They furthermore prepare an inventory of the different possible methods of treatment of intra-epithelial carcinoma, stating for each method the advantages and disadvantages of the method. Their attitude to treatment is conservative, and they believe that conisation in every case is sufficient when complete removal of the in situ lesion is carried out whatever the age of the patient is. They state the limits of this method and define clearly the contra-indications for such a scheme of treatment, which can only be carried out routinely with the absolutely necessary cooperation of a cytology laboratory and faultless histology. 相似文献