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排序方式: 共有172条查询结果,搜索用时 265 毫秒
71.
Song-Hai Chai Jane Y. Howe Xiqing Wang Michelle Kidder Viviane Schwartz Melissa L. Golden Steven H. Overbury Sheng Dai De-en Jiang 《Carbon》2012,50(4):1574-1582
Graphitic mesoporous carbon (GMC), prepared through high-temperature graphitization of soft-templated amorphous mesoporous carbon (AMC), was used as the support for Mn, Li, and Fe triple-promoted Rh catalysts for CO hydrogenation to ethanol. The use of GMC results in C2H5OH selectivity and formation rate comparable to nonporous SiO2 support along with a significant inhibition on the formation of undesired CH4 and light hydrocarbons at the expense of appreciable amounts of CO2 produced. The better catalytic performance of promoted-Rh/GMC than those supported on other carbon allotropes (AMC and non-porous graphitic carbon black) seems to be associated with the specific graphitic structure and mesoporosity of GMC. The surface modification of GMC by wet oxidation leads to considerable increases in C2H5OH selectivity and formation rate. The modified GMC as a support shows substantially greater CO2-free selectivity for C2H5OH than the SiO2. 相似文献
72.
Jean-Baptiste Cambon Florence AnsartJean-Pierre Bonino Viviane Turq 《Progress in Organic Coatings》2012
Stainless steels are increasingly used in the aeronautics field for the manufacture of structural parts. One of them, the X13VD martensitic stainless steel (X12CrNiMoV12-3), known for its good mechanical properties, has a poor corrosion resistance in confined or severe environments. In the past years, Cr(VI) based pre-treatments have been currently used for corrosion protection of different metals, however, they are toxic and due to environmental regulations, they will be definitely banned in a near future. Alternatives to replace Cr(VI) show advantages and drawbacks considering key properties such as: corrosion resistance, adhesion of coatings, fatigue resistance, durability and reliability. However, some of their possible alternatives show high potential. 相似文献
73.
Joyce Maria Gomes da Costa Eric Keven Silva Ariel Antonio Campos Toledo Hijo Viviane Machado Azevedo Soraia Vilela Borges 《Drying Technology》2013,31(3):346-354
The effect of water content on the glass transition temperature of Swiss cheese bioaroma microencapsulated with a spray dryer was determined using differential scanning calorimetry (DSC) while mass loss was determined by thermogravimetric analysis (TGA). The sorption isotherm behavior was assessed at 15–45°C. Data were fitted with different sorption models. The bioaroma microparticles were produced via spray drying in a matrix with a 1:1 ratio (w/w) of maltodextrin 20DE and modified corn starch (Capsul). The isotherms displayed Type II behavior, and the best fit was obtained by the Guggenheim–Anderson–de Boer (GAB) model (coefficient of determination R² ≥ 0.98). The DSC analysis showed that the increased equilibrium moisture content caused a significant reduction in the Tg of the microparticles. The samples stored at intermediate humidity showed thermal stability and the samples with equilibrium moisture content of 17.92% showed a lower mass loss. 相似文献
74.
Gracieli DALLA NORA Solange Bosio TEDESCO Tamara PASTORI Viviane Dal-Souto FRESCURA Nerinéia Dalfollo RIBEIRO Haywood Dail LAUGHINGHOUSE IV Sidinei José LOPES Maria Teresa SCHIFINO-WITTMANN 《Biocell》2014,38(1):33-38
The aims of this study were to determine the meiotic behavior and to estimate pollen grains viability in bean (Phaseolus vulgaris L.) cultivars. Flower buds were collected during different developmental stages
of the Mesoamerican bean cultivars IAPAR 44, Guapo Brilhante, BRS Expedito, BRS Valente, Guateian 6662
and Pérola, and the Andean bean cultivar Iraí, grown in a greenhouse. The meiotic index was determined by
anther squashing of material fixed in absolute ethanol-glacial acetic acid (3:1) and stained with acetic orcein.
No meiotic abnormalities were observed and the meiotic indices were high for all cultivars, indicating that the
mismatch generated during crosses is not related to any meiotic changes. Estimation of pollen viability was made
by comparing acetic orcein staining vs. Alexander’s reactive: pollen viability was high in all cultivars with either
stain, but was significantly higher when using the acetic orcein stain (>99%). Though some cultivar showed a
significantly smaller pollen size, the range of variation among cultivars was low (means’ range 51-66 μm) 相似文献
75.
Regiane Victória de Barros Fernandes Eric Keven Silva Soraia Vilela Borges Cassiano Rodrigues de Oliveira Maria Irene Yoshida Yasmim Fernanda da Silva Eloá Lourenço do Carmo Viviane Machado Azevedo Diego Alvarenga Botrel 《Food and Bioprocess Technology》2017,10(1):115-130
The aim of this study was to evaluate the effects of the blending of whey protein isolate (WPI) with maltodextrin (MD) and inulin (IN) biopolymers as encapsulating matrices for spray-dried ginger essential oil. Encapsulation was performed by ultrasound-assisted emulsification and using spray drying, and the stability parameters of the emulsion (with or without ultrasound-assisted) were evaluated. The influence of these different wall material systems was investigated based on various functional properties of microparticles such as stability of the emulsion, encapsulation efficiency, reconstitution properties, chemical profile, microparticle stability, morphology, particle size distribution, and crystallinity. Higher viscosity values were obtained for the emulsions prepared with WPI and IN which had the apparent viscosity increased by the ultrasound-assisted emulsification process. Creaming index values indicated that ultrasound-assisted emulsions had higher stability. The composition of the wall materials did not affect the solubility and the moisture content of the particles. The wettability property of the powders was improved by the addition of IN. The lowest level of water adsorption under conditions of high relative humidity was also observed in microparticles containing IN. The partial replacement of WPI by MD significantly affected the efficiency of encapsulation. Moreover, MD led to high thermal microparticle stability. Larger particles were observed in the powders prepared with WPI. The powders obtained from WPI, WPI:IN, and WPI:MD treatments exhibited amorphous structures and did not have any cracks on the surface. The findings of this study indicate that IN and MD together with WPI proved to be good alternative secondary wall materials for spray-dried ginger oil. 相似文献
76.
Torsten Hoffmann Jens-Ulrich Rahfeld Mathias Schenk Falk Ponath Koki Makioka Birgit Hutter-Paier Inge Lues Cynthia A. Lemere Stephan Schilling 《International journal of molecular sciences》2021,22(21)
Compelling evidence suggests that pyroglutamate-modified Aβ (pGlu3-Aβ; AβN3pG) peptides play a pivotal role in the development and progression of Alzheimer’s disease (AD). Approaches targeting pGlu3-Aβ by glutaminyl cyclase (QC) inhibition (Varoglutamstat) or monoclonal antibodies (Donanemab) are currently in clinical development. Here, we aimed at an assessment of combination therapy of Varoglutamstat (PQ912) and a pGlu3-Aβ-specific antibody (m6) in transgenic mice. Whereas the single treatments at subtherapeutic doses show moderate (16–41%) but statistically insignificant reduction of Aβ42 and pGlu-Aβ42 in mice brain, the combination of both treatments resulted in significant reductions of Aβ by 45–65%. Evaluation of these data using the Bliss independence model revealed a combination index of ≈1, which is indicative for an additive effect of the compounds. The data are interpreted in terms of different pathways, in which the two drugs act. While PQ912 prevents the formation of pGlu3-Aβ in different compartments, the antibody is able to clear existing pGlu3-Aβ deposits. The results suggest that combination of the small molecule Varoglutamstat and a pE3Aβ-directed monoclonal antibody may allow a reduction of the individual compound doses while maintaining the therapeutic effect. 相似文献
77.
Viviane Borne 《Bulletin of Engineering Geology and the Environment》1990,42(1):11-20
The EM 34-3 conductivity-meter measures an apparent resistivity of the earth through the modifications of an electromagnetic field energized by the transmitter coil. According to the intercoil spacing, the instrument gives different depths of exploration. The measures are ponctual along survey profiles or at points forming a regular grid, depending on the exploration problem to be solved. The results obtained with this method are profiles or maps of apparent resistivity at different depths of exploration which makes it possible to have measurements results ready for direct interpretation. Nevertheless a two layer earth model interpretation with the help of horizontal dipoles, allows to specify the earth structure: deposition in paleovalleys, cartography of grabens, etc. 相似文献
78.
M Uguccioni CR Mackay B Ochensberger P Loetscher S Rhis GJ LaRosa P Rao PD Ponath M Baggiolini CA Dahinden 《Canadian Metallurgical Quarterly》1997,100(5):1137-1143
Eosinophil leukocytes express high numbers of the chemokine receptor CCR3 which binds eotaxin, monocyte chemotactic protein (MCP)-4, and some other CC chemokines. In this paper we show that CCR3 is also highly expressed on human blood basophils, as indicated by Northern blotting and flow cytometry, and mediates mainly chemotaxis. Eotaxin and MCP-4 elicited basophil migration in vitro with similar efficacy as regulated upon activation normal T cells expressed and secreted (RANTES) and MCP-3. They also induced the release of histamine and leukotrienes in IL-3-primed basophils, but their efficacy was lower than that of MCP-1 and MCP-3, which were the most potent stimuli of exocytosis. Pretreatment of the basophils with a CCR3-blocking antibody abrogated the migration induced by eotaxin, RANTES, and by low to optimal concentrations of MCP-4, but decreased only minimally the response to MCP-3. The CCR3-blocking antibody also affected exocytosis: it abrogated histamine and leukotriene release induced by eotaxin, and partially inhibited the response to RANTES and MCP-4. In contrast, the antibody did not affect the responses induced by MCP-1, MCP-3, and macrophage inflammatory protein-1alpha, which may depend on CCR1 and CCR2, two additional receptors detected by Northern blotting with basophil RNA. This study demonstrates that CCR3 is the major receptor for eotaxin, RANTES, and MCP-4 in human basophils, and suggests that basophils and eosinophils, which are the characteristic effector cells of allergic inflammation, depend largely on CCR3 for migration towards different chemokines into inflamed tissues. 相似文献
79.
de O Figueiredo LJ Garrido FM Kunisawa VY Aboim CE Licks OB 《Journal of molecular graphics & modelling》2006,24(4):227-232
This work presents a chemometric classification for a set of phosphodiesterase 5 inhibitors, based on a pattern recognition method widely used in quantitative structure-activity (QSAR) studies, hierarchical cluster analysis (HCA) and principal component analysis (PCA), aiming to access the most relevant structural and physicochemical variables related to phosphodiesterase 5 inhibition and to quantify the similarity of the structures within the set of inhibitors. Our model is capable of classifying a test set of 26 known phosphodiesterase 5 inhibitors in terms of similarity, the results being consistent with published experimental data. 相似文献
80.
Viviane Torres da Silva 《Autonomous Agents and Multi-Agent Systems》2008,17(1):113-155
Open multi-agent systems composed of heterogeneous, autonomous and independently designed agents are usually governed by a
set of norms. The established norms regulate the behavior of the agents by pointing out their permissions, prohibitions and
obligations. This paper presents a normative language to specify norms and proposes the implementation of such norms by using
a rule-based system. The implementation is achieved by automatically transforming the specification of each norm of the system
into a set of rules used to govern the behavior of the agents according to the norm. The governance system is able to activate
and deactivate norms, to point out the norms violations and fulfillments and to inform about punishments and rewards. 相似文献