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排序方式: 共有316条查询结果,搜索用时 15 毫秒
21.
Fábio G. Melchiades Bruna T. Rego Silvia M. Higa Helton J. Alves Anselmo O. Boschi 《Journal of the European Ceramic Society》2010,30(12):2443-2449
Transparency is an extremely important optical property of several glazes used in the ceramic tile sector. The present work aimed to identify the causes of loss of transparency presented by some ceramic glazes composed of frits with chemical compositions typical of optically transparent glasses. After identifying the causes of low transparency presented by several ceramic glazes based on microstructural analyses, X-ray diffraction and scanning electron microscopy, attempts were made to increase the transparency of these glazes by altering their chemical compositions. The results suggest that the addition of alumina – through distinct mineral sources – may be an interesting alternative to prevent the crystallization of calcium silicates, which reduce the transparency of glazes used in the ceramic tile sector. 相似文献
22.
A novel comprehensive numerical study is presented for a better understanding of mass transfer in channel flows with catalytically active walls at moderate temperatures and surface reaction rates. Altogether, 18 different numerical models are compared, which represent mass transfer in single channels of a honeycomb-type automotive catalytic converter operated under direct oxidation conditions. Three different channel geometries have been investigated: circular cross-section, square cross-section, and square cross-section with rounded corners (fillets). 1D plug-flow, 2D boundary-layer and Navier–Stokes, and 3D Navier–Stokes equations are applied to model the reactor geometry. The diffusion limitation within the porous washcoat has been modeled by a simplified zero-dimensional effectiveness factor model as well as multidimensional reaction–diffusion models. Furthermore, simulations are also carried out for cases with instantaneous diffusion within the washcoat. All numerical models account for the coupled interactions of mass-transfer and heterogeneous chemistry within the channels. The chemical conversion of the pollutants on the platinum catalyst is described by an elementary-step-like heterogeneous reaction mechanism consisting of 74 reactions among 11 gas-phase species and 22 adsorbed surface species. The results of numerical simulations are compared with experimental data. 相似文献
23.
Bruna Panizzutti Chiara C. Bortolasci Briana Spolding Srisaiyini Kidnapillai Timothy Connor Mark F. Richardson Trang T. T. Truong Zoe S. J. Liu Gerwyn Morris Laura Gray Jee Hyun Kim Olivia M. Dean Michael Berk Ken Walder 《International journal of molecular sciences》2021,22(13)
Recent reports suggest a link between positive regulation of the Hippo pathway with bipolar disorder (BD), and the Hippo pathway is known to interact with multiple other signaling pathways previously associated with BD and other psychiatric disorders. In this study, neuronal-like NT2 cells were treated with amisulpride (10 µM), aripiprazole (0.1 µM), clozapine (10 µM), lamotrigine (50 µM), lithium (2.5 mM), quetiapine (50 µM), risperidone (0.1 µM), valproate (0.5 mM), or vehicle control for 24 h. Genome-wide mRNA expression was quantified and analyzed using gene set enrichment analysis (GSEA), with genes belonging to Hippo, Wnt, Notch, TGF- β, and Hedgehog retrieved from the KEGG database. Five of the eight drugs downregulated the genes of the Hippo pathway and modulated several genes involved in the interacting pathways. We speculate that the regulation of these genes, especially by aripiprazole, clozapine, and quetiapine, results in a reduction of MAPK and NFκB pro-inflammatory signaling through modulation of Hippo, Wnt, and TGF-β pathways. We also employed connectivity map analysis to identify compounds that act on these pathways in a similar manner to the known psychiatric drugs. Thirty-six compounds were identified. The presence of antidepressants and antipsychotics validates our approach and reveals possible new targets for drug repurposing. 相似文献
24.
Lucas Portela Oliveira Camila Cristina de Foggi Bruna Natália Alves da Silva Pimentel Marcelo Assis Juan Andrés Elson Longo Carlos Eduardo Vergani 《Ceramics International》2021,47(16):22604-22614
The present study reports for the first time the performance of silver phosphate (Ag3PO4) microcrystals as photocatalyst (degradation of Rodamine B-RhB) and antifungal agent (against Candida albicans–C. albicans) under visible-light irradiation (455 nm). Ag3PO4 microcrystals were synthesized by a simple co-precipitation (CP) method at room temperature. The structural and electronic properties of the as-synthetized Ag3PO4 have been investigated before and after 4 cycles of RhB degradation under visible light using X-ray diffraction (XRD), micro-Raman spectroscopy, UV–Vis spectrophotometer and field emission scanning electron microscopy (FE-SEM) images. The antifungal activity was analyzed in planktonic cells and 48h-biofilm of C. albicans by colony forming units (CFU) counting, confocal laser and FE-SE microscopies. Statistical analysis was carried out using SPSS software. Morphological and structural modifications of Ag3PO4 were observed upon recycling. After 4 recycles, the material maintained its photodegradation property; an eightfold increase in the efficiency of Ag3PO4 was observed in planktonic cells and a two fold increase in biofilm when irradiated under visible light. Thus, higher antifungal effectiveness against C. albicans was obtained when associated with visible-light irradiation. 相似文献
25.
A structuring process is developed which enables the fabrication of gold patterns by electroplating with a minimum linewidth of ? 0.3 μm. These patterns are used as mask patterns for X-ray lithography. They can be up to 1.6 μm thick. For this purpose, a resist pattern, which is generated by an electron beam, is transmitted to a multi-layer system by reactive ion-beam etching. The multi-layer system consists of a 2 μm thick polyimide layer, a 70 nm thick aluminum intermediate layer and a 30 nm thick gold passivation layer.With this process, X-ray masks with a polyimide membrane were produced and utilized for exposure to synchrotron radiation. 相似文献
26.
Aline Bruna da Silva Celio Wisniewski Jo?o Victor Almeida Esteves Rinaldo Gregorio 《Journal of Materials Science》2010,45(15):4206-4215
Poly(vinylidene fluoride), PVDF, samples containing exclusively the polar β phase were obtained by crystallization from N,N-dimethylformamide (DMF) solution at 60 °C and subsequent pressing. Some of these samples were uniaxially drawn at 120 °C
at draw ratio of 4, resulting in oriented films. Oriented and unoriented samples were characterized as to relative fraction
of β phase, degree of crystallinity and orientation by infrared spectroscopy (FTIR), differential scanning calorimetry (DSC),
and wide-angle X-ray diffraction (WAXD). The dependence on frequency of the real (
e\textr¢ \varepsilon_{\text{r}}^{\prime} ) and imaginary (
e\textr¢¢ \varepsilon_{\text{r}}^{\prime\prime} ) components of the relative permittivity of the samples was determined between 104 and 1.7 × 107 Hz. The coercive field and stable and metastable remanent ferroelectric polarization were determined from the hysteresis
loop obtained by the ramp voltage technique, described in detail in this work. The results allowed verification of the effect
of drawing on structure and of the resulting structure on the dielectric properties, remanent polarization, and coercive field
of β-PVDF. A possible effect of the crystal–amorphous interphase region on the metastable remanent polarization is suggested.
The results obtained with the oriented and unoriented samples were compared with those obtained for films commercialized by
Piezotech S.A. 相似文献
27.
Bruna JM Hierro EM de la Hoz L Mottram DS Fernández M Ordóñez JA 《International journal of food microbiology》2003,85(1-2):111-125
An atoxigenic strain of Penicillium camemberti was superficially inoculated on fermented sausages in an attempt to improve their sensory properties. The growth of this mould on the surface of the sausages resulted in an intense proteolysis and lipolysis, which caused an increase in the concentration of free amino acids, free fatty acids (FFA) and volatile compounds. Many of these were derived from amino acid catabolism and were responsible for the "ripened flavour", i.e. branched aldehydes and the corresponding alcohols, acids and esters. The development of the fungal mycelia on the surface of the sausages also protected lipids from oxidation, resulting in both lower 2-thiobarbituric acid (TBARS) values and lipid oxidation-derived compounds, such as aliphatic aldehydes and alcohols. The sensory analysis of superficially inoculated sausages showed clear improvements in odour and flavour and, as a consequence, in the overall quality of the sausages. Therefore, this strain is proposed as a potential starter culture for dry fermented sausage production. 相似文献
28.
Fábio M. DaMatta Adriana Grandis Bruna C. Arenque Marcos S. Buckeridge 《Food research international (Ottawa, Ont.)》2010,43(7):1814-1823
Carbon emissions related to human activities have been significantly contributing to the elevation of atmospheric [CO2] and temperature. More recently, carbon emissions have greatly accelerated, thus much stronger effects on crops are expected. Here, we revise literature data concerning the physiological effects of CO2 enrichment and temperature rise on crop species. We discuss the main advantages and limitations of the most used CO2-enrichment technologies, the Open-Top Chambers (OTCs) and the Free-Air Carbon Enrichment (FACE). Within the conditions expected for the next few years, the physiological responses of crops suggest that they will grow faster, with slight changes in development, such as flowering and fruiting, depending on the species. There is growing evidence suggesting that C3 crops are likely to produce more harvestable products and that both C3 and C4 crops are likely to use less water with rising atmospheric [CO2] in the absence of stressful conditions. However, the beneficial direct impact of elevated [CO2] on crop yield can be offset by other effects of climate change, such as elevated temperatures and altered patterns of precipitation. Changes in food quality in a warmer, high-CO2 world are to be expected, e.g., decreased protein and mineral nutrient concentrations, as well as altered lipid composition. We point out that studies related to changes in crop yield and food quality as a consequence of global climatic changes should be priority areas for further studies, particularly because they will be increasingly associated with food security. 相似文献
29.
Ingrid Lessa Leal Yasmin Carolino da Silva Rosa Josenai da Silva Penha Paulo Romano Cruz Correia Pollyana da Silva Melo Danilo Hansen Guimarães Josiane Dantas Viana Barbosa Janice Izabel Druzian Bruna Aparecida Souza Machado 《应用聚合物科学杂志》2019,136(43):48150
In this study, formulations of cassava starch and poly(butylene adipate-co-terephthalate) flexible films were developed, with glycerol, coconut nanocellulose, annatto, and citric acid in different concentrations, as well as the effectiveness of the selected materials in fresh-cut mangoes storage was evaluated. The tensile strength of the different formulations varied from 1.90 (E4) to 6.65 MPa (E3c), and the strain varied from 206.31 (E1c) to 278.41% (E8); this variation was dependent on the percentage of the polymer matrix incorporated. The aw values of the formulations ranged from 0.396 (E2) to 0.569 (E3c). The Formulations E4 and E7 (with additives) presented good properties and were selected to condition mangoes. The micrographs of these films showed regions of micropores that can facilitate the diffusion of water from the packaged product to the surface, allowing decreases in moisture and aw, which is associated with higher color maintenance during fruit storage. E7 presented better barrier properties than E4 (lower values of WVP and water solubility) which may have influenced in a positive way to maintain the stability of the package in the studied period. E7 can be considered as a viable alternative for minimally processed mango storage. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 48150. 相似文献
30.
Eva Hierro Juan A. Ordóñez José M. Bruna Carmen Pin Manuela Fernández Lorenzo de la Hoz 《European Food Research and Technology》2005,220(5-6):494-501
The effect of the inoculation of dry fermented sausage surface with an atoxigenic, proteolytic and lipolytic strain of Mucor racemosus, Penicillium aurantiogriseum and Penicillium camemberti on the volatile composition was studied. The analysis of the headspace volatile compounds using gas chromatography/mass spectrometry enabled the identification of 55 volatiles. The study showed that every mould species produced a different volatile profile which was also different from that of the control sausages. Compounds derived from amino acid catabolism, i.e. branched aldehydes and the corresponding alcohols, were produced in higher amounts in sausages inoculated with Penicillium spp. On the other hand, volatiles coming from the microbial esterification were related to sausages inoculated with M. racemosus. The development of the fungal mycelia on the sausage surface protected lipids from oxidation, thus giving rise to fewer lipid oxidation products in the inoculated sausages. 相似文献