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71.
72.
A rapid quenching apparatus employing a laser beam was developed to obtain the glassy state of oxides which have high melting temperatures. Using this apparatus, the glassy state in Ln-Ti-O, Ln-Nb-O and Ln-Ta-O (Ln=lanthanides) systems was investigated. The range of compositions which produced glasses and the crystallization process were studied in detail, and the metastable phases, which appear during the crystallization process, were examined by differential thermal and X-ray diffraction analysis.  相似文献   
73.
The mechanism of gap junction enhancer (PQ1) induced cytotoxicity is thought to be attributed to the change in connexin 43 (Cx43) expression; therefore, the effects of Cx43 modulation in cell survival were investigated in mammary carcinoma cells (FMC2u) derived from a malignant neoplasm of a female FVB/N-Tg(MMTV-PyVT)634Mul/J (PyVT) transgenic mouse. PQ1 was determined to have an IC50 of 6.5 µM in FMC2u cells, while inducing an upregulation in Cx43 expression. The effects of Cx43 modulation in FMC2u cell survival was determined through transfection experiments with Cx43 cDNA, which induced an elevated level of protein expression similar to that seen with PQ1 exposure, or siRNA to silence Cx43 protein expression. Overexpression or silencing of Cx43 led to a reduction or an increase in cell viability, respectively. The mitogen-activated protein kinase (MAPK) family has been implicated in the regulation of cell survival and cell death; therefore, the gap junctional intercellular communication (GJIC)-independent function of PQ1 and Cx43 in the Raf/Mitogen-activated protein kinase/ERK kinase/extracellular-signal-regulated kinase (Raf-MEK-ERK) cascade of cellular survival and p38 MAPK-dependent pathway of apoptosis were explored. PQ1 treatment activated p44/42 MAPK, while the overexpression of Cx43 resulted in a reduced expression. This suggests that PQ1 affects the Raf-MEK-ERK cascade independent of Cx43 upregulation. Both overexpression of Cx43 and PQ1 treatment stimulated an increase in the phosphorylated form of p38-MAPK, reduced levels of the anti-apoptotic protein Bcl-2, and increased the cleavage of pro-caspase-3. Silencing of Cx43 protein expression led to a reduction in the phosphorylation of p38-MAPK and an increase in Bcl-2 expression. The mechanism behind PQ1-induced cytotoxicity in FMC2u mammary carcinoma cells is thought to be attributed to the change in Cx43 expression. Furthermore, PQ1-induced apoptosis through the upregulation of Cx43 may depend on p38 MAPK, highlighting that the effect of PQ1 on gap junctions as well as cellular survival via a MAPK-dependent pathway.  相似文献   
74.
We examined the in vitro metabolism of (+)-terpinen-4-ol by human liver microsomes and recombinant enzymes. The biotransformation of (+)-terpinen-4-ol was investigated by gas chromatography-mass spectrometry (GC-MS). (+)-Terpinen-4-ol was found to be oxidized to (+)-(1R,2S,4S)-1,2-epoxy-p-menthan-4-ol, (+)-(1S,2R,4S)-1,2-epoxy-p-menthan-4-ol, and (4S)-p-menth-1-en-4,8-diol by human liver microsomal P450 enzymes. The identities of (+)-terpinen-4-ol metabolites were determined through the relative abundance of mass fragments and retention times on GC-MS. Of 11 recombinant human P450 enzymes tested, CYP1A2, CYP2A6, and CYP3A4 were found to catalyze the oxidation of (+)-terpinen-4-ol. Based on several lines of evidence, CYP2A6 and CYP3A4 were determined to be major enzymes involved in the oxidation of (+)-terpinen-4-ol by human liver microsomes. First, of the 11 recombinant human P450 enzymes tested, CYP1A2, CYP2A6 and CYP3A4 catalyzed oxidation of (+)-terpinen-4-ol. Second, oxidation of (+)-terpinen-4-ol was inhibited by (+)-menthofuran and ketoconazole, inhibitors known to be specific for these enzymes. Finally, there was a good correlation between CYP2A6 and CYP3A4 activities and (+)-terpinen-4-ol oxidation activities in the 10 human liver microsomes.  相似文献   
75.
Combination of the reactions by means of membrane separation techniques are of interest. The CO2 methanation was combined with NH3 decomposition by in situ H2 separation through a Pd membrane. The CO2 methanation reaction in the permeate side was found to significantly enhance the H2 removal rate of Pd membrane compared to the use of sweep gas. The reaction rate of CO2 methanation was not influenced by H2 supply through the Pd membrane in contrast to NH3 decomposition in the retentate side. However, the CH4 selectivity could be improved by using a membrane separation technique. This would be caused by the active dissociated H species which might immediately react with adsorbed CO species on the catalysts to CH4 before those CO species desorbed. From the reactor configuration tests, the countercurrent mode showed higher H2 removal rate in the combined reaction at 673 K compared to the cocurrent mode but the reaction rate in CO2 methanation should be improved to maximize the perfomance of membrane reactor.  相似文献   
76.
Novel organic solvent‐free bio‐based epoxy resin for coating was prepared from cashew nut shell liquid which is one of renewable resources. The epoxy coating was fabricated by the reaction between amine compounds and epoxy cardanol prepolymer (ECP). The drying, physical, and thermal properties of the epoxy were investigated and compared with those of the commercial cashew coating. The ECP was synthesized by thermal polymerization under the various conditions. Based on the FT‐IR analysis, hydroxyl and carbonyl groups were generated, and viscosity increased with increasing heating temperature and time. On the other hand, the NMR analysis showed decrease in the degree of unsaturation in the side group of cardanol. Based on these results, the polymerization of the ECP could be autoxidized in the unsaturated group in the side chains. The drying time until harden dry of the ECP coating took about 2.5 h at room temperature, which is faster than that of the commercial cashew coating. This is because that the curing of ECP coating was based on the prepolymer (i.e., high molecular weight) and crosslink reaction between epoxy and amine groups. The ECP coating was rubbery state due to the flexible side chains of cardanol. Furthermore, the ECP coating improved chemical stability compared with the commercial cashew. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 2468–2478, 2013  相似文献   
77.
生成对抗式网络(generative adversarial network, GAN)由负责学习数据分布的生成器和负责鉴别样本真伪的判别器构成,二者在相互对抗过程中互相学习逐渐变强。该网络模型使深度学习方法可以自动学习损失函数,减少了对专家知识的依赖,已经广泛应用于自然图像处理领域,对解决医学影像处理的相关瓶颈问题亦具有巨大应用前景。本文旨在找到生成对抗式网络与医学影像领域面临挑战的结合点,通过分析已有工作对未来研究方向进行展望,为该领域研究提供参考。1)阐述了生成对抗式网络的基本原理,从任务拆分、条件约束以及图像到图像的翻译等角度对其衍生模型进行分析回顾;2)对生成对抗式网络在医学影像领域中的数据增广、模态迁移、图像分割以及去噪等方面的应用进行回顾,分析各方法的优缺点与适用范围;3)对现有图像生成质量评估方法进行小结;4)总结生成对抗式网络在医学影像领域的研究进展,并结合该领域问题特性,指出现有理论应用存在的不足与改进方向。生成对抗式网络提出以来,理论不断完善,在医学影像的处理应用中也取得了长足发展,但仍然存在一些亟待解决的问题,包括3维数据合成、几何结构合理性保持、无标记和未配对...  相似文献   
78.
Zucker fatty diabetes mellitus (ZFDM) rats harboring the missense mutation (fa) in a leptin receptor gene have been recently established as a novel animal model of obesity and type 2 diabetes (T2D). Here, we explored changes in cardiovascular dynamics including blood pressure and heart rate (HR) associated with the progression of obesity and T2D, as well as pathological changes in adipose tissue and kidney. There was no significant difference in systolic blood pressure (SBP) in ZFDM-Leprfa/fa (Homo) compared with ZFDM-Leprfa/+ (Hetero) rats, while HR and plasma adrenaline in Homo were significantly lower than Hetero. The mRNA expression of monocyte chemotactic protein-1 in perirenal white adipose tissue (WAT) from Homo was significantly higher than Hetero. Interscapular brown adipose tissue (BAT) in Homo was degenerated and whitened. The plasma blood urea nitrogen in Homo was significantly higher than Hetero. In summary, we demonstrated for the first time that HR and plasma adrenaline concentration but not SBP in Homo decrease with obesity and T2D. In addition, inflammation occurs in WAT from Homo, while whitening occurs in BAT. Further, renal function is impaired in Homo. In the future, ZFDM rats will be useful for investigating metabolic changes associated with the progression of obesity and T2D.  相似文献   
79.
This paper describes the numerical method of a distributed parameter analysis code SPIRAL for the calculation of fluid flow and temperature in arbitrary channel geometries, discusses the numerical method in the modeling and solution of the problem, and presents some results, including comparison with experiments.

The derivation and solution of the finite element equations is discussed. In order to overcome difficulties arising from the geometry, the Galerkin finite element method using isoparametric elements was employed, and a procedure of finite element generation using curvilinear coordinate system was developed.

The SPIRAL code permits calculation of the fine structure of the multi-dimensional steady-state single-phase fluid flow and temperature fields in LMFBR fuel pin subassemblies in the presence of wire spacers. Calculated results are presented for crossflow velocity distributions and crossflow pressure drop characteristics in a tube bundle geometry with and without wire spacers, natural convection and heat transfer in horizontal annuli, flow in a wire-wrapped 7-pin bundle geometry and fully developed turbulent flow in a parallel 4-rod array contained in a rectangular duct.  相似文献   

80.
The basidiomycete Lentinus edodes (Le.) ras gene (or its cDNA clone) [Hori et al., Gene 105 (1991) 91-96] was utilized to identify and clone the corresponding gene (Cc.ras)-containing genomic fragment from the basidiomycete, Coprinus cinereus. Cc.ras encodes 215 amino acids (aa) interrupted by six small introns. The deduced Cc.RAS protein exhibits significant homology (84.7% identical) to the Le.RAS protein (217 aa) in size and aa sequence.  相似文献   
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