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排序方式: 共有469条查询结果,搜索用时 31 毫秒
101.
Kazuhiro Yamamura Syuji Fujii Yoshinobu Nakamura Kazuko Fujiwara Shigeki Hikasa Yoshiaki Urahama 《应用聚合物科学杂志》2013,129(3):1008-1018
The influence of diblock copolymer addition on the tack properties of a polyacrylic triblock copolymer/tackifier system was investigated. For this purpose, poly(methyl methacrylate)‐block‐poly(n‐butyl acrylate)‐block‐poly(methyl methacrylate) triblock copolymer (MAM) and a 1/1 blend with a diblock copolymer consisting of the same components (MA) were used as base polymers, and a tackifier was added in amounts ranging from 10 to 30 wt %. The temperature dependence of tack was measured by a probe tack test. The tack of MAM/MA at room temperature was significantly higher than that of MAM, and the improvement of MAM/MA upon the addition of the tackifier was higher than that of MAM. The peeling process at the probe/adhesive interface during the probe tack test was observed using a high‐speed microscope. It was found that for MAM/MA, cavitation was caused in the entire adhesive layer, and peeling initiation was delayed by the absorption of strain energy due to deformation of the adhesive layer. In contrast, for MAM, peeling progressed linearly from the edge to the center of the probe. The greater flexibility of the soft block chain in the diblock copolymer resulted in improved interfacial adhesion. 1H pulse nuclear magnetic resonance analysis showed that the addition of the tackifier improved the cohesive strength of the adhesive. Adhesion strength is affected by two factors: the development of interfacial adhesion and cohesive strength. In the MAM/MA/tackifier system, the presence of MA and the tackifier improved the interfacial adhesion and cohesive strength, respectively. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013 相似文献
102.
Kiyotaka Yamamura Shigeru Tanaka 《International Journal of Circuit Theory and Applications》2001,29(4):403-411
In this letter, an effective technique is proposed for improving the computational efficiency of the contraction‐type LP test algorithm, which is an algorithm for finding all solutions of piecewise‐linear resistive circuits. Using the proposed technique, all solutions of a large‐scale problem, where the number of variables is 100 and the number of linear regions is 10100, could be found in less than 10 min using a 360 MHz computer. Copyright 2001 John Wiley & Sons, Ltd. 相似文献
103.
Akifumi Nagatomo Kiyofumi Ninomiya Shinsuke Marumoto Chie Sakai Shuta Watanabe Wakana Ishikawa Yoshiaki Manse Takashi Kikuchi Takeshi Yamada Reiko Tanaka Osamu Muraoka Toshio Morikawa 《International journal of molecular sciences》2022,23(21)
The seed oil of Carapa guianensis Aublet (Andiroba) has been used in folk medicine for its insect-repelling, anti-inflammatory, and anti-malarial activities. This study aimed to examine the triglyceride (TG) reducing effects of C. guianensis-derived limonoids or other commercially available limonoids in human hepatoblastoma HepG2 cells and evaluate the expression of lipid metabolism or autophagy-related proteins by treatment with 7-deacetoxy-7-oxogedunin (DAOG; 1), a principal limonoid of C. guianensis. The gedunin-type limonoids, such as DAOG (% of control at 20 μM: 70.9 ± 0.9%), gedunin (2, 74.0 ± 1.1%), epoxyazadiradione (4, 73.4 ± 2.0%), 17β-hydroxyazadiradione (5, 79.9 ± 0.6%), 7-deacetoxy-7α-hydroxygedunin (6, 61.0 ± 1.2%), andirolide H (7, 87.4 ± 2.2%), and 6α-hydroxygedunin (8, 84.5 ± 1.1%), were observed to reduce the TG content at lower concentrations than berberine chloride (BBR, a positive control, 84.1 ± 0.3% at 30 μM) in HepG2 cells pretreated with high glucose and oleic acid. Andirobin-, obacunol-, nimbin-, and salannin-type limonoids showed no effect on the intracellular TG content in HepG2 cells. The TG-reducing effect of DAOG was attenuated by the concomitant use of compound C (dorsomorphin), an AMPK inhibitor. Further investigation on the detailed mechanism of action of DAOG at non-cytotoxic concentrations revealed that the expressions of autophagy-related proteins, LC3 and p62, were upregulated by treatment with DAOG. These findings suggested that gedunin-type limonoids from Andiroba could ameliorate fatty liver, and that the action of DAOG in particular is mediated by autophagy. 相似文献
104.
Kae Tomotsune Fernanda Raya Tonetti Hiroya Mizuno Mariano Elean Kohtaro Fukuyama Binghui Zhou Wakako Ikeda-Ohtsubo Keita Nishiyama Akihiro Yamamura Hideaki Karasawa Shinobu Ohnuma Akira Horii Tadao Saito Haruki Kitazawa Julio Villena 《International journal of molecular sciences》2022,23(22)
Both viable and non-viable orally administered Lacticaseibacillus rhamnosus CRL1505 modulate immunity in local (intestine) and distal (respiratory) mucosal sites. So, intestinal adhesion and colonization are not necessary for this probiotic strain to exert its immunomodulatory effects. In this work, a mucus-binding factor knockout CRL1505 strain (ΔmbfCRL1505) was obtained and the lack of binding ability to both intestinal epithelial cells and mucin was demonstrated in vitro. In addition, two sets of in vivo experiments in 6-week-old Balb/c mice were performed to evaluate ΔmbfCRL1505 immunomodulatory activities. (A) Orally administered ΔmbfCRL1505 prior to intraperitoneal injection of the Toll-like receptor 3 (TLR3) agonist poly(I:C) significantly reduced intraepithelial lymphocytes (CD3+NK1.1+CD8αα+) and pro-inflammatory mediators (TNF-α, IL-6 and IL-15) in the intestinal mucosa. (B) Orally administered ΔmbfCRL1505 prior to nasal stimulation with poly(I:C) significantly decreased the levels of the biochemical markers of lung tissue damage. In addition, reduced recruitment of neutrophils and levels of pro-inflammatory mediators (TNF-α, IL-6 and IL-8) as well as increased IFN-β and IFN-γ in the respiratory mucosa were observed in ΔmbfCRL1505-treated mice when compared to untreated control mice. The immunological changes induced by the ΔmbfCRL1505 strain were not different from those observed for the wild-type CRL1505 strain. Although it is generally accepted that the expression of adhesion factors is necessary for immunobiotics to induce their beneficial effects, it was demonstrated here that the mbf protein is not required for L. rhamnosus CRL1505 to exert its immunomodulatory activities in local and distal mucosal sites. These results are a step forward towards understanding the mechanisms involved in the immunomodulatory capabilities of L. rhamnosus CRL1505. 相似文献
105.
106.
N Tanahashi K Yokota JY Ahn CH Chung T Fujiwara E Takahashi GN DeMartino CA Slaughter T Toyonaga K Yamamura N Shimbara K Tanaka 《Canadian Metallurgical Quarterly》1997,2(3):195-211
The information processing capabilities of biomolecular excitable media based on nonlinear dynamic mechanisms are discussed. Given even the simplest medium geometry, dynamics and information processing features inherent in biomolecular excitable media proves to be diverse and sophisticated. For the case of pseudo two-dimensional versions these media can be described in terms of neural networks having lateral connections. The main responses of shunting on-center off-surround feedback neural networks and pseudo two-dimensional excitable systems to the external excitations are surprisingly similar. The excitable media are capable of short-time memory, of contour enhancement and quenching or amplifying small features depending on medium state. The analogies discussed reaffirm specific neural net characteristics of excitable media and give the opportunity to estimate more accurate excitable medium characteristics. 相似文献
107.
108.
Self-diffusion coefficients of oxygen ion in polycrystalline and single-crystal magnesioferrites have been measured by a gas-solid isotopic exchange technique using18O as a tracer at temperature in the range 975 to 1465° C. A new method was considered for the oxygen volume diffusion in polycrystalline magnesio-ferrite, and its reliability is discussed. The volume diffusion coefficients of polycrystalline magnesio-ferrite (MgO/Fe2O3=0.95 in mole ratio) can be expressed asD=1.51×10–1exp (–78 600/RT) cm2 sec–1 (1135 to 1465° C) andD=1.2×10–7exp (–38 000/RT) cm2sec–1 (975 to 1135° C). The volume diffusion coefficients of the polycrystal in the high temperature range were very close to those of single crystal ferrite of the same composition as the polycrystal. The activation energy of grain-boundary diffusion in this polycrystal was expected to be greater than that of the volume diffusion. A possible interpretation of this unusual behaviour is given in terms of an increased enrichment of Fe2+ ion along the grain boundary with temperature elevation, by which oxygen vacancies increase. 相似文献
109.
Ceria–samaria (CeO2–Sm2O3) is one of the most interesting fluorite oxides since its ionic conductivity is higher than that of yttria-stabilized zirconia in air. However, these CeO2 -based oxides are partially reduced and develop electronic conductivity under fuel cell operating conditions. In their application to the SOFC system, their current densities and power densities are not at a satisfactory level. For the development of high-performance CeO2 electrolytes, it is important that the fluorite lattice of CeO2-based oxide be improved from the viewpoint of crystallography. In this study, it is assumed that the reduction of Ce4+ in the fluorite lattice was inhibited by expansion of the CeO2 lattice. In order to investigate the contribution of the expanded CeO2 lattice to reduction resistance, CeO2–Sm2O3 solid solution, calcia-doped CeO2–Sm2O3 solid solution, and a small amount of alkali element-doped CeO2–Sm2O3 -based oxide were prepared for comparison. It was found that the calcia or a small amount of alkali element-doped CeO2 solid solution enhanced the oxide ionic conductivity. The power density of the latter showed a high value at 800°C. It is concluded that the improved fuel cell performance can be attributed to the good reduction resistance in the fuel cell atmosphere. 相似文献
110.
M Yang K Yamamura Y Yan Y Fukamachi T Hirano T Kawamoto K Higashi 《Canadian Metallurgical Quarterly》1997,19(4):277-286
The fluorescent indicator Fura-2 was used to characterize the store-operated Ca2+ entry in insulin-releasing pancreatic beta-cells. To avoid interference with voltage-dependent Ca2+ entry, the cells were hyperpolarized with 400 microM diazoxide and the channel blocker methoxyverapamil was also present in some experiments. The cytoplasmic Ca2+ concentration ([Ca2+]j) of hyperpolarized mouse beta-cells was strikingly resistant to changes in external Ca2+. In cells exposed to 20 mM glucose, stimulation with 100 microM carbachol induced an initial [Ca2+]j peak followed by a sustained increase due to store-operated influx of the cation. Store-operated influx was also induced by the intracellular Ca(2+)-ATPase inhibitor thapsigargin. In the presence of store-operated influx, [Ca2+]j became markedly sensitive to variations in external Ca2+, but this sensitivity was blocked by La3+. In beta-cells exposed to both Ca2+ and Mn2+ there was slow Mn2+ quenching of the Fura-2 fluorescence, which was accelerated upon stimulation of store-operated influx. This acceleration was reversed by glucose-stimulated filling of the internal Ca2+ stores. The store-operated Ca2+ entry increased markedly during culture of the beta-cells. Activation of protein kinase C by the phorbol ester 12-O-tetradecanoylphorbol-13 acetate, inhibition of serine/threonine phosphatase by okadaic acid and inhibition of tyrosine kinase by genistein had little effect on the store-operated influx of Ca2+. In beta-cells equilibrated in 5 mM Sr2+, carbachol exposure resulted in a pronounced cytoplasmic Sr2+ ([Sr2+]j) peak due to intracellular mobilization, but little or no sustained elevation. Moreover, after activating the store-operated pathway by exposure to thapsigargin, variations in extracellular Sr2+ between 0-2 mM had only marginal effects on [Sr2+]j. Although the store-operated influx apparently accounts for a minor fraction of the Ca2+ entry, its depolarizing influence may under certain conditions be up-regulated with resulting distortion of the beta-cell function. 相似文献