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排序方式: 共有1620条查询结果,搜索用时 361 毫秒
991.
Yoshiyuki Kaji Wenwei Gu Masahiro Ishihara Taketoshi Arai Hitoshi Nakamura 《Nuclear Engineering and Design》2001,206(1)
The brittle damage constitutive equation developed by Chow and Yang is used to simulate the non-linear elastic deformation behavior of graphite using finite element method (FEM). This model is achieved by introducing a damage surface that is similar to the yield function in the conventional theory of plasticity. A special form of damage surfaces is constructed to illustrate the application of the model. For verifying the FEM program including the Chow and Yang model, the predicted deformations by this model are compared with both the experimental ones in the graphite structural model and the calculated ones without the continuum damage mechanics. 相似文献
992.
We have challenged to reduce an accelerator beam power for an accelerator-based BNCT facility. The required neutron source strength at the target has been estimated so as to make the epithermal neutron flux in the patient irradiation field exceed 1.7 × 109 n/cm2s. The energy of the incident proton and the arrangement of the moderator assemblies are optimized. The beam current and the accelerating voltage are determined so that the accelerator power becomes minimum. The beam power required for the treatment in one hour is 62.5 kW. The proposed facility is equipped with a 2.5 MeV proton accelerator of 25 mA. a lithium target, and a heavy water moderator contained in an aluminum tank. 相似文献
993.
Yoshihiko Tokuji Kyoko Akiyama Keita Yunoki Mikio Kinoshita Keiko Sasaki Hitoshi Kobayashi Masahiro Wada Masao Ohnishi 《Journal of food science》2009,74(7):H197-H203
ABSTRACT: To identify novel functions of the oral intake of sweet corn, we performed DNA microarray analysis of the livers of sweet corn‐fed mice. Functional annotation clustering 1600 genes with expression levels that were affected (more than 1.5‐fold change) by dietary sweet corn indicated that both cell proliferation and programmed cell death were modulated by sweet corn intake. In the Wnt signaling pathway, which is involved in cell proliferation, the levels of Jun and β‐catenin expression were downregulated by dietary sweet corn. The mRNA levels of Rb and p53, negative regulators of the cell cycle, were increased in mice fed with sweet corn. Dietary corn upregulated expression levels of genes that regulate apoptosis positively (for example, BOK, BID, CASP4). These results suggested that sweet corn is a valuable food for suppressing cancer. Oral administration of sweet corn inhibited tumor growth (36.6% reduce in tumor weight, P < 0.05) in mice inoculated with Ehrlich tumor cells. 相似文献
994.
Huiming Ning Yuan Li Yanping Cao Cheng Yan Takesi Azuma 《Science and Technology of Advanced Materials》2014,15(3)
The effects of acid treatment, vapor grown carbon fiber (VGCF) interlayer and the angle, i.e., 0° and 90°, between the rolling stripes of an aluminum (Al) plate and the fiber direction of glass fiber reinforced plastics (GFRP) on the mode II interlaminar mechanical properties of GFRP/Al laminates were investigated. The experimental results of an end notched flexure test demonstrate that the acid treatment and the proper addition of VGCF can effectively improve the critical load and mode II fracture toughness of GFRP/Al laminates. The specimens with acid treatment and 10 g m−2 VGCF addition possess the highest mode II fracture toughness, i.e., 269% and 385% increases in the 0° and 90° specimens, respectively compared to those corresponding pristine ones. Due to the induced anisotropy by the rolling stripes on the aluminum plate, the 90° specimens possess 15.3%–73.6% higher mode II fracture toughness compared to the 0° specimens. The improvement mechanisms were explored by the observation of crack propagation path and fracture surface with optical, laser scanning and scanning electron microscopies. Moreover, finite element analyses were carried out based on the cohesive zone model to verify the experimental fracture toughness and to predict the interface shear strength between the aluminum plates and GFRP laminates. 相似文献
995.
Fumisato Maesaka Masaomi Kuwada Shohei Horii Shingo Kishi Rina Fujiwara-Tani Shiori Mori Kiyomu Fujii Takuya Mori Hitoshi Ohmori Takuya Owari Makito Miyake Yasushi Nakai Nobumichi Tanaka Ujjal Kumar Bhawal Yi Luo Masuo Kondoh Kiyohide Fujimoto Hiroki Kuniyasu 《International journal of molecular sciences》2022,23(12)
The tight junction (TJ) protein claudin-4 (CLDN4) is overexpressed in bladder urothelial carcinoma (BUC) and correlates with cancer progression. However, the mechanism of CLDN4 upregulation and promotion of malignant phenotype is not clear. Here, we analyzed 157 cases of BUC and investigated the hypomethylation of CpG island in the CLDN4 promoter DNA and its correlation with cancer progression. In hypomethylated cases, CLDN4 expression, cell proliferation, stemness, and epithelial-mesenchymal transition were increased. Treatment of three human BUC cell lines with the demethylating agent aza-2′-deoxycytidine (AZA) led to excessive CLDN4 expression, and, specifically, to an increase in CLDN4 monomer that is not integrated into the TJ. The TJ-unintegrated CLDN4 was found to bind integrin β1 and increase stemness, drug resistance, and metastatic ability of the cells as well as show an anti-apoptosis effect likely via FAK phosphorylation, which reduces upon knockdown of CLDN4. Thus, CLDN4 is overexpressed in BUC by an epigenetic mechanism and the high expression enhances the malignant phenotype of BUC via increased levels of TJ-unintegrated CLDN4. CLDN4 promoter DNA methylation is expected to be a novel indicator of BUC malignant phenotype and a new therapeutic target. 相似文献
996.
997.
Katsuhiro Tokutake Masaru Takeuchi Shigeru Kurimoto Sota Saeki Yuta Asami Keiko Onaka Masaomi Saeki Tadayoshi Aoyama Yasuhisa Hasegawa Hitoshi Hirata 《International journal of molecular sciences》2022,23(15)
Promising treatments for upper motor neuron disease are emerging in which motor function is restored by brain–computer interfaces and functional electrical stimulation. At present, such technologies and procedures are not applicable to lower motor neuron disease. We propose a novel therapeutic strategy for lower motor neuron disease and injury integrating neural stem cell transplantation with our new functional electrical stimulation control system. In a rat sciatic nerve transection model, we transplanted embryonic spinal neural stem cells into the distal stump of the peripheral nerve to reinnervate denervated muscle, and subsequently demonstrated that highly responsive limb movement similar to that of a healthy limb could be attained with a wirelessly powered two-channel neurostimulator that we developed. This unique technology, which can reinnervate and precisely move previously denervated muscles that were unresponsive to electrical stimulation, contributes to improving the condition of patients suffering from intractable diseases of paralysis and traumatic injury. 相似文献
998.
Sota Saeki Katsuhiro Tokutake Masaki Takasu Shigeru Kurimoto Yuta Asami Keiko Onaka Masaomi Saeki Hitoshi Hirata 《International journal of molecular sciences》2022,23(15)
Neural cell transplantation targeting peripheral nerves is a potential treatment regime for denervated muscle atrophy. This study aimed to develop a new therapeutic technique for intractable muscle atrophy by the xenotransplantation of neural stem cells derived from pig fetuses into peripheral nerves. In this study, we created a denervation model using neurotomy in nude rats and transplanted pig-fetus-derived neural stem cells into the cut nerve stump. Three months after transplantation, the survival of neural cells, the number and area of regenerated axons, and the degree of functional recovery by electrical stimulation of peripheral nerves were compared among the gestational ages (E 22, E 27, E 45) of the pigs. Transplanted neural cells were engrafted at all ages. Functional recovery by electric stimulation was observed at age E 22 and E 27. This study shows that the xenotransplantation of fetal porcine neural stem cells can restore denervated muscle function. When combined with medical engineering, this technology can help in developing a new therapy for paralysis. 相似文献
999.
1000.
Siddabasave Gowda B. Gowda Hirotoshi Fuda Yusuke Yamamoto Hitoshi Chiba Shu-Ping Hui 《Lipids》2020,55(4):395-401
An efficient three-step strategy for the convenient synthesis of Sn-glycero-3-phosphoethanolamine (GroPEtn) from a commercially available 1,2-dipalmitoyl-sn-glycero-3-phosphoethanolamine (DPPE) is reported. Direct hydrolysis of DPPE produces a complex inseparable mixture, hence a protection and deprotection strategy is employed to prepare GroPEtn. The primary amine of DPPE is protected with a highly stable acid-labile trityl group, followed by strong base hydrolysis of N-trityl-DPPE gives N-trityl-GroPEtn. Further a mild, rapid, and efficient deprotection method is established using trifluoroacetic acid to remove N-trityl moiety, affords GroPEtn as a single product. This is the first semisynthetic approach and efficient method to produce GroPEtn with a total yield of 66% in three steps. GroPEtn did not show any cytotoxicity against human kidney (HK-2) cells and reporter gene assay for activation of Keap1-Nrf2-mediated antioxidant defense mechanism showed no significant effects. 相似文献