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61.
Biaxial tension-tension creep experiments were performed to study the effect of gas diffusion on creep behavior of polycarbonate. Experiments were conducted on a thin-walled tubular specimen by applying both gas pressure and axial tension at room temperature, and measuring axial strain and gas absorption. Experiments were performed with helium, nitrogen, air, carbon dioxide and Freon-22 1 Registered trademark, E. I. duPont de Nemours Co., Inc. . It was found that the creep deformation was highly affected by the solubility controlled gases, carbon dioxide and Freon. The absorption measurements showed that the gas absorption behavior was clearly affected by the creep deformation of the material. Also an anomalous diffusion-type behavior appeared even in permanent gas-polymer systems under creep conditions. The modified superposition principle satisfactorily predicted the recovery following creep. The axial creep for the biaxial tension-tension experiments was also computed from data previously reported for creep under combined tension and torsion of a different sample of polycarbonate. 相似文献
62.
Masahiko Satoh Tamie Suzuki Tetsuhito Sakurai Sumika Toyama Yayoi Kamata Shinya Kondo Yasushi Suga Mitsutoshi Tominaga Kenji Takamori 《International journal of molecular sciences》2021,22(19)
Neuronal morphological changes in the epidermis are considered to be one of causes of abnormal skin sensations in dry skin-based skin diseases. The present study aimed to develop an in vitro model optimised for human skin to test the external factors that lead to its exacerbation. Human-induced pluripotent stem cell-derived sensory neurons (hiPSC-SNs) were used as a model of human sensory neurons. The effects of chemical substances on these neurons were evaluated by observing the elongation of nerve fibers, incidence of blebs (bead-like swellings), and the expression of nicotinamide mononucleotide adenylyl transferase 2 (NMNAT2). The nerve fiber length increased upon exposure to two common cosmetic preservatives—methylparaben and phenoxyethanol—but not to benzo[a]pyrene, an air pollutant at the estimated concentrations in the epidermis. Furthermore, the incidence of blebs increased upon exposure to benzo[a]pyrene. However, there was a decrease in the expression of NMNAT2 in nerve fibers, suggesting degenerative changes. No such degeneration was found after methylparaben or phenoxyethanol at the estimated concentrations in the epidermis. These findings suggest that methylparaben and phenoxyethanol promote nerve elongation in hiPSC-SNs, whereas benzo[a]pyrene induces nerve degeneration. Such alterations may be at least partly involved in the onset and progression of sensitive skin. 相似文献
63.
Sumika Toyama Mitsutoshi Tominaga Kenji Takamori 《International journal of molecular sciences》2021,22(22)
Although histamine is a well-known itch mediator, histamine H1-receptor blockers often lack efficacy in chronic itch. Recent molecular and cellular based studies have shown that non-histaminergic mediators, such as proteases, neuropeptides and cytokines, along with their cognate receptors, are involved in evocation and modulation of itch sensation. Many of these molecules are produced and secreted by immune cells, which act on sensory nerve fibers distributed in the skin to cause itching and sensitization. This understanding of the connections between immune cell-derived mediators and sensory nerve fibers has led to the development of new treatments for itch. This review summarizes current knowledge of immune cell-derived itch mediators and neuronal response mechanisms, and discusses therapeutic agents that target these systems. 相似文献
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Effects of 5-fluorouracil (5-FU) and UFT on an experimental liver metastasis model were compared at equi-effective dosage levels against subcutaneous tumor of mouse colon 26. 5-FU at the dosage level of 40 mg/kg suppressed the subcutaneous tumor growth by 70.0% and 45.0% on day 13 and day 18, respectively, and UFT at 20 mg/kg provided almost equal suppression (63.0% and 48.0%). In the liver metastasis model, 5-FU at 40 mg/kg showed more potent prevention of the formation of metastatic foci (94.9%) than did UFT (60.4%) at 20 mg/kg. 5-FU at 40 mg/kg produced a much higher peak serum level of 5-FU than did UFT at 20 mg/kg and also showed a much higher AUC (area under the curve) level in the portal blood. These results suggest that oral administration of 5-FU might be useful in prevention of liver metastasis of colorectal cancer. 相似文献
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Lead supported on active carbon showed a catalytic activity for the vapor phase carbonylation of methanol under pressurized conditions in the presence of methyl iodide promoter. 相似文献
69.
Takashi Tatsumi Shigeki Kunitomi Jun Yoshiwara Atsushi Muramatsu Hiro-o Tominaga 《Catalysis Letters》1989,3(3):223-226
In the reaction of CO-H2-NH3 on Mo/SiO2 catalysts, HCN is formed and is considered to be the principal intermediate for the formation of CH3CN. At low temperature methylamine is also formed. 相似文献
70.
Influence of the methyl group on the dielectric constant of boron carbon nitride films containing it
Hidemitsu Aoki Takuro Masuzumi Makoto Hara Zhiming Lu Daisuke Watanebe Chiharu Kimura Takashi Sugino 《Diamond and Related Materials》2010,19(12):1437-1440
LSI interconnect insulators made using low dielectric constant (low-k) materials are required for high performance devices with a small RC delay. We investigated a boron carbon nitride film containing the methyl group (Me–BCN) using tris-di-methyl-amino-boron (TMAB: B[N(CH3)2]3) gas as a low-k material. In addition, we studied the influence of the methyl group on the dielectric constant (k-value) and the properties of the Me–BCN films. It was found that the k-value of the Me–BCN films decreases with increasing number of C–H bonds due to the methyl group (CH3). The number of O–H bonds due to water incorporation is suppressed by increasing the number of C–H bonds. Consequently, we suggested that a lower k-value can be realized by the suppression of water invasion by a hydrophobic surface due to methyl bonds. Thus, the control of the methyl group is important to achieve a low-k material using Me–BCN films. 相似文献