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Joo-Young Lee Yota Yamamoto Riichi Oe Su-Young Son Hitoshi Wakabayashi Yutaka Tochihara 《Ergonomics》2014,57(8):1213-1221
The purpose of this study was to investigate the physiological and subjective responses of the European, Japanese (JPN) and US firefighters' helmet, gloves and boots for international standardisation. Three experimental conditions were evaluated (clothing mass: 9.4, 8.2 and 10.1 kg for the three conditions, respectively) at the air temperature of 32°C and 60% relative humidity. The results showed that there was no significant difference among the three conditions in oxygen consumption, heart rate, total sweat rate, rectal temperature and mean skin temperature, whereas peripheral temperatures and subjective perceptions were lower in the JPN condition than in the other conditions (P < 0.05). These results indicate that a 0.5-kg reduction in helmet mass and a 1.1-kg reduction in boot mass during exercise resulted in a significant decrease in head and leg temperatures and subjective perceptions, while a 1.9-kg reduction in total clothing mass had insignificant influences on the metabolic burden and overall body temperature. 相似文献
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Hiromasa Iwai Yota Konishi Kazuki Saimyou Sayuri Kimoto Fusao Oka 《Soils and Foundations》2018,58(5):1113-1132
Methane hydrates (MHs) have been recognized as an important material for use as a new energy resource. Recently, not only MHs, but also carbon dioxide hydrates (CO2-hydrates), have been attracting attention from the viewpoint of CO2 storage in the form of CO2-hydrates. It is essential, therefore, to investigate the mechanical behaviour of gas hydrate-bearing sediments in order to achieve safe MH extraction and to ensure the long-term stability of CO2-hydrate-storaged submarine sediments. In order to gain further knowledge of CO2-hydrate-bearing sediments, we carried out three kinds of laboratory experiments on synthetic CO2-hydrate-bearing sand specimens: (1) undrained triaxial compression tests with a constant strain rate, (2) undrained triaxial compression tests with a step-changed strain rate, and (3) dissociation tests on CO2-hydrate-bearing sand specimens using the thermal stimulation method.The main findings obtained from these three experiments are as follows: First, it was found that CO2-hydrate-bearing sand shows larger strength and larger positive dilatancy than water-saturated sand without CO2-hydrates under undrained conditions. Second, CO2-hydrate-bearing sand clearly exhibits strain rate dependency with an increase in hydrate saturation. It is interesting to note that hydrate saturation’s dependency on strength does not appear in cases where the strain rate is quite slow. Third, a drastic increase in pore pressure and extensive tensile strain are observed simultaneously during the dissociation of CO2-hydrates. The pore gas pressure of CO2, produced by the hydrate dissociation, can exceed the liquefied boundary of CO2-gas, and the increase in pore gas pressure can be limited by the liquefaction of CO2-gas. 相似文献
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Chemistry,Properties, and in Vitro and in Vivo Applications of 2′‐O‐Methoxyethyl‐4′‐thioRNA,a Novel Hybrid Type of Chemically Modified RNA
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Yota Saito Yosuke Hashimoto Mai Arai Noriko Tarashima Tadashi Miyazawa Kazuya Miki Dr. Mayumi Takahashi Prof. Dr. Kazuhiro Furukawa Prof. Dr. Naoshi Yamazaki Prof. Dr. Akira Matsuda Prof. Dr. Tatsuhiro Ishida Prof. Dr. Noriaki Minakawa 《Chembiochem : a European journal of chemical biology》2014,15(17):2535-2540
We report the synthesis, properties, and in vitro and in vivo applications of 2′‐O‐methoxyethyl‐4′‐thioRNA (MOE‐SRNA), a novel type of hybrid chemically modified RNA. In its hybridization with complementary RNA, MOE‐SRNA showed a moderate improvement of Tm value (+3.4 °C relative to an RNA:RNA duplex). However, the results of a comprehensive comparison of the nuclease stability of MOE‐SRNA relative to 2′‐O‐methoxyethylRNA (MOERNA), 2′‐O‐methyl‐4′‐thioRNA (Me‐SRNA), 2′‐O‐methylRNA (MeRNA), 4′‐thioRNA (SRNA), and natural RNA revealed that MOE‐SRNA had the highest stability (t1/2>48 h in human plasma). Because of the favorable properties of MOE‐SRNA, we evaluated its in vitro and in vivo potencies as an anti‐microRNA oligonucleotide against miR‐21. Although the in vitro potency of MOE‐SRNA was moderate, its in vivo potency was significant for the suppression of tumor growth (similar to that of MOERNA). 相似文献
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Yota J. Ly H. Ramanathan R. Hsiang-Chih Sun Barone D. Nguyen T. Katoh K. Ohe M. Hubbard R.L. Hicks K. 《Semiconductor Manufacturing, IEEE Transactions on》2007,20(3):323-332
Photosensitive polybenzoxazole (PBO) film has been used in GaAs heterojunction bipolar transistor (HBT) technology for stress buffer and mechanical protection layer applications. However, this film needs to be cured at high temperatures for a long period of time in order to obtain its desired excellent material characteristics. High-temperature curing can result in degradation to the electrical characteristics and performance of the underlying GaAs devices due to limited thermal budget. In this paper, we have characterized the effects of curing the PBO film on GaAs HBT wafers using a conventional convection furnace and using a variable frequency microwave (VFM) furnace. The results show that a VFM cure can achieve similar excellent physical, mechanical, thermal, and chemical material characteristics at a lower curing temperature and in a much shorter time, as compared to convection furnace curing, therefore resulting in minimal GaAs device degradation. Based on these results, an optimum curing condition using the VFM method can be obtained that satisfies both stress buffer layer material and device requirements for GaAs HBT technology. 相似文献
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Tatsuya Sakamoto Tsutomu Iida Yota Ohno Masashi Ishikawa Yasuo Kogo Naomi Hirayama Koya Arai Takashi Nakamura Keishi Nishio Yoshifumi Takanashi 《Journal of Electronic Materials》2014,43(6):1620-1629
We examine the mechanical stability of an unconventional Mg2Si thermoelectric generator (TEG) structure. In this structure, the angle θ between the thermoelectric (TE) chips and the heat sink is less than 90°. We examined the tolerance to an external force of various Mg2Si TEG structures using a finite-element method (FEM) with the ANSYS code. The output power of the TEGs was also measured. First, for the FEM analysis, the mechanical properties of sintered Mg2Si TE chips, such as the bending strength and Young’s modulus, were measured. Then, two-dimensional (2D) TEG models with various values of θ (90°, 75°, 60°, 45°, 30°, 15°, and 0°) were constructed in ANSYS. The x and y axes were defined as being in the horizontal and vertical directions of the substrate, respectively. In the analysis, the maximum tensile stress in the chip when a constant load was applied to the TEG model in the x direction was determined. Based on the analytical results, an appropriate structure was selected and a module fabricated. For the TEG fabrication, eight TE chips, each with dimensions of 3 mm × 3 mm × 10 mm and consisting of Sb-doped n-Mg2Si prepared by a plasma-activated sintering process, were assembled such that two chips were connected in parallel, and four pairs of these were connected in series on a footprint of 46 mm × 12 mm. The measured power generation characteristics and temperature distribution with temperature differences between 873 K and 373 K are discussed. 相似文献
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Low-k dielectric carbon-doped silicon dioxide films created by Plasma Enhanced Chemical Vapor Deposition (PECVD) using a six-station sequential deposition system exhibit different glass transition behavior from films created by PECVD in a single deposition station. The enhanced glass transition temperature (Tg) for the PECVD thin films of a layer consisting of six sub-layer deposited in a six-station sequential deposition system to the Tg for films of a single layer deposited in a single deposition system is traced back to the introduced film interface effect inherent to the different deposition methods. Both types of PECVD thin films range in thickness from 50 to 1255 nm and show an increasing Tg with decreasing film thickness. The observed glass transition behavior for films with six sub-layers can be well explained by a theoretical model of thickness dependent Tg for multiple sub-layers obtained by modifying the currently existing theoretical model for the single layer thickness dependent Tg behavior, which explains the observed thickness dependent Tg for single layer PECVD thin films. 相似文献
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Hans L. Bodlaender Fedor V. Fomin Petr A. Golovach Yota Otachi Erik Jan van Leeuwen 《Algorithmica》2012,64(1):85-111
We study the problem of determining the spanning tree congestion of a?graph. We present some sharp contrasts in the parameterized complexity of this problem. First, we show that on apex-minor-free graphs, a general class of graphs containing planar graphs, graphs of bounded treewidth, and graphs of bounded genus, the problem to determine whether a given graph has spanning tree congestion at most k can be solved in linear time for every fixed k. We also show that for every fixed k and d the problem is solvable in linear time for graphs of degree at most d. In contrast, if we allow only one vertex of unbounded degree, the problem immediately becomes NP-complete for any fixed k??8. Moreover, the hardness result holds for graphs excluding the complete graph on 6 vertices as a minor. We also observe that for k??3 the problem becomes polynomially time solvable. 相似文献
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Keisuke Shigeta Kazuhiro Matsumoto Nobuyuki Tanaka Shuji Mikami Takeo Kosaka Yota Yasumizu Toshikazu Takeda Ryuichi Mizuno Eiji Kikuchi Mototsugu Oya 《International journal of molecular sciences》2022,23(9)
To evaluate biological characteristics and transitions of upper tract urothelial carcinoma (UTUC) through metachronous bladder tumors after radical nephroureterectomy (RNU), we conducted immunohistochemical (IHC) staining of tumor specimens of UTUC tumor origin, non-muscle-invasive bladder cancer (NMIBC) and MIBC progressed after intravesical recurrence (IVR), and bladder primary MIBC. Fibroblast growth factor receptor 3 (FGFR3), p53, cytokeratin 5/6 (CK5/6), and CK20 were stained to examine expression rates. After expression assessment with heatmap clustering, the overexpression of four biomarkers from UTUC origin to metachronous MIBC progression was analyzed with clinicopathological variables. We found that high CK20 and low CK5/6 expression were both observed in UTUC tumor origin and subsequent NMIBC after RNU. By investigating molecular expression in the IVR specimen, we observed that low pT stage bladder recurrence occupied the majority of CK20 high CK5/6 low expression, but would change to CK20 low CK5/6 high expression as it progressed to MIBC. UTUC metachronous MIBC has different characteristics compared with bladder primary MIBC, which comprises favorable biological features such as high FGFR3 expression, and follows favorable prognosis compared to those without FGFR3 expression. The present study demonstrated that the biological characteristics of UTUC tumor origin shifts from luminal to basal-like features with progression to MIBC, but FGFR3 expression taken over from UTUC origin may comprise a favorable entity compared to primary MIBC. 相似文献