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71.
72.
In this study we tried to develop an analysis program that can simulate the collapsing process of timber-frame structures under dynamic loading by adopting the extended distinct element method (EDEM). Using the EDEM, it is possible to trace the movement of any parts that were separated from unity after the failure of connecting elements, a property that fits our purpose well. As a preliminary study, simple two-story frame structures were modeled and examined by our program. Each model is an assembly of frame members composed of the EDEM elements. The spring elements of the joints have less rigidity than those of the frame members. Several models were analyzed under dynamic loading. The models varied in the configuration of bracing shear walls. Experiments with a one-ninth model were carried out under similar conditions, and the results were compared with the results from numerical simulations. Simulated results showed various collapsing processes corresponding to the arrangement of the bracing shear wall, and the simulated aspects gave good agreement with the results of the experiments under similar conditions.Part of this paper was presented at the 50th Annual Meeting of the Japan Wood Research Society, Kyoto, April 2000 相似文献
73.
Intercalation of wood charcoal with sulfuric acid (H2SO4) was investigated. Carbonized sugi (Japanese cedar) samples were prepared by heating at various temperatures in the range
1700°–2700°C. Electrochemical oxidization was carried out in H2SO4 and the feasibility of intercalation was determined. In potentiometric analysis, plateaus appeared for samples carbonized
at temperatures above 2300°C. In their X-ray diffraction profiles, the peak at around 26° was shifted to a smaller angle of
about 22.4°. These results can be considered as signs of intercalation with acid molecules. Fourier transform infrared analysis
of charcoal heated at 2700°C, following washing with water and drying of the sample, showed a band at 1220 cm−1 that was assigned to a sulfonate group. This band was not observed for samples heated at 1900°C. These observations suggest
the occurrence of intercalation in the former charcoal, but not in the latter. It is concluded that wood charcoal can undergo
intercalation when it has ordered stacking of hexagonal carbon layers.
Part of this article was presented at the 55th, 56th, and 57th Annual Meetings of the Japan Wood Research Society, Akita,
Hiroshima, and Tsukuba, August 2006, August 2007, and March 2008, respectively, and at the International Conference on Carbon
“CARBON 2008,” Nagano, July 2008 相似文献
74.
Masamitsu Nakajima Yuzo Furuta Yutaka Ishimaru Makoto Ohkoshi 《Journal of Wood Science》2009,55(4):258-263
To clarify the effects of lignin on the fixation of bending deformation by cooling, cooling set for delignified woods with
various lignin residues were investigated to compare with mechanical and dynamic viscoelastic properties. Bending tests showed
that steep reductions occurred in the modulus of elasticity and modulus of rupture with delignification during the initial
stage of delignification. The dynamic viscoelastic measurements revealed that the peak temperature of tan δ due to micro-Brownian
motion of lignin was reduced with delignification, and the peak disappeared in the temperature range of 5°–100°C for the specimens
that had lost more than 21% of their weight. On the other hand, no clear change in residual set was found in the range of
0%–15% of weight loss in spite of a marked reduction in lignin content. Subsequently, set decreased steeply for the specimens
delignified beyond 15% of weight loss. It was suggested that cooling set is not determined solely by lignin content but is
influenced by changes in the quality of lignin due to delignification. Lignin quality affects the balance of the elastic potential
to recover from deformation and its viscosity, which is an indication of resistance against flow.
Part of this report was presented at the 57th Annual Meeting of the Japan Wood Research Society, Hiroshima, August 2007 相似文献
75.
Takafumi Nakagawa Masamitsu Ohta Takahiro Tsuchimoto Naohito Kawai 《Journal of Wood Science》2010,56(4):284-292
In this study, we developed a new analysis method that enables numerical simulations of the collapse process of real-size
wooden houses and evaluated the accuracy thereof by carrying out numerical simulations by shaking table tests. The distinct
element method was adopted as the basic theory of our numerical analysis. This research is the first approach in which the
extended distinct element method was used for Japanese timber post-and-beam construction. The size of the analysis model is
a 5.5 m × 5.5 m, two-story real-size wooden house. The three analytical models were developed in terms of the strength of
exterior mortar walls. The simulation results were compared with the shaking table test results. One of the collapsing processes
of the numerical simulation corresponds well to the experiment results. Assessment of the possibility of collapse for real-size
wooden houses was determined to be possible using our newly developed numerical analysis method. 相似文献
76.
Murakoshi F Xiao L Matsubara R Sato R Kato Y Sasaki T Fukuda Y Tada C Nakai Y 《Veterinary parasitology》2012,187(1-2):123-128
Cattle are major hosts of Cryptosporidium spp. Cryptosporidiosis in neonatal calves is associated with retarded growth, weight loss and calf mortality, and zoonotic infections in humans. In many areas, cow-calf glazing system is an important beef cattle rearing method with distinct advantages in terms of cost and the labor required. However, few epidemiologic studies of Cryptosporidium spp. have been conducted in this system, especially using molecular diagnostic tools. To understand the transmission of Cryptosporidium spp. in a grazing system, we followed cryptosporidiosis on a grazing farm in Osaki City, Miyagi Prefecture, in northwest Japan for one year. Fecal samples were collected from Japanese Black and Japanese Shorthorn cattle and examined by PCR-RFLP and sequence analyses. Of 113 fecal samples collected in October 2010, 23 (20%) were positive for Cryptosporidium, including 15 samples (13%) having C. bovis, 6 (5%) having C. ryanae, and 2 (2%) having mixed infections of both species. Additionally, C. bovis or C. ryanae was detected on all other sampling dates involving smaller numbers of animals. The infection rate of C. bovis was significantly different among age groups, and calve-to-calve infection might be the major route of cryptosporidiosis transmission in beef cattle. Interestingly, one animal had C. bovis infection or re-infection for one year. Our results suggest that C. bovis and C. ryanae are distributed in Japan, but might have low level of detection in grazing beef cattle. 相似文献
77.
Izumi Y Kamei E Miyamoto Y Ohtani K Masunaka A Fukumoto T Gomi K Tada Y Ichimura K Peever TL Akimitsu K 《Phytopathology》2012,102(8):741-748
78.
Uno K Katagiri H Yamada T Ishigaki Y Ogihara T Imai J Hasegawa Y Gao J Kaneko K Iwasaki H Ishihara H Sasano H Inukai K Mizuguchi H Asano T Shiota M Nakazato M Oka Y 《Science (New York, N.Y.)》2006,312(5780):1656-1659
Coordinated control of energy metabolism and glucose homeostasis requires communication between organs and tissues. We identified a neuronal pathway that participates in the cross talk between the liver and adipose tissue. By studying a mouse model, we showed that adenovirus-mediated expression of peroxisome proliferator-activated receptor (PPAR)-g2 in the liver induces acute hepatic steatosis while markedly decreasing peripheral adiposity. These changes were accompanied by increased energy expenditure and improved systemic insulin sensitivity. Hepatic vagotomy and selective afferent blockage of the hepatic vagus revealed that the effects on peripheral tissues involve the afferent vagal nerve. Furthermore, an antidiabetic thiazolidinedione, a PPARg agonist, enhanced this pathway. This neuronal pathway from the liver may function to protect against metabolic perturbation induced by excessive energy storage. 相似文献
79.
Nishikawa S Mizuno H Ohgami N Tada T Kumazawa Z Inagaki M Kashimura N 《Journal of agricultural and food chemistry》2000,48(11):5302-5306
Crystal structures of conformationally restricted (Z)- and (E)-6-styrylpurines with the beta-substituents involving hydrogen, chlorine, and bromine atoms as well as a methylthio group were studied as conformer models of N(6)-adenines in relation to active conformation of cytokinins. X-ray crystallographic analyses confirmed that all of the trans-isomers exist in an anti conformation, whereas the cis-isomers except the (E)-methylthio derivative adopt a syn conformation. The derivative with a bulky beta-substituent was found to be in an anti conformation in contrast to the other cis-isomers. The preferred anti conformation and potent cytokinin activity of the trans-isomers supports the anti-transoid form as the most plausible active conformation of N(6)-adenines. In addition, it is likely that the syn-cisoid form of N(6)-adenines is also involved in receptor binding, by considering both the preferred syn conformation of the cis-isomers and their moderate activity, although it does not play a major role compared to the anti-transoid form. 相似文献
80.
Tanaka J Nakanishi T Ogawa K Tsuruma K Shimazawa M Shimoda H Hara H 《Journal of agricultural and food chemistry》2011,59(2):528-536
This study evaluated the protective effects of purple rice ( Oryza sativa L.) bran extract (PRE) and its major anthocyanidins (cyanidin and peonidin) against light-induced retinal damage. In an in vitro experiment, cultured murine photoreceptor cells (661W) were damaged by a 24 h exposure to light. Viability of 661W after light treatment, assessed by the tetrazolium salt (WST-8) assay and Hoechst 33342 nuclear staining, was improved by the addition of PRE, cyanidin, and peonidin. Intracellular radical activation in 661W, evaluated using the reactive oxygen species (ROS) sensitive probe 5-(and 6)-chloromethyl-2,7-dichlorodihydrofluorescein diacetate acetyl ester (CM-H(2)DCFDA), was reduced by PRE and its anthocyanidins. Electron spin resonance (ESR) measurements showed that PRE, peonidin, and cyanidin all exhibited radical scavenging activities against 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical, superoxide anion radical ((?)O(2)(-)), and hydroxyl radical ((?)OH). In an in vivo mouse experiment, intravitreous injection of PRE significantly suppressed photoreceptor degeneration induced by exposure to light as revealed by histological analysis using hematoxylin-eosin staining. These findings suggest that PRE and its anthocyanidins possess protective effects with antioxidation mechanism in both in vitro and in vivo models of retinal diseases. 相似文献