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21.
Makoto Kiguchi Yutaka Kataoka Hiroshi Matsunaga Koichi Yamamoto Philip D. Evans 《Journal of Wood Science》2007,53(3):234-238
The market for wood-fiber plastic composites (WPCs) is expanding rapidly in many countries including Japan, where WPCs are
mainly used for exterior products. In such applications, WPCs undergo undesirable color change, chalking, and shrinkage and
swelling, and accordingly there is a need to better understand the mechanisms responsible for the weathering of WPC and develop
methods of improving their weathering resistance. In this study, weatherability of WPC was assessed by natural and accelerated
weathering trials. Discoloration (whitening) of WPC during exposure was caused by degradation of both wood and plastic. Darker
color pigments as additives improved the color stability of WPC; however, chalking on the surfaces still occurred. The color
stability of WPC was improved by application of exterior coatings. Preweathering of WPC (before coatings were applied) increased
the absorption of coatings by the WPC and had a positive effect on the color stability and prevented chalking of the composites.
Parts of this study were presented at the IUFRO XXII World Congress Meeting, Brisbane, August 2005 and the IAWPS 2005, Yokohama,
November 2005 相似文献
22.
Transverse swelling and its anisotropy in hinoki (Chamaecyparis obtusa) in several kinds of organic liquids and in water were investigated by means the replica method. There was more cross-sectional swelling of cell walls and cell wall thickness in earlywood than in latewood. Marked swelling toward cell lumens was observed in wood swollen in liquids that had higher swelling potentials than water. This suggests that the swelling of cell walls in these liquids is much greater than the external swelling. Feret's diameters of the cell lumens were reduced by swelling in all the observed cases except in the tangential direction of earlywood, suggesting that cell walls swell to a much less extent in width than in thickness. Deformation of cell shapes caused by the tensile force from the latewood were observed in the earlywood and in the transitional region from earlywood to latewood. When swollen in water, transverse swelling anisotropy caused only by the swelling in cell wall thickness were calculated to be 1.2 for the whole region over an annual ring and 1.4 for the earlywood. These values could not account for the external swelling anisotropy of 2.1. Considering obvious deformations of cell shapes in the earlywood and in the transitional region, we conclude that the interaction between earlywood and latewood is one of the prime factors contributing to the transverse swelling anisotropy of coniferous wood.Part of this report was presented at the 48th Annual Meeting of the Japan Wood Research Society, Nagoya, April 1998 相似文献
23.
Yutaka Kataoka Makoto Kiguchi Takeshi Fujiwara Philip D. Evans 《Journal of Wood Science》2005,51(5):531-536
Low density wood is more rapidly eroded than denser wood when exposed to the weather, possibly because it is more susceptible
to photodegradation. Fourier transform infrared microscopy was used to examine: (1) the depth of photodegradation in earlywood
and latewood of sugi (Japanese cedar) and earlywood of hinoki (Japanese cypress) exposed for up to 1500 h to artificial sunlight
emitted by a xenon lamp (375 W/m2 within the 300 to 700 nm spectral range); and (2) the relationship between the density of wood tissues and depth of photodegradation.
The depth of photodegradation varied between species (sugi and hinoki) as well as within a growth ring (sugi earlywood and
latewood), and there was an inversely proportional relationship between depth of photodegradation and wood density. These
findings may explain why low density earlywood is more rapidly eroded than latewood during weathering, and more generally,
why there is an inverse relationship between the density of wood species and their rate of erosion during artificial and natural
weathering.
Part of this work was presented at the 54th Annual Meeting of the Japan Wood Research Society, Sapporo, August 2004 相似文献
24.
Motoi Yasumura Takahisa Kamada Yutaka Imura Motoi Uesugi Laurent Daudeville 《Journal of Wood Science》2006,52(1):69-74
Pseudodynamic (PSD) tests were conducted on two-level timber structures with plywood-sheathed shear walls, which each had
an opening of different configuration, to study the effects of the mechanical properties of the first and second levels on
the earthquake response of the structure. The specimens had two-level conventional post and beam frames that were 3 m wide,
3 m deep, and 6 m high with plywood sheathings nailed on one face of the structure. The first and second levels had different
opening configurations of window, door, or slit. Lateral forces were applied at the top of the first and second levels, calculating
step by step the next displacement based on the North-South (NS) components of the 1940 El Centro earthquake. The test results
were compared with those of the time-history earthquake response analysis using the lumped mass model and hysteresis model
presented in the companion article (part I). The experimental and simulated results showed that the simulation by means of
the lumped mass time-history earthquake response analysis predicted quite well the response of the first level, but tended
to underestimate the response of the second level, and that the PSD tests of an individual wall system with the mass supported
by that particular wall generally show a conservative estimate of the response. 相似文献
25.
Based on paper of “Theoretical derivation of risk-ratios for assessing wind damage in coastal forest“,wind damage in the pine coasteal forest,which was thinned at four levels in December of 1997,was investigated for four successive growing seasons.Besides wind damage,the wind profiles outside and inside the coastal forest stand and the distributions of optical stratification porosity (OSP) were also observed.Based on these data,risk-ratios of wind damage for both individual trees and stands were estimated according to the methods developed in “Theoretical derivation of risk-ratios for assessing wind damage in a coastal forest“.The results showed that risk-ratios of wind damage,which were calculated from the meen height and diameter only and from the combination of wind and stand sructure profiles,accurately predicted wind damage in the plantation.Relationships between different thinning ratios and incidence of wind damage showed that stand stability decreased soon after the thinning.This was due to the immediate effects of thinning on increasing the canopy roughness and wind load,and on decreasing the sheltering effects from surrounding trees.However,thinning strategies could improve the stability by long-term effects on growthand development of trees against extreme wind.Only canopy damage was recorded during the experimental period,no stem damage was found,even though the maximum 10-min wind speed outside the coastal forest attained 30.2m s^-1.The results obtained in this study indicate that thinning is the most effective silvicultural strategy available for managing coastal forest despite the increased probability of wind damage soon after thinning. 相似文献
26.
Masahiro MIYABE Azusa GIN Eri ONOZAWA Mana DAIMON Hana YAMADA Hitomi ODA Akihiro MORI Yutaka MOMOTA Daigo AZAKAMI Ichiro YAMAMOTO Mariko MOCHIZUKI Toshinori SAKO Katsutoshi TAMURA Katsumi ISHIOKA 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》2015,77(10):1201-1206
G protein-coupled receptor (GPR) 120 is an unsaturated fatty acid receptor, which is
associated with various physiological functions. It is reported that the genetic variant
of GPR120, p.Arg270His, is detected more in obese people, and this genetic variation
functionally relates to obesity in humans. Obesity is a common nutritional disorder also
in dogs, but the genetic factors have not ever been identified in dogs. In this study, we
investigated the molecular structure of canine GPR120 and searched for candidate genetic
variants which may relate to obesity in dogs. Canine GPR120 was highly homologous to those
of other species, and seven transmembrane domains and two N-glycosylation sites were
conserved. GPR120 mRNA was expressed in lung, jejunum, ileum, colon, hypothalamus,
hippocampus, spinal cord, bone marrow, dermis and white adipose tissues in dogs, as those
in mice and humans. Genetic variants of GPR120 were explored in client-owned 141 dogs,
resulting in that 5 synonymous and 4 non-synonymous variants were found. The variant
c.595C>A (p.Pro199Thr) was found in 40 dogs, and the gene frequency was significantly
higher in dogs with higher body condition scores, i.e. 0.320 in BCS4–5 dogs, 0.175 in BCS3
dogs and 0.000 in BCS2 dogs. We conclude that c.595C>A (p.Pro199Thr) is a candidate
variant relating to obesity, which may be helpful for nutritional management of dogs. 相似文献
27.
Atsushi IDETA Yoshito AOYAGI Kanami TSUCHIYA Yuuki NAKAMURA Kou HAYAMA Atsushi SHIRASAWA Kenichiro SAKAGUCHI Naomi TOMINAGA Yoshiyuki NISHIMIYA Sakae TSUDA 《The Journal of reproduction and development》2015,61(1):1-6
Embryos obtained via superovulation are necessary for mammalian artificial reproduction, and viability is a key determinant of success. Nonfreezing storage at 4 C is possible, but currently used storage solutions can maintain embryo viability for only 24–48 h. Here we found that 10 mg/ml antifreeze protein (AFP) dissolved in culture medium 199 with 20% (v/v) fetal bovine serum and 25 mM HEPES could keep bovine embryos alive for 10 days at 4 C. We used a recombinant AFP isolated from the notched-fin eelpout (Zoarces elongatus Kner). Photomicroscopy indicated that the AFP–embryo interaction was enhanced at 37 C. Embryos pre-warmed with the AFP solution at 37 C for 60 min maintained high viability, whereas those that were not pre-warmed could live no longer than 7 days. Thus, short-term storage of bovine embryos was achieved by a combination of AFP-containing medium and controlled pre-warming. 相似文献
28.
Establishment of a Model of Spontaneously-Running-Tokushima-Shikoku Rats with Left Atrial Thrombosis
Takamasa Ohnishi Fumiko Hisaoka Masaki Morishima Akira Takahashi Nagakatsu Harada Kazuaki Mawatari Hidekazu Arai Emiko Yoshioka Satomi Toda Izumi Keisuke Yutaka Nakaya 《Journal of toxicologic pathology》2014,27(1):51-56
Studies that investigate the underlying mechanisms of disease and treatment options typically require the use of a suitable animal model. Few suitable animal models exist for left atrial thrombosis. Here, we demonstrated that the Spontaneously-Running-Tokushima-Shikoku (SPORTS) rat — a Wistar strain known for its running ability—is predisposed to the development of thrombi in the left atrium. We investigated the incidence of left atrial thrombosis in male (n = 16) and female (n = 17) SPORTS rats and observed organized atrial thrombosis in 57% and 38% of males and female rats, respectively. In the male rats, systolic blood pressures and heart rates were significantly higher in SPORTS rats than in control Wistar rats. We could not find any evidence of arrhythmias, such as atrial fibrillation, during electrocardiographic examination of SPORTS rats. We believe that the SPORTS rat could serve as a new research model for left atrial thrombosis; further, it may be suitable for research investigating the development of new antithrombotic approaches for the control of atrial thrombosis or familial thrombophilia in humans. 相似文献
29.
Misa HOSOE Nao YOSHIDA Yutaka HASHIYADA Hidetoshi TERAMOTO Toru TAKAHASHI Sueo NIIMURA 《The Journal of reproduction and development》2014,60(4):268-273
Fetal bovine serum (FBS) has been widely used as a supplement in the maturation medium of bovine oocytes in
vitro. However, serum contains many undefined factors and is potentially infectious to humans and animals. As a serum
replacement, we evaluated the feasibility of using the silk protein, sericin, derived from the cocoons of silkworm. To examine the
rates of oocyte maturation and fertilization, cumulus-oocyte complexes were cultured in TCM-199 supplemented with 0.01%, 0.05%,
0.1% or 0.15% sericin or 5% FBS. The sizes of the perivitelline space that might relate to polyspermy, the expressions of
Has2 and CD44 mRNA, the amount of hyaluronan (hyaluronic acid: HA) contained in the oocytes
and the rates of blastocyst formation following insemination were then compared between the oocytes cultured with 0.05% sericin
and 5% FBS, because the polyspermy rates in oocytes cultured with 0.05% sericin were significantly lower than in those cultured
with 5% FBS. After in vitro maturation (IVM), the mean size of the perivitelline space was significantly greater
in oocytes cultured with sericin than in those cultured with FBS, although the rates of nuclear maturation, fertilization and
blastocyst formation of oocytes under both IVM conditions were not significantly different. The expression of HAS2 and
CD44 mRNA and the amount of HA in the denuded oocytes cultured with 0.05% sericin were significantly greater than in
those cultured with FBS. These results indicate the feasibility of sericin as an alternative protein supplement for IVM in bovine
oocytes. 相似文献