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51.
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
52.
Subyakto Toshimitsu?Hata Isamu?Ide Takeshi?Yamane Shuichi?KawaiEmail author 《Journal of Wood Science》2004,50(2):157-161
Laminated veneer lumber joints made with metal plate connectors were protected with wood carbon phenolic spheres (CPS) sheeting and tested for creep under fire. The effects of the carbonizing temperature of charcoal, used as raw material for the CPS sheets, the thickness, and the location of the sheet on the joint regarding the fire-resistance performance of the joint were studied. The time to rupture of the joints covered with CPS sheets made from charcoal carbonized at 800°C (CPS800) was slightly prolonged compared with that of uncovered joints. On the other hand, the time to rupture of CPS sheets made from charcoal carbonized at 1600°C (CPS1600) was markedly extended. The changes in the charcoal properties due to increasing the carbonizing temperature might be the main reason the CPS1600 sheets had higher fire-resistance performance. The thickness and location of CPS1600 sheets have significant effects on the fire resistance of the joint. A highly fire-resistant laminated veneer lumber joint was obtained using a CPS1600 sheet. The CPS1600 sheet with a thickness of 3mm covering three sides of the joint prolonged the time to rupture 16-fold compared with that of unprotected joints.Part of this paper was presented at the 4th International Wood Science Symposium, Serpong, Indonesia, September 2002 相似文献
53.
1-Hydroxyethyl-2-alkyl-2-imidazoline (HEAI) and its derivative sulfonate amphoteric surfactant were synthesized using tall oil fatty acid as the raw material. Suitable experimental conditions for synthesizing the intermediate and final products were probed. Their chemical structures were also investigated by means of infrared spectroscopy and hydrogen nuclear magnetic resonance spectroscopy. Based on the results of these analyses, it has been found that during the reaction process of HEAI with sodium 3-chloro-2-hydroxypropane sulfonate under alkaline condition the imidazoline ring was hydrolyzed to amides, and the obtained amphoteric surfactant was actually a complex mixture of amides. An etherification reaction in the hydroxyethyl group was also observed when the HEAI/sodium 3-chloro-2-hydroxypropane sulfonate molar ratio was more than 1:1. 相似文献
54.
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
55.
农田防护林主要间距离的确定——基于林带结构与风速降低的关系 总被引:3,自引:0,他引:3
Relative windspeed reduction was measured behind nine relatively narrow, homogenous tree windbreaks with porosities between
0.13–0.33, and behind 28 combinations of model stubble barriers representing 25 different optical porosities (0.00–0.80).
The optimum porosities observed were 0.25 and 0.13 for tree windbreaks and stubble barriers respectively. Based on the relationship
between windbreak structure (optical porosity) and wind reduction, the chief indices for determining spacing interval, i.e.,
the windbreak structure index (δ) and the parameter of microclimate, represented by the problem wind (L
rp
), were determined. Additionally, investigations on shelterbelt trees were carried out, and stem-analysis techniques were
used, to develop a method for determining the mature height of tree windbreaks (H
0). Optimal spacing intervals between windbreaks could be predicted from the indices of a given windbreak structure, percentage
of reduction of windspeed desired and tree growth model. A hypothetical example for determining the spacing interval of principal
poplar windbreaks is given at the end of this paper. The results can be applied not only to tree windbreak design but also
to other plant materials and artificial barriers for wind protection.
Foundation item: This study was supported by Innovation Research Project of Chinese Academy of Sciences
Biography: ZHU Jiao-jun (1965-), male, Ph. Doctor, PhD advisor. Professor of Institute of Applied Ecology, the Chinese Academy of Sciences,
China, Scholar researcher of Faculty of Agriculture, Niigata University, Japan.
Responsible editor: Song Funan 相似文献
56.
Masato HIYAMA Ken Takeshi KUSAKABE Ai TAKESHITA Sinji SUGI Nobue KUNIYOSHI Hiroyuki IMAI Kiyoshi KANO Yasuo KISO 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》2015,77(3):305-311
LC3 − the mammalian homolog of Atg8 − was found as autophagosome membrane binding protein
in mammals and widely used as an autophagosomal marker. LC3A, B and C show different
expression patterns in each tissue. The aim of this study was to reveal the differences of
expression patterns among LC3 families in mouse placenta under normal condition and
nutrient starving condition. LC3A and B were highly expressed in decidual cells. LC3A and
B were increased in D14 compared with D12 and D16 in mouse placenta, while LC3C was
decreased. Starvation induced increase in LC3B expression specifically.
Immunohistochemistry showed different expression patterns among LC3A, B and C. LC3A
expression in syncytiotrophoblast was vanished by starvation. The results of real time
RT-PCR suggested differences between D12 and D16 in autophagic cascade induced by
starvation. Taken together, this study suggests that autophagy could play a role in
placental invasion system and that nutrient starvation affects LC3B expression. 相似文献
57.
Bhuminad DEVKOTA Masahiro TAKAHASHI Saori SATO Kouya SASAKI Atsushi UEKI Takeshi OSAWA Masahiro TAKAHASHI Norio YAMAGISHI 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》2015,77(7):875-878
Blood samples were obtained sequentially from 10 dairy cows around the time of
parturition to assess plasma fluctuations in estradiol-17β (E2) levels in
association with those of several bone resorption markers. Plasma E2
concentration increased sharply a few days prepartum and decreased quickly after
parturition. In terms of bone resorption markers, the plasma level of tartrate-resistant
acid phosphatase isoform 5b (TRAP5b) rose significantly, commencing 1 week prepartum, and
was maintained at this level to a few days postpartum. The plasma concentration of
carboxyterminal collagen cross-links of type-I collagen (CTx) increased significantly
after parturition. These observations suggest that osteoclast-mediated bone resorption was
activated after parturition when plasma E2 concentrations decreased. 相似文献
58.
Kimiko HONSHO Michiko HIROSE Masanori HATORI Lubna YASMIN Haruna IZU Shogo MATOBA Sumie TOGAYACHI Hiroyuki MIYOSHI Tadashi SANKAI Atsuo OGURA Arata HONDA 《The Journal of reproduction and development》2015,61(1):13-19
Quality evaluation of pluripotent stem cells using appropriate animal models needs to be improved for human regenerative medicine. Previously, we demonstrated that although the in vitro neural differentiating capacity of rabbit induced pluripotent stem cells (iPSCs) can be mitigated by improving their baseline level of pluripotency, i.e., by converting them into the so-called “naïve-like” state, the effect after such conversion of rabbit embryonic stem cells (ESCs) remains to be elucidated. Here we found that naïve-like conversion enhanced the differences in innate in vitro differentiation capacity between ESCs and iPSCs. Naïve-like rabbit ESCs exhibited several features indicating pluripotency, including the capacity for teratoma formation. They differentiated into mature oligodendrocytes much more effectively (3.3–7.2 times) than naïve-like iPSCs. This suggests an inherent variation in differentiation potential in
vitro among PSC lines. When naïve-like ESCs were injected into preimplantation rabbit embryos, although they contributed efficiently to forming the inner cell mass of blastocysts, no chimeric pups were obtained. Thus, in vitro neural differentiation following naïve-like conversion is a promising option for determining the quality of PSCs without the need to demonstrate chimeric contribution. These results provide an opportunity to evaluate which pluripotent stem cells or treatments are best suited for therapeutic use. 相似文献
59.
Takeshi OHTA Shuichi KIMURA Masaya HIRATA Takahisa YAMADA Toshie SUGIYAMA 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》2015,77(10):1327-1330
The Spontaneously Diabetic Torii (SDT) fatty rat, a model for obese type 2 diabetes,
shows bone quantitative abnormalities, namely low bone mineral density (BMD). The
objective of this study was to evaluate bone morphological changes, in particular
identifying the bone qualitative abnormalities, in the SDT fatty rat. Male SDT fatty rats
showed increases in total trabecular area and trabecular number and decreases in
trabecular thickness in cancellous bones of the proximal tibia, indicating trabecular
miniaturization. The SDT fatty rat is useful for investigation of pathophysiological
changes in bone quality in diabetic osteoporosis. 相似文献
60.
Neoh TL Yamauchi K Yoshii H Furuta T 《Journal of agricultural and food chemistry》2007,55(26):11020-11026
1-methylcyclopropene (1-MCP), an ethylene inhibiting regulator, is commercially available in the form of an inclusion complex with alpha-cyclodextrin (alpha-CD). In this study, molecular encapsulation of gaseous 1-MCP into aqueous alpha-CD was investigated in a closed, agitated vessel with a flat gas-liquid interface. Molecular encapsulation of gaseous 1-MCP by alpha-CD is a simultaneous two-step reaction which involves the aqueous dissolution of gaseous 1-MCP and the encapsulation of the dissolved molecules by alpha-CD. The kinetics and mechanism of molecular encapsulation were analyzed based on the depletion rate of 1-MCP in the headspace of the vessel. The encapsulation rates could be explained quantitatively by the gas absorption theory with a pseudo-first-order reaction between 1-MCP and alpha-CD. The negative value of the calculated apparent activation energy of encapsulation (-24.4 kJ/mol) implied the significant effect of exothermic aqueous dissolution of 1-MCP. An encapsulation temperature of 15 degrees C was optimal; at this temperature, the highest 1-MCP yield and best inclusion ratio of inclusion complex were obtained. Changes in the X-ray diffraction pattern suggested that the crystal lattice structure of alpha-CD was altered upon inclusion of 1-MCP. 相似文献