Transcriptional and translational analyses of poplar anionic peroxidase isoenzymes     

Shinya Sasaki  Motoyuki Shimizu  Hiroyuki Wariishi  Yuji Tsutsumi  Ryuichiro Kondo 《Journal of Wood Science》2007,53(5):427-435

  相似文献   

Dielectric relaxation due to heterogeneous structure in moist wood     

Hiroyuki Sugimoto  Ryosuke Takazawa  Misato Norimoto 《Journal of Wood Science》2005,51(6):549-553

Dielectric properties in three main directions for hinoki wood (Chamaecyparis obtusa) specimens conditioned at various levels of relative humidity were measured in the frequency range from 20 Hz to 10 MHz over the temperature range from −150°C to 20°C. Three relaxations were observed in the specimens conditioned at high levels of relative humidity. The relaxation in the highest frequency range was ascribed to the motions of adsorbed water molecules. The relaxation in the middle frequency range remained unchanged by the ethanol–benzene extraction of specimens. The relaxation location was independent of measuring directions. The relaxation in the lowest frequency range was not detected in the specimens impregnated with methyl methacrylate (MMA). This result suggested that the relaxation was due to electrode polarization. The Cole-Cole circular arc law applied well to two relaxations recognized in the specimens impregnated with MMA. The relaxation magnitude in the middle frequency range was extremely large, and the distribution of relaxation times was very narrow. These characteristics suggested relaxation of the Maxwell-Wagner type resulting from the interfacial polarization in the heterogeneous structure, which included adsorbed water with large electrical conductivity within the insulating cell walls.  相似文献   

Mechanical behavior of the crystal lattice of natural cellulose in wood under repeated uniaxial tension stress in the fiber direction     

Takahisa Nakai  Hiroyuki Yamamoto  Tetsuya Nakao  Masatoshi Hamatake 《Wood Science and Technology》2006,40(8):683-695

This study investigated the relationship between the cellulose crystal lattice strain (crystalline region) and the macroscopic surface strain in specimens of Chamaecyparis obtusa wood under repeated uniaxial tension stress in the fiber direction. Changes in the strain of the crystal lattice were measured from the peak of (004) reflection using the transit X-ray method. The macroscopic surface strain of each specimen was measured with a strain gauge. In both loading and unloading, the surface strain changed linearly with changes in stress. However, crystal lattice strain was not linear but exhibited changes along a curve with changing stress. Under stressed conditions, the crystal lattice strain was always less than the surface strain, regardless of the frequency of repetition in the loading and unloading cycle. The ratio of the crystal lattice strain to the surface strain showed a negative correlation for stress in both loading and unloading. That is, the ratio decreased with increasing stress, and finally tend to converge to a specific value. The ratio (I/I ₀) between the diffracted intensity (I ₀) in the (004) plane in the unloaded condition and the diffracted intensity (I) in the (004) plane in the loaded condition tend to converge on a specific value with increasing frequency of repetition. When the substantial tension Young’s modulus of the wood in the longitudinal direction decreased, the ratio of the strain of the crystal lattice to the surface strain also decreased. Moreover, the ratio decreased with increasing microfibril angle of the specimen.  相似文献   

Effects of light and microsite conditions on tree size of 6-year-old Cryptomeria japonica planted in a group selection opening     

Toru Kohama  Nobuya Mizoue  Satoshi Ito  Akio Inoue  Kotaro Sakuta  Hiroyuki Okada 《Journal of Forest Research》2006,11(4):235-242

We examined the extent to which direct and indirect measures of light and microsite conditions could explain variation in tree height and diameter at the base of 6-year-old Cryptomeria japonica trees planted in a group selection opening of about 0.32 ha on a steep slope at Shiiba, Miyazaki Prefecture, southern Japan. We first used the gap light index (GLI) and soil thickness (ST) as directly measured indices. For an indirect measure of light, we used a between-cohort competition index (BCI) estimated from the position and total height of residual trees. For indirect measures of microsite, we examined topographic indices (slope, plan and profile curvature, average slope gradient, and relative elevation) derived from digital elevation models (DEMs) with different resolutions ranging from 2 to 10 m. The multiple linear regression using GLI and ST explained about 45% of variation in tree size, while simple regression using only GLI explained about 35%. The contribution of ST was about half of GLI. The multiple regressions using BCI and the topographic indices did not explain any more variation than using BCI alone (R ² of about 0.26). We conclude that microsite conditions with shallower soil and steeper slope have negative effects on tree growth in group selection openings, although the relative importance is smaller than light conditions. More comprehensive studies considering several openings with more heterogeneous topography including different species are needed to generalize our growth prediction using the indirect measures, which are useful for practical forest management.  相似文献   

Compressive deformation of wood impregnated with low molecular weight phenol formaldehyde (PF) resin II: effects of processing parameters   总被引：1，自引：0，他引：1  

Md Iftekhar?ShamsEmail author  Hiroyuki?Yano 《Journal of Wood Science》2004,50(4):343-350

To obtain high-strength phenol formaldehyde (PF) resin-impregnated compressed wood at low pressing pressure, the effects of resin content, preheating temperature, pressing temperature, and pressing speed on the compressive deformation of oven-dried low molecular weight PF resin-impregnated wood was investigated. With an increase of PF resin content, the Youngs modulus of the cell wall perpendicular to the fiber direction decreases, and collapse-initiating pressure decreases linearly with the Youngs modulus. This indicates that the occurrence of cell wall collapse is strain-dependent. By increasing preheating temperatures, the collapse-initiating pressure increases due to the increment of the Youngs modulus of the cell wall. An increase in pressing temperature results in the thermal softening of the cell wall and causes collapse at a lower pressure. The wood is compressed effectively despite accelerated resin curing. The pressing speed significantly affects the viscoelastic deformation of the cell wall and the wood is well deformed with decreasing pressing speed, although the differences in density and mechanical properties are relatively small after a pressure-holding period of 30min. In all the parameters examined in this study, the Youngs modulus and bending strength increase with increasing density.  相似文献   

Condensation reactions of phenolic resins V: cure-acceleration effects of propylene carbonate     

Naruyuki?Kamo  Hiroyuki?Okamura  Mitsuo?Higuchi  Mitsuhiro?MoritaEmail author 《Journal of Wood Science》2004,50(3):236-241

Propylene carbonate (PC) is known as one of the cure accelerators for alkaline phenol–formaldehyde resins. To elucidate the cure-acceleration mechanisms, the effects of PC on the condensation reactions of monomeric hydroxymethylphenols (HMPs) were investigated and compared with those of PC hydrolysate, sodium bicarbonate (NaHCO₃) and ethyl formate. Immediately after the reaction started, PC, decomposing itself simultaneously, accelerated the formation of the ortho-para methylene-bonded dimer of 2,4,6-trihydroxymethylphenol. This effect of PC was very similar to that of ethyl formate. To the contrary, PC hydrolysate accelerated the formation of the para-para methylene-bonded dimer throughout the course of the reaction. This effect of PC hydrolysate was identical to that of NaHCO₃. These results indicate that PC increases the reactivity of the ortho-hydroxymethyl group, presumably through transesterification. On the other hand, NaHCO₃ is formed by the hydrolysis of PC or decomposition of the transesterified HMPs and it increases the reactivity of the para-hydroxymethyl group.  相似文献   

Pilot Study to Examine Radial Variation in Annual Ring Width, Density and Shrinkage     

URAKAMI Hiroyuki  HIRAKAWA Yasuhiko  YAMASHITA Kana 《中国林业科技(英文版)》2003,(4)

The annual ring width, density and shrinkage variation from pith to bark in Chinese fir (Cunninghamia lanceolata) and Boka sugi (Cryptomeria japonicd) were studied and compared. The results show that the ring width decreased sharply from pith to bark for Chinese fir. However, the ring width variation pattern for Boka sugi followed a different way, i.e., the ring width decreased to the fifth ring, increased to the tenth ring, decreased again to the fifteenth, and then increased to the twentieth, where it became constant. The large variations of Boka sugi appeared to show the maintenance of fast growth for many years. The annual ring mean density of Chinese fir increased gradually from pith to bark. However, the density changes for Boka sugi indicated the opposite trend, i.e., the mean density decreased gradually from pith to bark. The former showed a pattern as the same as a pine and a larch, and the latter was often found in a cedar and a cypress. The longitudinal shrinkage in juvenile wood was much hig  相似文献   

Continuum contraction of tension wood fiber induced by repetitive hygrothermal treatment     

Sujan  KC  Yamamoto  Hiroyuki  Matsuo  Miyuki  Yoshida  Masato  Naito  Kazuhiro  Shirai  Tatsuya 《Wood Science and Technology》2015,49(6):1157-1169

Wood Science and Technology - Tension wood, when kiln-dried, is likely to deform hugely, which is probably caused by a gelatinous layer of the gelatinous fiber. To elucidate the mechanism behind...  相似文献   

Nutrient starvation affects expression of LC3 family at the feto-maternal interface during murine placentation     

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   

Na?ve-like conversion enhances the difference in innate in vitro differentiation capacity between rabbit ES cells and iPS cells     

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