Thermo characteristics of steam-exploded bamboo (Phyllostachys pubescens) lignin

Bamboo (Phyllostachys pubescens) internode was subjected to steam explosion treatment to produce an excellent fiber for binderless boards. Lignin was isolated from extract-free bamboo meal with Björkman’s procedure and steam-exploded pulp. The self binding-mechanism was discussed by scanning electron microscopy (SEM), thermo-gravimetry (TG), differential scanning calorimetry (DSC) and analytical ozonation. It is well-known that steam explosion treatment liberates lignin from the cell wall to the fiber surface, which is the most important component relevant to binderless board production. Results of TG and DSC analyses showed that steam-exploded bamboo pulp started mass loss at lower temperature compared to bamboo internode meal. The thermal softening temperature of lignin prepared from steam-exploded pulp was much lower than that of lignin prepared from extract-free bamboo meal. This suggests that intermonomer linkages of lignin, especially β-aryl-ether linkage which is the major intermonomer linkage of lignin, were cleaved during steam explosion treatment resulting in low molecular weight phenolic compounds. The cleavage of β-aryl-ether intermonomer linkage of lignin was also confirmed by ozonation analysis.     

Modelling the distribution of the pan‐continental invasive fish Pseudorasbora parva based on landscape features in the northern Kyushu Island,Japan

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Sooty spot of kiwifruit caused by Pseudocercospora actinidiae Deighton

Leaf spots on the lower leaf surface and sunken spots on the fruit of kiwifruit (Actinidia deliciosa and A. chinensis) were found in Fukuoka Prefecture, Japan. The observed fungus was identified as Pseudocercospora actinidiae Deighton. We propose the name sooty spot of kiwifruit (“susuhan-byo” in Japanese) as a new disease fullfilling Koch’s postulates.     

Identification of leptin gene polymorphisms associated with carcass traits and fatty acid composition in Japanese Black cattle

Previous studies have indicated that some leptin gene polymorphisms were associated with economically important traits in cattle breeds. However, polymorphisms in the leptin gene have not been reported thus far in Japanese Black cattle. Here, we aimed to identify the leptin gene polymorphisms which are associated with carcass traits and fatty acid composition in Japanese Black cattle. We sequenced the full‐length coding sequence of leptin gene for eight Japanese Black cattle. Sequence comparison revealed eight single nucleotide polymorphisms (SNPs). Three of these were predicted to cause amino acid substitutions: Y7F, R25C and A80V. Then, we genotyped these SNPs in two populations (JB1 with 560 animals and JB2 with 450 animals) and investigated the effects on the traits. Y7F in JB1 and A80V in JB2 were excluded from statistical analysis because the minor allele frequencies were low (< 0.1). Association analysis revealed that Y7F had a significant effect on the dressed carcass weight in JB2; R25C had a significant effect on C18:0 and C14:1 in JB1 and JB2, respectively; and A80V had a significant effect on C16:0, C16:1, C18:1, monounsaturated fatty acid and saturated fatty acid in JB1. The results suggested that these SNPs could be used as an effective marker for the improvement of Japanese Black cattle.     

Solute diffusion into cell walls in solution-impregnated wood under conditioning process III: effect of relative humidity schedule on solute diffusion into shrinking cell walls

This study has focused on solute diffusing into cell walls in solution-impregnated wood under conditioning, process of evaporating solvent. The purpose of this paper was to clarify the RH- (relative humidity-) schedule that promotes the solute diffusion into shrinking cell walls during conditioning. The wood samples impregnated with a 20 mass% aqueous solution of polyethylene glycol (PEG1540) was conditioned with a temperature of 40?°C to the equilibrium point at the RH where the samples swelled maximally. The samples were subsequently conditioned at 40?°C under the schedules including four ways of RH-decrease steps where the cell walls shrunk. The amount of solute (PEGs) diffused into cell walls during the conditioning logarithmically increased with increasing the number of the RH-decrease steps. This was well explained by the theoretical model that describes the solute diffusion into shrinking cell walls. It is clarified from the model that the RH, or moisture content of the sample, should be decreased as gradually as possible to increase the total amount of diffused solute into shrinking cell walls, and that the amount of diffused solute is smaller for the lower moisture content. The model also suggests that effect of change in RH schedule on change in total amount of diffused solute does not depend on solute diffusivity in the sample under drying in a vacuum over phosphorous pentoxide, and that impregnated wood should be conditioned under natural convection rather than forced convection for promoting the diffusion into shrinking cell walls.     

Utilization of sweet sorghum bagasse and citric acid for manufacturing of particleboard II: influences of pressing temperature and time on particleboard properties

Development of environmentally friendly particleboard made from sweet sorghum bagasse and citric acid has recently attracted attention. In this study, we investigated the effects of pressing temperature and time on physical properties, such as dry bending (DB), internal bond strength (IB), and thickness swelling (TS) of particleboard. Wet bending (WB), screw-holding power (SH), biological durability, and formaldehyde emission of particleboard manufactured under effective pressing temperature and time were also evaluated. Particleboards bonded with phenol formaldehyde (PF) resin and polymeric 4,4′-methylenediphenyl isocyanate (pMDI) were manufactured as references. Effective pressing temperature and time were 200?°C and 10 min, respectively. It was clarified that DB, IB, and TS satisfied the type 18 requirements of the JIS A 5908 (2003), and were comparable to those of particleboard bonded with PF and pMDI. The WB and SH of particleboard did not satisfy type 18 of JIS. Particleboard manufactured under effective pressing conditions had good biological durability and low formaldehyde emission. Based on the results of infrared spectra measurement, the degree of ester linkages increased with increased pressing temperature and time.     

Effect of high molecular weight carbohydrates on bud cell formation by <Emphasis Type="Italic">Fusarium oxysporum</Emphasis> in potato dextrose broth

Potato dextrose broth (PDB), one of the most popular culture media for fungi, can be made in the laboratory from potato extract and glucose (handmade PDB) and also bought as powder (commercial PDB). We compared growth of Fusarium oxysporum in handmade and commercial PDBs. For seven strains tested, bud cell formation and fungal biomass were higher in handmade PDB than in commercial PDB. Gel filtration analyses revealed that handmade PDB contained carbohydrates with molecular weights >20 MDa, while most carbohydrates in commercial PDB were <45 kDa. Freshly prepared, raw potato starch had a molecular weight >20 MDa and enhanced bud cell formation by five of seven strains when added to commercial PDB. The addition of glucose to commercial PDB promoted biomass production but not bud cell formation. Furthermore, in a semisynthetic medium containing raw potato starch, bud cell formation was enhanced for all strains tested. These results indicate that the high molecular carbohydrates present in raw potatoes enhanced bud cell formation by Fusarium oxysporum.     

Azimuthal variations of sap flux density within Japanese cypress xylem trunks and their effects on tree transpiration estimates

Sap flow techniques are practical tools for estimating tree transpiration. Though many previous studies using sap flow techniques did not consider azimuthal variations of sap flux density (F _d) on xylem trunk to estimate tree transpiration, a few studies reported that ignoring the azimuthal variations in F _d could cause large errors in tree transpiration estimates for some tree species. Therefore, examining azimuthal variations in F _d for major plantation tree species is critical for estimating tree transpiration. Using the thermal dissipation method, we examined azimuthal variations in F _d in six trees of Japanese cypress Chamaecyparis obtusa (Sieb. et Zucc.) Endl., which is one of the most common plantation tree species in Japan. We recorded considerable variations among F _d at four different azimuthal directions. The F _d value for one aspect was more than 100% larger than those for the other aspects. We calculated differences between tree transpiration estimates based on F _d for one to three azimuthal directions and those based on F _d for four aspects. The differences relative to tree transpiration estimates based on F _d for four aspects were typically 30, 20, and 10% in accordance with the F _d for one, two, and three measurement aspects, respectively. This finding indicates that ignoring azimuthal variations could cause large errors in tree transpiration estimates for Japanese cypress.     

Carbon nanotubes with temperature-invariant viscoelasticity from -196 degrees to 1000 degrees C

Viscoelasticity describes the ability of a material to possess both elasticity and viscosity. Viscoelastic materials, such as rubbers, possess a limited operational temperature range (for example, for silicone rubber it is -55° to 300°C), above which the material breaks down and below which the material undergoes a glass transition and hardens. We created a viscoelastic material composed from a random network of long interconnected carbon nanotubes that exhibited an operational temperature range from -196° to 1000°C. The storage and loss moduli, frequency stability, reversible deformation level, and fatigue resistance were invariant from -140° to 600°C. We interpret that the thermal stability stems from energy dissipation through the zipping and unzipping of carbon nanotubes at contacts.     

Effects of glucose and amino acids on ghrelin secretion in sheep

Two experiments were conducted to elucidate the effects of post‐ruminal administration of starch and casein (Exp. 1), plasma amino acids concentrations (Exp. 2), and plasma glucose and insulin concentrations (Exp. 2) on plasma ghrelin concentrations in sheep. In Exp. 1, plasma ghrelin concentrations were determined by four infusion treatments (water, cornstarch, casein and cornstarch plus casein) in four wethers. Abomasal infusion of casein increased plasma α‐amino N (AAN) concentrations. Infusion of starch or casein alone did not affect plasma ghrelin concentrations, but starch plus casein infusion increased plasma levels of ghrelin, glucose and AAN. In Exp 2, we investigated the effects of saline or amino acids on ghrelin secretion in four wethers. Two hours after the initiation of saline or amino acid infusion into the jugular vein, glucose was also continuously infused to investigate the effects of blood glucose and insulin by hyper‐glycemic clump on plasma ghrelin concentrations. Infusion of amino acids alone raised plasma levels of ghrelin, but the higher plasma glucose and insulin concentrations had no effect on plasma ghrelin concentrations. These results suggest that high plasma levels of amino acids can stimulate ghrelin secretion, but glucose and insulin do not affect ghrelin secretion in sheep.