Identification of yeast strains isolated from marcha in Sikkim, a microbial starter for amylolytic fermentation

Marcha or murcha is a traditional amylolytic starter used to produce sweet-sour alcoholic drinks, commonly called jaanr in the Himalayan regions of India, Nepal, Bhutan, and Tibet (China). The aim of this study was to examine the microflora of marcha collected from Sikkim in India, focusing on yeast flora and their roles. Twenty yeast strains were isolated from six samples of marcha and identified by genetic and phenotypic methods. They were first classified into four groups (Group I, II, III, and IV) based on physiological features using an API test. Phylogenetic, morphological, and physiological characterization identified the isolates as Saccharomyces bayanus (Group I); Candida glabrata (Group II); Pichia anomala (Group III); and Saccharomycopsis fibuligera, Saccharomycopsis capsularis, and Pichia burtonii (Group IV). Among them, the Group I, II, and III strains produced ethanol. The isolates of Group IV had high amylolytic activity. Because all marcha samples tested contained both starch degraders and ethanol producers, it was hypothesized that all four groups of yeast (Group I, II, III, and IV) contribute to starch-based alcohol fermentation.     

Intermittent administration of brain-derived neurotrophic factor (BDNF) ameliorates glucose metabolism and prevents pancreatic exhaustion in diabetic mice

We previously demonstrated that repetitive administration of brain-derived neurotrophic factor (BDNF) ameliorates glucose metabolism and energy expenditure in obese diabetic db/db mice. However, we have not evaluated in detail the effect of single or intermittent BDNF administration on glucose metabolism in a diabetic animal model. The objectives of this study were to examine the dose-response effect and dosing interval of BDNF administration in db/db mice and to evaluate the effect of intermittent BDNF administration on pancreatic function in db/db mice. We evaluated the dose-response effect of BDNF by single administration in db/db mice. First, single administration of BDNF greater than 70 mg/kg significantly reduced blood glucose concentration one day after administered, and the BDNF effect was maintained for 6 d. Next, the effects of BDNF administered twice a week at 4, 10, 25, and 62.5 mg/kg on blood glucose concentration, and the effects of BDNF administered once a week at 10, 20, 30, 50, and 70 mg/kg on blood glucose concentration were examined in db/db mice. In the intermittent treatment studies, BDNF dose-dependently ameliorated glucose metabolism by not only the twice-a-week administration but also the once-a-week administration. Lastly, because BDNF reduces the food intake of obese hyperphagic diabetic mice, the effects of BDNF administered once or twice a week on the blood glucose concentration and plasma and pancreatic insulin concentrations in db/db mice were compared with those of the vehicle under pair-fed conditions. Under pair-fed conditions, the intermittent administration of BDNF (25 mg/kg, twice a week, or 50 mg/kg, once a week) significantly reduced the blood glucose concentration and increased the plasma and pancreatic insulin concentrations compared with those in the pair-fed vehicle-treated db/db mice. This indicates that the prolonged hypoglycemic effect of BDNF is not simply due to the reduction of food intake. In conclusion, we demonstrated that the intermittent administration of BDNF ameliorates glucose metabolism and prevents pancreatic exhaustion in obese diabetic mice. These findings indicate that BDNF may have potential as a unique hypoglycemic agent for the treatment of diabetes at a fundamental level with good patient compliance.     

Physicochemical characteristics of rapidly dried onion powder and its anti-atherogenic effect on rats fed high-fat diet

Rapidly dried onion (Allium cepa L. cv. Momiji No. 3) powder (OP) prepared from the outer layers (from second to fourth scale leaves from the surface) of onion bulbs was analysed for its quercetin and polyuronide contents, the effects of enzymatic treatment and the anti-atherogenic effect on rats fed a high-fat diet. Quercetin 4′-glucoside (50%), free quercetin (30%) and quercetin 3,4′-diglucoside (20%) were identified as quercetin derivatives, and boiling-water extraction was effective in extracting these compounds. OP contained 12.9% of polyuronides, the basic skeleton of pectin. Enzymatic degradation (cellulase and pectinase, 50 °C for 12 h, pH 6.0) of OP was effective in obtaining a slurry of smaller particle sizes. The free quercetin increased and the glucosides decreased with enzyme treatment. In Wistar rats fed an OP-added high-fat diet, the total cholesterol, HDL-cholesterol and triglyceride concentrations were not significantly different from the rats fed a high-fat diet without OP. However, the atherogenic index (AI) of Wistar rats fed an OP-added high-fat diet was lower (AI = 3.3) than rats fed the diet without OP (AI = 4.1). The incremental elastic modulus (IEM) of the aorta from rats fed the OP-added diet was also significantly lower than that of the rats fed the diet without OP. The AI and IEM values of the rats fed the OP-added diet were quite similar to the values of rats fed the diet without OP but were allowed spontaneous exercise. These results suggest that OP intake is effective for decreasing the risk of arteriosclerosis.     

Re-evaluation of the phase relationship between plutonium and zirconium dioxides

The phase relationship between ZrO₂ and PuO₂ was examined in a low PuO₂ content region, from 3.1 to 11.2 mol% PuO₂, at temperatures between 1273 K and 1473 K, by high temperature X-ray diffractometry. The measurements were carried out in air. At 1273 K, the samples in this composition range consisted of two phases, monoclinic and cubic. Another phase, tetragonal, was observed at 1373 K. The low temperature monoclinic phase disappeared at 1473 K. It was confirmed that the monoclinic phase disappears around 1463 K; the disappearance temperature does not depend on the composition of the sample. It was, thus, inferred that there should be a eutectoid line in the phase diagram. Though the eutectoid point is not clear, the PuO₂ content at the point should be less than 3.1 mol%.     

Effect of filler concentration on electrical conductivity andultralow-frequency dielectric properties

The effect of filler concentration on the dielectric properties in the ultralow-frequency region and on the electrical conductivity was studied for ethylene propylene rubber. First, we investigated the relation between the electrical conductivity and filler concentration: as the volume fraction of fillers q_a increased, the conductivity decreased in the low filler concentration region but increased abruptly in the high filler concentration region. The decrease and increase in conductivity can be explained with the action of carrier traps at the interface between EPR and fillers and with the formation of highly conductive paths of filler across the sample, respectively. Secondly, we studied the dielectric properties in the ultralow-frequency region which was obtained from the discharge current. As q_a increased, the relaxation time decreased in the low filler concentration region and then rose in the high filler concentration region. The polarization in the high filler concentration region can be explained by two-layer interfacial polarization between filler and rubber     

Very high characteristic temperature and constant differentialquantum efficiency 1.3-μm GaInAsP-InP strained-layer quantum-welllasers by use of temperature dependent reflectivity (TDR) mirror

A very high characteristic temperature T₀ of 150 K (25-70°C) or 450 K (25-50°C) and an almost constant differential quantum efficiency operation in the temperature range of 25-70°C were achieved in 1.3-μm GaInAsP-InP strained-layer quantum-well (SL-QW) lasers by use of a novel temperature dependent reflectivity (TDR) mirror composed of multiple quarter-lambda thickness α-Si-SiOx dielectric films with quarter-lambda shift in the vicinity of center portion, The mechanism of high T₀ and constant differential quantum efficiency were explained using the structural parameters, transparent current density and gain coefficient of a SL-QW laser that are derived experimentally. The effect of TDR mirror was confirmed by measuring the temperature dependence of net gain of a SL-QW laser with TDR mirror. It was found that less temperature dependent net gain due to the decrease of mirror loss with temperature played an important role for improving the temperature characteristics of threshold current. Almost constant differential quantum efficiency over a wide temperature range is attributed to the increase of the facet reflectivity with temperature     

Production of thin graphite sheets for a high electrical conductivity film by the mechanical delamination of ternary graphite intercalation compounds

Herein we propose a production scheme for conductive films composed of thin graphite sheets with high crystallinity and polymeric resin. The crystalline graphite sheets were successfully produced from natural graphite powder by solution-phase synthesis of graphite intercalation compounds (GICs), following a wet planetary-ball milling under mild conditions. The shear forces in the milling pot lead to a peeling of graphite flakes. Taking into consideration the interlayer bonding force, the delamination should be preferentially done from the expanded GICs interlayer rather than intrinsic graphite one. Some composite films derived from the phenolic resin and flaky graphite sheets displayed much higher electrical conductivities compared to the film from the feed graphite particles. We also demonstrate the stage structure of synthetic GICs affected the film conductivity. The composite films made from exfoliated products of ground (around stage IV) GICs exhibited high electrical conductivity with a small amount of the graphite sheets.     

Thermal strain of high strength polyethylene fiber in low temperature

High strength polyethylene fiber (Toyobo, Dyneema® fiber: hereinafter abbreviated to DF) has a negative thermal expansion coefficient. Relation between fiber structure and thermal strain of DF used as reinforcement of DF reinforced plastic (DFRP) for cryogenic use was investigated. The crystallinities and orientation angles of several kinds of polyethylene fibers having different modulus from 15 to 134Gpa (herein after abbreviated to DFs) were measured by NMR and X‐ray. We obtained the parameters of the mechanical series‐parallel model composed of crystal and amorphous by crystallinity and modulus. Thermal expansion coefficients of DFs were estimated by mechanical series‐parallel model. All DFs having different modulus showed negative thermal expansion coefficients in the temperature range from 180 to 300K, and absolute values of those markedly increased by increasing tensile modulus of DF. The estimated thermal expansion coefficients showed negative values, and thermal strains showed a similar curve to observed ones mostly. Average thermal expansion coefficients in the temperature range from 180 to 300K estimated by mechanical model agreed with the observed ones. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 2918–2925, 2004