A sinusoidal PAM-PWM inverter

A new strategy, using both PAM (pulse amplitude modulation) and PWM (pulsewidth modulation) in combination for a power inverter is described. The output waveforms in the proposed PAM-PWM inverter are investigated both theoretically and experimentally. The line-to-line voltage waveform includes the fundamental component and the sidebands of the carrier frequency. Lower-order harmonics are not included in the output waveform. The amplitude of the fundamental component increases 15 percent more than that of a conventional sine-wave inverter. Since each inverter arm does not operate during two-thirds of the period, the heat generated in the devices is reduced, i.e., the size of the inverter system can be minimized because of the reduction in the heat dissipating equipment.     

Inhibitory Potency of Plant Antinutrients towards the In Vitro Digestibility of Buckwheat Protein

The inhibitory potency of dietary fiber sources, tannins, phytate, and a protein protease inhibitor on the in vitro pepsin-pancreatin digestibility of protein was compared. The protein inhibitor exhibited the highest inhibitory capacity among the substances examined; and phytate the lowest. Our findings suggest that the inhibition of the digestion of dietary sources of plant proteins by such factors as fiber and tannins, in addition to the protein protease inhibitors, may also be taken into account.     

Purification and Properties of Carp Muscle Cathepsin D

A carp muscle cathepsin was purified as an electrophoretically homogeneous preparation. The preparation represented about 2,000-fold purification and about 4% yield against the crude extract. The activity against hemoglobin was maximal at pH 2.6—2.8 with 0.6M buffer and near 3.2 with 0.12M buffer and at 50°C. The molecular weight was found to be 41,000 and the isoelectric point to be pH 5.4. From the effect of various inhibitors on the enzyme activity, the enzyme was identified as cathepsin D under the classification of Barret. Carp muscle cathepsin D hydrolyzed myofibrils optimally at pH 3–4, but did not above pH 6.0. The participation of the enzyme in autolysis is very doubtful.     

Kooroo color: 90-day dietary toxicity study in F344 rats

A subchronic toxicity study on kooroo color was conducted using F344 rats of both genders. Kooroo color is an extract of yam root, Dioscorea matudai Hayata, of which the major components are known to be flavonoid pigments. Use of kooroo as a food color is permitted by the Food Sanitation Law in Japan, but the chronic toxicity has not been evaluated in the literature. Rats were fed the product of kooroo color (PKC) at doses of 0.5%, 1.50%, and 5.0% in basal powder diet, while control groups received PKC-free basal diet, for ninety days. A vehicle control given propylene glycol (PG) alone, at the same dosage that the 5.0% group received, was included, because PKC used in this study contained ca. 80 percent PG, used as an extractant during the manufacturing processes. Daily observation of general behavior, and weekly measurement of body weight as well as food consumption were performed. Hematological, serum biochemical and anatomopathological examinations were conducted at the end of administration. No abnormalities ascribable to the treatment with PKC or PG were noted in any examination in this study. Hence, dietary intake of 5.0% of PKC, i.e., 2,993 mg/kg/day for males, and 3,376 mg/kg/day for females, as a mean daily intake for 90 days, had no observable adverse effect in F344 rats. Therefore, kooroo color has no significant general toxicity, and its toxicity, if any, is of a very low order.     

Normal spectral emittance of a nickel metal surface with rectangular microcavities

Spectral control of thermal radiation emitted from rectangular microcavities (0.5×0.5×0.5µm³) was investigated through emission experiments at high temperatures. The microcavities were fabricated on a mirror‐finished Ni metal surface. Through measurement of the normal spectral emittance, the maximum emittance was obtained around a wavelength of 0.87µm, which was very close to that (0.894µm) estimated from the cavity resonance theory. The emittance reached a maximum value of 0.95, and then decreased drastically with increasing wavelength, from the cut‐off wavelength. For a longer wavelength range from 1.7µm, it was equal to the emittance of the mirror‐finished surface. © 2009 Wiley Periodicals, Inc. Heat Trans Asian Res; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/htj.20248     

Understanding the mechanism of heat stress tolerance caused by high trehalose accumulation in Saccharomyces cerevisiae using DNA microarray

DNA microarray analysis was performed to examine the stress tolerance mechanism of a Saccharomyces cerevisiae recombinant strain exhibiting high trehalose accumulation and heat stress tolerance. Results suggest that the upregulation of sugar transporter genes is one of the key events for heat stress tolerance of the recombinant strain.