A method for calculating the ratio of each possible type of triglyceride in natural fat

A generalized method for calculating the weight ratios or mole fractions of triglycerides in natural fat is developed by applying Vander Wal’s method for calculating the mole fractions. In the proposed method a generating function is introduced to calculate the mole fractions of triglycerides.     

Primary fibrosarcoma of the skull

The case of a 61-year-old woman with fibrosarcoma of the skull is discussed. Despite surgical treatment and irradiation, she died 23 months after diagnosis. Primary fibrosarcoma of the skull is rare but must be considered in the differentiation of the osteolytic lesions of the skull.     

Memory traps in MNOS diodes measured by thermally stimulated current

Thermally stimulated current was measured to determine trap distribution and charging and discharging mechanisms in a Metal-Nitride-Oxide-Semiconductor (MNOS) diode with 16 Å oxide thickness. By changing gate voltage, heating rate and the initial flat-band voltage, the memory traps near the nitride-oxide interface were separated from the others. The general formula was derived for the thermally stimulated current in an MNOS diode and was applied to obtain the trap distribution as well as effective emission time constants. The results indicate that the memory traps are distributed 50 Å deep into the nitride film from the nitride-oxide interface. The energy level lies at around 2·55 eV from the bottom of the nitride conduction band. The charging and discharging mechanism is the cascade connection of tunneling and thermal excitation or trapping. The obtained trap distribution and the charge transfer mechanism are successful for interpreting the write-in and retention characteristics.     

Low temperature aging of the freshly formed martensite in an Fe-Ni-C alloy

Aging regime, below and at room temperature, of the martensite formed in an Fe-24.67Ni-0.87C (mass pct) alloy (M _s = 160 K) is studied by using a poly crystalline X-ray diffraction technique. Parameters such as tetragonal axial ratio, unit cell volume, intensity ratios of the tetragonal doublet peaks,etc. are obtained for various degrees of aging. At temperature below ∼200 K, where the carbon atoms can shift only into their neighboring sites, the variation of the parameters indicates some discrepancies with the existing models. At room temperature, a new peak appears in between the tetragonal doublet peaks. This peak and the variation of the parameters at room temperature are explained in terms of carbon cluster formation. Formerly Graduate Student, Tottori University.     

‘Lipase and protease production of dairy Penicillium sp. on milk‐protein‐based solid substrates’

The lipolytic and proteolytic activity of Penicillium camemberti PC TT033 and Penicillium roqueforti PR G3, cultured on the whey solids or simulated cheese media, were compared under several pH reaction conditions. Lipolytic activity was higher when both strains had been cultured on the whey medium than on the simulated cheese medium, whereas proteolytic activity was less influenced by the culture medium. The relationship between the reaction pH and these enzyme activities was dependent on the culture medium, which suggested that the expression level and balance of isozyme rely on the culture substrate.     

Determination of potent odorants in apple by headspace gas dilution analysis

Gas chromatography-olfactometry with headspace gas dilution analysis was used to evaluate the odor potencies of volatile compounds in Fuji apple. To improve the resolution of volatile compounds, the dilution analysis was conducted on two types of capillary columns with different polarities. Thirty three and 20 compounds were identified on DB-WAX and DB-5 columns, respectively. Methyl 2-methylbutanoate, isobutyl acetate, ethyl butanoate, ethyl 2-methylbutanoate, isopentyl formate, butyl acetate and hexyl acetate as well as hexanal were important odor contributors in the headspace gas of apple on the basis of high Flavor Dilution (FD) factors. Threshold values-in-air of these compounds were also estimated from the relationships between their FD factors and concentrations. Methyl 2-methylbutanoate and ethyl 2-methylbutanote were considered as the most potent odorants because of their lowest threshold values. In addition, the threshold values-in-air of isopentyl formate, isopentyl acetate and butyl isobutanoate, which have never been reported, were estimated at 0.149, 1.95 and 0.00607 μl/l, respectively.     

Mechanisms of hydrogen sulfide removal with steel making slag

In the present study, we experimentally investigated the removal of hydrogen sulfide using steel-making slag (SMS) and clarified the mechanism of hydrogen sulfide removal with the SMS. The results proved that SMS is able to remove hydrogen sulfide dissolved in water, and the maximum removal amount of hydrogen sulfide per unit weight of the SMS for 8 days was estimated to be 37.5 mg S/g. The removal processes of hydrogen sulfide were not only adsorption onto the SMS, but oxidation and precipitation as sulfur. The chemical forms of sulfide adsorbed onto the SMS were estimated to be sulfur and manganese sulfide in the ratio of 81% and 19%, respectively. It is demonstrated here that the SMS is a promising material to remediate organically enriched coastal sediments in terms of removal of hydrogen sulfide. Furthermore, using SMS is expected to contribute to development of a recycling-oriented society.     

A comparative study of ethanol production by Issatchenkia orientalis strains under stress conditions

The ability of 13 strains of multi-stress-tolerant Issatchenkia orientalis yeast to produce ethanol was examined under different stress conditions, including conditions of elevated H₂SO₄ and Na₂SO₄ concentrations and increased heat. The MF-121 strain produced a significant amount of ethanol after the incubation in acidic media containing high concentrations of salt, e.g., 50 g/l Na₂SO₄ at pH 2.0, or at high temperatures, e.g., 43°C, when compared with other strains.