V. parahaemolyticus possessed an extracellular alkaline protease activity during the stationary growth phase. Various factors such as initial pH of medium, incubation temperature and shaking rate were investigated for optimizing the production of allcaline protease from V. parahaemolyticus ATCC 17802. Maximal activity of the protease was obtained when the bacteria were grown in 2% skim milk medium in 0.1 M tris/HCl buffer (pH 7.6). Maximal activity of the protease was obtained when the bacteria were grown at initial pH of 7.6, incubation temperature of 37℃ and shaking rate of 250 rpm.

Agarooligosaccharides were produced by β-agarase from Bacillus cereus ASK 202. LD_(50) of Agarooligosaccharides was determined to be 1359 mg/kg which corresponded to GRAS material. Agarooligosaccharides at 5% level exhibited 88.3% inhibition on TA98 and 54% on TA100, indicating agarooligosaccharides to be potent antimutagenic substance. Immunologic activity of agarooligosaccharides was also confirmed by mouse spleen cell culture. Agarooligosaccharides addition of 200 ㎕/ml stabilized spleen cells (2.5 × 10^6 cells/ml) as compared to control (6.4 × 10⁴ cells/ml).

Agar, one of the most abundant marine products has not been utilized extensively because of low level of processing technology in Korea. This research was carried out to improve the utilization of agar and consequent increase in profit. Antibacterial activity of agarooligosaccharides were evaluated against bacteria causing putrefaction and food poisoning. Addition of 0.4% agarooligosaccharides showed antibacterial activity toward Staphylococcus aureus and Escherichia coli O157:H7; furthermore, autoclave treatment of agarooligosaccharides solution enhanced the antibacterial activity. Agarooligosaccharides showed high stability against the pH change. Addition of amino acid(alanine, lysine, glycine, phenylalanine) in agarooligosaccharides solution enhanced antibacterial activity in E. coli O157:H7, Streptococcus mutans and Staphylococcus aureus.

Al2O3SiC particle was prepared was prepared by the self-propagting high temperature sYthesis(SHS) process from a mixture of SiO2, Al and C powders, The fabricated Al2O3SiC particle was applied to 2024Al/(Al2O3SiC)pcomposite as a reinforcement. Aluminum matix composites were fabricares by the powder extrusion method using the synthesized Al2O3SiC particle and commercial 2024Al powder. Theoptimum preparation conditions for Al2O3SiC partticle by SHS process were described. The influence of the Al2O3SiC voiume fraction on the mechanical was composite was also discussed. Despite adiabatic temperature was about 2367K, SHs reaction was completed not by itself, but by using pre-heating. Mean particle size of final particle synthesized was 0.73 m and most of the particle was smaller than 2m. Elastic modulus and tensile strength of the composite increased with increase the volume fraction of reinforcement but, tensile strength depreciated at 30 vol% of reinforcement.

침엽수와 활엽수 펄프내의 리그닌(lignin) 제거 효과를 개선하기 위해 호알칼리성 균류인 Cephalospotium sp. RYM-202의 xylanase를 표백 전처리하고 이에 의한 펄프의 표백 증진 효과를 조사하였다. 두 종류의 펄프 모두 50℃에서 효소반응을 수행하였을 때 펄프내 xylan의 가수분해가 가장 높게 나타났다. 펄프내 xylan의 가수분해를 위한 효소의 최적 pH는 8.0이었으며, pH 9.0에서도 최대활성의 90%

We have studied the IR properties of molecular clouds in the region of the supershell GS234-02 using IRAS and COBE data. The mean values of dust color temperature and optical depth at 240μm are derived to be 15.4±1.5 K and 9.0±5.7×10-4, respectively, which agree well with those determined by Sodroski et al.(1994) for the outer Galaxy. Mean IRAS colors, R12/100= 0.074, R25/100= 0.052, R60/100= 0.219, indicate that the abundance of PAHs is enhanced but other particles are nearly the same as those of the solar neighborhood. We found the anticorrelation between R100/140 and R140/240. It cannot be explained by the thermal emission of traditional big grains. The anticorrelation implies that, at high ISRF, T100/140 underestimates the equilibrium temperature, while T140/240 overestimates it and, at low ISRF, vice versa. Therefore we propose to use the intensity ratio, R100/240 as a dust thermometer.

The role of cytochrome P-450 2E1 (P450 2E1) in the early phase of alcoholic fatty liver was examined. Female rats were pretreated with either allyl sulfide (200 mg/kg, po), disulfiram (500 mg/kg, po), YH 439 (250 mg/kg, po) or pyrazine (200 mg/kg/day × 2 days, ip). Marked changes in carbon tetrachloride-induced hepatotoxicity and carboxyhemoglobin (COHb) elevation due to dichloromethane administration were observed in rats treated with one of the P450 2E1 modulators. A single dose of ethanol (6 g/kg, po) increased the hepatic triglyceride contents approximately 2 fold, which was inhibited completely by YH 439 pretreatment. However, the other P450 2E1 modulators failed to alter the ethanol-induced hepatic triglyceride accumulation. In vitro hepatic microsomal enzyme activity was determined in 4 week old premature and 12 week old adult rats. Aminopyrine-N demethylation was not different, but p-nitrophenol hydroxylation and p-nitroanisole O-demethylation were significantly higher in premature rats compared to adult indicating that the P450 2E 1 activity decreases with the maturity of rats. However, no difference in the triglyceride accumulation induced by an intraperitoneal dose of ethanol (3 g/kg) was noted between premature and adult rats. The results suggest that the P450 2E1 activity dose not play an important role in the induction of acute alcoholic fatty liver.

Effects of the extrusion temperature and die angle on the tensile properties of SiCIyAl composites in powder extrusion have been investigated. SiCP/Al composites were extruded at various extrusion temperatures (450, 500, ) under the extrusion ratio of 25 : 1. The ram speed was maintained at 13 cm/min for all the extrusion conditions. The surface of the extruded rod appeared to be smooth without tearing at 450 and 50, whereas it was very rough due to tearing at . It was found that the tensile strength and elongation of the composites extruded at are greater than those of composites extruded at This is due to the easier plastic deformation of composite extruded at , compared with the composites extruded at . The effect of die angle was examined under 20=60, 120, die angles at extrusion temperature of under 25:1 extrusion ratio. The tensile strength of the composites extruded with 20=approved to be higher than that of the composties extruded with 28 : 120 and This is attributable to the higher extrusion pressure, which mixed composite powders could be densely consolidated at elevated temperatures, resulting from high friction force between billet and sliding surface of conical die.

The 4.8GHz formaldehyde absorption line in the dark clouds in M17 and NGC 2024 regions has been mapped. In both nebulae, we detected two H2CO line components. In M17, the 24km S-1 cloud is closely associated with the HII region located in front of the radio continuum source, and the 19km S-1 cloud is associated with the visual dark clouds with a larger extent which are closer to us. The 19km S-1 cloud has a mass motion approaching to the HII region. In both clouds, a velocity gradient from the north-east to the south-west directions is observed. The linewidth has no variation indicating no collapsing motion. In NGC 2024, the 9km S-1 feature is extended along the dark bar in front of the bright nebula and a weak second component at 13km S-1 is confined to the immediate vicinity of the radio source. Indications are that the 9km S-1 cloud is physically associated with the dark bar and the 13km S-1 cloud is located behind the radio source. The angular extent, the column density, and the total mass of the clouds are derived. The radial velocities of other molecular lines observed in these clouds are compared.

실험선 제주 402호의 조종성능을 전속전진중 최대타각으로 전타한 때의 선회권측정과 10˚, 20˚, 30˚Z시험에서 산출된 조종성지수를 분석, 검토한 결과를 요약하면 다음과 같다. 1. 선회종거는 우현선회시가 79.1m로 배의 길이의 약 2.6배였으며, 좌현선회시는 81.4m로서 배의 길이의 약 2.7배였다. 또, 선회경은 배의 길이의 약 2.6배로서 우현선회시가 78.3m로서 좌현선회시 80.4m보다 작았다. 2. 선회권시험시 속력저감율은 0.49였으며, 평균선회각속도는 우현선회시가 4.3˚/sec, 좌현선회시는 4˚/sec이었다. 3. Z시험 결과 over shot angle은 우현전타시가 좌현전타시보다 더 컸으며, 좌우타전타시의 평균값은 10˚Z시험시가 10.5˚, 20˚Z시험시가 20.5˚, 30˚Z시험시가 29.5˚로 다소 큰 편이었다. 4. 10˚, 20˚, 30˚Z시험에서 K' 및 T'의 값은 각각 0.755, 0.566, 0.481 및 3.468, 1.621, 1.547로서 대체적으로 선회성은 대각도 전타 일수록 나쁘거나, 추종성은 대각도 전타 일 수 록 좋았다.