• Journal of Dairy Science and Biotechnology
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• v.26 no.1
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• pp.1-4
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• 2008

Melatonin is one of the functional hormones in the milk and found in all mammalian species. The primary motivation for the use of melatonin as a supplement is as a natural aid to better sleep. Melatonin contents in milk vary according to the naturally occurring factors such as seasons and milking times. As a number of studies indicate melatonin supplementation helps to reduce the age-related decline in hormone production and overall enhancement of health, the more detailed studies are required to know the nature of milk derived hormones and to clarify them as a functional value adaptation. The objectives of this study were to examine the change of melatonin content in bovine milk during different milking times at the two dairy farms and during dairy process including homogenization and pasteurization. Commercial dairy products including night time milking products(night milk) marketed in Japan were also investigated. Melatonin content was determined by radioimmunoassay using 125I. Individual milk was collected from lactating Holstein cows at Kyong-Ki province in Korea. At farm A, the melatonin contents milking at 4 a.m. was higher than those of 7 p.m. and 12 p.m.($6.90{\pm}3.55,\;2.01{\pm}1.47$ and $0.16{\pm}0.04pg/mL$, respectively). At farm B, the mean melatonin contents milked from 24:00 AM to 05:00 AM have shown the highest contents ($4.65{\pm}$0.72pg/mL), and milking samples of the rest time had very little or non-detection of melatonin contents. Melatonin contents of commercial night milk samples were about 5 times higher than those of other common milk products. These results suggested that melatonin might be heat-resistant and commercial dairy process might not affect its contents in the final products.

• Journal of the Korean Electrochemical Society
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• v.17 no.1
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• pp.7-12
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• 2014

There is increasing demand on the reducing the weight and the volume of the major components in lithium secondary battery to improve energy density. Separator not only provides pathway for lithium ion movement but also prevents direct contact between anode and cathode. Herein we fabricated polyethylene separator by varying biaxial stretching ratio to obtain membrane thickness of 16, 12, and $9{\mu}m$. Mechanical and thermal properties of the separator with different thickness were investigated. Also rate capability and charge-discharge cycle property up to 500 cycles were studied using coin type full-cell with $LiCoO_2$ and graphite as a cathode and an anode, respectively. All the cells using separator with different thickness demonstrated excellent capacity retention after 500cycles (around 80%). Considering the rate capability, cell using separator with thickness of $9{\mu}m$ showed best performance. Interestingly, separator thickness of $9{\mu}m$ was more resistant to heat contraction compared to that of $16{\mu}m$ separator.

• Korean Journal of Food Science and Technology
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• v.47 no.1
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• pp.63-69
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• 2015

The aim of this study was to investigate the deformation of packaging materials used for ready-to-eat (RTE) foods after the retort process and microwave heating. From the multilayer films consisting of polyethylene terephthalate (PET), polyamide (PA), and cast polypropylene (CPP) in a stand-up pouch form used for RTE foods, some deformation of the CPP layer, which was in direct contact with the food, was observed after the retort process and microwave heating. The damage was more severely caused by microwave heating than by the retort process. This may be attributed to diverse factors including the non-uniform heating in a microwave oven, the sorption of oil into the packaging film, and the different characteristics of food components such as viscosity, salt and water content. The development of heat-resistant packaging materials and systems suitable for microwave heating of RTE foods is required for the safety of consumers.

• The Korean Journal of Physiology and Pharmacology
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• v.2 no.6
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• pp.733-742
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• 1998

Background: We have previously reported that not only cGMP but also 8-Br-cGMP or 8-pCPT-cGMP, specific and potent stimulators of cGMP-dependent protein kinase (cGMP-PK), increased basal L-type calcium current $(I_{Ca})$ in rabbit ventricular myocytes. Our findings in rabbit ventricular myocytes were entirely different from the earlier findings in different species, suggesting that the activation of cGMP-PK is involved in the facilitation of $I_{Ca}}$ by cGMP. However, there is no direct evidence that cGMP-PK can stimulate $I_{Ca}}$ in rabbit ventricular myocytes. In this report, we focused on the direct effect of cGMP-PK on $I_{Ca}}$ in rabbit ventricular myocytes. Methods and Results: We isolated single ventricular myocytes of rabbit hearts by using enzymatic dissociation. Regulation of $I_{Ca}}$ by cGMP-PK was investigated in rabbit ventricular myocytes using whole-cell voltage clamp method. $I_{Ca}}$ was elicited by a depolarizing pulse to +10 mV from a holding potential of -40 mV. Extracellular 8-(4-Chlorophenylthio)-guanosine-3',5'-cyclic monophosphate (8-pCPT-cGMP), potent stimulator of cGMP-dependent protein kinase (cGMP-PK), increased basal $I_{Ca}}$. cGMP-PK also increased basal $I_{Ca}}$. The stimulation of basal $I_{Ca}}$ by cGMP-PK required both 8-Br-cGMP in low concentration and intracellular ATP to be present. The stimulation of basal $I_{Ca}}$ by cGMP-PK was blocked by heat inactivation of the cGMP-PK and by bath application of 8-(4-chlorophenylthio)-guanosine-3',5'-cyclic monophosphate, Rp-isomer (Rp-pCPT-cGMP), a phosphodiesterase-resistant cGMP-PK inhibitor. When $I_{Ca}}$ was increased by internal application of cGMP-PK, IBMX resulted in an additional stimulation of $I_{Ca}}$. In the presence of cGMP-PK, already increased $I_{Ca}}$ was potentiated by bath application of isoprenaline or forskolin or intracellular application of cAMP. Conclusions: We present evidence that cGMP-PK stimulated basal $I_{Ca}}$ by a direct phosphorylation of L-type calcium channel or associated regulatory protein in rabbit ventricular myocytes.

• Korean journal of applied entomology
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• v.16 no.4 s.33
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• pp.229-234
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• 1977

The experiments were carried out to investigate the selection effects on the drug resistance to Agrepto in Xanthomonas oryzae, the causal bacteria of rice bacterial leaf blight. The results obtained were as follows. 1, The Agrepto was stable at the heat treatment of $105^{\circ}C$ for 20 minutes, when the drug was added in the media. 2. The local isolates of the bacteria, 75-6 and 75-9, showed the different resistante reaction, when they were selected by the Agrepto contained media which concentrations of 10r9/m1 and 100ug/ml. 3. The individuals shelving high degree of resistance, which can grow on the media contained 10,000ug/m1 of Agrepto, could selected by the concentrations as low as 10ug/ml and 100ug/m1, in one generation. 4. The highly resistant isolates which selected by 3-stepwise selections such as 100ug/ml, 3,000ug/ml and 10,000/ml plots, showed nearly normal growth at the media contained 100ug/ml of Agrepto 5. When the isolate 75-9 was selected at the 100ug/m1 of concentration, showed various degrees of resistance, indicating that the isolate may be composed of resistance groups that lower than 500ug/ml, between 500-1,000ug/ml and 1,000-3,000ug/ml, to the Agrept.

• The Korean Journal of Mycology
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• v.30 no.2
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• pp.119-123
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• 2002

In the previous studies, we surveyed 68 Korean wild mushrooms for their hemolytic activity and found that cold-water extract of Hebeloma crustuliniforme contained heat-resistant hemolysin. In this study, partially purified hemolysin of the mushroom was obtained by cold-water extraction followed by precipitation with ammonium sulfate, solubility fractionation and then dialysis. The hemolysin was found to be > 12,000 in molecular weight and its optimal hemolytic temperature was $37^{\circ}C$ and it's hemolytic activity, on washed erythrocytes and unwashed erythrocytes, respectively, was in the order of sheep > rat > human ${\geq}$ mouse > chicken and sheep > mouse > human ${\geq}$ rat > chicken. When ip injected into ICR mice at 1.38 mg/kg, it incurred prompt hemolysis as well as severe renal toxicity and hepatotoxicity. These results strongly suggest that the toxicity of Hebeloma crustuliniforme, which had been well-known as a toxic wild mushroom, may be at least partly due to its hemolysin.

• Microbiology and Biotechnology Letters
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• v.6 no.1
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• pp.41-46
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• 1978

Piscicidal substance produced by Streptomyces sp. isolated from soil was toxic against various kinds of fish. After extraction with CH$Cl_3$ from the culture medium, the substance was purified by avicel column chromatography. In order to test toxicity, various kinds of fish were subjected to the acqueous solution of 100 us of the substance per liter of water. Generally, the substance was toxic to most fish, but Macropodus chinenes and Misgurnus mizolepis are resistant to the substance than Gobius similis and Pseudorasbora parva. The substance was stable at pH range, 3.0 to 7.0, but labile at alkaline pH, and to heat as well. Succinic dehydrogenase on most of tissue cell of Cyprinus carpio was inhibited by this substance strongly, but spinal cord was not inhibited. By addition of Cu and Pb salts to the culture medium, piscicidal substance producibility was activated.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.27 no.6
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• pp.675-681
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• 1994

[ $F_0$ ]-values of the canned tuna in cottonseed oil (CTCO) were investigated under different sterilizing conditions to optimize the energy consumption and microbiological safety. The $F_0$-values were measured using a microcomputer based technique. The exact cold point was not the volumetric center of the cans, and it was located in the center of meat mass in can which had ca. $6\%$ of head space. Location of the test cans in retort showed no remarkable influence on the $F_0$-values when the cans were jumble loaded. The process time before sterilization should be shortened as much as possible to prevent the contamination of microorganisms. Thermophilic spore forming bacteria found from raw and precooked tuna were Bacillus subtilis, Bacillus cereus and Bacillus pasteurii, and the most heat resistant was Bacillus subtilis. The rational $F_0$-value for the CTCO obtained from the preservation test was regarded as 6min.

• KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
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• v.21 no.3
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• pp.97-106
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• 2015

Thermal deformation of packaging materials was observed in some ready-to-eat food products for microwave use. Therefore, the deformation patterns depending on packaging types and shapes of 9 domestic and 11 foreign products after microwave heating were investigated. Among the domestic and foreign products, thermal deformations of packaging material were observed in 5 and 8 samples, respectively. Besides, thermal deformation occurred on the lid and cup body of tray filled with a spicy chicken sauce after having microwaved where previously no deformation had been observed with other food types. No consistent results of thermal deformation were obtained by the analysis of salinity, brix, pH and viscosity of RTE products for microwave heating. However, thermal deformations of packages were less found in the packages used for the RTE foods contained very high or low viscosity than those with medium viscosity. Furthermore, the degree of thermal deformations was dependent on the food composition and shape as well as package type. In order to prevent the thermal deformation of packaging materials, therefore, technological advances and further studies are required to develop the heat-resistant packaging system and to improve the non-uniformity during microwave heating of RTE foods.

• Korean Journal of Food Science and Technology
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• v.31 no.1
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• pp.183-188
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• 1999

The incidence of Yersinia enterocolitica in raw meat was determined over 10 month period. Y. enterocolitica was isolated from 8.5% of beef, 17.0% of pork and 25.6% of chicken. Overall prevalence of Y. enterocolitica in raw meat was 17.5%. Seasonal difference was observed in isolation rate in which pork and chicken samples collected in the second half of the year twice was more than that of the first half of the year. Serotypes of Y. enterocolitica isolates were O:5 (17.3%), O:8 (8.6%), O:3 (6.2%), O:1,2 (1.2%), and others. The antibiotics susceptibility tests showed Y. enterocolitica isolates were resistant to carbenicillin, ampicillin, erythromycin, penicillin and bacitracin. In contrast it showed sensitivity to polymyxin B, kanamycin, ciprofloxacin, gentamicin, trimethoprim/sulfamethoxazole, nalidixic acid, and tetracycline. PCR with specific primers derived from ail gene of Y. enterocolitica was applied to detect and confirm pathogenic Y. enterocolitica. About 10% of the isolated Y. enterocolitica proved to be pathogenic and most of them were found in pork. However, proper cooking and meat process can kill and remove all Y. enterocolitica in meat, because the organism is very sensitive to heat.