• Journal of The Korean Society of Grassland and Forage Science
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• v.36 no.1
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• pp.23-28
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• 2016

The present study was carried out to explore the potential effects of novel lactic acid bacteria Pediococcus penticeous KCC-23 (KCC-23) and Lactobacillus plantarum KCC-24 (KCC-24) on rye haylage fermentation at National Institute of Animal Science, Cheonan province in Korea. The experiment contains three different groups such as control without lactic acid bacteria, rye haylage with KCC-23 and rye haylage KCC-24. After experimental periods, the content of crude protein, acid detergent fiber (ADF), neutral detergent fiber (NDF), the activity of total digestible nutrient (TDN) and In-vitro digestibility (IVD) was similar in control and LAB treated haylage (p<0.05). The pH was reduced in KCC-23 and KCC-24 treated rye haylage as compared to control (p<0.05). The lactic acid concentration in haylages was increased by L. plantarum KCC-23, and KCC-24 supplement. Whereas, the less amount of acetic acid and butyric acid was noted in KCC-23 and KCC-24 treated haylage as compared with control (p<0.05). The KCC-23 and KCC-24 were dominantly grown in experimental haylage as compared with control. It indicates, the addition of KCC-23, and KCC-24 enhances fermentation quality of haylages as compared control. The present study suggests that KCC-23 and KCC-24 are potent strains that were improving the fermentation process in rye haylage

• Journal of the Korean Society of Food Science and Nutrition
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• v.32 no.7
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• pp.976-980
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• 2003

A strain of potential producer of fibrinolytic enzyme was isolated from Korean fermented food. The isolated bacterium was identified and named as Bacillus brevis KJ-23. The optimal condition of the medium for the production of fibrinolytic enzyme from Bacillus brevis KJ-23 was nutrient broth with 0.5% D-ribose, 0.5% malt extract and 0.3% $K_2$HPO$_4$. The optimum pH, temperature and fermentation time for the enzyme production were pH 7.0, 3$0^{\circ}C$ and 24 hr, respectively.

• Sleep Medicine and Psychophysiology
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• v.15 no.2
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• pp.87-93
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• 2008

Introduction: Although it is well known that medical students are not getting an adequate amount of sleep, there have been only few studies on the sleep patterns of medical students in Korea. Therefore, the present study aimed to investigate the life style and sleep patterns of Korean medical students and the impact they have on the students' academic performance. Methods: A questionnaire package was administered to the $3^{rd}$ year medical students at the Seoul National University to examine their sleep patterns on weekdays and weekends. It consisted of questions asking about their lifestyles as well as Pittsburgh sleep quality index (PSQI) and GPA (Grade Point Average) that are considered relevant to their sleep patterns. A total of 110 students (85 males and 25 females, mean age $24.4{\pm}20.6$) responded to the survey and the result was analyzed using the independent t-test, the chi-square test, the paired t-test, Pearson's rank correlation and ANOVA. P-values of less than 0.05 were considered statistically significant in all analyses. Results: The weekend bedtime was significantly delayed (01：24 on weekday；03：12 on weekend; t=-5.23, p<0.01), the weekend rise time was delayed (07：36 on weekday；10：30 on weekend ; t=-24.48, p<0.01) and the total sleep time was increased on weekends (5：57 on weekday；8：17 on weekend ; t=15.94, p<0.01). They wished to sleep for 7 hours 6 minutes which was different from their actual weekday total sleep time (t=-11.41, p<0.01). The poor sleeper group had lower GPAs than the good sleeper group (t=2.05, p<0.05). The GPA of medical students were negatively correlated with age (r=-0.23, p<0.05), daily amount of smoking (r=-0.78, p<0.01), total amount of smoking (r=-0.75, p<0.01), weekday sleep latency (r=-0.23, p<0.05), weekend sleep latency (r=-0.23, p<0.05) and PSQI score (r=-0.30, p<0.01). Conclusion: Medical students were experiencing a lack of sleep during weekdays as they have a later bedtime and earlier rise time, and consequently had more hours of sleep on weekends. Overall, the responded students were experiencing poor sleep quality, and the GPAs of the poor sleeper group were lower than those of the good sleeper group.

• Journal of Food Hygiene and Safety
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• v.37 no.2
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• pp.80-86
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• 2022

The purpose of this study was to examine the microbiological and physicochemical changes on packaged tofu stored at temperatures of 5, 13, 23, and 30℃, and measure the consumable period from the expiry date to ultimately evaluate the microbiological safety on the extension of the consumable period. From the investigation, the pH value of tofu at each storage temperature (5, 13, and 23℃) showed a slight decrease over the storage period, although there was no significant change. The hardness of packaged tofu decreased more rapidly as temperature and storage time increased and the tofu started to show signs of decomposition at the same time. Analysis on the microbial change of tofu at different storage temperature revealed that the number of general bacteria also increased as the temperature increased. It was further found that packaged tofu takes 25 days at 5℃, 7 days at 13℃, and 1 day at 23℃ from the expiry date until the general bacteria count is at least at the early decomposition level which is 10℃ log CFU/g. However, no coliform bacteria was detected from tofu after storing at 5, 13 and 23℃. When packaged tofu was stored at 5℃, the L value changed significantly after 26 days, whereas the a and b values showed no significant change during the storage period (P>0.05). When storing tofu at 13℃ and 23℃ the L value decreased after 8 and 3 days, respectively. However, both a and b values increased (P<0.05).

• Journal of Dental Rehabilitation and Applied Science
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• v.32 no.1
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• pp.16-23
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• 2016

Purpose: The aim of this study was to evaluate whether fluorides at various pH cause changes in the surface roughness of titanium implants that alter the adherence of bacterial biofilms. Materials and Methods: The titanium disks were assigned randomly to the following seven groups according to the fluoride agents and application time (1 minute or 30 minute) used: control (no treatment); group 1 (1.23% acidulated phosphate fluoride [APF] at pH 3.5 for 1 minute); group 2 (1.23% APF at pH 3.5 for 30 minute); group 3 (1.23% APF at pH 4.0 for 1 minute); group 4 (1.23% APF at pH 4.0 for 30 minute); group 5 (2% NaF gel at pH 7.0 for 1 minute); group 6 (2% NaF gel at pH 7.0 for 30 minute). The surface roughness of the titanium disks and the amount of adherent bacteria were measured. Results: Group 2 showed a significantly greater surface roughness than the control group (P < 0.0001). No significant differences in the amount of surface bacteria were observed between the treated samples and the controls. In addition, there were no significant differences in bacterial adherence relative to the incubation period between the treated samples and the controls. Conclusion: The surface roughness of the titanium disks was significantly greater after treatment with APF at pH 3.5 for 30 min compared with that of the controls. In addition, we found that the amount of Porphyromonas gingivalis, Fusobacterium nucleatum, and Aggregatibactor actinomycetemcomitans was similar among all groups

• Journal of Physiology & Pathology in Korean Medicine
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• v.19 no.3
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• pp.628-632
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• 2005

The aim of this study was to investigate the cytotoxic effect and its mechanism on Radix Aconiti(RA) extract in lung cancer cell lines. RA extract treatment decreased the cell viability in a dose-dependent fashions in lung cancer cells including A549, H460, H23 and H157 cells. Many investigators reported that A549 and H460 cells expressed wild-type p53, but H23 and H157 cells preserved mutated p53. After treatment with RA extract in A549 and H460 cells, we measured the expression of p53 protein levels using Western blot. analysis. In both cells treated with RA extracts, p53 protein expressions were increased in a dose-dependent manner. In our experiments, RA extracts also have cytotoxic effects in H23 and H157, which have mutated p53. Treatment with RA extract decreased bcl-2 protein expressions in both cells. These results suggest that RA extracts have cytotoxic effects via p53 expression increase and bcl-2 inhibitable pathways in A549, H460 cells and H23, H157 cells, respectively.

• The Journal of Traditional Korean Medicine
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• v.15 no.1
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• pp.106-112
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• 2006

The aim of this study was to investigate the cytotoxic effect and its mechanism on Radix Aconiti(RA) extract in lung cancer cell lines. RA extract treatment decreased the cell viability in a dose-dependent fashions in lung cancer cells including A549, H460, H23 and H157 cells. Many investigators reported that A549 and H460 cells expressed wild-type p53, but H23 and H157 cells preserved mutated p53. After treatment with RA extract in A549 and H460 cells, we measured the expression of p53 protein levels using Western blot. analysis. In both cells treated with RA extracts, p53 protein expressions were increased in a dose-dependent manner. In our experiments, RA extracts also have cytotoxic effects in H23 and H157, which have mutated p53. Treatment with RA extract decreased bcl-2 protein expressions in both cells. These results suggest that RA extracts have cytotoxic effects via p53 expression increase and bcl-2 inhibitable pathways in A549, H460 cells and H23, H157 cells, respectively.

• Food Science of Animal Resources
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• v.32 no.5
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• pp.678-684
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• 2012

The melanin pigment in human skin is a major defense mechanism against ultraviolet light to the skin, but darken skin color. Tyrosinase is mainly responsible for melanin biosynthesis (melanogenesis) in animals and enzymatic browning (melanosis) in plants. The purpose of this study was to optimize the fermented milk process for the melanin formation inhibition by using Lactobacillus plantarum M23 with tyrosinase inhibitory activity. We used 4-factor-3-level central composite design combining with response surface methodology. Yeast extract concentration (%, $X_1$), addition of grape (%, $X_2$), incubation temperature ($^{\circ}C$, $X_3$) and incubation time (h, $X_4$) was used as an independent factor, on the other hand, pH (pH, $Y_1$), overall palatability (score, $Y_2$) and tyrosinase inhibitory activity (%, $Y_3$) was used as a dependant factor. Based on the optimization for the highest tyrosinase inhibitory activity with pH 4.4, the expected data of pH, palatability and tyrosinase inhibitory activity with 14.8 h incubation at $37.1^{\circ}C$ by the addition of 0.127% of yeast extract, 2.95% of grape was 4.42, 7.06 and 86.65%, but the real data was 4.35, 6.86 and 84.05%, respectively. Based on the previous results, fermented milk using Lactobacillus plantarum M23 with the tyrosinase inhibitory activity could contribute for the whitening and antiaging of human skin.

• Communications of the Korean Mathematical Society
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• v.23 no.4
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• pp.479-485
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• 2008

In this note, we study arithmetic properties for the exponents of modular forms on ${\Gamma}_0(p)$ for primes p. Our aim is to refine the result of [4] by using the geometric property of the modular curve of ${\Gamma}_0(p)$.

• The Pure and Applied Mathematics
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• v.23 no.2
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• pp.131-143
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• 2016

In this paper, we present some common fixed point theorems for two pairs of weakly compatible self-mappings on multiplicative metric spaces satisfying a generalized Meir-Keeler type contractive condition. The results obtained in this paper extend, improve and generalize some well known comparable results in literature.