• Journal of the Korean Crystal Growth and Crystal Technology
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• v.19 no.1
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• pp.6-10
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• 2009

In this paper, a selective area growth (SAG) of a GaN/AlGaN double heterostructure (DH) has been performed on r-plane sapphire substrate by using the mixed-source hydride vapor phase epitaxy (HVPE) with multi-sliding boat system. The SAG-GaN/AlGaN DH consists of GaN buffer layer, Te-doped AlGaN n-cladding layer, GaN active layer, Mg-doped AlGaN p-cladding layer, and Mg-doped GaN p-capping layer. The electroluminescence (EL) characteristics show an emission peak of wavelength, 439 nm with a full width at half maximum (FWHM) of approximately 0.64 eV at 20 mA. The I-V measurements show that the turn-on voltage of the SAG-GaN/AlGaN DH is 3.4 V at room temperature. We found that the mixed-source HVPE method with a multi-sliding boat system was one of promising growth methods for III-Nitride LEDs.

• Korean Journal of Health Education and Promotion
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• v.20 no.3
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• pp.189-205
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• 2003

The purpose： This study was to get database of health service for smoking prevention through investigating the state of the students' experience, knowledge and attitude on smoking. Method： The subjects were cosisted of 545 students who were currently enrolled in 3, 4, 5 and 6th grade of 4 primary school in J community. The instruments for this study were Smoking Knowledge and Smoking Attitude questionaire (40 items) developed by WHO(l982). Frequency, percentage, t-test, ANOY A and Chi- square test with SAS program were used to analyze the data. Result： Among the students 10.8％ answered they had the experience of smoking, while 0.5％ said they are current smokers. The experience of smoking related to general characteristics were showed significantly different according to sex, grade and received or not received of smoking exhort. With regard to smokers smoking behavior, first beginning time of smoking was most by 29.8％ preschooler and the first motive of smoking was most by 80.8％ curiosity. The main smoking area is most by 31.1 ％ own house or friend's house. The main purchase route of tobacco appeared by thing which house(father or brother's tobacco) most by 34.9％. Smoking period was most less than 1 day and smoking frequency was most stops while bum sometimes. The amount for a day was less than one cigarette. Smoking time was appeared highest when curiosity occurs. Students' knowledge level about smoking prevention is high comparatively to mean 15.44(±2.66). Smoking prevention knowledge level related to general characteristics were showed significantly different according to the grade, academic score and learned or not of smoking prevention. Therefore, was expose that the smoking prevention knowledge level is high in students who results high grade, high academic score level and learned of smoking prevention. Students' attitude level about smoking prevention was high level to mean 55.90(±3.58). Smoking prevention attitude level related to general characteristics were showed significantly different according to academy score and received or not of smoking exhort(t＝2.33, p＝.020). Therefore, was expose that the smoking prevention attitude level is high in students who result high academic score level and received of smoking exhort group. Conclusion： It follows from this study that education for smoking prevention should be continued from lower grade students and teaching for refusal skill against smoking is needed.

• Korean Journal of Poultry Science
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• v.33 no.4
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• pp.273-281
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• 2006

Singeing has always been equated with meat color alteration through lipid oxidation and microbial population. Singeing method has always been employed far removing duck feathers, however, the effect of singeing on storage characteristic of duck meat has not been investigated extensively. The study was therefore, designed to Investigate the effect of singeing on duck meat during storage extensively. For the purpose, study was categorized into three groups namely A, B, and C, representing 0, 50 and 70 seconds of singeing time. Singeing was performed on 100 birds in each group, however, only 20 singed birds from each treatment groups were further selected to analyse them subsequently during storage. Analysis revealed that with 70 seconds singeing time drip loss was significantly (p<0.05) higher at $6mgf/cm^2$ compared to 50 seconds of singeing. With 70 seconds treatment breast meat apparently appeared black, where as with 50 seconds treatment no change was observed. Breast showed low redness with more duration of treatment compared to less treatment duration. Yellowness increased, springiness declined and no change was observed in cohesiveness and chewiness with high treatment time. There was increase in the TBARS and VBN, freshness did not change for first 5 days, however, K values started to increase later on indicated decline in freshness. Conclusively, it was inferred from the study that 50 seconds singeing does not make much alternation in the quantitative traits and at the same time maintains the microbial level under permissible limit.

• Food Science of Animal Resources
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• v.24 no.1
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• pp.97-102
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• 2004

The objective of this study was to control Kimchi fermentation using pH sensitive bacteriocin entrapping liposome(bacteriocin-liposome). The liposomes were prepared by the reverse-phase evaporation method from a mixture of DPPC(dipalmitoyl phosphatidylcholine, DPPE(dipalmitoyl phosphatidylethanolamine), DOPC(dioleoyl phosphatidylcholine) and cholesterol in a molar ration of 4:2:1:4. The bacteriocin-liposome was disruptured at pH 4 of buffer and was stable at alkaline pHs(6 and 7). Irrespective of the addition of the bacteriocin-liposomes, the pH of every Kimchi sample decreased to 5 during 5 days storage at 5$^{\circ}C$. Kimchi samples treated with bacteriocin-liposomes maintained pH 4 or higher, while Kimchi samples not treated with bacteriocin-liposomes exhibited pH 3.58 or lower. In general, the pH of Kimchi samples stored at 20$^{\circ}C$ decreased faster, compared to that of Kimchi samples stored at 5$^{\circ}C$. The pH of Kimchi samples treated with the bacteriocin-liposomes was 3.9 during 90 days storage, while that of the samples not treated with the bacteriocin-liposomes was 3.68 and 3.32 during 30 days and 90 days storages, respectively. Lactic acid bacteria in Kimchi treated with the bacteriocin-liposome grew relatively slow at 5$^{\circ}C$. The viable cell number of lactic acid bacteria increased up to 4${\times}$10$\^$7/ cells/ml and then decreased to 8${\times}$10$\^$6/ cells/ml during 90 days storage at 5$^{\circ}C$.

• Proceedings of the Korean Society of Embryo Transfer Conference
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• 2002.11a
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• pp.113-113
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• 2002

The stimulatory effect of EGF and FSH on oocyte maturation have been reported in various mammalian species. And some reports presented FSH enhanced the effect of EGF on oocyte maturation. But, the interaction between EGF and FSH on nuclear maturation of mammalian oocytes is not fully understood. We observed the effect of EGF and FSH on nuclear maturation during in vitro maturation of mouse oocytes. Also, we examined the interaction between EGF and FSH on nuclear maturation of mouse oocytes using the EGFR inhibitor or FSH inhibitor. Germinal vesicle (GV) stage oocytes were obtained from 3-4weeks PMSG primed BCFI hybrid mice and cultured in TCM-199 medium with 0.4%PVP supplemented with/without EGF (1ng/ml), FSH (1ug/ml), EGFR specific tyrosine kinase inhibitors: Tyrphostin AG 1478 (500nM), MAP kinase kinase inhibitor : U0126 (20uM) or PD 98059 (100uM) for 14-l5hr. Rapid staining method were used for the assessment of nuclear maturation. Nuclear maturation rates of EGF indjor FSH-treated group were significantly higher than those of control group. Treatment of EGFR inhibitor significantly block the nuclear maturation of GV oocyte in EGF-treated group, but it did not block those of GV oocyte in FSH-treated or FSH and EGF-treated group. Treatment of FSH inhibitor(U0126, PD98059) significantly block the nuclear maturation of EGF-treated group, FSH-treated and FSH and EGF-treated group. These results show that EGF has a stimulatory effect as well as different action pathway with FSH on in-vitro maturation of mouse oocyte in vitro. Therefore, further studies will be needed to find the signaling pathway of EGF associated with nuclear maturation.

• Journal of Physiology & Pathology in Korean Medicine
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• v.20 no.2
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• pp.365-371
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• 2006

Bee Venom aqua-acupuncture (BVA) simultaneously exerts pharmacological effects of biologically active compounds, existed in the whole bee venom, and medicinal effect of the stimulation of acupuncture points. BVA has been considered as a promising therapeutic method for treating various chronic diseases, mainly accompanying severe pain and inflammation. As a painless injection device, jet injectors have been commercially marketed for various clinical applications including insulin injection and vaccination. Among them, a pressure-driven jet injector system could be used for intradermal delivery of a variety of drugs. The aim of this study was to investigate the analgesic effects of the BVA using a needle-free injector (Biojector $2000^{\circledR}$, Bioject Inc., OR, USA), compared to the conventional BV aqua-acupuncture using a typical syringe. Adult Sprague-Dawley rats were injected with bee venom $(0.08mg/kg,\;50{\mu}l)$ using Biojector $2000^{\circledR}$ (BVA-B) or a syringe (BVA-5) into the Zusanli (ST36) acupoint, 30 minutes before plantar injection of 2% formalin. It was found that BVA-B-, or BVA-5-treated rats, compared to controls, exhibited significantly less licking behavior during the late phase in the rat formalin test, when compared to controls. During early phase, however, those effects were not significant but substantial. The analgesic effect of BVA-B was also compatible with that of the conventional BVA-5. In the immunohistochemical studies, BVA-B significantly suppressed the expression of formalin-evoked c-fos, a biomarker of neuronal activity, in the lumbar dorsal horn of the spinal cord. These results indicated that BVA-B waseffective in the modulation of pain in the rat formalin test, compared to BVA-5. Taken together, the needle-free jet injector system could be substituted for the conventional aqua- acupuncture with the advantage of little pain.

• Asian-Australasian Journal of Animal Sciences
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• v.14 no.9
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• pp.1233-1237
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• 2001

A study was conducted to determine the effects of maturity at harvest and wilting days on the quality of round baled rye (Secale cereale L.) silage. This study was a $3{\times}3$ factorial arrangement in a split plot design with 3 replicates. The main plot was 3 harvesting dates at the stage of boot (20 Apr.), heading (29 Apr.) and flowering (14 May). The subplot was wilting day : 0 (unwilted), 0.5 and 1 day (0, 1, and 2 days at boot stage). Acid detergent fiber (ADF) and neutral detergent fiber (NDF) contents of rye silage were significantly greater than those of rye before ensiling, but crude protein (CP) content and in vitro dry matter digestibility (IVDMD) were vice versa. Buffering capacity (BC) of rye harvested at flowering stage was decreased from 264 to 202 meq/kg at 1 day wilting, however, it was increased when harvested at boot or heading stage. The pH in wilted silage was the highest while that of flowering stage was the lowest. Water soluble carbohydrate (WSC) content of wilting rye was lower than that of unwilted, and the lowest at late harvesting stage. All plots had minimal WSC content for silage fermentation. Wilting treatment and delayed harvesting date caused an increase in dry matter (DM) content of round bale silage. The content of ammonia-N expressed as a portion of total N showed negative correlation with DM content. High quality silage according to ammonia-N content could be obtained from mid-harvest with wilting. There were highly significant differences in each organic acid between harvesting dates and wilting periods. Acetic and butyric acid contents were increased with delayed harvesting and prolonged wilting period, the lactic acid content, however, was decreased. This study demonstrated that harvest of rye from heading to flowering stage with wilting would be a recommendable method for making high quality rye silage using round bale system.

• KSBB Journal
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• v.21 no.4
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• pp.306-311
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• 2006

Cell preservation is indispensable in animal cell culture process and should be established according to the cell characteristics. In this study, we experimented hypothermic preservation of CHO cells that is widely used in pharmaceutical industry to produce therapeutic proteins and established a stable method of preservation. The highest viability of CHO cells was obtained when the cells were preserved using rolling tube, which means the cells should be suspended to avoid the cell lumping during the preservation. Also, we obtained superior preservation result under the anaerobic condition. To evaluate the serum-free media as a preservation solution, we investigated cell growth after hypothermic preservation using serum-free media. High cell viability and normal cell growth was observed during 10 days using serum-free media. Moreover, we found that more effective preservation when ${\alpha}$-tocopherol and retinoic acid is added to media as an additive. In the case of 1 liter large scale hypothermic preservation using established protocol, cell viability and growth rate was obtained as good as small scale one. This study is considered to be helpful for hypothermic preservation of CHO cells and large scale hypothermic preservation may be available through the further studies.

• Journal of Life Science
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• v.22 no.8
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• pp.1092-1098
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• 2012

This study was carried out to discover the skin wrinkle reducing components in the seeds of Arctium lappa. The isolation of a methylene chloride-soluble fraction of 70% ethanol extract from the seeds of Arctium lappa using a procollagen type-1 synthesis and MMP-1 activity resulted in the isolation and identification of four lignin compounds: arctiin, arctigenin, matairesinol, and diarctigenin. All structures were confirmed via NMR and MS spectroscopic data. To determine cell viability and procollagen type-1 synthesis, human dermal fibroblasts were treated with 10-100 ${\mu}M$. As a result, none of the four compounds showed cytotoxicity up to 50 ${\mu}M$. We also investigated their procollagen type-1 synthesis and MMP-1 inhibition activity and found that arctiin had the highest activity in terms of both procollagen synthesis and MMP-1 inhibition among all four compounds. Putting all the data together, we suggest that arctiin be used in cosmetics as an anti-wrinkle material.

• Journal of the Mineralogical Society of Korea
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• v.20 no.1 s.51
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• pp.1-6
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• 2007

Hectorite was synthesized by a two-step hydrothermal process from $Mg(OH)_{2}$, water glass (${\sim}30\;wt%\;SiO_{2}$) and Li-compound at $90{\pm}5^{\circ}C$. The product shows excellent dispersion and swelling properties. The mixture of the starting materials was heated in a glass vessel for the first reaction with continuous stirring and the pH of the solution was adjusted to $6{\sim}8$, resulting in the formation of a precursor of hectorite. The excess salt components were washed out from the resulting slurry and then was matured in the glass vessel for the 2nd reaction. Li compound was added during the reaction. After a 10 h retention, the gel of hectorite was formed. The XRD pattern of the synthesized one was coincided with that of natural hectorite and SEM study revealed uniform grains 50 m in diameter. The d001 basal spacing of the product moved from 12 to $17.4\;{\AA}$ after glycolation treatment. The measured value of CEC and the swelling capacity was 90 cmol/kg and $60{\sim}70\;mL/2\;g$, respectively.