• Proceedings of the Korean Vacuum Society Conference
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• 2013.02a
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• pp.411-412
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• 2013

최근 UV LED는 생화학 및 의료 산업에서 많은 각광을 받고 있다. 특히, 360nm 이하의 파장대를 갖는 UV LED는 치료 기술, 센서, 물이나 공기 등의 정화와 같은 목적으로 특별한 관심이 쏠리고 있다 [1]. 이러한 지속적인 연구를 통하여 현재까지 UV LED는 거대한 성장을 이루어 왔다. 하지만 이러한 노력에도 불구하고, 360 nm 이하의 UV LED는 여전히 오믹 접촉과 전류 분산이 원활하지 못하다는 문제점을 가지고 있다. 이것은 UV LED의 외부 양자 효율을 감소시키고, 더 나아가 극도로 낮은 광 추출 효율을 초래한다. 최근 이러한 문제를 해결하고자, 투명 전도성 산화물(TCO)을 금속 전극과 p-AlGaN 사이에 삽입해주는데, 현재 가장 널리 사용되는 TCO 물질은 ITO 이다 [2]. 하지만 ITO 물질은 상대적으로 작은 밴드갭(3.3~4.3 eV)과 단파장 빛이 가지는 큰 에너지로 인하여 deep-UV 영역에서는 빛이 투과하지 못하고 대부분 흡수된다 [3]. 따라서 본 연구에서는 기존의 박막형 ITO 투명 전극에 비해 투과도 손실을 최소화할 수 있는 mesh, grid 기반의 투명전극을 연구하였다. Fig. 1과 같이 $5{\mu}m$, $10{\mu}m$, $20{\mu}m$ 간격으로 이루어진 mesh, grid 구조의 투명전극을 구현하여 투과도 손실을 최소화하면서 우수한 전기적 특성을 확보하기 위한 구조 최적화 연구를 진행하였다. 본 연구를 위해 mesh, grid 구조의 ITO 전극 패턴을 photolitho 공정으로 형성하였으며, e-beam 증착법으로 60 nm 두께의 ITO 전극을 형성 후 질소 분위기/$650^{\circ}$에서 30초 동안 RTA 공정을 진행하였다. Fig. 1에서 볼 수 있듯이 mesh, grid의 간격이 증가할수록 투명 전극이 차지하는 면적이 감소하여 투과도는 향상되는 반면, 투명 전극과 p-GaN과의 접촉 면적 또한 감소하므로 오믹 특성이 저하된다. 따라서 투과도 손실을 최소화하면서 우수한 전기적 특성을 확보하기 위해 mesh는 $20{\mu}m$, grid는 $10{\mu}m$ 간격의 구조로 각각 최적화하였다. 그 결과 박막 기반의 ITO 투명전극 대비 최대 약 10% 향상된 투과도를 확보하였으며, I-V Curve 결과를 통하여 p-GaN 기판과 mesh 구조의 ITO 전극 사이에 박막 기반의 투명 전극과 비슷한 수준인 $0.35{\mu}A(@5V)$의 전기적 특성을 확보하였다. 결과적으로 mesh, grid 기반 투명전극의 구조 최적화를 통하여 p-GaN과 원활한 오믹 접촉을 형성하는 동시에 기존 박막형 ITO 투명 전극 구조보다 높은 투과도를 확보할 수 있었다.

• Analytical Science and Technology
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• v.15 no.1
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• pp.72-79
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• 2002

Di-(2-ethylhexyl)phthalate (DEHP) may be released from plasticized poly(vinyl chloride) (PVC) articles. In the cases of various methods for the quantitative analysis of migrating DEHP, there are much differences in migrating quantity according to the experimental methods. It is therefore important to make the comparison and analysis between these two results. A study of DEHP migration from blood and infusion bags has been carried out in different methods to evaluate the amount of DEHP migration using gas chromatograph and UV-vis spectrophotometry. Five PVC bags were cut into plane sheets in size of $40{\times}10{\times}0.4mm$, then were immersed in extraction solvent for an hour to release DEHP. It was determined by a gas chromatograph that $23.2{\sim}70.9{\mu}g/mL$ of DEHP was extracted. While extraction solvent was injected into PVC bags which were then placed for an hour to leach DEHP out. It was checked by a UV-vis spectrophotometer that the concentration of DEHP in extraction solvent was $24.8{\sim}41.3{\mu}g/mL$. Two results show different values according to the extraction conditions and experimental methods and the gas chromatographic results were converted into UV-vis spectroscopic results on condition that DEHP would be extracted equally per unit time and unit contact area. It was concluded that DEHP migrating amounts are approximately equal in two analytical methods.

• Applied Biological Chemistry
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• v.49 no.1
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• pp.55-59
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• 2006

This study was designed to investigate the optimum manufacturing condition of germanium-fortified yeast, and the binding properties of germanium (Ge) in germanium-fortified yeast. The nutritional optimum conditions were glucose 3.0 (w/v) %, yeast extracts 0.3 (w/v) % and peptone 0.5 (w/v) %, and the amounts of yeast cells were 67.4 mg/ml. And, the standard germanium-fortified yeast was produced under the condition at the ratio of yeast cell and germanium solution was 1 : 0.5 (50%), pH 6.5 and $35-40^{\circ}C$ during fermentation. In results of the identification, binding of germanium-protein showed structural difference between the inorganic Ge $(GeO_2)$ added during fermentation process and germanium-fortified yeast. Therefore, germanium-fortified yeast made by biosynthetic technology formed structurally safe organic germanium during fermentation process. Germanium-fortified yeast can be applied as a new functional material far the improvement of health, the prevention and treatment of chronic degenerative disease like cancer, and the enforcement of immune system.

• Microbiology and Biotechnology Letters
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• v.37 no.3
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• pp.197-203
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• 2009

An indole oxygenase originated from Rhodococcus sp. RHA1 was cloned into the expression vector, pTrc99A, in Escherichia coli, and designated pTCAN1. The pTCAN2 was constructed from pTCAN1 by the deletion of $lacI^q$ for the constitutive expression of indole oxygenase without adding IPTG in the medium. The complete open reading frame of indole oxygenase was 1,224 bp long, which encodes a protein of 407amino acids. Crude extracts of E. coli $DH5{\alpha}$/pTCAN1 and pTCAN2, respectively, were prepared and subjected to SDS-PAGE analysis. A band corresponding to molecular mass of about 43 kDa was appeared and this result correlated with the predicted molecular mass of cloned indole oxygenase. The E. coli harboring pTCAN1 and pTCAN2, respectively, showed blue color colony in LB plate. The pigment showing blue color was prepared from E. coli $DH5{\alpha}$/pTCAN2, and identified as indigo by experiments using spectrophotometer, HPLC, and TLC. The indigo-forming activity of indole oxygenases from the whole cell of E. coli $DH5{\alpha}/pTCAN1$ cultured at LB medium added 1mM of IPTG and that of E. coli/pTCAN2 showed about 1.75nmol/min/mg DCW (dry cell weight) and 3.85 nmol/min/mg DCW, respectively. Also, the E. coli $DH5{\alpha}$/pTCAN2 produced about $236{\mu}M$ of indigo after 48 hours incubation in TB medium supplemented with 2.5 mM of tryptophan.

• Journal of Veterinary Clinics
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• v.25 no.4
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• pp.249-256
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• 2008

This experiment was conducted to investigate antitumor and immunomodulatory effects of Artemisia capillaris extracts against Hepa-lc1c7 and Sarcoma 180 cancer cells. In in vivo experimental tests using 210 ICR mice, on the $28^{th}$ day and the $42^{nd}$ day, all animals in vehicle controled HP (Hepa-lclc7 tumor cell inoculated vehicle control) and SP (Sarcoma 180 tumor cell inoculated vehicle control) showed tumor cells in the liver and spleen based on the histopathology. However, the incidences and the percentages of regions occupied by tumor cells were dramatically and dose-dependently decreased by mACH (Artemisia capillaris methanol extracts) treatment on the histomorphometry. Although the exact mechanism of inhibition of the incidences of tumor cells in the parenchyma whether inhibition of metastasis or proliferation is unclear, mACH dramatically reduce the percentages of regions occupied by tumor cells in the liver and spleen apart from the inoculation sites of Hepa-lclc7 and Sarcoma 180. In addition, they also effectively inhibit the abnormal changes on the kidney detected in the present study. The results suggest that Artemisia capillaris methanol extracts have prominent antitumor effects on the cancer cell lines Hepa-lclc7 and Sarcoma 180 m mice.

• Journal of Veterinary Clinics
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• v.28 no.1
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• pp.20-27
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• 2011

Hovenia dulcis Thunb (HDT) has been known folk medicine and has been used as therapeutic drug in the treatment of liver disease. Also it has been used as a detoxifying agents for alcoholic poisoning and promoting diuresis. However, there has not been any study on therapeutic effect of Hovenia dulcis extract on $CCl_4$ induced liver and kidney damage in rats. In this study, we report on therapeutic effects of Hovenia dulcis extract on $CCl_4$ induced liver and kidney damage in rats. Rats were divided into four groups of eighteen animals. Control group (DW) was administrated with distilled water 2.5 mL/kg per peritonial administration and then $CCl_4$ group (CCl) was administrated $CCl_4$ 2.5 mL/kg per peritonial administration, $CCl_4$+HDT extract group ($CCl_4$+HDT) was administrated HDT extrat (100 mg/kg) after $CCl_4$ 2.5 mL/kg administration, $CCl_4$+Silymarin group ($CCl_4$+Sily) was administrated Silymarin (50 mg/kg) after $CCl_4$ 2.5 mL/kg administration. The complete blood cell (CBC) count of RBC, WBC, PCV, Hb, MCH, MCV, MCHC and blood chemistry profile of AST, ALT, GGT, ALP, Total choloesterol, Tryglyceride, Total bilirubin, Amylase, Glucose, BUN, Creatinine, Lipase and pathologic changes were observed for 7 days after administration of D.W., $CCl_4$, $CCl_4$+HDT extract, $CCl_4$+Silymarin. The results are as follows : 1. RBC and PCV were significantly (p < 0.01) increased in all groups compared to D.W. but hemoglobin, MCH, MCV and MCHC were not showed significant difference during experimental periods. 2. AST, ALT, T-cholesterol, T-bilirubin, TG were significantly (p < 0.05) increased in all groups on day 3 compared to D.W. and were normal on day 7. 3. ALP was significantly (p < 0.05) decreased in $CCl_4$+HDT group on day 3 but Amylase was not showed significant difference during experimental periods. 4. BUN was significantly (p < 0.05) increased in $CCl_4$ group on day 7, but $CCl_4$+HDT group and $CCl_4$+Sily group were normal. Creatninie was significantly (p < 0.05) increased in $CCl_4$ group on day 3 and normal on day 7 but $CCl_4$+HDT group and $CCl_4$+Sily group were not showed significant difference during experimental periods.

• Journal of Veterinary Clinics
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• v.26 no.1
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• pp.1-7
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• 2009

The Artemisia capillaris THUNB is a perennial herb that belongs to the family Compositae spp and probably the most common plant among the various herbal folk remedies being used in the treatment of abdominal pain, hepatitis, chronic liver disease, jaundice and coughing in Korea. Recently the biological and pharmacological actions of herb have been studied well such as antibacterial, antidiabetic and antitumor activities. This experiment was conducted to investigate antitumor and immunomodulatory effects of Artemisia capillaris extracts against Hepa-1c1c7 and Sarcoma 180 cancer cells in in vivo experimental tests. In in vivo experimental tests using 210 ICR mice, based on flow cytometry, CD3+, CD4+, CD8+ and TNF-${\alpha}+$ splenocytes were significantly (p<0.05) reduced in the Hepa-1c1c7 and Sarcoma 180 inoculated vehicle controls, HP and SP, compared to those of the intact vehicle control on both the $28^{th}$ day and the $42^{nd}$ day, respectively. These decreases of CD3+, CD4+, CD8+ and TNF-${\alpha}+$ cells induced by tumor inoculations were significantly (p<0.05) inhibited by mACH treatment regardless of the type of experiments and tumor cells inoculated. The results suggest that Artemisia capillaris methanol extracts have prominent antitumor effects on the cancer cell lines Hepa-1c1c7 and Sarcoma 180.

• Journal of Periodontal and Implant Science
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• v.31 no.1
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• pp.149-165
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• 2001

This study was performed to define the cytotoxicity and the anti-inflammatory action of Pulsatilla koreana extracts. To analyze cytotoxic effects, gingival and periodontal ligament fibroblasts were used, and anti-inflammatory actions related to reduction of $IL-1{\beta}$ and $PGE_2$ production were performed in vitro, for the suggestion of efficacy and safety on periodontal therapeutic use of Pulsatilla koreana extracts. We extracted ethylacetate and butylalcohol from well-dried and ground Pulsatilla koreana throughout multiple processing, then used different concentration solution(0.1 %, 0.2 %, 0.4 %, 0.01 %, 0.02 %, 0.04 %, 1 %, 2 %) of ethylacetate and butylalcohol extracts to examine eytotoxic effects and anti-inflammatory actions Cytotoxic effects were examined by ELISA reader using MTT(Methyl Thiazol-2-YL-2, 5-diphenyl Tetrazolium bromide)solution following culture of human gingival and periodontal ligament fibroblasts. Synthesis of $IL-1{\beta}$was examined by $IL-1{\beta}$ enzyme-immunoassay(EIA)system after separation and culture of monocyte, and $PGE_2$ was examined by $PGE_2EIA$ system after culture of gingival fibroblasts. The results were as follows: 1. In the MTT test of gingival fibroblasts, the change of optical density was decreased significantly at 2 % of butylalcohol extracts and 0.04 %, 0.1 %, 0.2 %, 0.4 %, 1 %, 2 % of ethylacetate extracts.(p<0.05) 2. In the MTT test of periodontal ligament cells, the change of optical density were not differ significantly. but butylalcohol and ethylacetate extracts except from butylalcohol 0.01 % showed high cell cytotoxity. 3. Both ethylacetate and butylalcohol extracts from Pulsatilla koreana inhibited the synthesis of $IL-1{\beta}$and inhibition effect of ethylacetate extracts were higher than butylalcohol extracts. 4. Both ethylacetate and butylalcohol extracts from Pulsatilla koreana inhibited the synthesis of $PGE_2$, and ethylacetate extracts were higher than butylalcohol extracts. In conclusion, ethylacetate and butylalcohol extracts from Pulsatilla koreana showed little cell cytotoxity for gingival and periodontal ligament fibroblasts, and the inhibition of $IL-1{\beta}$ and $PGE_2$ sysnthesis, therefore it is considered that these extracts can be developed as the therapeutics of the periodontal disease.

• Journal of the Korean Society of Food Science and Nutrition
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• v.43 no.10
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• pp.1535-1542
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• 2014

This study was conducted to investigate the physicochemical properties and biological activities of collagens with different molecular weights from Alaska pollack (Theragra chalcogramma) skin as well as their efficacies as functional materials. The molecular weights of collagens were between 1~10 kDa (below 1 kDa (AP1), 1~3 kDa (AP2), 3~10 kDa (AP3), and above 10 kDa (AP4). The protein content of AP4 (40.19 g/100 g) was the highest. Collagen contents of AP1, AP2, AP3, and AP4 were 36.43, 32.23, 19.23, and 14.89%, respectively. The free amino acid and essential amino acid contents of AP1 were higher than those of AP2, AP3, and AP4. Fourier transform infrared spectroscopy spectra of collagens with different molecular weights showed wavenumbers representing the regions of amide I, amide II, amide III, and amide A, respectively. The electron-donating ability (29.51%) and SOD-like activity (38.45%) of AP1 were higher than those of AP2, AP3, and AP4. Tyrosinase inhibition activity of AP1 improved with higher treatment concentration. The rate of inhibition of MMP-1 production in HS68 cells exposed to UVB was suppressed by treatment with AP1 (29.78%) and AP2 (26.49%) at 1 mg/mL. Furthermore, there was a strong correlation between DPPH, superoxide dismutase, tyrosinase activity, and MMP-1 inhibition rate of collagens with different molecular weights.

• Journal of Life Science
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• v.27 no.6
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• pp.680-687
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• 2017

Recently, there has been a marked increase in the use of bioactive products resulting from the fermentation of natural substances by microorganisms. In this study, Opuntia humifusa (OH) was fermented using Lactobacillus plantarum (fermented Opuntia humifusa; fOH). We then examined the anti-obesity effect of fOH in mice fed a 45% Kcal high fat diet (HFD). In this study, mice were treated with fOH concentrations of 100, 200, and 400 mg/kg. The mice in the control group were treated with OH at a concentration of 400 mg/kg based on previous animal experiments. All of the mice given a continuous HFD showed an increase in their weight, the density of abdominal fat, and the accumulated periovaric and abdominal fat. All of these obesity-linked factors, however, were significantly decreased in the groups treated with fOH at concentrations of 200 and 400 mg/kg. Mice treated with fOH at 100 mg/kg did not show a significant decrease in these obesity-linked factors compared to the control group. It appears that fOH fermented by L. plantarum has a greater anti-obesity effect in HFD-supplied mice compared to unfermented OH. While further studies of fOH are needed to examine its effect on obesity, hyperlipidemia, hepatic steatosis, renal function, and type II diabetes with its relevant complications, fOH may have significant therapeutic potential in the treatment of metabolic syndrome.