• 반도체디스플레이기술학회지
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• 제17권4호
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• pp.66-69
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• 2018

This study was researched the electrical properties of semiconductor devices such as ITO, $SiO_2$, $V_2O_5$ thin films. The films of ITO, $SiO_2$, $V_2O_5$ were deposited by the rf magnetron sputtering system with mixed gases of oxygen and argon to generate the plasma. All samples were cleaned before deposition and prepared the metal electrodes to research the current-voltage properties. The electrical characteristics of semiconductors depends on the interface's properties at the junction. There are two kinds of junctions such as ohmic and schottky contacts in the semiconductors. In this study, the ITO thin film was shown the ohmic contact properties as the linear current-voltage curves, and the electrical characteristics of $SiO_2$ and $V_2O_5$ films were shown the non-linear current-voltage curves as the schottky contacts. It was confirmed that the electronic system with schottky contacts enhanced the electronic flow owing to the increment of efficiency and increased the conductivity. The schottky contact was only defined special characteristics at the semiconductor and the interface depletion layer at the junction made the schottky contact which has the effect of leakage current cutoff. Consequently the semiconductor device with shottky contact increased the electronic current flow, in spite of depletion of carriers.

• The Korean Journal of Physiology and Pharmacology
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• 제23권5호
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• pp.357-366
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• 2019

$G{\alpha}_q$-coupled receptor stimulation was implied in the activation process of transient receptor potential canonical (TRPC)1/4 and TRPC1/5 heterotetrameric channels. The inactivation occurs due to phosphatidylinositol 4,5-biphosphate ($PI(4,5)P_2$) depletion. When $PI(4,5)P_2$ depletion was induced by muscarinic stimulation or inositol polyphosphate 5-phosphatase (Inp54p), however, the inactivation by muscarinic stimulation was greater compared to that by Inp54p. The aim of this study was to investigate the complete inactivation mechanism of the heteromeric channels upon $G{\alpha}_q$-phospholipase $C{\beta}$ ($G{\alpha}_q-PLC{\beta}$) activation. We evaluated the activity of heteromeric channels with electrophysiological recording in HEK293 cells expressing TRPC channels. TRPC1/4 and TRPC1/5 heteromers undergo further inhibition in $PLC{\beta}$ activation and calcium/protein kinase C (PKC) signaling. Nevertheless, the key factors differ. For TRPC1/4, the inactivation process was facilitated by $Ca^{2+}$ release from the endoplasmic reticulum, and for TRPC1/5, activation of PKC was concerned mostly. We conclude that the subsequent increase in cytoplasmic $Ca^{2+}$ due to $Ca^{2+}$ release from the endoplasmic reticulum and activation of PKC resulted in a second phase of channel inhibition following $PI(4,5)P_2$ depletion.

• The Korean Journal of Physiology and Pharmacology
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• 제1권6호
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• pp.707-716
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• 1997

Recent reports revealed that the $Na^+-Ca^{2+}$ exchangers and feet structures of sarcoplasmic reticulum(SR) are located in close vicinity in the specific compartment. Therefore, we investigated the possibility that the $Na^+-Ca^{2+}$ exchanger may decrease the tension development by transporting the $Ca^{2+}$ out of the cell right after it released from SR, on the basis of this anatomical proximity. We exammined the negative force-frequency relationship of the developed tension in the electrically field stimulated left atria of postnatal developing rat(1, 3 day, 1 week and 4 week old after birth). Cyclopiazonic $acid(3{\times}10^{-5}\;M)$ treatment decreased the developed tension further according to postnatal age. $Monensin(3{\times}10^{-6}\;M)$ treatment did not increase the maximal tension in 4 week-old rat, preserving negative staircase, while the negative staircase in the younger rat were flattened. $Ca^{2+}$ depletion in the buffer elicited more suppression of the maximal tension according to the frequency in all groups except the 4 week-old group. The % decrease of the maximal developed tension of 4 week-old group at 1 Hz to that of 0.1 Hz after $Na^+$ and $Ca^{2+}$ depletion was only a half of those of the yonger groups. Taken together, it is concluded that the $Na^+-Ca^{2+}$ exchange transports more $Ca^{2+}$ released from SR out of the cell in proportion to the frequency, and this is responsible for the negative staircase effect of the rat heart.

• 대한기계학회논문집B
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• 제41권2호
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• pp.109-115
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• 2017

전산유체해석(CFD) 기법을 이용하여 음극 지지체형 고체산화물 연료전지(SOFC)에 대한 수치해석을 수행하였다. 평판형 구조의 SOFC 에서 가스채널과 리브폭 변화에 따른 성능과 온도균일성에 관한 연구가 이루어졌다. 전산해석 툴로서는 공개소스 전산유체해석 툴박스인 OpenFOAM 을 이용하였다. 수치해석결과, 산소고갈이 일어나지 않는 범위 내에서 가스채널과 리브폭의 증가는 성능과 온도 균일성에 크게 영향을 미치지 않음을 알 수 있었다. 하지만 넓은 리브폭의 사용과 고전류밀도에서의 작동은 산소고갈로 인한 성능저하의 가능성이 있음을 확인하였다.

• 한국식품영양과학회지
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• 제26권6호
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• pp.1173-1180
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• 1997

Hepatotoxicity of caffeine and acetaminophen was investigated in this study. Special attention was paid to the effect of vitamins on the reduction of hepatotoxicity caused by the chemicals. Rat hepaocytes isolated by two-step perfusion method were cultured in two differents methods-suspension, monolayer cultures-, and exposed to caffeine and/or acetaminophen for 24hrs. Caffeine or acetaminophen exhibited no significant hepatotoxicity in terms of intracellular glutathione(GSH) level and lipid peroxidation(MDA), but GSH level was significantly decreased after administrated acetaminophen, and the toxicity caused by the chemicals showed a dose-dependent manner. The synergistic effect of caffeine and acetaminophen was observed when both caffeine and acetaminophen were supplemented to culture medium. At the concentration 1mM, caffeine enhanced the intracellular GSH depletion and MDA formation by 63% and 64%, respectively, compared to single supplementation of 10mM acetaminophen in culture medium. This hepatotoxicity induced membrane integrity loss was observed by lightmicroscope on the simultaneous administration of caffeine and acetaminophen in monolayer cultured hepatocytes. Co-supplementation of vitamins with caffeine/acetaminophen to culture medium results in the protection of hepatocytes from hepatotoxic attach by caffeine/acetaminophen. Especially, vitamin E was superior to vitamin C and $\beta$-carotene from the standpoints of GSH depletion and MDA formation. From this results, it has been speculated that vitamin E may play a role of antioxidant scavenging radicals produced from acetaminophen. Taken all together, in vitro culture system like monolayer culture of hepatocytes may be a useful tool for the evaluation of hepatotoxicity or protection ability of food ingredients.

• 한국토양비료학회지
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• 제15권4호
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• pp.233-240
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• 1982

수도(水稻) 등숙기간중(登熟期間中) 동화산물 전류의 품종간 특성과 식물체내 무기성분조성이 동화산물 전류에 미치는 영향 등을 구명하기 위하여 표식탄소(標識炭素)($^{14}C$)를 이용, 본 시험이 실시되었다. 곡실로의 $^{14}C$ 전류와 수기충(受器充) 전속도(塡速度)는 일치하는 경향이었고 품종 및 특성은 등숙 후기전류우세형(I형 : 아끼바레), 등숙초기전류우세형(II형 ; 태백벼, 추풍벼), 중간형(III형 ; 밀양 23호, 밀양 42호, 유신)등 3群으로 분류되었다. 질소영양상태와 $^{14}C$의 곡실로의 전류간에는 역상관의 경향을 보였다. 유수형성기부터 출수기까지 인산, 가리. 석회, 고토, 및 규산의 공급중단은 곡실입중을 약 4~12% 감소시켰으나 출수기에 동화된 $^{14}C$의 곡실로의 전류를 증가시켰고 출수 후 이들 성분의 재공급효과는 인산>고토>가리, 석회의 순(順)이었으며 규산의 재공급효과는 인정하기 어려웠다. 광합성능은 질소영양에 크게 좌우되었으며 인산, 가리, 석회의 공급중단은 단엽광합성능(單葉光合成能)을 현저히 감소시켰으나 반면에 규산의 공급중단은 광합성능을 증가시켰다.

• Journal of Chest Surgery
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• 제37권5호
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• pp.391-400
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• 2004

이종간 장기이식은 즉각적이고 비가역적 초급성 거부 반응을 초래하는데 자연항체인 IgM이 주원인으로 알려져 있다. 따라서 항체를 제거하는 것이 초급성 거부반응을 감소시키는 하나의 방법이 될 수 있다. 이에 연구자들은 돼지\$\longrightarrow$ 개 이소 심장이식 모델에서 자연항체를 제거하기 위해 원심분리 후 혈장분반술(postcentrifugal plasmapheresis-PCPP)을 사용하고 수혜견의 항체 변화와 이종 심장이식 시 생존시간을 관찰하였다. 대상 및 방법: 10∼20 kg의 이계 교배시킨 돼지를 공여돈으로, 25∼30 kg의 잡종개를 수혜견으로 사용하였다. 실험군에 해당하는 수혜견은 COBE TPE plasmapheresis device(COBE Laboratories, Lakewood. CO)로 PCPP를 시행하였다. 심장이식 2일 전과 이식 당일 PCPP를 진행하였다. 대조군은 PCPP를 수행하지 않았다. 그룹 1에서는 PCPP를 1 plasma-volume(PV)을 시행하고, 2일 후 2 PV를 실시하였다. 그룹 2는 2 PV를 시행하고 2일 후 2 PV로 PCPP를 실시하였다. 돼지의 심장은 이소심장 이식법으로 수혜견의 복강내 신하(infrarenal) 대동맥과 하대정맥에 이식하였다. 수혜견 혈장내의 총 IgM과 IgG의 분석은 ELISA방법을 이용하였다. 실험에서 얻은 시료로 혈청 albumin, 전해질, 보체 활성도와 응고 인자의 변화를 관찰하였다. 또한 이식된 심장의 초급성 거부 반응을 확인하기 위해 이식 거부반응을 경험한 심장 절편을 조직 병리학적으로 관찰하였다. 결과: PCPP 방법으로 처리한 그룹 2에서의 혈장내의 총 IsM과 IgG의 제거율은 각각 95.7$\pm$1.2%, 80.5$\pm$2.4%를 나타냈다. 또한 각 그룹에서 혈청 albumin 농도가 감소하는 것을 관찰하였는데 그룹 1에서는 2.8에서 1.4g/㎗, 그룹 2에서는 3.0에서 1.5 g/㎗의 감소를 보였다. 보체 활성도는 PCPP를 시행하면 감소하였다가 PCPP시행 후 약 24시간 후면 정상으로 회복되었다. 2 PV로 2회 시행한 PCPP에서의 보체 활성도는 시행 전의 10% 수준까지 감소되었다. PCPP가 혈액응고인자에 미치는 영향을 보면 2 PV의 PCPP 시행으로 fibrinogen의 농도가 시행 전의 20% 수준 이하로 떨어졌으나 이 효과는 24시간 이내에 회복되었고 antithrombin III도 비슷한 양상을 보였으나 fibrinogen보다 소폭의 감소를 보였다. PT, aPTT는 PCPP도중에 간혹 연장되는 경우가 있었으나 늘 일정한 결과는 아니었으며 이식 후에 측정 가능 범위 이상으로 연장되었다. D-dimer의 경우 PCPP 시행 동안에는 검출되지 않았으나 이식 후 10분부터 검출되어 지속되었다. PCPP를 수행하지 않은 그룹 0 수혜견에 이식한 심장의 생존시간은 5분이었으나 PCPP에 의해 자연항체를 제거 후 이식된 심장의 생존시간은 90분으로 현저한 증가를 보였다. 또한 조직 병리학적으로도 이식 거부에 대한 특징이 그룹 0에 비해 그룹 2에서 지연됨을 확인하였다. 결론: PCPP는 수혜견의 자연항체를 효과적으로 제거하여 초급성 거부반응을 감소시킴으로써 결국 돼지의 이종 이식 전 심장의 생존시간을 증가시켰다.

• 한국식품영양과학회지
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• 제23권5호
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• pp.750-756
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• 1994

The effect of onion juice on ethanol -induced lipid peroxidation were studied were studied in rats. The contents of thiobarbituric acid (TBA) -reactants increased significantly in liver thanol(4ml/kg/day) administered -rats. The activities of serum alanine aminotransferase and alkaline phosphatase increased by ethanol administration compared with control group, but alterations of antioxidant enzymes activities in liver of ethanol administered rats were not significant vs control group. The glutathione contents in liver decreased by ethanol , whereas the glutathione level increased in ethanol and onion juice group compared with ethanol group. The contents of hepatic TBA-reactants and serum aminotrasnferase activity in ethanol group were reduced by onion juice administration. In these results, increased hepatic TBA-reactants of liver in ethanol group might be due to decreased glutathione contents in liver. Reduced glutathione (GSH) plays an important roles in the liver in several detoxification and the reduction of lipid peroxides. So the protective effects of onion juice on ethanol-induced increment of TBA-reactants may be due to the increament of lgutathions content. The glutathione depletion by ethanol was an important factor of ethanol-induced cell damage, and the prevention of onion juice to the glutathione depletion reduced by ethanol may be an important factor on the protection from ethanol-induced lipid perpxidation in rats.

• Journal of Ginseng Research
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• 제35권3호
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• pp.261-271
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• 2011

Chemical radiation protection is an important strategy to protect living beings against the deleterious effects of radiation. In the present study, the radioprotective effect of hydro-alcoholic extract of Panax ginseng extract (PGR-HAE) was studied on radiation-induced deleterious alterations in Swiss albino mice. Oral administration of such extract (25 mg/kg b wt/day/animal) for 5 consecutive days, half an h. before whole-body exposure to 6 Gy gamma radiation, enhanced the 30 days survival and also inhibited the radiogenic sickness, weight loss and life shortening. PGR-HAE ameliorated radiation induced depletion in blood constituents at different necropsy intervals between 12 h to 30 d, and significantly increased the number of femoral spleen colony forming units that survived after irradiation. Furthermore, it checked depletion of glutathione and antioxidant enzymes (superoxide dismutase, catalase, and glutathione S-transferase) as well as elevation of lipid peroxidation (LPO) level in blood and liver. The significant reduction in the yield of LPO demonstrates that PGR-HAE protects the membranes against radiation-induced oxidative damage. These findings conclude that such plant extract provides significant radioprotection, and it may be potentially valuable in the prevention of injuries caused during planned and unplanned radiation exposure.

• BMB Reports
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• 제28권5호
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• pp.392-397
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• 1995

The effect of N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) on the intracellular $Ca^{2+}$ level was studied in NIH3T3 fibroblast cells. A reduction of the intracellular $Ca^{2+}$ level was observed after exposure to 300 ${\mu}m$ MNNG. However, the intracellular level of $IP_3$, a well-known regulator of $Ca^{2+}$ release from internal storage, was not changed by MNNG treatment. Instead, a reduction of the intracellular NAD level was observed. NAD as well as $IP_3$ stimulated intracellular $Ca^{2+}$ release from permeabilized cells. The treatment of 3-aminobenzamide, which inhibited the MNNG-induced reduction of the NAD level, also prevented the MNNG-induced decrease of the $Ca^{2+}$ level. Our data suggest that MNNG reduces the intracellular $Ca^{2+}$ level by NAD depletion in NIH3T3 cells.