• Asian Pacific Journal of Cancer Prevention
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• 제15권12호
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• pp.4919-4923
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• 2014

Background: To investigate the effect of celecoxib on telomerase activity and apoptosis in a human laryngeal squamous carcinoma cell line (Hep-2 cells). Materials and Methods: The growth inhibition rate of Hep-2 cells in vitro was measured by MTT assay, and apoptosis by TUNEL assay and flow cytometry (FCM). The TRAP-ELISA method was used to determine telomerase activity in Hep-2 cells. The mRNA expression of human telomerase RNA component(hTR), human telomerase reverse transcriptase (hTERT) and human telomerase-associated protein(hTEP1) was determined by RT-PCR assay. Expression of Bax and Bcl-2 proteins was assessed by Western blotting. Results: Celecoxib can inhibit proliferation and induce apoptosis in a dose- and time-dependent manner, repress telomerase activity, decrease hTERT mRNA and Bcl-2 protein expression and increase Bax protein expression, PGE2 had no effect on telomerase. Conclusions: Celecoxib had the antiproliferative and pro-apoptotic effect in Hep-2 cells. Apoptosis was accompanied by a decrease in telomerase activity which was directly correlated with hTERT mRNA and up-regulation of Bax/Bcl-2. Bcl-2 may thus play an important role in telomerase activity as well as apoptosis.

• Toxicological Research
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• 제33권2호
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• pp.119-124
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• 2017

Hexavalent chromium is a bio accumulative toxic metal in water and fish. It enters aquaculture ponds mainly through anthropogenic sources. Hexavalent chromium concentrations and its effects on the morphology and behavior of Clarias gariepinus were investigated from four aquaculture ponds for 12 weeks. Chromium was measured using diphenyl carbohdrazide method; alkalinity and hardness were measured using colometric method and analyzed with Bench Photometer. Temperature and pH were measured using pH/EC/TDS/Temp combined tester. Temporal and spatial replications of samples were done with triplicates morphological and behavioural effects of the metal on fish were observed visually. Chromium ranged from no detection to 0.05 mg/L, alkalinity 105 to 245 mg/L, hardness 80 to 165 mg/L, pH 6.35 to 8.03 and temperature 29.1 to $35.9^{\circ}C$. Trend in the chromium concentrations in the ponds is natural > earthen > concrete > collapsible. There was a significant difference (P < 0.05) in chromium, alkalinity, water hardness, pH and temperature among the four ponds. Significant positive correlation also existed between alkalinity, water hardness, pH, with chromium. Morphological and behavioural changes observed in the fish include irregular swimming, frequent coming to the surface, dark body colouration, mucous secretion on the body, erosion of gill epithelium, fin disintegration, abdominal distension and lethargy. High chromium concentration in natural pond was due to anthropogenic run-off of materials in to the pond. Acidic pH, low alkalinity, low water hardness also contributed to the high chromium concentration. Morphological and behavioural changes observed were attributed to the high concentrations, toxicity and bio accumulative effect of the metal. Toxicity of chromium to fish in aquaculture could threaten food security. Watershed best management practices and remediation could be adopted to reduce the effects of toxicity of chromium on pond water quality, fish flesh quality and fish welfare.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1997년도 하계학술대회 논문집 F
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• pp.1968-1970
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• 1997

유도전동기의 속도 제어 장치로 인버터의 사용이 두드러지고 있으며, 소용량 가변속 드라이브에 있어서 그 제어성의 양호한 범용 인버터 구동이 현 인버터 시장의 주류를 이루고 있다. 그러나 범용 인버터는 종래의 TR구동 인버터에 비해 스윗칭 횟수가 많고 데드타임의 영향이 크게 나타난다. 본 논문에서는 유도전동기를 운전하는 범용인버터에 대하여 데드타임으로 인한 문제 해결 및 전류 왜곡 개선 방법을 제안하였고, 이를 실험적인 결과로 입증하였다.

• Toxicological Research
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• 제23권1호
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• pp.19-24
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• 2007

We demonstrate that paclitaxel, an antitumor agent derived from yew tree, inhibits LPS- and $IFN-{\gamma}$-induced NF-kB/Rel activation in RAW 264.7 cells. Previously, paclitaxel ($>10{\mu}M$) has been known to induce iNOS gene expression in macrophages. However, in the previous report we described that the pretreatment of macrophages with low concentration of paclitaxel ($0.1{\mu}M$) for 8 h inhibited LPS-induced iNOS gene expression. Pretreatment of RAW 264.7 cells with paclitaxel significantly inhibited NF-kB/Rel transcriptional activation. Electrophoretic mobility shift assay further confirmed that pretreatment of macrophages with paclitaxel inhibited NF-kB/Rel DNA binding. Taxotere, a semisynthetic analog of paclitaxel, also inhibited LPS- and $IFN-{\gamma}$-induced iNOS gene expression. Collectively, these series of experiments indicate that paclitaxel inhibits iNOS gene expression by blocking NF-kB/Rel activation.

• Toxicological Research
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• 제23권1호
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• pp.47-53
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• 2007

Amygdalin is a cyanogenic glycoside which is commonly found in almonds, bamboo shoots, and apri-cot kernels, and peach kernels. Amygdalin was first hydrolysed into prunasin, then degraded into cyanohydrin by sequential two-stage mechanism. The objective of this study was to examine the amygdalin decomposition and cyanide formation at various in vitro conditions, including acid, enzyme and anaerobic microbes (AM) in human feces (HF). In acid hydrolysis mimicking gastric environment, amygdalin was degraded to cyanide up to 0.2% in specific pH. In contrast, enzyme assay showed higher cyanide generation either by ${\beta}$-glucosidase, or by incubation with microbe. In conclusion, we are convinced of cyanide generation are occurred mainly by microbiological activities of the gut flora up to 41.53%. After ingestion with some staff, the degree and site of degradation in an organism is a key parst of regulatory decision making of that staff.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2006년도 제37회 하계학술대회 논문집 A
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• pp.81-82
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• 2006

본 논문에서는 765kV 변전소 건설시 최초로 도입된 시운전 시험을 중심으로 기술하였다. 시운전 시험은 765kV 초기 가압 및 상업 운전에 대비하여 사전에 문제점을 도출하고, 이에 대한 대책을 강구하기 위한 목적으로 시행되었다. 2004년에 시행한 신가평변전소에 대한 전력계통시험분야의 시운전시험을 중심으로 기술하였다. 기존의 345kV전력설비와 765kV전력설비(800kVGIS, 765kV7M.Tr)의 보호방식 차이에 따른 시험 방법, 시험 시 발생된 문제점 및 시험 결과에 대해 기술하였다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2002년도 추계학술대회 논문집 전력기술부문
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• pp.29-31
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• 2002

Purpose of the 765kV trial operation conducted for the first time in our country are performance verification of domestic developed equipment(765kV M.Tr, GIS,etc) and extraction of problem in advance to commercial operation and cultivation of operation ability. The trial operation of 765kV substation was finished successfully under the positive supports of institutes. manufactures. and constructers. It is expected that extraction of problems in advance and accumulation of operation techniques through the trial operation of 765kV substation will be contributed largly to the realization of the without a hitch operation of 765kV system.

• Toxicological Research
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• 제29권4호
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• pp.257-261
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• 2013

${\alpha}$-Curcumene is one of the physiologically active components of Curcuma zedoaria, which is believed to perform anti-tumor activities, the mechanisms of which are poorly understood. In the present study, we investigated the mechanism of the apoptotic effect of ${\alpha}$-curcumene on the growth of human overian cancer, SiHa cells. Upon treatment with ${\alpha}$-curcumene, cell viability of SiHa cells was inhibited > 73% for 48 h incubation. ${\alpha}$-Curcumene treatment showed a characteristic nucleosomal DNA fragmentation pattern and the percentage of sub-diploid cells was increased in a concentration-dependent manner, hallmark features of apoptosis. Mitochondrial cytochrome c activation and an in vitro caspase-3 activity assay demonstrated that the activation of caspases accompanies the apoptotic effect of ${\alpha}$-curcumene, which mediates cell death. These results suggest that the apoptotic effect of ${\alpha}$-curcumene on SiHa cells may converge caspase-3 activation through the release of mitochondrial cytochrome c.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1990년도 가을 학술발표회 논문집
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• pp.151-156
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• 1990

This is an experimental study to investigate chante of early strength of polymer concrete due to curing temperature change. Polymer binders that were used in the experiment include 2 types of epoxy system and 4 types of polyester system which are commercially producer in Korea. The study result showed that there was a difference in early strength by curing temperature. At $35^{\circ}C$ which is a higher than normal curing temperature, higher strengths were developed in polymer concretes prepared with KB-Clear and YD-128 of epoxy system, and G-550 and H-660 of polyester system. However, at the same temperature, reduced strengths were obtained for FH-103 and TR-132 of polyester system. Further study under various curing conditions with humidity and temperature change will warrant more generalized result.

• Toxicological Research
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• 제28권4호
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• pp.249-253
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• 2012

In this study, we prepared alcohol extracts of the larva, pupa, queen, and cocoon (clony) of B. ignitus, B. terrestris, and B. h. sapporoensis, and tested the anti-inflammatory activity of the extracts by using a rat model of adjuvant-induced edema. The extracts derived from the queen of B. ignitus, the queen of B. terrestris, and the cocoon of B. ignitus decreased hind paw edema after 1 day of i.p. administration. These extracts also induced vasorelaxation and NO production in calf pulmonary artery endothelial cells. These results suggest that bumblebee alcohol extracts has anti-inflammatory and vasorelaxant properties.