• 대한안전경영과학회지
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• 제14권1호
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• pp.43-51
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• 2012

This study was carried out to observe the impacts of a mouse's inhalation of toxic gas SO2 generated from combustion on its organs by different concentrations. As for research methods: First, after concentrations of SO2 generation from combustion had been set to three: low (10.4 ppm), middle (24.9 ppm) and high (122 ppm) through Gas Toxicity Testing Method (KS F 2271) and SO2 combustion gas was exposed to eight mice in each concentration. Five mice that were able to move based on LD50, a criterion, which sets the down time of a mouse's average behaviors to over 9 minutes, were randomly selected in each concentration, and they were set up as the subjects of the study on toxicity bio-markers. Second, tissues were taken from heart, liver, lungs, spleen and the thymus gland of the mice selected in each concentration and a pathological examination of them was carried out. As a result, microvascular congestion appeared in the heart, and cell necrosis, cortex congestion and tubule medulla congestion, etc. in each concentration were observed in addition to vascular congestion in liver, lungs, spleen and the thymus gland. Also, it was found that the higher the concentrations of SO2 exposure is, the greater, the changes in the organs get. Through this study, SO2 of various toxic gases generated from fire turned out to affect the tissues of each organ of a mouse, it is expected that the toxic gases may greatly affect human body in case of actual fire, and this study is evaluated as having a significance as a basic data on inhalation toxicity assessment of toxic substances generated in combustion.

• 한국식품과학회지
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• 제32권1호
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• pp.200-205
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• 2000

췌장에서 분비되는 cholesterol esterase(CEase)와 소장의 acyl coenzyme A: cholesterol acyltransferase(ACAT)는 흡수된 콜레스테롤을 다시 ester화하는데 관여한다. 한방재료 중 건위, 진토 및 수렴지사작용 등을 가지는 초두구(Alpiniae Katusumadaii Semen)의 에탄올 추출물이 in vitro에서 cholesterol esterase활성에 대하여 강한 저해작용을 보였으며 에탄올추출물의 용매분획 중 클로로포름분획이 다른 분획들, 즉 에틸 아세테이트분획, 부탄올분획 및 물 분획보다 강하였다. 초두구의 클로로포름분획이 고 콜레스테롤식이를 섭취시킨 rat에서 혈중 콜레스테롤치를 저하시키는 효과가 있는지 측정한 실험에서 chloroform분획을 100 mg/kg 및 150 mg/kg 섭취시켰을 경우 각각 총cholesterol 함량이 11.8% 및 20.8% 감소하였으며 HDL-cholesterol 함량 및 동맥경화지수는 정상군에 가깝게 회복된 것으로 나타났다. 또한 초두구 chloroform분획의 독성검사 결과 mouse에서 $LD_{50}$은 1,625mg/kg으로 산출되었다.

• 한국진공학회:학술대회논문집
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• 한국진공학회 1999년도 제17회 학술발표회 논문개요집
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• pp.120-120
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• 1999

III-nitride계 물질들은 blue와 UV 영역의 LED, LD와 같은 광소자뿐만 아니라 HBT, FET와 같은 전자소자로도 널리 응용되고 있다. 이와 같은 물질을 이용한 소자를 제작할 수 있는 낮은 저항의 ohmic contact은 필수적이다. Al이나 Ti와 같은 물질을 기초로 한 n-GaN의 경우는 이미 많은 연구결과가 발표되어 전기적 광학적 소자를 동작하는데 충분히 낮은 ohmic contact저항( )을 었다. 그러나 p-GaN의 ohmic contact은 아직까지 많은 문제점을 내포하고 있다. 그 중의 하나는 높은 doping 농도( )의 p-GaN 박막을 성장하기가 어렵다는 것이며, 또 하나는 낮은 접촉 비저항을 얻기 위해선 7.5eV이상의 큰 재가 function을 지닌 금속을 선택해야 한다. 그러나 5.5eV 이상의 재가 function을 갖는 금속은 존재하지 않는다. 위와 같은 문제점들은 p-GaN의 접촉 비저항이 이상의 높은 값을 갖게 만들고 있으며, 이에 대한 해경방안으로는 고온의 열처리를 통하여 p-GaN와 금속 사이에서 화학적 반응을 일으킴으로써 표면 근처에서 캐리어농도를 증가시키고, 캐리어 수송의 형태가 tunneling 형태로 일어날 수 있도록 하는 tunneling current mechanism을 이용하는 것이다. 이로 인해 결국 낮은 접촉 비저항을 얻을 수 있게되며, 일반적으로 p-GaN에서는 Nidl 좋은 물질로 알려져 있다. 그러나 Ni은 50$0^{\circ}C$이상의 열처리에서 쉽게 산화되는 특성 때문에 높은 캐리어를 얻는데 어려운 문제점이 있다. 이에 본 연구에서는 MBE로 성장된 p-GaN박막을 Mg의 activation을 더욱 증가시키기 위해 N2 분위기에서 15분간 90$0^{\circ}C$에서 annealing을 하였으며, ohmic 접촉을 위한 금속으로 높은 재가 function과 좋은 adhesion 그리고 낮은 자체저항을 가지고 있는 Ni/Au를 ohmic metal로 하여 contact한 후에 90$0^{\circ}C$에서 10초간 rapid thermal annealing (RTA)처리를 했다. 성장된 박막의 광학적 성질은 PL로써 측정하였으며, photoconductivity 실험을 통해 impurity의 life time을 분석하였고, persistent photoconductivity를 통해 dark current를 측정하였다. 또한 contact resistance를 계산하기 위해 circular-TLM method을 이용하여 I-V 특성을 조사하였다.

• Journal of Microbiology and Biotechnology
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• 제17권2호
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• pp.325-334
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• 2007

Recently, quorum sensing has been implicated as an important global regulator controlling the production of numerous virulence factors such as capsular polysaccharides in bacterial pathogens. The nucleotide and deduced amino acid sequences of smcR, a homolog of V. harveyi luxR identified from V. vulnificus ATCC29307, were analyzed. The amino acid sequence of SmcR from V. vulnificus was 72 to 92% similar to those of LuxR homologs from Vibrio spp. Functions of SmcR were assessed by the construction of an isogenic mutant, whose smcR gene was inactivated by allelic exchanges, and by evaluating its phenotype changes in vitro and in mice. The disruption of smcR resulted in a significant alteration in biofilm formation, in type of colony morphology, and in motility. When compared with the wild-type, the smcR mutant exhibited reduced survival under adverse conditions, such as acidic pH and hyperosmotic stress. The smcR mutant exhibited decreased cytotoxic activity toward INT 407 cells in vitro. Furthermore, the intraperitoneal $LD_{50}$ of the smcR mutant was approximately $10^2$ times higher than that of parental wild-type. Therefore, it appears that SmcR is a novel global regulator, controlling numerous genes contributing to the pathogenesis as well as survival of V. vulnificus.

• Journal of Microbiology and Biotechnology
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• 제21권7호
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• pp.719-727
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• 2011

Botulism is a neuroparalytic disease caused by Clostridium botulinum, which produces seven (A-G) antigenically diverse neurotoxins (BoNTs). BoNTs are the most poisonous substances known to humans, with a median lethal dose ($LD_{50}$) of approximately 1 ng/kg of body weight. Owing to their extreme potency and lethality, they have the potential to be used as a bioterrorism agent. The mouse bioassay is the gold standard for the detection of botulinum neurotoxins; however, it requires at least 3-4 days for completion. Attempts have been made to develop an ELISA-based detection system, which is potentially an easier and more rapid method of botulinum neurotoxin detection. The present study was designed using a synthetic gene approach. The synthetic gene encoding the catalytic domain of BoNT serotype B from amino acids 1-450 was constructed with PCR overlapping primers (BoNT/B LC), cloned in a pQE30 UA vector, and expressed in an E. coli M15 host system. Recombinant protein production was optimized at 0.5 mM IPTG final concentration, 4 h post induction, resulting in a maximum yield of recombinant proteins. The immunogenic nature of the recombinant BoNT/B LC protein was evaluated by ELISA. Antibodies were raised in BALB/c mice using various adjuvants. A significant rise in antibody titer (p<0.05) was observed in the Alum group, followed by the Titermax Classic group, Freund's adjuvant, and the Titermax Gold group. These developed high-titer antibodies may prove useful for the detection of botulinum neurotoxins in food and clinical samples.

• 한방안이비인후피부과학회지
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• 제14권2호
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• pp.118-124
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• 2001

The single dose toxicity of Injinhotang, a herbal drug for treatment of hepatic injuries. was evaluated in Sprague-Dawley rats. Injinhotang was once administered to both sexes of rats at the dose levels of 2000, 1000, 500, 250 and 125 mg/kg for oral route. After single administration, clinical signs were observed every day for 14 days and body weights were measured 5 times including initial measurement on day 0 (the days of administration). When observation period was over, the animals were sacrificed and macroscopic examination of major organs was conducted. In addition, the histopathological profiles of these major organs were also conducted. Neither significant clinical signs nor death after administration was observed during the observation periods except for soft feces or diarrhea. In addition, no abnormal necropsy findings, changes of body weight and histopathological profiles were observed at terminal necropsy in both sexes. From these results, it is considered that $LD_{50}$ of Injinhotang is over 2000 mg/kg in oral administration in both sexes of rats.

• 동의생리병리학회지
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• 제26권1호
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• pp.19-25
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• 2012

This study was designed to investigate the effects of a new herbal medicine named CWS-A on the changes in regional cerebral blood flow (rCBF) and mean arterial blood pressure (MABP) in normal rats, and further to determine the mechanism of action. Also, this study was designed to investigate the effects of CWS-A on the changes in rCBF in cerebral ischemic rats and the safety examination of CWS-A in rats regared to body weight change, renal and liver function test, CBC, $LD_{50}$ and histological observation in rats. The rCBF was significantly and stably increased and MABP was significantly decreased by CWS-A during the period of cerebral reperfusion in normal rats. However, there were no here were no significant changes of rCBF in ischemic rats. In additional, there were no significant changes on the safety examination. In conclusion, these results suggest that medication of CWS-A is effective for the improve the cerebral blood flow and CWS-A can be prescribed as vertigo(眩暈) symptoms treatment.

• 동의생리병리학회지
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• 제25권2호
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• pp.242-245
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• 2011

Socheongryong-tang has been used for the treatment of inflammatory allergic diseases such as allergic rhinitis and bronchial asthma in Asian countries. This study was conducted to investigate the safety of Socheongryong-tang in rats. The safety of this tang on acute toxicity was evaluated by single dose toxicity study. Rats were orally administrated in a single dose of 0 and 2000 mg/kg (limited dose) Socheongryong-tang. There were 7 rats in each groups. All animals were sacrificed after 14 days of treatment. After single administration, mortality, clinlcal signs, body weight changes and gross pathological findings were observed for 14 days. Three parameters were tested: organ weight measurement, clinical chemistry, and hematology. In this study with rats, Socheongryong-tang treatment did not show any acute toxicity. No mortality was noted for 14 days of treatment. There were no adverse effects on clinical signs, body weight, organ eight and gross pathological findings at all treatment groups. The clinical chemistry parameters attesting to liver and kidney functions as well as the hematological parameters were within the normal ranges. From single dose toxicity study with rats, it is considered that $LD_{50}$ of Socheongryong-tang is over 2000 mg/kg in oral administration. This finding of the safety on single dose toxicity study of Socheongryong-tang are expected to strengthen the position of Socheongryong-tang as nontoxic medicine.

• 한국자원식물학회:학술대회논문집
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• 한국자원식물학회 2021년도 춘계학술대회
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• pp.59-59
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• 2021

Stachys sieboldii Miq. (SSM) and Acorus gramineus Soland. (AGS) have been used as traditional medicines for thousands of years in parts of Asia, including Korea, China, and Japan. Recent researches on SSM and AGS have documented a wide spectrum of therapeutic properties, including anti-inflammatory, anti-oxidative, neurodegenerative disease effects. However, the toxicity and safety of SSM and AGS, and their mixture (medicinal herber mixture, MHMIX) were not confirmed. Therefore, this study was performed to evaluate the acute toxicity and safety of SSM, AGS and MHMIX. SSM, AGS and MHMIX were orally administered at a dose of 5,000 mg/kg in ICR mice. Animals were monitored for the mortality and changes in the body weight, clinical signs and gross observation during the 14 days after dosing, upon necropsy. We also measured parameters of organ weight, clinical chemistry, and hematology. No dead and no clinical signs were found during the experiment period after administration of a single oral dose of SSM, AGS and MHMIX. There were no adverse effects on clinical signs, body weight, or organ weight and no gross pathological findings in any treatment group. Therefore, LD50 value of SSM, AGS and MHMIX may be over 5,000 mg/kg and it may have no side toxic effect to ICR mice. The results on the single-dose toxicity of SSM, AGS and MHMIX indicate that it is not possible to reach oral dose levels related to death or dose levels with any harmful side effects.

• 한국응용곤충학회지
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• 제47권3호
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• pp.287-292
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• 2008

쯔쯔가무시병을 매개하는 털진드기 유충을 대상으로 유칼립투스 정유, 퍼메스린 그리고 DEET의 기피력과 살비력을 실내에서 여지흡수법을 이용하여 확인하였다. 털진드기 유충에 대한 이들 물질들의 반수치사량($LD_{50}$)은 유칼립투스 정유와 DEET는 각각 0.025와 0.018 $mg/cm^2$로 우수한 살비력을 보였으며, 퍼메스린의 경우는 조사한 최고 농도 수준인 0.2 $mg/cm^2$이상인 것으로 나타났다. 또한 이들 물질을 6.14 $mg/cm^2$으로 처리한 기피력 시험에서 유칼립투스 정유는 100% 기피력을 보였고, 그 처리된 지역에 들어온 개체들은 완전히 벗어나지 못하고 치사하였다. 그러나 퍼메스린의 경우는 가장 높은 시험농도 수준(9.20 $mg/cm^2$)에서도 처리 지역을 통과한 개체들이 생존하였고, 기피력도 60% 정도로 낮게 나타났다. DEET는 1.53 $mg/cm^2$처리 수준에서 퍼메스린에 비해 8.3배, 유칼립투스 정유에 대해서는 2.8배 더 강하게 나타났다. 털진드기 유충에 대한 기피력은 DEET,유칼립투스 정유 그리고 퍼메스린 순이었다. 또 다른 실험에서는 털진드기 유충에 대한 천연 유칼립투스 정유를 유효성분으로 함유한 유제의 살비력이 평가되었다. 60분 간의 노출 시간 동안 1%와 3% 유제는 강한 살비력을 나타내지 못한 반면, 6% 이상의 유제들은 일정 시간이 지나면서 100%의 살비력을 보였다. 이와 같이 털진드기 유충들의 시험 유제들에 대한 반응은 유칼립투스 정유의 함유량 및 노출 시간 모두에 의존적이었다. 이상의 결과로 유칼립투스 정유는 털진드기 유충에 대한 천연 방제제 또는 기피제로서 활용될 수 있는 여지가 높음을 알 수 있었다.