• 방사성폐기물학회지
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• 제13권4호
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• pp.295-300
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• 2015

HPGe 검출기를 이용하여 밀도가 다양한 환경시료에 대한 정밀 분석시 정확한 분석을 위해서는 밀도보정인자가 필요하다. 밀도에 대한 보정인자를 구하기 위해서 본 연구에서는 몬테카를로 코드인 MCNPX 코드를 사용하여 크리스털의 높이, 지름 및 코어의 크기와 같은 특성이 다른 세 대의 p-type HPGe 검출기를 모사하고 밀도 $1g/m^3$의 교정용 표준시료를 이용하여 모델링을 검증하였다. 검증을 통하여 모델링을 확정한 후 0.3, 0.6, 0.9, 1.0, 1.2, $1.5g/m^3$ 밀도를 가진 샘플에 대한 효율을 시뮬레이션하고 밀도보정인자를 도출하였다. 도출된 각 검출기에 대한 밀도보정인자를 비교하였을 때 전 에너지 범위에서 그 차이가 거의 없음을 확인하였으며 이는 검출기의 크리스털과 같은 주요 특성에 대해 밀도보정인자가 독립적임을 의미한다.

• 디지털융복합연구
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• 제13권4호
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• pp.115-125
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• 2015

본 연구의 목적은 융복합 시대에서 지속가능경영활동(사회적 활동, 경제적 활동, 환경적 활동)과 혁신성(관리혁신, 기술혁신)간의 관계를 규명하는 것이다. 이를 위해 다양한 영역에서 시행된 선행연구들을 바탕으로 지속가능 경영활동과 혁신성간의 관계에 대한 모형을 구성하고 기업에 근무하는 종업원들을 대상으로 설문 조사를 실시하였다. 연구모형의 검정은 기술적 분석, 신뢰성 분석, 요인분석, 상관관계분석, 다중회귀분석 등의 통계적 기법을 활용하여 실시되었다. 다중회귀분석 결과, 지속가능경영활동의 세 가지 측면 모두 혁신성에 통계적으로 긍정적인 영향을 미치는 것으로 확인되었다. 즉, 지속가능경영활동의 각 활동들이 적절하게 수행된다면 혁신성을 창출할 수 있다는 것을 알 수 있다. 또한, 실행적인 측면에서 기업의 혁신성을 증대시키기 위해서는 기업 구성원들이 지속가능경영활동을 잘 이해할 수 있는 교육이나 실행전략이 필요할 것이다. 따라서 기업은 지속가능경영활동과 혁신성의 적절한 조화를 이루어 수행해 나감에 따라 지속가능한 기업이 될 것으로 기대된다.

• Journal of Microbiology and Biotechnology
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• 제22권3호
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• pp.378-384
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• 2012

In aquatic invertebrates, particularly marine gastropods, organotin compounds induce irreversible sexual abnormality in females, which is termed imposex, at very low concentrations. Organotin compounds are agonists for nuclear receptors such as RXRs and $PPAR{\gamma}$. However, the imposex phenomenon has not been reported to act as an antagonist on estrogen receptors in other species, including vertebrates and invertebrates. In order to gain insights into the antagonistic activity of organotin compounds on estrogen receptors (ERs), we examined the inhibitive effect of these compounds on estradiol-dependent ${\beta}$-galactosidase activity using the yeast two-hybrid detection system consisting of a combination of the human estrogen receptor ($hER{\beta}$) ligand-binding domain and the co-activator steroid receptor co-activator-1 (SRC1). Tributyltin-hydroxide (TBT-OH) and triphenyltin-chlorine (TPT-Cl) exhibited an inhibitive effect on $E_2$-dependent transcriptional activity, similar to antagonistic chemicals such as 4-hydroxytamoxifen (OHT) or ICI 182,780, at a very low concentration of $10^{-14}$ M TBT or $10^{-10}$ M TPT, respectively. The yeast growth and transcriptional activity with transcriptional factor GAL4 did not exhibit any effect at the tested concentration of TBT or TPT. Moreover, the yeast two-hybrid system using the interaction between p53 and the T antigen of SV40 large did not describe any effect at the tested concentration of OHT or ICI 182,780. However, the interaction between p53 and T antigen was inhibited at a TBT or TPT concentration of $10^{-9}$ M, respectively. These results indicate that TBT and TPT act as inhibitors of ER-dependent reporter gene transcriptional activation and of the interaction between $hER{\beta}$ LBD and the co-activator SRC1 in the yeast two-hybrid system. Consequently, our data could partly explain the occurrence of organotin compound-induced imposex on the endocrine system of mammals, including humans.

• 한국물환경학회지
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• 제34권4호
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• pp.409-422
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• 2018

The purpose of this study is to find the characteristics of organic matters based on the distribution and oxidation rates, as noted according to the spatial and temporal variations from 2008 to 2016. Generally speaking, the Han River system is separated into one lower course and two upper courses which are the Namhan River and Bukhan River. The seasonal factor is one of the most important causes of water quality changing in both of the upper courses as a result of a few pollution sources. The concentration of organic matter was measured as higher in the lower course into which great streams with point and non-point sources were identified. According to seasonal variations, however, the change of the organic matter in the lower course is comparatively slighter than that of organic matters in the upper courses. The oxidation rates related to the BOD were 15 %, 17 % and 26 % in the Bukhan River, Namhan River and the lower course, respectively. These results could be explained that more biodegradable organic matter were seen to have existed in the lower courses comparing to the activity in the upper course. The oxidation rates of the BOD were noted as relatively higher in the eutrophicated places with phytoplankton. Therefore the BOD is one of the good index models to find the characteristic of the eutrophicated water. On the other hand BOD would not be enough to estimate concentration of refractory organic matters in the Bukhan and Namhan river. Consequently, both of the TOC and BOD are necessary indices to understand the identified refractory and/or biodegradable characteristics of organic matter.

• Journal of Forest and Environmental Science
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• 제38권1호
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• pp.55-63
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• 2022

The African swine fever virus (ASFV) remains contagious for a long time, not only in the carcass, but also in the bone marrow of an infected animal. The scavenging activity of various animals on ASFV-infected carcasses is a likely risk factor for ASFV transmission. Thus, we conducted this study to determine whether scavengers are potential vectors for ASFV. In nonprotected wild boar carcasses on the forest floor, we investigated the seasonal patterns of carcass decomposition and scavenger visits for feeding on them. The duration from fresh to early skeletonization (only bones and leather remaining) of adult carcasses was 37.6±23.1 days (n=3, range=11-51 days) in winter. The duration from fresh to later skeletonization (only bones and some fur remaining) of all carcasses, including subadult carcasses, was 8.3±2.5 days (n=4, range=7-12 days) in summer. At all three study sites, leopard cats (30.3%), large-billed crows (21.6%), and golden eagles (18.1%) were the frequently visiting species, representing more than 10% of the total visits (343 visits) in winter, whereas raccoons (21.9%), grey-backed thrushes (39.4%), and eyebrowed thrushes (14.7%) were the most frequent visitors in summer. In winter, crows or cinereous vultures were the first animals to arrive at a carcass; in summer, raccoons or crows arrived first. Our results showed that wild boars, raccoons, and leopard cats relatively frequently visited wild boar carcasses and stayed there for a long time. Wild rodents chewing on or staying near carcasses were photographed during winter. In addition to wild boars, thus, mammals, such as raccoons, leopard cats and rodents, and birds, such as accipitrids and thrushes, may be spreaders of ASFV in South Korea.

• 한국기후변화학회지
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• 제4권1호
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• pp.27-39
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• 2013

본 연구에서는 국내에서 사용되는 무연탄을 국내무연탄, 원료용 수입무연탄, 연료용 수입무연탄으로 분류하여 각각의 발열량 및 온실가스 배출계수를 산정하였다. 본 연구에서 산정된 온실가스 배출계수는 국내무연탄이 $111,477{\pm}4,508kg\;CO_2/TJ$, 원료용 수입무연탄이 $108,358{\pm}4,033kg\;CO_2/TJ$, 연료용 수입무연탄이 $103,927{\pm}8,367kg\;CO_2/TJ$로 산정되었다. 산정된 배출계수를 이용한 온실가스 배출량은 $6,216,942ton\;CO_2$로 무연탄을 상세히 구분하지 않고 산정한 온실가스 배출량보다 12.7% 적게 나타났다. 이에 따라, 무연탄을 상세히 분류하여 활동자료를 수집하는 것이 무연탄의 활동자료를 통합하여 수집하는 것보다 정확한 온실가스 배출량을 산정할 수 있다고 판단된다. 또한, 국내에서 사용되고 있는 무연탄의 경우 IPCC에서 제시하고 있는 무연탄과 특성이 다르기 때문에 국가 온실가스 인벤토리 향상을 위해 무연탄을 용도별로 분류하여 산정해야 한다.

• Advances in environmental research
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• 제9권3호
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• pp.215-232
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• 2020

Crude oils are essential source of energy. It is majorly found in geographical locations beneath the earth's surface and crude oil is the main factor for the economic developments in the world. Natural crude oil contains unrefined petroleum composed of hydrocarbons of various molecular weights and it contains other organic materials like aromatic compounds, sulphur compounds, and many other organic compounds. These hydrocarbons are rapidly getting degraded by biosurfactant producing microorganisms. The present study deals with the isolation, purification, and characterization of biosurfactant producing microorganism from oil-contaminated soil. The ability of the microorganism producing biosurfactant was investigated by well diffusion method, drop collapse test, emulsification test, oil displacement activity, and blue agar plate method. The isolate obtained from the oil contaminated soil was identified as Bacillus subtilis. The identification was done by microscopic examinations and further characterization was done by Biochemical tests and 16SrRNA gene sequencing. Purification of the biosurfactant was performed by simple liquid-liquid extraction, and characterization of extracted biosurfactants was done using Fourier transform infrared spectroscopy (FTIR). The degradation of crude oil upon treatment with the partially purified biosurfactant was analyzed by FTIR spectroscopy and Gas-chromatography mass spectroscopy (GC-MS).

• Toxicological Research
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• 제18권3호
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• pp.215-226
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• 2002

Acute or repeated physical exercise affects a large number of physiological parameters including hemodynamics, respiration, pH, temperature, gastrointestinal function and biotransformation, which determine the pharmacokinetics of drugs and chemicals. The rate and the amount of a chemical reaching the active site are altered by physical exercise, which results in significant changes in pharmacolosical/toxicological activity of the chemical. This aspect of physical exercise has vast implication in therapeutics and in safety evaluation, particularly for chemicals that have a low margin of safety. However there appears to be a wide inter- and intraindividual variation in the effects of physical exercise depend-ing on the duration, intensity and type of exercise, and also on the properties of each chemical. It is suggested that more studies need to be done to determine which factor(s) plays a major role in the disposition of chemicals in human/animals performing physical exercise. Certain chemicals induce severe toxicity due to metabolic conversion to reactive intermediate metabolites. it is suggested that repeated exercise may enhance the free radical scavenging system by increasing the activity of antioxidant enzymes. This area of research remain to be explored to elucidate the interaction of exercise and chemical on the antioxidant system.

• Toxicological Research
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• 제22권1호
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• pp.31-37
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• 2006

It was previously found that melittin inhibited $NF-{\kappa}B$ activity by reacting with signal molecules of $NF-{\kappa}B$ which is critical contributor in cancer cell growth by induction of apoptotic cell death. We here investigated whether melittin inhibits cell growth of human prostate cancer cells through induction of apoptotic cell death, and the possible signal pathways. Melittin ($0{\sim}1\;{\mu}g/ml$) inhibited prostate cancer cell growth in a dose dependent manner. Conversely related to the growth inhibitory effect, melittin increased the induction of apoptotic cell death in a dose dependent manner. Melittin also inhibited DNA binding activity of $NF-{\kappa}B$, an anti-apoptotic transcriptional factor. Consistent with the induction of apoptotic cell death and inhibition of $NF-{\kappa}B$, melittin increased the expression of pro-apoptotic proteins caspase-3, and Bax but down-regulated anti-apoptotic protein Bcl-2. These findings suggest that melittin could inhibit prostate cancer cell growth, and this effect may be related with the induction of apoptotic cell death via inactivation of $NF-{\kappa}B$.

• 한국독성학회:학술대회논문집
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• 한국독성학회 2003년도 춘계학술대회 논문집
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• pp.95.1-95
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• 2003

Ginger (Zingiber officinale Roscoe, Zingiberaceae) has a wide array of pharmacologic effects. Our previous studies have demonstrated that [6]-gingerol, a major pungent ingredient of ginger, inhibits mouse skin tumor promotion and anchorage-independent growth of cultured mouse epidermal cells stimulated with epidermal growth factor. In this study, we have investigated the molecular mechanisms underlying chemopreventive effects of [6]-gingerol on mouse skin carcinogenesis. Cyclooxygenase-2 (COX-2), a key enzyme in the formation of prostaglandins, has been recognized as a molecular target of many chemopreventive as well as anti-inflammatory agents. The murine COX-2 promoter contains several transcriptional elements, particularly those involved in regulating inflammatory processes. One of the essential transcription factors responsible for COX-2 induction is NF-kappa B. Topical application of [6]-gingerol inhibited the COX-2 expression through suppression of NF-kappa B activation in phorbol ester-treated mouse skin. [6]-Gingerol, through down-regulation of p38 MAPK, abrogated the DNA binding activity of NF-kappa B by blocking phosphorylation of p65/RelA at the Ser 536 residue. These findings suggest that [6]-gingerol exerts an anti-tumor promotional activity through inhibition of the p38 MAPK-NF-kappa B siganling cascade in mouse skin.