• Toxicological Research
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• 제25권3호
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• pp.113-118
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• 2009

Cell death induced by menadione (vitamin K-3,2-methyl-1,4-naphthoquinone) has been investigated in human promyelocytic leukemia HL-60 cells. Menadione was found to induce both apoptosis and necrosis in HL-60 cells. Low concentration ($1{\sim}$50 ${\mu}$M) of menadione induced apoptotic cell death, which was demonstrated by typical DNA ladder patterns on agarose gel electrophoresis and flow cytometry analysis. In contrast, a high concentration of menadione (100 ${\mu}$M) induced necrotic cell death, which was demonstrated by DNA smear pattern in agarose gel electrophoresis. Necrotic cell death was accompanied with a great reduction of cell viability. Menadione activated caspase-3, as evidenced by both increased protease activity and proteolytic cleavage of 116 kDa poly(ADP-ribose) polymerase (PARP) into 85 kDa cleavage product. Caspase-3 activity was maximum at 50 ${\mu}$M of menadione, and very low at 100 ${\mu}$M of menadione. Taken together, our results showed that menadione induced mixed types of cell death, apoptosis at low concentrations and necrosis at high concentrations in HL-60 cells.

• Ocean and Polar Research
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• 제27권1호
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• pp.45-58
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• 2005

Temperature, salinity, dissolved oxygen, COD, dissolved inorganic nitrogen(DIN), dissolved inorganic phosphorus (DIP), and chlorophyll were measured in the surface and bottom waters of Cheonsu Bay in April, August, December 2003, and Hay 2004. DIN showed a large seasonal variation, with higher values in summer and lower in spring. The significant decrease in DIN concentration was observed from April to May, which may imply the occurrence of spring phytoplankton bloom sometime in these periods. In contrast, DIP did not show distinct seasonal variation, with relatively low values compared with other coastal regions. The low DIP concentration in Cheonsu Bay is ascribed to a limited phosphorus input around Cheonsu Bay. The Nf ratios of Cheonsu Bay much higher than the Redfield ratio(16) in all season indicate that phytoplankton growth is limited by phosphorus. Based on low chlorophyll concentrations and eutrophication index, Cheonsu Bay has not been in eutrophic condition during our observation periods. In the artificial lakes located around Cheonsu Bay, however, chlorophyll concentrations were very high, mostly over $10{\mu}g\;l^{-1}$, indicating that they are now in severe eutrophic condition.

• 한국환경과학회지
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• 제27권6호
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• pp.349-358
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• 2018

In this study, using coke dust from ironwork, the pulse pressure on a pulse air jet bag filter was investigated considering the influence of the pressure loss due to filtration velocity and pressure intervals. The research on the optimal pulse pressure prediction of a pulse air jet type bag filter using coke dust showed the following results. Pressure loss volatility produced by the pulse pressure under low dust concentration(0.5, $1g/m^3$) and low face velocity(1.25 m/min) was less than $10mmH_2O$. This suggests that the pulse pressure has a low impact on the pressure loss. In contrast, pressure loss volatility under high dust concentration($3g/m^3$) and high face velocity(1.75 m/min) was $25mmH_2O$. Therefore, pulse pressure with high dust concentration and high face velocity has a strong influence on the pressure loss volatility, compared to the condition of low dust concentration and low face velocity. The optimal pulse pressure of inlet dust concentration($0.5g/m^3$) was $6kg/cm^2$ under the same face velocity(1.75 m/min). As concentration increased from 1 to $2g/m^3$, the pulse pressure gradually reached $5kg/cm^2$ thus indicating that the pulse pressure($5kg/cm^2$) is pertinent at a high concentration($3g/m^3$). The pulse intervals: 20, 25 and 30 sec, which are relatively longer than 10 and 15 sec, corresponded to high pressure loss volatility produced by the pulse pressure. Furthermore, low pressure loss volatility was noted at $5kg/cm^2$ of the overall pulse pressure.

• 한국환경생태학회지
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• 제34권5호
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• pp.466-482
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• 2020

본 연구는 도로에서 발생하는 미세먼지 농도가 도시 개발 형태에 따라 인접 생활권별로 어떻게 확산되는지 시뮬레이션을 통해 파악하고자 하였다. 연구는 경상남도 밀양시청 앞 6차선 도로를 중심으로 한 도로영향권 시가지를 대상으로 진행하였다. 시뮬레이션 프로그램인 ENVI-met 모델을 가로녹지 유무, 도로변 건축물의 높이에 따라 변수를 조정하여 미세먼지 농도의 확산정도를 파악하였다. 모델링 결과 도로변 건물이 고층으로 형성되어 있고 가로녹지가 조성되어 있는 경우 인접 생활권으로 확산된 미세먼지 농도가 가장 낮았으며, 다음으로는 고층건물군에 가로녹지가 없는 상태의 농도가 낮았다. 반면 저층건물군이 형성된 경우에는 가로녹지 유무에 관계없이 인접생활권으로 확산된 미세먼지 농도는 높게 나타났다. 고층건물의 경우 빌딩풍에 의해 건축물 주변으로 강한 바람이 형성되는 만큼 바람에 의해 미세먼지가 빠르게 외부로 확산되어 농도가 낮아지는 것으로 확인할 수 있었다. 반면 가로녹지 조성이 도로변 생활권에 미치는 미세먼지 저감효과는 뚜렷하지 않았다. 특히 도로변 건축물이 저층일 경우 가로녹지를 조성과 생활권미세먼지농도변화와 관련성은 없는 것으로 확인되었다. 본 연구는 미세먼지가 도로에서만 발생하는 것을 가정하여 모델링을 진행한 것으로 향후 다양한 변수에 따른 미세먼지 확산모형 연구 및 현장연구의 보완을 필요로 하였다.

• 한국환경보건학회:학술대회논문집
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• 한국환경보건학회 2005년도 국제학술대회
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• pp.399-405
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• 2005

In this study, we investigated the gas chromatography (GC) and pulsed flame photometric detection (PFPD) system for the analysis of four major reduced S compounds including hydrogen sulfide ($H_2S)$; methyl mercaptan ($CH_3SH$); dimethyl sulfide (DMS); and dimethyl disulfide(DMDS) contained in environmental samples. To analyze these compounds in high concentration range (above ppb level), we developed a high mode analytical setting with the loop-injection system. By contrast, we also established a low mode setting for the analysis of low concentration samples (ppt-level samples from ambient air) by the combination with thermal desorption unit(TDU). Comparative analysis of both settings revealed that relative detection properties of four S compounds are systematic enough. The results of high mode analysis indicated that the patterns were systematic among compounds: H2S exhibited the lowest sensitivity, while DMBS showed the strongest one. The results were also compared in terms of sensitivity reductions for all compounds by dividing slope ratios between low and high mode system. Although low mode system exhibited significant reductions on the order of a few tens times, their detection characteristics were highly consistent as it was shown in the high mode setting. To learn more about absolute and relative relations between two different modes of S analysis, future studies may have to be directed to cover more complicated nature of GC/PFPD performance. Hydrogen sulfide($H_2S$) was over in summer about low level of olfactory sense 410 ppt, Methyl mercaptan(C$H_3SH$) was over in apring and summer about low level of olfactory sense 70, Dimethyl sulfide(DMS) was not over in four season about low level of olfactory sense 2,200 ppt. Carbon disulfide($CS_2$) was not over in four deason about Tow level of olfactory sense 210,000, Dimethyl disulfide(DMDS) was not over in summer about low level of olfactory sense2,000.

• 한국방사선학회논문지
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• 제14권5호
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• pp.603-612
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• 2020

본 연구의 목적은 하지 혈관조영검사에서 매개변수인 관전류 (mA)와 SOD에 대한 조영제 농도(300, 320, 350) 희석률의 관계가 화질에 미치는 영향을 알아보는 데 있다. 이를 위해 말초혈관 직경 크기로 자체 제작한 3 mm 혈관모형 Water 팬텀을 이용하여, 관전류 (mA), SOD 변화와 조영제 농도(300, 320, 350) 희석률 변화의 관계를 SNR 값과 CNR 값으로 측정하고 변동계수를 (cv < 10) 분석하였다. SNR 값과 CNR 값의 측정에 사용된 소프트웨어는 Image J 1.50i, (NIH) National Institutes of Health, USA)로, PACS에 전송된 의료영상표준(DICOM, digital imaging and communications in medicine) 3.0 파일에서 팬텀에 대한 관심영역(ROI, region of interest)과 배경(Background)의 영상 신호를 수치적으로 확인한 후 평균 신호값(MPV, mean pixel value)과 표준편차(SD, standard deviation)를 이용하였다. 관전류 변화에 대한 조영제 농도별 희석률에서 관전류 (146 mA)과 관전류 (102 mA)의 SNR과 CNR 비교결과, SNR과 CNR 모두 CM : N/S 희석률 (100% ~ 30% : 70%) 구간까지 변동계수 값이 10 이하로 작게 나타났으나, CM : N/S 희석률 (20% : 80%~ 10% : 90%) 구간에서는 변동계수 값이 10 이상으로 나타났다. SOD 변화에 대한 조영제 농도별 희석률에서 SOD (32.5 cm)과 SOD (22.5cm)의 SNR과 CNR 비교 결과, SNR과 CNR 모두 CM : N/S 희석률 (100% ~ 30% : 70%) 구간까지 변동계수 값이 10 이하로 작게 나타났으나, CM : N/S 희석률 (20% : 80%~ 10% : 90%) 구간에서는 변동계수 값이 10 이상으로 나타났다. SOD 변화에 대한 조영제 농도별 희석률에서 SOD (32.5 cm)과 SOD (12.5cm)의 SNR과 CNR 비교 결과, SNR과 CNR 모두 CM : N/S 희석률 (100% ~ 30% : 70%) 구간까지 변동계수 값이 10 이하로 작게 나타났다. 그러나 CM : N/S 희석률 (20% : 80%~ 10% : 90%) 구간에서는 변동계수 값이 10 이상으로 나타났다. 결과적으로 인터벤션에서 하지 말초혈관조영술을 포함한 다른 검사나 시술에서 낮은 관전류 값을 설정하고, 테이블은 영상수상기에 최대한 가깝게 하여, 조영제 농도(300)을 CM : N/S 희석률 (30% : 70%)로 사용하는 것이 신장에 대한 부담과 피폭에 대한 부담을 동시에 줄이면서 적정 농도의 영상을 얻을 수 있는 가장 효율적인 방법으로 제시한다.

• 한국축산식품학회지
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• 제31권4호
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• pp.543-550
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• 2011

Various concentrations of whey protein isolate (WPI), such as 0.1, 0.5, 1.0, 2.5, and 5.0%(w/v), containing 1.0%(w/v) eugenol were prepared by high speed homogenization to formulate nanoemulsions (NEs) and to investigate their antimicrobial activity. The results showed that particle size decreased according to increases in WPI concentration. Similarly, the ${\zeta}$-potential value was reduced to a negative charge when using WPI concentrations >0.1%(w/v). In contrast, no significant differences in particle size were observed during 1 mon of storage, except for the 0.1%(w/v) WPI NE. The ${\zeta}$-potential value depended on the increase in WPI concentration and storage duration, except for NE1 and NE5, suggesting that a low or high concentration of emulsifier was not effective for maintaining the droplet form of the eugenol NE. The results of an antibacterial effect investigation indicated that the growth of Escherichia coli was inhibited based on an increase in eugenol concentration in all NE formulations. Moreover, a membrane permeability study showed that total leakage content increased according to incubation time.

• 한국초지조사료학회지
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• 제20권3호
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• pp.193-198
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• 2000

Plant characteristics of four winter crop hairy vetch, red clover, crimson clover and rye as green manure were evaluated at three harvesting time(Apri1 23, May 9, May 28) in spring to select superior winter green manure crop. Rye and hairy vetch had superior wintering ability and produced high dry matter compared with crimson clover and red clover. But N amount of rye was small because of its low plant N% despite of early dry matter accumulation. Wintering ability of crimson clover was very poor, so its dry matter decreased rapidly with low seeding rate. Hairy vetch had high N % (4%, C:N ratio 11) and produced high N yield among four plant. It is estimated that hairy vetch have high N-fixing ability because its N% was not changed largely despite of dry matter accumulation at late harvesting time contrast to the other legume. It was thought that hairy vetch was superior green manure crop in considering yield of dry matter and N. (Key words : Winter legumes, Hairy vetch, Green manure yield, Nitrogen concentration)

• 한국세라믹학회지
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• 제44권9호
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• pp.465-470
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• 2007

This paper presents an experimental study of the sulfate resistance of mortars and pastes exposed to sodium sulfate solutions up to one year. In order to check deterioration modes due to sulfate attack, the sodium sulfate solution was varied at three concentration steps (3,380, 10,140 and 33,800 ppm of $SO_4^{2-}$ ions), and maintained at ambient temperature. The tests include a visual examination, expansion and compressive strength loss measurements as well as x-ray diffraction tests. The experimental data indicated that the use of cement with a low $C_3A$ content and low silicate ratio has a beneficial effect on the sulfate attack of mortars. In contrast, the mortars with a high $C_3A$ content and high silicate ratio became severely degraded due to the formation of ettringite, gypsum and/or thaumasite in the cement matrix.

• 한국광물학회지
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• 제28권2호
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• pp.165-171
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• 2015

부산과 울산의 중심지역에 대해 공기 중의 분진시료를 채취하여, 위상차현미경, 위상차분산현미경, 주사전자현미경 등으로 석면을 분석한 결과, 석면은 검출한계 이하로서 확인되지 않았다. 공기중의 분진시료에는 섬유상물질이 다수 포함되었으나, 이들은 대부분 유기질 섬유인 것으로 나타났다. 무기질 섬유물질로는 암면, 세라믹섬유, 석고 등이 소량 포함되었으며, 비섬유상인 석영, 방해석, 장석등의 광물도 가끔 관찰되었다. 국내의 공기 중 분진의 석면분석은 주로 위상차현미경으로 관찰하는 것으로 규정되어 있으나, 이것만으로는 석면의 식별이 불가능한 것으로 나타났다. 따라서 일본 JIS법과 같이 저온회화 처리 장치에 의한 유기물질 제거 후에 분산염색법으로 석면을 식별하고 계수하는 것이 효율적인 것으로 사료된다.