• 한국산업보건학회지
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• 제6권2호
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• pp.301-312
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• 1996

This study was performed to search a optimal analyzing method of cadmium in whole-blood. Cadmium was determined by graphite furnace atomic absorption spectrometry(GFAAS). We investigated the effect of ashing temperature on the absorbance of cadmium in a simple dilution(ten-fold) method with triton X-100 and matrix modifier methods treated with $NH_4H_2PO_4$(1 and 3%) and $Pd(NO_3)_2$(0.00l and 0.005%) as matrix modifier. We also compared the reported reference values of standard blood with values resulted from optimal analyzing conditions of this study. In case of a simple dilution method, when ashing temperature was set at $450^{\circ}C$, the absorbance of sample and background were $0.334{\pm}0.012$ and $1.382{\pm}0.245$, respectively. Background level was higher than the value(0.8) that can be corrected by $D_2$ background correction method. As ashing temperature was rised to $500^{\circ}C$, the absorbance of sample and background were $0.178{\pm}0.008$ and $0.711{\pm}0.223$ respectively. The higher ashing temperature($450^{\circ}C-650^{\circ}C$) was, the lower the absorbance of sample was. In case of a matrix modifier method with $NH_4H_2PO_4$(1 and 3%), when ashing temperature was rised from $500^{\circ}C$ to $650^{\circ}C$, the absorbance of sample slightly changed. The absorbances of sample at $600^{\circ}C$ were $0.230{\pm}0.017$ and $0.137{\pm}0.012$, respectively. These values were larger than that of simple dilution method. But the absorbance of background was higher than the level that can be corrected by $D_2$ method. In case of a matrix modifier method with $Pd(NO_3)_2$(0.001 and 0.005%), the absorbance of sample and background were higher than those of other methods and were stable and reproducible. When ashing temperature was over $550^{\circ}C$, the absorbance of sample was significantly decreased. In case of 0.005% $Pd(NO_3)_2$ carbon residue remained in graphite tube affected the absorbance of sample and background. From these results, We propose that in case of a simple dilution(ten-fold) method with triton X-100 ashing temperature must be maintained below $400^{\circ}C$. In order to diminish the absorbance of background, the alternative method is attenuation of injection volume or multiplication of dilution ratio. We recommend $Pd(NO_3)_2$ than $NH_4H_2PO_4$ as a matrix modifier. In case of a matrix modifier method with $Pd(NO_3)_2$ ashing temperature might be maintained below $550^{\circ}C$.

• 생명과학회지
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• 제29권2호
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• pp.173-180
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• 2019

Amyloid ${\beta}$-단백질($A{\beta}$)은 알츠하이머 질병의 특징인 노인성 반점의 주요 성분이며 in vivo와 in vitro에서 신경세포를 대상으로 독성효과를 유발한다. 항산화물질과 프로테오글리칸을 포함한 많은 환경인자들에는 $A{\beta}$의 독성을 완화하는 물질들이 존재한다. 특히, 천연물질들 중에서 자신은 독성이 없으며, 알츠하이머 환자에게 치료효능을 나타내는 천연화합물들을 순수 분리하는 것은 매우 가치가 있다. 본 연구에서는 소엽맥문동의 메탄올 추출물로부터 에틸아세테이트 유기용매로 분획한 물질(OJEA)을 대상으로 in vitro상에서 신경세포독성 제어효능을 탐색하였다. 본 실험을 위해 PC12 세포주에 $A{\beta}_{25-35}$로 유발한 독성에 대한 OJEA 분획물의 억제효능을 MTT 환원법 분석으로 측정하였으며, ${\beta}$-secretase 활성에 대한 OJEA 분획물의 억제효능을 세포기반 ${\beta}$-secretase assay system으로 측정하였다. 또한 PC12 세포에서 $A{\beta}_{25-35}$에 의해 유도된 산화적 스트레스에 대한 OJEA 분획물의 억제효과를 지질과산화 분석법으로 수행하였다. 본 연구의 결과는 OJEA 분획물이 PC12 세포에서 $A{\beta}_{25-35}$에 의해 유도된 세포독성을 강하게 예방 또는 억제하는 효과가 있음을 확인하였으며, 또한 ${\beta}$-secretase의 활성을 억제함으로써 $A{\beta}$의 생성을 완화하는 효과를 예상할 수 있었다. OJEA 분획물은 또한 PC12 세포에서 $A{\beta}_{25-35}$에의 노출에 의하여 유도되는 malondialdehyde (MDA)의 생성을 강하게 억제하였다. 결론적으로, 본 연구의 결과에 의하면 OJEA 분획물에는 $A{\beta}$ 독성에 대한 신경세포의 보호효능을 함유하는 생리활성물질이 함유되어 있음을 제시한다.

• 한국해안해양공학회지
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• 제16권4
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• pp.224-232
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• 2004

지난 20여년간 다양한 공사가 시행된 금강하구에서 퇴적으로 인한 수로매몰을 분석하기 위하여 1988년부터 2000년까지 매 2년 간격으로 7가지 경우에 대해 단계별로 수치수동역학모형을 적용한 후측실험이 실시되어 바닥마찰응력의 변화와 상관된 퇴적율 평가가 실시되었다. 금강하구둑 건설로 최대마찰응력장이 약 $1-2N/m^2$ 에서 $0.2-0.6N/m^2$크게 줄어들고, 특히 1994년 금강하구둑의 수문 폐쇄 이후에 장항수로에서는 해저마찰응력이 한계마찰응력으로 제시된 $0.4N/m^2$ 이하로 급감하면서 퇴적환경으로 전이되고 있는 것으로 분석되었다. 하구둑건설은 금강 상류로 전파되는 조석에너지를 차단함으로써 조석수동역학의 급격한 변화를 초래하고 하구둑 전면에 퇴적환경이 급속도로 진행되는 직접적인 원인을 제공하고 있는 것으로 추론되었다. 소형어선의 통행지장을 겪는 장항수로의 매몰평가는 평균대조 조석을 적용하여 분석한 결과 기존에 비해 20% 이상 통행지장을 받는 것으로 평가되었다.

• 접착 및 계면
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• 제17권4호
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• pp.149-154
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• 2016

일반적으로, 화학 물리적 변성이 수반되는 멸균방법을 적용하지 못하는 경우 필터여과에 의한 멸균 방법을 주로 사용한다. 하지만 바이러스의 경우 100 nm의 작은 크기로 인해 박테리아 제거에 사용되는 필터여과에 의한 멸균 방법을 적용하기가 어렵다. 본 논문에서는 화학 물리적 변성 없이 바이러스를 비활성화하는 물질 개발을 위하여, 카테콜기가 도입된 헤파린 고분자(Hep-C)를 합성하였다. Hep-C의 바이러스 비활성화 효과를 알아보기 위해서 표면이 노르에피네프린으로 코팅된 조직배양접시에 아데노연관바이러스(Adeno-associated virus; AAV)를 고정화하였으며, 그 위에 다시 Hep-C를 코팅하여 녹색형광단백질(GFP) 유전자를 전달할 수 있는 AAV의 비활성화 정도를 유세포분석기(FACS)를 이용하여 분석하였다. 그 결과 AAV에 Hep-C를 도포하면 99%에 달하는 비활성화 효과를 보였으며, 헤파린 고분자를 도포한 결과에 비해 강한 염 저항성을 확인할 수 있었다. 이러한 결과로 미루어 보아 제조된 Hep-C는 AAV 바이러스 제거의 효과적 방법으로 충분한 가능성을 가짐을 증명하였다.

• 한국지하수토양환경학회지:지하수토양환경
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• 제18권3호
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• pp.33-51
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• 2013

Spatial and temporal characteristics of nitrate contamination and hydrogeochemical parameters were investigated for springs and surficial and bedrock groundwaters in northeastern part of Hongseong. Two field investigations were conducted at dry and wet seasons in 2011 for 120 sites including measurement of field parameters with chemical analyses of major dissolved constituents. Nitrate concentrations were at background levels in springs while 45% of bedrock groundwater and 49% of surficial groundwater exceeded the drinking water standard of nitrate (10 mg/L as $NO_3$-N). The difference in nitrate concentrations between surficial and bedrock groundwater was statistically insignificant. Cumulative frequency distribution of nitrate concentrations revealed two inflection points of 2 and 16 mg/L as $NO_3$-N. Correlation analysis of hydrogeochemical parameters showed that nitrate had higher correlations with Sr, Mg, Cl, Na, and Ca, in surficial groundwater in both dry and wet season. In contrast, nitrate had much weaker correlations with other hydrogeochemical parameters in bedrock groundwater compared to surficial groundwater and had significant correlations only in wet season. Temporally, nitrate and chloride concentrations decreased and dissolved oxygen (DO) increased from dry season to wet season, which indicates that increased recharge during the wet season affected groundwater quality. Aerobic conditions were predominant for both surficial and bedrock groundwater indicating low natural attenuation potential of nitrate in the aquifers of the study area.

• Journal of Microbiology and Biotechnology
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• 제28권3호
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• pp.357-366
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• 2018

Periodontitis, an infective disease caused by oral pathogens and the intrinsic aging process, results in the destruction of periodontal tissues and the loss of alveolar bone. This study investigated whether Boesenbergia pandurata extract (BPE) standardized with panduratin A exerted anti-periodontitis effects, using an aging model representative of naturally occurring periodontitis. In aged rats, the oral administration of BPE ($200mg{\cdot}kg^{-1}{\cdot}day^{-1}$) for 8 weeks significantly reduced the mRNA and protein expression of $interleukin-1{\beta}$, nuclear factor-kappa B, matrix metalloproteinase (MMP)-2, and MMP-8 in gingival tissues (p < 0.01). In alveolar bone, histological analysis with staining and micro-computed tomography revealed the attenuation of alveolar bone resorption in the BPE-treated aged group, which led to a significant reduction in the mRNA and protein expression of nuclear factor of activated T-cells c1 (NFATc1), c-Fos, tartrate-resistant acid phosphatase, and cathepsin K (p < 0.01). BPE not only increased the expression of osteoblast differentiation markers, such as alkaline phosphate, and collagen type I (COL1A1), but also increased the ratio of osteoprotegerin to RANKL. Collectively, the results strongly suggested that BPE is a natural resource for the prevention or treatment of periodontal diseases.

• Journal of Microbiology and Biotechnology
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• 제17권1호
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• pp.67-73
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• 2007

The present study compared the microbial diversity and activity during the application of various bioremediation processes to crude oil-contaminated soil. Five different treatments, including natural attenuation (NA), biostimulation (BS), biosurfactant addition (BE), bioaugmentation (BA), and a combined treatment (CT) of biostimulation, biosurfactant addition, and bioaugmentation, were used to analyze the degradation rate and microbial communities. After 120 days, the level of remaining hydrocarbons after all the treatments was similar, however, the highest rate (k) of total petroleum hydrocarbon (TPH) degradation was observed with the CT treatment (P<0.05). The total bacterial counts increased during the first 2 weeks with all the treatments, and then remained stable. The bacterial communities and alkane monooxygenase gene fragment, alkB, were compared by denaturing gradient gel electrophoresis (DGGE). The DGGE analyses of the BA and CT treatments, which included Nocardia sp. H17-1, revealed a simple dominant population structure, compared with the other treatments. The Shannon-Weaver diversity index (H') and Simpson dominance index (D), calculated from the DGGE profiles using 16S rDNA, showed considerable qualitative differences in the community structure before and after the bioremediation treatment as well as between treatment conditions.

• 한국농공학회논문집
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• 제57권2호
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• pp.27-36
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• 2015

The objective of this paper was to quantitatively analyze the effect of concentrated animal feeding operations (CAFO) NPS pollution on a small watershed water quality. Monitoring was conducted from March to October, 2013. Monthly flow rate and selected water quality at each monitoring site were measured during dry days. Rainy day monitoring also was conducted. Modeling was conducted to evaluate the effect of CAFO NPS pollution on the water quality at the watershed outlet. The highest and mean concentration of selected water quality indices during rainy days were higher than those in dry days in general. The highest TN concentration measured at the CAFP pollution discharge point was 237.831 mg/L. The results revealed that the CAFO NPS pollution sources could be equally blamed for the water quality degradation of the stream. However, the effect of the NPS pollution from CAFOs seemed not to be very influential to the watershed water quality at the outlet. SWAT modeling revealed that the TN load was reduced by 18.95 %, 23.39 % and 30.53 % at the watershed outlet if the TN load at the CAFO NPS pollution discharge point reduced by 20 %, 40 % and 60 %, respectively. It was thought that the natural attenuation processes played an important role. The modeling was based only on the assumption of the load reduction and not verified by the monitored data. Therefore, it was suggested that a long term monitoring studies for the evaluation of the impact of CAFO NPS pollution on the watershed water quality be conducted.

• Structural Monitoring and Maintenance
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• 제1권1호
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• pp.131-157
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• 2014

Special track systems used to divert a train to other directions or other tracks are generally called 'railway turnout'. A traditional turnout system consists of steel rails, switches, crossings, steel plates, fasteners, screw spikes, timber bearers, ballast and formation. The wheel rail contact over the crossing transfer zone has a dip-like shape and can often cause detrimental impact loads on the railway track and its components. The large impact also emits disturbing noises (either impact or ground-borne noise) to railway neighbors. In a brown-field railway track where an existing aged infrastructure requires renewal or maintenance, some physical constraints and construction complexities may dominate the choice of track forms or certain components. With the difficulty to seek for high-quality timbers with dimensional stability, a methodology to replace aged timber bearers in harsh dynamic environments is to adopt an alternative material that could mimic responses and characteristics of timber in both static and dynamic loading conditions. A critical review has suggested an application of an alternative material called fibre-reinforced foamed urethane (FFU). The full-scale capacity design makes use of its comparable engineering characteristics to timber, high-impact attenuation, high damping property, and a longer service life. A field trial to investigate in-situ behaviours of a turnout grillage system using an alternative material, 'fibre-reinforced foamed urethane (FFU)' bearers, has been carried out at a complex turnout junction under heavy mixed traffics at Hornsby, New South Wales, Australia. The turnout junction was renewed using the FFU bearers altogether with new special track components. Influences of the FFU bearers on track geometry (recorded by track inspection vehicle 'AK Car'), track settlement (based on survey data), track dynamics, and acoustic characteristics have been measured. Operational train pass-by measurements have been analysed to evaluate the effectiveness of the replacement methodology. Comparative studies show that the use of FFU bearers generates higher rail and sleeper accelerations but the damping capacity of the FFU help suppress vibration transferring onto other track components. The survey data analysis suggests a small vertical settlement and negligible lateral movement of the turnout system. The static and dynamic behaviours of FFU bearers appear to equate that of natural timber but its service life is superior.

• 한국해안해양공학회지
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• 제18권2호
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• pp.154-165
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• 2006

본 연구에서는 수중 천퇴부에서 쇄파가 발생할 시 주변 파랑과 파랑류의 평형계를 직접 해석할 수 있는 Boussinesq 방정식 모델을 수립하고 이 결과를 수리실험 결과와 비교하였다. 사용된 쇄파모델은 쇄파 감쇠항을 모멘텀 방정식에 포함시키는 일종의 와점성 계수 모델이며, 관련된 쇄파 매개변수의 적정 값들을 Vincent and Briggs (1989)의 규칙파 실험자료를 이용한 민감도 분석을 통하여 결정하였다. 구해진 적정 매개변수 값들을 가지고 수치해석을 수행하여 이 결과를 불규칙파 실험결과와 이어도 천연암초의 수리모형실험 결과와 비교하였다. 그 결과, 천퇴부 하류 쪽에 파 진행방향으로 향하는 강한 쇄파유도류가 발생함에 따라 저파고대가 형성되며 전반적으로 계측파고의 분포와 유사함을 확인하였다.