• Molecular & Cellular Toxicology
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• 제5권3호
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• pp.179-186
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• 2009

Hexachlorobenzene (HCB) is a bioaccumulative, persistent, and toxic pollutant. HCB is one of the 12 priority of Persistent Organic Pollutants (POPs) intended for global action by the United Nations Environment Program (UNEP) Governing Council. POPs are organic compounds that are resistant to environmental degradation through chemical, biological, and photolytic processes. Some of HCB is ubiquitous in air, water, soil, and biological matrices, as well as in major environmental compartments. HCB has effects on various organs such as thyroid, bone, skin, kidneys and blood cells and especially, revealed strong toxicity to liver. In this study, we identified genes related to hepatotoxiciy induced by HCB in human hepatocellular carcinoma (HepG2) cells using microarray and gene ontology (GO) analysis. Through microarray analysis, we identified 96 up- and 617 down-regulated genes changed by more than 1.5-fold by HCB. And after GO analysis, we determined several key pathways which known as related to hepatotoxicity such as metabolism of xenobiotics by cytochrome P450, complement and coagulation cascades, and tight junction. Thus, our present study suggests that genes expressed by HCB may provide a clue for hepatotoxic mechanism of HCB and gene expression profiling by toxicogenomic analysis also affords promising opportunities to reveal potential new mechanistic markers of toxicity.

• Asian-Australasian Journal of Animal Sciences
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• 제17권4호
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• pp.564-568
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• 2004

Restructuring had made it possible to utilize lower value cuts and meat trimmings from spent animals by providing convenience in product preparation besides enhancing tenderness, palatability and value. Milk co-precipitates (MCP) have been reported to improve the nutritional and functional properties of certain meat products. This study was undertaken to evaluate the influence of incorporation of milk co-precipitates at four different levels viz. 0, 10, 15 and 20% on the quality of restructured buffalo meat blocks. Low-calcium milk co-precipitates were prepared from skim milk by heat and salt coagulation of milk proteins. Meat chunks were mixed with the curing ingredients and chilled water in a Hobart mixer for 5 minutes, followed by addition of milk co-precipitates along with condiments and spice mix and again mixed for 5 minutes. Treated chunks were stuffed in aluminium moulds and cooked in steam without pressure for 1.5 h. After cooking, treated meat blocks were compared for different physico-chemical and sensory attributes. Meat blocks incorporated with 10% MCP were significantly better (p<0.05) than those incorporated with 0, 15 and 20% MCP in cooking yield, percent shrinkage and moisture retention. Sensory scores were also marginally higher for meat blocks incorporated with 10% MCP than product incorporated with 15 and 20% MCP, besides being significantly higher than control. On the basis of above results 10% MCP was considered optimum for the preparation of restructured buffalo meat blocks. Instrumental texture profile analysis revealed that meat blocks incorporated with 10% MCP were significantly better (p<0.05) in hardness/ firmness than control although, no significant (p>0.05) differences were observed in cohesiveness, springiness, gumminess and chewiness of both type of samples.

• 한국물환경학회지
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• 제21권2호
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• pp.118-124
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• 2005

The oxygen solubilized device(O.S.D) and standardized microorganism culture system is more efficient than physical and chemical purification techniques in closed water. This study was to determine how the O.S.D and standardized culture system is efficient in purification capacity in closed water based on the lab scale and pilot plant. In the batch test, inducing the quantitative results from pilot plant operation condition, removal efficiency of COD and TN were about 48.3% and 35% respectively, while SS and chlorophyll-a were 94.9% and 68.7%. The pilot plant results showed that suspended solid(SS) and chlorophyll-a removal efficiency were 60% and 59% respectively, due to coagulation characteristics by standardized culture. Total nitrogen(TN) and total phosphorus(TP)showed good effect for the purification of target pond water quality from field data. Additionally, released velocity was determined in control condition of $5.31mgPO{_4}^{3-}{\cdot}m^{-2}{\cdot}day^{-1}$ and $2486.8mgCOD{\cdot}m^{-2}{\cdot}day^{-1}$. Otherwise, phosphate and COD reflux in the aeration and microorganism condition was showed $-9.95mgPO{_4}^{3-}{\cdot}m^{-2}{\cdot}day^{-1}$ and $-397.88mgCOD{\cdot}m^{-2}{\cdot}day^{-1}$. This technology is the most effective not only removal of SS and chlorophyll-a but also control of phosphate and COD release which is very important phenomena in evaluating water quality in closed water like a reservoir and pond.

• 상하수도학회지
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• 제24권5호
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• pp.527-536
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• 2010

Although the bubble-floc agglomerate floated and formed the float layer on the surface of the water in the DAF process, after inducing in the thickening tank a part of the bubble-floc agglomerate come up again to the surface and the other is settled at the bottom of the tank. The bubble-floc agglomerate divided into two group as the scum on the surface and the sludge of the bottom gives rise to operational troubles for the thickening process. In order to find out the cause of break-up and the effective thickening method for sludge from the DAF process, the composition of the bubble-floc agglomerate was investigated and a series of flotation experiments carried out. There was no difference of composition between the scum on the surface and the sludge of the bottom in the thickening tank. The coagulation was not effective to improve the trouble that the bubble-floc agglomerate divided into the scum and the sludge. It was estimated that for the bubble-floc agglomerate of thickening tank the trouble was caused by not the change or the difference of chemical composition but whether the bubble-floc agglomerate hold bubbles. Furthermore, for the effective thickening of sludge from the DAF process, it is required an additional flotation applied the AS ratio depending upon the solid concentration of sludge as the operation parameter.

• 제어로봇시스템학회논문지
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• 제3권6호
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• pp.644-651
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• 1997

In the water purification plant, chemicals are injected for quick purification of raw water. It is clear that the amount of chemicals intrinsically depends on water quality such as turbidity, temperature, pH and alkalinity. However, the process of chemical reaction to improve water quality (e.g., turbidity) by chemicals is not yet fully clarified nor quantified. The feedback signal in the process of coagulant dosage, which should be measured (through the sensor of the plant) to compute the appropriate amount of chemicals, is also not available. Most traditional methods focus on judging the conditions of purifying reaction and determine the amounts of chemicals through manual operation of field experts using Jar-test data. In this paper, a systematic control strategy is proposed to derive the optimum dosage of coagulant, PAC(Polymerized Aluminium Chloride), using Jar-test results. A neural network model is developed for coagulant dosing and purifying process by means of six input variables (turbidity, temperature, pH, alkalinity of raw water, PAC feed rate, turbidity in flocculation) and one output variable, while considering the relationships to the reaction of coagulation and flocculation. The model is utilized to derive the optimum coagulant dosage (in the sense of minimizing turbidity of water in flocculator). The ability of the proposed control scheme validated through the field test has proved to be of considerable practical value.

• 대한화장품학회지
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• 제21권1호
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• pp.67-83
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• 1995

생체내 피부 자극은 일련의 복합적인 생리 화학적 변화를 수반한다. 이러한 생체내 현상을 보다 민감하게 반영하고, 동물 시험 경감 측면 및 정확성, 재현성을 보완하기 위하여 자극 물질 검색을 위한 대체 시험법이 필요하게 되었다. CAMVA는 이러한 필요성에 의해 고안된 방법의 하나로써 약 10일된 유정란의 복합적인 혈관이 융합된 장뇨막내에 자극 물질을 투여하고 일정 시간 후, 막 내 혈관의 충혈, 출혈, 응집현상 등의 변화를 통해 자극 정도를 평가하는 in vitro 시험계이다. 본 연구에서는 화장품 영역에서 중요한 위치를 차지하는 계면활성제의 자극 정도를 검색하여 in vitro 시험법인 CAMVA와 in vivo 시험법간의 상관성을 조사하였으며, 그 결과 매우 높은 상관성을 나타냄을 알 수 있었다. 그러므로 CAMVA는 안 자극 시험의 대체 시험법 뿐만 아니라 피부자극의 예측에도 적용 가능한 유용한 시험법이라 생각된다.

• 한국지반환경공학회 논문집
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• 제2권1호
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• pp.67-79
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• 2001

본 연구는 최근 개발된 마이크로 복합실리카 그라우트재의 공학적 특성을 규명한 것으로서 연구에 사용된 그라우트재는 MSG-N(완결형)을 주로 사용하였으며, 화학성분, 입도분포, 광물특성을 분석하고 응결재인 특수규산과 보통시멘트에 대한 특성도 비교 분석하였다. 공학적 특성을 파악하기 위하여 블리딩시험, 전도시험, 응결시험, 육안관측, SEM촬영, 일축압축강도시험과 매립지에 대한 현장적용성 시험 등을 심사하였다. 이상과 같은 일련의 시험들에 의한 결과 일반적인 소디움 실리케이트 그라우트보다 마이크로 복합실리카 그라우트 공법(MSG공법)이 강도적인 측면에서는 2배정도 우수하고, 알카리 용출량이 현저하게 저하되었다. 특히 MSG공법에 의한 현장적용성 평가에 있어서 매립장 침출수 차단공법으로써 침투성이 우수하고 충분한 약액의 주입에 의해 상당한 투수계수 저감효과가 있음을 알 수 있었다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2003년도 춘계학술대회 논문집 센서 박막재료 반도체 세라믹
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• pp.166-169
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• 2003

In this study, we evaluated the characteristics by the addition of 3 different kinds of nonionic surfactant to improve the dispersion stability of slurries. Slurry stability is an issue in any industry in which settling of particles can result in poor performance. So we observed the variation of particle size and settling rate when the concentration and addition time of surfactant are changed. When the surfactant is added after milling process, the particle size and pH became low. It is supposed that the particle agglomeration was disturbed by adsorption of surfactant on alumina abrasive. The settling rate was relatively stable when nonionic surfactant is added about 0.1~1.0 wt%. When molecular weight(MW) is too small like Brij 35, it was appeared low effect on dispersion stability. Because it can't prevent coagulation and subsequent settling with too small MW. The proper quality of MW for slurry stability was presented about 500,000. Consequently, the addition of nonionic surfactant to alumina slurry has been shown to have very good effect on slurry stabilization. If we apply this results to copper CMP process, it is thought that we will be able to obtain better yield.

• Journal of Dairy Science and Biotechnology
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• 제35권4호
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• pp.270-285
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• 2017

Among milk proteins, caseins are not subjected to chemical changes during heat treatment of milk; however, whey proteins are partially denatured following heat treatment. The degree of whey protein denaturation by heat treatment is decreased in the order of high temperature short time (HTST) > low temperature long time (LTLT) > direct-ultra-high temperature (UHT) > indirect-UHT. As a result of heat treatment, several changes, including variations in milk nitrogen, interactions between beta-lactoglobulin and k-casein, variations in calcium sulfate and casein micelle size, and delay of milk coagulation by chymosin action, were observed. Lysine, an important essential amino acid found in milk, was partially inactivated during heat treatment. Therefore, the available amount of lysine decreased slightly (1~4% decrease) after heat treatment, However, the influence of heat treatment on the nutritional value of milk was negligible. Nutritional value and nitrogen balance did not differ significantly between UHT and LTLT in milk. In conclusion, our results showed that heat treatment of milk did not alter protein quality. Whey proteins denatured to a limited extent during the heat treatment process, and the nutritional value and protein quality were unaffected by heat treatment.

• 한국건축시공학회지
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• 제10권2호
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• pp.59-66
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• 2010

본 연구에서는 흡착 및 내열, 내화성이 우수한 카본블랙을 이용하여, 콘크리트의 제반성능을 파악하여, 콘크리트용 혼화재료로써 활용가능성 여부를 판단하고자 함이 본 연구의 목적이다. 실험결과 굳지 않은 콘크리트에서는 흡수율 및 미립분의 카본블랙의 충전효과로 인하여 슬럼프증가 및 공기량 감소를 나타내었으며, 블리딩, 관입저항에 의한 응결시간은 양호한 결과로 나타났다. 또한 경화콘크리트의 강도 특성에는 Plain보다 높은 강도를 나타내었으며, 포졸란 반응에 의해 장기강도로 갈수록 강도발현이 높게 나타났다. 또한 약 $850^{\circ}C$내외의 가열 후의 압축강도에서 치환율이 증가할수록 내화, 내열성이 높게 나타났으며, 건조수축 역시 양호하게 나타났고, CO, $CO_2$, 포름알데히드의 환경성 평가도 Plain보다 양호한 결과로 나타났다. 이상 결과를 종합하면, 고강도의 배합설계를 고려한 적절한 AE감수제를 사용할 경우 카본블랙이 콘크리트용 혼화재로써 사용이 가능할 것으로 판단된다.