• 한국환경보건학회:학술대회논문집
• /
• 한국환경보건학회 2005년도 Proceedings of KSEH.Minamata Forum
• /
• pp.103-114
• /
• 2005

Chlorine disinfection has been used in drinking water supply to disinfect the water-borne microbial disease which may cause to serious human disease. As Chlorination is still the least costly, relatively easy to use, chlorination is the primary means to disinfect portable water supplies and control bacterial growth in the distribution system. However, chlorine also reacts with natural organic matter (NOM), which presents in nearly all water sources, and then produces disinfection by-product (DBps), which may have adverse health effects. Although the existent DBPs have been reported in drinking water supplies, it is not feasible to predict the levels of the various DBPs due to the complex chemistry reaction involved. The objectives of this study were to investigate seasonal variation of DBPs formation and difference of DBPs concentration in the plant to tap water. The average concentration of THMs was 20.04 ${\mu}g/{\ell}$, HAAs 8-15 ${\mu}g/{\ell}$, HANs 2-4.5 ${\mu}g/{\ell}$ respectively. Distant variation of DBPs formation is that THMs concentration increase by 17% at 2 km point from the plant and by 28% at 7 km and HAAs, HANs also increase each by 16%, 32%, at 2 km from the plant and 35%, 56%, at 7 km. DBPs increase in water supply pipe continually. The seasonal occurrence of DBPs is that in May and August DBPs concentration is very high then in March, in May DBPs concentration is highest. The temperature is main factor of DBPs formation, precursor also. Precursor which was accumulated for winter flowed into the raw water by flooding in spring and summer and produced DBPs. Therefore for the supply of secure drinking water, it is required to protect precursor of flowing into raw water and to add to BCAA and DBAA to drinking water standards.

• Journal of Microbiology and Biotechnology
• /
• 제31권7호
• /
• pp.999-1010
• /
• 2021

Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous in the environment. They are highly toxigenic and carcinogenic. Probiotic bacteria isolated from fermented foods were tested to check their ability to degrade and/or detoxify PAHs. Five probiotic bacteria with distinct morphologies were isolated from a mixture of 26 fermented foods co-cultured with benzo(a)pyrene (BaP) containing Bushnell Haas minimal broth. Among them, B. velezensis (PMC10) significantly reduced the abundance of BaP in the broth. PMC10 completely degraded BaP presented at a lower concentration in broth culture. B. velezensis also showed a clear zone of degradation on a BaP-coated Bushnell Haas agar plate. Gene expression profiling showed significant increases of PAH ring-hydroxylating dioxygenases and 4-hydroxybenzoate 3-monooxygenase genes in B. velezensis in response to BaP treatment. In addtion, both live and heat-killed B. velezensis removed BaP and naphthalene (Nap) from phosphate buffer solution. Live B. velezensis did not show any cytotoxicity to macrophage or human dermal fibroblast cells. Live-cell and cell-free supernatant of B. velezensis showed potential anti-inflammatory effects. Cell-free supernatant and extract of B. velezensis also showed free radical scavenging effects. These results highlight the prospective ability of B. velezensis to biodegrade and remove toxic PAHs from the human body and suggest that the biodegradation of BaP might be regulated by ring-hydroxylating dioxygenase-initiated metabolic pathway.

• Childhood Kidney Diseases
• /
• 제3권2호
• /
• pp.153-160
• /
• 1999

목적 : 소아 IgA 신병증을 Haas에 의한 조직 병리학적 분류로 분류하고 이들의 임상 소견과 수년간의 추적 관찰을 통하여 임상 경과, 신기능저하의 빈도 및 위험인자를 알아보고자 본 조사를 시행하였다. 방법 : 대상 환아는 과거 11년간 경북대학교병원 소아과에 입원하여 신생검 소견상 IgA 신병증으로 진단된 60례로 하였으며 이들을 Haas의 subclass로 분류하고 임상 소견과 각종 검사실 성적을 비교 관찰하였고 또한 3-4년간의 추적 관찰을 통하여 각 subclass의 임상 경과, 신기능저하의 빈도 등을 알아보았다. 결과 : Haas의 조직학적 분류에 의한 subclass는 I 10례, III 36례, IV 12례, V 2례였으며 subclass II는 한 례도 없었다. 성별 분포는 남아 45례 여아 15례로 남아에 호발하였으며 (남 : 여 = 3 : 1) 평균 발병 연령은 $10.4{\pm}2.8$세로서 subclass에 따른 차이는 없었다. 육안적 혈뇨가 71.7%를 차지하였으며 진단 당시 고혈압이 2례, 질소혈증이 3례에서 관찰되었다. 혈청 단백과 알부민치는 subclass IV 및 V에서 각각 $6.3{\pm}1.1,\;3.3{\pm}0.9$ 및 $4.5{\pm}1.1,\;2.1{\pm}0.3g/dL$로서 subclass가 증가함에 따라 감소하였으며 24시간 뇨단백 배설양 ($mg/m^2/day$)은 subclass가 증가함에 따라 배설양도 증가하여 subclass IV는 $1338{\pm}1031$, subclass V는 $4500{\pm}1500$의 심한 단백뇨를 보여주었다. 혈청 IgA치는 28.3%에서 증가되어 있었으며 subclass의 정도 및 환아의 임상 경과와는 무관하였다. 추적 관찰 기간중 첫 1-2년에 14%, 3-4년에는 37.1%에서 정상 뇨소견(혈뇨의 소실)이 관찰되었으며 subclass에 따른 차이는 없었다. 점진적인 신기능 저하를 보인 경우는 3례로서 이들은 Haas의 subclass III, IV 및 V가 각각 1례씩이였다. 결론 : 소아에서의 IgA신병증의 예후는 지금까지 알려져 온 것보다 만성 신부전으로의 진행이 높은 것으로 생각되며 Haas의 조직학적 분류가 예후 판정에 도움이 된다고 생각한다. 그러나 본 연구는 대상 환아 및 추적 관찰 기간이 짧았기 때문에, 앞으로는 다 기관 공동 연구에 의하여 더 많은 예 수와 10년 이상의 장기 추적관찰에 의한 광범위한 연구가 이루어져야 할 것으로 생각한다.

• 한국진공학회지
• /
• 제8권2호
• /
• pp.148-152
• /
• 1999

the low temperature magnetoresistance effect, electron mobilities, and 2 Dimensional electron Gases (2DEG) properties were investigated in $Si/Si_{1-x}Ge_x$ quantum well devices. N-type $Si/Si_{1-x}Ge_x$ structures were fabricated by utilizing a gas source Molecular Beam Epitaxy (GSMBE). Thermal oxidation was carried out in a dry O atmosphere at $700^{\circ}C$ for 7 hours. Electron mobilities were measured by using a Hall effect and a magnetoresistant effect at low temperatures down to 0.4K. Pronounced Shubnikov-de Haas (SdH) oscillations were observed at a low temperature showing two dimensional electron gases (2DEG) in s tensile strained Si quantum well. The electron sheet density (ns) of $1.5\times10^{12}[\textrm{cm}^{-2}]$ and corresponding electron mobility of 14200 $[\textrm{cm}^2V^{-1}s^{-1}]$ were obtained at a low temperature of 0.4K from $Si/Si_{1-x}Ge_x$ structures with thermally grown oxides.

• 한국건설관리학회:학술대회논문집
• /
• 한국건설관리학회 2002년도 학술대회지
• /
• pp.188-191
• /
• 2002

This paper concerns 3-D graphical modeling and simulation techniques for design and control of automated equipment for construction and facility maintenance. A case study on the use of 3-D graphics techniques for developing a power plant maintenance robot is presented. By simulating equipment operation within the 3-D geometry models of the work environment the environment design was improved. The 3-D graphical models of the equipment and the work environment were further utilized for the control of the robot from a remote distance. By presenting the real-time updated equipment configuration and the work environment to the operator, the graphical model-based equipment control system helped the operator overcome the problems associated with spatial perception. The collision between the robot and the plant structures was also avoided based the real-time analysis of the dynamically updated graphical models.

• 한국환경보건학회:학술대회논문집
• /
• 한국환경보건학회 2005년도 국제학술대회
• /
• pp.259-262
• /
• 2005

This study aims to identify the relationship between characteristics of aqueous organic matter and chlorination by-products formation potential according to temporal effect of Juam reservoir in Sun-Choen. The molecular weight distribution and chemical composition of precursors and their relationship with disinfection by-products(DBPs) were investigated. Most of the organic matters was responsible for the major DBP precursors in the raw water are small compounds with a molecular weight less than IKDa, Aromatic contents determined by SUVA correlated well with DBPs, THMs, and HAAs formation. Especially, THMFP/DOC showed better correlation with SUVA than HAAFP/DOC and DBPFP/DOC with SUVA in Juam reservoir. Therefore, effective removal of small molecules or hydrophobic organic matter prior to disinfection process will significantly reduce the DBP concentration in the finished water.

• International Journal of Control, Automation, and Systems
• /
• 제1권4호
• /
• pp.431-443
• /
• 2003

This paper presents an efficient method to evaluate the performance of an extended stochastic Petri net by simple algebraic operations. The reachability graph is derived from an extended stochastic Petri net, and then converted to a timed stochastic state machine, using a semi-Markov process. The n-th moments of the performance index are derived by algebraic manipulations with each of the n-th moments of transition time and transition probability. For the derivation, three reduction rules are introduced on the transition trajectories in a well-formed regular expression. Efficient computation algorithms are provided to automate the suggested method. The presented method provides a proficient means to derive both the numerical and the symbolic solutions for the performance of an extended stochastic Petri net by simple algebraic manipulations.

• 건설관리
• /
• 제4권1호
• /
• pp.48-54
• /
• 2003

An automated system for scanning and characterizing unbound aggregates, called the 'Laser-based Aggregate Scanning System'(LASS), has been developed at the University of Texas at Austin. The system uses a laser profiler to acquire and analyze true three-dimensional data on aggregate particles to measure various morphological properties. Tests have demonstrated that the system can rapidly and accurately measure grain size distribution and dimensional ratios, and can objectively quantify particle shape, angularity, and texture in a size invariant manner. In its present state of development, the LASS machine is a first-generation, laboratory testing device. With additional development, this technology is expected to provide high-quality, detailed information for laboratory and on-line quality control during aggregate production.

• Toxicological Research
• /
• 제23권3호
• /
• pp.189-196
• /
• 2007

Cytochrome P450 (P450) enzymes are the major catalysts involved in the biotransformation of various drugs, pollutants, carcinogens, and many endogenous compounds. Most of chemical carcinogens are not active by themselves but they require metabolic activation. P450 isozymes playa pivotal role in the metabolic activation. The activation of arylamines and heterocyclic arylamines (HAAs) involves critical N-hydroxylation, usually by P450. CYP1A2 plays an important role in these reactions. Broad exposure to many of these compounds might cause carcinogenicity in animals and humans. On the other hand, P450s can be also involved in the bioactivation of other chemicals including alcohols, aflatoxin B1, acetaminophen, and trichloroethylene, both in humans and in experimental animals. Understanding the P450 metabolic activation of many chemicals is necessary to develop rational strategies for prevention of their toxicities in human health. An important part is the issues of extrapolation between species in predicting risks and variation of P450 enzyme activities in humans.

• 한국정밀공학회:학술대회논문집
• /
• 한국정밀공학회 2006년도 춘계학술대회 논문집
• /
• pp.479-480
• /
• 2006

The purpose of this paper is to investigate the relationship between CMP(Chemical Mechanical Polishing) characteristics of ITO thin film and friction signal by using the CMP monitoring system. Suba 400 pad and MSW2000 slurry of the Rohm & Haas Co. was used in this experiment to investigate the charateristics of ITO CMP. From this experiment, it is proven that the coefficient of friction is related to uniformity of the removal rate of the ITO thin film. Therefore, the prediction of polishing result would be possible by measuring friction signal.