• 한국산업보건학회지
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• 제25권2호
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• pp.166-173
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• 2015

Objectives: The purpose of this study was to evaluate cobalt concentrations in airborne inhalable, total and respirable dust from manufacturing industries using cobalt. Methods: To compare cobalt concentrations, three types of dust samplers(a 37mm closed cassette sampler, Institute of Occupational Medicine(IOM) sampler, and Aluminum cyclone sampler) were used. The analysis of cobalt concentrations was conducted using AAs based on the NIOSH 7300 method. Results: The geometric mean of cobalt concentration in total dust was $1.47{\mu}g/m^3$, and the rate of excess of the Korean Occupational Exposure Limit(KOEL) was 10.0%. The geometric mean concentrations of cobalt in super alloy manufacturing industries were higher than those in plating industries, and molding operations showed higher exposure levels to cobalt than did other operations. Conclusions: The rate of cobalt concentration in inhalable dust from super alloy manufacturing industries exceeding the Workplace Exposure Limit(WEL) as recommended by the Health & Safety Executive(HSE) was 7.1%, which means proper work environmental management is required through wet work environments. Given that molding operations had higher cobalt concentrations, it is necessary to apply measures such as local exhaust for reducing airborne dust in cobalt manufacture industries.

• 한국산업보건학회지
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• 제27권4호
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• pp.390-397
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• 2017

Objectives: The purpose of this study was to evaluate concentrations in airborne total and respirable dusts in the cement manufacturing and handling industries. Methods: Fifty-three total dust and 42 respirable dustsamples were collected from 24 work places. Total dust samples were collected using a three-stage cassette. Respirable dust samples were collected using a cyclone equipped with a 37 mm, $5{\mu}m$ pore size PVC filter. Results: The geometric means of the dust concentrations were $0.10mg/m^3$ and $0.08mg/m^3$ in total dust and respirable dust, respectively. The Korean Occupational Exposure Limit($10mg/m^3$) was not exceeded, but the rate of exceeding the American Conference of Governmental Industrial Hygienist(ACGIH) Threshold Limit Value($1mg/m^3$) was 16.7%. Conclusion: When measuring the level of dust at cement manufacturers, the airborne concentration of respirable dust should be evaluated. In order to protect the health of workers exposed to cement dust, it is necessary to actively consider strengthening the Korean Occupational Exposure Limit.

• 정보관리연구
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• 제35권2호
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• pp.41-55
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• 2004

본 연구에서는 딸림자료 중 특히, 오디오 테이프 형태의 자료를 디지털화하여 멀티미디어 데이터베이스를 구축함으로써 이용자의 이용편의와 자료관리의 효율성을 제고하는 것에 대한 방안에 대해 논의하고자 한다. 이를 위해 본고에서는 딸림자료의 관리현황, 오디오 데이터 포맷의 종류, 데이터 포맷변환, 관리 및 이용방안 등을 살펴보았다. 또한, 딸림자료의 멀티미디어 데이터베이스 구축을 통한 기대효과 및 문제점을 제시하였다.

• Molecules and Cells
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• 제38권11호
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• pp.959-965
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• 2015

Inducible and reversible gene silencing in desired types of cells is instrumental for deciphering gene functions using cultured cells or in vivo models. However, efficient conditional gene knockdown systems remain to be established. Here, we report the generation of an inducible expression system for short hairpin RNA (shRNA) targeted to PTEN, a well-documented dual-specificity phosphatase involved in tumor suppression and ontogenesis. Upon induction by doxycycline (DOX), the reverse tetracycline transcriptional activator (rtTA) switched on the concomitant expression of GFP and a miR-30 precursor, the subsequent processing of which released the embedded PTEN-targeted shRNA. The efficacy and reversibility of PTEN knockdown by this construct was validated in normal and neoplastic cells, in which PTEN deficiency resulted in accelerated cell proliferation, suppressed apoptosis, and increased invasiveness. Transgenic mice harboring the conditional shRNA-expression cassette were obtained; GFP expression and concurrent PTEN silencing were observed upon ectopic expression of rtTA and induction with Dox. Therefore, this study provides novel tools for the precise dissection of PTEN functions and the generation of PTEN loss of function models in specific subsets of cells during carcinogenesis and ontogenesis.

• Journal of Microbiology
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• 제45권5호
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• pp.379-387
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• 2007

A hundred and seventeen antibiotic-resistant Escherichia coli strains were isolated from public tap and spring waters which were polluted by fecal coliforms. There were no significant differences between two water sources as to the coliform pollution level (p> 0.05). All E. coli isolates were detected to be resistant to one or more antibiotics tested. Nearly 42% of the isolates showed multiresistant phenotype. Three (2.5%) of these isolates contained class 1 integron. Sequencing analysis of variable regions of the class 1 integrons showed two gene cassette arrays, dfr1-aadA1 and dhfrA17-aadA5. Resistance to ampicillin, tetracycline or trimethoprim-sulfamethoxazole was transferable according to the results of conjugation experiments. The rate of tetracycline resistance was 15%. tet(A)-mediated tetracycline resistance was widespread among tetracycline-resistant E. coli isolates. Genotyping by BOX-polymerase chain reaction (BOX-PCR) showed that some of the strains were epidemiologically related. This is the first report on the prevalence and characterization of class 1 integron-containing E. coli isolates of environmental origin in Turkey.

• 한국미생물학회:학술대회논문집
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• 한국미생물학회 2000년도 International Meeting 2000
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• pp.58-65
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• 2000

Diarrheal diseases are a major cause of both illness and death in developing countries and are caused by rotavirus, Shigella spp., Salmonella spp., enterotoxigenic Escherichia coli (ETEC), and Vibrio spp. In this study, for the development of vaccine against diarrheal diseases caused by Shigella sonei, Salmonella typhimurium, E. coli O157, and Vibrio cholerae, cloning and nucleotide sequence analysis of genes and characteristics of their gene products in E. coli were performed. For construction of attenuated strain of S. sonnei KNIH104 and Salmonella typhimurium KNIH100, the aroA genes were cloned, respectively. The recombinant plasmid $_pJP{\Delta}A45$ containing aroA deleted region and suicide vector $(_pJP5603)$ was constructed. The aroA gene deleted mutants were constructed using this recombinant plasmid. For cloning gene encoding antigenic region of E. coli O157 KNIH317, the O-antigen synthesis gene cluster and sit gene was cloned. The E. coli XL1-Blue cells harboring this recombinant plasmid showed cytotoxicity in Vero cells. The ctx gene was cloned for tile purpose of antigenic region against V. cholerae KNIH002. Sequence analysis confirmed that the virulence gene cassette was consisted of ace, zot, ctxA and ctxB genes.

• Journal of Microbiology and Biotechnology
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• 제26권11호
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• pp.1983-1992
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• 2016

Pseudomonas strains isolated from the heavily contaminated Lubin copper mine and Zelazny Most post-flotation waste reservoir in Poland were screened for the presence of integrons. This analysis revealed that two strains carried homologous DNA regions composed of a gene encoding a DNA_BRE_C domain-containing tyrosine recombinase (with no significant sequence similarity to other integrases of integrons) plus a three-component array of putative integron gene cassettes. The predicted gene cassettes encode three putative polypeptides with homology to (i) transmembrane proteins, (ii) GCN5 family acetyltransferases, and (iii) hypothetical proteins of unknown function (homologous proteins are encoded by the gene cassettes of several class 1 integrons). Comparative sequence analyses identified three structural variants of these novel integron-like elements within the sequenced bacterial genomes. Analysis of their distribution revealed that they are found exclusively in strains of the genus Pseudomonas.

• 설비공학논문집
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• 제29권2호
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• pp.74-81
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• 2017

In this study, the combined-type diffuser developed by the Authors, in a previous study, was applied to a residential space. The performance of a ventilation and thermal environment, created by the use of a combined-type diffuser was compared to the pan-type diffuser widely used in apartment houses. In cooling conditions, because of the relatively high air flow rate of ceiling cassette-type air conditioners, the characteristics of airflow distribution in a room were governed by the air conditioner's airflow. In heating conditions, because of the low air flow rate of the diffuser, the characteristics of airflow distribution were governed by the buoyancy effect created by cold external walls and a hot floor. In terms of the Air Diffusion Performance Index (ADPI), which is a thermal environmental index, the result of a combined-type diffuser was greater than a pan-type diffuser in both of cooling and heating conditions. Consequently, the combined-type diffuser showed equal or superior ventilation and thermal environment performance compared to a pan-type diffuser.

• 대한인간공학회:학술대회논문집
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• 대한인간공학회 1997년도 추계학술대회논문집
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• pp.179-185
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• 1997

작업장 뿐만 아니라 일상생활에서도 결코 무시될 수 없는 것이 레져활동으로 인한 소음이다. 최근 급격히 늘어가는 개인 휴대용 카세트(Personal Cassette Players: PCP)사용은 심각한 소음성난청 발생이 우려된다. 본 연구는 PCP사용에 관련된 여러 인자들이 청력손실과 어떻게 얼마나 관련이 있는가를 파악 하고 PCP를 일정시간 사용했을 때 오는 청력 손실을 정량적으로 파악, 분석하는데 근본 목적을 둔다. 정상 청력을 가진 피실험자 18명의 대학생들을 대상으로 정상 청취조건 그리고 배경소음(지하철)에 노출 중과 후의 사용환경과 소음원으로 Hard Music, Soft Music 및 Language/News를 고려하여 평균소음도와 최고 소음도를 측정하였다. 또한 현실적 상황을 고려한 2시간 정도의 PCP의 청취 전과 후의 청력변화를 측정하였다. 통계 분석 결과, 사용환경과 소음원에 대해 휴대용 카세트 청취 소음수준이 유의한 차이가 있었으며, 특히 Hard Music 청취시에는 95dB, 그리고 지하철 소음하에서는 92dB의 높은 (위험한) 청취수 준을 보였다. 최고소음수준의 경우 NIOSH기준을 초과하는 117dB 정도의 매우 위험한 수준까지 나타났다. 또한 2 시간 정도의 PCP소음에 노출 전 후의 청력손실이 주파수 대역에 걸쳐 유의하게 나타났으며, 특히, 가장 민감한 주파수 대역인 4000Hz에서 최고 7dB 정도의 청력 손실이 발생하였다. 본 연구 결과에 따라, PCP사용에 대한 청력보호대책안을 제시하고자 한다.

• 한국컴퓨터정보학회논문지
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• 제21권12호
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• pp.139-145
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• 2016

In this paper, we propose to evaluate the effect of Resistin-like molecule alpha (Retnla) on the expression of transporters involved in modulating concentrations of peripheral cholesterol and plasma high-density lipoprotein (HDL) cholesterol. High levels of blood cholesterol are a well-recognized risk factor for atherosclerosis and are eliminated via the process of reverse cholesterol transport (RCT). We recently showed that Retnla ameliorates hypercholesterolemia and atherosclerosis by increasing biliary cholesterol secretion, the final step of the process, in low-density lipoprotein receptor-deficient mice. However, the role of Retnla in HDL-mediated cholesterol efflux, initial step of RCT pathway, is not yet clear. To identify cholesterol transport genes regulated by Retnla, we performed an extensive microarray-based gene expression screen using livers from Retnla-overexpressing (Tg) mice and control animals. The most significant change in Retnla-Tg mice was an upregulation of ATP-binding cassette sub-family G member 4 (Abcg4) transport and was validated using quantitative RT-PCR. The validated gene was also induced by treatment of purified Retnla protein in RAW 264.7 cells incubated with acetylated low-density lipoprotein and Hepa1c1c7 cells. Taken together, these results indicates that Retnla might also accelerate initial step of RCT pathway, suggesting therapeutic value of Retnla in the treatment of hypercholesterolemia and atherosclerosis.