• 대한화장품학회지
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• 제26권2호
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• pp.41-50
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• 2000

- Biochemical studies show that in the process of mixed melanogenesis, cysteinyldopas are produced first which are next oxidized to give pheomelanin. After all of the cysteine is consumed, eumelanin is then deposited on the preformed pheomelanin. - In vitro and in vivo studies show that tyrosinase activity is the most important factor that regulates the switch of melanogenesis, with higher activities increasing melanogenesis, especially eumelanogenesis. - In culturted melanocytes, the tyrosine to cysteine ratio is critical in determining the eumelanin to pheomelanin ratio. - Our HPLC method to analyze eumelanin and pheomelanin has become a useful tool in the study of melanogenesis regulation. There are many problems to be solved before we fully understand the regulation of melanogenesis. Mutations in mouse models are ideal models for studying the genetic and molecular control of melanogenesis. Even in the mouse models, it is not known how cysteine is excluded from being incorporated into melanins in black and other eumelaninc mice, Conversely, it is not known how cysteine is continuously incorporated into pheomelanin in lethal yellow and recessive yellow mice.

• BMB Reports
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• 제57권3호
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• pp.135-142
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• 2024

DNA methylation is one of the most extensively studied epigenetic regulatory mechanisms, known to play crucial roles in various organisms. It has been implicated in the regulation of gene expression and chromatin changes, ranging from global alterations during cell state transitions to locus-specific modifications. 5-hydroxymethylcytosine (5hmC) is produced by a major oxidation, from 5-methylcytosine (5mC), catalyzed by the ten-eleven translocation (TET) enzymes, and is gradually being recognized for its significant role in genome regulation. With the development of state-of-the-art experimental techniques, it has become possible to detect and distinguish 5mC and 5hmC at base resolution. Various techniques have evolved, encompassing chemical and enzymatic approaches, as well as third-generation sequencing techniques. These advancements have paved the way for a thorough exploration of the role of 5hmC across a diverse array of cell types, from embryonic stem cells (ESCs) to various differentiated cells. This review aims to comprehensively report on recent techniques and discuss the emerging roles of 5hmC.

• 한국환경보건학회지
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• 제49권4호
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• pp.179-182
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• 2023

The Chemical Substances Control Act has been legislated to counter the risks posed by chemical substances to public health and the environment, but a number of small- and large-scaled incidents related to hazardous chemicals continue to occur every year. The Korean Ministry of Environment takes legal responsibility for prevention, preparedness, and response to nationwide chemical accidents under the Chemical Substances Control Act. The determination of chemical accidents that occur during hazardous chemical handling processes is based on the Article 2 (Definitions) of the law and the administrative criteria for judgement of chemical accidents. However, there are certain ambiguities in the scientific basis for determining chemical accidents under the current regulations. Whether or not a chemical accident has a direct influence on penalties and administrative measures for a workplace where an accident occurred, it is necessary to find reasonable criteria for determining chemical accident based on legal and scientific evidence.

• Journal of Microbiology and Biotechnology
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• 제10권1호
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• pp.51-55
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• 2000

Surface culture fermentation using Aspergillus niger was studied for gluconic and citric acid production at different C/N ratios. A culture of A. niger was found to produce either gluconic acid alone, a mixture of gluconic and citric acid, or citric acid alone depending on the level of nitrogen in the medium (4 to 18mM). Glucose oxidase from the mycelial mat was also analyzed at different levels of nitrogen in the media. By choosing the level of nitrogen in the medium at the start of fermentation, it is possible to produce either of the two acids as the dominant product or the two together as a mixture.

• 한국가스학회지
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• 제6권1호
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• pp.24-31
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• 2002

기업의 안전$\cdot$보건, 환경(SHE: Safety, Health and Environment)과 관련된 사고는 큰 인적$\cdot$물적 손실을 가져오기 때문에 사회적 책임에 관한 문제로 확산되고 있는 추세이다. 따라서 기업은 SHE 문제에 대해 수동적$\cdot$소극적인 대응에서 벗어나 자발적인 SHE 관리수행이 필요하게 되었다. 본 연구에서는 국내 기업의 SHE 관리 실태를 조사하여 연구$\cdot$분석하고. 그 결과를 활용하여 기업 스스로 자율적인 SHE 관리를 수행할 수 있는 KW{Kwangwoon}_SHE(Safety, Health and Environment) 관리 모델을 제시하였다. 이 모델은 SHE 관리에 있어서 관리비 투자에 대한 업무 성과를 손쉽게 평가할 수 있도록 하였다.

• 분석과학
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• 제34권3호
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• pp.99-114
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• 2021

물질확인은 화학물질 등록법에서 수행해야 하는 첫 단계로 올바른 물질확인은 이어지는 유해성 및 위해성 평가를 정확하게 효율적으로 하는데 필수적이다. 이에 톤수별 물질 등록을 모두 마친 EU REACH의 물질확인 절차를 유럽화학물질청 홈페이지 및 관련 지침서와 컨소시움 자료를 참고하여 살펴 보았고 물질확인과 물질의 동질성 확인 그리고 이를 위한 물질확인 프로파일 생성의 중요성을 고찰해보았다. 또한 기기분석에 의한 분석 결과 중 어떤 정보를 어떻게 정리하여 물질확인 프로파일을 생성하는지에 초점을 맞추어 몇 개 주요 유형별 물질을 사례로 제시해보았다. 분석과학은 화학물질 등록법이 정확하고 효율적으로 이행될 수 있도록 첫 단계인 물질확인에서 기여를 할 수 있는데 단, 법에 대한 이해를 기반으로 같은 물질의 등록자들의 분석 결과를 물질확인 프로파일로 최종 정리하여 공동 등록을 하는 등록자들과 관계 당국과 소통하는 것이 필수적이다.

• Journal of Microbiology and Biotechnology
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• 제30권8호
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• pp.1124-1131
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• 2020

Techniques used for the regulation of gene expression facilitate studies of gene function and treatment of diseases via gene therapy. Many tools have been developed for the regulation of gene expression in mammalian cells. The Lac operon system induced with isopropyl β-D-1-thiogalactopyranoside (IPTG) is one of the employed inducible systems. IPTG mimics the molecular structure of allolactose and has a strong affinity for the corresponding repressor. IPTG is known to rapidly penetrate into mammalian cells and exhibits low toxicity. In the present study, we developed a new inducible expression system that could regulate the expression of genes in mammalian cells using IPTG. Here we confirm that unlike other vector systems based on the Lac operon, this expression system allows regulation of gene expression with lactose in the mammalian cells upon transfection. The co-treatment with IPTG and lactose could improve the regulatory efficiency of the specific target gene expression. The regulation of gene expression with lactose has several benefits. Lactose is safe in humans as compared to other chemical substances and is easily available, making this technique very cost-effective.

• 약학회지
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• 제53권3호
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• pp.156-160
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• 2009

The present study was undertaken to determine whether transgelin participates in the regulation of vascular smooth muscle contraction and, if so, to investigate the mechanism. By PCR homology cloning, the cDNA sequence of ferret transgelin was determined and phosphorothioate antisense and random oligonucleotides were synthesized and introduced into strips of ferret aorta by a chemical loading procedure. Treatment of ferret aorta with transgelin antisense oligonucleotides resulted in a significant decrease in protein levels of transgelin to sham- or random sequence-loaded muscles, but no change in the protein levels of actin. Contraction in response to a phorbol ester was significantly decreased in antisense-treated muscles compared to sham- or random sequence-loaded controls. Neither basal intrinsic tone nor the contraction in response to phenylephrine was significantly affected by the antisense treatment. The data indicate that transgelin plays a significant role in the regulation of contraction and suggest that in a tonically active smooth muscle transgelin may function as a signalling protein to facilitate PKC or ERK-dependent signalling rather than thick filament regulation including $Ca^{2+}$ or calmodulin dependent regulation of myosin light chain kinase.

• Bulletin of the Korean Chemical Society
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• 제29권8호
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• pp.1633-1636
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• 2008

• International Journal of Contents
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• 제12권3호
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• pp.17-21
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• 2016

The purpose of this study was to obtain qualitative data on Korean-American dry cleaners' concerns about work-related health and safety and their attitudes toward the use of PPE(Personal Protective Equipment). Two focus group discussions were conducted with convenient samples of Korean-American drycleaners in middle-eastern state. A total of 13 individuals participated in two focus groups. Participants had concerns as both owners and workers. As owners, they were concerned mostly about compliance of environmental regulation and economic depression. The participants knew very little about the hazards of chemical exposure and expressed vague concerns about chemical exposure and health. Majority of participants do not use PPE and had no intention of using it in the future because of their limited knowledge about the hazardous nature of chemical exposure. The findings from this study would guide the development of intervention to increase drycleaners knowledge of chemical exposure and use of PPE.