• Safety and Health at Work
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• v.8 no.3
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• pp.237-245
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• 2017

Background: Solar furnaces are used worldwide to conduct experiments to demonstrate the feasibility of solar-chemical processes with the aid of concentrated sunlight, or to qualify high temperature-resistant components. In recent years, high-flux solar simulators (HFSSs) based on short-arc xenon lamps are more frequently used. The emitted spectrum is very similar to natural sunlight but with dangerous portions of ultraviolet light as well. Due to special benefits of solar simulators the increase of construction activity for HFSS can be observed worldwide. Hence, it is quite important to protect employees against serious injuries caused by ultraviolet radiation (UVR) in a range of 100 nm to 400 nm. Methods: The UV measurements were made at the German Aerospace Center (DLR), Cologne and Paul-Scherrer-Institute (PSI), Switzerland, during normal operations of the HFSS, with a high-precision UV-A/B radiometer using different experiment setups at different power levels. Thus, the measurement results represent UV emissions which are typical when operating a HFSS. Therefore, the biological effects on people exposed to UVR was investigated systematically to identify the existing hazard potential. Results: It should be noted that the permissible workplace exposure limits for UV emissions significantly exceeded after a few seconds. One critical value was strongly exceeded by a factor of 770. Conclusion: The prevention of emissions must first and foremost be carried out by structural measures. Furthermore, unambiguous protocols have to be defined and compliance must be monitored. For short-term activities in the hazard area, measures for the protection of eyes and skin must be taken.

• Microbiology and Biotechnology Letters
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• v.32 no.2
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• pp.101-109
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• 2004

In order to enhance the productivity of AVM $B_{la}$ produced by Streptomyces avermitilis as a secondary metabolite, we established a basic protocol necessary for protoplast fusion with high-producing strains as a fusion partner, and then obtained various kinds offusants by adopting a massive strain-development procedure (a miniaturized strain screening system). An alternative fusion method using UV and/or NTG mutation of protoplasts was developed to screen genetic recombinants without specific selectable markers. In this method, the mutants obtained by protoplast fusion after UV and/or NTG treatment (95% death rate) of the respective fusion partner (protoplasts of the respective mutants resistant against L-isoleucine antimetabolites such as O-methylthreonine and/or azaleucine) were regarded as DNA-recombined protoplast fusants. Notably it was demonstrated that most of the protoplast recombinants obtained by the UV mutation method were able to biosynthesize higher amount of AVM $B_{la}$ , reaching almost three times higher level (almost equal to the industrial productivity), compared to the average AVM Bla amount of the parallel mother strains.

• Proceedings of the KIEE Conference
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• 1996.07c
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• pp.1697-1699
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• 1996

EPDM compound can be cured with either the sulfur and peroxide based systems. In this study, heat resistance and weatherability of EPDM compounds depending on curing systems were investigated. The test results showed that the peroxide-cured EPDM was more resistant to heat ageing and UV photo-degradation than the sulfur-cured EPDM and it is due to C-C bond is more stable than C-S, S-S bond.

• 한국정보디스플레이학회:학술대회논문집
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• 2002.08a
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• pp.456-458
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• 2002

On the half area of a pixel, pretilt angle was decreased by UV radiation and two domain TN was induced by the pretilt difference. In this structure, ITO slit was made inside pixel electrode on the TFT substrate to stabilize domain boundaries. The result shows that this structure is more resistant to outside stress and unwanted domain deformation is prevented.

• Microbiology and Biotechnology Letters
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• v.22 no.5
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• pp.491-494
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• 1994

Antibiotic HS-2 was purified from the culture broth of Streptomyces plicatosporus which was isolated from soil, by solvent extraction, silica gel column chromatography and gel filtration. Through the analysis of UV, $^{1}$H-NMR, $^{13}$C-NMR spectrum, HS-2 was identified as rubiginone B$_{2}$. It was confirmed that HS-2 enhanced the cytotoxicity of colchicine against multidrug-resistant tumor cells.

• Journal of the Korean Graphic Arts Communication Society
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• v.10 no.1
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• pp.1-13
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• 1992

The recent results concerning the synthesis and application of spiroxazine dyes have been summerized., The absorption bands of usual spiroxazine dyes are changed from colorless to colored from by irradiation of ultraviolet ray. This mechanism is derived from the cleavage of oxazine ring. Such properties are dependent on its chemical structure and surrounded matrix of spiroxazine dyes. the chemical structure of this dye is similar to the well known spriopyran. But spiroxazine dyes have noticed recently, because of excellent high light-sensitivity and superior fatigue-resistant property. This dye are already applied as photochromic lens, cloths and UV light checker.

• Journal of Species Research
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• v.7 no.3
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• pp.202-209
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• 2018

Eight bacterial strains, 18JY8-13, 18JY13-16, 18JY43-7, 18JY12-7, 18JY1-1, 18JY1-7, 18JY15-3, and 18JY7-2 assigned to the phylum Firmicutes were isolated from a variety of soil samples collected in the Jeju Island, Korea. Cells of the eight strains were Gram-positive, aerobic and showed resistant to UV-radiation. Phylogenetic analysis based on 16S rRNA gene sequence revealed that strains 18JY8-13, 18JY13-16, 18JY43-7, 18JY12-7, 18JY1-1, 18JY1-7, 18JY15-3, and 18JY7-2 were most closely related to Bacillus paranthracis(99.9%), Bacillus paramycoides(99.6%), Bacillus australimaris(99.9%), Bacillus wiedmannii (100%), Bacillus halosaccharovorans(99.6%), Bacillus deserti(98.7%), Bacillus cereus (99.8%), and Bacillus albus(100%), respectively. This is the first report of these eight species in Korea.

• Journal of Microbiology
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• v.33 no.3
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• pp.215-221
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• 1995

S. coelicolor A3(2) cells were treated with various redox-cycling agents on nutrient agar plates and examined for their effect on the growth and differentiation. When treated with plumbagin, severe effect on cell viability was observed at concentrations above 250 $\mu$M. However, the surviving colonies differentiated normally. When treated with 100 $\mu$M paraquat, growth rate was decreased and morphological differentiation was inhibited, while the survival rate was maintained at about 100% even at 5 mM paraquat. Menadione or lawsone did not cause any visible changes at concentrations up to 1 mM. The effect of paraquat was also observed when it was added to nutrient agar plate before spore inoculation. Paraquat had also observed when it was added to nutrient agar plate before spore inoculation. Paraquat had no effect on colonies growing on R2YE agar plates. Among the components of R2YE medium selectively added to nutrient agar medium, CaCl$_2$ was found to have some protective function from the inhibitory effect of paraquat. As a first step to study the mechanism of the inhibitory effect of paraquat on differentiation, resistant mutants which sporulate well in the presence of paraquat were screened following UV mutagenesis. Three paraquat-resistant mutants were isolated with a frequency of 3 $\times$10${-5}$. Their mutation sites were determined by genetic crossings. All three mutations were mapped to a single locus near arg4 at about 1 o'clock on the genetic map of S. coelicolor A3(2).

• Journal of Life Science
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• v.12 no.2
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• pp.219-225
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• 2002

The organization of eukayotic chromatin into specific conformation that are associated with transcription, replication, reapir and other nuclear processes are achieved via a series of DNA-protein interaction. These interactions are mediated by a range of DNA-binding domains such as SAP domain et at. By searching S. pombe genomic DNA database, we have found a gene named SAPuvs (SAP UV Sensitive) whose amino acid sequence is in part similar to SAP domain of Arabidopsis poly (ADP-ribose) polymerase and Ku7O. Knock-out cell of S. pombe SAPuvs gene was constructed using Ura4 as a selection marker. Survival analysis of knock-out cell indicated that treatment with UV significantly reduces the survival compared to wild type cell. Potentiation of MMS-induced cytotoxicity by 3AB post-treatment was observed in wild type cells, but not in knock-out cells. These data suggested that the protein encoded by SAPuvs gene is associated with chromatin reorganization during DNA repair.

• Molecules and Cells
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• v.43 no.8
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• pp.694-704
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• 2020

HslUV is a bacterial heat shock protein complex consisting of the AAA+ ATPase component HslU and the protease component HslV. HslV is a threonine (Thr) protease employing the N-terminal Thr residue in the mature protein as the catalytic residue. To date, HslUV from Gram-negative bacteria has been extensively studied. However, the mechanisms of action and activation of HslUV from Gram-positive bacteria, which have an additional N-terminal sequence before the catalytic Thr residue, remain to be revealed. In this study, we determined the crystal structures of HslV from the Gram-positive bacterium Staphylococcus aureus with and without HslU in the crystallization conditions. The structural comparison suggested that a structural transition to the symmetric form of HslV was triggered by ATP-bound HslU. More importantly, the additional N-terminal sequence was cleaved in the presence of HslU and ATP, exposing the Thr9 residue at the N-terminus and activating the ATP-dependent protease activity. Further biochemical studies demonstrated that the exposed N-terminal Thr residue is critical for catalysis with binding to the symmetric HslU hexamer. Since eukaryotic proteasomes have a similar additional N-terminal sequence, our results will improve our understanding of the common molecular mechanisms for the activation of proteasomes.