• Journal of the Korean Society of Clothing and Textiles
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• v.37 no.5
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• pp.667-675
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• 2013

After analyzing excavated $17-18^{th}$ century silk fibers through a scanning electron microscopy, we discovered seven different kinds of fracture morphology. Using Morton & Hearle fiber fracture morphology, we classified the findings into four different categories. Type I is tensile failure resulting from brittle fracture, granular fracture, and ductile fracture. Type II is fatigue failure caused by tensile fatigue, flex fatigue, and axial split (fibrillation). Type III is bacterial deterioration discovered only in excavated artifacts. Type IV is a combination of the three above. Humid underground conditions and the infiltration of bacteria caused the fibers to swell and weaken its interfibrillar cohesion. Fractures occur when drying and processing an excavated artifact that is already in a fragile condition. Therefore, one must minimize damage through a prompt cleaning process and make sure that the least possible force is exerted on the fabric during any treatment for repair and exhibition.

• Proceedings of the Korean Society for Applied Microbiology Conference
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• 1976.04a
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• pp.184.3-184
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• 1976

제탁의 목적으로 맥주에 첨가한 Ppain이 숙성 도중에 어느정도 맥주의 발포성을 손상시키는가를 확인하기 위하여 발효가 끝난 처녀맥주에 30ppm의 papain을 첨가하고 $0^{\circ}C에서$ 22일동안 정치하면서 발포성을 조사해 보았다. 그 결과로써 pasteurization 과정을 밟지 않아도 30ppm의 papain은 맥주의 발포성을 현저히 손상시키는 사실이 알려졌다. 시판중의 3가지 papin 제품이 모두 같은 결과를 보였으며 papain의 농도를 5~15ppm으로 줄이면 발포성의 손실도 줄어졌다.

• Bulletin of Food Technology
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• v.13 no.2
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• pp.3-13
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• 2000

신선 과일, 채소 편의식품의 주요 특징으로는 박피, 절단 등에 의한 식물조직의 손상, 최소가공에 따른 제품의 불확실한 미생물 안전성, 식물 조직의 활발한 물질대사, 제품 종류의 제한 등을 들 수 있다. 따라서 이들 제품에서는 미생물이 증식하기 쉬우나 실제 미생물의 거동은 식물조직의 대사에 의해 영향을 받으며, 또한 생체의 호흡과 필름 포장재의 기체투과도에 의해 좌우되는 포장내부 환경기체에도 영향을 받는다. 수확후 감염은 과일, 채소와같은 원료 농산물의 주요 손실요인으로(Harvey, 1978;Lund, 1983) 신선 과채류 편의식품의 경우 절단면의 노출과 포장내부의 고수분 함량 등에 의해 미생물 감염의 위험은 더욱 더 증가할 수 있다. 특히 대부분의 신선 편의식품이 어떠한 가열처리도 없이 그대로 이용되므로 식품유래 병원균의 오염과 저장중 이들의 증식은 각별한 관심의 대상이 되고 있다. 이에 본고에서는 현재 과채류 편의식품에 주로 사용되고 있는 미생물 오염 방지 또는 조절 방법에대해 설명하고 이의 적용과 관련한 주의사항을 살펴보고자 한다.

• Korean Journal of Food Science and Technology
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• v.47 no.1
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• pp.87-94
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• 2015

High voltage pulsed electric fields (PEF) treatment is one of the more promising nonthermal technologies to fully or partially replace thermal processing. The objective of this research was to investigate the microbial inactivation mechanisms of PEF treatment in terms of intra- and extracellular changes in the cells. Saccharomyces cerevisae cells treated with PEF showed cellular membrane damage. This resulted in the leakage of UV-absorbing materials and intracelluar ions, which increased with increasing treatment time and electric fields strength. This indicates that PEF treatment causes cell death via membrane damage and physical rupture of cell walls. We further confirmed this by Phloxine B staining, a dye that accumulates in dead cells. Using scanning and transmission electron microscopy, we observed morphological changes as well as disrupted cytoplasmic membranes in PEF treated S. cerevisae cells. In addition, PEF treatment led to damaged chromosomal DNA in S. cerevisiae.

• Korean Journal of Food Science and Technology
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• v.47 no.1
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• pp.81-86
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• 2015

Intense pulsed light (IPL), a nonthermal technology, has attracted increasing interest as a food processing technology. However, its efficacy in inactivating microorganisms has not been evaluated thoroughly. In this study, we investigated the influence of IPL treatment on the inactivation of Escherichia coli O157:H7 depending on light intensity, treatment time, and pulse number. Increased light intensity from 500 V to 1,000 V, raised the inactivation rate at room temperature. At 1000 V, the cell numbers were reduced by 7.1 log cycles within 120 s. In addition, increased pulse number or decreased distance between the light source and sample surface also led to an increase in the inactivation rate. IPL exposure caused a significant increase in the absorption at 260 nm of the suspending agent used in our experiments. This indicates that IPL-treated cells were damaged, consequently releasing intracellular materials. The growth of IPL-irradiated cells were delayed by about 5 h. The degree of damage to the cells after IPL treatment was confimed by transmission electron microscopy.

• Microbiology and Biotechnology Letters
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• v.20 no.3
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• pp.243-248
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• 1992

In order to examine the viability depending on rehydration process and membrane injury of Nocardia mediterranei upon lyophilization, We labeled $3^H$-thymidine in deoxyribonucleic acid of N. mediterrranei to obtain information on the mechanisms of injury caused by lyophilization. Suspensions of rehydrated cells were incubated with added DNase in a buffer solution. Extracellular radioactivity levels appeared to be high in the rehydrated solutions after lyophilization than freezing-thawing. Thus, the membrane systems were injured by lyophilization, but not ovenvhelmed. These considerations were confirmed by electron microscopy. In effects of rehydration, the cell membrane was seriously damaged by strong atmospheric pressure as soon as the inner ampule was opened, but this was not the case without admitting air under vacuum. N. rnediterranei cells, with no additives, were lyophilized and reconstituted without admitting air, virtually about 84% of the cells were viable.

• Journal of Conservation Science
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• v.27 no.2
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• pp.155-162
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• 2011

In case of leather objects, degradation usually occurs by a combination of factors such as temperature and relative humidity, light and insect and fungi. Because chemical composition differs on the types of leather materials, leather objects affect differently even in the same environment. According to UV degradation, the overall color and gloss difference appeared severe in turn of the cowskin, sheepskin and pigskin specimens. In addition, despite short-term period of RH degradation, leather materials showed stable result on high RH circumstances. Nevertheless, if the leather sustained for a long time on the high RH, the environment can be the cause of mold or microorganisms. This study is to understand the leather objects and the future conservation and then to establish the conservational management of leather object for the future.

• Journal of Conservation Science
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• v.26 no.4
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• pp.385-395
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• 2010

This study aimed to identify weathering factors and to assess the conservation environment through microclimatic analysis of Hyeonpung Seokbinggo (ice-storing stone warehouse). The stone blocks inside Seokbinggo suffered crack, displacement, break-out, exfoliation, efflorescence, brown and black discoloration, and biological colonization. Biological colonization represented the maximum deterioration rate(24%) among those weathering forms. The indoor microclimate showed parallel patterns with outdoor one, but the indoor temperature and relative humidity ranged far narrower than outdoor and remained steady. The environmental characteristics resulted from blocking-out of outdoor heat by the closed entrance and surrounding microtopography. This prevented water condensation and freezing effects, so that it reduced physical deterioration of rock, and maximized ice-storing effect for long time. However, contrary to positive effect, extremely high relative humidity over 99% accelerated biological colonization inside the Seokbinggo.

• 보존과학연구
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• s.32
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• pp.137-153
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• 2011

Paper cultural heritages in museums and libraries are deteriorated by many biological factors like as fungi, insects, bacteria and rodents and get irreversibly damaged. Especially, paper components like as cellulose, hemicellulose, lignin, pectins, tannins, proteins and mineral additives are good nourishment for microorganism. Through some studies on fungi causing the aging of paper materials, Aspergilli (about 30%) and Penicilli (more than 30%) are the most common among 300 different kinds of microorganism that caused the biological aging of paper cultural heritages in museums and libraries. At present, various treatments are attempted to control the biodeterioration by these fungi. Especially, it is focused on the control of environmental factors such as humidity, temperature and oxygen. In this study, the oxygen absorbent was used to control oxygen, one of the these favorable conditions during the biological aging of Hanji by Aspergillus versicolor and Penicillium polonicum and then the effect on prevention in aging by this treatment was investigated. In result, the oxygen absorbent treatment had the good effect on prevention in aging during the biological aging by two species of fungi.

• Korean Journal of Microbiology
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• v.47 no.2
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• pp.124-129
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• 2011

The role of the ferric uptake regulator (Fur) of Helicobacter pylori in the oxidative stress was investigated in this study. A fur knockout mutant of H. pylori was constructed by replacing the fur gene with an aphA (kanamycin resistant marker) gene. Photodynamic therapy using methylene blue (MB) and 660 nm light was chosen to induce oxidative stress. The bactericidal effect of photodynamic therapy (PDT) was compared between wild type H. pylori and fur knockout mutant H. pylori. The degree of oxidative damage of DNA was confirmed using alkaline gel electrophoresis and an assay of 8-hydroxy-2-deoxyguanosine (8-OHdG). In control groups, the number of viable cells was maintained constantly during experiment. After PDT, the mutant H. pylori showed 10,000 times decreased viable cell number compared with wild type H. pylori. Depending on the exposure time of 660 nm light, the 3-fold increase in the concentration of 8-OHdG was observed in mutant H. pylori. The results of this study showed that H. pylori's Fur protein may play a role in oxidative stress induced by PDT.