• 한국자원식물학회지
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• 제30권3호
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• pp.265-271
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• 2017

In this study, we elucidated the molecular mechanism of silymarin by which silymarin may inhibits cell proliferation in human colorectal cancer cells in order to search the new potential anti-cancer target associated with the cell growth arrest. Silymarin reduced the level of c-Myc protein but not mRNA level indicating that silymarin-mediated downregulation of c-Myc may result from the proteasomal degradation. In the confirmation of silymarin-mediated c-Myc degradation, MG132 as a proteasome inhibitor attenuated c-Myc degradation by silymarin. In addition, silymarin phosphorylated the threonine-58 (Thr58) of c-Myc and the point mutation of Thr58 to alanine blocked its degradation by silymarin, which indicates that Thr58 phosphorylation may be an important modification for silymarin-mediated c-Myc degradation. We observed that the inhibition of ERK1/2, p38 and $GSK3{\beta}$ blocked the Thr58 phosphorylation and subsequent c-Myc degradation by silymarin. Finally, the point mutation of Thr58 to alanine attenuated silymarin-mediated inhibition of the cell growth. The results suggest that silymarin induces the cell growth arrest through c-Myc proteasomal degradation via ERK1/2, p38 and $GSK3{\beta}-dependent$ Thr58 phosphorylation.

• 한국전기전자재료학회논문지
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• 제36권1호
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• pp.16-22
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• 2023

In a solar cell, degradation refers to the decrease in performance parameters caused by defects originated due to various causes. During the fabrication process of solar cells, degradation is generally related to the processes such as passivation or firing. There exist sources of many types of degradation; however, the exact cause of Light and elevated Temperature Induced Degradation (LeTID) is yet to be determined. It is reported that the degradation and the regeneration occur due to the recombination of hydrogen and an arbitrary substance. In this paper, we report the deposition of Al₂O₃ and SiN_X on silicon wafers used in the Passivated Emitter and Rear Contact (PERC) solar structure and its degradation pattern. A higher degradation rate was observed in the sample with single layer of Al₂O₃ only, which indicates that the degradation is affected by the presence or the absence of a passivation thin film. In order to alleviate the degradation, optimization of different steps should be carried out in consideration of degradation in the solar cell fabrication process.

• 보존과학회지
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• 제2권2호
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• pp.15-24
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• 1993

To understand the morphological change of ancient woods, samples classified by cell type, burial environment and species were collected and observed using microscopy. Decay of wood by cell type could classified into two types. First, degraded secondary wall was formed granular residues in $S_2$ layer and was remained $S_3$ layer and compound middle lamella. Second, the cell wall was slightly degraded and cracked in secondary wall. A gradual thinning of cell wall was occured. The compound middle lamella was separated from secondary wall. The resistance of degradation is increased at vessels, parenchyma, and tracheid and wood fiber in the order named. The type of degradation by species could be classified into four types. Overall degradation type; the degradation of cell wall is usually heavy and the extent of degradation Varies by part of the same sample. Partial degradation type ; this type shows severely different decay type by part of the sample. Nondegraded cells were mixed with degraded cells on the same sample. Erose degradation type ; thinning of the cell wall was occoured and the degradation type was different by part. Slight degradation types ; secondary wall was slightly degraded, cracked and separated from compound middle lamella. Considering different type of burial environment, dry wood was similiar to sound wood and slightly decayed. Waterlogged and peat burial wood was heavilydecayed. Between species of under the same environment, decay type and extent were diferentiated from each other.

• 한국식품저장유통학회지
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• 제3권1호
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• pp.93-104
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• 1996

The cell wall components of fruit include cellulose. hemicellulose, pectin, glycoprotein etc., and the cell wall composition differs according to the kind of fruit. Fruit softening occurs as a result of a change in the cell wall polysaccharides : the middle lamella which links primary cell walls is composed of pectin. and primary cell walls are decomposed by a solution of middle lamella caused due to a result of pectin degradation by pectin degrading enzymes during ripening and softening, During fruit ripening and softening, contents of arabinose and galactose among non-cellulosic neutral sugars are notably decreased, and this occurs as a result of the degradation of pectin during fruit repening and softening since they are side-chained with pectin in the form of arabinogalactan and galactan Enzymes involved in the degradation of the cell wall include polygalacturonase, cellulose, pectinmethylesterase, glycosidase, etc., and various studies have been done on the change in enzyme activities during the ripening and softning of fruit. Among cell wall-degrading enzymes, polygalacturonase has the greatest effect on fruit softening, and its activity Increases during the maturating and softening of fruit. This softening leads to the textural change of fruit as a result of the degradation of cell wall polysaccharides by a cell wall degrading enzyme which exists in fruit.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2000년도 하계학술대회 논문집
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• pp.177-180
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• 2000

We studied the degradation of EVA for the protection of solar cell by UV-rays irradiation. We investigated the reduction of electrical efficiency, photo transmmitance and degradation of EVA by UV-rays irradiation. We utilized the UV irradiation equiped with fluorescent 313nm UV lamp and radiated for 400 hours. For the chemial analysis, we used the UV-vis spectrometer, XPS and examined the degradation mechanism by UV irradiation. It is found that the discolored phenomena, the decrease of photo transmmitance and oxidation reaction is occured by UV irradiation on the EVA sample for the protection of solar cell.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2009년도 추계학술대회 논문집
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• pp.132-132
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• 2009

To achieve the commercialization of PEM fuel cell, the durability problem must be solved. Recently, many researchers have focused on this durability problem and degradation studies about membrane and electrode have been reported. But durability characteristics of gas diffusion layer is not much reported yet. Durability of GDL is very important to maintain the performance of PEM fuel cell because the main function of GDL is a path of fuel and water and the GDL degradation causes the loss of the GDL function. In this study, the degradation of GDL, especially, the mechanical degradation process was investigated with the leaching test. The effect of water dissolution was observed through the test and the amount of GDL degradation was measured with various measurement methods such as weight measurement, static contact angle measurement, scanning electron microscope. After 2,000 hours test, the GDL showed structural damage and loss of hydrophobicity.

• 한국미생물·생명공학회지
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• 제22권2호
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• pp.203-209
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• 1994

The bacterial strain which utilizes phenol and degrade TCE was isolated from an industrial waste site. The bacterial strain was named as T5-7 and identified as an Acinetobacter species. After phenol-induction, the strain T5-7 removed TCE efficiently without cell growth. So, it seems that TCE degradation was not related to cell growth. TCE degradation increased when initial cell concentrations of phenol-grown T5-7 were high. In the presence of phenol, initial degradation of TCE was delayed but total amount of degradation was not affected at final stage. The strain cultured in 0.1% yeast extract did not degrade TCE, which indicates that phenol induction was essential to the TCE degradation.

• 한국동물학회지
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• 제32권2호
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• pp.134-141
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• 1989

본 연구는 온열처리에 의한 세포치사의 mechqnism을 밝히기 위해서 heat sensitizer인 low pH와 heat protector인 glycerol을 이용하여 cell lethlity와 단백질의 분해 kinetics를 검토한 것이다. 41-45도씨의 온열처리 중에서 41도씨를 제외한 전 온도범위에서 sensitizer와 protector의 효과가 뚜렷이 나타났으며, protector이 효과는 cell lethality와 단백질분해 모두에서 sensitizer의 효과에 비해서 현저히 나타나서 sensitizer와 protector의 작용기작은 서로 다를 것으로 생각되었다. 즉, 43-44도씨에서 cell inactivation energy는 정상, low pH, glycerol 상태에서 각각 239, 190, 317 kcal/mole의 값을 보였다. 단백질분해 kinetics의 경우에도 대체적인 경향성은 cell inactivation kinetics와 유사하였으나, 직접적인 연관성은 발견할 수 없었다. 이와 같은 결과로 미루어 볼 때, cell lethality와 단백질 분해의 mechanism 사이에 직접적인 관계는 없고, 주로 막단백질로 추정되는 단백질의 inactivation에 의한 세포내 환경의 변화에 의해서 2차적으로 세포치사가 일어나는 것으로 추정할 수 있으며, 정확한 mechanism을 밝히기 위해서는 DNA polymerase를 비롯한 몇가지 가능한 표적에 대한 연구가 이루어져야 할 것으로 사료된다.

• International journal of advanced smart convergence
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• 제5권2호
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• pp.18-23
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• 2016

Cell walls of microalgae consist of a polysaccharide and glycoprotein matrix providing the cells with a formidable defense against its environment. Anaerobic digestion (AD) of microalgae is primarily inhibited by the chemical composition of their cell walls containing biopolymers able to resist bacterial degradation. Adoption of pre-treatments such as thermal, thermal hydrolysis, ultrasound and enzymatic hydrolysis have the potential to remove these inhibitory compounds and enhance biogas yields by degrading the cell wall, and releasing the intracellular algogenic organic matter (AOM). This paper preproposal stage investigated the effect of different pre-treatments on microalgae cell wall, and their impact on the quantity of soluble biomass released in the media and thus on the digestion process yields. This Paper present optimum approach to degradation of the cell wall by ultra-sonication with practical design specification parameter for ultrasound based pretreatment system. As a result of this paper presents, a microalgae system in a wastewater treatment flowsheet for residual nutrient uptake can be justified by processing the waste biomass for energy recovery. As a conclusion on this result, Low energy harvesting technologies and pre-treatment of the algal biomass are required to improve the overall energy balance of this integrated system.

• 한국수소및신에너지학회논문집
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• 제25권3호
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• pp.311-318
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• 2014

Performance degradation of a battery in 20 kWh energy storage system (ESS) under various operating conditions was studied. And energy saving of the ESS was also monitored by connecting with 20 kW photovoltaic (PV). PV-connected ESS saved 5~7% of energy consumption in 2013 compared to that without such system in 2012. As charge-discharge cycle increased, capacity decreased and the performance degradation was glaringly obvious after 40 cycles. And as charge and discharge rate increased, the performance degradation was more serious. After 50 charge-discharge cycles, a lot of degraded product was deposited on the surface of anode and cathode electrodes, and the cathode side was more contaminated. Therefore, in order to maintain the cell performance, it was more important to protect the degradation of the cathode side.