• Korean journal of food and cookery science
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• v.20 no.3
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• pp.256-264
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• 2004

The effects of irradiation on the functional and structural characteristics of soy protein isolates were studied. Soymilk was irradiated at 1, 5, and l0kGy, after which soy protein isolates were prepared. The functional properties of soy protein isolates were examined including solubility, emulsion capacity and stability, foam capacity and stability, structural properties as represented by SDS-PAGE pattern, and secondary and tertiary structures. The solubility and emulsion capacity were increased by radiation treatment at 1kGy however the values were adversely affected again as dosage was increased above 5kGy. As irradiation dosage increased, an increase of foaming capacity at 1kGy and a decreasing turnover afterwards were also noted in foaming capacity, although the differences were not statistically significant. The SDS-PAGE pattern showed fragmentation and aggregation of protein molecules as affected by irradiation in proportion to the dosage increase. The results of CD and fluorescence spectroscopy revealed increased aperiodic structure contents with the dosage increase. It was assumed that irradiation dosagefrom 5 to l0kGy could initiate minimal denaturation of protein in various foods compared to general heat treatment.

• Proceedings of the Zoological Society Korea Conference
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• 1998.10b
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• pp.360-360
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• 1998

C11, a chloride-containing VK3 analog, acts as a mediator of programmed cell death in SK-Hep-1 cell lines, but its molecular mechanisms linked to cell death are not understood. In this study, we investigated the expression of p21 gene and its relationship to apoptosis induced by C11. In SK -hep-1 cells, the addition of C11 resulted in time-dependent growth suppression and DNA fragmentation characteristics of apoptosis. p21 protein was induced during this process, while the protein level of p53 was not changed at the same condition. This apoptotic cell death with p21 induction was also observed in the Hep3B cells lacking functional p53 after treatment of C11. These results suggest that C11-induced apoptosis is associated with up-regulation of p21 protein in p53-independent pathway. Next, in order to confirm whether the p53-independent p21 induction is required for C11-induced apoptosis, we introduced the p21 gene into Hep3B. Overexpression of p21 did not affect the expression of the bcl-2 gene, but DNA fragmentation and PARa cleavage were significantly increased. These data indicate that p21 is involved in C11-induced apoptosis. Although Bcl-2 has been implicated to interfere with an essential signaling molecule involved in the apoptosis pathway, its molecular mechanism and target molecule are poorly understood. To determine the effects of bcl-2 overexpression on apoptosis and to investigate whether BcI-2 interfers with the p53-independent p21 pathway, we transfected the bcl-2 expression vector into SK - Hep-1 cels. Overexpression of Bcl-2 prevented C11-induced apoptosis. Taken together, C11-induced apoptosis is regulated by p52-independent p21 pathway and bcl-2 may inhibit functional activity of p21, therebe may inhibit the C11-induced apoptosis.ptosis.

• Journal of Forest and Environmental Science
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• v.40 no.3
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• pp.241-249
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• 2024

Human development activities have led to changes in land cover, resulting in the loss of green spaces such as forests and agricultural lands. This loss accompanies issues of habitat reduction and hindrance to wildlife movement. Due to the decrease in urban green spaces, urban green connectivity is reducing. This study aims to analyze changes in green space connectivity through structural and functional changes in green spaces caused by land cover changes. Quantitative analysis of landscape patterns using landscape indices through Fragstats model was employed to analyze the structural changes in green spaces. This study used seven landscape indices to assess the fragmentation and isolation of green spaces. The analysis was focused on changes occurring in agricultural lands, forests, and grasslands within Yongin-si, South Korea, over 20 years from 1989 to 2019. Among the landscape indices for forests, PLAND showed a decrease of approximately 8.2% from 1989 to 2009, while NP exhibited a decline of about 2,025 patches. This indicates both a reduction in the total area of green spaces in Yongin-si. Also, we analyzed functional changes based on landscape index variations in forest land within the study area between 2009 and 2019, and least-cost path (LCP) analysis was conducted using Linkage Mapper. Results yielded 18 and 16 links for 2009 and 2019, respectively, with 12 common links. It was observed that five links showed a slight decrease, indicating partial deletions of links, contributing to the fragmentation and discontinuity of forests.

• Journal of the Korean Wood Science and Technology
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• v.47 no.4
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• pp.442-450
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• 2019

Despite its potential as a renewable source for fuels and chemicals, lignin valorization still faces technical challenges in many aspects. Overcoming such challenges associated with the chemical recalcitrance of lignin can provide many opportunities to innovate existing and emerging biorefineries. In this work, we leveraged a biomass genetic engineering technology to produce phenolic aldehyde-rich lignin structure via downregulation of cinnamyl alcohol dehydrogenase (CAD). The structurally altered lignin obtained from the Arabidopsis thaliana CAD mutant was pyrolyzed to understand the effect of structural alteration on thermal behavior of lignin. The pyrolysis was conducted at 400 and $500^{\circ}C$ using an analytical pyrolyzer connected with GC/MS and the products were systematically analyzed. The results indicate that aldehyde-rich lignin undergoes fragmentation reaction during pyrolysis forming a considerable amount of C6 units. Also, it was speculated that highly reactive phenolic aldehydes facilitate secondary repolymerization reaction as described by the lower yield of overall phenolic compounds compared to wild type (WT) lignin. Quantum mechanical calculation clearly shows the higher electrophilicity of transgenic lignin than that of WT, which could promote both fragmentation and recondensation reactions. This work provides mechanistic insights toward biomass genetic engineering and its application to the pyrolysis allowing to establish sustainable biorefinery in the future.

• Journal of Environmental Impact Assessment
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• v.21 no.3
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• pp.391-407
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• 2012

The loss of connectivity and fragmentation of forest landscapes are seriously hindering dispersal of many forest-dwelling species, which may be critical for their viability and conservation by decreasing habitat area and increasing distance among habitats. For understanding their environmental impacts, numerous spatial models exist to measure landscape connectivity. However, general relationships between functional connectivity and landscape structure are lacking, there is a need to develop landscape metrics that more accurately measure landscape connectivity in whole landscape and individual patches. We reviewed functional and structural definition of landscape connectivity, explained their mathematical connotations, and applied representative 13 indices in 3 districts of Seoul having fragmented forest patches with tits, the threshold distance was applied 500m by considering the dispersal of tits. Results of correlation and principal component analysis showed that connectivity indices could be divided by measurement methods whether they contain the area attribute with distance or not. Betweenness centrality(BC), a representative index measuring distance and distribution among patches, appreciated highly stepping stone forest patches, and difference of probability of connectivity(dPC), an index measuring including area information, estimated integrated connectivity of patches. Therefore, for evaluating landscape connectivity, it is need to consider not only general information of a region and species' characteristics but also various measuring methods of landscape connectivity.

• Elastomers and Composites
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• v.55 no.3
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• pp.167-175
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• 2020

Various studies have been conducted to improve silica dispersion of silica filled tire tread compounds; among them, silica wet masterbatch (WMB) technology is known to be suitable for manufacturing silica filled compounds that have high silica content and high dispersibility. Till now, the WMB study is focused on the natural rubber (NR) or emulsion styrene-butadiene rubber (ESBR) that does not have a silica-affinity functional group, and a study of NR or ESBR having a silica-affinity functional group is still not well known. Unlike the dry masterbatch technology, the WMB technology can solve the problems associated with the high Mooney viscosity when applied to silica-friendly rubber. However, a coagulant suitable for each functional group has not yet been determined. Therefore, in this study, different coagulant applied silica WMB was prepared by applying calcium chloride, sulfuric acid, acetic acid, and propionic acid by using a carboxyl group functionalized reversible addition fragmentation chain transfer ESBR. The evaluation of the WMB compounds revealed that the calcium chloride added WMB compound showed excellent silica dispersion, abrasion resistance, and rolling resistance.

• Toxicological Research
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• v.21 no.4
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• pp.303-307
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• 2005

Nanomaterials, which ranges in size from 1 to 100 nm, have been used to create uqnique devices at the nanoscale level possessing novel physical and chemical functional properties. However, the toxicities of nanomaterials have not been fully tested and the risk of nanomaterials is emerging issues in these days. In this study, the cytotoxicity of copper nanoparticles was tested in cultured human bronchial epithelial cells. As a results, copper nanoparticles showed cytotoxicity similar with cupric ion and the apoptotic mechanisms of DNA fragmentation and caspase-3 activation were involved. Induction of heme oxygenase-1 and thioredoxin reductase by copper nanoparticles indicated that cytotoxicity of copper nanoparticles is likely to be mediated through oxidative stress.

• Bulletin of the Korean Chemical Society
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• v.27 no.8
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• pp.1099-1114
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• 2006

Our studies in the area of single electron transfer (SET) photochemistry have led to the discovery of efficient processes, in which regioselective formation of carbon-centered radicals takes place by nucleophile assisted desilylation of $\alpha$-trialkylsilyl substituted ether, thioether, amine and amide centered cation radicals. The rates of bimolecular desilylation of the intermediate cation radicals exceed those of other cation radical $\alpha$-fragmentation processes (e.g.,-deprotonation). This sereves as the basis for the design of highly regioselective, SET-induced photomacrocyclization reactions of polyether, polythioether, polyamide, and polypeptide linked phthalimides. Photocyclization reactions of trimethylsilyl-terminated substrates in these families are unique in that they produce polyfunctionalized macrocyclic substances in a highly efficient and regioselective manner. In addition, our studies in this area have led to important information about the factors that govern chemical and quantum efficiencies that should be applicable to a wide variety of redox processes promoted by SET from substrates containing more than one electron donor site.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2014.11a
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• pp.286-288
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• 2014

This study deals with the catalyst free radio frequency plasma assisted polymerization of ethylene glycol using nitrogen as reactive gas to modify the surface chemistry and morphology. The deposited film was characterized through various analysis techniques i.e. surface profilometry, Forier transform infrared spectroscopy, water contact angle and UV-visible spectroscopy to analyze film thickness, chemical structure, surface energy and optical properties respectively. The surface topography was analyzed by Atomic force microscopy. It was observed that the ethylene oxide behaviour and optical transmittance of the film were reduced with the introduction of nitrogen gas due to higher fragmentation of monomer. However the hydrophilic behavior of the film improved due to formation of new water loving functional groups suitable for biomedical applications.

• The Korean Journal of Physiology and Pharmacology
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• v.6 no.5
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• pp.235-239
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• 2002

It has been reported that lovastatin induced cell death and suppressed proliferation in various cell lines. In this study, we examined whether the cytotoxic effects of lovastatin could be prevented by Bcl-2 or $Bcl-_{XL}$ in C6 glial cells. Overexpression of human Bcl-2 or $Bcl-_{XL}$ prevented lovastatin $(25{\mu}M)-induced$ changes such as DNA fragmentation, chromatin condensation, disruption of cell membrane, and cleavage of poly (ADP-ribose) polymerase. Lovastatin-induced inhibition of cell proliferation was unaffected by Bcl-2 or $Bcl-_{XL}$ overexpression. These results suggest that Bcl-2 and $Bcl-_{XL}$ can prevent lovastatin-induced apoptosis in C6 glial cells, though the inhibition of proliferation remains unaffected by these proteins.