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        검색결과 23

        2.
        2024.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        최근 전기차 시장의 확장으로 배터리 산업이 급격히 성장함에 따라 폐배터리 리사이클링 기술 개발의 필요성이 증가하고 있다. 폐배터리 리사이클링 기술은 배터리 산업에 핵심적인 리튬, 코발트, 니켈 등 희소금속의 공급을 안정화하고 환경 및 인간의 건강에 미치는 영향을 경감할 수 있다. 본 총설에서는 금속 회수 기술의 배경이 되는 이론적 원리와 현재 상 용되고 있는 금속 회수 공정을 소개하고자 한다. 또한, 기존 공정의 문제점을 개선하려는 연구 및 기술 개발 동향을 서술하여 리사이클링 기술이 나아가야 할 방향을 소개하고자 한다.
        4,000원
        3.
        2023.05 구독 인증기관·개인회원 무료
        The organic complexing agents such as ethylenediaminetetraacetic acid (EDTA), nitrilotriacetic acid (NTA), and isosaccharinic acid (ISA) can enhance the radionuclides’ solubility and have the potential to induce the acceleration of radionuclides’ mobility to a far-field from the radioactive waste repository. Hence, it is essential to evaluate the effect of organic complexing agents on radionuclide solubility through experimental analysis under similar conditions to those at the radioactive waste disposal site. In this study, five radionuclides (cesium, cobalt, strontium, iodine, and uranium) and three organic complexing agents (EDTA, NTA, and ISA) were selected as model substances. To simulate environmental conditions, the groundwater was collected near the repository and applied for solubility experiments. The solubility experiments were carried out under various ranges of pHs (7, 9, 11, and 13), temperatures (10°C, 20°C, and 40°C), and concentrations of organic complexing agents (0, 10-5, 10-4, 10-3, and 10-2 M). Experimental results showed that the presence of organic complexing agents significantly increased the solubility of the radionuclides. Cobalt and strontium had high solubility enhancement factors, even at low concentrations of organic complexing agents. We also developed a support vector machine (SVM) model using some of the experimental data and validated it using the rest of the solubility data. The root mean square error (RMSE) in the training and validation sets was 0.012 and 0.016, respectively. The SVM model allowed us to estimate the solubility value under untested conditions (e.g., pH 12, temperature 30°C, ISA 5×10-4 M). Therefore, our experimental solubility data and the SVM model can be used to predict radionuclide solubility and solubility enhancement by organic complexing agents under various conditions.
        4.
        2016.10 구독 인증기관·개인회원 무료
        The α-Gal epitope (Galα1,3Galα1,4GlcNAc-R) is responsible for hyperacute rejection (HAR) during transgenic pig-to-non-human primate xenotransplantation. To overcome HAR after xenografts, it is essential for the inactivation of α1,3Galactosyltransferase (GT) gene by the homozygotic knocked out of GT-/- and the isoglobotrihexosylceramide synthase (iGb3s-/-). This study was performed to investigate the generation and characterization of the α1,3GT-MCP/-MCP+iGb3-/- transgenic cells. Ear fibroblast cells from the GT-MCP/-MCP pig were cultured and used to positive control. For iGb3s knock out, the Cas9-GFP-iGb3s vector was transfected into the GT-MCP/-MCP cells. The Cas9-GFP-iGb3s transfected cells were sorted and sequenced for the selection of GT-MCP/-MCP+ iGb3s-/- cells. Among the three sorted cell lines, one transgenic cell line was homozygously deleted 3 bases and 10 bases in each chromosome, respectively. To characterize an expression of α-Gal epitope, a wild type and the transgenic cells were measured by FACS Aria using BS-IB4 lectin antibody. The expression of α-Gal epitope in GT-MCP/-MCP cells (<0.01 %) were significantly down-regulated to the range of wild type (99.4 %) fibroblast cells (p<0.05). To analyze the function of iGb3s, α -Gal epitope expressions were measured for the GT-MCP/-MCP, GT-MCP/-MCP+iGb3s-/+, and GT-MCP/-MCP+iGb3s-/-. The range was 95.8%, 94.2%, and 75.8%, respectively. Interestingly, there was a negative range (16.2%) of α-Gal epitope -/- section in GT-MCP/-MCP+iGb3s-/-, compared to 2.74% of GT-MCP/-MCP+iGb3s-/+ and 1.4% of WT, respectively. Our results demonstrated that iGb3s-/-combined with GT-/- had a function to inhibit α-Gal epitope expression in pig cells. Further studies are needed to evaluate the functions of double gene knock out to minimize a HAR response after xenotransplantation.
        5.
        2016.10 구독 인증기관·개인회원 무료
        The α-Gal epitope (Galα1,3Galα1,4GlcNAc-R) is responsible for hyperacute rejection (HAR) during transgenic pig-to-non-human primate xenotransplantation. There are genes related to the expression of α-Gal epitope such as α1,3Galactosyltransferase gene (GT-/-) and the isoglobotrihexosylceramide synthase (iGb3s-/-). This study was performed to investigate the expression of α-Gal epitope in the skin derived from GT-/- transgenic pig. The skin (7/1000 inches) was obtained by dermatome (Zimmer® Electric Dermatome) from one month old of wildtype (WT) and GT-/- piglets, respectively. The skins were fixed, dehydrated, cleaned, and embedded. To analyze the expression of α-Gal epitope, the paraffin section of WT and GT-/- were stained with BS-IB4 lectin and isoglobotrihexosylceramide synthase antibody. There was a strong BS-IB4 lectin signal in the skin of WT, but not detected in GT-/-. However, the iGb3s positive signals were stained in the skin of both WT and GT-/-. Taken together, it can be postulated that the knocked out of GT gene may not enough to inhibit the expression of α-Gal epitope. Further studies are needed to evaluate the functions of the double knock out of GT and iGb3s on the expression of α-Gal epitope.
        6.
        2015.12 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        Nd-Fe-B permanent magnets have been used in a wide variety of applications because of their high magnetic flux density. So, demand for neodymium has been increasing in worldwide. In this study, an electrowinning process was performed in LiF-NdF3-Nd2O3 high temperature molten salts. However, a corrosion resistant material for use in the molten salt must be found for stable operation because of the harsh corrosion environment of the electrowinning process. Therefore, for this paper, boron nitride(BN), aluminum nitride(AlN), and silicon nitride(Si3N4) were selected as protective and structural materials in the high temperature electrolyte. To investigate the characteristics of BN, AlN, and Si3N4, in molten salts, materials were immersed in the molten salts for 24, 72, 120, and 192 hours. Also, surface condition and stability were investigated by SEM and EDS and corrosion products were calculated by HSC chemistry. As a result, among BN, AlN, and Si3N4, AlN was found to show the best protective material properties.
        4,000원
        7.
        2014.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        새로 조성된 간척농지의 토양개량을 위하여 새만금간척지에서 2007년부터 2011년까지 4년 동안 녹비작물 (여름철 : 세스바니아, 제주재래피, 수수×수단그라스, 겨울철 : 귀리, 호밀, 보리) 재배 및 시용이 토양이화학성에 미치는 영향을 조사하여얻은 결과는 다음과 같다.1. 녹비작물의 바이오매스 생산량은 평균 9.7~15.0ton/ha이었으며, 이 중에서 수수×수단그라스의 생산량이 가장 많았다.2. 녹비작물의 재배와 시용으로 토양유기물 함량이 1.3에서6.0g/kg로 매년 평균 1.2g/kg씩 증가하였다.3. 녹비작물의 재배와 토양환원에 의해 토양의 용적밀도가1.44에서 1.24Mg/m3로 감소하였다.4. 수수×수단그라스와 호밀의 이어짓기가 토양 용적밀도 감소에 가장 효과적이었고, 세스바니아 재배는 토양 질소함량 증가에 가장 효율적이었다.이상의 결과로 미루어 볼 때 간척지에서의 녹비작물 재배및 시용은 토양의 비옥도 요인을 일부 개선시킴으로써 간척농지 개량에 기여할 수 있을 것으로 기대된다. 앞으로 신간척지에서의 유기물과 관련된 다각적인 연구가 필요할 것으로 생각된다.
        4,000원
        8.
        2013.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Spermatogonial stem cells (SSCs) developed into sperms through spermatogenesis have been utilized as a useful tool in the field of regenerative medicine and infertility. However, a small number of highly qualified SSCs are resided in the seminiferous tubule of testis, resulted in developing effective in-vitro culture system of SSCs for solving simultaneously quantitative and qualitative problems. Presently, SSCs can be enriched on testicular stromal cells (TSCs), but there are no systematic researches about TSC culture. Therefore, we tried to optimize culture condition of TSCs derived from mouse with different strains. For these, proliferation and viability were measured and compared by culturing ICR outbred or DBA/2 inbred mouse-derived TSCs at 35 or 37℃. In case of ICR strain, primary TSCs cultured at 37℃ showed significantly higher proliferation and viability than those at 35℃ and significant increase of proliferation and viability in sub-passaged TSCs was detected in the 35℃ culture condition. Moreover, sub-passage of primary TSCs at 35℃ induced no significant effects on proliferation and viability. In contrast, in case of DBA/2 strain, significantly improved proliferation were detected in the primary TSCs cultured at 35℃, which showed no significant difference in the viability, compared to those at 37℃. Furthermore, sub-passaged TSCs cultured at 37℃ showed no significant differences in proliferation and viability, compared to those at 35℃. However, with significant decrease of proliferation induced by sub-passage of primary TSCs at 35℃, no significant effects on proliferation and viability were resulted from sub-passage of primary TSCs at 37℃. From these results, culture temperature of primary TSCs derived from outbred and inbred strain of mouse could be separately optimized in primary culture and subculture.
        4,000원
        9.
        2013.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        We have previously investigated the proteome changes of rice leaves under heat stress (Lee et al. in Proteomics 2007a, 7:3369- 3383), wherein a group of antioxidant proteins and heat shock proteins (HSPs) were found to be regulated differently. The present study focuses on the biochemical changes and gene expression profiles of heat shock protein and antioxidant genes in rice leaves in response to heat stress (42°C) during a wide range of exposure times. The results show that hydrogen peroxide and proline contents increased significantly, suggesting an oxidative burst and osmotic imbalance under heat stress. The mRNA levels of chaperone 60, HSP70, HSP100, chloroplastic HSP26, and mitochondrial small HSP responded rapidly and showed maximum expression after 0.5 or 2 h under heat stress. Transcript levels of ascorbate peroxidase (APX), dehydroascorbate reductase (DHAR) and Cu-Zn superoxide dismutase (Cu-Zn SOD) showed a rapid and marked accumulation upon heat stress. While prolonged exposure to heat stress resulted in increased transcript levels of monodehydroascorbate reductase, peroxidase, glyoxalase 1, glutathione reductase, thioredoxin peroxidase, 2-Cysteine peroxiredoxin, and nucleoside diphosphate kinase 1, while the transcription of catalase was suppressed. Consistent with their changes in gene expression, the enzyme activities of APX and DHAR also increased significantly following exposure to heat stress. These results suggest that oxidative stress is usually caused by heat stress, and plants apply complex HSP- and antioxidant-mediated defense mechanisms to cope with heat stress.
        4,000원
        10.
        2012.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구는 농업유전자원센터에 보존되어있는 불가리아 재래종 고추 유전자원 61 점을 대상으로 농업형질을 조사하고, 22개의 분자마커(SSR marker)를 이용하여 불가리아 재래종 고추 유전자원의 유전적 다양성 및 집단분석을 통하여, 자원보존 및 효율적인 작물 육종을 위한 기초정보를 제공하고자 본실험을 수행하였으며 결과는 다음과 같다. 1. 파종 후 발아까지 소요일수는 최소 11일에서 최대 26 일,평균 16.9 일이었고 개화 소요일수는 최소 48일, 최대 65일, 평균 56.9일이었으며 성숙까지의 소요일수는 최소 73일, 최대 98일, 평균 90.7일이었다. 2. 농업형질의 특성을 바탕으로 PCA 분석을 이용하여 불가리아 고추의 다양성을 분석한 결과, 파종 후 개화까지의 소요일수에 따라 조생종, 중생종, 만생종 3개의 그룹으로 나눌 수있었다. 3. 61점의 고추자원에 대하여 22개 SSR 마커에 의해 나타난 대립유전자 (allele)수는 총 82개였다. 마커당 평균 allele수는 3.7 개였고, allele 수의 범위는 2개에서 5개로 확인되었다. 유전적 다양성을 나타내는 PIC 값의 범위는 0.061-0.636이었으며 평균 PIC 값은 0.349로 확인되었다. 4. 분자마커(SSR)를 이용하여 UPGMA, PCoA, STUCTURE 분석을 통한 고추의 다양성 및 집단 구조를 분석한 결과, 3개의 그룹으로 나뉘어졌다. 결론적으로, 농업형질 특성을 바탕으로 한 불가리아 재래종고추의 다양성과 분자학적 특성을 이용한 다양성 결과와는 차이가 있었다.
        4,000원
        12.
        2013.07 서비스 종료(열람 제한)
        Rice (Oryza sativa) is the most important staple food of over half the world’s population. This study was conducted to evaluate the possible impact of transgenic rice cultivation on the soil microbial community. Microorganisms were isolated from the rhizosphere of GM and non-GM rice cultivation soils. Microbial community was identified based on the culture-dependent and molecular biology methods. The total numbers of bacteria, fungi, and actinomycete in the rhizosphere soils cultivated with GM and non-GM rice were similar to each other, and there was no significant difference between GM and non-GM rice. Dominant bacterial phyla in the rhizosphere soils cultivated with GM and non-GM rice were Actinobacteria, Firmicutes, and Proteobacteria. The microbial communities in GM and non-GM rice cultivated soils were characterized using the denaturing gradient gel electrophoresis (DGGE). The DGGE profiles showed similar patterns, but didn’t show significant difference to each other. DNAs were isolated from soils cultivating GM and non-GM rice and analyzed for persistence of inserted gene in the soil by using PCR. The PCR analysis revealed that there were no amplified protox gene in soil DNA. These data suggest that transgenic rice does not have a significant impact on soil microbial communities, although continued research may be necessary.
        13.
        2012.12 KCI 등재 서비스 종료(열람 제한)
        The objective of this study was to analyze the genetic diversity using SSR marker and investigate the fatty acid composition of perilla (P. frutescens var. frutescens) germplasm. Genetic diversity among 95 accessions, which consisted of 29 weedy types and 66 landrace accessions, was evaluated based on 12 SSR markers carrying 91 alleles. The mean values of observed (HO) and expected heterozygosities (HE) were 0.574 and 0.640, respectively, indicating a considerable amount of polymorphism within this collection. A genetic distance-based phylogeny grouped into two distinct groups, which were the landrace, moderate and weedy type, genetic distance (GD) value was 0.609. The physicochemical traits about crude oil contents and fatty acid compositions were analyzed using GC. Among tested germplasm, the total average oil contents (%) showed a range from 28.57 to 49.67 %. Five fatty acids and their contents in the crude oils are as follows: α-linolenic acid (41.12%-51.81%), linoleic acid (15.38%-16.43%), oleic acid (18.93%-27.28%), stearic acid (2.56%-4.01%), and palmitic acid (7.38%-10.77%). The average oil content of wild types was lower than landrace, and the oil content of middle genotype accessions was higher than other germplasm, but no significant variation between landrace and wild types was shown. Nevertheless, IT117174, landrace of Korea, was highest in crude oil content (47.11%) and linolenic acid composition (64.58%) among the used germplasm. These traits of the selected accessions will be helped for new functional plant breeding in perilla crop.
        14.
        2012.07 서비스 종료(열람 제한)
        Tall fescue (Festuca arundinacea Schreb.) is an important cool season forage plant that is not well suited to extreme heat, salts, or heavy metals. To develop transgenic tall fescue plants with enhanced tolerance to abiotic stress, we introduced a MsHsp23 gene expression vector construct through Agrobacterium-mediated transformation. Integration and expression of the transgene were confirmed by PCR, northern blot, and western blot analyses. Under normal growth conditions, there was no significant difference in the growth of the transgenic plants and the non-transgenic controls. However, when exposed to various stresses such as salt or arsenic, transgenic plants showed a significantly lower accumulation of hydrogen peroxide and thiobarbituric acid reactive substances than control plants. We speculate that the high levels of MsHsp23 proteins in the transgenic plants protect leaves from oxidative damage through chaperon and antioxidant activities. These results suggest that MsHsp23 confers abiotic stress tolerance in transgenic tall fescue and may be useful in developing stress tolerance in other crops. Compared with traditional plant breeding, genetic engineering provides a relatively fast and precise means of achieving improved stress tolerance of forage crops. Development of forage crops that are more tolerant to various abiotic stresses could lead to the use of more new lands for cultivation.
        15.
        2012.07 서비스 종료(열람 제한)
        The amount of genetic variability of a species is essential for its survival and adaptation in different environments, and studies of genetic diversity using molecular markers are necessary to understand the genetic structure of a population and to orientate effective strategies of germplasm conservation. The aim of current study was to determine the SSR markers that can be used rapidly and reliably to evaluated the pepper of Bulgaria landraces, and applied the markers to assement of introduce genetic diversity of the pepper germplasm. We used 22 polymorphic microsatellite markers to analysis of genetic diversity within 61 pepper collection of Bulgaria landraces germplasm, all SSR primers pairs produced 80 polymorphic and reproducible amplification fragments. An average value of polymorphic information contents (PIC) were 0.334 with a range of 0.061 to 0.63. The mean values of observed (HO) and expected heterozygosity (HE) were 0.383 and 0.154, respectively, indicating a considerable amount of polymorphism within this collection. A genetic distance-based phylogeny grouped into three distinct groups, which was the landrace, moderate and wilde type, genetic distance (GD) value was 0.540. An average day of flowering time was 53 days with a range of 45 to 60 days. The everage od fruit length and width were 9.38cm with a range 2.1 to 23.6cm, and 3.51cm with a range 0.6 to 8.9cm, respectively. Molecular data were complemented with morphological measurements according to the descriptor list for the pepper collection of Bulgaria landraces germplasm.
        16.
        2008.09 KCI 등재 서비스 종료(열람 제한)
        Due to the rapid changes in world trade and shipping environment, today's ports face ever-increasing competition, from adjacent competing ports. To this reason, port service quality has been recognized as an important strategy to take competitive advantage for those competition. In general, service quality has effect on customer loyalty, and customer loyalty is the resource to sustain competitive advantage which service providers or service producers. By improving customer loyalty, companies can get more benefits and added value. However, this causality qf port service quality has not been clearly identified. Thus, various empirical studies in relation to port service quality are needed. The aim of this study is to analyze the effect of perceived port service quality on customer satisfaction and loyalty. To achieve this aim, we established 8 hypotheses based on SERVPERF in order to test correlations of 5 dimensions of port service, port service quality, customer satisfaction, and customer loyalty. From the result of the hypothesis testing, we found that customer satisfaction and port service quality do not affect customer loyalty in spite of high effect of port service on customer satisfaction.
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