• Plant Breeding and Biotechnology
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• 제6권4호
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• pp.321-336
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• 2018

Sesame (Sesamum indicum L.) is an important oilseed crop grown in tropical and subtropical areas. The objective of this study was to investigate the genetic relationships among 129 sesame landraces and cultivars using simple sequence repeat (SSR) markers. Out of 70 SSRs, 23 were found to be informative and produced 157 alleles. The number of alleles per locus ranged from 3 - 14, whereas polymorphic information content ranged from 0.33 - 0.86. A distance-based phylogenetic analysis revealed two major and six minor clusters. The population structure analysis using a Bayesian model-based program in STRUCTURE 2.3.4 divided 129 sesame accessions into three major populations (K = 3). Based on pairwise comparison estimates, Pop1 was observed to be genetically close to Pop2 with $F_{ST}$ value of 0.15, while Pop2 and Pop3 were genetically closest with $F_{ST}$ value of 0.08. Analysis of molecular variance revealed a high percentage of variability among individuals within populations (85.84%) than among the populations (14.16%). Similarly, a high variance was observed among the individuals within the country of origins (90.45%) than between the countries of origins. The grouping of genotypes in clusters was not related to their geographic origin indicating considerable gene flow among sesame genotypes across the selected geographic regions. The SSR markers used in the present study were able to distinguish closely linked sesame genotypes, thereby showing their usefulness in assessing the potentially important source of genetic variation. These markers can be used for future sesame varietal classification, conservation, and other breeding purposes.

• Mycobiology
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• 제49권4호
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• pp.376-384
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• 2021

Agaricus bisporus is a popular edible mushroom that is cultivated worldwide. Due to its secondary homothallic nature, cultivated A. bisporus strains have low genetic diversity, and breeding novel strains is challenging. The aim of this study was to investigate the genetic diversity and population structure of globally collected A. bisporus strains using simple sequence repeat (SSR) markers. Agaricus bisporus strains were divided based on genetic distance-based groups and model-based subpopulations. The major allele frequency (MAF), number of genotypes (NG), number of alleles (NA), observed heterozygosity (HO), expected heterozygosity (HE), and polymorphic information content (PIC) were calculated, and genetic distance, population structure, genetic differentiation, and Hardy-Weinberg equilibrium (HWE) were assessed. Strains were divided into two groups by distance-based analysis and into three subpopulations by model-based analysis. Strains in subpopulations POP A and POP B were included in Group I, and strains in subpopulation POP C were included in Group II. Genetic differentiation between strains was 99%. Marker AB-gSSR-1057 in Group II and subpopulation POP C was confirmed to be in HWE. These results will enhance A. bisporus breeding programs and support the protection of genetic resources.

• 생명과학회지
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• 제16권6호
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• pp.1001-1005
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• 2006

SSR markers를 이용하여 벼의 품종간 유전적 유연관계 분석과 품종식별 방법에 대한 연구를 수행하여 얻어진 결과를 요약하면 다음과 같다. SSR primer 50개와 벼 보급종 21품종을 PCR 반응시킨 결과 다형성을 뚜렷하게 나타내는 primer는 23개였으며, 각 marker에 의해 발생된 대립유전자의 수는 $2{\sim}9$까지 검출되었고, 평균값은 3.00개로 나타났다. 유전적 다형성 정도를 나타내어 주는 SSR marker의 PIC 값은 최소 0.091에서부터 최대 0.839까지 다양하게 분석되었다. SSR marker를 이용하여 분석된 벼 21품종에 대한 전체 유전적 유사도는 $0.59{\sim}0.92$의 범위에 속하였고 유사도 지수 0.65를 기준으로 할 때 4개의 그룹으로 구분되었다. SSR marker중에서 RM206, RM225, RM418, RM478은 marker genotype에 의해 21 품종에 대해 각각 고유한 밴드 특성을 나타내어 품종판별이 가능한 것으로 나타났다. 금후 이 연구결과는 벼 보급종의 품종식별을 위해 효과적으로 이용될 수 있는 것으로 나타났다.

• 한국과학교육학회지
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• 제41권5호
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• pp.415-428
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• 2021

COVID-19로 인하여 도입된 원격 과학 수업은 이제 교사들에게 새로운 일상으로 받아들여진다. 이러한 상황에서 교사가 지난해의 실행을 습관적으로 되풀이하기보다는 변화하는 맥락을 적극적으로 해석하고, 맥락에 적절한 학습 환경을 조성하는 것이 요구된다. 본 연구에서는 COVID-19로 인하여 시행된 원격 수업 2년 차 상황에서 교사가 문제를 인식하고, 이를 해결하는 실행에서 드러나는 교사 행위주체성과 이때의 맥락을 분석하였다. 특히, 2020년 4월에서부터 2021년 7월까지 16개월 동안 교사의 원격 과학 수업 실행을 추적하여 맥락에 따라 변화하는 교사의 행위주체성을 탐색하였다. 이를 위하여 중등학교 과학교사 3인을 대상으로 질적 사례 연구를 진행하였다. 연구 참여자와의 인터뷰, 연구 참여자가 사용한 교육자료를 수집하고, 이를 지속해서 검토하며 분석하였다. 연구 결과, 교사는 스스로 자신의 수업을 비판적으로 성찰함으로써 자신의 원격 과학 수업 실행에서의 문제를 인식하고 이를 해결하기 위한 행위주체성을 발현하거나 외부로부터의 변화에 능동적으로 적응하기 위하여 행위주체성을 발현하거나 자신이 추구하는 과학 교육을 원격 수업 상황에서도 구현하기 위하여 행위주체성을 발현하였다. 그리고 이 과정에서 지난해 원격 과학 수업을 실행한 경험 및 이로부터 축적된 실천적 지식, 자신의 실행에 대한 성찰, 원격 과학 수업에 대한 장·단기적 목표가 영향을 미쳤다. 또한, 교사가 속한 맥락에서 원격 수업의 질 제고를 추구하는 학교 공동체의 분위기나 교사 사이의 활발한 소통과 협력 역시 교사 행위주체성 발현을 촉진하였다. 본 연구는 우리나라 원격 과학 수업 상황에서 어떠한 과학교사 행위주체성이 발현되었는지 탐색하였으며, 이 과정에서 영향을 미친 맥락을 분석하였다. 또한, 같은 교사가 상황이 변화함에 따라 행위 주체성 발현에 어떠한 변화가 나타나는지, 그리고 그 과정에 영향을 미치는 맥락을 이해하기 위하여 교사의 개인적인 요인 및 맥락적 요인을 분석하였다. 이를 통하여 교사 행위주체성 발현을 지원할 수 있는 전략을 마련하는 데 시사점을 제시하고자 한다.

• International Journal of Industrial Entomology and Biomaterials
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• 제30권1호
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• pp.6-16
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• 2015

This study established the genetic characterisation of 10 microsporidian isolates infecting non-mulberry silkworms (Antheraea assamensis and Samia cynthia ricini) collected from biogeographical forest locations in the State of Assam, India, using PCR-based markers assays: inter simple sequence repeat (ISSR) and random amplified polymorphic DNA (RAPD). A Nosema type species (NIK-1s_mys) was used as control for comparison. The shape of mature microsporidian spores were observed oval to elongated, measuring 3.80 to $4.90{\mu}m$ in length and 2.60 to $3.05{\mu}m$ in width. Fourteen ISSR primers generated reproducible profiles and yielded 178 fragments, of which 175 were polymorphic (98%), while 16 RAPD primers generated reproducible profiles with 198 amplified fragments displaying 95% of polymorphism. Estimation of genetic distance coefficients based on dice coefficients method and clustering with un-weighted pair group method using arithmetic average (UPGMA) analysis was done to unravel the genetic diversity of microsporidians infecting Indian muga and eri silkworm. The similarity coefficients varied from 0.385 to 0.941 in ISSR and 0.083 to 0.938 in RAPD data. UPGMA analysis generated dendrograms with two microsporidian groups, which appear to be different from each other. Based on Euclidean distance matrix method, 2-dimensional distribution also revealed considerable variability among different identified microsporidians. Clustering of these microsporidian isolates was in accordance with their host and biogeographic origin. Both techniques represent a useful and efficient tool for taxonomical grouping as well as for phylogenetic classification of different microsporidians in general and genotyping of these pathogens in particular.

• 원예과학기술지
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• 제29권6호
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• pp.600-609
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• 2011

Allium속에 포함된 6종의 122점을 수집하고, 이 종들의 유전적 관계는 ISSR 마커를 이용하여 확인하였다. 형태적 분석은 6개의 양적 형질을 측정하고 1개의 질적 형질은 수치화하였다. SSR 분석은 17개의 primer를 사용하여 총 370개의 다형성 밴드를 얻었다. 형태적 특성 분석은 유전적 거리로 구분할 경우 3개의 그룹으로 분류되었으나, 부분적으로 몇 몇 종들은 분류에 어려움이 있었다. ISSR 결과를 바탕으로 Allium 속의 군집분석은 5개의 그룹으로 분리되었다. 형태적 분석과 SSR분석 간의 상관 관계는 유의성이 매우 낮았다(r = 0.036). 따라서 본 연구에서 개발한 ISSR 마커는 달래와 산달래의 분류와 교배 육종에 유용하게 이용될 수 있을 것이다.

• 폴리머
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• 제32권2호
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• pp.150-156
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• 2008

Two different polyacrylonitrile samples (PANs, triad tacticity fraction is 0.25 and 0.64) were synthesized and used to study the kinetics of cyclization. Polymers were treated at different temperatures between 250 to $300^{\circ}C$ under air atmosphere, and analyzed by X-ray diffractometer. The sharp and strong peak at $2{\theta}=16.5^{\circ}$ corresponds to a lateral repeat distance that is the (100) diffraction in hexagonal lattice, while the peak at $2{\theta}=25.5^{\circ}$ reflects the (101) diffraction. In comparing their areas of different heat treated samples, the cyclization of both PANs was identified as a first-order reaction. The rate constants of cyclization reaction at different temperatures and the active energy parameter were obtained. This results might provide an important effect on pre-oxidation of polyacrylonitrile fiber.

• Bulletin of the Korean Chemical Society
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• 제31권5호
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• pp.1165-1171
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• 2010

The lyotropic mesomorphism of lamellar liquid crystalline phase was examined by observing the swelling behavior of Distearoylphosphatidylcholine(DSPC) in glycerin and panthenol without water. The lyotropic mesomorphism was examined by using DSC, XRDs and Cryo-SEM. Increase of two polar solvents under non-hydrous condition showed distinctive differences in the lyotropic mesomorphism from forming different anisotropic structures with DSPC. Glycerin did not affect to the crystalline region of lamellar phase, whereas typical swelling mesomorphism was shown in the noncrystalline region. In contrast, panthenol showed some effect on the crystalline region, but common swelling mesomorphism was found in the non-crystalline region. In this case, the isopropyl and propyl groups in panthenol were the main factor to affect to the lipophilic domain in the crystalline region of lamellar phase. Also, it was found that the formation of well-arranged lamellar structure only by introducing glycerin and panthenol as a solvent without water, was possible. These results were confirmed by examination of the swelling mesomorphism of liquid crystal membrane triggered by introducing the two polar solvents.

• Journal of Forest and Environmental Science
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• 제24권1호
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• pp.27-34
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• 2008

Level and distribution of genetic diversity in seven populations of Albizia lucida Benth. in eastern region of the Indian sub-continent were estimated using ISSR markers. Relatively higher level of genetic diversity within populations was observed in seven populations of A. lucida (mean of 0.38). From the result of AMOVA, majority of genetic diversity was allocated within populations (96.2%) resulting in a moderate degree of population differentiation. The observed distribution pattern of I-SSR variant among the populations was coincided with the typical pattern of long-lived woody tree species. Genetic relationships among the populations, reconstructed by UPGMA method, revealed two genetic groups. The population of Anugul and Bargarh turned out to be the most closely related despite a distance location between them. These formations will be of great value in the development of conservation plans for species exhibiting high levels of genetic differentiation due to fragmentation, such as indication of conservation unit size, which populations should be chosen as priority in conservation plans and which samples should be introduced in areas with a low number of individuals of A. lucida.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제13권11호
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• pp.5335-5353
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• 2019

The definition of the bandwidth efficiency (BE) of cognitive cooperative network (CCN) is the ratio between a number of the licensed slot(s) or sub-channel(s) used by the unlicensed users to transmit a single data packet from the unlicensed transmitter to unlicensed destination, and from unlicensed relay(s) to unlicensed destination. This paper analyzes and improves the BE in the underlay CCN with a new reactive relay selection under interference and power constraints. In other words, this paper studies how unlicensed cooperative users use the licensed network slot(s) or sub-channel(s) efficiently. To this end, a reactive relay selection method named as Relay Automatic Repeat Request (RARQ) is proposed and utilized with a CCN under interference and power constraints. It is shown that the BE of CCN is higher than that of cooperative transmission (CT) due to the interference and power constraint. Furthermore, the BE of CCN is affected by the distance of the interference links which are between the unlicensed transmitter to the licensed destination and unlicensed relay to the licensed destination. In addition, the BE for multiple relays selection over a CCN under interference and power constraints is also analyzed and studied, and it is shown that the BE of CCN decreases as the number of relays increases.