• Journal of Plant Biotechnology
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• v.6 no.1
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• pp.25-37
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• 2004

Successful genetic transformation of plants requires non-chimeric selection of transformed tissues and their subsequent regeneration. With rare exceptions, most transformation protocols still rely heavily on antibiotics for selecting transgenic cells that contain an antibiotic-degrading selectable marker gene. Here, the morphogenic capacity of in-vitro explants of chrysanthemnum and tobacco stems and leaves (control and transgenic) changed with the addition of aminoglycoside antibiotics (AAs), In a test of 6 AAs, phytotoxicity occurred at concentrations of 10 to 25 and 50 to 100$\mu\textrm{g}$ $mL^{-1}$ in chrysanthemum and tobacco explants, respectively. Light conditions as well as explant source and size also had significant effects. The use of transverse thin cell layers (tTCLs), in conjunction with high initial AA selection levels, supported the greatest regeneration of transgenic material (adventitious shoots or callus) and the lowest number of escapes. Flow-cytometric analyses revealed no endodu-plication in chrysanthemum, even at high AA levels. However, this phenomenon was observed in tobacco calli(8C or more), even at low AA concentrations (i.e., 5 to 10 $\mu\textrm{g}$ mL$^{-1}$ ).

• Journal of Environmental Science International
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• v.15 no.12
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• pp.1103-1107
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• 2006

Iris odesanensis Y.N. Lee is one kind of species among 54 endangered plant species designated by the Ministry of Environment in Korea. It is very rare native plant throughout the country. Therefore, this study was conducted to investigate the native Iris odesanensis in Mt. Naeyon for their distribution and ecological characteristics. They were mostly distributed mid-slope of the mountain from 443m to 498m altitude. They were located lower part of valley and provided enough humid condition. They had proper light and humidity conditions as they faced south south west, south south east, and south. They were also located at the places deciduous woody plants were distributed for proper light conditions for spring blooming. Iris flowered to use light at the period before the trees thickly covered with foliage. However this unfavorable light condition caused low percentage as 7.04% of blooming individuals in this study. In herbaceous, Vioia chaerophylloides(Regel) W. Hocker, Carex siderosticta Hance, Erythronium japonicum Decne., Oxalis obtriangulata Max., Hepatica asiatica Nakai, Lilium tsingtauense Gilg et cetera were appeared well. We propose that proper pruning of upper branches of the deciduous trees is needed for suitable light condition of management of native sites.

• Nuclear Engineering and Technology
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• v.49 no.2
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• pp.327-334
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• 2017

Common-cause failure (CCF) events can significantly impact the availability of safety systems of nuclear power plants. For this reason, the International Common Cause Data Exchange (ICDE) project was initiated by several countries in 1994. Since 1997 it has been operated within the Organisation for Economic Co-operation and Development (OECD)/Nuclear Energy Agency (NEA) framework and has successfully been operated over six consecutive terms (the current term being 2015-2017). The ICDE project allows multiple countries to collaborate and exchange CCF data to enhance the quality of risk analyses, which include CCF modeling. As CCF events are typically rare, most countries do not experience enough CCF events to perform meaningful analyses. Data combined from several countries, however, have yielded sufficient data for more rigorous analyses. The ICDE project has meanwhile published 11 reports on the collection and analysis of CCF events of specific component types (centrifugal pumps, emergency diesel generators, motor operated valves, safety and relief valves, check valves, circuit breakers, level measurement, control rod drive assemblies, and heat exchangers) and two topical reports. This paper presents recent activities and lessons learnt from the data collection and the results of topical analysis on emergency diesel generator CCF impacting entire exposed population.

• Journal of Plant Biotechnology
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• v.40 no.1
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• pp.43-48
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• 2013

Oreorchis coreana Finet is threatened globally by over-collection from its natural habitats for horticultural purposes. Its rarity in nature makes this plant one of the most endangered species in Korea. In this study, we investigated the effects of sodium hypochlorite (NaOCl) on orchid seed viability and seed germination. An in vitro bioassay swelling test using immature seeds was compared with a standard chemical procedure using triphenyl tetrazolium chloride (TTC) to test seed viability. In general, the bioassay was more appropriate for estimating embryo viability after a prolonged pre-treatment (more than 1 h) in 1% NaOCl, a surface sterilant often used to enhance germination of seeds of terrestrial plants. Therefore, an efficient method for investigating in vitro swelling of immature seeds is urgently needed. We established a method for determining the viability and swelling of O. coreana seeds via in vitro examination of immature seeds. Treatment of immature seeds with 1% NaOCl for 10 min greatly enhanced the extent of swelling of immature zygote embryos when compared to untreated seeds. These data obtained here appear to be comparable to viability and swelling that occurs in O. coreana seeds via asymbiotic germination.

• Journal of Species Research
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• v.7 no.4
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• pp.354-362
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• 2018

Population genetic assessment is essential for the conservation and management of endangered and rare plants. Neofinetia falcata is endangered epiphyte orchid and protected by law in Korea. In Korea, this species is only found on islands in the South Sea of Korea (including Jeju-do) and the southern coast of the Korean Peninsula. We developed nine microsatellite makers to assess the genetic diversity and population genetic structure of three populations of N. falcata. The genetic diversity at the species level was low, which can be attributed to inbreeding or fragmentation into small, isolated populations. A recent bottleneck was detected in one population, likely due to overcollection. N. falcata exhibited moderated levels of differentiation among populations, with the three populations were divided into two clusters based on genetic structure. The genetic diversity and structure of N. falcata are affected by restricted gene flow by pollen or seeds due to isolation and geographic distance. Strategies for in situ and ex situ conservation of this species are been proposed based on the results of our study.

• Journal of Plant Biotechnology
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• v.47 no.1
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• pp.73-77
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• 2020

This study was conducted to examine the vitality of Bletilla striata Rchb.f. seed treated with different concentrations sodium hypochlorite (NaOCl) for different lengths of time. This study also examined the effect of NaOCl treatment times and concentrations on swelling formation and seed germination of B. striata seed. The non-treated B. striata seed had the highest survival rate (82.7%) Treatment with more than 1.5% NaOCl negatively affected the seed survival rate, as compared to concentrations of less than 1%. The swelling formation and seed germination percentages were highest (90.1% and 94.1%, respectively) when seeds were treated with 0.5% NaOCl for 20 min. These results can be used as important basic data for the growth and restoration of B. striata and further suggest the possibility of individual restoration in habitats.

• Korean Journal of Heritage: History & Science
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• v.36
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• pp.313-334
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• 2003

Historically, hawking/falconry refer to the hunting for pheasants, birds and hares using a hawk. In spite of its long history, not so many studies were found and/or have been performed. Examining researches, hawking has been enjoyed solely by the royal families until the early Joseon Dynasty but it has been popularly spread among the people in the 18th century, emphasizing recreational factors of it. The researches, however, dealt only with the limited data published by the government while a diary, Swaemirok written by Oh Hi-Mun, an intellectual in the 16th century noted the realities and characteristics of hawking at that time. According to the diary, hawking has been spread all over the country in the 16th century and the people as well as the royal families enjoyed it. The hawking season has been continued for a year except for summertime trees and plants grow thick. For the hawking, they need to be permitted officially or under a tacit consent. In those days, beef and pork are very rare. A peasant acted as, therefore, an excellent alternative and was served up for a religious service. In view of the truth, it could be stated that peasant-hawking was important for recreational activities as well as for their living.

• Nuclear Engineering and Technology
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• v.54 no.6
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• pp.2084-2093
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• 2022

Probabilistic safety assessment is widely used to quantify the risks of nuclear power plants and their uncertainties. When the lognormal distribution describes the uncertainties of basic events, the uncertainty of the top event in a fault tree is approximated with the sum of lognormal random variables after minimal cutsets are obtained, and rare-event approximation is applied. As handling complicated analytic expressions for the sum of lognormal random variables is challenging, several approximation methods, especially Monte Carlo simulation, are widely used in practice for uncertainty analysis. In this study, a theoretical approach for analyzing the sum of lognormal random variables using an efficient numerical integration method is proposed for uncertainty analysis in probability safety assessments. The change of variables from correlated random variables with a complicated region of integration to independent random variables with a unit hypercube region of integration is applied to obtain an efficient numerical integration. The theoretical advantages of the proposed method over other approximation methods are shown through a benchmark problem. The proposed method provides an accurate and efficient approach to calculate the uncertainty of the top event in probabilistic safety assessment when the uncertainties of basic events are described with lognormal random variables.

• Korean Journal of Soil Science and Fertilizer
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• v.37 no.5
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• pp.341-349
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• 2004

This study was conducted to compare the effects of arbuscular mycorrhizal fungi (AMF) on the growth and fruit yield of hydroponically grown cucumber and tomato plants in solid medium culture. Mycorrhizal fungus Glomus sp. was collected from plastic film house soils of cucumber and tomato and inoculated to the experimental crops at the time of seeding and transplanting. Root infection of cucumber and tomato plants by AMF was more significantly increased when the AMF was inoculated at seeding stage than at transplanting stage. In the infected roots of cucumber and tomato, mycorrhizal hyphae was easily observed but vesicle and arbuscule were rare. Overall plant growth was increased with AMF inoculation and the growth was higher when AMF was inoculated at seeding stage. Fresh weight of each fruit of cucumber and tomato and sugar content in tomato fruits were significantly increased with AMF inoculation at seeding stage. The AMF inoculation also increased fruit yields of cucumber and tomato.

• Korean Journal of Environmental Biology
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• v.37 no.4
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• pp.690-706
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• 2019

Paddy fields play an important role in the biodiversity conservation of agroecosystems as man-made wetlands. This study focused on the floristic composition and characteristics of paddy fields in South Korea. The flora surveys were conducted in 33 areas in nine provinces at two times (June and August) in 2016. The results showed that the vascular plants of the paddy fields in South Korea included 389 taxa, composed of 51 families, 219 genera, 350 species, four subspecies, 30 varieties, and five forms. Among the 51 families, Gramineae was the most diverse in species (76 taxa), followed by Compositae (61 taxa), Leguminosae (32 taxa), Cyperaceae (27 taxa), Polygonaceae (15 taxa), and Scrophulariaceae (12 taxa). Based on the occurrence frequency of each species, Digitaria ciliaris (Retz.) Koel. (100%), and Echinochloa crus-galli (L.) P.Beauv. (100%) were the highest, followed by Acalypha australis L. (97.0%), Bidens frondosa L. (97.0%), Alopecurus aequalis Sobol. (97.0%), Rorippa palustris (Leyss.) Besser (93.9%), Ludwigia prostrata Roxb. (93.9%), Lemna perpusilla Torr. (93.9%), Mazus pumilus (Burm. f.) Steenis(90.9%), Rorippa palustris(Leyss.) Besser(87.9%), Eclipta prostrata(L.) L.(87.9%), Commelina communis L.(87.9%), Artemisia princeps Pamp.(84.8%), Erigeron annuus (L.) Pers.(84.8%), Cyperus microiria Steud.(84.8%), and Aneilema keisak(Hassk.) Hand.-Mazz. (81.8%). The biological type of paddy fields in South Korea was determined to be Th-R₅-D₄-t type. Rare plants were found in six taxa: Aristolochina contorta Bunge, Penthorum chinense Pursh, Sagittaria sagittifolia subsp. leucopetala (Miq.) Hartog, Ottelia alismoides (L.) Pers., Pseudoraphis ukishiba Ohwi, and Acorus calamus L. Eighty taxa contained naturalized plants composed of 15 families, 54 genera, 76 species, three varieties, and one form. The urbanization and naturalization indices were 24.8% and 20.6%, respectively.