• YAKHAK HOEJI
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• v.2 no.1_2
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• pp.1-8
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• 1953

The leaves of prunus padus L. var. Seoulensis Nakai distributed widely in Korea, were extracted with boiling alcohol(95%) after being mixed with calcium carbonate. The aqueous solution distilled off alcohol from the above filtered extract under the reduced pressure was evaporated to the dryness. The residue was extracted with acetic ether on the water-bath and the acetic ether solution extract was allowed to stand for a weck after removing out of acetic ether almostly, then a colorless necdles were Crystalized out which has the following characteristics : $C_{14}$ $H_{17}$ $O_{6}$ N, began to melt at 138-139.deg. bitter taste [.alpha.]$_$ $D^{20}$ ]=-26.99.deg. soluble in water, alcohol acetone acetic ether etc. slightly soluble in chloroform. It was proved to be identical with prunasine due to above characteristics and determination of Benzal-dehyde HCN and glucose respectively which was obtained on hydrolysis of this glycoside with emulsine.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2000.11a
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• pp.452-455
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• 2000

Superconducting power cable is one of the most promising energy application of high-T$_{c}$ superconductors (HTS). A prototype HTS cable have been constructed multi-layer cable using Bi-2223 tape and tested. The AC transport losses under self field were investigated at 77K on the 19 filamentary tape and multi-layer HTS cables. And we carried out numerical analysis using bean model. The result shows that the total transport current of HTS cable in L$N_2$ was 475[A], and transport current passed through almost the outer layer (2-layer). Also, AC transport losses in outer layer of HTS cable was proportion to I$^2$ and higher than losses of inner layer. In case of Ip=Ic, calculated numerical loss density was concentrated on the edge of tape and most of loss density in cable was distributed outer layer more than inner layer. As magnetic distribution was concentrated on outer layer.r.

• Proceedings of the PSK Conference
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• 2002.10a
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• pp.298.2-298.2
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• 2002

Bioflavonoids are semi-essential food components that are ubiquitously present in nature. It has been reported that flavonoids act as anti-oxidant as well as anti-cancer agents. Quercetin is one of the most widely distributed bioflavonoids in the plant kingdom. The goal of this study was to investigate effects of quercetin analogs extracted from Lindera erythrocarpa, quercetin 3-O-${\alpha}$-arabinofuranoside and quercetin 3-O-${\alpha}$-L -rhamnoside, on oxidatie stress-induced cell death. (omitted)

• Korean Journal of Plant Taxonomy
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• v.36 no.1
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• pp.61-89
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• 2006

Algific talus slopes are local cold micro-environmental habitats where cool air escapes through vents and fissures of talus layer, and ice forms in summer. To access the phytogeographical significance and to develop the conservation strategy on vegetation of the algific talus, plant species composition on seven algific talus in South Korea was investigated. As a results, phytogeographically significant northern elements such as Cystopteris fragilis (L.) Bernh., Diplazium sibiricum (Turcz. ex Kunze) Sa.Kurata, Polypodium virginianum L., Vaccinium vitis-idaea L. and Hackelia deflexa (Wahlenb.) Opiz were distributed in these algific talus slopes (below $N37^{\circ}43^{\prime}$). In addition, subalpine species such as Woodsia subcordata Turcz, Rosa suavis willd., Clematis fusca var. coreana ($H.L{\acute{e}}v.$ & Vaniot) Nakai, Calamagrostis langsdorfii (Link) Trin. and Carex vaginata var. petersii (C.A.Mey.) Akiyama were also distributed as typical relictual species of these algific talus (less than alt. 400m). The algific talus slopes in Korean peninsular can be regarded as the insular refugia that northern plant species advanced southward during the latest glacial age have been isolated and adapted in some local microhabitats. Because the algific talus slopes as paleorefugia are very important in terms of phytogeography as well as meteorology ans geology, developments of strategies for in situ and ex situ conservation on these small isolated and threatened populations associated with the algific talus urgently needed.

• Korean Journal of Ichthyology
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• v.32 no.2
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• pp.84-90
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• 2020

We investigated carbon and nitrogen isotope ratios (δ¹³C and δ¹⁵N) of the slipmouth Leiognathus nuchalis to reveal the effects of body size, feeding strategy and spatial distribution on the food resource utilization during the migration in the Seomjin estuary and Gwangyang Bay. The δ¹³C values of L. nuchalis caught in the Seomjin estuary where the salinity is lower than 30 psu were much lower than those in the deep-bay area of Gwangyang Bay. Such a spatial heterogeneity in δ¹³C values of the L. nuchalis clearly indicates active feeding within the estuarine habitat. In contrast, the δ¹⁵N values of L. nuchalis showed a consistency among sites, indicating that this species occupies identical trophic level across the whole area. The slipmouth distributed throughout the bay area, reflecting its euryhaline characteristics. However, the distribution pattern appeared to be separated according to body size into smaller individuals in the low-saline estuary and larger ones in the deep bay. Overall results support the plastic feeding strategy of the slipmouth from zooplanktonic (estuarine habitat) to epibenthic (deep-bay habitat) feeder during the migration between estuarine to deep-bay habitats.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.37 no.1
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• pp.1-8
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• 2001

This study deals with the experimental and numerical investigations to design the high performance otter board. Experiment was carried out to determine the most effective slot size of single-slot cambered otter board in the circulation water channel of BAEK KYUNG IND. Co. LTD. Numerical analysis was done by the commercial CFD code, FLUENT, to provide some valuable physical interpretations and finally to design the otter board section by numerical method. The major results are as follows ; 1. In experiment, the maximum lift and drag coefficients of simple cambered type otterboard were 1.41, 0.55, respectively, at the angle of attack $28^\circ$, while those of slot one with slot size 0.02C (C denotes the chord length) were 1.72, 0.42 at the angle of attack $24^\circ$. 2. The hydrodynamic characteristics depending upon slot size shows the greatest at 0.02C of the slot size. 3. Numerical results well visualized the streamlines, pressure fields, and speed vectors of a simple cambered and slot cambered otter board with slot size 0.02C. The slot cambered one with slot size 0.02C was shown that pressure field was distributed moderately on front and back side of otter board. And, the delay and decrease of separation were favorably achieved by flow through slot. 4. Computed result on the pattern of hydrodynamic field and the values of $C_L$ and $C_D$ by the commercial CFD code, FLUENT, show almost the same as those of the experimental result.

• Archives of Pharmacal Research
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• v.29 no.2
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• pp.123-130
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• 2006

1,4-Naphthoquinones are widely distributed in nature and many clinically important antitumor drugs containing a quinone moiety, such as anthracyclines, mitoxantrones and saintopin, show excellent anticancer activity. In this study, 2- or 6-substituted 5,8-dimethoxy-1,4-naphthoquinone (DMNQ) and 5,8-dihydroxy-1,4-naphthoquinone (DHNQ) derivatives were synthesized, and their cytotoxic activity against L1210 and P388 cancer cells was examined. Their antitumor activity was also assessed in mice bearing S-180 cells in the peritoneal cavity. In comparison with the DMNQ derivatives, the DHNQ derivatives exhibited more potent bioactivities than the DMNQ derivatives against both L1210 and P388 cells in vitro and S-180 cells in vivo. The $ED_{50}$ values of the DHNQ derivatives against P388 cells were in the range of 0.18-1.81 ${\mu}g/mL$ whereas those of the DMNQ derivatives were in the range of 0.26-40.41 ${\mu}g/mL$. The T/C ($\%$) values of the DHNQ derivatives, 8, 17, 18, 19, and 20, were found to be comparable to or even better than that of adriamycin. It was also observed that the 2-substituted derivatives (8, 19, 20) showed better antitumor activity than the 6-substituted derivatives (7, 17, 18) in the mice bearing S-180 cells in the peritoneal cavity.

• Proceedings of the Ginseng society Conference
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• 1988.08a
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• pp.141-146
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• 1988

Dwarf ginseng (Panax trifolius L.) is a member of the ginseng family (Araliaceae). which is indigenous to North America and is distributed from Southern Canada to the Northern United States. In total. nine compounds were isolated from the leaves of Dwarf gineng. Of these. four were identified as flavonoids and five were found to be ginsenosides. Two of the flavonoids were identified to be kaempferol-3. 7-dirhamnoside and kaempferol-3-gluco-7-rhamnoside. Four of the ginsenosides were identified as notoginsenoside-Fe. ginsenoside-Rd. ginsenoside-Rc and $ginsenoside-Rb_1$ The common aglycone of these ginsenosides was shown to be (20S)-protopanaxadiol. The identification of flavonoids and ginsenosides from the root. stem. leaf. flower and fruit of Dwarf ginseng was detected by Two-Dimensional Thin-Layer Chromatography (2D-TLC) and High Performance Liquid Chromatography (HPLC). The quantitation of flavonoids and ginsenosides from the root. stem. leaf. flower and fruit of Dwarf ginseng and related species such as Korean gineng (Panax ginseng C.A. Meyer) and American ginseng (Panax quinquefolium L.) was analyzed by HPLC only. Three flavonoids (Kaempferol derivatives) labelled compound 1 $(10.8\%)$, compound 3 ($2.8\%$), and compound 4 ($8.4\%)$ were found in the root of Dwarf ginseng but not found in the roots of Korean ginseng and American ginseng. This is the first time that flavonoids have been found and identified in roots of the ginseng family (Araliaceae).

• The Korean Journal of Ecology
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• v.16 no.4
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• pp.501-514
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• 1993

In order to study the ecotypic variation of Robinia pseudo-acacza L. distributed in southern area of Korean peninsula, 15 local populations(Daejin, Sokcho, Kangneung, Mt. Surak, Hongcheon, Kwangneung, Namhansanseong, Chungju, Yesan, Andong, Jeonju, Dalseong, Changweon, Mokpo and Wando), located from $34^{\circ}18'N\;to\;38^{\circ}36'N$, were selected based on their latitudes and geographical distances. Seeds of these populations were collected and their germination and growth of seedlings were investigated. The optimum temperature of seed germination tends to decrease with ascending latitudes. The optimum temperatures of local populations were classified into three types: the north central type of $25^{\circ}C$(Daejin, Sokcho, Kangneung, Mt. Surak, Hongcheon, Kwangneung), the south central type of $30^{\circ}C$(Narnhansanseong. Chungju, Yesan, Andong, Jeonju), and the southern type of $35^{\circ}C$(Dalseong, Changweon, Mokpo, Wando). The optimum temperature for the growth of seedlings was $25^{\circ}C$ for all populations. The populations were also classified into three types : north central type, south central type and southern type based on the ranking on the growth of seedlings at 5 different temperatures of 15, 20, 25, 30 and $35^{\circ}C$, and the results of seedling growth showed similar patterns to those of the seed germination.

• Korean Journal of Plant Taxonomy
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• v.47 no.2
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• pp.161-169
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• 2017

The genome size is one of the basic characters of an organism, and it is widely applied in various fields of biology, such as systematics, breeding biology, population biology, and evolutionary biology. This factor was recently highlighted in genome studies because choosing a representative of a plant group having the smallest genome size is important for the efficiency of a genome project. For the estimation of the genome size, flow cytometry has recently been highlighted because it is a convenient, fast, and reliable method. In this study, we report the genome sizes of 15 taxa of Lamiaceae from nine genera distributed in Korea using flow cytometry. Data pertaining to the genome size for all of our species have not been reported thus far, and the data from Agastache, Clinopodium, Elsholtzia, and Isodon are the first reported for each genus. The genome sizes of 15 genera and 39 species were reported to the Plant DNA C-values Database (http://data.kew.org/cvalues/). Scutellaria indica L. has a genome size of 0.37 pg (1C). This is the fourth smallest value among the 98 Lamiaceae taxa in the Angiosperm DNA C-value Database, indicating that this taxon can be used as a reference species in the genome studies in Lamiaceae as a native Korean species. The largest genome size observed in this study is in Phlomis umbrosa Turcz. (1C=2.60 pg), representing the possible polyploidy origin of this species in the family.