• Korean Journal of Plant Taxonomy
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• v.48 no.1
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• pp.1-8
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• 2018

Mankyua chejuense is the only member of the monotypic genus Mankyua (Ophioglossaceae) and is endemic to Jejudo Island, Korea. To determine the precise phylogenetic position of M. chejuense, two cpDNA regions of 42 accessions representing major members of lycophytes are obtained from GenBank and analyzed using three phylogenetic analyses (maximum parsimony, maximum likelihood, and Bayesian inference). In addition, the divergence time is estimated based on a relaxed molecular clock using four fossil calibration points. The phylogenetic position of Mankyua still appears to be uncertain, representing either the earliest diverged lineage within Ophioglossaceae or a sister to the clade containing Ophioglossum and Helminthostachys. The most recent common ancestor of Ophioglossaceae and its sister lineage, Psilotum, was estimated to be 256 Ma, while the earliest divergence of Mankyua was estimated to be 195 Ma in the early Jurassic.

• Journal of Food Hygiene and Safety
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• v.11 no.2
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• pp.115-121
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• 1996

In order to compare the suppressive effect of quercetin and several its glycosides, such as quercitrin (quercetin-3-rhamnoside), isoquercitrin (quercetin-3-glucoside), hyperin (quercetin-3-galactoside) and tutin (quercetin-3-rhamnosyl glucoside), on the genotoxicity by N-methyl-N-nitrosourea(MNU), in vitro sister chromatid exchange(SCE) test using mouse spleen lymphocytes and in vivo micronucleus test using mouse peripheral blood were performed. MNU-induced SCEs in vitro were not decreased by the simultaneous treatment of test compounds. Among them, quercetin and hyperin showed significant suppressive effects at high dose(10-5M). On the other hand, MNU-induced micronucleated reticulocytes(MNRETS) in vivo were significantly decreased with good dose-dependent manner in all compound tested. However, there were not significant differences between quercetin aglycone and its glycosides in the suppressive aglycone and its glycosides may act as an antigenotoxic agent in vivo and may be useful as a chemopreventive agent of alkylating agent.

• Nutritional Sciences
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• v.5 no.3
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• pp.134-145
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• 2002

No Abstract, See Full-text

• Toxicological Research
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• v.11 no.1
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• pp.117-125
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• 1995

In order to examine the mechanism of asbestos clastogenicity, CHO cells were treated with chrysotile and crocidolite. Crocidolite and chrysotile were able to induce lipid peroxidation in a dose dependent manner. Ultrafiltrate of culture media from CHO cells treated with chrysotile/crocidolite induced sister chromatid exchange in CHO cells. Ultrafiltrate of culture media from CHO cells treated with chrysotile induced chromosome aberration but it was not statistically significant. Simultaneous treatment of 3-Aminobenzamide (3-AB) or cytosine arabinoside (Ara C) with crocidolite had no effect on the frequency of chromosome aberration by crocidolite whetease posttreatment of caffeine significantly increased the chromosomel aberration by crocidolite. This indicated that DNA damage by asbestos took place at late stage of cell cycle. The results suggested that the ultrafiltrate of media contained clastogenic factor (CF) and lipid peroxidation might be involved in the formation of CF.

• Environmental Mutagens and Carcinogens
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• v.16 no.2
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• pp.117-123
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• 1996

This study was carried out to examine the mechanism of Arsenic cytotoxicity through several in vitro test systems. Dose-dependent decrease of cell survival by Arsenic was observed by colony forming assay. Arsenic was weak mutagenic in inducing HGPRT point mutation in CHO cells. The frequency of chromosomal aberrations increased in a dose-dependent manner and the most frequent type of chromosomal aberrations induced by Arsenic were chromatid type deletions. U!trafiltrates of culture media from CHO cells treated with Arsenic induced sister chromatid exchanges(SCE) in CHO cells and Arsenic was able to induce lipid peroxidation in CHO cells. The results suggested that the ultrafiltrates of media from CHO cells treated with Arsenic contain clastogenic factor(CF) and Iipid peroxidation might be involved in the formation of CF.

• Language and Information
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• v.3 no.2
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• pp.85-96
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• 1999

This paper deals with questions involving the polysemous meanings of Korean delimiter to, which include existence of a sister item, polar values, emphasis, reciprocality, and concession among others. In this paper it is argued that the basic meaning of to is the implication of a sister proposition and that various other meanings can be pragmatically derived from the basic meaning. The pragmatic notion of emphasis is defined formally and it is shown that various meanings of to can be accounted for by investigating how the speaker exploits the background knowledge which the speaker and the listener share in a speech context. According to what type of the context is made use of by the speaker, the various polysemous meanings are analyzed as involving either a simple implicature or a series of implicatures, i.e., scalar implicatures, so the various meanings of the delimiter can be attributable to the different attunement of the speaker to different kinds of context.

• Toxicological Research
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• v.9 no.1
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• pp.45-60
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• 1993

The present study was carried out to evaluate the cytotoxicity of cadmium on cultured rat fibroblasts. The colorimetric assays of neutral red and tetrazolium MTT, the lactatedehydrogenase activity, the amounts of total protein, the rate of DNA synthesis, the amounts of unscheduled DNA synthesis, the frequency of sister chromatid exchange, the releasing rate of intracellular calcium, and light and electron microscopic studies were performed on cultured rat fibroblasts maintained in the media containing various concentrations of cadmium. The results were as follows: The neutral red(NR) and MTT values were decreased dose-dependently by cadmium, and the NR90, NR50, MTT90 and MTT50 values of cadmium were 0.2mM, 21.5mM, 1.0Mm and 60.0Mm, respectively.

• English & American cultural studies
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• v.18 no.3
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• pp.31-63
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• 2018

The purpose of this paper is to investigate the attitudes and practices of life demanded for authentic existence in adversity, focusing on Toni Morrison's Home which was published in 2012. Home portrays the journey of Frank Money, an African-American veteran of the Korean War who strives to extricate his sister Cee from inhumane violence. Through this work, Morrison criticizes prevalent racism in the 1950s which is regarded as a time of affluence and peace through this sibling's agony. In this paper, firstly I attempt to examine the aspects of racism which Frank and Cee face and their distorted survival strategies. Secondly I try to find the right direction of brother and sister relationship based on Frank and Cee who are compared to Hansel and Gretel. Thirdly I try to point out the importance of self-reflection required for the healing process of Frank and Cee who overcome adversity and restore their identity with the help of Samaritans. And I investigate the possibility of ethical practice going beyond my family to strangers.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.22
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• pp.9725-9730
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• 2014

Background: Sister chromatid exchange (SCE) in human peripheral blood lymphocytes is one of the most extensively studied biomarkers employed to evaluate genetic damage subsequent to pesticide exposure. Objective: To estimate the pooled levels of SCE in human peripheral blood lymphocytes among population exposed to pesticide. Materials and Methods: Meta-analysis on the association between SCE frequency and pesticide exposure was performed with STATA 10.0 software package and Review Manager 5.0.24 in this study. Results: The overall means of SCE were 7.88 [95% confidence intervals (95%CI): 6.71-9.04] for exposure group and 6.05 (95%CI: 5.13-6.95) for controls, respectively. There was statistically significant difference in the SCE frequency in human peripheral blood lymphocytes between pesticide-exposed groups and control groups, and the summary estimate of weighted mean difference was 1.69 (95%CI: 1.01-2.38). We also observed that pesticide-exposed population had significantly higher SCE frequency than control groups among smokers, nonsmokers, pesticide applicator, pesticide producer, other exposure population and Asian population in stratified analyses. Conclusions: Data indicate that the SCE frequency in human peripheral blood lymphocytes might be an indicator of early genetic esffects for pesticide-exposed populations.

• Journal of Korean Biological Nursing Science
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• v.2 no.2
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• pp.90-101
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• 2000

This study is being carried out, in two different random sample groups, between 20 men who were radiation exposed workers in the two general hospitals located in "T" city as a experimental group and 20 healthy men who were non-radiation exposed workers as a control group. The occurring frequency of the sister chromatid exchange as a biological dosemeter of radiation were studied. And the age, duration of employment and smoking were used as variable for the experiment. The results are as follows : The frequency of SCE were noticed respectively by each variable : 1) by age as a variable, the frequency were increased notably in radiation exposed workers group rather than a control group(p<0.05). 2) by duration of employment, the difference of the frequency were not recognised significantly in statistical among radiation exposed workers. 3) in smoker the frequency were increased notably in a radiation exposed workers than a control groups(p<0.05). Taking into consideration the above results, the age and smoking could affect the frequency of SCE, however, the size of sample were too small to generalize. Therefore, the following suggestions are recommended to get more accurate result. 1) In order to clarify the correlation in a smoking as variable, finding the volume of smoking and its related factor are necessarily required. 2) In order to confirm the correlation in each variable, adopting of a bigger-sized sample are needed and the study itself also be carried out repeatedly.