• Journal of Korean society of Dental Hygiene
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• v.16 no.6
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• pp.1047-1055
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• 2016

Objectives: The purpose of the study was to investigate the factors influencing turnover intention in new dental hygienists. Methods: A self-reported questionnaire was filled out by 202 new dental hygienists in Gyeonggido, Chungcheongdo, Jeollado, and Gyeongsangdo from March 1 to April 24, 2016. Data were analyzed using SPSS WIN 19.0 program. The questionnaire consisted of general characteristics of the subjects (7 items), job-related characteristics (6 items), turnover intention (7 items), burnout (6 items), job satisfaction (13 items), job stress (10 items), organizational commitment (6 items), and critical thinking disposition (8 itmes). Results: Turnover intention was 2.92 points and burnout was 3.26 points. Each of job satisfaction, organizational commitment, and critical thinking disposition was 3.27, 2.95, and 3.32, respectively. Conclusions: The factors influencing turnover intention included age, job stress, job satisfaction, job burnout, and organizational commitment. Among them, job burnout had the highest impact on turnover intention.

• Korean Journal of Pharmacognosy
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• v.43 no.4
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• pp.345-351
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• 2012

In this study, 49 Korean herbal medicines have been investigated with an in vitro evaluation system using glycation end products (AGEs) formation inhibitory activity. Of these, 18 herbal medicines ($IC_{50}$ < $50{\mu}g/ml$) were found to have significant AGEs formation inhibitory activity. Of these, five herbal medicines ($IC_{50}$ < $50{\mu}g/ml$) were found to have significant AGEs formation inhibitory activity. Particularly, Mallotus japonicus (twigs and leaves), Rhus javanica (twigs and leaves), Boehmeria nivea (whole plants), Quercus acuta (stems), and Eurya japonica (stems) showed more potent inhibitory activity (approximately 9-37 fold) than the positive control aminoguanidine ($IC_{50}=76.47{\mu}g/ml$).

• The Mathematical Education
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• v.48 no.2
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• pp.149-167
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• 2009

This study was aimed to examine problem-solving ability of fifth graders on two types of mathematical essay problems, and to analyze the process of mathematical justification in solving the essay problems. For this purpose, a total of 14 mathematical essay problems were developed, in which half of the items were single tasks and the other half were data-provided tasks. Sixteen students with higher academic achievements in mathematics and the Korean language were chosen, and were given to solve the mathematical essay problems individually. They then were asked to justify their solution methods in groups of 4 and to reach a consensus through negotiation among group members. Students were good at understanding the given single tasks but they often revealed lack of logical thinking and representation. They also tended to use everyday language rather than mathematical language in explaining their solution processes. Some students experienced difficulty in understanding the meaning of data in the essay problems. With regard to mathematical justification, students employed more internal justification by experience or mathematical logic than external justification by authority. Given this, this paper includes implications for teachers on how they need to teach mathematics in order to foster students' logical thinking and communication.

• Korean Journal of Pharmacognosy
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• v.42 no.2
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• pp.187-194
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• 2011

Aldose reductase (AR), the key enzyme in the polyol pathway, plays an important role in the development of the diabetic complications. None of Aldose reductase Inhibitor (ARI) has achieved worldwide use because of limited efficacy or undesirable side effects. Therefore, evaluating natural sources for ARI potential may lead to the development of safer and more effective agents against diabetic complications. Fifty two Chinese herbal medicines have been investigated for inhibitory activities on AR. Among them, twelve herbal medicines, Artemisia anomala (aerial part), Centella asiatica (aerial part), Scutellaria baicalensis (root), Senecio chrysanthermoides (whole plant), Gleditsia japonica (twig), Zizyphus jujube (twig, leaf), Citrus aurantium (fruit), Hydnocarpus anthelmintica (fruit), Potaninia mongolica (aerial part), Tribulus terrestris (fruit), Artemisia apiacea (aerial part) and Eclipta prostrate (aerial part) exhibited a significant inhibitory activity against AR. Particularly, Artemisia anomala, Centella asiatica and Scutellaria baicalensis showed four times more potent inhibitory activity than the positive control, 3,3-tetramethyleneglutaric acid (TMG).

• Korean Journal of Pharmacognosy
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• v.42 no.2
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• pp.161-168
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• 2011

Advanced glycation end products (AGEs) has been shown to play an important role in the development of the diabetic complications. The AGEs inhibitors or cross-link breakers attenuate various functional and structural manifestations of diabetic complications. In this study, 69 China herbal medicines have been investigated with an in vitro evaluation system using AGEs inhibitory activity. Of these, 28 herbal medicines $IC_{50}$=<50 ${\mu}g/ml$) were found to have stronger AGEs inhibitory activity compared with aminoguanidine ($IC_{50}$=59.77 ${\mu}g/ml$). Particularly, 5 herbal medicines, Camptotheca acuminata (stem, leaf), Eurya groffii (stem, leaf), Cornus Capitata (leaf), Mucuna birdwoodiana (root), Nelumbo nucifera (fruit, seed) showed more potent inhibitory activity (approximately 6-27 fold) than the positive control aminoguanidine.

• Korean Journal of Pharmacognosy
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• v.40 no.1
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• pp.77-81
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• 2009

Abies nephrolepis(Pinaceae) extracts were tested for determined immune system regulating activity based on antiinflammatory activity, antioxidant activity and anti-proliferative effect on HeLa cell line. The A. nephrolepis extracts increased dose-dependently anti-proliferation of HeLa cell line. The DM fraction of the extracts having anti-proliferatative effects of HeLa cell line was fractionalized four subfractions($D1{\sim}D4$). Inflammation-induced NO production was inhibited by D2 and D4 in LPS-activated RAW264.7 macrophages. And also, this fractions showed antioxidant activity examined by DPPH radical scavenging effects. These results suggest that the potential use of DM fraction of A. nephrolepis in chemoprevention and regulation overproduction of NO on pathogenic conditions. The mechanism of the inflammatory effects, however, must be evaluated through various parameters in the induction cascade of NO production.

• Korean Journal Plant Pathology
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• v.14 no.5
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• pp.371-375
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• 1998

Tobacco (Nicotiana tabacum) cultivars including NC 82 and KF 114, and Datura stramonium, Physalis floridana, Gomphrena globosa, and Chenopodium spp. were added to the previous host plants tested for the further examination on the biological characteristics of tobacco mosaic virus (TMV) strains isolated from tobacco (TMV-Common), tomato (TMV-Tomato), and pepper (TMV-Pepper), In TMV-Tomato and TMV-Pepper, different symptoms were noted in P. floridana (no symptom development), and NC 82 (local lesion production on the inoculated leaves) from TMV-Common with which systemic mosaic symptoms were developed. Local lesions were developed in KF 114, D. stramonium, G. globosa, and Chenopodium spp by TMV-Common and TVM-Tomato, while no symptom was observed in KF114 and G. globosa. Also the number and size of local lesions were smaller in KF 114 than Xanthi-nc tobacco (local lesion host) infected with TMV-Tomato. Systemic necrosis was induced in Xanthi-nc and KF 114 when infected with TMV-C at high temperature, but not with the other strains.

• Korean Journal of Plant Tissue Culture
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• v.25 no.5
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• pp.305-308
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• 1998

Leaf and petiole explants of kiwifruit were cultured on MT basal medium supplimented with 2,4-D, kinetin, NAA, and BA. Higher organogenic callus formation was observed on the media with NAA + BA than on the media added with 2,4-D + kinetin. Adventitious buds were formed only on media with NAA and BA. Leaf was better explant than petiole. When callus and adventitious buds were subcultured, shoot formation responsed best on medium with 0.1 mg/L NAA + 2.0 mg/L zeatin. When shoots were cultured on medium with 0.5 mg/L IAA + 0.1 mg/L BA after soaking for 1 hr at IBA solution, rooting was more effective than non-IBA treatment. Rooted shoots developed into normal plants.

• Korean Journal of Plant Tissue Culture
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• v.25 no.5
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• pp.335-339
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• 1998

The factors affecting the isolation and culture of the protoplast of embryogenic callus, derived from immature ovule in Citrus junos, were examined. An incubation time in enzyme solution of 16 hrs was preferable for protoplast isolation. Efficient protoplast yields were obtained from the treatment of equal concentration of 0.7 M $\textrm{BH}_{3}$ to the enzyme solution containing 1.0% cellulase, 1.0% macerozyme and 0.2% pectolyase. Protoplast cultured in MT medium with 0.1 mg/L 2,4-D showed vigorous division and some of them formed callus. Induced callus was subcultured on solid MT medium but the callus showed very slow growth. The above results show the possibility to culture from protoplast fusion in Citrus genera.

• Korean Journal of Environmental Biology
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• v.29 no.1
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• pp.23-30
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• 2011

In this study, the Comet assay (evaluation of DNA damage) used the fish hepatocellular carinoma cell, PLHC-1, was tried to the sediment extract obtained from freshwater to understand its applicability as a tool for monitoring sediment toxicity. In parallel, induced EROD (7-ethoxyresorufin- O-deethylase) activity and DNA damage (TEM values) in PLHC-1 cells were measured for establishing the tandem endpoints of the PLHC-1cell test to test the ecotoxicity of sediment. Among several study sites in a small river passed through downtown and industrial park area, one of them, site B, showed a higher level of EROD activity and DNA damage than other sites. It indicates that a tandem endpoints of PLHC-1 cells could be useful tools for assessing the toxicity of sediment. The sensitivity of Comet assay with PLHC-1 cells was a little higher than that with a blood cell of frog tadpoles to the solvent extract of sediment. According to the results, a PLHC-1 cell-Comet assay could be used as a useful tool for evaluating ecotoxicity of the freshwater sediment. In addition, more detailed studies are needed to the contaminated site.