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        검색결과 172

        22.
        2021.09 KCI 등재후보 구독 인증기관 무료, 개인회원 유료
        Colon cancer has been considered a leading cause of cancer-associated death. Folic acid is a vitamin necessary for cellular physiological functions and cell viability. However, the association between folic acid intake and colon cancer has been examined in several prospective cohort studies are controversial. This study investigated the effects of folate intake on colon carcinogenesis and oxidative stress in an azoxymethane (AOM)/dextran sodium sulfate (DSS) institute for cancer research (ICR) mouse model. Thirty male ICR mice (5 weeks old) were divided into the control group and the experimental group supplied 0.03% folic acid via drinking water (50 mL/week/mouse) for 6 weeks. To induce colonic pre-neoplastic lesions, the animals were subcutaneously injected three times weekly with AOM (10 mg/kg body weight), followed by 2% DSS in drinking water for a week. Folic acid supplementation significantly suppressed the total number of aberrant crypt foci and aberrant crypts. Histological image data showed that folic acid supplementation attenuated neoplastic change. In addition, we measured the thiobarbituric acid reactive substances concentration of dry feces samples to identify the effect of folic acid on reactive oxygen accumulation. The folic acid supplementation group had reduced reactive oxygen species levels in dry feces compared to the control group. In conclusion, these findings indicate that folic acid suppresses colon carcinogenesis and oxidative stress in an AOM/DSS mouse model.
        4,000원
        23.
        2021.06 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        In the dismantling process of a reactor coolant system (RCS) piping, a radiation protection plan should be established to minimize the radiation exposure doses of dismantling workers. Hence, it is necessary to estimate the individual effective dose in the RCS piping dismantling process when decommissioning a nuclear power plant. In this study, the radiation exposure doses of the dismantling workers at different positions was estimated using the MicroShield dose assessment program based on the NUREG/CR-1595 report. The individual effective dose, which is the sum of the effective dose to each tissue considering the working time, was used to estimate the radiation exposure dose. The estimations of the simulation results for all RCS piping dismantling tasks satisfied the dose limits prescribed by the ICRP-60 report. In dismantling the RCS piping of the Kori-1 or Wolsong-1 units in South Korea, the estimation and reduction method for the radiation exposure dose, and the simulated results of this study can be used to implement the radiation safety for optimal dismantling by providing information on the radiation exposure doses of the dismantling workers.
        4,200원
        26.
        2021.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구는 최고경영자 승계(CEO succession) 분야에서, 가족경영자(family CEO)로부터 전문경영자 (professional CEO)로의 승계과정에 초점을 맞춘다. 가족경영자에서 전문경영자로의 최고경영자 승계 (F-P succession)는 대리인문제를 야기할 가능성을 내포하고 있다. 그럼에도 불구하고 F-P 승계는 일반적으로 일어나는 최고경영자 승계의 유형이므로, 예상되는 대리인문제에 대한 처방으로 가장 먼저 생각 할 수 있는 방안은 대리인이론에 제시하는 사외이사제도와 같은 내부통제메커니즘이다. 같은 맥락에서 한국기업에는 1997년 외환위기 이후 사외이사제도가 법제화 되었다. 그러나 한국의 상황은 대리인이론이 가정하는 것과 차이점을 보이고 있다. 대리인이론의 출발점인 소유와 경영의 분리와는 달리, 한국기업은 기업을 소유하고 있는 지배주주일가의 가족구성원이 최고경영자로서 해당 기업의 경영도 맡고 있는 형태인 가족경영자인 경우가 일반적으로 관찰된다. 이와 같은 상황에서 F-P 승계로 인한 대리인문제에 대하여, 전제에서 차이를 보이는 대리인이론에 입각한 사외이사제도가 과연 내부통제메커니즘으로서 원활하게 작동할 것인가에 대해서 고찰할 필요가 있다. 기존 연구에 따르면, 한국 기업에서 이사회에 포함된 지배주주일가의 가족임원은 최고경영자에 대한 감시 및 견제의 기능을 하고 있다. 따라서, 본 연구는 대리인문제가 발생할 수 있는 F-P 승계에 있어서, 대리인이론에 입각한 사외이사제도가 감시기능(monitoring function)을 수행하지 못할 것이고, 오히려 이 사회의 가족임원(family member in BOD)이 내부통제메커니즘으로서 작동할 것으로 기대한다. 실증결과, 사외이사제도에서 규정한 사외이사의 수를 초과하여 선임한 사외이사의 수는 F-P 승계에 유의한 영향을 미치지 못하는데 반해, 이사회 내에 가족임원의 여부는 F-P 승계에 유의한 정(+)의 영향을 미치는 것을 확인하였다.
        4,300원
        27.
        2020.12 KCI 등재후보 구독 인증기관 무료, 개인회원 유료
        Colon cancer is known as the third most widespread cancer in the world. The interaction of heme-iron and ascorbic acid (AA) in colon carcinogenesis is not evident. Hemin (ferric chloride heme) is an iron-containing porphyrin with chlorine that can be formed from a heme group. The purpose of this study was to investigate the protective effect of AA on the formation of pre-neoplastic lesions induced by azoxymethane (AOM)/dextran sodium sulfate (DSS) plus hemin in mice. Forty-five ICR male mice were divided into three experimental groups; AOM/ DSS treatment (control group), hemin (2 g hemin/kg of b.w.), hemin + AA (1.0% in drinking water). The mice had three s.c. injections (0–2nd weeks of the experiment) of AOM (10 mg/kg b.w.) weekly and 2% DSS as drinking water for the next one week and the animals fed on AIN-76A purified rodent diet for 6 weeks. The numbers of aberrant crypt foci (ACF) and aberrant crypts (ACs) in colonic mucosa were counted after methylene blue staining. Lipid peroxidation in feces was measured by the thiobarbituric acid-reactive substances (TBARS) assay. The numbers of ACF and ACs per colon significantly increased in Hemin group compared to the control group. However, the numbers of ACF and ACs per colon notably decreased in hemin + AA group compared to the control group or hemin group (p<0.05). In feces, the TBARS value of hemin group was higher than the control group (p<0.01). The TBARS value of hemin + AA group was slightly decreased compared to Hemin group. These results indicate that hemin can promote the experimental colon carcinogenesis in ICR mice. On the other hand, additional supplement of AA via drinking water has a protective effect against the colon carcinogenesis. The related mechanisms need to be illustrated by further studies in future.
        4,000원
        28.
        2020.12 KCI 등재후보 구독 인증기관 무료, 개인회원 유료
        Globally, colon cancer is increased gradually and known as one of the major causes of cancer death. Stevia, a substitute of sugar, is known to have many components including alpha-tocopherol and anthocyanin etc, as antioxidants. This study's purpose is to investigate whether stevia plant extract can have a protective effect against colon carcinogenesis induced by azoxymethane (AOM) and dextran sodium sulfate (DSS) in mice. Total 30 male ICR mice were divided into 2 groups; AOM/DSS treatment (control group), AOM/DSS + stevia extract (0.5%, in drinking water). After acclimation for 1 week, five weeks old mice received three intraperitoneal AOM (10 mg/kg b.w.) injections weekly for 3 weeks (0–2nd weeks of the experiment) and 2% DSS as drinking water for the next one week. AIN-76A purified rodent diet and 0.5% stevia extract water were supplied to the animals for 6 weeks. The colons of mice were collected and the number of aberrant crypt foci (ACF) and aberrant crypts (ACs) in colonic mucosa were counted after staining with methylene blue. Malondialdehyde (MDA) concentration in feces were determined. The numbers of ACF and ACs were significantly (p<0.01) decreased in stevia-treated group compared with the control group. The MDA concentration in feces was also significantly (p<0.01) decreased in stevia-treated group compared with the control group. In histopathology of colonic epithelium, hyperplasia of colonic epithelium was less observed in steviatreated group. These results indicate that stevia has a protective effect against colon carcinogenesis induced by AOM/DSS in mice and further study needs to illustrate the protective mechanisms.
        4,000원
        30.
        2020.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        There is a growing global interest in food choices that could affect health. Consumer food choices are dictated by numerous factors such as attitudes, beliefs, desires and preferences stemming from psychological and physiological attributes. The present study aimed to understand consumers’ internal perceptions about cream soup, cream sauce, and tomato sauce using ZMET (Zaltman’s Metaphor Elicitation Technique). The 9 step ZMET interview process was conducted for a sample of 36 consumers (12 consumers for each sauce). A content analysis of the survey results was carried out. From this, 56 concepts of cream soup were derived, and 15 constructs that met with the agreement of more than one-third of the total sample consumers were extracted. These 15 constructs included ‘Soft’, ‘Recollection’, ‘Familiar’, ‘Warm’, ‘Comfortable’, etc. Similarly, for cream sauce, 67 concepts and 20 constructs ‘Silky’, ‘Warm’, ‘Restaurant’, ‘Family’, ‘Memory’, etc. were deduced. A total of 66 concepts and 20 constructs for tomato sauce ‘Sourness’, ‘Sauce Bottle’, ‘Pleasant’, ‘Ingredient’, ‘Cooking’, etc. were derived. The analysis of consumers’ consensus maps through this study provides a deep and useful understanding of consumers and their latent needs. Also, the results of this study indicate that exploring consumers’ internal perceptions is critical to understanding their healthy food choices. This can be used as basic data for formulating marketing strategies.
        4,000원
        34.
        2020.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        A eukaryotic marine microalga was isolated from Jungmun Saekdal Beach, Jeju Island, Korea and an integrated approach, including molecular phylogeny and morphology, was used to determine its taxonomical status. Molecular phylogenetic evidence inferred from the small subunit (SSU) 18S rRNA sequence and internal transcribed spacer (ITS) secondary structure analysis clearly showed that the isolate belonged to the recently described species, Jaagichlorella roystonensis. Distinctive morphological keys of the species were also observed by light microscopy and scanning/ transmission electron microscopy (S/TEM). In this study, a Korean marine J. roystonensis species was described for the first time and was subsequently added to the national culture collections in Korea.
        4,000원
        35.
        2020.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Partheno Embryo's research is known to play a very important role in identifying the development of embryonic cells or analyzing the genetic mechanisms of embryonic development, but the information on apoptosis formed during the early stage of development on Partheno Embryo is very little. Therefore, this study analyzed whether the embryonic cell death of unit embryos can be inhibited by adding Scriptaid, one of HDACi, which plays a role in demethylation of histone proteins as a method of regulating the cell cycle in the early embryo development of Partheno Embryo. As a result, the differentiation rate was higher in the group that added Scriptaid and FBS, but the cellular development was higher in the group that added pregnant serum to Scriptaid. As a result of analyzing the expression of the gene through IF and PCR, the group with the addition of gestational serum increased the expression of BCL2 and PCNA, which affects the anti-Casp3 action in cell survival. In addition, it is interpreted that treatment of Scriptaid for 16 hours, rather than 24 h treatment lowers the expression of Casp-3, a representative factor of apoptosis, and also increases embryonic development, thus affecting early embryo development. Therefore, it is concluded that the 16-hour treatment of Scriptaid and the use of gestational serum will inhibit cell death in the early embryonic development and increase the development rate of the embryo.
        4,000원
        37.
        2020.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In the early development of parthenogenetic embryo, cytoplasm and nucleic acid fragmentation may be a cause of lower embryo development. The purpose of this study was to evaluate whether embryonic development and apoptosis factors can be reduced by controlling the in-vitro culture environment by the addition of hormones, pregnancy serum and uterine milk. Our study showed that the activity of Casp-3 increased within the cytoplasm when artificially used hormones to induce the incubation environment, and PCNA's manifestation was low. However, the addition of pregnant serum appeared to lower the Casp-3 activity compared to the other groups. In addition, MMP-9 activity was increased and early embryo development and cytoplasmic fidelity were also increased. Therefore, the results of the present study showed that the use of gestational serum in the development of parthenogenetic embryo inhibit apoptosis and increases cytoplasmic reorganization by natural environmental control in in vitro culture.
        4,000원
        38.
        2020.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        A eukaryotic microalga was isolated from seawater in Janghang Harbor, Korea and its morphological, molecular, and physiological characteristics were investigated. Due to its simple morphology, no distinctive characters were found by morphological observation, such as light microscope or scanning/transmission electron microscopy (S/ TEM). However, molecular phylogenetic evidence inferred from the concatenated small subunit (SSU) 18S rRNA and internal transcribed spacer (ITS) sequence data indicated that the isolate belonged to the newly described Micractinium singularis. Furthermore, it was clustered with Antarctic Micractinium strains and it also showed a psychrotolerant property, surviving at temperatures as low as 5°C. However, its optimal growth temperatures range from 15°C to 25°C, indicating that this microalga is a mesophile. Additionally, gas chromatography-mass spectrometry (GC/MS) analysis showed that the isolate was rich in nutritionally important omega-3 polyunsaturated fatty acid, and high-performance liquid chromatography analysis (HPLC) revealed that the high-value antioxidant lutein was biosynthesized as an accessory pigment by this microalga, with glucose as the major monosaccharide. Therefore, in this study, a Korean marine M. singularis species was discovered, characterized, and described. It was subsequently added to the national culture collections.
        4,000원
        39.
        2020.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In this study, we investigated whether infusion of colorectal cancer cell line and PMSG could increase endometrial cancer. As a result, our study confirmed that the injection of colorectal cancer can cause inflammation and cancer in the uterus and increase the VEGF gene in the uterus. The study also found that endometrial cancer was associated with PMSG.
        4,000원
        40.
        2019.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Potential utility of 14 candidate housekeeping genes as normalization reference for RT-qPCR analysis with developmental samples (fertilized eggs to late veliger larvae) in Pacific abalone Haliotis discus hannai was evaluated using four different statistical algorithms (geNorm, NormFinder, BestKeeper and comparative ΔCT method). Different algorithms identified different genes as the best candidates, and geometric mean-based final ranking from the most to the least stable expression was as follow: RPL5, RPL4, RPS18, RPL8, RPL7, UBE2, RPL7A, GAPDH, RPL36, PPIB, EF1A, ACTB and B-TU. The findings were further validated via relative quantification of metallothionein (MT) transcripts using the stable and unstable reference genes, and expression levels of MT were greatly influenced according to the choice of reference genes. In overall, our data suggest that RPL5 and RPS18, either singly or in combination, are appropriate for normalizing gene expression in developmental samples of this abalone species, whereas ACTB, B-TU and EF1A are less stable and not recommended. In addition, our findings propose that standard deviations in geometric ranking as well as geometric mean itself should also be taken into account for the final selection of reference gene(s). This study could be a useful basis to facilitate the generation of accurate and reliable RT-qPCR data with developmental samples in this abalone species.
        4,300원
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