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        검색결과 8

        2.
        2012.12 구독 인증기관 무료, 개인회원 유료
        To evaluate the acute to chronic effects of crude oil exposure on hematological and blood biochemical toxicities, Sprague-Dawley rats were given oral doses of 0, 50, or 100 mg/kg BW/day of Iranian heavy crude oil for a period of four weeks. In the acute phase of exposure (one day after four weeks of oil treatment), decreases in weight of thymus, serum level of interferon gamma (IFN-γ), superoxide dismutase (SOD), and catalase activities in liver or kidney, and increase in weight of adrenal gland occurred after oral administration of crude oil. In body weight, histopathological examination, hematological and blood biochemical analyses in the acute phase of exposure, no significant differences were observed among the experimental groups. In the subchronic and chronic phase of exposure (two months and six months after four weeks of oil treatment), the changes of biomarkers were normalized, except the indicators of oxidative stress. Our findings showed that the bioassay on the indicators of oxidative stress is a sensitive method for determining exposure to crude oil in rats.
        4,000원
        3.
        2011.10 구독 인증기관·개인회원 무료
        A total of 5,000 ethanolic and methanolic extracts of different plant species from 23 nations including Costa Rica, Vietnam, Philippines, India, South Africa, Pakistan and Peru were evaluated for their larvicidal activities against Aedes aegypti, the major vector of dangue, dangue hemorhagic fever and yellow fever. The larval mortalities were observed 24h after treating the larvae to the extracts. At 500 ppm, 179 extracts showed >80% larval mortality in the 24h exposure. Among the extracts tested, the highest larval mortality was observed in the extracts of Piper guianense, Piper nigrum, Piper mocropodum, Piper sem-immersum, Piper magen and Piper pubicatulum. The LC50 value of extract P. guianense, P. nigrum, P. mocropodum, P. sem-immersum, P. magen and P. pubicatulum were 8.84, 11.48, 8.84, 13.86, 9.48 and 10.12 ppm against Ae. aegypti. It is suggested that P. guianense, P. nigrum, P. mocropodum, P. sem-immersum, P. magen and P. pubicatulum can be developed as potent larvicidal agents against Ae. aegypti.
        4.
        2019.05 KCI 등재 SCOPUS 서비스 종료(열람 제한)
        The study aims to investigate the effects of brand value in the oriental medicine cosmetics market, as perceived by consumers, on brand satisfaction, brand loyalty, and purchase intention. The subjects were Korean and Chinese female consumers, the primary consumers of oriental medicine cosmetics. A total of 615 sample surveys were analyzed from consumers who have experience using oriental medicine cosmetics. Out of the sample, 264 respondents had used Oriental medicine cosmetics for one to four years, 199 respondents for more than four years, and 108 respondents for three months to a year. Based on existing research, we categorized the value of oriental medicine cosmetics brands into four dimensions: emotional, social, functional, and epistemic values. Whether brand satisfaction and brand loyalty can be mediating factors in brand value influencing purchase intention was inspected through several hypotheses. As a result, except for the epistemic value factor, the brand value factors were found to have a positive effect on brand satisfaction and brand loyalty. In addition, emotional, social, and functional brand value factors influence purchase intention through brand loyalty, and it was found that brand loyalty is an important factor for oriental medicine cosmetics consumers, however mediator effects did not appear for brand satisfaction.
        5.
        2019.03 KCI 등재 SCOPUS 서비스 종료(열람 제한)
        Being a torque free motion of the rotating Earth, Chandler wobble is the major component in the Earth’s polar motion with amplitude about 0.05-0.2 arcsec and period about 430-435 days. Free core nutation, also called nearly diurnal free wobble, exists due to the elliptical core-mantle boundary in the Earth and takes almost the whole part of un-modelled variation of the Earth’s pole in the celestial sphere beside precession and nutation. We hereby present a brief summary of their theories and report their recent features acquired from updated datasets (EOP C04 and ECMWF) by using Fourier transform, modelling, and wavelet analysis. Our new findings include (1) period-instability of free core nutation between 420 and 450 days as well as its large amplitude-variation, (2) re-determined Chandler period and its quality factor, (3) fast decrease in Chandler amplitude after 2010.
        6.
        2010.09 KCI 등재 서비스 종료(열람 제한)
        A neurotoxin, 6-hydroxydopamine (6-OHDA) has been widely used to create animal model for Parkinson's disease (PD). The present study was undertaken to examine whether depletion of brain dopamine (DA) stores with 6-OHDA can make alteration in the activities of the testicular steroidogenesis in adult rats. Young adult male rats (3 months old) were received a single dose of 6-OHDA (200 in 10 /animal) by intracerebroventricular (icv) injection, and sacrificed after two weeks. The mRNA levels of steroidogenesis-related enzymes were measured by qRT-PCRs. Serum testosterone levels were measured by radioimmunoassay. Single icv infusion of 6-OHDA significantly decreased the mRNA levels of CYP11A1 (control:6-OHDA group= AU, p<0.05), CYP17 (control:6-OHDA group= AU, p<0.05). There were no changes in the mRNA levels of -HSD (control:6-OHDA group= AU) and -HSD (control: 6-OHDA group= AU), though the levels tended to be decreased in the 6-OHDA treated group. Administration of 6-OHDA decreased significantly the mRNA level of StAR when compared to the level of saline-injected control animals (control:6-OHDA group= AU, p<0.05). Treatment with single dose of 6-OHDA remarkably lowered serum testosterone levels compared to the levels of control group (control:6-OHDA group=, p<0.05). Taken together with our previous study, the present study demonstrated that the activities of hypothalamus-pituitary-testis hormonal axis could be negatively affected by blockade of brain DA biosynthesis, and suggested the reduced reproductive potential might be resulted in the animals. More precise information on the testicular steroidogenic activities in PD patients and PD-like animals should be required prior to the generalization of the sex steroid hormone therapy to meet the highest standards for safety and efficacy.
        7.
        2009.09 KCI 등재 서비스 종료(열람 제한)
        In mammals, puberty is a dynamic transition process from infertile immature state to fertile adult state. The neuroendocrine aspect of puberty is started with functional activation of hypothalamus-pituitary-gonadal hormone axis. The timing of puberty can be altered by many factors including hormones and/or hormone-like materials, social cues and metabolic signals. For a long time, attainment of a particular body weight or percentage of body fat has been thought as crucial determinant of puberty onset. However, the precise effect of high-fat (HF) diet on the regulation of hypothalamic GnRH neuron during prepubertal period has not been fully elucidated yet. The present study was undertaken to test the effect of a HF diet on the puberty onset and hypothalamic gene expressions in immature female rats. The HF diet (45% energy from fat, HF group) was applied to female rats from weaning to around puberty onset (postnatal days, PND 22-40). Body weight and vaginal opening (VO) were checked daily during the entire feeding period. In the second experiment, all animals were sacrificed on PND 36 to measure the weights of reproductive tissues. Histological studies were performed to assess the effect of HF diet feeding on the structural alterations in the reproductive tissues. To determine the transcriptional changes of reproductive hormone-related genes in hypothalamus, total RNAs were extracted and applied to the semi-quantitative reverse transcription polymerase chain reaction (RT-PCR). Body weights of HF group animals tend to be higher than those of control animals between PND 22 and PND 31, and significant differences were observed PND 32, PND 34, PND 35 and PND 36 (p<0.05). Advanced VO was shown in the HF group (PND p<0.001) compared to the control (PND ). The weight of ovaries (p<0.01) and uteri (p<0.05) from HF group animals significantly increased when compared to those from control animals. Corpora lutea were observed in the ovaries from the HF group animals but not in control ovaries. Similarly, hypertrophy of luminal and glandular uterine epithelia was found only in the HF group animals. In the semi-quantitative RT-PCR studies, the transcriptional activities of KiSS-1 in HF group animals were significantly higher than those from the control animals (p<0.001). Likewise, the mRNA levels of GnRH (p<0.05) were significantly elevated in HF group animals. The present study indicated that the feeding HF diet during the post-weaning period activates the upstream modulators of gonadotropin such as GnRH and KiSS-1 in hypothalamus, resulting early onset of puberty in immature female rats.
        8.
        1997.10 KCI 등재 서비스 종료(열람 제한)
        Indica 벼의 원형질체들로 부터 효과적인 식물체 재분화 방법을 개발하였다. 이 방법은 배형성 진탕 세포 배양체로 부터 나출된 원형질체들을 feeder cell들이 agarose에 embedded된 배지 표면에 놓인 filter membrane 위에 배양하는 것이다. Feeder cell로서 Lolium multiflorum 세포배양체를 사용했을 때가 Oryza ridleyi를 사용했을 때보다 효과적이었고, 원형질체 평탄효율은 세포 배양체 age에 따라 달랐지만 최고로 0.68% 까지 증가되었다. Carbohydrate source로서 maltose를 사용하거나 maltose와 sucrose를 1:1로 조합했을 때가 sucrose 단독으로 사용했을 때보다 식물체 재분화율이 증가되었고, 고농도의 agarose를 이용하여 원형질체로부터 유도된 캘러스를 dehydration시켰을 때 또한 재분화율이 괄목하게 증가되었다. 식물체 재분화율은 control 캘러스로부터 3.1∼30.6% 였지만 dehydration처리한 캘러스로부터는 30.7∼70.7%까지 증가되었다. 원형질체로 부터 유도된 식물체들은 형태적으로 정상이며 개화했다.