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        검색결과 237

        41.
        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
        42.
        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
        44.
        2020.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study was conducted at the National Institute of Animal Science from 2010 to 2017. As a variety that is sufficiently productive in the southern regions to replace imported varieties and sufficiently cold-resistant to be cultivated in the central-northern regions, "IR605" was developed and submitted to the Korea Seed & Variety Service in an application for protection. The novel Italian ryegrass variety "IR605" is a diploid with green leaves, a semi-erect growth habit before wintering, and an erect growth habit in the spring. "IR605" was a medium maturing variety with a heading date of around May 15th. "IR605" had a flag leaf width of 9.9 mm, flag leaf length of 26.7 cm, and plant length on the heading date of 100 cm, which was approximately 5 cm longer than "Kowinearly." The stem thickness and ear length of "IR605" are 0.08 mm thicker and 0.5 cm longer than those of "Kowinearly", respectively. The cold-resistance of "IR605" was weaker than that of "Kowinearly", but strong enough to be cultivated in Pyeongchang, Gangwon province. The dry matter yield of "IR605" (9,308 kg/hectare) was 20% higher than that of "Kowinearly", which was further pronounced in the southern region of Haenam, where there was a 52% increased (p < 0.05). The in vitro dry matter digestibility of "IR605" was 68.4% at which was slightly higher than that of "Kowinearly", The total digestible nutrients was 58.5%, which was slightly lower than "Kowinearly". Overall, the feed quality characteristics of "IR605" were similar to those of "Kowinearly".
        4,000원
        46.
        2019.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        모바일 MMORPG는 게임 시장을 주도하고 있고 더욱 발전할 것이다. 많은 게임의 출시에도 불구하고 UI등 디자인설계 요인에서부터 소프트웨어 품질요인까지의 종합적인 MMORPG 설계연구가 부족한 상황에서 사용자들이 원하고 선호하는 세부 설계요인을 찾는 것은 매우 중요하다. 본 연구는 모바일 MMORPG의 사용자와 개발자가 객관적인 시각에서 양자가 만족하는 핵심적이고 중요한 게임 설계 요인을 찾고자 시도되었다. 실증분석은 이론적인 연구들을 기반으로 모바일 MMORPG 설계 요인들 3단계로 계층화하여 그 중요도는 계층분석과정(AHP)을 통해 검증하였다. 설계 요인의 중요도는 재미 요인, 구성 요인, UI 요인, 시스템 요인, 환경 요인 순이고 재미의 중요성에서는 도전 재미가 가장 중요하며 도전 재미에서는 보상이 중요하다는 결과를 얻었다. 재미 요인 중에서 새롭게 추가한 우월성이나 대결성을 포함하는 경쟁 재미가 다양성, 탐험성을 포함한 상상 재미보다 높게 나온 다. 이는 수많은 사용자가 길드, 혈맹, 진영 종족단위로 경쟁하고 협동하며 즐기는 모바일 MMORPG의 특성을 반영한 것으로 생각된다. 본 연구는 MMORPG 설계 요인들을 분석 추출 하였으며 중요도를 파악하여 모바일 MMORPG 설계 능력 향상에 기여할 것으로 생각한다.
        4,200원
        51.
        2019.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Salicylic acid (SA) is an essential plant growth regulator that functions as a signaling molecule in plants. The purpose of this study was to clarify how the exogenous application of SA counteracts aluminum stress-induced growth and biomass yield reduction in alfalfa exposed to aluminum (Al) stress. Two-week-old alfalfa seedlings were exposed to a combination of AlCl3 (0 μM, 50 μM and 100 μM, respectively) and SA (0.1 mM) for 72 hours. We observed, Al stress-induced plant growth inhibition and forage yield reduction are Al stress-dependent manner. A significant reduction of plant height (42.0-52.9%), leaf relative water content (13.0-21.4%), root length (35.4-48.7%), shoot fresh weight (31.2-25.9%), root fresh weight (15.4-23.3%), shoot dry weight (12.7-22.2%), roots dry weight (47.3 -53.5%), were observed in alfalfa. In contrast, SA alleviated the Al-stress and enhanced growth and biomass yield in alfalfa. This study provides useful information concerning the role of SA that counteracts aluminum stress-induced growth and yield reduction in alfalfa.
        4,000원
        52.
        2019.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Calcifying Epithelial OdontogenicTumor(CEOT), also known as Pindborg tumor is a rare lesion comprising about 1% of all odontogenic tumors mostly rising in the posterior of the mandible. It generally occurs in patients between 30-60 years old. This paper describes a case of CEOT in a 17 year-old female affecting the right mandible. Histopathologic findings showed sheets of polygonal tumor cells and pools of amorphous, eosinophilic amyloids with calcifications. 1 year after resection of the tumor, no clinical and radiographic signs of recurrence were observed.
        3,000원
        53.
        2019.05 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The wakes behind a square cylinder were simulated using two-equation turbulence models, k-ε and RNG k-ε models. For comparisons between the model predictions and analytical solutions, we employed three skill assessments:, the correlation coefficient for the similarity of the wake shape, the error of maximum velocity difference (EMVD) of the accuracy of wake velocity, and the ratio of drag coefficient (RDC) for the flow patterns as in the authors’ previous study. On the basis of the calculated results, we discussed the feasibility of each model for wake simulation and suggested a suitable value for an eddy viscosity related constant in each turbulence model. The k-ε model underestimated the drag coefficient by over 40 %, and its performance was worse than that in the previous study with one-equation and mixing length models, resulting from the empirical constants in the ε-equation. In the RNG k-ε model experiments, when an eddy viscosity related constant was six times higher than the suggested value, the model results were yielded good predictions compared with the analytical solutions. Then, the values of EMVD and RDC were 3.8 % and 3.2 %, respectively. The results of the turbulence model simulations indicated that the RNG k-ε model results successfully represented wakes behind the square cylinder, and the mean error for all skill assessments was less than 4 %.
        4,000원
        54.
        2019.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Excessive intake of red meat has been associated with colon carcinogenesis. The effect of hemin and zinc on colon carcinogenesis was investigated in male ICR mice. After acclimation for 1 week, five-week-old mice received three s.c. injections (0-2nd weeks of the experiment) of azoxymethane (AOM; 10 mg/kg b.w.) weekly and were treated by 2% dextran sodium sulfate (DSS) in drinking water for the next 1 week to induce aberrant crypt foci (ACF). Mice were fed on AIN-76A purified rodent diet for 6 weeks. There were three experimental groups; control, hemin, and hemin + zinc groups. The daily oral doses of hemin and zinc were 534 mg/kg and 55 mg/kg b.w., respectively. After staining colonic mucosa with 0.2% methylene blue, the ACF, aberrant crypts (AC), and polyps were counted. Lipid peroxidation in liver was evaluated by thiobarbituric acid-reactive substances (TBARS) assay. The numbers of AC, ACF, large ACF (i.e., ≥4 AC/ACF), and polyps in the hemin group were higher than those in the control group. In hemin + zinc group, the numbers of AC, ACF, large ACF were significantly lower compared to the hemin or control groups (p < 0.05), and the number of polyps was also significantly lower compared to that in the hemin group (p < 0.05). The TBARS level in the livers of the hemin + zinc group was significantly lower than that of the hemin group (p < 0.05). These results suggest that hemin enhances colon carcinogenesis and that co-treatment with zinc can protect against the induction of colon carcinogenesis.
        4,000원
        55.
        2018.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        1. 본 연구는 한국 재래종 강낭콩 209자원의 phytochemical 및 항산화활성을 평가하였다. 2. 항산화활성은 DPPH, ABTS, FRAP, SOD를 분석하였으며 phytochemical은 kaempferol, myricetin, quercetin, naringenin 함량을 각각 분석하였다. 3. 항산화활성은 강낭콩 자원 간 다양한 분포를 보였으며 DPPH의 경우 62.3~643.9 (IC50), ABTS의 경우 0.28~1.49 mgAAE/g, FRAP의 경우 0.41~5.44 mgAAE/g, SOD의 경우 50.4 ~ 299.8 (IC50)로 나타났다. 4. Relative antioxidant capacity index (RACI)로 강낭콩 자원의 항산화활성을 비교한 결과 IT104587이 가장 높은 항산화활성을 보였으며 IT189598이 가장 낮은 항산화활성을 보였다. 5. 분석된 Phytochemical 중에서 한국 재래종 강낭콩에서는 Kaempferol이 가장 높은 함량을 나타냈다. 6. PCA 분석 결과 209자원은 3개의 그룹으로 나뉘었으며 이중 그룹 III에 속한 46자원의 강낭콩이 낮은 항산화활성 및 phytochemical 함량을 보였다. 7. 본 연구 결과는 한국 재래종 강낭콩의 항산화활성 및 phytochemical 정보를 제공하며 이 정보는 강낭콩 품종 개발을 위한 기초 정보로 사용될 수 있을 것이다.
        4,500원
        56.
        2018.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Clostridium perfringens (C. perfringens) may cause diarrhea and enterotoxemia in adult and young livestock, leading to problems in the production and management of farms. Four hundred fecal samples were collected from 25 goat farms located in Gyeongsangbuk-do Province in the Republic of Korea. Sixteen C. perfringens strains were isolates from fecal samples, and the isolates were identified as type A (n=11) and type D (n=5). Additionally, α- and ε-toxin genes were detected in 16 and 5 strains by PCR, respectively, and the enterotoxin gene was presented in 2 strains. The antibiotic susceptibility test was performed using the disk diffusion method and E-test method. In the disk diffusion method, ampicillin (n=16) and chloramphenicol (n=15) were highly susceptible to 16 C. perfringens isolates. In the E-test method, ampicillin, amoxicillin, amoxicillin/clavulanic acid and meropenem were susceptible to more than 14 of 16 C. perfringens isolates. This study indicates that administration of antibiotics such as ampicillin, amoxicillin/clavulanic acid and meropenem can prevent and treat C. perfringens infections in goats.
        4,000원
        57.
        2018.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study investigated the characteristics of obesity induced by a high-fat diet (HD) over 13 weeks in Rhbdf2 gene knockout (KO) mice. Forty 7-week-old Rhbdf2 wild and KO mice were used and the mice were divided into 4 groups: Wild-ND (n=10, Rhbdf2 wild mice, normal diet (ND)), Wild-HD (n=10, Rhbdf2 wild mice, HD), KO-ND (n=10, Rhbdf2 KO mice, ND) and KO-HD (n=10, Rhbdf2 KO mice, HD). The relative epididymal fat weight in KO-HD was significantly increased compared with that in KO-ND (P<0.01). The relative liver and spleen weights in KO-HD were decreased compared with those in Wild-HD (p < 0.05) and KO-ND (p < 0.01). The mRNA expression of SOD1 in KO-ND was significantly reduced compared with that in Wild-ND (p < 0.05). In Wild-ND and HD, the mRNA expressions of TNF-α and IL-6 in epididymal fat were significantly increased compared with those in KO-ND and HD (p < 0.01). A significant increase of TNF- α and IL-6 mRNA expression was observed in KO-HD compared with KO-ND (p < 0.01). These results indicated that Rhbdf2 genes may regulate high fat diet-induced obesity damage by anti-inflammatory and anti-oxidative roles in fat tissue of mice.
        4,000원
        60.
        2018.10 구독 인증기관·개인회원 무료
        후각 신경 시스템은 일반 생활 환경에서 많은 다양한 화학 물질을 인식하고 구별한다. 곤충에서는 다양한 화학 물질을 기호적 또는 회피적인 특이성을 부여하고 이를 구분해 낼 수 있는 고도로 발달된 후각신경 수용체들로 구성된 냄새 맡는 (odorant-gated) 이온 채널 군을 진화시켰다. 최근에 후각 수용체와 단백질을 포함한 olfaction 관련한 진딧물 게놈 밝혀졌고, 초파리에서 다양하게 분화되어 있는 후각 수용체들이 보고되고 있다. 후각 신경 수용체의 유전체는 매우 높은 보전적인 염기 서열을 가지고 있으며, 체계적인 신호 전달 시스템을 갖추고 있다. 대표적 수용체인 odorant-gated ion channels comprised of a highly conserved co-receptor (Orco)는 중심 구멍 주위에 대칭 적으로 배열된 4 개의 서브 유닛을 갖는 homotetramer 채널 구조를 가지고 있다. 이는 인체 내에 존재하는 7-transmembrane receptor와 매우 유사한 구조를 형성하고 있고, 신경전달물질의 수용체와 매우 유사한 구조적 형태 및 gating mechanism을 가지고 있다. 본 연구에서는 초파리에서 분리한 후각 신경 수용체 하위 유형인 OR65 유전자 분리하여 세포 발현 시켜 Xenopus oocyte를 이용하여 Whole cell voltage clamp recording을 실시하였다. 본 수용체의 성공적인 발현 이후 유해 해충 유인제 개발 회사인 마이크로자임의 미생물 배양 추출물을 이용해서 후각 신경 수용체 활성 조절 여부를 연구하였다. 미생물 배양 추출물을 10,000배 희석한 recording media에서 수용체의 활성을 확인하였고, 이를 농도 별로 처리하여 농도 의존성 수용체 활성 작용을 확인하였다. 따라서 곤충의 후각 신경 수용체 활성 조절 시스템을 이용하여 유인물질 또는 기피 물질을 발굴할 수 있으며, 본 연구를 통해서 MZ01은 곤충 수용체 OR65를 활성 시킴으로써 유인 현상을 나타내며, 본 연구를 통해서 현장에서 검증된 미생물 배양 추출물의 성능을 과학적 분석으로 결과를 제시하였다.
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