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        검색결과 308

        81.
        2018.09 구독 인증기관·개인회원 무료
        Cold, salt and heat are most critical factors that restrict full genetic potential, growth and development of crops worldwide.. In this study, we applied an annealing control primer (ACP) based GeneFishing approach to identify differentially expressed genes (DEGs) in annual ryegrass (cv. Kowinearly) leaves under cold, salt and heat stresses. Two-week-old seedlings were exposed to cold (4°C), salt (NaCl 200 mM) and heat (42 °C) treatments for 6 h. A total 8 differentially expressed genes were isolated form ryegrass leaves. These genes were sequenced then identified and validated form National Center for Biotechnology Information (NCBI) database. We identified several promising genes encoding light harvesting chlorophyll a/b binding protein, alpha-glactosidase b, chromosome 3B, elongation factor 1-alpha, FLbaf106f03, complete genome, translation initiation factor SUI1, and glyceraldehyde-3-phosphate dehydrogenase. These genes were potentially involved in photosynthesis, plant development, protein synthesis and abiotic stress tolerance in plants. These genes might be useful for the enhancement of abiotic stress tolerance in fodder crops along with crop improvement under unfavorable environmental conditions.
        82.
        2018.05 구독 인증기관·개인회원 무료
        The objective of this study was to evaluate the effectiveness of various crack inducers to be used in the advanced reinforced concrete pavement (ARCP) by conducting yard tests. Some of cracks are induced in ARCP to reduce the stresses in steel bars and to form more uniformly spaced cracks so that the required steel bar amount can be decreased and at the same time the pavement performance can be improved. In this study, an experimental ARCP was constructed for the length of 22.4 m, width of 1.12 m, and thickness of 0.26 m. The anchor lugs were placed at both ends of ARCP to pretend continuities of the system. 8 crack inducers with a uniform spacing of 2.8 m were installed in different manners when placing concrete, so the test length of the experimental ARCP was 19.6 m. The variables of crack inducers included the shape, material, installed depth, and installing method. The basic shape of the crack inducer represented a round face and a flat opposite face with a height of 50 mm and a width of 10 mm. The slightly different shaped crack inducers were installed for inducing cracks at both ends of ARCP. The crack inducers were primarily made of glass fiber reinforced plastic (GFRP) but a crack was induced using a polyethylene sheet inducer. The installed depths of the crack inducers were 30, 40 and 70 mm to the top of the crack inducer from the pavement surface. Most crack inducers were preinstalled on the transverse steel bar locations before concrete pouring, but 2 crack inducers were installed just after concrete placement when concrete was still fresh. The temperature measurement sensors of i-Buttons and thermocouples were installed at the top, middle and bottom of slab to measure the temperature variations of slab. The displacement transducers were also installed at the crack locations to measure the crack width movements. The experimental results showed that the cracks were induced at all the locations where the crack inducers were placed. In addition to the induced cracks, just one crack was formed naturally. The crack patterns on the surface of pavement were all comparable. The crack width measurement data showed that there were slight differences in the crack width movements among the cracks but all the cracks including both the induced and naturally formed cracks moved little within a 0.1 mm range. Therefore, any type of the crack inducers employed in this study can be used to initiate cracks in ARCP.
        83.
        2018.04 구독 인증기관·개인회원 무료
        Haemaphysalis longicornis (Acari: Ixodidae) is a medically important arthropod vector of tick-borne diseases, especially the severe fever with thrombocytopenia syndrome (SFTS). To establish a management strategy against tick-borne diseases, it is fundamental to understand the basic biology of vector species. Therefore under laboratory conditions, we evaluated the horizontal movement of adult and nymph stages of H. longicornis to better understand their dispersal behaviors. In the experiments, field populations were subjected to video recording of the horizontal movement of the ticks in a petri-dish arena for 3 hours. Our results indicate that nymphs showed a significantly higher mobility than adults, whereas there was no significant difference in angular velocity. Nymphs moved 3.74 ± 0.26 m at an angular velocity (AV) of 1.60 ± 0.07 deg/s. and adults moved 2.91 ± 0.26 m at an AV of 1.61 ± 0.14 deg/s.
        84.
        2018.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The objective of this study was to investigate the effects of freeze dried placenta supplementation on reproductive performance, colostrum and plasma biochemical composition in pregnant sows. Eleven Landrace × Large white sows were fed with corn-soybean meal diets supplemented with or without 1% freeze dried placenta powder from 10 days before their expected farrowing dates until 10 days postpartum. The colostrum protein content was significantly higher(P=0.043) in the treatment group than in the control group. Compared to the control group, the immunoglobulin G(IgG) concentration in the colostrum was significantly higher(P=0.004) in the treatment. In day 25 piglets plasma, the IgG concentration was higher(P=0.184) in the treatment than the control. The mortality rate was lower(P=0.102), and the piglet weight gain was higher(P=0.35) in the treated group. Overall, the treatment group showed greater levels of protein and IgG concentration in the colostrum, when compared to control group. Therefore, the freeze dried placenta supplementation on pregnant sows can enhance its colostrum composition, hence decrease the mortality and increase the growth rate of piglets.
        4,000원
        85.
        2017.12 KCI 등재후보 구독 인증기관 무료, 개인회원 유료
        Breast cancer is of enormous concern worldwide and linked with age, sex, hormonal factors, and family history. The treatment of early breast cancer includes treating the disease locally with surgery, radiation therapy, or both and treating microscopic systemic disease with either one or a combination of chemotherapy, endocrine therapy, or biologic therapy. Doxorubicin is a well-known anthracycline antibiotic and antineoplastic drug usually administered to breast cancer patients. However, there have been some reports suggesting that doxorubicin causes side effects such as cardiotoxicity. Furthermore, breast cancer patients on doxorubicin treatment are commonly prescribed steroid suppression therapy. In addition, it has been previously reported that lack of estrogen elevates cardiotoxicity. In this study, we evaluated whether the steroid suppression therapy might influence the cardiotoxicity of doxorubicin. We hypothesized that the presence of a steroid hormone, particularly estrogen, is closely related to doxorubicin action. To investigate the effect of estrogen, mice were divided into four groups: control group, doxorubicin-treated group, ovariectomized group, and ovariectomized plus doxorubicin-treated group. We observed upregulation of inflammatory cytokine gene and downregulation of apoptotic genes in the groups treated with doxorubicin, particularly in the ovariectomized plus doxorubicin-treated group. This suggests that administration of doxorubicin under a non-steroid condition can excessively damage the heart. In summary, combination treatment of hormonal and doxorubicin therapy for breast or many different types of cancer patients must be prescribed with requisite precautions.
        4,000원
        94.
        2016.10 구독 인증기관·개인회원 무료
        Bombolitin is a venom peptide originally isolated from bumblebees and possesses various biological activities, including hemolytic activity. Bombolitins exhibit amphipathic α-helical structure in lipid-membrane-mimicking environments. To investigate their pharmacological and toxicological properties, anti-tumor, anti-microbial and cytotoxic activities of bombolitins from Bombus ardens and Bombus ussurensis were evaluated. Bombolitins of the two species exhibited extremely high anti-tumor activity against ovarian tumor cells SK-OV-3 and NIH; OVCAR-3 at 25-50 μM, which is 2-fold more potent than other wasp venom peptides studied to date (Yoon et al., 2015; Yoon et al., 2016). The two bombolitins showed significantly high antimicrobial activity. However, bombolotin of B. ussurensis showed no antimicrobial activity against Escherichia coli. In addition to their high levels of anti-tumor activity, bombolitins showed considerable levels of hemolytic activity. Thus, to utilize bombolitins as a potential candidate for anti-tumor peptide drugs, further studies for reducing cytotoxic properties of bombolitns is essential.
        95.
        2016.10 구독 인증기관·개인회원 무료
        The habitat of the cockroach varies by species. The German cockroach (Blattella germanica) lives in human dwellings, while the Japanese field roach (Blattella nipponica) lives in a mountainous region. Based on phylogenetic analysis of mtCO I, the two species are closely related to each other and B. germanica is divergent from wild species such as B. nipponica. Their habitats and walking speed differ even though the two species have similar morphology. We hypothesized that habitats might influence walking speed via changes to appendage morphology and enzyme-based physiological differences. We found that phenotype such as appendage length and esterase isozyme expression were clearly different between the two species. These differences might be responsible for the observed difference in walking speed.
        96.
        2016.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Arsenic (As) is a toxic element that easily taken up by plants root. Several toxic forms of As disrupt plant metabolism by a series of cellular alterations. In this study, we applied annealing control primer (ACP)-based reverse transcriptase PCR (polymerase chain reaction) technique to identify differentially expressed genes (DEGs) in alfalfa roots in response to As stress. Two-week-old alfalfa seedlings were exposed to As treatment for 6 hours. DEGs were screened from As treated samples using the ACP-based technique. A total of six DEGs including heat shock protein, HSP 23, plastocyanin-like domain protein162, thioredoxin H-type 1 protein, protein MKS1, and NAD(P)H dehydrogenase B2 were identified in alfalfa roots under As stress. These genes have putative functions in abiotic stress homeostasis, antioxidant activity, and plant defense. These identified genes would be useful to increase As tolerance in alfalfa plants.
        4,000원
        97.
        2016.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구에서는 해상용 경유의 희석량에 따른 선박용 윤활유의 점도 및 전단응력의 변화 등 유변학적 거동에 대한 연구를 하였다. 연료희석에 의한 윤활유의 점도감소는 피스톤링 및 라이너의 마모로 인한 엔진내구성을 저하키는 중요한 요소이다. 연구에 사용된 윤활유는 고유황 경유(황함유량 0.05 %)를 3 %, 6 %, 10 %, 15 %, 20 %로 희석하여 magnetic stirrer를 이용, 혼합하여 제조하였다. 측정온도는 -10℃ ~ 80℃ 범위로 설정하고, 점도 및 전단응력 변화는 회전점도계인 Brookfield Viscometer를 이용하여 측정하였다. 윤활유에 해상용 경유의 희석량이 증가할수록 점도 및 전단응력이 감소하며, 이것은 상대적으로 낮은 점도의 해상용 경유가 윤활유에 희석됨에 따라 윤활유의 점도 및 전단응력이 낮아지기 때문이다. 특히, 저온(0 ~ -10℃)에서는 점도 및 전단응력이 급격이 낮아지다가, 40℃ 이상에서는 점도 및 전단응력 감소가 해상용 경유 희석량의 영향을 거의 받지 않는다. 온도가 높아짐에 따라, 윤활유의 점도 및 전단응력 감소는 윤활유의 뉴턴유체 거동을 보이는 것을 확인했다. 경유의 혼입에 의한 점도감소로 선박의 엔진마모를 촉진할 수 있으므로 엔진의 내구성 향상을 위해 윤활유의 주기적인 관리가 필요하다.
        4,000원
        98.
        2016.04 구독 인증기관·개인회원 무료
        The lesser paper wasp, Parapolybia varia, belongs to large subfamily Polistinae and is distributed in Middle East, the Indo-Papuan region and East Asia. P. varia is known to become aggressive when disturbed for defending their colonies, resulting in fatal envenomation. Vespid chemotactic peptide (VCP) and vespakinin have recently been determined to be the top two genes most abundantly transcribed in venom glands of P. varia. To investigate the pharmacological and toxicological properties of VCP and vespakinin, their antitumor, antimicrobial, and cytotoxic activities were evaluated. VCP exhibited a significantly high antitumor activity against ovarian tumor cell SK-OV-3 at 100 M. VCP also showed higher hemolytic activity than vespakinin. Antimicrobial activity was only observed with VCP against yeast Candida albicans at 1 mM. Since VCP showed a relatively low hemolytic activity but a considerable level of antitumor activity, it has further merits to be exploited as a potential antitumor agent with reduced side effects on normal cells.
        99.
        2015.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        경기도 8개 지역에서 2010년부터 2012년 동안 식균성인 노랑무당벌레의 발생기주를 조사한 결과, 흰가루병에 감염된 12종의 식물에서 관찰 이 되었다. 특히 가장 밀도가 높았던 배과원에서 노랑무당벌레는 7월 상순부터 11월 상순까지 발견되었다. 식균성인 노랑무당벌레의 장내에서는 흰가루병 균사나 포자 외에 다른 먹이의 흔적이 발견되지 않았고, 알과 번데기를 제외한 전 발육단계에서 균을 섭식하는 특성을 볼 때 절대적 식균성 곤충으로 생각된다. 25℃에서 오이 흰가루병균을 섭식한 노랑무당벌레의 발육기간은 알, 유충, 번데기, 성충이 각각 3.9, 10.4, 4.1, 37.7일 이었고, 발육단계별 오이 흰가루병 섭식량은 45.6, 144.4, 372.2, 628.1, 473.7 mm 2로 4령, 성충, 3령, 2령, 1령 순으로 많았다. 본 연구를 통해 노랑무당벌 레의 오이 흰가루병에 대한 섭식능력을 바탕으로 향후 유용 토착천적으로써 대량사육기술, 저독성 약제 선발 등 작물 흰가루병 종합방제기술(IPM) 에 대한 연구가 필요하리라 사료된다.
        4,000원
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