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        검색결과 43

        22.
        2016.10 구독 인증기관·개인회원 무료
        The environmental friendly control of Platypus koryoensis (Murayama), a vector of oak wilt disease, was investigated using citral. To develop an effective attracted trap was performed in Yeoju (semi-field), Gunpo (field) and Cheongju (field). Using a ratio of four attractant (ethanol 100%, ethanol+citral (90:10, 95:5), ethanol+citral+hexane extract of Quercus mongolica (90:5:5)) was investigated attractive effects for the Platypus koryoensis. Most P. koryoensis were attracted to mixture of ethanol+citral (95:5). As a result, when using a citral in a certain concentration is would be able to develop an effective and environmental friendly control agent.
        23.
        2016.10 구독 인증기관·개인회원 무료
        Monochamus saltuarius is one of the insect vector of pine wilt disease with Monochamus alternatus. The present study aimed to investigate the dose to induce sterile and the effect of sterility according to the gender of M. saltuarius. As the electron beam irradiation dose increased, the hatchability, adult eclosion rate and longevity of the former mid and late maturation feeding stage of adults was slightly reduced. However, there was no difference between these two adults. In addition, female adults were more sensitive to the electron beam than the male adults. Hatchability of the F1 generation of ♂T × ♀N o r♀T × ♂N (T: 200 Gy electron beam irradiation, N: 0 Gy) was completely suppressed. As electron beam irradiation dose increased, the fecundity of female adults were slightly decreased. Results by comet assay showed that electron beam irradiation induced as dose increased DNA damage in M. saltuarius adults. These results suggest that SIT using electron beam may be useful for control of M. saltuarius.
        24.
        2015.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Activated carbons (ACs) were prepared by activation of coal tar pitch (CTP) in the range of 700°C-1000°C for 1-4 h using potassium hydroxide (KOH) powder as the activation agent. The optimal activation conditions were determined to be a CTP/KOH ratio of 1:4, activation temperature of 900°C, and activation time of 3 h. The obtained ACs showed increased pore size distribution in the range of 1 to 2 nm and the highest specific capacitance of 122 F/g in a two-electrode system with an organic electrolyte, as measured by a charge-discharge method in the voltage range of 0-2.7 V. In order to improve the performance of the electric double-layer capacitor electrode, various mixtures of CTP and petroleum pitch (PP) were activated at the optimal activation conditions previously determined for CTP. Although the specific capacitance of AC electrodes prepared from CTP only and the mixtures of CTP and PP was not significantly different at a current density of 1 A/g, the AC electrodes from CTP and PP mixtures showed outstanding specific capacitance at higher current rates. In particular, CTP-PP61 (6:1 mixture) had the highest specific capacitance of 132 F/g, and the specific capacitance remained above 90% at a high current density of 3 A/g. It was found that the high specific capacitance could be attributed to the increased micro-pore volume of ACs with pore sizes from 1 to 2 nm, and the high power density could be attributed to the increased meso-pore volume.
        4,000원
        26.
        2012.09 구독 인증기관 무료, 개인회원 유료
        The previous studies of p16INK4a, pRb, p53, and Ki-67 expression suggested that these markers may be preferentially expressed in cervical neoplasms. The purpose of this study was to assess the expression and the clinical significance of p16INK4a, pRb, p53, and Ki-67 proteins in cervical lesions. We obtained 106 cases with various categories of cervical squamous mucosa, including squamous cell carcinoma (n=35), cervical intraepithelial neoplasia (CIN) II/III (n=26), CIN I (n=10), squamous metaplasia (n=15), and normal squamous mucosa (n=20). Immunohistochemical staining was performed for p16INK4a, pRb, p53, and Ki-67 proteins in formalin-fixed and paraffin-embedded tissue sections of the uterine cervix. Evaluation of immunohistochemical staining was based on the frequencies of expression and the mean immunoreactivity scores (IS) in each diagnostic category. p16INK4a positive sotaining was observed in 26 of 35 cases (74.3%) of squamous cell carcinoma, in 16 of 26 cases (61.5%) of CIN II/III, in six of 10 cases (60%) of CIN I, in nine of 15 cases (60%) of squamous metaplasia, and negative in normal squamous mucosa. pRb expression was detected in all diagnostic categories; however, the proportion of pRb positive cells was relatively decreased in CIN II/III (38.5%) and squamous cell carcinomas (51.4%), compared to normal squamous epithelium (90%) and squamous metaplasia (73.3%). No significant differences in expression of p53 were observed in any diagnostic categories. Ki-67 expression was increased in squamous cell carcinoma (37.1%), CIN II/ III (42.3%), and CIN I (40%), but negative in squamous metaplasia and normal mucosa. In 35 cases of squamous cell carcinomas, multivariate analysis revealed no differences in pINK4a, pRb, p53, and Ki-67 expression according to the age of the patient, lymph node metastasis and clinical stage. In conclusion, the combined use of p16INK4a and Ki-67 immunoreactivity could improve the diagnostic specificity of squamous cell carcinoma of the uterine cervix.
        4,000원
        27.
        2011.03 구독 인증기관 무료, 개인회원 유료
        Ursolic acid is a triterpenoid compound present in many plants. This study examined the antimicrobial activity of ursolic acid against mutans streptococci (MS) isolated from the Korean population. The antimicrobial activity was evaluated by the minimum inhibitory concentration (MIC) and time kill curves of MS. The cytotoxicity of ursolic acid against KB cells was tested using an MTT assay. The MIC90 values of ursolic acid for Streptococcus mutans and Streptococcus sobrinus isolated from the Korean population were 2 μg/ml and 4 μg/ml, respectively. Ursolic acid had a bactericidal effect on S. mutans ATCC 25175 T and S. sobrinus ATCC 33478 T at > 2 × MIC (4 μg/ml) and 4 × MIC (8 μg/ml), respectively. Ursolic acid had no cytotoxic effect on KB cells at concentrations at which it exerted antimicrobial effects. The results suggest that ursolic acid can be used in the development of oral hygiene products for the prevention of dental caries.
        4,000원
        28.
        2010.05 구독 인증기관·개인회원 무료
        The perilla leaf pyralid moth, Pyrausta panopealis Walker (Lepidoptera: Pyralidae), is a serious pest damaging to leaf perilla. In order to establish the life parameters of P. panopealis for eventual purpose of control, the developmental span of each stage were investigated under five temperature regimes (20℃ ~ 3 0℃). In addition, the larvicial efficacy of several on-the-market environment-friendly agricultural materials (EFAMs) was tested. The width of head capsule at each larval stage measured to be the mean of 0.21, 0.32, 0.47, 0.64, and 0.98 mm, respectively. The larval period of P. panopealis was longest at 20ºC as 27.0 days and shortened as temperature goes up to 30ºC as 11.3 days. Survivorship of the larval P. panopealis was the highest at 30ºC as 80%, whereas that of other temperatures ranged from 40% (20ºC) to 62.5% (27.5ºC), indicating that the P. panopealis appears to favor higher temperature. In addition to larval period, the duration of egg, prepupa, and pupa stages also shortened as temperature goes up, whereas the duration of adult stage increased as temperature goes up: from 4.1 days at 20 ºC to 6.1 days at 30ºC. After the perilla leaf pyralid moths were successfully stabilized in indoor environment the larvicidal efficacy of the ten EFAMs that were previously selected from the result of other moth species was tested aimed at 4th instar larvae for 48 hrs. Seven of the ten tested showed more than 90% of mortality within 12 hrs and reached nearly up to 100% within 24 hrs, but the remaining three showed less than ~70%.
        29.
        2009.08 구독 인증기관·개인회원 무료
        The main nutritional problem of sorghum×sudangrass (sudangrass) silage is low quality and dry matter (DM) contents. This experiment was conducted to evaluate whether agricultural byproducts addition of sorghum×sudangrass silage increases DM content and forage quality of the silage. Sorghum×sudangrass silage with added byproducts had low pH values, however sorghum×sudangrass silage (control) had a high pH value because of its high moisture content. Silage added with byproduct had lower acid detergent fiber (ADF) and neutral detergent fiber (NDF) contents than control silages, while its non-fiber carbohydrate (NFC), and total digestible nutrients (TDN) and lactic acid contents showed the opposite results. Silages added with crushed rice and green grain of rice were higher in lactic acid content than othor treatments as well as high DM, NFC, and TDN contents. Silage added with crushed rice and green grain of rice can be recommended as the most effective treatment for increasing forage quality and DM content of sorghum×sudangrass silage.
        30.
        2004.12 구독 인증기관 무료, 개인회원 유료
        Human embryonic stem (ES) cells are derived from the inner cell mass of the preimplantation embryo. Human ES cells have the capacity to differentiate into various types of cells in the body. Human ES cells are indefinite source of cells for cell therapy in various degenerative disorders including neuronal disorders. Directed differentiation of human ES cells is a prerequisite for their clinical application. The objective of this study is to develop the culture condition for the derivation of neural precursor cells from human ES cells. Neural precursor cells were derived from human ES cells in a stepwise culture condition. Neural precursor cells in the form of neural rosette structures developed into neurospheres when cultured in suspension. Suspension culture of neurospheres has been maintained over 4 months. Expressions of nestin, soxl, sox2, pax3 and pax6 transcripts were upregulated during differentiation into neural precursor cells by RT-PCR analysis. In contrast, expression of oct4 was dramatically downregulated in neural precursor cells. Immunocytochemical analyses of neural precursor cells demonstrated expression of nestin and SOX1. When induced to differentiate on an adhesive substrate, neuro-spheres were able to differentiate into three lineages of neural systems, including neurons, astrocytes and oligo-dendrocytes. Transcripts of sox1 and pax6 were downregulated during differentiation of neural precursor cells into neurons. In contrast, expression of map2ab was elevated in the differentiated cells, relative to those in neural precursor cells. Neurons derived from neural precursor cells expressed NCAM, Tuj1, MAP2ab, NeuN and NF200 in immunocytochemical analyses. Presence of astrocytes was confirmed by expression of GFAP immuno-cytochemically. Oligodendrocytes were also observed by positive immuno-reactivities against oligodendrocyte marker O1. Results of this study demonstrate that a stepwise culture condition is developed for the derivation of neural precursor cells from human ES cells.
        4,000원
        37.
        2016.10 서비스 종료(열람 제한)
        Background : Ginseng, one of most famous traditional oriental medicines, has been known for a number of pharmacological properties including anti-tumor, anti-diabetic, anti-fatigue, anti-stress, anti-oxidative, and anti-aging effects. 20(S)-Protopanaxadiol (PPD), a intestinal metabolite of ginsenosides, is one of the active ingredients in ginseng. In this study, we investigated the synergistic anticancer effect of 20(S)-PPD and temozolomide (TMZ) and the mechanism of 20(S)-PPD on glioblastoma cells. Methods and Results : We examined cell viability and the morphological changes of C6 cells after treatment of 20(S)-PPD and TMZ. 20(S)-PPD showed a potent antiproliferative activity against C6 cells by triggering apoptosis. 20(S)-PPD-induced apoptosis was characterized by a dose-dependent mitochondrial damage. 20(S)-PPD and TMZ had a synergistic effect in increasing mitochondrial damage via caspase 3 activation. Conclusion : These results revealed an unexpected mechanism of 20(S)-PPD and TMZ, triggering a mitochondrial-mediated apoptosis in C6 cells. Our findings encourage further studies of 20(S)-PPD as a promising chemopreventive agent against glioblastoma.
        38.
        2015.12 KCI 등재 서비스 종료(열람 제한)
        피부는 외부 유해물질로부터 내부기관을 보호하는 장벽기능을 하는 대표적인 기관으로 자외선 (ultraviolet radiation, UV), 중금속, 각종 산화 물질들과 같은 외부의 위협에 항상 노출되어 있어 손상을 받 기 쉽다. 특히 자외선 B (UVB)는 진피의 상부까지 도달하여 화상이나 홍반과 같은 염증반응을 일으키며 멜라 닌 생성을 촉진시켜 색소 침착을 유발한다. 지나친 자외선 B의 피부세포로의 유입은 각질세포 및 진피 섬유아 세포의 DNA손상을 야기하고, 세포외기질의 합성을 방해하여 피부탄력감소, 주름생성, 진피 결합조직의 손상 과 함께 피부장벽을 붕괴시켜 노화를 일으키며, 장기간 노출 시 심각한 피부 병변으로 이어져 피부세포 사멸 및 종양의 발생으로까지 이어진다. Haloarcula vallismortis는 사해로부터 분리 동정한 미생물로 호염성 고생 물의 생장적 특징은 아직 자세히 연구된 바는 없다. 대게 10% 이상의 염도에서 자라는데 실제 생장염도는 평균 20 ∼ 25% 염도에서 자란다. 염도가 높은 호수나 염전에서 주로 발견되기 때문에 강한 햇빛에 대한 방 어기작이 존재한다. 그중 하나로 다른 ATP를 생성하기 위한 bacteriorhodopsin외에 halorhodopsin이라는 색소를 이용, 광자(photon)를 흡수하고 염화이온 채널을 개방시켜 생기는 전위차를 이용해 추가로 에너지를 생산한다. 또 carotenoid 색소로 인해 농도가 높을시 분홍색 또는 빨간색을 띄는 특징이 있는데 이것이 강한 자외선에 대한 방어기작을 할 것이라고 여겨진다. 본 연구는 호염성 고세균이 자외선을 에너지 소스로 이용하 는 특성을 이용하여 자외선으로부터 피부를 방어하는 방법을 개발하고자 이들의 피부각질세포에서 자외선에 의한 항염 효과 및 DNA 손상 방어 효과를 확인하였다. 그리고 이들을 천연 자외선 차단제의 소재로서 사용 할 수 있음을 확인하였다.
        40.
        2011.09 서비스 종료(열람 제한)
        Mesenchymal stem cells (MSC) are of great interest for cell-based therapies and tissue engineering approaches, as these cells are capable for extensive self-renewal and display a multilineage differentiation potential. Clinical application of these cells for degenerative and age-related diseases has been accumulating. However, preparation of MSC before the onset of the diseases, it needs to develop the cryopreservation method. Most cryopreservation methods include fetal bovine serum (FBS) which is essential for effective cryopreservation. Yet it should not be used clinically because of the potential risk of infection. In the present study, we investigated whether human serum albumin (HSA), human serum (HS), and knockout serum replacement (KSR) can be used as an alternative of FBS for cryopreservation of human adipose derived stem cells (hADSC). Cells cryopreserved with 9% HSA showed much higher viability after thawing compared with cells frozen with 5% or 1% HSA. Cells cryopreserved with 90% HS or KSR exhibited greater viability than cells frozen with 25% and 5% HS or KSR, respectively. Viability of cells frozen with 9% HSA, 90% HS or 90% KSR was comparable to that with 90% FBS. Morphology and proliferation ability of these cells were not affected by cryopreservation when compared the freshly obtained cells. Cryopreserved hADSC expressed transcription factor genes including Oct3/4, Nanog, Nestin and Sox2, which are related to the self-renewal of stem cells. Flow cytometric analyses showed that both fresh and cryopreserved hADSC were positive for the antigens of HLA-ABC, CD44, CD73, CD90, and CD105, CD166, and negative for HLA-DR, CD31, and CD34. Similar to fresh cells, cryopreserved hADSC could differentiate into mesodermal lineages, adipogenic, osteogenic, or chondrogenic cells. These results suggest that 9% HSA, 90% HS or 90% KSR can be used to replace FBS during successful cryopreservation of hADSC.
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