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        검색결과 1,343

        521.
        2010.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The bactericidal efficacy of three common sanitizers (100 or 200 ppm of sodium hypochlorite, 100or 200 ppm of n-alkyl(C12-C18)benzyldimethyl chloride, and 50 or 100 ppm of peroxyacetic acid) against Escherichia coli ATCC 10536 and Staphylococcus aureus ATCC 6538 was studied using the suspension test method at various exposure temperatures (4~40℃) and times(1~60min) under both dirty and clean conditions, respectively. During the suspension tests, sodium hypochlorite (200 ppm) showed higher bactericidal activity than the other sanitizers under clean conditions, with 5 log reductions against E. coli as well as S. aureus in the first 1 min of treatments at 4℃. However,the efficacy of sodium hypochlorite decreased markedly under dirty conditions due to its susceptibility to interfering substances. The efficacy of the n-alkyl(C12-C18)benzyldimethyl chloride increased considerable as the exposure temperature and time increased. The bactericidal efficacy of the n-alkyl(C12-C18)benzyldimethyl chloride might be less effective on low temperature, however, the longer time the sanitizer is in contact, the more effective the sanitization effect. Treatment with peroxyacetic acid (100 ppm) showed at least 5 log reduction against E. coli and S. aureus for 5min at 4℃ under both clean and dirty conditions. The efficacy of the peroxyacetic acid was not much altered by interfering substances and affected by changes in temperature or time.
        4,000원
        522.
        2010.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Selenium (Se) obtained from dietary sources is an essential micronutrient for normal body function and it functions as an essential constituent of selenoproteins. We investigated the influence of Se on the formation of colonic aberrant crpyt foci (ACF) and tumor formation induced by azoxymethane (AOM) and dextran sodium sulfate (DSS) in male ICR mice. Five-week old ICR mice were acclimated for one week and fed on the low iron diet (LFe, 4.5 ppm) and different Se diet [Lse (0.02 ppm), Normal Se (0.1 ppm), HSe (0.5 ppm)] for 12 weeks. Animals received intraperitoneal injections of AOM (10㎎/㎏ B.W. in saline weekly for 3 weeks), followed by 2% DSS (molecular weight 36,000~50,000) in the drinking water for a week. There were five experimental groups, including a normal control group, AOM/DSS, LFe+AOM/DSS, LFe+AOM/DSS+LSe, LFe+AOM/DSS+HSe. After sacrifice of animals, the total numbers of AC and ACF were measured in the colonic mucosa. The number of mice bearing tumors was expressed as tumor incidence rate. The iron and selenium liver concentration was measured using ICP-AES. Glutathione peroxidase (GPx) activity was determined using a GPx assay kit in the liver and colon. TUNEL and proliferating cell nuclear antigen (PCNA) staining were performed to examine the cell apoptosis and cell proliferation. In addition, immunohistochemistry of β-catenin was also performed on the mucous membrane tissue of colon. In AOM/DSS-induced colon carcinogenesis animal model, LFe diet decreased the number of 2.95±2.5 ACF/cm2 to 1.85±1.1 ACF/cm2 but it increased the total number of 5.06±4.2 AC/cm2 to 6.19±4.8 AC/cm2 compared with normal iron diet. In the iron-deficient mice, selenium did not affect the either the number of ACF or AC. The tumor incidence rate was higher in LFe diet groups than in normal iron diet group and high selenium diet weakly reduced the tumor incidence. Low selenium diet decreased the activity of GPx in the liver and colon. Apoptotic positive cells were decreased in the low selenium diet group. In addition, on the β-catenin staining, positive cells were increased in the low selenium diet group while they were decreased in the high selenium diet group. These findings indicate that the dietary levels of selenium was not highly enough to exhibit a significant protection against colon carcinogenesis in the iron-deficient mice. However, our results also indicate that dietary selenium might exert a protecting effect against colon cancer by increasing GPx activity and apoptosis and by inhibiting cell proliferation and β-catenin over-expression.
        4,500원
        523.
        2010.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        옥수수는 우리나라에서 매우 중요한 사료작물이다. 대부분 사일리지 형태로 이용이 되고 있으며 많은 비율의 곡실을 함유하고 있어 반추가축의 우수한 사료로 이용된다. 본 시험은 옥수수 사일리지용 미생물 첨가제 개발을 위해 수집된 균주의 발효능력을 평가하기 위해 수행되었다. 양질의 옥수수 사일리지에서 선발한 젖산균을 0.02%의 Sodium azide가 들어있는 MRS 배지에 접종을 한 후 균을 분리하여 MRS broth에 접종하여 산 생성 능력을 조사하였다.
        4,000원
        524.
        2010.10 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        Changes in surface morphology and roughness of dc sputtered ZnO:Al/Ag back reflectors by varying the deposition temperature and their influence on the performance of flexible silicon thin film solar cells were systematically investigated. By increasing the deposition temperature from 25˚C to 500˚C, the grain size of Ag thin films increased from 100 nm to 1000 nm and the grain size distribution became irregular, which resulted in an increment of surface roughness from 6.6 nm to 46.6 nm. Even after the 100 nm thick ZnO:Al film deposition, the surface morphology and roughness of the ZnO:Al/Ag double structured back reflectors were the same as those of the Ag layers, meaning that the ZnO:Al films were deposited conformally on the Ag films without unnecessary changes in the surfacefeatures. The diffused reflectance of the back reflectors improved significantly with the increasing grain size and surface roughness of the Ag films, and in particular, an enhanced diffused reflectance in the long wavelength over 800 nm was observed in the Ag back reflectors deposited at 500˚C, which had an irregular grain size distribution of 200-1000 nm and large surface roughness. The improved light scattering properties on the rough ZnO:Al/Ag back reflector surfaces led to an increase of light trapping in the solar cells, and this resulted in a noticeable improvement in the Jsc values from 9.94 mA/cm2 for the flat Ag back reflector at 25˚C to 13.36 mA/cm2 for the rough one at 500˚C. A conversion efficiency of 7.60% (Voc = 0.93, Jsc = 13.36 mA/cm2, FF = 61%) was achieved in the flexible silicon thin film solar cells at this moment.
        4,000원
        529.
        2010.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        1961년부터 2010년 현재까지 현행 국가정선해양관측이 고전적 방법에 의해 수행됨으로써 자동화된 시스템의 형태로 실시간 혹은 준실시간으로 자료를 제공하지 못하게 되는 부분에 대한 개선방향을 살펴보고, 우리나라 운용해양시스템의 실용화를 위하여 국가정선해양관측이 나아가야 할 방향을 제시하였다. 선상에서 관측이 끝난 이후부터 데이터베이스에 자료가 저장되는 시점까지 행해지는 수동화된 작업을 대체하기 위해서는, 수온, 염분뿐만 아니라 다양한 자동측정센서가 부착된 CTD(Conductivity-Temperature-Depth)에 연동된 컴퓨터에서 해양관측자료를 처리하고 실시간으로 품질관리를 수행하며 통신수단에 맞게 자료를 전송할 수 있도록 하는 자동화 소프트웨어의 개발이 필요하다. 관측자료를 실시간의 형태로 전송하기 위해서는 Inmarsat 위성통신장비를 활용한 전송시스템이 타당하고, 준실시간 형태의 전송으로는 CDMA(Code Division Multiple Access) 무선통신방식을 사용하여 연안역에 도달했을 때 수집된 자료들을 묶어서 보내는 방식이 적합하다. 실시간 품질관리 과정을 포함시켜 관측시 발생할 수 있는 여러 가지 원인의 오류를 미연에 방지할 수 있을 것이다.
        4,000원
        530.
        2010.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Porcine circovirus type 2 (PCV2) is associated with porcine circovirus diseases (PCVD), of which postweaning multisystemic wasting syndrome is considered to cause considerable economic losses in pig industry worldwide. As the virus-like particle (VLP) is a highly effective type of subunit vaccine and has unique advantages in terms of safety and immunogenicity, this study aimed to develop PCV2-like particles, which matched currently circulating Korean PCV2 and were applicable as vaccines. The ORF2 genes encoding PCV2 capsid protein were amplified from the PCV2 subgroup 1A/B Korean C275 isolate and the subgroup 2E C94 isolate by PCR assay with primer pair specific to PCV2 ORF2 gene, and were cloned into baculovirus transfer vector. Recombinant baculovirus was generated by cotransfection with the transfer vector and linear baculovirus DNA into the Sf9 cells, and then by plaque purification. Expression of PCV2 capsid protein was determined by the indirect immunofluorescence and Western blotting assays, and electron microscopy. By both immunological assays, PCV2 capsid antigen was detected in the Sf9 cells infected with the recombinant baculoviruses. The formation of empty virus particles, characteristic of VLP, was detected in the lysate of Sf9 cells infected with the recombinant baculoviruses by negative electron microscopy. From these results, VLPs of two genogroups of PCV2 were successfully expressed and generated in a baculovirus expression system. It is expected that the expressed VLPs of two genotypic groups can be used for control of PCV2 infection as good vaccine candidates.
        4,000원
        531.
        2010.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 시험은 신품종 톨 페스큐를 육성하기 위하여 1999년부터 2007년까지 국립축산과학원 초지사료과에서 수행되었다. 톨 페스큐 신품종 '그린마스터'는 6배체 품종으로서 엽은 녹색이며, 출수기가 5월 14일경이며 풍엽성이 우수한 품종이었다. 4개 지역평균 건물수량은 '그린마스터' 19,156 kg/ha로서 대비품종인 'Fawn' 보다 11% 많았으며, 지역별로는 4개 지역 모두에서 'Fawn' 보다 생산성이 우수하였다. '그린마스터'의 사료가치는 조단백질
        4,000원
        534.
        2010.09 구독 인증기관 무료, 개인회원 유료
        Early diagnoses of pregnancy for animal such as swine and bovine is extremely important to increase income of a farmhouse and for the management of farm. For the development of immunoasaay system of pregnancy in swine, we report a competitive heterologous enzyme linked immunosorbent assay (ELISA) for the direct measurement of oestrone sulfate (E1S) in diluted urine using anti-E1G (glucuronide) monoclonal antibody which cross react with E1S. The principle of assay was based on the typical solid-phase competitive ELISA methods using E1G-HRP (horseradish peroxidase) as a tracer and E1S for standard. The method had a reasonable sensitivity for the detection of E1S with 0.15 ng/ml as a detection limit. The intra-assay and inter-assay precisions were raging coefficient of from 8.50~9.67% and 8.50~9.87%, respectively, which were quite acceptable. In a field trial with a group 37 sows (18 non-pregnancy and 19 pregnancy sows) after day 29~30 post service, the concentration of E1S were determined to be below 30 ng/ml in all non-pregnancy group and over 48 ng/ml in pregnancy group except one sample. The method described here, heterologous ELISA for the measurement of E1S in urine is good enough for monitoring the early pregnancy test of swine.
        4,000원
        535.
        2010.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The objective of this study was to determine physiological and mechanical factors effecting on the pregnancy rates following artificial insemination in dairy cattle. Estrus for artificial insemination of cows was checked whether the outflow of mucus from the elements was out flow or not. There were no significant difference of gestation rates with mucus release (31.76%) and without mucus release (24.03%). The pregnancy rates were 39.02% in 10~20mm of follicle size group and 27.08% (p<0.05) in 20~30mm diameter of the follicles. There were not different pregnancy rates between twice inseminated dairy cattle and more than 3 times inseminated cattle. The pregnancy rate was 28.57% under automatic milking system. In contrast, under artificial milking system pregnancy rate was 56.85%. Two systems significantly (p<0.05) were different. These results suggest that pregnancy rates were not effected by physiological system, but mechanical condition.
        4,000원
        537.
        2010.09 구독 인증기관 무료, 개인회원 유료
        This study was to investigate the effect of flavonoid treatment on in vitro development of bovine somatic cell nuclear transfer (SCNT) embryos, and their pregnancy and delivery rate after embryo transfer into recipient. In experiment 1, to optimize the flavonoid concentration, parthenogenetic day 2 (≥ 2-cell) embryos were cultured in 0 (control), 1, 10 and 20 μM flavonoid for 6 days. In the results, in vitro development rate was the highest in 10 μM flavonoid group (57.1%) among treatment groups (control, 49.5%; 1 μM, 54.2%; 20 μM, 37.5%), and numbers of total and ICM cells were significantly (p<0.05) higher in 10 μM flavonoid group than other groups. We found that 10 μM flavonoid treatment can significantly (p<0.05) decrease the apoptotic index and derive high expression of anti-oxidant, anti-apoptotic, cell growth and development marker genes such as Mn-SOD, Survivin, Bax inhibitor, Glut-5, In-tau, compared to control group. In experiment 2, to produce the cloned Jeju Black Cattle, beef quality index grade 1 bull somatic cells were transferred into enucleated bovine MII oocytes and reconstructed embryos were cultured in 10 μM flavonoid added medium. When the in vitro produced day 7 or 8 SCNT blastocysts were transferred into a number of recipients, 10 μM flavonoid treatment group presented higher pregnancy rate (10.2%, 6/59) than control group (5.9%, 2/34). Total three cloned Jeju Black calves were born. Also, two cloned calves in 10 μM flavonoid group were born and both were all healthy at present, while the one cloned calf born in control group was dead one month after birth. In addition, when the result of short tandem repeat marker analysis of each cloned calf was investigated, microsatellite loci of 11 numbers matched genotype between donor cell and cloned calf tissue. These results demonstrated that the flavonoid addition in culture medium may have beneficial effects on in vitro and in vivo developmental capacity of SCNT embryos and pregnancy rate.
        4,000원
        538.
        2010.06 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        Silicon quantum dots (Si QDs) in a superlattice for high efficiency tandem solar cells were fabricated by magnetron rf sputtering and their characteristics were investigated. SiC/Si1-xCx superlattices were deposited by co-sputtering of Si and C targets and annealed at 1000˚C for 20 minutes in a nitrogen atmosphere. The Si QDs in Si-rich layers were verified by transmission electron microscopy (TEM) and X-ray diffraction. The size of the QDs was observed to be 3-6 nm through high resolution TEM. Some crystal Si and -SiC peaks were clearly observed in the grazing incident X-ray diffractogram. Raman spectroscopy in the annealed sample showed a sharp peak at 516 cm-1 which is an indication of Si QDs. Based on the Raman shift the size of the QD was estimated to be 4-6 nm. The volume fraction of Si crystals was calculated to be about 33%. The change of the FT-IR absorption spectrum from a Gaussian shape to a Lorentzian shape also confirmed the phase transition from an amorphous phase before annealing to a crystalline phase after annealing. The optical absorption coefficient also decreased, but the optical band gap increased from 1.5 eV to 2.1 eV after annealing. Therefore, it is expected that the optical energy gap of the QDs can be controlled with growth and annealing conditions.
        4,000원
        539.
        2010.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The purpose of this study was to examine the appearance of norovirus in the water for food in food service institutions and the influence of physicochemical and microbial factors of norovirus in order to work out basic data to predict the detection of norovirus. Among 82 samples of water for food in food service institutions, norovirus appeared in 7 samples and the rate of appearance was 8.5%. As for the type of norovirus, one samples contained GI type (genotype GI-6) and six samples contained GII type (genotype GII-2, GII-4, GII-12). In the regression model of prediction of norovirus, the rate of appearance was correlated with NH₃-N, total solids and the consumption of KMnO₄, out of such variables as NH₃-N, total solids, the consumption of KMnO4, depth, chloride and total colony counts, and its contribution rate for effectiveness was 78.60%. In order to examine the influential factor of environment upon the detection of norovirus, Pearson's correlation analysis was carried out. The predictable regression formula for appearance rate of norovirus was expressed as -1.818 + 42.677 [NH₃-N] + 0.023 [total solids] + 0.762[consumption of KMnO₄] -0.009 [depth] -0.146 [chloride] + 0.007 [total colony counts] (R = 0.904, R² = 0.818,adjusted R² = 0.786, p < 0.05). The most influential factors upon the detection of norovirus were NH₃-N, total solids and the consumption of KMnO₄. In other words, when the measured values of NH₃-N, total solids and the consumption of KMnO₄ were higher, the possibility of appearance of norovirus increased.
        4,000원
        540.
        2010.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Differences in the number of Platypus koryoensis (Murayama) (Coleoptera: Platypodidae) trapped in different trap types, colors and positions on the trunk were evaluated to develop a monitoring trap for Platypus koryoensis, a known vector of Korean oak wilt disease. The experiments were conducted in an oak forest located in Gwangtan-myeon, Paju-si, Gyeonggi-do, Korea using two types of trap: sticky trap and multi-funnel trap. Trapping efficiency of the two trap types was not significantly different. Trapping efficiency of the sticky trap was not affected by four trap colors: yellow, black, white and transparent. The number of beetle caught was higher in the traps facing the upper slope than the lower slope regardress of trap type. Our results showed that both traps type are useful for monitoring Platypus koryoensis.
        4,000원