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        검색결과 417

        201.
        2012.06 구독 인증기관·개인회원 무료
        The objective of this study was to assess the effect on post-thawed sperm motility, viability and acrosome integrity of boar semen frozen in the freezing extender with chicken or duck egg yolks. The Sperm rich fraction of ejaculates from three Duroc boars were collected by a glove-hand technique. Samples with more than 80% motile sperm were used for this experiment. Semen was diluted with freezing extender (LEY) containing 11% (v/v) lactose, 20% (v/v) hen egg yolk with 3.5% (v/v) glycerol, and 0.5% (v/v) Orvus Es Paste(OEP, Nova Chemical Sales Inc., Scituate, MA. USA) to yield a final sperm concentration of 5×108 cells/ml. Following complete dilution, semen samples were loaded in 0.5 ml French medium straws (IMV technologies, France) and transferred to programmable semen freezer (SY-LAB Gerate GmbH, Austria). For freezing the semen samples, each straw was cooled from 5℃ to — 5℃ at 6℃/min, auto-seeding at — 5℃ and held for 60sec, samples were then cooled from — 5 to — 80℃ at 40℃/min, and thereafter from — 80℃ to — 150℃ at 60℃/min. The yolks used were sourced from fresh chicken and duck eggs. To evaluate the post-thaw sperm quality, semen was thawed at 38℃ for 20 sec and sperm motility, viability and acrosome integrity were assessed. Motility was assessed for %motile cell characteristics using computer-assisted semen analysis (CASA; SAIS SI-100, Medical supply, Korea). The percentage of sperm viability was assessed using LIVE/DEAD® sperm viability kit (Molecular probes, Eugene, OR, USA). The acrosome integrity was assessed by FITC-PNA staining. Sperm quality in terms of motility, viability and acrosome integrity showed higher after freezing in medium containing duck yolk than chicken yolk. However, there was no significant difference in sperm quality for the different types of yolk(p>0.05). * The result of this study showed that there was no significant difference between the egg yolk types when considering the sperm motility, viability and acrosome integrity of boar semen frozen in the freezing extender with chicken or duck egg yolks.
        203.
        2012.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The near explosion of attention given to graphene has attracted many to its research field. As new studies and findings about graphene synthesis, properties, electronic quality control, and possible applications simultaneous burgeon in the scientific community, it is quite hard to grasp the breadth of graphene history. At this stage, graphene's many fascinating qualities have been amply reported and its potential for various electronic applications are increasing, pulling in ever more newcomers to the field of graphene. Thus it has become important as a community to have an equal understanding of how this material was discovered, why it is stirring up the scientific community and what sort of progress has been made and for what purposes. Since the first discovery, the hype has expediently led to near accomplishment of industrial-sized production of graphene. This review covers the progress and development of synthesis and transfer techniques with an emphasis on the most recent technique of chemical vapor deposition, and explores the potential applications of graphene that are made possible with the improved synthesis and transfer.
        4,900원
        204.
        2011.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The aim of this study was to evaluate the post-thawed characteristics of leopard cat semen. In this experiment, semen was collected from two leopard cats (A and B) at wild animal center in Seoul Grand Park in Korea. After collection, the sperms were washed with D-PBS and diluted by the freezing medium (Irvine science, USA) and stored in liquid nitrogen. The post-thawed concentration was for A and for B. The viability of post-thawed sperm from A and B individual was 24.0% and 19.0%, respectively. Pre-freezing motility of A and B individual semen was 68.54% and 56.65. Leopard cat A had more normal sperm than that of B (69.5% vs. 54.5%). Acrosome integrity analysis detected live (14.5% vs. 9.0%), damage (39.0% vs. 44.0%) and dead (46.0% vs. 47.0%) in leopard cat A and B, respectively. The present results concluded that leopard cat semen can be collected successfully by electro-ejaculation method and cryopreserved successfullyfor future use in different assisted reproductive technologies. The cryopreservation protocol needs to be modified for increasing post-thawed viability of leopard cat spermatozoa.
        4,000원
        206.
        2011.09 구독 인증기관 무료, 개인회원 유료
        The notion that dental amalgam is a potential source of mercury exposure remains a controversial issue. However, there are few epidemiological analyses that have addressed whether this occurs in children. We aimed in our current study to identify the relationship between dental amalgam filling surfaces and the blood mercury levels in a cohort of 711 South Korean children aged between 8-9 years. Oral examinations were conducted to detect the number of amalgam filling surfaces on the teeth of these individuals. Blood samples were also taken from these children to assess the levels of mercury accumulation in the body. The amalgam filling surfaces were classified into four groups based on their number: 0 (n = 368), 1-5 (n = 219), 6-10 (n = 89), and 11+ (n = 35). The blood mercury levels in the children with more than 10 amalgam surfaces was 0.47 μg/L higher on average than those with no amalgam surfaces after adjusting for the frequency of fish or seafood consumption, age, and gender (P < 0.05). We found from our data that a higher number of dental amalgam fillings correlated with a higher blood mercury level in Korean children. Further studies are needed to investigate whether these elevated mercury levels exert neurotoxic or nephrotoxic effects.
        4,000원
        207.
        2011.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Ovulation synchronization (ovsynch) has proved to increase the number of insemination in cattle by overcoming the problems of heat detection. The aim of this study was to do ovsynch in water buffaloes where heat detection is a major reproductive problem and to determine the conception rates after timed artificial insemination (TAI). Twenty cyclic buffaloes at 60 days postpartum were selected by examining 24 unobserved estrus buffaloes based on milk progesterone assay (progesterone concentration 1.0 ng/ml) from the Mymensingh district of Bangladesh. Ovsynch treatment regimen was started irrespective of the stage of estrous cycle. Gonadorelin (500 ) was injected intramuscularly at Day 0 followed by Alfaprostol (8 mg) at Day 7. A second injection of Gonadorelin was given at Day 9 and TAI was done with frozen semen from Mediterranean buffalo bulls at 16~20 hours of the second Gonadorelin injection. Milk progesterone ELISA at Day 10~12 post AI confirmed ovulation in 16 out of 20 (80%) buffaloes (progesterone concentration 1.0 ng/ml). High progesterone concentration ( 1.0 ng/ml) at Day 10~12 and Day 22~24 of AI showed pregnancy in six out of 20 (30%) buffaloes. Pregnancy was further confirmed by ultrasonography at Day 40 in these six buffaloes. In conclusion, ovsynch followed by TAI could be applied in cyclic buffaloes for overcoming the estrus detection problems; however, more studies are needed to increase the conception rate.
        4,000원
        208.
        2011.06 구독 인증기관 무료, 개인회원 유료
        This study describes the development of a web-based system that collects all data generated in the research conducted to set pre-harvest residue limits (PHRLs) for agricultural product safety control. These data, including concentrations of pesticide residues, limit of detection, limit of quantitation, recoveries, weather charts, and growth rates, are incorporated into a database, a regression analysis of the data is performed using statistical techniques, and the PHRL for an agricultural product is automatically computed. The development and establishment of this system increased the efficiency and improved the reliability of the research in this area by standardizing the data and maintaining its accuracy without temporal or spatial limitations. The system permits automatic computation of the PHRL and a quick review of the goodness of fit of the regression model. By building and analyzing a database, it also allows data accumulated over the last 10 years to be utilized.
        6,600원
        210.
        2011.05 구독 인증기관·개인회원 무료
        The repellency of 104 plant essential oils to female Aedes aegypti was examined using a cage-distribution assay. Results were compared with those of the conventional mosquito repellent N,N-diethyl-m-toluamide (DEET). Coriander, oreganum, pennyroyal, lemoneucalyptus, and spearmint exhibited high repellency effect (>60 minutes at 50 mg/filter paper), followed by sage, leavander, tarragon, bergamot, and neroli oils which showed moderate effective (< 40 minutes at 50 mg/filter paper (5 cm diameter)). In the light of global efforts to reduce the level of highly toxic synthetic repellents, essential oils described merit further study as potential repellents for the control of mosquito populations.
        211.
        2010.05 구독 인증기관·개인회원 무료
        The porcine reproductive and respiratory syndrome virus (PRRSV) has three major structural proteins which designated as GP4, GP5, and M. They have been considered very important to arouse the humoral and cellular immune responses against PRRSV infection and proposed to be the excellent candidate proteins in the design of PRRS bioengineering vaccine. However, the PRRSV structural proteins are produced in low levels in the infected cells because it forms insoluble protein and possesses several transmembrane regions. To overcome this problem, we fused the GP4, GP5, and M with SUMO (Small ubiquitin-related modifier), and expressed the fused gene in Bm5 cells and silkworm larvae. Expression of the proteins were analyzed by 12% SDS-PAGE and western blotting using 6xHis tag and porcine anti-PRRSV antibodies. In results, SUMO fused proteins were expressed at a high level in Bm5 cells. The levels of protein using the silkworm larvae is higher than that using Bm5 cells. The fused protein was purified by Ni-NTA affinity chromatography. This study demonstrated that SUMO, when fused with PRRSV structural proteins, was able to promote its soluble expression. This may be a better method to produce PRRSV structural proteins for vaccine development.
        213.
        2009.10 구독 인증기관·개인회원 무료
        The Classical Swine Fever Virus (CSFV) is a member of the Pestivirus genus of the Flaviviridae. The genome of CSFV is a positive single-stranded RNA molecule 12.3 kb and contains a single large open reading frame (ORF). The polyprotein composed of eight nonstructural and four structural proteins (nucleocapsid protein C and three envelope glycoprotein E0, E1 and E2). E2, the most immunogenic of the CSFV glycoproteins, induces a protective immune response in swine. To determine the characteristics of the CSFV, LOM strain, we investigated the nucleotide sequence of the glycoprotein E0, E1 and E2. Comparison of the LOM with the other strains revealed nucleotide sequence identity ranging from 97 to 98%. Expression of the glycoprotein E2 was identified by SDS-PAGE and Western blot analysis using anti-CSFV E2 monoclonal antibodies in Sf21 cells. The expression levels of glycoprotein E2 were observed from day 3 and 5 days maximum. In addition, its expression efficiency by media and cell line was investigated. The result showed that High-Five cells and Grace’s insect media for Sf21 were the best conditions for the expression of the glycoprotein E2.
        215.
        2009.09 구독 인증기관 무료, 개인회원 유료
        Germinated rough rice (GRR) has many healthy effects such as antioxidant activity, inhibition of chronic inflammatory disease and prevention of vascular disease. In this study, germinated Korean rice sample which was planted in 2008 from Korean Rural Development Administration was used. The purpose of this study was to recognize the effect of the ethanol extract of GRR on the ischemic damage of skeletal muscle. Right femoral artery ligation was performed to induce ischemic condition in mice and the mixed basal diet with the ethanol extract of GRR at various levels (100, 200, and 400 mg/kg diet) was given for 2 weeks. After the mice were sacrificed, the hind limb muscle samples of the mice were fixed, sectioned, stained with Haematoxylin-Eosin (H&E), Masson’s trichrome, and performed for Immunohistochemistry (IHC) for caspase-3. In histopathological findings of H&E and Masson’s trichrome stain, the treatment of GRR at the level of 400 mg/kg diminished fibrosis and necrosis in the muscle compared to the control. The expression of caspase-3 protein was also decreased by the treatment of GRR at the level of 400 mg/kg compared to the control. These results suggest that the ethanol extract of GRR may have a protective effect against muscle damage during the ischemia in skeletal muscle of hindlimb.
        4,000원
        216.
        2009.08 구독 인증기관·개인회원 무료
        This study was carried out to investigate the effects of cattle slurry application in paddy land cultivated with whole crop rice on the properties of soil and water. A field study was conducted at Baeksan-myeon, Kimje, Jeonbuk province in Korea on clay loam soil for 3 years. All plots were arranged in completely randomized design with three replicates. The contents of organic and inorganic properties in soil samples collected at the end of the experiment were remarkably higher than those at the beginning of the experiment (P<0.05). The concentrations of NO₃-N, NH₃-N and PO₄-P in discharge and leaching water were different significantly between both treatments.
        217.
        2009.08 구독 인증기관·개인회원 무료
        This study was carried out to investigate the effects of cattle slurry application on the productivity and nutritive values of whole crop rice in paddy land. A field study was conducted at Baeksan-myeon, Kimje, Jeonbuk province in Korea on clay loam soil for 3 years. All plots were arranged in completely randomized design with three replicates. The yield of dry matter (DM) of whole crop rice in treatment of cattle slurry significantly decreased as compared with that of treatment of standard fertilizer (P<0.05). However, nutritive values of whole crop rice were not different significantly between both treatments.
        218.
        2009.08 구독 인증기관·개인회원 무료
        The experimental work was conducted to investigate the effects of the application level of composted cattle manure (CCM) on forage productivity using Italian ryegrass-WCR double cropping system for 3 years (2006~2008). Main plot was consisted of application level of CCM such as 150%, 200% and control plot. The total day matter yield (DMY) of Italian ryegrass and WCR in treatment of CCM 150% and CCM 200% significantly decreased as compared with that of treatment of chemical fertilizer (CF). However, NDF, AND and CP content of Italian rye grass and WCR were hardly influenced by CCM application.
        219.
        2009.08 구독 인증기관·개인회원 무료
        The experimental work was conducted to investigate the effects of the application level of composted cattle manure (CCM) on forage productivity using rye-whole crop rice (WCR) double cropping system for 3 years. Main plot was consisted of application level of CCM such as 150%, 200% and control plot. The total DMY of of rye-WCR in treatment of CCM 150% significantly decreased as compared with that of treatment of CF and CCM 200%. However, NDF, ADF and CP content of rye and WCR were hardly influenced by CCM application.
        220.
        2009.08 구독 인증기관·개인회원 무료
        This study was carried out to investigate the properties of soil and water under Double-cropping SSH followed by whole crop barley (SSFWB) or by Hairy vetch (SSFHV) in paddy land. A field study was conducted at Baeksan-myeon, Kimje, Jeonbuk province in Korea on clay loam soil for 3 years. All plots were arranged in completely randomized design with three replicates. The pH and the contents of T-N and organic matter (OM) in soil samples collected at the end of the experiment were remarkably higher t㏊n those at the beginning of the experiment in both SSFWB and SSFHV treatment (P<0.05). The contents of an exchangeable cations at the end of the experiment were remarkably higher t㏊n those at the beginning of the experiment in both SSFWB and SSFHV (P<0.05). And then, the concentration of NO₃-N, NH₃-N and PO₄-P in discharge and leaching water were not influenced by the cropping system