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        검색결과 221

        61.
        2017.04 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        We investigate two abnormal CME-Storm pairs that occurred on 2014 September 10 - 12 and 2015 March 15 - 17, respectively. The first one was a moderate geomagnetic storm (Dstmin  -75 nT) driven by the X1.6 high speed flare-associated CME (1267 km s−1) in AR 12158 (N14E02) near solar disk center. The other was a very intense geomagnetic storm (Dstmin  -223 nT) caused by a CME with moderate speed (719 km s−1) and associated with a filament eruption accompanied by a weak flare (C9.1) in AR 12297 (S17W38). Both CMEs have large direction parameters facing the Earth and southward magnetic field orientation in their solar source region. In this study, we inspect the structure of Interplanetary Flux Ropes (IFRs) at the Earth estimated by using the torus fitting technique assuming self-similar expansion. As results, we find that the moderate storm on 2014 September 12 was caused by small-scale southward magnetic fields in the sheath region ahead of the IFR. The Earth traversed the portion of the IFR where only the northward fields are observed. Meanwhile, in case of the 2015 March 17 storm, our IFR analysis revealed that the Earth passed the very portion where only the southward magnetic fields are observed throughout the passage. The resultant southward magnetic field with long- duration is the main cause of the intense storm. We suggest that 3D magnetic field geometry of an IFR at the IFR-Earth encounter is important and the strength of a geomagnetic storm is strongly affected by the relative location of the Earth with respect to the IFR structure.
        4,200원
        74.
        2014.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The objective of this study was to know the in vitro effects of supplemental anthelmintic plant extracts on the inhibition of protozoa for reducing methane production in the rumen. A fistulated Holstein cow was used as a donor of rumen fluid. The plant extracts (Lonicera japonica, Zanthoxylum piperitum, Pyrethrum, Torreya nucifera, Ruta graveolens) known to have anthelmintic effect were added to the in vitro fermentation bottles containing the rumen fluid and medium. The rumen protozoal population was depressed by the addition of Pyrethrum, Torreya nucifera and Ruta graveolens. The methane production was also significantly (p<0.05)reduced by addition of Pyrethrum (2.20 ml/g DM), Torreya nucifera (2.36 ml/g DM) and Ruta graveolens (2.20 ml/g DM). The microbial growth in the treatments of Ruta graveolens or anthoxylum piperitum was the greatest after 12 h and 24 h incubations, respectively. The results of this study indicated that anthelmintic plant extracts appeared to reduce methane production by inhibition of ruminal protozoa related with the methanogens living endosymbiotic in protozoal cells.
        4,000원
        75.
        2013.10 구독 인증기관·개인회원 무료
        Withthe increasing trend of global trades and protection of agro-ecosystem in importing and exporting countries against quarantine pest, quarantine and pre-shipment(QPS) fumigation in perishable commodities is now more important to maintain postharvest quality until delivering to end user not just eradiation of quarantine pest. However, there are limited use of MB fumigation on export fruits and vegetables due to phytotoxic damages of fumigated one. VapormateTM, alternative to methyl bromide(MB), a gas formulation of ethyl formate(EF) with carbon dioxide, is commercially in use for imported fruits fumigation such as bananas and lemon. Herein, based on previous preliminary studies, scale-up and commercial scale fumigation of ethyl formate is presented for promising export paprika and tomato. Efficacy of ethyl formate was described in terms of concentration × time (CT) products to Myzus persicae for paprika and Bemisia tabaci for tomato.
        76.
        2013.10 구독 인증기관·개인회원 무료
        Since Montreal protocol in1989 designated MB(methyl bromide) as ozone depleting chemicals, IPPC(International Plant Protection Convention) has adopted replacing the MB with alternative chemical and reducing the rate of MB use in plant quarantine in 2008. Pineapples are one of the most frequently fumigated imported fruit with MB in Korea. However, there was no technically available replacement. Therefore, we evaluated phosphine(PH3) fumigation as alternative to MB in applying pineapples. In the preliminary test, PH3 gas in 12L desicators to calculate ranged to 0.1 from 2g/m3 was tested at 2 and 24hr exposure to target pest, citrus mealy bug(CMB, Planococcus citri). All different of stage of CMB was shown 100% mortality when 2g/m3 of PH3 applied for 24hrs at 8℃. To confirm studies designed in 0.5m3 fumigation chamber, all egg, nymph and adult stages of CMB was killed completely and there wasn’t any phytotoxic and quality damages on pineapples for 2 weeks post-fumigation periods at 8℃. In terms of commercial use, further commercial research will need to be carry out in cooperation with importers and fumigators.
        79.
        2012.06 구독 인증기관·개인회원 무료
        Cryopreservation of canine spermatozoa affords potential exchange of genetic material, and thus may lead to improvement in the breeding management. However, canine spermatozoa undergo many damages such as, cold shock, ice crystal formation, oxidative stress during cryopreservation. In this study used the CASA for investigating the effect of various trehalose concentrations and thawing temperatures on the sperm viability. In addition, the efficacy of the most optimal of the tested cryopreservation protocols in this study was verified by AI as the in vivo test. Also, this study evaluates the variation of frozen- thawed canine spermatozoa during different incubation condition. The addition of trehalose 25 mM was optimal concentration and frozen-thawed semen quality was significantly higher better than control (Glucose) and other concentration groups. In effect of thawing temperature on frozen-thawed sperm movement and intact acrosome evaluations, which result enhance the sperm motility and movement value depending on increase temperature condition at 36, 54 and 72℃. Also, in the effect of different incubation condition on frozen-thawed sperm after thawing at 36℃ for 60 sec, that the results trehalose 25 mM was significantly better (p<0.05) than glucose in general as well as, the post-thawed sperm motility and intact acrosome was reduced depending on increase the incubation time. Especially, incubation at 4 to 8 hour was rapidly depreciation of movement value and the rate of intact acrosome was dropped similar tendency. Thus, incubation 17℃ was better than other incubation groups on sperm motility and acrosome integrity. For the in vivo evaluate of spermatozoa survival and is the most definitive test of sperm function, we performed artificial insemination in estrous bitch. The semen was prepared for intrauterine insemination using the 25 mM trehalose freezing extender and thawing at 36℃, and 2 bitches were inseminated with 1×106 motile spermatozoa by surgical method. The results of AI, the pregnancy rates, mean litter size and oocyte fertilization rate were 16.6% (1/6), and 50% (2/4), respectively. In conclusion, based on the results of these experiments, the effect of addition of trehalose on extender improves the movement and intact acrosome of frozen-thawed semen. In particular, trehalose 25 mM groups was higher than other different concentration group on movement value and acrosome integrity of frozen-thawed sperm. Also, through incubation condition, this study identify the optimal incubation temperature after thawing was 17℃. Furthermore, the information will be contributed to develop the canine ART including AI, IVF and canine ICSI. * This research was supported by iPET (Grants 110056-3), Ministry for Food, Agriculture, Forestry and Fisheries, Republic of Korea.
        80.
        2011.10 구독 인증기관·개인회원 무료
        Cell transplantation therapy using adult stem cells has recently been identified as a potential treatment for spinal cord injury (SCI). But, recovery after traumatic SCI is very limited. As dogs are physiologically much more similar to human compared with other traditional mammalian models in disease presentation and clinical responses, a number of researches demonstrated canis familiaris is a suitable model for human diseases. This study investigated the effect of transplantation of canine Mesenchymal Stem Cells (cMSC) and neural-induced cMSC (nMSC) to understand how these cells improve neurological function in canine SCI model. The differentiation of cMSC into neural precursor cells was induced in dulbecco’s modified eagle’s medium supplemented with N2-supplement, dibutyryl cyclic adenosine monophosphate, and butylated hydroxyanisole. SCI was induced between T1 and T2 by surgical hemi-section in adult dogs, and then assigned to two groups according to the applied cell types (cMSC vs nMSC). Pelleted cMSC or nMSC were transplanted directly into the injured site after SCI, respectively. Analysis of motor function after transplantation was evaluated by modified Olby score. Magnetic resonance imaging (MRI), histological and immunohistichemical analysis were also performed. Functional recovery in group of cMSC was increasing gradually after transplantation and was higher than nMSC. In MRI, we could not confirm any difference between the cMSC and nMSC experimental groups. Immunohistochemically, beta3-tubuline and nestin were observed in injury site of two experimental groups with the expression level close to non-injured groups. Transplantation of mesenchymal stem cells could promote neuronal reconstruction and repair motor function in SCI. These showed mesenchymal stem cells could be a great candidate as a therapeutic tools in degeneration disease, and dogs could be used to explore human regenerative medicine as a promising animal model. This research was supported by iPET (Grants 110056032CG000), Ministry for Food, Agriculture, Forestry and Fisheries, Republic of Korea.
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