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排序方式: 共有433条查询结果,搜索用时 15 毫秒
71.
Dae Sub Song Youn Jeong Lee Ok Mi Jeong Yong Joo Kim Chan Hee Park Jung Eun Yoo Woo Jin Jeon Jun Hun Kwon Gun Woo Ha Bo Kyu Kang Chul Seung Lee Hye Kwon Kim Byeong Yeal Jung Jae Hong Kim Jin Sik Oh 《Journal of veterinary science (Suw?n-si, Korea)》2009,10(4):323-329
Active serologic surveillance is necessary to control the spread of the avian influenza virus (AIV). In this study, we evaluated a commercially-available cELISA in terms of its ability to detect AIV antibodies in the sera of 3,358 animals from twelve species. cELISA detected antibodies against reference H1- through H15-subtype AIV strains without cross reactivity. Furthermore, the cELISA was able to detect antibodies produced following a challenge of the AIV H9N2 subtype in chickens, or following vaccination of the AIV H9 or H5 subtypes in chickens, ducks and geese. Next, we tested the sensitivity and specificity of the cELISA with sera from twelve different animal species, and compared these results with those obtained by the hemagglutination-inhibition (HI) test, the "gold standard" in AIV sera surveillance, a second commercially-available cELISA (IZS ELISA), or the agar gel precipitation (AGP) test. Compared with the HI test, the sensitivities and specificities of cELISA were 95% and 96% in chicken, 86% and 88% in duck, 97% and 100% in turkey, 100% and 87% in goose, and 91% and 97% in swine, respectively. The sensitivities and specificities of the cELISA in this study were higher than those of IZS ELISA for the duck, turkey, goose, and grey partridge sera samples. The results of AGP test against duck and turkey sera also showed significant correlation with the results of cELISA (R-value >0.9). In terms of flock sensitivity, the cELISA correlated better with the HI test than with commercially-available indirect ELISAs, with 100% flock sensitivity. 相似文献
72.
A melt-process was used to prepare high molecular weight Poly(vinyl chloride) (PVC) films without the use of a conventional
plasticizer and heat stabilizer. Rigid PVC powder was swollen with dimethylformamide containing 4∼10 vol% water to reduce
its melting temperature. The swollen powder was pressed at a relatively low temperature of 75∼125 °C to form a film shape,
and then washed and dried. The visible light transmittance, X-ray diffraction, density and the tensile properties of the resulting
films were examined to estimate the success or failure of film formation. The films could be produced by not only the melt-process
but also a compression-process using the rigid, highly swollen PVC powder. The resulting films had no voids, which are generally
observed in PVC products formed by a solution process. The minimum temperature for these processes decreased with decreasing
water content in the mixture: The minimum temperatures according to the water content in the mixture to produce faultless
films through the melt-process were 4 %–105 °C, 6 %–115 °C, 8 and 10 %–125 °C, while those through the compression process
were 4 %–95 °C, 6 and 8 %–105 °C, 10 %–115 °C. 相似文献
73.
This study developed a novel PHB-lignin-jute biodegradable composite with preferable mechanical properties and low water absorption.
The appearances of fracture surface of composites were analyzed by scanning electron microscope. The result suggested a Gaussian-like
distribution of the size particles supporting the presence of lignin with a radius smaller than 0.5 μm. According to X-ray
diffraction, the presence of lignin and jute fibers was decreased the crystallization of PHB. Moreover, the glass transition
temperature of PHB increased, and the endotherm during glass transition was decreased. The maximum tensile strength and modulus
of composites were obtained with 30 wt% jute fiber contents and 4 wt% lignin contents. The presence of jute fibers was largely
increased the water absorption of composites. However, the presence of lignin was effectively decreased the water absorption
of composites at saturation levels. 相似文献
74.
Joo Ran KimSuraj Sharma 《Industrial Crops and Products》2012,36(1):485-499
This study investigates the development of thermoset plastics from plant-based oils (e.g., linseed, soybean, cottonseed, oilseed radish, and peanut oils) using an optimal process of solvent-free epoxidation. The epoxidation of plant oils can be accomplished economically by reacting the double bonds of fatty-acids with hydrogen peroxide. During the solvent-free process catalyzed by the ion-exchange resin, we observed that the influence of several variables was important: the molar ratio of hydrogen peroxide to unsaturation, acetic acid to unsaturation, and temperature. The epoxidation of plant oils was determined from the liquid mixture and the composite matrix by thermal and spectroscopic analyses. Compounds with a higher double-bond (iodine) value showed higher oxirane oxygen percent and selectivity, and a higher hydroxyl value because of a greater possibility of attack by solutions causing side reactions. Lower iodine values indicated fewer epoxy groups and selectivity, and a lower hydroxyl value. Benzyl pyrazinium hexafluoroantimonate (BPH) yielded good thermal curing properties; as little as 1% added to the plastics produced light-weight composites. Epoxidized linseed oil promises the highest modulus and impact resistance due to the largest number of double bonds to contribute more epoxy groups and the large proportion of linolenic acids to produce epoxy groups rapidly. 相似文献
75.
Sunhee Shin Seong Soo Joo Jeong Hee Jeon Dongsun Park Min-Jung Jang Tae-Ook Kim Hyun-Kyu Kim Bang Yeon Hwang Ki-Yon Kim Yun-Bae Kim 《Journal of veterinary science (Suw?n-si, Korea)》2010,11(3):273-275
Anti-inflammatory effects of Houttuynia cordata supercritical extract (HSE) were investigated in a carrageenan-air pouch model. HSE (200 mg/kg, oral) suppressed exudation and albumin leakage, as well as inflammatory cell infiltration. Dexamethasone (2 mg/kg, i.p.) only decreased exudation and cell infiltration, while indomethacin (2 mg/kg, i.p.) reduced exudate volume and albumin content. HSE lowered tumor-necrosis factor (TNF)-α and nitric oxide (NO), as well as prostaglandin E2 (PGE2). Dexamethasone only reduced TNF-α and NO, while indomethacin decreased TNF-α and PGE2. The suppressive activity of HSE on NO and PGE2 production was confirmed in RAW 264.7. These results demonstrate that HSE exerts anti-inflammatory effects by inhibiting both TNF-α-NO and cyclooxygenase II-PGE2 pathways. 相似文献
76.
Ko JA Kim YM Ryu YB Jeong HJ Park TS Park SJ Wee YJ Kim JS Kim D Lee WS 《Journal of agricultural and food chemistry》2012,60(24):6210-6216
Rubusoside (R) is a natural sweetener and a solubilizing agent with antiangiogenic and antiallergic properties. However, currently, its production is quite expensive, and therefore, we have investigated nine commercially available glycosidases to optimize an economically viable R-production method. A stevioside (ST)-specific β-glucosidase (SSGase) was selected and purified 7-fold from Aspergillus aculeatus Viscozyme L by a two-step column chromatography procedure. The 79 kDa protein was stable from pH 3.0 to pH 7.0 at 50-60 °C. Hydrolysis of ST by SSGase produced R and steviol monoglucosyl ester as determined by (1)H and (13)C nuclear magnetic resonance (NMR). Importantly, SSGase showed higher activity toward ST than other β-linked glucobioses. The optimal conditions for R production were 280 mM ST and 16.6 μL of SSGase at pH 5.1 and 63 °C. This is the first discussion detailing the production of R by enzymatic hydrolysis of ST and is useful for the food additive and pharmaceutical industries. 相似文献
77.
Chang?Hoon?Lee Sang?Yoon?Kim Maria?B.?Villamil Prabhat?Pramanik Chang?Ok?Hong Pil?Joo?KimEmail author 《Biology and Fertility of Soils》2012,48(4):435-442
Cultivation of green manure plants during the fallow season in rice paddy soil has been strongly recommended to improve soil
properties. However, green manuring may impact greenhouse gas emission, methane (hereafter, CH4) in particular, under the flooded rice cultivation and thus, application of chemical amendments being electron acceptors
can be an effective mitigation strategy to reduce CH4 emissions in irrigated rice (Oryza sativa L.) field amended with green manure. To investigate the effect of iron (Fe) slag silicate fertilizer (hereafter, silicate
fertilizer), which was effective in reducing CH4 emission and increasing rice productivity, in green manure-amended paddy soil, the aboveground biomass of Chinese milk vetch
(hereafter, vetch) was added at rates of 0, 10, 20, and 40 Mg (fresh weight) ha−1 before the application of silicate fertilizer, which was added at rates of 0 and 2.3 Mg ha−1. Silicate fertilization reduced the seasonal CH4 flux by ca. 14.5% and increased rice yield by ca. 15.7% in the control (no vetch application) treatment. However, CH4 production was increased by silicate fertilization in vetch-treated soil particularly at the initial rice growing stage,
which was probably due to the enhanced decomposition of added organic matters by the silicate liming effect. In conclusion,
silicate fertilization is not effective in reducing CH4 production in green manure-amended rice paddy soils and its use should be properly controlled. 相似文献
78.
Kyung?Min?Yoo Seok?Won?Lee Jae?Ryoun?YounEmail author Do?Heum?Yoon Young?Eun?Cho Jae-Pil?Yu Hyung?Sang?Park 《Fibers and Polymers》2003,4(2):89-96
A vertebral cage is a hollow medical device which is used in spine surgery. By implanting the cage into the spine column,
it is possible to restore disc and relieve pressure on the nerve roots. Most cages have been made of titanium alloys but they
detract the biocompatibility. Currently PEEK (polyether ether ketone) is applied to various implants because it has good properties
like heat resistance, chemical resistance, strength, and especially biocompatibility. A new shape of vertebral cage is designed
and injection molding of PEEK is considered for production. Before injection molding of the cage, it is needed to evaluate
process conditions and properties of the final product. Variables affecting the shrinkage of the cage are considered, e.g.,
injection time, packing pressure, mold temperature, and melt temperature. By using the numerical simulation program, MOLDFLOW,
several cases are studied. Data files obtained by MOLDFLOW analysis are used for stress analysis with ABAQUS, and shrinkage
and residual stress fields are predicted. With these results, optimum process conditions are determined. 相似文献
79.
Hyon MK Kwon E Choi HJ Kang BC 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》2011,73(6):739-745
There is a need for a new liver fibrosis model of immunodeficient mice to study the effects of cell therapy on liver disease because there are not many animal models available to study the effects of cell therapy. In this study, we induced liver fibrosis using dimethylnitrosamine (DMN) in NOD/SCID mice to create an animal model for liver disease. DMN (5 mg/kg, i.p.) was injected intraperitoneally for three consecutive days per week for 6 or 8 weeks, and the mice were sacrificed at weeks 0, 4 and 8 after the last DMN injection. The 6-week DMN-treated group gradually recovered from serum biochemical changes, histopathological toxic effects and lesions in the liver at weeks 4 and 8 after the last DMN injection. However, the progression of liver fibrosis and toxic levels were maintained in the 8-week DMN-treated group at week 4 after the last DMN injection. The increases in iron and extracellular matrix (collagen) in the DMN-treated group were confirmed by Prussian blue (PB) and Masson's trichrome (MT) staining, respectively. Additionally, activation of hepatic stellate cells was observed by alpha smooth muscle actin (α-SMA) immunostaining and western blot. In conclusion, treatment of NOD/SCID mice with 5 mg/kg of DMN for 8 weeks can be used to induce an appropriate animal model of disease for liver fibrosis. This model may be useful for evaluation of the efficacy and safety of cell therapies such as human mesenchymal stem cell therapy. 相似文献
80.
Ryu YB Jeong HJ Yoon SY Park JY Kim YM Park SJ Rho MC Kim SJ Lee WS 《Journal of agricultural and food chemistry》2011,59(12):6467-6473
Influenza A virus infections continue to pose a major threat to humans and several animal species. Neuraminidase (NA) is one of the most promising targets for the development of drugs against influenza viruses because of its critical role in the viral life cycle. During the course of a search for NA inhibitors from edible natural sources, we found that the ethyl acetate layer of ethanol extracts of Ecklonia cava showed extremely high NA-inhibitory activity (72.1% inhibition at 30 μg/mL). Bioactivity-guided fractionation of the ethyl acetate layer yielded five phlorotannins, identified as phloroglucinol (1), eckol (2), 7-phloroeckol (3), phlorofucofuroeckol (4), and dieckol (5). The inhibitory activities of these compounds (1-5) against NAs from group-1 (A/Bervig_Mission/1/18 [H1N1], A/PR/8/34 [H1N1]) and group-2 (A/Hong Kong/8/68 [H3N2], A/Chicken/Korea/MS96/96 [H9N2]) influenza A were evaluated to determine potencies and kinetic behavior. Analyses using various in vitro influenza A virus NA assays showed that all five phlorotannin derivatives were selective NA inhibitors. Of the phlorotannins, phlorofucofuroeckol (4) exhibited the most potent inhibitory activities toward group-1 NAs (IC?? values, 4.5 and 14.7 μM), whereas dieckol (5) potently inhibited group-2 NAs. Kinetic analyses indicated that compounds 1-5 were all noncompetitive. Notably, these noncompetitive inhibitors synergized with oseltamivir to enhance the NA-inhibitory effects of oseltamivir. 相似文献