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排序方式: 共有199条查询结果,搜索用时 15 毫秒
101.
102.
Eun-Ok Jeon Jong-Nyeo Kim Hae-Rim Lee Bon-Sang Koo Kyeong-Cheol Min Moo-Sung Han Seung-Baek Lee Yeon-Ji Bae Jong-Suk Mo Sun-Hyung Cho Chang-Hee Lee In-Pil Mo 《Journal of veterinary science (Suw?n-si, Korea)》2014,15(4):579-582
Eggs exhibiting eggshell apex abnormalities (EAA) were evaluated for changes in shell characteristics such as strength, thickness, and ultrastructure. Mycoplasma synoviae (MS) infection was confirmed by serological assay along with isolation of MS from the trachea and oviduct. Changes in eggshell quality were shown to be statistically significant (p < 0.01). We also identified ultrastructural changes in the mammillary knob layer by Scanning Electron Microscopy. While eggs may seem to be structurally sound, ultrastructural evaluation showed that affected eggs do not regain their former quality. In our knowledge, this is the first report describing the occurrence of EAA in Korea. 相似文献
103.
In order to assess the potential of the hydroxy-containing polyamic acid (PHAA) synthesized from 3,3′-dihydroxy benzidine
and pyromellitic dianhydride for a fire-safe polymer, the cyclization pathway of PHAA has been investigated using a model
compound prepared from 2-aminophenol and phthalic anhydride. The reaction was monitored by1H-nuclear magnetic resonance. N-(2-hydroxyphenyl)phthalamic acid is converted to N-(2-hydroxyphenyl)phthalimide at ca. 175°C,
showing endothermic reaction. The imide structure is rearranged to the benzoxazole structure over ca. 400°C. These results
are similar with that of PHAA. According to pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS) data, water and carbon
dioxide are released during the cyclization and rearrangement reaction. One DMAc molecule is complexed with one carboxyl acid
group in PHAA, which accelerates the imidization process to release more easily the flame retardant, water. 相似文献
104.
The effect of functional under-layer on muscle activity and exercise performance was investigated on the basis of physiological tests and electromyography (EMG). EMG was used to study muscle activity during exercise after fitting compressional under-layer. We observed slight differences in the results of anaerobic and aerobic muscle EMG tests among subjects because of differences in body muscle content. In addition, muscle activity was varied according to muscle parts used during the physiological tests with fitting the functional under-layer. We suggest that compressional under-layer decreases muscle vibration and improves blood circulation, resulting in overall improved muscle activity on the basis of the usage of different muscles in each type of exercise. However, future studies are needed to evaluate the long-term effects of the functional under-layer. 相似文献
105.
Hyun Jin Koo Gap Shik Chang Seong Hun Kim Wan Gyu Hahm Seong Yoon Park 《Fibers and Polymers》2013,14(12):2083-2087
Mechanical properties and the long-term degradation properties of the recycled PET yarns are typically lower than the virgin PET yarns due to the contaminants coming from non-PET bottles, labels and caps etc. For environmental reasons, recycling of post-consumer polyester bottles into textile fibers has become commercially attractive. We studied mechanical and chemical recycling processes and examined their effects on yarn properties such as tensile properties, thermal characteristics, hydrolysis and photo-degradation. It was found that the virgin and the chemical recycled yarns with sufficient purification show similar processability, physical and mechanical properties, and long-term degradation behavior. The results provide useful information on recycled PET yarns for processability and serviceability for the high-end use. 相似文献
106.
Lobo MK Covington HE Chaudhury D Friedman AK Sun H Damez-Werno D Dietz DM Zaman S Koo JW Kennedy PJ Mouzon E Mogri M Neve RL Deisseroth K Han MH Nestler EJ 《Science (New York, N.Y.)》2010,330(6002):385-390
The nucleus accumbens is a key mediator of cocaine reward, but the distinct roles of the two subpopulations of nucleus accumbens projection neurons, those expressing dopamine D1 versus D2 receptors, are poorly understood. We show that deletion of TrkB, the brain-derived neurotrophic factor (BDNF) receptor, selectively from D1+ or D2+ neurons oppositely affects cocaine reward. Because loss of TrkB in D2+ neurons increases their neuronal excitability, we next used optogenetic tools to control selectively the firing rate of D1+ and D2+ nucleus accumbens neurons and studied consequent effects on cocaine reward. Activation of D2+ neurons, mimicking the loss of TrkB, suppresses cocaine reward, with opposite effects induced by activation of D1+ neurons. These results provide insight into the molecular control of D1+ and D2+ neuronal activity as well as the circuit-level contribution of these cell types to cocaine reward. 相似文献
107.
Etienne Baras Grace V. Montalvan Naranjos Dustin V. Silva del Aguila Fred Chu Koo Rémi Dugué Carlos Chavez Fabrice Duponchelle Jean‐François Renno C. Carmen Garcia‐Dávila Jesus Nuñez 《Aquaculture Research》2012,43(12):1764-1776
Food intake (FI) and gut evacuation (Rg) were measured in larvae of Pseudoplatystoma punctifer (4.5–18.4 mm SL) fed Artemia nauplii, taking advantage of the translucence of their abdominal region to achieve this in a non‐destructive way, using digital photographs and mathematical reconstruction of gut volume content (ellipsoidal and cylindrical models for stomach and intestine respectively). The inaccuracy of the method, with reference to counts of nauplii following fish dissection, was low (2.9 ± 1.5%) and independent of fish size (P = 0.6153). Pigmentation hampered measurement in fish >18–19 mm SL. Anaesthesia was needed in fish >9.5 mm SL, thereby preventing the measurement of Rg in individual fish. The FI increased rapidly during the ontogeny, passing from <7% M at 0.6 mg, to 14% M at 1 mg and 21% M at 15–40 mg, and then decreased slightly in larger fish. At 28.5°C, Rg (% M h?1) was modelled as Rg = ?8.22 + 12.11 log FI + 6.30 log M – 12.67 (log M)2 (R2 = 0.904, d.f. = 27, with FI in% M and M in mg). Extrapolations of Rg over 24 h gave estimates of daily food rations that fit well with those measured in cannibalistic P. punctifer. 相似文献
108.
Jung Dae Lim Sung Ryul Lee Taeseong Kim Seon-A Jang Se Chan Kang Hyun Jung Koo Eunsoo Sohn Jong Phil Bak Seung Namkoong Hyoung Kyu Kim In Sung Song Nari Kim Eun-Hwa Sohn Jin Han 《Marine drugs》2015,13(2):1051-1067
Fucoidan is an l-fucose-enriched sulfated polysaccharide isolated from brown algae and marine invertebrates. In this study, we investigated the protective effect of fucoidan from Fucus vesiculosus on alcohol-induced murine liver damage. Liver injury was induced by oral administration of 25% alcohol with or without fucoidan (30 mg/kg or 60 mg/kg) for seven days. Alcohol administration increased serum aspartate aminotransferase and alanine aminotransferase levels, but these increases were suppressed by the treatment of fucoidan. Transforming growth factor beta 1 (TGF-β1), a liver fibrosis-inducing factor, was highly expressed in the alcohol-fed group and human hepatoma HepG2 cell; however, the increase in TGF-β1 expression was reduced following fucoidan administration. Treatment with fucoidan was also found to significantly reduce the production of inflammation-promoting cyclooygenase-2 and nitric oxide, while markedly increasing the expression of the hepatoprotective enzyme, hemeoxygenase-1, on murine liver and HepG2 cells. Taken together, the antifibrotic and anti-inflammatory effects of fucoidan on alcohol-induced liver damage may provide valuable insights into developing new therapeutics or interventions. 相似文献
109.
110.
Soo Jeong Kwon Swapan Kumar Roy Hye-Rim Kim Young-Ja Moon Sun Hee Woo Hee Ock Boo Jin-Woog Koo Hag Hyun Kim 《Journal of Crop Science and Biotechnology》2018,21(2):121-127
This study aimed to evaluate the effects of soil types and environmental factors for optimum conditions of seedlings growth of the Platycodon grandiflorum for establishing the in vivo acclimatization system of regenerated plants derived from the in vitro culture. P. grandflorum seedlings were transferred to the in vivo condition and acclimatized under different soil types, light intensities, and various temperatures. Changes caused by environmental factors and soil types in plant growth viz. plant height, leaf width, leaf length, stem diameter, number of leaves, branches and nodes were recorded in this study. Among the nine types of soil, the best growth performances were obtained from the soil type SVP (Soil mixed with horticultural bed soil, vermiculite, and perlite @ 2:1:1). Seedlings of P. grandiflorum showed the best growth at higher levels of light intensity (60 μmol·m-2·s-1). In contrast, P. grandiflorum seedlings showed the best growth response at a moderate level of temperature (25°C). Collectively, the present study provides a better understanding of the responses of growth characteristics in P. grandiflorum seedlings exposed to various soil types, light intensities, and temperatures. 相似文献