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排序方式: 共有85条查询结果,搜索用时 93 毫秒
41.
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PC Rodriguez LB Valdez T Zaobornyj A Boveris MT Beconi 《Reproduction in domestic animals》2011,46(1):74-81
The aim of this work was to quantify NO, O2? and ONOO? production during heparin‐induced capacitation of cryopreserved bovine spermatozoa. A time dependent hyperbolic increase was observed for heparin‐dependent capacitation, O2 uptake, and NO production. Conversely, O2? production was increased during the first 15 min of incubation, showing a decrease from this time until 45 min. At 15 min of heparin incubation, a threefold increase in O2 consumption (5.9 ± 0.6 nmol/min × 107 cells), an enhancement in NO release (1.1 ± 0.2 nmol/min × 107 cells), and a five‐fold increase in O2? production (1.3 ± 0.07 nmol/min × 107 cells), were observed. Peroxynitrite production rate was estimated taking into account NO and O2? generation and the second‐order rate constant of the reaction between these species. To conclude, heparin‐induced capacitation of cryopreserved bovine spermatozoa activates (i) mitochondrial O2 uptake by high ADP levels due to increased energy requirements, (ii) NO production by a constitutive NOS and (iii) O2? production by a membrane‐bound NAD(P)H oxidase. The products of both enzymes are released to the extracellular space and could be involved in the process of sperm capacitation. 相似文献
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Performance characteristics of the turbidimetric ACL‐TOP CTS 300 coagulation analyzer in dogs and cats 下载免费PDF全文
45.
Effect of Salinity on Growth Parameters,Soil Water Potential and Ion Composition in Cucumis melo cv. Huanghemi in North‐Western China 下载免费PDF全文
A. Tedeschi L. Zong C. H. Huang L. Vitale M. G. Volpe X. Xue 《Journal of Agronomy and Crop Science》2017,203(1):41-55
A field trial conducted on the melon cultivar Huanghemi irrigated with saline water was carried out in Minqin County in the 2‐year period, 2007 and 2008. In three irrigation treatments, different saline water concentrations were applied, that is 0.8 g l?1 (Control C), 2 g l?1 (Treatment S1) and 5 g l?1 (Treatment S2), reproducing the natural groundwater concentration in the county. The electrical conductivity of the saline water was as follows: 1.00, 2.66 and 7.03 dS m?1, respectively. The aims of the study were (i) to monitor water consumption and water potential, (ii) assess, during the whole crop cycle, some growth parameters and their relations for estimating the morpho‐functional plant response irrigated with saline water and (iii) determine the ion concentration in different plant tissues to evaluate which mechanism the plant activates in the presence of high salt concentrations. Under salinity stress, the plants sustained the concentration of Ca, Mg and K, but at a level not sufficient to limit the Na adsorption. Therefore, the melon yield decreased and it was determined by a displacement of the ratio K/Na and by a lower (total potential MPa). Consequently with increasing salinity, a significant reduction was observed in: water consumption (ET c, mm), leaf area duration (LAD, m2 d), on shoot dry weight aboveground (W , g plant?1), on specific leaf area (SLA, cm2 g?1) and on leaf area ratio (LAR, cm2 g?1). In treatment S2, in addition to these changes which mainly affected the plant morphology with effects on the biomass produced, a moderate reduction was also observed in net assimilation rate (NAR, g m?2 d?1), water use efficiency (WUE), a significant reduction in the energy conversion efficiency (ECE, %) and, in short, in a reduction in the relative growth rate (RGR, g g?1 d?1). 相似文献
46.
Cometa MF Fortuna S Palazzino G Volpe MT Rengifo Salgado E Nicoletti M Tomassini L 《Fitoterapia》2012,83(3):476-480
The phytochemical study of the stem bark and wood of Abuta grandifolia (Mart.) Sandwith led to the identification of four bisbenzylisoquinoline alkaloids (BBIQs), namely (R,S)-2 N-norberbamunine (1), (R,R)-isochondodendrine (2), (S-S)-O4″-methyl, Nb-nor-O6'-demethyl-(+)-curine (3), and (S-S)-O4″-methyl, O6'-demethyl-(+)-curine (4), together with the aporphine alkaloid R-nornuciferine (5), all obtained by countercurrent distribution separation (CCD) and identified on the basis of their spectroscopic data. Alkaloids 3 and 4 were new. All the isolated compounds were tested for acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) inhibitory activities. 1 was the most active against AChE, whereas 3 and 4 were the most potent against BChE. Interestingly, all tested alkaloids are more potent against BChE than against AChE. This selectivity of cholinesterase (ChE) inhibition could be important in order to speculate on their potential therapeutic relevance. 相似文献
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Cognitive interaction after staged callosal section: evidence for transfer of semantic activation 总被引:4,自引:0,他引:4
J J Sidtis B T Volpe J D Holtzman D H Wilson M S Gazzaniga 《Science (New York, N.Y.)》1981,212(4492):344-346
Sensory and cognitive functions were assessed in a right-handed male before and after partial and complete callosal commissurotomy. After the initial posterior section was made, there was no evidence of interhemispheric sensory transfer, although the left hemisphere did have access to stimulus-related semantic and episodic information from the right hemisphere. After the callosum was completely sectioned, this exchange was no longer observed. 相似文献
49.
MK Gagan LK Ayliffe D Hopley JA Cali GE Mortimer J Chappell MT McCulloch MJ Head 《Science (New York, N.Y.)》1998,279(5353):1014-1018
Skeletal Sr/Ca and 18O/16O ratios in corals from the Great Barrier Reef, Australia, indicate that the tropical ocean surface approximately 5350 years ago was 1 degrees C warmer and enriched in 18O by 0.5 per mil relative to modern seawater. The results suggest that the temperature increase enhanced the evaporative enrichment of 18O in seawater. Transport of part of the additional atmospheric water vapor to extratropical latitudes may have sustained the 18O/16O anomaly. The reduced glacial-Holocene shift in seawater 18O/16O ratio produced by the mid-Holocene 18O enrichment may help to reconcile the different temperature histories for the last deglaciation given by coral Sr/Ca thermometry and foraminiferal oxygen-isotope records. 相似文献
50.
Gonad quality of sea urchin Paracentrotus lividus cultured in an offshore pilot‐scale trial on the south‐east Italian coast 下载免费PDF全文
M.G. Volpe A. Fabbrocini F. Siano E. Coccia G. Scordella C. Licchelli F. De Sio M. Paolucci 《Aquaculture Nutrition》2018,24(5):1444-1455
A pilot project aimed at testing roe enhancement strategies based on offshore Paracentrotus lividus cultures was conducted off the south‐east coast of Italy (Apulia Region). Adult sea urchins were reared in sea cages located 700 m offshore at a depth of 12 m for 3 months. The animals were fed once a week on two formulated diets, prepared mixing nutrients with agar 20 g/Kg and differing only in terms of the protein source: anchovy flour (Diet A) or krill flour (Diet K). At the end of the rearing trial, the gonad somatic index of sea urchins fed on formulated diets significantly exceeded that of wild sea urchins. Total FAA content in the gonads of wild sea urchins and Diet A‐fed sea urchins was similar, whereas in Diet K‐fed sea urchins it was significantly higher. In terms of fatty acids, the gonads contained SFAs, MUFAs and PUFAs. In visual and sensory assessment of gonads by panel test and electronic nose, the gonads of reared sea urchins were rated as being of better size, while no differences were recorded for coloration, taste and odour. This study shows that under these experimental conditions, commercial‐grade Paracentrotus lividus roe enhancement can be achieved after 3 months in sea cages. 相似文献