排序方式： 共有37条查询结果，搜索用时 15 毫秒
31.
Impact of feed solution flow rate on Peptide fractionation by electrodialysis with ultrafiltration membrane 总被引：1，自引：0，他引：1
Recently, processes combining an electrical field as a driving force to porous membranes have been developed for the separation of protein or peptide mixtures to obtain more purified products with higher functionality or nutritional value. The objective of this work was to evaluate the influence of the flow rate on the productivity and selectivity as well as on the electrodialytic parameters of electrodialysis with an ultrafiltration membrane (EDUF) during the fractionation of peptides from a beta-lactoglobulin tryptic hydrolysate. It appeared that the feed solution flow rate had no impact on the yield of the process but induced changes in the selectivity. In fact, increases in the flow rate decreased the migration of the peptides with limited electrophoretic mobility. 相似文献
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Previously undescribed third-stage larvae of two species of Spirurida were found in the haemocoel of the stalk-eyed mud crab Macrophthalmus hirtipes (Heller) (Ocypodidae) in New Zealand. Examinations by light and scanning electron microscopy showed that the larger larvae (about 7 mm long) belonged to a species of Ascarophis van Beneden, 1871 (Cystidicolidae), the genus including parasites of fishes, whereas the smaller larvae (about 4-5 mm long) belonged to the Acuariidae, a family with species parasitic as adults mostly in aquatic birds. In a sample of 82 specimens of M. hirtipes collected in July 2002 from Papanui Inlet, on Otago Peninsula, South Island, 74 crabs (90.2%) were infected with larval nematodes with an intensity of 1-18 (mean 4.6) nematodes per crab; no distinction between nematode species was made in these estimates, although juvenile Acuariidae greatly outnumbered larval Ascarophis. Apparently, crabs play a role as intermediate hosts of these nematode species. This is the first record of larval representatives of Cystidicolidae and Acuariidae from invertebrates in the Australasian Region. 相似文献
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Macroscopic fibers and ribbons of oriented carbon nanotubes 总被引：1，自引：0，他引：1
Vigolo B Pénicaud A Coulon C Sauder C Pailler R Journet C Bernier P Poulin P 《Science (New York, N.Y.)》2000,290(5495):1331-1334
A simple method was used to assemble single-walled carbon nanotubes into indefinitely long ribbons and fibers. The processing consists of dispersing the nanotubes in surfactant solutions, recondensing the nanotubes in the flow of a polymer solution to form a nanotube mesh, and then collating this mesh to a nanotube fiber. Flow-induced alignment may lead to a preferential orientation of the nanotubes in the mesh that has the form of a ribbon. Unlike classical carbon fibers, the nanotube fibers can be strongly bent without breaking. Their obtained elastic modulus is 10 times higher than the modulus of high-quality bucky paper. 相似文献
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Parasitism, water temperature and life history characteristics of the freshwater fish Gobiomorphus breviceps Stokell (Eleotridae) 总被引：1，自引：0，他引：1
Abstract – Life history traits can vary among populations of the same fish species in response to selective pressures exerted by the local environment. Here we used inter-population comparisons to investigate the effects of parasitism and variability in water temperature on life history traits in a New Zealand freshwater fish, the upland bully. Although age and size at maturity varied among populations, they were not significantly related to either temperature regime or average parasite load. Trade-offs between egg size and clutch size were only apparent in one of the seven populations when populations were analyzed separately but became clear when all data were pooled. However, neither average population clutch size or egg size was related to the population's mean parasite load or the local temperature regime. Although the latter two parameters may influence other life history variables, such as the number of clutches produced per season and the partitioning of eggs among clutches, there was no evidence that they influenced life history strategies of the upland bully populations investigated here. Note 相似文献
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Mukhtar MS Carvunis AR Dreze M Epple P Steinbrenner J Moore J Tasan M Galli M Hao T Nishimura MT Pevzner SJ Donovan SE Ghamsari L Santhanam B Romero V Poulin MM Gebreab F Gutierrez BJ Tam S Monachello D Boxem M Harbort CJ McDonald N Gai L Chen H He Y;European Union Effectoromics Consortium Vandenhaute J Roth FP Hill DE Ecker JR Vidal M Beynon J Braun P Dangl JL 《Science (New York, N.Y.)》2011,333(6042):596-601
Plants generate effective responses to infection by recognizing both conserved and variable pathogen-encoded molecules. Pathogens deploy virulence effector proteins into host cells, where they interact physically with host proteins to modulate defense. We generated an interaction network of plant-pathogen effectors from two pathogens spanning the eukaryote-eubacteria divergence, three classes of Arabidopsis immune system proteins, and ~8000 other Arabidopsis proteins. We noted convergence of effectors onto highly interconnected host proteins and indirect, rather than direct, connections between effectors and plant immune receptors. We demonstrated plant immune system functions for 15 of 17 tested host proteins that interact with effectors from both pathogens. Thus, pathogens from different kingdoms deploy independently evolved virulence proteins that interact with a limited set of highly connected cellular hubs to facilitate their diverse life-cycle strategies. 相似文献
37.
Miaudet P Derré A Maugey M Zakri C Piccione PM Inoubli R Poulin P 《Science (New York, N.Y.)》2007,318(5854):1294-1296
Shape-memory polymers can revert to their original shape when they are reheated. The stress generated by shape recovery is a growing function of the energy absorbed during deformation at a high temperature; thus, high energy to failure is a necessary condition for strong shape-memory materials. We report on the properties of composite nanotube fibers that exhibit this particular feature. We observed that these composites can generate a stress upon shape recovery up to two orders of magnitude greater than that generated by conventional polymers. In addition, the nanoparticles induce a broadening of the glass transition and a temperature memory with a peak of recovery stress at the temperature of their initial deformation. 相似文献