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排序方式: 共有183条查询结果,搜索用时 15 毫秒
31.
Self-oriented regular arrays of carbon nanotubes and their field emission properties 总被引:4,自引:0,他引:4
S Fan MG Chapline NR Franklin TW Tombler AM Cassell H Dai 《Science (New York, N.Y.)》1999,283(5401):512-514
The synthesis of massive arrays of monodispersed carbon nanotubes that are self-oriented on patterned porous silicon and plain silicon substrates is reported. The approach involves chemical vapor deposition, catalytic particle size control by substrate design, nanotube positioning by patterning, and nanotube self-assembly for orientation. The mechanisms of nanotube growth and self-orientation are elucidated. The well-ordered nanotubes can be used as electron field emission arrays. Scaling up of the synthesis process should be entirely compatible with the existing semiconductor processes, and should allow the development of nanotube devices integrated into silicon technology. 相似文献
32.
Marisa N. C. Litz Jessica A. Miller Richard D. Brodeur Elizabeth A. Daly Laurie A. Weitkamp Adam G. Hansen Andrew M. Claiborne 《Fisheries Oceanography》2019,28(3):273-290
Variation in prey quantity and quality can influence growth and survival of marine predators, including anadromous fish that migrate from freshwater systems. The objective of this study was to examine the energy dynamics of subyearling Chinook salmon (Oncorhynchus tshawytscha) following freshwater emigration. To address this objective, a population of Chinook salmon and their marine prey were repeatedly sampled from June to September over 2 years in coastal waters off Oregon and Washington. Subyearlings from the same population were also reared under laboratory conditions. Using a bioenergetics model evaluated in the laboratory, we found that growth rate variability in the field was associated more with differences in northern anchovy (Engraulis mordax) consumption and less with variation in diet energy density or ocean temperature. Highest growth rates (2.43–3.22% body weight/day) occurred in months when anchovy biomass peaked, and the timing of peak anchovy biomass varied by year. Our results support a general pattern among subyearling Chinook salmon occurring from Alaska to California that feeding rates contribute most to growth rate variability during early marine residence, although dominant prey types can differ seasonally, annually, or by ecosystem. In the northern California Current, faster growth appears to be associated with the availability of age‐0 anchovy. Identifying factors that influence the seasonal development of the prey field and regulate prey quantity and quality will improve understanding of salmon growth and survival during early marine residence. 相似文献
33.
Composting to sanitize plant‐based waste infected with organisms of plant health importance
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G. Kerins J. Blackburn T. Nixon M. Daly C. Conyers S. Pietravalle R. Noble C. M. Henry 《Plant pathology》2018,67(2):411-417
The potential for using the composting process to sanitize plant waste infected with one of three plant pathogens was investigated using bench‐scale composting equipment. Two of these pathogens, the potato wart disease fungus Synchytrium endobioticum and Potato spindle tuber viroid (PSTVd) are currently subject to European quarantine regulations. The third, Polymyxa betae, a parasite of sugar beet, is regulated in some European countries when in association with Beet necrotic yellow vein virus (BNYVV), the causal organism of rhizomania disease of sugar beet. Survival of test organisms following various combinations of compost temperature, exposure time and moisture was determined using RNA‐based detection methodology and/or plant‐based bioassays. Mathematically definable relationships between compost treatment (temperature/time) and organism viability were identified for P. betae and S. endobioticum; these give some indication of the practicality of using composting for dealing with infected wastes. However, for PSTVd, the considerable variability in measured susceptibility of the viroid to the composting process meant that no such definable relationship could be determined and further work would be needed to extrapolate to practical situations. 相似文献
34.
Rafael Cuevas‐Uribe Edward J Chesney Jonathan Daly Terrence R Tiersch 《Aquaculture Research》2015,46(7):1770-1784
Our goal was to develop a standardized approach for sperm vitrification of marine fish that can be applied generally in aquatic species. The objectives were to: (i) estimate acute toxicity of cryoprotectants over a range of concentrations; (ii) evaluate the properties of vitrification solutions (VS); (iii) evaluate different thawing solutions and (iv) evaluate sperm quality after thawing by examination of motility and membrane integrity. Sperm were collected from red snapper (Lutjanus campechanus), spotted seatrout (Cynoscion nebulosus) and red drum (Sciaenops ocellatus). A total of 29 combinations of cryoprotectants were evaluated for toxicity and glass formation. Samples were loaded onto 10‐μL polystyrene loops and plunged into liquid nitrogen. There was a significant difference (P < 0.05) in post‐thaw motility among VS and among species when using the same VS. The sperm in VS of 15% DMSO + 15% ethylene glycol + 10% glycerol + 1% X‐1000? + 1% Z‐1000? had an average post‐thaw motility of 58% and membrane integrity of 19% for spotted seatrout, 38% and 9% for red snapper, and 30% and 19% for red drum. Adaptations by marine fish to higher osmotic pressures could explain the survival in the high cryoprotectant concentrations. Vitrification offers an alternative to conventional cryopreservation. 相似文献
35.
NR Salvetti C Baravalle GA Mira EJ Gimeno BE Dallard F Rey HH Ortega 《Reproduction in domestic animals》2009,44(5):805-814
The purpose of this study was to estimate the expression and relative amounts of estrogen (ER) and progesterone receptors (PR) and their isoforms as well as heat shock protein 70 (HSP70) in ovaries of rats with induced cystic ovarian disease (COD). Primary, secondary, tertiary, atretic and cystic follicles were evaluated by immunohistochemistry and total ovarian proteins were analyzed by Western blot. In the granulosa layer, growing and cystic follicles in the treated group have a higher expression of ERα than growing follicles of control individuals. In the theca interna layer, tertiary follicles presented a significantly higher expression of ERα in the treated group. An increase in total ERα protein was detected in the treated group. Granulosa cells of all growing, atretic and cystic follicles show a lower expression of ERβ in animals with COD, and the total protein expression of ERβ was lower in this group. The expression of PR was lower in the granulosa cell layer of tertiary and cystic follicles in treated animals, and theca interna layer had less intense immunostaining in this group. Although there were no differences in the expression of PR-B by Western blotting, the expression of PR-A was higher and the expression of PR-C was smaller in the treated group. An intense HSP70 immunostaining was observed in the cells of cystic follicles. By Western blotting, higher protein expression of HSP70 was detected in the ovarian samples of the control group than those of the treated ones. Ovaries of animals with COD exhibited an altered steroid receptor expression and subtype balance as compared with control animals, and an increase in HSP70 immunoexpression. 相似文献
36.
Equine amnionitis and fetal loss: The case definition for an unrecognised cause of abortion in mares
KH Todhunter NR Perkins RM Wylie C Chicken AJ Blishen DJ Racklyeft G Muscatello MC Wilson PL Adams JR Gilkerson WL Bryden AP Begg 《Australian veterinary journal》2009,87(1-2):35-38
A series of abortions occurred in mares in New South Wales during 2004 that involved similar and unusual findings on post mortem examination of aborted fetuses and fetal membranes. The term Equine Amnionitis and Fetal Loss (EAFL) was developed to describe the condition. This form of abortion had not been previously recognised in Australia. The pathology alone is not specific for EAFL and diagnosis requires demonstration of a combination of certain pathological and bacteriological features. The purpose of this paper is to describe patterns considered consistent with EAFL cases as a working case definition for use by veterinarians and veterinary pathologists in identifying future cases of EAFL. More detailed papers are in preparation to fully describe the epidemiological, histopathological, and microbiological aspects of EAFL. 相似文献
37.
Trevor Daly Marvin A. Jiwan Nora M. O’Brien S. Aisling Aherne 《Plant foods for human nutrition (Dordrecht, Netherlands)》2010,65(2):164-169
Herbs are a rich source of bioactive phytochemicals such as carotenoids, which are known to exert various positive biological
effects. However, there is very limited information in the literature regarding the content and bioavailability of carotenoids
from commonly consumed herbs. Therefore, the objectives of the present study were first, to determine the carotenoid content
of eight herbs namely basil (Ocimum basilicum), coriander (Coriandrum sativum), dill (Anethum graveolens), mint (Metha L.),
parsley (Petroselinum crispum), rosemary (Rosmarinus officinalis), sage (Salvia officinalis), and tarragon (Artemisia dracunculus
L.); and second, to assess carotenoid bioaccessibility from these herbs using a simulated human in vitro digestion model.
Carotenoid bioaccessibility is defined as the amount of carotenoids transferred to micelles after digestion when compared
with the original amount present in the food. The content of individual carotenoids varied significantly among the herbs tested.
Carotenoid bioaccessibility varied from 0 to 42.8%. Basil and coriander, and their respective micelles, contained the highest
levels of β-carotene, β-cryptoxanthin, and lutein + zeaxanthin. Our findings show that herbs are rich sources of carotenoids
and that these foods can significantly contribute to the intake of bioaccessible carotenoids. 相似文献
38.
VC McIver AS Tsang NE Symonds NR Perkins E Uquillas CM Dart LB Jeffcott AJ Dart 《Australian veterinary journal》2020,98(6):250-255
39.
40.
Concussive methods of pre-slaughter stunning in sheep: effects of captive bolt stunning in the poll position on brain function 总被引:1,自引:0,他引:1
The effectiveness of captive bolt stunning in the poll position was evaluated in eight anaesthetised sheep. Brain function following shooting was assessed using cortical visual evoked responses (VERs). Immediately following shooting, VERs were abolished in all sheep. However, in five of the sheep, VERs gradually recovered; responses became evident in these animals in a mean (+/- SE) time of 50 +/- 16.7 seconds. These results suggest that captive bolt shooting in the poll position can be associated with rapid recovery of brain function. Because such recovery could be associated with return of sensibility, shooting in the poll position should only be used when essential (ie, in horned animals) and then always followed promptly by sticking. 相似文献