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排序方式: 共有1426条查询结果,搜索用时 15 毫秒
911.
Meech KJ Ageorges N A'Hearn MF Arpigny C Ates A Aycock J Bagnulo S Bailey J Barber R Barrera L Barrena R Bauer JM Belton MJ Bensch F Bhattacharya B Biver N Blake G Bockelée-Morvan D Boehnhardt H Bonev BP Bonev T Buie MW Burton MG Butner HM Cabanac R Campbell R Campins H Capria MT Carroll T Chaffee F Charnley SB Cleis R Coates A Cochran A Colom P Conrad A Coulson IM Crovisier J deBuizer J Dekany R de Léon J Dello Russo N Delsanti A DiSanti M Drummond J Dundon L Etzel PB Farnham TL Feldman P 《Science (New York, N.Y.)》2005,310(5746):265-269
On 4 July 2005, many observatories around the world and in space observed the collision of Deep Impact with comet 9P/Tempel 1 or its aftermath. This was an unprecedented coordinated observational campaign. These data show that (i) there was new material after impact that was compositionally different from that seen before impact; (ii) the ratio of dust mass to gas mass in the ejecta was much larger than before impact; (iii) the new activity did not last more than a few days, and by 9 July the comet's behavior was indistinguishable from its pre-impact behavior; and (iv) there were interesting transient phenomena that may be correlated with cratering physics. 相似文献
912.
Nicotine is chemotactic for neutrophils and enhances neutrophil responsiveness to chemotactic peptides 总被引:7,自引:0,他引:7
N Totti K T McCusker E J Campbell G L Griffin R M Senior 《Science (New York, N.Y.)》1984,223(4632):169-171
Neutrophils contribute to chronic bronchitis and pulmonary emphysema associated with cigarette smoking. Nicotine was found to be chemotactic for human neutrophils but not monocytes, with a peak activity at approximately 31 micromolar. In lower concentrations (comparable to those in smokers' plasma), nicotine enhanced the response of neutrophils to two chemotactic peptides. In contrast to most other chemoattractants for neutrophils, however, nicotine did not affect degranulation or superoxide production. Nicotine thus may promote inflammation and consequent lung injury in smokers. 相似文献
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914.
Lysa P Posner Christopher L Mariani Cliff Swanson Makoto Asakawa Nigel Campbell Adam S King 《Veterinary anaesthesia and analgesia》2014,41(2):137-144
ObjectiveTo evaluate and compare perioperative morbidity and mortality in dogs undergoing cervical and thoracolumbar spinal surgery.Study designProspective case series.Animals157 dogs undergoing cervical or thoracolumbar spinal surgery.MethodsData were collected sequentially on canine cases presented from the Neurology Section of the North Carolina State University Veterinary Teaching Hospital for anesthesia and surgery for cervical spinal cord disease. Simultaneously, data were collected on all thoracolumbar spinal surgery cases during the same time period. Data included signalment, drugs administered, surgical approach, disease process, cardiac arrhythmias during anesthesia, and outcome.ResultsData were collected from 164 surgical events in 157 dogs. There were 52 cervical approaches; four dorsal and 48 ventral. All thoracolumbar surgeries were approached dorsolaterally. Four dogs 4/52 (7.6%) undergoing a cervical approach did not survive to discharge. Two dogs (2/8; 25%) underwent atlanto-axial (AA) stabilization and suffered cardiovascular arrest and two dogs (2/38; 5.2%) undergoing cervical ventral slot procedures were euthanized following anesthesia and surgery due to signs of aspiration pneumonia. All dogs undergoing thoracolumbar surgery survived until discharge (112/112). Mortality in dogs undergoing cervical spinal surgery was greater compared with dogs undergoing thoracolumbar spinal surgery (p = 0.009), however, in dogs undergoing decompressive disc surgery, intraoperative death rates were not different between dogs undergoing a cervical compared with thoracolumbar approaches (p = 0.32) nor was there a significant difference in overall mortality (p = 0.07).Conclusion and clinical relevanceOverall, dogs undergoing cervical spinal surgery were less likely to survive until discharge compared with dogs undergoing thoracolumbar spinal surgery. Mortality in dogs undergoing cervical intervertebral disc decompression surgery was no different than for dogs undergoing thoracolumbar intervertebral disc decompression surgery. However, dogs undergoing cervical intervertebral disc decompression surgery should be considered at risk for aspiration pneumonia. 相似文献
915.
Kabita Kharel Frank H. Arthur Kun Yan Zhu James F. Campbell Bhadriraju Subramanyam 《Journal of pest science》2014,87(2):295-300
Accumulated grain dust and flour residues in flour mills can potentially decrease the efficacy of contact surface treatments and aerosol insecticides used for control of adult and immature stages of stored product insects. A study was conducted to evaluate the effects of flour residues on the efficacy of piperonyl butoxide-synergized pyrethrin aerosol against different life stages of the confused flour beetle, Tribolium confusum Jacquelin du Val. Twenty individual adults, pupae, or larvae of T. confusum, confined in Petri dishes containing 0, 0.1, 1, 5, or 10 g of wheat flour, were exposed separately inside an empty shed to the label rate of the aerosol. The formulation contained 1 % active ingredient pyrethrin and the label application rate was 1.04 ml/m3. After 2 h of exposure, all dishes were removed from the shed and placed in an incubator set at 27 °C and 60 % RH. Mortality of T. confusum adults decreased with increasing amount of flour. Recovery of moribund adults 15 days after exposure was greater in the 5 and 10 g flour dishes (15 and 46 %) compared to the 0.1 or 1 g flour dishes (0.7 and 5 %). As the flour amounts increased, more larvae and pupae were able to emerge as adults. Results show accumulated flour residues during aerosol application can compromise aerosol efficacy, and also suggest the flour impaired penetration ability of the aerosol. These results also emphasize the importance of sanitation and cleaning to remove spillage and extraneous material prior to an aerosol application. 相似文献
916.
917.
918.
919.
Karen E. Shearer Michael J. Harte Davor Ojkic Josepha DeLay Douglas Campbell 《The Canadian veterinary journal. La revue veterinaire canadienne》2014,55(3):240-248
A total of 460 kidney samples from wildlife (beavers, coyotes, deer, foxes, opossums, otters, raccoons, skunks) were obtained from road-kill and hunter/trapper donations in Ontario between January 2010 and November 2012. The objectives of the study were to detect Leptospira spp. by immunohistochemistry and polymerase chain reaction (PCR), to map presence of leptospires in wildlife relative to livestock and human populations, and to characterize positive samples by sequencing and comparison to leptospires known to affect domestic animals and humans. The proportion of samples that tested positive ranged from 0% to 42%, with the highest rates in skunks and raccoons. Leptospira spp. were present in kidneys of wildlife across Ontario, particularly in areas of high human density, and areas in which livestock populations are abundant. The PCR was too weak in most samples to permit genotyping and examination of the relationship between the leptospires found in this study and those affecting domestic animals and humans. 相似文献
920.
C. D. Campbell L. A. Mackie-Dawson E. J. Reid S. M. Pratt E. I. Duff S. T. Buckland 《Agroforestry Systems》1994,26(2):75-87
The use of a simple counting method using a borescope and minirhizotron system to study the interaction of roots of wild cherry trees (Prunus avium L) and pasture in an upland silvopastoral system is described. Operator variation was greatest when distinguishing different tree root categories (e.g. white, brown, woody) but was not significant in relation to total tree or grass root counts or species differences. Analysis of covariance was used to take these differences into account in a field trial using several operators. The seasonal patterns of tree and pasture root growth were different. Tree roots peaked in May before maximal shoot growth. The peak in pasture roots occurred two weeks earlier. Tree height growth was increased by the use of herbicides to control grass growth but this effect was only apparent during August when the soil was dry and when pasture root counts were reduced. 相似文献