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排序方式: 共有149条查询结果,搜索用时 62 毫秒
91.
Chris W. Rogers Victoria Walsh Erica K. Gee Elwyn C. Firth 《Journal of Veterinary Behavior: Clinical Applications and Research》2012,7(1):49-54
The data for this study were collected from 7 mares (10 ± 1.6 years old) when their foals were 4-, 15-, 30-, 45-, or 60-days-old. On each occasion, the foals were anesthetized and placed out of sight of the mare and the mares’ behavior, heart rate, and cortisol response to foal separation in either the presence of a foal phantom, a square shape, or no visual stimuli were measured. In the presence of the foal phantom, anxious (P = 0.119) and agitated (P = 0.524) mare behavior was not significantly different from baseline values. The mares had significantly elevated behavior scores for 5 out of 6 criteria when the square phantom was presented and were significantly more active (higher scores for fidgety and active criteria) when no visual stimuli (control) were provided. Based on the data presented in this study, the use of a phantom image of a foal with neutral ear and tail position may be an effective nonchemical method of calming mares during separation from their foal. 相似文献
92.
Enzyme-linked immunosorbent assay for the pyrethroid permethrin 总被引:8,自引:0,他引:8
Shan G Leeman WR Stoutamire DW Gee SJ Chang DP Hammock BD 《Journal of agricultural and food chemistry》2000,48(9):4032-4040
Permethrin is a predominant pyrethroid widely used in agriculture and public health. A competitive enzyme-linked immunosorbent assay (ELISA) for the detection of permethrin was developed. Two haptens, the trans- and cis-isomers of 3-(4-aminophenoxy)benzyl-3-(2, 2-dichloroethenyl)-2,2-dimethylcyclopropanecarboxylate, were synthesized and conjugated with thyroglobulin as immunogens. Four antisera were generated and screened against six different coating antigens. The resulting ELISA has an I(50) value of 2.50 microg/L and relatively low cross-reactivities with other major pyrethroids, such as esfenvalerate, cypermethrin, deltamethrin, and cyfluthrin. Methanol was found to be the best solvent for this ELISA, with optimal sensitivity observed at a concentration of 40% (v/v). The assay parameters are unchanged at pH values between 5.0 and 8.0, whereas higher ionic strengths (>0.2 M PBS) strongly suppress the absorbances. River water samples fortified with permethrin were analyzed according to this method and validated by GC-MS. Good recoveries and correlation with spike levels were observed, suggesting this immunoassay is valuable for environmental monitoring and toxicological studies at parts per trillion levels of permethrin. 相似文献
93.
Robust and sensitive monoclonal enzyme-linked immunosorbent assay for the herbicide molinate 总被引:2,自引:0,他引:2
Rufo C Hammock BD Gee SJ Last JA González-Sapienza G 《Journal of agricultural and food chemistry》2004,52(2):182-187
This paper reports on the generation of monoclonal antibodies and the development of a new enzyme-linked immunosorbent assay (ELISA) for the detection of molinate (S-ethyl hexahydroazepine-1-carbothioate). Hybridoma cells were generated using spleen and lymph node cells from a mouse immunized with S-2-carboxyethyl hexahydroazepine-1-carbothioate conjugated to keyhole limpet hemocyanin. After screening with a competitive ELISA, two monoclonal antibodies, mAbs 16C11 and 14D7, with IC(50) values of 82 +/- 2 and 173 +/- 8 ng/mL, respectively, were selected. MAb 16C11 can detect molinate concentrations of 1 ng/mL with no cross-reactivity to any other thiocarbamate pesticides; however, it was susceptible to the presence of organic solvents and to variation in buffer ionic strength. MAb 14D7 tolerated concentrations up to 5% of propylene glycol and 12.5% of acetonitrile in the assay buffer. The sensitivity of mAb 14D7 was further improved by decreasing the amount of coating antigen in the ELISA; the final inhibition assay showed an IC(50) of 69.2 +/- 1.4 ng/mL. In summary, mAb14D7 provided a more sensitive and robust assay, as compared with previous polyclonal antibody-based assays, with the additional advantage of being based upon a consistent and unlimited source of a defined reagent. 相似文献
94.
The cape mendocino, california, earthquakes of april 1992: subduction at the triple junction 总被引:1,自引:0,他引:1
Oppenheimer D Eaton J Jayko A Lisowski M Marshall G Murray M Simpson R Stein R Beroza G Magee M Carver G Dengler L McPherson R Gee L Romanowicz B Gonzalez F Li WH Satake K Somerville P Valentine D 《Science (New York, N.Y.)》1993,261(5120):433-438
The 25 April 1992 magnitude 7.1 Cape Mendocino thrust earthquake demonstrated that the North America-Gorda plate boundary is seismogenic and illustrated hazards that could result from much larger earthquakes forecast for the Cascadia region. The shock occurred just north of the Mendocino Triple Junction and caused strong ground motion and moderate damage in the immediate area. Rupture initiated onshore at a depth of 10.5 kilometers and propagated up-dip and seaward. Slip on steep faults in the Gorda plate generated two magnitude 6.6 aftershocks on 26 April. The main shock did not produce surface rupture on land but caused coastal uplift and a tsunami. The emerging picture of seismicity and faulting at the triple junction suggests that the region is likely to continue experiencing significant seismicity. 相似文献
95.
This overview of sensitive surface waters in the United Kingdom has focused on palaeolimnological studies, the estimation of acidification values according the Henriksen, and correlation with non-marine sulphate values of available chemical data and trends in salmonid populations. The palaeolimnological studies of lakes with unafforested catchments in Galloway led to the conclusion that changes in water acidity, since the 1800's, have been caused by acid deposition. Significant differences in stream chemistry between mature conifer forests and adjacent moorland catchments, in both Wales and Scotland, suggest that afforestation as well as acid deposition have contributed to the decline and, in some areas, the elimination of the salmonid population. 相似文献
96.
Heo HJ Kim DO Shin SC Kim MJ Kim BG Shin DH 《Journal of agricultural and food chemistry》2004,52(6):1520-1525
Amyloid beta protein (Abeta)-induced free radical-mediated neurotoxicity is known as a leading hypothesis for a cause of Alzheimer's disease. Abeta increased free radical production and lipid peroxidation in PC12 nerve cells, resulting in apoptosis and cell death. The protective effect of naringenin, a major flavanone constituent isolated from Citrus junos, against Abeta-induced neurotoxicity was investigated using PC12 cells. Pretreatment with isolated naringenin and vitamin C prevented the generation of the Abeta-induced reactive oxygen species. Naringenin resulted in the decrease of Abeta toxicity in a manner of concentration dependence, which was assessed by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. However, treatment with these antioxidants inhibited the Abeta-induced neurotoxic effect. The antiamnestic activity of naringenin in vivo was also evaluated using ICR mice with amnesia induced by scopolamine (1 mg/kg body weight). Naringenin, when administered to ICR mice at 4.5 mg/kg body weight, significantly ameliorated scopolamine-induced amnesia as measured in the passive avoidance test. Therefore, these results indicate that micromolecular Abeta-induced in vitro oxidative cell stress is reduced by naringenin and naringenin may be a useful chemopreventive agent against a neurodegenerative disease such as Alzheimer's disease. 相似文献
97.
Asbestos: scientific developments and implications for public policy 总被引:41,自引:0,他引:41
Asbestos is a commercial term for a group of fibrous minerals often associated with the development of pulmonary interstitial fibrosis (asbestosis), lung cancer, and malignant mesothelioma in occupationally exposed individuals. The pathogenicity of different forms of asbestos varies--long, thin amphibole fibers are most pathogenic, particularly in the induction of mesothelioma. Available data do not support the concept that low-level exposure to asbestos is a health hazard in buildings and schools. The concentration of asbestos fibers in air, type of asbestos, and size of fibers must be considered in evaluation of potential health risks. 相似文献
98.
Driejana D. W. Raper D. S. Lee R. D. Kingdon I. L. Gee 《Water, air, and soil pollution》2001,130(1-4):1625-1630
Fine spatial-scale measurements of acidic deposition have been made over two time frames: 1987/1988 and 1999/2000. Over this period, dramatic reductions in precursor emissions have occurred. The two sets of data are compared in order to quantify deposition reductions. Orographic enhancement of wet deposition from the seeder-feeder mechanism is important in the UK at high-elevation sites such as these and the measurements were corrected for this process using a standard methodology. The data were also modelled using a simple long-term Lagrangian acid deposition model and comparisons made with both sets of observations at a resolution of 5 km_5 km. Future scenarios (2010) of emissions were modelled to examine the impact of UK and other European sources in order to determine optimal protection of ecosystems in this region. 相似文献
99.
Simon Potter Sandra Reath Ashif Hussein Wai Gee Val Lawrence James Drummond 《Wood Science and Technology》2003,37(3-4):321-329
We have found that kraft pulp handsheets, made from a number of hybrid poplar (Populus trichocarpa × Populus deltoides) clones, contain unusual surface deformations caused by vessel element mineral blockages. The blockages were composed mainly of calcium salt deposits that survived chemical pulping and beating processes. Our findings confirm that a natural process of accumulation of calcium salts occurs in certain poplar species. In this article, we describe the implications for the multi-use implementation of these poplars in short-rotation, intensive-culture plantations. 相似文献
100.
IntroductionIn1980,ThomasLovejoyoftheWorldWildlifeFundStatedthatreduCtioninthebiologicaldiversityoftheplanetisthemoStbasicissueofourtimeandthatslowingthisprocessof"bioticimpoverishment"isagreatchallengetotheingenuityofbiologiSts.Extinctionofaspeciesrepresentsthelossofaresourcethathasevolvedthroughthousands,perhapsmillions,ofyearsofmutationandnaturalseleCtion(Durrant,1990).Asthenumberofbieds'speciesthreatenedwitheXtinCtionincrease,agriculturistsandconservationistshavejoinedforceinaneffortt… 相似文献