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排序方式: 共有450条查询结果,搜索用时 46 毫秒
131.
Jenkins SJ Ruckerl D Cook PC Jones LH Finkelman FD van Rooijen N MacDonald AS Allen JE 《Science (New York, N.Y.)》2011,332(6035):1284-1288
A defining feature of inflammation is the accumulation of innate immune cells in the tissue that are thought to be recruited from the blood. We reveal that a distinct process exists in which tissue macrophages undergo rapid in situ proliferation in order to increase population density. This inflammatory mechanism occurred during T helper 2 (T(H)2)-related pathologies under the control of the archetypal T(H)2 cytokine interleukin-4 (IL-4) and was a fundamental component of T(H)2 inflammation because exogenous IL-4 was sufficient to drive accumulation of tissue macrophages through self-renewal. Thus, expansion of innate cells necessary for pathogen control or wound repair can occur without recruitment of potentially tissue-destructive inflammatory cells. 相似文献
132.
133.
Yongjie Wang Sarah Shelby Jason Apple Ken Coffey Fred Pohlman Yan Huang 《Animal Science Journal》2021,92(1):e13641
Seventeen crossbred lambs were assigned randomly to low-protein (LP; 8% crude protein [CP]; n = 9) and high-protein (HP; 13% CP; n = 8) diets for 9 weeks. The final body weight, average daily feed intake (ADFI), and average daily gain (ADG) of the HP lambs were significantly higher (P < 0.05) than the LP lambs; however, gain to feed ratio (G:F) for the LP lambs was significantly higher (P < 0.05) than the HP lambs. Hot carcass weight (HCW), adjusted fat thickness, and drip loss of longissimus dorsi (LD) muscle were significantly higher (P < 0.05) for the HP than LP lambs. In contrast, instrumental color values L*, a*, b*, C*, and hue angle (H) of meat from the LP lambs scored significantly higher (P < 0.05) than the HP lambs. The LD muscle from HP lambs had significantly greater CLA of cis-9 trans-11 isomer (P < 0.05) than the LP lambs. The gene expression of metabolism and meat quality-related genes of LP was significantly higher than HP (P < 0.05). These results suggest that a higher dietary CP level promotes growth performance for finishing lambs, whereas lower dietary CP level is beneficial for meat quality, especially when evaluating color characteristics in the final product. 相似文献
134.
Determination of five macrolide antibiotic residues in eggs using liquid chromatography/electrospray ionization tandem mass spectrometry 总被引:1,自引:0,他引:1
A method using liquid chromatography electrospray ionization tandem mass spectrometry (LC/ESI-MS/MS) for the determination of trace levels of five macrolide antibiotics (spiramycin, tilmicosin, oleandomycin, erythromycin, and tylosin) in eggs is presented. Data acquisition under MS/MS was achieved by applying multiple reaction monitoring (MRM) of two or three fragment ion transitions to provide a high degree of sensitivity and specificity for both quantification and confirmation. Matrix-matched standard calibration curves were used to achieve the best accuracy of the method. A fully nested experimental design was used to study the measurement uncertainty arising from intermediate precision and trueness or proportional bias. The overall recoveries, that is, those determined by the nested experiments, of spiramycin, tilmicosin, oleandomycin, erythromycin, and tylosin at fortified levels of 60, 100, 200, and 300 microg/kg were 96.8, 98.2, 98.3, 98.8, and 95.4%, respectively. The LC/ESI-MS/MS method detection limits (S/N > or = 3:1) of five macrolides were <1.0 microg/kg. 相似文献
135.
Bajram Berisha Dieter Schams Fred Sinowatz Daniela Rodler Michael W. Pfaffl 《Reproduction in domestic animals》2020,55(11):1573-1584
The objective of the study was to characterize expression patterns of hypoxia-inducible factor-1alpha (HIF1A), inducible nitric oxide synthase (iNOS) and endothelial (eNOS) isoforms in time-defined follicle classes before and after GnRH application in the cow. Ovaries containing pre-ovulatory follicles or corpora lutea were collected by transvaginal ovariectomy (n = 5 cows/group) as follow: (I) before GnRH administration; (II) 4h after GnRH; (III) 10h after GnRH; (IV) 20h after GnRH; (V) 25h after GnRH; and (VI) 60h after GnRH (early corpus luteum). The mRNA abundance of HIF1A in the follicle group before GnRH was high, followed by a significant down regulation afterwards with a minimum level 25h after GnRH (close to ovulation) and significant increase only after ovulation. The mRNA abundance of iNOS before GnRH was high, decreased significantly during LH surge, with minimum levels afterwards. In contrast, the mRNA of eNOS decreased in the follicle group 20h after GnRH, followed by a rapid and significant upregulation just after ovulation. Immunohistochemically, the granulosa cells of antral follicles and the eosinophils of the theca tissue as well of the early corpus luteum showed a strong staining for HIF1A. The location of the eosinophils could be clearly demonstrated by immunostaining with an eosinophil-specific antibody (EMBP) and transmission electron microscopy. In conclusion, the parallel and acute regulated expression patterns of HIF1A and NOS isoforms, specifically during the interval between the LH surge and ovulation, indicate that these paracrine factors are involved in the local mechanisms, regulating final follicle maturation, ovulation and early luteal angiogenesis. 相似文献
136.
Image-processing software written in C was developed for the COMPAQ 386 computer to detect the hinge in a trimmed oyster hinge-end image. The error rate was 2·5% and the processing speed was 0·7 s per image. Results will be used in an automated oyster shucking machine. 相似文献
137.
138.
Charron CS Allen FL Johnson RD Pantalone VR Sams CE 《Journal of agricultural and food chemistry》2005,53(18):7128-7135
Twelve isoflavones were detected by high-performance liquid chromatography in seeds of 17 soybean [Glycine max (L.) Merrill] cultivars grown at three locations. 6' '-O-Malonyldaidzin and 6' '-O-malonylgenistin together constituted 71-81% of total isoflavones, which ranged in concentration from 2038 to 9514 microg/g and averaged 5644 microg/g across locations and cultivars. The total as well as several individual isoflavones had a moderate negative correlation with oil across locations and cultivars. Six cultivars had a moderate or strong negative correlation of total isoflavones with oil. Five cultivars had a moderate or strong positive correlation of total isoflavones with protein. These results suggest that judicious selection of germplasm for soybean breeding may facilitate development of soybean lines with desirable isoflavone concentrations. 相似文献
139.
Bird use was measured on six salt marshes in New Jersey from 18 April to 18 July 1977 (2 impoundments, 2 ditched marshes and 2 natural salt marshes) in terms of species diversity, numbers of individuals and biomass. Seventy-eight species of birds were recorded in all six marshes although not all species occurred on each marsh. Species diversity was highest on the impoundments, intermediate on the ditched marshes, and lowest in the natural marshes. Species diversity and the number of individuals directly related to the amount of open surface area. The traditional species typical of salt marshes on the East Coast of North America (clapper rails Rallus longirostris, seaside and sharp-tailed sparrows Ammospiza spp.) occurred primarily in the natural salt marshes and were absent from the impoundments. Considerations of species diversity suggest that diversity in salt marsh types is essential to maintaining high species diversity in salt marsh ecosystems. Red-winged blackbirds Agelaius phoeniceus and swallows were the most numerous species, followed by gulls and terns. The impoundments had over five times as many individuals as the natural marshes. Waterfowl, gulls, terns and waders accounted for over 90% of the cumulative biomass in the six marshes, with waterfowl contributing over 50%. This study suggests that conservationists should encourage the maintenance of natural salt marshes because they are necessary habitats for some species even though the diversity and avian biomass is less on natural salt marsh areas than it is on managed areas. 相似文献
140.
Tropical forest trees that produce large fruits and/or large seeds are believed to be dependant on a few and often rare large vertebrates for dispersal. However, little is known about the population dynamics of such trees when they lose their specialised dispersers. This study examines the juvenile spatial distribution of Balanites wilsoniana, Dawe & Spraque, which is believed to be dependant solely on elephants for dispersal, in forests with and without elephants. Using camera traps, elephants were confirmed to be the only frugivores feeding and thus dispersing Balanites wilsoniana fruits. There was a high density of seedlings beneath adult trees in one forest without elephants, which was attributed to low seed and seedling predation in this forest. Nevertheless, it was only in the forest with elephants that juveniles were established away from adult trees. Analysis of the spatial distribution of these juveniles by size revealed that saplings and poles are more likely to be found away from adult trees thus providing evidence that dispersal enhances juvenile survival. This study underlines the importance of seed dispersal for trees that cannot maintain their populations through seedlings germinating and surviving beneath adult conspecifics. The study also demonstrates that loss of vertebrates has ramifications for tree species dynamics above and beyond loss of seed dispersers. 相似文献