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排序方式: 共有288条查询结果,搜索用时 267 毫秒
281.
Iacome SC Jácome Francisca GC Sousa Candice MG De Leon Denis A Spricigo Mauro MS Saraiva Patricia EN Givisiez Wondwossen A Gebreyes Rafael FC Vieira Celso JB Oliveira 《Veterinary research》2014,45(1)
This investigation reported for the first time the occurrence of intramammary infections caused by Staphylococcus in primiparous replacement goats before parturition and the persistence of clinical Staphylococcus aureus infection during the lactation period. Subclinical infections, mainly caused by coagulase negative staphylococci (CoNS), did not persist during lactation. Genotyping analysis indicated that environment seems to play a moderate role as source of intramammary infections to goats before parturition, but causative agents of mastitis in lactating animals are not genotypically related to environmental staphylococci. The occurrence and persistence of intramammary infections in replacement goats demonstrate the need to consider those animals as potential sources of infections in dairy goat herds. 相似文献
282.
Relatively unoxidized black uranium ores from sandstone deposits in the western United States show deviations in the uranium-235 to uranium-234 ratio throughout a range from 40 percent excess uranium-234 to 40 percent deficient uranium-234 with respect to a reference uranium-235 to uranium-234 ratio. The deficient uranium-234 is leached preferentially to uranium-238 and the excess uranium-234 is believed to result from deposition of uranium-234 enriched in solutions from leached deposits. 相似文献
283.
284.
Garner EC Bernard R Wang W Zhuang X Rudner DZ Mitchison T 《Science (New York, N.Y.)》2011,333(6039):222-225
Rod-shaped bacteria elongate by the action of cell wall synthesis complexes linked to underlying dynamic MreB filaments. To understand how the movements of these filaments relate to cell wall synthesis, we characterized the dynamics of MreB and the cell wall elongation machinery using high-precision particle tracking in Bacillus subtilis. We found that MreB and the elongation machinery moved circumferentially around the cell, perpendicular to its length, with nearby synthesis complexes and MreB filaments moving independently in both directions. Inhibition of cell wall synthesis by various methods blocked the movement of MreB. Thus, bacteria elongate by the uncoordinated, circumferential movements of synthetic complexes that insert radial hoops of new peptidoglycan during their transit, possibly driving the motion of the underlying MreB filaments. 相似文献
285.
Carles Juan-Sallés Rui Patrício Joseba Garrido Michael M. Garner 《Journal of Exotic Pet Medicine》2009,18(4):306-310
Although mycobacteria have been isolated from rodents, overt mycobacteriosis is rare in any rodent species. A pet adult male Richardson's ground squirrel (Spermophilus richardsonii) died after a short course of alopecia, anorexia, and weight loss. Necropsy and subsequent histopathological examination of tissue samples revealed disseminated granulomatous inflammation involving the lungs, lymph nodes, liver, intestine, adrenal gland, spleen, pleura, and peritoneum. Ziehl-Neelsen stain revealed high numbers of acid-fast bacilli within the cytoplasm of macrophages and multinucleated giant cells. Polymerase chain reaction performed on paraffin-embedded tissues was positive for Mycobacterium avium subsp. avium and negative for M. bovis-tuberculosis complex. Three females housed with this squirrel remained clinically healthy, and mycobacterial cultures of pooled feces from these animals were negative. To the authors' knowledge, this is the second report of disseminated mycobacteriosis in squirrels involving M. avium subsp. avium, with both cases described recently in the Iberian Peninsula. 相似文献
286.
P. Garner 《Ecology of Freshwater Fish》1999,8(1):55-58
Abstract– The ability of chub, dace and roach to resist displacement in a laboratory channel was not only controlled by species-specific swimming ability, but also by the fishes'ability to locate areas of reduced velocity. Dace were better able to withstand high velocities than roach. Chub were better at locating slow flowing patches than either roach or dace throughout their early development. Only chub larvae shifted towards slower flowing patches as velocity increased. All juveniles shifted to slower flowing patches at high velocities. 相似文献
287.
RJ Jackman ST Brittain A Adams MG Prentiss GM Whitesides 《Science (New York, N.Y.)》1998,280(5372):2089-2091
Two concepts for use in the fabrication of three-dimensional (3D) microstructures with complex topologies are described. Both routes begin with a two-dimensional (2D) pattern and transform it into a 3D microstructure. The concepts are illustrated by use of soft lithographic techniques to transfer 2D patterns to cylindrical (pseudo-3D) substrates. Subsequent steps-application of uniaxial strain, connection of patterns on intersecting surfaces-transform these patterns into free-standing, 3D, noncylindrically symmetrical microstructures. Microelectrodeposition provides an additive method that strengthens thin metal designs produced by patterning, welds nonconnected structures, and enables the high-strain deformations required in one method to be carried out successfully. 相似文献
288.