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111.
Federico Vilaplana Grosso Stacy Tinkler Mario Sola Margaret Miller Hock Gan Heng 《Veterinary radiology & ultrasound》2020,61(1):E6-E11
A 2‐year‐old Boer doe was presented with respiratory distress and severe inspiratory dyspnea. Cervical and thoracic radiographs revealed a marked retropharyngeal soft tissue mass effect, several mineralized pharyngeal and retropharyngeal structures, and a pulmonary mass. Computed tomography (CT) revealed a severely enlarged right medial retropharyngeal lymph node, which caused laryngeal compression, leading to upper airway obstruction. Multiple cervical and thoracic lymph nodes, and the pulmonary mass had an irregular layered/laminated pattern of mineralization. Imaging findings were consistent with caseous lymphadenitis, and further confirmed with culture, necropsy, and histopathology. This is the first report of CT appearance of caseous lymphadenitis in a goat. 相似文献
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114.
Palazzo AF Eng CH Schlaepfer DD Marcantonio EE Gundersen GG 《Science (New York, N.Y.)》2004,303(5659):836-839
Microtubule (MT) stabilization is regulated by the small guanosine triphosphate (GTP)-binding protein Rho and its effector, mammalian homolog of Diaphanous (mDia), in migrating cells, but factors responsible for localized stabilization at the leading edge are unknown. We report that integrin-mediated activation of focal adhesion kinase (FAK) at the leading edge is required for MT stabilization by the Rho-mDia signaling pathway in mouse fibroblasts. MT stabilization also involved FAK-regulated localization of a lipid raft marker, ganglioside GM1, to the leading edge. The integrin-FAK signaling pathway may facilitate Rho-mDia signaling through GM1, or through a specialized membrane domain containing GM1, to stabilize MTs in the leading edge of migrating cells. 相似文献
115.
Wachowiak A Yamachika R Khoo KH Wang Y Grobis M Lee DH Louie SG Crommie MF 《Science (New York, N.Y.)》2005,310(5747):468-470
We present a low-temperature scanning tunneling microscopy (STM) study of K(x)C60 monolayers on Au(111) for 3 < or = x < or = 4. The STM spectrum evolves from one that is characteristic of a metal at x = 3 to one that is characteristic of an insulator at x = 4. This electronic transition is accompanied by a dramatic structural rearrangement of the C60 molecules. The Jahn-Teller effect, a charge-induced mechanical deformation of molecular structure, is directly visualized in the K4C60 monolayer at the single-molecule level. These results, along with theoretical analyses, provide strong evidence that the transition from metal to insulator in K(x)C60 monolayers is caused by the Jahn-Teller effect. 相似文献
116.
Phonon density of states of iron up to 153 gigapascals 总被引:4,自引:0,他引:4
Mao HK Xu J Struzhkin VV Shu J Hemley RJ Sturhahn W Hu MY Alp EE Vocadlo L Alfè D Price GD Gillan MJ Schwoerer-Böhning M Häusermann D Eng P Shen G Giefers H Lübbers R Wortmann G 《Science (New York, N.Y.)》2001,292(5518):914-916
We report phonon densities of states (DOS) of iron measured by nuclear resonant inelastic x-ray scattering to 153 gigapascals and calculated from ab initio theory. Qualitatively, they are in agreement, but the theory predicts density at higher energies. From the DOS, we derive elastic and thermodynamic parameters of iron, including shear modulus, compressional and shear velocities, heat capacity, entropy, kinetic energy, zero-point energy, and Debye temperature. In comparison to the compressional and shear velocities from the preliminary reference Earth model (PREM) seismic model, our results suggest that Earth's inner core has a mean atomic number equal to or higher than pure iron, which is consistent with an iron-nickel alloy. 相似文献
117.
Mao WL Mao HK Eng PJ Trainor TP Newville M Kao CC Heinz DL Shu J Meng Y Hemley RJ 《Science (New York, N.Y.)》2003,302(5644):425-427
Compressed under ambient temperature, graphite undergoes a transition at approximately 17 gigapascals. The near K-edge spectroscopy of carbon using synchrotron x-ray inelastic scattering reveals that half of the pi-bonds between graphite layers convert to sigma-bonds, whereas the other half remain as pi-bonds in the high-pressure form. The x-ray diffraction pattern of the high-pressure form is consistent with a distorted graphite structure in which bridging carbon atoms between graphite layers pair and form sigma-bonds, whereas the nonbridging carbon atoms remain unpaired with pi-bonds. The high-pressure form is superhard, capable of indenting cubic-diamond single crystals. 相似文献
118.
赵贵 《河北农业大学学报》1991,14(3):75-77
剪切泄漏的方向应以缝隙中相对静止的断面为参照基准;复合泄漏流量是压剪泄漏和剪切泄漏两种流量的矢量和;而复合泄漏功率损失是压差泄漏和剪切泄漏两种功率损失的代数和。液压元件最佳环形缝隙的优化设计,应以实际机加工精度和元件运行状况为基础,综合设计缝隙的高度、缝隙的长度和油液的粘度等参数。 相似文献
119.
H. Niklas und A. Hock 《Forstwissenschaftliches Centralblatt》1924,46(8):392-394
Ohne Zusammenfassung 相似文献
120.
PREVALENCE AND SIGNIFICANCE OF AN ULTRASONOGRAPHIC COLONIC MUSCULARIS HYPERECHOIC BAND PARALLELING THE SEROSAL LAYER IN DOGS 下载免费PDF全文
Hock Gan Heng Chee Kin Lim Margaret A. Miller Meaghan M. Broman 《Veterinary radiology & ultrasound》2015,56(6):666-669
The muscularis layer of the canine colon has been reported to appear homogeneously hypoechoic on ultrasonography. A hyperechoic band in the muscularis layer paralleling the serosal surface has been observed by authors in routine canine abdominal ultrasound examinations. The purpose of this prospective and retrospective cross‐sectional study was to determine the prevalence of this lesion, characterize its ultrasonographic and postmortem histologic features, and correlate its presence with clinical signs of gastrointestinal disease. In the prospective study, all dogs that underwent routine abdominal ultrasonography by one of two observers during a 4‐week period were included without any exclusion criteria. One observer reviewed ultrasound images and recorded the presence or absence of this lesion and its distribution, e.g. focal (< 2 cm long) or diffuse (> 2 cm long). In the retrospective study, all dogs that had both abdominal ultrasonography and necropsy from January 2011 to December 2013 were included without any exclusion criteria. Histologic examinations were performed by two observers and Masson's trichrome stain was used to identify fibrous collagen. Prevalence for the hyperechoic band was 32% in the prospective and 4.8% in the retrospective sample populations, respectively. The hyperechoic band appeared as diffuse, focal, or a combination of both. Histologic sections were available for six dogs. In a few cases, the lesion corresponded to the presence of fibrous tissue in the myenteric plexus or in the tunica muscularis. None of the dogs had a history of diarrhea. Findings supported the hypothesis that a colonic muscularis hyperechoic band paralleling the serosal layer in dogs could be a normal variant rather than a marker of disease. 相似文献