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A full ophthalmic examination was performed on 40 Siberian husky dogs using direct and indirect ophthalmoscopy, gonloscopy and nasolacrimal cannulation. Eight (20%) of the dogs were found to have distichia, 10 (25%) had excessive medial caruncular hairs, 8 (20%) had absence, displacement, or narrowing of the nasolacrimal puncta, 2 (5%) had bilateral corneal crystalline opacities, and 2 (5%) had unilateral areas of lateral corneal lipidosis. Fifty percent of the dogs had some abnormality of the iridocorneal (drainage) angle. However, in only one of these was the deformity severe enough to require glaucoma prophylaxis. An association between blue iris colour and malformation of the iridocorneal angle was noted. 相似文献
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RP Andres T Bein M Dorogi S Feng JI Henderson CP Kubiak W Mahoney RG Osifchin R Reifenberger 《Science (New York, N.Y.)》1996,272(5266):1323-1325
Double-ended aryl dithiols [alpha,alpha'-xylyldithiol (XYL) and 4,4'-biphenyldithiol] formed self-assembled monolayers (SAMs) on gold(111) substrates and were used to tether nanometer-sized gold clusters deposited from a cluster beam. An ultrahigh-vacuum scanning tunneling microscope was used to image these nanostructures and to measure their current-voltage characteristics as a function of the separation between the probe tip and the metal cluster. At room temperature, when the tip was positioned over a cluster bonded to the XYL SAM, the current-voltage data showed "Coulomb staircase" behavior. These data are in good agreement with semiclassical predictions for correlated single-electron tunneling and permit estimation of the electrical resistance of a single XYL molecule (approximately18 ± 12 megohms). 相似文献
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It was possible to produce an active Arthus reaction in chicken skin which resulted in gross and microscopic lesions. Histologically, the reaction was predominantly thrombotic in nature and restricted to the upper dermis. The thrombi appeared to develop as a consequence of immune complex deposition with adherence and aggregation of thrombocytes at the vascular endothelium. Thrombosis induced widespread necrosis and haemorrhage and vasculitis occurred in the lower dermis. Up to four hours after inoculation, the cell population comprised an infiltration of heterophils, monocytes and basophils, suggesting an immediate hypersensitivity reaction. This was followed by an Arthus type reaction for four to 12 hours involving both heterophils and monocytes. A characteristic feature was the development of early perivascular lymphoid foci. After 12 hours the reaction resembled a delayed hypersensitivity. The use of colloidal carbon suggested that whereas phagocytic activity of the heterophils and basophils appeared sensitisation dependent, that of thrombocytes and monocytes was independent of it. The findings indicate that in the Arthus reaction in the chicken the thrombocyte appears to be the principal cell producing tissue damage by thrombosis. A comparison was made with the active Arthus reaction in the rabbit. 相似文献
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Summary From a total of 32 poultry flocks 1,176 serum samples were screened by the agar gel precipitation test and 314 (26·7%) were
positive for antibodies to infectious bursal disease virus (IBDV). Prevalence of infection on the farms ranged from 8·88 to
53·84 per cent. The prevalence was highest (61·82%) in chickens between 7 and 11 weeks old and lowest (3·92%) in those above
22 weeks of age. In commercial broilers and layers 51·61 and 17·78% respectively were seropositive reactors. The high prevalence
of subclinical IBD and its economic significance are discussed.
Resumen Un mil ciento setenta y seis sueros (1.176), fueron procesados mediante la prueba de precipitación en agar gel y 314 (26·7%) fueron positivos a anticuerpos de bursitis infecciosa (BI). La prevalencia de la infección en granjas avícolas varió entre 8·88 y 53·84 por ciento. La prevalencia fue más alta en pollos entre siete y 11 semanas de edad, siendo baja (3·92%) en aquellos por encima de 22 semanas. En pollos de engorde y ponedoras, los reactores seropositivos fueron 51·61 y 17·78%, respectivamente. Se discute la alta prevalencia de la BI y su significado económico.
Résumé Sur un total de 32 élevages de volailles, 1176 échantillons de sérums ont été examinés au moyen du test de précipitation en gélose; 314 (26,7 p. 100) étaient positifs vis-à-vis de la maladie de Gumboro (bursite infectieuse). La prévalence de cette infection en milieu fermier allait de 8,88 à 53,84 p. 100. Elle était plus élevée chez les poulets (61,82 p. 100) agés de 7 à 11 semaines et moins prononcée (3,29 p. 100) chez ceux agés de plus de 22 semaines. Dans les élevages commerciaux et chez les pondeuses 51,61 et 17,78 p. 100, respectivement, ont réagi positivement. Les auteurs discutent de l'importance de la bursite infectieuse subclinique et de sa répercussion économique.相似文献
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W Zhou JM Thomas DS Shephard BFG Johnson D Ozkaya T Maschmeyer RG Bell Q Ge 《Science (New York, N.Y.)》1998,280(5364):705-708
The anionic ruthenium cluster carbonylates [Ru6C(CO)16]2- or [H2Ru10(CO)25]2- interspersed with bis(triphenylphosphino)iminium counterions (PPN+) are incorporated from solution into the pores of MCM-41 mesoporous silica (3 nanometers in diameter), where they form tightly packed arrays. These arrays were shown by high-resolution transmission electron microscopy, Fourier transform optical diffraction, and computer simulations to be well ordered both along and perpendicular to the axis of the cylindrical pores. In their denuded state produced by gentle thermolysis, the cluster carbonylates yield nanoparticles of ruthenium that are less well ordered than their assimilated precursors but show good activity as hydrogenation catalysts for hexene and cyclooctene. In both their as-prepared and denuded states, these encapsulated clusters are likely to exhibit interesting electronic and other properties. 相似文献
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While much is known about the metabolism of exogenous nutrients such as glucose, lactate, pyruvate, amino acids by oocytes and pre-implantation mammalian embryos, the role of endogenous stores, particularly lipid, has been largely overlooked. The presence of lipid within oocytes and early embryos has been long known, and comparisons between species indicate that the amounts and types of lipid present vary considerably. Large amounts of intracellular lipid can compromise the success of cryopreservation and the removal of such lipid has been the subject of considerable effort. In this review, we present evidence that strongly suggests a metabolic role for lipid, specifically with regard to energy provision, in the late-stage oocyte and the pre-implantation embryo. We focus initially on oxygen consumption as a global indicator of metabolic activity, before reviewing different approaches that either have been designed to investigate directly, or have revealed indirectly the role of endogenous lipid in energy generation. These fall under five headings: (i) fatty acid oxidation; (ii) inhibition of triglyceride oxidation; (iii) culture in the absence of exogenous substrates; (iv) cytoplasmic organization; and (v) delipidation. On the basis of the data derived from these studies, we conclude that there is strong evidence for the utilization of endogenous lipid as an energy substrate by oocytes and early embryos. 相似文献