3,158 research outputs found

    Presence of Papillomavirus-like DNA sequences in cutaneous fibropapillomas of the goat udder

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    Papillomatous lesions were isolated from the mammary skin of goats and examined for evidence of papillomavirus (PV) infection by various criteria, including gross morphology, histology and DNA hybridization. Although some lesions showed gross papillomatous morphological and histological features similar to those caused by papillomavirus in other species, no viral particles were detected. Reverse slot hybridization revealed cross-hybridization between DNA extracted from goat mammary papillomas and human papillomaviruses (HPV). Southern blot, using ovine papillomavirus (OPV) and bovine papillomavirus type 5 (BPV 5) DNA probes under conditions of reduced stringency (Tm -40 degrees C), detected homologous sequences in 40% of the biopsies. DNA fragments corresponding probably to a monomeric form (7000-8000 bp) of an unknown papillomavirus genome were detected. This study provides evidence for the existence of papillomavirus-like sequences in caprine mammary papillomas and suggests that a papillomavirus is likely to be involved in the development of precancerous lesions of goat mammary skin.[...

    白金微粒/Ru錯合物/高分子薄磨修飾電極之製備及其電催化應用

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    [[abstract]]Membrane-metal modified cells are usually applied to the field of membrane cells, such as fuel cells, light cells… etc. Some hydrogen evolution catalysts, for example Pt metal, are used as the cathodes in these cells. Therefore, in this research, we try to dose a series of Ru complexes into the intervals between the cathode and the thin film electrode to improve the hydrogen evolution efficiency of the membrane-metal modified cells. Ru complex (chosen from Ru(bpy)2phenNH2, Ru(dmb)2 phenNH2, Ru(tmb)2phenNH2, Ru(bpy)2Cl2, Ru(dmb)2Cl2, Ru(tmb)2Cl2) doped Nafion solution was drop-coated onto glassy carbon (GC) electrode and formed a thin film after drying. Then, the GC electrode was immersed into H2PtCl6 solution, and the Pt/Ru complex/polymer modified electrode was obtained by reducing Pt with a DPTB method. Different amount of Pt was electroplated on the GC electrode even at the same conditions (the same potential, the same time interval) when different consistency or kinds of Ru complexes were used, suggesting the influence of the ligands on the red-ox property of Ru complexes. The effective surface area (estimated by CV method) of Pt in the modified electrode is also varied with different species of Ru complexes, which in turn affect on the efficiency of hydrogen evolution. Furthermore, from the information obtained by SEM and EDS, the alignment and the density of Pt particles growing on the GC electrode are figured out. From the fluorescence lifetime and luminescence spectra, a good electron-transfer is considered to have occurred between D series Ru complexes and Pt modified electrode that explained why a high hydrogen evolution efficiency has been obtained. The modified electrodes are still stable one month after fabricated and their hydrogen evolution efficiency was as good as a newly prepared one.
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