970 resultados para Orth, Ulrich
Resumo:
Se describe la situación actual de las revistas científicas de las universidades españolas con el propósito de señalar algunas acciones para mejorar su difusión. En primer lugar, se ofrecen diversos datos cuantitativos sobre las revistas científicas universitarias que proceden de directorios de revistas (CINDOC, Ulrich"s y Latindex, fundamentalmente). A continuación, se señalan un conjunto de siete líneas básicas de actuación para mejorar su difusión e impacto: digitalización de contenidos, inclusión en portales, difusión en libre acceso, elaboración de versiones multilingües, comunicación de novedades, medición de la audiencia, e inclusión en bases de datos. Finalmente, se hace referencia a los principales agentes que pueden llevar a cabo este tipo de actuaciones.
Resumo:
The neuropathology of a clinically well-documented case of the neonatal progeroid syndrome Wiedemann-Rautenstrauch is described. The most striking feature was a nearly complete absence of mature myelin in the brain. When immunohistochemistry for myelin basic protein was applied, some subcortical nerve fibres were accompanied by immature myelin sheaths. The neuropathology corresponds exactly to that of Pelizaeus-Merzbacher disease (Seitelberger type). Furthermore, this morphology, with the presence of myelin basic protein in the absence of mature myelin sheaths is reminiscent of the early stages of myelination in the newborn. From a brief review of the literature on Wiedemann-Rautenstrauch syndrome, we conclude, that the neuropathology of the syndrome is heterogeneous, and that there is relationship between the progeroid aspect and pathological myelination.
Resumo:
Maintenance of the blood system is dependent on dormant haematopoietic stem cells (HSCs) with long-term self-renewal capacity. After injury these cells are induced to proliferate to quickly reestablish homeostasis(1). The signalling molecules promoting the exit of HSCs out of the dormant stage remain largely unknown. Here we show that in response to treatment of mice with interferon-alpha (IFN alpha), HSCs efficiently exit G(0) and enter an active cell cycle. HSCs respond to IFN alpha treatment by the increased phosphorylation of STAT1 and PKB/Akt (also known as AKT1), the expression of IFN alpha target genes, and the upregulation of stem cell antigen-1 (Sca-1, also known as LY6A). HSCs lacking the IFN alpha/beta receptor (IFNAR)(2), STAT1 (ref. 3) or Sca-1 (ref. 4) are insensitive to IFN alpha stimulation, demonstrating that STAT1 and Sca-1 mediate IFN alpha-induced HSC proliferation. Although dormant HSCs are resistant to the anti-proliferative chemotherapeutic agent 5-fluoro-uracil(1,5), HSCs pre-treated (primed) with IFN alpha and thus induced to proliferate are efficiently eliminated by 5-fluoro-uracil exposure in vivo. Conversely, HSCs chronically activated by IFN alpha are functionally compromised and are rapidly out-competed by non-activatable Ifnar(-/-) cells in competitive repopulation assays. Whereas chronic activation of the IFN alpha pathway in HSCs impairs their function, acute IFN alpha treatment promotes the proliferation of dormant HSCs in vivo. These data may help to clarify the so far unexplained clinical effects of IFN alpha on leukaemic cells(6,7), and raise the possibility for new applications of type I interferons to target cancer stem cells(8).
Resumo:
Mostramos como as tecnologias da informação, em particular a Internet, estão provocando uma globalização das atividades de recuperação de informação e pesquisa bibliográfica. Apresentamos as diversas formas de interação na Internet e os principais serviços existentes atualmente referentes à recuperação bibliográfica
Resumo:
Kirjoitus liittyy Kansalliskirjaston Galleriassa 9.3. - 27.5.2002. olleeseen Saksalainen kirja Monrepos'n kirjastossa-näyttelyyn.