2,341 research outputs found

    Issues in Managing Small Business Information Systems

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    This pa per addresses three issues in managing small business information systems (SBIS): technical issues, organizational issues, and the approach to information systems investments. Practical guidelines are provided for small business executives.

    Drosophila Decapping Protein 1, dDcp1, Is a Component of the oskar mRNP Complex and Directs Its Posterior Localization in the Oocyte

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    SummaryIn Drosophila, posterior deposition of oskar (osk) mRNA in oocytes is critical for both pole cell and abdomen formation. Exon junction complex components, translational regulation factors, and other proteins form an RNP complex that is essential for directing osk mRNA to the posterior of the oocyte. Until now, it has not been clear whether the mRNA degradation machinery is involved in regulating osk mRNA deposition. Here we show that Drosophila decapping protein 1, dDcp1, is a posterior group gene required for the transport of osk mRNA. In oocytes, dDcp1 is localized posteriorly in an osk mRNA position- and dosage-dependent manner. In nurse cells, dDcp1 colocalizes with dDcp2 and Me31B in discrete foci that may be related to processing bodies (P bodies), which are sites of active mRNA degradation. Thus, as well as being a general factor required for mRNA decay, dDcp1 is an essential component of the osk mRNP localization complex

    Twinning-like lattice reorientation without a crystallographic twinning plane

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    Twinning on the {10[bar over 1]2} plane is a common mode of plastic deformation for hexagonal-close-packed metals. Here we report, by monitoring the deformation of submicron-sized single-crystal magnesium compressed normal to its prismatic plane with transmission electron microscopy, the reorientation of the parent lattice to a ‘twin’ lattice, producing an orientational relationship akin to that of the conventional {10[bar over 1]2} twinning, but without a crystallographic mirror plane, and giving plastic strain that is not simple shear. Aberration-corrected transmission electron microscopy observations reveal that the boundary between the parent lattice and the ‘twin’ lattice is composed predominantly of semicoherent basal/prismatic interfaces instead of the {10[bar over 1]2} twinning plane. The migration of this boundary is dominated by the movement of these interfaces undergoing basal/prismatic transformation via local rearrangements of atoms. This newly discovered deformation mode by boundary motion mimics conventional deformation twinning but is distinct from the latter and, as such, broadens the known mechanisms of plasticity.National Natural Science Foundation (China) (50925104)National Natural Science Foundation (China) (11132006)National Natural Science Foundation (China) (51231005)National Natural Science Foundation (China) (51231003)National Natural Science Foundation (China). 973 Program (2010CB631003)National 111 Project of China (B06025

    Seabed gas emissions and submarine landslides off SW Taiwan

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    Methane emissions out of the seabed could seriously affect Earthâs climate and are usually associated with the dissociation of gas hydrates stored in marine sediments on the continental margins. Spatially, gas emissions out of the seafloor are not evenly distributed in continental margins. Gas emissions out of the seabed generally occur through submarine mud volcanoes and gas seeps. To understand the seabed gas emissions off SW Taiwan, we investigate the distributions of active submarine mud volcanoes, gas seeps, and gas plumes off SW Taiwan. We examine all of the available sub-bottom profiler and EK echo sounder data. We identified 19 submarine mud volcanoes, 220 gas seeps, and 295 gas plumes. The gas emissions are generally distributed at the crests of mud diapiric ridges. Most of the active mud volcanoes and gas seeps cluster at the KASMVG (Kaoping submarine mud volcanoes group) area. We speculate that the intensive mud volcanism and gas seepage at the KASMVG area are ascribed to submarine channel erosion along the continental slope base. The erosion causes a deep V-shaped channel and a steep BSR (Bottom-Simulating Reflector) slope curve across the continental margin. The upward migration rate of free gas beneath the BSR is thus increased and intensifies mud volcanism and gas seepage at the KASMVG area. The gas seeps can reduce the slope stability and generate small-scale slides. The development of mud volcanoes in an area could effectively disturb the seabed morphology so that large-scale submarine landslides cannot easily happen

    Characteristic gene expression profiles in the progression from liver cirrhosis to carcinoma induced by diethylnitrosamine in a rat model

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    <p>Abstract</p> <p>Background</p> <p>Liver cancr is a heterogeneous disease in terms of etiology, biologic and clinical behavior. Very little is known about how many genes concur at the molecular level of tumor development, progression and aggressiveness. To explore the key genes involved in the development of liver cancer, we established a rat model induced by diethylnitrosamine to investigate the gene expression profiles of liver tissues during the transition to cirrhosis and carcinoma.</p> <p>Methods</p> <p>A rat model of liver cancer induced by diethylnitrosamine was established. The cirrhotic tissue, the dysplasia nodules, the early cancerous nodules and the cancerous nodules from the rats with lung metastasis were chosen to compare with liver tissue of normal rats to investigate the differential expression genes between them. Affymetrix GeneChip Rat 230 2.0 arrays were used throughout. The real-time quantity PCR was used to verify the expression of some differential expression genes in tissues.</p> <p>Results</p> <p>The pathological changes that occurred in the livers of diethylnitrosamine-treated rats included non-specific injury, fibrosis and cirrhosis, dysplastic nodules, early cancerous nodules and metastasis. There are 349 upregulated and 345 downregulated genes sharing among the above chosen tissues when compared with liver tissue of normal rats. The deregulated genes play various roles in diverse processes such as metabolism, transport, cell proliferation, apoptosis, cell adhesion, angiogenesis and so on. Among which, 41 upregulated and 27 downregulated genes are associated with inflammatory response, immune response and oxidative stress. Twenty-four genes associated with glutathione metabolism majorly participating oxidative stress were deregulated in the development of liver cancer. There were 19 members belong to CYP450 family downregulated, except CYP2C40 upregulated.</p> <p>Conclusion</p> <p>In this study, we provide the global gene expression profiles during the development and progression of liver cancer in rats. The data obtained from the gene expression profiles will allow us to acquire insights into the molecular mechanisms of hepatocarcinogenesis and identify specific genes (or gene products) that can be used for early molecular diagnosis, risk analysis, prognosis prediction, and development of new therapies.</p
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