Browsing by Author "Yang, Wei"

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    Development of a Web-Based System for Water Quality Data Management and Visualization
    Yang, Wei (Virginia Tech, 2010-05-03)
    With increasing urbanization and population growth, humankind faces multiple environmental challenges. Stresses on limited resources, especially water resources, are now greater than ever before. Watershed monitoring and management are important components of programs to abate water resource stresses. The increasing water quantity and quality monitoring has produced a need for better data management techniques to manage the vast amount of watershed monitoring data being observed. These data must be stored, error checked, manipulated, retrieved and shared with the watershed management community. The web-based data visualization and analysis technology has played a critical role in all aspects of watershed management. Especially in recent years, computer-assisted data analysis has matured enormously. This maturing technology makes web-based visualization and analysis technology change its role to become an integrated system which combines applications of databases, and internet technology. The main objective of this study is to develop a prototype system which has ability of data visualization and analysis. Microsoft SQL Server is used to build a comprehensive database, which includes all datasets collected by OWML. A Web-Based Data Visualization and Analysis System which provides an integrated interface for permitted users to explore, analyze and download data has been developed.
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    Identification of county-level health factors associated with COVID-19 mortality in the United States
    Pan, Wei; Miyazaki, Yasuo; Tsumura, Hideyo; Miyazaki, Emi; Yang, Wei (Journal of Biomedical Research, 2020-11-01)
    Many studies have investigated causes of COVID-19 and explored safety measures for preventing COVID-19 infections. Unfortunately, these studies fell short to address disparities in health status and resources among decentralized communities in the United States. In this study, we utilized an advanced modeling technique to examine complex associations of county-level health factors with COVID-19 mortality for all 3141 counties in the United States. Our results indicated that counties with more uninsured people, more housing problems, more urbanized areas, and longer commute are more likely to have higher COVID-19 mortality. Based on the nationwide population-based data, this study also echoed prior research that used local data, and confirmed that county-level sociodemographic factors, such as more Black, Hispanic, and older subpopulations, are attributed to high risk of COVID-19 mortality. We hope that these findings will help set up priorities on high risk communities and subpopulations in future for fighting the novel virus.
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    Studies on the structural organization of Golgi complex
    Yang, Wei (Virginia Tech, 1995)
    Golgi complex is a multi-compartmental organelle involved in posttranslational modification and sorting of secretory proteins. We have characterized the distribution in Vero cells of three Golgi cisternal membrane proteins, Sialyltransferase (SialylT, tans- Golgi/TGN), galactosyltransferase(GalT, trans-Golgi/TGN), and Nacetylglucosametransferase- 1 (GlcNAcT-1, medial-Golgi), during the process of Golgi disassembly and reassembly following the addition or removal of drugs. After 1 h nocodazole (microtubule depolymerizer) treatment, SialylT and GalT were found in scattered punctate structures that increased in number over time as less and less of these proteins were found perinuclearly. Initially these punctate structures were often negative for GlcNAcT-1. Over a 2 to 3-fold slower time course, GICNAcT-1 co-localized with SialylT and GalT in the scattered punctate structures. Cis-Golgi network marker was found in a separate set of scattered punctate structures from that of cisternae even at 4 h following nocodazole addition. Following nocodazole removal, all the cisternal markers accumulated perinuclearly into a reassembled Golgi at the same rate. After brefeldin A treatment (coat protein inhibitor), all the cisternae markers dispersed to ER with similar kinetics, albeit, in some cases by different tubular extensions of the Golgi. GlicCNAcT-1 and GalT showed similar kinetics of Golgi reassembly following BFA removal while SialylT lagged somewhat behind. Our data suggest that CGN, medial-Golgi and trans-Golgi/TGN are distinct subcompartments that can be separated one from the other by drug treatment; any exchange of components between the Golgi subcompartments must be slow with respect to the observed kinetics of Golgi disassembly. An epitope tagging approach was used to delineate the importance of the above Golgi protein's cytoplasmic tail domain in Golgi targeting and retention. we found that the cytoplasmic tail could be lengthened considerably (3-4 fold) and SialyIT and GalT still accumulated in a perinuclear, Golgi-like distribution with little ER background. One construct, VSV-SialylT, localized essentially exclusively to the Golgi complex. For SialylT, the longest constructs (40-42 amino acids) located relatively well to the Golgi complex while for GalT, the longest constructs (32-34 amino acids) located exclusively to the ER. Surprisingly, the epitope tags of several different GalT constructs was inaccessible to antibody in fixed cells. Any lengthening of the cytoplasmic domain of GIcNAcT-1 resulted in considerable to exclusive accumulation of the chimeric proteins in ER. No cell surface accumulation of any of the chimeric proteins was detected. The specific sequence of the epitope tag was important; the neutral to positively charged VSV epitope tag was preferred over negatively charged myc or FLAG tags. Depending on the exact tail alteration, we found that all three transferases accumulated in the ER with no detectable Golgi or cell surface accumulation. In some cases accumulation in the intermediate compartment or CGN was observed. Most surprisingly, in the one homologous case studied, expression of chimeric human GlcNAcT-1 in HeLa cells, ER accumulation of GlcNAcT-1 led to disruption of pre-existing Golgi. Based on these results, we propose, as the simplest explanation of the data, that alteration of the cytoplasmic tail of Golgi resident proteins can decrease their rate of exit from ER, presumably due to premature oligomerization, and may lead to capture of Golgi proteins in ER.