807 research outputs found

    Correlative Light and Electron Microscopy of Platelet Adhesion and Fibrinogen Receptor Expression using Colloidal-Gold Labeling

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    Differences in the shape change responses of platelets to various polymers may determine the thrombotic potential of these materials. Substrate-dependent variation in the expression and motility of the platelet fibrinogen receptor may underlie these differences due to this ligand\u27s essential role in platelet aggregation. In this study we examine platelet activation on polyetherurethaneureas (PEUUs) presently being evaulated for vascular prosthetic applications. These polymers are prepared as 50-100nm thin films suitable as substrates for consecutive light microscopy, high voltage electron microscopy (HVEM), and SEM. 18nm colloidal gold coupled to fibrinogen permits visualization of that receptor\u27s motility in living cells by video-enhanced light microscopy. Subsequent HVEM and SEM of identified cells provides correlative ultrastructure and surface morphology. The use of these novel support films coupled with the multiple modes of microscopy and colloidal gold labeled ligands permits in depth study of the molecular biology of cell adhesion to materials with varied, and known, surface properties. The motility of the platelet fibrinogen receptor was related to the extent of cytoskeletal reorganization, which, in turn, was influenced by polymer surface energetics. Platelets adherent to more hydrophobic PEUUs had greater receptor mobility and receptor redistribution than platelets adherent to more hydrophilic PEUUs. The most extensive receptor motility and redistribution was observed on Formvar, a non-PEUU with low surface-water energy, suggesting that additional surface properties are of importance in determining platelet spreading and fibrinogen receptor motility

    The birds of the Egyptian western desert

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    http://deepblue.lib.umich.edu/bitstream/2027.42/56416/1/MP172.pd

    Global water cycle

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    The primary objective is to determine the scope and interactions of the global water cycle with all components of the Earth system and to understand how it stimulates and regulates changes on both global and regional scales. The following subject areas are covered: (1) water vapor variability; (2) multi-phase water analysis; (3) diabatic heating; (4) MSU (Microwave Sounding Unit) temperature analysis; (5) Optimal precipitation and streamflow analysis; (6) CCM (Community Climate Model) hydrological cycle; (7) CCM1 climate sensitivity to lower boundary forcing; and (8) mesoscale modeling of atmosphere/surface interaction

    Assessment of Rainfall Estimates Using a Standard Z-R Relationship and the Probability Matching Method Applied to Composite Radar Data in Central Florida

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    Precipitation estimates from radar systems are a crucial component of many hydrometeorological applications, from flash flood forecasting to regional water budget studies. For analyses on large spatial scales and long timescales, it is frequently necessary to use composite reflectivities from a network of radar systems. Such composite products are useful for regional or national studies, but introduce a set of difficulties not encountered when using single radars. For instance, each contributing radar has its own calibration and scanning characteristics, but radar identification may not be retained in the compositing procedure. As a result, range effects on signal return cannot be taken into account. This paper assesses the accuracy with which composite radar imagery can be used to estimate precipitation in the convective environment of Florida during the summer of 1991. Results using Z = 30OR(sup 1.4) (WSR-88D default Z-R relationship) are compared with those obtained using the probability matching method (PMM). Rainfall derived from the power law Z-R was found to he highly biased (+90%-l10%) compared to rain gauge measurements for various temporal and spatial integrations. Application of a 36.5-dBZ reflectivity threshold (determined via the PMM) was found to improve the performance of the power law Z-R, reducing the biases substantially to 20%-33%. Correlations between precipitation estimates obtained with either Z-R relationship and mean gauge values are much higher for areal averages than for point locations. Precipitation estimates from the PMM are an improvement over those obtained using the power law in that biases and root-mean-square errors are much lower. The minimum timescale for application of the PMM with the composite radar dataset was found to be several days for area-average precipitation. The minimum spatial scale is harder to quantify, although it is concluded that it is less than 350 sq km. Implications relevant to the WSR-88D system are discussed

    Should Aggressive Surgical Local Control Be Attempted in All Patients with Metastatic or Pelvic Ewing's Sarcoma?

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    In previous reports, patients with Ewing's sarcoma received radiation therapy (XRT) for definitive local control because metastatic disease and pelvic location were thought to preclude aggressive local treatment. We sought to determine if single-site metastatic disease should be treated differently from multicentric-metastatic disease. We also wanted to reinvestigate the impact of XRT, pelvic location, and local recurrence on outcomes. Our results demonstrated a significant difference in overall survival (OS) between patients with either localized disease or a single-metastatic site and patients with multicentric-metastatic disease (P = 0.004). Local control was also found to be an independent predictor of outcomes as demonstrated by a significant difference in OS between those with and without local recurrence (P = 0.001). Axial and pelvic location did not predict a decreased OS. Based on these results, we concluded that pelvic location and the diagnosis of metastatic disease at diagnosis should not preclude aggressive local control, except in cases of multicentric-metastatic disease

    Precision Farming by Cotton Producers in Six Southern States: Results from the 2001 Southern Precision Farming Survey

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    Precision Farming by Cotton Producers in Six Southern States: Results from the 2001 Southern Precision Farming Surveycotton, precision farming, survey, Agribusiness, Farm Management, Production Economics, Research and Development/Tech Change/Emerging Technologies,

    Precision Farming by Cotton Producers in Eleven Southern States: Results from the 2005 Southern Precision Farming Survey

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    Precision Farming by Cotton Producers in Eleven Southern States: Results from the 2005 Southern Precision Farming Surveycotton, precision farming, survey, Agribusiness, Farm Management, Production Economics, Research and Development/Tech Change/Emerging Technologies,

    The Dystrophin Complex Controls BK Channel Localization and Muscle Activity in Caenorhabditis elegans

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    Genetic defects in the dystrophin-associated protein complex (DAPC) are responsible for a variety of pathological conditions including muscular dystrophy, cardiomyopathy, and vasospasm. Conserved DAPC components from humans to Caenorhabditis elegans suggest a similar molecular function. C. elegans DAPC mutants exhibit a unique locomotory deficit resulting from prolonged muscle excitation and contraction. Here we show that the C. elegans DAPC is essential for proper localization of SLO-1, the large conductance, voltage-, and calcium-dependent potassium (BK) channel, which conducts a major outward rectifying current in muscle under the normal physiological condition. Through analysis of mutants with the same phenotype as the DAPC mutants, we identified the novel islo-1 gene that encodes a protein with two predicted transmembrane domains. We demonstrate that ISLO-1 acts as a novel adapter molecule that links the DAPC to SLO-1 in muscle. We show that a defect in either the DAPC or ISLO-1 disrupts normal SLO-1 localization in muscle. Consistent with observations that SLO-1 requires a high calcium concentration for full activation, we find that SLO-1 is localized near L-type calcium channels in muscle, thereby providing a mechanism coupling calcium influx with the outward rectifying current. Our results indicate that the DAPC modulates muscle excitability by localizing the SLO-1 channel to calcium-rich regions of C. elegans muscle

    Rural/Nonrural Differences in Colorectal Cancer Incidence in the United States, 1998--2001

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    BACKGROUND. Few studies of colorectal cancer incidence by rural, suburban, and metropolitan residence have been published. METHODS. The authors examined colorectal cancer incidence among men and women in U.S. counties classified as rural, suburban, and metropolitan for the period 1998–2001. They examined rural/suburban/metropolitan differences in incidence by age, race, Hispanic ethnicity, stage at diagnosis, histology, and percentage of the total county population below the poverty level, using data from the CDC’s National Program of Cancer Registries, the NCI’s Surveillance, Epidemiology, and End Results Program, and the 2000 U.S. Census. RESULTS. A total of 495,770 newly diagnosed or incident cases of colorectal cancer were included in this analysis (249,919 among men and 245,851 among women). Over the period 1998–2001, the colorectal cancer incidence rates among men tended to be lower among those who resided in rural areas, for each of the subgroups examined, with the exception of Asians and Pacific Islanders and those living in more affluent counties. Among women aged 75 years and older, the colorectal cancer incidence rates tended to be lower among rural than metropolitan or suburban residents, though the differences were slight. In multivariate analysis, the incidence of colorectal cancer was higher in metropolitan, suburban, and rural areas for blacks than that for whites (incidence rate ratios [RR] = 1.12, 1.07, and 1.06, respectively, all P \u3c 0.015). CONCLUSIONS. This study suggests that black men who reside in metropolitan areas have a higher risk of colorectal cancer than black men who reside in rural areas. This finding suggests the need for diverse approaches for reducing colorectal cancer when targeting rural compared with metropolitan areas
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