3,794 research outputs found

    The Effect of NAGā€“thiazoline on Morphology and Surface Hydrophobicity of Escherichia Coli

    Get PDF
    The Ī²-hexosaminidase inhibitor and structural analog of the putative oxazolium reaction intermediate of lytic transglycosylases, N-acetylglucosamine thiazoline (NAGā€“thiazoline), was synthesized in 46% overall yield and tested as an inhibitor of Escherichia coli growth. NAGā€“thiazoline, at concentrations up to 1 mg/ml, was not found to affect the viability of E. coli DH5Ī±

    Supposed Periodicity of Redpoll, Carduelis sp., Winter Visitations in Atlantic Canada

    Get PDF
    Redpoll (primarily Carduelis flammea) data from the New Brunswick–Nova Scotia border region were reviewed in the context of alleged biennial periodicity of irruptions south of their breeding range. Long-term records by the authors suggested a number of departures from visitation in alternate years. Three local Christmas Bird Counts (CBCs) spanning the last 41 winters supported the less-than-regular pattern shown by individual observations. CBC redpoll data from across the Atlantic Provinces revealed annual redpoll visitations across southern New Brunswick, where the largest regional counts (adjusted for observer effort) usually occurred. Visitation to Prince Edward Island, Nova Scotia, and Newfoundland was less frequent, and patterns there were often obscured by scarcity of CBCs with both long-run coverage and redpolls. Examination of those data in relation to varying food availability suggested that irregular abundance but near-annual occurrence of redpoll visitation explains observed observations better than attempts to find periodicity in their irruptions

    Turbomachinery

    Get PDF
    The discipline research in turbomachinery, which is directed toward building the tools needed to understand such a complex flow phenomenon, is based on the fact that flow in turbomachinery is fundamentally unsteady or time dependent. Success in building a reliable inventory of analytic and experimental tools will depend on how the time and time-averages are treated, as well as on who the space and space-averages are treated. The raw tools at disposal (both experimentally and computational) are truly powerful and their numbers are growing at a staggering pace. As a result of this power, a case can be made that a situation exists where information is outstripping understanding. The challenge is to develop a set of computational and experimental tools which genuinely increase understanding of the fluid flow and heat transfer in a turbomachine. Viewgraphs outline a philosophy based on working on a stairstep hierarchy of mathematical and experimental complexity to build a system of tools, which enable one to aggressively design the turbomachinery of the next century. Examples of the types of computational and experimental tools under current development at Lewis, with progress to date, are examined. The examples include work in both the time-resolved and time-averaged domains. Finally, an attempt is made to identify the proper place for Lewis in this continuum of research

    Turbomachinery

    Get PDF
    The discipline research in turbomachinery, which is directed toward building the tools needed to understand such a complex flow phenomenon, is based on the fact that flow in turbomachinery is fundamentally unsteady or time dependent. Success in building a reliable inventory of analytic and experimental tools will depend on how we treat time and time-averages, as well as how we treat space and space-averages. The challenge is to develop a set of computational and experimental tools which genuinely increase our understanding of the fluid flow and heat transfer in a turbomachine. Examples of the types of computational and experimental tools under current development, with progress to date, are examined. The examples include work in both the time-resolved and time-averaged domains

    Teachers\u27 perceptions of online modules to promote professional learning of ICT

    Get PDF
    Online professional learning has the potential to be a cost effective, flexible approach that can reach large numbers of teachers. However, there are many factors that need to be evaluated in developing successful online approaches that impact on teaching pedagogy and student learning. This paper outlines one phase of a research study conducted on behalf of an Australian state-based Department of Education to evaluate the transfer of professional learning from online modules about the integration of ICT to the practices of K-12 classroom teachers

    Dolichol-linked oligosaccharide selection by the oligosaccharyltransferase in protist and fungal organisms

    Get PDF
    The dolichol-linked oligosaccharide Glc3Man9GlcNAc2-PP-Dol is the in vivo donor substrate synthesized by most eukaryotes for asparagine-linked glycosylation. However, many protist organisms assemble dolichol-linked oligosaccharides that lack glucose residues. We have compared donor substrate utilization by the oligosaccharyltransferase (OST) from Trypanosoma cruzi, Entamoeba histolytica, Trichomonas vaginalis, Cryptococcus neoformans, and Saccharomyces cerevisiae using structurally homogeneous dolichol-linked oligosaccharides as well as a heterogeneous dolichol-linked oligosaccharide library. Our results demonstrate that the OST from diverse organisms utilizes the in vivo oligo saccharide donor in preference to certain larger and/or smaller oligosaccharide donors. Steady-state enzyme kinetic experiments reveal that the binding affinity of the tripeptide acceptor for the protist OST complex is influenced by the structure of the oligosaccharide donor. This rudimentary donor substrate selection mechanism has been refined in fungi and vertebrate organisms by the addition of a second, regulatory dolichol-linked oligosaccharide binding site, the presence of which correlates with acquisition of the SWP1/ribophorin II subunit of the OST complex

    PNNL Coal Gasifier Transportation Logistics

    Get PDF
    This report provides Pacific Northwest National laboratory (PNNL) craftspeople with the necessary information and suggested configurations to transport PNNLā€™s coal gasifier from its current location at the InEnTec facility in Richland, Washington, to PNNLā€™s Laboratory Support Warehouse (LSW) for short-term storage. A method of securing the gasifier equipment is provided that complies with the tie-down requirements of the Federal Motor Carrier Safety Administrationā€™s Cargo Securement Rules

    Engineering novel complement activity into a pulmonary surfactant protein

    Get PDF
    Complement neutralizes invading pathogens, stimulates inflammatory and adaptive immune responses, and targets non- or altered-self structures for clearance. In the classical and lectin activation pathways, it is initiated when complexes composed of separate recognition and activation subcomponents bind to a pathogen surface. Despite its apparent complexity, recognition-mediated activation has evolved independently in three separate protein families, C1q, mannose-binding lectins (MBLs), and serum ficolins. Although unrelated, all have bouquet-like architectures and associate with complement-specific serine proteases: MBLs and ficolins with MBL-associated serine protease-2 (MASP-2) and C1q with C1r and C1s. To examine the structural requirements for complement activation, we have created a number of novel recombinant rat MBLs in which the position and orientation of the MASP-binding sites have been changed. We have also engineered MASP binding into a pulmonary surfactant protein (SP-A), which has the same domain structure and architecture as MBL but lacks any intrinsic complement activity. The data reveal that complement activity is remarkably tolerant to changes in the size and orientation of the collagenous stalks of MBL, implying considerable rotational and conformational flexibility in unbound MBL. Furthermore, novel complement activity is introduced concurrently with MASP binding in SP-A but is uncontrolled and occurs even in the absence of a carbohydrate target. Thus, the active rather than the zymogen state is default in lectinĀ·MASP complexes and must be inhibited through additional regions in circulating MBLs until triggered by pathogen recognition
    • ā€¦
    corecore