3,648 research outputs found

    Heterogeneity of Nicotinic Receptor Class and Subunit mRNA Expression among Individual Parasympathetic Neurons from Rat Intracardiac Ganglia

    Get PDF
    Neurons have the potential to form thousands of distinct neuronal nicotinic receptors from the eight alpha and three beta subunits that currently are known. In an effort to determine how much of this potential complexity is realized among individual neurons, we examined the nicotinic pharmacological and biophysical properties and receptor subunit mRNA expression patterns in individual neurons cultured from rat epicardial ganglia. Analysis of the whole-cell pharmacology of these neurons showed a diversity of responses to the agonists acetylcholine, nicotine, cytisine, and 1,1-dimethyl-4-phenylpiperazinium, suggesting that a heterogeneous population of nicotinic receptor classes, or subtypes, is expressed by individual neurons. Single-channel analysis demonstrated three distinct conductances (18, 24, and 31 pS), with patches from different neurons containing different combinations of these channel classes. We used single-cell RT-PCR to examine nicotinic acetylcholine receptor (nAChR) subunit mRNA expression by individual neurons. Although mRNAs encoding all eight neuronal nAChR subunits for which we probed (alpha 2-alpha 5, alpha 7, beta 2-beta 4) were present in multicellular cultures, we found that individual epicardial neurons express distinct subsets of these nAChR subunit mRNAs. These results suggest that individual epicardial neurons express distinct arrays of nAChR subunits and that these subunits may assemble into functional receptors with distinct and variable subunit composition. This variable receptor subunit expression provides an explanation for the diversity of pharmacological and single-channel responses we have observed in individual neurons

    NAVY EXPEDITIONARY ADDITIVE MANUFACTURING (NEAM) CAPABILITY INTEGRATION

    Get PDF
    This capstone report analyzes the current and future use of additive manufacturing (AM) technologies within the Department of Defense (DOD). This analysis provided the technical background necessary to develop the Additive Manufacturing Process and Analysis Tool (AMPAT). AMPAT will help stakeholders identify what AM equipment best serves warfighters and their missions in expeditionary environments. Furthermore, the tool can be used by stakeholders to identify the most advantageous dispersions of AM capabilities across the fleet and make decisions on how those capabilities should be integrated into the greater naval mission and larger DOD enterprise. A systems engineering (SE) approach was implemented to gather information on current and prospective AM methods in order to understand and define the AM system operational requirements. Additionally, an SE process was utilized to analyze alternative software options to build the tool, implement agile software development processes to develop the tool, and verify and validate that the tool met the project requirements. The study found that AMPAT successfully outputs a ranked list of AM systems recommendations based upon user-defined input parameters and weighting values. Recommendations for choosing AM equipment and developing dispersion plans for the fleet include using the AMPAT deliverable to conduct customized, iterative analysis with user-defined inputs that are tailored to specific expeditionary environments.Outstanding ThesisCivilian, Department of the NavyCivilian, Department of the NavyCivilian, Department of the NavyCivilian, Department of the ArmyCivilian, Department of the NavyApproved for public release. Distribution is unlimited

    Diversity of Lecidea (Lecideaceae, Ascomycota) species revealed by molecular data and morphological characters

    Get PDF
    The diversity of lichens, especially crustose species, in continental Antarctica is still poorly known. To overcome difficulties with the morphology based species delimitations in these groups, we employed molecular data (nuclear ITS and mitochondrial SSU rDNA sequences) to test species boundaries within the genus Lecidea. Sampling was done along a north–south transect at five different areas in the Ross Sea region (Cape Hallett, Botany Bay to Mount Suess, Taylor Valley, Darwin Area and Mount Kyffin). A total of 153 specimens were collected from 13 localities. Phylogenetic analyses also include specimens from other regions in Antarctica and non-Antarctic areas. Maximum parsimony, maximum likelihood and Bayesian analyses agreed in placing the samples from continental Antarctica into four major groups. Based on this phylogenetic estimate, we restudied the micromorphology and secondary chemistry of these four clades to evaluate the use of these characters as phylogenetic discriminators. These clades are identified as the following species Lecidea cancriformis, L. andersonii as well as the new species L. polypycnidophora Ruprecht & Türk sp. nov. and another previously unnamed clade of uncertain status, referred to as Lecidea sp. (L. UCR1)
    corecore