53 research outputs found

    MGOS: A library for molecular geometry and its operating system

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    The geometry of atomic arrangement underpins the structural understanding of molecules in many fields. However, no general framework of mathematical/computational theory for the geometry of atomic arrangement exists. Here we present "Molecular Geometry (MG)'' as a theoretical framework accompanied by "MG Operating System (MGOS)'' which consists of callable functions implementing the MG theory. MG allows researchers to model complicated molecular structure problems in terms of elementary yet standard notions of volume, area, etc. and MGOS frees them from the hard and tedious task of developing/implementing geometric algorithms so that they can focus more on their primary research issues. MG facilitates simpler modeling of molecular structure problems; MGOS functions can be conveniently embedded in application programs for the efficient and accurate solution of geometric queries involving atomic arrangements. The use of MGOS in problems involving spherical entities is akin to the use of math libraries in general purpose programming languages in science and engineering. (C) 2019 The Author(s). Published by Elsevier B.V

    Design of 6U Nanosatellites in Formation Flying for the Laser Crosslink Mission

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    With a recent growth in the volume of spaceborne data, free space optical (FSO) or laser communication systems are attracting attention, as they can enable super-high data rates faster than 1 Gbps. The Very high-speed Inter-satellite link Systems using Infrared Optical terminal and Nanosatellite (VISION) is a technical demonstration mission to establish and validate laser crosslink systems using two 6U nanosatellites in formation flying. The final goal is to achieve a Gbps-level data rate at a distance of thousands of kilometers. To establish space-to-space laser communication, the payload optical axes of each satellite should be precisely aligned during the crosslink. The payload is the laser communication terminal (LCT) including the deployable space telescope (DST), which improves optical link performances. The 6U nanosatellite bus is designed with commercial off-the shelf-(COTS) components for agile systems development. For precise formation flying, the bus is equipped a with relative navigation system with a GNSS receiver and RF crosslink, star tracker, 3-axis reaction wheels (RWs), and propulsion system. This proposed concept of the laser crosslink systems will contribute to the construction of the LEO communication constellation with high speed and secure links in future

    Atherosclerotic Progression Attenuates the Expression of Nogo-B in Autopsied Coronary Artery: Pathology and Virtual Histology Intravascular Ultrasound Analysis

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    The relation of Nogo-B to atherosclerotic plaque progression is not well understood. Thus, the purpose of this study was to assess the expression of Nogo-B in fibroatheromas (FA) of different stages, classified using virtual histology intravascular ultrasound (VH-IVUS) analysis in 19 autopsied cases of non-sudden cardiac death. VH-IVUS imaging analysis was performed 30 mm from the ostium of each coronary artery. VH-IVUS revealed 11 early FAs (34.5±8.3 yr), 12 late FAs (42.6±16.6 yr), 8 thick-cap FAs (TkCFAs) (46.4±11.1 yr), and 6 thin-cap FAs (TCFAs) (51.8±6.8 yr). TkCFAs and TCFAs were defined as advanced FA. FA progression advanced with age (P=0.04). VH-IVUS analysis of small, early FAs showed smaller necrotic cores and relatively less calcium compared to more advanced FAs with large necrotic cores (P<0.001). Histopathology and immunohistochemical stains demonstrated that early or late FAs had smaller necrotic cores, less empty space of decalcification, and greater Nogo-B expression compared to advanced FAs (vs. early FA, P=0.013; vs. late FA, P=0.008, respectively). These findings suggest that FA progression is inversely associated with Nogo-B expression. Local reduction of Nogo-B may contribute to plaque formation and/or instability

    Vacuolar (H+)-ATPases in Caenorhabditis elegans: What can we learn about giant H+ pumps from tiny worms?

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    AbstractVacuolar (H+)-ATPases, also called V-ATPases, are ATP-driven proton pumps that are highly phylogenetically conserved. Early biochemical and cell biological studies have revealed many details of the molecular mechanism of proton pumping and of the structure of the multi-subunit membrane complex, including the stoichiometry of subunit composition. In addition, yeast and mouse genetics have broadened our understanding of the physiological consequences of defective vacuolar acidification and its related disease etiologies. Recently, phenotypic investigation of V-ATPase mutants in Caenorhabditis elegans has revealed unexpected new roles of V-ATPases in both cellular function and early development. In this review, we discuss the functions of the V-ATPases discovered in C. elegans

    Preliminary X-ray diffraction study of glutathione S-transferase from Pseudomonas sp. DJ77

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    A bacterial glutathione S-transferase from Pseudomonas sp. DJ77 has been crystallized. The crystals diffract to at least 2.3 ? resolution, and belong to the orthorhombic space group P212121, with cell parameters a=97.4 ?, b=100.3 ?, and c=46.0 ?. There is one dimer molecule of pGST per crystallographic asymmetric unit, with the crystal volume per protein mass of 2.34 ?3/dalton and a solvent content of about 47% (v/v).ope
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