270 research outputs found

    PLP - A Package for Parametric Programming

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    This paper is one of the series of 11 Working Papers presenting the software for interactive decision support and software tools for developing decision support system. These products constitute the outcome of the contracted study agreement between the System and Decision Sciences Program at IIASA and several Polish scientific institutions. The theoretical part of these results is presented in the IIASA Working Paper WP-88-071 entitled "Theory, Software and Testing Examples in Decision Support Systems" which contains the theoretical and methodological backgrounds of the software systems developed within the project. This paper presents the PLP package for parametric linear programming. This package constitutes the extension to MINOS, the well known linear and nonlinear programming code developed at Stanford University, and uses the MINOS as the solver of optimization problems. The PLP gives a complete parametric programming analysis for one, or more, of the following vectors: cost, rhs and bounds. In the same run several problems of this kind can be solved and for each, the starting point may be the original optimal solution obtained in the last problem. This property makes the PLP especially interesting for multiple criteria analysis using the reference point approach

    G Protein-Coupled Odorant Receptors: from sequence to structure

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    Odorant receptors (ORs) are the largest sub-family within Class-A G Protein-Coupled Receptors (GPCRs). No experimental structural data of any OR is available to date and atomic-level insights are likely to be obtained by means of molecular modeling. In this article, we critically align sequences of ORs with those GPCRs for which a structure is available. Here, an alignment consistent with available site-directed mutagenesis data on various ORs is proposed. Using this alignment, the choice of the template is deemed rather minor for identifying residues that constitute the wall of the binding cavity or those involved in G-protein recognition

    Mapping the Corneal Sub-Basal Nerve Plexus in Orthokeratology Lens Wear Using in vivo Laser Scanning Confocal Microscopy

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    PURPOSE. This study was designed to map the sub-basal nerve plexus (SBNP) in the cornea of orthokeratology (OK) lens wearers. METHODS. Laser scanning confocal microscopy (LSCM) was performed in vivo on three subjects: a non-lens wearer and two OK lens wearers. Scans were performed on the right eye while the left eye fixated a moving target. A total of 575, 430, and 676 contiguous images of the SBNP were taken from the non-lens wearing and the OK lens wearing subjects, respectively, and used to construct maps of the central to midperipheral SBNP. RESULTS. In the non-lens wearing eye, nerves radiated towards a whorl-like complex centered nasally and inferiorly in an overall pattern consistent with previously reported studies. In the OK lens wearing eyes, this whorl pattern was absent, replaced by a tortuous network of nerve fibers centrally, and thicker curvilinear fibers mid-peripherally, particularly in the nasal, inferior, and temporal regions. CONCLUSIONS. This study maps the corneal SBNP in OK lens wearers and provides compelling evidence that OK lens wear alters the normal SBNP distribution observed in healthy, nonlens wearing eyes. (Invest Ophthalmol Vis Sci

    Visible camera cryostat design and performance for the SuMIRe Prime Focus Spectrograph (PFS)

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    We describe the design and performance of the SuMIRe Prime Focus Spectrograph (PFS) visible camera cryostats. SuMIRe PFS is a massively multi-plexed ground-based spectrograph consisting of four identical spectrograph modules, each receiving roughly 600 fibers from a 2394 fiber robotic positioner at the prime focus. Each spectrograph module has three channels covering wavelength ranges 380~nm -- 640~nm, 640~nm -- 955~nm, and 955~nm -- 1.26~um, with the dispersed light being imaged in each channel by a f/1.07 vacuum Schmidt camera. The cameras are very large, having a clear aperture of 300~mm at the entrance window, and a mass of \sim280~kg. In this paper we describe the design of the visible camera cryostats and discuss various aspects of cryostat performance

    Global Reprogramming of Host SUMOylation during Influenza Virus Infection

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    Dynamic nuclear SUMO modifications play essential roles in orchestrating cellular responses to proteotoxic stress, DNA damage, and DNA virus infection. Here,we describe a non-canonical host SUMOylation response to the nuclear-replicating RNA pathogen, influenza virus, and identify viral RNA polymerase activity as a major contributor to SUMO proteome re-modeling. Using quantitative proteomics to compare stress-induced SUMOylation responses, we reveal that influenza virus infection triggers unique re-targeting of SUMO to 63 host proteins involved in transcription, mRNA processing, RNA quality control, and DNA damage repair. This is paralleled by widespread host deSUMOylation. Depletion screening identified ten virus-induced SUMO targets as potential antiviral factors, including C18orf25 and the SMC5/6 and PAF1 complexes. Mechanistic studies further uncovered a role for SUMOylation of the PAF1 complex component, parafibromin (CDC73), in potentiating antiviral gene expression. Our global characterization of influenza virus-triggered SUMO redistribution provides a proteomic resource to understand host nuclear SUMOylation responses to infection

    Current status of the Spectrograph System for the SuMIRe/PFS

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    The Prime Focus Spectrograph (PFS) is a new facility instrument for Subaru Telescope which will be installed in around 2017. It is a multi-object spectrograph fed by about 2400 fibers placed at the prime focus covering a hexagonal field-of-view with 1.35 deg diagonals and capable of simultaneously obtaining data of spectra with wavelengths ranging from 0.38 um to 1.26 um. The spectrograph system is composed of four identical modules each receiving the light from 600 fibers. Each module incorporates three channels covering the wavelength ranges 0.38-0.65 mu ("Blue"), 0.63-0.97 mu ("Red"), and 0.94-1.26 mu ("NIR") respectively; with resolving power which progresses fairly smoothly from about 2000 in the blue to about 4000 in the infrared. An additional spectral mode allows reaching a spectral resolution of 5000 at 0.8mu (red). The proposed optical design is based on a Schmidt collimator facing three Schmidt cameras (one per spectral channel). This architecture is very robust, well known and documented. It allows for high image quality with only few simple elements (high throughput) at the expense of the central obscuration, which leads to larger optics. Each module has to be modular in its design to allow for integration and tests and for its safe transport up to the telescope: this is the main driver for the mechanical design. In particular, each module will be firstly fully integrated and validated at LAM (France) before it is shipped to Hawaii. All sub-assemblies will be indexed on the bench to allow for their accurate repositioning. This paper will give an overview of the spectrograph system which has successfully passed the Critical Design Review (CDR) in 2014 March and which is now in the construction phase.Comment: 9 pages, 7 figures, submitted to "Ground-based and Airborne Instrumentation for Astronomy V, Suzanne K. Ramsay, Ian S. McLean, Hideki Takami, Editors, Proc. SPIE 9147 (2014)

    SUBARU prime focus spectrograph: integration, testing and performance for the first spectrograph

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    The Prime Focus Spectrograph (PFS) of the Subaru Measurement of Images and Redshifts (SuMIRe) project for Subaru telescope consists in four identical spectrographs fed by 600 fibers each. Each spectrograph is composed by an optical entrance unit that creates a collimated beam and distributes the light to three channels, two visibles and one near infrared. This paper presents the on-going effort for the tests & integration process for the first spectrograph channel: we have developed a detailed Assembly Integration and Test (AIT) plan, as well as the methods, detailed processes and I&T tools. We describe the tools we designed to assemble the parts and to test the performance of the spectrograph. We also report on the thermal acceptance tests we performed on the first visible camera unit. We also report on and discuss the technical difficulties that did appear during this integration phase. Finally, we detail the important logistic process that is require to transport the components from other country to Marseille

    Fast automated placement of polar hydrogen atoms in protein-ligand complexes

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    <p>Abstract</p> <p>Background</p> <p>Hydrogen bonds play a major role in the stabilization of protein-ligand complexes. The ability of a functional group to form them depends on the position of its hydrogen atoms. An accurate knowledge of the positions of hydrogen atoms in proteins is therefore important to correctly identify hydrogen bonds and their properties. The high mobility of hydrogen atoms introduces several degrees of freedom: Tautomeric states, where a hydrogen atom alters its binding partner, torsional changes where the position of the hydrogen atom is rotated around the last heavy-atom bond in a residue, and protonation states, where the number of hydrogen atoms at a functional group may change. Also, side-chain flips in glutamine and asparagine and histidine residues, which are common crystallographic ambiguities must be identified before structure-based calculations can be conducted.</p> <p>Results</p> <p>We have implemented a method to determine the most probable hydrogen atom positions in a given protein-ligand complex. Optimality of hydrogen bond geometries is determined by an empirical scoring function which is used in molecular docking. This allows to evaluate protein-ligand interactions with an established model. Also, our method allows to resolve common crystallographic ambiguities such as as flipped amide groups and histidine residues. To ensure high speed, we make use of a dynamic programming approach.</p> <p>Conclusion</p> <p>Our results were checked against selected high-resolution structures from an external dataset, for which the positions of the hydrogen atoms have been validated manually. The quality of our results is comparable to that of other programs, with the advantage of being fast enough to be applied on-the-fly for interactive usage or during score evaluation.</p
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