24 research outputs found

    Experimental Benchmarks and Initial Evaluation of the Performance of the PASM System Prototype

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    The work reported here represents experiences with the PASM parallel processing system prototype during its first operational year. Most of the experiments were performed by students in the Fall semester of 1987. The first programming, and the first timing measurements, were made during the summer of 1987 by Sam Fineberg. The goal of the collection of experiments presented here was to undertake an Application-driven Architecture Study of the PASM system as a paradigm for parallel architecture evaluation in general. PASM was an excellent vehicle for experimenting with this evaluation technique due to its unique architectural features. Among these are: 1. A reconfigurable, partitionable multistage circuit-switched network. 2. Support for both SIMD and MIMD programs. 3. Ability to execute hybrid SIMD/MIMD programs. 4. An instruction queue which allows overlap of control-flow and data manipulation between micro-control (MC) units and processing elements (PE). It had been hypothesized that superlinear speed-up over the number of PEs could be attained with this feature, and experimental results verified this. 5. Support for barrier synchronization of MIMD tasks. This feature was exploited in some non-standard ways to show the ability to decouple variant length SIMD instructions into multiple MIMD streams for an overall performance benefit. This type of study is expected to continue in the future on PASM and other parallel machines at Purdue. This report should serve as a guide for this future work as well

    Systemically Administered Ligands of Toll-Like Receptor 2, -4, and -9 Induce Distinct Inflammatory Responses in the Murine Lung

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    Objective. To determine whether systemically administered TLR ligands differentially modulate pulmonary inflammation. Methods. Equipotent doses of LPS (20 mg/kg), CpG-ODN (1668-thioat 1 nmol/g), or LTA (15 mg/kg) were determined via TNF activity assay. C57BL/6 mice were challenged intraperitoneally. Pulmonary NFκB activation (2 h) and gene expression/activity of key inflammatory mediators (4 h) were monitored. Results. All TLR ligands induced NFκB. LPS increased the expression of TLR2, 6, and the cytokines IL-1αβ, TNF-α, IL-6, and IL-12p35/p40, CpG-ODN raised TLR6, TNF-α, and IL12p40. LTA had no effect. Additionally, LPS increased the chemokines MIP-1α/β, MIP-2, TCA-3, eotaxin, and IP-10, while CpG-ODN and LTA did not. Myeloperoxidase activity was highest after LPS stimulation. MMP1, 3, 8, and 9 were upregulated by LPS, MMP2, 8 by CpG-ODN and MMP2 and 9 by LTA. TIMPs were induced only by LPS. MMP-2/-9 induction correlated with their zymographic activities. Conclusion. Pulmonary susceptibility to systemic inflammation was highest after LPS, intermediate after CpG-ODN, and lowest after LTA challenge

    Bis-[3]Ferrocenophanes with Central >E-E'<Bonds (E, E'=P, SiH) : Preparation, Properties, and Thermal Activation

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    Cover profile:10.1002/open.201900279.Invited for this month's cover picture are the groups of Professors Rudolf Pietschnig at the University of Kassel, Professor Dietrich Gudat at the University of Stuttgart and Professor Laszlo Nyulaszi at the Budapest University of Technology and Economics. The cover picture shows the thermally induced homolytic cleavage of the central P-P bond in a phosphorus-rich bis-ferrocenophane furnishing P-centered radicals (as evidenced by the computed spin-density highlighted in blue). The central P-6 unit in the title compound is a structural analog of the connecting unit in Hittorf's violet phosphorus, which links the orthogonally arranged tubular entities. A portrait of the German physicist Johann Wilhelm Hittorf is included. Read the full text of their Full Paper at 10.1002/open.201900182.Peer reviewe

    Design of a fail-safe embedded controller PRO CHIP PROMETHEUS Phase 2. Final report

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    Available from TIB Hannover: F93B779+a / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEBundesministerium fuer Forschung und Technologie (BMFT), Bonn (Germany)DEGerman

    Ruthenium Complexes with Vinyl, Styryl, and Vinylpyrenyl Ligands: A Case of Non-Innocence in Organometallic Chemistry

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    We herein describe a systematic account of mononuclear ruthenium vinyl complexes L−{Ru}−CHCH−R where the phosphine ligands at the (PR‘3)2Ru(CO)Cl{Ru} moiety, the coordination number at the metal (L = 4-ethylisonicotinate or a vacant coordination site) and the substituent R (R = nbutyl, phenyl, 1-pyrenyl) have been varied. Structures of the enynyl complex Ru(CO)Cl(PPh3)2(η1:η2-nBuHCCHCCnBu), which results from the coupling of the hexenyl ligand of complex 1a with another molecule of 1-hexyne, of the hexenyl complexes (nBuCHCH)Ru(CO)Cl(PiPr3)2 (1c) and (nBuCHCH)Ru(CO)Cl(PPh3)2(NC5H4COOEt-4) (1b), and of the pyrenyl complexes (1-Pyr-CHCH)Ru(CO)Cl(PiPr3)2 (3c) and (1-Pyr-CHCH)Ru(CO)Cl(PPh3)3 (3a-P) have been established by X-ray crystallography. All vinyl complexes undergo a one-electron oxidation at fairly low potentials and a second oxidation at more positive potentials. Anodic half-wave or peak potentials show a progressive shift to lower values as π-conjugation within the vinyl ligand increases. Carbonyl band shifts of the metal-bonded CO ligand upon monooxidation are significantly smaller than is expected of a metal-centered oxidation process and are further diminished as the vinyl CHCH entity is incorporated into a more extended π-system. ESR spectra of the electrogenerated radical cations display negligible g-value anisotropies and small deviations of the average g-value from that of the free electron. The vinyl ligands thus strongly contribute to or even dominate the anodic oxidation processes. This renders them a class of truly “non-innocent” ligands in organometallic ruthenium chemistry. Experimental findings are fully supported by quantum chemical calculations: The contribution of the vinyl ligand to the HOMO increases from 46% (Ru-vinyl delocalized) to 84% (vinyl dominated) as R changes from nbutyl to 1-pyrenyl

    Ancillary Ligand Control of Electronic Structure in o-Benzoquinonediimine-Ruthenium Complex Redox Series: Structures, Electron Paramagnetic Resonance (EPR), and Ultraviolet−Visible−Near-Infrared (UV-vis-NIR) Spectroelectrochemistry

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    The compounds Ru­(acac)<sub>2</sub>(Q) (<b>1</b>), [Ru­(bpy)<sub>2</sub>(Q)]­(ClO<sub>4</sub>)<sub>2</sub> ([<b>2</b>]­(ClO<sub>4</sub>)<sub>2</sub>), and [Ru­(pap)<sub>2</sub>(Q)]­PF<sub>6</sub> ([<b>3</b>]­PF<sub>6</sub>), containing Q = <i>N,N</i>′-diphenyl-<i>o</i>-benzoquinonediimine and donating 2,4-pentanedionate ligands (acac<sup>–</sup>), π-accepting 2,2<sup>/</sup>-bipyridine (bpy), or strongly <i>π-</i>accepting 2-phenylazopyridine (pap) were prepared and structurally identified. The electronic structures of the complexes and several accessible oxidized and reduced forms were studied experimentally (electrochemistry, magnetic resonance, ultraviolet-visible-near-infrared (UV-vis-NIR) spectroelectrochemistry) and computationally (DFT/TD-DFT) to reveal significantly variable electron transfer behavior and charge distribution. While the redox system <b>1</b><sup>+</sup>–<b>1</b><sup>–</sup> prefers trivalent ruthenium with corresponding oxidation states Q<sup>0</sup>–Q<sup>2–</sup> of the noninnocent ligand, the series <b>2</b><sup>2+</sup>–<b>2</b><sup>0</sup> and <b>3</b><sup>2+</sup>–<b>3</b><sup>–</sup> retain Ru<sup>II</sup>. The bpy and pap co-ligands are not only spectators but can also be reduced prior to a second reduction of Q. The present study with new experimental and computational evidence on the influence of co-ligands on the metal is complementary to a report on the substituent effects in <i>o</i>-quinonediimine ligands [Kalinina et al., <i>Inorg. Chem</i>. <b>2008</b>, <i>47</i>, 10110] and to the discussion of the most appropriate oxidation state formulation Ru<sup>II</sup>(Q<sup>0</sup>) or Ru<sup>III</sup>(Q<sup>• –</sup>)

    Ancillary Ligand Control of Electronic Structure in o-Benzoquinonediimine-Ruthenium Complex Redox Series: Structures, Electron Paramagnetic Resonance (EPR), and Ultraviolet−Visible−Near-Infrared (UV-vis-NIR) Spectroelectrochemistry

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    The compounds Ru­(acac)<sub>2</sub>(Q) (<b>1</b>), [Ru­(bpy)<sub>2</sub>(Q)]­(ClO<sub>4</sub>)<sub>2</sub> ([<b>2</b>]­(ClO<sub>4</sub>)<sub>2</sub>), and [Ru­(pap)<sub>2</sub>(Q)]­PF<sub>6</sub> ([<b>3</b>]­PF<sub>6</sub>), containing Q = <i>N,N</i>′-diphenyl-<i>o</i>-benzoquinonediimine and donating 2,4-pentanedionate ligands (acac<sup>–</sup>), π-accepting 2,2<sup>/</sup>-bipyridine (bpy), or strongly <i>π-</i>accepting 2-phenylazopyridine (pap) were prepared and structurally identified. The electronic structures of the complexes and several accessible oxidized and reduced forms were studied experimentally (electrochemistry, magnetic resonance, ultraviolet-visible-near-infrared (UV-vis-NIR) spectroelectrochemistry) and computationally (DFT/TD-DFT) to reveal significantly variable electron transfer behavior and charge distribution. While the redox system <b>1</b><sup>+</sup>–<b>1</b><sup>–</sup> prefers trivalent ruthenium with corresponding oxidation states Q<sup>0</sup>–Q<sup>2–</sup> of the noninnocent ligand, the series <b>2</b><sup>2+</sup>–<b>2</b><sup>0</sup> and <b>3</b><sup>2+</sup>–<b>3</b><sup>–</sup> retain Ru<sup>II</sup>. The bpy and pap co-ligands are not only spectators but can also be reduced prior to a second reduction of Q. The present study with new experimental and computational evidence on the influence of co-ligands on the metal is complementary to a report on the substituent effects in <i>o</i>-quinonediimine ligands [Kalinina et al., <i>Inorg. Chem</i>. <b>2008</b>, <i>47</i>, 10110] and to the discussion of the most appropriate oxidation state formulation Ru<sup>II</sup>(Q<sup>0</sup>) or Ru<sup>III</sup>(Q<sup>• –</sup>)
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