110 research outputs found

    Random-phase approximation and its applications in computational chemistry and materials science

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    The random-phase approximation (RPA) as an approach for computing the electronic correlation energy is reviewed. After a brief account of its basic concept and historical development, the paper is devoted to the theoretical formulations of RPA, and its applications to realistic systems. With several illustrating applications, we discuss the implications of RPA for computational chemistry and materials science. The computational cost of RPA is also addressed which is critical for its widespread use in future applications. In addition, current correction schemes going beyond RPA and directions of further development will be discussed.Comment: 25 pages, 11 figures, published online in J. Mater. Sci. (2012

    Half-solitons in a polariton quantum fluid behave like magnetic monopoles

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    Monopoles are magnetic charges, point-like sources of magnetic field. Contrary to electric charges they are absent in Maxwell's equations and have never been observed as fundamental particles. Quantum fluids such as spinor Bose-Einstein condensates have been predicted to show monopoles in the form of excitations combining phase and spin topologies. Thanks to its unique spin structure and the direct optical control of the fluid wavefunction, an ideal system to experimentally explore this phenomenon is a condensate of exciton-polaritons in a semiconductor microcavity. We use this system to create half-solitons, non-linear excitations with mixed spin-phase geometry. By tracking their trajectory, we demonstrate that half-solitons behave as monopoles, magnetic charges accelerated along an effective magnetic field present in the microcavity. The field-induced spatial separation of half-solitons of opposite charges opens the way to the generation of magnetic currents in a quantum fluid.Comment: 19 pages, includes Supplmentary Informatio

    Antiinflammatory Therapy with Canakinumab for Atherosclerotic Disease

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    Background: Experimental and clinical data suggest that reducing inflammation without affecting lipid levels may reduce the risk of cardiovascular disease. Yet, the inflammatory hypothesis of atherothrombosis has remained unproved. Methods: We conducted a randomized, double-blind trial of canakinumab, a therapeutic monoclonal antibody targeting interleukin-1β, involving 10,061 patients with previous myocardial infarction and a high-sensitivity C-reactive protein level of 2 mg or more per liter. The trial compared three doses of canakinumab (50 mg, 150 mg, and 300 mg, administered subcutaneously every 3 months) with placebo. The primary efficacy end point was nonfatal myocardial infarction, nonfatal stroke, or cardiovascular death. RESULTS: At 48 months, the median reduction from baseline in the high-sensitivity C-reactive protein level was 26 percentage points greater in the group that received the 50-mg dose of canakinumab, 37 percentage points greater in the 150-mg group, and 41 percentage points greater in the 300-mg group than in the placebo group. Canakinumab did not reduce lipid levels from baseline. At a median follow-up of 3.7 years, the incidence rate for the primary end point was 4.50 events per 100 person-years in the placebo group, 4.11 events per 100 person-years in the 50-mg group, 3.86 events per 100 person-years in the 150-mg group, and 3.90 events per 100 person-years in the 300-mg group. The hazard ratios as compared with placebo were as follows: in the 50-mg group, 0.93 (95% confidence interval [CI], 0.80 to 1.07; P = 0.30); in the 150-mg group, 0.85 (95% CI, 0.74 to 0.98; P = 0.021); and in the 300-mg group, 0.86 (95% CI, 0.75 to 0.99; P = 0.031). The 150-mg dose, but not the other doses, met the prespecified multiplicity-adjusted threshold for statistical significance for the primary end point and the secondary end point that additionally included hospitalization for unstable angina that led to urgent revascularization (hazard ratio vs. placebo, 0.83; 95% CI, 0.73 to 0.95; P = 0.005). Canakinumab was associated with a higher incidence of fatal infection than was placebo. There was no significant difference in all-cause mortality (hazard ratio for all canakinumab doses vs. placebo, 0.94; 95% CI, 0.83 to 1.06; P = 0.31). Conclusions: Antiinflammatory therapy targeting the interleukin-1β innate immunity pathway with canakinumab at a dose of 150 mg every 3 months led to a significantly lower rate of recurrent cardiovascular events than placebo, independent of lipid-level lowering. (Funded by Novartis; CANTOS ClinicalTrials.gov number, NCT01327846.

    Multi-time equations, classical and quantum

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    Molecular characterization of a new arcelin-5 gene

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    Arcelins are insecticidal proteins found in some wild accessions of the common bean, Phaseolus vulgaris. They are grouped in six allelic variants and arcelin-5 is the variant with the highest inhibitory effect on the development of Zabrotes subfasciatus larvae. Characterization of the protein and its genes resulted in the identification of three polypeptides and the isolation of two genes that encode the Arc5a and Arc5b polypeptides. Here we describe a new gene, Arc5-III. The protein it encodes has 81% amino acid identity with the derived amino acid sequences of Arc5-I and Arc5-II. The Arc5-III gene is highly expressed in developing seeds and at a much lower level in roots. Data obtained by a combination of two-dimensional gel electrophoresis, protein sequencing and MALDI-TOF mass spectrometry analysis support the conclusion that Arc5-III encodes a polypeptide present in Arc5c band, Using ion-exchange chromatography, three fractions containing arcelin-5 polypeptides were eluted by increasing the salt concentration. The three fractions contain various amounts of the three arc-5 polypeptides and inhibit the growth of Zabrotes subfasciatus larvae differentially, suggesting differences in insecticidal activity among the arcelin-5 isoforms. (C) 2000 Elsevier Science B.V. All rights reserved.149041671879

    Pollution Prevention Strategies for College Campuses: A Case Study at the University of Michigan

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    http://deepblue.lib.umich.edu/bitstream/2027.42/192150/1/Table of Contents.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/192150/2/Section I.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/192150/3/Section II.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/192150/4/Section III.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/192150/5/Appendix.pdfDescription of Table of Contents.pdf : Table of ContentsDescription of Section I.pdf : Section 1Description of Section II.pdf : Section 2Description of Section III.pdf : Section 3Description of Appendix.pdf : AppendixSEL
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