14,712 research outputs found

    Dynamic Resonance Effects in the Statistical Distributions of Asteroids and Comets

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    Some principles in the distribution of Centaurs and the "Scattered Disk" objects, as well as the Kuiper belt objects for its semi-major axes, eccentricities and inclinations of the orbits have been investigated. It has been established, that more than a half from them move on the resonant orbits and that is what has been predicted earlier. The divergence of the maximum in the observable distribution of the objects of the Kuiper belt for the semi-major axes with an exact orbital resonance has been interpreted.Comment: 7 pages, 5 figures, 1 table. International Conference "100 years since Tunguska phenomenon: Past, present and future", (June 26-28, 2008. Russia, Moscow), International Conference "Modern problems of astronomy" (August 12-18, 2007, Ukraine, Odessa

    Mobile obstacles accelerates and inhibits the bundle formation in two-patch colloidal particle

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    Aggregation of protein into bundles is responsible for many neurodegenerative diseases. In this work, we show how two-patch colloidal particles self assemble into chains and a sudden transition to bundles takes place by tuning the patch size and solvent condition. We study the kinetics of formation of chains, bundles and network like structures using Patchy Brownian cluster dynamics. We also analyse the ways to inhibit and accelerate the formation of these bundles. We show that in presence of inert immobile obstacles, the kinetics of formation of bundles slows down. Whereas, in presence of mobile aggregating particles which exhibit inter-particle attraction and intra-particle repulsion, the kinetics of bundle formation accelerates slightly. We also show that if we introduce mobile obstacles which exhibit intra-particle attraction and inter-particle hard sphere repulsion, the kinetics of formation of bundles is inhibited. This is similar to the inhibitory effect of peptide P4 on the formation of insulin fibres. We are providing a model of mobile obstacles undergoing directional interactions to inhibit the formation of bundles

    Zirconia based nucleic acid sensor for Mycobacterium tuberculosis detection

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    Nanostructured zirconium oxide (ZrO2) film (particle size ∼ 35 nm), electrochemically deposited onto gold(Au) surface, has been used to immobilize 21-mer oligonucleotide probe (ssDNA) specific to Mycobacterium tuberculosis by utilizing affinity between oxygen atom of phosphoric group and zirconium to fabricate DNA biosensor. This DNA-ZrO2/Au bioelectrode, characterized using x-ray diffraction, Fourier transform infrared spectroscopy, cyclic voltammetry, and scanning electron microscopy techniques, can be used for early and rapid diagnosis of M. tuberculosis with detection limit of 0.065 ng/μL within 60s

    Conformal GaP layers on Si wire arrays for solar energy applications

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    We report conformal, epitaxial growth of GaP layers on arrays of Si microwires. Silicon wires grown using chlorosilane chemical vapor deposition were coated with GaP grown by metal-organic chemical vapor deposition. The crystalline quality of conformal, epitaxial GaP/Si wire arrays was assessed by transmission electron microscopy and x-ray diffraction. Hall measurements and photoluminescence show p- and n-type doping with high electron mobility and bright optical emission. GaP pn homojunction diodes on planar reference samples show photovoltaic response with an open circuit voltage of 660 mV

    Analysis of acoustic emission during the melting of embedded indium particles in an aluminum matrix: a study of plastic strain accommodation during phase transformation

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    Acoustic emission is used here to study melting and solidification of embedded indium particles in the size range of 0.2 to 3 um in diameter and to show that dislocation generation occurs in the aluminum matrix to accommodate a 2.5% volume change. The volume averaged acoustic energy produced by indium particle melting is similar to that reported for bainite formation upon continuous cooling. A mechanism of prismatic loop generation is proposed to accommodate the volume change and an upper limit to the geometrically necessary increase in dislocation density is calculated as 4.1 x 10^9 cm^-2 for the Al-17In alloy. Thermomechanical processing is also used to change the size and distribution of the indium particles within the aluminum matrix. Dislocation generation with accompanied acoustic emission occurs when the melting indium particles are associated with grain boundaries or upon solidification where the solid-liquid interfaces act as free surfaces to facilitate dislocation generation. Acoustic emission is not observed for indium particles that require super heating and exhibit elevated melting temperatures. The acoustic emission work corroborates previously proposed relaxation mechanisms from prior internal friction studies and that the superheat observed for melting of these micron-sized particles is a result of matrix constraint.Comment: Presented at "Atomistic Effects in Migrating Interphase Interfaces - Recent Progress and Future Study" TMS 201

    Sudden Death and Left Ventricular Involvement in Arrhythmogenic Cardiomyopathy

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    BACKGROUND: Arrhythmogenic cardiomyopathy (ACM) is an inherited heart muscle disorder characterized by myocardial fibrofatty replacement and an increased risk of sudden cardiac death (SCD). Originally described as a right ventricular disease, ACM is increasingly recognized as a biventricular entity. We evaluated pathological, genetic, and clinical associations in a large SCD cohort. METHODS: We investigated 5205 consecutive cases of SCD referred to a national cardiac pathology center between 1994 and 2018. Hearts and tissue blocks were examined by expert cardiac pathologists. After comprehensive histological evaluation, 202 cases (4%) were diagnosed with ACM. Of these, 15 (7%) were diagnosed antemortem with dilated cardiomyopathy (n=8) or ACM (n=7). Previous symptoms, medical history, circumstances of death, and participation in competitive sport were recorded. Postmortem genetic testing was undertaken in 24 of 202 (12%). Rare genetic variants were classified according to American College of Medical Genetics and Genomics criteria. RESULTS: Of 202 ACM decedents (35.4±13.2 years; 82% male), no previous cardiac symptoms were reported in 157 (78%). Forty-one decedents (41/202; 20%) had been participants in competitive sport. The adjusted odds of dying during physical exertion were higher in men than in women (odds ratio, 4.58; 95% CI, 1.54-13.68; P=0.006) and in competitive athletes in comparison with nonathletes (odds ratio, 16.62; 95% CI, 5.39-51.24; P<0.001). None of the decedents with an antemortem diagnosis of dilated cardiomyopathy fulfilled definite 2010 Task Force criteria. The macroscopic appearance of the heart was normal in 40 of 202 (20%) cases. There was left ventricular histopathologic involvement in 176 of 202 (87%). Isolated right ventricular disease was seen in 13%, isolated left ventricular disease in 17%, and biventricular involvement in 70%. Among whole hearts, the most common areas of fibrofatty infiltration were the left ventricular posterobasal (68%) and anterolateral walls (58%). Postmortem genetic testing yielded pathogenic variants in ACM-related genes in 6 of 24 (25%) decedents. CONCLUSIONS: SCD attributable to ACM affects men predominantly, most commonly occurring during exertion in athletic individuals in the absence of previous reported cardiac symptoms. Left ventricular involvement is observed in the vast majority of SCD cases diagnosed with ACM at autopsy. Current Task Force criteria may fail to diagnose biventricular ACM before death
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