1,305 research outputs found

    Quasilocal energy and thermodynamic equilibrium conditions

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    Equilibrium thermodynamic laws are typically applied to horizons in general relativity without stating the conditions that bring them into equilibrium. We fill this gap by applying a new thermodynamic interpretation to a generalized Raychaudhuri equation for a worldsheet orthogonal to a closed spacelike 2-surface, the "screen", which encompasses a system of arbitrary size in nonequilibrium with its surroundings in general. In the case of spherical symmetry this enables us to identify quasilocal thermodynamic potentials directly related to standard quasilocal energy definitions. Quasilocal thermodynamic equilibrium is defined by minimizing the mean extrinsic curvature of the screen. Moreover, without any direct reference to surface gravity, we find that the system comes into quasilocal thermodynamic equilibrium when the screen is located at a generalized apparent horizon. Examples of the Schwarzschild, Friedmann-Lema\^itre and Lema\^itre-Tolman geometries are investigated and compared. Conditions for the quasilocal thermodynamic and hydrodynamic equilibrium states to coincide are also discussed, and a quasilocal virial relation is suggested as a potential application of this approach.Comment: 27 pages. v2 small typos fixed, matches published versio

    A variation in the formation of the median nerve: communicating branch between the musculocutaneous and median nerves in man

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    We encountered variation in the formation of the median nerve in a 66-year-old male cadaver during dissection of the upper extremity of 20 adult cadavers. The dissections were made at the Department of Cellular Biology and Anatomy, Louisiana State University Medical Center. The median nerve was formed by fusion of four branches, three of them coming from the lateral cord and one from the medial cord. The normal radix from the lateral cord followed a very close oblique course over the axillary artery. The first unusual radix to the median nerve had an anastomoses from the musculocutaneous nerve to the median nerve in the proximal part of the left arm. The second unusual radix also came from the musculocutaneous nerve after it had pierced the coracobrachialis muscle and then joined with the median nerve. These kinds of variations are vulnerable to damage in radical neck dissection and other surgical operations of the axilla and upper arm. The communicating branch can be explained on the basis of its embryologic development and also ought to be distinguished from the other nerve variations in the upper extremity. The aim of this paper is to provide additional information for the classification of previously found communications between the musculocutaneous and median nerves

    The anastomotic artery connecting the axillary or brachial artery to one of the forearm arteries

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    A vessel connecting the axillary or brachial artery to one of the forearm arteries was found in a 65 year old male cadaver, during the gross anatomy dissection of the upper extremity of 20 adult cadavers at the Department of Cellular Biology and Anatomy, Louisiana State University Medical Center. The right radial artery originated from the brachial artery nearly at the usual level and was connected to the axillary or brachial artery by a long slender anastomotic artery (vasa aberrantia). The anastomotic artery coursed under the medial side of the biceps muscle between the median and musculocutaneous nerves, and gave off two muscular branches to the biceps muscle. The anastomotic artery coursed between the median and musculocutaneous nerves in the arm, it passed to the forearm under the bicipital aponeurosis and connected the main radial artery on the radial side of the forearm. The anastomotic artery can be explained on the basis of its embryologic development and also ought to be distinguished from the other common arterial variations in the upper extremity

    Full-field eigenstrain reconstruction for the investigation of residual stresses in finite length weldments

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    The reconstruction of welding residual stresses has been performed based on the assumption of continuous processing conditions, owing to the limitations of reconstruction methods. This assumption prevents the attainment of a comprehensive understanding of mechanical deformations in the entire weld zone. The voxel-based eigenstrain (inherent strain) reconstruction method emerges as an appropriate approach for the full-field reconstruction of residual stresses in finite length weldments without such assumption. The innovative reconstruction capability of this advanced method is presented in this study, aiming to comprehend all components of residual stresses and eigenstrains in finite length weldments with discontinuous processing properties using only a single component of experimental data belonging to a limited portion of the specimen. Numerical experiments were conducted to develop the tools. These tools were validated using a case study employing experimental data obtained through contact profilometry measurements from the surface of discharge machine cutting (minimally disturbing cutting) in a bead-on-plate weldment of Inconel alloy 740H designed for ultra-supercritical power generation. The reconstructed two components of normal residual stresses that do not align with the available experimental data were validated by independent neutron diffraction strain scanning quantifications. Furthermore, the reconstruction of residual stresses in the intact component prior to cutting was carried out using the eigenstrains associated with the post-cut state of the weldment

    L-Lysine Imprinted Nanoparticles for Antibody Biorecognition

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    The aim of this study was to prepare L-lysine-imprinted poly(HEMA-MAAsp) nanoparticles which can be used for the adsorption of IgG from aqueous solutions. L-lysine was complexed with MAAsp and Llysine- imprinted poly(HEMA-MAAsp) nanoparticles were synthesized by miniemulsion polymerization. Also, non-imprinted nanoparticles were synthesized without L-lysine for control purpose. L-lysine-imprinted poly(HEMA-MAAsp) nanoparticles were characterized by means of elemental analysis, Fourier transform infrared spectroscopy (FTIR) and transmission electron microscopy (TEM). When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/3500

    Magnetic Nanoparticles for Plasmid DNA Adsorption via Hydrophobic Interaction

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    This study aims the preparation of magnetic poly(2-hydroxyethylmethacrylate-N-methacryloyl-Lphenylalanine), [poly(HEMA-MAPA)] nanoparticles for plasmid DNA separation on the basis of hydrophobic interactions. Magnetic nanoparticles will be produced emulsion polymerization of 2- hydroxyethylmethacrylate (HEMA) and N-methacryloyl-L-phenylalanine (MAPA) monomers. Nanosized particles including hydrophobic groups stemmed from polymerizable derivative of phenylalanine aminoacid were evaluated to offer surface area that is enough for the higher capacity DNA purification than commercial micronsized sorbents for DNA purification. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/3494

    Preparation of Ion Imprinted SPR Sensor for Real-Time Detection of Silver(I) Ion from Aqueous Solution

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    The aim of the submitted study is to develop molecular imprinting based surface plasmon resonance (SPR) sensor for real-time silver ion detection. For this purpose polymeric nanofilm layer on the gold SPR chip surface was prepared via UV polymerization of acrylic acid at 395 nm for 30 minutes. N-methacryloyl- L cysteine used as the functional monomer to recognize the silver(I) ions from the aqueous solutions and methylene bisacrylamide used as the crosslinker for obtaining structural rigidity of the formed cavities. Silver(I) solutions with different concentrations were applied to SPR system to investigate the efficiency of the imprinted SPR sensor in real time. For the control experiments, non-imprinted SPR sensor was also prepared as described above without addition of template “silver(I) ions”. Prepared SPR sensors were characterized with atomic force microscopy (AFM). In order to show the selectivity of the silver(I) imprinted SPR sensor, competitive adsorption of Cu(II), Pb(II), Ni(II) ions was investigated. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/3489

    Measurement and physical interpretation of the mean motion of turbulent density patterns detected by the BES system on MAST

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    The mean motion of turbulent patterns detected by a two-dimensional (2D) beam emission spectroscopy (BES) diagnostic on the Mega Amp Spherical Tokamak (MAST) is determined using a cross-correlation time delay (CCTD) method. Statistical reliability of the method is studied by means of synthetic data analysis. The experimental measurements on MAST indicate that the apparent mean poloidal motion of the turbulent density patterns in the lab frame arises because the longest correlation direction of the patterns (parallel to the local background magnetic fields) is not parallel to the direction of the fastest mean plasma flows (usually toroidal when strong neutral beam injection is present). The experimental measurements are consistent with the mean motion of plasma being toroidal. The sum of all other contributions (mean poloidal plasma flow, phase velocity of the density patterns in the plasma frame, non-linear effects, etc.) to the apparent mean poloidal velocity of the density patterns is found to be negligible. These results hold in all investigated L-mode, H-mode and internal transport barrier (ITB) discharges. The one exception is a high-poloidal-beta (the ratio of the plasma pressure to the poloidal magnetic field energy density) discharge, where a large magnetic island exists. In this case BES detects very little motion. This effect is currently theoretically unexplained.Comment: 28 pages, 15 figures, submitted to PPC

    Changes in heart rate variability and QT variability during the first trimester of pregnancy

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    The risk of new-onset arrhythmia during pregnancy is high, presumably relating to changes in both haemodynamic and cardiac autonomic function. The ability to non-invasively assess an individual's risk of developing arrhythmia during pregnancy would therefore be clinically significant. We aimed to quantify electrocardiographic temporal characteristics during the first trimester of pregnancy and to compare these with non-pregnant controls.Ninety-nine pregnant women and sixty-three non-pregnant women underwent non-invasive cardiovascular and haemodynamic assessment during a protocol consisting of various physiological states (postural manoeurvres, light exercise and metronomic breathing). Variables measured included stroke volume, cardiac output, heart rate, heart rate variability, QT and QT variability and QTVI (a measure of the variability of QT relative to that of RR).Heart rate (p < 0.0005, p < 0.0005, p < 0.0005) and cardiac output (p = 0.043, p < 0.0005, p < 0.0005) were greater in pregnant women in all physiological states (respectively for the supine position, light exercise and metronomic breathing state), whilst stroke volume was lower in pregnancy only during the supine position (p < 0.0005). QTe (Q wave onset to T wave end) and QTa (T wave apex) were significantly shortened (p < 0.05) and QTeVI and QTaVI were increased in pregnancy in all physiological states (p < 0.0005). QT variability (p < 0.002) was greater in pregnant women during the supine position, whilst heart rate variability was reduced in pregnancy in all states (p < 0.0005).Early pregnancy is associated with substantial changes in heart rate variability, reflecting a reduction in parasympathetic tone and an increase in sympathetic activity. QTVI shifted to a less favourable value, reflecting a greater than normal amount of QT variability. QTVI appears to be a useful method for quantifying changes in QT variability relative to RR (or heart rate) variability, being sensitive not only to physiological state but also to gestational age. We support the use of non-invasive markers of cardiac electrical variability to evaluate the risk of arrhythmic events in pregnancy, and we recommend the use of multiple physiological states during the assessment protocol
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