435 research outputs found
Idealized Slab Plasma approach for the study of Warm Dense Matter
Recently, warm dense matter (WDM) has emerged as an interdisciplinary field
that draws increasing interest in plasma physics, condensed matter physics,
high pressure science, astrophysics, inertial confinement fusion, as well as
materials science under extreme conditions. To allow the study of well-defined
WDM states, we have introduced the concept of idealized-slab plasmas that can
be realized in the laboratory via (i) the isochoric heating of a solid and (ii)
the propagation of a shock wave in a solid. The application of this concept
provides new means for probing the dynamic conductivity, equation of state,
ionization and opacity. These approaches are presented here using results
derived from first-principles (density-functional type) theory, Thomas-Fermi
type theory, and numerical simulations.Comment: 37 pages, 21 figures, available, pdf file only. To appear in: Laser
and Particle beams. To appear more or less in this form in Laser and Particle
beam
Development of a reverse transcription loop-mediated isothermal amplification (RT-LAMP) method to detect living pinewood nematode, Bursaphelenchus xylophilus, in wood
Anomalous material-dependent transport of focused, laser-driven proton beams.
Intense lasers can accelerate protons in sufficient numbers and energy that the resulting beam can heat materials to exotic warm (10 s of eV temperature) states. Here we show with experimental data that a laser-driven proton beam focused onto a target heated it in a localized spot with size strongly dependent upon material and as small as 35 μm radius. Simulations indicate that cold stopping power values cannot model the intense proton beam transport in solid targets well enough to match the large differences observed. In the experiment a 74 J, 670 fs laser drove a focusing proton beam that transported through different thicknesses of solid Mylar, Al, Cu or Au, eventually heating a rear, thin, Au witness layer. The XUV emission seen from the rear of the Au indicated a clear dependence of proton beam transport upon atomic number, Z, of the transport layer: a larger and brighter emission spot was measured after proton transport through the lower Z foils even with equal mass density for supposed equivalent proton stopping range. Beam transport dynamics pertaining to the observed heated spot were investigated numerically with a particle-in-cell (PIC) code. In simulations protons moving through an Al transport layer result in higher Au temperature responsible for higher Au radiant emittance compared to a Cu transport case. The inferred finding that proton stopping varies with temperature in different materials, considerably changing the beam heating profile, can guide applications seeking to controllably heat targets with intense proton beams
X-ray Astronomy in the Laboratory with a Miniature Compact Object Produced by Laser-Driven Implosion
Laboratory spectroscopy of non-thermal equilibrium plasmas photoionized by
intense radiation is a key to understanding compact objects, such as black
holes, based on astronomical observations. This paper describes an experiment
to study photoionizing plasmas in laboratory under well-defined and genuine
conditions. Photoionized plasma is here generated using a 0.5-keV Planckian
x-ray source created by means of a laser-driven implosion. The measured x-ray
spectrum from the photoionized silicon plasma resembles those observed from the
binary stars Cygnus X-3 and Vela X-1 with the Chandra x-ray satellite. This
demonstrates that an extreme radiation field was produced in the laboratory,
however, the theoretical interpretation of the laboratory spectrum
significantly contradicts the generally accepted explanations in x-ray
astronomy. This model experiment offers a novel test bed for validation and
verification of computational codes used in x-ray astronomy.Comment: 5 pages, 4 figures are included. This is the original submitted
version of the manuscript to be published in Nature Physic
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One- and two-dimensional density and temperature measurements of an argon-neon Z-pinch plasma at stagnation
In order to benchmark and improve current 2D radiation magnetohydrodynamic (MHD) models of Z-pinch plasmas, we have performed experiments which characterize the plasma -conditions at stagnation. In the experiments the SATURN pulsed power facility at Sandia National Laboratory was used to create an imploding -Ar-Ne plasma. An absolutely calibrated, high resolution space- and time- resolving Johann crystal spectrometer was used to infer the electron temperature Te from the slope of the hydrogenlike Ne free-bound continuum, and the ion density ni from the Stark broadening of the Ar heliunlike Rydberg series. 2D electron temperature profiles of the plasma are obtained from a set of imaging crystals also focused on the Ne free-bound continuum. We shot two types of gas nozzles in the experiment, annular and uniform fill which varies the amount of mass in the plasma. 2D local thermodynamic equilibrium (LTE) and non-LTE MM models predict a radiating region denser and cooler than measured
TRH: Pathophysiologic and clinical implications
Thyrotropin releasing hormone is thought to be a tonic stimulator of the pituitary TSH secretion regulating the setpoint of the thyrotrophs to the suppressive effect of thyroid hormones. The peptide stimulates the release of normal and elevated prolactin. ACTH and GH may increase in response to exogenous TRH in pituitary ACTH and GH hypersecretion syndromes and in some extrapituitary diseases.
The pathophysiological implications of extrahypothalamic TRH in humans are essentially unknown.
The TSH response to TRH is nowadays widely used as a diganostic amplifier in thyroid diseases being suppressed in borderline and overt hyperthyroid states and increased in primary thyroid failure. In hypothyroid states of hypothalamic origin, TSH increases in response to exogenous TRH often with a delayed and/or exaggerated time course.
But in patients with pituitary tumors and suprasellar extension TSH may also respond to TRH despite secondary hypothyroidism. This TSH increase may indicate a suprasellar cause for the secondary hypothyroidism, probably due to portal vessel occlusion. The TSH released in these cases is shown to be biologically inactive
Molecular evidence of Ebola Reston virus infection in Philippine bats
Background: In 2008-09, evidence of Reston ebolavirus (RESTV) infection was found in domestic pigs and pig workers in the Philippines. With species of bats having been shown to be the cryptic reservoir of filoviruses elsewhere, the Philippine government, in conjunction with the Food and Agriculture Organization of the United Nations, assembled a multi-disciplinary and multi-institutional team to investigate Philippine bats as the possible reservoir of RESTV. Methods: The team undertook surveillance of bat populations at multiple locations during 2010 using both serology and molecular assays. Results: A total of 464 bats from 21 species were sampled. We found both molecular and serologic evidence of RESTV infection in multiple bat species. RNA was detected with quantitative PCR (qPCR) in oropharyngeal swabs taken from Miniopterus schreibersii, with three samples yielding a product on conventional hemi-nested PCR whose sequences differed from a Philippine pig isolate by a single nucleotide. Uncorroborated qPCR detections may indicate RESTV nucleic acid in several additional bat species (M. australis, C. brachyotis and Ch. plicata). We also detected anti-RESTV antibodies in three bats (Acerodon jubatus) using both Western blot and ELISA. Conclusions: The findings suggest that ebolavirus infection is taxonomically widespread in Philippine bats, but the evident low prevalence and low viral load warrants expanded surveillance to elaborate the findings, and more broadly, to determine the taxonomic and geographic occurrence of ebolaviruses in bats in the region. © 2015 Jayme et al
Anatase crystals of unusual habit in quartz veins from the Diamantina region (Espinhaço Range, Minas Gerais)
GLIDA: GPCR—ligand database for chemical genomics drug discovery—database and tools update
G-protein coupled receptors (GPCRs) represent one of the most important families of drug targets in pharmaceutical development. GLIDA is a public GPCR-related Chemical Genomics database that is primarily focused on the integration of information between GPCRs and their ligands. It provides interaction data between GPCRs and their ligands, along with chemical information on the ligands, as well as biological information regarding GPCRs. These data are connected with each other in a relational database, allowing users in the field of Chemical Genomics research to easily retrieve such information from either biological or chemical starting points. GLIDA includes a variety of similarity search functions for the GPCRs and for their ligands. Thus, GLIDA can provide correlation maps linking the searched homologous GPCRs (or ligands) with their ligands (or GPCRs). By analyzing the correlation patterns between GPCRs and ligands, we can gain more detailed knowledge about their conserved molecular recognition patterns and improve drug design efforts by focusing on inferred candidates for GPCR-specific drugs. This article provides a summary of the GLIDA database and user facilities, and describes recent improvements to database design, data contents, ligand classification programs, similarity search options and graphical interfaces. GLIDA is publicly available at http://pharminfo.pharm.kyoto-u.ac.jp/services/glida/. We hope that it will prove very useful for Chemical Genomics research and GPCR-related drug discovery
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