833 research outputs found
Effects of the Nearest-Neighbour Coulomb Interactions on the Ground State of the Periodic Anderson Model
The magnetic and non-magnetic ground states of the periodic Anderson model
with Coulomb interaction between -electrons on the nearest-neighbour(NN)
sites are investigated using a variational method, which gives exact
calculation of the expectation values in the limit of infinite dimensions. It
is shown that for a critical value of NN Coulomb interactions the magnetic
ground state of the periodic Anderson model in the Kondo regime is unstable.
Factors in terms of the physical processes responsible for instability of the
magnetic ground state are also discussed. Our study indicates the importance of
the NN Coulomb interactions for correlated two band models.Comment: RevTeX, 6 pages, 5 figures, to appear in Phys. Rev.
Maternal mortality: a tertiary centre panic
Background: Maternal death has a serious implication on the family, society and nation. The preventable and avoidable factors have been noted in most of the maternal deaths and these can be reduced by effective and affordable actions. The objective of present study was to evaluate the causes of maternal mortality in a tertiary care hospital, assess its epidemiological aspects and suggest remedial measures to reduce the same.Methods: A retrospective study of all hospital records and death summaries of all maternal deaths over a period of 16 months from April 2015 to July 2016 was carried out and epidemiological factors and causes affecting maternal mortality were assessed.Results: A total of 100 maternal deaths occurred over a period of 15 months out of which unbooked and late referrals constituted 75.55 % of maternal deaths. Most maternal deaths occurred in the age group of 20–30 years, multiparous women (73%) and women from rural areas (71.%). Direct obstetric causes were responsible for 91 maternal deaths whereas 50 maternal deaths were due to indirect causes. Most common cause of death (41) was hemorrhage, followed by pregnancy-induced hypertension including eclampsia (15) and sepsis (21).Conclusions: Hemorrhage, sepsis and hypertension including eclampsia were seen as the direct major causes of death. There is a wide scope of improvement because a large proportion of the observed deaths are preventable
Thermal stress analysis in a functionally graded hollow elliptic-cylinder subjected to uniform temperature distribution
In this paper, an analytical method of a thermoelastic problem for a medium with functionally graded material properties is developed in a theoretical manner for the elliptic-cylindrical coordinate system under the assumption that the material properties except for Poisson’s ratio and density are assumed to vary arbitrarily with the exponential law in the radial direction. An attempt has been made to reconsider the fundamental system of equations for functionally graded solids in a two-dimensional state under thermal and mechanical loads. The general solution of displacement formulation is obtained by the introduction of appropriate transformation and carried out the analysis by taking into account the variation of inhomogeneity parameters. Furthermore, the aforementioned problem degenerated into the problem of the circular region by applying limiting conditions, and the results are validated. Numerical computations are carried out for ceramic-metal-based functionally graded material, in which zirconia is selected as ceramic and aluminium as metal and are represented graphically
Thermoelastic analysis of a nonhomogeneous hollow cylinder with internal heat generation
In the present paper, we have determined the heat conduction and thermal stresses of a hollow cylinder with inhomogeneous material properties and internal heat generation. All the material properties except Poisson’s ratio and density are assumed to be given by a simple power law in axial direction. We have obtained the solution of the two dimensional heat conduction equation in the transient state in terms of Bessel’s and trigonometric functions. The influence of inhomogeneity on the thermal and mechanical behavior is examined. Numerical computations are carried out for both homogeneous and nonhomogeneous cylinders and are represented graphically
Heat-shock protein 27 (HSP27, HSPB1) is synthetic lethal to cells with oncogenic activation of MET, EGFR and BRAF
Assignment of disulphide bridges in Par j 2.0101, a major allergen of Parietaria judaica pollen.
Par j 2.0101, a major allergen of the Parietaria judaica pollen, was expressed in E. coli, purified to homogeneity and fully characterised both at the structural and the functional level. The recombinant rPar j 2.0101 protein showed an allergenic activity in histamine release, skin prick tests and capacity to bind IgE, almost identical to that of the native allergens purified from aqueous pollen extract. The complete pattern of S-S bridges of rPar j 2.0101 was determined by enzymatic digestion with endoproteinase Lys-C followed by mass spectrometric analysis of the resulting peptide mixtures. The eight cysteines occurring in the allergenic protein were found to be paired into the following four disulphides: Cys35-Cys83, Cys45-Cys6O, Cys61-Cys106 and Cys81-Cys121. This structural information probes Par j 2.0101 to attain a 3-D fold consistent with that of the non-specific lipid transfer protein (ns-LTP) family and it represents an effective molecular basis to develop modified antigens by selective site-directed mutagenesis for immunotherapy
A novel AhR ligand, 2AI, protects the retina from environmental stress.
Various retinal degenerative diseases including dry and neovascular age-related macular degeneration (AMD), retinitis pigmentosa, and diabetic retinopathy are associated with the degeneration of the retinal pigmented epithelial (RPE) layer of the retina. This consequently results in the death of rod and cone photoreceptors that they support, structurally and functionally leading to legal or complete blindness. Therefore, developing therapeutic strategies to preserve cellular homeostasis in the RPE would be a favorable asset in the clinic. The aryl hydrocarbon receptor (AhR) is a conserved, environmental ligand-dependent, per ARNT-sim (PAS) domain containing bHLH transcription factor that mediates adaptive response to stress via its downstream transcriptional targets. Using in silico, in vitro and in vivo assays, we identified 2,2'-aminophenyl indole (2AI) as a potent synthetic ligand of AhR that protects RPE cells in vitro from lipid peroxidation cytotoxicity mediated by 4-hydroxynonenal (4HNE) as well as the retina in vivo from light-damage. Additionally, metabolic characterization of this molecule by LC-MS suggests that 2AI alters the lipid metabolism of RPE cells, enhancing the intracellular levels of palmitoleic acid. Finally, we show that, as a downstream effector of 2AI-mediated AhR activation, palmitoleic acid protects RPE cells from 4HNE-mediated stress, and light mediated retinal degeneration in mice
A tapered multi-gap multi-aperture pseudospark-sourced electron gun based X-band slow wave oscillator
The experimental study of a tapered, multi-gap, multi-aperture pseudospark-sourced electron gun based X-band plasma assisted slow wave oscillator is presented. The designed electron gun is based on the pseudospark discharge concept and has been used to generate a high current density and high energy electron beam simultaneously. The distribution of apertures has been arranged such that the field penetration potency inside the backspace of the hollow-cathode is different while passing through the tapered gap region. This leads to non-concurrent ignition of the discharge through all the channels which is, in general, quite challenging in the case of multi-aperture plasma cathode electron gun geometries. Multiple and successive hollow cathode phases are reported from this electron gun geometry, which have been confirmed using simulations. This geometry also has led to the achievement of ∼71% fill factor inside the slow wave oscillator for an electron beam of energy of 20 keV and a beam current density in the range of 115-190 A/cm2 at a working argon gas pressure of 18 Pa. The oscillator has generated broadband microwave output in the frequency range of 10-11.7 GHz with a peak power of ∼10 kW for ∼50 ns
Isolated Post-Traumatic Radial Head Dislocation, A Rare and Easily Missed Injury-A Case Report
Dislocation of the head of the radius may be either congenital, an isolated injury or more commonly part of a complex injury to the elbow such as the Monteggia fracturedislocation. Isolated traumatic radial head dislocation without associated injuries in children is a rare and easily missed condition. We report such a case in a 7-year-old boy without any associated injuries or co-morbid conditions.
Initially the diagnosis was missed, and 6 weeks later open reduction was performed with annular ligament reconstruction surgery. At the one-year follow up, the patient had returned to most normal activities, showing only slight terminal restriction of pronation. We discuss the injury mechanism and management for the Monteggia fracturedislocation and review the available literature
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