1,522 research outputs found

    Moving Stationary State of Exciton-Phonon Condensate in Cu2O

    Full text link
    We explore a simple theoretical model to describe the properties of Bose condensed para-excitons in Cu2O. Taking into account the exciton-phonon interaction and introducing a coherent phonon part of the moving condensate, we derive the dynamic equations for the exciton-phonon condensate. Within the Bose approximation for excitons, we discuss the conditions for the moving inhomogeneous condensate to appear in the crystal. We calculate the condensate wave function and energy and a collective excitation spectrum in the semiclassical approximation. The stability conditions of the moving condensate are analyzed by use of Landau arguments, and two critical velocities appear in the theory. Finally, we apply our model to describe the recently observed interference between two coherent exciton-phonon packets in Cu2O.Comment: 20 pages (LaTeX), one figure (.ps) incorporated by epsf. Submitted to Phys. Stat. Sol (B

    Selection of Generalized Two Plan System Using Minimum Angle Method

    Get PDF
    This paper presents a new procedure and tables for the selection of Generalized Two Plan system through minimum angle criteria involving producer’s and consumer’s quality levels. The approach of minimum angle method by considering the tangent of the angle between the lines joining the points (AQL, 1-α) and (LQL, β). Illustrations are also provided for ready-made selection of plan parameters

    Endovascular repair of type B aortic dissection: a study by computational fluid dynamics

    Get PDF
    Aortic dissection is a dangerous pathological condi-tion where blood intrudes into the layers of the arte-rial walls, creating an artificial channel (false lumen). In the absence of thrombosis or surgical intervention, blood will enter the false lumen through the proximal tear, and join the true lumen again through a distal tear. Rupture of the weakened outer wall will result in extremely high mortality rates. Type B thoracic aortic dissection (TAD), occurring along the de-scending aorta, can be repaired surgically by the de-ployment of an endovascular stent graft, concealing the proximal entry tear. Blood might still flow into the false lumen (FL) through the distal tear. The do-main of such flow should be minimized, as complete thrombosis of the FL is generally believed to be more beneficial for the patient. The dependence on the area ratios of the lumens and size of these tears is studied by computational fluid dynamics.published_or_final_versio

    The association of HBV core promoter double mutations (A1762T and G1764A) with viral load differs between HBeAg positive and anti-HBe positive individuals: A longitudinal analysis

    Get PDF
    Background/Aims: Although there have been a few reports regarding the effect of basal core promoter (BCP) double mutations (A1762T and G1764A) on hepatitis B viral loads, the association remains uncertain. We aim to determine the association after controlling for HBeAg - a strong confounding factor.Methods: We selected randomly 190 individuals from a Chinese cohort of 2258 subjects for cross-sectional analysis and 56 of the 190 for longitudinal analysis of viral loads.Results: In multivariable analysis of the cross-sectional data, BCP double mutations are significantly associated with lower viral loads in HBeAg positive subjects but no difference was found in anti-HBe positive subjects. Triple mutations at nucleotide (nt) 1753, 1762 and 1764 and mutations between nt 1809 and 1817, precore stop mutation (nt 1896) and genotype are not associated with viral loads in either HBeAg or anti-HBe positive subjects. Analysis of the longitudinal data yielded similar results to the cross-sectional data. Viral loads differ significantly between individuals infected with wild-type and BCP double mutations prior to HBeAg seroconversion but this difference is lost after seroconversion.Conclusions: BCP double mutations are associated with lower viral loads in HBeAg positive individuals but have no effect on the viral loads of anti-HBe positive individuals. (C) 2008 European Association for the Study of the Liver. Published by Elsevier B.V. All rights reserved

    Taxol synthesis

    Get PDF
    Being a complex diterpenoid, the potent anticancer drug, Taxol, requires complicated steps for its biosynthesis. In the present article, recent advances on Taxol biosynthesis pathway are reviewed, including many recently reported genes that regulate Taxol biosynthesis. To meet the urgent need of clinic and scientific research, besides Taxus supply, other approaches to obtain Taxol have also been discussed here.Keywords: biosynthesis pathway, cell culture, endophytic fungi, Taxol, Taxu

    Successful endovascular infrarenal aneurysm repair in a patient with situs inversus totalis

    Get PDF
    Situs inversus totalis is a rare autosomal recessive developmental anomaly. There are very few reports in the published literature of abdominal aortic aneurysm in patient with situs inversus totalis, all of whom underwent open aneurysm repair. This is the first case in the world's literature to describe a patient with situs inversus totalis who had a successful endovascular infrarenal aneurysm repair. Although endovascular infrarenal aneurysm repair should not be more challenging, the endovascular approach may decrease risk of potential errors because of unfamiliar anatomy. Technical considerations in performing endovascular procedures in patients with situs inversus totalis are discussed in this article. © Annals of Vascular Surgery Inc.postprin

    Lymphocyte apoptosis, macrophage function and disease activity in systemic lupus erythematosus (SLE)

    Get PDF
    INTRODUCTION: Increased lymphocyte apoptosis and defects in macrophage removal of apoptotic cells have been suggested to contribute to the development of SLE. The aim of this study was to investigate the relationship between peripheral lymphocyte apoptosis, macrophage function as determined by the serum levels of neopterin …published_or_final_versio

    Wavelength-multiplexed duplex transceiver based on III-V/Si hybrid integration for off-chip and on-chip optical interconnects

    Get PDF
    A six-channel wavelength-division-multiplexed optical transceiver with a compact footprint of 1.5 x 0.65 mm(2) for off-chip and on-chip interconnects is demonstrated on a single silicon-on-insulator chip. An arrayed waveguide grating is used as the (de)multiplexer, and III-V electroabsorption sections fabricated by hybrid integration technology are used as both modulators and detectors, which also enable duplex links. The 30-Gb/s capacity for each of the six wavelength channels for the off-chip transceiver is demonstrated. For the on-chip interconnect, an electrical-to-electrical 3-dB bandwidth of 13 GHz and a data rate of 30 Gb/s per wavelength are achieved

    Investigating the genetic and environmental aetiologies of non-suicidal and suicidal self-harm: a twin study

    Get PDF
    BACKGROUND: Self-harm is a major health concern, not only as a signal of distress but also as a strong predictor of later suicide. Self-harm can be further refined into suicidal self-harm (SSH, i.e. suicide attempt) and non-suicidal self-harm (NSSH). Understanding the aetiologies of NSSH and SSH can help inform suicide prevention strategies. Using a twin design, we investigated the phenotypic and aetiological relationships between NSSH and SSH, and their aetiological overlap with mental health problems. METHODS: We analysed data from the Twins Early Development Study using structural equation modelling. At age 21 years, 9063 twins (62.4% female) answered questions related to self-harm. At age 16 years, 19 self- or parent-reported mental health measures were administered, including measures of internalising and externalising problems, psychotic-like experiences and substance abuse. RESULTS: Prevalences for NSSH and SSH were 21.9% and 10.5%, respectively. Additive genetic factors explained half of the variance in NSSH (55%) and SSH (50%), with the rest explained by non-shared environmental factors. Phenotypically, NSSH and SSH were strongly correlated (r = 0.87) with their correlation explained by genetic (57%) and non-shared environmental (43%) factors. We found no evidence that NSSH and SSH differed in their phenotypic and aetiological relationships with mental health measures. CONCLUSION: Our findings suggest no aetiological difference between NSSH and SSH. NSSH and SSH should be regarded as two different ends of a continuum, rather than as two distinct categories

    MEMRI study neonatal hypoxic-ischemic injury in the late stage

    Get PDF
    Session 16: Manganese Enhanced MRI: Methods & Applications - Oral presentationIn this study, in vivo MEMRI was employed to investigate the hypoxic-ischemic injury in the late phase. Mn2+ induced signal changes were examined using SPM coregistration and ROI analysis. T1WIs SI increase was detected in the perilesional region 24 hours after Mn2+ administration and it colocalized with the increase in glial cell density in GFAP staining, demonstrating the existence of reactive gliosis in the late phase after H-I injury.published_or_final_versionThe 17th Scientific Meeting & Exhibition of the International Society of Magnetic Resonance in Medicine (ISMRM), Honolulu, HI., 18-24 April 2009. In Proceedings of ISMRM 17th Scientific Meeting & Exhibition, 2009, p. 15
    • …
    corecore