357 research outputs found

    Coherent electronic transport in a multimode quantum channel with Gaussian-type scatterers

    Full text link
    Coherent electron transport through a quantum channel in the presence of a general extended scattering potential is investigated using a T-matrix Lippmann-Schwinger approach. The formalism is applied to a quantum wire with Gaussian type scattering potentials, which can be used to model a single impurity, a quantum dot or more complicated structures in the wire. The well known dips in the conductance in the presence of attractive impurities is reproduced. A resonant transmission peak in the conductance is seen as the energy of the incident electron coincides with an energy level in the quantum dot. The conductance through a quantum wire in the presence of an asymmetric potential are also shown. In the case of a narrow potential parallel to the wire we find that two dips appear in the same subband which we ascribe to two quasi bound states originating from the next evanescent mode.Comment: RevTeX with 14 postscript figures include

    Coding and regulatory variants are associated with serum protein levels and disease.

    Get PDF
    Circulating proteins can be used to diagnose and predict disease-related outcomes. A deep serum proteome survey recently revealed close associations between serum protein networks and common disease. In the current study, 54,469 low-frequency and common exome-array variants were compared to 4782 protein measurements in the serum of 5343 individuals from the AGES Reykjavik cohort. This analysis identifies a large number of serum proteins with genetic signatures overlapping those of many diseases. More specifically, using a study-wide significance threshold, we find that 2021 independent exome array variants are associated with serum levels of 1942 proteins. These variants reside in genetic loci shared by hundreds of complex disease traits, highlighting serum proteins' emerging role as biomarkers and potential causative agents of a wide range of diseases

    A systematic review on health resilience to economic crises

    Get PDF
    Background The health effects of recent economic crises differ markedly by population group. The objective of this systematic review is to examine evidence from longitudinal studies on factors influencing resilience for any health outcome or health behaviour among the general population living in countries exposed to financial crises. Methods We systematically reviewed studies from six electronic databases (EMBASE, Global Health, MEDLINE, PsycINFO, Scopus, Web of Science) which used quantitative longitudinal study designs and included: (i) exposure to an economic crisis; (ii) changes in health outcomes/behaviours over time; (iii) statistical tests of associations of health risk and/or protective factors with health outcomes/behaviours. The quality of the selected studies was appraised using the Quality Assessment Tool for Quantitative Studies. PRISMA reporting guidelines were followed. Results From 14,584 retrieved records, 22 studies met the eligibility criteria. These studies were conducted across 10 countries in Asia, Europe and North America over the past two decades. Ten socio-demographic factors that increased or protected against health risk were identified: gender, age, education, marital status, household size, employment/occupation, income/ financial constraints, personal beliefs, health status, area of residence, and social relations. These studies addressed physical health, mortality, suicide and suicide attempts, mental health, and health behaviours. Women’s mental health appeared more susceptible to crises than men’s. Lower income levels were associated with greater increases in cardiovascular disease, mortality and worse mental health. Employment status was associated with changes in mental health. Associations with age, marital status, and education were less consistent, although higher education was associated with healthier behaviours. Conclusions Despite widespread rhetoric about the importance of resilience, there was a dearth of studies which operationalised resilience factors. Future conceptual and empirical research is needed to develop the epidemiology of resilience

    Instantaneous wave-free ratio compared with fractional flow reserve in PCI: A cost-minimization analysis.

    Get PDF
    To access publisher's full text version of this article, please click on the hyperlink in Additional Links field or click on the hyperlink at the top of the page marked DownloadBackground: Coronary physiology is a routine diagnostic tool when assessing whether coronary revascularization is indicated. The iFR-SWEDEHEART trial demonstrated similar clinical outcomes when using instantaneous wave-free ratio (iFR) or fractional flow reserve (FFR) to guide revascularization. The objective of this analysis was to assess a cost-minimization analysis of iFR-guided compared with FFR-guided revascularization. Methods: In this cost-minimization analysis we used a decision-tree model from a healthcare perspective with a time-horizon of one year to estimate the cost difference between iFR and FFR in a Nordic setting and a United States (US) setting. Treatment pathways and health care utilizations were constructed from the iFR-SWEDEHEART trial. Unit cost for revascularization and myocardial infarction in the Nordic setting and US setting were derived from the Nordic diagnosis-related group versus Medicare cost data. Unit cost of intravenous adenosine administration and cost per stent placed were based on the average costs from the enrolled centers in the iFR-SWEDEHEART trial. Deterministic and probabilistic sensitivity analyses were carried out to test the robustness of the result. Results: The cost-minimization analysis demonstrated a cost saving per patient of 681(95681 (95% CI: 641 - 723)intheNordicsettingand723) in the Nordic setting and 1024 (95% CI: 934934 - 1114) in the US setting, when using iFR-guided compared with FFR-guided revascularization. The results were not sensitive to changes in uncertain parameters or assumptions. Conclusions: IFR-guided revascularization is associated with significant savings in cost compared with FFR-guided revascularization. Keywords: Cost-minimization analysis; Fractional flow reserve; Instantaneous wave-free ratio.Philips Volcan

    STAT-1 decoy oligodeoxynucleotide inhibition of acute rejection in mouse heart transplants

    Get PDF
    During acute rejection of cardiac transplants endothelial cell–leukocyte interaction fuelled by co-stimulatory molecules like CD40/CD154 may ultimately lead to graft loss. One key player in up-regulating the expression of such pro-inflammatory gene products is the interferon-γ-dependent transcription factor STAT-1. Hence down-regulating interferon-γ-stimulated pro-inflammatory gene expression in the graft endothelial cells by employing a decoy oligodeoxynucleotide (dODN) neutralising STAT-1 may protect the graft. To verify this hypothesis, heterotopic mouse heart transplantation was performed in the allogeneic B10.A(2R) to C57BL/6 and syngeneic C57BL/6 to C57BL/6 strain combination without immunosuppression. Graft vessels were pre-treated with STAT-1 dODN, mutant control ODN (10 μM each) or vehicle (Ringer solution). Cellular rejection (vascular and interstitial component) was graded histologically and CD40, ICAM-1, VCAM-1, MCP-1, E-selectin and RANTES expression in the graft monitored by real time PCR 24 h and 9 days post-transplantation. Nine days after transplantation both rejection scores were significantly diminished by 85 and 70%, respectively, in STAT-1 dODN-treated allografts as compared to mutant control ODN-treated allografts. According to immunohistochemistry analysis, this was accompanied by a reduced infiltration of monocyte/macrophages and T cells into the graft myocardium. In addition, pro-inflammatory gene expression was strongly impaired by more than 80% in STAT-1 dODN-treated allografts 24 h post-transplantation but not in mutant control ODN or vehicle-treated allografts. This inhibitory effect on pro-inflammatory gene expression was no longer detectable 9 days post-transplantation. Single periprocedural treatment with a STAT-1 dODN thus effectively reduces cellular rejection in mouse heart allografts. This effect is associated both with an early decline in pro-inflammatory gene expression and a later drop in mononuclear cell infiltration

    Assessing knowledge of human papillomavirus and collecting data on sexual behavior: computer assisted telephone versus face to face interviews

    Get PDF
    <p>Abstract</p> <p>Background</p> <p>Education campaigns seeking to raise awareness of human papillomavirus (HPV) and promoting HPV vaccination depend on accurate surveys of public awareness and knowledge of HPV and related sexual behavior. However, the most recent population-based studies have relied largely on computer-assisted telephone interviews (CATI) as opposed to face to face interviews (FTFI). It is currently unknown how these survey modes differ, and in particular whether they attract similar demographics and therefore lead to similar overall findings.</p> <p>Methods</p> <p>A comprehensive survey of HPV awareness and knowledge, including sexual behavior, was conducted among 3,045 Singaporean men and women, half of whom participated via CATI, the other half via FTFI.</p> <p>Results</p> <p>Overall levels of awareness and knowledge of HPV differed between CATI and FTFI, attributable in part to demographic variations between these survey modes. Although disclosure of sexual behavior was greater when using CATI, few differences between survey modes were found in the actual information disclosed.</p> <p>Conclusion</p> <p>Although CATI is a cheaper, faster alternative to FTFI and people appear more willing to provide information about sexual behavior when surveyed using CATI, thorough assessments of HPV awareness and knowledge depend on multiple survey modes.</p

    Technology-Supported Storytelling (TSST) Strategy in Virtual World for Multicultural Education

    Get PDF
    Learning culture through stories is an effective way for multicultural education, since stories are one of the most powerful and personal ways that we learn about the world. Storytelling, the process of telling stories, is a form of communication and a universal expression of culture. With the development of technology, storytelling emerges out of diverse ways. This study explores the storytelling in virtual worlds for multicultural education, and devises a Technology-Supported storytelling (TSST) strategy by examining and considering the characteristics of virtual worlds which could be incorporated into the storytelling, and then uses this strategy to teach Korean culture to students with different culture background. With this innovative TSST strategy in virtual world, this study expects to provide a guide to practice for teaching multicultural in digital era

    A Novel Adaptive Method for the Analysis of Next-Generation Sequencing Data to Detect Complex Trait Associations with Rare Variants Due to Gene Main Effects and Interactions

    Get PDF
    There is solid evidence that rare variants contribute to complex disease etiology. Next-generation sequencing technologies make it possible to uncover rare variants within candidate genes, exomes, and genomes. Working in a novel framework, the kernel-based adaptive cluster (KBAC) was developed to perform powerful gene/locus based rare variant association testing. The KBAC combines variant classification and association testing in a coherent framework. Covariates can also be incorporated in the analysis to control for potential confounders including age, sex, and population substructure. To evaluate the power of KBAC: 1) variant data was simulated using rigorous population genetic models for both Europeans and Africans, with parameters estimated from sequence data, and 2) phenotypes were generated using models motivated by complex diseases including breast cancer and Hirschsprung's disease. It is demonstrated that the KBAC has superior power compared to other rare variant analysis methods, such as the combined multivariate and collapsing and weight sum statistic. In the presence of variant misclassification and gene interaction, association testing using KBAC is particularly advantageous. The KBAC method was also applied to test for associations, using sequence data from the Dallas Heart Study, between energy metabolism traits and rare variants in ANGPTL 3,4,5 and 6 genes. A number of novel associations were identified, including the associations of high density lipoprotein and very low density lipoprotein with ANGPTL4. The KBAC method is implemented in a user-friendly R package
    corecore