385 research outputs found

    A Novel Approach to Standard Techniques in the Assessment and Quantification of the Interventricular Systolic Relationship

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    <p>Abstract</p> <p>Background</p> <p>Blood flow between the right and left ventricles is subject to the continuity equation and systolic ventricular interdependence. Quantification of this relationship might aid in understanding inter-ventricular function. The purpose of this study was to evaluate and quantify ventricular interdependence by directly comparing right and left ventricular systolic function though echocardiographic surrogates of right and left ventricular systolic function such as MAPSE, TAPSE, RV TVI and LV TVI.</p> <p>Methods</p> <p>This study prospectively evaluated 51 healthy participants (mean age, 41 ± 17 years) by resting echocardiography. In addition to standard measurements, tricuspid annular plane of systolic excursion, (TAPSE), mitral annular plane of systolic excursion (MAPSE), and the peak annulus systolic velocity of the right ventricular (RVs) and left ventricular (LVs) free walls were measured by M-mode and pulsed wave Doppler tissue echocardiography and further evaluated for variance across age, gender, and body surface area.</p> <p>Results</p> <p>TAPSE (22.1 ± 2.9 mm) was over 54.5% greater than MAPSE (14.3 ± 2.6 mm) and RVs was 64.4% greater than LVs. The LV to RV systolic relationship measured by MAPSE/TAPSE and LVs/RVs ratios were 0.66 ± 0.14 and 0.76 ± 0.21 respectively. These values were not significantly affected by age, gender or body surface area (BSA).</p> <p>Conclusion</p> <p>MAPSE/TAPSE and LVs/RVs ratios appear stable across age, gender, and BSA potentially making them good surrogates of systolic ventricular relationship and interdependence.</p

    Galaxy Zoo: Dust in Spirals

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    We investigate the effect of dust on spiral galaxies by measuring the inclination-dependence of optical colours for 24,276 well-resolved SDSS galaxies visually classified in Galaxy Zoo. We find clear trends of reddening with inclination which imply a total extinction from face-on to edge-on of 0.7, 0.6, 0.5 and 0.4 magnitudes for the ugri passbands. We split the sample into "bulgy" (early-type) and "disky" (late-type) spirals using the SDSS fracdeV (or f_DeV) parameter and show that the average face-on colour of "bulgy" spirals is redder than the average edge-on colour of "disky" spirals. This shows that the observed optical colour of a spiral galaxy is determined almost equally by the spiral type (via the bulge-disk ratio and stellar populations), and reddening due to dust. We find that both luminosity and spiral type affect the total amount of extinction, with "disky" spirals at M_r ~ -21.5 mags having the most reddening. This decrease of reddening for the most luminous spirals has not been observed before and may be related to their lower levels of recent star formation. We compare our results with the latest dust attenuation models of Tuffs et al. We find that the model reproduces the observed trends reasonably well but overpredicts the amount of u-band attenuation in edge-on galaxies. We end by discussing the effects of dust on large galaxy surveys and emphasize that these effects will become important as we push to higher precision measurements of galaxy properties and their clustering.Comment: MNRAS in press. 25 pages, 22 figures (including an abstract comparing GZ classifications with common automated methods for selecting disk/early type galaxies in SDSS data). v2 corrects typos found in proof

    Systematic review of communication technologies to promote access and engagement of young people with diabetes into healthcare

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    Background: Research has investigated whether communication technologies (e.g. mobile telephony, forums, email) can be used to transfer digital information between healthcare professionals and young people who live with diabetes. The systematic review evaluates the effectiveness and impact of these technologies on communication. Methods: Nine electronic databases were searched. Technologies were described and a narrative synthesis of all studies was undertaken. Results: Of 20,925 publications identified, 19 met the inclusion criteria, with 18 technologies assessed. Five categories of communication technologies were identified: video-and tele-conferencing (n = 2); mobile telephony (n = 3); telephone support (n = 3); novel electronic communication devices for transferring clinical information (n = 10); and web-based discussion boards (n = 1). Ten studies showed a positive improvement in HbA1c following the intervention with four studies reporting detrimental increases in HbA1c levels. In fifteen studies communication technologies increased the frequency of contact between patient and healthcare professional. Findings were inconsistent of an association between improvements in HbA1c and increased contact. Limited evidence was available concerning behavioural and care coordination outcomes, although improvement in quality of life, patientcaregiver interaction, self-care and metabolic transmission were reported for some communication technologies. Conclusions: The breadth of study design and types of technologies reported make the magnitude of benefit and their effects on health difficult to determine. While communication technologies may increase the frequency of contact between patient and health care professional, it remains unclear whether this results in improved outcomes and is often the basis of the intervention itself. Further research is needed to explore the effectiveness and cost effectiveness of increasing the use of communication technologies between young people and healthcare professionals

    Fifteen new risk loci for coronary artery disease highlight arterial-wall-specific mechanisms

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    Coronary artery disease (CAD) is a leading cause of morbidity and mortality worldwide. Although 58 genomic regions have been associated with CAD thus far, most of the heritability is unexplained, indicating that additional susceptibility loci await identification. An efficient discovery strategy may be larger-scale evaluation of promising associations suggested by genome-wide association studies (GWAS). Hence, we genotyped 56,309 participants using a targeted gene array derived from earlier GWAS results and performed meta-analysis of results with 194,427 participants previously genotyped, totaling 88,192 CAD cases and 162,544 controls. We identified 25 new SNP-CAD associations (P &lt; 5 × 10(-8), in fixed-effects meta-analysis) from 15 genomic regions, including SNPs in or near genes involved in cellular adhesion, leukocyte migration and atherosclerosis (PECAM1, rs1867624), coagulation and inflammation (PROCR, rs867186 (p.Ser219Gly)) and vascular smooth muscle cell differentiation (LMOD1, rs2820315). Correlation of these regions with cell-type-specific gene expression and plasma protein levels sheds light on potential disease mechanisms

    Plasmodium falciparum sulfadoxine resistance is geographically and genetically clustered within the DR Congo

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    Understanding the spatial clustering of Plasmodium falciparum populations can assist efforts to contain drug-resistant parasites and maintain the efficacy of future drugs. We sequenced single nucleotide polymorphisms (SNPs) in the dihydropteroate synthase gene (dhps) associated with sulfadoxine resistance and 5 microsatellite loci flanking dhps in order to investigate the genetic backgrounds, genetic relatedness, and geographic clustering of falciparum parasites in the Democratic Republic of the Congo (DRC). Resistant haplotypes were clustered into subpopulations: one in the northeast DRC, and the other in the balance of the DRC. Network and clonal lineage analyses of the flanking microsatellites indicate that geographically-distinct mutant dhps haplotypes derive from separate lineages. The DRC is therefore a watershed for haplotypes associated with sulfadoxine resistance. Given the importance of central Africa as a corridor for the spread of antimalarial resistance, the identification of the mechanisms of this transit can inform future policies to contain drug-resistant parasite strains

    Anti-phospholipid human monoclonal antibodies inhibit CCR5-tropic HIV-1 and induce β-chemokines

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    Traditional antibody-mediated neutralization of HIV-1 infection is thought to result from the binding of antibodies to virions, thus preventing virus entry. However, antibodies that broadly neutralize HIV-1 are rare and are not induced by current vaccines. We report that four human anti-phospholipid monoclonal antibodies (mAbs) (PGN632, P1, IS4, and CL1) inhibit HIV-1 CCR5-tropic (R5) primary isolate infection of peripheral blood mononuclear cells (PBMCs) with 80% inhibitory concentrations of <0.02 to ∼10 µg/ml. Anti-phospholipid mAbs inhibited PBMC HIV-1 infection in vitro by mechanisms involving binding to monocytes and triggering the release of MIP-1α and MIP-1β. The release of these β-chemokines explains both the specificity for R5 HIV-1 and the activity of these mAbs in PBMC cultures containing both primary lymphocytes and monocytes

    Using a population-based approach to prevent hepatocellular cancer in New South Wales, Australia: effects on health services utilisation

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    <p>Abstract</p> <p>Background</p> <p>Australians born in countries where hepatitis B infection is endemic are 6-12 times more likely to develop hepatocellular cancer (HCC) than Australian-born individuals. However, a program of screening, surveillance and treatment of chronic hepatitis B (CHB) in high risk populations could significantly reduce disease progression and death related to end-stage liver disease and HCC. Consequently we are implementing the <it>B Positive </it>pilot project, aiming to optimise the management of CHB in at-risk populations in south-west Sydney. Program participants receive routine care, enhanced disease surveillance or specialist referral, according to their stage of CHB infection, level of viral load and extent of liver injury. In this paper we examine the program's potential impact on health services utilisation in the study area.</p> <p>Methods</p> <p>Estimated numbers of CHB infections were derived from Australian Bureau of Statistics data and applying estimates of HBV prevalence rates from migrants' countries of birth. These figures were entered into a Markov model of disease progression, constructing a hypothetical cohort of Asian-born adults with CHB infection. We calculated the number of participants in different CHB disease states and estimated the numbers of GP and specialist consultations and liver ultrasound examinations the cohort would require annually over the life of the program.</p> <p>Results</p> <p>Assuming a 25% participation rate among the 5,800 local residents estimated to have chronic hepatitis B infection, approximately 750 people would require routine follow up, 260 enhanced disease surveillance and 210 specialist care during the first year after recruitment is completed. This translates into 5 additional appointments per year for each local GP, 25 for each specialist and 420 additional liver ultrasound examinations.</p> <p>Conclusions</p> <p>While the program will not greatly affect the volume of local GP consultations, it will lead to a significant increase in demand for specialist services. New models of CHB care may be required to aid program implementation and up scaling the program will need to factor in additional demands on health care utilisation in areas of high hepatitis B sero-prevalence.</p

    A flexible mathematical model platform for studying branching networks : experimentally validated using the model actinomycete, Streptomyces coelicolor

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    Branching networks are ubiquitous in nature and their growth often responds to environmental cues dynamically. Using the antibiotic-producing soil bacterium Streptomyces as a model we have developed a flexible mathematical model platform for the study of branched biological networks. Streptomyces form large aggregates in liquid culture that can impair industrial antibiotic fermentations. Understanding the features of these could aid improvement of such processes. The model requires relatively few experimental values for parameterisation, yet delivers realistic simulations of Streptomyces pellet and is able to predict features, such as the density of hyphae, the number of growing tips and the location of antibiotic production within a pellet in response to pellet size and external nutrient supply. The model is scalable and will find utility in a range of branched biological networks such as angiogenesis, plant root growth and fungal hyphal networks

    Potential for comparative public opinion research in public administration

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    The public administration and public services have always taken a marginal place in the political scientists’ behavioural research. Public administration students on the other hand tend to focus on political and administrative elites and institutions, and largely ignored citizens in comparative research. In this article we make a plea for international comparative research on citizens’ attitudes towards the public administration from an interdisciplinary perspective. Available international survey material is discussed, and main trends in empirical practice and theoretical approaches are outlined, especially those with a potential impact on public sector reform

    ASPCAP: THE APOGEE STELLAR PARAMETER AND CHEMICAL ABUNDANCES PIPELINE

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    The Apache Point Observatory Galactic Evolution Experiment (APOGEE) has built the largest moderately high-resolution (R ≈ 22,500) spectroscopic map of the stars across the Milky Way, and including dust-obscured areas. The APOGEE Stellar Parameter and Chemical Abundances Pipeline (ASPCAP) is the software developed for the automated analysis of these spectra. ASPCAP determines atmospheric parameters and chemical abundances from observed spectra by comparing observed spectra to libraries of theoretical spectra, using χ2 minimization in a multidimensional parameter space. The package consists of a fortran90 code that does the actual minimization and a wrapper IDL code for book-keeping and data handling. This paper explains in detail the ASPCAP components and functionality, and presents results from a number of tests designed to check its performance. ASPCAP provides stellar effective temperatures, surface gravities, and metallicities precise to 2%, 0.1 dex, and 0.05 dex, respectively, for most APOGEE stars, which are predominantly giants. It also provides abundances for up to 15 chemical elements with various levels of precision, typically under 0.1 dex. The final data release (DR12) of the Sloan Digital Sky Survey III contains an APOGEE database of more than 150,000 stars. ASPCAP development continues in the SDSS-IV APOGEE-2 survey
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