7,081 research outputs found
The relationship between built-up areas and the spatial development of the mean maximum urban heat island in Debrecen, Hungary
The climate of built-up regions differs significantly from rural regions and the most important modifying effect of urbanization on local climate is the urban temperature excess, otherwise called the urban heat island (UHI). This study examines the influence of built-up areas on the near-surface air temperature field in the case of the medium-sized city of Debrecen, Hungary. Mobile measurements were used under different weather conditions between March 2002 and March 2003. Efforts concentrated on the determination of the spatial distribution of mean maximum UHI intensity with special regard to land-use features such as built-up ratio and its areal extensions. In both (heating and non-heating) seasons the spatial distribution of the UHI intensity field showed a basically concentric shape with local anomalies. The mean maximum UHI intensity reaches more than 2.0 degrees C (heating season) and 2.5 degrees C (non-heating season) in the centre of the city. We established the relationship between the above-mentioned land-use parameters and mean maximum UHI intensity by means of multiple linear regression analysis. As the measured and predicted mean maximum UHI intensity patterns show, there is an obvious connection between the spatial distribution of urban thermal excess and the land-use parameters examined, so these parameters play a significant role in the development of the strong, UHI intensity field over the city. Copyright (c) 2005 Royal Meteorological Society
Probing Spin-Charge Relation by Magnetoconductance in One-Dimensional Polymer Nanofibers
Polymer nanofibers are one-dimensional organic hydrocarbon systems containing
conducting polymers where the non-linear local excitations such as solitons,
polarons and bipolarons formed by the electron-phonon interaction were
predicted. Magnetoconductance (MC) can simultaneously probe both the spin and
charge of these mobile species and identify the effects of electron-electron
interactions on these nonlinear excitations. Here we report our observations of
a qualitatively different MC in polyacetylene (PA) and in polyaniline (PANI)
and polythiophene (PT) nanofibers. In PA the MC is essentially zero, but it is
present in PANI and PT. The universal scaling behavior and the zero (finite) MC
in PA (PANI and PT) nanofibers provide evidence of Coulomb interactions between
spinless charged solitons (interacting polarons which carry both spin and
charge)
Metallic 1T Phase, 3d1 Electronic Configuration and Charge Density Wave Order in Molecular Beam Epitaxy Grown Monolayer Vanadium Ditelluride.
We present a combined experimental and theoretical study of monolayer vanadium ditelluride, VTe2, grown on highly oriented pyrolytic graphite by molecular-beam epitaxy. Using various in situ microscopic and spectroscopic techniques, including scanning tunneling microscopy/spectroscopy, synchrotron X-ray and angle-resolved photoemission, and X-ray absorption, together with theoretical analysis by density functional theory calculations, we demonstrate direct evidence of the metallic 1T phase and 3d1 electronic configuration in monolayer VTe2 that also features a (4 × 4) charge density wave order at low temperatures. In contrast to previous theoretical predictions, our element-specific characterization by X-ray magnetic circular dichroism rules out a ferromagnetic order intrinsic to the monolayer. Our findings provide essential knowledge necessary for understanding this interesting yet less explored metallic monolayer in the emerging family of van der Waals magnets
130 - Interventions for treating obstetric fistula: Results of an evidence gap map
HYPOTHESIS / AIMS OF STUDY: Obstetric fistula is a debilitating condition prevalent in low- and middle-income countries; it is estimated that there are between 50,000 to 100,000 new cases each year. The World Health Organization (WHO) aims to eradicate obstetric fistula by 2030. However, there is no overview of the breadth and quality of evidence surrounding interventions for obstetric fistula to inform current practice. Evidence gap maps (EGMs) are a type of evidence synthesis used to visualise the breadth of research on a specific topic area. This EGM aimed to collate and visualise the evidence available on obstetric fistula interventions and to identify potential research gaps. STUDY DESIGN, MATERIALS AND METHODS: A survey was conducted so key stakeholders (e.g. clinicians, patients, the public or researchers) could rank the most important intervention categories and outcome measures for research into obstetric fistula to assist in designing the framework for the EGM. The survey was developed using Qualtrics, a secure web-based platform and was distributed on 16 February 2022 to professional and charitable organisations with an interest in obstetric fistula as well as clinical contacts. The survey invite was allowed to snowball from initial distribution contacts and remained open until 14 March 2022. Results of the survey were tabulated and analysed in Microsoft Excel by a single reviewer and used to inform the EGM framework. Search strategies for the EGM were peer-reviewed by an experienced Information Specialist before being undertaken on MEDLINE, Embase, CENTRAL, Global Index Medicus and ScanMedicine on 16 February 2022 to identify potentially eligible systematic reviews, randomised controlled trials (RCTs), cohort studies and case-control studies. All studies were screened at title and abstract and full-text stages by a single reviewer according to a pre-defined Population, Intervention, Comparison and Outcome (PICO) criteria. A second reviewer screened 10% of records at both stages to check accuracy of decision-making. To ensure directness of the evidence in the EGM to the population of interest, only studies with at least 80% of women having fistula of obstetric aetiology were included. Where fistula aetiology was not explicitly described in demographic information but alluded to in titles, these were included in the EGM but subjected to sensitivity analysis. Forward and backward citation chaining was performed on all included systematic reviews and primary studies to identify any potentially eligible studies the searches may have missed .Included systematic reviews and primary studies were coded by a single reviewer within EPPI-Reviewer using a a pre-piloted coding tool informed by the stakeholder survey. Another reviewer coded a proportion of these records to check accuracy. Risk of bias assessments for all included reports were conducted by a single reviewer using either: AMSTAR-2 for systematic reviews; Cochrane’s ‘Risk of bias’ tool for RCTs; or the Joanna Briggs Institute (JBI) checklists for cohort and case-control studies. A second reviewer checked 20% of these assessments for accuracy. Following coding, the EGM was generated using the EPPI-Mapper wizard and results were compared with survey findings to identify research gaps correlating with unmet needs. A single sensitivity analysis was undertaken using specific filters within the EGM to determine the amount of research where at least 80% of the included population explicitly had fistula of obstetric origin and that reported on the effects of different interventions separately. RESULTS:: In total, 39 people responded to the stakeholder survey, 59% of whom were clinicians. The respondents identified surgery for obstetric fistula as the most important intervention category for underpinning research. According to the survey, the most important outcome measures for research were: quality of life; cure and improvement of obstetric fistula; urinary incontinence; faecal incontinence; mental health; and sexual function. Of the 9796 records originally identified by database searches, only 37 reports of 28 studies were considered eligible for the EGM (Fig. 1). In total, the EGM included: seven RCTs; six prospective cohort studies; 12 retrospective cohort studies; one historical cohort study; one case-control study; and one systematic review. Most studies (n = 17) exclusively examined women with vesicovaginal fistula. Most included studies (71%) assessed the effects of surgery on treating obstetric fistula, while one focused on psychological interventions, four on catheter insertion and one on physical therapies. No included studies assessed the effects of lifestyle interventions. Regarding outcome measures, 24 studies reported on cure or improvement of obstetric fistula, while 20 reported on urinary incontinence. Reporting of other key outcome measures identified by the stakeholder survey was limited; only two studies reported on quality of life, while two studies reported on faecal incontinence, one on mental health and one on sexual function. Furthermore, the results of the sensitivity analysis removed all studies assessing psychological or physical therapy, while no RCTs assessing surgery remained in the EGM. INTERPRETATION OF RESULTS: The overall lack of evidence identified for the EGM, particularly for outcome measures identified as important to key stakeholders, suggests there is currently little evidence to guide practice and policy. The results of the sensitivity analysis demonstrates that the overall applicability of the current evidence specifically to women with obstetric fistula is limited and that subsequent systematic reviews may currently not be feasible. Many of the included studies were at some risk of bias. Cohort and case-control studies were at particular risk of bias, mainly due to a lack of controlling for potential confounders. CONCLUDING MESSAGE: Currently, there is little robust evidence to guide women and practitioners on treatment options for obstetric fistula. Further research is required to address the research gaps identified by this EGM. FIGURE 1: Funding This work was supported by Newcastle University as part of Training Fellowships awarded to EEJ and NO’C, Newcastle University as part of a tenured post awarded to LV, and various National Institute for Health Research (NIHR) funding, including the NIHR Innovation Observatory, for FP. Neither Newcastle University nor the NIHR had any role in study design, data collection and analysis, decision to submit for presentation and publication. PH and JG did not receive funding for this work. Clinical Trial No Subjects Non
The S-layer Associated Serine Protease Homolog PrtX Impacts Cell Surface-Mediated Microbe-Host Interactions of Lactobacillus acidophilus NCFM
Health-promoting aspects attributed to probiotic microorganisms, including adhesion to intestinal epithelia and modulation of the host mucosal immune system, are mediated by proteins found on the bacterial cell surface. Notably, certain probiotic and commensal bacteria contain a surface (S-) layer as the outermost stratum of the cell wall. S-layers are non-covalently bound semi-porous, crystalline arrays of self-assembling, proteinaceous subunits called S-layer proteins (SLPs). Recent evidence has shown that multiple proteins are non-covalently co-localized within the S-layer, designated S-layer associated proteins (SLAPs). In Lactobacillus acidophilus NCFM, SLP and SLAPs have been implicated in both mucosal immunomodulation and adhesion to the host intestinal epithelium. In this study, a S-layer associated serine protease homolog, PrtX (prtX, lba1578), was deleted from the chromosome of L. acidophilus NCFM. Compared to the parent strain, the PrtX-deficient strain (ΔprtX) demonstrated increased autoaggregation, an altered cellular morphology, and pleiotropic increases in adhesion to mucin and fibronectin, in vitro. Furthermore, ΔprtX demonstrated increased in vitro immune stimulation of IL-6, IL-12, and IL-10 compared to wild-type, when exposed to mouse dendritic cells. Finally, in vivo colonization of germ-free mice with ΔprtX led to an increase in epithelial barrier integrity. The absence of PrtX within the exoproteome of a ΔprtX strain caused morphological changes, resulting in a pleiotropic increase of the organisms’ immunomodulatory properties and interactions with some intestinal epithelial cell components
Correction to Metallic 1T Phase, 3d1 Electronic Configuration and Charge Density Wave Order in Molecular-Beam Epitaxy Grown Monolayer Vanadium Ditelluride.
It has been brought to our attention that a mistake exists in the author list. The author “Johnson Goh” in the original article should be “Kuan Eng Johnson Goh”. His primary corresponding email is [email protected]
Defects in WS2 monolayer calculated with a nonlocal functional: any difference from GGA?
Density Functional Theory (DFT) with Generalized Gradient Approximation (GGA) functionals is commonly used to predict defect properties in 2D transition metal dichalcogenides (TMDs). Since GGA functionals often underestimate bandgaps of semiconductors and incorrectly describe the character of electron localization in defects and their level positions within the band-gap, it is important to assess the accuracy of these predictions. To this end, we used the non-local density functional PBE0-TC-LRC to calculate the properties of a wide range of intrinsic defects in monolayer WS2. The properties, such as geometry, in-gap states, charge transition levels, electronic structure and the electron/hole localization of the lowest formation energy defects are discussed in detail. They are broadly similar to those predicted by the GGA PBE functional but exhibit numerous quantitative differences caused by the degree of electron and hole localization in charged states. For some anti-site defects, more significant differences are seen, with both changes in defect geometries (differences of up to 0.5 Å) as well as defect level positions within the band gap of WS2. This work provides an insight into the performance of functionals chosen for future DFT calculations of transition metal dichalcogenides with respect to the desired defect properties
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