200 research outputs found
Entomologic and Serologic Evidence of Zoonotic Transmission of Babesia microti, Eastern Switzerland
We evaluated human risk for infection with Babesia microti at a site in eastern Switzerland where several B. microti–infected nymphal Ixodes ricinus ticks had been found. DNA from pooled nymphal ticks amplified by polymerase chain reaction was highly homologous to published B. microti sequences. More ticks carried babesial infection in the lower portion of the rectangular 0.7-ha grid than in the upper (11% vs. 0.8%). In addition, we measured seroprevalence of immunoglobulin (Ig) G antibodies against B. microti antigen in nearby residents. Serum from 1.5% of the 396 human residents of the region reacted to B. microti antigen (>1:64), as determined by indirect immunofluorescence assay (IgG). These observations constitute the first report demonstrating B. microti in a human-biting vector, associated with evidence of human exposure to this agent in a European site
The role of hole transport between dyes in solid-state dye-sensitized solar cells
In dye-sensitized solar cells (DSSCs)
photogenerated positive charges
are normally considered to be carried away from the dyes by a separate
phase of hole-transporting material (HTM). We show that there can
also be significant transport within the dye monolayer itself before
the hole reaches the HTM. We quantify the fraction of dye regeneration
in solid-state DSSCs that can be attributed to this process. By using
cyclic voltammetry and transient anisotropy spectroscopy, we demonstrate
that the rate of interdye hole transport is prevented both on micrometer
and nanometer length scales by reducing the dye loading on the TiO<sub>2</sub> surface. The dye regeneration yield is quantified for films
with high and low dye loadings (with and without hole percolation
in the dye monolayer) infiltrated with varying levels of HTM. Interdye
hole transport can account for >50% of the overall dye regeneration
with low HTM pore filling. This is reduced to about 5% when the infiltration
of the HTM in the pores is optimized in 2 ÎĽm thick films. Finally,
we use hole transport in the dye monolayer to characterize the spatial
distribution of the HTM phase in the pores of the dyed mesoporous
TiO<sub>2</sub>
Hepatitis A Virus Cellular Receptor 1 (HAVcr-1) Initiates Prostate Cancer Progression in Human Cells via Hepatocyte Growth Factor (HGF)-Induced Changes in Junctional Integrity
Background: HAVcR-1 has been linked to cancer aetiology and may regulate junctional complexes, with its role in prostate cancer still unexplored. This study aims to investigate the expression of HAVcR-1 in prostate cancer samples and the exploration of the cellular/molecular impact of HAVcR-1.
Methods: Levels of HAVcR-1 ectodomain in the serum of prostate cancer patients were compared to healthy controls, and assessed as the total protein and gene expression of HAVcR-1 and tissues sections. The manipulation of HAVcR-1 levels within prostate cancer cell lines determined changes in cell behaviour using in vitro cell models and barrier function assays. Protein/phosphoprotein levels were assessed using Western blotting.
Results: Levels of HAVcR-1 ectodomain from serum were decreased in patients with prostate cancer. Ectodomain levels correlated with the Gleason score. Histologically, the total protein/gene expression of HAVcR-1 was overexpressed in prostate cancer. The overexpression of HAVcR-1 in prostate cancer cell lines resulted in key changes in cell behaviour and the phosphorylation of β-catenin with a concurrent decrease in membranous E-cadherin, increased nuclear β-catenin and increased cyclin D1 protein expression, which were associated with HGF-promoted changes in the barrier function.
Conclusions: HAVcR-1 expression and ectodomain release coincides with the presence of prostate cancer; thus, indicating HAVcR-1 as a potential biomarker to aid in diagnostics, and implicating HAVcR-1 in the dysregulation of junctional complexes
Identifying Dominant Recombination Mechanisms in Perovskite Solar Cells by Measuring the Transient Ideality Factor
The light ideality factor determined by measuring the open-circuit voltage (V) as a function of light intensity is often used to identify the dominant recombination mechanism in solar cells. Applying this “Suns-V” technique to perovskite cells is problematic since the V evolves with time in a way that depends on the previously applied bias (V), bias light intensity, device architecture and processing route. Here, we show that the dominant recombination mechanism in two structurally similar CH3NH3PbI3 devices containing either mesoporous Al2O3 or TiO2 layers can be identified from the signature of the transient ideality factor following application of a forward bias, V, to the device in the dark. The transient ideality factor is measured by monitoring the evolution of V as a function of time at different light intensities. The initial values of ideality found using this technique are consistent with estimates of the ideality factor obtained from measurements of photoluminescence vs light intensity and electroluminescence vs current density. Time-dependent simulations of the measurement on modeled devices, which include the effects of mobile ionic charge, reveal that this initial value can be correlated to an existing zero-dimensional model while steady-state values must be analyzed taking into account the homogeneity of carrier populations throughout the absorber layer. The analysis shows that Shockley-Read-Hall (SRH) recombination through deep traps at the charge-collection interfaces is dominant in both architectures of measured device. Using transient photovoltage measurements directly following illumination on bifacial devices, we further show that the perovskite–electron-transport-layer interface extends throughout the mesoporous TiO2 layer, consistent with a transient ideality signature corresponding to SRH recombination in the bulk of the film. This method will be useful for identifying performance bottlenecks in alternative variants of perovskite and other mixed ionic-electronic conducting absorber-based solar cells
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Open Science principles for accelerating trait-based science across the Tree of Life.
Synthesizing trait observations and knowledge across the Tree of Life remains a grand challenge for biodiversity science. Species traits are widely used in ecological and evolutionary science, and new data and methods have proliferated rapidly. Yet accessing and integrating disparate data sources remains a considerable challenge, slowing progress toward a global synthesis to integrate trait data across organisms. Trait science needs a vision for achieving global integration across all organisms. Here, we outline how the adoption of key Open Science principles-open data, open source and open methods-is transforming trait science, increasing transparency, democratizing access and accelerating global synthesis. To enhance widespread adoption of these principles, we introduce the Open Traits Network (OTN), a global, decentralized community welcoming all researchers and institutions pursuing the collaborative goal of standardizing and integrating trait data across organisms. We demonstrate how adherence to Open Science principles is key to the OTN community and outline five activities that can accelerate the synthesis of trait data across the Tree of Life, thereby facilitating rapid advances to address scientific inquiries and environmental issues. Lessons learned along the path to a global synthesis of trait data will provide a framework for addressing similarly complex data science and informatics challenges
A global perspective on marine photosynthetic picoeukaryote community structure
A central goal in ecology is to understand the factors affecting the temporal dynamics and spatial distribution of microorganisms and the underlying processes causing differences in community structure and composition. However, little is known in this respect for photosynthetic picoeukaryotes (PPEs), algae that are now recognised as major players in marine CO2 fixation. Here, we analysed dot blot hybridisation and cloning–sequencing data, using the plastid-encoded 16S rRNA gene, from seven research cruises that encompassed all four ocean biomes. We provide insights into global abundance, α- and β-diversity distribution and the environmental factors shaping PPE community structure and composition. At the class level, the most commonly encountered PPEs were Prymnesiophyceae and Chrysophyceae. These taxa displayed complementary distribution patterns, with peak abundances of Prymnesiophyceae and Chrysophyceae in waters of high (25:1) or low (12:1) nitrogen:phosphorus (N:P) ratio, respectively. Significant differences in phylogenetic composition of PPEs were demonstrated for higher taxonomic levels between ocean basins, using Unifrac analyses of clone library sequence data. Differences in composition were generally greater between basins (interbasins) than within a basin (intrabasin). These differences were primarily linked to taxonomic variation in the composition of Prymnesiophyceae and Prasinophyceae whereas Chrysophyceae were phylogenetically similar in all libraries. These data provide better knowledge of PPE community structure across the world ocean and are crucial in assessing their evolution and contribution to CO2 fixation, especially in the context of global climate change
Children’s sedentary behaviour: descriptive epidemiology and associations with objectively-measured sedentary time
Background: Little is known regarding the patterning and socio-demographic distribution of multiple sedentary behaviours in children. The aims of this study were to: 1) describe the leisure-time sedentary behaviour of 9-10 year old British children, and 2) establish associations with objectively-measured sedentary time. Methods: Cross-sectional analysis in the SPEEDY study (Sport, Physical activity and Eating behaviour: Environmental Determinants in Young people) (N=1513, 44.3% boys). Twelve leisure-time sedentary behaviours were assessed by questionnaire. Objectively-measured leisure-time sedentary time (Actigraph GT1M, <100 counts/minute) was assessed over 7 days. Differences by sex and socioeconomic status (SES) in self-reported sedentary behaviours were tested using Kruskal-Wallis tests. The association between objectively-measured sedentary time and the separate sedentary behaviours (continuous (minutes) and categorised into 'none' 'low' or 'high' participation) was assessed using multi-level linear regression. Results: Sex differences were observed for time spent in most sedentary behaviours (all p ≤ 0.02), except computer use. Girls spent more time in combined non-screen sedentary behaviour (median, interquartile range: girls: 770.0 minutes, 390.0-1230.0; boys: 725.0, 365.0 - 1182.5; p = 0.003), whereas boys spent more time in screen-based behaviours (girls: 540.0, 273.0 - 1050.0; boys: 885.0, 502.5 - 1665.0; p < 0.001). Time spent in five non-screen behaviours differed by SES, with higher values in those of higher SES (all p ≤ 0.001). Regression analyses with continuous exposures indicated that reading (β = 0.1, p < 0.001) and watching television (β = 0.04, p < 0.01) were positively associated with objectively-measured sedentary time, whilst playing board games (β = -0.12, p < 0.05) was negatively associated. Analysed in categorical form, sitting and talking (vs. none: 'low' β = 26.1,ns; 'high' 30.9, p < 0.05), playing video games (vs. none: 'low' β = 49.1, p < 0.01; 'high' 60.2, p < 0.01) and watching television (vs. lowest tertile: middle β = 22.2,ns; highest β = 31.9, p < 0.05) were positively associated with objectively-measured sedentary time whereas talking on the phone (vs. none: 'low' β = -38.5, p < 0.01; 'high' -60.2, p < 0.01) and using a computer/internet (vs. none: 'low' β = -30.7, p < 0.05; 'high' -4.2,ns) were negatively associated. Conclusions: Boys and girls and children of different socioeconomic backgrounds engage in different leisure-time sedentary behaviours. Whilst a number of behaviours may be predictive of total sedentary time, collectively they explain little overall variance. Future studies should consider a wide range of sedentary behaviours and incorporate objective measures to quantify sedentary time where possible
The Astropy Problem
The Astropy Project (http://astropy.org) is, in its own words, "a community
effort to develop a single core package for Astronomy in Python and foster
interoperability between Python astronomy packages." For five years this
project has been managed, written, and operated as a grassroots,
self-organized, almost entirely volunteer effort while the software is used by
the majority of the astronomical community. Despite this, the project has
always been and remains to this day effectively unfunded. Further, contributors
receive little or no formal recognition for creating and supporting what is now
critical software. This paper explores the problem in detail, outlines possible
solutions to correct this, and presents a few suggestions on how to address the
sustainability of general purpose astronomical software
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