2,972 research outputs found

    Triplet Irradiance Measurements

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    Cloud speed and direction govern the dynamic nature of irradiance, and hence the electrical output of PV panels and arrays. For example, ramp rates are directly proportional to the cloud speed and related to the coincidence of cloud direction and array orientation. In this work, we demonstrate that cloud dynamics can be determined using a triplet of silicon irradiance sensors logged at high frequency. Using cross-correlation, cloud speed and direction are calculated from the time shifts of cloud edges detected from sensor pairs. Data was initially recorded for 5 months from March 2016, near Leeds, UK. Further data will be recorded in 2018, near Kampala, Uganda. From the 2016 data, minimum cloud speeds of 4 ms-1 and a maximum of 40 ms-1 were obtained while dominant direction was found to be from the west-northwest. Comparison was then made to hourly wind speed and direction data recorded at 10 m above the ground level from the Bingley SAMOS weather station which is located 4 km away from the triplet of irradiance sensors. Cloud speed is invariably higher than the 10 m wind speed, on account friction between air and the earth’s surface. Nevertheless, we report a strong linear relationship between cloud speed and 10 m wind speed, with a correlation coefficient, R, of 0.9. Regarding comparison of direction, a deflection of 22.50 in the cloud direction clockwise of 10 m wind direction was observed as the dominant ground level wind direction was found to be from the west, while the dominant direction of the clouds was found to be from the west-northwest. Ramp rates were determined and compared with 10 m wind speeds. A low to moderate positive correlation were observed with a minimum and maximum correlation coefficient, R, of 0.2095 and 0.4274 in June and April respectively. These correlations are understood to have been diminished because of noise and solar irradiance reflected and focused onto the sensors by various cloud sides. This work demonstrates that both triplets of irradiance sensors and ground level wind data are useful and low-cost methods for predicting the likely frequency and magnitude of ramp rates of PV arrays

    B cells do not take up bacterial DNA: An essential role for antigen in exposure of DNA to toll-like receptor-9

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    Murine dendritic cells (DC) and macrophages respond to bacterial CpG DNA through toll-like receptor 9 (TLR9). Although it is frequently assumed that bacterial DNA is a direct stimulus for B cells, published work does not reliably show responses of purified B cells. Here we show that purified splenic B cells did not respond to Escherichia coli DNA with induction of CD86, despite readily responding to single-stranded (ss) phosphodiester CpG oligodeoxynucleotides (ODN). This was due to a combination of weak responses to both long and double-stranded (ds) DNA. B-cell DNA uptake was greatly reduced with increasing DNA length. This contrasts with macrophages where DNA uptake and subsequent responses were enhanced with increasing DNA length. However, when DNA was physically linked to hen egg lysozyme (HEL), HEL-specific B cells showed efficient uptake of DNA, and limited proliferation in response to the HEL-DNA complex. We propose that, in the absence of other signals, B cells have poor uptake and responses to long dsDNA to prevent polyclonal activation. Conversely, when DNA is physically linked to a B-cell receptor (BCR) ligand, its uptake is increased, allowing TLR9-dependent B-cell activation in an antigen-specific manner. We could not generate fragments of E. coli DNA by limited DNaseI digestion that could mimic the stimulatory effect of ss CpG ODN on naive B cells. We suggest that the frequently studied polyclonal B-cell responses to CpG ODN are relevant to therapeutic applications of phosphorothioate-modified CpG-containing ODN, but not to natural responses to foreign or host dsDNA. Immunology and Cell Biology (2011) 89, 517-525; doi:10.1038/icb.2010.112; published online 5 October 201

    Graphical Reasoning in Compact Closed Categories for Quantum Computation

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    Compact closed categories provide a foundational formalism for a variety of important domains, including quantum computation. These categories have a natural visualisation as a form of graphs. We present a formalism for equational reasoning about such graphs and develop this into a generic proof system with a fixed logical kernel for equational reasoning about compact closed categories. Automating this reasoning process is motivated by the slow and error prone nature of manual graph manipulation. A salient feature of our system is that it provides a formal and declarative account of derived results that can include `ellipses'-style notation. We illustrate the framework by instantiating it for a graphical language of quantum computation and show how this can be used to perform symbolic computation.Comment: 21 pages, 9 figures. This is the journal version of the paper published at AIS

    State of the Art Research on Sustainable Use of Water Hyacinth: A Bibliometric and Text Mining Analysis

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    This study aims to present a systematic data-driven bibliometric analysis of the water hyacinth (Eichhornia crassipes) infestation problem around the globe. As many solutions are being proposed in academia for its management, mitigation, and utilization, it requires investigation through a systematic scrutinizing lens. In this study, literature records from 1977 to June 2020 concerning research on water hyacinth are taken from Scopus for text analysis. Trends in the publication of different article types, dynamics of publication, clustering, correlation, and co-authoring patterns between different countries are observed. The cluster analysis indicated four clusters viz. (i) ecological works related to species, (ii) pollutant removal process and methods, (iii) utilization of biofuels for biogas production, and (iv) modelling works. It is clear from the networking analysis that most of the publications regarding water hyacinth are from India, followed by China and the United States. Sentiment analysis with the AFINN lexicon showed that the negative sentiment towards the aquatic weed has intensified over time. An exploratory analysis was performed using a bigram network plot, depicting and outlining different important domains of water hyacinth research. Water hyacinth research has passed the pioneering phase and is now at the end of a steady growth phase or at the beginning of an acceleration phase. In this article, an overview is given for the entirety of water hyacinth research, with an indication of future trends and possibilities

    Rationally designed dendritic silica nanoparticles for oral delivery of exenatide

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    Type 2 diabetes makes up approximately 85% of all diabetic cases and it is linked to approximately one-third of all hospitalisations. Newer therapies with long-acting biologics such as glucagon-like peptide-1 (GLP-1) analogues have been promising in managing the disease, but they cannot reverse the pathology of the disease. Additionally, their parenteral administration is often associated with high healthcare costs, risk of infections, and poor patient adherence associated with phobia of needles. Oral delivery of these compounds would significantly improve patient compliance; however, poor enzymatic stability and low permeability across the gastrointestinal tract makes this task challenging. In the present work, large pore dendritic silica nanoparticles (DSNPs) with a pore size of ~10 nm were prepared, functionalized, and optimized in order to achieve high peptide loading and improve intestinal permeation of exenatide, a GLP-1 analogue. Compared to the loading capacity of the most popular, Mobil Composition of Matter No. 41 (MCM-41) with small pores, DSNPs showed significantly high loading owing to their large and dendritic pore structure. Among the tested DSNPs, pristine and phosphonate-modified DSNPs (PDSNPs) displayed remarkable loading of 40 and 35% w/w, respectively. Furthermore, particles successfully coated with positively charged chitosan reduced the burst release of exenatide at both pH 1.2 and 6.8. Compared with free exenatide, both chitosan-coated and uncoated PDSNPs enhanced exenatide transport through the Caco-2 monolayer by 1.7 fold. Interestingly, when a triple co-culture model of intestinal permeation was used, chitosan-coated PDSNPs performed better compared to both PDSNPs and free exenatide, which corroborated our hypothesis behind using chitosan to interact with mucus and improve permeation. These results indicate the emerging role of large pore silica nanoparticles as promising platforms for oral delivery of biologics such as exenatide.We thank the National Health and Medical Research Council’s Project Grant GNT1107836 and Early Career Fellowship and Career Development Fellowship to A.P. We also thank NHMRC for EC Fellowship to T.K. We would also like to thank the Centre of Microscopy and Microanalysis at The University of Queensland for providing facilities to conduct TEM. This article was, in part, a result of the project NORTE-01-0145-FEDER-000012, supported by the Norte Portugal Regional Operational Programme (NORTE 2020), under the PORTUGAL 2020 Partnership Agreement, through the European Regional Development Fund (ERDF). This work was financed by FEDER—Fundo Europeu de Desenvolvimento Regional funds—through the COMPETE 2020–Operational Programme for Competitiveness and Internationalization (POCI), Portugal 2020, and by Portuguese funds through FCT—Fundação para a Ciência e a Tecnologia/Ministério da Ciência, Tecnologia e Ensino Superior in the framework of the project “Institute for Research and Innovation in Health Sciences” (POCI-01-0145-FEDER-007274)

    Experiences, Opportunities and Challenges of Implementing Task Shifting in Underserved Remote Settings: The Case of Kongwa District, Central Tanzania.

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    Tanzania is experiencing acute shortages of Health Workers (HWs), a situation which has forced health managers, especially in the underserved districts, to hastily cope with health workers' shortages by adopting task shifting. This has however been due to limited options for dealing with the crisis of health personnel. There are on-going discussions in the country on whether to scale up task shifting as one of the strategies for addressing health personnel crisis. However, these discussions are not backed up by rigorous scientific evidence. The aim of this paper is two-fold. Firstly, to describe the current situation of implementing task shifting in the context of acute shortages of health workers and, secondly, to provide a descriptive account of the potential opportunities or benefits and the likely challenges which might ensue as a result of implementing task shifting. We employed in-depth interviews with informants at the district level and supplemented the information with additional interviews with informants at the national level. Interviews focussed on the informants' practical experiences of implementing task shifting in their respective health facilities (district level) and their opinions regarding opportunities and challenges which might be associated with implementation of task shifting practices. At the national level, the main focus was on policy issues related to management of health personnel in the context of implementation of task shifting, in addition to seeking their opinions and perceptions regarding opportunities and challenges of implementing task shifting if formally adopted. Task shifting has been in practice for many years in Tanzania and has been perceived as an inevitable coping mechanism due to limited options for addressing health personnel shortages in the country. Majority of informants had the concern that quality of services is likely to be affected if appropriate policy infrastructures are not in place before formalising tasks shifting. There was also a perception that implementation of task shifting has ensured access to services especially in underserved remote areas. Professional discontent and challenges related to the management of health personnel policies were also perceived as important issues to consider when implementing task shifting practices. Additional resources for additional training and supervisory tasks were also considered important in the implementation of task shifting in order to make it deliver much the same way as it is for conventional modalities of delivering care. Task shifting implementation occurs as an ad hoc coping mechanism to the existing shortages of health workers in many undeserved areas of the country, not just in the study site whose findings are reported in this paper. It is recommended that the most important thing to do now is not to determine whether task shifting is possible or effective but to define the limits of task shifting so as to reach a consensus on where it can have the strongest and most sustainable impact in the delivery of quality health services. Any action towards this end needs to be evidence-based

    PPAR? Downregulation by TGF in Fibroblast and Impaired Expression and Function in Systemic Sclerosis: A Novel Mechanism for Progressive Fibrogenesis

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    The nuclear orphan receptor peroxisome proliferator-activated receptor-gamma (PPAR-γ) is expressed in multiple cell types in addition to adipocytes. Upon its activation by natural ligands such as fatty acids and eicosanoids, or by synthetic agonists such as rosiglitazone, PPAR-γ regulates adipogenesis, glucose uptake and inflammatory responses. Recent studies establish a novel role for PPAR-γ signaling as an endogenous mechanism for regulating transforming growth factor-ß (TGF-ß)- dependent fibrogenesis. Here, we sought to characterize PPAR-γ function in the prototypic fibrosing disorder systemic sclerosis (SSc), and delineate the factors governing PPAR-γ expression. We report that PPAR-γ levels were markedly diminished in skin and lung biopsies from patients with SSc, and in fibroblasts explanted from the lesional skin. In normal fibroblasts, treatment with TGF-ß resulted in a time- and dose-dependent down-regulation of PPAR-γ expression. Inhibition occurred at the transcriptional level and was mediated via canonical Smad signal transduction. Genome-wide expression profiling of SSc skin biopsies revealed a marked attenuation of PPAR-γ levels and transcriptional activity in a subset of patients with diffuse cutaneous SSc, which was correlated with the presence of a ''TGF-ß responsive gene signature'' in these biopsies. Together, these results demonstrate that the expression and function of PPAR-γ are impaired in SSc, and reveal the existence of a reciprocal inhibitory cross-talk between TGF-ß activation and PPAR-γ signaling in the context of fibrogenesis. In light of the potent anti-fibrotic effects attributed to PPAR-γ, these observations lead us to propose that excessive TGF-ß activity in SSc accounts for impaired PPAR-γ function, which in turn contributes to unchecked fibroblast activation and progressive fibrosis. © 2010 Wei et al

    Preliminary Limits on the WIMP-Nucleon Cross Section from the Cryogenic Dark Matter Search (CDMS)

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    We are conducting an experiment to search for WIMPs, or weakly-interacting massive particles, in the galactic halo using terrestrial detectors. This generic class of hypothetical particles, whose properties are similar to those predicted by extensions of the standard model of particle physics, could comprise the cold component of non-baryonic dark matter. We describe our experiment, which is based on cooled germanium and silicon detectors in a shielded low-background cryostat. The detectors achieve a high degree of background rejection through the simultaneous measurement of the energy in phonons and ionization. Using exposures on the order of one kilogram-day from initial runs of our experiment, we have achieved (preliminary) upper limits on the WIMP-nucleon cross section that are comparable to much longer runs of other experiments.Comment: 5 LaTex pages, 5 eps figs, epsf.sty, espcrc2dsa2.sty. Proceedings of TAUP97, Gran Sasso, Italy, 7-11 Sep 1997, Nucl. Phys. Suppl., A. Bottino, A. di Credico and P. Monacelli (eds.). See also http://cfpa.berkeley.ed

    MicroRNA-184 Is Induced By Store-Operated Calcium Entry And Regulates Early Keratinocyte Differentiation

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    Extracellular calcium (Ca2+) and store‐operated Ca2+ entry (SOCE) govern homoeostasis in the mammalian epidermis. Multiple microRNAs (miRNA) also regulate epidermal differentiation, and raised external Ca2+ modulates the expression of several such miRNAs in keratinocytes. However, little is known about the regulation of miR‐184 in keratinocytes or the roles of miR‐184 in keratinocyte differentiation. Here we report that exogenous Ca2+ stimulates miR‐184 expression in primary epidermal keratinocytes and that this occurs in a SOCE‐dependent manner. Levels of miR‐184 were raised by about 30‐fold after exposure to 1.5 mM Ca2+ for 5 days. In contrast, neither phorbol ester nor 1,25‐dihydroxyvitamin D3 had any effect on miR‐184 levels. Pharmacologic and genetic inhibitors of SOCE abrogated Ca2+‐dependent miR‐184 induction by 70% or more. Ectopic miR‐184 inhibited keratinocyte proliferation and led to a fourfold increase in the expression of involucrin, a marker of early keratinocyte differentiation. Exogenous miR‐184 also triggered a threefold rise in levels of cyclin E and doubled the levels of γH2AX, a marker of DNA double‐strand breaks. The p21 cyclin‐dependent kinase inhibitor, which supports keratinocyte growth arrest, was also induced by miR‐184. Together our findings point to an SOCE:miR‐184 pathway that targets a cyclin E/DNA damage regulatory node to facilitate keratinocyte differentiation

    Health worker performance in the management of paediatric fevers following in-service training and exposure to job aids in Kenya

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    BACKGROUND: Improving the way artemether-lumefantrine (AL) is provided to patients attending clinics is critical to maximize the benefit of this new medicine. In 2007, a new initiative was launched in one part of Kenya to improve malaria case-management through enhanced in-service training and provision of job aids. METHODS: An evaluation of the intervention using pre- and post-intervention cross sectional health facility surveys was conducted in Bondo district. The surveys included: audit of government health facilities, health worker structured interviews and exit interviews with caretakers of sick children below five years of age. The outcome indicators were the proportions of febrile children who had AL prescribed, AL dispensed, and four different dispensing and counseling tasks performed. RESULTS: At baseline 33 government health facilities, 48 health workers and 386 febrile child consultations were evaluated. At follow-up the same health facilities were surveyed and 36 health workers and 390 febrile child consultations evaluated. The findings show: 1) no health facility or health worker was exposed to all components of the intervention; 2) the proportion of health workers who received the enhanced in-service training was 67%; 3) the proportion of febrile children with uncomplicated malaria treated with the first-line anti-malarial drug, artemether-lumefantrine (AL), at health facilities where AL was in stock increased from 76.9% (95%CI: 69.4, 83.1) to 87.6% (95% CI: 82.5, 91.5); 4) there were modest but non-significant improvements in dispensing and counseling practices; and 5) when the analyses were restricted to health workers who received the enhanced in-service training and/or had received new guidelines and job aids, no significant improvements in reported case-management tasks were observed compared to baseline. CONCLUSION: In-service training and provision of job aids alone may not be adequate to improve the prescribing, dispensing and counseling tasks necessary to change malaria case-management practices and the inclusion of supervision and post-training follow-up should be considered in future clinical practice change initiatives
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