274 research outputs found

    Thermophoresis effects on non-Darcy MHD mixed convective heat and mass transfer past a porous wedge in the presence of suction/injection

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    An analysis is presented to investigate the effect of thermophoresis particle deposition and variable viscosity on non-Darcy MHD mixed convective heat and mass transfer of a viscous, incompressible and electrically conducting fluid past a porous wedge in the presence of suction/injection. The wall of the wedge is embedded in a uniform non-Darcian porous medium in order to allow for possible fluid wall suction or injection. The governing partial differential equations of the problem, subjected to their boundary conditions, are solved numerically by applying an efficient solution scheme for local nonsimilarity boundary layer analysis. Numerical calculations are carried out for different values of dimensionless parameter in the problem and an analysis of the results obtained show that the flow field is influenced appreciably by the applied magnetic field. The results are compared with those known from the literature and excellent agreement between the results is obtained

    Investigating hookworm genomes by comparative analysis of two Ancylostoma species

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    Background Hookworms, infecting over one billion people, are the mostly closely related major human parasites to the model nematode Caenorhabditis elegans. Applying genomics techniques to these species, we analyzed 3,840 and 3,149 genes from Ancylostoma caninum and A. ceylanicum. Results Transcripts originated from libraries representing infective L3 larva, stimulated L3, arrested L3, and adults. Most genes are represented in single stages including abundant transcripts like hsp-20 in infective L3 and vit-3 in adults. Over 80% of the genes have homologs in C. elegans, and nearly 30% of these were with observable RNA interference phenotypes. Homologies were identified to nematode-specific and clade V specific gene families. To study the evolution of hookworm genes, 574 A. caninum / A. ceylanicum orthologs were identified, all of which were found to be under purifying selection with distribution ratios of nonsynonymous to synonymous amino acid substitutions similar to that reported for C. elegans / C. briggsae orthologs. The phylogenetic distance between A. caninum and A. ceylanicum is almost identical to that for C. elegans / C. briggsae. Conclusion The genes discovered should substantially accelerate research toward better understanding of the parasites' basic biology as well as new therapies including vaccines and novel anthelmintics

    Elucidating the role of Staphylococcus epidermidis serine-aspartate repeat protein G in platelet activation.

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    BACKGROUND: Staphylococcus epidermidis is a commensal of the human skin that has been implicated in infective endocarditis and infections involving implanted medical devices. S. epidermidis induces platelet aggregation by an unknown mechanism. The fibrinogen-binding protein serine-aspartate repeat protein G (SdrG) is present in 67-91% of clinical strains. OBJECTIVES: To determine whether SdrG plays a role in platelet activation, and if so to investigate the role of fibrinogen in this mechanism. METHODS: SdrG was expressed in a surrogate host, Lactococcus lactis, in order to investigate its role in the absence of other staphylococcal components. Platelet adhesion and platelet aggregation assays were employed. RESULTS: L. lactis expressing SdrG stimulated platelet aggregation (lag time: 2.9 +/- 0.5 min), whereas the L. lactis control did not. L. lactis SdrG-induced aggregation was inhibited by alpha(IIb)beta3 antagonists and aspirin. Aggregation was dependent on both fibrinogen and IgG, and the platelet IgG receptor FcgammaRIIa. Preincubation of the bacteria with Bbeta-chain fibrinopeptide inhibited aggregation (delaying the lag time six-fold), suggesting that fibrinogen acts as a bridging molecule. Platelets adhered to L. lactis SdrG in the absence of fibrinogen. Adhesion was inhibited by alpha(IIb)beta3 antagonists, suggesting that this direct interaction involves alpha(IIb)beta3. Investigation using purified fragments of SdrG revealed a direct interaction with the B-domains. Adhesion to the A-domain involved both a fibrinogen and an IgG bridge. CONCLUSION: SdrG alone is sufficient to support platelet adhesion and aggregation through both direct and indirect mechanisms

    Highly Sensitive Portable Liquid Petroleum Gas Leakage Detector

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    A simple, low cost and portable handheld liquid petroleum gas detector is reported in this paper. This battery powered handheld device is fitted with an MQ2 gas sensor and the output voltage of the sensor varies in accordance with the concentration of the gas in the surrounding. The sensor is connected to a microprocessor to display the output and produce an alarm when gas leakage is detected. The concentration of the gas present in the atmosphere is measured and displayed with a detection limit of 50 ppm. The sensor demonstrated high sensitivity towards gas leakages with the response and recovery times of 5 seconds and 8 seconds respectively

    Comparison of architect assay and elecsys HBs Ag II assay in the quantification of hepatitis B surface antigen in chronic HBV patients

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    Background. Hepatitis B virus (HBV) infection is a global health concern, with an estimated 296 million chronic carriers worldwide. Quantification of hepatitis B surface antigen (HBsAg) is a crucial tool in HBV disease management, providing valuable insights into disease progression and treatment efficacy. Objective. To evaluate the comparative performance of the Abbott Architect HBsAg QT and Roche Elecsys HBsAg II assays in quantifying hepatitis B surface antigen (HBsAg) levels in patients with chronic hepatitis B (CHB). Methods. This prospective study enrolled 60 confirmed CHB patients between February 2021 and November 2021. HBsAg levels were measured using both assays and subsequently log-transformed (log10 IU/mL) for statistical analysis. Interclass correlation coefficient (ICC), Pearson correlation coefficient, and Bland-Altman analyses were employed to assess assay concordance and systematic bias. Results. A statistically significant positive correlation was observed between the Elecsys HBsAg II and Architect HBsAg QT assays for both untreated and treatment-receiving CHB patients (ICC values not specified, p <0.001). Notably, Architect consistently yielded higher HBsAg measurements compared to Elecsys. Conclusion. Both the Elecsys HBsAg II and Architect HBsAg QT assays demonstrate robust correlation in quantifying HBsAg levels in CHB patients. However, the Architect assay exhibits a systematic positive bias relative to Elecsys, which should be considered when interpreting results and making clinical decisions. Both tools provide reliable assessments for HBsAg quantification within CHB management strategies, but it is essential to be aware of potential assay-specific differences

    On correctness in RDF stream processor benchmarking

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    Two complementary benchmarks have been proposed so far for the evaluation and continuous improvement of RDF stream processors: SRBench and LSBench. They put a special focus on different features of the evaluated systems, including coverage of the streaming extensions of SPARQL supported by each processor, query processing throughput, and an early analysis of query evaluation correctness, based on comparing the results obtained by different processors for a set of queries. However, none of them has analysed the operational semantics of these processors in order to assess the correctness of query evaluation results. In this paper, we propose a characterization of the operational semantics of RDF stream processors, adapting well-known models used in the stream processing engine community: CQL and SECRET. Through this formalization, we address correctness in RDF stream processor benchmarks, allowing to determine the multiple answers that systems should provide. Finally, we present CSRBench, an extension of SRBench to address query result correctness verification using an automatic method

    SRBench: A streaming RDF/SPARQL benchmark

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    We introduce SRBench, a general-purpose benchmark primarily designed for streaming RDF/SPARQL engines, completely based on real-world data sets from the Linked Open Data cloud. With the increasing problem of too much streaming data but not enough tools to gain knowledge from them, researchers have set out for solutions in which Semantic Web technologies are adapted and extended for publishing, sharing, analysing and understanding streaming data. To help researchers and users comparing streaming RDF/SPARQL (strRS) engines in a standardised application scenario, we have designed SRBench, with which one can assess the abilities of a strRS engine to cope with a broad range of use cases typically encountered in real-world scenarios. The data sets used in the benchmark have been carefully chosen, such that they represent a realistic and relevant usage of streaming data. The benchmark defines a concise, yet omprehensive set of queries that cover the major aspects of strRS processing. Finally, our work is complemented with a functional evaluation on three representative strRS engines: SPARQLStream, C-SPARQL and CQELS. The presented results are meant to give a first baseline and illustrate the state-of-the-art
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