310 research outputs found

    Performance of locally developed sunflower (Helianthus annuus L.) hybrids under irrigation

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        A field experiment was carried out at two locations, New Halfa and Rahad, for two cropping seasons, summer (2003/04) and winter (2004/05) at each location in a randomized complete block design with four replicates, to estimate the phenotypic and genotypic variability, heritability in broad sense and genetic advance for yield, yield components and other agronomic characters among 20 locally developed sunflower (Helianthus annuus L.) hybrids. Highly significant differences found between the evaluated hybrids for almost all characters at the four environments, except plant height at New Halfa, in summer, 1000- seed weight and seed yield at both locations in winter. Most of the variation for the morphological traits was due to genetic factors, whereas, the variation in yield and its components was due to environmental factors. High heritability estimate (>60 %) coupled with low genetic advance for the morphological characters indicate epistatic and dominance nature of inheritance, while, the low heritability (<60 %) coupled with high genetic advance for yield and its components, would indicate additive nature of inheritance. Therefore, direct selection for the morpholo-gical traits, based on the phenotype, among the hybrids may be effective, while selection for yield and yield components may not be effective. Thus, there is a need for a mechanism, other than simple selection, to improve yield in sunflower

    Efficiency Increase and Fuel Save Benefits of Combined Cycle Operation (Garri Power Plant as a Case Study)

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    Thermal power plants’ overall efficiency increase, and fuel consumption decrease draw worldwide researcher’s attention due to the limited resources and high cost of fossil fuel. Considering Al-Jaily power plant, the so-called Garri power plants 1 and 2 in Sudan as the case study, this paper compares overall plant efficiency and fuel save with the combined cycle and open cycle operation in which both plants could run. Evaluation of plant’s efficiency is based on the first law of thermodynamics. The results reveal advantage of the combined cycle operation mode in terms of efficiency increase, and on the other hand, in terms of fuel consumption decrease with the same amount of energy produced

    Production of sensitive gas sensors using CuO/SnO2 nanoparticles

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    Metal oxide nanoparticles, such as CuO and SnO2, are outstanding systems for H2S gas sensing in air. In this work, those nanoparticles were deposited with different mixing percentages on substrates to form percolating networks of nanoparticles. Electrical electrodes were deposited on the nanoparticles’ films to investigate their gas sensing response against H2 and H2S, and their electrical characteristics. The sensor devices based on CuO–SnO2 nanoparticles revealed enhanced sensing characteristics against H2S with a sensitivity of 10 ppm. The enhanced sensing characteristics could be attributed to the formation of PN-junctions among CuO and SnO2 nanoparticles. The reasonable production cost (due to simple structure and cheap used materials), low power consumption ( ~ 1 µW for H2S at room temperature), high sensitivity, high response, and reasonable response time of the present sensors qualify them for practical implementation in portable gas sensing devices with enhanced characteristics.Open Access funding provided by the Qatar National Library. This work was supported by both Qatar National Research Fund (QNRF) under a Grant Number UREP21-035-2-013, and Qatar University fund under a Grant Number QUCG-CAS-20182019-1. The SEM/EDS measurements were accomplished in the Central Laboratories unit at Qatar University. Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations

    Electrical performance of efficient quad-crescent-shaped Si nanowire solar cell

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    The electrical characteristics of quad-crescent-shaped silicon nanowire (NW) solar cells (SCs) are numerically analyzed and as a result their performance optimized. The structure discussed consists of four crescents, forming a cavity that permits multiple light scattering with high trapping between the NWs. Additionally, new modes strongly coupled to the incident light are generated along the NWs. As a result, the optical absorption has been increased over a large portion of light wavelengths and hence the power conversion efficiency (PCE) has been improved. The electron–hole (e–h) generation rate in the design reported has been calculated using the 3D finite difference time domain method. Further, the electrical performance of the SC reported has been investigated through the finite element method, using the Lumerical charge software package. In this investigation, the axial and core–shell junctions were analyzed looking at the reported crescent and, as well, conventional NW designs. Additionally, the doping concentration and NW-junction position were studied in this design proposed, as well as the carrier-recombination-and-lifetime effects. This study has revealed that the high back surface field layer used improves the conversion efficiency by ∼ 80%. Moreover, conserving the NW radial shell as a low thickness layer can efficiently reduce the NW sidewall recombination effect. The PCE and short circuit current were determined to be equal to 18.5% and 33.8 mA/cm2^{2} for the axial junction proposed. However, the core–shell junction shows figures of 19% and 34.9 mA/cm2^{2}. The suggested crescent design offers an enhancement of 23% compared to the conventional NW, for both junctions. For a practical surface recombination velocity of 102^{2} cm/s, the PCE of the proposed design, in the axial junction, has been reduced to 16.6%, with a reduction of 11%. However, the core–shell junction achieves PCE of 18.7%, with a slight reduction of 1.6%. Therefore, the optoelectronic performance of the core–shell junction was marginally affected by the NW surface recombination, compared to the axial junction

    Production of extracellular alkaline protease by new halotolerant alkaliphilic Bacillus sp. NPST-AK15 isolated from hyper saline soda lakes

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    Background: Alkaline proteases are among the most important classes of industrial hydrolytic enzymes. The industrial demand for alkaline proteases with favorable properties continues to enhance the search for new enzymes. The present study focused on isolation of new alkaline producing alkaliphilic bacteria from hyper saline soda lakes and optimization of the enzyme production. Results: A new potent alkaline protease producing halotolerant alkaliphilic isolate NPST-AK15 was isolated from hyper saline soda lakes, which affiliated to Bacillus sp. based on 16S rRNA gene analysis. Organic nitrogen supported enzyme production showing maximum yield using yeast extract, and as a carbon source, fructose gave maximum protease production. NPST-AK15 can grow over a broad range of NaCl concentrations (0\u201320%), showing maximal growth and enzyme production at 0\u20135%, indicated the halotolerant nature of this bacterium. Ba and Ca enhanced enzyme production by 1.6 and 1.3 fold respectively. The optimum temperature and pH for both enzyme production and cell growth were at 40\ub0C and pH 11, respectively. Alkaline protease secretion was coherent with the growth pattern, started at beginning of the exponential phase and reached maximal in mid stationary phase (36 h). Conclusions: A newhalotolerant alkaliphilic alkaline protease producing Bacillus sp.NPST-AK15 was isolated from soda lakes. Optimization of various fermentation parameters resulted in an increase of enzyme yield by 22.8 fold, indicating the significance of optimization of the fermentation parameters to obtain commercial yield of the enzyme. NPST-AK15 and its extracellular alkaline protease with salt tolerance signify their potential applicability in the laundry industry and other applications

    Consensus evidence-based recommendations for treat-to-target management of immunoglobulin A vasculitis

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    IgA vasculitis (IgAV), formerly known as Henoch-Schönlein purpura, is the most common cause of systemic vasculitis in childhood. Given its potential life-threatening systemic complications, early and accurate diagnosis as well as management of IgAV represent a major challenge for health care professionals. This study was carried out to attain an evidence-based expert consensus on a treat-to-target management approach for IgAV using Delphi technique. The preliminary scientific committee identified a total of 16 key clinical questions according to the patient, intervention, comparison, and outcomes (PICO) approach. An evidence-based, systematic, literature review was conducted to compile evidence for the IgAV management. The core leadership team identified researchers and clinicians with expertise in IgAV management in Egypt upon which experts were gathered from different governorates and health centers across Egypt. Delphi process was implemented (two rounds) to reach a consensus. An online questionnaire was sent to expert panel (n = 26) who participated in the two rounds. After completing round 2, a total of 20 recommendation items, categorized into two sections were obtained. Agreement with the recommendations (rank 7–9) ranged from 91.7–100%. Consensus was reached (i.e. ⩾75% of respondents strongly agreed or agreed) on the wording of all the 20 clinical standards identified by the scientific committee. Algorithms for the diagnosis and management have been suggested. This was an expert, consensus recommendations for the diagnosis and treatment of IgAV and IgA vasculitic nephritis, based on best available evidence and expert opinion. The guideline presented a strategy of care with a pathway to achieve a state of remission as early as possible

    The ENIGMA Stroke Recovery Working Group: Big data neuroimaging to study brain–behavior relationships after stroke

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    The goal of the Enhancing Neuroimaging Genetics through Meta‐Analysis (ENIGMA) Stroke Recovery working group is to understand brain and behavior relationships using well‐powered meta‐ and mega‐analytic approaches. ENIGMA Stroke Recovery has data from over 2,100 stroke patients collected across 39 research studies and 10 countries around the world, comprising the largest multisite retrospective stroke data collaboration to date. This article outlines the efforts taken by the ENIGMA Stroke Recovery working group to develop neuroinformatics protocols and methods to manage multisite stroke brain magnetic resonance imaging, behavioral and demographics data. Specifically, the processes for scalable data intake and preprocessing, multisite data harmonization, and large‐scale stroke lesion analysis are described, and challenges unique to this type of big data collaboration in stroke research are discussed. Finally, future directions and limitations, as well as recommendations for improved data harmonization through prospective data collection and data management, are provided

    Anti-PD-1 immunotherapy leads to tuberculosis reactivation via dysregulation of TNF-alpha

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    Previously, we developed a 3-dimensional cell culture model of human tuberculosis (TB) and demonstrated its potential to interrogate the host-pathogen interaction (Tezera et al., 2017a). Here, we use the model to investigate mechanisms whereby immune checkpoint therapy for cancer paradoxically activates TB infection. In patients, PD-1 is expressed in Mycobacterium tuberculosis (Mtb)-infected lung tissue but is absent in areas of immunopathology. In the microsphere model, PD-1 ligands are up-regulated by infection, and the PD-1/PD-L1 axis is further induced by hypoxia. Inhibition of PD-1 signalling increases Mtb growth, and augments cytokine secretion. TNF-a is responsible for accelerated Mtb growth, and TNF-a neutralisation reverses augmented Mtb growth caused by anti-PD-1 treatment. In human TB, pulmonary TNF-a immunoreactivity is increased and circulating PD-1 expression negatively correlates with sputum TNF-a concentrations. Together, our findings demonstrate that PD-1 regulates the immune response in TB, and inhibition of PD-1 accelerates Mtb growth via excessive TNF-a secretion.</p

    Antimicrobial resistance among migrants in Europe: a systematic review and meta-analysis

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    BACKGROUND: Rates of antimicrobial resistance (AMR) are rising globally and there is concern that increased migration is contributing to the burden of antibiotic resistance in Europe. However, the effect of migration on the burden of AMR in Europe has not yet been comprehensively examined. Therefore, we did a systematic review and meta-analysis to identify and synthesise data for AMR carriage or infection in migrants to Europe to examine differences in patterns of AMR across migrant groups and in different settings. METHODS: For this systematic review and meta-analysis, we searched MEDLINE, Embase, PubMed, and Scopus with no language restrictions from Jan 1, 2000, to Jan 18, 2017, for primary data from observational studies reporting antibacterial resistance in common bacterial pathogens among migrants to 21 European Union-15 and European Economic Area countries. To be eligible for inclusion, studies had to report data on carriage or infection with laboratory-confirmed antibiotic-resistant organisms in migrant populations. We extracted data from eligible studies and assessed quality using piloted, standardised forms. We did not examine drug resistance in tuberculosis and excluded articles solely reporting on this parameter. We also excluded articles in which migrant status was determined by ethnicity, country of birth of participants' parents, or was not defined, and articles in which data were not disaggregated by migrant status. Outcomes were carriage of or infection with antibiotic-resistant organisms. We used random-effects models to calculate the pooled prevalence of each outcome. The study protocol is registered with PROSPERO, number CRD42016043681. FINDINGS: We identified 2274 articles, of which 23 observational studies reporting on antibiotic resistance in 2319 migrants were included. The pooled prevalence of any AMR carriage or AMR infection in migrants was 25·4% (95% CI 19·1-31·8; I2 =98%), including meticillin-resistant Staphylococcus aureus (7·8%, 4·8-10·7; I2 =92%) and antibiotic-resistant Gram-negative bacteria (27·2%, 17·6-36·8; I2 =94%). The pooled prevalence of any AMR carriage or infection was higher in refugees and asylum seekers (33·0%, 18·3-47·6; I2 =98%) than in other migrant groups (6·6%, 1·8-11·3; I2 =92%). The pooled prevalence of antibiotic-resistant organisms was slightly higher in high-migrant community settings (33·1%, 11·1-55·1; I2 =96%) than in migrants in hospitals (24·3%, 16·1-32·6; I2 =98%). We did not find evidence of high rates of transmission of AMR from migrant to host populations. INTERPRETATION: Migrants are exposed to conditions favouring the emergence of drug resistance during transit and in host countries in Europe. Increased antibiotic resistance among refugees and asylum seekers and in high-migrant community settings (such as refugee camps and detention facilities) highlights the need for improved living conditions, access to health care, and initiatives to facilitate detection of and appropriate high-quality treatment for antibiotic-resistant infections during transit and in host countries. Protocols for the prevention and control of infection and for antibiotic surveillance need to be integrated in all aspects of health care, which should be accessible for all migrant groups, and should target determinants of AMR before, during, and after migration. FUNDING: UK National Institute for Health Research Imperial Biomedical Research Centre, Imperial College Healthcare Charity, the Wellcome Trust, and UK National Institute for Health Research Health Protection Research Unit in Healthcare-associated Infections and Antimictobial Resistance at Imperial College London
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