304 research outputs found

    Numerical and experimental investigation of an Archimedes screw turbine for open channel water flow application

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    AbstractLow‐head turbines are becoming an agricultural imperative due to their high efficiency, low cost, ability to operate at low flow rates and minimal environmental impact. Therefore, the Archimedes screw turbine (AST) can play a leading role for producing electric power, especially in Pakistan's rural areas where most of the places have less than 1 m head. In this research work, performance evaluation of AST was carried out at different flow velocities in terms of power coefficient and torque generated. Design parameters such as blade width, blade pitches, and blade rotational angles are also used for performance evaluation. For this purpose, computational fluid dynamic (CFD) analyses of AST blades were conducted at different water flow velocities (e.g., 1, 1.5, 2, 2.5, 3, and 3.5 m/s). ANSYS FLUENT was used for AST blade simulations using three different design parameters such as blade width, blade pitch, and blade rotational angles. Additionally, CFD simulations have inherent errors and uncertainties that may lead to findings and deviations from their exact or real values. To prevent these uncertainties and errors, an experimental study was also conducted to provide validation for the CFD simulation results. The results revealed from CFD simulations for optimized design parameters were then compared with experimental data. From the results, it was examined that the numerical findings were in good agreement with the experiment data. The highest power coefficient and power output values were obtained under optimized design parameters such as inner and outer diameter, blade pitch, blade width, blade rotation angles and shaft length (e.g., 40 mm, 120 mm, 130 mm, 2 mm, 60°, and 850 mm respectively). The findings can be useful to implement the AST unit for those places where the available water head is ranging from 1 to 6.5 m and a flow rate of 0.2–6.5 m3/s, especially for rural areas of Pakistan

    Comparative correlation and path analysis in local and exotic germplasm in lentil

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    Two sets of germplasm, one of local collection and another of introduced lines comprising 89 and 50 lines respectively were evaluated in 1980–81 and in 1981–82 respectively. Correlation coefficients among various characters as well as path analysis of five characters were estimated for the both sets of germplasm. Seed yield was found to have high positive correlation with pods/plant, primary and secondary branches in both sets of germplasm. Seed weight did not show any relationship with yield in the local germplasm but showed high positive association with yield in the exotic germplasm. Pods/plant was found to have high positive correlation with primary and secondary branches. In both sets of germplasm, pods/plant had high direct effect da seed yield, but only in the exotic germplasm, pods/plant had high direct effect on seed yield, but only in the exotic germplasm 100-seed weight had high direct effect on seed yield. Secondary branches had no direct effect on seed, but its indirect effect through pods/plant was high

    Enhancement of Penaeus monodon shrimp postlarvae growth and survival without water exchange using marine Bacillus pumilus and periphytic microalgae.

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    We have investigated the possibility of using a consortium of marine bacterium and periphytic microalgae to improve the water quality and increase the growth and survival of the shrimp Penaeus monodon in a hatchery system. Three treatments were evaluated for their effect on P. monodon postlarvae (PL) when the culture water was not changed: Bacillus pumilus alone (B); periphytic microalgae alone (M); B. pumilus + periphytic microalgae (BM). P. monodon PL raised in a tank of unchanged water without bacterium and periphytic microalgae served as the control. The water in tanks of the M and BM treatments had significantly low levels of total ammonia-nitrogen (TAN) (0.03 and 0.01 mg l−1, respectively) and nitrite-nitrogen (NO2-N) (0.03, 0.01 mg l−1, respectively) than that in the B (TAN 0.80, NO2-N 0.68 mg l−1) and control (TAN 1.11, NO2-N 1.12 mg l−1) tanks. Moreover, PL cultured in tanks M and BM had significantly higher survival and specific growth rates and a significantly higher resistance to the reverse salinity stress test than those in the B and control tanks. Compared to the control PL, the PL cultured in the BM tanks had significantly higher levels of protein, lipid, polyunsaturated fatty acids, ecosapentaenoic acid, and docosahexaenoic acid. The culture water in tanks BM also contained significantly less Vibrio than the control water. Our results illustrate the beneficial effects of a B. pumilus and periphytic microalgae consortium on improving the water quality and the growth and survival of shrimp PL grown in a hatchery system

    Approaches to improving breast screening uptake: evidence and experience from Tower Hamlets

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    This paper reports on an innovative whole-systems approach to improving uptake of breast screening in Tower Hamlets, a deprived borough in the East End of London with a large minority ethnic population. The approach, developed by the public health team at NHS Tower Hamlets, draws on analysis of needs and existing literature about effective interventions to promote breast screening. Social marketing research led to a campaign targeted at Bangladeshi women, together with a range of initiatives to promote breast screening through primary care services and community outreach through local well-known organisations. The breast screening service itself was upgraded and a new service specification is being introduced from April 2009

    Evaluation of a service intervention to improve awareness and uptake of bowel cancer screening in ethnically-diverse areas

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    The Policy Research Unit in Cancer Awareness, Screening and Early Diagnosis receives funding for a research programme from the UK Department of Health Policy Research Programme (grant no. 106/0001). It is a collaboration between researchers from seven institutions (the Queen Mary University of London, the UCL, the King’s College London, the London School of Hygiene and Tropical Medicine, the Hull York Medical School, the Durham University and the Peninsula Medical School)

    Scale-up and large-scale production of Tetraselmis sp CTP4 (Chlorophyta) for CO2 mitigation: from an agar plate to 100-m(3) industrial photobioreactors

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    Industrial production of novel microalgal isolates is key to improving the current portfolio of available strains that are able to grow in large-scale production systems for different biotechnological applications, including carbon mitigation. In this context, Tetraselmis sp. CTP4 was successfully scaled up from an agar plate to 35-and 100-m(3) industrial scale tubular photobioreactors (PBR). Growth was performed semi-continuously for 60 days in the autumn-winter season (17th October -14th December). Optimisation of tubular PBR operations showed that improved productivities were obtained at a culture velocity of 0.65-1.35 m s(-1) and a pH set-point for CO2 injection of 8.0. Highest volumetric (0.08 +/- 0.01 g L-1 d(-1)) and areal (20.3 +/- 3.2 g m(-2) d(-1)) biomass productivities were attained in the 100-m(3) PBR compared to those of the 35-m(3) PBR (0.05 +/- 0.02 g L-1 d(-1) and 13.5 +/- 4.3 g m(-2) d(-1), respectively). Lipid contents were similar in both PBRs (9-10% of ash free dry weight). CO2 sequestration was followed in the 100-m(3) PBR, revealing a mean CO2 mitigation efficiency of 65% and a biomass to carbon ratio of 1.80. Tetraselmis sp. CTP4 is thus a robust candidate for industrial-scale production with promising biomass productivities and photosynthetic efficiencies up to 3.5% of total solar irradiance.Portuguese national budget; Foundation for Science and Technology (FCT) [CCMAR/Multi/04326/2013]; INTERREG V-A Espana-Portugal project [0055 ALGARED + 5 E]; COST Action - European Network for Bio-products [1408]; FCT [SFRH/BD/105541/2014]; Nord Universityinfo:eu-repo/semantics/publishedVersio

    Molecular surveillance of Plasmodium vivax dhfr and dhps mutations in isolates from Afghanistan

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    <p>Abstract</p> <p>Background</p> <p>Analysis of dihydrofolate reductase (<it>dhfr</it>) and dihydropteroate synthase (<it>dhps</it>) mutations in <it>Plasmodium vivax </it>wild isolates has been considered to be a valuable molecular approach for mapping resistance to sulphadoxine-pyrimethamine (SP). The present study investigates the frequency of SNPs-haplotypes in the <it>dhfr </it>and <it>dhps </it>genes in <it>P. vivax </it>clinical isolates circulating in two malaria endemic areas in Afghanistan.</p> <p>Methods</p> <p><it>P. vivax </it>clinical isolates (n = 171) were collected in two different malaria endemic regions in north-west (Herat) and east (Nangarhar) Afghanistan in 2008. All collected isolates were analysed for SNP-haplotypes at positions 13, 33, 57, 58, 61, 117 and 173 of the <it>pvdhfr </it>and 383 and 553 of the <it>pvdhps </it>genes using PCR-RFLP methods.</p> <p>Results</p> <p>All 171 examined isolates were found to carry wild-type amino acids at positions 13, 33, 57, 61 and 173, while 58R and 117N mutations were detected among 4.1% and 12.3% of Afghan isolates, respectively. Based on the size polymorphism of <it>pvdhfr </it>genes at repeat region, type B was the most prevalent variant among Herat (86%) and Nangarhar (88.4%) isolates. Mixed genotype infections (type A/B and A/B/C) were detected in only 2.3% (2/86) of Herat and 1.2% (1/86) of Nangarhar isolates, respectively. The combination of <it>pvdhfr </it>and <it>pvdhps </it>haplotypes among all 171 samples demonstrated six distinct haplotypes. The two most prevalent haplotypes among all examined samples were wild-type (86%) and single mutant haplotype I<sub>13</sub>P<sub>33</sub>F<sub>57</sub>S<sub>58</sub>T<sub>61</sub><b>N </b><sub>117</sub>I<sub>173/</sub>A<sub>383</sub>A<sub>553 </sub>(6.4%).</p> <p>Double (I<sub>13</sub>P<sub>33</sub>S<sub>57</sub><b>R</b><sub>58</sub>T<sub>61</sub><b>N</b><sub>117</sub>I<sub>173</sub>/A<sub>383</sub>A<sub>553</sub>) and triple mutant haplotypes (I<sub>13</sub>P<sub>33</sub>S<sub>57</sub><b>R </b><sub>58</sub>T<sub>61</sub><b>N</b><sub>117</sub>I<sub>173</sub>/<b>G</b><sub>383</sub>A<sub>553</sub>) were found in 1.7% and 1.2% of Afghan isolates, respectively. This triple mutant haplotype was only detected in isolates from Herat, but in none of the Nangarhar isolates.</p> <p>Conclusion</p> <p>The present study shows a limited polymorphism in <it>pvdhfr </it>from Afghan isolates and provides important basic information to establish an epidemiological map of drug-resistant vivax malaria, and updating guidelines for anti-malarial policy in Afghanistan. The continuous usage of SP as first-line anti-malarial drug in Afghanistan might increase the risk of mutations in the <it>dhfr </it>and <it>dhps </it>genes in both <it>P. vivax </it>and <it>Plasmodium falciparum </it>isolates, which may lead to a complete SP resistance in the near future in this region. Therefore, continuous surveillance of <it>P. vivax </it>and <it>P. falciparum </it>molecular markers are needed to monitor the development of resistance to SP in the region.</p

    A Protein Phosphorylation Threshold for Functional Stacking of Plant Photosynthetic Membranes

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    Phosphorylation of photosystem II (PSII) proteins affects macroscopic structure of thylakoid photosynthetic membranes in chloroplasts of the model plant Arabidopsis. In this study, light-scattering spectroscopy revealed that stacking of thylakoids isolated from wild type Arabidopsis and the mutant lacking STN7 protein kinase was highly influenced by cation (Mg++) concentrations. The stacking of thylakoids from the stn8 and stn7stn8 mutants, deficient in STN8 kinase and consequently in light-dependent phosphorylation of PSII, was increased even in the absence of Mg++. Additional PSII protein phosphorylation in wild type plants exposed to high light enhanced Mg++-dependence of thylakoid stacking. Protein phosphorylation in the plant leaves was analyzed during day, night and prolonged darkness using three independent techniques: immunoblotting with anti-phosphothreonine antibodies; Diamond ProQ phosphoprotein staining; and quantitative mass spectrometry of peptides released from the thylakoid membranes by trypsin. All assays revealed dark/night-induced increase in phosphorylation of the 43 kDa chlorophyll-binding protein CP43, which compensated for decrease in phosphorylation of the other PSII proteins in wild type and stn7, but not in the stn8 and stn7stn8 mutants. Quantitative mass spectrometry determined that every PSII in wild type and stn7 contained on average 2.5±0.1 or 1.4±0.1 phosphoryl groups during day or night, correspondingly, while less than every second PSII had a phosphoryl group in stn8 and stn7stn8. It is postulated that functional cation-dependent stacking of plant thylakoid membranes requires at least one phosphoryl group per PSII, and increased phosphorylation of PSII in plants exposed to high light enhances stacking dynamics of the photosynthetic membranes

    Defining Plasmodium falciparum Treatment in South West Asia: A Randomized Trial Comparing Artesunate or Primaquine Combined with Chloroquine or SP

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    INTRODUCTION: Antimalarial resistance has led to a global policy of artemisinin-based combination therapy. Despite growing resistance chloroquine (CQ) remained until recently the official first-line treatment for falciparum malaria in Pakistan, with sulfadoxine-pyrimethamine (SP) second-line. Co-treatment with the gametocytocidal primaquine (PQ) is recommended for transmission control in South Asia. The relative effect of artesunate (AS) or primaquine, as partner drugs, on clinical outcomes and gametocyte carriage in this setting were unknown. METHODS: A single-blinded, randomized trial among Afghan refugees in Pakistan compared six treatment arms: CQ; CQ+(single-dose)PQ; CQ+(3 d)AS; SP; SP+(single-dose)PQ, and SP+(3 d)AS. The objectives were to compare treatment failure rates and effect on gametocyte carriage, of CQ or SP monotherapy against the respective combinations (PQ or AS). Outcomes included trophozoite and gametocyte clearance (read by light microscopy), and clinical and parasitological failure. FINDINGS: A total of 308 (87%) patients completed the trial. Failure rates by day 28 were: CQ 55/68 (81%); CQ+AS 19/67 (28%), SP 4/41 (9.8%), SP+AS 1/41 (2.4%). The addition of PQ to CQ or SP did not affect failure rates (CQ+PQ 49/67 (73%) failed; SP+PQ 5/33 (16%) failed). AS was superior to PQ at clearing gametocytes; gametocytes were seen on d7 in 85% of CQ, 40% of CQ+PQ, 21% of CQ+AS, 91% of SP, 76% of SP+PQ and 23% of SP+AS treated patients. PQ was more effective at clearing older gametocyte infections whereas AS was more effective at preventing emergence of mature gametocytes, except in cases that recrudesced. CONCLUSIONS: CQ is no longer appropriate by itself or in combination. These findings influenced the replacement of CQ with SP+AS for first-line treatment of uncomplicated falciparum malaria in the WHO Eastern Mediterranean Region. The threat of SP resistance remains as SP monotherapy is still common. Three day AS was superior to single-dose PQ for reducing gametocyte carriage. TRIAL REGISTRATION: ClinicalTrials.gov NCT00959517
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