71 research outputs found

    Finite time thermodynamic analysis and optimization of solar-dish Stirling heat engine with regenerative losses

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    The present study investigates the performance of the solar-driven Stirling engine system to maximize the power output and thermal efficiency using the non-linearized heat loss model of the solar dish collector and the irreversible cycle model of the Stirling engine. Finite time thermodynamic analysis has been done for combined system to calculate the finite-rate heat transfer, internal heat losses in the regenerator, conductive thermal bridging losses and finite regeneration process time. The results indicate that exergy efficiency of dish system increases as the effectiveness of regenerator increases but decreases with increase in regenerative time coefficient. It is also found that optimal range of collector temperature and corresponding concentrating ratio are 1000 K~1400 K and 1100~1400, respectively in order to get maximum value of exergy efficiency. It is reported that the exergy efficiency of this dish system can reach the maximum value when operating temperature and concentrating ratio are 1150 K and 1300, respectively

    Steady-state multiplicity and transient behaviour of a lumped-parameter solid oxide fuel cell

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    The existence of multiple steady-state solutions within a planar, zero-dimensional Solid Oxide Fuel Cell (SOFC) is investigated. The model presented here is a development of the SOFC model by Bavarian and Soroush (2012), where the heat-transfer coefficients are no longer assumed to be constant, and momentum conservation is considered within the gas channels. The steady-state behaviour of the SOFC is investigated for three modes of operation: (i) constant external load; (ii) constant voltage; (iii) constant current. For (i) and (ii), up to three steady-state solutions exists: two stable and one unstable. The main focus is on the first mode of operation, where the effect of the different inlet parameters on SOFC performance is also considered. The dynamic model is also considered for a Solid Oxide Fuel Cell operating under a constant external load. The different time-scales relevant to this model is investigated to highlight the multi-time-scale nature of the SOFC system. The transient behaviour of the SOFC is investigated for changes in value of the external load resistance Rload_{load}. Rload_{load} is expressed as a smooth function of time such that it changes smoothly from one value to another around 100 seconds. The evolution of different SOFC parameters with time is investigated, as well as the transient behaviour of the SOFC during ignition and extinction. The results show that at least two different operating regimes exist within a Solid Oxide Fuel Cell. The transient behaviour of the SOFC operating along the unstable steady-state branch is also covered

    Non-steroidal anti-inflammatory drugs for treating symptomatic uncomplicated urinary tract infections in non-pregnant adult women

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    This is a protocol for a Cochrane Review (intervention). The objectives are as follows: This review aims to investigate the benefits and risks associated with the use of NSAIDs in the treatment of symptomatic uncomplicated UTIs in non‐pregnant adult women

    Selective inhibition of miR-21 by phage display screened peptide

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    miRNAs are nodal regulators of gene expression and deregulation of miRNAs is causally associated with different diseases, including cancer. Modulation of miRNA expression is thus of therapeutic importance. Small molecules are currently being explored for their potential to downregulate miRNAs. Peptides have shown to have better potency and selectivity toward their targets but their potential in targeting and modulating miRNAs remain unexplored. Herein, using phage display we found a very selective peptide against pre-miR-21. Interestingly, the peptide has the potential to downregulate miR-21, by binding to pre-miR-21 and hindering Dicer processing. It is selective towards miR-21 inside the cell. By antagonising miR-21 function, the peptide is able to increase the expression of its target proteins and thereby increase apoptosis and suppress cell proliferation, invasion and migration. This peptide can further be explored for its anti-cancer activity in vivo and may be even extended to clinical studies

    Effect of integrated nutrient management on growth and yield of radish

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    Integrated Nutrient Management (INM) is necessary to enhance sustainable yield in an eco-friendly way. A field experiment was conducted in the research field of Midwest Academy and Research Institute College of Live Sciences, Tulsipur, Dang from November 2018 to January 2019 to investigate the effect of integrated nutrient management on growth and yield of radish. Mino Early variety was used in the experiment. The experiment was laid out on Randomized Complete Block Design with four replications and 5 treatments. Nitrogen (N) was supplied through different sources. The treatment combinations were: control (T1), 100% recommended N through chemical fertilizer (T2), 50% recommended N through chemical fertilizer + 50% N through farmyard manure (FYM) (T3), 50% recommended N through chemical fertilizer + 50% N through poultry manure (T4) and 50% recommended N through chemical fertilizer + 50% vermicompost (T5). Significant effect was noted on leaf numbers, root length, root diameter and yield per ha but no significant effect was noted on the germination percentage and plant height. The highest germination percentage  (77.00 %), plant height (13.27 cm), root length (16.94 cm), root diameter (3.01 cm), and yield per ha (16.55 t/ha) was recorded at T4 (50% recommended N through chemical fertilizer + 50% N through poultry manure). T5 (50% recommended N through chemical fertilizer + 50% vermicompost) recorded the highest leaf numbers (10.40). In our experiment, T4 (50% recommended N through chemical fertilizer + 50% N through poultry manure) was found to be superior, so in inner terai places like Tulsipur, Dang it is suggested to apply 50% recommended N through chemical fertilizer + 50% N through poultry manure to obtain a high yield of radish

    Time to Turn on the Blue Lights: A Systematic Review and Meta-analysis of Photodynamic Diagnosis for Bladder Cancer.

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    CONTEXT: White light (WL) cystoscopy and transurethral resection of bladder tumour (TURBT) comprise the current gold standard technique for detecting and grading bladder cancer. However, with WL cystoscopy, recurrence following initial TURBT is high, and identification of smaller tumours and carcinoma in situ is poor. Photodynamic diagnosis (PDD) has been developed to improve the detection of bladder. OBJECTIVE: To assess the effect of PDD-guided TURBT compared with WL on recurrence rates (RRs) in non-muscle-invasive bladder cancer (NMIBC). EVIDENCE ACQUISITION: A systematic review of the literature from inception to April 2020 using Medline, EMBASE, and CENTRAL was undertaken. Randomised control trials comparing TURBT undertaken with PDD to WL that reported RRs of at least 12 mo were included in the analysis. The primary outcomes were RRs at 12 and 24 mo. The secondary outcomes were reported adverse effects. The Grading of Recommendations Assessment, Development and Evaluation (GRADE) methodology was used to assess the certainty of the evidence. EVIDENCE SYNTHESIS: Twelve randomised controlled trials (2288 patients) were included for the meta-analysis. PDD was found to reduce RRs at 12 mo (RR 0.73, confidence interval [CI] 0.60-0.88) and 24 mo (RR 0.75, CI 0.62-0.91). There was an increased risk of recurrence for patients undergoing WL at 12 mo (hazard ratio [HR] 1.14, CI 1.05-1.23) and 24 mo (HR 1.25, CI 1.15-1.35). Two studies reported recurrence data at 60 mo showing statistically significant outcomes in favour of PDD: one showed lower RRs for PDD (49% PDD vs 68% WL), whilst the other showed increased recurrence-free survival (68.2% PDD vs 57.3% WL). Adverse effects appeared to be minimal, though poorly reported. A GRADE analysis showed the evidence to be of moderate certainty overall. CONCLUSIONS: This systematic review found that PDD reduced RRs and improved recurrence-free survival compared with WL in NMIBC over at least 2-yr follow-up. These effects may persist up to 5 yr. Further research in a pragmatic study looking at longer-term outcomes beyond 24 mo will help guide recommendations on clinical adoption. PATIENT SUMMARY: This review suggests that photodynamic diagnosis, compared with white light cystoscopy, improves recurrence-free survival in non-muscle-invasive bladder cancer over at least 2 yr of follow-up. However, confirmatory pragmatic studies with longer-term outcomes are required for its clinical adoption
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