258 research outputs found

    Simulation study on the effect of fuel-inlet angle on the swirling combustion

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    Swirling flameless combustion has been highly concerned nowadays due to ultra-low NOx and pollutant emission while delivering low temperature differential and stable combustion. Thanks to the rapid developed computational ability, simulation study has solved higher complexity of computational fluid dynamics problems for commercial and research aspect. In this project, the effect of swirling flameless combustion has been investigated by using computational method. In this study, a new setup has been modelled by varying fuel-inlet angle and to investigate the effect of swirling flameless combustion based on non-premixed swirling combustion furnace SFR 42 configuration. Non-premixed swirling combustion furnace SFR 42 is an asymmetric swirling combustion furnace that allows rapid mixing between air and fuel upstream of the reaction zone. The design of non-premixed swirling combustion furnace introduces visual characteristics of a premixed flame. This study shows that by changing the fuel-inlet angle to 45 degree tangentially, it will produce nine times lower NOX emission compared to fuel-inlet angle 5 degree tangentially. Fuel-inlet angle sloped 45 degree tangentially swirling combustion also produced peak temperature approximate 1400 K which has similar result compared to other cases. This condition helps to improve combustion efficiency and less pollutant emission. Temperature result of SFR 42 was taken as data validation of this project

    The risk models with non-local Poisson processes

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    The Poisson process is the most commonly used point process in modelling counting phenomena [21]. Even if the counting process has non-stationary increments, it can be shown to converge to the Poisson process if observed sufficiently long after a transient period as long as it constitutes a renewal process [43]. As such, it is important to review the key characteristics of the Poisson process as it serves as the main building block of more complex models. In the first part of this thesis, we propose two fractional risk models, where the classical risk process is time-changed by the mixture of tempered stable inverse subordinators. We characterise the risk processes by deriving the marginal distributions and establish the corresponding moments and covariance structure. In the second part of this thesis, we study the main characteristics of these models such as ruin probability and time of ruin, and illustrate the results with Monte Carlo simulations. The data suggests that the time of ruin can be approximated by the inverse gaussian distribution and its generalisations

    The effect of subgroup homogeneity of efficacy on contribution in public good dilemmas

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    open access articleThis paper examines how to maximize contribution in public good dilemmas by arranging people into homogeneous or heterogeneous subgroups. Past studies on the effect of homo- geneity of efficacy have exclusively manipulated group composition in their experimental designs, which might have imposed a limit on ecological validity because group membership may not be easily changed in reality. In this study, we maintained the same group composi- tion but varied the subgroup composition. We developed a public good dilemmas paradigm in which participants were assigned to one of the four conditions (high- vs. low-efficacy; homogeneous vs. heterogeneous subgroup) to produce their endowments and then to decide how much to contribute. We found that individuals in homogeneous and heteroge- neous subgroups produced a similar amount and proportion of contribution, which was due to the two mediating effects that counteracted each other, namely (a) perceived efficacy rel- ative to subgroup and (b) expectation of contribution of other subgroup members. This paper demonstrates both the pros and cons of arranging people into homogeneous and het- erogeneous subgroups of efficacy

    Baicalein antagonizes rotenone-induced apoptosis in dopaminergic SH-SY5Y cells related to Parkinsonism

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    <p>Abstract</p> <p>Background</p> <p>Two active compounds, baicalein and its glycoside baicalin were found in the dried root of <it>Scutellaria baicalensis </it>Georgi, and reported to be neuroprotective <it>in vitro </it>and <it>in vivo</it>. This study aims to evaluate the protective effects of baicalein on the rotenone-induced apoptosis in dopaminergic SH-SY5Y cells related to parkinsonism.</p> <p>Methods</p> <p>Cell viability and cytotoxicity were determined by MTT assay. The degree of nuclear apoptosis was evaluated with a fluorescent DNA-binding probe Hoechst 33258. The production of reactive oxidative species (ROS) and loss of mitochondrial membrane potential (ΔΨm) were determined by fluorescent staining with DCFH-DA and Rhodanmine 123, respectively. The expression of Bax, Bcl-2, cleaved caspase-3 and phosphorylated ERK1/2 was determined by the Western blots.</p> <p>Results</p> <p>Baicalein significantly increased viability and decreased rotenone-induced death of SH-SY5Y cells in a dose-dependent manner. Pre- and subsequent co-treatment with baicalein preserved the cell morphology and attenuated the nuclear apoptotic characteristics triggered by rotenone. Baicalein antagonized rotenone-induced overproduction of ROS, loss of ΔΨm, the increased expression of Bax, cleaved caspase-3 and phosphorylated ERK1/2 and the decreased expression of Bcl-2.</p> <p>Conclusion</p> <p>The antioxidative effect, mitochondrial protection and modulation of anti-and pro-apoptotic proteins are related to the neuroprotective effects of baicalein against rotenone induced cell death in SH-SY5Y cells.</p

    Early clearance of Chikungunya virus in children is associated with a strong innate immune response

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    Chikungunya fever (CHIKF) is a global infectious disease which can affect a wide range of age groups. The pathological and immunological response upon Chikungunya virus (CHIKV) infection have been reported over the last few years. However, the clinical profile and immune response upon CHIKV infection in children remain largely unknown. In this study, we analyzed the clinical and immunological response, focusing on the cytokine/chemokine profile in a CHIKV-infected pediatric cohort from Sarawak, Malaysia. Unique immune mediators triggered upon CHIKV infection were identified through meta-analysis of the immune signatures between this pediatric group and cohorts from previous outbreaks. The data generated from this study revealed that a broad spectrum of cytokines/chemokines is up-regulated in a sub-group of virus-infected children stratified according to their viremic status during hospitalization. Furthermore, different immune mediator profiles (the levels of pro-inflammatory cytokines, chemokines and growth and other factors) were observed between children and adults. This study gives an important insight to understand the immune response of CHIKV infection in children and would aid in the development of better prognostics and clinical management for children

    Return to work, work productivity loss and activity impairment in Chinese breast cancer survivors 12-month post-surgery: a longitudinal study

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    IntroductionExisting evidence of returning-to-work (RTW) after cancer comes predominately from Western settings, with none prospectively examined since the initial diagnostic phase. This study prospectively documents RTW-rate, time-to-RTW, work productivity loss, and activity impairment, within the first-year post-surgery among Chinese women with breast cancer (BCW) and identify potential causal co-variants.MethodsThis observational longitudinal study followed 371 Chinese BCW who were employed/self-employed at the time of diagnosis at 4-week post-surgery (baseline). RTW-status and time-to-RTW were assessed at baseline (T1), 4-month (T2), 6-month (T3), and 12-month (T4) post-baseline. WPAI work productivity loss and activity impairment were assessed at T4. Baseline covariates included demographics, medical-related factors, work satisfaction, perceived work demand, work condition, RTW self-efficacy, B-IPQ illness perception, COST financial well-being, EORTC QLQ-C30 and QLQ-BR23 physical and psychosocial functioning, and HADS psychological distress.ResultsA 68.2% RTW-rate (at 12-month post-surgery), prolonged delay in RTW (median = 183 days), and significant proportions of T4 work productivity loss (20%), and activity impairment (26%), were seen. BCW who were blue-collar workers with lower household income, poorer financial well-being, lower RTW self-efficacy, poorer job satisfaction, poorer illness perception, greater physical symptom distress, impaired physical functioning, and unfavorable work conditions were more likely to experience undesired work-related outcomes.DiscussionUsing a multifactorial approach, effective RTW interventions should focus on not only symptom management, but also to address psychosocial and work-environmental concerns. An organizational or policy level intervention involving a multidisciplinary team comprising nurses, psychologists, occupational health professionals, and relevant stakeholders in the workplace might be helpful in developing a tailored organizational policy promoting work-related outcomes in BCW

    A 21-Year-Old Pregnant Woman with Hypertension and Proteinuria

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    Ronald Ma and colleagues describe the differential diagnosis, investigation, and management of a 21-year-old pregnant woman presenting with hypertension and proteinuria at 20 weeks of gestation
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