117 research outputs found

    Free convection heat and mass transfer of a nanofluid past a horizontal cylinder embedded in a non-Darcy porous medium

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    In the present paper, we analyzed the laminar boundary layer ïŹ‚ow and heat transfer from a horizontal cylinder in a nanoïŹ‚uid-saturated non-Darcy porous medium in the presence of thermal radiation. This is the ïŹrst paper presenting non-similar solutions for such a regime.The boundary layer conservation equations,which are parabolic in nature,are normalized into non-similar form and then solved computationally with an efïŹcient, implicit, stable Keller-box ïŹnite difference scheme. Non-Darcy effects are simulated via a second-order Forchheimer drag force term in the momentum boundary layer equation. The model used for the nanoïŹ‚uid incorporates the effects of Brownian motion, buoyancy ratio, and thermophoresis. A non-similarity solution is presented that depends on the Brownian motion number (Nb), buoyancy ratio (Nr), thermophoresis number (Nt), Forchheimer parameter (Λ), and radiation parameter (F). Velocity is reduced with increasing Forchheimer parameter, whereas temperature and nanoparticle concentration are both enhanced.The model ïŹnds applications in energy systems and thermal enhancement of industrial ïŹ‚ow processe

    The use of quantitative sensory testing in cancer pain assessment: A systematic review

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    Objective: To summarize the literature on the use of quantitative sensory testing (QST) in the assessment of pain in people with cancer and to describe which QST parameters consistently demonstrate abnormal sensory processing in patients with cancer pain. Databases and Data Treatment: Medline, EMBASE, AMED, CINAHL, SCOPUS and CENTRAL were searched for observational or experimental studies using QST in patients with a cancer diagnosis and reporting pain. Search strategies were based on the terms “quantitative sensory testing”, “cancer”, “pain”, “cancer pain” and “assessment”. Databases were searched from inception to January 2019. Data were extracted and synthesized narratively, structured around the different QST modalities and sub‐grouped by cancer pain aetiology (tumour‐ or treatment‐related pain). Results: Searches identified 286 records of which 18 met the eligibility criteria for inclusion. Three studies included patients with tumour‐related pain, and 15 studies included patients with pain from chemotherapy‐induced peripheral neuropathy (CIPN). Across all studies, 50% (9/18) reported sensory abnormities using thermal detection thresholds (cool and warm), 44% (8/18) reported abnormal mechanical detection thresholds using von‐Frey filaments and 39% (7/18) found abnormal pinprick thresholds. Abnormal vibration and thermal pain (heat/cold) thresholds were each reported in a third of included studies. Conclusion: This systematic review highlights the lack of published data characterizing the sensory phenotype of tumour‐related cancer pain. This has implications for our understanding of the underlying pathophysiological mechanisms of cancer pain. Understanding the multiple mechanisms driving cancer pain will help to move towards rational individualized analgesic treatment choices. Significance: This systematic review found that pain in cancer patients is associated with abnormal sensory responses to thermal, mechanical and pinprick stimuli. However, these findings are based primarily on studies of chemotherapy‐induced peripheral neuropathy and data on tumour‐related pain are lacking, warranting further research

    Brain immune cells undergo cGAS-STING-dependent apoptosis during herpes simplex virus type 1 infection

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    Protection of the brain from viral infections involves the type I interferon (IFN-I) system, defects in which renders humans susceptible to herpes simplex encephalitis (HSE). However, excessive cerebral IFN-I levels leads to pathologies, suggesting the need for tight regulation of responses. Based on data from mouse models, human HSE cases, and primary cell culture systems, we here show that microglia and other immune cells undergo apoptosis in the HSV-1-infected brain through a mechanism dependent on the cyclic GMP-AMP synthase (cGAS) - stimulator of interferon genes (STING) pathway, but independent of IFN-I. HSV-1 infection of microglia induced cGAS-dependent apoptosis at high viral doses, while lower viral doses led to IFN-I responses. Importantly, inhibition of caspase activity prevented microglial cell death and augmented IFN-I responses. Accordingly, HSV-1-infected organotypic brain slices, or mice treated with caspase inhibitor, exhibited lower viral load and improved outcome of infection. Collectively, we identify an activation-induced apoptosis program in brain immune cells which down-modulates local immune responses

    Smart homes and their users:a systematic analysis and key challenges

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    Published research on smart homes and their users is growing exponentially, yet a clear understanding of who these users are and how they might use smart home technologies is missing from a field being overwhelmingly pushed by technology developers. Through a systematic analysis of peer-reviewed literature on smart homes and their users, this paper takes stock of the dominant research themes and the linkages and disconnects between them. Key findings within each of nine themes are analysed, grouped into three: (1) views of the smart home-functional, instrumental, socio-technical; (2) users and the use of the smart home-prospective users, interactions and decisions, using technologies in the home; and (3) challenges for realising the smart home-hardware and software, design, domestication. These themes are integrated into an organising framework for future research that identifies the presence or absence of cross-cutting relationships between different understandings of smart homes and their users. The usefulness of the organising framework is illustrated in relation to two major concerns-privacy and control-that have been narrowly interpreted to date, precluding deeper insights and potential solutions. Future research on smart homes and their users can benefit by exploring and developing cross-cutting relationships between the research themes identified

    Use of multi-trait and random regression models to identify genetic variation in tolerance to porcine reproductive and respiratory syndrome virus

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    Background: A host can adopt two response strategies to infection: resistance (reduce pathogen load) and tolerance (minimize impact of infection on performance). Both strategies may be under genetic control and could thus be targeted for genetic improvement. Although there is evidence that supports a genetic basis for resistance to porcine reproductive and respiratory syndrome (PRRS), it is not known whether pigs also differ genetically in tolerance. We determined to what extent pigs that have been shown to vary genetically in resistance to PRRS also exhibit genetic variation in tolerance. Multi-trait linear mixed models and random regression sire models were fitted to PRRS Host Genetics Consortium data from 1320 weaned pigs (offspring of 54 sires) that were experimentally infected with a virulent strain of PRRS virus to obtain genetic parameter estimates for resistance and tolerance. Resistance was defined as the inverse of within-host viral load (VL) from 0 to 21 (VL21) or 0 to 42 (VL42) days post-infection and tolerance as the slope of the reaction-norm of average daily gain (ADG21, ADG42) on VL21 or VL42. Results: Multi-trait analysis of ADG associated with either low or high VL was not indicative of genetic variation in tolerance. Similarly, random regression models for ADG21 and ADG42 with a tolerance slope fitted for each sire did not result in a better fit to the data than a model without genetic variation in tolerance. However, the distribution of data around average VL suggested possible confounding between level and slope estimates of the regression lines. Augmenting the data with simulated growth rates of non-infected half-sibs (ADG0) helped resolve this statistical confounding and indicated that genetic variation in tolerance to PRRS may exist if genetic correlations between ADG0 and ADG21 or ADG42 are low to moderate. Conclusions: Evidence for genetic variation in tolerance of pigs to PRRS was weak when based on data from infected piglets only. However, simulations indicated that genetic variance in tolerance may exist and could be detected if comparable data on uninfected relatives were available. In conclusion, of the two defense strategies, genetics of tolerance is more difficult to elucidate than genetics of resistance.</p

    Radiative and magnetohydrodynamics flow of third grade viscoelastic fluid past an isothermal inverted cone in the presence of heat generation/absorption

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    A mathematical analysis is presented to investigate the nonlinear, isothermal, steady-state, free convection boundary layer flow of an incompressible third grade viscoelastic fluid past an isothermal inverted cone in the presence of magnetohydrodynamic, thermal radiation and heat generation/absorption. The transformed conservation equations for linear momentum, heat and mass are solved numerically subject to the realistic boundary conditions using the second-order accurate implicit finite-difference Keller Box Method. The numerical code is validated with previous studies. Detailed interpretation of the computations is included. The present simulations are of interest in chemical engineering systems and solvent and low-density polymer materials processing

    Path and Ridge Regression Analysis of Seed Yield and Seed Yield Components of Russian Wildrye (Psathyrostachys juncea Nevski) under Field Conditions

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    The correlations among seed yield components, and their direct and indirect effects on the seed yield (Z) of Russina wildrye (Psathyrostachys juncea Nevski) were investigated. The seed yield components: fertile tillers m-2 (Y1), spikelets per fertile tillers (Y2), florets per spikelet- (Y3), seed numbers per spikelet (Y4) and seed weight (Y5) were counted and the Z were determined in field experiments from 2003 to 2006 via big sample size. Y1 was the most important seed yield component describing the Z and Y2 was the least. The total direct effects of the Y1, Y3 and Y5 to the Z were positive while Y4 and Y2 were weakly negative. The total effects (directs plus indirects) of the components were positively contributed to the Z by path analyses. The seed yield components Y1, Y2, Y4 and Y5 were significantly (P<0.001) correlated with the Z for 4 years totally, while in the individual years, Y2 were not significant correlated with Y3, Y4 and Y5 by Peason correlation analyses in the five components in the plant seed production. Therefore, selection for high seed yield through direct selection for large Y1, Y2 and Y3 would be effective for breeding programs in grasses. Furthermore, it is the most important that, via ridge regression, a steady algorithm model between Z and the five yield components was founded, which can be closely estimated the seed yield via the components
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