3,289 research outputs found

    Experimental and CFD analysis of the wake characteristics of tidal turbines

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    This is the author accepted manuscript. The final version is available from the publisher via the DOI in this record.This paper investigates the accuracy of the Computational Fluid Dynamics (CFD) based Immersed Body Force (IBF) turbine modelling method for predicting the flow characteristics of a Momentum-Reversal-Lift type of tidal turbine. This empirically-based CFD model has been developed based on the actuator disc method enhanced with additional features to mimic the effect of the complex blade motion on the downstream wake, without the high computational costs of explicitly modelling the dynamic blade motion. The model has been calibrated against the flow characteristics data obtained from experiment and found to perform well, although there are few inconsistencies in the flow patterns which show some of the limitations of the IBF model compared to a full dynamic blade motion simulation. However, given the complexity and computational cost of modelling the detailed blade motion the limitations of the IBF model are acceptable and will be useful especially for optimisation of arrays of devices where there is a significant computational demand.We would like to thank EPSRC for providing the funding under project number EP/J010138/1, as part of the Supergen Marine research program and the IFREMER personnel of Boulogne-sur-Mer for their assistance and advice during the experimental trials

    Bucillamine prevents cisplatin-induced ototoxicity through induction of glutathione and antioxidant genes.

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    Bucillamine is used for the treatment of rheumatoid arthritis. This study investigated the protective effects of bucillamine against cisplatin-induced damage in auditory cells, the organ of Corti from postnatal rats (P2) and adult Balb/C mice. Cisplatin increases the catalytic activity of caspase-3 and caspase-8 proteases and the production of free radicals, which were significantly suppressed by pretreatment with bucillamine. Bucillamine induces the intranuclear translocation of Nrf2 and thereby increases the expression of γ-glutamylcysteine synthetase (γ-GCS) and glutathione synthetase (GSS), which further induces intracellular antioxidant glutathione (GSH), heme oxygenase 1 (HO-1) and superoxide dismutase 2 (SOD2). However, knockdown studies of HO-1 and SOD2 suggest that the protective effect of bucillamine against cisplatin is independent of the enzymatic activity of HO-1 and SOD. Furthermore, pretreatment with bucillamine protects sensory hair cells on organ of Corti explants from cisplatin-induced cytotoxicity concomitantly with inhibition of caspase-3 activation. The auditory-brainstem-evoked response of cisplatin-injected mice shows marked increases in hearing threshold shifts, which was markedly suppressed by pretreatment with bucillamine in vivo. Taken together, bucillamine protects sensory hair cells from cisplatin through a scavenging effect on itself, as well as the induction of intracellular GSH

    Charge-spin correlation in van der Waals antiferromagenet NiPS3

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    Strong charge-spin coupling is found in a layered transition-metal trichalcogenide NiPS3, a van derWaals antiferromagnet, from our study of the electronic structure using several experimental and theoretical tools: spectroscopic ellipsometry, x-ray absorption and photoemission spectroscopy, and density-functional calculations. NiPS3 displays an anomalous shift in the optical spectral weight at the magnetic ordering temperature, reflecting a strong coupling between the electronic and magnetic structures. X-ray absorption, photoemission and optical spectra support a self-doped ground state in NiPS3. Our work demonstrates that layered transition-metal trichalcogenide magnets are a useful candidate for the study of correlated-electron physics in two-dimensional magnetic material.Comment: 6 pages, 3 figur

    Unconventional spin-phonon coupling via the Dzyaloshinskii???Moriya interaction

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    Spin-phonon coupling (SPC) plays a critical role in numerous intriguing phenomena of transition metal oxides (TMOs). In 3d and 4d TMOs, the coupling between spin and lattice degrees of freedom is known to originate from the exchange interaction. On the other hand, the origin of SPC in 5d TMOs remains to be elucidated. To address this issue, we measured the phonon spectra of the 5d pyrochlore iridate Y 2 Ir 2 O 7 using optical spectroscopy. Three infrared-active phonons soften below the N??el temperature of T N ??? 170 K, indicating the existence of strong SPC. Simulations using density functional theory showed that the coupling is closely related to the Ir???O???Ir bond angle. A tight-binding model analysis reveals that this SPC is mainly mediated by the Dzyaloshinskii???Moriya interaction rather than the usual exchange interaction. We suggest that such unconventional SPC may be realized in other 5d TMOs with non-collinear magnetic order

    The Effects of DMPF on Honey Bee Pathophysiology

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    Varroa destructor is a parasitic mite that is the leading cause of honey bee colony loss in the United States. To mitigate these losses, beekeepers apply acaricide treatments. N-(2,4-dimethylphenyl) formamide (DMPF), the active metabolite in amitraz, was the highest detected pesticide in the 2017 US National Honey Bee Survey (NHBS), where samples of bees and wax were taken from 300 different apiaries across the United States. Although amitraz is relatively non-toxic to bees, very little is known about its effects on honey bee physiology, which has shown to be a useful tool in predicting overall colony health. This study investigates the potential effects of DMPF in adult honey bees across 19 pathophysiological traits. Samples of adult bees were necropsied from colonies with known levels of DMPF in the comb wax and compared to bees from colonies with no DMPF detections. The statistical results indicate potential associations between physiological symptoms in honey bee organs such as the ventriculus, Malpighian tubules, rectum, sting gland, and venom sac to varying DMPF concentrations. These findings serve to identify preliminary evidence for future work quantifying the overall effects of DMPF on colony health.vanEngelsdorp Bee La

    Maternal-Fetal Attachment and Maternal Identity according to Type of Stress Coping Strategies on Immigration Pregnancy Women

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    PURPOSE: The purpose of this descriptive survey study was designed to identify the stress coping types of married immigrant pregnant women and find out the differences in maternal-fetal attachment and maternal identity based on each types. METHODS: 151 married immigrant women who visited 3 women's hospitals located in J-do for pre-pregnancy checkup were selected as study objects. Data were analyzed by dsecriptive statistics, cluster analysis, t- test, ANOVA, and Scheffe multiple comparison test. RESULTS: Cluster analysis revealed 4 distinct stress coping styles; low stress-coping involvement social support-oriented type, high stress-coping involvement hopeful thinking type, low stress-coping involvement type, effective stress coping types. Women frequently using effective stress coping type among the four types reported higher maternal-fetal attachment. The group of active coping styles got significantly higher score on maternal identity. CONCLUSION: Proper stress coping of married immigrant pregnant women regarding pregnancies proved to result in high levels of maternal-fetal attachment and maternal identity. Studies measuring the stress coping styles that affect pregnancies should be continuously conducted
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