163 research outputs found

    Noise and vibration from building-mounted micro wind turbines Part 2: Results of measurements and analysis

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    Description To research the quantification of vibration from a micro turbine, and to develop a method of prediction of vibration and structure borne noise in a wide variety of installations in the UK. Objective The objectives of the study are as follows: 1) Develop a methodology to quantify the amount of source vibration from a building mounted micro wind turbine installation, and to predict the level of vibration and structure-borne noise impact within such buildings in the UK. 2) Test and validate the hypothesis on a statically robust sample size 3) Report the developed methodology in a form suitable for widespread adoption by industry and regulators, and report back on the suitability of the method on which to base policy decisions for a future inclusion for building mounted turbines in the GPDO

    Direct inhibition of the pacemaker (I-f) current in rabbit sinoatrial node cells by genistein

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    1 Genistein is a tyrosine kinase inhibitor which interferes with the activity of several ionic channels either by altering modulatory phosphorylating processes or by direct binding. In whole-cell conditions, genistein induces a partial inhibition of the pacemaker (If) current recorded in cardiac sinoatrial and ventricular myocytes. 2 We investigated the mechanism of action of genistein (50 mM) on the If current in whole-cell, cellattached, and inside-out configurations, and the measured fractional inhibitions were similar: 26.6, 27.2, and 33.6%, respectively. 3 When ATP was removed from the whole-cell pipette solution no differences were revealed in the effect of the drug when compared to metabolically active cells. Genistein fully maintained its blocking ability even when herbimycin, a tyrosine kinase inhibitor, was added to the whole-cell ATP-free pipette solution. 4 Genistein-induced block was independent of the gating state of the channel and did not display voltage or current dependence; this independence distinguishes genistein from all other f-channel blockers. 5 When inside-out experiments were performed to test for a direct interaction with the channel, genistein, superfused on the intracellular side of the membrane, decreased the maximal If conductance, and slightly shifted the current\u2013activation curve to the left. Furthermore, the effect of genistein was independent of cAMP modulation. 6 We conclude that, in addition to its tyrosine kinase-inhibitory properties, genistein also blocks If by directly interacting with the channel, and thus cannot be considered a valuable pharmacological tool to investigate phosphorylation-dependent modulatory pathways of the If current and of cardiac rhythm

    Noise and vibration from building-mounted micro wind turbines part 3 : prediction methodology

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    This brief report describes a simplified method for estimation of levels of structure-borne sound in buildings to which a micro-wind turbine (MWT) is attached. The method is applicable to two specific designs of MWT, each for three lengths of mounting pole and for masonry buildings. The output gives expected noise level for given rotational speed of the MWT. Applicability and limitations of the method are described. A more general methodology is provided in companion reports but requires specialist knowledge to implement. Structure-borne sound is notoriously difficult to predict and several assumptions have been necessary in order to produce a sufficiently simple estimation method. Therefore, caution is required in relying on the predictions until sufficient confidence has been built up through experience of real installations

    Prevention of Heart Failure in Rats by Trimetazidine Treatment: A Consequence of Accelerated Phospholipid Turnover?

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    ABSTRACT Heart failure is known for alteration of cardiac catecholamine responsiveness involving adrenergic receptor (AR) down-regulation. Trimetazidine, a metabolically active anti-ischemic drug, accelerates the turnover of phospholipids. The present study evaluated the consequences of trimetazidine treatment (supposed to increase phospholipid synthesis) on AR in heart failure in rats. In control rats, trimetazidine (7.5 mg/day supplied in the diet) induced after 8 weeks a significant increase in both ␤-(ϩ54%) and ␣-AR (ϩ30%) density, although after 12 weeks, the receptor density was normalized. Heart failure was obtained by ascending aortic banding. These heart failure rats developed a severe cardiac hypertrophy, mainly affecting the left ventricle, which was significantly reduced in the trimetazidine-treated group. The plasma level of brain natriuretic peptide (BNP), a marker of heart failure severity, was significantly increased in the heart failure group as compared with the sham group (900 and 1200% after 8 and 12 weeks, respectively). In the trimetazidine-treated group, the plasma BNP increase was significantly lower. The development of heart failure was associated with a decrease in ␤-and ␣-AR sites (Ϫ23 and Ϫ36% versus sham, respectively) after 8 weeks and continued to decrease after 12 weeks (Ϫ37 and Ϫ48% versus sham, respectively). This down-regulation was prevented by trimetazidine without alteration in affinity. These results suggest that trimetazidine prevents AR desensitization and cardiac hypertrophy, in a pressure-overload model of heart failure. This cytoprotection suggests that membrane homeostasis preservation may be considered as a therapeutic target in the treatment of heart failure

    Migration control: A distance compensation strategy in ants

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    ©The Author(s) 2016. This article is published with open access at Springerlink.com. Migratory behaviour forms an intrinsic part of the life histories of many organisms but is often a high-risk process. Consequently, varied strategies have evolved to negate such risks, but empirical data relating to their functioning are limited. In this study, we use the model system of the househunting ant Temnothorax albipennis to demonstrate a key strategy that can shorten migration exposure times in a group of social insects. Colonies of these ants frequently migrate to new nest sites, and due to the nature of their habitat, the distances over which they do so are variable, leading to fluctuating potential costs dependent on migration parameters. We show that colonies of this species facultatively alter the dynamics of a migration and so compensate for the distance over which a given migration occurs. Specifically, they achieve this by modulating the rate of ‘tandem running’, in which workers teach each other the route to a new nest site. Using this method, colonies are able to engage a larger number of individuals in the migration process when the distance to be traversed is greater, and furthermore, the system appears to be based on perceived encounter rate at the individual level. This form of decentralised control highlights the adaptive nature of a behaviour of ecological importance, and indicates that the key to its robustness lies in the use of simple rules. Additionally, our results suggest that such coordinated group reactions are central to achieving the high levels of ecological success seen in many eusocial organisms

    Role of C677T and A1298C MTHFR, A2756G MTR and -786 C/T eNOS Gene Polymorphisms in Atrial Fibrillation Susceptibility

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    Hyperhomocysteinemia has been suggested to play a role in the NonValvular Atrial Fibrillation (NVAF) pathogenesis. Polymorphisms in genes coding for homocysteine (Hcy) metabolism enzymes may be associated with hyperhomocysteinemia and NVAF.456 NVAF patients and 912 matched controls were genotyped by an electronic microchip technology for C677T and A1298C MTHFR, A2756G MTR, and -786C/T eNOS gene polymorphisms. Hcy was determined by an immunoassay method.The genotype distribution of the four polymorphisms as well as genotype combinations did not differ in patients and controls. Hcy was higher in patients than in controls (15.2, 95%CI 14.7–15.7 vs 11.3, 95%CI 11.0–11.6 µmol/L; p<0.0001). In both populations, a genotype-phenotype association (p<0.0001) between Hcy and C677T MTHFR polymorphism was observed; in controls a significant (p = 0.029) association between tHcy and −786C/T eNOS polymorphism was also observed. At the multivariate analysis the NVAF risk significantly increased in the upper quartiles of Hcy compared to the lowest: OR from 2.8 (1.68–4.54 95%CI) in Q2 to 12.9 (7.96–21.06 95%CI) in Q4. or in combination
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