51 research outputs found

    Influence of the AlN interlayer thickness on the photovoltaic properties of in-rich AlInN on Si heterojunctions deposited by RF sputtering

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    8 pags., 5 figs., 1 tab.We report the influence of the AlN interlayer thickness (0-15 nm) on the photovoltaic properties of AlInN on Si heterojunction solar cells deposited by radio frequency sputtering. The poor junction band alignment and the presence of a 2-3 nm thick amorphous layer at the interface mitigates the response in devices fabricated by direct deposition of n-AlInN on p-Si(111). Adding a 4-nm-thick AlN buffer layer improves the AlInN crystalline quality and the interface alignment leading to devices with a conversion efficiency of 1.5% under 1-sun AM1.5G illumination. For thicker buffers the performance lessens due to inefficient tunnel transport through the AlN. These results demonstrate the feasibility of using In-rich AlInN alloys deposited by radio frequency sputtering as novel electron-selective contacts to Si-heterojunction solar cells.Support from projects NitPho (TEC2014-60483-R), ANOMALOS (TEC2015- 71127-C2-2-R), INFRASIL (TEC 2013-41730-R), SINFOTON (S2013/MIT 2790), MADRID-PV (2013/MAE-2780), PhotoAl (CCG2015/EXP-014), PAI research group (TEP-946 INNANOMAT), and FEDER-EU is acknowledged. TEM data were taken at DME-SC-ICyT-UCA. A. Nuñez- ˜ Cascajero thanks her grant to the University of Alcala and D. Montero acknowledges his contract ÂŽ BES-2014-067585

    Influence of the AlN interlayer thickness on the photovoltaic properties of In-rich AlInN on Si heterojunctions deposited by RF sputtering

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    We report the influence of the AlN interlayer thickness (0-15 nm) on the photovoltaic properties of Al0.37In0.63N on Si heterojunction solar cells deposited by radio frequency sputtering. The poor junction band alignment and the presence of a 2-3 nm thick amorphous layer at the interface mitigates the response in devices fabricated by direct deposition of n-AlInN on p-Si(111). Adding a 4-nm-thick AlN buffer layer improves the AlInN crystalline quality and the interface alignment leading to devices with a conversion efficiency of 1.5% under 1-sun AM1.5G illumination. For thicker buffers the performance lessens due to inefficient tunnel transport through the AlN. These results demonstrate the feasibility of using In-rich AlInN alloys deposited by radio frequency sputtering as novel electron-selective contacts to Si-heterojunction solar cells

    Gazpacho consumption is associated with lower blood pressure and reduced hypertension in a high cardiovascular risk cohort. Cross-sectional study of the PREDIMED trial

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    (R.M. Lamuela-Raventos). + MODEL Please cite this article in press as: Medina-Remón A, et al., Gazpacho consumption is associated with lower blood pressure and reduced hypertension in a high cardiovascular risk cohort. Abstract Background and aim: Hypertension is a major public health problem and a leading cause of death and disability in both developed and developing countries, affecting onequarter of the world's adult population. Our aim was to evaluate whether the consumption of gazpacho, a Mediterranean vegetable-based cold soup rich in phytochemicals, is associated with lower blood pressure (BP) and/or reduced prevalence of hypertension in individuals at high cardiovascular risk. Methods and results: We selected 3995 individuals (58% women, mean age 67 y) at high cardiovascular risk (81% hypertensive) recruited into the PREDIMED study. BP, weight, and dietary and physical activity data were collected. In multivariate linear regression analyses, after adjustment, moderate and high gazpacho consumption categories were associated with reduced mean systolic BP of À1.9 mm Hg [95% confidence interval (CI): À3.4; À0.6] and À2.6 mm Hg (CI: À4.2; À1.0), respectively, and reduced diastolic BP of À1.5 mm Hg (CI: À2.3; À0.6) and À1.9 mm Hg (CI: À2.8; À1.1). By multiple-adjusted logistic regression analysis, gazpacho consumption was associated with a lower prevalence of hypertension, with OR Z 0.85 (CI: 0.73; 0.99) for each 250 g/week increase and OR Z 0.73 (CI: 0.55; 0.98) for high gazpacho consumption groups compared to the no-consumption group. Conclusions: Gazpacho consumption was inversely associated with systolic and diastolic BP and prevalence of hypertension in a cross-sectional Mediterranean population at high cardiovascular risk. The association between gazpacho intake and reduction of BP is probably due to synergy among several bioactive compounds present in the vegetable ingredients used to make the recipe.

    Multiple sclerosis coinciding with Machado-Joseph disease

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    Middle cerebral artery blood velocity is reduced with hyperthermia during prolonged exercise in humans

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    In the present study we examined the effect of hyperthermia on the middle cerebral artery mean blood velocity (MCA Vmean) during prolonged exercise. We predicted that the cerebral circulation would be impaired when hyperthermia is present during exercise and assumed that this could be observed as a reduced MCA Vmean.Eight endurance trained men (maximum oxygen uptake (V̇O2,max) 70 ± 1 ml min−1 kg−1 (mean ±s.e.m.)) performed two exercise trials at 57 % of V̇O2,max on a cycle ergometer in a hot (40 °C; hyperthermic trial) and in a thermoneutral environment (18 °C; control trial). In the hyperthermic trial, the oesophageal temperature increased throughout the exercise period reaching a peak value of 40.0 ± 0.1 °C at exhaustion after 53 ± 4 min of exercise. In the control trial, exercise was maintained for 1 h without any signs of fatigue and with core temperature stabilised at 37.8 ± 0.1 °C after ≈15 min of exercise.Concomitant with the development of hyperthermia, MCA Vmean declined by 26 ± 3 % from 73 ± 4 cm s−1 at the beginning of exercise to 54 ± 4 cm s−1 at exhaustion (P < 0.001). In contrast, MCA Vmean remained unchanged at 70-72 cm s−1 throughout the 1 h control trial.When individually determined regression lines for MCA Vmean and arterial carbon dioxide pressure (Pa,CO2) obtained during preliminary exercise tests were used to account for the differences in Pa,CO2 between the hyperthermic and control trial, it appeared that more than half of the reduction in MCA Vmean (56 ± 8 %) was related to a hyperventilation-induced drop in Pa,CO2. Declining cardiac output and arterial blood pressure accounted for the remaining part of the hyperthermia-induced reduction in MCA Vmean.The present results demonstrate that the development of hyperthermia during prolonged exercise is associated with a marked reduction in MCA Vmean
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