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
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- Ë
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
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
(R.M. Lamuela-Raventos). + MODEL Please cite this article in press as: Medina-RemĂłn 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 Ă1.9 mm Hg [95% confidence interval (CI): Ă3.4; Ă0.6] and Ă2.6 mm Hg (CI: Ă4.2; Ă1.0), respectively, and reduced diastolic BP of Ă1.5 mm Hg (CI: Ă2.3; Ă0.6) and Ă1.9 mm Hg (CI: Ă2.8; Ă1.1). 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.
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Dietary αâLinolenic Acid, Marine Ïâ3 Fatty Acids, and Mortality in a Population With High Fish Consumption: Findings From the PREvenciĂłn con DIeta MEDiterrĂĄnea (PREDIMED) Study
Background: Epidemiological evidence suggests a cardioprotective role of αâlinolenic acid (ALA), a plantâderived Ïâ3 fatty acid. It is unclear whether ALA is beneficial in a background of high marine Ïâ3 fatty acids (longâchain nâ3 polyunsaturated fatty acids) intake. In persons at high cardiovascular risk from Spain, a country in which fish consumption is customarily high, we investigated whether meeting the International Society for the Study of Fatty Acids and Lipids recommendation for dietary ALA (0.7% of total energy) at baseline was related to allâcause and cardiovascular disease mortality. We also examined the effect of meeting the society's recommendation for longâchain nâ3 polyunsaturated fatty acids (â„500 mg/day). Methods and Results: We longitudinally evaluated 7202 participants in the PREvenciĂłn con DIeta MEDiterrĂĄnea (PREDIMED) trial. Multivariableâadjusted Cox regression models were fitted to estimate hazard ratios. ALA intake correlated to walnut consumption (r=0.94). During a 5.9ây followâup, 431 deaths occurred (104 cardiovascular disease, 55 coronary heart disease, 32 sudden cardiac death, 25 stroke). The hazard ratios for meeting ALA recommendation (n=1615, 22.4%) were 0.72 (95% CI 0.56â0.92) for allâcause mortality and 0.95 (95% CI 0.58â1.57) for fatal cardiovascular disease. The hazard ratios for meeting the recommendation for longâchain nâ3 polyunsaturated fatty acids (n=5452, 75.7%) were 0.84 (95% CI 0.67â1.05) for allâcause mortality, 0.61 (95% CI 0.39â0.96) for fatal cardiovascular disease, 0.54 (95% CI 0.29â0.99) for fatal coronary heart disease, and 0.49 (95% CI 0.22â1.01) for sudden cardiac death. The highest reduction in allâcause mortality occurred in participants meeting both recommendations (hazard ratio 0.63 [95% CI 0.45â0.87]). Conclusions: In participants without prior cardiovascular disease and high fish consumption, dietary ALA, supplied mainly by walnuts and olive oil, relates inversely to allâcause mortality, whereas protection from cardiac mortality is limited to fishâderived longâchain nâ3 polyunsaturated fatty acids. Clinical Trial Registration URL: http://www.Controlled-trials.com/. Unique identifier: ISRCTN35739639
Middle cerebral artery blood velocity is reduced with hyperthermia during prolonged exercise in humans
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 (VÌO2,max) 70 ± 1 ml minâ1 kgâ1 (mean ±s.e.m.)) performed two exercise trials at 57 % of VÌO2,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 â15 min of exercise.Concomitant with the development of hyperthermia, MCA Vmean declined by 26 ± 3 % from 73 ± 4 cm sâ1 at the beginning of exercise to 54 ± 4 cm sâ1 at exhaustion (P < 0.001). In contrast, MCA Vmean remained unchanged at 70-72 cm sâ1 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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