123,721 research outputs found
L’exemple de la Belgique
No full textOzer André. L’exemple de la Belgique. In: Géographes associés n°27,2003. Quelle géographie enseigner demain à l'Université ? Géoforum de Liège 23 et 25 mai 2003. pp. 131-132
A. Ozer et A. Ulzega, Livret-guide de l'excursion-table ronde sur le Tyrrhénien de Sardaigne
No full textSanlaville Paul, Paskoff Roland. A. Ozer et A. Ulzega, Livret-guide de l'excursion-table ronde sur le Tyrrhénien de Sardaigne. In: Annales de Géographie, t. 90, n°502, 1981. pp. 744-747
Analysis and Simulation of Superlattice GaN/InGaN p-i-n Solar Cells
No full textIndium gallium nitride (InGaN) is becoming a promising semiconductor
material for fabrication of solar cells due to its high absorption coefficient (about
105 cm-1) and tunable (by its In content) direct band-gap, from 0.71 eV (EInN) to
3.43 eV (EGaN). Solar cells based on structures with variable In content should
show a reduction of thermalization losses, absorbing almost the whole of solar
spectrum. Unfortunately, these advantages are partially lost and InGaN solar cells
performance reduced due to technological issues (low quality of InGaN layer
growth on GaN substrate) and wurtzite nature of InGaN semiconductor (spontaneous
and piezoelectric polarizations), in particular in case of In-rich ternary alloy.
This paper is focused on the parametric analysis and simulation of an intermediate
band (IB) superlattice GaN/InGaN p-i-n solar cell on GaN quasi-bulk substrate.
Photovoltaic device performances are investigated and simulated as a function of
both In concentration in GaN/InGaN quantum wells (QWs) and QW number. For a superlattice with 28 QWs, an efficiency of 1.05 % with a short-circuit current
density of 1.193 mA/cm2 has been achieved. Furthermore, some considerations on
the possibility to obtain a more efficient InGaN solar cell with a wider absorption
spectrum using InN quantum dots (QDs) in a photovoltaic device structure are also
derived
A. Ozer et A. Ulzega, Livret-guide de l'excursion-table ronde sur le Tyrrhénien de Sardaigne
No full textSanlaville Paul, Paskoff Roland. A. Ozer et A. Ulzega, Livret-guide de l'excursion-table ronde sur le Tyrrhénien de Sardaigne. In: Annales de Géographie, t. 90, n°502, 1981. pp. 744-747
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Vitamin E inhibits CD36 scavenger receptor expression in hypercholesterolemic rabbits
No full textA numerous studies suggest that Vitamin E has a preventive role in atherosclerosis, although the mechanism of action still remains unclear. CD36, a member of the scavenger receptor family is centrally involved in the uptake of oxidized low density proteins (oxLDLs) from bloodstream. During the atherosclerotic process, the lipid cargo of oxLDL accumulates in macrophages and smooth muscle cells, inducing their pathological conversion to foam cells. In the present study, we investigate the role of Vitamin E on CD36 expression in an in vivo model. Atherosclerosis was induced by a 2% cholesterol containing Vitamin E poor diet. Three groups of six rabbits each were studied. The first group (control) was fed on Vitamin E poor diet. The second group was fed with Vitamin E poor diet containing 2% cholesterol and the rabbits in the third group were fed with Vitamin E poor diet containing 2% cholesterol and received injections of 50 mg/kg of Vitamin E i.m. After 4 weeks, aortas were removed and analysed by light microscopy for atherosclerotic lesions. Aortic samples were analysed for CD36 mRNA expression. The aortas of cholesterol-fed rabbits showed typical atherosclerotic lesions, detected by macroscopic and microscopic examination, and exhibited an increase in CD36 mRNA expression. Vitamin E fully prevented cholesterol induced atherosclerotic lesions and the induction of CD36 mRNA expression. The effects observed at the level of CD36 scavenger receptor expression in vivo suggest an involvement of reduced foam cell formation in the protective effect of Vitamin E against atherosclerosis
Groupe VI : Géologie. Relations entre les nuages de poussières et la désertification en Afrique, par Pierre Ozer. Rapports des commissaires
No full textSouchez Roland, Delmer André, Pissart Albert. Groupe VI : Géologie. Relations entre les nuages de poussières et la désertification en Afrique, par Pierre Ozer. Rapports des commissaires. In: Bulletin de la Classe des sciences, tome 13, n°7-12, 2002. pp. 429-432
Age-dependent increase of collagenase expression can be reduced by alpha-tocopherol via protein kinase C inhibition.
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