175 research outputs found
Low-Temperature Solution-Processed Electron Transport Layers for Inverted Polymer Solar Cells
© 2016 WILEY-VCH Verlag GmbH & Co. KGaA, WeinheimProcessing temperature is highlighted as a convenient means of controlling the optical and charge transport properties of solution processed electron transport layers (ETLs) in inverted polymer solar cells. Using the well-studied active layer – poly(3-hexylthiophene-2,5-diyl):indene-C60 bisadduct – the influence of ETL processing temperatures from 25 to 450 °C is shown, reporting the role of crystallinity, structure, charge transport, and Fermi level (EF) on numerous device performance characteristics. It has been determined that an exceptionally low temperature processed ETL (110 °C) increases device power conversion efficiency by a factor greater than 50% compared with a high temperature (450 °C) processed ETL. Modulations in device series and shunt resistance, induced by changes in the ETL transport properties, are observed in parallel to significant changes in device open circuit voltage attributed to changes on the EF of the ETLs. This work highlights the importance of interlayer control in multilayer photovoltaic devices and presents a convenient material compatible with future flexible and roll-to-roll processes
Fatty acid and triacylglycerol compositions of milk thistle seeds growing wild in Tunisia (Silybum marianum L.)
The milk thistle plant grows in many regions in Tunisia; however, there is no literature regarding their oil composition. In this study, oil content, fatty acids and triacylglycerols compositions of milk thistle seeds growing wild in Tunisia were determined. The oil content was 30.5%, thus milk thistle seeds could be exploited as natural new source of oil. Among the fatty acids, linoleic acid had the highest percentage (59.98%) followed by oleic acid (21.26%) and palmitic acid (12.74%). The extracted oil from milk thistle seeds is rich in polyunsaturated fatty acids (60.37%). Various molecular species of TAGs were detected and the major forms were LLL (22.30%), OLL (20.40%), PLL (17.31%), POL (14.30%), and OOL (7.90%). It can be concluded that milk thistle seed oil has a characteristic TAG pattern as compared with these elucidated for olive oil and soybean oil
Resultats du traitement chirurgical de l’otospongiose notre experience a propos de 310 cas
Introduction : Le traitement de l’otospongiose est chirurgical. Plusieurs facteurs peuvent intervenir dans l’indication opératoire ou influencer les résultats fonctionnels. L’objectif de notre étude est d’évaluer nos résultats audiométriques et d’étudier les facteurs prédictifs de l’échec fonctionnel. Matériel et méthodes : Il s’agit d’une étude rétrospective à propos de 310 oreilles opérées pour otospongiose, sur une période de 21 ans (1985-2005). On a effectué une analyse des résultats audiométriques à partir des audiogrammes postopératoires faits à 3 mois, à 1an et au dernier contrôle. Nous avons ensuite étudié 8 facteurs pouvant être prédictifs de l’échec fonctionnel. Ce dernier était défini par un Rinne résiduel post-opératoire (RRPO) > 10 dB.Résultats : Le RRPO était en moyenne de 7,9 dB avec des extrêmes de 5 dB à 33 dB. La fermeture du Rinne a été obtenue dans 87,3% des cas. Après étude multivariée avec régression logistique, nous avons retenu 2 facteurs indépendants significativement prédictifs de l’échec fonctionnel : un stade audiométrique III ou IV d’Aubry (OR : 19,06/p : 0,0001) et un Rinne post-opératoire précoce supérieur à 35 dB (OR : 4 ,01/p : 0,0025). Conclusion : Une audiométrie post-opératoire précoce serait intéressante pour dépister précocement un échec chirurgical d’une part et pour préjuger du résultat fonctionnel définitif d’autre part. Un stade audiométrique III ou IV d’ Aubry, prédictif certes d’un moins bon résultat fonctionnel, ne contre-indique pas la chirurgie qui permettra entre autres une meilleure adaptation audio- prothétique.Mots-clés : otospongiose - chirurgie - résultats – facteurs prédictif
Cambios en la composiciĂłn de esteroles del aceite de cardo mariano (Silybium marianum L.) durante la maduraciĂłn de la semilla
In this study, the total lipid content and sterol compositions were determined during the development of milk thistle seeds. The oil content increased to a maximum value of 36±1.7% and then declined to reach a value of 30.5±0.9% at full maturity. The sterol content of milk thistle seeds was affected by the ripening degree of the seeds. At the early stages of seed maturation, Δ7-stigmastenol was the most abundant sterol followed by β-sitosterol. However, at full maturity, β-sitosterol was the most predominant sterol (46.50±0.8%). As the seed developed, campesterol and stigmasterol amounts increased, while Δ7-avenasterol content decreased. It can be concluded that milk thistle seed oil has a characteristic sterol pattern comparable to the ones elucidated for olive oil and corn oil. The extracted oil from milk thistle seeds is rich in phytosterols and could be used in food preparation and human nutrition.En este estudio se determinaron la composiciĂłn de lĂpidos totales y esteroles durante el desarrollo de semillas de cardo mariano. El contenido de aceite incrementĂł a un valor máximo de 36±1,7% y posteriormente disminuyĂł hasta alcanzar un valor de 30,5±0,9% cuando la maduraciĂłn fue completa. El contenido de esteroles de las semillas de cardo mariano se ve afectado por el grado de maduraciĂłn de las semillas. En las primeras etapas de la maduraciĂłn de las semillas el Δ7-estigmastenol fuĂ© el esterol más abundante, seguido de β-sitosterol. Sin embargo en plena madurez, β-sitosterol fue el esterol predominante (46,50±0,8%). A medida que las semillas se desarrollan las cantidades de campesterol y estigmasterol aumentan, mientras que el contenido Δ7-avenasterol disminuye. Se puede concluir que el aceite de semillas de cardo mariano tiene un patrĂłn caracterĂstico de esteroles en comparaciĂłn con lo especificado para los aceites de oliva y de maĂz. El aceite extraĂdo de las semillas del cardo mariano es rica en fitoesteroles y podrĂa ser utilizado en la preparaciĂłn de alimentos y en nutriciĂłn humana
Interqubit coupling mediated by a high-excitation-energy quantum object
We consider a system composed of two qubits and a high-excitation-energy
quantum object used to mediate coupling between the qubits. We treat the entire
system quantum mechanically and analyze the properties of the eigenvalues and
eigenstates of the total Hamiltonian. After reproducing well-known results
concerning the leading term in the mediated coupling, we obtain an expression
for the residual coupling between the qubits in the off state. We also analyze
the entanglement between the three objects, i.e. the two qubits and the
coupler, in the eigenstates of the total Hamiltonian. Although we focus on the
application of our results to the recently realized parametric-coupling scheme
with two qubits, we also discuss extensions of our results to
harmonic-oscillator couplers, couplers that are near resonance with the qubits
and multi-qubit systems. In particular, we find that certain errors that are
absent for a two-qubit system arise when dealing with multi-qubit systems.Comment: 15 pages (two-column
Bioactive Lipids, Antibacterial, Hypoglycaemic, and Antioxidant Potentials of Immature and Mature Vicia faba L. Seeds Cultivated in Tunisia
Both the immature and mature Vicia faba L. seeds are used for human consumption. However, there is a lack of information on the phytochemical composition and the potent biological properties of the immature seeds. The aim of the present study was to establish the profile of bioactive lipids as well as the antibacterial, antioxidant, and α-amylase and α-glucosidase inhibitory capacities of the immature and mature Vicia faba L. seeds. The studied petroleum ether extracts contain different bioactive compounds such as β-sitosterol, lupeol, β-amyrin, α-tocopherol, and γ-tocopherol. The extracts of the immature seeds exhibited higher antioxidant and antibacterial activities than those of mature ones. All tested extracts exerted higher inhibition on α-glucosidase than α-amylase. The immature seeds appeared as promising sources of natural antioxidants, antibacterial compounds, and α-amylase and α-glucosidase inhibitors. Thus, the immature Vicia faba L. seeds have a great potential as functional foods providing health beneficial properties
Fatty acid and triacylglycerol compositions of milk thistle seeds growing wild in Tunisia ( Silybum marianum
Microwave saturation of the Rydberg states of electrons on helium
We present measurements of the resonant microwave excitation of the Rydberg
energy levels of surface state electrons on superfluid helium. The temperature
dependent linewidth agrees well with theoretical predictions and is very small
below 300 mK. Absorption saturation and power broadening were observed as the
fraction of electrons in the first excited state was increased to 0.49, close
to the thermal excitation limit of 0.5. The Rabi frequency was determined as a
function of microwave power. The high values of the ratio of the Rabi frequency
to linewidth confirm this system as an excellent candidate for creating qubits.Comment: 4 pages, 4 figure
Direct Measurement of the System-Environment Coupling as a Tool For Understanding Decoherence and Dynamical Decoupling
Decoherence is a major obstacle to any practical implementation of quantum
information processing. One of the leading strategies to reduce decoherence is
dynamical decoupling --- the use of an external field to average out the effect
of the environment. The decoherence rate under any control field can be
calculated if the spectrum of the coupling to the environment is known. We
present a direct measurement of the bath coupling spectrum in an ensemble of
optically trapped ultracold atoms, by applying a spectrally narrow-band control
field. The measured spectrum follows a Lorentzian shape at low frequencies, but
exhibits non-monotonic features at higher frequencies due to the oscillatory
motion of the atoms in the trap. These features agree with our analytical
models and numerical Monte-Carlo simulations of the collisional bath. From the
inferred bath-coupling spectrum, we predict the performance of well-known
dynamical decoupling sequences: CPMG, UDD and CDD. We then apply these
sequences in experiment and compare the results to predictions, finding good
agreement in the weak-coupling limit. Thus, our work establishes experimentally
the validity of the overlap integral formalism, and is an important step
towards the implementation of an optimal dynamical decoupling sequence for a
given measured bath spectrum.Comment: 9 pages, 6 figure
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