Optoelectronic properties of triphenylamine based dyes for solar cell applications. A DFT study

Indexación: Scopus.GSM thanks to the Department of Chemistry at the Universidad Andres Bello, Concepcion, Chile. LHMH gratefully acknowledges financial support from CONACYT (Projects CB2015-257823) and to the Universidad Autónoma del Estado de Hidalgo.Dye-sensitized solar cells (DSSCs) based on triphenylamine (TPA) as a donor group linked with the acceptor cyanoacrylic acid electron acceptor by 2,2'-bithiophene as π-bridged (D-π-A) has been investigated by Density Functional Theory (DFT) at the B3LYP/6-311G(d,p) level of theory, to establish the conformational orientation of cyanoacrylic acid group as well as evaluate the effect of planarizing the 2,2'-bithiophene unit in position 3 and 3' by electron withdrawing or donor groups on the electronic structure properties of ground and doping(n,p) states. Also, the Time Dependent Density Functional Theory (TD-DFT) at the CPCM-TD-CAM-B3LYP//CAM-B3LYP/6-311G(d,p) level of theory were selected to modulate the electronic absorption spectra and charge-transfer capabilities of the molecules analyzed in the present work. The results indicate that adding an auxiliary donor or withdrawing group to the 2,2'-bithiophene in the (D-π-A) arrangement allow to modify the LUMO's energy of the dyes, while the HOMO's energy is slightly affected. © 2018 Sociedade Brasileira de Quimica. All rights reserved.http://quimicanova.sbq.org.br/imagebank/pdf/AR20170232.pd

Molecular and morphological characterization of the grapevine cultivars “Italia” in the Ica and Cañete valleys (Peru)

The denomination of “Uva de Italia” or “Italia” is commonly used by growers to refer to a group of varieties used from the colonial times to making a brandy of Pisco with muscat aroma. Previous work have demonstrated that Uva de Italia corresponds in fact to the variety Muscat of Alexandria, a widely spread variety around the world and in South America. However, the distinction between “Italia Dorada” and “Italia Rosada” is usually made, in allusion to the color variations observed in the berries. Our aim was to characterize 5 samples collected in vineyards from the valleys of Ica and Cañete. The genotypes were identified using 13 molecular markers of nuclear simple sequence repeat, and 23 morphological descriptors according to OIV. Our results showed that four genotypes were identified as Muscat of Alexandria while the other corresponded to variety well-known in Argentina as Moscatel Rosado or Uva Pastilla in Chile respectively. Moscatel Rosado showed functionally female flowers, with variable berries size and color in the range from greenish yellow through pink. This is the first identification of Moscatel Rosado as a variety present in the Peruvian vineyards and would allow its use in the pisco industry with distinctive aromatic characteristics. Keywords: Italia, Muscat of Alexandria, Moscatel Rosado, variety identification, parentage analysis, microsatellites, Pisco

Selección de variables cuantitativas y clasificación de 22 acessiones de fríjol arbustivo (Phaseolus vulgaris L.).

La evaluación de 22 colectas y tres testigos de fríjol arbustivos procedentes de germoplasma de Corpoica en Mosquera, Colombia, permitió seleccionar variables que discriminan la variabilidad existente e identificar las colectas sobresalientes por parámetros morfológicos cuantitativos y componentes de rendimiento. Se seleccionaron las variables de mayor heredabilidad representadas por coeficiente de repetibilidad r 1 (Goodman y Paterniani, 1969), de las 24 variables cuantitativas en estudio, 14 cumplieron esta condición, las variables descartadas fueron las del estado de plántula, área foliar y rendimiento. El análisis por componentes principales de las 14 variables retenidas mostró como los tres primeros componentes explicaron el 88.49 por ciento de la variación total, donde los caracteres: días a floración, días a cosecha, peso de 100 semillas, número de semillas por vaina, ancho y longitud de la vaina, altura de cobertura, número de nudos, y longitud de epicotilo e hipocotilo fueron los que más aportaron a dicha variación. Las colectas del acervo Mesoamericano: Antioquia 21, Cauca 34 y Tolima 16, y del acervo Andino: Perú 5 (Poroto Largo) y Cundinamarca 148, presentaron el mejor comportamiento agronómico y alta variabilidad genética, por lo cual se considera de importancia en la conservación de su variabilidad y como posibles progenitoresFríjol-Phaseolus vulgari

Exenatide regulates pancreatic islet integrity and insulin sensitivity in the nonhuman primate baboon Papio hamadryas.

The glucagon-like peptide-1 receptor agonist exenatide improves glycemic control by several and not completely understood mechanisms. Herein, we examined the effects of chronic intravenous exenatide infusion on insulin sensitivity, β cell and α cell function and relative volumes, and islet cell apoptosis and replication in nondiabetic nonhuman primates (baboons). At baseline, baboons received a 2-step hyperglycemic clamp followed by an l-arginine bolus (HC/A). After HC/A, baboons underwent a partial pancreatectomy (tail removal) and received a continuous exenatide (n = 12) or saline (n = 12) infusion for 13 weeks. At the end of treatment, HC/A was repeated, and the remnant pancreas (head-body) was harvested. Insulin sensitivity increased dramatically after exenatide treatment and was accompanied by a decrease in insulin and C-peptide secretion, while the insulin secretion/insulin resistance (disposition) index increased by about 2-fold. β, α, and δ cell relative volumes in exenatide-treated baboons were significantly increased compared with saline-treated controls, primarily as the result of increased islet cell replication. Features of cellular stress and secretory dysfunction were present in islets of saline-treated baboons and absent in islets of exenatide-treated baboons. In conclusion, chronic administration of exenatide exerts proliferative and cytoprotective effects on β, α, and δ cells and produces a robust increase in insulin sensitivity in nonhuman primates

Evidence of Color Coherence Effects in W+jets Events from ppbar Collisions at sqrt(s) = 1.8 TeV

We report the results of a study of color coherence effects in ppbar collisions based on data collected by the D0 detector during the 1994-1995 run of the Fermilab Tevatron Collider, at a center of mass energy sqrt(s) = 1.8 TeV. Initial-to-final state color interference effects are studied by examining particle distribution patterns in events with a W boson and at least one jet. The data are compared to Monte Carlo simulations with different color coherence implementations and to an analytic modified-leading-logarithm perturbative calculation based on the local parton-hadron duality hypothesis.Comment: 13 pages, 6 figures. Submitted to Physics Letters

Measurement of the Isolated Photon Cross Section in p-pbar Collisions at sqrt{s}=1.96 TeV

The cross section for the inclusive production of isolated photons has been measured in p anti-p collisions at sqrt{s}=1.96 TeV with the D0 detector at the Fermilab Tevatron Collider. The photons span transverse momenta 23 to 300 GeV and have pseudorapidity |eta|<0.9. The cross section is compared with the results from two next-to-leading order perturbative QCD calculations. The theoretical predictions agree with the measurement within uncertainties.Comment: 7 pages, 5 figures, submitted to Phys.Lett.

Search for single top quarks in the tau+jets channel using 4.8 fb−1^{-1} of ppˉp\bar{p} collision data

We present the first direct search for single top quark production using tau leptons. The search is based on 4.8 fb$^{-1}$ of integrated luminosity collected in $p\bar{p}$ collisions at $\sqrt{s}$=1.96 TeV with the D0 detector at the Fermilab Tevatron Collider. We select events with a final state including an isolated tau lepton, missing transverse energy, two or three jets, one or two of them $b$ tagged. We use a multivariate technique to discriminate signal from background. The number of events observed in data in this final state is consistent with the signal plus background expectation. We set in the tau+jets channel an upper limit on the single top quark cross section of \TauLimObs pb at the 95% C.L. This measurement allows a gain of 4% in expected sensitivity for the observation of single top production when combining it with electron+jets and muon+jets channels already published by the D0 collaboration with 2.3 fb$^{-1}$ of data. We measure a combined cross section of \SuperCombineXSall pb, which is the most precise measurement to date.Comment: 12 pages, 5 figure

b-Jet Identification in the D0 Experiment

Algorithms distinguishing jets originating from b quarks from other jet flavors are important tools in the physics program of the D0 experiment at the Fermilab Tevatron p-pbar collider. This article describes the methods that have been used to identify b-quark jets, exploiting in particular the long lifetimes of b-flavored hadrons, and the calibration of the performance of these algorithms based on collider data.Comment: submitted to Nuclear Instruments and Methods in Physics Research

Measurement of Z/gamma*+jet+X angular distributions in ppbar collisions at sqrt{s}=1.96 TeV

We present the first measurements at a hadron collider of differential cross sections for Z+jet+X production in delta phi(Z, jet), |delta y(Z, jet)| and |y_boost(Z, jet)|. Vector boson production in association with jets is an excellent probe of QCD and constitutes the main background to many small cross section processes, such as associated Higgs production. These measurements are crucial tests of the predictions of perturbative QCD and current event generators, which have varied success in describing the data. Using these measurements as inputs in tuning event generators will increase the experimental sensitivity to rare signals.Comment: Published in Physics Letters B 682 (2010), pp. 370-380. 15 pages, 6 figure