DSpace Collection: ArtÃculos en publicaciones ISI - Universidad de Talca
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Nonlinearly charged Lifshitz black holes for any exponent z > 1
http://dspace.utalca.cl/handle/1950/10216
Title: Nonlinearly charged Lifshitz black holes for any exponent z > 1<br/><br/>Authors: Alvarez, A.; Ayon-Beato, E.; Gonzalez, HA.; Hassaine, M.<br/><br/>Abstract: Charged Lifshitz black holes for the Einstein-Proca-Maxwell system with a negative cosmological constant in arbitrary dimension D are known only if the dynamical critical exponent is fixed as z = 2(D - 2). In the present work, we show that these configurations can be extended to much more general charged black holes which in addition exist for any value of the dynamical exponent z > 1 by considering a nonlinear electrodynamics instead of the Maxwell theory. More precisely, we introduce a two-parametric nonlinear electrodynamics defined in the more general, but less known, so-called ( , P )-formalism and obtain a family of charged black hole solutions depending on two parameters. We also remark that the value of the dynamical exponent z = D - 2 turns out to be critical in the sense that it yields asymptotically Lifshitz black holes with logarithmic decay supported by a particular logarithmic electrodynamics. All these configurations include extremal Lifshitz black holes. Charged topological Lifshitz black holes are also shown to emerge by slightly generalizing the proposed electrodynamics.<br/><br/>Description: Univ Talca, Inst Matemat & Fis, Talca, Chile; Hassaine, M (Hassaine, Mokhtar)Morphometric and phytochemical characterization of chaura fruits (Gaultheria pumila): a native Chilean berry with commercial potential
http://dspace.utalca.cl/handle/1950/10214
Title: Morphometric and phytochemical characterization of chaura fruits (Gaultheria pumila): a native Chilean berry with commercial potential<br/><br/>Authors: Villagra, E.; Campos-Hernandez, C.; Caceres, P.; Cabrera, G.; Bernardo, Y.; Arencibia, A.; Carrasco, B.; Caligari, PDS.; Pico, J.; Garcia-Gonzales, R.<br/><br/>Abstract: Background: For the first time, a morphometric characterization of chaura (Gaultheria pumila) fruits has been conducted between natural populations growing in the Villarrica National Park, Araucania Region, Chile. Chaura is a native Ericaceae from Chile that produces aromatic and tasty fruits which could be of agricultural interest. Results: To influence the decision for a further domestication of G. pumila, both the fruit sizes (indicator of productivity) and the nutritional properties of the fruits have been determined from different subpopulations. Samples were a total of 74 plants and 15 fruits per plant which were randomly harvested following its natural distribution around the Villarrica volcano. Altogether, fresh weight, shape, color, diameter in the pole and the equatorial dimensions were determined as phenotypic traits of the G. pumila fruits. Meanwhile the total soluble solids, anthocyanin and pectin contents were calculated as nutritional traits of the Chaura fruits. Results showed a high phenotypic diversity between the sampled population with three main fruit shapes and three predominant colors. The round shapes were the most abundant, whereas a significant correlation was found among fruit size with weight and color. The highest fresh weight (597.3 mg), pole diameter (7.1 mm) and equatorial diameter (6.5 mm) were estimated in the pink color fruits. Conclusions: The total amount of anthocyanin was higher in red fruits, while the maximum pectin content was obtained in the round white fruits. Overall results must pave the way for a further domestication and introduction of the Chaura species in the agro-productive system in Chile.<br/><br/>Description: Univ Talca, Inst Biol Vegetal & Biotecnol, Talca, Chile; Caligari, PDS (Caligari, Peter D. S.); Pico, J (Pico, Jose)Tracking Endogenous Amelogenin and Ameloblastin In Vivo
http://dspace.utalca.cl/handle/1950/10210
Title: Tracking Endogenous Amelogenin and Ameloblastin In Vivo<br/><br/>Authors: Jacques, J.; Hotton, D.; De la Dure-Molla, M.; Petit, S.; Asselin, A.; Kulkarni, AB.; Gibson, CW.; Brookes, SJ.; Berdal, A.; Isaac, J.<br/><br/>Abstract: Research on enamel matrix proteins (EMPs) is centered on understanding their role in enamel biomineralization and their bioactivity for tissue engineering. While therapeutic application of EMPs has been widely documented, their expression and biological function in non-enamel tissues is unclear. Our first aim was to screen for amelogenin (AMELX) and ameloblastin (AMBN) gene expression in mandibular bones and soft tissues isolated from adult mice (15 weeks old). Using RT-PCR, we showed mRNA expression of AMELX and AMBN in mandibular alveolar and basal bones and, at low levels, in several soft tissues; eyes and ovaries were RNA-positive for AMELX and eyes, tongues and testicles for AMBN. Moreover, in mandibular tissues AMELX and AMBN mRNA levels varied according to two parameters: 1) ontogenic stage (decreasing with age), and 2) tissue-type (e. g. higher level in dental epithelial cells and alveolar bone when compared to basal bone and dental mesenchymal cells in 1 week old mice). In situ hybridization and immunohistodetection were performed in mandibular tissues using AMELX KO mice as controls. We identified AMELX-producing (RNA-positive) cells lining the adjacent alveolar bone and AMBN and AMELX proteins in the microenvironment surrounding EMPs-producing cells. Western blotting of proteins extracted by non-dissociative means revealed that AMELX and AMBN are not exclusive to mineralized matrix; they are present to some degree in a solubilized state in mandibular bone and presumably have some capacity to diffuse. Our data support the notion that AMELX and AMBN may function as growth factor-like molecules solubilized in the aqueous microenvironment. In jaws, they might play some role in bone physiology through autocrine/paracrine pathways, particularly during development and stress-induced remodeling.<br/><br/>Description: Univ Talca, Dept Stomatol, Unit Periodontol, Talca, Chile; Jacques, J (Jacques, Jaime)Abiotic stresses differentially affect the expression of 0-methyltransferase genes related to methoxypyrazine biosynthesis in seeded and parthenocarpic fruits of Vitis vinifera (L.)
http://dspace.utalca.cl/handle/1950/10209
Title: Abiotic stresses differentially affect the expression of 0-methyltransferase genes related to methoxypyrazine biosynthesis in seeded and parthenocarpic fruits of Vitis vinifera (L.)<br/><br/>Authors: Vallarino, JG.; Gainza-Cortes, F.; Verdugo-Alegria, C.; Gonzalez, E.; Moreno, YM.<br/><br/>Abstract: MPs (3-alkyl-2-methoxypyrazines) are grape-derived aroma compounds that are associated with detrimental herbaceous flavours in some wines. It is well known that several viticultural and environmental parameters can modulate MP concentrations in grapes, although comprehensive molecular studies have not been conducted in this field. Although the biosynthesis pathway of MPs has not been fully elucidated, four Vitis vinifera 0-methyltransferase genes (VvOMT1-4) have been related to be involved in MP biosynthesis. We assessed whether different abiotic stresses induction have an impact on MP levels in grapes and wines from seeded and parthenocarpic fruits. Our results show that the timing of VvOMT3 expression is associated with the period of MPs accumulation in seeded fruits during both abiotic stresses, whereas no association was found in parthenocarpic fruits. These results are discussed in the context of how different viticultural practices can modulate VvOMT gene expression, which has a direct impact on MPs levels in wines. (C) 2014 Elsevier Ltd. All rights reserved.<br/><br/>Description: Univ Talca, Fac Ciencias Agr, Ctr Tecnol Vid & Vino, Talca, Chile; Vallarino, JG (Vallarino, Jose G.); Verdugo-Alegria, C (Verdugo-Alegria, Claudio); Moreno, YM (Moreno, Yerko M.)