http://www.recercat.cat:80/handle/2072/152142 Tue, 21 May 2013 05:09:29 GMT 2013-05-21T05:09:29Z http://www.recercat.cat:80/bitstream/id/34213/ http://www.recercat.cat:80/handle/2072/152142 http://www.recercat.cat:80/handle/2072/202160 Bicelles: new nano systems for skin applications Barbosa Barros, Lucyanna; Rodriguez, Gelen; Cócera Núñez, Mercedes; Rubio, Laia; Estelrich i Latràs, Joan; Maza Ribera, Alfonso de la; López Serrano, Olga Bicellar systems are lipid nanostructures formed by long- and short-chained phospholipids dispersed in aqueoussolution. Because of their attractive combination of lipid composition, small size and morphological versatility, bicellesbecame new targets for skin research. Bicelles modify the skin biophysical parameters and modulate the skin barrier function acting as enhancers for drug penetration. Moreover, these aggregates have the ability to penetrate through the narrowintercellular spaces of the skin stratum corneum and to reinforce its lipid lamellae. Their structures allows for the incorporation of different molecules that can be carried through the skin layers. Theremarkable versatility of bicelles is their most important characteristic, which makes it possible their use in different fields.These aggregates represent new nanosystems for skin applications. In this work we provide an overview of the main properties ofbicelles and their effects on the skin.; Podeu consultar el llibre complet a: http://hdl.handle.net/2445/32393 http://www.recercat.cat:80/handle/2072/202160 http://www.recercat.cat:80/handle/2072/182485 The impact of theoretical chemistry in Biology Orozco López, Modesto; Luque Garriga, F. Xavier Els avenços en les bases dels mètodes teòrics i l'espectacular desenvolupament de la potència de càlcul han fet possible progressar enormement en el somni dels fundadors de la química, és a dir, ser capaços d'estudiar amb mètodes computacionals el conjunt de processos químics. Actualment, la química teòrica està completant el darrer avenç: intentar esdevenir l'eina més recent per a comprendre la naturalesa química dels éssers vius. Aquesta revisió pretén mostrar com els mètodes de la química teòrica, originalment desenvolupats per a examinar molècules petites en fase gas, han evolucionat per a assolir la complexa descripció de sistemes biològics. http://www.recercat.cat:80/handle/2072/182485 http://www.recercat.cat:80/handle/2072/179527 Molecular simulations of globins: Exploring the relationship between structure, dynamics and function Forti, Flavio; Boechi, Leonardo; Novo de Oliveira, Ana; Bikiel, Damian; Arroyo, Pau; Nadra, Alejandro; Capece, Luciana; Bidon-Chanal Badia, Axel; Martí, Marcelo A.; Estrín, Darío; Luque Garriga, F. Xavier The discovery in the last two decades of novel members of the globin superfamily has challenged the conventional view about the structure and function of globins. Thus, peculiar structural differences are expected to have direct influence on properties related to ligand migration, binding affinity and heme reactivity. Molecular simulations are a valuable tool to gain insigth into the molecular mechanisms that underlie those structural differences, and their relationship with the diversity of functional roles. In this work, the impact of molecular simulations in exploring the linkage between structure, dynamics and function is highlighted for three representative cases: the migration of ligands through the protein matrix of truncated hemoglobins, the modulation of binding affinity by heme distortion in protoglobin, and finally the functional implications due to the equilibrium between penta- and hexacoordination of the heme with distal histidine in neuroglobin.; Podeu consultar el llibre complet a: http://hdl.handle.net/2445/32392 http://www.recercat.cat:80/handle/2072/179527 http://www.recercat.cat:80/handle/2072/172492 MMPBSA decomposition of the binding energy throughout a molecular dynamics simulation of Amyloid-Beta (Aß10-35) aggregation Campanera Alsina, Josep Maria; Pouplana, Ramon Recent experiments with amyloid-beta (Aß) peptides indicate that the formation of toxic oligomers may be an important contribution to the onset of Alzheimer's disease. The toxicity of Aß oligomers depend on their structure, which is governed by assembly dynamics. However, a detailed knowledge of the structure of at the atomic level has not been achieved yet due to limitations of current experimental techniques. In this study, replica exchange molecular dynamics simulations are used to identify the expected diversity of dimer conformations of Aß10-35 monomers. The most representative dimer conformation has been used to track the dimer formation process between both monomers. The process has been characterized by means of the evolution of the decomposition of the binding free energy, which provides an energetic profile of the interaction. Dimers undergo a process of reorganization driven basically by inter-chain hydrophobic and hydrophilic interactions and also solvation/desolvation processes. http://www.recercat.cat:80/handle/2072/172492 http://www.recercat.cat:80/handle/2072/152147 Aggregation of liposomes induced by calcium: A structural and kinetic study Roldán-Vargas, Sándalo; Martín-Molina, Alberto; Quesada-Pérez, Manuel; Barnadas Rodríguez, Ramon; Estelrich i Latràs, Joan; Callejas-Fernández,Joan In this work, the calcium-induced aggregation of phosphatidylserine liposomes is probed by means of the analysis of the kinetics of such process as well as the aggregate morphology. This novel characterization of liposome aggregation involves the use of static and dynamic light-scattering techniques to obtain kinetic exponents and fractal dimensions. For salt concentrations larger than 5 mM, a diffusion-limited aggregation regime is observed and the Brownian kernel properly describes the time evolution of the diffusion coefficient. For slow kinetics, a slightly modified multiple contact kernel is required. In any case, a time evolution model based on the numerical resolution of Smoluchowski's equation is proposed in order to establish a theoretical description for the aggregating system. Such a model provides an alternative procedure to determine the dimerization constant, which might supply valuable information about interaction mechanisms between phospholipid vesicles. http://www.recercat.cat:80/handle/2072/152147