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Burgos, Spain

The University of Burgos is a public university in the Spanish city of Burgos with about 10,000 students studying over 30 different undergraduate degrees, over 20 PhD Programmes, as well as several Official Masters and other graduate courses. Wikipedia.

Aparicio S.,University of Burgos | Atilhan M.,Qatar University
Journal of Physical Chemistry C | Year: 2012

The microscopic structure of choline benzoate and choline salicylate at uncharged hydrophobic graphite surfaces, and around and inside single-walled carbon nanotubes with (10,10) and (15,15) armchair configurations, was analyzed using molecular dynamics simulations. The reported results show remarkable structural differences in the vicinity of graphite surfaces (up to 20 Å) in comparison with bulk ionic liquids. A remarkable increase of density in the region up to 6 Å close to graphite surface is inferred, which is more remarkable for benzoate and salicylate anions than for choline cation. Aromatic rings in benzoate and salicylate anions lie flat at the graphite surface. Choline-based ionic liquids show cylindrical distributions around carbon nanotubes, with the filling of the nanotube depending on the nanotube diameter. The distributions inside the nanotubes rely on the nanotube diameter and are not uniform for the studied anions and cations. Aromatic rings in benzoate and salicylate cations stay parallel to nanotube surfaces. © 2012 American Chemical Society. Source

Gale P.A.,University of Southampton | Perez-Tomas R.,University of Barcelona | Quesada R.,University of Burgos
Accounts of Chemical Research | Year: 2013

In this Account, we discuss the development of new lipid bilayer aniontransporters based on the structure of anionophoric natural products (the prodigiosins) and purely synthetic supramolecular systems. We have studied the interaction of these compounds with human cancer cell lines, and, in general, the most active anion transporter compounds possess the greatest anti-cancer properties.Initially, we describe the anion transport properties of synthetic mol-ecules that are based on the structure of the family of natural products known as the prodiginines. Obatoclax, for example, is a prodiginine derivative with an indole ring that is currently in clinical trials for use as an anti-cancer drug. The anion transport properties of the compounds were correlated with their toxicity toward small cell human lung cancer GLC4 cells. We studied related compounds with enamine moieties, tambjamines, that serve as active transporters. These molecules and others in this series could depolarize acidic compartments within GLC4 cells and trigger apoptosis. In a study of the variation of lipophilicity of a series of these compounds, we observed that, as log P increases, the anion transport efficiency reaches a peak and then decreases.In addition, we discuss the anion transport properties of series of synthetic supramolecular anion receptor species. We synthesized trisureas and thioureas based on the tren backbone, and found that the thiourea compounds effectively transport anions. Fluorination of the pendant phenyl groups in this series of compounds greatly enhances the transport properties. Similar to our earlier results, the most active anion transporters reduced the viability of human cancer cell lines by depolarizing acidic compartments in GLC4 cells and triggering apoptosis.In an attempt to produce simpler transporters that obey Lipinski's Rule of Five, we synthesized simpler systems containing a single urea or thiourea group. Once again the thiourea systems, and in particular a thiourea with a pendant indole group, transported anions efficiently. A series of related compounds containing a pendant trifluoromethyl group showed enhanced transport and significant anticancer properties.Researchers still need to determine of the exact mechanism of how these compounds depolarize acidic organelles within cancer cells. However, this work shows that these transporters based upon both natural products and purely synthetic supramolecular systems transport anions, depolarize acidic compartments within cancer cells and trigger apoptosis. © 2013 American Chemical Society. Source

The experimental linear viscoelastic and steady-state shear data over a broad concentration range of several aqueous semi-flexible polysaccharide solutions can be quantitatively predicted by the multimode Phan-Thien Tanner, Giesekus, and extended Pom-Pom non-linear viscoelastic models using a single set of parameters. Experimental data from an aqueous solution of the polysaccharide guar galactomannan (Mw =1.12× 106 g/mol), aqueous phosphopolysaccharide "viilian" solution excreted by Lactococcus lactis subspecies cremoris SBT 0495 (Mw =2× 106 g/mol), and aqueous Propionibacterium acidi-propionici polysaccharide solution (Mw ≈ 106 g/mol) are taken from literature. A master curve can be constructed by shifting data from different concentrations over the horizontal and vertical axes. A simple model to describe the concentration dependence of the relaxation time and plateau modulus over the entire concentration range is presented. Transient shear viscosity data are quantitatively and first normal stress coefficient are qualitatively predicted for the guar galactomannan solution. Due to their proven performance in finite element simulations, these non-linear viscoelastic constitutive equations could help us to improve predictive modeling of time-dependent complex flow problems for polysaccharide solutions with variations in concentration and temperature in the spatial domain using only a single set of parameters. However, as a previous step, the performance of additional rheological experiments in simple flows, i.e., transient and steady-state extensional measurements, is recommended. © 2010 The Society of Rheology. Source

Alfonso I.,CSIC - Institute of Advanced Chemistry of Catalonia | Quesada R.,University of Burgos
Chemical Science | Year: 2013

The control of ion transport and homeostasis is a critical function of living organisms. In this perspective, an overview of different synthetic systems capable of facilitating the transmembrane transport of ions along with the biological activity exerted by these compounds is presented. Examples of both cation selective and anion selective transporters are highlighted. The potential future applications of these systems in the treatment of conditions derived from the dysregulation of natural ion transport mechanisms and the development of new antimicrobials and anticancer drugs are discussed. © 2013 The Royal Society of Chemistry. Source

Davis J.T.,University of Maryland University College | Okunola O.,University of Maryland University College | Quesada R.,University of Burgos
Chemical Society Reviews | Year: 2010

Anions cannot diffuse passively through biological membranes and membrane-bound proteins mainly govern the transmembrane movement of these charged species. The use of synthetic compounds that are able to facilitate the transmembrane transport of anions is a fascinating and burgeoning topic. The study of facilitated anion transport across lipid bilayers is an emerging field in supramolecular and bioorganic chemistry. In this critical review we describe the recent research progress in this area, focusing on literature published during the years 2007-2009. An overview of the assays that are used in the transmembrane transport of anions is also included (158 references). © 2010 The Royal Society of Chemistry. Source

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