About Helices and Solvents: VCD and more

Intermolecular forces drive self-organization of molecules, which is ultimately the origin of most the physical and chemical phenomena in Nature. Molecules able to interact themselves by non-covalent forces, as hydrogen bonding and/or hydrophobic attractions, usually form macrostructures in condensed phases (solid, solution). The properties of these aggregates depend of three main factors: the structural and chemical features of the molecules, the nature of intermolecular forces and the environment. The first two drive aggregation in solid state, while in solution the role of the solvent become determinant as it can induce a variety of structural effects on the aggregation behaviour of the solute. In the case of chiral molecules, this property is transferred to the aggregates and supramolecular chirality appears. Here we present our research on chiral molecules that self-organize in solution forming helical structures. We use VCD as the main chiroptical tool, but also supported by other chiroptical spectroscopies (ECD, ROA) and theoretical modelling. In our first steps, we studied the effect of modulating the environmental settings on the helices. Thus, helix handedness was proved highly and reversibly dependent on factors as pH or ionic strength in peptide-mimetic hydrogelators. We also observe how the initial conditions (concentration, temperature) were capable of controlling the helix structure of oligo-p-phenylene-based polymers towards kinetic or thermodynamics pathways. Besides, the structure of the helices can also be the consequence of direct solvent-solute interactions. In this way, we have demonstrated that an achiral solvent can act as a template for chiral organization of N-heterotriangulenes-based organogelators, thus showing the different levels of complexity of the hierarchical organization of supramolecular polymers. But the solvent-helix interactions can be bidirectional. As a nice example, we recorded chiral signals which can be only assigned to the organization of the solvent molecules around helical aggregates of phenylglycine functionalized poly(phenylacetylene)s. The solvent molecules thus form a first solvation shell to which the helix chirality is transferred. The helices would act therefore as a template of the solvent molecules, and the chirality of this external helix would be fully controlled by the solute.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

Chiroptical Spectroscopy of C3 Molecules

The relevance of molecules with C3 symmetry comes from the fact of many of them, upon assembling as columnar helical macromolecules, are ideal platform for electro-optical devices, for example as liquid crystals. The properties of these devices are highly dependent of the structure of the bulk aggregates, and consequently they can be controlled by modifying the position and nature of the stereocenters in the molecular building blocks. In this work we present an electronic and vibrational chiroptical study on a series of star-shaped molecules based on the octopolar C3-symmetric 1,3,5-(phenylene-ethynylene)-benzene block.Universidad de Málaga, Campus de Excelencia Internacional Andalucía Tec

SEQUENTIAL INDUCTION OF CHIRALITY IN POLY(PHENYLACETYLENE)S

Several hierarchical levels of chirality have been detected in functionalized poly(phenylacetylene)s (PPA).1 In this work we have studied the chirality induction throughout these levels in PPA functionalized with phenylglycine methyl ester groups, Fig. 1.2 These pendant groups force the PPA chain to lose its planar all-transoid shape to form helical structures. The chiral seed of the pendants, [(R)- or (S)-], dictates the preferent handedness of the helices, both the internal polyacetylene helical covalent backbone and the external helix formed by the side pendants which forms a complementary helix or counter-helix. In this work, we afford a full assessment of the interconnection between stereocenter and helix sources of chirality and the action of these polymers as chiral templates of other supra-molecular structures with inherited chiral properties. We then used VCD spectroscoy to demonstrate the chiral induction from the stereogenic centers to the backbone helix and from this to the pendant helix, which are largely promoted by two mechanisms: steric effects and hydrogen bonding. In addition, the VCD spectra supported that the helical setup of the pendants induces the solvent DMSO molecules to adopt a solvation helix around the polymer, thus proving how an achiral solvent becomes chirally organized owing to the template effect of the covalent polymer helices. A similar effect was observed in DMSO solutions of the monomeric units. Interestingly, this resulted in opposite helical sense to the one observed in the polymer with identical enantiomeric form.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

Tectono-stratigraphic basin evolution in the Tehuacán-Mixteca highlands, south western México

The morphological evolution of the basins in the Sierra Madre del Sur (SMS), southern México is poorly understood. This work explains for the first time the geomorphological development of the tectonic, fluvially-interconnected SMS basins named San Juan Raya (SJRb) and Zapotitlán (ZAPb). The evolution of the SJRb and ZAPb are analysed within the context of the transformations of the well-studied Tehuacán basin (TEHb). A new interpretation of a series of tectonic features of the TEHb valley area is also presented. Published geological data and extensive field work provided the basis for our geomorphological and evolutionary interpretation of basin evolution of this part of Mesoamerica during the late Cenozoic. Stratigraphic and sedimentary records suggest that after the late Cretaceous-early Cenozoic orogeny the TEHb and ZAPb were closed basins, and that the TEHb graben system was activated during the Paleogene as a response to the dominant regional NW-SE trending faults. We propose that the ZAPb and SJRb formed sequentially during the Neogene as a result of new E-W, N-S and NE-SW faults. The continuation of the TEHb extension during the Oligocene widened its lowland area and allowed the formation of an extensive lake. No alluvial or fluvial records of this interval are found in the ZAPb and SJRb. No sedimentation rather than formation and subsequent erosion of such sediments is supported by the basin morphology and by the absence of re-worked alluvial deposits at the outlet area where both connect to the TEHb. By middle to late Miocene the TEHb lost its endorheic configuration, ending the lake-type deposition while new faults initiated the opening of the ZAPb. Intensive tectonics, alluvial deposition and the confinement of the Tehuacán lake to the north sector of this basin characterised the Pliocene. During the late Pliocene to the early Pleistocene the formation of the SJRb was initiated. Quaternary faulting related to basin extension along the north watershed of the SJRb and ZAPb is supported by independent data on the biogeography of the cactus Mammillaria pectinifera. We introduce the idea that the departure from the regional NW-SE fault alignment that formed the major Miocene basins to a more local E-W trend that formed Neogene-Quaternary basins was probably a response to the latest post-orogenic relaxation of the crust in the Mixteca terrane

Ameva: An autonomous discretization algorithm

This paper describes a new discretization algorithm, called Ameva, which is designed to work with supervised learning algorithms. Ameva maximizes a contingency coefficient based on Chi-square statistics and generates a potentially minimal number of discrete intervals. Its most important advantage, in contrast with several existing discretization algorithms, is that it does not need the user to indicate the number of intervals. We have compared Ameva with one of the most relevant discretization algorithms, CAIM. Tests performed comparing these two algorithms show that discrete attributes generated by the Ameva algorithm always have the lowest number of intervals, and even if the number of classes is high, the same computational complexity is maintained. A comparison between the Ameva and the genetic algorithm approaches has been also realized and there are very small differences between these iterative and combinatorial approaches, except when considering the execution time.Ministerio de Educación y Ciencia TSI2006-13390-C02-02Junta de Andalucía P06-TIC-0214

Determination of ketorolac in the effluent from a hospital treating plant and kinetics study of its physiolic degradation

In this work, two specific, sensitive and rapid analytical methods were developed. One of them for the determination of ketorolac in a hospital wastewater treatment plant where there is no interference with other organic substances; the other one for the determination of the degradation kinetics in aqueous medium. Ketorolac was extracted from wastewater samples through solid phase extraction cartridges (SPE), then it was identified and quantified by high performance liquid chromatography (HPLC). Ketorolac was detected in concentrations between 0.1376 and 0.2667 µg/L. Photolytic degradation was performed on aqueous solutions of ketorolac tromethamine, reference substance, at a concentration of 50 µg/mL. Samples were in direct contact with ultraviolet light in a dark chamber, equipped with two mercury lamps (254 nm) at a radiation source of 15W. The results of the photolytic degradation were adjusted to a first-order model, obtaining a half-life of 4.8 hrs

Service-Oriented Device Integration for Ubiquitous Ambient Assisted Living Environments

As a result of the increment of population in countries of Europe, a lot of efforts from European Authorities are coming from. In our research we want to bring forward a suite of developments related to build a ubiquitous AAL (Ambient Assisted Living) environment. We consider that recent approaches are based on ad-hoc technologies so its application is in this context isolated just in one domain of application. Our approach addresses to a reliable services platform for heterogeneous devices integration. On this basis we want to consider as well, the underlying benefits that a Service-oriented platform is giving to us in our Ambient Assisted Living Applications.Ministerio de Educación y Ciencia TSI2006-13390-C02-02Junta de Andalucía TIC-2141Ministerio de Industria, Turismo y Comercio TSI-020400-2008-11

Qualitative Comparison of Temporal Series. QSI

In this paper, the study of systems that evolve in time by means of the comparison of time series is proposed. An improvement in the form to compare temporal series with the incorporation of qualitative knowledge by means of qualitative labels is carried out. Each label represents a rank of values that, from a qualitative perspective, may be considered similar. The selection of labels of a single character allows the application of algorithms of string comparison. Finally, an index of similarity of time series based on the similarity of the obtained strings is defined.Comisión Interministerial de Ciencia y Tecnología DPI2001-4404-EComisión Interministerial de Ciencia y Tecnología DPI2000-0666-C02-0