Fundamentals and Applications of Surface-Enhanced Raman Spectroscopy (SERS)

When a molecule is adsorbed on some metallic nanostructured surfaces such as silver, copper or gold, it can undergo an enormous enhancement of the Raman signal giving rise to the so called Surface-Enhanced Raman Scattering (SERS). The high sensitivity of this effect allows an accurate structural study of adsorbates at very low concentrations. The SERS effect has historically been associated with the substrate roughness on two characteristic length scales. Surface roughness on the 10 to 100 nm length scale supports localized plasmon resonances which are considered as the dominant enhancement mechanism of SERS (Electromagnetic Enhancement Mechanism: SERS-EM). It is usually accepted that these electromagnetic resonances can increase the scattered intensity by an average factor of ca. 104 to 107. A secondary mechanism often thought to require atomic scale roughness is referred to as Charge Transfer (CT) Enhancement Mechanism (SERS-CT). This mechanism involves the photoinduced transfer of an electron from the metal to the adsorbate or vice versa and involves new electronic excited CT states which result from adsorbate–substrate chemical interactions. It is also estimated that such SERS-CT mechanism can enhance the scattering cross-section by a factor of ca. 10 to 102. These two mechanisms can operate simultaneously, depending on the particular systems and experimental conditions, making difficult to recognize each one and to estimate their relative magnitude in a particular spectrum.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

Kinetic study of thermal de-chlorination of PVC containing waste

With the increasing of plastics content in solid waste, both municipal and industrial, also increases the interest in its use as an energy source. Some of these wastes are an important potential source of energy and might be valorized using the pyrolysis or gasification processes. However, the presence of high chlorine contents in its composition prevents its management by a thermal process, as consequence of toxic compounds production and their release to the atmosphere. The present work asses a possible process for treating PVC-containing wastes in an environmentally friendly way. It is based on the effective de-chlorination of PVC-containing wastes through a pyrolysis process at low temperature before the carbonaceous residue from PVC-containing wastes being subject to a subsequent thermal treatment for energetic valorization.QREN (NORTE-01-0202-FEDER-011447

Toward a test of angular momentum coherence in a twin-atom interferometer

We present a scheme well-suited to investigate quantitatively the angular momentum coherence of molecular fragments. Assuming that the dissociated molecule has a null total angular momentum, we investigate the propagation of the corresponding atomic fragments in the apparatus. We show that the envisioned interferometer enables one to distinguish unambiguously a spin-coherent from a spin-incoherent dissociation, as well as to estimate the purity of the angular momentum density matrix associated with the fragments. This setup, which may be seen as an atomic analogue of a twin-photon interferometer, can be used to investigate the suitability of molecule dissociation processes -- such as the metastable hydrogen atoms H($2^2 S$)-H($2^2 S$) dissociation - for coherent twin-atom optics.Comment: 6 pages, 3 Figures. Final version accepted for publication in Europhysics Letter

Parto y distocias en la perra y en la gata

El conocimiento de la fisiología normal del parto, eutocia, resulta indispensable para reconocer y, por lo tanto, establecer un adecuado plan de actuación clínica ante un parto patológico o distócico. En la primera parte de este artículo revisamos los mecanismos del parto en la perra y en la gata poniendo especial interés en aquellos aspectos de mayor trascendencia clínica; posteriormente estudiamos el parto patológico, su diagnóstico y las técnicas obstétricas que debemos emplear para resolver el problema que plantea un parto distócico en los animales de compañía.An adequate knowledge of the physiological parturition, eutocya, results essential in order to recognize and then establishing an accurate plan of clinicalperformance, to cope with the pathological whelping or dystocia. That's why in the first part of this article the mechanism of parturition in the bitch and the queen are reviewed, watching especiaUythose aspects of clinical significance; after this we study the pathological parturition, its identification and the obstetrical techniques to use in order to get successin the resolution of the trouble that a dystocia in companion animals represents

Experiencias relacionadas con la evolución del método didáctico: incorporación del uso de la plataforma moodle, videos educativos y cd interactivos

Globalization and the explosion of the Information and Communication Technologies (ICT) have yet to be integrated into existing models of management and education. The performance of the teaching activity needs to approach reflectively the pedagogic model under which the education of a discipline will be arranged. In this work a teaching experience is exposed in the University of Malaga

Nanostructured multilayer compartments : towards multifunctionality and ‘‘cell-like’’ hierarchical complexity

In living organisms, there are phenomena that require the presence of specific biomolecules with distinct function and in variable concentrations at a given time, such as the healing and regeneration of tissue and organ lesions. In this work, we propose the use of a compartmented drug delivery device for the multiple release of bioactive agents. It consists of nanostructured microcapsules confined within a millimetric container that can be easily handled, mimicking the concept of cells which possess organelles with specialized functions. Each hierarchical structure was conceived using the layer-by-layer (LbL) method to form micro and macrocapsules that could individually carry either molecules and release them with distinct kinetics or magnetic nanoparticles (MNPs) to be used in targeted therapies. Furthermore, the internal microcontainers were constructed with a temperature-responsive elastin-like recombinamer (ELR) to further add smart properties to the proposed system. Sacrificial CaCO3 microparticles empty or entrapping either rhodamine or Fe3O4 MNPs were incubated in chitosan and ELR solutions using LbL for the conception of the microcapsules. Then, the microcapsules were suspended in alginate which was ionically crosslinked in CaCl2 drop-wise. Rhodamine could be encapsulated at this point in the alginate. The bead was coated with chitosan and alginate to build the external macrocapsule compartment. All structures were coated with 3 bilayers. The CaCO3 cores were chelated and the alginate beads liquefied using EDTA. Fluorescence microscopy using FITC and rhodamine markers showed a uniform distribution of the microcapsules within the macroreservoir. The release of rhodamine from either in the micro or macrocapsule was assessed at 25 and 37 °C in PBS. While the release from the macrocapsule follows a profile similar to that of traditional drug delivery systems, it is more sustained and delayed when released from the internal compartments. Such retention is more pronounced at 37 ºC (65% of release in comparison to 90%). This is due to the temperature responsive behavior of ELRs, which undergo a phase transition and make the LbL shell less permeable. For the magnetic response, the incorporation of the MNPs was observed by transmitted light microscopy. The attraction of the devices was observed by applying an external magnetic field along a defined trajectory. The results let foresee the use of such multilayer devices as compartmented structures to encapsulate growth factors, MNPs and stem cells for their controlled differentiation and maintenance or for guided regeneration of tissues and organs.Fundo Social Europeu (FSE)Fundação para a Ciência e a Tecnologia (FCT)Programa Diferencial de Potencial Humano (POPH

Early Carboniferous synorogenic basins evolution of the Ossa-Morena and

The stratigraphic record of the Early Carboniferous in Iberia reveals that synorogenic deposition was important and occurred simultaneously in basins influenced by extension and contraction with gravitational instability. In NW Iberia (Galicia – Trás-os-Montes Zone) contraction was dominant and the deposition took place in a forebulge outwards from the nappe stacking front. Here, synorogenic deposits were strongly affected by folding and thrusting as they were imbricated and incorporated in the allochthonous pile. In a different way, in SW Iberia (Ossa-Morena Zone) synorogenic deposition was influenced by extension and happened simultaneously with the onset of significant magmatism

Parametrized variational principles in dynamics applied to the optimization of dynamic models of plates

We investigate the use of Parametrized Variational Principles (PVP) in linear structural dynamics. Our main objective is to assess whether the free parameters can be used to enhance the accuracy of dynamic models on a fixed mesh. Consistent, boundary-consistent and lumped mass matrices are defined within the framework of the PVP. The accuracy provided by three different mass matrices in the computation of plate frequencies is numerically studied. A method to update the free parameters on an element by element basis to improve the dynamic model is presented. Numerical experiments that characterize that improvement for the vibration and transient-response analysis of plates are presented. These experiments suggest that such update is primarily beneficial for modes in the intermediate frequency range