Electric field and solvent model for Electrochemical SERS: excited-state and enhancement tuning

Being SERS a promising technique due to it potentially combining the well-known characterization prowess of Raman with the high sensitivity arising from nanoparticle-associated enhancement, 1 understanding the mechanisms due to which SERS differs from Normal Raman is key to accomplish effective applications of this technique. Following the consensus about the theoretical background that stablishes the enhancement mechanisms in SERS, 2 and focusing on electrode potential as a variable in Electrochemical (EC) SERS, for our work we have studied Pyridine (Py) SERS spectra modelling an EC-SERS nanostructured surface through an Ag 6 cluster in different orientations, with an electric field parallel to the Ag 6 -Py axis reproducing electrode potential, as depicted in Figure 1. The objective of such model is to simulate Pyridine SERS spectra and rationalizing these results based on well-established properties, accounting for symmetry considerations, coupling terms and the influence of the solvent on the system to carry out a straightforward understanding of SERS enhancement mechanisms. Our results are able to effectively reproduce the main relative intensities of Pyridine SERS spectra, shedding light on the influence of the aforementioned properties on the calculated lineshapes and intensities.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

Modelling potential dependent surface-enhanced raman scattering: electric field and charged cluster dual model

The computation of electrochemical systems is very challenging because of the many variables involved. Among them, the effect of the electrode potential is particularly complex to be introduced in atomistic models. In this work, we propose a model where the surface excess of charge has been modelled with the tetrahedral-like clusters [Ag19]+, [Ag20]0 and [Ag19]-. We then modulate the effect of other surface charges implicitly as an external electric field and correlated a calculated magnitude like the electric charge on the adsorbate with the electrode potential, a purely experimental one. This model is tested with the potential-dependent Surface-Enhanced Raman Scattering (SERS) of pyridine. Namely, we investigated the changes in the Raman shifts and relative intensities due to the potential, and evaluated the different contributions (electromagnetic, charge-transfer) to the SERS spectra. Our preliminary results nicely reproduce the experimental trends and reveal that enhancement factors up to 10 to the 7th are achieved when the charge-transfer state interact with the bright local excitations of the metal cluster

Electric field and charged cluster dual model for Potential Depdendent Surface-Enhanced Raman Spectroscopy

The computation of electrochemical systems is very challenging because of the many variables involved.1 Among them, the effect of the electrode potential is particularly complex to be introduced in atomistic models. In this work, we propose a model where the surface excess of charge has been modelled with the tetrahedral-like clusters [Ag19]+, [Ag20]0 and [Ag19]-. We then modulate the effect of other surface charges implicitly as an external electric field and correlated a calculated magnitude like the electric charge on the adsorbate with the electrode potential, a purely experimental one. This model is tested with the potential-dependent Surface-Enhanced Raman Scattering (SERS) of pyridine. Namely, we investigated the changes in the Raman shifts and relative intensities due to the potential, and evaluated the different contributions (electromagnetic, charge-transfer) to the SERS spectra. Our preliminary results nicely reproduce the experimental trends and reveal that enhancement factors up to 107 are achieved when the charge-transfer state interact with the bright local excitations of the metal cluster.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tec

The search for the perfect race: ideas on procreation, old age and eugenics

Objetivo. El presente artículo se deriva de la investigación “Dilemas éticos para la toma de decisiones en tiempos de guerra”, la cual responde a los lineamientos y metas de la línea de investigación en ‘Biopolítica’ del Doctorado en Bioética de la Universidad Militar Nueva Granada; línea de investigación que tiene como objetivos buscar e indagar sobre los dilemas éticos en la toma de decisiones en tiempos de guerra. Metodología. La metodología fue un análisis histórico interpretativo de la tendencia a buscar la raza perfecta, lo que se conoce como prácticas eugenésicas, esto se busca especialmente en tiempos de guerra, y sus consecuencias para la sociedad. Resultados y conclusiones. Dentro de los dilemas éticos en tiempos de guerra, se analizarán decisiones en el III Reich”; dentro de los dilemas éticos del principio de la vida está la eugenesia como tendencia a perfeccionar la raza a costa incluso de la eliminación de los enfermos, los viejos, los individuos con necesidades especiales mentales y físicas. Este artículo expone el tratamiento de las ideas de eugenesia en el Tercer Reich, durante la época de Adolfo Hitler en el poder.Objective. This article is derived from the “Ethical dilemmas for decision-making in wartime.” research Project which responds to the guidelines and goals of the research line in ‘Bio-politics’ from the Doctorate program in Bioethics at Universidad Militar Nueva Granada, a line of research that aims to find and investigate the ethical dilemmas for decision-making in wartime. Methodology. The methodology was an interpretative historical analysis of the tendency to search for the perfect race which is known as eugenic practices this seeks especially in wartime. Results and conclusions. Decisions taken during the thrid Reich are analyzed. Eugenics, as a tendency to perfect the race even at the cost of eliminating the sick, the elderly, the individuals with mental and physical special needs, is part of the ethical dilemmas of the beginning of life. This article discusses the treatment of the ideas of eugenics in the Third Reich during Adolf Hitler’s time in power

About the Unexpected Structure and Properties of Molecules Bonded to Metal Nanoclusters.

SERS (Surface-Enhanced Raman Scattering) is a very powerful technique to gain insight into the nature of metal-molecule hybrids on a molecular level. We show the results of combining SERS and theoretical calculations (1) to analyze the subtle electronic structure of metal-molecule (M-A) interfaces, especially to study the dependence of their structure and properties on applied electric potentials or fields. An example of this is the huge efficiency of the potential (EV) in tuning the energies (E) of metal-molecule charge transfer (CT) states. An equivalence between both quantities is expected on the basis of classical electrochemistry (G=E/EV=1 eV/V) but observed energy gains up to G=4 or 5 eV/V can be explained by combining the dependence of the CT energies (E) on the excess of charge of the metal (qeff) (see Graphical Abstract) and the capacitive enhancement located at metallic nanostructures (2). Moreover, theoretical calculations predict a dual electronic structure of the M-A surface complex in the case of charged molecules bonded to charged metals. These two types of surface states of the same hybrid system are of a very different nature and are selected by the sign of the metal charge (qeff). It is predicted that a single M-A complex can be very strongly bonded (chemisorbed) or form weak and very polarizable complexes (physisorbed) depending on the charges of both the ionic species and the surface excess of the metal which is modulated by the applied potential. These two types of complexes determine the properties of the overall system in the ground electronic state, like the behavior of the wavenumbers of the CN stretching band adsorbed on metals (3-4), as well as in excited states, like the forward and reverse metal-molecule CT states of the isonicotinate anion bonded to positive (chemisorbed, G~0 eV/V) or negative (physisorbed, high G) silver clusters (5), respectively (see Graphical Abstract).Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

El Control Interno en la Comisión Estatal de Vivienda, Suelo e Infraestructura del Estado de Chihuahua y la Importancia de la Auditoria Interna

El Sistema de Control Interno es esencial en toda organización, brinda seguridad razonable en la ejecución de procesos y en el cumplimiento de los objetivos y metas. La Auditoría Interna mejora la efectividad de las actividades agregando valor a las operaciones mediante recomendaciones resultado de la evaluación al control interno. El objetivo del presente estudio fue analizar el sistema de Control Interno en la Comisión Estatal de Vivienda, Suelo e Infraestructura del Estado de Chihuahua y la importancia de la creación de un Área de Auditoría Interna. La metodología utilizada fue de naturaleza mixta, de tipo aplicada, el diseño no experimental, transeccional-descriptivo realizado en el periodo de enero a abril 2022, de modo empírico, con apoyo bibliográfico, la unidad de análisis fueron los jefes de departamento adscritos al organismo. Los resultados obtenidos fueron que la Comisión Estatal de Vivienda, Suelo e Infraestructura del Estado de Chihuahua si cuenta con control interno sin embargo el grado de cumplimiento es nivel bajo debido a que no existe un área de auditoría interna que realice actividades de revisión y evaluación.   The Internal Control System is essential in any organization, it provides reasonable security in the execution of processes and in the fulfillment of objectives and goals. Internal Audit improves the effectiveness of activities by adding value to operations through recommendations resulting from the evaluation of internal control. The aim of this study was to analyze the Internal Control system in the Comisión Estatal de Vivienda, Suelo e Infraestructura del Estado de Chihuahua and the importance of creating an Internal Audit Area. The methodology used was of a mixed nature, of an applied type, the non-experimental, transactional-descriptive design carried out in the period from January to April 2022, in a field mode with bibliographic support, the unit of analysis was all the department heads assigned to the agency. The results obtained were that the State Housing, Land and Infrastructure Commission of the State of Chihuahua does have internal control, however the degree of compliance is low because there is no internal audit area that carries out review and evaluation activities

El arca de las tres llaves en el entorno digital: recursos audiovisuales para la enseñanza de la Archivística en el siglo XXI

Depto. de Historia de América y Medieval y Ciencias HistoriográficasFac. de Geografía e HistoriaFALSEsubmitte

The influence of electrode potential on SERS through the electronic structure of nanostructured metal-cyanide interfaces

Experimental and theoretical calculations confirm the existence of two different electronic structures of a surface complex formed by a particular molecule bonded to charged metal electrodes, clusters, or nanoparticles. Each electronic structure of the metal-molecule hybrid system is selected by sign of the surface excess of charge of the metal at potentials more negative or positive than its potential of zero charge (PZC). Surface-enhanced Raman scattering (SERS) of cyanine adsorbed on a silver electrode shows two regions, which are selected by the voltage and characterized by the differentiated response of the vibrational wavenumbers of the ν(CN) stretching band. The combination between the experimental SERS and theoretical DFT calculations has allowed for relating the two regions to chemisorbed (C-hybrid, region A) and physisorbed (P-hybrid, region B) surface complexes, where cyanide is bonded through the carbon on top of a single silver atom of the surface. The electrode potential selects one or another type of electronic structure of the system, which are of different nature having a differentiated response to the applied voltage. Electric potentials tune smoothly the wavenumbers, bond energies, and injected charges of the P-hybrid at more negative potentials than PZC, but the very strong C-hybrid prevents significant changes of these properties at positive excesses of charge. The existence of the dual electronic structure of metal-molecule interfaces might require reinterpreting experiments that are usually discussed by resorting to, for instance, the reorientation of the adsorbate, the formation of complexes with different stoichiometries, the existence of nonequivalent local sites on the surface, or to instrumental artifacts. Moreover, this dual behaviour also determines the properties and responses of technological devices where metal-molecule interfaces are involved.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

Effect of Resistant Dextrin on Intestinal Gas Homeostasis and Microbiota

Previous studies have shown that a resistant dextrin soluble fibre has prebiotic properties with related health benefits on blood glucose management and satiety. Our aim was to demonstrate the effects of continuous administration of resistant dextrin on intestinal gas production, digestive sensations, and gut microbiota metabolism and composition. Healthy subjects (n = 20) were given resistant dextrin (14 g/d NUTRIOSE ®, Roquette Frères, Lestrem, France) for four weeks. Outcomes were measured before, at the beginning, end, and two weeks after administration: anal evacuations of gas during daytime; digestive perception, girth, and gas production in response to a standard meal; sensory and digestive responses to a comfort meal; volume of colonic biomass by magnetic resonance; taxonomy and metabolic functions of fecal microbiota by shotgun sequencing; metabolomics in urine. Dextrin administration produced an initial increase in intestinal gas production and gas-related sensations, followed by a subsequent decrease, which magnified after discontinuation. Dextrin enlarged the volume of colonic biomass, inducing changes in microbial metabolism and composition with an increase in short chain fatty acids-producing species and modulation of bile acids and biotin metabolism. These data indicate that consumption of a soluble fibre induces an adaptative response of gut microbiota towards fermentative pathways with lower gas productio

Nuevos recursos didácticos para el aula digital: tradiciones antroponímicas del Madrid multicultural

Este proyecto plantea un trabajo centrado en la elaboración, aplicación docente y evaluación de instrumentos didácticos on-line sobre antroponimia y sus tradiciones en el Madrid multicultural. Persigue aglutinar materiales educativos a disposición de los alumnos a través del Campus Virtual de la Universidad Complutense de Madrid y de las páginas web de los dos Grupos de Investigación implicados en el equipo: “Onomástica y deonomástica” (www.ucm.es/onomastica-deonomastica) y “Organización territorial y administrativa del concejo de Madrid (ss. XIII-XVIII)” (www.ucm.es/documad/). La temática permite ofrecer a todos nuestros alumnos nuevas perspectivas y materiales sobre los estudios antroponímicos que, aunque enmarcados por lo general en el ámbito filológico, han sido también con frecuencia abordados por los historiadores