88 research outputs found

    A Microcontroller Based System for Controlling Patient Respiratory Guidelines

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    The need of making improvements in obtaining (in a non-invasive way) and monitoring the breathing rate parameters in a patient emerges due to (1) the great amount of breathing problems our society suffer, (2) the problems that can be solved, and (3) the methods used so far. Non-specific machines are usually used to carry out these measures or simply calculate the number of inhalations and exhalations within a particular timeframe. These methods lack of effectiveness and precision thus, influencing the capacity of getting a good diagnosis. This proposal focuses on drawing up a technology composed of a mechanism and a user application which allows doctors to obtain the breathing rate parameters in a comfortable and concise way. In addition, such parameters are stored in a database for potential consultation as well as for the medical history of the patients. For this, the current approach takes into account the needs, the capacities, the expectations and the user motivations which have been compiled by means of open interviews, forum discussions, surveys and application uses. In addition, an empirical evaluation has been conducted with a set of volunteers. Results indicate that the proposed technology may reduce cost and improve the reliability of the diagnosis.Ministerio de Economía y Competitividad TIN2016-76956-C3-2-RMinisterio de Economía y Competitividad TIN2015-71938-RED

    A DFTand TD-DFTApproach to the Understanding of Statistical Kinetics in Substitution Reactions of M3Q4 (M=Mo, W; Q=S, Se) Cuboidal Clusters

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    For many years it has been known that the nine water molecules in [M3Q4(H2O)9]4+ cuboidal clusters (M= Mo, W; Q=S, Se) can be replaced by entering ligands, such as chloride or thiocyanate, and kinetic studies carried out mainly on the substitution of the first water molecule at each metal centre reveal that the reaction at the three metal centres occurs with statistical kinetics; that is, a single exponential with a rate constant corresponding to the reaction at the third centre is observed instead of the expected threeexponential kinetic trace. Such simplification of the kinetic equations requires the simultaneous fulfilment of two conditions: first that the three consecutive rate constants are in statistical ratio, and second that the metal centres behave as independent chromophores. The validity of those simplifications has been checked for the case of the reaction of [Mo3S4(H2O)9]4+ with Cl by using DFT and TD-DFT theoretical calculations. The results of those calculations are in agreement with the available experimental information, which indicates that the H2O ligands trans to the m-S undergo substitution much faster than those trans to the m3-S. Moreover, the energy barriers for the substitution of the first water molecule at the three metal centres are close to each other, the differences being compatible with the small changes in the numerical values of the rate constants required for observation of statistical kinetics. TD-DFT calculations lead to calculated electronic spectra, which are in reasonable agreement with those experimentally measured, but the calculations do not indicate that the three metal centres behave as independent chromophores, although the mathematical conditions required for simplification of the kinetic traces to a single exponential are reasonably well fulfilled at certain wavelengths. A re-examination of the kinetics of the reaction by using global fitting procedures yields results, which are compatible with statistical kinetics, although an alternative interpretation in which substitution only occurs at a single metal centre under reversible conditions is also possible

    Fortaleciendo la lucha contra la moneda falsificada

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    La falta de contundencia de la Ley 599 de 2000, art. 274 (y en las sanciones que se imparten a partir de este) presenta dificultades a la hora de sancionar conductas que deberían ser punibles, como la posesión de ciertas cantidades de moneda falsificada. En el Código Penal Colombiano, el delito de tráfico de moneda falsificada se encuentra tipificado de la mano con los verbos rectores de adquirir, comercializar, recibir y circular, todas acciones que, de ser comprobadas, llevarían al individuo en cuestión a cumplir una condena de entre cuarenta y ocho (48) y ciento cuarenta y cuatro (144) meses de prisión. Sin embargo, son amplias las ocasiones en las que los individuos no son encontrados en flagrancia realizando la acción propia de alguno de aquellos verbos rectores, sino únicamente teniendo en su poder la moneda falsa, nacional o extranjera, situación que actualmente en Colombia no es fácil comprobar como delito. Esta situación acarrea problemáticas para la lucha del Estado colombiano contra el tráfico de moneda falsificada, ya que la posesión de esta en altas cantidades facilita la distribución de estas y su introducción en el mercado de bienes y servicios del país. Esta entrega se configura como una primera aproximación a la investigación del problema de investigación ya mencionado. Así pues, cabe mencionar que la pregunta problema de esta serie de entregas es ¿de qué manera la implementación de todas las herramientas judiciales posibles puede hacer más efectivas las sanciones derivadas del artículo 274 del Código Penal Colombiano por parte del operador jurídico? Esta pregunta se responderá tras la lectura, uso y compendio de fuentes primarias y secundarias propias de las ciencias jurídicas. Se hará remisión a fuentes primarias como los debates legislativos en los que se han discutido leyes y artículos de relevancia para la investigación, sentencias de las altas cortes, la jurisprudencia sobre moneda falsificada, entre otros. Además, las fuentes secundarias a utilizar serán, principalmente, aquellas propias de la academia del Derecho con el objetivo de reconocer qué se ha escrito sobre temas importantes para la investigación, reconocer referentes teóricos y jurídicos para el desarrollo de la investigación y apartados fundamentales como el marco teórico y el estado del arte.Universidad Libre - Facultad de Derecho - Maestría en Derecho Penal y Procesal Pena

    Combined kinetic and DFT studies on the stabilization of the pyramidal form of H3PO2 at the heterometal site of [Mo3M’S4(H2O)10]4+ clusters (M’= Pd, Ni)

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    Kinetic and DFT studies have been carried out on the reaction of the [Mo3M’S4(H2O)10]4+ clusters (M’= Pd, Ni) with H3PO2 to form the [Mo3M’(pyr-H3PO2)S4(H2O)9]4+ complexes, in which the rare pyramidal form of H3PO2 is stabilized by coordination to the M’ site of the clusters. The reaction proceeds with biphasic kinetics, both steps showing a first order dependence with respect to H3PO2. These results are interpreted in terms of a mechanism that involves an initial substitution step in which one tetrahedral H3PO2 molecule coordinates to M’ through the oxygen atom of the P=O bond, followed by a second step that consists in tautomerization of coordinated H3PO2 assisted by a second H3PO2 molecule. DFT studies have been carried out to obtain information on the details of both kinetic steps, the major finding being that the role of the additional H3PO2 molecule in the second step consists in catalysing a hydrogen shift from phosphorus to oxygen in O-coordinated H3PO2, which is made possible by its capability of accepting a proton from P-H to form H4PO2 + and then transfer it to the oxygen. DFT studies have been also carried out on the reaction at the Mo centres to understand the reasons that make these metal centres ineffective for promoting tautomerizatio

    Measuring the diversification of energy sources: The energy mix

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    In this paper we explore the concept of concentration/diversification of energy sources. Concentration is identified by a number that represents the energy mix, i.e., the vector of the share quota of each energy source in total consumptions. We construct a new concentration index which is a mathematical distance and economically interpretable and apply it to the world's major economies for the period between 1965 and 2018. We find that the diversification process has been considerable, intense, and widespread, and has presented different territorial patterns.Funding for open access charge: Universidad de Málaga / CBU

    Fe(II) complexes of pyridine-substituted thiosemicarbazone ligands as catalysts for oxidations with hydrogen peroxide

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    La reacción de tres complejos [FeII(TSC)2], donde TSC es una ligando de tipo tiosemicarbazona sustituido por piridina, con H2O2 en acetonitrilo no permitía acumular los correspondientes complejos de Fe(III), [FeIII(TSC)2]+. En su lugar, se generaba una mezcla de especies de Fe(II) diamagnéticas de bajo espín. Según los espectros obtenidos por espectrometría de masas, estas especies eran el resultado de la adición secuencial de hasta cinco átomos de oxígeno al complejo. Esta capacidad para la adición de átomos de oxígeno sugirió que dichas especies podrían ser activas para la transferencia de átomos de oxígeno a sustratos externos. Por ello, se evaluó la capacidad de estos complejos para la oxidación de tioanisol y estireno empleando H2O2 como oxidante inicial. Los complejos fueron activos tanto en la oxidación de tioanisol a su sulfóxido como en la de estireno a benzaldehído, con escalas temporales que indicaban la participación de las especies intermedias que contenían los átomos de oxígeno añadidos. Curiosamente, los ligandos libres y el complejo [Zn(Dp44mT)2] también catalizaban la sulfoxidación selectiva del tioanisol, pero eran ineficaces para catalizar la oxidación del estireno a benzaldehído. Estos hallazgos abren nuevas vías para el desarrollo de catalizadores metálicos basados en tiosemicarbazonas en procesos de oxidación de gran interés

    Benchmarking of DFTmethods using experimental free energies and volumes of activation for the cycloaddition of alkynes to cuboidalMo(3)S(4)clusters

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    Here, the kinetics of the concerted [3 + 2] cycloaddition reaction between the [Mo3(μ3‐S)(μ‐S)3Cl3(dmen)3]+ (dmen = N,N′‐dimethyl‐ethylenediamine) ([1]+) cluster and various alkynes to form dithiolene derivatives is thoroughly studied, with measurements at different temperatures and pressures allowing the determination of the free energies and volumes of activation. These parameters, together with the available single‐crystal X‐ray diffraction structures, are used to test a number of commonly used density functional theory (DFT) methods from Jacob's ladder, as well as the effects associated with the size of the basis sets, the way in which solvent effects are taken into account, or the inclusion of dispersion effects. Overall, a protocol that leads to average deviations between experimental and computed ΔV‡ and ΔG‡ values similar to the uncertainty of the experimental measurements is obtained

    Base-Free Catalytic Hydrogen Production from Formic Acid Mediated by a Cubane-Type Mo3S4 Cluster Hydride

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    Formic acid (FA) dehydrogenation is an attractive process in the implementation of a hydrogen economy. To make this process greener and less costly, the interest nowadays is moving toward non-noble metal catalysts and additive-free protocols. Efficient protocols using earth abundant first row transition metals, mostly iron, have been developed, but other metals, such as molybdenum, remain practically unexplored. Herein, we present the transformation of FA to form H2 and CO2 through a cluster catalysis mechanism mediated by a cuboidal [Mo3S4H3(dmpe)3]+ hydride cluster in the absence of base or any other additive. Our catalyst has proved to be more active and selective than the other molybdenum compounds reported to date for this purpose. Kinetic studies, reaction monitoring, and isolation of the [Mo3S4(OCHO)3(dmpe)3]+ formate reaction intermediate, in combination with DFT calculations, have allowed us to formulate an unambiguous mechanism of FA dehydrogenation. Kinetic studies indicate that the reaction at temperatures up to 60 °C ends at the triformate complex and occurs in a single kinetic step, which can be interpreted in terms of statistical kinetics at the three metal centers. The process starts with the formation of a dihydrogen-bonded species with Mo–H···HOOCH bonds, detected by NMR techniques, followed by hydrogen release and formate coordination. Whereas this process is favored at temperatures up to 60 °C, the subsequent β-hydride elimination that allows for the CO2 release and closes the catalytic cycle is only completed at higher temperatures. The cycle also operates starting from the [Mo3S4(OCHO)3(dmpe)3]+ formate intermediate, again with preservation of the cluster integrity, which adds our proposal to the list of the infrequent cluster catalysis reaction mechanisms.Funding for open access charge: CRUE-Universitat Jaume

    Benchmarking of DFT methods using experimental free energies and volumes of activation for the cycloaddition of alkynes to cuboidal Mo3S4 clusters

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    Here, the kinetics of the concerted [3 + 2] cycloaddition reaction between the [Mo3(μ3‐S)(μ‐S)3Cl3(dmen)3]+ (dmen = N,N′‐dimethyl‐ethylenediamine) ([1]+) cluster and various alkynes to form dithiolene derivatives is thoroughly studied, with measurements at different temperatures and pressures allowing the determination of the free energies and volumes of activation. These parameters, together with the available single‐crystal X‐ray diffraction structures, are used to test a number of commonly used density functional theory (DFT) methods from Jacob's ladder, as well as the effects associated with the size of the basis sets, the way in which solvent effects are taken into account, or the inclusion of dispersion effects. Overall, a protocol that leads to average deviations between experimental and computed ΔV and ΔG values similar to the uncertainty of the experimental measurements is obtained

    Efficient (Z)-selective semihydrogenation of alkynes catalyzed by air-stable imidazolyl amino molybdenum cluster sulfides

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    Imidazolyl amino cuboidal Mo3(μ3-S)(μ-S)3 clusters have been investigated as catalysts for the semihydrogenation of alkynes. For that purpose, three new air-stable cluster salts [Mo3S4Cl3(ImNH2)3]BF4 ([1]BF4), [Mo3S4Cl3(ImNH(CH3))3]BF4 ([2]BF4) and [Mo3S4Cl3(ImN(CH3)2)3]BF4 ([3]BF4) have been isolated in moderate to high yields and fully characterized. Crystal structures of complexes [1]PF6 and [2]Cl confirm the formation of a single isomer in which the nitrogen atoms of the three imidazolyl groups of the ligands are located trans to the capping sulfur atom which leaves the three bridging sulfur centers on one side of the trimetallic plane while the amino groups lie on the opposite side. Kinetic studies show that the cluster bridging sulfurs react with diphenylacetylene (dpa) in a reversible equilibrium to form the corresponding dithiolene adduct. Formation of this adduct is postulated as the first step in the catalytic semihydrogenation of alkynes mediated by molybdenum sulfides. These complexes catalyze the (Z)-selective semihydrogenation of diphenylacetylene (dpa) under hydrogen in the absence of any additives. The catalytic activity lowers sequentially upon replacement of the hydrogen atoms of the N–H2 moiety in 1+ without reaching inhibition. Mechanistic experiments support a sulfur centered mechanism without participation of the amino groups. Different diphenylacetylene derivatives are selectively hydrogenated using complex 1+ to their corresponding Z-alkenes in excellent yields. Extension of this protocol to 3,7,11,15-tetramethylhexadec-1-yn-3-ol, an essential intermediate for the production of vitamin E, affords the semihydrogenation product in very good yield
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