Modelado de trampas de hidrocarburos aplicadas en el arranque en frío de vehículos de gasolina

En este trabajo, se ha profundizado en el conocimiento del proceso de adsorción de propano sobre zeolita ZSM-5 con el objetivo de establecer las bases para el desarrollo de trampas de hidrocarburos que presenten unas prestaciones adecuadas en la reducción de las emisiones de hidrocarburos durante el periodo de arranque en frío en vehículos de gasolina. Para ello, se han llevado a cabo experimentos del proceso de adsorción-desorción así como de ciclos de encendido en frío en las diferentes condiciones de concentración, temperatura y flujo volumétrico que tienen lugar en las trampas de hidrocarburos. A continuación, y mediante comparación con los resultados experimentales, se han simulado estos procesos como primer paso para conocer los fenómenos de transferencia de materia y transferencia de energía que tienen lugar sobre la zeolita seleccionada. La herramienta seleccionada para llevar a cabo esta simulación dinámica ha sido el módulo Adsorption de AspenTech. A través de los resultados obtenidos, se ha demostrado que el modelo de simulación es adecuado para representar el proceso de adsorción de hidrocarburos en zeolitas bajo diferentes condiciones de operación, lo que indica la versatilidad del modelo y su alto grado de precisión, que lo convierte en una herramienta muy útil para la optimización del proceso y su posible escalado a una trampa real

Síntesis, caracterización y aplicación de zeolitas CuHZSM-5 con porosidad jerarquizada para su uso como trampa de hidrocarburos durante el arranque en frío de motores

El presente proyecto fin de carrera tiene como objetivo final la creación de zeolitas jerárquicas para aplicarlas en la reducción de la contaminación ambiental producida por los hidrocarburos emitidos por los coches, en particular el propeno y el tolueno. Para conseguirlo se probaron zeolitas ZSM-5 como trampas de hidrocarburos. Estas zeolitas habían sido jerarquizadas previamente y luego intercambiadas con Cu(NO3)2•3H2O. La jerarquización de la porosidad consiste en la creación de mesoporos en la estructura de la zeolita inicialmente microporosa mediante la realización de un tratamiento alcalino, en este caso utilizando como base NaOH. Con este tratamiento se consigue disolver el silicio y extraerlo así de la estructura dando lugar a poros de mayor tamaño, los mesoporos. Para optimizar esa parte del proceso se fijó la concentración de la base y se variaron la duración y la temperatura (parámetros de mayor influencia). El ratio Si/Al también es fundamental cuando se realiza un tratamiento alcalino ya que numerosos estudios demuestran que la presencia del Al en la estructura inhibe la extracción del Si, con lo cual si se reduce el número de aluminios por silicio se consigue una mayor formación de mesoporos. Para estar seguros del éxito en la creación de mesoporosidad se realizaron experimentos con distintos ratios (Si/Al 25 y Si/Al 40) cuyos resultados podíamos comparar para sacar conclusiones. Por otro lado, se quería optimizar el intercambio con Cu(NO3)2•3H2O para obtener mejores resultados durante las pruebas en el reactor, ya que trabajos previos del equipo habían demostrado que el cobre incluido en la zeolita mejoraba las prestaciones de las trampas de hidrocarburos (HC). Para ello se probaron intercambios con distintas concentraciones de Cu(NO3)2•3H2O para dos zeolitas ZSM-5 distintas, una con ratio Si/Al 25, la otra con Si/Al 40. El ratio Si/Al es fundamental en el intercambio de cationes porque limita la cantidad de éstos que se puede introducir en los espacios que se forman entre la estructura. Una vez optimizado el proceso de Desilicación y establecida la concentración ideal para el intercambio con cobre, se inició la síntesis de las muestras de la investigación principal con las distintas condiciones para el tratamiento alcalino, dejando la zeolita en su forma NaZSM-5. Después se realizó un ataque ácido para eliminar el aluminio extraído de la estructura durante el tratamiento alcalino y así recuperar el ratio Si/Al disminuido tras la disolución del silicio. Para devolver la zeolita a su forma ácida es necesario realizar un intercambio con NH4NO3 y calcinar para obtener la forma HZSM5 que permite realizar el intercambio para incluir el cobre. Con los tratamientos terminados se probaron las zeolitas en un reactor de lecho fijo que simulaba las condiciones de un motor durante el arranque enfrío, este test se denomina CST (Cold Start Test). Por último, se caracterizaron, cristalinidad, morfología, porosidad y acidez y se realizaron análisis de los resultados obtenidos en los CST. Con todos los análisis se concluye que las condiciones óptimas de producción de la zeolita CuHZSM-5 mediante desilicación e intercambio iónico para su uso en gases de motores durante el arranque en frío son: un tratamiento alcalino con NaOH 0,2 M, a 65 °C durante 15 min, seguido de un ataque ácido con HCl 0,1 M y un intercambio iónico con Cu(NO3)2•3H2O 100 mM. La zeolita producida en estas condiciones no sólo mejora la capacidad de adsorción de la zeolita ZSM-5 microporosa sino también la actividad catalítica y por lo tanto, la capacidad de tratamiento de propeno y tolueno en su aplicación como trampa de HC

Development of a New Method for the Determination of Manganese, Cadmium, Mercury and Lead in Whole Blood and Amniotic Fluid by Inductively Coupled Plasma Mass Spectrometry

Environmental exposure to metals among women, revealed their adverse effects on pregnancy. During this stage, blood levels of some metals increase so research on heavy metals transference from the mother’s blood to the developing foetus is of special interest and much attention has been paid to this matter. The amniotic fluid can be considered as a valuable marker of this prenatal exposure to exogenous factors. The aim of this study was to develop a method for the simultaneous determination of Mn, Cd, Hg, and Pb in whole maternal blood and amniotic fluid by ICP-MS. Strategies were given to minimise memory effects related to mercury and two widespread digestion procedures (open-vessel and microwave-assisted) were compared. Several quality controls, such as methodological and reagent blanks, spiked samples and duplicates were used to test the goodness of the developed method. Once optimised, the method was applied for the monitoring of Mn, Cd, Hg and Pb in 15 maternal blood and amniotic fluid samples obtained at delivery after informed consent. This study establishes that heavy metals pass into and accumulate in amniotic fluid and maternal blood. Thus, mean concentrations of Mn were similar in the two biological fluids studied, 21.6 ng/mL in maternal blood and 20.5 ng/mL in amniotic fluid. Mean Cd and mercury levels in blood and amniotic fluid were 1.3 and 6.3 ng/mL and 3.4 and 3.8 ng/mL, respectively. Concentrations of Pb were 16.4 ng/mL in blood and 13.7 ng/mL in amniotic fluid. Further studies are needed to evaluate the long-term health effects derived from this exposure.Plan Propio of the University of SevilleFundación Farmacéutica Avenzoa

Some inferences on the mechanism of atmospheric gas/particle partitioning of polycyclic aromatic hydrocarbons (PAH) at Zaragoza (Spain)

Gas-particle partitioning of pollutants is an important mechanism determining atmospheric processing and its impact to environmental and human health. In this paper, the gas-particle partitioning of polycyclic aromatic hydrocarbons (PAH) has been studied with the aim of determining the main mechanism of PAH partitioning in Zaragoza (Spain) aerosols. To reach this goal, the ambient concentrations of PAH (gas and particle phase) collected in this city for one year period (2003-2004) have been analyzed. The partitioning between the particle and gas phases was studied according to three different models: the Junge adsorption model, the absorption into the organic matter model using the octanol-air (KOA) partition coefficient and the absorption into the organic matter plus the adsorption onto the soot carbon model using the soot-air (KSA) partition coefficients. Experimental gas/particle partition coefficients (KP) correlated well with the subcooled liquid vapour pressures (P0 L) of PAH but with slopes higher than the expected value of - 1. Experimental Kp values were well fit to the modelled ones when, in addition to absorption into organic matter, adsorption onto the soot carbon was considered. It could be concluded that the main partition mechanism in Zaragoza aerosols was explained by adsorption onto the soot carbon. However, Kp modelled values were affected by the different thermodynamic parameters related to soot types. The influence of the organic matter and elemental carbon fractions on the Kp modelling was also studied. The different particle characteristics, local factors, the presence of non exchangeable fraction and non equilibrium were considered like main keys to explain deviations of the experimental Kp values from predictions according to models.Authors would like to thank the Government of Aragón (DGA) for the grant to M.T.C and the Spanish Government for the JAE doctoral contract to J.M.L and for the Juan de la Cierva contract to M.V.N.Peer reviewe

Summer and spring elbow rashes is a variant of polymorphous light eruption: confirmation by photoprovocation and histopathology in a series of five cases

Background: Summer and spring eruptions on the elbows are a variant of polymorphous light eruption described on clinical and histopathological grounds; however, to our knowledge, they have not been confirmed by photobiological studies. Objective: Based on photobiological studies, this study aimed to demonstrate the involvement of ultraviolet-A (UVA) radiation in this variant of polymorphous light eruption occurring exclusively on the elbows. Methods: A series of five patients with polymorphous light eruption lesions on the elbows were included in our study. All patients underwent phototesting and photoprovocation of the skin lesions after exposure to a UVA light source [Philips UVA HPA lamp (400 W)]. All patients underwent punch biopsy and histopathological and immunohistochemical studies with anti-CD123. Results: In all the cases, UVA irradiation caused the appearance of skin lesions on the elbows with characteristic polymorphous light eruption. Histological data showed edema in the superficial dermis and a perivascular lymphocytic infiltrate compatible with polymorphous light eruption. Immunohistochemical staining for CD1-23 showed negative results. Conclusions: For the first time, photobiological photoprovocation studies demonstrated that repeated exposure to UVA radiation leads to the generation of skin lesions on the elbows, which are clinically and histologically consistent with summer and spring eruptions, confirming that elbow rash is a variant of polymorphous light eruptio

Effect of foot health-related quality of life in rural population: A case-control study

[Abstract] Background: Foot health problems can affect quality of life and general health producing a source of discomfort and pain. Low levels of foot health-related quality of life (HRQoL) are present in patients with foot disabilities, such as hallux valgus, plantar fasciitis, or minor toe deformities. Objective: The objective was to analyze the foot health status in patients with and without foot problems in a rural population and its relationship with quality of life. Material and methods: A prospective case-control study was developed with a sample of 152 patients, 76 subjects with podiatric pathologies and 76 without, in a rural population. HRQoL was measured through the SF-36 Health Questionnaire in the Spanish version. Results: The case group had a mean age of 49.18 ± 14.96 and the control group 44.16 ± 11.79. Regarding the score of the lowest levels of quality of life related to foot problems, the case group compared to the controls showed: for physical function (79.86 ± 26.38 vs. 92.63 ± 11 0.17, p < 0.001); for the physical role (73.68 ± 41.00 vs. 88.48 ± 27.51, p < 0.0022); for body pain (45.81 ± 27.18 vs. 73.68 ± 41.00, p < 0.035); and for general health (60.36 ± 30.58 vs. 68.71 ± 18.52, p < 0.047). The differences between groups were analyzed using the Mann-Whitney U test, which showed statistical significance (P < 0.05). Conclusions: In the rural population, people with foot pathologies present a worse quality of life compared to those who do not present foot pathology, especially for the health domains: physical function, physical role, body pain and health general

Translated and adaptation into Persian of the podiatric health questionnaire (PHQ)

[Abstract] The Podiatric Health Questionnaire (PHQ) is a foot health psicometric tool consisting of six items for measuring foot health status. Currently, PHQ has been adapted into Spanish. Thus, this research focused on develop the Persian translation and adaptation of the PHQ. The translation into Persian and test-retest reliability methods were applied from english version questionnarie. As regards to the total mark for each sub-scale, internal consistency and reliability were determined by the Cronbach α and intraclass correlation coefficient (ICC) with a confidence interval (CI) of 95%. High internal consistency was shown for the six sub-scales: a) walk with a Cronbach α of 0.775; b) hygiene and c) nail care with 0.789 and 0.796 respectively; d) foot on pain with 0.779; e) concern domain with 0.788; and f) quality of life with 0.798; and g) visual analogic scale with 0.803. Excellent test-retest reliability (ICC = 0.912 [95% CI = 0.845–0.950]) was shown for the total score. Conclusions: The persian version of the PHQ was shown to be a valid and reliable tool for an acceptable use in the Iran population

Influence of quality of life related to perceived foot health between in a rural an urban population: A case–control research

Foot problems are very common in the community. Studies indicate that between 18% and 63% of people have foot pain or stiffness and that foot problems have a large impact on people's functional decline and a significant detrimental impact on measures of quality of life related to health. The general objective of this research was to compare foot health in people from the rural population compared to people from the urban population and its relationship with quality of life. A case–control descriptive study was developed with a sample of 304 patients, 152 patients from the rural population and 152 patients from the urban population. Quality of life was measured through the SF-36 Health Questionnaire in its Spanish version. The rural population group had a mean age of 46.67 ± 13.69 and the urban population group 49.02 ± 18.29. Regarding the score of the lowest levels of quality of life related to foot problems, the rural population group compared to the urban population group showed: for body pain (52.21 ± 30.71 vs. 67.80 ± 25.28, p < 0.001); and for mental health (69.58 ± 18.98 vs. 64.60 ± 14.88, p < 0.006). Differences between groups were analysed using Student's t-test for independent samples, which showed statistical significance (p < 0.05). This research offers evidence that the rural population presents better levels of mental health and lower levels of bodily pain in the domains of the SF-36 Health Questionnaire comparing with the urban population.Departamento de Biología Ambiental y Salud Públic

Proanthocyanidin characterization and bioactivity of extracts from different parts of Uncaria tomentosa L. (cat’s claw)

This article belongs to the Special Issue Dietary Antioxidants and Health Promotion.-- et al.Apart from alkaloids, bioactive properties of Uncaria tomentosa L. have been attributed to its phenolic constituents. Although there are some reports concerning low-molecular-weight polyphenols in U. tomentosa, its polymeric phenolic composition has been scarcely studied. In this study, phenolic-rich extracts from leaves, stems, bark and wood (n = 14) of Uncaria tomentosa plants from several regions of Costa Rica were obtained and analysed in respect to their proanthocyanidin profile determined by a quadrupole-time-of-flight analyser (ESI-QTOF MS). Main structural characteristics found for U. tomentosa proanthocyanidins were: (a) monomer composition, including pure procyanidins (only composed of (epi)catechin units) and propelargonidins (only composed of (epi)afzelechin units) as well as mixed proanthocyanidins; and (b) degree of polymerization, from 3 up to 11 units. In addition, U. tomentosa phenolic extracts were found to exhibit reasonable antioxidant capacity (ORAC (Oxygen Radical Absorbance Capacity) values between 1.5 and 18.8 mmol TE/g) and antimicrobial activity against potential respiratory pathogens (minimum IC of 133 µg/mL). There were also found to be particularly cytotoxic to gastric adenocarcinoma AGS and colon adenocarcinoma SW620 cell lines. The results state the particularities of U. tomentosa proanthocyanidins and suggest the potential value of these extracts with prospective use as functional ingredients.This project was partially funded by grant from the Spanish International Development Cooperation Agency (AECID) (Ref. A/023397/09 and A/030037/10) and a joint grant from the Costa Rica-USA Foundation (CRUSA) and the Spanish Scientific Research Council (CSIC) (Ref. CR0024). Authors also thank financial support from the Comunidad de Madrid (Spain) and European funding from FEDER program (projects AVANSECAL-CM S2013/ABI-3028 and ALIBIRD-CM S2013/ABI-2728) and from the University of Costa Rica. Special thanks are due to Eng. Juan Jose Cordero from Costa Rican National Production Council (CNP).Peer Reviewe