180 research outputs found
Aerosoles formados por nanomateriales: Monitorización y evaluación de la exposición en entornos laborales
La Nanotecnología es un conocimiento clave para el desarrollo de futuras innovaciones y nuevos productos. A pesar de los innegables beneficios que pueden resultar de su desarrollo, existe una creciente preocupación entre la comunidad científica y algunos gobiernos por el riesgo para la salud que supone la presencia de materiales totalmente nuevos. En respuesta al creciente interés social en Nanoseguridad, la presente tesis ha pretendido avanzar en el conocimiento relacionado con las emisiones producidas durante la manipulación de distintos materiales nanopartículados y la monotorización y evaluación de la exposición en entornos laborales. Esta tesis doctoral está presentada como Compendio de 8 publicaciones con unidad temática
Hydrogenation of furfural over supported Pd catalysts
Lignocellulosic biomass is the most abundant and economical non-fossil carbon source. Furthermore, it is not competitive with the food chain, coming from lignocellulosic wastes including agricultural and food processing, local urban solid and forestry wastes. However, these are made up of complex carbohydrates (mainly, cellulose and hemicellulose), which require to be broken down in their respective monomers. The hemicellulose is mainly composed of pentosans, which, after an initial hydrolysis step, are dehydrated to furfural. Furfural is an important platform molecule, since it has a wide range of applications, being considered the main chemical, aside from bioethanol, obtained from the sugar platform for the synthesis of chemicals, for plastics, agrochemical and pharmaceutical industries.
In the present work, the hydrogenation of furfural in gas phase has been studied by using Pd as active phase, and different metal oxides as support, in order to elucidate the influence of the support on the catalytic performance. Furfural can be converted into chemicals with important applications in many different industrial fields. Thus, reduction of furfural can proceed through different pathways depending on the experimental conditions, where the nature of the catalysts plays a key role. In the case of Pd-based catalysts, the main products come from the decarbonylation of furfural.The catalytic results reveals that the nature of the support exerts an important influence on furfural conversion and yield. The highest conversion (92% after 5 h of TOS at 463 K) was attained with a Pd-SiO2 catalyst, with a furan yield of 70 mol%. This catalyst is the most selective to furan and a moderate deactivation is only observed after 5 h reaction. The catalytic performance demonstrates that decarbonylation reaction was the main pathway, although the formation of furfuryl alcohol and 2-methylfuran also suggests that the hydrogenation of the carbonyl group of furfural takes place.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tec
¿Qué comemos en la Escuela? Socialización y vida escolar en GuatemalaWhat do we eat at school? Socialization and the school life in Guatemala
El proyecto de investigación sobre el cual fue elaborado este artículo, se orientó a analizar cómo los procesos de socialización influyen en la vida escolar y situación nutricional de niñas y niños que asisten a tres escuelas públicas ubicadas en zonas distintas; ya que se identificó que estudios anteriores centraban su atención en la medición cuantitativa del fenómeno de la nutrición y la alimentación. Desde un enfoque sociológico se plantearon varias unidades de análisis como: la vida escolar de la que se determinó la influencia de la tienda escolar, la interacción social entre niñas y niños y el rol educativo de los maestros. Todas esas influencias recibidas modifican la situación nutricional de niñas y niños; para identificar estos cambios en el comportamiento se procedió a la construcción de una guía de observación, una guía de entrevista y de grupo focal. A partir de la aplicación de estas técnicas y del análisis de la información obtenida, se identificó que la educación alimentaria-nutricional en las escuelas visitadas es no planificada, poco frecuente, no incluye a los familiares y se limita a consejos ocasionales pues los escolares entrevistados respondieron que no se les impartían charlas o talleres sobre el tema; aunque en contraste algunos maestros afirmaron darlas, el proceso no es el adecuado por lo anteriormente descrito
Sobrecarga laboral y salud mental del personal del centro de Salud Turpo, Andahuaylas - Apurímac, 2022
El propósito del estudio es el de determinar como la la sobrecarga laboral se relaciona con la salud mental del personal del Centro de Salud Turpo, Andahuaylas - Apurímac 2022. Material y método: se aplicó el método hipotético deductivo con un diseño no experimental desarrollado en un corte transversal, con la participación de 85 personal del Centro de Salud Turpo, Andahuaylas - Apurímac 2022. La encuesta fue utilizada como técnica en la recolección de datos a través del uso de dos cuestionarios. Resultados: se pudo evidenciar que en la sobrecarga laboral baja se presenta una salud mental regular con un 2.4% y optima en un 11.8%. en el caso de la sobrecarga laboral media, el 27.1% presenta una salud mental regular el 23.5% optima, y cuando la sobrecarga es alta el 25.9% presenta una salud mental deficiente. Se concluye que la sobrecarga de trabajo se relaciona de manera inversa con la salud mental, con un coeficiente de correlación de -0.776 significante al 0.000
Oxidative Condensation of Furfural with Ethanol Using Pd-Based Catalysts: Influence of the Support
PdO nanoparticles were deposited on several supports (β-zeolite, Al2O3, Fe2O3, MgO, and SiO2), which displayed different crystallinity, textural properties, and amount of acid and basic sites. These catalysts were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), N2 adsorption–desorption isotherms at −196 °C, NH3 and CO2 thermoprogrammed desorption analyses (NH3- and CO2-TPD, and X-ray photoelectron spectroscopy (XPS). Pd-based catalysts were tested in the oxidative condensation of furfural with ethanol to obtain value-added chemicals. The catalytic results revealed high conversion values, although the presence of a high proportion of carbonaceous deposits, mainly in the case of the PdO supported on β-zeolite and Al2O3, is also noteworthy. The presence of basic sites led to a beneficial effect on the catalytic behavior, since the formation of carbonaceous deposits was minimized. Thus, the 2Pd-MgO (2 wt.% Pd) catalyst reached the highest yield of furan-2-acrolein (70%) after 3 h of reaction at 170 °C. This better catalytic performance can be explained by the high basicity of MgO, used as support, together with the large amount of available PdO, as inferred from XPS.The authors are grateful to financial support from the Spanish Ministry of Innovation, Science and Universities (Project RTI2018-094918-B-C44) and FEDER (European Union) funds, and University of Málaga (UMA18-FEDERJA-171)
La participación de alumnos en Comunidades de Aprendizaje
Nuestro objetivo es dar a conocer la actividad “Prácticas de Intervención Psicoeducativa en Comunidades de Aprendizaje” que ha sido ofrecida en el curso 2013-14 de manera interdepartamental, con la participación de profesores de los Departamentos de Psicología Evolutiva y de la Educación y de Didáctica y Organización Educativa, de la Universidad de Sevilla. Se propuso para todos los alumnos de la Universidad como actividad de libre configuración, de reconocimiento de créditos o de voluntariado para los que no optasen por ninguna de las dos posibilidades primeras.
La participación en Grupos Interactivos, Tertulias Dialógicas o en otras actividades llevadas a cabo por los estudiantes en los centros que forman parte de la Red de Comunidades de Aprendizaje de Sevilla está siendo gratificante personalmente para ellos y muy productiva desde un punto de vista académico para implicar a los estudiantes en actuaciones educativas de éxito y de superación del fracaso escolar.Our aim is to publicize the internships “Intervention in Educational Learning Communities” that has been offered in the academic year 2013-2014 with the participation of professors from the Departments of Psychology and Education and Teaching and Educational Organization, University of Seville. It has been offered to all university students and they will earn free-elected credits, recognition of credits or, at least, volunteerism for those who do not select the previous two options.
The collaboration in Interactive Groups, Discussion Groups or other activities developed by the students in schools that are taken part in the Learning Community Network of Seville has being personally rewarded for them and really productive from the academic perspective. With this programme, students have been involved in successful practical experiences, overcoming school failure
Shift Work and Prostate Cancer: An Updated Systematic Review and Meta-Analysis
The International Agency of Research in Cancer (IARC) has recently confirmed shift work as
a type 2A carcinogen. The results presented in published epidemiological studies regarding prostate
cancer are inconsistent and the association remains controversial. The aims of this study were: (a) to
investigate the possible association between shift work and prostate cancer incidence, identifying
possible sources of heterogeneity; and (b) to analyze the potential effect of publication bias. A search
for cohort and case-control studies published from January 1980 to November 2019 was conducted.
The quality of the articles was assessed using the Newcastle–Ottawa Scale. Pooled OR were calculated
using random-effects models. Heterogeneity was evaluated using Cochran’s Q test and data were
stratified by potential sources of heterogeneity. Publication bias was analyzed. Eighteen studies
were included. No association was found between rotating/night-shift work and prostate cancer,
pooled OR 1.07 (95%CI 0.99 to 1.15), I2 = 45.7%, p = 0.016. Heterogeneity was eliminated when only
cohort studies (pooled OR 1.03; 95%CI 0.96 to 1.10; I2 = 18.9%, p = 0.264) or high-quality studies
(pooled OR 0.99; 95%CI 0.89 to 1.08; I2 = 0.0%, p = 0.571) were considered. A publication bias was
detected. An association between shift work and prostate cancer cannot be confirmed with the
available current data. Future analytical studies assessing more objective homogeneous exposure
variables still seem necessary
Obesity as a Risk Factor for Prostate Cancer Mortality: A Systematic Review and Dose-Response Meta-Analysis of 280,199 Patients
Khalid Saeed Khan is a Distinguished Investigator funded by the Beatriz Galindo (senior modality) Program grant given to the University of Granada by the Ministry of Science, Innovation, and Universities of the Spanish Government.Simple Summary Results from individual studies on the association between obesity and prostate cancer mortality remain inconclusive; additionally, several large cohort studies have recently been conducted. We aimed to systematically review all available evidence and synthetize it using meta-analytic techniques. The results of our study showed that obesity was associated with prostate cancer specific mortality and all-cause mortality. The temporal association was consistent with a dose-response relationship. Our results demonstrated that obesity, a potentially modifiable prognostic factor, was associated with higher prostate cancer mortality. This study improved the evidence regarding the potential impact of lifestyle on improving prostate cancer prognosis. Strategies aimed at maintaining normal, or reducing abnormal, body mass index in diagnosed prostate cancer patients might improve survival. These results should guide urologists, oncologists, patients, policy-makers and primary care providers with respect to evidence-based practice and counselling concerning lifestyle changes after prostate cancer diagnosis.The aim of this study was to systematically review all evidence evaluating obesity as a prognostic factor for PC mortality. Cohort and case-control studies reporting mortality among PC patients stratified by body mass index (BMI) were included. The risk of mortality among obese patients (BMI >= 30) was compared with the risk for normal weight (BMI = 8), obesity was associated with increased PC-specific mortality (HR: 1.24, 95% CI: 1.14-1.35, I-2: 0.0%) and maintained the dose-response relationship (HR: 1.11 per 5 kg/m(2) increase in BMI, 95% CI: 1.07-1.15, I-2: 26.6%). Obesity had a moderate, consistent, temporal, and dose-response association with PC mortality. Weight control programs may have a role in improving PC survival.Ministry of Science, Innovation, and Universities of the Spanish Governmen
Long-term nightshift work and breast cancer risk: An updated systematic review and meta-analysis with special attention to menopausal status and to recent nightshift work
This systematic review discusses long-term NSW and female BC risk, with special attention to differences between pre-and postmenopausal BC, to test the association with recent NSW. The review follows PRISMA guidelines (Prospero registry: CRD42018102515). We searched PubMed, Embase, and WOS for case–control, nested case–control, and cohort studies addressing long-term NSW (≥15 years) as risk exposure and female BC as outcome until 31 December 2020. Risk of bias was evaluated with the Newcastle–Ottawa scale. Eighteen studies were finally in-cluded (eight cohorts; five nested case–control; five case–control). We performed meta-analyses on long-term NSW and BC risk; overall and by menopausal status; a subanalysis on recent long-term NSW, based on studies involving predominantly women below retirement age; and a dose– response meta-analysis on NSW duration. The pooled estimate for long-term NSW and BC was 1.13 (95%CI = 1.01–1.27; 18 studies, I2 = 56.8%, p = 0.002). BC risk increased 4.7% per 10 years of NSW (95%CI = 0.94–1.09; 16 studies, I2 = 33.4%, p = 0.008). The pooled estimate for premenopausal BC was 1.27 (95%CI = 0.96–1.68; six studies, I2 = 32.0%, p = 0.196) and for postmenopausal BC 1.05 (95%CI = 0.90–1.24, I2 = 52.4%; seven studies, p = 0.050). For recent long-term exposure, the pooled estimate was 1.23 (95%CI = 1.06–1.42; 15 studies; I2 = 48.4%, p = 0.018). Our results indicate that long-term NSW increases the risk for BC and that menopausal status and time since exposure might be relevant.This research received no external funding
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