Au-Cu/SBA(Ti) based catalysts for photocatalytic applications

Comunicación a congresoIn this work, it has been synthesized several Au and Au-Cu alloy photocatalysts supported on two different mesoporous supports: a non-commercial SBA-15 and a post-synthesis TiO2 modified SBA-15 (TiSBA-15), with which a high dispersion of TiO2 species have been achieved maintaining the SBA-15 structure. In addition, it has also been obtained highly dispersed Au nanoparticles confined in SBA-15 pore channels, as can be observed in Figure 1. The photocatalysts have been preliminary tested in the preferential CO oxidation in a H2-rich stream (CO-PROX) at room temperature and atmospheric pressure under simulated solar light irradiation. In spite of the very low gold and copper loading (1.5 wt% and 0.5wt% respectively), the catalysts resulted active and selective in the low temperature photo-CO-PROX.Universidad de Málaga, Campus de Excelencia Internacional Andalucía Tec

Synthesis of type A zeolites from natural kaolinite for their application in CO2 capture processes

Climate change is the greatest environmental threat of the 21st century, with major economic, social and environmental consequences. The level of carbon dioxide (CO2) emissions has increased by 31%, therefore, both governments and the scientific community are taking steps to mitigate emissions into the atmosphere. The most economically sustainable method is the use of low cost adsorbents that perform a selective adsorption of CO2 with respect to other inert gases such as N2. Clay minerals are highly available materials on the planet, are a low cost raw material and have great versatility for various processes in the field of adsorption and catalysis. The present work describes the synthesis of type A zeolite from a hydrothermal process in basic medium using metacaolinite as a starting material. Several parameters such as temperature and time were modified to evaluate the relationship between the formation conditions of the zeolite and its CO2 adsorption capacity. Synthesized catalysts were characterized by X-ray diffraction (XRD), N2 adsorption-desorption at -196 ºC, nuclear magnetic resonance of solids (NMR) and infrared spectroscopy (IR). In addition, the absorption capacity of CO2 with type A zeolites has been evaluated, and all the results were compared with the commercial zeolites. With respect to the results obtained, it can be said that the bands obtained by IR for the synthesized Zeolites are similar to those of the commercial Zeolite. On the other hand, the NMR results show that the synthesized and commercial zeolite present the same chemical environment. Finally, the textural parameters corroborate that in all cases the surface area is low from 12 m2g-1 for kaolinite to 7 m2g-1 for commercial zeolite AUniversidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

Metabolomic Effects of CeO₂, SiO₂ and CuO Metal Oxide Nanomaterials on HepG2 Cells

Background: To better assess potential hepatotoxicity of nanomaterials, human liver HepG2 cells were exposed for 3 days to five different CeO2 (either 30 or 100 μg/ml), 3 SiO2 based (30 μg/ml) or 1 CuO (3 μg/ml) nanomaterials with dry primary particle sizes ranging from 15 to 213 nm. Metabolomic assessment of exposed cells was then performed using four mass spectroscopy dependent platforms (LC and GC), finding 344 biochemicals. Results: Four CeO2, 1 SiO2 and 1 CuO nanomaterials increased hepatocyte concentrations of many lipids, particularly free fatty acids and monoacylglycerols but only CuO elevated lysolipids and sphingolipids. In respect to structure-activity, we now know that five out of six tested CeO2, and both SiO2 and CuO, but zero out of four TiO2 nanomaterials have caused this elevated lipids effect in HepG2 cells. Observed decreases in UDP-glucuronate (by CeO2) and S-adenosylmethionine (by CeO2 and CuO) and increased S-adenosylhomocysteine (by CuO and some CeO2) suggest that a nanomaterial exposure increases transmethylation reactions and depletes hepatic methylation and glucuronidation capacity. Our metabolomics data suggests increased free radical attack on nucleotides. There was a clear pattern of nanomaterial-induced decreased nucleotide concentrations coupled with increased concentrations of nucleic acid degradation products. Purine and pyrimidine alterations included concentration increases for hypoxanthine, xanthine, allantoin, urate, inosine, adenosine 3\u27,5\u27-diphosphate, cytidine and thymidine while decreases were seen for uridine 5\u27-diphosphate, UDP-glucuronate, uridine 5\u27-monophosphate, adenosine 5\u27-diphosphate, adenosine 5\u27-monophophate, cytidine 5\u27-monophosphate and cytidine 3\u27-monophosphate. Observed depletions of both 6-phosphogluconate, NADPH and NADH (all by CeO2) suggest that the HepG2 cells may be deficient in reducing equivalents and thus in a state of oxidative stress. Conclusions: Metal oxide nanomaterial exposure may compromise the methylation, glucuronidation and reduced glutathione conjugation systems; thus Phase II conjugational capacity of hepatocytes may be decreased. This metabolomics study of the effects of nine different nanomaterials has not only confirmed some observations of the prior 2014 study (lipid elevations caused by one CeO2 nanomaterial) but also found some entirely new effects (both SiO2 and CuO nanomaterials also increased the concentrations of several lipid classes, nanomaterial induced decreases in S-adenosylmethionine, UDP-glucuronate, dipeptides, 6-phosphogluconate, NADPH and NADH)

Repeated dietary exposure to low levels of domoic acid and problems with everyday memory: Research to public health outreach

Domoic Acid (DA) is a marine-based neurotoxin. Dietary exposure to high levels of DA via shellfish consumption has been associated with Amnesic Shellfish Poisoning, with milder memory decrements found in Native Americans (NAs) with repetitive, lower level exposures. Despite its importance for protective action, the clinical relevance of these milder memory problems remains unknown. The purpose of this study was to determine whether repeated, lower-level exposures to DA impact everyday memory (EM), i.e., the frequency of memory failures in everyday life. A cross-sectional sample of 60 NA men and women from the Pacific NW was studied with measures of dietary exposure to DA via razor clam (RC) consumption and EM. Findings indicated an association between problems with EM and elevated consumption of RCs with low levels of DA throughout the previous week and past year after controlling for age, sex, and education. NAs who eat a lot of RCs with presumably safe levels of DA are at risk for clinically significant memory problems. Public health outreach to minimize repetitive exposures are now in place and were facilitated by the use of community-based participatory research methods, with active involvement of state regulatory agencies, tribe leaders, and local physicians

Nanoestructuras de ceria-titania para fotodegradar azul de metileno con luz solar simulada

En los últimos años la protección ambiental y el uso de fuentes de energía renovables son dos objetivos principales en la investigación química. La energía solar se puede aprovechar para la degradación fotocatalítica de moléculas orgánicas contaminantes, hormonas o medicamentos, tanto en el aire, en el agua, como en las superficies, porque la luz solar es capaz de descomponerlas [1]. A pesar de la gran cantidad de aplicaciones fotocatalíticas de la titania (TiO2), fotocatalizador no tóxico, de bajo costo y muy prometedor [2], hay algunos factores críticos que limitan su fotoactividad. El principal es el valor de su salto de energía, que limita su uso como fotocatalizador en la región UV del espectro. Con el objetivo principal de extender su uso a la región visible del espectro, en literatura se ha propuesto el depósito de metales nobles en su superficie, modificaciones superficiales, así como el dopaje con iones de metales de transición o elementos de tierras raras. En este sentido, el uso de ceria (CeO2) ha atraído una gran atención debido a propiedades como su biocompatibilidad, inercia química así como su actividad en reacciones de oxidación, relacionada con la formación vacantes de oxígeno en su superficie [3]. Se ha comprobado que el sistema oxídico mixto CeO2-TiO2 es más fotoactivo que la titania pura debido a la disminución del salto de energía y a la mejora en la movilidad de los excitones. Este trabajo tiene como objetivo desarrollar fotocatalizadores basados en nanoestructuras de titania que sean activas en el visible, dopando la matriz de titania con cerio. Principalmente se pretende evaluar tanto el papel del cerio como la morfología del nanomaterial en la respuesta fotocatalítica bajo luz UV y solar.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

The HIV/AIDS Epidemic in Miami: Perspectives of Stakeholders and Frontline Providers

Background: Miami, Florida persists as an epicenter of HIV/AIDS nationally and has been more delayed than other areas with high HIV burden in implementing public health measures that mitigate transmission risk. These issues among other social and structural-level determinants have complicated progress in addressing HIV/AIDS in Miami. Purpose: The stagnated progress in improving HIV outcomes in Miami necessitated a more comprehensive understanding of the experiences and insights of stakeholders within the system. We used a stakeholder analysis approach to understand the complexity of driving factors and key challenges facing this HIV epidemic. Methods: A stakeholder analysis was conducted through 11 focus groups (64 participants) with front line workers working in non-profit, community-based agencies in Miami. The interview guide was designed to elicit a broad discussion on the social and intermediary determinants of HIV/AIDS, as well as the context surrounding barriers to treatment. Data were analyzed using qualitative software for thematic analysis. Results: Participants highlighted particular populations vulnerable to HIV/AIDS and insufficiently engaged in treatment, including immigrants and people who use drugs. Stigma surrounding HIV/AIDS as well as sexual orientation, mental health, and drug use was a noted persisting barrier. Participants expressed needs for more targeted outreach and education for both prevention and treatment. Numerous systemic gaps were identified as barriers to treatment engagement and retention. Other comorbidities and socioeconomic challenges, including criminal justice histories, housing instability and low educational attainment, also hamper HIV/AIDS management. Discussion: Through these discussions with stakeholders representing a diversity of voices, findings can inform comprehensive and coordinated strategies for curbing the HIV/AIDS epidemic in Miami. The development of prevention and treatment interventions should consider cultural contexts of health behaviors, multi-level stigma related to HIV/AIDS and other comorbid and socioeconomic challenges, and increased implementation of harm reduction programs such as PrEP delivery and syringe exchange programs

Satellites and central galaxies in SDSS: The influence of interactions on their properties

We use SDSS-DR14 to construct a sample of galaxy systems consisting of a central object and two satellites. We adopt projected distance and radial velocity difference criteria and impose an isolation criterion to avoid membership in larger structures. We also classify the interaction between the members of each system through a visual inspection of galaxy images, finding ${sim}80{{ m per cent}}$ of the systems lack evidence of interactions whilst the remaining ${sim}20{{ m per cent}}$ involve some kind of interaction, as inferred from their observed distorted morphology. We have considered separately, samples of satellites and central galaxies, and each of these samples were tested against suitable control sets to analyse the results. We find that central galaxies showing signs of interactions present evidence of enhanced star formation activity and younger stellar populations. As a counterpart, satellite samples show these galaxies presenting older stellar populations with a lower star formation rate than the control sample. The observed trends correlate with the stellar mass content of the galaxies and with the projected distance between the members involved in the interaction. The most massive systems are less affected since they show no star formation excess, possibly due to their more evolved stage and less gas available to form new stars. Our results suggest that it is arguably a transfer of material during interactions, with satellites acting as donors to the central galaxy. As a consequence of the interactions, satellite stellar population ages rapidly and new bursts of star formation may frequently occur in the central galaxy.Fil: Mesa, Valeria Alejandra. Universidad de La Serena; Chile. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales. Provincia de Mendoza. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales. Universidad Nacional de Cuyo. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales; ArgentinaFil: Alonso, Sol. Universidad Nacional de San Juan. Facultad de Ciencias Exactas, Físicas y Naturales. Departamento de Geofísica y Astronomía; ArgentinaFil: Coldwell Lloveras, Georgina Vanesa. Universidad Nacional de San Juan. Facultad de Ciencias Exactas, Físicas y Naturales. Departamento de Geofísica y Astronomía; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Juan; ArgentinaFil: Garcia Lambas, Diego Rodolfo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Astronomía Teórica y Experimental. Universidad Nacional de Córdoba. Observatorio Astronómico de Córdoba. Instituto de Astronomía Teórica y Experimental; ArgentinaFil: Nilo Castellon, J. L. Universidad de La Serena; Chil

The Carnegie Supernova Project I: photometry data release of low-redshift stripped-envelope supernovae

The first phase of the Carnegie Supernova Project (CSP-I) was a dedicated supernova follow-up program based at the Las Campanas Observatory that collected science data of young, low-redshift supernovae between 2004 and 2009. Presented in this paper is the CSP-I photometric data release of low-redshift stripped-envelope core-collapse supernovae. The data consist of optical (uBgVri) photometry of 34 objects, with a subset of 26 having near-infrared (YJH) photometry. Twenty objects have optical pre-maximum coverage with a subset of 12 beginning at least five days prior to the epoch of B-band maximum brightness. In the near-infrared, 17 objects have pre-maximum observations with a subset of 14 beginning at least five days prior to the epoch of J-band maximum brightness. Analysis of this photometric data release is presented in companion papers focusing on techniques to estimate host-galaxy extinction (Stritzinger et al., submitted) and the light-curve and progenitor star properties of the sample (Taddia et al., submitted). The analysis of an accompanying visual-wavelength spectroscopy sample of ~150 spectra will be the subject of a future paper.Comment: Updated a couple of small error

Autonomous underwater gliders monitoring variability at "choke points" in our ocean system: a case study in Western Mediterranean Sea

Publicado

Analysis of candidates for interacting galaxy clusters: I. A1204 and A2029/A2033

Merging galaxy clusters allow for the study of different mass components, dark and baryonic, separately. Also, their occurrence enables to test the ΛCDM scenario, which can be used to put constraints on the selfinteracting cross-section of the dark-matter particle. It is necessary to perform a homogeneous analysis of these systems. Hence, based on a recently presented sample of candidates for interacting galaxy clusters, we present the analysis of two of these cataloged systems. In this work, the first of a series devoted to characterizing galaxy clusters in merger processes, we perform a weak lensing analysis of clusters A1204 and A2029/2033 to derive the total masses of each identified interacting structure together with a dynamical study based on a two-body model. We also describe the gas and the mass distributions in the field through a lensing and an X-ray analysis. This is the first of a series of works which will analyze these type of system in order to characterize them. Neither merging cluster candidate shows evidence of having had a recent merger event. Nevertheless, there is dynamicalevidence that these systems could be interacting or could interact in the future. It is necessary to include more constraints in order to improve the methodology of classifying merging galaxy clusters.Characterization of these clusters is important in order to properly understand the nature of these systems and their connection withdynamical studies.Fil: Gonzalez, Elizabeth Johana. Universidad Nacional de Córdoba. Observatorio Astronómico de Córdoba; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Astronomía Teórica y Experimental. Universidad Nacional de Córdoba. Observatorio Astronómico de Córdoba. Instituto de Astronomía Teórica y Experimental; ArgentinaFil: de Los Rios, Martín Emilio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Astronomía Teórica y Experimental. Universidad Nacional de Córdoba. Observatorio Astronómico de Córdoba. Instituto de Astronomía Teórica y Experimental; ArgentinaFil: Oio, Gabriel Andrés. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Astronomía Teórica y Experimental. Universidad Nacional de Córdoba. Observatorio Astronómico de Córdoba. Instituto de Astronomía Teórica y Experimental; ArgentinaFil: Hernández Lang, Daniel. Universidad de La Serena; ChileFil: AguirreTagliaferro, Tania. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Astronomía Teórica y Experimental. Universidad Nacional de Córdoba. Observatorio Astronómico de Córdoba. Instituto de Astronomía Teórica y Experimental; ArgentinaFil: Dominguez Romero, Mariano Javier de Leon. Universidad Nacional de Córdoba. Observatorio Astronómico de Córdoba; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Astronomía Teórica y Experimental. Universidad Nacional de Córdoba. Observatorio Astronómico de Córdoba. Instituto de Astronomía Teórica y Experimental; ArgentinaFil: Nilo Castellon, Jose Luis Emilio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Astronomía Teórica y Experimental. Universidad Nacional de Córdoba. Observatorio Astronómico de Córdoba. Instituto de Astronomía Teórica y Experimental; Argentina. Universidad de la Serena; ChileFil: Cuevas L., H.. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Astronomía Teórica y Experimental. Universidad Nacional de Córdoba. Observatorio Astronómico de Córdoba. Instituto de Astronomía Teórica y Experimental; ArgentinaFil: Valotto, Carlos Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Astronomía Teórica y Experimental. Universidad Nacional de Córdoba. Observatorio Astronómico de Córdoba. Instituto de Astronomía Teórica y Experimental; Argentina. Universidad Nacional de Córdoba. Observatorio Astronómico de Córdoba; Argentin