99 research outputs found

    Carbon Materials as Additives to WO3 for an Enhanced Conversion of Simulated Solar Light

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    We have explored the impact of the incorporation of nanoporous carbons as additives to tungsten oxide on the photocatalytic degradation of two recalcitrant pollutants: rhodamine B (RhB) and phenol, under simulated solar light. For this purpose, WO3/carbon mixtures were prepared using three carbon materials with different properties (in terms of porosity, structural order and surface chemistry). Despite the low carbon content used (2 wt.%), a significant increase in the photocatalytic performance of the semiconductor was observed for all the catalysts. Moreover, the influence of the carbon additive on the performance of the photocatalysts was found to be very different for the two pollutants. Carbon additives of hydrophobic nature increased the photodegradation yield of phenol compared to bare WO3, likely due to the higher affinity and stronger interactions of phenol molecules toward basic nanoporous carbons. Oppositely, the use of acidic carbon additives led to higher RhB conversions due to increased acidity of the WO3/carbon mixtures and the stronger affinity of the pollutant for acidic catalyst’s surfaces. As a result, the photooxidation of RhB is favored by means of a coupled (photosensitized and photocatalytic) degradation mechanism. All these results highlight the importance of favoring the interactions of the pollutant with the catalyst’s surface through a detailed design of the features of the photocatalyst.The authors thank the financial support of the Spanish MINECO (grant CTM2014/56770-R). RC thanks PCTI Asturias for her PhD (BP1231, fondos FEDER) fellowship.Peer reviewe

    Boosting the visible-light photoactivity of Bi2WO6 using acidic carbon additives

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    We have explored the role of the physicohemical properties of carbon materials as additives to bismuth tungstate on its structure, optical properties, and photocatalytic activity for the degradation of rhodamine B under visible light. For this purpose, C/Bi2WO6 hybrid composites were prepared following two different routes: (i) physical mixture of the catalyst components, and (ii) one-pot hydrothermal synthesis of the semiconductor in the presence of the carbon additive. Three carbons with different properties were selected as additives: biomass-derived activated carbon, carbon nanotubes and carbon spheres obtained from polysaccharides. Data has shown the outstanding role of the acidic/basic nature of the carbon additive, and of the synthetic method on the photocatalytic performance of the resulting composites. For a given additive, the degradation rate of RhB is greatly improved for the catalysts prepared through a one-step hydrothermal synthesis, where there is low shielding effect of the carbon matrix. Carbon additives of acidic nature boost the surface acidity of the hybrid photocatalyst, thereby enhancing the photodegradation of RhB under visible light via a coupled mechanism (photosensitization, semiconductor photocatalysis and carbon-photon mediated reactions).The authors thank the financial support of MINECO (grants CTM2011/23378 and CTQ2011/26617) and PCTI Asturias (Fondos Feder 2007-2013, grant PC10-002). RJC thanks PCTI Asturias for her Severo Ochoa fellowshipPeer reviewe

    Effect of the irradiation wavelength on the performance of nanoporous carbon as an additive to TiO2

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    We report the dependence of the photochemical activity of titania/carbon hybrid catalysts toward the degradation of phenol from solution using polychromatic light and filters. In all cases larger photooxidative efficiencies were obtained using light at 200 nm 200 nm. The photocatalytic runs carried out with the nonporous carbon alone confirmed a certain level of intrinsic photoactivity under both irradiation conditions. Nevertheless, a clear deactivation was evident after 60 min of irradiation suggesting that the photoactive sites in the carbon are either consumed or deactivated in the course of the reaction. The composition of the catalyst and the illumination conditions also have a strong effect on the nature of the degradation intermediates, with a marked regioselectivity toward ortho-substitution at high energy photons and when the carbon component is added to the catalyst composition.The authors thank Cordex (Portugal) for kindly supplying sisal. The financial support of the pluriannual funding to CQB (UID/MULTI/00612/2013), and MINECO (CTM2014/56770-R, AIB2010-PT00209) is also acknowledged. MAA and ASM thank FCT for their PhD (SFRH/BD/71673/2010) and Post-Doc (SFRH/BPD/86693/2012) fellowships, respectively. RJC thanks PCTI Asturias Fondos Feder for her Severo Ochoa fellowship. The authors thank Dr. Matos for fruitful discussion.Peer reviewe

    In Vitro Toxicity of Asparagus Saponins in Distinct Multidrug-Resistant Colon Cancer Cells

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    Colorectal cancer is the third most common cancer in the world. Many efforts have focused on finding natural molecules with potential chemo-preventive activity due to their low toxicity compared to synthetic drugs. However, comprehensive information on the bioactive fractions and components is still missing. In this study, we developed a method for the quantitative separation and isolation of saponins from asparagus genotypes consisting of an adsorption chromatography and subsequent liquid chromatographic separation on a reversed-phase column. The saponins isolated were tested for their cytotoxic activity against human colon cancer cell lines, which could develop cross-resistance to a wide variety of chemotherapeutic drugs. Our results showed that Huétor-Tájar asparagus saponins (HTSAP), mainly protodioscin and HTSAP-10 have higher cytotoxic activity than HTSAP-1, HTSAP-6, and HTSAP-8. This study links the potential anticancer effect of asparagus to specific saponins and unveils the triguero Huétor-Tájar asparagus as a nutraceutical particularly in colon cancer therapiesMinisterio de Economía y Competitividad JCI-2012-1308

    Visible light driven photooxidation of phenol on TiO2/Cu-loaded carbon catalysts

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    The photocatalytic performance of titania/Cu-carbon composites was investigated towards phenol degradation under visible light. The approach consisted on the incorporation of the transition metal on the carbon component of the hybrid composite via impregnation of the carbon precursor with a metal salt followed by activation. Data showed a homogeneous dispersion of copper particles within the carbonaceous matrix, predominantly as copper (II) species. The synthesized carbons displayed a well developed nanoporous texture, although comparatively the impregnation of copper caused a marked inhibition of the textural development of the carbon precursor. The phenol photooxidation tests carried out on 1:1 titania/carbon composites showed the outstanding role of copper under visible light, with an increased efficiency in terms of phenol conversion, mineralization degree and degradation rate. This is important, since similar overall conversions were obtained with half of the amount of the photoactive semiconductor (1:1 composites). The beneficial effect of copper loading was also observed in the marked regioselectivity towards the preferential formation of catechol. Furthermore, the copper-loaded photocatalyst was found to be stable with no lixiviation or photorreduction of the copper species after illumination.The authors thank Cordex (Portugal) for kindly supplying sisal. The financial support of the pluriannual funding to CQB (PEst-OE/QUI/UI0612/2013), MINECO (CTM2008/01956, CTM2011/23378, AIB2010-PT00209) and PCTI Asturias (Fondos Feder 2007-2013, grant PC10-002) is also acknowledged. MAA and ASM thank FCT for their PhD (SFRH/BD/71673/2010) and postdoc (SFRH/BPD/86693/2012) fellowships, respectively. RJC thanks PCTI Asturias for her Severo Ochoa fellowship.Peer reviewe

    Aldehyde Dehydrogenase 3 Is an Expanded Gene Family with Potential Adaptive Roles in Chickpea

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    Legumes play an important role in ensuring food security, improving nutrition and enhancing ecosystem resilience. Chickpea is a globally important grain legume adapted to semi-arid regions under rain-fed conditions. A growing body of research shows that aldehyde dehydrogenases (ALDHs) represent a gene class with promising potential for plant adaptation improvement. Aldehyde dehydrogenases constitute a superfamily of proteins with important functions as ‘aldehyde scavengers’ by detoxifying aldehydes molecules, and thus play important roles in stress responses. We performed a comprehensive study of the ALDH superfamily in the chickpea genome and identified 27 unique ALDH loci. Most chickpea ALDHs originated from duplication events and the ALDH3 gene family was noticeably expanded. Based on the physical locations of genes and sequence similarities, our results suggest that segmental duplication is a major driving force in the expansion of the ALDH family. Supported by expression data, the findings of this study offer new potential target genes for improving stress tolerance in chickpea that will be useful for breeding programs

    Saponins from edible spears of wild asparagus inhibit AKT, p70S6K, and ERK signalling, and induce apoptosis through G0/G1 cell cycle arrest in human colon cancer HCT-116 cells

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    41 Páginas, 6 Figuras, 1 TablaThe effects of steroidal saponins from edible spears of wild triguero Huetor-Tajar asparagus on some of the oncogenic molecular pathways that are affected in human colon cancer cells were investigated. Reverse-phase chromatography and a new HPLC-MS method were used to respectively isolate and analyse the composition of the steroidal saponins. They were resistant to simulated digestion and, when in contact with HTC-116 human colon carcinoma cells, interfered with extracellular signal-regulated kinase (ERK), S6 kinase (p70S6K, mTOR), and RAC-alpha serine/threonine-protein kinase (AKT) pathways by a downregulation of these proteins. The expressions of cyclins D, E, and A were also decreased, leading to G0/G1 cell cycle arrest. In addition, these steroidal saponins induced typical features of apoptosis by the promotion of caspase-3 activity, poly(ADP-ribose) polymerase 1 (PARP-1) cleavage, and DNA fragmentation. These results offer potential dietary intervention strategy against human colon cancer cells.This study was supported by grants AGL2011-29632 and AGL2011-29008 funded by MICINN. S.L. acknowledges financial support from the Spanish MINECO (JCI-2012-13084, Juan de la Cierva) and the Spanish Research Council (CSIC)/JAE-doc Program (JAEDOC089), a contract cofounded by the European Social Fund (ESF).Peer reviewe

    Gender and Leadership Positions in Spanish Dentistry

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    The Research Ethics Committee of the University of Granada issued a favorable report in relation to the present research under number 2430/CEIH/2021.Data Availability The data that support the findings of this study are available from the corresponding author upon request.Dentists in Spain reached equal gender representation in 2012 and the number of female dentists has continued to grow (until 57.3% in 2020). This study aims to increase evidence about the gender distribution on the high responsibility positions and opinion leaders of the dental profession and academia. Composition of the executive comities of the main dental institutions of Spain (regional professional associations, national dental association, and scientific societies), members of the Faculty of Dentistry of the University of Granada in 2020 and speakers of the main dental congresses of 2019 (due to the lack of congress in 2020) were recorded and analyzed by genders using chi-squared test (P < .05). Mean representation of female dentists in executive committees of professional associations was 35.6%. More than 70% of presidents and vice-presidents of professional colleges and more than 60% of these positions in scientific societies were occupied by male dentists. None of dental congresses of 2019 reached equal gender participation, being 81.3% of lecturers presenting on main auditoriums male dentists. Although dental workforce in Spain is slightly overrepresented by females, leadership positions and figures among Spanish dentists doesn’t seem to reflect the gender distribution of the collective. There is a lack of women occupying highlevel positions in dentistry that proves the existence of the so-called “glass ceiling effect” on the profession. Further studies about sociodemographic aspects of dental workforce are needed to develop evidence-based policies for the collective.Research Projects of the Vice-rectorate of Equality, Inclusion and Sustainability of the University of Granada [grant number INV-IGU113-2020

    Spatial variability in threshold temperatures of heat wave mortality: impact assessment on prevention plans

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    Spain’s current heat wave prevention plans are activated according to administrative areas. This study analyses the determination of threshold temperatures for triggering prevention-plan activation by reference to isoclimatic areas, and describes the public health benefits. We subdivided the study area – the Madrid Autonomous Region (MAR) – into three, distinct, isoclimatic areas: ‘North’, ‘Central’ and ‘South’, and grouped daily natural-cause mortality (ICD-10: A00-R99) in towns of over 10,000 inhabitants (2000–2009 period) accordingly. Using these three areas rather than the MAR as a whole would have resulted in a possible decrease in mortality of 73 persons (38– 108) in the North area, and in aborting unnecessary activation of the plan 153 times in the Central area and 417 times in the South area. Our results indicate that extrapolating this methodology would bring benefits associated with a reduction in attributable mortality and improved effectiveness of public health interventions.This study was funded by a ‘Miguel Servet type 1’ grant (SEPY 1037/14), as well as a Health Research Fund grant (Fondo de Investigaciones Sanitarias/FIS Project ENPY1133/16 from the Carlos III Institute of Health

    Differences in mobility, driving styles and road crashes among drivers, according to their status of user and non-user of bicycle

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    Introducción: Se conoce la tendencia al menor respeto de las normas de seguridad vial por parte de los usuarios de bicicleta. Los objetivos de este estudio fueron identificar las diferencias en la movilidad, estilos de conducción y accidentalidad entre conductores de turismo, en función de su condición o no de usuarios de bicicleta y valorar el efecto de montar en bicicleta sobre cada una de estas variables. Material y Métodos: Se realizó un estudio transversal sobre una muestra de 1114 conductores de turismo (34,4% de ellos usuarios de bicicleta) empleando un cuestionario autoadministrado que valoró: su movilidad, uso de dispositivos de seguridad, estilos de conducción y accidentalidad. Resultados: Los conductores usuarios de bicicleta presentaron mayores exposiciones, manifestaron conducir más deprisa, se percibieron como mejores al volante y se implicaron más frecuentemente en estilos de conducción de riesgo. Conclusión: En nuestra población, ser usuario de bicicleta se asoció positivamente con todos los factores relacionados con una mayor morbi-mortalidad por tráfico.Introduction: It is well known the lower respect to the road safety rules by the bicycle users. The objectives of this study were to identify differences in mobility, driving styles and road crashes among car drivers, according to their condition or not as bicycle users and to assess the effect of being bicycle users on each of these variables. Material and Methods: A cross sectional study was conducted on a sample of 1114 car drivers (34.4% of them cyclists) using a self-administered questionnaire which assessed: mobility, use of safety devices, driving styles and road crashes. Results: The drivers who were also bicycle users had: higher level of exposure, they drove faster, they perceived themselves as better car drivers and they had been more frequently involved in risky-driving styles than car drivers not bicycle users. Conclusion: In our population, the bicycle user condition was positively associated with all factors that increase morbidity and mortality due to traffic accident
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