Search

Zinc oxide-hydroxyapatite composites were prepared using wet impregnation method. Firstly, a natural phosphate ore rich in silica and calcium phosphate was sieved to separate silica phase from phosphate phase. Then, through a chemical precipitation method, a pure hydroxyapatite (HAP) was obtained, which was used as a support for ZnO immobilization and applied for the photodegradation of two toxic contaminants: a transparent molecule (caffeine) and dye molecule (rhodamine B). During the present work two weight ratio percentages of zinc oxide were used: 25 wt.% and 50 wt.% of ZnO relative to HAP. The samples were characterized by X-ray diffraction (XRD), Fourier Transform Infrared (FTIR), X-ray Fluorescence (XRF), BET surface area (SBET), Scanning Electron Microscopy (SEM-EDS) and by Transmission Electron Microscopy (TEM-STEM). The immobilization of ZnO on HAP surface followed by thermal treatment at 400 °C for 2 h to get a homogenous dispersion of ZnO on the hydroxyapatite support. At high ZnO impregnation percentage, photodegradation performances of ZnO-HAP under UV illumination were fast and superior than the ZnO photocatalyst alone. The results showed that due to the presence of HAP, the conversion of both molecules became faster and greater, since it promotes the synergic phenomena of adsorption and photocatalysis. The toxicity of the treated substrate solutions obtained in the corn kernels germination test indicated a low toxicity after the photodegradation processes, probably due to a high mineralization degree.

In this study, platinized mixed oxides (TiO2–Nb2O5) were tested on photocatalytic hydrogen production from a glycerol solution under UV light. Different samples with different Ti:Nb ratios were prepared by using a simple method that simultaneously combined a physical mixture and a platinum photochemical reduction. This method led to improved physicochemical properties such as low band gap, better Pt nanoparticle distribution on the surface, and the formation of different Pt species. Niobia content was also found to be an important factor in determining the overall efficiency of the Pt–TiO2–Nb2O5 photocatalyst in the glycerol reforming reaction. The photocatalytic results showed that Pt on TiO2–Nb2O5 enhanced hydrogen production from the aqueous glycerol solution at a 5 wt% initial glycerol concentration. The influence of different operating conditions such as the catalyst dosage and initial glycerol concentration was also evaluated. The results indicated that the best hydrogen and methane production was equal to 6657 μmol/L and 194 μmol/L, respectively after 4 h of UV radiation using Pt/Ti:Nb (1:2) sample and with 3 g/L of catalyst dosage. Moreover, the role of water in photocatalytic hydrogen production was studied through photocatalytic activity tests in the presence of D2O. The obtained results confirmed the role of water molecules on the photocatalytic production of hydrogen in an aqueous glycerol solution.

Gangliogliomas are well-differentiated, slow-growing tumors. The majority are gradeI of WHO. It appears predominantly in children and young adults. Most are located at the temporal lobe, and as symptomatology more frequent epileptic seizures of difficult pharmacological control. In general, they have a good prognosis after surgical resection. The anaplasic variant, considered to be gradeIII of the WHO, presents greater clinical and radiological aggressiveness. Leptomeningeal dissemination is exceptional in these types of tumors, but when diagnosed it presents a rapidly progressive and fatal course for the patient.

Crystalline orthorhombic Bi2WO6 powders were synthesized by a hydrothermal method from aqueous solutions of Bi(NO3)3 5H2O and Na2WO4 2H2O over a range of three selected pH values (2.0, 5.0 and 7.0), using NaOH as precipitating agent. The as-prepared catalysts were char- acterized by XRD, BET, FE-SEM, TEM, XPS and UV-vis spectroscopy. The effect of pH-synthesis on crystallinity, morphologies, surface area and optical absorption properties, were investigated. Although the pH has a marked influence on morphology, the nature of the precipitating agent (NaOH or TEA) also influences the morphology and surface structure composition, as it is observed in the present work. Three different probe molecules were used to evaluate the photo- catalytic properties under two illumination conditions (UV and Visible): Methyl Orange and Rho- damine B were chosen as dye substrates and Phenol as a transparent substrate. The photo-catalytic activities are strongly dependent not only on the pH used in the synthesis but also on the nature of the chosen substrate in assessing the photo-catalytic activities. Results were compared with those obtained when using TiO2(P25, Evonik) in the same experimental conditions. The photo- catalytic activity of one of the synthesised samples has been evaluated by exposing a mixture of Rhodamine B and Phenol in water, to different illumination conditions. Our results provide new evidences about the issue of whether dyes are suitable substrates to assess the activity of a photo-catalyst.

A highly faceted {001} TiO2 catalyst was hydrothermally synthesized by using Ti(IV)-isopropoxide precursor with aqueous HF addition. WO3 was synthesized by following a reported method. Coupled TiO2-WO3 samples were synthesized by adding the corresponding amount of WO3 to fluorinated TiO2 gel followed by a hydrothermal treatment. Additionally the synthesized systems were characterized by using X-ray powder diffraction (XRD), X-ray fluorescence spectrometry (XRF), field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), UV–vis diffuse reflectance spectroscopy (DRS) and N2-adsorption (BET) for specific surface area determination. The photocatalytic activity of the single and coupled oxides was measured by means of three model reactions: the photo-oxidation of phenol (as a colourless substrate) and methyl orange (as a dye) and the photoreduction of Cr(VI) as K2Cr2O7. The coupling of WO3 with a highly faceted {001} TiO2 makes it possible to optimize the photocatalytic properties of the faceted material. In fact, {001} faceted TiO2 by itself presents a substantial improvement with respect to commercial TiO2(P25), as it can implement its photoactivity after the incorporation of WO3 with promising results, which can reduce the limitations of TiO2 in terms of its photoactivity, taking advantage of a higher percentage of solar radiation.

New photocatalysts based on bismuth titanates doped with iron with outstanding visible photocatalytic activity were prepared by a facile hydrothermal method followed by incipient wetness impregnation. The starting material was composed by three phases; majority of Bi20TiO32 closely interconnected to Bi4Ti3O12 and amorphous TiO2. Fe doping increased the already very high visible activity of the original material. The high visible activity showed by these materials could be ascribed to a combination of several features; i.e. low band gap energy value (as low as 1.78 eV), a structure allowing a good separation path for visible photogenerated electron-holes pairs and a relatively high surface area. Fe doping could be acting as bonding paths for the bismuth titanates phases, and the amount of Fe on the surface was found to be a crucial parameter on the photocatalytic activity of the materials. Visible activity of the best photocatalyst was superior to UV-Activity of commercial TiO2 P25 used as reference in same experimental conditions.

Resumen: Objetivo: Identificar el patrón de medición de la automonitorización de la presión arterial (AMPA) más eficiente para el seguimiento del hipertenso en atención primaria. Diseño: Estudio validación de prueba diagnóstica. Emplazamiento: Equipo de atención primaria en Murcia. Población: Ciento cincuenta y tres hipertensos menores de 80 años que cumplieran con los criterios de inclusión; y con AMPA y monitorización ambulatoria de su presión arterial válidos. Mediciones principales: Realización de monitorización ambulatoria de presión arterial durante 24 h (MAPA). El protocolo de AMPA consistió en registrar 2 mediciones en la mañana y 2 en la noche durante 7 días. Con los registros obtenidos se establecieron los diferentes patrones de AMPA (7, 6, 5, 4, 3 días). Para el análisis utilizamos las curvas COR, el coeficiente de correlación intraclase y el diagrama de Bland-Altman. Resultados: Las mejores áreas bajo la curva para la presión sistólica de los diferentes patrones de la AMPA correspondieron al patrón de 4 días: 0,837 (0,77-0,90); y al de 3 días: 0,834 (0,77-0,90). En cuanto a la diastólica, el patrón de 7 días presentó un área bajo la curva de 0,889 (0,84-0,94); y en segundo lugar, coincidiendo con la misma cifra, los patrones de 3 y 4 días: 0,834 (0,83-0,94). No hubo diferencias significativas entre los coeficientes de correlación intraclase para las presiones arteriales sistólicas y diastólicas. El patrón de 3 días mostró en conjunto una menor dispersión en el diagrama de Bland-Altman. Conclusión: Proponemos el patrón de AMPA de 3 días para el seguimiento del paciente hipertenso, ya que no presenta una eficiencia inferior a los demás patrones. Abstract: Objective: To identify the most efficient measurement pattern of home blood pressure monitoring (HBPM) for the follow-up of hypertensive patients in primary care. Design: Validation study of a diagnostic test. Setting: Primary care team in Murcia, Spain. Population: One hundred and fifty three hypertensive patients younger than 80 years who met the inclusion criteria, who used HBPM and ambulatory blood pressure monitoring. Main measurements: Performing HBPM for 24 hours. The HBPM protocol consisted of recording 2 measurements in the morning and 2 in the evening for 7 days. With the records obtained, the different HBPM patterns were established (7, 6, 5, 4, 3 days). The ROC curves were used for the analysis, together with the correlation coefficients and the Bland-Altman plots. Results: The best areas under the curve for the systolic pressure of the different HBPM patterns corresponded to the 4-day pattern: 0.837 (0.77-0.90); and the 3 day one: 0.834 (0.77-0.90). As for diastolic pressure, the 7-day pattern had an area under the curve of 0.889 (0.84-0.94); followed by the 3 and 4 days patterns, which had the same statistical result both: 0.834 (0.83-0.94). There were no significant differences between correlation coefficients for systolic and diastolic blood pressures. The 3-day pattern showed a lower dispersion in the Bland-Altman plots. Conclusion: The 3 days HBPM pattern is proposed for the follow-up of the hypertensive patient, since it does not have an inferior efficiency to the other patterns. : Automonitorización presión arterial, Atención primaria, Riesgo cardiovascular, Keywords: Home blood pressure monitoring, Primary care, Cardiovascular risk

With the aim of improving the photocatalytic properties of a previously optimized zinc oxide photocatalyst, the effect of the incorporation of different amounts of Ag2CO3 on the aforementioned ZnO has been studied. For this purpose we report the synthesis, by means of simple precipitation procedures, of bare ZnO and Ag2CO3 samples as well as the coupled materials ZnO/Ag2CO3 (X) (where X = 1%, 2%, 4% and 5% in molar percentages). Both, single and coupled materials have been characterized by different techniques (XRD, XRF, N2-absorption, SEM, TEM, UV–vis/DRS and XPS). To assess the advantages or disadvantages that Ag2CO3 addition could have over the optimized ZnO, the photocatalytic properties have been established by following the photo-degradation of selected toxic molecules, both in the UV and in the visible, as well as using complementary techniques of liquid medium analyses (TOC and Atomic Emission Spectrometry with plasma ICP). Three selected substrates were chosen: Rhodamine B (RhB) as a dye, and phenol and caffeine as colourless recalcitrant toxic molecules. Our results suggest that although the use of Ag2CO3 could be beneficial to implement the optical absorption towards the visible region, however, other effects have to be bore in mind, such as the photo-corrosion of Ag2CO3 and the chemical structure of the chosen substrate, to elucidate whether the addition of Ag2CO3 has beneficial or detrimental effects on the photocatalytic properties of the coupled ZnO/Ag2CO3 materials.

The association between the intensity of physical activity and the incidence of cardiovascular diseases (CVD), irrespective of energy expenditure (EE), requires further study. Our objective is to examine this relationship using data from a large Spanish cohort. The Seguimiento Universidad de Navarra cohort is formed of university graduates recruited from March 1999 to October 2015. We included 18,737 adults free of CVD (mean age 38 years, 61% women), with a median follow-up of 10.3 years. We estimated the average intensity of leisure time physical activity (LTPA) using a validated questionnaire. We classified respondents into 3 groups: Inactive,6 average metabolic equivalents (METs) and ≥6 average METs. We used Cox proportional hazards models adjusted by the EE in LTPA (MET-h/week) and other confounding factors, to examine this association. During 1,72,299 person-years of follow-up, we registered 127 cases of CVD (myocardial infarction, stroke, and death due to cardiovascular causes). The adjusted hazard ratio for CVD was 0.76 (95% CI 0.48 to 1.21) in the lower intensity group, and 0.31 (95% CI 0.12 to 0.79) in the higher intensity group, compared with the inactive, with a linear trend (p = 0.03). In conclusion, given the same level of EE, those respondents engaged in higher intensity LTPA, had a lower risk of CVD.

Background An initial antidepressant effect when using deep brain stimulation (DBS) of the subcallosal area of the cingulate cortex (Cg25) to treat resistant depression that could be the result of electrode insertion has been described. We previously showed that electrode insertion into the infralimbic cortex (ILC; the Cg25 rodent correlate) provokes a temporally limited antidepressant-like effect that is counteracted by non-steroidal anti-inflammatory drugs, such as those routinely used for pain relief. Objective We characterized the effect of electrode insertion using functional neuroimaging and evaluated the impact of different analgesics on this effect. Methods The effect of electrode insertion into the ILC was evaluated by positron emission tomography. The effect of analgesics (ibuprofen, tramadol and morphine) on the behavioral effect induced by electrode insertion were evaluated through the forced swimming test and the novelty suppressed feeding test. Furthermore, glial fibrillary acidic protein (GFAP) and p11 expression were measured. Results Electrode implantation produces an antidepressant- and anxiolytic-like effect, a local decrease in glucose metabolism, and changes in several brain regions commonly related to depression and the antidepressant response. Ibuprofen counteracted the behavioral and molecular changes produced by electrode insertion (changes in GFAP and p11 protein expression). However, analgesics with no anti-inflammatory properties (e.g., tramadol) neither counteract the behavioral effects of electrode implantation nor the molecular mechanisms triggered. Conclusions Analgesics without anti-inflammatory properties may not limit the transient benefit produced by electrode insertion reducing the time required to achieve remission in depressive DBS patients.

ZnO nanoparticles have been previously synthesized by a facile precipitation procedure by mixing aqueous solutions of Zn(II) acetate and dissolved Na2CO3 at pH ca. 7.0 without the addition of a template. The as-prepared ZnO material was anealed at 400 °C in air for 2 h. The Pt-ZnO catalysts (0.5 or 1.0 Pt wt.%) were obtained by photochemical deposition method on the surface of the prepared ZnO sample, using hexachloroplatinic acid (H2PtCl6). It has been shown that Zn2+ is lost from the photocatalyst to the medium and a replacement of the cationic vacancies of Zn2+ by Pt4+ cations occurs during the platinization process of the ZnO samples, regardless of whether the platinum metal photodeposition process. The as-prepared catalysts were characterized by XRD, BET, FE-SEM, TEM, XPS and diffuse reflectance spectroscopy (DRS). Three different probe molecules were used to evaluate the photocatalytic properties under UV-illumination: Methyl Orange and Rhodamine B were chosen as dye substrates and Phenol as a transparent substrate. High conversion values (ca. 100%) and a total organic carbon (TOC) removal of 90–96%, were obtained over these photocatalysts after 160 min of UV illumination. In general, it was observed that the presence of Pt on ZnO affects the lattice parameters and the crystallite size. Although ZnO can completely degrade RhB, MO and Phenol totally in ca. 60 min, the process is more efficient for Pt–ZnO photocatalysts., This work was supported by research fund from Project Ref. CTQ2015-64664-C2-2-P (MINECO/FEDER, UE). XPS and others research services of CITIUS University of Seville are also acknowledged. We thank the University of Tolima for economic support in the studies commission of Cesar Augusto Jaramillo Páez.

The properties of Nb2O5 strongly depend on its synthesis procedure as well as the conditions of ulterior thermal treatment. We report the synthesis of Nb2O5 powders prepared by sol-gel precipitation method using niobium(V) ethoxide as precursor. Two chemical routes were chosen: the presence of tryethyl amine (TEA) as precipitant/template agent, or the oxidant peroxide method. In addition, microwave-assisted activation was also used. The as-prepared samples by the above procedures were amorphous. Structural changes upon heating from room temperature up to 800 °C were investigated by X-ray powder diffraction technique combined with thermogravimetric analysis. The sequential thermal treatment up to 800 °C promotes the crystallization of hexagonal phase to orthorhombic phase whereas the ulterior cooling to room temperature lead to a mixture of both phases. Samples calcined at selected temperatures of either 600 °C or 800 °C for 2 h, were characterized by XRD, SEM, N2-adsorption and diffuse reflectance spectroscopy (DRS). The synthetic approach routes as well as the combined microwave activation followed by ulterior thermal treatment lead to changes not only on particle size but also on the textural properties of the synthesized catalysts. The catalysts synthesized have been evaluated using Rhodamine B (RhB) as a substrate, under both UV and visible lighting conditions. None of the catalysts synthesized showed activity in the visible. Under UV-illumination conditions, some of the catalysts exhibited a relatively low photoactivity in the degradation of RhB, which is associated with a photo-sensitizing effect. However, the addition of Ag+ ions considerably increased the activity of all the catalysts in the degradation of RhB under UV-illumination conditions. A mechanism is proposed to explain the photo-induced processes obtained, leaving the door open to the possible implications of the observed results in relation to the interaction of RhB dye with noble metal nanoparticles such as silver., This work was supported by research fund from Project Ref. CTQ2015-64664-C2-2-P (MINECO/FEDER UE). We thank the University of Tolima for economic support in the studies commission of César Augusto Jaramillo Páez.

{0 0 1} faceted TiO2 catalysts are hydrothermally synthesized by using titanium(IV) isopropoxide and butoxide precursors (ISO and BUT TiO2 samples) together with HF addition. Their activity and stability are evaluated in the catalytic condensation of light oxygenated organic compounds present in an aqueous model mixture simulating a real bio-refinery effluent, under moderate operation conditions. High {0 0 1} faceted TiO2 catalysts show organic products yields superior to those attained with other TiO2 samples (anatase, rutile, and P25). This enhanced catalytic activity relates to their physico-chemical and textural properties, such as high surface area (¿100 m2/g), regular morphology (platelets conformed by partially agglomerated TiO2 nanoparticles), and adequate Lewis acidity. XRD and Raman measurements evidence the unique presence of anatase crystalline phase in both ISO and BUT materials, in which the use of HF during synthesis produces the preferential growth of TiO2 crystals mainly exposing the {0 0 1} plane. This effective {0 0 1} facet exposition directly determines catalytic results. Moreover, TiO2 ISO catalyst shows outstanding stability under reaction conditions, maintaining practically unaltered their activity after several re-uses. In particular, Lewis acid sites present in TiO2 faceted materials are more stable in the presence of organic acids under aqueous environments. This opens new possibilities for the application of these materials in the valorization of light oxygenated compounds present in biomass-derived aqueous effluents., Financial support by Spanish Government (CTQ-2015-67592, CTQ-2015-68951-C3-1, CTQ-2015-64664-C2-2-P and SEV-2016-0683) is gratefully acknowledged. A.F-A. thanks “La Caixa-Severo Ochoa” Foundation for his PhD fellowship.

The health benefits of the Mediterranean diet (MedDiet) and of physical activity (PA) have been widely documented. However, no longitudinal studies have investigated their combined effect on mortality. We assessed the individual and combined effects of adherence to the MedDiet and PA on all-cause mortality. We used data from 19,467 participants from a prospective cohort of Spanish university graduates, the SUN cohort, followed-up between December 1999 and February 2016. Adherence to the MedDiet was assessed using four different dietary scores, categorizing the quantitative scores into tertiles of adherence. To assess multiple dimensions of PA, an 8-item score was built. Multivariable Cox regression models were used to study the individual and combined relationship of adherence to the MedDiet and PA with all-cause mortality. During a median follow-up of 10.3years, we registered 305 deaths. Compared with the lowest adherence to the MedDiet (

The energy performance certificate (EPC) is the core source for the European Union (EU) to obtain information about the efficiency levels of building stock and plan energy target paths. For this reason, and due to its wide variety of applications, it is important to ensure its quality. This study evaluates the quality of a representative EPC sample taken between 2014 and 2019 following the control methodology established in the Basque Country. The results show that inaccuracies exist: 78.1% of the sample presents at least one inconsistency, and the root mean square of relative error for non-renewable primary energy consumption (nrPEC) and CO2 emissions is 20.3% and 22.0% respectively. Another finding of this investigation is the upward evolution of errors. Finally, estimates show that any EPC in the Basque Country can have a relative error in the range of ±39.98% for nrPEC or ±43.23% for CO2 emissions with a probability of 95%, and the same error distribution in positive or negative direction. This suggests that at least half of EPCs were not the result of deliberate wrongdoing but may have been due to a conservative attitude or misconceptions on the part of the certifier.

Product quality is a key determinant of a firm’s competitiveness, though previous literature lacks a clear definition of product quality for organic markets. This study proposes a new model that highlights consumers’ perceptions of specific organic product attributes: environmental protection, health, and hedonic aspects. Quality assessments based on these three perceptions depend on other factors too, such as the product category and the cognitive style consumers use to process information. A study with 209 respondents offers empirical evidence that environmental protection, health and hedonic perception positively affect quality perception and that the effect of perceptions of environmental protection on perceived quality is greater for organic products in a virtue category (e.g., yogurt) than a vice category (e.g., chocolate). Hedonic perceptions also have a greater impact on perceived quality when consumers are intuitive versus analytical. These findings suggest some important theoretical and managerial implications.

AgBr/WO3 composite photocatalysts with different selected molar AgBr/WO3 ratios were prepared and widely characterized by XRD, N2-adsorption, SEM, TEM, UV–visible/DRS and XPS techniques. The samples were tested using rhodamine B (RhB) or caffeine, under two illumination conditions (UV and visible light). Although AgBr and WO3 pristine materials have relatively low band gap values (2.6 eV and 2.8 eV, respectively), they exhibit low or no photocatalytic activity under visible light, at least for caffeine degradation. This fact may be mainly related to a high recombination rate of photogenerated charge carriers in these samples. However, the coupling of both leads to a substantial improvement in the degradation of caffeine and RhB under both UV and visible lighting conditions. The increased photocatalytic activity found in the coupled systems with respect to the pristine materials can be attributed to the formation of a type II heterostructure in the coupled AgBr/WO3 samples. Our results show that for AgBr/WO3 coupled systems, kinetic degradation profiles have clear dependence on the molar percentages of the coupled pristine materials, as well as on the nature (sensitizing or not sensitizing effect) of the substrate. For caffeine photodegradation, the best performance was obtained when AgBr/WO3(10–15%) catalysts were used. The AgBr/WO3(20%) sample showed the best photocatalytic activity for rhodamine B degradation, exhibiting also excellent dark adsorption capacity (40–45%). Additionally, studies of activity in five consecutive tests showed a good RhB degradation during the successive reuses being involving a N-de-ethylation mechanism with the main O2•− radicals participation; relatively low mineralization percentages were observed, both under UV and visible light conditions. In these successive runs, no silver leaching to the medium was observed but a change from AgBr towards Ag2CO3 and/or AgxO was produced at the catalyst surface. These features should be known in the use of these systems as potential photocatalysts for practical applications.

Introduction Emerging evidence suggests that vigorous physical activity may be associated with higher cardioprotective benefits than moderate physical activity. This study aimed to assess the long-term relationship between the intensity of leisure time physical activity (LTPA) and the risk of developing metabolic syndrome (MS) in a prospective cohort study. Methods The Seguimiento Universidad de Navarra (SUN) Project comprises Spanish university graduates. Participants ( n =10,145) initially free of MS were followed for a minimum of 6 years (2008–2014). Analysis was conducted in 2015. Physical activity was assessed though a validated questionnaire. The intensity of each physical activity was measured in METs. The intensity of LTPA was estimated by the ratio between total METs/week and total hours of LTPA/week, obtaining the mean METs/hour of LTPA. MS was defined according to the harmonizing definition. The association between the intensity of LTPA (METs/hour) and MS was assessed with logistic regression models adjusting for potential confounders. Results Among 10,145 participants initially free of any MS criteria, 412 new MS cases were observed. Vigorous LTPA was associated with a 37% relatively lower risk (AOR=0.63, 95% CI=0.44, 0.89) compared with light LTPA. For a given total energy expenditure, independent of the time spent on it, participants who performed vigorous LTPA exhibited a higher reduction in the risk of MS than those who performed light to moderate LTPA. Conclusions Vigorous LTPA was significantly associated with lower risk of developing MS after a 6-year follow-up period.

In this work, a new photocatalyst based on bismuth titanates with outstanding visible photocatalytic activity was prepared by a facile hydrothermal method. The synthesised material showed visible activity as high as UV activity of commercial TiO P25 under the same experimental conditions for phenol degradation. A wide characterisation of the photocatalyst was performed. The material was composed of three phases; majority of BiTiO closely interconnected to BiTiO and amorphous TiO. The high visible activity showed by this material could be ascribed to a combination of several features; i.e. low band gap energy value (2.1 eV), a structure allowing a good separation path for visible photogenerated electron-holes pairs and a relatively high surface area. This photocatalyst appeared as a promising material for solar and visible applications of photocatalysis.

Resumen Objetivo Valorar el riesgo de rotura uterina (RU) en el intento de parto vaginal despues de cesarea y determinar los factores de riesgo. Metodos Revision sistematica consultando las siguientes bases de datos: PubMed (MEDLINE), Biblioteca Cochrane Plus, Embase, Nursing@Ovid, Cuidatge y Dialnet. La consulta se realizo entre enero y marzo de 2015. Se utilizaron los descriptores MeSH: vaginal birth after cesarean; uterine rupture; labor induced y labor obstetric o trial of labor. No hubo restriccion de fecha ni idioma. La seleccion de articulos se realizo por 2 revisores de forma estandarizada, independiente y no cegada. Se llevo a cabo una revision critica del resumen y, cuando fue necesario, se accedio al texto completo. Se incluyeron articulos prospectivos y retrospectivos. Resultados Se incluyeron un total de 39 documentos por su interes y relevancia. Se encontraron escasos ensayos clinicos. Los rangos de incidencia de RU en los resultados de los trabajos analizados han oscilado entre 0,15-0,98% en trabajo de parto espontaneo; 0,3-1,5% en estimulacion e induccion con oxitocina, y 0,68-2,3% en inducciones con prostaglandinas. Conclusiones El exito del parto vaginal tras cesarea es importante y mejora cuando las condiciones son optimas. Sin embargo, no esta exento de riesgos, siendo el principal la RU. La induccion del parto con oxitocina y/o prostaglandinas figura como el principal factor de riesgo para la RU, mientras que el inicio espontaneo del parto y el antecedente de un parto vaginal son factores protectores.

Mixed oxides, α-Fe2O3/Bi2WO6, were prepared using a mechanical mixing procedure by adding to the Bi2WO6 previously obtained by hydrothermal method the corresponding amount of a prepared α-Fe2O3, the latter obtained by thermal decomposition of Fe(NO3)∙9H2O. The physicochemical surface, structural, morphological characteristics and optical properties of the samples, single and mixed, were determined by BET, XRD, FE-SEM, XPS and UV–vis diffuse reflectance spectroscopy. UV–vis diffuse reflectance spectra showed that incorporating a 5%wt. of α-Fe2O3 to the corresponding amount of Bi2WO6 sample broadened the visible light absorption of Bi2WO6 as expected. The photocatalytic activity, of single and mixed catalysts, to degrade a selected dye such as Methyl Orange (MO) as well as the transparent substrate Phenol (Ph) was studied, in aqueous medium (pH ≈ 5.5) under UV and sun-like illumination conditions in the absence and presence of H2O2. In the present study the use of a α-Fe2O3-Bi2WO6/H2O2 system demonstrate much higher photocatalytic efficiency to degrade both MO and Ph than pristine Bi2WO6or α-Fe2O3, single or mixed. Using the system α-Fe2O3-Bi2WO6/H2O2, around 85% of MO was degraded in 60 min under sun-like illumination whereas 100% was degraded in 60 min under UV-illumination. However, just around 30% of Ph was degraded in 120 min in the α-Fe2O3-Bi2WO6/H2O2 system under sun-like illumination whereas around a 95% was degraded in 90 min under UV-illumination. Under UV-illumination, the generation of hydroxyl radicals is favorable; whereas under sun-like illumination, only the small fraction of the UV can produces the radical dotOH. Under illumination, the H2O2 could react with photoinduced electrons from the photocatalysts leading to the production of hydroxyl radicals (radical dotOH).

Composites (AgBr/SnO2) comprised of AgBr and SnO2 with different molar % of bare SnO2, have been synthesized by simple precipitation methods; the bare SnO2 used, was synthesized by hydrothermal procedure. Samples have been characterized by X-ray diffraction (XRD), N2-adsorption, UV–vis diffuse reflectance spectroscopy (DRS), scanning electron microscopy (SEM), Transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS). Photocatalytic activity of the as-prepared photocatalysts was evaluated through photocatalytic degradation of rhodamine B (RhB) and caffeic acid (CAFA) under UV and Visible illumination. In photocatalytic degradation studies, for both substrates, conversion rates of around 95% were found in 45 min of both UV-illumination and 85% under visible lighting. These conversion rates were superior than the conversion rates of pure parental components, AgBr and SnO2 under the same experimental conditions. At least, for RhB no loss of photocatalytic activity has been observed after five recycles although the mineralization degree progressively diminished along the recycles. The enhanced photocatalytic degradation of AgBr/SnO2 compounds was attributed, in part, to a synergistic increase in adsorption viability, as well as to the effective separation of photoinduced load carriers that resulted from the formation of a heterojunction according to the type II junction. Radical scavengers’ experiments indicated that active oxidant species as O2.−, ·OH and h+ all are involved in this photocatalytic system, although it seems that O2.− played the major role in the photocatalytic degrading of RhB by AgBr/SnO2 composites. In summary, coupling AgBr with SnO2 remarkably improves the photocatalytic activity under both UV and visible-illumination with respect to the parental components. These features open the route to future applications of this material in the field of environmental remediation.

ZnWO4 based powder photocatalyst have been successfully prepared by calcining a co-precipitated precursor (ZnWO) obtained from aqueous Zn2+ and WO42− solutions at pH = 7, without surfactants addition. The as-formed sample was characterized by XRD, N2-absorption, SEM, TEM, DRS and XPS. Both techniques, XRD and XPS results showed that prepared sample corresponds to a crystalline, Zn-enriched composition, ZnWO4 indicating the formation of a ZnWO4-(ZnO) composite, whit ca. 10 wt.-% of ZnO confirmed by XRF analysis. Photocatalytic activities towards degradation of Rhodamine B (RhB), Methyl Orange (MO) and Phenol, under UV-illumination, was investigated not only by monitoring the percentages of conversion of substrates, but also by estimating the corresponding percentages of mineralization that accompany the photocatalytic process. Comparative substrate-conversion rates estimated per surface area unit of catalyst, showed that the activity for ZnWO4-(ZnO) composite is similar to that for TiO2(P25), at least for MO and RhB, and even higher that for TiO2(P25) in respect to phenol conversion. By adding TEA to the synthesis procedure, a composite named as ZnWO4-ZnO-(pH = 10)-600 is generated, which has a higher proportion of ZnO (ca. 39 %) and superior specific surface area than the so-called ZnWO4-(ZnO) sample. Furthermore, the photocatalytic degradation of MO using the former material indicates that it is superior to ZnWO4-(ZnO) and even that TiO2(P25) itself under the same operational conditions.

In this work, titanium dioxide has been modified by sulfation, fluorination and simultaneous Pt nanoparticles deposition; the influence of these treatments on the photocatalytic activity of this oxide has been studied. A complete characterization study was carried out and it was observed that sulfation, fluorination and metallization were important factors influencing the TiO 2 properties. The photocatalytic activity of the materials prepared was evaluated in the phenol degradation and it was found that TiO 2 fluorination significantly increased the phenol photodegradation rate, compared with bare TiO 2 , sulfated TiO 2 or the commercial TiO 2 Degussa P25. It was also found that Pt photodeposition on sulphated TiO 2 notably increased the photocatalytic activity of this oxide, while Pt on fluorinated TiO 2 did not modify significantly the phenol photodegradation rate.

The synthesis of mesoporous TiO2 nanosheets is reported using Ti(IV) Isopropoxide as Ti(IV) precursor. A sol-gel process combined with microwave activation is used. Three different halogenhydric acids (HX), were used to peptise the sol: HF(ac), HCl (ac) and HBr (ac). The three obtained TiO2-I(HX) samples were characterized by XRD, XRF, N2-adsorption, SEM, TEM, DRS and XPS. The three synthesized samples have high values of specific surfaces (between 100 m2/g and 200 m2/g) and similar band gap values (3.2–3.3 eV). The analysis of the surface composition by XPS confirms the presence of the halogenated species (F, Cl or Br) on the surface of each ones of the samples. The nanometric size (ca 5 nm) of the particles for each of the three samples was confirmed by XRD and by TEM. On the other hand, the nature of the halogenated acid used plays a role in the composition of the phases. While the TiO2-I (HF) sample was 100 % anatase, the other samples turned out to be biphasic, showing anatase/rutile in the TiO2-I(HCl) sample and anatase/brookite in the TiO2-I(HBr) sample. The samples were tested under two illumination conditions (UV and visible light) using rhodamine B and caffeine. The indirect role of the halide agent on the photocatalytic activities thereof is discussed.

Pt–TiO2–Nb2O5 heterojunction was synthetized and studied for the photocatalytic removal of diclofenac (DCF) and ketoprofen (KTF) under UV light irradiation. The physical-chemical properties of the prepared catalysts were analysed by different characterization techniques revealing that the lowest platinum nanoparticle size and the better metal distribution was observed in Pt–TiO2–Nb2O5 sample. The Pt–TiO2–Nb2O5 heterojunction possessed the best photocatalytic activity toward both the photodegradation and mineralization of the two selected pollutants. The optimal photocatalyst showed a DCF and KTF mineralization rate of 0.0555 and 0.0746 min−1, respectively, which were higher than those of Pt–TiO2 (0.0321 min−1 for DCF and 0.0597 min−1 for KTF). The experiments driven to analyse the effects of free radical capture showed that ·OH, ·O2− and h+ have a primary role in reactive during the photocatalytic reaction. The improved photocatalytic performances of the Pt–TiO2–Nb2O5 heterojunction could be argue by a direct Z-scheme mechanism in which the Pt0 nanoparticles could act as a bridge between TiO2 and Nb2O5, improving the electron-hole separation and, ultimately, enhancing the photocatalytic removal rate of both DCF and KTF.

Iron (III) was incorporated, to the surface of a synthesized ZnO, using two nominal molar percentages of Fe (III): 1% and 5% Fe relative to ZnO. Samples dried and calcined at 200 °C and 400 °C for 2 h, were characterized by XRD, XPS, XRF, N2-adsorption-BET and (UV–vis)-DRS. Photocatalytic activities of the catalysts were assessed based on the degradation of rhodamine B (RhB) and caffeine (CAF) in aqueous solution under two irradiation conditions: UV and visible light illumination. Prior to the photocatalytic tests, the interaction of each one of the substrates with either Fe(III) or Fe(II) was studied in homogeneous medium under UV-illumination and oxygenated environment. It was found that Fe (III) can play an important role in homogeneous media in the photoassisted degradation, both of rhodamine B and caffeine, while Fe (II) does not exert a relevant role in the photoassisted degradation of the referred substrates. Fe–ZnO samples display similar or poorer performance than pure ZnO in the presence of UV light for both studied substrates. The phenomenon can be attributed to the formation of either goethite or ZnFe2O4 at the ZnO surface where the coupled Fe3+/Fe2+ can act as recombination centers for the photogenerated charges. On the contrary, all Fe–ZnO samples showed enhanced photocatalytic activity under visible illumination which seems to be independent of the iron content. In this context, the mechanisms for photoassisted degradation of both the substrates in homogeneous medium and photocatalytic degradation are discussed, as well as the role of Fe in the photodegradation processes.

In this work, a previously optimized synthesized ZnO photocatalyst was modified with different molar percentages of Ag3PO4 through a facile in situ precipitation–deposition method and then characterized by different techniques (XRD, XRF, BET, UV–vis DRS, SEM, TEM and XPS). The incorporation of Ag3PO4 produces important changes in the light absorption properties with a significant absorbance in the visible region observed for ZnO modified with different amounts of Ag3PO4; the optical absorption intensity in the visible region of the coupled ZnO/Ag3PO4 increases as the molar percentages of Ag3PO4 increases, evidencing a clear dependence on the content of Ag3PO4. However, this work shows that the incorporation of Ag3PO4 in almost all cases reduces the photocatalytic capacity of ZnO, except when it is used in a specific percentage of 10 % and only being more active against rhodamine B and not on the Caffeine. SEM images and elemental mapping indicate that Ag3PO4 disperses very well in the ZnO particles, exhibiting an almost homogeneous distribution, showing zones with cumulus of Ag3PO4 (rich in P-Ag) in contact with ZnO-zones (rich in Zn). All the prepared photocatalysts were tested in the photocatalytic degradation of rhodamine B as a dye, and caffeine as a toxic and persistent emerging compound under UV and visible light illumination. It is reported that not only the ZnO:Ag3PO4 ratio is an important factor that influences the photocatalytic process of substrate degradation, but also the nature of the substrate has an important influence on the photocatalytic behavior of the materials under both UV and visible illumination. Thus, pristine Ag3PO4 showed high photocatalytic degradation for rhodamine B, while for caffeine negligible photocatalytic degradation was found in both the UV and visible regions. The thermal- and photo-stability of the coupled system was also studied. At least, for rhodamine B no loss of photocatalytic activity has been observed after five recycles although the mineralization degree progressively diminished along the recycles.

This study proposes a direct synthetic route to single titanate sheets through the mild and versatile conditions of the >chimie douce>. The stages of the production include the complexation of the titanium alkoxide precursor by benzoic acid, the formation of titanium oxo-clusters and their controlled transformation into single sheet titanates during the hydrolysis stage. The resulted material appears to be an excellent precursor for self-organized TiO2 nanotubes formation which presents an excellent activity as photocatalyst in the photo-degradation of phenol Junta de Andalucía TEP106 España Miniterio de Ciencia e innovación CTQ2011-26617-C03-02

TiO 2 –SiO 2 mixed oxides were synthesized by the sol–gel technique using three different acids, i.e., acetic, sulfuric, or chlorhydric acid. Their photocatalytic behavior was evaluated on the phenol oxidation in liquid phase and correlated with the characterization results. It was found that the kind of acid used during the preparation strongly influences the phase composition and stability of the TiO 2 phases incorporated in the silica structure as well as the photocatalytic activity. In all cases, silica introduced a dispersive effect that stabilized the TiO 2 crystalline phases upon calcination at 700 °C. SO 4 2− and CH 3 COO − ions stabilized the anatase phase at high calcination temperatures (700 °C) leading to samples with the highest photoactivities. Cl − ions induced the formation of traces of rutile and brookite resulting in a lower photoactivity. The highest photoactivity was achieved with the catalyst synthesized with acetic acid and calcined at 700 °C (TS1-700-ace). The photocatalytic performance of this material was even better than that obtained with the commercial catalyst Degussa P-25.

The Meerwein–Ponndorf–Verley (MPV) reaction involves the hydrogen-transfer reduction of a carbonyl compound by an alcohol used as hydrogen donor. The process is catalysed by both homogeneous and heterogeneous catalysts. The latter can be of the acid or basic type. In this work, we used delamination and ion-exchange in combination to obtain delaminated solids from layered double hydroxides (LDHs). Three Mg/Al LDHs (Mg/Al ratio = 2) containing carbonate, hydroxyl or dodecylbenzenesulphonate (DBS) as interlayer anion were prepared using a coprecipitation method or by rehydration of the solid obtained by calcinations of carbonate containing LDH. The X-ray diffraction patterns for LDHs exhibited the typical lines for LDHs intercalated with carbonate, hydroxyl or DBS ions. The DBS-containing LDH was delaminated by sonicating at 60 °C a suspension of this solid in 1-butanol. The DBS ions in the delaminated LDH could be exchanged by nitrate or hydroxyl ions by stirring a suspension of this delaminated LDH in 1-butanol containing an appropriate amount of Ca(NO 3 ) 3 of Ca(OH) 2 , respectively. The resulting delaminated solids consisted of brucite-like nanolayers excess charge in which was countered by dodecylbenzenesulphonate, nitrate or hydroxyl ions. Some of these solids exhibited moderate catalytic activity in the MPV reaction of benzaldehyde with 2-propanol. The reaction was conducted at 82 °C (0.06 mol of 2-propanol was treated with 0.003 mol of benzaldehyde in the presence of 1 g of catalyst). Calcining at 450 °C the delaminated LDHs, however, provided solids with a high surface activity that made them highly effective catalysts for the reaction. The catalyst obtained by calcining delaminated LDH containing hydroxyl ions provided the best catalyst (100% conversion after 2 h of reaction) and has been used in the MPV reaction of other aldehydes with excellent results.

Nanoparticles of CoxZn1-xO system with a nominal composition of x=0.2 were synthesized by the Solution Combustion Method (SCM). Structural and morphological studies as well as the chemical composition of the material were widely investigated by different techniques. Photocatalytic activity under UV and Visible illumination was studied by means of the Remazol Brilliant Blue dye (RBB) oxidation reaction. The effect of different experimental parameters, such as the initial dye concentration, photocatalyst mass, pH or hydrogen peroxide concentration on the RBB discoloration under UV irradiation was studied. Optimal experimental conditions were found to be a photocatalyst mass of 1 g.L-1, dye concentration of 20 mg.L-1 and solution pH of 11. Hydrogen peroxide addition was found to have no effect in the photocatalytic behavior of the material in the range of concentration studied (0 to 6•10-4 M). The optimal parameters were chosen to investigate the degradation of RBB under UV-illumination and just visible illumination. It was observed that the UV-photocatalytic property of pristine ZnO for the RBB removal was scarcely improved after cobalt-incorporation, whereas the effect of cobalt incorporation into ZnO greatly enhanced the RBB conversion under visible illumination. Even more interesting is that, under same experimental conditions, the visible efficiency of the Co-ZnO system is the same that the one showed under UV illumination, i.e. the system does not loose efficiency when illuminated only with visible light.

TiO 2 Degussa P25, TiO 2 prepared by sol–gel submitted to sulfation pre-treatment and some metallized catalysts obtained by photodeposition of Au or Pt over the sulfated TiO 2 , were evaluated in the reaction of ethanol photo-oxidation. FT-IR spectroscopy was used to investigate the surface features of the photocatalysts, identifying adsorbed species and following the evolution of intermediate products in the ethanol photo-oxidation reaction. Nature of surface acidity in terms of Bronsted and Lewis centers was also studied. Results showed that sulfation pre-treatment and metallization were important factors influencing the selectivity. Acetaldehyde was the main oxidation product on sulfated TiO 2 ; in the case of P25 also acetates production was observed. The photodeposition of metals had a detrimental effect on the selectivity to acetaldehyde; on metallized catalysts the formation of stable secondary intermediates was detected. Based on these findings, a reaction pathway for the ethanol photo-oxidation over the different photocatalysts, via acetaldehyde or via acetate formation is proposed.

The photocatalytic activities of several Bi 2 WO 6 and TiO 2 /Bi 2 WO 6 materials with different activated carbon (AC) contents were studied for Rhodamine B ( RhB ) (and Phenol) photodegradation under UV–vis and vis illumination. A wide characterization of the materials was carried out. The addition of AC strongly affected the Bi 2 WO 6 morphology although not the crystalline phase. Even in the material with the lowest AC content (2 wt% nominal content) a structure with hierarchical porosity was formed. AC presence increased the initial reaction rates in the degradation of RhB . An important improvement in the photoactivity under both UV–vis and vis illumination conditions was obtained with the lowest AC content (2 wt%) when compared to the pristine material Bi 2 WO 6 or to the systems with higher AC additions. AC/TiO 2 /Bi 2 WO 6 materials were also improved in comparison to the TiO 2 /Bi 2 WO 6 heterostructure without carbon. The improvement cannot be only ascribed to adsorption capability and surface area effects. A mechanism explaining the role of AC on the photocatalytic activity improvement is proposed.

In this study, the antibacterial activity of a grape seed extract (GSE) was examined against different Campylobacter strains. Growth inhibition was in the range from 5.08 to 6.97 log CFU/ml, demonstrating the strong capacity of the GSE to inhibit Campylobacter growth. Further dilution of the extract showed a minimal inhibitory concentration (MIC) of 20 mg/l and a minimal bactericidal concentration (MBC) of 60 mg/l against Campylobacter jejuni. GSE was fractioned by RP-HPLC and phenolic composition was determined by HPLC-DAD and HPLC-MS. The phenolic profile of GSE mainly consisted on flavonols, phenolic acids, catechins and proanthocyanidins, and anthocyanins. Among them, catechins and proanthocyanidins were the major compounds, representing 77.6% of total phenolic compounds determined. The analysis of the antibacterial activity against C. jejuni of the collected fractions showed that phenolic acids, catechins and proanthocyanidins were the main responsible of the behavior observed. These results showed that identification and quantification of the individual phenolic compounds of GSE could be feasible to standardize the production process to obtain an enriched extract potentially useful to control Campylobacter in the food chain. © 2012 Elsevier Ltd., This work was founded through Projects AGL 2009-07894 from the CSIC, ALIBIRD-CM-P 2009/AGR-1469 (Comunidad de Madrid) and CSD2007-00063FUN-C-FOOD (CONSOLIDER INGENIO 2010).

The influence of Pt features, such as particle size, dispersion, oxidation state and amount of metal, on the improvement of the photoactivity of TiO 2 for phenol and methyl orange degradation was studied. The size of Pt deposits was precisely controlled by changing deposition time under medium light intensity during the photodeposition, with sizes ranging from 3 to 6 nm. Pt oxidation state was also strongly dependent on the photodeposition time. Photocatalytic activity results showed that the fraction of metallic platinum (Pt 0 ) was the crucial factor for the improvement of the activity. When the fraction of Pt 0 was similar, metal deposit size became the dominant parameter influencing the activity. The influence of the substrate to be degraded (phenol or methyl orange) was also studied.

The photocatalytic activity, under sunlike illumination, for Rhodamine B ( RhB ) degradation using Bi 2 WO 6 –TiO 2 samples, is reported. Two different kinds of Bi 2 WO 6 –TiO 2 samples were studied, obtained by distinct methods: first, a mechanical mixing, by adding to synthesized nanosheet-like Bi 2 WO 6 powder the corresponding amount of TiO 2 nanoparticles (P25) in order to obtain physical mixtures of both catalysts with different percentages of TiO 2 (5, 10 and 50 wt%); second, a single Bi 2 WO 6 –TiO 2 heterostructure was prepared by adding commercial TiO 2 -P25 to the Bi 2 WO 6 precursors (50 wt%) prior to the hydrothermal treatment, thus obtaining a sample with “in situ” TiO 2 incorporation. Comparisons between the photocatalytic behaviour of these samples and those exhibited by the single materials Bi 2 WO 6 and TiO 2 (P25) were carried out, in order to establish the effect not only of the TiO 2 addition but also of the way in which TiO 2 (P25) is incorporated. The role of each single photocatalyst in the mixtures in the RhB degradation and mineralization under sunlike and just visible illumination was also studied.

The influence of experimental conditions during the photodeposition in the preparation of supported Au on TiO2 has been studied. Besides preparation pH, light intensity and deposition time showed to have a high influence on the final properties of gold deposits. Photodeposition using illumination with a high light intensity UV–vis lamp (140 W/m2 UVA range) resulted to be an ineffective method for obtaining nanoparticles of gold on the titania, producing very large and poorly distributed gold deposits. Thus obtained materials did not show any important improvement of their photocatalytic activity tested for phenol oxidation. By contrast, photodeposition using a low light intensity of illumination (0.15 W/m2 UVA range), produced materials with notably improved photocatalytic activity. The illumination with such a low light intensity allowed the control of the amount, aggregation and oxidation state of gold by changing deposition time, enabling a feasible method of tailoring Au–TiO2 with the appropriate properties for a high photocatalytic activity. Best photocatalytic behaviour for phenol photodegradation was obtained for Au–TiO2 samples prepared by photodeposition at low light intensity with 120 min photodeposition time for catalysts with a 0.5% and 1% nominal content of gold and with 60 min photodeposition time for catalyst with a 2% nominal content of gold.

A comparative study of the photodeposition of Pt, Au and Pd under the same experimental conditions onto pre-sulphated and non-sulphated TiO2 was performed. Morphological and surface characterisation of the samples as well as photocatalytic activity for phenol photooxidation was studied. The influence of sulphate pre-treatment on the deposits size and dispersion onto the TiO 2 surface, and photodeposition yields with the different metals were also analysed. The photocatalytic activity of the doped materials was then investigated, observing that catalytic behaviour can be correlated to physical characteristics of the samples determined by (XRD) X-ray diffraction, (XPS) X-ray photoelectron spectroscopy, (XRF) X-ray fluorescence spectrometry and (TEM) transmission electron microscopy. Sulphate pre-treatment was found to influence both the level of dispersion and the size of metal clusters on the TiO2 surface. Sulphation and metallisation of samples was found to produce a synergistic enhancement in photoactivity for the degradation of phenol. The photoactivity of the catalysts with respect to the doped metal species was ordered Pt > Pd > Au. © 2010 Elsevier B.V. All right reserved., Financial support by the Spanish Ministerio Ciencia e Innovación (Project Ref. CTQ2008-05961-CO2-01) and Junta de Andalucía (P06-FQM-1406) are acknowledged

Highly efficient Bi(2)WO(6)-TiO(2) heterostructure is synthesized by means of a hydrothermal method having highly photoactivity for the degradation of Rhodamine B under sunlike irradiation. From the structural characterization it has been demonstrated that TiO(2) is incorporated on the Aurivillius structure. Interesting synergetic effect between TiO(2) and Bi(2)WO(6) leads to an improved charge carrier separation mechanism, causing the excellent photocatalytic performance under sunlike irradiation. The photocatalytic performance of Bi(2)WO(6) and Bi(2)WO(6)-TiO(2) was compared under different irradiation conditions and using increasing Rhodamine B concentration up to 25 ppm. After the photocatalytic analysis of both systems, the mineralization efficiency of the heterostructure appears significantly higher with respect to Bi(2)WO(6).

TiO2–SiO2 mixed oxides have been synthesised and modified by Ag and Pt deposition. Due to the effect of the silica on the mixed oxide, the prepared materials presented high surface areas and stabilised anatase as the only crystalline phase after calcination at 700 °C. Even using the same photodeposition experimental conditions, the yield for metal deposition depended highly on the metal considered, being much lower for Ag deposition. XPS studies permitted to estimate metal dispersion and oxidation state of the different samples, being both factors of high importance regarding photocatalytic improvement by metal deposition.

6 páginas, 2 figuras, 2 tablas., Flavonoids are polyphenols widely distributed in fruits and vegetables, and have been shown to be good antioxidants in different models. However, studies undertaken with the aim of predetermining the antioxidant power of a given food on the basis of its flavonoid content have, in most cases, failed due to differences between the theoretical and the calculated antioxidant power of that given product. In the present work, the antioxidant activity of eleven flavonoids (cyanidin-3-O-glucoside, malvidin-3-O-glucoside, delphinidin-3-O-glucoside, peonidin-3-O-glucoside, pelargonidin-3-O-glucoside, catechin, epicatechin, kaempferol, myricetin, quercetin and quercetin-3-β-glucoside) was measured by two different in vitro tests: DPPH radical scavenging activity and ferric reducing antioxidant power (FRAP). In order to evaluate the effect of flavonoid interactions on their antioxidant power we compared the capacity of individual flavonoids with that obtained by mixing them with another flavonoid. The majority of DPPH scavenging activities in these combinations promoted antagonistic effects, except for some synergistic interactions such as kaempferol paired with myricetin. In the FRAP assay, the interaction between epicatechin and quercetin-3-β-glucoside showed the highest synergistic effect, whereas myricetin with quercetin resulted in an antagonistic effect. It can be concluded, therefore, that there are synergistic and antagonistic interactions between flavonoids that may explain the results obtained when measuring the antioxidant effect of whole food extracts. The present results may also assist in the future design of functional foods or ingredients based on their antioxidant activity., This work was supported by the Spanish Ministry of Science and Innovation (AGL2006-05453) and the Comunidad Autónoma de Madrid (CCG07-CSIC/AGR-1762). M. Hidalgo wishes to thank CSIC, for a JAE predoctoral fellowship (JAEPre094).

TiO2 materials were prepared by sol–gel method and then impregnated with sulfuric acid and calcined using different temperatures and atmosphere (air and nitrogen). Systematic variation of these two experimental parameters makes possible to modulate the amount of surface sulfur from the impregnation procedure. The best photocatalyst for liquid phenol degradation was obtained after calcination at 700 °C in air, while gas toluene degradation optimum performance is obtained by calcination at 700 °C in nitrogen from 500 °C. Structural analysis of these materials by XRD, micro-Raman spectroscopy and FE-SEM shows that once calcined at 700 °C the material was a well-crystallized, high surface area anatase structure in all cases. The surface characterization by FTIR and XPS confirms the presence of a higher amount of sulfur species and acidic OH groups in samples partially calcined in nitrogen, and a low XPS O/Ti-atomic ratio with the O 1s peak shifted to higher binding energies (1.8 vs. 2 ± 0.1 and 530.4 eV vs. 529.8 eV, respectively, against the reference materials) for samples calcined at 700 °C, temperature at which most of sulfate species have been evolved. The paper presents an attempt to correlate the contribution of the observed structural defects within the anatase sub-surface layers and surface acidity to the different photoactivity behaviour exhibited for phenol liquid phase and toluene gas phase photodegradation.

ZnO nanoparticles have been prepared by amine template assisted sol–gel precipitation and further hydrothermal treatment. We have investigated the effect of different pH values achieved by means of triethylamine (TEA) addition in the final surface and structural properties. Two sets of samples were obtained after thermal treatment, one with no hydrothermal pre-treatment and a second hydrothermally pre-treated. Surprisingly the precipitate obtained after the amine addition also exhibits good photocatalytic properties. It has been stated that calcination treatment leads in both sets of samples to a significant improvement in the photocatalytic properties of the studied systems. Therefore, interesting comparison has been performed between hydrothermal pre-treated and direct thermal treated samples. Surface and morphological features notably differ from ZnO prepared using different synthetic route. Wide surface and structural characterization of the samples have been carried out, and correlations with precipitation pH are pointed out from this characterization. In all cases, the amine templated ZnO obtained exhibit high conversion values for phenol photo-oxidation reaction. Further calcination treatment in all of the studied samples clearly leads to photocatalytic conversions higher than that exhibited by TiO2 Degussa P25. This fact is even more significant if we consider that hydrothermally and calcined ZnO exhibit almost null surface area values, leading to a startling intrinsic photoactivity. The structural excellence (crystallinity, lack of defects, crystallite size, etc.) of such systems is clearly responsible for their high photoactivity values. # 2008 Elsevier B.V. All rights reserved.

An important improvement of the photocatalytic activity of sol–gel prepared TiO2 has been achieved by sulphate pre-treatment, calcination at high temperature and further platinisation of the samples. The presence of sulphuric acid clearly stabilised TiO2 surface area against sintering, maintaining at the same time anatase phase until higher calcination temperatures than in non-sulphated samples. Platinisation of the samples with different nominal amounts of platinum (from 0.5 to 2.5 wt%) was performed and the influence of sulphate treatment on the dispersion and deposit size of platinum on the TiO2 surface was studied. Characterisation results and photocatalytic activity of these catalysts were compared with those of unmodified TiO2. Simultaneously sulphated and platinised TiO2 samples were highly active for phenol degradation, used as model reaction for the photocatalytic studies, having higher activities than only platinised or only sulphated samples. The activity of these samples were several orders of magnitude higher than that of the commercial TiO2 Degussa P25 (platinised or unmodified) as well, with independence of the nominal amount of platinum of the samples. A wide characterisation of the samples was performed and correlations between characterisation results and activity properties are reported.

Some parameters that may have an influence on the photocatalytic activity of TiO 2 modified by platinisation have been studied, including structural composition, source of TiO 2 or platinum-deposit size. A wide number of different TiO 2 was used for the study: commercial TiO 2 Degussa P25, Hombikat UV-100 and Rutile Aldrich as well as TiO 2 prepared by sol–gel method in our laboratory. Platinisation was performed in all cases over the different TiO 2 by photodeposition of platinum from hexachloroplatinic(IV) acid (H 2 PtCl 6 ), depositing an amount of 0.5% Pt (weight total to TiO 2 ) and using isopropanol as reducting agent under N 2 atmosphere. All samples were widely characterised: surface area and porosity, phase composition and crystallite size, UV–vis absorption properties, etc. The study of the platinum deposit sizes was attempted by transmission electron microscopy (TEM). The enhancing or detrimental effect of the platinum deposits on the photocatalytic activity of the different TiO 2 for phenol oxidation was studied in correlation with the results of structural and surface characterisation.

The local zirconium and iron arrangements of the iron-doped ZrO2-TiO2 system, prepared by sol–gel impregnation method, were studied by EXAFS spectroscopy. Only a tetragonal ZrO2 structure is located on TiO2 surface. For the iron-doped ZrO2-TiO2 system, the presence of the Fe-O-Fe species as well as and Fe-O-Zr species located on the surface/pre-surface region are shown; it seems that iron is heterogeneously distributed, forming small iron oxide nanoclusters and Fex/ZrO2 (tetragonal) spots at the catalyst surface. The photocatalytic activity of the un-doped and iron-doped binary system ZrO2-TiO2 was investigated in two kind of photoreactions: the salicylic acid photooxidation and the photocatalytic reduction of Cr(VI). Different photocatalytic behaviour has been found for the un-doped and iron-doped ZrO2-TiO2 systems which have been explained in terms of the EXAFS study. This study represents an example of attempt to prepare a new potential photoactive mixed oxide system, containing two ions (Ti4+ and Zr4+) with good photocatalytic activity if it is compared with commercial TiO2 (Degusssa P25) calcined at 600 °C.