565 research outputs found

    Fractionation of potentially toxic elements in urban soils from five European cities by means of a harmonised sequential extraction procedure

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    The revised (four-step) BCR sequential extraction procedure has been applied to fractionate the chromium, copper, iron, manganese, nickel, lead and zinc contents in urban soil samples from public-access areas in five European cities. A preliminary inter-laboratory comparison was conducted and showed that data obtained by different laboratories participating in the study were sufficiently harmonious for comparisons to be made between cities and land types (e.g. parks, roadside, riverbanks, etc.). Analyte recoveries by sequential extraction, with respect to direct aqua regia digestion, were generally acceptable (100 ± 15%). Iron, nickel and, at most sites, chromium were found mainly in association with the residual phase of the soil matrix. Copper was present in the reducible, oxidisable and residual fractions, whilst zinc was found in all four sequential extracts. Manganese was strongly associated with reducible material as, in some cities, was lead. This is of concern because high lead concentrations were present in some soils (>500 mg kg−1) and the potential exists for remobilisation under reducing conditions. As would be expected, extractable metal contents were generally highest in older, more heavily industrialised cities. Copper, lead and zinc showed marked (and often correlated) variations in concentrations between sites within the same city whereas manganese and, especially, iron, did not. No overall relationships were, however, found between analyte concentrations and land use, nor between analyte partitioning and land use

    Control of antioxidant efficiency of chlorogenates in emulsions: modulation of antioxidant interfacial concentrations

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    BACKGROUND Controlling the interfacial concentrations of antioxidants (AOs) in oil-in-water emulsions can be regarded as a unique approach for increasing the efficiency of AOs in inhibiting the oxidation of lipids. Classical methods to determine the AO distribution in binary systems cannot be employed and their distribution needs to be assessed in the intact emulsion. RESULTS We have employed a well-established kinetic method to determine the distribution of a homologous series of AOs derived of chlorogenic acid in olive oil-in-water emulsions and analyse the effects of AO hydrophobicity on their distributions and their efficiencies. Results indicate that variations in the efficiency of chlorogenates in emulsions are due to differences in their interfacial concentrations. Their interfacial concentrations AO(I) were much higher (20- to 150-fold) than their stoichiometric concentrations. On the other hand, their concentrations in the oil region were 1.5- to 0.1-fold. Results also show the complex effect of the oil-to-water ratio employed in the preparation of the emulsions on the (AO(I)) values. CONCLUSION Results highlight the key role of the interfacial region and of its composition (interfacial AO molarity, emulsifier concentration, oil-to-water ratio) in interpreting the efficiency of AOs in inhibiting lipid oxidation in emulsions. Thus, a careful modulation of these parameters is necessary to ensure optimum AO efficiency. (c) 2019 Society of Chemical IndustryFinancial support of the following institutions is acknowledged: FEDER (COMPETE) and FCT - Fundação para a Ciência e a Tecnologia (UID/QUI/50006/2013 - POCI-01-0145-FEDER-007265 and UID/QUI/00686/2016), Xunta de Galicia (10TAL314003PR and Programa de axudas a etapa posdoutoral), Ministerio de Educacion y Ciencia (CTQ2006-13969-BQU) and the Universities of Vigo and Porto. SL-B thanks Xunta de Galicia for a postdoctoral grant (POS-B/2016/012) and MC thanks FCT for the doctoral grant (SFRH/BD/100889/2014)

    Effects of the reactive moiety of phenolipids on their antioxidant efficiency in model emulsified systems

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    Our previous research was focused on the effects of hydrophobicity on the antioxidant (AO) efficiency of series of homologous antioxidants with the same reactive moieties. In this work we evaluate the antioxidant efficiency of hydrophobic phenolipids in 4:6 olive oil-in-water emulsions, with different phenolic moieties (derived from caffeic, 4-hydroxycinnamic, dihydrocaffeic acids, tyrosol and hydroxytyrosol), with alkyl chains of 8 and 16 carbons, and compare the antioxidant efficiency with that of the parent compounds. All catecholic phenolipids, in particular the C8 derivatives, have proven to be better antioxidants for the oxidative protection of emulsions than their parental compounds with octyl dihydrocafffeate being the most efficient (16-fold increase in relation to the control). To understand the importance of some factors on the antioxidant efficiency of compounds in emulsions, Pearson’s correlation analysis was carried out between antioxidant activity and the first anodic potential (Epa), reducing capacity (FRAP value), DPPH radical scavenging activity (EC50) and the concentration of antioxidants in each region of the emulsified system. Results confirm the importance of the effective concentration of AOs in the interfacial region (AOI) (ρ = 0.820) and of the Epa (ρ = −0.677) in predicting their antioxidant efficiency in olive oil-in-water emulsions.Research was funded by FCT/MCTES (UIDB/QUI/50006/2020; PTDC/OCE-ETA/32492/ 2017–POCI-01-0145-FEDER-032492; doctoral grant SFRH/BD/100889/2014), FCT and REQUIMTELAQV for a post-doc fellowship (PTDC/OCE- ETA/32492/2017), Xunta de Galicia (10TAL314003PR), the University of Vigo (postdoctoral grant-Talent Recruitment Program 2018) and the IACOBUS 2019 program. The manuscript was prepared during a sabbatical leave of C. B.-D., supported by the University of Vigo

    Gender differences in first-year college students’ academic expectations

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    Based on a multidimensional definition of academic expectations (AEs), the authors examine students’ AE component scores across countries and genders. Two samples (343 Portuguese and 358 Spanish students) completed the Academic Perceptions Questionnaire (APQ) six months after enrolling in their universities. Factorial invariance was ensured across countries and genders, allowing us to study AEs using the APQ for both genders and in both countries. No significant differences in factor means were found between countries, indicating that AEs are not an obstacle to student mobility. Gender differences were found in some AE factor means, Training for employment, Personal and social development, Student mobility, Political engagement and citizenship, and Social pressure, with males exhibiting higher scores. Because these differences are not supported by most literature in this domain, further studies are needed to clarify the causes of women’s lower expectations and, therefore, risk of adaptation difficulties

    Presentación del simposio

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    Admission to Higher Education (ES) presents students with different demands and opportunities, derived from their needs to meet educational goals, to regulate their learning, to manage study and leisure time, to participate on campus and in school. the classrooms and student representation, in a context of greater development and personal, social and emotional autonomy. Among the wide range of psychosocial and contextual variables that may be related to the experiences of this adaptation process, the academic expectations of the students in the first year of ES constitute the center of interest of this symposium. Just over half (57%) of full-time first-year students graduate in 4 years, sometimes being up to 6 years to get it. The percentage of students dropping out of school is mainly during the first year of study in the ES. Students who drop out without completing their studies are spending their time, money and Invested by the public sector in the educational process without, in the end, producing the desired benefits. That is why there is concern in recent years about the rates of academic graduation (Swail, 2004).La entrada en la Enseñanza Superior (ES) presenta a los estudiantes diversas exigencias y oportunidades, derivadas de sus necesidades de afrontamiento de metas educativas, de regulación de su aprendizaje, de gestión del tiempo de estudio y ocio, de participación en el campus y en las aulas y de representación estudiantil, en un contexto de mayor desarrollo y de autonomía tanto personal como social y emocional. De entre el amplio conjunto de variables psicosociales y contextuales que pueden estar relacionadas con las experiencias de este proceso de adaptación, las expectativas académicas de los estudiantes en el primer año de ES constituyen el centro de interés de este simposio. Poco más de la mitad (57 %) de los estudiantes de primer año a tiempo completo se gradúan en 4 años, siendo a veces necesarios hasta 6 años para conseguirlo. El porcentaje de abandono de los estudios se produce fundamentalmente durante el primer año de estudio en la ES. Los estudiantes que abandonan sin finalizar sus estudios suponen un gasto de su tiempo, de su dinero y delinvertido por el sector público en el proceso educativo sin que, a la postre, se produzcan los beneficios deseados. Es por eso que existe preocupación en los últimos años por las tasas de graduación académica (Swail, 2004)

    Is age a risk factor for liver disease and metabolic alterations in ataxia Telangiectasia patients?

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    Background: Ataxia telangiectasia (A-T) is a neurodegenerative disease that leads to mitochondrial dysfunction and oxidative stress. Insulin resistance (IR), type 2 diabetes and the risk for development of cardiovascular disease was recently associated as an extended phenotype of the disease. We aimed to assess IRliver involvementcarotid intima-media thickness (cIMT) and metabolic alterations associated to cardiovascular risk in A-T patients, and relate them with age. Results: Glucose metabolism alterations were found in 54.6% of the patients. Hepatic steatosis was diagnosed in 11/17 (64.7%) A-T patients. AST/ALT ratio > 1 was observed in 10/17 (58.8%). A strong positive correlation was observed between insulin sum concentrations with ALT (r = 0.782, p < 0.004) and age (r = 0.818, p = 0.002). Dyslipidemia was observed in 55.5% of the patients. The apolipoprotein (Apo-B)/ApoA-I ratio (r = 0.619p < 0.01), LDL/HDL-c (r = 0.490p < 0.05) and the Apo-B levels (r = 0.545p < 0.05) were positively correlated to cIMT. Conclusions: Metabolic disorders implicated in cardiovascular and liver diseases are frequently observed in adolescent A-T patients and those tend to get worse as they become older. Therefore, nutritional intervention and the use of drugs may be necessary.CAPES Foundation, Ministry of Education of Brazil, Brasilia DF, BrazilFed Univ São Paulo UNIFESP, Escola Paulista Med, Dept Pediat, Rua Otonis 725, BR-04025002 São Paulo, SP, BrazilABC Fdn FMABC, Fac Med ABC, Dept Morphol & Physiol, Santo Andre, SP, BrazilFed Univ São Paulo UNIFESP, Escola Paulista Med, Dept Diagnost Imaging, São Paulo, SP, BrazilSanta Casa São Paulo Sch Med Sci FCMSCSP, São Paulo, SP, BrazilFed Univ Alfenas UNIFAL, Sch Nutr, Alfenas, MG, BrazilFed Univ São Paulo UNIFESP, Escola Paulista Med, Dept Pediat, Rua Otonis 725, BR-04025002 São Paulo, SP, BrazilFed Univ São Paulo UNIFESP, Escola Paulista Med, Dept Diagnost Imaging, São Paulo, SP, BrazilWeb of Scienc

    Equivalencia factorial de las versiones en español y portugués de un cuestionario de expectativas académicas

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    Este estudio presenta los resultados de una investigación sobre expectativas académicas de estudiantes universitarios de primer año de Enseñanza Superior (ES) pertenecientes al norte de Portugal y noroeste de España. Su objetivo es replicar las propiedades psicométricas del instrumento utilizado obtenidas con una versión anterior del mismo. La muestra está integrada por 1.268 estudiantes de primer año de ES con edades comprendidas entre los 17 y 52 años (Mdn = 18, siendo de más de 23 años el 7.4%). Proceden de la región noroeste de España 413 estudiantes (Galicia, Universidad de Vigo) y 855 de la región norte de Portugal (Minho, Universidade do Minho). El 58.1% del total de la muestra son mujeres. Por ámbito de estudio, el 58.4% cursa titulaciones del ámbito científico-tecnológico y los demás del ámbito jurídico-social. Se aplicó el Cuestionario de Percepciones Académicas-Expectativas (CPA-E), estructurado en siete dimensiones: Formación para el empleo/carrera, Desarrollo personal y social, Movilidad estudiantil, Implicación político/ciudadana, Presión social, Calidad de formación e Interacción social. La invarianza del modelo factorial oblicuo del CPA-E fue testada con el LISREL 8.80 mediante el método bivariado latente normal y la estimación de máxima verosimilitud, con la corrección de Satorra y Bentler (1994). Todos los ítems representaron bien a sus respectivos factores y los factores mostraron una buena validez y fiabilidad para los países y el género. Se obtuvo, por tanto, invarianza factorial del modelo para los países y el género. Se asume una versión final del cuestionario común para España y Portugal, así como para mujeres y hombres.info:eu-repo/semantics/publishedVersio

    Factorial equivalence of the Spanish and Portuguese versions of a questionnaire of academic expectations

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    Este estudio presenta los resultados de una investigación sobre expectativas académicas de estudiantes universitarios de primer año de Enseñanza Superior (ES) pertenecientes al norte de Portugal y noroeste de España. Su objetivo es replicar las propiedades psicométricas del instrumento utilizado obtenidas con una versión anterior del mismo. La muestra está integrada por 1.268 estudiantes de primer año de ES con edades comprendidas entre los 17 y 52 años (Mdn = 18, siendo de más de 23 años el 7.4%). Proceden de la región noroeste de España 413 estudiantes (Galicia, Universidad de Vigo) y 855 de la región norte de Portugal (Minho, Universidade do Minho). El 58.1% del total de la muestra son mujeres. Por ámbito de estudio, el 58.4% cursa titulaciones del ámbito científico-tecnológico y los demás del ámbito jurídico-social. Se aplicó el Cuestionario de Percepciones Académicas-Expectativas (CPA-E), estructurado en siete dimensiones: Formación para el empleo/carrera, Desarrollo personal y social, Movilidad estudiantil, Implicación político/ciudadana, Presión social, Calidad de formación e Interacción social. La invarianza del modelo factorial oblicuo del CPA-E fue testada con el LISREL 8.80 mediante el método bivariado latente normal y la estimación de máxima verosimilitud, con la corrección de Satorra y Bentler (1994). Todos los ítems representaron bien a sus respectivos factores y los factores mostraron una buena validez y fiabilidad para los países y el género. Se obtuvo, por tanto, invarianza factorial del modelo para los países y el género. Se asume una versión final del cuestionario común para España y Portugal, así como para mujeres y hombres.We present the results of a study conducted with first-year students from the Euro- region of Galicia-North Portugal, with the aim of replicating the psychometric properties of the instrument as obtained from a prior version. Participants included 1268 first-year students with ages ranging from 17 to 52 years (Mdn = 18; 7.4% with ages above 23 years). Four-hundred and thirteen students are from the North Spanish region (Galicia, University of Minho) and 855 are from the North Portuguese region (Minho, University of Minho), and 58.1% of the students are women. Students are enrolled in scientific-technological courses (58.4%) and juridical-social studies. We administered the Academic Perceptions Questionnaire- Expectations (APQ-E), which is structured in seven dimensions: Training for career development, Personal and social development, Student mobility, Political engagement and citizenship, Social pressure, Training quality, and Social interaction. The invariance of the factorial model of the APQ-E was tested with LISREL 8.80, based on a bivariate latent model and maximum likelihood estimation, with Satorra and Bentler correction (1994). All items contributed to the representation of the factors, and the factors showed good validity and reliability for country and gender. Therefore, we obtained factorial invariance of the measurement model for country and gender. We present the final version of the common questionnaire for Portugal and Spain, and for women and men
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