Automatic determination of mercury in samples of environmental interest

An automatic flow injection (FI) system for the determination of mercury was developed using a commercial Gold vapour atomic absorption spectrophotometer (CVAAS). Control and data acquisition in the FI system was done with an IBM-PC 286 XI compatible microcomputer and a home-made interface, using software written in QuickBasic 4.5. Mercury content was determined by: sampling using a combination of four electromechanical three-way poly(tetrafluoroethylene) valves; separation of the dissolved reduced mercury in a gas/liquid separation cell using nitrogen as carrier, followed by amalgamation of the stripped metal on a gold wire column; after stripping the metal, cleaning the separation cell using vacuum, which was controlled by a three-way electromechanical valve; heating the gold wire column automatically to release the amalgamated mercury using an external nichrome wire coil; storing the output signals automatically to calculate the final mercury concentration, using commercially available software. The optimized system presents a detection limit of 5.3 ng l(-1) of mercury (30 pg absolute) using 5.7 ml (three injections of 1900 mu l of the sample) with an analytical frequency of six samples per hour and reproducibility of 5%. The procedure was used to determine mercury in fish, hair and natural water samples.18619319

Transversalidade e Tecnologias de Informação e Comunicação ensinando Química utilizando um ambiente virtual com tema gerador Água

Este projeto utiliza o Ambiente Virtual para o Estudo de Ciências (AVEC) veiculado através da internet, com a finalidade de ensinar Química a partir da Química Ambiental. Esta proposta visa desenvolver um modelo de construção do conhecimento para que o ensino de Química tenha uma melhor fundamentação teórica e que atenda a demandasocial por um ensino contextualizado e sintonizado com as necessidades tecnológicas atuais. O ambiente é baseado na metodologia ABC (Aprendizagem Baseada em Casos) eé composto de duas situações-problema relacionadas ao tema Água, sendo que a primeira está direcionada para professores e licenciandos de Química e a segunda para serem usados pelos professores com seus alunos no Ensino Médio. A situação problema enfatiza a escassez de água no planeta e sua poluição, ao mesmo tempo em que ensina Química. O AVEC-Química foi utilizado com licenciandos e professores de Química. O grupo de licenciandos participou ativamente se mostrando motivado e apresentando ao final uma avaliação positiva do ambiente com um aprendizado sobre os temas abordados que permitiram verificar a validade deste ambiente criado para o ensino de Química através da Química Ambiental

Automatic determination of mercury samples of environmental interest in

An automatic flow injection (FI) system for the determination of mercury was developed using a commercial cold vapour atomic absorption spectrophotometer (CVAAS). Control Pre-concentration procedures have a high level of reliability and applicability due to the lower detection limi

Fotocatálisis y seguridad alimentaria

Ponencia invitada a Congres

Uma experiência com alunos e professores de nível médio avaliando objetos de aprendizagem

Com a popularização da Internet, a quantidade de material digital disponível para ser utilizada aumenta cada vez mais, inclusive na educação. Muitas vezes, porém, os usuários não têm parâmetros para saber se a fonte que estão consultando é de qualidade ou não. Uma das formas de optar por um material é o mesmo já ter sido avaliado por um par, isto é, alguém do mesmo nível ou da mesma área. Este artigo relata o desafio de inserir alunos de nível médio no contexto do processo de avaliação de objetos de aprendizagem. Após a avaliação de 55 objetos nas áreas de Química, Física, Matemática e Biologia disponíveis no repositório do RIVED, verificou-se, por um lado, a pertinência de alunos avaliarem material que eles próprios irão utilizar, e, póoutro, a influência do nível de inclusão digital dos alunos no processo de avaliação

Utilizando mapas conceitual, de cenário e navegacional no apoio ao processo de desenvolvimento de objetos de aprendizagem

O desenvolvimento de objetos de aprendizagem (OA), quando não feitopelos próprios usuários, pode ser feito por equipes multidisciplinares, integrandopessoas de área técnica (computação), da área de domínio, pedagógica, entre outras.O processo de comunicação entre os integrantes da equipe bem como a própriaevolução do desenvolvimento do OA ao longo do ciclo de vida costuma ser registradade alguma forma. Entre as formas utilizadas encontra-se o conjunto de fases edocumentos propostos no âmbito do projeto RIVED (MEC). Este artigo discute aslimitações do processo proposto e propõe algumas inovações ao mesmo,incorporando mapas (conceitual, de cenários e navegacional), tornando o processogeral o suficiente para ser utilizado em outros âmbitos de desenvolvimento de OAs.Propõe, ainda, ummodelo ágil e colaborativo de forma a facilitar a integração entreas equipes e tornar o processo de desenvolvimento mais efetivo

Association between an oxidative balance score and mortality: a prospective analysis in the SUN cohort

We aimed to prospectively investigate the association of an overall oxidative balance score (OBS) with all-cause death and cause-specifc mortality among participants in the Seguimiento Universidad de Navarra (SUN) Study, a Mediterranean cohort of Spanish graduates. Methods Using baseline information on 12 a priori selected dietary and non-dietary lifestyle pro- and antioxidants exposures—vitamins C and E, β-carotenes, selenium, zinc, heme iron, polyphenols, total antioxidant capacity, body mass index, alcohol, smoking, and physical activity—we constructed an equally weighted OBS categorized into quartiles, with higher scores representing greater antioxidant balance. Cox proportional hazards models were ftted to evaluate the association between the OBS and mortality. Results A total of 18,561 participants (mean [SD] age, 38.5 [12.4] years; 40.8% males) were included in the analysis. During a median follow-up of 12.2 years (interquartile range 8.3–14.9), 421 deaths were identifed, including 80 deaths from cardiovascular disease (CVD), 215 from cancer, and 126 from other causes. After adjustment for potential confounders, the hazard ratios and 95% confdence interval (CIs) between the highest quartile (predominance of antioxidants) vs. the lowest quartile (reference category) were 0.35 (95% CI 0.22–0.54, P-trend<0.001) for all-cause mortality, 0.18 (95% CI 0.06–0.51, P-trend=0.001) for CVD mortality, 0.35 (95% CI 0.19–0.65, P-trend=0.002) for cancer mortality, and 0.45 (95% CI 0.20–1.02, P-trend=0.054) for other-cause mortality. Conclusion Our fndings suggest a strong inverse association between the OBS and all-cause, CVD, and cancer mortality. Individuals exposed to both antioxidant dietary and lifestyle factors may potentially experience the lowest mortality riskOpen Access funding provided thanks to the CRUE-CSIC agreement with Springer Nature. The SUN Project has received funding from the Spanish Government-Instituto de Salud Carlos III, and the European Regional Development Fund (FEDER) (RD 06/0045, CIBER-OBN, Grants PI10/02658, PI10/02293, PI13/00615, PI14/01668, PI14/01798, PI14/01764, PI17/01795, and G03/140), the Navarra Regional Government (27/2011, 45/2011, 122/2014), the Government Delegation for the National Drug Plan (2020/ 021) and the University of Navarra. Maria Soledad Hershey receives ERC traininggrant support (T42 OH008416

Propriedades redox da matéria orgânica isolada de material ultrafiltrado das águas do rio Paraíba do Sul

Previous studies indicated that free radicals control organic matter redox activities. In the present study, organic matter of an ultra-filtrated material collected from seven samples taken seasonally from the Paraiba do Sul River for two years were titrated with an oxidizer (I2) in an inert atmosphere. Standard formal potential values for the electrode MO Ox, MO Red ranged from 0.754 to 0.786 V at a 25 ºC temperature. Organic matter oxidation capacity (COx) per carbon mass varied according to pH values, and changes in COx were related to rainfall and river flow intensities

Complement and coagulation cascades activation is the main pathophysiological pathway in early-onset severe preeclampsia revealed by maternal proteomics

Preeclampsia is a pregnancy-specific multisystem disorder and a leading cause of maternal and perinatal morbidity and mortality. The exact pathogenesis of this multifactorial disease remains poorly defined. We applied proteomics analysis on maternal blood samples collected from 14 singleton pregnancies with early-onset severe preeclampsia and 6 uncomplicated pregnancies to investigate the pathophysiological pathways involved in this specific subgroup of preeclampsia. Maternal blood was drawn at diagnosis for cases and at matched gestational age for controls. LC-MS/MS proteomics analysis was conducted, and data were analyzed by multivariate and univariate statistical approaches with the identification of differential pathways by exploring the global human protein-protein interaction network. The unsupervised multivariate analysis (the principal component analysis) showed a clear difference between preeclamptic and uncomplicated pregnancies. The supervised multivariate analysis using orthogonal partial least square discriminant analysis resulted in a model with goodness of fit (R2X = 0.99, p < 0.001) and a strong predictive ability (Q2Y = 0.8, p < 0.001). By univariate analysis, we found 17 proteins statistically different after 5% FDR correction (q-value < 0.05). Pathway enrichment analysis revealed 5 significantly enriched pathways whereby the activation of the complement and coagulation cascades was on top (p = 3.17e-07). To validate these results, we assessed the deposits of C5b-9 complement complex and on endothelial cells that were exposed to activated plasma from an independent set of 4 cases of early-onset severe preeclampsia and 4 uncomplicated pregnancies. C5b-9 and Von Willbrand factor deposits were significantly higher in early-onset severe preeclampsia. Future studies are warranted to investigate potential therapeutic targets for early-onset severe preeclampsia within the complement and coagulation pathway

Effect of a Nutritional and Behavioral Intervention on Energy-Reduced Mediterranean Diet Adherence Among Patients With Metabolic Syndrome: Interim Analysis of the PREDIMED-Plus Randomized Clinical Trial

Key PointsQuestionWhat is the effect of a nutritional and behavioral intervention focused on encouraging an energy-reduced Mediterranean diet and physical activity on the dietary pattern of participants after 12 months? FindingsIn this preliminary analysis of an ongoing randomized clinical trial involving 6874 participants, an intervention focused on encouraging an energy-reduced Mediterranean diet and promoting physical activity, compared with advice to follow an energy-unrestricted Mediterranean diet, resulted in a significant increase in a measure of diet adherence, the 17-item energy-reduced Mediterranean diet score, at 12 months (4.7 points vs 2.5 points; score range, 0-17; minimal clinically important difference, 1 point). MeaningA nutritional and behavioral intervention focused on encouraging an energy-reduced Mediterranean diet and physical activity led to a significant improvement in a measure of diet adherence at 12 months. Further evaluation of the effects on long-term cardiovascular and other health outcomes is needed. ImportanceHigh-quality dietary patterns may help prevent chronic disease, but limited data exist from randomized trials about the effects of nutritional and behavioral interventions on dietary changes. ObjectiveTo assess the effect of a nutritional and physical activity education program on dietary quality. Design, Setting, and ParticipantsPreliminary exploratory interim analysis of an ongoing randomized trial. In 23 research centers in Spain, 6874 men and women aged 55 to 75 years with metabolic syndrome and no cardiovascular disease were enrolled in the trial between September 2013 and December 2016, with final data collection in March 2019. InterventionsParticipants were randomized to an intervention group that encouraged an energy-reduced Mediterranean diet, promoted physical activity, and provided behavioral support (n=3406) or to a control group that encouraged an energy-unrestricted Mediterranean diet (n=3468). All participants received allotments of extra-virgin olive oil (1 L/mo) and nuts (125 g/mo) for free. Main Outcomes and MeasuresThe primary outcome was 12-month change in adherence based on the energy-reduced Mediterranean diet (er-MedDiet) score (range, 0-17; higher scores indicate greater adherence; minimal clinically important difference, 1 point). ResultsAmong 6874 randomized participants (mean [SD] age, 65.0 [4.9] years; 3406 [52%] men), 6583 (96%) completed the 12-month follow-up and were included in the main analysis. The mean (SD) er-MedDiet score was 8.5 (2.6) at baseline and 13.2 (2.7) at 12 months in the intervention group (increase, 4.7 [95% CI, 4.6-4.8]) and 8.6 (2.7) at baseline and 11.1 (2.8) at 12 months in the control group (increase, 2.5 [95% CI, 2.3-2.6]) (between-group difference, 2.2 [95% CI, 2.1-2.4]; P<.001). Conclusions and RelevanceIn this preliminary analysis of an ongoing trial, an intervention that encouraged an energy-reduced Mediterranean diet and physical activity, compared with advice to follow an energy-unrestricted Mediterranean diet, resulted in a significantly greater increase in diet adherence after 12 months. Further evaluation of long-term cardiovascular effects is needed. Trial Registrationisrctn.com Identifier: ISRCTN89898870 This preliminary exploratory analysis of the ongoing PREDIMED-Plus randomized trial reports dietary adherence among Spanish community-dwelling participants with metabolic syndrome randomized to an energy-reduced Mediterranean diet, physical activity, and behavioral support vs an energy-unrestricted Mediterranean diet alone