NOVAS IDADES U-Pb EM ZIRCÃO POR LA-ICP-MS DE METAGRANITOIDES DA ZONA DE INTERFERÊNCIA ENTRE A FAIXA BRASÍLIA SUL E A FAIXA RIBEIRA CENTRAL, NA REGIÃO SUL DO ESTADO DO RIO DE JANEIRO, BRASIL: New U-Pb Zircon Ages by LA-ICP-MS of Metagranitoids of Interference Zone between the Southern Brasília Belt and the Central Ribeira Belt, in South Region of Rio de Janeiro State, Brazil

In the towns of Resende and Itatiaia, south of Rio de Janeiro State, there are magmatic rock bodies traditionally inserted in the geotectonic context of the Ribeira belt. More recently, other works relate the region to the Interference Zone between the Brasília and Ribeira belts. Contributing to discussions about these interpretations, four metagranitoid bodies were selected for U-Pb analyses of zircon (LA-ICP-MS): a) Córrego das Cruzes, granodioritic inequigranular K-feldspar-biotite gneiss, crystallization and metamorphic ages of 1690±8.6Ma and 606±6.6Ma respectively; b) Engenheiro Passos, megaporphyritic hornblende-biotite metagranitoid, crystallization and metamorphic ages of 652.2±3.6Ma and 621.1±3.7Ma respectively; c) Marimbondo, hololeucocratic metagranite, crystallization and metamorphic ages of 605±2.4Ma and 585±4.8Ma respectively; d) Pedra Selada, granitic to granodioritic porphyritic (hornblende)-biotite metagranitoid, crystallization age of 590.7±1.5Ma. The oldest metagranitoid presents a crystallization age compatible with extensional events, however, this body is still poorly studied. The other bodies present Neoproterozoic crystallization ages correlated to different stages of the Brasília belt: pre-collisional, late-collisional and post-collisional, respectively. The metamorphic ages between 621-605Ma coincide with metamorphism related to the Brasília belt, whereas 585Ma would be associated with Ribeira belt metamorphism. These data corroborate interpretations that place the area in the Interference Zone between the Brasília and Ribeira belts.Nos municípios de Resende e Itatiaia, sul do Rio de Janeiro, ocorrem corpos de rochas magmáticas tradicionalmente inseridos no contexto geotectônico da Faixa Ribeira. Mais recentemente, outros trabalhos relacionam esta região à Zona de Interferência entre as faixas Brasília e Ribeira. Para contribuir com as discussões sobre estas interpretações foram selecionados quatro corpos de metagranitoides para análises U-Pb em zircão (LA-ICP-MS): a) Córrego das Cruzes, K-feldspato-biotita gnaisse inequigranular granodiorítico, com idade de cristalização 1.690±8,6Ma e de metamorfismo 606±6,6Ma; b) Engenheiro Passos, hornblenda-biotita metagranitoide megaporfirítico, com idade de cristalização 652,2±3,6Ma e de metamorfismo 621,1±3,7Ma; c) Marimbondo, metagranito hololeucocrático, com idade de cristalização 605±2,4Ma e de metamorfismo 585±4,8Ma; d) Pedra Selada, (hornblenda)-biotita metagranitoide porfirítico, granítico-granodiorítico, com idade de cristalização 590,7±1,5Ma. O mais antigo apresenta idade de cristalização compatível com eventos extensionais, entretanto este corpo ainda é pouco estudado. Os demais corpos apresentam idades de cristalização neoproterozoicas correlacionadas a distintos estágios da Faixa Brasília: pré-colisional, tardi-colisional e pós-colisional, respectivamente. As idades de metamorfismo entre 621-605Ma coincidem com metamorfismo relacionado à Faixa Brasília, enquanto a idade de 585Ma estaria associada a metamorfismo da Faixa Ribeira. Estes dados corroboram interpretações que inserem a área na Zona de Interferências entre as Faixas Brasília e Ribeira

Tangram: a contemporaneidade e conexões matemáticas desse jogo milenar

A partilha de experiências pedagógicas deve ser uma preocupação de todos os professores. Neste sentido, apresenta-se um relato de uma atividade realizada com alunos do 6º ano do Ensino Fundamental no Colégio Pedro II. Procuramos elucidar de forma clara nossa proposta pedagógica para que outros colegas possam, assim como nós, propor atividades experimentais para a construção e fixação de conceitos. Usando o jogo como ponto de partida e tendo como preocupação conectar dois temas fundamentais deste grau de ensino da educação básica: geometria e números, conseguimos aliar o lúdico à construção de conhecimento. A atividade foi realizada em duas aulas de 90min, cada, em três momentos: no primeiro, os alunos construíram um Tangram, efetuando dobraduras em uma folha A4; no segundo momento, os alunos foram convidados a refletir e a responder a várias questões que conectam as noções de área e de fração, recorrendo para isso às diferentes peças do Tangram e variando a unidade de área; no terceiro momento, os alunos participaram, em grupo, numa gincana na quadra de esportes. Relataremos as dificuldades, os questionamentos e os resultados obtidos, entre os quais, a constatação de que os alunos participando de atividades que aliam o lúdico à aquisição de conhecimento se tornam mais participativos e consolidam os conceitos de modo efetivo. Mostraremos imagens sobre a aplicação dos diversos momentos da atividade, ressaltando o fato de uma atividade desta natureza ser de enorme importância para o desenvolvimento de várias das inteligências múltiplas, segundo a classificação de Gardner

Consumption of High-Polyphenol Dark Chocolate Improves Endothelial Function in Individuals with Stage 1 Hypertension and Excess Body Weight

Background. Hypertension and excess body weight are important risk factors for endothelial dysfunction. Recent evidence suggests that high-polyphenol dark chocolate improves endothelial function and lowers blood pressure. This study aimed to evaluate the association of chocolate 70% cocoa intake with metabolic profile, oxidative stress, inflammation, blood pressure, and endothelial function in stage 1 hypertensives with excess body weight. Methods. Intervention clinical trial includes 22 stage 1 hypertensives without previous antihypertensive treatment, aged 18 to 60 years and presents a body mass index between 25.0 and 34.9 kg/m2. All participants were instructed to consume 50 g of chocolate 70% cocoa/day (2135 mg polyphenols) for 4 weeks. Endothelial function was evaluated by peripheral artery tonometry using Endo-PAT 2000 (Itamar Medical). Results. Twenty participants (10 men) completed the study. Comparison of pre-post intervention revealed that (1) there were no significant changes in anthropometric parameters, percentage body fat, glucose metabolism, lipid profile, biomarkers of inflammation, adhesion molecules, oxidized LDL, and blood pressure; (2) the assessment of endothelial function through the reactive hyperemia index showed a significant increase: 1.94 ± 0.18 to 2.22 ± 0.08, P=0.01. Conclusion.In individuals with stage 1 hypertension and excess body weight, high-polyphenol dark chocolate improves endothelial function

Consumption of High-Polyphenol Dark Chocolate Improves Endothelial Function in Individuals with Stage 1 Hypertension and Excess Body Weight

Background. Hypertension and excess body weight are important risk factors for endothelial dysfunction. Recent evidence suggests that high-polyphenol dark chocolate improves endothelial function and lowers blood pressure. This study aimed to evaluate the association of chocolate 70% cocoa intake with metabolic profile, oxidative stress, inflammation, blood pressure, and endothelial function in stage 1 hypertensives with excess body weight. Methods. Intervention clinical trial includes 22 stage 1 hypertensives without previous antihypertensive treatment, aged 18 to 60 years and presents a body mass index between 25.0 and 34.9 kg/m2. All participants were instructed to consume 50 g of chocolate 70% cocoa/day (2135 mg polyphenols) for 4 weeks. Endothelial function was evaluated by peripheral artery tonometry using Endo-PAT 2000 (Itamar Medical). Results. Twenty participants (10 men) completed the study. Comparison of pre-post intervention revealed that (1) there were no significant changes in anthropometric parameters, percentage body fat, glucose metabolism, lipid profile, biomarkers of inflammation, adhesion molecules, oxidized LDL, and blood pressure; (2) the assessment of endothelial function through the reactive hyperemia index showed a significant increase: 1.94 ± 0.18 to 2.22 ± 0.08, P=0.01. Conclusion.In individuals with stage 1 hypertension and excess body weight, high-polyphenol dark chocolate improves endothelial function

The use of aqueous potassium dichloroiodate for the synthesis of ureas

AbstractWe report a straightforward and efficient reaction protocol for the syntheses of substituted ureas via treatment of thioureas with aqueous potassium dichloroiodate (KICl2). By tuning the reaction condition, thioureas bearing activated N-aryl substituents may undergo either selective oxidation or sequential oxidation and iodination, forming iodoaryl ureas in the latter case

Accurel MP 1000 as a support for the immobilization of lipase from Burkholderia cepacia: Application to the kinetic resolution of myo-inositol derivatives

Lipase from Burkholderia cepacia (PS) has been immobilized on Accurel MP 1000, and their performance has been compared to that of the most widely used immobilized commercial preparation of this enzyme. The maximum loading was 18 mg protein/g support, and its thermal and solvent stability was much higher than that of the commercial. PS preparations were used in hydrolysis of triacetin and methyl mandelate, in the esterification of oleic acid and ethanol and in the kinetic resolution of 1,3,4-tri-O-benzyl-myo-inositol (DL-1) using vinylacetate as activated acyl donor. For all reactions studied, PS on Accurel was more active than PS-IM. The conversion in the kinetic resolution of racemic DL-1 was optimized using response surface methodology. Optimal conditions were determined to be 2.0 mg/mL of substrate, temperature of 40 °C, 2.0 mL of vinyl acetate and without water addition. Under these conditions, maximum loaded Accurel-PS preparation permitted to improve the activity in this kinetic resolution compared to the PS commercial preparation by a 55-fold factor, and compared to Novozym 435 (the most active described in literature for this reaction) by a 23-fold factor. The conversion attained was 49.9% ± 0.3 of conversion and ee of 99% after 24 h. The reusability studies showed maintenance of conversion and ee during eight cycles.We gratefully recognize the support from the MINECO of Spanish Government, by the grant CTQ2013-41507-R, and Brazilian FAPERJ, CNPq and CAPES for funding and/or fellowships, including a PVE project for R. Fernandez-Lafuente.Peer Reviewe

A novel N95 respirator with chitosan nanoparticles: mechanical, antiviral, microbiological and cytotoxicity evaluations

Abstract Background It is known that some sectors of hospitals have high bacteria and virus loads that can remain as aerosols in the air and represent a significant health threat for patients and mainly professionals that work in the place daily. Therefore, the need for a respirator able to improve the filtration barrier of N95 masks and even inactivating airborne virus and bacteria becomes apparent. Such a fact motivated the creation of a new N95 respirator which employs chitosan nanoparticles on its intermediate layer (SN95 + CNP). Results The average chitosan nanoparticle size obtained was 165.20 ± 35.00 nm, with a polydispersity index of 0.36 ± 0.03 and a zeta potential of 47.50 ± 1.70 mV. Mechanical tests demonstrate that the SN95 + CNP respirator is more resistant and meets the safety requisites of aerosol penetration, resistance to breath and flammability, presenting higher potential to filtrate microbial and viral particles when compared to conventional SN95 respirators. Furthermore, biological in vitro tests on bacteria, fungi and mammalian cell lines (HaCat, Vero E6 and CCL-81) corroborate the hypothesis that our SN95 + CNP respirator presents strong antimicrobial activity and is safe for human use. There was a reduction of 96.83% of the alphacoronavirus virus and 99% of H1N1 virus and MHV-3 betacoronavirus after 120 min of contact compared to the conventional respirator (SN95), demonstrating that SN95 + CNP have a relevant potential as personal protection equipment. Conclusions Due to chitosan nanotechnology, our novel N95 respirator presents improved mechanical, antimicrobial and antiviral characteristics