Abstract Atom-Transfer Radical Copolymerization (ATRP) of methyl methacrylate (MMA) and ethyl methacrylate (EMA) under different reaction conditions was conducted using Grubbs 1st ( 1) and 2nd (2) generation catalysts. Initially, the study focused on the reactivity of the catalysts in ATRP of EMA individually, then the syntheses of poly(MMA-co-EMA) were also conducted in different mixtures of monomers ([MMA]/[EMA] = 100/200 and [MMA]/[EMA] = 200/100). Conversion and semilogarithmic kinetic plots as a function of time were related to the different catalysts and reaction conditions. The values of Mn and PDI also changed when different catalysts were used in the presence of Al(OiPr)3, and more controlled polymerizations were achieved using 1. In the syntheses of poly(MMA)-co -(EMA), conversion of 60% was reached for both catalysts at different [MMA]/[EMA] ratios for 16 h; however, for shorter time, 4 h, better conversion values were obtained using 1 as catalyst for both [MMA]/[EMA] = 100/200 or 200/100.

RESUMO Estudo de caso único, de abordagem quanti-qualitativa que buscou analisar a inclusão digital de adolescentes em uma escola pública do Oeste de Minas Gerais. Coletaram-se dados a partir de um questionário; um ambiente virtual de aprendizado e diários de campo. Os dados quantitativos foram analisados por estatística descritiva. Já os dados qualitativos foram analisados a partir da Análise de Conteúdo. Constataram-se fragilidades na inclusão digital dos adolescentes estudados e diferenças comportamentais no uso do ambiente virtual de aprendizado. A linguagem foi coloquial, sintética e com erros. A interação foi incipiente, ocorrendo, eventualmente, o cyberbullying. O ambiente virtual foi subutilizado e constataram-se fragilidades no suporte da comunidade escolar para o acesso a tecnologia. Conclui-se que a inclusão digital dos adolescentes, visando o acesso à informação em saúde, no cenário estudado permanece como um desafio atual.

ABSTRACT A unique case study, of quantitative-qualitative approach, that sought to analyze the digital inclusion of adolescents in a public school in the West of Minas Gerais. Data were collected from a questionnaire; A virtual learning environment and registry of observations. Quantitative data were analyzed by descriptive statistics. The qualitative data were analyzed from the Content Analysis. There were weaknesses in the digital inclusion of the adolescents studied and behavioral differences in the use of the virtual learning environment. The language was colloquial, synthetic and with errors. The interaction was incipient, eventually occurring cyberbullying. The virtual environment was underutilized and fragilities were found in the support of the school community for access to technology. It is concluded that the digital inclusion of adolescents, aiming at access to health information, in the scenario studied remains a current challenge.

OBJETIVO: Avaliar a densidade mineral óssea (DMO) em adolescentes do sexo feminino de acordo com a idade cronológica (IC), idade óssea (IO) e desenvolvimento das mamas (M) e suas correlações com biomarcadores de remodelação óssea em plasma (BO). MÉTODOS: Este foi um estudo transversal prospectivo feito em 101 adolescentes saudáveis do sexo feminino com idade entre 10 e 20 anos. As variáveis estudadas foram: peso, altura, índice de massa corpórea (IMC), IC, IO, M, ingestão de cálcio, DMO e BO. A osteocalcina (OC), fosfatase alcalina óssea (BAP) e o telopeptídeo C terminal (S-CTx) foram os biomarcadores de remodelação óssea avaliados. A DMO foi obtida por absorciometria de raios-X de dupla energia (DXA). RESULTADOS: A DMO de coluna lombar, fêmur proximal e corpo total aumentou com a idade, e as respectivas médias observadas foram: IC1 = 0,631, 0.692, 0,798 g/cm2; IC2, 0,698, 0,763, 0,840 g/cm2; IC3, 0,865, 0,889, 0,972 g/cm2; IC4, 0,902, 0,922, 1,013 g/cm2; e IC5, 0,944, 0,929, 1,35 g/cm2. Observou-se diferença significativa entre 13 e 14 anos (IC3) ou quando as meninas estavam em M3 (0,709, 0,832, 0,867 g/cm2). Os valores dos BO apresentaram elevação entre 10 e 12 anos e quando as adolescentes estavam em M2-M3 (p < 0,001). Os valores das medianas dos BO diminuíram com o avançar da IO e M. CONCLUSÕES: Os BOs mostraram paralelismo com o pico de velocidade de crescimento e demonstraram correlação negativa com a DMO no sítios avaliados. O aumento da DMO e dos BOs foi observado em M3.

OBJECTIVE: To study bone mineral density (BMD) in adolescent females according to five groups of chronological age (CA), bone age (BA), and breast development stage (B), and to correlate these parameters with plasma bone biomarkers (BB). METHODS: This was a cross-sectional study performed in 101 healthy adolescent females between 10 and 20 years old. The study variables were: weight, height, body mass index (BMI), CA, B, BA, calcium intake, BMD, and BB. Osteocalcin (OC), bone alkaline phosphatase (BAP), and C-terminal telopeptide (S-CTx) were evaluated for BB. BMD was measured using dual energy X-ray absorptiometry (DXA). RESULTS: BMD in lumbar spine, proximal femur, and total body increased with age, and the respective observed averages were: in CA1 (10 years old), 0.631, 0.692, 0.798 g/cm2; in CA2 (11 to 12 years old), 0.698, 0.763, 0.840 g/cm2; in CA3 (13 to 14 years old), 0.865, 0.889, 0.972 g/cm2; in CA4 (15 to 16 years old), 0.902, 0.922, 1.013 g/cm2; and in CA5 (17 to 19 years old), 0.944, 0.929, 1.35 g/cm2. These results showed significant differences between 13 and 14 years of age (CA3) or when girls reached the B3 stage (0.709, 0.832, 0.867 g/cm2). The highest median concentrations of BB were between 10 and 12 years of age when adolescents were in the B2-B3 (p < 0.001). Median BB concentrations decreased in advanced BA and B. CONCLUSIONS: BB concentrations were positively correlated with the peak height velocity and negatively correlated with BMD in the study sites. Increased BMD and BB concentrations were observed in B3.