Flame-Retarding Properties of Injected and 3D-Printed Intumescent Bio-Based PLA Composites: The Influence of Brønsted and Lewis Acidity of Montmorillonite.

The influence of processing intumescent bio-based poly(lactic acid) (PLA) composites by injection and fused filament fabrication (FFF) was evaluated. A raw (ANa) and two acidic-activated (AH2 and AH5) montmorillonites were added to the intumescent formulation, composed by lignin and ammonium polyphosphate, in order to evaluate the influence of the strength and the nature (Brønsted or Lewis) of their acidic sites on the fire behavior of the composites. The thermal stability and the volatile thermal degradation products of the composites were assessed. The injected and 3D-printed composites were submitted to cone calorimeter (CC), limit oxygen index (LOI), and UL-94 flammability tests. A similar tendency was observed for the injected and 3D-printed samples. The high density of strong Lewis sites in AH2 showed to be detrimental to the fire-retarding properties. For the CC test, the addition of the intumescent composite reduced the peak of heat released (pHRR) in approximately 49% when compared to neat PLA, while the composites containing ANa and AH5 presented a reduction of at least 54%. However, the addition of AH2 caused a pHRR reduction of around 47%, close to the one of the composite without clay (49%). In the LOI tests, the composites containing ANa and AH5 achieved the best results: 39% and 35%, respectively, for the injected samples, and 35 and 38% for the 3D-printed samples. For the composite containing AH2 the LOI values were 34% and 32% for injected and 3D-printed samples, respectively. Overall, the best performance in the flammability tests was achieved by the composites containing clays with only weak and moderate strength acidic sites (ANa and AH5).

Synergistic Action of Montmorillonite with an Intumescent Formulation: The Impact of the Nature and the Strength of Acidic Sites on the Flame-Retardant Properties of Polypropylene Composites.

A raw montmorillonite (Mt) was submitted to different acidic activation times in order to investigate the influence of the strength and the nature (Brønsted and Lewis) of acidic sites on the synergistic action with an intumescent formulation (IF) composed of ammonium polyphosphate (APP) and pentaerythritol (PER) when incorporated into a polypropylene (PP) matrix. The acidity of the Mt samples was quantified by ammonia temperature-programmed desorption (TPD-NH3) and Fourier transform infrared spectroscopy (FTIR) with pyridine adsorption. The mineral clays were also characterized by X-ray fluorescence (XRF), X-ray diffraction (XRD), nitrogen adsorption analysis and particle size distribution. Thermogravimetric analysis (TGA), limit oxygen index (LOI) and UL-94 were performed to evaluate the flame-retardant properties and the thermal stability. The TGA results show that the final residue increased 2 to 3 fold in comparison to the values predicted theoretically. The flammability properties achieved a maximum for the system containing an excess of moderate-strength Brønsted sites relative to the Lewis ones, reaching 38% in the LOI test. This result suggests that the presence of these Brønsted acidic sites is important, as they take part in the esterification reaction between APP and PER which gives rise to the char formation. The FTIR-Pyr adsorption and flammability results indicate that both the nature and strength of the acidic sites influence the flame-retardant properties.

Hormone therapy after risk-reducing surgery in patients with BRCA1/BRCA2 mutation: evaluation of potential benefits and safety.

Women with mutations in the BRCA 1 and 2 genes are at increased risk for ovarian and breast cancer and therefore candidates for risk-reducing surgery, including salpingo-oophorectomy and mastectomy. Risk-reducing salpingo-oophorectomy (RRSO) is considered the most effective prophylactic measure for ovarian cancer prevention in this group of patients. This procedure involves loss of ovarian function and induced menopause. Estrogen therapy is the most effective treatment for controlling vasomotor symptoms and improving the quality of life of climacteric women. However, the potential hormonal stimulation of these tumors and the risk of breast cancer are a concern regarding the safety of hormone replacement therapy (HRT) in this population. This article aims to review the current evidence regarding the potential benefits and safety of HRT after RRSO.

Hormone therapy after risk-reducing surgery in patients with BRCA1/BRCA2 mutation: evaluation of potential benefits and safety

SUMMARY Women with mutations in the BRCA 1 and 2 genes are at increased risk for ovarian and breast cancer and therefore candidates for risk-reducing surgery, including salpingo-oophorectomy and mastectomy. Risk-reducing salpingo-oophorectomy (RRSO) is considered the most effective prophylactic measure for ovarian cancer prevention in this group of patients. This procedure involves loss of ovarian function and induced menopause. Estrogen therapy is the most effective treatment for controlling vasomotor symptoms and improving the quality of life of climacteric women. However, the potential hormonal stimulation of these tumors and the risk of breast cancer are a concern regarding the safety of hormone replacement therapy (HRT) in this population. This article aims to review the current evidence regarding the potential benefits and safety of HRT after RRSO.

RESUMO Mulheres portadoras de mutações nos genes BRCA 1 e 2 possuem risco aumentado para cânceres de ovário e mama e, portanto, são candidatas às cirurgias redutoras de risco, incluindo a salpingo-ooforectomia e a mastectomia. A salpingo-ooforectomia redutora de risco (SORR) é considerada a medida profilática mais efetiva para prevenção do câncer de ovário nesse grupo de pacientes. Esse procedimento implica a perda da função ovariana e menopausa induzida. A estrogenioterapia é o tratamento mais efetivo para o controle de sintomas vasomotores e melhora da qualidade de vida de mulheres no climatério. No entanto, a potencial estimulação hormonal desses tumores e o risco de câncer de mama constituem uma preocupação com a segurança da terapia hormonal (TH) nesta população. Este artigo tem como objetivo uma revisão das evidências atuais quanto aos benefícios potenciais e segurança da TH após SORR.

Panorama da Sífilis no município do norte brasileiro no período de 2013 a 2017 / Panorama general de la sífilis en el municipio del norte de Brasil de 2013 a 2017 / Overview of Syphilis in the northern Brazilian municipality from 2013 to 2017

Justificativas e Objetivos: A sífilis é a infecção bacteriana mais disseminada na população humana, sendo a principal forma de transmissão por contato sexual. Analisar os dados epidemiológico da população do município de Rio Branco ­ Acre ­ Brasil com diagnóstico positivo da Sífilis entre os anos de 2013 e 2017. Métodos: Trata-se de um estudo descritivo, do tipo transversal e abordagem quantitativa aplicado aos dados do Laboratório Central de Saúde Pública do Acre da população infectada com T. pallidum. Resultados: De um total de 5.239 pessoas infectadas com sífilis, 56,8% são do sexo feminino entre idade de 20 a 30 anos e autodeclaradas de cor parda. Além disso, 1006 gestantes, 43% das quais estavam na faixa de 11 a 20 anos e 37,5% estavam no segundo trimestre da gestação. Para os nascidos vivos, 107 crianças com sífilis congênita precoce foram diagnosticadas. Conclusão: As informações para a prevenção da infecção devem ser intensificadas principalmente as pessoas que estão desinformadas sobre a IST na cidade como os: adolescentes, idosos e populações indígenas afim de evitar a transmissão da sífilis.(AU)

Justifications and Objectives: Syphilis is the most widespread bacterial infection in the human population, being the main form of transmission through sexual contact. Analyze the epidemiological data of the population of the municipality of Rio Branco - Acre - Brazil with a positive diagnosis of Syphilis between the years 2013 and 2017. Methods: This is a descriptive, cross-sectional study with a quantitative approach applied to data from the Central Laboratory of Public Health in Acre of the population infected with T. pallidum. Results: Of a total of 5,239 people infected with syphilis, 56.8% are female between the ages of 20 and 30 years old and self-declared to be brown. In addition, 1006 pregnant women, 43% of whom were between 11 and 20 years old and 37.5% were in the second trimester of pregnancy. For live births, 107 children with early congenital syphilis were diagnosed. Conclusion: Information for the prevention of infection should be intensified, especially for people who are uninformed about STIs in the city, such as: adolescents, the elderly and indigenous populations in order to avoid syphilis transmission.(AU)

Justificación y objetivos: La sífilis es la infección bacteriana más extendida en la población humana, siendo la principal forma de transmisión a través del contacto sexual. Analice los datos epidemiológicos de la población del municipio de Rio Branco - Acre - Brasil con un diagnóstico positivo de sífilis entre los años 2013 y 2017. Métodos: Este es un estudio descriptivo, transversal con un enfoque cuantitativo aplicado a los datos del Laboratorio Central de Salud Pública en Acre de la población infectada con T. pallidum. Resultados: De un total de 5,239 personas infectadas con sífilis, el 56.8% son mujeres entre las edades de 20 y 30 años y se declaran marrones. Además, 1006 mujeres embarazadas, el 43% de las cuales tenían entre 11 y 20 años y el 37.5% estaban en el segundo trimestre del embarazo. Para los nacimientos vivos, se diagnosticaron 107 niños con sífilis congénita temprana. Conclusión: La información para la prevención de la infección debe intensificarse, especialmente para las personas que no están informadas sobre las ITS en la ciudad, como: adolescentes, ancianos y poblaciones indígenas para evitar la transmisión de la sífilis.(AU)

Microscopy as a tool to investigate the influence of ammonium polyphosphate particle size on the flame retardant properties of polymer composites.

The influence of ammonium polyphosphate (APP) particle size on the performance of an intumescent formulation and on the synergistic action of a series of montmorillonite samples with different d-spacings for the production of flame retardant composites was investigated. The polymer matrix employed was poly(ethylene-co-butyl acrylate), EBA 30, and the intumescent formulation consisted of APP and pentaerythritol (PER). After being processed, the composites were submitted to scanning electron microscopy (SEM), thermogravimetric analysis, heating microscopy, and limiting oxygen index tests. The results indicate that the greater interaction between the APP and PER molecules, caused by the increase of the contact area promoted by the reduction of the APP particle size, could favor the esterification reaction between APP423 and PER, allowing the formation of a greater amount of char precursors in shorter period of time. In addition, the montmorillonite d-spacings had a more pronounced influence on the clays synergistic action with the intumescent formulation containing the APP with smaller particle size. Microscopy has shown to be an important tool to investigate APP particle size effect on the fire retardancy. AFM results enabled the detection of nanometric particles in the sample containing the smallest particle size of APP. SEM micrographs showed that those nanometric particles were better dispersed in the matrix, interacting more effectively with the other components, a factor probably responsible for the superior fire retardancy results. Heating microscopy revealed that the material with smaller APP particle size did show some remaining structure at the temperature of 850°C.

Influence of Manufacturing Methods of Implant-Supported Crowns on External and Internal Marginal Fit: A Micro-CT Analysis.

AIM: To evaluate the influence of different manufacturing methods of single implant-supported metallic crowns on the internal and external marginal fit through computed microtomography. METHODS: Forty external hexagon implants were divided into 4 groups (n = 8), according to the manufacturing method: GC, conventional casting; GI, induction casting; GP, plasma casting; and GCAD, CAD/CAM machining. The crowns were attached to the implants with insertion torque of 30 N·cm. The external (vertical and horizontal) marginal fit and internal fit were assessed through computed microtomography. Internal and external marginal fit data (µm) were submitted to a one-way ANOVA and Tukey's test (α = .05). Qualitative evaluation of the images was conducted by using micro-CT. RESULTS: The statistical analysis revealed no significant difference between the groups for vertical misfit (P = 0.721). There was no significant difference (P > 0.05) for the internal and horizontal marginal misfit in the groups GC, GI, and GP, but it was found for the group GCAD (P ≤ 0.05). Qualitative analysis revealed that most of the samples of cast groups exhibited crowns underextension while the group GCAD showed overextension. CONCLUSIONS: The manufacturing method of the crowns influenced the accuracy of marginal fit between the prosthesis and implant. The best results were found for the crowns fabricated through CAD/CAM machining.

The role of uric acid in the insulin resistance in children and adolescents with obesity / O papel do ácido úrico na resistência insulínica em crianças e adolescentes com obesidade

Objective: To investigate the association between serum uric acid levels and insulin resistance in children and adolescents with obesity. Methods: Cross-sectional study with 245 children and adolescents (134 obese and 111 controls), aged 8-18 years. The anthropometric variables (weight, height and waist circumference), blood pressure and biochemical parameters were collected. The clinical characteristics of the groups were analyzed by t-test or chi-square test. To evaluate the association between uric acid levels and insulin resistance the Pearson's test and logistic regression were applied. Results: The prevalence of insulin resistance was 26.9%. The anthropometric variables, systolic and diastolic blood pressure and biochemical variables were significantly higher in the obese group (p<0.001), except for the high-density-lipoprotein cholesterol. There was a positive and significant correlation between anthropometric variables and uric acid with HOMA-IR in the obese and in the control groups, which was higher in the obese group and in the total sample. The logistic regression model that included age, gender and obesity, showed an odds ratio of uric acid as a variable associated with insulin resistance of 1.91 (95%CI 1.40-2.62; p<−0.001). Conclusions: The increase in serum uric acid showed a positive statistical correlation with insulin resistance and it is associated with and increased risk of insulin resistance in obese children and adolescents.

Objetivo: Investigar a associação entre os níveis séricos de ácido úrico e a resistência insulínica em crianças e adolescentes com obesidade. Métodos: Estudo transversal, com 245 crianças e adolescentes (134 obesos e 111 controles), entre oito e 18 anos. Foram coletadas variáveis antropométricas (peso, estatura e circunferência abdominal), pressão arterial e parâmetros bioquímicos. As características clínicas dos grupos foram analisadas pelo teste t ou pelo qui-quadrado. Para avaliar a associação entre os níveis de ácido úrico e a resistência insulínica usaram-se o teste de Pearson e regressão logística. A resistência insulínica foi a variável dependente no modelo de regressão. Resultados: A prevalência de resistência insulínica foi de 26,9%. As variáveis antropométricas, a pressão arterial sistólica e diastólica e as variáveis bioquímicas foram maiores no grupo obeso (p<0,001), exceto o colesterol de alta densidade. Foi observada correlação positiva e significativa entre as variáveis antropométricas e o ácido úrico com o HOMA-IR no grupo obeso e no controle. Essa foi maior no grupo obeso e na amostra total. No modelo de regressão logística que incluiu idade, sexo e obesidade, a odds ratio do ácido úrico como fator associado à resistência insulínica foi de 1,91 (IC95% 1,40-2,62; p<0,001). Conclusões: Observa-se que o aumento no nível sérico de ácido úrico apresenta correlação estatística positiva com a resistência insulínica e está associado à elevação no risco em crianças e adolescentes obesos.

[The role of uric acid in the insulin resistance in children and adolescents with obesity]. / O papel do ácido úrico na resistência insulínica em crianças e adolescentes com obesidade.

OBJECTIVE: To investigate the association between serum uric acid levels and insulin resistance in children and adolescents with obesity. METHODS: Cross-sectional study with 245 children and adolescents (134 obese and 111 controls), aged 8 to 18 years. The anthropometric variables (weight, height and waist circumference), blood pressure and biochemical parameters were collected. The clinical characteristics of the groups were analyzed by t-test or chi-square test. To evaluate the association between uric acid levels and insulin resistance the Pearson's test and logistic regression were applied. RESULTS: The prevalence of insulin resistance was 26.9%. The anthropometric variables, systolic and diastolic blood pressure and biochemical variables were significantly higher in the obese group (p<0.001), except for the high-density-lipoprotein cholesterol. There was a positive and significant correlation between anthropometric variables and uric acid with HOMA-IR in the obese and in the control groups, which was higher in the obese group and in the total sample. The logistic regression model that included age, gender and obesity, showed an odds ratio of uric acid as a variable associated with insulin resistance of 1.91 (95%CI 1.40 to 2.62; p<-0.001). CONCLUSIONS: The increase in serum uric acid showed a positive statistical correlation with insulin resistance and it is associated with and increased risk of insulin resistance in obese children and adolescents.

Frequência de fungos anemófilos em áreas críticas de unidade hospitalar de Aracaju, Sergipe, Brasil / Frequency of airborne fungus in critical areas at hospital unit of Aracaju, Sergipe, Brazil

Introdução: Além dos casos de alergia, muitos fungos oportunistas como dos gêneros Penicillium, Aspergillus, Cladosporium, Candida, Fusarium, são responsáveis por doenças desde otites, micotoxicoses, infecções urinárias, onicomicoses, infecções oculares até fungemias, fato este bastante preocupante para a clínica médica, pois tais micro-organismos estão dispersos abundantemente no meio ambiente. Objetivo: Verificar a frequência de fungos anemófilos em áreas críticas de unidade hospitalar. Método: As coletas foram realizadas pelo método de sedimentação gravitacional, em placas de Petri contendo ágar-Sabouraud-dextrose, nos setores do Centro Cirúrgico (CC), Centro de Terapia Infantil (CTI), Unidade de Terapia Intensiva (UTI) e Unidade de Terapia dos Queimados (UTQ). Resultados: Foram isolados do CC quatro gêneros de fungos, quatro da CTI, quatro da UTI e cinco da UTQ. Os gêneros detectados com maior frequência foram: Aspergillus spp (43%), Penicillum spp (12%), Fusarium spp (11%), Candidaspp (6%) e Curvularia spp (5%). A contaminação observada pode estar associada principalmente com a falta de metodologia de limpeza, com a ventilação artificial, e com o fluxo humano entre os setores.