Health-related physical fitness in Brazilian adolescents from a small town of German colonization

Objective: To identify the health-related physical fitness profile of Brazilian adolescents (10–17 years) living in a small town of German colonization and to describe the prevalence of those with low levels of physical fitness according to sex and age. Method: This is a school-based cross-sectional epidemiological study conducted with all adolescents (10–17 years) enrolled in five public schools of São Bonifácio, Brazil. The study included 277 adolescents (145 boys and 132 girls). The FITNESSGRAM® test battery was applied for the assessment of percent body fat, flexibility, muscle strength/endurance and cardiorespiratory fitness. Results: Higher mean values of percent body fat and flexibility (p < 0.01) were found in girls; boys showed higher means (p < 0.01) for pull-up and cardiorespiratory fitness tests. The prevalence of adolescents with low levels of physical fitness was high for percent body fat (boys: 29.3%, girls: 31.8%, p = 0.75), flexibility (boys: 26.9%, girls: 54.5%, p < 0.01), muscle strength/endurance (curl-up: 37.9% of boys and 45.5% of girls, p = 0.25; modified pull-up: 47.6% of boys and 54.5% of girls, p = 0.30) and cardiorespiratory fitness (boys: 28.0%, girls: 36.9%, p = 0.15). As for the overall physical fitness, 75.7% of boys and 88.9% of girls did not meet the minimum recommended values (p = 0.01). Conclusion: Effective intervention programs are necessary to promote changes in the health-related physical fitness profile of adolescents from São Bonifácio, Brazil

Use of mechanically-activated kaolin to replace ball clay in engobe for a ceramic tile

Abstract Ceramic engobe is an intermediate layer between the substrate and the glaze of a ceramic tile. It is basically composed by plastic material, clays, and non-plastic material, feldspar and frit. Light-colored clays with good plasticity and low-fire temperature are used in ceramic engobe formulations, typically ball clays. However, these clays contain different accessory minerals, which can adversely affect the opacity and the whiteness. The use of washed kaolin, with a lower content of accessory minerals, tends to lead to higher opacity and whiteness. In addition, its mechanical activation can increase the plasticity, allowing its use as a replacement for ball clay. The aim of this study was to investigate the effect of the use of mechanically-activated kaolin to replace ball clay in an engobe employed in the production of ceramic tiles. Samples of kaolin were activated by high energy mill (1 and 4 h, at 500 rpm) and characterized by surface area and particle size measurements, crystallography, infrared spectroscopy and differential scanning calorimetry. Cylindrical specimens of four ceramic engobe formulations were submitted to splitting tensile strength and bulk density tests. The specimens were fired in a laboratory kiln and characterized through the determination of water absorption, bulk density, relative density and by reflectance spectrophotometry. Crystallographic analysis with Rietveld refinement and microstructural analysis by scanning electron microscopy were also carried out. After the high energy milling, the kaolin had less crystallinity and the specific surface area increased from 4.6 to 46.1 m2/g. The use of mechanically-activated kaolin as a replacement for ball clay in a ceramic engobe increased the mechanical strength, crystalline phase content and whiteness