When does obesity begin in northern Iranian children?

Background: Identifying the onset of obesity in children can be helpful to design the prevention programs for obesity and its complications. The aim of this study was to evaluate the onset of obesity in children. Methods: This cross-sectional study was conducted on the first grade of primary school children in Sari (urban areas) (Mazandaran Province, Iran) in 2014. The names and contact information of the first grade of primary school children (6–7 years old) were obtained through referring to Sari Health Center (Schools Health Unit). The onset of obesity was identified and recorded based on a body mass index (BMI) higher than 95 (for age and gender) and the weight/age and height/age Centers for Disease Control and Prevention (CDC) growth charts which were available in the child health records. Results: There were 127 obese children (71 boys, 56 girls) in the current study. The mean weight, height and BMI of children were 32.63±4.918 (kg), 123.02±5.166 (cm) and 21.52±2.369 (kg/m2), respectively. Furthermore the chance of obesity increased as the child grew up and there was an upward trend from 3 to 6 years old. Conclusions: According to the results the obesity frequency remains high; thus, it is important to pay special attention toward children's weight gain during this period even if it is not within the overweight/obesity range

Sol-gel synthesis of (Ca-Ba)TiO3 nanoparticles for bone tissue engineering

Piezoelectric materials are the group of smart materials which have been recently developed for biomedical applications, such as bone tissue engineering. These materials could provide electrical signals with no external source power making them effective for bone remodeling. Between various types of materials, BaTiO3 and CaTiO3 are nontoxic piezoelectric ceramics, which recently have been introduced for bone tissue engineering. It is expected that, the combination of these two ceramics could provide suitable piezoelectricity, bioactivity and biocompatibility for bone tissue engineering applications. The aim of this research is to synthesize (BaxCa1-x)TiO3 (x= 0, 0.6, 0.8, 0.9 and 1) nanopowder using sol-gel method. Moreover, the incorporation of Ca+2 ions in the structure of (BaxCa1-x)TiO3 nanoparticles was chemically, structurally and biologically studied. X-ray diffraction (XRD) and scanning electron microscopy (SEM) studies confirmed the role of substituted Ca content on the chemical properties and morphology of particles. Indeed, increasing the amounts of Ca+2 ions resulted in the reduced crystallite size. While incorporation of more than 20 at.% Ca resulted in the formation of a biphasic structure, monophasic solid solution without any secondary phase was detected at less Ca content. Moreover, SEM images revealed that Ca substitution reduced particle size from 70.5 ±12 nm to 52.4 ±9 nm, while the morphology of synthesized powders did not significacntly change. Furthermore, incorporation of upon 10 at.% Ca content within (BaxCa1-x)TiO3 significantly promoted MG63 proliferation compared to pure CaTiO3

Answers and Solutions

Answers and solutions to the puzzles in this issue

Physics-driven discovery and bandgap engineering of hybrid perovskites

The unique aspect of the hybrid perovskites is their tunability, allowing to engineer the bandgap via substitution. From application viewpoint, this allows creation of the tandem cells between perovskites and silicon, or two or more perovskites, with associated increase of efficiency beyond single-junction Schokley-Queisser limit. However, the concentration dependence of optical bandgap in the hybrid perovskite solid solutions can be non-linear and even non-monotonic, as determined by the band alignments between endmembers, presence of the defect states and Urbach tails, and phase separation. Exploring new compositions brings forth the joint problem of the discovery of the composition with the desired band gap, and establishing the physical model of the band gap concentration dependence. Here we report the development of the experimental workflow based on structured Gaussian Process (sGP) models and custom sGP (c-sGP) that allow the joint discovery of the experimental behavior and the underpinning physical model. This approach is verified with simulated data sets with known ground truth, and was found to accelerate the discovery of experimental behavior and the underlying physical model. The d/c-sGP approach utilizes a few calculated thin film bandgap data points to guide targeted explorations, minimizing the number of thin film preparations. Through iterative exploration, we demonstrate that the c-sGP algorithm that combined 5 bandgap models converges rapidly, revealing a relationship in the bandgap diagram of MA1-xGAxPb(I1-xBrx)3. This approach offers a promising method for efficiently understanding the physical model of band gap concentration dependence in the binary systems, this method can also be extended to ternary or higher dimensional systems