Topological phase transformations and intrinsic size effects in ferroelectric nanoparticles.

Composite materials comprised of ferroelectric nanoparticles in a dielectric matrix are being actively investigated for a variety of functional properties attractive for a wide range of novel electronic and energy harvesting devices. However, the dependence of these functionalities on shapes, sizes, orientation and mutual arrangement of ferroelectric particles is currently not fully understood. In this study, we utilize a time-dependent Ginzburg-Landau approach combined with coupled-physics finite-element-method based simulations to elucidate the behavior of polarization in isolated spherical PbTiO or BaTiO nanoparticles embedded in a dielectric medium, including air.

Racial/ethnic differences in clinical and biochemical type 2 diabetes mellitus risk factors in children.

Objective: To examine whether periadolescent children demonstrate the significant racial/ethnic differences in body fatness relative to BMI and in the prevalence and relationship of body composition to risk factors for type 2 diabetes (T2DM) as in adults.

Design And Methods: Family history of obesity and T2DM, anthropometry, insulin sensitivity and secretory capacity, lipids, and cytokines (IL-6, CRP, TNF-α, and adiponectin) were examined in a cohort of 994 middle school students (47% male, 53%, female; 12% African American, 14% East Asian, 13% South Asian, 9% Caucasian, 44% Hispanic, and 8% other).

Results: Fractional body fat content was significantly greater at any BMI among South Asians.

Retinol binding protein 4 is associated with adiposity-related co-morbidity risk factors in children.

Objective: In adults, elevated levels of retinol binding protein 4 (RBP4) have been associated with biochemical markers of adiposity-related co-morbidities including insulin resistance, dyslipidemia, hypertension, and abdominal obesity. This study examined the relationship between RBP4 and risk factors for co-morbidities of adiposity in a population of ethnically diverse children in early- to mid-adolescence in the public school system of New York City.

Materials/methods: We analyzed anthropometric (body mass index, % body fat, waist circumference), metabolic (lipids, glucose), and inflammatory (TNF-alpha, interleukin-6, C-reactive protein, adiponectin) markers for adiposity-related co-morbidities and serum alanine aminotransferase (ALT) in 106 school children (65 males, 41 females) 11-15 years of age (mean +/- SD = 13.

Vitamin D, osteocalcin, and risk for adiposity as comorbidities in middle school children.

Nonclassic actions of vitamin D include potential regulation of immune function and glucose homeostasis. The bone-metabolism loop has recently been expanded to include osteocalcin, which appears to play a more direct role in pancreatic beta cell function and energy metabolism. We hypothesized that both vitamin D and osteocalcin would correlate negatively with indices of adiposity-related comorbidity risk in periadolescents, varying by ethnic group.