ABSTRACT
This paper describes the self-assembly of oligosaccharide-based hybrid block copolymers (BCPs) consisting of maltoheptaose (MH) and poly(methyl methacrylate) (PMMA) into 10nm scale lamellar and cylindrical phases depending on the volume fractions of MH (ÏMH) and the annealing process. Time resolved SAXS study of the BCP bulk samples during thermal annealing indicated that the BCPs phase separate into 10nm scale periodical structures. The solvent vapor annealing induced self-organizations of the BCP into different phases depending on ÏMH and the weight fraction of THF/H2O. BCPs with relatively higher ØMH, MH-b-PMMA3k (ÏMH=0.27) and MH-b-PMMA5k (ÏMH=0.16) self-organized into lamellar phases while the BCP sample with relatively lower ÏMH, MH-b-PMMA9k (ÏMH=0.10), self-organized into cylindrical phase by using THF/H2O=1/4 (w/w). On the other hand, the solvent vapor annealing with larger fraction of THF, i.e. THF/H2O=2/3 (w/w), induced cylindrical phases for MH-b-PMMA3k and MH-b-PMMA5k.
ABSTRACT
BACKGROUND: Overweight and obesity in childhood are a major concern in developed countries. Reference growth curves are used in current practice to identify children at risk, especially at risk of overweight or obesity. National reference growth curves were published 35 years ago from children born in the 1950s to study growth from birth to adulthood. Additionally, more recent national curves exist to study birth weight and height according to gestational age. The primary objective was to describe anthropometric measurements of French children born in the 2000s and to compare them with the French references. The secondary objective was to describe overweight indicators during infancy. METHODS: A total of 77,315 singletons live-born from 1 July 2004 to 31 December 2013 recorded in the Efemeris (a French cohort of women and their children) were included. The z-score means based on the French references for weight, height, and body mass index (BMI) at birth, 9 months, and 24 months were calculated. RESULTS: At birth, the weight and height of the cohort did not deviate from the recent French references taking into account gestational age. At 9 and 24 months, the cohort was between 0.12 and 0.39 standard deviations (SD) heavier and between 0.70 and 0.97 SD taller than the old French reference population. Between 0 and 2 years, 28.6% of the children underwent a rapid weight gain (change in SD scores>0.67). The prevalence of overweight at 2 years was between 5 and 6% using the International obesity task force (IOTF) references. CONCLUSION: The distributions of the height, weight, and BMI during early childhood differ from those of children in the national growth references. Contemporary children at 2 years are taller and heavier than children born in the 1950s. Approximately one in 20 children is overweight at 2 years.