High-Dose Neonatal Vitamin A Supplementation Transiently Decreases Thymic Function in Early Infancy.

BACKGROUND: Vitamin A deficiency (VAD) impairs T-cell-mediated immunity. In regions where VAD is prevalent, vitamin A supplementation (VAS) reduces child mortality, perhaps by improving immune function. OBJECTIVE: Our objective was to determine if neonatal VAS would improve thymic function in Bangladeshi infants, and to determine if such effects differed by sex or nutritional status (i.e., birth weight above/below the median). METHODS: Three hundred and six infants were randomly assigned to 50,000 IU vitamin A (VA) or placebo (PL) within 48 h of birth. Primary outcomes were measured at multiple ages and included 1) thymic index (TI) at 1, 6, 10, and 15 wk; 2) T-cell receptor excision circles (TREC), an index of thymic output of naïve T cells; and 3) total/naïve T cells in peripheral blood at 6 wk, 15 wk, and 2 y. A mixed linear model for repeated measures was used to assess group differences at each age and identify interactions with sex and birth weight. RESULTS: VAS did not significantly (P = 0.21) affect TI overall (i.e., at all ages) but decreased TI by 7.8% (P = 0.029) at 6 wk: adjusted TI means for the PL and VA groups at 1, 6, 10, and 15 wk were 4.09 compared with 3.80 cm2, 7.78 compared with 7.18 cm2, 8.11 compared with 7.84 cm2, and 7.91 compared with 7.97 cm2, respectively. VAS did not significantly (P = 0.25) affect TREC overall but decreased TREC by 19% (P = 0.029) at 15 wk: adjusted TREC means for the PL and VA groups at 6 wk, 15 wk, and 2 y were 13.6 compared with 16.1 copies/pg DNA, 19.4 compared with 15.7 copies/pg DNA, and 11.8 compared with 10.0 copies/pg DNA, respectively. VAS did not significantly affect overall total (P = 0.10) or naïve (P = 0.092) T cells: adjusted naïve T-cell means for the PL and VA groups at 6 wk, 15 wk, and 2 y were 3259 compared with 3109 cells/µL, 3771 compared with 3487 cells/µL, and 1976 compared with 1898 cells/µL, respectively. CONCLUSION: In contrast to our hypothesis, VAS decreased thymic function early in infancy but health effects are presumably negligible owing to the transience and small magnitude of this effect. This trial was registered at clinicaltrials.gov as NCT01583972 and NCT02027610.

Self-Assembled N/S Codoped Flexible Graphene Paper for High Performance Energy Storage and Oxygen Reduction Reaction.

A novel flexible three-dimensional (3D) architecture of nitrogen and sulfur codoped graphene has been successfully synthesized via thermal treatment of a liquid crystalline graphene oxide-doping agent composition, followed by a soft self-assembly approach. The high temperature process turns the layer-by-layer assembly into a high surface area macro- and nanoporous free-standing material with different atomic configurations of graphene. The interconnected 3D network exhibits excellent charge capacitive performance of 305 F g(-1) (at 100 mV s(-1)), an unprecedented volumetric capacitance of 188 F cm(-3) (at 1 A g(-1)), and outstanding energy density of 28.44 Wh kg(-1) as well as cycle life of 10 000 cycles as a free-standing electrode for an aqueous electrolyte, symmetric supercapacitor device. Moreover, the resulting nitrogen/sulfur doped graphene architecture shows good electrocatalytic performance, long durability, and high selectivity when they are used as metal-free catalyst for the oxygen reduction reaction. This study demonstrates an efficient approach for the development of multifunctional as well as flexible 3D architectures for a series of heteroatom-doped graphene frameworks for modern energy storage as well as energy source applications.