Effects of lead on the somatic growth of children

Studies on the effects of lead on the somatic growth of children are limited and contradictory. The authors investigated the adverse effects of blood lead concentration on the somatic growth of primary-school-age children. In this study, there was a total of 522 children, aged 6–9 y, who resided in three areas of Greece (i.e., Loutraki, Lavrion, and Elefsina). The medical evaluation included medical history; physical examination; and measurements of height, head circumference, and chest circumference. The authors also evaluated dietary information, socioeconomic status, and height of parents. The authors conducted laboratory tests for hematological parameters and blood lead levels. The mean blood lead level was 12.3 μg/dl (standard deviation = 8.9 μg/dl), and levels ranged from 1.3 μg/dl to 51.2 μg/dl. There were negative monotonic relationships between growth parameters and blood lead levels, even after the authors allowed for confounding effects. An increase in blood lead level of 10 μg/dl was associated with a decrease of (a) 0.33 cm in head circumference (95% confidence interval = 0.12, 0.55; p =.002); (b) 0.86 cm in height (95% confidence interval = 0.14, 1.16; p =.020); and (c) 0.40 cm in chest circumference (95% confidence interval = −0.22, 1.02; p =.207). These findings led the authors to conclude that a decrease in growth in children may be associated with blood lead concentrations. © 1997 Taylor & Francis Group, LLC

Near-IR absorbing molecular semiconductors incorporating cyanated benzothiadiazole acceptors for high performance semi-transparent n-type organic field-effect transistors

Small band gap molecular semiconductors are of interest for the development of transparent electronics. Here we report two near-infrared (NIR), n-type small molecule semiconductors, based upon an acceptor-donor-acceptor (A-D-A) approach. We show that the inclusion of molecular spacers between the strong electron accepting end group, 2,1,3-benzothiadiazole-4,5,6-tricarbonitrile, and the donor core affords semiconductors with very low band gaps down to 1 eV. Both materials were synthesised by a one-pot, sixfold nucleophilic displacement of a fluorinated precursor by cyanide. Significant differences in solid-state ordering and charge carrier mobility are observed depending on the nature of the spacer, with a thiophene spacer resulting in solution processed organic field-effect transistors (OFETs) exhibiting excellent electron mobility up to 1.1 cm2 V-1s-1. The use of silver nanowires as the gate electrodes enables the fabrication of semi-transparent OFET device with average visible transmission of 71% in the optical spectrum