The homozygous p.V37I variant of GJB2 is frequent in East Asians and has been reported to have a pathogenic role in mild-to-moderate hearing impairment (HI). In this study, we investigated the prevalence and phenotypic spectrum of homozygous p.V37I in three Chinese Han cohorts with severe-to-profound HI (n = 857, Cohort S), mild-to-moderate HI (n = 88, Cohort M) and normal hearing (n = 1550, Cohort N). Sequencing of GJB2 showed that homozygous p.V37I was detected in 1.63% (14/857), 12.5% (11/88) and 0.32% (5/1550) of subjects in Cohorts S, M and N, respectively. It was strongly associated with both mild-to-moderate (p = 2.0 × 10(-11) ) and severe-to-profound (p = 0.001) HI, but was estimated to have a rather low penetrance (17%). Among the hearing impaired subjects with homozygous p.V37I, the onset of HI was congenital in 65% (11/17) and delayed in 35% (6/17). By targeted next-generation sequencing of 79 known deafness genes, we identified an additional homozygous pathogenic mutation of CDH23 in 1 of 14 p.V37I homozygous subjects from Cohort S. Our study suggested that homozygous p.V37I is associated with a broader spectrum of hearing phenotypes than previously revealed. Data presented in this study can be effectively applied to clinical evaluation and genetic counseling of people carrying this variant.

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In this work, continuous conversion coatings on the surface of in situ TiB 2 particulate reinforced A356 composite were formed successfully by cerium surface treatment for the first time. Scanning electron microscope (SEM) analysis showed that the conversion coatings were inhomogeneous and could be divided into two types of regions, namely, fine crack region and noncrack region. Many cerium-rich nano-nodules were uniformly distributed in the whole coatings. Energy dispersive spectroscopy (EDS) analysis testified that the crack coatings mainly covered the interdendritic sites occupied by TiB 2 particulates and Si phases. X-ray photoelectron spectroscopy (XPS) analysis indicated that the conversion coatings were composed of CeO 2 , Ce 2 O 3 , Ce(OH) 4 , Ce(OH) 3 , and a little amount of Al 2 O 3 . The electrochemical polarization tests showed that the cerium-conversion treatment markedly improved the corrosion resistance of in situ TiB 2p /A356 composite in chloride environment, and the protection degree of the coatings was superior to that of conventional chromate-conversion coating. According to these results, the formation mechanism of cerium-conversion coatings was discussed.

In many flying insects, forewings and hindwings are coupled mechanically to achieve flapping flight synchronously while being driven by action of the forewings. How the forewings and hindwings as well as their morphologies contribute to aerodynamic force production and flight control remains unclear. Here we address the point that the forewings can produce most of the aerodynamic forces even with the hindwings removed through a computational fluid dynamic study of three revolving insect wing models, which are identical to the wing morphologies and Reynolds numbers of hawkmoth (Manduca sexta), bumblebee (Bombus ignitus) and fruitfly (Drosophila melanogaster). We find that the forewing morphologies match the formation of leading-edge vortices (LEV) and are responsible for generating sufficient lift forces at the mean angles of attack and the Reynolds numbers where the three representative insects fly. The LEV formation and pressure loading keep almost unchanged with the hindwing removed, and even lead to some improvement in power factor and aerodynamic efficiency. Moreover, our results indicate that the size and strength of the LEVs can be well quantified with introduction of a conical LEV angle, which varies remarkably with angles of attack and Reynolds numbers but within the forewing region while showing less sensitivity to the wing morphologies. This implies that the forewing morphology very likely plays a dominant role in achieving low-Reynolds number aerodynamic performance in natural flyers as well as in revolving and/or flapping micro air vehicles.