Associations of autozygosity with a broad range of human phenotypes

In many species, the offspring of related parents suffer reduced reproductive success, a phenomenon known as inbreeding depression. In humans, the importance of this effect has remained unclear, partly because reproduction between close relatives is both rare and frequently associated with confounding social factors. Here, using genomic inbreeding coefficients (FROH) for >1.4 million individuals, we show that FROH is significantly associated (p < 0.0005) with apparently deleterious changes in 32 out of 100 traits analysed. These changes are associated with runs of homozygosity (ROH), but not with common variant homozygosity, suggesting that genetic variants associated with inbreeding depression are predominantly rare. The effect on fertility is striking: FROH equivalent to the offspring of first cousins is associated with a 55% decrease [95% CI 44–66%] in the odds of having children. Finally, the effects of FROH are confirmed within full-sibling pairs, where the variation in FROH is independent of all environmental confounding

Strong anisotropy of ferroelectricity in lead-free bismuth silicate

Bismuth silicate (Bi2SiO5) was recently suggested as a potential silicate based lead-free ferroelectric material. Here, we show the existence of ferroelectricity and explore the strong anisotropy of local ferroelectricity using piezoresponse force microscopy (PFM). Domain structures are reconstructed using angle-resolved PFM. Furthermore, piezoresponse hysteresis loops and piezoelectric coefficients are spatially investigated at the nanoscale. The obtained results confirm the existence of ferroelectricity with strong c-axis polarization. These results could provide basic information on the anisotropic ferroelectricity in Bi2SiO5 and furthermore suggest its considerable potential for lead-free ferroelectric applications with silicon technologies111101sciescopu

Enhanced thermoelectric performance of Bi0.5Sb1.5Te3-expanded graphene composites by simultaneous modulation of electronic and thermal carrier transport

Solution-based synthesis of thermoelectric nanoplates, which provides a low thermal conductivity due to the grain boundary scattering, has received considerable attention as a scalable method. However, the scattering also decreased electrical conductivity leading to a low thermoelectric figure of merit (ZT). Here we employed expanded graphene to enhance thermoelectric performance of p-type Bi0.5Sb1.5Te3 composites by simultaneous improvement in electrical conduction and phonon scattering. The addition of expanded graphene (0.1vol%) improved both carrier concentration and electrical conductivity of composites due to the high intrinsic p-type carrier concentration of graphene. Besides, it significantly decreased lattice thermal conductivity due to the phase boundary phonon scattering in spite of the high intrinsic thermal conductivity of graphene. The increased carrier concentration also suppressed the bipolar conduction resulting in a moderate increase in power factor and a slow increase in bipolar thermal conductivity at elevated temperatures. Overall, the maximum ZT increased by 45% (1.13 at 360K) by the addition of expanded graphene. A similar trend with a greater maximum ZT (1.24 at 360K) was observed when ball-milled Bi0.5Sb1.5Te3 ingot powders were employed providing reliability of the suggested mechanism. © 2015 Elsevier Ltd126251sciescopu

Direct Observation of Inherent Atomic-Scale Defect Disorders responsible for High-Performance Ti1-xHfxNiSn1-ySby Half-Heusler Thermoelectric Alloys

Structural defects often dominate the electronic- and thermal-transport properties of thermoelectric (TE) materials and are thus a central ingredient for improving their performance. However, understanding the relationship between TE performance and the disordered atomic defects that are generally inherent in nanostructured alloys remains a challenge. Herein, the use of scanning transmission electron microscopy to visualize atomic defects directly is described and disordered atomic-scale defects are demonstrated to be responsible for the enhancement of TE performance in nanostructured Ti1-xHfxNiSn1-ySby half-Heusler alloys. The disordered defects at all atomic sites induce a local composition fluctuation, effectively scattering phonons and improving the power factor. It is observed that the Ni interstitial and Ti,Hf/Sn antisite defects are collectively formed, leading to significant atomic disorder that causes the additional reduction of lattice thermal conductivity. The Ti1-xHfxNiSn1-ySby alloys containing inherent atomic-scale defect disorders are produced in one hour by a newly developed process of temperature-regulated rapid solidification followed by sintering. The collective atomic-scale defect disorder improves the zT to 1.09 +/- 0.12 at 800 K for the Ti0.5Hf0.5NiSn0.98Sb0.02 alloy. These results provide a promising avenue for improving the TE performance of state-of-the-art materials. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinhei