No abstract

For the first time, we report a complete control of crystal structure in InAs(1-x)Sb(x) NWs by tuning the antimony (Sb) composition. This claim is substantiated by high-resolution transmission electron microscopy combined with photoluminescence spectroscopy. The pure InAs nanowires generally show a mixture of wurtzite (WZ) and zinc-blende (ZB) phases, where addition of a small amount of Sb (∼2-4%) led to quasi-pure WZ InAsSb NWs, while further increase of Sb (∼10%) resulted in quasi-pure ZB InAsSb NWs. This phase transition is further evidenced by photoluminescence (PL) studies, where a dominant emission associated with the coexistence of WZ and ZB phases is present in the pure InAs NWs but absent in the PL spectrum of InAs0.96Sb0.04 NWs that instead shows a band-to-band emission. We also demonstrate that the Sb addition significantly reduces the stacking fault density in the NWs. This study provides new insights on the role of Sb addition for effective control of nanowire crystal structure.

No abstract

Alzheimer’s disease (AD) is influenced by both genetic and environmental factors; thus, brain epigenomic alterations may provide insights into AD pathogenesis. Multiple array-based Epigenome-Wide Association Studies (EWASs) have identified robust brain methylation changes in AD; however, array-based assays only test about 2% of all CpG sites in the genome. Here, we develop EWASplus, a computational method that uses a supervised machine learning strategy to extend EWAS coverage to the entire genome. Application to six AD-related traits predicts hundreds of new significant brain CpGs associated with AD, some of which are further validated experimentally. EWASplus also performs well on data collected from independent cohorts and different brain regions. Genes found near top EWASplus loci are enriched for kinases and for genes with evidence for physical interactions with known AD genes. In this work, we show that EWASplus implicates additional epigenetic loci for AD that are not found using array-based AD EWASs.

This paper presents a novel autonomous shipboard landing control algorithm of a quadrotor subject to external disturbances and input saturation. A coupled six-degrees-of-freedom (6-DOF) nonlinear relative motion model is derived to facilitate the controller design. To overcome the under-actuated property of the quadrotor and avoid collision, the shipboard landing process is cooperatively completed by a relative position controller (RPC) and a relative attitude-altitude controller (RAC). The RPC is proposed for use when the quadrotor is far away from the ship, aiming to drive the quadrotor to the vicinity of the ship. The RAC is used for the situation when the quadrotor is close enough to the ship to land the quadrotor on the ship steadily. An adaptive backstepping technique is proposed for both RPC and RAC, where unknown bounds of the lump disturbances are estimated online by the adaptive laws. To satisfy the input constraint requirement, a smooth model is employed to describe the control input saturation. Stability analysis proves that all states of the closed-loop systems are uniformly ultimately bounded. A numerical example verifies the performance of the control approach.

No abstract

No abstract

No abstract