Influence of uniaxial tensile stress on the mechanical and piezoelectric properties of short-period ferroelectric superlattice

Tetragonal ferroelectric/ferroelectric BaTiO3/PbTiO3 superlattice under uniaxial tensile stress along the c axis is investigated from first principles. We show that the calculated ideal tensile strength is 6.85 GPa and that the superlattice under the loading of uniaxial tensile stress becomes soft along the nonpolar axes. We also find that the appropriately applied uniaxial tensile stress can significantly enhance the piezoelectricity for the superlattice, with piezoelectric coefficient d33 increasing from the ground state value by a factor of about 8, reaching 678.42 pC/N. The underlying mechanism for the enhancement of piezoelectricity is discussed

MicroRNA-1 Regulates Smooth Muscle Cell Differentiation by Repressing Kruppel-Like Factor 4

The role of microRNA-1 (miR-1) has been studied in cardiac and skeletal muscle differentiation. However, it remains unexplored in vascular smooth muscle cells (SMCs) differentiation. The aim of this study was to uncover novel targets of and shed light on the function of miR-1 in the context of embryonic stem cell (ESC) differentiation of SMCs in vitro. miR-1 expression is steadily increased during differentiation of mouse ESC to SMCs. Loss-of-function approaches using miR-1 inhibitors uncovered that miR-1 is required for SMC lineage differentiation in ESC-derived SMC cultures, as evidenced by downregulation of SMC-specific markers and decrease of derived SMC population. In addition, bioinformatics analysis unveiled a miR-1 binding site on the Kruppel-like factor 4 (KLF4) 3' untranslated region (3-UTR), in a region that is highly conserved across species. Consistently, miR-1 mimic reduced KLF4 3-UTR luciferase activity, which can be rescued by mutating the miR-1 binding site on the KLF4 3-UTR in the reporter construct. Additionally, repression of the miR-1 expression by miR-1 inhibitor can reverse KLF4 downregulation during ESC-SMC differentiation, which subsequently inhibits SMC differentiation. We conclude that miR-1 plays a critical role in the determination of SMC fate during retinoid acid-induced ESC/SMC differentiation, which may indicate that miR-1 has a role to promote SMC differentiation.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/90488/1/scd-2E2010-2E0283.pd

Effects of acceleration on the collision of particles in the rotating black hole spacetime

We study the collision of two geodesic particles in the accelerating and rotating black hole spacetime and probe the effects of the acceleration of black hole on the center-of-mass energy of the colliding particles and on the high-velocity collision belts. We find that the dependence of the center-of-mass energy on the acceleration in the near event-horizon collision is different from that in the near acceleration-horizon case. Moreover, the presence of the acceleration changes the shape and position of the high-velocity collision belts. Our results show that the acceleration of black holes brings richer physics for the collision of particles.Comment: 7 pages, 2 figures, The corrected version accepted for publication in EPJ

Novel Online Sequential Learning-Based Adaptive Routing for Edge Software-Defined Vehicular Networks

To provide efficient networking services at the edge of Internet-of-Vehicles (IoV), Software-Defined Vehicular Network (SDVN) has been a promising technology to enable intelligent data exchange without giving additional duties to the resource constrained vehicles. Compared with conventional centralized SDVNs, hybrid SDVNs combine the centralized control of SDVNs and self-organized distributed routing of Vehicular Ad-hoc NETworks (VANETs) to mitigate the burden on the central controller caused by the frequent uplink and downlink transmissions. Although a wide variety of routing protocols have been developed, existing protocols are designed for specific scenarios without considering flexibility and adaptivity in dynamic vehicular networks. To address this problem, we propose an efficient online sequential learning-based adaptive routing scheme, namely, Penicillium reproduction-based Online Learning Adaptive Routing scheme (POLAR) for hybrid SDVNs. By utilizing the computational power of edge servers, this scheme can dynamically select a routing strategy for a specific traffic scenario by learning the pattern from network traffic. Firstly, this paper applies Geohash to divide the large geographical area into multiple grids, which facilitates the collection and processing of real-time traffic data for regional management in controller

Mechanical characterization of individual Ni∕Au coated microsize polymer particles

This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Institute of Physics. The following article appeared in (DOU, G., WHALLEY, D.C. and LIU, C., 2008. Mechanical characterization of individual Ni/Au coated microsize polymer particles. Applied Physics Letters, 92(10), 104108 (8 Pages)) and may be found at http://link.aip.org/link/?APPLAB/92/104108/1We report on a mechanical characterization technique for individual Ni/Au coated microsize polymer particles. This technique allows a clearer understanding of the effects of load force and rate on the particle deformation. This has been achieved through measurements of the deformation against force using a specially configured nanoindenter machine, where the “indenters,” instead of being pointed, had a flat tip of 20 m in diameter. The results show that the particle deformation process is nonlinear and that the force/deformation at which particle crushing occurs is affected by the load rate. The technique could be used to design/manufacture more effective conductive particles

Chemiluminescence determination of surfactant Triton X-100 in environmental water with luminol-hydrogen peroxide system

<p>Abstract</p> <p>Background</p> <p>The rapid, simple determination of surfactants in environmental samples is essential because of the extensive use and its potential as contaminants. We describe a simple, rapid chemiluminescence method for the direct determination of the non-ionic surfactant Triton X-100 (polyethylene glycol tert-octylphenyl ether) in environmental water samples. The optimized experimental conditions were selected, and the mechanism of the Luminol-H₂O₂-Triton X-100 chemiluminesence system was also studied.</p> <p>Results</p> <p>The novel chemiluminescence method for the determination of non-ionic surfactant Triton X-100 was based on the phenomenon that Triton X-100 greatly enhanced the CL signal of the luminol-H₂O₂system. The alkaline medium of luminol and the pH value obviously affected the results. Luminol concentration and hydrogen peroxide concentration also affected the results. The optimal conditions were: Na₂CO₃being the medium, pH value 12.5, luminol concentration 1.0 × 10^-4mol L^-1, H₂O₂concentration 0.4 mol L^-1. The possible mechanism was studied and proposed.</p> <p>Conclusion</p> <p>Under the optimal conditions, the standard curve was drawn up and quotas were evaluated. The linear range was 2 × 10^-4g·mL^-1-4 × 10^-2g·mL^-1(w/v), and the detection limit was 3.97 × 10^-5g·mL^-1Triton X-100 (w/v). The relative standard deviation was less than 4.73% for 2 × 10^-2g·mL^-1(w/v) Triton X-100 (n = 7). This method has been applied to the determination of Triton X-100 in environmental water samples. The desirable recovery ratio was between 96%–102% and the relative standard deviation was 2.5%–3.3%. The luminescence mechanism was also discussed in detail based on the fluorescence spectrum and the kinetic curve, and demonstrated that Triton X-100-luminol-H₂O₂was a rapid reaction.</p

liver-enriched gene 1a and 1b Encode Novel Secretory Proteins Essential for Normal Liver Development in Zebrafish

liver-enriched gene 1 (leg1) is a liver-enriched gene in zebrafish and encodes a novel protein. Our preliminary data suggested that Leg1 is probably involved in early liver development. However, no detailed characterization of Leg1 has been reported thus far. We undertook both bioinformatic and experimental approaches to study leg1 gene structure and its role in early liver development. We found that Leg1 identifies a new conserved protein superfamily featured by the presence of domain of unknown function 781 (DUF781). There are two copies of leg1 in zebrafish, namely leg1a and leg1b. Both leg1a and leg1b are expressed in the larvae and adult liver with leg1a being the predominant form. Knockdown of Leg1a or Leg1b by their respective morpholinos specifically targeting their 5′-UTR each resulted in a small liver phenotype, demonstrating that both Leg1a and Leg1b are important for early liver development. Meanwhile, we found that injection of leg1-ATGMO, a morpholino which can simultaneously block the translation of Leg1a and Leg1b, caused not only a small liver phenotype but hypoplastic exocrine pancreas and intestinal tube as well. Further examination of leg1-ATGMO morphants with early endoderm markers and early hepatic markers revealed that although depletion of total Leg1 does not alter the hepatic and pancreatic fate of the endoderm cells, it leads to cell cycle arrest that results in growth retardation of liver, exocrine pancreas and intestine. Finally, we proved that Leg1 is a secretory protein. This intrigued us to propose that Leg1 might act as a novel secreted regulator that is essential for liver and other digestive organ development in zebrafish