Zika virus (ZIKV) has evolved into a global health threat because of its unexpected causal link to microcephaly. Phylogenetic analysis reveals that contemporary epidemic strains have accumulated multiple substitutions from their Asian ancestor. Here we show that a single serine-to-asparagine substitution [Ser139→Asn139 (S139N)] in the viral polyprotein substantially increased ZIKV infectivity in both human and mouse neural progenitor cells (NPCs) and led to more severe microcephaly in the mouse fetus, as well as higher mortality rates in neonatal mice. Evolutionary analysis indicates that the S139N substitution arose before the 2013 outbreak in French Polynesia and has been stably maintained during subsequent spread to the Americas. This functional adaption makes ZIKV more virulent to human NPCs, thus contributing to the increased incidence of microcephaly in recent ZIKV epidemics.
BiFeO 3 was studied as an alternative environmentally clean ferro/piezoelectric material. 200-nm-thick BiFeO 3 films were grown on Si substrates with SrTiO 3 as a template layer and SrRuO 3 as bottom electrode. X-ray and transmission electron microscopy studies confirmed the epitaxial growth of the films. The spontaneous polarization of the films was ϳ45 C/cm 2 . Retention measurement up to several days showed no decay of polarization. A piezoelectric coefficient ͑d 33 ͒ of ϳ60 pm/ V was observed, which is promising for applications in micro-electro-mechanical systems and actuators.
An all-perovskite ferroelectric field-effect transistor with a ferroelectric Pb(Zr 0.2 Ti 0.8)O 3 ͑PZT͒ gate and a colossal magnetoresistive La 0.8 Ca 0.2 MnO 3 ͑LCMO͒ channel has been successfully fabricated by pulsed-laser deposition on Si. A clear and square channel resistivity hysteresis loop, commensurate with the ferroelectric hysteresis loop of PZT, is observed. A maximum modulation of 20% after an electric field poling of 1.5ϫ10 5 V/cm, and 50% under a magnetic field of 1 T, are achieved near the metal-insulator transition temperature of the LCMO channel. A data retention time of at least one day is measured. The effects of electric and magnetic fields on the LCMO channel resistance are discussed within the framework of phase separation scenario.
New oxyfluoride glass with high fluorine content and laser patterning of nonlinear optical BaAlBO3F2 single crystal line J. Appl. Phys. 112, 093506 (2012) Doping level dependent space charge limited conduction in polyaniline nanoparticles J. Appl. Phys. 112, 093704 (2012) Controllable aggregates of silver nanoparticle induced by methanol for surface-enhanced Raman scattering Appl. Phys. Lett. 101, 173109 (2012) CdSe quantum dots-poly(3-hexylthiophene) nanocomposite sensors for selective chloroform vapor detection at room temperature Appl. Phys. Lett. 101, 173108 (2012) An "edge to edge" jigsaw-puzzle two-dimensional vapor-phase transport growth of high-quality large-area wurtzite-type ZnO (0001) nanohexagons Appl.
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