Advertisement

Topics

PubMed Journal Database | Nano letters RSS

08:25 EST 9th December 2016 | BioPortfolio

The US National Library of Medicine and National Institutes of Health manage PubMed.gov which comprises of more than 21 million records, papers, reports for biomedical literature, including MEDLINE, life science and medical journals, articles, reviews, reports and  books.  BioPortfolio aims to publish relevant information on published papers, clinical trials and news associated with users selected topics.

For example view all recent relevant publications on Epigenetics and associated publications and clincial trials.

Showing PubMed Articles 1–25 of 3,200+ from Nano letters

Quantitative Measurements of Size-Dependent Magnetoelectric Coupling in Fe3O4 Nanoparticles.

Bulk magnetite (Fe3O4), the loadstone used in magnetic compasses, has been known to exhibit magnetoelectric (ME) properties below ∼10 K; however, corresponding ME effects in Fe3O4 nanoparticles have been enigmatic. We investigate quantitatively the ME coupling of spherical Fe3O4 nanoparticles with uniform diameters (d) from 3 to 15 nm embedded in an insulating host, using a sensitive ME susceptometer. The intrinsic ME susceptibility (MES) of the Fe3O4 nanoparticles is measured, exhibiting a maximum value ...

3D DNA Origami cuboids as monodisperse patchy nanoparticles for switchable hierarchical self-assembly.

The rational design of anisotropic interaction patterns is a key step for programming colloid and nanoparticle self-assembly and emergent functions. Herein, we demonstrate a concept for harnessing the capabilities of 3D DNA origami for extensive supracolloidal self-assembly, and showcase its use for making truly monodisperse, patchy, divalent nanocuboids that can self-assemble into supracolloidal fibrils via programmable DNA hybridization. A change in the number of connector duplexes at the patches reveals ...

Passivated Single-crystalline CH3NH3PbI3 Nanowire Photodetector with High Detectivity and Polarization Sensitivity.

Photodetectors convert light signals into current or voltage outputs and are widely used for imaging, sensing and spectroscopy. Recently, perovskite-based photodetectors have shown high sensitivity and fast response due to the unprecedented low recombination loss in this solution processed semiconductor. Among various types of CH3NH3PbI3 morphology (film, single crystal, nanowire), single-crystalline CH3NH3PbI3 nanowires are of particularly interesting for photodetection because of their no grain boundary, ...

Core/Shell Germanium/Germanium-Tin Nanowires Exhibiting Room Temperature Direct- and Indirect-Gap Photoluminescence.

Germanium-tin alloy nanowires hold promise as silicon-compatible optoelectronic elements with the potential for achieving a direct band gap transition required for efficient light emission. In contrast to Ge1-xSnx epitaxial thin films, free-standing nanowires deposited on misfitting germanium or silicon substrates can avoid compressive elastic strains that inhibit formation of a direct gap. We demonstrate strong room temperature photoluminescence, consistent with band edge emission from both the Ge core nan...

Graphene encapsulated copper microwires as highly MRI compatible neural electrodes.

Magnetic resonance imaging (MRI) compatible neural electrodes are important for combining high-resolution electrophysiological measurements with more global MRI mapping of brain activity, which is critical for fundamental neuroscience studies, as well as clinical evaluation and monitoring. Copper is a favorable material to use in MRI because it has magnetic susceptibility close to water and tissues. However, the cytotoxicity of copper precludes its direct implantation for neural recording. Here, we overcome...

Fluid-like Surface Layer and Its Flow Characteristics in Glassy Nanotubes.

Silica glass, with a glass transition temperature in excess of 1000 oC, is not expected to flow at room temperature. In this work, we showed that amorphous silica and Si nanotubes can actually flow at room temperature under Giga-Pascal stress when going to nanometer scale. This creep behavior is unique for the amorphous nanotubes, as it is absent in crystalline Si nanotubes of similar dimensions. The creep is also strongly size-dependent in the amorphous nanotubes with shell thickness down to ~8 nm, which c...

In-situ study of silicon electrode lithiation with X-ray reflectivity.

Surface sensitive X-ray reflectivity (XRR) measurements were performed to investigate the electrochemical lithiation of a native oxide terminated single crystalline silicon (100) electrode in real time during the first galvanostatic discharge cycle. This allows us to gain nanoscale, mechanistic insight into the lithiation of Si and the formation of the solid electrolyte interphase (SEI). We describe an electrochemistry cell specifically designed for in-situ XRR studies and have determined the evolution of t...

Following in real-time the two-step assembly of nanoparticles into mesocrystals in levitating drops.

Mesocrystals composed of crystallographically-aligned nanocrystals are present in biominerals and assembled materials which show strongly directional properties of importance for mechanical protection and functional devices. Mesocrystals are commonly formed by complex biomineralisation processes and can also be generated by assembly of anisotropic nanocrystals. Here, we follow the evaporation-induced assembly of maghemite nanocubes into mesocrystals in real-time in levitating drops. Analysis of time-resolve...

Direct identification and determination of conformational response in adsorbed individual non-planar molecular species using non-contact atomic force microscopy.

In recent years atomic force microscopy (AFM) at highest resolution was widely applied to mostly planar molecules, while its application towards exploring species with structural flexibility and a distinct 3D-character remains a challenge. Herein, the scope of non-contact AFM is widened by investigating subtle conformational differences occurring in the well-studied reference systems 2H-TPP and Cu-TPP on Cu(111). Different saddle-shape conformations of both species can be recognized in conventional constant...

Photon-induced Quantum Oscillations of the Terahertz Conductivity in Graphene.

In this work we present a theory, which is able to explain the non-monotonic decreasing behavior (observed in experimental data(1-11)) of the graphene terahertz conductivity with the increase of the field frequency. In this connection, the displacement of the structure of topological states inside the energy band gap, which appears in graphene due to the strong photon-electron coupling, and the narrowing of this gap, as result of electron transitions from bound photon-dressed electron states to extended sta...

Positive-Negative Birefringence in Multiferroic Layered Metasurfaces.

We uncover and identify the regime for a magnetically and ferroelectrically controllable negative refraction of light traversing multiferroic, oxide-based metastructure consisting of alternating nanoscopic ferroelectric (SrTiO2) and ferromagnetic (Y3Fe2(FeO4)3, YIG) layers. We perform analytical and numerical simulations based on discretized, coupled equations for the self-consistent Maxwell/ferroelectric/ferromagnetic dynamics and obtain a biquadratic relation for the refractive index. Various scenarios of...

Superlattice of Single Atom Magnets on Graphene.

Regular arrays of single atoms with stable magnetization represent the ultimate limit of ultra-high density storage media. Here we report a self-assembled superlattice of individual and non-interacting Dy atoms on graphene grown on Ir(111), with magnetic hysteresis up to 5.6 T and spin lifetime of 1000 s at 2.5 K. The observed magnetic stability is a consequence of the intrinsic low electron and phonon densities of graphene and the six-fold symmetry of the adsorption site. Our single atom magnet array has a...

In situ TEM analysis of organic-inorganic metal-halide perovskite solar cells under electrical bias.

Changes in the nanostructure of methylammonium lead iodide (MAPbI3) perovskite solar cells are assessed as a function of current/voltage stimulus by biasing thin samples in situ in a transmission electron microscope. Various degradation pathways are identified both in situ and ex situ, predominantly at the positively biased MAPbI3 interface. Iodide migrates into the positively biased transport layer and also volatilises along with organic species, which triggers the nucleation of PbI2 nanoparticles and void...

5L-scale Magnesio-milling Reduction of Nanostructured SiO2 for High Capacity Silicon Anodes in Lithium-ion Batteries.

Nanostructured silicon (Si) is useful in many applications, and has typically been synthesized by bottom-up colloid-based solution processes or top-down gas phase reactions at high temperatures. These methods, however, suffer from toxic precursors, low yields, and impractical processing conditions (i.e., high pressure). The magnesiothermic reduction of silicon oxide (SiO2) has also been introduced as an alternative method. Here, we demonstrate the reduction of SiO2 by a simple milling process using a lab-sc...

Intrinsic and Extrinsic Stability of Formamidinium Lead Bromide Perovskite Solar Cells Yielding High Photovoltage.

We report on both intrinsic and extrinsic stability of formamidinium lead bromide [CH(NH2)2PbBr3=FAPbBr3] perovskite solar cell that yield a high photovoltage. The fabrication of FAPbBr3 devices displaying an outstanding photovoltage of 1.53 V and a power conversion efficiency of over 8% was realized by modifying the mesoporous TiO2/FAPbBr3 interface using lithium treatment. Reasons for improved photovoltaic performance were revealed by a combination of techniques, including photothermal deflection absorpti...

The Establishment of 2D Crystal Hetero-structures By Sulfurization of Sequential Transition Metal Depositions: The Preparation, Characterization and Selective Growth.

A 9-layer WS2/MoS2 hetero-structure is established on a sapphire substrate after sequential growth of large-area and uniform 5- and 4- layer MoS2 and WS2 films by using sulfurization of pre-deposited 1.0 nm Molybdenum (Mo) and Tungsten (W), respectively. By using the results obtained from the ultraviolet photoelectron spectroscopy and the absorption spectrum measurements of the standalone MoS2 and WS2 samples, a type-II band alignment is predicated for the WS2/MoS2 hetero-structure. Increasing drain current...

Iridium Oxide - Electrodeposited Nanoporous Gold Multi-Electrode Array with Enhanced Stimulus Efficacy.

A Multi-electrode array (MEA) was fabricated with electrodes consisting of iridium oxide (IrOx) electrochemically deposited on nanoporous gold (NPG) to improve the moderate charge injection limit (ca. 1 mC cm-2) of NPG MEA. IrOx was electrodeposited by performing cyclic voltammetry with an IrOx deposition solution. The IrOx was electrodeposited on Au (EIROF/Au) and on NPG (EIROF/NPG) MEA, and the samples were analyzed in terms of the charge injection limit, charge storage capacity (CSC), and electrochemical...

Subwavelength THz imaging of graphene photoconductivity.

Using a spatially structured, optical pump pulse with a THz probe pulse, we are able to determine spatial variations of the ultrafast THz photoconductivity with sub-wavelength resolution (75 μm ≈ λ/5 at 0.8 THz) in a planar graphene sample. We compare our results to Raman spectroscopy and correlate the existence of the spatial inhomogeneities between the two measurements. We find a strong correlation with inhomogeneity in electron density. This demonstrates the importance of eliminating inhomogeneities ...

In Situ Reactive Synthesis of Polypyrrole-MnO2 Coaxial Nanotubes as Sulfur Hosts for High-Performance Lithium-Sulfur Battery.

Lithium-sulfur batteries are considered as a promising candidate for high energy density storage applications. However, their specific capacity and cyclic stability are hindered by poor conductivity of sulfur and the dissolution of redox intermediates. Here we design polypyrrole-MnO2 coaxial nanotubes to encapsulate sulfur, in which MnO2 restrains the shuttle effect of polysulfides greatly through chemisorption and polypyrrole serves as conductive frameworks. The polypyrrole-MnO2 nanotubes are synthesized t...

High-Density Nanosharp Microstructures Enable Efficient CO2 Electroreduction.

Conversion of CO2 to CO powered by renewable electricity not only reduces CO2 pollution, but also is a means to store renewable energy via chemical production of fuels from CO. However, the kinetics of this reaction are slow due its large energetic barrier. We have recently reported CO2 reduction that is considerably enhanced via local electric field concentration at the tips of sharp gold nanostructures. The high local electric field enhances CO2 concentration at the catalytic active sites, lowering the ac...

A New Line Defect in NdTiO3 Perovskite.

Perovskite oxides form an eclectic class of materials owing to their structural flexibility in accommodating cations of different sizes and valences. They host well known point and planar defects, but so far no line defect has been identified other than dislocations. Using analytical scanning transmission electron microscopy (STEM) and ab initio calculations we have detected and characterized the atomic and electronic structures of a novel line defect in NdTiO3 perovskite. It appears in STEM images as a per...

Unusual Multiferroic Phase Transitions in PbTiO3 Nanowires.

Unconventional phases and their transitions in nanoscale systems are recognized as an intriguing avenue for both unique physical properties and novel technological paradigms. Although the multiferroic phase has attracted considerable attention due to the coexistence and cross-coupling of electric and magnetic order parameters, mutually exclusive mechanism between ferroelectricity and ferromagnetism leaves conventional ferroelectrics such as PbTiO3 simply nonmagnetic. Here, we demonstrate from first principl...

Normal-Incidence PEEM Imaging of Propagating Modes in a Plasmonic Nanocircuit.

The design of noble-metal plasmonic devices and nanocircuitry requires a fundamental understanding and control of the interference of plasmonic modes. Here we report the first visualization of the propagation and interference of guided modes in a showcase plasmonic nanocircuit using normal-incidence nonlinear two-photon photoemission electron microscopy (PEEM). We demonstrate that in contrast to the commonly used grazing-incidence illumination scheme, normal-incidence PEEM provides a direct image of the str...

Al-Pd Nanodisk Heterodimers as Antenna-Reactor Photocatalysts.

Photocatalysis uses light energy to drive chemical reactions. Conventional industrial catalysts are made of transition metal nanoparticles that interact only weakly with light, while metals such as Au, Ag, and Al that support surface plasmons interact strongly with light but are poor catalysts. By combining plasmonic and catalytic metal nanoparticles, the plasmonic "antenna" can couple light into the catalytic "reactor". This interaction induces an optical polarization in the reactor nanoparticle, forcing a...

Ternary FexCo1-xP Nanowire Array as a Robust Hydrogen Evolution Reaction Electrocatalyst with Pt-like Activity: Experimental and Theoretical Insight.

Replacement of precious Pt with earth-abundant electrocatalysts for the hydrogen evolution reaction (HER) holds great promise for clean energy devices, but the development of low-cost and durable HER catalysts with Pt-like activity is still a huge challenge. In this communication, we report on the development of self-standing ternary FexCo1-xP nanowire array on carbon cloth (FexCo1-xP/CC) as a Pt-free HER catalyst with activities being strongly related to Fe substitution ratio. Electrochemical tests show th...


Quick Search
Advertisement