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PubMed Journal Database | Nano letters RSS

18:23 EDT 28th May 2017 | 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 3,400+ from Nano letters

Inter-granular cracking as a major cause of long-term capacity fading of layered cathodes.

Capacity fading has limited commercial layered Li-ion battery electrodes to

Structural Distortions and Charge Density Waves in Iodine Chains Encapsulated inside Carbon Nanotubes.

Atomic chains are perfect systems for getting fundamental insights into the electron dynamics and coupling between the electronic and ionic degrees of freedom in one dimensional metals. Depending on the band filling, they can exhibit Peierls instabilities (or charge density waves), where equally spaced chain of atoms with partially filled band is inherently unstable, exhibiting spontaneous distortion of the lattice that further leads to metal-insulator transition in the system. Here, using high-resolution s...

Experimental demonstration of complete 180(o) reversal of magnetization in isolated Co nanomagnets on a PMN-PT substrate with voltage generated strain.

Rotating the magnetization of a shape anisotropic magnetostrictive nanomagnet with voltage-generated stress/strain dissipates much less energy than most other magnetization rotation schemes, but its application to writing bits in non-volatile magnetic memory has been hindered by the fundamental inability of stress/strain to rotate magnetization by full 180(o). Normally, stress/strain can rotate the magnetization of a shape anisotropic elliptical nanomagnet by only up to 90(o), resulting in incomplete magnet...

Direct imaging of kinetic pathways of atomic diffusion in monolayer molybdenum disulfide.

Direct observation of atomic migration both on and below surfaces is a long-standing but important challenge in materials science as diffusion is one of the most elementary processes essential to many vital material behaviors. Probing the kinetic pathways, including metastable or even transition states involved down to atomic scale, holds the key to the underlying physical mechanisms. Here, we applied aberration-corrected transmission electron microscopy (TEM) to demon-strate direct atomic-scale imaging and...

Emergent optical phononic modes upon nanoscale mesogenic phase transitions.

The investigation of phononic collective excitations in soft matter systems at the molecular scale has always been challenging due to limitations of experimental techniques in resolving low-energy modes. Recent advances in Inelastic X-ray Scattering (IXS) enabled the study of such systems with unprecedented spectral contrast at meV excitation energies. In particular, it has become possible to shed light on the low-energy collective motions in materials whose morphology and phase behavior can easily be manip...

Young's Modulus of Wurtzite and Zinc Blende InP Nanowires.

The Young's modulus of thin conical InP nanowires with either wurtzite or mixed "zinc blende/wurtzite" structures was measured. It has been shown that the value of Young's modulus obtained for wurtzite InP nanowires (E[0001]=130 ± 30 GPa) was similar to the theoretically predicted value for the wurtzite InP material (E[0001]=120 ± 10 GPa). The Young's modulus of mixed "zinc blende/wurtzite" InP nanowires (E[111]=65 ± 10 GPa) appeared to be 40% less then theoretically predicted value for the zinc blende I...

Correction to Sequence of Silicon Monolayer Structures Grown on a Ru Surface: from a Herringbone Structure to Silicene.

Ultrafast carbon dioxide sorption kinetics using lithium silicate nanowires.

In this paper, the Li4SiO4 nanowires (NW) were shown to be promising for CO2 capture with ultrafast kinetics. Specifically, the nanowire powders exhibited an uptake of 0.35 g g-1 of CO2 at ultra-fast adsorption rate of 0.22 g g-1 min-1 at 650-700°C. Lithium silicate (Li4SiO4) nanowires and nanopowders were synthesized using a "solvo-plasma" technique involving plasma oxidation of silicon precursors mixed with lithium hydroxide. The kinetic parameter values (k) extracted from sorption and desorption kinetic...

Room-temperature InP/InAsP Quantum Discs-in-nanowire Infrared Photodetectors.

The possibility to engineer nanowire heterostructures with large bandgap variations is particularly interesting for technologically important broadband photodetector applications. Here we report on a combined study of design, fabrication and optoelectronic properties of infrared photodetectors comprising 4 million n+-i-n+ InP nanowires periodically ordered in arrays. The nanowires were grown by metal-organic vapor phase epitaxy on InP substrates, with either a single or 20 InAsP quantum discs embedded in th...

Ten-fold Enhancement of InAs Nanowire Photoluminescence Emission with an InP Passivation Layer.

In this letter, we demonstrate that a significant improvement of optical performance of InAs nanowires can be achieved by capping the core InAs nanowires with a thin InP shell, which successfully passivates the surface states reducing the rate of non-radiative recombination. The improvements have been confirmed by detailed photoluminescence measurements, which showed up to ten-fold increase in the intensity of room-temperature photoluminescence from the capped InAs/InP nanowires compared to the sample with ...

A conformal lithium fluoride protection layer on three-dimensional lithium by non-hazardous gaseous reagent Freon.

Research on lithium (Li) metal chemistry has been rapidly gaining momentum nowadays not only because of the appealing high theoretical capacity, but also its indispensable role in the next-generation Li-S and Li-air batteries. However, two root problems of Li metal, namely high reactivity and infinite relative volume change during cycling, bring about numerous other challenges that impede its practical applications. In the past, extensive studies have targeted these two root causes by either improving inter...

Monolithic InGaAs nanowire array lasers on silicon-on-insulator operating at room temperature.

Chip-scale integrated light sources are a crucial component in a broad range of photonics applications. III-V semiconductor nanowire emitters have gained attention as a fascinating approach due to their superior material properties, extremely compact size, and the capability to grow directly on lattice-mismatched silicon substrates. Although there have been remarkable advances in nanowire-based emitters, their practical applications are still in the early stages due to the difficulties in integrating nanowi...

Polarity Control of Heteroepitaxial GaN Nanowires on Diamond.

Group III-nitride materials such as GaN nanowires are characterized by a spontaneous polarization within the crystal. The sign of the resulting sheet charge at the top and bottom facet of a GaN nanowire is determined by the orientation of the wurtzite bilayer of the different atomic species, called N and Ga polarity. We investigate the polarity distribution of heteroepitaxial GaN nanowires on different substrates and demonstrate polarity control of GaN nanowires on diamond. Kelvin Probe Force Microscopy is ...

A Flexible Lithium-Ion Fiber Battery by Regularly Stacking Two-Dimensional Titanium Oxide Nanosheets Hybridized with Reduced Graphene Oxide.

Increasing interest has recently been devoted to developing small, rapid, and portable electronic devices; thus, it is becoming critically important to provide matching light and flexible energy-storage systems to power them. To this end, compared with the inevitable drawbacks of being bulky, heavy, and rigid for traditional planar sandwiched structures, linear fiber-shaped lithium-ion batteries (LIB) have become increasingly important owing to their combined superiorities of miniaturization, adaptability, ...

Optical binding of nanowires.

Multiple scattering of light induces structured interactions, or optical binding forces, between collections of small particles. This has been extensively studied in the case of micro-spheres. However, binding forces are strongly shape dependent: here, we turn our attention to dielectric nanowires. Using a novel numerical model we uncover rich behaviour. The extreme geometry of the nanowires produces a sequence of stationary and dynamic states. In linearly polarized light, thermally stable ladder-like struc...

On the optimization of current injection in AlGaInP core-shell nanowire light-emitting diodes.

Core-shell nanowires offer great potential to enhance the efficiency of light-emitting diodes (LEDs) and expand the attainable wavelength range of LEDs over the whole visible spectrum. Additionally, nanowire LEDs can offer both improved light extraction and emission enhancement if the diameter of the wires is not larger than half the emission wavelength (λ/2). However, AlGaInP nanowire LEDs have so far failed to match the high efficiencies of traditional planar technologies, and the parameters limiting the...

A Hierarchical Phosphorus-Nanobarbed Nanowire Hybrid:Its Structure and Electrochemical Properties.

Nanostructured phosphorus-carbon composites are promising materials for Li-ion and Na-ion battery anodes. A hierarchical phosphorus hybrid, SiC@graphene@P, has been synthesized by chemical vapor deposition of phosphorous on the surfaces of barbed nanowires, where the barbs are vertically grown graphene nanosheets and the cores are SiC nanowires. A temperature gradient vaporization-condensation method has been used to remove the unhybridized phosphorous particles formed by homogeneous nucleation. The vertica...

High-capacity and Ultrafast Na-ion Storage of Self-supported 3D Porous Antimony Persulfide@graphene Foam Architecture.

The key challenge for high performance sodium-ion batteries is the exploitation of appropriate electrode materials with long cycling stability and high rate capability. Here, we report Sb2S5 nanoparticles (~ 5 nm) uniformly encapsulated in three-dimensional (3D) porous graphene foam, which were fabricated by a facile hydrothermal co-assembly strategy, as a high-performance anode material for sodium-ion batteries. The as-prepared composite can be directly used as electrodes without adding binder or current c...

Human immune protein C1q selectively disaggregates carbon nanotubes.

We atomistically compute the change in free energy upon binding of the globular domain of the complement protein C1q to carbon nanotubes (CNTs) and graphene in solution. Our modeling results imply that C1q is able to disaggregate and disperse bundles of large diameter multi-walled CNTs but not those of thin single-walled CNTs, and we validate this prediction with experimental observations. The results support the view of a strong binding, with potential implications for the understanding of the immune respo...

The nature of electron mobility in hybrid perovskite CH3NH3PbI3.

CH3NH3PbI3 is one of the most promising candidates for cheap and high-efficiency solar cells. One of its unique features is the long carrier diffusion length (> 100 μm), but its carrier mobility is rather modest. The nature of the mobility is unclear. Here, using non-adiabatic wave function dynamics simulations, we show that the random rotations of the CH3NH3 cations play an important role in the carrier mobility. Our previous work showed that the electron and hole wave functions were localized and spatial...

Modulation of electron-phonon coupling in one-dimensionally nanorippled graphene on a macrofacet of 6H-SiC.

Local electron-phonon coupling of a one-dimensionally rippled graphene is studied on a SiC(0001) vicinal substrate. We have characterized local atomic and electronic structures of a periodically nano-rippled graphene (3.4 nm period) prepared on a macrofacet of the 6H-SiC crystal using scanning tunneling microscopy/spectroscopy (STM/STS) and angle-resolved photoelectron spectroscopy. The rippled graphene on the macrofacets distributes homogeneously over the 6H-SiC substrate in a mm scale, and thus replica ba...

Implications of occupational disorder on ion mobility in Li4Ti5O12 battery materials.

Lithium-titanium-oxide (Li4Ti5O12, LTO) is unique among battery materials due to its exceptional cyclability and high rate capability. This performance is believed to derive at least partly from the occupational disorder introduced via mixed Li/Ti occupancy in the LTO spinel-like structure. We explore the vast configuration space accessible during high-temperature LTO synthesis by Monte Carlo sampling and indeed find lowest-energy structures to be characterized by a high degree of microscopic inhomogeneity....

Molybdenum carbamate nanosheets as a new class of potential phase change materials.

We report, for the first time, the synthesis of large, free-standing, Mo2O2(µ-S)2(Et2dtc)2 (MoDTC) nanosheets (NSs), which exhibit an electron-beam induced crystalline-to-amorphous phase transition. Both electron beam ionization and femtosecond (fs) optical excitation induce the phase transition, which is size-, morphology- and composition-preserving. Resulting NSs are the largest, free standing regularly-shaped two-dimensional amorphous nanostructures made to date. More importantly, amorphization is accom...

Spatiotemporal Evolution of Coherent Elastic Strain Waves in a Single MoS2 Flake.

We use bright-field imaging in an ultrafast electron microscope to spatiotemporally map the evolution of photoexcited coherent strain waves in a single, micrometer-size flake of MoS2. Following in situ femtosecond photoexcitation, we observe individual wave trains emerge from discrete nanoscale morphological features and propagate in-plane along specific wave vectors at approximately the speed of sound (7 nm/ps). Over the span of several-hundred picoseconds, the 50-GHz wave trains (20-ps periods) are observ...

Novel focused ultrasound gene therapy approach non-invasively restores dopaminergic neuron function in a rat Parkinson's disease model.

Therapies capable of decelerating, or perhaps even halting, neurodegeneration in Parkinson's disease (PD) remain elusive. Clinical trials of PD gene therapy testing the delivery of neurotrophic factors, such as the glial cell-line derived neurotrophic factor (GDNF), have been largely ineffective due to poor vector distribution throughout the diseased regions in the brain. In addition, current delivery strategies involve invasive procedures that obviate the inclusion of early-stage patients who are most like...


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