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PubMed Journal Database | Nano letters RSS

14:18 EDT 29th June 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 3,000+ from Nano letters

Adiabatic Edge Channel Transport in a Nanowire Quantum Point Contact Register.

We report on a prototype device geometry where a number of quantum point contacts are connected in series in a single quasi-ballistic InAs nanowire. At finite magnetic field the backscattering length is increased up to the micron-scale and the quantum point contacts are connected adiabatically. Hence, several input gates can control the outcome of a ballistic logic operation. The absence of backscattering is explained in terms of selective population of spatially separated edge channels. Evidence is provide...

Tip Enhanced Raman Spectroscopic Imaging of Individual Carbon Nanotubes with Sub-nanometer Resolution.

Individual carbon nanotubes (CNTs) have been investigated by tip enhanced Raman spectroscopy (TERS) using silver tips on the Ag(111) substrate with a low-temperature ultrahigh-vacuum scanning tunneling microscope. Thanks to the strong and highly localized plasmonic field offered by the silver nanogap, the spatial resolution of TERS on CNTs is driven down to about 0.7 nm. Such a high spatial resolution allows to visualize in real space the spatial extent of the defect-induced D-band scattering, to track the ...

Asymmetric hysteresis for probing Dzyaloshinskii-Moriya interaction.

The interfacial Dzyaloshinskii-Moriya interaction (DMI) is intimately related to the prospect of superior domain-wall dynamics and the formation of magnetic skyrmions. Although some experimental efforts have been recently proposed to quantify these interactions and the underlying physics, it is still far from trivial to address the interfacial DMI. Inspired by the reported tilt of the magnetization of the side edge of a thin film structure, we here present a quasi-static, straightforward measurement tool. B...

Giant Faraday rotation of high-order plasmonic modes in graphene-covered nanowires.

Plasmonic Faraday rotation in nanowires manifests itself in the rotation of the spatial intensity distribution of high-order surface plasmon polariton (SPP) modes around the nanowire axis. Here we predict theoretically the giant Faraday rotation for SPP propagating on graphene-coated magneto-optically active nanowires. Upon the reversal of the external magnetic field pointing along the nanowire axis some high-order plasmonic modes may be rotated by up to ∽ 100 degrees on scale of about 500 nm at mid-infra...

Nanosecond-timescale low error switching of in-plane magnetic tunnel junctions through dynamic Oersted-field assisted spin-Hall effect.

We investigate fast-pulse switching of in-plane-magnetized magnetic tunnel junctions (MTJs) within 3-terminal devices in which spin-transfer torque is applied to the MTJ by the giant spin Hall effect. We measure reliable switching, with write error rates down to 10(-5), using current pulses as short as just 2 ns in duration. This represents the fastest reliable switching reported to date for any spin-torque-driven magnetic memory geometry, and corresponds to a characteristic time scale that is significantly...

Highly Integrated Nano-Platform for Breaking the Barrier between Chemotherapy and Immunotherapy.

Fighting metastasis is a major challenge in cancer therapy and stimulation of the immune system is of particular importance in the treatment of metastatic cancers. Here, an integrated theranostic nano-platform was developed for the efficient treatment of highly metastatic tumors. Versatile functions including "And" logically controlled drug release, prolonged circulation time, tumor targeting, and anti-metastasis were integrated into doxorubicin (DOX) loaded, highly integrated mesoporous silica nanoparticle...

Formation of second-generation nanoclusters on metal nanoparticles driven by reactant gases.

Heterogeneous catalysis occurs at the interface of a solid catalyst and reactants. The structure of metal catalyst nanoparticles at the metal-gas interface is a key factor that determines catalytic selectivity and activity. Here we report that second-generation nanoclusters are formed on the surfaces of the initial catalyst nanoparticles as a result of interaction with the reactant molecules when these metal nanoparticles are in a gas phase at Torr pressure or higher at room temperature. The formation of th...

Self-Healable Sensors based Nanoparticles for Detecting Physiological Markers via Skin and Breath: Towards Disease Prevention via Wearable Devices.

Flexible and wearable electronic sensors are useful in the early diagnosis after continuously monitoring an individual's health state. Sampling of volatile organic compounds (VOCs) derived from human breath/skin or monitoring abrupt changes in heart-beat/breath rate should allow non-invasive monitoring of disease states at an early stage. Nevertheless, for many reported wearable sensing devices, interaction with the human body can lead incidentally to unavoidable scratches and/or mechanical cuts that lead t...

Nanowires and electrical stimulation synergistically improve functions of hiPSC cardiac spheroids.

The advancement of human induced pluripotent stem cell-derived cardiomyocyte (hiPSC-CM) technology has shown promising potential to provide a patient-specific, regenerative cell therapy strategy to treat cardiovascular disease. Despite the progress, the unspecific, underdeveloped phenotype of hiPSC-CMs has shown arrhythmogenic risk and limited functional improvements after transplantation. To address this, tissue engineering strategies have utilized both exogenous and endogenous stimuli to accelerate the de...

General Thermal Texturization Process of MoS2 for Efficient Electrocatalytic Hydrogen Evolution Reaction.

Molybdenum disulfide (MoS2) has been widely examined as a catalyst containing no precious metals for the hydrogen evolution reaction (HER); however, these examinations have utilized synthesized MoS2 because the pristine MoS2 mineral is known to be a poor catalyst. The fundamental challenge with pristine MoS2 is the inert HER activity of the predominant (0001) basal surface plane. In order to achieve high HER performance with pristine MoS2, it is essential to activate the basal plane. Here, we report a gener...

High volumetric capacity three-dimensionally sphere-caged secondary battery anodes.

High volumetric energy density secondary batteries are important for many applications, which has led to considerable efforts to replace the low volumetric capacity graphite-based anode common to most Li-ion batteries with a higher energy density anode. Because most high capacity anode materials expand significantly during charging, such anodes must contain sufficient porosity in the discharged state to enable the expansion, yet not excess porosity, which lowers the overall energy density. Here, we present ...

High-Performance All-Solid-State Lithium-Sulfur Battery Enabled by a Mixed-Conductive Li2S Nanocomposite.

All-solid-state lithium-sulfur batteries (ASSLSBs) using highly conductive sulfide-based solid electrolytes suffer from low sulfur utilization, poor cycle life and low rate performance due to the huge volume change of the electrode and the poor electronic and ionic conductivities of S and Li2S. The most promising approach to mitigate these challenges lies in the fabrication of a sulfur nanocomposite electrode consisting of a homogeneous distribution of nano-sized active material, solid electrolyte and carbo...

Correction to Anisotropic Electron-Photon and Electron-Phonon Interactions in Black Phosphorus.

Strain-induced Isostructural and Magnetic Phase Transitions in Monolayer MoN2.

The change of bonding status, typically occurring only in chemical processes, could dramatically alter the material properties. Here, we show that a tunable breaking and forming of a diatomic bond can be achieved through physical means, i.e., by a moderate biaxial strain, in the newly discovered MoN2 two-dimensional (2D) material. Based on first-principles calculations, we predict that as the lattice parameter is increased under strain, there exists an isostructural phase transition at which the N-N distanc...

Enhanced precision of nanoparticle phototargeting in vivo at a safe irradiance.

A large proportion of the payload delivered by nanoparticulate therapies is deposited not in the desired target destination but in off-target locations such as the liver and spleen. Here, we demonstrate that phototargeting can improve the specific targeting of nanoparticles to tumors. The combination of efficient triplet-triplet annihilation upconversion (TTA-UC) and Förster resonance energy transfer (FRET) processes allowed in vivo phototargeting at a safe irradiance (200 mW/cm(2)) over a short period (5 ...

High-Resolution p-type Metal Oxide Semiconductor Nanowire Array as an Ultrasensitive Sensor for Volatile Organic Compounds.

The development of high-performance volatile organic compound (VOC) sensor based on a p-type metal oxide semiconductor (MOS) is one of the important topics in gas sensor research because of its unique sensing characteristics, namely, rapid recovery kinetics, low temperature dependence, high humidity or thermal stability, and high potential for p-n junction applications. Despite intensive efforts made in this area, the applications of such sensors are hindered because of drawbacks related to the low sensitiv...

Bright UV single photon emission at point defects in h-BN.

To date, quantum sources in the ultraviolet (UV) spectral region have been obtained only in semiconductor quantum dots. Color centers in wide bandgap materials may represent a more effective alternative. However, the quest for UV quantum emitters in bulk crystals faces the difficulty of combining an efficient UV excitation/detection optical setup with the capability of addressing individual color centers in potentially highly defective materials. In this work we overcome this limit by employing an original ...

Simultaneous chemical and refractive index sensing in 1-2.5 μm near-infrared wavelength range on nanoporous gold disks.

Near-infrared (NIR) absorption spectroscopy provides molecular and chemical information based on overtones and combination bands of the fundamental vibrational modes in the infrared wavelengths. However, the sensitivity of NIR absorption measurement is limited by the generally weak absorption and the relatively poor detector performance compared to other wavelength ranges. To overcome these barriers, we have developed a novel technique to simultaneously obtain chemical and refractive index sensing in 1-2.5 ...

High-energy surface and volume plasmons in nanopatterned sub-10-nm aluminum nanostructures.

In this work, we use electron energy-loss spectroscopy to map the complete plasmonic spectrum of aluminum nanodisks with diameters ranging from 3 nm to 120 nm fabricated by high-resolution electron-beam lithography. Our nanopatterning approach allows us to produce localized surface plasmon resonances across a wide spectral range spanning 2-8 eV. Electromagnetic simulations using the finite element method support the existence of dipolar, quadrupolar and hexapolar surface plasmon modes as well as centrosymme...

Quantum interference in graphene nanoconstrictions.

We report quantum interference effects in the electrical conductance of chemical vapour deposited graphene nanoconstrictions fabricated using feedback controlled electroburning. The observed multi-mode Fabry-Pérot interferences can be attributed to reflections on potential steps inside the channel. Sharp anti-resonance features with a Fano line shape are observed. Theoretical modelling reveals that these Fano resonances are due to localised states inside the constriction, which couple to the delocalised st...

Template Assisted Direct growth of 1Td/in(2) Bit patterned Media.

We present a method for growing bit patterned magnetic recording media using directed growth of sputtered granular perpendicular magnetic recording media. The grain nucleation is templated using an epitaxial seed layer which contains Pt pillars separated by amorphous metal oxide. The scheme enables the creation of both templated data and servo regions suitable for high density hard disk drive operation. We illustrate the importance of using a process that is both topographically and chemically driven to ach...

Nondestructive measurement of the evolution of layer-specific mechanical properties in sub-10 nm bilayer films.

We use short wavelength extreme ultraviolet light to independently measure the mechanical properties of disparate layers within a bilayer film for the first time, with single-monolayer sensitivity. We show that in Ni/Ta nanostructured systems, while their density ratio is not significantly changed from that expected in bulk, their elastic properties are significantly modified, where nickel softens while tantalum stiffens, relative to their bulk counterparts. In particular, the presence or absence of the Ta ...

Topologically-protected metallic states induced by a one-dimensional extended defect in the bulk of a 2D topological insulator.

We report {\textit ab initio} calculations showing that a one-dimensional extended defect generates topologically-protected metallic states immersed in the bulk of two-dimensional topological insulators. We find that a narrow extended defect, composed of periodic units consisting of one octagonal and two pentagonal rings (a 558 extended defect), embedded in the hexagonal bulk of a bismuth bilayer, introduces two pairs of one-dimensional counter propagating helical-fermion electronic bands with the opposite ...

Unlocking the Origin of Superior Performance of a Si-Ge Core-Shell Nanowire Quantum Dot Field Effect Transistor.

The sustained advancement in semiconducting core-shell nanowire technology has unlocked a tantalizing route for making next generation field effect transistor (FET). Understanding how to control carrier mobility of these nanowire channels by applying a gate field is the key to developing a high performance FET. Herein, we have identified the switching mechanism responsible for the superior performance of a Si-Ge core-shell nanowire quantum dot FET over its homogeneous Si counterpart. A quantum transport app...

Band alignment and minigaps in monolayer MoS2-graphene van der Waals heterostructures.

Two-dimensional layered MoS2 shows great potential for nanoelectronic and optoelectronic devices due to its high photosensitivity, which is the result of its indirect to direct band gap transition when the bulk dimension is reduced to a single monolayer. Here, we present an exhaustive study of the band alignment and relativistic properties of a van der Waals heterostructure formed between single layers of MoS2 and graphene. A sharp, high-quality MoS2-graphene interface was obtained and characterized by micr...


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