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PubMed Journal Database | Nano letters RSS

17:42 EDT 31st July 2014 | 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 1,900+ from Nano letters

1055931

Metal-Catalyzed Electroless Etching of Silicon in Aerated HF/H2O Vapor for Facile Fabrication of Silicon Nanostructures.

Inspired by metal corrosion in air, we demonstrate that metal-catalyzed electroless etching (MCEE) of silicon can be performed simply in aerated HF/H2O vapor for facile fabrication of three-dimensional silicon nanostructures such as silicon nanowires (SiNW) arrays. Compared to MCEE commonly performed in aqueous HF solution, the present pseudo gas phase etching offers exceptional simplicity, flexibility, environmental friendliness, and scalability for the fabrication of three-dimensional silicon nanostructur...

1055730

Solid-State Semiconductor Cryocooler Based on CdS Nanobelts.

We demonstrate the laser cooling of silicon on insulator (SOI) substrate using CdS nanobelts. The local temperature change of the SOI substrate exactly beneath the CdS nanobelts is deduced from the ratio of the Stokes and anti-Stokes Raman intensities from the Si layer on the top of the SOI substrate. We have achieved a 30 K and 20 K net cooling starting from 290 K under a 3.8 mW 514 nm and a 4.4 mW 532 nm pumping, respectively. In contrast, laser heating effect has been observed pumped by 502 nm and 488 nm...

Friday 21st December 1054

Spatiotemporal Intracellular Nitric Oxide Signaling Captured using Internalized, Near Infrared Fluorescent Carbon Nanotube Nanosensors.

Fluorescent nanosensor probes have suffered from limited molecular recognition and a dearth of strategies for spatial-temporal operation in cell culture. In this work, we spatially imaged the dynamics of nitric oxide (NO) signaling, important in numerous pathologies and physiological functions, using intracellular near-infrared fluorescent single-walled carbon nanotubes (SWCNT). The observed spatial-temporal NO signaling gradients clarify and refine the existing paradigm of NO signaling based on averaged lo...

Thursday 23rd August 1054

All-Color Plasmonic Nanolasers with Ultralow Thresholds: Auto-tuning Mechanism for Single-Mode Lasing.

We report on the first demonstration of broadband tunable, single-mode plasmonic nanolasers (spasers) emitting in the full visible spectrum. These nanolasers are based on a single metal-oxide-semiconductor nanostructure platform comprising of InGaN/GaN semiconductor nanorods supported on an Al2O3-capped epitaxial Ag film. In particular, all-color lasing in sub-diffraction plasmonic resonators is achieved via a novel mechanism based on a property of weak size dependence inherent in spasers. Moreover, we have...

1053563

Bending-induced Symmetry Breaking of Lithiation in Germanium Nanowires.

From signal transduction of living cells to oxidation and corrosion of metals, mechanical stress intimately couples with chemical reactions, regulating these biological and physiochemical processes. The coupled effect is particularly evident in electrochemical lithiation/delithiation cycling of high-capacity electrodes, such as silicon (Si), where on the one hand lithiation-generated stress mediates lithiation kinetics, and on the other electrochemical reaction rate regulates stress generation and mechanica...

Tuesday 23rd May 1053

Size Dependent Effects of Nanoparticles on Enzymes in the Blood Coagulation Cascade.

Nanoparticles (NPs) are increasingly used in diagnostic and drug delivery. After entering the blood stream a protein corona will form around NPs. The size and curvature of NPs is one of the major characteristics affecting the composition of bound protein in the corona. Key initiators of the intrinsic pathway of blood coagulation, the contact activation complex, (Kallikrein, Factor XII and High Molecular Weight Kininogen) have previously been identified on NPs surfaces. We show that the functional impact of...

Monday 20th March 1053

An advanced lithium-ion battery based on a graphene anode and a lithium iron phosphate cathode.

We report an advanced lithium-ion battery based on a graphene ink anode and a lithium iron phosphate cathode. By carefully balancing the cell composition and suppressing the initial irreversible capacity of the anode in the round of few initial cycles, we demonstrate an optimal battery performance in terms of specific capacity, i.e. 165 mAhg-1, of an estimated energy density of about 190 Wh kg-1 and a stable operation for over 80 charge-discharge cycles. The components of the battery are potentially scalabl...

Monday 16th January 1053

Cytocompatibility and cellular internalization mechanisms of SiC/SiO2 Nanowires.

First evidence of in vitro cytocompatibility of SiC/SiO2 core shell nanowires is reported. Different internalization mechanisms by adenocarcinomic alveolar basal epithelial cells, monocytic cell line derived from an acute monocytic leukemia, breast cancer cells and normal human-derma fibroblasts are shown. The internalization occurs mainly for macropinocytosis and sporadically by direct penetration in all cell models considered, whereas it occurred for phagocytosis only in monocytic leukemia cells. The cyto...

1052971

Interdiffusion Induced Exchange Coupling of L10-FePd/α-Fe Magnetic Nanocomposites.

One-pot synthesis of FePd and FePd/Fe2O3 (core/shell) nanoparticles via interdiffusion is reported for the first time. It was found that the size of FePd particles and Fe2O3 shell thickness could be controlled by the ligand and iron precursor amounts, respectively. These FePd/Fe2O3 particles can be reductively annealed at 500 °C to produce exchanged coupled L10-FePd/α-Fe magnetic nanocomposites. The effect of the phosphine ligand on magnetic characteristics of synthesized particles and final annealed nano...

1052866

A nanoscale demonstration of hydrogen atom spill-over and surface diffusion across silica using the kinetics of CO2 methanation catalyzed on spatially separate Pt and Co nanoparticles.

Hydrogen spillover is of great importance to understanding many phenomena in heterogeneous catalysis, and has long been controversial. Here we exploit well-defined nanoparticles to demonstrate its occurrence through evaluation of CO2 methanation kinetics. Combining platinum and cobalt nanoparticles causes a substantial increase in reaction rate; but increasing the spatial separation between discrete cobalt and platinum entities results in a dramatic ~50% drop in apparent activation energy, symptomatic of H-...

Sunday 8th November 1051

Epitaxially Aligned Cuprous Oxide Nanowires for All-Oxide, Single-Wire Solar Cells.

As a p-type semiconducting oxide that can absorb visible light, cuprous oxide (Cu2O) is an attractive material for solar energy conversion. This work introduces a high-temperature, vapor-phase synthesis that produces faceted Cu2O nanowires that grow epitaxially along the surface of a lattice-matched, single-crystal MgO substrate. Individual wires were then fabricated into single-wire, all-oxide diodes and solar cells using low-temperature atomic layer deposition (ALD) of TiO2 and ZnO films to form the heter...

Sunday 2nd August 1051

Wide Field Super-Resolution Surface Imaging through Plasmonic Structured Illumination Microscopy.

We experimentally demonstrate a wide field surface plasmon (SP) assisted super-resolution imaging technique, plasmonic structured illumination microscopy (PSIM), by combining tunable SP interference (SPI) with structured illumination microscopy (SIM). By replacing the laser interference fringes in conventional SIM with SPI patterns, PSIM exhibits greatly enhanced resolving power thanks to the unique properties of SP waves. This PSIM technique is a wide field, surface super-resolution imaging technique with...

1050940

A simple self-calibrating method to measure the height of fluorescent molecules and beads at nanoscale resolution.

We describe a simple self-calibrating technique, incident-beam interference sweeping (IBIS), for measuring the height of fluorescent labels. Using a tilted back-reflecting mirror and a scanning laser beam, a modulated fluorescence emission allows height determination of a label from a surface with a resolution of ~3 nanometer. In addition, we show that the absolute distance of a label from the top-mounted mirror can be determined with a resolution of a few tens of nanometers over a micrometer range.

1050818

Defect-Free, Size-Tunable Graphene for High-Performance Lithium Ion Battery.

The scalable preparation of graphene in control of its structure would significantly improve its commercial viability. Despite intense research in this area, the size control of defect-free graphene (df-G) without any trace of oxidation or structural damage remains a key challenge. Here, we propose a new scalable route for generating df-G with a controllable size of sub-micron to micron through sequential insertion of potassium and pyridine at low temperature. Structural and chemical analyses confirm that t...

1050813

Carbon Nanotube Deformation and Collapse under Metal Contacts.

In carbon nanotube transistors, typically part of the nanotube is covered by a metal contact. This covered region plays an important role due to the significant electron transfer length. Here we predict that capillary and van der Waals forces cause the nanotube to deform or even collapse under the metal. Nanotubes are known to collapse when their diameters are above some critical value around 4 nm. Under the metal, we find that spontaneous collapse occurs for diameters down to ∼1.5-1.6 nm, close to the ra...

Thursday 25th December 1050

Temperature Gated Thermal Rectifier for Active Heat Flow Control.

Active heat flow control is essential for broad applications of heating, cooling and energy conversion. Like electronic devices developed for the control of electric power, it is very desirable to develop advanced all-thermal solid-state devices that actively control heat flow, without consuming other forms of energy. Here we demonstrate temperature-gated thermal rectification using vanadium dioxide beams, in which the environmental temperature actively modulates asymmetric heat flow. In this three terminal...

Saturday 27th April 1049

Correlated electrical and optical analysis of single nanoparticles and biomolecules on a nanopore-gated optofluidic chip.

The analysis of individual biological nanoparticles has significantly advanced our understanding of fundamental biological processes, but is also rapidly becoming relevant for molecular diagnostic applications in the emerging field of personalized medicine. Both optical and electrical methods for detection and analysis of single biomolecules have been developed, but they are generally not used in concert and in suitably integrated form to allow for multimodal analysis with high throughput. Here, we report o...

1048862

Hierarchical Porous Carbon by Ultrasonic Spray Pyrolysis Yields Stable Cycling in Lithium-Sulfur Battery.

Utilizing the unparalleled theoretical capacity of sulfur reaching 1675 mAh/g, lithium-sulfur (Li-S) batteries have been counted as promising enablers of future lithium ion battery (LIB) applications requiring high energy densities. Nevertheless, most sulfur electrodes suffer from insufficient cycle lives originating from fatal dissolution of lithium polysulfides. As a fundamental solution to this chronic shortcoming, herein, we introduce a hierarchical porous carbon structure in which meso- and macro-pores...

1048448

Correction to Observation of Multiple, Identical Binding Sites in the Exchange of Carboxylic Acid Ligands with CdS Nanocrystals.

1047610

Bandgap, Mid-Gap States and Gating Effects in MoS2.

The discovery of graphene has put the spotlight on other layered materials including transition metal dichalcogenites (TMD) as building blocks for novel heterostructures assembled from stacked atomic layers. Molybdenum disulfide, MoS2, a semiconductor in the TMD family, with its remarkable thermal and chemical stability and high mobility, has emerged as a promising candidate for post-silicon applications such as switching, photonics, and flexible electronics. Since these rely on controlling the position of...

1047524

Wrinkling of Atomic Planes in Ultrathin Au Nanowires.

A detailed understanding of structure and stability of nanowires is critical for applications. Atomic resolution imaging of ultrathin single crystalline Au nanowires us-ing aberration-corrected microscopy reveals an intriguing relaxation whereby the atoms in the close-packed atomic planes normal to the growth direction are displaced in the ax-ial direction leading to wrinkling of the (111) atomic plane normal to the wire axis. First principles calculations of the structure of such nanowires confirm this wri...

1046644

Morphing a plasmonic nanodisk into a nanotriangle.

We morph a silver nanodisk into a nanotriangle by producing a series of nanoparticles with electron beam lithography. Using electron energy loss spectroscopy (EELS) we map out the plasmonic eigenmodes, and trace the evolution of edge and film modes during morphing. Our results suggest that disk modes, characterized by angular order, can serve as a suitable basis for other nanoparticle geometries, and are subject to resonance energy shifts and splittings, as well as to hybridization upon morphing. Similar to...

1046524

Ideal Graphene/Silicon Schottky Junction Diodes.

The proper understanding of semiconductor devices begins at the metal-semiconductor interface. The metal/semiconductor interface itself can also be an important device, as Schottky junctions often forms when the doping in the semiconductors is low. Here, we extend the analysis of metal-silicon Schottky junctions by using graphene, an atomically thin semimetal. We show that a fundamentally new transport model is needed to describe the graphene-silicon Schottky junction. While the current-voltage behavior fol...

1043549

Inverse Opal-Inspired, Nanoscaffold Battery Separators: A New Membrane Opportunity for High-Performance Energy Storage Systems.

The facilitation of ion/electron transport, along with ever-increasing demand for high-energy density, is a key to boosting the development of energy storage systems such as lithium-ion batteries. Among major battery components, separator membranes have not been the center of attention compared to other electrochemically active materials, despite their important roles in allowing ionic flow and preventing electrical contact between electrodes. Here, we present a new class of battery separator based on inver...

1043545

Exquisite Sequence Selectivity with Small Conditional RNAs.

Dynamic RNA nanotechnology based on programmable hybridization cascades with small conditional RNAs (scRNAs) offers a promising conceptual framework for engineering programmable conditional regulation in vivo. While single-base substitution (SBS) somatic mutations and single-nucleotide polymorphisms (SNPs) are important markers and drivers of disease, it is unclear whether synthetic RNA signal transducers are sufficiently programmable to accept a cognate RNA input while rejecting single-nucleotide sequence...


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