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Query: EC:6.2.1.1 (ACS)
 78,556 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A patient presented with an acute inferior myocardial infarction. Coronary angiography in the acute stage revealed total occlusion of the right coronary artery. Reperfusion was obtained after intracoronary infusion of 250,000 units of streptokinase. Angioplasty was subsequently performed because of a high grade residual stenosis. An 8-French right Judkins guiding catheter with a single side hole (USCI), a 3.0 mm balloon dilatation catheter (ACS), and a 0.018 high torque floppy guide wire (ACS) were used. After successful angioplasty angiography was repeated with the guide wire in the RCA, but the balloon was withdrawn into the guiding catheter. After injection of contrast, it was impossible to withdrawn the balloon catheter out of the guiding catheter. Fluoroscopy revealed extrusion of the balloon through the side hole in the guiding catheter.
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PMID:Inadvertant balloon extrusion through a side hole in a guiding catheter. 395 42

We investigate the role of conformational disorder and intermolecular interactions on the electronic structure of amorphous clusters of polyfluorenes. Classical molecular dynamics simulations are used to determine probable molecular geometries and chain packing, and first-principles density functional theory calculations are employed to determine electronic structure and orbital localization properties. Intramolecular and intermolecular effects are disentangled by contrasting results for densely packed oligomer clusters and for ensembles of isolated oligomers with the same intramolecular geometries. Our simulations show that intermolecular disorder allows for nearly planar configurations of interacting fluorenes compared to the isolated molecules. This rationalizes the experimentally detected formation of the planar crystalline morphologies that frequently accompany twisted glassy configurations in fluorene films. The energy gap (HOMO-LUMO gap) significantly decreases for planar configurations. The electron and hole orbital energies are strongly dependent on both torsional angles and intermolecular interactions. This leads to strong localization of electronic states in amorphous polymer aggregates, which is analyzed by examining the respective orbital participation ratios. Notably, the energies of unoccupied levels show stronger dependence on the conformational disorder, compared to that of occupied levels. This results in the more probable formation of trap states near the edge of the conduction band than near the valence band.
ACS Nano 2008 Jul
PMID:Electronic structure of self-assembled amorphous polyfluorenes. 1920 5

We use a coarse-grained numerical simulation to design a synthetic membrane with stable pores that can be controllably opened and closed. Specifically, we use dissipative particle dynamics to probe the interactions between lipid bilayer membranes and nanoparticles. The particles are nanoscopic Janus beads that comprise both hydrophobic and hydrophilic portions. We demonstrate that when the membrane rips and forms a hole due to an external stress, these nanoparticles diffuse to the edge of the hole and form a stable pore, which persists after the stress is released. Once the particle-lined pore is formed, a small increase in membrane tension readily reopens the pore, allowing transport through the membrane. Besides the application of an external force, the membrane tension can be altered by varying, for example, temperature or pH. Thus, the findings provide guidelines for designing nanoparticle-bilayer assemblies for targeted delivery, where the pores open and the cargo is released only when the local environmental conditions reach a critical value.
ACS Nano 2008 Jun
PMID:Harnessing janus nanoparticles to create controllable pores in membranes. 1920 25

Organic hole-transporting molecules were infiltrated into inorganic mesochannels via hexagonally ordered nanopores that are open at the edge side of mesoporous silica (MS) nanolayers prepared using a block copolymer template. This organic-molecule-infiltrated MS nanolayer was used as a hole injection/transport layer for hybrid organic light-emitting devices (HOLED) for improving the device stability. The result showed that the efficiency of HOLED is within reach of that of conventional devices, promising further improvement by the thickness control.
ACS Nano 2008 Jun
PMID:Mesoporous silica nanolayers infiltrated with hole-transporting molecules for hybrid organic light-emitting devices. 1920 31

Subwavelength holes are one of the most important structures in nanophotonics, providing a useful geometry for nanosensing and giving rise to extraordinary transmission when patterned in arrays. Here we theoretically and experimentally examine the optical properties of an individual nanohole in a thin metallic film. In contrast to localized plasmonic nanostructures with their own characteristic resonances, nanoholes provide a site for excitation of the underlying thin film surface plasmons. We show that both hole diameter and film thickness determine the energy of the optical resonance. A theoretical dispersion curve was obtained and verified using spectral measurements of individual nanoholes.
ACS Nano 2008 Jan
PMID:Optical properties of a nanosized hole in a thin metallic film. 1920 44

We study transport and charge control in a gated 4,4'-biphenyl diradical molecular transistor using self-consistent density-functional calculations. We track both electron-like and hole-like conduction and relate it to the field dependence of current-carrying pi-derived states. Owing to the coupling between the two benzene rings, the pi-states become segregated into extended, current-carrying states and localized states. Under application of the source/drain field, along the axis of the molecule, the localized pi-states become split, while the extended states become polarized and screen the field. The localized states act like isolated islands within the molecule--while they make a substantial contribution to the density of states, they make only a small contribution to transport.
ACS Nano 2008 Mar
PMID:The biphenyl molecule as a model transistor. 1920 67

The characteristics of nanoscale excitons--the primary excited states of nanoscale systems like conjugated polymers, molecular aggregates, carbon nanotubes, and nanocrystalline quantum dots--are examined through exploration of model systems. On the basis of a valence bond-type model, an intuition is developed for understanding and comparing nanoscale systems. In particular, electron-hole interactions are examined in detail, showing how and why they affect spectroscopy and properties such as binding energy. The relationship between the bound exciton states and the nanoscale analogue of free carriers (charge-transfer exciton states) is developed. It is shown why the electron and hole act as independent particles in this manifold of states. The outlook for the field is discussed on the basis of the picture developed in the paper, with an emphasis on exciton binding and photodissociation.
ACS Nano 2008 Mar
PMID:Insights into excitons confined to nanoscale systems: electron-hole interaction, binding energy, and photodissociation. 1920 79

We show that light-assisted oxidation with hydrogen peroxide effectively and rapidly opens holes in carbon nanohorn walls and, more importantly, creates abundant oxygenated groups such as carboxylic groups at the hole edges. These oxygenated groups reacted with the protein bovine serum albumin. The obtained conjugates were highly dispersed in phosphate-buffered saline and were taken up by cultured mammalian cells via an endocytosis pathway.
ACS Nano 2007 Nov
PMID:Light-assisted oxidation of single-wall carbon nanohorns for abundant creation of oxygenated groups that enable chemical modifications with proteins to enhance biocompatibility. 1920 76

Solution processable methanofullerene-based solar cells are the most widely studied class of organic photovoltaics (OPVs). The evolution of the electronic properties with solvent vapor annealing (SVA) in polyfluorene-copolymer and [6,6]phenyl-C61-butyric acid methyl ester (PCBM) blended OPVs is studied using various scanning probe techniques: light beam induced current spectroscopy (LBIC), conductive atomic force microscopy (c-AFM), and photoconductive AFM (pc-AFM). We demonstrate that SVA improves the power conversion efficiency by 40% while forming mesoscopic PCBM crystallites and a approximately 3 nm copolymer-rich overlayer at the cathode interface. We find that the large crystallites created during annealing do not directly improve the local performance of the device, but instead attribute the performance improvement to the ripened blend morphology and an increase in the hole mobility of the copolymer in comparison to the unannealed blend. The PCBM-rich aggregates act as a sink for excess PCBM, although excess PCBM is initially required to form the appropriate structural features prior to the annealing process.
ACS Nano 2009 Mar 24
PMID:The role of mesoscopic PCBM crystallites in solvent vapor annealed copolymer solar cells. 1922 11

Photodetection in semiconductors enables digital imaging, spectroscopy, and optical communications. Integration of solution-processed light-sensing materials with a range of substrates offers access to new spectral regimes, the prospect of enhanced sensitivity, and compatibility with flexible electronics. Photoconductive photodetectors based on solution-cast nanocrystals have shown tremendous progress in recent years; however, high-performance reports to date have employed Pb- and Cd-containing materials. Here we report a high-sensitivity (photon-to-electron gain >40), high-speed (video-frame-rate-compatible) photoconductive photodetector based on In(2)S(3). Only by decreasing the energetic depth of hole traps associated with intrinsic vacancies in beta-phase In(2)S(3) were we able to achieve this needed combination of sensitivity and speed. Our incorporation of Cu(+) cations into beta-In(2)S(3)'s spinel vacancies that led to acceptable temporal response in the devices showcases the practicality of incorporating dopants into nanoparticles. The devices are stable in air and under heating to 215 degrees C, advantages rooted in the reliance on the stable inclusion of dopants into available sites instead of surface oxide species.
ACS Nano 2009 Feb 24
PMID:Heavy-metal-free solution-processed nanoparticle-based photodetectors: doping of intrinsic vacancies enables engineering of sensitivity and speed. 1923 59


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