1,046 research outputs found
Malnutrition and bilateral central retinal vein occlusion in a young woman: a case report
Introduction: Can vitamin B12 and folate deficiency cause central retinal vein occlusion? We
conducted a literature search to find out whether nutritional deficiency of vitamin B12 and folate
can lead to impaired vision.
Case presentation: The patient in the article presented in an eye-casualty department in the
North East of England with gradual painless visual loss over six weeks. She was found to have
bilateral central retinal vein occlusion with significant anaemia and vitamin B12 and folate deficiency.
Conclusion: Vitamin B12 and folate deficiency can lead to elevated levels of homocysteine. We
found a large amount of published data relating central retinal vein occlusion to elevated
homocysteine levels, but there was a lack of conclusive evidence for this association Patients should
be asked about their dietary history where a thrombotic event is suspected or confirmed
An electron jet pump: The Venturi effect of a Fermi liquid
A three-terminal device based on a two-dimensional electron system is
investigated in the regime of non-equilibrium transport. Excited electrons
scatter with the cold Fermi sea and transfer energy and momentum to other
electrons. A geometry analogous to a water jet pump is used to create a jet
pump for electrons. Because of its phenomenological similarity we name the
observed behavior "electronic Venturi effect".Comment: Journal of Applied Physics Special Topic: Plenary and Invited Papers
from the 30th International Conference on the Physics of Semiconductors,
Seoul, Korea, 2010; http://link.aip.org/link/?JAP/109/10241
Polytriazolium poly(ionic liquid) bearing triiodide anions : synthesis, basic properties and electrochemical behaviors
Data integration for plant genomics - exemplars from the integration of Arabidopsis thaliana databases
Relaxation of hot electrons in a degenerate two-dimensional electron system: transition to one-dimensional scattering
The energy relaxation channels of hot electrons far from thermal equilibrium
in a degenerate two-dimensional electron system are investigated in transport
experiments in a mesoscopic three-terminal device. We observe a transition from
two dimensions at zero magnetic field to quasi--one-dimensional scattering of
the hot electrons in a strong magnetic field. In the two-dimensional case
electron-electron scattering is the dominant relaxation mechanism, while the
emission of optical phonons becomes more and more important as the magnetic
field is increased. The observation of up to 11 optical phonons emitted per hot
electron allows us to determine the onset energy of LO phonons in GaAs at
cryogenic temperatures with a high precision, \eph=36.0\pm0.1\,meV. Numerical
calculations of electron-electron scattering and the emission of optical
phonons underline our interpretation in terms of a transition to
one-dimensional dynamics.Comment: 15 pages, 9 figure
Quantum interference and phonon-mediated back-action in lateral quantum dot circuits
Spin qubits have been successfully realized in electrostatically defined,
lateral few-electron quantum dot circuits. Qubit readout typically involves
spin to charge information conversion, followed by a charge measurement made
using a nearby biased quantum point contact. It is critical to understand the
back-action disturbances resulting from such a measurement approach. Previous
studies have indicated that quantum point contact detectors emit phonons which
are then absorbed by nearby qubits. We report here the observation of a
pronounced back-action effect in multiple dot circuits where the absorption of
detector-generated phonons is strongly modified by a quantum interference
effect, and show that the phenomenon is well described by a theory
incorporating both the quantum point contact and coherent phonon absorption.
Our combined experimental and theoretical results suggest strategies to
suppress back-action during the qubit readout procedure.Comment: 25 pages, 8 figure
Magneto-electrical subbands of freely suspended quantum point contacts
We present a versatile design of freely suspended quantum point contacts with
particular large one-dimensional subband quantization energies of up to 10meV.
The nanoscale bridges embedding a two-dimensional electron system are
fabricated from AlGaAs/GaAs heterostructures by electron-beam lithography and
etching techniques. Narrow constrictions define quantum point contacts that are
capacitively controlled via local in-plane side gates. Employing transport
spectroscopy, we investigate the transition from electrostatic subbands to
Landau-quantization in a perpendicular magnetic field. The large subband
quantization energies allow us to utilize a wide magnetic field range and
thereby observe a large exchange splitted spin-gap of the two lowest
Landau-levels
Direct evidence of ZnO morphology modification via the selective adsorption of ZnO-binding peptides
Biomolecule-mediated ZnO synthesis has great potential for the tailoring of ZnO morphology for specific application in biosensors, window materials for display and solar cells, dye-sensitized solar cells (DSSCs), biomedical materials, and photocatalysts due to its specificity and multi-functionality. In this contribution, the effect of a ZnO-binding peptide (ZnO-BP, G-12: GLHVMHKVAPPR) and its GGGC-tagged derivative (GT-16: GLHVMHKVAPPRGGGC) on the growth of ZnO crystals expressing morphologies dependent on the relative growth rates of (0001) and (10 (1) over bar0) planes of ZnO have been studied. The amount of peptide adsorbed was determined by a depletion method using oriented ZnO films grown by Atomic Layer Deposition (ALD), while the adsorption behavior of G-12 and GT-16 was investigated using XPS and a computational approach. Direct evidence was obtained to show that (i) both the ZnO-BP identified by phage display and its GGGC derivative (GT-16) are able to bind to ZnO and modify crystal growth in a molecule and concentration dependent fashion, (ii) plane selectivity for interaction with the (0001) versus the (10 (1) over bar0) crystal planes is greater for GT-16 than G-12; and (iii) specific peptide residues interact with the crystal surface albeit in the presence of charge compensating anions. To our knowledge, this is the first study to provide unambiguous and direct quantitative experimental evidence of the modification of ZnO morphology via (selective and nonselective) adsorption-growth inhibition mechanisms mediated by a ZnO-BP identified from phage display libraries
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