4,424 research outputs found
Effect of TiO2 addition on structure, solubility and crystallisation of phosphate invert glasses for biomedical applications
NOTICE: this is the authorâs version of a work that was accepted for publication in JOURNAL OF NON-CRYSTALLINE SOLIDS. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in JOURNAL OF NON-CRYSTALLINE SOLIDS, [VOL 356, ISSUE 44-49, (2001)] DOI: 10.1016/j.jnoncrysol.2010.03.02
Structural characterization and physical properties of P2O5-CaO-Na2O-TiO2 glasses by Fourier transform infrared, Raman and solid-state magic angle spinning nuclear magnetic resonance spectroscopies.
Phosphate-based glasses have been investigated for tissue engineering applications. This study details the properties and structural characterization of titanium ultra-phosphate glasses in the 55(P(2)O(5))-30(CaO)-(25-x)(Na(2)O)-x(TiO(2)) (0â€xâ€5) system, which have been prepared via melt-quenching techniques. Structural characterization was achieved by a combination of X-ray diffraction (XRD), and solid-state nuclear magnetic resonance, Raman and Fourier transform infrared spectroscopies. Physical properties were also investigated using density, degradation and ion release studies; additionally, differential thermal analysis was used for thermal analysis of these glasses. The results show that with the addition of TiO(2) the density and glass transition temperature increased whereas the degradation and ion release properties are decreased. From XRD data, TiP(2)O(7) and CaP(2)O(6) were detected in 3 and 5 mol.% TiO(2)-containing glasses. Magic angle spinning nuclear magnetic resonance results confirmed that as TiO(2) is incorporated into the glass; the amount of Q(3) increases as the amount of Q(2) consequently decreases, indicating increasing polymerization of the phosphate network. Spectroscopy results also showed that the local structure of glasses changes with increasing TiO(2) content. As TiO(2) is incorporated into the glass, the phosphate connectivity increases, indicating that the addition of TiO(2) content correlates unequivocally with an increase in glass stability
Improving the speed of variational quantum algorithms for quantum error correction
We consider the problem of devising suitable quantum error correction (QEC) procedures for a generic quantum noise acting on a quantum circuit. In general, there is no analytic universal procedure to obtain the encoding and correction unitary gates, and the problem is even harder if the noise is unknown and has to be reconstructed. The existing procedures rely on variational quantum algorithms (VQAs) and are very difficult to train since the size of the gradient of the cost function decays exponentially with the number of qubits. We address this problem using a cost function based on the quantum Wasserstein distance of order 1 (QW1). At variance with other quantum distances typically adopted in quantum information processing, QW1 lacks the unitary invariance property which makes it a suitable tool to avoid getting trapped in local minima. Focusing on a simple noise model for which an exact QEC solution is known and can be used as a theoretical benchmark, we run a series of numerical tests that show how, guiding the VQA search through the QW1, can indeed significantly increase both the probability of a successful training and the fidelity of the recovered state, with respect to the results one obtains when using conventional approaches
Quantum-mechanical effects in photoluminescence from thin crystalline gold films
Luminescence constitutes a unique source of insight into hot carrier
processes in metals, including those in plasmonic nanostructures used for
sensing and energy applications. However, being weak in nature, metal
luminescence remains poorly understood, its microscopic origin strongly
debated, and its potential for unravelling nanoscale carrier dynamics largely
unexploited. Here, we reveal quantum-mechanical effects emanating in the
luminescence from thin monocrystalline gold flakes. Specifically, we present
experimental evidence, supported by first-principles simulations, to
demonstrate its photoluminescence origin when exciting in the interband regime.
Our model allows us to identify changes to the measured gold luminescence due
to quantum-mechanical effects as the gold film thickness is reduced.
Excitingly, such effects are observable in the luminescence signal from flakes
up to 40 nm in thickness, associated with the out-of-plane discreteness of the
electronic band structure near the Fermi level. We qualitatively reproduce the
observations with first-principles modelling, thus establishing a unified
description of luminescence in gold and enabling its widespread application as
a probe of carrier dynamics and light-matter interactions in this material. Our
study paves the way for future explorations of hot-carriers and charge-transfer
dynamics in a multitude of material systems.Comment: Main text 21 pages and 4 figures. Supplemental Information 33 pages
and 17 figure
Detecting Bacterial Cell Viability in Few ”L Solutions from Impedance Measurements on Silicon-Based Biochips
Using two different types of impedance biochips (PS5 and BS5) with ring top electrodes, a distinct change of measured impedance has been detected after adding 1â5 ”L (with dead or live Gram-positive Lysinibacillus sphaericus JG-A12 cells to 20 ”L DI water inside the ring top electrode. We relate observed change of measured impedance to change of membrane potential of L. sphaericus JG-A12 cells. In contrast to impedance measurements, optical density (OD) measurements cannot be used to distinguish between dead and live cells. Dead L. sphaericus JG-A12 cells have been obtained by adding 0.02 mg/mL of the antibiotics tetracycline and 0.1 mg/mL chloramphenicol to a batch with OD0.5 and by incubation for 24 h, 30 âŠC, 120 rpm in the dark. For impedance measurements, we have used batches with a cell density of 25.5 Ă 108 cells/mL (OD8.5) and 270.0 Ă 108 cells/mL (OD90.0). The impedance biochip PS5 can be used to detect the more resistive and less capacitive live L. sphaericus JG-A12 cells. Also, the impedance biochip BS5 can be used to detect the less resistive and more capacitive dead L. sphaericus JG-A12 cells. An outlook on the application of the impedance biochips for high-throughput drug screening, e.g., against multi-drug-resistant Grampositive bacteria, is given
Measurement of prompt D0 and DâŸ0 meson azimuthal anisotropy and search for strong electric fields in PbPb collisions at âsNN=5.02TeV
Measurement of the CP-violating phase Ïs in the Bs0âJ/ÏÏ(1020)âÎŒ+ÎŒâK+Kâ channel in proton-proton collisions at s=13TeV
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