820 research outputs found

    Right ventricular thrombus in a 36-year-old man with Factor v Leiden

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    Factor V Leiden deficiency is the most common hereditary hypercoagulable disease in the United States and involves 5 of the Caucasian population. Up to 30 of patients who present with deep vein thrombosis (DVT) or pulmonary thromboembolism present with this condition. This is a case report of a 36-year-old man who experienced one episode of DVT within the previous year and was admitted to our hospital due to productive coughs and hemoptysis. Paraclinical studies demonstrated a right ventricular thrombus. Additional investigation was done to find the underlying cause. Laboratory tests were positive for Factor V Leiden mutation. Other factors for hypercoagulability states were normal. Given that Factor V Leiden mutation is a life-threatening condition with a relatively high prevalence and considering its thrombogenesis, screening tests are necessary in young patients without obvious reasons for recurrent thrombus formation. It seems that medical noninvasive treatments can be an alternative therapy to surgery when a ventricular thrombus is suspected in these patients. � 2015 Tehran Heart Center. All rights reserved

    Efficient Stark deceleration of cold polar molecules

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    Stark deceleration has been utilized for slowing and trapping several species of neutral, ground-state polar molecules generated in a supersonic beam expansion. Due to the finite physical dimension of the electrode array and practical limitations of the applicable electric fields, only molecules within a specific range of velocities and positions can be efficiently slowed and trapped. These constraints result in a restricted phase space acceptance of the decelerator in directions both transverse and parallel to the molecular beam axis; hence, careful modeling is required for understanding and achieving efficient Stark decelerator operation. We present work on slowing of the hydroxyl radical (OH) elucidating the physics controlling the evolution of the molecular phase space packets both with experimental results and model calculations. From these results we deduce experimental conditions necessary for efficient operation of a Stark decelerator.Comment: 8 pages, 9 figure

    Au nanostructured surfaces for electrochemical and localized surface plasmon resonance-based monitoring of α-synuclein-small molecule interactions.

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    In this proof-of-concept study, the fabrication of novel Au nanostructured indium tin oxide (Au-ITO) surfaces is described for the development of a dual-detection platform with electrochemical and localized surface plasmon resonance (LSPR)-based biosensing capabilities. Nanosphere lithography (NSL) was applied to fabricate Au-ITO surfaces. Oligomers of α-synuclein (αS) were covalently immobilized to determine the electrochemical and LSPR characteristics of the protein. Cyclic voltammetry (CV) and differential pulse voltammetry (DPV) were performed using the redox probe [Fe(CN)6](3-/4-) to detect the binding of Cu(II) ions and (-)-epigallocatechin-3-gallate (EGCG) to αS on the Au-ITO surface. Electrochemical and LSPR data were complemented by Thioflavin-T (ThT) fluorescence, surface plasmon resonance imaging (SPRi), and transmission electron microscopy (TEM) studies. EGCG was shown to induce the formation of amorphous aggregates that decreased the electrochemical signals. However, the binding of EGCG with αS increased the LSPR absorption band with a bathochromic shift of 10-15 nm. The binding of Cu(II) to αS enhanced the DPV peak current intensity. NSL fabricated Au-ITO surfaces provide a promising dual-detection platform to monitor the interaction of small molecules with proteins using electrochemistry and LSPR

    Spatially-dependent sensitivity of superconducting meanders as single-photon detectors

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    The photo-response of a thin current-carrying superconducting stripe with a 90-degree turn is studied within the time-dependent Ginzburg-Landau theory. We show that the photon acting near the inner corner (where the current density is maximal due to the current crowding [J. R. Clem and K. K. Berggren, Phys. Rev. B {\bf 84}, 174510 (2011)]) triggers the nucleation of superconducting vortices at currents much smaller than the expected critical one, but {\it does not} bring the system to a higher resistive state and thus remains undetected. The transition to the resistive state occurs only when the photon hits the stripe away from the corner due to there uniform current distribution across the sample, and dissipation is due to the nucleation of a kinematic vortex-antivortex pair near the photon incidence. We propose strategies to account for this problem in the measurements

    Fermion Pairing Dynamics in the Relativistic Scalar Plasma

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    Using many-body techniques we obtain the time-dependent Gaussian approximation for interacting fermion-scalar field models. This method is applied to an uniform system of relativistic spin-1/2 fermion field coupled, through a Yukawa term, to a scalar field in 3+1 dimensions, the so-called quantum scalar plasma model. The renormalization for the resulting Gaussian mean-field equations, both static and dynamical, are examined and initial conditions discussed. We also investigate solutions for the gap equation and show that the energy density has a single minimum.Comment: 21 pages, latex, 4 postscript figures, new sections, some literary changes, notation corrections, accepted for publication in Phys. Rev

    Quantum information processing using quasiclassical electromagnetic interactions between qubits and electrical resonators

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    Electrical resonators are widely used in quantum information processing, by engineering an electromagnetic interaction with qubits based on real or virtual exchange of microwave photons. This interaction relies on strong coupling between the qubits' transition dipole moments and the vacuum fluctuations of the resonator in the same manner as cavity quantum electrodynamics (QED), and has consequently come to be called 'circuit QED' (cQED). Great strides in the control of quantum information have already been made experimentally using this idea. However, the central role played by photon exchange induced by quantum fluctuations in cQED does result in some characteristic limitations. In this paper, we discuss an alternative method for coupling qubits electromagnetically via a resonator, in which no photons are exchanged, and where the resonator need not have strong quantum fluctuations. Instead, the interaction can be viewed in terms of classical, effective 'forces' exerted by the qubits on the resonator, and the resulting resonator dynamics used to produce qubit entanglement are purely classical in nature. We show how this type of interaction is similar to that encountered in the manipulation of atomic ion qubits, and we exploit this analogy to construct two-qubit entangling operations that are largely insensitive to thermal or other noise in the resonator, and to its quality factor. These operations are also extensible to larger numbers of qubits, allowing interactions to be selectively generated among any desired subset of those coupled to a single resonator. Our proposal is potentially applicable to a variety of physical qubit modalities, including superconducting and semiconducting solid-state qubits, trapped molecular ions, and possibly even electron spins in solids.United States. Dept. of Defense. Assistant Secretary of Defense for Research & Engineering (United States. Air Force Contract FA8721-05-C-0002
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