3,498 research outputs found

    Antiphosphatidylserine antibody as a cause of multiple dural venous sinus thromboses and ST-elevation myocardial infarction

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    Objective: Rare disease Background: Antiphospholipid syndrome (APS) is an autoimmune disease characterized by antibodies directed against phos-pholipids on plasma membranes. Through unclear mechanisms, APS confers hypercoagulability. APS may cause recurrent thromboses in the arterial and venous vasculature. We report a case of primary APS resulting in cerebral venous thrombosis and ST-elevation myocardial infarction (STEMI) for which only antiphosphatidylserine (aPS) IgM antibody was positive after extensive investigation. Case Report: A 48-year-old male was admitted after a witnessed generalized seizure with subsequent confusion. Imaging demonstrated thrombosis of multiple central nervous system (CNS) sinuses, including the superior sagittal sinus and bilateral transverse sinuses. The patient was heparinized with aggressive hydration, which proved inadequate, prompting endovascular thrombectomy. Three months later, despite anticoagulation therapy, the patient developed a STEMI when International Normalized Ratio (INR) was 1.8. Echocardiogram (ECHO) and PAN CT scan were normal. Initial coagulation studies demonstrated normal anticardiolipin antibody, prothrombin time, partial thromboplastin time, and platelet count. Outpatient coagulation studies revealed normal an-tithrombin III, protein C/S, hemoglobin electrophoresis, homocysteine, anti-b2 glycoprotein 1 antibodies, and D-Dimer. Factor V Leiden, JAK 2 mutation, prothrombin gene mutation, and tests for paroxysmal nocturnal he-moglobinuria (PNH) were negative. A positive phosphatidylserine IgM was detected. The patient was continued on warfarin (10 mg daily) with a target INR of 3.0–3.5 and clopidogrel (75 mg daily). Conclusions: Despite extensive investigation, this patient only showed evidence of elevated aPS IgM antibodies, likely contributing to his CNS venous sinus thromboses and STEMI. It is important to screen for antiphosphatidylserine antibodies in cases of unprovoked thrombosis when standard thrombophilia analysis is unrevealing. This will assist in identifying pathogenicity and help prevent recurrence of subsequent thromboses. Β© Am J Case Rep, 2018

    The taxonomy of Cyclospora.

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    Entanglement of mechanical oscillators coupled to a non-equilibrium environment

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    Recent experiments aim at cooling nanomechanical resonators to the ground state by coupling them to non-equilibrium environments in order to observe quantum effects such as entanglement. This raises the general question of how such environments affect entanglement. Here we show that there is an optimal dissipation strength for which the entanglement between two coupled oscillators is maximized. Our results are established with the help of a general framework of exact quantum Langevin equations valid for arbitrary bath spectra, in and out of equilibrium. We point out why the commonly employed Lindblad approach fails to give even a qualitatively correct picture

    Brillouin Cooling

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    We analyze how to exploit Brillouin scattering for the purpose of cooling opto-mechanical devices and present a quantum-mechanical theory for Brillouin cooling. Our analysis shows that significant cooling ratios can be obtained with standard experimental parameters. A further improvement of cooling efficiency is possible by increasing the dissipation of the optical anti-Stokes resonance.Comment: 4 pages 3 figure

    Free-space quantum links under diverse weather conditions

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    Free-space optical communication links are promising channels for establishing secure quantum communication. Here we study the transmission of nonclassical light through a turbulent atmospheric link under diverse weather conditions, including rain or haze. To include these effects, the theory of light transmission through atmospheric links in the elliptic-beam approximation presented by Vasylyev et al. [D. Vasylyev et al., Phys. Rev. Lett. 117, 090501 (2016); arXiv:1604.01373] is further generalized.It is demonstrated, with good agreement between theory and experiment, that low-intensity rain merely contributes additional deterministic losses, whereas haze also introduces additional beam deformations of the transmitted light. Based on these results, we study theoretically the transmission of quadrature squeezing and Gaussian entanglement under these weather conditions.Comment: 14 pages, 8 figure

    Π£Ρ‡Π΅Π½ΠΎΠΌΡƒ ΡΠ΅ΠΊΡ€Π΅Ρ‚Π°Ρ€ΡŽ Π Π΅Π΄ΠΊΠΎΠ»Π»Π΅Π³ΠΈΠΈ ΠΆΡƒΡ€Π½Π°Π»Π° "Π˜Π·Π²Π΅ΡΡ‚ΠΈΡ ВПУ" Π΄ΠΎΡ†Π΅Π½Ρ‚Ρƒ Π‘. Π‘. ΠœΠΎΠ³ΠΈΠ»ΡŒΠ½ΠΈΡ†ΠΊΠΎΠΌΡƒ - 60 Π»Π΅Ρ‚

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    Описан ΠΆΠΈΠ·Π½Π΅Π½Π½Ρ‹ΠΉ ΠΏΡƒΡ‚ΡŒ, Π»ΠΈΡ‡Π½Ρ‹Π΅ качСства, учСбная ΠΈ научная Π΄Π΅ΡΡ‚Π΅Π»ΡŒΠ½ΠΎΡΡ‚ΡŒ ΠΈ достиТСния ΡƒΡ‡Π΅Π½ΠΎΠ³ΠΎ сСкрСтаря Π Π΅Π΄ΠΊΠΎΠ»Π»Π΅Π³ΠΈΠΈ ΠΆΡƒΡ€Π½Π°Π»Π° "Π˜Π·Π²Π΅ΡΡ‚ΠΈΡ ВПУ", ΠΊΠ°Π½Π΄ΠΈΠ΄Π°Ρ‚Π° Ρ„ΠΈΠ·ΠΈΠΊΠΎ-матСматичСских Π½Π°ΡƒΠΊ, Π΄ΠΎΡ†Π΅Π½Ρ‚Π° Вомского политСхничСского унивСрситСта БСргСя Борисовича ΠœΠΎΠ³ΠΈΠ»ΡŒΠ½ΠΈΡ†ΠΊΠΎΠ³

    Theory of ground state cooling of a mechanical oscillator using dynamical back-action

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    A quantum theory of cooling of a mechanical oscillator by radiation pressure-induced dynamical back-action is developed, which is analogous to sideband cooling of trapped ions. We find that final occupancies well below unity can be attained when the mechanical oscillation frequency is larger than the cavity linewidth. It is shown that the final average occupancy can be retrieved directly from the optical output spectrum.Comment: 5 pages, 2 figure

    Free-space propagation of high dimensional structured optical fields in an urban environment

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    Spatially structured optical fields have been used to enhance the functionality of a wide variety of systems that use light for sensing or information transfer. As higher-dimensional modes become a solution of choice in optical systems, it is important to develop channel models that suitably predict the effect of atmospheric turbulence on these modes. We investigate the propagation of a set of orthogonal spatial modes across a free-space channel between two buildings separated by 1.6 km. Given the circular geometry of a common optical lens, the orthogonal mode set we choose to implement is that described by the Laguerre-Gaussian (LG) field equations. Our study focuses on the preservation of phase purity, which is vital for spatial multiplexing and any system requiring full quantumstate tomography. We present experimental data for the modal degradation in a real urban environment and draw a comparison to recognized theoretical predictions of the link. Our findings indicate that adaptations to channel models are required to simulate the effects of atmospheric turbulence placed on high-dimensional structured modes that propagate over a long distance. Our study indicates that with mitigation of vortex splitting, potentially through precorrection techniques, one could overcome the challenges in a real point-to-point free-space channel in an urban environment
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