165 research outputs found

    Proposed cavity Josephson plasmonics with complex-oxide heterostructures

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    We discuss how complex-oxide heterostructures that include high-Tc superconducting cuprates can be used to realize an array of sub-millimeter cavities that support Josephson plasmon polaritons. These cavities have several attractive features for new types of light matter interaction studies and we show that they promote "ultrastrong" coupling between THz frequency radiation and Josephson plasmons. Cavity electrodynamics of Josephson plasmons allows to manipulate the superconducting order-parameter phase coherence. As an example, we discuss how it could be used to cool superconducting phase fluctuations with light

    Upper limits to surface force disturbances on LISA proof masses and the possibility of observing galactic binaries

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    We report on the measurement of parasitic surface force noise on a hollow replica of a LISA (Laser Interferometer Space Antenna for the observation of gravitational waves) proof mass surrounded by a faithful representation of its in flight surroundings, namely the capacitive sensor used to detect proof-mass motion. Parasitic forces are detected through the corresponding torque exerted on the proof mass and measured with a torsion pendulum in the frequency range 0.1 30 mHz. The sensor electrodes, electrode housing and associated readout electronics have the same nominal design as for the flight hardware, including 4 mm gaps around the proof mass along the sensitive laser interferometry axis. We show that the measured upper limit for surface forces would allow detection of a number of galactic binaries signals with signal to noise ratio up to approximately 40 for 1 year integration. We also discuss how the flight test under development, LISA Pathfinder, will substantially improve this limit, approaching the performance required for LISA.Comment: 3 Figures. Submitted to Physical Review Letter

    An unusual pathological finding of chronic lymphocitic leukemia and adenocarcinoma of the prostate after transurethral resection for complete urinary retention: case report

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    BACKGROUND: We describe a patient who underwent transurethral resection of the prostate for urinary obstructive symptoms and had histological findings of adenocarcinoma of the prostate with prostatic localization of chronic lymphocitic leukemia (CLL).The contemporary presence of CLL, adenocarcinoma of the prostate and residual prostatic gland after transurethral resection has never been reported before and the authors illustrate how they managed this unusual patient. CASE PRESENTATION: A 79-years-old white man, presented with acute urinary retention, had a peripheral blood count with an elevated lymphocytosis (21.250/mL) with a differential of 65.3% lymphocytes and the prostate-specific antigen (PSA) value was 3.38 ng/mL with a percent free PSA of 8.28%. The transrectal ultrasound (TRUS) indicated an isoechonic and homogenic enlarged prostate of 42 cm(3 )and the abdomen ultrasound found a modest splenomegaly and no peripheral lymphadenophaty. The patient underwent transurethral resection of the prostate and had a pathological finding of adenocarcinoma in the prostate with a Gleason Score 4 (2+2) of less than 5% of the material (clinical stage T1a), associated with a diffused infiltration of chronic lymphocitic leukemia elements. CONCLUSIONS: The incidental finding of a prostatic localization of a low-grade non-Hodgkin's lymphoma does not modify eventually further treatments for neither prostate cancer nor lymphoma. The presence of a low-grade and low-stage lymphoma, confirmed by a hematological evaluation, and the simultaneous evidence of an adenocarcinoma after transurethral resection of the prostate for acute urinary retention do not require any immediate treatment due to its long-term survival rate and the follow-up remains based on periodical PSA evaluation and complete blood count

    Heparin Strongly Enhances the Formation of β2-Microglobulin Amyloid Fibrils in the Presence of Type I Collagen

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    The tissue specificity of fibrillar deposition in dialysis-related amyloidosis is most likely associated with the peculiar interaction of beta2-microglobulin (beta2-m) with collagen fibers. However, other co-factors such as glycosaminoglycans might facilitate amyloid formation. In this study we have investigated the role of heparin in the process of collagen-driven amyloidogenesis. In fact, heparin is a well known positive effector of fibrillogenesis, and the elucidation of its potential effect in this type of amyloidosis is particularly relevant because heparin is regularly given to patients subject to hemodialysis to prevent blood clotting. We have monitored by atomic force microscopy the formation of beta2-m amyloid fibrils in the presence of collagen fibers, and we have discovered that heparin strongly accelerates amyloid deposition. The mechanism of this effect is still largely unexplained. Using dynamic light scattering, we have found that heparin promotes beta2-m aggregation in solution at pH 6.4. Morphology and structure of fibrils obtained in the presence of collagen and heparin are highly similar to those of natural fibrils. The fibril surface topology, investigated by limited proteolysis, suggests that the general assembly of amyloid fibrils grown under these conditions and in vitro at low pH is similar. The exposure of these fibrils to trypsin generates a cleavage at the C-terminal of lysine 6 and creates the 7-99 truncated form of beta2-m (DeltaN6beta2-m) that is a ubiquitous constituent of the natural beta2-m fibrils. The formation of this beta2-m species, which has a strong propensity to aggregate, might play an important role in the acceleration of local amyloid deposition

    Ultrafast insulator-to-metal phase transition as a switch to measure the spectrogram of a supercontinuum light pulse

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    In this letter we demonstrate the possibility to determine the temporal and spectral structure (spectrogram) of a complex light pulse exploiting the ultrafast switching character of a nonthermal photoinduced phase transition. As a proof, we use a VO2 multifilm, undergoing an ultrafast insulator-to-metal phase transition when excited by femtosecond near-infrared laser pulses. The abrupt variation in the multifilm optical properties, over a broad infrared/visible frequency range, is exploited to determine, in situ and in a simple way, the spectrogram of a supercontinuum pulse produced by a photonic crystal fiber. The determination of the structure of the pulse is mandatory to develop pump-probe experiments with frequency resolution over a broad spectral range (700-1100 nm)

    Freezing of Gait in Parkinson's Disease Patients Treated with Bilateral Subthalamic Nucleus Deep Brain Stimulation: A Long-Term Overview

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    Bilateral subthalamic nucleus deep brain stimulation (STN-DBS) is an effective treatment in advanced Parkinson's Disease (PD). However, the effects of STN-DBS on freezing of gait (FOG) are still debated, particularly in the long-term follow-up (≥5-years). The main aim of the current study is to evaluate the long-term effects of STN-DBS on FOG. Twenty STN-DBS treated PD patients were included. Each patient was assessed before surgery through a detailed neurological evaluation, including FOG score, and revaluated in the long-term (median follow-up: 5-years) in different stimulation and drug conditions. In the long term follow-up, FOG score significantly worsened in the off-stimulation/off-medication condition compared with the pre-operative off-medication assessment (z = -1.930; p = 0.05) but not in the on-stimulation/off-medication (z = -0.357; p = 0.721). There was also a significant improvement of FOG at long-term assessment by comparing on-stimulation/off-medication and off-stimulation/off-medication conditions (z = -2.944; p = 0.003). These results highlight the possible beneficial long-term effects of STN-DBS on FOG
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