2,671 research outputs found

    Trombose tripla, simultânea, muito tardia de stents coronários

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    Abstract Coronary artery stent thrombosis is an uncommon but potentially catastrophic complication. The risk of very late stent thrombosis (VLST) raises important safety issues regarding the first generation of drug-eluting stents (DES). Although several complex mechanisms for VLST have been suggested and various predictors have been described, its pathophysiology is not completely understood and it is not known whether longer-term dual antiplatelet therapy reduces the risk. We present a rare case of simultaneous very late DES thrombosis in the three vascular territories, following discontinuation of antiplatelet therapy seven years after stent placement, presenting as cardiogenic shock

    Mechanical properties and formation mechanisms of a wire of single gold atoms

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    A scanning tunneling microscope (STM) supplemented with a force sensor is used to study the mechanical properties of a novel metallic nanostructure: a freely suspended chain of single gold atoms. We find that the bond strength of the nanowire is about twice that of a bulk metallic bond. We perform ab initio calculations of the force at chain fracture and compare quantitatively with experimental measurements. The observed mechanical failure and nanoelastic processes involved during atomic wire fabrication are investigated using molecular dynamics (MD) simulations, and we find that the total effective stiffness of the nanostructure is strongly affected by the detailed local atomic arrangement at the chain bases.Comment: To be published in Phys. Rev. Lett. 4 pages with 3 figure

    A New Linear Logic for Deadlock-Free Session-Typed Processes

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    The π -calculus, viewed as a core concurrent programming language, has been used as the target of much research on type systems for concurrency. In this paper we propose a new type system for deadlock-free session-typed π -calculus processes, by integrating two separate lines of work. The first is the propositions-as-types approach by Caires and Pfenning, which provides a linear logic foundation for session types and guarantees deadlock-freedom by forbidding cyclic process connections. The second is Kobayashi’s approach in which types are annotated with priorities so that the type system can check whether or not processes contain genuine cyclic dependencies between communication operations. We combine these two techniques for the first time, and define a new and more expressive variant of classical linear logic with a proof assignment that gives a session type system with Kobayashi-style priorities. This can be seen in three ways: (i) as a new linear logic in which cyclic structures can be derived and a CYCLE -elimination theorem generalises CUT -elimination; (ii) as a logically-based session type system, which is more expressive than Caires and Pfenning’s; (iii) as a logical foundation for Kobayashi’s system, bringing it into the sphere of the propositions-as-types paradigm

    Tuberculosis Infection in HIV Vs Non‐HIV Patients

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    Objectives: Tuberculosis (TB) is the most common opportunistic infection and cause of mortality among people living with HIV, and it is possible that it may also influence the evolution of the HIV infection. We assessed the differences between HIV-positive and -negative people infected with TB. Methods: The present study is a cross-sectional retrospective study by electronic record revision. We included patients admitted to a tertiary hospital with a diagnosis of TB between 2011 and 2016, comparing those with HIV coinfection with non-HIV patients, according to demographic and clinical characteristics. Results: This study included 591 patients, of whom 32% were HIV-coinfected. HIV-TB patients were younger, with a predominance of male gender. Considering TB risk factors, there was a higher prevalence of homelessness and intravenous drug use in the HIV group. In the non-HIV group, direct contact with other patients with TB and immunosuppression were more prevalent. Relative to TB characteristics, the HIV-coinfected group presents with a higher prevalence of disseminated disease and a higher occurrence of previous TB infection. Cancer was the most frequent cause of immunosuppression in the HIV group and the number testing positive for TB via microbiological culture was lower. Assessment of microbiological resistance and in-hospital mortality showed similar numbers in both groups. Conclusions: There are few papers comparing clinical course of TB between HIV-infected and non-infected patients. Our study differs from others in the literature as we focused on a country with middling incidence of TB and further characterized the differences between HIV-infected and non-infected patients which can contribute to the management of these patients.info:eu-repo/semantics/publishedVersio

    Calibration of the length of a chain of single gold atoms

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    Using a scanning tunneling microscope or mechanically controllable break junctions it has been shown that it is possible to control the formation of a wire made of single gold atoms. In these experiments an interatomic distance between atoms in the chain of ~3.6 Angstrom was reported which is not consistent with recent theoretical calculations. Here, using precise calibration procedures for both techniques, we measure length of the atomic chains. Based on the distance between the peaks observed in the chain length histogram we find the mean value of the inter-atomic distance before chain rupture to be 2.6 +/- 0.2 A . This value agrees with the theoretical calculations for the bond length. The discrepancy with the previous experimental measurements was due to the presence of He gas, that was used to promote the thermal contact, and which affects the value of the work function that is commonly used to calibrate distances in scanning tunnelling microscopy and mechanically controllable break junctions at low temperatures.Comment: 6 pages, 6 figure
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