179 research outputs found

    Optical properties of femtosecond laser-treated diamond

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    A laser-induced periodic surface structure (LIPSS) has been fabricated on polycrystalline diamond by an ultrashort Ti:Sapphire pulsed laser source (λ = 800 nm, P = 3 mJ, 100 fs) in a high vacuum chamber (<10−7 mbar) in order to increase diamond absorption in the visible and infrared wavelength ranges. A horizontally polarized laser beam had been focussed perpendicularly to the diamond surface and diamond target had been moved by an automated X–Y translational stage along the two directions orthogonal to the optical axis. Scanning electron microscopy of samples reveals an LIPSS with a ripple period of about 170 nm, shorter than the laser wavelength. Raman spectra of processed sample do not point out any evident sp 2 content, and diamond peak presents a right shift, indicating a compressive stress. The investigation of optical properties of fs-laser surface textured diamond is reported. Spectral photometry in the range 200/2,000 nm wavelength shows a significant increase of visible and infrared absorption (more than 80 %) compared to untreated specimens (less than 40 %). The analysis of optical characterization data highlights a close relationship between fabricated LIPSS and absorption properties, confirming the optical effectiveness of such a treatment as a light-trapping structure for diamond: these properties, reported for the first time, open the path for new applications of CVD diamond

    Surface nanotexturing of boron-doped diamond films by ultrashort laser pulses

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    Polycrystalline boron-doped diamond (BDD) films were surface nanotextured by femtosecond pulsed laser irradiation (100 fs duration, 800 nm wavelength, 1.44 J/cm² single pulse fluence) to analyse the evolution of induced alterations on the surface morphology and structural properties. The aim was to identify the occurrence of laser-induced periodic surface structures (LIPSS) as a function of the number of pulses released on the unit area. Micro-Raman spectroscopy pointed out an increase in the graphite surface content of the films following the laser irradiation due to the formation of ordered carbon sites with respect to the pristine sample. SEM and AFM surface morphology studies allowed the determination of two different types of surface patterning: narrow but highly irregular ripples without a definite spatial periodicity or long-range order for irradiations with relatively low accumulated fluences (&lt;14.4 J/cm²) and coarse but highly regular LIPSS with a spatial periodicity of approximately 630 nm ± 30 nm for higher fluences up to 230.4 J/cm²

    The Role of Tissue Factor in Atherothrombosis and Coronary Artery Disease : Insights into Platelet Tissue Factor

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    The contribution of vessel wall-derived tissue factor (TF) to atherothrombosis is well established, whereas the pathophysiological relevance of the blood-borne TF is still a matter of debate, and controversies on the presence of platelet-associated TF still exist. In the past 15 years, several studies have documented the presence of TF in human platelets, the capacity of human platelets to use TF mRNA to make de novo protein synthesis, and the increase in the percentage of TF positive platelets in pathological conditions such as coronary artery disease (CAD). The exposure of vessel wall-derived TF at the site of vascular injury would play its main role in the initiation phase, whereas the blood-borne TF carried by platelets would be involved in the propagation phase of thrombus formation. More recent data indicate that megakaryocytes are committed to release into the bloodstream a well-defined number of TF-carrying platelets, which represents only a fraction of the whole platelet population. These findings are in line with the evidence that platelets are heterogeneous in their functions and only a subset of them is involved in the hemostatic process. In this review we summarize the existing knowledge on platelet associated TF and speculate on its relevance to physiology and to atherothrombosis and CAD

    Quality indicators for the care and outcomes of adults with atrial fibrillation

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    Aims To develop quality indicators (QIs) that may be used to evaluate the quality of care and outcomes for adults with atrial fibrillation (AF). Methods and results We followed the ESC methodology for QI development. This methodology involved (i) the identification of the domains of AF care for the diagnosis and management of AF (by a group of experts including members of the ESC Clinical Practice Guidelines Task Force for AF); (ii) the construction of candidate QIs (including a systematic review of the literature); and (iii) the selection of the final set of QIs (using a modified Delphi method). Six domains of care for the diagnosis and management of AF were identified: (i) Patient assessment (baseline and follow-up), (ii) Anticoagulation therapy, (iii) Rate control strategy, (iv) Rhythm control strategy, (v) Risk factor management, and (vi) Outcomes measures, including patient-reported outcome measures (PROMs). In total, 17 main and 17 secondary QIs, which covered all six domains of care for the diagnosis and management of AF, were selected. The outcome domain included measures on the consequences and treatment of AF, as well as PROMs. Conclusion This document defines six domains of AF care (patient assessment, anticoagulation, rate control, rhythm control, risk factor management, and outcomes), and provides 17 main and 17 secondary QIs for the diagnosis and management of AF. It is anticipated that implementation of these QIs will improve the quality of AF care

    Diabetic patients with acute coronary syndromes in contemporary European registries: characteristics and outcomes

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    In acute coronary syndromes (ACS), those with diabetes mellitus (DM) are at high risk of recurrent cardiovascular events and premature death. We described patient characteristics, ACS management, and outcomes up to 1 year after hospital admission for an ACS/index-ACS event, in patients with DM in 10 contemporary European registries. In the 10 registries there were 28,899 with and 97,505 without without DM. In the DM population, the proportion of patients with ST-Segment Elevation Myocardial Infarction (STEMI) ranged from 22.1% to 100.0% (other patients had non-ST-Segment Elevation Myocardial Infarction (NSTEMI-ACS) or unstable angina). All-cause mortality in the registries ranged from 1.4% to 9.4% in-hospital; 2.8% to 7.9% at 30 days post-discharge; 5.1% to 10.7% at 180 days post-discharge; and 3.3% to 10.5% at 1 year post-discharge. Major bleeding events were reported in up to 3.8% of patients while in hospital (8 registries); up to 1.3% at 30 days (data from two registries only), and 2.0% at 1 year (one registry only). Registries differed substantially in terms of study setting, site, patient selection, definition and schedule of endpoints, and use of various P2Y12 inhibitors. Pooled risk ratios comparing cohorts with DM vs. no DM were in-hospital significantly higher in DM for all-cause death (1.66; 95% CI 1.42-1.94), for cardiovascular death (2.33; 1.78 - 3.03), and for major bleeding (1.35; 1.21-1.52)

    Coronary stenting and surgery: Perioperative management of antiplatelet therapy in patients undergoing surgery after coronary stent implantation [Stent coronarico e chirurgia: La gestione perioperatoria della terapia antiaggregante nel paziente portatore di stent coronarico candidato a intervento chirurgico]

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    The management of antiplatelet therapy in patients with coronary stents undergoing surgery is a growing clinical problem and often represents a matter of debate between cardiologists and surgeons. It has been estimated that about 4-8% of patients undergoing coronary stenting need to undergo surgery within the next year. Surgery represents one of the most common reasons for premature antiplatelet therapy discontinuation, which is associated with a significant increase in mortality and major adverse cardiac events, in particular stent thrombosis. In addition, surgery confers an additional risk of perioperative cardiac ischemic events, being high in these patients because of the pro-inflammatory and pro-thrombotic effects of surgery. Current international guidelines recommend to postpone non-urgent surgery for at least 6 weeks after bare metal stent implantation and for 6-12 months after drug-eluting stent implantation. However, these recommendations provide little support with regard to managing antiplatelet therapy in the perioperative phase in case of urgent operations and/or high hemorrhagic risk. Furthermore, ischemic and hemorrhagic risk is not defined in detail on the basis of clinical and procedural characteristics. Finally, guidelines shared with cardiologists and surgeons are lacking. The present consensus document provides practical recommendations on the management of antiplatelet therapy in the perioperative period in patients with coronary stents undergoing surgery. Cardiologists and surgeons contributed equally to its creation. An ischemic risk stratification has been provided on the basis of clinical and procedural data. All surgical interventions have been defined on the basis of the hemorrhagic risk. A consensus on the most appropriate antiplatelet regimen in the perioperative phase has been reached on the basis of the ischemic and hemorrhagic risk. Dual antiplatelet therapy should not be withdrawn for surgery at low bleeding risk, whereas aspirin should be continued perioperatively in the majority of surgical operations. In the event of interventions at high risk for both bleeding and ischemic events, when oral antiplatelet therapy withdrawal is required, perioperative treatment with short-acting intravenous glycoprotein IIb/IIIa inhibitors (tirofiban or eptifibatide) should be considered. \ua9 2012 Il Pensiero Scientifico Editore

    2019 ESC/EAS guidelines for the management of dyslipidaemias : Lipid modification to reduce cardiovascular risk

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    Correction: Volume: 292 Pages: 160-162 DOI: 10.1016/j.atherosclerosis.2019.11.020 Published: JAN 2020Peer reviewe
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