7,322 research outputs found

    Vagus nerve stimulation: A new approach to reduce heart failure

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    Autonomic imbalance with increased adrenergic and reduced parasympathetic activity is involved in the development and progress of heart failure (HF). Experimental data have demonstrated that stimulation of the vagus nerve is able to reverse ventricular remodeling of the failing heart. There is also evidence that increasing parasympathetic activity may stimulate the production of nitric oxide, and reduce the devastating inflammatory process involved in HF. Vagus nerve stimulation (VNS) has been successfully applied for many years to treat drug resistant epilepsy. The first study of right vagus stimulation in patients with advance HF has proven the feasibility and safety of this new approach. Long term follow-up of increased vagal tone over 12 months with a specially designed stimulating system (CardioFit, BioControl, Yehud, Israel) has demonstrated that symptoms of HF can be significantly diminished, left ventricular ejection fraction increased, and ventricular volumes reduced. These recently published data are very promising and may offer another approach for patients with advanced HF already treated with optimal medical therapy. A prospective randomized trial with a larger patient cohort is needed to confirm these beneficial results of VNS. (Cardiol J 2010; 17, 6: 638-643

    Mapping and Monitoring Urban Environment through Sentinel-1 SAR Data: A Case Study in the Veneto Region (Italy)

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    Focusing on a sustainable and strategic urban development, local governments and public administrations, such as the Veneto Region in Italy, are increasingly addressing their urban and territorial planning to meet national and European policies, along with the principles and goals of the 2030 Agenda for the Sustainable Development. In this regard, we aim at testing a methodology based on a semi-automatic approach able to extract the spatial extent of urban areas, referred to as \u201curban footprint\u201d, from satellite data. In particular, we exploited Sentinel-1 radar imagery through multitemporal analysis of interferometric coherence as well as supervised and non-supervised classi\ufb01cation algorithms. Lastly, we compared the results with the land cover map of the Veneto Region for accuracy assessments. Once properly processed and classi\ufb01ed, the radar images resulted in high accuracy values, with an overall accuracy ranging between 85% and 90% and percentages of urban footprint di\ufb00ering by less than 1%\u20132% with respect to the values extracted from the reference land cover map. These results provide not only a reliable and useful support for strategic urban planning and monitoring, but also potentially identify a solid organizational data\ufb02ow process to prepare geographic indicators that will help answering the needs of the 2030 Agenda (in particular the goal 11 \u201cSustainable Cities and Communities\u201d)

    Does the inflow velocity profile influence physiologically relevant flow patterns in computational hemodynamic models of left anterior descending coronary artery?

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    Patient-specific computational fluid dynamics is a powerful tool for investigating the hemodynamic risk in coronary arteries. Proper setting of flow boundary conditions in computational hemodynamic models of coronary arteries is one of the sources of uncertainty weakening the findings of in silico experiments, in consequence of the challenging task of obtaining in vivo 3D flow measurements within the clinical framework. Accordingly, in this study we evaluated the influence of assumptions on inflow velocity profile shape on coronary artery hemodynamics. To do that, (1) ten left anterior descending coronary artery (LAD) geometries were reconstructed from clinical angiography, and (2) eleven velocity profiles with realistic 3D features such as eccentricity and differently shaped (single- and double-vortex) secondary flows were generated analytically and imposed as inflow boundary conditions. Wall shear stress and helicity-based descriptors obtained prescribing the commonly used parabolic velocity profile were compared with those obtained with the other velocity profiles. Our findings indicated that the imposition of idealized velocity profiles as inflow boundary condition is acceptable as long the results of the proximal vessel segment are not considered, in LAD coronary arteries. As a pragmatic rule of thumb, a conservative estimation of the length of influence of the shape of the inflow velocity profile on LAD local hemodynamics can be given by the theoretical entrance length for cylindrical conduits in laminar flow conditions

    Author Correction: Optoelectronic mixing with high-frequency graphene transistors.

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    Graphene is ideally suited for optoelectronics. It offers absorption at telecom wavelengths, high-frequency operation and CMOS-compatibility. We show how high speed optoelectronic mixing can be achieved with high frequency (~20 GHz bandwidth) graphene field effect transistors (GFETs)

    IART® (Intra-Operative Avidination for Radionuclide Therapy) for accelerated radiotherapy in breast cancer patients. Technical aspects and preliminary results of a phase II study with 90Y-labelled biotin

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    Background: Breast conserving surgery (BCS) plus external beam radiotherapy (EBRT) is considered the standard treatment for early breast cancer. We have investigated the possibility of irradiating the residual gland, using an innovative nuclear medicine approach named IART® (Intra-operative Avidination for Radionuclide Therapy). Aim: The objective of this study was to determine the optimal dose of avidin with a fixed activity (3.7 GBq) of 90Y-biotin, in order to provide a boost of 20 Gy, followed by EBRT to the whole breast (WB) at the reduced dose of 40 Gy. Local and systemic toxicity, patient's quality of life, including the cosmetic results after the combined treatment with IART® and EBRT, were assessed. Methods: After tumour excision, the surgeon injected native avidin diluted in 30 ml of saline solution into and around the tumour bed (see video). Patients received one of three avidin dose levels: 50 mg (10 pts), 100 mg (15 pts) and 150 mg (10 pts). Between 12 to 24 h after surgery, 3.7 GBq 90Y-biotin spiked with 185 MBq 111In-biotin was administered intravenously (i.v.). Whole body scans and SPECT images were performed up to 30 h post-injection for dosimetric purposes. WB-EBRT was administered four weeks after the IART® boost. Local toxicity and quality of life were evaluated. Results: Thirty-five patients were evaluated. No side effects were observed after avidin administration and 90Y-biotin infusion. An avidin dose level of 100 mg resulted the most appropriate in order to deliver the required radiation dose (19.5 + 4.0 Gy) to the surgical bed. At the end of IART®, no local toxicity occurred and the overall cosmetic result was good. The tolerance to the reduced EBRT was also good. The highest grade of transient local toxicity was G3, which occurred in 3/32 pts following the completion of WB-EBRT. The combination of IART® +EBRT was well accepted by the patients, without any changes to their quality of life. Conclusions: These preliminary results support the hypothesis that IART® may represent a valid approach to accelerated WB irradiation after BCS. We hope that this nuclear medicine technique will contribute to a better management of breast cancer patients. © the authors; licensee ecancermedicalscience

    Improving lipid management in patients with acute coronary syndrome : The ACS Lipid EuroPath tool

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    Post-acute coronary syndrome (ACS) patients are at very high risk for recurrent events and mortality, despite the availability of effective pharmacological approaches. In 2018, the ACS EuroPath Survey, performed in collaboration with 555 European cardiologists, identified a sub-optimal LDL-C management in post-ACS patients. Based on these premises, the ACS EuroPath II project led to the development of a self-assessment tool to improve lipid management in these very high risk patients, taking into consideration the new 2019 ESC/EAS guidelines. This tool is built in 3 sections. The first is a questionnaire to assess the lipid management practice from the acute phase up to 12 months of follow-up. The main topics covered in this section relate to 1) acute phase (lipid management of ACS patients during hospitalization; 2) discharge (lipid management at discharge, with focus on follow-up plan); 3) follow-up (lipid management at the time of first and subsequent follow-ups); 4) referral pathway for definitive lipid management care of post-ACS patients; 5) evaluation of the achieved goal at 6 months to 1 year and key implications. The second section is a brief report to position the results against other European Union clinical practice and European guidelines. The last section allows the physician to evaluate and consider the implementation of one or more strategies, successfully developed in leading European centers, in order to optimize their own clinical practice

    Graphene-based mid-infrared room-temperature pyroelectric bolometers with ultrahigh temperature coefficient of resistance.

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    There is a growing number of applications demanding highly sensitive photodetectors in the mid-infrared. Thermal photodetectors, such as bolometers, have emerged as the technology of choice, because they do not need cooling. The performance of a bolometer is linked to its temperature coefficient of resistance (TCR, ∼2-4% K-1 for state-of-the-art materials). Graphene is ideally suited for optoelectronic applications, with a variety of reported photodetectors ranging from visible to THz frequencies. For the mid-infrared, graphene-based detectors with TCRs ∼4-11% K-1 have been demonstrated. Here we present an uncooled, mid-infrared photodetector, where the pyroelectric response of a LiNbO3 crystal is transduced with high gain (up to 200) into resistivity modulation for graphene. This is achieved by fabricating a floating metallic structure that concentrates the pyroelectric charge on the top-gate capacitor of the graphene channel, leading to TCRs up to 900% K-1, and the ability to resolve temperature variations down to 15 μK

    Optoelectronic mixing with high-frequency graphene transistors

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    Graphene is ideally suited for optoelectronics. It offers absorption at telecom wavelengths, high-frequency operation and CMOS-compatibility. We show how high speed optoelectronic mixing can be achieved with high frequency (~20 GHz bandwidth) graphene field effect transistors (GFETs). These devices mix an electrical signal injected into the GFET gate and a modulated optical signal onto a single layer graphene(SLG) channel. The photodetection mechanism and the resulting photocurrent sign depend on theSLG Fermi level (EF). At low EF (<130 meV), a positive photocurrent is generated, while at large EF (>130 meV), a negative photobolometric current appears. This allows our devices to operate up to at least 67 GHz. Our results pave the way for GFETs optoelectronic mixers for mm-wave applications, such as telecommunications andradio/light detection and ranging(RADAR/LIDARs.)

    Graphene-based mid-infrared room-temperature pyroelectric bolometers with ultrahigh temperature coefficient of resistance

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    There is a growing number of applications demanding highly sensitive photodetectors in the mid-infrared. Thermal photodetectors, such as bolometers, have emerged as the technology of choice, because they do not need cooling. The performance of a bolometer is linked to its temperature coefficient of resistance (TCR 2–4%K^(-1) for state-of-the-art materials). Graphene is ideally suited for optoelectronic applications, with a variety of reported photodetectors ranging from visible to THz frequencies. For the mid-infrared, graphene-based detectors with TCRs 4–11%K^(-1) have been demonstrated. Here we present an uncooled, mid-infrared photodetector, where the pyroelectric response of a LiNbO3 crystal is transduced with high gain (up to 200) into resistivity modulation for graphene. This is achieved by fabricating a floating metallic structure that concentrates the pyroelectric charge on the top-gate capacitor of the graphene channel, leading to TCRs up to 900%K^(-1), and the ability to resolve temperature variations down to 15mK
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