269 research outputs found

    Electromagnetic wave absorption and structural properties of wide-band absorber made of graphene-printed glass-fibre composite

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    Lightweight composites combining electromagnetic wave absorption and excellent mechanical properties are required in spacecraft and aircraft. A one- dimensional metamaterial absorber consisting of a stack of glass fibre/epoxy layers and graphene nanoplatelets/epoxy films was proposed and fabricated through a facile air-spraying based printing technology and a liquid resin infusion method. The production process allows an optimum dispersion of graphene nanoplatelets, promoting adhesion and mechanical integration of the glass fibre/epoxy layers with the graphene nanoplatelets/epoxy films. According to experimental results, the proposed wide-band absorber provides a reflection coefficient lower than −10 dB in the range 8.5–16.7 GHz and an improvement of flexural modulus of more than 15%, with a total thickness of ∼1 mm. Outstanding electromagnetic wave absorption and mechanical performance make the proposed absorber more competitive in aeronautical and aerospace applications

    A comparison of audio-based deep learning methods for detecting anomalous road events

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    Road surveillance systems have an important role in monitoring roads and safeguarding their users. Many of these systems are based on video streams acquired from urban video surveillance infrastructures, from which it is possible to reconstruct the dynamics of accidents and detect other events. However, such systems may lack accuracy in adverse environmental settings: for instance, poor lighting, weather conditions, and occlusions can reduce the effectiveness of the automatic detection and consequently increase the rate of false or missed alarms. These issues can be mitigated by integrating such solutions with audio analysis modules, that can improve the ability to recognize distinctive events such as car crashes. For this purpose, in this work we propose a preliminary analysis of solutions based on Deep Learning techniques for the automatic identification of hazardous events through the analysis of audio spectrograms

    Artificial Intelligence Applications in Cardiovascular Magnetic Resonance Imaging: Are We on the Path to Avoiding the Administration of Contrast Media?

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    In recent years, cardiovascular imaging examinations have experienced exponential growth due to technological innovation, and this trend is consistent with the most recent chest pain guidelines. Contrast media have a crucial role in cardiovascular magnetic resonance (CMR) imaging, allowing for more precise characterization of different cardiovascular diseases. However, contrast media have contraindications and side effects that limit their clinical application in determinant patients. The application of artificial intelligence (AI)-based techniques to CMR imaging has led to the development of non-contrast models. These AI models utilize non-contrast imaging data, either independently or in combination with clinical and demographic data, as input to generate diagnostic or prognostic algorithms. In this review, we provide an overview of the main concepts pertaining to AI, review the existing literature on non-contrast AI models in CMR, and finally, discuss the strengths and limitations of these AI models and their possible future development

    Molecular mechanisms of photosensitization induced by drugs XIV: Two different behaviours in the photochemistry and photosensitization of antibacterials containing a fluoroquinolone like chromophore

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    This paper deals with the photosensitizing activity of FLQs towards two different biosubstrates, membrane and DNA. Thein vitrophototoxic activity of these drugsvs.DNA presents peculiar features with respect to thatvs.membranes, probably due to a specific binding of the drugs to the double helix and to the operativeness of different photosensitization mechanisms with the two types of biosubstrates. A description of the UVA photochemistry and the photosensitizing properties of two significant examples in the FLQ family is reported. The investigated compounds are Enoxacin, 1-ethyl-6-fluoro-1,4-dihydro-4- oxo-7-[1-piperazinyl]-1,8-naphtyridine-3-carboxilic acid and Rufloxacin, 9-fluoro-2,3-dihydro-10-4´-methyl- 1´-piperazinyl-7-oxo-7H-pyrido[1,2,3−de]-1,4-benzothiazine-6-carboxylic acid

    Fast path and polarisation manipulation of telecom wavelength single photons in lithium niobate waveguide devices

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    We demonstrate fast polarisation and path control of photons at 1550 nm in lithium niobate waveguide devices using the electro-optic effect. We show heralded single photon state engineering, quantum interference, fast state preparation of two entangled photons and feedback control of quantum interference. These results point the way to a single platform that will enable the integration of nonlinear single photon sources and fast reconfigurable circuits for future photonic quantum information science and technology.Comment: 6 page

    Gallium Arsenide (GaAs) Quantum Photonic Waveguide Circuits

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    Integrated quantum photonics is a promising approach for future practical and large-scale quantum information processing technologies, with the prospect of on-chip generation, manipulation and measurement of complex quantum states of light. The gallium arsenide (GaAs) material system is a promising technology platform, and has already successfully demonstrated key components including waveguide integrated single-photon sources and integrated single-photon detectors. However, quantum circuits capable of manipulating quantum states of light have so far not been investigated in this material system. Here, we report GaAs photonic circuits for the manipulation of single-photon and two-photon states. Two-photon quantum interference with a visibility of 94.9 +/- 1.3% was observed in GaAs directional couplers. Classical and quantum interference fringes with visibilities of 98.6 +/- 1.3% and 84.4 +/- 1.5% respectively were demonstrated in Mach-Zehnder interferometers exploiting the electro-optic Pockels effect. This work paves the way for a fully integrated quantum technology platform based on the GaAs material system.Comment: 10 pages, 4 figure

    MBSE Certification-Driven Design of a UAV MALE Configuration in the AGILE 4.0 Design Environment

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    This paper presents a certification-driven design process for an Unmanned Medium-Altitude- Long-Endurance (UAV MALE) air vehicle, including on-board system design and placements, electro-magnetic compatibility analysis, and thermal risk assessments. In literature, the preliminary aircraft design phase is mainly driven by mission performances and structural integrity aspects. However, the inclusion of other disciplines, like on-board system design or electro-magnetic compatibility, or thermal analysis, can lead to more efficient and cost- effective solutions and becomes paramount for non-conventional configurations like unmanned vehicles or highly electrified platforms. In the EC-funded AGILE 4.0 project (2019-2022), the traditional scope of the preliminary aircraft design is extended by including domains that are usually considered only in later design phases, such as certification, production and maintenance. In this paper, the AGILE 4.0 design environment supports the definition and execution of a certification-driven design process of a UAV MALE configuration, using a Model-Based Systems Engineering (MBSE) approach

    Failure to establish HIV care: characterizing the no show phenomenon

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    It is estimated that up to one-third of persons with known human immunodeficiency virus (HIV) infection in the United States are not engaged in care. We evaluated factors associated with patients\u27 failure to establish outpatient HIV care at our clinic and found that females, racial minorities, and patients lacking private health insurance were more likely to be no shows. At the clinic level, longer waiting time from the call to schedule a new patient visit to the appointment date was associated with failure to establish care. Because increased numbers of patients will be in need of outpatient HIV care as a result of recent Centers for Disease Control and Prevention guidelines advocating routine HIV testing, it is imperative that strategies to improve access are developed to overcome the no show phenomenon

    Lack of validity of self-reported mammography data

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    This qualitative literature review aimed to describe the totality of peer-reviewed scientific evidence from 1990 to 2017 concerning validity of self-reported mammography. This review included articles about mammography containing the words accuracy, validity, specificity, sensitivity, reliability or reproducibility; titles containing self-report, recall or patient reports, and breast or ‘mammo’; and references of identified citations focusing on evaluation of 2-year self-reports. Of 45 publications meeting the eligibility criteria, 2 conducted in 1993 and 1995 at health maintenance organisations in Western USA which primarily served highly educated whites provided support for self-reports of mammography over 2 years. Methodological concerns about validity of self-reports included (1) telescoping, (2) biased overestimates particularly among black women, (3) failure to distinguish screening and diagnostic mammography, and (4) failure to address episodic versus consistent mammography use. The current totality of evidence supports the need for research to reconsider the validity of self-reported mammography data as well as the feasibility of alternative surveillance data sources to achieve the goals of the Healthy People Initiative
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