4,494 research outputs found

    Millimeter-Waves Structures on Benzocyclobutene Dielectric Substrate

    Get PDF
    The need of low-loss substrate materials with stable dielectric performances is a strong requirement when working at millimeter frequencies, where standard dielectrics exhibit prohibitive losses. In this paper, the authors focus their attention on a polymer material, the benzocyclobutene (BCB), having a low dielectric constant and a low loss tangent, with a stable behavior up to THz frequencies. A specific in-house manufacture technology is described to realize millimeter-wave structures on a BCB dielectric substrate. Experimental validations on BCB-based circuits and antennas prototypes are discussed

    Radar array diagnosis from undersampled data using a compressed sensing/sparse recovery technique

    Get PDF
    A Compressed Sensing/Sparse Recovery approach is adopted in this paper for the accurate diagnosis of fault array elements from undersampled data. Experimental validations on a slotted waveguide test array are discussed to demonstrate the effectiveness of the proposed procedure in the failures retrieval from a small set of measurements with respect to the number of radiating elements. Due to the sparsity feature of the proposed formulation, the method is particularly appealing for the diagnostics of large arrays, typically adopted for radar applications

    A novel l-shaped fluorescent probe for aie sensing of zinc (Ii) ion by a dr/nir response

    Get PDF
    In the field of optical sensors, small molecules responsive to metal cations are of current interest. Probes displaying aggregation-induced emission (AIE) can solve the problems due to the aggregation-caused quenching (ACQ) molecules, scarcely emissive as aggregates in aqueous media and in tissues. The addition of a metal cation to an AIE ligand dissolved in solution can cause a “turn-on” of the fluorescence emission. Half-cruciform-shaped molecules can be a winning strategy to build specific AIE probes. Herein, we report the synthesis and characterization of a novel L-shaped fluorophore containing a benzofuran core condensed with 3-hydroxy-2-naphthaldehyde crossed with a nitrobenzene moiety. The novel AIE probe produces a fast colorimetric and fluorescence response toward zinc (II) in both in neutral and basic conditions. Acting as a tridentate ligand, it produces a complex with enhanced and red-shifted emission in the DR/NIR spectral range. The AIE nature of both compounds was examined on the basis of X-ray crystallography and DFT analysis

    Efalizumab

    Get PDF
    Introduction: Conventional systemic therapies for psoriasis are associated with serious toxicities that can limit long-term use. In recent years, biological therapies have offered the possibility of long-term therapy with improved safety and efficacy for the treatment of psoriasis. Biological therapies can be classified into three categories: the T-cell modulating agents (alefacept and efalizumab), the inhibitors of TNF-alpha (adalimumab, etanercept, infliximab) and the inhibitors of IL-12 and -23 (ustekinumab). Efalizumab is a humanized recombinant monoclonal IgG1 antibody. It targets multiple stages in the immunopathogenesis of psoriasis: initial T-cell activation, migration of T-cells into dermal and epidermal tissues, and T-cell reactivation. On 19 February 2009, the Committee for Medicinal Products for Human Use (CHMP) recommended the suspension of the marketing authorisation for efalizumab.Areas covered: Numerous clinical trials have demonstrated the efficacy, safety and health-related quality of life benefits of efalizumab in patients with moderate-to-severe chronic plaque psoriasis. Efalizumab was approved by the FDA in November 2003 and by the European Medicines Evaluation Agency in September 2004 for the treatment of adult patients with moderate-to-severe chronic plaque psoriasis. Recently, three cases of progressive multifocal leukoencephalopathy were described in patients on long-term (> 3 years) efalizumab therapy, leading to its withdrawal from the market.Expert opinion: Although initially favorable, the safety profile of efalizumab revealed the appearance of severe adverse events in long-term treated patients. Therefore, post-marketing surveillance is essential for correct evaluation of drug potential

    Benzodifuran-based fluorescent brighteners: A novel platform for plant cell wall imaging

    Get PDF
    Herein we designed three novel fluorescent brightening agents based on a benzodifuran skeleton. The compounds are colorless fluorophores emitting in the blue region with an improved water solubility and ability to interact with living cells. A complete understanding of the emission mechanisms was achieved by Density Functional Theory study based on X-ray crystallographic analysis. The fluorescence quantum yields were measured in different solvents and at different pH values. The ability of the different fluorophores to stain cell compartments of plant root samples was tested in water- and glycerol-based solutions. Through fluorescence microscopy technique two probes with a different functionalized branching chain proved to be efficient stains for plant root cell wall. The cationic probe has no harmful effect on plant tissues and is suitable for in vivo fluorescent visualization of plant root cell boundaries. This study sheds light on the potential use of brighteners containing a central benzodifuran core as tools for imaging of fixed and alive plant tissues

    Thermo-Induced Fluorochromism in Two AIE Zinc Complexes: A Deep Insight into the Structure-Property Relationship

    Get PDF
    Solid-state emitters exhibiting mechano-fluorochromic or thermo-fluorochromic responses represent the foundation of smart tools for novel technological applications. Among fluo-rochromic (FC) materials, solid-state emissive coordination complexes offer a variety of fluorescence responses related to the dynamic of noncovalent metal-ligand coordination bonds. Relevant FC behaviour can result from the targeted choice of metal cation and ligands. Herein, we report the synthesis and characterization of two different colour emitters consisting of zinc complexes obtained from N,O bidentate ligands with different electron-withdrawing substituents. The two complexes are blue and orange solid-state fluorophores, respectively, highly responsive to thermal and me-chanical stress. These emitters show a very different photoluminescent (PL) pattern as recorded before and after the annealing treatment. Through X-ray structural analysis combined with thermal analysis, infrared (IR) spectroscopy, PL, and DFT simulation we provide a comprehensive analysis of the structural feature involved in the fluorochromic response. Notably, we were able to correlate the on-off thermo-fluorochromism of the complexes with the structural rearrangement at the zinc coordination core

    Tunable Reflectarray Cell for Wide Angle Beam-Steering Radar Applications

    Get PDF
    An electronically tunable reflectarray element is proposed in this work to design beam-steering antennas useful for radar applications. A reduced size reflectarray unit cell is properly synthesized in order to extend the antenna beam scanning capabilities within a wider angular region. The radiating structure is accurately optimized to provide a full phase tuning range by adopting a single varactor load as phase shifter element. A 0.46 -reflectarray cell is designed at the frequency of 11.5 GHz, obtaining a phase agility of about 330 ∘ . The cell is successfully adopted for the design of a 21 × 21 reconfigurable reflectarray. The antenna is numerically tested for different configurations of the varactors capacitance values, and good beam-steering performances are demonstrated within a wide angular range
    corecore