1,195 research outputs found

    Bragg concentrators for hard (> 10 keV) X-ray astronomy: Status report

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    The use of focusing telescopes in hard X-ray (E > 10 keV) astronomy will provide better flux sensitivity and imaging perfomances with respect to the directviewing detectors, utilized until now. We present recent results obtained from our Group regarding the possible use of Bragg-diffraction technique to design hard X-ray focusing telescopes

    A greener technique for microwave-assisted O-Silylation and silyl ether deprotection of uridine and other substrates

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    A single clean, good-yielding, environment-friendly microwave-assisted procedure for O-silylation of uridine with tert-butyldimethylsilyl chloride (TBDMSCl), 1,8-Diazabicyclo(5.4.0)undec-7-ene (DBU) and potassium nitrate as catalyst under solvent-free conditions is reported. Subsequent silyl ether deprotection is accomplished with a reusable acidic resin via microwave irradiation. Both the silylation and desilylation protocols have been applied to a panel of alcohols of pharmaceutical interest

    Sweet cherry extract as permeation enhancer of tyrosine kinase inhibitors: a promising prospective for future oral anticancer therapies

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    Although patients would rather oral therapies to injections, the gastrointestinal tract's low permeability makes this method limiting for most compounds, including anticancer drugs. Due to their low bioavailability, oral antitumor therapies suffer from significant variability in pharmacokinetics and efficacy. The improvement of their pharmacokinetic profiles can be achieved by a new approach: the use of natural extracts enriched with polyphenolic compounds that act as intestinal permeability enhancers. Here, we propose a safe sweet cherry extract capable of enhancing oral absorption. The extract was characterized by the HPLC-UV/MS method, evaluated for in vitro antioxidant activity, safety on the Caco-2 cell line, and as a potential permeation enhancer. The sweet cherry extract showed a high antioxidant capacity (ABTS and DPPH assays were 211.74 and 48.65 mu mol of Trolox equivalent/g dried extract, respectively), high content of polyphenols (8.44 mg of gallic acid per gram of dry extract), and anthocyanins (1.80 mg of cyanidin-3-glucoside equivalent per g of dry extract), reassuring safety profile (cell viability never lower than 98%), and a significant and fully reversible ability to alter the integrity of the Caco-2 monolayer (+81.5% of Lucifer yellow permeability after 2 h). Furthermore, the ability of the sweet cherry extract to improve the permeability (P-app) and modify the efflux ratio (ER) of reference compounds (atenolol, propranolol, and dasatinib) and selected pyrazolo[3,4-d]pyrimidine derivatives was investigated. The obtained results show a significant increase in apparent permeability across the Caco-2 monolayer (tripled and quadrupled in most cases), and an interesting decrease in efflux ratio when compounds were co-incubated with sweet cherry extract

    A compact light readout system for longitudinally segmented shashlik calorimeters

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    The longitudinal segmentation of shashlik calorimeters is challenged by dead zones and non-uniformities introduced by the light collection and readout system. This limitation can be overcome by direct fiber-photosensor coupling, avoiding routing and bundling of the wavelength shifter fibers and embedding ultra-compact photosensors (SiPMs) in the bulk of the calorimeter. We present the first experimental test of this readout scheme performed at the CERN PS-T9 beamline in 2015 with negative particles in the 1-5~GeV energy range. In this paper, we demonstrate that the scheme does not compromise the energy resolution and linearity compared with standard light collection and readout systems. In addition, we study the performance of the calorimeter for partially contained charged hadrons to assess the e/Ď€e/\pi separation capability and the response of the photosensors to direct ionization.Comment: To appear in Nuclear Instruments and Methods in Physics Research,

    Production of the soluble pattern recognition receptor PTX3 by myeloid, but not plasmacytoid, dendritic cells

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    PTX3 is a prototypic of long pentraxin consisting of an N-terminal portion coupled to a C-terminal pentraxin domain, the latter related to short pentraxins (C-reactive protein and serum amyloid P component). PTX3 is a soluble pattern recognition receptor, which plays a non-redundant role in resistance against selected pathogens and in female fertility. The present study was designed to analyze the production of PTX3 by human dendritic cells (DC) and to define the role of different innate immunity receptors in its induction. Human monocyte-derived DC produced copious amounts of PTX3 in response to microbial ligands engaging different members of the Toll-like receptor (TLR) family (TLR1 through TLR6), whereas engagement of the mannose receptor had no substantial effect. DC were better producers of PTX3 than monocytes and macrophages. Freshly isolated peripheral blood myeloid DC produced PTX3 in response to diverse microbial stimuli. In contrast, plasmacytoid DC exposed to influenza virus or to CpG oligodeoxynucleotides engaging TLR9, did not produce PTX3. PTX3-expressing DC were present in inflammatory lymph nodes from HIV-infected patients. These results suggest that DC of myelomonocytic origin are a major source of PTX3, a molecule which facilitates pathogen recognition and subsequent activation of innate and adaptive immunity
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