435 research outputs found

    Carbon supported bimetallic Ru‐Co catalysts for H2 production through NaBH4 and NH3BH3 hydrolysis

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    Summary This work investigates the effect of the addition of small amounts of Ru (0.5-1 wt%) to carbon supported Co (10 wt%) catalysts towards both NaBH4 and NH3BH3 hydrolysis for H2 production. In the sodium borohydride hydrolysis, the activity of Ru-Co/carbon catalysts was sensibly higher than the sum of the activities of corresponding monometallic samples, whereas for the ammonia borane hydrolysis, the positive effect of Ru-Co systems with regard to catalytic activity was less evident. The performances of Ru-Co bimetallic catalysts correlated with the occurrence of an interaction between Ru and Co species resulting in the formation of smaller ruthenium and cobalt oxide particles with a more homogeneous dispersion on the carbon support. It was proposed that Ru°, formed during the reduction step of the Ru-Co catalysts, favors the H2 activation, thus enhancing the reduction degree of the cobalt precursor and the number of Co nucleation centers. A subsequent reduction of cobalt and ruthenium species also occurs in the hydride reaction medium, and therefore the state of the catalyst before the catalytic experiment determines the state of the active phase formed in situ. The different relative reactivity of the Ru and Co active species towards the two investigated reactions accounted for the different behavior towards NaBH4 and NH3BH3 hydrolysis

    Galectin-3. One molecule for an alphabet of diseases, from A to Z

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    Galectin-3 (Gal-3) regulates basic cellular functions such as cell–cell and cell–matrix interactions, growth, proliferation, differentiation, and inflammation. It is not surprising, therefore, that this protein is involved in the pathogenesis of many relevant human diseases, including cancer, fibrosis, chronic inflammation and scarring affecting many different tissues. The papers published in the literature have progressively increased in number during the last decades, testifying the great interest given to this protein by numerous researchers involved in many different clinical contexts. Considering the crucial role exerted by Gal-3 in many different clinical conditions, Gal-3 is emerging as a new diagnostic, prognostic biomarker and as a new promising therapeutic target. The current review aims to extensively examine the studies published so far on the role of Gal-3 in all the clinical conditions and diseases, listed in alphabetical order, where it was analyzed

    Gene expression and pathway bioinformatics analysis detect a potential predictive value of MAP3K8 in thyroid cancer progression

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    Thyroid cancer is the commonest endocrine malignancy. Mutation in the BRAF serine/threonine kinase is the most frequent genetic alteration in thyroid cancer. Target therapy for advanced and poorly differentiated thyroid carcinomas include BRAF pathway inhibitors. Here, we evaluated the role of MAP3K8 expression as a potential driver of resistance to BRAF inhibition in thyroid cancer. By analyzing Gene Expression Omnibus data repository, across all thyroid cancer histotypes, we found that MAP3K8 is up-regulated in poorly differentiated thyroid carcinomas and its expression is related to a stem cell like phenotype and a poorer prognosis and survival. Taken together these data unravel a novel mechanism for thyroid cancer progression and chemo-resistance and confirm previous results obtained in cultured thyroid cancer stem cellsComment: 5 page

    Associative Search Network for RSSI-basedTarget Localization in Unknown Environments

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    International audienceReceived Signal Strength Indicator (RSSI) is commonly consideredand is very popular for target localization applications, since itdoes not require extra-circuitry and is always available on current devices.Unfortunately, target localizations based on RSSI are aected withmany issues, above all in indoor environments. In this paper, we focus onthe pervasive localization of target objects in an unknown environment.In order to accomplish the localization task, we implement an AssociativeSearch Network (ASN) on the robots and we deploy a real test-bedto evaluate the eectiveness of the ASN for target localization. The ASNis based on the computation of weights, to "dictate" the correct directionof movement, closer to the target. Results show that RSSI through anASN is eective to localize a target, since there is an implicit mechanismof correction, deriving from the learning approach implemented in theASN

    Correlating electron trapping and structural defects in Al2O3 thin films deposited by plasma enhanced atomic layer deposition

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    In this article, electron trapping in aluminum oxide (Al2O3) thin films grown by plasma enhanced atomic layer deposition on AlGaN/GaN heterostructures has been studied and a correlation with the presence of oxygen defects in the film has been provided. Capacitance–voltage measurements revealed the occurrence of a negative charge trapping effect upon bias stress, able to fill an amount of charge traps in the bulk Al2O3 in the order of 5 × 1012 cm−2. A structural analysis based on electron energy-loss spectroscopy demonstrated the presence of low-coordinated Al cations in the Al2O3 film, which is an indication of oxygen vacancies, and can explain the electrical behavior of the film. These charge trapping effects were used for achieving thermally stable (up to 100 °C) enhancement mode operation in AlGaN/GaN transistors, by controlling the two-dimensional electron gas depletion

    Radiolabeled PET/MRI Nanoparticles for Tumor Imaging

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    The development of integrated positron emission tomography (PET)/ magnetic resonance imaging (MRI) scanners opened a new scenario for cancer diagnosis, treatment, and follow-up. Multimodal imaging combines functional and morphological information from different modalities, which, singularly, cannot provide a comprehensive pathophysiological overview. Molecular imaging exploits multimodal imaging in order to obtain information at a biological and cellular level; in this way, it is possible to track biological pathways and discover many typical tumoral features. In this context, nanoparticle-based contrast agents (CAs) can improve probe biocompatibility and biodistribution, prolonging blood half-life to achieve specific target accumulation and non-toxicity. In addition, CAs can be simultaneously delivered with drugs or, in general, therapeutic agents gathering a dual diagnostic and therapeutic effect in order to perform cancer diagnosis and treatment simultaneous. The way for personalized medicine is not so far. Herein, we report principles, characteristics, applications, and concerns of nanoparticle (NP)-based PET/MRI CAs

    Molecular interactions, characterization and photoactivity of Chlorophyll a/chitosan/2-HP-β-cyclodextrin composite films as functional and active surfaces for ROS production

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    Novel photosensitizing film based on the natural hybrid polymer Chitosan/2-hydroxy-propyl-β-Cyclodextrin (CH/CD) is synthesized introducing Chlorophyll a (CH/CD/Chla) as a photoactive agent for possible application in antimicrobial photodynamic therapy (PDT). The polymer absorbs visible light, in turn able to generate reactive oxygen species (ROS) and, therefore it can be used as environmental friendly and biodegradable polymeric photosensitizer (PS). The modified film is characterized by means of different spectroscopic, calorimetric, diffraction techniques and microscopic imaging methods including time-resolved absorption spectroscopy. UV–Vis, FTIR-ATR and X-ray Photoelectron Spectroscopy (XPS) analyses suggest that Chla shows a strong affinity toward Chitosan introducing interactions with amino groups present on the polymer chains. Nanosecond laser flash photolysis technique provides evidence for the population of the excited triplet state of Chla. Photogeneration of singlet oxygen is demonstrated by both direct detection by using infrared luminescence spectroscopy and chemical methods based on the use of suitable traps. Scanning Electron Microscopy (SEM), Atomic Force Microscopy (AFM) and Differential Scanning Calorimetry (DSC) analyses confirm also the occurrence of structural changes both on the film surface and within the film layer induced by the insertion of the pigment. Moreover, X-ray Diffraction data (XRD) shows the existence of an amorphous phase for the chitosan films in all the compared conditions

    Highly Homogeneous 2D/3D Heterojunction Diodes by Pulsed Laser Deposition of MoS2 on Ion Implantation Doped 4H-SiC

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    In this paper, 2D/3D heterojunction diodes have been fabricated by pulsed laser deposition (PLD) of MoS2 on 4H-SiC(0001) surfaces with different doping levels, i.e., n(-) epitaxial doping (approximate to 10(16) cm(-3)) and n(+) ion implantation doping (>10(19) cm(-3)). After assessing the excellent thickness uniformity (approximate to 3L-MoS2) and conformal coverage of the PLD-grown films by Raman mapping and transmission electron microscopy, the current injection across the heterojunctions is investigated by temperature-dependent current-voltage characterization of the diodes and by nanoscale current mapping with conductive atomic force microscopy. A wide tunability of the transport properties is shown by the SiC surface doping, with highly rectifying behavior for the MoS2/n(-) SiC junction and a strongly enhanced current injection for MoS2/n(+) SiC one. Thermionic emission is found the dominant mechanism ruling forward current in MoS2/n(-) SiC diodes, with an effective barrier phi(B) = (1.04 +/- 0.09) eV. Instead, the significantly lower effective barrier phi(B) = (0.31 +/- 0.01) eV and a temperature-dependent ideality factor for MoS2/n(+) SiC junctions is explained by thermionic-field-emission through the thin depletion region of n(+) doped SiC. The scalability of PLD MoS2 deposition and the electronic transport tunability by implantation doping of SiC represents key steps for industrial development of MoS2/SiC devices

    Intraconal tumor-like mass as first manifestation of IgG4-related disease

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    A great variety of tumors and tumor-like lesions can involve the orbit. Benign and malignant neoplasms, inflammatory diseases, vascular and congenital lesions take part of this heterogeneous group that creates many challenges for diagnosis, management, and treatment. Obviously, symptoms and clinical history are fundamental to establish a differential diagnosis, and imaging is mandatory to distinguish between lesions that have similar clinical presentations in most cases. With this report, the authors highlight the diagnostic difficulties and the importance to include not only tumors but also vascular inflammatory process into the differential diagnosis of this unilateral orbital lesion type
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