248 research outputs found

    Component-resolved diagnosis of hazelnut allergy in children

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    Hazelnuts commonly elicit allergic reactions starting from childhood and adolescence, with a rare resolution over time. The definite diagnosis of a hazelnut allergy relies on an oral food challenge. The role of component resolved diagnostics in reducing the need for oral food challenges in the diagnosis of hazelnut allergies is still debated. Therefore, three electronic databases were systematically searched for studies on the diagnostic accuracy of specific-IgE (sIgE) on hazelnut proteins for identifying children with a hazelnut allergy. Studies regarding IgE testing on at least one hazelnut allergen component in children whose final diagnosis was determined by oral food challenges or a suggestive history of serious symptoms due to a hazelnut allergy were included. Study quality was assessed by the Quality Assessment of Diagnostic Accuracy Studies-2 tool. Eight studies enrolling 757 children, were identified. Overall, sensitivity, specificity, area under the curve and diagnostic odd ratio of Cor a 1 sIgE were lower than those of Cor a 9 and Cor a 14 sIge. When the test results were positive, the post-test probability of a hazelnut allergy was 34% for Cor a 1 sIgE, 60% for Cor a9 sIgE and 73% for Cor a 14 sIgE. When the test results were negative, the post-test probability of a hazelnut allergy was 55% for Cor a 1 sIgE, 16% for Cor a9 sIgE and 14% for Cor a 14 sIgE. Measurement of IgE levels to Cor a 9 and Cor a 14 might have the potential to improve specificity in detecting clinically tolerant children among hazelnut-sensitized ones, reducing the need to perform oral food challenges

    Report on advances for pediatricians in 2018: allergy, cardiology, critical care, endocrinology, hereditary metabolic diseases, gastroenterology, infectious diseases, neonatology, nutrition, respiratory tract disorders and surgery.

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    This review reported notable advances in pediatrics that have been published in 2018. We have highlighted progresses in allergy, cardiology, critical care, endocrinology, hereditary metabolic diseases, gastroenterology, infectious diseases, neonatology, nutrition, respiratory tract disorders and surgery. Many studies have informed on epidemiologic observations. Promising outcomes in prevention, diagnosis and treatment have been reported. We think that advances realized in 2018 can now be utilized to ameliorate patient car

    Partial Hydrogenation of Soybean and Waste Cooking Oil Biodiesel over Recyclable-Polymer-Supported Pd and Ni Nanoparticles

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    Biodiesel obtained through the transesterification in methanol of vegetable oils, such as soybean oil (SO) and waste cooking oil (WCO), cannot be used as a biofuel for automotive applications due to the presence of polyunsaturated fatty esters, which have a detrimental effect on oxidation stability (OS). A method of upgrading this material is the catalytic partial hydrogenation of the fatty acid methyl ester (FAME) mixture. The target molecule of the partial hydrogenation reaction is monounsaturated methyl oleate (C18:1), which represents a good compromise between OS and the cold filter plugging point (CFPP) value, which becomes too high if the biodiesel consists of unsaturated fatty esters only. In the present work, polymer-supported palladium (Pd-pol) and nickel (Ni-pol) nanoparticles were separately tested as catalysts for upgrading SO and WCO biodiesels under mild conditions (room temperature for Pd-pol and T = 100◦ C for Ni-pol) using dihydrogen (p = 10 bar) as the reductant. Both catalysts were obtained through co-polymerization of the metal containing monomer M(AAEMA)2 (M = Pd, Ni; AEEMA− = deprotonated form of 2-(acetoacetoxy)ethyl methacrylate)) with co-monomers (ethyl methacrylate for Pd and N,N-dimethylacrilamide for Ni) and cross-linkers (ethylene glycol dimethacrylate for Pd and N,N’-methylene bis-acrylamide for Ni), followed by reduction. The Pd-pol system became very active in the hydrogenation of C=C double bonds, but poorly selective towards the desirable C18:1 product. The Ni-pol catalyst was less active than Pd-pol, but very selective towards the mono-unsaturated product. Recyclability tests demonstrated that the Ni-based system retained its activity and selectivity with both the SO and WCO substrates for at least five subsequent runs, thus representing an opportunity for waste biomass valorization

    . Microwave-assisted solvothermal controlled synthesis of Fe-Co

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    Syntheses of bimetallic cobalt-iron-based nanoparticles starting from Co(acac)2 and Fe(acac)3 (acac = acetylacetonate) were carried out by microwave-assisted solvothermal process, using ethylene glycol as the solvent and (polyvinylpyrrolidone) PVP, as the stabilizer. Indeed, the reaction mechanism in the presence of ethylene glycol is well understood [1] with the role of PVP being the inhibition of nanoparticles growth [2]. However, the control of the morphology of the synthetized nanoparticles is still a great challenge. Herein, we demonstrated that by adding amines to the reaction mixture, it is possible to control the morphology of the prepared bimetallic cobalt-iron materials. Thus, different Co-Fe micro-composites were synthetized by an innovative microwave assisted solvothermal synthesis, which allows to considerably reduce reaction time from 12 h to 15 min, with respect to classical thermal methods. The procedure was optimized by varying several parameters, such as: amount of PVP, in the presence or in the absence of amines, reaction temperature. The dark brown obtained powders were characterized by scanning electron microscopy, infrared spectroscopy and thermogravimetric analysis, confirming the beneficial effect of the presence of the amine in the morphology of the obtained composites. The obtained results open a new scenario for further studies on the possibility to control the morphology of bimetallic composite materials. [1] Fievet F, Lagier J P and Figlarz M Mater. Res. Soc. Bull. 24 (1989) 29–34 [2] Teranishi T, Kurita R and Miyake M J. Inorg. Organometall. Polym. 10 (2000) 145–5

    Polyacetylenes Bearing Chiral-Substituted Fluorene and Terfluorene Pendant Groups: Synthesis and Properties

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    The synthesis of the first polyacetylenes bearing chiral fluorene-based pendant groups is described. Poly{9,9-bis[(S)-3,7-dimethyloctyl]fluoren-2-ylacetylene} (PFA1), poly{9,9-bis[(S)-2-methylbutyl]- fluoren-2-ylacetylene} (PFA2), and poly{9,9,9′,9′,9′′,9′′-hexakis[(S)-2-methylbutyl]-7,2′;7′,2′′-terfluoren- 2-ylacetylene} (PFA3) have been obtained by Rh(I)-catalyzed polymerization of the corresponding terminal acetylene monomers 2-ethynyl-9,9-bis[(S)-3,7-dimethyloctyl]fluorene (2a), 2-ethynyl-9,9-bis[(S)-2-methylbutyl]fluorene (2b), and 2-ethynyl-9,9,9′,9′,9′′,9′′-hexakis[(S)-2-methylbutyl]-7,2′;7′,2′′-terfluorene (10). The effect of the alkyl chain length at the C-9 position of fluorene on the structural and conformational aspects of the polymers PFA1 and PFA2 as well as on their chiroptical properties was studied by XRD, DSC, TGA, GPC, UV-vis, and CD. A more planar conformation of the polyenic backbone of PFA1 with respect to PFA2 can be inferred by a red shift of the ð-ð* transition in the UV-vis spectra. Their photoluminescence properties are those typical of fluorene systems. CD measurements evidenced Cotton effects of opposite signs in correspondence of the backbone absorption region, ascribable to an excess of a screw sense of the helical conformations assumed by the two polymers. PFA3 revealed an amorphous structure and exhibited peculiar thermal stability features (as indicated by TGA and DSC). Its emission spectra interest the violet-blue region and do not show any substantial red shift passing from solution to solid state, thus pointing out an aggregation prevention of terfluorene groups by means of the polyacetylene backbone

    How calcination affects the morphology and the catalytic activity of polymer supported Nickel

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    A nickel containing monomer, Ni(AAEMA)2 (AAEMA = deprotonated form of 2-(acetoacetoxy) ethyl methacrylate) was co-polymerized with ethyl methacrylate (co-monomer) and ethylene glycol dimethacrylate (cross-linker) [1]. The obtained polymer was a green methacrylic resin containing Ni(II) centers homogeneously dispersed in the catalyst, which resulted insoluble in all common organic solvents and in water. The material can be described as an amphiphilic resin, air and moisture stable, with the peculiarity to swell in halogenated solvents, acetone and water and to shrink in diethyl ether and petroleum ether. The polymer was calcined under reductive conditions (dihydrogen with initial pressure of 5 bar) following two procedures, differing from each other for the cooling conditions. In the first procedure the calcined material was cooled under dihydrogen gas, while in the second one the cooling step occurred under air. After calcination, the green Ni(II) based co-polymer turned into black resins, Ni-res1 (obtained with hydrogen cooling) and Ni-res2 ((obtained with air cooling). TEM analyses showed that both Ni-res1 and Ni-res2 supported Ni nanoparticles with different morphologies, being the metal nanoparticles onto Ni-res1 smaller than the ones dispersed in Ni-res2, that had an urchin-like shape. Both Ni based co-polymers were tested as catalysts in the reduction of nitrobenzene with NaBH4 [2]. Ni-res1 resulted more active and selective towards aniline, with respect to Ni-res2. [1] M.M. Dell’Anna, G. Romanazzi, P. Mastrorilli, Curr. Org. Chem. 17 (2013) 1236 [2] A.M. Fiore, G. Romanazzi, M.M. Dell’Anna, M. Latronico, C. Leonelli, A. Rizzuti, M. Mali, P. Mastrorilli, Mol. Catal. 476 (2019) 11050

    Report on advances for pediatricians in 2018: Allergy, cardiology, critical care, endocrinology, hereditary metabolic diseases, gastroenterology, infectious diseases, neonatology, nutrition, respiratory tract disorders and surgery

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    This review reported notable advances in pediatrics that have been published in 2018. We have highlighted progresses in allergy, cardiology, critical care, endocrinology, hereditary metabolic diseases, gastroenterology, infectious diseases, neonatology, nutrition, respiratory tract disorders and surgery. Many studies have informed on epidemiologic observations. Promising outcomes in prevention, diagnosis and treatment have been reported. We think that advances realized in 2018 can now be utilized to ameliorate patient care

    Microwave-assisted solvothermal synthesis of fe3o4/ceo2 nanocomposites and their catalytic activity in the imine formation from benzyl alcohol and aniline

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    Fe3O4/CeO2 nanocomposites were synthetized by coating magnetite seeds of different morphologies (hexagonal, spheroidal, quasi-spherical) with ceria, in ethylene glycol as solvothermal solvent. The synthesis was performed in the presence of microwave irradiation aiming to overcome the common disadvantages proper of the classic solvothermal/hydrothermal procedure. The obtained nanocomposites were calcined at the optimum temperature of 550 °C. The structure of the new nanomaterials was carefully investigated by IR, XRD, SEM, EDS and TEM analyses. The nanocomposites resulted to be constituted by CeO2 nanoparticles distributed onto Fe3O4 seeds, that kept their pristine morphology. The new materials were used as catalysts for imine synthesis from benzyl alcohol and aniline. The highest imine conversion rate was obtained with Fe3O4/CeO2, which was synthesized from Fe3O4 nanoparticles (hexagonal) obtained by microwave hydrothermal procedure in the absence of any organic additive (polyvinylpyrrolidone, trisodium citrate dihydrate or oleic acid). The catalyst could be easily removed from the reaction mixture with the help of an external magnet, and it was recycled for at least five runs with increasing catalytic activit

    Microwave-assisted solvothermal synthesis of fe3o4/ceo2 nanocomposites and their catalytic activity in the imine formation from benzyl alcohol and aniline

    Get PDF
    Fe3O4/CeO2 nanocomposites were synthetized by coating magnetite seeds of different morphologies (hexagonal, spheroidal, quasi-spherical) with ceria, in ethylene glycol as solvothermal solvent. The synthesis was performed in the presence of microwave irradiation aiming to overcome the common disadvantages proper of the classic solvothermal/hydrothermal procedure. The obtained nanocomposites were calcined at the optimum temperature of 550 °C. The structure of the new nanomaterials was carefully investigated by IR, XRD, SEM, EDS and TEM analyses. The nanocomposites resulted to be constituted by CeO2 nanoparticles distributed onto Fe3O4 seeds, that kept their pristine morphology. The new materials were used as catalysts for imine synthesis from benzyl alcohol and aniline. The highest imine conversion rate was obtained with Fe3O4/CeO2, which was synthesized from Fe3O4 nanoparticles (hexagonal) obtained by microwave hydrothermal procedure in the absence of any organic additive (polyvinylpyrrolidone, trisodium citrate dihydrate or oleic acid). The catalyst could be easily removed from the reaction mixture with the help of an external magnet, and it was recycled for at least five runs with increasing catalytic activity
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