26 research outputs found

    Mesoporous iron-titania catalyst for cyclohexane oxidation

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    This is the first report of using ultrasound radiation for depositing a nanosized catalyst (iron oxide) into the pores of a mesoporous material (titania); the resulting catalyst is used for the oxidation of cyclohexane under mild conditions

    Detection of human neutrophil elastase (HNE) on wound dressings as marker of inflammation

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    Chronic wound fluids have elevated concentration of human neutrophil elastase (HNE) which can be used as inflammation/infection marker. Our goal is to develop functional materials for fast diagnosis of wound inflammation/infection by using HNE as a specific marker. For that, fluorogenic peptides with a HNE-specific cleavage sequence were incorporated into traditional textile dressings, to allow real-time detection of the wound status. Two different fluorogenic approaches were studied in terms of intensity of the signal generated upon HNE addition: a fluorophore 7-amino-4-trifluormethylcoumarin (AFC) conjugated to a HNE-specific peptide and two fluorophore/quencher pairs (FAM/Dabcyl and EDANS/Dabcyl) coupled to a similar peptide as a Förster resonance energy transfer (FRET) strategy. Also, two immobilization methods were tested: sonochemistry immobilization onto a cotton bandage and glutaraldehyde (GTA)-assisted chemical crosslinking onto a polyamide dressing. The immobilized fluorogenic AFC peptide showed an intense fluorescence emission in the presence of HNE. HNE also induced an enhanced fluorescent signal with the EDANS/Dabcyl FRET peptide which showed to be a more sensitive and effective strategy than the AFC peptide. However, its chemical immobilization onto the polyamide dressing greatly decreased its detection, mainly due to the more difficult access of the enzyme to the cleavage sequence of the immobilized peptide. After optimization of the in situ immobilization, it will be possible to use these fluorescence-functionalized dressings for an effective and specific monitoring of chronic wounds by simply using a portable ultraviolet (UV) light source. We envision that the development of this point-of-care medical device for wound control will have a great impact on patients life quality and reduction of costs on health care system.This study was funded by the European project InFact-Functional materials for fast diagnosis of wound infection (FP7-NMP-2013-SME-7-grant agreement no. 604278). The work done at Centre of Biological Engineering (CEB) was also supported by the Portuguese Foundation for Science and Technology (FCT) under the scope of the strategic funding of UID/BIO/04469/2013 unit, COMPETE 2020 (POCI-01-0145-FEDER-006684) and BioTecNorte operation (NORTE-01-0145-FEDER-000004) funded by European Regional Development Fund under the scope of Norte 2020-Programa Operacional Regional do Norte

    Bifunctional Carbon Dots—Magnetic and Fluorescent Hybrid Nanoparticles for Diagnostic Applications

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    There is a huge demand for materials capable of simple detection or separation after conjugation with specific biologic substances when applied as a diagnostic tools. Taking into account the photoluminescence properties of C-dots and the highly magnetic properties of Fe(0), a new hybrid composite of these components was synthesized via ultrasound irradiation. The material was fully characterized by various physicochemical techniques. The main goal of the current study was to obtain a highly magnetic and intense fluorescent hybrid material. The goal was achieved. In addition, magnetic particles tended to agglomerate. The new hybrid can be suspended in ethanol, which is an additional feature of the current research. The dispersion of the hybrid nanoparticles in ethanol was achieved by utilizing the interaction of iron particles with C-dots which were decorated with functional groups on their surface. The newly formed hybrid material has potential applications in diagnostic by conjugating with specific antibodies or with any other biologic compounds. Such application may be useful in detection of various diseases such as: cancer, tuberculosis, etc

    Oxidation of cyclohexane with nanostructured amorphous catalysts under mild conditions

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    The oxidation of cyclohexane with molecular oxygen (1 atm) in the presence of isobutyraldehyde catalyzed by nanostructured iron and cobalt oxides and iron supported on titania has been studied. It was found that highly dispersed transition metals oxide is more effective for oxidation than the corresponding zero valent powders. In the titania supported catalysts iron exists as iron (III) oxide segregated to the surface layers and stabilized by titania. This form is the most active in the cyclohexane oxidation under mild conditions

    Work in progress 1992

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    Published jointly with the Economic and Social Research CouncilAvailable from British Library Document Supply Centre- DSC:MFE 1169(CH--92.1076)(microfiche) / BLDSC - British Library Document Supply CentreSIGLEGBUnited Kingdo

    Sonochemical co-deposition of antibacterial nanoparticles and dyes on textiles

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    The sonochemical technique has been already proven as one of the best coating methods for stable functionalization of substrates in a broad range of applications. Here, we report for the first time on the simultaneous sonochemical dyeing and coating with antibacterial metal oxide (MO) nanoparticles of textiles. In this one-step process the antibacterial nanoparticles are synthesized in-situ and deposited together with dye nanoparticles on the fabric surface. It was shown that the antibacterial behavior of the metal oxides was not influenced by the presence of the dyes. Higher K/S values were achieved by sonochemical deposition of the dyes in comparison to a dip-coating (exhaustion) process. The stability of the antibacterial properties and the dye fastness was studied for 72 hours in saline solution aiming at medical applicationsPeer Reviewe

    Sociology of Law in France: from two sociologies to interdisciplinarity

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    peer reviewedLa sociologie du droit en France, au même titre que la sociologie juridique dans n’importe quel autre pays, est déterminée par les conditions historiques dans lesquelles le champ juridique s’est construit ainsi que par les relations qui se sont établies entre le droit, le pouvoir politique et l’Etat. Cet article propose de présenter les enjeux auxquels fait face la sociologie du droit en portant une attention particulière au contexte social et politique dans lequel elle s’est développée au sein de l’Hexagone. Cet article pose l’hypothèse d’une faible institutionnalisation de la sociologie du droit dans ce pays, que nous proposons d’expliquer par sa construction historique « à l’ombre du droit », ainsi que par l’éclatement des différents groupes, courants et tendances qui la composent à l’heure actuelle

    Antibacterial and In Vivo Studies of a Green, One-Pot Preparation of Copper/Zinc Oxide Nanoparticle-Coated Bandages

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    Simultaneous water and ethanol-based synthesis and coating of copper and zinc oxide (CuO/ZnO) nanoparticles (NPs) on bandages was carried out by ultrasound irradiation. High resolution-transmission electron microscopy demonstrated the effects of the solvent on the particle size and shape of metal oxide NPs. An antibacterial activity study of metal-oxide-coated bandages was carried out against Staphylococcus aureus (Gram-positive) and Escherichia coli (Gram-negative). CuO NP-coated bandages made from both water and ethanol demonstrated complete killing of S. aureus and E. coli bacteria within 30 min., whereas ZnO NP-coated bandages demonstrated five-log reductions in viability for both kinds of bacteria after 60 min of interaction. Further, the antibacterial mechanism of CuO/ZnO NP-coated bandages is proposed here based on electron spin resonance studies. Nanotoxicology investigations were conducted via in vivo examinations of the effect of the metal-oxide bandages on frog embryos (teratogenesis assay—Xenopus). The results show that water-based coatings resulted in lesser impacts on embryo development than the ethanol-based ones. These bandages should therefore be considered safer than the ethanol-based ones. The comparison between the toxicity of the metal oxide NPs prepared in water and ethanol is of great importance, because water will replace ethanol for bulk scale synthesis of metal oxide NPs in commercial companies to avoid further ignition problems. The novelty and importance of this manuscript is avoiding the ethanol in the typical water:ethanol mixture as the solvent for the preparation of metal oxide NPs. Ethanol is ignitable, and commercial companies are trying the evade its use. This is especially important these days, as the face mask produced by sonochemistry (SONOMASK) is being sold all over the world by SONOVIA, and it is coated with ZnO

    Silica supported nitrogen-enriched porous benzimidazole-linked and triazine based polymers for the adsorption of CO2

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    Two crystalline and five amorphous benzimidazole polymers (BINP) were synthesized and conjugated to porous silica via amine and aldehyde-based materials by a simple reflux procedure. The resulting polymers were subject to thermal analysis for monitoring and quantification of the adsorption and desorption of CO2. All the polymers were capable of adsorbing CO2 from a flowing stream of only 80 mL/min at 25 oC. The adsorbed CO2 onto the polymers were effectively desorbed at room temperature, illustrating the potential application of such polymers for repeated adsorption/desorption of CO2. The CO2 adsorption capacities of these polymers were dependent upon their nitrogen content, specific surface area, and pore size. The available nitrogen atoms for binding to the carbon of CO2 via tetrel bonds also plays an important role in the capture of this gas. Minimal and much lower CO2 adsorption was also noted with two crystalline polymers, compared to the five amorphous counterparts. Intermolecular hydrogen bonding and π-π interaction effectively prevented the polymer N sites of the crystalline polymers from interacting with polarized CO2 molecules
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