556 research outputs found
Human case of West Nile neuroinvasive disease in Portugal, summer 2015
A case of West Nile virus (WNV) infection was reported in the Algarve region, Portugal, in the first week of September 2015. WNV is known to circulate in Portugal, with occasional reports in horses and birds (2004 to 2011) and very sporadically human cases (in 2004 and in 2010). Here we present the clinical and laboratory aspects related to the first human case of West Nile neuroinvasive disease reported in Portugal
Depth of cure of bulk-fill light cured composite resins with different initiators
Poster presented at the 3rd International Congress of CiiEM - Research and Innovation in Human and Health Sciences, Monte da Caparica, Portugal, 20-22 June 2018N/
General synthetic approach to 2-phenolic adenine derivatives
A simple and general âone potâ procedure for the synthesis of 2,9-diarylpurines with one or multiple hydroxyl groups in the 2- aryl unit is described, from the reaction of 5-amino-4-amidinoimidazoles with phenolic aldehydes.National NMR Network, Fundação para a CiĂȘncia e a Tecnologia (FCT). F.C.T. (project nÂșF-COMP-01-0124-FEDER-022716 (ref. FCT PEst-/QUI/UI0686/2011) FEDER-COMPETE, FCT-Portugal and the PhD grant to C. Correia (SFRH/BD/22270/2005)
Few-layer graphene aqueous suspensions for polyurethane composite coatings
Graphite nanoplates (GnP) have recently attracted attention as an economically viable alternative for the development of functional and structural nanocomposites. The incorporation of GnP into waterborne polyurethane (WPU) with loadings from 0.1 to 10 wt.% was studied. The mechanical properties of the composite films were assessed by tensile testing showing an increase of the Youngâs modulus up to 48%. The electrical conductivity increased by 9 orders of magnitude and the water vapor permeability of the composite films decreased 57% for composites containing 5.0 wt.% of GnP.The authors acknowledge FCT, project PEst-C/CTM/LA0025/2015 and PhD grant
SFRH/BD/87214/2012.info:eu-repo/semantics/publishedVersio
Functionalization of CNTS with maleic anhydride
The outstanding properties of carbon nanotubes (CNTs) [1] are mainly related with their unique structural features. However, the high Ï-Ï staking between the tubes is a major drawback for their manipulation and interaction with other materials. Chemical functionalization has been used as a convenient tool to improve their performance in various applications [2].
The work reports the functionalization of multi-wall carbon nanotubes (MWCNTs) with maleic anhydride via a Diels-Alder addition reaction, performed in dimethyl sulfoxide (190 ÂșC) or 2-chorotoluene (150 ÂșC) for 24 hours. The product was characterized by thermogravimetric analysis (TGA) and the weight loss at 800 ÂșC was 11.9 and 3.7 % respectively. Potentiometric titration suggests that CNTs modified at 190 ÂșC remain predominantly in the anhydride form, while for CNTs modified at 150 ÂșC, the extent of hydrolysis is approximately 40 %. Maleic anhydride was also reacted with a model compound (anthracene) in dimethyl sulfoxide (190 ÂșC) and the hydrolysis of the product (0.025 mmol in 650 ”L of DMSO-d6) was followed by 1H RMN upon addition of 0.166 mmol of DCl (40 % weight in D2O) (graphic in figure). The anhydride 1 was easily regenerated from the dicarboxylic acid 2 when this compound was heated at 185 ÂșC for 10 minutes. A similar behavior is expected for the modified CNTs.Fundação para a CiĂȘncia e Tecnologi
Electrochemical sensing using carboxylated multiwalled carbon nanotubes
Carbon nanotubes (CNTs) have demonstrated great advantages in electrochemistry. The application of CNTs
most widely employed so far has been the construction of various detection devices, such as gas sensors,
electrochemical detectors and biosensors [1]. The main advantage of their use is related to the increase of the
electrodes surface area and of the electron transfer rates, improving sensors sensitivity. Besides, their sorption
capability of different analytes can be used to improve sensors selectivity [2]. (...
A posteriori error estimation for second-order optimally convergent G/XFEM
This work presents a ZZ-BD a posteriori error estimator tailored for 3-D linear elastic fracture mechanics problems that are approximated by second-order pFEM-GFEM formulations. The proposed error estimator is shown to estimate well discretization errors in the energy norm, with the estimated discretization error converging at the same rate as the exact discretization error. Also, the computed effectivity indexes are close to the optimal value of 1 for a LEFM problem that exhibits 3-D effects
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