Improved photocatalytic properties of doped titanium-based nanometric oxides

Photocatalysis is considered one of the most promising technologies for applications in the environmental field especially in the abatement of water-soluble organic pollutants. In this field, titanium dioxide nanoparticles have drawn much attention recently; however, the use of this oxide presents some limitation since it allows to obtain high photoresponse and degradation efficiency only under UV light irradiation, that represents the 3 to 4% of the solar radiation, so preventing its environmental large-scale applications under diffuse daylight. In this work the photocatalytic efficiencyoftitanium-based oxides systems containing alkaline earth metals such as barium and strontium, prepared by a simple sol-gel method was investigated, evaluating the degradation of methylene blue as model compound under UV and visible light irradiation. The results were compared with those obtained with Degussa P25 titanium dioxide. The achieved degradation percentage of methylene blue are very promising showing that under visible light irradiation it is possible to obtain a maximum dye removal percentage ~ 50 % higher than that obtained with the Degussa P25

Efficient utilization of Al2O3 as structural promoter of Fe into 2 and 3 steps chemical looping hydrogen process. Pure H2 production from ethanol

Chemical Looping Hydrogen (CLH) allows the direct production of pure hydrogen exploiting the redox properties of Fe, with high flexibility on the type of reductant used. In this work, a highly pure hydrogen stream suitable for the direct use into Proton Exchange membrane Fuel Cells was produced, using bioethanol as renewable fuel. The influence of both redox temperature (675°C–750 °C) and chemical composition of the Fe-based particles (2 wt% and 40 wt% of alumina added) on the carbon formation rate during reduction step was also deeply analyzed. Al2O3 changed both FexOy redox kinetics and equilibrium phases, leading to a complete iron deactivation at high Al2O3 concentration. The addition of an air oxidation step (3 steps CLH) is fundamental to restore the redox activity, with a constant efficiency of about 30% at 750 °C for 10 cycles. Furthermore, Al2O3 promotes the ethanol conversion into carbon, undermining the hydrogen purity

Primary resistance of HIV to antiretrovirals among individuals recently diagnosed at voluntary counselling and testing centres in the metropolitan region of Recife, Pernambuco

Determining the prevalence and type of antiretroviral (ARV) resistance among ARV-naïve individuals is important to assess the potential responses of these individuals to first-line regimens. The prevalence of primary resistance and the occurrence of recent infections among individuals with human immunodeficiency virus (HIV)/acquired immune deficiency syndrome (AIDS) were identified among recently diagnosed patients at five sexually transmitted disease/AIDS testing and counselling centres in the metropolitan region of Recife (RMR), Pernambuco, Brazil, between 2007-2009. One-hundred and eight samples were analysed using the Calypte® BED assay. Males predominated (56%), as did patients aged 31-50 years. Twenty-three percent presented evidence of a recent HIV infection. The median CD4+ T lymphocyte count was 408 cells/mm³ and the median viral load was 3.683 copies/mL. The prevalence of primary resistance was 4.6% (confidence interval 95% = 1-8.2%) based on criteria that excluded common polymorphisms in accordance with the surveillance drug resistance mutation criteria. The prevalence of resistance to non-nucleoside reverse transcriptase, nucleoside/nucleotide reverse transcriptase and protease inhibitors were 3.8%, 1.5% and 0.8%, respectively. Fifty-seven percent of strains were from clade B, 37.7% were clade F and 3.1% were clade C; there were no statistically significant differences with respect to resistance between clades. Recent infection tended to be more common in men (p = 0.06) and in municipalities in the south of the RMR (Jaboatão dos Guararapes and Cabo de Santo Agostinho) (p = 0.046). The high prevalence of recent infection and the high prevalence of non-B strains in this poor Brazilian region merit further attention.Laboratório Central de Saúde Pública de Pernambuco Setor de VirologiaUniversidade Federal de Pernambuco Programa de Pós-Graduação em Medicina TropicalFiocruz Centro de Pesquisa Aggeu MagalhãesCentro de Testagem e Aconselhamento Herbert de SouzaUniversidade Federal de São Paulo (UNIFESP) Laboratório de RetrovirologiaUNIFESP, Laboratório de RetrovirologiaSciEL

Effect of yerba mate (Ilex paraguariensis) residue and coupling agent on the mechanical and thermal properties of polyolefin‐based composites

In this study, the feasibility of giving added value to spent yerba mate residues by manufacturing thermoplastic composites, and their potential benefits, is investigated. Experimental tests performed on yerba mate residues demonstrated that such residue, after a simple extraction procedure by water/ethanol solution, showed an acceptable level of interfacial compatibility with polyolefins. Biocomposites at different yerba mate residue amount in polypropylene and high-density polyethylene (HDPE) were produced by a two-stage process, involving extrusion and injection molding, and their mechanical and thermal properties were evaluated through tensile, TGA, and DSC tests, respectively. The addition of yerba mate residues resulted in a significant improvement (up to 23% when 20 wt% of filler was added to HDPE) of tensile properties compared to the neat matrices. This result was obtained without showing a positive effect on their crystallization behavior, as found from DSC results. Composite materials modified with maleic anhydride as coupling agent exhibited an even greater reinforcing efficiency due to enhanced interfacial compatibility. Basing on the results of this study, yerba mate residue/thermoplastic composites appear to be a viable alternative to wood composite materials, with associated environmental benefits related to the valorization of such agro-food waste

Piezo-resistive properties of graphene based PVDF composite films for strain sensing

Graphene based polyvinylidene fluoride (PVDF)composite films have been produced and characterized in orderto investigate their piezo-resistive properties. To this purpose, anew production process has been developed, with the aim offabricating at low cost PVDF films filled with graphenenanoplatelets (GNPs). The produced films, having a GNPcontent of 1.5%wt and 2% wt, have been characterized frommorpholocial and chemical points of view. Moreover, theirpiezo-resistive properties have been investigated both in staticand cyclic conditions. The produced films show a stable andrepeatable response to the applied strain. A sensitivity of 15 hasbeen measured for the PVDF/GNP film filled at 1.5% wt,corresponding to an applied strain of 1.5

Graphite Nanoplatelets and <i>Caenorhabditis elegans</i>: Insights from an <i>in Vivo</i> Model

We evaluated the toxicity of graphite nanoplatelets (GNPs) in the model organism <i>Caenorhabditis elegans</i>. The GNPs resulted nontoxic by measuring longevity as well as reproductive capability end points. An imaging technique based on Fourier transform infrared spectroscopy (FT-IR) mapping was also developed to analyze the GNPs spatial distribution inside the nematodes. Conflicting reports on the <i>in vitro</i> antimicrobial properties of graphene-based nanomaterials prompted us to challenge the host–pathogen system <i>C. elegans–Pseudomonas aeruginosa</i> to assess these findings through an <i>in vivo</i> model