Plasmonic-excitonic multi-hybrid glass-based nanocomposites incorporating Ag plus core-shell CdSe/CdS and alloyed CdSxSe1−x nanoparticles

Successful fabrication of glass-based hybrid nanocomposites (GHNCs) incorporating Ag, core-shell CdSe/CdS and CdS_xSe_1?x nanoparticles (NPs) is herein reported. Both metallic (Ag) and semiconductor (CdSe/CdS) NPs were pre-synthesized, suspended in colloids and added into the sol-gel reaction medium which was used to fabricate the GHNCs. During fabrication of the nanocomposites a fraction (20–60%) of core-shell CdSe/CdS NPs was alloyed into CdS_xSe_1?x (0.20 < x < 0.35) NPs without changing morphology. Modulation of in situ alloying is possible via the relative content of organics added into the sol-gel protocol. Within colloids Ag (core-shell CdSe/CdS) NPs presented average diameter and polydispersity index of 49.5 nm (4.2 nm) and 0.41 (0.21), respectively. On the other hand, the Ag (core-shell CdSe/CdS) NPs’ average diameter and polydispersity index assessed from the GHNCs were respectively 51.5 nm (4.1 nm) and 0.43 (0.25), revealing negligible aggregation of the nanophases within the glass template. The new GHNCs herein introduced presented two independent excitonic transitions associated to homogenously dispersed semiconductor NPs, peaking around 420 nm (core-shell CdSe/CdS) and 650 nm (CdS_xSe_1?x) and matching the plasmonic resonance (Ag NPs) in the 400–500 nm range. We envisage that the new GHNCs represent very promising candidates for superior light manipulation while illuminated with multiple laser beams in quantum interference-based devices.     

Recovery of polyphenols from camu-camu (Myrciaria dubia H.B.K. McVaugh) depulping residue by cloud point extraction

In this study the potential of cloud point extraction formed by a non-ionic surfactant was used in order to separate polyphenols from industrial residues of camu-camu. The effects of operational conditions of the cloud point extraction (CPE) on the polyphenol recovery and volumetric ratio were investigated. The results showed a maximum recovery of 95.71% that was obtained using 7.0 wt% Triton X-114, native pH (3.25), and 80 wt% polyphenol extract at 30 °C. The use of cloud point extraction was successful to recover the polyphenols from agroindustrial residue since it is a simple as well as of low-cost technique.     

Using Twitter® as source of information for dietary market research: a study on veganism and plant-based diets

Social media has experienced rapid growth in recent years and has been subjected of discussions on a wide range of topics including new lifestyles and eating habits, providing a great opportunity to obtain spontaneous consumer information. In this sense, the present work aimed to understand the perception of Twitter^® users about themes of veganism and plant-based diets. The social networking data mining methodology was applied to measure the relationship between both terms. The significant differences found were analysed using the global chi-square (χ²) test, and their sources of variation were investigated by the chi-square per cell. The results indicate that the vegan group's posts are more related to the categories of recipes, trends, criticism and negative comments about veganism, being more often citing sources when compared to the other group. The results of the plant-based diet group are more significantly related to the impacts of nutrition, physical activity and consumer health. In conclusion, Twitter^® has proved to be an interesting tool for obtaining data on (re) produced food publications on social media and their results can guide the market and the academic environment in creating new products, services and marketing strategies to answer the needs of specific consumers.     

Antioxidant Stability in Vegetable Oils Monitored by the ASTM D7545 Method

The PetroOXY method was used to evaluate the kinetics of oxidation of two edible vegetable oils, extracted from moringa and passion fruit. This method, which uses pure oxygen at 700 kPa is effective and fast and our experiments were carried out at temperatures 110–140 °C with BHA antioxidant additive concentration ranging from 0 to 500 ppm. Moringa and passion fruit oils followed first-order kinetics although, in the case of passion fruit oil, mathematical approximations in the first-order kinetic expression resulted in a final equation that could also be interpreted as deriving from zero-order kinetics. The higher stability of moringa oil was characterized by an activation enthalpy ca. 50 % higher than the one related to passion fruit oil.     

N-acryloxysuccinimide: Synthesis, characterization, and incorporation in dental adhesives

In an attempt to enrich the world of dentistry through the development of new materials, this study proposes to synthesize and incorporate a monomer containing the N-hydroxysuccinimide (NHS) ester reactive group to a dental adhesive. As such, this study developed a simple method to obtain NHS esters by employing acrylic acid (AA) and NHS in the presence of EDC (N-ethyl-N′-(3-dimethylaminopropyl)carbodiimide), from an aprotic medium. The experimental N-acryloxysuccinimide (NSA) monomer was analyzed by infrared spectroscopy (FTIR) and nuclear magnetic resonance of hydrogen (¹H NMR). This monomer was then incorporated within a prepared dental adhesive, in a 5% proportion. The modified adhesive, containing NSA, was applied to the dental surface of bovine teeth to obtain an adhesive/dentin interface in vitro. The characterization of this interface by Raman spectroscopy presented the formation of new amide bonds. Moreover, through scanning electron microscopy (SEM), it became possible to observe an intense penetration of this modified adhesive on the dental surface. Considering the outcome, it can be concluded that the synthesized NSA monomer provided a favorable condition for the dental adhesives to interact chemically with the dentin collagen fibers.     

Synthesis of higher alcohols with cobalt and copper based model catalysts: effect of the alkaline metals

The synthesis of higher alcohols, obtained from CO hydrogenation over transition metals, is an alternative for the production of chemical commodities and less pollutant renewable fuels nowadays. In this work, the influence of different alkali metals (Li, Na, K, Cs) over the formation of active phases of supported catalysts, based on cobalt and copper, as well as the performance of these solids in the reaction of CO hydrogenation under a 50 bar pressure were studied. The solids were prepared by continuous coprecipitation of sodium carbonate with metal nitrate solutions (Al–Co, Al–Cu or Al–Co–Cu) promoted with the alkali metals with dry impregnation. Characterization studies by atomic absorption spectrophotometry, BET, XPS and also the results of catalytic tests show that physico-chemical properties of the obtained catalyst are similar to those of the industrial catalyst used as reference (I).     

Anticoagulant, Antioxidant and Antitumor Activities of Heterofucans from the Seaweed Dictyopteris delicatula

In the present study, six families of sulfated polysaccharides were obtained from seaweed Dictyopteris delicatula by proteolytic digestion, followed by acetone fractionation and molecular sieving on Sephadex G-100. Chemical analyses demonstrated that all polysaccharides contain heterofucans composed mainly of fucose, xylose, glucose, galactose, uronic acid, and sulfate. The fucans F0.5v and F0.7v at 1.0 mg/mL showed high ferric chelating activity (～45%), whereas fucans F1.3v (0.5 mg/mL) showed considerable reducing power, about 53.2% of the activity of vitamin C. The fucan F1.5v presented the most prominent anticoagulant activity. The best antiproliferative activity was found with fucans F1.3v and F0.7v. However, F1.3v activity was much higher than F0.7v inhibiting almost 100% of HeLa cell proliferation. These fucans have been selected for further studies on structural characterization as well as in vivo experiments, which are already in progress.     

Development of a microwave-assisted digestion method using ICP-OES to measure metals in gum deposits of internal combustion engines

The heterogeneous nature of gum samples obtained from the deposits of internal combustion engines is the main difficulty in accurate determination of their metal content. A microwave-assisted digestion method was implemented using factorial experimental design. The optimization of this procedure was carried out by first evaluating the effects of variables on the response (i.e., the residual carbon content or RCC). The variables of maximum heating power, heating time and nitric acid volume were studied. The RCC response was measured by inductively coupled plasma optical emission spectrometry (ICP-OES). The time of maximum heating power was essential to obtain a desired RCC. The surface response was constructed with optimal conditions presented at 6 min and heating power of 700 W. Amounts of aluminum (Al), calcium (Ca), copper (Cu), iron (Fe), magnesium (Mg), manganese (Mn), nickel (Ni), lead (Pb) and zinc (Zn) were determined in 26 gum samples by ICP-OES. Ca, Fe, Mg and Zn were found at mg g⁻¹ levels in the samples, while Al, Cu, Mn, Ni and Pb were found at mg kg⁻¹ levels. Principal component analysis (PCA) was used to establish a correlation between the gum samples and the different metal contents. Three distinct groups were separated according to the characteristics of the collected samples.