How Climatic Seasons of the Amazon Biome Affect the Aromatic and Bioactive Profiles of Fermented and Dried Cocoa Beans?

In addition to the vast diversity of fauna and flora, the Brazilian Amazon has different climatic periods characterized by periods with greater and lesser rainfall. The main objective of this research was to verify the influence of climatic seasons in the Brazilian Amazon (northeast of Pará state) concerning the aromatic and bioactive profiles of fermented and dried cocoa seeds. About 200 kg of seeds was fermented using specific protocols of local producers. Physicochemical analyzes (total titratable acidity, pH, total phenolic compounds, quantification of monomeric phenolics and methylxanthines) and volatile compounds by GC-MS were carried out. We observed that: in the summer, the highest levels of aldehydes were identified, such as benzaldehyde (6.34%) and phenylacetaldehyde (36.73%), related to the fermented cocoa and honey aromas, respectively; and a total of 27.89% of this same class was identified during winter. There were significant differences (p ≤ 0.05, Tukey test) in the profile of bioactive compounds (catechin, epicatechin, caffeine, and theobromine), being higher in fermented almonds in winter. This study indicates that the climatic seasons in the Amazon affect the aromatic and bioactive profiles and could produce a new identity standard (summer and winter Amazon) for the cocoa almonds and their products.     

Replicate periodic windows in the parameter space of driven oscillators

In the bi-dimensional parameter space of driven oscillators, shrimp-shaped periodic windows are immersed in chaotic regions. For two of these oscillators, namely, Duffing and Josephson junction, we show that a weak harmonic perturbation replicates these periodic windows giving rise to parameter regions correspondent to periodic orbits. The new windows are composed of parameters whose periodic orbits have the same periodicity and pattern of stable and unstable periodic orbits already existent for the unperturbed oscillator. Moreover, these unstable periodic orbits are embedded in chaotic attractors in phase space regions where the new stable orbits are identified. Thus, the observed periodic window replication is an effective oscillator control process, once chaotic orbits are replaced by regular ones.     

Investigation of the long-term stability of arc-induced gratings heat treated at high temperatures

A long-period grating written in the SMF-28 fibre was heat treated at 1000 °C for 15 days. The spectrum of the grating shifted to longer wavelengths and the resonances depth decreased as a result of structural relaxation. The background loss increased considerably for times longer than 200 h, and this loss is caused by devitrification of the fibre.     

Mucuna pruriens Administration Minimizes Neuroinflammation and Shows Anxiolytic,Antidepressant and Slimming Effects in Obese Rats

This study evaluated the effect of Mucuna pruriens (MP) administration on neuroinflammation and behavioral and murinometric parameters in obese rats. Proximate composition, oligosaccharide and phenolic compound profile of MP were determined. Wistar adult male rats were randomized into healthy (HG) and obese group (OG). The HG consumed a control chow diet while OG consumed a cafeteria diet for eight weeks. Then, they were subdivided into: Healthy (HG); Healthy with MP administration (HGMP); Obese (OG); Obese with MP administration (OGMP), with the consumption of the respective diets remaining for another eight weeks, in addition to gavage with MP extract to supplemented groups (750 mg/kg weight). MP presented a composition rich in proteins and phenolic compounds, especially catechin, in addition to 1-kestose and levodopa. Supplementation reduced food intake, body weight, and thoracic and abdominal circumferences in obese rats. MP showed anxiolytic and antidepressant effects and reduced morphological damage and expression of interleukin 6 in the hippocampus of obese rats. MP treatment showed satietogenic, slimming, anxiolytic and antidepressant effects, besides to minimizing hippocampal neuroinflammation in obese rats. Our results demonstrated the potential anti-obesity of MP which are probably related to the high content of bioactive compounds present in this plant extract.     

Si-based erbium-doped light-emitting devices

We report on the fabrication and performance of Si-based light sources. The devices consist of MOS structures with erbium (Er)-doped silicon rich oxide (SRO) film as gate dielectric. The devices exhibit electroluminescence (EL) at 1.54 μm at room temperature with a 0.2% external quantum efficiency. These devices show a high stability due to the silicon excess in the film. The Er-doped SRO films have been introduced in a Si/SiO₂ Fabry-Perot Microcavity in order to increase the spontaneous emission rate, the extraction efficiency and the spectral purity at the resonant wavelength. The active medium in the cavity has been electrically pumped and the conduction mechanisms have been analyzed. The EL spectra have also been acquired and compared with photoluminescence (PL) ones for the same resonant cavity light-emitting device (RCLED). The EL and PL peak intensities of the on-axis emission at the resonant wavelength are over 20 times above that of the similar Er-doped SRO film without a cavity. The Si-based RCLEDs exhibit different quality factors, ranging from 60 to 170. The spectra shape and intensity have been correlated with the quality factor. A high directionality of the emitted light, due to the presence of the resonant cavity, has also been observed: the overall luminescence is confined within 10° cone from the sample normal.     

Si-based materials and devices for light emission in silicon

We report on the fabrication and performances of extremely efficient Si-based light sources. The devices consist of MOS structures with erbium (Er) implanted in the thin gate oxide. The devices exhibit strong 1.54 μm electroluminescence (EL) at 300 K with a 10% external quantum efficiency, comparable to that of standard light-emitting diodes using III–V semiconductors. Er excitation is caused by hot electrons impact and oxide wearout limits the reliability of the devices. Much more stable light-emitting MOS devices have been fabricated using Er-doped silicon rich oxide (SRO) films as gate dielectric. These devices show a high stability, with an external quantum efficiency reduced to 1%. In these devices, Er pumping occurs by energy transfer from the Si nanostructures to the rare-earth ions. Finally, we have also fabricated MOS structures with Tb- and Yb-doped SiO₂ which show room temperature EL at 540 nm (Tb) and 980 nm (Yb) with an external quantum efficiency of a 10% and 0.1%, respectively.     

How many elements are needed to generate a finite group with good probability?

We prove that for any real number 0<α<1, there exists a constantc _α such that the probability of generating a finite groupG with [d(G)+c _α log log |G| log log log |G|] elements is at least α.     

Hamiltonian quantization of the non-anomalous generalized Schwinger model

We quantize a generalized version of the Schwinger model, where the two chiral sectors couples with different strengths to theU(1) gauge field. Starting from a theory which includes a generalized Wess-Zumino term, we obtain the equal time commutation relation for physical fields, both the singular and non-singular cases are considered. The photon propagators are also computed in their gauge dependent and invariant versions.     

Electronic structure calculation of V2+O2 complexes in silicon

The self-consistent field multiple-scattering Xα molecular cluster model is applied to calculate the electronic states of a divacancy plus two oxygen complex in silicon. The calculations were carried out for the undistorted configuration of the defect. The obtained results, which are in fairly good agreement with EPR measurements, confirm the main features of the accepted microscopic model for the Si - P2 center.     

The electrocopolymerization of styrene with vinyl acetate in an organic solvent

Copolymers of styrene and vinyl acetate were synthesized electrochemically. The reaction system was composed of methylene chloride as the solvent, and a quaternary ammonium salt as the electrolyte. The reactions were run in a divided cell and the influence of current strength, reaction time, and temperature on the yield, molecular weight, and chemical composition of the resulting copolymers was investigated. It was found that the polymer chains were composed mainly of styrene units.