Analyticity and Smoothing Effect for the Coupled System of Equations of Korteweg-de Vries Type with a Single Point Singularity

Using Bourgain spaces and the generator of dilation P=3t ? _t +x ? _x , which almost commutes with the linear Korteweg-de Vries operator, we show that a solution of the initial value problem associated for the coupled system of equations of Korteweg-de Vries type which appears as a model to describe the strong interaction of weakly nonlinear long waves, has an analyticity in time and a smoothing effect up to real analyticity if the initial data only have a single point singularity at x=0.     

Optimization of <Emphasis Type="Italic">α</Emphasis>-Terpineol Production by the Biotransformation of <Emphasis Type="Italic">R</Emphasis>-(+)-Limonene and (−)-β-Pinene

The main objective of this work is to present the optimization of the biotransformation of R-(+)-limonene and (−)-β-pinene aiming at the production of α-terpineol by strains of fungal and yeasts previously isolated by our research group using the methodology of experimental design. New optimized experimental data on α-terpineol production by the biotransformation of R-(+)-limonene and (−)-β-pinene using newly isolated microorganisms are reported in this work. Conversion of about 1,700 mg/L was achieved when R-(+)-limonene was used as substrate and the newly isolated strain 05.01.35 as microorganism at the central point of the experimental design, corresponding to a substrate concentration of 1.75%, mass of inoculum of 2 g, and substrate to ethanol volume ratio of 1:1. The same experimental condition led to higher conversions when (−)-β-pinene was used as substrates and the strains coded as 04.05.08 and 01.04.03 as microorganism. Here, conversions of about 770 mg/L were achieved.     

Auslander–Buchweitz Approximation Theory for Triangulated Categories

We introduce and develop an analogous of the Auslander–Buchweitz approximation theory (see Auslander and Buchweitz, Societe Mathematique de France 38:5–37, 1989) in the context of triangulated categories, by using a version of relative homology in this setting. We also prove several results concerning relative homological algebra in a triangulated category $\mathcal{T},$ which are based on the behavior of certain subcategories under finiteness of resolutions and vanishing of Hom-spaces. For example: we establish the existence of preenvelopes (and precovers) in certain triangulated subcategories of $\mathcal{T}.$ The results resemble various constructions and results of Auslander and Buchweitz, and are concentrated in exploring the structure of a triangulated category $\mathcal{T}$ equipped with a pair $(\mathcal{X},\omega),$ where $\mathcal{X}$ is closed under extensions and ω is a weak-cogenerator in $\mathcal{X},$ usually under additional conditions. This reduces, among other things, to the existence of distinguished triangles enjoying special properties, and the behavior of (suitably defined) (co)resolutions, projective or injective dimension of objects of $\mathcal{T}$ and the formation of orthogonal subcategories. Finally, some relationships with the Rouquier’s dimension in triangulated categories is discussed.     

The Three‐Component Biginelli Reaction: A Combined Experimental and Theoretical Mechanistic Investigation

Biginelli reactions have been monitored by direct infusion electrospray ionization mass spectrometry (ESI‐MS) and key cationic intermediates involved in this three‐component reaction have been intercepted and further characterized by tandem MS experiments (ESI‐MS/MS). Density functional theory calculations were also used to investigate the feasibility of the major competing mechanisms proposed for the Biginelli reaction. The experimental and theoretical results were found to corroborate the iminium mechanism proposed by Folkers and Johnson, whereas no intermediates directly associated with either the more energy demanding Knoevenagel or enamine mechanisms could be intercepted.     

Synthesis of Ammonium-Based Ionic Liquids for the Extraction Process of a Natural Pigment (Betanin)

The use of new synthesized ammonium-based ionic liquids was explored as an alternative to the current process implemented in the betanin extraction from red beet juice, resulting in high yields: 70% and 82%. Betanin is a vegetal pigment that has been applied to a large variety of products in the food industry, which is important, for it can work as a substitute for the red synthetic dyes used nowadays. Additionally, the use of the kosmotropic salt sodium acetate was explored in order to separate the complex formed by the ionic liquid and pigment of interest in a process that combined two techniques: ATPS (aqueous two-phase system) and SOES (salting-out extraction system). The results reveal that the studied techniques could work as a novel process for the extraction of betanin from red beet juice employing ionic liquids, which have not been tested for this purpose in other research.     

Physicochemical,Structural, Thermal and Rheological Properties of Flour and Starch Isolated from Avocado Seeds of Landrace and Hass Cultivars

The objective of this study was to obtain and characterize flours and starches from the avocado seeds of Hass and landrace cultivars. The morphological, physical-chemical, structural, thermal and rheological characteristics were evaluated. The flour yield of the Hass and landrace cultivars was 41.56 to 46.86% (w/w), while for starch, it was 35.47 to 39.57% (w/w) (cv. Hass and landrace, respectively). Scanning electron microscopy (SEM) revealed the presence of oval starch granules and other particles in flour, in contrast to flours, starches showed lower ash, proteins and lipids content. However, the amylose content was higher in starches (42.25–48.2%). Flours showed a higher gelatinization temperature (T_p = 73.17–73.62 °C), and their starches presented greater gelatinization enthalpy (∆H_gel = 11.82–13.43 J/g). All samples showed a B-type diffraction pattern, and the crystallinity was higher in the flours. The rheological analysis (flow curves and viscoelastic tests) evidenced a pseudoplastic (n = 0.28–0.36) behavior in all samples analyzed, but the consistency index (k) was higher in starches. In general, the flours and starches from avocado seeds presented interesting proximal, thermal and functional properties for possible application in food systems, and these findings could contribute to the revaluation of this by-product.     

Synthesis and characterization of RuS2 nanostructures

Small naked ruthenium sulfide nanoparticles (NPs) with narrow size distribution (2.5 +/- 0.4 nm of diameter) were synthesized in DMSO colloidal dispersions, under mild reaction conditions and using commercial RuCl3 as precursor. To test the chemical reactivity with soft and hard bases, fresh presynthesized RuS2 colloids were mixed with triethylamine (N(Et)3) and ammonium tetrathiomolybdate ((NH4)2MoS4) dimethyl sulfoxide solutions. Naked N(Et)3 and [MoS4](2-)-capped RuS2 nanoparticle colloids were characterized using UV-visible electronic absorption and emission spectroscopies and high-resolution transmission electron microscopy (HR-TEM). It has also been shown that capped RuS2-[MoS4]2- nanoparticles yield MoO3 crystalline matrix by means of HR-TEM experiments. The emission spectra of RuS2 and N(Et)3-RuS2 dispersions show that both nanosized materials have strong fluorescence. The existence of the ruthenium precursor species in solution was established by cyclic voltammetry. Moreover, naked RuS2 NPs were mixed with a chemical mixture with composition similar to gasoline (dibenzothiophene (Bz2S, 400 ppm), hexane, and toluene (55:45% v/v)). The reaction mixture consisted of two phases; in the polar phase, we found evidences of a strong interaction of Bz2S and toluene with the naked RuS2 NPs. We have also obtained self-organized thin films of capped N(Et)3- and RuS2-[MoS4]2- nanoparticles. In both cases, the shape and thickness of the resulting thin films were controlled by a dynamic vacuum procedure. The thin films have been characterized by atomic force microscopy, scanning electron microscopy, HR-TEM, energy dispersion spectroscopy, X-ray diffraction, and absorbance and fluorescence spectroscopies.