Use of Microwave Maceration in Red Winemaking: Effect on Fermentation and Chemical Composition of Red Wines

The objective of this study was to evaluate the effect of microwave treatment of crushed grapes on the yeast population of the must and on the development of alcoholic fermentation, as well as on the extraction of different compounds from the grapes such as polysaccharides and amino acids that can affect the organoleptic quality and stability of the wine. This study demonstrated for the first time the effect of the microwave treatment of grapes on native yeast species and their diversity, producing an increase in fermentation kinetics and a decrease in the lag phase. The microwave treatment produced a positive effect on the extraction of amino acids and polysaccharides from the grapes, resulting in significantly higher amounts of the main amino acids of the must and some major volatile compounds in the treated samples. The polysaccharides most affected by the microwave treatment were the PRAGs, the main polysaccharides liberated from grapes during the maceration.     

Ultrasound-assisted microencapsulation of jackfruit extract in eco-friendly powder particles: characterization and antiproliferative activity

The aim of the article was to develop stable and safe eco-friendly microcapsules and evaluate their physicochemical properties and their efficiency to protect a jackfruit extract. Eco-friendly microcapsules were produced by ultrasound and spray drying using only three safe ingredients: sucrose ester (SE), miglyol and maltodextrin (DE = 10). Some physicochemical properties, particle morphology, FT-IR, differential scanning calorimetry and antiproliferative activity were determined for microcapsules loaded or not with the jackfuit extract. The results revealed that the encapsulation process by spray drying produced stable microcapsules, with adequate physicochemical and fluid properties for a powder product. The cell viability on the proliferation of M12.C3.F6 cell line was not affected by powder microcapsules without jackfruit extract, indicating that capsules are not toxic for these cells. However, microcapsules with jackfruit extract (100 μg/ml) were able to inhibit significantly the proliferation of M12.C3.F6 cells. These microcapsules can be used for the protection of different compounds sensitive to light, oxygen and/or heat and displaying a very low aqueous solubility.     

Drug release system of ibuprofen in PCL-microspheres

Today, the technology of microencapsulation of active principles is on top of biomedical advances, because through it we can solve many of the problems caused by current methods of taking medication. Active principle microencapsulation not only solves the problems of drug intake but also controls its dosage. In this study was carried out the development of a protocol for the microencapsulation of ibuprofen by solvent evaporation method. A subsequent application of those microencapsulates to biofunctional textile substrates (cotton, polyamide, acrylic, and polyester) using a finishing process, and finally a study of the release of active principle in two different media (deionized water and physiological serum) has been carried out using samples of the treated fabrics that were submerged into a thermostatized vessel at semi-infinite bath conditions. The determination of active principles released to the bath was determined by a UV spectrophotometer. These experimental results have been analyzed and evaluated, and have therefore allowed to define a controlled drug release system by Fickian diffusion in different media.     

Thermal photon production in a strongly coupled anisotropic plasma

Journal of High Energy Physics - For the homogeneous configuration given by the long string limit of the folded string with a spin in AdS 3 and a spin and a winding number in S 1, we solve the...     

Poly(lactic acid) composites with poly(lactic acid)‐modified carbon nanotubes

This work reports the study of the effect of chemical functionalization of carbon nanotubes on their dispersion in poly(lactic acid). The nanotubes were functionalized by the 1,3‐dipolar cycloaddition reaction, generating pyrrolidine groups at the nanotube surface. Further reaction of the pyrrolidine groups with poly(lactic acid) was studied in solution and in the polymer melt. The former involved refluxing the nanotubes in a dimethylformamide/polymer solution; the latter was carried out by direct melt mixing in a microcompounder. The carbon nanotubes collected after each process were characterized by thermogravimetry and by X‐ray photoelectron spectroscopy, showing evidence of polymer bonded to the nanotube surface only when the reaction was carried out in the polymer melt. The composites with polymer modified nanotubes present smaller average agglomerate area and a narrower agglomerate area distribution. In addition, they show improved tensile properties at low CNT concentration and present lower electrical resistivity. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2013, 51, 3740–3750     

Effect of pH and ligand charge state on BACE-1 fragment docking performance

In this work we propose a protocol for estimating the effect of pH on the docking performance to BACE-1, which affords the charge state of the inhibitor as well as the protonation state of all ionisable residues in the protein at a given pH value. To the best of our knowledge, this is the first report of a protocol predicting the BACE-1 ligand docking poses not only at the neutral pH at which most crystallographic structures were obtained, but also at the optimal pH of the enzyme (in the acidic range), at which most of the BACE-1 binding affinity assays are performed. We have applied this protocol to a set of 23 fragment-like BACE-1 ligands that span four orders of magnitude in their binding affinities. The pK _a values of the BACE-1 acidic residues deviate substantially from the estimates for model compounds in solution and display a ligand dependent variability, especially in the case of the catalytic Asp dyad residues. This outcome should have a strong bearing on the design of protocols for docking based BACE-1 screening campaigns. Finally, we were able to find an explanation for the poor docking success rate of some fragments based on the availability of anchoring points, a rationale that could help to improve hit rates in BACE-1 screening campaigns.     

Reaction of 2,3-O-Isopropylidene-D-Glyceraldehyde and Some Dialkyl and Diarylthiomethyl Sulfoxides: Stereochemical Aspects

Abstract

The reaction of 2,3-O-isopropylidene-D-glyceraldehyde with different dialkyl and diarylthiomethyl sulfoxides occurs with a high selectivity and produces the corresponding 1-alkyl(or l-aryl)-sulfynil-l-alkyl(or 1-aryl) thio-3,4-O-isopropylidene-D-tetroses as pure diastereoisomers. We have determined the absolute configuration of the three chiral centers formed in these reactions.     

Phase Transfer Catalyzed Anomeric Nucleophilic Substitutions with D-Xylopyranosyl Halides

Abstract

Anomeric pairs of per-O-acetylated-D-xylopyranosyl halides were individually treated with a wide variety of nucleophiles under mild PTC conditions. Thus, 2,3,4-tri-O-acetyl-α-D-xylopyranosyl bromide 1 provided exclusively the β-D-xylopyranosyl anomers 2-11 in good to excellent yields (65-95%). Alternatively, under the same PTC conditions, 2,3,4-tri-O-acetyl-β-D-xylopyranosyl chloride 13 afforded solely the inverted α-D-anomers 15 (82%) and 16 (67%) upon treatment with thiophenol and sodium azide, respectively. Similarly, 2,3,4,6-tetra-O-acetyl-β-D-glucopyranosyl chloride 19 provided the analogous products 20 (63%) and 21 (31%) upon treatment with thiophenol and sodium azide. In the presence of tetrabutylammonium chloride as PTC catalyst, β-xylopyranosyl chloride 13 was shown to slowly equilibrate to the α-chloride 14. Therefore, care must be taken to avoid PTC catalyst for which counter anions can cause anomerization of the starting glycosyl halides.     

Synthesis of Carbohydrate Derived α-Methylene-γ-lactones by Diasterecseldctive,Low Temperature Reformatsky-Type Reactions

Hexopyranoside- and hexofuranose uloses with either ethyl 2-(branamethyl)acrylate in the presence of laminar Zn/Ag-graphite or ethyl 2-(trimethylsilylinethyl)acrylate/tetra-n-butylanrnonium fluoride undergo stereoselective branching, mainly with formation of spiro α-methylene-γ-lactones.     

Synthesis of Anellated Pyranose Derivatives on the Basis of Levoglucosenone

ABSTRACT

1,6-Anhydro-2-(dicyanomethylene)-2,3-dideoxy-4-S-ethyl-4-thio-β-D-erythro-hexopyranose (1) reacted with tosyl azide or sulfur and triethylamine to furnish the 5-aza-10, 11-dioxatricyclo[6.2.1.0^2,6]undeca-2(6),3-diene-3-carbonitrile 2 and the 10,11-dioxa-5-thiatricyclo[6.2.1.0^2,6]undeca-2(6),3-diene-3-carbonitrile 3, respectively. The reactions of 1 with arylisothiocyanates furnished the 11,12-dioxa-5-thiatricyclo[7.2.1.0^2,7]dodeca-2(7),3-diene-3-carbonitriles 4 and 5. 3 underwent cyclization with triethyl orthoformate and ammonia or hydrazine hydrate to afford the 5,7-diaza-14,15-dioxa-9-thiatetracyclo[10.2.1.0^2,10.0^3.8]pentadecatetra(tri)enes 7 and 8, respectively.