Synergy between high-pressure, temperature and ascorbic acid on the inactivation of Bacillus cereus

B. cereus strain (CECF 148) was used as a model system in the study of the behaviour of bacillus under high pressure, at temperatures over and below 0 °C and with ascorbic acid added to the culture. Three different assays were carried out in the present experiment. The first assay was performed to observe how B. cereus reacted to pressure shift freezing (PSF) treatment at different subzero temperatures (−8, −12, −20 and −17 °C) and pressures (120, 150, 210 and 350 MPa) in their vegetative form. In the second assay, we observed how different concentrations of ascorbic acid (1, 2, 5 and 20 mM) added to the growing brought decreased B. cereus on its vegetative form. Finally, we tried to inactivate the vegetative and spore form of B. cereus under pressure of 210 MPa at room (20 °C) (HP) and at subzero (−20 °C) (PSF) temperatures, in presence of ascorbic acid (20 mM), added to the growing culture (TSB). The results confirmed that pressures of 210 and 350 MPa at low temperatures (−20 and −17 °C) in the PSF treatment were not enough to inactivate bacillus and only about 10% of B. cereus at the assayed conditions (350 MPa at −17 °C) lost its growth capacity. The presence of ascorbic acid reduced the amount of B. cereus. The initial amount of B. cereus in the vegetative form was 10⁸ to 10⁹ cfu/mL. After HP (210 MPa at 20 °C) and PSF (210 MPa at −20 °C) treatments, the amount of B. cereus decreased by 4 and 2 logarithmic units, respectively. However, in both treatments, the presence of ascorbic acid (20 mM concentration) reduced the B. cereus growth capacity in about 5 logarithmic units. The presence of ascorbic acid in the spore form decreased the amount of B. cereus only by 2 logarithmic units, but without the antioxidant, the values remained close to control. The present research is a contribution to elicit the safety standards of food treated by high pressure.     

Esterification of Free Fatty Acids Using Layered Carboxylates and Hydroxide Salts as Catalysts

Layered lanthanum and copper(II) laurates were tested as catalysts for methanolic esterification of lauric acid (C₁₂). Factorial design evidenced a positive effect of reaction temperature and amount of catalyst on ester conversion, while the acid:alcohol molar ratio (MR) had a negative effect. With lanthanum laurate, 90.5% conversion was reached at 140???C with 10% catalyst and MR of 6:1. Although the highest conversion with copper(II) laurate converted 81.5% under the same conditions, results were better with a lower amount of catalyst (78% ester at 140???C with 2% catalyst and MR of 6:1). A calcium hydroxide succinate was also investigated showing better catalytic performance than the well-known CaO, under mild reaction conditions (120???C with 1% catalyst and MR of 3:1). Although layered carboxylates can be successively reused, the layered calcium hydroxide salt transformed into inactive CaCO₃ in the second reuse reaction.     

Preparation and characterization of acrylic acid/itaconic acid hydrogel coatings containing silver nanoparticles

Hydrogel silver nanocomposites have been used in applications with excellent antibacterial performance. Acrylic acid (AA)/itaconic acid (IA) hydrogels silver nanocomposites were prepared and applied as a coating on a textile substrate. Hydrogel matrices were synthesized first by the polymerization of an AA/IA aqueous (80/20 v/v) solution and mixed with 2‐2‐azobis(2‐methylpropionamide) diclorohydrate and N,N′‐methylene bisacrylamide until the hydrogel was formed. Silver nanoparticles were generated throughout the hydrogel networks with an in situ method via the incorporation of the silver ions and subsequent reduction with sodium borohydride. Cotton (C) and cotton/polyester (CP) textile fibers were then coated with these hydrogel silver nanocomposites. The influence of these nanocomposite hydrogels on the properties of the textile fiber were investigated by infrared spectroscopy (attenuated total reflectance), scanning electron microscopy, energy‐dispersive X‐ray spectroscopy, and antibacterial tests against Pseudomona aeruginosa and Staphylococcus aureus. The better conditions, in which no serious aggregation of the silver nanoparticles occurred, were determined. It was proven that the textiles coated with hydrogels containing nanosilver had an excellent antibacterial abilities. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 2713–2721, 2013     

Amino acids and biogenic amines in red varietal wines: the role of grape variety, malolactic fermentation and vintage

This work studies for the first time the amino acid and biogenic amine composition of Rioja red wines made with the red minority varieties Vitis vinífera cv. Monastel and Maturana Tinta de Navarrete, using Tempranillo as a reference variety. The role of malolactic fermentation and vintage on these compounds was also analysed, and discriminate analyses were applied to achieve a possible differentiation of the wines. Amino acid composition allowed a differentiation of wines according to grape variety. Monastel was characterised by the highest value in β-alanine and Maturana Tinta de Navarrete by its highest value in OH-proline. However, biogenic amines were no able to classify varietal wines. The malolactic fermentation had significant changes on the amino acid and biogenic amine content, and allowed distinguishing wines that underwent this process from wines without malolactic fermentation. No correlation was found between total amino acids and total biogenic amines after malolactic fermentation, suggesting that a higher initial concentration of amino acids in the medium did no affect the concentration of biogenic amines after malolactic fermentation. Vintage influenced the amino acid and biogenic amine pattern, obtaining a clear separation of wines by vintages. Monastel and Maturana Tinta de Navarrete wines showed a minor varietal character and were more influenced by the climatic conditions of each vintage than Tempranillo wines. All the wines showed histamine levels below the human physiological threshold and implemented regulations.     

Differential Expression of Proteins in an Atypical Presentation of Autoimmune Lymphoproliferative Syndrome

Autoimmune lymphoproliferative syndrome (ALPS) is a rare disease defined as a defect in the lymphocyte apoptotic pathway. Currently, the diagnosis of ALPS is based on clinical aspects, defective lymphocyte apoptosis and mutations in Fas, FasL and Casp 10 genes. Despite this, ALPS has been misdiagnosed. The aim of this work was to go one step further in the knowledge of the disease, through a molecular and proteomic analysis of peripheral blood mononuclear cells (PBMCs) from two children, a 13-year-old girl and a 6-year-old boy, called patient 1 and patient 2, respectively, with clinical data supporting the diagnosis of ALPS. Fas, FasL and Casp10 genes from both patients were sequenced, and a sample of the total proteins from patient 1 was analyzed by label-free proteomics. Pathway analysis of deregulated proteins from PBMCs was performed on the STRING and PANTHER bioinformatics databases. A mutation resulting in an in-frame premature stop codon and protein truncation was detected in the Fas gene from patient 2. From patient 1, the proteomic analysis showed differences in the level of expression of proteins involved in, among other processes, cell cycle, regulation of cell cycle arrest and immune response. Noticeably, the most down-regulated protein is an important regulator of the cell cycle process. This could be an explanation of the disease in patient 1.     

Improving thermo-responsive hydrogel films by gamma rays and loading of Cu and Ag nanoparticles

This paper presents two modified copolymeric hydrogel films with thermo-responsiveness. The final films are hydrogels containing N-isopropylacrylamide, N-N-dimethylacrylamide, methyl methacrylate, and ethoxyethyl methacrylate. The incorporation of Ag and Cu in the smart hydrogel films endowed them with specific properties that could be useful in developing biological sensors, smart membranes, or flexible electronic components, which are proper for design and improvement on technology and biomedical applications. The films were synthesized in solution by gamma radiation at a dose rate of 10 kGy h⁻¹, and an absorbed dose of 50 kGy. The characterization was realized by different spectroscopic and microscopic techniques as FTIR-ATR, atomic force microscopy, SEM–EDX, TGA, and DSC. The hydrogel films were grafted with glycidyl methacrylate showing high resistance, biocompatibility, adequate adaptability, flexibility, in addition to the capacity of metal doping with silver and copper.     

Chiral Photodetector Based on GaAsN

The detection of light helicity is key for various applications, from drug production to optical communications. However, the light helicity direct measurement is inherently impossible with conventional photodetectors based on III–V or IV–VI non-chiral semiconductors. The prior polarization analysis by often moving optical elements is necessary before light is sent to the detector. A method is here presented to effectively give the conventional dilute nitride GaAs-based semiconductor epilayer a chiral photoconductivity. The detection scheme relies on the giant spin-dependent recombination of conduction electrons and the accompanying spin polarization of the engineered defects to control the conduction band. As the conduction electron spin polarization is, in turn, intimately linked to the excitation light polarization, the light polarization state and intensity can be determined by a simple conductivity measurement. This approach, removing the need for any optical elements in front of a non-chiral detector, could offer easier integration and miniaturization. This new chiral photodetector could potentially operate in a spectral range from the visible to the infra-red using (InGaAl)AsN alloys or ion-implanted nitrogen-free III–V compounds.     

An Internet of Things Platform for Air Station Remote Sensing and Smart Monitoring

Air pollution is currently receiving more attention by international governments and organizations. Nevertheless, current systems for air quality monitoring lack essential requirements which are key in order to be effective concerning users’ access to the information and efficient regarding real-time monitoring and notification. This paper presents an Internet of Things platform for air station remote sensing and smart monitoring that combines Big Data and Cloud Computing paradigms to process and correlate air pollutant concentrations coming from multiple remote stations, as well as to trigger automatic and personalized alerts when a health risk for their particular context is detected. This platform has been tested by analyzing the results of observing Andalusian, South of Spain, sensor network during a long period of time. The results show that this novel solution can help to reduce the impact of air pollution on human health since citizens are alerted in real time.     

Sulfuric acid treatment of ground tire rubber and its effect on the mechanical and thermal properties of polypropylene composites

Ground tire rubber (GTR) was modified by sulfuric acid in order to improve its compatibility with and reinforcement of a polypropylene (PP) matrix. Polymer composites PP/GTR were prepared by melt mixing at different concentrations, with a maximum of 50 wt % of GTR. Studies by Fourier transform infrared spectroscopy (FTIR), surface specific area by BET (Brunauer, Emmett, and Teller), and scanning electron microscopy were used to characterize the untreated GTR and treated GTR, while the mechanical and thermal properties of the PP/GTR composites were assessed to understand how the surface treatment of GTR affected the mechanical and thermal properties of the composite PP/GTR. FTIR revealed the presence of sulfonic groups on the surface of sulfuric acid–treated GTR, and BET analyses showed an increase of about 625% in the specific surface area as a result of the high porosity produced by the treatment. In all composites containing treated GTR, a higher Young's modulus was obtained than for composites containing untreated GTR. Particularly, an increase of about 275% in the Young's modulus was obtained in composites with treated GTR (40 wt %) against that containing untreated GTR. However, a more significant reduction of the elongation at break was observed in composites containing treated GTR than in those containing untreated GTR. Also, an increase of the crystallization temperature of PP as a function of GTR was observed by differential scanning calorimetry, but the crystallinity of the composites was reduced by the addition of both untreated and treated GTR. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 44858.     

Ebony (Phitecellobium flexicaule Benth) and proteins fractionation,solubilization, characterization and production of an isolate

Different combinations of pHs (2 to 12) and temperatures (25, 30 and 35 degrees C) were tested to obtain a protein isolate from ebony (Pithecellobium flexicaule, Benth) seeds. Seed proteins contained 54.6% albumins, 32% globulins, 5.7% glutelins and 1.3% prolamins. The isoelectric points for albumins, globulins and glutelins were in the pH range of 2.3-2.7. The average molecular weight of albumins ranged from 92 to 100 kDa and for the four globulin subunits in the range of 28.4 to 57.3 kDa. For isolate production, proteins were sequentially extracted with distilled water and a 5% NaCl solution. The resulting supernatants were mixed. The best extraction was achieved at pH 11 and 25 degrees C. 45.6% of the total seed protein was precipitated at pH 2.6 yielding an isolate with 90% protein (N x 6.25). The isolate contained high quantities of lysine, leucine, threonine and phenylalanine but were low in sulfur containing amino acids methionine and cysteine. The extraction process reduced tannins, phytates and trypsin inhibitor in 53, 70 and 70%, respectively. In vivo protein digestibility of the protein isolate was 85.4% and the corrected digestibility essential amino acid score was of 44% due to the lack of sulfur containing amino acids. In order to upgrade the protein quality of ebony isolate it is recommend to supplement with methionine or sulfur containing rich foods.