Evaluation of atmospheric galvanic aluminum corrosion in electrical transmission towers at different sites in the Valparaíso region,Chile. Wire-on-Bolt Test (CLIMAT)

This study evaluates environmental aggressiveness and atmospheric galvanic corrosivity categories in Chile (Classification of Industrial and Marine ATmospheres test) by installing bolts in electrical transmission towers in the Valparaiso region across four exposure sites: Playa Ancha, San Sebastián, Las Vegas, and San Felipe. Classifications of marine corrosion index (MCI), industrial corrosion index (ICI), and atmospheric corrosion index (ACI) used different galvanic couples: aluminum/steel for MCI, aluminum/copper for ICI, and aluminum/polyethylene for ACI. Corrosion indices varied by season (summer, autumn, winter, and spring), for which couples were exchanged every 3 months. Intraseason variation depended mainly on the meteorochemical variables of the zone, the Cl⁻/SO₂ ratio, and the presence of general and pitting corrosion in the aluminum. The results indicate that, regardless of environmental condition, the aluminum in Al/steel (MCI) and Al/copper (ICI) couples presented a higher corrosion rate than when not forming a galvanic couple (ACI). Moreover, under higher environmental chloride, these differences increase. The Playa Ancha station presented the highest ACI.     

Unraveling Protein Interactions between the Temperate Virus Bam35 and Its Bacillus Host Using an Integrative Yeast Two Hybrid–High Throughput Sequencing Approach

Bacillus virus Bam35 is the model Betatectivirus and member of the family Tectiviridae, which is composed of tailless, icosahedral, and membrane-containing bacteriophages. Interest in these viruses has greatly increased in recent years as they are thought to be an evolutionary link between diverse groups of prokaryotic and eukaryotic viruses. Additionally, betatectiviruses infect bacteria of the Bacillus cereus group, which are known for their applications in industry and notorious since it contains many pathogens. Here, we present the first protein–protein interactions (PPIs) network for a tectivirus–host system by studying the Bam35–Bacillus thuringiensis model using a novel approach that integrates the traditional yeast two-hybrid system and high-throughput sequencing (Y2H-HTS). We generated and thoroughly analyzed a genomic library of Bam35′s host B. thuringiensis HER1410 and screened interactions with all the viral proteins using different combinations of bait–prey couples. Initial analysis of the raw data enabled the identification of over 4000 candidate interactions, which were sequentially filtered to produce 182 high-confidence interactions that were defined as part of the core virus–host interactome. Overall, host metabolism proteins and peptidases were particularly enriched within the detected interactions, distinguishing this host–phage system from the other reported host–phage PPIs. Our approach also suggested biological roles for several Bam35 proteins of unknown function, including the membrane structural protein P25, which may be a viral hub with a role in host membrane modification during viral particle morphogenesis. This work resulted in a better understanding of the Bam35–B. thuringiensis interaction at the molecular level and holds great potential for the generalization of the Y2H-HTS approach for other virus–host models.     

Development and characterisation of microporous biomimetic scaffolds loaded with magnetic nanoparticles as bone repairing material

Fine-tuning of the scaffolds structural features for bone tissue engineering can be an efficient approach to regulate the specific response of the osteoblasts. Here, we loaded magnetic nanoparticles aka superparamagnetic iron oxide nanoparticles (SPIONs) into 3D composite scaffolds based on biological macromolecules (chitosan, collagen, hyaluronic acid) and calcium phosphates for potential applications in bone regeneration, using a biomimetic approach. We assessed the effects of organic (chitosan/collagen/hyaluronic acid) and inorganic (calcium phosphates, SPIONs) phase over the final features of the magnetic scaffolds (MS). Mechanical properties, magnetic susceptibility and biological fluids retention are strongly dependent on the final composition of MS and within the recommended range for application in bone regeneration. The MS architecture/pore size can be made bespoken through changes of the final organic/inorganic ratio. The scaffolds undertake mild degradation as the presence of inorganic components hinders the enzyme catalytic activity. In vitro studies indicated that osteoblasts (SaOS-2) on MS9 had similar cell behaviour activity in comparison with the TCP control. In vivo data showed an evident development of integration and resorption of the MS composites with low inflammation activity. Current findings suggest that the combination of SPIONs into 3D composite scaffolds can be a promising toolkit for bone regeneration.     

Composites of poly(vinyl acetate) filled with calcium carbonate: Microscopy,diffractometry and thermophysical properties

Calcium carbonate (CaCO₃) is used as filler in poly(vinyl acetate)(PVAc) composites to enhance the mechanical properties. The filler is often commercially surface treated with stearic acid to optimize the interfacial bonding and wetting. The effects of the interface on properties were studied using scanning electron microscopy (SEM) of films with initial and deformed morphologies. Plasticizing additives cause a significant change in the appearance of the films and a reduction in the glass transition temperature of the matrix from 40°C to ≈ 18°C, which was not altered by further addition of the filler. A PVAc composite fracture surface shows the particles adhering well to the matrix, suggesting good adhesion and reinforcement. The SEM study is complemented by WAXD, SEM/X-SEM, XPS, and thermal analysis.     

VIS absorption spectrophotometry of disperse dyes

In the investigations of the dyeing processes, the low solubility of disperse dyes in water represents a practical problem for the determination of dye concentration in dyebaths and waste waters. Therefore the use of an organic solvent which, dissolves disperse dyes, is recommended in visible spectrophotometry of disperse dyes. Three organic solvents (ethanol, N,N-dimethylformamide, acetone) and two disperse dyes, the disazo dye C.I. Disperse Orange 29 and the anthraquinone dye C.I. Disperse Blue 56, were used for spectroscopic analysis in this present work. The absorbance of aqueous dye dispersions and various organic solvent dye solutions was measured to evaluate the effect of the solvent on the shape and intensity of the absorption spectra and on the wavelength shift of maximum absorption. The validity of Beer–Lambert’s law in each system was ascertained. A suggestion is made how VIS absorption spectrophotometry can be used to determine the dye concentration in disperse dyebaths. The addition of organic solvent to the dyebath leads to dye dissolution, and the Beer-Lambert’s law is then fulfilled. The optimum ratio between the dyebath dispersion and the organic solvents for the dyes investigated is also determined.     

A single-phase model for liquid-feed DMFCs with non-Tafel kinetics

An isothermal single-phase 3D/1D model for liquid-feed direct methanol fuel cells (DMFC) is presented. Three-dimensional (3D) mass, momentum and species transport in the anode channels and gas diffusion layer is modeled using a commercial, finite-volume based, computational fluid dynamics (CFD) software complemented with user supplied subroutines. The 3D model is locally coupled to a one-dimensional (1D) model accounting for the electrochemical reactions in both the anode and the cathode, which provides a physically sound boundary condition for the velocity and methanol concentration fields at the anode gas diffusion layer/catalyst interface. The 1D model – comprising the membrane–electrode assembly, cathode gas diffusion layer, and cathode channel – assumes non-Tafel kinetics to describe the complex kinetics of the multi-step methanol oxidation reaction at the anode, and accounts for the mixed potential associated with methanol crossover, induced both by diffusion and electro-osmotic drag. Polarization curves computed for various methanol feed concentrations, temperatures, and methanol feed velocities show good agreement with recent experimental results. The spatial distribution of methanol in the anode channels, together with the distributions of current density, methanol crossover and fuel utilization at the anode catalyst layer, are also presented for different opperating conditions.     

Production of isobutylene from acetone over micro–mesoporous catalysts

The production of isobutylene from acetone over micro–mesoporous catalysts with different mesopore contents, which have been prepared using hydrothermal recrystallization of mordenite (MOR) zeolite modified with cesium acetate by incipient wetness impregnation, has been studied. It has been shown that cesium is inserted into the cation positions during the modification, at the same time the number of Brønsted acid sites in the samples decreased. It has been found that an increase in the content of mesopores in the catalyst leads to an increase in the initial rates of acetone conversion and isobutylene formation as a result of removing diffusion limitations. Brønsted acid sites have been shown to be preferable for the selective production of isobutylene from acetone. Micro–mesoporous materials operate more stably as compared to microporous materials.     

Improving the control of food production in catering establishments with particular reference to the safety of salads

Food production in four school kitchens was checked in order to improve food safety by establishing a self-regulated control system based on good manufacturing practices (GMPs) and as an introduction to hazard analysis and critical control points (HACCP). A form, which referred to different aspects such as the cleanliness of the installations, personnel hygiene and the prevention of cross-contamination, was used to obtain the necessary data. Furthermore, foods thought to be of high risk were periodically collected for microbiological analysis. Samples for microbiological examination were taken from cutting boards, tables, machines, knives and ingredients (on-line sampling). We used the results as a basis to train foodhandlers to improve the safety of salad preparation, in accordance with GMPs, observing that hygiene improvement depended on chlorine levels in the rinsing water. We also designed several controls for raw materials, cold storage, freezers and available chlorine levels in water. At the end of the study period, we observed a decrease in microbial populations of examined samples, which indicated that the knowledge of hygiene practices on the part of foodhandlers represents a critical control point, as defined by the EC Directive 93/43/EEC on Hygiene of Food Stuffs.