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The nickel removal of the system Ni(II)-NH3-CO2-SO2-H2O was studied by electrocoagulation in a cylindrical reactor with agitation, of 25 L of useful capacity and two pair of Al/Al electrodes. Effluentliquor from the distillation process of the nickelproducer plant in Punta Gorda, Cuba, was processed with nickel concentration from 300 to 652 mg/L, at a current density of 8,3 mA/cm2, 60 °C and pH 8,64 (+/-0,033). An average removal efficiency of 99,65 (+/-0,07) % was obtained, an equilibrium concentration less than 2 mg/L and an adsorption capacity between 3342 and 7264 mg/g. According to the kinetic and equilibrium analysis, it is considered that the process is probably under the control of the resistance of the chemical reaction mechanisms and its autocatalytic contribution. The operation costs for electrical energyand electrode consumption were between 11,122 y 16,022 CUP/kg of removed nickel and the specific energy consumption of 1,709 to 2,342 kW-h/kg of Al. [ABSTRACT FROM AUTHOR]

For the control of Rhipicephalus microplus, cattle tick, pyrethroid compounds are used among others. The study of the mechanisms of resistance to pyrethroids in this tick has shown the presence of mutations in the sodium channel gen, the target site of acaricide. The main objective of the present study was to detect the T2134A polymorphism in the sodium channel gene that has been related to pyrethroid resistance in carriers. To do so, 182 ticks R. microplus were collected in two farms with a history of resistance to this type of acaricide and were subjected to a dip test of females in a cypermethrin solution prepared at the recommended dose for field use, obtaining six susceptible, 92 resistants and 84 moderately resistants. DNA is extracted from all specimens using QIAamp DNA Mini Kit® and processed by conventional PCR using allelespecific primers to amplify a segment of domain IIIS6 of the sodium channel gene. The resulting amplicons were detected by electrophoresis in 2 % agarose gels stained with GelRed® and visualized with ultraviolet light. In the same way, 20 samples were sequenced of the three susceptible phenotypes, moderately resistant and resistant and the resulting sequences were aligned through the Mega 7 program and compared with the sequences stored in the GenBank®. The information of the population of R. Microplus studied did not show the expected mutation but a different mutation in the site 2134. We also observed the substitution of a thymine but by a cytosine, T2134C, which changes to a phenylalanine by a leucine, a difference from the previously identified mutation, that the change from phenylalanine to isoleucine. This shows the presence of a polymorphism that has not been reported in this species of tick and that would generate a new molecular marker of pyrethroid resistance for populations of this mite. [ABSTRACT FROM AUTHOR]

Introduction: Rhipicephalus microplus ticks are hematophagous ectoparasites that economically impact lifestock industry worldwide. Acaricides have been an effective control strategy, but generate resistance to chemical compounds and environmental pollution. An alternative to counteract the chemical adverse effects is the vaccination usage, which is effective, environmentally friendly and unexpensive. However, still anti-tick vaccines present variable efficacy due to possible differences in aminoacid sequences within tick antigens from geografically distinct isolates. The aim of this work was to analyze the variability of two vaccine antigens: BmVDAC (Voltage Dependent Anion Channel) and Subolesin from R. microplus isolates from different states of Mexico. Methods: Two proteins were selected based on its efficacy as protective antigens: BmVDAC and Subolesin. R. microplus ticks was collected from different states of Mexico. Isolation of both DNA and RNA was performed to amplify bmvdac and subolesin respectively. Predicted amino acid sequences were obtained. A BLAST analysis was carried out to confirm the identity within sequences and determine similarity by an alignment using Clustal Omega. Finally, to determine the phylogenetic relationship of each isolate an analysis by MEGAX64 software was performed. Results: For BmVDAC, an average percentage of 99.79% identity and similarity was observed within the different aminoacid sequences. In the isolates from Chiapas, Nayarit, Media Joya, Queretaro, Tamaulipas and Guerrero a similarity and identity percentage of 99.87% was observed. Jalisco, Tabasco and Sinaloa a similarity and identity percentage of 99.56% was presented. On average, a variability percentage of 0.21% was observed. The Subolesin alignment with isolates from Yucatan, Nayarit, Queretaro, Chiapas, Sinaloa, Veracruz, Tamaulipas, and the reference Munoz strain, an identity average percentage of 99.87% and similarity percentage of 100% was observed in the aminoacid sequences. Seven from eight sequences presented identity percentage of 99.91% whereas for Nayarit the percentage was 99.39%. The average variability was 0.13%. Phylogenetic analysis did not show significant differences between sequences using the UPGMA method. Average percentage obtained by 10000 replicas by Bootstrap method for bmvdac and subolesin was up to 50%. Discussion and conclusion. This report represents the first research on the characterization of the variability for BmVDAC and Subolesin, two vaccine antigens against R. microplus isolates from different states of Mexico. Considering the low variability presented by the different R. microplus isolates sequences, we can conclude that BmVDAC and Subolesin are antigens that are conserved and can be considered as vaccine candidates. This information is relevant for antigen selection and vaccine design against R. microplus in Mexico. [ABSTRACT FROM AUTHOR]

Diamond back moth (Plutella xylostella) is a cosmopolitan pest that causes intense damage to Brassicaceae crops, round the world. Features such as the short cycle, many generations per year, high fertility rate, helped that it has acquired resistance to many chemical insecticides, pure and in mixtures, including a biological like Bacillus thuringiensis. Despite its importance and being very studied abroad, in Argentina few studies have been carried out. The article analyzes the progress of the studies of this pest in Argentina, and gives guidelines that help its management. [ABSTRACT FROM AUTHOR]

The common tick of cattle is the most important external parasite in South America because it is a vector of limiting diseases in the tropics. The fungi Metarhizium anisopliae and Beauveria bassiana are promising agents of biological control against induction of resistance to chemical ixodicides. An assay was conducted to evaluate the in vitro efficacy of three concentrations of M. anisopliae and B. bassiana on adult control of Rhipicephalus microplus. The study was carried out in the Laboratorio de Biocontroladores Pedro Ortiz from Instituto Nacional de Sanidad Agrícola Integral (INSAI), located in the peasant settlement Muralla I, Maturín, Monagas. Concentrations of 107, 108 and 109 conidia/mL of M. anisopliae and B. bassiana were prepared, and a treatment control with sterile water. Adult ticks were collected manually in bovines of different ages in the municipality of Freites, Anzoátegui state. A completely randomized design was used in a 3x3 factorial arrangement with five repetitions. Each experimental unit was constituted by five Petri dishes, containing 10 individuals each. The ticks were sprinkled with fungi and were incubated for 14 days at 27.5 ± 1°C and 85% relative humidity. It was determined that M. anisopliae and B. bassiana significantly affected the mortality of the theologins of R. microplus, in 84 and 77.33%, respectively. Metarhizium anisopliae was superior to B. bassiana, being the concentration of 109 conidia/mL the most effective, with 89.02% mortality and 88.23% efficacy. The percentage of hatching was reduced by 21.87% and 27.37% for the two fungal isolates, respectively. [ABSTRACT FROM AUTHOR]

One of the most important features of concrete, in addition to its mechanical properties, is its durability, which is associated to the in-service life of structures exposed to certain conditions or environments; this property is required to define the potential application fields and facilitate the commercialization of new cementing materials. In this study, the chemical resistance of a concrete based on a binary mixture of fly ash (FA) and blast furnace slag (GBFS) in an 80/20 ratio was evaluated. A concrete based on Portland cement (OPC) was used as a reference material. The compressive strength of Geo FA/GBFS at 28 days cured at room temperature was 42.9 MPa, 26% higher than that reported by the OPC concrete. Geo FA/GBFS exposed to sulfates does not show expansion, and the loss of compressive strength at 180 days aged of exposure was not significant (2%) compared to OPC concrete (39%). In the case of exposure to acids, FA/GBFS had a loss of resistance of 39% and OPC of up to 70%. These characteristics show the best performance of the activated material and its potential use in aggressive environments. [ABSTRACT FROM AUTHOR]

Gray cast iron is a material used in the fuel industry by its low cost, high mechanical strength and its manufacturing process. It has poor chemical resistance due to its high reactivity and susceptibility to corrosion. The use of biodiesel creates challenges of compatibility for this material, due to its oxidation and high hygroscopicity, which act as accelerators of corrosive processes. Within the applications this material has to offer, there are conditions of high temperature and pressure that affect the interaction with biodiesel and its process of corrosion. Gray cast iron samples were subjected to contact with palm biodiesel using the technique of static immersion in ambient conditions (18°C) and thermal cycles (Cyclic oxidation since18 to 200°C) and the corrosive effects were quantified. The material was immersed for a period of 450 hours and its weight was periodically recorded until the end of the test. The surface of the material was also analyzed by optical microscopy, scanning electron microscopy and x-ray diffraction. The results indicated a greater rate of corrosion on the cast iron for biodiesel fuel compared to regular diesel. In addition, it was observed that the thermal cycles accelerate the corrosive processes up to 4 times with respect to the ambient temperature. [ABSTRACT FROM AUTHOR]

Copyright of Revista ION is the property of Universidad Industrial de Santander and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Revista Española de Quimioterapia is the property of Sociedad Espanola de Quimioterapia and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Heavy-metal dissemination in superficial sediments and subground water is considered as a worldwide problem and its solution constitutes a challenge for the environmental cleaning-up. Several heavy-metals are essential nutrients required in trace concentrations for bacteria (range of nanomolar); however they are toxic in concentrations higher than micromolar. Heavy metals are considered as a biological threat for microorganisms because these elements are not biodegradable, contrary to organic pollutants. Only microorganisms encoding heavy metal resistance genetic determinants are able to survive in environments with high concentrations of these elements. Currently, heavy metals containing wastes are treated basically by chemical and physical methods but these are complicated, expensive and their efficiency is low. Release of great volumes of liquid and solid wastes which still contain high amounts of heavy metals is another of the disadvantages of the aforementioned methods. Bioremediation of effluents and waste waters using heavy metal resistant microorganisms based technologies may provide an alternative for environmental protection. Microorganisms might be effective metal accumulators and evidences support that the biomass-based clean-up processes are economically viable. However , many aspects of metal-microbe interactions remain unknown and unexploited in biotechnology. The application of bioremediation processes required a deeper knowledge of the biotransformation pathways and genetic determinants encoded by organisms from indigenous microbial communities of these ecosystems. The aim of this paper is to review the molecular mechanisms of heavy metal resistance described in bacteria and their applications in bioremediation. [ABSTRACT FROM AUTHOR]