Corrosion Induced on Aluminum by Biodiesel Components in Non-Oxygen Environments.

Biodiesel is a mixture of saturated and unsaturated Fatty Acid Methyl Esters (FAMEs) whose composition affects the corrosion behavior of metal containers during storage. This study examines the effect of the C=C bond present in selected FAMEs (Methyl Stearate, Methyl Oleate, and Methyl Linoleate) in aluminum corrosion in the absence of oxygen. First, mass loss assays were carried out at 100, 200, and 280 °C for 1000 h using pure Methyl Stearate (MS), 5% Methyl Oleate in Methyl Stearate (MS-5% MO), and 5% Methyl Linoleate in Methyl Stearate (MS-5% ML). Next, chemical changes in FAMEs were studied using FTIR, TGA, and GC/MS. SEM/EDS analysis allowed us to inspect the aluminum surfaces and their chemical characterization. We estimated higher corrosion rates for MS assays than those of unsaturated methyl ester mixtures. In a separate set of experiments, we used electrochemical techniques (potentiodynamic polarization, linear polarization resistance, and electrochemical impedance spectroscopy) to investigate aluminum corrosion induced by thermal-degraded products from FAMEs at 100, 200, and 280 °C for 300 h able to dissolve in aqueous extracts. These electrochemical experiments revealed that the products in the aqueous extracts from the unsaturated methyl ester mixture form a passive layer on the Al surface thicker than pure MS at the corresponding degradation temperatures.

Corrosion Inhibition in CO2-Saturated Brine by Nd3+ Ions.

This study reports the use of an inorganic corrosion inhibitor to mitigate dissolved CO2-induced corrosion. Using electrochemical techniques (polarization curves, open circuit potential, polarization resistance, and electrochemical impedance), the effect of adding Nd3+ ions on the corrosion resistance of X52 steel immersed in CO2-saturated brine at 20 °C and 60 °C was evaluated. The polarization curves showed that the Icorr values tend to decrease with increasing Nd3+ ion concentration, up to the optimal inhibition concentration, and that the corrosion potential increases at nobler values. Open circuit potential measurements showed a large increase in potential values immediately after the addition of the Nd3+ ions. Similarly, polarization resistance measurements showed similar trends. It was observed that regardless of temperature, Nd3+ ions can reduce the corrosion rate by more than 97% at doses as low as 0.001 M. Electrochemical impedance measurements confirmed the formation of a protective layer on the steel surface, which caused an increase in the magnitude of the impedance module and phase angle, which indicates an increase in the resistance to charge transfer and capacitive properties of the metallic surface. The characterization of the metallic surface showed that the protective layer was formed by Nd carbonates, whose formation was due to a CO2 capture process.

Sweet Corrosion Inhibition by CO2 Capture.

The most practical and economical way to combat the problems derived from CO2 corrosion (sweet corrosion) is the use of corrosion inhibitors of organic origin. Its main protection mechanism is based on its ability to adsorb on the metal surface, forming a barrier between the metal surface and the aggressive medium. However, despite its excellent performance, its inhibition efficiency can be compromised with the increase in temperature as well as the shear stresses. In this study, the use of an inorganic inhibitor is proposed that has not been considered as an inhibitor of sweet corrosion. The reported studies are based on using LaCl3 as a corrosion inhibitor. Its behavior was evaluated on 1018 carbon steel using electrochemical measurements, such as potentiodynamic polarization curves, open-circuit potential measurements, linear polarization resistance measurements, and electrochemical impedance. The results showed an inhibition efficiency of the sweet corrosion process greater than 95%, and that the inhibition mechanism was different from the classic corrosion process in CO2-free electrolytes. In this case, it was observed that the inhibitory capacity of the La3+ cations is based on a CO2-capture process and the precipitation of a barrier layer of lanthanum carbonate (La2(CO3)3).

Behavior of Ni20Cr Alloy in Molten Nitrate Salts.

This study reports the behavior of the Ni20Cr alloy in molten nitrate salts. Its behavior was evaluated in the eutectic mixture called Solar Salt (binary salt) and in a ternary mixture (90% Solar Salt and 10% lanthanum nitrate). The addition of lanthanum nitrate was performed to determine if the presence of the La3+ cation could act as a corrosion inhibitor. Through mass loss and potentiodynamic polarization studies, the effects of both electrolytes on the corrosion resistance of the alloy at 300, 400, and 500 °C and at exposure times of 250, 500, 750, and 1000 h were determined. The results showed an increase in the corrosivity of the ternary salt, due to a decrease in its melting point and an increase in the concentration of nitrate ions. However, it was observed that the La3+ cations formed a protective layer (La2O3) on the alloy surface. In both corrosive media, the Ni20Cr alloy showed excellent corrosion resistance, due to its ability to form protective layers of Cr2O3, NiO, and NiCr2O4, in addition to the presence of a layer of La2O3 in the case of the ternary salt.

Corrosion Behavior of Al Modified with Zn in Chloride Solution.

Aluminum-based alloys have been considered candidate materials for cathodic protection anodes. However, the Al-based alloys can form a layer of alumina, which is a drawback in a sacrificial anode. The anodes must exhibit uniform corrosion to achieve better performance. Aluminum can be alloyed with Zn to improve their performance. In this sense, in the present research, the electrochemical corrosion performance of Al-xZn alloys (x = 1.5, 3.5, and 5 at.% Zn) exposed to 3.5 wt.% NaCl for 24 h was evaluated. Polarization curves, linear polarization resistance (LPR), and electrochemical impedance spectroscopy (EIS) were used to identify the electrochemical behavior. The microstructure of the samples before the corrosion assessment was characterized by means of X-ray diffraction analyses (XRD) and scanning electron microscopy (SEM). In addition, microstructures of the corroded surfaces were characterized using X-ray mappings via SEM. Polarization curves indicated that Zn additions changed the pseudo-passivation behavior from what pure Al exhibited in a uniform dissolution regime. Furthermore, the addition of Zn shifted the corrosion potential to the active side and increased the corrosion rate. This behavior was consistent with the proportional decrease in polarization resistance (Rp) and charge transfer resistance (Rct) in the EIS. The analysis of EIS was done using a mathematical model related to an adsorption electrochemical mechanism. The adsorption of chloride at the Al-Zn alloy surface formed aluminum chloride intermediates, which controlled the rate of the process. The rate constants of the reactions of a proposed chemical mechanism were evaluated.

Electrochemical Performance of Fe40Al-X (X = Cr, Ti, Co, Ni) Alloys Exposed to Artificial Saliva.

Fe-Al intermetallic compounds have been considered excellent candidates as alternative alloys for various applications in corrosive environments compared to other Fe-based alloys. Their excellent corrosion resistance is due to the development of an Al-based passive layer. The performance of the passive layer can be improved by adding a third alloy element. Therefore, in this study the electrochemical performance of the Fe40Al intermetallic alloy modified by the addition of a third alloy element (Cr, Ti, Co, Ni) is evaluated. The corrosion resistance of intermetallic alloys has been evaluated by electrochemical tests (potentiodynamic polarization curves, and measurements of open circuit potential, linear polarization and electrochemical impedance) in artificial saliva. The performance of intermetallic alloys was compared with that of Ti. The results obtained showed that the addition of Ni and Ti substantially improves the corrosion resistance of the base intermetallic. The corrosion resistance shown is comparable or greater than that shown by Ti. However, the addition of Co reduces the corrosion resistance of the base intermetallic.

Synthesis of NdAlO3 Nanoparticles and Evaluation of the Catalytic Capacity for Biodiesel Synthesis.

Biodiesel synthesis was carried out via heterogeneous catalysis of canola oil with nanoparticles of a mixed oxide based on rare earths. The catalyst synthesis (NdAlO3) was carried out based on the method proposed by Pechini for the synthesis of nanoparticles. Thermogravimetric analysis-differential thermal analysis (TGA-DTA) analysis was performed on the nanoparticle precursor gel in order to establish the optimum conditions for its calcination, with these being of 800 °C over 24 h. A pure NdAlO3 compound with an approximate size of 100 nm was obtained. The products of the transesterification reaction were analyzed using gas chromatography, FTIR, and NMR. The optimum reaction conditions were determined, namely, the temperature effect, reaction time, methanol:oil mass ratio, and recyclability of the catalyst. These studies showed the following optimal conditions: 200 °C, 5 h, methanol:oil mass ratio of 6:1, and a constant decrease in the catalytic activity of the catalyst was observed for up to six reuses, which later remained constant at around a 50% conversion rate. The maximum biodiesel yield obtained with the optimum conditions was around 75%. Analysis of the reaction products showed that the residual oil showed a chemical composition different from that of the source oil, and that both the biodiesel and glycerol obtained were of high purity.

Circularity of the foveal avascular zone and its correlation with parafoveal vessel density, in subjects with and without diabetes.

PURPOSE: To characterize the distribution of the foveal avascular zone circularity and its correlation with parafoveal vessel density, in subjects with and without diabetes. METHODS: Observational, descriptive, cross-sectional, and prospective study; subjects without diabetes (Group 1), with diabetes without retinopathy (Group 2), or with diabetic retinopathy (Group 3) were included. Means of foveal avascular zone circularity and parafoveal vessel density were compared between groups (Kruskal-Wallis) and their correlation was calculated with Spearman's Rho test. RESULTS: Seventy-seven eyes; central vessel density mean was higher in Group 1 than in Group 2 and higher in Group 2 than in Group 3; inner and complete vessel density means were also higher in Group 2 than in Group 3. The mean of the foveal avascular zone circularity did not differ between groups, and in Group 3 it had a positive correlation with central (0.45), inner (0.56), and complete (0.53) vessel densities. CONCLUSIONS: Circularity does not differ between subjects with diabetes, with and without retinopathy, and has only a low correlation with parafoveal vessel density in people with diabetic retinopathy, which does not allow anticipating a reduction of vessel density in this disease.

OBJETIVO: Caracterizar la distribución de la circularidad de la zona avascular foveal y su correlación con la densidad vascular perifoveal, en sujetos con y sin diabetes. MÉTODO: Estudio observacional, descriptivo, transversal y prospectivo; se incluyeron sujetos sin diabetes (Grupo 1), con diabetes sin retinopatía (Grupo 2) y con retinopatía diabética (Grupo 3). Los promedios de circularidad de la zona avascular foveal y de la densidad vascular parafoveal se compararon entre grupos (Kruskal-Wallis), y se calculó su correlación mediante la prueba Rho de Spearman. RESULTADOS: Se estudiaron 77 ojos. El promedio de la densidad vascular central fue mayor en el Grupo 1 que en el Grupo 2, y mayor en el Grupo 2 que en el Grupo 3. Los promedios de la densidad vascular interna y completa también fueron mayores en el Grupo 2 que en el Grupo 3. El promedio de la circularidad de la zona avascular foveal no difirió entre grupos, y en el Grupo 3 tuvo una correlación positiva con la densidad vascular central (0.45), interna (0.56) y completa (0.53). CONCLUSIONES: La circularidad no difiere entre sujetos con y sin diabetes, con y sin retinopatía, y solo tiene una baja correlación con la densidad vascular parafoveal en sujetos con retinopatía diabética, lo cual no permite anticipar una reducción de la densidad vascular en esta enfermedad.

Modelling of Behavior for Inhibition Corrosion of Bronze Using Artificial Neural Network (ANN).

In this work, three models based on Artificial Neural Network (ANN) were developed to describe the behavior for the inhibition corrosion of bronze in 3.5% NaCl + 0.1 M Na2SO4, using the experimental data of Electrochemical Impedance Spectroscopy (EIS). The database was divided into training, validation, and test sets randomly. The parameters process used as the inputs of the ANN models were frequency, temperature, and inhibitor concentration. The outputs for each ANN model and the components in the EIS spectrum (Zre, Zim, and Zmod) were predicted. The transfer functions used for the learning process were the hyperbolic tangent sigmoid in the hidden layer and linear in the output layer, while the Levenberg-Marquardt algorithm was applied to determine the optimum values of the weights and biases. The statistical analysis of the results revealed that ANN models for Zre, Zim, and Zmod can successfully predict the inhibition corrosion behavior of bronze in different conditions, where what was considered included variability in temperature, frequency, and inhibitor concentration. In addition, these three input parameters were keys to describe the behavior according to a sensitivity analysis.

PROJECT HEAVEN: Preoperative Training in Virtual Reality.

A cephalosomatic anastomosis (CSA; also called HEAVEN: head anastomosis venture) has been proposed as an option for patients with neurological impairments, such as spinal cord injury (SCI), and terminal medical illnesses, for which medicine is currently powerless. Protocols to prepare a patient for life after CSA do not currently exist. However, methods used in conventional neurorehabilitation can be used as a reference for developing preparatory training. Studies on virtual reality (VR) technologies have documented VR's ability to enhance rehabilitation and improve the quality of recovery in patients with neurological disabilities. VR-augmented rehabilitation resulted in increased motivation towards performing functional training and improved the biopsychosocial state of patients. In addition, VR experiences coupled with haptic feedback promote neuroplasticity, resulting in the recovery of motor functions in neurologically-impaired individuals. To prepare the recipient psychologically for life after CSA, the development of VR experiences paired with haptic feedback is proposed. This proposal aims to innovate techniques in conventional neurorehabilitation to implement preoperative psychological training for the recipient of HEAVEN. Recipient's familiarity to body movements will prevent unexpected psychological reactions from occurring after the HEAVEN procedure.

Design of a strong cation exchange methodology for the evaluation of charge heterogeneity in glatiramer acetate.

Complex pharmaceuticals are in demand of competent analytical methods able to analyze charge heterogeneity as a critical quality attribute (CQA), in compliance with current regulatory expectations. A notorious example is glatiramer acetate (GA), a complex polypeptide mixture useful for the treatment of relapsing-remitting multiple sclerosis. This pharmaceutical challenges the current state of analytical technology in terms of the capacity to study their constituent species. Thus, a strong cation exchange methodology was designed under the lifecycle approach to support the establishment of GA identity, trough the evaluation of its chromatographic profile, which acts as a charge heterogeneity fingerprint. In this regard, a maximum relative margin of error of 5% for relative retention time and symmetry factor were proposed for the analytical target profile. The methodology met the proposed requirements after precision and specificity tests results, the former comprised of sensitivity and selectivity. Subsequently, method validation was conducted and showed that the method is able to differentiate between intact GA and heterogeneity profiles coming from stressed, fractioned or process-modified samples. In summary, these results provide evidence that the method is adequate to assess charge heterogeneity as a CQA of this complex pharmaceutical.

Zonas de exposición a plomo y la relación con marcadores biológicos en población de Bogotá / Areas of Exposure to Lead and the Relationship with Biological Markers in the Population of Bogotá / Áreas de exposição ao chumbo e a relação com marcadores biológicos na população de Bogotá

Introducción: El plomo es un metal con importantes propiedades fisicoquímicas, resistente a la corrosión, maleable y de bajo punto de fusión, altamente utilizado en la industria. Se considera potencialmente tóxico para los ecosistemas y los seres humanos; causa daños al sistema nervioso en desarrollo, principalmente en niños, en los cuales se presenta disminución de coeficiente intelectual y dificultades de aprendizaje y concentración. Objetivo: Establecer si hay una posible relación entre exposición ambiental a plomo y las concentraciones encontradas en marcadores biológicos de población general de Bogotá-Colombia, 2012/2013. Materiales y métodos: Estudio descriptivo como análisis secundario de las concentraciones de los marcadores biológicos de la investigación de "Prevalencia de mercurio y plomo en población general de Bogotá 2012/2013" y la construcción de un mapa de zonas de exposición ambiental por este contaminante, para determinar posibles relaciones de exposición por medio de razones de prevalencia. Resultados: Edad promedio de 46,5 años; rango (3-91); 74,8 % mujeres; plomo en adultos 8,59 µg/dL, y plomo en niños 9,04 µg/dL. Se encontró asociación entre las zonas de exposición ambiental a plomo y alguna concentración de plomo en sangre. La zona de exposición alta presentó la mayor prevalencia de alguna concentración de plomo en sangre. Conclusión: Los niveles elevados de plomo en sangre en Bogotá se encuentran concentrados hacia el sur de la ciudad, razón por la cual se debe continuar con estudios que expliquen las causas de dichas concentraciones y el control que se debe generar en las fuentes.

Introduction: Lead is an important metal, corrosion resistant, pliable and low melting physicochemical properties, highly used in industry. It is considered potentially toxic to humans and ecosystems, cause damage to the developing nervous system, especially in children in whom decreased intelligence quotient and learning difficulties and concentration system is presented. Objective: The aim of this paper is establish if there is a possible relationship between environmental exposure to lead and the concentrations found in biological markers of general population of Bogotá-Colombia 2012/2013. Materials and methods: Descriptive study as a secondary analysis of the concentrations of the biological markers, obtained from the investigation of "Prevalence of mercury and lead in the general population of Bogotá 2012/2013" and the construction of a map of environmental exposure zones by this pollutant to determine Possible exposure relationships through prevalence reasons. Results. Mean age 46.5 years (range 3-91), 74.8% women; 8.59 mg/dL lead in adults, 9.04 mg /d L lead in children. Association between the areas of environmental lead exposure and a blood lead concentration was found. The high exposure zone has the highest prevalence of blood lead concentration. Conclution: Elevated blood lead levels in Bogota are concentrated south of the city, why should continue with studies that explain the causes of these concentrations and the control that must be generated in the sources.

à corrosão, maleável e de baixo ponto de fusão, altamente utilizado na indústria. É considerado potencialmente tóxico para ecossistemas e seres humanos, causando danos ao sistema nervoso em desenvolvimento, principalmente em crianças nas quais há diminuição do QI e dificuldades de aprendizado e concentração. Objetivo: Estabelecer se existe uma possível relação entre a exposição ambiental ao chumbo e as concentrações encontradas nos marcadores biológicos da população geral de Bogotá-Colômbia, 2012/2013. Materiais e Métodos: Estudo descritivo como uma análise secundária de concentrações de pesquisa marcadores biológicos "Prevalência de mercúrio e chumbo na população em geral de Bogotá 2012/2013" ea construção de um mapa de áreas de exposição ambiental este contaminante para determinar Possíveis relações de exposição por razões de prevalência. Resultados: Idade média 46,5 anos, faixa (3-91), 74,8 % mulheres, chumbo em adultos 8,59 µg / dL e 9,04 µg / dL de chumbo em crianças. Foi encontrada uma associação entre as zonas de exposição ambiental para levar e alguma concentração de chumbo no sangue. A zona de alta exposição apresentou a maior prevalência de concentração de chumbo no sangue. Conclusão: Nível de chumbo no sangue elevados em Bogotá estão concentradas ao sul da cidade, por isso deve continuar com os estudos que explicam as causas dessas concentrações e controlar a ser gerado nas fuentes.

Biomarcadores de mercurio y su relación con la edad, en Bogotá, 2014 / Mercury Biomarkers and Age in Bogotá, 2014 / Biomarcadores de Mercúrio e a Sua Relação com a Idade, Bogotá, 2014

Introducción: El mercurio se encuentra en forma natural o antrópica, con capacidad de acumularse en el organismo (bioacumulación) y concentrarse en las cadenas alimentarias (biomagnificación),especialmente en peces. Materiales y métodos: Estudio descriptivo, análisis secundario de biomarcadores de mercurio y su relación con la edad, a partir del estudio "Prevalencia de mercurio y plomo en población general de Bogotá 2012/2013". Resultados:Participaron 401 personas; el promedio de edad fue de 46,5 años; el 74,8 % fueron mujeres. Los valores promedio de concentración de mercurio fueron 0,294 µg/L en orina, 3,127 µg/L en sangre y 1,003 µg/g en cabello. La prevalencia general de personas con niveles que superaron los valores límite de referencia internacional dados por la Organización Mundial de la Salud (OMS) y la Agencia de Protección Ambiental (EPA), para mercurio fue de 13,5 %. Se presentó correlación positiva entre la edad y las concentraciones de mercurio en sangre y en cabello, p < 0,05. Discusión: Al encontrar el aumento de la edad con el incremento de los niveles de mercurio en sangre y cabello puede explicarse por el proceso conocido como bioacumulación; aunque el cuerpo humano está diseñado para eliminar de manera natural contaminantes como el mercurio, dicha eliminación es muy lenta, y con el paso de los años el cuerpo se satura y supera la capacidad del organismo. Debe fortalecerse el desarrollo de sistemas de vigilancia epidemiológica que permitan avanzar en la detección temprana de posibles casos de intoxicación derivados de la exposición ambiental a mercurio.

Introduction: Mercury is a heavy metal released naturally and anthropically in the environment; it may change by microbial metabolism and become methyl-mercury accumulated within the organisms (bioaccumulation) and concentrated within food chains (biomagnification), especially fish. Due to bioaccumulation, its elimination over time is more difficult and slower because the system is saturated exceeding the removal ability of the organism. Materials and methods: A descriptive study and a secondary analysis of mercury biomarkers related to age from the study "Prevalence of mercury and lead in general population of Bogota 2012/2013". Results: Measurements were made with 401 people, whose average age was 46.5 years; 74.8 percent women. The mean values of Hg concentration, 0.294 µg/L in urine; 3.127 µg/L in blood; 1.003 µg/g in hair. Overall prevalence of people with levels exceeding the international reference limit values given by WHO and EPA for Hg was 13.5 percent. There was a positive correlation between age and Hg concentrations in blood and hair, P < 0.05. Discussion: Hg-increased levels found in blood and hair related to the increased age can be explained by bioaccumulation process since the human body has been created to remove naturally contaminants such as Hg, and this is very slow and over time the body saturates exceeding the ability to remove them. Therefore, the development of epidemiological monitoring systems should be strengthened to allow a timely exposure of probable events of intoxication caused by environmental Hg exposure, whose emphasis should be on the most vulnerable population.

Introdução: O mercúrio encontra-se presente no ambiente de forma natural ou antrópica; este pode mudar por metabolismo microbiano e se converter em metil-mercúrio com capacidade de se acumular nos organismos (bioacumulação) e se concentrar na cadeia alimentar (bio-magnificação), especialmente em peixes. Devido à bioacumulação, sua eliminação com o andar do tempo é mais difícil e lenta, pois o sistema satura-se superando a sua capacidade de eliminação do organismo. Materiais e métodos: Estudo descritivo, análise secundário de biomarcadores de mercúrio e a sua relação com a idade a partir do estudo "Prevalência de mercúrio e chumbo na população geral de Bogotá 2012/2013". Resultados: Foram realizadas medições em 401 pessoas, cuja média de idade foi 46,5 anos; o 74,8% foram mulheres. Os valores médios de concentração de Hg foram 0,294 µg/L na urina, 3,127 µg/L no sangue; 1,003 µg/g no cabelo. A prevalência geral de pessoas com níveis que superaram os valores limites de referência internacional, dados pela OMS e EPA para Hg foi de 13,5%. Teve correlação positiva entre a idade e as concentrações de Hg no sangue e cabelo P < 0,05. Discussão: O achado do aumento dos níveis de Hg no sangue e no cabelo respeito do aumento da idade pode se explicar pelo processo nomeado bio- acumulação, pois o corpo humano embora esenhado para eliminar de jeito natural contaminantes como o Hg, é muito lento e com o decorrer do tempo o corpo satura-se superando a sua capacidade para elimina-los. A vista disso, deve se fortalecer o desenvolvimento de sistemas de vigilância epidemiológica que permitam avançar na detecçãooportuna de possíveis casos de intoxicação derivados da exposição ambiental a Hg, cujo ênfase deve ser orientado à população mais vulnerável.

Zonas de exposición ambiental a mercurio y relación con marcadores biológicos en población de Bogotá / Environmental Areas Exposed to Mercury and a Relationship Against Biomarkers in Bogotá Population / Zonas de Exposição Ambiental a Mercúrio e Relação com Marcadores Biológicos na População de Bogotá

Introducción: El mercurio es un metal pesado, potencialmente tóxico para los ecosistemas y los seres humanos. En Bogotá no se realizan mediciones directas y no se cuenta con un mapa distrital de concentraciones de dicho contaminante. Objetivo: Establecer si hay una posible relación entre las zonas de exposición ambiental a mercurio y las concentraciones encontradas en marcadores biológicos de población general de Bogotá-Colombia, 2012/2013. Materiales y métodos: Estudio descriptivo como análisis secundario de las concentraciones de los marcadores biológicos de mercurio obtenidas de la investigación "Prevalencia de mercurio y plomo en población general de Bogotá 2012/2013" y la construcción de un mapa de zonas de exposición ambiental por este contaminante, con el fin de determinar posibles relaciones de exposición, por medio de razones de prevalencia y prueba 2. Resultados: Edad promedio de 46,5 años, rango de 3-91; el 74,8 % eran mujeres. Promedio de mercurio de 0,29 µg/L en orina, 3,13 µg/L en sangre y 1 µg/g en cabello. Se encontró que los promedios de las concentraciones de mercurio fueron superiores en la zona de exposición alta; sin embargo, no se presentaron diferencias estadísticamente significativas entre las concentraciones de mercurio por zonas de exposición. Conclusión: La contaminación por Hg es una problemática de toda la ciudad, posiblemente asociada con variables no ambientales que no fueron tenidas en cuenta en el estudio, como el consumo de productos derivados de la pesca. Se requiere realizar mediciones directas de mercurio en aire para generar mapas de exposición al contaminante en la ciudad.

Introduction: Mercury is a potentially toxic heavy metal for ecosystems and humans. In Bogota area, there are not direct measurements and there is not any district map of concentrations of such a pollutant. Objective: Establishing a possible relation between areas of environmental exposed against mercury and the relevant concentrations found in biomarkers of overall population in Bogota, Colombia, 2012/2013. Materials and methods: A descriptive study as a secondary analysis of the mercury biomarker concentrations got from research "Mercury-and-lead prevalence in overall population, Bogota 2012/2013", and mapping environmental exposure areas by this pollutant in order to establish potential exposure ratios through prevalence ratios and chi-square test. Results: 46,5-year mean age; range (3-91); 74,8 % women, average mercury 0,29 µg/L urine, 3,13 µg/L blood, 1 µg/g hair, resulting mercury concentrations averages higher within the high exposure area, however, there were no statistically significant differences between mercury concentrations by exposure areas. Conclusion: Hg contamination is a problematic issue of the whole city, maybe related to non-environmental variables not taken into account in the study, such as the consumption of fishery products. Direct air mercury measurements are required to map pollutant exposure against the city.

Introdução: O mercúrio é um metal pesado potencialmente tóxico para os ecossistemas e os seres humanos. Em Bogotá não se realizam medições diretas e também não se conta com um mapa distrital de concentrações do dito contaminante. Objetivo: Estabelecer si existe uma possível relação entre zonas de exposição ambiental a mercúrio e as concentrações achadas nos marcadores biológicos da população geral de Bogotá-Colômbia, 2012/2013. Materiais e métodos: Estudo descritivo como análise secundário das concentrações dos marcadores biológicos de mercúrio obtidas da pesquisa de "Prevalência de mercúrio e chumbo na população geral de Bogotá 2012/2013" e a elaboração de um mapa de zonas de exposição ambiental por esse contaminante para determinar possíveis relações de exposição através de razões de prevalência e prova 2. Resultados: Idade média 46,5 anos; rango 3-91; 74,8 % mulheres média de mercúrio, 0,29 µg/L urina; 3,13 µg/L sangue; 1 µg/g cabelos. Achou-se que as médias das concentrações de mercúrio foram superiores na zona de alta exposição, no entanto, não se apresentaram diferencias estatisticamente significativas entre as concentrações de mercúrio por zonas de exposição. Conclusão: A contaminação por Hg é uma problemática da cidade toda, possivelmente associada com variáveis não ambientais que não foram levadas em conta no estudo, como o consumo de produtos derivados da pesca. Precisam-se realizar medições diretas de mercúrio no ar a fim de gerar mapas de exposição ao contaminante na cidade.

Increased homocysteine levels correlate with the communication deficit in children with autism spectrum disorder.

The clinical significance of high levels of homocysteine in autism spectrum disorder (ASD) is unknown. An experimental study was conducted in order to evaluate the concentration of homocysteine in children with ASD and typically developing children and to analyse any relationships with the severity of core symptoms of ASD and other clinical features (drugs, co-morbidities, gender, age, diet). Core symptoms of autism were evaluated by DSM-IV criteria. Homocysteine, glutathione, methionine, 3-nitrotyrosine were measured in urine. The increase in homocysteine concentration was significantly and directly correlated with the severity of the deficit in communication skills, but was unrelated to deficit in socialisation or repetitive/restricted behaviour. Urinary homocysteine concentration may be a possible biomarker for communication deficits in ASD and a potential diagnostic tool useful to evaluate new treatment options since no treatment for core symptoms of ASD are available.

Analysis of recombinant monoclonal antibodies by capillary zone electrophoresis.

Analytical platforms that characterize charge heterogeneity in therapeutic proteins, such as mAbs, are important tools that can be used to define quality attributes. CZE separates protein moieties close to their native state and is a valuable physicochemical analytical method that can be used in parallel with other orthogonal methods for characterization and comparability. In this study, custom conditions for the analysis of charge heterogeneity of two mAbs were developed with regard to critical parameters in the BGE, running conditions, and sample treatment. The method application was tested for up to four mAbs and one mAb fragment. The electropherograms showed specific profiles and contrasting levels of basic and acidic isoforms with respect to the main isoform. Issues that surround this method, such as peak tailing and capillary lifetime, are summarized. Using this method, the identities of rituximab and trastuzumab were confirmed, based on the correspondence between the biosimilars and reference products, noninterference of the sample matrix, and the ability to separate spiked samples of related mAbs. The RSD of the isoform content and migration time for the method repeatability were less than 2 and 1%, respectively.

Protease activities of Acanthamoeba polyphaga and Acanthamoeba castellanii.

Acanthamoeba spp. are free-living amoebae that cause amoebic granulomatous encephalitis, skin lesions, and ocular amoebic keratitis in humans. Several authors have suggested that proteases could play a role in the pathogenesis of these diseases. In the present work, we performed a partial biochemical characterization of proteases in crude extracts of Acanthamoeba spp. and in conditioned medium using 7.5% SDS-PAGE copolymerized with 0.1% m/v gelatin as substrate. We distinguished a total of 17 bands with proteolytic activity distributed in two species of Acanthamoeba. The bands ranged from 30 to 188 kDa in A. castellanii and from 34 to 144 kDa in A. polyphaga. Additionally, we showed that the pattern of protease activity differed in the two species of Acanthamoeba when pH was altered. By using protease inhibitors, we found that the proteolytic activities belonged mostly to the serine protease family and secondly to cysteine proteases and that the proteolytic activities from A. castellanii were higher than those in A. polyphaga. Furthermore, aprotinin was found to inhibit crude extract protease activity on Madin-Darby canine kidney (MDCK) monolayers. These data suggest that protease patterns could be more complex than previously reported.

Obtención de una harina de pulido de arroz desengrasado con bajo contenido de fibra neutro detergente / Obtaining a flour with low content of neutral detergent fibre from defatted rice bran

Por su contenido de proteínas y minerales, el pulido de arroz (PA) podría ser empleado en alimentación humana o animal si son eliminados el aceite y las fracciones con alto contenido de fibra. Para ello se realizó la extracción sólido-líquido al PA, con una eficiencia en la extracción del extracto etéreo del 95,6 por ciento, a fin de obtener el pulido de arroz desengranado (PAD). Se efectuó la clasificación granulométrica del PA y PAD, y de cada fracción se determinó su composición química proximal: proteína, extracto etéreo, cenizas, fibra neutro detergente (FND) y extracto libre de nitrógeno (ELN). El PA tiene un alto contenido de fracciones gruesas (>70 por ciento corresponden a partículas con tamaño de malla > 120), mientras que el PAD posee una distribución de partícula más uniforme y un contenido de grasas < 10g-kg -¹. Los perfiles del análisis químico para PA y PAD, muestran diferencias en FND y ELN, e indican que las partículas finas están constituidas principalmente por ELN (600g-kg-¹), y las partículas gruesas tienen alto contenido de FND (420g-kg-¹). El tamaño de partícula con alto y bajo contenido de fibra es el punto de inflexión de los perfiles de FND y ELN del PAD, que corresponde a la malla 180 (0,092 mm). Del PAD se puede obtener un 36 por ciento de harina (fracción 2) con 126,6g-kg-¹ de proteína y 180g-kg-1 de FND, y un 64 por ciento de harina (fracción 1) con 130.3g-kg-¹ de proteína y alto contenido de FND (420g-kg-¹). Esta harina ameritaría estudios posteriores respecto de su potencial en alimentación humana o en aplicaciones para alimentación animal

Entamoeba histolytica: acute granulomatous intestinal lesions in normal and neutrophil-depleted mice.

To study the role of neutrophils in the innate resistance to Entamoeba histolytica intestinal infection in mice, animals were treated with anti-neutrophil monoclonal antibodies prior to intracecal parasite inoculation and the resulting lesions were compared with normal mice that had been equally infected. In contrast to our previous finding that neutrophils are critical in eliminating E. histolytica infection in the liver, we show here that neutrophils are not absolutely required to eliminate E. histolytica infection from the intestine. Although the neutrophils are not critical for resolution of the E. histolytica infection, neutrophils do appear to provide some measure of protection as the intestinal amoeba burden was higher at early timepoints after infection in the neutropenic animals. In addition, we found that while both the normal and the neutrophil-depleted mice developed ulcerative lesions in the colon, the neutropenic mice had an increased frequency of granulomas that formed around the amoeba. Thus, our findings appear to be the first evidence showing that granulomatous inflammation can occur after intestinal infection in mice using axenically cultured amoeba.

Surface redistribution of interferon ç-receptor and its colocatization with the actin cytoskeleton

Background. Specific antibodies for human IFNç-R1 were used to examine its mobilization in Colo 205 cells. Methods. We report here that antibody-IFNç-R1 complex induced capping and actin colocalization. Pretreatment witrh cytochalasin D abolished this capping. To define the role of the IFNç-R1 in the possible interaction with actin, transfected murine fibroblasts cell line with human cDNA IFNç-R1 were used. Results. Only those cells expressing the full receptor and cultured in suspension polarized the receptor and this colocalized with actin filaments. Nevertheless, cells truncated in their intracellular domain displayed no capping and actin remained unaltered either in suspension or in monolayer culture conditions. As mutant bearing an IFNç-R1 with substitutions in positions 270-271 of the intracellular domain redistributed both IFNç-R1 and actin as micropatches instead of capping. Mutation in 256-303 residues resulted in IFNç-R1 microaggregates but actin remained unchanged. Conclusions. These experimental models allowed us to highlight an apparent receptormicrofilament association through the intracellular domain of IFNç-R1, and to specifically locate it within the intracellular region 256-303 that has been identified as relevant for ligand-receptor internalization and biological function