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A gemini surfactant imidazoline type, namely N-(3-(2-fatty-4,5-dihydro-1H-imidazol-1-yl) propyl) fatty amide, has been obtained from the fatty acids contained in the mango seed and used as a CO2 corrosion inhibitor for API X-120 pipeline steel. Employed techniques involved potentiodynamic polarization curves, linear polarization resistance, and electrochemical impedance spectroscopy. These tests were supported by detailed scanning electronic microscopy (SEM) and Raman spectroscopy studies. It was found that obtained gemini surfactant greatly decreases the steel corrosion rate by retarding both anodic and cathodic electrochemical reactions, with an efficiency that increases with an increase in its concentration. Gemini surfactant inhibits the corrosion of steel by the adsorption mechanism, and it is adsorbed on to the steel surface according to a Langmuir model in a chemical type of adsorption. SEM and Raman results shown the presence of the inhibitor on the steel surface.
RESUMO
In this study, the performance evaluation of lanthanum compounds as corrosion inhibitors of vanadium salts was performed. The inhibitors tested were lanthanum acetate and La2O3. The performance of the inhibitors was tested using sodium metavanadate (NaVO3) as a corrosive medium at 700, 800, and 900 °C. The corrosion inhibitory effect was evaluated on the corrosion process of 304H stainless steel. The corrosion rate of the steel was determined by the mass loss technique after 100 h of immersion in the corrosive salt with and without the addition of the corrosion inhibitor. The results show that lanthanum compounds act as corrosion inhibitors of vanadium salts. The inhibitory effect increases by increasing the concentration and tends to decrease when increasing the test temperature. Lanthanum compounds act as excellent corrosion inhibitors due to their ability to stabilize vanadium cations. Vanadium is stabilized by forming a new compound, lanthanum vanadate (LaVO4), with a melting point much higher than the compounds formed when Mg or Ni compounds are used as corrosion inhibitors.
RESUMO
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.
RESUMO
BACKGROUND/AIMS: Microphthalmia-anophthalmia-coloboma (MAC) are congenital eye malformations causing a significant percentage of visually impairments in children. Although these anomalies can arise from prenatal exposure to teratogens, mutations in well-defined genes originate potentially heritable forms of MAC. Mutations in genes such as CHX10, GDF6, RAX, SOX2 and OTX2, among others, have been recognised in dominant or recessive MAC. SOX2 and OTX2 are the two most commonly mutated genes in monogenic MAC. However, as more numerous samples of MAC subjects would be analysed, a better estimation of the actual involvement of specific MAC-genes could be made. Here, a comprehensive mutational analysis of the CHX10, GDF6, RAX, SOX2 and OTX2 genes was performed in 50 MAC subjects. METHODS: PCR amplification and direct automated DNA sequencing of all five genes in 50 unrelated subjects. RESULTS: Eight mutations (16% prevalence) were recognised, including four GDF6 mutations (one novel), two novel RAX mutations, one novel OTX2 mutation and one SOX2 mutation. Anophthalmia and nanophthalmia, not previously associated with GDF6 mutations, were observed in two subjects carrying defects in this gene, expanding the spectrum of GDF6-linked ocular anomalies. CONCLUSION: Our study underscores the importance of genotyping large groups of patients from distinct ethnic origins for improving the estimation of the global involvement of particular MAC-causing genes.
Assuntos
Anormalidades do Olho/genética , Proteínas do Olho/genética , Mutação Puntual , Anoftalmia/genética , Criança , Pré-Escolar , Coloboma/genética , Análise Mutacional de DNA/métodos , Feminino , Predisposição Genética para Doença , Fator 6 de Diferenciação de Crescimento/genética , Proteínas de Homeodomínio/genética , Humanos , Lactente , Masculino , México , Microftalmia/genética , Pessoa de Meia-Idade , Fatores de Transcrição Otx/genética , Fatores de Transcrição SOXB1/genética , Fatores de Transcrição/genéticaRESUMO
Solitary plasmocytoma is a rare presentation of plasma cell dyscrasia. About 1% od the patients can present with a extramedullary plasmocytoma; although bone presentation is the most frequent, in some cases, soft tissue can be affected. Radiotherapy remain as the election treatment. A case of primary plasmocytoma of the larynx is presented. The patient is alive after radiotherapy. Discussion about the clinical differentiation and also a review of the literature is present.
Assuntos
Neoplasias Laríngeas , Plasmocitoma , Idoso , Humanos , Neoplasias Laríngeas/diagnóstico , Neoplasias Laríngeas/radioterapia , Masculino , Plasmocitoma/diagnóstico , Plasmocitoma/radioterapiaRESUMO
Está planteada la controversia entre el uso de la ventilación mecánica "profiláctica" y la extubación precoz de los pacientes sometidos a cirugía cardiovascular. En este trabajo analizamos morbilidad, mortalidad e incidencia de reintubación en 130 pacientes pediátricos operados en nuestro centro, en los cuales aplicamos parámetros definidos para decidir o no la extubación precoz al término de la operación. En los 93 pacientes extubados precozmente solo fueron reintubados 4 (4.3%), por complicaciones. La mortalidad de este grupo fue del 0%. En los 37 pacientes no extubados 27 (73%) presentaron complicaciones y la mortalidad fue 8 casos (21.6%). Concluimos que los parámetros de extubación precoz son confiables y que la ventilación mecánica no debe utilizarse en forma rutinaria e indiscriminada
Assuntos
Lactente , Pré-Escolar , Procedimentos Cirúrgicos Cardiovasculares , Intubação Intratraqueal , Pediatria , Respiração Artificial/métodosRESUMO
Está planteada la controversia entre el uso de la ventilación mecánica "profiláctica" y la extubación precoz de los pacientes sometidos a cirugía cardiovascular. En este trabajo analizamos morbilidad, mortalidad e incidencia de reintubación en 130 pacientes pediátricos operados en nuestro centro, en los cuales aplicamos parámetros definidos para decidir o no la extubación precoz al término de la operación. En los 93 pacientes extubados precozmente solo fueron reintubados 4 (4.3%), por complicaciones. La mortalidad de este grupo fue del 0%. En los 37 pacientes no extubados 27 (73%) presentaron complicaciones y la mortalidad fue 8 casos (21.6%). Concluimos que los parámetros de extubación precoz son confiables y que la ventilación mecánica no debe utilizarse en forma rutinaria e indiscriminada (AU)