RESUMEN
RESUMO Considerado um poluente prioritário de reconhecida toxicidade e recalcitrância, o 2,4-dinitrofenol (2,4-DNF) presente em águas residuárias dificulta tratamentos convencionais, especialmente os de princípio biológico, como lagoas aeradas e sistema de lodos ativados. Em função de sua potencialidade de transformar a estrutura de poluentes em elementos de capacidade poluidora reduzida, os processos oxidativos avançados (POAs) representam atualmente uma alternativa para o tratamento de efluentes contaminados com compostos dessa natureza. A presente pesquisa teve como objetivo realizar estudos de degradação de 2,4-DNF em solução aquosa por meio de processos de oxidação avançada do tipo Fenton utilizando uma fonte não convencional de ferro na forma de um resíduo siderúrgico (carepa de aço). A condução de um delineamento experimental fundamentado em planejamento fatorial de experimentos revelou que as variáveis quantidade de peróxido de hidrogênio e de carepa influenciaram significativamente a degradação de 2,4-DNF, proporcionando, em condições otimizadas (20 g de carepa, 0,5 mL de H2O2 em pH 3), elevada eficiência na degradação tanto do composto modelo quanto de seus intermediários reacionais, tendo reduzido também a toxicidade aguda medida na forma de inibição de crescimento de E. coli. Ensaios adicionais sugeriram que os mecanismos reacionais pelos quais ocorre a degradação do 2,4-DNF são mediados tanto pela superfície das partículas de carepa quanto pelo ferro lixiviado, caracterizando o processo como uma combinação de oxidação homogênea e heterogênea. Finalmente, ensaios de reusabilidade e operação em reator de fluxo contínuo sugeriram significativa potencialidade do sistema carepa/H2O2.
ABSTRACT Considered a priority pollutant of recognized toxicity and recalcitrance, 2.4-dinitrophenol (2.4-DNP) present in wastewater hinders conventional treatments such as filtration, chemical coagulation, activated sludge system and activated carbon adsorption. Due to the potential of advanced oxidation processes (AOP) to transform the structure of pollutants into elements of reduced pollutant capacity, they presently represent an alternative for the treatment of effluents contaminated with these compounds. The present research aimed to study the degradation of 2.4-DNP in aqueous solution through advanced Fenton-type oxidation processes, using an unconventional source of iron in the form of a steel residue (steel waste). The conduction of an experimental design based on the factorial planning of experiments revealed that the variables hydrogen peroxide quantity and scale significantly influenced 2.4-DNF degradation, providing, under optimized conditions (20 g of steel waste, 0.5 mL of H2O2 at pH 3) high degradation efficiency of both the model compound and its reaction intermediates, as well as reducing acute toxicity, measured as E. coli growth inhibition. Further trials have suggested that the reaction mechanisms by which 2.4-DNF degradation occurs are mediated by both the surface of steel waste particles and the leached iron, characterizing the process as a combination of homogeneous and heterogeneous oxidation. Finally, reusability and continuous flow reactor operation tests suggested the significant potential of the steel waste/ H2O2 system.
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Abstract The accumulation of heavy metals and of pesticides in the soil have a negative impact on Capsicum chinense var. Aji Mochero and Capsicum baccatum var. pendulum Bishop's Crown species, the present work highlighting the exerted influence on the superoxid-dismutase activity, catalase and peroxidase - as enzymes implied in the removal of H2O2, of O2- radical and of ion HO- that have devastating effects on the vegetable cell, on the Krebs cycle's dehydrogenases - as main way to produce energy, respectively of the chlorophyll a, b and carotenes - as photoassimilatory pigments, but also as biologic antioxidants.
Asunto(s)
Capsicum , Estrés Oxidativo , Metales Pesados/química , Dinitrofenoles/químicaRESUMEN
Rotenone is a specific inhibitor of the NADH dehydrogenase complex. In mitochondria, rotenone inhibitsthe oxidation of NADH to NAD, thereby blocking the oxidation of NAD and the substrates such asglutamate, alpha-ketoglutarate, and pyruvate. Rotenone also inhibits the mitochondrial respiratory chainbetween diphosphopyridine nucleotide and flavine.2, 4-Dinitrophenol – (DNP) is lipophilic weak acids that pick up a proton, transport across the mitochondrialinner membrane into the matrix, deprotonate, then exit as anions before repeating the catalytic cycle,and dissipating the proton gradient. In this situation, electrons continue to pass through the electrontransport system, reduce oxygen to water and metabolic rate, heat are increased, but ATP is lesssynthesized in this process.The macrolide antibiotic - oligomycin binds to the surface of the c8-10 ring of the Fo domain of ATPsynthase, making contact with two neighboring molecules and blocking proton flow, which explains theinhibitory effect on ATP synthesis. Intraperitoneal injection of oligomycin into the rat (0.5 mg per kg)reduces the oxygen consumption by about 50%; decreases ATP production by the aerobic pathway andincreases formation of lactate in blood serum. These changes may cause a decelerated metabolism andan increased formation of free radicals or ROS in membranes.
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To provide pharmacological evidence of plumeria rubra as antipyretic agent in practice many parts of Pakistan. Antipyretic effect of methanolic extract of the bark of plumeria rubra was investigated.on yeast , dinitrophenol and E-coli induced model. Intraperitoneal administration of yeast, dinitrophenol and E-coli in albino rabbits leads to pyrexia. Intraperitoneal administration of methanolic extract of the bark of plumeria rubra at a dose 100mg/kg body weight were shown significantly reduce the elevated body temperature of rabbit in yeast induced model which was compared with aspirin (Standard Drug) and solvent used. In dinitrophenol induced pyrexia, mixture of verapamil (2mg/kg) and Plumeria rubra (50mg/kg), while in In E-coli induced pyrexia, mixture of Ciproflaxacin (10mg/kg) and Plumeria rubra (50mg/kg), significantly reduced the elevated temperature in all models as compared to the standard drug Aspirin.
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Two simple and selective spectrophotometric methods have been proposed for the determination of amikacin sulfate, gentamicin sulfate, kanamycin sulfate, streptomycin sulfate, neomycin sulfate and tobramycin in pure forms and in their pharmaceutical formulations. Both methods are based on the proton transfer from the Lewis acid such as 2,4,6-trinitrophenol (picric acid; PA) or 2,4-dinitrophenol (2,4-DNP) to the primary amino group of aminoglycosides as Lewis base with formation of yellow ion-pair complexes. Different variables and parameters affecting the reactions were studied and optimized. Beer’s plots were obeyed in a general concentration range of 2.5-140 and 2.5–100 μg mL-1 with 2,4-DNP and PA, respectively, with correlation coefficients not less than 0.9991. The proposed methods were successfully applied to the analysis of the cited drugs in their dosage forms. The proposed methods were validated according to ICH and USP guidelines with respect to specificity, linearity, accuracy, precision, robustness and ruggedness.
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Se obtuvo un material adsorbente mediante tratamiento térmico de hueso bovino. Este carbonizado presenta un área superficial de 171 m²g-1, características texturales de un material mesoporoso y presencia del componente principal de la matriz ósea: hidroxiapatita. Se llevó a cabo la adsorción de 2,4-di-nitrofenol sobre el carbonizado en solución acuosa, en función del tiempo, y se determinó la cinética de adsorción por los modelos de seudo primer y seudo segundo orden. Además, se identificó el mecanismo de difusión mediante el modelo de difusión intrapartícula. Se observa que los datos cinéticos experimentales tienen mayor correlación con el modelo de seudo segundo orden. El modelo de difusión intrapartícula muestra que el proceso de adsorción está gobernado por la etapa en donde el mecanismo de difusión de partícula es la limitante de la velocidad.
Adsorbent material was obtained by heat treatment of bovine bone. This char has a surface area of 171 m²g-1, textural characteristics of a mesoporous material, and presence of the principal component of bone matrix-hidroxiapatite. The 2,4-dinitrophenol adsorption from aqueous solution in function of time was carried on the charred and determined the kinetics of adsorption by models of pseudo-first and pseudo second order. Additionally, we identified the diffusion mechanism through intraparticle diffusion model. The experimental kinetic data are more correlated with the pseudo second order model. The intraparticle diffusion model shows that the adsorption process is governed by stage where the diffusion particle mechanism is the rate-limiting.
Se obteve um material adsorbente mediante tratamento térmico de osso bovino. Este carbonizado apresenta um área superficial de 171 m²g-1, características texturais de um material mesoporoso e presença do componente principal da matriz óssea: hidroxiapatita. A adsorção de 2,4-dinitrofenol desde solução acuosa, em função do tempo, se levou a cabo sobre o carbonizado e se determinou a cinética de adsorção pelos modelos de seudo primeiro e seudo segundo ordem. Além disso, identifica-se o mecanismo de difusão mediante o modelo de difusão intrapartícula. Se observa que os dados cinéticos experimentais têm maior correlação com o modelo de seudo segundo ordem. O modelo de difusão intrapartícula mostra que o processo de adsorção está governado pela etapa onde o mecanismo de difusão de partícula é a limitante da velocidade.
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To characterize cytosolic Ca2+ fluctuations under metabolic inhibition, rat ventricular myocytes were exposed to 200microM 2, 4-dinitrophenol (DNP), and mitochondrial Ca2+, mitochondrial membrane potential (delta psi m), and cytosolic Ca2+ were measured, using Rhod-2 AM, TMRE, and Fluo-4 AM fluorescent dyes, respectively, by Laser Scanning Confocal Microscopy (LSCM). Furthermore, the role of sarcolemmal Na+/Ca2+ exchange (NCX) in cytosolic Ca2+ efflux was studied in KB-R7943 and Na+-free normal Tyrode's solution (143 mM LiCl ). When DNP was applied to cells loaded with Fluo-4 AM, Fluo-4 AM fluorescence intensity initially increased by 70+/-10% within 70+/-10 s, and later by 400+/-200% at 850+/-46 s. Fluorescence intensity of both Rhod-2 AM and TMRE were initially decreased by DNP, coincident with the initial increase of Fluo-4 AM fluorescence intensity. When sarcoplasmic reticulum (SR) Ca2+ was depleted by 1microM thapsigargin plus 10microM ryanodine, the initial increase of Fluo-4 AM fluorescence intensity was unaffected, however, the subsequent progressive increase was abolished. KB-R7943 delayed both the first and the second phases of cytosolic Ca2+ overload, while Na+-free solution accelerated the second. The above results suggest that: 1) the initial rise in cytosolic Ca2+ under DNP results from mitochondrial depolarization; 2) the secondary increase is caused by progressive Ca2+ release from SR; 3) NCX plays an important role in transient cytosolic Ca2+ shifts under metabolic inhibition with DNP.