Caracterizaci��n de la exposici��n ocupacional a los gases, di��xido de azufre (so2), sulfuro de hidr��geno (h2s), y mon��xido de carbono (co), y la percepci��n de salud de los trabajadores, en una empresa del sector hidrocarburo en Colombia

En el proceso de extracci��n de petr��leo (crudo) deben realizarse tratamientos f��sicos y qu��micos en estaciones de recolecci��n del hidrocarburo con el fin de garantizar su calidad antes de su entrega para el transporte y comercializaci��n. Para la realizaci��n de esta actividad el personal operativo requerido (operadores) debe realizar diferentes actividades, tales como ronda operacional, verificaci��n de sistemas de almacenamiento del crudo, agua residual del proceso e insumos qu��micos utilizados en su tratamiento y manipulaci��n de facilidades en las estaciones de recolecci��n, entre otras. Como resultados de las actividades rutinarias los operadores est��n expuestos a factores de riesgo qu��mico asociados a gases y vapores org��nicos generados en los procesos de tratamiento del crudo. En el presente trabajo se realizaron mediciones de calidad de aire e higiene industrial en diferentes estaciones tratamiento de crudo, con el prop��sito de evaluar los niveles de exposici��n de los operadores a gases y vapores de hidrocarburos durante el proceso de tratamiento de crudo y dar respuesta a la siguiente pregunta: ��existe relaci��n entre la exposici��n ocupacional, las emisiones atmosf��ricas de gases (SO2, CO, H2S) y la percepci��n de afectaci��n de la salud de los trabajadores que se encuentran expuestos durante la actividad laboral, en una empresa del sector de hidrocarburos? Se realiz�� un estudio de corte transversal, mediante la aplicaci��n de cuestionarios sobre las condiciones de trabajo y de salud a 30 trabajadores que laboran en una estaci��n de tratamiento de crudo de una compa����a del sector de hidrocarburos. Los operadores objeto de estudio laboran en turnos rotativos, han estado vinculados con la compa����a por m��s de dos a��os y tienen contrato directo, adicionalmente, se identificaron los factores de riesgos ambientales y ocupacionales para el grupo de trabajadores y se realiz�� una revisi��n de los informes de medici��n de higiene industrial y de calidad de aire de las estaciones donde labora el personal seleccionado con el fin de establecer si los resultados se relacionan. Los resultados obtenidos indican que el 100% de los trabajadores son de g��nero masculino y se desempe��an en cargos de operadores, recorredores de pozos de crudo y supervisores. El 97% de los operadores tiene m��s de cuarenta a��os de edad y el 80% de los mismos ha laborado por m��s de 6 a��os en la compa����a. Acerca de la percepci��n de los trabajadores sobre su estado de salud el 90% afirma que su salud es buena, el 97% respondi�� que no presenta problemas respiratorios, el 23% manifiesta que presenta trastornos dermatol��gicos y el 27% indican que presenta dolor de cabeza constante. De la revisi��n de los informes de calidad de aire disponibles se encontr�� que las mediciones de Di��xido de Azufre SO2, Mon��xido de Carbono CO se encuentran dentro del rango definido como el de menor impacto para la salud humana. De los datos del informe se puede concluir que la calidad del aire es buena en el 100% de las ��reas de influencia de las estaciones de tratamiento de crudo. Seg��n los informes de higiene industrial el 34% de las instalaciones presenta concentraciones de Sulfuro de Hidr��geno (H2S) en el l��mite permisible para exposiciones cr��nicas en un promedio ponderado de tiempo (TLV-TWA) y el l��mite permisible para exposiciones agudas en un l��mite de exposici��n a corto plazo (TLV-STEL). Solo el 37% de los trabajadores objeto de este estudio percibe el riesgo por la exposici��n a factores de riesgo qu��micos y son claramente consientes que se encuentran expuestos a estos riesgos por la manipulaci��n de productos qu��micos y exposici��n a sustancias qu��micas producto de sus actividades rutinarias, el 73% no percibe el riesgo de exposici��n por su actividad laboral. Se recomienda que la compa����a fortalezca su esquema de vigilancia para generar alternativas que eleven los niveles de consciencia del riesgo del trabajador. Los factores de riesgo ambiental y ocupacional, de los gases y vapores generados se deben al proceso de tratamiento de crudo, est��n mutuamente relacionados dado que al generarse una emisi��n y/o escape no controlado como consecuencia se tiene una afectaci��n directa al medio ambiente y a los trabajadores.

Inducible hydrogen sulfide synthesis in chondrocytes and mesenchymal progenitor cells: is H2S a novel cytoprotective mediator in the inflamed joint?

Hydrogen sulfide (H(2)S) has recently been proposed as an endogenous mediator of inflammation and is present in human synovial fluid. This study determined whether primary human articular chondrocytes (HACs) and mesenchymal progenitor cells (MPCs) could synthesize H(2)S in response to pro-inflammatory cytokines relevant to human arthropathies, and to determine the cellular responses to endogenous and pharmacological H(2)S. HACs and MPCs were exposed to IL-1��, IL-6, TNF-�� and lipopolysaccharide (LPS). The expression and enzymatic activity of the H(2)S synthesizing enzymes cystathionine-��-synthase (CBS) and cystathionine-��-lyase (CSE) were determined by Western blot and zinc-trap spectrophotometry, respectively. Cellular oxidative stress was induced by H(2)O(2), the peroxynitrite donor SIN-1 and 4-hydroxynonenal (4-HNE). Cell death was assessed by 3-(4,5-dimethyl-2-yl)-2,5-diphenyltetrazolium bromide (MTT) and lactate dehydrogenase (LDH) assays. Mitochondrial membrane potential (DCm) was determined in situ by flow cytometry. Endogenous H(2) S synthesis was inhibited by siRNA-mediated knockdown of CSE and CBS and pharmacological inhibitors D,L-propargylglycine and aminoxyacetate, respectively. Exogenous H(2)S was generated using GYY4137. Under basal conditions HACs and MPCs expressed CBS and CSE and synthesized H(2)S in a CBS-dependent manner, whereas CSE expression and activity was induced by treatment of cells with IL-1��, TNF-��, IL-6 or LPS. Oxidative stress-induced cell death was significantly inhibited by GYY4137 treatment but increased by pharmacological inhibition of H(2)S synthesis or by CBS/CSE-siRNA treatment. These data suggest CSE is an inducible source of H(2)S in cultured HACs and MPCs. H(2)S may represent a novel endogenous mechanism of cytoprotection in the inflamed joint, suggesting a potential opportunity for therapeutic intervention.

Key bioactive reaction products of the NO/H2S interaction are S/N-hybrid species, polysulfides, and nitroxyl

Experimental evidence suggests that nitric oxide (NO) and hydrogen sulfide (H2S) signaling pathways are intimately intertwined, with mutual attenuation or potentiation of biological responses in the cardiovascular system and elsewhere. The chemical basis of this interaction is elusive. Moreover, polysulfides recently emerged as potential mediators of H2S/sulfide signaling, but their biosynthesis and relationship to NO remain enigmatic. We sought to characterize the nature, chemical biology, and bioactivity of key reaction products formed in the NO/sulfide system. At physiological pH, we find that NO and sulfide form a network of cascading chemical reactions that generate radical intermediates as well as anionic and uncharged solutes, with accumulation of three major products: nitrosopersulfide (SSNO���), polysulfides, and dinitrososulfite N-nitrosohydroxylamine-N-sulfonate (SULFI/NO), each with a distinct chemical biology and in vitro and in vivo bioactivity. SSNO��� is resistant to thiols and cyanolysis, efficiently donates both sulfane sulfur and NO, and potently lowers blood pressure. Polysulfides are both intermediates and products of SSNO��� synthesis/decomposition, and they also decrease blood pressure and enhance arterial compliance. SULFI/NO is a weak combined NO/nitroxyl donor that releases mainly N2O on decomposition; although it affects blood pressure only mildly, it markedly increases cardiac contractility, and formation of its precursor sulfite likely contributes to NO scavenging. Our results unveil an unexpectedly rich network of coupled chemical reactions between NO and H2S/sulfide, suggesting that the bioactivity of either transmitter is governed by concomitant formation of polysulfides and anionic S/N-hybrid species. This conceptual framework would seem to offer ample opportunities for the modulation of fundamental biological processes governed by redox switching and sulfur trafficking.

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Group exhibition curated by Plastique Fantastique

Estudo dos compostos vol��teis de algumas esp��cies de eucalipto atrav��s do uso de microextra����o em fase s��lida no modo headspace (HS-SPME)

Neste trabalho utilizou-se a t��cnica de HS-SPME/GC/ITMS para o estudo qualitativo dos compostos vol��teis (VOC) emitidos pelas folhas de tr��s esp��cies de Eucalyptus (E.): E. citriodora, E. dunnii e E. saligna tanto em laborat��rio como in situ, al��m do estudo da rela����o entre folhas de eucalipto e r��s Litoria ewingi. Para este fim, foram desenvolvidos m��todos an��liticos. Os compostos tentativamente como (E,E)-a-farseno, (E)-4,8-dimetil-1,3,7-nonatrieno (DMNT),(E,E)-4,8,12-trimetil-1,3,7,11-tridecatetraeno (TMTT),B-cariofileno,a-cariofileno, gerrmacreno D e (E,E,E)-3,7,11,15-tetrametil-1,3,6,10,14-hexadecapentaeno (TMHP) foram encontrados no headspace de folhas picadas de eucalipto, sendo que os tr��s primeiros tamb��m foram nas emiss��es ��reas de E. saligna in situ, n��o tendo sido encontrados nos ��leos vol��teis das mesmas ��rvores, obtidos por hidrodestila����o. Nas amostragens in situ, foram observados dois tipos de perfis circadianos nas emiss��es vol��teis, incluindo compostos como cis-, trans-��xido de rosa, trans-B-ocimeno, citronelal, citronelol, entre outros. O comportamento dos compostos citados sugere que os mesmos sejam semioqu��micos. Os resultados obtidos com HS-SPME (PDMS/DVB) mostraram que esta �� uma ferramenta anal��tica relativamente simples, que preserva a vida devido ao seu car��ter n��o invasivo, de m��nima pertuba����o do sistema vivo sob amostragem e que, devido a sua rapidez (1 min), permite o acompanhamento de altera����oes r��pidas provocadas por processos end��genos e/ou ex��genos nos seres vivos. O monitoramento da emiss��o de vol��teis de folhas in situ durante 8 a 10 h por v��rios dias consecutivos, e a extra����o dos vol��teis de r��s vivas sob estresse, submetidas a diferentes condi����es de dieta e meio ambiente, exemplificam o potencial desta t��cnica, que abre novos horizontes na investiga����o de vol��teis de seres vivos.

Influ��ncia da temperatura e da presen��a de H2S no comportamento mec��nico e eletroqu��mico do a��o API 5CT grau P110 em ��gua do mar sint��tica

o presente trabalho teve por objetivo estudar o comportamento de um a��o de alta resist��ncia e baixa liga (com amostras de composi����o aproximada de 0,4% C, 0,6% Cr e 0,4% Mo), da classe API scr PIlO, utilizado na perfura����o de petr��leo offshore, frente a processos de fragiliza����o causados pelo meio. ��gua do mar sint��tica foi utilizada como meio, com intuito de padronizar, em laborat��rio, as condi����es a que o material fica submetido na pr��tica. Buscou-se avaliar e comparar o comportamento mec��nico do material pela modifica����o dos par��metros: temperatura, potencial aplicado ao material, e o efeito da presen��a ou aus��ncia de H2S na solu����o. Para isso, foram realizados ensaios de tra����o pelo m��todo de baixa taxa de deforma����o (da ordem de 10-6S-I), obtendo-se as curvas tens��o x deforma����o nas diferentes situa����es ensaiadas, comparadas com as obtidas em ��leo mineral. An��lises fratogr��ficas tamb��m foram utilizadas como forma de caracterizar os processos de fragiliza����o. Al��m disso, estudou-se o comportamento eletroqu��mico do material nas diferentes condi����es atrav��s de ensaios de polariza����o potenciost��ticos. Com isso, pode-se determinar quais as condi����es mais danosas e de maior risco para a utiliza����o do material e em quais delas o seu uso �� seguro. O a��o estudado apresentou-se suscept��vel a processos de fragiliza����o e todos os par��metros analisados mostraram-se importantes no estudo desses processos.

Evaluation of the zinox and zeolite materials as adsorbents to remove H2S from natural gas

MELO, Dulce Maria de Ara��jo et al. Evaluation of the Zinox and Zeolite materials as adsorbents to remove H2S from natural gas. Colloids and Surfaces. A, Physicochemical and Engineering Aspects, Estados Unidos, v. 272, p. 32-36, 2006.

Avalia����o da dolomita funcionalizada para remo����o de H2S em g��s natural

The natural gas is an alternative source of energy which is found underground in porous and permeable rocks and being associated or not to the oil. Its basic composition includes methane, other hydrocarbon and compounds such as carbon dioxide, nitrogen, sulphidric gas, mercaptans, water and solid particles. In this work, the dolomite mineral, a double carbonate of calcium and magnesium whose the chemical formula is CaMg(CO3)2, was evaluated as adsorbent material. The material was characterized by granulometric analysis, X-ray fluorescence, X-ray diffraction, thermogravimetric analysis, differential thermal analysis, specific surface area, porosity, scanning electronic microscopy and infrared spectroscopy. Then the material was functionalized with diethanolamine (dolomite+diethanolamine) and diisopropylamine (dolomite+diisopropylamine). The results indicated that the adsorbents presented appropriate physiochemical characteristics for H2S adsorption. The adsorption tests were accomplished in a system coupled to a gas chromatograph and the H2S monitoring in the output of the system was accomplished by a pulsed flame photometric detector (PFPD). The adsorbents presented a significant adsorption capacity. Among the analyzed adsorbents, the dolomite+diethanolamine presented the best capacity of adsorption. The breakthrough curves obtained proved the efficiency of this process

Avalia����o de sete fam��lias S2 prol��ficas de minimilho para a produ����o de h��bridos

Sete fam��lias S2 de minimilho foram cruzadas entre si em esquema dial��lico completo. Os h��bridos simples obtidos foram avaliados na Esta����o Experimental de S��o Manuel, da Faculdade de Ci��ncias Agr��rias da Universidade de S��o Paulo (UNESP-Botucatu). O experimento foi delineado em blocos casualizados com tr��s repeti����es. As parcelas consistiram de fileiras de 5 m espa��adas entre si por 0,90 m, com 50 plantas cada uma. Avaliaram-se as seguintes caracter��sticas: n��mero de espigas por parcela (NE), massa de espigas com palha (MECP) e sem palha (MESP), comprimento de espigas com palha (CECP) e sem palha (CESP), di��metro de espigas com palha (DECP) e sem palha (DESP), altura da planta (AP) e da espiga (AE). Estimaram-se os efeitos da capacidade geral e espec��fica de combina����o das fam��lias pelo m��todo 4, modelo estat��stico 1, proposto por Griffing. Houve predomin��ncia dos efeitos g��nicos aditivos para a massa de espigas com palha e sem palha. Entretanto, para o comprimento de espigas sem palha, di��metro de espigas com palha e sem palha, altura de planta e altura de espigas, os efeitos g��nicos aditivos e n��o aditivos foram equivalentes. Pelas estimativas das capacidades combinat��rias para o n��mero de espigas por parcela, massa de espigas com palha e sem palha, a fam��lia 27 �� a indicada para obter gen��tipos superiores.

Avalia����o e modelagem da absor����o de H2S do g��s natural em coluna de leito estagnado

Natural gas, although basically composed by light hydrocarbons, also presents contaminant gases in its composition, such as CO2 (carbon dioxide) and H2S (hydrogen sulfide). The H2S, which commonly occurs in oil and gas exploration and production activities, causes damages in oil and natural gas pipelines. Consequently, the removal of hydrogen sulfide gas will result in an important reduction in operating costs. Also, it is essential to consider the better quality of the oil to be processed in the refinery, thus resulting in benefits in economic, environmental and social areas. All this facts demonstrate the need for the development and improvement in hydrogen sulfide scavengers. Currently, the oil industry uses several processes for hydrogen sulfide removal from natural gas. However, these processes produce amine derivatives which can cause damage in distillation towers, can cause clogging of pipelines by formation of insoluble precipitates, and also produce residues with great environmental impact. Therefore, it is of great importance the obtaining of a stable system, in inorganic or organic reaction media, able to remove hydrogen sulfide without formation of by-products that can affect the quality and cost of natural gas processing, transport, and distribution steps. Seeking the study, evaluation and modeling of mass transfer and kinetics of hydrogen removal, in this study it was used an absorption column packed with Raschig rings, where the natural gas, with H2S as contaminant, passed through an aqueous solution of inorganic compounds as stagnant liquid, being this contaminant gas absorbed by the liquid phase. This absorption column was coupled with a H2S detection system, with interface with a computer. The data and the model equations were solved by the least squares method, modified by Levemberg-Marquardt. In this study, in addition to the water, it were used the following solutions: sodium hydroxide, potassium permanganate, ferric chloride, copper sulfate, zinc chloride, potassium chromate, and manganese sulfate, all at low concentrations (��10 ppm). These solutions were used looking for the evaluation of the interference between absorption physical and chemical parameters, or even to get a better mass transfer coefficient, as in mixing reactors and absorption columns operating in counterflow. In this context, the evaluation of H2S removal arises as a valuable procedure for the treatment of natural gas and destination of process by-products. The study of the obtained absorption curves makes possible to determine the mass transfer predominant stage in the involved processes, the mass transfer volumetric coefficients, and the equilibrium concentrations. It was also performed a kinetic study. The obtained results showed that the H2S removal kinetics is greater for NaOH. Considering that the study was performed at low concentrations of chemical reagents, it was possible to check the effect of secondary reactions in the other chemicals, especially in the case of KMnO4, which shows that your by-product, MnO2, acts in H2S absorption process. In addition, CuSO4 and FeCl3 also demonstrated to have good efficiency in H2S removal

Changes of metabolic and inflammatory markers in HIV infection: glucose, lipids, serum Hs-CRP and myeloperoxidase

Objective: HIV infection is exacerbated through additional pro-atherogenic mechanisms related to the processes of immune activation, inflammation, coagulation, and the modification of lipoproteins (e.g., particles of high density lipoprotein), contributing to increased cardiovascular risk. The aim of this study was to analyze the serum concentrations of myeloperoxidase (MPO) and other laboratory parameters in HIV-infected patients treated or not with antiretroviral drugs compared to non-infected individuals.Materials/Methods: The study included 154 volunteers: 47 non-infected individuals (control group - CON), 27 infected and untreated individuals (NTARv group) and 80 treated individuals (TARV group). We analyzed the counts of CD4+ lymphocytes and the viral load of the infected patients, along with the blood count, fasting glucose, total serum cholesterol (CHOL), HDL cholesterol, LDL cholesterol, triglycerides, MPO and high-sensitivity C-reactive protein (CRP) of all study participants.Results: There were significant increases in glucose, CHOL, LDL cholesterol, and triglycerides in the TARV group and significant reductions in the levels of HDL cholesterol for the TARV and NTARV groups. Significantly elevated levels of Hs-CRP were observed only in the TARV group, while levels of MPO were significantly higher in the TARV and NTARV groups compared to the control group. A correlation of MPO with Hs-CRP (r = 0.21, p = 0.032) was observed for HIV-infected patients, but MPO did not correlate significantly with the other analyzed parameters.Conclusions: The investigation of early biomarkers for cardiovascular risk evaluation, such as MPO, contributes to the clinical monitoring of HIV-infected individuals. The serum levels of MPO correlated with Hs-CRP and were high in HIV-infected individuals, indicating a possible predictor of cardiovascular events in these patients. (c) 2012 Elsevier B.V. All rights reserved.

Estudo da mistura comercial dolomita-quartzo, dopada com Hg(I), Cd(II) e Cr(III), para adsor����o de H2S

The present work was to carry out a study on the adsorption of hydrogen sulfide (H2S) in arrays synthesized from a commercial clay mineral formed by a mixture of dolomite and quartz. To produce the ion exchange matrix were made using aqueous solutions of salts of cobalt II chloride hexahydrate (CoCl2.6H2O) II cadmium nitrate tetrahydrate (Cd (NO3)2.4H2O) I mercuric chloride (HgCl) nitrate and chromium III pentahydrate (Cr (NO3)3.5H2O). The arrays were subjected to hydrogen sulphide gas passage for one hour. To check the amount of gas adsorbed was used gravimetric process. The best result was in the adsorption matrix doped with cadmium and the solution retained for a longer time than the largest amount of H2S was the cobalt matrix. The matrix unmodified exhibited poor adsorption capacity. The characterization of the matrices were used XRD, XRF and IV. Mother with cadmium showed a high capacity in ion exchange, because the percentage of cadmium increased from 0% to 81.38% by replacing atoms of calcium and silicon which increased from 96.54% to 17.56% and 15, 72% to 0.32%, respectively, but also the best performance in adsorption of H2S adsorbing 11.89507 mg per gram of matrix

Adsor����o dos gases NH3, NO e H2S em fosfato de vanadila, hidrogeno fosfato de vanadila e fosfatos de vanadila dopados por Al, Co, Mn e Cr

In this work were synthesized the materials called vanadyl phosphate, hydrogen vanadyl phosphate and vanadyl phosphate doped by transition metals with the aim in adsorption the following compounds: ammonia, hydrogen sulfide and nitrogen oxide. To characterize the starting compounds was used DRX, FTIR, FRX and TG analysis. After the characterization of substrates, proceeded de adsorption of NH3 and H2S gases in reactor, passing the gases with continuous flow for 30 min and room temperature. Gravimetric data indicate that the matrices of higher performance in adsorption of ammonia was those doped by aluminum and manganese, obtaining results of 216,77 mgNH3/g and 200,40 mgNH3/g of matrix, respectively. The matrice of higher performance in adsorption of hydrogen sulfide was that doped by manganese, obtaining results of 86,94 mgH2S/g of matrix. The synthesis of substrates VOPO4.2H2O and MnVOPO4.2H2O with nitrogen oxide was made in solution, aiming the final products VOPO4.G.nH2O and MnVOPO4.G.nH2O (G = NO and n = number of water molecules). The thermo analytical behavior and the infrared spectroscopy are indicative of formation of VOPO4.2,5NO.3H2O compound. Results of scanning electron microscopy (SEM) and Energy dispersive spectroscopy (EDS) of materials vanadyl phosphate and vanadyl phosphate modified after reaction in solid state or in solution with the gases show morphology changes in substrates, beyond the formation of orthorhombic sulfur crystals over their respective hosts when these adsorb hydrogen sulfide