Influência da vermiculita expandida na formulação de pastas leves para evitar a migração de gás em cimentação de poços petrolíferos

The gas migration during the cementing of wells is one of the main problems of oil wells engineering. Its occurrence can cause severe problems since shortly to loss of control of the well after cementation. Recently, 20/04/2010 In an accident of major proportions in the Gulf of Mexico, among other factors, faulty cementing operation provided the gas migration, causing the accident, in which 11 people died and 17 were injured occurred. Besides the serious consequences that can be caused by gas migration, remediation of the problem, which is made by injecting cement in damaged areas, usually involves additional costs and is not always effective. Therefore, preventing gas migration to be preferred. Some methods are used to prevent the migration of the pressurized gas as the annular space, application of pressure pulses, reducing the height of the cement column compressible cement pastes of low permeability, pastes and to control free filtered water, and binders of thixotropic cement expandable and flexible. Thus, the cement pastes used to prevent gas migration must meet the maximum these methods. Thus, this study aimed to formulate a cement paste to prevent gas migration, using the expanded vermiculite, and evaluate the behavior of the folder trials necessary for use in oil wells. Free water content, rheological properties, compressive strength, loss of liquid phase sedimentation of solids, specific weight, thickening time and gas migration: The following tests were performed. The results show that meets the specifications paste formulated for use in oil wells and the use of expanded vermiculite contribute to the absorption of free water, thixotropy and low density. The absorption of free water is proven to result in zero percentage test free water content, thixotropy is observed with the high value of the initial gel strength (Gi) in testing rheological properties and low density is proven in test weight specific

Nova técnica para obtenção de fraturas com altíssima condutividade em poços de petróleo

Increase hydrocarbons production is the main goal of the oilwell industry worldwide. Hydraulic fracturing is often applied to achieve this goal due to a combination of attractive aspects including easiness and low operational costs associated with fast and highly economical response. Conventional fracturing usually involves high-flowing high-pressure pumping of a viscous fluid responsible for opening the fracture in the hydrocarbon producing rock. The thickness of the fracture should be enough to assure the penetration of the particles of a solid proppant into the rock. The proppant is driven into the target formation by a carrier fluid. After pumping, all fluids are filtered through the faces of the fracture and penetrate the rock. The proppant remains in the fracture holding it open and assuring high hydraulic conductivity. The present study proposes a different approach for hydraulic fracturing. Fractures with infinity conductivity are formed and used to further improve the production of highly permeable formations as well as to produce long fractures in naturally fractured formations. Naturally open fractures with infinite conductivity are usually encountered. They can be observed in rock outcrops and core plugs, or noticed by the total loss of circulation during drilling (even with low density fluids), image profiles, pumping tests (Mini-Frac and Mini Fall Off), and injection tests below fracturing pressure, whose flow is higher than expected for radial Darcian ones. Naturally occurring fractures are kept open by randomly shaped and placed supporting points, able to hold the faces of the fracture separate even under typical closing pressures. The approach presented herein generates infinite conductivity canal held open by artificially created parallel supporting areas positioned both horizontally and vertically. The size of these areas is designed to hold the permeable zones open supported by the impermeable areas. The England & Green equation was used to theoretically prove that the fracture can be held open by such artificially created set of horizontal parallel supporting areas. To assess the benefits of fractures characterized by infinite conductivity, an overall comparison with finite conductivity fractures was carried out using a series of parameters including fracture pressure loss and dimensionless conductivity as a function of flow production, FOI folds of increase, flow production and cumulative production as a function of time, and finally plots of net present value and productivity index

Novos sistemas de liberação de fármacos à base de xilana

The aim of this work was to perform the extraction and characterization of xylan from corn cobs and prepare xylan-based microcapsules. For that purpose, an alkaline extraction of xylan was carried out followed by the polymer characterization regarding its technological properties, such as angle of repose, Hausner factor, density, compressibility and compactability. Also, a low-cost and rapid analytical procedure to identify xylan by means of infrared spectroscopy was studied. Xylan was characterized as a yellowish fine powder with low density and poor flow properties. After the extraction and characterization of the polymer, xylan-based microcapsules were prepared by means of interfacial crosslinking polymerization and their characterization was performed in order to obtain gastroresistant multiparticulate systems. This work involved the most suitable parameters of the preparation of microcapsules as well as the study of the process, scale-up methodology and biological analysis. Magnetic nanoparticles were used as a model system to be encapsulated by the xylan microcapsules. According to the results, xylan-based microcapsules were shown to be resistant to several conditions found along the gastrointestinal tract and they were able to avoid the early degradation of the magnetic nanoparticles

Impacto da variabilidade de peso no controle matebólico de pacientes transplantados cardíacos

Heart transplantation (HT) represents one of the greatest advances in medicine over the last decades. It is indicated for patients with severe heart disease unresponsive to clinical treatment and conventional surgery, poor short-term prognosis and a 1- year mortality rate over 40%. HT has improved survival worldwide (80% in the first year, 70% in five years and 60% in ten years). However, the procedure has been associated with weight change and increased risk of secondary conditions such as diabetes, hypertension, dyslipidemia and obesity due to immunosuppressive therapy following transplantation. The objective of this study was to determine the impact of weight change on the metabolic stability of HT patients. The study was retrospective with data collected from the records of 82 adult patients (83% male; average age 45.06±12.04 years) submitted to HT between October 1997 and December 2005 at a transplantation service in Ceará (Brazil). The selected outcome variables (biopathological profile, weight and body mass index―BMI) were related to biochemical and metabolic change. The results were expressed in terms of frequency, measures of central tendency, Student s t test and Pearson s correlation coefficients. The analysis showed that following HT the average global BMI increased from 23.77±3.68kg/m2 to 25.48±3.92kg/m2 in the first year and to 28.38±4.97kg/m2 in the fifth. Overweight/obese patients (BMI ≥ 25 kg/m2) had higher average levels of glucose, total cholesterol, low-density lipoprotein and triglycerides than patients with eutrophy/malnutrition (BMI < 25 kg/m2). In conclusion, overweight/obese patients were likely to present higher average levels of glucose, triglycerides, total cholesterol and fractions than patients with eutrophy/malnutrition, indicating a direct and significant relation between nutritional status and weight change in the metabolic profile of HT patients

Micropartículas poliméricas à base de xilana e Eudragit® S-100 contendo mesalazina visando à liberação cólon-específica

Colon-specific drug delivery systems have attracted increasing attention from the pharmaceutical industry due to their ability of treating intestinal bowel diseases (IBD), which represent a public health problem in several countries. In spite of being considered a quite effective molecule for the treatment of IBD, mesalazine (5-ASA) is rapidly absorbed in the upper gastrointestinal tract and its systemic absorption leads to risks of adverse effects. The aim of this work was to develop a microparticulate system based on xylan and Eudragit® S- 100 (ES100) for colon-specific delivery of 5-ASA and evaluate the interaction between the polymers present in the systems. Additionaly, the physicochemical and rheological properties of xylan were also evaluated. Initially, xylan was extracted from corn cobs and characterized regarding the yield and rheological properties. Afterwards, 10 formulations were prepared in different xylan and ES100 weight ratios by spray-drying the polymer solutions in 0.6N NaOH and phosphate buffer pH 7.4. In addition, 3 formulations consisting of xylan microcapsules were produced by interfacial cross-linking polymerization and coated by ES100 by means of spray-drying in different polymer weight ratios of xylan and ES100. The microparticles were characterized regarding yield, morphology, homogeneity, visual aspect, crystallinity and thermal behavior. The polymer interaction was investigated by infrared spectroscopy. The extracted xylan was presented as a very fine and yellowish powder, with mean particle size smaller than 40μm. Regarding the rheological properties of xylan, they demonstrated that this polymer has a poor flow, low density and high cohesiveness. The microparticles obtained were shown to be spherical and aggregates could not be observed. They were found to present amorphous structure and have a very high thermal stability. The yield varied according to the polymer ratios. Moreover, it was confirmed that the interaction between xylan and ES100 occurs only by means of physical aggregation

Melão amarelo (CAC) minimamente processado submetido a diferentes cortes e concentrações de cloreto de cálcio armazenado em atmosfera modificada passiva

The aim of this work was to evaluate the quality of yellow melon inodorus Valenciano Amarelo (CAC) fresh cut submitted to two cut types and with application postharvest of calcium chloride. After preparation cubes and slices melon were immersed in solution with different calcium chloride (CaCl2) concentrations for two minutes, afterwards they were conditioned in trays of expanded polystyrene (EPS), covered by plastic film of low density polyethylene (PEBD), stored in cold camera to 5 degrees C +/- 1 and analyzed for 8 days. They were evaluated pH, firmness, tritable acidity (AT), soluble solids (SS) sugar reducer and ratio. The pH values varied from 5.27 to 5.68. The sugars reducers content and the ratio were superior in the slices compared to the cubes. The melon slices maintained larger firmness values compared to the cubes and in general there was reduction in the values of this parameter along the storage period for all treatments. Concentrations of 1.0 and 1.5% of CaCl2, result in larger values of firmness. The storage temperature and modified passive atmosphere they contributed to quality maintenance of MP melon. Concentrations of up to 1.0% of CaCl2 they could be recommended to maintain the melon quality MP melon yellow inodorus (CAC).

Determinação dos intervalos de referência para lipídios, lipoproteínas e apolipoproteínas no estado do Rio Grande do Norte

The lipid profile is a group of lab tests that include triglycerides, total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C) and low-density lipoprotein cholesterol (LDL-C). However, serum non-HDL-C, Apo A-I and Apo B levels, as well as the lipids ratios (TC/HDL-C, LDL-C/HDL-C and Apo B/Apo A-I), have been described as better predictors of cardiovascular diseases. Reference intervals are tools often used to help the evaluation of the people s health state. These days, Brazilian studies still use the reference intervals of lipids and lipoproteins from other countries, ignoring differences between the populations. Therefore, this study aimed to establish reference intervals for lipids, lipoproteins and apolipoproteins in adults of Rio Grande do Norte/Brazil. Healthy individuals (96 men and 283 women) between 18 and 59years old formed the reference sample group. The samples were collected after fasting 12 to 14 hours. Information on lifestyle and dietary habits of the participants were obtained through questionnaire. The serum glucose level and renal and liver activity were evaluated by laboratory testing. The results of lipid profile were analyzed according to sex, age and mesoregion of Rio Grande do Norte, with significance level of 5% (p < 0,05). The lower and upper reference limits were identified by the 2.5 percentile and 97.5 percentile, respectively, and assurance intervals of 90% was calculated for each of these limits. Among the determinants of lipid profile analyzed, only a few significant differences were observed according to sex, but in terms of age, the groups of smaller and older ages were most likely different. When evaluated by region, the means of West region shown the most significant variations. Not many studies were useful to compare the reference intervals determined in this study. Thus, it becomes necessary to carry out similar studies in other regions of Brazil and of the world given the clinical importance of reference intervals

Estudo de pré-formulação para dose fixa combinada dos tuberculostáticos rifampicina, isoniazida, pirazinamida e etambutol (4 em 1)

According to the global framework regarding new cases of tuberculosis, Brazil appears at the 18th place. Thus, the Ministry of Health has defined this disease as a priority in the governmental policies. As a consequence, studies concerning treatment and prevention have increased. Fixed-dose combination formulations (FDC) are recognized as beneficial and are recommended by WHO, but they present instability and loss on rifampicin bioavailability. The main purpose of this work was to carry out a pre-formulation study with the schedule 1 tuberculosis treatment drugs: rifampicin, isoniazid, pyrazinamide and ethambutol and pharmaceutical excipients (lactose, cellulose, magnesium stearate and talc), in order to develop an FDC product (150 mg of rifampicin + 75 mg of isoniazid + 400 mg of pyrazinamide + 250 mg of ethambutol). The studies consisted of the determination of particle size and distribution (Ferret s diameter) and shape through optical microscopy, as well as rheological and technological properties (bulk and tapped densities, Hausner Factor, Carr s Index, repose angle and flux rate) and interactions among drugs and drug excipient through thermal analysis (DSC, DTA, TG and your derivate). The results showed that, except isoniazid, the other drugs presented poor rheological properties, determined by the physical characteristics of the particles: small size and rod like particles shape for rifampicin; rectangular shape for pyrazinamide and ethambutol, beyond its low density. The 4 drug mixture also not presented flowability, particularly that one containing drug quantity indicated for the formulation of FDC products. In this mixture, isoniazid, that has the best flowability, was added in a lower concentration. The addition of microcrystalline cellulose, magnesium stearate and talc to the drug mixtures improved flowability properties. In DSC analysis probable interactions among drugs were found, supporting the hypothesis of ethambutol and pyrazinamide catalysis of the rifampicin-isoniazid reaction resulting in 3- formylrifamycin isonicotinyl hydrazone (HYD) as a degradation product. In the mixtures containing lactose Supertab® DSC curves evidenced incompatibility among drugs and excipient. In the DSC curves of mixtures containing cellulose MC101®, magnesium stearate and talc, no alterations were observed comparing to the drug profiles. The TG/DTG of the binary and ternary mixtures curves showed different thermogravimetrics profiles relating that observed to the drug isolated, with the thermal decomposition early supporting the evidences of incompatibilities showed in the DSC and DTA curves

Efeito do ácido alfa-lipóico sobre biomarcadores de estresse oxidativo, inflamação e fatores de risco cardiovascular em hipertensos

Alpha-lipoic acid (ALA) is a potent antioxidant with favourable anti-inflammatory, metabolic and endothelial effects, and has been widely investigated due to its potential against cardiovascular risk factors. This study aimed to evaluate the effect of oral ALA supplementation on oxidative stress biomarkers, inflammation and cardiovascular risk factors in patients with hypertension. This is a double-blind placebo-controlled randomized clinical trial, where the intervention was evaluated prospectively comparing results in both groups. The sample consisted of 64 hypertensive patients who were randomly distributed into ALA group (n = 32), receiving 600 mg / day ALA for twelve weeks and control group (n = 32), receiving placebo for the same period. The following parameters were evaluated before and after intervention: lipid peroxidation, content of reduced glutathione (GSH), enzymatic activities of glutathione peroxidase (GPx) and superoxide dismustase, ultrasensitive C-reactive protein (hs-CRP), triglycerides, total cholesterol and fractions, fasting glucose and anthropometric indicators. There was a statistically significant reduction (p <0.05) in serum concentrations of total cholesterol, very low density lipoprotein (VLDL), high density lipoprotein (HDL), triglycerides and blood glucose. There was a reduction in body weight and waist, abdominal and hip circumferences in the group that received ALA. In addition, there was a statistically significant increase (p <0.05) in the contents of reduced glutathione (GSH) and glutathione peroxidase (GPx) in the group receiving ALA. Oral administration of ALA appears to be a valuable adjuvant therapy, which may contribute to decrease the damage caused by oxidative stress and other risk factors associated with the atherosclerotic process

Estudo de competição inter e intraespecífica envolvendo Glycine max (L. ) Merril e Cyperus rotundus (L.), em condições de casa de vegetação

O presente experimento teve por objetivo estudar os efeitos da competição inter e intraespecífica envolvendo Glycine max (L.) Merril e Cyperus rotundus L. sobre as características das plantas e acúmulos de N, P, K, Ca e Mg pelas espécies envolvidas. Para tanto, estipulou-se um tratamento em que se desenvolveram três plantas de Glycine max e outro em que se desenvolveram 3 tubérculos de Cyperus rotundus por vaso. Para estudar os efeitos da competição intraespecífica, em dois outros tratamentos dobraram-se as populações por vaso. No estudo da competição interespecífica permitiu-se o desenvolvimento de três plantas de Glycine max e de três tubérculos de Cyperus rotundus num mesmo vaso. de uma maneira geral, pôde-se observar que principalmente devido às diferenças no hábito de crescimento das duas espécies, a expressão da competição inter e intraespecífica, em cada uma delas, assume aspectos distintos. No caso de Cyperus rotundus, o efeito do dobro da densidade pôde ser compensado, em parte, pela maior produção de manifestações epígeas e de tubérculos, aliados ao maior desenvolvimento dos tubérculos na menor densidade de plantio. No caso da competição interespecífica, os resultados sugerem um efeito decisivo do sombreamento de Leguminosae sobre o comportamento da Cyperaceae. Os padrões de efeitos da competição pelos nutrientes foi determinado também pelas diferenças no recrutamento dos elementos do solo pelas espécies envolvidas.

Bases para a padronização do teste de germinação em três espécies de Solanum L.

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Perda de calor por evaporação cutânea associada às características morfológicas do pelame de cabras leiteiras criadas em ambiente tropical

A perda de calor por evaporação cutânea e as características morfológicas do pelame (espessura da capa, comprimento médio dos pêlos, número de pêlos por unidade de área e diâmetro médio dos pêlos) foram avaliadas em 254 cabras das raças Saanen, Alpina e mestiças ½ Boer ½ Saanen. Utilizou-se uma cápsula ventilada para medir a evaporação cutânea, determinada em três regiões do corpo (próximo ao pescoço, meio do flanco e quarto traseiro), enquanto as características morfológicas do pelame foram avaliadas a partir de amostras de pêlos, tomadas 18 cm abaixo da coluna vertebral, exceto a espessura da capa, que foi medida in situ. Os resultados indicaram que os animais apresentam pelame pouco denso, formado por pêlos finos e compridos. Animais mestiços (½ Bôer ½ Saanen) apresentaram taxas de evaporação cutânea mais elevadas que os puros das raças Saanen e Alpina.

Avaliação de diferentes tipos de atmosferas modificadas na vida útil de carambolas minimamente processadas

Este trabalho teve por objetivo a avaliação da vida útil potencial de carambolas cv. Golden Star, minimamente processadas, armazenadas em diferentes tipos de embalagens plásticas, para a concepção da atmosfera modificada. Os frutos colhidos fisiologicamente maturos apresentaram coloração verde-amarelada, sólidos solúveis (SS) médios de 6,8 ºBrix e massa média de 185 g. Antes da aplicação dos tratamentos, os frutos foram selecionados, higienizados em solução de hipoclorito de sódio (NaOCl) a 100 mg. L-1, resfriados por 12 horas a 15 ± 0,5 °C, seccionados transversalmente, sendo então novamente higienizados em solução de NaOCl a 10 mg.L-1, por 3 minutos. em seguida, os pedaços em forma de estrelas foram acondicionados em bandejas rígidas de poliestireno, com capacidade para 250 g, e revestidas com os seguintes materiais: T1: filme plástico perfurado de polietileno de baixa densidade (PEBD), de 0,006 mm; T2: filme plástico poliolefínico com antiembassamento da Dupont® (AGF), de 0,015 mm; T3: filme plástico poliolefínico da Dupont® (HF), de 0,015 mm; T4: filme plástico de PEBD, de 60 µm; T5: filme plástico de PEBD, de 80 µm; T6: filme plástico de polipropileno (PP), de 22 µm, e T7: bandeja rígida de polietileno tereftalato (PET), com capacidade para 500 mL, com tampa do mesmo material. As embalagens foram então armazenadas em câmara frigorífica a 12 ± 0,5 °C e 90 ± 3% de U.R, por 18 dias. Observou-se que não houve diferença significativa quanto aos sólidos solúveis (SS) e acidez titulável (AT). O maior número de microrganismos e valor de pH foram observados nos frutos embalados nos filmes plásticos de PEBD de 0,006 mm, AGF e HF de 0,015 mm da Dupont®. Entretanto, os frutos acondicionados nas embalagens PET apresentaram o maior teor de ácido ascórbico. da mesma forma, somente nas embalagens PET é que se conseguiu modificação atmosférica eficiente do ponto de vista da manutenção dos atributos de qualidade durante o AR. Assim, esse tratamento proporcionou adequado controle microbiológico e manutenção das características de qualidade por 18 dias para as carambolas minimamente processadas.

Radiação gama e atmosfera modificada passiva na qualidade de goiabas 'Pedro Sato'

O objetivo deste trabalho foi avaliar o efeito da irradiação gama associada à atmosfera modificada passiva na qualidade pós-colheita de goiabas 'Pedro Sato', verificando suas características físico-químicas. Foram utilizadas goiabas provenientes da região de Vista Alegre do Alto-SP,Brasil. Após a colheita, as goiabas foram imediatamente transportadas ao Laboratório de Frutas e Hortaliças, pertencente ao Departamento de Gestão e Tecnologia Agroindustrial, da Faculdade de Ciências Agronômicas - UNESP - Câmpus de Botucatu-SP, onde foram armazenadas a 10ºC e 90-95%UR, em câmara frigorífica, por 28 dias. Os tratamentos foram: controle 1 (sem embalagem e sem irradiação); controle 2 (embalagem de poliestireno (PS) + polietileno de baixa densidade (PEBD) e sem irradiação); tratamento 1 (PS+PEBD e 0,2kGy); tratamento 2 (PS+PEBD e 0,6kGy), e tratamento 3 (PS+PEBD e 1,0kGy). As análises realizadas foram: firmeza, sólidos solúveis (SS), acidez titulável (AT) e índice de maturação. Foi utilizado o delineamento inteiramente casualizado, com esquema fatorial 5 x 5 (tratamento x tempo). Concluiu-se que as altas doses de irradiação promoveram efeito negativo nas características físico-químicas da goiaba 'Pedro Sato', e que apenas a menor dose utilizada (0,2kGy) associada à atmosfera modificada conservou frutos com maior qualidade e aceitabilidade, indicado por maiores índice de maturação e teor de sólidos solúveis obtidos.

Qualidade pós-colheita de mangas, não-refrigeradas, e submetidas ao controle da ação do etileno

O presente trabalho objetivou-se na caracterização físico-química de mangas cv. Tommy Atkins e Haden, submetidas ao controle da ação do etileno, através da exposição dos frutos à ação de adsorvedores de etileno. Os frutos colhidos em estádio de fisiologicamente maturos foram embalados em filmes de polietileno de baixa densidade (PEBD) de 0,006 mm de espessura, com ou sem o sachê de adsorção de etileno, e acondicionados em embalagens de papelão (0,65 x 0,52 m), sem o controle da temperatura e da umidade relativa (30 ± 3 ºC e 70 ± 5 % de U.R.). Os tratamentos ficaram constituídos dessa maneira: T1 - mangas cv. Tommy Atkins, com o sachê de adsorção; T2 - mangas cv. Tommy Atkins, sem o sachê de adsorção; T3- mangas cv. Haden com o sachê de adsorção, e T4 - mangas cv Haden sem o sachê de adsorção. As análises de firmeza de polpa, sólidos solúveis (SS), acidez titulável (AT), pH, ácido ascórbico e concentração de etileno foram realizadas na instalação do experimento (dia 0), e aos 7; 14; 21; 28 e 35 dias; e aos 35 dias foi realizado um teste de preferência. Ao final do experimento, observou-se que, em ambas as cultivares, a menor concentração de etileno nas embalagens, a maior firmeza de polpa, a maior contenção no avanço e na diminuição do SS e AT, respectivamente, bem como a melhor manutenção do conteúdo de ácido ascórbico foram detectadas nos frutos acondicionados em embalagens contendo o sachê de adsorção de etileno. Não foram detectadas variações significativas nos valores de pH. No teste de preferência, houve variação significativa, onde os frutos acondicionados sob ação do adsorvedor de etileno foram preferidos por parte dos julgadores.