Adição de resíduo cerâmico em pastas geopoliméricas para cimentação de poços de petróleo

The development of activities the of oil and gas sector have promoted the search for suitable materials for cementing oil wells. In the state of the Rio Grande do Norte, the integrity of the cement sheath tends to be impaired during steam injection, a procedure necessary to increase oil recovery in reservoirs with low-viscosity oil. The geopolymer is a material that can be used as alternative cement, since it has been used in the production of fire-resistant components, building structures, and for the control of toxic or radioactive residues. Geopolymers result from condensation polymer alkali aluminosilicates and silicates resulting three-dimensional polymeric structures. They are produced in a manner different from that of Portland cement, which is made an activating solution that is mixed with geopolymer precursor. Among the few works studied allowed us to conclude that the pastes prepared with metakaolin as precursor showed better performance of its properties. Several studies show the addition of waste clay as a means of reducing cost and improving end of the folder properties. On this basis, the goal is to study the influence of the addition of ceramic waste in geopolymer paste. To develop the study of rheology tests were carried out, filtered, thickening time, compressive strength, free water, specific gravity and permeability, according to the American Pretoleum Institute (API). The results for all formulations studied show that the folders have high mechanical strength to a light paste; low filtrate volume, absence of free water, very low permeability, slurry, consistent with a light paste, and thickening time low that can be corrected with the use of a retardant handle. For morphological characterization, microstructural, physical, chemical and thermal tests were carried out by XRD, MEV, DTA, TG, FTIR. In the trial of XRD, it was found that geopolymer is an amorphous material, with a peak of crystalline kaolinite. In tests of TG / DTA, revealed the presence of a significant event, which represents the mass loss related to water, and also observed the reduction of weight loss by increasing the concentration of ceramic waste. In the trial of MEV, we found a uniform matrix without the presence of other phases. In the trial of FT-IR, we observed the presence of the band related to water. From all results it was determined that the optimum concentration range of use is between 2.5 and 5% of waste ceramic

Aditivação de pastas geopoliméricas com tetraborato de sódio e látex não iônico para cimentação de Poços de Petróleo

The development of activities in the oil and gas sector has been promoting the search for materials more adequate to oilwell cementing operation. In the state of Rio Grande do Norte, the cement sheath integrity tend to fail during steam injection operation which is necessary to increase oil recovery in reservoir with heavy oil. Geopolymer is a material that can be used as alternative cement. It has been used in manufacturing of fireproof compounds, construction of structures and for controlling of toxic or radioactive waste. Latex is widely used in Portland cement slurries and its characteristic is the increase of compressive strength of cement slurries. Sodium Tetraborate is used in dental cement as a retarder. The addition of this additive aim to improve the geopolymeric slurries properties for oilwell cementing operation. The slurries studied are constituted of metakaolinite, potassium silicate, potassium hydroxide, non-ionic latex and sodium tetraborate. The properties evaluated were: viscosity, compressive strength, thickening time, density, fluid loss control, at ambient temperature (27 ºC) and at cement specification temperature. The tests were carried out in accordance to the practical recommendations of the norm API RP 10B. The slurries with sodium tetraborate did not change either their rheological properties or their mechanical properties or their density in relation the slurry with no additive. The increase of the concentration of sodium tetraborate increased the water loss at both temperatures studied. The best result obtained with the addition of sodium tetraborate was thickening time, which was tripled. The addition of latex in the slurries studied diminished their rheological properties and their density, however, at ambient temperature, it increased their compressive strength and it functioned as an accelerator. The increase of latex concentration increased the presence of water and then diminished the density of the slurries and increased the water loss. From the results obtained, it was concluded that sodium tetraborate and non-ionic latex are promising additives for geopolymer slurries to be used in oilwell cementing operation

Avaliação do potencial de formigas (Hymenoptera: formicidae) como vetores mecânicos de bactérias do gêneroSstaphylococcus no ambiente hospitalar.

In a hospital environment, these bacteria can be spread by insects such as ants, which are characterized by high adaptability to the urban environment. Staphylococcus is a leading cause of hospital infection. In Europe, Latin America, USA and Canada, the group of coagulase negative staphylococci (CoNS) is the second leading cause of these infections, according to SENTRY (antimicrobial surveillance program- EUA). In this study, we investigated the potential of ants (Hymenoptera: Formicidae) as vehicle mechanics of Staphylococcus bacteria in a public hospital, in Natal-RN. The ants were collected, day and night, from June 2007 to may 2008, in the following sectors: hospitals, laundry, kitchen, blood bank. The ants were identified according to the identification key of Bolton, 1997. For the analysis of staphylococci, the ants were incubated in broth Tryptic Soy Broth (TSB) for 24 hours at 35 º C and then incubated on Mannitol Salt Agar. The typical colonies of staphylococci incubated for 24 hours at 35 ° C in Tryptic Soy Agar for the characterization tests (Gram stain, catalase, susceptibility to bacitracin and free coagulase). The identification of CoNS was performed through biochemical tests: susceptibility to novobiocin, growth under anaerobic conditions, presence of urease, the ornithine decarboxylation and acid production from the sugars mannose, maltose, trehalose, mannitol and xylose. The antimicrobial susceptibility examined by disk-diffusion technique. The technique of Polymerase Chain Reaction was used to confirm the presence of mecA gene and the ability to produce biofilm was verified by testing in vitro using polystyrene inert surface, in samples of resistant staphylococci. Among 440 ants, 85 (19.1%) were carrying coagulase-negative staphylococci (CoNS) of the species Staphylococcus saprophyticus (17), Staphylococcus epidermidis (15), Staphylococcus xylosus (13), Staphylococcus hominis hominis (10), Staphylococcus lugdunensis (10), Staphylococcus warneri (6), Staphylococcus cohnii urealyticum (5), Staphylococcus haemolyticus (3), Staphylococcus simulans (3), Staphylococcus cohnii cohnii (2), and Staphylococcus capitis (1). No Staphylococcus aureus was found. Among the isolates, 30.58% showed resistance to erythromycin. Two samples of CoNS (2.35%), obtained from the ant Tapinoma melanocephalum collected in the post-surgical female ward, S. Hominis hominis and S. lugdunensis harbored the mecA gene and were resistant to multiple antibiotics, and the specie S. hominis hominis even showed to be a biofilm producer. This study proves that ants act as carriers of multidrug-resistant coagulase-negative Staphylococci and biofilm producers and points to the risk of the spreading of pathogenic microorganisms by this insect in the hospital environment

Antígenos da forma amastigota de Leishmania chagasi identificados por dupla varredura da biblioteca de cDNA

Control of human visceral leishmaniasis in endemic regions is hampered in part by the lack of knowledge with respect of the role reservoirs and vector. In addition, there is not yet an understanding of how non-symptomatic subclinical infection might influence the maintenance of infection in a particular locality. Of worrisome is the limited accessibility to medical care in places with emerging drug resistance. There is still no available protective vaccine either for humans or other reservoirs. Leishmania species are protozoa that express multiple antigens which are recognized by the vertebrate immune system. Since there is not one immunodominant epitope recognized by most hosts, strategies must be developed to optimize selection of antigens for prevention and immunodiagnosis. For this reason, we generated a cDNA library from the intracellular amastigote form of Leishmania chagasi, the causative agent of South American visceral leishmaniasis. We employed a two-step expression screen of the library to systematically identify T and T-dependent B cell antigens. The first step was aimed at identifying the largest possible number of clones producing an epitope-containing polypeptide with a pool of sera from Brazilians with documented visceral leishmaniasis. After removal of clones encoding heat shock proteins, positive clones underwent a second step screen for their ability to cause proliferation and IFN-γ responses of T cells from immune mice. Six unique clones were selected from the second screen for further analysis. The clones encoded part of the coding sequence of glutamine synthetase, transitional endoplasmic reticulum ATPase, elongation factor 1γ, kinesin K-39, repetitive protein A2, and a hypothetical conserved protein. Humans naturally infected with L. chagasi mounted both cellular and antibody responses to these protein Preparations containing multiple antigens may be optimal for immunodiagnosis and protective vaccines against Leishmania

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

Avaliação da atividade biológica de óleos essenciais sobre candida não albicans de origem clínica

Candidíase é um problema de importância crescente, devido o aumento do número de indivíduos imunocomprometidos e o surgimento de cepas resistentes aos antifúngicos convencionais. É de fundamental importância a busca por novos agentes antifúngicos mais eficazes, menos tóxicos, sendo os óleos essenciais (OEs) excelentes alternativas para esse propósito. Esse estudo investigou a atividade biológica do OE de Mentha spicata L. sobre Candida guilliermondii de origem anal e vaginal. Para tanto foram determinadas a Concentração Inibitória Mínima (CIM), Concentração Fungicida Mínima (CFM), cinética do crescimento das leveduras (Time-Kill), alterações micromorfológicas (técnica do microcultivo em câmara úmida) e investigação do mecanismo de ação antifúngico, utilizando o bioensaio do sorbitol. O OE de M. spicata foi obtido pelo processo de extração por destilação a vapor. Na análise fitoquímica desse óleo foi observada a presença de carvona com 84,32%, seguida pelo limoneno (13,70%) e traços de iso-dihidrocarvona (0,82%). Os resultados da análise da CIM variou entre 32 e 128 μg/mL. A CFM variou entre 64 e 1024 μg/mL. Na avaliação da ação de OE e da nistatina 100UI/mL, o antifúngico padrão apresentou o efeito fungicida a partir de 4 horas e para OE de M. spicata foi observado efeito fungistático na CIM, CIMX2 e CIMX4 frente às cepas avaliadas. O OE de M. spicata apresentou forte atividade antifúngica contra as cepas de C. guilliermondii, promovendo alterações micromorfológicas visíveis por microscopia óptica, nas concentrações testadas (CIM, CIMx2), resultado semelhante ao que se observou com a nistatina (100UI/mL). Na investigação do mecanismo de ação antifúngico foi constatado que houve alteração da CIM na presença de sorbitol, com elevação dos valores quatro vezes maior que a concentração inicial, o que indica que os componentes desse OE apresentam ação direta sobre a parede celular das leveduras. Conclui-se que o OE de Mentha spicata é um potencial agente terapêutico no tratamento de candidíase

Isolation and characterization of Flavobacterium columnare (Bernardet et al. 2002) from four tropical fish species in Brazil

Flavobacterium columnare é o agente etiológico da columnariose em peixes de água doce, ocasionando enfermidade na pele e nas brânquias, provocando freqüentemente um grande número de mortalidade. O objetivo deste estudo foi o isolamento e a caracterização de Flavobacterium columnare em peixes tropicais no Brasil. Piracanjuba (Brycon orbignyanus), pacu (Piaractus mesopotamicus), tambaqui (Colossoma macropomum) e cascudo (Hypostomus plecostomus) foram examinados externamente com relação a sinais característicos de columnariose, como manchas acinzentadas na cabeça, região dorsal e pedúnculo caudal dos peixes. A amostragem compreendeu a coleta de 50 exemplares de peixes, representando as quatro diferentes espécies escolhidas para este estudo. Amostras para o isolamento foram obtidas através de raspado com swab estéril das lesões e do rim dos peixes clinicamente diagnosticados como acometidos por columnarios e imediatamente semeados em meios de culturas artificiais (líquido e sólido) próprios para o estudo de Flavobacterium segundo Carlson e Pacha (1968). No meio líquido, houve o desenvolvimento de microrganismos que observados em gota pendente apresentaram a forma de bacilos finos, longos, móveis por deslizamento. Através da coloração de Gram, apresentaram morfologia de bacilos finos, Gram negativos, agrupados em colunas. em meio sólido, as colônias eram pequenas, cinza-amareladas, com borda em forma de raiz. No total, foram obtidos quatro isolamentos: 01 cepa de Brycon orbignyanus; 01 cepa de Piaractus mesopotamicus; 01 cepa de Colossoma macropomum; e 01 cepa de Hypostomus plecostomus. A caracterização bioquímica das amostras, como absorção do vermelho Congo, produção de flexirrubina, produção de H2S e redução do nitrato, sugere que os isolamentos poderiam ser classificados como Flavobacterium columnare.

Herança da resistência ao enfezamento em milho

Os objetivos deste trabalho foram determinar a herança da resistência ao complexo de enfezamento em milho e determinar as melhores fontes de resistência entre as linhagens estudadas. Foram realizadas as análises dialélica e médias de gerações em linhagens de milho. Para a análise dialélica, foram cruzadas 12 linhagens de milho, em dialélico parcial. Para análises de médias de gerações, foram cruzadas três linhagens resistentes e quatro suscetíveis, para a obtenção das gerações F1, F2, RCP R e RCP S. Os trabalhos foram conduzidos em Jaboticabal, SP. A incidência de enfezamento foi avaliada no estádio fenológico R3. Efeitos significativos quanto à capacidade geral de combinação e capacidade específica de combinação foram obtidos, o que indicou que, no controle do caráter enfezamentos, estão envolvidos tanto os efeitos aditivos quanto os de dominância. Análises de médias de gerações mostraram a presença de poucos genes envolvidos com o controle da resistência, com predominância de efeitos aditivos, o que permite a seleção de genótipos resistentes. As linhagens L02, L03 e L05 poderão ser utilizadas como fontes de resistência, em futuras combinações híbridas.

Identificação dos princípios ativos presentes no extrato etanólico de cereus jamacaru e avaliação em ratos dos possíveis efeitos tóxicos e/ou comportamentais da exposição prolongada

Conselho Nacional de Desenvolvimento Científico e Tecnológico

Micropartículas de poli (ácido lático-co-ácido glicólico) obtidas por spray drying para a liberação prolongada de metotrexato

Methotrexate (MTX) is a drug used in the chemotherapy of some kind of cancers, autoimmune diseases and non inflammatory resistant to corticosteroids uveits. However, the rapid plasmatic elimination limits its therapeutic success, which leads to administration of high doses to maintain the therapeutic levels in the target tissues, occurring potential side effects. The aim of this study was to obtain spray dried biodegradable poly-lactic acid co-glycolic acid (PLGA) microparticles containing MTX. Thus, suitable amounts of MTX and PLGA were dissolved in appropriate solvent system to obtain solutions at different ratios drug/polymer (10, 20, 30 and 50% m/m). The physicochemical characterizing included the quantitative analysis of the drug using a validate UV-VIS spectrophotometry method, scanning electron microscopy (SEM), infrared spectrophotometry (IR), thermal analyses and X-ray diffraction analysis. The in vitro release studies were carried out in a thermostatized phosphate buffer pH 7.4 (0.05 M KH2PO4) medium at 37°C ± 0.2 °C. The in vitro release date was subjected to different kinetics release models. The MTX-loaded PLGA microparticles showed a spherical shape with smooth surface and high level of entrapped drug. The encapsulation efficiency was greater then 80%. IR spectroscopy showed that there was no chemical bond between the compounds, suggesting just the possible occurrence of hydrogen bound interactions. The thermal analyses and X-ray diffraction analysis shown that MTX is homogeneously dispersed inside polymeric matrix, with a prevalent amorphous state or in a stable molecular dispersion. The in vitro release studies confirmed the sustained release for distinct MTX-loaded PLGA microparticles. The involved drug release mechanism was non Fickian diffusion, which was confirmed by Kornmeyer-Peppas kinetic model. The experimental results demonstrated that the MTX-loaded PLGA microparticles were successfully obtained by spray drying and its potential as prolonged drug release system.

Avaliação da atividade antimicrobiana de sistemas emulsionados contendo óleos naturais para o tratamento de infecções cutâneas

Natural oils have shown a scientific importance due to its pharmacological activity and renewable character. The copaiba (Copaifera langsdorffii) and Bullfrog (Rana catesbeiana Shaw) oils are used in folk medicine particularly because the anti-inflammatory and antimicrobial activities. Emulsion could be eligible systems to improve the palatability and fragrance, enhance the pharmacological activities and reduce the toxicological effects of these oils. The aim of this work was to investigate the antimicrobial activity of emulsions based on copaiba (resin-oil and essential-oil) and bullfrog oils against fungi and bacteria which cause skin diseases. Firstly, the essential oil was extracted from copaiba oil-resin and the oils were characterized by gas chromatography coupled to a mass spectrometry (GC-MS). Secondly, emulsion systems were produced. A microbiological screening test with all products was performed followed (the minimum inhibitory concentration, the bioautography method and the antibiofilm determination). Staphylococcus aureus, S. epidermidis, Pseudomonas aeruginosa, Candida albicans, C. parapsilosis, C. glabrata, C. krusei and C. tropicalis American Type Culture Collection (ATCC) and clinical samples were used. The emulsions based on copaiba oil-resin and essential oil improved the antimicrobial activity of the pure oils, especially against Staphylococcus e Candida resistant to azoles. The bullfrog oil emulsion and the pure bullfrog oil showed a lower effect on the microorganisms when compared to the copaiba samples. All the emulsions showed a significant antibiofilm activity by inhibiting the cell adhesion. Thus, it may be concluded that emulsions based on copaiba and bullfrog oils are promising candidates to treatment of fungal and bacterial skin infections

Preparação e caracterização de sistemas emulsionados contendo benznidazol

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior

Características genotípicas e fenotípicas de Candida Albicans isoladas da cavidade bucal de pacientes transplantados renais com ênfase na ação do extrato bruto de Eugenia uniflora em fatores de virulência

Candida albicans is a diploid yeast that in some circumstances may cause oral or oropharyngeal infections. The investigation of natural products is mandatory for the discovery of new targets for antifungal drugs development. This study aimed to determine the genotypes of 48 clinical isolates of C. albicans obtained from the oral cavity of kidney transplant patients from two distinct geographic regions of Brazil. In addition, we investigated three virulence factors in vitro: phospholipase activity, morphogenesis and the ability to evade from polymorphonuclear neutrophils. The expression of these virulence factors in vitro was also investigated in the presence of the crude extract of Eugenia uniflora. The genotype A was the most prevalent (30 isolates; 62.5%), followed by genotype C (15 isolates; 31.5%) and genotype B (3 isolates; 6.25%). When microsatellite technique with primer M13 was applied, 80% of the isolates from the South were placed within the same cluster. All Genotype C strains were grouped together within two different clusters. Genotype C was considered more resistant to PMNs attack than genotypes A and B. Strains isolated from the South of Brazil showed higher ability to combat PMNs phagocytosis. We found a high rate of genotype C strains isolated from the oral cavity of this group of patients. The crude extract of E. uniflora inhibited proper hypha formation and phagocytosis by PMNs, but had no significant effect on phospholipase activity. This study characterized oral C. albicans strains isolated from kidney transplant recipients and will contribute for the better understanding of the pathogenesis and alternative therapeutics for oral candidiasis

Instituições prevalecentes, tradição e persistência no extrativismo da cera de carnaúba em Limoeiro do Norte -CE

A presente pesquisa visa entender os fatores que explicam a manutenção dos aspectos artesanais no extrativismo da cera de carnaúba em Limoeiro do Norte. Justificamos a exploração desse tema pelo fascínio do autor pelo tema e por ser esse recurso ainda uma importante fonte de renda para produtores e trabalhadores rurais no respectivo município. Objetivamos nessa pesquisa identificar as razões pelas quais a atividade mantém seu padrão tecnológico intacto. Primeiro objetivamos uma descrição do processo produtivo da cera, tanto no passado, quanto no presente, comparando estes momentos e ressaltando o caráter artesanal da atividade, além de analisar a importância atual da atividade para aqueles que ainda lidam com esse tipo de produção, bem como procuramos revelar estrutura histórica e institucional que permeia a lógica e as escolhas destes produtores, a qual pode explicar a preservação destes aspectos artesanais. Utilizando o referencial teórico do institucionalismo, explicamos que a preservação destes aspectos artesanais, ocorre em virtude da prevalência de determinadas instituições, como a memória coletiva cultivada entre os rendeiros idosos e resistentes, a concentração fundiária, responsável pelo arrendamento e também as restritas possibilidades de investimento e poupança no processo produtivo, em face do baixo nível de renda de produtores, os quais com um produto pouco competitivo no mercado, pouco podem fazer para inovar tecnologicamente.

Resistência de genótipos de batata (Solanum spp.) a Diabrotica speciosa (Germar, 1824) (Coleoptera: Chrysomelidae)

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