Produção e caracterização de quitooligossacarídeos produzidos pelo fungo Metarhizium anisopliae e avaliação da citotoxicidade em células tumorais

Chitosan is a natural polymer, biodegradable, nontoxic, high molecular weight derived from marine animals, insects and microorganisms. Oligomers of glucosamine (GlcN) and N-acetylglucosamine (GlcNAc) have interesting biological activities, including antitumor effects, antimicrobial activity, antioxidant and others. The alternative proposed by this work was to study the viability of producing chitooligosaccharides using a crude enzymes extract produced by the fungus Metarhizium anisopliae. Hydrolysis of chitosan was carried out at different times, from 10 to 60 minutes to produce chitooligosaccharides with detection and quantification performed by High Performace Liquid Chromatography (HPLC). The evaluation of cytotoxicity of chitosan oligomers was carried out in tumor cells (HepG2 and HeLa) and non-tumor (3T3). The cells were treated for 72 hours with the oligomers and cell viability investigated using the method of MTT. The production of chitosan oligomers was higher for 10 minutes of hydrolysis, with pentamers concentration of 0.15 mg/mL, but the hexamers, the molecules showing greater interest in biological properties, were observed only with 30 minutes of hydrolysis with a concentration of 0.004 mg/mL. A study to evaluate the biological activities of COS including cytotoxicity in tumor and normal cells and various tests in vitro antioxidant activity of pure chitosan oligomers and the mixture of oligomers produced by the crude enzyme was performed. Moreover, the compound with the highest cytotoxicity among the oligomers was pure glucosamine, with IC50 values of 0.30; 0.49; 0.44 mg/mL for HepG2 cells, HeLa and 3T3, respectively. Superoxide anion scavenging was the mainly antioxidant activity showed by the COS and oligomers. This activity was also depending on the oligomer composition in the chitosan hydrolysates. The oligomers produced by hydrolysis for 20 minutes was analyzed for the ability to inhibit tumor cells showing inhibition of proliferation only in HeLa cells, did not show any effect in HepG2 cells and fibroblast cells (3T3)

Avaliação da dolomita funcionalizada para remoção de H2S em gás 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

Avaliação da conformidade de blocos cerâmicos para alvenaria de vedação produzidas na Região Integrada de Desenvolvimento da Grande Teresina

This research presents an outlook of the industries of red ceramic in the region next to the city of Teresina and an analysis of the ceramic products producted in this pole. The microregion investigated possesses 13 boroughs where were identified 32 ceramic in operation, being that 24 are located in Teresina, the ceramic region more important of Piauí, 1 is located in the city of Miguel Leão and 7 is located in Timon city that belongs to the state of Maranhão. The majority of ceramics are pulverized in these two cities, Teresina and Timon , responsible by a largely production independent of distance between fabric and consumer market. Furthermore, there is an artisanal production realized in other boroughs, mainly manual conformation bricks, where are producted diverse types of handicraft and ceramics utilitarian. The objective of this research is to evalue the conformity of ceramic blocks for brick of obstruction made by red ceramic industry of microregion at studying, verifying their pontentialities and adequacy in terms of production. In this research universe made a search of ceramic industries related to the Foundation CEPRO (Foundation Center of Research Social and Economic of Piauí). For the analysis of the ceramic products , were colected 60 crude bricks sample in three industries for their characterization, and 39 burned bricks sample for the Evaluation of Conformity. The results of the characterization made reached a accetptable standard in all formulations and temperature studied. The burned samples were applied to the geometric, physical and mechanical assays according to the ABNT standards (Brazilian Association of Technical Standards). The results of the physical assays showed that all the samples are at the same band recommended by standard. However, through the geometric assays just two industries did not present results according to the standard, due to lack of control in their process such as in their equipments. Taking into account the mechanical properties, only one industry investigated was not according to the standard

Avaliação do desempenho do aço D6 tratado termicamente e netretado em plasma com gaiola catódica visando aplicação industrial

In this research there was an evaluation of the best conditions of nitriding in plasma within a cathodic cage at an atmosphere of 80% N2-20%H2 in samples of tool manganese steel AISI D6, cold working, treated thermally in the following conditions: tension relief, treated thermally to temperature of maximum heat, temperate heat and temperate and temperate heat. A pressure of 2.5mbar and temperatures of 400 and 300ºC com treatment time of two and three hours were used to evaluate its performance as cutting tool (punch) of bicycle backs. Hardness, micro-structural aspects (layer thickness, interface, grain size etc), and crystal phases on the surface were appraised. When treated to tension relief, thermally treated to maximum heat temperature, temperature and temperate heat, the samples presented hardness levels of 243HV, 231HV, 832HV, and 653HV, respectively. The best nitrification conditions were: four hours and 300ºC for heat samples. A superficial hardness of 1000HV and a 108µm thickness for the nitrided layer were found in these samples

Avaliação de heterociclo do tipo mesoiônico solubilizado em sistema microemulsionado para aplicação em dutos

The efficiency of inhibition to corrosion of steel AISI 1018 of surfactant coconut oil saponified (SCO) and heterocyclic type mesoionics (1,3,4-triazólio-2-tiolato) in systems microemulsionados (SCO-ME and SCO-ME-MI) Of type O/A (rich in water emulsion) region with the work of Winsor IV. The systems microemulsionados (SCO-ME and SCO-ME-MI) were evaluated with a corrosion inhibitor for use in saline 10,000 ppm of chloride enriched with carbon dioxide (CO2). The assessment of corrosion inhibitors were evaluated by the techniques of linear polarization resistance (LPR) and loss of weight (MW) in a cell instrumented given the gravity and electrochemical devices. The systems were shooting speed of less than 60 minutes and efficiency of inhibition [SCO-ME (91.25%) and SCO-ME-MI (98.54%)]

Análise e avaliação dos elementos de penetração no solo de equipamentos rodoviários após revestimento

The main objective is to analyze the abrasive wear resistance to the low stress of the elements that make up the organs of road machinery that are exposed directly to contact with abrasives. These samples were analyzed after these elements are coated superficially by the process of welding electrode coated with (SAER) and the manual process of coating type LVOF thermal spraying. As well, is to provide suggestions for a better recovery and return of these elements, which are reducing costs and avoiding downtime in the fronts of service. The samples were made from a substrate of carbon ABNT 1045 tempered steel, following the same specifications and composition of metals and alloys of constituents was followed the standard governing the dimensions of these samples and in accordance with the corresponding size. The results were evaluated by testing the hardness, abrasion resistance to wear by the low stress and the loss of volume involving the microstructure of coatings analyzed

Avaliação do desempenho do aço AISI D2 tratado termicamente e nitretado em plasma com gaiola catódica visando aplicação industrial

In the research, steel samples tool AISI D2, treated thermally, in the conditions: relief of tension, when maximum, seasoned and seasoned was treated thermally in the temperature of revenimento and revenida had been nitrited in plasma with cathodic cage, in atmosphere of 80%N2:20%H2. One used pressure of 2,5 mbar, 400 and 480°C temperatures with treatment time of 3 and 4 hours, with the objective to evaluate its performance in pipes cut tool. It was compared that the performance of the same steel when only thermally treated, both with tension relief. It was evaluated its hardness. Microstructural aspects (the layer thickness, interface, graisn size, etc) and crystalline phases on the surface. Besides, it was verified accomplishment possibility of nitriding simultaneous to annealing treatment. The tempering samples had presented hardness levels of 600 HV, while in nitrited samples these values had been 1100 HV

Avaliação da influência do nacl em pastas de cimento portland para cimentação de poços de petróleo em zonas evaporíticas

One of the major current challenges for oilwell companies is the extraction of oil from evaporitic zones, also known as pre-salt basins. Deep reservoirs are found under thick salt layers formed from the evaporation of sea water. Salt layers seal the flow of oil from underneath rock formations, which store hydrocarbons and increase the probability of success in oil and gas exploration. Oilwells are cemented using Portland-based slurries to promote mechanical stability and zonal isolation. For pre-salt oilwells, NaCl must be added to saturate the cement slurries, however, the presence of salt in the composition of slurries affects their overall behavior. Therefore, the objective of the present study was to evaluate the effect of the addition of 5 to 25% NaCl on selected properties of Portland-based slurries. A series of tests were carried out to assess the rheological behavior, thickening time, free water and ultrassonic compressive strength. In addition, the slurries were also characterized by thermal analysis, X ray diffraction and scanning electron microscopy. The results showed that the addition of NaCl affected the thickening time of the slurries. NaCl contents up to 10% shortened the thickening time of the slurries. On the other hand, concentrations in excess of 20% not only extended the thickening time, but also reduced the strength of hardened slurries. The addition of NaCl resulted in the formation of a different crystalline phase called Friedel´s salt, where free chlorine is bonded to tricalcium aluminate

Avaliação espectrofotométrica do manchamento de resinas odontológicas contendo nanopartículas

Composite resins have been subjected to structural modifications aiming at improved optical and mechanical properties. The present study consisted in an in vitro evaluation of the staining behavior of two nanohybrid resins (NH1 and NH2), a nanoparticulated resin (NP) and a microhybrid resin (MH). Samples of these materials were prepared and immersed in commonly ingested drinks, i.e., coffee, red wine and acai berry for periods of time varying from 1 to 60 days. Cylindrical samples of each resin were shaped using a metallic die and polymerized during 30 s both on the bottom and top of its disk. All samples were polished and immersed in the staining solutions. After 24 hours, three samples of each resin immersed in each solution were removed and placed in a spectrofotome ter for analysis. To that end, the samples were previously diluted in HCl at 50%. Tukey tests were carried out in the statistical analysis of the results. The results revealed that there was a clear difference in the staining behavior of each material. The nanoparticulated resin did not show better color stability compared to the microhybrid resin. Moreover, all resins stained with time. The degree of staining decreased in the sequence nanoparticulated, microhybrid, nanohybrid MH2 and MH1. Wine was the most aggressive drink followed by coffee and acai berry. SEM and image analysis revealed significant porosity on the surface of MH resin and relatively large pores on a NP sample. The NH2 resin was characterized by homogeneous dispersion of particles and limited porosity. Finally, the NH1 resin depicted the lowest porosity level. The results revealed that staining is likely related to the concentration of inorganic pa rticles and surface porosity

Avaliação da potencialidade dos resíduos de gesso de revestimento incorporados em formulações de massas cerâmicas

In building, during the implementation process of major or even minor works, there is a considerable waste of plaster in the steps of coating, making it is a negative factor because of the loss of these processes constructive remains incorporated into buildings, as component, whose final dimensions are higher than those projected. Another negative factor is the disposal of waste gypsum in inappropriate places, thus contributing to the degradation of environmental quality, due to the leaching of this waste and may trigger the formation of sulfuric acid. Therefore, based on this picture, processing and reuse of waste coating, combined with the ceramics industry, which is a strong potential in the reuse of certain types of waste, promote mutual benefits. Thus the overall objective of this work is to conduct a search with scientific and technological aspects, to determine the effect of the incorporation of the residue of plaster for coating, from the building, the formulation of bodies for red ceramic. The residue of plaster coating was collected and characterized. They were also selected raw materials of two ceramic poles of the state of Rio Grande do Norte and formulations have been made with the intention of obtaining those with the best physical and mechanical properties, the residue was added the percentage of 5%, 10%, 15%, 20%, 25% and 30%, in the best formulation of ceramic industry 1 and, according the properties analyses, 5%, 10% and 15% as the best results of ceramic industry 2. The samples were sintered at temperatures of 850 ºC, 950 °C and 1050 °C, the heating rate of 5 ºC / min with isotherm of two hours. They were submitted to testing technology, such as lineal shrinkage, water absorption, apparent porosity, apparent density and bending resistence. The residue incorporation best results in the formulations of mass in red ceramic, were observed between the temperatures of 850 ºC and 950 ºC, in those formulations that have illite clays and medium plastic in their composition, in the range of 0% to 15% residue incorporated

Avaliação de concretos reforçados por confinamento com manta de fibra de vidro estrutural e pré-impreganada

Due to the occurrence of diseases in the use of structural reinforcements in composites, with presentation of concrete blanket detachment, has been identified the need to evaluate the performance of concrete reinforced with glass fiber. This study aims to evaluate these concretes by means of testing methodologies, using concrete with low resistance with structural reinforcement for confinement by preimpregnated glass fiber and traditional fiberglass blanket. The first stage of work was the development of methodologies for analysis, opting for four types, such as the acoustic survey, strength to compressive, the pull-off and ultrasound. Next, tests were carried out using the four selected methodologies in 30 of proof-of-specimens by 5x10 cm, 15 were reinforced with the traditional fiberglass blanket with 5specimens exposed to test a marine environment of marine coastline of Natal-RN and 15 were reinforced with a pre-impregnated glass fiber blanket, as well as 5specimens exposed to a test environment of the marine coastline of Natal-RN. After conducting the acoustic survey, it has been verified a lack of delaminating and air bubbles in the samples, confirming the absence of gross shortcomings in the implementation of the ribs both the traditional fiberglass blanket and in the preimpregnated fiber glass blanket. After carrying out methods of pull-off and compressive strengthening test it was observed that the reinforced proof-bodies with pre-impregnated glass blanket showed maximum stresses higher than the traditional fiberglass blanket; consequently a greater grip with the formation of a smaller area of . fracture, unlike traditional glass mat, which showed lower maximum stresses, with a greater area of fracture. It was also found that the traditional fiberglass blanket presented detachment of blanket-concrete interface, unlike the pre-impregnated fiberglass blanket, which showed a better grip on the blanket-concrete interface. In the trial of ultrasound there was no presence of cracks in the blanket-concrete interface, yielding to both blankets good compactness of the concrete. At the end of this work, they were developed and proposed two methods of testing for evaluation of reinforced concrete structures with composites, for standardization, the acoustic survey and pull-off

Avaliação de inibidores verdes microemulsionados na inibição à corrosão do aço carbono AISI 1020

In general, among the corrosion inhibitors surfactants are the most commonly used compounds, because they are significantly effective by forming protective films on anodic and cathodic areas. In this study, microemulsions containing he biodegradable saponified coconut oil as surfactant (SME-OCS) was used as green corrosion inhibitors. With this purpose, methanolic extracts of Ixora coccinea Linn (IC) and a polar fraction rich in alkaloids (FA) obtained from Croton cajucara Benth solubilized in the SME-OCS system were examined in the presence of AISI 1020 carbon steel, in saline solution (NaCl 3,5 %). The efficiency of corrosion inhibition of IC and FA were evaluated in the following microemulsions: SME-OCS-IC and SME-OCS-FA. The microemulsion system SME-OCS in the presence and absence of IC and FA was assessed by measurements of weight loss and the electrochemical method of polarization resistance, with variation in the concentration of IC and FA (50 - 400 ppm), showing significant results of corrosion inhibition (83,6 % SME-OCS; 92,2 % SME-OCS-FA; and 95,3 % SME-OCS-IC)

Síntese, aplicação e avaliação do efeito do teor de fósforo da celulose fosfatada em argamassa de alvenaria com aditivo comercial a base de hidroxi-etil-metil celulose (HEMC)

Generally, cellulose ethers improves mortar properties such as water retention, workability and setting time, along with adherence to the substrate. However, a major disadvantage of the addition of cellulose ethers in mortars is the delay in hydration of the cement. In this paper a cellulose phosphate (Cp) was synthesized water soluble and has been evaluated the effect of their incorporation into mortar based on Portland cement. Cellulose phosphate obtained was characterized by spectrophotometry Fourier transform infrared (FTIR), X-ray diffraction (XRD), elemental analysis and scanning electron microscopy (SEM). Mortar compositions were formulated with varying phosphorus content in cellulose and cellulose phosphate concentrations, when used in partial or total replacement of the commercial additive based hydroxyethyl methyl cellulose (HEMC). The mortars formulated with additives were prepared and characterized by: testing in the fresh state (consistency index, water retention, bulk density and air content incorporated) and in the hardened state (absorption by capillarity, density, flexural and compression strength). In mixtures the proportion of sand:cement of 1:5 (v / v) and factor a / c = 1.31 and water were held constant. Overall, the results showed that the celluloses phosphates employed in mortars added acted significantly when partially substituting the commercial additive. With regard to consistency index, water retention and bulk density in the fresh state and absorption by capillarity and bulk density apparent in the hardened state, showed no appreciable differences as compared to the commercial additive. The incorporated air content in the fresh state reduced markedly, but did not affect other properties. The mortars with cellulose phosphate, partially replacing the commercial additive showed an improvement of the properties of flexural strength and compressive strength

Avaliação da adição de Nanosílica e silicato de sódio em pastas de cimento para poços de petróleo com baixo gradiente de fratura

The oil wells cementing is a critical step during the phase of well drilling, because problems during the operation of slurry pumping and an incomplete filling of the annular space between the metal casing and the formation can cause the slurry loss. Therefore, the slurry adopted in primary cementing an oil well must be properly dosed so that these problems are avoided during its pumping. When you drill a well in a weak rock formation requires even more careful, because should be a limit of hydrostatic pressure exerted during cementation, that does not occur rock collapse. With the objective of performing the cementing of a well whose formation is weak or unconsolidated are employed lighter slurries. Thus, this study used slurries with sodium silicate and nano silica in concentrations of 0,1; 0,4; 0,7 e 1,0 gpc, in which the slurries with nano silica showed the rheological parameters higher concentrations of up to 0.7 gpc and for concentration of 1.0 the slurry with sodium silicate obtained the highest values, remaining above the limits for application in fields, mainly wells with low fracture gradient, because a significant increase in viscosity may result in an increase in pressure pumping in operations of secondary cementations. Furthermore, there was no decrease in strength with increasing concentration of additive. Then, it is possible use of these additives to formulate Lighter slurry

Nitretação iônica sem efeito de borda :desenvolvimento e avaliação de uma nova técnica

The ionic nitriding process presents some limitations related with the control of the thickness of the layer and its uniformity. Those limitations that happen during the process, are produced due to edge effects, damage caused by arcing arc and hollow cathode, mainly in pieces with complex geometry and under pressures in excess of 1 mbar. A new technique, denominated ASPN (active screen shapes nitriding) it has been used as alternative, for offering many advantages with respect to dc plasma conventional. The developed system presents a configuration in that the samples treated are surrounded by a large metal screen at high voltage cathodic potencials, (varying between 0 and 1200V) and currents up to 1 A. The sample is placed in floting potential or polarized at relatively lower bias voltages by an auxiliary source. As the plasma is not formed directly in the sample surface but in the metal screen, the mentioned effects are eliminated. This mechanism allows investigate ion of the transfer of nitrogen to the substrate. Optical and electronic microscopy are used to exam morphology and structure at the layer. X-ray difration for phase identification and microhardness to evaluate the efficiency of this process with respect to dc conventional nitriding