Complexos metálicos de cobalto, níquel e cobre com a Pirazina-2-carboxamida e 4- hidrazida ácida piridincarboxílica: síntese e caracterização

This work involved the synthesis, characterization and proposing the molecular structure of coordination compounds involving ligands pyrazine-2-carboxamide (PZA) and 4- hydrazide acidic pyridine carboxylic (INH) and metals of the first transition series (M = Co2+, Ni2+ and Cu2+). For the characterization of the compounds used were analytical techniques such as infrared absorption spectroscopy average (FT-IR) molar conductivity measurements, CHN elemental analysis, EDTA Complexometric, measurement of melting point, X-ray diffraction by powder method, Thermogravimetry (TG) and Differential Thermal Analysis (DTA) and Simultaneous Differential Scanning Calorimetry (DSC). The absorption spectra in the infrared region suggested that the ligand coordination to the metal center occurs through the carbonyl oxygen atom and nitrogen alpha pyrazine ring to those complexes formed with PZA. For INH complexes with metal-ligand coordination is through the carbonyl oxygen and nitrogen of the terminal hydrazide grouping. The conductivity measurements of the complexes in aqueous solution they suggest to all behavior of the type 1:2 electrolytes, and conduct of non-electrolytes in acetonitrile. The results obtained by CHN elemental analysis and EDTA Complexometric allowed to infer the stoichiometry of the compounds synthesized. For all of the complexes obtained was possible to record the melting points, neither of which melted near the melting temperature of the free ligands. The X-ray diffraction showed that the complexes of pyrazinamide exhibited diffraction lines, suggesting that these compounds are crystalline, while compounds of isoniazid, with the exception of cobalt, exhibited diffraction lines, indicating that they are crystalline. The results from the TG-DTA and DSC allowed information regarding the dehydration and thermal decomposition of these complexes

Tratamento de borra de petróleo com sistemas microemulsionados

During the storage of oil, sludge is formed in the bottoms of tanks, due to decantation, since the sludge is composed of a large quantity of oil (heavy petroleum fractions), water and solids. The oil sludge is a complex viscous mixture which is considered as a hazardous waste. It is then necessary to develop methods and technologies that optimize the cleaning process, oil extraction and applications in industry. Therefore, this study aimed to determine the composition of the oil sludge, to obtain and characterize microemulsion systems (MES), and to study their applications in the treatment of sludge. In this context, the Soxhlet extraction of crude oil sludge and aged sludge was carried out, and allowing to quantify the oil (43.9 % and 84.7 % - 13 ºAPI), water (38.7 % and 9.15 %) and solid (17.3 % and 6.15 %) contents, respectively. The residues were characterized using the techniques of X-ray fluorescence (XRF), Xray diffraction (XRD) and transmission Infrared (FT-IR). The XRF technique determined the presence of iron and sulfur in higher proportions, confirming by XRD the presence of the following minerals: Pyrite (FeS2), Pyrrhotite (FeS) and Magnetite (Fe3O4). The FT-IR showed the presence of heavy oil fractions. In parallel, twelve MES were prepared, combining the following constituents: two nonionic surfactants (Unitol L90 and Renex 110 - S), three cosurfactants (butanol, sec-butanol and isoamyl alcohol - C), three aqueous phase (tap water - ADT, acidic solution 6 % HCl, and saline solution - 3.5 % NaCl - AP) and an oil phase (kerosene - OP). From the obtained systems, a common point was chosen belonging to the microemulsion region (25 % [C+S] 5 % OP and AP 70 %), which was characterized at room temperature (25°C) by viscosity (Haake Rheometer Mars), particle diameter (Zeta Plus) and thermal stability. Mixtures with this composition were applied to oil sludge solubilization under agitation at a ratio of 1:4, by varying time and temperature. The efficiencies of solubilization were obtained excluding the solids, which ranged between 73.5 % and 95 %. Thus, two particular systems were selected for use in storage tanks, with efficiencies of oil sludge solubilization over 90 %, which proved the effectiveness of the MES. The factorial design delimited within the domain showed how the MES constituents affect the solubilization of aged oil sludge, as predictive models. The MES A was chosen as the best system, which solubilized a high amount of aged crude oil sludge (~ 151.7 g / L per MES)

Eficiência de extração de cobre e níquel utilizando sistemas microemulsionados bifásicos e trifásicos

The environmental impact due to the improper disposal of metal-bearing industrial effluents imposes the need of wastewater treatment, since heavy metals are nonbiodegradable and hazardous substances that may cause undesirable effects to humans and the environment. The use of microemulsion systems for the extraction of metal ions from wastewaters is effective when it occurs in a Winsor II (WII) domain, where a microemulsion phase is in equilibrium with an aqueous phase in excess. However, the microemulsion phase formed in this system has a higher amount of active matter when compared to a WIII system (microemulsion in equilibrium with aqueous and oil phases both in excess). This was the reason to develop a comparative study to evaluate the efficiency of two-phases and three-phases microemulsion systems (WII and WIII) in the extraction of Cu+2 and Ni+2 from aqueous solutions. The systems were composed by: saponified coconut oil (SCO) as surfactant, n-Butanol as cosurfactant, kerosene as oil phase, and synthetic solutions of CuSO4.5H2O and NiSO4.6H2O, with 2 wt.% NaCl, as aqueous phase. Pseudoternary phase diagrams were obtained and the systems were characterized by using surface tension measurements, particle size determination and scanning electron microscopy (SEM). The concentrations of metal ions before and after extraction were determined by atomic absorption spectrometry. The extraction study of Cu+2 and Ni+2 in the WIII domain contributed to a better understanding of microemulsion extraction, elucidating the various behaviors presented in the literature for these systems. Furthermore, since WIII systems presented high extraction efficiencies, similar to the ones presented by Winsor II systems, they represented an economic and technological advantage in heavy metal extraction due to a small amount of surfactant and cosurfactant used in the process and also due to the formation of a reduced volume of aqueous phase, with high concentration of metal. Considering the reextraction process, it was observed that WIII system is more effective because it is performed in the oil phase, unlike reextraction in WII, which is performed in the aqueous phase. The presence of the metalsurfactant complex in the oil phase makes possible to regenerate only the surfactant present in the organic phase, and not all the surfactant in the process, as in WII system. This fact allows the reuse of the microemulsion phase in a new extraction process, reducing the costs with surfactant regeneration

Paralelização em GPU da segmentação vascular com extração de Centerlines por Height Ridges

The vascular segmentation is important in diagnosing vascular diseases like stroke and is hampered by noise in the image and very thin vessels that can pass unnoticed. One way to accomplish the segmentation is extracting the centerline of the vessel with height ridges, which uses the intensity as features for segmentation. This process can take from seconds to minutes, depending on the current technology employed. In order to accelerate the segmentation method proposed by Aylward [Aylward & Bullitt 2002] we have adapted it to run in parallel using CUDA architecture. The performance of the segmentation method running on GPU is compared to both the same method running on CPU and the original Aylward s method running also in CPU. The improvemente of the new method over the original one is twofold: the starting point for the segmentation process is not a single point in the blood vessel but a volume, thereby making it easier for the user to segment a region of interest, and; the overall gain method was 873 times faster running on GPU and 150 times more fast running on the CPU than the original CPU in Aylward

Desenvolvimento de bionanocompósitos: nano e microcristais de celulose com poli (álcool vinílico) e poli (ácido lático)

This work has the main objective to obtain nano and microcrystals of cellulose, extracted from the pineapple leaf fibres (PALF), as reinforcement for the manufacture of biocomposite films with polymeric matrices of Poly(vinyl alcohol) (PVA) and Poly(lactic acid) (PLA). The polymer matrices and the nano and microcrystals of cellulose were characterised by means of TGA, FTIR and DSC. The analysis was performed on the pineapple leaves to identify the macro and micronutrients. The fibers of the leaves of the pineapple were extracted in a desfibradeira mechanical. The PALF extracted were washed to remove washable impurities and subsequently treated with sodium hydroxide (NaOH) and sodium hypochlorite (NaClO) in the removal of impurities, such as fat, grease, pectates, pectin and lignin. The processed PALF fibers were hydrolysed in sulfuric acid (H2SO4) at a concentration of 13.5 %, to obtain nano and microcrystals of cellulose. In the manufacture of biocomposite films, concentrations of cellulose, 0 %, 1 %, 3 %, 6 %, 9% and 12% were used as reinforcement to the matrices of PVA and PLA. The PVA was dissolved in distilled water at 80 ± 5 oC and the PLA was dissolved in dichloromethane at room temperature. The manufacture of biocompósitos in the form of films was carried out by "casting". Tests were carried out to study the water absorption by the films and mechanical test of resistance to traction according to ASTM D638-10 with a velocity of 50 mm/min.. Chi-square statistical test was used to check for the existence of significant differences in the level of 0.05: the lengths of the PALF, lengths of the nano and microcrystals of cellulose and the procedures used for the filtration using filter syringe of 0.2 μm or filtration and centrifugation. The hydrophilicity of biocompósitos was analysed by measuring the contact angle and the thickness of biocompósitos were compared as well as the results of tests of traction. Statistical T test - Student was also applied with the significance level (0.05). In biodegradation, Sturm test of standard D5209 was used. Nano and microcrystals of cellulose with lengths ranging from 7.33 nm to 186.17 nm were found. The PVA films showed average thicknesses of 0.153 μm and PLA 0.210 μm. There is a strong linear correlation directly proportional between the traction of the films of PVA and the concentration of cellulose in the films (composite) (0,7336), while the thickness of the film was correlated in 0.1404. Nano and microcrystals of cellulose and thickness together, correlated to 0.8740. While the correlation between the cellulose content and tensile strength was weak and inversely proportional (- 0,0057) and thickness in -0.2602, totaling -0,2659 in PLA films. This can be attributed to the nano and microcrystals of cellulose not fully adsorbed to the PLA matrix. In the comparison of the results of the traction of the two polymer matrices, the nano and microcrystals have helped in reducing the traction of the films (composite) of PLA. There was still the degradation of the film of PVA, within a period of 20 days, which was not seen in the PLA film, on the other hand, the observations made in the literature, the average time to start the degradation is above 60 days. What can be said that the films are biodegradable composites, with hydrophilicity and the nano and microcrystals of cellulose, contribute positively in the improvement of the results of polymer matrices used.

Otimização da extração de polissacarídeos sulfatados da alga vermelha Gracilaria birdiae e análise da atividade anticoagulante e antioxidante

The sulfated polysaccharides (SP) from the edible red seaweed Gracilaria birdiae were obtained using five different condition extraction (GB1: Water; GB1p: Water/proteolysis; GB1s: Water/sonication; GB1sp: Water/sonication/proteolysis; GB2s: NaOH/sonication; GB2sp: NaOH/sonication/proteolysis. The yield (g) increased in the following order GB2sp>GB1sp>GB1p>GB2s>GB1s>GB1. However, the amount of SP extracted increased in different way GB2sp>GB1p>GB1>GB1sp>GB1s>GB2s. Infrared and electrophoresis analysis showed that all conditions extracted the same SP. In addition, monosaccharide composition showed that ultrasound promotes the extraction of other polysaccharides than SP. In the prothrombin time (PT) test, which evaluates the extrinsic coagulation pathway, none of the samples showed anticoagulant activity. While in the activated partial thromboplastin time (aPTT) test, which evaluates the intrinsic coagulation pathway, all samples showed anticoagulant activity, except GB2s. The aPTT activity decreased in the order of GB1sp>GB2sp>GB1p>GB1>GB1s>GB2s. Total capacity antioxidant (TCA) of the SP was also affected by condition extraction, since GB2s and GB1 showed lower activity in comparison to the other conditions. In conclusion, the conditions of SP extraction influence their biological activities and chemical composition. The data showed NaOH/sonication/proteolysis was the best condition to extract anticoagulant and antioxidant SPs from Gracilaria birdiae.

Determinação de CD, PB, e TL em água produzida por HR-CS GF AAS após extração em ponto nuvem

Produced water is a major problem associated with the crude oil extraction activity. The monitoring of the levels of metals in the waste is constant and requires the use of sensitive analytical techniques. However, the determination of trace elements can often require a pre-concentration step. The objective of this study was to develop a simple and rapid analytical method for the extraction and pre-concentration based on extraction phenomenon cloud point for the determination of Cd, Pb and Tl in produced water samples by spectrometry of high resolution Absorption source continues and atomization graphite furnace. The Box Behnken design was used to obtain the optimal condition of extraction of analytes. The factors were evaluated: concentration of complexing agent (o,o-dietilditilfosfato ammonium, DDTP), the concentration of hydrochloric acid and concentration of surfactant (Triton X -114). The optimal condition obtained through extraction was: 0,6% m v-1 DDTP, HCl 0,3 mol L-1 and 0,2% m v-1 of Triton X - 114 for Pb; 0,7% m v-1 DDTP, HCl 0,8 mol L-1 and 0,2% m v-1 Triton X-114 for Cd. For Tl was evidenced that best extraction condition occurs with no DDTP, the extraction conditions were HCl 1,0 mol L-1 e 1,0% m v-1 de Triton X - 114. The limits of detection for the proposed method were 0,005 µg L-1 , 0,03 µg L-1 and 0,09 µg L-1 to Cd, Pb and Tl, Respectively. Enrichment factors Were greater than 10 times. The method was applied to the water produced in the Potiguar basin, and addition and recovery tests were performed, and values were between 81% and 120%. The precision was expressed with relative standard deviation (RSD) is less than 5%

Extração do corante do fruto de castanhola (Terminalia catappa Linn) e estudos dos seus compostos fenólicos, antocianinas e atividade antioxidante

The Terminalia catappa Linn belonging to Combretaceae family, popularly known as castanets, has fruits consists of a fleshy pulp, rounded seed and a very hard shell. The natural pigmentation existing in the fruit of castanet indicates the presence of anthocyanins, phenolic nature components belonging to the group of flavonoids, which have antioxidant activity. This research was conducted with the castanets and aimed to the study of factors influencing the extraction of dyes from its pulp. The extracts were obtained using a reactor enjaquetado by solid-liquid extraction. The factors were evaluated as temperature, time, solvent ratio and pH extraction. Adopting a factorial design of 24 , with 4 repetitions at the central point, the effects of these factors on the extraction process were analyzed using Statistica 7.0 software. The antioxidant activity (AA), the content of phenolic compounds (CFT) and the total monomeric anthocyanin content (AMT) were evaluated as response variables planning. Statistical analysis of the results, the effects that influenced the extraction were different for each response (CFT, AMT and AA). However, the pH was significant for the extraction of all compounds. The kinetic behavior of the dye extraction was also studied for phenolic compounds, monomeric anthocyanins and antioxidant activity, in which the equilibrium was reached after 90 minutes of extraction. To study the stability of anthocyanins temperature was the factor that most influenced the stability, however the concentration and pH also played a part.

Desenvolvimento de metodologia de extração e pré-concentração utilizando sistema microemulsionado para determinação de Cd, Co, Cu, Ni, Pb e Tl em águas naturais e produzidas por HR-CS AAS

The determination and monitoring of metallic contaminants in water is a task that must be continuous, leading to the importance of the development, modification and optimization of analytical methodologies capab le of determining the various metal contaminants in natural environments, because, in many cases, the ava ilable instrumentation does not provide enough sensibility for the determination of trace values . In this study, a method of extraction and pre- concentration using a microemulsion system with in the Winsor II equilibrium was tested and optimized for the determination of Co, Cd, P b, Tl, Cu and Ni through the technique of high- resolution atomic absorption spectrometry using a continuum source (HR-CS AAS). The optimization of the temperature program for the graphite furnace (HR-CS AAS GF) was performed through the pyrolysis and atomization curves for the analytes Cd, Pb, Co and Tl with and without the use of different chemical modifiers. Cu and Ni we re analyzed by flame atomization (HR-CS F AAS) after pre-concentr ation, having the sample introduction system optimized for the realization of discrete sampling. Salinity and pH levels were also analyzed as influencing factors in the efficiency of the extraction. As final numbers, 6 g L -1 of Na (as NaCl) and 1% of HNO 3 (v/v) were defined. For the determination of the optimum extraction point, a centroid-simplex statistical plan was a pplied, having chosen as the optimum points of extraction for all of the analytes, the follo wing proportions: 70% aqueous phase, 10% oil phase and 20% co-surfactant/surfactant (C/S = 4). After extraction, the metals were determined and the merit figures obtained for the proposed method were: LOD 0,09, 0,01, 0,06, 0,05, 0,6 and 1,5 μg L -1 for Pb, Cd, Tl, Co, Cu and Ni, re spectively. Line ar ranges of ,1- 2,0 μg L -1 for Pb, 0,01-2,0 μg L -1 for Cd, 1,0 - 20 μg L -1 for Tl, 0,1-5,0 μg L -1 for Co, 2-200 μg L -1 and for Cu e Ni 5-200 μg L -1 were obtained. The enrichment factors obtained ranged between 6 and 19. Recovery testing with the certified sample show ed recovery values (n = 3, certified values) after extraction of 105 and 101, 100 and 104% for Pb, Cd, Cu and Ni respectively. Samples of sweet waters of lake Jiqui, saline water from Potengi river and water produced from the oil industry (PETROBRAS) were spiked and the recovery (n = 3) for the analytes were between 80 and 112% confirming th at the proposed method can be used in the extraction. The proposed method enabled the sepa ration of metals from complex matrices, and with good pre-concentration factor, consistent with the MPV (allowed limits) compared to CONAMA Resolution No. 357/2005 which regulat es the quality of fresh surface water, brackish and saline water in Brazil.

Remoção de corantes utilizando tensoativos: extração por ponto de nuvem e floculação iônica

The textile sector is one of the main contributors to the generation of industrial wastewaters due to the use of large volumes of water, which has a high organic load content. In these, it is observed to the presence of dyes, surfactants, starch, alcohols, acetic acid and other constituents, from the various processing steps of the textiles. Hence, the treatment of textile wastewater becomes fundamental before releasing it into water bodies, where they can cause disastrous physical-chemical changes for the environment. Surfactants are substances widely used in separation processes and their use for treating textile wastewaters was evaluated in this research by applying the cloud point extraction and the ionic flocculation. In the cloud point extraction was used as surfactant nonylphenol with 9.5 ethoxylation degree to remove reactive dye. The process evaluation was performed in terms of temperature, surfactant and dye concentrations. The dye removal reached 91%. The ionic flocculation occurs due to the presence of calcium, which reacts with anionic surfactant to form insoluble surfactants capable of attracting the organic matter by adsorption. In this work the ionic flocculation using base soap was applied to the treatment of synthetic wastewater containing dyes belonging to three classes: direct, reactive, and disperse. It was evaluated by the influence of the following parameters: surfactant and electrolyte concentrations, stirring speed, equilibrium time, temperature, and pH. The flocculation of the surfactant was carried out in two ways: forming the floc in the effluent itself and forming the floc before mixing it to the effluent. Removal of reactive and direct dye, when the floc is formed into textile effluent was 97% and 87%, respectively. In the case where the floc is formed prior to adding it to the effluent, the removal to direct and disperse dye reached 92% and 87%, respectively. These results show the efficience of the evaluated processes for dye removal from textile wastewaters.

Avaliação da biodegradação do dibenzotiofeno utilizando lodos ativados

During the oil refining process a huge discard volume of water occurs, which carries the contaminants from the process. A class of contaminant compounds resulting from the petrochemical industry are the Polyaromatic Hydrocarbons (PAH's). To evaluate the biodegradation of Dibenzothiophene in refinery water a synthetic wastewater was prepared to be treated using activated sludge. For this, a 2 3 Composite Design (plus 3 central points and six axial points) was carried out. The planning had as independent variables (factors) the initial concentration of DBT, pH and time of biodegradation. Biodegradation of DBT was assayed following the parameters COD, pH, temperature, SS, VSS, FVS, SVI. Concerned to the chromatographic conditions, a methodology was validated in order to verify the presence of DBT and its metabolite, 2-HBF, in the final wastewater treated by activated sludge system using a liquid - liquid extraction coupled to HPLC / UV analysis. The parameters used for validation were DL, QL, linearity, recovery and repeatability. As for optimization, the results indicated that the studied methodology can be used in monitoring the DBT degradation and 2- HBF by activated sludge, as they showed excellent linearity values, coefficients of variation, so as satisfactory recovery percentage. COD reduction efficiency tests showed an average percentage of 64.4%. The increasing trend for the results for the TSS and VSS tests showed that the activated sludge was well tailored. The best operating conditions for the reduction of COD were observed when operated with median concentrations of DBT, a higher time to biodegradation, and pH in both the acidic range as the basic one. The biodegradability of the DBT was confirmed by determining the presence of HBF-2. The highest concentrations of HBF-2 were obtained in extreme concentrations of DBT and pH, and higher biodegradation times.

Extração, caracterização e avaliação bioativa do extrato de Arrabidaea chica

The use of plants for medicinal purposes is ancient, with widespread application in medicinal drugs. Although plants are promising sources for the discovery of new molecules of pharmacological interest, estimates show that only 17% of them have been studied for their possible use in medicine. Thus, biodiversity of Brazilian flora represents an immense potential for economic use by the pharmaceutical industry. The plant Arrabidaea chica, popularly known as “pariri”, is common in the Amazon region, and it is assigned several medicinal properties. The leaves of this plant are rich in anthocyanins, which are phenolic compounds with high antioxidant power. Antioxidant compounds play a vital role in the prevention of neurological and cardiovascular diseases, cancer and diabetes, among others. Within the anthocyanins found in Arrabidaea chica, stands out Carajurin (6,7-dihydroxy-5,4’- dimethoxy-flavilium), which is the major pigment encountered in this plant. The present work aimed to study on supercritical extraction and conventional extraction (solid-liquid extraction) in leaves of Arrabidaea chica, evaluating the efficiency of the extractive processes, antioxidant activity and quantification of Carajurin contained in the extracts. Supercritical extraction used CO2 as solvent with addition of co-solvent (ethanol/water mixture) and were conducted by the dynamic method in a fixed bed extractor. The trials followed a 24-1 fractional factorial design, the dependent variables were: process yield, concentration of Carajurin and antioxidant activity; and independent variables were: pressure, temperature, concentration of co-solvent (v/v) and concentration of water in the co-solvent mixture (v/v). Yields (mass of dry extract/mass of raw material used) obtained from supercritical extraction ranged from 15.1% to 32%, and the best result was obtained at 250 bar and 40 °C, co-solvent concentration equal to 30% and concentration of water in the co-solvent mixture equal to 50%. Through statistical analysis, it was found that the concentration of co-solvent revealed significant effect on the yield. Yields obtained from conventional extractions were of 8.1% (water) and 5.5% (ethanol). Through HPLC (High-performance liquid chromatography) analysis, Carajurin was quantified in all the extracts and concentration values (Carajurin mass/mass of dry extract) ranged between 1% and 2.21% for supercritical extraction. For conventional extraction, Carajurin was not detected in the aqueous extract, while the ethanol extract showed Carajurin content of 7.04%, and therefore, more selective in Carajurin than the supercritical extraction. Evaluation of antioxidant power (radical 2,2-diphenyl-1-picrylhydrazyl – DPPH – sequestration method) of the supercritical extracts resulted in EC50 values (effective concentration which neutralizes 50% of free radicals) ranged from 38.34 to 86.13 μg/mL, while conventional extraction resulted in EC50 values of 167.34 (water) and 42.58 (ethanol) μg/mL. As for the quantification of total phenolic content (Folin-Ciocalteau analysis) of the supercritical extracts resulted in values ranged from 48.93 and 88.62 mg GAE/g extract (GAE = Gallic Acid Equivalents), while solid-liquid extraction resulted in values of 37.63 (water) and 80.54 (ethanol) mg GAE/g extract. The good antioxidant activity cannot be attributed solely to the presence of Carajurin, but also the existence of other compounds and antioxidants in Arrabidaea chica. By optimizing the experimental design, it was possible to identify the experiment that presented the best result considering the four dependent variables together. This experiment was performed under the following conditions: pressure of 200 bar, temperature of 40 °C, co-solvent concentration equal to 30% and concentration of water in the co-solvent mixture equal to 30%. It is concluded that, within the studied range, it is possible to purchase the optimum result using milder operating conditions, which implies lower costs and greater ease of operation.

Aplicação de nanoemulsão ácida em acidificação de poços de petróleo

A constante busca da indústria de petróleo pelo aumento de produção à um baixo custo operacional faz necessário o desenvolvimento de tecnologias que una as duas necessidades. A Acidificação de matriz é um método de estimulação frequentemente empregado para aumentar produção de um poço de petróleo com um custo menor se comparado a um fraturamento. O objetivo deste trabalho é estudar a obtenção de nanoemulsões ácidas para aplicação em acidificação de matriz. As nanoemulsões são capazes de retardar reações, por diminuir a difusão do ácido no meio, possibilitando a acidificação em reservatórios com baixa permeabilidade. Os reagentes utilizados para formar os sistemas nanoemulsionados foram UNT L90/OMS e RNX 110 como tensoativos, Sec-butanol como cotensoativo, Xileno e Querosene como fase óleo e Solução de HCl como fase aquosa. As nanoemulsões foram obtidas a partir da diluição de microemulsões com água ou solução de HCl. Foi realizado estudo das tensões superficiais, estudo das cinéticas de reação, avaliação da injeção em rocha carbonática e remoção de borra asfáltica. As nanoemulsões apresentaram tensão superficial menor que suas microemulsões de origem. As nanoemulsões tiveram êxito em retardar a reação entre CaCO3 e HCl, onde o sistema mais eficiente é composto por UNT L90/OMS, Secbutanol, Querosene e solução de HCl. As nanoemulsões foram eficientes em formar wormholes em plugs de carbonato calcitico com baixa permeabilidade natural. As wormholes proporcionaram incremento de permeabilidade alcançando valores de até 390 mD. O sistema ácido apresentou bom resultado de remoção de borra asfáltica, mostrando o potencial das nanoemulsões em remover esse tipo de dano. Conclui-se que os sistemas nanoemulsionados têm grande potencial de aplicação em acidificação de matriz.

Extração, caracterização e prospecção de atividades farmacológicas de polissacarídeos sulfatados da macroalga verde Caulerpa prolifera

This study aimed to extract, characterize and conduct a prospective analysis of pharmacological activities of sulfated polysaccharides from green seaweed Caulerpa prolifera. Seven fractions (CP-0.3/CP-0.5/CP-0.7/CP-0.9/CP-1.1/CP-1.5/CP-2.0) were obtained from C. prolifera by alkaline proteolysis followed by sequential precipitation in acetone. The physicochemical analyzes indicated that C. prolifera synthesizes a homogalactan (CP-0.9) and different populations of sulfated heteropolysaccharides. In the analysis of anticoagulant activity, all fractions except CP-0.3, influenced the intrinsic coagulation pathway. All fractions showed antioxidant activity in six different assays being more pronounced in hydrogen peroxide scavenging assay, especially CP-0.3, CP-0.7 and CP-0.9 (which obtained 61% of hydrogen peroxide scavenging), in ferric chelation assay (especially CP-0.9 with 56% chelation) and cupric chelation assay (especially CP-2.0 with 78% chelation). With respect to immunomodulatory activity, the presence of CP-0.3, CP-0.7 and CP-0.9 showed an immunogenic potential, increasing the production of nitric oxide (NO) by 48, 142 and 163 times, respectively. Conversely, the NO synthesis fell 73% after the activation of macrophages by LPS, incubated concurrently with CP-2.0. The anti-adipogenic activity of the fractions was also evaluated and CP-1.5 was able to reduce the differentiation of pre-adipocytes (3T3-L1) into adipocytes by 60%, without affecting the cell viability. The fractions CP-0.3, CP-0.5 and CP-0.9 reduced the viability of the HeLa cells (human cervical adenocarcinoma) by 55% and CP-1.5 reduced the viability of the 786-0 cells (human renal adenocarcinoma) by 75%. Leishmanicidal activity and microbicide effect against Carbapenem-resistant Klebsiella pneumoniae (KPC) have not been identified. However, the viability of Staphylococcus epidermidis was reduced by 23.8% in the presence of CP -1.5. All fractions were able to change the formation of calcium oxalate crystals. CP-0.3, CP-0.5 and CP-1.1 only promoted the formation of COD type crystals with a very small size (1 μm). Confocal microscopy and zeta potential data of crystals formed in the presence of the samples showed that the polysaccharides present in the fractions must interact with calcium ions present throughout the crystal lattice, affecting the growth and morphology of crystals The results described herein indicate that the fractions rich in polysaccharides obtained from the green seaweed C. prolifera present a multi therapeutic potential, and subsequent purification steps, as well as research on the mechanisms of action by which these polymers act should be investigated.

Uso de correntropia na generalização de funções cicloestacionárias e aplicações para a extração de características de sinais modulados

Information extraction is a frequent and relevant problem in digital signal processing. In the past few years, different methods have been utilized for the parameterization of signals and the achievement of efficient descriptors. When the signals possess statistical cyclostationary properties, the Cyclic Autocorrelation Function (CAF) and the Spectral Cyclic Density (SCD) can be used to extract second-order cyclostationary information. However, second-order cyclostationary information is poor in nongaussian signals, as the cyclostationary analysis in this case should comprise higher-order statistical information. This paper proposes a new mathematical tool for the higher-order cyclostationary analysis based on the correntropy function. Specifically, the cyclostationary analysis is revisited focusing on the information theory, while the Cyclic Correntropy Function (CCF) and Cyclic Correntropy Spectral Density (CCSD) are also defined. Besides, it is analytically proven that the CCF contains information regarding second- and higher-order cyclostationary moments, being a generalization of the CAF. The performance of the aforementioned new functions in the extraction of higher-order cyclostationary characteristics is analyzed in a wireless communication system where nongaussian noise exists.