984 resultados para intercalated clays
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Periodontal disease progress by destructive acute phases intercalated by reparative chronic phases. The aim of this study was to investigate the clinical and histological evidence of the periodontal disease reparative phase by analyzing bone wall conditions inside periodontal pockets and histologic images of periodontal pockets, identified in relevant publications. 81 patients with periodontitis, were randomly assigned into this study. Clinical and radiographic parameters were established to diagnose periodontal disease providing a sample of 133 diseased areas, which were treated by modified Widman flap. Documentation by digital photography were recorded in the surgery. Relevant publications showing histological images of periodontal pockets, were identified in Medline, PubMed and Google data base, were scanned and digitalized. All images obtained were evaluated and the presences of the reparative evidence in the zone around the underlying destroyed alveolar bone were critically analyzed. All periodontal bone defects, showed cortical bone reparations at different levels inside periodontal bone defects. All histologic images of periodontal pockets identified in relevant publications showed repaired gingival-attached connective tissue localized above underlying destroyed alveolar bone. All the evidences analyzed in this study suggested that periodontal disease is predominantly chronic, quiescent, showing reparative phases in different levels.
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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The geophysical methods may be employed in aquifer system studies, as determination of groundwater level, soil/rock contact, beyond estimative of the aquifer thickness horizon. The geoeletric methods are particularly relevant in evaluations of the oilfields systems, due to directs relations between porosity and electrical resistivity, which allow inferences about oil and gas production. The indirect estimative of the productions in free aquifers system is something complex before of the diverse variables responsible for factors or physical phenomena, as clays minerals, which conditioned the physical parameters by electric geophysical methods. This paper present analyzed correlation among electrical resistivity, chargeability and direct measure flow in shallow wells, for determination of statistical relationships between parameters and evaluation of the geological constraints evolved. The study count with the 23 shallow wells located in free aquifer, constituted by alteration materials of the granites localized in Caçapava do Sul (RS). The geophysical data are acquired by vertical electric sounding in Schlumberger array. The correlations between electrical resistivity and flow, chargeability and flow, thickness of the soil/saprolite and flow indicated relationships between physical and hydrogeologic parameters, with variations conditioned by factors as porosity, permeability, besides intrinsic geological heterogeneities such soil variable thickness and rock fragments with several alteration degrees.
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The ferruginous sandstone (Serra da Galga member) from Marilia formation present in sedimentary mining triangle plateaus - MG (southeast Brazil) is still not properly characterized, as well as the presence of a rich layer Fe nodules which is not properly understood, as are the alteration products of this material that may be linked to the presence of refractory clays which are characterized by intimate relationship between Fe and Al. Aluminum is widely present on top of these plateaus. This course conclusion paper characterized the mineralogy and distribution of smaller elements both rust sandstone evolved as soil above this sandstone. The characterization has been done by using X-ray fluorescence techniques (XRF), the iron was removed by using the CBD method (dithionito-citratebicarbonate), and X-ray diffraction (XRD) and analysis of the products extracted by the CBD method by ICP- OES were made to characterize the material. The results of the XRF show great variation of Al and Si, Fe with almost constant behavior in the average depth of 110 cm, where it has the highest concentration levels. Fe appear associated with the V and Ce. CDB results show a clear relation of Fe with Al. Al does not have in this case compared with Cr or any other item. The concentration of extracted Al was always below the concentration of Fe. In the region, the formation of this Latosols- Gleysols system is subject to topography and its influence on local water regime, a regime that has direct influence on the formation of supergene accumulations as in the area and results in aluminum accumulation in refractory clays exploited by IBAR mining
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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The southwestern region of the São Luís-Grajaú Basin has a rare outcrop of the Codó Formation (upper Aptian) with seven outstanding microbialite bioherms along the left margin of the Tocantins river, near Imperatriz (MA). Resting on sandstones of the Grajaú Formation, the Codó Formation presents: 1) a 20 cm thick basal calcilutite with gypsite pseudomorphs and some fossil tree stems; 2) metric dark shales with carbonate nodules and thin intercalated carbonate layers, enclosing some microbial laminites; 3) a 2 cm thick upper breccia composed of microbialite fragments and other carbonate clasts, with halite hoppers on the top; 4) the carbonate bioherms, which partially overlie the extensive shales and interrupt them laterally, as well as the breccia. The bioherms in the northern part of the outcrop are thicker (<2 m) and have interbedded dark shales, whereas the southern are thinner and continuous in the vertical direction. In general, they are composed of irregular gently to strongly wavy microbial laminites, sometimes with pseudocolumnar to conical lamination. All microbialites with highest synoptic relief (<20 cm) look like columnar stromatolites on weathered lateral expositions. In plan view, the horizontal sections of these microbialites are circular to slightly elliptic, sometimes forming very small channels (N60W) filled with fine breccia. The highest bed of the northern bioherm has mixed microbial laminites and columnar stromatolites, where intercolumnar spaces were filled with microbialite clasts, fish bones, plant fragments and very small probable crustacean coprolites. Several fractures and deformation in this upper bed indicate an initial brecciation process probably caused by subaerial exposure. In microscopic scale, the lamination is smooth, diffuse, defined by subtle granulation differences of very fine granular calcite crystals within micrite, but oxide levels, dissolution surfaces or thin precipitated calcite veneers...
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Located in northeastern Brazil, the evolution of Araripe Basin has been associated with the fragmentation of Gondwana and opening of the South Atlantic. The Santana Formation belongs to the post-rift sequence of the basin and is characterized by the presence of laminated limestones in the lower portion (Mb. Crato), evaporite (Ipubi) and siliciclastics (Mb. Romualdo). For better understanding of the Romualdo's stratigraphy, depositional environments and tract of systems, a stratigraphic analysis was made with representative columnar sections of the unit. Sedimentary facies have been described in detail, as well as paleocurrents measured at different stratigraphic levels. It was found that the contact of Mb. Romualdo with the carbonate-evaporite section (Mbs. Crato and Ipubi) is a unconformity, evidenced by residual lags and thin layers of conglomerates above the contact. Above the conglomeratic levels predominate fine sandstones / medium interlayered with calciferous green shales. The percentage of shales increases towards the top, featuring retrogradational stacking culminating in layers of coquinas, excellent stratigraphic mark in the basin. Thin layers of coquins of gastropods comprising equinoids, located on the shale section, present in three sections marine deposits are associated with surfaces ravine. The upper section is characterized by recurrent facies of green shales, sandstones intercalated with sandstones progressively become more frequent towards the top of the unit, featuring the regressive part of the cycle. The sandstones present cross-stratification, often with mud clasts and clay layers in the foresets, and beddings of flaser type and wavy in heterolitic facies, suggesting the action of tidal currents. Paleocurrents measured in the sandstones show gaps with opposite flow directions outlining bipolar standards, which reinforce the interpretation of shallow marine environment influenced by tides during the sedimentation...
TDEM survey in urban environmental for hydrogeological study at USP campus in Sao Paulo city, Brazil
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In this work, some TDEM (Time Domain Electromagnetic) results at USP (University of Sao Paulo) campus in Sao Paulo city, Brazil, are presented. The data were acquired focusing on two mains objectives: (i) to map geoelectrical stratigraphy of Sao Paulo sedimentary basin, emphasizing on hydrogeological studies about sedimentary and crystalline aquifers, and (ii) to analyze the viability of TDEM data acquisition use in urban environment. The study area is located in Sao Paulo basin border, characterized by Resende and Sao Paulo formations, which are constituted by sand-clays sediments over a granite-gneissic basement. Two equipments were used in order to acquire database: Protem47 (low power), and Protem57-MK2 (high power). Capacitive noise affect obtained data with Protem47 due to the presence of metal pipes buried at IAG/USP (Institute of Astronomy, Geophysics, and Atmospheric Science) test site at USP. On the other hand, capacitive noise did not affect acquired data with Protem57-MK2, and the data present high signal to noise ratio. Surveys helped in determining sedimentary and crystalline aquifers, characterized by a fracture zone with water inside basin basement (conductive zone). Results show good agreement with local geology obtained from lithological boreholes located in the study areas. Moreover, it shows that TDEM method can be used in urban environments with a countless potential in hydrogeological studies, offering great reliability. Studies showed that main TDEM-method limitation at USP was the lack of space for opening the transmitter loop. Results are very promising and open new perspectives for TDEM-method use in urban environments as this area remains unexplored. (C) 2011 Elsevier B.V. All rights reserved.
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Objective To evaluate and compare the intraobserver and interobserver reliability and agreement for the biparietal diameter (BPD), abdominal circumference (AC), femur length (FL) and estimated fetal weight (EFW) obtained by two-dimensional ultrasound (2D-US) and three-dimensional ultrasound (3D-US). Methods Singleton pregnant women between 24 and 40 weeks were invited to participate in this study. They were examined using 2D-US in a blinded manner, twice by one observer, intercalated by a scan by a second observer, to determine BPD, AC and FL. In each of the three examinations, three 3D-US datasets (head, abdomen and thigh) were acquired for measurements of the same parameters. We determined EFW using Hadlock's formula. Systematic errors between 3D-US and 2D-US were examined using the paired t-test. Reliability and agreement were assessed by intraclass correlation coefficients (ICCs), limits of agreement (LoA), SD of differences and proportion of differences below arbitrary points. Results We evaluated 102 singleton pregnancies. No significant systematic error between 2D-US and 3D-US was observed. The ICC values were higher for 3D-US in both intra- and interobserver evaluations; however, only for FL was there no overlap in the 95% CI. The LoA values were wider for 2D-US, suggesting that random errors were smaller when using 3D-US. Additionally, we observed that the SD values determined from 3D-US differences were smaller than those obtained for 2D-US. Higher proportions of differences were below the arbitrarily defined cut-off points when using 3D-US. Conclusion 3D-US improved the reliability and agreement of fetal measurements and EFW compared with 2D-US.
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Objective To evaluate the intra- and interobserver reliability of assessment of three-dimensional power Doppler (3D-PD) indices from single spherical samples of the placenta. Methods Women with singleton pregnancies at 2440 weeks' gestation were included. Three scans were independently performed by two observers; Observer 1 performed the first and third scan, intercalated by the scan of Observer 2. The observers independently analyzed the 3D-PD datasets that they had previously acquired using four different methods, each using a spherical sample: random sample extending from basal to chorionic plate; random sample with 2 cm3 of volume; directed sample to the region subjectively determined as containing more color Doppler signals extending from basal to chorionic plate; or directed sample with 2 cm3 of volume. The vascularization index (VI), flow index (FI) and vascularization flow index (VFI) were evaluated in each case. The observers were blinded to their own and each other's results. Additional evaluation was performed according to placental location: anterior, posterior and fundal or lateral. Intra- and interobserver reliability was assessed by intraclass correlation coefficients (ICC). Results Ninety-five pregnancies were included in the analysis. All three placental 3D-PD indices showed only weak to moderate reliability (ICC < 0.66 and ICC < 0.48, intra- and interobserver, respectively). The highest values of ICC were observed when using directed spherical samples from basal to chorionic plate. When analyzed by placental location, we found lower ICCs for lateral and fundal placentae compared to anterior and posterior ones. Conclusion Intra- and interobserver reliability of assessment of placental 3D-PD indices from single spherical samples in pregnant women greater than 24 weeks' gestation is poor to moderate, and clinical usefulness of these indices is likely to be limited. Copyright (c) 2012 ISUOG. Published by John Wiley & Sons, Ltd.
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Nano-biocomposites based on a biodegradable bacterial copolyester, poly(hydroxybutyrate-co-hydroxyvalerate), have been elaborated with an organo-modified montmorillonite (OMMT) clay as nanofiller, and acetyl tributyl citrate as plasticizer. The corresponding (nano)structures, thermal and mechanical properties, permeability, and biodegradability have been determined. Polyhydroxyalkanoates are very thermal sensitive then to follow the degradation the corresponding matrices have been analyzed by size exclusion chromatography. The results indicate that the addition of the plasticizer decreases the thermo-mechanical degradation, during the extrusion. These nano-biocomposites show an intercalated/exfoliated structure with good mechanical and barrier properties, and an appropriated biodegradation kinetic. Intending to understand the changes in the thermal properties, the nano-biocomposites were characterized by thermal gravimetric analysis and differential scanning calorimetry. The presence of the OMMT clay did not influence significantly the transition temperatures. However, the filler not only acted as a nucleating agent which enhanced the crystallization, but also as a thermal barrier, improving the thermal stability of the biopolymer. The results indicated that the addition of the plasticizer reduces the glass transition temperature and the crystalline melting temperature. The plasticizer acts as a processing aid and increases the processing temperature range (lower melting temperature).
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Objective: Cardiopulmonary bypass is associated with ischemia-reperfusion injury to multiple organs. We aimed to evaluate whether remote ischemic preconditioning performed the day before surgery for congenital heart disease with cardiopulmonary bypass attenuates the postoperative inflammatory response and myocardial dysfunction. Methods: This was a prospective, randomized, single-blind, controlled trial. Children allocated to remote ischemic preconditioning underwent 4 periods of 5 minutes of lower limb ischemia by a blood pressure cuff intercalated with 5 minutes of reperfusion. Blood samples were collected 4, 12, 24, and 48 hours after cardiopulmonary bypass to evaluate nuclear factor kappa B activation in leukocytes by quantification of mRNA of I kappa B alpha by real-time quantitative polymerase chain reaction and for interleukin-8 and 10 plasma concentration measurements by enzyme-linked immunosorbent assay. Myocardial dysfunction was assessed by N-terminal pro-B-type natriuretic peptide and cardiac troponin I plasma concentrations, measured by chemiluminescence, and clinical parameters of low cardiac output syndrome. Results: Twelve children were allocated to remote ischemic preconditioning, and 10 children were allocated to the control group. Demographic data and Risk Adjustment for Congenital Heart Surgery 1 classification were comparable in both groups. Remote ischemic preconditioning group had lower postoperative values of N-terminal pro-B-type natriuretic peptide, but cardiac troponin I levels were not significantly different between groups. Interleukin-8 and 10 concentrations and I kappa B alpha gene expression were similar in both groups. Postoperative morbidity was similar in both groups; there were no postoperative deaths in either group. Conclusions: Late remote ischemic preconditioning did not provide clinically relevant cardioprotection to children undergoing cardiopulmonary bypass. (J Thorac Cardiovasc Surg 2012;144:178-83)