976 resultados para Guerrero Isaza, Roberto Jose, 1958-


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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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BACKGROUND: We investigated, with magnetic resonance imaging, the distance of the dura mater to the spinal cord in patients without spinal or medullar disease at the 2nd, 5th, and 10th thoracic segments.METHODS: Fifty patients in the supine position underwent magnetic resonance imaging. Medial sagittal slices of the 2nd, 5th, and 10th thoracic segments were measured for the relative distances using the 1.5-T superconducting system (Gyroscan Intera, Philips Medical Systems, Best, the Netherlands). In 10 patients, the angles relative to the tangent at the insertion point on the skin were measured.RESULTS: The posterior dural-spinal cord distance is significantly greater at the midthoracic region (5th thoracic = 5.8 +/- 0.8 mm) than at the upper (2nd thoracic = 3.9 +/- 0.8 mm) and lower thoracic levels (10th thoracic = 4.1 +/- 1.0 mm) (P < 0.015). There were no differences between interspaces T2 and 110. There was no correlation between age and the measured distance between the dura mater and the spinal cord. The entry angle of the needle at T2 was 9.0 degrees +/- 2.5 degrees; at T5, 45.0 degrees +/- 7.4 degrees; and at T10, 9.50 degrees +/- 4.2 degrees.CONCLUSIONS: This study demonstrated that there is greater depth of the posterior subarachnoid space at the T2, T5, and T10 levels. The greater distance was found at T5. (Anesth Analg 2010;110:1494-5)

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The effect of sonication on fluorescence probe solubilization in cationic vesicles of dioctadecyldimethylammonium bromide (DODAB) was investigated by steady-state fluorescence of pyrene (Py), trans-diphenylpolyenes-diphenylbutadiene (DPB), diphenylhexatriene (DPH), and their corresponding 4,4'-dialkyl derivatives 4B4A and 4H4A fluorescence probes. The data indicate that sonication affects the bilayer polarity, the melting temperature (T (m)), and the cooperativity of the melting process due to changes in vesicle morphology. The effect of temperature on the fluorescence intensity and yielding I broken vertical bar(f) and anisotropy < r > shows that the ionizable probes 4B4A and 4H4A are solubilized close to the vesicle interfaces, whereas the non-ionizable DPH and DPB are deeper in the bilayers. Py solubilization indicates that sonicated vesicles exhibit less densely packed bilayers.

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Ameloblastic fibro-odontoma (AFO) is a rare, benign, slow-growing odontogenic tumor, generally asymptomatic and more prevalent in children and adolescents. We report a case of AFO in the mandible of an eight-year-old Caucasian male patient, and review the literature. Intraoral examination revealed a swelling extending from the deciduous second molar to the retromolar triangle, covered with normal mucosa. A panoramic radiograph showed a large, well-demarcated radiolucency with radiopaque areas. The provisional diagnosis was of AFO, and so an incisional biopsy was performed. Histologically, the lesion was composed of connective tissue resembling the dental papilla, with epithelial strands or islands, as well as denticles and amorphous masses of enamel and dentin consistent with a diagnosis of AFO. Surgical excision and curettage of the lesion were performed. The patient has been monitored for eight years and the lesion has not recurred.

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Objective. To examine the histomorphologic and histomorphometric features of tissue from 3 unrelated families with hereditary gingival fibromatosis (HGF).Study design. Twelve affected individuals from 3 HGF families and 3 control subjects were evaluated. Gingival samples were fixed in formalin and embedded in paraffin for hematoxylin and eosin stain to count the number of fibroblast and inflammatory cells. Sirius red staining was performed to quantitate the amount of collagen present.Results. Histomorphologic analysis of HGF showed extension of epithelial rete ridges into the underlying lamina propria and the presence of collagen bundles in the connective tissue. Analysis of the mean area fraction of collagen showed that there were significant increases in the collagen fraction for all HGF types compared with control subjects (P < .05). There were significant increases in the number of fibroblasts for HGFa and HGFb compared with control subjects (P < .05). The number of fibroblasts for HGFc were similar to that for control subjects.Conclusions. The collagen fraction was significantly greater in all HGF types compared with controls. The number of fibroblasts was significantly increased in 2 of the 3 HGF types compared with controls. These data indicate that different mechanisms may be responsible for tissue enlargement in different forms of HGF.

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Since the mid 1980s the Atomic Force Microscope is one the most powerful tools to perform surface investigation, and since 1995 Non-Contact AFM achieved true atomic resolution. The Frequency-Modulated Atomic Force Microscope (FM-AFM) operates in the dynamic mode, which means that the control system of the FM-AFM must force the micro-cantilever to oscillate with constant amplitude and frequency. However, tip-sample interaction forces cause modulations in the microcantilever motion. A Phase-Locked loop (PLL) is used to demodulate the tip-sample interaction forces from the microcantilever motion. The demodulated signal is used as the feedback signal to the control system, and to generate both topographic and dissipation images. As a consequence, a proper design of the PLL is vital to the FM-AFM performance. In this work, using bifurcation analysis, the lock-in range of the PLL is determined as a function of the frequency shift (Q) of the microcantilever and of the other design parameters, providing a technique to properly design the PLL in the FM-AFM system. (C) 2011 Elsevier B.V. All rights reserved.

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

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Spatial analysis and fuzzy classification techniques were used to estimate the spatial distributions of heavy metals in soil. The work was applied to soils in a coastal region that is characterized by intense urban occupation and large numbers of different industries. Concentrations of heavy metals were determined using geostatistical techniques and classes of risk were defined using fuzzy classification. The resulting prediction mappings identify the locations of high concentrations of Pb, Zn, Ni, and Cu in topsoils of the study area. The maps show that areas of high pollution of Ni and Cu are located at the northeast, where there is a predominance of industrial and agricultural activities; Pb and Zn also occur in high concentrations in the northeast, but the maps also show significant concentrations of Pb and Zn in other areas, mainly in the central and southeastern parts, where there are urban leisure activities and trade centers. Maps were also prepared showing levels of pollution risk. These maps show that (1) Cu presents a large pollution risk in the north-northwest, midwest, and southeast sectors, (2) Pb represents a moderate risk in most areas, (3) Zn generally exhibits low risk, and (4) Ni represents either low risk or no risk in the studied area. This study shows that combining geostatistics with fuzzy theory can provide results that offer insight into risk assessment for environmental pollution.