157 resultados para RBF


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

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

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In this paper we presente a classification system that uses a combination of texture features from stromal regions: Haralick features and Local Binary Patterns (LBP) in wavelet domain. The system has five steps for classification of the tissues. First, the stromal regions were detected and extracted using segmentation techniques based on thresholding and RGB colour space. Second, the Wavelet decomposition was applied in the extracted regions to obtain the Wavelet coefficients. Third, the Haralick and LBP features were extracted from the coefficients. Fourth, relevant features were selected using the ANOVA statistical method. The classication (fifth step) was performed with Radial Basis Function (RBF) networks. The system was tested in 105 prostate images, which were divided into three groups of 35 images: normal, hyperplastic and cancerous. The system performance was evaluated using the area under the ROC curve and resulted in 0.98 for normal versus cancer, 0.95 for hyperplasia versus cancer and 0.96 for normal versus hyperplasia. Our results suggest that texture features can be used as discriminators for stromal tissues prostate images. Furthermore, the system was effective to classify prostate images, specially the hyperplastic class which is the most difficult type in diagnosis and prognosis.

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Pós-graduação em Engenharia Elétrica - FEIS

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

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Non-Hodgkin lymphomas are of many distinct types, and different classification systems make it difficult to diagnose them correctly. Many of these systems classify lymphomas only based on what they look like under a microscope. In 2008 the World Health Organisation (WHO) introduced the most recent system, which also considers the chromosome features of the lymphoma cells and the presence of certain proteins on their surface. The WHO system is the one that we apply in this work. Herewith we present an automatic method to classify histological images of three types of non-Hodgkin lymphoma. Our method is based on the Stationary Wavelet Transform (SWT), and it consists of three steps: 1) extracting sub-bands from the histological image through SWT, 2) applying Analysis of Variance (ANOVA) to clean noise and select the most relevant information, 3) classifying it by the Support Vector Machine (SVM) algorithm. The kernel types Linear, RBF and Polynomial were evaluated with our method applied to 210 images of lymphoma from the National Institute on Aging. We concluded that the following combination led to the most relevant results: detail sub-band, ANOVA and SVM with Linear and RBF kernels.

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Ceramic parts are increasingly replacing metal parts due to their excellent physical, chemical and mechanical properties, however they also make them difficult to manufacture by traditional machining methods. The developments carried out in this work are used to estimate tool wear during the grinding of advanced ceramics. The learning process was fed with data collected from a surface grinding machine with tangential diamond wheel and alumina ceramic test specimens, in three cutting configurations: with depths of cut of 120 mu m, 70 mu m and 20 mu m. The grinding wheel speed was 35m/s and the table speed 2.3m/s. Four neural models were evaluated, namely: Multilayer Perceptron, Radial Basis Function, Generalized Regression Neural Networks and the Adaptive Neuro-Fuzzy Inference System. The models'performance evaluation routines were executed automatically, testing all the possible combinations of inputs, number of neurons, number of layers, and spreading. The computational results reveal that the neural models were highly successful in estimating tool wear, since the errors were lower than 4%.

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

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Background/Aims: The effects of cigarette smoke (CS) on cyclosporine (CsA)-induced nephrotoxicity are poorly studied. This study aims to assess the effects of previous exposure to CS on CsA nephrotoxicity. Methods: Rats were either exposed to CS or sham (S) procedures for 10 min twice a day for 20 weeks. From the 16th to the 20th week, they received a low-salt diet. Beginning with the 17th week, they were given 2.5 mg/day CsA or vehicle (VH) for 3 weeks. The final groups were VH/CS, CsA/CS, VH/S, and CsA/S. On day 141, glomerular filtration rate (GFR), renal blood flow (RBF), renal vascular resistance (RVR), tubulointerstitial fibrosis, and CsA blood levels were measured and immunohistochemistry was analyzed for renal alpha-smooth muscle actin (SMA), nitrotyrosine, and vimentin. Results: CsA decrease in GFR was enhanced by CS exposure. CsA associated with CS induced higher periglomerular alpha-SMA and renal nitrotyrosine expression. CsA decreased RBF, but increased RVR, tubulointerstitial fibrosis, and alpha-SMA and renal vimentin expression. These changes and the CsA blood levels were not affected by CS exposure. Conclusion: CS aggravated the CsA-induced impairment of GFR and CS associated with CsA caused the development of periglomerular structural lesions and oxidative stress in a rat model of CsA nephrotoxicity. Copyright (C) 2012 S. Karger AG, Basel

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Cyclosporine (CsA) remains an important immunosuppressant for transplantation and for treatment of autoimmune diseases. The most troublesome side effect of CsA is renal injury. Acute CsA-induced nephrotoxicity is characterized by reduced renal blood flow (RBF) and glomerular filtration rate (GFR) due to afferent arteriole vasoconstriction. Annexin A1 (ANXA1) is a potent anti-inflammatory protein with protective effect in renal ischemia/reperfusion injury. Here we study the effects of ANXA1 treatment in an experimental model of acute CsA nephrotoxicity. Salt-depleted rats were randomized to treatment with VH (vehicles 1 mL/kg body weight/day), ANXA1 (Ac2-26 peptide 1 mg/kg body weight/day intraperitoneally), CsA (20 mg/kg body weight/day subcutaneously) and CsA + ANXA1 (combination) for seven days. We compared renal function and hemodynamics, renal histopathology, renal tissue macrophage infiltration and renal ANXA1 expression between the four groups. CsA significantly impaired GFR and RBF, caused tubular dilation and macrophage infiltration and increased ANXA1 renal tissue expression. Treatment with ANXA1 attenuated CSA-induced hemodynamic changes, tubular injury and macrophage infiltration. ANXA1 treatment attenuated renal hemodynamic injury and inflammation in an acute CsA nephrotoxicity model.

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OBJECTIVE To assess the effects of atorvastatin (ATORV) on renal function after bilateral ureteral obstruction (BUO), measuring inulin clearance and its effect on renal hemodynamic, filtration, and inflammatory response, as well as the expression of Aquaporin-2 (AQP2) in response to BUO and after the release of BUO. METHODS Adult Munich-Wistar male rats were subjected to BUO for 24 hours and monitored during the following 48 hours. Rats were divided into 5 groups: sham operated (n = 6); sham + ATORV (n = 6); BUO (n = 6); BUO + ATORV (10 mg/kg in drinking water started 2 days before BUO [n = 5]; and BUO + ATORV (10 mg/kg in drinking water started on the day of the release of BUO [n = 5]). We measured blood pressure (BP, mm Hg); inulin clearance (glomerular filtration rate [GFR]; mL/min/100 g); and renal blood flow (RBF, mL/min, by transient-time flowmeter). Inflammatory response was evaluated by histologic analysis of the interstitial area. AQP2 expression was evaluated by electrophoresis and immunoblotting. RESULTS Renal function was preserved by ATORV treatment, even if initiated on the day of obstruction release, as expressed by GFR, measured by inulin clearance. Relative interstitial area was decreased in both BUO + ATORV groups. Urine osmolality was improved in the ATORV-treated groups. AQP2 protein expression decreased in BUO animals and was reverted by ATORV treatment. CONCLUSION ATORV administration significantly prevented and restored impairment in GFR and renal vascular resistance. Furthermore, ATORV also improved urinary concentration by reversing the BUO-induced downregulation of AQP2. These findings have significant clinical implication in treating obstructive nephropathy. UROLOGY 80: 485.e15-485.e20, 2012. (c) 2012 Elsevier Inc.

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Abstract Introduction We conducted the present study to examine the effects of hypertonic saline solution (7.5%) on cardiovascular function and splanchnic perfusion in experimental sepsis. Methods Anesthetized and mechanically ventilated mongrel dogs received an intravenous infusion of live Escherichia coli over 30 minutes. After 30 minutes, they were randomized to receive lactated Ringer's solution 32 ml/kg (LR; n = 7) over 30 minutes or 7.5% hypertonic saline solution 4 ml/kg (HS; n = 8) over 5 minutes. They were observed without additional interventions for 120 minutes. Cardiac output (CO), mean arterial pressure (MAP), portal and renal blood flow (PBF and RBF, respectively), gastric partial pressure of CO2 (pCO2; gas tonometry), blood gases and lactate levels were assessed. Results E. coli infusion promoted significant reductions in CO, MAP, PBF and RBF (approximately 45%, 12%, 45% and 25%, respectively) accompanied by an increase in lactate levels and systemic and mesenteric oxygen extraction (sO2ER and mO2ER). Widening of venous-arterial (approximately 15 mmHg), portal-arterial (approximately 18 mmHg) and gastric mucosal-arterial (approximately 55 mmHg) pCO2 gradients were also observed. LR and HS infusion transiently improved systemic and regional blood flow. However, HS infusion was associated with a significant and sustained reduction of systemic (18 ± 2.6 versus 38 ± 5.9%) and mesenteric oxygen extraction (18.5 ± 1.9 versus 36.5 ± 5.4%), without worsening other perfusional markers. Conclusion A large volume of LR or a small volume of HS promoted similar transient hemodynamic benefits in this sepsis model. However, a single bolus of HS did promote sustained reduction of systemic and mesenteric oxygen extraction, suggesting that hypertonic saline solution could be used as a salutary intervention during fluid resuscitation in septic patients.