206 resultados para Functional product


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This work deals with the existence of mild solutions for a class of impulsive functional differential equations of the neutral type associated with the family of linear closed (not necessarily bounded) operators {A(t) : t is an element of 1}. (C) 2009 Elsevier Ltd. All rights reserved.

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We establish the existence of mild solutions for a class of impulsive second-order partial neutral functional differential equations with infinite delay in a Banach space. (C) 2009 Published by Elsevier Ltd

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In this work we study the existence and uniqueness of pseudo-almost periodic solutions for a first-order abstract functional differential equation with a linear part dominated by a Hille-Yosida type operator with a non-dense domain. (C) 2009 Published by Elsevier Ltd

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In this paper we study the existence of mild solutions for a class of first order abstract partial neutral differential equations with state-dependent delay. (C) 2008 Elsevier Ltd. All rights reserved.

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In this paper we study the approximate controllability of control systems with states and controls in Hilbert spaces, and described by a second-order semilinear abstract functional differential equation with infinite delay. Initially we establish a characterization for the approximate controllability of a second-order abstract linear system and, in the last section, we compare the approximate controllability of a semilinear abstract functional system with the approximate controllability of the associated linear system. (C) 2008 Elsevier Ltd. All rights reserved.

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We establish existence of mild solutions for a class of abstract second-order partial neutral functional differential equations with unbounded delay in a Banach space.

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The paper considers the existence and uniqueness of almost automorphic mild solutions to some classes of first-order partial neutral functional-differential equations. Sufficient conditions for the existence and uniqueness of almost automorphic mild solutions to the above-mentioned equations are obtained. As an application, a first-order boundary value problem arising in control systems is considered. (C) 2007 Elsevier Ltd. All fights reserved.

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By using the theory of semigroups of growth a, we discuss the existence of mild solutions for a class of abstract neutral functional differential equations. A concrete application to partial neutral functional differential equations is considered. (C) 2011 Elsevier Ltd. All rights reserved.

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Some patients are no longer able to communicate effectively or even interact with the outside world in ways that most of us take for granted. In the most severe cases, tetraplegic or post-stroke patients are literally `locked in` their bodies, unable to exert any motor control after, for example, a spinal cord injury or a brainstem stroke, requiring alternative methods of communication and control. But we suggest that, in the near future, their brains may offer them a way out. Non-invasive electroencephalogram (EEG)-based brain-computer interfaces (BCD can be characterized by the technique used to measure brain activity and by the way that different brain signals are translated into commands that control an effector (e.g., controlling a computer cursor for word processing and accessing the internet). This review focuses on the basic concepts of EEG-based BC!, the main advances in communication, motor control restoration and the down-regulation of cortical activity, and the mirror neuron system (MNS) in the context of BCI. The latter appears to be relevant for clinical applications in the coming years, particularly for severely limited patients. Hypothetically, MNS could provide a robust way to map neural activity to behavior, representing the high-level information about goals and intentions of these patients. Non-invasive EEG-based BCIs allow brain-derived communication in patients with amyotrophic lateral sclerosis and motor control restoration in patients after spinal cord injury and stroke. Epilepsy and attention deficit and hyperactive disorder patients were able to down-regulate their cortical activity. Given the rapid progression of EEG-based BCI research over the last few years and the swift ascent of computer processing speeds and signal analysis techniques, we suggest that emerging ideas (e.g., MNS in the context of BC!) related to clinical neuro-rehabilitation of severely limited patients will generate viable clinical applications in the near future.

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Motor cortex stimulation oriented by functional cortical mapping is used mainly for treating otherwise intractable neurological disorders, however. its mechanism of action remains elusive. Herein, we present a new method for functional mapping of the rat motor cortex using non-invasive transdural electrical stimulation. This method allows a non-invasive mapping of the surface of the neocortex providing a differentiation of representative motor areas. This Study may facilitate further investigation about the mechanisms mediating the effects of electrical stimulation, possibly benefiting patients who do not respond to this neuromodulation therapy. (c) 2009 Elsevier B.V. All rights reserved.

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Dysphagia is a symptom associated with an array of anatomical and functional changes which must be assessed by a multidisciplinary team to guarantee optimal evaluation and treatment, preventing potential complications. Aim: The aim of the present study is to present the combined protocol of clinical and swallowing videoendoscopy carried by ENT doctors and speech therapists in the Dysphagia Group of the ENT Department - University Hospital. Materials and Methods: Retrospective study concerning the use of a protocol made up of patient interview and clinical examination, followed by an objective evaluation with swallowing videoendoscopy. The exam was performed in 1,332 patients from May 2001 to December 2008. There were 726 (54.50%) males and 606 (45.50%) females, between 22 days and 99 years old. Results: We found: 427 (32.08%) cases of normal swallowing, 273 (20.48%) mild dysphagia, 224 (16.81%) moderate dysphagia, 373 (27.99%) severe dysphagia and 35 (2.64%) inconclusive exams. Conclusion: The combined protocol (Otolaryngology and Speech Therapy), is a good way to approach the dysphagic patient, helping to achieve early and safe deglutition diagnosis as far as disorder severity and treatment are concerned.

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Background: Recent studies have assessed the direct effects of smoking on cardiac remodeling and function. However, the mechanisms of these alterations remain unknown. The aim of this study was to investigate de role of cardiac NADPH oxidase and antioxidant enzyme system on ventricular remodeling induced by tobacco smoke. Methods: Male Wistar rats that weighed 200-230 g were divided into a control group (C) and an experimental group that was exposed to tobacco smoke for a period of two months (ETS). After the two-month exposure period, morphological, biochemical and functional analyses were performed. Results: The myocyte cross-sectional area and left ventricle end-diastolic dimension was increased 16.2% and 33.7%, respectively, in the ETS group. The interstitial collagen volume fraction was also higher in ETS group compared to the controls. In addition to these morphological changes, the ejection fraction and fractional shortening were decreased in the ETS group. Importantly, these alterations were related to augmented heart oxidative stress, which was characterized by an increase in NADPH oxidase activity, increased levels of lipid hydroperoxide and depletion of antioxidant enzymes (e.g., catalase, superoxide dismutase and glutathione peroxidase). In addition, cardiac levels of IFN-gamma, TNF-alpha and IL-10 were not different between the groups. Conclusion: Cardiac alterations that are induced by smoking are associated with increased NADPH oxidase activity, suggesting that this pathway plays a role in the ventricular remodeling induced by exposure to tobacco smoke. Copyright (C) 2011 S. Karger AG, Basel

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The monobloc frontofacial osteotomy provides aesthetic and functional improvement in the treatment of various craniofacial deformities. This procedure, through highly complex, has had some significant associated complication, such as cerebrospinal fluid leakage, hematoma, infection, and bone resorption. Distraction has been successfully used to gradually elongate bone and soft tissue. This method seems to provide improved results over conventional surgery, with less morbidity. We present a case of a patient with Apert syndrome who underwent monobloc advancement using the Rigid External Device (RED) device and who developed a transient bilateral amaurosis on the fourth postoperative day before distraction. A second procedure was performed to push back the frontal bandeau, maintaining the device in position. The blindness was resolved with this procedure as well as treatment with systemic steroids. The distraction was started thereafter, and the desired improvement was acquired. To our knowledge, this is the first case of transient bilateral amaurosis in a patient undergoing monobloc distraction.

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The no. 0-14 cleft involves the midline of the face and cranium. It may include both a true and a false median cleft lip, with or without associated hypotelorism or hypertelorism. The no. 0 cleft is the most common of the craniofacial clefts. The objective of this study was to review the functional outcome and aesthetic results of the different techniques applied for each case. We have conducted a retrospective analysis of our series consisting of 32 cases of Tessier no. 0 cleft, in the period between 1997 and 2007. The patients were divided into 2 groups: those with the true median cleft and those with the false median cleft. The clinical findings, lip malformation, alveolar cleft, nasal appearance, septal involvement, associated deformities, and surgical procedures, were all reviewed. Holoprosencephaly was present in 9 cases, with a false median cleft upper lip and an absence of the premaxilla, septum, and columella (only 1 patient underwent lip and columella reconstruction at 2 years of age). Nine patients had an incomplete median cleft lip. Seven of these cases had associated median alveolar cleft, and 1 had an intranasal tumor, associated with lipoma of corpus callosum, characteristic of the Pai syndrome. Six cases of a bifid nose were seen, 2 of which were associated with an alveolar median cleft and hypertelorism. An isolated median alveolar cleft was present in 7 cases, 2 of them associated with a no. 30 cleft. This article presents a large series of Tessier no. 0 cleft, describing the differences between the false and the true median cleft. The surgical procedures may vary in relation to the type of involvement.

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Objective: To investigate the possible role of chromatin texture parameters, nuclear morphology, DNA ploidy and clinical functional status in discriminating benign from malignant adrenocortical tumors (ACT). Patients and Methods: Forty-eight cases of clinically benign (n=40) and clinically malignant (n=8) ACT with a minimum of 5-years` follow-up were evaluated for chromatin texture parameters (run length, standard deviation, configurable run length, valley, slope, peak and other 21 Markovian features that describe the distribution of the chromatin in the nucleus), nuclear morphology (nuclear area, nuclear perimeter, nuclear maximum and minumum diameter, nuclear shape), and DNA ploidy. Nuclear parameters were evaluated in Feulgen-stained 5 mu m paraffin-sections analyzed using a CAS 200 image analyzer. Results: Since ACTs present different biological features in children and adults, patients were divided into two groups: children (<= 15 years) and adults (>15 years). In the group of children DNA ploidy presented a marginal significance (p=0.05) in discriminating ACTs. None of the parameters discriminated between malignant and benign ACT in the adult group. Conclusion: ACTs are uncommon and definitive predictive criteria for malignancy remain uncertain, particularly in children. Our data point to DNA content evaluated by image analysis as a new candidate tool for this challenging task. Texture image analysis did not help to differentiate malignant from benign adrenal cortical tumors in children and adults.