178 research outputs found

    New Criteria of Indication and Selection of Patients to Cochlear Implant

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    Numerous changes continue to occur in cochlear implant candidacy. In general, these have been accompanied by concomitant and satisfactory changes in surgical techniques. Together, this has advanced the utility and safety of cochlear implantation. Most devices are now approved for use in patients with severe to profound unilateral hearing loss rather then the prior requirement of a bilateral profound loss. Furthermore, studies have begun utilizing short electrode arrays for shallow insertion in patients with considerable low-frequency residual hearing. This technique will allow the recipient to continue to use acoustically amplified hearing for the low frequencies simultaneously with a cochlear implant for the high frequencies. The advances in design of, and indications for, cochlear implants have been matched by improvements in surgical techniques and decrease in complications. The resulting improvements in safety and efficacy have further encouraged the use of these devices. This paper will review the new concepts in the candidacy of cochlear implant. Medline data base was used to search articles dealing with the following topics: cochlear implant in younger children, cochlear implant and hearing preservation, cochlear implant for unilateral deafness and tinnitus, genetic hearing loss and cochlear implant, bilateral cochlear implant, neuropathy and cochlear implant and neural plasticity, and the selection of patients for cochlear implant

    Providing adaptive traffic routing based on user and network context

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    Providing real-time traffic guarantees and fairness based on the availability of network resources has been a major issue presented in the literature. However, due the convergent nature of digital architectures, the increasing demand of upcoming real-time sensitive traffic, such as VoIP, and a higher user´s adaptability (devices, global positioning, content quality, etc.), solutions based on Quality of Service (QoS) turned out to be insufficient in order to meet user´s requirements. Indeed, QoS metrics are network-centered, and mostly related to the dynamic nature of the traffic (such as throughput, delay, jitter, among others). In order to meet the need for a user-centered network, this paper proposes a context-aware solution where the concepts of Quality of Service, Quality of Experience and Adaptive Routing are integrated in order to provide a more dynamic and pro-active approach for the delivery of context-oriented time-sensitive traffic.info:eu-repo/semantics/publishedVersio

    Characterization of Demolished Concretes with Three Different Strengths for Recycling as Coarse Aggregate

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    This paper presents a physical characterization for the recycling into new concretes of three comminuted concretes: C16/20 (“ordinary concrete”), C50/60 (“high strength concrete”), and C70/85 (“very high strength concrete”). The top size of the crushed concretes was 19.1 mm and the size range was 4.75 to 19.1 mm. The characterization was carried out with coarse aggregate liberation, to be prepared and concentrated in a gravity concentration process. The density distribution of the coarse aggregate, cement paste, and sand was carried out in different size ranges (4.75/19.1 mm; 4.75/8.0 mm; 8.0/12.5 mm; and 12.5/19.1 mm) for the three concretes studied. The form factor of the samples, as well as the porosity determination of particles in different density ranges, are presented. The obtained results indicate that the coarse aggregate liberation was more intensive for the low resistance concrete (C16/20), but a reasonable coarse aggregate recovery is possible for all concretes

    Hydrogen peroxide production regulates the mitochondrial function in insulin resistant muscle cells: Effect of catalase overexpression

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    AbstractThe mitochondrial redox state plays a central role in the link between mitochondrial overloading and insulin resistance. However, the mechanism by which the ROS induce insulin resistance in skeletal muscle cells is not completely understood. We examined the association between mitochondrial function and H2O2 production in insulin resistant cells. Our hypothesis is that the low mitochondrial oxygen consumption leads to elevated ROS production by a mechanism associated with reduced PGC1α transcription and low content of phosphorylated CREB. The cells were transfected with either the encoded sequence for catalase overexpression or the specific siRNA for catalase inhibition. After transfection, myotubes were incubated with palmitic acid (500μM) and the insulin response, as well as mitochondrial function and fatty acid metabolism, was determined. The low mitochondrial oxygen consumption led to elevated ROS production by a mechanism associated with β-oxidation of fatty acids. Rotenone was observed to reduce the ratio of ROS production. The elevated H2O2 production markedly decreased the PGC1α transcription, an effect that was accompanied by a reduced phosphorylation of Akt and CREB. The catalase transfection prevented the reduction in the phosphorylated level of Akt and upregulated the levels of phosphorylated CREB. The mitochondrial function was elevated and H2O2 production reduced, thus increasing the insulin sensitivity. The catalase overexpression improved mitochondrial respiration protecting the cells from fatty acid-induced, insulin resistance. This effect indicates that control of hydrogen peroxide production regulates the mitochondrial respiration preventing the insulin resistance in skeletal muscle cells by a mechanism associated with CREB phosphorylation and β-oxidation of fatty acids

    Dentin deproteinization effect on bond strength of self-adhesive resin cements

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    This study examined the effect of deproteinization on the bond strength between self-adhesive resin cements and dentin surfaces that were untreated (control), acid-etched, or acid-etched and subjected to a post-etch deproteinization treatment. Cylinders of RelyX Unicem or BisCem (n = 6) cement were build-up on the dentin surfaces and tested to determine shear strength. The results were analyzed using two-way ANOVA and Tukey's test (5%). While neither dentin pretreatment improved the bond strength for RelyX Unicem, deproteinization treatments resulted in greater bond strength in BisCem specimens while acid etching alone did not improve the performance of the material

    Inquérito sorológico para a detecção de anticorpos contra o vírus da Imunodeficiência Humana (VIH) em crianças internadas em enfermaria geral

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    São apresentados os resultados de um inquérito sorológico para a detecção de anticorpos contra o Vírus da Imunodeficiência Humana (VIH), em grupo não selecionado de crianças, internadas numa enfermaria geral de pediatria. Foram testados 441 pacientes pelo método ELISA, com uma positividade de 1,1 %, cujos resultados foram confirmados pelos testes de Western-Blot e/ou ImunoBlot. Nenhum dos cinco pacientes com teste positivo apresentou história de transfusão anterior, enquanto que 4,3% dos pacientes estudados apresentaram história transfusional. Todas as mães apresentaram também testes ELISA positivos. Em quatro casos, pelo menos um dos genitores referiu uso de drogas por via endovenosa. Em todas as crianças, o modo de transmissão foi vertical. A partir desses achados sugere-se a necessidade de a equipe de saúde tomar precauções quando da manipulação de sangue ou secreções. Recomenda-se a realização de inquéritos anônimos em enfermarias de hospitais gerais para auxiliar na determinação da real prevalência das infecções pelo VIH
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