BAHA (Bone Anchored Hearing Aid) indicações, resultados funcionais e comparação com cirurgia reconstrutiva de orelha

INTRODUÇÃO: O BAHA (Bone Ancored Hearing Aid) é um dispositivo auditivo de condução óssea que propaga o som diretamente à orelha interna, utilizado principalmente em pacientes com perda auditiva condutiva associada a atresia aural, mas atualmente também em perdas mistas e neurossensoriais. OBJETIVO: Revisar as principais indicações do BAHA, analisar os resultados audiométricos e os benefícios proporcionados aos pacientes, e compará-los com outras modalidades de tratamento além de comparar os dados da literatura com nossa casuística de 13 pacientes. MÉTODO: A pesquisa foi realizada em bases de dados abrangendo trabalhos em inglês, espanhol e português, sem limites de intervalos de anos, comparando com os resultados dos nossos 13 pacientes submetidos a esse procedimento, no período de 2000 a 2009. RESULTADOS: A maioria dos trabalhos mostrou vantagens do BAHA em comparação à cirurgia reconstrutiva, tanto pelos resultados audiológicos quanto em relação a complicações e recidiva. Os resultados pós-operatórios nos 13 pacientes operados por nossa equipe foi satisfatório e compatível com os da literatura, com fechamento do gap aéreo-ósseo em 7 pacientes e gap aéreo-ósseo de até 10 dB em 6 pacientes. Não houve complicações pós-operatórias. CONCLUSÃO: O BAHA é uma ótima opção de tratamento para pacientes com surdez condutiva bilateral, fato demonstrado pelos bons resultados audiológicos e por se tratar de um procedimento cirúrgico relativamente simples e com baixa taxa de complicações. Os estudos mais recentes vêm abordando seu uso para surdez condutiva e neurossensorial unilateral.

Hearing loss and acquired immune deficiency syndrome: systematic review

PURPOSE: To investigate the occurrence of hearing loss in individuals with HIV/AIDS and their characterization regarding type and degree. RESEARCH STRATEGY: It was conducted a systematic review of the literature found on the electronic databases PubMed, EMBASE, ADOLEC, IBECS, Web of Science, Scopus, Lilacs and SciELO. SELECTION CRITERIA: The search strategy was directed by a specific question: "Is hearing loss part of the framework of HIV/AIDS manifestations?", and the selection criteria of the studies involved coherence with the proposed theme, evidence levels 1, 2 or 3, and language (Portuguese, English and Spanish). DATA ANALYSIS: We found 698 studies. After an analysis of the title and abstract, 91 were selected for full reading. Out of these, 38 met the proposed criteria and were included on the review. RESULTS: The studies reported presence of conductive, sensorineural, and mixed hearing loss, of variable degrees and audiometric configurations, in addition to tinnitus and vestibular disorders. The etiology can be attributed to opportunistic infections, ototoxic drugs or to the action of virus itself. The auditory evoked potentials have been used as markers of neurological alterations, even in patients with normal hearing. CONCLUSION: HIV/AIDS patients may present hearing loss. Thus, programs for prevention and treatment of AIDS must involve actions aimed at auditory health.

Glycerol oxidation on nickel based nanocatalysts in alkaline medium – Identification of the reaction products

In this work, carbon supported nickel based nanoparticles were prepared by impregnation method and used as anode electrocatalysts for the glycerol conversion. These metallic powders were mixed with a suitable amount of a Nafion/water solution to make catalytic inks which were then deposited onto the surface of carbon Toray used as a conductive substrate. Long-term electrolyses of glycerol were carried out in alkaline medium by chronoamperometry experiments. Analysis of the oxidation products was performed with ion-exclusion liquid chromatography which separates the analytes by ascending pKa. The spectroscopic measurements have shown that the cobalt content in the anode composition did contribute to the CAC bond cleavage of the initial molecule of glycerol.

Mass extinctions, galactic orbits in the solar neighborhood and the Sun: a connection?

The orbits of the stars in the disk of the Galaxy, and their passages through the Galactic spiral arms, are a rarely mentioned factor of biosphere stability which might be important for long-term planetary climate evolution, with a possible bearing on mass extinctions. The Sun lies very near the co-rotation radius, where stars revolve around the Galaxy in the same period as the density wave perturbations of the spiral arms. conventional wisdom generally considers that this status makes for few passages through the spiral arms. Controversy still surrounds whether time spent inside or around spiral arms is dangerous to biospheres and conductive to mass extinctions. Possible threats include giant molecular clouds disturbing the Oort comet cloud and provoking heavy bombardment: a higher exposure to cosmic rays near star forming regions triggering increased cloudiness in Earth atmosphere and ice ages; and the desctruction of Earth's ozone layer posed by supernova explosiosn. We present detailed calculations of the history of spiral arm passages for all 212 solar-type stars nearer than 20 parsecs, including the total time spent inside armsin the last 500 Myr, when the spiral arm position can be traced with good accuracy. We found that there is a large diversity of stellar orbits in the solar neighborhood, and the time fraction spent inside spiral arms can vary from a few percent to nearly half the time. The Sun, despite its proximity to the galactic co-rotation radius, has exceptionally low eccentricity and a low vertical velocity component, and therefore spends 30% of its lifetime crossing the spiral arms, more than most nearby stars. We discuss the possible implications of this fact to the long-term habitability of the Earth, and possible correlations of the Sun's passage through the spiral arms with the five great mass extinctions of the Earth's biosphere from the Late Ordovician to the Cretaceous-Tertiary.

Parametric study of retangular patch antenna using denim textile material

—This paper presents a textile patch antenna designed for WBAN applications at 2.45 GHz ISM band. The antenna uses denim as substrate and conductive fabric for the ground plane and radiator layers. The main purpose of this paper is to analyze the influence of typical deviation of denim properties and patch radiator dimensions on the performance of the antenna. The parameters considered in the analysis are the relative permittivity and thickness of denim and the width and length of the rectangular patch radiator. The dependence of the central operation frequency of the antenna on those parameters was studied using the antenna reflection coefficient obtained from EM simulations. Rules of thumb for one-shot design were derived and applied to design a rectangular patch antenna. An antenna prototype was fabricated and measured, demonstrating a 10 dB impedance band of 4.8 % centered at 2.45 GHz, in good agreement with simulated results