Ototoxicity and otoprotection in the inner ear of guinea pigs using gentamicin and amikacin: ultrastructural and functional aspects

A ototoxicidade ainda é um desafio para medicina. A descoberta dos mecanismos endógenos autoprotetores das células ciliadas externas associados a métodos de avaliação funcional e ultra-estrutural das mesmas abriu nova perspectiva no entendimento e controle destes mecanismos. OBJETIVO: O trabalho objetivou determinar se subdoses de gentamicina protegia contra ototoxicidade da amicacina baseado nestes mecanismos e determinar se a amplitude das emissões otoacústicas teria correlação com grau de integridade das células ciliadas. MATERIAL E MÉTODO: Estudo experimental. Utilizando 31 cobaias, administrou-se soro fisiológico, gentamicina e amicacina, isoladamente e associadas, via intramuscular, por 12, 30 e 42 dias. Pesquisa de emissões otoacústicas foi realizada no início e final do experimento, comparado com estudo da integridade coclear, por microscopia eletrônica. RESULTADOS: Subdoses de gentamicina não protegeram a orelha interna contra toxicidade da amicacina; diminuições da amplitude das emissões otoacústicas apresentaram forte correlação com aumento de lesões das células ciliadas. CONCLUSÃO: Os achados contribuem para o entendimento dos mecanismos de ototoxicidade e otoproteção da orelha interna. A determinação da correlação entre amplitude de emissões e integridade celular tem grande importância no acompanhamento das lesões de células ciliadas, com possível aplicação no monitoramento de ototoxicidade por drogas em humanos.Ototoxicity is still a challenge to medicine. The discovery of self-protecting endogenous mechanisms of the outer hair cells associated with their functional and ultra-structural assessment methods has opened new horizons in the understanding and controlling of these mechanisms. AIM: this paper aimed at establishing whether or not underdoses of gentamicin could protect the inner ear against the harmful effects of amikacin, based on these protection mechanisms and determine if the otoacoustic emission amplitudes could be associated with the level of hair cell integrity. MATERIALS AND METHODS: Experimental study. We used 31 guinea pigs. They were injected with saline solution, gentamicin and amikacin, alone and in combinations -intramuscular injections - during 12, 30 and 42 days. The otoacoustic emissions were recorded in the beginning and at the end of the experiment, comparing it with the cochlear integrity study carried out by electron microscopy. RESULTS: gentamicin underdoses did not protect the inner ear against amikacin toxicity; the reduction in otoacoustic emissions was strongly associated with an increase in hair cell lesions. CONCLUSION: these findings help understand inner ear otoprotection and ototoxicity. Establishing the correlation between the emissions amplitude an cell integrity plays an important role in the follow up of hair cell damage, with possible monitoring of ototoxicity caused by drugs in humans

Compreender Ricoeur

PELLAUER, David. Compreender Ricoeur. Tradução de Marcus Penchel. São Paulo: Vozes, 2009

Compreender Ricoeur

PELLAUER, David. Compreender Ricoeur. Tradução de Marcus Penchel. São Paulo: Vozes, 2009

When Politicians Talk About Politics: Identifying Political Tweets of Brazilian Congressmen

Since June 2013, when Brazil faced the largest and most significant mass protests in a generation, a political crisis is in course. In midst of this crisis, Brazilian politicians use social media to communicate with the electorate in order to retain or to grow their political capital. The problem is that many controversial topics are in course and deputies may prefer to avoid such themes in their messages. To characterize this behavior, we propose a method to accurately identify political and non-political tweets independently of the deputy who posted it and of the time it was posted. Moreover, we collected tweets of all congressmen who were active on Twitter and worked in the Brazilian parliament from October 2013 to October 2017. To evaluate our method, we used word clouds and a topic model to identify the main political and non-political latent topics in parliamentarian tweets. Both results indicate that our proposal is able to accurately distinguish political from non-political tweets. Moreover, our analyses revealed a striking fact: more than half of the messages posted by Brazilian deputies are non-political.Comment: 4 pages, 7 figures, 2 table

ESTUDO DO MOMENTO ÓTIMO DE REFORMA PARA POVOAMENTOS DE Eucalyptus spp – O CASO DA REDUÇÃO DOS CUSTOS

Os objetivos deste trabalho foram: a) propor e verificar a eficiência de um modelo matemático que permita estudar os efeitos do progresso tecnológico (redução dos custos) sobre a época ótima de substituir povoamentos de Eucalyptus spp; b) determinar a rotação florestal de um povoamento de Eucalyptus spp; c) verificar qual seria o momento de substituir se as receitas estivessem constantes desde o início dos incentivos fiscais, ou seja, na década de 60, e, d) projetar o momento de substituir o povoamento no futuro, considerando os custos decrescentes e a produtividade constante a valores de hoje. Utilizou-se a Função Gompertz para o cálculo da produção de madeira. O critério utilizado para a avaliação econômica da viabilidade dos projetos foi o Valor Presente Líquido. O modelo proposto permitiu calcular o efeito do progresso tecnológico nos custos no período entre 1960 e 2000 e projetar os valores dos custos para o período entre 2000 e 2040. Concluiu-se que: a) a rotação, com valores atuais, encontra-se, em 7 anos, mantidas as receitas da década de 60; b) o momento ótimo de reforma estaria em seis cortes; c) o modelo mostrou-se eficiente para estimativas em um horizonte de até 40 anos; o estudo da cadeia de substituição mostrou que as épocas ótimas de reforma caíram ao longo dos anos, de seis cortes na década de 60, três na década de 80 e dois atualmente; a tendência é permanecer nos dois cortes passando a três com um pequeno aumento na produtividade das talhadias

Study of the optimal time for replacement of Eucalyptus spp. plantations – the case of costs reduction

Os objetivos deste trabalho foram: a) propor e verificar a eficiência de um modelo matemático que permita estudar os efeitos do progresso tecnológico(redução dos custos) sobre a época ótima de substituir povoamentos de Eucalyptus spp; b)determinar a rotação florestal de um povoamento de Eucalyptus spp; c) verificar qual seria o momento de substituir se as receitas estivessem constantes desde o início dos incentivos fiscais, ou seja, na década de 60, e, d)projetar o momento de substituir o povoamento no futuro, considerando os custos decrescentes e a produtividade constante a valores de hoje. Utilizou-se a Função Gompertz para o cálculo da produção de madeira. O critério utilizado para a avaliação econômica da viabilidade dos projetos foi o Valor Presente Líquido. O modelo proposto permitiu calcular o efeito do progresso tecnológico nos custos no período entre 1960 e 2000 e projetar os valores dos custos para o período entre 2000 e 2040. Concluiu-se que: a) a rotaçã o, com valores atuais, encontra-se, em 7 anos, mantidas as receitas da década de 60; b) o momento ótimo de reforma estaria em seis cortes; c) o modelo mostrou-se eficiente para estimativas em um horizonte de até 40 anos; o estudo da cadeia de substituição mostrou que as épocas ótimas de reforma caíram ao longo dos anos, de seis cortes na década de 60, três na década de 80 e dois atualmente; atendência é permanecer nos dois cortes passando a três com um pequeno. ____________________________________________________________________________________ ABSTRACTThe objectives of this work were: a) to study the effects of cost reduction on the optimal replacement time of Eucalyptus plantations; b) to determine rotation age, keeping income constant and cost decreasing overtime; c) to verify the efficiency of a mathematical model for modelling technological progress effects; d) to verify which would be the substitution cicle if the income had been constant since the sixties; and, e) to project substitution time in the future, considering decreasing cost and constant income at today’ s values. Data from forest enterprises located in the Cerrado region were used. The Gompertz Function was employed to calculate timber yield. The economical evaluation method used was the Present Net Worth. The proposed model allowed calculating technological progress effect on costs in the 1960 - 2000 period and to project the cost values for the 2000 – 2040 period. It was concluded that: a)the rotation, with current values is 7 years; b) maintaining the income at the sixties levels, the optimal substitution cycle would be at 6 cuttings; c) the model proved to be efficient for estimates of up 40 years horizon; and, d) the substitution chain showed that the optimal substitution cycle went down along the years, from 6 cuttings in the sixties, 3 in the eighties and 2 currently; the future tendency is to stick with 2 cuttings, reaching 3 cuttings with increase in the coppice yields

Biomimetics as a strategy for the development of bioinspired structures for energy absorption based on fruits

This review seeks to update our knowledge about fruits, your structures, your materials for development of bio-inspired products, and your respective applications in-volving energy absorption, and shock dissipation. In nature, we will find a multitude of biological structure that performs the function of protection and crashworthiness. This study focuses on one of the biologically most important functions found in the natural packaging –that consists of the direct or indirect protection against mechanical damage or other negative environmental influences that involving crashworthiness– as well as energy absorption. Through of the systematic literature review, which includes all peer-reviewed research, documents that are relevant to the objective to ensure a comprehensive search were selected 21 research studies. Three research databases were identified: (I) web of Sci-ence, (II) Scopus, and (III) Science Direct. Only primary empirical studies were included. The review identified several situations where Biomimetics and Bio-inspiration method-ology are introduced for improvements and solving technological problems by analyzing, abstracting, adapting, and transposing biological principles, into the technical world. The results indicated that the structures based on fruits could improve the structure’s effi-ciency that has the role of providing an effective bio-inspired absorber for a multitude of product designs. Although there are several studies, more research is needed for use of new technologies and new settings to ensure recommendations that can implement the improvement of the development of design bio-inspired

USING TECHNOLOGY DRIVEN FLIPPED CLASS TO PROMOTE ACTIVE LEARNING IN ACCOUNTING

The flipped classroom is a pedagogical model that occurs when students become active learners and study the class content previously as homework. The new generation of students is more engaged with the intensive use of technology and increased collaborative learning. However, there are few studies about the flipped classroom method which uses technology and active methodologies resulting in better engagement and improvement in student performance. This study aims to investigate the performance gain during the class and the students' perception of the use of the enhanced flipped classroom approach. Two accounting undergraduate classes with the same curriculum content, attending the research methodology course, had four classes using the flipped classroom approach. The sample consisted of 78 students from a public university in Brazil. Each flipped class began with a homework assignment; in addition, students should post and vote for their difficulties related to the assignment before class. In each class, there were two tests based on the most voted questions and collaborative activities between them without the help of the professor. The test results showed that in all flipped classes, there was a vast improvement after the collaborative activity being included as part of the process of knowledge construction. In addition, a survey was conducted with students and the results showed that they approve the use of enhanced flipped classroom as an appropriate teaching strategy. Universities should encourage the use of active methodologies and technological resources as a means of improving the educational processes