Operant measurement of auditory threshold in prelingually deaf users of cochlear implants: II

Two experiments evaluated an operant procedure for establishing stimulus control using auditory and electrical stimuli as a baseline for measuring the electrical current threshold of electrodes implanted in the cochlea. Twenty-one prelingually deaf children, users of cochlear implants, learned a Go/No Go auditory discrimination task (i.e., pressing a button in the presence of the stimulus but not in its absence). When the simple discrimination baseline became stable, the electrical current was manipulated in descending and ascending series according to an adapted staircase method. Thresholds were determined for three electrodes, one in each location in the cochlea (basal, medial, and apical). Stimulus control was maintained within a certain range of decreasing electrical current but was eventually disrupted. Increasing the current recovered stimulus control, thus allowing the determination of a range of electrical currents that could be defined as the threshold. The present study demonstrated the feasibility of the operant procedure combined with a psychophysical method for threshold assessment, thus contributing to the routine fitting and maintenance of cochlear implants within the limitations of a hospital setting.FAPESPConselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)CNP

Caracterización de recubrimientos de hidroxiapatita depositadas sobre la aleación Ti6Al7Nb a través de aspersión térmica a plasma

Hydroxyapatite (HA) coated onto titanium alloys by atmospheric plasma-arc spraying is a promising technique for improving biocompatibility of materials. The tissue adherence to the HA coating increases when compared to the provided by the natural environment of the human body. Hidroxyapatite coating applied to a Ti-6Al-7Nb alloy substrate by plasma spray was characterized morphologically via Scanning Electron Microscopy (SEM) and X-Ray diffraction. X-Ray diffraction results of the HA layer indicated the presence of crystalline HA, amorphous phase and another constituents, like tricalcium phosphate (TCP) and calcium oxide. However, after annealing at a temperature of 600oC there was recristalisation of the amorphous phase and transformation of some of the TCP to HA. SEM results revealed a lamellar morphology which is typical of plasma sprayed surfaces. The HA/alloy interface exhibited some irregularities, however these are not present in the majority of the interfacial area.Peer Reviewe

Estudos soroepidemiológico e molecular de infecção por EV-71 no Estado do Pará, Brasil

In many countries, the Enterovirus 71 (EV-71) Picornaviridae family is associated to hand, foot and mouth disease in addition to acute neurological diseases while in Brazil these viruses are more closely associated to the latter group. The aim of this research was to use the first EV-71 isolate of the Northern region of Brazil in molecular and seroepidemiologic studies. Two (2.2%) out of 88 stool samples (44 cases of AFP), collected from January 1998 to December 2000 were positive for EV-71 isolation (73442/PA/99). Nucleotide sequence of the gen that codifies the VP1 protein showed that isolate 73442/PA/99 was similar to the EV-71 strains belonging to genotype B - more closely identified with EV-71 from North America. Neutralization test with 389 sera samples collected from January 1998 to November 2001, from individuals ranging from 0 to 15 years of age living in the city of Belém, State of Pará showed the following results in relation to isolate 73442/PA/99 and prototype BrCr: a total of 207 individuals (53.2%) had neutralization antibodies to both viruses, 167 (42.9%) had no antibodies and 15 showed the presence of neutralizing antibodies to one of the two viruses. Only 20.2% of the children aged 0 to 3 had neutralizing antibodies to EV-71, indicating that these children were more susceptible to the infection. Both the seroprevalence study and VP1 sequencing were important to demonstrate the spread and the molecular pattern of the EV-71 circulating in the Northern Region of Brazil.Em muitos países, o Enterovírus 71 (EV-71) família Picornaviridae é associado a doença de pé-mão e boca e doenças neurológicas agudas enquanto que no Brasil esse vírus está mais associado às últimas. O objetivo desta pesquisa foi utilizar em estudos moleculares e soroepidemiológicos, o primeiro isolamento de EV-71 obtido na região norte do Brasil. No período de janeiro de 1998 a dezembro de 2000 foram coletadas 88 amostras (44 casos de PFA) de fezes das quais, duas (2,2%) foram positivas para EV-71 (73442/PA/99). A seqüência de nucleotídeos do gen que codifica a proteína VP1 mostrou que o isolado 73442/PA/99 foi similar às cepas de EV-71 pertencentes ao grupo B- mais próxima das norte americanas. Teste de neutralização com 389 amostras de soro colhidas no período de janeiro de 1998 a novembro de 2001, de indivíduos com idade de 0 a 15 anos residentes na cidade de Belém, Estado do Pará mostrou os seguintes resultados em relação ao isolado 73442/PA/99 e ao protótipo BrCr: 207 indivíduos (53,2%) tinham anticorpos neutralizantes para ambos os vírus, 167 (42,9%) não tinham anticorpos e 15 tinham anticorpos para um dos dois vírus. Somente 20,2% das crianças com idade de 0 a 3 anos tinham anticorpos neutralizantes para EV-71, indicando que essas crianças estavam mais suscetíveis à infecção. Tanto o estudo de soroprevalência quanto o de sequenciamento da VP1 foram importantes para demonstrar a propagação e o padrão molecular do EV-71 circulante na região norte do Brasil

Surface modification of bacterial cellulose membranes for microfluidic applications

Although the great advances in medicine, there are still many limitations related to materials that can interact with the human body and its cells. One of the major challenges is developing biocompatible materials that can be used to skin repair treatments, tissue regeneration, inflammation, and wound treatments, among other problems. The most critical step to explore new materials development still remains in the interactive surface cell-contact to different biomaterials1. Bacterial cellulose (BC) has attracted the attention of many in this field due to its advantageous characteristics being biodegradable, non-toxic, non-carcinogenic, and biocompatible with the human body. This polymer could be the future of regenerative medicine and for that, it is necessary to continue exploring their properties and possible treatments that can improve them. The work reports the functionalization of bacterial cellulose (BC) membranes with a view to their application in microfluidic devices for the growth of epidermal cells. Here, is proposed a surface modification with Parylene C deposition by chemical vapor deposition (CVD), and consecutively optimized oxygen (O2) plasma pre-treatment and sulfurhexafluoride (SF6) plasma treatment in a reactive ion etching (RIE) system. Parylene C is a transparent polymer to the naked eye with an excellent permeation barrier for liquid and gaseous types, required for this kind of application. This chemically inert, biocompatible, biostable, flexible, hydrophobic and resistant polymer, has been extensively used for several applications, including for medical devices and implants2. This proposed technique3 produce a surface roughness and enhances the intrinsic hydrophobicity of Parylene-C, by giving not only hydrophobic but superhydrophobic behavior on surface membranes, without altering the material bulk (bacterial cellulose) properties. The best results were obtained by deposition of 10 g of parylene-C, pre-treated with O2 plasma for 10 min, and then SF6 plasma for 1 min. After all the optimization processes a superhydrophobic contact angle was obtained, approximately 155 degrees and remained hydrophobic during 15 days of wettability tests. This work present exceptional results and investigates the ability of the modified bacterial cellulose by integrating them into a chip to support the growth of epidermal cells.info:eu-repo/semantics/publishedVersio

Operant measures of auditory threshold in prelingually deaf children with cochlear implant

Limiares auditivos de crianças surdas pré-linguais usuárias de implante coclear foram avaliados com estimulação elétrica em um dos eletrodos mediais. A avaliação empregou um procedimento operante do tipo go/no go para ensinar uma discriminação simples, evidenciada por uma resposta motora, entre presença e ausência do estímulo auditivo. Estabelecida a linha de base, a manipulação na intensidade do estímulo foi implementada de acordo com o método psicofísico de escada modificado, começando por uma seqüência descendente. Os sete participantes do estudo mostraram perda da precisão no responder sob controle do estímulo quando a intensidade diminuía além de um certo valor e a precisão era recuperada quando a intensidade era novamente aumentada, o que permitiu a identificação de limiares individuais. Os resultados sugerem que o método psicofísico combinado com o procedimento operante pode ser uma alternativa viável para avaliar limiar auditivo de pessoas sem linguagem em situação clínica de regulagem do implante coclear.Auditory thresholds of prelingually deaf children who received cochlear implants were evaluated for the electrical stimulation to one of the medial electrodes. A go/no go operant procedure was used to teach a simple discrimination, indicated by a motor response, between the presence versus the absence of an auditory stimulus. Simple discrimination was used as a baseline upon which the electrical stimulus's intensity was manipulated in a decreasing sequence followed by an increasing sequence, according to a modified psychophysical staircase method. The accuracy of responding in the presence of the electrical stimulus was reduced for all seven participants when the stimulus intensity decreased bellow a certain value and was recovered when the stimulus intensity was increased to the previous level. The experimental design allowed reliable identification of individual thresholds. The results suggest that the psychophysical paradigm in combination with the operant procedure might be useful for the evaluation of the auditory threshold for purposes of cochlear implant fitting in clinical settings.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq

Evaluation of hays produced with Andropogon gayanus grass at different ages using semi - automated in vitro gas production technique

Objetivou-se avaliar o feno da Andropogon gayanus pela técnica in vitro semi-automática de produção de gases. O delineamento estatístico adotado foi o de blocos ao acaso com parcelas subdivididas, sendo as três idades de corte (56, 84 e 112 dias) as parcelas, os inóculos ruminais os blocos, e os tempos de leitura de produção de gases as sub-parcelas. A degradabilidade da matéria seca foi medida nos tempos de 6,12, 24, 48 e 96 horas. As maiores produções (p>0,05) acumuladas de gases foram obtidas com os fenos colhidos aos 56 e 84 dias com 195,1 e 189,4 mL/g de MS respectivamente. Dentre as três idades avaliadas, recomenda-se o feno colhido aos 56 dias de crescimento.In this study were utilized Andropogon gayanus hays produced at different ages of growth (56, 84 and 112 days) for assay of degradability of in vitro dry matter using semi-automated in vitro gas production technique. The statistical design was randomized blocks with split plots. The ages of growth were parcels and degradation time (6, 12, 24, 48 and 96 hours) were subparcels, with five blocks. The observed results indicated that the best hay of A. gayanus are obtained from plants cutted in between 56 days of growth.Facultad de Ciencias Agrarias y Forestale

Evaluation of hays produced with Andropogon gayanus grass at different ages using semi - automated in vitro gas production technique

Objetivou-se avaliar o feno da Andropogon gayanus pela técnica in vitro semi-automática de produção de gases. O delineamento estatístico adotado foi o de blocos ao acaso com parcelas subdivididas, sendo as três idades de corte (56, 84 e 112 dias) as parcelas, os inóculos ruminais os blocos, e os tempos de leitura de produção de gases as sub-parcelas. A degradabilidade da matéria seca foi medida nos tempos de 6,12, 24, 48 e 96 horas. As maiores produções (p>0,05) acumuladas de gases foram obtidas com os fenos colhidos aos 56 e 84 dias com 195,1 e 189,4 mL/g de MS respectivamente. Dentre as três idades avaliadas, recomenda-se o feno colhido aos 56 dias de crescimento.In this study were utilized Andropogon gayanus hays produced at different ages of growth (56, 84 and 112 days) for assay of degradability of in vitro dry matter using semi-automated in vitro gas production technique. The statistical design was randomized blocks with split plots. The ages of growth were parcels and degradation time (6, 12, 24, 48 and 96 hours) were subparcels, with five blocks. The observed results indicated that the best hay of A. gayanus are obtained from plants cutted in between 56 days of growth.Facultad de Ciencias Agrarias y Forestale

Evaluation of hays produced with Andropogon gayanus grass at different ages using semi - automated in vitro gas production technique

Objetivou-se avaliar o feno da Andropogon gayanus pela técnica in vitro semi-automática de produção de gases. O delineamento estatístico adotado foi o de blocos ao acaso com parcelas subdivididas, sendo as três idades de corte (56, 84 e 112 dias) as parcelas, os inóculos ruminais os blocos, e os tempos de leitura de produção de gases as sub-parcelas. A degradabilidade da matéria seca foi medida nos tempos de 6,12, 24, 48 e 96 horas. As maiores produções (p>0,05) acumuladas de gases foram obtidas com os fenos colhidos aos 56 e 84 dias com 195,1 e 189,4 mL/g de MS respectivamente. Dentre as três idades avaliadas, recomenda-se o feno colhido aos 56 dias de crescimento.In this study were utilized Andropogon gayanus hays produced at different ages of growth (56, 84 and 112 days) for assay of degradability of in vitro dry matter using semi-automated in vitro gas production technique. The statistical design was randomized blocks with split plots. The ages of growth were parcels and degradation time (6, 12, 24, 48 and 96 hours) were subparcels, with five blocks. The observed results indicated that the best hay of A. gayanus are obtained from plants cutted in between 56 days of growth.Facultad de Ciencias Agrarias y Forestale

Energy partition and methane production in sheep fed with Andropogon Gayanus hays in three different ages

Foi realizado estudo para descrever a partição da energia e produção de metano por ovinos alimentados com fenos do capim Andropogon gayanus colhidos aos 56, 84 e 112 dias de crescimento. Utilizou-se a metodologia da calorimetria indireta para mensuração das perdas de energia e para a determinação da energia digestível (ED), metabolizável (EM) e líquida (EL). O delineamento experimental foi inteiramente casualizado, sendo constituído de três tratamentos e seis repetições. As médias foram comparadas pelo teste Studant-Newman- Keuls (SNK) ao nível de 5% de significância. O feno, cujo material foi colhido aos 56 dias, resultou em maior (P<0,05) consumo de energia digestível (CED) em relação aos materiais fenados com 84 e 112 dias de rebrote. As perdas diárias de energia através da urina, do metano e do incremento calórico não apresentaram diferença (P>0,05) entre os tratamentos. O feno contendo material colhido aos 56 dias apresentou valor de digestibilidade aparente da energia bruta (DAEB) superior (P0,05) entre si. O feno colhido as 56 dias apresentou maior valor de energia digestível e energia metabolizavél em relação aos demais fenos que não diferiram entre si (P>0,05). A produção de metano não variou (P>0,05) entre os tratamentos estudados.A study was conducted to describe the energy partition and methane production by sheep fed grass hay of Andropogon gayanus harvested at 56, 84 and 112 days of growth. We used the methodology of indirect calorimetry to measure energy losses and to determine the digestible energy (DE), metabolizable (ME) and liquid (EL). The experimental design was completely randomized, consisting of three treatments and six replications. Means were compared by Studant -Newman -Keuls (SNK) test at 5 % significance level. Hays was collected at 56 days, resulted in higher (P &lt; 0.05) digestible energy intake (DEI) in relation to hays 84 and 112 days of regrowth. The daily energy losses through urine, methane and heat increment did not differ (P&gt; 0.05) between treatments. Hay containing material collected at 56 days showed apparent digestibility of the gross energy value higher ( P &lt; 0.5) to the other treatments did not differ ( P&gt; 0.05 ) between them. Hay harvested the 56 days had higher digestible energy and metabolizable energy value compared to other hays that did not differ (P&gt; 0.05). The methane production did not change (P&gt; 0.05) between the treatments.Facultad de Ciencias Agrarias y Forestale

Energy partition and methane production in sheep fed with Andropogon Gayanus hays in three different ages

Foi realizado estudo para descrever a partição da energia e produção de metano por ovinos alimentados com fenos do capim Andropogon gayanus colhidos aos 56, 84 e 112 dias de crescimento. Utilizou-se a metodologia da calorimetria indireta para mensuração das perdas de energia e para a determinação da energia digestível (ED), metabolizável (EM) e líquida (EL). O delineamento experimental foi inteiramente casualizado, sendo constituído de três tratamentos e seis repetições. As médias foram comparadas pelo teste Studant-Newman- Keuls (SNK) ao nível de 5% de significância. O feno, cujo material foi colhido aos 56 dias, resultou em maior (P<0,05) consumo de energia digestível (CED) em relação aos materiais fenados com 84 e 112 dias de rebrote. As perdas diárias de energia através da urina, do metano e do incremento calórico não apresentaram diferença (P>0,05) entre os tratamentos. O feno contendo material colhido aos 56 dias apresentou valor de digestibilidade aparente da energia bruta (DAEB) superior (P0,05) entre si. O feno colhido as 56 dias apresentou maior valor de energia digestível e energia metabolizavél em relação aos demais fenos que não diferiram entre si (P>0,05). A produção de metano não variou (P>0,05) entre os tratamentos estudados.A study was conducted to describe the energy partition and methane production by sheep fed grass hay of Andropogon gayanus harvested at 56, 84 and 112 days of growth. We used the methodology of indirect calorimetry to measure energy losses and to determine the digestible energy (DE), metabolizable (ME) and liquid (EL). The experimental design was completely randomized, consisting of three treatments and six replications. Means were compared by Studant -Newman -Keuls (SNK) test at 5 % significance level. Hays was collected at 56 days, resulted in higher (P &lt; 0.05) digestible energy intake (DEI) in relation to hays 84 and 112 days of regrowth. The daily energy losses through urine, methane and heat increment did not differ (P&gt; 0.05) between treatments. Hay containing material collected at 56 days showed apparent digestibility of the gross energy value higher ( P &lt; 0.5) to the other treatments did not differ ( P&gt; 0.05 ) between them. Hay harvested the 56 days had higher digestible energy and metabolizable energy value compared to other hays that did not differ (P&gt; 0.05). The methane production did not change (P&gt; 0.05) between the treatments.Facultad de Ciencias Agrarias y Forestale