Isolating Informational Masking in Both Pure and Complex Tone Sequences

Objectives: Interference between a target and simultaneous maskers occurs both at the cochlear level through energetic masking and more centrally through informational masking (IM). Hence, quantifying the amount of IM requires a strict control of the energetic component. Presenting target and maskers on different sides (i.e., dichotically) reduces energetic masking but provides listeners with important lateralization cues that also drastically reduce IM. The main purpose of this study (Experiment 1) was to evaluate a "switch" manipulation aiming at restoring most of the IM despite dichotic listening. Experiment 2 was designed to investigate the source of the difficulty induced by this switching dichotic condition.

Design: In Experiment 1, the authors presented 60 normal-hearing young adults with a detection task in which a regularly repeating target was embedded in a randomly varying background masker. The authors evaluated spatial masking release induced by three different dichotic listening conditions in comparison with a diotic baseline. Dichotic stimuli were presented in either a nonswitching or a switching condition. In the latter case, the presentation sides of dichotic target and maskers alternated several times throughout 10 sec sequences. The impact of the number of switches on IM was investigated parametrically, with both pure and complex tone sequences. In Experiment 2, the authors compared performance of 13 young, normal-hearing listeners in a monotic and dichotic version of the rapidly switching condition, using pure-tone sequences.

Results: When target and maskers switched rapidly within sequences, IM was significantly stronger than in nonswitching dichotic sequences and was comparable with the masking effect induced by diotic sequences. Furthermore, Experiment 2 suggests that rapidly switching target and maskers prevent listeners from relying on lateralization cues inherent to the dichotic condition, hence preserving important amounts of IM.

Conclusions: This paradigm thus provides an original tool to isolate IM in signal and maskers having overlapping spectra.

Fluxes of organic contaminants from the river catchment into, through and out of the Humber Estuary, UK

This paper summarises the work done on the distribution and reactivity of organic contaminants (simazine, atrazine, lindane, fluoranthene, pyrene, PCB 77, PCB 118) in the Humber Estuary and associated major rivers, as part of the LOIS programme. The preliminary flux calculations show that the most important contributors of selected organic contaminants were the rivers Trent (45% of simazine, 20% of atrazine), Aire (30% of simazine and 33% of atrazine), Don (36 and 37% of fluoranthene and pyrene) and Ouse (18% of fluoranthene and pyrene). For lindane and PCBs, the Aire and Ouse were the key sources. The water flow in all the rivers shows strong seasonal variations, as do the contaminant concentrations. As a result, the mean daily fluxes of these contaminants displayed a strong seasonality. Annual mean concentrations of simazine and atrazine decreased by more than 50% over the period 1994-1995 in most of the rivers, probably as a result of their restricted use in the UK. Mass balance calculations show that the Humber is a sink for atrazine, lindane, PCB 77 and PCB 118, although the degree of removal is generally much lower for atrazine and lindane than for PCB 77 and PCB 118. Mass balance results also show that the Humber can either be a source of fluoranthene and pyrene (in the suspended particulate phase), or a sink (in the dissolved phase), although overall the Humber acts as sink. The budget exercise represents an attempt to quantify the input and output of selected organic contaminants from catchment to ocean. However, due to limited data and assumptions involved in calculations, the estimates should be considered as an order of magnitude approximation. Further improvement both in resolution and accuracy is required.

Metabolically-inactive glucagon-like peptide-1(9-36)amide confers selective protective actions against post-myocardial infarction remodelling

BACKGROUND: Glucagon-like peptide-1 (GLP-1) therapies are routinely used for glycaemic control in diabetes and their emerging cardiovascular actions have been a major recent research focus. In addition to GLP-1 receptor activation, the metabolically-inactive breakdown product, GLP-1(9-36)amide, also appears to exert notable cardiovascular effects, including protection against acute cardiac ischaemia. Here, we specifically studied the influence of GLP-1(9-36)amide on chronic post-myocardial infarction (MI) remodelling, which is a major driver of heart failure progression.

METHODS: Adult female C57BL/6 J mice were subjected to permanent coronary artery ligation or sham surgery prior to continuous infusion with GLP-1(9-36)amide or vehicle control for 4 weeks.

RESULTS: Infarct size was similar between groups with no effect of GLP-1(9-36)amide on MI-induced cardiac hypertrophy, although modest reduction of in vitro phenylephrine-induced H9c2 cardiomyoblast hypertrophy was observed. Whilst echocardiographic systolic dysfunction post-MI remained unchanged, diastolic dysfunction (decreased mitral valve E/A ratio, increased E wave deceleration rate) was improved by GLP-1(9-36)amide treatment. This was associated with modulation of genes related to extracellular matrix turnover (MMP-2, MMP-9, TIMP-2), although interstitial fibrosis and pro-fibrotic gene expression were unaltered by GLP-1(9-36)amide. Cardiac macrophage infiltration was also reduced by GLP-1(9-36)amide together with pro-inflammatory cytokine expression (IL-1β, IL-6, MCP-1), whilst in vitro studies using RAW264.7 macrophages revealed global potentiation of basal pro-inflammatory and tissue protective cytokines (e.g. IL-1β, TNF-α, IL-10, Fizz1) in the presence of GLP-1(9-36)amide versus exendin-4.

CONCLUSIONS: These data suggest that GLP-1(9-36)amide confers selective protection against post-MI remodelling via preferential preservation of diastolic function, most likely due to modulation of infiltrating macrophages, indicating that this often overlooked GLP-1 breakdown product may exert significant actions in this setting which should be considered in the context of GLP-1 therapy in patients with cardiovascular disease.

Compte rendu: Jannis Androutsopoulos (dir.) (2014), Mediatization and sociolinguistic change, Berlin/Boston, De Gruyter, coll. « Linguae & litterae. Publications of the School of Language & Literature Freiburg Institute for Advanced Studies, 36 », vii-557 p. [ISBN : 978-3-11-034357-1]

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Unesp Ciência, 2012, ano 4, número 36

Revista elaborada pela Assessoria de Comunicação e Imprensa da Reitoria da UNESP

O processo de dádiva de sangue do dador de primeira vez no Hospital do Espírito Santo - Évora, EPE : satisfação e retorno para a dádiva seguinte

RESUMO - Introdução: Com este trabalho, pretendeu-se averiguar em que medida a satisfação no processo de dádiva de sangue afeta o regresso dos dadores que doam pela primeira vez na vida, ou que se apresentaram pela primeira vez no Serviço de sangue do HESE. Material e métodos: Estudo observacional transversal descritivo. Dos dadores com uma única inscrição no período de 2011 a 2012 inclusive, (531+541 dadores) foram retirados os que entretanto completaram 66 anos (idade limite para a dádiva); os que não tinham contacto telefónico válido; e os que tinham morada fora do Distrito de Évora. Os dadores restantes (327 + 330 dadores), foram então inquiridos através de um questionário efetuado telefonicamente para determinar as causas de não regresso. Resultados: Obtiveram-se 360 respostas válidas ao questionário, correspondentes a 50% da amostra com um IC de 95%. Apesar de estar amplamente demonstrado que a satisfação na dádiva contribui decisivamente para o retorno à dádiva seguinte, apenas 12% da amostra referiu não regressar por algum motivo de insatisfação decorrente do processo de dádiva. Evidentemente, o mérito destes resultados é devido à equipa do Serviço de Imunohemoterapia do HESE. Porém uma outra realidade fica aqui patente, os dadores de primeira vez estão a decrescer há vários anos, e destes, os que regressam são cada vez menos. A manter-se esta tendência, a taxa de renovação da bolsa de dadores poderá tornar-se insuficiente para a manutenção da atual bolsa de dadores. Se o HESE conseguisse recuperar para a dádiva metade da amostra de dadores de primeira vez que não regressam, a sua autonomia em termos de consumo de sangue sairia reforçada, com o incremento de proveitos financeiros consequente. Conclusão: Este trabalho concretiza os objetivos a que se propôs, nomeadamente o de produzir conhecimento útil e de suporte à decisão no âmbito da administração hospitalar. O HESE tem agora ao seu dispor, a caraterização dos dadores de primeira vez e a descrição de como se está a processar a renovação da sua bolsa de dadores.

Aquisição Fonético - Fonológica do português europeu dos 18 aos 36 meses

Objetivo: O objetivo deste estudo consistiu na descrição da aquisição fonética e fonológica de crianças falantes do Português Europeu (PE), da região Centro de Portugal Continental, com idades compreendidas entre os [18-­‐36[ meses. Mais especificamente pretendeu-­‐se traçar uma ordem cronológica de aquisição dos fones e verificar quais os processos fonológicos mais utilizados nas 3 faixas etárias ([18-­‐24[, [24-­‐30[, [30-­‐36[ meses). Foi ainda objetivo averiguar se existiam diferenças em relação ao número de fones produzidos adequadamente e ao número de processos fonológicos utilizados entre as faixas etárias e os sexos. Definir a ordem pela qual os fones vão surgindo no discurso da criança, isto é, a sua ordem de aquisição, também foi um objetivo deste estudo. Método: A amostra foi constituída por 69 crianças (2 da faixa etária [18-­‐24[m, 31 dos [24-­‐30[m e 36 dos [30-­‐36[m, de ambos os sexos, que frequentavam 6 creches do distrito de Aveiro. Para recolher os dados recorreu-­‐se a gravações digitais áudio usando as imagens do Teste Fonético-­‐Fonológico-­‐ALPE. Resultados: Na aquisição fonética verificou-­‐se que que a produção de fones aumentou significativamente à medida que a idade avançou. Também foram encontradas diferenças entre as 3 faixas etárias (p<0,05), mas não entre os sexos (p>0,05). Foi ainda possível traçar a ordem cronológica de aquisição de fones: vogais orais < vogais nasais < oclusivas orais < oclusivas nasais < fricativas < líquidas Laterais < líquidas vibrantes. Relativamente à aquisição fonológica não se verificaram diferenças entre as 3 faixas etárias e entre os sexos (p>0,05). Quanto aos processos fonológicos, os mais utilizados foram os de estruturação silábica, nomeadamente a redução de grupo consonântico, palatalização e omissão de consoante final. Conclusão: As conclusões de maior relevo incidem no facto das diferenças nas faixas etárias serem mais notórias para a aquisição fonética do que para a aquisição fonológica. Também se verificou que não existiam diferenças entre os sexos na aquisição fonética-­‐fonológica. Constatou-­‐se que nesta amostra as crianças mais velhas adquiriram mais fones que as crianças das faixas etárias mais precoces.

Connexin-36 contributes to control function of insulin-producing cells.

Connexin-36 (Cx36) is a gap junction protein expressed by the insulin-producing beta-cells. We investigated the contribution of this protein in normal beta-cell function by using a viral gene transfer approach to alter Cx36 content in the insulin-producing line of INS-1E cells and rat pancreatic islets. Transcripts for Cx43, Cx45, and Cx36 were detected by reverse transcriptase-PCR in freshly isolated pancreatic islets, whereas only a transcript for Cx36 was detected in INS-1E cells. After infection with a sense viral vector, which induced de novo Cx36 expression in the Cx-defective HeLa cells we used to control the transgene expression, Western blot, immunofluorescence, and freeze-fracture analysis showed a large increase of Cx36 within INS-1E cell membranes. In contrast, after infection with an antisense vector, Cx36 content was decreased by 80%. Glucose-induced insulin release and insulin content were decreased, whether infected INS-1E cells expressed Cx36 levels that were largely higher or lower than those observed in wild-type control cells. In both cases, basal insulin secretion was unaffected. Comparable observations on basal secretion and insulin content were made in freshly isolated rat pancreatic islets. The data indicate that large changes in Cx36 alter insulin content and, at least in INS-1E cells, also affect glucose-induced insulin release.