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.

A common standardized methodology for the measurement of defence spending

Includes bibliography

A standardized methodology for the measurement of defence spending

Includes bibliography

A new microcontrolled structural health monitoring system based on the electromechanical impedance principle

This article presents a new method to detect damage in structures based on the electromechanical impedance principle. The system follows the variations in the output voltage of piezoelectric transducers and does not compute the impedance itself. The proposed system is portable, autonomous, versatile, and could efficiently replace commercial instruments in different structural health monitoring applications. The identification of damage is performed by simply comparing the variations of root mean square voltage from response signals of piezoelectric transducers, such as lead zirconate titanate patches bonded to the structure, obtained for different frequencies of the excitation signal. The proposed system is not limited by the sampling rate of analog-to-digital converters, dispenses Fourier transform algorithms, and does not require a computer for processing, operating autonomously. A low-cost prototype based on microcontroller and digital synthesizer was built, and experiments were carried out on an aluminum structure and excellent results have been obtained. © The Author(s) 2012.

Environmental light color affects the stress response of Nile tilapia

We investigated the effects of environmental light colors (blue, yellow and white) on the stress responses (measured by changes in ventilatory frequency - VF) of Nile tilapia to confinement. After 7 days of light treatment, the VF was similar for fish in each color. On the 8th day, fish were confined for 15. min. After release, the post-confinement VF was measured six times (first period: 0, 2 and 4. min; second period: 6, 8 and 10. min). Irrespective of the light color treatment, confinement increased the VF to higher levels during the first post-confinement period than during the second one. When color was analyzed, irrespective of time, fish under white light increased their VF post-confinement, and blue light prevented this effect. We conclude that blue light is the preferred color for Nile tilapia in terms of reducing stress. This finding is in contrast to previous choice test studies that indicated that yellow is their preferred color. © 2012 Elsevier GmbH.

Mathematical analysis and simulations involving chemotherapy and surgery on large human tumours under a suitable cell-kill functional response

Dosage and frequency of treatment schedules are important for successful chemotherapy. However, in this work we argue that cell-kill response and tumoral growth should not be seen as separate and therefore are essential in a mathematical cancer model. This paper presents a mathematical model for sequencing of cancer chemotherapy and surgery. Our purpose is to investigate treatments for large human tumours considering a suitable cell-kill dynamics. We use some biological and pharmacological data in a numerical approach, where drug administration occurs in cycles (periodic infusion) and surgery is performed instantaneously. Moreover, we also present an analysis of stability for a chemotherapeutic model with continuous drug administration. According to Norton & Simon [22], our results indicate that chemotherapy is less eficient in treating tumours that have reached a plateau level of growing and that a combination with surgical treatment can provide better outcomes.

Branchial O2 chemoreceptors in Nile tilapia Oreochromis niloticus: Control of cardiorespiratory function in response to hypoxia

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Age Affects Exercise-Induced Improvements in Heart Rate Response to Exercise

The aim of the present study was to analyze the effects of age on cardiorespiratory fitness (CRF), muscle strength and heart rate (HR) response to exercise adaptation in women in response to a long-term twice-weekly combined aerobic and resistance exercise program. 85 sedentary women, divided into young (YG; n=22, 30.3±6.2 years), early middle-aged (EMG; n=28, 44.1±2.5 years), late middle-aged (LMG; n=20, 56.7±3.5 years) and older (OG; n=15, 71.4±6.9 years) groups, had their CRF, muscle strength (1-repetition maximum test) and HR response to exercise (graded exercise test) measured before and after 12 months of combined exercise training. Exercise training improved CRF and muscle strength in all age groups (P<0.05), and no significant differences were observed between groups. Exercise training also improved resting HR and recovery HR in YG and EMG (P<0.05), but not in LMG and OG. Maximal HR did not change in any group. Combined aerobic and resistance training at a frequency of 2 days/week improves CRF and muscle strength throughout the lifespan. However, exercise-induced improvements in the HR recovery response to exercise may be impaired in late middle-aged and older women. © Georg Thieme Verlag KG.

Análise da atividade enzimática de quitotriosidase como um marcador para a malária vivax: abordagens bioquímicas e moleculares

A quitotriosidase foi a primeira quitinase humana descrita e sua função fisiológica ainda não está totalmente esclarecida. Entretanto, diversos estudos têm demonstrado sua participação como componente na resposta imune humana. Uma duplicação de 24pb no éxon 10 do gene chit1 promove uma mudança na matriz de leitura do RNAm com deleção de 87 nucleotídeos. Esta alteração produzirá uma proteína sem atividade catalítica. Esta condição é chamada de deficiência de quitotriosidase e apresenta uma frequência aproximada de 6% de homozigose para a duplicação em diferentes grupos étnicos. A malária é uma parasitose endêmica da região amazônica causada por protozoários do gênero Plasmodium cujos sintomas incluem febre, dor de cabeça e vômitos, o que induz a uma resposta imunológica característica com o objetivo de combater essa patologia. Os objetivos deste trabalho foram avaliar o comportamento da enzima quitotriosidase em pacientes acometidos por malária no estado do Pará e determinar a frequência da duplicação de 24pb no gene da quitotriosidase em uma amostra representativa. Foi realizada dosagem de quitotriosidase em 100 indivíduos sadios e 47 pacientes com malária para a análise. A análise molecular da duplicação de 24 pb foi realizada em 100 voluntários através de protocolo que incluiu as técnicas de extração de DNA, PCR e depois visualização em gel de agarose 2,5% para verificação dos fragmentos normais (homozigoto normal: 195pb) e com a duplicação de 24pb (homozigoto mutante: 219pb; heterozigoto: 219pb e 195pb). Este trabalho descreveu pela primeira vez na literatura científica a elevação dos níveis plasmáticos de quitotriosidase em pacientes acometidos por malária vivax em comparação com um grupo de indivíduos sadios. Não houve associação entre a parasitemia e os níveis plasmáticos de quitotriosidase nos pacientes com Malária. A análise molecular apresentou uma frequência de 72% de indivíduos homozigotos normais, 24% de indivíduos heterozigotos e 4% de homozigotos mutantes para duplicação de 24 pb. As frequências alélicas ficaram em torno de 84% para o alelo selvagem e 16% para o alelo mutante. Não foi encontrada correlação entre o genótipo e o fenótipo bioquímico (representado pelos níveis de quitotriosidase) no grupo controle.

Deconvolução de perfis de poços através do ajuste de energia

As medidas de resistividade são de fundamental importância para o cálculo da saturação de óleo em reservatórios potencialmente produtores. A combinação das medidas de resistividade rasa e profunda permite a obtenção dos parâmetros R_t, R_xo e d_i. Mas, em reservatórios complexos existem dificuldades em se obter leituras confiáveis de R_t, devido à baixa resolução vertical das ferramentas de investigação profunda. Em reservatórios laminados, por exemplo, as leituras obtidas pela ferramenta de indução profunda (ILD) podem levar a uma interpretação errônea das mesmas, levando a acreditar que as medidas obtidas do perfil referem-se a uma única camada. Este problema pode ser em parte resolvido através de uma metodologia que melhore a resolução vertical dos perfis de investigação profunda, valendo-se do uso de informações obtidas de um perfil de alta resolução vertical, i.e; a curva de resistividade rasa. Uma abordagem neste sentido seria usar um perfil de alta resolução que apresente uma boa correlação com o perfil de investigação profunda. Esta correlação pode ser melhor avaliada se aplicarmos um filtro no perfil de alta resolução, de tal forma que o perfil resultante tenha teoricamente a mesma resolução vertical do perfil de baixa resolução. A obtenção deste filtro, porém, recai na premissa de que as funções respostas verticais para as ferramentas de alta e baixa resolução são disponíveis, o que não ocorre na prática. Este trabalho se propõe mostrar uma nova abordagem onde o filtro pode ser obtido a partir de um tratamento no domínio da freqüência. Tal tratamento visa igualar a energia espectral do perfil de alta resolução à energia espectral do perfil de baixa resolução tendo como base o Teorema de Parseval. Será mostrado que a resolução vertical depende fundamentalmente da energia espectral do perfil em questão. A seguir, uma regressão linear é aplicada sobre os perfis de alta resolução filtrado e de baixa resolução. Para cada ponto amostrado dos perfis, uma rotina de minimização é aplicada visando escolher o melhor intervalo de correlação entre os perfis. Finalmente, um fator de correção é aplicado sobre cada ponto do perfil de baixa resolução. Os resultados obtidos com os perfis de indução são promissores, demonstrando a eficácia da abordagem e mesmo quando aplicada em perfis com diferentes propriedades petrofísicas, a metodologia funcionou satisfatoriamente, sem danificar os perfis originais.

Genetic and biochemical markers of hydroxyurea therapeutic response in sickle cell anemia

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Measurement of Wave Attenuation in Buried Plastic Water Distribution Pipes

Leaks in pipes are a common issue encountered in the water industry. Acoustic methods are generally successful in finding and locating leaks in metallic pipes, however, they are less effective when applied to plastic pipes. This is because leak-noise signals are heavily attenuated due to high damping in the pipe-wall and sound radiation into the soil. As result, high frequency leak noise does not travel long distances. To determine how far leak noise may travel in a pipe at any frequency, the attenuation of the wave responsible for leak noise propagation should be known. In this paper a new method to estimate this is described. The method is then applied to some measurements made on a bespoke pipe-test rig in the UK, and the results are compared with theoretical predictions.

Measurement of Radiant Energy using Pyroelectric Polymer/Ceramic Composite

Monitoring non-ionizing radiant energy is increasingly demanded for many applications such as automobile, biomedical and security system. Thermal type infrared (IR) sensors can operate at room temperature and pyroelectric materials have high sensitivity and accuracy for that application. Working as thermal transducer pyroelectric sensor converts the non-quantified thermal flux into the output measurable quantity of electrical charge, voltage or current. In the present study the composite made of poly(vinylidene fluoride) -PVDF and lead zirconate titanate (PZT) partially recovered with polyaniline (PAni) conductor polymer has been used as sensor element. The pyroelectric coefficient p(T) was obtained by measuring the pyroelectric reversible current, i.e., measuring the thermally stimulated depolarization current (TSDC) after removing all irreversible contribution to the current such as injected charge during polarization of the sample. To analyze the sensing property of the pyroelectric material, the sensor is irradiated by a high power light source (halogen lamp of 250 W) that is chopped providing a modulated radiation. A device assembled in the laboratory is used to change the light intensity sensor, an aluminum strip having openings with diameters ranging from 1 to 10 mm incremented by one millimeter. The sensor element is assembled between two electrodes while its frontal surface is painted black ink to maximize the light absorption. The signal from the sensor is measured by a Lock-In amplifier model SR530 -Stanford Research Systems. The behavior of the output voltage for an input power at several frequencies for PZT-PAni/PVDF (30/ 70 vol%) composite follows the inverse power law (1/ f) and the linearity can be observed in the frequency range used.

Leptin into the ventrolateral medulla facilitates chemorespiratory response in leptin-deficient (ob/ob) mice

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

The first frequency of cantilevered bars with geometric effect: a mathematical and experimental evaluation

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)