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1.
Article | IMSEAR | ID: sea-195739

Résumé

The development of cellular phone system has greatly increased the extent and magnitude of radiofrequency radiation (RFR) exposure. The RFR emitted from mobile phone and mobile phone base stations exerts thermal and non-thermal effects. The short-term and long-term exposure to RFR may have adverse effect on humans as well as animals. Most laboratory studies have indicated a direct link between exposure to RFR and adverse biological effects. Several in vitro studies have reported that RFR induces various types of cancer and DNA or chromosomal damage. On the other hand, some animal studies have not reported adverse effects of this radiation. The present review summarizes information available on the possible effects of RFR on the reproductive health.

2.
Article Dans Anglais | IMSEAR | ID: sea-162923

Résumé

Aim: To investigate increased thermal influence on morphology of Aspergillus carbonarius during RSDA production. Place and Duration of Study: Microbial fermentation Unit, Department of Microbiology, Faculty of Biological sciences, University of Nigeria, between July 2009 and August 2010. Methodology: In shake flask cultures thermal influence on A. carbonarius morphology and productivity investigated. Mycelial morphology was characterised by means of image analysis using as parameters, mean diameter, roughness, circularity and compactness of pellet. Thermal effect on amylase activity, total protein, biomass concentration and pH were also investigated. Results: Shifting the temperature from 27ºC to 37ºC significantly affected the morphological parameters of the pellets, but RSDA activity was not altered. The interesting thing about the morphology is the shearing off of the hairy part of the pellet at an increased temperature and subsequent agglomeration. At 27ºC the RSDA activity increased steadily with an optimum activity of 293U/ml at 96h and subsequently decreased to 75U/ml by the end of the fermentation. At 37ºC a maximum activity of 291U/ml was achieved at 72h of fermentation but this decreased to 87U/ml at the end of fermentation. Higher biomass concentration and total protein were obtained at 37ºC. The pH dropped from an initial of 5.0 to 3.0 and 2.5 for 27ºC and 37ºC temperature conditions respectively. Conclusion: Induced thermal increase resulted to changes in pellet morphology but raw starch digesting amylase activity was not altered.

3.
Fisioter. mov ; 25(4): 857-868, out.-dez. 2012. graf, tab
Article Dans Portugais | LILACS | ID: lil-660508

Résumé

INTRODUÇÃO: O ultrassom (US) terapêutico atua nos tecidos biológicos por meio da vibração, que é capaz de produzir efeitos fisiológicos térmicos e não térmicos. OBJETIVO: Discutir os parâmetros que afetam o aquecimento dos tecidos biológicos, decorrente da aplicação do US. MATERIAIS E MÉTODOS: Efetuou-se levantamento bibliográfico nas bases de pesquisa ISI WEB e SCOPUS. Foram selecionados os artigos, na língua inglesa, que tiveram como ponto central, o estudo da variação da temperatura após a aplicação do US em humanos. RESULTADOS: Foram observadas variações significativas em relação ao aumento de temperatura tecidual. Para a frequência de 3MHz, ocorre um aumento médio de 2,6 ºC nos tecidos superficiais; e para 1MHz, há um aumento médio de 1,7 ºC em tecidos profundos. Há um maior aquecimento do tecido em relação ao tamanho da ERA (área de radiação efetiva), quanto menor o tamanho maior o aquecimento. Também há um aumento da temperatura em relação às intensidades. Intensidades variando entre 0,5 a 3 W/cm² apresentam um acréscimo significativo de temperatura. Em relação à forma de aplicação, o gel proporciona melhor acoplamento, gerando maior aquecimento com um tempo de aplicação de cinco minutos - o tempo de aplicação deve ser adequado à área de tratamento e à densidade de potência. Entretanto, a velocidade de aplicação parece não modificar o aquecimento até 7-8 cm/s, mesmo que dispositivos diferentes aqueçam em níveis diferentes. CONCLUSÃO: Os parâmetros para a aplicação do US devem ser controlados e ajustados para produzir o aquecimento profundo dos tecidos considerando a variação entre dispositivos.


INTRODUCTION: The therapeutic ultrasound act in biological tissues by means of vibration can produce physiological effects of thermal and non-thermal. OBJECTIVE: To discuss the parameters that affect the heating of biological tissues by ultrasound. MATERIALS AND METHODS: We conducted a literature research based on ISI Web and SCOPUS database. We selected the articles in the English language that have studied the temperature variation after the application of ultrasound in humans. RESULTS: There are significant variations related to tissue-temperature rise. For the 3MHz ultrasound, there is an average increase of 2.6 ºC in superficial tissues, and to the 1MHz US, there is an average increase of 1.7 ºC in deep tissues. There is a higher heating of the treated tissue when an area twice the ERA (effective radiating area) size, the shorter the higher the heating, there is an increase in temperature relative intensities. Intensities ranging from 0.5 to 3 W/cm² have a significant increase in temperature. Regarding the mode of application, the gel provides an improved coupling, generating more heat with an application time of five minutes - the application time depends on the treatment area and power density. However, the speed of application appears to modify the heating up to 7-8 cm/s. Also, different commercial devices produce heat differently. CONCLUSION: Parameters for ultrasound application must be controlled and adjusted to generate deep heating of tissues considering that it may vary among devices.


Sujets)
Température , Science des ultrasons
4.
Chinese Journal of Medical Imaging Technology ; (12): 1896-1898, 2009.
Article Dans Chinois | WPRIM | ID: wpr-472195

Résumé

High intensity focused ultrasound (HIFU) is a new and exciting medical treatment. Cavitation is the focus in the field of HIFU research. Cavitation and the relationship between cavitation, echo and the thermal effects of HIFU treatment were reviewed in this article.

5.
Article Dans Anglais | IMSEAR | ID: sea-137798

Résumé

A cross-over study was conducted on the changes in the wall and air temperatures of the single-wall infant incubator, as well as infant abdominal skin and rectal temperatures, when the incubator is covered a blanket. Sixteen clinically stable infants being nursed in incubators, nine males and seven females with a mean birth weight of 1,905 g (rang 1,100 to 3,100 g) and a mean age at the time of study of 17.6 days (range 3 to 48 days), were randomly assigned to two orders of study conditions. Significant temperature increases were recorded when the incubator were covered, compared with periods without a blanket : 0.62oC for the abdominal skin incubator wall (p = 0.000); 0.57oC for the air temperature (p = 0.001); 0.11oC for the abdominal skin temperature (p = 0.002); and 0.12oC for the rectal temperature (p = 0.000). The study showed that covering the single-wall infant incubator with a blanket can prevent the incubator wall from heat loss by natural and forced convection, and the infant from heat loss by natural convection and radiation.

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