Abstract Theoretical and experimental evaluation of people´s exposure to electromagnetic radiation due to base stations of mobile telephony located in the city of Soledad, Atlántico (Colombia) was carried out. This was done by calculating the radiation intensity of the antennas and the distance of the exposed person. Experimentally, power density measurements were done at 22 base stations using a broadband radio frequency measurement equipment. A limited set of measured power density values were compared and discussed with the calculated values. The results show that the power density values in each mobile telephone base station are well below the permissible limits to electromagnetic fields in the Colombian and international regulations, 4.5 W/m2 and 9.0 W/m2 for frequencies of 900 MHz and 1800 MHz, respectively.

Resumen Se realizó una evaluación teórica y experimental de la exposición poblacional a la radiación electromagnética debida a estaciones base de telefonía móvil ubicadas en el municipio de Soledad, Atlántico (Colombia). Esto se realizó mediante el cálculo de la intensidad de radiación de las antenas y la distancia de la persona expuesta. Experimentalmente, se realizaron mediciones de densidad de potencia en 22 estaciones base usando un equipo de medición de radiofrecuencia de banda ancha. Un conjunto limitado de valores de densidad de potencia medido fue comparado y discutido con los valores calculados. Los resultados demuestran que los valores de densidad de potencia en las estaciones base de telefonía móvil se encuentran muy por debajo de los límites permisibles a los campos electromagnéticos de la normatividad colombiana e internacional, 4.5 W/m2 y 9.0 W/m2 para frecuencias de 900 MHz y 1800 MHz, respectivamente.

Uma série de (E)-2-(benzo[d]tiazol-2-il)-3-arilacrilonitrilas foi sintetizada pela condensação de Knoevenagel assistida por microondas, na ausência de solvente, partindo do correspondente 2-(benzo[d]tiazo-2-il)acetonitrila e aldeídos aromáticos, contendo tanto grupos doadores de elétrons, como retiradores. Os tempos de reação foram consideravelmente curtos e os produtos, obtidos em rendimentos moderados (50-75%) e boa pureza. A configuração da dupla ligação da acrilonitrila não pôde ser estabelecida por métodos comuns de RMN. No entanto, estudos teóricos sugerem que nesses compostos o isômero E é mais estável do que o Z, o que está de acordo com algumas evidências experimentais.

A series of (E)-2-(benzo[d]thiazol-2-yl)-3-arylacrylonitriles was synthesized by microwave assisted Knoevenagel condensation under solvent-free conditions from the corresponding 2-(benzo[d]thiazol-2-yl)acetonitrile and aromatic aldehydes with electrondonating/electron-withdrawing groups. The reaction times were considerably short and the products obtained in moderate yields (50 to 75%) and good purity. The configuration of the acrylonitrile double bond could not be established by regular NMR methods. However, theoretical studies suggest that the E isomer is more stable than Z, which is in good agreement with some experimental evidences.