Enhanced response of the fricke solution doped with hematoporphyrin under X-rays irradiation

The vials filled with Fricke solutions were doped with increasing concentrations of Photogem®, used in photodynamic therapy. These vials were then irradiated with low-energy X-rays with doses ranging from 5 to 20 Gy. The conventional Fricke solution was also irradiated with the same doses. The concentration of ferric ions for the Fricke and doped-Fricke irradiated solutions were measured in a spectrophotometer at 220 to 340 nm. The results showed that there was an enhancement in the response of the doped-Fricke solution, which was proportional to the concentration of the photosensitizer. The use of such procedure for studying the radiosensitizing property of photosensitizers based on the production of free radicals is also discussed.Tubos de ensaio foram preenchidos com a solução Fricke dopada com Fotogem® em concentrações crescentes; essa hemotoporfirina é utilizada na terapia fotodinâmica. Esses tubos foram irradiados com doses de 5 a 20 Gy. A solução Fricke convencional também foi irradiada com as mesmas doses. As concentrações de íons férricos nas soluções Fricke convencional e dopadas irradiadas foram medidas num espectrofotômetro com comprimento de onda entre 220 e 340 nm. Os resultados mostraram que quando comparado o Fricke convencional com o Fricke dopado irradiado, as amostras dopadas demonstraram um aumento na resposta da dose absorvida que é proporcional a concentração do Photogem® na solução Fricke. Concluímos que esse procedimento pode ser utilizado para propósitos de dosimetria na terapia com radiossensibilizadores

Method of 210Pb geochronological to estimate sedimentation rate in water reservoir in the Brazilian semiarid region

Dams are important reservoirs in semiarid regions providing the needs of the population and agricultural activities in an area in which intermittent rivers predominate. These reservoirs are subject to erosion processes that can cause sedimentation and affect the quality of the water in them. The method of dating sediments using 210Pb is well known and is used to establish a precise chronology of the sediments in places where abrupt changes in sedimentation conditions do not occur. The work aims to determine the sedimentation rate in five main tributary points of the dam located in the semiarid region of the state of Pernambuco, Brazil, using the geochronologic dating of the sediments by measuring 210Pb activity. The method used was the Constant Rate of Supply (CRS) model. Dating coincides with the date of the conclusion of the construction of the dam. The sedimentation rate grew with the increase in depth and presented a decline in both the rate and flow of the sediments over time. The most recent results presented a decrease in sedimentation rates. The greatest occurrence of the sedimentation rate was identified at points located at the entrance of the dam, which could be justified by the reduction in the average speed of final drainage due to the existence of the reservoir itself.Dams are important reservoirs in semiarid regions providing the needs of the population and agricultural activities in an area in which intermittent rivers predominate. These reservoirs are subject to erosion processes that can cause sedimentation and affect the quality of the water in them. The method of dating sediments using 210Pb is well known and is used to establish a precise chronology of the sediments in places where abrupt changes in sedimentation conditions do not occur. The study aims to determine the sedimentation rate in five main tributary points of the dam located in the semiarid region of the state of Pernambuco, Brazil, using the geochronologic dating of the sediments by measuring 210Pb activity. The method used was the Constant Rate of Supply (CRS) model. Dating coincides with the date of the conclusion of the construction of the dam. The sedimentation rate grew with the increase in depth and presented a decline in the sediments’ rate and flow over time. The most recent results presented a decrease in sedimentation rates. The highest sedimentation rates were identified at points located at the entrance to the dam, which could be explained by the reduction in the average drainage velocity due to the existence of the reservoir itself