Paulo Crespo

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Gentamicin-induced changes in ionic composition in the otolithic membrane of adult OF1 mice were evaluated in the gelatinous layers of the saccule and utricle by quantitative electron probe X-ray microanalysis. The otolithic membranes were plunge-frozen and freeze-dried to prevent the redistribution of elements. Quantitative analysis was carried out with an(More)
The effect of tissue preparation on calcium and potassium weight percent in the otoconial layer in the utricle and saccule was studied in four groups of OF1 mice with electron probe X-ray microanalysis. Glutaraldehyde and freeze-drying, glutaraldehyde and air-drying, air-drying, and cryo-fixation and freeze-drying were compared. Ca and K changed(More)
One of the long-standing problems in carbon-ion therapy is the monitoring of the treatment, i.e. of the delivered dose to a given tissue volume within the patient. Over the last 8 years, in-beam positron emission tomography (PET) has been used at the experimental carbon ion treatment facility at the Gesellschaft fur Schwerionenforschung (GSI) Darmstadt and(More)
In explosive stellar environments like supernovae, the temperatures are high enough for the production of heavy neutron-deficient nuclei, the so-called p-nuclei. Up to now, the knowledge of the reaction rates of p-nuclei is based on theoretical parameterizations using statistical model calculations. At the bremsstrahlung facility of the superconducting(More)
The therapeutic irradiations of 30 patients in 2000 have been observed by PET. The data verified that the modifications of the treatment planning data base [1] considerably improved the precision of dose localization even in delicate situations of very deep-seated and inhomogeneous target volumes (Fig. 1). However , still unpredictable dose deviations may(More)
The cyclopentenone prostaglandin A1 (PGA1) is an inducer of cell death in cancer cells. However, the mechanism that initiates this cytotoxic response remains elusive. Here we report that PGA1 triggers apoptosis by a process that entails the specific activation of H- and N-Ras isoforms, leading to caspase activation. Cells without H- and N-Ras did not(More)
Precipitation event samples and weekly based water samples from streams and soils were collected in a tropical montane cloud forest catchment for 2 years and analyzed for stable water isotopes in order to understand the effect of sampling frequency in the performance of three lumped-parameter distribution functions (exponential-piston flow, linear-piston(More)
Transcranial magnetic stimulation (TMS) was proposed in 1985. Nevertheless, its wider use in the treatment of several neurologic diseases has been hindered by its inability to stimulate deep-brain regions. This is mainly due to the physical limiting effect arising from the presence of surface discontinuities, particularly between the scalp and air. Here, we(More)
The γ-ray strength function is an important input quantity for the determination of the photoreaction rate and the neutron capture rate for astrophysics as well as for nuclear technologies. To test model predictions, the photoab-sorption cross section of 139 La up to the neutron-separation energy was measured using bremsstrahlung produced at the electron(More)
At the experimental heavy ion therapy facility at the GSI Darmstadt an in-beam PET scanner is operated for quality assurance monitoring simultaneously to the therapeutic irradiation. A fully 3D maximum likelihood expectation maximization (MLEM) reconstruction algorithm has been developed and adapted to the special conditions of in-beam PET [1]. The system(More)