RESUMO
The procedure followed by the Nuclear Metrology Laboratory (LMN) at the IPEN-CNEN/SP, in São Paulo, for the primary standardization of 166Ho is described. The activity of 166Ho was determined by the efficiency extrapolation technique applied to a 4πß(PC)-γ coincidence system using a gas flow proportional counter in 4π geometry coupled to a 76 × 76 mm NaI(Tl) crystal. The results for the γ-rays intensities at 80.57 and 1379.45 keV were 0.0651(11) and 0.00904(11), respectively.
Assuntos
Raios gama , Hólmio/normas , Radioisótopos/normas , Padrões de Referência , Espectrometria gama/normasRESUMO
The Nuclear Metrology Laboratory (LMN) - IPEN, São Paulo, Brazil - developed a Digital Coincidence System (DCS), based on the Coincidence Counting Methodology, in order to improve its capabilities in radionuclide primary-standardization. Digital process is implemented in two steps: data-acquisition (a set of measurements) and offline software data-analysis and calculation. The present work shows the basics of the data-acquisition unit (Software Coincidence System - SCS), describes the DCS' data-analysis process and the initial approaches chosen for the implementation of the software package (Coincidence Analyzing Task - CAT). 152Eu standardization, performed for DCS testing, software expansion and validation, is briefly discussed.
RESUMO
The procedure for the standardization of (59)Fe using a 4π(PC)ß-γ software coincidence system is described. The standardization was performed with an experimental setup consisting of a thin window gas-flow proportional counter (PC) in 4π geometry coupled to a NaI(Tl) scintillator and to a HPGe detector. The data acquisition was carried out by means of a Software Coincidence System (SCS). The beta efficiency was changed by using Collodion films and aluminum foils as external absorbers.
RESUMO
The procedure for determining the (67)Ga disintegration rate by a primary method is described. The proposed triple 4πß-γ coincidence system consists of a thin window gas-flow 4π proportional counter (PC) coupled to a NaI(Tl) scintillator and a HPGe crystal. Independent pulse height and occurrence time information is provided for the three detector outputs by means of a Software Coincidence System. Separate spectrometry measurements with a n-type reversed electrode coaxial Ge detector (REGe) were performed for obtaining gamma-ray emission probabilities per decay. Accurate values of disintegration rate, gamma-ray emission probabilities and the metastable half-life were achieved.
RESUMO
The location of Salmonella typhimurium porins has been found in human monocytes and lymphocytes by means of high resolution autoradiography. The results indicate that traces of porins are frequently visible on ultrathin sections of treated human lymphomonocytes and that they are located especially in the nuclear areas.
Assuntos
Linfócitos/metabolismo , Monócitos/metabolismo , Porinas/metabolismo , Salmonella typhimurium/metabolismo , Adulto , Autorradiografia , Sítios de Ligação , Núcleo Celular/química , Núcleo Celular/metabolismo , Humanos , Linfócitos/química , Linfócitos/ultraestrutura , Microscopia Eletrônica , Monócitos/química , Monócitos/ultraestrutura , Porinas/análiseRESUMO
This study investigates changes in IL-1 alpha, IFN-gamma and IL-4 from mouse splenocytes stimulated with Staphylococcal Protein A (PA), or Toxic Shock Syndrome Toxin-1 (TSST-1), or Streptococcal lysin S (SLS) after exposure to Prolactin (PRL). In the presence of PRL, IL-1 alpha and IFN-gamma induction by PA-stimulated splenocytes was reduced by 74% and 25% respectively. On the other hand, IL-4 release was enormously increased. The ability of TSST-1 to induce IFN-gamma release was decreased by 32% after PRL. IL-1 alpha and IL-4 was unchanged compared to controls. In the presence of PRL, IFN-gamma release from splenocytes stimulated with SLS, was increased by 60%, while no changes were shown in IL-1 alpha and IL-4 release.
