RESUMEN
Three events for the decay K+-->pi+ nunu have been observed in the pion momentum region below the K+-->pi+pi0 peak, 140 < Ppi < 199 MeV/c, with an estimated background of 0.93+/-0.17(stat.) -0.24+0.32(syst.) events. Combining this observation with previously reported results yields a branching ratio of B(K+-->pi+ nunu) = (1.73(-1.05)+1.15) x 10(-10) consistent with the standard model prediction.
RESUMEN
An additional event near the upper kinematic limit for K+-->pi(+)nunu; has been observed by experiment E949 at Brookhaven National Laboratory. Combining previously reported and new data, the branching ratio is B(K+-->pi(+)nunu;)=(1.47(+1.30)(-0.89))x10(-10) based on three events observed in the pion momentum region 211
RESUMEN
Additional evidence for the rare kaon decay K+-->pi+nu(nu) has been found in a new data set with comparable sensitivity to the previously reported result. One new event was observed in the pion momentum region examined, 211
RESUMEN
The possibility of separating cells on the basis of levels of antigen expression was explored in a model system using fixed erythrocytes and high gradient magnetic separation (HGMS). Fixed human erythrocytes were labelled to varying degrees with tetrameric monoclonal antibody complexes specific for both dextran and glycophorin A-M. The cells were then mixed and incubated with dextran iron particles prior to magnetic separation. The small size of the dextran iron particles (less than 0.2 microns) resulted in quantitative magnetic labelling of cells as shown using fluoresceinated anti-dextran antibodies and flow cytometry. The relationships between the initial percentage of labelled cells, cell recovery, non-specific entrapment of unlabelled cells, the purity of the removed fraction, the degree of antigen expression and separation conditions (flow rate and field strength) were determined and used to establish separation conditions that allowed recovery of cells that differ only in the degree of antibody labelling.