A K x-ray-L x-ray coincidence technique previously used to measure the Coster-Kronig probability fi3 has been extended to include determination of the fluorescence yields w2 and w 3 . Removal of experimental errors believed to have generated the scatter in literature data was of particular concern. Measurements were performed for elements with Z = 78, 80, 81, 82, 92 and 96. For Z in the region of 80, excellent agreement with Dirac-Hartree-Slater theory is evident for w 2 and w,; however, f 2 3 is systematically lower than predicted. In contrast, for 2 2 92, the theoretical and experimental values for f23 were in quite good agreement while discrepancies became apparent for w 2 and w g .

The relative performances of fluorescence, oblique incidence reflection and phase contrast imaging techniques have been studied for the purpose of monitoring long-term cellular activity and cell viability of several types of normal and cancerous cells in cultures. Time-lapse movies of live cell imaging of untagged and green fluorescent protein (GFP) tagged cell lines are presented. Oblique incidence reflection microscopy is the simplest and least expensive method to implement, appears to be the least phototoxic to cells, and is recommended for use in long-term optical monitoring of cell viability.

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The Coster-Kronig probability f23 for lead has been measured by a K-x-ray -L-x-ray coincidence technique. Analytic fitting of the Ea-x-ray triplet using nonlinear least-squares methodology was employed to determine the corrections necessitated by the overlap of the Ka2 and Ka& peaks. The result, 0. 112+0.002, is to be compared with the Dirac-Hartree-Slater prediction of 0.122 and a recently measured value of 0. 130+0.002 obtained by a different approach to the overlap correction.The present result may provide an estimate of relaxation and many-body effects, whichif includedwould lower the Dirac-Hartree-Slater single-particle-model prediction.

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