There is currently a significant interest in understanding how cells and tissues respond to mechanical stimuli, but current approaches are limited in their capability for measuring responses in real time in live cells or viable tissue. A protocol was developed with the use of a cell actuator to distend live cells grown on or tissues attached to an elastic substrate while imaging with confocal and atomic force microscopy (AFM). Preliminary studies show that tonic stretching of human bronchial epithelial cells caused a significant increase in the production of mitochondrial superoxide. Moreover, using this protocol, alveolar epithelial cells were stretched and imaged, which showed direct damage to the epithelial cells by overdistention simulating one form of lung injury in vitro. A protocol to conduct AFM nano-indentation on stretched cells is also provided. Video LinkThe video component of this article can be found at

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The performance of grazing incidence x-ray optical systems is severely compromised by arc-second slope errors arising from surface irregularities in the millimeter spatial period range. It is those errors that limit the performance of most of the aspheric optical systems in use at the National Synchrotron Light Source (NSLS) and it is those errors that are most difficult to control during the polishing process. We present here a set of scanning pinhole measurements made on a grazing incidence cylinder mirror which exhibit typical arc-second beam deflections and then correlate these measurements with surface roughness measurements made with a WYKO optical surface profiler. The average power spectral density (PSD) curve for the surface is computed from the profile measurements, and the various bandwidth-dependent statistical quantities, such as RMS roughness and slope error, which are computed from the PSD curve, are compared with the results from the scanning pinhole measurements.

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