A modular system of techniques and software has been developed for the calibration and correction of intensity linearity, uniformity of response, spatial distortion, and image plate decay. With calibration the Molecular Dynamics TM Imaging Plate scanner system has been shown to give comparable results to the MarResearchTM scanner. The ESRF x-ray image intensifier/charge-coupled device detectors inherently cause large spatial and uniformity of response distortions, and successful data analysis depends on calibration and correction. Results of synchrotron radiation experiments are presented.

Charge-coupled device (CCD)-based X-ray detectors allow data to be collected much more quickly (--,10 times) than with current on-line imaging-plate systems. At the ESRF, X-ray image intensifier/CCD detector systems have been developed. These have great potential as fast read-out detectors for macromolecular and other forms of crystallography. They are relatively large sensitive X-ray detectors but have two inherent weaknesses: convex detection surfaces leading to spatial distortion and non-uniformity of intensity response, and susceptibility to small changes in magnetic fields. A large improvement has been made to the accuracy obtained by non-uniformity of response calibration and correction, using fluorescence from doped lithium borate glasses. Monochromatic macromolecular crystallography demonstration experiments with external user groups have shown that high-quality results may be obtained under real experimental conditions.

Single-cell characterisation and rapid enumeration of E. coli was achieved by confining them into the picoliter droplets of a water-in-oil fuorinated emulsion. Micro-confinement of Bacteria into w/o Emulsion Droplets for Rapid Detection and Enumeration AbstractToday, rapid detection and identification of bacteria in microbiological diagnosis is a major issue. Reference methods usually rely on growth of micro-organisms, with the drawback of lengthy time-to-result. The method provides global information on a clonal population that is known to be inhomogeneous relative to metabolic states and activities. Therefore, there may be a significant advantage of methods that allow characterization of individual bacteria from a large population, both for test time reduction and the clinical value of the characterization. We report here a method for rapid detection and real-time monitoring of the metabolic activities of single bacteria. Water-in-oil emulsions were used to encapsulate single Escherichia coli cells into picolitre (pL)-sized microreactor droplets. The glucuronidase activity in each droplet was monitored using the fluorogenic reporter molecule MUG (4-Methylumbelliferyl β-D-glucuronide) coupled to time-lapse fluorescence imaging of the droplets. Such bacterial confinement provides several major advantages. 2 1) Enzymatic activities of a large number of single bacterium-containing droplet could be monitored simultaneously, allowing the full characterization of metabolic heterogeneity in a clonal population. We monitored glucuronidase enzymatic activity and growth over ~200 single bacteria over a 24h-period. 2) Micro-confinement of cells in small volumes allows rapid accumulation of the fluorescent metabolite, hence decreasing the detection time. Independent of the initial concentration of bacteria in the sample, detection of the presence of bacteria could be achieved in less than two hours. 3) Considering the random distribution of bacteria in droplets, this method allowed rapid and reliable enumeration of bacteria in the initial sample. Overall, the results of this study showed that confinement of bacterial cells increased the effective concentration of fluorescent metabolites leading to rapid (2 h) detection of the fluorescent metabolites, thus significantly reducing time to numeration.