Scanning Electron Microscopy and X-ray Microanalysis

Providing a comprehensive introduction to the capabilities and use of scanning electron microscopes (SEM) and x-ray spectrometers, this highly acclaimed text emphasizes practical aspects of imaging and analysis for a broad audience of students and practitioners whose backgrounds span a wide range of science and technology. Topics discussed include user-controlled functions of scanning electron microscopes and x-ray spectrometers, the characteristics of electron beam - specimen interactions, image formation and interpretation, the use of x-rays for qualitative and quantitative analysis and the methodology for structural analysis using electron back-scatter diffraction. SEM sample preparation methods for hard materials, polymers, and biological specimens are covered in separate chapters. In addition, techniques for the elimination of charging in non-conducting specimens are detailed. A database of useful parameters for SEM and X-ray micro-analysis calculations and enhancements to the text chapters are available on an accompanying CD. This third edition has been extensively revised, including new sections on: Variable-pressure SEM, Electron backscatter diffraction (EBSD), Recent developments in x-ray detectors, and expanded coverage of: Low-voltage SEM, X-ray mapping, Specimen preparation. The text has been used in educating over 3,000 students at the Lehigh Microscopy School SEM short course as well as thousands of undergraduate and graduate students at universities worldwide

Donor-two-acceptor dye design:a distinct gateway to NIR fluorescence

\u3cp\u3eThe detection of chemical or biological analytes upon molecular reactions relies increasingly on fluorescence methods, and there is a demand for more sensitive, more specific, and more versatile fluorescent molecules. We have designed long wavelength fluorogenic probes with a turn-ON mechanism based on a donor-two-acceptor π-electron system that can undergo an internal charge transfer to form new fluorochromes with longer π-electron systems. Several latent donors and multiple acceptor molecules were incorporated into the probe modular structure to generate versatile dye compounds. This new library of dyes had fluorescence emission in the near-infrared (NIR) region. Computational studies reproduced the observed experimental trends well and suggest factors responsible for high fluorescence of the donor-two-acceptor active form and the low fluorescence observed from the latent form. Confocal images of HeLa cells indicate a lysosomal penetration pathway of a selected dye. The ability of these dyes to emit NIR fluorescence through a turn-ON activation mechanism makes them promising candidate probes for in vivo imaging applications.\u3c/p\u3

Scanning Electron Microscopy, X-Ray Microanalysis and Analytical Electron Microscopy

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