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Synchrotron light powers IR microscope A synchrotron accelerates electrons to produce high-intensity radiation with energies ranging from the visible through the UV to the soft and hard X-ray regions of the spectrum, produc ing a beam of coherent light 1000 times brighter than conventional labo ratory light sources. Analytical tech niques that benefit from synchro tron light sources include X-ray diffrac tion, electron energy loss, and X-ray photoemission spectrometries. The high spectral brightness of synchro tron light provides a good signal-tonoise ratio even for minute samples. For the first time, a scanning IR microscope has been connected to a synchrotron light source. The micro scope, manufactured by Spectra-Tech, was installed at Brookhaven National Laboratory's (BNL) National Synchro tron Light Source (NSLS) in collabora tion with Grumman Corp. and the Car negie Institution's Geophysical Lab oratory. Synchrotron light will enhance the microscope's performance by about 100-fold. According to John
ANALYTICAL CHEMISTRY Sixty-five years of analytical history Analytical Chemistry is pleased to an nounce the publication of Milestones in Analytical Chemistry, a compendium of 60 350 A
searchers from the Carnegie Institu tion's Geophysical Laboratory investi gated the chemical composition of rocks and inclusions inside diamonds, silicates, and some volatile materials to gain a better understanding of the Earth's interior and of geologic phe nomena such as earthquakes and vol canoes. Researchers at the University of Chicago have measured the absorp tion spectra of 10-μπι interplanetary dust particles (micrometeorites). A comparison of these results with IR emission spectra of protostellar objects Researchers examine IR microspectroscopy (solar systems in the early stages of data. (Front to back: Mary Tungol, FBI; formation), allowed researchers to in Larry Can, Grumman Corp.; Gwyn fer which minerals may be present in Williams, BNL; John Reffner, Spectrathe objects. Tech) Spectra-Tech, in collaboration with Polaroid, used the instrument to obtain chemical profiles of a cross section of Refiner of Spectra-Tech, it is possible film coated with five layers of poly to analyze a sample as thin as 5 μηι in mers. Results from this work should seconds with the same precision possi lead to better photographic films. Fo ble on samples 50 times larger. Using rensic researchers at the FBI deter the NSLS, researchers have achieved mined the chemical composition of full theoretical resolution of the micro explosives particles and thin layers of scope, with no optical distortion. paint and have examined strands of The microscope has both terrestrial hair for drug residues. and interplanetary applications. Re
influential research papers published since 1929. Authors represented in the book include Fassell, Beckman, Schoolery, Savitzky and Golay, Horlick, Nichol son and Shain, Merrifield, and Kolthoff. The book is organized by decade; each decade is prefaced with an introduction, written by the Washington editorial staff, highlighting scientific, cultural, and his toric events. Each technical paper is intro duced with a brief commentary, written by an expert in the field, citing the signifi cance of the work. Cost is $74.95; dis counts are available for multiple-copy purchases. To order, contact ACS Distri bution Dept, 1155 16th St., N.W., Wash ington, DC 20036 (800-227-5558 in the U.S. and Canada; 202-872-4363 in Wash ington, DC, and outside the U.S.; fax 202872-6067).
Analytical Chemistry, Vol. 66, No. 6, March 15, 1994
Calcium imaging to see learning as it occurs A professor lecturing at the front of a classroom often wonders how much of what is being said is getting through to the students. By using calcium imaging to monitor the activity of cortical neurons, researchers hope to actually visualize learning as it occurs. The synapse is the smallest, most local site for nerve communication, learning, and memory. Researchers Timothy H. Murphy and Jay M. Baraban of Johns Hopkins University School of Medicine and W. Gil Wier and Lothar A. Blatter of the University of Maryland School of Medicine used miniature excitatory syn aptic currents (MESCs), a form of com munication between neurons, to induce Ca2+ transients to monitor activity at indi-
