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Raman spectroscopy is a potentially important clinical tool for real-time diagnosis of disease and in situ evaluation of living tissue. The purpose of this article is to review the biological and physical basis of Raman spectroscopy of tissue, to assess the current status of the field and to explore future directions. The principles of Raman spectroscopy(More)
We have developed a novel optical method for observing submicrometer intracellular structures in living cells, which is called confocal light absorption and scattering spectroscopic (CLASS) microscopy. It combines confocal microscopy, a well-established high-resolution microscopic technique, with light-scattering spectroscopy. CLASS microscopy requires no(More)
Esophageal cancer is increasing in frequency in the United States faster than any other cancer. Barrett's esophagus, an otherwise benign complication of esophageal reflux, affects approximately three million Americans and precedes almost all cases of esophageal cancer. If detected as high-grade dysplasia (HGD), most esophageal cancers can be prevented.(More)
This article reports the development of an optical imaging technique, confocal light absorption and scattering spectroscopic (CLASS) microscopy, capable of noninvasively determining the dimensions and other physical properties of single subcellular organelles. CLASS microscopy combines the principles of light-scattering spectroscopy (LSS) with confocal(More)
The outcomes of the clinical trials of the γ-secretase inhibitor Semagacestat (LY-450139) and the γ-secretase modulator (GSM) Tarenflurbil were disappointing, but may not represent the end of the γ-secretase era. γ-Secretase modulators, by definition, only block the γ-secretase cleavage of amyloid-β protein precursor (AβPP) to generate the longer,(More)
The Zalpha domain of human double-stranded RNA adenosine deaminase 1 binds specifically to left-handed Z-DNA and stabilizes the Z-conformation. Here we report spectroscopic and analytical results that demonstrate that Zalpha can also stabilize the left-handed Z-conformation in double-stranded RNA. Zalpha induces a slow transition from the right-handed(More)
We describe a new scanning microscopy technique, phase-dispersion microscopy (PDM). The technique is based on measuring the phase difference between the fundamental and the second-harmonic light in a novel interferometer. PDM is highly sensitive to subtle refractive-index differences that are due to dispersion (differential optical path sensitivity, 5 nm).(More)
The molecular bases of Alzheimer disease and related neurodegenerative disorders are becoming better understood, but the means for definitive diagnosis and monitoring in vivo remain lacking. Near-infrared optical spectroscopy offers a potential solution. We acquired transmission and reflectance spectra of thin brain tissue slabs, from which we calculated(More)
From astronomy to cell biology, the manner in which light propagates in turbid media has been of central importance for many decades. However, light propagation near the point-of-entry in turbid media has never been analytically described, until now. Here we report a straightforward and accurate method that overcomes this longstanding, unsolved problem in(More)