Two-dimensional codistribution spectroscopy applied to UVRR and ROA investigations of biomolecular transitions

Automatic Determination of the Sequential Order of Dynamic Data and Its Application to Vibrational Spectroscopy

For over the past 30 years, generalized two-dimensional correlation spectroscopy has formed an active and widespread research area. One of the most attractive properties of this method is that one can determine the sequential order of signal changes. But the determination of the sequential order has only been done manually for several arbitrarily chosen bands. In this paper, we develop a method to automatically determine the sequential order of all of the band intensity changes, and we applied this method to band changes of vibration spectra. This method will open a door to analyze more complicated signals often seen in life phenomena.

Vibrational two-dimensional correlation spectroscopy (2DCOS) study of proteins

A tutorial is provided for the generalized two-dimensional correlation spectroscopy (2DCOS), which is applicable to the vibrational spectroscopic study of proteins and related systems. In 2DCOS, similarity or dissimilarity among variations of spectroscopic intensities, which are induced by applying an external perturbation to the sample, is examined by constructing correlation spectra defined by two independent spectral variable axes. By spreading congested or overlapped peaks along the second dimension, apparent spectral resolution is enhanced and interpretation of complex spectra becomes simplified. A set of simple rules for the intensities and signs of correlation peaks is used to extract insightful information. Simulated IR spectra for a model protein are used to demonstrate the specific utility of 2DCOS. Additional tools useful in the 2DCOS analysis of proteins, such as data segmentation assisted with moving-window analysis, 2D codistribution analysis, Pareto scaling, and null-space projection are also discussed.