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ABSTRACT Raman spectra of human hair cuticle measured in two experimental configurations with linearly polarized radiation focused on the lateral surface of the hair and on its cross section are compared. The bands at ~150, 220–230, 900, 935, 1321, 1338, and 1652 cm−1 are found to be polarization‐sensitive and assigned to the skeletal vibrations of α‐helices of hair keratins. However, different Raman spectra depending on the relative direction of signal collection can be obtained under identical polarization conditions for excitation. Several markers of the secondary structure of keratins (in particular, ~150, 935, and 1338 cm−1) may also be sensitive to the changes in the tertiary structure. [ABSTRACT FROM AUTHOR]

Abstract: Confocal Raman microspectroscopy is used to substantially supplement existing experimental data on historical blue‐green beads with respect to the presence and distribution of potassium antimony silicate (KSS) crystals. Problem of degradation of blue‐green beads on historical artifacts accounts for topicality of the work. The reasons for possible short‐term (several years) degradation of beads and the presence of neighboring damaged and undamaged beads on a single item remain unknown in spite of multiple experimental works on various glasses. Presence of KSS microcrystals may serve as a reason for degradation of beads. Raman measurements at several depths are used to determine the distribution and estimate sizes of KSS microcrystals. Such distributions are different for undamaged and strongly degraded beads. For degraded beads, Raman data show the depth dependence of the concentration of (non)bridged oxygens in the near‐surface layer with a thickness of 3–4 μm (i.e., inhomogeneity of glass matrix). The results prove the growth of KSS microcrystals in historical blue‐green beads, which may cause internal stress and, hence, degradation. The results can be used for optimization of storage conditions and restoration procedures for historical items. [ABSTRACT FROM AUTHOR]

It was shown experimentally that the effect of photobleaching in noninvasive measurement of the Raman spectra of light used in determining the carotenoid concentration in human skin can be used to increase measurement accuracy. Increased accuracy occurs as a consequence of a decrease in the measurable Raman spectra of the wideband fluorescent background intensity when a sample is irradiated by laser radiation. Furthermore, it was demonstrated that, for the spectra of skin from nine volunteers, the fluorescent background intensity can be decreased on average by a factor of 1.4, which leads to an increase in the signal-to-noise ratio for Raman lines of skin carotenoids by a factor of 1.2 on average. The kinetics of photobleaching of humans can be described by biexponential decay with a correlation coefficient close to unity, which agrees with the presented theoretical calculations. [ABSTRACT FROM AUTHOR]

A possibility for the low-frequency (terahertz) vibrational motions of large parts of protein molecules is considered and the characteristic frequencies are estimated. The problem of damping of these motions is discussed and the effect of solvent molecules on the model low-frequency molecular oscillators is experimentally studied using Raman spectroscopy. The data obtained show that the effect of solvent is not reduced to a decrease in the Q factor and causes variations in frequencies and relative amplitudes of the low-frequency oscillations. [ABSTRACT FROM AUTHOR]

Presents a study which examined the structure of ricin, ricin agglutinin, and ricin B-subunit in water solution. Use of Raman spectrocopy in the study; Function of A- and B-subunits of ricin and ricin agglutinin; Degree of homology between amino acid sequences of both ricin and ricin agglutinin; Description of the optical scheme of the Raman spectrometer used in the experiment.

In the Acknowledgments on page 655 the second Project number should read No. 17-02-01411-а. [ABSTRACT FROM AUTHOR]