Raman Microspectroscopy of Hair: Low-Frequency Markers of Protein Secondary Structure.

Low-frequency intervals that can be used to study the secondary structure of proteins are determined. Compared are Raman spectra of keratins from unpigmented human hair, measured in two experimental configurations: with excitation radiation coaxial with the hair and perpendicular to it. Based on the polarization sensitivity, the bands peaked at 150 and 221 cm are assigned to vibrations of α-helical structures.

Raman spectroscopy of thermo- and laser-induced transformations of gouache paint layer of copper phthalocyanine blue.

Methods to control polymorphic modifications of phthalocyanines using optical (laser) radiation and possible photoinduced transformations of polymorphs are of practical interest in problems of identification and attribution of paintings, laser (micro)sampling, and the development of phthalocyanine structures for technical applications in optics, optoelectronics, and medicine. In this work, we compare the thermal and laser-induced changes of a gouache paint layer based on copper phthalocyanine (CuPc) PB15. The thermally induced color changes of the paint layer are quantified using the CIE Lab D65/10 color space.

Effect of multiplicative noise on stationary stochastic process.

An open system that can be analyzed using the Langevin equation with multiplicative noise is considered. The stationary state of the system results from a balance of deterministic damping and random pumping simulated as noise with controlled periodicity. The dependence of statistical moments of the variable that characterizes the system on parameters of the problem is studied.

Low-frequency vibrational spectroscopy of proteins with different secondary structures.

Fourier transform infrared (FTIR) and Raman spectra of proteins with significantly different structures are measured in a spectral interval of 50 to 500 ?? cm ? 1 and noticeable spectral differences are revealed. Intensities of several spectral bands correlate with contents of secondary structure elements. FTIR spectra of superhelical proteins exhibit developed spectral features that are absent in the spectra of globular proteins.

Photoinduced formation of thiols in human hair.

Raman, scanning electron, and optical microscopy of hair and spectrophotometry of soluble hair proteins are used to study the effect of UV-vis radiation on white hair. The samples of a healthy subject are irradiated using a mercury lamp and compared with non-irradiated (control) hair. The cuticle damage with partial exfoliation is revealed with the aid of SEM and optical microscopy of semifine sections.

Fourier Transform Infrared (FT-IR) Microspectroscopy of 20th Century Russian Oil Paintings: Problem of Dating.

Analysis of the IR spectra of samples from 230 Russian oil paintings of the 20th century is used to propose a procedure for the threshold estimation of the age of paintings based on measured parameters (intensity ratios of spectral bands). The bands of compounds that are formed upon interaction of pigment (zinc white) with oil are used for dating.

Raman microspectroscopy of nanodiamond-induced structural changes in albumin.

Nanodiamonds (NDs) are promising agents for theranostic applications due to reported low toxicity and high biocompatibility, which is still being extensively tested on cellular, tissue, and organism levels. It is presumed that for experimental and future clinical applications, NDs will be administered into the organism via the blood circulation system. In this regard, the interaction of NDs with blood components needs to be thoroughly studied.

Effect of thermal denaturation, inhibition, and cleavage of disulfide bonds on the low-frequency Raman and FTIR spectra of chymotrypsin and albumin.

The analysis of the structure-function relationship is extremely important in the study of proteins. The importance of function-related motions of large parts or subglobules of protein molecules stimulates the spectroscopic study in the low-frequency (terahertz) domain. However, only tentative assignments are available and the spectroscopic data are insufficiently discussed in terms of structural changes.

Raman microspectroscopy of old paper samples with foxing.

Diagnostic methods and historical document and artwork (in particular, paper items) analysis using modern physical methods is a topical practical problem. Paper materials exhibit nonuniform degradation with the formation of foxing stains. Correct physicochemical identification of the structure of foxed fragments depends on the efficiency of the experimental technique and offers guidelines for restoration.

Optimization of the rolling-circle filter for Raman background subtraction.

A procedure is proposed to optimize a high-pass filter enabling one to subtract the broadband background signals inherent in Raman spectra. A spectral approach is used to analyze the characteristics of the filter and the distortions in the processed spectra. Examples of the processing of real spectra are presented.

Polarization sensitive coherent anti-Stokes Raman scattering spectroscopy of the amide I band of proteins in solutions.

Polarization sensitive coherent anti-Stokes Raman scattering (PCARS) spectroscopy is a fruitful technique to study Raman vibrations of diluted molecules under off-electron resonant conditions. We apply PCARS as a direct spectroscopic method to investigate the broad amide I band of proteins in heavy water. In spontaneous Raman spectroscopy, this band is not well resolved.