In view of its potential for biological tissues analyses at a molecular level, Raman spectroscopy in optical range has been the object of biomedical research for the last years. The main aim of this work is the development of Raman spectroscopy for organic content identifying and determination of biomarkers of saliva at a molecular level for periodontitis diagnostics. Four spectral regions were determined: 1155 and 1525 cm −1 , 1033 and 1611 cm −1 , which can be used as biomarkers of this widespread disease.An informative volume deposition on the dried saliva drop (50× magnifications)

This article presents a new simple method of creating light-absorbing carbon material for optical devices such as bolometers. A simple method of laser microstructuring of graphene oxide is used in order to create such material. The absorption values of more than 98% in the visible and more than 90% in the infrared range are achieved. Moreover thermal properties of the films, such as temperature dependence and the thermal response of the samples, are studied. The change in resistance with temperature is 13 Ohm K, temperature coefficient of resistance (TCR) is 0.3% K, and the sensitivity is 0.17 V W at 300 K. Thermal conductivity is rather high at ∼104 W m K at 300 K. The designed bolometer operates at room temperature using incandescent lamp as a light source. This technique suggests a new inexpensive way to create a selective absorption coating and/or active layer for optical devices. Developed GO and rGO films have a large surface area and high conductivity. These properties make carbon coatings a perfect candidate for creating a new type of optoelectronic devices (gas sensors, detectors of biological objects, etc.).

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Core/shell Si/SiO x nanoparticles (Si/SiO x -NP) having bright red-infrared photoluminescence were obtained by a three-stage synthesis based on the thermal disproportionation of microdispersed SiO. Transformation patterns of structure and spectroscopic properties of the material during passage through all process stages (starting from initial SiO microparticles and up to the Si/SiO x -NP sols) have been revealed by using Raman, photoluminescence and ESR spectroscopy, XPS, XRD, and electron microscopy. Thermal annealing of SiO microparticles (stage I) results in formation of amorphous-crystalline Si nanophase in the matrix of SiO 2 , as well as generation of paramagnetic P b centres with the concentration up to 4 9 10 18 particles/g. At the annealing temperature, T an [ 900°C, a rapid growth of nanocrystal sizes takes place, and, simultaneously, a rapid growth of paramagnetic P b centre concentration occurs. Elimination of SiO 2 from the annealed sample by etching in HF (stage II) stimulates further crystallization of amorphous-crystalline core, caused by stress relaxation inside the Si core when removing SiO 2 matrix. Functionalization of nanoparticle surface (stage III) allows obtaining core/shell Si/SiO x -NP with a bright red-infrared photoluminescence and their sols. Average size of the crystalline Si core increases from 4.7 to 11.1 nm when T an at the stage I rises from 350 to 1100°C. At relatively low T an = 350°C, the nanoparticles with monocrystalline Si cores are mainly formed, while at T an [ 1100°C, a large number of polycrystalline Si nanoparticles are also observed. Our TEM images have revealed the existence of monocrystalline Si nanoparticles having significantly different contrast even at comparable nanoparticle sizes. We attribute that to the formation of both bulk (with a high TEM contrast) and flat (2D) Si nanocrystals (with a low TEM contrast) in the course of SiO annealing.

In this work, the spatial localization of leucocytes, bacteria, and erythrocytes in the crystal pattern of a dried droplet of cerebrospinal fluid (CSF) is established. Characteristic lines are detected and identified in the Raman spectrum of the CSF that point to the presence of pathologic cells therein and can be used in a timely way to diagnose meningitis, the spectroscopic sample preparation procedure being simple enough. A dry CSF sample retains its characteristic spectral features for no less than three days, which is important for its safe keeping and transportation, and also for the computer processing of its spectra.