Necessity and Use of a Multilayer Test Object Based on an Anonymous 19th Century Copy of a Painting by Ivan Konstantinovich Aivazovsky (1817–1900)

The emergence of new research methods in the field of heritage science always raises a large number of questions related to their applicability, reproducibility of results on similar objects, complementarity with other methods, and development of new research methods. To solve such problems, it is necessary to have a test object with the required structure. A multilayer test object based on a fragment of a copy of a 19th century painting by I.K. Aivazovsky was created and described. Analytical studies of the colourful layers were carried out on a Fourier-transform infrared (FT-IR) spectrometer with an attenuated total reflectance (ATR) attachment in single-reflection mode with a diamond crystal. As part of the use of one research method, differences between painting layers of the 19th and 20th centuries were revealed. Results are presented in the IR graphs. The aim of the work was to identify the characteristics of the pictorial layers inherent in the copy of the painting by I.K. Aivazovsky. This will improve the methodology of technological expertise of the I.K. Aivazovsky’s artworks

Necessity and Use of a Multilayer Test Object Based on an Anonymous 19th Century Copy of a Painting by Ivan Konstantinovich Aivazovsky (1817–1900)

The emergence of new research methods in the field of heritage science always raises a large number of questions related to their applicability, reproducibility of results on similar objects, complementarity with other methods, and development of new research methods. To solve such problems, it is necessary to have a test object with the required structure. A multilayer test object based on a fragment of a copy of a 19th century painting by I.K. Aivazovsky was created and described. Analytical studies of the colourful layers were carried out on a Fourier-transform infrared (FT-IR) spectrometer with an attenuated total reflectance (ATR) attachment in single-reflection mode with a diamond crystal. As part of the use of one research method, differences between painting layers of the 19th and 20th centuries were revealed. Results are presented in the IR graphs. The aim of the work was to identify the characteristics of the pictorial layers inherent in the copy of the painting by I.K. Aivazovsky. This will improve the methodology of technological expertise of the I.K. Aivazovsky’s artworks

Agar and Silica Gel Based Biotissue-mimicking Phantoms in THz Frequency Range

International audienc

A comparison of terahertz optical constants and diffusion coefficients of tissue immersion optical clearing agents

We performed the transmission-mode terahertz (THz) pulsed spectroscopy of several THz-wave penetration- enhancing agents (PEAs): glycerol, propylene glycol, ethylene glycol, and polyethylene glycol, featuring the molecular weight of 200, 300 and 400. We vacuumized the THz beam path in order to reduce an impact of water vapor on measured data. We reconstructed optical properties and dielectric constants of the abovementioned PEAs in the spectral range of 0.1 to 2.5 THz. We analyzed measured THz optical properties along with the literature data for coefficients of PEAs' diffusion into tissues in order to objectively uncover strength and weaknesses of their use in the immersion optical clearing of tissues at THz frequencies

Study of blood plasma optical properties in mice grafted with Ehrlich carcinoma in the frequencyrange 0.1–1.0 THz

International audienceIn the course of in vitro studies of blood of laboratory animals with progressing Ehrlich carcinoma, we have revealed the change of the blood plasma optical properties in the THz range, which can be used for developing the express diagnostics of the presence of oncological diseases. An applied software package is elaborated that allows the phantoms of biological samples having a complex structure to be numerically simulated and the parameters of the electromagnetic wave reflected from these samples in the THz frequency range to be calculated

In Situ Study of the Painting “Hiroshima I” (1958) by Werner Tübke (1929–2004)

This article presents the results of technical studies of the oil painting by the artist of German origin Werner Tübke “Hiroshima I” (1958). The creative heritage of this author has not been studied enough and represents scattered data on the technology of painting and artistic techniques. The aim of this work was to determine the art materials and painting technology described in his diaries, using the example of his only painting represented in Russia: “Hiroshima I”. For this purpose, an in situ approach was implemented using some simple museum instrumentations—UV-induced visible luminescence, infrared reflectography (IRR), radiography, portable X-ray fluorescence (XRF), Fourier transform Infrared spectroscopy (FT-IR), and polarizing microscopy using microprobes. As a result, the pigment composition of the painting layers could be determined, the painting technology refined, and a previously unknown hidden portrait of Werner Tübke’s father revealed

Terahertz spectroscopy of diabetic and non-diabetic human blood plasma pellets

Significance: The creation of fundamentally new approaches to storing various biomaterial and estimation parameters, without irreversible loss of any biomaterial, is a pressing challenge in clinical practice. We present a technology for studying samples of diabetic and non-diabetic human blood plasma in the terahertz (THz) frequency range. Aim: The main idea of our study is to propose a method for diagnosis and storing the samples of diabetic and non-diabetic human blood plasma and to study these samples in the THz frequency range. Approach: Venous blood from patients with type 2 diabetes mellitus and conditionally healthy participants was collected. To limit the impact of water in the THz spectra, lyophilization of liquid samples and their pressing into a pellet were performed. These pellets were analyzed using THz time-domain spectroscopy. The differentiation between the THz spectral data was conducted using multivariate statistics to classify non-diabetic and diabetic groups’ spectra. Results:We present the density-normalized absorption and refractive index for diabetic and nondiabetic pellets in the range 0.2 to 1.4 THz. Over the entire THz frequency range, the normalized index of refraction of diabetes pellets exceeds this indicator of non-diabetic pellet on average by 9% to 12%. The non-diabetic and diabetic groups of the THz spectra are spatially separated in the principal component space. Conclusion: We illustrate the potential ability in clinical medicine to construct a predictive rule by supervised learning algorithms after collecting enough experimental data

Multimodal optical diagnostics of glycated biological tissues

Diabetes mellitus is a metabolic disorder characterized by chronic hyperglycemia accompanied by the disruption of carbohydrate, lipid, and proteins metabolism and development of longterm microvascular, macrovascular, and neuro pathic changes. This review presents the results of spectroscopic studies on the glycation of tissues and cell proteins in organ isms with naturally developing and model diabetes and in vitro glycated samples in a wide range of electromagnetic waves, from visible light to terahertz radiation. Experiments on the refractometric measurements of glycated and oxygenated hemoglobin in broad wavelength and temperature ranges using digital holographic microscopy and diffraction tomography are discussed, as well as possible application of these methods in the diabetes diagnostics. It is shown that the development and implementation of multimodal approaches based on a combination of phase diagnostics with other methods is another promising direction in the diabetes diagnostics. The possibilities of using optical clearing agents for monitoring the diffusion of substances in the glycated tissues and blood flow dynamics in the pancreas of animals with induced diabetes have also been analyzed

Terahertz biophotonics as a tool for studies of dielectric and spectral properties of biological tissues and liquids

In this review, we describe dielectric properties of biological tissues and liquids in the context of terahertz (THz) biophotonics. We discuss a model of the THz dielectric permittivity of water and water-containing media, which yields analysis of the relaxation and damped resonant molecules modes. We briefly describe modern techniques of THz spectroscopy and imaging employed in biophotonics with a strong emphasize on a THz time-domain spectroscopy. Furthermore, we consider the methods of sub-wavelength resolution THz imaging and the problem of THz wave delivery to hard to access tissues and internal organs. We consider the THz dielectric properties of biological solutions and liquids. Although strong absorption by water molecules prevents THz-waves from penetration of hydrated tissues and probing biological molecules in aqueous solutions, we discuss approaches for overcoming these drawbacks – novel techniques of freezing and temporal dehydration by application of hyperosmotic agents which have a potential for cancer detection. We review recent applications of THz technology in diagnosis of malignancies and aiding histology paying particular attention to the origin of contrast observed between healthy and pathological tissues. We consider recent applications of THz reflectometry in sensing the thinning dynamics of human pre-corneal tear film. Modern modalities of THz imaging, which relies on the concepts of multi-spectral and multi-temporal domains and employing the principles of color vision, phase analysis and tomography are discussed. Novel methods of THz spectra analysis based on machine learning, pattern recognition, chemical imaging and the revealing of the spatial distribution of various substances in a tissue, are analyzed. Advanced thermal model describing biological object irradiated by THz waves and phantoms mimicking the optical properties of tissues at THz frequencies are presented. Finally, application of the high-resolution THz spectroscopy in analytic chemistry, biology and medicine are described