134 research outputs found
Laser Doppler Spectrum Analysis Based on Calculation of Cumulative Sums Detects Changes in Skin Capillary Blood Flow in Type 2 Diabetes Mellitus
No full textIn this article, we introduce a new method of signal processing and data analysis for the digital laser Doppler flowmetry. Our approach is based on the calculation of cumulative sums over the registered Doppler power spectra. The introduced new parameter represents an integral estimation for the redistribution of moving red blood cells over the range of speed. The prototype of the device implementing the technique is developed and tested in preliminary clinical trials. The methodology was verified with the involvement of two age groups of healthy volunteers and in a group of patients with type 2 diabetes mellitus. The main practical result of the study is the development of a set of binary linear classifiers that allow the method to identify typical patterns of the microcirculation for the healthy volunteers and diabetic patients based on the presented diagnostic algorithm
Investigation of Ba-Fe-O System near the BaFe<sub>12</sub>O<sub>19</sub>
No full textThis article presents an investigation on phase equilibria of barium hexaferrite and neighboring phases near its melting point and on the characteristics of the compounds in the vicinity of BaFe12O19 phase. Fe3O4, BaFe22+Fe163+O27 (W type), BaFe2+Fe143+O23 (X type), BaFe12O19 (M type), Ba2Fe22+Fe123+O22 (Y type), Ba3Fe22+Fe243+O41 (Z type) and BaFe2O4 (S type) were detected in the molten and solidified stoichiometric BaFe12O19. Literature data are summarized and compared with results of the present work.</jats:p
The mathematical modeling of the experiment on the determination of correlation coefficients in neutron beta-decay
No full textAnalysis of changes in blood flow oscillations under different probe pressure using laser Doppler spectrum decomposition
No full textPresently, in the modern laser Doppler flowmetry (LDF) the distribution of blood perfusion and its changes along the Doppler shift frequencies are simply ignored and/or not properly addressed. Utilizing the registered power spectrum of photocurrent, we introduce an LDF signal processing approach suitable for expanding of diagnostic capabilities of the technique. In particular, we demonstrate that it is possible to determine how the oscillations of blood flow (cardiac, breathe, myogenic, etc.) are distributed along the Doppler shift frequency. Wavelet analysis is utilized to extract the oscillations corresponded to the particular frequency sub-bands of blood perfusion. The main purpose of this study is to identify influence of local pressure by fiber optic probe on cardiac oscillations and their distribution along frequency of Doppler shift
Optical non-invasive diagnostics of microcirculatory-tissue systems of the human body: questions of metrological and instrumentation provision
No full textOptical techniques are one of the most promising non-invasive technologies for the diagnosis of medical conditions. This work is devoted to the current state of the optical non-invasive diagnostics (OND), especially about instrumentation as well as methodological and metrological provision for this technology. In some details Laser Doppler Flowmetry (LDF) and Fluorescence Spectroscopy (FS) diagnostics methods are considered. The main conclusion is that it is necessary to solve the problems of metrological support OND devices of these types. It is also important to develop a methodology based on diagnostic criteria obtained from a relationship between a number of OND methods and others
Hyperspectral system for Imaging of skin chromophores and blood oxygenation
No full textWe developed a compact, fast, hand-held hyperspectral imaging system for 2D neural network-based visualization of skin chromophores and blood oxygenation. Here, we present results of the system tests on healthy volunteers
Time-frequency analysis and laser Doppler spectrum decomposition to reveal new feature space for diagnosis of diabetes mellitus vascular complications
No full textAbstractEarly diagnostics of microcirculation complications is an important area for biomedical photonics application. The blood perfusion measurements are capable of identification of particular markers for diagnostics of many pathological conditions of blood microcirculation in the skin. In this work, we apply the laser Doppler flowmetry method with the ability to record and process the power spectra of registered photocurrent. This approach provides the estimation of signal amplitude distribution along with the frequencies of Doppler-broadened laser radiation and blood perfusion distribution. In this work, we investigate the blood ow in the skin by the time- frequency analysis of the recorded laser Doppler spectra. The conducted studies allowed us to propose new diagnostic criteria for the diagnosis of diabetes mellitus type 2 complications. The diagnostic parameters have been tested together with binary classifiers based on the linear discriminant analysis and demonstrated to be able to successfully distinguish the groups of volunteers of different age and patients with microvascular complications.Abstract
Early diagnostics of microcirculation complications is an important area for biomedical photonics application. The blood perfusion measurements are capable of identification of particular markers for diagnostics of many pathological conditions of blood microcirculation in the skin. In this work, we apply the laser Doppler flowmetry method with the ability to record and process the power spectra of registered photocurrent. This approach provides the estimation of signal amplitude distribution along with the frequencies of Doppler-broadened laser radiation and blood perfusion distribution. In this work, we investigate the blood ow in the skin by the time- frequency analysis of the recorded laser Doppler spectra. The conducted studies allowed us to propose new diagnostic criteria for the diagnosis of diabetes mellitus type 2 complications. The diagnostic parameters have been tested together with binary classifiers based on the linear discriminant analysis and demonstrated to be able to successfully distinguish the groups of volunteers of different age and patients with microvascular complications
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