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91 results on '"Vrazhnov, Denis A."'

3. Photoacoustic Imaging of Brain

Author

Sunder, Mridula, Mazumder, Nirmal, Kistenev, Yury V., Vrazhnov, Denis A., Mazumder, Nirmal, editor, Gangadharan, Gireesh, editor, and Kistenev, Yury V., editor

Published
2022
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5. Indirect Imaging

Author

Peng, Yan, Shi, Chenjun, Kistenev, Yury V., Vrazhnov, Denis A., Cherkasova, Olga P., Mazumder, Nirmal, editor, Gangadharan, Gireesh, editor, and Kistenev, Yury V., editor

Published
2022
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9. Front Matter

Author

Kistenev, Yury V., primary, Borisov, Alexey V., primary, and Vrazhnov, Denis A., primary

Published
2021
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11. Back Matter

Author

Kistenev, Yury V., primary, Borisov, Alexey V., primary, and Vrazhnov, Denis A., primary

Published
2021
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25. Terahertz Time-Domain Spectroscopy of Glioma Patient Blood Plasma: Diagnosis and Treatment.

Author

Cherkasova, Olga, Vrazhnov, Denis, Knyazkova, Anastasia, Konnikova, Maria, Stupak, Evgeny, Glotov, Vadim, Stupak, Vyacheslav, Nikolaev, Nazar, Paulish, Andrey, Peng, Yan, Kistenev, Yury, and Shkurinov, Alexander

Subjects
TERAHERTZ time-domain spectroscopy, BLOOD plasma, CENTRAL nervous system tumors, GLIOMAS, MACHINE learning, SUPPORT vector machines
Abstract

Gliomas, one of the most severe malignant tumors of the central nervous system, have a high mortality rate and an increased risk of recurrence. Therefore, early glioma diagnosis and the control of treatment have great significance. The blood plasma samples of glioma patients, patients with skull craniectomy defects, and healthy donors were studied using terahertz time-domain spectroscopy (THz-TDS). An analysis of experimental THz data was performed by machine learning (ML). The ML pipeline included (i) THz spectra smoothing using the Savitzky–Golay filter, (ii) dimension reduction with principal component analysis and t-distribution stochastic neighborhood embedding methods; (iii) data separability analyzed using Support Vector Machine (SVM), Random Forest (RF), and Extreme Gradient Boosting (XGBoost). The ML models' performance was evaluated by a k-fold cross validation technique using ROC-AUC, sensitivity, and specificity metrics. It was shown that tree-based ensemble methods work more accurately than SVM. RF and XGBoost provided a better differentiation of the group of patients with glioma from healthy donors and patients with skull craniectomy defects. THz-TDS combined with ML was shown to make it possible to separate the blood plasma of patients before and after tumor removal surgery (AUC = 0.92). Thus, the applicability of THz-TDS and ML for the diagnosis of glioma and treatment monitoring has been shown. [ABSTRACT FROM AUTHOR]

Published
2023
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26. Application of machine learning algorithms and laser absorption spectroscopy to solve the problem of determining components with a low concentration in multicomponent gas mixtures

Author

Prischepa, V. V., Skiba, V. E., Borisov, Alexey V., and Vrazhnov, Denis A.

Subjects
спектры поглощения, кодировщики, нейронные сети, компонентный анализ, метод алгебраической реконструкции, машинное обучение
Abstract

This article describes the methods and approaches used by us to solve the problem of a high error in the determination of a component with a low concentration in a gas mixture. The approaches based on the modification of the machine learning model were considered, the approach to the generation of the training sample was changed, an iterative method for increasing the accuracy of the model results was proposed.

Published
2021

27. Efficiency of the phasor plot approach for the analysis of the antimicrobial properties of nanoparticles using two-photon microscopy

Author

Nikolaev, Viktor V., Vrazhnov, Denis A., and Lozhkomoev, A. S.

Subjects
автофлуоресценция, метициллин-резистентный золотистый стафилококк, двухфотонная микроскопия, FLIM-микроскопия
Abstract

Two-photon microscopy methods have been actively developing in the last two decades. In particular, various approaches are being developed to analyze metabolic activity obtained by laser microscopy with high temporal resolution. One such approach is ploting the autofluorescence lifetime signal data to the phasor plot and observe deviations from the normal state. This tool has proven itself well for analyzing the metabolic activity of biological objects, including bacteria. This study analyzes the antimicrobial activity for MRSA bacteria by phasor plot approach. It was possible to show that, the lifetime of autofluorescence in the phasor plane changes depending on the type of nanoparticles used, with which bacteria are incubated. This result can be used in the future for rapid assessment of the antimicrobial activity of nanoparticles. The research was carried out with the support of a grant under the Decree of the Government of the Russian Federation No. 220 of 09 April 2010 (Agreement No. 075-15-2021-615 of 04 June 2021) and was performed according to the Government research assignment for ISPMS SB RAS, project FWRW-2019-0033

Published
2021

29. Informative feature selection method for Raman micro-spectroscopy data

Author

Karmenyan, Artashes V., primary, Vrazhnov, Denis A., additional, Sandykova, Ekaterina A., additional, Perevedentseva, Elena V., additional, Krivokharchenko, Alexander, additional, Nadtochenko, Victor A., additional, Cheng, Chia-Liang, additional, Kabanova, Tatyana V., additional, and Malakhova, Tatyana E., additional

Published
2021
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31. Terahertz spectroscopy of diabetic and non-diabetic human blood plasma pellets

Author

Lykina, Anastasiya A., primary, Nazarov, Maksim M., additional, Konnikova, Maria R., additional, Mustafin, Ilia A., additional, Vaks, Vladimir L., additional, Anfertev, Vladimir A., additional, Domracheva, Elena G., additional, Chernyaeva, Mariya B., additional, Kistenev, Yuri V., additional, Vrazhnov, Denis A., additional, Prischepa, Vladimir V., additional, Kononova, Yulia A., additional, Korolev, Dmitry V., additional, Cherkasova, Olga P., additional, Shkurinov, Alexander P., additional, Babenko, Alina Y., additional, and Smolyanskaya, Olga A., additional

Published
2021
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33. Diagnosis of Glioma Molecular Markers by Terahertz Technologies

Author

Cherkasova, Olga, primary, Peng, Yan, additional, Konnikova, Maria, additional, Kistenev, Yuri, additional, Shi, Chenjun, additional, Vrazhnov, Denis, additional, Shevelev, Oleg, additional, Zavjalov, Evgeny, additional, Kuznetsov, Sergei, additional, and Shkurinov, Alexander, additional

Published
2021
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34. Imitation of optical coherence tomography images by wave Monte Carlo-based approach implemented with the Leontovich–Fock equation

Author

Bulygin, Andrey D., Vrazhnov, Denis A., Sim, Elena S., Meglinski, Igor, and Kistenev, Yury V.

Subjects
Physics::Medical Physics
Abstract

We present a computational modeling approach for imitation of the time-domain optical coherence tomography (OCT) images of biotissues. The developed modeling technique is based on the implementation of the Leontovich–Fock equation into the wave Monte Carlo (MC) method. We discuss the benefits of the developed computational model in comparison to the conventional MC method based on the modeling of OCT images of a nevus. The developed model takes into account diffraction on bulk-absorbing microstructures and allows consideration of the influence of the amplitude–phase profile of the wave beam on the quality of the OCT images. The selection of optical parameters of modeling medium, used for simulation of optical radiation propagation in biotissues, is based on the results obtained experimentally by OCT. The developed computational model can be used for imitation of the light waves propagation both in time-domain and spectral-domain OCT approaches.

Published
2020

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