Sirvi Autor "Makarov, Aleksandr" järgi

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Mastering the Unseen: Approaches to Hard-to-Detect Viral Cytopathic Effect
(Tartu Ülikool, 2025) Makarov, Aleksandr; Fishman, Dmytro, juhendaja; Tartu Ülikool. Loodus- ja täppisteaduste valdkond; Tartu Ülikool. Arvutiteaduse instituut
Viral infections pose persistent global health challenges, making rapid, accurate assessment of viral activity crucial for research and diagnostics. Cytopathic Effect (CPE), morphological changes in host cells upon viral infection, serves as a critical visual indicator of viral load, yet its manual microscopy based assessment is laborious and subjective. Furthermore, simple automated classification often fails to quantify infection severity and struggles with "hard-to-detect" cases. This work presents a comprehensive survey and performance evaluation of various computer vision techniques, ranging from image classification to weakly and strongly supervised segmentation with both classical and deep learning-based models, for the automated detection and localisation of CPE induced by xenotrophic murine leukemia virus (x-MuLV). Our analysis demonstrates that supervised segmentation techniques provide a significantly more robust pathway for viral load quantification than explainability-based classification methods, particularly when analysing images displaying subtle cellular alterations with low viral load. This automated methodology offers an efficient, objective, and scalable alternative to manual inspection, facilitating high-throughput analysis and deeper insights into infection dynamics. Following extensive data preparation, this work systematically compared existing computer vision methodologies, thereby identifying and validating best-performing approaches for consistent and quantitative Cytopathic Effect characterisation, which offers a powerful tool to accelerate drug discovery, advance fundamental viral research, and improve automated virological assays.
Stoma-inspired valve
(Tartu Ülikool, 2023) Makarov, Aleksandr; Must, Indrek, juhendaja
Soft robotics and microfluidics are interdisciplinary fields with shared methods for developing flexible and functional devices. However, manufacturing durable, efficient, and robust devices remains a challenge. One of the key hurdles is the limited number of valve designs available. Currently employed microvalves are either normally closed with negative control pressure or normally open with positive control pressure. However, there has not been a microvalve design reported which is normally closed and has positive control pressure, while it was present for an extended period in nature in the form of a plant stoma. Plant stoma is a robust normally closed valve with positive control pressure, with robustness arising from the fact that when the plant dries the valve closes. It was used as an inspiration source for the valve in this work, which is normally closed and opens at positive as well as negative control pressure, which are improvements over previously reported designs. The findings suggest the potential of this technology for applications ranging from artificial leaves to bioreactors. By considering nature as an inspiration source, a contribution was made towards more sustainable solutions.