Research outputs from Pure / Zinātniskās darbības rezultāti no ZDIS Pure

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Browsing Research outputs from Pure / Zinātniskās darbības rezultāti no ZDIS Pure by Subject "1.1 Mathematics"

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    Brain connections analysis using graph theory measures
    (Rēzeknes Tehnoloģiju akadēmija, 2019) Minejeva, O.; Markovics, Z.; Zdanovskis, Nauris; Rīga Stradiņš University
    Brain is a part of the organism’s complex structure that performs many functions, which are responsible for the main human abilities: to talk, to hear, to move, to see, etc. The brain consists of several areas that are not only directly connected with the different body systems, but also depend and may affect each other. Researchers and doctors are trying to summarize and visualize these relationships for an important purpose – to get the information about possible reactions of the body in case of various diseases, possibilities of recovery, risks, etc. important issues. Neurologists are looking for ways to “move” through the brain in virtual space for viewing the synapses between different areas. It might be useful to get a general idea of how brain regions are interrelated. The term “connectome”, which is the complete structural description of the brain connections, or the map of connections, is used for the common perception of brain relationships. Connectome is a network of thousands of nerve fibres that transmits signals between the special regions responsible for functions such as vision, hearing, movement and memory, and combines these functions in a system that perceives, decides and acts as a whole. So, the relationships of brain neural regions can be represented as a graph with vertices corresponding to specific areas, but edges are links between these areas. This graph can be analysed using quantitative measures, like node degree, centrality, modularity etc. This article discusses the different network measures for the connections between brain’s regions. The purpose is to determine the most important areas andthe role of individual connections in the general functional brain model.
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    Human–robot collaboration trends and safety aspects : A systematic review
    (2021-09) Arents, Janis; Abolins, Valters; Judvaitis, Janis; Vismanis, Oskars; Oraby, Aly; Ozols, Kaspars
    Smart manufacturing and smart factories depend on automation and robotics, whereas human–robot collaboration (HRC) contributes to increasing the effectiveness and productivity of today’s and future factories. Industrial robots especially in HRC settings can be hazardous if safety is not addressed properly. In this review, we look at the collaboration levels of HRC and what safety actions have been used to address safety. One hundred and ninety-three articles were identified from which, after screening and eligibility stages, 46 articles were used for the extraction stage. Predefined parameters such as: devices, algorithms, collaboration level, safety action, and standards used for HRC were extracted. Despite close human and robot collaboration, 25% of all reviewed studies did not use any safety actions, and more than 50% did not use any standard to address safety issues. This review shows HRC trends and what kind of functionalities are lacking in today’s HRC systems. HRC systems can be a tremendously complex process; therefore, proper safety mechanisms must be addressed at an early stage of development.
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    The role of Strontium enriched hydroxyapatite and tricalcium phosphate biomaterials in osteoporotic bone regeneration
    (2019-02-01) Zarins, Janis; Pilmane, Mara; Sidhoma, Elga; Salma, Ilze; Locs, Janis; Institute of Anatomy and Anthropology; Department of Oral and Maxillofacial Surgery and Oral Medicine
    Background: Strontium (Sr) enriched biomaterials have been used to improve bone regeneration in vivo. However, most studies provide only two experimental groups. The aim of our study was to compare eleven different bone sample groups from osteoporotic and healthy rabbits' femoral neck, as it is the most frequent osteoporotic fracture in humans. Methods: Osteoporotic bone defects were filled with hydroxyapatite 30% (HA) and tricalcium phosphate 70% (TCP), 5% Sr-enriched HA 30 /TCP 70 , HA 70 /TCP 30 , or Sr-HA 70 /TCP 30 granules and were compared with intact leg, sham surgery and healthy non-operated bone. Expression of osteoprotegerin (OPG), nuclear factor kappa beta 105 (NFkB-105), osteocalcin (OC), bone morphogenetic protein 2/4 (BMP-2/4), collagen I (Col-1α), matrix metalloproteinase 2 (MMP- 2), tissue inhibitor of matrix metalloproteinase 2 (TIMP-2), interleukin 1 (IL-1) and interleukin 10 (IL-10) was analyzed by histomorphometry and immunohistochemistry. Results: Our study showed that Sr-HA 70 /TCP 30 induced higher expression of all above-mentioned factors compared to intact leg and even higher expression of OC, MMP-2 and NFkB-105 compared to Sr-HA 30 /TCP 70 . HA 70 /TCP 30 induced higher level of NFkB-105 and IL-1 compared to HA 30 /TCP 70 . Conclusion: Sr-enriched biomaterials improved bone regeneration at molecular level in severe osteoporosis and induced activity of the factors was higher than after pure ceramic, sham or even healthy rabbits.