1. Graph topological transformations in space-filling cell aggregatesTanmoy Sarkar, Matej Krajnc, 2024, izvirni znanstveni članek Povzetek: Cell rearrangements are fundamental mechanisms driving large-scale deformations of living tissues. In three-dimensional (3D) space-filling cell aggregates, cells rearrange through local topological transitions of the network of cell-cell interfaces, which is most conveniently described by the vertex model. Since these transitions are not yet mathematically properly formulated, the 3D vertex model is generally difficult to implement. The few existing implementations rely on highly customized and complex software-engineering solutions, which cannot be transparently delineated and are thus mostly non-reproducible. To solve this outstanding problem, we propose a reformulation of the vertex model. Our approach, called Graph Vertex Model (GVM), is based on storing the topology of the cell network into a knowledge graph with a particular data structure that allows performing cell-rearrangement events by simple graph transformations. Importantly, when these same transformations are applied to a two-dimensional (2D) polygonal cell aggregate, they reduce to a well-known T1 transition, thereby generalizing cell-rearrangements in 2D and 3D space-filling packings. This result suggests that the GVM’s graph data structure may be the most natural representation of cell aggregates and tissues. We also develop a Python package that implements GVM, relying on a graph-database-management framework Neo4j. We use this package to characterize an order-disorder transition in 3D cell aggregates, driven by active noise and we find aggregates undergoing efficient ordering close to the transition point. In all, our work showcases knowledge graphs as particularly suitable data models for structured storage, analysis, and manipulation of tissue data. Ključne besede: 3D vertex models, cell, software-engineering Objavljeno v DiRROS: 03.09.2024; Ogledov: 97; Prenosov: 1363 Celotno besedilo (2,62 MB) Gradivo ima več datotek! Več... |
2. Imaging of human glioblastoma cells and their interactions with mesenchymal stem cells in the zebrafish (Danio rerio) embryonic brainMiloš Vittori, Barbara Breznik, Tajda Gredar, Katja Hrovat, Lilijana Bizjak-Mali, Tamara Lah Turnšek, 2016, izvirni znanstveni članek Povzetek: Background
An attractive approach in the study of human cancers is the use of transparent zebrafish (Danio rerio) embryos, which enable the visualization of cancer progression in a living animal.
Materials and methods
We implanted mixtures of fluorescently labeled glioblastoma (GBM) cells and bonemarrow-derived mesenchymal stem cells (MSCs) into zebrafish embryos to study the cellular pathways of their invasion and the interactions between these cells in vivo.
Results
By developing and applying a carbocyanine-dye-compatible clearing protocol for observation of cells in deep tissues, we showed that U87 and U373 GBM cells rapidly aggregated into tumor masses in the ventricles and midbrain hemispheres of the zebrafish embryo brain, and invaded the central nervous system, often using the ventricular system and the central canal of the spinal cord. However, the GBM cells did not leave the central nervous system. With co-injection of differentially labeled cultured GBM cells and MSCs, the implanted cells formed mixed tumor masses in the brain. We observed tight associations between GBM cells and MSCs, and possible cell-fusion events. GBM cells and MSCs used similar invasion routes in the central nervous system.
Conclusions
This simple model can be used to study the molecular pathways of cellular processes in GBM cell invasion, and their interactions with various types of stromal cells in double or triple cell co-cultures, to design anti-GBM cell therapies that use MSCs as vectors. Ključne besede: brain tumors, tumor microenvironment, animal models, xenotransplantation Objavljeno v DiRROS: 25.07.2024; Ogledov: 192; Prenosov: 178 Celotno besedilo (1,35 MB) Gradivo ima več datotek! Več... |
3. A ǂFramework for applying data-driven AI/ML models in reliabilityRok Hribar, Margarita Antoniou, Gregor Papa, 2024, samostojni znanstveni sestavek ali poglavje v monografski publikaciji Povzetek: In this chapter, we present a framework for applying artificial intelligence (AI)/machine learning (ML) in reliability, in the context of the iRel40 project. Data-driven models are becoming an increasingly fruitful tool for detecting patterns in complex data and identifying the circumstances in which they occur. Using only data, gathered along the value chain, data-driven methods are now being used to detect indications of potential early failures, signs of wear out or degradation, and other unwanted events within the development, fabrication, or service phases of the electronic components and systems. We present general considerations that were found to be important during the iRel40 project, when designing pipelines that combine data processing with the AI/ML models for predicting or detecting reliability issues. This chapter serves as an introduction to the definitions and concepts used within the specific use cases that rely on the AI/ML methodology within the iRel40 project. Ključne besede: machine learning, artificial intelligence, data-driven models Objavljeno v DiRROS: 23.07.2024; Ogledov: 137; Prenosov: 57 Povezava na datoteko |
4. Reliability improvements for in-wheel motorGašper Petelin, Rok Hribar, Stane Ciglarič, Jernej Herman, Anton Biasizzo, Peter Korošec, Gregor Papa, 2024, samostojni znanstveni sestavek ali poglavje v monografski publikaciji Povzetek: Setting up a reliable electric propulsion system in the automotive sector requires an intelligent condition monitoring device capable of reliably assessing the state and the health of the electric motor. To allow for a massive integration of such monitoring devices, they must be inexpensive and small. These requirements limit their accuracy. However, we show in this chapter that these limitations can be significantly reduced by appropriate processing of the sensor data. We have used machine learning models (random forest and XGBoost) to transform very noisy motor winding insulation resistance measurements made by a low-cost device into a much more reliable value that can compete with measurements made by a high-priced state-of-the-art measurement system. The proposed method is an important building block for a future smart condition monitoring system and enables a cost-effective and accurate assessment of the condition of electric motor health in connection with the condition of their winding insulation. Ključne besede: machine learning models, low-cost device, electric motor Objavljeno v DiRROS: 23.07.2024; Ogledov: 172; Prenosov: 77 Povezava na datoteko |
5. Multi-platform, high-resolution study of a complex coastal system : the TOSCA experiment in the Gulf of TriesteStefano Querin, Simone Cosoli, Riccardo Gerin, Célia Laurent, Vlado Malačič, Neva Pristov, Pierre-Marie Poulain, 2021, izvirni znanstveni članek Povzetek: Abstract
Although small in size, the Gulf of Trieste (GoT), a marginal coastal basin in the northern Adriatic Sea, is characterized by very complex dynamics and strong variability of its oceanographic conditions. In April–May 2012, a persistent, large-scale anticyclonic eddy was observed in the GoT. This event was captured by both High Frequency Radar (HFR) and Lagrangian drifter observations collected within the European MED TOSCA (Tracking Oil Spill and Coastal Awareness) project. The complexity of the system and the variety of forcing factors constitute major challenges from a numerical modeling perspective when it comes to simulating the observed features. In this study, we implemented a high-resolution hydrodynamic model in an attempt to reproduce and analyze the observed basin-wide eddy structure and determine its drivers. We adopted the Massachusetts Institute of Technology General Circulation Model (MITgcm), tailored for the GoT, nested into a large-scale simulation of the Adriatic Sea and driven by a tidal model, measured river freshwater discharge data and surface atmospheric forcing. Numerical results were qualitatively and quantitatively evaluated against HFR surface current maps, Lagrangian drifter trajectories and thermohaline data, showing good skills in reproducing the general circulation, but failing in accurately tracking the drifters. Model sensitivity to different forcing factors (wind, river and tides) was also assessed. Ključne besede: Adriatic Sea, surface circulation, HF coastal radars, Lagrangian drifters, wind-driven currents, ocean circulation models Objavljeno v DiRROS: 19.07.2024; Ogledov: 213; Prenosov: 164 Celotno besedilo (7,95 MB) Gradivo ima več datotek! Več... |
6. Breast cancer risk based on adapted IBIS prediction model in Slovenian women aged 40-49 years : coul it be better?Tjaša Oblak, Vesna Zadnik, Mateja Krajc, Katarina Lokar, Janez Žgajnar, 2020, izvirni znanstveni članek Ključne besede: breast surgery, IBIS, prediction models, risk factors Objavljeno v DiRROS: 12.07.2024; Ogledov: 169; Prenosov: 68 Celotno besedilo (286,49 KB) |
7. Imaging of human glioblastoma cells and their interactions with mesenchymal stem cells in the zebrafish (Danio rerio) embryonic brainMiloš Vittori, Barbara Breznik, Tajda Gredar, Katja Hrovat, Lilijana Bizjak-Mali, Tamara Lah Turnšek, 2016, izvirni znanstveni članek Ključne besede: brain tumors, tumor microenvironment, animal models, xenotransplantation Objavljeno v DiRROS: 09.05.2024; Ogledov: 297; Prenosov: 516 Celotno besedilo (1,35 MB) |
8. Qualitative analysis of the minimal Higgins model of glycolysisBrigita Ferčec, Matej Mencinger, Tatjana Petek, Orhan Ozgur Aybar, Ilknur Kusbeyzi Aybar, 2023, izvirni znanstveni članek Povzetek: Glycolysis, one of the leading metabolic pathways, involves many
different periodic oscillations emerging at positive steady states of
the biochemical models describing this essential process. One of
the models employing the molecular diffusion of intermediates is
the Higgins biochemical model to explain sustained oscillations. In
this paper, we investigate the center-focus problem for the minimal
Higgins model for general values of the model parameters with the
help of computational algebra. We demonstrate that the model
always has a stable focus point by finding a general form of the first
Lyapunov number. Then, varying two of the model parameters, we
obtain the first three coefficients of the period function for the stable focus point of the model and prove that the singular point is actually a bi-weak monodromic equilibrium point of type $[1, 2]$. Additionally, we prove that there are two (small) intervals for a chosen parameter $a > 0$ for which one critical period bifurcates from this singular point after small perturbations. Ključne besede: biological processes, biochemical models, glycolysis Objavljeno v DiRROS: 18.03.2024; Ogledov: 360; Prenosov: 158 Celotno besedilo (837,28 KB) Gradivo ima več datotek! Več... |
9. Enhancing circular business model implementation in pulp and paper industry (PPI) : a phase-based implementation guide to waste valorisation strategiesaAmaia Sopelana, Asier Oleaga, Juan José Cepriá, Karmen Fifer Bizjak, Helena Paiva, Francisco-Javier Rios-Davila, Adriana H. Martinez, Antonio Cañas, 2023, izvirni znanstveni članek Povzetek: Innovation in the circular economy (CE) and the deployment of effective circular business models (CBM) have attracted significant attention in times of growing natural resource scarcity. Despite this widespread interest, significant challenges remain between theoretical innovations and effective CBM implementation in any industrial sector where companies pursue cost-saving opportunities through waste valorisation strategies. Since current methods mislead in terms of the real limitations to designing feasible novel products and services under a circular economy, this study proposes exploring determinants underpinning the organisational resilience of CBMs under a resource efficiency strategy through three case studies. As a result of a co-creation process, the implementation of a CBM framework was built upon empirical data and, thence, a phase-based implementation guide was laid out to assist companies in designing and implementing innovative CBM dealing with the complexity of innovative waste valorisation strategies between the PPI and construction sectors. Relevant findings on managerial and policy recommendations encountered along the demo stage are provided in this paper favouring an effective implementation of CE strategies: the role of technological and non-technological aspects within the CBM, the perspective of the ecosystem and its value proposition, and specific guidelines for the different phases of CBM life cycle. Ključne besede: circular business models (CBMs), resource recovery, waste valorisation, strategic management, pulp and paper industry (PPI), construction sector Objavljeno v DiRROS: 13.12.2023; Ogledov: 458; Prenosov: 221 Celotno besedilo (1,06 MB) Gradivo ima več datotek! Več... |
10. Assessing the generalizability of a performance predictive modelAna Nikolikj, Gjorgjina Cenikj, Gordana Ispirova, Diederick Vermetten, Ryan Dieter Lang, Andries Petrus Engelbrecht, Carola Doerr, Peter Korošec, Tome Eftimov, 2023, objavljeni znanstveni prispevek na konferenci Ključne besede: algorithms, predictive models, machine learning Objavljeno v DiRROS: 15.09.2023; Ogledov: 604; Prenosov: 380 Celotno besedilo (935,67 KB) Gradivo ima več datotek! Več... |