121. Strong-form meshless numerical modelling of visco-plastic materialGašper Vuga, Boštjan Mavrič, Božidar Šarler, 2024, original scientific article Abstract: This work extends our research on the strong-form meshless Radial Basis Function - Finite Difference (RBF-FD) method for solving non-linear visco-plastic mechanical problems. The polyharmonic splines with second-order polynomial augmentation are used for the shape functions. Their coefficients are determined by collocation. Three different approaches (direct, composed, and hybrid) are used for the numerical evaluation of the divergence operator in the equilibrium equation. They are presented and assessed for a visco-plastic material model with continuously differentiable material properties. It is shown that the direct approach is not suitable in this respect. In comparison to the previously investigated elasto-plasticity, it is shown that the composed approach can successfully cope with visco-plastic problems and is found to be even more accurate than the hybrid approach, which has previously proven to be most stable and effective in solving elasto-plasticity. This work extends the applicability of strong-form RBF-FD methods and opens up new areas of modelling non-linear solid mechanics.
Keywords: visco-plastic material responses, hybrid radial basis, generated finite differences, polyharmonic splines
Published in DiRROS: 16.12.2024; Views: 68; Downloads: 38
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122. Cytotoxicity assessment of HDPE microplastic on Tetrahymena thermophila (Protozoa, Ciliate) : assuring quality and FAIR dataValentina Perc, Veno Kononenko, Nina Jeliaskova, Matej Hočevar, Slavko Kralj, Darko Makovec, Maja Caf, Damjana Drobne, Sara Novak, 2024, original scientific article Keywords: cytotoxicity, microplastic, HDPE, FAIR data, tetrahymena thermophila
Published in DiRROS: 16.12.2024; Views: 72; Downloads: 39
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123. Preservation of 5-hydroxymethylcytosine levels in LRIG1 across genomic DNA and cell-free DNA in glioma patientsDaša Jevšinek Skok, Luka Bolha, Nina Hauptman, 2024, other scientific articles Abstract: Cell-free DNA (cfDNA) has recently emerged as a promising minimally invasive diagnostic biomarker for various cancers. In this study, our aim was to identify cfDNA biomarkers by investigating genes that displayed significant differences between glioma patients and their corresponding controls. To accomplish this, we utilized publicly available data from the Gene Expression Omnibus, focusing on 5-hydroxymethylcytosine (5hmC) profiles in both cfDNA and genomic DNA (gDNA) from glioma patients and healthy individuals. The intersection of gene lists derived from these comparative analyses unveiled LRIG1 and ZNF703 as the two genes with elevated 5hmC levels in both the cfDNA of glioma patients and gDNA of glioma tissue compared to their respective controls. The gene expression data revealed both genes were upregulated in glioma tissue compared to normal brain tissue. Integration of 5hmC data revealed a strong positive correlation in the glioma tissue group between 5hmC and the gene expression of the LRIG1 gene. Furthermore, exploration using the AmiCa web tool indicated that LRIG1 gene expression was elevated compared to 17 other cancers included in the database, emphasizing its potential as a distinctive biomarker across multiple cancer types.
Keywords: cell-free DNA, glioma, 5-hydroxymethylcytosine, biomarkers
Published in DiRROS: 13.12.2024; Views: 98; Downloads: 39
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125. First report of grapevine leafroll-associated virus 4 infecting grapevine in HungaryR. Olah, M. Turcsan, Nikoletta Jaksa-Czotter, K. Olah, D. A. Nyitrayne Sardi, Irena Mavrič Pleško, Eva Varallyay, 2024, other scientific articles Keywords: grapevine, viruses, leafroll-associated, small RNA sequencing, small RNA high-throughput sequencing, RT-PCR
Published in DiRROS: 13.12.2024; Views: 97; Downloads: 23
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128. Experimental drought results in a decline of ectomycorrhizae of Quercus pubescens Willd.Tanja Mrak, Tina Unuk Nahberger, Olivera Maksimović, Hojka Kraigher, Mitja Ferlan, 2025, original scientific article Abstract: Experimental drought decreased the vitality of ectomycorrhiza and reduced the number of unique morphotypes. Quercus pubescens (Willd.) is an ectomycorrhizal (ECM) tree species that is capable of withstanding occasional drought events, but the response of its ectomycorrhiza to drought is not well known. An experiment with two rain exclusion plots and two natural precipitation regime plots was established in a secondary sub-Mediterranean oak forest. ECM roots were sampled before the experiment and after 11 months of rain exclusion. ECM root tips were divided into vital and non-vital and quantified. Morphoanatomical characterization and molecular identification were performed for vital ectomycorrhizae to obtain diversity indices and perform community analyses. Soil water content (SWC) in rain exclusion plots was reduced by approx. 6 vol.% relative to natural precipitation regime and was devoid of major peaks in SWC after rain events. After 11 months, ECM vitality and species richness were significantly reduced on rain exclusion plots compared to the natural precipitation regime while ECM community was reduced to a small subset of the most frequent morphotypes, with strongly decreased number of the unique morphotypes. The reduction of unique morphotypes as a result of rain exclusion may compromise the functional diversity of ectomycorrhiza in their role of nutrient uptake, while the reduction of ECM vitality may decrease the absorptive surface for water and nutrients.
Keywords: ectomycorrhizal fungi, Pubescent oak, Sub-Mediterranean, karst, drought stress, rain exclusion
Published in DiRROS: 12.12.2024; Views: 92; Downloads: 16
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129. Subjective assessment of sedentary behavior between theory and practice : pilot study using the “Sedentary meter”Ana Cikač, Kaja Teraž, Saša Pišot, 2024, original scientific article Abstract: Although sedentary behavior (SB) is still an under-researched area, some studies have shown a significant association between prolonged sitting and an increased risk of mortality, due to various causes, independent of physical activity. Despite the health risks, there are currently no specific guidelines for individuals to self-assess their SB. A pilot observational study was conducted as part of the “Knowledge for Health” event. A short online quiz “Sedentary meter” was developed, consisting of a pictorial scale to help event participants assess their daily sedentary time and to promote a better understanding of the associated health risks. The quiz questions were formulated based on the WHO definition of SB. The participants’ task was to subjectively estimate the amount of sedentary time in various types of SB on a typical day. The results obtained for SB could then be immediately compared with the figurative scale based on the WHO guidelines. The analysis confirmed SB (533.0±224.7 min/day) in all age groups, although possible differences according to the type of SB were noted. Despite statistically non-significant differences, those between age groups may indicate the extent to which SB can be individualized. The differences between age groups may indicate the importance of considering SB which can be targeted based on each age group's daily routine. The simple tool for accessing SB raised awareness of which specific type of SB accounts for the majority of participants' daily sedentary time. The self-critical acceptance of the “poor results” across all age groups shows the effectiveness of the initiative in raising awareness of SB issues.
Keywords: sedentary behavior, self-assessment, pilot study
Published in DiRROS: 12.12.2024; Views: 116; Downloads: 46
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130. Opt2Vec - a continuous optimization problem representation based on the algorithm's behavior : A case study on problem classificationPeter Korošec, Tome Eftimov, 2024, original scientific article Abstract: Characterization of the optimization problem is a crucial task in many recent optimization research topics (e.g., explainable algorithm performance assessment, and automated algorithm selection and configuration). The state-of-the-art approaches use exploratory landscape analysis to represent the optimization problem, where for each one, a set of features is extracted using a set of candidate solutions sampled by a sampling strategy over the whole decision space. This paper proposes a novel representation of continuous optimization problems by encoding the information found in the interaction between an algorithm and an optimization problem. The new problem representation is learned using the information from the states/positions in the optimization run trajectory (i.e., the candidate solutions visited by the algorithm). With the novel representation, the problem can be characterized dynamically during the optimization run, instead of using a set of candidate solutions from the whole decision space that have never been observed by the algorithm. The novel optimization problem representation is called Opt2Vec and uses an autoencoder type of neural network to encode the information found in the interaction between an optimization algorithm and optimization problem into an embedded subspace. The Opt2Vec representation efficiency is shown by enabling different optimization problems to be successfully identified using only the information obtained from the optimization run trajectory.
Published in DiRROS: 11.12.2024; Views: 84; Downloads: 23
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