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991 - 1000 / 2000
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991.
Paleoenvironmental and neotectonic insights from the pliocene fossil record of Velika Pasica Cave, Slovenia: implications for karst system evolution
Andrej Mihevc, Ivan Horáček, Nadja Zupan Hajna, Jon Woodhead, Anton Brancelj, 2025, original scientific article

Abstract: Velika Pasica Cave, situated on a karst plateau at an altitude of 665 meters above sea level, offers a unique record of paleontological, speleological, and tectonic processes. The cave, predominantly filled with allogenic sediments and speleothems, contains fossilized remains of the aquatic cave invertebrate Marifugia cavatica and terrestrial small mammals, characteristic of the early Pliocene (MN15–16). Paleontological dating estimates the cave sediments to be approximately 4 Ma old, while U/Th dating of the overlying flowstone indicates deposition at 410 ± 21 ka. These findings suggest that stagnant phreatic conditions prevailed prior to tectonic uplift and basin subsidence, which reshaped the karst landscape. This study highlights the dynamic interplay between neotectonics, karst system evolution, and biodiversity changes. By integrating speleobiology, geomorphology, and biostratigraphy, it provides valuable in-sights into the environmental history of the northern Dinarides and the impact of geological processes on karst ecosystems.
Keywords: paleontology, Marifugia cavatica, small mammals, karst geomorphology, cave sediments dating, tectonic
Published in DiRROS: 22.09.2025; Views: 237; Downloads: 135
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992.
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994.
Cathodic arc-deposited AlTiN hard coating tribology at elevated temperatures
Aljaž Drnovšek, Patrik Šumandl, Žan Gostenčnik, Janez Kovač, Miha Čekada, 2025, original scientific article

Abstract: Cathodic arc evaporation (CAE) is the most commonly used physical vapor deposition (PVD) method to deposit protective coatings on cutting and forming tools. However, this deposition method results in a relatively rough surface due to micro-droplet emission. The first contact between the coating and the workpiece surface is at the sites of these growth defects, influencing the state of the contact, such as particle formation and oxidation spots. Growth defects significantly impact the coating's wear and friction properties. Their impact is not limited to the beginning of the contact formation but also expands in the long run, and they can deteriorate the coatings much sooner than expected. This research aims to monitor the wear and friction properties of the cathodic arc deposited AlTiN hard coating during the running-in and steady-state periods under different temperature conditions. Tribological tests against the Al2O3 counterbody were carried out at different temperatures, from room temperature up to 700 °C. The sliding distance at specific temperatures, ranging from 50 to 140,000 cycles, enabled us to monitor the wear progression from first contact formation at the growth defects to the complete coating wear from the WC-Co substrate. After tribological tests, the samples were analyzed using detailed 3D profilometry, SEM, and FIB analysis to determine the wear mechanisms in different stages of high-temperature wear. Attention was focused on the growth defects, their impact on the running-in behavior, and the oxygen diffusion pathways along growth defects that ultimately lead to the delamination of the coating from the substrate.
Keywords: cathodic arc evaporation, physical vapor deposition, growth defects
Published in DiRROS: 19.09.2025; Views: 361; Downloads: 155
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995.
Melanoma antigens in pediatric medulloblastoma contribute to tumor heterogeneity and species-specificity of group 3 tumors
Rebecca R. J. Collins, Rebecca R. Florke Gee, Sima Tozandehjani, Tara Bayat, Maria Camila Hoyos Sanchez, Juan Sebastian Solano Gutierrez, Barbara Breznik, Anna K. Lee, Klementina Fon Tacer, 2025, original scientific article

Abstract: Medulloblastoma (MB) is the most malignant childhood brain cancer. Group 3 MB (G3 MB) subtype accounts for about 25% of MB and is associated with the worst outcomes. Herein, we report that more than half of G3 MB tumors express melanoma antigens (MAGEs), which are potential prognostic and therapeutic markers. MAGEs are cancer‑testis antigens, aberrantly expressed in several adult cancers, and associated with poorer prognosis and therapy resistance; however, their role in pediatric cancers is mostly unknown. This study aimed to determine whether MAGEs are activated and important in pediatric MB. We obtained formalin‑fixed paraffin‑embedded tumor samples of 34 patients, collected between 2008 and 2015 at the Children’s Medical Center in Dallas and applied our validated reverse transcription quantitative PCR (RT‑qPCR) assay to measure the expression of 23 MAGE genes. To validate our data, we analyzed published datasets from pediatric MB tumors and patient‑derived orthotopic xenografts, totaling 949 patients. Our RT‑qPCR analysis suggested that MAGEs were expressed in G3/4MB. Further mining of bulk and single‑cell RNA‑sequencing datasets confirmed that 50–75% of G3 tumors activate several MAGEs. Intriguingly, single‑cell data analysis showed that MAGEs are expressed in distinct subsets of cells in MAGE‑positive tumors and are not activated in mouse genetic models, suggesting they contribute to the tumor heterogeneity and species‑specificity of G3 MB. We then examined how MAGE expression affects the growth and oncogenic potential by CRISPR‑Cas9‑ and siRNA‑mediated gene depletion. Depletion of MAGEAs, ‑B2, and ‑Cs altered cell survival, viability, and clonogenic growth due to decreased proliferation and increased apoptosis of MAGE‑positive MB cells. These findings suggested that targeting MAGEs could represent a viable therapeutic strategy for G3 MB. A deeper understanding of MAGE regulation and function is warranted and could aid in improving prognostic and therapeutic approaches for this poorly characterized subgroup of pediatric brain tumors.
Keywords: medulloblastoma, tumor antigens, MAGE, pediatric cancer, cancer‑testis antigens
Published in DiRROS: 19.09.2025; Views: 317; Downloads: 148
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996.
Transformative change and a sustainable world
Juan Martin Dabezies, Teresia Olemako, Jerneja Penca, Asha Rajvanshi, Roseline Remans, Esther Turnhout, Yuki Yoshida, 2025, independent scientific component part or a chapter in a monograph

Keywords: biodiversity, justice, transformative change, sustainability
Published in DiRROS: 19.09.2025; Views: 279; Downloads: 126
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997.
Re-evaluating restrained shrinkage tests for sustainable sprayed concrete tunnel linings
Zhongyu Xu, Lucija Hanžič, Harry Asche, Jurij Karlovšek, 2025, published scientific conference contribution

Abstract: The demand for tunnelling and underground construction is steadily increasing, alongside growing considerations for carbon emission reduction in tunnelling projects. Using sprayed concrete as a prominent ground support mechanism for the sequential excavation method is also undergoing low-carbon transition with improved resource efficiency. Enhancing the durability of sprayed concrete linings for structural support and water tightness is essential, particularly when used as a permanent lining, replacing conventional cast in-situ concrete for a design life exceeding 100 years. As sprayed concrete is a time-dependent material used in a time-dependent tunnelling environment, restrained shrinkage cracking in tunnel linings is a recognised issue, especially in mined tunnels in shallow or hard-rock ground with minimal ground movement. The susceptibility of sprayed concrete to restrained shrinkage cracking poses challenges to low-carbon transition, impacting the efficacy and longevity of tunnel linings. Excessive crack widths in tunnel projects often lead to non-conformances, requiring time-consuming repairs and affecting project delivery. However, current design methods for permanent sprayed concrete linings inadequately consider the effects of restrained shrinkage, particularly with sprayed concrete containing reinforcement fibres and accelerators. This paper examines the features that should be included in the restrained shrinkage test for tunnel lining applications, and proposes an improvement in detecting crack initiation and determining the optimal number of measurement points form when multiple cracks form with a finite element analysis. The analysis results showed the possibility of detecting the onset of cracking and crack location with multiple measurement points by interpreting the response of each measurement point.
Keywords: tunnel linings, sprayed concrete, restrained shinkage, large ring test
Published in DiRROS: 19.09.2025; Views: 345; Downloads: 144
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998.
Asymmetric T-segment binding and gate dynamics govern the final stages of the type IIA topoisomerase catalytic cycle
Kristina Stevanović, Barbara Herlah, Matic Pavlin, Andrej Perdih, 2025, original scientific article

Abstract: Type IIA DNA topoisomerases are molecular nanomachines that alter DNA topology during essential cellular processes. The final steps of their catalytic cycle, after translocation of the transported (T-) segment into the C- gate, are still not fully understood. Here, we performed all-atom molecular dynamics simulations of several conformational states of Saccharomyces cerevisiae topoisomerase IIA, each with a T-segment inserted into the C- gate. Bound ATP and ADP nucleotides allosterically modulated the N-gate dynamics, likely stabilizing the dimer and preventing premature dissociation. The T-segment was asymmetrically bound and stabilized within the C- gate by positively charged residues, and this gate remained structurally rigid, highlighting its role as a retention site. The positioning of the T-segment in the C-gate allosterically influenced the G-segment to a straighter geometry that favors religation and release. Our simulations support coordinated release of DNA segments and point to a potentially important role for dynamic communication between the gates in the mechanism. These results provide new insights into the late stages of the catalytic cycle and highlight the intertwined roles of nucleotide binding, DNA topology and coupled protein domain dynamics in regulating this important enzyme.
Keywords: type IIA DNA topoisomerase, T-segment, C-gate, catalytic cycle, molecular dynamics
Published in DiRROS: 19.09.2025; Views: 357; Downloads: 167
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999.
Influence of particle size on powder velocity distribution at the nozzle outlet in Directed Energy Deposition
Tijan Mede, Andrej Jeromen, Edvard Govekar, Michael Mallon, Matjaž Godec, 2025, original scientific article

Abstract: Metal-based Directed Energy Deposition (DED) is considered one of the variations of additive manufacturing with the highest potential, particularly for space industry and in-orbital manufacturing. The technology however still faces various challenges, many of which can be traced back to poor control and understanding of the powder delivery. Velocity distribution of powder particles at the DED nozzle outlet has a key influence on the results of any predictive model of powder stream and yet remains largely disputed. Certain numerical studies highlighted a possible influence of powder particle size on the velocity condition at the nozzle exit, yet no experimental studies confirmed this effect. The experimental campaign described in this paper quantifies this relation between powder particle size and velocity distribution at the nozzle outlet and a strong decrease of particle speed with particle size is observed. Moreover, smaller particles are observed to travel at speeds higher than the mean carrier gas speed suggesting powder particle segregation within the nozzle as one of the mechanisms driving speed differences at the nozzle outlet.
Keywords: directed energy deposition, powder stream, boundary conditions, particle velocity distribution
Published in DiRROS: 19.09.2025; Views: 297; Downloads: 141
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1000.
Recycling mineral wool waste : towards sustainable construction materials
Martina Milat, Sandra Juradin, Nives Ostojić-Škomrlj, Anže Tesovnik, 2025, review article

Abstract: This literature review critically examines the incorporation of mineral wool waste (MWW), a byproduct of insulation materials, into new construction materials as a sustainable recycling strategy. Covering research published between 2000 and 2025, the review focuses on the effects of MWW on various material properties and performance, including concrete, mortar, alkali-activated materials (AAMs), geopolymers (GPs), building ceramics, and asphalt. Experimental evidence demonstrates that MWW can enhance or alter the performance of these materials, offering promising opportunities for waste valorization. The review also identifies challenges related to optimizing material compositions and production methods, and highlights the need for further research to facilitate the industrial-scale application of MWW-recycled construction materials. By synthesizing current knowledge, this work aims to inform sustainable development and circular economy practices in the construction sector.
Keywords: mineral wool waste, rock wool, glass wool, recycling, sustainability, construction and demolition waste
Published in DiRROS: 19.09.2025; Views: 313; Downloads: 149
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