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Abstract: Let $p\in\mathbb{N}$ and $q\in\mathbb{N}\cup\{\infty\}$. We study a dynamic coloring of the vertices of a graph $G$ that starts with an initial subset $S$ of blue vertices, with all remaining vertices colored white. If a white vertex $v$ has at least $p$ blue neighbors and at least one of these blue neighbors of $v$ has at most $q$ white neighbors, then by the spreading color change rule the vertex $v$ is recolored blue. The initial set $S$ of blue vertices is a $(p,q)$-spreading set for $G$ if by repeatedly applying the spreading color change rule all the vertices of $G$ are eventually colored blue. The $(p,q)$-spreading set is a generalization of the well-studied concepts of $k$-forcing and $r$-percolating sets in graphs. For $q\ge2$, a $(1,q)$-spreading set is exactly a $q$-forcing set, and the $(1,1)$-spreading set is a $1$-forcing set (also called a zero forcing set), while for $q=\infty$, a $(p,\infty)$-spreading set is exactly a $p$-percolating set. The $(p,q)$-spreading number, $\sigma_{(p,q)}(G)$, of $G$ is the minimum cardinality of a $(p,q)$-spreading set. In this paper, we study $(p,q)$-spreading in claw-free cubic graphs. While the zero-forcing number of claw-free cubic graphs was studied earlier, for each pair of values $p$ and $q$ that are not both $1$ we either determine the $(p,q)$-spreading number of a claw-free cubic graph $G$ or show that $\sigma_{(p,q)}(G)$ attains one of two possible values.
Keywords: bootstrap percolation, zero forcing set, k-forcing set, spreading
Published in DiRROS: 23.09.2025; Views: 218; Downloads: 104
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Published in DiRROS: 22.09.2025; Views: 311; Downloads: 207
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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: 236; Downloads: 132
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Published in DiRROS: 22.09.2025; Views: 272; Downloads: 120
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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: 312; Downloads: 143
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