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Keywords: intracranial aneurysms, enovascular embolization, perianeurysmal oedema, hypertension
Published in DiRROS: 16.04.2024; Views: 11; Downloads: 2
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Keywords: gozdarstvo, les, makro analize, mikro analize, javor, identifikacija
Published in DiRROS: 15.04.2024; Views: 32; Downloads: 3
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Abstract: We consider persistent homology obtained by applying homology to the open Rips filtration of a compact metric space $(X, d)$. We show that each decrease in zero-dimensional persistence and each increase in one-dimensional persistence is induced by local minima of the distance function $d$ When $d$ attains local minimum at only finitely many pairs of points, we prove that each above mentioned change in persistence is induced by a specific critical edge in Rips complexes, which represents a local minimum of $d$. We use this fact to develop a theory (including interpretation) of critical edges of persistence. The obtained results include upper bounds for the rank of one-dimensional persistence and a corresponding reconstruction result. Of potential computational interest is a simple geometric criterion recognizing local minima of $d$ that induce a change in persistence. We conclude with a proof that each locally isolated minimum of $d$ can be detected through persistent homology with selective Rips complexes. The results of this paper offer the first interpretation of critical scales of persistent homology (obtained via Rips complexes) for general compact metric spaces.
Keywords: persistent homology, Rips complex, critical simplex, reconstruction result
Published in DiRROS: 10.04.2024; Views: 52; Downloads: 23
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Abstract: Background. Several methods that are currently used for contouring analysis have problems providing reliable and/ or meaningful results. In this paper a solution to these problems is proposed in a form of a novel measure, which was developed based on requirements defined for contouring studies. Materials and methods. The proposed distance deviation measure can be understood as an extension of the closest point measures in such a way that it does not measure only distances between points on contours but rather analyse deviation of distances to both/all contours from each image point/voxel. The obtained result is information rich, reliable and provided in a form of an image, enabling detailed topographic analysis. In addition to image representation, results can be further processed into angular representation for compact topographic analysis or into overall scalar estimates for quick assessment of contour disagreement. Results. Distance deviation method is demonstrated on a multi observer contouring example with complex contour shapes, i.e., with pronounced extremes and void interior. The results are presented using the three proposed methods. Conclusions. The proposed method can detect and measure contour variation irrespective of contour complexity and number of contour segments, while the obtained results are easy to interpret. It can be used in various situations, regarding the presence of reference contour or multiple test contours.
Keywords: contouring, contour comparison, distance transform
Published in DiRROS: 03.04.2024; Views: 56; Downloads: 16
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Abstract: Background. Cancer has traditionally been considered as a disease resulting from gene mutations. New findings in biology are challenging gene-centered explanations of cancer progression and redirecting them to the non-genetic origins of tumorigenicity. It has become clear that intercellular communication plays a crucial role in cancer progression. Among the most intriguing ways of intercellular communication is that via extracellular vesicles (EVs). EVs are membrane structures released from various types of cells. After separation from the mother membrane, EVs become mobile and may travel from the extracellular space to blood and other body fluids. Conclusions. Recently it has been shown that tumour cells are particularly prone to vesiculation and that tumour-derived EVs can carry proteins, lipids and nucleic acids causative of cancer progression. The uptake of tumour-derived EVs by noncancerous cells can change their normal phenotype to cancerous. The suppression of vesiculation could slow down tumour growth and the spread of metastases. The purpose of this review is to highlight examples of EV-mediated cancer phenotypic transformation in the light of possible therapeutic applications.
Published in DiRROS: 03.04.2024; Views: 53; Downloads: 24
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