1. Ingenious architecture and coloration generation in enamel of Rodent teethVesna Šrot, Sophia Houari, Gregor Kapun, Birgit Bußmann, Felicitas Predel, Boštjan Pokorny, Elena Bužan, Ute Salzberger, Bernhard Fenk, Marion Kelsch, Peter van Aken, 2024, original scientific article Abstract: Teeth exemplify architectures comprising an interplay of inorganic and organic constituents, resulting in sophisticated natural composites. Rodents (Rodentia) showcase extraordinary adaptations, with their continuously growing incisors surpassing human teeth in functional and structural optimizations. In this study, employing state-of-the-art direct atomic-scale imaging and nanoscale spectroscopies, we present compelling evidence that the release of material from ameloblasts and the subsequent formation of iron-rich enamel and surface layers in the constantly growing incisors of rodents are complex orchestrated processes, intricately regulated and independent of environmental factors. The synergistic fusion of three-dimensional tomography and imaging techniques of etched rodent́s enamel unveils a direct correlation between the presence of pockets infused with ferrihydrite-like material and the acid resistant properties exhibited by the iron-rich enamel, fortifying it as an efficient protective shield. Moreover, observations using optical microscopy shed light on the role of iron-rich enamel as a microstructural element that acts as a path for color transmission, although the native color remains indistinguishable from that of regular enamel, challenging the prevailing paradigms. The redefinition of “pigmented enamel” to encompass ferrihydrite-like infusion in rodent incisors reshapes our perception of incisor microstructure and color generation. The functional significance of acid-resistant iron-rich enamel and the understanding of the underlying coloration mechanism in rodent incisors have far-reaching implications for human health, development of potentially groundbreaking dental materials, and restorative dentistry. These findings enable the creation of an entirely different class of dental biomaterials with enhanced properties, inspired by the ingenious designs found in nature.
Keywords: teeth microstructure, ameloblasts, ferritin, Fe-rich enamel, tomography, rodent
Published in DiRROS: 26.04.2024; Views: 12; Downloads: 4
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3. How beech provenance affects the structure of secondary xylem, leaf traits, and the ectomycorrhizal community under optimal growth conditionsTanja Mrak, Jožica Gričar, Tina Unuk Nahberger, Gregor Božič, Luka Krajnc, Peter Prislan, Domen Arnič, Tom Levanič, Hojka Kraigher, 2024, original scientific article Abstract: Beyond growth parameters and drought tolerance, comparatively little is known about the functioning of different beech (Fagus sylvatica L.) provenances. We investigated properties of leaves, stem secondary xylem, and ectomycorrhiza (ECM), and explored their interdependencies to identify the best performing beech provenance in optimal growth conditions. The study was conducted on 23-year-old trees in a provenance trial. The investigated provenances originated from Atlantic (Belgium—BE), Alpine (Italy—IT, Slovenia—SI), and continental climates (the Czech Republic—CZ). A significant effect of provenance was observed for stem vessel diameters and conductive area, as well as for foliar %C, δ13C, δ15N, and δ18O. δ13C as a proxy of intrinsic water use efficiency (iWUE) showed that the highest iWUE was achieved in BE provenance. Individuals with a better iWUE had wider growth rings regardless of provenance. Better iWUE was associated with lower specific leaf area (SLA). ECM community composition and diversity indices did not differ significantly among the provenances. Specific ECM taxa were associated with individuals with high SLA, δ13C, δ15N, and δ18O. In optimal growth conditions with no stress events, BE is a promising provenance due to an efficient water conducting system with high vessel diameters and conductive area, and high iWUE, while Alpine provenances showed an adaptation of their water conducting system to freezing conditions at their original locations. Integrating findings from different compartments improves our understanding of functioning of different beech provenances.
Keywords: Fagus sylvatica, provenance trial, stable isotopes, specific leaf area, xylem vessels, ectomycorrhizal fungi
Published in DiRROS: 19.04.2024; Views: 68; Downloads: 32
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4. Analysis of risk factors for perifocal oedema after endovascular embolization of unruptured intracranial arterial aneurysmsSnezana Lukic, Slobodan Janković, Katarina Šurlan Popović, Dušan Dragič Banković, Peter Popović, Milan Mijailović, 2015, original scientific article Keywords: intracranial aneurysms, enovascular embolization, perianeurysmal oedema, hypertension
Published in DiRROS: 16.04.2024; Views: 65; Downloads: 21
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6. Poročilo : Makro in mikro analiza vzorcev lesa za identifikacijo (javor)Jožica Gričar, Gregor Skoberne, Peter Prislan, 2024, treatise, preliminary study, study Keywords: gozdarstvo, les, makro analize, mikro analize, javor, identifikacija
Published in DiRROS: 15.04.2024; Views: 88; Downloads: 25
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7. The Waring problem for matrix algebras, IIMatej Brešar, Peter Šemrl, 2023, original scientific article Abstract: Let $f$ be a noncommutative polynomial of degree $m\ge 1$ over an algebraically closed field $F$ of characteristic $0$. If $n\ge m-1$ and $\alpha_1,\alpha_2,\alpha_3$ are nonzero elements from $F$ such that $\alpha_1+\alpha_2+\alpha_3=0$, then every trace zero $n\times n$ matrix over $F$ can be written as $\alpha_1 A_1+\alpha_2A_2+\alpha_3A_3$ for some $A_i$ in the image of $f$ in $M_n(F)$.
Keywords: Waring problem, noncommutatative polynomials, matrix algebras
Published in DiRROS: 10.04.2024; Views: 64; Downloads: 28
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8. Critical edges in Rips complexes and persistencePeter Goričan, Žiga Virk, 2023, original scientific article 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: 57; Downloads: 31
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9. Sliding wear behaviour of conventional and cryotreated PM Cr-V (Vanadis 6) ledeburitic tool steelVenu Yarasu, Peter Jurči, Peter Gogola, Bojan Podgornik, Marko Sedlaček, 2023, original scientific article Keywords: cold work tool steel, conventional treatment, cryogenic treatment, hardness, reciprocal sliding, wear
Published in DiRROS: 08.04.2024; Views: 91; Downloads: 19
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10. Distance deviation measure of contouring variabilityPeter Rogelj, Robert Hudej, Primož Petrič, 2013, original scientific article 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: 66; Downloads: 23
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