1651. Characterization of micro-threaded stem taper surface of cementless hip endoprosthesesDrago Dolinar, Boštjan Kocjančič, Klemen Avsec, Barbara Šetina, Aleksandra Kocijan, Matjaž Godec, Marko Sedlaček, Mojca Debeljak, John T. Grant, Timon Zupanc, Monika Jenko, 2024, original scientific article Abstract: We investigated micro-threaded stem taper surface and its impact on premature failures, aseptic loosening, and infection in cementless hip endoprostheses. Our study focused on the fretting, and crevice corrosion of micro-threaded tapers, as well as the characterization of the microstructure and surface properties of two new and three retrieved Zweymüller stem tapers. The retrieved samples were selected and examined based on the head–stem taper interface being the sole source of modularity with a metallic component, specifically between the Ti alloy taper stem and the ceramic head. To determine the surface chemistry and microstructures of both new and retrieved hip endoprostheses stem taper titanium alloy, scanning -electron microscopy (SEM) was employed for morphological and microstructural analyses. Energy dispersive spectroscopy (EDS) was utilized for characterizing chemical element distribution, and electron backscattered diffraction (EBSD) was used for phase analysis. The roughness of the micro-threated stem tapers from different manufacturers was investigated using an optical profilometer, with standard roughness parameters Ra (average surface roughness) and Rz (mean peak to valley height of the roughness profile) being measured. Electrochemical studies revealed no fretting corrosion in retrieved stem tapers with ceramic heads. Consequently, three retrieved tapers and two new ones for comparison underwent potentiodynamic measurements in Hank’s solution to determine the corrosion rate of new and retrieved stem taper surfaces. The results showed a low corrosion rate for both new and prematurely failed retrieved samples due to aseptic loosening. However, the corrosion rate was higher in infected and low-grade infected tapers. In conclusion, our study suggests that using ceramic heads reduces taper corrosion and subsequently decreases the incidence of premature failures in total hip arthroplasty.
Keywords: total hip arthroplasty, stem micro-threaded taper, taper surface morphology, microstructure, corrosion, Ti implant alloy
Published in DiRROS: 06.06.2024; Views: 390; Downloads: 313
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1652. pISA-tree : a data management framework for life science research projects using a standardised directory treeMarko Petek, Maja Zagorščak, Andrej Blejec, Živa Ramšak, Anna Coll Rius, Špela Baebler, Kristina Gruden, 2022, original scientific article Keywords: pISA-tree, ISA model, data management, research data, metadata
Published in DiRROS: 05.06.2024; Views: 478; Downloads: 723
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1653. Proximity to riverbed influences physiological response of adult pedunculate oak treesLazar Kesić, Matjaž Čater, Saša Orlović, Bratislav Matović, Marko Stojanović, Mirjana Bojović, 2023, original scientific article Abstract: The pedunculate oak (Quercus robur L.) is economically and ecologically one of the most significant tree species in Serbia, however, little is known about the influence of the riverbed distance and its water supply on ecophysiological responses of this species. Given the limited information on the light-response curve of photosynthesis for oaks in southwest Srem, Serbia, the aim of this paper is to enhance understanding of their ecophysiological responses in this context. Maximum assimilation rate (Amax), the quantum yield (Ф), and light compensation point (LCP) were compared in adult trees situated along the transect from the river: (1) close to the river, (2) intermediate, (3) farthest from the river, and (4) forest reserve (second closest), with the first three transects being managed forests and the last one being an unmanaged forest reserve. The measurements were conducted in July during the first evidence of drought. The highest Amax rates were measured in all light intensities on the site closest to the river and the smallest on the site that was most distant to the water source. The most efficient were trees close to the river and the ones in the forest reserve. No significant difference between compensation points was confirmed for the studied groups of trees, although the forest reserve trees showed slightly higher values. The results demonstrated clear response between transects, which followed the distance from the riverbed. Pedunculate oak's reliance on groundwater is in tight relation with ecophysiological processes in trees; groundwater depletion may threaten its survival in areas distant from the river.
Keywords: Quercus robur L., floodplain forest, drought, light-response curves, transects
Published in DiRROS: 05.06.2024; Views: 1475; Downloads: 214
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1654. Relaxations and exact solutions to Quantum Max Cut via the algebraic structure of swap operatorsAdam Bene Watts, Anirban Chowdhury, Aidan Epperly, J. William Helton, Igor Klep, 2024, original scientific article Abstract: The Quantum Max Cut (QMC) problem has emerged as a test-problem for designing approximation algorithms for local Hamiltonian problems. In this paper we attack this problem using the algebraic structure of QMC, in particular the relationship between the quantum max cut Hamiltonian and the representation theory of the symmetric group. The first major contribution of this paper is an extension of non-commutative Sum of Squares (ncSoS) optimization techniques to give a new hierarchy of relaxations to Quantum Max Cut. The hierarchy we present is based on optimizations over polynomials in the qubit swap operators. This is in contrast to the "standard" quantum Lasserre Hierarchy, which is based on polynomials expressed in terms of the Pauli matrices. To prove correctness of this hierarchy, we exploit a finite presentation of the algebra generated by the qubit swap operators. This presentation allows for the use of computer algebraic techniques to manipulate and simplify polynomials written in terms of the swap operators, and may be of independent interest. Surprisingly, we find that level-2 of this new hierarchy is numerically exact (up to tolerance $10^{-7}$) on all QMC instances with uniform edge weights on graphs with at most 8 vertices. The second major contribution of this paper is a polynomial-time algorithm that computes (in exact arithmetic) the maximum eigenvalue of the QMC Hamiltonian for certain graphs, including graphs that can be "decomposed" as a signed combination of cliques. A special case of the latter are complete bipartite graphs with uniform edge-weights, for which exact solutions are known from the work of Lieb and Mattis. Our methods, which use representation theory of the symmetric group, can be seen as a generalization of the Lieb-Mattis result.
Keywords: Quantum Max Cut, swap operators, noncommutative polynomials, symmetric group, Gröbner bases
Published in DiRROS: 04.06.2024; Views: 339; Downloads: 166
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1655. Spremljanje bolnic z ginekološkimi raki po zaključenem zdravljenjuDarja Arko, 2024, published professional conference contribution Abstract: Število žensk, ki so se zdravile zaradi ginekoloških rakov, se veča zaradi staranje populacije, zgodnjega odkrivanja bolezni in bolj uspešnih načinov zdravljenja. Rak in zdravljenje raka prizadenejo ženske na več nivojih, fizično in psihično. Najpogostejše težave so kronične bolečine, utrujenost, limfedem, nevropatija, anksioznost in depresija. Ginekološki raki in njihovo zdravljenje imajo dodatno še pomemben negativen vpliv tudi na spolno življenje. Spremljanje bolnic po zdravljenju raka zato ni namenjeno samo zgodnjemu odkrivanju morebitne ponovitve bolezni, ampak tudi zagotavljanju čim boljše kakovosti življenja. Pomembno in potrebno je, da pri bolnicah po zdravljenju ginekoloških rakov prepoznamo in lajšamo težave, ki so posledica bodisi bolezni same ali pa posledica zdravljenja raka. Načini in organizacija spremljanja bolnic z ginekološkimi raki se močno razlikuje med posameznimi centri in državami, jasnih dokazov, kateri je najboljši način dela, ni. Verjetnost ponovitve bolezni se razlikuje glede na vrsto raka, stadij bolezni, stanje bolnice in glede na to, kako je bila zdravljena, zato je tudi spremljanje smiselno prilagoditi posameznici, kar poudarja večina sodobnih smernic. Ginekološki raki predstavljajo heterogeno skupino bolezni. Mednarodna in domača priporočila o spremljanju so narejena za posamezne lokalizacije in so na kratko predstavljena v prispevku.
Keywords: rak (medicina), ginekologija, ponovitev bolezni, kakovost življenja, strokovna priporočila
Published in DiRROS: 04.06.2024; Views: 378; Downloads: 123
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1656. Zgodnje odkrivanje tveganja nenalezljivih bolezni pri bolnikih z rakom dojk na podlagi umetne inteligence (projekt ARTILLERY)Tomaž Vrtovec, Luka Škrlj, 2024, published scientific conference contribution Abstract: Naraščajoče zbolevanje in izboljšave pri zdravljenju bolnikov z rakom dojk prispevajo tudi k naraščajočemu številu preživelih, ki pa so bolj ogroženi za razvoj drugih kroničnih bolezni, kot so srčno-žilne bolezni, bolezni dihal, povečanje telesne mase in osteoporoza. Ker se večina bolnikov zdravi tudi z radioterapijo, lahko iz slik, pridobljenih z računalniško tomografijo za namene načrtovanja obsevanja, izluščimo tudi informacije o dejavnikih tveganja za druge bolezni. Cilj projekta ARTILLERY v sklopu okvirnega programa Evropske unije Obzorje Evropa je razvoj in vrednotenje zanesljivih in zaupanja vrednih računalniško podprtih sistemov umetne inteligence, ki jih bo mogoče uporabiti na rutinsko pridobljenih računalniško tomografskih slikah za odkrivanje kroničnih bolezni ali njihovih dejavnikov tveganja za namene podaljševanja pričakovane življenjske dobe in izboljšanja kakovosti življenja v naraščajoči populaciji preživelih bolnikov z rakom dojk. V Laboratoriju za slikovne tehnologije na Fakulteti za elektrotehniko Univerze v Ljubljani imamo dolgoletne izkušnje z razvojem in vrednotenjem računalniško podprtih metod za analizo medicinskih slik hrbtenice, zato je naša vloga pri projektu povezana z določanjem tveganja osteoporoze in osteopenije ter razpoznavanjem vretenčnih zlomov. Kljub temu, da je projekt šele v začetni fazi, smo razvili računalniško podprto metodo na osnovi umetne inteligence za segmentacijo hrbtenice in določanje področij zanimanja znotraj vretenčnih teles, na podlagi katerih bomo izluščili informacije o mineralni kostni gostoti ter jo povezali z referenčnimi diagnostičnimi izvidi. Rezultati začetnih raziskav kažejo, da bo razvita metoda potencialno uporabna za zgodnje odkrivanje osteoporoze in osteopenije ter za razpoznavanje vretenčnih zlomov.
Keywords: umetna inteligenca, globoko učenje, analiza medicinskih slik, rak dojke, osteoporoza
Published in DiRROS: 04.06.2024; Views: 537; Downloads: 119
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1657. Podatki o petrologiji pliocensko-pleistocenskih sedimentov severovzhodne SlovenijeEva Mencin Gale, Polona Kralj, Mirka Trajanova, Luka Gale, Dragomir Skaberne, 2024, complete scientific database of research data Abstract: Podatki se nanašajo na petrološko analizo rečnih pliocensko-pleistocenskih sedimentov iz 14 prodnatih vzorcev iz slovenjgraškega, nazarskega, celjskega in dravsko-ptujskega bazena (severovzhodna Slovenija), ki so bili vzorčeni za namen litološke analize klastov. Petrološka analiza obsega opise 155 zbruskov metamorfnih, vulkanskih, vulkanoklastičnih, klastičnih in karbonatnih kamnin. Ti podatki predstavljajo temelj za določitev provenience obravnavanih prodnatih sedimentov, razkrivajo morebitno resedimentacijo ter so pomembni za interpretacijo razvoja rečne mreže v pliocenu in pleistocenu.
Keywords: petrografska analiza, litološka analiza klastov, provenienca klastov, pliocensko-pleistocenski sedimenti
Published in DiRROS: 04.06.2024; Views: 638; Downloads: 592
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1658. Digital PCR for the characterization of reference materialsMegan H. Cleveland, Hua-Jun He, Mojca Milavec, Young-Kyung Bae, Peter M. Vallone, Jim F. Huggett, 2024, review article Abstract: Well-characterized reference materials support harmonization and accuracy when conducting nucleic acid-based tests (such as qPCR); digital PCR (dPCR) can measure the absolute concentration of a specific nucleic acid sequence in a background of non-target sequences, making it ideal for the characterization of nucleic acid-based reference materials. National Metrology Institutes are increasingly using dPCR to characterize and certify their reference materials, as it offers several advantages over indirect methods, such as UV-spectroscopy. While dPCR is gaining widespread adoption, it requires optimization and has certain limitations and considerations that users should be aware of when characterizing reference materials. This review highlights the technical considerations of dPCR, as well as its role when developing and characterizing nucleic acid-based reference materials.
Keywords: digital PCR, dPCR, reference materials, UV-spectroscopy
Published in DiRROS: 03.06.2024; Views: 515; Downloads: 189
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1659. International Conference Religious Conversions and Atheization in 20th Century Central and Eastern Europe : Koper, 22-24 April 20242024, other monographs and other completed works Abstract: Using a broad-based understanding of religious conversions which includes atheization and religious revival, the conference aims to address the issues related to religious transformation in Central and Eastern Europe in the 20th century and different types of religious agency that transcend established norms, legal frameworks and cultural expectations. The speakers will go beyond the usual concept of religious conversion as an exclusively individual, voluntary spiritual phenomenon and will examine conversions that embody the myriad motives, forms, and socio-political particularities which condition the changes of worldviews as a process that frequently encompasses obstacles, pragmatism and profound life alterations. The conference will contribute to wide-ranging but – especially in Central and Eastern Europe – largely unexplored topics from a more nuanced understanding of the mechanisms that drive religious change and religion-state relations.
Taking into account new research perspectives, scholars from the fields of history, anthropology, study of religions, ethnology, sociology, theology and political science will provide new insights into the following topics:
- religious conversions as mechanisms for personal gain, coercive tactics and the (gradual) disestablishment of religious institutions;
- state-imposed atheization processes;
- religious upsurges of (non-)dominant religions, relations between religion and state, and the (re)shaping of religious policies in practise.
Published in DiRROS: 03.06.2024; Views: 383; Downloads: 290
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1660. Distribution of toxigenic cyanobacteria in Alpine lakes and rivers as revealed by molecular screeningMaša Jablonska, Leonardo Cerasino, Adriano Boscaini, Camilla Capelli, Claudia Greco, Aleksandra Krivograd-Klemenčič, Ute Mischke, Nico Salmaso, Rainer Kurmayer, 2024, original scientific article Abstract: The increasing frequency of cyanobacteria blooms in waterbodies caused by ecosystem eutrophication could endanger human health. This risk can be mitigated by effective monitoring incorporating molecular methods. To date, most molecular studies on toxigenic cyanobacteria have been limited to microcystins (MCs), disregarding other cyanotoxins, to freshwater planktic habitats while ignoring benthic habitats, and to limited geographic areas (usually one or a few specific waterbodies). In this study, we used PCR-based methods including PCR product sequencing and chemical-analytical methods (LC-MS/MS) to screen many plankton (n = 123) and biofilm samples (n = 113) originating from 29 Alpine lakes and 18 rivers for their cyanotoxin production potential. Both mcyE (indicating MC synthesis) and anaC (indicating anatoxin (ATX) synthesis) gene fragments were able to qualitatively predict MC or ATX occurrence. The abundance of mcyE gene fragments was significantly related to MC concentrations in plankton samples (R2 = 0.61). mcyE gene fragments indicative of MC synthesis were most abundant in planktic samples (65 %) and were assigned to the genera Planktothrix and Microcystis. However, mcyE rarely occurred in biofilms of lakes and rivers, i.e., 4 % and 5 %, respectively, and were assigned to Microcystis, Planktothrix, and Nostoc. In contrast, anaC gene fragments occurred frequently in planktic samples (14 % assigned to Tychonema, Phormidium (Microcoleus), and Oscillatoria), but also in biofilms of lakes (49 %) and rivers (18 %) and were assigned to the genera Phormidium, Oscillatoria, and Nostocales. The cyrJ gene fragment indicating cylindrospermopsin synthesis occurred only once in plankton (assigned to Dolichospermum), while saxitoxin synthesis potential was not detected. For plankton samples, monomictic and less eutrophic conditions were positively related to mcyE/MC occurrence frequency, while oligomictic conditions were related to anaC/ATX frequency. The anaC/ATX frequency in biofilm was related to the lake habitats generally showing higher biodiversity as revealed from metabarcoding in a parallel study.
Keywords: cyanotoxins, planktic and benthic habitats, water quality monitoring, early warning, toxigenic cyanobacteria, European Alps
Published in DiRROS: 03.06.2024; Views: 528; Downloads: 320
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