1561. Biocompatible polyelectrolyte multilayers with copper oxide and zinc oxide nanoparticles for inhibiting bacterial growthNives Matijaković Mlinarić, Stefanie Altenried, Atiđa Selmani, Juraj Nikolić, Aleksander Učakar, Anamarija Zore, Anže Abram, Sandro Lehner, Andrijana Sever Škapin, Monika Kušter, Eva Roblegg, Davor Kovačević, Qun Ren, Klemen Bohinc, 2024, original scientific article Abstract: The prevalence of bacterial infections presents a significant challenge in the medical field, demanding effective strategies to impede bacterial adhesion and growth on various surfaces. The conducted study investigates the efficacy of polyelectrolyte multilayers─comprising poly(allylamine hydrochloride) (PAH) and alginate (ALG)─embedded with zinc oxide (ZnO) and copper oxide (CuO) nanoparticles (NPs) to inhibit bacterial adhesion on stainless-steel surfaces. Surface characterization involved zeta potential, contact angle, and roughness assessments. The effect of NP composition, size, and morphology in conjunction with polycation or polyanion terminating multilayers was evaluated against planktonic and surface-adhered Escherichia coli (E. coli) cells. Surfaces with the positively charged PAH-terminating multilayer displayed higher water contact angles (≈ 63°) than the negatively charged ALG-terminating multilayers (≈ 45°). Multilayers containing ZnO NPs showed a significant inhibition of planktonic E. coli growth, >99%. Moreover, complete growth inhibition of surface-adhered E. coli was achieved for multilayers containing both ZnO and CuO. Due to their larger specific surface area, rod-like ZnO NPs displayed higher antibacterial activity. The samples with ALG as the terminating layer showed more substantial antibacterial properties than samples with PAH as the terminating layer. Biocompatibility tests on immortalized human keratinocyte cells revealed good compatibility with multilayers incorporating NPs. In summary, this study underscores the potential of ZnO and CuO NPs within PAH/ALG multilayers for antibacterial applications without compromising their cytocompatibility.
Keywords: polyelectrolyte multilayers, alginate, poly(allylamine hydrochloride), CuO, ZnO, nanoparticles, Escherichia coli
Published in DiRROS: 06.06.2024; Views: 389; Downloads: 326
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1562. Prepoznavanje ogroženosti za nastanek raka dojk na mamografskih slikahŽan Klaneček, Andrej Studen, Katja Jarm, Mateja Krajc, Miloš Vrhovec, Robert Jeraj, 2024, published professional conference contribution Abstract: Za prehod s populacijskega na personalizirano presejanje za raka dojk je v prvi vrsti potrebno natančno prepoznavanje ogroženosti za razvoj raka dojk. Standardni modeli, ki temeljijo na klasičnih značilkah, niso najbolj zanesljivi. Z razvojem umetne inteligence, predvsem na področju globokega učenja, se je izkazalo, da modeli, ki so naučeni na mamografskih slikah, dosegajo signifikantno boljše rezultate pri napovedovanju ogroženosti. Trenutno je najboljši model za napovedovanje ogroženosti MIRAI, ki je bil uspešno validiran na različnih populacijah. A vendar so rezultati še daleč od popolnih in možnosti za izboljšave je ogromno, predvsem na področju razširitve uporabnosti modela za različne proizvajalce mamografskih aparatov, vključevanja longitudinalnih sprememb in uporabe segmentiranih slik dojke.
Keywords: obvladovanje raka, presejalni programi, rak dojk, mamografija
Published in DiRROS: 06.06.2024; Views: 455; Downloads: 156
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1563. Napovedovanje neželenih učinkov pri imunoterapiji metastatskega melanoma na podlagi slik FDG-PETKatja Strašek, Martina Reberšek, 2024, published professional conference contribution Abstract: Imunoterapija je preoblikovala zdravljenje metastatskih rakov, saj je izboljšala preživetje in kakovost življenja bolnikov. Kljub temu povzroča imunsko pogojene neželene učinke, ki zahtevajo prekinitev zdravljenja. Njihovo zgodnje odkrivanje je zato ključnega pomena, njihova diagnoza pa temelji predvsem na kliničnih simptomih in laboratorijskih izvidih. Razmah razvoja umetne inteligence v preteklih letih je omogočil bolj kvantitativno analizo 18F-FDG PET/CT slik. Prvi korak, kjer umetna inteligenca pripomore k hitrejši diagnozi imunsko pogojenih neželenih učinkov, so nevronske mreže, razvite za segmentacijo organov na CT-slikah. Uporaba takšnih avtomatskih orodij za segmentacijo organov je hitrejša in bolj natančna v primerjavi z ročno segmentacijo. Omogoča tudi razvoj kvantitativnih slikovnih bioloških označevalcev, izvlečenih iz PET-slik s pomočjo pridobljenih segmentacij, kar je pripomoglo tudi k razmahu razvoja napovednih modelov. V retrospektivni raziskavi, ki je vključevala 58 bolnikov z metastatskim melanomom, so se percentili porazdelitve FDG v ščitnici, črevesju in pljučih izkazali kot orodje za ločevanje med bolniki, ki bodo razvili imunsko pogojene neželene učinke, in tistimi, ki jih ne bodo. Validacija teh kvantitativnih slikovnih bioloških označevalcev (angl. Quantitative Imaging Biomarkers, QIB) za napovedovanje imunsko pogojenih neželenih učinkov trenutno poteka v prospektivni neinterventni klinični raziskavi na Onkološkem inštitutu Ljubljana. Prvi izsledki kažejo, da so razviti označevalci v pomoč klinikom pri zgodnji diagnozi imunsko pogojenih neželenih učinkov, kar omogoči hitrejše ukrepanje pred razvojem kliničnih simptomov, a včasih tudi lažno napovedo možen razvoj neželenih učinkov. Naslednji koraki so razvoj modela za napoved časa razvoja imunsko pogojenih neželenih učinkov, a je za razvoj takšnih modelov potrebno večje število podatkov, za kar so potrebne multicentrične klinične raziskave. 18 Ključne besede: imunoterapija, neželeni učinki, kvantifikacija, FDG-PET/CT, napovedovanje neželenih učinkov, kvantitativni slikovni biološki označevalci
Keywords: metastatski melanom, imunoterapija, neželeni učinki
Published in DiRROS: 06.06.2024; Views: 356; Downloads: 156
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1564. Poročilo državnega programa obvladovanja raka za leto 2023Sonja Tomšič, Janez Žgajnar, Katarina Plantosar, Amela Duratović Konjević, Katarina Torkar, Branko Zakotnik, 2024, published professional conference contribution Keywords: obvladovanje raka, državni program, onkologija
Published in DiRROS: 06.06.2024; Views: 280; Downloads: 105
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1565. 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: 345; Downloads: 292
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1566. 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: 448; Downloads: 716
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1567. 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: 1431; Downloads: 202
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1568. 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: 326; Downloads: 159
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1569. 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: 355; Downloads: 118
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1570. 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: 499; Downloads: 112
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