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31.
Tribocorrosive study of new and in vivo exposed nickel titanium and stainless steel orthodontic archwires
Tadeja Kosec, Petra Močnik, Uroš Mezeg, Andraž Legat, Maja Ovsenik, Monika Jenko, John T. Grant, Jasmina Primožič, 2020, original scientific article

Abstract: The surface, corrosion and wear properties of new and in vivo exposed nickel titanium (NiTi) and stainless steel (SS) archwires used in orthodontic treatment were investigated. Electrochemical and tribo-electrochemical tests in artificial saliva were performed in order to define corrosion properties and to estimate wear rate of new and in vivo exposed NiTi and SS archwires. The surface chemical analysis of the passive film on the NiTi and SS archwires before and after tribocorrosion tests was performed by Auger Electron Spectroscopy (AES). In vivo exposed NiTi and SS archwires had better electrochemical properties than new archwires due to the protective nature of oral deposits. Total wear and coefficients of friction were higher among in vivo exposed archwires and higher in NiTi archwires in comparison to SS archwires. The estimated thickness of the TiO2 passive film on as-received NiTi is 8 nm, while the passive Cr2O3 film on as-received SS is just 1–2 nm. On in vivo exposed NiTi archwire, a 60–80 nm thick organic film/dental plaque was observed, and on SS, it was thinner, at about 60 nm. This research shows the importance of combining AES with electrochemical testing, to characterize tribocorrosive properties of NiTi and SS orthodontic archwires.
Keywords: archwires, NiTi, stainless steel, wear
Published in DiRROS: 24.08.2023; Views: 244; Downloads: 100
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32.
Effect of the microstructural properties of copper on corrosion performance
Tadeja Kosec, Jure Voglar, Petra Močnik, Andraž Legat, 2021, original scientific article

Abstract: The aim of the study was to define the influence of microstructural properties on the electrochemical properties of copper in four different forms: copper in sheet form, copper doped with phosphorus, electroplated copper and copper wire. Open circuit potential and polarization resistance measurements were carried out in order to determine the electrochemical properties and corrosion rates of copper in 0.1 M NaCl solution in oxic conditions at ambient temperature. Statistical evaluation of the electrochemical data was performed in order to differentiate between the various forms of copper samples. Microstructural and electrochemical investigations were combined with electron microscopy and Raman analysis of the corrosion products after immersion of the copper samples in a 0.1 M NaCl solution for 30 days. The various morphologies of copper corrosion products were identified and analyzed by Raman spectroscopy for the various forms of copper.
Keywords: copper, microstructura, corrosion, Raman
Published in DiRROS: 19.07.2023; Views: 271; Downloads: 129
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33.
Pitting corrosion on highly alloyed stainless steels in dilute sulphuric acid containing sodium chloride
Elina Huttunen-Saarivirta, Elisa Isotahdon, Zaiqing Que, M. Lindgren, Ahmad Mardoukhi, Jean-Baptiste Jorcin, Petra Močnik, Tadeja Kosec, Yassine El Ouazari, Sukanya Hägg Mameng, Lena Wegrelius, 2023, original scientific article

Abstract: Stainless steels are widely used in industrial assets and equipment. Despite their good corrosion resistance under a wide range of operating conditions, there is the possibility of pitting corrosion in the presence of chlorides. However, very few studies have identified the safe operating conditions for various high-alloyed stainless steel grades by comparing their pitting susceptibility. In this research, the susceptibility to pitting attack of five stainless steels with austenitic and duplex microstructures was examined in dilute sulphuric acid solution with varying amounts of NaCl at the temperatures of 50, 90 and 130◦C. Based on potentiodynamic polarization scans, none of the test materials underwent pitting corrosion at 50◦C, but differences in susceptibility to pitting attack were clear between the test materials and NaCl concentrations at the temperature of 90◦C, and further tem- perature increase facilitated uniform corrosion. 28-day immersion tests at 90◦ C confirmed the pitting suscepti- bility of duplex grades 1.4662 (PREN 33) and 1.4462 (PREN 35) in the presence of at least 2000 mg/L NaCl, but not the susceptibility of a corresponding austenitic grade 1.4539 (PREN 34). The grades 1.4547 (PREN 43) and 1.4410 (PREN 44) were not susceptible to pitting corrosion under any of the studied conditions. The results from materials microstructural and electrochemical characterization are presented and discussed in this paper.
Keywords: stainless steel, austenitic stainless steel, duplex stainless steel, pitting atttack
Published in DiRROS: 12.07.2023; Views: 282; Downloads: 339
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34.
Engineered combinatorial cell device for wound healing and bone regeneration
Lucija Kadunc, Duško Lainšček, Rok Gašperšič, Petra Sušjan, Uroš Kovačič, Miha Butinar, Boris Turk, Roman Jerala, Iva Hafner Bratkovič, 2023, original scientific article

Abstract: Growth factors are the key regulators that promote tissue regeneration and healing processes. While the effects of individual growth factors are well documented, a combination of multiple secreted growth factors underlies stem cell–mediated regeneration. To avoid the potential dangers and laborintensive individual approach of stem cell therapy while maintaining their regeneration-promoting effects based on multiple secreted growth factors, we engineered a “mix-and-match” combinatorial platform based on a library of cell lines producing growth factors. Treatment with a combination of growth factors secreted by engineered mammalian cells was more efficient than with individual growth factors or even stem cell–conditioned medium in a gap closure assay. Furthermore, we implemented in a mouse model a device for allogenic cell therapy for an in situ production of growth factors, where it improved cutaneous wound healing. Augmented bone regeneration was achieved on calvarial bone defects in rats treated with a cell device secreting IGF, FGF, PDGF, TGF-β, and VEGF. In both in vivo models, the systemic concentration of secreted factors was negligible, demonstrating the local effect of the regeneration device. Finally, we introduced a genetic switch that enables temporal control over combinations of trophic factors released at different stages of regeneration mimicking the maturation of natural wound healing to improve therapy and prevent scar formation.
Keywords: wound healing, bone regeneration, growth factors
Published in DiRROS: 01.06.2023; Views: 458; Downloads: 179
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35.
Seismic activity in the Celje Basin (Slovenia) in Roman times—archaeoseismological evidence from Celeia
Miklós Kázmér, Petra Jamšek Rupnik, Krzysztof Gaidzik, 2023, original scientific article

Abstract: Searching for unknown earthquakes in Slovenia in the first millennium, we performed archaeoseismological analysis of Roman settlements. The Mesto pod mestom museum in Celje exhibits a paved Roman road, which suffered severe deformation. Built on fine gravel and sand from the Savinja River, the road displays a bulge and trench, pop-up structures, and pavement slabs tilted up to 40°. The city wall was built over the deformed road in Late Roman times, supported by a foundation containing recycled material (spolia) from public buildings, including an emperor’s statue. We hypothesize that a severe earthquake hit the town before 350 AD, causing widespread destruction. Seismic-induced liquefaction caused differential subsidence, deforming the road. One of the nearby faults from the strike-slip Periadriatic fault system was the seismic source of this event.
Keywords: paleoseismology, Periadriatic fault system, active tectonics, Southern Alps, Pannonian Basin, Dinarides
Published in DiRROS: 14.02.2023; Views: 442; Downloads: 142
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Napovedna vrednost izraženosti androgenskega receptorja za razsoj v kosti pri trojno negativnem raku dojk
Petra Ilenič, Ajda Herman, Erik Langerholc, Barbara Gazić, Boštjan Šeruga, 2022, published professional conference contribution abstract

Keywords: onkologija, rak dojke, kemoterapija
Published in DiRROS: 27.01.2023; Views: 294; Downloads: 86
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Odprta znanost v programu Obzorje Evropa : Načrt ravnanja z raziskovalnimi podatki, 1. del
Tea Romih, Petra Durini, Brina Klemenčič, Uroš Kunaver, Miro Pušnik, 2022, professional film, videorecordings or sound recordings

Published in DiRROS: 19.01.2023; Views: 576; Downloads: 140
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