51. Estimation of the corrosion properties for titanium dental alloys produced by SLMTadeja Kosec, Mirjam Bajt Leban, Maja Ovsenik, Matej Kurnik, Igor Kopač, 2022, original scientific article Abstract: Titanium alloys are known for their excellent biocompatible properties. The development of additive-manufacturing technologies has increased the interest in the use of Ti-6Al-4V, produced by selective laser melting (SLM) method, also in dentistry, i.e., prosthodontics and orthodontics. In the present paper, the effect of laser printing parameters in the selective laser melting (SLM) process on the porosity and corrosion behavior of Ti-6Al-4V dental alloy was metallographically and electrochemically studied. All the tests were performed in artificial saliva at 37 °C. Different forms of Ti-6Al-4V alloy were selected: a reference sample, i.e., pre-fabricated milling disc in wrought condition and four different 3D-printed samples made from Ti-6Al-4V powder using the SLM method, one being heat treated. Electrochemical, spectroscopic and hardness measurements were employed in the study. It was shown that the SLM-produced Ti-6Al-4V samples with different printing parameters have similar microstructural and electrochemical properties, while the electrochemical properties of a reference and thermally treated 3D-printed sample were different, most probably due to the change in the microstructure of the alloys. The corrosion properties were related to the microstructural properties as well as to the pore density.
Keywords: Ti-6Al-4V, dental alloys, artificial saliva, selective laser melting, corrosion
Published in DiRROS: 31.05.2023; Views: 255; Downloads: 114
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52. Differences between 3-D printed and traditionally milled CoCr dental alloy from casted block in oral environmentMirjam Bajt Leban, Matej Kurnik, Igor Kopač, Matic Klug Jovičević, Bojan Podgornik, Tadeja Kosec, 2023, original scientific article Abstract: The aim of this study was to compare corrosion resistance and ion release in CoCr dental alloys with identical chemical compositions produced using different technologies (SLM – selective laser melting and milling from cast blocks) and heat treatment (SLM parts only). The corrosion properties were tested in artificial saliva, artificial saliva with fluoride ions, and artificial saliva with added lactic acid to simulate inflammations. The study included electrochemical tests, microstructural investigation and ion release tests in the three different environments for a total of 42 days. The best performance of CoCr as a result of potentiodynamic polarization was observed in the artificial saliva with added lactic acid, which is in contradiction with the highest ion release measured from all the materials tested and electrochemical impedance spectroscopy that showed a deterioration of the passive layer in an acidic environment. Microstructural investigation revealed that different phases precipitated by heat treatment trigger increased release of Mo and W ions. The printing method does not raise critically ion release from CoCr alloy, while the state of the surface greatly impacts the extent of the ion release. This study demonstrates the importance of an interdisciplinary approach to the study of corrosion and biocompatibility in dental alloys.
Keywords: CoCr dental alloy, selective laser melting, corrosion, ion release, artificial saliva
Published in DiRROS: 29.05.2023; Views: 340; Downloads: 288
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54. Značilnosti rastlinstva, živalstva in gozdnih sestojev v povodju Liščaka v južnih Julijskih AlpahPeter Razpet, Karin Rutar, Erik Kragelj, Igor Dakskobler, 2023, original scientific article Abstract: Članek vsebuje opis značilnosti rastlinstva in živalstva odmaknjene, le po stezah dostopne in skoraj povsem gozdnate grape v zahodni Sloveniji. Raznolikost gozdnih združb in sestojev je povezana z naravnimi značilnostmi, karbonatno-silikatno geološko podlago in velikimi strminami, a tudi s pozno poselitvijo in popolnim izumrtjem zaselkov pred petdesetimi leti in več. Bukovi sestoji, ki so jih nekoč zelo sekali, se že dolgo razvijajo po naravnih zakonitostih, nanje koreniteje vplivajo predvsem vetrolomi in žled. Pionirska grmišča in gozdovi so raznoliki po zgradbi in vrstni sestavi. V bližini nekdanjih bivališč so mogočna stara drevesa, gorski bresti, veliki jeseni in smreke, na nekdanjih njivah nastaja orehov gozd. Grapa je naravna vrednota; predlagamo, naj bi bilo celotno njeno povodje.
Keywords: rastlinstvo, živalstvo, drugotna sukcesija, gozdna krajina, Baška dolina, Slovenija
Published in DiRROS: 19.05.2023; Views: 353; Downloads: 99
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55. Mechanical performance of timber connections made of thick flexible polyurethane adhesivesJaka Gašper Pečnik, Igor Gavrić, Václav Sebera, Meta Kržan, Arkadiusz Kwiecień, BogusŁaw Zając, Boris Azinović, 2021, original scientific article Abstract: This study investigates timber connections with flexible polyurethane adhesives, which prove to have the po-tential for timber-adhesive composite structures without mechanical connections for seismic regions. Results of conducted cyclic double lap-shear adhesive timber joints tests were compared with available experimental re-sults on timber connections with standard mechanical dowel-type fasteners and with results of numerical finite element analysis. The study found that the shear strength, elastic stiffness and strength degradation capacity of the flexible adhesive connections were significantly higher compared to mechanical fasteners commonly used in seismic-resistant timber connections. The latter, however, manifested larger ultimate displacements but also yielded at lower displacements.
Keywords: flexible adhesive, timber connection, polyurethane, double lap-shear, cyclic loading, energy dissipation, open access
Published in DiRROS: 19.05.2023; Views: 385; Downloads: 249
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58. Comparison of the corrosion properties of CoCrMo dental alloys in artificial salivaTadeja Kosec, Mirjam Bajt Leban, Matej Kurnik, Igor Kopač, 2021, original scientific article Abstract: CoCrMo alloys are known for their biocompatible properties, which, together with their favorable mechanical properties, mean they can be efficiently used in dentistry. With the development of selective laser melting for the fabrication of 3D-printed ob - jects, interest in the corrosion properties of this alloy has risen in the field of prosthodontics. In the study, CoCrMoW dental al - loys were studied in artificial saliva at body temperature, i.e., 37 °C. Different forms of CoCrMoW alloy were selected: a refer - ence sample, i.e., original material as received from the supplier, a cast sample acquired from an ordinary procedure in a dental laboratory, and two 3D-printed samples made from CoCrMoW powder using the selective laser melting (SLM) method. Electro - chemical, spectroscopic and hardness measurements were conducted. It was shown that the reference and cast samples have similar microstructural and electrochemical properties, while the electrochemical properties of the 3D-printed samples differ, most probably due to the effect of the higher micro porosity and chemical composition of the alloys.
Keywords: CoCrMo dentalne zlitine, umetna slina, aditivne tehnologije, precizijsko ulivanje, korozija
Published in DiRROS: 02.12.2022; Views: 254; Downloads: 104
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59. Epidemiology and risk factors of self-reported systemic allergic reactions to a Hymenoptera venom in beekeepers worldwide : a protocol for a systematic review of observational studiesTanja Carli, Igor Locatelli, Mitja Košnik, Andreja Kukec, 2022, review article Abstract: Introduction Systemic allergic reaction (SAR) to a Hymenoptera venom is a potentially life-threatening disorder. The rate of SAR between beekeepers in comparison with a healthy individual is different. The risk for an SAR is particularly high in beekeepers due to their persistent or seasonal exposure to the stinging Hymenoptera. We aim to provide a critical appraisal and a synthesis of evidence-based data from epidemiological observational studies, focusing on SARs to a Hymenoptera venom and the associated risk factors for SARs in beekeepers worldwide. Methods and analysis Searching will include seven electronic databases for published studies without language restrictions, from inception up to 3 August 2021, and it will be rerun for all electronic databases prior publication. Only epidemiological observational studies in beekeepers will be included. The risk of bias in the included studies will be appraised by using the Joanna Briggs Institute Critical Appraisal Checklist for Analytical Cross-Sectional Studies and the Newcastle-Ottawa Scale, adapted for cross-sectional studies. For the certainty of evidence, the Grading of Recommendations Assessment, Development and Evaluation approach will be used. Qualitative synthesis will be presented in a tabulated format with the selected characteristics across primary studies and the main outcome of interest. A meta-analysis is planned to be performed if there will be a sufficient number of homogeneous studies with complete data. The Preferred Reporting Items for Systematic Review and Meta-Analysis Protocols 2015 statement will guide the reporting of this systematic literature review. Ethics and dissemination No ethics approval is needed to conduct the systematic literature review since it will be solely based on the published literature. Findings will be disseminated through the relevant conferences, peer-review and open-access journals.
Keywords: systemic allergic reaction (SAR), Hymenoptera venom, systematic literature review
Published in DiRROS: 31.08.2022; Views: 652; Downloads: 300
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60. Gibanje teologije osvoboditve : geneza, razcvet in zatonIgor Jurekovič, 2020, original scientific article Abstract: Zametki latinskoameriške teologije osvoboditve kot družbenega gibanja sega-jo v 50. leta minulega stoletja. Gibanje je nato počasi rastlo do svojega vrhunca v začetku 70. let 20. stoletja. Sledeč relacijski sociologiji Pierra Bourdieuja, trdimo, da so formaciji gibanja botrovali tako objektivno-strukturni družbeni pogoji kakor tudi primerna percepcija družbenih akterjev. Med ključnimi družbenimi pogoji, na katere se osredotoča prispevek, so industrializacija latinske Amerike, institucionalna kriza latinskoameriške RKC, drugi vatikanski koncil, nastajajoča intelektualna neodvisnost celine ter izoblikovanje v Evropi in ZDA izobraženih teologov osvoboditve. Razcvetu gibanja v začetku 70. let je sledila odločna sprva notranja, nato pa tudi vatikanska konservativna restavracija, ki je v dobrem desetletju uspela uspešno zatreti gibanje teologije osvoboditve. Ob upoštevanju končne predstavitve zatona teologije osvoboditve se kot nastavek za nadaljnje raziskovanje ponudi priljubljenost binkoštnega protestantizma, gibanja, ki se opazno povečuje v zadnjih 30 letih, sočasno s pojavom neoliberalnih strukturnih reform na globalnem jugu.
Keywords: teologija osvoboditve, družbena gibanja, katoliška cerkev, Latinska Amerika, sociologija religije
Published in DiRROS: 28.03.2022; Views: 591; Downloads: 339
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