1. |
2. 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: 73; Downloads: 63
 Full text (8,47 MB)
This document has many files! More... |
3. Sinonasal inverted papilloma associated with squamous cell carcinomaJasna But-Hadžić, Klemen Jenko, Mario Poljak, Boštjan Kocjan, Nina Gale, Primož Strojan, 2011, original scientific article Keywords: rak (medicina), papiloma virusi, nosna votlina, karcinom, zdravljenje, radioterapija
Published in DiRROS: 18.03.2024; Views: 181; Downloads: 46
Full text (513,64 KB) |
4. Development of the recycling procedure for rapid antigen testsRebeka Rudolf, Darja Feizpour, Žiga Jelen, Peter Majerič, Tilen Švarc, Matej Zadravec, Timi Gomboc, Aleksandra Kocijan, 2024, original scientific article Keywords: rapid antigen tests, recycling, characterization, nanogold, plastic
Published in DiRROS: 28.02.2024; Views: 248; Downloads: 91
Full text (1,74 MB)
This document has many files! More... |
5. Stereotaktična radioterapija za zdravljenje refraktarne prekatne tahikardije: prikaz primerovTamara Jarm, Krištof Knap, Bor Antolič, Boštjan Berlot, Rihard Hudej, Aljaša Jenko, Ajra Šečerov Ermenc, Jasna But-Hadžić, Ivica Ratoša, 2023, professional article Abstract: Stereotaktična radioterapija aritmij (STAR) predstavlja novo in obetavno možnost za bolnike z refraktarno prekatno tahikardijo, ki je odporna proti konvencionalnim metodam zdravljenja. STAR omogoča natančno neinvazivno ablacijo aritmogenega substrata ob minimalni prizadetosti sosednjih organov. Ta metoda zdravljenja je uporabna za bolnike, pri katerih je tarčno tkivo s katetrsko ablacijo nedosegljivo, pogosti šoki implantabilnega kardioverter-defibrilatorja pa močno nižajo njihovo kakovost življenja ali kadar sta ti metodi zdravljenja zaradi slabega zdravstvenega stanja kontraindicirani. Tarčo obsevanja (predel levega prekata) natančno opredelimo s predhodno slikovno diagnostiko, elektrokardiogramom, posnetki prekatne tahikardije in po potrebi invazivnim ali neinvazivnim elektrofiziološkim mapiranjem srca. Po pripravi na obsevanje na simulatorju sledi enkratno obsevanje z visokim odmerkom 25 Gy, ki je trenutno edina standardna frakcionacija. Bolniki obsevanje dobro prenašajo. Dosedanje raziskave so poročale o dobri učinkovitosti zdravljenja z bistvenim zmanjšanjem pogostosti epizod prekatne tahikardije in brez večjih neželenih učinkov. Poročamo o prvi skupini štirih bolnikov z visokorizično refraktarno prekatno tahikardijo, ki so bili zdravljeni s stereotaktično radioterapijo na Onkološkem inštitutu Ljubljana. Izvedba STAR se je izkazala kot učinkovita metoda z nizko stopnjo akutnih neželenih učinkov in predstavlja novo možnost obravnave te ranljive skupine bolnikov v slovenskem prostoru.
Keywords: stereotaktična radioterapija, aritmije, prekatna tahikardija, radioablacija srca
Published in DiRROS: 26.02.2024; Views: 194; Downloads: 51
Full text (146,07 KB) |
6. Mechanisms of premature fracture in modular neck stems made of CoCrMo/Ti6Al4V and Ti6Al4V/Ti6Al4V alloyDrago Dolinar, Miro Gorenšek, Klemen Avsec, Barbara Šetina, Matej Hočevar, Matjaž Godec, Borut Žužek, Mojca Debeljak, Monika Jenko, John T. Grant, Boštjan Kocjančič, 2023, original scientific article Abstract: In this paper, we present the mechanisms of premature fracture of modular neck stems in two case studies: (I) when the neck and stem are both made of the same Ti6Al4V alloy, and (II) when the neck and stem are made from two different alloys, CoCrMo and Ti6Al4V alloy. Our study integrates two orthopedic patients who have undergone primary uncemented THA for usual indications in two orthopedic centers (Community Health Centre and University Medical Centre). Both centers are part of the national public health care system. Both surgeries were performed by two skilled orthopedic surgeons with more than 10 years of experience in THA. The survivorship of the modular neck of cast CoCrMo alloy was 24 months. The survivorship of the modular neck from Ti6Al4V alloy was 84 months. Multivariate analyses were performed to assess the differences in the fretting, corrosion, and fatigue of the two prematurely failed modular neck stems: stereo light microscopy (SLM), scanning electron microscopy (SEM), X-ray energy-dispersive spectroscopy (EDS), and electron backscatter diffraction (EBSD). Patient demographic information, including sex, age, body mass index, survivorship of implants, and reason for the revision, was collected from medical records. We found that fretting and fatigue occurred on both neck-stem retrievals due to additional galvanic corrosion, but the CoCrMo/Ti6Al4V alloy system suffered more corrosion due to additional galvanic corrosion and fractured earlier than the Ti6Al4V/Ti6Al4V metal alloy system. Both metallic alloy systems used in this application are known to be highly corrosion-resistant, but the bio-tribo-corrosion processes need to be understood in detail and characterized so that appropriate improvements in design and materials can be made.
Keywords: total hip arthroplasty, modular neck, Ti6Al4V alloy, CoCrMo alloy, corrosion
Published in DiRROS: 07.02.2024; Views: 305; Downloads: 156
Full text (5,12 MB)
This document has many files! More... |
7. Evaluation of the impact and fracture toughness of a nanostructured bainitic steel with low retained austenite contentMihael Brunčko, Peter Kirbiš, Ivan Anžel, Leo Gusel, Darja Feizpour, Tomaž Irgolič, Tomaž Vuherer, 2023, original scientific article Keywords: evaluation of fracture toughness, impact toughness, nanostructured bainite, natural aging, low retained austenite content, kinetically activated bainite KAB
Published in DiRROS: 02.02.2024; Views: 239; Downloads: 96
Full text (6,44 MB)
This document has many files! More... |
8. Inflammatory, oxidative stress and small cellular particle response in HUVEC induced by debris from endoprosthesis processingZala Jan, Matej Hočevar, Veno Kononenko, Sara Michelini, Neža Repar, Maja Caf, Boštjan Kocjančič, Drago Dolinar, Slavko Kralj, Darko Makovec, Aleš Iglič, Damjana Drobne, Monika Jenko, Veronika Kralj-Iglič, 2023, original scientific article Keywords: endoprosthesis failure, corundum, cytokines, reactive oxygen species, lipid droplets
Published in DiRROS: 02.02.2024; Views: 284; Downloads: 104
Full text (4,34 MB)
This document has many files! More... |
9. Recovery study of gold nanoparticle markers from lateral flow immunoassaysTilen Švarc, Peter Majerič, Darja Feizpour, Žiga Jelen, Matej Zadravec, Timi Gomboc, Rebeka Rudolf, 2023, original scientific article Abstract: Lateral flow immunoassays (LFIAs) are a simple diagnostic device used to detect targeted analytes. Wasted and unused rapid antigen lateral flow immunoassays represent mass waste that needs to be broken down and recycled into new material components. The aim of this study was to recover gold nanoparticles that are used as markers in lateral flow immunoassays. For this purpose, a dissolution process with aqua regia was utilised, where gold nanoparticles were released from the lateral flow immunoassay conjugate pads. The obtained solution was then concentrated further with gold chloride salt (HAuCl4) so that it could be used for the synthesis of new gold nanoparticles in the process of ultrasonic spray pyrolysis (USP). Various characterisation methods including scanning electron microscopy, transmission electron microscopy, ultraviolet-visible spectroscopy and optical emission spectrometry with inductively coupled plasma were used during this study. The results of this study showed that the recovery of gold nanoparticles from lateral flow immunoassays is possible, and the newly synthesised gold nanoparticles represent the possibility for incorporation into new products.
Keywords: gold nanoparticles, recovery, LFIA, ultrasonic spray pyrolysis, characterisation
Published in DiRROS: 02.02.2024; Views: 248; Downloads: 100
Full text (6,25 MB)
This document has many files! More... |
10. The impact of Al2O3 particles from grit-blasted Ti6Al7Nb (alloy) implant surfaces on biocompatibility, aseptic loosening, and infectionBoštjan Kocjančič, Klemen Avsec, Barbara Šetina, Darja Feizpour, Matjaž Godec, Veronika Kralj-Iglič, Rok Podlipec, Andrej Cör, Mojca Debeljak, John T. Grant, Monika Jenko, Drago Dolinar, 2023, original scientific article Keywords: Ti6Al7Nb implant alloy cementless hip endoprostheses, roughness, Al2O3 grit blasting, surface and subsurface implant contamination, cytotoxicity, aseptic loosening, infection, osseointegration
Published in DiRROS: 01.02.2024; Views: 265; Downloads: 92
Full text (16,21 MB)
This document has many files! More... |
