1931. Demonstration of evolution of hemispherical spondysclerosis by contrast enhanced Gd-DTPA magnetic resonance imagingVladimir Jevtič, Natalija Majcen, 2004, original scientific article Abstract: Izhodišča. Namen študije je bil ugotoviti vrednost slikovne magnetne resonance(MRI) s paramagnetnim kontrastnim sredstvom Gd-DTPA v prikazu napredovanja hemisferične spondiloskleroze (HSS). Bolniki in metode. Pri 18 bolnikih s kronično bolečino v križu in tipičnimi radiografskimi znaki HSS smoopravili Gd-DTPA MRI lumbalne hrbtenice. Primerjali smo morfološke spremembe in spremembe intenzitete signala z radiografskimi znaki HSS. Rezultati. Na podlagi MRI smo primere razdelili v tri skupine. V prvi skupini je bilo radiografsko področje osteoskleroze hipointenzivno na T1-poudarjenih spin-eho slikah, hiperintenzivno na T2-poudarjenih slikah in je kazalo difuznonabiranje paramagnetnega kontrastnega sredstva. Opisane spremembe so bile združljive s kostnim edemom in hiperemijo. V drugi skupini so bili robovivretenc na vseh slikovnih sekvencah hiperintenzivni, obdani s hipointenzivno cono in se v njih ni nabiralo kontrastno sredstvo. Opisano je izražalo kombinacijo maščevja in kostne skleroze. Pri preostalih bolnikih so MRI znaki predstavljali kombinacijo sprememb vidnih v prvi in drugi skupini. Zaključki. Gd-DTPA MRI kaže zapletene histološke spremembe v teku napredovanjaHSS. Spremljanje značilnih MRI znakov ima lahko klinični pomen prisledenju bolezni. Published in DiRROS: 07.02.2024; Views: 389; Downloads: 87
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1932. 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: 434; Downloads: 240
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1933. Grain size distribution of DP 600 steel using single-pass asymmetrical wedge testUrška Klančnik, Peter Fajfar, Jan Foder, Heinz Palkowski, Jaka Burja, Grega Klančnik, 2023, original scientific article Keywords: wedge test, hot-rolling, grain size distribution, dual-phase steel Published in DiRROS: 07.02.2024; Views: 424; Downloads: 175
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1934. Thermal fatigue degradation progress in SiMo ductile cast iron under oxidation conditionsMilan Terčelj, Jaka Burja, Goran Kugler, Primož Mrvar, 2023, original scientific article Keywords: metallurgical engineering, exhaust manifolds, cast irons, casting, microscopic characterization and microanalysis, thermal fatigue, material defect, microstructural control Published in DiRROS: 07.02.2024; Views: 456; Downloads: 272
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1935. An experimental study of liquid micro-jets produced with a gas dynamic virtual nozzle under the influence of an electric fieldBor Zupan, Gisel Esperanza Peña-Murillo, Rizwan Zahoor, Jurij Gregorc, Božidar Šarler, Juraj Knoška, Alfonso M. Gañán-Calvo, Henry N. Chapman, Saša Bajt, 2023, original scientific article Abstract: The results of an experimental study of micro-jets produced with a gas dynamic virtual nozzle (GDVN) under the influence of an electric field are provided and discussed for the first time. The experimental study is performed with a 50% volume mixture of water and ethanol, and nitrogen focusing gas. The liquid sample and gas Reynolds numbers range from 0.09–5.4 and 0–190, respectively. The external electrode was positioned 400–500 μm downstream of the nozzle tip and an effect of electric potential between the electrode and the sample liquid from 0–7 kV was investigated. The jetting parametric space is examined as a function of operating gas and liquid flow rates, outlet chamber pressure, and an external electric field. The experimentally observed jet diameter, length and velocity ranged from 1–25 μm, 50–500 μm and 0.5–10 m/s, respectively. The jetting shape snapshots were processed automatically using purposely developed computer vision software. The velocity of the jet was calculated from the measured jet diameter and the sample flow rate. It is found that micro-jets accelerate in the direction of the applied electric field in the downstream direction at a constant acceleration as opposed to the standard GDVNs. New jetting modes were observed, where either the focusing gas or the electric forces dominate, encouraging further theoretical and numerical studies towards optimized system design. The study shows the potential to unlock a new generation of low background sample delivery for serial diffraction measurements of weakly scattering objects. Keywords: micro jet, electric field, experimental study, flow focusing, Taylor cone, gas dynamic virtual nozzles Published in DiRROS: 07.02.2024; Views: 504; Downloads: 192
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1936. Metal artefacts and remains of armour from Kozlov Rob castle : metallurgical analyses as a tool for identification and interpretation of fragmentary archaeological findsJakob Kraner, Tomaž Lazar, Miha Mlinar, Jaka Burja, 2023, original scientific article Keywords: archaeology, castle, Kozlov Rob, Slovenia, armour, helmet, metallography Published in DiRROS: 07.02.2024; Views: 454; Downloads: 176
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1938. Study on dissolution of Ba-containing inoculant in ductile cast iron melt and nucleation of graphiteMarica Tonkovič-Prijanovič, Primož Mrvar, Jaka Burja, Črtomir Donik, Mitja Petrič, 2023, original scientific article Keywords: inoculant, inoculant dissolving, reaction zone, phase composition, graphite nucleation, ductile cast iron, barium inoculant Published in DiRROS: 07.02.2024; Views: 336; Downloads: 197
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1939. An outbreak of Verticillium dahliae on sycamore maple in a forest stand in SloveniaAna Brglez, Zina Devetak, Nikica Ogris, Sebastjan Radišek, Barbara Piškur, 2024, original scientific article Abstract: Verticillium dahliae Kleb., the causal agent of Verticillium wilts, is a devastating plant disease affecting many plant species. Fungus V. dahliae was detected in a partially artificially established Acer pseudoplatanus L. forest stand in central Slovenia. This finding incited further study about the risk of different sources of V. dahliae isolates for maples in forests and the pathogenicity of three V. dahliae isolates of different origins was tested on saplings of A. pseudoplatanus, A. platanoides L., and A. campestre L. The inoculated saplings exhibited disease symptoms, i.e., leaf necrosis and wilting. At the end of the pathogenicity test, typical xylem browning was visible on the cross-sections, and the pathogen was successfully re-isolated. The isolates showed significant differences in their pathogenicity to specific maple hosts, with the agricultural isolate (originated from bell pepper) being the most aggressive on all three maple species. The disease severity index (DSI) and relative area under the disease progress curve (rAUDPC), as well as the success of re-isolation, indicate that A. platanoides is the most susceptible to inoculation with V. dahliae. In addition, significant differences in sapling biomass were observed between treated and control plants. These results suggest that maples in forest stands are threatened by V. dahliae, and biosecurity measures should be considered and implemented in forest management to reduce the transmission and potential spread of the pathogen. Keywords: Verticillium wilt, Acer spp., pathogenicity test, Disease severity index, DSI, Area under the disease progress curve, AUDPC, biosecurity Published in DiRROS: 07.02.2024; Views: 499; Downloads: 477
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1940. Small cellular particles from European spruce needle homogenateMarko Jeran, Anna Romolo, Vesna Spasovski, Matej Hočevar, Urban Novak, Roman Štukelj, Vid Šuštar, Matic Kisovec, Apolonija Bedina Zavec, Ksenija Kogej, Aleš Iglič, Polonca Trebše, Veronika Kralj-Iglič, 2023, original scientific article Keywords: Picea abies, spruce needles, extracellular particles, extracellular vesicles, small cellular particles, interferometric light microscopy, exosomes, cell-to-cell communication, drug delivery Published in DiRROS: 07.02.2024; Views: 390; Downloads: 220
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