11. Small-bowel carcinoid presenting with acute bleeding detected upon wireless capsule endoscopyŽiva Mrevlje, Marko Sever, Borut Kocijančič, 2005, izvirni znanstveni članek Povzetek: Background. Intestine carcinoid usually presents with clinical symptoms and signs deriving from its endocrinological influences and rarely bleeds profusely. Case report. We present a patient with intestinal bleeding of unknown origin. After conventional diagnostic procedures only wireless capsuleendosopy was able to discover a tumour of small bowel, which was the reason of bleeding. On patohistological examination after the surgical resection it proved to be a small bowel carcinoid. Conclusions. There are indications that WCE, besides being the first small bowel imaging technique, is a very important diagnostic tool, deserving consideration in the early phases of diagnosing small-bowel disease, especially in less intensive or occult bleeding.
Objavljeno v DiRROS: 14.02.2024; Ogledov: 135; Prenosov: 24
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12. Setup and its effect on safety margin in conformal radiotherapy of the prostateBorut Kragelj, 2005, izvirni znanstveni članek Povzetek: Background. In radiotherapy, setup errors in positioning the patients influence the size of safety margin and thereby also the size of irradiation field and toxicity of radiotherapy. Methods. The setup errors were calculated by evaluating the deviations from the measured distance between the irradiation field margin and the bony pelvis. Results. The research was performed on 23 patients. With respect to lateral, craniocaudal and anteroposterior axis, the observed systemic error ranged from -5 to + 9 mm, -4to +5 mm, and from -4 to +4 mm, respectively, whereas the observed random error ranged from 0 to 7.5 mm, 0 to 3.6 mm, and from 0 to 4.2 mm, respectively. The safety margin, with the 90% probability to cover clinical target volume (CTV) and allowing for the prostate position variability, measured 9 mm, 9.5 mm, 7 mm, and 10 mm in the respective lateral, craniocaudal, anterior and dorsal direction. Conclusions. Irradiation of the prostate with a 7 mm dorsal safety margin, allowing for 90% coverage probability of CTV, was feasible in 22/23 patients on condition that the grosssystemic error (>3mm) was eliminated.
Objavljeno v DiRROS: 14.02.2024; Ogledov: 140; Prenosov: 33
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13. 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, izvirni znanstveni članek Povzetek: 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.
Ključne besede: total hip arthroplasty, modular neck, Ti6Al4V alloy, CoCrMo alloy, corrosion
Objavljeno v DiRROS: 07.02.2024; Ogledov: 229; Prenosov: 126
Celotno besedilo (5,12 MB)
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14. The urokinase plasminogen activator and its inhibitors PAI-1 nad PAI-2 in primary cutaneous melanomaJasmina Markovič Božič, Borut Štabuc, 2003, izvirni znanstveni članek Povzetek: Background. We investigated the differences in urokinase plasminogen activator(uPA) and its inhibitors type-1 and 2 (PAI-1/2) concentrations in clinically suspected nevi, primary cutaneous melanoma and normal skin and correlations with histopathological prognostic factors of primary melanoma. Patients and methods. Fifty-one patients were enrolled. The tissue concentrations of uPA, PAI 1 and PAI2 were quantified by enzyme-linked immunosorbent assay (ELISA). Results. Mean uPA and PAI-1 concentrations in melanomas were higher than in normal surrounding skin (uPA: 1.08; vs. 0.48 ng/mgp; PAI-1: 14.07 vs. 2.07 ng/mgp; p < 0.001), uPA and PAI-1 concentrationswere higher in melanomas than in nevi, and higher in nevi than in normal surrounding skin (uPA: p > 0.05; PAI-1: p = 0.02). PAI-2 concentration was higher in normal surrounding skin than in nevi and melanomas(p > 0.05). Melanoma uPA, PAI-1 and PAI-2 concentrations correlated significantly with normal skin (r= 0.73, 0.54, 0.38 respectively). PAI 1 was significantly lower in melanomas of Breslow thickness < 0.75 mm, Clark invasion of O+I, without microscopic ulceration, without vascular invasion (p < 0.01) than in melanomas of Breslow thickness > 0.75 mm, Clark invasion > II,with ulceration and vascular invasion. Conclusions. Determination of uPA and PAI-1 can provide significant additional prognostic information for melanoma patients.
Objavljeno v DiRROS: 06.02.2024; Ogledov: 123; Prenosov: 29
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16. Influence of precipitation hardening on the mechanical properties of Co-Cr-Mo and Co-Cr-W-Mo dental alloysMarko Sedlaček, Katja Zupančič, Barbara Šetina, Borut Kosec, Matija Zorc, Aleš Nagode, 2023, izvirni znanstveni članek Ključne besede: Co-Cr alloys, microstructure analysis, hardness, wear resistance
Objavljeno v DiRROS: 01.02.2024; Ogledov: 191; Prenosov: 118
Celotno besedilo (53,05 MB)
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17. High-temperature oxidation of boiler steels at 650 °CJaka Burja, Barbara Šetina, Borut Žužek, Tilen Balaško, 2023, izvirni znanstveni članek Povzetek: This study presents a comprehensive investigation of the formation, composition and
behaviour of oxide layers during the high-temperature oxidation of four different steel alloys (16Mo3,
13Cr, T24 and P91) at a uniform temperature of 650 °C. The study is aimed at assessing the oxidation
damage due to short-term overheating. The research combines CALPHAD (CALculation of PHAse
Diagrams) calculations, thermogravimetric analysis (TGA) and advanced microscopy techniques, in-
cluding scanning electron microscopy (SEM) and electron backscatter diffraction (EBSD), to elucidate
the complex mechanisms controlling oxidation kinetics and oxide layer development. CALPHAD
calculations were used to determine the thermodynamically stable phases for each steel type at 650
◦C and different oxygen activities. The results showed different phase compositions, highlighting
the importance of the chromium content in steel for the formation of oxide layers. The different
oxidation kinetics and oxide layer compositions are presented and associated with the increased risk
of material degradation due to overheating. These results have significant implications for industrial
applications, mainly the susceptibility to oxidation of low-alloyed steels like 16Mo3 and 13 Cr and
contribute to a deeper understanding of oxidation processes in steels.
Ključne besede: high-temperature oxidation, thermogravimetric analysis, kinetics, CALPHAD, boiler steels, SEM, EBSD
Objavljeno v DiRROS: 26.01.2024; Ogledov: 231; Prenosov: 111
Celotno besedilo (12,99 MB)
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18. Radical irradiation of the prostate. Combination of percutaneous irradiation and irradiation with LDR Ir-192 implantsBorut Kragelj, Franc Guna, Janez Burger, 2001, izvirni znanstveni članek Povzetek: Background. The irradiation of the carcinomas of the prostate with the doses above the tolerable ones of standard radiotherapy improves the local control of the disease. The aim of this study is to determine the acute toxicity and tolerability of the high-dose prostate irradiation combining external beam radiotherapy (EBRT) and interstitial low dose rate (LDR) brachyradiotherapy (BRT) Ir-192 of the prostate. Material and methods. We examined medical records of 8 patients with localized carcinoma of the prostate (T2-T3 No-x Mo)treated from August 1999 until February 2000. The initial PSA was 2.7-37.5 ng/ml (median 13.7) and Gleason score 4-9 (median 7). Radiotherapy consisted of 48.6-50.4 Gy of EBRT to the prostate and seminal vesicles (4 patients) or the whole pelvis (4 patients) and 20.0-28.0 Gy of interstital LDR Ir-192 BRT given as a single fraction, fluoroscopic guided transperineal Implantation of the prostate. The cumulative doses of percutaneous and interstitial irraditations to the prostate were 68.6 - 79.1 Gy. Results. Acute toxic effects of irradiation though observed in all patients were of only mild intensity. According to the RTOG criteria, 20/30 toxicities were assessed as grade 1, 9/30 as grade 2, and 1/30 as grade 3. In none of the patients, toxic effects required any specific modification of the treatment regimen. Conclusions. The very first experiences indicate moderate toxicity and optimaltolerance of the treatment by patients. An improvement of implantation techniques may be expected with regular CT controls of the implants and extra attentive care of the implants in the urethra region.
Objavljeno v DiRROS: 25.01.2024; Ogledov: 162; Prenosov: 40
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