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12. Understanding carbide evolution and surface chemistry during deep cryogenic treatment in high-alloyed ferrous alloyPatricia Jovičević Klug, Levi Tegg, Matic Klug Jovičević, Rahul Parmar, Matteo Amati, Luca Gregoratti, László Almásy, Julie M. Cairney, Bojan Podgornik, 2023, original scientific article Keywords: cryogenic temperature, surface chemistry, microstructure, atom probe tomography (APT), scanning photoelectron microscopy (SPEM), small angle neutron scattering (SANS)
Published in DiRROS: 08.03.2024; Views: 97; Downloads: 93
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13. Ecotoxicologically relevant cyclic peptides from cyanobacterial bloom (Planktothrix rubecens) - a threat to human and environmental healthBojan Sedmak, Tina Eleršek, Olga Grach-Pogrebinsky, Shmuel Carmeli, Nataša Sever, Tamara Lah Turnšek, 2008, original scientific article Abstract: Background. The information of the overall production of major cyanobacterial cyclic peptides in a water body is essential for risk assessment and for the prediction of future development of the bloom. A procedure that gives a reviewof both toxic and non-hepatotoxic hydrophilic cyclic peptide production is important to evaluate the ecological conditions in the water environment and to predict the release of dangerous toxic and tumour promoting substances.Methods. The cyclic peptides were identified on the basis of their retention times, characteristic spectra, molecular masses and biological activity. The non-hepatotoxic cyclic peptides were characterised by their inhibition of porcine pancreatic elastase, while cytotoxicity to mammalian cells was tested with the MTT test on B16 cell line. Conclusions. The method presented gives a rapid, simultaneous assessment, preliminary identification and estimation of bioactive cyclic peptides. The synthesis of non-hepatotoxic cyclic peptides can mediate the release various toxic and otherwise biologically active substances that induce systemic genotoxicity in mammals.
Keywords: tumor promoters, microcystin, anabaenopeptin, planktopeptin, toxic cyanobacterial blooms, environmental health
Published in DiRROS: 07.03.2024; Views: 123; Downloads: 24
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14. Subchronic exposure of rats to sublethal dose of microcystin-YR induces DNA damage in multiple organsMetka Filipič, Bojana Žegura, Bojan Sedmak, Irena Horvat-Žnidaršič, Aleksandra Milutinović Živin, Dušan Šuput, 2007, original scientific article Abstract: Background. Microcystins (MCs) are cyclic heptapeptides that are considered tobe liver specific toxins. They are potent tumour promoters and recent studies indicate that they are also genotoxic. In this study we measured DNA damage in lymphocytes, liver, kidney (cortex and medulla), lung, spleen and brain cells of male Fisher F344 rats that were exposed to sublethal dose (every second day 10 Ugžkg b.w.č i.p) of microeysrin-YR (MCYR) for one month. Methods. At the end of exposure the animals were sacrificed, the lymphocytes were isolated from blood taken from jugular vein, liver cells were obtained byperfusion with collagenase A and the cells from other organs were isolated by incubating small tissue pieces with eollagenase A. The DNA damage in isolated cells was measured with the single cells gel electrophoresis (SCGE) also called the comet assay. Results. A significant increase of the % tail DNAin MCYR-exposed animals compared to the nonexposed control ones was observed in brain (2.5 fold), liver (2.1 fold), kidney medulla (1.9 fold), kidney cortex (1.8 fold) and lung (1.7 fold) cells, while the DNA from lymphocytes and spleen cells was not affected. Conclusion. This study demonstrated that subehronic exposure to sublethal doses of MCs can induce systemicgenotoxicity in mammals, and it affects not only the liver but also other vital organs.
Keywords: DNA damage, comet assay, cyanobacteria, bacterial toxins, rats, inbred F344
Published in DiRROS: 20.02.2024; Views: 138; Downloads: 37
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15. Quasi-copulas as linear combinations of copulasGregor Dolinar, Bojan Kuzma, Nik Stopar, 2024, original scientific article Abstract: We prove that every quasi-copula can be written as a uniformly converging infinite sum of multiples of copulas. Furthermore, we characterize those quasi-copulas which can be written as a finite sum of multiples of copulas, i.e., that are a linear combination of two copulas. This generalizes a recent result of Fernández-Sánchez, Quesada-Molina, and Úbeda-Flores who considered linear combinations of discrete copulas.
Keywords: quasi-copulas, copulas, linear combination, affine combination, Minkowski norm
Published in DiRROS: 16.02.2024; Views: 154; Downloads: 64
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16. Early postoperative serum carcinoembryonic antigen levels in patients operated for colorectal carcinoma - a new method for following-upBojan Veingerl, 2003, professional article Abstract: Background. The only method of treatment offering a favourable prognosis for colorectal carcinoma is radical resection of the part of the colon or rectum including the pertaining lymph nodes and eventual radical removal of metastases. But even such presumably curative surgery does not warrant full recovery of all operated patients as recurrences are frequent and according tomost analyses 5-year survival is lower than 50%. Therefore, additional treatment is attempted in some patients. Various prognostic factor of disease recurrance are helful. One such prognostic sign is serum carcinoembryonic antigen (CEA) level measured soon after surgery. Conclusions. All patients with radical R0 resection, according to their postoperative serum CEA levels and the CEA half-life fall into three groups: CEA R0, CEA R1, and CEA R2 resected patients. A statistically significant difference regarding survival and number of recurrence was noted among patients categorized bz the stage of disease, particularly between the three groups of patients and the group having been undergone presumably curative surgery.
Published in DiRROS: 06.02.2024; Views: 139; Downloads: 24
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17. Austenite reversion suppression with deep cryogenic treatment : a novel pathway towards 3rd generation advanced high-strength steelsPatricia Jovičević Klug, Matic Klug Jovičević, Lars Thormählen, Jeffrey McCord, Michael Rohwerder, Matjaž Godec, Bojan Podgornik, 2023, original scientific article Keywords: Martensitic stainless steel, deep cryogenic treatment, microstructure, mechanical properties, microstructural transformations, phase transformation
Published in DiRROS: 02.02.2024; Views: 154; Downloads: 83
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19. Complex interdependency of microstructure, mechanical properties, fatigue resistance, and residual stress of austenitic stainless steels AISI 304LPatricia Jovičević Klug, Matic Klug Jovičević, Michael Rohwerder, Matjaž Godec, Bojan Podgornik, 2023, original scientific article Keywords: stainless steel, AISI 304L, deep cryogenic treatment (DCT), microstructure, mechanical properties, fatigue, residual stress
Published in DiRROS: 02.02.2024; Views: 169; Downloads: 83
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20. Tribological evaluation of vegetable ▫$oil/MoS_2$▫ nanotube-based lubrication of laser-textured stainless steelMarjetka Conradi, Bojan Podgornik, Maja Remškar, Damjan Klobčar, Aleksandra Kocijan, 2023, original scientific article Abstract: In the present work, the functionalisation of austenitic stainless steel, AISI 316L surfaces via nanosecond Nd:YAG laser texturing in order to modify the surface morphology with crosshatch and dimple patterns is presented. A tribological analysis under lubrication with sunflower and jojoba oil with and without the addition of a solid lubricant, MoS2 nanotubes, was performed. In conjunction with friction/wear response laser-textured surface wettability, oil spreadability and oil retention capacity were also analysed. It was shown that the crosshatch pattern generally exhibited lower friction than the dimple pattern, with the addition of MoS2 nanotubes not having any significant effect on the coefficient of friction under the investigated contact conditions. This was found in addition to the better oil spreadability and oil retention capacity results of the crosshatch-textured surface. Furthermore, texturing reduced the wear of the stainless-steel surfaces but led to an approximately one order of magnitude larger wear rate of the steel counter-body, primarily due to the presence of hard bulges around the textured patterns. Overall, the crosshatch pattern showed better oil retention capacity and lower friction in combination with different vegetable oils, thus making it a promising choice for improving tribological performance in various environmentally friendly applications.
Keywords: tribology, stainless steel, vegetable oil lubrication, MoS2 nanotubes
Published in DiRROS: 02.02.2024; Views: 130; Downloads: 75
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