71. A method for the immobilization of chitosan onto urinary cathetersAlenka Vesel, Nina Recek, Rok Zaplotnik, Albert Kurinčič, Katja Kuzmič, Lidija Fras Zemljič, 2022, original scientific article Abstract: A method for the immobilization of an antibacterial chitosan coating to polymeric urinary medical catheters is presented. The method comprises a two-step plasma-treatment procedure, followed by the deposition of chitosan from the water solution. In the first plasma step, the urinary catheter is treated with vacuum-ultraviolet radiation to break bonds in the polymer surface film and create dangling bonds, which are occupied by hydrogen atoms. In the second plasma step, polymeric catheters are treated with atomic oxygen to form oxygen-containing surface functional groups acting as binding sites for chitosan. The presence of oxygen functional groups also causes a transformation of the hydrophobic polymer surface to hydrophilic, thus enabling uniform wetting and improved adsorption of the chitosan coating. The wettability was measured by the sessile-drop method, while the surface composition and structure were measured by X-ray photoelectron spectroscopy and Fourier-transform infrared spectroscopy. Non-treated samples did not exhibit successful chitosan immobilization. The effect of plasma treatment on immobilization was explained by noncovalent interactions such as electrostatic interactions and hydrogen bonds.
Keywords: polymer, chitosan immobilization, adhesion, plasma-surface modification, biopolymers
Published in DiRROS: 05.12.2022; Views: 566; Downloads: 321
 Full text (6,47 MB)
This document has many files! More... |
72. Priporočila za obravnavo bolnikov s pljučnim rakomMartina Vrankar, Nina Boc, Izidor Kern, Aleš Rozman, Karmen Stanič, Tomaž Štupnik, Mojca Unk, Maja Ebert Moltara, Vesna Zadnik, Katja Adamič, Jernej Benedik, Marko Bitenc, Jasna But-Hadžić, Anton Crnjac, Eva Ćirić, Tanja Čufer, Goran Gačevski, Marta Globočnik Kukovica, Kristina Gornik-Kramberger, Maja Ivanetič Pantar, Staša Jelerčič, Veronika Kloboves-Prevodnik, Mile Kovačević, Luka Ležaič, Mateja Marc-Malovrh, Katja Mohorčič, Bogdan Vidmar, Dušanka Vidovič, Gregor Vlačić, Ana Lina Vodušek, Rok Zbačnik, Ivana Žagar, 2022, not set Keywords: elektronske knjige
Published in DiRROS: 24.11.2022; Views: 846; Downloads: 298
Full text (3,01 MB)
This document has many files! More... |
73. |
74. |
75. Solid carriers of potentially toxic elements and their fate in stream sediments in the area affected by iron ore mining and processingSaša Kos, Nina Zupančič, Mateja Gosar, Miloš Miler, 2022, original scientific article Abstract: The potential environmental impact of historical mining and ore processing on stream sediments and water was studied in a small siderite iron ore deposit with diverse sulfide mineral paragenesis. The main aim was to characterize solid carriers of potentially toxic elements (PTEs) in stream sediments and mine waste, to understand their fate in fluvial systems. General mineralogy (X-ray powder diffraction) and individual solid PTE carriers (scanning electron microscopy/energy dispersive spectroscopy) were correlated with the geochemical composition of stream sediments, mine waste, and stream waters (inductively coupled plasma mass spectrometry). Primary solid PTE carriers were pyrite, chalcopyrite, sphalerite, Hg-bearing sphalerite, galena, and siderite. Slightly alkaline and oxidizing conditions in stream water promoted the transformation of primary phases into secondary PTE carriers. Fe(Mn)-oxide/oxyhydroxides were major sinks for Pb, Zn, and As. Compared to background levels, Co (14.6 ± 2.1 mg/kg), Cu (30 ± 2.9 mg/kg), Ni (32.1 ± 2.9 mg/kg), Pb (64.5 ± 16.4 mg/kg), Zn (175.3 ± 22.5 mg/kg), As (81.1 ± 63.7 mg/kg), and Hg (2 ± 0.8 mg/kg) were elevated in mining area. Mine waste contained similar PTE carriers as stream sediments, but much higher PTE contents. Prevailingly low PTE concentrations in streams, with the exception of As (1.97 ± 2.4 µg/L) and Zn (4.5 ± 5.7 µg/L), indicate the stability of PTE carriers. Environmental effects were not significant, and additional monitoring is recommended.
Keywords: environmental mineralogy, environmental geochemistry, potentially toxic elements, stream sediments, solid phases, iron ore deposit, SEM/EDS
Published in DiRROS: 16.11.2022; Views: 668; Downloads: 193
Full text (8,07 MB) |
76. |
77. |
78. Priporočila za obravnavo bolnic z rakom jajčnikov, jajcevodov in s primarnim peritonealnim seroznim rakom v SlovenijiNina Kovačević, 2022, not set Keywords: serozni rak, diagnostika, sledenje pacientov, recidiv, epidemiologija, histopatologija, kirurško zdravljenje, sistemsko zdravljenje, radioterapija, gensko svetovanje, zdravstvena obravnava, smernice, zborniki
Published in DiRROS: 10.11.2022; Views: 702; Downloads: 191
Full text (397,45 KB) |
79. 3. šola o sarkomih : Mezenhimski tumorji maternice2022, not set Keywords: rak (medicina), multidisciplinarna obravnava, klasifikacija, diagnostika, patološka histologija, kirurško zdavljenje, biološko zdravljenje, sistemsko zdravljenje, radioterapija, sledenje pacientov, zborniki
Published in DiRROS: 09.11.2022; Views: 694; Downloads: 320
Full text (4,12 MB)
This document has many files! More... |
80. Effects of desiccation and freezing on microbial ionizing radiation survivability : considerations for Mars sample returnWilliam H. Horne, Tine Grebenc, Rok Tkavc, Cene Gostinčar, Nina Gunde-Cimerman, 2022, original scientific article Abstract: Increasingly, national space agencies are expanding their goals to include Mars exploration with sample return. To better protect Earth and its biosphere from potential extraterrestrial sources of contamination, as set forth in the Outer Space Treaty of 1967, international efforts to develop planetary protection measures strive to understand the danger of cross-contamination processes in Mars sample return missions. We aim to better understand the impact of the martian surface on microbial dormancy and survivability. Radiation resistance of microbes is a key parameter in considering survivability of microbes over geologic times on the frigid, arid surface of Mars that is bombarded by solar and galactic cosmic radiation. We tested the influence of desiccation and freezing on the ionizing radiation survival of six model microorganisms: vegetative cells of two bacteria (Deinococcus radiodurans, Escherichia coli) and a strain of budding yeast (Saccharomyces cerevisiae); and vegetative cells and endospores of three Bacillus bacteria (B. subtilis, B. megaterium, B. thuringiensis). Desiccation and freezing greatly increased radiation survival of vegetative polyploid microorganisms when applied separately, and when combined, desiccation and freezing increased radiation survival even more so. Thus, the radiation survival threshold of polyploid D. radiodurans cells can be extended from the already high value of 25 kGy in liquid culture to an astonishing 140 kGy when the cells are both desiccated and frozen. However, such synergistic radioprotective effects of desiccation and freezing were not observed in monogenomic or digenomic Bacillus cells and endospores, which are generally sterilized by 12 kGy. This difference is associated with a critical requirement for survivability under radiation, that is, repair of genome damage caused by radiation. Deinococcus radiodurans and S. cerevisiae accumulate similarly high levels of the Mn antioxidants that are required for extreme radiation resistance, as do endospores, though they greatly exceed spores in radioresistance because they contain multiple identical genome copies, which in D. radiodurans are joined by persistent Holliday junctions. We estimate ionizing radiation survival limits of polyploid DNA-based life-forms to be hundreds of millions of years of background radiation while buried in the martian subsurface. Our findings imply that forward contamination of Mars will essentially be permanent, and backward contamination is a possibility if life ever existed on Mars.
Keywords: ionizing radiation, life on Mars, astrobiology, radiation, fungi, bacteria, radiotolerance
Published in DiRROS: 03.11.2022; Views: 684; Downloads: 326
Full text (922,44 KB)
This document has many files! More... |
