31. Corrosion protection of brown and green patinated bronzeTadeja Kosec, Živa Novak, Erika Švara Fabjan, Luka Škrlep, Andrijana Sever Škapin, Polonca Ropret, 2021, original scientific article Abstract: Bronze surfaces, whether bare or patinated, tend to change when exposed to an outdoor atmosphere. Art made of bronze which is exposed to the outdoors is usually artificially patinated. This patina changes when exposed to rain, especially in polluted rain, where sulphuric, nitric or carbonic acids are present.
In order to gain optimal protection of different patinas and consequently reduce the patina changes over the time different protection systems were developed, tested and tailored. Three types of patina (brown, green sulphate, and green persulphate) were prepared, protected and subsequently studied. The protections were based on two coatings (i) fluoropolymer based coating (FA-MS) and (ii) newly developed fluoropolymer based coating with addition of mercaptopropyl groups, named as alternative fluoropolymer coating (FA-MS-SH). Both the pure patinas applied on bronze surfaces as well as the bare bronze were electrochemically tested, first unprotected and then following the application of two different types of protection. After the protection was applied to the pa- tinas, the change in colour was defined. Different techniques were utilised in order to define the morphology and structure of the patinas, as well as the change in colour following application of the coating. It was shown that a fluoropolymer coating (FA-MS) provided the most efficient protection to bare bronze and the sulphate patina, while a newly proposed alternative fluoropolymer coating (FA-MS-SH) offered good protection to bare and brown patinated bronze. A mechanism for the protection of bare and patinated bronze was suggested.
Keywords: bronze, patina, protection
Published in DiRROS: 17.07.2023; Views: 329; Downloads: 186
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32. Exploring the protection mechanism of a combined fluoropolymer coating on sulphide patinated bronzeTadeja Kosec, Živa Novak, Erika Švara Fabjan, Luka Škrlep, Matjaž Finšgar, 2022, original scientific article Abstract: When bronze or artificially patinated bronze is exposed to an outdoor environment that contains aggressive ions such as sulphates, nitrates, and carbonates, the surface of the bronze changes its appearance due to the formation of corrosion products on the surface. Research is being conducted on versatile protective measures that can be used to protect the surface from these changes. A recently synthesised fluoropolymer-based coating with mercaptopropyl groups, i.e. a 3-component fluoropolymer coating FA-MS-SH (silane-modified poly methylmethacrylate (MS) with added mercaptopropyltrimethoxy silane (SH) and a fluoroacrylate (FA)) was explored in detail in this work where its protective mechanism on sulphide patinated bronze was investigated. Electrochemical tests were conducted on the sulphide patinated bronze with and without the 3-component coating FA-MS-SH. Furthermore, FA, MS and SH alone and various combinations and concentrations of FA-MS were studied in order to determine the protective effect and properties of each component. Colour change and contact angle measurements were also defined. FIB-SEM measurements and GCIB-XPS depth profiles were carried out to study surface bonding with the sulphide patina in detail.
A mechanism for the protection of sulphide patinated bronze was presented through the use of a multianalytical tool approach. It was shown that FA physisorbed on the patinated surface, while MS and blends of the components chemisorbed on the layer of sulphide patinated bronze, also resulting in the surface being efficiently protected from corrosion processes.
Keywords: bronze, protection, brown patina, fluoropolymer coating
Published in DiRROS: 31.05.2023; Views: 373; Downloads: 209
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33. Properties of the fluoroacrylate and methacryloxypropyl-trimethoxysilane applied to a layer of Cu2O on bronze as either single or multi-component coatingsLuka Škrlep, Tadeja Kosec, Matjaž Finšgar, Andrijana Sever Škapin, Erika Švara Fabjan, 2023, original scientific article Abstract: Various coatings have been developed and explored to protect bronze surfaces against the uncontrolled formation of different corrosion products when exposed to outdoor environments.
In this research, the surfaces of artificially-formed oxidized bronze patinas (OB), consisting of Cu2O, were covered with either a single-component (fluoroacrylate, FA or methacryloxypropyl-trimethoxysilane, MS) or multi-component (a mixture of FA and MS, FA-MS) fluoropolymer coating and investigated. Variations in the concentration of each component in the coating were studied. Electrochemical tests were performed to determine the corrosion protection efficiency, followed by detailed surface analyses of the OBs, both uncoated and covered with single and multi-component coatings. A variety of investigative methods were used, including focused ion beam scanning electron microscopy (FIB-SEM), X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM), and time-of-flight secondary ion mass spectrometry (ToF-SIMS).
The coating made from a combination of FA and MS resulted in a very high protection efficiency. Despite the increased hydrophilicity of the single MS component, however, it was shown to efficiently protect the oxidized bronze surface. The FA-MS systems showed high hydrophobicity, but no improvement was measured in the efficiency of the corrosion protection when it was compared to the coating that contained 10% MS. According to XPS and ToF-SIMS imaging, the FA component of the FA-MS coating was not present only on the uppermost surface of the coating but throughout the whole coating, which could affect its corrosion protection efficiency.
Keywords: bronze, Cu2O layer on bronze, fluoropolymer coating, protection efficiency, surface spectroscopy
Published in DiRROS: 30.05.2023; Views: 369; Downloads: 192
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34. The effects of large-scale forest disturbances on hydrology : an overview with special emphasis on karst aquifer systemsUrša Vilhar, Janez Kermavnar, Erika Kozamernik, Metka Petrič, Nataša Ravbar, 2022, original scientific article Abstract: Large-scale forest disturbances (LSFD) are an essential component of forest ecosystem dynamics. The effects of rapid loss of forest cover and other changes in forest ecosystems are inextricably linked to hydrologic processes such as evapotranspiration, soil and recharge processes. Among all hydrogeological systems, karst aquifers are important because of their exceptionally rich and unique biodiversity, biomass, and groundwater resources. At the same time, they are characterized by specific hydrological processes that make them highly vulnerable to environmental changes. Therefore, this study paid special attention to the effects of LSFD on karst hydrology. Using the PRISMA checklist, a thorough literature review of studies published between 2001 and 2020 was compiled into a comprehensive matrix dataset. In addition, an initial assessment of the global and regional distribution of forests on carbonate rocks was made based on publicly available geodatabases of forests and karst aquifers. The compiled information provides the first global overview of hydrological processes affected by LSFD, and identifies important knowledge gaps and future research challenges. The matrix dataset contained 117 full-text articles with a total of 160 case studies. Most publications were from 2011 to 2017, with more than half of the studies at the plot level and more than one-third at the catchment level. Studies on the effects of fires and pest and diseases infestations predominated. However, no articles were found on the effects of ice storms on hydrology in general or on the effects of pest and disease infestations on hydrology in karst areas. Of the 45.6 M km2 of forested land worldwide, 6.3 M km2 or 13.9% of all forests are underlain by carbonate rocks. Carbonate rocks cover about 15% of the land surface, which means that 31.3% of the world's karst aquifers are covered by forest. 29% of all case studies were conducted in karst areas, which is a high proportion compared to the proportion of forests in karst areas. However, these studies are unevenly distributed geographically. Most studies were conducted at the plot level, and only 21% of studies focused on natural LSFD, so forest management and land use change studies predominated. Although studies on the effects of LSFD on evapotranspiration processes between vegetation, air and soil are fairly well represented, infiltration and recharge processes in karst areas remain poorly understood and knowledge is lacking, particularly on groundwater flow and related hydrological processes. Regional studies and impacts on groundwater resources are also insufficient. The results indicate an urgent need for an integrated holistic interdisciplinary approach and a comprehensive understanding of the individual influencing factors, which would allow more accurate modelling of hydrological processes in forested karst aquifers.
Keywords: natural disasters, climatic changes, evapotranspiration, hydrology, karst aquifers
Published in DiRROS: 19.05.2023; Views: 406; Downloads: 224
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36. Vloga zaviralcev imunskih kontrolnih točk pri zdravljenju raka neznanega izvoraErika Matos, Kaja Cankar, 2023, published scientific conference contribution Abstract: Rak neznanega izvora (RNI) je histološko potrjen rak, pri keterem anatomski izvor kljub izčrpni diagnostiki ostane nerazpoznan. Trenutno nimamo dokazov, da bi identifikacija tkivnega izvora RNI in usmerjeno zdravljenje izboljšalo preživetje bolnikov, v primerjavi z empiričnim zdravljenjem, je pa pomembno, da v skupini bolnikov z RNI identificiramo in ustrezno zdravimo tiste bolnike, ki jih uvrščano v prognostično ugodno skupino. Zaviralci imunskih kontrolnih točk (ZIKT) so učinkovita zdravila za zdravljenje malignih bolezni različnega izvora. V literaturi najdemo anekdotične opise učinkovitosti te skupine zdravil tudi pri bolnikih z rakom neznanega izvora (RNI). Rezultati edine do sedaj zaključene raziskave, ki je usmerjeno proučevala ZIKT pri bolnikih z RNI, NivoCUP, faza 2, kažejo na potencialno učinkovitost nivolumaba pri bolnikih z RNI. Objektivni odgovor je bil dosežen pri 21,4% bolnikov, med njimi tudi tistih z verjetno kemo-rezistentnimi tumorji, pri nekaterih bolnikih so bili odgovori na zdravljenje dolgotrajni. Rezultati sicer potrebujejo potrditev z obsežnejšo, randomizirano raziskavo. Pembrolizumab je trenutno edini ZIKT, ki ima s strani ameriške regulatorne organizacije (FDA) odobritev za agnostično zdravljenje v primeru dokazane okvare proteinov za popravljanje neujemanja oz. visoke mikrosatelitne nestabilnosti (MSI-H/MMRd) ali visokem tumorskem bremenu v DNK tumorske celice (TMB-H). Potrebujemo še dodatne prediktivne bio-markerje, s pomočjo katerih se bomo bolj zanseljivo odločali o optimalnem zdravljenju bolnikov z RNI.
Keywords: imunoterapija, onkologija, onkološko zdravljenje
Published in DiRROS: 16.02.2023; Views: 435; Downloads: 204
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39. Assessing the heterogeneity and conservation status of the Natura 2000 priority forest habitat type Tilio–Acerion (9180*) based on field mappingJanez Kermavnar, Erika Kozamernik, Lado Kutnar, 2023, original scientific article Abstract: Priority habitat types (HTs) within the Natura 2000 network are of the highest importance for conservation in Europe. However, they often occur in smaller areas and their conservation status is not well understood. One such HT is that of the Tilio–Acerion forests of slopes, screes and ravines (9180*). The Natura 2000 study site, Boč–Haloze–Donačka gora, in the Sub-Pannonian region of eastern Slovenia is characterized by a matrix of European beech forests and includes rather small, fragmented areas covered by Tilio–Acerion forests. The goal of this research was to examine the heterogeneity and conservation status of the selected HT through field mapping, which was performed in the summer of 2020. As the conservation of HT calls for a more detailed approach, we distinguished between the following four pre-defined habitat subtypes: (i) Acer pseudoplatanus-Ulmus glabra stands growing mostly in concave terrain, (ii) Fraxinus excelsior stands growing on slopes, (iii) Tilia sp. stands with thermophilous broadleaves occurring on ridges and slopes, (iv) Acer pseudoplatanus stands occurring on more acidic soils with an admixture of Castanea sativa. Field mapping information was complemented with the assessment of habitat subtype characteristics using remote sensing data. The results showed that habitat subtypes differed significantly in terms of area, tree species composition, forest stand characteristics, relief features and the various threats they experienced (e.g., fragmentation, tree mortality, ungulate browsing pressure). The differences between subtypes were also evident for LiDAR-derived environmental factors related to topography (i.e., terrain steepness and Topographic Position Index). This study provides a baseline for setting more realistic objectives for the conservation management of priority forest HTs. Due to the specificities of each individual habitat subtype, conservation activities should be targeted to the Natura 2000 habitat subtype level.
Keywords: forest habitat subtype, monitoring, biodiversity conservation, LiDAR, Slovenia, NATURA 2000
Published in DiRROS: 03.02.2023; Views: 995; Downloads: 271
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40. Vpliv opustitve dopolnilne kemoterapije na preživetje bolnic z zgodnjim ER+/HER2+ rakom dojkValentina Jerič Horvat, Damjan Manevski, Barbara Gazić, Primož Drev, Domen Ribnikar, Erika Matos, Boštjan Šeruga, 2022, published professional conference contribution abstract Keywords: onkologija, rak dojke, kemoterapija
Published in DiRROS: 27.01.2023; Views: 414; Downloads: 113
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