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Enhancing the tribological performance of polyether ether ketone (PEEK) polymer using carbon-alloyed transition metal dichalcogenide coatings
No full textThe demand for light-weight polymeric materials such as polyether ether ketone (PEEK) is increasing for advanced engineering components, like polymeric gears. However, the intrinsic limitations of PEEK, including high friction, poor wear resistance, and rapid surface degradation restrict its larger adoption. This work is dedicated towards enhancing the dry sliding performance of PEEK via surface modifications. Direct current magnetron sputtered (DCMS) carbon-alloyed tungsten disulfide (WSC) coatings having C content of ∼52 at. % were deposited on PEEK polymer substrates at low power. Modifications of coating architecture were obtained by depositing coatings with and without inter/gradient layers. Comprehensive post-deposition characterization included chemical composition, cross-section and surface morphology, crystal structure, detailed chemical bonding, and coatings-PEEK adhesion investigations. The coatings were uniform, compact, amorphous, and provided complete surface alteration of PEEK with sufficient coating-polymer adhesion. Under ambient air sliding, the WSC coating with inter/gradient layer architecture exhibited the best performance, by reduction in friction coefficient (COF) and specific wear rate up to ∼34.3 % and ∼98.3 %, respectively relative to the uncoated PEEK. Post sliding Raman and X-ray photoelectron spectroscopy (XPS) revealed that C dominated the role in the reduction of COF and wear through the formation of a stable, partially graphitized tribolayer. This work establishes a scalable pathway for integrating solid-lubricant coatings on polymeric components, opening new opportunities for their reliable use in high-load and energy-efficient industrial systems
Hybrid thermalization in the large N limit
No full textSemi-holography provides a formulation of dynamics in gauge theories involving both weakly self-interacting (perturbative) and strongly self-interacting (non-perturbative) degrees of freedom. These two subsectors interact via their effective metrics and sources, while the full local energy-momentum tensor is conserved in the physical background metric. In the large N limit, the subsectors have their individual entropy currents, and so the full system can reach a pseudo-equilibrium state in which each subsector has a different physical temperature.
We first complete the proof that the global thermal equilibrium state, where both subsectors have the same physical temperature, can be defined in consistency with the principles of thermodynamics and statistical mechanics. Particularly, we show that the global equilibrium state is the unique state with maximum entropy in the microcanonical ensemble. Furthermore, we show that in the large N limit, a typical non-equilibrium state of the full isolated system relaxes to the global equilibrium state when the average energy density is large compared to the scale set by the inter-system coupling. We discuss quantum statistical perspectives
The effect of bisphenol PH and seven other bisphenol A alternatives on human haemostasis in vitro
No full textRecognition of bisphenol A’s toxicity has meant substitution by new analogues, which are poorly investigated. We determined the impact of bisphenol A and 8 of its analogues on platelet aggregation, coagulation, and their toxicity to erythrocytes. Erythrocyte lysis assays revealed bisphenol toxicity towards both human and rat erythrocytes with high TC> 100 μM. Bisphenol A and bisphenol PH acted as antiplatelet compounds. Bisphenol PH was particularly potent (IC of 0.42 ± 0.14 μM0.16 ± 0.05 μg/ml) in arachidonic acid-based platelet aggregation. Mechanistically, bisphenol PH blocked cyclooxygenase 1, in a similar manner to the antiplatelet drug acetylsalicylic acid. In terms of the coagulation cascade, only weak effects were found for some of the selected compounds, and the tested bisphenols did not impact coagulation or demonstrate erythrocytic toxicity at biologically achievable concentrations. Contrarily, the negative impact of bisphenol PH on platelets, with a possible subsequent risk of bleeding, might have biological relevance
The benefits of including a therapy dog for improving social skills of a child with moderate intellectual development disorder
No full textThe article is about the role of a therapy dog for the development of social skills in a student with a moderate intellectual disability. Our chosen student attends a special education programme. In the research, we focused mostly on the student\u27s social skills, such as communication, self-care (personal hygiene, eating, and dressing) and caring for others (for a therapy dog – feeding, brushing and walking the dog). We observed social skills such as releasing one\u27s own tension, promoting positive self-esteem, expressing emotions clearly, as well as recognizing emotions, and spatial orientation (in and out of school). The research process took the form of individual treatments. We found out that the involvement of a therapy dog had an effect on improving the student\u27s social skills. Improvements were seen in the areas of communication, self-care, recognition of emotions, release of one\u27s own tension and spatial orientation. The most noticeable progress in the student was improvement in communication, self-care and releasing her own tension. During the sessions with the therapy dog, the student was more active and motivated and communicated loudly and confidently. She even greeted, said goodbye, thanked, asked for something, told if something bothered her, brushed her hair, put a patch and bandage on, poured water into a glass, prepared a snack, expressed the need to retreat to a corner and expressed if she was afraid of something or if she did not want to do something. She correctly determined the right and left side and led us appropriately to the school gym, hall and playground
The influence of bentonite type on the release of metal ions and the aroma of white wine
No full textNamen magistrskega dela je bil ugotoviti vpliv šestih različnih komercialnih bentonitov ter časa njegovega dodatka na sproščanje kovinskih ionov in aromo mladega belega vina sorte laški rizling. Uporabljene so bile različne vrste bentonitov, natrijevi, kalcij-natrijevi, kalcijevi ter aktivirani kalcijevi bentoniti, kateri so bili dodani v treh časovnih točkah, v mošt, med fermentacijo in po končani fermentaciji. Vsebnost kovinskih ionov smo določili z metodo ICP-MS ter aromatične spojine s pomočjo metode SPME-GC/MS. V eksperiment smo vključili tudi simulirano staranje vina s pomočjo povišane temperature, da smo določili vpliv dodatka bentonita ter časa dodatka na staranje vina in izgubo sadnosti. Rezultati so jasno pokazali, da ima čas dodatka bentonita ključen vpliv na sproščanje kovinskih ionov. Dodatek med fermentacijo je pokazal najvišje vrednosti železa (1240,7 µg/L) in aluminija (720,9 µg/L). Najnižje vrednosti železa, ki je znan oksidant, pa so pokazale vrednosti pri dodatku natrijevega bentonita. Prav tako je bila najnižja vrednost bakra z vrednostjo 18,3 µg/L izmerjena pri natrijevem bentonitu, dodanem med fermentacijo. Aromatski profil, ki smo ga ocenjevali na podlagi sedmih skupin hlapih komponent, je bil najbolje ohranjen pri dodatku natrijevega bentonita med potekom alkoholne fermentacije. Po simuliranem staranju vina so se koncentracije povišale pri etilnih estrih maščobnih kislin, aromatičnih estrih in pri višjih alkoholnih acetatih, ki pomembno vplivajo na sadnost belega vina. Nasprotno je dodatek kalcijevega bentonita v mošt povzročil najvišje izgube aromatičnih spojin. Po rezultatih sklepamo, da je najbolj optimalna kombinacija za ohranitev profila arom ter zmanjšano prisotnost določenih kovinskih ionov, ki delujejo kot katalizatorji oksidacije, dodatek natrijevega bentonita med potekom alkoholne fermentacije.The aim of this master’s thesis was to determine the influence of six different commercial bentonites and the timing of their addition on the release of metal ions and the aroma of young white wine made from the Laški rizling variety. Different types of bentonites were applied—sodium, calcium-sodium, calcium, and activated calcium bentonites—each added at three different stages: to the must, during alcoholic fermentation, and after fermentation. Metal ion concentrations were determined using ICP-MS, while volatile aromatic compounds were analyzed using HS/SPME-GC/MS. The experiment also included simulated wine aging at elevated temperatures to assess the influence of bentonite type and timing on wine aging and loss of fruitness. The results clearly showed that the timing of bentonite addition has a key influence on the release of metal ions. Addition durig fermentation showed the highest values of iron (1240.7 µg/L) and aluminium (720.9 µg/L). The lowest values of iron, which is known oxidant, were shown by the values of addition of sodium bentonite. Similarly, the lowest copper content (18.3 µg/L) was also observed with sodium bentonite added during fermentation. The aromatic profile was evaluated based on seven groups of volatile compounds and was best preserved with the addition of sodium bentonite during alcoholic fermentation. After simulated aging of the wine, the concentrations increased in ethyl esters of fatty acids, aromatic esters and higher alcohol acetates, which significantly affect the fruitiness of white wine. On the contrary, the addition of calcium bentonite to the must caused the highest loss of aromatic compounds. According to the results, we conclude that the most optimal combination for preserving the aromatic profile and reducing the presence of certain metal ions that act as oxidation catalysts is the addition of sodium bentonite during alcoholic fermentation
Expression of subjective well-being according to the PERMA model among preschool teachers
No full textSubjektivno blagostanje strokovnih delavcev v vrtcu prestavlja pomemben vidik na vzgojno izobraževalnem področju. Strokovni delavci v vrtcu so ključni dejavnik prenosa pozitivne vzgoje na otroke, kjer želimo doseči pozitivno klimo in posledično spodbujati dobro subjektivno blagostanje oz. dobrobit otrok. Subjektivno blagostanje predstavlja osrednji koncept na področju pozitivne psihologije. Model PERMA opredeljuje pet elementov, ki prispevajo k subjektivnemu blagostanju: pozitivna oz. prijetna čustva, zavzetost oz. angažiranost, pozitivni medosebni odnosi, občutek smisla in dosežki. Model dopolnjuje pozneje dodani šesti element zdravje, zato lahko model poimenujemo tudi PERMA(H) ali PERMAH. V raziskavi smo preučevali subjektivno blagostanje po modelu PERMA(H) pri vzgojiteljicah predšolskih otrok in pomočnicah vzgojiteljice. Sodelovalo je 293 strokovnih delavcev v vrtcu, večinoma ženskega spola. Udeleženci so izpolnili vprašalnik PERMA-Profiler, ki meri subjektivno blagostanje po modelu PERMA(H). Rezultati raziskave so pokazali, da so strokovne delavke v vrtcu pri šestih elementih modela PERMA(H) dosegle najvišje rezultate pri občutku smisla ter najnižje rezultate pri zdravju, ki zajema samooceno telesnega in duševnega zdravja. Ugotovili smo tudi, da se vzgojiteljice in pomočnice vzgojiteljic statistično pomembno razlikujejo v subjektivnem blagostanju, in sicer vzgojiteljice poročajo o višjem subjektivnem blagostanju kot pomočnice vzgojiteljice. Dobro subjektivno blagostanje oz. dobrobit strokovnih delavk v vrtcu je prvi pogoj za kakovostno spodbujanje subjektivnega blagostanja oz. dobrobiti pri otrocih in ima pomembno vlogo tudi pri oblikovanju klime v oddelku in v vrtcu.
Diplomsko delo tako predstavlja pomemben doprinos k razumevanju področja subjektivnega blagostanja oz. dobrobiti strokovnih delavk v vrtcu in prispeva k ozaveščanju strokovne javnosti o pomembnosti blagostanja oz. dobrobiti pri strokovnih delavcih v vzgoji in izobraževanju.The subjective well-being of early childhood education professionals in kindergartens represents an important aspect of the preschool education. As key agents in the implementation of positive education, early childhood education professionals play a crucial role in creating a positive educational climate and fostering the subjective well-being of children. Subjective well-being is a central concept in positive psychology and is commonly conceptualized through the PERMA model, which defines five core elements contributing to well-being: positive emotions, engagement, positive relationships, meaning, and accomplishment. The model was later extended with a sixth element, health, resulting in the PERMA(H) model. The present study examined the subjective well-being of early childhood education professionals (i.e., preschool teachers and preschool teachers’ assistants) using the PERMA(H) framework. A total of 293 early childhood education professionals, predominantly women, participated in the study. Data were collected using the PERMA-Profiler questionnaire, which assesses subjective well-being across the dimensions of the PERMA(H) model. The results showed that participants reported the highest levels of well-being in the domain of meaning, while the lowest scores were observed in the domain of health, which includes self-assessments of physical and mental health. Furthermore, statistically significant differences were found between preschool teachers and preschool teachers’ assistants, with preschool teachers reporting higher overall levels of subjective well-being. The subjective well-being of early childhood education professionals is an important prerequisite for promoting children’s well-being and for creating and maintaining a positive climate within kindergarten groups and institutions. This diploma thesis contributes to a better understanding of subjective well-being among early childhood education professionals and raises awareness within the professional community about the importance of supporting well-being in kindergarten settings
Monitoring of measurable residual disease in patients with acute myeloid leukemia and NPM1 mutation
No full textAkutna mieloblastna levkemija (AML) je maligna bolezen krvotvornih matičnih celic, za katero je značilna nenadzorovana proliferacija in motena diferenciacija, kar vodi v odpoved normalne hematopoeze. Po klasifikaciji Svetovne zdravstvene organizacije je AML z mutacijo v genu NPM1 opredeljena kot samostojna genetska podvrsta bolezni. Gen NPM1 kodira protein, ki sodeluje v številnih celičnih procesih, vključno z biogenezo ribosomov, popravilom DNA ter regulacijo tumorsupresorskih poti. Mutacije v genu NPM1 (NPM1c), najpogosteje gre za insercije v eksonu 12, pa povzročijo izgubo tumorsupresorske funkcije, kar vodi v levkemično transformacijo. Zaradi specifičnosti in stabilnosti mutacije je NPM1 idealni tarčni označevalec za spremljanje merljivega preostanka bolezni (MRD), občutljivega laboratorijskega kazalnika, s katerim zaznavamo preostale levkemične celice, ki ostanejo v telesu bolnika po zdravljenju, zdravnikom pa omogoča oceno odziva na zdravljenje, napoved tveganja za ponovitev bolezni in pravočasno prilagajanje terapije. Po smernicah European LeukemiaNet (2021), ki so namenjene spremljanju bolnikov, ki se zdravijo z intenzivno kemoterapijo, je vrednotenje MRD pri NPM1c–AML priporočljivo po dveh ciklih indukcijske kemoterapije iz vzorca periferne krvi, po koncu konsolidacijskega zdravljenja iz vzorca kostnega mozga ter v fazi remisije, običajno vsake 3 mesece iz kostnega mozga ter vsakih 4–6 tednov iz periferne krvi v prvih dveh letih spremljanja. Za spremljanje MRD so primerne molekularne metode, najpogosteje kvantitativna PCR z reverzno transkripcijo.
Namen magistrske naloge je bil oceniti, kako dosledno se v klinični praksi upoštevajo evropske smernice za spremljanje MRD pri bolnikih z AML in NPM1c, ter preveriti, ali takšno spremljanje dejansko vpliva na klinične odločitve in izboljša obravnavo bolnikov. Poleg tega smo želeli primerjati spremljanje MRD pred in po uvedbi smernic leta 2021. Za raziskavo smo zbrali podatke 97 bolnikov, ki so se med leti 2016 in 2024 zdravili na Kliničnem oddelku za hematologijo. Ugotovili smo, da je bil pri 46,9 % bolnikov določen MRD po 2. ciklu kemoterapije, vendar je bil le pri 26,7 % odvzet priporočen vzorec (periferna kri), ob zaključku zdravljenja pa je 80 % bolnikov imelo določen MRD iz priporočenega vzorca (kostni mozeg). Pri spremljanju bolnikov smo ugotovili, da so bili bolniki, diagnosticirani pred uvedbo smernic, spremljani neenotno, z dolgimi časovnimi intervali med kontrolami, tudi nad enim letom, kar je pri nekaterih prispevalo k poznejšemu odkritju ponovitve bolezni. Po uvedbi smernic se je spremljanje izrazito izboljšalo, saj so kontrole postale pogostejše, bolj dosledne in večinoma skladne s priporočili. Prav tako so bolniki po alogenski presaditvi krvotvornih matičnih celic ostali spremljani še daljše časovno obdobje, medtem ko bolniki na manj intenzivni terapiji ali paliativni oskrbi niso bili spremljani.Acute myeloid leukemia (AML) is a malignant disease of hematopoietic stem cells, characterized by uncontrolled proliferation and impaired differentiation, leading to failure of normal hematopoiesis. According to the World Health Organization classification, AML with a mutation in the NPM1 gene is defined as a distinct genetic subtype of the disease. The NPM1 gene encodes a protein involved in numerous cellular processes, including ribosome biogenesis, DNA repair, and regulation of tumor suppressor pathways. Mutations in the NPM1 gene (NPM1c), most commonly insertions in exon 12, result in loss of tumor suppressor function, leading to leukemic transformation. Due to the specificity and stability of this mutation, NPM1 represents an ideal molecular target for monitoring measurable residual disease (MRD), a sensitive laboratory marker used to detect residual leukemic cells remaining in the patient’s body after treatment. MRD monitoring enables clinicians to assess treatment response, predict the risk of relapse, and adjust therapy in a timely manner. According to the European LeukemiaNet guidelines (2021), which are intended for monitoring patients receiving intensive chemotherapy, MRD assessment in NPM1-mutated AML is recommended after two cycles of induction chemotherapy using peripheral blood, after completion of consolidation therapy using bone marrow, and during remission, typically every 3 months from bone marrow and every 4–6 weeks from peripheral blood during the first two years of follow-up. Molecular methods are suitable for MRD monitoring, most commonly quantitative reverse transcription PCR (RT-qPCR).
The aim of this master’s thesis was to evaluate how consistently the European guidelines for MRD monitoring are applied in clinical practice for patients with AML and NPM1 mutation, and to determine whether such monitoring influences clinical decision-making and improves patient management. In addition, we aimed to compare MRD monitoring before and after the introduction of the guidelines in 2021. We collected data from 97 patients who were treated at the Department of Haematology between 2016 and 2024. We found that MRD was assessed after the second cycle of chemotherapy in 46,9 % of patientshowever, only 26,7 % had the recommended sample (peripheral blood) collected, whereas at the end of treatment, 80 % of patients had MRD assessed from the recommended sample (bone marrow). During follow-up, we observed that patients diagnosed before the introduction of the guidelines were monitored inconsistently, with long intervals between assessments, often exceeding one year, which in some cases contributed to delayed detection of disease relapse. After the implementation of the guidelines, monitoring improved markedly, as assessments became more frequent, more consistent, and largely aligned with recommendations. Patients who underwent allogeneic hematopoietic stem cell transplantation (allo-HSCT) continued to be monitored over a longer period, whereas patients receiving less intensive therapy or palliative care were generally not monitored
The art of communal drinking
No full textCommunal eating and drinking are universal human behaviours. They are culturally coded social practices involved in the formation of social identities through strategies of inclusion and exclusion – who is invited to a meal and who is not, who may or may not prepare and consume certain foods and drinks, what behaviours are expected of whom, and what material paraphernalia may be used by whom and in what context. Drinking vessels and their physical properties are often used strategically to either unify or diversify individuals and groups. The material culture of communal drinking is enmeshed in the formation, performance and negotiation of identities through the processes of social competition and cultural distinction. This paper examines the material aspects of late medieval drinking culture, focusing on the decorated ceramic drinking vessels that were used in the southern regions of Central Europe. Several distinct groups of medieval ceramic drinkware are presented, such as earthenware beakers and goblets with relief decoration and the Loštice semi-stoneware goblets. Their regional distribution, the social contexts in which they were used, and their relationship to drinking vessels made of other materials are discussed in terms of the role they played in the formation of late medieval social and cultural identities
Development of three-dimensional LES based meshless model of continuous casting of steel
No full textA large-eddy simulation (LES) based meshless model is developed for the three-dimensional (3D) problem of continuous casting (CC) of steel billet. The local collocation meshless method based on radial basis functions (RBF) is applied in 3D. The method applies scaled multiquadric (MQ) RBF with a shape parameter on seven nodded local sub-domains. The incompressible turbulent fluid flow is described using mass, energy, and momentum conservation equations and the LES turbulence model. The solidification system is solved with the mixture continuum model. The Boussinesq approximation for buoyancy and the Darcy approximation for porous media are used. Chorin’s fractional step method is used to couple velocity and pressure. The microscopic model is closed with the lever rule model. The LES model is compared to the two-equation Low Re k−ε turbulence Reynolds Averaged Navier–Stokes (RANS) model in terms of temperature, velocity and computational times. The LES model resolves transient character of vortices which RANS-type turbulence models are unable to tackle. The computational cost of LES models is considerably higher than in RANS. On the other hand, it results in a much lower computational cost than the direct numerical simulation (DNS). The paper demonstrates the ability of the method to solve realistic industrial 3D examples. Trivial adjustment of nodal densities, high accuracy, and low numerical diffusivity are the main advantages of this meshless method
Profiling of rose wines using various sensory methods
No full textMagistrska naloga obravnava tematiko senzoričnega profiliranja slovenskih rose vin z uporabo različnih senzoričnih metod. Namen naloge je bil prikazati, kako senzorične lastnosti, kot so barva, aroma in okus ter všečnost, vplivajo na percepcijo rose vina ter kako se te lastnosti povezujejo s fizikalno-kemijskimi parametri. V raziskavo je bilo vključenih petnajst vzorcev rose vin iz različnih slovenskih vinorodnih okolišev. S pomočjo štirih senzoričnih metod – hitrega profiliranja (Flash Profiling), metode »ovrednoti vse, kar ustreza« (RATA), 9-točkovne hedonske lestvice in razvrščanja po lastni presoji – smo pridobili celostno oceno vzorcev. Rezultati so pokazali, da barva in aromatski profil pomembno vplivata na senzorično zaznavo ter na končno oceno všečnosti. Vzorci svetlejše barve in izrazite sadne arome so bili ocenjeni kot najbolj sveži in uravnoteženi. Kvantitativne analize so potrdile povezavo med vsebnostjo fenolnih spojin in intenziteto barve, kar potrjuje vpliv polifenolov na senzorične značilnosti rose vina. Ugotovitve raziskave prispevajo k boljšemu razumevanju senzorične percepcije rose vin in lahko služijo kot podlaga za razvoj senzoričnih orodij v slovenski vinski industriji.The master\u27s thesis addresses the sensory profiling of Slovenian rosé wines using various sensory methods. The aim of the thesis was to demonstrate how sensory properties such as colour, aroma, taste, as well as liking influence the perception of rosé wine, and how these properties relate to physical and chemical parameters. Fifteen samples of rosé wines from different Slovenian wine-growing regions were included in the study. Using four sensory methods – Flash Profiling, the “rate all that applies” (RATA) method, the 9-point hedonic scale, and ranking by personal judgement – we obtained a comprehensive assessment of the samples. The results showed that colour and aromatic profile significantly influence sensory perception and the final assessment of liking. Samples with a lighter colour and a pronounced fruity aroma were assessed as the freshest and most balanced. Quantitative analyses confirmed the relationship between the content of phenolic compounds and colour intensity, which demonstrates the influence of polyphenols on the sensory characteristics of rosé wine. The findings of this research contribute to a better understanding of the sensory perception of rosé wines and can serve as a basis for developing sensory tools in the Slovenian wine industry