123903 research outputs found
Sort by
Greater thermophilisation in communities of juveniles than adults in temperate European forests
No full textAim
Warming of the climate system is increasing the dominance of warm-adapted species, a process referred to as thermophilisation. In forests, adult trees in the forest canopy experience warmer daytime summer conditions than juveniles in the understorey, but they are less susceptible to warming. These differences can result in differing thermophilisation rates between adults and juveniles. Here, we quantify for the first time the long-term thermophilisation of tree species in temperate European forests, comparing adults with juveniles.
Location
Europe.
Methods
We calculated the thermophilisation of adults and juveniles of forest tree species using layer-specific climatic data, species cover and occurrence data from 2202 resurveyed vegetation plots recorded twice between 1933 and 2017 and located across 12 European countries. We inferred species\u27 thermal profiles from species distribution maps matched to gridded open-air temperature (proxy for above-canopy macroclimate) for adults and to below-canopy microclimate temperature for juveniles.
Results
The thermophilisation rate in the juvenile layer was seven times higher than in the adult tree layer. The thermophilisation rates of both adults and juveniles were primarily driven by gains in relatively warm-adapted species and a concurrent, but less strong, decrease in cold-adapted species.
Conclusion
The compositional change in favour of more warm-adapted species was mainly driven by gains in warm-adapted species. The magnitude of these responses and the influencing variables were different in the community of adults and juveniles. These results underpin the importance of separately quantifying the responses of individuals throughout their life cycle to improve our ability to understand the impacts of environmental change on forest biodiversity and composition and apply targeted management actions
Numerical model for predicting wrinkling of toroidal shells with soft cores
No full textV nalogi je obravnavano gubanje toroidnih lupin z mehkimi jedri. Na osnovi teorije tankih lupin in Winklerjevega modela je bila zapisana energija sistema ter s Fourierjevimi vrstami predstavljena v numerični obliki. Z optimizacijo v Pythonu so bili iskani energijski minimumi in spremljan nastanek gubanja pri različnih obremenitvah. Rezultati pokažejo različne načine gubanja ter vpliv geometrije in togosti materiala na obliko deformacij.The thesis deals with the wrinkling of toroidal shells with soft cores. Based on thin shell theory and the Winkler model, the system energy was derived and expressed numerically using Fourier series. Optimization in Python was used to search for energy minima and to observe wrinkling under different loads. The results show different wrinkling modes and the influence of geometry and material stiffness on deformation shapes
Development of approaches for the isolation, activation and expansion of gamma delta T cells
No full textCelice γδ T so zaradi svojih protitumorskih sposobnosti obetavne imunske celice za celično imunoterapijo raka. V magistrskem delu smo razvijali metode za izolacijo, aktivacijo in namnožitev teh celic ex vivo z namenom vzpostavitve pristopov za pripravo celičnih produktov v prihodnosti. Razvoj je vključeval opazovanje vpliva sestave začetne kulture, različnih gojišč ter različnih aktivatorjev in njihove priprave. Iz krvi zdravih darovalcev smo z gradientnim centrifugiranjem izolirali mononuklearne celice periferne krvi, od katerih je bilo v povprečju 3,5 ± 1,7 % celic γδ T, med njimi pa je prevladoval podtip Vγ9Vδ2. Z metodo magnetno aktiviranega ločevanja celic smo očistili izolirane celice, da je bil delež celic γδ T v povprečju 75,4 ± 7,9 %. Za potrebe gojenja smo izmed treh gojišč identificirali najprimernejše, testirali pa smo tudi pripravo aktivatorja zoledronata. V najbolj optimiziranih pogojih je dodatek zoledronata neočiščenim kulturam aktiviral celice γδ T, da jih je bilo na koncu gojenja 97,0-krat več (± 22,8), predstavljale pa so 70,9 ± 19,6 % vseh celic. Zoledronat je selektivno namnožil podtip Vγ9Vδ2. Očiščene kulture celic γδ T smo aktivirali z dodatkom protiteles proti CD3, ki je povzročil 14,9-kratno (± 13,3) povečanje števila celic γδ T, ki so v končnih kulturah prevladovale s 87,7 ± 6,9 %. Aktivacija in namnožitev sta skupno potekali 14 dni v gojišču z ustreznimi citokini. S pretočno citometrijo smo pri namnoženih celicah potrdili za aktivacijo značilne spremembe fenotipa, s testom ELISA pa sposobnost izločanja efektorskih molekul. Razviti pristopi predstavljajo osnovo za pripravo γδ T-celičnih produktov za potencialno klinično uporabo.Gamma delta T cells are a promising candidate for cellular immunotherapy due to their potent antitumor activity. In our master’s thesis, we developed protocols for the isolation, activation, and expansion of these cells ex vivo, with the aim of establishing approaches for the preparation of cell products in the future. Our development process included examining the influence of the starting cell culture composition, different media types, various activators, and their methods of preparation. Peripheral blood mononuclear cells were isolated from buffy coats of healthy donors using gradient centrifugation, among which γδ T cells accounted for 3,5 ± 1,7 %, with the dominant subtype being Vγ9Vδ2. Further isolation using magnetic-activated cell sorting increased the γδ T cell proportion to 75,4 ± 7,9 %. For expansion purposes, we identified the most suitable among three growth media and we also tested the preparation of zoledronate. Under the most optimized conditions, adding activator zoledronate to bulk culture activated γδ T cells with expansion fold of 97,0 ± 22,8. They constituted 70,9 ± 19,6 % of all cells in expanded culture. Zoledronate selectively activated Vγ9Vδ2 subtype. We also activated preselected γδ T cells using the anti-CD3 antibody, which led to a 14,9-fold (± 13,3) increase in γδ T cell number. These cells made up 87,7 ± 6,9 % of the expanded population. The cells were cultured for 14 days in a medium with appropriate cytokines. Flow cytometry confirmed activation-associated phenotypic changes, while ELISA assays demonstrated the ability of the expanded cells to secrete efector molecules. The developed approaches provide a solid foundation for the production of γδ T cell-based products with potential clinical applications
Numerical simulation of the polyp formation due to secondary loss of stability in growing films on a soft viscoelastic substrates
No full textZa razumevanje kompleksnih biomehanskih mehanizmov, ki so vzrok za oblikovanje polipov v mehkih bioloških tkivih, smo analizirali relativno preprost prototipični primer gubanja rastočega tankega kolobarja (filma) na mehki viskoelastični podlagi. Ta primer smo obravnavali v programskem okolju FEniCS, ki vključuje tudi osnovne algoritme za reševanje parcialnih diferencialnih enačb, kot je Newton-Raphsonova metoda. Na podlagi izvedenih simulacij smo ugotovili, da na število gub in posledično število nastalih polipov vplivajo debelina tankega filma, notranji radij ter razmerje togosti podlage in filma. V nekaterih primerih pa smo opazili nepričakovane deformacijske oblike, ki jih ni mogoče predvideti na enostaven način, saj nastanejo zaradi nepojasnjenih preskokov sistema, ki so posledica nelinearne narave sistema zaradi geometrije in nelinearnega materialnega modela mehkih tkiv.To understand the complex biomechanical mechanisms that cause polyp formation in soft biological tissues, we performed an analysis of a relatively simple, prototypical example of wrinkling of a growing thin ring (film) on a soft viscoelastic substrate. We addressed this example in the FEniCS programming environment, which also includes basic algorithms for solving partial differential equations, such as the Newton-Raphson method. Based on the simulations performed, we found that the number of wrinkles, and consequently the number of resulting polyps, is influenced by the film\u27s thickness, its inner radius, and the stiffness ratio between the substrate and the film. In some cases, however, we observed unexpected deformation shapes that cannot be easily predicted. These arise from unexplained jumps in the system, which are a consequence of the system\u27s nonlinear nature due to its geometry and the nonlinear material model of soft tissues
Influence of the gender of the lymphoblastoid cell line donor on the immunomodulatory effects of selected bisphenols
No full textBisfenol A (BPA) in njegovi analogi so kemikalije, ki se uporabljajo pri proizvodnji plastike in epoksidnih smol, vendar je zaradi toksičnih učinkov njihova uporaba strogo nadzorovana. Delujejo kot motilci endokrinega sistema, saj vplivajo na delovanje hormonov, zlasti spolnih, preko katerih povzročajo različne biološke učinke, vključno z imunomodulatornimi. Zaradi njihovega vpliva na spolne hormone nas je zanimalo, ali obstajajo razlike v imunskem odzivu med spoloma po izpostavitvi izbranim bisfenolom.
Za preučevanje smo izbrali sedem bisfenolov, in sicer BPA, BPE, BPAF, BPAP, BPPH, TMBPF ter TCBPA. Kot model in vitro smo uporabili limfoblastoidne celične linije (LCL) zdravih, nesorodnih donorjev, in sicer pet LCL ženskih darovalk ter pet LCL moških darovalcev.
Najprej smo določili citotoksičnost izbranih spojin s testom presnovne aktivnosti MTS in izračunali srednje inhibitorne koncentracije - vrednosti IC50. Na podlagi povprečnih vrednosti IC50, določenih v desetih celičnih linijah LCL, so bile za preučevane bisfenole ugotovljene naslednje vrednosti (od najmanj do najbolj citotoksičnega): BPE (IC50 = 156,8 μM), TCBPA (IC50 = 124,7 μM), BPA (IC50 = 89,3 μM), BPAP (IC50 = 59,0 μM), BPAF (IC50 = 31,8 μM), BPPH (IC50 = 31,8 μM) in TMBPF (IC50 = 9,2 μM). S primerjavo vrednosti IC50 in logP smo ugotovili, da ti dve vrednosti med sabo korelirata, in sicer so bolj lipofilne spojine tudi bolj citotoksične. Naredili smo korelacijsko analizo med posameznimi vrednostmi IC50 bisfenolov v desetih testiranih LCL in ugotovili, da je najvišja korelacija med BPAF ter TCBPA. Ugotovili smo, da so pri vseh preučevanih bisfenolih povprečne vrednosti IC50 višje v celicah LCL moških v primerjavi s celicami LCL ženskih darovalk.
Pri preučevanju imunomodulatornih lastnosti izbranih bisfenolov z merjenjem izločenih citokinov smo ugotovili, da je vpliv na modulacijo izločanja citokinov odvisen od koncentracije spojine. Po izpostavitvi 10 μM koncentracijam so imele največji vpliv na izločanje citokinov spojine BPA, BPAF, TMBPF in BPPH, ki je izmed vseh deloval najbolj imunosupresivno. Bisfenoli v 100 nM koncentraciji so imeli nižji vpliv na modulacijo izločanja citokinov. Pri analizi interindividualnih razlik je bil opaženi spolno specifičen trend imunosupresivnega delovanja bisfenolov, z izrazitejšim učinkom pri moških, vendar brez statistično značilne razlike.
Iz rezultatov sklepamo, da bisfenoli izkazujejo različno stopnjo citotoksičnosti in imunomodulatornega delovanja, pri čemer so učinki odvisni tako od strukture spojine kot tudi od koncentracije. Opazili smo tudi spolno specifične trende v odzivu celic LCL, kar nakazuje na potencialno vlogo spolnih hormonov pri modulaciji učinkov teh spojin.Bisphenol A (BPA) and its analogues are chemicals used in the production of plastics and epoxy resins, but due to their toxic effects, their use is strictly regulated. They act as endocrine-disrupting chemicals, as they interfere with hormone function – particularly sex hormones – through which they cause various biological effects, including immunomodulatory ones. Because on their impact on sex hormones, we investigated whether there are differences in immune responses between genders following exposure to selected bisphenols.
We selected seven bisphenols for investigation: BPA, BPE, BPAF, BPAP, BPPH, TMBPF, and TCBPA. As an in vitro model, we used lymphoblastoid cell lines (LCLs) from healthy, unrelated donors – specifically, five female and five male LCLs.
First, we determined cytotoxicity of the selected compounds using the MTS assay and calculated the IC50 values. Based on the average IC50 values determined in ten LCL cell lines, the following IC50 values were obtained for the bispenols studied (from least to most cytotoxic): BPE (IC50 = 156,8 μM), TCBPA (IC50 = 124,7 μM), BPA (IC50 = 89,3 μM), BPAP (IC50 = 59,0 μM), BPAF (IC50 = 31,8 μM), BPPH (IC50 = 31,8 μM) and TMBPF (IC50 = 9,2 μM). Correlation analysis between IC₅₀ values and log P indicated that increased lipophilicity was associated with enhanced cytotoxic activity. A correlation analysis of IC50 values of bisphenols across ten tested LCLs revealed the highest correlation between BPAF and TCBPA. The average IC50 values were higher in LCLs derived from male donors compared to those from female donors.
Evaluation of the immunomodulatory properties of the selected bisphenols using cytokine release assays revealed that their effects were dose-dependent. The most pronounced immunomodulatory effects were observed for BPA, BPAF, TMBPF, and BPPH at higher, 10 μM concentration. The bisphenols caused a minor impact on cytokine secretion at 100 nM concentration. We observed sex-specific immunomodulatory effects of tested bisfenols, indicating that bisphenols may act more immunosuppressive in male cells.
In conclusion, bisphenols exhibited varying degrees of cytotoxicity and immunomodulatory activity, with effects depending on both the chemical structure of the compound and its concentration. We observed sex-specific trends in the response to bisphenols in LCL cells, indicating a potential role of sex in bisphenol-induced immunotoxicity
An infinite family of simple graphs underlying chiral, orientable reflexible and non-orientable rotary maps
No full textIn this paper, we provide the first known infinite family of simple graphs, each of which is the skeleton of a chiral map, a skeleton of a reflexible map on an orientable surface, as well as a skeleton of a reflexible map on a non-orientable surface. This family consists of all lexicographic products , where , with an integer not divisible by . This answers a question posed by Wilson in 2002
Analysis of benzodiazepines incidence in a group of new psychoactive substances between 2008 and 2024 in Europe
No full textNove psihoaktivne snovi (NPS) so sintetične ali naravno pridobljene snovi, ki posnemajo učinke prepovedanih drog, vendar zaradi njihove hitro spreminjajoče se sestave in pravnega statusa pogosto ostajajo izven obsega nadzora. Med temi snovmi so tudi benzodiazepini, ki so sicer pomembna skupina zdravil, a se v obliki novih derivatov pojavljajo tudi kot prepovedane droge.
V nalogi smo raziskovali pojavnost, uporabo in tveganja povezana z benzodiazepini v okviru NPS, zlasti v povezavi z zlorabo, kombiniranjem z drugimi substancami in vplivom na zdravje uporabnikov. Glavni vir informacij za izvedbo analize je predstavljala Evropska zbirka podatkov o novih drogah (EDND II).
Ugotovili smo, da je bilo v Evropi med letoma 2008 in 2024 na novo identificiranih 38 različnih benzodiazepinov. Največ novih benzodiazepinov (24) je bilo odkritih med 2014 in 2018, nato pa se je njihovo število začelo zmanjševati zaradi uspešnih preventivnih ukrepov. Švedska vodi po številu prijav uporabe novih benzodiazepinov, sledijo Nemčija in druge skandinavske države. Kljub majhni populaciji je Slovenija po številu prijav med vodilnimi v Evropi, saj smo prvič zaznali tri nove benzodiazepine, skupaj pa 14 različnih, kar predstavlja približno 37 % vseh prijavljenih različnih benzodiazepinov v bazi EDND II. Sedem teh benzodiazepinov je na slovenskem seznamu prepovedanih snovi, vsi v skupini I z visokim tveganjem za zlorabo in brez priznane medicinske uporabe, vendar za nobenega ni bila izdana ocena tveganja.
Večina vzorcev je bila zaseženih, največ v obliki tablet in praškov, novi benzodiazepini pa so se pogosto pojavljali skupaj z drugimi psihoaktivnimi snovmi, kar povečuje možnost smrtnih izidov. Leta 2020 so bili benzodiazepini prisotni v polovici vseh smrtnih primerov zaradi drog v Sloveniji, vendar se ta delež v zadnjih letih zmanjšuje.
Benzodiazepini predstavljajo pomemben dosežek v farmaciji kot učinkovita skupina zdravilnih učinkovin, vendar njihova zloraba kot NPS poudarja nujnost osredotočanja na zaščito zdravja posameznika, saj lahko nenadzorovana uporaba povzroči resne psihične in fizične posledice, tudi smrt.New Psychoactive Substances (NPS) are synthetic or naturally derived substances that mimic the effects of controlled drugs, but due to their rapidly changing composition and legal status, they often remain outside the scope of regulatory control. Among these substances are benzodiazepines, which, while significant as a class of medications, also appear as illicit drugs in the form of new derivatives.
In this study, we examined the occurrence, use, and risks associated with benzodiazepines within the context of NPS, particularly in relation to misuse, combination with other substances, and the impact on users’ health. The main source of informations for the analysis was the European Database on New Drugs (EDND II).
We found that between 2008 and 2024, a total of 38 different benzodiazepines were newly identified in Europe. The highest number of new benzodiazepines (24) was discovered between 2014 and 2018, after which their number began to decline due to successful preventive measures. Sweden leads in the number of reported cases involving new benzodiazepines, followed by Germany and other Scandinavian countries. Despite its small population, Slovenia ranks among the leading European countries in the number of reports, as we were the first to detect three new benzodiazepines, and identified a total of 14 different ones - representing approximately 37 % of all different benzodiazepines reported in the EDND II database. Seven of these benzodiazepines are listed on Slovenian list of prohibited substances, all in Group I with a high risk of abuse and no recognized medical use, although no risk assessment has been issued for any of them.
Most of the samples were seized, predominantly in tablet and powder form. New benzodiazepines frequently appeared alongside other psychoactive substances, increasing the risk of fatal outcomes. In 2020, benzodiazepines were present in half of all drug-related deaths in Slovenia, although this proportion has declined in recent years.
Benzodiazepines represent a significant achievement in pharmacy as an effective group of medicinal compounds, but their misuse as NPS highlights the urgent need to focus on protecting individual health, as unregulated use can lead to serious mental and physical consequences, including death
Moving through Cartesian products, coronas and joins in general position
No full textThe general position problem asks for large sets of vertices such that no three vertices of the set lie on a common shortest path. Recently a dynamic version of this problem was defined, called the mobile general position problem, in which a collection of robots must visit all the vertices of the graph whilst remaining in general position. In this paper we investigate this problem in the context of Cartesian products, corona products and joins, giving upper and lower bounds for general graphs and exact values for families including grids, cylinders, Hamming graphs and prisms of trees
Development of an innovative rotating disc electrode model for use in virtual sensors for detecting the ageing of catalytic material
No full textStaranje elektrokatalitskih materialov je eden izmed ključnih izzivov pri ohranjanju delovanja in učinkovitosti gorivnih celic. Eksperimentalni pristopi določanja in karakterizacije katalitske degradacije so pogosto dolgotrajni ter zahtevajo natančno laboratorijsko delo. V magistrski nalogi je predstavljen razvoj inovativnega modela rotirajoče disk elektrode (RDE) za uporabo v virtualnih zaznavalih staranja katalitskega materiala. Predstavljen model gradi na fizikalno in elektrokemijsko konsistentnem opisu procesov v RDE na način, da z uporabo analitično podprtega opisa tokovnega polja, poenostavljenih transportnih enačb in termodinamsko konsistentne elektrokemijske kinetike omogoča zanesljivo ločevanje med kinetičnimi in difuzijskimi prispevki elektrokemijskega odziva. Model je bil validiran na eksperimentalnih podatkih z uporabo globalnega optimizacijskega algoritma. Prav tako je bila preverjena možnost poenostavitve modela na podlagi analize Fisherjeve informacijske matrike z namenom določanje občutljivosti in enolične določljivosti parametrov. Rezultati kažejo, da virtualno zaznavalo zelo dobro napove evolucijo polarizacijske krivulje tekom degradacije katalizatorja, vrednost R-kvadrat je namreč vedno večja od 0,99, kar omogoča uspešno sledenje indikatorjev zmogljivosti in staranja, kot je izguba masne aktivnosti. Model omogoča prilagodljivo in računsko učinkovito alternativo eksperimentalni karakterizaciji ter hkrati odpira možnost spremljanja staranja katalizatorja znotraj gorivne celice v realnem času.Ageing of electrocatalytic materials is one of the key challenges in sustaining the long-term performance and effectiveness of fuel cells. Experimental approaches of catalytic degradation characterization are often time consuming and require extensive laboratory work. This thesis presents development of innovative rotating disc electrode model for use in virtual sensors for detecting the ageing of catalytic material is presented. The presented model builds upon physically and electrochemically consistent description of processes in RDE, using an analytically supported description of the current field, simplified transport equations, and thermodynamically consistent electrochemical kinetics, it enables reliable separation between kinetic and diffusion contributions of the electrochemical response. The model was validated on experimental data using global optimization algorithm. Furthermore, the possibility of simplifying the model was examined based on an analysis of the Fisher information matrix, with the aim of determining parameter sensitivity and identifiability. The results show that virtual sensor predicts the evolution of polarization curve during catalytic degradation very accurately, as the R-squared value is always greater than 0,99, which enables reliable tracking of performance and aging indicators such as mass activity loss. The model provides a flexible and computationally efficient alternative to experimental characterization as well as opens up the possibility of monitoring catalyst aging within fuel cell in real time
Trajnostna moda za otroška oblačila
No full textTextile waste has become a serious global problem, leading to pollution, resource depletion and overcrowding in landfills. To overcome these problems, sustainable design strategies that reduce resource consumption, minimize waste and maintain ecological balance are needed. Additionally, children\u27s rapid growth demands regular clothes changes, which generates a great deal of fabric waste. This highlights a serious research gap in creative, adaptable and waste-reducing ideas for children\u27s clothing, which affects the sustainability of the textile industry. This study explores the potential of permanent pleating in children’s clothing to develop sustainable, innovative designs that minimize waste and improve garment durability. In particular, permanent pleating in both the lengthwise and widthwise directions are investigated, while the durability and fit of pleated garments are assessed, as well as manufacturing limitations and challenges. Permanent pleating was applied to 100% polyester, a polyester-cotton blend, and 100% cotton fabrics using pleating moulds and three distinct methods: oven drying, oven drying with water mugs and steaming. The results revealed that the steaming method yielded the most successful permanent pleats on 100% polyester fabric, outperforming the polyester-cotton blend and 100% cotton fabrics. Permanent pleating reduces frequent clothing replacement by allowing the fabric to expand and fit various body sizes without losing structural integrity. This extends the lifespan of clothing and reduces textile waste.Tekstilni odpadki so postali resen svetovni problem, ki vodi do onesnaževanja, izčrpavanja virov in prenatrpanosti odlagališč. Za premagovanje teh težav so potrebne trajnostne strategije oblikovanja, ki zmanjšujejo porabo virov in količino odpadkov ter ohranjajo ekološko ravnotežje. Hitra rast otrok zahteva redno menjavo oblačil, kar povzroča veliko odpadkov tkanin. Na tem področju primanjkuje zamisli za zmanjšanje količine odpadkov otroških oblačil, kar vpliva na trajnostno učinkovitost tekstilne industrije. V raziskavi je proučevan potencial plisiranja otroških oblačil, da bi zmanjšali količino odpadkov in podaljšali trajnost oblačil. Proučevani so bili trajno plisiranje v vzdolžni in prečni smeri blaga, obstojnost gub, prileganje plisiranih oblačil, omejitve pri izdelavi in izzivi. Trajno plisirane so bile tkanine iz 100-odstotnega poliestra, mešanice poliestra in bombaža ter 100-odstotnega bombaža. Uporabljeni so bili kalupi za plisiranje in tri metode: sušenje v pečici, sušenje v pečici z vodnimi vrčki in parjenje. Pokazalo se je, da parjenje omogoča trajne gube na tkaninah iz 100-odstotnega poliestra, ki so obstojnejše kot na tkaninah iz mešanice poliestra in bombaža oziroma iz 100-odstotnega bombaža. Plisiranje zmanjšuje pogosto menjavo oblačil, saj omogoča, da se tkanina razširi in prilega različnim velikostim telesa, ne da bi pri tem izgubila strukturno celovitost. Tako se oblačila nosijo dalj časa, s tem pa je tudi tekstilnih odpadkov manj