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Priprava besedil za prispevke na Akademski televiziji: med normo, stilom in večznakovnostjo
No full textPrikazana je analiza besedil študentske informativno-eksperimentalne oddaje Študentsko oko v zadnjih treh študijskih letih (2021/22–2023/24). Ponazorjeni so najpogostejši odkloni od norme, stilistične posebnosti in priljubljene strukture ter nekatere utemeljitve študentov o jezikovnih odločitvah. Največ časa je treba posvetiti tvorbi besedila kot celote, jasnosti in razumljivosti, saj so slovnične napake skoraj odpravljene in so posledica spregledov, ne pa neznanja.This article analyzes texts from the experimental student news broadcast Študentsko oko (Student Eye) over the last three academic years (2021/22‒2023/24). Attention is drawn to the most frequent deviations from the norm, special stylistic features, and popular structures, as well as some of the students’ justifications for their linguistic choices. The most time was dedicated to producing the texts as a whole, clarity, and comprehensibility because there are almost no grammatical errors, and any mistakes are the result of oversights rather than ignorance
Development and optimisation of multistep desmethoxysulfazecin synthesis
No full textOkužbe so vodilni vzrok smrti po celem svetu, samo v letu 2019 so povzročile smrt 13,7 milijonov ljudi, izmed njih jih je vsaj 1,27 milijona umrlo neposredno zaradi infekcij z bakterijami, ki so odporne na antibiotike. β-Laktamski antibiotiki so najučinkovitejše orožje proti bakterijskim infekcijam, a so zaradi (pre)pogoste in nepravilne rabe bakterije razvile rezistenco na njih. Najbolj klinično relevanten mehanizem rezistence na β-laktamske antibiotike je inaktivacija z β-laktamazami. Proti serinskim β-laktamazam imamo učinkovite zaviralce, proti bakterijam, ki so razvile metalo β-laktamaze, pa so učinkoviti samo še monobaktami. V magistrski nalogi smo zato razvili in optimizirali večstopenjsko kemijsko sintezo desmetoksisulfazecina, ki je prekurzor edinega naravnega monobaktama s protibakterijskim delovanjem – sulfazecina.
Desmetoksisulfazecin smo sintetizirali po večstopenjski asimetrični sintezni poti. Pri sintezi amina smo izhajali iz L-serina, ki smo ga na amino skupini (-NH2) zaščitili s terc-butilkarbamatom, na prosto karboksilno skupino (COOH) pa smo vezali amin, zaščiten z benzil etrom. Nato smo dušik iz novonastalega amida povezali s C-3 ogljikom v β-laktamski obroč. Na sekundarni dušik smo nato dodali še eno zaščitno skupino terc-butilkarbamata, nato pa s hidrogeniranjem odstranili benzil eter, kar nam je omogočilo sulfoniranje dušika v β-laktamskem obroču. Na koncu smo v kislem odstranili še obe terc-butilkarbamatni zaščitni skupini in izolirali amin 7a.
Sintezo karboksilne kisline (stranske verige desmetoksisulfazecina) smo začeli z 2-pirolidon-5-karboksilno kislino, katere prosto COOH skupino smo zaščiti z benzilom, amino skupino pa z benzil karbamatom. Pirolidonski obroč smo nato odprli in na prosto karboksilno skupino vezali s terc-butilnim estrom zaščiten D-alanin, ki smo ga nato odščitili in izolirali prosto karboksilno kislino 12. Spojini 7a in 12 smo nato povezali v amid, kateremu smo na koncu sočasno odstranili še benzilno in benzilkarbamatno zaščitno skupino in izolirali spojino 21. Vse spojine, ki smo jih pridobili tekom sinteze, smo ovrednotili z jedrsko magnetno resonanco, nove spojine pa še z masno spektrometrijo.Infections are becoming the leading cause of death worldwide. In 2019 alone, microbial infections caused 13.7 million deaths worldwide, of which at least 1.27 million were directly linked to infections with antibiotic-resistant bacteria. β-Lactam antibiotics remain the most effective weapon against bacterial infections, but due to frequent and often improper use, bacteria are increasingly developing resistance to them. The most clinically relevant mechanism of resistance to β-lactam antibiotics is inactivation by β-lactamases. While effective inhibitors exist for serine β-lactamases, only monobactams remain effective against bacteria that are expressing metallo-β-lactamases. Therefore, in this master’s thesis, we have developed and optimized a multi-step synthetic route to desmethoxysulfazecin, a precursor to the only naturally occurring monobactam with antibacterial activity (i.e. sulfazecin).
Desmethoxysulfazecin was synthesized via a multi-step asymmetric synthetic route. The synthesis of the requisite amine was initiated from L-serine, which was protected on the amino group (-NH2) with a tert-butyl carbamatethe free carboxyl group (COOH) was then coupled with an amine protected by a benzyl ether group. The nitrogen atom of the newly formed amide was then linked to the C-3 carbon on the β-lactam ring. A second tert-butyl carbamate protecting group was then added onto the secondary nitrogen, and after removing the benzyl ether by hydrogenation, the sulfonation of the nitrogen atom in the β-lactam ring was achieved. Finally, both tert-butyl carbamate protecting groups were cleaved under acidic conditions, enabling the isolation of amine 7a.
The synthesis of the carboxylic acid sidechain began with 2-pyrrolidone-5-carboxylic acid, whereas its free COOH group was first protected as benzyl ether and the amino group with benzyl carbamate protecting group. The pyrrolidone ring was then opened, and the free carboxyl group was coupled with tert-butyl ester-protected D-alanine, which was subsequently deprotected to isolate free carboxylic acid 12. Compounds 7a and 12 were then coupled into an amide, after which the benzyl and benzyl carbamate protecting groups were simultaneously removed, yielding compound 21. All compounds obtained during the synthesis were evaluated using nuclear magnetic resonance (NMR), and new compounds were further analysed using mass spectrometry
Preparation of a cosmetic product safety report for a selected hair conditioner
No full textBalzami za lase predstavljajo nepogrešljiv del kozmetične nege, namenjene izboljšanju strukture, videza in zdravja las. Njihova primarna funkcija je zagotavljanje ustrezne hidracije, zmanjševanje poškodb, ki nastanejo zaradi mehanskih in kemičnih vplivov, ter olajšanje česanja. Z naraščajočim zanimanjem za nego las in razvojem inovativnih formulacij so balzami postali ključni izdelek v vsakodnevni rutini mnogih posameznikov.
V magistrski nalogi je predstavljena toksikološka ocena varnosti kozmetičnega izdelka – balzama za lase, v skladu z Uredbo (ES) št. 1223/2009 in smernicami Znanstvenega odbora za varnost potrošnikov (SCCS). Osrednji cilj raziskave je bil ovrednotiti varnost posameznih sestavin izdelka ob upoštevanju njihove koncentracije v formulaciji, ocenjene dermalne absorpcije, sistemski izpostavljenosti (SED) in razpoložljivih podatkov o najvišjih odmerkih, pri katerih še ni bilo opaženih neželenih učinkov (NOAEL).
V nalogi so predstavljeni tudi osnovni principi toksikološke ocene, struktura poročila o varnosti kozmetičnega izdelka in zakonodajni okvir. Naloga tako nudi celovit vpogled v praktično izvedbo ocene varnosti ter vlogo strokovno usposobljene osebe pri zagotavljanju skladnosti izdelkov na trgu.
Za vse sestavine smo iz znanstvene literature ter regulatornih virov zbrali temeljne fizikalno-kemijske lastnosti, toksikološke profile in ostale ustrezne podatke (podatke o dermalni absorpciji in vrednostih NOAEL). Za oceno tveganja smo uporabili pristop MoS (meja varne uporabe) in ugotovili, da vse sestavine, vključene v formulacijo, presegajo varnostni prag MoS ≥ 100, kar pomeni, da je izdelek varen za uporabo v predvidenih pogojih.
Izvedeni preračuni potrjujejo, da je obravnavani balzam za lase varen za potrošnike pri predvideni uporabi ter v celoti skladen z zahtevami veljavne evropske kozmetične zakonodaje.Hair conditioners represent an indispensable part of cosmetic care aimed at improving the structure, appearance, and health of the hair. Their primary function is to provide adequate hydration, reduce damage caused by mechanical and chemical influences, and facilitate combing. With growing interest in hair care and the development of innovative formulations, conditioners have become a key product in the daily routine of many individuals.
This Master\u27s thesis presents a toxicological safety assessment of a cosmetic product – a hair conditioner – in accordance with Regulation (EC) No. 1223/2009 and the guidelines of the Scientific Committee on Consumer Safety (SCCS). The main objective of the research was to evaluate the safety of individual ingredients in the product, taking into account their concentration in the formulation, estimated dermal absorption, systemic exposure dose (SED), and available data on the No Observed Adverse Effect Level (NOAEL).
The thesis also outlines the basic principles of toxicological assessment, the structure of the cosmetic product safety report, and the legislative framework. Thus, it provides a comprehensive insight into the practical implementation of safety assessment and the role of the qualified safety assessor in ensuring product compliance on the market.
For all ingredients, basic physicochemical properties, toxicological profiles, and other relevant data (including dermal absorption and NOAEL values) were collected from scientific literature and regulatory sources. The Margin of Safety (MoS) approach was used for risk assessment, and it was determined that all ingredients included in the formulation exceed the safety threshold of MoS ≥ 100, indicating that the product is safe for use under the intended conditions.
The calculations performed confirm that the hair conditioner under consideration is safe for consumers when used as intended and is fully compliant with the requirements of current European cosmetic legislation
Edge-transitive cubic graphs: analysis, cataloguing and enumeration
No full textThis paper deals with finite cubic (3-regular) graphs whose automorphism group acts transitively on the edges of the graph. Such graphs split into two broad classes, namely arc-transitive and semisymmetric cubic graphs, and then these divide respectively into 7 types (according to a classification by Djoković and Miller (1980) [17]) and 15 types (according to a classification by Goldschmidt (1980) [23]), in terms of certain group amalgams. Such graphs of small order were previously known up to orders 2048 and 768, respectively, and we have extended each of the two lists of all such graphs up to order 10000. Before describing how we did that, we carry out an analysis of the 22 amalgams, to show which of the finitely-presented groups associated with the 15 Goldschmidt amalgams can be faithfully embedded in one or more of the other 21 (as subgroups of finite index), complementing what is already known about such embeddings of the 7 Djoković-Miller groups in each other. We also give an example of a graph of each of the 22 types, and in most cases, describe the smallest such graph, and we then use regular coverings to prove that there are infinitely many examples of each type. Finally, we discuss the asymptotic enumeration of the graph orders, proving that if is the number of cubic edge-transitive graphs of type on at most vertices, then there exist positive real constants and and a positive integer such that for all
Predicting trajectories of temperate forest understorey vegetation responses to global change
No full textPredicting forest understorey community responses to global change and forest management is vital given the importance of the understorey for biodiversity conservation and forest functioning. Though substantial effort has gone into disentangling the impact of global change on understorey communities, scarcity of information on site-specific environmental drivers across large temporal-spatial scales has limited our ability to predict global change effects at specific forest sites. In this study, using vegetation resurvey and soil data from 1363 plots across temperate Europe, we applied a machine learning approach (gradient boosting regression, GBR) to model and predict site-specific responses of four understorey properties to global change. We applied our final GBR models at 8 forest sites in Austria to validate the model performance, predict understorey trajectories, and evaluate the effect of alternative scenarios for future nitrogen(N) deposition, climate change and forest management on the projected trajectories. Our results showed that the R² value of the four final GBR models on the independent testing dataset ranged between 0.611 and 0.723 and the most important environmental drivers in predicting the trajectory of understorey properties at specific forest sites were soil pH, soil total carbon-to-nitrogen ratio, overstorey shade-casting ability and regional-scale mean annual precipitation. The out-of-sample R2 value of the four final GBR models on the Austrian data ranged between 0.224 and 0.561. The forecasted trajectories for the Austrian forest sites showed that site-specific understorey responses to near-future climate warming were expected to be weak. Under N deposition decreases, the proportion of woody species was predicted to increase, while species richness and total vegetation cover were predicted to decrease. Furthermore, under a closed canopy, the understorey community was predicted to shift towards more woody species and more forest specialists, albeit with reduced species richness and vegetation cover. Given expected warming and declining N pollution pressures, our presented GBR models allow the prediction of trajectories of understorey vegetation responses to global change and management interventions at specific forest sites. Such projections could aid forest management in addressing challenges posed by global change
Developing an integrative management plan for urban and peri-urban forests
No full textMany cities worldwide have adopted management strategies for urban forests, typically focusing on forest parks, street trees and park trees. However, planning that concentrates on natural urban forest areas remains scarce. This study introduces an advanced planning framework for the integrative management of natural urban forests and applies it to Ljubljana\u27s urban forests (2151 ha). The framework consists of an initiation phase and a six-step planning procedure. Through a comprehensive process lasting 20 months, with strong stakeholder involvement and political support, we developed a strategic plan for Ljubljana’s entire urban forest area and an operational plan for a specific block within this area. The approach employs the integrative management of forest stands within or near the city, incorporating harmonised activities in silviculture, recreation, protection, harvesting and communication. This planning method aims to bridge the gap between traditional forest management planning and urban green infrastructure planning
Development of electrophilic coumarin derivatives for long-term fluorescent cell labelling
No full textFluorescenčne sonde so postale nepogrešljivo orodje pri raziskavah celične dinamike, prepoznavanju biomolekul ter spremljanju medceličnih interakcij v realnem času. Kljub široki uporabi je komercialno dostopnih le omejen nabor sond, ki imajo visoko fotostabilnost, selektivnost in biokompatibilnost.
Tovrstne sonde izkoriščajo fenomen fluorescence. Fluorofor ob obsevanju s svetlobo določene valovne dolžine absorbira foton in preide v vzbujeno stanje ter nato odda svetlobo pri daljši valovni dolžini. Razlika med valovno dolžino absorbirane in emitirane svetlobe je Stokesov premik. Fluorofori z velikim Stokesovim premikom, ustrezno fotostabilnostjo in specifičnostjo so še posebej primerni za opazovanje s konfokalno mikroskopijo.
Namen magistrske naloge je bil razvoj novih fluorescenčnih označevalcev na osnovi kumarinskega obroča s trifluorometilno skupino na položaju 4 ter elektrofilno skupino na položaju 3, ki bi omogočala reakcije s spojinami, ki vsebujejo tiolno skupino. Pri tem smo preučili različne sintezne poti za vpeljavo različnih elektrofilnih skupin. Trem pripravljenim označevalcem (11, 18, 19) smo pomerili ekscitacijski in emisijski spekter ter potrdili ustreznost spektralnih lastnosti. Nato smo preverili njihovo sposobnost označevanja živih celic, morebitno citotoksičnost in fotostabilnost s konfokalno mikroskopijo na celični liniji mišjega pljučnega epitelija (LA-4). Na podlagi fizikalno-kemijskih lastnosti smo pričakovali označevanje lipidnih kapljic v teh celic.
Pri nobeni od testiranih sond med meritvami nismo opazili citotoksičnih učinkov na žive celice. Najmanj fotostabilna sonda je bila sonda 11, medtem ko je sonda 19 med meritvami tvorila agregate. Nobena od sond ni izkazala izključno selektivnosti za lipidne kapljice, saj so označevale tudi druge celične organele. Ne glede na to, pa so pripravljene spojine uporabni intermediati za pripravo različnih fluorescenčnih sond.Fluorescent sondes have become an indispensable tool in researching cell dynamics, identifying biomolecules, and monitoring intercellular interactions in real time. Despite their widespread use, only a limited set of sondes with high photostability, selectivity, and biocompatibility are commercially available.
These markers utilise the phenomenom of fluorescence. When a phorophore is illuminated with light of a certain wavelenght, it absorbs a photon and transitions to an excited state, then emits light at a longer wavelenght. The difference between the absorbed and emitted wavelengths is known as the Stokes shift. Fluorophores with a large Stokes shift, high photostability, and specificity are particularly suitable for confocal microscopy.
This master\u27s thesis aimed to develop new fluorescent markers based on coumarin ring containing a trifluoromethyl group at position 4 and an electrophilic group at position 3, enabling reactions with compounds containing a thiol group. We studied various synthetic routes to introduce different electrophilic groups.. We measured the excitation and emission spectra of three prepared markers (11, 18, 19) and confirmed the suitability of their spectral properties. We then tested their labelling ability, potential cytotoxicity and photostability using confocal microscopy on a mouse lung epithelial cell line (LA-4). Based on the physicochemical properties of the markers, we expected selective labeling of lipid droplets.
We did not observe any cytotoxic effects during measurements. Sonde 11 demonstrated the lowest photostability, while sonde 19 formed aggregates during measurements. None of the sondes showed exclusive selectivity for lipid droplets, as they also labeled other cellular organelles. Nevertheless, the synthesized compounds represent useful intermediates for the development of various fluorescent probes
Spreminjanje lastnosti 2D materialov z molekulsko funkcionalizacijo
No full textThis thesis explores the modification of monolayer molybdenum disulfide (MoS) with the organic molecule 6-(4,5-Dihydro-1-imidazol-3-ium-2-yl)-2-(naphthalene-2-yl)benzothiazole methanesulfonate (L63MS) using a drop-casting method under ambient conditions. Given it’s planar, electron‐delocalized scaffold and bulky sulfonate counterion, L63MS is expected to adsorb via stacking, tuning its electronic structure while potentially preventing ordered self‐assembly and passivating the surface. MoS samples were synthesized via CVD and characterized using AFM, Raman spectroscopy, and PL spectroscopy to assess the impact of the organic molecule on the structural and opto-electronic properties of the material.
The study evaluates the effects of both the solvents used in the drop-casting process and the L63MS molecule itself on MoS. Results show that the L63MS molecule adsorbs onto the MoS surface, inducing measurable changes in the Raman spectra, PL signal, and excitonic properties. These changes suggest potential modifications in doping levels, bandgap, and defect states, all of which are influenced by the choice of solvent in the process. The modification remains stable over time under ambient conditions, and the original optical properties of MoS can be restored by heating, indicating the reversibility of the organic molecule\u27s effects. Finally, we demonstrate laser-assisted formation of molecular agglomerates on MoS surface at elevated substrate temperaturesthese agglomerates remain stable after subsequent thermal treatment.
This work provides insights into the stable, reversible modification of 2D MoS through organic molecules, with an emphasis on the role of solvents in the process.Ta disertacija preučuje modifikacijo enoslojnega molibdenovega disulfida (MoS) z organsko molekulo 6-(4,5-Dihydro-1-imidazol-3-ium-2-yl)-2-(naphthalene-2-yl)ben-zotiazol metansulfonat (L63MS) z metodo kapljičnega nanašanja pri normalnih sobnih pogojih. Glede na to, da je L63MS ploskovit, elektronsko delokaliziran in ima obsežen sulfonatni protiion, je pričakovati, da se bo adsorbiral prek zlaganja, s čimer bo prilagodil svojo elektronsko strukturo in hkrati preprečil urejeno samosestavljanje ter pasiviral površino. Vzorci MoS so bili sintetizirani s CVD metodo in analizirani z uporabo AFM-a, Raman spektroskopije in PL spektroskopije za oceno vpliva organske molekule na strukturne in optoelektronske lastnosti materiala.
Študija ocenjuje učinke tako topil, uporabljenih v procesu kapljičnega nanašanja, kot tudi same molekule L63MS na MoS. Rezultati kažejo, da se molekula L63MS adsorbira na površino MoS in povzroča merljive spremembe v Raman spektru, PL signalu in ekscitonskih lastnostih. Te spremembe nakazujejo možne modifikacije v ravneh dopiranja, energijski vrzeli in defektnih stanjih, pri čemer je vse našteto odvisno od izbranega topila. Poleg tega modifikacija ostane stabilna skozi čas pri normalnih pogojih, optične lastnosti MoS pa se lahko povrnejo s segrevanjem, kar kaže na reverzibilnost učinkov organske molekule. Na koncu smo prikazali lasersko podprto tvorbo molekularnih aglomeratov na površini MoS pri povišanih temperaturah podlageti aglomerati ostanejo stabilni tudi po nadaljnji toplotni obdelavi.
Ta disertacija nudi vpogled v stabilno in reverzibilno modifikacijo 2D MoS z organskimi molekulami, s poudarkom na vlogi topil v procesu
Cross-positive linear maps, positive polynomials and sums of squares
No full textA -linear map between matrix spaces is cross-positive if it is positive on orthogonal pairs of positive semidefinite matrices in the sense that implies , and is completely cross-positive if all its ampliations are cross-positive. (Completely) cross-positive maps arise in the theory of operator semigroups, where they are sometimes called exponentially-positive maps, and are also important in the theory of affine processes on symmetric cones in mathematical finance. To each as above a bihomogeneous form is associated by . Then is cross-positive if and only if is nonnegative on the variety of pairs of orthogonal vectors . Moreover, is shown to be completely cross-positive if and only if is a sum of squares modulo the principal ideal . These observations bring the study of cross-positive maps into the powerful setting of real algebraic geometry. Here this interplay is exploited to prove quantitative bounds on the fraction of cross-positive maps that are completely cross-positive. Detailed results about cross-positive maps mapping between matrices are given. Finally, an algorithm to produce cross-positive maps that are not completely cross-positive is presented
Extreme mass distributions for quasi-copulas
No full textThe recent survey [3] nicknamed “Hitchhiker’s Guide” has raised the rating of quasi-copula problems in the dependence modeling community in spite of the lack of statistical interpretation of quasi-copulas. In our previous work we addressed the question of extreme values of the mass distribution associated with a mutidimensional quasi–copulas. Using linear programming approach we were able to settle [3, Open Problem 5] up to and disprove a recent conjecture from [14] on solution to that problem. In this note we use an analytical approach to provide a complete answer to the original question