Thes event is cancelled due to Coronavirus. It is to be announced if the event will be organized on some other day.
Third Science Rendezvous - conference with short introductory talks about scientific topics followed at UCT Prague. The event takes place on Thursday 12th of March from 3 pm in Lecture hall AII.
|Paula Da Silva Tourinho||Microplastic fibers as a vector of silver nanoparticles: adsorption mechanisms and ecotoxicity|
|Seyedmehdi Hosseini||Preparation and characterization of AlNiCo poly-quasicrystal by mechanical alloying and spark plasma sintering process|
|Carmen Mayorga Martinez||Two-dimensional Materials for Biomedical and Environmental Control Sensors|
|Nicolai Nikishkin||Novel Redox-active Cyclophanes of Pillar-, Calix- and Mixed-type Topology|
|Gabriela Ruphuy Chan||Yeast-derived Particles for Drug Delivery|
|Aiym Tleuova||Temperature-responsive safer formulation of fungicide|
|Magdalena Urbaniak||Plant secondary metabolites and microbial degradation of structurally related xenobiotics|
|Alexandr Zubov||Discrete Element Modelling of Colloidal Suspensions|
|Alena Michalcová||Self-healing Alloys|
|Prasad Talluri||High-performance Membranes for Separation of Biofuels|
Paula Da Silva Tourinho
Plastic pollution is far and wide. All environments, from urban areas to the most isolated places, are contaminated by small plastic fragments known as microplastics. One main type of microplastic is the synthetic fibers released from textiles. These microplastic fibers are released from the washing machines in our home, reaching aquatic and terrestrial habitats. Once in the environment, microplastic fibers can adsorb other chemical pollutants, acting as a carrier for these pollutants. We aimed at investigating the adsorption of silver nanoparticles to polyester microplastic fibers and its toxic effects on aquatic and terrestrial organisms. Silver nanoparticles were chosen as the model pollutant for being vastly used in the textile industry due to its antimicrobial properties.
Preparation and characterization of AlNiCo poly-quasicrystal by mechanical alloying and spark plasma sintering process
Quasicrystals (QCs) are categorized as advanced materials with forbidden rotational symmetry in their atomic arrangement. Due to this peculiar arrangement, they show a unique set of properties at elevated temperatures such as good oxidation resistance, temperature dependence of Young's modulus, and brittle-to-ductile transition. During the plastic deformation at elevated temperatures, the yield strength of QCs reduces with increasing the temperature, and work softening occurs upon the yield point. In this study, ultrafine-grained Al71Ni14.5Co14.5 quasicrystal alloy was developed by short-term mechanical alloying and spark plasma sintering process. The properties of the material exhibited a positive temperature dependence during the compression test up to 600 °C, so that both strength and strain enhanced by 68.7 and 71.7%, respectively. In contrast to other quasicrystals, work hardening was also observed during the test at intermediate temperatures. To move towards the prospective materials applicable at elevated temperatures, this astounding behavior was analyzed by an investigation on the microstructure and fracture surface of the samples using TEM and SEM.
Heteroatom-bridged cyclophanes represent the recently introduced class of macrocycles with unique chemical and physical properties compared to the classic analogues. Thus, introduction of bridging heteroatoms into a ‘classic’ scaffold brings in the higher conformational flexibility, yet unknown reactivity patterns of a macrocycle as wells as leads into appearance of additional sites for non-covalent interactions within its crystalline framework. At the same time, the incorporation of redox-active units within a macrocyclic scaffold enables modulation of the macrocycles electronic properties and allows to study various macrocycle’s intermolecular interactions with electrochemical methods.
In this presentation the synthesis of sulfur-bridged cyclophanes based on Michael addition methodology will be covered in coup with the redox, binding and structural properties of the obtained macrocycles.
Gabriela Ruphuy Chan
Yeast is one of the most commonly used ingredients in the food industry, but less commonly known is its potential use in drug delivery. The so-called yeast-derived beta glucan particles (GPs) are obtained from the cell wall of Saccharomyces cerevisiae (baker’s yeast), and because they are hollow and porous microparticles, they are suitable candidates as drug carriers. The mechanisms in which yeast glucan particles can potentially improve oral bioavailability of drugs will be briefly explained and discussed.
To date fungicides are irreplaceable tool for combatting phytopathogenic fungi and for keeping high efficacy of agriculture. However, most of fungicides have several disadvantages, such as low water solubility, degradation under environmental impact, ecotoxicity, necessity of big amounts and repeated spraying. To solve these issues microencapsulation technique can be implemented. This allows to control and target the release, to eliminate active ingredient (AI) from aggressive environment, improve properties of AI, protect environment against toxicity of AI, etc. In this work fungicide pyraclostrobin was encapsulated to control its release via temperature change. In order to employ such temperature-responsive ability to fungicide formulation a phase change material (octadecane) was used as a core of microcapsule. Pyraclostrobin-loaded microcapsules were characterized using SEM, DLS, FTIR techniques, stimuli-responsivity was tested by means of in vitro tests with pathogenic culture (Fungal strain of Pyrenophora teres - CPPF-453) grown in Petri dishes. PyrMCs showed excellent antifungal effect above the melting point of octadecane (~28°C) and weaker effect below 28°C. Research results demonstrate a potential of temperature-responsive microencapsulated fungicide for successful utilization in agriculture.
Rhizoremediation is one of the most effective processes of pollutants removal due to existing interactions in the rhizosphere between plant exudates, including plant secondary metabolites (PSMs), and microorganisms.
Although there is a considerable body of evidence that PSMs can cause changes in microbial community composition and stimulate microbial degradation of xenobiotics, the mechanisms of action on the molecular level (e.g. degradative gene induction) in relation to their chemical structure have not been fully understood yet. With this in mind, our aim is to acquire new knowledge on the role of PSMs in the microbial degradation of structurally related xenobiotics and in the expression level of the corresponding degradative genes.
Discrete Element Method (DEM) is a popular method for modelling dynamics of granular media and powders materials. In this contribution we demonstrate how DEM can be utilized for prediction of complex phenomena arising in colloidal suspensions, e.g. particle coagulation, fouling, as well as estimation of suspension properties like viscosity and viscoelasticity.