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Time-lapse monitoring of cell mechanical properties
Přibyl, J. ; Rotrekl, V. ; Pešl, M. ; Jelínková, Š. ; Kratochvílová, Irena
Atomic force microscopy (AFM) is a highly sensitive non-invasive surface method able to provide insight into cells' mechanical parameters. Membrane and sub-membrane development, as well as internal cellular properties, can be monitored. The stiffness of cells is a fundamental phenomenon that reflects changes in cell physiology. More importantly, changes in cell mechanical properties are also often found to be closely associated with various disease conditions. Cell mechanics are mainly dependent on cytoskeletal architecture. The development of cryopreserved cells' mechanical properties (stiffness) after thawing was studied using AFM.\n
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Polyvinylpyrrolidone coating for nanodiamond stabilization in saline solution and silver nanoparticle decoration
Kolářová, Kateřina ; Miliaieva, Daria ; Stehlík, Štěpán
This work presents use of polyvinylpyrrolidone (PVP) for multipurpose coating of oxidized high-pressure high-temperature and detonation nanodiamonds. This simple way of nanodiamonds surface modification aims to improve their colloidal stability in biological environments and reduce their proneness to agglomeration. PVP immobilized on nanodiamond surface also provides for nanodiamond-supported AgNPs preparation by in situ synthesis using AgNO3 as a metallic nanoparticles precursor. Dynamic light scattering (DLS) and UV-vis spectroscopy were used for evaluation of nanoparticles size distribution and dispersibility in water and after exposition of nanoparticles in saline solution. Images acquired by scanning electron microscopy and transmission electron microscope validate the possibility of binding ~ 10 nm AgNPs to nanodiamonds surface.
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Radical-based tuning the surface functionality of MXene
Olshtrem, A. ; Chertopalov, Sergii ; Guselnikova, O. ; Švorčík, V. ; Lyutakov, O.
The family of MAX phases and their derivative MXenes are continuously growing in terms of both crystalline and composition varieties. MXenes are a new family of two-dimensional (2D) transition metal carbides, carbonitrides and nitrides, with a general formula Mn+1AXn, where n = 1–3, M denotes a transition metal, A is an element such as aluminum or silicon, and X is either carbon or nitrogen. Considering the various elemental composition possibilities, surface functional tunability, various magnetic orders, and large spin–orbit coupling, MXene can truly be considered as multifunctional materials that can be used to realize highly correlated phenomena.
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Toxic responses in human lung epithelial cells (BEAS-2B) exposed to particulate matter exhaust emissions from gasoline and biogasoline
Závodná, Táňa ; Líbalová, Helena ; Vrbová, Kristýna ; Sikorová, Jitka ; Vojtíšek-Lom, M. ; Beránek, V. ; Pechout, M. ; Kléma, J. ; Cigánek, M. ; Machala, M. ; Neča, J. ; Rössner ml., Pavel ; Topinka, Jan
Motor vehicle emissions substantially contribute to air pollution worldwide and cause serious health problems. While the deleterious effects of diesel exhaust particulate matter (PM) have been widely studied, much less attention is paid to toxicity of PM emitted by gasoline engines although they also produce considerable amount of PM. The primary objective of this research was to assess toxic potencies of exhaust PM released by conventional gasoline engine fueled with neat gasoline (EU) or gasoline-ethanol blend (15% ethanol, v/v, E15). Despite a similar particle mass (mu g PM/kg fuel) produced by both fuels, PM emitted by E15 contained higher amount of harmful polycyclic aromatic hydrocarbons (PAH) as suggested by chemical analysis. To examine the toxicity of organic PM constituents, human lung BEAS-2B cells were exposed for 4h and 24h to a subtoxic dose of E0 and E15 PM organic extracts. We used genome scale transcriptomic analysis to characterize the toxic response and to identify modulated biological process and pathways. Whereas 4h exposure to both PM extracts resulted in modulation of similar genes and pathways related to lipid and steroid metabolism, activation of PPAR alpha, oxidative stress and immune response, 24h exposure was more specific for each extract, although both induced expression of PAH-metabolic enzymes, modulated metabolism of lipids or activated PPAR alpha, E15 additionally deregulated variety of other pathways. Overall, the PM mass produced by both fuels was similar, however, higher PAH content in E15 PM organic extract may have contributed to more extensive toxic response particularly after 24h exposure in BEAS-2B cells.
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Effect of the substrate crystalline orientation on the surface morphology and boron incorporation into epitaxial diamond layers
Voves, J. ; Pošta, A. ; Davydova, Marina ; Laposa, A. ; Povolný, V. ; Hazdra, P. ; Lambert, Nicolas ; Sedláková, Silvia ; Mortet, Vincent
Epitaxial growth of diamond is critically important for the fabrication of diamond-based electronic devices. The emerging study of the epitaxial diamond growth on the (113) vicinal surfaces evidences highly needed high growth rates and low structural defects concentrations with both p- and n-type doping. In this work, we compare the morphology and dopant concentration incorporation of heavily boron-doped (113) epitaxial diamond layers with conventionally studied (100) and (111) epitaxial layers. Epitaxial layers were grown using resonance cavity Microwave Plasma Enhanced Chemical Vapor Deposition (MWPECVD) system. The surface morphology of epitaxial layers was studied by optical microscopy and atomic force microscopy, whereas the boron incorporation homogeneity was determined by Raman spectroscopy mapping.
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Nanospray processing of silver nanoparticles for formation of dried deposits
Týčová, Anna ; Jonas, Vladimír ; Přikryl, Jan ; Kotzianová, A. ; Velebný, V. ; Foret, František
Nanospray transfers liquid into an aerosol via electrostatic forces created between an emitter and a counter electrode. Herein, we present compact laboratory-made instrumentation for nanospray-processing of silver colloid. The instrumentation is based on the pressurized polysulfone chamber fixing a disposable vial with an immersed platinum electrode and a long fused silica capillary supplying the sprayed liquid to the emitter. The combination of low flow rates (70 nL/min) with a sharp emitter, fabricated on a 3D printed grinding station, resulted in a fine aerosol. The low volume of released droplets allowed full evaporation of water during their flight towards the counter electrode without any need for drying gas or the addition of volatile solvents. The constructed device was successfully used for the deposition of water-free silver colloid without any requirement of its pretreatment. The deposition of completely dried nanoparticles on planar substrates eliminated undesirable coffee ring effect and deposits of increased homogeneity could be obtained. Electron microscopy confirmed no significant changes in the character of nanospray-processed nanoparticles. Finally, we also investigated several approaches for the improvement of the surface density of nanoparticles on the substrate at preserved time scale.
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IMPOSING BIAXIAL STRAIN ON 2D LAYERED MATERIALS BY LIQUID-INDUCED SWELLING OF SUPPORTING POLYMER
Sampathkumar, Krishna ; Pekárek, J. ; Frank, Otakar
2D layered materials promise to revolutionize the field of electronics, photonics, optoelectronics, energy storage, and sensing, etc. 2D materials have exceptional mechanical properties, with critical elongation >10%. Employing the strain to manipulate the electronic structure of these 2D materials could lead to further improvement of their implementation in many aspects. The ease of manipulation of their electronic structure can be one of the critical factors for their utilization in photonic devices. Apart from the strain, which decreases (increases) the bandgap energy at the rate of similar to 100 meV under 1% of biaxial tension (compression), also the layer number causes bandgap energy change of, e.g., 0.5 eV between bulk (1.3 eV) and monolayer MoS2 (1.8 eV). In our work, we focus on using the swelling behavior of PMMA/SU8 polymer in methanol to impose the strain on 2D layered materials. In the first trials, we have shown that it is possible to reach a strain gradient from 0 to similar to 0.5% of biaxial strain via simple swelling of polymer substrates, both for graphene [1] and transition metal di-chalcogenides (TMDC) like MoS2. Raman spectroscopy was used to probe the lattice strain in the materials through measuring changes of vibrational frequencies, and photoluminescence was used to probe the strain-induced bandgap character and energy in TMDC at room temperature. The surface corrugation of the 2D material after the soaking was recorded with the help of atomic force microscope (AFM).
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Patterning of conductive nano-layers on garnet
Chlumská, Jana ; Lalinský, Ondřej ; Matějka, Milan ; Krátký, Stanislav ; Kolařík, Vladimír
Synthetic crystalline materials of the garnet group are used as scintillators in scanning electron microscopy. If a thick conductive layer is applied on the garnet surface, slower electrons don't have enough energy to pass through this relatively thick conductive layer on the scintillator surface. Therefore, either thinner conductive layer or appropriate patterning of the thicker layer has to be used. Within this contribution we study the patterning process of such conductive nano-layer. Resolution of the patterning process is of high interest. Two approaches are compared: direct writing electron beam lithography and mask projection UV lithography.
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