No (9942)
Yes (1923)
Number of found documents:
11865
Published from
to
Vertical Gradients of Atmospheric Aerosols Chemical Composition
Kovářík, Jiří
2024 - English
Concentration of chemical species chosen as markers for AA source apportionment are evaluated with regard to atmospheric conditions, seasonal and daily cycles and compared between the two heights. This work adds to the current state of general knowledge about AACC.
Keywords:
vertical gradients; chemical composition; atmospheric aerosols
Available in a digital repository NRGL
Vertical Gradients of Atmospheric Aerosols Chemical Composition
Concentration of chemical species chosen as markers for AA source apportionment are evaluated with regard to atmospheric conditions, seasonal and daily cycles and compared between the two heights. ...
Cultivation of Limnospira Maxima and Utilization of its Fresh Biomass in Human Nutrition
Vásquez, Claudia
2024 - English
This project aims to fill this gap by presenting new insights into its consumption as an alternative to dried spirulina and offering recommendations\nfor safe storage.
Keywords:
Limnospira maxima; dietary supplements; bioengineering
Available in a digital repository NRGL
Cultivation of Limnospira Maxima and Utilization of its Fresh Biomass in Human Nutrition
This project aims to fill this gap by presenting new insights into its consumption as an alternative to dried spirulina and offering recommendations\nfor safe storage.
Verification of the dynamic properties of a new model turbine wheel with free blades
Voronova, Evgeniya; Procházka, Pavel; Maturkanič, Dušan; Mekhalfia, Mohammed Lamine; Hodboď, Robert
2024 - English
The paper describes a new experimental model of turbine wheel with free blades. Verification tests were carried out using a Doppler laser vibrometer, with a focus on the equipment parameters under various conditions. The measurements were performed in the Laboratory of Rotational Laser Vibrometry originated at the Institute of Thermomechanics AS CR, v.v.i.
Keywords:
natural frequencies; vibration; blade; laser; turbine
Available at various institutes of the ASCR
Verification of the dynamic properties of a new model turbine wheel with free blades
The paper describes a new experimental model of turbine wheel with free blades. Verification tests were carried out using a Doppler laser vibrometer, with a focus on the equipment parameters under ...
Reaction Mechanisms of Psychoactive Compounds
Sokolová, Romana; Beneš, Marek; Jiroušková, Eliška; Degano, I.
2024 - English
The reaction mechanism of selected new psychoactive substances (NPS) 4-methylpentedrone and 2-(((4-ethyl-2,5-dimethoxyphenethyl)amino)methyl)phenol was investigated based on their\nelectrochemical and spectroelectrochemical properties. Both drugs were examined by means of cyclic voltammetry using diagnostic parameters for particular reaction schemes, UV/Vis, and IR\nspectroelectrochemistry. Since water participates in the redox mechanism of both studied compounds, the reaction mechanism was studied under a controlled amount of water in an\nacetonitrile environment.
Keywords:
oxidation; reduction; IR spectrochemistry
Available on request at various institutes of the ASCR
Reaction Mechanisms of Psychoactive Compounds
The reaction mechanism of selected new psychoactive substances (NPS) 4-methylpentedrone and 2-(((4-ethyl-2,5-dimethoxyphenethyl)amino)methyl)phenol was investigated based on their\nelectrochemical and ...
Spectroelectrochemical Devices for Monitoring of Intermediates and Products on Carbonbased Composite Electrodes
Vaněčková, Eva; Šikula, M.; Hrdlička, Vojtěch; Sebechlebská, Táňa; Kolivoška, Viliam
2024 - English
Spectroelectrochemistry (SEC), as an interdisciplinary field, provides us with more comprehensive information about electroactive molecules involved in charge transfer reactions. Commercially\navailable SEC cells most often have an incorporated platinum working electrode, which can limit the range of the usable potential window and, in addition, can complicate the analysis due to the\nabsorption phenomenon. In this work, we designed and manufactured two types of custom-made SEC cells employing optically transparent carbon-based working electrodes for UV-Vis monitoring of reactants and electrogenerated intermediates and products. The first SEC cell is entirely manufactured by 3D printing using fused deposition modeling (FDM) by combining optically transparent (PET) and electrically conductive (PLA-CB) filaments. The second SEC cell employs pencil graphite (PG) rods as the working electrode (PGE) and its body is manually assembled from quartz slides. The functionality of the FDM 3D printed SEC cell and manually assembled quartz SEC cell were verified by cyclic voltammetry with in situ UV-Vis spectroscopic absorption monitoring of ruthenium(III) acetylacetonate (Ru(ac)3) redox-active probe dissolved in an aqueous or non-aqueous deaerated solvent, respectively. Both presented cells enable complete redox reversible conversion and strictly oxygen-free conditions.
Keywords:
pencil graphite electrode; spectroelectrochemistry; 3D printed electrode
Available on request at various institutes of the ASCR
Spectroelectrochemical Devices for Monitoring of Intermediates and Products on Carbonbased Composite Electrodes
Spectroelectrochemistry (SEC), as an interdisciplinary field, provides us with more comprehensive information about electroactive molecules involved in charge transfer reactions. ...
Numerical evaluation of mass-diffusive compressible fluids flows models
Bodnár, Tomáš; Fraunié, P.
2024 - English
This contribution presents first numerical tests of some recently published alternative models for solution of viscous compressible and nearly incompressible models. All models are solved by high resolution compact finite difference scheme with strong stability preserving RungeKutta time stepping. The two simple but challenging computational test cases are presented, based on the double-periodic shear layer and the Kelvin-Helmholtz instability. The obtained time-dependent flow fields are showing pronounced shear and vorticity layers being resolved by the standard as well as by the new mass-diffusive modified models. The preliminary results show that the new models are viable alternative to the well established classical models.
Keywords:
compressible Navier-Stokes; nearly incompressible flow; mass diffusion; compact finite-difference
Available in digital repository of the ASCR
Numerical evaluation of mass-diffusive compressible fluids flows models
This contribution presents first numerical tests of some recently published alternative models for solution of viscous compressible and nearly incompressible models. All models are solved by high ...
Motion of fluids in the moving domain
Nečasová, Šárka
2024 - English
It is a survay paper where the problem of the existence of weak solutions of compressible barotropic solutions in a moving bounded domain is studied.
Keywords:
compressible fluid; moving domain; weak solutions
Available in digital repository of the ASCR
Motion of fluids in the moving domain
It is a survay paper where the problem of the existence of weak solutions of compressible barotropic solutions in a moving bounded domain is studied.
Temoporfin-conjugated upconversion nanoparticles for NIR-induced photodynamic therapy of pancreatic cancer
Shapoval, Oleksandr; Větvička, D.; Kabešová, M.; Engstová, Hana; Horák, Daniel
2024 - English
Photodynamic therapy (PDT), a clinically approved cancer treatment strategy, has the potential to cure pancreatic cancer with minimal side effects. PDT primarily uses visible wavelengths to directly activate hydrophobic photosensitizers, which may be insufficient for deep-seated cancer cells in clinical practice due to poor penetration. Upconversion nanoparticles (UCNPs) serve as an indirect excitation source to activate photosensitizers (PSs) in the NIR region, overcoming the limitations of molecular PSs such as hydrophobicity, non-specificity, and excitation in the UV/Vis region. Here, monodisperse upconversion NaYF4:Yb3+, Er3+, Fe2+ nanoparticles (UCNPs) have been surface-engineered with poly(methyl vinyl ether-alt-maleic acid) (PMVEMA) and temoporfin (mTHPC), a clinically used PDT prodrug, for near-infrared (NIR) light-triggered PDT of pancreatic cancer. The incorporation of Fe2+ ions into the particles increased the fluorescence intensity in the red region matching the activation wavelength of mTHPC. Covalent binding of mTHPC to the surface of UCNP@PMVEMA particles provided colloidally stable conjugates enabling generation of singlet oxygen. In vitro cytotoxicity and photodynamic activity of the particles were evaluated using INS-1E rat insulinoma and Capan-2 and PANC-01 human pancreatic adenocarcinoma cell lines. The PDT efficacy of UCNP@PMVEMA-mTHPC conjugates after irradiation with 980 nm NIR light was tested in vivo in a pilot study on Capan-2 human pancreatic adenocarcinoma growing subcutaneously in athymic nude mice. The intratumoral administration of the nanoconjugates significantly hindered tumor growth and demonstrated promising PDT efficacy against human pancreatic cancer.
Keywords:
photodynamic therapy; temoporfin; upconversion nanoparticles
Available in digital repository of the ASCR
Temoporfin-conjugated upconversion nanoparticles for NIR-induced photodynamic therapy of pancreatic cancer
Photodynamic therapy (PDT), a clinically approved cancer treatment strategy, has the potential to cure pancreatic cancer with minimal side effects. PDT primarily uses visible wavelengths to directly ...
PROPERTIES OF NANOCRYSTALLINE FE-NI PARTICLES PREPARED BY THERMAL REDUCTION OF OXALATE PRECURSORS
Švábenská, Eva; Roupcová, Pavla; Havlíček, Lubomír; Schneeweiss, Oldřich
2024 - English
Recent technological advancements require development of cost-effective and high-performance magnets \nwhich ideally do not contain rare earth metals or noble metals. The promising candidates are Fe-Ni-based \nalloys, in particular, the Fe50Ni50 L10 phase (tetrataenite), which has a great perspective for producing hard \nmagnetic materials. Our study explores a promising method for preparing nanoparticles of Fe-Ni alloy from an \niron-nickel oxalate precursor. The coprecipitation method was employed to prepare oxalate precursors, \nfollowed by controlled thermal decomposition in a reducing hydrogen atmosphere. The morphology and \nproperties of the resulting particles were analysed using scanning electron microscopy (SEM) coupled with \nenergy dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD), Mössbauer spectroscopy (MS), and \nmagnetic measurements.\nThe SEM analysis revealed that the particles have approximately cube-shaped unit cell morphology with a\nsize in a range of 1 - 2 μm. Upon annealing, the samples contain multiple phases with varying Fe-Ni content.\nMagnetic measurements confirmed the formation of magnetically suitable Fe-Ni phases in the samples after \nannealing. Mössbauer spectroscopy emerged as a highly effective method for characterizing individual phases \nof the Fe-Ni system.
Keywords:
Magnetic materials; thermal decomposition; Mössbauer spectroscopy
Available at various institutes of the ASCR
PROPERTIES OF NANOCRYSTALLINE FE-NI PARTICLES PREPARED BY THERMAL REDUCTION OF OXALATE PRECURSORS
Recent technological advancements require development of cost-effective and high-performance magnets \nwhich ideally do not contain rare earth metals or noble metals. The promising candidates are ...
EFFECT OF OXIDE DISPERSION ON ELECTRIC CONDUCTIVITY OF ROTARY SWAGED POWDER-BASED COPPER COMPOSITES
Kunčická, Lenka; Benč, Marek; Kačor, P.; Marek, M.
2024 - English
Copper is a very popular electro-conductive material, however, the mechanical properties of pure Cu are low. They can be typically improved by (micro)alloying, or via structure modifications introduced by optimized deformation and thermomechanical treatments. Designing a Cu-based composite, possibly strengthened by a dispersion of fine oxides, is another way how to favourably improve the strength properties of Cu. In this study, we performed mechanical alloying of a Cu powder with a powder of Al2O3 oxide, which is known to have strengthening effects on metallic materials. After mixing, we sealed the powder mixture into evacuated tubular Cu containers (i.e. cans). As for the consolidation procedure, we applied direct consolidation of the canned powders via the intensive plastic deformation method of rotary swaging, performed under warm conditions. Subsequently, we subjected the swaged conductors to measurements of electric conductivity and detailed structure observations. The results revealed that the applied swaging ratio was sufficient to fully consolidate the canned powders as the final conductor was unrecognizable from a cast alloy from the viewpoints of visual and structure assessment. In other words, the structure did not exhibit any voids or remnants of unconsolidated powder particles. The observed fine grains with homogeneous dispersion of Al2O3 oxide particles provided improvement of the mechanical properties, as proven by microhardness measurements. Moreover, the electric properties remained favourable.
Keywords:
mechanical-properties; extrusion; Copper; oxide dispersion; electric conductivity; rotary swaging; microstructure
Available at various institutes of the ASCR
EFFECT OF OXIDE DISPERSION ON ELECTRIC CONDUCTIVITY OF ROTARY SWAGED POWDER-BASED COPPER COMPOSITES
Copper is a very popular electro-conductive material, however, the mechanical properties of pure Cu are low. They can be typically improved by (micro)alloying, or via structure modifications ...
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