Surfactant-free silver nanofluids as liquid systems with neuromorphic potential
Nikitin, D.; Biliak, K.; Lemke, J.; Protsak, M.; Pleskunov, P.; Tosca, M.; Ali-Ogly, S.; Červenková, V.; Adejube, B.; Bajtošová, L.; Černochová, Zulfiya; Prokeš, J.; Křivka, I.; Biederman, H.; Faupel, F.; Vahl, A.; Choukourov, A.
2024 - English Neuromorphic engineering is a rapidly developing branch of science that aims to implement the unique attributes of biological neural networks in artificial devices. Most neuromorphic devices are based on the resistive switching effect, which involves changing the device’s conductivity in response to an external electric field. For instance, percolating nanoparticle (NP) networks produced by gas aggregation cluster sources (GAS) show collective spiking behavior in conductivity reminiscent of brain-like dynamics. Nevertheless, the problem of dynamic spatial reconfiguration in solid-state neuromorphic systems remains unsolved. Herein, novel nanofluids with resistive switching properties are proposed as neuromorphic media. They are produced by depositing silver NPs from GAS into vacuum-compatible liquids (paraffin, silicon oil, and PEG) without the use of surfactants or other chemicals. When the electric field is applied between two electrodes, the migration of NPs toward biased electrode is detected in all liquids. The electrophoretic nature of the NP movement was proved by means of ζ-potential measurements. Such movement led to the self-assembly of NPs in conductive paths connecting the electrodes and, as a result, to resistive switching. The electrical response was strongly dependent on the dielectric constant of the base liquid. The Ag-PEG nanofluid demonstrated the best switching performance reproducible during several tens of current-voltage cycles. The growth of flexible and reconfigurable conductive filaments in nanofluids makes them suitable media for potential realization of 3D neural networks. Keywords: nanofluid; gas aggregation cluster source; ζ-potential, electrophoresis Available at various institutes of the ASCR Surfactant-free silver nanofluids as liquid systems with neuromorphic potential

Neuromorphic engineering is a rapidly developing branch of science that aims to implement the unique attributes of biological neural networks in artificial devices. Most neuromorphic devices are based ...

Nikitin, D.; Biliak, K.; Lemke, J.; Protsak, M.; Pleskunov, P.; Tosca, M.; Ali-Ogly, S.; Červenková, V.; Adejube, B.; Bajtošová, L.; Černochová, Zulfiya; Prokeš, J.; Křivka, I.; Biederman, H.; Faupel, F.; Vahl, A.; Choukourov, A.
Ústav makromolekulární chemie, 2024

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 ...

Shapoval, Oleksandr; Větvička, D.; Kabešová, M.; Engstová, Hana; Horák, Daniel
Ústav makromolekulární chemie, 2024

Vliv biodegradabilní polyuretanové pěny na biocenózu a kalovou aktivitu v reaktorech simulující provoz domácích ČOV
Skleničková, Kateřina; Říhová Ambrožová, J.; Pečenka, M.; Halecký, M.; Beneš, Hynek
2022 - Czech Hydrophilic and fully aliphatic polyurethane (PUR) foam exhibiting a highly open cellular structure was used as a biodegradable biofilm carrier that would serve simultaneously as a nutrient source. A one-month laboratory testing in a reactor simulating domestic wastewater treatment plants was conducted based on chemical and hydrobiological analyses as well as evaluation of microorganism development and enzymatic activity. It was found that PUR foam can successfully serve as a carrier for microorganisms and simultaneously can be biodegraded when the supply of nutrition is limited. Byla navržena a připravena hydrofilní a plně alifatická biodegradabilní polyuretanová (PUR) pěna s otevřenou buněčnou strukturou, která byla následně použita jako nosič biofilmu a zdroj živin v reaktoru simulující domácí čistírnu odpadních vod. Na základě chemických, hydrobiologických analýz, vývoje mikroorganismů a enzymatických aktivit bylo zjištěno, že PUR pěna může úspěšně sloužit jako nosič pro mikroorganismy aktivovaného kalu a zároveň může být jimi postupně biodegradována při omezeném přísunu výživy aktivovaného kalu. Keywords: polyurethane foam; biofilm carriers; wastewater Available at various institutes of the ASCR Vliv biodegradabilní polyuretanové pěny na biocenózu a kalovou aktivitu v reaktorech simulující provoz domácích ČOV

Hydrophilic and fully aliphatic polyurethane (PUR) foam exhibiting a highly open cellular structure was used as a biodegradable biofilm carrier that would serve simultaneously as a nutrient source. A ...

Skleničková, Kateřina; Říhová Ambrožová, J.; Pečenka, M.; Halecký, M.; Beneš, Hynek
Ústav makromolekulární chemie, 2022

Degradation of polycaprolactone electrospun materials - methods of analysis
Havlíčková, K.; Řezanka, M.; Kobera, Libor; Kuželová Košťáková, E.; Lukáš, D.; Jenčová, V.
2021 - English Biodegradable electrospun materials are widely used for medical application. Polycaprolatone is polymer suitable for electrospinning technology and is very often used to create nanofibrous scaffolds for tissue engineering. The time to disintegration or biodegradation of such materials is very important here. However, testing is not entirely easy. It is not possible to create exactly body-like conditions in vitro. Moreover, it is not easy to find suitable analytical methods that would show exactly what happens in the nanofibrous polycaprolactone electrospun samples at certain stages of degradation, ie how the internal structure of decaying nanofibers changes. This paper describes the traditional use of methods for testing polycaprolatone nanofibers by enzymatically catalysed degradation. Morphological changes are studied using scanning electron microscope images. However, it also offers a non-traditional analysis of polycaprolactone electrospun materials using the ssNMR method. Keywords: electrospinning; nanofibers; enzymatic degradation Available at various institutes of the ASCR Degradation of polycaprolactone electrospun materials - methods of analysis

Biodegradable electrospun materials are widely used for medical application. Polycaprolatone is polymer suitable for electrospinning technology and is very often used to create nanofibrous scaffolds ...

Havlíčková, K.; Řezanka, M.; Kobera, Libor; Kuželová Košťáková, E.; Lukáš, D.; Jenčová, V.
Ústav makromolekulární chemie, 2021

Anticorrosive properties of silicotungstic acid and phosphotungstic heteropolyacid in the paint films
Nechvílová, K.; Kalendová, A.; Stejskal, Jaroslav
2016 - English The aim of this work was to provide an initial characterisation of heteropolyacids and examine their behaviour and properties as pigments in paints using different concentrations of the pigment and filler. Solvent-based epoxy-ester resin served as the binder. The paints were applied to steel and glass panels for mechanical and corrosion resistance testing. The organic coatings were exposed to a corrosive atmosphere with NaCl. This test was completed with electrochemical measurement. The parameters examined included the paint film's mechanical and anticorrosion efficiency. The environments in which the new coatings are most efficient were also sought. Keywords: heteropolyacids; epoxy-ester resin; organic coatings Fulltext is available at external website. Anticorrosive properties of silicotungstic acid and phosphotungstic heteropolyacid in the paint films

The aim of this work was to provide an initial characterisation of heteropolyacids and examine their behaviour and properties as pigments in paints using different concentrations of the pigment and ...

Nechvílová, K.; Kalendová, A.; Stejskal, Jaroslav
Ústav makromolekulární chemie, 2016

The influence of compression pressure on transport properties of polypyrrole nanotubes
Alekseeva, E.; Prokeš, J.; Bober, Patrycja; Stejskal, Jaroslav
2015 - English Keywords: conducting polymer; polypyrrole nanotubes Available at various institutes of the ASCR The influence of compression pressure on transport properties of polypyrrole nanotubes

Alekseeva, E.; Prokeš, J.; Bober, Patrycja; Stejskal, Jaroslav
Ústav makromolekulární chemie, 2015

Selected glasses of Ge-Se-Te system
Černošková, E.; Hejdová, M.; Černošek, Z.; Holubová, J.; Todorov, R.; Vlček, Milan
2015 - Czech Bulk glasses Ge30Se70-xTex for (x = 0, 10, 20) were prepared by direct synthesis. Thermal evaporation was used for preparation of thin films. The glass transition temperature of the bulk samples and decrease with increasing Te, but Tg of films with tellurium was not found. Crystallization temperature, Tc, for both bulk samples and films were close each to other. Comparing of Raman spectra - the corresponding Raman bands showed that medium-range order of bulks and thin films are partly different. 77Se MAS NMR of Ge30Se70 glass detected resonance of only Ge-Se-Ge (420 ppm, 98 %) and Se-Se-Se (837 ppm, 2 %), eliminating outrigger raft model and the structure of the studied glasses is probably close to Continuous Random Model. Objemové vzorky skel Ge30Se70-xTex pro x=0,10,20, byly připraveny přímou syntézou z prvků. Termickým napařováním byly připraveny i tenké filmy stejného složení. Byla studována struktura, termické vlastnosti i optické vlastnosti připravovaných prvků. Keywords: chalcogenide glasses; thin films; DSC Available at various institutes of the ASCR Selected glasses of Ge-Se-Te system

Bulk glasses Ge30Se70-xTex for (x = 0, 10, 20) were prepared by direct synthesis. Thermal evaporation was used for preparation of thin films. The glass transition temperature of the bulk samples and ...

Černošková, E.; Hejdová, M.; Černošek, Z.; Holubová, J.; Todorov, R.; Vlček, Milan
Ústav makromolekulární chemie, 2015

Ultrathin nanofibrous membranes with enhanced properties for transplantation of retinal pigment epithelial cells
Studenovská, Hana; Popelka, Štěpán; Abelová, Lucie; Riedel, Tomáš; Studený, P.; Straňák, Z.; Klíma, Jiří; Ardan, Taras; Dvořánková, B.; Rypáček, František
2015 - English Keywords: retinal tissue engineering; nanofibrous membrane; fibrin coating Available at various institutes of the ASCR Ultrathin nanofibrous membranes with enhanced properties for transplantation of retinal pigment epithelial cells

Studenovská, Hana; Popelka, Štěpán; Abelová, Lucie; Riedel, Tomáš; Studený, P.; Straňák, Z.; Klíma, Jiří; Ardan, Taras; Dvořánková, B.; Rypáček, František
Ústav makromolekulární chemie, 2015

Tradiční empirie a moderní přípravky v ochraně dřevěných konstrukcí proti ohni
Dušková-Smrčková, Miroslava; Osvald, A.; Šmíra, P.; Nasswettrová, A.; Chmelíková, Dana
2014 - Czech Keywords: wood; fire retardant of wood Available at various institutes of the ASCR Tradiční empirie a moderní přípravky v ochraně dřevěných konstrukcí proti ohni

Dušková-Smrčková, Miroslava; Osvald, A.; Šmíra, P.; Nasswettrová, A.; Chmelíková, Dana
Ústav makromolekulární chemie, 2014

Study of epoxy resin cered by derivates of hexachloro-cyclo-triphosphazene
Zárybnická, L.; Večeřa, M.; Bačovská, R.; Alberti, M.; Kincl, Miloslav
2014 - Czech The study deals with the curing of epoxy resins by using prepared derivatives of hexachloro-cyclo-triphosphazenes. Several types of derivatives hexachloro-cyclo-triphosphazenes were prepared with the selected amines using by the nucleophilic substitution. Considering the structure of the prepared derivatives, there is a presumption that the cured epoxy resin will show a higher thermal stability and flame retardant. Studie se zabývá vytvrzováním epoxidových pryskyřic pomocí připravených derivátů hexachloro-cyklo-triphosphazenů. Několik typů derivátů hexachloro-cyklo-triphosphazenů bylo připraveno s vybranými aminy za použití nukleofilní substituce. S ohledem na strukturu připravených derivátů, je možno se domnívat, že vytvrzené epoxidové pryskyřice budou vykazovat vyšší tepelnou stabilitu a odolnost vůči šíření plamene. Keywords: epoxy resin; hexachloro-cyclo-triphosphazenes; cure Available at various institutes of the ASCR Study of epoxy resin cered by derivates of hexachloro-cyclo-triphosphazene

The study deals with the curing of epoxy resins by using prepared derivatives of hexachloro-cyclo-triphosphazenes. Several types of derivatives hexachloro-cyclo-triphosphazenes were prepared with the ...

Zárybnická, L.; Večeřa, M.; Bačovská, R.; Alberti, M.; Kincl, Miloslav
Ústav makromolekulární chemie, 2014