No (3062)
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3062
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Preparation, Testing and Application of Amalgam Screen-Printed Electrodes
Josypčuk, Bohdan; Langmaier, Jan; Tvorynska, Sofiia
2021 - English
Silver amalgam screen-printed electrodes (AgA-SPEs) were designed, prepared, and tested for\nthe first time as perspective representatives among SPEs for measuring at high negative\npotentials. The precise coulometric preparation procedure for mercury deposition at the\nworking electrode surface of the commercial silver-SPE was developed. An optimal\nelectrolyzer construction for the mercury deposition, electrolyte composition, and electrolysis\nconditions were proposed. The maximum value of hydrogen overvoltage (-1979 ± 4 mV) was\nfound on AgA-SPE with 50% (w/w) of Hg content in 0.1 mol L-1 NaOH, which is more negative\nthan with the original silver-SPE for 387 mV (-1592 ± 12 mV).
Keywords:
electrochemistry; screen-printed electrodes; silver amalgam
Available on request at various institutes of the ASCR
Preparation, Testing and Application of Amalgam Screen-Printed Electrodes
Silver amalgam screen-printed electrodes (AgA-SPEs) were designed, prepared, and tested for\nthe first time as perspective representatives among SPEs for measuring at high negative\npotentials. The ...
Electrochemistry of Phospholes
Koláčná, Lucie; Liška, Alan; Ludvík, Jiří
2021 - English
Seventeen pentasubstituted phospholes with expected application in organic electronics were\nsynthesized and characterized electrochemically and by UV-vis spectra. Quantum chemical\ncalculations ofredox potentials and HOMO-LUMO energies were performed and experimental\nand theoretical data were successfully correlated. Tuning of redox properties can be achieved\nby combination of induction and resonance effects of substituents, extension / diminution of\nthe pi- delocalized system and by steric changes which affect intramolecular electron\ncommunication.
Keywords:
Pentasubstituted phospholes; Electrochemistry; UV-vis spectra
Available on request at various institutes of the ASCR
Electrochemistry of Phospholes
Seventeen pentasubstituted phospholes with expected application in organic electronics were\nsynthesized and characterized electrochemically and by UV-vis spectra. Quantum chemical\ncalculations ...
Electrochemical Characterization of Molecular Conductors Containing Redox Switching Element
Nováková Lachmanová, Štěpánka; Vavrek, František; Sebechlebská, Táňa; Šebera, Jakub; Kolivoška, Viliam; Lukášek, J.; Balzer, N.; Valášek, M.; Mayor, M.; Hromadová, Magdaléna
2021 - English
Electrochemical properties of new molecules containing tripodal anchor and redox switching\nelement have been studied by cyclic voltammetry and DFT quantum mechanical calculations.\nComparison of their redox properties with individual organometallic [Ru(terpy)2]2+t3+ and\n[Os(terpy)2]2+t3+ redox centers shows that covalently bonded tripodal anchor does not\ncompromise the reversibility of a redox process and has no effect on the stability of new\nmolecules. New molecular conductors have smaller HOMO-LUMO gap and both are oxidized\nat only slightly more positive potentials after tripodal substitution making them suitable for the\ndevelopment of molecular conductors with switching abilities.
Keywords:
Tripodal anchor; Cyclic voltammetry; DFT calculations
Available on request at various institutes of the ASCR
Electrochemical Characterization of Molecular Conductors Containing Redox Switching Element
Electrochemical properties of new molecules containing tripodal anchor and redox switching\nelement have been studied by cyclic voltammetry and DFT quantum mechanical calculations.\nComparison of ...
Electroplating of 3D Printed Electrodes for Selective Electrochemical Reduction of C02
Vaněčková, Eva; Bouša, Milan; Shestivska, Violetta; Kubišta, Jiří; Rathouský, Jiří; Sebechlebská, Táňa; Kolivoška, Viliam
2021 - English
In this work, computer assisted design and fused deposition modelling 3D printing are\nemployed to devise and manufacture electrodes from polylactic acid-carbon nanotube\nconductive composite. Electrodes are further modified by copper electroplating to prepare\ncatalysts for the electrochemical reduction of carbon dioxide. Scanning electron microscopy\nand energy dispersive X-ray analysis are used to inspect the surface morphology and chemical\ncomposition of obtained catalysts. Cyclovoltammetric investigations reveal that the copper\nelectroplating leads to the increase of electrode activity by three orders of magnitude.
Keywords:
3D printing; electrochemical reduction of carbon dioxide; electroplating
Available on request at various institutes of the ASCR
Electroplating of 3D Printed Electrodes for Selective Electrochemical Reduction of C02
In this work, computer assisted design and fused deposition modelling 3D printing are\nemployed to devise and manufacture electrodes from polylactic acid-carbon nanotube\nconductive composite. ...
Effect of elevated CO2 concentration and nitrogen nutrition on mais response to short-term high temperature and drought stress
Simor, J.; Klem, Karel
2021 - English
Within an experiment conducted in open top chambers in which two mais genotypes differing in stay-green trait were cultivated under elevated atmospheric CO2 concentration (EC) in comparison\nwith ambient CO2 concentration (AC), and in two contrast levels of nitrogen nutrition, the effect of acclimation to these factors on photosynthetic performance and water use efficiency, and subsequent response to short-term high temperature and drought stress was studied. Although EC improved water use efficiency, this effect did not alleviate the response to drought stress, and under some combinations of factors even led to a decrease in CO2 assimilation rate under drought stress. Differences in the stay- green trait between genotypes did not have a major effect on the response to high temperature and drought stress. Differences between genotypes were manifested mainly in the interaction with nitrogen nutrition, while in the Korynt genotype, non fertilised variants showed a lower response of CO2 assimilation rate to drought. Slight alleviating effect of higher nitrogen dose was found under EC conditions, while no nitrogen fertilisation rather increased drought resilience under AC conditions.
Keywords:
mais; elevated carbon dioxide; nitrogen nutrition; drought stress
Available at various institutes of the ASCR
Effect of elevated CO2 concentration and nitrogen nutrition on mais response to short-term high temperature and drought stress
Within an experiment conducted in open top chambers in which two mais genotypes differing in stay-green trait were cultivated under elevated atmospheric CO2 concentration (EC) in comparison\nwith ...
Enzymatic detoxification of cyanide using cyanide hydratases
Sedova, Anastasia; Rucká, Lenka; Glozlová, Michaela; Novotný, Petr; Martínková, Ludmila; Bojarová, Pavla
2021 - English
Cyanide, a strong chelator of metals in vital enzymes and proteins, is very toxic for most living organisms. Wastewaters from the mining, metallurgical and chemical industries contain significant concentrations of free cyanide. Though it can be largely eliminated by physicochemical methods, these processes may in turn lead to the formation of other waste. In addition, no effective methods have been found to neutralize cyanide spills coming from industrial accidents. The use of enzymes to remove cyanide is an attractive alternative, which is environmentally friendly and applicable to high cyanide concentrations. Cyanide hydratases (CynHs) are of considerable interest for the decomposition of hazardous cyanide wastes. Here we investigate the biochemical properties of new CynHs from Stereum hirsutum and Exidia glandulosa, it is of fundamental importance to preserve the enzyme activity at alkaline pH as cyanide waste is stored under these conditions.
Keywords:
free cyanide; cyanide hydratase; cyanide spills; cyanide waste
Available at various institutes of the ASCR
Enzymatic detoxification of cyanide using cyanide hydratases
Cyanide, a strong chelator of metals in vital enzymes and proteins, is very toxic for most living organisms. Wastewaters from the mining, metallurgical and chemical industries contain significant ...
Comparison of the Covalent Laccase Immobilization at Amino- and Carboxylfunctionalized Mesoporous Silica, Glassy Carbon, and Graphite Powders using Different Coupling Agents for Optimal Biosensor Preparation
Tvorynska, Sofiia; Barek, J.; Josypčuk, Bohdan
2021 - English
In order to find the most suitable immobilization protocol, a comparison of three strategies\nbased on the application of –NH2 and –COOH functionalized supports with the different\nactivation agents (glutaraldehyde and carbodiimide) have been conducted for the covalent\nenzyme (laccase) attachment. Two kinds of the supports, namely mesoporous silica (SBA−15,\nMCM−41) and carbonaceous (glassy carbon, graphite) powders, have been used. It was found\nthat a biosensor consisted of tubular detector of silver solid amalgam as a working electrode\nand the enzymatic mini-reactor with laccase covalently attached to glutaraldehyde activated\n–NH2 functionalized MCM−41 shows the best results regarding sensitivity and stability for\ndopamine detection.
Keywords:
Covalent enzyme immobilization; Support surface functionalization; Laccase
Available on request at various institutes of the ASCR
Comparison of the Covalent Laccase Immobilization at Amino- and Carboxylfunctionalized Mesoporous Silica, Glassy Carbon, and Graphite Powders using Different Coupling Agents for Optimal Biosensor Preparation
In order to find the most suitable immobilization protocol, a comparison of three strategies\nbased on the application of –NH2 and –COOH functionalized supports with the different\nactivation agents ...
EPR/UV-VIS-NIR Spectroelectrochemical Examination of the Association Properties of Thienoacene-Bridged Tetrathiafulvalenes Supported by DFT Calculations
Lušpai, Karol; Rapta, P.; Zalibera, M.; Darvasiová, D.; Lukeš, V.
2021 - English
This work was focused on the EPR/UV-VIS-NIR spectroelectrochemical examination of\nassociation properties of radical cations electrochemically produced from tetrathiafulvalene\n(TTF) derivatives, in relation to the molecular structure, mainly the number and orientation of\nthiophene rings in the spacer between fulvalene redox centers. Results from EPR/UV-VIS-NIR\nspectroelectrochemistry were supported by DFT calculations.
Keywords:
Tetrathiafulvalene; EPR/UV-VIS-NIR spectroelectrochemistry; Cyclic voltammetry
Available on request at various institutes of the ASCR
EPR/UV-VIS-NIR Spectroelectrochemical Examination of the Association Properties of Thienoacene-Bridged Tetrathiafulvalenes Supported by DFT Calculations
This work was focused on the EPR/UV-VIS-NIR spectroelectrochemical examination of\nassociation properties of radical cations electrochemically produced from tetrathiafulvalene\n(TTF) derivatives, in ...
UV-Vis and IR Spectroelectrocbemistry of Copper Complexes and Bioactive Compounds
Sokolová, Romana; Obluková, Michaela; Sýs, M.; Mikysek, T.; Wantulok, J.; Nycz, J. E.; Degano, I.
2021 - English
The interpretation of the change of absorption spectrum of an oxidized and reduced molecule\nrecorded during the electron transfer is an efficient tool for the determination of oxidation or\nreduction mechanism. This technique provides the information about the electroactive\nchromophore and is performed in two regimes of electrochemical measurement, cyclic\nvoltammetry and chronoamperometry, respectively. This approach was successfully applied to\nstudy the fundamental electrochemical behavior of recently synthesized copper complexes\nproviding biomimetic activity, ofpolyphenolic bioactive compounds, and also for the reduction\nof halogenated phenanthrolines. The identification of redox products was done by\nchromatographic techniques as HPLC-DAD and HPLC-ESI-MS/MS.
Keywords:
Copper complexes; Catechol; spectroelectrochemistry
Available on request at various institutes of the ASCR
UV-Vis and IR Spectroelectrocbemistry of Copper Complexes and Bioactive Compounds
The interpretation of the change of absorption spectrum of an oxidized and reduced molecule\nrecorded during the electron transfer is an efficient tool for the determination of oxidation or\nreduction ...
Estimation of winter wheat yield using machine learning from airborne hyperspectral data
Švik, Marian; Pikl, Miroslav; Janoutová, Růžena; Veselá, Barbora; Slezák, Lukáš; Klem, Karel; Homolová, Lucie
2021 - English
Methods based on optical remote sensing allow nowadays to assess crop conditions over larger areas. The assessment of crop conditions and potential estimation of crop yields in the early growth\nstages can help farmers to better target their management practice such as application of fertilizers. In this study we analysed airborne hyperspectral images acquired several times during the growing season over two experimental sites in the Czech Republic (Ivanovice and Lukavec). The field experiments on winter wheat included 12 levels of fertilisation (combination of organic and mineral fertilisers). Such an experiment design and the possibility of combining the data from two sites together increased the variability in our wheat yield dataset, which varied between 2.8 and 10.0 t/ha. Further, we used a machine learning method – namely gaussian process regression from the ARTMO toolbox to train two variants of models: a) combining the spectral data from both sites and from the multiple acquisition days and b) combining the spectral data from both sites for individual acquisition days.The results showed that it was feasible to predict wheat yield already at the beginning of April with R2 > 0.85. This promising result, however, requires more thorough validation and therefore we plan to include more data from other sites in the next steps.
Keywords:
hyperspectral; machine learning; remote sensing; winter wheat; yield
Available at various institutes of the ASCR
Estimation of winter wheat yield using machine learning from airborne hyperspectral data
Methods based on optical remote sensing allow nowadays to assess crop conditions over larger areas. The assessment of crop conditions and potential estimation of crop yields in the early ...
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