University of Jan Evangelista Purkyne

Ústí nad Labem, Czech Republic

University of Jan Evangelista Purkyne

Ústí nad Labem, Czech Republic
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Komloova M.,Charles University | Musilek K.,University of Jan Evangelista Purkyne | Dolezal M.,Charles University | Gunn-Moore F.,University of St. Andrews | Kuca K.,University of Jan Evangelista Purkyne
Current Medicinal Chemistry | Year: 2010

Myasthenia gravis is a rare autoimmune neuromuscular junction disorder mainly caused by antibodies being targeted against the muscle acetylcholine receptors (AChRs). The loss of AChRs leads to a defect in neuromuscular transmission resulting in muscle weakness and fatigue. Although once an often fatal illness, Myasthenia gravis can now be well managed with relatively safe and effective treatments. However, the severe myasthenic cases associated with thymus tumors remain often fatal exception in the management of the disease. The early treatment includes the use of acetylcholinesterase inhibitors (AChEI) which enhance neuromuscular transmission. To ensure a peripheral effect, charged molecules are used, particularly quaternary ammonium salts. The structure of AChEIs has been continuously modified to obtain the optimal ratio between AChE inhibition and potential side-effects. This review summarizes progress in the use of quaternary compounds as AChE inhibitors in vitro with respect to their structure and inhibitory ability. Namely, carbamic acid esters, piperidinium and pyridinium salts, bisquaternary pyridinium salts and heterogeneous quaternary inhibitors are all discussed. Among data found in the literature, many compounds have shown promising inhibition of AChE when compared to commercial standards (pyridostigmine, neostigmine). Besides a promising inhibitory ability, selectivity for AChE versus butyrylcholinesterase (BChE) for the most potent compounds (sub-nanomolar IC50) was also identified. © 2010 Bentham Science Publishers Ltd.

Musilek K.,University of Jan Evangelista Purkyne | Dolezal M.,Charles University | Gunn-Moore F.,University of St. Andrews | Kuca K.,University of Jan Evangelista Purkyne
Medicinal Research Reviews | Year: 2011

Organophosphate pesticides (OPPs; e.g. chlorpyrifos, diazinon, paraoxon) are a wide and heterogeneous group of organophosphorus compounds. Their biological activity of inhibiting acetylcholinesterase (AChE) or butyrylcholinesterase (BChE) ranks them as life endangering agents. The necessary treatment after OPP exposure involves the use of parasympatolytics (e.g. atropine), oxime reactivators (e.g. obidoxime), and anticonvulsive drugs (e.g. diazepam). Therefore, the reactivators of AChE are essential compounds in the treatment of OPP intoxications. Commercial AChE reactivators (e.g. pralidoxime, HI-6, obidoxime, trimedoxime, methoxime) were originally developed for other members of the organophosphate family, such as nerve agents (e.g. sarin, soman, tabun, VX). Pralidoxime, HI-6, and methoxime were found to be weak reactivators of OPP-inhibited AChE. Obidoxime and trimedoxime showed satisfactory reactivation against various OPPs with minor toxicity issues. During the last two decades, the treatment of OPP exposure has become more widely discussed because of growing agricultural production, industrialization, and harmful social issues (e.g. suicides). In this review is the summarized design, evaluation, and structure-activity relationship studies of recently produced AChE reactivators. Since pralidoxime, over 300 oximes have been produced or tested against OPP poisoning, and several novel compounds show very promising abilities as comparable (or higher) to commercial oximes. Some of these are highlighted for their further testing of OPP exposure and, additionally, the main structure-activity relationship of AChE reactivators against OPP is discussed. © 2009 Wiley Periodicals, Inc.

Svoboda K.,Czech Institute of Chemical Process Fundamentals | Svoboda K.,University of Jan Evangelista Purkyne | Pohorely M.,Czech Institute of Chemical Process Fundamentals | Pohorely M.,Institute of Chemical Technology Prague | And 6 more authors.
Fuel Processing Technology | Year: 2012

Polish bituminous coal, German brown (subbituminous) coal and rapeseed oil were selected for preparation of coal-oil slurry (COS) and coal-oil in water slurry (COWS) with content of coal about 50 mass%. Laboratory, electrically heated gasifier with fluidized bed (FB) of sand particles was used for the coal slurries gasification with steam-O 2 and CO 2-O 2 mixtures (ER = 0.19-0.23) at temperatures between 800 and 925 °C. FB gasification with mixtures of O 2/CO 2 (CO 2/dry fuel mass ratio 1-2.4) can generate producer gas with LHV values about 8-10 MJ/m 3. The heating value of the dry, N 2-free producer gas from CO 2-O 2 gasification is lower in comparison with gasification by steam-O 2 mixtures at comparable conditions. The heating value of the producer gas is influenced by a relatively high content of methane, ethylene and BTX compounds. The yield of heavier tar compounds (excluding BTX) is high, exceeding 20 g tar/kg of dry German coal based COS and exceeding 36 g/kg of fuel for Polish coal based COS. Cold gas efficiency is higher for fuel gas from gasification of COS based on the German, subbituminous coal. FB gasification (ER ≈ 0.2) of the COWS prepared from the Polish coal (contents of coal, water and oil 47, 40 and 12 mass% respectively) reduces tar yield approximately to an half (related to gasification of the corresponding COS slurry), but simultaneously moderately reduces the heating value (LHV) of the dry, nitrogen free producer gas. © 2011 Elsevier B.V. All rights reserved.

Janos P.,University of Jan Evangelista Purkyne | Ederer J.,University of Jan Evangelista Purkyne | Dosek M.,University of Jan Evangelista Purkyne
Nova Biotechnologica et Chimica | Year: 2014

Reactive forms of cerium oxide were prepared by a thermal decomposition of various precursors, namely carbonates, oxalates and citrates, commercially available nanocrystalline cerium oxide (nanoceria) was involved in the study for comparison. Scanning electron microscopy (SEM) and x-ray diffraction analysis (XRD) were used to examine the morphology and crystallinity of the samples, respectively, whereas the Brunauer-Emmett-Teller (BET) method of nitrogen adsorption was used to determine surface areas. Interactions of cerium oxide with some phosphorus-containing compounds were investigated. Some of the examined samples, especially those prepared by annealing from carbonate precursors, exhibited an outstanding ability to destroy highly toxic organophosphates, such as pesticides (parathion methyl), or nerve agents (soman, VX). There were identified some relations between the degradation efficiency of cerium oxides and their crystallinity. It was also shown that cerium oxide is able to destroy one of widely used flame retardants - triphenyl phosphate. A phosphatase-mimetic activity of various cerium oxides was examined with the aid of a standardized phosphatase test. © University of SS. Cyril and Methodius.

Janos P.,University of Jan Evangelista Purkyne | Vavrova J.,University of Jan Evangelista Purkyne | Herzogova L.,University of Jan Evangelista Purkyne | Pilarova V.,University of Jan Evangelista Purkyne
Geoderma | Year: 2010

Six kinds of amendments were added to contaminated soil with the goal to alter the mobility of heavy metals and to modify potential environmental impacts. The following amendments were used at doses ranging from 1 to 5%: two kinds of young brown coals (lignite, oxihumolite) with a high content of humic acids, two commercially available derivatives of humic acids (potassium humate and iron humate), and two inorganic materials (fly ash and natural zeolite). Leachability of heavy metals (Cd, Cu, Pb, and Zn) from untreated and amended soils was studied with the aid of a standardized sequential extraction test (BCR test). Cd was present predominantly in the readily mobilizable (acid extractable) form in the soil; its mobility was reduced effectively after an addition of potassium humate. Cu, Pb and Zn were bound more strongly to the soil matrix. The mobility of Cu was reduced after an addition of inorganic amendments (zeolite and fly ash), whereas potassium humate was effective in the immobilization of Pb. Most of Zn (more than 60%) was bound rather strongly in the residual fraction and its mobility was affected only slightly by the presence of amendments at the concentration levels used in this work. Nevertheless, it was shown that even relatively low doses of amendments may cause a significant re-distribution of heavy metals in soil, which could be employed in the soil remediation. © 2010 Elsevier B.V.

Janos P.,University of Jan Evangelista Purkyne | Kopecka A.,University of Jan Evangelista Purkyne | Hejda S.,University of Jan Evangelista Purkyne
Desalination | Year: 2011

Iron humate (IH) produced as a waste by-product during an industrial manufacture of humic substances from young brown coals was tested as a new cost-effective sorbent for the removal of inorganic phosphorus from waters. The sorption capacity approaching ca. 10mgPg-1 was comparable with that reported for other non-conventional sorbents, and was nearly independent on pH in a slightly acidic to neutral working range of the sorbent. It was found that the phosphate binding to IH is a relatively slow process requiring several days to attain equilibrium. The kinetics of the phosphate sorption was described by a recently introduced modified pseudo-n-order (MPnO) rate equation. Extraction tests showed that a major part of phosphorus in IH is associated strongly with iron-containing compounds or humate matrix of the sorbent and may be hardly liberated into the environment. Only minor fraction of phosphorus is readily mobilizable by leaching with water. © 2010 Elsevier B.V.

Ritschelova I.,University of Jan Evangelista Purkyne
Environmental Earth Sciences | Year: 2011

The possibility of cancellation of the territorial ecological limits for brown coal mining in North Bohemian Region (Podkrushnohori coal field) was a subject of wide speculation during the whole year 2005. The territorial ecological restrictions for individual mines and dumps determine the limits which should not be exceeded during strip mining and waste dumping activities. These limits are determined to protect the regional communities against the coalface front expansion and to respect the sanitary zones between the outskirts of the villages and the prospective utmost edges of the mine. These limits were established after the "Velvet Revolution" in the Czech Republic of 1991. Their aim was to prevent the further devastation of the landscape and exhaustion of the nonrenewable natural recourses in the region. The speculations about the cancellation of the limits arouse on the basis of refinement of the State Energy Policy of the Czech Republic. The discussion about the national fuel and energy balance, about the possibilities and hazards of the nuclear energy and renewable power sources use and about the power intensity of the Czech economy intensified at the same time. The authors of the paper discuss the possible environmental impacts of the cancellation of eco-limits, its influence on the economic situation in the Czech Republic and in the region itself, as well as social consequences of the respective decision. © Springer-Verlag Berlin Heidelberg 2011.

Janos P.,University of Jan Evangelista Purkyne | Hladik T.,University of Jan Evangelista Purkyne | Kormunda M.,University of Jan Evangelista Purkyne | Ederer J.,University of Jan Evangelista Purkyne | Stastny M.,University of Jan Evangelista Purkyne
Advances in Materials Science and Engineering | Year: 2014

Cerium oxide belongs to the most important heterogeneous catalysts, but its applicability as so-called reactive sorbent for the degradation of toxic chemicals was only recently discovered. For these purposes, cerium oxide is prepared by precipitation of insoluble cerium salts (carbonates) with a subsequent thermal decomposition. Properties of cerium oxide prepared from the carbonate precursor are strongly affected by the temperature during the calcination. Main physicochemical properties of cerium oxide (specific surface area, crystallinity, and surface chemistry) were examined in dependence on the calcination temperature. As the adsorptive properties of CeO2 are undoubtedly of great importance in the abovementioned applications, the adsorption ability was studied using an azo dye Acid Orange 7 (AO7) as a model compound. The highest sorption efficiency towards AO7 exhibited sorbents prepared at temperatures below 700°C, which was attributed mainly to the presence of hydroxyl groups on the oxide surface. A strong correlation was found between an adsorption efficiency of cerium oxides and their degradation efficiency for organophosphate pesticide parathion methyl. The >Ce-OH groups on the sorbent surface are responsible for the dye binding by the surface-complexation mechanism, and probably also for the nucleophilic cleavage of the P-O-aryl bond in the pesticide molecule. © 2014 Pavel Janoš et al.

Janos P.,University of Jan Evangelista Purkyne | Kormunda M.,University of Jan Evangelista Purkyne | Novak F.,Academy of Sciences of the Czech Republic | Zivotsky O.,VSB - Technical University of Ostrava | And 2 more authors.
Reactive and Functional Polymers | Year: 2013

The magnetic sorbents with various contents of humic acids (ca. 6.6-15.5%) were prepared by a simple co-precipitation procedure from Fe2+/ Fe3+ salts and a commercially available alkaline humate concentrate. The sorbents were able to remove heavy metal cations (Cu2+) from waters with the sorption capacity ranging from 0.006 to 0.25 mmol/g in dependence on the content of humic acids. An ability to remove some organic compounds (triazine and organophosphate pesticides) was also demonstrated. In both cases, the presence of humic acids in the sorbents plays a crucial role in the sorption process-whereas the sorption of metal cations was attributed to the presence of acidic functional groups, the sorption of (less polar) organic compounds was attributed to the presence of glassy-state polymeric domains in the iron-humate matrix. The iron-humate sorbents were effective also in the removal of inorganic phosphorus (phosphate anions) from water. In this case, however, the removal efficiency decreased with increasing content of humic acids in the sorbent. Although the saturation magnetization decreased proportionally with increasing content of humic acids, it remained still sufficiently high for all the examined sorbents to facilitate their effective separation in magnetic field. © 2012 Elsevier Ltd. All rights reserved.

PubMed | University of Jan Evangelista Purkyne and Academy of Sciences of the Czech Republic
Type: | Journal: Journal of colloid and interface science | Year: 2016

The uniform Sn-doped CuO nanoparticles were synthesized by a simple solution method at a low temperature. The prepared samples were investigated by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), electron microscopy techniques (HRSEM, HRTEM, SAED, STEM and EDS elemental mapping), atomic force microscopy (AFM), UV/Vis spectroscopy, nitrogen physisorption (BET) and by evaluation of the catalytic activity on the degradation of Rhodamine B. The tin doping had a considerable influence on the morphology of CuO. The gradual narrowing of the particles morphology in the crystallographic [010] direction was observed with increasing the dopant concentration. The plate-like, rectangularsquare and rod-like CuO nanoparticles were obtained. The mechanism of a crystal growth of CuO associated with doping is proposed. The tin doping also affected the structural and optical properties of CuO. Increasing the amount of a dopant led to a red-shift of a band gap from 1.33 to 1.18eV. The incorporation of tin into the structure of copper oxide was confirmed by XRD and distribution of tin mapped by EDS analysis. The good catalytic properties of the as-prepared doped material were demonstrated by the enhanced catalytic removal of Rhodamine B in the presence of H2O2. The undoped CuO nanosheets reached only 24% efficiency in the removal of Rhodamine B within two hours. The best result exhibited CuO_050Sn sample containing 4at.% of tin and the degradation of Rhodamine B reached 99% within the same time. We have demonstrated a simple, scalable process for the preparation of catalytically very active Sn-doped CuO nanoparticles with varying properties.

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