Time filter

Source Type

Ústí nad Labem, Czech Republic

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.

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 | 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.

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.

Discover hidden collaborations