Publications by authors named "Daniela Placha"

27 Publications

  • Page 1 of 1

Colloidal stability of phytosynthesised gold nanoparticles and their catalytic effects for nerve agent degradation.

Sci Rep 2021 Feb 18;11(1):4071. Epub 2021 Feb 18.

Nanotechnology Centre, CEET, VŠB - Technical University of Ostrava, 17. listopadu 2172/15, 708 00, Ostrava, Czech Republic.

Herein, Tilia sp. bract leachate was used as the reducing agent for Au nanoparticles (Au NPs) phytosynthesis. The colloidal properties of the prepared Au NPs were determined to confirm their stability over time, and the NPs were then used as active catalysts in soman nerve agent degradation. The Au NPs characterisation, reproducibility and stability studies were performed under transmission electron microscopy, ultraviolet visible spectroscopy and with ζ-potential measurements. The reaction kinetics was detected by gas chromatography coupled with mass spectrometry detector and solid-phase micro-extraction to confirm the Au NPs applicability in soman hydrolysis. The 'green' phytosynthetic formation of colloidal crystalline Au NPs with dominant quasi-spherical shape and 55 ± 10 nm diameter was successfully achieved, and there were no significant differences in morphology, ζ-potential or absorbance values observed during the 5-week period. This verified the prepared colloids' long-term stability. The soman nerve agent was degraded to non-toxic substances within 24 h, with 0.2156 h reaction rate constant. These results confirmed bio-nanotechnology's great potential in preparation of stable and functional nanocatalysts for degradation of hazardous substances, including chemical warfare agents.
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http://dx.doi.org/10.1038/s41598-021-83460-1DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7892814PMC
February 2021

Chronic Inflammatory Diseases, Anti-Inflammatory Agents and Their Delivery Nanosystems.

Pharmaceutics 2021 Jan 6;13(1). Epub 2021 Jan 6.

Department of Analytical Chemistry, Faculty of Natural Sciences, Comenius University, Ilkovicova 6, 842 15 Bratislava, Slovakia.

Inflammatory diseases, whether caused by excessive stress on certain tissues/parts of the body or arising from infections accompanying autoimmune or secondary diseases, have become a problem, especially in the Western world today. Whether these are inflammations of visceral organs, joints, bones, or the like, they are always a physiological reaction of the body, which always tries to eradicate noxious agents and restore tissue homeostasis. Unfortunately, this often results in damage, often irreversible, to the affected tissues. Nevertheless, these inflammatory reactions of the body are the results of excessive stress, strain, and the generally unhealthy environment, in which the people of Western civilization live. The pathophysiology and pathobiochemistry of inflammatory/autoimmune processes are being studied in deep detail, and pharmaceutical companies are constantly developing new drugs that modulate/suppress inflammatory responses and endogenous pro-inflammatory agents. In addition to new specifically targeted drugs for a variety of pro-inflammatory agents, a strategy can be found for the use of older drugs, which are formulated into special nanodrug delivery systems with targeted distribution and often modified release. This contribution summarizes the current state of research and development of nanoformulated anti-inflammatory agents from both conventional drug classes and experimental drugs or dietary supplements used to alleviate inflammatory reactions.
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http://dx.doi.org/10.3390/pharmaceutics13010064DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7825503PMC
January 2021

Chemical Hydrogels Bearing Thiazolium Groups with a Broad Spectrum of Antimicrobial Behavior.

Polymers (Basel) 2020 Nov 29;12(12). Epub 2020 Nov 29.

Instituto de Ciencia y Tecnología de Polímeros (ICTP-CSIC), C/Juan de la Cierva 3, 28006 Madrid, Spain.

Several hydrogels based on 2-hydroxyethyl methacrylate and a methacrylic monomer containing a thiazole group in its lateral chain have been prepared by thermal polymerization at 60 °C in water solution varying the chemical composition of the gels. The posterior quaternization of the thiazole groups with methyl iodine has rendered positively charged hydrogels with potential antimicrobial activity. This modification has been structurally characterized by infrared spectroscopy, whereas the thermal stability of all hydrogels has been studied by thermal degradation in inert atmosphere. The swelling behavior in distilled water and the rheology of the different hydrogels have been analyzed as a function of 2-(4-methylthiazol-5-yl)ethyl methacrylate (MTA) monomer content as well as its methylation. Finally, the active character of hydrogels against Gram-positive and Gram-negative bacteria and fungi has been evaluated, revealing excellent antimicrobial activity against all tested microorganisms. The methylated hydrogels could be used as potential materials for wound healing or contact lens applications.
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http://dx.doi.org/10.3390/polym12122853DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7761506PMC
November 2020

Antibacterial Character of Cationic Polymers Attached to Carbon-Based Nanomaterials.

Nanomaterials (Basel) 2020 Jun 22;10(6). Epub 2020 Jun 22.

Instituto de Ciencia y Tecnología de Polímeros (ICTP-CSIC), C/Juan de la Cierva 3, 28006 Madrid, Spain.

The preparation of hybrid polymeric systems based on carbon derivatives with a cationic polymer is described. The polymer used is a copolymer of a quaternizable methacrylic monomer with another dopamine-based monomer capable of anchoring to carbon compounds. Graphene oxide and graphene as well as hybrid polymeric systems were widely characterized by infrared, Raman and photoemission X-ray spectroscopies, electron scanning microscopy, zeta potential and thermal degradation. These allowed confirming the attachment of copolymer onto carbonaceous materials. Besides, the antimicrobial activity of hybrid polymeric systems was tested against Gram positive and and Gram negative and bacteria. The results showed the antibacterial character of these hybrid systems.
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http://dx.doi.org/10.3390/nano10061218DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7353121PMC
June 2020

Biodegradation of Reactive Orange 16 azo dye by simultaneous action of Pleurotus ostreatus and the yeast Candida zeylanoides.

Folia Microbiol (Praha) 2020 Aug 22;65(4):629-638. Epub 2020 Jan 22.

Department of Biology and Ecology, Faculty of Science, University of Ostrava, Chittussiho 10, 710 00, Slezská Ostrava, Czech Republic.

The purpose was to investigate a simultaneous biodegradation of the recalcitrant monoazo dye Reactive Orange 16 (RO16) in a mixed culture consisting of a biofilm of Pleurotus ostreatus-colonizing polyamide carrier and a suspension of the yeast Candida zeylanoides to see their biological interactions and possible synergistic action during degradation. Decolorization in the mixed culture was more effective than in the fungal monoculture, the respective decolorizations reaching 87.5% and 70% on day 11. The proliferation of yeast was reduced compared with the C. zeylanoides monoculture but enabled the yeast to participate in decolorization. The interaction of P. ostreatus with the yeast resulted in a gradual decrease of fungal manganese-dependent peroxidase (MnP) and laccase activities. Gas chromatography-mass spectrometry (GC-MS) analysis of the degradation products brought evidence that P. ostreatus split the dye molecule asymmetrically to provide 4-(ethenylsulfonyl) benzene whose concentration was much decreased in the mixed culture suggesting its increased metabolization in the presence of the yeast. In contrast, C. zeylanoides split the azo bond symmetrically producing the metabolites 4-(ethenylsulfonyl) aniline and α-hydroxybenzenepropanoic acid. Those metabolites were rapidly degraded in the mixed culture. A novel aspect is represented by the evidence of a mutual cooperative action of the fungal and yeast microorganisms in the mixed culture resulting in rapid decolorization and degradation of the dye.
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http://dx.doi.org/10.1007/s12223-019-00767-3DOI Listing
August 2020

Graphenic Materials for Biomedical Applications.

Nanomaterials (Basel) 2019 Dec 11;9(12). Epub 2019 Dec 11.

Department of Analytical Chemistry, Faculty of Natural Sciences, Comenius University, Ilkovicova 6, 842 15 Bratislava, Slovakia.

Graphene-based nanomaterials have been intensively studied for their properties, modifications, and application potential. Biomedical applications are one of the main directions of research in this field. This review summarizes the research results which were obtained in the last two years (2017-2019), especially those related to drug/gene/protein delivery systems and materials with antimicrobial properties. Due to the large number of studies in the area of carbon nanomaterials, attention here is focused only on 2D structures, i.e. graphene, graphene oxide, and reduced graphene oxide.
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http://dx.doi.org/10.3390/nano9121758DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6956396PMC
December 2019

Biocompatible Polymer Materials with Antimicrobial Properties for Preparation of Stents.

Nanomaterials (Basel) 2019 Oct 31;9(11). Epub 2019 Oct 31.

Nanotechnology Centre, VŠB-Technical University of Ostrava, 17. listopadu 15, 708 00 Ostrava-Poruba, Czech Republic.

Biodegradable polymers are promising materials for use in medical applications such as stents. Their properties are comparable to commercially available resistant metal and polymeric stents, which have several major problems, such as stent migration and stent clogging due to microbial biofilm. Consequently, conventional stents have to be removed operatively from the patient's body, which presents a number of complications and can also endanger the patient's life. Biodegradable stents disintegrate into basic substances that decompose in the human body, and no surgery is required. This review focuses on the specific use of stents in the human body, the problems of microbial biofilm, and possibilities of preventing microbial growth by modifying polymers with antimicrobial agents.
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http://dx.doi.org/10.3390/nano9111548DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6915381PMC
October 2019

Adsorption of nerve agent simulants onto vermiculite structure: Experiments and modelling.

J Hazard Mater 2020 01 17;382:121001. Epub 2019 Aug 17.

National Institute for NBC Protection, Kamenná 71, Milín 262 31, Czech Republic.

Chemical warfare agents are still a threat to humanity despite the existence of a ban on their production and use. There are many new materials that have been experimentally verified to be effective in degrading and eliminating various chemical warfare agents; however, clay minerals still remain very effective, environmentally friendly and not expensive. Vermiculites modified with hexadecylpyridinium, hexadecyltrimethylammonium and tetramethylammonium cations were used for static sorption of vapours of two simulants of nerve agents: dimethyl methyl phosphonate and diethyl ethyl phosphonate. The materials before and after sorption were characterized using infrared spectroscopy, X-ray diffraction and carbon phase analysis. The breakthrough time and capture of simulants were measured using dynamic sorption test. Molecular modelling was used to confirm the experimental results and provide a deeper insight into the structure of the materials and sorption processes.
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http://dx.doi.org/10.1016/j.jhazmat.2019.121001DOI Listing
January 2020

Improvement of Glibenclamide Water Solubility by Nanoparticle Preparation.

J Nanosci Nanotechnol 2019 May;19(5):3031-3034

Department of Pharmaceutical Chemistry, Faculty of Pharmacy, Comenius University, Odbojarov 10, 832 32 Bratislava, Slovakia.

Glibenclamide, a drug used for the treatment of type 2 diabetes, belongs to Class II of Biopharmaceutical Classification System. It is a highly permeable, but poorly water-soluble drug. Nanoparticles of glibenclamide were prepared by an emulsion solvent evaporation method using dichloromethane as a solvent of glibenclamide and 3% (w/w) aqueous solution of carboxymethyl dextran sodium salt as a stabilizer, which was found as optimal. A solubility test comparing the water solubility of glibenclamide bulk and nanoparticles confirmed the improved (2-fold higher) solubility of glibenclamide nanoparticles (0.045 g/ml) compared with bulk (0.024 g/ml).
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http://dx.doi.org/10.1166/jnn.2019.15876DOI Listing
May 2019

Silver/Chitosan Antimicrobial Nanocomposites Coating for Medical Devices: Comparison of Nanofiller Effect Prepared via Chemical Reduction and Biosynthesis.

J Nanosci Nanotechnol 2019 May;19(5):2938-2942

Nanotechnology Centre, VŠB - Technical University of Ostrava, 17. listopadu 15, 708 33 Ostrava-Poruba, Czech Republic.

Medical devices have an essential part in healthcare system in recent years, such as usage of heart valves, several types of stents and implants devices in patients. However, bacterial infection of medical devices causes critical issues for patients due to attachment of bacteria and formation of biofilm onto the medical devices. Therefore, finding an effective antibacterial coating to prevent biofilm formation and infection is our goal. In this study, we developed silver/chitosan nanocomposites for antimicrobial coating system by chemical and green methods using sodium borohydride and linden extract, respectively. Silver is known as a strong inorganic antimicrobial agent to kill bacteria by inactivating enzymes and dysfunction bacterial cell membranes. By immobilizing silver nanoparticles on chitosan biopolymer can prevent agglomeration of nanoparticles, besides it can improve the biocompatibility. We characterized properties of our silver chitosan nanocomposites samples using particle size distribution, ultraviolet-visible spectroscopy, X-ray diffraction analysis and scanning electron microscopy. Effective antimicrobial film preventing biofilm formation on medical devices was designed. Antimicrobial testing confirmed antimicrobial properties however variable for each type of nanosilver.
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http://dx.doi.org/10.1166/jnn.2019.15863DOI Listing
May 2019

Micronization of Ibuprofen Particles Using Supercritical Fluid Technology.

J Nanosci Nanotechnol 2019 May;19(5):2814-2820

Nanotechnology Centre, VŠB-Technical University of Ostrava, 17. listopadu 15, 708 33 Ostrava-Poruba, Czech Republic.

Most of drugs are only slightly soluble in the circulatory system of the human body. This reduces the efficiency of their use and that is why new ways how to increase their solubility are investigated. One way to improve the solubility of the drug is to reduce its particle size. Conventional techniques such as crushing or grinding usually do not guarantee a narrow particle size distribution, which is required for pharmaceuticals. Application of supercritical fluids, especially of supercritical CO₂, seems to be convenient method for the preparation of pharmaceuticals submicron particles or nanoparticles. The method enables the preparation of particles in a narrow size distribution and at the same time it does not leave any unwanted residues of solvents or other chemicals. The aim of this work is the micronization of ibuprofen particles using the supercritical fluid and characterization of formed products. The micronization of the particles was done using commercially available device Spe-ed SFE-4 in rapid expansion of supercritical solution mode. The applied temperatures and pressures were 308.15 K and 313.15 K and 200, 250 and 300 bar. The prepared particles were characterized using methods of X-ray diffraction, infrared spectroscopy, particle size distribution, scanning electron microscopy and tests of dissolution and permeability. Mean particles size was reduced from 180 m (original ibuprofen) to 2.8-7.3 m of the processed samples. The dissolution test confirmed better solubility and the permeability of newly formed particles improved.
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http://dx.doi.org/10.1166/jnn.2019.15874DOI Listing
May 2019

Phytosynthesis of Au and Au/ZrO₂ bi-Phasic System Nanoparticles with Evaluation of Their Colloidal Stability.

J Nanosci Nanotechnol 2019 May;19(5):2807-2813

Nanotechnology Centre, VŠB - Technical University of Ostrava, 17. listopadu 15/2172, Ostrava 70833, Czech Republic.

Due to its easy availability, preparation, handling and non-toxic nature, horsetail extract was chosen as a reducing, stabilizing and functionalizing agent for Au and bi-phasic Au/ZrO₂ nanoparticle phytosynthesis-inorganic nanoparticle synthesis mediated by plant extract. We studied Au and bi-phasic Au/ZrO₂ nanoparticles in colloids by various physical-chemical and analytical methods over 5 weeks. Dynamic Light Scattering and Scanning Transmission Electron Microscopy compared core and hydrodynamic diameters of nanoparticles. -potential measurement indirectly determined nanoparticles stability in liquid medium. Ultraviolet-Visible Spectroscopy characterized basic absorbance maxima for both Au and the bi-phasic Au/ZrO₂ system. Finally, total metal concentration was determined using Inductively Coupled Plasma Mass Spectrometry. -potential measurements proved satisfactory stability of both Au (-13.4 to -17 mV) and Au/ZrO₂ nanoparticles (-14.1 to -17.5 mV) over the experimental period. Scanning Transmission Electron Microscopy with Selected Area Diffraction analysis confirmed nanoparticles crystalline nature, and we determined 24 nm and 40 nm core nanogold diameters in Au and Au/ZrO₂ nanoparticle colloids. Dynamic light scattering analysis confirmed the dichotomy between particle sizes in liquid medium in the hundreds of nanometers measured, and long-term measurements confirmed reasonable colloid stability-a paramount parameter for potential nanoparticles applications; especially in heterogeneous catalysis.
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http://dx.doi.org/10.1166/jnn.2019.15851DOI Listing
May 2019

Effect of Milling and Annealing on Carbon-Silver System.

J Nanosci Nanotechnol 2019 May;19(5):2770-2774

Leibniz-Institut für Festkörper- und Werkstoffforschung, Dresden, P.O. Box 270116, D-01171 Dresden, Germany.

Mechanical treatment of graphite silver mixture followed by heat treatment showed morphology and structure changes of both components. Silver is being distributed over graphite flakes randomly with higher concentration on the edges and nanometric size, which was observed using scanning and transmission electron microscopy. The annealing temperature 1300 °C is higher than melting temperature of silver (961.8 °C) and base on phase diagram C-Ag (C. L. Chen, et al., 96, 253104 .) silver is being transferred from liquid phase to solid phase at rapid cooling, which is giving various crystallinity.
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http://dx.doi.org/10.1166/jnn.2019.15869DOI Listing
May 2019

Organovermiculite as Regenerable Nanostructured Adsorbent for Treatment of Heavily Polluted Waste Water from Coke Industry.

J Nanosci Nanotechnol 2019 May;19(5):2567-2574

Nanotechnology Centre, VŠB-Technical University of Ostrava, 17. listopadu 15, Ostrava-Poruba 708 33, Czech Republic.

Organically modified vermiculites can be used as nanostructured adsorbents of organic compounds from waters or gaseous phases similarly as organically modified smectites or bentonites. There is a large amount of research data focused on adsorption properties of organoclays, however only a little information is about their post-sorption treatment. This work is focused on study of two possible ways of subsequent processing of organovermiculite after its use as sorbent for heavily polluted waste water. At first, the vermiculite modified with hexadecylpyridinium ions was used in batch static sorption against phenol ammonium water from the coke industry to get highly contaminated sorption material, especially containing organic hydrocarbons and their derivatives. The sorbent is known to have excellent sorption properties; however ecotoxicological characteristics of original material showed that sorbent had hazardous properties even before its utilization. For that reason, it was necessary to design a post-sorption treatment. Two possible methods of treatment were investigated, specifically solvent treatment (with dichloromethane) and thermal treatment (thermodesorption) at temperatures of 300 and 1100 °C, respectively. The treated materials were studied using infrared spectroscopy, X-ray diffraction and carbon phase analyses. The solvent treatment confirmed that it is possible to reuse modified vermiculite as adsorbent several times, although adsorption capacity after each extraction decreases. The thermal treatment at 300 °C was not sufficient to remove all organic compounds from the vermiculite structure; however at 1100 °C the only presence of magnesium silicate, magnesium aluminate and ferric oxide confirmed the formation of an inert material convenient for an environmentally harmless disposal of used adsorbent.
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http://dx.doi.org/10.1166/jnn.2019.15861DOI Listing
May 2019

Polylactide Composites Suitable for Medical Devices.

J Nanosci Nanotechnol 2019 May;19(5):2506-2513

Nanotechnology Centre, VŠB - Technical University of Ostrava, 17. listopadu 15, 708 33 Ostrava-Poruba, Czech Republic.

Biodegradable polymeric materials with antimicrobial surfaces could be a suitable alternative for production of medical devices, especially if they are prepared in form of composites containing functional matter. Their greatest advantage is that they do not need to be removed from patient's body and simultaneously they can prevent growth of biofilm. In this work, polymeric films of polylactide acid with biosynthetically prepared silver nanoparticles, commercial multiwall carbon nanotubes and organovermiculite with hexadecyltrimethylammonium bromide in various concentrations were prepared to get polylactide composite with antibacterial properties. The dispersibility of filler in matrix was one of the key issues to be controlled in nanocomposite. Using several analytical techniques and observing morphology of prepared composite it was found that best results provide organovermiculite filler. For the tests of functionality antimicrobial tests were performed.
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http://dx.doi.org/10.1166/jnn.2019.15871DOI Listing
May 2019

From biotechnology principles to functional and low-cost metallic bionanocatalysts.

Biotechnol Adv 2019 Jan - Feb;37(1):154-176. Epub 2018 Nov 24.

Nanotechnology Centre, VŠB - Technical University of Ostrava, 17. listopadu 15/2172, Ostrava, Czech Republic; ENET Centre, VŠB - Technical University of Ostrava, 17. listopadu 15/2172, Ostrava, Czech Republic.

Chemical, physical and mechanical methods of nanomaterial preparation are still regarded as mainstream methods, and the scientific community continues to search for new ways of nanomaterial preparation. The major objective of this review is to highlight the advantages of using green chemistry and bionanotechnology in the preparation of functional low-cost catalysts. Bionanotechnology employs biological principles and processes connected with bio-phase participation in both design and development of nano-structures and nano-materials, and the biosynthesis of metallic nanoparticles is becoming even more popular due to; (i) economic and ecologic effectiveness, (ii) simple one-step nanoparticle formation, stabilisation and biomass support and (iii) the possibility of bio-waste valorisation. Although it is quite difficult to determine the precise mechanisms in particular biosynthesis and research is performed with some risk in all trial and error experiments, there is also the incentive of understanding the exact mechanisms involved. This enables further optimisation of bionanoparticle preparation and increases their application potential. Moreover, it is very important in bionanotechnological procedures to ensure repeatability of the methods related to the recognised reaction mechanisms. This review, therefore, summarises the current state of nanoparticle biosynthesis. It then demonstrates the application of biosynthesised metallic nanoparticles in heterogeneous catalysis by identifying the many examples where bionanocatalysts have been successfully applied in model reactions. These describe the degradation of organic dyes, the reduction of aromatic nitro compounds, dehalogenation of chlorinated aromatic compounds, reduction of Cr(VI) and the synthesis of important commercial chemicals. To ensure sustainability, it is important to focus on nanomaterials that are capable of maintaining the important green chemistry principles directly from design inception to ultimate application.
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http://dx.doi.org/10.1016/j.biotechadv.2018.11.012DOI Listing
July 2019

Effects of binder choice in converter and blast furnace sludge briquette preparation: Environmental and practical implications.

Waste Manag 2018 Sep 17;79:30-37. Epub 2018 Jul 17.

Nanotechnology Centre, VŠB-Technical University of Ostrava, 17. listopadu 15/2172, 708 33 Ostrava-Poruba, Czech Republic.

Blast furnace and converter sludges are fine-grained waste materials characterized as dangerous waste with a negative impact on the environment. One way of recycling of such materials is briquetting followed by reuse of the material in the blast furnace. In the briquetting process, an important step is the choice of the binder suitable for manufacturing the briquettes with suitable mechanical properties. In this work, the effect of the binder choice (laundry starch UNIPRET, Portland cement) on the reduction of iron oxides in the assessed waste materials during thermal treatment (900, 1000, 1100 °C) is evaluated. Simultaneously, the effect of the binder choice on the amount and composition of the resulting waste gas was evaluated as well as its possible impact on the environment. The performed experiments proved the mutual relationship between the level of iron oxides to metal iron conversion, the binder content and retention temperature. Type of binder also affected the volume of the resulting waste gas. Factor analysis for mixed data (FAMD) proved that the resulting concentrations of the assessed hydrocarbons were correlated (apart from ethyne) and that they are closely associated with the binder applied. Conversely, the concentrations of ethyne, carbon monoxide and carbon dioxide were not associated with the binder but with the retention temperature. FAMD did not show any direct effect of final retention temperature on the amount of the rest of the resulting hydrocarbons. In comparison with the starch-containing briquettes, the cement-containing briquettes were also proved to lead to lower resulting concentrations of PAHs in the waste gas.
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http://dx.doi.org/10.1016/j.wasman.2018.06.051DOI Listing
September 2018

PAH emissions from old and new types of domestic hot water boilers.

Environ Pollut 2017 Jun 26;225:31-39. Epub 2017 Mar 26.

Nanotechnology Centre, VSB-Technical University of Ostrava, 17. listopadu 15/2172, 708 33 Ostrava, Poruba, Czech Republic; Centre Energy Units for Utilization of Non Traditional Energy Sources, VSB-Technical University of Ostrava, 17. listopadu 15/2172, 708 33 Ostrava, Poruba, Czech Republic.

Five different domestic heating boilers (automatic, over-fire, with down-draft combustion and gasification) and three types of fuel (lignite, wood and mixed fuel) were examined in 25 combustion tests and correlated with the emissions of particulate matter (PM), carbon monoxide (CO), total organic carbon (TOC) and 12 polycyclic aromatic hydrocarbons (PAHs with MW = 178-278 g/mol) focusing on particle phase. However, the distribution of 12 PAHs in gas phase was considered as well due to the presence mainly of lighter PAHs in gas phase. The PAHs, as well as the CO and TOC, are the indicators of incomplete combustion, and in this study PAH emission increased significantly with increasing emissions of CO and TOC. The PAHs were mainly detected on PM, their contents were increasing linearly with increasing PM emissions. The highest emission factors of PAHs were measured for boilers of old construction, such as over-fire boiler (5.8-929 mg/kg) and boiler with down-draft combustion (3.1-54.1 mg/kg). Modern types of boilers produced much lower emissions of PAHs, in particular, automatic boiler (0.3-3.3 mg/kg) and gasification boilers (0.2-6.7 mg/kg). In general, the inefficient combustion at reduced output of boilers generated 1.4-17.7 times more emissions of PAHs than the combustion at nominal output of boilers. It is recommended to operate boilers at nominal output with sufficient air supply and to use the proper fuel to minimise PAHs emissions from domestic heating appliances.
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http://dx.doi.org/10.1016/j.envpol.2017.03.034DOI Listing
June 2017

Preparation of Hydrochlorothiazide Nanoparticles for Solubility Enhancement.

Molecules 2016 Aug 2;21(8). Epub 2016 Aug 2.

Department of Pharmaceutical Chemistry, Faculty of Pharmacy, Comenius University, Odbojarov 10, 832 32 Bratislava, Slovakia.

Nanoparticles can be considered as a useful tool for improving properties of poorly soluble active ingredients. Hydrochlorothiazide (Class IV of the Biopharmaceutical Classification System) was chosen as a model compound. Antisolvent precipitation-solvent evaporation and emulsion solvent evaporation methods were used for preparation of 18 samples containing hydrochlorothiazide nanoparticles. Water solutions of surfactants sodium dodecyl sulfate, Tween 80 and carboxymethyl dextran were used in mass concentrations of 1%, 3% and 5%. Acetone and dichloromethane were used as solvents of the model compound. The particle size of the prepared samples was measured by dynamic light scattering. The selected sample of hydrochlorothiazide nanoparticles stabilized with carboxymethyl dextran sodium salt with particle size 2.6 nm was characterized additionally by Fourier transform mid-infrared spectroscopy and scanning electron microscopy. It was found that the solubility of this sample was 6.5-fold higher than that of bulk hydrochlorothiazide.
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http://dx.doi.org/10.3390/molecules21081005DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6274297PMC
August 2016

Toxicity and mutagenicity of low-metallic automotive brake pad materials.

Ecotoxicol Environ Saf 2016 Sep 13;131:37-44. Epub 2016 May 13.

VŠB - Technical University of Ostrava, Nanotechnology Centre, 17. listopadu 15, 708 33 Ostrava, Czech Republic; Southern Illinois University Carbondale, Department of Mechanical Engineering and Energy Processes, Carbondale, IL 62901-4343, USA.

Organic friction materials are standardly used in brakes of small planes, railroad vehicles, trucks and passenger cars. The growing transportation sector requires a better understanding of the negative impact related to the release of potentially hazardous materials into the environment. This includes brakes which can release enormous quantities of wear particulates. This paper addresses in vitro detection of toxic and mutagenic potency of one model and two commercially available low-metallic automotive brake pads used in passenger cars sold in the EU market. The model pad made in the laboratory was also subjected to a standardized brake dynamometer test and the generated non-airborne wear particles were also investigated. Qualitative "organic composition" was determined by GC/MS screening of dichloromethane extracts. Acute toxicity and mutagenicity of four investigated sample types were assessed in vitro by bioluminescence assay using marine bacteria Vibrio fischeri and by two bacterial bioassays i) Ames test on Salmonella typhimurium His(-) and ii) SOS Chromotest using Escherichia coli PQ37 strain. Screening of organic composition revealed a high variety of organic compounds present in the initial brake pads and also in the generated non-airborne wear debris. Several detected compounds are classified by IARC as possibly carcinogenic to humans, e. g. benzene derivatives. Acute toxicity bioassay revealed a response of bacterial cells after exposure to all samples used. Phenolic resin and wear debris were found to be acutely toxic; however in term of mutagenicity the response was negative. All non-friction exposed brake pad samples (a model pad and two commercial pad samples) were mutagenic with metabolic activation in vitro.
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http://dx.doi.org/10.1016/j.ecoenv.2016.05.003DOI Listing
September 2016

Recycling of blast furnace sludge by briquetting with starch binder: Waste gas from thermal treatment utilizable as a fuel.

Waste Manag 2016 Feb 9;48:471-477. Epub 2015 Dec 9.

VŠB-Technical University of Ostrava, Nanotechnology Centre, 17. listopadu 15/2172, 708 33 Ostrava-Poruba, Czech Republic.

Steel plants generate significant amounts of wastes such as sludge, slag, and dust. Blast furnace sludge is a fine-grained waste characterized as hazardous and affecting the environment negatively. Briquetting is one of the possible ways of recycling of this waste while the formed briquettes serve as a feed material to the blast furnace. Several binders, both organic and inorganic, had been assessed, however, only the solid product had been analysed. The aim of this study was to assess the possibilities of briquetting using commonly available laundry starch as a binder while evaluating the possible utilization of the waste gas originating from the thermal treatment of the briquettes. Briquettes (100g) were formed with the admixture of starch (UNIPRET) and their mechanical properties were analysed. Consequently, they were subjected to thermal treatment of 900, 1000 and 1100°C with retention period of 40min during which was the waste gas collected and its content analysed using gas chromatography. Dependency of the concentration of the compounds forming the waste gas on the temperature used was determined using Principal component analysis (PCA) and correlation matrix. Starch was found to be a very good binder and reduction agent, it was confirmed that metallic iron was formed during the thermal treatment. Approximately 20l of waste gas was obtained from the treatment of one briquette; main compounds were methane and hydrogen rendering the waste gas utilizable as a fuel while the greatest yield was during the lowest temperatures. Preparation of blast furnace sludge briquettes using starch as a binder and their thermal treatment represents a suitable method for recycling of this type of metallurgical waste. Moreover, the composition of the resulting gas is favourable for its use as a fuel.
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http://dx.doi.org/10.1016/j.wasman.2015.11.047DOI Listing
February 2016

Preparation of risedronate nanoparticles by solvent evaporation technique.

Molecules 2014 Nov 4;19(11):17848-61. Epub 2014 Nov 4.

Department of Chemical Drugs, Faculty of Pharmacy, University of Veterinary and Pharmaceutical Sciences, Palackeho 1/3, Brno 61242, Czech Republic.

One approach for the enhancement of oral drug bioavailability is the technique of nanoparticle preparation. Risedronate sodium (Biopharmaceutical Classification System Class III) was chosen as a model compound with high water solubility and low intestinal permeability. Eighteen samples of risedronate sodium were prepared by the solvent evaporation technique with sodium dodecyl sulfate, polysorbate, macrogol, sodium carboxymethyl cellulose and sodium carboxymethyl dextran as nanoparticle stabilizers applied in three concentrations. The prepared samples were characterized by dynamic light scattering and scanning electron microscopy. Fourier transform mid-infrared spectroscopy was used for verification of the composition of the samples. The particle size of sixteen samples was less than 200 nm. Polysorbate, sodium carboxymethyl dextran and macrogol were determined as the most favourable excipients; the particle size of the samples of risedronate with these excipients ranged from 2.8 to 10.5 nm.
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http://dx.doi.org/10.3390/molecules191117848DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6271162PMC
November 2014

Modified clay minerals efficiency against chemical and biological warfare agents for civil human protection.

J Hazard Mater 2014 Apr 12;271:65-72. Epub 2014 Feb 12.

Nanotechnology Centre, VŠB-Technical University of Ostrava, 17. listopadu 15, Poruba, Ostrava 708 33, Czech Republic. Electronic address:

Sorption efficiencies of modified montmorillonite and vermiculite of their mono ionic Na and organic HDTMA and HDP forms were studied against chemical and biological warfare agents such as yperite and selected bacterial strains. Yperite interactions with modified clay minerals were observed through its capture in low-density polyethylene foil-modified clay composites by measuring yperite gas permeation with using chemical indication and gas chromatography methods. The antibacterial activities of synthetized organoclays were tested against selected Gram-positive and Gram-negative bacterial species in minimum inhibitory concentration tests. The obtained results showed a positive influence of modified clay minerals on the significant yperite breakthrough-time increase. The most effective material was the polyethylene-Na form montmorillonite, while the polyethylene-Na form vermiculite showed the lowest efficiency. With increasing organic cations loading in the interlayer space the montmorillonite efficiency decreased, and in the case of vermiculite an opposite effect was observed. Generally the modified montmorillonites were more effective than modified vermiculites. The HDP cations seem to be more effective compare to the HDTMA. The antibacterial activity tests confirmed efficiency of all organically modified clay minerals against Gram-positive bacteria. The confirmation of antibacterial activity against Y. pestis, plague bacteria, is the most interesting result of this part of the study.
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http://dx.doi.org/10.1016/j.jhazmat.2014.01.059DOI Listing
April 2014

Volatile fatty acid evolution in biomass mixture composts prepared in open and closed bioreactors.

Waste Manag 2013 May 16;33(5):1104-12. Epub 2013 Feb 16.

Nanotechnology Centre, VŠB-Technical University of Ostrava, 17. listopadu 15, 708 33 Ostrava-Poruba, Czech Republic.

In this study we observed the production of volatile fatty acids (VFAs) during the composting process of compost heaps in two different bioreactors (open and closed) at three different depths (0, 40 and 80 cm). The compost was prepared as a mixture of bio-waste, horse manure, grass and sawdust to ensure sufficient pH conditions in compost heaps. VFA contents in the composting materials were analysed weekly over 14-119 d. The degradation process was monitored, along with temperature, pH, total organic carbon, oxidizable carbon and mono- and oligosaccharides. VFA contents were evaluated with regard to the depth of the sample site in the compost heap and to conditions in the bioreactors. The maximum VFA occurrence was observed during the first 35 d; acetic and propionic acids in particular were determined to occur in each sample. Considerable variations in their formation and elimination were observed in the two bioreactors as well as at the various depths in the compost heaps. Significant correlations were found between individual VFAs, as well as between VFA concentrations and organic carbon contents.
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http://dx.doi.org/10.1016/j.wasman.2013.01.021DOI Listing
May 2013

Synthesis of carbon nanotubes with and without catalyst particles.

Nanoscale Res Lett 2011 Apr 7;6(1):303. Epub 2011 Apr 7.

IFW Dresden, P,O, Box 270116, 01069 Dresden, Germany.

The initial development of carbon nanotube synthesis revolved heavily around the use of 3d valence transition metals such as Fe, Ni, and Co. More recently, noble metals (e.g. Au) and poor metals (e.g. In, Pb) have been shown to also yield carbon nanotubes. In addition, various ceramics and semiconductors can serve as catalytic particles suitable for tube formation and in some cases hybrid metal/metal oxide systems are possible. All-carbon systems for carbon nanotube growth without any catalytic particles have also been demonstrated. These different growth systems are briefly examined in this article and serve to highlight the breadth of avenues available for carbon nanotube synthesis.
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http://dx.doi.org/10.1186/1556-276X-6-303DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3211370PMC
April 2011

The polycyclic aromatic hydrocarbon concentrations in soils in the Region of Valasske Mezirici, the Czech Republic.

Geochem Trans 2009 Dec 14;10:12. Epub 2009 Dec 14.

Centre of Nanotechnology, VSB - Technical University of Ostrava, 17.listopadu 15, 708 33 Ostrava - Poruba, Czech Republic.

The polycyclic aromatic hydrocarbon (PAH) contamination of urban, agricultural and forest soil samples was investigated from samples obtained in the surroundings of Valasske Mezirici. Valasske Mezirici is a town located in the north-east mountainous part of the Czech Republic, where a coal tar refinery is situated. 16 PAHs listed in the US EPA were investigated. Organic oxidizable carbon was also observed in the forest soils. The PAH concentrations ranged from 0.86-10.84 (with one anomalous value of 35.14) and 7.66-79.39 mg/kg dm in the urban/agricultural and forest soils, respectively. While the PAH levels in the urban/agricultural soils are within the range typically found in industrialized areas, the forest soils showed elevated PAH concentrations compared to other forest soils in Western and Northern Europe. The PAH concentrations and their molecular distribution ratios were studied as functions of the sample location and the meteorological history. The soils from localities at higher altitudes above sea level have the highest PAH concentrations, and the PAH concentrations decrease with increasing distance from the town.
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http://dx.doi.org/10.1186/1467-4866-10-12DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2804567PMC
December 2009

Preparation of organovermiculites using HDTMA: structure and sorptive properties using naphthalene.

J Colloid Interface Sci 2008 Nov 22;327(2):341-7. Epub 2008 Aug 22.

Nanotechnology Centre, VSB-Technical University of Ostrava, 17. Listopadu 15, 708 33 Ostrava-Poruba, Czech Republic.

Three types of organovermiculites with various organic cation (HDTMA) loading were prepared to be used as sorptive material for non-ionic organic compounds. The prepared materials were characterized using XRD and TOC analysis. The experiments evolved the fact that lower loading of HDTMA is more acceptable for sorption of neutral organic molecules from aqueous solutions. One of the possible models of intercalated molecules arrangement in vermiculite spacing was proposed.
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http://dx.doi.org/10.1016/j.jcis.2008.08.026DOI Listing
November 2008