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11.
Rastislav Serbin Yaroslav R. Bazel Marcel Torok Josef Havel Ioseph S. Balogh Zholt O. Kormosh Gabriela Holéczyová Vasil Andruch 《中国化学会会志》2009,56(6):1168-1174
A new, simple, rapid, sensitive, efficient and low‐cost spectrophotometric procedure for the determination of gold was developed. The method is based on the reaction of [AuCl4]? with 2‐[2‐(4‐dimethylaminophenyl)‐vinyl]‐1,3,3‐trimethyl‐3H‐indolium reagent to form a colored ion associate extractable by various organic solvents. The molar absorptivity of the ion associates is in the range (5.7–9.2) × 104 L mol?1 cm?1 depending on the extractant. Butyl acetate was chosen as the extractant. The optimum reaction conditions were established: pH 2–4, concentration of the dye reagent (0.8–1.5) × 10?4 mol L?1. The determination of gold is not hindered even by a 1000‐fold concentration of Ni and Co; a 500‐fold concentration of Pb and Zn; a 100‐fold concentration of Bi, Cu, Cd, Pt, Rh and Ru; or a 20‐fold concentration of Ag. The established method was applied to the determination of gold in model samples and enriched polymetallic ores. 相似文献
12.
Whole genome amplification induced bias in the detection of KRAS‐mutated cell populations during colorectal carcinoma tissue testing
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Jana Stranska Sylwia Jancik Rastislav Slavkovsky Veronika Holinkova Miroslava Rabcanova Petr Vojta Marian Hajduch Jiri Drabek 《Electrophoresis》2015,36(6):937-940
Whole genome amplification replicates the entire DNA content of a sample and can thus help to circumvent material limitations when insufficient DNA is available for planned genetic analyses. However, there are conflicting data in the literature whether whole genome amplification introduces bias or reflects precisely the spectrum of starting DNA. We analyzed the origins of discrepancies in KRAS (Kirsten rat sarcoma viral oncogene homolog gene) mutation detection in six of ten samples amplified using the GenomePlex® Tissue Whole Genome Amplification kit 5 (WGA5; Sigma‐Aldrich, St. Louis, MO, USA) and KRAS StripAssay® (KRAS SA; ViennaLab Diagnostics, Vienna, Austria). We undertook reextraction, reamplification, retyping, authentication, reanalysis, and reinterpretation to determine whether the discrepancies originated during the preanalytical, analytical, and/or interpretative phase of genotyping. We conclude that a combination of glass slide/sample heterogeneity and biased amplification due to stochastic effects in the early phases of whole genome amplification (WGA) may have adversely affected the results obtained. Our findings are relevant for both forensic genetics testing and massively parallel sequencing using preamplification. 相似文献
13.
Veronika Šlachtová Simona Bellová Agustina La-Venia Juraj Galeta Martin Dračínský Karel Chalupský Alexandra Dvořáková Helena Mertlíková-Kaiserová Peter Rukovanský Rastislav Dzijak Milan Vrabel 《Angewandte Chemie (International ed. in English)》2023,62(36):e202306828
The development of reagents that can selectively react in complex biological media is an important challenge. Here we show that N1-alkylation of 1,2,4-triazines yields the corresponding triazinium salts, which are three orders of magnitude more reactive in reactions with strained alkynes than the parent 1,2,4-triazines. This powerful bioorthogonal ligation enables efficient modification of peptides and proteins. The positively charged N1-alkyl triazinium salts exhibit favorable cell permeability, which makes them superior for intracellular fluorescent labeling applications when compared to analogous 1,2,4,5-tetrazines. Due to their high reactivity, stability, synthetic accessibility and improved water solubility, the new ionic heterodienes represent a valuable addition to the repertoire of existing modern bioorthogonal reagents. 相似文献
14.
Nina Kolesárová Miroslav Hutňan Viera Špalková Rastislav Kuffa Igor Bodík 《Chemical Papers》2011,65(4):447-453
In this work, long-term operation of a pilot scale mixed anaerobic reactor processing crude glycerol and rapeseed meal is
discussed. These materials are generated as by-products of biodiesel production. Mixed reactor was operated under mesophilic
conditions for the period of 654 days. Total cumulative production of biogas reached 379 m3 (at atmospheric pressure and ambient temperature). Maximum volumetric loading achieved during the operation was 2.17 kg m−3 d−1 for the crude glycerol dose of 2 L. When dosing crude glycerol as a single substrate, average specific production of biogas
of 0.76 m3 per L of the g-phase was achieved. The lack of nutrients in the g-phase had to be compensated by an addition of ammonium
nitrogen in the form of urea into the reactor. Long term processing of crude glycerol demonstrated that accumulation of dissolved
inorganic salts in the reactor can lead to inhibition of the methanogenic activity of microorganisms, causing breakdown of
the system. Co-fermentation of crude glycerol with rapeseed meal provided stable biogas production and it was shown to be
a feasible way of anaerobic degradation of these substrates. At the maximum volumetric load of 1.33 kg m−3 d−1 (500 mL of g-phase and 500 g of rapeseed meal), the average biogas production reached 0.58 m3 d−1. 相似文献
15.
Polycrystalline NiZn ferrites with the chemical formula (Ni0.3Zn0.7)1−xMexFe2O4 where Me is Cu with x=0.05, 0.1 and 0.25 have been prepared by a ceramic method. Certain magnetic properties such as the coercivity Hc, initial permeability μi and saturation magnetisation Ms of the ferrites have been measured and discussed from the point of view of the substituting element contents as well as the total pore volume. The Mössbauer spectra of selected samples have been analysed as well. According to the requirement of particular applications, the properties of NiZn ferrite have to be improved by means of proper substitution of selected ions. 相似文献
16.
Mohammadiparsa Nahid Habibi Safdar Dekan Július Janotová Irena Švec Peter Galdun Ladislav Varga Rastislav Kmječ Tomáš Bujdoš Marek Miglierini Marcel 《Journal of Radioanalytical and Nuclear Chemistry》2019,322(2):691-697
Journal of Radioanalytical and Nuclear Chemistry - The effect of minor substitution of carbon on the structure and magnetic properties of Fe–Si–B–Cu-type metallic glasses was... 相似文献
17.
Monolayers of DNA chains of polymeric dimensions, considered here to be longer than approximately 100 nucleotides, are widely encountered in biomolecular diagnostics as well as present for a model system for investigating behavior of polyelectrolytes at interfaces. A major challenge in advancing such applications is assembling the DNA on the surface in a controlled way. Although covalent immobilization is expected to produce optimal stability, the multitude of potential reactive sites along the contour of long DNA molecules requires that any chemical transformations be strictly site-specific to preserve control over attachment geometry and function. A synthetic approach to fabricating monolayers of DNA genes on gold using polymeric anchor (adhesion) films is presented that (i) possesses stringent site-specificity of surface-attachment, (ii) exhibits excellent stability to elevated temperatures, allowing denaturation of duplex chains at 90 degrees C without loss of surface-linked strands, and (iii) achieves surface coverages suitable for investigating multichain polyelectrolyte behavior in regimes of strong interchain interactions. 相似文献
18.
The oxidative stability of blends of poly(methyl methacrylate) (PMMA) with four types of rubber, poly(ethylene-stat-propylene-stat-5-methylene-2-norbornene) (EPDM), poly(ethylene-stat-vinyl acetate) (EVA), dicarboxy terminated poly(acrylonitrile-stat-butadiene) (NBR) and poly(1,3-butadiene-stat-styrene) (SBR), has been investigated as models for rubber-toughened PMMA. Chemiluminescence was used to monitor the oxidation of the rubber in the blends, revealing an unexpected accelerating effect of PMMA on the oxidation of all the rubbers investigated. The effect varies according to the type of rubber and the temperature. The thermo-oxidative stability of PMMA has also been found to decrease in the presence of the rubber as proved by thermogravimetry, confirming mutually antagonistic effects of PMMA and rubber in the blend oxidation. On the basis of results from all techniques, including identification of oxidation products by FTIR spectroscopy, a possible mechanism is suggested, involving the formation of mobile radicals in PMMA induced by rubber oxidation. These radicals are suggested to play a crucial role in enhancing rubber phase oxidation. 相似文献
19.
Rastislav Monošík Miroslav Streďanský Gabriel Greif Ernest Šturdík 《Central European Journal of Chemistry》2012,10(1):157-164
Amperometric biosensors based on a gold planar electrode and on two types of nanocomposite electrodes consisting of multi-walled
carbon nanotubes for the determination of L-malic acid designed for wine-makers were developed. The biosensors designed for
wine-makers were constructed by immobilization of L-malate dehydrogenase and diaphorase within chitosan layers on the surface
of the electrodes. The coenzyme NAD+ and the electrochemical mediator ferricyanide were present in the measuring solution.
The current resulting from re-oxidation of produced ferrocyanide was measured at a working potential of +300 mV against an
Ag/AgCl reference electrode. The biosensor based on a gold electrode showed linearity over the range 10–520 μM with a detection
limit of 5.41 μM. Calibration curves for biosensors utilizing nanocomposites were obtained both with the linear range of 10
to 610 μM. The detection limits were 1.57 and 1.77 μM, respectively. The biosensors showed satisfactory operational stability
(no loss of sensitivity after 30 consecutive measurements) and storage stability (90% of the initial sensitivity after one
year of storage at room temperature). The results obtained from measurements of wine samples were in a good correlation with
the standard HPLC method. Satisfactory biosensor sensitivity, specificity and stability allowed their successful commercialization. 相似文献
20.
Miroslav Streďanský Rastislav Monošík Vladimír Mastihuba Ernest Šturdík 《Applied biochemistry and biotechnology》2013,171(4):1032-1041
Substrate specificity of 2,7,9-tricarboxypyrroloquinoline quinone (PQQ)-dependent glucose dehydrogenase was investigated in biosensor arrangement for understanding the suitability and the limitations of its use in bioanalysis and bioproduction of chemicals. The study demonstrated a very broad substrate specificity of biosensor utilising soluble form of PQQ-dependent glucose dehydrogenase. Nineteen saccharides out of 31 were oxidised by the sensor. Investigation confirmed strong importance of hydroxyl configuration in the positions 2 and 5 of oxidised saccharides. The broad specificity suggests that the PQQ-dependent glucose dehydrogenase could be utilised for analysis of other sugars than glucose in food samples for various production processes and for biofuel cells. In addition, the results showed that the substrate specificity of enzymes can be effectively and generally studied by biosensor arrangement for research purposes. This layout utilising immobilised enzyme allowed performing comprehensive study using a small amount of enzymes and thus saving the costs and time. 相似文献