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Laccase Immobilisation on Mesostructured Silicas

100%
Bryjak J., Szymańska K., Jarzębski A. B.
Chemical and Process Engineering
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2012
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vol. 33
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issue 4
611-620
EN
Extracellular laccase produced by the wood-rotting fungus Cerrena unicolor was immobilised covalently on the mesostructured siliceous foam (MCF) and three hexagonally ordered mesoporous silicas (SBA-15) with different pore sizes. The enzyme was attached covalently via glutaraldehyde (GLA) or by simple adsorption and additionally crosslinked with GLA. The experiments indicated that laccase bound by covalent attachment remains very active and stable. The best biocatalysts were MCF and SBA-15 with Si-F moieties on their surface. Thermal inactivation of immobilised and native laccase at 80°C showed a biphasic-type activity decay, that could be modelled with 3- parameter isoenzyme model. It appeared that immobilisation did not significantly change the mechanism of activity loss but stabilised a fraction of a stable isoform. Examination of time needed for 90% initial activity loss revealed that immobilisation prolonged that time from 8 min (native enzyme) up to 155 min (SBA-15SF).
2
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Application of FTIR spectroscopy to study the thermal stability of magnesium aspartate-arginine

100%
Hacura A., Marcoin W., Pasterny K.
Polish Journal of Medical Physics And Engineering
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2012
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vol. 18
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issue 1
7-10
EN
FTIR spectroscopy has been applied to study the thermal stability of magnesium aspartatearginine. An attempt has been made, using theoretically predicted IR spectra, to relate the changes in the experimental spectra with the decomposition process of the studied magnesium complex.
3
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Diffractometric examination of the structure of heat-resisting steel-based coatings in different measurement geometries

88%
Kucharska B.
Open Physics
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2011
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vol. 9
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issue 5
1294-1300
EN
Coatings of the composition of 310S heat-resisting steel dopped Al and Ir additions, deposited on a substrate of the same steel by the magnetron sputtering method, were examined. The measurements were made in the classical Bragg-Brentano geometry and by the GXRD method. With the fixed and different position of the coated sample by rotating the sample by angles ψ. The coating as deposited and after being soaked at 400°C for 15 minutes was subjected to examinations. The examination carried out have shown that coatings may have a unique, subtle structure which is metastable and undergoes irreversible changes in the temperatures up to 400°C. It has been found that in the outermost coating zones and zones closer to the substrate, areas occur in the coating structure, which have the different lattice parameter compared to the basic phase. Additionaly, the local period of the structure equal 5.9 nm was found.
4
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Laccase Immobilisation on Mesostructured Silicas

88%
Bryjak J., Szymańska K., Jarzębski A. B.
Chemical and Process Engineering
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2012
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issue 4
5
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Polyurethane Foams with Pyrimidine Rings

75%
Kania E., Lubczak J.
Polish Journal of Chemical Technology
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2014
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vol. 16
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issue 3
1-6
EN
Oligoetherols based on pyrimidine ring were obtained upon reaction of barbituric acid with glycidol and alkylene carbonates. These oligoetherols were then used to obtain polyurethane foams in the reaction of oligoetherols with isocyanates and water. The protocol of foam synthesis was optimized by the choice of proper kind of oligoetherol and synthetic composition. The thermal resistance was studied by dynamic and static methods with concomitant monitoring of compressive strength. The polyurethane foams have similar physical properties as the classic ones except their enhanced thermal resistance. They stand long-time heating even at 200°C. Moreover thermal exposition of foams results generally in increase of their compressive strength.
6
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THE EFFECT OF IONIC CROSSLINKING ON THERMAL PROPERTIES OF HYDROGEL CHITOSAN MEMBRANES

75%
Gierszewska-Drużyńska M., Ostrowska-Czubenko J.
Progress on Chemistry and Application of Chitin and its Derivatives
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2010
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vol. 15
25 - 32
EN
Ionically crosslinked one‑component chitosan (Ch), two‑component chitosan/sodium alginate (Ch/NaAlg) and chitosan/pentasodium tripolyphosphate (Ch/TPP) membranes as well as three‑component chitosan/sodium alginate/pentasodium tripolyphosphate (Ch/NaAlg/TPP) membranes were prepared. Formation of ionic interactions between Ch and NaAlg and/or TPP was confirmed by FTIR analysis. An effect of a crosslinking process on thermal properties of hydrogel membranes was examined using TG/DTG/DTA and DSC methods. Changes in the number of thermal degradation steps of the studied hydrogel membranes were observed. Considering the temperature at which thermal degradation starts as a criterion of the thermal stability, it was concluded that the thermal stability increases according to the series: Ch/NaAlg ≈ Ch/NaAlg/TPP ≈ Ch/TPP
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