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Temperature effect on properties of β-galactosidase entrapped in alginate matrix: an experimental research supported by molecular modeling

Labus K., Radosiński Ł., Kuchta B., Trusek-Hołownia A.

Inżynieria i Aparatura Chemiczna

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2015

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Nr 3

98--100

PL

Badania składały się z dwu części: eksperymentalnego wyznaczenia wpływu temperatury na właściwości immobilizowanej β-galaktozydazy oraz wstępnego modelowania dynamiki zmian w strukturze matrycy alginian-Ca2+ w zależności od temperatury na poziomie molekularnym. Na podstawie uzyskanych wyników można stwierdzić, że takie połączenie badań eksperymentalnych z symulacjami komputerowymi na poziomie cząsteczkowym pozwala na uzyskanie bardziej szczegółowej wiedzy na temat dynamiki układu, co w konsekwencji stwarza możliwość lepszej kontroli i optymalizacji procesu prowadzonego z wykorzystaniem immobilizowanego enzymu.

EN

The current study was separated into two parts: experimental study of temperature impact on activity and stability of immobilized β-galactosidase and preliminary modeling of changes generated in alginate-Ca2+ matrix with respect to temperature using molecular dynamics approach. On the basis of obtained results it can be stated that combination of experimental research and computer simulations on molecular level provides an additional insight greatly enhancing capabilities to control and optimize the process using immobilized biocatalyst.

2

Melting transitions of monolayers adsorbed in cylindrical nanopores

Firlej L., Kuchta B.

Materials Science Poland

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2006

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Vol. 24, No. 2/2

443--451

EN

Melting of krypton layers adsorbed in models of MCM-41 porous silica and of carbon nanotubes has been simulated using Monte Carlo methods. We have shown that the melting mechanism depends on the strength of the atom-wall interaction and on the number of layers adsorbed in the pore. Every new layer stabilizes the layers already present in the system. In the carbon nanotubes we found that adsorption of the second layer leads to a freezing of the first one at constant temperature.

3

Mechanism of adsorption in cylindrical nanopores. The roles of adsorbate-adsorbate interactions in stabilizing the adsorbed phase

Kuchta B., Firlej L.

Materials Science Poland

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2006

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Vol. 24, No. 2/2

432--442

EN

Mechanism of adsorption in nanometric cylindrical pores has been analysed. Grand canonical Monte Carlo simulations were performed for two model systems: krypton and argon, adsorbed in an ideal (smooth) cylindrical silica pore of diameter 2R = 4 nm. The role of interatomic (adsorbate-adsorbate) interactions and atom-wall (adsorbate-adsorbent) forces in the mechanism of adsorption has been discussed. It has been shown that the correlation between these two energy components plays a crucial role in layering and capillary condensation transitions. The stability of different stages of adsorption has been analysed and discussed taking into consideration fluctuations of energy and number of adsorbed atoms during simulations.

4

Computer Simulations of Systems in Confined Geometries

Kuchta B., Firlej R.

Polish Journal of Chemistry

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2002

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Vol. 76 / nr 2-3

219-234

EN

Basic simulation methods in porous material are reviewed. The presentation is focused on different simulation techniques and interaction models, describing the forces between molecules of the fluid and the adsorbent walls. The basic simulation techniques, grandcanonical Monte Carlo, Gibbs ensemble Monte Carlo and buffering field Molecular Dynamics, are presented. The methods to calculate adsorbate-adsorbate and adsorbateadsorbent interaction parameters have been discussed. Examples of the simulations of adsorption in carbon nanotubes and silicates are presented.

5

Phase transformations in locally anharmonic systems. Susceptibility approach to orientational instabilities in molecular solids

Kuchta B., Luty T.

Polish Journal of Chemistry

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1998

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Vol. 72, nr 2

426-432

EN

A model of the structural transformation has been discussed, where the local potential is anharmonic but single-welled. Such potential representants a Hamiltonian to model the structural phase transition in charge-transfer molecular crystals A-TCNB (anthracene-tetracyanobenzene). The conditions for the instability and transformation have been found, using the static susceptibility approach, and compared with the variational approximation. The latter method gives a six times lower transition temperature. The fluctuations and entropy are pointed out as the cause of this difference. The exact transition temperature has been calculated by simple Monte Carlo simulations. A comparison with a double-welled case, which models the structural transition in N-TCNB molecular crystal (naphthalene-tetracyanobenzene), has been presented.