Wyniki wyszukiwania - BazTech

1

Wpływ poli(ε-kaprolaktonu) na ekspresję i aktywność fosfatazy alkalicznej w ludzkich komórkach osteogennych

Leszczyńska J., Wójtowicz J., Olkowski R., Komasa J., Ulański P., Lewandowska-Szumieł M.

Engineering of Biomaterials

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2011

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Vol. 14, no. 103

13--16

PL

Poli(ε-kaprolakton) jest materiałem wykorzystywanym jako rusztowanie dla komórek w inżynierii tkankowej kości. Na podstawie danych z literatury oraz naszych własnych badań nad reakcją komórek osteogennych na bezpośredni kontakt z poli(ε-kaprolaktonem) można przypuszczać, iż materiał ten może wpływać na poziom markerów różnicowania komórek w kierunku osteoblastów. Celem niniejszej pracy było zbadanie wpływu poli(ε-kaprolaktonu) na ekspresję oraz aktywność wczesnego markera procesu różnicowania komórek osteogennych, jakim jest fosfataza zasadowa. Przy użyciu reakcji łańcuchowej polimerazy DNA z analizą ilości produktu w czasie rzeczywistym (real-time PCR) analizowano ekspresję genu fosfatazy zasadowej natomiast aktywność enzymu oznaczono kolorymetrycznym testem firmy Sigma. Otrzymane wyniki wskazują, iż kontakt ludzkich osteoblastów z powierzchnią poli(ε-kaprolaktonu) powoduje podwyższoną ekspresję genu fosfatazy zasadowej oraz podwyższoną aktywność tego enzymu. Fosfataza zasadowa nie jest specyficznym markerem osteoblastów, jednakże jej podwyższony poziom towarzyszy wczesnym etapom różnicowania w kierunku fenotypu komórek osteogennych. Uzyskane wyniki uzasadniają podjęcie dalszych badań nad możliwym wpływem poli(ε-kaprolaktonu) na różnicowanie osteoblastów.

EN

Poly(ε-caprolactone) is a material used as a scaffold for cells in bone tissue engineering. On the basis of data from literature as well as own research it was concluded that this material can influence the levels of markers of cell differentiation towards osteoblasts. The aim of this paper was to investigate the effect of poly(ε-caprolactone) on the expression and the activity of the early marker of the cell osteogenic differentiation process – alkaline phosphatase (ALP). Using the quantitative real time polymerase chain reaction (real-time PCR) gene expression of the alkaline phosphatase was analyzed; however, the activity of the enzyme was determined with colorimetric assay from the Sigma company. The obtained results indicated that the contact of human osteoblasts with the surface of poly(ε-caprolactone) causes an increased gene expression of alkaline phosphatase and an increased activity of this enzyme. Although a high level of ALP does not prove the PCL influence on the osteogenic differentiation of cells into mature osteoblasts, because this enzyme is a non-specific marker of the differentiation process. The obtained results justify undertaking further studies on the possible impact of poly(ε-caprolactone) on osteoblast differentiation.

2

Variational calculations on H2+ 4 using exponentially correlated Gaussian wave functions

Bachorz R., Komasa J.

Computational Methods in Science and Technology

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2005

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Vol. 11, nr 1

5-9

EN

The method of exponentially correlated Gaussian (ECG) wave functions is extended to the case of multicenter molecular systems with nuclei arranged in a 3-dimensional space. A particular case of a four-center two-electron system, H 2+ 4, is studied by means of the variational approach. The energies reported in this work are the most accurate available to date.

3

Ekponentially correlated gaussian functions in yariational calculations. the EF 1sigma+g state of hydrogen molecule

Komasa J., Cencek W.

Computational Methods in Science and Technology

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2003

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Vol. 9, nr 1-2

79-92

EN

The Born-Oppenheimer (BO) potential energy curve, the adiabatic and the relativistic corrections for the EF state of the hydrogen molecule are calculated for the internuclear distances ranging from 0.01 to 20 bohr. 600-term variational expansions of exponentially correlated Gaussian (ECG) functions are used. The BO energies and the adiabatic corrections are more accurate than previously reported and the relativistic calculations confirm existing literature values.

4

Efficiency of matrix elements computations on parallel systems

Torchała M., Komasa J.

Computational Methods in Science and Technology

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2003

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Vol. 9, nr 1-2

137-145

EN

Experience with adapting sequential programs to a parallel environment is shared with the reader. Our programs are used in quantum-chemical calculations but certain parts of them are of general application and our results can be adapted to other types of problems. Several PC nodes are connected through a fast network and Consolidated to a cluster. Our applications make use of the Message Passing Interface environment. Encouraging results concerning speedup and efficiency have been obtained. Experiments leading to a superlinear speedup using the hyperthreading technology are also reported.

5

The ground state of (He-H-He)(+) from correlated ab initio calculations

Komasa J., Rychlewski J.

Polish Journal of Chemistry

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1998

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Vol. 72, nr 7S

1353-1360

EN

He2H(+) ion in its ground state is studied by means of ab initio methods taking into account the electron correlation. Geometry optimization at the CCSD(T)/cc-pV5Z level of theory has been performed and the potential energy hypersurface scan is presented. The optimum conformation is linear and symmetric with the proton at the He-He midpoint and the He-H distance equal to 1.75 bohr. Stabilization energy with respect to the He2H(+) --- HeH(+) + He dissociation channel has been computed. Additionally, a single point variational calculations with the use of the Exponentially Correlated Gaussian wave functions have been performed. They supply an upper bound to both the total electronic energy (-5.903505 hartree) and the stabilization energy (-13.224 kcal/mol). A comparison of the results from both the perturbational coupled cluster and variational methods is presented.