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wizyta

od 2020-09-20

Dr Sławomir Kuśmia  | 1995-10 <> 2004-09

Doktorant

  57219521820   

Publikacje                Magistrowie           Seminaria


8.

Dobies M., Kempka M., Kuśmia S., Jurga S.

Acid induced gelation of low methoxyl pectins studied by 1H NMR and rheological methods The various 1H NMR techniques (1H NMRD, water proton spin-spin relaxation time and diffusion measurements) in combination with rheological measurements were applied to the analysis of the acid induced gelation of 3% w/w aqueous LM pectin solutions at 279 K. A decrease of the pH value of solutions from 5 to 2.6 leads to a slowdown in the dynamics of the water molecules and to a substantial modification in the structure of the system studied. The most significant changes in the 1H NMRD and T2 measurements were observed when the pH was varied from 5 to 3, which reflected an increase in the stiffness of the pectin chains caused by non-ionic associations and by an increase of water molecules that were trapped between the pectin chains in the gelled ste. The results obtained by the rheological method are consistent with those of 1H NMR, indicating a solution-like mechanical response for the sample at pH 5 and a gel-like response at pH 3. Results of 1H NMR measurements have also shown an important role for aggregation processes of the LM pectin molecules in the acid-induced gel network formation.

Applied Magnetic Resonance, 34(1-2), 71-81 (2008)

DOI: 10.1007/s00723-008-0107-7   (Pobrane:  2020-10-21)


7.

Zalewski T., Lubiatowski P., Jaroszewski J., Szcześniak E., Kuśmia S., Kruczyński J., Jurga S.

Scaffold-aided repair of articular cartilage studied by MRI Objective The objective of the study was to evaluate the ability of the noninvasive magnetic resonance techniques to monitor the scaffold-aided process of articular cartilage repair.
Materials and methods Defects of 4 mm in diameter and 3 mm in depth were created in right knees of 30 adolescent white New Zealand rabbits. Fourteen rabbits were implanted with poly(lactide-co-glycolic acid) (PLGA) scaffold trimmed to match the size and the shape of the defect (PLGA+ group). No procedure was applied to the remaining 16 animals (PLGA- group). Animals were sacrificed sequentially at 4, 12, and 24 weeks after the surgery and magnetic resonance T(2)-weighted images (400 MHz) of the dissected bone plugs at eight different echo times were taken to derive T(2) relaxation time. The images and the T(2) time dependencies versus the tissue depth were statistically analyzed. Histological results of bone plugs were evaluated using semiquantitative histological scales.
Results The results obtained for PLGA repair tissue were evaluated versus the PLGA- group and the healthy tissue harvested from the opposite knee (reference group), and compared with histological results (hematoxylin and eosin staining). The magnetic resonance images and T(2) relaxation time profiles taken 4 weeks after surgery for both the PLGA- and PLGA+ group did not reveal the tissue reconstruction. After 12 weeks of treatment T(2) time dependence indicates a slight reconstruction for PLGA+ group. The T(2) time dependence obtained for PLGA+ samples taken after 24 weeks of treatment resembled the one observed for the healthy cartilage, indicating tissue reconstruction in the form of fibrous cartilage. The tissue reconstruction was not observed for PLGA-samples.
Conclusion The study revealed correlation between magnetic resonance and histology data, indicating the potential value of using MRI and spatial variation of T (2) as the noninvasive tools to evaluate the process of articular cartilage repair. It also suggested, that the PLGA scaffold-aided treatment could help to restore the proper architecture of collagen fibrils.

Magnetic Resonance Materials in Physics, Biology and Medicine, 21(3), 177-185 (2008)

DOI: 10.1007/s10334-008-0108-4   (Pobrane:  2020-10-21)


6.

Dobies M., Kuśmia S., Jurga S.

1H NMR and rheological studies of the calcium induced gelation process in aqueous low methoxyl pectin solutions The H-1 NMR relaxometry in combination with water proton spin-spin relaxation time measurements and rheometry have been applied to study the ionic gelation of 1% w/w aqueous low methoxyl pectin solution induced by divalent Ca2+ cations from a calcium chloride solution. The model-free approach to the analysis of H-1 NMR relaxometry data has been used to separate the information on the static (β) and dynamic (<τ(c)>) behaviour of the systems tested. The H-1 NMR results confirm that the average mobility of both water and the pectin molecules is largely dependent on the concentration of the cross-linking agent. The character of this dependency (β, <τ(c)> and T-2 vs. CaCl2 concentration) is consistent with the two-stage gelation process of low methoxyl pectin, in which the formation of strongly linked dimer associations (in the range of 0-2.5 mM CaCl2) is followed by the appearance of weak inter-dimer aggregations (for CaCl2 >= 3.5 mM). The presence of the weak gel structure for the sample with 3.5 mM CaCl2 has been confirmed by rheological measurements. Apart from that, the T1 and T2 relaxation times have been found to be highly sensitive to the syneresis phenomenon, which can be useful to monitor the low methoxyl pectin gel network stability.

Acta Physica Polonica A, 108(1), 33 (2005)

DOI: 10.12693/APhysPolA.108.33
WWW: http://przyrbwn.icm.edu.pl/APP/PDF/108/a108z104.pdf   (Pobrane:  2021-01-10)


5.

Jurga J., Kulczyk T., Kuśmia S., Limanowska-Shaw H.

Dental Forum, 30(1), 177-185 (2004)


4.

Kuśmia S., Kozak M., Szcześniak E., Domka L., Jurga S.

Studies of water penetration into LDPE-calcium lactate composite Penetration of water into low-density polyethylene-calcium lactate composite is studied with NMR techniques. The presence of filler speeds up the water uptake by the polymer matrix and facilitates polyethylene degradation. Spatial distribution of absorbed water molecules within the composite visualised with MRI corroborates differences in dynamical behaviour of the absorbed water molecules revealed by T-2 measurements.
(C) 2003 Elsevier Inc. All rights reserved.

Solid State Nuclear Magnetic Resonance, 25(1-3), 173-176 (2004)

DOI: 10.1016/j.ssnmr.2003.03.027   (Pobrane:  2020-10-21)


3.

Foltynowicz Z., Jakubiak P., Judek Ł., Kozak M., Kuśmia S., Fojud Z., Domka L., Jurga S.

Polietylen modyfikowany mleczanem wapnia W pracy przedstawiono metodę otrzymywania polietylenu modyfikowanego mleczanem wapnia oraz pochodną krzemoorganiczną mleczanu wapnia. Stosowano różne ilości napełniacza. Uzyskane tworzywa biorozpraszalne poddano badaniom mechanicznym.

Mat. V Konferencji Naukowo-Technicznej "Polimery i Kompozyty Konstrukcyjne", , 61-65 (2002)


2.

Kuśmia S., Szcześniak E., Jurga S.

Magnetic resonance imaging of solid polymer composite In this paper the use of magic echo phase encoding (MEPSI) technique to obtain magnetic resonance image of the solid polymer composite is reported. The 2D version of MEPSI without slice selection has been adapted. The experiment shows that one can obtain an image of a solid sample whose transverse relaxation time is of the order of dozen of microseconds.

Molecular Physics Reports, 33, 184-187 (2001)

WWW: http://www.ifmpan.poznan.pl/mol/
ISSN: 1505-1250   (Pobrane:  2021-01-07)


1.

Kuśmia S., Szcześniak E., Jurga S.

Visualisation of fluid migration into porous poly(vinylalkohol) using MRI techniques Information on migration of liquids into porous media and on mobility of the absorbed fluids is of great relevance for the theory and for many branches of the materials science. In this paper we use magnetic resonance microimaging to visualise migration of water and chloroform into porous poly(vinylalkohol) (PVA). The images taken using gradient echo fast imaging (GEFI) and constant time imaging (CTI) methods show differences, which are assumed to reflect the restriction of mobility of water molecules due to formation of hydrogen bonds with hydrophilic PVA.

Molecular Physics Reports, 28, 106-108 (2000)

WWW: http://www.ifmpan.poznan.pl/mol/
ISSN: 1505-1250   (Pobrane:  2021-01-07)


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