Janusz Rosiak - Academia.edu (original) (raw)
Papers by Janusz Rosiak
Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms, 2005
... R. Czechowska-Biskup, B. Rokita, P. Ulanski Corresponding Author Contact Information , E-mail... more ... R. Czechowska-Biskup, B. Rokita, P. Ulanski Corresponding Author Contact Information , E-mail The Corresponding Author and JM Rosiak. Institute of Applied Radiation Chemistry, Technical University of Lodz, Wroblewskiego 15, 93-590 Lodz, Poland. ...
Colloids and Surfaces B: Biointerfaces
This report demonstrates the feasibility of radiation grafting for the preparation of polymer lay... more This report demonstrates the feasibility of radiation grafting for the preparation of polymer layers functionalised with short peptide ligands which promote cell adhesion. Thermoresponsive poly [tri(ethylene glycol) monoethyl ether methacrylate] (PTEGMA) layers were synthesised on a polypropylene substrate by post-irradiation grafting. A cell adhesion moiety, the CF-IKVAVK peptide modified with a methacrylamide function and a fluorescent label were introduced to the surface during the polymerisation process. The amount of CF-IKVAVK was easily controlled by changing its concentration in the reaction mixture. The changes in the surface composition, morphology, philicity and thickness at each step of the polypropylene functionalisation confirmed that the surface modification procedures were successful. The increase in environmental temperature above the cloud point temperature of PTEGMA caused a decrease in surface philicity. The obtained PTEGMA and PTEGMA-peptide surfaces above TCP were tested as scaffolds for fibroblast sheet culture and temperature induced detachment.
International Journal of Biological Macromolecules, 2016
Crosslinked enzyme aggregates comprise more stable and highly concentrated enzymatic preparations... more Crosslinked enzyme aggregates comprise more stable and highly concentrated enzymatic preparations of current biotechnological and biomedical relevance. This work reports the development of crosslinked nanosized papain aggregates using electron beam irradiation as an alternative route for controlled enzyme crosslinking. The nanoparticles were synthesized in phosphate buffer using various ethanol concentrations and electron beam irradiation doses. Particle size increase was monitored using dynamic light scattering. The crosslinking formation by means of bityrosine linkages were measured by fluorescence spectra and the enzymatic activity was monitored using Na-Benzoyl-dl-arginine p-nitroanilide hydrochloride as a substrate. The process led to crosslinked papain nanoparticles with controlled sizes ranging from 6 to 11nm depending upon the dose and ethanol concentration. The irradiation atmosphere played an important role in the final bioactivity of the nanoparticles, whereas argon and nitrous oxide saturated systems were more effective than at atmospheric conditions in terms of preserving papain enzymatic activity. Highlighted advantages of the technique include the lack of monomers and crosslinking agents, quick processing with reduced bioactivity changes, and the possibility to be performed inside the final package simultaneously with sterilization.
Physics in Medicine and Biology, 2005
This work seeks to verify multi-shot clinical applications of stereotactic radiosurgery with a Le... more This work seeks to verify multi-shot clinical applications of stereotactic radiosurgery with a Leksell Gamma Knife model C unit employing a polymer gel-MRI based experimental procedure, which has already been shown to be capable of verifying the precision and accuracy of dose delivery in single-shot gamma knife applications. The treatment plan studied in the present work resembles a clinical treatment case of pituitary adenoma using four 8 mm and one 14 mm collimator helmet shots to deliver a prescription dose of 15 Gy to the 50% isodose line (30 Gy maximum dose). For the experimental dose verification of the treatment plan, the same criteria as those used in the clinical treatment planning evaluation were employed. These included comparison of measured and GammaPlan calculated data, in terms of percentage isodose contours on axial, coronal and sagittal planes, as well as 3D plan evaluation criteria such as dose-volume histograms for the target volume, target coverage and conformity indices. Measured percentage isodose contours compared favourably with calculated ones despite individual point fluctuations at low dose contours (e.g., 20%) mainly due to the effect of T2 measurement uncertainty on dose resolution. Dose-volume histogram data were also found in a good agreement while the experimental results for the percentage target coverage and conformity index were 94% and 1.17 relative to corresponding GammaPlan calculations of 96% and 1.12, respectively. Overall, polymer gel results verified the planned dose distribution within experimental uncertainties and uncertainty related to the digitization process of selected GammaPlan output data.
Physics in Medicine and Biology, 2005
This work describes an experimental procedure with potential to assess the overall accuracy assoc... more This work describes an experimental procedure with potential to assess the overall accuracy associated with gamma knife clinical applications, from patient imaging and dosimetry planning to patient positioning and dose delivery using the automated positioning system of a Leksell Gamma Knife model C. The VIPAR polymer gel-MRI dosimetry method is employed due to its inherent three-dimensional feature and linear dose response over the range of gamma knife applications. Different polymer gel vials were irradiated with single shot gamma knife treatment plans using each of the four available collimator helmets to deliver a maximum dose of 30 Gy. Percentage relative dose results are presented not only in the form of one-dimensional profiles but also planar isocontours and isosurfaces in three dimensions. Experimental results are compared with corresponding Gammaplan treatment planning system calculations as well as acceptance test radiochromic film measurements. A good agreement, within the experimental uncertainty, is observed between measured and expected dose distributions. This experimental uncertainty is of the order of one imaging pixel in the MRI gel readout session (<1 mm) and allows for the verification of single shot gamma knife applications in terms of acceptance specifications for precision in beam alignment and accuracy. Averaging net R(2) results in the dose plateau of the 4 mm and 18 mm collimator irradiated gel vials, which were MR scanned in the same session, provides a crude estimate of the 4 mm output factor which agrees within errors with the default value of 0.870.
Physics in Medicine and Biology, 2005
Despite its advantages, the polymer gel-magnetic resonance imaging (MRI) method has not, as yet, ... more Despite its advantages, the polymer gel-magnetic resonance imaging (MRI) method has not, as yet, been successfully employed in dosimetry of low energy/low dose rate photon-emitting brachytherapy sources such as 125I or 103Pd interstitial seeds. In the present work, two commercially available 125I seed sources, each of approximately 0.5 U, were positioned at two different locations of a polymer gel filled
International Journal of Radiation Applications and Instrumentation. Part C. Radiation Physics and Chemistry
The ability of polymer to crosslink or exposure to radiation is frequently represented by a G val... more The ability of polymer to crosslink or exposure to radiation is frequently represented by a G value, the number of crosslinks per 100 eV absorbed. Several methods are available for its determination, the most frequent being the dose D s required to form an incipient network since (with many systems) this corresponds to one crosslinked unit per weight average molecular (~ = 1). Its determination therefore depends on a knowledge of the molecular weight of the starting polymer. An alternative method, far less frequently used, is to measure the degree of swelling of a crosslinked network. This involves a knowledge of the Flory-Huggins interaction parameter/~ and of the initial number average M,¢0). However if the concentration V, of effective chains (deduced from swelling) is plotted against dose D, the slope gives G (X) directly, independent of M.¢0). This applies only when the system is very largely crosslinked. It may also be used to determine G(X) even when starting from the monomer itself (i.e. combining polymerization and crosslinking). It is shown that, for a series of polymers, irradiated either as liquids or in solution, the theoretical relation between swelling and crosslink density is followed, and the G(X) values derived from swelling compare well with those given in the literature, and based on gel fraction.
International Journal of Radiation Applications and Instrumentation. Part C. Radiation Physics and Chemistry
ABSTRACT
International Journal of Radiation Applications and Instrumentation. Part C. Radiation Physics and Chemistry
International Journal of Radiation Applications and Instrumentation. Part C. Radiation Physics and Chemistry
Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms
Irradiation of dilute, deoxygenated aqueous solutions of hydrophilic polymers with high-dose puls... more Irradiation of dilute, deoxygenated aqueous solutions of hydrophilic polymers with high-dose pulses of fast electrons leads to the simultaneous formation of many radicals on each polymer chain. These radicals undergo mainly intramolecular recombination. In this way internally crosslinked macromolecules ± nanogels ± are formed. Current data on poly(vinyl pyrrolidone) show that during this process the weight-average molecular weight remains almost constant, but there is a pronounced decrease in the radius of gyration of macromolecules, an eect expected for the formation of compact, internally crosslinked structures.
![Research paper thumbnail of Polycomplexes of Bovine Serum Albumin with Poly[2-Methacryloyloxy) Ethyl]Trimethyl Ammonium Chloride](https://attachments.academia-assets.com/71781616/thumbnails/1.jpg)
](Eurasian Chemico-Technological Journal
Complex formation between bovine serum albumin and water-soluble synthetic cationic polyelectroly... more Complex formation between bovine serum albumin and water-soluble synthetic cationic polyelectrolyte poly[2-methacryloyloxy)ethyl]trimethyl ammonium chloride has been studied in aqueous solutions by turbidimetric and viscometric methods. It was found that the structure of polycomplex is compact and its stability strongly depends on the environment. Formation of insoluble polycomplexes is observed in solutions with low ionic strength and pH, higher than 5.0. This pH value corresponds to the isoelectric point of the protein, so at lower pH the biopolymer macromolecules gain the positive charge and not able to be bound by the positively charged macromolecules of poly[2-methacryloyloxy)ethyl]trimethyl ammonium chloride. An increase of pH within 5.0-11.0 leads to further stabilization of polycomplex because of appearance of additional negative charges on biomacromolecules, caused by ionization of acidic groups. It was found that the main forces, which are responsible for the complexation,...
Radiation Physics and Chemistry, 2017
Farmacja Polska, Jun 1, 2008
Radiation Physics and Chemistry, Mar 1, 2002
... Piotr Ula ski Corresponding Author Contact Information , E-mail The Corresponding Author , S ... more ... Piotr Ula ski Corresponding Author Contact Information , E-mail The Corresponding Author , S awomir Kad ubowski and Janusz M. Rosiak. ... (2)), α=0.73 (best fit), initial average number of radicals per chain Z RO =18. View Within Article. ...
Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms, 2005
... R. Czechowska-Biskup, B. Rokita, P. Ulanski Corresponding Author Contact Information , E-mail... more ... R. Czechowska-Biskup, B. Rokita, P. Ulanski Corresponding Author Contact Information , E-mail The Corresponding Author and JM Rosiak. Institute of Applied Radiation Chemistry, Technical University of Lodz, Wroblewskiego 15, 93-590 Lodz, Poland. ...
Colloids and Surfaces B: Biointerfaces
This report demonstrates the feasibility of radiation grafting for the preparation of polymer lay... more This report demonstrates the feasibility of radiation grafting for the preparation of polymer layers functionalised with short peptide ligands which promote cell adhesion. Thermoresponsive poly [tri(ethylene glycol) monoethyl ether methacrylate] (PTEGMA) layers were synthesised on a polypropylene substrate by post-irradiation grafting. A cell adhesion moiety, the CF-IKVAVK peptide modified with a methacrylamide function and a fluorescent label were introduced to the surface during the polymerisation process. The amount of CF-IKVAVK was easily controlled by changing its concentration in the reaction mixture. The changes in the surface composition, morphology, philicity and thickness at each step of the polypropylene functionalisation confirmed that the surface modification procedures were successful. The increase in environmental temperature above the cloud point temperature of PTEGMA caused a decrease in surface philicity. The obtained PTEGMA and PTEGMA-peptide surfaces above TCP were tested as scaffolds for fibroblast sheet culture and temperature induced detachment.
International Journal of Biological Macromolecules, 2016
Crosslinked enzyme aggregates comprise more stable and highly concentrated enzymatic preparations... more Crosslinked enzyme aggregates comprise more stable and highly concentrated enzymatic preparations of current biotechnological and biomedical relevance. This work reports the development of crosslinked nanosized papain aggregates using electron beam irradiation as an alternative route for controlled enzyme crosslinking. The nanoparticles were synthesized in phosphate buffer using various ethanol concentrations and electron beam irradiation doses. Particle size increase was monitored using dynamic light scattering. The crosslinking formation by means of bityrosine linkages were measured by fluorescence spectra and the enzymatic activity was monitored using Na-Benzoyl-dl-arginine p-nitroanilide hydrochloride as a substrate. The process led to crosslinked papain nanoparticles with controlled sizes ranging from 6 to 11nm depending upon the dose and ethanol concentration. The irradiation atmosphere played an important role in the final bioactivity of the nanoparticles, whereas argon and nitrous oxide saturated systems were more effective than at atmospheric conditions in terms of preserving papain enzymatic activity. Highlighted advantages of the technique include the lack of monomers and crosslinking agents, quick processing with reduced bioactivity changes, and the possibility to be performed inside the final package simultaneously with sterilization.
Physics in Medicine and Biology, 2005
This work seeks to verify multi-shot clinical applications of stereotactic radiosurgery with a Le... more This work seeks to verify multi-shot clinical applications of stereotactic radiosurgery with a Leksell Gamma Knife model C unit employing a polymer gel-MRI based experimental procedure, which has already been shown to be capable of verifying the precision and accuracy of dose delivery in single-shot gamma knife applications. The treatment plan studied in the present work resembles a clinical treatment case of pituitary adenoma using four 8 mm and one 14 mm collimator helmet shots to deliver a prescription dose of 15 Gy to the 50% isodose line (30 Gy maximum dose). For the experimental dose verification of the treatment plan, the same criteria as those used in the clinical treatment planning evaluation were employed. These included comparison of measured and GammaPlan calculated data, in terms of percentage isodose contours on axial, coronal and sagittal planes, as well as 3D plan evaluation criteria such as dose-volume histograms for the target volume, target coverage and conformity indices. Measured percentage isodose contours compared favourably with calculated ones despite individual point fluctuations at low dose contours (e.g., 20%) mainly due to the effect of T2 measurement uncertainty on dose resolution. Dose-volume histogram data were also found in a good agreement while the experimental results for the percentage target coverage and conformity index were 94% and 1.17 relative to corresponding GammaPlan calculations of 96% and 1.12, respectively. Overall, polymer gel results verified the planned dose distribution within experimental uncertainties and uncertainty related to the digitization process of selected GammaPlan output data.
Physics in Medicine and Biology, 2005
This work describes an experimental procedure with potential to assess the overall accuracy assoc... more This work describes an experimental procedure with potential to assess the overall accuracy associated with gamma knife clinical applications, from patient imaging and dosimetry planning to patient positioning and dose delivery using the automated positioning system of a Leksell Gamma Knife model C. The VIPAR polymer gel-MRI dosimetry method is employed due to its inherent three-dimensional feature and linear dose response over the range of gamma knife applications. Different polymer gel vials were irradiated with single shot gamma knife treatment plans using each of the four available collimator helmets to deliver a maximum dose of 30 Gy. Percentage relative dose results are presented not only in the form of one-dimensional profiles but also planar isocontours and isosurfaces in three dimensions. Experimental results are compared with corresponding Gammaplan treatment planning system calculations as well as acceptance test radiochromic film measurements. A good agreement, within the experimental uncertainty, is observed between measured and expected dose distributions. This experimental uncertainty is of the order of one imaging pixel in the MRI gel readout session (<1 mm) and allows for the verification of single shot gamma knife applications in terms of acceptance specifications for precision in beam alignment and accuracy. Averaging net R(2) results in the dose plateau of the 4 mm and 18 mm collimator irradiated gel vials, which were MR scanned in the same session, provides a crude estimate of the 4 mm output factor which agrees within errors with the default value of 0.870.
Physics in Medicine and Biology, 2005
Despite its advantages, the polymer gel-magnetic resonance imaging (MRI) method has not, as yet, ... more Despite its advantages, the polymer gel-magnetic resonance imaging (MRI) method has not, as yet, been successfully employed in dosimetry of low energy/low dose rate photon-emitting brachytherapy sources such as 125I or 103Pd interstitial seeds. In the present work, two commercially available 125I seed sources, each of approximately 0.5 U, were positioned at two different locations of a polymer gel filled
International Journal of Radiation Applications and Instrumentation. Part C. Radiation Physics and Chemistry
The ability of polymer to crosslink or exposure to radiation is frequently represented by a G val... more The ability of polymer to crosslink or exposure to radiation is frequently represented by a G value, the number of crosslinks per 100 eV absorbed. Several methods are available for its determination, the most frequent being the dose D s required to form an incipient network since (with many systems) this corresponds to one crosslinked unit per weight average molecular (~ = 1). Its determination therefore depends on a knowledge of the molecular weight of the starting polymer. An alternative method, far less frequently used, is to measure the degree of swelling of a crosslinked network. This involves a knowledge of the Flory-Huggins interaction parameter/~ and of the initial number average M,¢0). However if the concentration V, of effective chains (deduced from swelling) is plotted against dose D, the slope gives G (X) directly, independent of M.¢0). This applies only when the system is very largely crosslinked. It may also be used to determine G(X) even when starting from the monomer itself (i.e. combining polymerization and crosslinking). It is shown that, for a series of polymers, irradiated either as liquids or in solution, the theoretical relation between swelling and crosslink density is followed, and the G(X) values derived from swelling compare well with those given in the literature, and based on gel fraction.
International Journal of Radiation Applications and Instrumentation. Part C. Radiation Physics and Chemistry
ABSTRACT
International Journal of Radiation Applications and Instrumentation. Part C. Radiation Physics and Chemistry
International Journal of Radiation Applications and Instrumentation. Part C. Radiation Physics and Chemistry
Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms
Irradiation of dilute, deoxygenated aqueous solutions of hydrophilic polymers with high-dose puls... more Irradiation of dilute, deoxygenated aqueous solutions of hydrophilic polymers with high-dose pulses of fast electrons leads to the simultaneous formation of many radicals on each polymer chain. These radicals undergo mainly intramolecular recombination. In this way internally crosslinked macromolecules ± nanogels ± are formed. Current data on poly(vinyl pyrrolidone) show that during this process the weight-average molecular weight remains almost constant, but there is a pronounced decrease in the radius of gyration of macromolecules, an eect expected for the formation of compact, internally crosslinked structures.
Eurasian Chemico-Technological Journal
Complex formation between bovine serum albumin and water-soluble synthetic cationic polyelectroly... more Complex formation between bovine serum albumin and water-soluble synthetic cationic polyelectrolyte poly[2-methacryloyloxy)ethyl]trimethyl ammonium chloride has been studied in aqueous solutions by turbidimetric and viscometric methods. It was found that the structure of polycomplex is compact and its stability strongly depends on the environment. Formation of insoluble polycomplexes is observed in solutions with low ionic strength and pH, higher than 5.0. This pH value corresponds to the isoelectric point of the protein, so at lower pH the biopolymer macromolecules gain the positive charge and not able to be bound by the positively charged macromolecules of poly[2-methacryloyloxy)ethyl]trimethyl ammonium chloride. An increase of pH within 5.0-11.0 leads to further stabilization of polycomplex because of appearance of additional negative charges on biomacromolecules, caused by ionization of acidic groups. It was found that the main forces, which are responsible for the complexation,...
Radiation Physics and Chemistry, 2017
Farmacja Polska, Jun 1, 2008
Radiation Physics and Chemistry, Mar 1, 2002
... Piotr Ula ski Corresponding Author Contact Information , E-mail The Corresponding Author , S ... more ... Piotr Ula ski Corresponding Author Contact Information , E-mail The Corresponding Author , S awomir Kad ubowski and Janusz M. Rosiak. ... (2)), α=0.73 (best fit), initial average number of radicals per chain Z RO =18. View Within Article. ...