[Show abstract][Hide abstract] ABSTRACT: Aim
Investigation of the bystander effect in Chinese Hamster Ovary cells (CHO-K1) co-cultured with cells irradiated in the dose range of 0.1–4 Gy of high LET 12C ions and X-rays.
The radiobiological effects of charged heavy particles on a cellular or molecular level are of fundamental importance in the field of biomedical applications, especially in hadron therapy and space radiation biology.
Materials and methods
A heavy ion 12C beam from the Heavy Ion Laboratory of the University of Warsaw (HIL) was used to irradiate CHO-K1 cells. Cells were seeded in Petri dishes specially designed for irradiation purposes. Immediately after irradiation, cells were transferred into transwell culture insert dishes to enable co-culture of irradiated and non-irradiated cells. Cells from the membrane and well shared the medium but could not touch each other. To study bystander effects, a clonogenic survival assay was performed.
The survival fraction of cells co-cultured with cells irradiated with 12C ions and X-rays was not reduced.
The bystander effect was not observed in these studies.
Reports of Practical Oncology and Radiotherapy 05/2014;
[Show abstract][Hide abstract] ABSTRACT: Dynamics of the electron spin in the Photoelectric Effect was studied in time-reversal via the process of Radiative Recombination. For this the photorecombination into an excited state of an ion and its subsequent radiative decay was observed. Pairs of correlated photons were detected in conicidence. Such an observation is the first of its kind for the initial ion as heavy as bare uranium.
Journal of Physics Conference Series 04/2014; 488(8):082023.
[Show abstract][Hide abstract] ABSTRACT: The chemotherapy and photon radiotherapy are the most often applied methods in treatment of the cancer diseases because of their effectiveness and high cure rates. Apart from eligible destruction of the tumour, one of the side effects of these treatment methods is possible modification of main and trace element concentration in different human tissues and fluids. In this paper, the copper (Cu) level in human serum was determined by total reflection X-ray fluorescence method in 142 chemotherapy patients and in 44 healthy persons being a control group. The Cu concentration in the chemotherapy group was found to be on the level 1.78 ± 0.909 mg/L, while in the control group, it was 1.08 ± 0.551 mg/L. Performed measurements allowed for calculation of the parameters of copper concentration distribution (mean value, standard deviation, median) for both analysed groups. The theoretical nature of the concentration distribution was tested and found as a log-normal distribution (control group) and a log-stable distribution (chemotherapy group). The copper concentration distributions for both studied group were statistically compared using Kolmogorov-Smirnov test, and the conclusion was that the distributions are statistically different. Serum Cu levels were significantly higher in the chemotherapy group than in the control group. Taking into account the results for the control group, the copper concentration reference quantile ranges in human serum were obtained. The values of the mean, median and other quantiles determined in this case can be applied in two-group comparison studies. The obtained results can be used as a diagnostic tool for chemotherapy patients.
Biological trace element research 02/2014; · 1.92 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: The impact of irradiated cells and their progeny on non-irradiated cells
was investigated. The experimental set up with a horizontal heavy ion beam
designed for radiobiological research at the Heavy Ion Laboratory of the
University of Warsaw (HIL) was used. Chinese Hamster Ovary (CHO-K1)
cells were irradiated in the dose range 0.1 Gy–4 Gy of high Linear Energy
Transfer (LET) 12C ions and X rays. To examine the bystander effect,
irradiated and non-irradiated cells were co-cultured in special Petri dishes
with inserts. The cells shared medium but could not touch each other. To
assess the biological response in individual cells a micronucleus assay was
Acta Physica Polonica Series B 01/2014; 45:553. · 1.01 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: One- and few-electron ions traditionally serve as an important testing ground for fundamental atomic structure theories and for the effects of QED, relativity and electron correlation. In the domain of high nuclear charges, new opportunities open up for precise testing and consolidating of the present understanding of the atomic structure in the regime of extreme electromagnetic fields. In this review, the current progress in experimental investigations of the heaviest H- and He-like systems at GSI Darmstadt is presented together with the planned future developments.
[Show abstract][Hide abstract] ABSTRACT: The interpretation of L-shell satellites and hypersatellites for Lα1,2 (L3→M4,5) and Lβ1 (L2→M4) x-ray transitions in zirconium multiply ionized by oxygen and neon ions is reported. The x-ray spectra were measured with a high-resolution von Hamos spectrometer and interpreted in terms the relativistic multi-configuration Dirac-Fock (MCDF) calculations. The ionization probabilities of L- and M-shell derived from the data are compared with the predictions of the semiclassical approximation (SCA) calculations.
Journal of Physics Conference Series 12/2009; 194(15):152012.
[Show abstract][Hide abstract] ABSTRACT: We report the results of the x-ray radiative recombination (RR) experiment at the electron cooler of the ESR storage ring performed, for the first time, for detuned (off-cooling) electron energies. In this experiment the recombination of stored, decelerated bare uranium ions with electrons in the energy range 0–1000 meV was studied by observing K-RR x-ray photons emitted from direct radiative recombination to the lowest n=1 state. In this way the RR process was studied in a state selective manner for several off-cooling electron energies. The measured dependency of the recombination rate on the relative electron energies for K-shell RR x-ray photons are compared with the predictions of both nonrelativistic and fully relativistic calculations for the radiative recombination. A role of the relativistic effects, which contribute substantially for higher relative electron energies, are discussed. Strong enhancement of the recombination rate is observed for the the zero relative electron energy (cooling condition) for the K-shell.
The European Physical Journal Special Topics 01/2009; 169(1). · 1.80 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: To determine the relationship between the relative biological effectiveness (RBE) for cell inactivation and linear energy transfer (LET) in the Bragg peak region of (12)C and (20)Ne ions.
Chinese hamster ovary (CHO-K1) cells were exposed to high LET (12)C (33.2 MeV, 20.3 MeV, 9.1 MeV at cell entrance) and (20)Ne ions (56.2 MeV, 34.7 MeV, 15 MeV at cell entrance) and to low LET x-rays. Technical details of the irradiation facility are presented which is based on the Monte Carlo simulation of the lateral spread of heavy ions as a result of the multiscattering small-angle process in physical conditions of the experimental set-up.
RBE has been measured for LET values close to the Bragg peak maximum, i.e., 440-830 keV/microm for (12)C and for 1020-1600 keV/microm for (20)Ne ions. RBE values at several levels of survival were estimated and were found to decrease with increasing LET. The inactivation cross sections were calculated from the final slope of dose-response curves and were found to increase with increasing LET.
The RBE decreases with increasing LET in the range between 440 and 1600 keV/microm for the two types of radiations forming a single line when plotted together, pointing towards LET as the single determinant of RBE. The inactivation cross section describing the killing efficiency of a single particle at the end of particle range comes close to the size of the cell nucleus.
International Journal of Radiation Biology 11/2008; 84(10):821-9. · 1.84 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: The coupling and binding effects have been studied in L-subshell ionization of heavy Au, Bi, Th, and U atoms by an impact of S28iq+ ions in the energy range of 8.5–36.0 MeV. The measured L x-ray spectra were analyzed taking into account the multiple ionization effects in outer M and N shells. The L-subshell ionization cross sections have been obtained from measured x-ray production cross sections using the L-shell fluorescence and Coster-Kronig yields which were modified for a reduced number of electrons and closed Coster-Kronig transitions in the multiply ionized atoms. The results are compared with the available calculations, which are based on the semiclassical approximation (SCA) as well as the plane-wave Born approximation (PWBA). We demonstrate that for silicon ion impact these theoretical approaches have to be modified to include the L-subshell coupling effect using the “coupled subshell model” (CSM) as well as the saturation of the binding effect at the united atom limit. The calculations modified for both effects are in much better agreement with the data. In particular, an order-of-magnitude improvement of agreement between the data and the SCA-CSM calculations including the binding-saturation effect is reported for low-energy Si ions for the L2-subshell. The results are also compared with the predictions of the PWBA based ECPSSR and ECUSAR theories accounting for the energy-loss (E), Coulomb-deflection (C), and relativistic (R) effects treating the binding effect within the perturbed stationary state (PSS) approximation with correction for the binding-saturation effect introduced to describe the united-atom and separated-atom (USA) limits.
[Show abstract][Hide abstract] ABSTRACT: The first experimental results of a high-resolution study of Th and U Lγ-X-rays induced in collisions with 230 MeV and 360 MeV oxygen ions, undertaken to investigate the dynamics of the multiple ionization in M-, N- and O-shells and the structure of M- and N-shell X-ray satellites, are reported. The measurements were performed using the transmission curved- crystal spectrometer installed in DuMond geometry. An instrumental resolution of about 10 eV was achieved for Lγ (L-N,O) X-ray transitions, allowing clear separation of M-shell X-ray satellites for Th and U. Moreover, the N-shell satellite structure in the Lγ6 (L2-O4) X-ray transition was observed for 360-MeV O ion impact on a thorium target. This, to our knowledge, is the first observation of this kind. Other observed Lγ X-ray diagram lines are shifted and widened, with respect to the photoinduced X-ray spectra excited by an X-ray tube, due to the unresolved N-shell and, probable the O-shell, satellite structure.
Physica Scripta 08/2006; 2001(T92):382. · 1.03 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: L shell x-ray production cross sections of Au and Bi atoms generated by Si-ions with energy range of 8.5-36.0 MeV have been measured. The L subshell ionization cross sections have been obtained from Lα1,2, Lγ1, and Lγ2,3 transitions using the L shell fluorescence and Coster-Kronig (CK) yields modified by the multiple ionization effects. The results are compared with the predictions of the ECPSSR theory (perturbed-stationary-state (PSS) with energy-loss (E), Coulomb deflection (C), and relativistic (R) corrections) and the semiclassical approximation (SCA) calculations for the united atoms case (UA), and their modification for the L subshell couplings within the "coupled-subshell model" (CSM).