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Wyszukujesz frazę "87.50.-a" wg kryterium: Temat


Wyświetlanie 1-15 z 15
Tytuł:
Investigating Mechanisms of Radiation-Induced DNA Damage Using Low-Energy Photons
Autorzy:
Folkard, M.
Prise, K. M.
Powiązania:
https://bibliotekanauki.pl/articles/2044651.pdf
Data publikacji:
2006-03
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
87.50.-a
Opis:
Central to any mechanistic biophysical model of radiation damage to DNA is the relationship between the amount and distribution of energy deposited in the DNA helix and the subsequent production of DNA damage. It is now clear from a number of studies that the minimum energy required to produce bond breaks in DNA is significantly lower than might be expected. For example, some biophysical models have assumed that it takes several 10s of eV to produce a double-strand break in DNA. However, using low-energy photons, we have shown that energy depositions as low as 7 eV can induce double-strand break and that this is enhanced when the DNA is hydrated, showing that free radical damage is also important.
Źródło:
Acta Physica Polonica A; 2006, 109, 3; 265-271
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Single Proton Hit Facility at the IFJ PAN in Cracow
Autorzy:
Polak, W.
Lekki, J.
Veselov, O.
Stachura, Z.
Styczeń, J.
Powiązania:
https://bibliotekanauki.pl/articles/2044772.pdf
Data publikacji:
2006-03
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
87.50.Gi
87.50.-a
Opis:
This work presents the final development stage and optimization results of the single proton hit facility in Cracow. The setup parameters: proton beam energy 2 MeV, hit resolution 30μm, intensity ≈1000 proton/s, proton registration efficiency 100%, blanking efficiency 99.8%. On-line observation allows targeting cells inside a Petri dish mounted at a 3D precise moving stage. To target a particular cell a semiautomatic cell visualization and recognition system is used.
Źródło:
Acta Physica Polonica A; 2006, 109, 3; 417-420
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Understanding Radiation Damage to Cells Using Microbeams
Autorzy:
Folkard, M.
Prise, K. M.
Shao, C.
Gilchrist, S.
Schettino, G.
Michette, A. G.
Vojnovic, B.
Powiązania:
https://bibliotekanauki.pl/articles/2044649.pdf
Data publikacji:
2006-03
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
41.75.Ak
87.50.-a
Opis:
Cellular micro-irradiation techniques provide unique experimental opportunities for understanding how ionizing radiation interacts with living cells and tissues. Using microbeams, it is possible to deliver precise doses of radiation to selected individual cells, or sub-cellular targets in vitro. This technique continues to be applied to the investigation of a number of phenomena currently of great interest to the radiobiological community. In particular, it is the study of so-called "non-targeted" effects (where cells are seen to respond indirectly to ionizing radiation) that are benefiting most from the use of microbeam approaches.
Źródło:
Acta Physica Polonica A; 2006, 109, 3; 257-264
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The GSI Heavy Ion Microbeam: A Tool for the Investigation of Cellular Response to High LET Radiations
Autorzy:
Barberet, Ph.
Heiss, M.
Du, G.
Fischer, B. E.
Taucher-Scholz, G.
Powiązania:
https://bibliotekanauki.pl/articles/2044671.pdf
Data publikacji:
2006-03
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
41.75.Ak
87.50.-a
Opis:
Since the mid 1990's, an increasing number of charged particle microbeams have been designed to deliver a preset number of ions to individual living cells with the micron resolution. These tools provide a powerful technique to investigate the cellular response to low doses of radiations. During the last years, the single ion hit facility in operation on the GSI microbeam since 1987 has been upgraded for the irradiation of individual living cells in vitro. This setup presents two main peculiarities compared to the microbeams used up to now for cell irradiation. First, the beam's micrometric size is obtained by magnetic focusing and not by a simple collimation. This allows obtaining a smaller beam spot, a better defined linear energy transfer, and a high irradiation throughput. Then, the GSI microbeam is able to focus ions from carbon to uranium with energies between 1.4 MeV/u to 11.4 MeV/u. The range of accessible linear energy transfer is thus considerably extended compared to light ions microbeam in operation today. The design of the GSI microbeam is described, including the beam control, the online cell localisation, the cell dish designed specifically for microbeam irradiation, and the cell irradiation procedures. Experimental tests performed to check the global aiming accuracy as well as the first cellular irradiations are presented.
Źródło:
Acta Physica Polonica A; 2006, 109, 3; 329-334
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effects of 60 MeV Protons and 250 kV X-Rays on Cell Viability
Autorzy:
Miszczyk, J.
Panek, A.
Rawojć, K.
Swakoń, J.
Prasanna, P.
Rydygier, M.
Gałaś, A.
Powiązania:
https://bibliotekanauki.pl/articles/1398817.pdf
Data publikacji:
2016-02
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
87.50.-a
87.53.-j
87.53.Bn
Opis:
Particle radiotherapy such as the one using proton beams, provides a successful treatment approach in many cancer types. However, the cellular and molecular mechanisms by which proton irradiation induces cell death, particularly in a human peripheral blood lymphocyte model has not been examined in detail. Comparative studies of the biological effects, such as cell death, of particle therapy versus conventional X-rays treatment are of utmost importance. Here, we compared the viability of human peripheral blood lymphocyte following in vitro irradiation with protons (therapeutic 60 MeV proton beam) and photon beam (250 kV, X-rays), by applying separate doses within the range of 0.3-4.0 Gy. Cell viability was assessed 1 and 4 h after irradiation with protons and X-rays by the FITC-Annexin V labelling procedure (Apoptotic & Necrotic & Healthy Cells Quantification Kit, Biotium). Results showed that irradiation with both radiation types reduced the number of viable cells in a dose-dependent manner, as assessed as a function of the duration of post-irradiation time. Protons proved more fatal to the cells treated than X-ray photons. This demonstrates a difference in cell viability after irradiation with protons and photons in a human peripheral blood lymphocyte model.
Źródło:
Acta Physica Polonica A; 2016, 129, 2; 222-225
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effect of Pulsed High-Voltage Stimulation οn Pholiota Nameko Mushroom Yield
Autorzy:
Takaki, K.
Yamazaki, N.
Mukaigawa, S.
Fujiwara, T.
Kofujita, H.
Takahasi, K.
Narimatsu, M.
Nagane, K.
Powiązania:
https://bibliotekanauki.pl/articles/1807916.pdf
Data publikacji:
2009-06
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
87.50.-a
52.90.+z
82.39.Rt
Opis:
A pulsed high voltage was applied to logs for mushroom cultivation to investigate an effect of pulse high voltage on mushroom growth. Inductive energy storage system was utilized to construct a pulsed power generator with compact size. Copper fuse of 0.03 mm diameter was used as an opening switch to interrupt large circuit current in short time. The voltage charged in primary energy storage capacitor was multiplied using secondary energy storage inductor. The output voltage of the pulsed power generator was 120 kV with 100 ns pulse width at 14 kV charging voltage of 0.22 μF primary energy storage capacitor and 15 μH secondary energy storage inductor. This pulsed high voltage was applied to 90 cm length logs inoculated Pholiota nameko fungus. The yield of Pholiota nameko mushrooms was successfully improved with the pulse voltage stimulation. The total weight of the cropped Pholiota nameko after the pulse voltage stimulation was 6.3 kg for fifteen logs and this value was 1.5 times larger than 4.3 kg of total weight without the stimulation. The number of logs with lower than 0.27 kg cropped Pholiota nameko weight which was an average value for control group was only one in fifteen, whereas four logs in control group showed almost zero weight of cropped Pholiota nameko.
Źródło:
Acta Physica Polonica A; 2009, 115, 6; 1062-1065
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effect of magnetite composite on the amount of double strand breaks induced with X-rays
Autorzy:
Wiecheć, A.
Nowicka, K.
Błażewicz, M.
Kwiatek, W.
Powiązania:
https://bibliotekanauki.pl/articles/1065182.pdf
Data publikacji:
2016-02
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
87.50.-a
87.53.-j
81.05.Mh
81.05.Ni
81.05.Pj
81.05.Qk
75.50.Bb
Opis:
The aim of this study was to find out if polylactide (PLA) modified with magnetite might affect the amount of DNA double strand breaks induced with X-rays. The human osteosarcoma cells (MG63) were seeded on the polystyrene cell culture dishes (PS), PLA and PLA modified with magnetite substrates. The double strand breaks were analyzed after X-ray irradiation (dose rate 2 Gy/min), in the first day of culturing. The number of double strand breaks increased in the PLA modified with magnetite, for example after 1 Gy of X-rays irradiation, double strand breaks/cell equaled: 24.5 vs. 17.5 and 17.3, for PLA modified with magnetite vs. PLA and PS, p < 0.0003. We conclude that PLA modified with magnetite changed the number of double strand breaks induced with X-rays. However, more research is needed to confirm that such composite might be considered as radiosensitizer in radiotherapy.
Źródło:
Acta Physica Polonica A; 2016, 129, 2; 174-175
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Quantum Cellular Automata: a Short Overview of Molecular Problem
Autorzy:
Tsukerblat, B.
Palii, A.
Clemente-Juan, J.
Suaud, N.
Coronado, E.
Powiązania:
https://bibliotekanauki.pl/articles/1029743.pdf
Data publikacji:
2018-03
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.50.Xx
87.16.A-
Opis:
In this article we summarize the study of the electronic states and electron-vibrational interactions in square-planar molecular entities playing the role of molecular cells in quantum cellular automata (QCA), a promising paradigm of quantum computing. The following issues are shortly discussed: 1) QCA as a paradigm of quantum computing; 2) molecular implementation of QCA; 3) vibronic coupling as the origin of charge trapping, encoding of binary information 4) non-linear cell-cell response; 4) spin-switching in molecular QCA based on mixed-valence cells; 5) multimode dynamic vibronic problem, the symmetry assisted approach.
Źródło:
Acta Physica Polonica A; 2018, 133, 3; 329-335
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Magnetic Heating by Tunable Arrays of Nanoparticles in Cancer Therapy
Autorzy:
Zablotskii, V.
Lunov, O.
Gómez-Polo, C.
Powiązania:
https://bibliotekanauki.pl/articles/1810619.pdf
Data publikacji:
2009-01
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
87.55.D-
87.55.de
89.20.-a
75.50.Tt
Opis:
Detailed knowledge about the temperature distribution achieved in the target area is essential for the development of magnetic hyperthermia treatments. However, the temperature inhomogeneity was found in all local hyperthermia studies. As a consequence of the impossibility of guaranteeing the temperature and thus the thermal dose distribution, hyperthermia is never applied as a single treatment modality. We suggest a model that enables the calculations and optimization of the spatial-time distribution of the temperature in the target volume (i.e. tumor) caused by magnetically heated elements: (i) arrays of clusters of iron oxides magnetite $(Fe_3O_4)$ magnetic nanoparticles, and (ii) arrays of magnetic needles. In order to find the spatial-time temperature distribution in tumor, the bioheat transfer equation is solved for the two above-mentioned arrays of magnetically heated sources embedded in the tumor. The temporal and spatial temperature distributions were calculated with regard to the effect of blood perfusion in the tumor. It is shown that a matrix of magnetic micro-needles injected in the tumor could provide rather uniform tumor heating with the center-edge temperature difference smaller than 3°C at any times during the magnetic hyperthermia treatments. The temperature profiles can be suitably adjusted by a proper choice of the magnetic nanoparticles arrangement.
Źródło:
Acta Physica Polonica A; 2009, 115, 1; 413-417
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Magnetic Properties of Encapsulated Magnetite in PLGA Nanospheres
Autorzy:
Koneracká, M.
Závišová, V.
Timko, M.
Kopčanský, P.
Tomašovičová, N.
Csach, K.
Powiązania:
https://bibliotekanauki.pl/articles/1813943.pdf
Data publikacji:
2008-01
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
71.20.Rv
75.50.Mm
87.83.+a
Opis:
In this study, the biocompatible magnetic fluid was encapsulated in biodegradable polymer PLGA (poly D, L/lactide-co-glycolide acid) by the nanoprecipitation method. We characterized these spheres in terms of morphology, magnetite content and magnetic properties. The results showed good encapsulation with magnetite content 22wt% and magnetization 3.4 mT. The transmission electron microscopy and scanning electron microscopy images showed that magnetic particles have almost a spherical shape with approximate size 250 nm. Infrared spectroscopy and thermogravimetric analysis measurements were used to confirm incorporation of magnetic particles into the PLGA polymer.
Źródło:
Acta Physica Polonica A; 2008, 113, 1; 595-598
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The Rule for Evolution of Cooperation in Quantum Games
Autorzy:
Sun, Z.
Powiązania:
https://bibliotekanauki.pl/articles/1807768.pdf
Data publikacji:
2009-08
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
02.50.Le
03.67.-a
87.23.-n
Opis:
Cooperation is essential to biological organizations and human society. In this paper, the conditions of dilemmas resolving by quantum strategies in the three games, Prisoners' Dilemma, Chicken Game and Stag Hunt, are presented. The rule for the evolution of cooperation in general quantum games, b/c > $coth^{2}γ$, is put forward. The formation of the rule is similar to those of the five rules in the classical game theory summarized by Nowak. b/c is still the benefit-to-cost ratio of the altruistic act, while γ is a measure for the game's entanglement. The rule is the prerequisite for the realization of cooperation in quantum games.
Źródło:
Acta Physica Polonica A; 2009, 116, 2; 135-140
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The Influence of the Vibroacoustic Environment Conditions on Functional Stability of Drivers
Autorzy:
Damijan, Z.
Powiązania:
https://bibliotekanauki.pl/articles/1537357.pdf
Data publikacji:
2010-07
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
89.40.-a
43.80.-n
43.80.-p
87.50.Y-
Opis:
Despite new technological solutions and attempts to improve the working conditions during the operation of vehicles, city bus drivers are still exposed to negative impacts of noise and vibrations. This research project was undertaken in response to the lack of holistic analyses of the environmental factors that might impact on the city bus drivers at work. No extensive major research was done to investigate the influence of the conditions at work on functional stability of bus drivers and basic physiological parameters of the human body (systolic and diastolic pressure, pulse rate, temperature in the ear channel, loading of postural muscles, blood circulation determined with the use of a thermovision camera, fatty tissue content, body mass and physical condition (squeezing and pressing exercises). the main purpose of this research program was to show the impacts that the conditions at work might have on bus drivers or to demonstrate that these impacts do no exist.
Źródło:
Acta Physica Polonica A; 2010, 118, 1; 23-26
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The Influence of General Low Frequency Vibration on Posture Stability
Autorzy:
Damijan, Z.
Uhryński, A.
Powiązania:
https://bibliotekanauki.pl/articles/1490372.pdf
Data publikacji:
2012-01
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
89.40.-a
07.10.-h
46.32.+x
87.50.Y-
Opis:
The work presents the research and analysis concerning general low frequency vibration and its influence on posture stability. The research was conducted in two phases: a group exposed to vibration - August 2006, a control group: November 2006 in Krynica-Zdrój. An exposed group (29 participants/took part in 19 training sessions, each lasting 20 min, of low frequency vibration, standing position) applied to each participant at fixed time of the day. The low frequency vibration amplitude was 4 mm, while the frequency was 3.5 Hz. Before and after the session the posturographic examination of posture stability was conducted. The control group (33 participants) also took part in 19 everyday 20 min sessions with no vibrations and only measurements conducted. The results were analyzed concerning statistics using Statistica. For the sake of the analysis the significance level was p = 0.05, the parametric t-test and the nonparametric Kolmogorov-Smirnov tests were used for two groups of independent variables. Having conducted the research and analysis, one can state that 20 min exposure to low frequency vibration results in significant changes in posture stability and 19 day long vibration training changes significantly the posture stability among the participants. The observed changes were of positive nature. The work introduces research on the possibility of using low-frequency vibration to improve human stability. The results presented concern biophysics in rehabilitation of posture stability and are not often met in specialist literature.
Źródło:
Acta Physica Polonica A; 2012, 121, 1A; A-028-A-031
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Impact of Vibroacoustic Climate on Driver's Postural Stability for Eyes Closed in Driver's Cabin
Autorzy:
Damijan, Z.
Skrzyniarz, S.
Kwaśniewski, J.
Powiązania:
https://bibliotekanauki.pl/articles/1504430.pdf
Data publikacji:
2011-06
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
89.40.-a
07.10.-h
46.32.+x
87.50.Y-
Opis:
Several levels of the nervous system are responsible for stability of the vertical position in humans. Three basic inputs are involved: atrial, visual and proprioceptive as well as mechanoreceptors present in the skin. Signals from these inputs control the body posture and its orientation with respect to internal and external reference systems. External systems are formed based on the gravitation field and visual stimuli. Internal systems are generated in the central nervous system by polymodal representations, also referred to as body schema. Some of environmental factors of driver's work place could disturb postural stability. Almost all vehicles are according with actual norms and directives. We investigate how normal week of work has impact on postural stability in new city buses. We concentrate on postural stability for closed eyes. In this paper results of investigation were presented.
Źródło:
Acta Physica Polonica A; 2011, 119, 6A; 1073-1076
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Silver Nanoparticles as Enhancing Substrates for Raman and Fluorescence Spectroscopy
Autorzy:
Cyrankiewicz, M.
Wybranowski, T.
Kruszewski, S.
Powiązania:
https://bibliotekanauki.pl/articles/1196708.pdf
Data publikacji:
2014-04
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
33.20.Fb
33.20.Kf
32.50.+d
61.46.Df
73.20.Mf
78.67.Bf
87.83.+a
Opis:
The enhancing properties of silver nanoparticles in surface-enhanced Raman scattering (SERS) and metal-enhanced fluorescence (MEF) are studied in this work. The obtained results confirm that the partial aggregation of nanoparticles leads to a great increase of Raman scattering cross-section but there are significant differences in SERS-activity of colloidal silver treated with various aggregating compounds. The differences are interpreted through the analysis of both experimental and computational results. The same silver colloid covered with silica shell preventing the fluorescence quenching makes possible a several-fold increase in fluorescence emission. The effect strongly depends on thickness of the outer layer of nanoparticles. Geometrical parameters of nanoparticles (radius or radius and thickness of the adsorption layer in core-shell systems) are determined on the basis of the dynamic light scattering (DLS) data and extinction spectra analysis.
Źródło:
Acta Physica Polonica A; 2014, 125, 4A; A-11-A-15
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-15 z 15

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