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Tytuł:
Effect of X-ray Irradiation on Articular Cartilage Mechanical Properties
Autorzy:
Cicek, E.
Powiązania:
https://bibliotekanauki.pl/articles/1398818.pdf
Data publikacji:
2016-02
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
87.85.G-
Opis:
A load bearing tissue found at the ends of articulating bones, the articular cartilage provides low friction surfaces for efficient movement. Its mechanical properties are determined by the structure and composition of type II collagen, proteoglycans and interstitial fluid. This work investigates the effects of X-ray irradiation, previously shown to affect the biological properties of the articular tissue, on mechanical properties of articular cartilage using polarized light microscope for imaging and compressive modulus test applied to articular cartilage to determine the effects of the ionizing radiation on mechanical properties. According to the test results, the relaxation time is significantly longer in control than X-ray exposed samples, while the force is much higher showing that the X-ray irradiation causes the reduction in the stiffness of articular cartilage.
Źródło:
Acta Physica Polonica A; 2016, 129, 2; 200-202
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Morphological Variations of Chondrocytes in Bovine Articular Cartilage Using Confocal Laser Scanning Microscopy
Autorzy:
Çıçek, E.
Arikanoğlu, A.
Powiązania:
https://bibliotekanauki.pl/articles/1197654.pdf
Data publikacji:
2014-04
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
87.85.G-
Opis:
Articular cartilage is a highly organized avascular tissue, a matrix consisting of a three-dimensional meshwork of type II collagen fibrils and proteoglycans. To understand the effects of the alteration in chondrocyte shape in response to physiological load in local mechanical properties and, thus, to contribute to experimental load studies, we studied variation of the natural load induced deformations in chondrocytes among five different regions from bovine articular cartilage samples using confocal laser scanning microscopy imaging methods. The morphological differences of the chondrocyte shape, orientation and circularity in articular cartilage were measured. The chondrocytes were observed to be smoother in more loaded regions to the center of the cartilage.
Źródło:
Acta Physica Polonica A; 2014, 125, 4; 898-901
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Biological Action in and out of the Water Window
Autorzy:
Vyšín, L.
Davídková, M.
Wachulak, P.
Fiedorowicz, H.
Bartnik, A.
Krůs, M.
Kozlová, M.
Skála, J.
Dostál, J.
Dudžák, R.
Juha, L.
Powiązania:
https://bibliotekanauki.pl/articles/1029783.pdf
Data publikacji:
2018-02
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
87.14.G-
52.38.-r
Opis:
This study is dealing with the difference of radiation chemical yields of single and double strand breaks induced in plasmid DNA by photons inside and outside of the soft X-ray water window, i.e., in the wavelength range from 2.28 nm to 4.88 nm. Photons were generated by various plasma sources providing nanosecond and sub-nanosecond pulses of extreme ultraviolet, soft X-ray and X-ray radiation. DNA strand breaks were determined by agarose gel electrophoresis. Higher radiation chemical yields of both single and double strand breaks were found using picosecond and nanosecond sources of extreme ultraviolet and X-ray radiation.
Źródło:
Acta Physica Polonica A; 2018, 133, 2; 236-238
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Environmental Gamma Dose Evaluation During Explosive Materials Analysis by PGNAA Technique Using MCNPX Code
Autorzy:
Nasrabadi, M.
Omidi, S.
Powiązania:
https://bibliotekanauki.pl/articles/1401224.pdf
Data publikacji:
2015-04
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
87.52.-g
61.80.-x
78.70.-g
Opis:
Increased use of radiation in medicine, industry, and laboratories, requires safe conditions to be provided for its optimal use. One of the cases in which people are exposed to radiation, is during the detection of explosive materials by PGNAA method. Therefore, external dosimetry is necessary for workplaces where the method is used. In this study, Monte Carlo simulation program, MCNPX has been used to simulate gamma dose in the environment during the detection of explosive materials by PGNAA method. The simulated results were validated practically. The results indicate a good agreement between the simulated and measured data. The study demonstrated that MCNPX code can be used effectively for simulating gamma dose in various environments.
Źródło:
Acta Physica Polonica A; 2015, 127, 4; 961-964
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Objectification of Diagnostic Symptoms in Examination of Nervous System Damage by Static Interactions and Kinematic Parameters of Ankle Joint
Autorzy:
Nitkiewicz, Sz.
Śmieja, M.
Gogolewski, T.
Majchrowski, A.
Grabarczyk, Ł.
Maksymowicz, W.
Powiązania:
https://bibliotekanauki.pl/articles/1197514.pdf
Data publikacji:
2014-04
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
87.85.G-
87.85.Ox
87.85.Tu
Opis:
Current diagnostics of patients' condition as well as assumed effects of the used medical diagnostic methods are a significant part of every medical treatment. The process of continuous gathering experience and comparing it with current knowledge leads to development of medical sciences and still growing effectiveness in practice. Numerous relations between particular human body systems and their interactions are very important for fast and precise diagnosis. In the paper, evaluation of the effects of neurosurgical procedures expressed as improvement of mechanical parameters of skeleton muscle system have been considered. The approach presented in the paper assumes description of results in terms of common physical units.
Źródło:
Acta Physica Polonica A; 2014, 125, 4A; A-27-A-30
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effect of the Fixation Patterns on Magnetic Characteristics of Amorphous Glass-Coated Sensoric Microwires
Autorzy:
Hudak, R.
Varga, R.
Hudak, J.
Praslicka, D.
Blazek, J.
Polacek, I.
Klein, P.
Powiązania:
https://bibliotekanauki.pl/articles/1202355.pdf
Data publikacji:
2014-07
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
87.85.G-
87.85.fk
85.70.Ay
Opis:
Some of the frequent reasons of titanium implant failures in human body are incorrect biomechanical interactions within the tissue-implant interface and inflammatory processes arising around the implant's application area. For both processes, it is crucial to locate them and intervene in time. One of the monitoring possibilities of the mentioned processes is the application of amorphous glass-coated sensoric microwires (AGCSM). Magnetic characteristics of these microwires are influenced by both mechanical tension (magnetoelastic interaction of the magnetic moment with mechanical stress) and by temperature (different coefficient of thermal expansion of the metal core and glass coating). The key task, in order to change the magnetic characteristics of AGCSM from both clinical and scanning point of view, appears to be the fixation pattern of AGCSM in the implant's body. The presented study shows the impact of four types of AGCSM fixation patterns (at one ending, at both endings, in the middle and along the entire length) on the thermal response process tested in laboratory conditions. The obtained results will enable to establish the AGCSM fixation methodology in the implant's body in order to achieve optimal output temperature parameters form the implant and the tissue-implant interface by magnetic contactless measurements.
Źródło:
Acta Physica Polonica A; 2014, 126, 1; 417-418
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Fourier Transform Near Infrared Raman Spectroscopy in Studies on Connective Tissue
Autorzy:
Połomska, M.
Kubisz, L.
Kalawski, R.
Oszkinis, G.
Filipiak, R.
Mazurek, A.
Powiązania:
https://bibliotekanauki.pl/articles/1537548.pdf
Data publikacji:
2010-07
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
78.30.-j
78.30.Jw
61.80.Ed
61.82.Pv
81.05.-t
87.-g
87.93.-j
87.64.K-
Opis:
Studies of tissue such as bones and veins often are carried out by means of microscopic and ultrasonographic methods. Therefore studies of changes caused by pathological or physical factors often are limited to morphological level. Application of Raman spectroscopy permits to associate morphological changes and molecular changes. The paper presents preliminary studies of temperature and ionizing radiation effects on Raman spectra of bone and collagen. Furthermore, effects of pathological factors on Raman spectra of human veins had been studied. It was noticed that heating of bone collagen up to 110°C gives the reversible changes in spectra. In the case of γ-irradiation, any effects were observed up to the dose of 1 MGy on mineral component of bone, whereas the influence on collagen was observed for doses higher than 100 kGy. The Raman spectra of varicose vs. normal veins permit to conclude some important changes observed for veins from chronic venous insufficiency patients.
Źródło:
Acta Physica Polonica A; 2010, 118, 1; 136-140
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Holographic Measurement of Dental Tissue Contraction and Stress, due to Postpolymerization Reaction
Autorzy:
Pantelić, D.
Blažić, L.
Savić-Šević, S.
Murić, B.
Vasiljević, D.
Panić, B.
Belić, I.
Powiązania:
https://bibliotekanauki.pl/articles/2047904.pdf
Data publikacji:
2007-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
42.40.Kw
87.85.G-
87.15.rp
87.10.Kn
Opis:
Polymerization contraction of dental photo-polymer composites induces internal stress, in a tooth cavity. This stress is measured indirectly by, first, holographic determination of tooth deformation, with consequent calculation of stress using finite element method. Real time holographic technique enabled observation of dental deformation in all stages of polymerization. Specially constructed blue-LED light source was used to polymerize photopolymer composite. We have found that polymerization continues even after illumination is over. Consequently, stress is increased, too.
Źródło:
Acta Physica Polonica A; 2007, 112, 5; 1157-1160
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Assessing the Indoor Pollutants Effect on Ornamental Plants Leaves by FT-IR Spectroscopy
Autorzy:
Husti, A.
Cantor, M.
Stefan, R.
Miclean, M.
Roman, M.
Neacsu, I.
Contiu, I.
Magyari, K.
Baia, M.
Powiązania:
https://bibliotekanauki.pl/articles/1398690.pdf
Data publikacji:
2016-01
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
87.14.-g
87.15.B-
87.64.km
92.60.Sz
Opis:
Air pollution has become a mass phenomenon, a major and global problem of modern society, affecting billions of people and environment. People are exposed to various levels of pollutants not just in the outdoor environment, but also in indoors. The quality of life and well-being of employees can be increased by incorporating ornamental plants in the work environment. Among the great variety of plants species able to remove/reduce indoor air pollutants Dracaena deremensis, Sansevieria trifasciata and Ficus elastica were hereby investigated. Their ability to remove chemical pollutants was evaluated in real-life conditions and the changes induced by the environmental stress on the structure and biochemical composition of the plants leaves were evidenced by the Fourier transform infrared spectroscopy. The most pronounced concentration decrease was noticed for the CO₂ (58.33% removed concentration), whereas the mean value of the removed concentration of other chemical pollutants was of ≈ 25%. The Fourier transform infrared spectra analysis revealed that, although the plants are subjected to the chemical pollutants action, they maintain the structure by adjusting their metabolism. A decrease in the overall protein contribution in the amide bands and an increase of the bands assigned to polysaccharide vibrations, illustrate the consequences of the pollution action. Moreover, the chlorophyll presence is evidenced in the IR spectra of all samples by the bands around 1040, 1445, 1620, and 1735 cm^{-1}. The results show that the Fourier transform infrared spectra are an important source of information for the rapid characterization of the chemical structure of the biological systems under environmental stress.
Źródło:
Acta Physica Polonica A; 2016, 129, 1; 142-149
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Neutron Shielding Properties of Concrete and Ferro-Boron
Autorzy:
Sarıyer, D.
Küçer, R.
Küçer, N.
Powiązania:
https://bibliotekanauki.pl/articles/1401975.pdf
Data publikacji:
2015-08
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
02.70.Uu
28.41.Qb
87.52.-g
87.52.Ga
Opis:
The problem of shielding against high-energy neutrons has always attracted a great deal of attention. Neutron shielding requires slowing down energetic neutrons and absorbing with a shield material. Concrete is one of the best known materials for neutron shielding and ferro-boron is described as an alternative shielding material in this study. FLUKA Monte Carlo simulation code was used for the application of shielding calculation. When the simulation results are compared, it is clear that ferro-boron is more effective in neutron shielding than the concrete.
Źródło:
Acta Physica Polonica A; 2015, 128, 2B; B-201-B-202
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Comparative Analysis of KP-HSA Complex by Spectroscopic Methods
Autorzy:
Mąciażek-Jurczyk, M.
Równicka-Zubik, J.
Dyja, R.
Sułkowska, A.
Powiązania:
https://bibliotekanauki.pl/articles/1400125.pdf
Data publikacji:
2013-04
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
33.50.-j
33.50.Dq
82.56.-b
87.14.-g
87.14.E-
Opis:
The main objective of the presented study was to characterize the high (HAS) and low affinity (LAS) binding sites of ketoprofen (KP) in human serum albumin (HSA) structure with the use of spectrofluorescence and proton nuclear magnetic resonance spectroscopy. In vitro fluorescence analysis was used to estimate the effect of KP on the HSA fluorescence. The association constants $K_{a} [M^{-1}]$ of KP-HSA complex in the HAS were determined with the use of Scatchard, Klotz, and Hill analysis. The quenching $K_{Q} [M^{-1}]$ constants were determined on the basis of the Stern-Volmer equation. Binding of ketoprofen to plasma protein was also studied with the use of 8-anilinonapthalene-1-sulfonic acid (ANS) and 5-dimethylaminonaphthalene-1-sulfonic acid (DNSA) as the fluorescence probes in IIIA and IIA subdomains of HSA, respectively. To estimate the cooperativeness in proteins Hill's coefficient $n_{H}$ was used. The analysis of proton nuclear magnetic resonance spectra of KP in the presence of HSA allows us to observe the interactions between aromatic rings of the drug and the rings of amino acids located in the hydrophobic subdomains of the protein on the basis of the changes of chemical shifts Δ σ [ppm] of drug protons resonances. Moreover the $K_{a}$ constants $[M^{-1}]$ of KP-HSA complex in the LAS were determined.
Źródło:
Acta Physica Polonica A; 2013, 123, 4; 673-680
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Computational material analysis of structural and hemodynamic model of coronary stent by CFD/FEA in computer aided mechanical engineering approach
Autorzy:
Karaçal, Ö.
Powiązania:
https://bibliotekanauki.pl/articles/1070469.pdf
Data publikacji:
2016-07
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
87.85.G-
81.70.Bt
82.20.Wt
87.10.Kn
87.15.A-
Opis:
With the development of new technologies, it is very popular to use a coronary stent that is a small mesh tube-shaped medical device deployed to treat narrow or weak arteries as part of a procedure called percutaneous coronary intervention. Several aspects, such as stent design, stent wire type, mechanical and material characteristics of stent have different influences on stent intervention. It has not been reported about what impacts on stent struts by the hemodynamic behavior on stent material and very few numerical studies have considered both the mechanical and hemodynamic impact of stent implementation. Computational simulation method for realization of realistic structural and hemodynamic micro environment model in this research provided valuable results of long-term functional knowledge of stent material behavior that are time consuming and expensive to determine otherwise. Computational fluid dynamics and finite element analysis simulation models were investigated and developed to evaluate engineering properties that affect stent functional attributes. These characteristics are dependences of material properties on blood flow conditions such as structural load, shear-strain rate, radial strength, and wall shear stresses, which need to be scientifically explored. To understand the material (Fe-18Cr-14Ni-2.5Mo as stainless steel 316LVM) mechanical performance of the stent, a finite element analysis simulation model was established when exposed to pulsatile blood pressure. In this study, computational fluid dynamics model was generated to calculate the wall shear stresses and strain distribution in stented vessel carrying blood to heart. The analytical analysis of mechanical and hemodynamic conduct of a stent in this investigation may help for better designs of stent, and provide deeper comprehension to support clinical cardiovascular surgeons and guide potential therapeutic strategies.
Źródło:
Acta Physica Polonica A; 2016, 130, 1; 249-251
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
New Possibilities Opened by Synchrotron Spectromicroscopy in Neurobiology
Autorzy:
De Stasio, G.
Powiązania:
https://bibliotekanauki.pl/articles/1963350.pdf
Data publikacji:
1997-04
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
87.80.+s
87.22.-q
87.64.Lg
Opis:
The use of synchrotron spectromicroscopy in neurobiology is definitely beyond the feasibility-test stage. It produced a large variety of results, mostly concerning the microscopic localization of transition elements in neural cells. We will first describe the experimental technique, then we will discuss some specific experimental examples, including the uptake of cobalt and zinc in rat cerebellar neurons.
Źródło:
Acta Physica Polonica A; 1997, 91, 4; 715-721
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Quantum Foundations of Resonant Recognition Model
Autorzy:
Keković, G.
Raković, D.
Tošić, B.
Davidović, D.
Cosić, I.
Powiązania:
https://bibliotekanauki.pl/articles/1537869.pdf
Data publikacji:
2010-05
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
87.14.E-
87.15.-v
87.15.B-
87.15.Cc
87.15.hp
87.15.kp
Opis:
Biomolecular recognition is an open scientific problem, which has been investigated in many theoretical and experimental aspects. In that sense, there are encouraging results within Resonant Recognition Model (RRM), based on the finding that there is a significant correlation between spectra of the numerical presentation of amino acids in the primary structure of proteins and their biological activity. It has been found through an extensive research that proteins with the same biological function have a common frequency in their numerical spectra. This frequency was found then to be a characteristic feature for protein biological function or interaction The RRM model proposes that the selectivity of protein interactions is based on resonant energy transfer between interacting biomolecules and that this energy, electromagnetic in its nature, is in the frequency range of $10^{13}$ to $10^{15}$ Hz, which incorporates infra-red (IR), visible and a small portion of the ultra-violet (UV) radiation. In this paper, the quantum mechanical basis of the RRM model will be investigated using the solution in the simplified framework of Hückel-like theory of molecular orbits.
Źródło:
Acta Physica Polonica A; 2010, 117, 5; 756-759
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Comparison of Electroporation Threshold for Different Cell Lines in vitro
Autorzy:
Saulis, G.
Saulė, R.
Powiązania:
https://bibliotekanauki.pl/articles/1807913.pdf
Data publikacji:
2009-06
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
87.50.cj
87.80.Fe
87.50.cf
Opis:
The electroporation threshold was compared at various electric pulse durations for three cell lines: two non-tumor cell lines (human erythrocytes and Chinese hamster ovary cells) and one tumor cell line (rat glioma C6 cells). First, the dependences of the fraction of electroporated cells on the pulse intensity were obtained for the cells exposed to single square-wave electric pulses with the durations of 0.02-2 ms. Then, the average cell radii were measured for each cell line and the transmembrane potential induced by the external electric field was calculated. The obtained values of the transmembrane potential were in the range of 480-930 mV and decreased with increasing pulse duration. The obtained dependences of the transmembrane potential required to electroporate 50% of cells on the pulse duration were close to each other for all cell lines studied.
Źródło:
Acta Physica Polonica A; 2009, 115, 6; 1056-1058
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
High-Voltage Pulses Potentiate Bleomycin Cytotoxicity Towards Cancer Cells in vitro
Autorzy:
Saulė, R.
Saulis, G.
Batiuškaitė, D.
Powiązania:
https://bibliotekanauki.pl/articles/1807930.pdf
Data publikacji:
2009-06
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
87.50.cj
87.80.Fe
87.50.cf
Opis:
In this study the influence of high-voltage pulses on bleomycin cytotoxicity towards mouse hepatoma MH-22A and rat glioma C6 cells in vitro was determined. It was obtained that combining bleomycin with pulses of strong electric field significantly enhances the number of cells killed by bleomycin. Bleomycin alone was cytotoxic to both cell lines at concentrations above 1 μM. Treatment of cells by electric pulses in the presence of bleomycin greatly potentiated its cytotoxicity towards both cell lines tested - the bleomycin concentration required to reduce cell survival by 50% was 3.5-3.8 nM only. Exposure of cells to electric pulses only did not reduce cell viability.
Źródło:
Acta Physica Polonica A; 2009, 115, 6; 1098-1100
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Rabbit Retinal Ganglion Cell Activation Thresholds in Response to Various Electrical Stimulation Waveforms using a Different Spatial Resolution Electrode Array
Autorzy:
Çelik, M.
Özden, M.
Karagöz, İ.
Sobaci, G.
Powiązania:
https://bibliotekanauki.pl/articles/1032334.pdf
Data publikacji:
2017-06
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
87.85.-d
87.85.D-
87.85.E-
87.85.eg
87.55.dh
87.19.lb
87.85.Ng
Opis:
The analysis of retinal ganglion cell responses to electrical stimulation is invaluable way to understand how the retina reacts and develops. Artificial visual prosthetics have made progress to some extent. Although there are several studies about retinal ganglion cell responses in the literature, experimental findings and information about responses to special stimulation patterns for developing high-resolution visual prosthetics are quite limited. In this study, rabbit retinal tissue was stimulated by biphasic, monophasic and ramp function current pulses with various amplitudes and pulse widths in a set of in vitro experiments. Rabbit retinal ganglion cell responses and spike activities are comparatively analyzed based on the applied electrical stimulation parameters. We conclude that biphasic current pulses provide a lower stimulation threshold of 10 μA with shorter pulse widths than those obtained by monophasic stimulation. Additionally, despite the fact that ramp function stimulation patterns have remarkable potential for eliciting spike formation with low stimulation thresholds, biphasic stimulation is charge-balanced and more convenient for high-resolution visual prosthesis systems.
Źródło:
Acta Physica Polonica A; 2017, 131, 6; 1479-1484
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Path Planning for Multiple Mobile Robots Using A* Algorithm
Autorzy:
Batik Garip, Z.
Karayel, D.
Ozkan, S.
Atali, G.
Powiązania:
https://bibliotekanauki.pl/articles/1031599.pdf
Data publikacji:
2017-09
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
42.30.Tz
45.40.Ln
87.85.St
87.55.de
87.55.K-
87.55.kd
Opis:
One of the main problems in path planning for multiple mobile robots is to find the optimal path between two points so that robots can follow the shortest path and consume the least energy. Also, motion planning is important to avoid collisions if multiple mobile robots are running together within environments with obstacles. In this study, motion planning for multiple robots has been proposed. It is desired that robots could move in coordination with each other from the starting point to the destination point on a plane. The coordinates of the objects and mobile robots have been acquired using image processing with a single ceiling camera. The path planning for the shortest distance has been performed using A* algorithm in dynamic frame between robot-object and object-target point, respectively. A graphical user interface has been developed based on MATLAB GUI. It is hoped that the developed system will have a wide area of applications in industry and will make important contributions for the improvement of manufacturing, assembly, transportation and storage technologies.
Źródło:
Acta Physica Polonica A; 2017, 132, 3; 685-688
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The INSIDE Project: Innovative Solutions for In-Beam Dosimetry in Hadrontherapy
Autorzy:
Marafini, M.
Attili, A.
Battistoni, G.
Belcari, N.
Bisogni, M.
Camarlinghi, N.
Cappucci, F.
Cecchetti, M.
Cerello, P.
Ciciriello, F.
Cirrone, G.
Coli, S.
Corsi, F.
Cuttone, G.
De Lucia, E.
Ferretti, S.
Faccini, R.
Fiorina, E.
Frallicciardi, P.
Giraudo, G.
Kostara, E.
Kraan, A.
Licciulli, F.
Liu, B.
Marino, N.
Marzocca, C.
Matarrese, G.
Morone, C.
Morrocchi, M.
Muraro, S.
Patera, V.
Pennazio, F.
Peroni, C.
Piersanti, L.
Piliero, M.
Pirrone, G.
Rivetti, A.
Romano, F.
Rosso, V.
Sala, P.
Sarti, A.
Sciubba, A.
Sportelli, G.
Voena, C.
Wheadon, R.
Del Guerra, A.
Powiązania:
https://bibliotekanauki.pl/articles/1402609.pdf
Data publikacji:
2015-05
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
87.53.Bn
87.53.Jw
87.53.Kn
87.55.N-
87.55.ne
87.57.uq
Opis:
The INSIDE project addresses the online dose monitoring in particle therapy issue. The proposed detectors exploit the secondary neutral and charged particles emitted during the treatment by the irradiated volumes. The new detection techniques allow to return and online a measurement of the released dose and the Bragg peak position.
Źródło:
Acta Physica Polonica A; 2015, 127, 5; 1465-1467
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A Study of Monitoring Performances with the INSIDE System
Autorzy:
Pennazio, F.
Attili, A.
Battistoni, G.
Belcari, N.
Bisogni, M.
Camarlinghi, N.
Cappucci, F.
Cecchetti, M.
Cerello, P.
Ciciriello, F.
Cirrone, G.
Coli, S.
Corsi, F.
Cuttone, G.
De Lucia, E.
Ferretti, S.
Faccini, R.
Fiorina, E.
Frallicciardi, P.
Giraudo, G.
Kostara, E.
Kraan, A.
Licciulli, F.
Liu, B.
Marafini, M.
Marino, N.
Marzocca, C.
Matarrese, G.
Morone, C.
Morrocchi, M.
Muraro, S.
Patera, V.
Peroni, C.
Piersanti, L.
Piliero, M.
Pirrone, G.
Rivetti, A.
Romano, F.
Rosso, V.
Sala, P.
Sarti, A.
Sciubba, A.
Sportelli, G.
Voena, C.
Wheadon, R.
Del Guerra, A.
Powiązania:
https://bibliotekanauki.pl/articles/1402611.pdf
Data publikacji:
2015-05
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
87.53.Bn
87.53.Jw
87.53.Kn
87.55.N-
87.55.ne
87.57.uq
Opis:
The INSIDE collaboration aims to build an on-line hadrontherapy monitoring system, based on a dual-head in-beam PET scanner and a secondary charged particles profiler. In this work preliminary experimental results are presented. The validation of the FLUKA-based Monte Carlo simulation tool is shown together with the expected scanner performances.
Źródło:
Acta Physica Polonica A; 2015, 127, 5; 1468-1470
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Status and Vision for Structural Biology at the Canadian Light Source
Autorzy:
Grochulski, P.
Fodje, M.
George, G.
Powiązania:
https://bibliotekanauki.pl/articles/1431525.pdf
Data publikacji:
2012-04
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
87.64.kd
87.80.Dj
Opis:
The status and vision for Structural Biology at the Canadian Light Source (CLS) is presented. The beamlines that have been described in the paper represent a Canadian national resource that is available to science and industry world-wide. They include state-of-the-art infrastructure and include specialized capabilities, many of which are not available elsewhere, including macromolecular crystallography, biological X-ray spectroscopy, soft X-ray spectromicroscopy, as well as small angle and wide angle X-ray scattering beamlines. The vision for Structural Biology at the Canadian Light Source is significantly enhanced by the synergies and collaborations between the users of the different beamlines and by the strengths of the scientific personnel and trainees.
Źródło:
Acta Physica Polonica A; 2012, 121, 4; 866-870
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
PAAm-Kappa Carrageenan Composites: Drying and Swelling with Various Kappa Carrageenan Contents
Autorzy:
Akin Evıngür, G.
Pekcan, Ö.
Powiązania:
https://bibliotekanauki.pl/articles/1490972.pdf
Data publikacji:
2012-01
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
82.35.Lr
83.80.Kn
87.15.Vv
87.15.Zg
87.64.kv
Opis:
The purpose of this study is to discuss the role of kappa-carrageenan (κ-car) in the drying and swelling of polyacrylamide (PAAm)-κ-car composite. The fluorescence intensity of pyranine increased and decreased as drying and swelling time were increased respectively for all samples. The desorption coefficient, $D_{d}$, decreased as κ-car contents were increased for a given temperature during drying. However, cooperative diffusion coefficient, $D_{s}$, increased as κ-car contents were increased during swelling at a given temperature.
Źródło:
Acta Physica Polonica A; 2012, 121, 1; 169-171
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Elemental Mapping of Prostate Tissue by Micro-SRIXE
Autorzy:
Banaś, A.
Banaś, K.
Falkenberg, G.
Dyduch, G.
Kwiatek, W. M.
Powiązania:
https://bibliotekanauki.pl/articles/2044669.pdf
Data publikacji:
2006-03
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
87.64.-t
Opis:
Synchrotron radiation-induced X-ray emission is now a proven analytical method for the determination of trace elements. Better insight of the role of trace elements in tissue samples can be gained by acquiring complete distribution maps of these elements. Our approach is based on the acquisition of digital maps. In this contribution we present two different methods for obtaining normalization matrix: first - based on argon intensity in the single spectrum and second - based on changes of beam current intensity. The region for the scan was carefully chosen according to the histological view of the sample. A total area was scanned with a step size of 15 μm in each direction and measuring time of 30 s per pixel. The thickness of the samples was 15 μm. A polycapillary was used for beam focusing. At the energy of 18 keV the beam size on the sample was approximately 15 μm which is of the order of a cell diameter.
Źródło:
Acta Physica Polonica A; 2006, 109, 3; 323-328
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Structural Complexity and Fluorescence Heterogeneous Decays in Proteins
Autorzy:
Di Venere, A.
Mei, G.
Rosato, N.
Finazzi Agro, A.
Gilardi, G.
Powiązania:
https://bibliotekanauki.pl/articles/1963361.pdf
Data publikacji:
1997-04
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
87.15.Mi
Opis:
Optical spectroscopy is a suitable technique to study the functional and structural properties of large biomolecules in solution without damaging the samples. In particular, measurements of time-resolved fluorescence may give important information on the tertiary structure of proteins. Furthermore, the study of fluorescence depolarization as a function of time is a very common method to follow the dynamics of the local domains and subunits which form the quaternary structure of oligomeric enzyme. The analysis of fluorescence decays in terms of continuous distribution of lifetimes seems to be an appropriate approach to describe the dynamics of proteins which ranges over an enormous time scale (from 10 ps to 10 ns). The results obtained for several proteins are reported and discussed. The data provide further confirmation of the correlation which exist between heterogeneous fluorescence decays and a hierarchy of many conformational substates in proteins.
Źródło:
Acta Physica Polonica A; 1997, 91, 4; 731-737
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Alginate Biopolymer Coatings Obtained by Electrophoretic Deposition on Ti15Mo Alloy
Autorzy:
Szklarska, M.
Dercz, G.
Simka, W.
Dudek, K.
Starczewska, O.
Łężniak, M.
Łosiewicz, B.
Powiązania:
https://bibliotekanauki.pl/articles/1360727.pdf
Data publikacji:
2014-04
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
87.18.Fx
87.85.J-
82.35.Pq
87.15.rp
81.15.-z
Opis:
In this work, the electrophoretic deposition method has been developed for the fabrication of bioactive alginate coatings on the surface of Ti15Mo implant alloy. Thin ZnO film was deposited cataphoretically as the interlayer prior to anaphoretic deposition of alginate (Alg) which was performed from aqueous solution containing 1 g $dm^{- 3}$ of NaAlg at room temperature. The deposition voltage and time varied in the range 20-50 V and 30-120 min, respectively. The microstructure of Alg coatings was studied by scanning electron microscope, and the surface roughness was analysed using atomic force microscopy. Structure was studied by grazing incidence X-ray diffraction. Chemical composition and functional group were examined using energy dispersive spectrometry and attenuated total reflectance Fourier transform infrared spectroscopy methods, respectively. It was found that controlling the deposition conditions it is possible to obtain amorphous Alg coatings of variable thickness and porosity. Mechanism of electrophoretic deposition of bioactive Alg coatings on the Ti15Mo alloy surface was discussed.
Źródło:
Acta Physica Polonica A; 2014, 125, 4; 919-923
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Methodology for FTIR Imaging of Individual Cells
Autorzy:
Yao, Seydou
Cestelli Guidi, M.
Delugin, M.
Della-Ventura, G.
Marcelli, A.
Petibois, C.
Powiązania:
https://bibliotekanauki.pl/articles/1398831.pdf
Data publikacji:
2016-02
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
82.80.-d
87.85.Pq
87.64.-t
Opis:
FTIR imaging is a novel spectroscopic technique able to provide cell imaging, in vivo and in real-time. However, one key issue is developing methodologies for cell culture on IR-transparent substrates fitting cell biology requirements. In this work we tested different IR-transparent substrates in terms of biotoxicity, surface properties, and spectral image acquisition qualities. Only a few substrates, namely Si₃N₄, Ge, GLS, LaF₃, Si, SrF₂, ZnS/C, ZnS/F, were found to provide cell culture conditions comparable to those observed on usual polycarbonate Petri dishes, the main limiting parameter being the toxicity of the material (ZnS, GLS, PbF₂, PbCl₂) or a poor adhesiveness (notably diamond, AgCl, CaF₂, ZnS). From substrates eligible for a good-quality cell culture, the spectral acquisition quality is mainly affected by the refractive index value. Finally, the best compromise between cell culture quality and image spectral quality could be obtained using Si and Ge substrates. This rationalization of the available IR-transparent substrates for bioimaging is particularly relevant for live cell analyses, where cell culture conditions must remain unaffected by substrate properties.
Źródło:
Acta Physica Polonica A; 2016, 129, 2; 250-254
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Distinguishing Prostate Cancer from Hyperplasia
Autorzy:
Kwiatek, W. M.
Banaś, A.
Banaś, K.
Podgórczyk, M.
Dyduch, G.
Falkenberg, G.
Gajda, M.
Cichocki, T.
Powiązania:
https://bibliotekanauki.pl/articles/2044731.pdf
Data publikacji:
2006-03
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
87.64.-t
Opis:
The prostate gland is the most common site of neoplastic disorders in men. The knowledge of the pathogenesis of benign prostate hyperplasia and prostate cancer is still under investigation. X-ray fluorescence analysis using synchrotron radiation seems to be an appropriate technique to study the elemental composition of biological tissues. The measurements presented in this paper were carried out on the L-beam line at the HASYLAB, DESY (Germany). The observed concentrations of Fe, Cu, Mn, and Zn are significantly higher in cancerous tissues, as compared to normal and hyperplastic ones. Our results reveal also the existence of the two types of hyperplasia.
Źródło:
Acta Physica Polonica A; 2006, 109, 3; 377-381
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Assessment of patient dose by positron emission tomography (PET) and medical internal dose (MIRD) methods
Autorzy:
Yilmaz, G.
Tugrul, A.
Demir, M.
Yasar, D.
Demir, B.
Powiązania:
https://bibliotekanauki.pl/articles/1068158.pdf
Data publikacji:
2016-07
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
87.57.uk
87.53.Bn
Opis:
Dynamic experiments cannot be observed easy on patients for determination of dosimetry in human PET studies dosimeter studies. In this study, it is aimed to estimate dose amount absorbed by some critical organs (e.g. bladder, lung, thyroid and ovary) by using a developed phantom. The phantom was improved as an original anthropomorphic whole body phantom which has been arranged with dynamic system. Therefore, organ absorbed doses by applying of fluorine-18-fluorodeoxyglucose in PET studies and was observed by using the phantom, while TLD dosimeters were used for determination of internal absorbed doses. In medical physics, the accuracy of absorbed dose resulting from radiopharmaceutical application was determined by the medical internal radiation dose method that depends theoretically on the cumulated activity of the source organs and their mass. The MIRD calculation was also used for the study and comparatively evaluated with the experimental results which were collected by using improved phantom.
Źródło:
Acta Physica Polonica A; 2016, 130, 1; 90-92
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Preliminary Study on Chemical Speciation of Sulphur in Cancerous Tissues
Autorzy:
Kwiatek, W. M.
Banaś, A.
Banaś, K.
Kisiel, A.
Cinque, G.
Falkenberg, G.
Powiązania:
https://bibliotekanauki.pl/articles/2044744.pdf
Data publikacji:
2006-03
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
87.64.Gb
Opis:
Sulphur is vital for almost all living organisms by participating in a wide variety of metabolic processes. Nevertheless its biochemistry is only partially understood, due to it a few tools such as X-ray absorption near edge structure may be used to determine its chemical speciation in biological system. In this paper we focused on analysis of composition and elemental distribution in tissue structures of biological samples. We examined cancerous and non-cancerous prostate tissues. Experiments were carried out on the L-beam line at the HASYLAB, DESY (Hamburg, Germany) and DAΦNE-Light Facility at the Laboratori Nationali di Frascati (Frascati, Italy). Synchrotron radiation induced X-ray emission measurements reveal the significant differences in concentration of sulphur between cancerous and non-cancerous tissues. X-ray absorption near edge structure spectra show two main types of sulphur that are represented by X-ray peaks at 2476 eV and 2484 eV. This suggests that different sulphur components are present in the measured samples.
Źródło:
Acta Physica Polonica A; 2006, 109, 3; 383-387
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Spin-Dependent Effects in Helical Molecular Systems with Rashba-Like Spin-Orbit Interaction
Autorzy:
Gutierrez, R.
Cuniberti, G.
Powiązania:
https://bibliotekanauki.pl/articles/1384094.pdf
Data publikacji:
2015-02
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
73.22.-f
73.63.-b
72.25.-b
87.14.gk
87.15.Pc
Opis:
Strong spin-selective effects have been recently observed in both photoemission and electrical transport experiments in biomolecular systems, opening fascinating possibilities for interfacing semiconductor and biomolecular systems to create highly efficient spintronics devices. From the theoretical and experimental point of view there are strong suggestions that molecular chirality is playing a crucial role. In this study we extend a previously formulated model (R. Gutierrez, E. Díaz, R. Naaman, G. Cuniberti, Phys. Rev. B 85, 081404 (2012)) describing the linear propagation of a charge with spin along the axis of a helical charge distribution. We explore different parameter regions and show that a strong negative spin polarization as observed in the previously mentioned experiments can be obtained with reasonable values of both the electronic coupling elements and the helical field induced spin-orbit interaction.
Źródło:
Acta Physica Polonica A; 2015, 127, 2; 185-191
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Applications of Free Electron Lasers in Biology and Medicine
Autorzy:
Pełka, J.
Tybor, K.
Nietubyć, R.
Wrochna, G.
Powiązania:
https://bibliotekanauki.pl/articles/1539156.pdf
Data publikacji:
2010-02
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
87.59.-e
41.60.Cr
07.85.Qe
82.53.Ps
87.64.Bx
Opis:
The advent of free electron lasers opens up new opportunities to probe the dynamics of ultrafast processes and the structure of matter with unprecedented spatial and temporal resolution. New methods inaccessible with other known types of radiation sources can be developed, resulting in a breakthrough in deep understanding the fundamentals of life as well as in numerous medical and biological applications. In the present work the properties of free electron laser radiation that make the sources excellent for probing biological matter at an arbitrary wavelength, in a wide range of intensities and pulse durations are briefly discussed. A number of biophysical and biomedical applications of the new sources, currently considered among the most promising in the field, are presented.
Źródło:
Acta Physica Polonica A; 2010, 117, 2; 427-432
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Identification of Gastric Cancer from Speckle Patterns
Autorzy:
Andrade-Eraso, C.
Patiño-Velasco, M.
Vásquez-López, J.
León, J.
Bolaños-Pantoja, G.
Trivi, M.
Powiązania:
https://bibliotekanauki.pl/articles/1490749.pdf
Data publikacji:
2012-01
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
78.68.+m
42.87.-d
87.50.W-
Opis:
Speckle technique is based on the light intensity distribution randomly formed when a laser light is reflected on a rough surface, creating a pattern of illuminated grains (constructively) and dark (destructive) on scales of 1 μm. When the samples are displaced or deformed, the speckle pattern is altered. In this paper we present speckle patterns obtained from samples of gastric mucosa that is physically altered for the carcinogenesis process. Biopsies were studied with different diagnoses and were grouped according to the characteristics of speckle patterns. Speckle patterns were obtained by illuminating the samples with green laser. Morphological parameters of the speckle patterns reveal existence of 3 descriptors: the average grain size, hydraulic radius and the radio of the Weddel disc, which showed a high, intermediate and low value. The comparison shows agreement between the histopathological diagnosis and the values obtained by the speckle technique, making this technique emerge as a new classification system for quantitative diagnosis of precancerous lesions.
Źródło:
Acta Physica Polonica A; 2012, 121, 1; 62-64
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Ellipsometrical and SEM Study of Ferritin Adsorption οn a Gold Surface
Autorzy:
Vladimirova, L.
Tsutsumanova, G.
Gritzkow, Al.
Savov, V.
Powiązania:
https://bibliotekanauki.pl/articles/1795711.pdf
Data publikacji:
2009-10
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
79.60.Dp
87.64.Ee
87.14.Df
82.45.Jm
Opis:
The adsorption of horse spleen ferritin on gold surface is studied with null ellipsometry and scanning electron microscopy. The high sensitivity and in situ advantage of ellipsometry make it very attractive for studies of ultrathin biomolecular layers. The influence of pH and protein concentration in solution on the adsorption kinetics was interpreted using ex situ scanning electron microscopy shots and computer modeling of the system "prism-gold film-adsorbed layer-solution". It seems that the first fast stage comprises nucleation process occurring at active sites and the following slow multistage process of a protein film growth. The data about adsorption kinetics of protein and the structure of the adsorbate layers obtained in this study enable understanding of such processes in real biological system, e.g. the protein adsorption on blood vessels and tissues in pathological processes.
Źródło:
Acta Physica Polonica A; 2009, 116, 4; 705-707
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The Light Harvesting Process in Purple Bacteria
Autorzy:
Krueger, B. P.
Scholes, G. D.
Yu, J.- Y.
Fleming, G. R.
Powiązania:
https://bibliotekanauki.pl/articles/1993667.pdf
Data publikacji:
1999-01
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
87.15.Mi
82.20.Rp
42.50.Md
Opis:
We present and review the results of fluorescence upconversion and photon echo experiments, and $ab initio$ calculations performed in our group within the last few years with respect to the light harvesting process in purple bacteria. Carotenoids transfer energy to bacteriochlorophyll (BChl) mainly via the carotenoid S$\text{}_{2}$ → BChl Q$\text{}_{x}$ pathway on a ~100 fs timescale. This transfer is reasonably reproduced by considering the Coulombic coupling calculated using the transition density cube method which is valid at all molecular separations. Carotenoids may also serve a role in mediating B800 → B850 energy transfer in LH2 by perturbing the transition density of the B850 as shown by ab initio calculations on a supermolecule of two B850 BChls, one carotenoid and one B800 BChl. Further calculations on dimers of B850 BChl estimate the intra- and interpolypeptide coupling to be 315 and 245 cm$\text{}^{-1}$, respectively. These interactions are dominated by Coulombic coupling, while the orbital overlap dependent coupling is ~20% of the total. Photon echo peak shift experiments (3PEPS) on LH1 and the B820 subunit are quantitatively simulated with identical parameters aside from an energy transfer time of 90 fs in LH1 and ∞ in B820, suggesting that excitation is delocalized over roughly two pigments in LH1. 3PEPS data taken at room and low temperature (34 K) on the B800-B820 suggest that static disorder is the dominant mechanism localizing excitation in LH1 and LH2. We suggest that the competition between the delocalizing effects of strong electronic coupling and the localizing effects of disorder and nuclear motion results in excitation in the B850 and B875 rings being localized on 2-4 pigments within approximately 60 fs.
Źródło:
Acta Physica Polonica A; 1999, 95, 1; 63-83
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Time-Resolved X-Ray Diffraction Studies on Biological Systems
Autorzy:
Rapp, G.
Powiązania:
https://bibliotekanauki.pl/articles/1920834.pdf
Data publikacji:
1992-07
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
61.10.-i
87.80.+s
52.50.Jm
Opis:
Understanding of biological function requires knowledge both on structural and dynamical aspects. The aim of time-resolved X-ray diffraction is to combine structural and kinetic methods by monitoring structural or conformational changes within a single protein or assemblies of proteins during their biological action in real time. This requires (i) a powerful X-ray source, (ii) appropriate detectors capable of dealing with high local and total count rates and (iii) a suitable trigger mechanism. These aspects are briefly discussed with emphasis on light as trigger for initiation of structural or conformational changes. Examples are presented on muscle contraction, lipid phase transitions, the photocycle of bacteriorhodopsin and the application of Laue crystallography on the protein p21.
Źródło:
Acta Physica Polonica A; 1992, 82, 1; 103-120
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Small Angle X-Rays Scattering Studies of Biomolecules
Autorzy:
Funari, S. S.
Powiązania:
https://bibliotekanauki.pl/articles/2030570.pdf
Data publikacji:
2002-05
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
61.10.-i
87.80.-y
64.75.+g
Opis:
The building units of biological systems, the biomolecules, cannot easily be organized or even classified into defined categories. They can be as simple as water or complex as tintin, a muscle protein extremely large with several thousand atoms. To understand their function, one must know their characteristics, where they occur and what they do. One approach to reach such an ambitious task is to determine their structure, as single molecules or assembled into aggregates. Small angle X-ray scattering is the most important method for this purpose. We present studies carried out on several systems, and aiming at different questions about them. We start with lipids, the main components of the cell membranes. These membranes form the cell boundaries, the moiety required for the so-called membrane proteins, but also influence significantly several aspects of biological activity. More complex systems like a muscle fibre is also presented, showing that changes in the structure are related to the movement mechanism. It becomes easy to conclude that knowing the structures and the changes occurring in them is an important way to understand the function of biomolecules and therefore their role in the life cycle.
Źródło:
Acta Physica Polonica A; 2002, 101, 5; 647-658
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Light Scattering Studies of Hydration and Structural Transformations of Lysozyme
Autorzy:
Szymańska, A.
Ślósarek, G.
Powiązania:
https://bibliotekanauki.pl/articles/1489917.pdf
Data publikacji:
2012-03
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
87.15.kr
34.50.-s
Opis:
We have applied the method of dynamic light scattering to analyse the lysozyme-ethanol interaction. For low ethanol concentration (below 4.3% (v/v)) no chemical denaturation process is observed. When the ethanol concentration grows above the triggering concentration the hydrodynamic radius of lysozyme increases, indicating the structural changes within the protein molecule. The observed structural modifications are attributed to dehydration and preliminary tertiary structure modification of the protein molecule.
Źródło:
Acta Physica Polonica A; 2012, 121, 3; 694-698
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Evaluation of Surface Characteristics and Physical Properties on Biodegradable Magnesium-Calcium Alloys by Anodic Oxidation
Autorzy:
Kim, J.
Lee, J.
Yang, H.
Park, S.
Lim, H.
Oh, G.
Yun, K.
Powiązania:
https://bibliotekanauki.pl/articles/1191716.pdf
Data publikacji:
2016-04
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
87.85.jj
87.85.jc
Opis:
The purpose of this study was to determine the effect of calcium (Ca) on the surface characteristics and physical properties of magnesium-calcium alloys after anodization. A novel binary alloy Mg-xCa (in which x=0.5, 1, or 5 wt.%) was cast by combining magnesium (99.9%) and calcium (99.9%) in an argon gas (99.99%) atmosphere. A magnesium alloy rod having a diameter of 15 mm was cut into discs, each 2 mm thick. The specimens were subjected to anodic oxidation at 120 V for 15 minutes at room temperature in an electrolyte solution consisting of calcium gluconate, sodium hexametaphosphate, and sodium hydroxide. Surface and cross-sectional morphological changes were observed using scanning electron microscopy, and the microstructures and phases were detected by means of X-ray diffraction. Hardness and surface roughness were assessed by means of a Vickers hardness tester and a surface roughness meter, respectively. The results show that the physical properties of these magnesium-calcium alloys have been improved, because it was possible to control the dissolution rate according to the amount of calcium added.
Źródło:
Acta Physica Polonica A; 2016, 129, 4; 736-741
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:
X-Ray Absorption Near Edge Spectroscopy of Sulfur in Biomolecules: Two Examples from Glutathione and Insulin
Autorzy:
Cinque, G.
Bellisola, G.
Colombatti, M.
Burattini, E.
Powiązania:
https://bibliotekanauki.pl/articles/2044672.pdf
Data publikacji:
2006-03
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
78.70.Dm
87.64.Gb
Opis:
Although a minor constituent of cell and tissues, sulfur is an essential element to fulfil a wide range of biological processes, and it is present in the functional groups of many biomolecules that participate to redox reactions in vivo. Cysteine, one of the two S-containing aminoacids present in proteins, contains sulfur in fully reduced form and its thiol group can undergo a range of reactions under physiological conditions. X-ray absorption spectroscopy represents a unique tool to speciate the redox state of sulfur in biomolecules because of the known strong correlation between oxidation state and absorption edge energy shift (over 10 eV). Moreover, a rich X-ray absorption near edge structure is related to the chemical structures of S-containing biomolecules, as well as significant spectral changes due to biochemical action. The formation of a disulfide bond, i.e. a covalent linkage between the S atoms of two cysteine residues, or its reduction were investigated only indirectly in biomolecules. X-ray absorption spectroscopy experiments at the sulfur K-edge were performed at the soft X-ray beamline in Frascati using the wiggler source of the 0.51 GeV storage ring DAΦNE. X-ray absorption near edge structure data were collected to distinguish in situ between S-thiol and disulfide on model protein systems. Such preliminary results confirm this technique as a unique probe of sulfur chemistry in vivo. Quantitative speciation of S-metabolites can be foreseen in biological tissues with no chemical manipulations of the specimen.
Źródło:
Acta Physica Polonica A; 2006, 109, 3; 335-340
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Irradiation of Living Cells with Single Ions at the Ion Microprobe SNAKE
Autorzy:
Hauptner, A.
Cremer, T.
Deutsch, M.
Dietzel, S.
Drexler, G. A.
Greubel, C.
Hable, V.
Krücken, R.
Löwe, R.
Strickfaden, H.
Dollinger, G.
Friedl, A. A.
Powiązania:
https://bibliotekanauki.pl/articles/2044655.pdf
Data publikacji:
2006-03
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
29.27.Eg
61.80.Jh
87.16.Sr
87.50.Gi
Opis:
The irradiation setup at the ion microprobe SNAKE is used to irradiate living cells with single energetic ions. The irradiation accuracy of 0.55μm and respectively 0.40μm allows to irradiate substructures of the cell nucleus. By the choice of ion atomic number and energy the irradiation can be performed with a damage density adjustable over more than three orders of magnitude. Immunofluorescence detection techniques show the distribution of proteins involved in the repair of DNA double-strand breaks. In one of the first experiments the kinetics of appearance of irradiation-induced foci in living HeLa cells was examined. In other experiments a new effect was detected which concerned the interaction between irradiation events performed at different time points within the same cell nucleus.
Źródło:
Acta Physica Polonica A; 2006, 109, 3; 273-278
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Electrochemical Formation of Self-Organized Nanotubular Oxide Layers on Ti13Zr13Nb Alloy for Biomedical Applications
Autorzy:
Smołka, A.
Rodak, K.
Dercz, G.
Dudek, K.
Łosiewicz, B.
Powiązania:
https://bibliotekanauki.pl/articles/1361071.pdf
Data publikacji:
2014-04
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
87.85.jj
81.07.De
87.85.J-
Opis:
In this work, the anodic formation of self-organized nanotubular oxide layers on Ti13Zr13Nb implant alloy was presented. Anodic oxidation was carried out at room temperature in [1 M] $(NH_4)_2SO_4$ solution with 1 wt% content of $NH_4F$. The voltage and time of anodization was 20 V for 120 min, respectively. Under proposed conditions, the best arrangement of nanopores was observed. The physical and chemical properties of the anodized surface of the Ti13Zr13Nb alloy were characterized using grazing incidence X-ray diffraction, scanning transmission electron microscopy, and atomic force microscopy. It was found that diameter of nanopores varied from 10 to 32 nm. Mechanism of the fabrication of the unique 3D tube-shaped nanostructure of $TiO_2$ on the surface of the Ti13Zr13Nb alloy by electrochemical anodization, has been discussed.
Źródło:
Acta Physica Polonica A; 2014, 125, 4; 932-935
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
In the Search of Electron Correlation Effects in DNA
Autorzy:
Wróbel, A.
Wróbel, P.
Powiązania:
https://bibliotekanauki.pl/articles/1537235.pdf
Data publikacji:
2010-08
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
87.14.gk
75.20.-g
71.10.Fd
Opis:
We discuss the energy scale separation induced in DNA by gaps between molecular orbital states of individual bases and by electron correlations. We also demonstrate how this separation gives rise to effective low energy models of electron transport in DNA.
Źródło:
Acta Physica Polonica A; 2010, 118, 2; 409-412
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Quietness in the Soundscape of the Białowieża National Park
Autorzy:
Wiciak, J.
Mleczko, D.
Ozga, A.
Wszołek, G.
Wierzbicki, J.
Piechowicz, J.
Małecki, P.
Powiązania:
https://bibliotekanauki.pl/articles/1402187.pdf
Data publikacji:
2015-07
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
43.66.-x
43.66.+y
87.18.Tt
87.19.lc
43.50.Rq
Opis:
The quietness, defined as the near or complete absence of sound, in the context of the natural environment protection, may be considered a state in which no undesired of foreign sounds occur, and, by analogy to noise, analyzed in two aspects: that pertaining to measurements and the subjective one. The article discusses the lowest levels of sounds recorded at night in the soundscape of the Białowieża Forest. Due to low levels of the examined sounds and the technical problems that occurred while the sounds were being measured and registered, the acoustic examination of the measurement set-up in an anechoic chamber has also been presented. The research is aimed at defining precisely the concept of quietness prevailing in the nature in the subjective aspect by determining both the range of levels and the characteristics of preferred sounds.
Źródło:
Acta Physica Polonica A; 2015, 128, 1A; A-79-A-84
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Upgrade of the Electroporation Device KEA-MOBIL
Autorzy:
Sack, M.
Attmann, F.
Stängle, R.
Wolf, A.
Frey, W.
Müller, G.
Powiązania:
https://bibliotekanauki.pl/articles/1807923.pdf
Data publikacji:
2009-06
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
87.50.cj
Opis:
For the production of synthetic bio-fuel the use of green biomass enables additional resources of raw material supplementary to the commonly used dry material. An electroporation assisted drying process gives the opportunity of a more efficient dewatering than only pressing and subsequent drying. Experiments showed a lower relative humidity of the pressed material after electroporation compared to pressing the raw material only. Moreover, the drying process of the electroporated material was much shorter. This is because the pores formed in the cell membranes foster a better extraction of water during pressing and enhance the diffusion process during the drying process. The paper presents exemplarily the experimental results for green rye. For the electroporation-assisted drying process the electric contact to the plant material has to be established by means of the juice inside the plants only rather than adding additional water. Hence, for experiments in larger scale, the existing electroporation device KEA-MOBIL has been equipped with a new combined electroporation reactor and press. The reactor has a plate electrode system, whose upper electrode additionally serves as a piston to apply mechanical force to extract juice for a good electrical contact between plant material and the electrodes. A two-stage Marx generator serves as a pulse source. To reduce the insulation distance to the walls of the shielding cabin the Marx generator is operated in ground symmetric configuration. The device has been designed for a batch-wise throughput of 50 kg/h. An automatic feeding device enables the alternating use of two test vessels. The device has been tested on-site on a farm with green rye and grass.
Źródło:
Acta Physica Polonica A; 2009, 115, 6; 1081-1083
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Primary Electron Transfer Reactions in Membrane-Bound Open and Closed Reaction Centers from Purple Bacterium Rhodobacter sphaeroides
Autorzy:
Gibasiewicz, K.
Pajzderska, M.
Karolczak, J.
Burdziński, G.
Dobek, A.
Jones, M.
Powiązania:
https://bibliotekanauki.pl/articles/1419491.pdf
Data publikacji:
2012-08
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
82.50.-m
87.64.K-
87.15.M-
Opis:
Most ultrafast transient absorption studies of primary electron transfer in reaction centers from purple bacteria have been performed in complexes isolated from their natural lipid membrane environment using detergent. In this contribution we present near-UV-vis transient absorption studies of reaction centers embedded in their natural membrane environment. The evolution of absorption spectra recorded with subpicosecond resolution and reflecting primarily electron transfer reactions has been compared to data obtained previously for isolated reaction centers. We conclude that the overall spectral evolution in both types of samples is similar, and the environment of the reaction center protein has only a minor effect on the primary electron transfer reactions. The differences between the two samples are explained in terms of different energetic levels (and their different temporal evolution) of the two initial charge separated states $P^+B_A^-$ and $P^+H_A^-$, with P being the primary electron donor and $B_A$ and $H_A$ the two consecutive electron acceptors. Additionally, in the electric field generated by $P^+H_A^-,$ $B_A$ in membrane-bound reaction centers undergoes a stronger electrochromic shift than in isolated reaction centers.
Źródło:
Acta Physica Polonica A; 2012, 122, 2; 263-268
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The SAXS and Rheological Studies of HEWL Amyloid Formation
Autorzy:
Szymańska, A.
Ślósarek, G.
Hornowski, T.
Kozak, M.
Powiązania:
https://bibliotekanauki.pl/articles/1812257.pdf
Data publikacji:
2008-08
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
61.05.cf
87.14.E-
Opis:
We performed small angle X-ray scattering and rheological experiments in order to analyze the aggregation and denaturation processes of hen egg white lysozyme initiated by the presence of ethanol molecule. At low ethanol concentrations (below 60% (v/v)) we did not observe any change of the radius of gyration of lysozyme and no drastic changes in viscosity of the protein solution. With the increase in ethanol concentration up to the final concentration of 85% (v/v) the viscosity of protein solution dramatically increased. For high ethanol concentration a pseudoplastic behavior of lysozyme solution was observed, indicating a process of aggregation and reorientation of the protein molecules. Similar effects were observed in small angle X-ray scattering experiments. We assume that the analysis of the aggregation processes of the hen egg white lysozyme could contribute to our understanding of the mechanism of lysozyme amyloid formation.
Źródło:
Acta Physica Polonica A; 2008, 114, 2; 447-454
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Realization of a Phase Noise Measurement Bench Using Cross Correlation and Double Optical Delay Line
Autorzy:
Salzenstein, P.
Cussey, J.
Jouvenceau, X.
Tavernier, H.
Larger, L.
Rubiola, E.
Sauvage, G.
Powiązania:
https://bibliotekanauki.pl/articles/2047892.pdf
Data publikacji:
2007-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
06.30.Ft
43.50.Yw
87.64.M-
87.57.cm
Opis:
In this paper there are presented first results obtained with a phase noise measurement bench operating in X-band, realized in our laboratory, using double optical delay line and cross correlation. Phase noise floor using a microwave sapphire oscillator is better than -160 dB rad$\text{}^{2}$/Hz at 10 kHz from the 10 GHz carrier, using a 2 km optical delay line.
Źródło:
Acta Physica Polonica A; 2007, 112, 5; 1107-1111
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Structure and Dynamics of Colloidal Suspensions Studied by Means of XPCS
Autorzy:
Patkowski, A.
Gapinski, J.
Fluerasu, A.
Holmqvist, P.
Meier, G.
Lettinga, M.
Nägele, G.
Powiązania:
https://bibliotekanauki.pl/articles/1812242.pdf
Data publikacji:
2008-08
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
87.15.Vv
83.10.Mj
82.70.Dd
Opis:
Structure and dynamics of suspensions of charged colloidal spheres in water were studied by means of small-angle X-ray scattering and X-ray photon correlation spectroscopy using synchrotron radiation. Experimentally obtained dependences on the scattering vector q of the structure factor S(q), short-time collective diffusion coefficient D(q) and hydrodynamic function H(q) were in good agreement with theoretical predictions. No effect of screening of the hydrodynamic interactions, suggested in the literature, was found. The conditions are discussed at which the maximum of the hydrodynamic function peak value H(q_m) can be obtained experimentally.
Źródło:
Acta Physica Polonica A; 2008, 114, 2; 339-350
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Fermi-Surface Mapping from 2D Positron Annihilation Data
Autorzy:
Kontrym-Sznajd, G.
Samsel-Czekała, M.
Powiązania:
https://bibliotekanauki.pl/articles/2042174.pdf
Data publikacji:
2005-04
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
71.18.+y
13.60.Fz
87.59.Fm
Opis:
We demonstrate which kind of information on the electronic structure one can get from one-dimensional profiles, interpreted in terms of two-dimensional reconstructed densities. The conversion from one-dimensional to two-dimensional is applied to one-dimensional angular correlation of annihilation radiation profiles of divalent hexagonal close packed metals Mg and Cd. On the example of Mg we show that one should be very careful while studying the Fermi surface from electron-positron (e-p) densities folded into the first Brillouin zone.
Źródło:
Acta Physica Polonica A; 2005, 107, 4; 586-591
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Wyświetlanie 1-50 z 93

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