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Wyszukujesz frazę "87.85.E-" wg kryterium: Wszystkie pola


Wyświetlanie 1-30 z 30
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:
Composites for Bone Surgery Based on Micro- and Nanocarbons
Autorzy:
Stodolak, E.
Fraczek-Szczypta, A.
Blazewicz, M.
Blazewicz, S.
Powiązania:
https://bibliotekanauki.pl/articles/1535897.pdf
Data publikacji:
2010-09
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
81.05.Qk
81.05.uj
87.85.jj
87.85.jc
87.17.Ee
Opis:
In this work capabilities of polymer composites modified with carbon materials for application in the bone surgery were compared. The composite materials were produced from synthetic polymer PTFE-PVDF-PP modified with a carbon phase such as: short carbon fibres, carbon nanotubes and carbon fabrics. Determination of mechanical properties of the composite materials indicated that the carbon phase improves strength and Young's modulus of the composite. Moreover, the mechanical parameters can be controlled by the form and amount of the carbon phase introduced into the polymer matrix. Both the fibres and the carbon nanotubes influenced wettability and surface energy of the composites. Also topography of the materials surface was altered, and its roughness was optimal for bone cells (profilometry). Osteoblasts contacted with the polymer-carbon composites showed increased viability comparing with the ones contacting with the pure polymer foil (viability, and cells proliferation: MTT method, concentration of bone protein: viniculine and β-actine). Results of the investigations indicated that the composite materials containing carbon phases are potential materials for repairing of bone tissue damages.
Źródło:
Acta Physica Polonica A; 2010, 118, 3; 450-456
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Synchrotron Radiation in Biology and Medicine
Autorzy:
Pełka, J.
Powiązania:
https://bibliotekanauki.pl/articles/1812240.pdf
Data publikacji:
2008-08
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
87.57.-s
87.59.-e
07.85.Fv
07.90.+c
Opis:
This work is focused on a present status of synchrotron radiation X-ray applications in medicine and biology to imaging, diagnostics, and radiotherapy. Properties of X-ray beams generated by synchrotron sources are compared with radiation produced by classical laboratory X-ray tubes. A list of operating and planned synchrotron facilities applicable to biomedical purposes is given, together with their basic characteristics. A concise overview of typical X-ray synchrotron techniques in biology and medicine is carried out with discussion of their specific properties and examples of typical results.
Źródło:
Acta Physica Polonica A; 2008, 114, 2; 309-329
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
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:
Surface Study of Selected Biomaterials Using Vibrational Spectroscopy
Autorzy:
Paluszkiewicz, C.
Kwiatek, W.
Długoń, E.
Wesełucha-Birczyńska, A.
Piccinini, M.
Powiązania:
https://bibliotekanauki.pl/articles/1809387.pdf
Data publikacji:
2009-02
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
87.64.km
87.64.kp
87.64.Ee
87.85.jf
Opis:
Vibrational spectroscopy has been extensively used for in vitro and in vivo investigations of degradation mechanism and kinetics of different biomedical materials as well as it has been used to characterize the crystalline and amorphous domains in bio-mineralization process. Infrared and Raman spectroscopy methods are valuable tools in the biomaterials engineering allowing to study processes occurring during their preparation. In vitro tests, where the materials are immersed in simulated body fluids and/or artificial saliva, were used to evaluate the biocompatibility of biomaterials. This kind of tests are a wide range of repeatable and reproducible methods, which are regulated by international standards for commercial use and scientific development of new materials and products. The aim of this work was to examine phase composition of materials applied in dentistry. The bioactivity of such biomaterials was studied by immersing the samples in synthetic body fluid and artificial saliva. The changes were determined by the Fourier transform infrared and Raman microspectroscopy as well as scanning electron microscopy. It was found that results obtained by vibrational spectroscopy show the differences between the studied samples. Chemical reactions occurring during incubation of cements in artificial saliva as well as in synthetic body fluid result in formation of phosphates which deposit on the cement surface.
Źródło:
Acta Physica Polonica A; 2009, 115, 2; 533-536
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Synchrotron Radiation: New Trend in X-Ray Mammography
Autorzy:
Burattini, E.
Powiązania:
https://bibliotekanauki.pl/articles/1963348.pdf
Data publikacji:
1997-04
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
87.59.Ek
07.85.Qe
Opis:
In order to exploit the peculiar characteristics of synchrotron radiation for X-ray mammography purposes, monochromatic X-ray beams of selected energies from 16 keV to 22 keV have been used for the first time ever to obtain mammograms of surgically removed breast specimens containing cancer nodules. The apparatus devised particularly in view of a possible clinical applications, allowed large breast specimens fixed in space to be exposed to a vertical scanning X-ray beam. The mammograms obtained with synchrotron radiation, compared with those made using a traditional mammographic unit had higher contrast and better resolution demonstrating, in all the cases studied, a high capability to display a large number of structures inside the neoplastic lesions. Thermoluminescent dosimeters were used to determine the doses. The average mean glandular doses, at 17 keV and 18 keV, were 1.56 mGy and 0.84 mGy, respectively, comparable with the value of 1.41 mGy delivered with the conventional grid apparatus.
Źródło:
Acta Physica Polonica A; 1997, 91, 4; 707-713
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Bioimaging with 4th Generation X-Ray Sources
Autorzy:
Pełka, J.
Powiązania:
https://bibliotekanauki.pl/articles/1809941.pdf
Data publikacji:
2009-02
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
87.59.-e
41.60.Cr
07.85.Qe
82.53.Ps
87.64.Bx
Opis:
Newly constructed 4th generation sources of intense synchrotron radiation in ultrafast pulses of only 10-50 fs and wavelengths up to X-rays, the free electron lasers, are expected to revolutionize development of biological science. To take full advantage of unique properties of the sources, new imaging techniques of molecular and microscopic biological objects are developed. Present article provides a short review of a stormy development of bioimaging with incoming soon 4th generation synchrotron radiation X-ray sources. Some implications for the future of new sources and techniques are discussed as well.
Źródło:
Acta Physica Polonica A; 2009, 115, 2; 572-575
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Micromechanics Investigation of Wood Cell Walls under Compression Loading
Autorzy:
Günay, E.
Golmohammadi, H.
Powiązania:
https://bibliotekanauki.pl/articles/1398697.pdf
Data publikacji:
2016-04
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
87.85.gp
87.17.Rt
83.80.Lz
68.37.Ps
02.70.Dh
87.16.Gj
Opis:
The aim of this study was to detect the determinations of the 3D cell deformations of pine wood (Pinus sylvestris L.) in micro-scale(µm) under mechanical compression loading. The 20× 20× 50 mm³ sized wood specimens were tested under compressive pressure load through 35-40 MPa parallel to the grain orientations. The pressure applied samples were divided into three parts, then processed to form smaller cubic pieces and this pieces stained with gold liquid in order to get scanning electron microscopy images (12× 12× 12 mm^3 parts). The deformed cells were photographed in 3D-plane with magnification of (100×), (1500×) and in the range of 3.0-5.0 kV light voltage under the scanning electron microscope. Unloaded and loaded pine wood specimens were visualized and photographed to observe and examine the contraction or expansion of the cell walls comparatively. Based on the experimentally obtained microstructural permanent deformations of the cell structures, a numerical model had been proposed to explain the complex behaviour of cell structures under compression loading. Using the finite element method and ANSYS code, the permanent deformation ratios of three different pinewood cell models were simulated for 35-40 MPa loading to explain the overall stiffness and strength of the pinewood cells. In this way, by considering the results obtained from scanning electron microscopy measurements and related finite element analysis solutions, permanent deformation of honeycomb type pinewood cells was examined in detail.
Źródło:
Acta Physica Polonica A; 2016, 129, 4; 459-463
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Surface Texturing of Vitamin E Blended UHMWPE for Reduction of Wear
Autorzy:
Sagbas, B.
Durakbasa, M.
Powiązania:
https://bibliotekanauki.pl/articles/1182858.pdf
Data publikacji:
2014-02
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
87.85.J-
Opis:
Ultra high molecular weight polyethylene (UHMWPE) has been the most commonly used bearing material in artificial hip and knee replacements. But wear and wear debris of UHMWPE has been the most important problem which cause aseptic loosening and revision surgery of these replacements. For enhangement of wear resistance, new generation UHMWPE materials have been developed and different surface modification techniques have been tried. The objective of this study is to determine the effect of surface dimples on wear behavior of conventional UHMWPE and vitamin E blended UHMWPE (VE-UHMWPE) in ultra-pure water lubrication conditions. Pin-on-disc tribotester was used for measurement of friction coefficient and wear. 0.5 mm in diameter dimples were machined on the surfaces of UHMWPE and VE-UHMWPE discs. CoCrMo pins were used as counter surface. Results were evaluated in terms of materials and presence of dimples.
Źródło:
Acta Physica Polonica A; 2014, 125, 2; 481-483
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Titanium Surface Modification with Carbon Nanotubes. Towards Improved Biocompatibility
Autorzy:
Benko, A.
Wiecheć, A.
Rajchel, B.
Długoń, E.
Błażewicz, M.
Powiązania:
https://bibliotekanauki.pl/articles/1398806.pdf
Data publikacji:
2016-02
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
68.37.Hk
78.30.Na
81.15.Pq
82.45.Mp
87.85.J-
87.85.Rs
Opis:
Subject of this study is surface modification of titanium with thin layers of carbon nanotubes, obtained via an electrophoretic deposition, as a means to improve metal's biocompatibility and provide a suitable matrix for very facile further modifications, if needed. Article presents a preliminary evaluation of the material, using goniometer, scanning electron microscopy and the Raman spectroscopy. The layer is found to be composed of randomly distributed, strongly adhered carbon nanotubes, introducing nanotopography to the surface of titanium. Biological studies were conducted with the human osteoblast-like cell line MG63. Biocompatibility of materials was evaluated using: (a) lactate dehydrogenase cytotoxicity test (LDH) and (b) γ -H2AX genotoxicity test (presence of DNA double strand breaks). Results confirmed non-toxic character of the tested materials. Moreover, carbon nanotubes layers enhanced the biocompatibility properties of titanium substrate - material with carbon nanotubes possessed lower cellular toxic properties even than pure titanium. The result of this preliminary study are very promising and may serve as a starting point for further studies, including further chemical or biological modification of the obtained materials.
Źródło:
Acta Physica Polonica A; 2016, 129, 2; 176-178
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Biomedical Applications of Synchrotron X-Ray Fluorescence
Autorzy:
Kwiatek, W. M.
Powiązania:
https://bibliotekanauki.pl/articles/1931695.pdf
Data publikacji:
1994-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
07.85.+n
87.59.-e
32.30.Rj
Opis:
Since the exact role of trace elements in living organisms is still not very well known, it is a need of a careful analysis and study on trace element distributions in various biomedical materials. The conventional techniques such as X-ray fluorescence, proton-induced X-ray emission, atomic absorption spectrophotometry do not always give precise determination, especially in microstructures areas. Since synchrotron radiation is very powerful and gives the opportunity to work with micro-beams the synchrotron radiation induced X-ray emission technique has been recently developed. Due to many properties of synchrotron radiation it becomes a very useful tool in science. In this paper a characterization of different apparatus for a trace element analysis as well as several applications are described to show the usefulness of the synchrotron radiation induced X-ray emission.
Źródło:
Acta Physica Polonica A; 1994, 86, 5; 695-703
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:
Effect of Precipitation Method on Properties of Hydroxyapatite Powders
Autorzy:
Hazar Yoruç, A.
Karakaş, A.
Ayas, E.
Koyun, A.
Powiązania:
https://bibliotekanauki.pl/articles/1399899.pdf
Data publikacji:
2013-02
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
87.85.J-
Opis:
The aim of this study was the compare the properties of hydroxyapatite as a function of two different methods (chemical and biomimetic precipitation). Powder products were called as chemical hydroxyapatite for chemical method and biomimetic hydroxyapatite for biomimetic method. Precipitated powders with both methods were characterized by Fourier transform infrared, X-ray diffraction, X-ray fluorescence and measurements of hardness and density. Chemical analysis results showed that dried-biomimetic hydroxyapatite sample consists of hydroxyapatite $[Ca_{10}PO_4)_6(OH)_2]$ as main phase and beta-tricalcium phosphate (β-TCP) as secondary phase and dried-chemical hydroxyapatite sample also includes pure hydroxyapatite phase. Chemical hydroxyapatite and biomimetic hydroxyapatite powders were sintered using by spark plasma sintering method. Vickers hardness values of sintered disk samples were measured. Furthermore chemical structure of the final products was analyzed. Also density values of chemical hydroxyapatite and biomimetic hydroxyapatite disks were measured. Finally it is concluded that different precipitation methods affect hydroxyapatite properties and this can be an advantage for biomedical applications.
Źródło:
Acta Physica Polonica A; 2013, 123, 2; 371-373
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Genotoxicity Study of Carbon Nanoforms using a Comet Assay
Autorzy:
Panek, A.
Frączek-Szczypta, A.
Długoń, E.
Nocuń, M.
Paluszkiewicz, C.
Błażewicz, M.
Powiązania:
https://bibliotekanauki.pl/articles/1030655.pdf
Data publikacji:
2018-02
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
87.85.jj
87.14.gk
61.48.De
Opis:
Carbon nanoforms due to their unique properties can be applied in many areas also in medicine. This article presents preliminary genotoxicity studies of electrospun carbon nanofibers (ECNF). This material, apart from its numerous applications, may also be a candidate for use in medical therapy and diagnostics. Polyacrylonitrile (PAN) nanofibers received in the electrospinning process were carbonized and thereafter subjected to oxidation treatment (ECNF-F). Both types of fibres were analyzed with regard to genotoxic influence on the fibroblast line cells using comet assay. Additionally, comet assay experiments were conducted on biocompatible carbon nanotubes with a hydrophilic surface. The results indicate the key role of the oxidation process in the functionalization of carbon nanoparticles intended for medical purposes.
Źródło:
Acta Physica Polonica A; 2018, 133, 2; 306-308
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:
Prompt-Gamma Monitoring of Proton- and Carbon-Therapy. Combined Development of Time-of-Flight Collimated- and Compton-Cameras
Autorzy:
Dauvergne, D.
Freud, N.
Krimmer, J.
Létang, J.
Testa, E.
Powiązania:
https://bibliotekanauki.pl/articles/1402603.pdf
Data publikacji:
2015-05
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
29.40.Mc
07.85.Fv
87.53.Bn
87.56.Fc
87.56.-v
Opis:
Prompt-gamma imaging during ion therapy has proven its ability to control the ion range in real time. The achievable precision is of the order of the millimeter for a single spot in proton pencil beam scanning. Collimated gamma cameras have been developed, that are close to clinical application. The Compton cameras are also under development in various laboratories. Time of flight enables the reduction of the background due to other prompt radiations.
Źródło:
Acta Physica Polonica A; 2015, 127, 5; 1445-1448
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
An in Vitro Comparison of the Enamel Remineralisation Potential of Bioactive Glass, Hydroxyapatite and CPP-ACP
Autorzy:
Güçlü, Z.
Gjorgievska, E.
Coleman, N.
Powiązania:
https://bibliotekanauki.pl/articles/1033584.pdf
Data publikacji:
2017-03
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
87.85.J-
Opis:
The objective of this research was to investigate the comparative in vitro enamel remineralisation potential of commercial toothpastes containing bioactive glass (BG) particles, hydroxyapatite (HAP) particles or casein phosphopeptide - amorphous calcium phosphate (CPP-ACP) nanocomplexes. Eighteen extracted permanent teeth were coated with varnish leaving a window on the buccal surface and placed in demineralising solution for 24 h to create artificial caries-like white spot lesions (WSLs). The teeth were randomly assigned to six groups and sectioned longitudinally through the WSLs. The roots were removed and the teeth were re-varnished, leaving the WSLs exposed. Groups A, B and C were subjected to an optimum remineralisation protocol in which the "control" half of each tooth was incubated in artificial saliva for 24 h at 37°C and the "treatment" half of each corresponding tooth was cyclically exposed to artificial saliva and to 1:2 toothpaste solution containing either BG, HAP or CPP-CAP, respectively. Groups D, E and F were subjected to an acid-challenge remineralisation protocol which was similar to that of Groups A, B and C but which also incorporated cyclic exposure to demineralising solution. Scanning electron microscopy and energy dispersive X-ray analysis were used to compare the remineralisation of the surface and depth of the control and treatment WSLs. Under optimum conditions BG and CPP-ACP provided sub-surface repair by diffusion of calcium and phosphate ions into the WSLs. HAP did not influence remineralisation under neutral pH conditions. Conversely, under acid-challenge conditions, HAP was able to dissolve to release calcium and phosphate ions which diffused in to the WSLs and also protected the enamel surface from further erosion. BG and CPP-ACP both coated the enamel surface under acidic conditions, although their ability to remineralise the body of the lesion was compromised at low pH.
Źródło:
Acta Physica Polonica A; 2017, 131, 3; 571-575
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
TUY 40 Telescope Control System Based on LabVIEW
Autorzy:
Dindar, M.
Dindar, S.
Kandemir, E.
Bayar, C.
Helhel, S.
Ozisik, T.
Powiązania:
https://bibliotekanauki.pl/articles/1402539.pdf
Data publikacji:
2015-08
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
95.55.Cs
87.85.St
Opis:
Events and transients are becoming more and more crucial in modern astronomy such as supernovae, gamma-ray bursts and so on. VOEvent messages have all information to make the follow-up observations for transients and events which forces the scientists to make robotic observations. Robotic autonomous telescopes usually run under the control of a scheduler, which provides high-level control by selecting astronomical targets for observation. TUY 40 is a new robotic autonomous telescope control system designed by TÜBİTAK National Observatory (TUG). TUY 40 is based on 16 inch Meade LX-200 telescope mount and optical tube without any Meade electronic components and drive motors. The telescope control software developed on open-source Talon software and LabVIEW is presented. The algorithm for telescope control (slewing, tracking, homing etc.) was implemented in National Instruments PXI chassis written in LabVIEW real-time software from scratch. Talon is open-source software based on the GNU/C UNIX platform. A new TCP/IP library was implemented within Talon software to communicate with hard real-time telescope control software in LabVIEW PXI chassis. Initial setup without any permanent pier and polar alignment showed that the pointing error of the telescope has been obtained as 2.22 arcmin (132 arcsec) in RA axis (horizontal axis of the image) and 25 arcsec in Dec axis (vertical axis of the image), and tracking error has been observed as ≈ 4.8 arcsec per second.
Źródło:
Acta Physica Polonica A; 2015, 128, 2B; B-73-B-74
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Nanomechanical behaviour and surface roughness of new generation dental fissure sealants
Autorzy:
Arslanoğlu, Z.
Altan, H.
Kale, E.
Bılgıç, F.
Şahin, O.
Powiązania:
https://bibliotekanauki.pl/articles/1068318.pdf
Data publikacji:
2016-07
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
87.85.J-
62.20.-x
Opis:
The aim of this study is the comparative evaluation of surface roughness, elastic modulus and hardness values of some new generation fissure sealants using nanoindentation method and triboindenter. In this study, we have tested five different materials of dental fissure sealant in five groups with six specimens in each. Tested specimens were prepared from the following materials; Fuji Triage as a glass ionomer, Glass Seal as a glass carbomer, Ultra Seal XT Hydro, Teethmate F-1 and Defence Chroma as three resin composites. In the study, Hysitron Triboindenter TI 950 machine was used for nanohardness measurements. This machine has load resolution of less than 1 nN and displacement resolution of 0.04 nm. Data were statistically analysed using one-way analysis of variance (ANOVA) and Kolmogorov-Smirnov Z tests. Hardness values of Fuji Triage, Glass Seal, Ultra Seal XT Hydro were fairly close. Same situation was seen between Teethmate F-1 and Defence Chroma. However, hardness values of the Teethmate F-1 and Defence Chroma was lower than in other examined materials. We can also say that the Defence Chroma has the lowest elastic modulus and Fuji Triage has the highest one among the examined materials. Surface of Teethmate F-1 was the roughest. On the other hand, Ultra Seal XT Hydro has the smoothest surface.
Źródło:
Acta Physica Polonica A; 2016, 130, 1; 388-393
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Comparison of Microstructural and Mechanical Properties of Hydroxyapatite-Al₂O₃ Composites with Commercial Inert Glass (CIG) Addition
Autorzy:
Bulut, B.
Demirkol, N.
Erkmen, Z.
Kayali, E.
Powiązania:
https://bibliotekanauki.pl/articles/1401291.pdf
Data publikacji:
2015-04
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
87.85.J
Opis:
Hydroxyapatite (HA) is one of the most widely used biomaterials for orthopedic and dental applications. However, HA is a brittle and weak material and this constrains its orthopedic applications. There are several methods for the improvement of mechanical properties of the HA. One of these methods is to strengthen the HA material by a secondary phase (i.e polymer, metal or ceramics), to make a stronger composite material. Alumina (Al₂O₃) is a bioinert material, which has been widely investigated as a reinforcing agent for HA. The aim of this study is to compare the microstructural and mechanical properties of HA-Al₂O₃ composites with the addition of 5 and 10 wt.% of commercial inert glass (CIG). The grain samples were produced according to BS 7253 at 350 MPa. Then, they were sintered at temperatures between 1000-1300°C for 4 hours. The samples were also analyzed by SEM + EDS to determine microstructural properties, phase analysis was done by X-ray diffractometer (XRD), mechanical properties were measured by compression and hardness tests. Results show that HA-Al₂O₃ composites with addition of 5 and 10 wt.% CIG have reached high density values and high mechanical properties, such as compression strength and hardness at 1300°C. The compression strength and hardness of composites has increased with the increasing CIG content.
Źródło:
Acta Physica Polonica A; 2015, 127, 4; 1094-1096
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
In Vitro Bioactivity Study of Pure Wollastonite Prepared from Local Raw Materials
Autorzy:
Chehlatt, S.
Harabi, A.
Oudadesse, H.
Harabi, E.
Powiązania:
https://bibliotekanauki.pl/articles/1400570.pdf
Data publikacji:
2015-04
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
81.05.Je
81.05.Mh
87.85.jj
Opis:
CaSiO₃ ceramics have been proposed as a medical material for artificial bone and dental root, since they proved to be bioactive and biocompatible. In this study, CaSiO₃ powders were synthesized by mixing of Calcium oxide (CaO) and (SiO₂) for 3 h, and subsequent calcination of the mixture at 710°C for 2 h. The compacts were conventionally sintered at 1150°C for 2 h. Moreover, the in vitro bioactivity of wollastonite was investigated by soaking the powders in simulated body fluid (SBF) for various time periods to analyze the nucleation and growth of hydroxyapatite (HA) on the surface of the powders. The obtained results showed that hydroxy-carbonate-apatite (HCA) can be formed on the surface of α-CaSiO₃ particles soaked in SBF solution for 3 days, and a continuous layer of dense deposits of HCA covered the surface of α-CaSiO₃ powders after 15 days of soaking in SBF solution. Besides this, α-CaSiO₃ showed strong hydration when soaked in SBF solution and the hydration was favorable for formation of HCA. Finally, obtained results indicate that α-CaSiO₃ showed to be highly bioactive through the formation of homogeneous apatite layer.
Źródło:
Acta Physica Polonica A; 2015, 127, 4; 925-927
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Characterization of Cu/Ag/Eu/Hydroxyapatite Composites Produced by Wet Chemical Precipitation
Autorzy:
Komur, B.
Ozturk, E.
Ekren, N.
Inan, A.
Gunduz, O.
Andronescu, E.
Ficai, A.
Oktar, F.
Powiązania:
https://bibliotekanauki.pl/articles/1033469.pdf
Data publikacji:
2017-03
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
81.05.-t
81.05.Mh
87.85.J
Opis:
In the first part of this study hydroxyapatite was prepared synthetically through classical wet precipitation, using Ca(NO₃)₂·4H₂O (calcium nitrate tetrahydrate) as calcium source and HgN₂O4P as phosphate source. In the second part of the study HA compounds were prepared with different ratios (0.5, 1, 2, 5, 10 and 25 wt.%) of antibacterial materials like copper (Cu), silver (Ag) and europium (Eu), using the same wet precipitation method. The prepared pure HA material was utilized as the control group for comparison with Cu/Ag/Eu/HA composites. Studies of X-ray diffraction, FTIR spectroscopy, scanning electron microscopy, equipped with energy dispersive X-ray analysis were performed. The aim of this study was to investigate Cu/Ag/Eu/HA composites and the effect of metals on HA biomaterials, used as scaffold materials in bone disease treatment.
Źródło:
Acta Physica Polonica A; 2017, 131, 3; 392-396
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Hydroxyapatite Synthesis from Fish Bones: Atlantic Salmon (Salmon Salar)
Autorzy:
Komur, B.
Altun, E.
Aydogdu, M.
Bilgiç, D.
Gokce, H.
Ekren, N.
Salman, S.
Inan, A.
Oktar, F.
Gunduz, O.
Powiązania:
https://bibliotekanauki.pl/articles/1032056.pdf
Data publikacji:
2017-03
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
87.85.jj
81.05.-t
Opis:
Production of the bioceramics on the market is presently conducted from typical precipitation method by using reagent grade raw chemicals or through calcination of natural sources like animal bones (especially bovine bone) and fish bones. Usually fish bones were damped near or in the water sources, which can lead to serious environmental pollution. Those were regarded as a trash, even though they still bear economic value, including conjugates. In this study bones of Atlantic Salmon (Salmo salar) were used as a bioceramic material source. Bones of Atlantic Salmon were collected from Besiktas Fish Market. Those were cleaned from possible flesh with reagent grade NaOH. Cleaned parts were washed with demineralized water very neatly. Dry fish bones were calcinated at 850°C for 4 hours. The obtained hydroxyapatite material was characterized with scanning electron microscopy and X-ray diffraction methods. It was found that the bioceramic material consisted of hydroxyapatite and various related phases. Scanning electron microscopy studies have revealed nano-structured bioceramic particles. The aim of this study is to obtain nano-structured bioceramics from bones of Atlantic Salmon in an environmentally friendly and economic way.
Źródło:
Acta Physica Polonica A; 2017, 131, 3; 400-402
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Structure and Magnetic Properties of Nanocrystalline Fe-Mo Alloys Prepared by Mechanosynthesis
Autorzy:
Karolus, M.
Jartych, E.
Oleszak, D.
Powiązania:
https://bibliotekanauki.pl/articles/2035497.pdf
Data publikacji:
2002-08
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
61.10.Eq
07.85.Jy
81.07.Bc
81.07.Wx
61.18.Fs
87.64.Pj
Opis:
Nanocrystalline samples of Fe$\text{}_{80}$Mo$\text{}_{20}$ and Fe$\text{}_{50}$Mo$\text{}_{50}$ alloys were prepared by the mechanical milling method. The structure, lattice parameters, and crystallite size were determined by the X-ray diffraction. The magnetic properties of the milled products were determined by the M"ossbauer spectroscopy. It was observed that in the case of the Fe$\text{}_{80}$Mo$\text{}_{20}$ alloy a solid solution of Mo in Fe was formed with the lattice parameters of Fe increasing from 0.28659 nm to 0.29240 nm and the crystallite size decreasing from 250 nm to 20 nm. In the case of the Fe$\text{}_{50}$Mo$\text{}_{50}$ alloy there were no clear changes in values of the lattice parameters of Fe and Mo during the milling process, but the crystallite size decreased from 200 nm to 15 nm. Mössbauer spectra revealed different magnetic phases in the mechanosynthesized Fe-Mo samples. In the case of the Fe$\text{}_{80}$Mo$\text{}_{20}$ alloy, the spectrum for the milled mixture indicated the formation of a solid solution. In contrast, for the Fe$\text{}_{50}$Mo$\text{}_{50}$ the spectrum indicated the disappearance of the ferromagnetic phase.
Źródło:
Acta Physica Polonica A; 2002, 102, 2; 253-258
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Structure of the Extruded and Thermally Treated $Ni_{54.3}Fe_{16.2}Ga_{29.5}$ Alloy
Autorzy:
Prusik, K.
Matyja, E.
Zubko, M.
Goryczka, T.
Powiązania:
https://bibliotekanauki.pl/articles/1398368.pdf
Data publikacji:
2016-10
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
81.30.Kf
87.64.Ee
81.30.Mh
83.85.Hf
71.20.Lp
71.20.Be
Opis:
Hot extrusion process was applied to $Ni_{54.3}Fe_{16.2}Ga_{29.5}$ polycrystalline alloy. Then the rod was annealed subsequently for 1 h at 700, 800, 900, and 1100°C. In this paper the effect of annealing on the microstructure of the polycrystalline extruded Ni-Fe-Ga alloy were analyzed. The structure of the alloys was determined by the X-ray and transmission electron microscopy. The electron backscattering diffraction technique was applied to obtain the texture of the extruded rods after heat treatment.
Źródło:
Acta Physica Polonica A; 2016, 130, 4; 1020-1022
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Interrelation of Microstructure and Corrosion Resistance in Biodegradable Magnesium Alloys with Aluminum, Lithium and Rare Earth Additions
Autorzy:
Minárik, P.
Landa, M.
Lesná, I.
Zemková, M.
Jablonská, E.
Hadzima, B.
Janeček, M.
Král, R.
Powiązania:
https://bibliotekanauki.pl/articles/1402061.pdf
Data publikacji:
2015-10
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
81.05.-t
82.45.Bb
87.85.J-
43.40.Le
Opis:
The influence of equal channel angular pressing and rotary swaging on the microstructure and corrosion resistance was investigated in three magnesium alloys with the addition of aluminum, lithium and rare earth elements - AE21, AE42 and LAE442. The processing resulted in grain refinement in all cases; nevertheless, the effect on the corrosion resistance was ambiguous. A continuous increase of the polarization resistance during the gradual equal channel angular pressing was observed in the AE42 and LAE442 alloys, whereas there was almost no effect in the AE21 alloy. The rotary swaging of AE42 resulted in a decrease of polarization resistance. The increase of polarization resistance in the alloys with the higher concentration of alloying elements was caused by the combined effect of grain refinement and better dispersion of particles in the matrix thanks to shear deformation during equal channel angular pressing. In the AE42 alloy, the increase of the corrosion resistance after equal channel angular pressing was also proven by chemical analysis of the solution and acoustic emission detection. This beneficial effect was not observed when the concentration of alloying elements was lower or when the deformation mode was different from shearing.
Źródło:
Acta Physica Polonica A; 2015, 128, 4; 491-496
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Analysis Framework for the J-PET Scanner
Autorzy:
Krzemień, W.
Gajos, A.
Gruntowski, A.
Stola, K.
Trybek, D.
Bednarski, T.
Białas, P.
Czerwiński, E.
Kamińska, D.
Kapłon, Ł.
Kochanowski, A.
Korcyl, G.
Kowal, J.
Kowalski, P.
Kozik, T.
Kubicz, E.
Moskal, P.
Niedźwiecki, Sz.
Pałka, M.
Raczyński, L.
Rudy, Z.
Salabura, P.
Sharma, N.
Silarski, M.
Słomski, A.
Smyrski, J.
Strzelecki, A.
Wieczorek, A.
Wiślicki, W.
Zieliński, M.
Zoń, N.
Powiązania:
https://bibliotekanauki.pl/articles/1402621.pdf
Data publikacji:
2015-05
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
87.57.nf
87.57.uk
29.85.-c
Opis:
J-PET analysis framework is a flexible, lightweight, ROOT-based software package which provides the tools to develop reconstruction and calibration procedures for PET tomography. In this article we present the implementation of the full data-processing chain in the J-PET framework which is used for the data analysis of the J-PET tomography scanner. The framework incorporates automated handling of PET setup parameters' database as well as high level tools for building data reconstruction procedures. Each of these components is briefly discussed.
Źródło:
Acta Physica Polonica A; 2015, 127, 5; 1491-1494
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Applications of a compact "water window" source for investigations of nanostructures using SXR microscope
Autorzy:
Torrisi, A.
Wachulak, P.
Fahad Nawaz, M.
Bartnik, A.
Adjei, D.
Vondrová, Š.
Turňová, J.
Jančarek, A.
Fiedorowicz, H.
Powiązania:
https://bibliotekanauki.pl/articles/1065141.pdf
Data publikacji:
2016-02
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
52.38.-r
42.30.-d
42.62.-b
87.59.-e
68.37.Yz
07.85.Tt
41.50.+h
42.79.Dj
Opis:
A compact soft X-ray microscope based on a nitrogen double-stream gas puff target soft X-ray source, operating at He-like nitrogen spectral line at the wavelength of λ =2.88 nm is presented. The desk-top size microscope was successfully demonstrated in transmission mode using the Fresnel zone-plate objective and it is suitable for soft X-ray source microscopy in the "water window" spectral range (λ = 2.3÷ 4.4 nm). Details about the soft X-ray source source, the microscope and an example of application in the biomedical field are shown and discussed.
Źródło:
Acta Physica Polonica A; 2016, 129, 2; 169-171
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Bivalve Characterization Using Synchrotron Micro X-Ray Fluorescence
Autorzy:
Jones, K.
Bronson, S.
Brink, P.
Gordon, C.
Mosher-Smith, K.
Brown, M.
Chaudhry, S.
Rizzo, A.
Sigismondi, R.
Whitehurst, M.
Lukaszewski, A.
Kranz, D.
Bland, K.
Gordan, D.
Lobel, J.
Sullivan, J.
Metzger, M.
O'Shea, C.
Harris, C.
Arezzo, R.
Kambhampati, M.
Powiązania:
https://bibliotekanauki.pl/articles/1808352.pdf
Data publikacji:
2009-02
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
01.40.-d
07.85.Qe
82.80.Ej
87.59.-e
Opis:
Bivalves, oysters, mussels, and clams are important constituents of riverine and estuarine ecosystems. Their shells and soft tissues provide information on the environments in which they live. Since they are filter feeders, they also are factors in improving water quality through removal of particulate matter from the water column. Finally, they are a valuable food source that has substantial economic value. Hence, characterization of shells and soft tissues is useful for improved understanding of these factors. Here, we used X-ray microprobes and computed microtomography facilities at the Brookhaven National Synchrotron Light Source to investigate elemental distributions in bivalves taken from locations around New York, Washington, DC, and New Orleans, LA. The results form the initial basis for compilation of a database of relevant parameters that can serve for tracking environmental changes and for assessing toxicity of particular metals. The work was enabled by active collaboration with students from the several regions, community groups, and research scientists. The collaboration was facilitated through use of web conferencing between Brookhaven National Laboratory and the varied locations.
Źródło:
Acta Physica Polonica A; 2009, 115, 2; 477-481
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A Method to Produce Linearly Polarized Positrons and Positronium Atoms with the J-PET Detector
Autorzy:
Mohammed, Muhsin
Białas, P.
Curceanu, C.
Czerwiński, E.
Dulski, K.
Gajos, A.
Głowacz, B.
Gorgol, M.
Hiesmayr, B.
Jasińska, B.
Kisielewska, D.
Korcyl, G.
Kowalski, P.
Kozik, T.
Krawczyk, N.
Krzemień, W.
Kubicz, E.
Pawlik-Niedźwiecka, M.
Niedźwiecki, S.
Pałka, M.
Raczyński, L.
Raj, J.
Rudy, Z.
Sharma, N.
Sharma, S.
Shivani, ---
Skurzok, M.
Silarski, M.
Wieczorek, A.
Wiślicki, W.
Zgardzińska, B.
Zieliński, M.
Moskal, P.
Powiązania:
https://bibliotekanauki.pl/articles/1030045.pdf
Data publikacji:
2017-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
41.75.Fr
41.75.Ht
77.22.Ej
36.10.Dr
85.75.Mm
87.57.uk
Opis:
A method for creating linearly polarized positrons and ortho-positronium (o-Ps) atoms with the J-PET detector is presented. The unique geometry and properties of the J-PET tomography enable one to design a positron source such that the quantization axis for the estimation of the linear polarization of produced o-Ps can be determined on the event by event basis in a direction of the positron motion. We intend to use ²²Na or other β⁺ decay isotopes as a source of polarized positrons. Due to the parity violation in the beta decay, the emitted positrons are longitudinally polarized. The choice of the quantization axis is based on the known position of the positron emitter and the reconstructed position of the positronium annihilation. We show that the J-PET tomography is equipped with all needed components.
Źródło:
Acta Physica Polonica A; 2017, 132, 5; 1486-1489
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
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