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1
Content available remote

Adherence Properties of Acrylic Bone Cement to Alumina Ceramics Designed for Clinical Applications

100%
Cavalu S., Simon V., Akin I., Goller G.
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vol. 125
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issue 2
603-605
EN
The aim of this study is to investigate the adherence properties of acrylic cement based on PMMA to alumina ceramics. These ceramics are suitable for orthopedic and dental applications, as bioinert components in prosthetic surgery. The surface of alumina specimens were subjected to a special treatment based on acid etched followed by two different fluoride treatments: SnF_2 and NaBF_4, respectively. The structural properties of Al_2O_3 specimens were investigated before any treatments by X-ray diffraction, Fourier transform infrared spectroscopy and scanning electron microscopy. The modification occurred after the chemical treatment was investigated by X-ray photoelectron spectroscopy. The adherence of commercial acrylic cement to both treated alumina specimens was evaluated by scanning electron microscopy upon transversal cutting of the specimens. The results demonstrated that SnF_2 is more favorable with respect to adhesion of PMMA based orthopedic cements.
2
Content available remote

Biodegradation Properties of Poly (Lactic) Acid Reinforced by Kenaf Fibers

100%
Surip S., Wan Jaafar W., Azmi N., Hassan N.
Acta Physica Polonica A
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2016
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vol. 129
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issue 4
835-837
EN
This study was conducted to study the degradation of poly (lactic acid) and its composites under natural landfill burial. Composites reinforced with natural fibres were expected to degrade faster than polymer itself. PLA was compounded with kenaf bast fibre (KBC) and kenaf core fibre (KCC) with twin screw extrusion at temperature range 150-160°C and being compression moulded at 170°C for 8 minutes. Samples were then cut prior to testing by burying under composting area in UiTM Shah Alam, Selangor, Malaysia for 6 month period. Samples were measured and observed monthly for the degradation of composites by weight loss and microscopic observation. As expected weight loss for kenaf bast composite (KBC) and kenaf core composite (KCC) was found to be higher, 15.9% and 17.1% respectively, than that of pure PLA of only 4.14%. Microscopic observation confirms degradation has occurred on surface of composites by making cracks, holes, and black spots on all samples, however degradation was more obvious on composites. FTIR analysis shows that spectra of exposed composites were reduced compared to those of unexposed composites.
3
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The Effect of Yttrium Oxide Reinforcement on the Microstructural and Mechanical Properties of Biologically Derived Hydroxyapatite

100%
Bozkurt Y., Gokce H., Pazarlioglu S., Salman S.
Acta Physica Polonica A
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2015
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vol. 127
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issue 4
1403-1406
EN
In the present study, hydroxyapatite used as a matrix material was derived from the femur bones of Meleagris gallapova (MGHA) and then reinforced with yttriyum oxide (Y₂O₃, 5 and 10 wt.%). Then samples pelleted at 350 MPa were sintered between 900 and 1300°C. Finally, the effect of Y₂O₃ reinforcement on the microstructural and mechanical properties of MGHA was investigated. Scanning electron microscope (SEM) and X-ray diffraction (XRD) patterns were used for microstructural examinations. Density, microhardness and compressive strengths of composites were used to analyze their mechanical properties. Experimental results show that mechanical properties of composites were enhanced by increasing the temperature. The optimum results were obtained for MGHA-10% Y₂O₃ composites sintered at 1200°C.
4
Content available remote

Hydroxyapatite Lanthanum Oxide Composites

100%
Bozkurt Y., Pazarlioglu S., Gokce H., Gurler I., Salman S.
Acta Physica Polonica A
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2015
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vol. 127
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issue 4
1407-1409
EN
In the present study a commercially synthetic hydroxyapatite powders (CSHAp) were doped with lanthanum oxide (5 and 10 wt.% La₂O₃). The composite powders were well homogenized and pelleted in an uniaxial mould at 350 MPa. Pelleted green bodies were sintered at five different temperatures. Finally, the effect of La₂O₃ amount on the microstructural and mechanical properties of CSHA was investigated. Microstructural properties were detected by X-ray diffraction patterns (XRD) and scanning electron microscope (SEM). Mechanical properties of the sintered samples were determined by the density, hardness and compression strength measurements. Experimental results show that the mechanical properties of HA can be improved by the doping of La₂O₃
5
Content available remote

Bioceramic Production from Sea Urchins

100%
Ağaoğullari D., Kel D., Gökçe H., Duman I., Öveçoğlu M., Akarsubaşi A., Bılgıç D., Oktar F.
Acta Physica Polonica A
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2012
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vol. 121
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issue 1
23-25
EN
Bioceramic nanopowders, currently one of the most demanding challenges for producing new biomaterials, have been tackled only when starting from chemical reagents. There are few studies aiming at producing hydroxyapatite nanopowders from naturally derived raw materials, such as nacre shells. Natural species of sea origin, such as corals and nacres, always attract special interest in biomaterials science and technology. Nacre shells are made up of pure aragonite crystallized in an organic matrix. The most common way to transform aragonite structures to hydroxyapatite is via hydrothermal transformation under very high pressure. However, such ways can be very dangerous if the equipment is worn. Ultrasonic and hotplate methods are apparently very safe. This work proposes a new approach for developing highly bioactive fine powders of Ca-phosphates (which can be used afterwards to build up hydroxyapatite-based bioceramic bone-scaffolds) from sea urchins via the above mentioned methods. The suspended raw powders were put on a hotplate (i.e. ultrasound). The temperature was set to 80C for 15 min and then, equivalent (to the amount of CaCO_3 in the sea urchins) amount of H_3PO_4 was added drop by drop into the solution. The reaction continued for 2 h. Then, to evaporate the liquid part, the mixture was put into an incubator at 100C for 24 h and the resultant dried sediment was collected. X-ray diffraction analysis identified various calcium phosphate phases, predominantly monetite, and tricalcium phosphate as a secondary phase. The worldwide availability and the low cost of all kinds of nacre and sea urchin shells, along with their biological-natural origin are attractive features conferring to them a high potential for preparing calcium phosphate materials for uses in biomedicine. Heart urchin, used in this study, can be an ideal candidate for producing bioceramic particles.
6
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Characterization of TiAlV Films Prepared by Vacuum Arc Deposition: Effect of Substrate Temperature

63%
Abdallah B., Mrad O., Ismail I.
Acta Physica Polonica A
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2013
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vol. 123
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issue 1
76-79
EN
Three TiAlV films have been prepared by vacuum arc discharge technique at different substrate temperatures (50, 300, and 400°C). The depositions were carried out from aluminum, vanadium and titanium elemental targets. The temperature effects on the crystalline quality and texture have been investigated by means of X-ray diffraction. Two phases have been identified and the grain size has been found to increase with temperature. The composition of the films has been determined by proton induced X-ray emission technique. The Ti ratio was found to increase with temperature. The microhardness, measured by the Vickers indentation method was found to decrease with temperature. X-ray photoelectron spectroscopy was used to study the chemical composition of the passive layer formed on the films by analyzing high resolution spectra of Al 2p, Ti 2p and V 2p. This layer was mainly composed of TiO_2 with a small participation of other oxidation and metallic states of Ti, Al and V.
7
Content available remote

Influence of Aging Procedure on Bonding Strength and Thermal Conductivity of Plywood Panels

63%
Demirkir C., Colakoglu G., Colak S., Aydin I., Candan Z.
Acta Physica Polonica A
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2016
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vol. 129
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issue 6
1230-1234
EN
Wood and wood composite materials have been used in house, school, and office construction throughout the world. Wood composite materials are superior to other building materials in terms of thermal conductivity due to its porous structure. Bonding strength and thermal conductivity are two of many other significant properties of composite panels used in construction. It was essential to determine the effect of ageing process on the properties of panels used in structural applications. This study evaluates thermal conductivity and bonding strength of Scots pine and black pine plywood panels manufactured from rotary cut veneers dried at three different temperatures: 110°C, 140°C, and 160°C. Phenol formaldehyde (PF) and melamine urea formaldehyde (MUF) were used as adhesives for plywood manufacturing. Panels were exposed to ageing process according to ASTM C 481-99 standard. Plywood panels with five plies and 10 mm thickness were manufactured for each group. Thermal conductivity and bonding strength values of plywood panels were determined. Thermal conductivity of the panels decreased with increase of the drying temperature. It was also found that the thermal conductivity of test panels decreased after the ageing process. Shear strength mean values obtained from the samples of all plywood panels were above the limit value (1.0 N/mm²) indicated in TS EN 314-2 standard but those of the panels with MUF after ageing process.
8
Content available remote

Magnetic Birefringence Study of the Magnetic Core Structure of Ferritin

51%
Koralewski M., Pochylski M., Mitróová Z., Melníková L., Kováč J., Timko M., Kopčanský P.
Acta Physica Polonica A
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2012
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vol. 121
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issue 5-6
1237-1239
EN
Magnetically induced optical birefringence (Δ n) was measured for magnetoferritin and horse spleen ferritin aqueous suspensions. The Δ n for magnetoferritin was described in the frame of the Langevin formalism taking into account distribution of core diameter. The established average magnetic dipole moment and core diameter is equal to about 460 μ_{B} and 3 nm, respectively. It was shown that magnetic birefringence and the Cotton-Mouton constant can be powerful parameters in identification of the magnetic core structure of ferritin, especially useful in biomedicine.
9
Content available remote

Application of μ-FTIR-SR Spectroscopy to Prostate Tissue Analysis

51%
Kwiatek W., Paluszkiewicz C., Banaś A., Kisiel A., Podgórczyk M., Marcelli A., Cestelli Guidi M., Piccinini M.
Acta Physica Polonica A
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2009
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vol. 115
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issue 2
602-605
EN
The infrared spectromicroscopy is a quite recent technique rapidly developing thanks to the availability of new instruments and new brilliant synchrotron radiation sources in different areas and in particular to biomedical researches. In order to achieve a diffraction limited spatial resolution in tissue samples, we performed experiments at SINBAD, the synchrotron infrared beamline of the Laboratori Nazionali di Frascati. We characterized the chemical composition of prostate tissue samples taken from patients affected by prostate cancer disease. Different sizes of the pinholes were considered for the measurements. In the case of prostate tissue sections the results show the possibility to determine the intensity ratio of the CH_2 and CH_3 bands set at 2930 cm^{-1} and 2960 cm^{-1}, respectively. Experiments were also performed with a pinhole of 5 μm of diameter and the differences in both histological and chemical compositions of such samples were determined.
10
Content available remote

Corrosion and Tribocorrosion Behavior of Cast and Machine Milled Co-Cr Alloys for Biomedical Applications

51%
Mindivan F., Yıldırım M., Bayındır F., Mindivan H.
Acta Physica Polonica A
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2016
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vol. 129
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issue 4
701-704
EN
In this study, the electrochemical behavior and tribocorrosion performance of cobalt-chromium (Co-Cr) alloys produced by different fabrication methods (casting and CAD/CAM milling technique) have been investigated in the laboratory-simulated artificial saliva. The results have shown that the maximum tribocorrosion resistance was obtained for milled Co-Cr alloy because of higher corrosion resistance and hardness of milled Co-Cr alloy compared too those of cast Co-Cr alloy. Moreover, the lowest friction coefficient was achieved for milled Co-Cr alloy.
11
Content available remote

Surface Study of Selected Biomaterials Using Vibrational Spectroscopy

51%
Paluszkiewicz C., Kwiatek W., Długoń E., Wesełucha-Birczyńska A., Piccinini M.
Acta Physica Polonica A
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2009
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vol. 115
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issue 2
533-536
EN
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.
12
Content available remote

Elaboration and Characterization of Bioceramics from Natural Phosphate

51%
Belhouchet H., Sahnoune F., Heraiz M.
Acta Physica Polonica A
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2017
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vol. 131
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issue 1
117-119
EN
The aim of this work is the substitution of the bovine bone by the natural phosphate from Djebelel-Onk (Tébessa, East of Algeria). We prepared two composites (bone/Al₂O₃ and natural phosphate/Al₂O₃) by reaction sintering. Different experimental techniques, including density, porosity, X-rays diffraction, and SEM techniques, were used to analyze the formation and transformation of phases at different temperatures. From the X-ray diffraction patterns, we put in evidence the formation of several phases. Through these results, we lighted the possibility of preparing bioceramics from natural phosphate (bone and natural phosphate). The presence of the different materials was confirmed by the micrographic observations.
13
Content available remote

Differentiation of Native and Reconstructed Ferritin using the MRI Gradient Echo Pulse Sequence

45%
Balejcikova L., Strbak O., Baciak L., Kovac J., Masarova M., Krafcik A., Kopcansky P., Dobrota D., Frollo I.
Acta Physica Polonica A
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2017
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vol. 131
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issue 4
1093-1095
EN
Ferritin is a biological iron storage biomacromolecule, consisting of a spherical protein shell (apoferritin) and mineral iron core. It plays a crucial role in the pathological processes of disrupted iron homeostasis followed by iron accumulation, linked with various disorders (e.g. neuroinflammation, neurodegeneration, cirrhosis, cancer, etc.) In vitro reconstructed ferritin, with the assistance of a non-invasive magnetic resonance imaging technique, has the potential to become a suitable biomarker of these pathological processes. Through gradient echo pulse sequencing, we were able to clearly distinguish between native (physiological) and reconstructed/iron-overloaded (pathological) ferritin, which can serve as a starting point for the development of a method for their differentiation. Such method is necessary for the early diagnosis of iron-based diseases.
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