Degradation of mechanical properties of magnesium alloy
Sedláček, R.; Suchý, Tomáš; Padovec, Z.
2019 - English
In this study, biodegradation behaviour of WE43 magnesium alloy have been studied and compared during exposure to three different media commonly used to simulate the conditions of human body environment. Magnesium alloys emerged as a new class of bioresorbable implant materials. Their applications reduce certain risks associated with conventional permanent implants. Biodegradation behaviour of the WE43 magnesium alloy was observed under Dulbecco Modified Eagle Medium (DMEM, Sigma Aldrich) supplemented with 5 % fetal bovine serum and gentamicin antibiotic as standard. The samples were stored in the medium at 37 degrees C and in a 5 % CO2 atmosphere. The second type of medium was Hank's Salt Balanced Solution (HBSS, Sigma Aldrich), which simulates the inorganic composition of blood plasma. HBSS was tempered at 37 degrees C. The last solution was an acidic solution of HCl + NaCl (pH2) with pH similar to 2 (0.01M HCl and 0.14M NaCl) tempered at 37 degrees C. The acidic type of solution was used to simulate a local acidic environment associated with osteoclast activity during bone remodelling. Changes in the mechanical properties of the samples during exposure to simulated body conditions were observed.
Keywords:
Bioabsorbable metals; Biodegradation; Magnesium; Implant
Available at various institutes of the ASCR
Degradation of mechanical properties of magnesium alloy
In this study, biodegradation behaviour of WE43 magnesium alloy have been studied and compared during exposure to three different media commonly used to simulate the conditions of human body ...
Mechanical and structural properties of collagen nanofribrous layers under simulated body conditions
Říhová, J.; Suchý, Tomáš; Vištejnová, L.; Horný, L.; Šupová, Monika
2019 - English
The theme of this paper is the analysis of mechanical and structural properties of nanofibrous COL under simulated body conditions and in the presence of osteoblasts and dermal fibroblasts. COL were prepared by electrostatic spinning of 8 wt% collagen type I dispersion with 8 wt% (to COL) of PEG in phosphate buffer/ethanol solution (1/1 vol). The stability of COL was enhanced by means of cross-linking with EDC and NHS at a molar ratio of 4:1. COL were exposed in culture medium for 21 days and human SAOS-2 human dermal fibroblasts and osteoblasts were cultured therein for 21 days as well.
Keywords:
collagen; fibroblasts; osteoblasts; mechanical properties; structural properties; biodegradation
Available at various institutes of the ASCR
Mechanical and structural properties of collagen nanofribrous layers under simulated body conditions
The theme of this paper is the analysis of mechanical and structural properties of nanofibrous COL under simulated body conditions and in the presence of osteoblasts and dermal fibroblasts. COL were ...
Field measurement of natural electromagnetic emissions near the active tectonic and mass-movement fractures in caves
Trčka, T.; Macků, R.; Koktavý, P.; Škarvada, P.; Baroň, I.; Stemberk, Josef
2017 - English
Laboratory tests on a wide range of solid materials shoved that the electromagnetic emission (EME) signals are generated during the samples mechanical stress. EME anomalies have been observed also under natural conditions in association to fracture processes, tectonic loading, stress redistribution and crack propagation prior to earthquake or in relation to deep-seated gravitational mass movements. This paper describes a first prototype of the Emission data logger, which was specially developed for the continual EME monitoring in field conditions. Our equipment has been installed and tested in Obir Caves (Austria) at an active tectonic fault. The pilot long-term EME measurement results from this location are also presented in this paper.
Keywords:
Active tectonic fault; Continual monitoring; Emission data logger; Field measurement; Fracture processes; Natural electromagnetic emissions
Available at various institutes of the ASCR
Field measurement of natural electromagnetic emissions near the active tectonic and mass-movement fractures in caves
Laboratory tests on a wide range of solid materials shoved that the electromagnetic emission (EME) signals are generated during the samples mechanical stress. EME anomalies have been observed also ...
A COMPARISON OF THE CENTRIFUGAL FORCE SPINNING AND ELECTROSPINNING OF COLLAGEN UNDER DIFFERENT CONDITIONS
Hlavatá, J.; Suchý, Tomáš; Šupová, Monika; Pokorný, M.; Košťáková, E.
2017 - English
Collagen makes up one of the most important parts of the extracellular matrix and connective tissue. Collagen type I accounts for up to 90% of the collagen found in the body and it can be isolated and purified in large quantities and processed into a variety of forms. With respect to the process of the treatment of collagen into the nano-fibrous and submicron-fibrous forms, severe conditions leading to the denaturation of the collagen and thus the gelatin content should be avoided. Centrifugal force spinning and electrospinning processes appear to present promising methods for the spinning of collagen solutions. This paper deals with a comparison of the various methods applied in the processing of collagen, i.e. principally needle and needleless centrifugal spinning technology and electrospinning technology. In addition, the effect of process parameters and collagen solution conditions on the final form of the material was analyzed. Spun layers were prepared based on collagen type I isolated from calf skin. Nano-structured layers were prepared employing the spinning of 4-16 wt% collagen solutions in phosphate buffer saline and ethanol. The layers thus prepared were characterized by means of scanning electron microscopy and Fourier transform infrared spectroscopy.
Keywords:
collagen; electrospinning; centrifugal force spinning; triple-helix
Available at various institutes of the ASCR
A COMPARISON OF THE CENTRIFUGAL FORCE SPINNING AND ELECTROSPINNING OF COLLAGEN UNDER DIFFERENT CONDITIONS
Collagen makes up one of the most important parts of the extracellular matrix and connective tissue. Collagen type I accounts for up to 90% of the collagen found in the body and it can be isolated and ...
Hydrogen charging of fuel cladding methodology
Krejčí, J.; Kabátová, J.; Kočí, J.; Weishauptová, Zuzana; Vrtílková, V.
2016 - English
Hydrogen content is a very important parameter for mechanical properties of fuel cladding. The methodology of developed hydrogen charging is described.
Keywords:
fuel cladding; hydridation
Available at various institutes of the ASCR
Hydrogen charging of fuel cladding methodology
Hydrogen content is a very important parameter for mechanical properties of fuel cladding. The methodology of developed hydrogen charging is described.
A brief introduction to the geology of the Moldanubian batholith
Verner, K.; René, Miloš; Žák, J.; Janoušek, V.
2015 - English
Emplacement processes and tectonic setting of the Moldanubian batholith. The batholith consists of multiple intrusive units (plutons, stocks and dykes), predominantly composed of granitic to granodioritic rocks with either S- or transitional I/S-type.
Keywords:
granite; petrology; geochemistry; Bohemian Massif
Available at various institutes of the ASCR
A brief introduction to the geology of the Moldanubian batholith
Emplacement processes and tectonic setting of the Moldanubian batholith. The batholith consists of multiple intrusive units (plutons, stocks and dykes), predominantly composed of granitic to ...
Origin of “rock cities”, pillars and cleft-conduits in kaolinite-bonded sandstone: New insight from study in sandstone quarry where landforms recently evolve
Bruthans, J.; Soukup, J.; Schweigstillová, Jana; Vaculíková, J.; Smutek, D.; Mayo, A. L.; Falteisek, L.
2013 - English
Based on measurements of relative erodibility, ambient and water-saturated tensile strength at natural and quarry exposures three distinct kinds of surfaces were distinguished (erodible sandstone, sub-vertical fracture surfaces and case hardened surfaces). Erosion proceeded along highly fractured zones.
Keywords:
case hardening erosion; fluidization; overland flow; piping; sandstone landforms
Available at various institutes of the ASCR
Origin of “rock cities”, pillars and cleft-conduits in kaolinite-bonded sandstone: New insight from study in sandstone quarry where landforms recently evolve
Based on measurements of relative erodibility, ambient and water-saturated tensile strength at natural and quarry exposures three distinct kinds of surfaces were distinguished (erodible sandstone, ...
The Influence of Steam Sterilization Processes on the Micro- and Macromechanical Properties of Polyamide Fiber-Reinforced PDMS Composites for Medical Device Applications
Sochor, M.; Balík, Karel; Sedláček, R.; Suchý, Tomáš; Sucharda, Zbyněk; Šepitka, J.; Lukeš, J.
2012 - English
The effect of multiple steam sterilization processes on the structural integrity of the polymer matrix composite polydimethylsiloxane (PDMS) reinforced with polyamide fibers (Aramid) is investigated by 3- and 4-point bending tests and by nanoindentation.
Keywords:
composite material; sterilization; nanoindentation
Available at various institutes of the ASCR
The Influence of Steam Sterilization Processes on the Micro- and Macromechanical Properties of Polyamide Fiber-Reinforced PDMS Composites for Medical Device Applications
The effect of multiple steam sterilization processes on the structural integrity of the polymer matrix composite polydimethylsiloxane (PDMS) reinforced with polyamide fibers (Aramid) is investigated ...
Sterilization Decomposition Evaluation of Radiolucent Composite Materials for Use in Medicine
Sochor, M.; Balík, Karel; Suchý, Tomáš; Sedláček, R.; Sucharda, Zbyněk; Beneš, J.; Prokop, J.
2011 - English
This study evaluates the resistance against multiple sterilization processes of radiolucent composite materials for use in medicine as an intraoperative imaging device material. The composite materials under investigation here are composed of carbon fibers, polyphenylene sulfide and polyetheretherketone matrix. The influence of multiple sterilization processes on changes in their mechanical and structural properties are determined. The radiolucency of the proposed composites is verified.
Keywords:
composite material; sterilization decomposition; radiolucency
Available at various institutes of the ASCR
Sterilization Decomposition Evaluation of Radiolucent Composite Materials for Use in Medicine
This study evaluates the resistance against multiple sterilization processes of radiolucent composite materials for use in medicine as an intraoperative imaging device material. The composite ...
Pyrolysis of coal/waste plastic mixtures in cokemaking
Melegy, A.; Sýkorová, Ivana; Kříž, Vlastimil; Havelcová, Martina
2011 - English
In the recycling process of waste plastic using coke oven, sub-bituminous coal and added 5 vol. % of plastics are carbonized and changed into coke of optimal properties, tar and gas .
Keywords:
Maghara subbituminous coal; pyrolysis; coal/plastic waste blend
Available at various institutes of the ASCR
Pyrolysis of coal/waste plastic mixtures in cokemaking
In the recycling process of waste plastic using coke oven, sub-bituminous coal and added 5 vol. % of plastics are carbonized and changed into coke of optimal properties, tar and gas .
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