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1
Content available ZrO2 Gelcast Foams Coated with Apatite Layers
EN
In this work, gel-casting of foams method was used to produce ZrO2 porous ceramics. The obtained foams with total porosity of 89.5 vol% were composed of approximately spherical cells having the mean diameter of 537 ± 153 μm interconnected by circular cell windows having the mean diameter of 152 ± 82 μm. Next, the ZrO2 foams were coated with fluorapatite (FA) and hydroxyapatite (HA) layers by slurry infiltration. The intermediate fluorapatite (FA) layer was introduced to prevent the chemical reactions between ZrO2 and HA at high temperatures during sintering process. The ZrO2 samples containing only HA coatings, were also tested, for comparison. The obtained ceramic biomaterials were subjected to in vitro tests in the simulated body fluid (SBF) solution. The results show that the ZrO2 foams with FA/HA layers possessed better bioactivity than the foams with the HA/HA coating.
EN
The paper presents the main results of development and optimization of the synthesis of hydroxyapatite and the application of the micro-plasma spraying technique for biocompatible coatings. The hydroxyapatite synthesis was optimized using the mathematical modelling method. Synthesized hydroxyapatite was studied by IR spectrometry and X-ray diffraction analysis for assessment of the compatibility of the chemical and phase composition to the bone tissue. The Ca/P ratio of the obtained hydroxyapatite was 1.65, which is close to that of bone tissue (1.67). To increase the adhesion strength of the HA coating to the surface of the titanium implant, it was suggested to apply a titanium sublayer to the implant surface. Microplasma spraying (MPS) of biocompatible coatings from titanium wires and synthesized HA powders onto substrates made of medical titanium alloy has been carried out. Microplasmatron MPN-004 is used to obtain the two-layer coatings for titanium implants. The two layer coating includes a sub-layer of a porous titanium coating with a thickness in range from 200 up to 300 μm and the porosity level of about 30%, and an upper layer of HA about 100 μm thick with 95% level of HA phases and 93% level of crystallinity. The pore size varies from 20 to 100 μm in both coatings. The paper describes the technology and modes of microplasma deposition of two-layer coatings, including the mode of gas-abrasive treatment of the surface of implants made of titanium alloy before spraying. The synthesized HA powder and the Ti/HA coatings were investigated by optical microscopy and scanning electron microscopy with the energy dispersion analysis and the X-ray diffraction analysis.
EN
Hemagglutinin (HA) is a surface glycoprotein found in influenza viruses. This particle plays two crucial functions in the viral life cycle: it allows for the attachment of the virus into the host cell and participates in the fusion of the virus and host membranes. There are 18 different subtypes of HA. Recently, the H17 and H18 strains have been discovered whose hosts were bats. The evolution of these two strains had most likely occurred in isolation for a long period of time. This work presents the phylogenetic analysis and study on mutational variability based on sequences from all 18 currently known HA strains belonging to influenza virus type A. The results have been presented regarding the current knowledge about influenza. The classical software (Clustal, PHYLIP, and ConSurf) as well as original applications (SSSSg and Consensus Constructor) have been used in this research.
EN
A biocompatible hydroxyapatite (HA) coating with a thickness of about 18–20 microns was successfully deposited by radiofrequency (RF) magnetron sputtering on titanium substrates VT1-0. The data obtained for the optimal composition and structure of hydroxyapatite can be used to create coating which will interact with a titanium substrate. Using the methods of optical and SEM, AFM, electron microprobe, FTIR and X-ray analysis, surface morphology, phase and elemental composition, structure of hydroxyapatite (HA) coatings were studied. Structural and phase transformations after heat treatment using X-ray diffraction and microscopic methods of analysis were studied. It was found that after annealing coating phase analysis showed the presence of not only hydroxyapatite (Ca5(PO4)3OH), but also compounds of tricalcium phosphate (Ca3(PO4)2) and titanium oxide. Adhesivetribological durability, friction and deformation characteristics of hydroxyapatite coating on titanium substrate were determined. The obtained coatings had high hardness, wear resistance and adhesion to the substrate and low modulus of elasticity and coefficient of friction.
5
Content available remote Klastry pracy awaryjnej w środowisku Microsoft Windows Server 2012
PL
W artykule poruszono temat klastrów pracy awaryjnej w środowisku Microsoft Windows Server 2012. Klastry tego typu działają w oparciu o tzw. elementy quorum (kworum). W Windows Server elementem quorum może zostać węzeł, dysk „świadek” lub plik współdzielony „świadek”. Głównym celem artykułu jest porównanie czasów niedostępności usług świadczonych przez wymienione modele klastrów, w przypadku awarii elementów klastra, świadczących wybrane usługi. Analizie poddano architektury: Node Majority (elementy kworum w postaci węzłów klastra), Node and Disk Majority (elementy kworum w postaci węzłów klastra oraz dysku „świadka”), Node and File Share Majority (elementy kworum w postaci węzłów klastra oraz współdzielonego zasobu) oraz No Majority: Disk Only (element kworum w postaci dysku „świadka”).
EN
The article is all about failover clusters in Microsoft Windows Server 2012. Failover clusters called as well High-Availability Clusters creates a group of servers working together to provide high availability of provided by the cluster services and applications. Client devices see the cluster as a single system. Clusters of this type - in the family of Microsoft Windows Server - are based on element quorum. Quorum in failover clusters is considered as a parts of cluster witch has to be active to allow the cluster to work. Thanks to this each individual node of the cluster can check - by the single query - if the whole cluster can be active. In the MS Windows Server Environment component of a quorum may be for example: node, disk quorum, shared file quorum. The clusters models discussed in the article - provided by MS Windows Server 2012 - include: Node Majority, Node and Disk Majority, Node and File Share Majority and No Majority: Disk Only. The main purpose of the article is to compare the unavailability time of the services provided by these models of clustering in the case of cluster component failure.
6
Content available remote Wykorzystanie procesów biotechnologicznych do wytwarzania kwasu hialuronowego
PL
Tradycyjnym źródłem pozyskiwania kwasu hialuronowego (HA) są tkanki zwierzęce, m.in. grzebienie kogucie, gałki oczne i pępowina bydlęca. Jednak ze względu na limitowaną ilość surowca i ograniczenia spowodowane ryzykiem wirusowych zakażeń tkanek zwierzęcych oraz wysokie koszty procesów ekstrakcji, obecnie HA produkuje się z wykorzystaniem mikroorganizmów, takich jak bakterie z rodzaju Streptococcus sp. Trwają badania nad zastosowaniem rekombinowanych mikroorganizmów zdolnych do biosyntezy HA. W tym celu prowadzone są hodowle z udziałem modyfikowanych szczepów bakterii (Bacillus sp., Lactococcus lactis, Agrobacterium sp. i Escherichia coli) jako potencjalnych producentów pożądanego biopolimeru.
EN
A review, with 35 refs., of methods for microbial prodn.
7
Content available remote Kwas hialuronowy : budowa, właściwości i zastosowanie
PL
Kwas hialuronowy (HA) jest polisacharydem zbudowanym z powtarzających się jednostek disacharydów. W skład jednostki disacharydu wchodzi kwas D-glukuronowy i N-acetyloglukozamina połączone na przemian wiązaniami β-1,3- i β-1,4-glikozydowymi. HA występuje jako biopolimer o zróżnicowanej masie cząsteczkowej. W zależności od miejsca występowania i funkcji biologicznych wielkość cząsteczki mieści się w zakresie 104–107 Da. W organizmie ludzkim HA występuje w postaci soli sodowej, głównie w skórze, w ciałku szklistym oka oraz w pępowinie ludzkiej. Takie cechy HA, jak higroskopijność, biokompatybilność, elastyczność i sprężystość zapewniają mu szeroki zakres zastosowania w przemyśle kosmetycznym, biomedycznym oraz żywnościowym.
EN
A review, with 30 refs., of uses in cosmetics and medicine.
EN
The introduction of different bioelements into the structure of hydroxyapatite exerts a positive influence on the growth of new bone tissue. One such useful bioelement is silica, which possesses antibacterial properties and also acts as a factor regulating bone mineralization through stimulation of DNA to synthesize osteoblasts. Results of investigations into integration of foam titanium implants (FTI), with rabbit bone are presented. Two groups of implants were investigated: clean titanium implants produced by selective laser melting and FTI coated with a thin film of hydroxyapatite (HA) mixed with 10 wt. % of bioglass (BG) of A2 type (CaO- P2P-SiO2). Analysis of histopathology of implants' integration with bone were performed by staining using the triple chromatographic method of Masson - Goldner, planimetric analysis using the Kruskal - Wallis test, an ANOVA test and microtomography. Application of layers of the type HA+GH showed superior integration with bone than uncoated titanium implants.
EN
Results of investigations into integration of foam titanium implants (FTI), with rabbit bone are presented. Three groups of implants were examined: clean titanium implants produced by selective laser melting, FTI coated with a thin film of octacalcium phosphate (OCP), doped with 0.6 weight percent of Mg, deposited by pulsed laser deposition (PLD), and FTI with hydroxyapatite (HA) doped with 0.6 wt.% of Mg. Analysis of histopathology of implants' integration with bone were performed by staining using the triple chromatographic method of Masson - Goldner, pla- nimetric analysis using the Kruskal - Wallis test, an ANOVA test and microtomography. The best results were obtained for implants coated with HA, followed by those coated with OCP. Implants from these two groups showed superior integration with bone than uncoated titanium implants.
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