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  • 1
    Electronic Resource
    Electronic Resource
    s.l. ; Stafa-Zurich, Switzerland
    Key engineering materials Vol. 288-289 (June 2005), p. 47-50 
    ISSN: 1013-9826
    Source: Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: In order to improve the tissue integration and subsequently the long-term maintenance, the implant surface can be modified by mechanical, physical, chemical or biological functionalization. In this way, the surface becomes biologically active by further grafting of biomolecules. Two principal concepts are considered for materials functionalization. (i) The Drug Delivery Systems (DDS) where the bioactive molecules goes to the target. (ii) The grafting of the bioactive compounds onsmall strongly bound spacer molecules. In this system, the target goes to the bioactive molecules. These techniques provide promising outlooks for any polymeric or ceramic scaffold used in tissue engineering for the construction of whole artificial and functional organs
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1013-9826
    Source: Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: LASER Excimer irradiation can modify surface properties for biocompatibility improvement of a medical device. The PETs from 3 different origins were used in this study. The samples have been irradiated by excimer LASER with 10 different energies. The surface profile, the surface energy and the materials crystallinity have been assessed. Biological characterizations were made with human embryonic epithelial cells L132: proliferation, vitality, viability, adhesion with the p-NPP, and morphology. - The profile measurements allowed to establish the ablation threshold, which was 36 mJ/cm². The surface hydrophilic state increased reciprocally with the irradiation intensity. The gain is 13 %. The irradiated and non-irradiated product has identical cristallinity. PET was shown not to be toxic for L132 cells. Cell proliferation and cell vitality showed dose-dependant increases reciprocal to the irradiation energy (from 88 to 138% with respect to control). The correlation was highly significant (R² = 0,8). SEM micrographs show that the cells are better spread on the surface of irradiated PET than on untreated PET
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    s.l. ; Stafa-Zurich, Switzerland
    Key engineering materials Vol. 288-289 (June 2005), p. 633-636 
    ISSN: 1013-9826
    Source: Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: PE is manufactured by Transysteme with the method of thermocompression of PE powder. This company irradiates PE by YAG LASER. We compared the physical behavior of both samples. The DSC reveals a high and similar crystallinity of PE, before and after YAG LASER treatment. Weattability between PE and Li-PE are similar at about 37 mJ/cm². The difference appears with respect to the surface profile and composition: the roughness is 0.20 µm for PE and 0.29µm for Li- PE. XPS reveals many traces of stripping agents on PE. YAG Laser produces a surface cleaning effect. Biological tests reveal a non-toxicity of the polyethylene powder, an improved proliferation and vitality of L132 cells on Li-PE with respect to untreated PE. We have a 4-fold improvement of proliferation and a 2-fold improvement of vitality on Li-PE with respect to PE. As to morphology and cell adhesion behavior, we have no differences between both samples. Thus the irradiation process of PE by YAG LASER improved the biological behaviors of this polymer due to changes in roughness and to surface cleaning
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Springer
    Research in experimental medicine 162 (1974), S. 109-124 
    ISSN: 1433-8580
    Keywords: Parenteral nutrition ; Amino acid solutions ; Plasma amino acids ; Parenterale Ernährung ; Aminosäure ; Infusionslösungen ; Aminosäuremuster im Plasma
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung 1. Bei gesunden Versuchspersonen, die mit einer calorisch ausreichenden stickstofffreien Diät ernährt wurden, wurden 3 verschiedene Aminosäurelösungen als einzige Stickstoffquelle parenteral zugeführt. Am 3. Infusionstag wurde die Konzentration der freien Aminosäuren im Plasma vor, während und am Ende der Infusion sowie 30, 60 und 180 min nach dem Absetzen bestimmt. Die Nüchternwerte wurden am 1., 3. und 5. Infusionstag bestimmt und miteinander verglichen. Am 3. Infusionstag wurde außerdem die Ausscheidung der verschiedenen Aminosäuren im Harn gemessen. 2. Während und nach der Infusion ergaben sich starke Veränderungen in der Konzentration der meisten Aminosäuren im Plasma. Dadurch wurde die physiologische Relation der einzelnen Plasmaaminosäuren mehr oder weniger verschoben. Die langfristige Verabreichung der Infusionslösungen führte zu Verschiebungen auch der Nüchternwerte und zu einem Anstieg des Gesamtaminostickstoffs im Plasma. 3. Die Unterschiede zwischen dem Verhalten der Plasmaaminosäuren nach den verschiedenen Infusionslösungen lassen sich mit der durch Stickstoffbilanzuntersuchungen an den gleichen Versuchspersonen gesicherten unterschiedlich guten biologischen Wertigkeit der Lösungen korrelieren. Die Lösung, die die beste Stickstoffbilanz ergeben hatte, bewirkte auch die geringsten Veränderungen im Aminosäurespektrum des Plasmas.
    Notes: Summary Three different amino acid solutions as only source of nitrogen were infused in healthy volunteers taking a nitrogen-free high-caloric diet orally. On the 3rd day of parenteral nutrition the concentration of the free plasma amino acids were determined before, during, on termination, and 30, 60 and 180 min after the infusion. The fasting levels were determined on the 1st, 3rd and 5th day of infusion. The urinary amino acid excretion was measured on the 3rd day. During and after the infusion significant alterations in the concentration of most amino acids were observed. The physiological pattern of plasma amino acids was altered temporarily. The long-term administration of plasma amino acid solutions altered the fasting levels somewhat and increased the total amino nitrogen in the plasma. The different effect of the three solutions on amino acid levels in plasma was correlated to differences in the biological value of these solutions as observed in nitrogen balance studies in the same subjects. The amino acid solution with the best results in nitrogen balance studies lead to the smallest changes in the pattern of plasma amino acids.
    Type of Medium: Electronic Resource
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