Library

feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
Filter
  • 1995-1999  (3)
  • 1990-1994  (5)
Material
Years
Year
  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Journal of materials science 6 (1995), S. 113-119 
    ISSN: 1573-4838
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine , Technology
    Notes: Titanium (Ti) has been used for many biomedical applications. Surface characteristics of titanium devices are critical to their success. In this study, Raman spectroscopy and X-ray photoelectron spectroscopy (XPS) were used to analyse Ti surfaces prior to immersion in alpha-modification of Eagle's medium (α-MEM). The ionic constituents deposited onto Ti surfaces after in vitro exposure to α-MEM were investigated using XPS and Fourier transform infrared spectroscopy (FTIR). Surface studies revealed an amorphous oxide layer on the Ti surface, with a chemistry similar to TiO2. However, after exposure to the physiologic solution for 12 days, dynamic changes in surface chemistry were observed. Ions such as phosphorus (P) and calcium (Ca) were increasingly deposited as amorphous fine crystalline calcium-phosphate (Ca−P) compounds, having a Ca/P ratio of 1.2 and a chemistry similar to brushite.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 2
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 49 (1993), S. 925-934 
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: A method has been developed for measuring infrared spectra during the mechanical deformation of yarns. This rheooptical technique was applied to study the molecular processes that take place along the stress-strain curve of PET yarns. The results were combined with data obtained from size exclusion chromatography (SEC) and tensile measurements at elevated temperatures. The results indicate that the first modulus maximum marks the breakdown of the amorphous entanglement network and the start of molecular uncolling by gauche → trans transitions. In addition, stress develops on the crystals and particularly on tie molecules with a short contour length in the amorphous domains. Ultimately, molecular fracture of taut-tie molecules causes the modulus to pass through a second maximum. The chain ends of broken molecules recoil by trans → gauche transitions. Local stress accumulation will lead eventually to yarn rupture. © 1993 John Wiley & Sons, Inc.
    Additional Material: 12 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 3
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Biomaterials 5 (1994), S. 203-213 
    ISSN: 1045-4861
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine , Technology
    Notes: In this study, the corrosion and surface properties of four commercially available nickel-chromium dental casting alloys, were evaluated using electrochemical corrosion testing and Auger electron microscopy. The corrosion tests were conducted under cell culture conditions of 5% CO2 humidified atmosphere at 37°C in minimum essential medium (MEM) balanced salt solution, 95% MEM-5% FBS (fetal bovine serum) cell culture media, and in 95% MEM-5% FBS media after cold solution sterilization of test samples. The results of the surface and corrosion analyses were correlated to cytotoxicity and metal ion release from the alloys using agarose overlay and direct contact cell culture tests. The surface and electrochemical corrosion analyses demonstrated that the non-beryllium containing alloys were more resistant to accelerated corrosion processes as compared to the beryllium-containing alloys. All alloys demonstrated decreased corrosion rates in cell culture solutions after cold solution sterilization treatment. The corrosion products released from the nickel-based alloys failed to alter the cellular morphology and viability of human gingival fibroblasts, however they did cause reductions in cellular proliferation. The potential for accelerated corrosion and the exposure of local and systemic tissues to elevated levels of corrosion products raises concerns over the biocompatibility of these alloys. © 1994 John Wiley & Sons, Inc.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 4
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 45 (1992), S. 1649-1660 
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The results of a study of the relation between a number of mechanical properties of poly(ethylene terephthalate) (PET) yarns and their physical structure are presented. The relation was studied on a set of 295 drawn yarn samples, resulting from an exceptionally large variety in process conditions applied. The size of this experiment offered a unique opportunity to study the property-structure relation more extensively than ever before. Therefore, our understanding of the mechanical properties could be enriched with several new insights. A selection of seven yarn properties has been investigated. Five of them have been derived from the stress-strain curves and the remaining two are shrinkage and shrinkage force. The physical structure has been described with a set of five, statistically selected, parameters. Most of the yarn properties could very well be described in terms of these structure parameters. This description was performed by means of an artificial neural network, ANN. The type of calculation is completely naive, i.e., without any specific mathematical formulation for the relation concerned. The fitting results have been translated into physical aspects related to the well-known molecular two-phase model. The practical importance of a good physical understanding of yarn properties is that the essential possibilities and impossibilities of combinations of properties can far more easily be surveyed and understood. As a result, the efficiency of process developments can be substantially improved.
    Additional Material: 15 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 5
    Electronic Resource
    Electronic Resource
    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 27 (1993), S. 1501-1507 
    ISSN: 0021-9304
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine , Technology
    Notes: Plasma sprayed hydroxylapatite (HA) coatings on titanium substrates were analyzed for process-induced compositional and structural changes. The HA starting powder and the resulting HA coatings were characterized using x-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and Raman spectroscopy. The integrity of the ceramic-to-substrate bond strength was also determined, by subjecting plasma sprayed HA coatings to shear/cantilever bond testing. The ceramic coatings retained the basic apatitic crystal structure of the starting powder; however, a considerable amount of amorphous material was created during the plasma spray process. FTIR and Raman spectroscopy revealed that the resulting coatings were partially dehydroxylated. Both XRD and FTIR spectroscopy results also suggested that amorphous material, as well as additional calcium phosphate phases such as α-tricalcium phosphate (TCP) not in the starting powder, were present in the HA coating. Average bond strengths of the HA coatings to Ti were determined to be 14.8 MPa +/- 3.5, with fracture occurring at the interface and within the coating itself. © 1993 John Wiley & Sons, Inc.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 6
    Electronic Resource
    Electronic Resource
    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 29 (1995), S. 611-617 
    ISSN: 0021-9304
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine , Technology
    Notes: Previous cell culture evaluations have shown that nickel-chromium dental alloys did not affect cellular viability or morphology. However, nickel-based alloys released corrosion products which decreased cellular proliferation. It was hypothesized that this decrease was due to an interference of cellular energy metabolism by released metal ions. To test this hypothesis, we evaluated the effects on cellular energy metabolism, adenosine triphosphate (ATP) levels, and cellular ultrastructure by four nickel-based alloys, including high and low chromium alloys with and without beryllium additions, in human gingival fibroblast cell culture. Energy metabolism was evaluated by measuring glucose-6-phosphate dehydrogenase (G-6-PDH) activity. ATP levels were measured with the luciferin-luciferase method. Cellular membranes and ultrastructural organization were evaluated by scanning and transmission electron microscopy. The results of this study showed that metal ions released from all alloys completely inhibited G-6-PDH activity and reduced cellular ATP levels as compared to controls. The reduction in intracellular ATP was greater for the beryllium containing alloys than the non-beryllium-containing alloys. However, no morphologic changes in cellular membranes or organelles were observed. These results support the hypothesis that metal ions released from nickel-based dental casting alloys interfere with cellular energy metabolism. © 1995 John Wiley & Sons, Inc.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 7
    Electronic Resource
    Electronic Resource
    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 28 (1994), S. 1337-1346 
    ISSN: 0021-9304
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine , Technology
    Notes: The surfaces of bioactive Ca-P ceramics immediately change when exposed to proteinaceous solutions. The dissolution behavior and protein interactions of these bioactive materials at the bone/implant interface need to be investigated to understand their material-cellular interactions fully. In this study, FT-IR/ATR techniques were used to study the in situ phosphate release kinetics of Ca-P coatings. The net loss of phosphate molecules from coatings was slower in saline solutions compared with α-MEM solutions. Coatings exposed to α-MEM solutions containing fibronectin released phosphate molecules slower than coatings exposed to α-MEM solutions containing albumin. Conformational changes in fibronectin and albumin adsorbed onto Ca-P and uncoated germanium surfaces were also investigated using FT-IR/ATR spectroscopy. Analysis of changes in the amide I bands indicated that there was a greater loss of β-sheet structure in adsorbed fibronectin on Ca-P coatings when compared with bare germanium surfaces. Although albumin did change its structure upon adsorption on both Ca-P and germanium, unlike fibronectin, adsorbed albumin structure was similar on Ca-P coatings and germanium. Furthermore, with time the conformation of adsorbed fibronectin and albumin appeared to be very stable on Ca-P coatings, whereas albumin adsorbed to germanium exhibited an increase in ratio of α-helix to βturn. © 1994 John Wiley & Sons, Inc.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 8
    Electronic Resource
    Electronic Resource
    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 29 (1995), S. 165-172 
    ISSN: 0021-9304
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine , Technology
    Notes: The cellular response to well-characterized Ca-P and Ti surfaces was analyzed. This study indicated that the ion-beam sputtering process could produce a hydroxyapatite-type coating. However, structural alterations such as the incorporation of CO3 and the loss of the OH groups were observed. The Ti surfaces were shown to be predominantly amorphous TiO2. The in vitro cell culture study showed no significant differences in cell number for the Ti and Ca-P surfaces throughout the 12-day study. Furthermore, the initial percentage of protein within the cell layers was significantly lower for cells on Ca-P surfaces compared with the cell layer on Ti surfaces. However, after 3 h incubation, no significant difference in the percentage of protein was observed for the Ti and Ca-P surfaces. © 1995 John Wiley & Sons, Inc.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...