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  • 1
    Digitale Medien
    Digitale Medien
    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 1 (1967), S. 1-2 
    ISSN: 0021-9304
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Medizin , Technik allgemein
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 2
    Digitale Medien
    Digitale Medien
    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 1 (1967) 
    ISSN: 0021-9304
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Medizin , Technik allgemein
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 3
    Digitale Medien
    Digitale Medien
    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 1 (1967), S. 11-16 
    ISSN: 0021-9304
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Medizin , Technik allgemein
    Notizen: Methyl α-cyanoacrylate, when implanted subcutaneously in rats and dogs, has been shown to lead to an increase in thiocyanate output in the urine, presumably through the formation of cyanide anions which are subsequently converted to thiocyanate. It is postulated that this reaction may be one of the reactions contributing to tissue necrosis when methyl α-cyanoacrylate is used as a tissue adhesive.
    Zusätzliches Material: 3 Ill.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 4
    Digitale Medien
    Digitale Medien
    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 1 (1967), S. 3-9 
    ISSN: 0021-9304
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Medizin , Technik allgemein
    Notizen: In an effort to obtain tissue adhesive monomers which would wet and spread on tissue substrates and be rapidly biodegradable, the branched esters of alkyl α-cyanoacrylates, as well as a 95-5 wt.-% mixture of n-heptyl and methyl α-cyanoacrylate, were studied. The data indicate that alkyl α-cyanoacrylates having branched alkoxy groups appear to be promising in this regard.
    Zusätzliches Material: 4 Ill.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 5
    Digitale Medien
    Digitale Medien
    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 1 (1967), S. 27-31 
    ISSN: 0021-9304
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Medizin , Technik allgemein
    Notizen: A theory for the behavior of anodes as stimulus electrodes, particularly as pacemaker electrodes, is presented. Expressions are obtained for the minimum duration and energy of the stimulus. These expressions are applied to that for the dissolution of the anode and transport of the resulting ions in the tissue in order to obtain an estimate of the extent of penetration. Comparison with experimental data indicates good agreement.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 6
    ISSN: 0021-9304
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Medizin , Technik allgemein
    Notizen: New dialysis membranes, prepared from linear block copolymers, have shown unique separation properties which appear to be based on definite solute-membrane interaction. The synthesis and characterization of block copolyetherurethanes based on poly (oxyethylene glycol) is described.
    Zusätzliches Material: 1 Ill.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 7
    Digitale Medien
    Digitale Medien
    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 1 (1967), S. 33-54 
    ISSN: 0021-9304
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Medizin , Technik allgemein
    Notizen: Currently available materials for mechanical heart systems are surveyed, particularly with respect to long-term implantation, from the viewpoints of availability and workability, mechanical and biological durability, and compatibility with blood and tissue. Some materials have one or more desirable physical properties, but none offers perfect blood and tissue compatibility. Medical grade Silastic, considered best for blood handling parts, has produced promising results in auxiliary ventricle patency experiments. The insufficient tensile strength of Silastic should be increased, and it may be possible to accomplish this while maintaining the present resilience, elongation, and inertness. No long-term data on thrombus formation are available, but clot-retarding quality is essential and may perhaps be obtained by incorporating heparin. Developments in polymer chemistry may also lead to other surfaces with the requisite mechanical properties with blood.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 8
    ISSN: 0021-9304
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Medizin , Technik allgemein
    Notizen: Seven surgical adhesives were prepared; n-butyl, 2-ethylhexyl, and isopropyl cyanoacrylate monomers and several combinations of ethyl cyanoacrylate and a plasticizer (either di-2-ethylhexyl phthalate or tricresyl phosphate). These were implanted as a thin film over the entire circumference of the adventitia of 48 canine carotid arteries. Vicissitude of cyanoacrylate polymers in vivo and tissue reaction to the polymers were traced for 6 months and investigated histologically. All adhesives tested in this study were insoluble in vivo and more resistant to biodegradation than methyl cyanoacrylate polymer. Tissue reaction against n-butyl, 2-ethylhexyl, or isopropyl cyanoacrylate was essentially the same as against ethyl cyanoacrylate in quality and was not less in degree than ethyl cyanoacrylate in spite of having longer side chains than ethyl radical.
    Zusätzliches Material: 5 Ill.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 9
    ISSN: 0021-9304
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Medizin , Technik allgemein
    Notizen: Evidence is presented for the view that intravascular thrombosis proceeds via an electrochemical mechanism. It is strongly substantiated by some recent work on electrical wire thrombosis. These experiments show that thrombosis occurs on noble metal electrodes at potentials more positive than 0.3 v (NHE) but tends not to occur on electrodes more negative than this interfacial potential. Further, the same factors which prevent intravascular thrombosis are shown to prevent thrombosis on electrodes maintained at all potentials up to + 1.0v. Thus occurrence or prevention of thrombosis appears related to electrical and electrochemical properties of both blood and blood vessel wall. Methods for the determination of these properties are described and experimental results briefly presented. The studies have proved useful in establishing criteria for the selection of metal and plastic vascular substitutes. A combination of several electrochemical and biophysical criteria have been discovered which aid in the selection of nonthrombogenic vascular substitutes. Unfortunately not all metals which satisfy anti-thrombotic electrochemical criteria are suitable. Many, including magnesium, have cellular and proteolytic destructive characteristics. Certain metals and electrically treated Teflon tubes do not suffer from this defect and have proven useful in preliminary testing.
    Zusätzliches Material: 10 Ill.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 10
    ISSN: 0021-9304
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Medizin , Technik allgemein
    Notizen: A major part of current effort in improving artificial hemodialysis techniques concerns the development of improved membrane structures. Although blood compatibility of membranes is a part of the Battelle program, this discussion is confined to membrane composition, structure, and transport. On the basis of a need for improved hemodialysis techniques, membranes for use in the artificial kidney were prepared and evaluated for urea, creatinine, and uric acid permeability. Water-soluble polymers were crosslinked to form insoluble, but swellable, membranes. Faster metabolic waste transfer than with the conventional cellulosic membranes was obtained with diisocyanate-crosslinked poly (vinyl pyrrolidone) and poly (vinyl pyrrolidone)-dextran membranes and with membranes obtained by crosslinking poly (vinyl alcohol) with polyfunctional aldehydes. Membranes prepared from emulsions of vinyl pyrrolidone-ethyl acrylate and vinyl pyrrolidone-styrene copolymers had exceptionally high urea and creatinine dialysis rates, but were deficient in uric acid transfer. This shortcoming was corrected by incorporating solutes such as sucrose into the membranes followed by leaching. Another important approach concerned the development of a relatively high-strength membrane based on an impermeable nylon resin. Permeability of these membranes which have dialysis characteristics superior to those currently used was obtained through the addition of DMSO and one of several other additives to the coating solution.
    Zusätzliches Material: 1 Ill.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 11
    ISSN: 0021-9304
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Medizin , Technik allgemein
    Notizen: The tissue reaction to metallic and nonmetallic implants in the back muscles of New Zealand White Rabbits is presented. These reactions are graded and correlated with the trace metal contained around such implanes. Correlations are drawn as to the acceptability of various materials for the manufacture of surgical implants.
    Zusätzliches Material: 18 Ill.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 12
    Digitale Medien
    Digitale Medien
    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 1 (1967), S. 103-112 
    ISSN: 0021-9304
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Medizin , Technik allgemein
    Notizen: The pressure losses in the currently available prostheses are too high. We believe an excellent way to focus designers' attention upon this fact is to rank the various designs according to their hydraulic efficiency. The proposal of this paper is for pressure drop vs. velocity data (pulsatile flow) to be taken similar to that of Figure 2, so that a pressure loss coefficient, Kv, based upon the valve lumen area can be found for each valve design; further, that this Kv be used to compare and rank the various valve designs. The fact that Kv is a dynamic loss coefficient guides designers toward its improvement, for this compares the prosthesis problem to many “solved” problems (propeller blade profiles, hydrofoil profiles, etc.) which are similar hydraulically. The confusion of the surgeon when confronted with conflicting claims regarding various prostheses would be largely eliminated by acceptance of Kv as a figure of hydraulic merit by those concerned with this aspect of biomedical engineering.
    Zusätzliches Material: 6 Ill.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 13
    Digitale Medien
    Digitale Medien
    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 1 (1967), S. 171-174 
    ISSN: 0021-9304
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Medizin , Technik allgemein
    Notizen: The problems with the experimental and clinical assessment of arterial prosthetic materals vary from species-transfer of data to vested interests once an implantale device has been perfected for human trail. In spite of all the problems which arise, there has been a steady increase in our knowledge of the basic healing pattern of implanted arterial prostheses and the elaboration of specific paths for improvement of prosthetic design. Further development will be linked closely to the active participation of the biomedical researcher in areas of biophysical and bioengineering investigations.
    Materialart: Digitale Medien
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  • 14
    Digitale Medien
    Digitale Medien
    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 1 (1967), S. 113-134 
    ISSN: 0021-9304
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Medizin , Technik allgemein
    Notizen: Semicrystalline polymers used as restorative prostheses in the cardiovascular system require more detailed consideration of flexural fatiguing with simple physical characterization and mechanical measurements as one basic means for developing test standards and specification levels for biomedical research materials. Such initial means are considered with polytetrafluoroethylene as a reference polymer nominally inert chemically used to illustrate one approach to assessing morphological and structural changes with a flex tester. Density measurements and void content have been carried out to provide one means of assessment whereby the corresponding crystallinity and permeation can be considered for more detailed correlation to cytological interactions as the polymers are used as replacement components in the cardiovascular system. Progressive flexural cycling up to 106 cycles at a 3 cps rate indicate significant decreases in crystallinity simultaneously with increasing void content. As an accelerated test, the implications for extrapolation to 25-year fatiguing in normal physiological cycling rate are conjectured to provide a starting point for more realistic, cyclic ex vivo screening of biomaterials.
    Zusätzliches Material: 6 Ill.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 15
    Digitale Medien
    Digitale Medien
    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 1 (1967), S. 175-175 
    ISSN: 0021-9304
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Medizin , Technik allgemein
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 16
    Digitale Medien
    Digitale Medien
    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 1 (1967), S. 175-175 
    ISSN: 0021-9304
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Medizin , Technik allgemein
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 17
    Digitale Medien
    Digitale Medien
    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 1 (1967) 
    ISSN: 0021-9304
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Medizin , Technik allgemein
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 18
    Digitale Medien
    Digitale Medien
    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 1 (1967), S. 176-176 
    ISSN: 0021-9304
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Medizin , Technik allgemein
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 19
    ISSN: 0021-9304
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Medizin , Technik allgemein
    Notizen: The clotting problem inside the artificial heart device is one of the major obstacles standing in the way of a successful long-term implantation of the artificial heart. To date, there have been two artificial heart devices used clinically. One is the auxiliary ventricle and the other is the left heart bypass pump. The former is for permanent implantation and the other is implanted only temporarily. Several experimental results which had contributed to the successful implantation of the auxiliary ventricle are described, especially from the standpoint of avoiding the clotting inside the device. Basic experiments with the left heart bypass pump are also described. The valves are the foremost problem and the next is the junction of the two materials. It is ideal to have a smooth, seamless surface made entirely of one material. It is also necessary to have a flow pattern analysis inside the artificial heart device as well as a clotting pattern analysis. Since the pump oxygenator and heparinization are involved in the procedure, the clotting problems in the total heart experiment are usually less than in the left heart bypass experiments. Our most urgent requirement is the development of new antithrombogenic material. However, even with our present material a large part of the clotting could be avoided if the heart is carefully constructed.
    Zusätzliches Material: 12 Ill.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 20
    Digitale Medien
    Digitale Medien
    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 1 (1967), S. 179-196 
    ISSN: 0021-9304
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Medizin , Technik allgemein
    Notizen: Warp-knitted velour fabrics of Dacron, nylon, polypropylene, and Rayon have been backed with Silastic to form a laminate. Prior to heat curing, the composite can be molded into many shapes and has been successfully used to line the luminal side of blood pumps and vascular grafts. Prosthetic heart valves are being covered with velour in an attempt to promote a more compatible surface. Velour suture rings are being evaluated as a more efficient anchor for prosthetic heart valves. Silastic tubes with velour bonded to the outer wall have been used to inhibit infection and sinus tract formation where percutaneous lead wires and conduits are necessary. As a flat sheet, the Silastic-velour laminate has been used experimentally as an artificial skin, but the most noteworthy experimental results have been obtained in rats using a double layer of nylon velour, separated by an impermeable layer of poly(vinyl fluoride). Future application will include attempts to anchor artificial limbs via a velour interface and made functional by tendinous attachment.
    Zusätzliches Material: 16 Ill.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 21
    ISSN: 0021-9304
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Medizin , Technik allgemein
    Notizen: Inhibition of cultured mammalian cell growth was used to examine the biological activity of triethyl citrate, a common plasticizer for poly(vinyl chloride). Cell populations were determined by a sample extraction procedure and measurement of nucleic acid content (total purines and pyrimidines) by its absorbance at 268 mm̈. Triethyl citrate demonstrated strikingly different dose-effect characteristics from its theoretical hydrolysis products (ethanol and citric acid). The inhibitory effects of sodium citrate were reversed by calcium chloride while the action of triethyl citrate underwent little or no change under similar conditions. Triethyl citrate did not appear to produce resistant cell strains in culture but did seem to be degraded with time. Inhibitory action of triethyl citrate was shown to be independent of inoculum size within the ranges utilized in the study. The procedures described appear to have a number of advantages for the biological or toxicological evaluation of ingredients which might be added to a plastic formulation or to contaminates which might enter the plastic during manufacture of the item or device.
    Zusätzliches Material: 8 Ill.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 22
    ISSN: 0021-9304
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Medizin , Technik allgemein
    Notizen: A series of studies were performed using S35-labeled heparin to determine the amount and the permanancy of heparin grafted onto nonthrombogenic surfaces. The calculated thicknesses of the heparin layers (based on geometrical areas) ranged from 100 to 1500 A. It was shown that the surface having a 100-A layer of attached heparin was nonthrombogenic. The stability of the heparin attached to polypropylene, silicone rubber, hydrin rubber, and graphite-benzalkonium-heparin (GBH) surfaces in distilled water, isotonic saline, and human plasma was measured. The results showed that after exposure to water and saline, the first three surfaces retained most of the attached heparin (〉90%) in contrast to the GBH surface which retained only 31%. After contact with human plasma for 3 hr at 37°C, polypropylene retained 32% and GBH surfaces 19% of the heparin which was initially present. In another series of experiments, the adsorption of P32-labeled proteins onto unheparinized, quaternary ammonium, and heparinized surfaces was measured. The results indicated that the amounts of albumin, Hageman factor, thrombin, and γ-globulin adsorbed onto heparinized surfaces were equal to or greater than the amounts adsorbed onto unheparinized surfaces. The implications of this in terms of the nonthrombogenicity of the heparinized surfaces are discussed.
    Zusätzliches Material: 7 Tab.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 23
    Digitale Medien
    Digitale Medien
    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 1 (1967), S. 213-238 
    ISSN: 0021-9304
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Medizin , Technik allgemein
    Notizen: 1. With the help of ionotropic gels it is possible to duplicate native structures consisting of two materials, one of them the matrix. 2. Counter-ions combined with the ionic groups on the ordered polyelectrolytes can be exchanged. With certain counter-ions an insoluble, crystalline precipitate is formed immediately after the ion-exchange process as an ordered reaction product, i.e., nucleation. 3. Ionotropic gels were crosslinked through the secondary hydroxyl groups (uronic acid residuals) in such a way that the rate of ion exchange was only slightly lower, that no great shrinkage resulted, and that the pores remained free of extraneous polymers. 4. The microscopic structure of ionotropic gels can be divided into (a) a part with secondary structure with micellar particles and hollow pores and (b) a part with tertiary structure with lamellae and isopores. 5. On crystallization in shrunken gels the crystals enter into the tertiary structure - both intracapillary as well as interlamellar - due to spatial reasons. 6. Through control of the shrinkage of the gels, one can regulate the way in which the ordered crystals enter into the two structures. 7. One can change the size of the crystallites by variation of the degree of crosslinking. The higher the degree of crosslinking, the smaller the crystallite. 8. By treatment with waves of ions one can increase the solid content of the gel to values from 50 to 70%. One obtains gels with a mechanical strength like that of bones, teeth, shells, or pearls. The phenomenon of intramicellar crystallization is reversible. Monovalent counter-ions, as well as H-ions, dissolve and extract the included secondary substance. One then obtains the original crosslinked gel. 10. The gel has always to be formed first. Without the ordered base structure (matrix) one obtains unordered crystallites such as occur in the chalklike fields of the pearl shells.
    Zusätzliches Material: 14 Ill.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 24
    Digitale Medien
    Digitale Medien
    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 1 (1967), S. 253-261 
    ISSN: 0021-9304
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Medizin , Technik allgemein
    Notizen: Porous laminates prepared by incorporating a volatile solvent into an epoxy resin system used to impregnate a fabric filler satisfactorily alleviated the problems caused by perspiration in upper extremity prostheses, but did not have sufficient strength for use in artificial legs. A new technique is described which results in a 100% increase in both porosity and strength of porous epoxy laminates. The method consists of impregnation of the fabric with resin and solvent and evaporation of the solvent prior to laying up the laminate. The improvement in properties is ascribed to better control and homogeneity of impregnation.
    Zusätzliches Material: 2 Ill.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 25
    Digitale Medien
    Digitale Medien
    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 1 (1967), S. 275-284 
    ISSN: 0021-9304
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Medizin , Technik allgemein
    Notizen: A design theory is developed for a compact artificial kidney utilizing microcapsules containing urease, ion exchange resin, and adsorbents for uric acid and creatinine. It is shown that the critical factor is the permeability property of the microcapsule wall and that an artificial kidney 10 cm in length and 2 cm in diameter is feasible.
    Zusätzliches Material: 6 Ill.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 26
    Digitale Medien
    Digitale Medien
    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 1 (1967), S. 285-297 
    ISSN: 0021-9304
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Medizin , Technik allgemein
    Notizen: Samples of (Ag + Hg) amalgam and of dental amalgam have been prepared and stored at temperatures of 23, 37.5, and 60°C for various lengths of time up to 10 years. X-ray diffraction and optical microscopy have been employed to determine the approximate increase in the β(Ag—Hg) phase as a result of the γ → β transition in the Ag—Hg system. Data are presented to show that the transition occurs in both systems but much less rapidly in dental amalgam. Increases in storage temperature increase the rate of the transition in both systems.
    Zusätzliches Material: 6 Ill.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 27
    ISSN: 0021-9304
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Medizin , Technik allgemein
    Notizen: Strains were determined in a typical mandibular partial denture metal framework of the free-end saddle type. The overall strain patterns were determined using a brittle lacquer coating technique and loads were applied vertically to positions on the saddles. The results from the coating study indicated the area of high strain were just anterior and posterior to the finishing lines. Strain gages were attached to positions anterior and posterior to the finishing lines and the strain was measured at these positions when the saddles were loaded either at a posterior or anterior position at intervals of 2 lb up to 20 lb. When a static load of 20 lb was applied to the posterior of the left saddle a strain of 750 μ in./in. was obtained, which for the alloy used was equivalent to a stress of 22,200 lb/in.2. The amount of strain observed was a function of the length of the saddle, the bulk of the framework, the relation of the site of the gage to the position of loading, the presence of an indirect retainer, and the position of the fulcrum for the loading conditions used.
    Zusätzliches Material: 10 Ill.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 28
    Digitale Medien
    Digitale Medien
    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 1 (1967), S. 299-299 
    ISSN: 0021-9304
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Medizin , Technik allgemein
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 29
    Digitale Medien
    Digitale Medien
    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 1 (1967) 
    ISSN: 0021-9304
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Medizin , Technik allgemein
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 30
    Digitale Medien
    Digitale Medien
    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 1 (1967), S. 301-312 
    ISSN: 0021-9304
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Medizin , Technik allgemein
    Notizen: The present paper describes a new technique for preparing the surface of polyethylene and polypropylene plastics for the adsorption of heparin. The procedure consists of exposing the plastic surface to a solution of cationic surfactants at a temperature close to the softening temperature of the plastic. The mechanism of adsorption of the anticoagulant of the surfaces is discussed.
    Zusätzliches Material: 5 Ill.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 31
    Digitale Medien
    Digitale Medien
    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 1 (1967), S. 325-336 
    ISSN: 0021-9304
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Medizin , Technik allgemein
    Notizen: In 14 canines the ureter was substituted with a new type of ureteral gel-fabric prosthesis. The prosthesis is a tube of knitted fabric of polyester fiber case in a layer of hydrophilous glycol methacrylate gel. Anastomoses were carried out by inserting the prosthesis ends into the ureter lumen and by suturing the stump of the ureter to a special fixing ring on the prosthesis. Preliminary results of short-term obsevations (4 months) are quite promising. The prosthesis is non-irritating and conducts the urine satisfactorily.
    Zusätzliches Material: 9 Ill.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 32
    Digitale Medien
    Digitale Medien
    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 1 (1967), S. 313-323 
    ISSN: 0021-9304
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Medizin , Technik allgemein
    Notizen: The biologic properties of the sponge-like polymers of ethylene glycol methacrylate gels and their host compatibility have been verified in subcutaneous and intraperitoneal application in rats. All three sample types tested, with different porosities, have been tolerated very well with the receptor and have caused no pathologic reaction. Subcutaneous implants are directly integrated in teh organism, cellular immigration taking place with vascularization of the surface layer of the implantate to a depth of some 500 μ during the second week after implantation, causing the sponge to become an integral component of the surrounding tissues. More substantial differences in the reaction to the presence of implantates of different porosity ahve not been observed. These properties directly predetermine the sponge-like polymers for wider application in plastic and reconstructive surgery. In addition, there is the possibility of utilizing them as an auxiliary surgical material, e.g., for drying and cleaning the operative field, or as operation towels. Good results have been achieved also in mechanically stopping bleeding from parenchymatose organs by application of the sponge foil.
    Zusätzliches Material: 8 Ill.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 33
    Digitale Medien
    Digitale Medien
    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 1 (1967), S. 337-354 
    ISSN: 0021-9304
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Medizin , Technik allgemein
    Notizen: Features controlling the initiation of matrix calcification have been investigated in a model system. Two major influences which dominate nucleation are the matrix integrity and the location of certain chemical binding sites. It has been shown that chemical chelating groups can, and do, promote calcification under simulated physiological conditions. Organically bound phosphate does not appear to promote nucleation, suggesting that it is chelation of calcium or other cations which is the initial step in tissue calcification. In the sequence of compounds investigated for nucleation catalysis, those possessing at least three chelating groups and a stereopsecific configuration were effective. The mineral phase forming first in association with the organic matrix is a soft non-apatitic calcium phosphate of Ca/P ratio approximately 1.5. This is the same phase that forms in the absence of organic matrices at physiological pH and is probably the precursor to hydroxyapatite in biological calcification. It is suggested that nucleation catalysts exist both within and outside the collagen fibrillar framework. A possible location of the internal site has been proposed, based on the availability of a capillary channel and chelating ligands, and this postulate is supported by electron microscopic evidence which shows that bone crystals lie within the fibrils, occupying space which terminates in the polar 640 A staining area.
    Zusätzliches Material: 4 Ill.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 34
    Digitale Medien
    Digitale Medien
    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 1 (1967), S. 369-369 
    ISSN: 0021-9304
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Medizin , Technik allgemein
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 35
    Digitale Medien
    Digitale Medien
    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 1 (1967) 
    ISSN: 0021-9304
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Medizin , Technik allgemein
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 36
    ISSN: 0021-9304
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Medizin , Technik allgemein
    Notizen: Knowledge of the characteristics of the blood-intima interface is important because it leads to information concerning (a) the normal antithrombotic mechanism (b) nature of interreactions between blood and intima (c) testing and selection of vascular wall substitutes which are antithrombotic and inhibit clotting. A technique for obtaining the electrical interfacial characteristics of blood vessel walls is by measuring streaming potentials. Experiments described in the present work are extensions of original in vivo streaming potential measurements. In vitro streaming potentials were measured across fresh canine aortae and carotid arteries using Krebs saline serum substitute, logarithmically varying both internal and external electrolyte concentrations. Positive streaming potentials were measured indicating that the blood vessel wall is negatively charged. Streaming potentials increased linearly with increasing flow rate, decreased with increasing internal electrolyte concentration, decreased with increasing external electrolyte concentration, and reversed, becoming positive, with aging of exteriorized artery. Thus the electrical characteristics of the blood vessel wall are dependent on an ionic balance between the blood vessel wall, flowing blood stream, and external environment. The information demonstrates the importance of electrochemical and physicochemical phenomena in the structure and function of the vascular interface and helps explain in vivo conditions conducive to or inhibitory of intravascular thrombosis.
    Zusätzliches Material: 12 Ill.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 37
    Digitale Medien
    Digitale Medien
    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 1 (1967), S. 387-394 
    ISSN: 0021-9304
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Medizin , Technik allgemein
    Notizen: The authors followed the tissue response of a new plastic tube composed of neutral hydrophilic gel, after implantation in the subcutis of rats. They further studied tissue reaction when gel rods were connected by polymerization in situ. After implantation, the gel tubes developed a fine encapsulation but no inflammatory response. The gel rods were connected “end to end” by means of a drop of the polymerizing mixture. The healing proceeded in the same manner with the exception that minute granules of macrocellular elements were formed in the ligament surrounding the polymerization mixture remnats. According to these results, the neutral hydrophilic gel has proved to be a suitable material for implantation.
    Zusätzliches Material: 4 Ill.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 38
    Digitale Medien
    Digitale Medien
    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 1 (1967), S. 371-386 
    ISSN: 0021-9304
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Medizin , Technik allgemein
    Notizen: A new intraoral adhesive bandage composed of gelatin, sodium carboxymethylcellulose, and polyisobutylene backed by a layer of polyethylene film was used by 148 investigators in 1468 patients. The bandage adhered well to the fixed mucosa of the palate, gingiva, and teeth. It adhered less satisfactorily to the loose mucosa of the cheek and floor of the mouth. It did not adhere very well to the tongue. The duration of adhesion of the bandage was at least 5 hr in approximately 87% of all treated cases, and it remained in place for 9-51 hr for more than 50% of all treated patients. Tolerance of the application was good or excellent in 75% of all cases. There was no irritation attributable to the bandage in any patient. The bandage provided an effective means of protecting the vital repair mechanism of a wound during the early hours after extraction. The results of these trials indicate that the new adhesive bandage is safe and that it provides effective cover and protection of wounds and lesions of the mucous surface up to 24 hr.
    Zusätzliches Material: 8 Ill.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 39
    Digitale Medien
    Digitale Medien
    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 1 (1967), S. 395-404 
    ISSN: 0021-9304
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Medizin , Technik allgemein
    Notizen: Sutured, stapled, and methyl- or thickened n-pentyl-2-cyanoacrylate-adhered end-to-end arterial anastomoses were compared in two series of 10 dogs, employing the three 4-mm diameter terminal branches of the aorta for these comparisons. Patency rate, speed of construction, and gross and microscopic appearances were employed as criteria for evaluation. In a series of adult white rabbits the same criteria were applied to compare sutured and thickened n-pentyl-2-cyanoacrylateadhered end-to-end anastomoses of the 2-mm diameter abdominal aorta. Anastomoses adhered with methyl-2-cyanoacrylate were significantly more often thrombosed than any other variety; a marked inflammatory response followed application of this material. Thickened n-pentyl-2-cyanoacrylate adhesive was well tolerated, and the results obtained with this material were equivalent to those obtained by suturing or stapling in the dog, or by suturing in the rabbit.
    Zusätzliches Material: 6 Ill.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 40
    Digitale Medien
    Digitale Medien
    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 1 (1967), S. 405-414 
    ISSN: 0021-9304
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Medizin , Technik allgemein
    Notizen: Corrosion resistance is particularly important in medical treatments requiring implantation of metallic objects in the human body. Unfortunately, weight loss measurements and other conventional corrosion testing techniques are insufficiently sensitive and difficult to adapt to in vivo environments. The linear polarization technique can be used to remotely meaure the corrosion rates of metals implanted in tissue using needle probes. The principles of this technique are reviewed and the results of tests performed on steel, cobalt, and molybdenum implanted in experimental animals are discussed.
    Zusätzliches Material: 7 Ill.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 41
    Digitale Medien
    Digitale Medien
    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 1 (1967), S. 415-425 
    ISSN: 0021-9304
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Medizin , Technik allgemein
    Notizen: The presence of the β1 phase in dental amalgam after 60°C heating has been confirmed by x-ray diffraction, metallography, microhardness tests, and electron beam analysis. It appeared that the γ1 → β1 transformation began at preferred sites, believed to be possibly areas deficient in Hg, and grew outward from these sites. Even after heating for nearly a year, however, some γ1 still remained in the sample.
    Zusätzliches Material: 5 Ill.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 42
    Digitale Medien
    Digitale Medien
    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 2 (1968) 
    ISSN: 0021-9304
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Medizin , Technik allgemein
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 43
    Digitale Medien
    Digitale Medien
    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 1 (1967), S. 427-432 
    ISSN: 0021-9304
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Medizin , Technik allgemein
    Notizen: In vivo and in vitro experiments described herein have demonstrated that the GBH coating is antithrombogenic when placed on PVC, as tested in the blood system of rabbits for periods up to 2 weeks. In vitro clotting times cannot be correlated with the in vivo thrombogenicity of the same implants. For example, dog and man have very similar in vitro clotting times, but very dissimilar in vivo prosthetic thrombosis problems. In vivo and in vitro tests are for the most part not comparable in that they do not measure the same things. However, both in vivo and in vitro tests proved the GBH-treated vinyl to be antithrombogenic. It may be concluded from the available data that a flexible plastic can be treated with GBH and become antithrombogenic for a practicable period of time.
    Zusätzliches Material: 2 Tab.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 44
    Digitale Medien
    Digitale Medien
    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 1 (1967), S. 433-449 
    ISSN: 0021-9304
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Medizin , Technik allgemein
    Notizen: Man-made polymeric materials are being utilized in a number of devices which will be implanted into animals and humans for various periods of time. The diversity of materials and the introduction of new materials into the medical and paramedical professions appear to be increasing at an accelerated rate each year. Even though great advancements have been made by the biomedical engineer and the surgeon in designing and implanting a prosthetic device in the body, less emphasis apparently has been given to the possible or potential hazardous aspects of the material. An implantable material may initiate a body response in two general ways: (1) release of an ingredient from the material to the biological environment and (2) alteration of the material by the biological environment, leading to degradation of the material with its various consequences. If serious future hazards are to be kept to a minimum, greater emphasis must be placed on well-designed toxicity studies of materials which, in turn, could lead to standardized materials for implants.
    Zusätzliches Material: 4 Tab.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 45
    Digitale Medien
    Digitale Medien
    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 2 (1968), S. 1-22 
    ISSN: 0021-9304
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Medizin , Technik allgemein
    Notizen: Several metallic orthopedic implants which failed in service and for which the medical histories are known are comprehensively examined using metallographic techniques and electron microprobe analyses to determine the causes of failure. The results indicate that fatigue is a major cause of failure and that, in all probability, the fatigue is initiated by poor design or poor material.
    Zusätzliches Material: 20 Ill.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 46
    Digitale Medien
    Digitale Medien
    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 2 (1968), S. 43-49 
    ISSN: 0021-9304
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Medizin , Technik allgemein
    Notizen: Tubing made of a polar plastic, polychlorotrifluoroethylene, was electrically polarized while heated. The zeta potential of tubes polarized negatively inside was consistently higher than that of unpolarized tubes. Tubes polarized positively had a much smaller and variable change in zeta potential. The change is apparently not related to the formation of electrets, but may be due to the orientation of pre-existing dipoles.
    Zusätzliches Material: 1 Ill.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 47
    Digitale Medien
    Digitale Medien
    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 2 (1968), S. 23-42 
    ISSN: 0021-9304
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Medizin , Technik allgemein
    Notizen: The effect of phenol and certain phenyl compounds on the different stages of the blood coagulation and fibrinolytic mechanism is investigated. Phenol has a complex action on blood coagulation. In an optimal concentration of 0.3% it produced a definite, though suboptimal platelet factor 3 activity, evolved factor XII, accelerated thrombin-fibrinogen interaction, retarded clot retraction, enhanced the action of streptokinase on plasminogen, and inhibited plasmin. In addition, in the absence of factor XIII and calcium, it increased the solubility of fibrin in urea. Phenyl acetaldehyde, benzyl benzoate, and styrene (phenyl ethylene) accelerated stypven clotting time and thrombin-fibrinogen reaction. Unpolymerized styrene and phenyl ethanol specifically inhibited the action of plasma thromboplastin, formed in a system lacking in factor VIII or IX. A study is also reported on the changes responsible for the stabilization with phenol of brain thromboplastic activity. The action is not purely bactericidal, but is dependent on the presence of brain tissue particles in suspension. The contribution of platelets to plasma thromboplastin formation is examined in the light of these investigations, showing the ability of phosphorus-free compounds to supply a platelet-like activity.
    Zusätzliches Material: 16 Tab.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 48
    Digitale Medien
    Digitale Medien
    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 2 (1968), S. 81-88 
    ISSN: 0021-9304
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Medizin , Technik allgemein
    Notizen: Adult albino rabbits were implanted with disks of 316 and 304 stainless steel in the subperiosteum of the anterior calvarium and the left mandible and in the left paravertebral and thigh muscles. The corresponding opposite sites were sham operated. The histopathological slides revealed that there was variation in thickness of the membrane in sections of both the paravertebral and thigh muscles; one side showing greater reaction than the other, which corresponded with the appearance of the implants. Sections of the calvarium revealed minimal bone and soft tissue reaction, although the implants showed corrosion compatible with soft tissue sites. The mandibular sections revealed extensive bone tissue reactions with minimum masseter muscle reactions, but the appearance of the implants due to corrosion was different than those of all other sites. Moderate eosinophilic infiltration was observed in sections containing deposits of corrosion products.
    Zusätzliches Material: 5 Ill.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 49
    Digitale Medien
    Digitale Medien
    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 2 (1968), S. 89-93 
    ISSN: 0021-9304
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Medizin , Technik allgemein
    Notizen: An alternate correlation of blood coagulation time with surface properties of solids is proposed in that the work of adhesion is used rather than the surface free energy. The overall quality of the two correlations is about the same, but the new method does allow the important data point for glass to also be included. Possible useful future work of this type is discussed.
    Zusätzliches Material: 1 Ill.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 50
    Digitale Medien
    Digitale Medien
    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 2 (1968), S. 51-79 
    ISSN: 0021-9304
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Medizin , Technik allgemein
    Notizen: Bioelectric charge transfer at the blood-wall interface may be a crucial factor affecting thrombosis on implant materials. A program of studies was conducted to determine the electrokinetic and other physical properties of a wide spectrum of materials including organic polymers, metals, inorganics, heterogeneous compounds, and animal tissue. From these tests, materials were selected for in-vivo cannulation experiments. In this manner, a search was made to find a correlation between surface charge characteristics and thrombosis on cardiovascular implant materials. It was found that materials exhibiting a substantial positive charge were prone to rapid thrombosis. No clear correlation can be stated, as yet, regarding the thrombogenecity of highly charged negative surfaces or slightly charged surfaces. However, many heterogeneous materials have exhibited prolonged in-vivo patency. It appears necessary to isolate surface effects from volumetric effects to seek the role of bioelectric charge transfer in blood thrombus formation.
    Zusätzliches Material: 9 Ill.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 51
    Digitale Medien
    Digitale Medien
    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 2 (1968), S. 121-130 
    ISSN: 0021-9304
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Medizin , Technik allgemein
    Notizen: A segmented polyurethane elastomer, originally developed for elastic thread, is now being used for molded prostheses. Chemical, mechanical, and biological properties are described. Hydrolytic stability of this polymer is compared to that of a polyester urethan. Experience with the material used in components of an experimental heart-assist pump has shown excellent flex endurance, wear resistance, and intravascular acceptability.
    Zusätzliches Material: 3 Ill.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 52
    Digitale Medien
    Digitale Medien
    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 2 (1968), S. 131-143 
    ISSN: 0021-9304
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Medizin , Technik allgemein
    Notizen: During the period covered by this investigation, toxicological studies were carried out in hamsters and rabbits. The results of injections, subcutaneously and in the buccal pouch of hamsters, indicated that the silicones used were nontoxic, non-absorbable, and well encapsulated by connective tissue elements with moderate tissue reaction. Further studies of various combinations of roomtemperature vulcanizing silastics indicated similar reactions when injected submucosally in the alveolar ridges and palate of rabbits. The injected materials remained in situ in the injected submucosal area and became well encapsulated by the proliferation of connective tissue and collagenous fibers. There was no evidence of macrophages or foreign body giant-cells in and around the proliferating connective tissue capsule. There were no macroscopic or microscopic signs of tumor formation. The encapsulated masses did not elicit bone resorption when localized adjacent to bone tissue.
    Zusätzliches Material: 12 Ill.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 53
    Digitale Medien
    Digitale Medien
    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 2 (1968), S. 95-119 
    ISSN: 0021-9304
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Medizin , Technik allgemein
    Notizen: The effects of variations in composition and processing on the open-circuit electrode potentials measured as a function of time of amalgams made from silver-tin, silver-tin-copper, silver-tin-zinc, and silver-tin-copper-zinc alloys have been determined at 37°C in distilled water, in saline solution, as well as in acetate and citrate solutions buffered to pH values of 3, 7, and 10. The electrochemical potentials of the alloys measured as a function of time in neutral acetate solutions show anodic polarization from an initial cathodic potential value of approximately 0.1 v with respect to the standard hydrogen electrode to a constant potential level depending upon alloy composition. In neutral acetate solution the potential-time curves of silver-tin amalgams with 7:5 mercury to alloy ratio show a rapid anodic polarization from an initial anodic potential value of 0.28 v to a minimum value of 0.05 v at approximately 1 hr followed by a potential reversal to a plateau value of 0.40 v. For 7:5 amalgams in neutral acetate solutions increases in both the trituration time and in the severity of processing deformation cause a small increase in initial potential, with a decrease in anodic polarization, while an increase in amalgam age lowers both the initial potential value and the longer-time potential plateau. Increasing the mercury content of the amalgam to a 2:1 ratio decreases the rate of potential reversal from the minimum, whereas decreasing the ratio to 4:5 decreases the amount of depolarization from the minimum value. The effects of copper and zinc additions to silver-tin alloys are mixed. In neutral acetate solution the 7:5 ratio amalgams from silver-tin-copper alloys show anodic polarization from the same initial value as the silver-tin amalgams, followed by a region of decreased polarization. Both silver-tin-zinc and silver-tin-copper-zinc alloys exhibit a much higher initial anodic potential (0.78 v), and following the achievement of the potential plateau have a slow anodic polarization to the long-time potential value shown by silver-tin amalgam. Three commercial alloy amalgams were studied in neutral acetate solution. The two amalgams containing zinc have a potential behavior similar to that of the experimental zinc-containing amalgam; the non-zinc amalgam shows a rapid anodic polarization from an initial anodic potential value of 0.24 v, a minimum at 1 hr, and a reversal to the long-time potential values of 0.40 v shown by the zinc-containing amalgam.
    Zusätzliches Material: 14 Ill.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 54
    Digitale Medien
    Digitale Medien
    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 2 (1968), S. 157-163 
    ISSN: 0021-9304
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Medizin , Technik allgemein
    Notizen: Three monomers, β-14C-tagged methyl, n butyl, and n-heptyl α-cyanoacrylate, have been applied to intact skin and split-thickness skin-graft donor sites on rats. The data indicate that the urinary 14C activity is in the order: methyl 〉 n-butyl or n heptyl. Also, the urinary activity, when the monomers are applied to the split thickness skin graft donor sites, is approximately threefold greater than when the monomers are applied to intact skin. The conclusion is that the application of cyanoacrylate monomer to the skin is not only topical in nature, but may involve the internal milieu as well.
    Zusätzliches Material: 1 Ill.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 55
    Digitale Medien
    Digitale Medien
    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 2 (1968), S. 145-155 
    ISSN: 0021-9304
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Medizin , Technik allgemein
    Notizen: Polyelectrolyte complexes are ionic hydrogels formed by the coreaction of two oppositely charged, strongly ionized polyelectrolytes. While insoluble in simple solvents and infusible, these polymers can be fabricated into membranes, fibers, and other shaped articles by casting from ternary solvents. Homogeneous membranes are optically clear, amorphous structures in which the equilibrium gel water content can be controllably varied from ca. 30-90%. The net ion-exchange capacity of the membrane can be varied from zero to ca. 2.0 meq/g, either cationic or anionic. Homogeneous membranes are characterized by unusually high water and gas permeabilities and permeabilities to water and soluble solutes which can be controlled by adjustment of gel water content and ion-exchange capacity. Anisotropic membranes can also be prepared which are high flux molecular ultrafilters for solutes as small as sucrose. The anisotropic membranes have found widespread use in biology for fractionation, concentration, and purification of biopolymers. Homogeneous membranes show promise as analogues for biological membranes. A number of applications are being evaluated in medicine and surgery. These include: vascular grafts, antithrom-bogenic coatings for plastic prostheses, contact lenses, corneal implants, and surgical adhesives. In addition, polyelectrolyte complex membranes are showing considerable promise for artificial kidneys and blood oxygenators.
    Zusätzliches Material: 4 Ill.
    Materialart: Digitale Medien
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  • 56
    Digitale Medien
    Digitale Medien
    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 2 (1968), S. 165-171 
    ISSN: 0021-9304
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Medizin , Technik allgemein
    Notizen: A quantitative method for determining residual ethylene oxide in plastic and rubber catheters using gas-liquid chromatography has been developed. Tests on ethylene oxide stabilized catheters indicated that the amount of ethylene oxide in the catheters decreased as a function of aeration time up to 48 hr. After this period, a steady concentration of ethylene oxide in the catheters appeared to have been reached up to one week's testing.
    Zusätzliches Material: 3 Ill.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 57
    Digitale Medien
    Digitale Medien
    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 2 (1968), S. 183-184 
    ISSN: 0021-9304
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Medizin , Technik allgemein
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 58
    Digitale Medien
    Digitale Medien
    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 2 (1968) 
    ISSN: 0021-9304
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Medizin , Technik allgemein
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 59
    Digitale Medien
    Digitale Medien
    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 2 (1968), S. 187-199 
    ISSN: 0021-9304
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Medizin , Technik allgemein
    Notizen: A rapid mixing and sampling technique was used to study the permeability characteristics of semipermeable aqueous microcapsules (artificial cells). Urea, creatine, creatinine, uric acid, glucose, sucrose, and salicylic acid equilibrated rapidly across nylon microcapsules of 207 μ diameter (e.g., T 1/2 for urea of 3.4 sec). From these results the permeability constants were calculated (e.g., P for urea of 2 × 10-4 cm/sec). Very much the same permeability constants were found for collodion microcapsules. The equivalent pore radius of the membrane of the nylon microcapsules were estimated to be 18 A.
    Zusätzliches Material: 5 Ill.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 60
    Digitale Medien
    Digitale Medien
    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 2 (1968), S. 209-214 
    ISSN: 0021-9304
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Medizin , Technik allgemein
    Notizen: The critical need for purchase specifications for implantable biomedical materials is the focus of this contribution. The elements in development of such specifications are presented with specific reference to a widely used high polymer, polytetrafluoroethylene. A specification for sheet or film of this plastic, as instituted by a major urban hospital, is presented in detail.
    Zusätzliches Material: 2 Tab.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 61
    ISSN: 0021-9304
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Medizin , Technik allgemein
    Notizen: Previous observations of pseudointimal organization within impermeable cardiovascular prostheses indicated that rapid spontaneous healing was dependent upon proximity of host vascular tissue at the suture line. Autologous connective tissue fragments were prepared from skeletal muscle biopsies by blender-mincing muscle tissue. The fragments were embedded in the fabric used to line the inner wall of arterial prostheses. A tightly fitting piston was drawn through the prosthesis, forcing the suspended tissue fragments to flow around the piston and become entwined in the loops of the velour fabric. The arterial prostheses prepared in this way were inserted as replacements for segments of canine abdominal aorta. This in vivo culture system supported cellular proliferation and pseudointimas healed uniformly. Pseudointimas of paracorporeal pumps in operation for as long as 5 weeks did not show signs of healing. The same principle of filtration of tissue fragments into a lining fabric was applied to diaphragms of left ventricular bypass pumps. This type of paracorporeal pump supported in vivo culture of implanted fragments.
    Zusätzliches Material: 7 Ill.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 62
    Digitale Medien
    Digitale Medien
    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 2 (1968), S. 215-230 
    ISSN: 0021-9304
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Medizin , Technik allgemein
    Notizen: Maximum extraction stress and integrated extraction work were measured for sutures implanted for 3, 7, and 14 day periods. Six common non-absorbable sutures, representative of braided and monofilamentary forms, were implanted subdermally and were used for cutaneous incision closure with purebred pointer dogs. The data show: (1) Braided sutures, polyester/Teflon, silk-type B, and silk-silicone interacted with peripheral tissue to a significantly greater degree than the monofilamentary types, nylon, polypropylene, and polyethylene; (2) polyester-Teflon braided suture interacted to a lesser degree than the other braided sutures; (3) the relatively intense interaction of plain silk and silicone-treated silk appears to reflect the combined effects of mechanical aspects of braiding and of biochemical response; and (4) all braided sutures swelled over the implantation periods with as much as a 70% increase in diameter after 14 days for silk.
    Zusätzliches Material: 13 Ill.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 63
    Digitale Medien
    Digitale Medien
    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 2 (1968), S. 237-243 
    ISSN: 0021-9304
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Medizin , Technik allgemein
    Notizen: A hydrophilic plastic material (USA trademark Hydron), developed by Wichterle and Lím, was used as a sponge for augmentation of breasts in the clinic for plastic surgery. The preparation of the prosthesis and the operational procedures are described.
    Zusätzliches Material: 2 Ill.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 64
    Digitale Medien
    Digitale Medien
    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 2 (1968), S. 231-235 
    ISSN: 0021-9304
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Medizin , Technik allgemein
    Notizen: ATP-diphosphohydrolase, trypsin, and chymotrypsin have been insolubilized by lattice-entrapment using hydrophilic polyacrylamide gel and hydrophobic Silastic matrices. The entrapped enzymes were stable and unaffected by washing or wet storage. Thermal inactivation properties of polyacrylamide-entrapped ATP-diphosphohydrolase were different from those of the same enzyme in solution. Several substrates were used for each of the proteolytic enzymes. Esterase activities of both trypsin and chymotrypsin were unaltered by entrapment within Silastic. The entrapment of enzymes and other active proteins is potentially of consequence in continuous-flow substrate conversion systems. Silastic with a surface proteolytic activity derived from an entrapped enzyme is of possible medical utility for implantation elements.
    Zusätzliches Material: 3 Tab.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 65
    Digitale Medien
    Digitale Medien
    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 2 (1968), S. 279-279 
    ISSN: 0021-9304
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Medizin , Technik allgemein
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 66
    ISSN: 0021-9304
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Medizin , Technik allgemein
    Notizen: A careful solvent-exchange procedure followed by liquid-phase reaction of ethyleneimine with cellulose film in a nonpolar solvent provides an effective method of uniformly aminoethylating cellulose. The protonated aminoethyl groups on the cellulose can then ionically bind heparin, a blood anticoagulant. Heparinized aminoethylated cellulose tubing at low levels of aminoethylation (ca. 0.2-0.3% nitrogen) exhibited excellent antithrombogenic properties as well as excellent mechanical strength properties. The in vitro tests demonstrated indefinitely long whole-blood clotting times with normal thrombin times. In the in vivo experiments, the heparinized aminoethylated cellulose tubing provided extended patency when implanted intravascularly in the regions of low blood flow rate (infra renal inferior vena cava of dogs). A principal use of this film is in the artificial kidney.
    Zusätzliches Material: 5 Ill.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 67
    Digitale Medien
    Digitale Medien
    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 14 (1980), S. 31-40 
    ISSN: 0021-9304
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Medizin , Technik allgemein
    Notizen: Metallurgical observations of phenomena which influence the clinically successful performance of permanent implants and implant materials are reported. The effect of casting voids in cast cobalt chromium femoral stems of total hip replacements is discussed first. Pitting corrosion occurred in a retrieved stainless-steel implant type AISI 316 containing 2.7% Mo. The fractographic pattern of this device retrieved for fatigue failure shows typical characteristics of corrosion-enhanced fatigue.
    Zusätzliches Material: 3 Ill.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 68
    Digitale Medien
    Digitale Medien
    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 14 (1980), S. 11-21 
    ISSN: 0021-9304
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Medizin , Technik allgemein
    Notizen: The outer and inner surfaces of six commercial endotracheal tube cuffs were characterized using scanning electron microscopy (SEM) and energy dispersive x-ray analysis. Lateral tracheal wall pressure (LWP) was measured at various steps of cuff inflation using a mock-trachea system. The surface characteristics of the cuffs were found to vary widely. The surface of the Lanz cuff was relatively smooth but showed a regular array of circular depressions 0.8 μm in diameter. Uniform spheres also 0.8 μm in diameter were distributed through the thickness of the membrane. The American Hi-Lo cuff surface was also relatively smooth but was covered widely with flakes of material which x-ray showed to be a clay-like substance containing aluminum, silica, and potassium. The Harlake cuff was covered widely with roughly spherical, 5-μm-diam particles, probably starch granules. The membrane itself was smooth even at 3,000X. The Foregger cuff had a rough surface and was covered with the same clay-like particles seen on the American cuff. The inner surface with irregular, uneven areas were surrounded by fissures. The Rusch Armored tube cuff was completely covered by a continuous 2-μm-thick chlorinated coating. The surface was highly convoluted and irregular. The three cuff membranes showing relatively smooth surfaces, Lanz, American and Harlake, also produced relatively low LWP at various points of cuff inflation. While we have no data to indicate that cuff surface smoothness correlates with tracheal morbidity, it would seem prudent to select cuffs that produce low LWP's with smooth surfaces for clinical use.
    Zusätzliches Material: 7 Ill.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 69
    Digitale Medien
    Digitale Medien
    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 14 (1980) 
    ISSN: 0021-9304
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Medizin , Technik allgemein
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 70
    Digitale Medien
    Digitale Medien
    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 14 (1980), S. 55-64 
    ISSN: 0021-9304
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Medizin , Technik allgemein
    Notizen: Bioglass, which has a composition of sodium carbonate, calcium carbonate, phosphorous pentoxide and silica, has been shown to bond to living bone. This ability is dependent on controlled surface reactions. Investigators with 45S5 bioglass have demonstrated that the formation of a SiO2-rich layer and a calcium phosphate film on its surface in an aqueous environment is associated with the film bonding the bioglass to bone. The objects of this research were: 1To study SiO2 dependence on the formation of a silica-rich layer and calcium phosphate films on a bioglass surface in a simulated physiological solution, and2To establish a correlation between in vitro surface reactions and in vivo bonding ability.It was discovered that three types of reactions occur in a simulated physiological solution depending on bioglass composition: 1A calcium phosphate film and SiO2-rich layer form simultaneously and the reaction rate is fast for bioglasses which have a lower content of SiO2 (∼46 mol% SiO2).2A SiO2-rich layer forms first and a calcium phosphate film develops later between the aqueous environment and the SiO2-rich layer for bioglasses whose SiO2 content is between 46-55 mol %.3A calcium phosphate film does not form for glasses whose SiO2 content is more than 60 mol %.
    Zusätzliches Material: 8 Ill.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 71
    Digitale Medien
    Digitale Medien
    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 14 (1980), S. 93-106 
    ISSN: 0021-9304
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Medizin , Technik allgemein
    Notizen: Methods by which in vitro heterogeneous phase degradation rates of the poly(n-alkyl α-cyanoacrylates) have been directly obtained are described. The data indicate that the rates of degradation in aqueous buffer solutions depend not only upon pH of the medium and length of the monomer alkyl side chain, but also critically upon polymer particle specific surface, particle size, polymer molecular weight, and molecular weight distribution. A modification of the currently held theory of degradation of these polymers is required, and postulated.
    Zusätzliches Material: 5 Ill.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 72
    Digitale Medien
    Digitale Medien
    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 14 (1980), S. 23-29 
    ISSN: 0021-9304
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Medizin , Technik allgemein
    Notizen: Three-dimensional finite element analysis (FEA) has been used to determine the implant-bone interface characteristics of bioglass dental implants. The results of the FEA were verified by comparison with the results of mechanical testing performed on animal implant specimens. The results of the study showed that the assumption of a discontinuous change of elastic properties at the bone-implant interface was a poor assumption for the bioglass implants. Interface elastic moduli of 354.0, 155.0, and 47.0 MPa for conditions of 25, 50, and 100% tissue attachment were determined for the bioglass implants.
    Zusätzliches Material: 3 Ill.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 73
    Digitale Medien
    Digitale Medien
    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 14 (1980), S. 1-10 
    ISSN: 0021-9304
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Medizin , Technik allgemein
    Notizen: Contact angle studies have been carried out on plasma protein layers adsorbed on selected polymer surfaces under buffered saline at 37°, in an attempt to demonstrate directly a recent suggestion that the interfacial free energy between such protein layers and surrounding liquid phase should be zero at equilibrium. Although an initial contact angle of 180° was always obtained, the angle decayed slowly to a stationary value which varied for any one drop on each polymer surface. The stationary values could be reasonably correlated with the reversible work of adhesion predicted for each polymer/protein combination, suggesting that protein desorption from the solid surface is a dominant event in the contact angle decay process. It is concluded that the data bear more relevance to the protein layer/polymer interface than to the protein layer/solution interface, and that the contact angle technique is not a suitable technique for studying the latter on biomaterials.
    Zusätzliches Material: 3 Ill.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 74
    Digitale Medien
    Digitale Medien
    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 14 (1980), S. 83-90 
    ISSN: 0021-9304
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Medizin , Technik allgemein
    Notizen: Distributions of Ca-to-Ca distances have been obtained from the crystal structure of hydroxyapatite for all biologically significant planes. Most frequently, calcium ions are separated by about 4, 6.3, 7.9, and 9.0 to 9.6 Å. Frequent occurrence of distances at 10.4, 11.8, and 12.6 Å result from a Ca ion in one repeating unit being paired with a Ca in another unit cell.
    Zusätzliches Material: 4 Ill.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 75
    ISSN: 0021-9304
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Medizin , Technik allgemein
    Notizen: Individuals who suffer extensive loss of skin, commonly in fires, are acutely ill, in danger of succumbing either to massive infection or to severe fluid loss. Patients who survive these early threats must often cope with problems of rehabilitation arising from deep, disfiguring scars and crippling contractures. In this report we describe the physiocochemical, biochemical, and mechanical considerations that form the basis for two-stage design of a membrane useful as an experimental wound closure. Stage 1 of the design, applicable to short-term acute use, calls for a membrane which displaces efficiently air pockets from a carefully prepared woundbed, free of weak boundary layers, and maintains the moisture flux through the wound at an optimal level. Optimization of the surface energy modulus of elasticity, energy to fracture and moisture permeability of the membrane are among the essential attributes of Stage 1 design. Stage 2 of the design, applicable to long-term, chronic use, focuses on a nonantigenic membrane which performs as a biodegradable template for synthesis of neodermal tissue. A survey of candidate materials suggests reasons for selection of a porous, crosslinked collagen - glycosaminoglycan coprecipitate as the chemical basis of an evolving design which was initiated 10 years ago. Over the past several years a set of membranes has been iteratively designed on this basis and has been used to cover satisfactorily large experimental fullthickness skin wounds in guinea pigs. Such membranes have effectively protected these wounds from infection and fluid loss for over 25 days without rejection and without requiring change or other invasive manipulation. When appropriately designed for the purpose, the membranes have also strongly retarded wound contraction and have become replaced by newly synthesized, stable connective tissue. Several rules relating the molecular structure and morphology of these membranes to cellular response of adjacent tissue have also been derived. This report is the first in a series which details the methodology of preparation and the record of performance.
    Zusätzliches Material: 1 Ill.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 76
    Digitale Medien
    Digitale Medien
    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 14 (1980), S. 177-180 
    ISSN: 0021-9304
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Medizin , Technik allgemein
    Zusätzliches Material: 3 Ill.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 77
    Digitale Medien
    Digitale Medien
    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 14 (1980), S. 181-181 
    ISSN: 0021-9304
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Medizin , Technik allgemein
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 78
    Digitale Medien
    Digitale Medien
    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 14 (1980), S. 211-224 
    ISSN: 0021-9304
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Medizin , Technik allgemein
    Notizen: Several kinds of polyamide microcapsules containing mammalian hemolysate were prepared by making use of the interfacial polycondensation reaction between diamines and terephthaloyl dichloride and their blood compatibility in terms of platelet adhesion was examined aiming at their ultimate clinical use as artificial red blood cells. It was found that rabbit platelets adhere onto the hemolysate-loaded microcapsules in the presence of the plasma, while no platelet adhesion takes place in the absence of the plasma. This was interpreted as indicating an important role of plasma components in platelet adhesion. Moreover, platelet adhesion was observed to be facilitated by negative charges on the surface of the hemolysate-loaded microcapsules; the more negatively the surface was charged, the more easily the platelets adhered onto the surface. Finally, the present method of assessing platelet adhesion suggested the possibility of its use for the kinetic study of platelet adhesion since it allowed us to make numerical evaluation of platelet adhesion as a function of time.
    Zusätzliches Material: 12 Ill.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 79
    Digitale Medien
    Digitale Medien
    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 14 (1980), S. 251-268 
    ISSN: 0021-9304
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Medizin , Technik allgemein
    Notizen: The thrombogenicity of five suture materials - polypropylene (Prolene), polyester (Mersilene), polyglactin 910 (Vicryl), nylon (Ethilon), and silk - was examined in vivo by scanning electron microscopy. The most blood-compatible material appeared to be Prolene. A rather satisfactory antithrombogenciity was shown by Mersilene, in comparison with which Ethilon and Vicryl provided less thromboresistance. The possible connection between the chemical changes which occur during the hydrolysis of Vicryl and its blood compatibility is discussed. Of the tested materials, silk proved to be the most thrombogenic. This study shows that the thrombogenicity of a suture material could be easily and conveniently tested in an experimental model by scanning electron microscopy, thus enabling the first choice of a suitable suture for the cardiovascular surgery, before one continues with other more sophisticated methods for the evaluation of thromboresistance.
    Zusätzliches Material: 15 Ill.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 80
    Digitale Medien
    Digitale Medien
    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 14 (1980), S. 289-309 
    ISSN: 0021-9304
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Medizin , Technik allgemein
    Notizen: It is known that tissues surrounding the site of an implanted prosthetic alloy are exposed to increased concentrations of the metals comprising the alloy. However, the exact identity and concentration of such metallic products are usually unknown, thus limiting the possibilities for quantifying any observed toxicological response to the metals. This report describes some of the effects of increased concentrations (7.5-30 μg/ml; 1-5 × 10-4M) of cobalt (as CoCl2·6H2O) and of nickel (as NiCl2·6H2O) on the growth and morphology of cultured mouse fibroblasts. Ultrafiltration experiments indicated that much of the total Co or Ni present in cell culture medium could become bound to macromolecular serum components of the medium. Morphological changes and depressions in the cell growth rate were found to result from high concentrations (15-30 μg/ml) of either Co or Ni. However, lower concentrations of nickel may have produced some stimulation of cell growth, whereas all concentrations of Co studied were found to depress the rate of cell growth. The growth rate of actively proliferating fibroblasts was quite sensitive to variations in the concentration of either cobalt or nickel. Increased concentrations of cobalt or nickel, therefore, might also affect the normal reconstructive activity of fibroblasts in vivo.
    Zusätzliches Material: 9 Ill.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 81
    Digitale Medien
    Digitale Medien
    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 14 (1980), S. 329-338 
    ISSN: 0021-9304
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Medizin , Technik allgemein
    Notizen: In vitro and in vivo experiments were performed on polyglycolic acid and plain catgut sutures to study the effects of bacteria on their rate of degradation. Experiments with Strep, mites, E. coli and Staph. albus in culture showed that the polyglycolic acid sutures degraded faster in broth controls than in a broth containing bacteria as measured by the loss in breaking strength. No difference was observed with the catgut. Polyglycolic acid sutures in subcutaneous sites in rats inoculated with Staph. albus again degrade slower than in similar wounds which were not deliberately infected. With high bacterial counts, the catgut showed the reverse trend although no differences were noted at lower counts.
    Zusätzliches Material: 2 Ill.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 82
    Digitale Medien
    Digitale Medien
    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 14 (1980) 
    ISSN: 0021-9304
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Medizin , Technik allgemein
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 83
    Digitale Medien
    Digitale Medien
    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 14 (1980), S. 359-371 
    ISSN: 0021-9304
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Medizin , Technik allgemein
    Notizen: Two types of fracture toughness specimen, the tapered cleavage (TC) and single edge notch (SEN), are compared. Their reproducibility, accuracy, and ease of preparation are investigated. The fracture toughness of four types of acrylic resin, heat cured, autopolymerized, injection molded, and high impact resistant, has been determined by one or both of the above methods. High impact acrylic proved too ductile for either of the specimens to be used to assess K1c; however, these deviations from brittle behavior were revealed by the tests and some insight into impact resistance was gained. The SEN specimens proved capable of distinguishing between the fracture toughness characteristics of the four types of denture base acrylics and proved easy to fabricate. The TC specimens proved difficult to fabricate requiring specialized equipment; however, once made, the specimens revealed more of the fracture process than did the SEN specimens.
    Zusätzliches Material: 9 Ill.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 84
    Digitale Medien
    Digitale Medien
    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 14 (1980), S. 427-434 
    ISSN: 0021-9304
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Medizin , Technik allgemein
    Notizen: The amount of methyl methacrylate monomer present in bone tissue immediately adjacent to implanted bone cement that has polymerized in vivo has been determined. Poly(methyl methacrylate) was implanted into the distal femoral condyle of the dog and allowed to polymerize. At various times following polymerization, samples were removed and sections adjacent to the cement were cut and subjected to homogenization followed by liquid gas chromatographic determination of the amount of methyl methacrylate monomer present. The highest concentration of methyl methacrylate monomer present in bone tissue was 0.140% in the 1000 μm of bone tissue adjacent to bone cement immediately after polymerization of the cement. The concentration was very similar (0.137%) 1 hr after cement polymerization, but dropped off rapidly following that with no free methyl methacrylate monomer present in bone tissue adjacent to cement after 4 hr following cement polymerization.
    Zusätzliches Material: 2 Ill.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 85
    Digitale Medien
    Digitale Medien
    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 14 (1980), S. 447-454 
    ISSN: 0021-9304
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Medizin , Technik allgemein
    Notizen: An evaluation of the biophysical changes of methylcholanthrene induced tumor (M4) in laboratory animals receiving four different alloplastic implants was conducted. The implants are silicone, polyether urethane, poly(methyl methacrylate), and bioglass. The tumor was allowed to grow to a large size in 28 days and then removed by shelling it from the surrounding tissue. Three different analytic volumetric measurements were carried; size in cm3, volume in milliliters and weight in grams. Statistical analysis on the three different analytic measurements did not disclose any significant differences in tumor growth potential between the control and the experimental groups. We conclude that in this study we were unable to demonstrate any tumor “facilitation” effect by any of the implantable polymers used. Therefore, there is no contraindication in using the polymers to reconstruct defects produced by cancer ablative procedures.
    Zusätzliches Material: 2 Tab.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 86
    Digitale Medien
    Digitale Medien
    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 14 (1980), S. 467-476 
    ISSN: 0021-9304
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Medizin , Technik allgemein
    Notizen: Thrombin adsorbed onto Cuprophane or poly(vinyl chloride) (PVC) was shown to be inactive with respect to amidase activity. Desorbed thrombin from these two artificial surfaces showed only low amidase activity. However, in the presence of albumin, the surface-bound thrombin appeared to exhibit increased amidase activity. This apparent activity may be due to the action of thrombin displaced from the surfaces by albumin. Thrombin bound to Cuprophane or PVC was shown to be capable of reacting with antithrombin III (AT III) only in the presence of heparin. On the other hand, AT III bound to Cuprophane or PVC was unable to react with thrombin in either the absence or presence of heparin. Fibrin formation on or at surfaces was demonstrated by phase contrast microscopy when Cuprophane or PVC pretreated with thrombin and carefully rinsed was incubated in a fibrinogen solution. This fibrin formation is time dependent and likely is the result of direct interaction of adsorbed thrombin with fibrinogen in solution. Glass, Cuprophane, and PVC pretreated with thrombin were shown to attract more platelets than respective untreated surfaces. The enhancing effect of adsorbed thrombin on platelet adhesion was similar to the enhancing effect of adsorbed fibrinogen. Thrombin adsorbed onto PVC and crosslinked by glutaraldehyde treatment was shown to be antigenically active with a 125I-labeled monospecific antithrombin IgG produced in rabbits. No other plasma proteins adsorbed singly or from plasma or serum onto PVC reacted significantly with the antithrombin IgG preparation. The possible significance of these observations is discussed.
    Zusätzliches Material: 2 Ill.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 87
    Digitale Medien
    Digitale Medien
    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 14 (1980), S. 435-446 
    ISSN: 0021-9304
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Medizin , Technik allgemein
    Notizen: The effect of thermal coefficient of expansion (α) mismatch on porcelain-metal bonding is frequently referred to in the dental literature. Thermally induced stresses may develop at metal-porcelain system interfaces due to differences in the coefficients of thermal expansion of the porcelains, metals, and metal oxides. The objective of this research is to characterize alloy and porcelain expansion behavior as a first step in developing a more specific definition of thermal compatibility. It is clear from comparisons of porcelain data and alloy data that the porcelain has expansion characteristics which are quite different from those of the alloys. The overall differences in values between these alloys and porcelains constitute a mismatch. First run dilatometric heating measurements for porcelain yield large differences between ΔL/L and α values as compared to cooling measurements. For a comparison of alloy and porcelain expansion characteristics, data should be obtained at several temperatures up to the glass transition temperature (Tg) of the porcelain.
    Zusätzliches Material: 2 Ill.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 88
    Digitale Medien
    Digitale Medien
    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 14 (1980), S. 455-466 
    ISSN: 0021-9304
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Medizin , Technik allgemein
    Notizen: This short report concentrates on a close look at the immunological status of experimental animals which were implanted with a known dose of tumor and polymer implant. The implanted polymers used represented the most common biocompatible materials employed in current surgery. The immunological studies all were done in vitro on the cellular level. The studies suggested that there is a noticeable change of the immune system when inorganic biocompatible polymers are used in experimental animals.
    Zusätzliches Material: 3 Ill.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 89
    Digitale Medien
    Digitale Medien
    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 14 (1980), S. 487-497 
    ISSN: 0021-9304
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Medizin , Technik allgemein
    Notizen: The linear, crosslinked amylose-succinate hemostatic agent, IP760, has been evaluated for its interaction with aminoglycosidic antibiotics. The highly structured polymer appears to act as a cationic exchange resin which binds the basic aminoglycosides. Binding of these agents to IP760 is reversed by increased pH and/or increased ionic strength. Dialysis experiments demonstrated that 85 and 90% of the bound gentamicin was released at pH 7.5 and 8.0, respectively, over a period of 36 hr. Formation of the IP760-antibiotic complexes suggests potential medicinal use for hemostasis and slow release of the antibiotic for prophylaxis of postsurgical contamination or infection.
    Zusätzliches Material: 4 Ill.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 90
    Digitale Medien
    Digitale Medien
    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 14 (1980), S. 477-485 
    ISSN: 0021-9304
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Medizin , Technik allgemein
    Notizen: A series of membranes was prepared by air-drying the thin layers of N-acyl- and N-arylidene-chitosan gels. Their flow rates of water and permeabilities of various compounds were examined. N-Acylchitosan membranes were stable in both dilute acid and alkali, but N-arylidene-chitosan membranes were unstable in dilute acid. N-Acetylchitosan membranes were stable in formic acid at room temperature for up to 7 hr. The flow rates of water through N-acetylchitosan membranes were 10.0-23.6 × 10-3 ml/cm2 min under a pressure of 3 kg/cm2, and were unchanged by the membrane thickness (12-60 μm). The increase of carbon numbers for N-acyl groups caused a slight decrease in the flow rates, and the flow rates were decreased by partial O-acetylation of N-acetylchitosan membranes. The flow rate of water through chitosan membranes (thickness 30-35 μm) was 7.1 × 10-4 ml/cm2 min, which was decreased by an increase in the membranes thickness. Low-molecular-weight compounds (MW 〈 2900) passed through these membranes, but high molecular-weight compounds (MW 〉 13,000) did not pass through.
    Zusätzliches Material: 3 Ill.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 91
    Digitale Medien
    Digitale Medien
    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 14 (1980), S. 529-531 
    ISSN: 0021-9304
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Medizin , Technik allgemein
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 92
    Digitale Medien
    Digitale Medien
    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 14 (1980), S. 499-509 
    ISSN: 0021-9304
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Medizin , Technik allgemein
    Notizen: Kinetics of platelet adhesion from suspension to various substrates leads to Langmuir isotherm types of curves, both for suspensions in which the platelets were isolated by means of gel filtration as well as by centrifuging and washing. The level of platelet adhesion increases with increasing surface tension of the substrate. These results cannot be explained on the basis of the theoretical transport model of Ruckenstein et al. The plot of the platelet adhesion at equilibrium vs. γsv brings the observations in yet closer agreement with thermodynamic predictions based on free energy calculations than was found previously for the adhesion of platelets after short contact times between platelet suspension and substrate.
    Zusätzliches Material: 6 Ill.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 93
    Digitale Medien
    Digitale Medien
    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 14 (1980), S. 537-543 
    ISSN: 0021-9304
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Medizin , Technik allgemein
    Zusätzliches Material: 8 Ill.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 94
    Digitale Medien
    Digitale Medien
    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 14 (1980), S. 533-535 
    ISSN: 0021-9304
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Medizin , Technik allgemein
    Notizen: A highly reproducible seeded crystal growth method has been used to study enamel mineralization in the presence of traces of fluoride ion. The resulting increased rate of remineralization over a range of calcium phosphate supersaturation may be attributed to the formation of surface fluorapatite.
    Zusätzliches Material: 1 Ill.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 95
    Digitale Medien
    Digitale Medien
    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 14 (1980), S. 545-545 
    ISSN: 0021-9304
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Medizin , Technik allgemein
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 96
    Digitale Medien
    Digitale Medien
    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 14 (1980) 
    ISSN: 0021-9304
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Medizin , Technik allgemein
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 97
    Digitale Medien
    Digitale Medien
    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 14 (1980), S. 511-528 
    ISSN: 0021-9304
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Medizin , Technik allgemein
    Notizen: Several methods are compared for preparing collagen-glycosaminoglycan (GAG) membranes of high or low porosity. Collagen-GAG membranes have been used to cover satisfactorily large experimental full-thickness skin wounds in guinea pigs over the past few years. Methods studies as means for controlling pore size are confined to purely physical processes which do not require use of additives or chemical reagents to form the porous membrane. We find that membranes, initially swollen in distilled water or saline, shrink linearly to no less than 94% of original dimension after freeze drying; to 75% after critical point drying (from CO2, following water-ethanol exchange); and to 41% of original dimension following air drying from the swollen state. Scanning electron microscopic study of the pore structure resulting from each drying procedure confirms our major conclusion: A carefully designed freeze drying process, two variants of which are described in detail, yields membranes with the highest mean pore size, as measured by quantitative stereological procedures. Critical point drying gave significantly more shrinkage and a lower mean pore size than either one of the two freeze drying procedures used.
    Zusätzliches Material: 8 Ill.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 98
    Digitale Medien
    Digitale Medien
    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 14 (1980), S. 567-586 
    ISSN: 0021-9304
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Medizin , Technik allgemein
    Notizen: Repair or replacement of the damaged anterior cruciate ligament (ACL) is a significant clinical problem. A design utilizing ultrahigh-molecular-weight polyethylene (UHMWPE) was developed and marketed by an orthopaedic device manufacturer. Mechanical failure rates of greater than 10%/year postoperatively raised the issue of the adequacy of UHMWPE in that design. A study has been made to estimate the forces in the human anterior cruciate ligament for young, middle age, and older patients and to thus derive the minimum materials requirements for a now withdrawn prosthetic anterior cruciate ligament (PACL) design. It is concluded that UHMWPE does not possess adequate yield, creep, or fatigue properties to meet the design. Furthermore, consideration of the varying requirements on the PACL, due to differences in age and activity levels of patients, suggest that a band-type design offers a better possibility of achieving adequate materials performance in the ACL prosthetic replacement.
    Zusätzliches Material: 3 Ill.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 99
    Digitale Medien
    Digitale Medien
    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 14 (1980), S. 547-556 
    ISSN: 0021-9304
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Medizin , Technik allgemein
    Notizen: The polarization resistance and anodic polarization curves of three amalgam types were determined in saline solution. Corrosion currents were determined by extrapolation of anodic Tafel slopes. A good correlation was found between corrosion currents and reciprocal polarization resistances, according to Ic = 0.02/PR.
    Zusätzliches Material: 3 Ill.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 100
    Digitale Medien
    Digitale Medien
    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 14 (1980), S. 557-566 
    ISSN: 0021-9304
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Medizin , Technik allgemein
    Notizen: The mechanical properties of the hydrogel membrane of poly(methyl methacrylate-N-vinylpyrrolidone) were studied for the purpose of making soft contact lenses for extended wear. The dependence of tensile fracture energy, flexibility, and recovery from deformation on the water content and thickness of the hydrogel membrane was studied. Reducing the thickness of a lens was found to exert a more advantageous effect than increasing its water content on maximizing the tensile fracture energy under the condition of an adequate supply of oxygen to the cornea through the contact lens. As long as its water content is controlled between 63 and 78%, the contact lens made of poly(methyl methacrylate-N-vinylpyrrolidone) has the flexibility on the same order as that of conventional soft contact lenses of poly(2-hydroxyethyl methacrylate). The rate of recovery from deformation increases with water content, and the residual elongation is negligible in the range of water content over about 70%. It is concluded that practical requirements for use of these contact lenses, determined by these three mechanical properties, can be satisfied at the same time if the water content of the contact lens is adjusted at about 70%.
    Zusätzliches Material: 6 Ill.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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