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  • Articles  (102)
  • Polymer and Materials Science  (102)
  • Aircraft Propulsion and Power
  • Life and Medical Sciences
  • 1975-1979  (102)
  • 1950-1954
  • 1975  (102)
  • Technology  (102)
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  • Articles  (102)
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  • 1975-1979  (102)
  • 1950-1954
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  • 1
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    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 9 (1975), S. 207-211 
    ISSN: 0021-9304
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine , Technology
    Notes: The surface properties of Ag3Sn are important in the amalgamation process so that mechanical abrasion is generally necessary to get a satisfactory amalgam. Therefore, the present study was undertaken to characterize the surface of Ag3Sn after several types of surfaces treatments.Homogeneous polycrystalline rods of Ag3Sn were prepared in vacuo from high purity (99.99%) Ag and Sn. Specimens were sliced from these rods and prepared as follows: (1) mechanically polished, (2) polished as in (1) and allowed to sit in air for three days and (3) polished as in (1) and electrolytically etched. Each of these specimens was examined by Auger electron spectroscopy.The results showed that after mechanical abrasion the surface film was primarily oxide and the Ag to Sn ratio was lower than the bulk composition, indicating preferential oxidation of Sn. After sitting in air sulfur was also present on the surface and the Ag to Sn ratio was greater than that immediately after polishing, indicating the formation of Ag2S. After electrolytic etching some oxide was still present, but only a trace of sulfide was found. However, the Ag to Sn ratio was greater than that for mechanically polished specimens, indicating preferential dissolution of Sn. Therefore, it is seen that the surface preparation of Ag3Sn has a marked effect on Ag and Sn concentrations and the nature of films at the surface.
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  • 2
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    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 9 (1975), S. 255-256 
    ISSN: 0021-9304
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
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  • 3
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    Journal of Biomedical Materials Research 9 (1975), S. 265-272 
    ISSN: 0021-9304
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine , Technology
    Notes: A streaming potential experiment was conducted on in vitro bone to determine the effects polyvalent salts have on bone zeta potential. Polyvalent metal salts would be introduced into local physiological electrolytes by corrosion of a metal implant or dissolution of a ceramic implant. It was hypothesized that a change in zeta potential of mineralized tissue, resulting from the introduction of polyvalent salts, could be a cause of tissue instability at the implant interface. Zeta potentials measured in bone were on the order of a few millivolts. Strongly hydrolytic metal cations such as Al+3 and Fe+3 did not have sufficient activity in buffered neutral electrolytes to alter bone zeta potential. Results suggest that less hydrolytic cations of high valence, and large polarizable anions may affect bone zeta potential.
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  • 4
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    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 9 (1975), S. 315-326 
    ISSN: 0021-9304
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine , Technology
    Notes: The wettability characteristics of the contact lens material, PHEMA, with respect to water have been determined by using the sessile drop, and the captive air bubble techniques of contact angle goniometry. It is concluded that on PHEMA gels water does not spread spontaneously. Large hysteresis has been observed in the advancing and receding contact angles. This suggests that this hydrogel surface is capable of changing its free energy through reorientation of the polymer side chains and chain segments depending on the nature of the adjacent phase. The water content of the gels does not appear to have an effect on water wettability in the hydration range investigated. The minor wettability differences among the various gels studied were most likely due to differences in surface structure and segmental mobility due to inherent variations in the method of preparation. Small but consistent differences were found between the contact angles measured by the captive bubble method and those obtained by the sessile drop method, the former values being higher. These differences may not be method-related artifacts and cannot be explained at the present time.
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  • 5
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    Journal of Biomedical Materials Research 9 (1975), S. 453-463 
    ISSN: 0021-9304
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine , Technology
    Notes: Dogs were dialyzed with collagen and cuprophane membranes, human renal failure patients were dialyzed with cuprophane membranes, and samples of the membranes were observed by scanning electron microscopy at different time periods. Fixation was done in glutaraldehyde and cacodylate buffer, and samples were dried at the critical point. All cellular elements were well preserved and appeared viable. Cuprophane adsorbed platelets almost selectively in dog dialyses, whereas collagen adsorbed a smaller number and more heterogeneous group of cells. In contrast to these findings, when cuprophane was used in clinical dialyses, the cell population was predominantly polymorphonuclear leukocytes.
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  • 6
    ISSN: 0021-9304
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine , Technology
    Notes: The concept of surface-active comonomers of higher functionality is propsed as a means of increasing reliability of the bonding between preventive and restorative dental materials and tooth structures.
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  • 7
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    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 9 (1975) 
    ISSN: 0021-9304
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
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  • 8
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    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 9 (1975), S. 384-384 
    ISSN: 0021-9304
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
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  • 9
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    Journal of Biomedical Materials Research 9 (1975), S. 1-7 
    ISSN: 0021-9304
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine , Technology
    Notes: Using rats as a model, porous discs of RPG carbon and polypropylene and polyethylene were localized subperiosteally and supraperiosteally in the skull. Bone and blood vessels grew into the discs, which had adequate pore size, when placed in direct contact with bone. No bone was generated from the periosteum. Both plastic materials were estimated to be better than carbon for use in osseous reconstructive work. More long term material-tissue stability and reaction studies should be performed.
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  • 10
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    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 9 (1975), S. 67-72 
    ISSN: 0021-9304
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine , Technology
    Notes: A new grade of graphite - isotropic, fine-grained, and of superior strength - has been produced at the Oak Ridge National Laboratory. The possibility of using this material in orthopedic implants is under study at the University of Illinois. As part of this program, plugs 1/8 in. in diam were inserted in holes drilled in the proximal femur of 2 groups of 8-week old male rabbits. The groups were sacrificed at the end of 1 and 2 years. A single i.m. injection of achromycin was given 2 days prior to sacrifice. Thin sections of the plugs and surrounding tissue were examined by microradiography and optical microscopy (white light, polarizing, and fluorescent). All bone was normal. Minimal evidence of irritation or fibrous encapsulation appeared.
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  • 11
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    Journal of Biomedical Materials Research 9 (1975), S. 105-117 
    ISSN: 0021-9304
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine , Technology
    Notes: A proposed specification covering handling characteristics and physical and chemical properties of bone cement composed primarily of methyl methacrylate has been prepared on the basis of data from the authors' studies and from various other sources. Under handling characteristics, requirements included relate to dough, handling and setting time, proper plasticity for insertion and temperature rise on setting. Mechanical properties specified include compressive strength and indentation and recovery characteristics. Maximum limits are proposed for water sorption and solubility. Suggested packaging requirements are also included.
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  • 12
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    Journal of Biomedical Materials Research 9 (1975), S. 149-155 
    ISSN: 0021-9304
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine , Technology
    Notes: Double-loop tendons of fixed and adjustable lengths, and tendons with inner porous tapes both for anastomosis to tendon stumps have been made from readily available materials. By using stainless steel wire and polymer fibers, breakloads have been obtained that range from 20 to 100 lb and elongations have been reduced to less than 2%. Pore sizes up to 50 × 250 μ2 were achieved by using woven, knitted, and braided polyester tapes. For all tendons, Silastic was used to isolate inner fibers and to effect smooth gliding. Preliminary evaluation of these devices, after being implanted in the feet of chickens for 4 weeks, indicates that anastomotic strength of unions formed by use of loops is about 1000 g compared to more than 2000 for unions formed by tissue ingrowth.
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  • 13
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    Journal of Biomedical Materials Research 9 (1975), S. 189-198 
    ISSN: 0021-9304
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine , Technology
    Notes: This investigation attempts to apply the concept of direct sketal attachment via tissue ingrowth to the attachment of femoral head prosthess to the femur. Stainless steel (316L) canine femoral head prostheses with a ceramic coated stem were implanted into the femora of dogs and their results compared to those obtained by the impaction of stainless steel prostheses and acrylic-stabilized prostheses. The implants were tested in vivo for time periods ranging from 2 to 13 months, after which time the animals were sacrificed and the femora excised. The femora were sectioned with the implants in place and prepared for examination by light microscopy. Bone was in closer approximation to the ceramic coated implants than to the other two types of implantations. The uncoated and acrylic-stabilized implants were usually charaterized by the presence of a relatively thick fibrous sequestering membrane.
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  • 14
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    Journal of Biomedical Materials Research 9 (1975), S. 79-95 
    ISSN: 0021-9304
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine , Technology
    Notes: The study of collagen fibers by X-ray diffraction, utilizing semiquantitative indices for appraisal of “structuration” and “orientation” was applied to 30 aortic valve grafts. These grafts, of pig origin, were studied in the fresh state, after tanning with aldehydes, and after having been implanted in patients for at least 18 months. It was shown that the collagen fibers are preferentially orientated parallel to the transverse axis of the valve cusps, and that this arrangement, enhanced by tanning, had a tendency to disappear in the post-implantation samples. The structuration index which concerns the fibril network was also augmented by tanning, and was found a little high or slightly diminished in post-implantation cusps. Evidence for a new compound, probably fibrin, was found in the diffraction patterns of implanted cusps, but crystallized calcium was noticeably absent.
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  • 15
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    Journal of Biomedical Materials Research 9 (1975) 
    ISSN: 0021-9304
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
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  • 16
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    Journal of Biomedical Materials Research 9 (1975), S. 197-205 
    ISSN: 0021-9304
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine , Technology
    Notes: Substitution of gold in part for silver in Ag3Sn alloys is found to result in two separate phases: γ (Ag3Sn particles) grains with a uniform distribution of gold within the grain and an Au—Sn phase in a form of ring surrounding the γ grain. The thickness of this ring increases with increasing gold concentration. The phases were identified by using the techniques of x-ray diffraction, optical metallography, scanning electron microscopy, and x-ray energy dispersive spectroscopy.
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  • 17
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    Journal of Biomedical Materials Research 9 (1975), S. 157-165 
    ISSN: 0021-9304
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine , Technology
    Notes: Historically, the surgical repair of serious injuries to the flexor tendons of the hand have met with loss than satisfactory clinical results. In an attempt to solve this problem, studies have been made on the design and testing of a Dacron polyester tendon prosthesis for complete replacement of the digital flexor tendon.The prosthesis attaches proximally at the anatomical musculotendon junction via collagen ingrowth into a fabric structure and in a similar manner distally via bone ingrowth at the anatomical insertion site. These fabrics are continuous with the tendon body of the prosthesis consisting of an inextensible braided cord which is silicone rubber coated to prevent tissue adherence in the glide zone of the tendon bed. An added benefit of the prosthesis is a simple means of length adjustment which can easily be carried out on the operating table.Studies have been performed in both dogs and chickens which indicate that sufficient tissue ingrowth occurs at both the distal and proximal anastomoses for retention of full load bearing capability in these animals and that postoperative adhesions are negligible, if present at all.Full prostheses have been implanted in dogs for periods of over 1 year and in chickens for 2 months. The chicken is the preferred animal model as a tendency for extensive scar tissue generation was shown in the dog.Both in vivo mechanical testing and histological characterizations have been made on sacrificed animals which have received the full prostheses.
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  • 18
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    Journal of Biomedical Materials Research 9 (1975), S. 199-219 
    ISSN: 0021-9304
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine , Technology
    Notes: A survey is given of the mechanical failures of the femoral component of Charnley and Charnley-Müller type total hip prostheses. Fractographic analysis reveals that all the prostheses have broken by metal fatigue.A review of the clinical data has been combined with a metallurgical and a mechanical study in order to assess the reasons of the mechanical failures.The following conclusions have been reached. The prosthesis should be inserted in varus position with regard to the axis of the intramedullary canal, and the prosthesis should be made of an alloy with appreciably higher yield stress and fatigue strength than the alloys of the investigated broken Charnley and Charnley-Müller type prostheses.
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  • 19
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    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 9 (1975) 
    ISSN: 0021-9304
    Keywords: Chemistry ; Polymer and Materials Science
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  • 20
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    Journal of Biomedical Materials Research 9 (1975), S. 423-439 
    ISSN: 0021-9304
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine , Technology
    Notes: Slow crack growth in Perspex acrylic sheet (PMMA) and Simplex acrylic bone cement in air and water has been studied from a fracture mechanics viewpoint. It has been found that the crack velocity, V, for each material depends upon the intensification of stress at the tip of the crack. Experimental measurements have been made of V as a function of the stress intensity factor, K, at the crack tip, and a derived V, K relationship has been used to predict the times-to-failure of components made from PMMA and Simplex cement. Direct measurements of time-to-failure for PMMA have shown that the predicted values give a conservative estimate of the structural lifetime of the material.
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  • 21
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    Journal of Biomedical Materials Research 9 (1975), S. 479-485 
    ISSN: 0021-9304
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine , Technology
    Notes: Because fluorocarbons can dissolve relatively large quantities of oxygen and carbon dioxide, there is considerable interest in utilizing them to develop new methods of extracorporael circulation, artificial red blood cells, and liquid breathing techniques. A method for the assay of fluorocarbon in blood is presented. The fluorocarbon is extracted from the blood with toluene, and fluoride is released from the fluorocarbon in the toluene extract by reaction with sodium biphenyl. The inorganic fluoride is then extracted with aqueous sodium acetate, the pH of the extract is adjusted, and the activity of the fluoride ion is read with a fluoride-specific ion electrode. The assay was effective for fluorocarbon concentrations in the range 1 to 30 ppm.
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  • 22
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    Journal of Biomedical Materials Research 9 (1975), S. 545-545 
    ISSN: 0021-9304
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
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  • 23
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    Journal of Biomedical Materials Research 9 (1975), S. 597-610 
    ISSN: 0021-9304
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine , Technology
    Notes: Defects were observed on the surfaces of various fine diameter wires commonly used in biomedical applications. These surface irregularities were viewed at high magnifications using a scanning electron microscope which has a much greater depth of field than normal light microscopy. Defects include scratches, pits, and crevices, which are the result of commercial wire drawing practices. Corrosion test results show that imperfections can serve as sites for localized corrosion attack which could lead to premature failures.
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  • 24
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    Journal of Biomedical Materials Research 9 (1975), S. 709-711 
    ISSN: 0021-9304
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
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  • 25
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    Journal of Biomedical Materials Research 9 (1975), S. 383-383 
    ISSN: 0021-9304
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
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  • 26
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    Journal of Biomedical Materials Research 9 (1975), S. 55-68 
    ISSN: 0021-9304
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine , Technology
    Notes: A number of carboxyl-containing ethylene copolymers have been prepared which exhibit long term antibacterial and antifungal properties. These materials, containing antimicrobial agents bound to the copolymer backbone as carboxylate salts, have been tested for their applicability to hospital products as a means of providing “self-sanitizing” articles. Tests have shown that these materials, although not bactericidal, do inhibit microbial growth. Investigations of the compatibility of these polymers with commodity polymers have been made and water emulsions of the polymers have been tested for applicability as components of product protectant coatings.
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  • 27
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    Journal of Biomedical Materials Research 9 (1975), S. 97-108 
    ISSN: 0021-9304
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine , Technology
    Notes: A study has been carried out on the structure and surface texture of a new dental implant material composed of vitreous carbon balloons (3 wt % or 6 wt %) and poly(methyl methacrylate). Tooth replica implants using this material had been successfully placed in baboons, and histologic study revealed normal alveolar bone and a peri-implant membrane with the connective tissue fibers oriented in a horizontal direction. Square wafers (10 mm × 10 mm × 1 mm) were studied, with the surface sandblasted in one-half of the specimens. Light microscopy revealed that in the 3% carbon specimens, the vitreous carbon microballoons were evenly spaced and often appeared to be fragmented within their spaces. S.E.M. studies revealed a finely porous surface with numerous large craters. Microballons were often seen within the craters in the nonsandblasted specimens.
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  • 28
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    Journal of Biomedical Materials Research 9 (1975), S. i 
    ISSN: 0021-9304
    Keywords: Chemistry ; Polymer and Materials Science
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  • 29
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    Journal of Biomedical Materials Research 9 (1975), S. 169-182 
    ISSN: 0021-9304
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine , Technology
    Notes: Specimens of beef bone were analyzed for thermal conductivity and thermal capacity. The thermal conductivity was about 7 × 10-4 cal/cm/sec/°C, that is about the same as for other tissues. As regards thermal capacity, the determination of 0.73 cal/cm2/°C also was similar to that in other tissues Both thermal conductivity and capacity were isotropic with respect to the layer of epiphyseal cartilage, and the orientation of bony trabeculae.Thermal probes were devised heated either by water or by electric current to destroy localized volumes of bone, as in surgery. To achieve necrotizing temperatures, the sizes of such probes and the times of application of heat were determined.
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    Journal of Biomedical Materials Research 9 (1975), S. 367-369 
    ISSN: 0021-9304
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine , Technology
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  • 31
    ISSN: 0021-9304
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
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  • 32
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    Journal of Biomedical Materials Research 9 (1975), S. 9-16 
    ISSN: 0021-9304
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine , Technology
    Notes: A written protocol for the investigation of candidate surgical implant materials is quite important. Biomaterials science sections of clinical protocols have been developed for porous alumina ceramic and nonporous vitreous carbon biomaterials.Published data on the properties of the biomaterials were evaluated as related to bone replacement and augmentation. Where necessary, limited laboratory studies were conducted. If decisions could not be reached with respect to a given application, animal studies were initiated. The surgeons worked with biomaterials in the laboratory and the biomaterials scientist attended the experimental surgery procedures.Biomaterials Science Laboratory nondestructive investigations including stereomicroscopic and x-ray inspections were conducted on the vitreous carbon dental implant systems. The investigations elucidated a number of unexpected features for both implant biomaterials and the overall interaction between the different disciplines resulted in a more complete protocol for the study of these biomaterials at our Medical and Dental Center.
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    Journal of Biomedical Materials Research 9 (1975), S. 623-628 
    ISSN: 0021-9304
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine , Technology
    Notes: The rate of in vitro enzymatic degradation of various materials based on collagen has been determined by a novel mechanochemical method, and has been compared with the extent of degradation resulting from subcutaneous implantation in guinea pigs. In vitro data correlate well with in vivo data. It is suggested that the simple in vitro method described is an effective means of screening a large number of materials based on collagen for their ability to resist degradation during implantation in animals.
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  • 34
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    Journal of Biomedical Materials Research 9 (1975), S. 661-674 
    ISSN: 0021-9304
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine , Technology
    Notes: Stress relaxation measurements were performed on thick-walled cylinders of radicular human dentin. The experimentally measured relaxation moduli were used to obtain an approximation to the logarithmic distribution functions of relaxation times. This distribution function was used to predict the behavior of other viscoelastic properties. In particular, the prediction of the strain and strain rate dependence of the modulus was determined and compared with experimental results.
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    Journal of Biomedical Materials Research 9 (1975), S. 119-131 
    ISSN: 0021-9304
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine , Technology
    Notes: The objective of this study was to develop a biodegradable material for use in reconstructive surgery of the bladder to serve a temporary function until normal regrowth of the host's tissue is completed. The biodegradable material can serve as a base over which the new bladder can regenerate. At the conclusion of the regrowth of the new tissue, the temporary material could be consumed by the body and therefore not have to be removed.Material evaluation showed that 70% acetic anhydride treated bovine pericardium was digested and dissolved in 4 weeks when implanted subcutaneously in dogs. Based upon this, supplementation of the bladder using this material was performed on 5 dogs. One dog showed urinary leakage and was sacrificed after 1 week. In 3 dogs examined 4, 6, and 48 weeks after implantation, respectively, the implanted material had been dissolved. In one animal autopsied at 10.5 months, a small remnant of the material still remained. Postoperative observation of the animals, excretory pyelocystograms and cystometry confirmed that the material applied was useful for experimental urinary bladder supplementation.
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    Keywords: Chemistry ; Polymer and Materials Science
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    Notes: The reaction between liquid mercury and Ag3Sn was studied at room temperature using a new type of specimen; i.e. bulk Ag3Sn electroplated with mercury. The surface morphology of the specimen and the phases formed on the Ag3Sn substrate were investigated by various techniques including optical microscopy, electron (scanning) microscopy, electron microprobe analysis, and electron diffraction. It was found that the mode of formation and type of crystalline phase appearing on the Ag3Sn specimen depended on the amount of mercury available. When the amount of mercury exceeded a certain quantity (about 1 mg/cm2) only the γ1 and γ2 phases were formed. On the other hand, when the amount of mercury was reduced below a certain low value (less than 0.3 mg/cm2), another silver-mercury phase, β1, formed as tiny “liquid-like” drops. The experimental technique employed in the present investigation has proved to be an excellent method for studying the reaction between liquid mercury and metal specimens. This new procedure may be employed to evaluate the amalgamation ability of potential new alloy systems.
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  • 37
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    Journal of Biomedical Materials Research 9 (1975), S. 273-283 
    ISSN: 0021-9304
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine , Technology
    Notes: The level of residual ethylene oxide after sterilization was evaluated as a function of aeration time for three medical grade tubings. Toxicity resulting from residual ethylene oxide was determined in an in vitro tissue culture system utilizing L-cells. The absorption and desorption of ethylene oxide from poly(vinylchloride) and polyether-polyurethane tubing were similar. In contrast, silicone tubing absorbed 85% less ethylene oxide. The time required for desorption of residual ethylene oxide was 2 hr for silicone tubing and 7 to 8 hr for poly(vinylchloride) and polyether-polyurethane tubing. Tubing samples containing 1,500 ppm or more residual ethylene oxide elicited toxic tissue culture reactions whereas samples containing 900 ppm or less showed no toxic tissue culture response.
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  • 38
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    Keywords: Chemistry ; Polymer and Materials Science
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    Notes: A segmented polyether urethane was used as the blood contacting surface in a series of 10 heart assist devices implanted in calves for periods up to 35 weeks. At termination, each was examined to correlate blood compatibility and device performance with surface properties, chemical purity, physical stability and affinity for lipid absorption.
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  • 39
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    Journal of Biomedical Materials Research 9 (1975), S. 63-66 
    ISSN: 0021-9304
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine , Technology
    Notes: Aging studies were done on calcia stabilized zirconia rods of 72% theoretical density to determine the effect of actual and simulated biological environments on their strength. They were aged without stress in vitro in Ringer's solution for 1, 2 and 4 weeks or in vivo in rabbits for 12 weeks. Rods aged in vitro showed mean losses in bending strength of 16, 17 and 19% respectively after 1, 2 and 4 weeks of immersion, while those aged in vivo showed a mean loss of 25%. It was concluded that the material tested would be unsatisfactory as an orthopedic replacement because of the rapid decrease in strength which occurred when exposed to actual or simulated biological media.
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  • 40
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    Journal of Biomedical Materials Research 9 (1975), S. 561-568 
    ISSN: 0021-9304
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine , Technology
    Notes: Medical grade silicone rubber (MGSR) is composed of polydimethylsiloxane (PDMS) as well as silica filler, oxidation products from the curing process, and other components. In a test that excludes air-blood interfaces, PDMS radiation cured under nitrogen has a whole blood clotting time 22% longer than MGSR. Curing the PDMS under oxidizing conditions maintains a 10% prolongation, but addition of silica filler to the PDMS returns the clotting time to that of MGSR. Extracting MGSR with solvents other than water appreciably lowers the clotting time. These results indicate that “pure” PDMS has an intrinsically high thromboresistance. Thrombogenicity is increased by the use of silica filler and oxidizing cure, as in MGSR.
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  • 41
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    Journal of Biomedical Materials Research 9 (1975), S. 611-621 
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    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine , Technology
    Notes: The influence of both imposed anodic potential in Ringer's solution and surface finish on the fatigue lives of annealed 316 type stainless steel and annealed pure titanium were measured and statistically compared to fatigue data run in air. The applied potentials in simulated extracellular fluid approximated conditions existing within the body while also producing the types of surface defects actually found on removed long time implants within the time interval of the accelerated R. R. Moore fatigue tests. Differentiating tests were run at single levels of applied cyclic stress well above the endurance limits.In Ringer's solution, the fatigue life of the 316 stainless steel decreased with increasing applied potential, and at +500 mV was significantly shorter than when run in air. At each condition, the 316 stainless steel was independent of initial surface finish. In contrast, the fatigue life of titanium improved rapidly with increasingly fine surface finishes. Furthermore, compared to air, the application of +500 mV in Ringer's solution improved the life of the rough surface finished material and markedly increased the number of cycles to failure for the electropolished specimens.
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    Journal of Biomedical Materials Research 9 (1975), S. 675-685 
    ISSN: 0021-9304
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine , Technology
    Notes: Between 1964 and 1970 the authors implanted Hydron gel in 62 patients with nose malformations. The cosmetic defects most freqently operated on were the saddle, and scoliosis of the nasal dorsum. By the end of 1973,39 of the total number of cases were checked again. In two cases, the gel had to be removed shortly after the operation because of local inflammatory changes. No signs of hypersensitivity could be detected. Calcifications were detected by x-ray examination in 54.2% of the cases. Thirty-four of the patients subjected to the checkup were satisfied with the results of their operations. The authors considered the results to be very good in 16 cases, and unsatisfactory in 6 cases. Calcifications detected by x-ray examination did not affect the final cosmetic effect.None of the examined patients had any complaints in connection with longterm application of the gel. Hydron gel seems to be a suitable implant material in plastic operations of the nose.
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    Journal of Biomedical Materials Research 9 (1975), S. 1-25 
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    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
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    Notes: A colloidal silica-based substitute for the water added to dental porcelain has been developed which restricts rounding on firing and gives greater and indefinitely prolonged unfired biscuit strength. In conjunction with product evaluation, it has been found that both the modulus of rupture and the diametrical tensile strength of dental porcelains can be measured with a high degree of precision.
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    Journal of Biomedical Materials Research 9 (1975), S. 69-78 
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    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
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    Notes: Powdered, sterilized zinc polycarboxylate was implanted subcutaneously in 56 young hamsters and 54 mice, using equal numbers of each sex, with 24 sham operated hamsters and 26 mice as controls. The hamsters were sacrificed after 15 months and the mice after 12. Implant material was recovered from one of 42 surviving mice and from 16 of 43 surviving hamsters. Benign adenomas of the gut, thyroid, sebaceous glands and ovary were found in 3 experimental mice and in one control. Benign adrenal adenomas were found in 3 experimental hamsters and in one control. One control hamster developed a rhabdomyosarcoma in a limb. One experimental hamster developed a leiomyosarcoma in close relation to an implant.
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    Journal of Biomedical Materials Research 9 (1975), S. 111-120 
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    Keywords: Chemistry ; Polymer and Materials Science
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  • 46
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    Journal of Biomedical Materials Research 9 (1975), S. 23-27 
    ISSN: 0021-9304
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
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    Notes: By means of the newly developed Replamineform process, the unique pore microstructures found in the skeletal calcium carbonate of certain reef corals can be replicated or reproduced with high precision in a wide variety of materials suitable for hard tissue implant and prosthetic applications. The advantages of fabricating porous biomaterials with this method include closely controlled size of both the pore diameters and the diameters of the pore interconnections, and virtually complete interconnection of the uniformly spaced pores. These properties are of great importance in implant devices, because tissue ingrowth, the stimulation of new bone formation, the suppression of undersirable scar tissue, the inhibition of adverse body responses, and firm biological fixation of the implanted material all depend upon the nature of the pore-microstructure configuration. Replamineform preparation of Al2O3, TiO2, hydroxyapatite, silver, Co-Cr-Mo alloys, and polymers is described in detail, and the characterization procedures used to determine the physical and structural properties of their materials are discussed. A few of the routinely measured characteristics include (1) quantitative computerized SEM image analysis for determining the volume, size and shape distributions of the macro and microporosity and the grain size measurement of the solid: (2) nondestructive x-radiography of specimens to reveal any internal defects; (3) mechanical strength measurements of randomly selected specimens. Experimental results up to now clearly demonstrate the superiority of microstructures imparted to metals, ceramics, and polymers with the Replamineform process.
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    Journal of Biomedical Materials Research 9 (1975), S. 29-45 
    ISSN: 0021-9304
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine , Technology
    Notes: The Replamineform process, a new technique for the fabrication of porous hard tissue implant materials which replicates the skeletal configuration of certain marine invertebrates, was used to manufacture 1 cm long by 0.5 cm diam cylinders. The inherent advantages of porous configurations obtained through this process are controlled, uniform pore size controlled pore-microstructure ratio, and complete interconnection of pores. The specific materials studied were chrome-cobalt-molybedenum alloy, αAlO3, hydroxyapatite prepared by hydrothermal conversion, and the basic (aragonite) CaCO3 skeleton of the coral genus Porities. The implants were placed in the cancellous bone of the distal femora and proximal tibiae of adult, mongrel dogs and analyzed at 8 weeks for tissue response and ingrowth. Uniformly, new bone was found to grow into the pores of these materials and become normally mineralized. These findings were determined by microradiography, scanning electron microscopy, electron microprobe analysis, and histology. No evidences of infection, rejection, or encapsulation were seen. In the case of those CaCO3 implants left in place for 1 year, there was almost complete resorption of the cylinders, with both bony trabeculae and unmineralized collagen (presumably osteoid) found at the sites of insertion.
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    Journal of Biomedical Materials Research 9 (1975), S. 73-80 
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    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
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    Notes: Disk-shaped implants of spinel, alumina, mullite, zircon, a cast Co-Cr-Mo alloy, and ultra-high molecular weight polyethylene (UHMWPE), were implanted in the paraspinalis muscle of 12 adult, male, white New Zealand rabbits. Prior to implantation the implants were characterized with respect to size and shape, weight and surface roughness. After periods of 1 month, 2 months, and 4 months, the rabbits were sacrificed and the tissue specimens were retrieved with the implants still intact. Histological examination of the tissues surrounding the implants along with changes in the size and shape, weight, and surface roughness of the implants were used a criteria for evaluating these materials for implant purposes.No surface degradation of any of the materials was detected using scanning electron microscopy. Fibrous tissue seemed to adhere to the UHMWPE implants more than any other material used in this study. Large amounts of fibrous tissue were also found to adhere to the cast Co-Cr-Mo alloy implants.The histological results indicated that within the limits of this investigation, the biocompatibility of the ceramic materials used in this study compared favorably with the clinically used Co-Cr-Mo alloy implants and the UHMWPE implants.
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    Journal of Biomedical Materials Research 9 (1975), S. 133-148 
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    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
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    Notes: Previously, the use of dissimilar metals for the construction of surgical implants has been strongly discouraged because the combination of metals was likely to provoke more rapid corrosion of one metal. With the passive alloys that are in present and future application, however, a reconsideration of the use of dissimilar metals is required. Presently available electrochemical tests allow accurate prediction of safe and unsafe combinations of metals. The use of dissimilar metals would permit selection of the alloy of appropriate mechanical properties for each part of an implant and would allow improved corrosion resistance that certain alloys can convey to other alloys with which they are in contact.
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    Journal of Biomedical Materials Research 9 (1975), S. 167-176 
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    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
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    Notes: The six principal clinical considerations which influence the choice of materials for total joint replacements are given.The necessity for screening tests on potentially useful materials is stressed. These should be carried out on specimens which have been exposed to the sterilizing process, which will be used in clinical practice. The materials should also be investigated after immersion in a physiological solution - bovine serum; following implantation in a large animal.Useful tests are impact testing, and wear studies using pin-on-disk and journal and bush specimens.In the case of total joint replacements, equipment in which joint motions and loadings can be simulated can provide valuable information. The components should also be subject to fatigue testing.There is a need to develop agreed laboratory methods for testing of materials and implants and for the long term follow up of patients.
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    Journal of Biomedical Materials Research 9 (1975), S. 221-225 
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    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
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    Notes: Three resins which include poly (methyl methacrylate), surgical Simplex P, and ultrahigh molecular weight polyethylene were selected to be evaluated as candidate systems for a polymer based composite for hard tissue prosthesis. Characterization of the mechanical behavior of these polymers in different environments including in vitro and in vivo storage was accomplished. As a result, conclusions were made as to which material maintained the least amount of mechanical variance as influenced by environmental effects. In vivo studies of implanted materials provided for a study of soft tissue response to each material. Conclusions were then developed as to the varying degrees of tissue reaction initiated by each material, and which resin generated the greatest tissue response with respect to the others.
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    Journal of Biomedical Materials Research 9 (1975), S. 243-249 
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    Keywords: Chemistry ; Polymer and Materials Science
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    Notes: The use of polyl (methyl methacrylate) for tooth replica implants, as developed by Hodosh, is described as to indications, ingredients, and fabrication technique. Laboratory testing of this material for mechanical and thermal expansion properties, and porosity content were determined as a function of foaming agent and anorganic bone particle content.
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    Journal of Biomedical Materials Research 9 (1975), S. 399-405 
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    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
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    Notes: At present, the smallest needle commonly available is about 130 μm in diameter in combination with a suture of about 25 μm in diameter. Marked reductions in size, particularly of the needle, are advantageous for microvascular surgery.A needle of about 70 μm in diameter, welded to a suture of about 18 μm diameter, has been developed. In initial tests, it has performed satisfactorily in the repair of the carotid artery of the white rat. It is shown that the basic properties of materials severely limit further reductions in the size of needles and sutures.
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    Journal of Biomedical Materials Research 9 (1975), S. 27-34 
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    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
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    Notes: Self-curing poweder-liquid admixed acrylic systems are used for internal fixation of total hip and total knee prostheses. Gel permeation chromatography revealed that the polymer chain length distributions of set cements were basically unaffected by their curing pressures. However, a decrease of approximately 11% in porosity coupled with a measured increase in mechanical strengths could be induced through the use of high curing pressures well beyond those attainable by the surgeon in the current arthroplasties. The conclusion of the investigation was that, to improve such cements, attention should be focused on elimination of porosity rather than attempting to produce higher degrees of polymerization.
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    Journal of Biomedical Materials Research 9 (1975), S. 109-110 
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    Journal of Biomedical Materials Research 9 (1975), S. 121-124 
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    Keywords: Chemistry ; Polymer and Materials Science
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    Journal of Biomedical Materials Research 9 (1975), S. 143-150 
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    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
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    Notes: The permeability of cellulose triacetate membrance coated activated charcoal is enhanced by treatment with KOH.The adsorption data for creatinine in aqueous solution before and after deacetylation are given. In order to study the usefulness of hemoperfusion associated with dialysis for removal of uremic toxins, some experiments were performed on the adsorption by coated and deacetylated charcoal of molecules of various molecular weights (from 113 to 40,000).Although the adsorption capacity of uncoated charcoal was better, the coated material still shows good properties in the adsorption of glucagon (mol wt 3485).The results on in vitro experiments of vitamin B12 removal by coated charcoal cartridge and CDAK Model 3 dialyzer confirms the usefulness of adsorption technique toward medium molecular weight compounds.
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    Journal of Biomedical Materials Research 9 (1975), S. 151-167 
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    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
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    Notes: The measured tensile and fatigue strengths of wrought and heat-treated cobalt chromium-molybdenum-carbon alloys such as HS21 were found to be more than twice those of as cast alloys of the same composition. The resistance of wrought HS21 to crevice corrosion at metal-Teflon contacts in isotonic salt solution at 37°C was found to be considerably greater than that of cast HS21, wrought HS25, wrought MP35, or 316L stainless steel which are currently used for surgical implants. The increased crevice corrosion resistance and mechanical strength of wrought HS21 as compared to as cast HS21 was attributed to greater chemical and structural homogeneity as well as to finer grain size and distribution of secondary phases. Fabrication of shaped implants from wrought HS21 is possible by techniques currently used for the fabrication of industrial parts from other wrought cobalt-chromium base alloys.
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    Journal of Biomedical Materials Research 9 (1975), S. 213-219 
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    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
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    Notes: The setting reaction of Ag3Sn amalgams may be thought of as a liquid phase sintering problem in which the reactants seek to form products with the lowest thermodynamic potential. We discuss the thermodynamic and kinetic considerations of this reaction. The lowering of free energy has been given as the reason for the formation of the γ1, γ2, and β1 phases and a qualitative reaction coordinate diagram has been hypothesized. The barrier height for the formation of the β1 phase has been determined to be 137 kJ/mol.
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    Journal of Biomedical Materials Research 9 (1975), S. 233-242 
    ISSN: 0021-9304
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine , Technology
    Notes: The Polymer Expansion Implant System, which is a system for the substitution of missing dental roots in natural or surgical alveolus, has been developed by the author. The polymer used is poly (methyl methacrylate) (PMMA).A material is sought that has three of the basic physical and mechanical qualities of human dentine: low modulus of elasticity, thermal and electrical passiveness, and ideal porosity. In addition it should be resistant, easily worked, biocompatible, and of low cost. Of the biomedical polymers, PMMA has these qualities, and it can be used as a substitute for dental roots.The design of bodies to be implanted as substitutes for dental roots requires: anatomical measurements of the maxilla and sockets; methods of retention by the bone tissue; and methods of insertion.The formation of lamina dura around an implanted body is a reply of the organism to the forces acting on it and a demonstration of the good interaction of the porosity of the material, the peri-implant collagenous fibers and bone. X-rays that demonstrate the behavior of bone to a PMMA implant are shown.Numerous expansion implants have been performed during the last 4 years with clinical and x-ray proof of their success. Three clinical cases representing the classic applications are presented: (1) individual replacement, (2) intermediate abutment, and (3) free-end abutment.
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    Journal of Biomedical Materials Research 9 (1975), S. 257-262 
    ISSN: 0021-9304
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
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    Notes: The purpose of this study was to assess the addition of a ceramic coating upon a Vitallium implant to increase the implant's biologic acceptability in the oral environment. The mandibular premolar teeth in 9 adult beagle dogs were removed bilaterally and these areas allowed to heal for 6 weeks. Ceramic coating with either Al2O3 or ZrO2 was carried out by flame spray deposition upon Vitallium anchor implants (9 of each), and the implants placed into the 18 healed premolar areas. Clinical and radiographic evaluation was conducted by 2 independent investigators over a 32 week period. Implants which exhibited mobility greater than II on a scale of 0 to III, at intervals of one-half, were judged unsatisfactory. After 19 weeks, all 9 Al2O3 coated implants and 5 ZrO2 coated implants were rated unsatisfactory. After 32 weeks, 4 ZrO3 coated implants were in situ with 0 or I mobility. Radiographically the width of the peri-implant space increased in direct proportion to both time and mobility. Histologic sections demonstrated encapsulating dense fibrous connective tissue which was oriented parallel to both ZrO2 and Al2O3 implants. Results suggest the zirconia used is a superior ceramic coating to the alumina. Neither seemed to increase biologic acceptability over uncoated Vitallium implants.
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    Journal of Biomedical Materials Research 9 (1975), S. 407-422 
    ISSN: 0021-9304
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine , Technology
    Notes: The adhesion of radio-labeled chick embryo muscle cells to the surfaces of radiation grafted hydrogels and other polymeric materials was measured in vitro. The degree of adhesion was determined by measuring the percentage of cells which remained adherent to the surfaces after 180 min of contact time (plating efficiency). Plating efficiency was found to vary between 2 and 94% depending on the nature of the surface. Preadsorption of albumin, γ-globulin or fibrinogen markedly affected subsequent adhesion of cells. Radiation grafted poly(2-hydroxyethyl methacrylate) and poly(N-vinyl-2-pyrrolidone) hydrogels on silicone rubber demonstrated exceptionally low adhesiveness in this assay. The potential for using this cell adhesion assay as a general screening test for biomaterials is discussed.
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    Journal of Biomedical Materials Research 9 (1975), S. 465-477 
    ISSN: 0021-9304
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine , Technology
    Notes: A case of a failed total hip replacement consisting of a Vitallium hip socket and a stainless steel femoral head prosthesis is presented. The mixed-metal combination and inadequate design resulted in severe abrasive wear and fretting corrosion of the bearing surface, and the accumulation of stainless steel wear debris and corrosion products in the periarticular tissues was extensive.The tissue response was primarily fibrotic scarring with severe histiocytic and mild foreign body giant cell reaction. Despite the massive accumulation of wear debris and corrosion products, however, there was minimal chronic inflammation and no acute inflammation.
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    Journal of Biomedical Materials Research 9 (1975), S. 537-542 
    ISSN: 0021-9304
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
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    Journal of Biomedical Materials Research 9 (1975), S. 511-536 
    ISSN: 0021-9304
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
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    Notes: Borosilicate glass (G) and commercial poly(methyl methacrylate) (PMM) surfaces were examined at pH 7, monovalent ionic strength 0.14 and 22°C. Thrombin concentrations ranged from 6 × 10-9 to 5.2 × 10-8M. Decreases in thrombin concentration in 10 ml vessels were determined by clotting time assay. Adsorption to PMM vessels is small. These were examined to establish the validity of the method. For G-vessels, the terminations of initial rapid decreases, associated with adsorption equilibrium, are accounted for mainly by an average isotherm having an association constant of 1.8 × 107 1./mol. Adsorption equilibrium is accompanied by a slower rate of decrease consistent with the surface denaturation of 2.5%/min of adsorbed molecules.Molecules remaining adsorbed to the surfaces of 1 mm i.d. G-capillaries were examined using the sequence of thrombin adsorption, buffer washing for times tw, removal of buffer and introduction of a fibringen aliquot for determination of effective surface thrombin concentration by a capillary clotting time. Most adsorbed molecules (〈90%) essentially desorb within tw = 2 min, a second class (〉8%) desorb in tw ∼30 min, and members of additional classes are still present after tw = 1440 min. For all of the properties examined, there is a small variance between vessels taken at the same time from the same batch, and a larger variance between groups of vessels taken at different times from the same batch or from different batches.
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    Journal of Biomedical Materials Research 9 (1975), S. 569-596 
    ISSN: 0021-9304
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine , Technology
    Notes: A series of poly(methyl methacrylate) formulations differing widely in chemical and physical properties was employed for the evaluation of primary screening methods for the assessment of acute toxicity. Materials and USP extracts of materials were tested in parallel. Tissue culture, hemolysis, intradermal irritation, systemic toxicity, muscle implant and histopathologic responses were determined for each of 27 formulations. A determination of the nonvolatile methanol extractable components was carried out on each formulation. The formulations varied with respect to percent, w/w, methyl methacrylate, N,N-dimethyl-p-toluidine, stannous octoate, 3,4-diamino-toluene and, also, with respect to curing conditions. Volatile components, primarily methyl methacrylate, of three selected formulations were determined quantitatively by vacuum distillation and mass spectrographic analysis.Statistical analysis of the primary data indicated a significant correlation of residue weight (methanol extractable) with hemolytic activity (r = 0.93) and with the cumulative biological response (r = 0.9). Multiple linear regression analysis of residue weights with hemolysis and intradermal irriation responses gave the highest overall correlation (r = 0.96). Hemolytic activity and tissue culture responses were significantly correlated (r = 0.87). It was concluded that the observed variation of biological test results reflected significant differences in the toxicity of the test materials. The poly(methyl methacrylate) series examined was relatively low in toxicity and the biological tests examined, particularly the in vitro tests, were found to be responsive to formulation and curing conditions which indicated their suitability for primary toxicity screening.
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    Journal of Biomedical Materials Research 9 (1975), S. 645-659 
    ISSN: 0021-9304
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine , Technology
    Notes: A blend of Silastic 382 (Room Temperature Vulcanizing, RTV) Medical Grade silicone oil and a catalyst was prepared in vitro, in both the catalyzed and noncatalyzed state, and injected subcutaneously in mice, rats, and rabbits. When properly blended, this catalyzed material, referred to as “silicone gel,” formed a soft rubbery mass that remained at the site of injection. Properly catalyzed silicone rubber gel produces no macroscopic inflammatory reaction, attracts few polymorphonuclear leucocytes, and after 5-6 days a thin fibrous capsule begins to form around the gel. No degeneration of the silicone gel was observed during the 62 days of this experiment. Additional rats with this silicone gel have been under observation for 8 months and clinically have shown no changes in the local mass of silicone. If the catalyst is partly oxidized when added to the silicone fluid, the degree of gelling is much less. A local mass usually forms at the site of injection with some of the fluid diffusing into the tissue, forming minute cysts. The inflammatory reaction is characterized by polymorphonuclear leucocytes, associated with many macrophages and giant cells phagocytizing oil droplets and particles of the diatomaceous earth. The pathogenesis of the inflammatory reaction is discussed, referring to the ionic change and the emigration of polymorphonuclear leucocytes to particles of plastics embedded in tissue.
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    Journal of Biomedical Materials Research 9 (1975), S. 35-53 
    ISSN: 0021-9304
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine , Technology
    Notes: There is a continuing need for the complete characterization of the physica and chemical properties of dental materials. Among these properties is surface area. The problem is further complicated by the fact that most dental materials are, themselves, mixtures of two or more identifiable components. If the vapor adsorptive properties of these components are different in the mixture from that which would be expected of them collectively, then interaction is present. Interaction must not be confused with the lack of additivity which results from the limitations of the BET theory applied to mixtures. Equations are derived herein to estimate the extent of this latter source of variability and to correct for it giving a “true” surface area for the aggregate. Conversely, the adsorptive properties of either component can be calculated from the properties of the mixture and the remaining component together with the percentage composition. An immediate application can be made in determining the water-vapor adsorptive properties of human dentinal collagen without necessitating its removal from dentin. Any attempt to extract it chemically may produce denaturation or chain rupture thus precluding the possibility of direct determination. In the case of nitrogen adsorption, however, interaction definitely is indicated.
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    Journal of Biomedical Materials Research 9 (1975) 
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    Keywords: Chemistry ; Polymer and Materials Science
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    Journal of Biomedical Materials Research 9 (1975), S. 285-301 
    ISSN: 0021-9304
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine , Technology
    Notes: Modified collagen membrane when compared to autograft, homograft, heterograft and silicone polymer memberane, demonstrated a superior adherence on split and full-thickness surfaces, but proved to be an inferior covering for granulating surfaces. Water vapor transport was found to be adequate and adaptable to modification. It was found to be permeable to most commonly used topical antibiotics, and no significant antigenicity could be demonstrated. In a controlled animal burn study, modified collagen membrane proved superior to homograft and heterograft in regard to mortality, time to grafting, bacteriology and autograft take. These studies provide a background for further laboratory and clinical studies now in progress.
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    Journal of Biomedical Materials Research 9 (1975), S. 127-142 
    ISSN: 0021-9304
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
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    Notes: A thermodynamic approach to the problem of platelet adsorption out of a suspension on to a smooth and homogeneous solid surface is developed. The interfacial tension values required may be estimated from contact angle data by means of an equation of state relation. According to the thermodynamic approach the functional dependence of platelet adsorption on surface tension of the solid differs according to whether the surface tension of the platelets is smaller or larger than the surface tension of the liquid in which they are suspended. The implications of this thermodynamic approach in situations where plasma proteins are present and the biomaterials surfaces may be heterogeneous and rough are discussed. Previous analyses using the critical surface tension of wetting and other surface-related parameters are compared with the thermodynamic analysis given here.
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    Journal of Biomedical Materials Research 9 (1975), S. 183-195 
    ISSN: 0021-9304
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine , Technology
    Notes: Defects were created in the tooth-supporting bone of six beagle dogs. Biodegradable tricalcium phosphate was compared to cancellous marrow as a treatment method. The findings indicated that ankylosis and resorption of the tooth can occur when using marrow. The ceramic-filled defects healed slower; but the material itself was well tolerated by the tissues, initiated new bone formation, filled in the defect, and has good potential for the treatment of advanced periodontitis.
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    Journal of Biomedical Materials Research 9 (1975), S. 237-252 
    ISSN: 0021-9304
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine , Technology
    Notes: The finite element method used to study stress generated in a maxillary second premolar as a result of occlusal forces. This mathematical technique has been applied extensively in structural engineering and structural mechanics. It is well suited to the analysis of stress in teeth and dental restorations because it can closely simulate the geometries, loads, and material inhomogeneities in the system being studied.
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    Journal of Biomedical Materials Research 9 (1975), S. 253-254 
    ISSN: 0021-9304
    Keywords: Chemistry ; Polymer and Materials Science
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    Journal of Biomedical Materials Research 9 (1975), S. 259-264 
    ISSN: 0021-9304
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine , Technology
    Notes: Cyclic polarization curves obtained for a cobalt-base casting alloy (similar to Vitallium Surgical Alloy) and for 316L stainless steel show that the cobalt-base alloy exhibits a high (noble) protection potential whereas the stainless steel exhibits a low (active) protection potential. It is suggested that the resistance to crevice corrosion of Vitallium Surgical Alloy results from its high value of protection potential whereas the susceptibility of 316L stainless to severe crevice corrosion results from its low value of protection potential.
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    Journal of Biomedical Materials Research 9 (1975), S. 303-313 
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    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine , Technology
    Notes: A cobalt based alloy, MP35N, with excellent mechanical properties has been recently introduced as a material for surgical orthopedic implants.A study was made of local and systemic host response to this material in two different mammal species. The implantation time ranged from one to 12 months.The result of this study indicated: MP35N produces a degree of local tissue response comparable to that of 316L stainless steel. No sytemic side effects were observed during the implantation times included in this study.
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    Journal of Biomedical Materials Research 9 (1975), S. 355-366 
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    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine , Technology
    Notes: Implantable, sustained release drug delivery devices offer benefits not obtained through oral ingestion or injection. These include delivery at a constant therapeutic rate, thus avoiding adverse intermittent and massive dose effects, as well as reliance upon patients taking their prescribed dosages. The drawbacks to their widespread acceptance have been their inability to maintain a zero-order release rate over an extended period of time and poor biocompatibility. Devices capable of satisfying these requirements have been developed and tested extensively for in vitro release of the narcotic antagonist cyclazocine. By using implant models prepared from Hydron, a hydrophilic polymer known to exhibit excellent tissue compatibility, we have found that the release rate could be precisely regulated by proper geometry, copolymer composition, concentration of ionogenic groups and cross-link density. Devices in such varied forms as capusles, barrier-film coated tablets and bulk polymerized rods have been tested in vitro for periods approaching 1 year.
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    Journal of Biomedical Materials Research 9 (1975), S. 371-374 
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    Keywords: Chemistry ; Polymer and Materials Science
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    Journal of Biomedical Materials Research 9 (1975), S. i 
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    Journal of Biomedical Materials Research 9 (1975), S. v 
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    Keywords: Chemistry ; Polymer and Materials Science
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    Journal of Biomedical Materials Research 9 (1975), S. 47-61 
    ISSN: 0021-9304
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine , Technology
    Notes: A series of squirrel monkeys received segmental femoral replacements in a study of the strength of the interface developed between the implant and bone. Implants were either made completely of bioglass-ceramic, or 316L stainless steel with a flame-prayed coating of bioglass. Fracture torque, energy at fracture, and shear stress at failure were compared to values obtained from a control group of pairs of tibias. Femurs containing bulk bioglassceramic implants showed about a 25% difference in strength compared to the opposite bone, while femurs containing flame-sprayed implants exhibited extremely low structural strength. While the strength of the metal-glass bond was very low (〈500 kgf/cm2), the bonebioglass bond was found to be at least as strong as the bioglass-ceramic, and at least 3/4 as strong as the host bone.
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    Journal of Biomedical Materials Research 9 (1975), S. 89-98 
    ISSN: 0021-9304
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine , Technology
    Notes: For convenience in clinical manipulation, it is the practice to fabricate PMMA prostheses from mixtures of powder and monomer. When the monomer is subsequently polymerized an unusual 2-phase polymeric material results in which grains of PMMA are dispersed in a matrix of the same polymer.The mechanical properties of the 2-phase materials are inferior in certain respects relative to 1-phase polymers.The purpose of the present work is to evaluate the failure of 2-phase materials by microscopical examination of their fracture surfaces. A granular microstructure was clearly distinguishable and a distinction made between materials which fail exclusively by transgranular fracture and others which additionally exhibit intergranular fracture.In order to interpret markings observed on the fracture surfaces of the complex 2-phase systems a study was made of the influence of molecular weight on the fractography of 1-phase PMMA. Molecular weight was reduced by degradation of samples by exposure to γ-rays. The spacing of periodic rib markings on fracture surfaces was found to decrease with molecular weight and this relationship used to provide an estimate of the molecular weight of polymer in the matrix of 2-phase materials.
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    Journal of Biomedical Materials Research 9 (1975), S. 699-707 
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    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine , Technology
    Notes: Because of the unique properties for swelling in a fluid medium and variable modulus of elasticity, hydrophilic methacrylates may be of potential usefulness for implanting prosthetic devices in bone. To investigate the biocompatibility, electron micrographic studies were done on specimens of poly(2-hydroxyethyl methacrylate) imbedded in bone for varying periods of time. Ultrastructural examination revealed progressive ossification of surrounding connective tissue up to the tissue polymer junction over a 6 month period. There was no evidence of inflammatory response. Based upon this study, it would appear that bone adjusts to an implant of hydrophilic methacrylate by ossification to the implant junction. This supports continued studies into the usefulness of this material as an implant.
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    Notes: Four different acetabular replacement designs and 2 femoral head replacement designs made out of high density alumina ceramic have been tested in sheep with postoperative survival times of up to 11 months (Frialit 99: Al2O3 99.6%, MgO 0.4%).It can be concluded from these experiments that a cement free implantation technique with alumina requires a primary rigid fixation of the implant to bone, with the possibility for new bone growth along the ceramic and into grooves and macroscopic holes for further interdigitation. Three different solutions for the acetabular component can be recommended for human application.In addition, an all ceramic femoral prosthesis has been tested for bending strength in its neck region. Twenty prostheses have been fractured, all of which showed values for bending strength far higher than the physiological neck fracture level (900 kp/cm2). The present state of development of all ceramic prostheses is discussed. Up to now, the development of fibrous tissue between the bone and the ceramic implant has caused reservations with human implantation. The direct definite anchorage problem has to be resolved first.
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    Journal of Biomedical Materials Research 9 (1975), S. 227-232 
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    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine , Technology
    Notes: Various implants have been developed for the upper and lower extremities and the spine. In order to establish whether endoprostheses made of Al2O3 will show the same good biocompatibility in humans as it has in experiments with animals, endoprostheses implantations were performed in 4 patients: 2 upper arms, 1 radius, 1 vertebra body. The implants were exposed to various loads. The biomechanical conditions were considered in the construction. The results reveal that the knowledge of material properties and prior calculations make possible the development of satisfactory endoprostheses. X-ray examinations confirm these deductions. Good functionality was achieved in vivo with all implants. They were all mechanically anchored, no bone cement was used. Thus the biocompatibility of the material was not limited. A histological examination is made of one implant. The macroscopic examination showed a stable fit and no pathological reactions. X-rays revealed that the bone remained in good contact with the implant. The longest observation period was over 1 1/4 years. Present observations show that the use of Al2O3 implants, without the use of additional materials (bone cement), results in a tight fit of the implants.
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    Journal of Biomedical Materials Research 9 (1975), S. 251-255 
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    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine , Technology
    Notes: The present investigation is concerned with answering some of the questions which arise when discussing the success or failure of endosteal implants on the basis of the resulting stresses caused in the surrounding bone structure. In particular, the questions examined are: 1) What affects do variations in the mechanical properties of the implant, an encapsulating membrane and the surrounding bone, have on the stress distribution? 2) Are some implant designs more affected than others, as indicated through variation of bone properties? and 3) What is the affect of an encapsulating membrane and how does a change in its thickness affect the stress distribution? A similar study was conducted on a simulated tooth, so that a comparison may be made between implant and tooth related stress distributions. The method of analysis used to obtain answers to these questions is the finite element method.Results of the investigation show that for a fixed implant geometry, a change in implant properties causes only minor changes in the bone stress distribution. A change in the membrane and bone properties, however, has a greater affect on the resulting stress distribution. It is also shown that the presence of a protective membrane has a beneficial affect on the stress distribution in the surrounding bone structure and that an optimum thickness can be estimated. Finally, the results show that some implant designs create a situation which results in stronger dependence of stress upon the properties of the surrounding bone.
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    Notes: Previous work has shown that needles of γ2 crystals form when mercury is plated on the surface of an Ag3Sn specimen. In the present study, the growth kinetics of γ2 needles were investigated from room temperature to 50°C for varying amounts of plated mercury. Straight-line relationships between crystal length and the square root of the time of growth showed that the growth rate is diffusion controlled. The growth rate increased with temperature up to 40°C but decreased at higher temperatures. Further, as the temperature was increased, fewer γ2 crystals formed and their growth length decreased. This demonstrates that a number of competing factors are involved in the growth process at high temperatures.
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    Journal of Biomedical Materials Research 9 (1975), S. 441-451 
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    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
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    Notes: Ceramic pelletes (in Al2O3 92% and in calcium aluminate) implanted into the muscles of rabbits for varying periods of time, and samples of similar material, not implanted but mixed with organic substances, have been analyzed by means of thermal differential analysis (TDA).Which hydrated calcium aluminates are formed from implants after contact with the tissure fluid, has been established.It has also been ascertained that the ceramic implants absorb organic substances from the tissue fluid, which, from a first evaluation, seem to be composed of simple molecules.The results of this initial inquiry have provided positive indications of the utility of TDA to assist in elucidating the phenomena that occur between implant and tissue.
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    Journal of Biomedical Materials Research 9 (1975), S. 487-499 
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    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine , Technology
    Notes: Surface modification of cellulose acetate dialysis membranes was carried out by 60Co radiation induced graft copolymerization of the hydrogel, hydroxyethyl methacrylate (HEMA). The degree of grafting was controlled by varying the HEMA monomer concentration in the grafting solution and the radiation dose. A continuous flow platelet adhesion test was designed which allows testing under conditions more closely approximating hemodialysis than other small scale in vitro tests. Platelet adhesion on treated membranes fell substantially with increasing surface HEMA concentration. The presence of HEMA on the membrane surface did not affect the membrane activated clotting times significantly.
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    Journal of Biomedical Materials Research 9 (1975), S. 543-545 
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    Keywords: Chemistry ; Polymer and Materials Science
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    Journal of Biomedical Materials Research 9 (1975), S. 547-560 
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    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine , Technology
    Notes: Glow discharge treated (GDT) inorganic materials are sterile and free of all organic contaminants. Such materials implanted in the canine inferior vena cava often demonstrate significant thromboresistance. Standard Pyrex glass tubing was GDT in argon to provide a surface free energy above 70 dynes/cm, slight surface negativity, and other surface-physical modifications of its interface. Chromic acid cleaned lengths of the same tubing, and short segments whose edges were not fire-polished were used as controls. Upon canine implantation, the in vivo results were similar in independent surgical laboratories. The glass was implanted as 1.4 cm long rings or as 5 cm long tubes in separate medical centers according to different protocols. GDT specimens remained patent; all controls accumulated thrombi. A remarkably pure, low critical surface tension, labile protein coating covered all cylindrical lumens after 2 hr in vivo. This coating diminished within 2 weeks and was essentially absent after 480 days, even though scanning EM showed evidence of a micron thick luminal film, probably eroding glass. No emboli were found in the implant animal's kidney or lungs at any stage.
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    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine , Technology
    Notes: Plasma coating (deposition of polymer under the influence of plasma) is utilized to modify the surface properties of corneal contact lens. An ultrathin layer (thickness of roughly 200 Å) of plasma polymer of acetylene/H2O/N2 is applied to poly(methyl methacrylate) (PMMA) corneal contact lenses. The surface becomes highly wettable with water compared to uncoated lens. When coated and uncoated contact lenses are placed on rabbit eyes, a remarkable difference in accumulation of mucous matter is observed. With the control lenses, the accumulation of mucous matter in a week is sufficient to affect the optical clarity of the lenses, whereas the coated lenses show no change after three months continuous wearing. The comparative degree of adhesion of the corneal epithelium cells onto glass, modified glass, PMMA, and coated PMMA surfaces is studied using tissue cultures and phase contrast microscopy. The coated PMMA surface exhibits a degree of tissue adhesion lower than that of control PMMA and higher than that of glass surface, and no sign of toxicity of the coated surface is observed by the tissue cultures.
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    Journal of Biomedical Materials Research 9 (1975), S. 687-697 
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    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine , Technology
    Notes: Aqueous extracts of a PVC transfusion tubing contracted isolated guiea-pig ilea. A pharmacological and chemical study (infrared spectroscopy, gas-liquid chromatography) showed that this was due to extration of the plasticizer, acetyl N-tributyl citrate (ATBC). The concentrations of ATBC to produce contractions of the isolated guinea-pig ileum (from 1 μg/ml) can be compared with those achieved after recirculating tubing under conditions simuflating use (up to 6 μg/ml).In assenssing the toxicity of plastic tubing, there is a need to determine extraction of constituents under conditions simulating use and the effects of such extracts on a cariety of tissues.
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    Journal of Biomedical Materials Research 9 (1975), S. 263-269 
    ISSN: 0021-9304
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine , Technology
    Notes: There are three distinct regions with which a wedge shaped dental implant is in contact; the intraoral, transitional and intraosseous portions. The environment of each of these is different and will require special consideration.This investigation compares the epithelium found associated with a natural tooth to that which is found contiguous with the transitional region of an implant.The possibility of a pseudojunctional epithelium being formed in association with a glass collar processed onto the neck of a wedge shaped implant is examined. The histological appearance of a specimen in situ for 11 months shows an altered epithelial structure compared to that found adjacent to the neck of an unmodified titanium wedge shaped implant. Because the implant and glass must be mechanically separated from the tissue being examined, the value of demeneratized histological sections is limited.However, examination by a Scanning Electron Microscope of the surface of the glass after removal reveals an area of clear glass in the deeper region of the collar. Above this there is a deposit, the exact nature of which is unknown, but which might be interpreted as the contents of the gingival crevice.Although this might be interpreted as a type of epithelial attachment, other factors are necessary to ensure close gingival adaptation and limitation on epithelial downgrowth.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
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  • 95
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    Electronic Resource
    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 9 (1975), S. 387-387 
    ISSN: 0021-9304
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine , Technology
    Type of Medium: Electronic Resource
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  • 96
    Electronic Resource
    Electronic Resource
    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 9 (1975) 
    ISSN: 0021-9304
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine , Technology
    Type of Medium: Electronic Resource
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  • 97
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    Electronic Resource
    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 9 (1975), S. 341-353 
    ISSN: 0021-9304
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine , Technology
    Notes: Wear testing should be an important part of the investigations into the physical and mechanical properties of some dental materials. It has, however, largely been ignored because of conflicting and unreproducible results. It was decided, therefore, to review the work done by other researchers and to examine the human masticatory cycle, and then present new parameters to design and construct a new dental abrasion testing machine. This new machine is described in detail and its capabilities briefly illustrated.
    Additional Material: 7 Ill.
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  • 98
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    Electronic Resource
    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 9 (1975), S. 375-380 
    ISSN: 0021-9304
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine , Technology
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
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  • 99
    Electronic Resource
    Electronic Resource
    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 9 (1975) 
    ISSN: 0021-9304
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine , Technology
    Type of Medium: Electronic Resource
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  • 100
    Electronic Resource
    Electronic Resource
    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 9 (1975), S. 17-22 
    ISSN: 0021-9304
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine , Technology
    Notes: Sixteen ceramic specimens were implanted in the femur of mature rhesus monkeys. The specimens consisted of four groups of a basic calcium aluminate composition with additions of 5, 10, 15 and 20 wt% phosphorous pentoxide (P2O5). The increasing amounts of P2O5 caused variations in the resorption rate, microstructure and surface characteristics of the implant. The influence of these variables on bone and tissue growth within and about the implant was investigated.After sacrifice the ceramic-bone specimens were studied by a tetracycline-based histological analysis, scanning electron microscopy and energy dispersive analysis.The results indicate an increase in mesenchymal cell proliferation, fibrous and bone tissue formation at the ceramic tissue interface and within the implant with increasing concentrations of P2O5.The results obtained from the study did not furnish sufficient evidence to differentiate between the direct chemical influence the increasing P2O5 had on osseous tissue formation or the indirect influence that may have resulted from its effect on the ceramic microstructure and morphology.
    Type of Medium: Electronic Resource
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