Bio-Medical Materials and Engineering - Volume 1, issue 1

Authors: Yokobori, Takeo

Article Type: Other

DOI: 10.3233/BME-1991-1101

Citation: Bio-Medical Materials and Engineering, vol. 1, no. 1, pp. 1-1, 1991

Authors: Miyasaka, Yoshinori | Sakurai, Minoru | Yokobori, Jr., A. Toshimitsu | Kuroda, Sumio | Ohyama, Masamizu

Article Type: Research Article

Abstract: Long bone injuries in clinical cases are studied by comparison of roentgenograms with a rational mechanical analysis of the injuries. Fractures produced by torsional loads have a spiral shape with a smooth and even surface. Fractures induced by bending loads have uneven and rugged fracture surfaces perpendicular to the bone axis. Long bones are weak in torsion but strong in tensile stress produced by bending. This result corresponds to the clinical fact that a large direct external force is needed to produce a transverse fracture while a spiral fracture is produced by a relatively small torque.

Keywords: long bone injuries, transverse fracture, spiral fracture

DOI: 10.3233/BME-1991-1102

Citation: Bio-Medical Materials and Engineering, vol. 1, no. 1, pp. 3-10, 1991

Authors: Okayama, Shin | Akao, Masaru | Nakamura, Satoshi | Shin, Yoshiharu | Higashikata, Masaaki | Aoki, Hideki

Article Type: Research Article

Abstract: The mechanical properties and solubility of sintered Sr-substituted hydroxyapatites were examined in order to investigate the influences of Sr incorporation into hydroxyapatite in bones and teeth on them. Hydroxyapatite (HAp), Sr-substituted hydroxyapatite (Ca.SrAp), and strontium-hydroxyapatite (SrAp) were synthesized and sintered. The bending strength and Young's modulus were measured. Also, solubility in isotonic NaCl solution was examined. The Young's modulus of Sr-substituted hydroxyapatite (Sr wt% = 1.0) and hydroxyapatite surface treated with Sr ion were greater than that of hydroxyapatite. The bending strengths of Sr-substituted hydroxyapatites (Sr/Ca=4/6 and less) were reduced slightly compared to that of hydroxyapatite. The bending strength of …hydroxyapatite surface treated with Sr ion was increased compared to that of hydroxyapatite. The solubility in isotonic NaCl solution at 37°C was increased with an increase in Sr content. The effects of Sr on the mechanical properties and solubility of bones and/or teeth are discussed. Show more

Keywords: bioceramics, sintered strontium-substituted hydroxyapatite, mechanical property, solubility

DOI: 10.3233/BME-1991-1103

Citation: Bio-Medical Materials and Engineering, vol. 1, no. 1, pp. 11-17, 1991

Authors: Lees, Caroline | Vincent, Julian F. V. | Hillerton, J. Eric

Article Type: Research Article

Abstract: Poisson's ratio of cow teat skin was measured uni- and biaxially and shown to be anisotropic and dependent on aspect ratio. At strains below 0.1 (where Cauchy and Hencky strain are indistinguishable) the Poisson's ratio of cow teat skin measured biaxially is very much greater than 1.0, whereas the Poisson's ratio of distending artery is between 0.5 and 0.3. Knitted fabric behaves similarly to cow teat skin in that it can give a negative Poisson's ratio at low strains. Skin is therefore probably to be considered mechanically as an open feltwork of fibres rather than some sort of continuum.

Keywords: Poisson's ratio, skin, anisotropy, fibrous network

DOI: 10.3233/BME-1991-1104

Citation: Bio-Medical Materials and Engineering, vol. 1, no. 1, pp. 19-23, 1991

Authors: Yokobori, Jr., A. Toshimitsu | Yokobori, Takeo

Article Type: Research Article

Abstract: Mechanical testing methods were developed by us using the pulsatile internal pressure through-flow system. The methods were applied to estimate the permeability and fatigue strength of a vascular substitute, the mechanical behaviour of anastomosed site between vascular substitute and blood vessel, and the mechanical behaviour of the blood vessel itself. A testing method is also proposed for puncturing a vascular substitute which is used as blood access for hemodialysis. The mechanical behaviour of punctured vascular substitute and the puncturing technique itself are investigated. The fatigue-creep testing method of cellophane membrane is also reported to estimate the durability of cellophane membrane …by using the circulating pulsatile internal pressure through-flow system. The mechanical testing method for visco-elastic characteristic of biomaterials is discussed. Show more

Keywords: mechanical test method, cardiovascular grafts, cellophane membrane, cellophane tube, blood vessel, pulsatile internal pressure through-flow system, fatigue test, permeability test, puncturing test, hemodialysis

DOI: 10.3233/BME-1991-1105

Citation: Bio-Medical Materials and Engineering, vol. 1, no. 1, pp. 25-43, 1991

Authors: Kim, Kyo-han | Park, Jin-hoon | Imai, Yohji | Kishi, Teruo

Article Type: Research Article

Abstract: Fracture toughness (KIC ) critical stress intensity factor, and bending strength of 3 types of commercially available dental composite resins (macrofilled. hybrid and microfilled type) were determined using three point bend specimens. Acoustic Emission (AE), which is the generation of elastic wave due to the release of energy from the localized sources in material. was also detected during the fracture toughness test. Fracture surfaces were examined by scanning electron microscope. The fracture toughness values, AE patterns, and the nature of fracture surface were analyzed to understand fracture behavior of dental composite resins and fracture mechanism for each dental composite resin …are proposed. Show more

Keywords: fracture toughness, bending strength, acoustic emission, dental composite resin, fracture behavior

DOI: 10.3233/BME-1991-1106

Citation: Bio-Medical Materials and Engineering, vol. 1, no. 1, pp. 45-57, 1991

Authors: McMillin, Carl R.

Article Type: Research Article

Abstract: A step increasing strain accelerated fatigue test has been developed and validated for the evaluation of candidate elastomeric materials for the artificial heart program. Whereas standard fatigue tests can be approximated by a log-normal or Weibull distribution, the increasing strain accelerated fatigue test has the general appearance of being normally distributed (i.e., a Gaussian distribution). The hypothesis that the data is indeed normally distributed was examined using a variety of statistical tests. The mean and median were equivalent in all data sets compared, as they would be for normally distributed data. There was very little positive or negative skew found …in data collected under a wide variety of conditions. The data was found to have a slightly stronger than expected central tendency (positive kunosis), but most of this disappeared when the data were normalized. Chi-squared analysis found normally distributed data in most subset of the data except for those with small numbers of test specimens per test. Normalized test data was not found to differ significantly from a Gaussian distribution by the Kolmogorov-Smimov test. It therefore appears that increasing strain accelerated fatigue test data can be approximated by a normal distribution. This allows for easy data interpretation and aids in the extrapolation of incomplete data sets. Show more

Keywords: accelerated fatigue tests, elastomers, rubbers, statistical analysis, strain

DOI: 10.3233/BME-1991-1107

Citation: Bio-Medical Materials and Engineering, vol. 1, no. 1, pp. 59-74, 1991