Bio-Medical Materials and Engineering - Volume 2, issue 2

Authors: Oshida, Yoshiki | Sachdeva, Rohit C. L. | Miyazaku, Shuichi

Article Type: Research Article

Abstract: Orthodontic archwires (equiatomic TiNi alloy) of both used (4 weeks) and unused conditions were microanalyzed by optical and scanning electron microscopes, energy dispersive X-ray spectroscopy, and electron diffraction to characterize the surface layers. They were also subjected to immersion and polarization corrosion tests in a 0.9% NaCI aqueous solution. Based on results obtained from these analytical and experimental studies, surfaces of TiNi archwires were further electrochemically treated to etch away nickel selectively and reform the surface morphology to uniform and porous surface layers. Main conclusions were: (a) surface layers of used archwires were covered contaminants causing the discoloration, and the …contaminants were identified as mainly KCl crystals, (b) surfaces of both used and unused wires were observed to be inegular features characterized by lengthy island-like structures, where nickel was selectively dissolved, (c) corrosion tests in a 0.9% NaCl aqueous solution in immersion and polarization methods indicated that by increasing temperature from 3°to 60°C and acidity from pH 11 to pH 3, calculated corrosion rates increased, and (d) surface layers of TiNi archwires can be electrochemically modified to selectively etch nickel away, leaving a Ti-enriched surface layer and forming a uniformly distributed porous surface that may reduce the coefficient of friction against the orthodontic brackets. Show more

Keywords: superelasticity, shape memory effect, TiNi alloys, corrosion rate, nickel dissolution, nickel toxicity, hypersensitivity, polarization, porous surface, biocompatibility

DOI: 10.3233/BME-1992-2201

Citation: Bio-Medical Materials and Engineering, vol. 2, no. 2, pp. 51-69, 1992

Authors: Tomita, Naohide | Tamai, Susumu | Shimaya, Masataka | Mii, Yoshio | Ikeuchi, Ken | Ikada, Yoshito

Article Type: Research Article

Abstract: The tension holding capacity of suture materials was measured by in vitro and in vivo experiments. Silk and expanded polytetrafluoroethylene sutures showed large elongation and significant knot slacking after tight tying. Although ultrahigh molecular-weight polyethylene suture had excellent creep resistance, it showed a relatively low tension holding capacity because of substantial knot slacking. On the other hand, polyester and high-strength poly(vinyl alcohol) sutures showed an excellent in vivo tension holding capacity, along with low elongation and insignificant knot slacking. Clinical performance of these sutures was briefly discussed from the mechanical point of view.

Keywords: suture material, bone fixation, poly(vinyl alcohol), knot property, mechanical testing

DOI: 10.3233/BME-1992-2202

Citation: Bio-Medical Materials and Engineering, vol. 2, no. 2, pp. 71-77, 1992

Authors: Singh, V. R. | Dhawan, J. B.

Article Type: Research Article

Abstract: In this investigation, ultrasonic parameters of kidney stones are measured, in vitro, using a double probe ultrasonic-through-transmission technique. Due to the complex chemical structure of these stones, a large variation in the values of the ultrasonic parameters is found. A correlation between ultrasonic properties and variation in pathology of the renal calculi is also discussed.

Keywords: ultrasonic velocity, attenuation, kidney stone, chemical constituents, hardness, lithotripsy

DOI: 10.3233/BME-1992-2203

Citation: Bio-Medical Materials and Engineering, vol. 2, no. 2, pp. 79-82, 1992

Authors: Fishback, Thomas L. | McMillin, Carl R. | Farona, Michael F.

Article Type: Research Article

Abstract: The purpose of this study was to investigate benzocyclobutene (BCB) derivatives as non-toxic curing agents to replace accelerated sulfur systems in certain synthetic biomedical materials. Prototype artificial spinal discs have been made and implanted in a few patients from a carbon black-filled copolymer of 1-hexene and 5-methyl-1,4-hexadiene (MHD), which is sulfur cured. The polymers investigated in this study were composed of 1-hexene, allyl-BCB, and MHD (or 7-methyl-1,6-octadiene, MOD). Curing was effected through reactions on BCB, forming carbon-carbon crosslinks. Preliminary cytotoxicity tests showed the material to be non-toxic, and the physical and mechanical properties of the BCB-cured materials were comparable with …those of the sulfur-cured polymers. Show more

Keywords: benzocyclobutene, allybenzocyclobutene, curing agent, non-toxic, polyolefins

DOI: 10.3233/BME-1992-2204

Citation: Bio-Medical Materials and Engineering, vol. 2, no. 2, pp. 83-87, 1992

Authors: Azuma, Tadanori | Niiro, Masaya | Motobu, Hirotetsu

Article Type: Research Article

Abstract: Many studies have reported on the removal of pollutants from wastewater using aquatic plants. The water hyacinth has been the most widely used and its system is the most well established. This system however, has a few problems in practical use. The purpose of this study is to obtain basic information on a new system that can substitute for a conventional system or be used as a secondary system to assist the conventional one. We first envisioned a model of this new system and then conducted a preliminary experiment using a small experimental unit to simulate the new system. The …experiment showed that mung beans were a suitable plant for our study. Their removal rate of pollutants was the highest before they developed leaves and started photosynthesis. We found that nutrients were expelled outside the plant root when nutrient concentration inside the plant tissue became too high. Show more

Keywords: environment, pollution, wastewater, eutrophication, aquatic plants, nitrates and phosphates, beans

DOI: 10.3233/BME-1992-2205

Citation: Bio-Medical Materials and Engineering, vol. 2, no. 2, pp. 89-105, 1992

Article Type: Other

DOI: 10.3233/BME-1992-2206

Citation: Bio-Medical Materials and Engineering, vol. 2, no. 2, pp. 107-107, 1992