Bio-Medical Materials and Engineering - Volume 21, issue 4

Authors: Xu, Xueyan S. | Riley, Danny A. | Persson, Magnus | Welcome, Daniel E. | Krajnak, Kristine | Wu, John Z. | Govinda Raju, Sandya R. | Dong, Ren G.

Article Type: Research Article

Abstract: Gloves with anti-vibration features are increasingly used to reduce impact vibrations or shocks transmitted to the hands of power tool operators. Selection and evaluation of the glove materials are important steps in the designs of such gloves. In the current study, we proposed an approach to objectively evaluate the effectiveness of the glove materials using a rat-tail impact model. As a critical part of a systematic investigation, we examined the vibration reduction characteristics of typical resilient glove materials (air bladders and viscoelastic gels) and the impact vibrations transmitted to the rat tail. A special test platform that mimics impact tool …vibrations was constructed and used in the experiment. A scanning laser vibrometer was used to measure the vibration at points across the platform surface under several different test conditions. The peak acceleration was found to be greatly attenuated by the glove materials, especially by using strips from a gel-filled glove. The rat tail was found to effectively absorb the high-frequency vibration. However, the glove materials and the rat tail did not reduce the frequency-weighted acceleration. The implications of the experimental results are discussed. Show more

Keywords: , Hand–arm vibration, animal model, rat-tail model, anti-vibration gloves, hand–arm vibration syndrome

DOI: 10.3233/BME-2011-0669

Citation: Bio-Medical Materials and Engineering, vol. 21, no. 4, pp. 193-211, 2011

Authors: Park, Chan-Hee | Tijing, Leonard D. | Yun, Yeoheung | Kim, Cheol Sang

Article Type: Research Article

Abstract: This article describes a preliminary investigation and prototype fabrication of a novel potential sensing method to continuously monitor vascular stent fractures. A potential measurement system consisting of Wheatstone bridge circuit and signal conditioning circuit was designed for the cardiovascular stent durability and fatigue test. Each end of a bare and polyurethane-covered Nitinol vascular stent was electrically connected to the potential measurement system and then immersed either in simulated body fluid (SBF) media or distilled water at 36.4±1°C. When the stent experienced fracture (i.e., a cut), its electrical potential decreased with an increase in electrical resistance. This method successfully measured fractures …in the stent regardless of location. Furthermore, the number of cycles at the onset of stent fracture was accurately detected and continuously monitored using this technique. Thus, the present fracture detection method, which to our knowledge is the first ever report to use electrical potential measurement for stent durability test, gives a fast, real-time, accurate and efficient detection of fractures in stent during in vitro fatigue and durability test. Show more

Keywords: , Electrical potential, stent fracture, fatigue and durability test, vascular stent, Nitinol, Wheatstone bridge circuit

DOI: 10.3233/BME-2011-0670

Citation: Bio-Medical Materials and Engineering, vol. 21, no. 4, pp. 213-222, 2011

Authors: Mutlu, Ilven | Oktay, Enver

Article Type: Research Article

Abstract: In this study, biocompatibility of 17-4 PH stainless steel foam for biomedical implant applications was investigated. 17-4 PH stainless steel foams having porosities in the range of 40–82% with an average pore size of around 600 μm were produced by space holder-sintering technique. Sintered foams were precipitation hardened for times of 1–6 h at temperatures between 450–570°C. Compressive yield strength and Young's modulus of aged stainless steel foams were observed to vary between 80–130 MPa and 0.73–1.54 GPa, respectively. Pore morphology, pore size and the mechanical properties of the 17-4 PH stainless steel foams were close to cancellous bone. In …vitro evaluations of cytotoxicity of the foams were investigated by XTT and MTT assays and showed sufficient biocompatibility. Surface roughness parameters of the stainless steel foams were also determined to characterize the foams. Show more

Keywords: Metal foam, implant, 17-4 PH stainless steel, biocompatibility, cytotoxicity

DOI: 10.3233/BME-2011-0671

Citation: Bio-Medical Materials and Engineering, vol. 21, no. 4, pp. 223-233, 2011

Authors: Tadano, Shigeru | Nakatsuchi, Hiroki | Goto, Naoko | Fujisaki, Kazuhiro | Nakatsuchi, Yukio

Article Type: Research Article

Abstract: Hip fracture in the aged easily occurs by falls and may cause these persons to become bedridden. Hip pads are effective in protecting hip fracture as they directly deflect and absorb the impact forces by falls. It is necessary for the material and the structure of hip pads to be designed to realize both high impact absorption and compliance (comfort during wearing). In this report, an impact testing system was developed to test the impact absorbing performance of hip pad with air cushions designed by the research group. The impact absorbing performance was evaluated by the impact load, collision time, …and maximum load. To confirm the effectiveness in protecting against hip fracture, an impact force was applied to the greater trochanter of the human femur and the degree of fracture was measured by X-ray examination. As a result, the hip pad with air cushions had a high impact absorbing performance and was sufficiently effective to protect against hip fracture. Show more

Keywords: Biomechanics, hip pad, hip fracture, fall, impact test

DOI: 10.3233/BME-2011-0672

Citation: Bio-Medical Materials and Engineering, vol. 21, no. 4, pp. 235-246, 2011

Authors: Samad, Hamizah Abd | Jaafar, Mariatti | Othman, Radzali | Kawashita, Masakazu | Razak, Noor Hayati Abdul

Article Type: Research Article

Abstract: In present study, a new composition of glass-ceramic was synthesized based on the Na2 O–CaO–SiO2 –P2 O5 glass system. Heat treatment of glass powder was carried out in 2 stages: 600°C as the nucleation temperature and different temperature on crystallization at 850, 950 and 1000°C. The glass-ceramic heat-treated at 950°C was selected as bioactive filler in commercial PMMA bone cement; (PALACOS® LV) due to its ability to form 2 high crystallization phases in comparison with 850 and 1000°C. The results of this newly glass-ceramic filled PMMA bone cement at 0–16 wt% of filler loading were compared with those …of hydroxyapatite (HA). The effect of different filler loading on the setting properties was evaluated. The peak temperature during the polymerization of bone cement decreased when the liquid to powder (L/P) ratio was reduced. The setting time, however, did not show any trend when filler loading was increased. In contrast, dough time was observed to decrease with increased filler loading. Apatite morphology was observed on the surface of the glass-ceramic and selected cement after bioactivity test. Show more

Keywords: Bioactive bone cement, polymethylmethacrylate, bioactivity, hydroxyapatite, glass-ceramics

DOI: 10.3233/BME-2011-0673

Citation: Bio-Medical Materials and Engineering, vol. 21, no. 4, pp. 247-258, 2011

Authors: Sun, Ziling | Bai, Lun

Article Type: Research Article

Abstract: The purpose of this paper is to explore neovascularization in the biomaterials implanted in vivo. Capillaries formation of dermis defect filled with porous silk fibroin films (PSFFs) implant were investigated in rat at different times. Vascular endothelial growth factor (VEGF), CD34 and hypoxia inducible factor-1 (HIF) were observed in inflammatory cells and fibroblast in PSFFs by day 1, but expression in HIF and VEGF decreased by day 7, otherwise VEGF expressed in vascular endothelial cell increased by day 15 and 25, respectively. VEGF, angiopoietin 1 (Ang-1) and integrins αv and integrins β3 in PSFFs were observed by Reverse transcription-polymerase chain …reaction (RT-PCR). Polyvinyl alcohol (PVA) sponge was control. PSFFs have better neovascularization than that of PVA expression of VEGF, HIF and angiogenesis in immunohistochemical and mRNA level. Show more

Keywords: PSFFs, angiogenesis, endothelial cell, VEGF, HIF

DOI: 10.3233/BME-2011-0674

Citation: Bio-Medical Materials and Engineering, vol. 21, no. 4, pp. 259-270, 2011