The Experts below are selected from a list of 26661 Experts worldwide ranked by ideXlab platform
Ruth E. Cameron - One of the best experts on this subject based on the ideXlab platform.
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analysis and evaluation of a biomedical polycarbonate urethane tested in an in vitro study and an ovine arthroplasty model part ii in vivo investigation
Biomaterials, 2005Co-Authors: Imran Khan, Nigel J Smith, Eric Jones, Dudley Finch, Ruth E. CameronAbstract:Abstract The polyurethane (PU) elastomer Corethane 80A (Corvita) is being considered as the acetabular Bearing material in a novel total replacement hip joint. Its biostability was investigated in vitro (Analysis and evaluation of a biomedical polycarbonate urethane tested in an in vitro study and an ovine arthroplasty model. Part I: material selection and evaluation, Biomaterials, in press) together with three other commercially available biomedical PUs: Pellethane 2363-80A (DOW Chemical), a polyhexamethylene oxide based PU, PHMO-PU (CSIRO, not supplied as a commercial product) and ChronoFlex AL-80A (CardioTech). From the in vitro studies, Corethane 80A displayed the best overall resistance to hydrolysis, ESC, MIO and calcification, followed by ChronoFlex 80A and PHMO-PU, with Pellethane 80A being the least stable. Building on the in vitro investigation, the follow-up in vivo study (reported here) assessed Corethane 80A as the Bearing Layer in a prototype compliant Layer acetabular cup, in a fully functioning ovine total hip arthoplasty (THA) model. PU degradation in the retrieved cups was analysed using a range of analytical and physical-testing methods including mechanical testing, differential scanning calorimetry, Fourier transform infrared spectroscopy and environmental scanning electron microscopy. The Corethane 80A functioned well in the THA model, with the Bearing surfaces of the retrieved hip cups showing no significant evidence of biodegradation or wear damage after 3 years in vivo. The findings in this study provide compelling evidence for the biostability and effectiveness of acetabular cups incorporating a Corethane 80A compliant Bearing Layer.
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Analysis and evaluation of a biomedical polycarbonate urethane tested in an in vitro study and an ovine arthroplasty model. Part II: in vivo investigation.
Biomaterials, 2005Co-Authors: Imran Khan, Nigel J Smith, Eric Jones, Dudley Finch, Ruth E. CameronAbstract:The polyurethane (PU) elastomer Corethane 80A (Corvita) is being considered as the acetabular Bearing material in a novel total replacement hip joint. Its biostability was investigated in vitro (Analysis and evaluation of a biomedical polycarbonate urethane tested in an in vitro study and an ovine arthroplasty model. Part I: material selection and evaluation, Biomaterials, in press) together with three other commercially available biomedical PUs: Pellethane 2363-80A (DOW Chemical), a polyhexamethylene oxide based PU, PHMO-PU (CSIRO, not supplied as a commercial product) and ChronoFlex AL-80A (CardioTech). From the in vitro studies, Corethane 80A displayed the best overall resistance to hydrolysis, ESC, MIO and calcification, followed by ChronoFlex 80A and PHMO-PU, with Pellethane 80A being the least stable. Building on the in vitro investigation, the follow-up in vivo study (reported here) assessed Corethane 80A as the Bearing Layer in a prototype compliant Layer acetabular cup, in a fully functioning ovine total hip arthoplasty (THA) model. PU degradation in the retrieved cups was analysed using a range of analytical and physical-testing methods including mechanical testing, differential scanning calorimetry, Fourier transform infrared spectroscopy and environmental scanning electron microscopy. The Corethane 80A functioned well in the THA model, with the Bearing surfaces of the retrieved hip cups showing no significant evidence of biodegradation or wear damage after 3 years in vivo. The findings in this study provide compelling evidence for the biostability and effectiveness of acetabular cups incorporating a Corethane 80A compliant Bearing Layer.
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analysis and evaluation of a biomedical polycarbonate urethane tested in an in vitro study and an ovine arthroplasty model part i materials selection and evaluation
Biomaterials, 2005Co-Authors: Imran Khan, Nigel J Smith, Eric Jones, Dudley Finch, Ruth E. CameronAbstract:The polyurethane elastomer (PU) Corethane 80A (Corvita) is being considered as the acetabular Bearing material in a novel total replacement hip joint. The biostability of Corethane 80A was investigated in vitro (this work) and in vivo (reported separately) in a fully functioning ovine total hip arthroplasty (THA) model, with the PU as the Bearing Layer in a prototype compliant Layer acetabular cup. The in vitro studies assessed the resistance of Corethane 80A to the main degradation mechanisms observed in PUs: hydrolysis, environmental stress cracking (ESC), metal ion oxidation (MIO) and calcification. The performance of the polycarbonate PU Corethane 80A was assessed alongside three other commercially available biomedical PUs: polyether PUs Pellethane 2363-80A (DOW Chemical) and PHMO-PU (CSIRO, not supplied as a commercial material) as well as polycarbonate PU ChronoFlex AL-80A (CardioTech). Chemical and structural variables that affect the properties of the materials were analysed with particular attention to the nature of the material's hard and soft segments. PU degradation was probed using a range of analytical tools and physical-testing methods, including mechanical testing, differential scanning calorimetry (DSC), Fourier transform infrared spectroscopy (FTIR) and environmental scanning microscopy (ESEM). Corethane 80A displayed the best overall resistance to hydrolysis, ESC, MIO and calcification, followed by ChronoFlex 80A and PHMO-PU. Pellethane 80A was the least stable. This study provides compelling evidence for the biostability and effectiveness of Corethane 80A and points to its suitability for use as a compliant Bearing Layer in hip arthroplasty, and possibly also other joints.
Fanny Lilian - One of the best experts on this subject based on the ideXlab platform.
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KONTROL KAPASITAS DAYA DUKUNG PONDASI TIANG PANCANG DENGAN METODE FORMULA DINAMIS DAN ANALISIS PACIFIC COAST UNIFORM BUILDING CODE
'Fakultas Teknik Elektronika dan Komputer Universitas Kristen Satya Wacana', 2021Co-Authors: Fanny LilianAbstract:Pondasi merupakan elemen konstruksi yang terletak di bagian terbawah suatu bangunan sipil dan berfungsi untuk meneruskan beban struktur atas (upper structure) ke lapisan tanah dasar (Bearing Layer) yang ada di bawahnya. Pondasi selain harus mampu menerima beban statis dan dinamis, juga perlu diperhitungkan terhadap sifat tanah ketika menerima efek beban getaran yang menyebabkan tanah mencair (liquefaction) sehingga mengakibatkan daya dukungnya menjadi hilang. Perhitungan kapasitas daya dukung pondasi tiang pancang terhadap kedalaman pemancangan merupakan suatu hal yang perlu diperhatikan dalam suatu perencanaan pondasi. Metode yang digunakan dalam kajian ini disesuaikan dengan kelengkapan data yang diimplementasikan ke dalam rumus-rumus yang digunakan. Tujuan dari penelitian yang dilakukan adalah untuk menganalisa kapasitas daya dukung tiang pancang dengan metode dinamis menggunakan teori yang dipublikasikan oleh Pacific Coast Uniform Building Code (PCUBC). Data yang digunakan untuk menganalisa daya dukung pondasi tiang pancang pada metode formula dinamis ini menggunakan data hasil uji pemancangan (calendering) pada pembangunan Gedung Wisma District Sales Office (DSO) Djarum, Kota Banda Aceh. Hasil yang didapatkan dari penelitian ini berupa nilai daya dukung tiang pancang di lapangan. Daya dukung yang dihasilkan pada penggunaan setiap metode formula dinamis dengan nilai kalandering (final set) 7,0 mm pada PC-237 masing-masing adalah, Danish = 33,695 ton, metode Eytelwein = 23,13 ton, metode CNB = 17,600 ton, metode PCUBC = 14,626 ton, dan metode Hiley = 16,55 ton. Dengan demikian dapat disimpulkan bahwa metode PCUBC merupakan metode yang memiliki nilai daya daya dukung tiang terkecil, sedangkan untuk nilai daya dukung tiang yang terbesar diperoleh dengan menggunakan metode Danish.Kata kunci: Beban struktur atas, kontrol daya dukung, pondasi tiang pancang, formula dinamis, data calendering, Pacific Coast Uniform Building Code (PCUBC)Banda Ace
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KONTROL KAPASITAS DAYA DUKUNG PONDASI TIANG PANCANG DENGAN METODE FORMULA DINAMIS DAN ANALISIS PACIFIC COAST UNIFORM BUILDING CODE
'Fakultas Teknik Elektronika dan Komputer Universitas Kristen Satya Wacana', 2021Co-Authors: Fanny LilianAbstract:Pondasi merupakan elemen konstruksi yang terletak di bagian terbawah suatu bangunan sipil dan berfungsi untuk meneruskan beban struktur atas (upper structure) ke lapisan tanah dasar (Bearing Layer) yang ada di bawahnya. Pondasi selain harus mampu menerima beban statis dan dinamis, juga perlu diperhitungkan terhadap sifat tanah ketika menerima efek beban getaran yang menyebabkan tanah mencair (liquefaction) sehingga mengakibatkan daya dukungnya menjadi hilang. Perhitungan kapasitas daya dukung pondasi tiang pancang terhadap kedalaman pemancangan merupakan suatu hal yang perlu diperhatikan dalam suatu perencanaan pondasi. Metode yang digunakan dalam kajian ini disesuaikan dengan kelengkapan data yang diimplementasikan ke dalam rumus-rumus yang digunakan. Tujuan dari penelitian yang dilakukan adalah untuk menganalisa kapasitas daya dukung tiang pancang dengan metode dinamis menggunakan teori yang dipublikasikan oleh Pacific Coast Uniform Building Code (PCUBC). Data yang digunakan untuk menganalisa daya dukung pondasi tiang pancang pada metode formula dinamis ini menggunakan data hasil uji pemancangan (calendering) pada pembangunan Gedung Wisma District Sales Office (DSO) Djarum, Kota Banda Aceh. Hasil yang didapatkan dari penelitian ini berupa nilai daya dukung tiang pancang dengan dimensi 25x25 cm dan kedalaman pemancangan 15 meter dari permukaan tanah. Daya dukung yang dihasilkan pada penggunaan setiap metode formula dinamis dengan nilai kalandering (final set) 7,0 mm pada PC-237 masing-masing adalah, Danish = 33,695 ton, metode Eytelwein = 23,13 ton, metode CNB = 17,600 ton, metode PCUBC = 14,626 ton, dan metode Hiley = 16,55 ton. Dengan demikian dapat disimpulkan bahwa metode PCUBC merupakan metode yang memiliki nilai daya daya dukung tiang terkecil, sedangkan untuk nilai daya dukung tiang yang terbesar diperoleh dengan menggunakan metode Danish.Banda Ace
Imran Khan - One of the best experts on this subject based on the ideXlab platform.
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analysis and evaluation of a biomedical polycarbonate urethane tested in an in vitro study and an ovine arthroplasty model part ii in vivo investigation
Biomaterials, 2005Co-Authors: Imran Khan, Nigel J Smith, Eric Jones, Dudley Finch, Ruth E. CameronAbstract:Abstract The polyurethane (PU) elastomer Corethane 80A (Corvita) is being considered as the acetabular Bearing material in a novel total replacement hip joint. Its biostability was investigated in vitro (Analysis and evaluation of a biomedical polycarbonate urethane tested in an in vitro study and an ovine arthroplasty model. Part I: material selection and evaluation, Biomaterials, in press) together with three other commercially available biomedical PUs: Pellethane 2363-80A (DOW Chemical), a polyhexamethylene oxide based PU, PHMO-PU (CSIRO, not supplied as a commercial product) and ChronoFlex AL-80A (CardioTech). From the in vitro studies, Corethane 80A displayed the best overall resistance to hydrolysis, ESC, MIO and calcification, followed by ChronoFlex 80A and PHMO-PU, with Pellethane 80A being the least stable. Building on the in vitro investigation, the follow-up in vivo study (reported here) assessed Corethane 80A as the Bearing Layer in a prototype compliant Layer acetabular cup, in a fully functioning ovine total hip arthoplasty (THA) model. PU degradation in the retrieved cups was analysed using a range of analytical and physical-testing methods including mechanical testing, differential scanning calorimetry, Fourier transform infrared spectroscopy and environmental scanning electron microscopy. The Corethane 80A functioned well in the THA model, with the Bearing surfaces of the retrieved hip cups showing no significant evidence of biodegradation or wear damage after 3 years in vivo. The findings in this study provide compelling evidence for the biostability and effectiveness of acetabular cups incorporating a Corethane 80A compliant Bearing Layer.
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Analysis and evaluation of a biomedical polycarbonate urethane tested in an in vitro study and an ovine arthroplasty model. Part II: in vivo investigation.
Biomaterials, 2005Co-Authors: Imran Khan, Nigel J Smith, Eric Jones, Dudley Finch, Ruth E. CameronAbstract:The polyurethane (PU) elastomer Corethane 80A (Corvita) is being considered as the acetabular Bearing material in a novel total replacement hip joint. Its biostability was investigated in vitro (Analysis and evaluation of a biomedical polycarbonate urethane tested in an in vitro study and an ovine arthroplasty model. Part I: material selection and evaluation, Biomaterials, in press) together with three other commercially available biomedical PUs: Pellethane 2363-80A (DOW Chemical), a polyhexamethylene oxide based PU, PHMO-PU (CSIRO, not supplied as a commercial product) and ChronoFlex AL-80A (CardioTech). From the in vitro studies, Corethane 80A displayed the best overall resistance to hydrolysis, ESC, MIO and calcification, followed by ChronoFlex 80A and PHMO-PU, with Pellethane 80A being the least stable. Building on the in vitro investigation, the follow-up in vivo study (reported here) assessed Corethane 80A as the Bearing Layer in a prototype compliant Layer acetabular cup, in a fully functioning ovine total hip arthoplasty (THA) model. PU degradation in the retrieved cups was analysed using a range of analytical and physical-testing methods including mechanical testing, differential scanning calorimetry, Fourier transform infrared spectroscopy and environmental scanning electron microscopy. The Corethane 80A functioned well in the THA model, with the Bearing surfaces of the retrieved hip cups showing no significant evidence of biodegradation or wear damage after 3 years in vivo. The findings in this study provide compelling evidence for the biostability and effectiveness of acetabular cups incorporating a Corethane 80A compliant Bearing Layer.
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analysis and evaluation of a biomedical polycarbonate urethane tested in an in vitro study and an ovine arthroplasty model part i materials selection and evaluation
Biomaterials, 2005Co-Authors: Imran Khan, Nigel J Smith, Eric Jones, Dudley Finch, Ruth E. CameronAbstract:The polyurethane elastomer (PU) Corethane 80A (Corvita) is being considered as the acetabular Bearing material in a novel total replacement hip joint. The biostability of Corethane 80A was investigated in vitro (this work) and in vivo (reported separately) in a fully functioning ovine total hip arthroplasty (THA) model, with the PU as the Bearing Layer in a prototype compliant Layer acetabular cup. The in vitro studies assessed the resistance of Corethane 80A to the main degradation mechanisms observed in PUs: hydrolysis, environmental stress cracking (ESC), metal ion oxidation (MIO) and calcification. The performance of the polycarbonate PU Corethane 80A was assessed alongside three other commercially available biomedical PUs: polyether PUs Pellethane 2363-80A (DOW Chemical) and PHMO-PU (CSIRO, not supplied as a commercial material) as well as polycarbonate PU ChronoFlex AL-80A (CardioTech). Chemical and structural variables that affect the properties of the materials were analysed with particular attention to the nature of the material's hard and soft segments. PU degradation was probed using a range of analytical tools and physical-testing methods, including mechanical testing, differential scanning calorimetry (DSC), Fourier transform infrared spectroscopy (FTIR) and environmental scanning microscopy (ESEM). Corethane 80A displayed the best overall resistance to hydrolysis, ESC, MIO and calcification, followed by ChronoFlex 80A and PHMO-PU. Pellethane 80A was the least stable. This study provides compelling evidence for the biostability and effectiveness of Corethane 80A and points to its suitability for use as a compliant Bearing Layer in hip arthroplasty, and possibly also other joints.
Keni Zhang - One of the best experts on this subject based on the ideXlab platform.
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effects of impermeable boundaries on gas production from hydrate accumulations in the shenhu area of the south china sea
Energies, 2013Co-Authors: Keni Zhang, Yu ZhangAbstract:Based on currently available data from site measurements and the preliminary estimates of the gas production potential from the hydrate accumulations at the SH7 site in the Shenhu Area using the depressurization method with a single horizontal well placed in the middle of the Hydrate-Bearing Layer (HBL), the dependence of production performance on the permeabilities of the overburden (OB) and underburden (UB) Layers was investigated in this modeling study. The simulation results indicated that the temperature and the pressure of the HBL were affected by the permeabilities of OB and UB and the effect of depressurization with impermeable OB and UB was significantly stronger than that with permeable boundaries. Considering the percentage of hydrate dissociation, the gas production rate and the gas-to-water ratio, the hydrate deposit with impermeable OB and UB was expected to be the potential gas production target.
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a huff and puff production of gas hydrate deposits in shenhu area of south china sea through a vertical well
Journal of Petroleum Science and Engineering, 2012Co-Authors: George J Moridis, Keni ZhangAbstract:Abstract The Shenhu area on the northern continental slope of the South China Sea is one of the most promising fields for gas hydrate exploitation. Drilling and sampling has indicated high saturations of methane hydrate in clay silty sediments at drilling site SH2. The hydrate-Bearing Layer is overlain and underlain by permeable zones of mobile water, and the system does not appear to be bounded by low-permeability strata. In this study a huff-and-puff method is used to producing gas from the hydrate accumulation. We simulate numerically the hydrate dissociation and gas production by alternately injecting hot water and producing fluids at a vertical well. The simulations show the gas production rate in huff-and-puff operations is very small (50–140 m 3 /d), and unacceptable for commercial production. The calculation also indicated secondary hydrates forms at the very early period of injecting operations, and then gas is released due to the thermal stimulation of hot water, but the amount of released gas in the injection periods of hot water is much smaller than that converts into secondary hydrates. In the production operations, much of gas is released from the hydrates due to a small depressurization at the well, but the released gas can not produce effectively due to the small pressure gradient, and thus remains in the reservoir and converts into secondary hydrates in the next operation of injecting hot water. The study provides an insight into the production potential of the Shenhu hydrate accumulations through the huff-and-puff method, and a basis for the analysis of the economic feasibility of gas production from that area.
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evaluation on gas production potential from laminar hydrate deposits in shenhu area of south china sea through depressurization using vertical wells
Journal of Petroleum Science and Engineering, 2012Co-Authors: Keni Zhang, George J MoridisAbstract:Abstract Gas hydrates are solid crystalline compounds in which gas molecules are lodged in lattices of ice crystals. Shenhu area is considered as one of the most promising fields on north continental slope of the South China Sea (SCS). Drilling and sampling at the site has indicated occurrences of methane hydrate in clay silty sediments. The thin Hydrate-Bearing Layer (HBL) is overlain and underlain by zones of mobile water, and the Layer does not appear to be bounded by low-permeability strata. In this study we assess by means of numerical simulation the production potential of the laminar hydrate deposit at drilling site SH3 in the Shenhu area. We simulate the hydrate dissociation and the gas production induced by depressurization at a vertical well. To minimize gas losses through the overburden and excessive water production through proximity to the permeable, water-saturated zones, a perforated interval is limited to the middle section of the vertical well within the hydrate Layer. The simulations show that productions from depressurization-induced dissociation through a vertical well at constant well pressure do not appear to be a promising approach in the deposits of low hydraulic diffusion. The production of hydrate-originating gas decreases at the beginning of the production and then keep stable in the reference case and the average production is 211 m3/d. The deposit permeability is considered as the most insensitive parameter to enhance the gas production. And the production potential is much lower than that of deposits having an impermeable upper boundary as expectation.
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evaluation of gas production potential from marine gas hydrate deposits in shenhu area of south china sea
Energy & Fuels, 2010Co-Authors: Gang Li, George J Moridis, Keni Zhang, Xiaosen LiAbstract:The Shenhu Area is located in the Pearl River Mouth Basin, the northern continental slope of the South China Sea. In 2007, gas hydrate samples were recovered during the scientific expedition conducted by the China Geological Survey in the area. Using numerical simulation and currently available data from site measurements, including the water depth, thickness of the hydrate-Bearing Layer (HBL), sediment porosity, salinity, and pressures and temperatures at key locations, we developed preliminarily estimates of the production potential of these hydrates as gas-producing resource. We used measurements of ambient temperature in the sediments to determine the local geothermal gradient. Evidence from this and other field studies showed that the initial pressure distribution followed the hydrostatic gradient. Direct measurements from core samples provided estimates of the initial hydrate saturation and of the intrinsic permeabilities in the various strata of the system. The hydrate accumulations in the Shenhu A...
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the use of huff and puff method in a single horizontal well in gas production from marine gas hydrate deposits in the shenhu area of south china sea
Journal of Petroleum Science and Engineering, 2010Co-Authors: George J Moridis, Keni ZhangAbstract:Abstract The Shenhu Area is located in the Pearl River Mouth Basin, the northern continental slope of the South China Sea. It is expected that the Shenhu Area will become a strategic area of gas hydrate exploitation in China. Based on currently available data from site measurements, including water depth, thickness of the Hydrate-Bearing Layer (HBL), sediment porosity, salinity and pressures and temperatures at key locations, it is possible to develop preliminarily estimates of the gas production potential by numerical modeling. We used measurements of ambient temperature in the sediments to determine the local geothermal gradient. Estimates of the hydrate saturation and the intrinsic permeabilities of the system formations were obtained from direct measurements. The hydrate accumulations in the Shenhu Area are similar to Class 3 deposits (involving only an HBL), and the overburden and underburden Layers are assumed to be permeable. These unconfined deposits may represent a large challenge for gas production. In this modeling study, we estimated gas production from hydrates at the SH7 drilling site of the Shenhu Area by means of the stream huff and puff method using a single horizontal well in the middle of the HBL. The simulation results indicate that the hydrate dissociated zone expands around the well, and the hydrate formation occurs during the injection stage of the huff and puff process. The higher temperature of the injected brine appears to have a limited effect on gas production using the huff and puff method. Reasonable injection and production rates should be adopted to avoid the over pressurization and depressurization during each huff and puff cycle. Production is invariably lower than that attainable in a confined system, and thermal stimulation is shown to have an effect over a limited range around the well. The sensitivity analysis demonstrates the dependence of gas production on the level of the increment of the injection and production rates of the huff and puff process, the temperature of the injected brine and the existence of brine injection during the injection stage.
Eric Jones - One of the best experts on this subject based on the ideXlab platform.
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analysis and evaluation of a biomedical polycarbonate urethane tested in an in vitro study and an ovine arthroplasty model part ii in vivo investigation
Biomaterials, 2005Co-Authors: Imran Khan, Nigel J Smith, Eric Jones, Dudley Finch, Ruth E. CameronAbstract:Abstract The polyurethane (PU) elastomer Corethane 80A (Corvita) is being considered as the acetabular Bearing material in a novel total replacement hip joint. Its biostability was investigated in vitro (Analysis and evaluation of a biomedical polycarbonate urethane tested in an in vitro study and an ovine arthroplasty model. Part I: material selection and evaluation, Biomaterials, in press) together with three other commercially available biomedical PUs: Pellethane 2363-80A (DOW Chemical), a polyhexamethylene oxide based PU, PHMO-PU (CSIRO, not supplied as a commercial product) and ChronoFlex AL-80A (CardioTech). From the in vitro studies, Corethane 80A displayed the best overall resistance to hydrolysis, ESC, MIO and calcification, followed by ChronoFlex 80A and PHMO-PU, with Pellethane 80A being the least stable. Building on the in vitro investigation, the follow-up in vivo study (reported here) assessed Corethane 80A as the Bearing Layer in a prototype compliant Layer acetabular cup, in a fully functioning ovine total hip arthoplasty (THA) model. PU degradation in the retrieved cups was analysed using a range of analytical and physical-testing methods including mechanical testing, differential scanning calorimetry, Fourier transform infrared spectroscopy and environmental scanning electron microscopy. The Corethane 80A functioned well in the THA model, with the Bearing surfaces of the retrieved hip cups showing no significant evidence of biodegradation or wear damage after 3 years in vivo. The findings in this study provide compelling evidence for the biostability and effectiveness of acetabular cups incorporating a Corethane 80A compliant Bearing Layer.
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Analysis and evaluation of a biomedical polycarbonate urethane tested in an in vitro study and an ovine arthroplasty model. Part II: in vivo investigation.
Biomaterials, 2005Co-Authors: Imran Khan, Nigel J Smith, Eric Jones, Dudley Finch, Ruth E. CameronAbstract:The polyurethane (PU) elastomer Corethane 80A (Corvita) is being considered as the acetabular Bearing material in a novel total replacement hip joint. Its biostability was investigated in vitro (Analysis and evaluation of a biomedical polycarbonate urethane tested in an in vitro study and an ovine arthroplasty model. Part I: material selection and evaluation, Biomaterials, in press) together with three other commercially available biomedical PUs: Pellethane 2363-80A (DOW Chemical), a polyhexamethylene oxide based PU, PHMO-PU (CSIRO, not supplied as a commercial product) and ChronoFlex AL-80A (CardioTech). From the in vitro studies, Corethane 80A displayed the best overall resistance to hydrolysis, ESC, MIO and calcification, followed by ChronoFlex 80A and PHMO-PU, with Pellethane 80A being the least stable. Building on the in vitro investigation, the follow-up in vivo study (reported here) assessed Corethane 80A as the Bearing Layer in a prototype compliant Layer acetabular cup, in a fully functioning ovine total hip arthoplasty (THA) model. PU degradation in the retrieved cups was analysed using a range of analytical and physical-testing methods including mechanical testing, differential scanning calorimetry, Fourier transform infrared spectroscopy and environmental scanning electron microscopy. The Corethane 80A functioned well in the THA model, with the Bearing surfaces of the retrieved hip cups showing no significant evidence of biodegradation or wear damage after 3 years in vivo. The findings in this study provide compelling evidence for the biostability and effectiveness of acetabular cups incorporating a Corethane 80A compliant Bearing Layer.
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analysis and evaluation of a biomedical polycarbonate urethane tested in an in vitro study and an ovine arthroplasty model part i materials selection and evaluation
Biomaterials, 2005Co-Authors: Imran Khan, Nigel J Smith, Eric Jones, Dudley Finch, Ruth E. CameronAbstract:The polyurethane elastomer (PU) Corethane 80A (Corvita) is being considered as the acetabular Bearing material in a novel total replacement hip joint. The biostability of Corethane 80A was investigated in vitro (this work) and in vivo (reported separately) in a fully functioning ovine total hip arthroplasty (THA) model, with the PU as the Bearing Layer in a prototype compliant Layer acetabular cup. The in vitro studies assessed the resistance of Corethane 80A to the main degradation mechanisms observed in PUs: hydrolysis, environmental stress cracking (ESC), metal ion oxidation (MIO) and calcification. The performance of the polycarbonate PU Corethane 80A was assessed alongside three other commercially available biomedical PUs: polyether PUs Pellethane 2363-80A (DOW Chemical) and PHMO-PU (CSIRO, not supplied as a commercial material) as well as polycarbonate PU ChronoFlex AL-80A (CardioTech). Chemical and structural variables that affect the properties of the materials were analysed with particular attention to the nature of the material's hard and soft segments. PU degradation was probed using a range of analytical tools and physical-testing methods, including mechanical testing, differential scanning calorimetry (DSC), Fourier transform infrared spectroscopy (FTIR) and environmental scanning microscopy (ESEM). Corethane 80A displayed the best overall resistance to hydrolysis, ESC, MIO and calcification, followed by ChronoFlex 80A and PHMO-PU. Pellethane 80A was the least stable. This study provides compelling evidence for the biostability and effectiveness of Corethane 80A and points to its suitability for use as a compliant Bearing Layer in hip arthroplasty, and possibly also other joints.