The Experts below are selected from a list of 81126 Experts worldwide ranked by ideXlab platform
Carlos Wigderowitz - One of the best experts on this subject based on the ideXlab platform.
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humeral head arthroplasty and its ability to restore original humeral head geometry
Journal of Shoulder and Elbow Surgery, 2013Co-Authors: Fraser Harrold, Carlos WigderowitzAbstract:Background Modern prosthetic components are designed to enable restoration of proximal humeral morphology, provided that a precise osteotomy of the humeral head at the level of the anatomic neck is performed. To determine whether a simulated osteotomy and replacement arthroplasty with an idealized implant were able to restore original head geometry. Materials and methods A handheld digitizer and surface laser scanner were used to digitize 24 humeri. Computer models were used to simulate an osteotomy, performed at the anterior cartilage–metaphyseal interface, and reconstruct the head with a spherical prosthetic head. The head diameter, radius of curvature, and inclination and retroversion angles were calculated for each specimen and compared with the original humeral head. Results The simulated osteotomy resulted in a 4.8° decrease in inclination (P < .01) and 11.3° increase in retroversion (P < .001). The radius of curvature in the coronal plane was not significantly different (P = .284). However, in the axial plane, the prosthesis was significantly larger than the original head for both head diameter (P < .001) and radius of curvature (P < .05). Discussion The study suggests that the humeral head is not a perfect segment of a sphere and an osteotomy along the anterior cartilage–metaphyseal interface does not remove only the proximal humeral articular surface. Even with a fully adaptable prosthetic implant, replacement arthroplasty is not able to restore original head geometry. Conclusions Alterations to head geometry with the osteotomy described may alter the Line of Force through the prosthetic joint, producing eccentric loading at the glenoid, and contribute to early failure.
Fraser Harrold - One of the best experts on this subject based on the ideXlab platform.
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humeral head arthroplasty and its ability to restore original humeral head geometry
Journal of Shoulder and Elbow Surgery, 2013Co-Authors: Fraser Harrold, Carlos WigderowitzAbstract:Background Modern prosthetic components are designed to enable restoration of proximal humeral morphology, provided that a precise osteotomy of the humeral head at the level of the anatomic neck is performed. To determine whether a simulated osteotomy and replacement arthroplasty with an idealized implant were able to restore original head geometry. Materials and methods A handheld digitizer and surface laser scanner were used to digitize 24 humeri. Computer models were used to simulate an osteotomy, performed at the anterior cartilage–metaphyseal interface, and reconstruct the head with a spherical prosthetic head. The head diameter, radius of curvature, and inclination and retroversion angles were calculated for each specimen and compared with the original humeral head. Results The simulated osteotomy resulted in a 4.8° decrease in inclination (P < .01) and 11.3° increase in retroversion (P < .001). The radius of curvature in the coronal plane was not significantly different (P = .284). However, in the axial plane, the prosthesis was significantly larger than the original head for both head diameter (P < .001) and radius of curvature (P < .05). Discussion The study suggests that the humeral head is not a perfect segment of a sphere and an osteotomy along the anterior cartilage–metaphyseal interface does not remove only the proximal humeral articular surface. Even with a fully adaptable prosthetic implant, replacement arthroplasty is not able to restore original head geometry. Conclusions Alterations to head geometry with the osteotomy described may alter the Line of Force through the prosthetic joint, producing eccentric loading at the glenoid, and contribute to early failure.
Xiaojuan Wang - One of the best experts on this subject based on the ideXlab platform.
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synthesis and one dimensional self assembly of acicular nickel nanocrystallites under magnetic fields
Journal of Physical Chemistry B, 2004Co-Authors: Helin Niu, Qianwang Chen, Min Ning, Yaoshun Jia, Xiaojuan WangAbstract:PolycrystalLine nickel wires with an average length of 10 μm and diameter of about 200 nm were prepared at 70 °C by a hydrothermal process with a 0.25 T magnetic field applied. Studies show that the magnetic field induced one-dimensional assembly of acicular Ni nanocrystallites with dimensions of 200 nm in length and 10−30 nm in diameter, leading to the formation of the polycrystalLine nickel wires. Magnetic measurements show saturation magnetization (Ms) of the sample prepared in a 0.25 T external magnetic field is higher than that of the sample synthesized without an external magnetic field applied. It is suggested that the one-dimensional self-assembly of acicular nickel nanocrystallites with their magnetic easy axes [111] aligned along the magnetic Line of Force results in the improvement of the magnetic properties.
Helin Niu - One of the best experts on this subject based on the ideXlab platform.
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synthesis and one dimensional self assembly of acicular nickel nanocrystallites under magnetic fields
Journal of Physical Chemistry B, 2004Co-Authors: Helin Niu, Qianwang Chen, Min Ning, Yaoshun Jia, Xiaojuan WangAbstract:PolycrystalLine nickel wires with an average length of 10 μm and diameter of about 200 nm were prepared at 70 °C by a hydrothermal process with a 0.25 T magnetic field applied. Studies show that the magnetic field induced one-dimensional assembly of acicular Ni nanocrystallites with dimensions of 200 nm in length and 10−30 nm in diameter, leading to the formation of the polycrystalLine nickel wires. Magnetic measurements show saturation magnetization (Ms) of the sample prepared in a 0.25 T external magnetic field is higher than that of the sample synthesized without an external magnetic field applied. It is suggested that the one-dimensional self-assembly of acicular nickel nanocrystallites with their magnetic easy axes [111] aligned along the magnetic Line of Force results in the improvement of the magnetic properties.
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magnetic field induced growth and self assembly of cobalt nanocrystallites
Journal of Materials Chemistry, 2003Co-Authors: Helin Niu, Qianwang Chen, Hongfei Zhu, Yushun Lin, Xing ZhangAbstract:The growth and assembly behavior of cobalt magnetic nanocrystallites under an external magnetic field were studied. Co polycrystalLine wires with an average length of 2 mm and diameter of 13 µm were formed by the self-assembly of Co nanocrystallites (15 nm on average) under the induction of a 0.25 T external magnetic field. The wires were nearly parallel because their axes were all parallel to the magnetic Line of Force. The Ms and Hc values of the sample, 111 emu g−1 and 389 Oe, are higher than those of the sample prepared without an external magnetic field applied (91 emu g−1 and 375 Oe), which might be associated with the special nanostructure in which Co nanocrystallites were arranged in polycrystalLine wires acting as permanent magnetic dipoles. The process could be used to fabricate large arrays of uniform wires of some magnetic materials and improve the magnetic properties of nanoscale magnetic materials.
Min Ning - One of the best experts on this subject based on the ideXlab platform.
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synthesis and one dimensional self assembly of acicular nickel nanocrystallites under magnetic fields
Journal of Physical Chemistry B, 2004Co-Authors: Helin Niu, Qianwang Chen, Min Ning, Yaoshun Jia, Xiaojuan WangAbstract:PolycrystalLine nickel wires with an average length of 10 μm and diameter of about 200 nm were prepared at 70 °C by a hydrothermal process with a 0.25 T magnetic field applied. Studies show that the magnetic field induced one-dimensional assembly of acicular Ni nanocrystallites with dimensions of 200 nm in length and 10−30 nm in diameter, leading to the formation of the polycrystalLine nickel wires. Magnetic measurements show saturation magnetization (Ms) of the sample prepared in a 0.25 T external magnetic field is higher than that of the sample synthesized without an external magnetic field applied. It is suggested that the one-dimensional self-assembly of acicular nickel nanocrystallites with their magnetic easy axes [111] aligned along the magnetic Line of Force results in the improvement of the magnetic properties.