Journal of biomedical engineering最新文献_第10页

Use of uncalibrated biplanar radiography for the measurement of skeletal coordinates around the shoulder girdle 使用未经校准的双平面x线摄影测量肩带周围的骨骼坐标

Journal of biomedical engineering Pub Date : 1992-11-01 DOI: 10.1016/0141-5425(92)90101-P

G.R. Johnson , T. Buxton , D. House , N. Bogduk

{"title":"Use of uncalibrated biplanar radiography for the measurement of skeletal coordinates around the shoulder girdle","authors":"G.R. Johnson , T. Buxton , D. House , N. Bogduk","doi":"10.1016/0141-5425(92)90101-P","DOIUrl":"10.1016/0141-5425(92)90101-P","url":null,"abstract":"<div><p>Mechanical modelling of the musculoskeletal system is dependent upon information regarding the bony attachments of the relevant muscles; in order to study the biomechanics of the shoulder girdle the authors have identified the muscle attachments in three embalmed cadavers. A simple biplanar radiographic technique was then used to determine the attachment coordinates using frames of reference defined for each bone. This technique, using hand positioning without special fixtures was believed to be sufficiently accurate, bearing in mind the likely degree of biological variation. In order to test this assumption, the accuracy of the technique has been studied by measuring the agreement between the two measurements of the common coordinate in the pairs of radiographs. it was found that for the trunk, the errors in the common coordinate were always less than the natural variation; for the scapula they were of a similar magnitude but, for the humerus, the measurement errors frequently exceeded the variation in the coordinates of muscle attachments. It was concluded that, in general, uncalibrated biplanar radiography was sufficiently accurate for the determination of the spatial coordinates of muscle attachments.</p></div>","PeriodicalId":75992,"journal":{"name":"Journal of biomedical engineering","volume":"14 6","pages":"Pages 490-494"},"PeriodicalIF":0.0,"publicationDate":"1992-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0141-5425(92)90101-P","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"12605120","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 4

Development and validation of a new transducer for intradiscal pressure measurement 一种用于椎间盘内压力测量的新型传感器的开发和验证

Journal of biomedical engineering Pub Date : 1992-11-01 DOI: 10.1016/0141-5425(92)90102-Q

D.S. McNally, M.A. Adams, A.E. Goodship

引用次数: 58

Universal joint slippage as a cause of Hofmann half-frame external fixator failure 万向关节滑移是霍夫曼半框架外固定架失效的原因之一

Journal of biomedical engineering Pub Date : 1992-11-01 DOI: 10.1016/0141-5425(92)90105-T

F.L.I.P. Drijber, J.B. Finlay

引用次数: 8

Drug recirculation model with multiple cycles occurring at unequal time intervals 以不等时间间隔发生多周期的药物再循环模型

Journal of biomedical engineering Pub Date : 1992-11-01 DOI: 10.1016/0141-5425(92)90107-V

Y. Plusquellec , G. Houin

引用次数: 15

Three-dimensional finite element modelling of bone: effects of element size 骨的三维有限元建模:单元尺寸的影响

Journal of biomedical engineering Pub Date : 1992-11-01 DOI: 10.1016/0141-5425(92)90100-Y

J.H. Keyak , H.B. Skinner

{"title":"Three-dimensional finite element modelling of bone: effects of element size","authors":"J.H. Keyak , H.B. Skinner","doi":"10.1016/0141-5425(92)90100-Y","DOIUrl":"10.1016/0141-5425(92)90100-Y","url":null,"abstract":"<div><p>This study quantifies the effects of element size on the stress/strain results of finite element (FE) models of bone that are generated with a previously described automated method. This method uses cube-shaped hexahedral elements, which enabled element shape and aspect ratio to be held constant while the effects of element size were studied. Three models of a human proximal femur, each with a different element size (3.1 mm, 3.8 mm and 4.8 mm), were analysed. Convergence in strain energy of the models had been verified in previous work. The stresses and strains predicted by the models were compared on a pointwise basis using linear regression analysis. There was a general decrease in the level of stress and strain when element size was increased, even though convergence in strain energy had been achieved. An increase in element width from 3.1 mm to 3.8 mm decreased the predicted stresses by 13% to 29% overall; the predicted strains decreased by 4% to 20% for the same increase in element size. These results indicate that linear cube-shaped hexahedral elements must be very small (3 mm on a side or smaller) to represent the sharp variations in mechanical properties that exist in bone, and that use of larger elements decreases the predicted stresses and strains. The elements used in this study are similar to those typically used to represent trabecular bone in conventional (non-automated) FE modelling methods. Therefore, the sensitivity of the stress/strain results to element size that was found for trabecular bone also applies to conventional modelling of such bone. This sensitivity to element size implies that quantitative comparisons of the stresses/strains predicted in trabecular bone by different FE models may not be meaningful if the elements in those models are not the same size. The qualitative results of all three models were in agreement, however, indicating that qualitative comparisons of FE models may be made.</p></div>","PeriodicalId":75992,"journal":{"name":"Journal of biomedical engineering","volume":"14 6","pages":"Pages 483-489"},"PeriodicalIF":0.0,"publicationDate":"1992-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0141-5425(92)90100-Y","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"12605119","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 81

Author index and subject index 作者索引和主题索引

Journal of biomedical engineering Pub Date : 1992-11-01 DOI: 10.1016/0141-5425(92)90109-X

引用次数: 0

Sensitivity coefficients, trajectories and graphs of a human head-movement model 敏感度系数，轨迹和图形的一个人的头部运动模型

Journal of biomedical engineering Pub Date : 1992-11-01 DOI: 10.1016/0141-5425(92)90096-4

W.H. Zangemeister , A.C. Arlt, S. Lehman

引用次数: 7

Finite element stress analysis of simulated metastatic lesions in the lumbar vertebral body 腰椎椎体模拟转移性病变的有限元应力分析

Journal of biomedical engineering Pub Date : 1992-11-01 DOI: 10.1016/0141-5425(92)90098-6

J. Mizrahi , M.J. Silva , W.C. Hayes

{"title":"Finite element stress analysis of simulated metastatic lesions in the lumbar vertebral body","authors":"J. Mizrahi , M.J. Silva , W.C. Hayes","doi":"10.1016/0141-5425(92)90098-6","DOIUrl":"10.1016/0141-5425(92)90098-6","url":null,"abstract":"<div><p>A three-dimensional finite element model of a lumbar vertebral body was developed to study the effects of geometry, material properties and loading conditions on stresses in the presence of metastatic lesions. Parameters studied included location and size of the lesion, modulus of the cortical and trabecular bone within and near the lesion, generalized osteoporosis and load distribution. The results, expressed as ratios of peak values of displacement and stress, relative to a normal baseline case, indicated that the location of a defect which did not penetrate the cortex had a minor influence on the peak displacement and stresses, as did the presence of lesions occupying less than 40% of the volume of the vertebral centrum. A lesion occupying 40% of the centrum volume increased the endplate displacement by 2.9 times, the peak tensile stress in the cortical shell by 2.2 times, and the peak von Mises stress in the endplate by 2.8 times. When this lesion penetrated the cortex, these values increased to 3.8, 3.3 and 4.4 times, repsectively. The most severe case involved a defect penetrating the anterior cortex, osteoporotic bone properties and anteriorly eccentric loading. In this case, the peak values increased to 8.4, 3.4 and 5.9 times their baseline values, respectively. The results are consistent with a model of the vertebral body as a stiff frame of cortical bone surrounding a relatively compliant core of trabecular bone. Only variations in geometry and properties large enough to lessen significantly the structural stiffness affect the peak stresses and displacements. Such a case occurs when an osteoporotic vertebral body containing a lesion of approximately half its volume is subjected to an anterior eccentric load distribution, as occurs in forward flexion. Under these conditions, large increases in the stress magnitudes put the vertebral body at extreme risk of fracture.</p></div>","PeriodicalId":75992,"journal":{"name":"Journal of biomedical engineering","volume":"14 6","pages":"Pages 467-475"},"PeriodicalIF":0.0,"publicationDate":"1992-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0141-5425(92)90098-6","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"12605117","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 33

Analysis of electromagnetic heating patterns inside a cryopreserved organ 低温保存器官内电磁加热模式的分析

Journal of biomedical engineering Pub Date : 1992-11-01 DOI: 10.1016/0141-5425(92)90097-5

X. Bai , D.E. Pegg , S. Evans , J.D.J. Penfold

{"title":"Analysis of electromagnetic heating patterns inside a cryopreserved organ","authors":"X. Bai , D.E. Pegg , S. Evans , J.D.J. Penfold","doi":"10.1016/0141-5425(92)90097-5","DOIUrl":"10.1016/0141-5425(92)90097-5","url":null,"abstract":"<div><p>Computer analysis of the induced electromagnetic field and heating distribution inside cryopreserved organs subjected to electromagnetic illumination at frequencies of 84 MHz 434 MHz and 2.45 GHz were carried out using a spherical model for the organ, with special reference to heating in a single-mode resonant cavity. The interaction between the frequency of the incident field and the size and dielectric properties of the sample was investigated. It is shown that uniform heating of organs is likely to be achieved at lower frequencies, as might be expected. However, the ratio between the power penetration depth for plane waves and the size of the organ is not a sufficient basis on which to judge quantitatively the uniformity of the power absorption. Hot or cold spots can occur within the organ even when this ratio is greater than unity; the wavelength in the material is also an important factor. The results from this study indicate that the use of a resonant cavity as a heating applicator has advantages over plane-wave illumination. A sharp upper limit can be set to the frequency suitable for rapid and uniform heating of a given organ.</p></div>","PeriodicalId":75992,"journal":{"name":"Journal of biomedical engineering","volume":"14 6","pages":"Pages 459-466"},"PeriodicalIF":0.0,"publicationDate":"1992-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0141-5425(92)90097-5","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"12605116","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 13

Running discrete cosine transform 运行离散余弦变换

Journal of biomedical engineering Pub Date : 1992-11-01 DOI: 10.1016/0141-5425(92)90104-S

H Olkkonen

引用次数: 3