Journal of biomedical engineering最新文献

{"title":"A Non-Local Means Approach for PET Image Denoising","authors":"Yinyong, L. Jie","doi":"10.1007/978-3-642-03879-2_36","DOIUrl":"https://doi.org/10.1007/978-3-642-03879-2_36","url":null,"abstract":"","PeriodicalId":75992,"journal":{"name":"Journal of biomedical engineering","volume":"27 1","pages":"127-127"},"PeriodicalIF":0.0,"publicationDate":"2009-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"51069745","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}

{"title":"Lifespan of subcutaneous glucose sensors and their performances during dynamic glycaemia changes in rats","authors":"Elisabetta Bobbioni-Harsch ,&nbsp;Françoise Rohner-Jeanrenaud ,&nbsp;Milena Koudelka ,&nbsp;Nico de Rooij ,&nbsp;Bernard Jeanrenaud","doi":"10.1016/0141-5425(93)90058-7","DOIUrl":"10.1016/0141-5425(93)90058-7","url":null,"abstract":"<div><p>Performances of a glucose sensor have been investigated during dynamic variations of plasma glucose levels. Subcutaneous glucose concentrations measured by the sensors were calculated by a one-point calibration, performed in basal conditions. A first group of sensors were chronically implanted in the subcutaneous tissue of normal rats. The animals were submitted to glucagon and insulin injection, in order to induce rapid modifications of their glycaemia. This test was repeated at different days after implantation in order to investigate the lifespan and the performance of the sensors. All the sensors were working 1 or 2 days after implantation, and 70% adequately responded to glycaemia variations at day 3 or 4. The quality of the sensors' performance remained constant as a function of the time. With a second group of sensors, we demonstrated that an efficient sterilization procedure did not alter the sensors' characteristics. At the day of implantation, the sterilized sensors' performance, during dynamic variations of plasma glucose levels, was closely similar to that of the non-sterilized sensors. The animals bearing the sterilized devices were rendered diabetic by steptozotocin (STZ) injection. Once the rats had developed a severe hyperglycaemia (1–3 days after STZ), they were injected with intravenous insulin. The subcutaneously implanted glucose sensors correctly followed the decline in plasma glucose levels. We therefore conclude that our sensor could represent a useful tool for short-term continuous blood monitoring.</p></div>","PeriodicalId":75992,"journal":{"name":"Journal of biomedical engineering","volume":"15 6","pages":"Pages 457-463"},"PeriodicalIF":0.0,"publicationDate":"1993-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0141-5425(93)90058-7","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"19265969","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}

{"title":"Design and evaluation of a device for measurement of interface pressure","authors":"M.D. Steinberg ,&nbsp;E.D. Cooke","doi":"10.1016/0141-5425(93)90059-8","DOIUrl":"10.1016/0141-5425(93)90059-8","url":null,"abstract":"<div><p>An electropneumatic device has been designed to measure the interface pressure profile under compression bandages. The device uses commercially available pneumatic sensors (Talley Group Ltd, SJ235/3) and measures interface pressure at up to eight sites simultaneously along the lower limb, with an accuracy of ± 3 mmHg. Measurements can be made in one of two modes: continuously at a rate of up to three samples per second with the results output to a suitable display device, or single measurements of interface pressure can be made and displayed on a digital display incorporated in the device. This enables the monitoring and recording of interface pressure under compression bandages during either ambulation or passive recumbency. The electropneumatic system is described together with its following characteristics: the hysteresis of the Talley pneumatic sensors, the accuracy of pressure measurement and the maximum achievable sample rate. Dynamic measurements in a single normal volunteer are shown.</p></div>","PeriodicalId":75992,"journal":{"name":"Journal of biomedical engineering","volume":"15 6","pages":"Pages 464-468"},"PeriodicalIF":0.0,"publicationDate":"1993-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0141-5425(93)90059-8","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"19265970","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}

{"title":"The effect of shear forces externally applied to skin surface on underlying tissues","authors":"Ming Zhang,&nbsp;V.C. Roberts","doi":"10.1016/0141-5425(93)90057-6","DOIUrl":"10.1016/0141-5425(93)90057-6","url":null,"abstract":"<div><p>The effects of shear forces externally applied to the skin surface on the underlying tissues have been investigated. An analysis of the internal stresses and strains was conducted using a simplified model incorporating elasticity theory. Skin blood flow was measured using laser Doppler flowmetry while variable shear forces over a range of 0–250g were applied to the skin surface. The theoretical model predicts that the application of surface shear forces alters the internal stress distribution and makes the shear and compressive components of stresses increase ahead of the surface force application point. The force resulting from concomitant application of shear and normal force determines the internal maximum stress and strain. Theoretically, the shear force should have the same effects on the underlying tissues as normal force. The experimental investigations revealed that the skin blood flow decreased roughly linearly with the increase of shear forces. When a shear force equal to the normal force was applied, the flux decreased by 45%, nearly equal to the increasing magnitude (41%) of resultant of normal and shear forces.</p></div>","PeriodicalId":75992,"journal":{"name":"Journal of biomedical engineering","volume":"15 6","pages":"Pages 451-456"},"PeriodicalIF":0.0,"publicationDate":"1993-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0141-5425(93)90057-6","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"19265968","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}

{"title":"Author index and subject index","authors":"","doi":"10.1016/0141-5425(93)90070-F","DOIUrl":"https://doi.org/10.1016/0141-5425(93)90070-F","url":null,"abstract":"","PeriodicalId":75992,"journal":{"name":"Journal of biomedical engineering","volume":"15 6","pages":"Pages 523-528"},"PeriodicalIF":0.0,"publicationDate":"1993-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0141-5425(93)90070-F","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"137160907","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}

{"title":"Direct and indirect methods for the quantification of leg volume: comparison between water displacement volumetry, the disk model method and the frustum sign model method, using the correlation coefficient and the limits of agreement","authors":"D.M.K.S. Kaulesar Sukul ,&nbsp;P.T. den Hoed ,&nbsp;E.J. Johannes ,&nbsp;R. van Dolder ,&nbsp;E. Benda","doi":"10.1016/0141-5425(93)90062-4","DOIUrl":"10.1016/0141-5425(93)90062-4","url":null,"abstract":"<div><p>Volume changes can be measured either directly by water-displacement volumetry or by various indirect methods in which calculation of the volume is based on circumference measurements. The aim of the present study was to determine the most appropriate indirect method for lower leg volume calculation using water displacement volumetry as a ‘golden standard’. For 20 male volunteers, age range: 20–35 years, the volume of both lower legs was determined directly by water-displacement volumetry, and indirectly by the frustum sign model method and the disc model method. Calculation of the correlation coefficient and the limits of agreement showed that water-displacement volumetry and the disc model method are interchangeable (<em>r</em> = + 0.99, mean ± 2s = − 45 ± 78 ml), whereas this does not hold for the frustum sign model (<em>r</em> = + 0.93, mean ± 2s = 521 ± 238 ml). In the clinical situation volume measurement can be valuable for monitoring of the severity of oedema or haematoma occurrence after surgery or severe trauma. This non-invasive diagnostic aid may be a valuable adjuvant means of diagnosis for several volume dependent disorders of the extremities.</p></div>","PeriodicalId":75992,"journal":{"name":"Journal of biomedical engineering","volume":"15 6","pages":"Pages 477-480"},"PeriodicalIF":0.0,"publicationDate":"1993-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0141-5425(93)90062-4","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"19265102","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}

{"title":"Determination of fatigue in the electrically stimulated quadriceps muscle and relative effect of ischaemia","authors":"E. Rabischong ,&nbsp;D. Guiraud","doi":"10.1016/0141-5425(93)90056-5","DOIUrl":"10.1016/0141-5425(93)90056-5","url":null,"abstract":"<div><p>The creation of muscle fatigue using surface electrical stimulation represents a highly reproducible phenomenon in spinal cord injured patients. The torque output was recorded as a function of time. The fatigue curves recorded over 110s exhibited three main parts: first, a plateau of short duration, followed by a more or less steep slope and then a second plateau which was maintained for a long time. This phenomenon was fitted using an exponential equation which had been developed and four parameters introduced that outlined to the muscle behaviour. A set of fatigue indices was defined to characterize the asymptotic value, the slope, the coordinates of the inflexion point, the time constant and the vertical amplitude of the curve recorded. Two populations were studied; a group of 11 thoracic level of injury paraplegic patients and a group of 10 able-bodied control subjects. The computed coefficients of determination, r², were of very high values (0.99). Therefore, fatigue indices gave reliable information. Torque output did not differ between the two populations until 25 s had elapsed, but from 30s onwards it was markedly lower in paraplegics. The residual torque output was 21.1 ± 10.6% in the paraplegic group while it was 58.5 ± 8.9% in the control group. The effect of blood supply in the production of fatigue was also studied by repeating the same test using a tourniquet at the groin level. The residual torque became 14.7 ± 2.3% in the paraplegic group and 42.9 ± 6.3% in the control group. This test permitted the determination at a gross level of the different metabolic phases and therefore the recruitment of the different populations of muscle fibres within the quadriceps. Fast fatiguable fibres (type FF) produced the maximum output during the first phase, then fast resistant (type FR) explained the slope, and slow fibres (type S) were responsible for the second plateau. The effects of the tourniquet were obvious on the fatigue indices in both populations. In the spinal cord injured patients, there appeared to be a lack of slow fibres, probably due to disuse. Fatigue appeared to be independent from blood flow in paraplegics.</p></div>","PeriodicalId":75992,"journal":{"name":"Journal of biomedical engineering","volume":"15 6","pages":"Pages 443-450"},"PeriodicalIF":0.0,"publicationDate":"1993-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0141-5425(93)90056-5","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"19265967","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}

{"title":"The use of strain energy as a convergence criterion in the finite element modelling of bone and the effect of model geometry on stress convergence","authors":"L.W. Marks ,&nbsp;T.N. Gardner","doi":"10.1016/0141-5425(93)90061-3","DOIUrl":"10.1016/0141-5425(93)90061-3","url":null,"abstract":"<div><p>Keyak and Skinner¹ state that the adequacy of a finite element mesh may be verified by confirming that convergence of strain energy has been achieved. The paper concludes by stating that convergence of strain energy does not ensure that a particular mesh is adequate for producing accurate stress/strain results, and that only qualitative results can be achieved from 3D models of bone. This conclusion is challenged and the effect of element size on stress convergence is clarified. The influence of element size on stress convergence in regions of surface irregularity is studied and current methods are discussed that facilitate convergence.</p></div>","PeriodicalId":75992,"journal":{"name":"Journal of biomedical engineering","volume":"15 6","pages":"Pages 474-476"},"PeriodicalIF":0.0,"publicationDate":"1993-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0141-5425(93)90061-3","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"19265101","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}

{"title":"Three dimensional shape reconstruction and finite element analysis of femur before and after the cementless type of total hip replacement","authors":"Y.K. Kang ,&nbsp;H.C. Park ,&nbsp;Y. Youm ,&nbsp;I.K. Lee ,&nbsp;M.H. Ahn ,&nbsp;J.C. Ihn","doi":"10.1016/0141-5425(93)90065-7","DOIUrl":"10.1016/0141-5425(93)90065-7","url":null,"abstract":"<div><p>Computerized tomography was used to reconstruct a shape, and stresses in three-dimensional objects were analysed. The human femur, which has a very irregular shape, was chosen as an object. CT image data of a cadaver femur were transferred to a computer, and an edge extraction program generated the cross-section of bone by specifying a range of CT values for each slice. Pixel data from the CT scan are converted into a vector of points (x, y, z) which can specify the boundaries of bone. Lateral surfaces are defined by stacking up the slices and making use of the vectorized data. Intermediate and oblique cross-sections can be obtained by an interpolation technique. The constructed model was used as input data for the finite element analysis. To understand the stress distributions before and after the cementless type of total hip replacement, a three-dimensional finite element stress analysis of the bone-implant system was carried out, assuming micromotions between the stem and the femur. The analysis was done for both frictionless and friction cases, modelling the contact point with a gap element having isotropic friction. The analysis shows that the stress is not concentrated on the femoral calcar when the friction coefficient is large.</p></div>","PeriodicalId":75992,"journal":{"name":"Journal of biomedical engineering","volume":"15 6","pages":"Pages 497-504"},"PeriodicalIF":0.0,"publicationDate":"1993-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0141-5425(93)90065-7","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"19265105","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}

{"title":"AZTDIS — a two-phase real-time ECG data compressor","authors":"S.C. Tai","doi":"10.1016/0141-5425(93)90067-9","DOIUrl":"10.1016/0141-5425(93)90067-9","url":null,"abstract":"<div><p>An ECG sampled at a rate of 360 samples s⁻¹ or more produces a large amount of redundant data that are difficult to store and transmit; we therefore need a process to represent the signals with clinically acceptable fidelity and with as small a number of code bits as possible. In this paper, a real-time ECG data-compression algorithm, AZTDIS, is presented. AZTDIS is an efficient algorithm which locates significant samples and at the same time encodes linear segments between them by using linear interpolation. The significant samples selected include, but are not limited to, the samples that have significant displacement from the encoded signal such that the allowed maximal error is limited to a constant ϵ, which is specified by the user. The way that AZTDIS computes the displacement of a sample from the encoded signal guarantees that the high activity regions are more accurately coded. The results from AZTDIS are compared with those from the well-known data-compression algorithm, AZTEC, which is also a real-time algorithm. It is found that under the same bit rate, a considerable improvement of root-mean-square error (RMS_err) can be achieved by employing the proposed AZTDIS algorithm. An average value of RMS_err of 9.715 can be achieved even at an average bit rate of 0.543 bits per sample by employing AZTDIS. By tuning the allowed maximal error of AZTDIS such that it has similar bit rate to AZTEC, the average value of RMS_err achieved by AZTDIS is 5.554 while the average value of RMS_err achieved by AZTEC under the same bit rate is 19.368.</p></div>","PeriodicalId":75992,"journal":{"name":"Journal of biomedical engineering","volume":"15 6","pages":"Pages 510-515"},"PeriodicalIF":0.0,"publicationDate":"1993-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0141-5425(93)90067-9","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"19265107","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}