Journal of biomedical engineering最新文献

{"title":"Flow studies on atriopulmonary and cavopulmonary connections of the Fontan operations for congenital heart defects","authors":"H.T. Low ,&nbsp;Y.T. Chew ,&nbsp;C.N. Lee","doi":"10.1016/0141-5425(93)90006-K","DOIUrl":"10.1016/0141-5425(93)90006-K","url":null,"abstract":"<div><p>A comparative flow study has been conducted on two configurations of the Fontan operations for congenital heart defects in which the right ventricle is by-passed. The study was made on rigid <em>in vitro</em> models of the atriopulmonary and cavopulmonary connections under steady-flow conditions. It involved using pressure and flow measurements to determine the pressure-drop coefficient, pressure-energy-loss coefficient and total-energy-loss coefficient. The cavopulmonary model was found to have much lower flow losses compared to the atriopulmonary model, especially at flow rates about 5 l min⁻¹</p></div>","PeriodicalId":75992,"journal":{"name":"Journal of biomedical engineering","volume":"15 4","pages":"Pages 303-307"},"PeriodicalIF":0.0,"publicationDate":"1993-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0141-5425(93)90006-K","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"18692627","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":"Novel monochromatic optical density meter","authors":"J. Dumville ,&nbsp;D.J. Clark ,&nbsp;P.O. Byrne","doi":"10.1016/0141-5425(93)90007-L","DOIUrl":"10.1016/0141-5425(93)90007-L","url":null,"abstract":"<div><p>A novel monochromatic optical density meter is described for use with radiographic films. The principles of the instrument are outlined together with a brief description of the construction of a prototype model. The calibration of the meter shows high accuracy (<em>r</em> = 0.9999) in the optical density range 0–1.5 OD when compared to standard neutral density filters.</p></div>","PeriodicalId":75992,"journal":{"name":"Journal of biomedical engineering","volume":"15 4","pages":"Pages 308-310"},"PeriodicalIF":0.0,"publicationDate":"1993-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0141-5425(93)90007-L","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"19346915","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":"A three-dimensional anatomical model of the human patello-femoral joint, for the determination of patello-femoral motions and contact characteristics","authors":"M.S. Hefzy,&nbsp;H. Yang","doi":"10.1016/0141-5425(93)90005-J","DOIUrl":"10.1016/0141-5425(93)90005-J","url":null,"abstract":"<div><p>The object of this study is to develop a three-dimensional mathematical model of the patello-femoral joint, which is modelled as two rigid bodies representing a moving patella and a fixed femur. Two-point contact was assumed between the femur and patella at the medial and lateral sides and in the analysis, the femoral and patellar articular surfaces were mathematically represented using Coons' bicubic surface patches. Model equations include six equilibrium equations and eleven constraints: six contact conditions, four geometric compatibility conditions, and the condition of a rigid patellar ligament; the model required the solution of a system of 17 nonlinear equations in 17 unknowns, its response describing the six-degress-of-freedom patellar motions and the forces acting on the patella. Patellar motions are described by six motion parameters representing the translations and rotations of the patella with respect to the femur. The forces acting on the patella include the medial and lateral component of patello-femoral contact and the patellar ligament force, all of which were represented as ratios to the quadriceps tendon force. The model response also includes the locations of the medial and lateral contact points on the femur and the patella. A graphical display of its response was produced in order to visualize better the motion of the components of the extensor mechanism.</p><p>Model calculations show good agreement with experimental results available from the literature. The patella was found to move distally and posteriorly on the femoral condyles as the knee was flexed from full extension. Results indicate that the relative orientation of the patellar ligament with respect to the patella remains unchanged during this motion. The model also predicts a patellar flexion which always lagged knee flexion.</p><p>Our calculations show that as the angle of knee flexion increased, the lateral contact point moved distally on the femur without moving significantly either medially or laterally. The medial contact point also moved distally on the femur but moved medially from full extension to about 40° of knee flexion, then laterally as the knee flexion angle increased. The lateral contact point on the patella did not change significantly in the medial and lateral direction as the knee was flexed; however, this point moved proximally toward the basis of the patella with knee flexion. The medial contact point also moved proximally on the patella with knee flexion, and in a similar manner the medial contact point on the patella moved distally with flexion from full extension to about 40° of flexion. However, as the angle of flexion increased, the medial contact point did not move significantly in the medial-lateral direction.</p><p>Model calculations also show that during the simulated knee extension exercise, the ratio of the force in the patellar ligament to the force in the quadriceps tendon remains almost unchanged for the first 30° of kne","PeriodicalId":75992,"journal":{"name":"Journal of biomedical engineering","volume":"15 4","pages":"Pages 289-302"},"PeriodicalIF":0.0,"publicationDate":"1993-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0141-5425(93)90005-J","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"19346914","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":"Sustained slow sinus rhythm entrained by retrograde atrial impulses","authors":"K. Izumi ,&nbsp;P.D. Stein ,&nbsp;S. Goldstein","doi":"10.1016/0141-5425(93)90015-Q","DOIUrl":"10.1016/0141-5425(93)90015-Q","url":null,"abstract":"<div><p>Sustained slow sinus rhythm due to a returning cycle after a premature atrial P wave is described. It seems possible to consider a model of the forced vibration in a spring-mass system or resonant electric circuit of an alternating current series element containing resistance <em>R</em>, inductance <em>L</em>, and capacitance <em>C</em> as a quantitative approach to describing the slow sinus rhythm. The differential equation expressing cardiac resonant oscillation has for the case <span><math><mtext>R = 500Ω</mtext></math></span> the form <span><math><mtext>178(</mtext><mtext>d</mtext><msup><mi></mi><mn>2</mn></msup><mtext>X</mtext><mtext>d</mtext><mtext>t</mtext><msup><mi></mi><mn>2</mn></msup><mtext>) + 500(</mtext><mtext>d</mtext><mtext>X</mtext><mtext>d</mtext><mtext>t</mtext><mtext>) + 5600X = 4490 cos 3.57</mtext><mtext>t</mtext></math></span>, where <em>X</em> is 100 <em>q</em>, where <em>q</em> is the capacitor charge. By solving the equation of this special case, we obtained an effective voltage and current of 0.84 V and 1.68 mA, respectively. Determination of cardiac electrical activity by this method was considered to be useful, and may have practical applications in solving problems of nearly linear resonance in vital phenomena. This is the first paper on applying a linear second order differential equation to describing a frequency response modelling of slow sinus rhythm due to entrainment by the retrograde atrial impulses.</p></div>","PeriodicalId":75992,"journal":{"name":"Journal of biomedical engineering","volume":"15 4","pages":"Pages 349-352"},"PeriodicalIF":0.0,"publicationDate":"1993-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0141-5425(93)90015-Q","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"19347539","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":"Glottal fry and voice disguise: a case study in forensic phonetics","authors":"A. Hirson ,&nbsp;M. Duckworth","doi":"10.1016/0141-5425(93)90115-F","DOIUrl":"10.1016/0141-5425(93)90115-F","url":null,"abstract":"<div><p>In recent legal proceedings, forensic phoneticians were called upon to analyse a tape-recorded message intended for the blackmail of a bank manager following the kidnap of his wife. The brief was to establish the likelihood that the tape recording may have been made by any one of three suspects, samples of whose speech were also made available. The comparison was greatly complicated by voice disguise employed by the speaker who recorded the kidnap tape. This disguise comprised a form of phonation described phonetically as ‘glottal fry’ or vocal ‘creak’. This form of phonation occurs normally in normal speech, but it has received most attention in relation to voice pathologies. On the other hand there are few references to its use as a form of voice disguise. This paper discusses the nature of the creak, and examines its effectiveness as voice disguise. In addition, a method is described for speaker identification regardless of the disguise. Results indicate that trained listeners without repeated presentations or instrumentation are able to match speakers with 65% accuracy when one voice is creaky, compared with 90% accuracy for undisguised voices. Using a Euclidean metric to compare the power spectra of the [s] sound, we find that creaky disguised voices may be correctly matched with the undisguised voice of the same speaker (9 distracters) in 5 cases out of 10. However, when the computer's task is made more similar to the perceptual task, selecting one speaker out of two, it achieves an accuracy of 81%. Implications for forensic phonetics are discussed.</p></div>","PeriodicalId":75992,"journal":{"name":"Journal of biomedical engineering","volume":"15 3","pages":"Pages 193-200"},"PeriodicalIF":0.0,"publicationDate":"1993-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0141-5425(93)90115-F","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"19308555","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":"Predicting the leakage performance of bodyworn disposable incontinence pads using laboratory tests","authors":"A.M. Cottenden,&nbsp;D.J. Ledger","doi":"10.1016/0141-5425(93)90117-H","DOIUrl":"10.1016/0141-5425(93)90117-H","url":null,"abstract":"<div><p>An international multi-centre project (The ISO Pad Leakage Project) was conducted to study the leakage performance of large bodyworn incontinence pads for heavily incontinent users and to create international standards for measuring their absorption capacities in the laboratory. This was achieved by recruiting 13 user test centres through which over 100 incontinent subjects tested each of six different products (each in three different sizes) for a period of about a week to a common protocol. Over 10 000 used pads were collected and weighed and the severity of leakage from each of them recorded. Correlations were sought between these data and the results from some 50 technical tests performed in a total of 16 technical test centres in order to discover the impact of different technical parameters on clinical pad performance. It was found that at low urine weights (less than 50 g, say) pad shaping was the most important predictor of pad leakage performance: shaped pads leaked less. With increasing urine weight, absorption capacity and absorption time increased in importance until at 350 g of urine these two parameters and shaping were of about equal significance: shaped pads with high absorption capacity and fast absorption time leaked least. A second series of analyses identified two absorption capacity tests which produced data correlating well with the overall leakage performance of pads, considering all urine weights together. Both tests were checked for repeatability (precision within laboratories) and reproducibility (precision between laboratories) and have been written up as working draft standards. In due course, either or both of them should be adopted as International Standards for measuring the absorption capacity of pads for heavily incontinent users. A second, similar project (ISO Pad Leakage Project 2) has begun. It focuses on small pads for lightly incontinent ambulatory women.</p></div>","PeriodicalId":75992,"journal":{"name":"Journal of biomedical engineering","volume":"15 3","pages":"Pages 212-220"},"PeriodicalIF":0.0,"publicationDate":"1993-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0141-5425(93)90117-H","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"19308557","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":"Method for single-trial recordings of somatosensory evoked potentials","authors":"Shigeto Nishida ,&nbsp;Masatoshi Nakamura ,&nbsp;Hiroshi Shibasaki","doi":"10.1016/0141-5425(93)90124-H","DOIUrl":"10.1016/0141-5425(93)90124-H","url":null,"abstract":"<div><p>Evoked potentials (EPs) in response to stimuli are recorded from a human scalp contaminated with noise. To improve the signal-to-noise ratio, averaging methods have been widely used for the recorded data. However, when the waveforms of EP for each stimulus are not identical, the average waveform of the EP deteriorates. Variation of the EP waveform to each stimulus itself is important information for the EP. In this paper, a recording method for single somatosensory evoked potential (SEP) waveform is proposed, in which three kinds of band-pass filters were selectively used during three specific time sectors for each interstimulus interval. For the late section of the interval, an EEG waveform prediction method was applied to eliminate contaminated alpha rhythm components. By using the proposed method, we were successful in detecting the single SEP waveform.</p></div>","PeriodicalId":75992,"journal":{"name":"Journal of biomedical engineering","volume":"15 3","pages":"Pages 257-262"},"PeriodicalIF":0.0,"publicationDate":"1993-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0141-5425(93)90124-H","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"19308440","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":"Mean residence time in multicompartmental models with time delays","authors":"Y. Plusquellec ,&nbsp;G. Houin","doi":"10.1016/0141-5425(93)90121-E","DOIUrl":"10.1016/0141-5425(93)90121-E","url":null,"abstract":"<div><p>Calculation of the mean residence time (MRT) of a drug in a stationary compartmental model is classically carried out from several expressions. Nevertheless, one or more time delays between compartments modify the mean residence times. It is the aim of this paper to propose a general method for MRT calculations, in any <em>n</em>-compartmental models which may include time delays. As examples, catenary and mammillary models are considered.</p></div>","PeriodicalId":75992,"journal":{"name":"Journal of biomedical engineering","volume":"15 3","pages":"Pages 240-246"},"PeriodicalIF":0.0,"publicationDate":"1993-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0141-5425(93)90121-E","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"19308561","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":"A real-time gesture recognizer based on dynamic programming","authors":"A.I. Tew,&nbsp;C.J. Gray","doi":"10.1016/0141-5425(93)90113-D","DOIUrl":"10.1016/0141-5425(93)90113-D","url":null,"abstract":"<div><p>Coded gestures are physical movements to which precise meanings have been attached. Their use with an electronic pointing device potentially increases the power of the pointer by allowing several distinct control functions to be incorporated. The formation of a coded gesture is invariably subject to distortions which make its automatic recognition difficult. After particular consideration of three techniques, a dynamic programming algorithm was developed and was used in the design of a real-time gesture recognizer that allows mouse-driven software to be operated purely by means of an electronic pointer. The decision was taken to implement the gesture recognizer using a widely available, obsolescent microcomputer in order to keep down costs. Despite the inevitable technical compromises in this approach, results of preliminary trials using 10 normal subjects show an average gesture recognition rate of 98.3% and a gesture confusion rate of only 0.4%.</p></div>","PeriodicalId":75992,"journal":{"name":"Journal of biomedical engineering","volume":"15 3","pages":"Pages 181-187"},"PeriodicalIF":0.0,"publicationDate":"1993-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0141-5425(93)90113-D","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"19307223","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":"Cyclic model of respiration applied to asymmetrical ventilation and periodic breathing","authors":"B. Vielle,&nbsp;G. Chauvet","doi":"10.1016/0141-5425(93)90123-G","DOIUrl":"10.1016/0141-5425(93)90123-G","url":null,"abstract":"<div><p>A model taking into account the cyclic character of respiration in humans is developed using two classical simplifications: CO₂ is the only respiratory gas involved; and respiration is regulated only by a CO₂ linear controller. The model is used to investigate two important clinical aspects of respiratory disease: asymmetrical ventilation and periodic breathing. We show that asymmetry in ventilation significantly influences the time course of the CO₂ partial pressure in the expired alveolar air at the mouth and the elimination of CO₂ through the lungs. Furthermore, the CO₂ controller delay plays a major role in periodic breathing.</p></div>","PeriodicalId":75992,"journal":{"name":"Journal of biomedical engineering","volume":"15 3","pages":"Pages 251-256"},"PeriodicalIF":0.0,"publicationDate":"1993-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0141-5425(93)90123-G","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"19308439","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}