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Controlled mechanized trepan. 控制机械化钻孔机。
Journal of bioengineering Pub Date : 1978-04-01
J Kam, E M Goldratt, Y R Barishak, R Stein
{"title":"Controlled mechanized trepan.","authors":"J Kam,&nbsp;E M Goldratt,&nbsp;Y R Barishak,&nbsp;R Stein","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>A mechanized trepan is described whose cutting action is halted automatically when the trepan's cutting edge reaches the last 0.03 mm. tissue layer of the cornea. The automatic half of both the motor which advances the trepan as well as the second motor which rotates the trepan is triggered by the sudden change in electrical resistance between the trepan and the patient's internal body fluid, at the final stage of penetration. This automatic feature eliminates the danger of inadvertant damage to the inner structures of the eye.</p>","PeriodicalId":75990,"journal":{"name":"Journal of bioengineering","volume":"2 1-2","pages":"21-6"},"PeriodicalIF":0.0,"publicationDate":"1978-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"11564880","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: 0
Limitations of bandwidth compression hearing aids applied to the voiced portion of speech. 带宽压缩助听器应用于语音浊音部分的局限性。
Journal of bioengineering Pub Date : 1978-04-01
S G Knorr
{"title":"Limitations of bandwidth compression hearing aids applied to the voiced portion of speech.","authors":"S G Knorr","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>Numerous speech processing techniques have been applied to assist hearing-impaired subjects with extreme high-frequency hearing losses who can be helped only to a limited degree with conventional hearing aids. The results of providing this class of deaf subjects with a speech encoding hearing aid, which is able to reproduce intelligible speech for their particular needs, have generally been disappointing. There are at least four problems related to bandwidth compression applied to the voiced portion of speech: (1) the problem of pitch extraction in real time; (2) pitch extraction under realistic listening conditions, i.e. when competing speech and noise sources are present; (3) an insufficient data base for successful compression of voiced speech; and (4) the introduction of undesirable spectral energies in the bandwidth-compressed signal, due to the compression process itself. Experiments seem to indicate that voiced speech segments bandwidth limited to f = 1000 Hz, even at a loss of higher formant frequencies, is in most instances superior in intelligibility compared to bandwidth-compressed voiced speech segments of the same bandwidth, even if pitch can be extracted with no error. With the added complexity of real-time pitch extraction which has to function in actual listening conditions, it is doubtful that a speech encoding hearing aid, based on bandwidth compression on the voiced portion of speech, could be successfully implemented. However, if bandwidth compression is applied to the unvoiced portions of speech only, the above limitations can be overcome (1).</p>","PeriodicalId":75990,"journal":{"name":"Journal of bioengineering","volume":"2 1-2","pages":"47-57"},"PeriodicalIF":0.0,"publicationDate":"1978-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"11882365","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: 0
A self-transmitting surface acoustic wave (SAW) pressure transducer. 一种自发射表面声波(SAW)压力传感器。
Journal of bioengineering Pub Date : 1978-04-01
P Das, C Lanzl
{"title":"A self-transmitting surface acoustic wave (SAW) pressure transducer.","authors":"P Das,&nbsp;C Lanzl","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>We have developed a small, pressure-sensitive device using SAW oscillators, which is capable of being implanted and transmitting a signal several hundred feet. This paper presents the device and its prototypes, and data from the laboratory and live subjects.</p>","PeriodicalId":75990,"journal":{"name":"Journal of bioengineering","volume":"2 1-2","pages":"27-32"},"PeriodicalIF":0.0,"publicationDate":"1978-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"11882461","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: 0
Adsorption of collagen on model hydrophobic surfaces. 胶原蛋白在模型疏水表面的吸附。
Journal of bioengineering Pub Date : 1978-04-01
R D Bagnall
{"title":"Adsorption of collagen on model hydrophobic surfaces.","authors":"R D Bagnall","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>The change in interfacial tension with time for rat-tail tendon collagen adsorbing at the air, methylene iodide and isooctane interfaces has been followed by the pendant drop technique as a model for hydrophobic biomaterials. It is shown that the surface activity of tropocollagen at these three interfaces is less than that of albumin, gamma-globulin, serum of plasma, so that displacement of a preadsorbed plasma protein layer by tropocollagen molecules is energetically unfavourable and unlikely to occur. It is proposed that this may be one reason for the lack of interaction between hydrophobic soft tissue implants and their tissue capsules. It is then speculated that such interaction may require the development of biomaterials with a specific affinity for connective tissue components.</p>","PeriodicalId":75990,"journal":{"name":"Journal of bioengineering","volume":"2 1-2","pages":"69-78"},"PeriodicalIF":0.0,"publicationDate":"1978-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"11882368","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: 0
An analytical approach to the determination of optimal phasing for external counterpulsation. 一种确定外部反脉冲最佳相位的解析方法。
Journal of bioengineering Pub Date : 1978-04-01
J Lin, J C Hui, W C Birtwell, H S Soroff
{"title":"An analytical approach to the determination of optimal phasing for external counterpulsation.","authors":"J Lin,&nbsp;J C Hui,&nbsp;W C Birtwell,&nbsp;H S Soroff","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>An inhomogeneous linear one-dimensional mathematical model is constructed as a conceptual approach to the study of the effects of External Counterpulsation (ECP) on the pressure and flow at the root of the aorta. The optimal operation of ECP is defined by two conditions: (1) minimization of the mean systolic pressure; and (b) maximization of the ratio of diastolic area over systolic area under the total pressure curve. The phase shift of the external pressure is determined so as to satisfy these two requirements. It is demonstrated within our approximation that with a given magnitude of external pressure, the phase shifts that satisfy these two requirements are the same. These phase shifts are linear functions of the systolic fraction of the total cardiac period, and depend on the time for the external wave to travel from the site of application up the vascular bed to the root of the aorta, plus the reflection contributions. Even though these results are derived from a simple model far from the complexity of the actual vasculature, the basic concepts would remain valid even if more complex mathematical treatments would have been used.</p>","PeriodicalId":75990,"journal":{"name":"Journal of bioengineering","volume":"2 1-2","pages":"167-75"},"PeriodicalIF":0.0,"publicationDate":"1978-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"11882460","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: 0
Diffusion of fluoride ions in dental enamel at pH 7. pH值为7时氟离子在牙釉质中的扩散。
Journal of bioengineering Pub Date : 1978-04-01
G J Flim, Z Kolar, J Arends
{"title":"Diffusion of fluoride ions in dental enamel at pH 7.","authors":"G J Flim,&nbsp;Z Kolar,&nbsp;J Arends","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>The penetration and uptake of both radioactive (18F) and stable fluoride (19F) in bovine enamel were investigated. Buffered pH 7 NaF solutions were employed. Penetration profiles of both 18F and 19F in enamel were determined by using a sectioning technique. 18F and 19F concentrations decreased exponentially with increasing penetration distance. The uptake of 18F in enamel can be described by a power function of the immersion time, with an average power of 0.76. The results agree reasonably with our previously published theoretical model for the diffusion in enamel, based on simultaneous diffusion in enamel pores and in the hydroxyapatite crystallites. The diffusion coefficients of fluoride ions in enamel obtained from the application of the model to the results presented here, were: D = 0.9 x 10(-17) cm2/s in the crystallites and D' = 3.3 x 10(-10) cm2/s in the enamel pores. An average penetration depth of fluoride ions at pH 7.0 of 8 micron in 4 hours has been calculated.</p>","PeriodicalId":75990,"journal":{"name":"Journal of bioengineering","volume":"2 1-2","pages":"93-102"},"PeriodicalIF":0.0,"publicationDate":"1978-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"11251401","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: 0
An electronic frequency shifting stethoscope for heart sounds. 一种用于检测心音的电子移频听诊器。
Journal of bioengineering Pub Date : 1978-04-01
G A Holloway, D Watkins
{"title":"An electronic frequency shifting stethoscope for heart sounds.","authors":"G A Holloway,&nbsp;D Watkins","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>The predominating energy in the normal heart sounds has been found to be at frequencies below the normal hearing threshold. Because it was felt that significant clinical information was likely to be present at those frequencies, an instrument was designed and fabricated which would frequency shift the entire heart sound into the middle of the auditory frequency range. Clinical testing showed that changes were readily detected in a monitoring situation, and that use of the instrument was both simple and easy to learn.</p>","PeriodicalId":75990,"journal":{"name":"Journal of bioengineering","volume":"2 1-2","pages":"59-64"},"PeriodicalIF":0.0,"publicationDate":"1978-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"11882366","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: 0
An electrophysiological approach to neural augmentation implantation for the control of pain. 神经增强植入控制疼痛的电生理方法。
Journal of bioengineering Pub Date : 1978-04-01
J B Mullen, C F Walker, B S Nashold
{"title":"An electrophysiological approach to neural augmentation implantation for the control of pain.","authors":"J B Mullen,&nbsp;C F Walker,&nbsp;B S Nashold","doi":"","DOIUrl":"","url":null,"abstract":"","PeriodicalId":75990,"journal":{"name":"Journal of bioengineering","volume":"2 1-2","pages":"65-7"},"PeriodicalIF":0.0,"publicationDate":"1978-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"11882367","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: 0
Use of glutaraldehyde and formaldehyde to process tissue heart valves. 使用戊二醛和甲醛处理组织心脏瓣膜。
Journal of bioengineering Pub Date : 1978-04-01
E A Woodroof
{"title":"Use of glutaraldehyde and formaldehyde to process tissue heart valves.","authors":"E A Woodroof","doi":"","DOIUrl":"","url":null,"abstract":"","PeriodicalId":75990,"journal":{"name":"Journal of bioengineering","volume":"2 1-2","pages":"1-9"},"PeriodicalIF":0.0,"publicationDate":"1978-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"11318689","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: 0
Data acquisition system for body surface potential mapping. 体表电位测绘数据采集系统。
Journal of bioengineering Pub Date : 1978-04-01
W H Ko, B P Bergmann, R Plonsey
{"title":"Data acquisition system for body surface potential mapping.","authors":"W H Ko,&nbsp;B P Bergmann,&nbsp;R Plonsey","doi":"","DOIUrl":"","url":null,"abstract":"","PeriodicalId":75990,"journal":{"name":"Journal of bioengineering","volume":"2 1-2","pages":"33-46"},"PeriodicalIF":0.0,"publicationDate":"1978-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"11882364","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: 0
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