Medical progress through technology最新文献_第3页

Color quantification in angioscopic video images. 血管镜视频图像的颜色定量。

Medical progress through technology Pub Date : 1995-01-01

J A Oomen, C J Slager, K G Lehmann, J C Schuurbiers, P W Serruys

引用次数: 0

Methodology for a medical expert system on fuzzy analog ganglionar lattices. Non-approximate reasoning with multiple antecendents of different relative importance and limited uncertainty. 基于模糊模拟神经节格的医学专家系统方法学。具有不同相对重要性和有限不确定性的多个先行词的非近似推理。

Medical progress through technology Pub Date : 1995-01-01

C A Holzmann, A Ehijo, C A Perez

{"title":"Methodology for a medical expert system on fuzzy analog ganglionar lattices. Non-approximate reasoning with multiple antecendents of different relative importance and limited uncertainty.","authors":"C A Holzmann, A Ehijo, C A Perez","doi":"","DOIUrl":"","url":null,"abstract":"This work presents an Expert System based on fuzzy analog ganglionar lattices. Its reasoning scheme is designed analogously to the expert's mental organization and it is realized on an (analog) operator called the ganglionar lattice. It is a connectionist system that uses the medical knowledge to define its architecture. The operator evokes some similarities to higher order neural networks and performs as the knowledge base and inference engine of the expert system, in a unified manner. A main feature of this operator is that it exhibits the variables corresponding to all intermediate concepts identified by the expert; this characteristic is shown to be most valuable for assessing, explicating and prospecting in medical applications. Further, it is capable of (i) evaluating a consequent for a variety of non-approximate reasonings with multiple antecendents of different relative importance under limited uncertainty; (ii) explicating the conclusions at different levels of abstraction to suit the user; and (iii) prospecting for the best 'a priori' sequence of unevaluated antecedents, from which to choose following tests. These procedures are based on the objective criterion of the consequent's uncertainty decrease (entropy). All results are produced in numerical form and may be translated into restricted natural language. A simple example of this technology is fully developed. Finally the method's potentials are discussed for future applications.","PeriodicalId":76136,"journal":{"name":"Medical progress through technology","volume":"21 3","pages":"147-58"},"PeriodicalIF":0.0,"publicationDate":"1995-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"19748520","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

EEG-based brain computer interface (BCI). Search for optimal electrode positions and frequency components. 基于脑电图的脑机接口。搜索最佳的电极位置和频率成分。

Medical progress through technology Pub Date : 1995-01-01

G Pfurtscheller, D Flotzinger, M Pregenzer, J R Wolpaw, D McFarland

引用次数: 0

Filtering properties of an adaptive trend operator and the application for determining the arterial blood velocity in retinal vessels. 自适应趋势算子的滤波特性及其在测定视网膜血管中动脉血流速度中的应用。

Medical progress through technology Pub Date : 1995-01-01

E Baresová, G Grieszbach, B Schack, W Vilser, C Bräuer-Burchardt, I Senff

引用次数: 0

The evolution of functional endoscopic sinus surgery in the Commonwealth of Virginia. 功能性内窥镜鼻窦手术在弗吉尼亚州的发展。

Medical progress through technology Pub Date : 1995-01-01

S D London, J C Wheeler, G C Zachmann, W P Glasheen, J L Colley, P H Poulterer, J A Bander, R F Edlich, C W Gross

引用次数: 0

Time-frequency spectral analysis of electric field plethysmography signals. 电场容积脉搏波信号的时频分析。

Medical progress through technology Pub Date : 1995-01-01

C Ruhsam, H Pfützner, P Nopp, H Nakesch, H Frais-Kölbl, W Marktl

{"title":"Time-frequency spectral analysis of electric field plethysmography signals.","authors":"C Ruhsam, H Pfützner, P Nopp, H Nakesch, H Frais-Kölbl, W Marktl","doi":"","DOIUrl":"","url":null,"abstract":"Cardiac activity contaminates respiratory electric field plethysmography (EFPG) signals, and vice versa, and is usually treated as an artefact. On the other hand, simultaneous information on respiration and cardiac activity is often required in clinical practice. Hence, we use time-frequency spectral analysis (TFSA) by means of the spectrogram (SG) to investigate the instantaneous cardio-respiratory information contained in EFPG-signals and show that it is a practical means of extracting this information out of a single EFPG-signal. Comparisons with a Wigner distribution reveal sufficient time-frequency resolution of the SG for detection of physiological events in EFPG-signals. SG-analysis indicates spectral peaks related to respiration and cardiac activity (depending on the electrode configuration, up to the third and fifth harmonic, respectively) and the possibility to detect respiratory sinus arrhythmia by means of EFPG-measurements. Intermodulation products cause overlaps of respiratory and cardiac spectra pointing out nonlinear relationships. Additionally, SG-analysis supplies essential information for the separation of EFPG-signals into respiratory and cardiac components, by means of filter techniques.","PeriodicalId":76136,"journal":{"name":"Medical progress through technology","volume":"21 1","pages":"17-28"},"PeriodicalIF":0.0,"publicationDate":"1995-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"18792700","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

The cochlear implant. A technology for the profoundly deaf. 人工耳蜗。一种专为聋人设计的技术。

Medical progress through technology Pub Date : 1995-01-01

A R Lea, D M Hailey

引用次数: 0

Electric field plethysmography signals of the human thorax as determined by a 2-D FE-model. 由二维有限元模型确定的人类胸腔的电场体积脉搏信号。

Medical progress through technology Pub Date : 1995-01-01

P Nopp, H Pfützner, K Bögl, H Nakesch, C Ruhsam

{"title":"Electric field plethysmography signals of the human thorax as determined by a 2-D FE-model.","authors":"P Nopp, H Pfützner, K Bögl, H Nakesch, C Ruhsam","doi":"","DOIUrl":"","url":null,"abstract":"Electric field plethysmography (EFPG) signals of the human thorax consist of a baseline component, a respiratory component and a cardiac component. This paper investigates to what extent a two-dimensional finite-element model of the human thorax can serve as a tool for signal prediction allowing for both optimisation of electrode position and effective signal interpretation. In the model inspiration is taken into account by decreasing lung conductivity. Modelling of cardiac activity involves heart geometry changes and lung conductivity increase. Comparison with experiments shows that the model is more effective for strip than spot electrodes for current injection. Modelling results suggest that the thorax behaves approximately as a homogeneous structure with an inspiratory conductivity increase of about 5%. Two electrode pairs are preferable for monitoring respiration in general. As cardiac activity involves two counter-acting signal sources in the thorax, optimum electrode position is obtained using four separated electrodes. However, recommendable positions for two electrode pairs are on the left sternal and right parasternal line. The investigation shows that in providing a proper modelling of respiration and cardiac activity, a 2-D model provides a practical tool for modelling EFPG signals with the cost of a few structural and systematical restrictions.","PeriodicalId":76136,"journal":{"name":"Medical progress through technology","volume":"21 3","pages":"135-45"},"PeriodicalIF":0.0,"publicationDate":"1995-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"19748516","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

New aspects in electrostimulation of the heart. 心脏电刺激的新进展。

Medical progress through technology Pub Date : 1995-01-01

M Schaldach

{"title":"New aspects in electrostimulation of the heart.","authors":"M Schaldach","doi":"","DOIUrl":"","url":null,"abstract":"The interaction of the autonomic nervous system (ANS) and the heart is characterized by a new interdisciplinary field known as neurocardiology which presents the newest strategy for electro-cardiostimulation. In this context, the reestablishment of chronotropy with physiological, closed-loop pacing, as well as the prevention and treatment of a malignant arrhythmia by ANS modulation, is of the highest priority. The main objective toward this goal consists of appropriate monitoring of the autonomic balance and stimulation, respectively, so that neuromodulation of the cardiac efferents can be established. The electrode, as a sensor and an actuator, with its interface on the cellular level becomes of essential importance. The electrode-myocardium interface is determined by the structure of the Helmholtz double layer with regard to its physical, electrochemical, and physiological behavior. The transportation of electrons across the boundary, as well as the electro-chemical reactions determining the biocompatibility of the interface, can be improved by the microstructure of the solid component by creating a fractal surface coating with titanium-nitride or iridium. Experimental and clinical results have demonstrated that the fractal structure ensures negligible polarization as well as improved detection performance, thus, detecting the evoked response of the myocardial cells makes it possible to monitor the neural response of the myocardium as a consequence of a superimposed chronotropic disturbance. The stimulation electrode also monitors the sympathetic activity extracted from intracardiac impedance measurements, thereby providing a new principle of rate adaptation in which the pacemaker is an integral part of the ANS, reestablishing normal chronotropy. Further advantages of the improved electrode interface performance open new aspects in the treatment and prevention of tachyarrhythmia, and in the follow-up of transplanted hearts for the prevention of the rejection processes.","PeriodicalId":76136,"journal":{"name":"Medical progress through technology","volume":"21 1","pages":"1-16"},"PeriodicalIF":0.0,"publicationDate":"1995-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"18792698","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

Electrical impedance for estimation of irritation in oral mucosa and skin. 估计口腔黏膜和皮肤刺激的电阻抗。

Medical progress through technology Pub Date : 1995-01-01

S Ollmar, A Eek, F Sundström, L Emtestam

引用次数: 0