Gerald E. Miller

A multiple disk centrifugal pump as a blood flow device

A study of a multiple-disk, shear force, valveless centrifugal pump to determine its suitability as a blood flow device is discussed. A pulsatile version of the Tesla viscous flow turbine was designed by modifying the original steady flow pump concept to produce physiological pressures and flows with the aid of controlling circuitry. Pressures and flows from this pump were compared to a Harvard Apparatus pulsatile piston pump. Both pumps were connected to an artificial circulatory system. Frequency and systolic duration were varied over a range of physiological conditions for both pumps. The results indicated that the Tesla pump, operating in a pulsatile mode, is capable of producing physiologic pressures and flows similar to those produced by the Harvard pump and other pulsatile blood pumps.<<ETX>>

Computer simulation of human mitral valve mechanics and motion

The human mitral valve is the left atrio-ventricular valve which is composed of several components including leaflets, chordae tendineae, papillary muscles, and the valve annulus. Any or all of these components may fail and contribute to various valvular diseases including mitral regurgitation and mitral valve prolapse. A computer simulation of mitral valve mechanics and motion was written in BASIC for micro-computers. This program allows valvular geometry and biomechanical parameters to be varied and records time varying motion of the valve and all components during systole including a graphic display of the valve leaflets.

PULMONOLOGIST: A computer-based diagnosis system for pulmonary diseases

PULMONOLOGIST is a prototype expert system designed as a decision-making aid for physicians in providing accurate diagnosis and treatment of lung diseases. Disease information in the system has been encoded in the form of rules and schemata. The system has been developed using the expert system building tool ART (Automated Reasoning Tool) from Inference Corporation. This paper gives a brief introduction to the expert system concept, and includes a detailed description of the diagnosis system. This system will be tested against clinical data in future studies.

The relationship of cognitively induced anxiety and hand temperature reduction

Abstract The relationship between cognitively induced anxiety and hand temperature reduction in a nonclinical sample is explored. Forty female college students were randomly assigned to either an Anxiety Group or a Pleasant Group. Following a baseline period, individuals in the Anxiety Group discussed topics, in a time-controlled setting, which were anxiety-producing for them. Individuals in the Pleasant Group discussed topics of a pleasant nature. During these discussions, hand temperatures were recorded from the palmar surface of the third finger on the dominant hand. Data analysis indicated that hand temperature decreases were significant only in subjects discussing anxiety-producing topics.

Automated Correlation of Intravascular Ultrasound Images with Angiography

One limitation of intravascular ultrasound (IVUS) is the restriction to viewing one cross‐sectional image at a time. Computerized three‐dimensional reconstructions of IVUS images have been developed in an attempt to overcome this limitation. These algorithms, however, are limited by artifacts from catheter movements and rotation within large vessels. Consequently, this technique has been applied only to straight segments of small caliber vessels. Contrast angiography has long been the standard for vascular imaging. In order to take advantage of both contrast angiography and IVUS, we developed a computer procedure to automatically correlate IVUS images with their corresponding locations on contrast angiograms, and to display both images in a side by side format. Models of the aortic arch and aorto‐ileo‐femoral system were constructed with artificial plaques located at various sites. The models were filled with iodinated contrast media and radiographic images were obtained. Timed pull‐backs were performed in both models in order to obtain sets of serial cross‐sectional images. For each data set, a digitized set of 75 serial IVUS images and model angiographic images were loaded in the computer procedure. We then correlated at least one IVUS image containing a known landmark with its position on the model angiogram. The procedure then automatically displayed sequential ultrasound images along with their corresponding positions on the reference angiogram. We analyzed the error of this algorithm as a function of the number of correlation points used. The maximum error was 4 mm over a total pullback distance of 130 mm (relative error of 3%). This algorithm was subsequently used to correlate IVUS images obtained from the aortic arch of a patient with their corresponding positions on an aortogram. Our results demonstrate that computer‐based correlation of IVUS images with their corresponding positions on angiograms is accurate, may enhance the use of IVUS to assess vascular pathology, and provides an alternative to three‐dimensional reconstructions.

Cerebrospinal Impedance Response to Induced Epileptic Activit

Impedance levels in the cerebrospinal fluid in cats were measured prior to and during epileptic seizures. Seizures were induced with an intramuscular injection of penicillin during general anesthesia. Impedance levels were elevated to twice the threshold value up to 15 min prior to the onset of seizure activity. Seizures were monitored with a depth EEG electrode. The detection of a significant measurable preseizure event will aid in the development of an early warning detector to alert epileptics of an impending seizure. The millions of epileptics who cannot be treated surgically or pharmaceutically would not have to severely restrict their activities, as they would have ample warning of the onset of a seizure. This study is undertaken to develop the detection method to use in such a device.

Neural network control for intelligent end effector of manipulators via proximity sensing

The authors develop a technique using an artificial neural network system for the intelligent control of a robot manipulator (e.g. Unimation PUMA 560) that can grasp objects dexterously with active optical proximity sensors. Multi-layer neural networks are presented to process the sensor information for grasping objects dexterously via iterative learning of the network. The sensory system uses a transmission (beam-block) sensing mode and a reflection sensing mode. Complex nonlinear operations for processing the information can be performed easily by the artificial neural network, and total processing can be performed in real-time by using a DSP board (AT&T WE DSP32C, 49.152 MHz).<<ETX>>

Neural network control of intelligent end-effector for a rehabilitation robot

This paper will describe the development of a technique using an Artificial Neural Network system for the intelligent control of a rehabilitation robot that can grasp objects dexterously with active optical proximity sensors. Multi-layer neural networks are presented to process the sensor information for grasping objects dexterously via iterative learning of the network. Complex nonlinear operations for processing the information can be performed easily by the Artificial Neural Network and total processing can be performed in real-time by using a DSP system.

Artificial organs. Proceedings of the International Symposium on Artificial Organs, Biomedical Engineering, and Transplantation in Honor of the 75th Birthday of Willem J. Kolff

The Annals of Biomedical Engineering has initiated a book review series under its newly formed section dedicated to Professional Technical Service. The book review section will bring timely and informative reviews of new books in biomedical engineering to our readers. Additional book reviewers are needed to support this effort. If you would be willing to write an occasional review in exchange for a copy of the book, please send your name, address, phone number and areas of interest to: