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Biomedical subjects

J H Pei

Publications and source records attributed to J H Pei.

3 recordsLinked to original sources

Observation of the surface stress induced in microcantilevers by electrochemical redox processes.

The potential-induced surface stress of a solid electrode was investigated in an electrochemical cell. Gold-coated atomic force microscopy microcantilevers were used as working electrodes to measure the current-potential response (by cyclic voltammetry) and simultaneous bending characteristics in solutions of NaNO3 and K3Fe(CN)6/NaNO3. The observed changes of differential surface stress at a microcantilever electrode were attributed to electrochemical-potential-induced changes in surface charge density, ion adsorption/desorption, and electron transfer across the electrode surface. The potential dependent change in stress shows promise for the study of microscopic properties at the solid-electrolyte interface.

Journal Article↗

Xinyinqin: a computer-based heart sound simulator.

"Xinyinqin" is the Chinese phoneticized name of the Heart Sound Simulator (HSS). The "qin" in "Xinyinqin" is the Chinese name of a category of musical instruments, which means that the operation of HSS is very convenient--like playing an electric piano with the keys. HSS is connected to the GAME I/O of an Apple microcomputer. The generation of sound is controlled by a program. Xinyinqin is used as a teaching aid of Diagnostics. It has been applied in teaching for three years. In this demonstration we will introduce the following functions of HSS: 1) The main program has two modules. The first one is the heart auscultation training module. HSS can output a heart sound selected by the student. Another program module is used to test the student's learning condition. The computer can randomly simulate a certain heart sound and ask the student to name it. The computer gives the student's answer an assessment: "correct" or "incorrect." When the answer is incorrect, the computer will output that heart sound again for the student to listen to; this process is repeated until she correctly identifies it. 2) The program is convenient to use and easy to control. By pressing the S key, it is able to output a slow heart rate until the student can clearly identify the rhythm. The heart rate, like the actual rate of a patient, can then be restored by hitting any key. By pressing the SPACE BAR, the heart sound output can be stopped to allow the teacher to explain something to the student. The teacher can resume playing the heart sound again by hitting any key; she can also change the content of the training by hitting RETURN key. In the future, we plan to simulate more heart sounds and incorporate relevant graphs.

Computer Simulation↗

Enormous knowledge base of disease diagnosis criteria.

One of the problems in the development of the medical knowledge systems is the limitations of the system's knowledge. It is a common expectation to increase the number of diseases contained in a system. Using a high density knowledge representation method designed by us, we have developed the Enormous Knowledge Base of Disease Diagnosis Criteria (EKBDDC). It contains diagnostic criteria of 1,001 diagnostic entities and describes nearly 4,000 items of diagnostic indicators. It is the core of a huge medical project--the Electronic-Brain Medical Erudite (EBME). This enormous knowledge base was implemented initially on a low-cost popular microcomputer, which can aid in the prompting of typical disease and in teaching of diagnosis. The knowledge base is easy to expand. One of the main goals of EKBDDC is to increase the number of diseases included in it as far as possible using a low-cost computer with a comparatively small storage capacity. For this, we have designed a high density knowledge representation method. Criteria of various diagnostic entities are respectively stored in different records of the knowledge base. Each diagnostic entity corresponds to a diagnostic criterion data set; each data set consists of some diagnostic criterion data values (Table 1); each data is composed of two parts: integer and decimal; the integral part is the coding number of the given diagnostic information, and the decimal part is the diagnostic value of this information to the disease indicated by corresponding record number. For example, 75.02: the integer 75 is the coding number of "hemorrhagic skin rash"; the decimal 0.02 is the diagnostic value of this manifestation for diagnosing allergic purpura. TABULAR DATA, SEE PUBLISHED ABSTRACT. The algebraic sum method, a special form of the weighted summation, is adopted as mathematical model. In EKBDDC, the diagnostic values, which represent the significance of the disease manifestations for diagnosing corresponding diseases, were determined empirically. It is of a great economical, practical, and technical significance to realize enormous knowledge bases of disease diagnosis criteria on a low-cost popular microcomputer. This is beneficial for the developing countries to popularize medical informatics. To create the enormous international computer-aided diagnosis system, one may jointly develop the unified modules of disease diagnosis criteria used to "inlay" relevant computer-aided diagnosis systems. It is just like assembling a house using prefabricated panels.

Artificial Intelligence↗