The median-effect equation derived from the mass-action law principle at equilibrium-steady state via mathematical induction and deduction for different reaction sequences and mechanisms and different types of inhibition has been shown to be the unified theory for the Michaelis-Menten equation, Hill equation, Henderson-Hasselbalch equation, and Scatchard equation. It is shown that dose and effect are interchangeable via defined parameters. This general equation for the single drug effect has been extended to the multiple drug effect equation for n drugs. These equations provide the theoretical basis for the combination index (CI)-isobologram equation that allows quantitative determination of drug interactions, where CI 1 indicate synergism, additive effect, and antagonism, respectively. Based on these algorithms, computer software has been developed to allow automated simulation of synergism and antagonism at all dose or effect levels. It displays the dose-effect curve, median-effect plot, combination index plot, isobologram, dose-reduction index plot, and polygonogram for in vitro or in vivo studies. This theoretical development, experimental design, and computerized data analysis have facilitated dose-effect analysis for single drug evaluation or carcinogen and radiation risk assessment, as well as for drug or other entity combinations in a vast field of disciplines of biomedical sciences. In this review, selected examples of applications are given, and step-by-step examples of experimental designs and real data analysis are also illustrated. The merging of the mass-action law principle with mathematical induction-deduction has been proven to be a unique and effective scientific method for general theory development. The median-effect principle and its mass-action law based computer software are gaining increased applications in biomedical sciences, from how to effectively evaluate a single compound or entity to how to beneficially use multiple drugs or modalities in combination therapies.

http://www.protocol-online.org/forums/uploads/monthly_09_2010/post-8165-008503000%201284677034.ipb

Theoretical Basis, Experimental Design, and Computerized Simulation of Synergism and Antagonism in Drug Combination Studies

This paper describes the concept of adaptive noise cancelling, an alternative method of estimating signals corrupted by additive noise or interference. The method uses a "primary" input containing the corrupted signal and a "reference" input containing noise correlated in some unknown way with the primary noise. The reference input is adaptively filtered and subtracted from the primary input to obtain the signal estimate. Adaptive filtering before subtraction allows the treatment of inputs that are deterministic or stochastic, stationary or time variable. Wiener solutions are developed to describe asymptotic adaptive performance and output signal-to-noise ratio for stationary stochastic inputs, including single and multiple reference inputs. These solutions show that when the reference input is free of signal and certain other conditions are met noise in the primary input can be essentiany eliminated without signal distortion. It is further shown that in treating periodic interference the adaptive noise canceller acts as a notch filter with narrow bandwidth, infinite null, and the capability of tracking the exact frequency of the interference; in this case the canceller behaves as a linear, time-invariant system, with the adaptive filter converging on a dynamic rather than a static solution. Experimental results are presented that illustrate the usefulness of the adaptive noise cancelling technique in a variety of practical applications. These applications include the cancelling of various forms of periodic interference in electrocardiography, the cancelling of periodic interference in speech signals, and the cancelling of broad-band interference in the side-lobes of an antenna array. In further experiments it is shown that a sine wave and Gaussian noise can be separated by using a reference input that is a delayed version of the primary input. Suggested applications include the elimination of tape hum or turntable rumble during the playback of recorded broad-band signals and the automatic detection of very-low-level periodic signals masked by broad-band noise.

/pdf/adaptive-noise-cancelling-principles-and-applications-1kc4rr7avw.pdf

Adaptive noise cancelling: Principles and applications

Photoplethysmography (PPG) is a simple and low-cost optical technique that can be used to detect blood volume changes in the microvascular bed of tissue. It is often used non-invasively to make measurements at the skin surface. The PPG waveform comprises a pulsatile ('AC') physiological waveform attributed to cardiac synchronous changes in the blood volume with each heart beat, and is superimposed on a slowly varying ('DC') baseline with various lower frequency components attributed to respiration, sympathetic nervous system activity and thermoregulation. Although the origins of the components of the PPG signal are not fully understood, it is generally accepted that they can provide valuable information about the cardiovascular system. There has been a resurgence of interest in the technique in recent years, driven by the demand for low cost, simple and portable technology for the primary care and community based clinical settings, the wide availability of low cost and small semiconductor components, and the advancement of computer-based pulse wave analysis techniques. The PPG technology has been used in a wide range of commercially available medical devices for measuring oxygen saturation, blood pressure and cardiac output, assessing autonomic function and also detecting peripheral vascular disease. The introductory sections of the topical review describe the basic principle of operation and interaction of light with tissue, early and recent history of PPG, instrumentation, measurement protocol, and pulse wave analysis. The review then focuses on the applications of PPG in clinical physiological measurements, including clinical physiological monitoring, vascular assessment and autonomic function.

https://iopscience.iop.org/article/10.1088/0967-3334/28/3/R01/pdf

Photoplethysmography and its application in clinical physiological measurement.

Physiological systems bioelectric phenomena biomechanics biomaterials biosensors biomedical signal analysis imaging medical instruments and devices biological effects of non-ionizing biotechnology tissue engineering human performance engineering physiological modelling, simulation and control clinical engineering and artificial intelligence. (Part contents).

The Biomedical Engineering Handbook

Biomedical surface science: Foundations to frontiers

Measurement Characteristics. Spatial Variables Measurement. Time and Frequency Measurement. Mechanical Variables Measurement Solid. Mechanical Variables Measurement Fluid. Mechanical Variables Measurement Thermal. Electromagnetic Variables Measurement. Optical Variables Measurement. Radiation Measurement. Chemical Variables Measurement. Biomedical Variables Measurement. Signal Processing. Displays. Control. Appendices. Index.

The Measurement, Instrumentation and Sensors Handbook

From the Publisher:
This objective, referenced collection of over 300 articles will cover every aspect of medical devices and instrumentation in four volumes, totalling about 3,000 pages. The Encyclopedia will define the discipline by bringing together the core of knowledge from all the fields encompassed by the application of engineering, physics, and computers to problems in medicine. Some of the many areas covered will include: anaesthesiology; burns; cardiology; clinical chemistry and engineering; critical care medicine; dermatology; dentistry; endocrinology; genetics; gynecology; microbiology; oncology; pharmacology; psychiatry; radiology; surgery; and urology. Cross-references and index included.

Encyclopedia of Medical Devices and Instrumentation

Normal oxygen transport (S A Clark). Motivation of pulse oximetry (D J Sebald). Blood oxygen measurement (J Farmer). Light absorbance in pulse oximetry (O Wieben). Light-emitting diodes and their control (B W J Bourgeois). Photodetectors and amplifiers (J S Schowalter). Probes (M V S Reddy). Electronic instrument control (K S Paranjape). Signal processing algorithms (S Palreddy). Calibration (J S Schowalter). Accuracy and errors (S Tungjitkusolmun). User interface for a pulse oximeter (A Lozano-Nieto). Applications of pulse oximetry (J B Ruchala). Glossary. Index.

Design of Pulse Oximeters

One of the major problems encountered in recording ECG's is the appearance of unwanted 60-Hz interference in the output. This paper examines the many possible sources of interference, and for each provides a description, an identifying test, and a remedy. Then we look at possible equipment imperfections and guidelines for amplifier design to aid in the evaluation of new developments in the field of electrocardiography. As an illustrative example, we apply the procedure for isolating the source of interference to an exposition display in which each visitor could rapidly view his own ECG.

60-Hz Interference in Electrocardiography

Motion artifacts frequently cause erroneous results in biopotential measurement. When surface electrodes and conducting paste are used, a major cause of motion artifact is change in skin potential. The most effective means of minimizing this artifact is light abrasion of the sidn with fine sandpaper. A very mild paste is then required to avoid skin irritation.

John G. Webster

Papers

The Measurement, Instrumentation and Sensors Handbook

Encyclopedia of Medical Devices and Instrumentation

Design of Pulse Oximeters

60-Hz Interference in Electrocardiography

Minimizing Electrode Motion Artifact by Skin Abrasion