Author: John Mulindi
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The Principle of Temporal Artery Thermometer
This is a non-invasive scanning thermometer for measuring core body temperature. The measurement is based on scanning the area above the temporal artery using an IR detector. The superficial temporal artery extends directly from the external carotid artery and travels in front of the ear. Anatomically, it is lying approximately 1 mm below the skin,…
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Basic Features of Enzyme Based Biosensors
Enzymes are the commonly used biological sensing element in the fabrication of various biosensors. Enzymes have unique properties and ability to accelerate chemical reactions inside biological cells. Most enzymes react only with specific substrates even though they may be contained in a complicated mixture with other substances. However, it is imperative to keep in mind,…
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Fleisch Pneumotachometer Operation & Biomedical Application
Fleisch Pneumotachometer is one of the most common types of airflow transducers. It consists of a straight short-tube with a fixed screen obstruction in the middle that produces a slight pressure drop as the air is passed through the tube. The pressure drop created across the screen is measured by a differential pressure transducer. The…
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The Function of a PET scan in Biomedical Diagnostics
The radionuclides that are employed in a PET scan as part of radiopharmaceuticals work best when used for imaging certain physiological properties. Combined with a CT scan or an MRI, a PET scan is good for locating things such as tumours. As a matter of fact, a PET scan can light up for the brain,…
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Key Features of EMG Amplifiers
The amplifiers used for clinical EMG recording must meet same strict specifications for low-leakage currents as do ECG, EEG, and any other amplifiers used to measure human body potentials. EMG amplifier gains are typically x1000 and their bandwidths reflect the transient nature of the single motor unit (SMU) action potentials. An EMG amplifier is generally…
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Cardioverter Operation & Biomedical Application
When an operator applies an electric shock of the magnitude of that from a dc defibrillator to the patient’s chest during the T wave of the ECG, there is a strong risk of producing ventricular fibrillation in the patient. Because the most frequent use of defibrillation is to terminate ventricular fibrillation, this problem does not…
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5 Established Isolation Architectures for Medical Isolation Amplifiers
Medical isolation amplifiers provide an ultra-low conductive pathway between the input (patient) terminals and the output terminals and ground. This pathway provides what is called ohmic or galvanic isolation for a patient. In medical applications, this isolation is required for reasons of patient safety. The dc resistance between input and output terminals is typically on…
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The Origin of EMG Biosignals
Introduction A key bioelectric signal that has diagnostic significance for various neuromuscular diseases is the electromyogram (EMG), which can be recorded from the skin surface with electrodes identical to those used for electrocardiography, although in some cases, the electrodes have smaller areas than those used for ECG ( <1 mm2). To record from single motor…
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Biosignals Data Acquisition
Biological signals are often very minute and typically contain unwanted interference or noise. Such interference has the detrimental effect of obscuring relevant information that may be available in the measured signal. Noise can be extraneous in nature arising from sources outside the body, such as thermal noise in sensors or 60-cycle noise in the electronic…
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Comparison of Imaging Modes – Ultrasound, CT & MRI
How the three imaging modalities compare? We examine each of the three diagnostic imaging methods as discussed in the following sections: Ultrasound Imaging Unlike other imaging modalities, ultrasound resolution and penetration depends on the center frequency and type of frequency selected. The resolution is spatially variant and depends on both the size of the active…