Electromyography
Paul Grimshaw, Michael Cole, Adrian Burden, Neil Fowler in Instant Notes in Sport and Exercise Biomechanics, 2019
Most commercially available electromyographical systems can be classified as either hard-wired, telemetry or data logger systems (Figure G5.2). A data logger or telemetry system is necessary if data is to be collected away from the main recording apparatus; however, data loggers typically do not allow online viewing of EMGs as they are being recorded and telemetry systems can be prone to ambient noise. Hard-wired systems do not suffer from these limitations, but obviously preclude data collection outside of the vicinity of the recording apparatus. The fidelity of the recorded EMG is dependent on the characteristics of the (differential) amplifier that is connected to the electrodes. These are listed below with recommended minimum specifications: Input impedance (>100 MΩ)Common mode rejection ratio (CMRR) (>80 dB [10,000])Input referred noise (<1–2 µV rms)Bandwidth (20–500 Hz)Gain (variable between 100 and 10,000)
Medical Evaluation of Functional GI Disorders
Kevin W. Olden in Handbook of Functional Gastrointestinal Disorders, 2020
Prolonged (usually 24-hour) esophageal pH monitoring is performed by placing a small probe transnasally so that its tip is located 5 cm above the lower esophageal sphincter. A data-logger records pH and patient symptoms such as heartburn, chest pain, and cough and major events such as meal ingestion and lying down (Figure 5). In general, most centers diagnose significant reflux when the pH is below 4 for 5.8% of the duration of the study (18). The pattern of reflux relative to major events may also help identify the nature of “reflux” symptoms. For example, repetitive short-duration drops in the esophageal pH postprandially without reportings of heartburn and the lack of occurrence of reflux in the supine position may alert the physician to the possibility of rumination syndrome. On the other hand, prolonged periods of low intraesophageal pH with slow resumption of the normal neutral or slightly alkaline pH in the esophagus suggest that esophageal clearance mechanisms are impaired. These observations complement the manometric demonstration of the weakness of antireflux functions and may be useful in practice because they may permit selection of patients for prokinetic as well as antiacid secretory drugs.
Neutron Dosimetry
Gad Shani in Radiation Dosimetry, 2017
A rem counter with a response tailored to match the shape of H*(10)/Φ as defined by ICRU and ICRP has been developed by Burgkhard et al. [54] The rem counter LB 6411 consists of a polyethylene moderator sphere with a diameter of 25 cm, a central cylindrical 3He proportional counter, and internal Cd absorbers and perforations. Theinstrument has an integrated high-voltage supply and signal processing and is connected to a microprocessor-controlled portable data logger. Counter features are summarized in Table 10.11.
Evaluation of vibrant muscles over the shoulder region among workers of the hand screen printing industry
Published in International Journal of Occupational Safety and Ergonomics, 2018
Shankar Subramaniam, Naveenkumar Raju, Karthick Jeganathan, Mohankumar Periyasamy
EMG signals were recorded using the DataLOG SEMG system (Biometrics, UK) [27,28], which has eight independent programmable channels with about 20-kHz sampling rate per channel and an automatic anti-alias digital filter operating at approximately –3 dB at 0.45 × sampling rate and a maximum attenuation of –13 dB above 0.8 × sampling rate. The DataLOG system was interfaced to a laptop to control the system remotely. The SEMG sensor (SX230; Biometrics, UK) used for the study is an active probe with amplifier input impedance >10,000,000 MΩ. Because of the aforementioned input impedance, only a small amount of skin preparation is required and no conducting gels are necessary to acquire the EMG signals. This EMG sensor could just be placed on the muscle using die-cut, medical-grade, double-sided adhesive tape. A twin-axial goniometer (SG110; Biometrics, UK) was used to measure the angular movement of the trunk. It has an accuracy of ±2° measured over a range of ±90°; the repeatability of the goniometer is 1° measured over a range of 90° and the life of the goniometer is 600,000 cycles.
Upper trapezius fatigue in carpet weaving: the impact of a repetitive task cycle
Published in International Journal of Occupational Safety and Ergonomics, 2018
Neda Mahdavi, Majid Motamedzade, Ali Ashraf Jamshidi, Ebrahim Darvishi, Abbas Moghimbeygi, Rashid Heidari Moghadam
The recorded data were digitized, using DATALOG software and were processed by a custom program (MathWorks version 7.8.0.347 [R2009a]). The EMG sampling frequency was 1000 Hz. In addition, the 10–450 Hz band pass, zero-lag Butterworth, 6th-order filter was applied. The notch filter was applied in order to remove the 50 Hz signals from EMG recordings. Normalized rms (N–rms) and MPF were utilized as amplitude and frequency spectrum characteristics of the EMG, respectively. To calculate rms, the EMG signals were rectified and the low-pass signals were filtered (2 Hz). The rms value obtained in the standard isometric test contraction was used as a reference posture for normalizing the rms. After performing a fast Fourier transformation (FFT) technique (sliding window size: 100 samples; overlapped window size: 50 samples), the MPF was calculated. The MPF and rms were calculated from the last 10 s of 1-min intervals (80 min).
Circadian rhythmicity of body temperature and metabolism
Published in Temperature, 2020
An alternative to telemetry, especially for field studies, is the data logger. Data loggers are devices that can record and store data. The advantage over telemetry is that the experimental subjects can move freely over large distances without causing a loss of signal. A disadvantage is that the experimenter cannot access the data until the logger is retrieved. Manufacturers of data loggers include DataTaker Ltd. (Rowville, Australia), Onset Computer Corp. (Bourne, Massachusetts), and Pico Technology Ltd. (St. Neots, United Kingdom). A very convenient data logger is the iButton temperature logger (Maxim Integrated Products, San Jose, California). These miniature loggers (16-mm diameter) can be surgically implanted like radio transmitters. Like larger loggers, iButtons have the advantage of not requiring a separate receiver and the disadvantage of not allowing on-line access to the data. Memory limitations make them unsuitable for long studies with high temporal resolution. Available at a higher price but having the ability to record data for much longer are the miniature data loggers marketed by SubCue Dataloggers (Calgary, Canada) and Star-Oddi Ltd. (Gardabaer, Iceland).
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