Biomedical subjects

M Edström

Publications and source records attributed to M Edström.

4 recordsLinked to original sources

PubMed2005

Co-digestion of energy crops and the source-sorted organic fraction of municipal solid waste.

The biological and technical performance during co-digestion of energy crops and the source-sorted organic fraction of municipal solid waste has been investigated at laboratory and pilot scale. A 50:50 (TS-based) mixture of energy crops and organic waste reached a loading rate of 6.0 gVS L(-1)d(-1) with a methane yield of 0.33-0.38 LgVS(-1), while a 80:20 mixture showed elevated levels of volatile fatty acids at 5.5 gVS L(-1)d(-1) The better performance of the 50:50 mixture can partly be explained by a better nutritional composition. Mincing the ley crop reduced viscosity and reduced problems with fibre floating and scum-blanket formation. The electricity consumed for mincing and stirring at a full-scale plant corresponds to ca 3% of the energy produced. Calculations of the costs for full-scale plants indicate that the price of the upgraded biogas has to be at least 0.078 Euro/kWh in order to balance the costs.

Agriculture↗

PubMed1997

Why exercise?: a preliminary investigation of an exercise motivation index among individuals with rheumatic conditions and healthy individuals.

The study was undertaken to investigate the test-retest stability and the criterion-related validity of a modified Swedish version of an exercise motivation index (EMI), and its use with individuals with rheumatic conditions, and with healthy individuals who exercised regularly. The EMI consists of 23 statements divided into three sub-scores for physical, psychological and social motivation. Ninety-five individuals with rheumatic conditions (mean age 60 years, mean symptom duration 15 years, 79% female) and 131 healthy individuals (mean age 52 years, 76% female), all attending exercise classes at least once a week, filled out the EMI. Sub-samples also filled out three visual analogue scales designed to measure physical, psychological and social exercise motivation, and filled out the EMI a second time one week later. The results indicated that psychological and physical exercise motivation was equally important in both samples. Social motivation was less important in both samples, but more pronounced in the rheumatic sample and among older individuals. In the rheumatic sample, physical motivation was more important among women and psychological motivation was more important among younger individuals. Test-retest stability for the EMI was satisfactory in both samples, while criterion-related validity was poor. The results of our preliminary investigation of the EMI suggest that the survey of physical, psychological and social motivation for exercise seems meaningful. Further work on the validity of the EMI is needed.

Case-Control Studies↗

PubMed1993

Fatigue in the shoulder muscles during static work at two different torque levels.

The present study aimed to investigate whether and when a shift in the mean power frequency (MPF) of the electromyogram (EMG) occurs at low torque levels during a maximum endurance test of three shoulder flexors. Twelve clinically healthy women performed two endurance tests of the shoulder flexors (at 50% MVC--the high torque level, and at approximately 18% MVC--the low torque level) until maximum exhaustion. Surface EMG were obtained and MPF and signal amplitude (RMS) were computed for the trapezius descendens, the anterior part of the deltoid and the infraspinatus. The subjects also rated the perception of fatigue in the shoulder muscles throughout the two tests using a 10-graded scale. A significantly higher degree of perceived fatigue was found at the low rather than at the high torque level. In contrast significantly lower MPF were found at the end of the endurance times in the three muscles at the high torque level when compared to the low torque level. At the low torque level MPF of the trapezius was constant throughout the test. In the deltoid the most prominent decrease occurred during the initial 30-40% of the endurance time at the low torque level. It is suggested that the MPF shift mainly reflects peripheral fatigue of the type-2 fibres. The results of the present study question the use of the MPF shift to monitor peripheral fatigue in the fibres active (mainly type-1) at low torque levels.

Adult↗

PubMed1988

Surface EMG recordings during maximum static shoulder forward flexion in different positions.

This study investigated how position in the range of motion influences the power spectral density function during static shoulder forward flexion. 23 healthy females (20-30 years) volunteered as subjects. They performed maximum static shoulder forward flexions in three positions: 45, 65 and 90 degrees of shoulder flexion. An isokinetic dynamometer was used and the subjects were seated in a specially constructed chair to enable adequate fixation. The elbow was extended and the hand pronated. Electromyographic (EMG) signals (using surface electrodes) were obtained from the descending part of the right trapezius, the anterior portion of the right deltoid, the right infraspinatus and the common belly of the right biceps brachii. The four EMG-signals and the torque and shoulder angle were analyzed by computer. For each 256 ms, mean power frequency, root mean square value and mean torque were calculated. At each of the three positions four 256 ms periods were analyzed and the data are presented as their means. In the trapezius and the biceps brachii the mean power frequency did not change between the three positions. Deltoid and infraspinatus had significantly higher mean power frequencies at 90 degrees than at 45 degrees of flexion. Different factors behind the change in mean power frequency are discussed. The need to standardize the range of motion when studying dynamic fatiguing contractions is emphasised.

Adult↗