Reliability of spectral EMG parameters of healthy back extensors during submaximum isometric fatiguing contractions and recovery

Spectral EMG parameters are being used as an objective evaluation of low back rehabilitation programs. The reliability of these spectral parameters is important in determining the validity of this evaluation tool. Two groups of eight subjects, with no history of back pain, were measured: the first group every day for one week; the second group one day per week for four weeks. During each session, subjects performed a 30-second isometric fatiguing contraction of the back extensors at 60% MVC followed by a 60-second rest and a 10-second repeat contraction. The intraclass correlation coefficient (ICC) did not demonstrate high reliability (ICC<0.6) for the rate of median power frequency (MedPF) change (Hz/s), the magnitude of the recovery (Hz) and differences between the dominant and the non-dominant sides within a subject. However, the initial MedPF (Hz) of the fatigue and repeat contractions demonstrated excellent reliability (ICC>0.8) with five or more repeated measures. The practical implication of this work is that the experimental condition must have sufficiently large changes in MedPF (signal)—at least larger than the variability inherent in the MedPF (noise)—to constitute a valid measure.     

Combustion of cotton gin residues in a lime kiln reactor

Combustion of cotton gin residues was studied in the furnace of a continuous-operation, modern lime kiln. During its first period of operation, the plant experienced some problems; corrosion of the refractory bricks, difficulty in controlling the temperature at the main burner, a hard mass of lime building up inside the kiln and around the main burner. However, in spite of the problems successful production of lime was finally achieved. Measurements show that the use of cotton gin residues as a combustible material does not create any significant changes either in the quality of the lime or in the environment.     

Mitochondrial morphogenesis: Fusion factor for fly fertility

The Drosophila Fzo protein is required for mitochondrial fusion during a key step in sperm formation. This novel, membrane-bound GTPase defines a family of proteins that may mediate mitochondrial fusion in a variety of eukaryotic cells.