Evaluation of the Canadian Coordinating Office for Health Technology Assessment

The Canadian Coordinating Office for Health Technology Assessment (CCOHTA) was recently evaluated. We summarize the evaluation process, report, and 17 recommendations for enhancing CCOHTA's effectiveness. This paper may be useful for evaluators of agencies for technology assessment.     

Double-evoked otoacoustic emissions. II. Intermittent noise rejection, calibration and ear-canal measurements

Measurements of double-click-evoked otoacoustics emissions (2CEOAEs) and double-chirp distortion products (2ChDPs) are reported for normal-hearing adults based upon theory presented in an earlier report [Keefe, J. Acoust, Soc. Am. 103, 3489-3498 (1998)]. The nonlinear acoustic response of a probe assembly used in ear-canal measurements in tested in a calibration cavity to compare the double-evoked (2E) technique with existing OAE techniques. The 2E technique reduces the peak distortion by approximately 30 dB relative to existing click-evoked techniques. The 2E subtraction of click responses is partially analogous to current techniques in that the linear response is eliminated, but differs in that high-frequency measurements are improved by eliminating time gating of the cochlear response, and low-frequency measurements are improved by reducing probe distortion, especially when two acoustic sources are used. Because time gating is eliminated, it is straightforward to measure the onset of a click-evoked OAE. The nonlinear coherence function is used to measure the nonlinear distortion signal-to-noise ratio (DNR) for the 2ChDPs and 2CEOAEs. The DNR is typically 20-30 dB. An intermittent noise rejection technique is implemented in real time that compares a currently acquired ear-canal response with a stored response. Dissimilar responses indicate the presence of intermittent noise, and the noise-contaminated responses are thereby discarded before ensemble averaging.     

Modification of the NADH of the isoniazid target (InhA) from Mycobacterium tuberculosis

The preferred antitubercular drug isoniazid specifically targets a long-chain enoyl-acyl carrier protein reductase (InhA), an enzyme essential for mycolic acid biosynthesis in Mycobacterium tuberculosis. Despite the widespread use of this drug for more than 40 years, its precise mode of action has remained obscure. Data from x-ray crystallography and mass spectrometry reveal that the mechanism of isoniazid action against InhA is covalent attachment of the activated form of the drug to the nicotinamide ring of nicotinamide adenine dinucleotide bound within the active site of InhA.     

Fault trees revisited

Embedded in a fault tree is a vast amount of information. In this paper methods to extract this information are reviewed.