The natural history of chronic obstructive pulmonary disease

Chronic obstructive pulmonary disease (COPD) is a leading cause of morbidity and mortality in the USA, and it remains one of the few diseases that continues to increase its numbers. The development and progression of COPD can vary dramatically between individuals. A low level of lung function remains the cornerstone of COPD diagnosis and is a key predictor of prognosis. Lung function, however, is not the only factor in determining morbidity and mortality related to COPD, with factors such as body mass index, exercise capability and comorbid disease being important predictors of poor outcomes. Exacerbations of COPD are additional important indicators of both quality of life and outcomes in COPD patients. Definitions of exacerbations can vary, ranging from an increase in symptoms to COPD-related hospitalisations and death. COPD exacerbations are more common in patients with lower levels of lung function and may lead to more rapid declines in lung function. Better understanding of the natural history of COPD may lead to better definitions of specific COPD phenotypes, better interventions and improved outcomes

Signal conditioning electronics for UHF partial discharge detection and location system.

Partial Discharge (PD) occurs in damaged high-voltage insulation. PD results in UHF electromagnetic radiation which can be used to detect and locate insulation faults in HV power systems equipment such as transmission lines and transformers thereby providing early indication of equipment failure [1 - 5]. The majority of the power in the PD radiation is contained in the band 50 MHz to 800 MHz. A wireless sensor network (WSN) is being designed and implemented to receive this PD radiation to provide a non-invasive method of locating and monitoring PD. Each WSN node is required to operate for as long as possible (≥1 year) without the need to change the energy source and to be sufficiently cheap to make a dense sensor network viable. Low cost, low power, circuitry for each node has therefore been developed. It is impractical to consider sampling radiated PD signals directly due to their large bandwidth leading to large data storage and/or data transmission requirements. The system being developed reduces signal bandwidth, and therefore the sampling rate and volume of data to be processed, using signal conditioning electronics (SCE) based on a transistor-reset integrator (TRI)