Dynamics of short pressure probes

Report presents practical information for incorporating particle impact protection features and average total pressure measurement into probe design while optimizing probe transient response. Computer program calculates probe response, based on Bergh-Tijdeman equation

Sinusoidal-pressure generator for testing dynamic pressure probes

Generator can produce sinusoidal pressures at frequencies from 300 to 5000 Hz and peak-to-peak amplitudes up to 5.6 lbs/sq in. Amplitude and phase-angle measurements made at various frequencies are compared with measurements from a piezoelectric transducer mounted flush with the resonant tube wall

Similar group mean scores, but large individual variations, in patient-relevant outcomes over 2 years in meniscectomized subjects with and without radiographic knee osteoarthritis.

Background Epidemiological studies have, so far, identified factors associated with increased risk for incident or progressive OA, such as age, sex, heredity, obesity, and joint injury. There is, however, a paucity of long-term data that provide information on the nature of disease progression on either group or individual levels. Such information is needed for identification of study cohorts and planning of clinical trials. The aim of the study was, thus, to assess the variation in pain and function on group and individual level over 2 years in previously meniscectomized individuals with and without radiographic knee osteoarthritis (OA). Methods 143 individuals (16% women, mean age at first assessment 50 years [range 27–83]) were assessed twice; approximately 14 and 16 years after isolated meniscectomy, with a median interval of 2.3 years (range 2.3–3.0). Radiographic OA (as assessed at the time of second evaluation) was present in the operated knee in 40%, and an additional 19% had a single osteophyte grade 1 in one or both of the tibiofemoral compartments. Subjects completed the self-administered and disease-specific Knee injury and Osteoarthritis Outcome Score (KOOS). Results There were no significant changes in the group mean KOOS subscale scores over the 2-year period. However, a great variability over time was seen within individual subjects. Out of 143 subjects, 16% improved and 12% deteriorated in the subscale Pain, and 13% improved and 14% deteriorated in the subscale ADL ≥ 10 points (the suggested threshold for minimal perceptible clinical change). Similar results were seen for remaining subscales. Conclusion Group mean scores for this study cohort enriched in incipient and early-stage knee OA were similar over 2 years, but pain, function and quality of life changed considerably in individuals. These results may be valid also for other at risk groups with knee OA, and motivate further careful examination of the natural history of OA, as well as properties of the OA outcome instruments used. Longitudinal outcome data in OA studies need to be analyzed both on an individual and a group level

Rheumatoid arthritis as underlying cause of death in 31 countries, 1987-2011: Trend analysis of WHO mortality database

Objective To examine trends in rheumatoid arthritis (RA) as an underlying cause of death (UCD) in 31 countries across the globe during 1987-2011. Methods Data on mortality and population were collected from the World Health Organization mortality database and the United Nations. Age-standardized mortality rates (ASMR) were calculated by means of direct standardization. We applied joinpoint regression analysis for trend analysis. Between-country disparities were examined using between-country variance, and Gini coefficient. Due to low numbers of deaths, we smoothed our ASMR using a three-year moving average. The changes in number of RA deaths between 1987 and 2011 were decomposed using two counterfactual scenarios. Results The absolute number of deaths with RA registered as UCD declined from 9281 (0.12% of all-cause deaths) in 1987 to 8428 in 2011 (0.09% of all-cause deaths). The mean ASMR declined from 7.1/million person-years in 1987-89 to 3.7 in 2009-11 (48.2% reduction). Reduction of 25% or more in ASMR occurred in 21 countries while a corresponding increase was observed in 3 countries. There was a persistent reduction in RA mortality and, on average, the ASMR declined by 3.0% per year. The absolute and relative between-country disparities declined over the study period.CONCLUSION: Mortality rates attributable to RA have declined globally. However, there were substantial between-country disparities in RA mortality, though the disparities decreased over time. Population aging combined with fall in RA mortality may lead to an increase in the economic burden of disease that should be taken into consideration in policy-making. This article is protected by copyright. All rights reserved