The purpose of the study was to examine psychological and methodological factors which would predict the white coat effect (WCE). The WCE is defined as the difference (mm Hg) between ambulatory and office measured blood pressure (BP). Sixty three community volunteers participated in this study. Participants were divided into 3 Response style groups: (1) Office responders had ambulatory BP values which were lower than office BP, (2) Non responders showed a minimal difference between office and ambulatory BP, and (3) Home responders had significantly higher ambulatory BP compared to office BP. Participants were asked to have a series of BP readings taken by a physician, nurse and by themselves and participate in 24 hour ambulatory monitoring. State and trait self-report psychological measures were completed. Self measured BP was the most representative of ambulatory BP for the sample as a whole, and in particular for the Home responders. State anxiety, previously dismissed as mediating factor in the expression of the white coat effect, proved to discriminate between the groups. Office responders had significantly higher levels of state anxiety, directly related to BP measurements, compared to Home and Non responders. Habituation to the experience of having BP measured by a physician, and habituation of the anxiety prior to the BP measurement, was different among the three groups. Trait psychological variables did not distinguish group membership. Self measured systolic BP, state anxiety prior to self measured BP, habituation to physician measured BP and the anxiety preceding it, were entered as predictors variables in a discriminant function analyses. These variables were able to correctly classify group membership for 63% of the sample. / Arts, Faculty of / Psychology, Department of / Graduate

Hypertension guidelines recommend out of office blood pressure (BP) measurement especially 24- hour ambulatory measurement (ABPM), to diagnose and manage hypertension but this is not routinely performed in kidney transplant units. This study was to determine if 24-hour ABPM, compared with office BP in kidney transplant recipients, would be more informative regarding BP management, and if pulse wave analysis (PWA) would assist in risk stratification. This study included patients older than 18 years, with working graft kidney for >12 months, and without problems affecting BP measurement and interpretation. After performing office BP measurements, a 24-hour ABPM with additional capability of calculating pulse wave velocity (PWV),augmentation index and central BP was undertaken. Patients were assessed for controlled hypertension, uncontrolled hypertension, masked hypertension, nocturnal hypertension, white coat hypertension, and dipping BP status. Data were analysed using standard statistical tests. Of 30 patients, 15 were Black Africans and 15 were of Mixed Ancestry with a mean age of 48.9 years. Seventeen patients were males and 36.7% had controlled hypertension, 30% uncontrolled hypertension, 6.7% white coat hypertension and 33.3% masked hypertension, of whom 70% had isolated nocturnal hypertension. 70% had a non-dipping, 26.7% a reverse dipping and only 3.3% had a normal dipping BP pattern. The mean difference between brachia! systolic BP and central systolic BP was 10.4 mm Hg, whereas PWV and augmentation index were similar to healthy populations. CONCLUSION: In kidney transplant recipients, 24-hour ABPM was superior to office BP in defining hypertensive status that qualified for modification of therapy but PWA did not contribute to risk assessment.

No description available.

Thesis: M.S., Massachusetts Institute of Technology, Department of Mechanical Engineering, 1980 / Bibliography: leaves 216-232. / by Francis Joseph Halcomb, III. / M.S. / M.S. Massachusetts Institute of Technology, Department of Mechanical Engineering

In geotechnical engineering, it has proven difficult to obtain reliable soil parameters for stiff clays. Laboratory testing results are often scattering due to the fissures and slickensides in these soils. Alternatively, in situ techniques offer a means to test the soils in place. This study focuses on in situ testing in Miocene stiff clays using an advanced nine strain arm self-boring pressuremeter (SBPM). This device was used to test the soils in both a self-boring and a simpler, non-boring mode (pre-bored or PBPM tests). The Miocene stiff clay was unique in that was sensitive and lacked of fissures and slickensides. The pressuremeter results could be compared to a range of other tests previously performed at the site. It is concluded that the SBPM provides accurate values of modulus and strength. Minor soil disturbance was found to have little effect when it could be anticipated. The simpler PBPM tests were not successful because of disturbance caused by borehole preparation. / Ph. D.

A new pressure-measurement technique which employs the tools of molecular spectroscopy has recently received considerable attention in the fluid mechanics community. Measurements are made via oxygen-sensitive molecules attached to the surface of interest as a coating, or paint. The pressure-sensitive-paint (PSP) technique is now commonly used in stationary wind-tunnel tests; this thesis presents the extension of the technique to advanced turbomachinery applications. New pressure- and temperature-sensitive paints (TSPs) have been developed for application to a state-of-the-art transonic compressor where pressures up to 2 atm and surface temperatures up to 140° C are expected for the first-stage rotor. PSP and TSP data has been acquired from the suction surface of the first-stage rotor of a transonic compressor operating at its peak-efficiency condition. The shock structure is clearly visible in the pressure image, and visual comparison to the corresponding computational fluid dynamics (CFD) prediction shows qualitative agreement to the PSP data. / Master of Science

No description available.

Data were collected from the initial symptom-limited maximal exercise tests of 161 patients without. diagnosed coronary heart disease (CHD). Subjects were grouped according to their systolic (SBP) and diastolic (DBP) blood pressure changes between the final two stages of exercise. / Master of Science

Several methods have been developed to capture shock waves in turbo machinery flows, such as Moore's pressure correction procedure and Denton's time marching procedure. The time marching procedure is traditionally used for transonic flow calculations, whereas the pressure correction method is better suited for incompressible and subsonic flows. However, the focus of this research is on the Moore pressure correction flow code, the Moore Elliptical Flow Program (MEFP) , to calculate shock waves in transonic compressor fans. A new pressure interpolation method, the 2M formula, is developed to improve the shock capturing capabilities of the MEFP flow code. The 2M formula is a two Mach number dependent formula, with Mach numbers Mi and M i + 1. The previously used pressure interpolation method, the M&M formula, is a one Mach number dependent formula, using the maximum of Mi and Mi + 1 . In the development of the 2M formula, J.G. Moore's stability criterion is applied to the pressure correction equation such that the center point coefficient is greater than the sum of the other positive coefficients. / Master of Science

A microprocessor based air pressure controller is discussed. The particular implementation was designed around an existing pressure measurement, and display unit. The unit is controlled by a 6809 microprocessor. It is shown that due to the many functions that the unit must perform and control, a microprocessor based system is a good choice. The controller is economical since it uses standard chips, yet it is very accurate since it uses state of the art pressure transducers. Experimental results and the user friendly interface will also be discussed. A commented listing of the controller software, and the circuit diagrams are appended. / Master of Science