Validation of the severity index by cardiac catheterization and Doppler echocardiography in patients with aortic sclerosis and stenosis

The severity index is a new echocardiographic measure that is thought to be an accurate indicator of aortic leaflet pathology in patients with AS. However, it has not been validated against cardiac catheterization or Doppler echocardiographic measures of AS severity nor has it been applied to patients with aortic sclerosis. The purposes of this study were to compare the severity index to invasive hemodynamics and Doppler echocardiography across the spectrum of calcific aortic valve disease, including aortic sclerosis and AS. 48 patients with aortic sclerosis and AS undergoing echocardiography and cardiac catheterization comprised the study population. The aortic valve leaflets were assessed for mobility (scale 1 to 6) and calcification (scale 1 to 4) and the severity index was calculated as the sum of the mobility and calcification scores according to the methods of Bahler et al. The severity index increased with increasing severity of aortic valve disease; the severity indices for patients with aortic sclerosis, mild to moderate AS and severe AS were 3.38 ± 1.06, 6.45 ± 2.16 and 8.38 ± 1.41, respectively. The aortic jet velocity by echocardiography and the square root of the maximum aortic valve gradient by cardiac catheterization correlated well with the severity index (r = 0.84, p < 0.0001; r = 0.84, p < 0.0001, respectively). These results confirm that the severity index correlates with hemodynamic severity of aortic valve disease and may prove to be a useful measure in patients with aortic sclerosis and AS

Flow physics during the drying of a thin polymer solution film near the contact line

The drying process of a thin polymer solution film has been studied inside a micro-liter cavity near the contact line. Confocal microscopy along with particle image velocimetry and laser induced fluorescence are used for the real time measurement of velocity and concentration fields during the drying process. In addition to the capillary flow and the Marangoni flow, the velocity field also reveals the possible existence of a single vortex and multiple vortices inside the creeping flow induced by evaporation. These vortices appear soon after the beginning of the evaporation process, their size shrinks over time, and they disappear before the end of the evaporation process. This thesis includes a study of the effect of rheological and geometrical parameters on the presence, size and endurance of these vortices. Significant concentration heterogeneity is observed across the film during the drying process, in particular near the contact line. The concentration at the solution-air interface is higher compared to the bulk, and it increases towards the contact line and also over time. A skin layer starts forming as soon as the surface concentration reaches the glass transition concentration after which the evaporation rate starts decreasing. The drying film undergoes a similar concentration evolution during the evaporation process, regardless of the cavity depth and the initial polymer concentration; although, minor differences can be recognized that are associated with the flow recirculations that delay the concentration increase inside the vortex. Finally, a theory is developed based on experimental data which explains the existence and behavior of viscous vortices near the bottom wall of the cavity. The competition between the capillary flow and the Marangoni flow results in flow separation on the bottom wall which leads to such vortices. This study provides better understanding of the drying process of thin polymer solution films near the contact line. Furthermore, viscous flow separation adds to the current understanding of flow physics during the drying process, in addition to the well-known evaporation induced capillary transport and the Marangoni effect.Applied Science, Faculty ofMechanical Engineering, Department ofGraduat

Glazing in residential high rise buildings energy saving vs. the optimum day lighting

Disclaimer: “UBC SEEDS provides students with the opportunity to share the findings of their studies, as well as their opinions, conclusions and recommendations with the UBC community. The reader should bear in mind that this is a student project/report and is not an official document of UBC. Furthermore readers should bear in mind that these reports may not reflect the current status of activities at UBC. We urge you to contact the research persons mentioned in a report or the SEEDS Coordinator about the current status of the subject matter of a project/report.”Applied Science, Faculty ofUnreviewedGraduat

Hyperglycemia: A Predictor of Death in Severe Head Injury Patients

Objectives Management of hyperglycemia during an acute sickness in adults is accompanied by improved outcomes. We have designed a prospective study with meticulous attention to exclude all diabetes patients by checking hemoglobin A1c (HbA1c or glycated hemoglobin) to avoid the ill-effects of hyperglycemia in patients with traumatic head injury admitted to the intensive care unit (ICU). Methods This prospective study included adults with traumatic primary brain injury with a Glasgow coma score of ≥8 necessitating mechanical ventilation treated in the period 2012–2015. After screening 311 patients, 220 were included in the study. Both blood glucose and HbA1c levels of all the patients at admission, as well as blood glucose level after 72 hours, were obtained from the records. The patients were later grouped based on their admission blood glucose levels (<200 mg/dL or ≤200 mg/dL). Injury severity score (ISS) was documented for every patient. As a final point, the outcomes were determined based on the hospital length of stay (HLS) and ICU length of stay (ILS), plusmortality rates. Results About 39% ( n = 85) of patients were admitted with hyperglycemia during the study period. The mortality rate in patients with glucose ≤200 mg/dL was 65.8% ( N = 56), against 23.7% ( N = 32) in the group with glucose <200 mg/dL, with mortality rising as the blood glucose level increased ( P = 0.014). Conclusions We conclude that admission hyperglycemia is related with increased mortality rate in head injury patients, and comprehensive treatment of hyperglycemia can improve the outcome of severe head injury patients

Validation of the severity index by cardiac catheterization and Doppler echocardiography in patients with aortic sclerosis and stenosis.

The severity index is a new echocardiographic measure that is thought to be an accurate indicator of aortic leaflet pathology in patients with AS. However, it has not been validated against cardiac catheterization or Doppler echocardiographic measures of AS severity nor has it been applied to patients with aortic sclerosis. The purposes of this study were to compare the severity index to invasive hemodynamics and Doppler echocardiography across the spectrum of calcific aortic valve disease, including aortic sclerosis and AS. 48 patients with aortic sclerosis and AS undergoing echocardiography and cardiac catheterization comprised the study population. The aortic valve leaflets were assessed for mobility (scale 1 to 6) and calcification (scale 1 to 4) and the severity index was calculated as the sum of the mobility and calcification scores according to the methods of Bahler et al. The severity index increased with increasing severity of aortic valve disease; the severity indices for patients with aortic sclerosis, mild to moderate AS and severe AS were 3.38 +/- 1.06, 6.45 +/- 2.16 and 8.38 +/- 1.41, respectively. The aortic jet velocity by echocardiography and the square root of the maximum aortic valve gradient by cardiac catheterization correlated well with the severity index (r = 0.84, p &lt; 0.0001; r = 0.84, p &lt; 0.0001, respectively). These results confirm that the severity index correlates with hemodynamic severity of aortic valve disease and may prove to be a useful measure in patients with aortic sclerosis and AS