Analysis of parameters of haemostasis in pre-eclamptic, normotensive pregnant and non-pregnant women.

Pregnancy is characterized by a state of heightened coagulation, which is exacerbated in pathological conditions such as pre-eclampsia (PET). PET is further associated with abnormal maternal inflammation and increased circulating microparticles (MP); however, a mechanistic link between these pathological features has never been established. It is proposed in this thesis that abnormal maternal inflammation is causally linked to pro-coagulant trophoblast MP shedding via a mechanism mediated by the pro-inflammatory cytokine tumour necrosis factor alpha (TNF), thereby contributing to maternal coagulopathies associated with PET. Using thromboelastography (TEG) and standard laboratory tests, haemostatic function was evaluated in PET and normotensive subjects at delivery and post-partum. Furthermore, the effects of the menstrual cycle and oral contraceptive (OC) use on haemostatic function were assessed in non-pregnant subjects in order to understand their influence on post-partum haemostasis. Plasma TNF and pro-coagulant MP levels were evaluated in the pregnant subjects. Using chorionic villi explants from human term placentas, MPs were quantified after TNF administration. The pro-coagulant potential of placental MPs was evaluated by TEG by spiking whole-blood with medium containing MPs from chorionic villi. TEG identified increased whole-blood coagulability in PET subjects at delivery, demonstrating its increased sensitivity over standard laboratory tests at identifying haemostatic alterations associated with PET. Haemostatic alterations were normalized by six weeks post-partum. TEG also identified cyclic haemostatic variations associated with OC use. Chorionic villi treated with TNF (1 ng/ml) shed significantly more MPs than untreated placentas. MPs from chorionic villi increased the coagulability of whole-blood. Together, results provide evidence supporting the concept that abnormal maternal inflammation is causally linked to the development of maternal coagulopathies in pregnancy complications. Moreover, TEG may be superior to standard laboratory tests in evaluating haemostasis in pregnant and non-pregnant subjects.

Towards Extracting Absolute Roughness From Underground Mine Drift Profile Data

The purpose of this paper is to demonstrate a technique to utilize underground mine drift profile data for estimating absolute roughness of an underground mine drift in order to implement the Darcy-Weisbach equation for mine ventilation calculations. This technique could provide mine ventilation engineers with more accurate information upon which they might base their ventilation systems designs. This paper presents preliminary work suggesting that it is possible to estimate the absolute roughness of drift-like tunnels by analyzing profile data (e.g., collected using a scanning laser rangefinder). The absolute roughness is then used to estimate the friction factor employed in the Darcy-Weisbach equation. The presented technique is based on an analysis of the spectral characteristics of profile ranges. Simulations based on real mine data are provided to illustrate the potential viability of this method. It is shown that mining drift roughness profiles appear similar to Gaussian profiles