Thesis (M.S.)--West Virginia University, 2004. / Title from document title page. Document formatted into pages; contains xi, 110 p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 87-93).

Background Musculoskeletal problems and falls are major contributors to disabilities, both globally and in East Asia and the Pacific. Osteoporosis and falls are common in the elderly. Their impact lies in the fragility fractures that result. Of these, hip fracture is the most costly, in terms of mortality, morbidity, and the medical and social care costs incurred. With an ageing population, the number of hip fractures is set to rise. Having a prediction model for outcomes will help risk stratification of patients, and aid planning of clinical care, rehabilitation and discharge. The objective of this study is to validate the Nottingham Hip Fracture Score for mortality prediction in Hong Kong. Methods This is a retrospective study of 2209 consecutive adult patients admitted to Caritas Medical Centre from 1st January 2007 to 31st December 2012. Data was collected from the Clinical Management System, a local rehabilitation unit database, and the Hong Kong Death Registry. Variables included to predict mortality were age, sex, place of residence, presence of ≤2 comorbidities, presence of cancer, and haemoglobin level on admission. Binary logistic regression was performed. A cognitive function test score is needed for full validation of the Nottingham Hip Fracture Score. This score was only available for patients admitted to the rehabilitation unit. A sensitivity analysis was therefore done. Results Presence of cancer [odds ratio 3.67 (2.26, 5.95)], male sex [odds ratio 2.32 (1.83, 2.93)], presence ≥2 comorbidities [odds ratio 1.38 (1.09, 1.74)] and age [odds ratio 1.05 (1.03, 1.06)] were associated with 1-year mortality. Low haemoglobin level on admission was found to be a poor prognostic factor in other studies, but appeared to be protective in ours [odds ratio 0.74 (0.70, 0.79)]. Admission from old age home was not statistically significant. Sensitivity analysis assuming both best and worst case scenarios for cognitive function test scores found the Nottingham Hip Fracture Score to be a poor prediction model in Hong Kong. Conclusions The Nottingham Hip Fracture Score was a poor prediction model in Hong Kong, because of the low hip fracture mortality rates in Hong Kong. To be locally useful, the score need to be re-calibrated. To reduce the burden of disability from hip fracture, prevention is important, as is helping patients to recover from their injury. Better understanding of variations in length of stay and discharge destinations between hospitals in Hong Kong may provide some insights into areas for improvement. / published_or_final_version / Public Health / Master / Master of Public Health

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The literature on bone growth, fracture healing, fracture treatment and the effects of forces and movements on these is reviewed. Some methods of assessing the progress of fracture union are considered. The conclusion from this is that a fracture movement transducer is needed for use on an external fracture fixator, and the design criteria are outlined. The possible types of transducers are considered and a system of light falling on lateral effect photodetectors was used. The linearizing algorithms applicable to the employed detectors are discussed and tested. The electronic circuits were designed and revised, initially to produce a reasonable power consumption, and then to give a system with reduced noise levels and improved linearity. Isolation amplifiers were required to prevent leakage currents reaching the patient from the mains powered computer. The algorithms relating the movements of the transducer to the movements at the fracture site were derived, including the use of elasticity theory to calculate the bending of the fixator pins. The engineering descriptions of the patient tests and the methods of calculating the fracture stiffness are considered. The transducer was calibrated, and consideration was given to the effect of the fixator pins loosening in the bone. Seven patients, all with tibial fractures, six injured in road traffic accidents and one footballing injury, were tested and their clinical histories were reviewed. Comparison was made between the results from the displacement transducer and a strain gauge transducer, related to the clinical history. It is concluded that this transducer, although useful, has more relevance as a research than as a clinical tool, but that further tests would lead to increased further understanding of fracture healing.

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Naturally fractured reservoirs represent significant portion of the world's oil and gas reserves. In most of the reservoirs, fractures are important contributors to fluid flow. Thus, modeling and simulation of discrete fracture network is essential to assess responses of the reservoirs under stimulation pressure, develop the best hydraulic fracture treatments, carry out feasibility studies, design optimum production methods and improve reservoir potentials. It is also a very complicated process. Natural fractures are by nature highly heterogeneous with different size, orientation and spatial distribution. The complexity is further raised, taking into account the role of matrix, the flow interaction between matrix and fractures, the effect of production-induced stress on fluid flow. Previous works fail to balance sufficient geological complexity and excessive needs of high computational resources. This thesis presents an innovative procedure to simulate stress-dependent fluid flow through discrete fracture network. Three numerical models (tensor, flow and deformation) are developed and coupled iteratively for this purpose. - A tensor model calculates grid based permeability tensor from discrete fracture network model, which includes individual fracture properties such as spatial distribution, length, location and orientation. The tensor model accounts for fluid flow from the matrix to matrix and matrix to fracture. It also includes flow through connected and disconnected fractures. - An unsteady state simulation model investigates fluid flow through the fracture system and gives pressure profile, velocity profile as output. - A dual continuum deformation model studies the reservoir rock deformation and its effects on fluid flow. The geo-mechanic solution is decomposed into matrix and fracture parts that allow calculation of dynamic porosity and permeability separately. The proposed work procedure has been validated to match nicely with analytical results. Furthermore, several case study scenarios are carried out to illustrate how it could help evaluate different aspects of reservoir performance including fracture connectivity, rock deformation, well injectivity and productivity, recovery and even distribution of fluid inside reservoir as a result of rock deformation. The case studies have proven the method to be very efficient in terms computational resources. It also eliminates most of the limitations in the previous models such as handling fracture connectivity, permeability anisotropy and change in effective stress.

Diss. (sammanfattning) Stockholm : Karol. inst., 2001. / Härtill 5 uppsatser.

Diss. (sammanfattning) Uppsala : Univ., 2001. / Härtill 5 uppsatser.

Diss. (sammanfattning) Stockholm : Karol. inst. / Härtill 6 uppsatser.

Diss. (sammanfattning) Stockholm : Karol. inst. / Härtill 5 uppsatser.