Treatment of osteoporosis in a mouse model of Duchenne muscular dystrophy using black bear parathyroid hormone

Duchenne muscular dystrophy (DMD) is a progressive disease affecting skeletal and cardiac muscle, as well as bone. Long term disuse and glucocorticoid treatments cause progressive osteoporosis in DMD patients, leading to an increase in fracture incidence. Treatments for osteoporosis in these patients have not been widely explored. Parathyroid hormone (PTH), an anabolic treatment for post-menopausal osteoporosis, could benefit DMD patients by improving skeletal properties and reducing fracture risk. Other PTH analogues are not currently FDA approved to treat osteoporosis, but may have improved osteogenic effects compared to the human analogue. Black bear PTH is especially promising as an osteoporosis treatment for the DMD population. Black bears are unique models of bone maintenance during disuse, since during six months of inactivity (hibernation), they maintain skeletal properties, unlike other hibernators. Additionally, black bear PTH has been correlated to bone formation markers during hibernation, indicating it may be, at least in part, the mechanism by which bears maintain bone during disuse. Employing black bear PTH as a treatment for osteoporosis in DMD patients could greatly improve quality of life for these individuals, and reduce the pain and expense associated with frequent fractures.

Torque converter turbine noise and cavitation noise over varying speed ratio

These investigations will discuss the operational noise caused by automotive torque converters during speed ratio operation. Two specific cases of torque converter noise will be studied; cavitation, and a monotonic turbine induced noise. Cavitation occurs at or near stall, or zero turbine speed. The bubbles produced due to the extreme torques at low speed ratio operation, upon collapse, may cause a broadband noise that is unwanted by those who are occupying the vehicle as other portions of the vehicle drive train improve acoustically. Turbine induced noise, which occurs at high engine torque at around 0.5 speed ratio, is a narrow-band phenomenon that is audible to vehicle occupants currently. The solution to the turbine induced noise is known, however this study is to gain a better understanding of the mechanics behind this occurrence. The automated torque converter dynamometer test cell was utilized in these experiments to determine the effect of torque converter design parameters on the offset of cavitation and to employ the use a microwave telemetry system to directly measure pressures and structural motion on the turbine. Nearfield acoustics were used as a detection method for all phenomena while using a standardized speed ratio sweep test. Changes in filtered sound pressure levels enabled the ability to detect cavitation desinence. This, in turn, was utilized to determine the effects of various torque converter design parameters, including diameter, torus dimensions, and pump and stator blade designs on cavitation. The on turbine pressures and motion measured with the microwave telemetry were used to understand better the effects of a notched trailing edge turbine blade on the turbine induced noise.