Osteogenesis imperfecta (OI) is an uncommon genetic bone disease associated with brittle bones and fractures in children and adults. Although OI is most commonly associated with mutations of the genes for type I collagen, many other genes (some associated with type I collagen processing) have now been identified. The genetics of OI and advances in our understanding of the biomechanical properties of OI bone are reviewed in this article. Treatment includes physiotherapy, fall prevention, and sometimes orthopedic procedures. In this brief review, we will also discuss current understanding of pharmacologic therapies for treatment of OI.
Interfacial agents are often used to compatibilize immiscible
polymer blends. They are
known to reduce the interfacial tension, homogenize the morphology, and
improve adhesion between
phases. In this study, two triblock copolymers of
styrene/ethylene−butylene/styrene (SEBS), of different
molecular weights, were used to compatibilize a blend of 80 vol %
polystyrene (PS) and 20% ethylene−propylene rubber (EPR). The emulsification curve, which relates the
average minor phase particle
diameter to the concentration of interfacial agent added, was used to
quantify the effect of the interfacial
agents on the blend morphology. Charpy and Izod impact tests were
performed to determine the effect
of the compatibilization on mechanical properties of the blend and to
establish links between morphology,
interface, and properties. Results suggest that for the lower
molecular weight interfacial agent, a
transition in fracture mechanisms, from fragile to ductile, occurs
around 20% interfacial agent (based on
the volume of the minor phase). This transition, however, is not
observed with the high molecular weight
interfacial agent.
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