• Journal of Veterinary Clinics
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• v.37 no.3
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• pp.157-162
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• 2020

A 6-year-old Thoroughbred mare presented to the Korea Racing Authority Equine Hospital with dropping of the left front fetlock due to an injury sustained while racing. Radiographic examination revealed a comminuted fracture of both proximal sesamoid bones of the affected fetlock. Arthrodesis of the fetlock joint using a broad dynamic compression plate with a tension band wire was performed as a salvage procedure for the future use as a broodmare. After surgery, however, a delayed union of the bones and surgical site infection was present for a prolonged period. Staphylococcus aureus was persistently identified from the surgical site, and antimicrobial therapies were based on antibiotic sensitivity tests, including regional perfusions. The removal and replacement of surgical implants associated with seropurulent discharge was based on coordinating the development of fetlock ankylosis and infection control over 13 months. Firstly, seven screws associated with surgical drainage were replaced and bone morphogenetic protein-2 (BMP-2) and local antibiotics were placed into the surgical site to accelerate bone fusion at postoperative month 7. Further six screws, along with drainage, were removed at postoperative month 10. The plate and screws were removed from the limb due to the progression of bone fusion at postoperative month 13; BMP-2 and local antibiotics were also used. Delayed healing of arthrodesis due to surgical site infection and implant instability were treated by implant removals and antibiotic therapies, and the horse eventually showed improved weight-bearing ability of the affected limb.

• Journal of the Korean Geotechnical Society
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• v.22 no.11
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• pp.55-64
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• 2006

It is very Important to predict the damage zone of a rock mass induced by blasting for the excavation of an underground cavity such as a tunnel, as the damage zones incur mechanical and hydraulic instability of the rock mass potentially. Complicated blasting processes that can hinder the proper characterization of the damage zone can be effectively represented by two loading mechanisms. The first mechanism is the dynamic impulsive load-generating stress waves that radiate outwards immediately after detonation. This load creates a crushed annulus along with cracks around the blasthole. The second is the gas pressure that remains for an extended time after detonation. As the gas pressure reopens some arrested cracks and extends these, it contributes to the final structure of the damage zone induced by the blasting. This paper presents a simple method to evaluate the damage zone induced by gas pressure during rock blasting. The damage zone is characterized by analyzing crack propagations from the blasthole. To do this, a model of a blasthole with a number of radial cracks that are equal in length in a homogeneous infinite elastic plane is considered. In this model, crack propagation is simulated through the use of only two conditions: a crack propagation criterion and the mass conservation of the gas. The results show that the stress intensity factor of a crack decreases as the crack propagates from the blasthole, which determines the crack length. In addition, it was found that the blasthole pressure continues to decrease during crack propagation.