ABSTRACT
We investigate the nonlinear mechanical properties of GaAs nanowires with anisotropic cross-section. Fundamental and second order flexural modes are studied using laser interferometry with good agreement found between experiment and theory describing the nonlinear response under mechanical excitation. In particular, we demonstrate that the sign of the nonlinear coupling between orthogonal modes is dependent on the cross-section aspect ratio. The findings are of interest for applications such as amplitude to frequency conversion and vectorial force sensing.
ABSTRACT
Patellar fractures are rare in children and usually result from high-energy trauma. Treatment guidelines generally are the same as for patellar fractures in adults. Between 1942 and 1987, 66 children with patellar fractures were treated. Exclusion of those with < 2-year follow-up, osteochondral fractures, or incomplete records left 24 patients for long-term follow-up. Overall results were good in 13, fair in eight, and poor in three. Children with fractures of the ipsilateral femur and/or tibia and those with comminuted, displaced fractures had the poorest results.
Subject(s)
Fractures, Bone/diagnostic imaging , Patella/injuries , Adolescent , Child , Female , Femoral Fractures/complications , Follow-Up Studies , Fractures, Bone/complications , Fractures, Bone/therapy , Humans , Male , Patella/diagnostic imaging , Prognosis , Radiography , Tibial Fractures/complicationsABSTRACT
Focal myositis is a rare, benign, pseudotumor of skeletal muscle that is usually seen as a steadily enlarging soft tissue tumor in an otherwise healthy patient. Focal involvement of muscle with severe myopathic and inflammatory changes characterize the histology. The natural course of this disorder is spontaneous regression. We report the case of a 7-year-old girl with focal myositis of the index lumbrical muscle. This is the first reported incidence of focal myositis that involves muscle of the hand.
Subject(s)
Hand , Myositis/pathology , Child , Female , Hand/pathology , Hand/surgery , Humans , Myositis/surgeryABSTRACT
Two cases of severe foreign body reaction to polymeric debris occurred following cemented total hip arthroplasty. The debris consisted of microfragments of both polyethylene and polymethylmethacrylate. Microfragments are believed to be primarily responsible for the extensive lytic reactions, which represent an extreme degree of the chronic inflammatory response that is commonly associated with loosening of cemented total hip arthroplasties. A schematic representation of the pathogenesis of component loosening, including the foreign body reaction, illustrates the relationship of this phenomenon to the general problem of aseptic loosening. Revision arthroplasty was successful in both cases, followed for a period of nine and 16 months, respectively.
