Experimental Modal Analysis of an In-situ Clavicle.

Clavicle fractures are widespread, and the understanding of their mechanism of occurrence via dynamic loading is important for prevention and design of protection systems. The proposed work will find the natural frequencies and mode shapes of the human clavicles in-situ, by employing experimental modal analysis (EMA) techniques on cadaver clavicles. The clavicle response to impact depends on mechanical energy transmission to the bone and requires an understanding of bone modal characteristics (natural frequencies and mode shapes), as well as the frequency content of the impact force. These dynamic forces include blunt trauma (sport injury or gun stock impact) or falls (i.e. motorcycle accidents) and exhibit a wide frequency spectrum. Clavicle modes are not well understood, and while researchers performed whole body or individual clavicle EMA, no in-situ EMA has been reported. Since an in-situ clavicle features its natural boundary conditions, mode estimation via EMA was more accurate than one performed for an isolated clavicle.The clavicle EMA used instrumented excitation sources (i.e. impact hammer) and sensors (i.e. triaxial accelerometers). The accelerometer responses gathered at several locations along the cadaver clavicle bone and the exciting force was recorded and through time-frequency transformations, the natural frequencies and mode shapes were identified. Mode shape visualization was performed in ModalView software. While material properties of cadaver clavicles may be influenced by embalming, the results, which include natural frequencies, modes and damping constants, would be more relevant than those obtained for isolated clavicles. These results would be used to design protection systems, define global material properties, and calibrate existing analytical models.

EVIDENCE-BASED CURRICULAR CONTENT IMPROVES STUDENT KNOWLEDGE AND CHANGES ATTITUDES TOWARDS TRANSGENDER MEDICINE.

OBJECTIVE: Previous studies have demonstrated that the addition of transgender medicine content to a medical school curriculum increased students' comfort and willingness to treat transgender patients. We aimed to demonstrate that (1) evidence-based curricular content would improve knowledge of and change attitudes towards transgender medicine, and (2) students would consider cross-sex hormone therapy a legitimate treatment option for transgender patients. METHODS: Curricular content with a focus on the biologic evidence for the durability of gender identity was added to the first-year medical program at Boston University School of Medicine. Immediately before and after exposure to the content, students were presented with an assessment of their knowledge of the etiology of gender identity. RESULTS: Immediately following exposure to the content, a significant number of students changed their answer regarding the etiology of gender identity so that the number of correct responses increased from 63% (n = 56) to 93% (n = 121) (P<.001). For transgender treatment, the number of correct responses increased from 20% (n = 56) before exposure to the content to 50% (n = 121) following exposure (P<.001). CONCLUSION: The addition of transgender medicine content to a medical school curriculum with a focus on the biologic evidence for a durable gender identity is an effective means of educating students about the etiology of gender identity and the appropriateness of cross-sex hormone therapy as a treatment for transgender patients.