A new experimental setup for combined fast differential scanning calorimetry and X-ray photon correlation spectroscopy.

Synchrotron-radiation-based techniques are a powerful tool for the investigation of materials. In particular, the availability of highly brilliant sources has opened the possibility to develop techniques sensitive to dynamics at the atomic scale such as X-ray photon correlation spectroscopy (XPCS). XPCS is particularly relevant in the study of glasses, which have been often investigated at the macroscopic scale by, for example, differential scanning calorimetry. Here, we show how to adapt a Flash calorimeter to combine XPCS and calorimetric scans. This setup paves the way to novel experiments requiring dynamical and thermodynamic information, ranging from the study of the crystallization kinetics to the study of the glass transition in systems that can be vitrified thanks to the high cooling rates reachable with an ultrafast calorimeter.

Stochastic atomic acceleration during the X-ray-induced fluidization of a silica glass.

The X-ray-induced, nonthermal fluidization of the prototypical SiO2 glass is investigated by X-ray photon correlation spectroscopy in the small-angle scattering range. This process is initiated by the absorption of X-rays and leads to overall atomic displacements which reach at least few nanometers at temperatures well below the glass transition. At absorbed doses of ∼5 GGy typical of many modern X-ray-based experiments, the atomic displacements display a hyperdiffusive behavior and are distributed according to a heavy-tailed, Lévy stable distribution. This is attributed to the stochastic generation of X-ray-induced point defects which give rise to a dynamically fluctuating potential landscape, thus providing a microscopic picture of the fluidization process.

Congenital pseudarthrosis of the clavicle: a report on 27 cases.

HYPOTHESIS: We aimed to report our experience in treating congenital pseudarthrosis of the clavicle (CPC). MATERIALS AND METHODS: A retrospective search of the archive of our institute was performed; 27 cases (12 male and 15 female patients) affected by CPC were recorded. Among these patients, 19 underwent surgical intervention for cosmetic appearance between 1960 and 2015. Of 19 patients, 18 were treated by pseudarthrosis resection and stabilization with a Kirschner wire, whereas in 1 case, the osteosynthesis was performed with a plate. Iliac crest bone autograft was used in 15 patients, whereas 4 patients were treated with a fibular allograft. RESULTS: The mean follow-up period was 36.3 ± 49.1 months. Bone healing was achieved in 14 of 19 operated cases (74%); none of the patients had complaints regarding cosmetic abnormalities or unesthetic appearance. All the operated patients were pain free, range of motion was complete, and no other subjective anomalies were found. No vascular or neurologic complications were observed. However, the use of allograft was associated with high rates of nonunion in this case series (P = .037). CONCLUSION: CPC can be satisfactorily treated by K-wire fixation and autologous iliac crest bone grafting, which showed better results in terms of functional and cosmetic outcome.

Outcomes after surgical treatment of missed Monteggia fractures in children.

BACKGROUND: Chronic dislocation of the radial head treatment in Monteggia fracture dislocation is still controversial. We present a large series of patients treated in our Institution. MATERIALS AND METHODS: The outcome of 22 children treated surgically between 1988 and 2011 for post-traumatic chronic radial head dislocation is reported. There were 12 girls and 10 boys with a mean age at surgery of 7.2 years (4.1-13.6). The mean interval between injury and treatment was 15.7 months (1-128). Nine patients underwent open reduction with removal of interposed tissue and repair (7) or Bell-Tawse reconstruction (2) of the annular ligament. Ten patients underwent osteotomy, gradual lengthening and angulation of the ulna by external fixation. Two patients underwent angular osteotomy of the proximal ulna with open wedge, open reduction in the radial head and reconstruction of the annular ligament. One patient admitted to the hospital 10 years after injury underwent radial head excision at 13.7 years of age. RESULTS: After a mean follow-up of 5.5 years (1-24.3), the radial head stayed reduced in 15 patients and subluxated in 5. In one case, redislocation occurred. All patients but five were pain-free. The elbow performance score (Kim score) was excellent in 14 cases, good in four and fair in four, with a mean score of 91, corresponding to a good result. Complications included a transient posterior interosseus nerve palsy (1), and one non-union of the ulna. DISCUSSION AND CONCLUSION: Chronic Monteggia lesions must be treated. The clinical outcomes are usually better than the congruency of the radiocapitellar joint.