39 research outputs found
On properly integrating the electronic Raman and optical infra-red spectra of HTSC cuprate materials
New electronic Raman and I.R. spectroscopy results from optimally and
overdoped high temperature superconducting (HTSC) cuprate systems are
interpreted in terms of the negative-U, boson-fermion crossover model.
Distinction is made between those features which follow the condensate gap,
2Delta(p), and those that are set by the local-pair binding energy, cursive
U(p). The critical role of doping level psubc = 0.185 is highlighted in
conjunction with the matter of developing quasiparticle incoherence, making
connection here with recent transport and related results. E//c IR results in
magnetic fields parallel and perpendicular to c prove particularly
illuminating. The general scheme developed continues to embrace all
experimental data very satisfactorily.Comment: 23 pages, 4 figure
Does facial soft tissue protect against zygomatic fractures?: results of a finite element analysis
Introduction: Zygomatic fractures form a major entity in craniomaxillofacial traumatology. Few studies have dealt with biomechanical basics and none with the role of the facial soft tissues. Therefore this study should investigate, whether facial soft tissue plays a protecting role in lateral midfacial trauma
A population-specific material model for sagittal craniosynostosis to predict surgical shape outcomes
Sagittal craniosynostosis consists of premature fusion (ossification) of the sagittal suture during infancy, resulting in head deformity and brain growth restriction. Spring-assisted cranioplasty (SAC) entails skull incisions to free the fused suture and insertion of two springs (metallic distractors) to promote cranial reshaping. Although safe and effective, SAC outcomes remain uncertain. We aimed hereby to obtain and validate a skull material model for SAC outcome prediction. Computed
tomography data relative to 18 patients were processed to simulate surgical cuts and spring location. A rescaling model for age matching was created using retrospective data and validated. Design of experiments was used to assess the effect of different material property parameters on the model output. Subsequent material optimization—using retrospective clinical spring measurements—was performed for nine patients. A population-derived material model was obtained and applied to the whole population. Results showed that bone Young’s modulus and relaxation modulus had the largest effect on the model predictions: the use of the population-derived material model had a negligible effect on improving the prediction of on-table opening while significantly improved the prediction of spring kinematics at follow-up. The model was validated using on-table 3D scans for nine patients: the predicted head shape approximated within 2 mm the 3D scan model in 80% of the surface points, in 8 out of 9 patients. The accuracy and reliability of the developed computational model of SAC were increased using population data: this tool is now ready for prospective clinical application