Strain modulation spectroscopy

The technique of resonant strain modulation has been applied for the first time to the modulation of optical transitions occurring between levels of the 4f shell of lanthanide ions. This allows changes in signal strength of typically 0.01% of the maximum spectral line height, which results from spectral line shifts smaller than 10-²/(kg/mm²), to be easily detected. After a full description the method is used to obtain the orbit lattice parameters dB₀²/dδ of Pr³⁺ in CaF₂ and SrF₂ hosts. On the assumption of a local cubic lattice these are found to be (-4.5 ± 1.5) x 10 cm and (-5.4 ± 1.0) x 10 cm respectively. The shifts of some optical transitions of CaF₂:Er³⁺are also presented. Application of the method to shifts of the vibronic sided bans of MeF₂:sm²⁺, polarisation studies of the no phonon f-d transitions of Sm²⁺, and to Er³⁺ and Sm²⁺ in different site symmetries, is also discussed

Tissue engineering of the peripheral nervous system

The structure and function of peripheral nerves can be affected by a range of conditions with severe consequences in these patients. Currently, there are several surgical techniques available to treat peripheral nerve defects. Direct repair is the preferred treatment for short nerve gaps, and nerve autografting is the gold standard in critical nerve defects. The autografting is not always available, and the use of allograft, decellularized allograft and nerve conduits are often used with variable success. During the recent years, several outcomes were achieved in peripheral nerve tissue engineering. Promising experimental results have been demonstrated with this novel generation of nerve conduits, mainly composed by biodegradable materials in combination with intraluminal fillers, growth factors and different cell sources