“Purpose: Repair of nasal and auricular malformation remains an obstacle for clinicians because of poor regenerative capacity of cartilage and limitation of donor sites. In the Current study, we developed a novel approach to regenerate implantable nasal alar cartilage by using marrow precursor cell (MPC) sheet and biodegradable Scaffold of polylactic acid-polyglycolic acid copolymer (PLGA).
Materials and Methods: Rabbit MPCs were expanded and induced by transforming growth fictor-beta to improve chondrocyte phenotype. MPC sheets were obtained by continuous culture and used to wrap PLGA scaffold in the shape of the human nasal alar.
The constructs were incubated in a spinner flask for 4 weeks, and cartilage formation was investigated by gross inspection and histological examination. BAY 73-4506 research buy The constructs were then implanted subcutaneously into a nude mouse. Specimens were harvested and analyzed 4 weeks after implantation.
Results: The results showed that cartilaginous tissue formed and PLGA absorbed during in vitro incubation. Histological analysis showed engineered cartilage consisted of event, spaced lacunae embedded in a matrix rich in proteoglycans, and kept the FK228 ic50 initial shape of the nasal alar. Based on this “”MPC sheet combining polymer strategy,”" implantable nasal alar could be successfully regenerated.
Conclusion: This strategy has the advantage
of high cell transplantation efficiency and great potential for clinical application. (C) 2009 American Association of Oral and Maxillofacial Surgeons”
“The radiation properties of nonpolar AlGaN quantum wells (QWs) were theoretically investigated by comparing them to those of c-plane AlGaN QWs with heavy holes as the top valence band (VB). First, the conditions to find more minimize the threshold
carrier density of c-plane QW laser diodes were explored. A thin well width (similar to 1 nm) and reduction of the Al content in the well layer were important to reduce threshold carrier density because narrow wells suppressed the quantum confined Stark effect and AlGaN with a lower Al content had a lower density of states. Moreover, the emission wavelength was widely controlled by tuning the Al contents of both the well and barrier layers under the proposed conditions. Then the properties of nonpolar AlGaN QWs were investigated. Nonpolar AlGaN had several superior characteristics compared to c-plane QWs, including large overlap integrals, optical polarization suitable for both edge and surface emissions, an almost linearly polarized optical dipole between the conduction band and top VB due to the isolated VBs, and a reduced VB density of state. Finally, the threshold carrier densities of both nonpolar and optimized c-plane QWs were compared as functions of the transition wavelength. At a given wavelength, the threshold of nonpolar QWs was lower than that of c-plane ones.