Introduction: Bone fractures remain a common injury. Nonunion fractures are often a serious complication where delays in tissue regeneration occur. The use of pulsed electromagnetic fields (PEMFs) for treatment has been studied for years, having reportedly been able to enhance bone regeneration. However, as various PEMF parameters can affect cellular properties differently, it is necessary to adjust each PEMF parameter to achieve the optimal regeneration. Methods: Primary rabbit mesenchymal stem cells (rMSCs) were cultured in vitro in two types of media, namely nondifferentiation and osteogenic differentiation media. The effect of various intensities of PEMF was assessed by evaluating properties such as cellular metabolism, proliferation, and osteogenic differentiation at different time points. Results: The findings suggest that PEMFs had no adverse effect on cellular morphology and mineralization. In contrast, increased metabolic activity was observed at higher PEMF intensity, whereas moderate PEMF intensities had the strongest effect on cell proliferation in both types of culture media. A comparison study was also done between the primary rMSCs against the MC3T3-E1 cells from a previously published article. It was shown that PEMFs improved cell metabolism of MSCs, while maintaining the metabolic activity of MC3T3. Conclusions: PEMFs generally improved cell proliferation for both cell types, whereas leaving cell mineralization unaffected. Taken together, it can be understood that the optimal application of PEMF stimulus, along with the right cell types, is indeed crucial in achieving effective bone regeneration in vitro.

Low temperature aqueous chemical synthesis (LT-ACS) of zinc oxide (ZnO) nanorods (NRs) has been attracting considerable research interest due to its great potential in the development of light-emitting diodes (LEDs). The influence of the molar ratio of the zinc acetate (ZnAc): KOH as a ZnO seed layer precursor on the density of interface defects and hence the presence of non-radiative recombination centers in LT-ACS of ZnO NRs/GaN LEDs has been systematically investigated. The material quality of the as-prepared seed layer as quantitatively deduced by the X-ray photoelectron spectroscopy is found to be influenced by the molar ratio. It is revealed by spatially resolved cathodoluminescence that the seed layer molar ratio plays a significant role in the formation and the density of defects at the n-ZnO NRs/p-GaN heterostructure interface. Consequently, LED devices processed using ZnO NRs synthesized with molar ratio of 1:5M exhibit stronger yellow emission (similar to 575 nm) compared to those based on 1:1 and 1:3M ratios as measured by the electroluminescence. Furthermore, seed layer molar ratio shows a quantitative dependence of the non-radiative defect densities as deduced from light-output current characteristics analysis. These results have implications on the development of high-efficiency ZnO-based LEDs and may also be helpful in understanding the effects of the ZnO seed layer on defect-related non-radiative recombination. Published by AIP Publishing.