Thermal inflation is a second epoch of exponential expansion at typical energy scales V 1/4 ∼ 10 6∼8 GeV.If the usual primordial inflation is followed by thermal inflation, the primordial power spectrum is only modestly redshifted on large scales, but strongly suppressed on scales smaller than the horizon size at the beginning of thermal inflation, k > k b = a b H b . We calculate the spectral distortion of the cosmic microwave background generated by the dissipation of acoustic waves in this context. For k b 10 3 Mpc −1 , thermal inflation results in a large suppression of the µ-distortion amplitude, predicting that it falls well below the standard value of µ 2 × 10 −8 . Thus, future spectral distortion experiments, similar to PIXIE, can place new limits on the thermal inflation scenario, constraining k b 10 3 Mpc −1 if µ 2 × 10 −8 were found.

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Gene therapy holds a great promise and has been extensively investigated to improve bone formation and regeneration therapies in bone tissue engineering. A variety of osteogenic genes can be delivered by combining different vectors (viral or non-viral), scaffolds and delivery methodologies. Ex vivo & in vivo gene enhanced tissue engineering approaches have led to successful osteogenic differentiation and bone formation. In this article, we review recent advances of gene therapy-based bone tissue engineering discussing strengths and weaknesses of various strategies as well as general overview of gene therapy.