Asymmetric Inheritance and Post-mitotic Fate of Midbodies: A Dissertation

Cytokinesis is the final chapter of cell division and its last page is abscission, the physical separation of two daughter cells. During cytokinesis of vertebrate cells, two future daughter cells are connected by an intercellular bridge within which the midbody (MB) is positioned. Since becoming the focus of intense investigations on cytokinesis completion, MB is now perceived as a complicated organelle where multiple pathways for abscission are targeted and coordinated. However, whether post-mitotic midbodies, the midbody derivatives (MBds), would be retained by either daughter cell post-abscission remains unexplored. In addition, how cells manage the fate of inherited MBds is also unclear or only sketchily proposed. Finally, whether the inherited MBds in cells may play non-cytokinetic roles is also unaddressed. In the first chapter, I review the historical and current understanding of MBs, with emphasis on their roles in cytokinesis whereas potential non-cytokinetic roles are also covered. In the second chapter, the aforementioned three questions are sequentially addressed. First, the newly-formed MBd appears to be inherited by the daughter cell with the older centrosome. Second, MBds are not only inherited but also accumulated in cancer and pluripotent stem cells, but not in normal somatic (differentiated) cells. In normal somatic cells, MBds are within membrane-bound compartments for lysosomemediated degradation via autophagosome engulfment. This partially explains why MBd-accumulation is rarely observed in these cells. In contrast to the previous model, colleagues and I showed that MBd-accumulation correlates well with the autophagosomal-lysosomal activity, but not with the proliferation rate. Finally, the experimental increase of MBd levels appears to enhance the anchorage-independent growth in cancer cells and the efficiency of reprogramming in fibroblasts. In the last chapter, I conclude our findings and discuss future directions in two aspects

Evaluating firms : a Bayesian approach

http://deepblue.lib.umich.edu/bitstream/2027.42/96897/1/BBA_Chen_Tien-Chun_SMS399_Winter_1998_final.pd

Design and Analysis of a Novel 25 GHz Interleaver for DWDM Applications with Two Ring Configurations

We present a novel scheme of an excellent flat-top 25 GHz optical interleaver based on two ring configurations. And the Advanced Systems Analysis Program (ASAP) optical modeling software has been utilized for the interleaver design. The optical path difference for interference and the phase shift are provided by the interferometer with two birefringent crystals and dual-ring arrangement. The proposed structure exhibits the passband utilization of more than 90% and the channel isolation greater than 95 dB within the C-band. Furthermore, we improve the dispersion performance by employing λ/6 wave plates as birefringent compensators for interleavers. The research results illustrate that our proposed scheme with compensator can improve the dispersion of more than 85.8%. Comparing the performance with the previous studies of optical interleavers with birefringent crystal and ring structure, the proposed system can achieve an excellent 25 GHz multichannel filter for dense wavelength division multiplexing (DWDM) transmission systems