The human oviduct epithelium primarily consists of ciliated cells and secretory cells. Solitary cilia usually extend from the apical surface of the secretory cells. We investigated the localization of gamma-tubulin in the ciliary basal apparatus of both cell types by fluorescence immunohistochemistry and immunoelectron microscopy. In addition to basal bodies, gamma-tubulin was identified in the lateral basal foot, especially the basal foot cap. This observation is consistent with previous observations that microtubules radiate from the basal foot and the basal foot serves as the microtubule organizing centre.

The human oviduct epithelium is a simple columnar structure that consists primarily of ciliated and secretory cells. Solitary cilia usually extend from the apical cell surface of secretory cells. By injecting crude preparations of striated rootlets into rats, we successfully obtained six monoclonal antibodies (R38, R67, R95, R149, R155, R213) that commonly labeled ciliary rootlets. Using these antibodies, proteins of 205-215 kDa were identified by immunoblotting. Using a clone, R67, we investigated the morphology of the striated rootlets associated with solitary cilia by immunocytochemistry. It was found that the shapes of the rootlets were not simple but varied considerably. The rootlets had branched, radiated, arched, and looped shapes. This is the first report of the rootlets having a variety of shapes. The 205-to 215-kDa antigens identified by the six different antibodies were mostly localized to dark bands of striations, suggesting that they are constitutive components of dark striations of the rootlet.

Bipolar degradation, which is caused by the expansion of stacking faults (SFs) during operation, has been a serious issue in 4H-SiC power devices. To evaluate the threshold minority carrier density of SF expansion, ρth, Maeda et al. proposed a theoretical model based on quantum well action and dislocation theory. This model includes SF energy variations, electronic energy lowering due to carrier trapping, and resolved shear stress applied to partial dislocations, τrss. Though the SF energy and the electric energy lowering were quantitatively established, the effect of τrss has not been discussed well yet. In this study, we first conducted theoretical predictions of the effect of τrssonρth. Then, based on our previous experiment on the dependence of threshold current density on mechanical external stress, we investigated the dependence of ρthonτrss. We conducted submodeling finite element analysis to obtain τrss induced by both residual stress due to the fabrication process and experimentally applied external stress. Finally, we obtained ρth at the origin of SF expansion from the experimentally measured threshold current density using device simulation. It was found that the dependence of ρthonτrss was almost linear. Its gradient was −0.04 ± 0.01 × 1016 cm−3/MPa, which well agrees with the theoretical prediction of −0.03 ± 0.02 × 1016 cm−3/MPa. Our study makes possible a comprehensive evaluation of the critical condition of bipolar degradation.

Expansion of a single Shockley stacking fault (SSF) during forward-current operation decreases the reliability of 4H-SiC bipolar devices. We propose a practical method for analyzing the defect evolution of SSF expansion based on free energy according to current density, temperature, and resolved shear stress conditions. The free energy includes chemical potential and elastic strain energy. Specifically, the chemical potential is related to the driving force for the formation of SSFs by temperature and current, and the elastic strain energy corresponds to the driving force for dislocations that form SSFs under the applied stress. It was confirmed that the proposed multiphysics method could well simulate SSF evolution when stress and current were applied. Furthermore, the results suggest that quantum well action, in which electrons in n-type 4H-SiC enter SSF-induced quantum well states to lower the energy of the dislocation system, affects the driving force of SSF formation.