Deep electronic states in ion-implanted Si

In this paper we present an overview of the deep states present after ion-implantation by various species into n-type silicon, measured by Deep Level Transient Spectroscopy (DLTS) and high resolution Laplace DLTS (LDLTS). Both point and small extended defects are found, prior to any anneal, which can therefore be the precursors to more detrimental defects such as end of range loops. We show that the ion mass is linked to the concentrations of defects that are observed, and the presence of small interstitial clusters directly after ion implantation is established by comparing their behaviour with that of electrically active stacking faults. Finally, future applications of the LDLTS technique to ion-implanted regions in Si-based devices are outlined.</p

Restoration of plakoglobin expression in bladder carcinoma cell lines suppresses cell migration and tumorigenic potential

The reduction or loss of plakoglobin expression in late-stage bladder cancer has been correlated with poor survival where upregulation of this catenin member by histone deacetylase inhibitors has been shown to accompany tumour suppression in an in vivo model. In this study, we directly addressed the question of the role of plakoglobin in bladder tumorigenesis following restoration, or knockdown of expression in bladder carcinoma cell lines. Restoration of plakoglobin expression resulted in a reduction in migration and suppression of tumorigenic potential in vivo. Immunocytochemistry revealed cytoplasmic and membranous localisation of plakoglobin in transfectants with <1% of cells displaying detectable nuclear localisation of plakoglobin. siRNA knockdown experiments targeting plakoglobin, revealed enhanced migration in all cell lines in the presence and absence of E-cadherin expression. In bladder cell lines expressing low levels of plakoglobin and desmoglein-2, elevated levels of desmoglein-2 were detected following restoration of plakoglobin expression in transfected cell lines. Analysis of wnt signalling revealed no activation event associated with plakoglobin expression in the bladder model. These results show that plakoglobin acts as a tumour suppressor gene in bladder carcinoma cells and the silencing of plakoglobin gene expression in late-stage bladder cancer is a primary event in tumour progression