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© The Royal Society of Chemistry 2016. Single-band red upconversion (UC) emission of Er3+ has been successfully achieved in Yb3+/Er3+ codoped KMgF3 nanocrystals via a nonequivalent substitution strategy, in which lanthanide ions probably aggregate, as evidenced by density functional theory calculations and upconversion dynamic processes. The aggregation of Yb3+/Er3+ would cause large cross-relaxation probabilities among the lanthanide ions when photo-excited, resulting in the disappearance of the green emission and the population of the red emitting level of Er3+. Interestingly, the single-band feature is independent of the dopant concentration and pump power. The possible UC mechanism is discussed in detail according to nanocrystal morphology, ion radii, lattice parameters and decay lifetime studies of the Yb3+-Er3+ doped analogous compounds (KMgF3, KZnF3 and KCdF3). It could be concluded that Yb3+/Er3+ ions tend to aggregate in KMgF3, resulting in the largest ratio of red to green UC emission. This research may give a perspective toward tuning the UC emission of lanthanide ions.

© The Royal Society of Chemistry 2016. Single-band red upconversion (UC) emission of Er3+ has been successfully achieved in Yb3+/Er3+ codoped KMgF3 nanocrystals via a nonequivalent substitution strategy, in which lanthanide ions probably aggregate, as evidenced by density functional theory calculations and upconversion dynamic processes. The aggregation of Yb3+/Er3+ would cause large cross-relaxation probabilities among the lanthanide ions when photo-excited, resulting in the disappearance of the green emission and the population of the red emitting level of Er3+. Interestingly, the single-band feature is independent of the dopant concentration and pump power. The possible UC mechanism is discussed in detail according to nanocrystal morphology, ion radii, lattice parameters and decay lifetime studies of the Yb3+-Er3+ doped analogous compounds (KMgF3, KZnF3 and KCdF3). It could be concluded that Yb3+/Er3+ ions tend to aggregate in KMgF3, resulting in the largest ratio of red to green UC emission. This research may give a perspective toward tuning the UC emission of lanthanide ions.

The insulin-like growth factor receptor I (IGF-IR) plays an essential role in transformation by promoting cell growth and protecting cancer cells from apoptosis. Aberrant IGF-IR signaling is implicated in several types of tumors, including carcinomas of the lung, breast, prostate, pancreas, liver, and colon. However, the contribution of the IGF-IR to the development of the transformed phenotype in urothelial cells has not been clearly established. In this study we demonstrated that the IGF-IR is overexpressed in invasive bladder cancer tissues compared with nonmalignant controls. We have investigated the role of the IGF-IR in bladder cancer by using urothelial carcinoma-derived 5637 and T24 cells. Although activation of the IGF-IR did not appreciably affect their growth, it did promote migration and stimulate in vitro wound closure and invasion. These effects required the activation of the Akt and Mitogen-activated protein kinase (MAPK) pathways as well as IGF-I-induced Akt- and MAPK-dependent phosphorylation of paxillin, which relocated at dynamic focal adhesions and was necessary for promoting motility in bladder cancer cells. Our results provide the first evidence for a role of the IGF-IR in motility and invasion of bladder cancer cells and support the hypothesis that the IGF-IR may play a critical role in the establishment of the invasive phenotype in urothelial neoplasia. Thus, the IGF-IR may also serve as a novel biomarker for bladder cancer. Copyright © American Society for Investigative Pathology.