We demonstrate that crown ether-assisted ligand replacement on Fe3O4 NPs using halide salts leads to quantitative stripping of an existing stabilizer shell with unprecedented (complete) efficiency; this allows subsequent re-grafting of functional ligands at maximal surface density. The mechanism of the anion-driven ligand replacement is elucidated by varying the halide salt and the versatility ...

Matrix stiffness has been shown to play an important role in modulating various cell fate processes such as differentiation and cell cycle. Given that the stiffness can be easily tuned by varying the crosslinking density, poly(ethylene glycol) (PEG) hydrogels have been widely used as an artificial cell niche. However, little is known about how changes in the hydrogel crosslinking density may af...

To ensure that social networks (e.g. opinion consensus, cooperative estimation, distributed learning and adaptation etc.) proliferate and efficiently operate, the participating agents need to collaborate with each other by repeatedly sharing information. However, sharing information is often costly for the agents while resulting in no direct immediate benefit for them. Hence, lacking incentives...

There has been much research on network flows over time due to their important role in real world applications. This has led to many results, but the more challenging continuous time model still lacks some of the key concepts and techniques that are the cornerstones of static network flows. The aim of this paper is to advance the state of the art for dynamic network flows by developing the cont...

OVER AN ARBITRARILY VARYING CHANNEL Rudolf Ahlswede and Ning Cai Abstract It is well{known that the deterministic code capacity (for the average error probability criterion) of an arbitrarily varying channel (AVC) either equals its random code capacity or zero. Here it is shown that if two components of a correlated source are additionally available to the sender and receiver, respectively, the...

{ With the fast growing uses of GPS-equipments, mobile users can more easily determine where they are located. These physical location information may play an important role in a wireless ad hoc network formed by a collection of wireless mobile hosts, in the absence of any xed infrastructure. Performance overhead considerations are more important for ad hoc network environments because of the t...

In this paper, we present a new method for modeling timeevolving correlation networks, using a Mean Reversion Autoregressive Model, and apply this to stock market data. The work is motivated by the assumption that the price and return of a stock eventually regresses back towards their mean or average. This allows us to model the stock correlation time-series as an autoregressive process with a ...

Relational data—like graphs, networks, and matrices—is often dynamic, where the relational structure evolves over time. A fundamental problem in the analysis of time-varying network data is to extract a summary of the common structure and the dynamics of the underlying relations between the entities. Here we build on the intuition that changes in the network structure are driven by dynamics at ...

We propose several econometric measures of connectedness based on principal-components analysis and Granger-causality networks, and apply them to the monthly returns of hedge funds, banks, broker/dealers, and insurance companies. We find that all four sectors have become highly interrelated over the past decade, likely increasing the level of systemic risk in the finance and insurance industrie...