Sparse Bayesian reconstruction method for multispectral bioluminescence tomography

We present a sparse Bayesian reconstruction method based on multiple types of a priori information for multispectral bioluminescence tomography （BLT）. In the Bayesian approach, five kinds of a priori information are incorporated, reducing the ill-posedness of BLT. Specifically, source sparsity characteristic is considered to promote reconstruction results. Considering the computational burden in the multispectral case, a series of strategies is adopted to improve computational efficiency, such as optimal permissible source region strategy and node model of the finite element method. The performance of the proposed algorithm is validated by a heterogeneous three-dimensional （3D） micron scale computed tomography atlas and a mouse-shaped phantom. Reconstructed results demonstrate the feasibility and effectiveness of the proposed algorithm.     

Information Geometry of the Exponential Family of Distributions with Progressive Type-II Censoring

In geometry and topology, a family of probability distributions can be analyzed as the points on a manifold, known as statistical manifold, with intrinsic coordinates corresponding to the parameters of the distribution. Consider the exponential family of distributions with progressive Type-II censoring as the manifold of a statistical model, we use the information geometry methods to investigate the geometric quantities such as the tangent space, the Fisher metric tensors, the affine connection and the α-connection of the manifold. As an application of the geometric quantities, the asymptotic expansions of the posterior density function and the posterior Bayesian predictive density function of the manifold are discussed. The results show that the asymptotic expansions are related to the coefficients of the α-connections and metric tensors, and the predictive density function is the estimated density function in an asymptotic sense. The main results are illustrated by considering the Rayleigh distribution.     

A facile design for multifunctional AIEgen based on tetraaniline derivatives

Aniline oligomers have been widely used in many fields due to their excellent physicochemical properties. Owing to strong intermolecular interactions, their emission is always weakened or quenched when they are in high concentration or aggregated state, which greatly limits their fluorescent applications. Inspired by the concept of aggregation-induced emission(AIE), herein we introduced large steric groups onto the aniline oligomer to prevent the formation of packing structure. In particular, diphenyl vinyl group was bonded with oligomeric tetraaniline by a facile synthetic procedure with high yield. The obtained aniline oligomer derivative exhibited typical AIE features, which was also confirmed by density functional theoretical calculation. More importantly, this AIE oligomer was able to detect Fe~(3+) ions selectively and quantitatively. The fluorescence intensity decreased linearly along with the increment of Fe~(3+) concentration. Moreover, we demonstrated that this AIE oligomer could stain live bacteria, such as E. coli and S. aureus efficiently. All these results suggest that such a readily accessible and multifunctional tetraaniline derivative provides a new platform for the construction of fluorescent materials.     

Separation control in a conical diffuser with an annular inlet: center body wake separation

In many practical applications of conical diffusers, the flow is fed by an annular flow passage formed by a center body. Flow separation, which occurs if the center body ends abruptly, is undesirable because it degrades the diffuser performance. The present experiment utilizes magnetic resonance velocimetry to acquire three-component mean velocity measurements for a set of conical diffusers with an annular inlet. The results show strong coupling between the diffuser wall boundary layer development and the wake of the center body. Coanda blowing is used to mitigate the center body wake separation. The diffuser wall boundary layer is thick in the absence of the central separation bubble and separates when Coanda blowing is too strong.     

Electronic transmission of three-terminal pyrene molecular bridge

This paper investigates theoretically the electronic transmission spectra of the three terminal pyrene molecular bridge and the quantum current distribution on each bond by the tight-binding model based on nonequilibrium Green's function and the quantum current density approach, in which one π molecular orbital is taken into account per carbon atom when the energy levels and HOMO-LUMO gap are obtained. The transmission spectra show that the electronic transmission of the three terminal pyrene molecular bridge depends obviously on the incident electronic energy and the pyrene eigenenergy. The symmetrical and oscillation properties of the transmission spectra are illustrated. A novel plus-minus energy switching function is found. The quantum current distribution shows that the loop currents inside the pyrene are induced, and some bond currents are much larger than the input and the output currents. The reasons why the loop currents and the larger bond currents are induced are the phase difference of the atomic orbits and the degeneracy of the molecular orbits. The calculations illustrate that the quantum current distributions are in good agreement with Kirchhoff quantum current conservation law.