Protecting entanglement from correlated amplitude damping channel using weak measurement and quantum measurement reversal

Based on the quantum technique of weak measurement, we propose a scheme to protect the entanglement from correlated amplitude damping decoherence. In contrast to the results of memoryless amplitude damping channel, we show that the memory effects play a significant role in the suppression of entanglement sudden death and protection of entanglement under severe decoherence. Moreover, we find that the initial entanglement could be drastically amplified by the combination of weak measurement and quantum measurement reversal even under the correlated amplitude damping channel. The underlying mechanism can be attributed to the probabilistic nature of weak measurements.Comment: 11 pages, 5 figures, accepted by Quantum Information Processin

Generalized quaternion groups with the mm-DCI property

A Cayley digraph Cay(G,S) of a finite group $G$ with respect to a subset $S$ of $G$ is said to be a CI-digraph if for every Cayley digraph Cay(G,T) isomorphic to Cay(G,S), there exists an automorphism $\sigma$ of $G$ such that $S^\sigma=T$. A finite group $G$ is said to have the $m$-DCI property for some positive integer $m$ if all $m$-valent Cayley digraphs of $G$ are CI-digraphs, and is said to be a DCI-group if $G$ has the $m$-DCI property for all $1\leq m\leq |G|$. Let $\mathrm{Q}_{4n}$ be a generalized quaternion group of order $4n$ with an integer $n\geq 3$, and let $\mathrm{Q}_{4n}$ have the $m$-DCI property for some $1 \leq m\leq 2n-1$. It is shown in this paper that $n$ is odd, and $n$ is not divisible by $p^2$ for any prime $p\leq m-1$. Furthermore, if $n\geq 3$ is a power of a prime $p$, then $\mathrm{Q}_{4n}$ has the $m$-DCI property if and only if $p$ is odd, and either $n=p$ or $1\leq m\leq p$.Comment: 1

1,3-Bis[4-(4-pyrid­yl)pyrimidin-2-ylsulfan­yl]propane

In the title compound, C21H18N6S2, the dihedral angles between the aromatic rings in the two 4-(4-pyrid­yl)pyrimidine residues are 23.45 (13) and 2.67 (14)°. Whereas one of the C—S—C—C torsion angles corresponds to a staggered conformation, the other is gauche

Efficient Methods for Non-stationary Online Learning

Non-stationary online learning has drawn much attention in recent years. In particular, dynamic regret and adaptive regret are proposed as two principled performance measures for online convex optimization in non-stationary environments. To optimize them, a two-layer online ensemble is usually deployed due to the inherent uncertainty of the non-stationarity, in which a group of base-learners are maintained and a meta-algorithm is employed to track the best one on the fly. However, the two-layer structure raises the concern about the computational complexity -- those methods typically maintain $\mathcal{O}(\log T)$ base-learners simultaneously for a $T$-round online game and thus perform multiple projections onto the feasible domain per round, which becomes the computational bottleneck when the domain is complicated. In this paper, we present efficient methods for optimizing dynamic regret and adaptive regret, which reduce the number of projections per round from $\mathcal{O}(\log T)$ to $1$. Moreover, our obtained algorithms require only one gradient query and one function evaluation at each round. Our technique hinges on the reduction mechanism developed in parameter-free online learning and requires non-trivial twists on non-stationary online methods. Empirical studies verify our theoretical findings.Comment: preliminary conference version appeared at NeurIPS 2022; this extended version improves the paper presentation, further investigates the interval dynamic regret, and adds two applications (online non-stochastic control and online PCA

Effects of shot peening on microstructure evolution and mechanical properties of surface nanocrystal layer on titanium matrix composite

Shot peening (SP) was employed to modify the surface microstructure and mechanical properties of (TiB+TiC)/Ti-6Al-4V titanium matrix composite (TMC). And the microstructure evolution and mechanical properties were characterized and analyzed in detail. Transmission electron microscopy (TEM) results illustrated that the surface nanograins were introduced by the effect of SP and the hindering of reinforcements to the matrix deformation. The nanograins were formed near the reinforcement/matrix interface because the matrix was squeezed by both the shots and the reinforcements. Moreover, with increasing the volume fraction of reinforcements, the smaller nanograins were introduced near the interfaces due to the severe deformation between the matrix and reinforcements, which were caused by the decrease in average distance between two reinforcements. Under the same intensity of SP, the deformation of TiC was more severe than that of TiB, and more dislocations were introduced around TiC. The results were influenced by both the different shapes and distribution of reinforcements, and the impact direction of shots. After SP, the compressive residual stress (CRS) and the hardness in the peened surface layer were improved, which was due to the surface deformation, nanograins and high dislocation density in the nanocrystal layer

FSD-C10, a Fasudil derivative, promotes neuroregeneration through indirect and direct mechanisms.

FSD-C10, a Fasudil derivative, was shown to reduce severity of experimental autoimmune encephalomyelitis (EAE), an animal model of multiple sclerosis (MS), through the modulation of the immune response and induction of neuroprotective molecules in the central nervous system (CNS). However, whether FSD-C10 can promote neuroregeneration remains unknown. In this study, we further analyzed the effect of FSD-C10 on neuroprotection and remyelination. FSD-C10-treated mice showed a longer, thicker and more intense MAP2 and synaptophysin positive signal in the CNS, with significantly fewer CD4(+) T cells, macrophages and microglia. Importantly, the CNS of FSD-C10-treated mice showed a shift of activated macrophages/microglia from the type 1 to type 2 status, elevated numbers of oligodendrocyte precursor cells (OPCs) and oligodendrocytes, and increased levels of neurotrophic factors NT-3, GDNF and BDNF. FSD-C10-treated microglia significantly inhibited Th1/Th17 cell differentiation and increased the number of IL-10(+) CD4(+) T cells, and the conditioned medium from FSD-C10-treated microglia promoted OPC survival and oligodendrocyte maturation. Addition of FSD-C10 directly promoted remyelination in a chemical-induced demyelination model on organotypic slice culture, in a BDNF-dependent manner. Together, these findings demonstrate that FSD-C10 promotes neural repair through mechanisms that involved both immunomodulation and induction of neurotrophic factors

Tris[2-(2-pyridylimino­meth­yl)phenol­ato(0.67−)]europium(III) nitrate

The title compound, [Eu(C12H9.33N2O)3]NO3, was obtained by the reaction of Eu(NO3)·3H2O and the Schiff base ligand 2-(2-pyridylimino­meth­yl)phenol. The Eu atom is located on a threefold rotation axis and is nine-coordinated by three tridentate Schiff base ligands in a distorted tricapped trigonal-prismatic geometry. The O atom at the phenol hydr­oxy group is partially deprotonated and the H atoms are modelled with one-third occupancy according to the space group R . Offset face-to-face π–π [centroid–centroid distance = 3.886 (3) Å] and edge-to-face C—H⋯π inter­actions are found between adjacent mol­ecules. An intra­molecular O—H⋯N hydrogen bond is also present