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Abstract: Valproate (VPA) is a widely used anticonvulsant and mood-stabilizing drug. Recent studies have shown that VPA could reduce amyloid-β generation, and improve memory deficits in transgenic mouse models of Alzheimer''s disease (AD). However, whether VPA affects tau phosphorylation and the underlying mechanism has not been established. Here, we showed that systemic treatment of APP and presenilin 1 double transgenic mice with VPA (50mg/kg, once a day for 12weeks), significantly reduced the levels of tau phosphorylation at the sites of Thr205, Ser396 and Thr231. Meanwhile, VPA treatment markedly reduced the activities of cyclin-dependent kinase 5 (CDK5) and glycogen synthase kinase 3β (GSK3β), two protein kinases involved in abnormal hyperphosphorylation of tau. In an okadaic acid-induced tau hyperphosphorylation SH-SY5Y cell model, the anti-tau-phosphorylation effect of VPA was further confirmed, accompanied by a marked decrease in the activities of CDK5 and GSK3β. Our present data suggest that the inhibitory effects of VPA on tau hyperphosphorylation might be mediated through both CDK5 and GSK3β signaling pathways. [Copyright &y& Elsevier]

A neighbour-based coordination scheme is proposed for a multi-agent system with multiple leaders. Under assumptions of the connectivity of the interconnection topology and a simple first-order dynamics model for each mobile agent, the results show that all the agents will flock to the polytope region formed by the leaders. [ABSTRACT FROM AUTHOR]

Abstract: We investigate the conductivity of graphene nanoribbons with zigzag edges as a function of Fermi energy in the presence of the impurities with different potential range. The dependence of displays four different types of behavior, classified to different regimes of length scales decided by the impurity potential range and its density. Particularly, low density of long range impurities results in an extremely low conductance compared to the ballistic value, a linear dependence of and a wide dip near the Dirac point, due to the special properties of long range potential and edge states. These behaviors agree well with the results from a recent experiment by Miao et al. [Science 317 (2007) 1530 (SOM)]. [Copyright &y& Elsevier]

A key prediction of the SO(5) theory is the antiferromagnetic vortex state. Recent neutron scattering experiment on LSCO superconductors revealed enhanced antiferromagnetic order in the vortex state. Here we review theoretical progress since the original proposal and present a theory of static and dynamic antiferromanetic vortices in LSCO superconductors. It is shown that the antiferromagnetic region induced by the vortices can be greater than the coherence length, due to the light effective mass of the dynamic antiferromagnetic fluctuations at optimal doping, and close proximity to the antiferromagentic state in the underdoped regime. Systematic experiments are proposed to unambiguously determine that the field induced magnetic scattering originates from the vortices and not from the bulk. [Copyright &y& Elsevier]

Enantioselective alkynylation of cyclic N-sulfonyl α-ketiminoesters with terminal alkynes was developed by using an Ni(ClO4)2/(R)-DTBM-Segphos complex as a catalyst. A range of propargylic amides bearing quaternary stereocenters were afforded in excellent enantioselectivities (up to 97% ee). Theoretical studies revealed that this reaction proceeded via a Friedel–Crafts-type reaction pathway. [ABSTRACT FROM AUTHOR]

Background: An increasing number of studies have demonstrated of that diabetes mellitus (DM) is associated with an increased prevalence of Alzheimer disease (AD), the underlying mechanisms are still obscure. Methods: We developed a streptozotocin (STZ)-induced diabetic AD transgenic mouse model and evaluated the effect of hyperglycemia on senile plaque formation. Results: Our data showed that administration of STZ increased the level of blood glucose and increased the advanced glycation end products (AGEs) in brain tissue, and further enhanced the expression levels of the receptor for AGEs (RAGE) and the nuclear factor-kappa B (NF-κB) in the brain, and accelerated the senile plaque formation in the transgenic mice. Our results showed that STZ-induced insulin-deficient hyperglycemia caused the pathophysiology of AD in APP/PS1 transgenic mice by modulating the AGEs/RAGE/NF-κB pathway. Conclusions: Our study suggests that there is a close linkage of DM and cerebral amyloidosis in the pathogenesis of AD. [ABSTRACT FROM AUTHOR]

Mn-based superconductors are very rare and their superconductivity has only been reported in three-dimensional MnP and quasi-one-dimensional KMn6Bi5 and RbMn6Bi5 with [Mn6Bi5]âˆ' columns under high pressures. Here we report the synthesis, magnetism, electrical resistivity, and specific heat capacity of the newly discovered quasi-one-dimensional NaMn6Bi5. Compared with other A Mn6Bi5 (A = K, Rb, and Cs), NaMn6Bi5 has abnormal Bi-Bi bond lengths and two antiferromagnetic-like transitions at 47.3 K and 51.8 K. Anisotropic resistivity and low-temperature non-Fermi liquid behavior are observed. Heat capacity measurement reveals that the Sommerfeld coefficient for NaMn6Bi5 is unusually large. Using first-principles calculations, an unusual enhancement of density of states near the Fermi level is demonstrated for NaMn6Bi5. The features make NaMn6Bi5 a more suitable platform to explore the interplay of magnetism and superconductivity. [ABSTRACT FROM AUTHOR]

We derive an effective topological field theory model of the four dimensional quantum Hall liquid state recently constructed by Zhang and Hu. Using a generalization of the flux attachment transformation, the effective field theory can be formulated as a U(1) Chern–Simons theory over the total configuration space CP3, or as a SU(2) Chern–Simons theory over S4. The new quantum Hall liquid supports various types of topological excitations, including the 0-brane (particles), the 2-brane (membranes), and the 4-brane. There is a topological phase interaction among the membranes which generalizes the concept of fractional statistics. [Copyright &y& Elsevier]

Graphical abstract Abstract We performed angle-resolved photoemission spectroscopy studies on a series of FeTe 1− x Se x monolayer films grown on SrTiO 3. The superconductivity of the films is robust and rather insensitive to the variations of the band position and effective mass caused by the substitution of Se by Te. However, the band gap between the electron- and hole-like bands at the Brillouin zone center decreases towards band inversion and parity exchange, which drive the system to a nontrivial topological state predicted by theoretical calculations. Our results provide a clear experimental indication that the FeTe 1− x Se x monolayer materials are high-temperature connate topological superconductors in which band topology and superconductivity are integrated intrinsically. [ABSTRACT FROM AUTHOR]

[Display omitted] • Melatonin and trientine were formed into a new compound melatonin-trientine (TM). • TM combines the functions both of antioxidant effects and chelate excessive metal ions. • TM decreases Aβ deposition in the brains of the APP/PS1 mice. • TM promotes APP non-amyloidogenic processing. • TM blocks tau hyperphosphorylation, neuronal degeneration, neuroinflammation, and oxidative stress. Researchers continue to explore drug targets to treat the characteristic pathologies of Alzheimer's disease (AD). Some drugs relieve the pathological processes of AD to some extent, but the failed clinical trials indicate that multifunctional agents seem more likely to achieve the therapy goals for this neurodegenerative disease. Herein, a novel compound named melatonin-trientine (TM) has been covalently synthesized with the natural antioxidant compounds melatonin and the metal ion chelator trientine. After toxicological and pharmacokinetic verification, we elucidated the effects of intraperitoneal administration of TM on AD-like pathology in 6-month-old mice that express both the β-amyloid (Aβ) precursor protein and presenilin-1 (APP/PS1). We found that TM significantly decreased Aβ deposition and neuronal degeneration in the brains of the APP/PS1 double transgenic mice. This result may be due to the upregulation of iron regulatory protein-2 (IRP2), insulin degrading enzyme (IDE), and low density lipoprotein receptor related protein 1 (LRP1), which leads to decreases in APP and Aβ levels. Additionally, TM may promote APP non-amyloidogenic processing by activating the melatonin receptor-2 (MT2)-dependent signaling pathways, but not MT1. In addition, TM plays an important role in blocking γ-secretase, tau hyperphosphorylation, neuroinflammation, oxidative stress, and metal ion dyshomeostasis. Our results suggest that TM may effectively maximize the therapeutic efficacy of targeting multiple mechanisms associated with AD pathology. [ABSTRACT FROM AUTHOR]

We investigate the electronic structures of FeSe in the presence of different possible orders and spin-orbit coupling (SOC). It is found that only the ferro-orbital order (FO) and the collinear antiferro-magnetism (C-AFM) can simultaneously induce splittings at σ and M. Bicollinear antiferro-magnetism (B-AFM) and SOC have very similar band structures on σ-M near the Fermi level. The temperature T insensitive splitting at σ and the T-dependent splitting at M observed in recent experiments can be explained by the d-wave bond nematic (dBN) order together with SOC. The recent observed Dirac cones and their T-dependence in FeSe thin films can also be well explained by the dBN order together with the band renormalization. Their thickness- and cobalt-doping-dependent behaviors are the consequences of electron doping and reduction of Se height. All these suggest that the nematic order in the FeSe system is the dBN order. [ABSTRACT FROM AUTHOR]

Abstract: This paper is concerned with the consensus problem in directed networks with double-integrator dynamics and non-uniform time-varying communication delays. With the help of Lyapunov–Razumikhin function a necessary and sufficient condition is presented in the case when the delays are non-uniform and time-varying. Simulation results are provided to illustrate the theoretical results. [Copyright &y& Elsevier]

The newly discovered alkali-doped iron selenide superconductors not only reach a superconducting transition temperature as high as 32?K, but also exhibit unique characteristics that are absent from other iron-based superconductors, such as antiferromagnetically ordered insulating phases, extremely high Néel transition temperatures and the presence of Fe vacancies and ordering. These features have generated considerable excitement as well as confusion, regarding the delicate interplay between Fe vacancies, magnetism and superconductivity. Here we report on molecular beam epitaxy growth of high-quality KxFe2?ySe2 thin films and in situ low-temperature scanning tunnelling microscope measurement of their atomic and electronic structures. We demonstrate that a KxFe2?ySe2 sample contains two distinct phases: an insulating phase with well-defined order of Fe vacancies, and a superconducting KFe2Se2 phase containing no Fe vacancies. An individual Fe vacancy can locally destroy superconductivity in a similar way to a magnetic impurity in conventional superconductors. Measurement of the magnetic-field dependence of the Fe-vacancy-induced bound states reveals a magnetically related bipartite order in the tetragonal iron lattice. These findings elucidate the existing controversies on this new superconductor and provide atomistic information on the interplay between magnetism and superconductivity in iron-based superconductors. [ABSTRACT FROM AUTHOR]

We predict that the recently discovered quasi-one-dimensional superconductors, A2Cr3As3 (A=K,Rb), possess strong frustrated magnetic fluctuations and are nearby a novel in-out co-planar magnetic ground state. The frustrated magnetism is very sensitive to the c-axis lattice constant and can thus be suppressed by increasing pressure. Our results qualitatively explain strong non-Fermi liquid behaviors observed in the normal state of the superconductors as the intertwining between the magnetism and superconductivity can create a large quantum critical region in quasi-one-dimensional systems and also suggest that the materials share similar phase diagrams and superconducting mechanism with other unconventional superconductors, such as cuprates and iron-based superconductors. [ABSTRACT FROM AUTHOR]