3,063 research outputs found
Dibromido{2-morpholino-N-[1-(2-pyridyl)ethylidene]ethanamine-κ3 N,N′,N′′}zinc(II)
In the title complex, [ZnBr2(C13H19N3O)], the ZnII atom is five-coordinated by the three N-donor atoms of the Schiff base ligand and by two Br atoms in a distorted square-pyramidal geometry. The morpholine ring adopts a chair conformation
Learning Agent Communication under Limited Bandwidth by Message Pruning
Communication is a crucial factor for the big multi-agent world to stay
organized and productive. Recently, Deep Reinforcement Learning (DRL) has been
applied to learn the communication strategy and the control policy for multiple
agents. However, the practical \emph{\textbf{limited bandwidth}} in multi-agent
communication has been largely ignored by the existing DRL methods.
Specifically, many methods keep sending messages incessantly, which consumes
too much bandwidth. As a result, they are inapplicable to multi-agent systems
with limited bandwidth. To handle this problem, we propose a gating mechanism
to adaptively prune less beneficial messages. We evaluate the gating mechanism
on several tasks. Experiments demonstrate that it can prune a lot of messages
with little impact on performance. In fact, the performance may be greatly
improved by pruning redundant messages. Moreover, the proposed gating mechanism
is applicable to several previous methods, equipping them the ability to
address bandwidth restricted settings.Comment: accepted as a regular paper with poster presentation @ AAAI20. arXiv
admin note: text overlap with arXiv:1903.0556
Myricetin ameliorates cognitive impairment in 3×Tg Alzheimer’s disease mice by regulating oxidative stress and tau hyperphosphorylation
Background: Alzheimer's disease is characterized by abnormal β-amyloid (Aβ) plaque accumulation, tau hyperphosphorylation, reactive oxidative stress, mitochondrial dysfunction and synaptic loss. Myricetin, a dietary flavonoid, has been shown to exert neuroprotective effects in vitro and in vivo. Here, we aimed to elucidate the mechanism and pathways involved in the protective effect of myricetin.
Methods: The effect of myricetin was assessed on Aβ42 oligomer-treated neuronal SH-SY5Y cells and in 3×Tg mice. Behavioral tests were performed to assess the cognitive effects of myricetin (14 days, ip) in 3×Tg mice. The levels of beta-amyloid precursor protein (APP), synaptic and mitochondrial proteins, glycogen synthase kinase3β (GSK3β) and extracellular regulated kinase (ERK) 2 were assessed via Western blotting. Flow cytometry assays, immunofluorescence staining, and transmission electron microscopy were used to assess mitochondrial dysfunction and reactive oxidative stress.
Results: We found that, compared with control treatment, myricetin treatment improved spatial cognition and learning and memory in 3×Tg mice. Myricetin ameliorated tau phosphorylation and the reduction in pre- and postsynaptic proteins in Aβ42 oligomer-treated neuronal SH-SY5Y cells and in 3×Tg mice. In addition, myricetin reduced reactive oxygen species generation, lipid peroxidation, and DNA oxidation, and rescued mitochondrial dysfunction via the associated GSK3β and ERK 2 signalling pathways.
Conclusions: This study provides new insight into the neuroprotective mechanism of myricetin in vitro in cell culture and in vivo in a mouse model of Alzheimer’s disease
Ukupna kinetika redukcije niskokvalitetnog piroluzita smjesom hemiceluloze i lignina kao redukcijskog sredstva
Manganese is widely used in many fields. Many efforts have been made to recover manganese from low-grade pyrolusite due to the depletion of high-grade manganese ore. Thus, it is of practical significance to develop a clean, energy-saving and environmentally friendly technical route to reduce the low-grade pyrolusite.
The reported results show that biomass wastes from crops, crop waste, wood and wood waste are environmentally friendly, energy-saving, and low-cost reducing agents for roasting reduction of low-grade pyrolusite. Kinetics of the reduction reactions is necessary for an efficient design of biomass reduction of pyrolusite. Therefore, it is important to look for a general kinetics equation to describe the reduction of pyrolusite by different kinds of biomass, because there is a wide variety of biomass wastes, meaning that it is impossible to investigate the kinetics for each biomass waste. In this paper, thermal gravimetric analysis and differential thermal analysis were applied to study the overall reduction kinetics of pyrolusite using a mixture of hemicellulose and lignin, two major components of biomass. Overall reduction process is the overlap of the respective reduction processes. A new empirical equation based on the Johnson–Mehl–Avrami equation can be used to describe the respective reduction kinetics using hemicellulose and lignin as reductants, and the corresponding apparent activation energy is 30.14 kJ mol−1 and 38.91 kJ mol−1, respectively. The overall kinetic model for the reduction of pyrolusite by the mixture of hemicellulose and lignin can be simulated by the summation of the respective kinetics by considering their mass-loss fractions, while a unit step function was used to avoid the invalid conversion data. The obtained results in this work are necessary to understand the biomass reduction of pyrolusite and provide valuable assistance in the development of a general kinetics equation.Ukupna kinetika redukcije piroluzita istraživana je termogravimetrijom i diferencijalnom termogravimetrijom. Kao redukcijsko sredstvo upotrijebljeni su hemiceluloza i lignin, glavni sastojci poljoprivrednog biljnog biootpada, drva i drvnog otpada. Ukupnu redukciju čine isprepleteni pojedinačni redukcijski procesi. Kinetika redukcije piroluzita smjesom hemiceluloze i lignina može se opisati novom empirijskom jednadžbom temeljenoj na jednadžbi Johnson–Mehl–Avrami, a odgovarajuća prividna energija aktivacije iznosi 30.14 kJ mol−1, odnosno 38.91 kJ mol−1. Sveobuhvatna kinetika može se modelirati kao zbroj pojedinačnih udjela uzimajući u obzir masene udjele sastojaka smjese te uz primjenu jedinične odskočne funkcije kako bi se izbjegli nevaljani podaci
Modulation of the thermodynamic, kinetic and magnetic properties of the hydrogen monomer on graphene by charge doping
The thermodynamic, kinetic and magnetic properties of the hydrogen monomer on
doped graphene layers were studied by ab initio simulations. Electron doping
was found to heighten the diffusion potential barrier, while hole doping lowers
it. However, both kinds of dopings heighten the desorption potential barrier.
The underlying mechanism was revealed by investigating the effect of doping on
the bond strength of graphene and on the electron transfer and the coulomb
interaction between the hydrogen monomer and graphene. The kinetic properties
of H and D monomers on doped graphene layers during both the annealing process
(annealing time 300 s) and the constant-rate heating process (heating
rate 1.0 K/s) were simulated. Both electron and hole dopings were
found to generally increase the desorption temperatures of hydrogen monomers.
Electron doping was found to prevent the diffusion of hydrogen monomers, while
the hole doping enhances their diffusion. Macroscopic diffusion of hydrogen
monomers on graphene can be achieved when the doping-hole density reaches
cm. The magnetic moment and exchange splitting were
found to be reduced by both electron and hole dopings, which was explained by a
simple exchange model. The study in this report can further enhance the
understanding of the interaction between hydrogen and graphene and is expected
to be helpful in the design of hydrogenated-graphene-based devices.Comment: Submitte
catena-Poly[[dichloridocopper(II)]-μ-4,4′-bis(benzimidazol-1-yl)biphenyl]
In the title compound, [CuCl2(C26H18N4)]n, the Cu(II) ion is four-coordinated by two N atoms from two 4,4′-bis(benzoimidazol-1-yl)biphenyl ligands and two chloride anions, in a slightly distorted tetrahedral environment. The biphenyl ligand acts as a linear bidentate ligand, connecting the metal atoms into an infinite chain parallel to [101]. In the biphenyl ligand, the two benzene rings make a dihedral angle of 33.19 (7)°
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