No abstract

Actin dynamics provide an important mechanism for the modification of synaptic plasticity, which is regulated by the actin depolymerizing factor (ADF)/cofilin. However, the role of cofilin regulated actin dynamics in memory extinction process is still unclear. Here, we observed that extinction of conditioned taste aversive (CTA) memory led to temporally enhanced ADF/cofilin activity in the infralimbic cortex (IrL) of the rats. Moreover, temporally elevating ADF/cofilin activity in the IrL could accelerate CTA memory extinction by facilitating AMPAR synaptic surface recruitment, whereas inhibition of ADF/cofilin activity abolished AMPAR synaptic surface trafficking and impaired memory extinction. Finally, we observed that ADF/cofilin-regulated synaptic plasticity was not directly coupled to morphological changes of postsynaptic spines. These findings may help us understand the role of ADF/cofilin-regulated actin dynamics in memory extinction and suggest that appropriate manipulating ADF/cofilin activity might be a suitable way for therapeutic treatment of memory disorders.

This paper presents a new approach to composite system reliability analysis. This approach is based on multiobjective particle swarm optimization (PSO), which is used as an intelligent method for scanning the state space. This paper adapts traditional binary PSO to bi-objective binary PSO using load curtailment and state probability as the two objectives to better control the particle dynamics. Another novel feature of this method is that while it utilizes information from failure states to estimate loss of load indices, it also uses information from acceptable states that are encountered to accelerate the convergence of the estimate. The method is demonstrated on the modified IEEE Reliability Test System. It is also shown to compare very favorably with Monte Carlo Simulation.

In the designed copolymers of poly(9-(4-vinyl benzyl)-9H-carbazole) (PVCz)-random-poly(1-(4-nitro-azophenyl)-pyrrole-2, 5-dione) (PMIDO3), carbazole donor and nitro-azobenzene acceptor are introduced into the lateral chains to induce charge transfer under an electric field, and the resulting copolymers have a progressive increase in the nitrogen content to induce filamentary conduction. The fabricated devices with a simple sandwich configuration distinctively exhibit three conductivity states when a negative bias is applied which can be encoded as "0", "1" and "2" for future ternary data storage. The fabricated devices could endure 10 8 read cycles and showed a long retention time of 10 4 s. It is worth noting that the switch-OFF voltages and the OFF-currents are significantly affected by the MIDO3 content within the polymers. The experimental results indicate that charge transfer between the donor and acceptor is responsible for the first switching and the second switching can be attributed to the filamentary rupture. This approach of achieving devices with multistable states through combination of different switching mechanisms in one device may provide a framework for the design and selection of multilevel electrical memory materials in future research.

Three donor−acceptor and twisted anthraquinone azo molecules were synthesized, and the effects of conjugated backbones length, alkyl chains length, and the thermal annealing temperature on the memory characteristics were explored. The device based on Azo-02, which has longer conjugated backbone and alkyl chains, exhibited stable nonvolatile ternary memory behavior as the thermal annealing temperature increased, with basically the same switching threshold voltages and current ratios being ∼1:10 3.43 :10 5.50 . For the "counterpart" molecules (Azo-01 and Azo-03) film, defects appeared or disordered, crystal packing formed as the thermal annealing temperature increased, and the corresponding devices exhibited no obvious conductance switching behaviors. The mechanism related to electrical switching properties and WORM (write-once-read-manytimes) behaviors were elucidated through molecular simulation. The results demonstrated that the long-term thermally stable high-density data-storage devices can be fabricated by adjusting the structures of twisted molecules.

No abstract

This study reports the syntheses, photophysical and electrochemical properties and memory characteristics of triphenylamine (TPA) donor based molecules with progressively weaker terminal acceptor strength (i.e., nitro, acetyl and bromine). The influence of the terminal electron acceptor strength on the film morphology and the devices storage performances was investigated. Nonvolatile ternary ("0", "1" and "2" states) memory devices for high-density data storage could be achieved with a simple ITO/D-A molecule/Al sandwich configuration for TPA-NAP and TPA-AAP. It is noteworthy that the memory device based on TPA-AAP exhibited a better reproducibility and stability with lower operation voltages than that based on TPA-NAP, promising low-power consumption data-storage. These obtained results demonstrate that altering the terminal electron accepting strength in D-A molecules can adjust the film morphology and the device performances for the design of future advanced organic electronic devices.

Gypenosides (GPs) have been reported to have neuroprotective effects in addition to other bioactivities. The protective activity of GPs during stroke and their effects on neural stem cells (NSCs) in the ischemic brain have not been fully elucidated. Here, we test the effects of GPs during stroke and on the NSCs within the subventricular zone (SVZ) of middle cerebral artery occlusion (MCAO) rats. Our results show that pre-treatment with GPs can reduce infarct volume and improve motor function following MCAO. Pre-treatment with GPs significantly increased the number of BrdU-positive cells in the ipsilateral and contralateral SVZ of MCAO rats. The proliferating cells in both sides of the SVZ were glial fibrillary acidic protein (GFAP)/nestin-positive type B cells and doublecortin (DCX)/nestin-positive type A cells. Our data indicate that GPs have neuroprotective effects during stroke which might be mediated through the enhancement of neurogenesis within the SVZ. These findings provide new evidence for a potential therapy involving GPs for the treatment of stroke.