A cellular model of memory reconsolidation involves reactivation-induced destabilization and restabilization at the sensorimotor synapse in Aplysia.

The memory reconsolidation hypothesis suggests that a memory trace becomes labile after retrieval and needs to be reconsolidated before it can be stabilized. However, it is unclear from earlier studies whether the same synapses involved in encoding the memory trace are those that are destabilized and restabilized after the synaptic reactivation that accompanies memory retrieval, or whether new and different synapses are recruited. To address this issue, we studied a simple nonassociative form of memory, long-term sensitization of the gill- and siphon-withdrawal reflex in Aplysia, and its cellular analog, long-term facilitation at the sensory-to-motor neuron synapse. We found that after memory retrieval, behavioral long-term sensitization in Aplysia becomes labile via ubiquitin/proteasome-dependent protein degradation and is reconsolidated by means of de novo protein synthesis. In parallel, we found that on the cellular level, long-term facilitation at the sensory-to-motor neuron synapse that mediates long-term sensitization is also destabilized by protein degradation and is restabilized by protein synthesis after synaptic reactivation, a procedure that parallels memory retrieval or retraining evident on the behavioral level. These results provide direct evidence that the same synapses that store the long-term memory trace encoded by changes in the strength of synaptic connections critical for sensitization are disrupted and reconstructed after signal retrieval

TNF-α induces vascular insulin resistance via positive modulation of PTEN and decreased Akt/eNOS/NO signaling in high fat diet-fed mice

Abstract\ud \ud Background\ud High fat diet (HFD) induces insulin resistance in various tissues, including the vasculature. HFD also increases plasma levels of TNF-α, a cytokine that contributes to insulin resistance and vascular dysfunction. Considering that the enzyme phosphatase and tension homologue (PTEN), whose expression is increased by TNF-α, reduces Akt signaling and, consequently, nitric oxide (NO) production, we hypothesized that PTEN contributes to TNF-α-mediated vascular resistance to insulin induced by HFD. Mechanisms underlying PTEN effects were determined.\ud \ud \ud Methods\ud Mesenteric vascular beds were isolated from C57Bl/6J and TNF-α KO mice submitted to control or HFD diet for 18 weeks to assess molecular mechanisms by which TNF-α and PTEN contribute to vascular dysfunction.\ud \ud \ud Results\ud Vasodilation in response to insulin was decreased in HFD-fed mice and in ex vivo control arteries incubated with TNF-α. TNF-α receptors deficiency and TNF-α blockade with infliximab abolished the effects of HFD and TNF-α on insulin-induced vasodilation. PTEN vascular expression (total and phosphorylated isoforms) was increased in HFD-fed mice. Treatment with a PTEN inhibitor improved insulin-induced vasodilation in HFD-fed mice. TNF-α receptor deletion restored PTEN expression/activity and Akt/eNOS/NO signaling in HFD-fed mice.\ud \ud \ud Conclusion\ud TNF-α induces vascular insulin resistance by mechanisms that involve positive modulation of PTEN and inhibition of Akt/eNOS/NO signaling. Our findings highlight TNF-α and PTEN as potential targets to limit insulin resistance and vascular complications associated with obesity-related conditions.This work was supported by grants from Fundação de Amparo à Pesquisa\ud do Estado de São Paulo (FAPESP 2013/08216-2-CRID), Coordenação de Aper‑\ud feiçoamento de Pessoal de Nível Superior (CAPES) and Conselho Nacional de\ud Desenvolvimento Científico e Tecnológico (CNPq), Brazil

Audit committee accounting expertise, CEO power, and audit pricing

The Sarbanes–Oxley Act of 2002 (SOX) mandates that all listed firms disclose whether they have a financial expert on the audit committee, highlighting the committee’s expertise. However, some argue that non-accounting financial experts, compared to accounting financial experts, are not sufficient to ensure audit committee effectiveness because the former lack accounting knowledge. Accounting experts on audit committees may require higher audit efforts, while auditors may assess audit committees with accounting financial experts as effective, decreasing audit efforts. This paper first inspects the effect of audit committee accounting expertise on audit fees as a proxy for audit efforts, and then investigates whether the effect is moderated by powerful CEOs. Using post-SOX period data, our results show that, on average, firms with accounting experts on audit committees are more likely to pay higher audit fees, and the effect is less pronounced when a powerful CEO manages a firm

Solubility-driven Polythiophene Nanowires and Their Electrical Characteristics

We demonstrated that interconnected nanofibrillar networks of poly(3-hexylthiophene) (P3HT) thin films with improved crystallinity can be easily fabricated by aging the precursor solution with marginal solvent. Structural analysis revealed that these benefits arise from the improvements in the crystallinity of P3HT in the precursor solution. At dilute concentrations, P3HT molecules grew into near-spherical particles during the aging time. As the aging time increased further, P3HT molecules exhibited one-dimensional growth into rod-like structures. At higher P3HT concentrations and longer P3HT solution aging times, dense nanowires were observed to form gradually, thereby improving the electronic properties of field-effect transistors (FETs) based on these films. This improvement was due to the change in P3HT organization in the precursor solution from a random-coil conformation to an ordered aggregate as a result of aging in a marginal solvent, methylene chloride. At high temperatures, the P3HT molecules were completely solvated and adopted a random-coil conformation, as is observed in good solvents. Whereas upon aging the solution at room temperature, methylene chloride poorly solvated the P3HT molecules such that ordered aggregates of P3HT grew in solution, which improved the molecular ordering of P3HT thin films produced from these solutions. The field-effect mobility of the thin films was, therefore, enhanced without the need for post-treatments.open114044sciescopu

High field-effect mobility pentacene thin-film transistors with nanoparticle polymer composite/polymer bilayer insulators

High field-effect mobility organic thin-film transistors with nanoparticle polymer composite/polymer bilayer insulators were fabricated. A device composed of a polyvinylphenol (PVP) insulator filled with barium strontium titanate (BST) nanoparticles and coated with a thin polystyrene film was found to exhibit a field-effect mobility (1.2 cm(2) V(-1) s(-1) for a pentacene device) and a field-induced current that are superior to those of devices with only a PVP insulator or a BST-filled PVP insulator. These improvements in the performance are due to an increase in the capacitance and a reduction in the interface roughness of the insulator.open113538sciescopu

Solubility-Induced Ordered Polythiophene Precursors for High-Performance Organic Thin-Film Transistors

With the aim of enhancing the field-effect mobility of self-assembled regioregular poly(3-hexylthiophene), P3HT, by promoting two-dimensional molecular ordering, the organization of the P3HT in precursor solutions is transformed from random-coil conformation to ordered aggregates by adding small amounts of the non-solvent acetonitrile to the solutions prior to film formation. The ordering of the precursor in the solutions significantly increases the crystallinity of the P3HT thin films. It is found that with the appropriate acetonitrile concentration in the precursor solution, the resulting P3HT nanocrystals adopt a highly ordered molecular structure with a field-effect mobility dramatically improved by a factor of approximately 20 depending on the P3HT concentration. The improvement is due to the change in the P3HT organization in the precursor solution from random-coil conformation to an ordered aggregate structure as a result of the addition of acetonitrile. In the good solvent chloroform, the P3HT molecules are molecularly dissolved and adopt a random-coil conformation, whereas upon the addition of acetonitrile, which is a non-solvent for aromatic backbones and alkyl side chains, 1D or 2D aggregation of the P3HT molecules occurs depending on the P3HT concentration. This state minimizes the unfavorable interactions between the poorly soluble Ill and the acetonitrile solvent, and maximizes the favorable pi-pi stacking interactions in the precursor solution, which improves the molecular ordering of the resulting P3HT thin film and enhances the field-effect mobility without post-treatment.X11153sciescopu

Structural and optical properties of nitrogen-ion-implanted ZnO nanorods

We present a study of the structural and the optical properties of nitrogen-ion-implanted ZnO nanorods. Vertically-aligned ZnO nanorods were synthesized on Al2O3 substrates by using a catalyst-free metal-organic chemical vapor deposition (MOCVD) procedure. Nitrogen ions with an energy of 120 keV and an ion flux of 1 x 10(16) particles/cm(2) were implanted on the vertically-aligned ZnO nanorods. The structural properties were studied by using various techniques, including field emission transmission electron microscopy (FE-TEM), X-ray diffraction (XRD), and X-ray absorption fine structure (XAFS) analyses. The XRD measurements revealed that the crystalline properties of the nitrogen-ion-implanted ZnO nanorods were comparable with those of the as-grown ZnO nanorods. However, the XAFS analysis demonstrated that the bonding lengths of atomic pairs on the c-axis were slightly elongated and that the ion implantation caused an extra structural disorder of Zn-O pairs. The FE-TEM revealed that the nanorods had structurally-damaged spots along the entire length of the nanorods. nom the photoluminescence (PL) spectra, we observed a considerably weak main donor-acceptor transition peak at 3.02 eV in the temperature range of 5-300 K. The blue shift and the intensity decrease of the main transition peak strongly suggest that the implanted nitrogen ions play a role in the optical property changes of the nanorods.X1112sciescopuskc

DISRUPTED-IN-SCHIZOPHRENIA 1 PLAYS ESSENTIAL ROLES IN MITOCHONDRIA

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Structural and Optical Properties of Hydrogen-ion-implanted ZnO Nanorods

We investigated the micro-structural and the optical properties of H+-ion-implanted ZnO nanorods by using X-ray absorption fine structure (XAFS) measurements at the Zn K edge and photoluminescence (PL) measurements. Vertically-aligned ZnO nanorods were synthesized using metal-organic chemical-vapor deposition and were vertically implanted with hydrogen ions (H+) at an energy of 90 keV and a total flux of 10(16) particles/cm(2). Scanning electron microscopy measurements showed no detectable defects existing in the WE-ion-implanted ZnO nanorods. However, transmission electron microscopy measurements revealed that an amorphous phase existed, particularly near the top parts of the nanorods. X-ray diffraction and XAFS measurements provided further evidence that the nanorods had structural defects due to the H+-ion implantation. PL measurements showed that the transition peak intensity of the H+-ion-implanted ZnO nanorods was decreased dramatically due to the ion implantation.X1154sciescopuskc