Stimuli associated with the presence or absence of amphetamine regulate cytoskeletal signaling and behavior

Drug-paired stimuli rapidly enlarge dendritic spines in the nucleus accumbens (NAcc). While increases in spine size and shape are supported by rearrangement of the actin cytoskeleton and facilitate the synaptic expression of AMPA-type glutamate receptors, it remains unclear whether drug-related stimuli can influence signaling pathways known to regulate these changes in spine morphology. These pathways were studied in rats trained on a discrimination learning paradigm using subcellular fractionation and protein immunoblotting to isolate proteins within dendritic spine compartments in the NAcc shell. An open field chamber was repeatedly associated with amphetamine in one group (Paired) and explicitly unpaired with amphetamine in another (Unpaired). Rats in a third group were exposed to the open field but never administered amphetamine (Control). When administered saline and returned to the open field one week later, Paired rats as expected displayed a conditioned locomotor response relative to rats in the other two groups. NAcc shell tissues were harvested immediately after this 30-minute test. Re-exposing Paired rats to the drug-paired excitatory context significantly decreased p-GluA2(S880), an effect consistent with reduced internalization of this subunit and increased spine proliferation in these rats. In contrast, re-exposing Unpaired rats to the drug-unpaired context, capable of inhibiting conditioned responding in these animals, significantly decreased levels of both actin binding protein Arp2/3 and p-cofilin, consistent with spine volatility, shrinkage, and inhibition of spine proliferation in these rats. These findings show that contextual stimuli previously associated with either the presence or absence of amphetamine differentially regulate cytoskeletal signaling pathways in the NAcc

The effect of the support on the surface composition of PtCu alloy nanocatalysts: In situ XPS and HS-LEIS studies

Pt是一类高效、稳定的催化剂, 但Pt资源短缺且价格昂贵, 限制了其广泛商业化应用. 合金化可以使Pt的用量大为减少,; 且往往能显著提高其催化性能, 因而广泛应用于多相催化和电催化. 其中PtCu合金是一类很有前景的催化剂, Cu资源丰富、价格低廉,; 不仅降低了成本, 而且由于合金效应提高了催化剂的活性和稳定性. 由于合金的粒径、形状、组成及结构是影响其催化性能的重要因素,; 目前研究大多关注这些特征的可控合成.然而, 大多工业金属催化剂都是负载于氧化物上以提高催化性能,; 合金纳米粒子的形貌以及表面组成因与载体作用而发生改变, 也就是所谓的载体效应. 这体现在金属/氧化物界面处,; 能够促进金属粒子分散、改变其形貌甚至化学态、进而改变其催化性能, 其中最具代表性的金属-载体强相互作用. 因此,; 研究不同氧化物载体上合金催化剂的分散度、表面组成、化学态, 特别是不同气氛的影响, 对明确影响催化剂性能的关键控制因素非常重要.; 但是由于多相催化剂的复杂性, 且表面灵敏的测试手段很少, 目前相关报道还不多.; 近年发展起来的高灵敏度低能离子散射谱(HS-LEIS)是表面层灵敏的测试技术,; 可以测定最表面层的组成和含量.本文采用溶剂热共还原法成功制备了均一单相、粒径分布较窄的PtCu_x合金纳米颗粒,; 并运用浸渍法将其负载在TiO_2载体上, 以保证载体上纳米粒子组成的均一性.; 应用准原位X-射线光电子能谱(XPS)和高HS-LEIS对负载的PtCu合金纳米催化剂在不同条件处理后的表面组成和化学状态进行表征,; 发现催化剂的表面组成、分布、形貌和化学状态显著受到载体和处理条件的影响, 同时得到负载和未负载的催化剂表面组成与体相组成关系的相图. 结果表明,; PtCu_x/TiO_2催化剂在连续氧化过程中, Cu被氧化并较好在载体表面铺展, Pt-Cu合金状态被破坏,; Pt可能主要形成单一金属的纳米粒子, 并在界面处形成Ptd+. 在连续还原过程中, 部分被还原的Cu, 与Pt形成富Pt合金粒子.; 催化剂表面层主要是Cu, Pt很少, 与体相组成有很大差别, 说明载体对Cu的分散起到重要作用.Supported PtCu alloys have been broadly applied in heterogeneous catalysis and electrocatalysis owing to their excellent catalytic performance and high CO tolerance. It is important to analyze the outermost surface composition of the supported alloy nanoparticles to understand the nature of the catalytically active sites. In this paper, homogeneous face-centered cubic PtCu nanoparticles with a narrow particle size distribution were successfully fabricated and dispersed on a high-surface-area TiO2 powder support. The samples were oxidized and reduced in situ and then introduced into the ultrahigh vacuum chamber to measure the topmost surface composition by high-sensitivity low-energy ion scattering spectroscopy, and to determine the oxidation states of the elements by X-ray photoelectron spectroscopy. The surface composition and morphology, elemental distribution, and oxidation states of the components were found to be significantly affected by the support and treatment conditions. The PtCu is de-alloyed upon oxidation with CuO wetting on the TiO2 surface and re-alloyed upon reduction. Phase diagrams of the surface composition and the bulk composition were plotted and compared for the supported and unsupported materials. (C) 2017, Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by Elsevier B.V. All rights reserved.National Basic Research Program of China (973 Program) [2013CB933102];; National Natural Science Foundation of China [21273178, 21573180,; 91545204]; Xiamen-Zhuoyue Biomass Energy Co. Ltd

Cold and intense OH radical beam sources

We present the design and performance of two supersonic radical beam sources: a conventional pinhole-discharge source and a dielectric barrier discharge (DBD) source, both based on the Nijmegen pulsed valve. Both designs have been characterized by discharging water molecules seeded in the rare gases Ar, Kr, or Xe. The resulting OH radicals have been detected by laser-induced fluorescence. The measured OH densities are (3.0 ± 0.6) × 10(11) cm(-3) and (1.0 ± 0.5) × 10(11) cm(-3) for the pinhole-discharge and DBD sources, respectively. The beam profiles for both radical sources show a relative longitudinal velocity spread of about 10%. The absolute rotational ground state population of the OH beam generated from the pinhole-discharge source has been determined to be more than 98%. The DBD source even produces a rotationally colder OH beam with a population of the ground state exceeding 99%. For the DBD source, addition of O2 molecules to the gas mixture increases the OH beam density by a factor of about 2.5, improves the DBD valve stability, and allows to tune the mean velocity of the radical beam

Visible-Light-Activated Molecular Nanomachines Kill Pancreatic Cancer Cells

Recently, synthetic molecular nanomachines (MNMs) that rotate unidirectionally in response to UV light excitation have been used to produce nanomechanical action on live cells to kill them through the drilling of holes in their cell membranes. In the work here, visible-light-absorbing MNMs are designed and synthesized to enable nanomechanical activation by 405 nm light, thereby using a wavelength of light that is less phototoxic than the previously employed UV wavelengths. Visible-light-absorbing MNMs that kill pancreatic cancer cells upon response to light activation are demonstrated. Evidence is presented to support the conclusion that MNMs do not kill cancer cells by the photothermal effect when used at low optical density. In addition, MNMs suppress the formation of reactive oxygen species, leaving nanomechanical action as the most plausible working mechanism for cell killing under the experimental conditions

The analysis and fabrication of a novel tin-nickel mixed salt electrolytic coloured processing and the performance of coloured films for Al-12.7Si-0.7Mg alloy in acidic and alkali corrosive environments.

We present for the first time the analysis and fabrication of a novel Tin-Nickel mixed salt electrolytic coloured processing and the performance of coloured films for Al-12.7Si-0.7Mg alloy. This alloy is a novel alloy containing high silicon aluminum alloy extrusion profile which presents excellent mechanical properties as well as broad market prospects. Nevertheless, this kind of material is urgent in need of surface treatment technology. The orthogonal design and single factor tests were applied to optimize for electrolytic coloured technological conditions. By controlling operation conditions, the uniform electrolytic coloured films with different color were obtained. Analysis of microstructure showed that tin particles had been deposited in the coloured film. The coloured films, about 10 mu m thick, were uniform, dense and firmly attached to the substrate. After the coloured samples were maintained at 400AC for 1 h, or quenched from 300AC to room temperature, the coloured films did not change, demonstrating excellent thermostability and thermal shock resistance. Acid and alkali corrosion tests and potentiodynamic polarization showed that corrosion resistance of coloured sample was much better than those of untreated samples. After 240 h neutral salt spray test, protection ratings and appearance ratings of coloured films were Grade 9

Crosstalk between the Circadian Clock and Innate Immunity in Arabidopsis

Plants are frequently challenged by various pathogens. The circadian clock, which is the internal time measuring machinery, has been implicated in regulating plant responses to biotic cues. To better understand the role of the circadian clock in defense control, we tested disease resistance with Arabidopsis mutants disrupted in CCA1 and LHY , two key components of the circadian clock. We found that consistent with their contributions to the circadian clock, cca1 and lhy mutants synergistically affect resistance to both bacterial and oomycete pathogens. Disrupting the circadian clock caused by overexpression of CCA1 or LHY also results in severe disease susceptibility. Thus, our data further demonstrate a direct role of the circadian clock mediated by CCA1 and LHY in defense regulation. We also found that CCA1 and LHY act independently of salicylic acid mediated defense but at least through the down- stream target gene GRP7 to regulate both stomata- dependent and -independent pathways. We further show that defense activation by bacterial infection and the treatment with the elicitor flg22 can also feed back to regulate clock activity. Together our study reveals for the first time reciprocal regulation of the circadian clock and plant innate immunity, significantly expanding our view of complex gene networks regulating plant defense responses and development

Trap-Assisted Charge Injection into Large Bandgap Polymer Semiconductors.

The trap-assisted charge injection in polyfluorene-poly(3,4-ethylenedioxythiophene): poly(styrenesulfonate) (PEDOT:PSS) model systems with an Al or Al/LiF cathode is investigated. We find that inserting 1.3 nm LiF increases electron and hole injections simultaneously and the increase of holes is greater than electrons. The evolution of internal interfaces within polymer light-emitting diodes is observed by transmission electron microscopy, which reveals that the introduction of LiF improves the interface stability at both the cathode (cathode/polymer) and the anode (indium tin oxide (ITO)/PEDOT:PSS). Above-mentioned experimental results have been compared to the numerical simulations with a revised Davids model and potential physical mechanisms for the trap-assisted charge injection are discussed