Agmatine ameliorates manifestation of depression-like behavior and hippocampal neuroinflammation in mouse model of Alzheimer's disease.

Extensive clinical and experimental studies established that depression and mood disorders are highly prevalent neuropsychiatric conditions in Alzheimer's disease (AD). However, its neurochemical basis is not clearly understood. Thus, understanding the neural mechanisms involved in mediating the co-morbidity of depression and AD may be crucial in exploring new pharmacological treatments for this condition. The present study investigated the role of the agmatinergic system in ß-amyloid (Aßß1-42) peptide-induced depression using forced swim test (FST) in mice. Following the 28th days of its administration, Aß1-42 peptide produced depression-like behavior in mice as evidenced by increased immobility time in FST and increased expression of pro-inflammatory cytokines like IL-6 and TNF-α compared to the control animals. The Aß1-42 peptide-induced depression and neuroinflammatory markers were significantly inhibited by agmatine -, moxonidine, 2-BFI and l-arginine by once-daily administration during day 8-27 of the protocol. The antidepressant-like effect of agmatine in Aß1-42 peptide in mice was potentiated by imidazoline receptor I1 agonist, moxonidine and imidazoline receptor I2 agonist 2-BFI at their sub-effective doses. On the other hand, it was completely blocked by imidazoline receptor I1 antagonist, efaroxan and imidazoline receptor I2 antagonist, idazoxan Also, agmatine levels were significantly reduced in brain samples of ß-amyloid injected mice as compared to the control animals. In conclusion, the present study suggests the importance of endogenous agmatinergic system and imidazoline receptors system in ß-amyloid induced a depressive-like behavior in mice. The data projects agmatine as a potential therapeutic target for the AD-associated depression and comorbidities.

Composites of Copper Nanowires in Polyethylene: Preparation and Processing to Materials with NIR Dichroism.

Agglomeration of copper nanowires (aspect ratios on the order of 1000) in polyethylene, commonly a major problem, could be prevented by modification of the nanowires with a surface layer of oleylamine. Nanocomposite films were prepared by mixing nanowire dispersions in organic solvents with polyethylene solutions followed by casting, drying, and sometimes hot pressing. Orientation of the copper nanowires by solid-state drawing of the composites at elevated temperatures led to preferential alignment of the nanowires in the drawing direction. This arrangement gave rise to a uniform dichroism in the near-infrared (NIR) region, which is uncommon in the case of the hitherto reported dichroic nanocomposites. The NIR dichroism is ascribed to the high aspect ratio of the metal wires. Hence, drawing of isotropic nanocomposites with metal wires may serve for the manufacture of NIR polarization filters.

Synthesis, Spray Deposition, and Hot-Press Transfer of Copper Nanowires for Flexible Transparent Electrodes.

We report a solution-phase approach to the synthesis of crystalline copper nanowires (Cu NWs) with an aspect ratio >1000 via a new catalytic mechanism comprising copper ions. The synthesis involves the reaction between copper(II) chloride and copper(II) acetylacetonate in a mixture of oleylamine and octadecene. Reaction parameters such as the molar ratio of precursors as well as the volume ratio of solvents offer the possibility to tune the morphology of the final product. A simple low-cost spray deposition method was used to fabricate Cu NW films on a glass substrate. Post-treatment under reducing gas (5% H2 + 95% N2) atmosphere resulted in Cu NW films with a low sheet resistance of 24.5 Ω/sq, a transmittance of T = 71% at 550 nm (including the glass substrate), and a high oxidation resistance. Moreover, the conducting Cu NW networks on a glass substrate can easily be transferred onto a polycarbonate substrate using a simple hot-press transfer method without compromising on the electrical performance. The resulting flexible transparent electrodes show excellent flexibility ( R/ Ro < 1.28) upon bending to curvatures of 1 mm radius.

Mechanistic Aspects in the Formation, Growth and Surface Functionalization of Metal Oxide Nanoparticles in Organic Solvents.

The synthesis of metal oxide nanoparticles in organic solvents, so-called nonaqueous (or nonhydrolytic) processes represent powerful alternatives to aqueous approaches and have become an independent research field. 10 Years ago, when we published our first review on organic reaction pathways in nonaqueous sol-gel approaches, the number of examples was relatively limited. Nowadays, it is almost impossible to provide an exhaustive overview. Here we review the development of the last few years, without neglecting pioneering examples, which help to follow the historical development. The importance of a profound understanding of mechanistic aspects of nanoparticle crystallization and formation mechanisms can't be overestimated, when it comes to the design of rational synthesis concepts under minimization of trial-and-error experiments. The main reason for the progress in mechanistic understanding lies in the availability of characterization tools that make it possible to monitor chemical reactions from the dissolution of the precursor to the nucleation and growth of the nanoparticles, by ex situ methods involving sampling after different reaction times, but more and more also by in situ studies. After a short introduction to experimental aspects of nonaqueous sol-gel routes to metal oxide nanoparticles, we provide an overview of the main and basic organic reaction pathways in these approaches. Afterwards, we summarize the main characterization methods to study formation mechanisms, and then we discuss in great depth the chemical formation mechanisms of many different types of metal oxide nanoparticles. The review concludes with a paragraph on selected crystallization mechanisms reported for nonaqueous systems and a few illustrative examples of nonaqueous sol-gel concepts applied to surface chemistry.

Assembly of ultrasmall Cu3N nanoparticles into three-dimensional porous monolithic aerogels.

We present for the first time the synthesis of transition metal nitride aerogels, specifically Cu3N aerogels by destabilizing colloidal Cu3N nanoparticles into gels using controlled heat treatment. The resulting aerogels consist of interconnected three-dimensional networks with ultrasmall-sized nanoparticle bridges of a surface area of 381 m(2) g(-1) and only 5% relative density.

Synthesis of CuO and Cu3N Nanoparticles in and on Hollow Silica Spheres.

Copper oxide nanoparticles within hollow mesoporous silica spheres were prepared by binding/adsorbing Cu2+ or [Cu(NH3)4(H2O)2]2+ ions on the surface of carbon spheres, followed by formation of a mesoporous silica shell by sol-gel processing and calcination in air. The CuO nanoparticles can subsequently be converted into Cu3N nanoparticles by nitridation with ammonia. The effect of the different copper precursors, i.e. Cu2+ and [Cu(NH3)4(H2O)2]2+, on the nanocomposites was studied. CuO nanoparticles on the outer surface of hollow silica spheres were obtained by thermal treatment of hollow CuSiO3 spheres in air. Nitridation of the CuSiO3 spheres with ammonia resulted in Cu3N@SiO2 composites, with aggregated Cu3N nanoparticles on hollow silica spheres.