Resistive switching characteristics of a Pt nanoparticle-embedded SiO2-based memory, Thin Solid Films

A Cu/Pt nanoparticle (Pt-NP)-embedded SiO 2 /Pt structure was fabricated to investigate its resistive switching behavior. The resistive switching behavior may be explained by the filament model with the electrochemical reaction. The Pt-NPs enhanced the local electric field to facilitate the filament formation and to decrease the operating voltages. In addition, the non-uniform distribution of the electric field caused the formation of a Cu filament on a Pt-NP, which decreased the switching dispersion. A simulation of the electric field in a Pt-NP embedded SiO 2 layer was used to investigate the influence of Pt-NPs on the resistive switching behavior

A Puzzle-Based Artificial Chromosome Genetic Algorithm for the Traveling Salesman Problem

Conference Name:16th Annual Conference on Technologies and Applications of Artificial Intelligence, TAAI 2011. Conference Address: Chung-Li, Taiwan. Time:November 11, 2011 - November 13, 2011.Taiwanese Association for AI; Japanese Society for Artificial Intelligence (JSAI); National Science Council; MEET TAIWAN; Research Center for Information Technology InnovationThe standard Genetic Algorithm has suffered from the early convergence and trapped into a local optimum when dealing with combinatorial optimization problems. In this research, we introduce a new heuristic approach using the concept of Ant Colony Optimization (ACO) to extract patterns from the chromosomes generated by previous generations for solving the generalized traveling salesman problem. The proposed heuristic is composed of two phases. In the first blocks mining phase, the ACO technique has been adopted to establish a set of non-overlap block archive and the remaining cities (nodes) to be visited in set S. The second phase is a block recombination phase where the set of blocks and the rest of cities are combined to form an artificial chromosome. The generated artificial chromosomes (AC) then will be injected into the SGA process to speed up the convergence. The proposed method is called "Puzzle-based Artificial Chromosome Genetic Algorithm" or "p-ACGA". We demonstrate that p-ACGA performs very well on all TSPLIB problems, which have been solved to optimality by other researchers. The proposed approach can prevent the early convergence of GA and lead the algorithm to explore and exploit the searching space via taking advantage of Artificial Chromosomes which are produced by recombination of the mined blocks. ? 2011 IEEE

Non-Covalently Functionalized Boron Nitride Mediated by a Highly Self-Assembled Supramolecular Polymer

A new method for exfoliation of hexagonal boron nitride (h-BN) into few-layered nanosheets has been developed by employing noncovalent assembly of networks upon association with a supramolecular polymer. In this work, we developed a simple, reliable, effective approach for preparation of exfoliated h-BN nanosheets from bulk h-BN via liquid-phase exfoliation using a low-molecular weight adenine-functionalized polypropylene glycol (A-PPG) supramolecular polymer. A-PPG self-assembled into either long-range ordered lamellar or micelle-like structures on the surface of h-BN because of the strong specific interactions between A-PPG and h-BN. The level of h-BN nanosheet exfoliation could be controlled by adjusting the amount of A-PPG incorporated. This newly developed composite exhibited excellent phase transition behavior and thermal stability, and few-layer thickness with good dispersion of h-BN nanosheets, indicating self-assembled A-PPG functions as an efficient dispersant and stabilizer to manipulate the physical and morphological properties of exfoliated h-BN. This method of producing multifunctional exfoliated h-BN provides a unique paradigm for developing the next generation of thermoconductive devices and solution-processed semiconductors

Self-Assembled pH-Responsive Polymeric Micelles for Highly Efficient, Noncytotoxic Delivery of Doxorubicin Chemotherapy To Inhibit Macrophage Activation: <i>In Vitro</i> Investigation

Self-assembled pH-responsive polymeric micelles, a combination of hydrophilic poly­(ethylene glycol) segments and hydrogen bonding interactions within a biocompatible polyurethane substrate, can spontaneously self-assemble into highly controlled, nanosized micelles in aqueous solution. These newly developed micelles exhibit excellent pH-responsive behavior and biocompatibility, highly controlled drug (doxorubicin; DOX) release behavior, and high drug encapsulation stability in different aqueous environments, making the micelles highly attractive potential candidates for safer, more effective drug delivery in applications such as cancer chemotherapy. In addition, <i>in vitro</i> cell studies revealed the drug-loaded micelles possessed excellent drug entrapment stability and low cytotoxicity toward macrophages under normal physiological conditions (pH 7.4, 37 °C). When the pH of the culture media was reduced to 6.0 to mimic the acidic tumor microenvironment, the drug-loaded micelles triggered rapid release of DOX within the cells, which induced potent antiproliferative and cytotoxic effects <i>in vitro</i>. Importantly, fluorescent imaging and flow cytometric analyses confirmed the DOX-loaded micelles were efficiently delivered into the cytoplasm of the cells via endocytosis and then subsequently gradually translocated into the nucleus. Therefore, these multifunctional micelles could serve as delivery vehicles for precise, effective, controlled drug release to prevent accumulation and activation of tumor-promoting tumor-associated macrophages in cancer tissues. Thus, this unique system may offer a potential route toward the practical realization of next-generation pH-responsive therapeutic delivery systems

Circulating MicroRNAs from Serum Exosomes May Serve as a Putative Biomarker in the Diagnosis and Treatment of Patients with Focal Cortical Dysplasia

Focal cortical dysplasia (FCD) is a congenital malformation of cortical development where the cortical neurons located in the brain area fail to migrate in the proper formation. Epilepsy, particularly medically refractory epilepsy, is the most common clinical presentation for all types of FCD. This study aimed to explore the expression change of circulating miRNAs in patients with FCD from serum exosomes. A total of nine patients with FCD and four healthy volunteers were enrolled in this study. The serum exosomes were isolated from the peripheral blood of the subjects. Transmission electron microscopy (TEM) was used to identify the exosomes. Both exosomal markers and neuronal markers were detected by Western blotting analysis to prove that we could obtain central nervous system-derived exosomes from the circulation. The expression profiles of circulating exosomal miRNAs were assessed using next-generation sequencing analysis (NGS). We obtained a total of 107 miRNAs with dominant fold change (&gt;2-fold) from both the annotated 5p-arm and 3p-arm of 2780 mature miRNAs. Based on the integrated platform of HMDD v3.2, miRway DB and DIANA-miRPath v3.0 online tools, and confirmed by MiRBase analysis, four potentially predicted miRNAs from serum exosomes in patients with FCD were identified, including miR194-2-5p, miR15a-5p, miR-132-3p, and miR-145-5p. All four miRNAs presented upregulated expression in patients with FCD compared with controls. Through Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis and pathway category of four target miRNAs, we found eight possible signaling pathways that may be related to FCD. Among them, we suggest that the mTOR signaling pathway, PI3K-Akt signaling pathway, p53 signaling pathway, and cell cycle regulation and TGF-beta signaling pathway are high-risk pathways that play a crucial role in the pathogenesis of FCD and refractory epilepsy. Our results suggest that the circulating miRNAs from exosomes may provide a potential biomarker for diagnostic, prognostic, and therapeutic adjuncts in patients with FCD and refractory epilepsy

Influence of oxygen concentration on self-compliance RRAM in indium oxide film

This letter investigates various oxygen concentrations in indium oxide films which induce different resistance switching behaviors, including two self-compliance behaviors and a two-step set process. The accumulated oxygen ions produce an oxygen-rich indium oxide film, which can be considered as a variable series resistor after the forming process. Analyses indicate that the lower self-compliance current can be attributed to this larger variable series resistor from the additional oxygen ions. The more significant oxidation reaction decreases the current of the high resistance state. Hence, power consumption can be reduced effectively. ? 2014 IEEE

Peroxisome Proliferator-Activated Receptor γ Coactivator 1α Activates Vascular Endothelial Growth Factor That Protects Against Neuronal Cell Death Following Status Epilepticus through PI3K/AKT and MEK/ERK Signaling

Status epilepticus may cause molecular and cellular events, leading to hippocampal neuronal cell death. Peroxisome proliferator-activated receptor &gamma; coactivator 1-&alpha; (PGC-1&alpha;) is an important regulator of vascular endothelial growth factor (VEGF) and VEGF receptor 2 (VEGFR2), also known as fetal liver kinase receptor 1 (Flk-1). Resveratrol is an activator of PGC-1&alpha;. It has been suggested to provide neuroprotective effects in epilepsy, stroke, and neurodegenerative diseases. In the present study, we used microinjection of kainic acid into the left hippocampal CA3 region in Sprague Dawley rats to induce bilateral prolonged seizure activity. Upregulating the PGC-1&alpha; pathway will increase VEGF/VEGFR2 (Flk-1) signaling and further activate some survival signaling that includes the mitogen activated protein kinase kinase (MEK)/mitogen activated protein kinase (ERK) and phosphatidylinositol 3-kinase (PI3K)/protein kinase B (AKT) signaling pathways and offer neuroprotection as a consequence of apoptosis in the hippocampal neurons following status epilepticus. Otherwise, downregulation of PGC-1&alpha; by siRNA against pgc-1&alpha; will inhibit VEGF/VEGFR2 (Flk-1) signaling and suppress pro-survival PI3K/AKT and MEK/ERK pathways that are also accompanied by hippocampal CA3 neuronal cell apoptosis. These results may indicate that the PGC-1&alpha; induced VEGF/VEGFR2 pathway may trigger the neuronal survival signaling, and the PI3K/AKT and MEK/ERK signaling pathways. Thus, the axis of PGC-1&alpha;/VEGF/VEGFR2 (Flk-1) and the triggering of downstream PI3K/AKT and MEK/ERK signaling could be considered an endogenous neuroprotective effect against apoptosis in the hippocampus following status epilepticus