Hydrothermal Preparation of Ag/TiO2/GO Nanocomposites with Ammonia-Treated Graphene Oxide for Enhanced Conductivity.

In this study, Ag/TiO2/GO nanocomposites were successfully fabricated by a facile hydrothermal method. Nitrogen-doped GO was prepared using ammonia treatment to improve its conductivity. The Ag/TiO2/GO nanocomposites were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), UV-vis diffuse reflectance spectroscopy (DRS), zeta potential, and photoluminescence spectroscopy (PL). A homogeneous dispersion of Ag/TiO2 nanoparticles was shown on the surface of GO. Increasing the nitrogen doping concentration increased hydrophilicity, thereby improving the conductivity of Ag/TiO2/GO nanocomposites.

Relationship Between Functionalized Multi-Walled Carbon Nanotubes and Damping Properties of Multi-Walled Carbon Nanotubes/Carbon Fiber-Reinforced Plastic Composites for Shaft.

The mechanical properties and damping behavior of carbon fiber-reinforced plastic composites with functionalized multi-walled carbon nanotubes were examined. The functionalized multi-walled carbon nanotubes were blended with epoxy resins to prepare multi-walled carbon nanotubes/carbon fiber-reinforced plastic composites. The dispersion properties of functionalized multi-walled carbon nanotubes in epoxy resins were examined using surface free energy. The mechanical properties of functionalized multi-walled carbon nanotubes/carbon fiber-reinforced plastic composites were measured by interlaminar shear strength and torsion strength. The functionalized multi-walled carbon nanotubes/carbon fiber-reinforced plastic composites had superior mechanical properties due to the increase in dispersion properties of functionalized multi-walled carbon nanotubes in epoxy resins. However, the tan delta values of damping behavior, analyzed by dynamic mechanical analysis, varied with the type of functional groups of functionalized multi-walled carbon nanotubes. The composites obtained from functionalized multi-walled carbon nanotubes obtained through spermidine amidation reaction and carbon fiber-reinforced plastic showed excellent tan delta values due to the flexible segments in side chains.

One-Pot Synthesis of Ag-TiO2/Nitrogen-Doped Graphene Oxide Nanocomposites and Its Photocatalytic Degradation of Methylene Blue.

In this study, we report Ag-TiO2/graphene oxide (GO) nanocomposites prepared by a simple one-pot synthesis using TiO2, AgNO3, and N-doped graphene (NDG). The NDG was synthesized using a microwave-assisted hydrothermal (MHT) method as a function of MHT time. The morphology and structure of Ag-TiO2/GO nanocomposites were characterized by scanning electron microscopy (SEM), transmission electron microscope (TEM), X-ray diffraction (XRD), Raman, and Fourier-transform infrared spectroscopy (FTIR). The photocatalytic activity of Ag-TiO2/GO nanocomposites in visible light was explored using the degradation, of methylene blue (MB) dye under the ultraviolet (UV) light. The result showed that Ag-TiO2/GO-3 was very efficient for the degradation of MB with nitrogen doping time. The degradation efficiency of the photocatalytic nanoparticles after 6 h of irradiation was about 80%. Increasing the N-doping time increased their hydrophilicity, thereby improving the photocatalytic performance of Ag-TiO2/GO nanocomposites.

Effect of Silane Coupling Agent on the Creep Behavior and Mechanical Properties of Carbon Fibers/Acrylonitrile Butadiene Rubber Composites.

In this study, we investigated the effect of the silane coupling agent on the relationship between the surface free energy of carbon fibers (CFs) and the mechanical strength of CFs/acrylonitrile butadiene rubber (NBR) composites. Moreover, the creep behavior of the CF/NBR composites at surface energetic point of view were studied. The specific component of the surface free energy of the carbon fibers was found to increase upon grafting of the silane coupling agent, resulting in an increase in the tensile strength of the CF/NBR composites. On the other hand, the compressive creep strength was found to follow a slightly different trend. These results indicate the possible formation of a complex interpenetrating polymer network depending on the molecular size of the organic functional groups of the silane coupling agent.

Effects of oxyfluorination on surface and mechanical properties of carbon fiber-reinforced polarized-polypropylene matrix composites.

In this work, oxyfluorination treatments on carbon fiber surfaces were carried out to improve the interfacial adhesion between carbon fibers and polarized-polypropylene (P-PP). The surface properties of oxyfluorinated carbon fibers were characterized using a single fiber contact angle, and X-ray photoelectron spectroscopy. The mechanical properties of the composites were calculated in terms of work of adhesion between fibers and matrices and also measured by a critical stress intensity factor (K(IC)). The K(IC) of oxyfluorinated carbon fibers-reinforced composites showed higher values than those of as-received carbon fibers-reinforced composites. The results showed that the adhesion strength between the carbon fibers and P-PP had significantly increased after the oxyfluorination treatments. As the theoretical and practical comparisons, OF-CF-60s showed the best mechanical interfacial performance due to the good surface free energy. This indicates that oxyfluorination produced highly polar functional groups on the fiber surface, resulting in strong adhesion between carbon fibers and P-PP in this composite system.

The characteristics of supramammillary cells projecting to the hippocampus in stress response in the rat.

The hypothalamus-pituitary-adrenocortex (HPA) axis is the central mediator of the stress response. The supramammillary (SuM) region is relatively unique among the hypothalamic structures in that it sends a large, direct projection to the hippocampal formation. It has been shown that mild stress could activate the SuM cells that project to the hippocampus. However, the role of these cell populations in modulating the stress response is not known. The present study examined the effect of stress on different populations of SuM cells that project to the hippocampus by injecting the fluorescent retrograde tracer, fluorogold (FG), into the hippocampus and utilizing the immunohistochemistry of choline acetyltransferase (ChAT), corticotrophin releasing factor (CRF), serotonin (5-HT), glutamate decarboxylase (GAD), tyrosine hydroxylase (TH) and NADPH-d reactivity. Immobilization (IMO) stress (2 hr) produced an increase in the expression of ChAT-immunoreactivity, and tended to increase in CRF, 5-HT, GAD, TH-immunoreactivity and nitric oxide (NO)-reactivity in the SuM cells. Fifty-three percent of 5-HT, 31% of ChAT and 56% of CRF cells were double stained with retrograde cells from the hippocampus. By contrast, a few retrogradely labeled cells projecting to the hippocampus were immunoreactive for dopamine, γ-aminobutyric acid (GABA) and NO. These results suggest that the SuM region contains distinct cell populations that differentially respond to stress. In addition, the findings suggest that serotonergic, cholinergic and corticotropin releasing cells projecting to the hippocampus within the SuM nucleus may play an important role in modulating stress-related behaviors.

Tremella fuciformis enhances the neurite outgrowth of PC12 cells and restores trimethyltin-induced impairment of memory in rats via activation of CREB transcription and cholinergic systems.

The present study examined the effects of Tremella fuciformis (TF) on the learning and memory function and the neural activity in rats with trimethyltin (TMT)-induced memory deficits. The rats were administered saline or TF (TF 25, 50, 100 mg/kg, p.o.) daily for 21 days. The cognitive improving efficacy of TF on the amnesic rats, which was induced by TMT, was investigated by assessing the Morris water maze test and by performing Choline acetyltransferase (ChAT) and cAMP responsive element binding protein (CREB) immunohistochemistry. In order to confirm the underlying mechanisms of the memory enhancing effects of TF, we assessed the neurite outgrowth of PC12 cells. We also administered 18F-fluorodeoxyglucose and performed a PET scan of the frontal lobe. The rats with TMT injection showed impaired learning and memory of the tasks and treatment with TF produced a significant improvement of the escape latency to find the platform in the Morris water maze compared to that of the control group. In the retention test, the TF50 group showed increased time spent around the platform compared to that of the control group. Consistent with the behavioral data, TF50 mg/kg significantly alleviated the loss of ChAT-ir neurons in the hippocampus compared to that of the control group. Treatment with TF significantly increased the CREB positive neurons in the hippocampal CA1 area as compared to that of the control group. In addition, TF treatment (50 mg/kg) increased the glucose uptake approximately sevenfold in the frontal lobe and it significantly promoted neurite outgrowth of the PC12 cells, as compared to that of the controls. These results suggest that TF may be useful for improving the cognitive function via regulation of the CREB signaling pathway and cholinergic system in the hippocampus.

Neuroprotective Effect of Lucium chinense Fruit on Trimethyltin-Induced Learning and Memory Deficits in the Rats.

In order to the neuroprotective effect of Lycium chinense fruit (LCF), the present study examined the effects of Lycium chinense fruit on learning and memory in Morris water maze task and the choline acetyltransferase (ChAT) and cyclic adenosine monophosphate (cAMP) of rats with trimethyltin (TMT)-induced neuronal and cognitive impairments. The rats were randomly divided into the following groups: naïve rat (Normal), TMT injection+saline administered rat (control) and TMT injection+LCF administered rat (LCF). Rats were administered with saline or LCF (100 mg/kg, p.o.) daily for 2 weeks, followed by their training to the tasks. In the water maze test, the animals were trained to find a platform in a fixed position during 6d and then received 60s probe trial on the 7(th) day following removal of platform from the pool. Rats with TMT injection showed impaired learning and memory of the tasks and treatment with LCF (p<0.01) produced a significant improvement in escape latency to find the platform in the Morris water maze at the 2(nd) day. Consistent with behavioral data, treatment with LCF also slightly reduced the loss of ChAT and cAMP in the hippocampus compared to the control group. These results demonstrated that LCF has a protective effect against TMT-induced neuronal and cognitive impairments. The present study suggests that LCF might be useful in the treatment of TMT-induced learning and memory deficit.