47 research outputs found

    Enhanced Methanol Oxidation and CO Tolerance Using CeO\u3csub\u3e2\u3c/sub\u3e-Added Eggshell Membrane-Templated Pd Network Electrocatalyst

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    Macroporous Pd and CeO2-added Pd network catalysts have been synthesized using eggshell membrane (ESM) as a template for enhanced methanol oxidation and CO tolerance. The microstructural characterization revealed a hierarchically ordered macroporous network of Pd reproducing the fibrous structure of ESM for a Pd-only catalyst, and a flower-like CeO2-decorated Pd morphological architecture for the CeO2-added Pd catalyst synthesized by a precipitation method. XRD patterns indicated Pd and CeO2 phases with good crystallinity. The cyclic voltammetry studies showed an enhanced electrocatalytic activity for methanol oxidation in acidic aqueous medium. Because of the preferential formation of Ce–CO bonds over Pd–CO bonds, the incorporation of CeO2 into Pd-based catalysts results in an increased CO tolerance, making it a robust catalyst for methanol oxidation in direct methanol fuel cells

    Synaptic Neurotransmission Depression in Ventral Tegmental Dopamine Neurons and Cannabinoid-Associated Addictive Learning

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    Drug addiction is an association of compulsive drug use with long-term associative learning/memory. Multiple forms of learning/memory are primarily subserved by activity- or experience-dependent synaptic long-term potentiation (LTP) and long-term depression (LTD). Recent studies suggest LTP expression in locally activated glutamate synapses onto dopamine neurons (local Glu-DA synapses) of the midbrain ventral tegmental area (VTA) following a single or chronic exposure to many drugs of abuse, whereas a single exposure to cannabinoid did not significantly affect synaptic plasticity at these synapses. It is unknown whether chronic exposure of cannabis (marijuana or cannabinoids), the most commonly used illicit drug worldwide, induce LTP or LTD at these synapses. More importantly, whether such alterations in VTA synaptic plasticity causatively contribute to drug addictive behavior has not previously been addressed. Here we show in rats that chronic cannabinoid exposure activates VTA cannabinoid CB1 receptors to induce transient neurotransmission depression at VTA local Glu-DA synapses through activation of NMDA receptors and subsequent endocytosis of AMPA receptor GluR2 subunits. A GluR2-derived peptide blocks cannabinoid-induced VTA synaptic depression and conditioned place preference, i.e., learning to associate drug exposure with environmental cues. These data not only provide the first evidence, to our knowledge, that NMDA receptor-dependent synaptic depression at VTA dopamine circuitry requires GluR2 endocytosis, but also suggest an essential contribution of such synaptic depression to cannabinoid-associated addictive learning, in addition to pointing to novel pharmacological strategies for the treatment of cannabis addiction

    Large expert-curated database for benchmarking document similarity detection in biomedical literature search

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    Document recommendation systems for locating relevant literature have mostly relied on methods developed a decade ago. This is largely due to the lack of a large offline gold-standard benchmark of relevant documents that cover a variety of research fields such that newly developed literature search techniques can be compared, improved and translated into practice. To overcome this bottleneck, we have established the RElevant LIterature SearcH consortium consisting of more than 1500 scientists from 84 countries, who have collectively annotated the relevance of over 180 000 PubMed-listed articles with regard to their respective seed (input) article/s. The majority of annotations were contributed by highly experienced, original authors of the seed articles. The collected data cover 76% of all unique PubMed Medical Subject Headings descriptors. No systematic biases were observed across different experience levels, research fields or time spent on annotations. More importantly, annotations of the same document pairs contributed by different scientists were highly concordant. We further show that the three representative baseline methods used to generate recommended articles for evaluation (Okapi Best Matching 25, Term Frequency-Inverse Document Frequency and PubMed Related Articles) had similar overall performances. Additionally, we found that these methods each tend to produce distinct collections of recommended articles, suggesting that a hybrid method may be required to completely capture all relevant articles. The established database server located at https://relishdb.ict.griffith.edu.au is freely available for the downloading of annotation data and the blind testing of new methods. We expect that this benchmark will be useful for stimulating the development of new powerful techniques for title and title/abstract-based search engines for relevant articles in biomedical research.Peer reviewe

    Effects of corona discharge on the surface structure, morphology and properties of multi-walled carbon nanotubes

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    Multi-walled carbon nanotubes (MWCNTs) were modified by corona discharge and then heat treated in the air. The influences of corona discharge parameters such as treatment time and processing power were investigated. The results of energy dispersive X-ray analysis (EDX) and thermogravimetric analysis (TGA) indicated the introduction of oxygen-containing functional groups onto the surface of the MWCNTs after heat treatment. The water contact angle tests showed that the hydrophobicity of the MWCNTs was decreased to some extent. The static water contact angle was reduced from 146° to 122° when the time of the corona discharge treatment reached 3 min at the processing power of 200 W. The enhanced thermomechanical and mechanical properties of epoxy nanocomposites filled with the corona discharge treated MWCNTs were observed. The modified MWCNTs conferred better properties on the composites than the pristine MWCNTs because of the improved dispersion of MWCNTs in matrix and the enhanced interfacial interaction between the treated MWCNTs and epoxy

    Surface-initiated graft polymerization on multiwalled carbon nanotubes pretreated by corona discharge at atmospheric pressure

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    Surface-initiated graft polymerization on multi-walled carbon nanotubes pretreated with a corona discharge at atmospheric pressure was explored. The mechanism of the corona-discharge-induced graft polymerization is discussed. The results indicate that MWCNTs were encapsulated by poly(glycidyl methacrylate) (PGMA), demonstrating the formation of PGMA-grafted MWCNTs (PGMA-g-MWCNTs), with a grafting ratio of about 22 wt%. The solubility of PGMA-g-MWCNTs in ethanol was dramatically improved compared to pristine MWCNTs, which could contribute to fabricating high-performance polymer/MWCNTs nanocomposites in the future. Compared with most plasma processes, which operate at low pressures, corona discharge has the merit of working at atmospheric pressure

    Thermal degradation and flammability properties of HDPE/EVA/C60 nanocomposites

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    The thermal and flameretardancy properties of high-density polyethylene (HDPE)/ethylene vinyl-acetate copolymer (EVA)/fullerene (C60) nanocomposites were investigated by thermogravimetric analysis (TGA), differential scanning calorimetry (DSC) and cone calorimetry with C60 loading varied from 0.5 to 2% by mass fraction. Dispersion of C60 in HDPE/EVA blend was characterized by transmission electron microscopy (TEM) and scanning electron microscopy (SEM). TGA and DSC results showed that the presence of C60 could remarkably enhance the thermal stability, and cone calorimeter measurements indicated that incorporating C60 could result in a significant reduction in the peak heat release rate and a much longer time to ignition of the HDPE/EVA blend. Furthermore, the larger the C60 loading level, the better the flame retardancy of HDPE/EVA/C60 nanocomposites

    Effects of pulmonary veins ligation style for the patients' stress and cardiac on lung cancer

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    Background and objective It is needed to explore the effects of operation on stress statue, myocardial damage and arrhythmia to lung cancer. This study would compare the effects of two ligation styles of pulmonary vein on lung cancer patients' stress and cardiac postoperative. Methods 54 cases were divided into two groups randomly:the pulmonary vein trunk-ligation group (trunk group, 27 cases) and the pulmonary vein branch-ligation group (branch group, 27 cases). The blood concentrations of hydrocortisone (HC), blood glucose (BG) and cardial troponin-I (cTnI) were determined at different time point. The surgical data, the quantum of pain and ECG also recorded. Results ① There were no significance difference of the operation time, blood loss during operation and drainage volume in first day after operation between two groups. ② There're no differences of the quantum of pain between two groups. ③ The HC of the two groups' ascend obviously on the end of operation and descend during postoperative. ④ The BG of the two groups' rise on the 1st day obviously, maintain high level on the 2nd day, descend on the 3rd day but still higher than that of preoperation.⑤ The BG and HC show a direct positive correlation postoperative. ⑥ The cTnIs of the trunk group ascend immediatelyafter operation, but there's no statistically significance between two groups. ⑦ The arrhythmia incidence is higher in the trunk group, but the arrhythmia incidences classified by the date after operation of the two groups' show no distinction. Conclusion ① The effects of two pulmonary vein ligation styles on postoperative stress show no significance differences.② The style of pulmonary vein trunk-ligation has a more obvious tendency to do harm to heart than that of branch-ligation. ③ The style of pulmonary vein branch-ligation may reduce the arrhythmia incidence after operation
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