183 research outputs found

    Mott-Kondo Insulator Behavior in the Iron Oxychalcogenides

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    We perform a combined experimental-theoretical study of the Fe-oxychalcogenides (FeO\emph{Ch}) series La2_{2}O2_{2}Fe2_{2}O\emph{M}2_{2} (\emph{M}=S, Se), which is the latest among the Fe-based materials with the potential \ to show unconventional high-Tc_{c} superconductivity (HTSC). A combination of incoherent Hubbard features in X-ray absorption (XAS) and resonant inelastic X-ray scattering (RIXS) spectra, as well as resitivity data, reveal that the parent FeO\emph{Ch} are correlation-driven insulators. To uncover microscopics underlying these findings, we perform local density approximation-plus-dynamical mean field theory (LDA+DMFT) calculations that unravel a Mott-Kondo insulating state. Based upon good agreement between theory and a range of data, we propose that FeO\emph{Ch} may constitute a new, ideal testing ground to explore HTSC arising from a strange metal proximate to a novel selective-Mott quantum criticality

    Coalescence of RAGE in Lipid Rafts in Response to Cytolethal Distending Toxin-Induced Inflammation

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    The receptor for advanced glycation end products (RAGE) interacts with various molecules in the cell membrane to induce an inflammatory response. The cytolethal distending toxin (CDT) produced by Campylobacter jejuni contains three subunits: CdtA, CdtB, and CdtC. Amongst, CdtA and CdtC interact with membrane lipid rafts, by which CdtB enters the nucleus to induce pathogenesis. In this study, we first explored the relationships between RAGE, lipid rafts, and inflammation in gastrointestinal epithelial cells exposed to CDT. Our results showed that CDT activated the expression of RAGE and high mobility group box 1 (HMGB1), followed by the recruitment of RAGE into lipid rafts. In contrast, RAGE antagonist inhibited CDT-induced inflammation via the RAGE-HMGB1 axis. Disruption of lipid rafts decreased CDT-induced downstream signaling, which in turn attenuated the inflammatory response. Furthermore, in vivo studies revealed severe inflammation and upregulation of RAGE and IL-1β in the intestinal tissues of CDT-treated mice. These results demonstrate that mobilization of RAGE to lipid rafts plays a crucial role in CDT-induced inflammation

    Retrospective comparison between a regular and a split-dose protocol of 5-fluorouracil, cisplatin, and mitoxantrone for the treatment of far advanced hepatocellular carcinoma

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    <p>Abstract</p> <p>Background</p> <p>In patients with advanced hepatocellular carcinoma (HCC), combination chemotherapy using 5- fluorouracil, cisplatin, and mitoxantrone (FMP) could achieve a response rate > 20%, but the beneficial effect was compromised by formidable adverse events. Chemotherapy given in a split-dose manner was associated with reduced toxicities. In this retrospective study, we compared the efficacies and side effects between a regular and a split-dose FMP protocol approved in our medical center.</p> <p>Methods</p> <p>From 2005 to 2008, the clinical data of 84 patients with far advanced HCC, who had either main portal vein thrombosis and/or extrahepatic metastasis, were reviewed. Of them, 65 were treated by either regular (n = 27) or split-dose (n = 38) FMP and had completed at least one therapeutic course. The remaining 19 patients were untreated. Clinical parameters, therapeutic responses, survivals and adverse events were compared.</p> <p>Results</p> <p>The median overall survival was 6.0, 5.2, and 1.5 months, respectively, in patients receiving regular FMP, split-dose FMP, and no treatment (regular versus split-dose group, P = 0.447; regular or split-dose versus untreated group; P < 0.0001). Patients receiving split-dose treatment had a significantly lower risk of grade 3/4 neutropenia (51.9 versus 10.5%, P = 0.0005). When the two treated groups were combined, the median overall survival was 10.6 and 3.8 months respectively for patients achieving disease control and progressive disease (P < 0.001). Cox proportion hazard model identified Child-Pugh stage B (hazard ratio [HR], 2.216; P = 0.006), presence of extrahepatic metastasis (HR, 0.574; P = 0.048), and achievement of disease control (HR, 0.228; P < 0.001) as independent factors associated with overall survival. Logistic regression analysis revealed that anti-hepatitis C virus antibody (odds ratio [OR], 9.219; P = 0.002) tumor size (OR, 0.816; P = 0.036), and previous anti-cancer therapy (OR, 0.195; P = 0.017) were significantly associated with successful disease control.</p> <p>Conclusions</p> <p>Comparable overall survival was observed between patients receiving regular and split-dose FMP therapies. Patients receiving split-dose therapy had a significantly lower risk of grade 3/4 neutropenia. Positive anti-hepatitis C virus antibody, smaller tumor size, and absence of previous anti-cancer therapy were independent predictors for successful disease control.</p

    Efficient Hydrogen Production from Methanol Using a Single-Site Pt1/CeO2 Catalyst.

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    Hydrogen is regarded as an attractive alternative energy carrier due to its high gravimetric energy density and only water production upon combustion. However, due to its low volumetric energy density, there are still some challenges in practical hydrogen storage and transportation. In the past decade, using chemical bonds of liquid organic molecules as hydrogen carriers to generate hydrogen in situ provided a feasible method to potentially solve this problem. Research efforts on liquid organic hydrogen carriers (LOHCs) seek practical carrier systems and advanced catalytic materials that have the potential to reduce costs, increase reaction rate, and provide a more efficient catalytic hydrogen generation/storage process. In this work, we used methanol as a hydrogen carrier to release hydrogen in situ with the single-site Pt1/CeO2 catalyst. Moreover, in this reaction, compared with traditional nanoparticle catalysts, the single site catalyst displays excellent hydrogen generation efficiency, 40 times higher than 2.5 nm Pt/CeO2 sample, and 800 times higher compared to 7.0 nm Pt/CeO2 sample. This in-depth study highlights the benefits of single-site catalysts and paves the way for further rational design of highly efficient catalysts for sustainable energy storage applications

    Blockchain as a CA: A Provably Secure Signcryption Scheme Leveraging Blockchains

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    Although encryption and signatures have been two fundamental technologies for cryptosystems, they still receive considerable attention in academia due to the focus on reducing computational costs and communication overhead. In the past decade, applying certificateless signcryption schemes to solve the higher cost of maintaining the certificate chain issued by a certificate authority (CA) has been studied. With the recent increase in the interest in blockchains, signcryption is being revisited as a new possibility. The concepts of a blockchain as a CA and a transaction as a certificate proposed in this paper aim to use a blockchain without CAs or a trusted third party (TTP). The proposed provably secure signcryption scheme implements a designated recipient beforehand such that a sender can cryptographically facilitate the interoperation on the blockchain information with the designated recipient. Thus, the proposed scheme benefits from the following advantages: (1) it removes the high maintenance cost from involving CAs or a TTP, (2) it seamlessly integrates with blockchains, and (3) it provides confidential transactions. This paper also presents the theoretical security analysis and assesses the performance via the simulation results. Upon evaluating the operational cost in real currency based on Ethereum, the experimental results demonstrate that the proposed scheme only requires a small cost as a fee

    The Impact of Emotional Symptoms and Family Support on the Association Between Homophobic Bullying and Sedative/Hypnotic Use among Gay and Bisexual Men in Taiwan: A Moderated Mediation Model

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    Sedative/hypnotic use and homophobic bullying have become a big mental health concern for gay and bisexual men. However, few studies have investigated the mediators and moderators of the association between them. The current study aimed to build a conceptual model to estimate the mediating effect of emotional symptoms and the moderating effect of family support on this association among gay and bisexual men in Taiwan. A total of 500 gay or bisexual men were recruited for the study. Their history of homophobic bullying, their experience of sedative/hypnotic use, their perceived family support, and their current emotional symptoms were evaluated using self-reporting questionnaires. A moderated mediation model was developed to test the mediating effect of emotional symptoms and the moderating effect of family support. A higher level of homophobic bullying was significantly associated with sedative/hypnotic use among gay and bisexual men and this was mediated by a higher severity of emotional symptoms. A moderating effect of family support was identified, wherein the mediating effect of emotional symptoms was weaker when there was a higher level of perceived family support, thus revealing the protective effect of family support. The significant impact of emotional symptoms and family support on the association between homophobic bullying and sedative/hypnotic use was identified. Timely interventions for emotional symptoms and the enhancement of family support are crucial for gay and bisexual men

    Mediating Effects of Emotional Symptoms on the Association between Homophobic Bullying Victimization and Problematic Internet/Smartphone Use among Gay and Bisexual Men in Taiwan

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    Problematic internet/smartphone use (PI/SU) and homophobic bullying has become a new type of mental health problem among sexual minorities. However, few studies have investigated the mediators of the association between these factors. We aimed to develop a model to estimate the mediating effect of emotional symptoms, including depression and anxiety, on this association among gay and bisexual men in Taiwan. In total, 500 gay or bisexual men in early adulthood were recruited, and their histories of homophobic bullying victimization during childhood and adolescence, current severity of PI/SU, and current emotional symptoms were evaluated using self-administered questionnaires. A mediation model was developed to test the mediating effect of emotional symptoms on the association between homophobic bullying victimization and PI/SU. In total, 190 (38%) and 201 (40.2%) of the participants had experiences of traditional and cyber homophobic bullying victimization, respectively. A higher level of homophobic bullying victimization was significantly associated with a more severe level of PI/SU, and this was mediated by a higher severity of emotional symptoms. There was a significant effect of emotional symptoms on the association between homophobic bullying victimization and PI/SU. Timely interventions for emotional symptoms are necessary for gay and bisexual men, especially for those who are victims of homophobic bullying
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