173 research outputs found

    PS-TRUST: Provably Secure Solution for Truthful Double Spectrum Auctions

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    Truthful spectrum auctions have been extensively studied in recent years. Truthfulness makes bidders bid their true valuations, simplifying greatly the analysis of auctions. However, revealing one's true valuation causes severe privacy disclosure to the auctioneer and other bidders. To make things worse, previous work on secure spectrum auctions does not provide adequate security. In this paper, based on TRUST, we propose PS-TRUST, a provably secure solution for truthful double spectrum auctions. Besides maintaining the properties of truthfulness and special spectrum reuse of TRUST, PS-TRUST achieves provable security against semi-honest adversaries in the sense of cryptography. Specifically, PS-TRUST reveals nothing about the bids to anyone in the auction, except the auction result. To the best of our knowledge, PS-TRUST is the first provably secure solution for spectrum auctions. Furthermore, experimental results show that the computation and communication overhead of PS-TRUST is modest, and its practical applications are feasible.Comment: 9 pages, 4 figures, submitted to Infocom 201

    Palladium-Catalyzed Site-Selective Fluorination of Unactivated C(sp3)−H Bonds

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    The transition-metal-catalyzed direct C–H bond fluorination is an attractive synthetic tool toward the preparation of organofluorines. While many methods exist for the direct sp3 C–H functionalization, site-selective fluorination of unactivated sp3 carbons remains a challenge. Direct, highly site-selective and diastereoselective fluorination of aliphatic amides via a palladium-catalyzed bidentate ligand-directed C–H bond functionalization process on unactivated sp3 carbons is reported. With this approach, a wide variety of β-fluorinated amino acid derivatives and aliphatic amides, important motifs in medicinal and agricultural chemistry, were prepared with palladium acetate as the catalyst and Selectfluor as the fluorine source

    Palladium-Catalyzed Decarboxylative Alkoxycarbonylation of Potassium Aryltrifluoroborates with Potassium Oxalate Monoesters

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    Palladium-catalyzed decarboxylative alkoxycarbonylation of potassium aryltrifluoroborates with potassium oxalate monoesters in the presence of potassium persulfate was performed under mild conditions. A number of benzoyl esters with a wide variety of substituents at different positions were efficiently synthesized with this method. Mechanism of the palladium-catalyzed decarboxylative carbonylation of aryltrifluoroborates was studied, and a radical-mediated Pd(II)/Pd(IV) catalytic cycle was proposed

    Mechanism of the slow-moving landslides in Jurassic red-strata in the Three Gorges Reservoir, China

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    Landslides in Jurassic red-strata make up a great part of geohazards in the Three Gorges Reservoir (TGR) in China. Most of them begin to move slowly with the accumulated displacement increasing stepwise, which corresponds to seasonal rainfall and 30 m of reservoir water level fluctuation (145 m to 175 m on elevation). We analyzed the movement of 21 slow moving landslides in the Jurassic red-strata in TGR, and found that all these landslides involved two differing processes; one is the sliding process with different shear speeds of soils within the sliding zone (landslide activity), and the other one is in steady state with different durations (dormant state). This means that the soil within the sliding surface may experience shearing at different shear rates and recovery in shear strength during the dormant period. To clarify the mechanism of this kind of movement, we took soil samples from the sliding surface of Xiangshanlu landslide, which occurred on August 30, 2008 in the Jurassic red-strata in TGR, and examined the shear rate dependency and recovery of shear resistance by means of ring shear tests. The results of tests at different shear rates show that the shear strength is positively dependent on the shear rate, and can be recovered within a short consolidation duration after the shearing ceased. By increasing the pore-water pressure (PWP) from the upper layer of the sample, we also examined the initiation of shearing which can simulate the restart of landsliding due to the fluctuation of groundwater level caused by rainfall or changes in reservoir water level. The monitored PWP near the sliding surface revealed that there was a delayed response of PWP near the sliding surface to the applied one. This kind of delayed response in pore-water pressure may provide help for the prediction of landslide occurrence due to rainfall or fluctuation of reservoir water level

    Determination of the peptide AWRK6 in rat plasma by liquid chromatography-tandem mass spectrometry (LC-MS/MS) and its application to pharmacokinetics

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    AWRK6 was a synthesized peptide developed based on the natural occurring peptide dybowskin-2CDYa, which was discovered in frog skin in our previous study. Here, a quantitative determination method for AWRK6 analysis in rat plasma by using liquid chromatography-tandem mass spectrometry (LC-MS/MS) was established and validated following U.S. FDA guidelines. A combination of plasma precipitation and liquid−liquid extraction was applied for the extraction. For pharmacokinetics study, the rats were administrated with AWRK6 via intraperitoneal and intravenous injection. The prepared plasma samples were separated on an ODS column and analyzed by tandem MS using precursor-to-product ion pairs of m/z: 533.4→84.2 for AWRK6 and m/z: 401.9→101.1 for internal standard Polymyxin B sulfate in multiple reaction monitoring mode. AWRK6 concentrations in rat plasma peaked at about 1.2 h after intraperitoneal injections at 2.35, 4.7 and 9.4 mg/kg bodyweight. The terminal half-life was around 2.8 h. The absolute bioavailability of AWRK6 was 50% after 3 doses via injection, and the apparent volume of distribution was 4.884 ± 1.736 L. The obtained determination method and pharmacokinetics profiles of AWRK6 provides a basis for further development, and forms a benchmark reference for peptide quantification

    Rescue of HLH with T and B Lymphocyte Involvement Due to Epstein-Barr Virus by PD-1 Inhibitor/Ruxolitinib and Rituximab Combination Regimens: A Case Report

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    Hemophagocytic lymphohistiocytosis (HLH) is a fatal clinical syndrome. The most common cause of secondary HLH is Epstein-Barr virus (EBV) infection. EBV-HLH is a common clinical disease with high mortality, easy relapse, and poor prognosis. Therefore, treating EBV-HLH with T and B lymphocyte involvement is challenging, and selecting an appropriate treatment regimen is critical. Moreover, research on how to evaluate the recurrence index after remission is scarce. In this study, we reported a case of EBV-HLH successfully treated with programmed cell death protein-1 (PD-1) inhibitor in combination with rituximab. The regimen had a good curative effect, and we successfully detected the trend of early recurrence. Our findings indicated that PD-1 inhibitor in combination with rituximab may help to treat EBV-HLH and maintain EBV-infected T and B whole-line lymphocytes

    Aroma Quality Evaluation of High-Quality and Quality-Deficient Black Tea by Electronic Nose Coupled with Gas Chromatography-Mass Spectrometry

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    According to the results of sensory evaluation performed by experts, 14 black tea samples were divided into two groups based on their aroma quality: high-quality and quality-deficient black tea. Using fast gas chromatography-electronic-nose (GC-E-Nose) and gas chromatography-mass spectrometry (GC-MS) combined with multivariate statistical analysis, discriminant analysis of the two groups were carried out, and the key differential components between these groups were selected. The results showed that 117-dimensional dataset was obtained by the fusion of the GC-E-Nose (44-dimensional) and GC-MS (73-dimensional) data and used to establish a model for accurate classification of the two types of black tea employing orthogonal partial least squares-discriminant analysis (OPLS-DA). The model’s explanatory and predictive capacity (R2Y = 0.976, Q2 = 0.959) were better than those of the model established based on the GC-E-Nose or GC-MS data. Based on variable important in projection (VIP) scores > 1.6 and P < 0.05, eight key aroma components including dimethyl sulfide (B3 and B25), β-ionone (A59), (3E)-4,8-dimethylnon-1,3,7-triene (A20), dihydroactinidiolide (A64), linalool (A17), phenylethyl alcohol (A19), δ-octyl lactone (A41) and γ-nonalatone (A45) were selected, which played an important role in the classification. These results showed that GC-E-Nose combined with GC-MS allows rapid and accurate discrimination between quality-deficient and high-quality black tea, which can be used as a supplement to traditional sensory evaluation, providing technical support for quality control and improvement of black tea
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