1,945 research outputs found

    Transient Global Amnesia After Ablation of the Left Lateral Accessory Pathway

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    Transient global amnesia (TGA) could be encountered in many situations even during invasive procedures. In ablation therapy for arrhythmia, there was only one reported case in the ablation of premature ventricular beats. We report a 31-year-old man having paroxysmal supraventricular tachycardia who underwent TGA at the end of ablation and recovered quickly after 8-9 hours later. Long-term follow-up showed no neurologic deficits for 8 months

    Studies towards the Total Asymmetric Synthesis of the Pentacyclic Indole Alkaloid Arboflorine: Asymmetric Synthesis of a Key Intermediate

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    The synthesis of a plausible key intermediate for a biomimetic asymmetric synthesis of indole alkaloid arboflorine is described. The method featured the use of Ellman's sulfinamide chemistry for the establishment of the first chiral center, and the Polonovski-Potier reaction for the formation of the alpha-aminonitrile moiety.NSF of China[20832005]; NFFTBS[J1030415]; National Basic Research Program (973 Program) of China[2010CB833200

    When Social Influence Meets Item Inference

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    Research issues and data mining techniques for product recommendation and viral marketing have been widely studied. Existing works on seed selection in social networks do not take into account the effect of product recommendations in e-commerce stores. In this paper, we investigate the seed selection problem for viral marketing that considers both effects of social influence and item inference (for product recommendation). We develop a new model, Social Item Graph (SIG), that captures both effects in form of hyperedges. Accordingly, we formulate a seed selection problem, called Social Item Maximization Problem (SIMP), and prove the hardness of SIMP. We design an efficient algorithm with performance guarantee, called Hyperedge-Aware Greedy (HAG), for SIMP and develop a new index structure, called SIG-index, to accelerate the computation of diffusion process in HAG. Moreover, to construct realistic SIG models for SIMP, we develop a statistical inference based framework to learn the weights of hyperedges from data. Finally, we perform a comprehensive evaluation on our proposals with various baselines. Experimental result validates our ideas and demonstrates the effectiveness and efficiency of the proposed model and algorithms over baselines.Comment: 12 page

    Oxygen dissociation on the C3N monolayer: A first-principles study

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    The oxygen dissociation and the oxidized structure on the pristine C3N monolayer in exposure to air are the inevitably critical issues for the C3N engineering and surface functionalization yet have not been revealed in detail. Using the first-principles calculations, we have systematically investigated the possible O2 adsorption sites, various O2 dissociation pathways and the oxidized structures. It is demonstrated that the pristine C3N monolayer shows more O2 physisorption sites and exhibits stronger O2 adsorption than the pristine graphene. Among various dissociation pathways, the most preferable one is a two-step process involving an intermediate state with the chemisorbed O2 and the barrier is lower than that on the pristine graphene, indicating that the pristine C3N monolayer is more susceptible to oxidation than the pristine graphene. Furthermore, we found that the most stable oxidized structure is not produced by the most preferable dissociation pathway but generated from a direct dissociation process. These results can be generalized into a wide range of temperatures and pressures using ab initio atomistic thermodynamics. Our findings deepen the understanding of the chemical stability of 2D crystalline carbon nitrides under ambient conditions, and could provide insights into the tailoring of the surface chemical structures via doping and oxidation.Comment: 23 pages,8 figure

    Effects of cadmium exposure on tissue structure, antioxidant enzyme activity, serum biochemical indices and gene expression in the liver of juvenile largemouth bass (<em>Micropterus salmoides</em>)

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    This study aimed to understand the effect of various levels of waterborne cadmium exposure and associated integrated response in largemouth bass (Micropterus salmoides). The experimental fish were randomly divided into 4 groups: Group H (high concentration group): 0.25 mg/L of water (100% of the LC~50~); Group M (medium concentration group): 0.01 mg/L of water (50% of the LC~50~); group L (low concentration group): 0.05 mg/L of water (12.5% of the LC~50~) and group C (control). Experimental fish in group C (control group) were cultured in cadmium (Cd)-free tap water. After 28 days of Cd exposure, the gill and liver tissues were collected for histological analysis and antioxidant enzyme activities assay. Serum biochemical indices and the expression levels of HSP70, HSP90, Cyp1a, and MT in the liver were assayed. Results indicated Cd exposure in group H could significantly damage the gill and liver. The SOD activity of gill and liver exhibited an increasing trend with Cd concentrations increasing, and SOD activities increased significantly in group M compared to that of group C. Still, SOD activity significantly decreased in group H. MDA content increased significantly in both the gill and liver, while T-AOC activities were not significantly different in both the gill and liver. By comparison with group C, the activities of ALT and AST in serum were significantly increased in group M and group H; the contents of ALB and TP significantly decreased in group M and group H except for the content slightly increased in the group L; the contents of GLU, TG, and TC did not show significant changes in the group L and the group M, but increased significantly in the group H. The expression levels of HSP70 and HSP90 in the liver exhibited the highest level in group M, whereas the expression levels of MT and Cyp1a were highest in groups H and L, respectively. Our results are intended to provide a reference basis for the safety risk evaluation of Cd and healthy fish farming

    Versatile and chemoselective transformation of aliphatic and aromatic secondary amides to nitriles

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    通讯作者地址: Huang, PQTriflic anhydride in combination with 2-fluoropyridine effectively dehydrates secondary amides to afford nitriles under mild reaction conditions. The reaction is general in scope and compatible with the use of aliphatic, alpha,beta-unsaturated, aromatic, and heteroaromatic amides bearing either secondary, tertiary, or benzylic N-alkyl groups. The reaction also shows good to excellent chemoselectivity for the secondary amide and tolerates several labile functional groups.Natural Science Foundation of China (NSFC) 21332007 Program for Changjiang Scholars and Innovative Research Team in University of the Ministry of Education of Chin

    Clinicopathologic Evaluation of Prognostic Factors for Squamous Cell Carcinoma of the Buccal Mucosa

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    BackgroundThe purpose of this research was to evaluate the prognostic significance of clinicopathologic variables on the survival rate for squamous cell carcinoma of the buccal mucosa (BMSCC). We analyzed the outcomes of surgical therapy for this aggressive cancer and compared these results with those in the literature.MethodsWe reviewed the medical charts of 172 patients treated in our institution between 1990 and 2005. There were 22 patients excluded from our studies: 20 patients with advanced tumors who received no treatment or palliative treatment, and 2 patients who had received preoperative radiotherapy (RT). The remaining 150 patients were treated with surgeries and among them, 56 patients had undergone postoperative RT. The influence of clinicopathologic factors on the survival rate was analyzed with the Kaplan-Meier method and log-rank test. Multivariate analysis was assessed with Cox's regression model.ResultsThere were 148 males and 2 females, with a mean age of 53.5 years. The prevalence rate of habitual betel quid chewing documented in charts among 113 patients was 75%. The 5-year overall survival rate and disease-specific survival rate for all patients were 64% and 69%, respectively. For patients with stages I, II, III, and IV disease, the 5-year disease-specific survival rates were 90%, 77%, 52%, and 47%, respectively (p< 0.001). According to the multivariate analysis, the pathologic staging and histologic grading of the tumor were independently the important prognostic factors affecting survival rate. There were 80 patients who developed locoregional recurrence in lymph nodes in the follow-up diagnoses. Distant metastases occurred in 14 patients, with 11 of them also having locoregional recurrence. The distant metastases were found in the lungs (8/14), T-spine (3/14), liver (2/14) and brain (1/14).ConclusionPathologic stage and histologic grade are the most important prognostic factors
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