1,847 research outputs found

    Interplay between Quantum Size Effect and Strain Effect on Growth of Nanoscale Metal Thin Film

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    We develop a theoretical framework to investigate the interplay between quantum size effect (QSE) and strain effect on the stability of metal nanofilms. The QSE and strain effect are shown to be coupled through the concept of "quantum electronic stress. First-principles calculations reveal large quantum oscillations in the surface stress of metal nanofilms as a function of film thickness. This adds extrinsically additional strain-coupled quantum oscillations to surface energy of strained metal nanofilms. Our theory enables a quantitative estimation of the amount of strain in experimental samples, and suggests strain be an important factor contributing to the discrepancies between the existing theories and experiments

    Layer-refined Graph Convolutional Networks for Recommendation

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    Recommendation models utilizing Graph Convolutional Networks (GCNs) have achieved state-of-the-art performance, as they can integrate both the node information and the topological structure of the user-item interaction graph. However, these GCN-based recommendation models not only suffer from over-smoothing when stacking too many layers but also bear performance degeneration resulting from the existence of noise in user-item interactions. In this paper, we first identify a recommendation dilemma of over-smoothing and solution collapsing in current GCN-based models. Specifically, these models usually aggregate all layer embeddings for node updating and achieve their best recommendation performance within a few layers because of over-smoothing. Conversely, if we place learnable weights on layer embeddings for node updating, the weight space will always collapse to a fixed point, at which the weighting of the ego layer almost holds all. We propose a layer-refined GCN model, dubbed LayerGCN, that refines layer representations during information propagation and node updating of GCN. Moreover, previous GCN-based recommendation models aggregate all incoming information from neighbors without distinguishing the noise nodes, which deteriorates the recommendation performance. Our model further prunes the edges of the user-item interaction graph following a degree-sensitive probability instead of the uniform distribution. Experimental results show that the proposed model outperforms the state-of-the-art models significantly on four public datasets with fast training convergence. The implementation code of the proposed method is available at https://github.com/enoche/ImRec.Comment: 12 pages, 5 figure

    Comparison of Pulmonary Function Changes Between Patients Receiving Neoadjuvant Chemotherapy and Chemoradiotherapy Prior to Minimally Invasive Esophagectomy: A Randomized and Controlled Trial

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    PURPOSE: Adequate pulmonary function is important for patients undergoing surgical resection of esophageal cancer, especially those that received neoadjuvant therapy. However, it is unknown if pre-operative radiation affects pulmonary function differently compared to chemotherapy. The purpose of this study was to compare changes in pulmonary function between patients undergoing minimally invasive esophagectomy (MIE) who received neoadjuvant chemotherapy or chemoradiotherapy. METHODS: Between March 2017 and March 2018, esophageal cancer patients requiring neoadjuvant therapy were prospectively enrolled and randomly assigned to receive chemotherapy (CT) or chemoradiotherapy (CRT) before MIE. All patients received pulmonary function testing before and after the neoadjuvant therapy. Changes in pulmonary function, operative data, and pulmonary complications were compared between the 2 groups. RESULTS: A total of 71 patients were randomized and underwent MIE after receiving CT (n = 34) or CRT (n = 37). Baseline clinical characteristics were comparable between the 2 groups. The CRT group experienced a greater decrease of forced expiratory volume at 1 s (FEV CONCLUSIONS: Preoperative CRT affects pulmonary function more than CT alone, but does not increase the risk of pulmonary complications in patients undergoing MIE

    Association between genetic polymorphisms of CYP2A13, CYP2A6 and risk of nasopharyngeal carcinoma in southern Chinese population

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    Abstract: Background: Cytochrome P450 2A13 (CYP2A13) and 2A6 (CYP2A6) are enzymes expressed in the human respiratory tract, exhibit high efficiency in the metabolic activation of tobacco carcinogen 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK). A C→T transition in the CYP2A13 gene causes Arg257Cys amino acid substitution and a deletion of the CYP2A6 gene named as CYP2A6 *4, both of them result in a significantly reduced activity toward NNK and other substrates. In this case-control study, we investigated the association between the CYP2A13 and CYP2A6 variants, smoking status and the risk of developing nasopharyngeal carcinoma (NPC) in the Cantonese population living in southern China. Materials and Methods: Genotypes of CYP2A13 and CYP2A6 genes were analyzed by using polymerase chain reaction-based restriction fragment length polymorphism (PCR-RFLP) assays and two-step PCR method. Results: Neither the CYP2A13 -3375T variants nor CYP2A6 *4 variants were associated with risk of NPC (OR = 0.84, 95% CI = 0.59-1.20, and OR = 0.83, 95% CI = 0.58-1.18, respectively) compared with their wild genotypes. Combination analysis showed that individuals with both CYP2A13 CT or TT variants and CYP2A6 *4 variants had no association with risk for NPC (OR = 0.71, 95% CI = 0.33-1.52) compared with those with both CYP2A13 CC and CYP2A6 *1/*1 genotypes. No association with the risk of NPC was observed in smokers with CYP2A13 C/T polymorphisms or smokers with CYP2A6 *4 variant polymorphisms (OR = 0.75, 95% CI = 0.43-1.32, and OR = 0.90, 95% CI = 0.27-1.70; respectively), including after stratification of smoking status. Furthermore, we did not observe association between the combination of two gene polymorphisms and smokers and risk of developing NPC, including the stratification of smoking. Discussions: Based on the results of this study, the effect of these two CYP2A13 and CYP2A6 enzymes may be not so important in developing of NPC as in other cancers, such as lung cancer. ). http://www.cancer-biology.org

    Polymorphisms and a Haplotype in Heparanase Gene Associations with the Progression and Prognosis of Gastric Cancer in a Northern Chinese Population

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    Background: Human heparanase plays an important role in cancer development and single nucleotide polymorphisms (SNPs) in the heparanase gene (HPSE) have been shown to be correlated with gastric cancer. The present study examined the associations between individual SNPs or haplotypes in HPSE and susceptibility, clinicopathological parameters and prognosis of gastric cancer in a large sample of the Han population in northern China. Methodology/Principal Findings: Genomic DNA was extracted from formalin-fixed, paraffin-embedded normal gastric tissue samples from 404 patients and from blood from 404 healthy controls. Six SNPs were genotyped by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. A chi-square (x2) test and unconditional logistic regression were used to analyze the risk of gastric cancer; a Log-rank test and Cox proportional hazards model were used to produce survival analysis and a Kaplan-Meier method was used to map survival curves. The mean genotyping success rates were more than 99 % in both groups. Haplotype CA in the block composed of rs11099592 and rs4693608 had a greater distribution in the group of Borrmann types 3 and 4 (P = 0.037), the group of a greater number of lymph node metastases (N3 vs N0 group, P = 0.046), and moreover was correlated to poor survival (CG vs CA: HR = 0.645, 95%CI: 0.421–0.989, P = 0.044). In addition, genotypes rs4693608 AA and rs4364254 TT were associated with poor survival (P = 0.030, HR = 1.527, 95%CI: 1.042–2.238 for rs4693608 AA; P = 0.013, HR = 1.546, 95%CI: 1.096–2.181 for rs4364254 TT). There were n

    One-Pot Synthesis of Renewable Phthalic Anhydride from 5-Hydroxymethfurfural by using MoO3 /Cu(NO3 )2 as Catalyst.

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    Herein, a synthetic pathway to renewable phthalic anhydride (PA) from 5-hydroxymethfurfural (HMF) in one pot is reported. The commonly available catalysts MoO3 and Cu(NO3 )2 play a crucial role in integrating the multiple steps of the reaction, namely decarbonylation of HMF to active furyl intermediate (AFI), oxidation of HMF to maleic anhydride (MA), Diels-Alder cycloaddition of AFI and MA, and subsequent dehydration, in one pot. Under mild reaction conditions, a 63.2 % yield of PA is obtained from HMF. Compared with the currently reported route to renewable PA based on the Diels-Alder cycloaddition of biomass-derived MA and furan, this convenient one-pot synthesis represents a great improvement in efficiency

    Duration of viral shedding of Influenza A (H1N1) virus infection treated with oseltamivir and/or Traditional Chinese Medicine in China: A retrospective analysis

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    AbstractObjectiveH1N1 was a new and potentially serious infectious disease, in human, the severity of influenza can vary from mild to severe, thus to find an effective and safety way to control the influenza pandemic is of crucial importance. This retrospective study describes the duration of viral shedding in H1N1 patients that were hospitalized and treated in China.MethodsClinical data were collected from May to July, 2009 in China for 963 patients with influenza A (H1N1) virus infection. Patients were treated based on the guidelines issued by the Chinese Ministry of Health. The primary outcome was duration of viral shedding and statistical comparisons were performed.ResultsIn the patients with body temperature greater than 38.0°C, there were no differences in virus shedding duration among the patients taking oseltamivir within two days, patients undergoing Traditional Chinese Medicine (TCM) therapy or those receiving no drug therapy. In patients with body temperature ≥38.1°C, TCM therapy reduced the viral shedding duration (P<0.05, vs. oseltamivir therapy). Furthermore, taking oseltamivir two days after onset of symptoms might prolong the virus shedding duration (P<0.05, vs. taking oseltamivir less than 2 days of onset).ConclusionTCM therapy is effective for reducing the length of virus shedding in patients with body temperature ≥38.0°C. Oseltamivir used for reducing virus shedding duration should be taken within two days of onset

    ISPTM: an Iterative Search Algorithm for Systematic Identification of Post-translational Modifications from Complex Proteome Mixtures

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    Identifying protein post-translational modifications (PTMs) from tandem mass spectrometry data of complex proteome mixtures is a highly challenging task. Here we present a new strategy, named iterative search for identifying PTMs (ISPTM), for tackling this challenge. The ISPTM approach consists of a basic search with no variable modification, followed by iterative searches of many PTMs using a small number of them (usually two) in each search. The performance of the ISPTM approach was evaluated on mixtures of 70 synthetic peptides with known modifications, on an 18-protein standard mixture with unknown modifications and on real, complex biological samples of mouse nuclear matrix proteins with unknown modifications. ISPTM revealed that many chemical PTMs were introduced by urea and iodoacetamide during sample preparation and many biological PTMs, including dimethylation of arginine and lysine, were significantly activated by Adriamycin treatment in NM associated proteins. ISPTM increased the MS/MS spectral identification rate substantially, displayed significantly better sensitivity for systematic PTM identification than the conventional all-in-one search approach and offered PTM identification results that were complementary to InsPecT and MODa, both of which are established PTM identification algorithms. In summary, ISPTM is a new and powerful tool for unbiased identification of many different PTMs with high confidence from complex proteome mixtures

    Three Bianthraquinone Derivatives from the Mangrove Endophytic Fungus Alternaria sp. ZJ9-6B from the South China Sea

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    Three new bianthraquinone derivatives, alterporriol K (1), L (2) and M (3), along with six known compounds were obtained from extracts of the endophytic fungus Alternaria sp. ZJ9-6B, isolated from the mangrove Aegiceras corniculatum collected in the South China Sea. Their structures were elucidated by one- and two-dimensional NMR spectroscopy, MS data analysis and circular dichroism measurements. Compounds 1, 2 and 3 were first isolated alterporriols with a C-2–C-2′ linkage. The crystallographic data of tetrahydroaltersolanol B (7) was reported for the first time. In the primary bioassays, alterporriol K and L exhibited moderate cytotoxic activity towards MDA-MB-435 and MCF-7 cells with IC50 values ranging from 13.1 to 29.1 μM
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