1,331 research outputs found

    An evolutionary dynamic multi-objective optimization algorithm based on center-point prediction and sub-population autonomous guidance

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    Dynamic multi-objective optimization problems (DMOPs) provide a challenge in that objectives conflict each other and change over time. In this paper, a hybrid approach based on prediction and autonomous guidance is proposed, which responds the environmental changes by generating a new population. According to the position of historical population, a part of the population is generated by predicting roughly and quickly. In addition, another part of the population is generated by autonomous guidance. A sub-population from current population evolves several generations independently, which guides the current population into the promising area. Compared with other three algorithms on a series of benchmark problems, the proposed algorithm is competitive in convergence and diversity. Empirical results indicate its superiority in dealing with dynamic environments

    A Dispersive Analysis on the f0(600)f_0(600) and f0(980)f_0(980) Resonances in γγπ+π,π0π0\gamma\gamma\to\pi^+\pi^-, \pi^0\pi^0 Processes

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    We estimate the di-photon coupling of f0(600)f_0(600), f0(980)f_0(980) and f2(1270)f_2(1270) resonances in a coupled channel dispersive approach. The f0(600)f_0(600) di-photon coupling is also reinvestigated using a single channel TT matrix for ππ\pi\pi scattering with better analyticity property, and it is found to be significantly smaller than that of a qˉq\bar qq state. Especially we also estimate the di-photon coupling of the third sheet pole located near KˉK\bar KK threshold, denoted as f0III(980)f_0^{III}(980). It is argued that this third sheet pole may be originated from a coupled channel Breit-Wigner description of the f0(980)f_0(980) resonance.Comment: 24 pages and 13 eps figures. A nuerical bug in previous version is fixed. Some results changed. References and new figures added. Version to appear in Phys. Rev.

    Spheres and Prolate and Oblate Ellipsoids from an Analytical Solution of Spontaneous Curvature Fluid Membrane Model

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    An analytic solution for Helfrich spontaneous curvature membrane model (H. Naito, M.Okuda and Ou-Yang Zhong-Can, Phys. Rev. E {\bf 48}, 2304 (1993); {\bf 54}, 2816 (1996)), which has a conspicuous feature of representing the circular biconcave shape, is studied. Results show that the solution in fact describes a family of shapes, which can be classified as: i) the flat plane (trivial case), ii) the sphere, iii) the prolate ellipsoid, iv) the capped cylinder, v) the oblate ellipsoid, vi) the circular biconcave shape, vii) the self-intersecting inverted circular biconcave shape, and viii) the self-intersecting nodoidlike cylinder. Among the closed shapes (ii)-(vii), a circular biconcave shape is the one with the minimum of local curvature energy.Comment: 11 pages, 11 figures. Phys. Rev. E (to appear in Sept. 1999

    Targeting oncogenic miR-335 inhibits growth and invasion of malignant astrocytoma cells

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    <p>Abstract</p> <p>Background</p> <p>Astrocytomas are the most common and aggressive brain tumors characterized by their highly invasive growth. Gain of chromosome 7 with a hot spot at 7q32 appears to be the most prominent aberration in astrocytoma. Previously reports have shown that microRNA-335 (miR-335) resided on chromosome 7q32 is deregulated in many cancers; however, the biological function of miR-335 in astrocytoma has yet to be elucidated.</p> <p>Results</p> <p>We report that miR-335 acts as a tumor promoter in conferring tumorigenic features such as growth and invasion on malignant astrocytoma. The miR-335 level is highly elevated in C6 astrocytoma cells and human malignant astrocytomas. Ectopic expression of miR-335 in C6 cells dramatically enhances cell viability, colony-forming ability and invasiveness. Conversely, delivery of antagonist specific for miR-335 (antagomir-335) to C6 cells results in growth arrest, cell apoptosis, invasion repression and marked regression of astrocytoma xenografts. Further investigation reveals that miR-335 targets disheveled-associated activator of morphogenesis 1(Daam1) at posttranscriptional level. Moreover, silencing of endogenous Daam1 (siDaam1) could mimic the oncogenic effects of miR-335 and reverse the growth arrest, proapoptotic and invasion repression effects induced by antagomir-335. Notably, the oncogenic effects of miR-335 and siDAAM1 together with anti-tumor effects of antagomir-335 are also confirmed in human astrocytoma U87-MG cells.</p> <p>Conclusion</p> <p>These findings suggest an oncogenic role of miR-335 and shed new lights on the therapy of malignant astrocytomas by targeting miR-335.</p

    Credibility theory-based available transfer capability assessment

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    Since the development of large scale power grid interconnections and power markets, research on available transfer capability (ATC) has attracted great attention. The challenges for accurate assessment of ATC originate from the numerous uncertainties in electricity generation, transmission, distribution and utilization sectors. Power system uncertainties can be mainly described as two types: randomness and fuzziness. However, the traditional transmission reliability margin (TRM) approach only considers randomness. Based on credibility theory, this paper firstly built models of generators, transmission lines and loads according to their features of both randomness and fuzziness. Then a random fuzzy simulation is applied, along with a novel method proposed for ATC assessment, in which both randomness and fuzziness are considered. The bootstrap method and multi-core parallel computing technique are introduced to enhance the processing speed. By implementing simulation for the IEEE-30-bus system and a real-life system located in Northwest China, the viability of the models and the proposed method is verified

    A prediction strategy based on decision variable analysis for dynamic multi-objective optimization

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    The file attached to this record is the author's final peer reviewed version. The Publisher's final version can be found by following the DOI link.Many multi-objective optimization problems in reality are dynamic, requiring the optimization algorithm to quickly track the moving optima after the environment changes. Therefore, response strategies are often used in dynamic multi-objective algorithms to find Pareto optimal. In this paper, we propose a hybrid prediction strategy based on the classification of decision variables, which consists of three steps. After detecting the environment change, the first step is to analyze the influence of each decision variable on individual convergence and distribution in the new environment. The second step is to adopt different prediction methods for different decision variables. Finally, adaptive selection is applied to the solution set generated in the first and second steps, and solutions with good convergence and diversity are selected to make the initial population more adaptable to the new environment. The prediction strategy can help the solution set converge while maintaining its diversity. The experimental results and performance show that the proposed algorithm is capable of significantly improving the dynamic optimization performance compared with five state-of-the-art evolutionary algorithms

    Pathogens and drug resistance in active surveillance of foodborne diseases from 2017 to 2019 in Chenzhou City

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    ObjectiveTo provide a scientific basis for the prevention and control of foodborne diseases in Chenzhou, the etiological characteristics and epidemiological patterns of foodborne diseases were analyzed.MethodsThe Case information and stool and anal swab samples were collected from two sentinel hospitals in Chenzhou in 2017 and 2019. According to the methods described in “National Manual of Foodborne Disease Surveillance”, the samples were tested for pathogens, pathogen typing, and drug sensitivity.ResultsA total of 825 samples of diarrhea cases were collected, and the total detection rate of pathogens was 30.18% (249/825), including 16.24% (134/825) Salmonella, 11.76% (97/825) Norovirus, 3.52% (29/825) diarrheal Escherichia coli, 0.73% (6/825) Vibrio parahaemolyticus, and 0.12% (1/825) Shigella. Bacterial detection rates were higher in the second and third quarters than in other quarters, and viral detection rates were higher in the first and fourth quarters than in other quarters. The highest pathogen detection rate was 40.79% (31/76) in the 2-6-year-old group. Milk and dairy products, grains and their products, and fruits and their products were suspected foods. The highest detection rate in Salmonella was in Salmonella enterica subsp.(74.63%, 100/134), the highest detection rate in diarrheal Escherichia coli was in intestinal adhesion type and enterotoxin type (34.48%, 10/29), and the norovirus was mainly GII type (85.57%, 83/97). The highest resistance rate of Salmonella to tetracycline was 88.71% (110/124), and the multidrug resistance rate of Salmonella was 85.48% (106/124). The resistance rate of diarrheal Escherichia coli to ampicillin was significant (79.31%, 23/29), and the multidrug resistance rate of diarrheal Escherichia coli was 62.07% (18/29).ConclusionThe main pathogens of diarrheal cases of foodborne diseases were Salmonella and Norovirus in Chenzhou. Salmonella and diarrheal Escherichia coli are highly resistant to antibiotics. Therefore, it is necessary to conduct targeted food safety supervision, strengthen antibiotic resistance monitoring, and strictly prevent antibiotic abuse

    Genistein Exposure Interferes with Pharmacokinetics of Celecoxib in SD Male Rats by UPLC-MS/MS

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    Objective. To discuss the effects of genistein on the metabolism of celecoxib in vitro and in vivo. Method. In vitro, the effects of genistein on the metabolism of celecoxib were studied using rat and human liver microsomes. In vivo, pharmacokinetics of celecoxib was evaluated in rats with or without genistein. Fifteen Sprague-Dawley (SD) rats were randomized into three groups: celecoxib (A group), celecoxib and 50 mg/kg genistein (B group), and celecoxib and 100 mg/kg genistein (C group). Single dose of 33.3 mg/kg celecoxib was orally administered 30 min after genistein ig. At 0.5, 1, 2, 3, 4, 6, 8, 10, 12, and 24 h after celecoxib administration, 300–400 µl blood samples were collected and the concentration of celecoxib was analyzed by ultrahigh-performance liquid chromatography-tandem mass spectrometry system. Result. Genistein showed notable inhibitory effects on three microsomes. It affected pharmacokinetics of celecoxib in vivo experiments. Genistein had dramatically ability to suppress CYP2C9∗1 and ∗3. After pretreatment with genistein, AUC and Cmax of the C group were higher than B group. CLz/F of C group was lower than the B group. Conclusion. Genistein inhibits the conversion of celecoxib in vitro and in vivo. So, the dosage of celecoxib should be adjusted if it was used associated with genistein

    A Selective Small Molecule DNA2 Inhibitor for Sensitization of Human Cancer Cells to Chemotherapy

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    Cancer cells frequently up-regulate DNA replication and repair proteins such as the multifunctional DNA2 nuclease/helicase, counteracting DNA damage due to replication stress and promoting survival. Therefore, we hypothesized that blocking both DNA replication and repair by inhibiting the bifunctional DNA2 could be a potent strategy to sensitize cancer cells to stresses from radiation or chemotherapeutic agents. We show that homozygous deletion of DNA2 sensitizes cells to ionizing radiation and camptothecin (CPT). Using a virtual high throughput screen, we identify 4-hydroxy-8-nitroquinoline-3-carboxylic acid (C5) as an effective and selective inhibitor of DNA2. Mutagenesis and biochemical analysis define the C5 binding pocket at a DNA-binding motif that is shared by the nuclease and helicase activities, consistent with structural studies that suggest that DNA binding to the helicase domain is necessary for nuclease activity. C5 targets the known functions of DNA2 in vivo: C5 inhibits resection at stalled forks as well as reducing recombination. C5 is an even more potent inhibitor of restart of stalled DNA replication forks and over-resection of nascent DNA in cells defective in replication fork protection, including BRCA2 and BOD1L. C5 sensitizes cells to CPT and synergizes with PARP inhibitors
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