302 research outputs found

    Solitons and excitations in the duality-based matrix model

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    We analyse a specific, duality-based generalization of the hermitean matrix model. The existence of two collective fields enables us to describe specific excitations of the hermitean matrix model. By using these two fields, we construct topologically non-trivial solutions (BPS solitons) of the model. We find the low-energy spectrum of quantum fluctuations around the uniform solution. Furthermore, we construct the wave functional of the ground state and obtain the corresponding Green function.Comment: 13 pages,v2: new solutions constructed, title changed accordingl

    Solitons in the Calogero model for distinguishable particles

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    We consider a large āˆ’N,- N, two-family Calogero model in the Hamiltonian, collective-field approach. The Bogomol'nyi limit appears and the corresponding solutions are given by the static-soliton configurations. Solitons from different families are localized at the same place. They behave like a paired hole and lump on the top of the uniform vacuum condensates, depending on the values of the coupling strengths. When the number of particles in the first family is much larger than that of the second family, the hole solution goes to the vortex profile already found in the one-family Calogero model.Comment: 14 pages, no figures, late

    Quantum fluctuations of the Chern-Simons theory and dynamical dimensional reduction

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    We consider a large-N Chern-Simons theory for the attractive bosonic matter (Jackiw-Pi model) in the Hamiltonian collective-field approach based on the 1/N expansion. We show that the dynamics of low-lying density excitations around the ground-state vortex configuration is equivalent to that of the Sutherland model. The relationship between the Chern-Simons coupling constant lambda and the Calogero-Sutherland statistical parameter lambda_s signalizes some sort of statistical transmutation accompanying the dimensional reduction of the initial problem.Comment: 10 pages, 2 figure

    Statistical analysis of reinforced concrete bridges in Estonia

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    This paper introduces a possible way to use a multivariate methodology, called principal component analysis, to reduce the dimensionality of condition state database of bridge elements, collected during visual inspections. Attention is paid to the condition assessment of bridges in Estonian national roads and collected data, which plays an important role in the selection of correct statistical technique and obtaining reliable results. Additionally, detailed overview of typical road bridges and examples of collected information is provided. Statistical analysis is carried out by most natural reinforced concrete bridges in Estonia and comparison is made among different typologies. The introduced multivariate technique algorithms are presented and collated in two different formulations, with contrast on unevenness in variables and taking into account the missing data. Principal components and weighing factors, which are calculated for bridges with different typology, also have differences in results and element groups where variation is retainedTU1406 ā€“ Quality Specifications for Roadway Bridges, standardiza- tion at a European level (BridgeSpec), a COST Action sup- ported by EU Framework Programme Horizon 2020info:eu-repo/semantics/publishedVersio

    Investigation of Antibacterial Activity of Cinnamyl Derivatives of Arylpiperazine

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    The derivatives of cinnamic acid and N-arylpiperazine show antibacterial activity. In this work the potential synergistic effect of cinnamyl derivatives of arylpiperazine in selected bacteria was investigated. The antibacterial activities of the derivatives were evaluated against Gram-positive bacteria: Staphylococcus aureus, Streptosporangium longisporum, Sarcina lutea, Micrococcus flavus, Clostridium sporogenes and Bacillus subtilis and Gram-negative bacteria: Escherichia coli, Pseudomonas aeruginosa, Salmonella enteritidis and Proteus vulgaris by the disc diffusion method. The minimum inhibitory concentration (MIC) against the selected bacteria was determined for all compounds that showed activity in the disc diffusion method. The majority of the investigated compounds displayed in vitro antibacterial activity. The effect of the type and structure of the substituent on the aromatic ring on the antibacterial activity is discussed. It was found that two derivatives expressed activity toward S. longisporum and P. aeruginosa that was almost as strong as that of amikacin

    Synthesis and pharmacological evaluation of N-{4-[2-(4-arylpiperazin-1-yl) ethyl] phenyl}arylamides

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    Serotonin 5HT1a receptor belongs to a class of G-protein coupled receptors. It serves as a potential target for neurological disorders such as depression, anxiety etc. It is a well-known fact that N-arylpiperazine moiety is present in compounds with pronounced 5HT1a activity. Taking into account previously published results1 novel structures of N-{4-[2-(4- arylpiperazin-1-yl)ethyl]phenyl}arylamides (Figure 1.) were designed for target synthesis. Proposed modifications include: different position of hydroxyl group in aryl amide part of molecule and addition of methoxy and chloro substituents to the phenyl ring of parent compounds, since their introduction in the molecule leads to increased receptor affinity. New compounds were synthesized by acylation of N-arylpiperazines using 4- nitrophenylacetic acid. Obtained amides were converted in 1-(4-nitrophenethyl)-4- arylpiperazines using diborane in THF. Reduction of nitro compounds by Ra/Ni provided 1- (4-aminophenethyl)-4-arylpiperazines. Target arylamides were obtained by condensation 1- (4-aminophenethyl)-4-arylpiperazines with corresponding aryl acids in presence of propylphosphoric acid anhydride (PPAA) in DMF. All newly synthesized compounds were evaluated for their activity toward 5HT1a receptors by in vitro competitive displacement assay of [3H] 8-OH-DPAT. HEK cell line were used as a source of 5HT1a receptors. Introduction of 2-methoxy and 2,3-dichloro groups,as well as meta and para hydroxyl group in molecule resulted in increment of affinity toward 5HT1a receptors comparing to the parent compounds
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