548 research outputs found

    Game Theoretic Approach to the Stabilization of Heterogeneous Multiagent Systems Using Subsidy

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    We consider a multiagent system consisting of selfish and heterogeneous agents. Its behavior is modeled by multipopulation replicator dynamics, where payoff functions of populations are different from each other. In general, there exist several equilibrium points in the replicator dynamics. In order to stabilize a desirable equilibrium point, we introduce a controller called a government which controls the behaviors of agents by offering them subsidies. In previous work, it is assumed that the government determines the subsidies based on the populations the agents belong to. In general, however, the government cannot identify the members of each population. In this paper, we assume that the government observes the action of each agent and determines the subsidies based on the observed action profile. Then, we model the controlled behaviors of the agents using replicator dynamics with feedback. We derive a stabilization condition of the target equilibrium point in the replicator dynamics.Comment: 6 pages, IEEE Conference on Decision and Control, 201

    Combined theoretical and experimental approaches for development of squaraine dyes with small energy barrier for electron injection

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    A series of far-red sensitizing squaraine dyes has been systematically designed and synthesized in order to correlate the theoretically calculated values with their corresponding experimental parameters. Efforts have been directed towards determining the minimum thermodynamic energy barrier for the electron injection in the nanoporous TiO2 by logical molecular design. Theoretical calculations using Gaussian program package were performed for ground and excited states in both of the isolated gaseous state as well as in solution including the solvent effect using a self-consistent reaction field polarizable continuum model (PCM). Implementation of the PCM model or use of LSDA functional under TD-DFT calculations gives much better results for energetics as well as absorption maximum for all of the sensitizers used in this work. Newly designed symmetrical squaraine dye SQ-5 exhibits a minimum energy barrier of 0.16 eV for electron injection and shows photon harvesting behavior in far-red region with external photoconversion efficiency of 2.02% under simulated solar irradiation

    Parametric Optimization of Experimental Conditions for Dye-Sensitized Solar Cells based on Far-red Sensitive Squaraine Dye

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    A far-red sensitive unsymmetrical squaraine dye SQ-41 has been synthesized and subjected to the fabrication of dye-sensitized solar cells by varying the various parameters in order attain optimum photoconversion efficiency (η). It has been demonstrated that an optimum ratio of dye to coadsorber, thickness of mesoporous TiO2 layer, redox electrolyte and surface treatment are necessary to enhance overall external η. In the case of surface treatment, it has been shown to exhibit pronounced device performance when both of the FTO as well mesoporous TiO2 surfaces were treated with aqueous TiCl4. In spite of very high molar extinction coefficient of dye SQ-41, 10-12 µm thickness of mesoporous TiO2 was found to be necessary to attain the maximum η.India-Japan Expert Group Meeting on Biomolecular Electronics & Organic Nanotechnology for Environment Preservation (IJEGMBE 2015), December 23-26, 2015, Fukuoka, Japa

    A human transporter protein that mediates the final excretion step for toxic organic cations

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    In mammals, toxic electrolytes of endogenous and exogenous origin are excreted through the urine and bile. Before excretion, these compounds cross numerous cellular membranes in a transporter-mediated manner. However, the protein transporters involved in the final excretion step are poorly understood. Here, we show that MATE1, a human and mouse orthologue of the multidrug and toxin extrusion (MATE) family conferring multidrug resistance on bacteria, is primarily expressed in the kidney and liver, where it is localized to the luminal membranes of the urinary tubules and bile canaliculi. When expressed in HEK293 cells, MATE1 mediates H+-coupled electroneutral exchange of tetraethylammonium (TEA) and 1-methyl-4-phenylpyridinium (MPP). Its substrate specificity is similar to those of renal and hepatic H+-coupled organic cations (OCs) export. Thus, MATE1 appears to be the long searched for polyspecific OC exporter that directly transports toxic OCs into urine and bile.</p

    Investigation of the minimum driving force for dye regeneration utilizing model squaraine dyes for dye-sensitized solar cells

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    Combined theoretical and experimental approaches were implemented to design model far-red sensitive unsymmetrical squaraine dyes in order to estimate the minimum energy barrier required for dye regeneration. Our logical molecular design indicated that it is possible to have a fine control on the energetics within 0.2 eV only by the judicious selection of substituents and alkyl chain length keeping the main π-molecular framework the same. The utilization of the LSDA functional under TD-DFT calculations offered an effective and economical computational method for the reliable prediction of the energetics as well as the absorption maximum of the sensitizers. Among the designed dyes under investigation, SQ-75 exhibited the best photovoltaic performance, having a short-circuit current density of 10.92 mA cm−2, open circuit voltage of 0.57 V and a fill factor of 0.67, leading to a photoconversion efficiency of 4.25% despite having photon harvesting mainly in the far-red region. The best photon harvesting by SQ-75, even with an energy difference of only 0.12 eV between the energy of its highest occupied molecular orbital and redox energy level I−/I3− electrolyte, corroborates the possibility for dye regeneration with such a small driving force

    AMDORAP: Non-targeted metabolic profiling based on high-resolution LC-MS

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    <p>Abstract</p> <p>Background</p> <p>Liquid chromatography-mass spectrometry (LC-MS) utilizing the high-resolution power of an orbitrap is an important analytical technique for both metabolomics and proteomics. Most important feature of the orbitrap is excellent mass accuracy. Thus, it is necessary to convert raw data to accurate and reliable <it>m/z </it>values for metabolic fingerprinting by high-resolution LC-MS.</p> <p>Results</p> <p>In the present study, we developed a novel, easy-to-use and straightforward <it>m/z </it>detection method, AMDORAP. For assessing the performance, we used real biological samples, <it>Bacillus subtilis </it>strains 168 and MGB874, in the positive mode by LC-orbitrap. For 14 identified compounds by measuring the authentic compounds, we compared obtained <it>m/z </it>values with other LC-MS processing tools. The errors by AMDORAP were distributed within ±3 ppm and showed the best performance in <it>m/z </it>value accuracy.</p> <p>Conclusions</p> <p>Our method can detect <it>m/z </it>values of biological samples much more accurately than other LC-MS analysis tools. AMDORAP allows us to address the relationships between biological effects and cellular metabolites based on accurate <it>m/z </it>values. Obtaining the accurate <it>m/z </it>values from raw data should be indispensable as a starting point for comparative LC-orbitrap analysis. AMDORAP is freely available under an open-source license at <url>http://amdorap.sourceforge.net/</url>.</p

    Allogeneic offspring produced by induction of PD-L1 in spermatogonial stem cells via self-renewal stimulation

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    The testis is an immune-privileged organ. It is considered that the testis somatic microenvironment is responsible for immune suppression. However, immunological properties of spermatogonial stem cells (SSCs) have remained unknown. Here, we report the birth of allogeneic offspring by enhanced expression of immunosuppressive PD-L1 in SSCs. In vitro supplementation of GDNF and FGF2 increased expression of PD-L1 in SSCs. Cultured SSCs maintained allogeneic spermatogenesis that persisted for >1 year. However, depletion or gene editing of Pd-l1 family genes in SSCs prevented allogeneic spermatogenesis, which suggested that germ cells are responsible for suppression of the allogeneic response. PD-L1 was induced by activation of the MAPK14-BCL6B pathway, which drives self-renewal by reactive oxygen species (ROS) generation. By contrast, reduced ROS or Mapk14 deficiency downregulated PD-L1. Allogeneic offspring were born after SSC transplantation into congenitally infertile and chemically castrated mice. Thus, SSCs have unique immunological properties, which make allogeneic recipients into "surrogate fathers.

    ROS amplification drives mouse spermatogonial stem cell self-renewal

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    Reactive oxygen species (ROS) play critical roles in self-renewal division for various stem cell types. However, it remains unclear how ROS signals are integrated with self-renewal machinery. Here, we report that the MAPK14/MAPK7/BCL6B pathway creates a positive feedback loop to drive spermatogonial stem cell (SSC) self-renewal via ROS amplification. The activation of MAPK14 induced MAPK7 phosphorylation in cultured SSCs, and targeted deletion of Mapk14 or Mapk7 resulted in significant SSC deficiency after spermatogonial transplantation. The activation of this signaling pathway not only induced Nox1 but also increased ROS levels. Chemical screening of MAPK7 targets revealed many ROS-dependent spermatogonial transcription factors, of which BCL6B was found to initiate ROS production by increasing Nox1 expression via ETV5-induced nuclear translocation. Because hydrogen peroxide or Nox1 transfection also induced BCL6B nuclear translocation, our results suggest that BCL6B initiates and amplifies ROS signals to activate ROS-dependent spermatogonial transcription factors by forming a positive feedback loop
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