Application of complexing agent for lanthanoides separation by solvent extraction

International Nuclear Information System (INIS)

Jedinakova, V.; Dvorak, Z.; Blazek, P.

1988-01-01

The general characteristics are given of extraction separation of lanthanides by liquid separation in the presence of complex forming agents and the effects are discussed of the composition of the liquid and organic phase on their selective separation. Simple expressions may be derived on the basis of stability constants, for predicting the effects of the applied complex forming agents. The validity of the proposed mathematical models was confronted with experimental data and the confrontation confirmed that they may be used for modelling real systems. The proesented method allows to simulate the refining process from the known relationship of D Mi/Ma =f(c ma o ). (author). 3 figs., 3 tabs., 11 refs

Modelling complex systems of heterogeneous agents to better design sustainability transitions policy

NARCIS (Netherlands)

Mercure, J.F.A.; Pollitt, H.; Bassi, A.M.; Viñuales, J.E.; Edwards, N.R.

2016-01-01

This article proposes a fundamental methodological shift in the modelling of policy interventions for sustainability transitions in order to account for complexity (e.g. self-reinforcing mechanisms, such as technology lock-ins, arising from multi-agent interactions) and agent heterogeneity (e.g.

Studies on polyaspartamide gadolinium complexes as potential magnetic resonance imaging contrast agents

International Nuclear Information System (INIS)

Yan Guoping; Liu Maili; Li Liyun

2005-01-01

Purpose: A series of polyaspartamide gadolinium complexes containing pyridoxamine groups were studied as the potential magnetic resonance imaging (MRI) contrast agents for liver enhancement. Methods: These polyaspartamide gadolinium complexes were prepared and evaluated by relaxivity, acute toxicity studies and magnetic resonance imaging of the liver in rats. Results: These polyaspartamide gadolinium complexes have higher relaxation effectiveness than that of the clinically used gadolinium diethylenetriaminepentaacetic acid and possess the low intravenous acute toxicities to Institute for Cancer Research (ICR) mice. Magnetic resonance imaging of the liver in rats indicated that they greatly enhance the contrast of magnetic resonance images and provide prolonged intravascular duration in the liver. Conclusion: These results indicated that the polyaspartamide gadolinium complexes containing pyridoxamine groups could be considered as the appropriate MRI contrast agents for liver enhancement

Platinum(II)-gadolinium(III) complexes as potential single-molecular theranostic agents for cancer treatment.

Science.gov (United States)

Zhu, Zhenzhu; Wang, Xiaoyong; Li, Tuanjie; Aime, Silvio; Sadler, Peter J; Guo, Zijian

2014-11-24

Theranostic agents are emerging multifunctional molecules capable of simultaneous therapy and diagnosis of diseases. We found that platinum(II)-gadolinium(III) complexes with the formula [{Pt(NH3)2Cl}2GdL](NO3)2 possess such properties. The Gd center is stable in solution and the cytoplasm, whereas the Pt centers undergo ligand substitution in cancer cells. The Pt units interact with DNA and significantly promote the cellular uptake of Gd complexes. The cytotoxicity of the Pt-Gd complexes is comparable to that of cisplatin at high concentrations (≥0.1 mM), and their proton relaxivity is higher than that of the commercial magnetic resonance imaging (MRI) contrast agent Gd-DTPA. T1-weighted MRI on B6 mice demonstrated that these complexes can reveal the accumulation of platinum drugs in vivo. Their cytotoxicity and imaging capabilities make the Pt-Gd complexes promising theranostic agents for cancer treatment. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Labelling and Organ Distrbution Characterisics of 99mTc Galacturonate Complex Using Dithionite as Reducing Agent

International Nuclear Information System (INIS)

Al Hilli, A.M.; Mirza, K.S.; Al Noori, T.H.J.

2000-01-01

The labelling conditions of 99m T c-galacturonate complex using dithionite as reducing agent for periechnetate have been described. GCS-method has been applied for radiochemical determination of the labelled complex. At a constant amount of the ligand (50mg) in the preparation, high labelling of 99m Tc -galacturonate complex was obtained in the presence of the reducing agent. The effect of pH on the labelling yield have show that labelling occurs only at near neutral to slightly alkaline pH. The organ distribution results of 99m Tc -galacturonate complex as a function of the reducing agent concentration was achieved in rats. On using 8mg of dithionite as reducing agent,the activity uptake in the kindneys was significantly low, while in the bones was higher, but decreased after 1 hr. of injection. This,however is due to the instability of the labelled complex releasing pertechnetate which was evident by the increase of activity in the stomach. The organ distribution picture of the complex has been reversed by increasing the concentration of dithionite(16 mg) in the preparation,where the activity uptake in the kidnys was increased to higher level and in the bones was decreased.The activity in the stomach was rather low indicating a more stable complex towards oxidation or decomposition

Biological evaluation of 99mTC cis-Pt iminoacetic acid complexes as tumour imaging agents

International Nuclear Information System (INIS)

Awaluddin, A.; Jacobs, J.J.; Bourne, D.W.; Maddalena, D.J.; Wilson, J.G.; Boyd, D.W.

1987-01-01

The biodistributions of three new 99m Tc labelled cis-platinum bifunctional tumour imaging agents were examined in mice bearing a certain type of sarcoma between 15 minutes and 24 hours post injection. The three complexes were excreted primarily via the renal pathway into the urine but at quite different rates. All complexes had some affinity for the tumour, but complexes III had the greatest, with tumour to blood and tumour to muscle rates at 24 hours in excess of 10:1 and 18:1. Biodistribution results were calculated using Tiscon Program. Suggesting that the three complexes may be useful as tumour imaging agents. (M.E.L.) [es

Agent-Based and Macroscopic Modeling of the Complex Socio-Economic Systems

Directory of Open Access Journals (Sweden)

Aleksejus Kononovičius

2013-08-01

Full Text Available Purpose – The focus of this contribution is the correspondence between collective behavior and inter-individual interactions in the complex socio-economic systems. Currently there is a wide selection of papers proposing various models for the both collective behavior and inter-individual interactions in the complex socio-economic systems. Yet the papers directly relating these two concepts are still quite rare. By studying this correspondence we discuss a cutting edge approach to the modeling of complex socio-economic systems. Design/methodology/approach – The collective behavior is often modeled using stochastic and ordinary calculus, while the inter-individual interactions are modeled using agent-based models. In order to obtain the ideal model, one should start from these frameworks and build a bridge to reach another. This is a formidable task, if we consider the top-down approach, namely starting from the collective behavior and moving towards inter-individual interactions. The bottom-up approach also fails, if complex inter-individual interaction models are considered, yet in this case we can start with simple models and increase the complexity as needed. Findings – The bottom-up approach, considering simple agent-based herding model as a model for the inter-individual interactions, allows us to derive certain macroscopic models of the complex socio-economic systems from the agent-based perspective. This provides interesting insights into the collective behavior patterns observed in the complex socio-economic systems. Research limitations/implications –The simplicity of the agent-based herding model might be considered to be somewhat limiting. Yet this simplicity implies that the model is highly universal. It reproduces universal features of social behavior and also can be further extended to fit different socio-economic scenarios. Practical implications – Insights provided in this contribution might be used to modify existing

Use of tetracycline as complexing agent in analytical chemistry

International Nuclear Information System (INIS)

Nastasi, M.J.C.; Saiki, M.; Lima, F.W.

1977-01-01

The behavior of tetracyline as complexing agent in solvent extraction studies is presented. The extraction curves for the lanthanide elements, scandium, thorium, uranium and neptunium, are determined for the extraction system benzyl alcohol-tetracycline, as well as the acid and extractant dependences of extraction of the lanthanide elements. Separation of neptunium from uranium is formed by carrying out the extraction experiment at a proper pH value. Use is made of masking agents namely, ethylenediaminetetraacetic acid (EDTA) and diethylenetriaminepentaacetic acid (DTPA), in order to obtain separations of uranium from scadium and lanthanides as well as of uranium and thorium, respectively. The extraction experiments are carried out by using radioisotopes of each element, except for uranium in which case the determinations are by using epithermal neutron activation analysis [pt

Complex responses to alkylating agents

International Nuclear Information System (INIS)

Samson, L.D.

2003-01-01

Using Affymetrix oligonucleotide GeneChip analysis, we previously found that, upon exposure to the simple alkylating agent methylmethane sulfonate, the transcript levels for about one third of the Saccharomyces cerevisiae genome (∼2,000 transcripts) are induced or repressed during the first hour or two after exposure. In order to determine whether the responsiveness of these genes has any relevance to the protection of cells against alkylating agents we have undertaken several follow-up studies. First, we explored the specificity of this global transcriptional response to MMS by measuring the global response of S. cerevisiae to a broad range of agents that are known to induce DNA damage. We found that each agent produced a very different mRNA transcript profile, even though the exposure doses produced similar levels of toxicity. We also found that the selection of genes that respond to MMS is highly dependent upon what cell cycle phase the cells are in at the time of exposure. Computational clustering analysis of the dataset derived from a large number of exposures identified several promoter motifs that are likely to control some of the regulons that comprise this large set of genes that are responsive to DNA damaging agents. However, it should be noted that these agents damage cellular components other than DNA, and that the responsiveness of each gene need not be in response to DNA damage per se. We have also begun to study the response of other organisms to alkylating agents, and these include E. coli, cultured mouse and human cells, and mice. Finally, we have developed a high throughput phenotypic screening method to interrogate the role of all non-essential S. cerevisiae genes (about 4,800) in protecting S. cerevisiae against the deleterious effects of alkylating agents; we have termed this analysis 'genomic phenotyping'. This study has uncovered a plethora of new pathways that play a role in the recovery of eukaryotic cells after exposure to toxic

Modeling and simulation of complex systems a framework for efficient agent-based modeling and simulation

CERN Document Server

Siegfried, Robert

2014-01-01

Robert Siegfried presents a framework for efficient agent-based modeling and simulation of complex systems. He compares different approaches for describing structure and dynamics of agent-based models in detail. Based on this evaluation the author introduces the "General Reference Model for Agent-based Modeling and Simulation" (GRAMS). Furthermore he presents parallel and distributed simulation approaches for execution of agent-based models -from small scale to very large scale. The author shows how agent-based models may be executed by different simulation engines that utilize underlying hard

Mitochondrial complex II, a novel target for anti-cancer agents

Czech Academy of Sciences Publication Activity Database

Klučková, Katarína; Bezawork-Geleta, A.; Rohlena, Jakub; Dong, L.; Neužil, Jiří

2013-01-01

Roč. 1827, č. 5 (2013), s. 552-564 ISSN 0005-2728 R&D Projects: GA ČR(CZ) GAP301/10/1937; GA ČR GAP301/12/1851 Institutional research plan: CEZ:AV0Z50520701 Keywords : Mitochondrion * Complex II * Anti-cancer agent Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 4.829, year: 2013

Complexity and agent-based modelling in urban research

DEFF Research Database (Denmark)

Fertner, Christian

influence on the bigger system. Traditional scientific methods or theories often tried to simplify, not accounting complex relations of actors and decision-making. The introduction of computers in simulation made new approaches in modelling, as for example agent-based modelling (ABM), possible, dealing......Urbanisation processes are results of a broad variety of actors or actor groups and their behaviour and decisions based on different experiences, knowledge, resources, values etc. The decisions done are often on a micro/individual level but resulting in macro/collective behaviour. In urban research...

Use of tetracycline as complexing agent in radiochemical separations

International Nuclear Information System (INIS)

Saiki, M.; Nastasi, M.J.C.; Lima, F.W.

1981-01-01

The use of the antibiotic agent tetracycline (TC) for analytical purposes in solvent extraction procedures is presented. Individual extraction curves for the lanthanides, zinc, scandium, uranium, thorium, neptunium and protactinium were obtained. Separation of those elements from one another, and of uranium from selenium, bromine, antimony, barium, tantalum and tungsten was carried out. In all cases benzyl alcohol was the diluent used to dissolve tetracycline hydrochloride. Sodium chloride was used as supporting electrolyte for the lanthanide separations and sodium perchlorate for the other elements mentioned. Stability or formation constants for the lanthanide complexes as well as for thorium complex with tetracycline were determined by using the methods of average number of ligands, the limiting value (for thorium), the two parameters and the weighted least squares. For the lanthanides, the stability constants of the complexes Ln(TC) 3 go from 9.35+-0.22 for lanthanum up to 10.84+-0.11 for lutetium. For the Th(TC) 4 complex the formation constant is equal to 24.6+-0.3. Radioisotopes of the respective elements were used as tracers for the determinations. (author)

Complex social waves of giant honeybees provoked by a dummy wasp support the special-agent hypothesis.

Science.gov (United States)

Kastberger, Gerald; Weihmann, Frank; Hoetzl, Thomas

2010-03-01

The social waves in giant honeybees termed as shimmering are more complex than mexican waves. it has been demonstrated1 that shimmering is triggered by special agents at the nest surface. in this paper, we have used a nest that originated by amalgamation of two previously separated nests and stimulated waves by a dummy wasp moved on a miniature cable car. we illustrate the plausibility of the special-agent hypothesis1 also for complex shimmering processes.

Complex social waves of giant honeybees provoked by a dummy wasp support the special-agent hypothesis

OpenAIRE

Kastberger, Gerald; Weihmann, Frank; Hoetzl, Thomas

2010-01-01

The social waves in giant honeybees termed as shimmering are more complex than mexican waves. it has been demonstrated1 that shimmering is triggered by special agents at the nest surface. in this paper, we have used a nest that originated by amalgamation of two previously separated nests and stimulated waves by a dummy wasp moved on a miniature cable car. we illustrate the plausibility of the special-agent hypothesis1 also for complex shimmering processes.

The Evolution of ICT Markets: An Agent-Based Model on Complex Networks

Science.gov (United States)

Zhao, Liangjie; Wu, Bangtao; Chen, Zhong; Li, Li

Information and communication technology (ICT) products exhibit positive network effects.The dynamic process of ICT markets evolution has two intrinsic characteristics: (1) customers are influenced by each others’ purchasing decision; (2) customers are intelligent agents with bounded rationality.Guided by complex systems theory, we construct an agent-based model and simulate on complex networks to examine how the evolution can arise from the interaction of customers, which occur when they make expectations about the future installed base of a product by the fraction of neighbors who are using the same product in his personal network.We demonstrate that network effects play an important role in the evolution of markets share, which make even an inferior product can dominate the whole market.We also find that the intensity of customers’ communication can influence whether the best initial strategy for firms is to improve product quality or expand their installed base.

Complex agent networks explaining the HIV epidemic among homosexual men in Amsterdam

NARCIS (Netherlands)

Mei, S.; Sloot, P.M.A.; Quax, R.; Zhu, Y.; Wang, W.

2010-01-01

Simulating the spreading of the human immunodeficiency virus (HIV) epidemic requires a detailed description of the population network, especially for small populations in which individuals can be represented in detail and accuracy. In this paper, we introduce the concept of a complex agent network

The influence of reducing agents on the composition of technetium-99 complexes: implications for technetium-99m radiopharmaceutical preparation

International Nuclear Information System (INIS)

Baldas, J.; Bonnyman, J.; Pojer, P.M.; Williams, G.A.

1981-05-01

The use of hydrazine or formamidine sulphinic acid as reducing agents in the presence of 99 Tc-pertechnetate anion and the diethyldithiocarbamate ligand has been found to yield complexes containing Tc triple bond N and Tc=CO bonds respectively. The nitrido nitrogen atom and the carbon monoxide incorporated in these complexes as ligands originate from the reducing agents themselves. It is apparent that when reducing agents such as hydrazine or formamidine sulphinic acid are used in the preparation of Tc-99m-radiopharmaceuticals, the possibility of the formation of complexes structurally different to those obtained by use of stannous chloride must be considered

Modeling the Internet of Things, Self-Organizing and Other Complex Adaptive Communication Networks: A Cognitive Agent-Based Computing Approach.

Directory of Open Access Journals (Sweden)

Samreen Laghari

Full Text Available Computer Networks have a tendency to grow at an unprecedented scale. Modern networks involve not only computers but also a wide variety of other interconnected devices ranging from mobile phones to other household items fitted with sensors. This vision of the "Internet of Things" (IoT implies an inherent difficulty in modeling problems.It is practically impossible to implement and test all scenarios for large-scale and complex adaptive communication networks as part of Complex Adaptive Communication Networks and Environments (CACOONS. The goal of this study is to explore the use of Agent-based Modeling as part of the Cognitive Agent-based Computing (CABC framework to model a Complex communication network problem.We use Exploratory Agent-based Modeling (EABM, as part of the CABC framework, to develop an autonomous multi-agent architecture for managing carbon footprint in a corporate network. To evaluate the application of complexity in practical scenarios, we have also introduced a company-defined computer usage policy.The conducted experiments demonstrated two important results: Primarily CABC-based modeling approach such as using Agent-based Modeling can be an effective approach to modeling complex problems in the domain of IoT. Secondly, the specific problem of managing the Carbon footprint can be solved using a multiagent system approach.

Modeling the Internet of Things, Self-Organizing and Other Complex Adaptive Communication Networks: A Cognitive Agent-Based Computing Approach.

Science.gov (United States)

Laghari, Samreen; Niazi, Muaz A

2016-01-01

Computer Networks have a tendency to grow at an unprecedented scale. Modern networks involve not only computers but also a wide variety of other interconnected devices ranging from mobile phones to other household items fitted with sensors. This vision of the "Internet of Things" (IoT) implies an inherent difficulty in modeling problems. It is practically impossible to implement and test all scenarios for large-scale and complex adaptive communication networks as part of Complex Adaptive Communication Networks and Environments (CACOONS). The goal of this study is to explore the use of Agent-based Modeling as part of the Cognitive Agent-based Computing (CABC) framework to model a Complex communication network problem. We use Exploratory Agent-based Modeling (EABM), as part of the CABC framework, to develop an autonomous multi-agent architecture for managing carbon footprint in a corporate network. To evaluate the application of complexity in practical scenarios, we have also introduced a company-defined computer usage policy. The conducted experiments demonstrated two important results: Primarily CABC-based modeling approach such as using Agent-based Modeling can be an effective approach to modeling complex problems in the domain of IoT. Secondly, the specific problem of managing the Carbon footprint can be solved using a multiagent system approach.

Actinide-specific complexing agents: their structural and solution chemistry

International Nuclear Information System (INIS)

Raymond, K.N.; Freeman, G.E.; Kappel, M.J.

1983-07-01

The synthesis of a series of tetracatecholate ligands designed to be specific for Pu(IV) and other actinide(IV) ions has been achieved. Although these compounds are very effective as in vivo plutonium removal agents, potentiometric and voltammetric data indicate that at neutral pH full complexation of the Pu(IV) ion by all four catecholate groups does not occur. Spectroscopic results indicate that the tetracatecholates, 3,4,3-LICAMS and 3,4,3-LICAMC, complex Am(III). The Am(IV)/(III)-catecholate couple (where catecholate = 3,4,3-LICAMS or 3,4,3-LICAMC) is not observed, but may not be observable due to the large currents associated with ligand oxidation. However, within the potential range where ligand oxidation does not occur, these experiments indicate that the reduction potential of free Am(IV)/(III) is probably greater than or equal to + 2.6 V vs NHE or higher. Proof of the complexation of americium in the trivalent oxidation state by 3,4,3-LICAMS and 3,4,3-LICAMC elimates the possibility of tetracatholates stabilizing Am(IV) in vivo

Photolabile ruthenium complexes to cage and release a highly cytotoxic anticancer agent.

Science.gov (United States)

Wei, Jianhua; Renfrew, Anna K

2018-02-01

CHS-828 (N-(6-(4-chlorophenoxy)hexyl)-N'-cyano-N″-4-pyridyl guanidine) is an anticancer agent with low bioavailability and high systemic toxicity. Here we present an approach to improve the therapeutic profile of the drug using photolabile ruthenium complexes to generate light-activated prodrugs of CHS-828. Both prodrug complexes are stable in the dark but release CHS-828 when irradiated with visible light. The complexes are water-soluble and accumulate in tumour cells in very high concentrations, predominantly in the mitochondria. Both prodrug complexes are significantly less cyototoxic than free CHS-828 in the dark but their toxicity increases up to 10-fold in combination with visible light. The cellular responses to light treatment are consistent with release of the cytotoxic CHS-828 ligand. Copyright © 2017 Elsevier Inc. All rights reserved.

Paramagnetic metal complexes as potential relaxation agents for NMR imaging

International Nuclear Information System (INIS)

Coroiu, Ilioara; Demco, D. E.; Darabont, Al.; Bogdan, M.

1997-01-01

The development of nuclear magnetic resonance (NMR) imaging technique as a clinical diagnostic modality has prompted the need for a new class of pharmaceuticals. These drugs must be administered to a patient in order to enhance the image contrast between the normal and diseased tissue and/or indicate the status of organ function or blood flow. Paramagnetic compounds are presently undergoing extensive evaluation as contrast agents in magnetic resonance imaging (MRI). These agents increase contrast in MRI by differentially localizing in tissue where they increase the relaxation rates of nearby water protons. The longitudinal R 1 and transverse R 2 relaxivities were measured as a function of molar concentrations for some new paramagnetic complexes like the following: dysprosium, erbium and gadolinium citrates, gadolinium methylene diphosphonate, dysprosium and gadolinium iminodiacetate, manganese para-aminobenzoate and copper nicotinate. The available theoretical approaches for quantitative understanding are presented. (authors)

4-aminoquinoline analogues and its platinum (II) complexes as antimalarial agents.

Science.gov (United States)

de Souza, Nicolli Bellotti; Carmo, Arturene M L; Lagatta, Davi C; Alves, Márcio José Martins; Fontes, Ana Paula Soares; Coimbra, Elaine Soares; da Silva, Adilson David; Abramo, Clarice

2011-07-01

The high incidence of malaria and drug-resistant strains of Plasmodium have turned this disease into a problem of major health importance. One of the approaches used to control it is to search for new antimalarial agents, such as quinoline derivates. This class of compounds composes a broad group of antimalarial agents, which are largely employed, and inhibits the formation of β-haematin (malaria pigment), which is lethal to the parasite. More specifically, 4-aminoquinoline derivates represent potential sources of antimalarials, as the example of chloroquine, the most used antimalarial worldwide. In order to assess antimalarial activity, 12 4-aminoquinoline derived drugs were obtained and some of these derivatives were used to obtain platinum complexes platinum (II). These compounds were tested in vivo in a murine model and revealed remarkable inhibition of parasite multiplication values, whose majority ranged from 50 to 80%. In addition they were not cytotoxic. Thus, they may be object of further research for new antimalarial agents. Copyright © 2011 Elsevier Masson SAS. All rights reserved.

Linking Bayesian and agent-based models to simulate complex social-ecological systems in semi-arid regions

Directory of Open Access Journals (Sweden)

Aloah J Pope

2015-08-01

Full Text Available Interdependencies of ecologic, hydrologic, and social systems challenge traditional approaches to natural resource management in semi-arid regions. As a complex social-ecological system, water demands in the Sonoran Desert from agricultural and urban users often conflicts with water needs for its ecologically-significant riparian corridors. To explore this system, we developed an agent-based model to simulate complex feedbacks between human decisions and environmental conditions in the Rio Sonora Watershed. Cognitive mapping in conjunction with stakeholder participation produced a Bayesian model of conditional probabilities of local human decision-making processes resulting to changes in water demand. Probabilities created in the Bayesian model were incorporated into the agent-based model, so that each agent had a unique probability to make a positive decision based on its perceived environment at each point in time and space. By using a Bayesian approach, uncertainty in the human decision-making process could be incorporated. The spatially-explicit agent-based model simulated changes in depth-to-groundwater by well pumping based on an agent’s water demand. Changes in depth-to-groundwater feedback to influence agent behavior, as well as determine unique vegetation classes within the riparian corridor. Each vegetation class then provides varying stakeholder-defined quality values of ecosystem services. Using this modeling approach allowed us to examine effects on both the ecological and social system of semi-arid riparian corridors under various scenarios. The insight provided by the model contributes to understanding how specific interventions may alter the complex social-ecological system in the future.

Lipid solubility of the platinum group metals Pt, Pd and Rh in dependence on the presence of complexing agents

International Nuclear Information System (INIS)

Zimmermann, Sonja; Menzel, Christoph M.; Stueben, Doris; Taraschewski, Horst; Sures, Bernd

2003-01-01

All complexing agents had a significant influence on octanol solubility of PGM. - Investigations on the bioaccumulation of the platinum group metals (PGM) Pt, Pd and Rh in aquatic organisms are of growing interest in environmental research due to the increasing emission of these metals by motor vehicles with catalytic converters. Until now, nothing is known about the possible influence of complexing agents on the bioaccumulation capacity of these precious metals. According to the partition coefficient between 1-octanol and water (P OW ) as a measure of bioaccumulation, in this study a simple shaking method was performed in order to investigate the effects of different complexing agents (L-methionine, thio urea, EDTA, humic substances, bile compounds) on the octanol solubility of the PGM. The results demonstrated a significant influence of all agents used. L-Methionine and thio urea decreased the lipid solubility. In contrast, the presence of EDTA, humic substances and especially bile caused a higher transfer of metals in the octanol phase. For most complexing agents tested, the transfer of Pd to the lipid phase was significantly higher compared with Rh and Pt, except for bile acid where the highest octanol solubility was found for Pt. Recent experimental results on PGM accumulation in zebra mussels confirm a high bioaccumulation of Pd which could be predicted from the lipid solubility

Lipid solubility of the platinum group metals Pt, Pd and Rh in dependence on the presence of complexing agents

Energy Technology Data Exchange (ETDEWEB)

Zimmermann, Sonja; Menzel, Christoph M.; Stueben, Doris; Taraschewski, Horst; Sures, Bernd

2003-07-01

All complexing agents had a significant influence on octanol solubility of PGM. - Investigations on the bioaccumulation of the platinum group metals (PGM) Pt, Pd and Rh in aquatic organisms are of growing interest in environmental research due to the increasing emission of these metals by motor vehicles with catalytic converters. Until now, nothing is known about the possible influence of complexing agents on the bioaccumulation capacity of these precious metals. According to the partition coefficient between 1-octanol and water (P{sub OW}) as a measure of bioaccumulation, in this study a simple shaking method was performed in order to investigate the effects of different complexing agents (L-methionine, thio urea, EDTA, humic substances, bile compounds) on the octanol solubility of the PGM. The results demonstrated a significant influence of all agents used. L-Methionine and thio urea decreased the lipid solubility. In contrast, the presence of EDTA, humic substances and especially bile caused a higher transfer of metals in the octanol phase. For most complexing agents tested, the transfer of Pd to the lipid phase was significantly higher compared with Rh and Pt, except for bile acid where the highest octanol solubility was found for Pt. Recent experimental results on PGM accumulation in zebra mussels confirm a high bioaccumulation of Pd which could be predicted from the lipid solubility.

Exploring complex dynamics in multi agent-based intelligent systems: Theoretical and experimental approaches using the Multi Agent-based Behavioral Economic Landscape (MABEL) model

Science.gov (United States)

Alexandridis, Konstantinos T.

This dissertation adopts a holistic and detailed approach to modeling spatially explicit agent-based artificial intelligent systems, using the Multi Agent-based Behavioral Economic Landscape (MABEL) model. The research questions that addresses stem from the need to understand and analyze the real-world patterns and dynamics of land use change from a coupled human-environmental systems perspective. Describes the systemic, mathematical, statistical, socio-economic and spatial dynamics of the MABEL modeling framework, and provides a wide array of cross-disciplinary modeling applications within the research, decision-making and policy domains. Establishes the symbolic properties of the MABEL model as a Markov decision process, analyzes the decision-theoretic utility and optimization attributes of agents towards comprising statistically and spatially optimal policies and actions, and explores the probabilogic character of the agents' decision-making and inference mechanisms via the use of Bayesian belief and decision networks. Develops and describes a Monte Carlo methodology for experimental replications of agent's decisions regarding complex spatial parcel acquisition and learning. Recognizes the gap on spatially-explicit accuracy assessment techniques for complex spatial models, and proposes an ensemble of statistical tools designed to address this problem. Advanced information assessment techniques such as the Receiver-Operator Characteristic curve, the impurity entropy and Gini functions, and the Bayesian classification functions are proposed. The theoretical foundation for modular Bayesian inference in spatially-explicit multi-agent artificial intelligent systems, and the ensembles of cognitive and scenario assessment modular tools build for the MABEL model are provided. Emphasizes the modularity and robustness as valuable qualitative modeling attributes, and examines the role of robust intelligent modeling as a tool for improving policy-decisions related to land

Multi-agent evolutionary systems for the generation of complex virtual worlds

Directory of Open Access Journals (Sweden)

J. Kruse

2016-01-01

Full Text Available Modern films, games and virtual reality applications are dependent on convincing computer graphics. Highly complex models are a requirement for the successful delivery of many scenes and environments. While workflows such as rendering, compositing and animation have been streamlined to accommodate increasing demands, modelling complex models is still a laborious task. This paper introduces the computational benefits of an Interactive Genetic Algorithm (IGA to computer graphics modelling while compensating the effects of user fatigue, a common issue with Interactive Evolutionary Computation. An intelligent agent is used in conjunction with an IGA that offers the potential to reduce the effects of user fatigue by learning from the choices made by the human designer and directing the search accordingly. This workflow accelerates the layout and distribution of basic elements to form complex models. It captures the designer’s intent through interaction, and encourages playful discovery.

Characterization of radionuclide-chelating agent complexes found in low-level radioactive decontamination waste. Literature review

International Nuclear Information System (INIS)

Serne, R.J.; Felmy, A.R.; Cantrell, K.J.; Krupka, K.M.; Campbell, J.A.; Bolton, H. Jr.; Fredrickson, J.K.

1996-03-01

The US Nuclear Regulatory Commission is responsible for regulating the safe land disposal of low-level radioactive wastes that may contain organic chelating agents. Such agents include ethylenediaminetetraacetic acid (EDTA), diethylenetriaminepentaacetic acid (DTPA), picolinic acid, oxalic acid, and citric acid, and can form radionuclide-chelate complexes that may enhance the migration of radionuclides from disposal sites. Data from the available literature indicate that chelates can leach from solidified decontamination wastes in moderate concentration (1--100 ppm) and can potentially complex certain radionuclides in the leachates. In general it appears that both EDTA and DTPA have the potential to mobilize radionuclides from waste disposal sites because such chelates can leach in moderate concentration, form strong radionuclide-chelate complexes, and can be recalcitrant to biodegradation. It also appears that oxalic acid and citric acid will not greatly enhance the mobility of radionuclides from waste disposal sites because these chelates do not appear to leach in high concentration, tend to form relatively weak radionuclide-chelate complexes, and can be readily biodegraded. In the case of picolinic acid, insufficient data are available on adsorption, complexation of key radionuclides (such as the actinides), and biodegradation to make definitive predictions, although the available data indicate that picolinic acid can chelate certain radionuclides in the leachates

Characterization of radionuclide-chelating agent complexes found in low-level radioactive decontamination waste. Literature review

Energy Technology Data Exchange (ETDEWEB)

Serne, R.J.; Felmy, A.R.; Cantrell, K.J.; Krupka, K.M.; Campbell, J.A.; Bolton, H. Jr.; Fredrickson, J.K. [Pacific Northwest National Lab., Richland, WA (United States)

1996-03-01

The US Nuclear Regulatory Commission is responsible for regulating the safe land disposal of low-level radioactive wastes that may contain organic chelating agents. Such agents include ethylenediaminetetraacetic acid (EDTA), diethylenetriaminepentaacetic acid (DTPA), picolinic acid, oxalic acid, and citric acid, and can form radionuclide-chelate complexes that may enhance the migration of radionuclides from disposal sites. Data from the available literature indicate that chelates can leach from solidified decontamination wastes in moderate concentration (1--100 ppm) and can potentially complex certain radionuclides in the leachates. In general it appears that both EDTA and DTPA have the potential to mobilize radionuclides from waste disposal sites because such chelates can leach in moderate concentration, form strong radionuclide-chelate complexes, and can be recalcitrant to biodegradation. It also appears that oxalic acid and citric acid will not greatly enhance the mobility of radionuclides from waste disposal sites because these chelates do not appear to leach in high concentration, tend to form relatively weak radionuclide-chelate complexes, and can be readily biodegraded. In the case of picolinic acid, insufficient data are available on adsorption, complexation of key radionuclides (such as the actinides), and biodegradation to make definitive predictions, although the available data indicate that picolinic acid can chelate certain radionuclides in the leachates.

Characteristics of gadolinium-DTPA complex: a potential NMR contrast agent

International Nuclear Information System (INIS)

Weinmann, H.J.; Brasch, R.C.; Press, W.R.; Wesbey, G.E.

1984-01-01

Chelation of the rare-earth element gadolinium (Gd) with diethylenetriaminepentaacetic acid (DTPA) results in a strongly paramagnetic, stable complex that is well tolerated in animals. The strongly paramagnetic gadolinium complex reduces hydrogen-proton relaxation times even in low concentrations (less than 0.01 mmol/L). The pharmacokinetic behavior of intravenously delivered Gd-DTPA is similar to the well known iodinated contrast agents used in urography and angiography; excretion is predominately through the kidneys with greater than 90% recovery in 24 hr. The intravenous LD 50 of the meglumine salt of Gd-DTPA is 10 mmol/kg for the rat; in vivo there is no evidence of dissociation of the gadolinium ion from the DTPA ligand. The combination of strong proton relaxation, in-vivo stability, rapid urinary excretion, and high tolerance favors the further development and the potential clinical application of gadolinium-DTPA as a contrast enhancer in magnetic resonance imaging

Effect of complexing agent on the photoelectrochemical properties of bath deposited CdS thin films

International Nuclear Information System (INIS)

Patil, S.B.; Singh, A.K.

2010-01-01

In the present paper photoelectrochemical (PEC) performance of bath deposited CdS thin films based on complexing agents i.e. ammonia and triethanolamine (TEA) has been discussed. Effect of annealing has also been analyzed. The as-deposited and annealed (at 523 K for 1 h in air) films were characterized by X-ray diffraction (XRD), ultraviolet-visible (UV-vis) absorption spectroscopy, SEM, electrochemical impedance spectroscopy (EIS), and PEC properties. XRD studies revealed that the films were nanocrystalline in nature with mixed hexagonal and cubic phases. TEA complex resulted in better crystallinity. Further improvement in the crystallinity of the films was observed after air annealing. The marigold flower-like structure, in addition to flakes morphology, was observed with TEA complex, whereas for ammonia complex only flakes morphology was observed. The UV-vis absorption studies revealed that the optical absorption edge for the films with ammonia and TEA complex was around 475 nm and 500 nm, respectively. Annealing of the films resulted in red shift in the UV-vis absorption. The PEC cell performance of CdS films was found to be strongly affected by crystallinity and morphology of the films resulted due to complexing agent and annealing. The air annealed film deposited using TEA complex showed maximum short circuit current density (J sc ) and open circuit voltage (V oc ) i.e. 99 μA/cm 2 and 376 mV respectively, under 10 mW/cm 2 of illumination. The films deposited using TEA complex showed good stability under PEC cell conditions.

Effect of different complexing agents on the properties of chemical-bath-deposited ZnS thin films

Energy Technology Data Exchange (ETDEWEB)

Liu, Jun; Wei, Aixiang, E-mail: weiax@gdut.edu.cn; Zhao, Yu

2014-03-05

Highlights: • To fabricate high quality ZnS films need to promote the ion-by-ion process and restrain cluster-by-cluster process. • The complexation ability of tri-sodium citrate is stronger than that of hydrazine hydrate. • The nucleation density of nuclei determine the performance of ZnS thin films. -- Abstract: Zinc sulfide (ZnS) thin films were deposited on glass substrates using the chemical bath deposition (CBD) technique. The effects of different complexing agents (tri-sodium citrate, hydrazine hydrate) and their concentrations on the structure, composition, morphology, optical properties and growth mechanism of ZnS thin films were investigated. The results indicated that the chemical-bath-deposited ZnS thin films exhibit poor crystallinity and a high Zn/S atomic ratio with an average transmittance of 75% in the range of visible light. The ZnS thin films prepared using hydrazine hydrate as the complexing agent present a more compact surface, a smaller average particle size, and a sharper absorption edge at 300–340 nm compared with those prepared using tri-sodium citrate. Based on our experimental observations and analysis, we conclude that the predominant growth mechanism of ZnS thin films is an ion-by-ion process. The nucleation density of Zn(OH){sub 2} nuclei on the substrate in the initial stage produces the different morphologies and properties of the ZnS thin films prepared using the two complexing agents.

Particle size and shape modification of hydroxyapatite nanostructures synthesized via a complexing agent-assisted route

International Nuclear Information System (INIS)

Mohandes, Fatemeh; Salavati-Niasari, Masoud

2014-01-01

In this work, hydroxyapatite (HAP), Ca 10 (PO 4 ) 6 (OH) 2 , nanostructures including nanorods, nanobundles and nanoparticles have been prepared via a simple precipitation method. In the present method, Ca(NO 3 ) 2 ·4H 2 O and (NH 4 ) 2 HPO 4 were used as calcium and phosphorus precursors, respectively. Besides, the Schiff bases derived from 2-hydroxyacetophenone and different diamines were used as complexing agents for the in situ formation of Ca 2+ complexes. The formation mechanism of 0-D and 1-D nanostructures of HAP was also considered. When the complexing agents could coordinate to the Ca 2+ ions through N and O atoms to form the [CaN 2 O 2 ] 2+ complexes, HAP nanoparticles were generated. On the other hand, nanorods and nanobundles of HAP were obtained by forming the [CaN 2 ] 2+ as well as [CaO 2 ] 2+ complexes in the reaction solution. This work is the first successful synthesis of pure HAP nanostructures in the presence of Schiff bases instead of using the common surfactants. - Highlights: • HAP nanostructures have been prepared by a simple precipitation method. • To control shape and particle size of HAP, different Schiff bases were employed. • 0-D and 1-D HAP nanostructures have been formed by this method

Effect of complexing agents and pH on microstructure and tribological properties of Co-W coatings produced by double pulse electrodeposition

International Nuclear Information System (INIS)

Su Fenghua; Liu Cansen; Huang Ping

2012-01-01

The Co-W coatings were produced by double pulse electrodeposition from aqueous bath with cobalt sulphate and sodium tungstate. Effect of complexing agent and pH value in the plating bath on the microstructure, morphology and hardness of the electrodeposited Co-W coatings were investigated using an X-ray diffraction (XRD), scanning electron microscope (SEM) and a Vickers hardness tester, respectively. The friction and wear properties of the Co-W coatings deposited from different baths were evaluated with a ball-on-disk UMT-3MT tribometer. The correlation among the electrodepositing condition that varied with the complexing agent or pH value, the microstructure and the tribological properties of the deposited Co-W coatings were discussed. The results show that the complexing agent and pH value significantly affect the microstructure and tribological properties of the electrodeposited Co-W coatings. The sodium citrate is the best complexing agent to improve the tribological properties of the electrodeposited Co-W coatings at pH 6.0, followed by the sodium gluconate. The Co-W coatings electrodeposited from the near neutral bath can obtain better tribological properties than those deposited from strong acid or strong alkaline bath. The differences of the tribological properties for Co-W coatings from different baths were attributed to their different hardness, crystal structure and morphological characterizations, which can be optimized by the electrodepositing condition, i.e., the complexing agent and pH value in bath.

Interaction of natural complexing agents with soil bound heavy metals -geochemical and environmental technical aspects

International Nuclear Information System (INIS)

Fischer, K.

1994-01-01

The sanitation of heavy metal polluted soils requires the application of an adequate technology, which should be consistent in its ecological aims and methodology. Therefore a research programme has been developed at the 'Institute of Ecological Chemistry' of the 'GSF-Research Center', Neuherberg, which has its starting point in the study of influences of natural organic complexing agents on the chemical activity and dynamic of heavy metals in soils. The groundlaying idea is to elevate the concentration of complexing agents in the soil solution by additional application and possible stimulation of their microbial production to such an extent, that heavy metals will be enhanced solubilized, mobilized and removed together with the seepage water. Batch experiments in order to extract heavy metals from typical soil components (bentonite, peat) by amino acids demonstrate, that removal rates up to 95% can be obtained. (orig.) [de

Agent-based financial dynamics model from stochastic interacting epidemic system and complexity analysis

International Nuclear Information System (INIS)

Lu, Yunfan; Wang, Jun; Niu, Hongli

2015-01-01

An agent-based financial stock price model is developed and investigated by a stochastic interacting epidemic system, which is one of the statistical physics systems and has been used to model the spread of an epidemic or a forest fire. Numerical and statistical analysis are performed on the simulated returns of the proposed financial model. Complexity properties of the financial time series are explored by calculating the correlation dimension and using the modified multiscale entropy method. In order to verify the rationality of the financial model, the real stock market indexes, Shanghai Composite Index and Shenzhen Component Index, are studied in comparison with the simulation data of the proposed model for the different infectiousness parameters. The empirical research reveals that this financial model can reproduce some important features of the real stock markets. - Highlights: • A new agent-based financial price model is developed by stochastic interacting epidemic system. • The structure of the proposed model allows to simulate the financial dynamics. • Correlation dimension and MMSE are applied to complexity analysis of financial time series. • Empirical results show the rationality of the proposed financial model

Agent-based financial dynamics model from stochastic interacting epidemic system and complexity analysis

Energy Technology Data Exchange (ETDEWEB)

Lu, Yunfan, E-mail: yunfanlu@yeah.net; Wang, Jun; Niu, Hongli

2015-06-12

An agent-based financial stock price model is developed and investigated by a stochastic interacting epidemic system, which is one of the statistical physics systems and has been used to model the spread of an epidemic or a forest fire. Numerical and statistical analysis are performed on the simulated returns of the proposed financial model. Complexity properties of the financial time series are explored by calculating the correlation dimension and using the modified multiscale entropy method. In order to verify the rationality of the financial model, the real stock market indexes, Shanghai Composite Index and Shenzhen Component Index, are studied in comparison with the simulation data of the proposed model for the different infectiousness parameters. The empirical research reveals that this financial model can reproduce some important features of the real stock markets. - Highlights: • A new agent-based financial price model is developed by stochastic interacting epidemic system. • The structure of the proposed model allows to simulate the financial dynamics. • Correlation dimension and MMSE are applied to complexity analysis of financial time series. • Empirical results show the rationality of the proposed financial model.

Nonlinear complexity behaviors of agent-based 3D Potts financial dynamics with random environments

Science.gov (United States)

Xing, Yani; Wang, Jun

2018-02-01

A new microscopic 3D Potts interaction financial price model is established in this work, to investigate the nonlinear complexity behaviors of stock markets. 3D Potts model, which extends the 2D Potts model to three-dimensional, is a cubic lattice model to explain the interaction behavior among the agents. In order to explore the complexity of real financial markets and the 3D Potts financial model, a new random coarse-grained Lempel-Ziv complexity is proposed to certain series, such as the price returns, the price volatilities, and the random time d-returns. Then the composite multiscale entropy (CMSE) method is applied to the intrinsic mode functions (IMFs) and the corresponding shuffled data to study the complexity behaviors. The empirical results indicate that the 3D financial model is feasible.

Agent-based model with asymmetric trading and herding for complex financial systems.

Science.gov (United States)

Chen, Jun-Jie; Zheng, Bo; Tan, Lei

2013-01-01

For complex financial systems, the negative and positive return-volatility correlations, i.e., the so-called leverage and anti-leverage effects, are particularly important for the understanding of the price dynamics. However, the microscopic origination of the leverage and anti-leverage effects is still not understood, and how to produce these effects in agent-based modeling remains open. On the other hand, in constructing microscopic models, it is a promising conception to determine model parameters from empirical data rather than from statistical fitting of the results. To study the microscopic origination of the return-volatility correlation in financial systems, we take into account the individual and collective behaviors of investors in real markets, and construct an agent-based model. The agents are linked with each other and trade in groups, and particularly, two novel microscopic mechanisms, i.e., investors' asymmetric trading and herding in bull and bear markets, are introduced. Further, we propose effective methods to determine the key parameters in our model from historical market data. With the model parameters determined for six representative stock-market indices in the world, respectively, we obtain the corresponding leverage or anti-leverage effect from the simulation, and the effect is in agreement with the empirical one on amplitude and duration. At the same time, our model produces other features of the real markets, such as the fat-tail distribution of returns and the long-term correlation of volatilities. We reveal that for the leverage and anti-leverage effects, both the investors' asymmetric trading and herding are essential generation mechanisms. Among the six markets, however, the investors' trading is approximately symmetric for the five markets which exhibit the leverage effect, thus contributing very little. These two microscopic mechanisms and the methods for the determination of the key parameters can be applied to other complex

Rates of nickel(II) capture from complexes with NTA, EDDA, and related tetradentate chelating agents by the hexadentate chelating agents EDTA and CDTA: Evidence of a "semijunctive" ligand exchange pathway

Science.gov (United States)

Boland, Nathan E.; Stone, Alan T.

2017-09-01

Many siderophores and metallophores produced by soil organisms, as well as anthropogenic chelating agent soil amendments, rely upon amine and carboxylate Lewis base groups for metal ion binding. UV-visible spectra of metal ion-chelating agent complexes are often similar and, as a consequence, whole-sample absorbance measurements are an unreliable means of monitoring the progress of exchange reactions. In the present work, we employ capillary electrophoresis to physically separate Ni(II)-tetradentate chelating agent complexes (NiL) from Ni(II)-hexadentate chelating agent complexes (NiY) prior to UV detection, such that progress of the reaction NiL + Y → NiY + L can be conveniently monitored. Rates of ligand exchange for Ni(II) are lower than for other +II transition metal ions. Ni(II) speciation in environmental media is often under kinetic rather than equilibrium control. Nitrilotriacetic acid (NTA), with three carboxylate groups all tethered to a central amine Lewis base group, ethylenediamine-N,N‧-diacetic acid (EDDA), with carboxylate-amine-amine-carboxylate groups arranged linearly, plus four structurally related compounds, are used as tetradentate chelating agents. Ethylenediaminetetraacetic acid (EDTA) and the structurally more rigid analog trans-cyclohexaneethylenediaminetetraacetic acid (CDTA) are used as hexadentate chelating agents. Effects of pH and reactant concentration are explored. Ni(II) capture by EDTA was consistently more than an order of magnitude faster than capture by CDTA, and too fast to quantify using our capillary electrophoresis-based technique. Using NiNTA as a reactant, Ni(II) capture by CDTA is independent of CDTA concentration and greatly enhanced by a proton-catalyzed pathway at low pH. Using NiEDDA as reactant, Ni(II) capture by CDTA is first order with respect to CDTA concentration, and the contribution from the proton-catalyzed pathway diminished by CDTA protonation. While the convention is to assign either a disjunctive

Geochemical behaviour of palladium in soils and Pd/PdO model substances in the presence of the organic complexing agents L-methionine and citric acid.

Science.gov (United States)

Zereini, Fathi; Wiseman, Clare L S; Vang, My; Albers, Peter; Schneider, Wolfgang; Schindl, Roland; Leopold, Kerstin

2016-01-01

Risk assessments of platinum group metal (PGE) emissions, notably those of platinum (Pt), palladium (Pd) and rhodium (Rh), have been mostly based on data regarding the metallic forms used in vehicular exhaust converters, known to be virtually biologically inert and immobile. To adequately assess the potential impacts of PGE, however, data on the chemical behaviour of these metals under ambient conditions post-emission is needed. Complexing agents with a high affinity for metals in the environment are hypothesized to contribute to an increased bioaccessibility of PGE. The purpose of this study is to examine the modulating effects of the organic complexing agents, L-methionine and citric acid, on the geochemical behavior of Pd in soils and model substances (Pd black and PdO). Batch experimental tests were conducted with soils and model substances to examine the impacts of the concentration of complexing agents, pH and length of extraction period on Pd solubility and its chemical transformation. Particle surface chemistry was examined using X-ray photoelectron spectroscopy (XPS) on samples treated with solutions under various conditions, including low and high O2 levels. Pd was observed to be more soluble in the presence of organic complexing agents, compared to Pt and Rh. Pd in soils was more readily solubilized with organic complexing agents compared to the model substances. After 7 days of extraction, L-methionine (0.1 M) treated soil and Pd black samples, for instance, had mean soluble Pd fractions of 12.4 ± 5.9% and 0.554 ± 0.024%, respectively. Surface chemistry analyses (XPS) confirmed the oxidation of metallic Pd surfaces when treated with organic complexing agents. The type of organic complexing agent used for experimental purposes was observed to be the most important factor influencing solubility, followed by solution pH and time of extraction. The results demonstrate that metallic Pd can be transformed into more bioaccessible species in the presence of

Decision Making in Complex Systems The DeciMaS Agent-based Interdisciplinary Framework Approach

CERN Document Server

Sokolova, Marina V

2012-01-01

The study of complex systems attracts the attention of many researchers in diverse fields. Complex systems are characterized by a high number of entities and a high degree of interactions. One of the most important features is that they do not involve a central organizing authority, but the various elements that make up the systems are self-organized. Moreover, some complex systems possess an emergency priority: climate change and sustainable development research, studies of public health, ecosystem habitats, epidemiology, and medicine, among others. Unfortunately, a great number of today’s overlapping approaches fail to meet the needs of decision makers when managing complex domains. Indeed, the design of complex systems often requires the integration of a number of artificial intelligence tools and techniques. The problem can be viewed in terms of goals, states, and actions, choosing the best action to move the system toward its desired state or behavior. This is why agent-based approaches are used to mod...

Influence of complexing agents on the mechanical performances of the cement conditioning matrix

International Nuclear Information System (INIS)

Nicu, M.; Mihai, F.; Turcanu, C.

1998-01-01

The safety of the radioactive waste disposal is a priority demand concerning the protection of the environment and population. For this reason, an engineering multi-barrier system is studied in order to be improved. This study aims to establish the influence of the complexing agents on the mechanical performances of the cement conditioning matrix. Radioactive effluents which contain agents as oxalic and citric acids are generated during the radioactive decontamination operation using chemical methods. The conditioning of these wastes by cementing process imposed the experimental determination of the mechanical performances of the matrix and the upper permissible level of complexing agent concentration. To determine the influence of complexing agents on the mechanical performances of cement conditioning matrix, cubic samples (20 mm x 20 mm x 20 mm) were prepared using commercial Portland cement and solutions of organic complexing acids or salts (citric acid, oxalic acid, tartaric acid, sodium citrate and ammonium oxalate). The complexation concentration varied between 0.25% and 1% in distilled and drinking water, respectively. The selected cement/water ratio was 0.5. The experiments were focused on: - establishing the firmness of the Pa 35 cement pastes and mortars in dependence on the water/cement ratio, by classical methods (Tetmeyer probe for pastes and standard cone for mortars) and by triclinic time through a funnel with 15 mm aperture; - studying the influence of the tartaric, oxalic, citric acids, ammonium oxalate and sodium citrate solution concentrations on water quantities used to obtain pastes with normal firmness and on Pa 35 cement setting; - the influence of oxalic acid, tartaric acid and ammonium oxalate solution concentrations on the strength of compression of the pastes with normal firmness; - for testing, standard test bar cubes with 20 mm sides were used and the strength of compression was tested at 28 days; - establishing the behaviour in time of

Organoruthenium Complexes with CN Ligands are Highly Potent Cytotoxic Agents that Act by a New Mechanism of Action

Czech Academy of Sciences Publication Activity Database

Novohradský, Vojtěch; Yellol, J.; Stuchlíková, O.; Santana, M.D.; Kostrhunová, Hana; Yellol, G.; Kašpárková, Jana; Bautista, D.; Ruiz, J.; Brabec, Viktor

2017-01-01

Roč. 23, č. 61 (2017), s. 15294-15299 ISSN 0947-6539 R&D Projects: GA ČR(CZ) GA17-05302S Institutional support: RVO:68081707 Keywords : chemotherapeutic-agents * ruthenium(ii) complexes * iridium(iii) complexes Subject RIV: CE - Biochemistry OBOR OECD: Biochemistry and molecular biology Impact factor: 5.317, year: 2016

Radiodiagnostic complexes employing fluorine-containing tin reducing agents

International Nuclear Information System (INIS)

Hill, B.K.; Kubik, V.M.

1977-01-01

Radiodiagnostic agents for use in mammalian bodies comprising a radiocomplex which is the reaction product of Tc99m-pertechnetate ion, a diagnostic ligand and a tin (II) reducing agent selected from the group consisting of SnF 2 , MSnF 3 , MSn 2 F 5 and mixtures thereof, wherein M is NH 4 , Na, K, Li, Rb or Cs. Radiocomplex precursor compositions and methods of making the radiocomplex and radiodiagnostic agents are described

Selective transport of metal ions through cation exchange membrane in the presence of a complexing agent

Energy Technology Data Exchange (ETDEWEB)

Tingchia Huang; Jaukai Wang (National Cheng Kung Univ., Tainan (Taiwan, Province of China))

1993-01-01

Selective transport of metal ions through a cation exchange membrane was studied in stirred batch dialyzer for the systems Ni[sup 2+]-Cu[sup 2+] and Cu[sup 2+]-Fe[sup 3+]. Oxalic acid, malonic acid, citric acid, glycine, and ethylenediaminetetraacetic acid were employed as the complexing agents added in the feed solution in order to increase the permselectivity of metal ions. The experimental results show that the selective transport behavior of metal ions depends on the valence and the concentration of metal ions, the stoichiometric ratio of complexing agent to metal ions, and the pH value of the feed solution, but is independent of the concentration of counterion in the stripping phase. A theoretical approach was formulated on the basis of the Nernst-Planck equation and interface quasi-equilibrium. Theoretical solutions obtained from numerical calculation were in agreement with the experimental data.

Automation of multi-agent control for complex dynamic systems in heterogeneous computational network

Science.gov (United States)

Oparin, Gennady; Feoktistov, Alexander; Bogdanova, Vera; Sidorov, Ivan

2017-01-01

The rapid progress of high-performance computing entails new challenges related to solving large scientific problems for various subject domains in a heterogeneous distributed computing environment (e.g., a network, Grid system, or Cloud infrastructure). The specialists in the field of parallel and distributed computing give the special attention to a scalability of applications for problem solving. An effective management of the scalable application in the heterogeneous distributed computing environment is still a non-trivial issue. Control systems that operate in networks, especially relate to this issue. We propose a new approach to the multi-agent management for the scalable applications in the heterogeneous computational network. The fundamentals of our approach are the integrated use of conceptual programming, simulation modeling, network monitoring, multi-agent management, and service-oriented programming. We developed a special framework for an automation of the problem solving. Advantages of the proposed approach are demonstrated on the parametric synthesis example of the static linear regulator for complex dynamic systems. Benefits of the scalable application for solving this problem include automation of the multi-agent control for the systems in a parallel mode with various degrees of its detailed elaboration.

Agent-based model with asymmetric trading and herding for complex financial systems.

Directory of Open Access Journals (Sweden)

Jun-Jie Chen

Full Text Available BACKGROUND: For complex financial systems, the negative and positive return-volatility correlations, i.e., the so-called leverage and anti-leverage effects, are particularly important for the understanding of the price dynamics. However, the microscopic origination of the leverage and anti-leverage effects is still not understood, and how to produce these effects in agent-based modeling remains open. On the other hand, in constructing microscopic models, it is a promising conception to determine model parameters from empirical data rather than from statistical fitting of the results. METHODS: To study the microscopic origination of the return-volatility correlation in financial systems, we take into account the individual and collective behaviors of investors in real markets, and construct an agent-based model. The agents are linked with each other and trade in groups, and particularly, two novel microscopic mechanisms, i.e., investors' asymmetric trading and herding in bull and bear markets, are introduced. Further, we propose effective methods to determine the key parameters in our model from historical market data. RESULTS: With the model parameters determined for six representative stock-market indices in the world, respectively, we obtain the corresponding leverage or anti-leverage effect from the simulation, and the effect is in agreement with the empirical one on amplitude and duration. At the same time, our model produces other features of the real markets, such as the fat-tail distribution of returns and the long-term correlation of volatilities. CONCLUSIONS: We reveal that for the leverage and anti-leverage effects, both the investors' asymmetric trading and herding are essential generation mechanisms. Among the six markets, however, the investors' trading is approximately symmetric for the five markets which exhibit the leverage effect, thus contributing very little. These two microscopic mechanisms and the methods for the

A Composite Agent Architecture for Multi-Agent Simulations

OpenAIRE

VanPutte, Michael; Osborn, Brian; Hiles, John

2002-01-01

CGF Computer Generated Forces and Behavioral Representation The MOVES Institute’s Computer-Generated Autonomy Group has focused on a research goal of modeling complex and adaptive behavior while at the same time making the behavior easier to create and control. This research has led to several techniques for agent construction, that includes a social and organization relationship management engine, a composite agent architecture, an agent goal apparatus, a structure for capturi...

Agent-based model with multi-level herding for complex financial systems

Science.gov (United States)

Chen, Jun-Jie; Tan, Lei; Zheng, Bo

2015-02-01

In complex financial systems, the sector structure and volatility clustering are respectively important features of the spatial and temporal correlations. However, the microscopic generation mechanism of the sector structure is not yet understood. Especially, how to produce these two features in one model remains challenging. We introduce a novel interaction mechanism, i.e., the multi-level herding, in constructing an agent-based model to investigate the sector structure combined with volatility clustering. According to the previous market performance, agents trade in groups, and their herding behavior comprises the herding at stock, sector and market levels. Further, we propose methods to determine the key model parameters from historical market data, rather than from statistical fitting of the results. From the simulation, we obtain the sector structure and volatility clustering, as well as the eigenvalue distribution of the cross-correlation matrix, for the New York and Hong Kong stock exchanges. These properties are in agreement with the empirical ones. Our results quantitatively reveal that the multi-level herding is the microscopic generation mechanism of the sector structure, and provide new insight into the spatio-temporal interactions in financial systems at the microscopic level.

Agent planning in AgScala

Science.gov (United States)

Tošić, Saša; Mitrović, Dejan; Ivanović, Mirjana

2013-10-01

Agent-oriented programming languages are designed to simplify the development of software agents, especially those that exhibit complex, intelligent behavior. This paper presents recent improvements of AgScala, an agent-oriented programming language based on Scala. AgScala includes declarative constructs for managing beliefs, actions and goals of intelligent agents. Combined with object-oriented and functional programming paradigms offered by Scala, it aims to be an efficient framework for developing both purely reactive, and more complex, deliberate agents. Instead of the Prolog back-end used initially, the new version of AgScala relies on Agent Planning Package, a more advanced system for automated planning and reasoning.

Role of bulking agents in bladder exstrophyepispadias complexes ...

African Journals Online (AJOL)

Background: Role of pelvic osteotomy in surgical management of bladder exstrophy is controversial But pelvic rim closure importantly. Bulking agents have been used for perineal and pelvic dysfunction in adults. In this study, bladder extrophy repair was performed without pubic closure And bulking agent injections were ...

Interacting agents in finance

NARCIS (Netherlands)

Hommes, C.; Durlauf, S.N.; Blume, L.E.

2008-01-01

Interacting agents in finance represent a behavioural, agent-based approach in which financial markets are viewed as complex adaptive systems consisting of many boundedly rational agents interacting through simple heterogeneous investment strategies, constantly adapting their behaviour in response

Project SAFE. Complexing agents in SFR

Energy Technology Data Exchange (ETDEWEB)

Fanger, G.; Skagius, K.; Wiborgh, M. [Kemakta Konsult AB, Stockholm (Sweden)

2001-01-01

number (56) of waste packages of waste type S.09. The presence of cellulose based additives in cement used as backfill was evaluated. Calculations resulted in a concentration of ISA below critical levels. For the waste types in BLA the presence of complexing agents has not been studied as no credit is given in the safety assessment to sorption in this repository part (no cement/concrete). The performed calculations have shown that, due to the presence of ISA and other complexants in SFR, a reduction in sorption may have to be applied for some elements in certain waste types when carrying out calculations of the radionuclide transport (the number of waste types depends on assumptions regarding the ISA yield). It should be pointed out that the estimates of concentrations in different waste types are based on a number of conservative assumptions, thus the actual concentrations are probably lower than the calculated.

Project SAFE. Complexing agents in SFR

International Nuclear Information System (INIS)

Fanger, G.; Skagius, K.; Wiborgh, M.

2001-01-01

number (56) of waste packages of waste type S.09. The presence of cellulose based additives in cement used as backfill was evaluated. Calculations resulted in a concentration of ISA below critical levels. For the waste types in BLA the presence of complexing agents has not been studied as no credit is given in the safety assessment to sorption in this repository part (no cement/concrete). The performed calculations have shown that, due to the presence of ISA and other complexants in SFR, a reduction in sorption may have to be applied for some elements in certain waste types when carrying out calculations of the radionuclide transport (the number of waste types depends on assumptions regarding the ISA yield). It should be pointed out that the estimates of concentrations in different waste types are based on a number of conservative assumptions, thus the actual concentrations are probably lower than the calculated

Gd(III) complexes with tripodal pyridine carboxylate ligands: application to optimized contrast agents for NMR Imaging; Complexes de Gd(III) avec des ligands tripodes pyridinocarboxylate: vers des agents de contraste optimises pour l'IRM

Energy Technology Data Exchange (ETDEWEB)

Nonat, A.; Gateau, Ch.; Mallanti, M.; Fries, P. [CEA Grenoble, Dept. de Recherche Fondamentale sur la Matiere Condensee (DRFMC/SCIB/LAI) Lab. de Reconnaissance Ionique, 38 (France)

2005-07-01

In order to better understand the influence of the pyridine carboxylate units on the stability and the electronic relaxation time, and with the aim to obtain gadolinium complexes leading to next generation contrast agents having very high relaxivity, the octadente analogous of the tpatcn which has a water molecule bound in the first coordination sphere has been studied. Here is presented the synthesis, the structural studies, the thermodynamic and relaxometric properties of the Ln(III) complexes of this new tripodal compound 1-carboxy-methyl-4,7-bis[(6-carboxy-pyridin-2-yl)methyl] - 1,4,7-tri-aza-cyclo-nonane. (O.M.)

Porphyrin-containing polyaspartamide gadolinium complexes as potential magnetic resonance imaging contrast agents.

Science.gov (United States)

Yan, Guo-Ping; Li, Zhen; Xu, Wei; Zhou, Cheng-Kai; Yang, Lian; Zhang, Qiao; Li, Liang; Liu, Fan; Han, Lin; Ge, Yuan-Xing; Guo, Jun-Fang

2011-04-04

Porphyrin-containing polyaspartamide ligands (APTSPP-PHEA-DTPA) were synthesized by the incorporation of diethylenetriaminepentaacetic acid (DTPA) and 5-(4'-aminophenyl)-10,15,20-tris(4'-sulfonatophenyl) porphyrin, trisodium salt (APTSPP) into poly-α,β-[N-(2-hydroxyethyl)-l-aspartamide] (PHEA). These ligands were further reacted with gadolinium chloride to produce macromolecule-gadolinium complexes (APTSPP-PHEA-DTPA-Gd). Experimental data of (1)H NMR, IR, UV and elemental analysis evidenced the formation of the polyaspartamide ligands and gadolinium complexes. In vitro and in vivo property tests indicated that APTSPP-PHEA-DTPA-Gd possessed noticeably higher relaxation effectiveness, less toxicity to HeLa cells, and significantly higher enhanced signal intensities (SI) of the VX2 carcinoma in rabbits with lower injection dose requirement than that of Gd-DTPA. Moreover, APTSPP-PHEA-DTPA-Gd was found to greatly enhance the contrast of MR images of the VX2 carcinoma, providing prolonged intravascular duration, and distinguished the VX2 carcinoma and normal tissues in rabbits according to MR image signal enhancements. These porphyrin-containing polyaspartamide gadolinium complexes can be used as the candidates of contrast agents for targeted MRI to tumors. Crown Copyright © 2011. Published by Elsevier B.V. All rights reserved.

Design of a multi-agent hydroeconomic model to simulate a complex human-water system: Early insights from the Jordan Water Project

Science.gov (United States)

Yoon, J.; Klassert, C. J. A.; Lachaut, T.; Selby, P. D.; Knox, S.; Gorelick, S.; Rajsekhar, D.; Tilmant, A.; Avisse, N.; Harou, J. J.; Gawel, E.; Klauer, B.; Mustafa, D.; Talozi, S.; Sigel, K.

2015-12-01

Our work focuses on development of a multi-agent, hydroeconomic model for purposes of water policy evaluation in Jordan. The model adopts a modular approach, integrating biophysical modules that simulate natural and engineered phenomena with human modules that represent behavior at multiple levels of decision making. The hydrologic modules are developed using spatially-distributed groundwater and surface water models, which are translated into compact simulators for efficient integration into the multi-agent model. For the groundwater model, we adopt a response matrix method approach in which a 3-dimensional MODFLOW model of a complex regional groundwater system is converted into a linear simulator of groundwater response by pre-processing drawdown results from several hundred numerical simulation runs. Surface water models for each major surface water basin in the country are developed in SWAT and similarly translated into simple rainfall-runoff functions for integration with the multi-agent model. The approach balances physically-based, spatially-explicit representation of hydrologic systems with the efficiency required for integration into a complex multi-agent model that is computationally amenable to robust scenario analysis. For the multi-agent model, we explicitly represent human agency at multiple levels of decision making, with agents representing riparian, management, supplier, and water user groups. The agents' decision making models incorporate both rule-based heuristics as well as economic optimization. The model is programmed in Python using Pynsim, a generalizable, open-source object-oriented code framework for modeling network-based water resource systems. The Jordan model is one of the first applications of Pynsim to a real-world water management case study. Preliminary results from a tanker market scenario run through year 2050 are presented in which several salient features of the water system are investigated: competition between urban and

Rhodium complexes as therapeutic agents.

Science.gov (United States)

Ma, Dik-Lung; Wang, Modi; Mao, Zhifeng; Yang, Chao; Ng, Chan-Tat; Leung, Chung-Hang

2016-02-21

The landscape of inorganic medicinal chemistry has been dominated by the investigation of platinum, and to a lesser extent ruthenium, complexes over the past few decades. Recently, complexes based on other metal centers such as rhodium have attracted attention due to their tunable chemical and biological properties as well as distinct mechanisms of action. This perspective highlights recent examples of rhodium complexes that show diverse biological activities against various targets, including enzymes and protein-protein interactions.

Study of the leaching of heavy metals from waste water sludge and incinerator's ash, using coupled thermostated columns and DTPA as complex agent

International Nuclear Information System (INIS)

Vite T, J.; Vite T, M.; Guerrero D, J.; Carreno de Leon, M.C.

2000-01-01

We studied the metallic composition from waste water sludge and incinerators ashes of an incinerator located in Toluca, Mexico, the qualitative studies were made using the Activation Analysis technique, and fluorescence X-ray techniques. The quantitative analysis of heavy metals in the wastes were made using Inductively coupled plasma atomic emission spectrometry (Icp-Aes). For leaching the samples, we used four coupled thermostated columns, each one had a p H of 2,5, 7 and 10. The flux of the air was of 1600 cc/min. The temperature was maintain constant in 60 Centigrade using a thermostated system. For this study we used 100 g of wastes mixed with mineral acid or sodium hydroxide to reach p H 2,5,7 and 10. We added a reducing and tensoactive agents and finally DTPA as complex agent. With this method, we obtain a better leaching efficiency using a complex agent. However the high DTPA cost, make this process expansive that is why we recommend to work with another classes of complex agents, that be cheaper to leach metals of different chemistry matrix. (Author)

Chemical warfare agents.

Science.gov (United States)

Kuca, Kamil; Pohanka, Miroslav

2010-01-01

Chemical warfare agents are compounds of different chemical structures. Simple molecules such as chlorine as well as complex structures such as ricin belong to this group. Nerve agents, vesicants, incapacitating agents, blood agents, lung-damaging agents, riot-control agents and several toxins are among chemical warfare agents. Although the use of these compounds is strictly prohibited, the possible misuse by terrorist groups is a reality nowadays. Owing to this fact, knowledge of the basic properties of these substances is of a high importance. This chapter briefly introduces the separate groups of chemical warfare agents together with their members and the potential therapy that should be applied in case someone is intoxicated by these agents.

Agent autonomy approach to probabilistic physics-of-failure modeling of complex dynamic systems with interacting failure mechanisms

Science.gov (United States)

Gromek, Katherine Emily

A novel computational and inference framework of the physics-of-failure (PoF) reliability modeling for complex dynamic systems has been established in this research. The PoF-based reliability models are used to perform a real time simulation of system failure processes, so that the system level reliability modeling would constitute inferences from checking the status of component level reliability at any given time. The "agent autonomy" concept is applied as a solution method for the system-level probabilistic PoF-based (i.e. PPoF-based) modeling. This concept originated from artificial intelligence (AI) as a leading intelligent computational inference in modeling of multi agents systems (MAS). The concept of agent autonomy in the context of reliability modeling was first proposed by M. Azarkhail [1], where a fundamentally new idea of system representation by autonomous intelligent agents for the purpose of reliability modeling was introduced. Contribution of the current work lies in the further development of the agent anatomy concept, particularly the refined agent classification within the scope of the PoF-based system reliability modeling, new approaches to the learning and the autonomy properties of the intelligent agents, and modeling interacting failure mechanisms within the dynamic engineering system. The autonomous property of intelligent agents is defined as agent's ability to self-activate, deactivate or completely redefine their role in the analysis. This property of agents and the ability to model interacting failure mechanisms of the system elements makes the agent autonomy fundamentally different from all existing methods of probabilistic PoF-based reliability modeling. 1. Azarkhail, M., "Agent Autonomy Approach to Physics-Based Reliability Modeling of Structures and Mechanical Systems", PhD thesis, University of Maryland, College Park, 2007.

Carboxylate derivatives of tributyltin (IV) complexes as anticancer and antileishmanial agents.

Science.gov (United States)

Waseem, Durdana; Butt, Arshad Farooq; Haq, Ihsan-Ul; Bhatti, Moazzam Hussain; Khan, Gul Majid

2017-04-04

Tributyltin (IV) compounds are promising candidates for drug development. In the current study, we evaluated in-vitro and in-silico profile of carboxylate derivatives of tributyltin (IV) complexes. ADMET and drug-likeliness properties were predicted using MetaPrint2D React, preADMET, SwissADME and Molsoft tools. SwissTargetPrediction predicted molecular targets for compounds. In-vitro bioactivity was evaluated by quantifying cytotoxicity against HepG2, THP-1 cell lines, isolated lymphocytes and leishmania promastigotes as well as measuring protein kinase (PK) inhibition activity. Results indicate partial compliance of compounds with drug-likeliness rules. Ch-409 complies with WDI and Lipinski rules. ADMET profile prediction shows strong plasma protein binding except for Ch-409, low to high GI absorption and BBB penetration (C brain /C blood  = 0.942-11; caco-2 cells permeability 20.13-26.75 nm/sec), potential efflux by P-glycoprotein, metabolism by CYP3A4, medium inhibition of hERG, mutagenicity and capacity to be detoxified by glutathionation and glucuronidation. Molecular targets include proteases, enzymes, membrane receptors, transporters and ion channels where Ch-409 targets membrane receptors only. Compounds are significantly (p tributyltin (IV) complexes possess significant antileishmanial and cytotoxic potential. These are promising compounds for the development of antileishmanial and anticancer drugs. Graphical Abstract Carboxylate derivatives of tributyltin (IV) complexes as anticancer and antileishmanial agents.

An Agent-Based Optimization Framework for Engineered Complex Adaptive Systems with Application to Demand Response in Electricity Markets

Science.gov (United States)

Haghnevis, Moeed

The main objective of this research is to develop an integrated method to study emergent behavior and consequences of evolution and adaptation in engineered complex adaptive systems (ECASs). A multi-layer conceptual framework and modeling approach including behavioral and structural aspects is provided to describe the structure of a class of engineered complex systems and predict their future adaptive patterns. The approach allows the examination of complexity in the structure and the behavior of components as a result of their connections and in relation to their environment. This research describes and uses the major differences of natural complex adaptive systems (CASs) with artificial/engineered CASs to build a framework and platform for ECAS. While this framework focuses on the critical factors of an engineered system, it also enables one to synthetically employ engineering and mathematical models to analyze and measure complexity in such systems. In this way concepts of complex systems science are adapted to management science and system of systems engineering. In particular an integrated consumer-based optimization and agent-based modeling (ABM) platform is presented that enables managers to predict and partially control patterns of behaviors in ECASs. Demonstrated on the U.S. electricity markets, ABM is integrated with normative and subjective decision behavior recommended by the U.S. Department of Energy (DOE) and Federal Energy Regulatory Commission (FERC). The approach integrates social networks, social science, complexity theory, and diffusion theory. Furthermore, it has unique and significant contribution in exploring and representing concrete managerial insights for ECASs and offering new optimized actions and modeling paradigms in agent-based simulation.

Modelling and Simulating Complex Systems in Biology: introducing NetBioDyn : A Pedagogical and Intuitive Agent-Based Software

OpenAIRE

Ballet, Pascal; Rivière, Jérémy; Pothet, Alain; Théron, Michaël; Pichavant, Karine; Abautret, Frank; Fronville, Alexandra; Rodin, Vincent

2017-01-01

International audience; Modelling and teaching complex biological systems is a difficult process. Multi-Agent Based Simulations (MABS) have proved to be an appropriate approach both in research and education when dealing with such systems including emergent, self-organizing phenomena. This chapter presents NetBioDyn, an original software aimed at biologists (students, teachers, researchers) to easily build and simulate complex biological mechanisms observed in multicellular and molecular syst...

Partition of lead in milk-pectin aqueous biphasic system with complexation agents

International Nuclear Information System (INIS)

Bartos, P.; Macasek, F.; Gerhart, P.

1997-01-01

In present work, decontamination of raw cow milk from lead was investigated using the 'membraneless dialysis'. The 4% w/w solutions of apple pectin, degree of esterification 70%, containing various complexing agents were used for experiments at the initial volume ration pectin : milk = 3:7 which changed to 8:2 at equilibration. Radioactive indicator 212 Pb was prepared from 228 Th emanator. After dissolution in Jennes-Koops buffer with 10 -5 M Pb 2+ carrier, milk was spiked with the indicator for 100 minutes. Distribution equilibrium of water and lead was achieved after next 100 minutes but yield of lead extraction into pectin phase was less then 2.3% in the case of raw milk, and less then 3.0% in the case of pasteurized milk. Due to denaturation of raw milk, there are strongly limited possibilities to influence the radionuclide partition in the systems. Various non-toxic complexation agents (glycine, alanine, histidine, cysteine, Edtacal) were applied to improve extraction of lead to pectin phase. Glycine and histidine have not influence on lead extraction yields but there was observed an increased yield, 3,8% for alanine and even 25% for 0.002 M cysteine. As the most interesting appeared application of Edtacal, calcium salt of ethylenediaminetetraacetic acid, EDTA by which the recovery of lead with with pectin phase reached about 80% at concentration of EDTA in initial pectin phase 0.001 M. The retention of Pb 2+ cation in milk phase is extraordinary high as compared with strontium and corresponds to behavior of trivalent ions what is attributed to specific interactions with thiol groups of milk components

Evaluation of the Sensititre MycoTB plate for susceptibility testing of the Mycobacterium tuberculosis complex against first- and second-line agents.

Science.gov (United States)

Hall, Leslie; Jude, Kurt P; Clark, Shirley L; Dionne, Kim; Merson, Ryan; Boyer, Ana; Parrish, Nicole M; Wengenack, Nancy L

2012-11-01

The Sensititre MycoTB plate (TREK Diagnostic Systems, Cleveland, OH) uses a microtiter plate MIC format for susceptibility testing of Mycobacterium tuberculosis complex isolates against first- and second-line antituberculosis agents. Categorical agreement versus the agar proportion method for 122 M. tuberculosis complex isolates was 94% to 100%.

Distributed optimization-based control of multi-agent networks in complex environments

CERN Document Server

Zhu, Minghui

2015-01-01

This book offers a concise and in-depth exposition of specific algorithmic solutions for distributed optimization based control of multi-agent networks and their performance analysis. It synthesizes and analyzes distributed strategies for three collaborative tasks: distributed cooperative optimization, mobile sensor deployment and multi-vehicle formation control. The book integrates miscellaneous ideas and tools from dynamic systems, control theory, graph theory, optimization, game theory and Markov chains to address the particular challenges introduced by such complexities in the environment as topological dynamics, environmental uncertainties, and potential cyber-attack by human adversaries. The book is written for first- or second-year graduate students in a variety of engineering disciplines, including control, robotics, decision-making, optimization and algorithms and with backgrounds in aerospace engineering, computer science, electrical engineering, mechanical engineering and operations research. Resea...

Preparation and evaluation of a radiogallium complex-conjugated bisphosphonate as a bone scintigraphy agent

International Nuclear Information System (INIS)

Ogawa, Kazuma; Takai, Kenichiro; Kanbara, Hiroya; Kiwada, Tatsuto; Kitamura, Yoji; Shiba, Kazuhiro; Odani, Akira

2011-01-01

Introduction: 68 Ga is a radionuclide of great interest as a positron emitter for positron emission tomography (PET). To develop a new bone-imaging agent with radiogallium, 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid (DOTA) was chosen as a chelating site and Ga-DOTA complex-conjugated bisphosphonate, which has a high affinity for bone, was prepared and evaluated. Although we are interested in developing 68 Ga-labeled bone imaging agents for PET, in these initial studies 67 Ga was used because of its longer half-life. Methods: DOTA-conjugated bisphosphonate (DOTA-Bn-SCN-HBP) was synthesized by conjugation of 2-(4-isothiocyanatebenzyl)-1,4,7,10-tetraazacyclododecane-1,4,7, 10-tetraacetic acid to 4-amino-1-hydroxybutylidene-1,1-bisphosphonate (alendronate). 67 Ga-DOTA-Bn-SCN-HBP was prepared by coordination with 67 Ga, and its in vitro and in vivo evaluations were performed. Results: 67 Ga-DOTA-Bn-SCN-HBP was prepared with a radiochemical purity of over 95% without purification. 67 Ga-DOTA-Bn-SCN-HBP had great affinity for hydroxyapatite in binding assay. In biodistribution experiments, 67 Ga-DOTA-Bn-SCN-HBP accumulated in bone rapidly but was hardly observed in tissues other than bone. Pretreatment of an excess amount of alendronate inhibited the bone accumulation of 67 Ga-DOTA-Bn-SCN-HBP. Conclusions: 67 Ga-DOTA-Bn-SCN-HBP showed ideal biodistribution characteristics as a bone-imaging agent. These findings should provide useful information on the drug design of bone imaging agents for PET with 68 Ga.

Gadolinium(III-DOTA Complex Functionalized with BODIPY as a Potential Bimodal Contrast Agent for MRI and Optical Imaging

Directory of Open Access Journals (Sweden)

Matthias Ceulemans

2015-11-01

Full Text Available The synthesis and characterization of a novel gadolinium(III DOTA complex functionalized with a boron-dipyrromethene derivative (BODIPY is described. The assembly of the complex relies on azide diazotransfer chemistry in a copper tube flow reactor. The azide thus formed is coupled directly with an alkyne via click chemistry, resulting into a paramagnetic and luminescent gadolinium(III complex. Luminescent data and relaxometric properties of the complex have been evaluated, suggesting the potential applicability of the complexes as a bimodal contrast agent for magnetic resonance and optical imaging. The complex displays a bright emission at 523 nm with an absorption maximum of 507 nm and high quantum yields of up to 83% in water. The proton relaxivity of the complex measured at 310 K and at frequencies of 20 and 60 MHz had the values of 3.9 and 3.6 s−1·mM−1, respectively.

Simple boron removal from seawater by using polyols as complexing agents: A computational mechanistic study

Energy Technology Data Exchange (ETDEWEB)

Kim, Min-Kyung; Eom, Ki Heon; Lim, Jun-Heok; Lee, Jea-Keun; Lee, Ju Dong; Won, Yong Sun [Pukyong National University, Busan (Korea, Republic of)

2015-11-15

The complexation of boric acid (B(OH){sub 3}), the primary form of aqueous boron at moderate pH, with polyols is proposed and mechanistically studied as an efficient way to improve membrane processes such as reverse osmosis (RO) for removing boron in seawater by increasing the size of aqueous boron compounds. Computational chemistry based on the density functional theory (DFT) was used to manifest the reaction pathways of the complexation of B(OH){sub 3} with various polyols such as glycerol, xylitol, and mannitol. The reaction energies were calculated as −80.6, −98.1, and −87.2 kcal/mol for glycerol, xylitol, and mannitol, respectively, indicating that xylitol is the most thermodynamically favorable for the complexation with B(OH){sub 3}. Moreover, the 1 : 2 molar ratio of B(OH)3 to polyol was found to be more favorable than the ratio of 1 : 1 for the complexation. Meanwhile, latest lab-scale actual RO experiments successfully supported our computational prediction that 2 moles of xylitol are the most effective as the complexing agent for 1 mole of B(OH){sub 3} in aqueous solution.

Towards Agent-Based Model Specification in Smart Grid: A Cognitive Agent-based Computing Approach

OpenAIRE

Akram, Waseem; Niazi, Muaz A.; Iantovics, Laszlo Barna

2017-01-01

A smart grid can be considered as a complex network where each node represents a generation unit or a consumer. Whereas links can be used to represent transmission lines. One way to study complex systems is by using the agent-based modeling (ABM) paradigm. An ABM is a way of representing a complex system of autonomous agents interacting with each other. Previously, a number of studies have been presented in the smart grid domain making use of the ABM paradigm. However, to the best of our know...

Complexity in Simplicity: Flexible Agent-based State Space Exploration

DEFF Research Database (Denmark)

Rasmussen, Jacob Illum; Larsen, Kim Guldstrand

2007-01-01

In this paper, we describe a new flexible framework for state space exploration based on cooperating agents. The idea is to let various agents with different search patterns explore the state space individually and communicate information about fruitful subpaths of the search tree to each other...

Neuroprotective "agents" in surgery. Secret "agent" man, or common "agent" machine?

Science.gov (United States)

Andrews, R. J.

1999-01-01

The search for clinically-effective neuroprotective agents has received enormous support in recent years--an estimated $200 million by pharmaceutical companies on clinical trials for traumatic brain injury alone. At the same time, the pathophysiology of brain injury has proved increasingly complex, rendering the likelihood of a single agent "magic bullet" even more remote. On the other hand, great progress continues with technology that makes surgery less invasive and less risky. One example is the application of endovascular techniques to treat coronary artery stenosis, where both the invasiveness of sternotomy and the significant neurological complication rate (due to microemboli showering the cerebral vasculature) can be eliminated. In this paper we review aspects of intraoperative neuroprotection both present and future. Explanations for the slow progress on pharmacologic neuroprotection during surgery are presented. Examples of technical advances that have had great impact on neuroprotection during surgery are given both from coronary artery stenosis surgery and from surgery for Parkinson's disease. To date, the progress in neuroprotection resulting from such technical advances is an order of magnitude greater than that resulting from pharmacologic agents used during surgery. The progress over the last 20 years in guidance during surgery (CT and MRI image-guidance) and in surgical access (endoscopic and endovascular techniques) will soon be complemented by advances in our ability to evaluate biological tissue intraoperatively in real-time. As an example of such technology, the NASA Smart Probe project is considered. In the long run (i.e., in 10 years or more), pharmacologic "agents" aimed at the complex pathophysiology of nervous system injury in man will be the key to true intraoperative neuroprotection. In the near term, however, it is more likely that mundane "agents" based on computers, microsensors, and microeffectors will be the major impetus to improved

Method of purifying uranium tetrafluoride hydrate and preparing uranium (VI) peroxide hydrate using a fluoride complexing agent

International Nuclear Information System (INIS)

Barreiro, A.J.; Lowe, C.M.T.; Lefever, J.A.; Pyman, R.L.

1983-01-01

The annual production of phosphate rock, on the order of about 30-40 million tons yearly, represents several million pounds of uranium. The present invention provides a process of purifying uranium tetrafluoride hydrate to produce a uranium (VI) peroxide product meeting 'yellow cake' standards using a double precipitation procedure. A fluoride complexing agent is used in the precipitation

The highly intelligent virtual agents for modeling financial markets

Science.gov (United States)

Yang, G.; Chen, Y.; Huang, J. P.

2016-02-01

Researchers have borrowed many theories from statistical physics, like ensemble, Ising model, etc., to study complex adaptive systems through agent-based modeling. However, one fundamental difference between entities (such as spins) in physics and micro-units in complex adaptive systems is that the latter are usually with high intelligence, such as investors in financial markets. Although highly intelligent virtual agents are essential for agent-based modeling to play a full role in the study of complex adaptive systems, how to create such agents is still an open question. Hence, we propose three principles for designing high artificial intelligence in financial markets and then build a specific class of agents called iAgents based on these three principles. Finally, we evaluate the intelligence of iAgents through virtual index trading in two different stock markets. For comparison, we also include three other types of agents in this contest, namely, random traders, agents from the wealth game (modified on the famous minority game), and agents from an upgraded wealth game. As a result, iAgents perform the best, which gives a well support for the three principles. This work offers a general framework for the further development of agent-based modeling for various kinds of complex adaptive systems.

[Alkylating agents].

Science.gov (United States)

Pourquier, Philippe

2011-11-01

With the approval of mechlorethamine by the FDA in 1949 for the treatment of hematologic malignancies, alkylating agents are the oldest class of anticancer agents. Even though their clinical use is far beyond the use of new targeted therapies, they still occupy a major place in specific indications and sometimes represent the unique option for the treatment of refractory diseases. Here, we are reviewing the major classes of alkylating agents and their mechanism of action, with a particular emphasis for the new generations of alkylating agents. As for most of the chemotherapeutic agents used in the clinic, these compounds are derived from natural sources. With a complex but original mechanism of action, they represent new interesting alternatives for the clinicians, especially for tumors that are resistant to conventional DNA damaging agents. We also briefly describe the different strategies that have been or are currently developed to potentiate the use of classical alkylating agents, especially the inhibition of pathways that are involved in the repair of DNA lesions induced by these agents. In this line, the development of PARP inhibitors is a striking example of the recent regain of interest towards the "old" alkylating agents.

Preparation and evaluation of a radiogallium complex-conjugated bisphosphonate as a bone scintigraphy agent

Energy Technology Data Exchange (ETDEWEB)

Ogawa, Kazuma, E-mail: kogawa@p.kanazawa-u.ac.jp [Graduate School of Natural Science and Technology, Kanazawa University, Kanazawa 920-1192 (Japan); Takai, Kenichiro; Kanbara, Hiroya; Kiwada, Tatsuto [Graduate School of Natural Science and Technology, Kanazawa University, Kanazawa 920-1192 (Japan); Kitamura, Yoji; Shiba, Kazuhiro [Advanced Science Research Center, Kanazawa University, Kanazawa 920-8640 (Japan); Odani, Akira [Graduate School of Natural Science and Technology, Kanazawa University, Kanazawa 920-1192 (Japan)

2011-07-15

Introduction: {sup 68}Ga is a radionuclide of great interest as a positron emitter for positron emission tomography (PET). To develop a new bone-imaging agent with radiogallium, 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid (DOTA) was chosen as a chelating site and Ga-DOTA complex-conjugated bisphosphonate, which has a high affinity for bone, was prepared and evaluated. Although we are interested in developing {sup 68}Ga-labeled bone imaging agents for PET, in these initial studies {sup 67}Ga was used because of its longer half-life. Methods: DOTA-conjugated bisphosphonate (DOTA-Bn-SCN-HBP) was synthesized by conjugation of 2-(4-isothiocyanatebenzyl)-1,4,7,10-tetraazacyclododecane-1,4,7, 10-tetraacetic acid to 4-amino-1-hydroxybutylidene-1,1-bisphosphonate (alendronate). {sup 67}Ga-DOTA-Bn-SCN-HBP was prepared by coordination with {sup 67}Ga, and its in vitro and in vivo evaluations were performed. Results: {sup 67}Ga-DOTA-Bn-SCN-HBP was prepared with a radiochemical purity of over 95% without purification. {sup 67}Ga-DOTA-Bn-SCN-HBP had great affinity for hydroxyapatite in binding assay. In biodistribution experiments, {sup 67}Ga-DOTA-Bn-SCN-HBP accumulated in bone rapidly but was hardly observed in tissues other than bone. Pretreatment of an excess amount of alendronate inhibited the bone accumulation of {sup 67}Ga-DOTA-Bn-SCN-HBP. Conclusions: {sup 67}Ga-DOTA-Bn-SCN-HBP showed ideal biodistribution characteristics as a bone-imaging agent. These findings should provide useful information on the drug design of bone imaging agents for PET with {sup 68}Ga.

Fairness in multi-agent systems

NARCIS (Netherlands)

Jong, de S.; Tuyls, K.P.; Verbeeck, K.

2008-01-01

Multi-agent systems are complex systems in which multiple autonomous entities, called agents, cooperate in order to achieve a common or personal goal. These entities may be computer software, robots, and also humans. In fact, many multi-agent systems are intended to operate in cooperation with or as

Multi-Agent Systems for E-Commerce

OpenAIRE

Solodukha, T. V.; Sosnovskiy, O. A.; Zhelezko, B. A.

2009-01-01

The article focuses on multi-agent systems (MAS) and domains that can benefit from multi-agent technology. In the last few years, the agent based modeling (ABM) community has developed several practical agent based modeling toolkits that enable individuals to develop agent-based applications. The comparison of agent-based modeling toolkits is given. Multi-agent systems are designed to handle changing and dynamic business processes. Any organization with complex and distributed business pro...

Agent-Based Model Approach to Complex Phenomena in Real Economy

Science.gov (United States)

Iyetomi, H.; Aoyama, H.; Fujiwara, Y.; Ikeda, Y.; Souma, W.

An agent-based model for firms' dynamics is developed. The model consists of firm agents with identical characteristic parameters and a bank agent. Dynamics of those agents are described by their balance sheets. Each firm tries to maximize its expected profit with possible risks in market. Infinite growth of a firm directed by the ``profit maximization" principle is suppressed by a concept of ``going concern". Possibility of bankruptcy of firms is also introduced by incorporating a retardation effect of information on firms' decision. The firms, mutually interacting through the monopolistic bank, become heterogeneous in the course of temporal evolution. Statistical properties of firms' dynamics obtained by simulations based on the model are discussed in light of observations in the real economy.

Teamwork in Multi-Agent Systems A Formal Approach

CERN Document Server

Dunin-Keplicz, Barbara Maria

2010-01-01

What makes teamwork tick?. Cooperation matters, in daily life and in complex applications. After all, many tasks need more than a single agent to be effectively performed. Therefore, teamwork rules!. Teams are social groups of agents dedicated to the fulfilment of particular persistent tasks. In modern multiagent environments, heterogeneous teams often consist of autonomous software agents, various types of robots and human beings. Teamwork in Multi-agent Systems: A Formal Approach explains teamwork rules in terms of agents' attitudes and their complex interplay. It provides the first comprehe

Separation of americium by liquid-liquid extraction using diglycol-amides water-soluble complexing agents

Energy Technology Data Exchange (ETDEWEB)

Chapron, S.; Marie, C.; Pacary, V.; Duchesne, M.T.; Miguirditchian, M. [CEA, Centre de Marcoule, Nuclear Energy Division, RadioChemistry and Processses Departement, 30207 Bagnols-sur-Ceze (France); Arrachart, G.; Pellet-Rostaing, S. [Institut de Chimie Separative de Marcoule, LTSM, Bat 426, F-30207 Bagnols-sur- Ceze (France)

2016-07-01

Recycling americium (Am) alone from spent nuclear fuels is an important option studied for the future nuclear cycle (Generation IV systems) since Am belongs to the main contributors of the long-term radiotoxicity and heat power of final waste. Since 2008, a liquid-liquid extraction process called EXAm has been developed by the CEA to allow the recovery of Am alone from a PUREX raffinate (a dissolution solution already cleared from U, Np and Pu). A mixture of DMDOHEMA (N,N'-dimethyl-N,N'-dioctyl-2-(2-(hexyloxy)ethyl)-malonamide) and HDEHP (di-2-ethylhexylphosphoric acid) in TPH is used as the solvent and the Am/Cm selectivity is improved using TEDGA (N,N,N',N'-tetraethyl-diglycolamide) as a selective complexing agent to maintain Cm and heavier lanthanides in the acidic aqueous phase (5 M HNO{sub 3}). Americium is then stripped selectively from light lanthanides at low acidity (pH=3) with a poly-aminocarboxylic acid. The feasibility of sole Am recovery was already demonstrated during hot tests in ATALANTE facility and the EXAm process was adapted to a concentrated raffinate to optimize the process compactness. The speciation of TEDGA complexes formed in the aqueous phase with Am, Cm and lanthanides was studied to better understand and model the behavior of TEDGA in the process. Some Ln-TEDGA species are extracted into the organic phase and this specific chemistry might play a role in the Am/Cm selectivity improvement. Hence the hydrophilicity-lipophilicity balance of the complexing agent is an important parameter. In this comprehensive study, new analogues of TEDGA were synthesized and tested in the EXAm process conditions to understand the relationship between their structure and selectivity. New derivatives of TEDGA with different N-alkyl chain lengths and ramifications were synthesized. The impact of lipophilicity on ligand partitioning and Am/Cm selectivity was investigated. (authors)

The R-Shell approach - Using scheduling agents in complex distributed real-time systems

Science.gov (United States)

Natarajan, Swaminathan; Zhao, Wei; Goforth, Andre

1993-01-01

Large, complex real-time systems such as space and avionics systems are extremely demanding in their scheduling requirements. The current OS design approaches are quite limited in the capabilities they provide for task scheduling. Typically, they simply implement a particular uniprocessor scheduling strategy and do not provide any special support for network scheduling, overload handling, fault tolerance, distributed processing, etc. Our design of the R-Shell real-time environment fcilitates the implementation of a variety of sophisticated but efficient scheduling strategies, including incorporation of all these capabilities. This is accomplished by the use of scheduling agents which reside in the application run-time environment and are responsible for coordinating the scheduling of the application.

The effect of dual complexing agents of lactic and citric acids on the formation of sol-gel derived Ag–PbTiO3 percolative thin film

International Nuclear Information System (INIS)

Su, Yanbo; Hu, Tao; Tang, Liwen; Weng, Wenjian; Han, Gaorong; Ma, Ning; Du, Piyi

2014-01-01

Controlling the formation of conductive particles to be nano-scale is important for achieving percolation effect in metal dispersed thin film composite to contribute extraordinary dielectric properties required for miniaturization of electronic devices. In this paper, lactic acid (LA) and citric acid (CA) were used as dual complexing agents to prepare a typical Ag nanoparticle dispersed PbTiO 3 (PTO) composite thin film by using a sol-gel method. The phase structure of the thin film and the coordination effect between complexing agent and metallic ions were investigated. It revealed that LA coordinated with Ti 4+ and Pb 2+ and CA coordinated with Ag + . Lead was fixed inside the gel network by LA and restricted to evaporate during heat treatment thus the pyrochlore phase was prevented from forming in the thin film. Ag + was coordinated by CA and the diffusion and thus aggregation of silver during gelation and annealing process were weakened. Silver nanoparticles dispersed in the PTO matrix formed with dual complexing agents of LA and CA introduced during the preparation process. The composite thin film of perfect perovskite phase with silver nanoparticles embedded was obtained at the molar ratio of LA/lead = 0.5 and CA/lead = 0.5. The dielectric constant of the thin film with silver nanoparticles is 5 times higher than that without silver nanoparticles. - Highlights: • Ag nanoparticle–PbTiO 3 percolative film with high dielectric property is prepared. • Evaporation of lead was prevented by coordinating Pb with lactic acid agent. • Dual complexing agents contribute block and pinning effects to form Ag nanoparticles

9th KES Conference on Agent and Multi-Agent Systems : Technologies and Applications

CERN Document Server

Howlett, Robert; Jain, Lakhmi

2015-01-01

Agents and multi-agent systems are related to a modern software paradigm which has long been recognized as a promising technology for constructing autonomous, complex and intelligent systems. The topics covered in this volume include agent-oriented software engineering, agent co-operation, co-ordination, negotiation, organization and communication, distributed problem solving, specification of agent communication languages, agent privacy, safety and security, formalization of ontologies and conversational agents. The volume highlights new trends and challenges in agent and multi-agent research and includes 38 papers classified in the following specific topics: learning paradigms, agent-based modeling and simulation, business model innovation and disruptive technologies, anthropic-oriented computing, serious games and business intelligence, design and implementation of intelligent agents and multi-agent systems, digital economy, and advances in networked virtual enterprises. Published p...

How new concepts become universal scientific approaches: insights from citation network analysis of agent-based complex systems science.

Science.gov (United States)

Vincenot, Christian E

2018-03-14

Progress in understanding and managing complex systems comprised of decision-making agents, such as cells, organisms, ecosystems or societies, is-like many scientific endeavours-limited by disciplinary boundaries. These boundaries, however, are moving and can actively be made porous or even disappear. To study this process, I advanced an original bibliometric approach based on network analysis to track and understand the development of the model-based science of agent-based complex systems (ACS). I analysed research citations between the two communities devoted to ACS research, namely agent-based (ABM) and individual-based modelling (IBM). Both terms refer to the same approach, yet the former is preferred in engineering and social sciences, while the latter prevails in natural sciences. This situation provided a unique case study for grasping how a new concept evolves distinctly across scientific domains and how to foster convergence into a universal scientific approach. The present analysis based on novel hetero-citation metrics revealed the historical development of ABM and IBM, confirmed their past disjointedness, and detected their progressive merger. The separation between these synonymous disciplines had silently opposed the free flow of knowledge among ACS practitioners and thereby hindered the transfer of methodological advances and the emergence of general systems theories. A surprisingly small number of key publications sparked the ongoing fusion between ABM and IBM research. Beside reviews raising awareness of broad-spectrum issues, generic protocols for model formulation and boundary-transcending inference strategies were critical means of science integration. Accessible broad-spectrum software similarly contributed to this change. From the modelling viewpoint, the discovery of the unification of ABM and IBM demonstrates that a wide variety of systems substantiate the premise of ACS research that microscale behaviours of agents and system-level dynamics

Modelling and simulation of electrical energy systems through a complex systems approach using agent-based models

Energy Technology Data Exchange (ETDEWEB)

Kremers, Enrique

2013-10-01

Complexity science aims to better understand the processes of both natural and man-made systems which are composed of many interacting entities at different scales. A disaggregated approach is proposed for simulating electricity systems, by using agent-based models coupled to continuous ones. The approach can help in acquiring a better understanding of the operation of the system itself, e.g. on emergent phenomena or scale effects; as well as in the improvement and design of future smart grids.

evaluation of some technetium-99m fluoroquinolones complexes as imaging agents for bacterial inflammatory lesions

International Nuclear Information System (INIS)

Abdel-Kawy, O.A.A.

2007-01-01

in this study, the labeling method of ciprofloxacin and levofloxacin with technetium-99m and their biological evaluation in man-induced inflammation models were described . in -vitro microbiological evaluation of both complexes was also performed in order to investigate the effect of labeling on the activity and spectrum of both antibiotics. all the gathered biological data support the usefulness of 99m Tc-fluoroquinolones as infection imaging agents that could discriminate between infections and sterile inflammations. the freeze-dried form of levofloxacin kits was prepared and found to meet all the radiochemical and biological tests

Internet-enabled collaborative agent-based supply chains

Science.gov (United States)

Shen, Weiming; Kremer, Rob; Norrie, Douglas H.

2000-12-01

This paper presents some results of our recent research work related to the development of a new Collaborative Agent System Architecture (CASA) and an Infrastructure for Collaborative Agent Systems (ICAS). Initially being proposed as a general architecture for Internet based collaborative agent systems (particularly complex industrial collaborative agent systems), the proposed architecture is very suitable for managing the Internet enabled complex supply chain for a large manufacturing enterprise. The general collaborative agent system architecture with the basic communication and cooperation services, domain independent components, prototypes and mechanisms are described. Benefits of implementing Internet enabled supply chains with the proposed infrastructure are discussed. A case study on Internet enabled supply chain management is presented.

Lanthanum-doped mesostructured strontium titanates synthesized via sol–gel combustion route using citric acid as complexing agent

Energy Technology Data Exchange (ETDEWEB)

Sukpanish, Polthep [Department of Chemical Technology, Faculty of Science, Chulalongkorn University, Patumwan, Bangkok 10330 (Thailand); Center of Excellence on Petrochemical and Materials Technology (PETROMAT), Chulalongkorn University, Patumwan, Bangkok 10330 (Thailand); Lertpanyapornchai, Boontawee [Program in Petrochemistry, Faculty of Science, Chulalongkorn University, Patumwan, Bangkok 10330 (Thailand); Yokoi, Toshiyuki [Division of Catalytic Chemistry, Chemical Resources Laboratory, Tokyo Institute of Technology, 4259 Nagatsuta, Midori-ku, Yokohama 226-8503 (Japan); Ngamcharussrivichai, Chawalit, E-mail: Chawalit.Ng@chula.ac.th [Department of Chemical Technology, Faculty of Science, Chulalongkorn University, Patumwan, Bangkok 10330 (Thailand); Center of Excellence on Petrochemical and Materials Technology (PETROMAT), Chulalongkorn University, Patumwan, Bangkok 10330 (Thailand)

2016-09-15

In the present work, a series of lanthanum-doped mesostructured strontium titanate (LMST) materials with different La/Sr ratios were synthesized via a sol–gel combustion method in the presence of citric acid as a complexing agent and Pluronic P123 as a templating agent. The effects of the amount of doped La and calcination temperature on the physicochemical properties of the LMSTs were examined using various techniques. Powder X-ray diffraction confirmed the substitution of La{sup 3+} into the SrTiO{sub 3} lattice, generating cubic perovskite La{sub x}Sr{sub 1−x}TiO{sub 3}, for the LMST materials calcined at 600 °C. The purity and crystallinity of the desired perovskite phase were enhanced by citric acid addition. The solubility limit of La{sup 3+} substitution at an La/Sr ratio of 0.43 was determined by structural and morphological studies. Increasing the La doping amount decreased the crystallinity and compositional homogeneity, because an La-rich amorphous phase segregated on the surface, but improved the mesoporosity. N{sub 2} physisorption measurements indicated that the LMSTs had a bimodal pore size distribution, of which the larger one was characterized by the crystallite size of mixed oxides, and the specific surface area of 24.9–37.3 m{sup 2} g{sup −1}. The formation of mesopores in the LMST materials synthesized via sol–gel combustion was explained based on a combination of soft- and hard-templating chemistries. - Highlights: • La-doped mesoporous SrTiO{sub 3} (LMST) was prepared first time via sol-gel combustion. • Pluronic P123 triblock copolymer was used as a cheap templating agent. • Citric acid as a complexing agent enhanced the purity and crystallinity of SrTiO{sub 3}. • The textural properties of LMST were improved by increasing the La doping amount. • Mesopore formation was explained by a combined soft- and hard-templating route.

Agentes globais e esfera local: o pólo automobilístico de Gravataí Global agents and the local level: the Gravataí automotive complex

Directory of Open Access Journals (Sweden)

Sandro Ruduit Garcia

2010-04-01

Full Text Available O artigo tenta discutir aspectos das relações global-local, focalizando o processo de formação e desenvolvimento do pólo automobilístico de Gravataí e suas implicações sociais no âmbito das relações de trabalho e emprego em empresas locais. Ao reconhecer a recente formação do sistema global, supõe-se que a presença de agentes globais em contextos locais tenderia a criar novas dinâmicas sociais que dependeriam de articulações específicas entre conjunturas econômico-institucionais, níveis e tipos de recursos econômicos e sociais disponíveis, e estratégias mobilizadas pelos agentes sociais. Os agentes globais imporiam novas referências competitivas e tecnológicas aos agentes locais, que se achariam, com frequência, despreparados para acompanhar tais exigências. Por outro lado, poderiam ser criadas, com diferentes configurações, chances de acesso a capitais, mercados, tecnologias e conhecimentos, estimulando mudanças nas relações de trabalho e emprego na esfera local. A assimetria nas relações de poder econômico não impediria a reação dos agentes locais, nas possibilidades de seus recursos e nos horizontes de seus valores, às novas regras e condições do sistema internacional. A relação global-local teria, portanto, implicações distintas entre os agentes sociais.This article discusses aspects of the global-local relations, focusing on the process of formation and development of the Gravataí automotive complex and its social implications as related to the labor relations and employment in local companies. In accordance with the recent formation of the global system, it is assumed that the presence of global agents in local contexts creates new social dynamics that depend on specific arrangements between economic and institutional circumstances, levels and types of available social and economic resources, and strategies mobilized by social agents. The global agents would impose new competitive and

Developing Agent-Oriented Video Surveillance System through Agent-Oriented Methodology (AOM

Directory of Open Access Journals (Sweden)

Cheah Wai Shiang

2016-12-01

Full Text Available Agent-oriented methodology (AOM is a comprehensive and unified agent methodology for agent-oriented software development. Although AOM is claimed to be able to cope with a complex system development, it is still not yet determined up to what extent this may be true. Therefore, it is vital to conduct an investigation to validate this methodology. This paper presents the adoption of AOM in developing an agent-oriented video surveillance system (VSS. An intruder handling scenario is designed and implemented through AOM. AOM provides an alternative method to engineer a distributed security system in a systematic manner. It presents the security system at a holistic view; provides a better conceptualization of agent-oriented security system and supports rapid prototyping as well as simulation of video surveillance system.

Revisiting caffeate's capabilities as a complexation agent to silver cation in mining processes by means of the dual descriptor--a conceptual DFT approach.

Science.gov (United States)

Martínez-Araya, Jorge Ignacio

2012-09-01

Caffeic acid (C(9)H(8)O(4)) and its conjugate base C(9)H(7)O(4) (-) (anionic form-known as caffeate) were analyzed computationally through the use of quantum chemistry to assess their intrinsic global and local reactivity using the tools of conceptual density functional theory. The anionic form was found to be better at coordinating the silver cation than caffeic acid thus suggesting the use of caffeate as a complexation agent. The complexation capability of caffeate was compared with that of some of the most common ligand agents used to coordinate silver cations. Local reactivity descriptors allowed identification of the preferred sites on caffeate for silver cation coordination thus generating a plausible silver complex. All silver complexes were analyzed thermodynamically considering interaction energies in both gas and aqueous phases; the complexation free energy in aqueous phase was also determined. These results suggest that more attention be paid to the caffeate anion and its derivatives because this work has shed new light on the behavior of this anion in the recovery of silver cations that could be exploited in silver mining processes in a environmentally friendly way.

Anticancer Agents: Does a Phosphonium Behave Like a Gold(I) Phosphine Complex? Let a "Smart" Probe Answer!

Science.gov (United States)

Ali, Moussa; Dondaine, Lucile; Adolle, Anais; Sampaio, Carla; Chotard, Florian; Richard, Philippe; Denat, Franck; Bettaieb, Ali; Le Gendre, Pierre; Laurens, Véronique; Goze, Christine; Paul, Catherine; Bodio, Ewen

2015-06-11

Gold phosphine complexes, such as auranofin, have been recognized for decades as antirheumatic agents. Clinical trials are now underway to validate their use in anticancer or anti-HIV treatments. However, their mechanisms of action remain unclear. A challenging question is whether the gold phosphine complex is a prodrug that is administered in an inactive precursor form or rather that the gold atom remains attached to the phosphine ligand during treatment. In this study, we present two novel gold complexes, which we compared to auranofin and to their phosphonium analogue. The chosen ligand is a phosphine-based smart probe, whose strong fluorescence depends on the presence of the gold atom. The in vitro biological action of the gold complexes and the phosphonium derivative were investigated, and a preliminary in vivo study in healthy zebrafish larvae allowed us to evaluate gold complex biodistribution and toxicity. The different analyses carried out showed that these gold complexes were stable and behaved differently from phosphonium and auranofin, both in vitro and in vivo. Two-photon microscopy experiments demonstrated that the cellular targets of these gold complexes are not the same as those of the phosphonium analogue. Moreover, despite similar IC50 values in some cancer cell lines, gold complexes displayed a low toxicity in vivo, in contrast to the phosphonium salt. They are therefore suitable for future in vivo investigations.

Gadolinium heteropoly complex K 17[Gd(P 2W 17O 61) 2] as a potential MRI contrast agent

Science.gov (United States)

Sun, Guoying; Feng, Jianghua; Wu, Huifeng; Pei, Fengkui; Fang, Ke; Lei, Hao

2004-10-01

Gadolinium heteropoly complex K17[Gd(P2W17O61)2] has been evaluated by in vitro and in vivo experiments as a potential contrast agent for magnetic resonance imaging (MRI). The thermal analysis and conductivity study indicate that this complex has good thermal stability and wide pH stability range. The T1 relaxivity is 7.59 mM-1 s-1 in aqueous solution and 7.97 mM-1 s-1 in 0.725 mmol l-1 bovine serum albumin (BSA) solution at 25 °C and 9.39 T, respectively. MR imaging of three male Sprague-Dawley rats showed remarkable enhancement in rat liver after intravenous injection, which persisted longer than with Gd-DTPA. The signal intensity increased by 57.1±16.9% during the whole imaging period at 0.082 mmol kg-1dose. Our preliminary in vitro and in vivo studies indicate that K17[Gd(P2W17O61)2] is a potential liver-specific MRI contrast agent.

Advantages of paramagnetic chemical exchange saturation transfer (CEST) complexes having slow to intermediate water exchange properties as responsive MRI agents.

Science.gov (United States)

Soesbe, Todd C; Wu, Yunkou; Dean Sherry, A

2013-07-01

Paramagnetic chemical exchange saturation transfer (PARACEST) complexes are exogenous contrast agents that have great potential to further extend the functional and molecular imaging capabilities of magnetic resonance. As a result of the presence of a central paramagnetic lanthanide ion (Ln(3+) ≠ La(3+) , Gd(3+) , Lu(3+) ) within the chelate, the resonance frequencies of exchangeable protons bound to the PARACEST agent are shifted far away from the bulk water frequency. This large chemical shift, combined with an extreme sensitivity to the chemical exchange rate, make PARACEST agents ideally suited for the reporting of significant biological metrics, such as temperature, pH and the presence of metabolites. In addition, the ability to turn PARACEST agents 'off' and 'on' using a frequency-selective saturation pulse gives them a distinct advantage over Gd(3+) -based contrast agents. A current challenge for PARACEST research is the translation of the promising in vitro results into in vivo systems. This short review article first describes the basic theory behind PARACEST contrast agents, their benefits over other contrast agents and their applications to MRI. It then describes some of the recent PARACEST research results: specifically, pH measurements using water molecule exchange rate modulation, T2 exchange contrast caused by water molecule exchange, the use of ultrashort TEs (TE < 10 µs) to overcome T2 exchange line broadening and the potential application of T2 exchange as a new contrast mechanism for MRI. Copyright © 2012 John Wiley & Sons, Ltd.

Technetium complexation by macrocyclic compounds

International Nuclear Information System (INIS)

Li Fan Yu.

1983-01-01

Research in nuclear medicine are directed towards the labelling of biological molecules, however, sup(99m)Tc does not show sufficient affinity for these molecules. The aim of this study was to evaluate the ability of macrocyclic compounds to bind strongly technetium in order to be used as complexation intermediate. The reducing agents used were a stannous complex and sodium dithionite. Cryptates and polyesters are not good complexing agents. They form two complexes: a 2:1 sandwich complex or 3:2 and a 1:1 complex. Cyclams are good complexing agents for technetium their complexations strength was determined by competition with pyrophosphate, gluconate and DTPA. Using the method of ligand exchange, the oxidation state of technetium in the Tc-cyclam complex was IV or V. They are 1:1 cationic complexes, the complex charge is +1. The biodistribution in rats of labelling solutions containing (cyclam 14 ane N 4 ) C 12 H 25 shows a good urinary excretion without intoxication risks [fr

Agent-Based Models in Social Physics

Science.gov (United States)

Quang, Le Anh; Jung, Nam; Cho, Eun Sung; Choi, Jae Han; Lee, Jae Woo

2018-06-01

We review the agent-based models (ABM) on social physics including econophysics. The ABM consists of agent, system space, and external environment. The agent is autonomous and decides his/her behavior by interacting with the neighbors or the external environment with the rules of behavior. Agents are irrational because they have only limited information when they make decisions. They adapt using learning from past memories. Agents have various attributes and are heterogeneous. ABM is a non-equilibrium complex system that exhibits various emergence phenomena. The social complexity ABM describes human behavioral characteristics. In ABMs of econophysics, we introduce the Sugarscape model and the artificial market models. We review minority games and majority games in ABMs of game theory. Social flow ABM introduces crowding, evacuation, traffic congestion, and pedestrian dynamics. We also review ABM for opinion dynamics and voter model. We discuss features and advantages and disadvantages of Netlogo, Repast, Swarm, and Mason, which are representative platforms for implementing ABM.

Preparation of new technetium-99m NNS/X complexes and selection for brain imaging agent

Institute of Scientific and Technical Information of China (English)

HE; Qiange; CHEN; Xiangji; MIAO; Yubin; LIU; Boli

2004-01-01

Based on excellent experiment results of 99mTcO-MPBDA-Cl, two new ligands MPTDA and MPDAA are synthesized. Then series of 99mTcO3+ complexes are prepared through adding different halide anions, followed by tests of physical chemistry qualities and biodistribution experiments. And results of these experiments show that complexes formed with MPTDA and MPDAA have better lipophilicity than those formed with MPBDA, still maintain the good brain retention ability of this type of compounds, but radioactivity uptake in blood is higher than that of 99mTcO-MPBDA and ratios of brain/blood are reduced. Obvious affections are fetched out on brain uptake and retention if fluoride, bromide or iodide anions are added. Results of experiments can be explained in reason with theoretic computation. It is confirmed that 99mTcO-MPBDA-Cl has potential to develop a new type of brain imaging agent considering integrated factors such as brain uptake, retention and toxicity.

Complex between lignin and a Ti-based coupling agent

DEFF Research Database (Denmark)

Rasmussen, Jonas Stensgaard; Barsberg, Søren Talbro; Felby, Claus

2014-01-01

-fourier transform infrared spectroscopy in combination with first principle predictions based on the density functional theory (DFT). In the infrared spectra, a new band at 1586 cm-1 was identified and the DFT predictions confirmed that the new band is because of the covalent bonds in the form of ether linkages...... coating formulations would have a better performance if the adhesion to wood could be improved. In the present work, the chemical interaction between a titanium-based coupling agent, isopropyl triisostearoyl titanate (titanium agent, TA) and lignin has been studied by means of attenuated total reflectance...

Effective ODE Zones in a Multi- Agent System

DEFF Research Database (Denmark)

Hjorth, Poul G.

Simulations which contain a large number of agents with rules for agent-agent interactions may grow to a level of complexity where it is cumbersome to extract useful information, difficult to split or agregate parts, and taxing on computational resources. We present here an example where a coarse...... graining of the system, and replacement of individual interactions with ODEs describing dynamical interactions between ‘effective zones’, leads to a fast and useful simplified model of the original complex system....

Complexing agents and pH influence on chemical durability of type I moulded glass containers.

Science.gov (United States)

Biavati, Alberto; Poncini, Michele; Ferrarini, Arianna; Favaro, Nicola; Scarpa, Martina; Vallotto, Marta

2017-06-16

Among the factors that affect the glass surface chemical durability, pH and complexing agents presence in aqueous solution have the main role (1). Glass surface attack can be also related to the delamination issue with glass particles appearance in the pharmaceutical preparation. A few methods to check for glass containers delamination propensity and some control guidelines have been proposed (2,3). The present study emphasizes the possible synergy between a few complexing agents with pH on the borosilicate glass chemical durability. Hydrolytic attack was performed in small volume 23 ml type I glass containers autoclaved according to EP or USP for 1 hour at 121°C, in order to enhance the chemical attack due to time, temperature and the unfavourable surface/volume ratio. 0,048 M or 0.024 M (moles/liter) solutions of the acids citric, glutaric, acetic, EDTA (ethylenediaminetetraacetic acid) and sodium phosphate with water for comparison, were used for the trials. The pH was adjusted ± 0,05 units at fixed values 5,5-6,6-7-7,4-8-9 by LiOH diluted solution. Since silicon is the main glass network former, silicon release into the attack solutions was chosen as the main index of the glass surface attack and analysed by ICPAES. The work was completed by the analysis of the silicon release in the worst attack conditions, of moulded glass, soda lime type II and tubing borosilicate glass vials to compare different glass compositions and forming technologies. Surface analysis by SEM was finally performed to check for the surface status after the worst chemical attack condition by citric acid. Copyright © 2017, Parenteral Drug Association.

Contrast agents for MRI

International Nuclear Information System (INIS)

Bonnemain, B.

1994-01-01

Contrast agents MRI (Magnetic Resonance Imaging) have been developed to improve the diagnostic information obtained by this technic. They mainly interact on T1 and T2 parameters and increase consequently normal to abnormal tissues contrast. The paramagnetic agents which mainly act on longitudinal relaxation rate (T1) are gadolinium complexes for which stability is the main parameter to avoid any release of free gadolinium. The superparamagnetic agents that decrease signal intensity by an effect on transversal relaxation rate (T2) are developed for liver, digestive and lymph node imaging. Many area of research are now opened for optimal use of present and future contrast agents in MRI. (author). 28 refs., 4 tabs

Modelling a Society of Simple Agents: From Conceptual Specification to Experimentation

NARCIS (Netherlands)

Brazier, F.M.; van Eck, P.A.T.; Treur, J.

Much research concerning the design of multi-agent systems (at a conceptual level) addresses complex agents that exhibit complex interaction patterns. Due to this complexity, it is difficult to perform rigorous experimentation. On the other hand, systematic experimental work regarding behaviour of

Interactions of ionic and nonionic contrast agents with thrombolytic agents

International Nuclear Information System (INIS)

Fareed, J.; Moncada, R.; Scanlon, P.; Hoppensteadt, D.; Huan, X.; Walenga, J.M.

1987-01-01

Both the ionic and nonionic intravascular contrast media have been used before and after the administration of thrombolytic agents to evaluate clot lysis during angioplasty and the treatment of myocardial infarction. In experimental animal models, the authors found that the clot lytic efficacy of streptokinase, streptokinase-plasminogen complex, and tissue plasminogen activator (t-PA) is markedly augmented if these agents are administered within 1 hour after the angiographic producers. Furthermore, contrast agents injected after the administration of t-Pa exhibit a synergistic action. In stimulated models administration of one ionic contrast medium (Angiovist, Berlex, Wayne, NJ) and two nonionic contrast agents (Isovue-370, Squibb Diagnostics, New Brunswick, NJ; Omnipaque-350, Winthrop, NY) 15 minutes before the administration of t-PA resulted in marked enhancement of the lytic activity. Although the mechanism of this interaction is unknown at this time, it should be taken into consideration in the treatment of patients with myocardial infarction, in whom contrast agents are continually used to evaluate the therapeutic lysis. Furthermore, this interaction may be partly related to the therapeutic efficacy and/or hemorrhagic actions observed

Mononuclear Pd(II) complex as a new therapeutic agent: Synthesis, characterization, biological activity, spectral and DNA binding approaches

Science.gov (United States)

Saeidifar, Maryam; Mirzaei, Hamidreza; Ahmadi Nasab, Navid; Mansouri-Torshizi, Hassan

2017-11-01

The binding ability between a new water-soluble palladium(II) complex [Pd(bpy)(bez-dtc)]Cl (where bpy is 2,2‧-bipyridine and bez-dtc is benzyl dithiocarbamate), as an antitumor agent, and calf thymus DNA was evaluated using various physicochemical methods, such as UV-Vis absorption, Competitive fluorescence studies, viscosity measurement, zeta potential and circular dichroism (CD) spectroscopy. The Pd(II) complex was synthesized and characterized using elemental analysis, molar conductivity measurements, FT-IR, 1H NMR, 13C NMR and electronic spectra studies. The anticancer activity against HeLa cell lines demonstrated lower cytotoxicity than cisplatin. The binding constants and the thermodynamic parameters were determined at different temperatures (300 K, 310 K and 320 K) and shown that the complex can bind to DNA via electrostatic forces. Furthermore, this result was confirmed by the viscosity and zeta potential measurements. The CD spectral results demonstrated that the binding of Pd(II) complex to DNA induced conformational changes in DNA. We hope that these results will provide a basis for further studies and practical clinical use of anticancer drugs.

Complex Automated Negotiations Theories, Models, and Software Competitions

CERN Document Server

Zhang, Minjie; Robu, Valentin; Matsuo, Tokuro

2013-01-01

Complex Automated Negotiations are a widely studied, emerging area in the field of Autonomous Agents and Multi-Agent Systems. In general, automated negotiations can be complex, since there are a lot of factors that characterize such negotiations. For this book, we solicited papers on all aspects of such complex automated negotiations, which are studied in the field of Autonomous Agents and Multi-Agent Systems. This book includes two parts, which are Part I: Agent-based Complex Automated Negotiations and Part II: Automated Negotiation Agents Competition. Each chapter in Part I is an extended version of ACAN 2011 papers after peer reviews by three PC members. Part II includes ANAC 2011 (The Second Automated Negotiating Agents Competition), in which automated agents who have different negotiation strategies and implemented by different developers are automatically negotiate in the several negotiation domains. ANAC is an international competition in which automated negotiation strategies, submitted by a number of...

Agent-Based Modeling: A Powerful Tool for Tourism Researchers

NARCIS (Netherlands)

Nicholls, Sarah; Amelung, B.; Student, Jillian

2017-01-01

Agent-based modeling (ABM) is a way of representing complex systems of autonomous agents or actors, and of simulating the multiple potential outcomes of these agents’ behaviors and interactions in the form of a range of alternatives or futures. Despite the complexity of the tourism system, and the

Peptaibol, Secondary‐Metabolite, and Hydrophobin Pattern of Commercial Biocontrol Agents Formulated with Species of the Trichoderma harzianum Complex

DEFF Research Database (Denmark)

Degenkolb, Thomas; Nielsen, Kristian Fog; Dieckmann, Ralf

2015-01-01

The production of bioactive polypeptides (peptaibiotics) in vivo is a sophisticated adaptation strategy of both mycoparasitic and saprotrophic Trichoderma species for colonizing and defending their natural habitats. This feature is of major practical importance, as the detection of peptaibiotics...... in plant‐protective Trichoderma species, which are successfully used against economically relevant bacterial and fungal plant pathogens, certainly contributes to a better understanding of these complex antagonistic interactions. We analyzed five commercial biocontrol agents (BCAs), namely Canna®, Trichosan......®, Vitalin®, Promot® WP, and TrichoMax®, formulated with recently described species of the Trichoderma harzianum complex, viz. T. afroharzianum, T. simmonsii, and T. guizhouense. By using the well‐established, HPLC/MS‐based peptaibiomics approach, it could unequivocally be demonstrated that all...

Metareasoning and Social Evaluations in Cognitive Agents

Science.gov (United States)

Pinyol, Isaac; Sabater-Mir, Jordi

Reputation mechanisms have been recognized one of the key technologies when designing multi-agent systems. They are specially relevant in complex open environments, becoming a non-centralized mechanism to control interactions among agents. Cognitive agents tackling such complex societies must use reputation information not only for selecting partners to interact with, but also in metareasoning processes to change reasoning rules. This is the focus of this paper. We argue about the necessity to allow, as a cognitive systems designers, certain degree of freedom in the reasoning rules of the agents. We also describes cognitive approaches of agency that support this idea. Furthermore, taking as a base the computational reputation model Repage, and its integration in a BDI architecture, we use the previous ideas to specify metarules and processes to modify at run-time the reasoning paths of the agent. In concrete we propose a metarule to update the link between Repage and the belief base, and a metarule and a process to update an axiom incorporated in the belief logic of the agent. Regarding this last issue we also provide empirical results that show the evolution of agents that use it.

Study of the leaching of heavy metals from waste water sludge and incinerator's ash, using coupled thermostated columns and DTPA as complex agent; Estudio de la extraccion de metales pesados de lodos y cenizas de aguas residuales usando columnas termostatizadas acopladas y DTPA como agente complejante

Energy Technology Data Exchange (ETDEWEB)

Vite T, J.; Vite T, M.; Guerrero D, J.; Carreno de Leon, M.C. [Departamento de Estudios del Ambiente, Instituto Nacional de Investigaciones Nucleares, A.P. 18-1027, 11801 Mexico D.F. (Mexico)

2000-07-01

We studied the metallic composition from waste water sludge and incinerators ashes of an incinerator located in Toluca, Mexico, the qualitative studies were made using the Activation Analysis technique, and fluorescence X-ray techniques. The quantitative analysis of heavy metals in the wastes were made using Inductively coupled plasma atomic emission spectrometry (Icp-Aes). For leaching the samples, we used four coupled thermostated columns, each one had a p H of 2,5, 7 and 10. The flux of the air was of 1600 cc/min. The temperature was maintain constant in 60 Centigrade using a thermostated system. For this study we used 100 g of wastes mixed with mineral acid or sodium hydroxide to reach p H 2,5,7 and 10. We added a reducing and tensoactive agents and finally DTPA as complex agent. With this method, we obtain a better leaching efficiency using a complex agent. However the high DTPA cost, make this process expansive that is why we recommend to work with another classes of complex agents, that be cheaper to leach metals of different chemistry matrix. (Author)

Flame-Sprayed Y2O3 Films with Metal-EDTA Complex Using Various Cooling Agents

Science.gov (United States)

Komatsu, Keiji; Toyama, Ayumu; Sekiya, Tetsuo; Shirai, Tomoyuki; Nakamura, Atsushi; Toda, Ikumi; Ohshio, Shigeo; Muramatsu, Hiroyuki; Saitoh, Hidetoshi

2017-01-01

In this study, yttrium oxide (Y2O3) films were synthesized from a metal-ethylenediaminetetraacetic (metal-EDTA) complex by employing a H2-O2 combustion flame. A rotation apparatus and various cooling agents (compressed air, liquid nitrogen, and atomized purified water) were used during the synthesis to control the thermal history during film deposition. An EDTA·Y·H complex was prepared and used as the staring material for the synthesis of Y2O3 films with a flame-spraying apparatus. Although thermally extreme environments were employed during the synthesis, all of the obtained Y2O3 films showed only a few cracks and minor peeling in their microstructures. For instance, the Y2O3 film synthesized using the rotation apparatus with water atomization units exhibited a porosity of 22.8%. The maximum film's temperature after deposition was 453 °C owing to the high heat of evaporation of water. Cooling effects of substrate by various cooling units for solidification was dominated to heat of vaporization, not to unit's temperatures.

A New Bis(aquated) High Relaxivity Mn(II) Complex as an Alternative to Gd(III)-Based MRI Contrast Agent.

Science.gov (United States)

Phukan, Bedika; Mukherjee, Chandan; Goswami, Upashi; Sarmah, Amrit; Mukherjee, Subhajit; Sahoo, Suban K; Moi, Sankar Ch

2018-03-05

Disclosed here are a piperazine, a pyridine, and two carboxylate groups containing pentadentate ligand H 2 pmpa and its corresponding water-soluble Mn(II) complex (1). DFT-based structural optimization implied that the complex had pentagonal bipyramidal geometry where the axial positions were occupied by two water molecules, and the equatorial plane was constituted by the ligand ON 3 O donor set. Thus, a bis(aquated) disc-like Mn(II) complex has been synthesized. The complex showed higher stability compared with Mn(II)-EDTA complex [log K MnL = 14.29(3)] and showed a very high r 1 relaxivity value of 5.88 mM -1 s -1 at 1.41 T, 25 °C, and pH = 7.4. The relaxivity value remained almost unaffected by the pH of the medium in the range of 6-10. Although the presence of 200 equiv of fluoride and bicarbonate anions did not affect the relaxivity value appreciably, an increase in the value was noticed in the presence of phosphate anion due to slow tumbling of the complex. Cell viability measurements, as well as phantom MR images using clinical MRI imager, consolidated the possible candidature of complex 1 as a positive contrast agent.

Specific sequestering agents for iron and the actinides

Energy Technology Data Exchange (ETDEWEB)

Raymond, K.N.

1983-06-01

The transuranium actinide ions represent one unique environmental hazard associated with the waste of the nuclear power industry. A major component associated with that waste and a potential hazard is plutonium. The synthesis of metal-ion-specific complexing agents for ions such as Pu(IV) potentially represents a powerful new approach to many of the problems posed by waste treatment. This document is a progress report of a rational approach to the synthesis of such chelating agents based on the similarities of Pu(IV) and Fe(III), the structures of naturally-occurring complexing agents which are highly specific for Fe(III), and the incorporation of the same kinds of ligating groups present in the iron complexes to make octadentate complexes highly specific for plutonium. Both thermodynamic and animal test results indicate that a relatively high degree of success has already been achieved in this aim.

Design and simulation of material-integrated distributed sensor processing with a code-based agent platform and mobile multi-agent systems.

Science.gov (United States)

Bosse, Stefan

2015-02-16

Multi-agent systems (MAS) can be used for decentralized and self-organizing data processing in a distributed system, like a resource-constrained sensor network, enabling distributed information extraction, for example, based on pattern recognition and self-organization, by decomposing complex tasks in simpler cooperative agents. Reliable MAS-based data processing approaches can aid the material-integration of structural-monitoring applications, with agent processing platforms scaled to the microchip level. The agent behavior, based on a dynamic activity-transition graph (ATG) model, is implemented with program code storing the control and the data state of an agent, which is novel. The program code can be modified by the agent itself using code morphing techniques and is capable of migrating in the network between nodes. The program code is a self-contained unit (a container) and embeds the agent data, the initialization instructions and the ATG behavior implementation. The microchip agent processing platform used for the execution of the agent code is a standalone multi-core stack machine with a zero-operand instruction format, leading to a small-sized agent program code, low system complexity and high system performance. The agent processing is token-queue-based, similar to Petri-nets. The agent platform can be implemented in software, too, offering compatibility at the operational and code level, supporting agent processing in strong heterogeneous networks. In this work, the agent platform embedded in a large-scale distributed sensor network is simulated at the architectural level by using agent-based simulation techniques.

Design and Simulation of Material-Integrated Distributed Sensor Processing with a Code-Based Agent Platform and Mobile Multi-Agent Systems

Directory of Open Access Journals (Sweden)

Stefan Bosse

2015-02-01

Full Text Available Multi-agent systems (MAS can be used for decentralized and self-organizing data processing in a distributed system, like a resource-constrained sensor network, enabling distributed information extraction, for example, based on pattern recognition and self-organization, by decomposing complex tasks in simpler cooperative agents. Reliable MAS-based data processing approaches can aid the material-integration of structural-monitoring applications, with agent processing platforms scaled to the microchip level. The agent behavior, based on a dynamic activity-transition graph (ATG model, is implemented with program code storing the control and the data state of an agent, which is novel. The program code can be modified by the agent itself using code morphing techniques and is capable of migrating in the network between nodes. The program code is a self-contained unit (a container and embeds the agent data, the initialization instructions and the ATG behavior implementation. The microchip agent processing platform used for the execution of the agent code is a standalone multi-core stack machine with a zero-operand instruction format, leading to a small-sized agent program code, low system complexity and high system performance. The agent processing is token-queue-based, similar to Petri-nets. The agent platform can be implemented in software, too, offering compatibility at the operational and code level, supporting agent processing in strong heterogeneous networks. In this work, the agent platform embedded in a large-scale distributed sensor network is simulated at the architectural level by using agent-based simulation techniques.

Towards the Rational Design of MRI Contrast Agents: Electron Spin Relaxation Is Largely Unaffected by the Coordination Geometry of Gadolinium(III)–DOTA-Type Complexes

Science.gov (United States)

Bean, Jonathan F.; Clarkson, Robert B.; Helm, Lothar; Moriggi, Loïck; Sherry, A. Dean

2009-01-01

Electron-spin relaxation is one of the determining factors in the efficacy of MRI contrast agents. Of all the parameters involved in determining relaxivity it remains the least well understood, particularly as it relates to the structure of the complex. One of the reasons for the poor understanding of electron-spin relaxation is that it is closely related to the ligand-field parameters of the Gd3+ ion that forms the basis of MRI contrast agents and these complexes generally exhibit a structural isomerism that inherently complicates the study of electron spin relaxation. We have recently shown that two DOTA-type ligands could be synthesised that, when coordinated to Gd3+, would adopt well defined coordination geometries and are not subject to the problems of intramolecular motion of other complexes. The EPR properties of these two chelates were studied and the results examined with theory to probe their electron-spin relaxation properties. PMID:18283704

Handheld Delivery System for Modified Boron-Type Fire Extinguishment Agent

Science.gov (United States)

1993-11-01

was to develop and test a handheld portable delivery system for use with the modified boron-type fire extinguishing agent for metal fires . B...BACKGROUND A need exists for an extinguishing agent and accompanying delivery system that are effective against complex geometry metal fires . A modified...agent and its delivery system have proven effective against complex geometry metal fires containing up to 200 pounds of magnesium metal. Further

Quantum Speedup for Active Learning Agents

Directory of Open Access Journals (Sweden)

Giuseppe Davide Paparo

2014-07-01

Full Text Available Can quantum mechanics help us build intelligent learning agents? A defining signature of intelligent behavior is the capacity to learn from experience. However, a major bottleneck for agents to learn in real-life situations is the size and complexity of the corresponding task environment. Even in a moderately realistic environment, it may simply take too long to rationally respond to a given situation. If the environment is impatient, allowing only a certain time for a response, an agent may then be unable to cope with the situation and to learn at all. Here, we show that quantum physics can help and provide a quadratic speedup for active learning as a genuine problem of artificial intelligence. This result will be particularly relevant for applications involving complex task environments.

Using the Agent-Based Modeling in Economic Field

Directory of Open Access Journals (Sweden)

Nora Mihail

2006-12-01

Full Text Available The last ten years of the XX century has been the witnesses of the apparition of a new scientific field, which is usually defined as the study of “Complex adaptive systems”. This field, generic named Complexity Sciences, shares its subject, the general proprieties of complex systems across traditional disciplinary boundaries, with cybernetics and general systems theory. But the development of Complexity Sciences approaches is determined by the extensive use of Agent-Based-Models (ABM as a research tool and an emphasis on systems, such as markets, populations or ecologies, which are less integrated or “organized” than the ones, such as companies and economies, intensively studied by the traditional disciplines. For ABM, a complex system is a system of individual agents who have the freedom to act in ways that are not always totally predictable, and whose actions are interconnected such that one agent’s actions changes the context (environment for other agents. These are many examples of such complex systems: the stock market, the human body immune system, a business organization, an institution, a work-team, a family etc.

Development of radiolanthanide labeled porphyrin complexes as possible therapeutic agents in beast carcinoma xenografts

Energy Technology Data Exchange (ETDEWEB)

Vahidfar, Nasim; Aghanejad, Ayuob; Beiki, Davood; Khalaj, Ali [Tehran University of Medical Sciences, Tehran (Iran, Islamic Republic of). Faculty of Pharmacy; Jalilian, Amir R.; Fazaeli, Yousef; Bahrami-Samani, Ali; Alirezapour, Behrooz; Erfani, Mostafa [Nuclear Science and Technology Research Institute, Tehran (Iran, Islamic Republic of). Radiopharmacy Research Group

2014-10-01

Radiolabeled porphyrins are potential tumor avid radiopharmaceuticals because of their behaviour in the human body, ability to complex various radionuclides, water solubility, low toxicity etc., in this work radio ytterbium/samarium porphyrin complexes have been developed. {sup 175}Yb and {sup 153}Sm labeled 5,10,15,20-tetrakis(3,4-dimethoxyphenyl) porphyrins ([{sup 175}Yb]-TDMPP/[{sup 153}Sm]-TDMPP) were prepared using 5,10,15,20-tetrakis(3,4-dimethoxyphenyl) porphyrin (H{sub 2}TDMPP) and [{sup 175}Yb]YbCl{sub 3} or [{sup 153}Sm]SmCl{sub 3} in 12-24 h at 60 C. Stability of the complexes were checked in final formulation and human serum for 24 h, followed by partition coefficient determination and biodistribution studies in wild type and breast carcinoma-bearing mice. The radiocomplexes were obtained with acceptable radiochemical purity (> 95% (paper chromatography) and > 96% (HPLC) for [{sup 175}Yb]-TDMPP and > 97% (paper chromatography) and > 98% (HPLC) for [{sup 153}Sm]-TDMPP) with specific activities of 12-15 GBq/mmol and 278 GBq/mmol at the end of bombardment for [{sup 175}Yb]-TDMPP and [{sup 153}Sm]-TDMPP respectively. The partition coefficients were determined for [{sup 175}Yb]-TDMPP and [{sup 153}Sm]-TDMPP (log P = 0.63 and log P = 0.96 respectively). The [{sup 175}Yb]-TDMPP complex is mostly washed out from the circulation through kidneys. Liver and spleen also demonstrated significant activity uptake in 72 h post injection. Also [{sup 153}Sm]-TDMPP, is mostly washed out from the circulation through kidneys, however lungs are the major accumulation sites. The [{sup 153}Sm]-TDMPP complex demonstrated significant targeted uptake in breast carcinoma xenografts with tumor: blood ratios of 10.67, 10.47 and 19.01 in 24, 48 and 72 h respectively. Also interesting tumor: kidney/liver ratios were obtained. {sup 153}Sm-TDMPP properties suggest an efficient tumor targeting agent with high tumor-avidity. Further investigation on the therapeutic properties must be

Synthesis quality control and biodistribution of technetium-99m triamcinolone (99mTc-TA) complex: An inflammation tracer agent

International Nuclear Information System (INIS)

Rizvii, Faheem Askari; Naqvi, Syed Ali Raza; Mehdi, Muhammad; Roohi, Samina; Zahoor, Ameer Fawad; Khan, Zulfiqar Ali; Sohaib, Muhammad; Rasheed, Rashid

2017-01-01

In present study synthesis of 99m Tc-triamcinolone acetonide ( 99m Tc-TA) complex and its stability using set of quality control parameters such as ligand concentration, reducing agent concentration, pH, temperature and reaction time was assessed. 99m Tc-TA complex was characterized in terms of percent (%) yield, stability in saline and serum using chromatographic procedures. Radiochemically the 99m Tc-TA complex was found quite stable in saline and serum. After 30 min of reaction the complex showed maximum radiochemical yield of 96.32% which decreased to 96.25 % after 4 h incubation period. In serum, the % yield of radiochemical was remained same up to 2 h which decreased to 93.5% at 24 h time point. Normal biodistribution pattern in Sprague-Dawley rats revealed liver, stomach and kidneys as areas of high 99m Tc-TA complex uptake (8.44 ±1.32, 8.75 ± 1.03 and 12.67 ± 1.21%, respectively) at 1 h post injection time point. Scintigraphy of 99m Tc-TA in rabbits showed similar eco as observed in biodistribution study. Based on the promising results obtained in context of in vitro and in vivo stability and biodistribution, 99m Tc-TA complex could be further studied to identify the inflammation based diseases

Using the Agent-Based Modeling in Economic Field

Directory of Open Access Journals (Sweden)

Nora Mihail

2006-10-01

For ABM, a complex system is a system of individual agents who have the freedom to act in ways that are not always totally predictable, and whose actions are interconnected such that one agent’s actions changes the context (environment for other agents. These are many examples of such complex systems: the stock market, the human body immune system, a business organization, an institution, a work-team, a family etc.

Theoretical investigation of inclusion complex formation of Gold (III – Dimethyldithiocarbamate anticancer agents with cucurbit[n = 5,6]urils

Directory of Open Access Journals (Sweden)

Zabiollah Mahdavifar

2014-09-01

Full Text Available Gold (III-N,N-dimethyldithiocarbamate [DMDT(AuX2] complexes have recently gained increasing attention as potential anticancer agents because of their strong tumor cell growth–inhibitory effects, generally achieved by exploiting non-cisplatin-like mechanisms of action. The goal of our research work is to encapsulate the gold(III dimethyldithiocarbamate complexes as anticancer with cucurbit[n]urils (CB[n = 5, 6] by accurate calculations, to predict the inclusion complex formation of gold(III species with cucurbiturils (CB[n = 5, 6]. The calculations were carried out just for the 1:1 stoichiometric complexes. Upon encapsulation, binding energy, thermodynamic parameters, structural parameters and electronic structures of complexes are investigated. The results of the thermodynamic calculations and the binding energy show that the inclusion process is exothermic and the CB[6]/[DMDT(AuBr2] complex is more stable than other complexes. The final geometry of CB[n]/drugs indicates that the drugs were expelled from the cavity of CB[n]. NBO calculations reveal that the hydrogen bonding between CB[n] and drugs and electrostatic interactions are the major factors contributing to the overall stabilities of the complexes.

An Approach for Autonomy: A Collaborative Communication Framework for Multi-Agent Systems

Science.gov (United States)

Dufrene, Warren Russell, Jr.

2005-01-01

Research done during the last three years has studied the emersion properties of Complex Adaptive Systems (CAS). The deployment of Artificial Intelligence (AI) techniques applied to remote Unmanned Aerial Vehicles has led the author to investigate applications of CAS within the field of Autonomous Multi-Agent Systems. The core objective of current research efforts is focused on the simplicity of Intelligent Agents (IA) and the modeling of these agents within complex systems. This research effort looks at the communication, interaction, and adaptability of multi-agents as applied to complex systems control. The embodiment concept applied to robotics has application possibilities within multi-agent frameworks. A new framework for agent awareness within a virtual 3D world concept is possible where the vehicle is composed of collaborative agents. This approach has many possibilities for applications to complex systems. This paper describes the development of an approach to apply this virtual framework to the NASA Goddard Space Flight Center (GSFC) tetrahedron structure developed under the Autonomous Nano Technology Swarm (ANTS) program and the Super Miniaturized Addressable Reconfigurable Technology (SMART) architecture program. These projects represent an innovative set of novel concepts deploying adaptable, self-organizing structures composed of many tetrahedrons. This technology is pushing current applied Agents Concepts to new levels of requirements and adaptability.

Agent-based models in economics a toolkit

CERN Document Server

Fagiolo, Giorgio; Gallegati, Mauro; Richiardi, Matteo; Russo, Alberto

2018-01-01

In contrast to mainstream economics, complexity theory conceives the economy as a complex system of heterogeneous interacting agents characterised by limited information and bounded rationality. Agent Based Models (ABMs) are the analytical and computational tools developed by the proponents of this emerging methodology. Aimed at students and scholars of contemporary economics, this book includes a comprehensive toolkit for agent-based computational economics, now quickly becoming the new way to study evolving economic systems. Leading scholars in the field explain how ABMs can be applied fruitfully to many real-world economic examples and represent a great advancement over mainstream approaches. The essays discuss the methodological bases of agent-based approaches and demonstrate step-by-step how to build, simulate and analyse ABMs and how to validate their outputs empirically using the data. They also present a wide set of applications of these models to key economic topics, including the business cycle, lab...

3-hydroxy-2(1H)-pyridinone chelating agents

Science.gov (United States)

Raymond, K.; Xu, J.

1999-04-06

Disclosed is a series of improved chelating agents and the chelates formed from these agents, which are highly effective upon both injection and oral administration. Several of the most effective are of low toxicity. These chelating agents incorporate within their structure 3-hydroxy-2-pyridinone (3,2-HOPO) moieties with a substituted carbamoyl group ortho to the hydroxy group of the hydroxypyridinone ring. The electron-withdrawing carbamoyl group increases the acidity, as well as the chemical stability towards oxidation and reduction, of the hydroxypyridinones. In the metal complexes of the chelating agents, the amide protons form very strong hydrogen bonds with the adjacent HOPO oxygen donor, making these complexes very stable at physiological conditions. The terminal N-substituents provide a certain degree of lipophilicity to the 3,2-HOPO, increasing oral activity. 2 figs.

A novel multi-agent decentralized win or learn fast policy hill-climbing with eligibility trace algorithm for smart generation control of interconnected complex power grids

International Nuclear Information System (INIS)

Xi, Lei; Yu, Tao; Yang, Bo; Zhang, Xiaoshun

2015-01-01

Highlights: • Proposing a decentralized smart generation control scheme for the automatic generation control coordination. • A novel multi-agent learning algorithm is developed to resolve stochastic control problems in power systems. • A variable learning rate are introduced base on the framework of stochastic games. • A simulation platform is developed to test the performance of different algorithms. - Abstract: This paper proposes a multi-agent smart generation control scheme for the automatic generation control coordination in interconnected complex power systems. A novel multi-agent decentralized win or learn fast policy hill-climbing with eligibility trace algorithm is developed, which can effectively identify the optimal average policies via a variable learning rate under various operation conditions. Based on control performance standards, the proposed approach is implemented in a flexible multi-agent stochastic dynamic game-based smart generation control simulation platform. Based on the mixed strategy and average policy, it is highly adaptive in stochastic non-Markov environments and large time-delay systems, which can fulfill automatic generation control coordination in interconnected complex power systems in the presence of increasing penetration of decentralized renewable energy. Two case studies on both a two-area load–frequency control power system and the China Southern Power Grid model have been done. Simulation results verify that multi-agent smart generation control scheme based on the proposed approach can obtain optimal average policies thus improve the closed-loop system performances, and can achieve a fast convergence rate with significant robustness compared with other methods

Polymeric hydrogels containing complexant agents for retention of pollutants containing thorium

International Nuclear Information System (INIS)

Oliveira, Maria Jose A.; Carreiro, Julio C.; Parra, Duclerc F.; Lugao, Ademar B.

2005-01-01

The hydrogels of poly(N-vinyl-2-pyrrolidone) (PVP), constituted of around 90% of water , show properties of retaining great amount of water and consequently can also retain substances that were made soluble, with either particular or specific reactive properties. In the light of this, these matrixes can be used as support for both capture and retention of radioactive substances of contaminated surfaces. Modified hydrogels containing complexant agents had been obtained in solution, in order to capture contaminated substances. The study of the ionizing radiation effect in polymer is of great interest not only to the development of materials which operate in conditions of radiation but also to the usage of the technique with purpose of both polymeric structure modification and acquisition of new materials. Membranes of hydrogels have been obtained with poly(N-vinyl-2-pyrrolidone)-PVP, polyethyleneglycol (PEG), Agar and several concentrations of ethylenediaminetetraacetic acid (EDTA), and sodium citrate. Theses samples were irradiated in 60 Co source, 15 kGy/h dose and submitted to thermal characterization in a Mettler-Toledo SDTA/851 equipment. The hydrogels membranes polymerized by radiation were put in contact with thorium nitrate solution, dehydrated and calcined, after that their ashes were analyzed. In the case of solution containing thorium were analyzed by spectrophotometric. (author)

Modeling agents with a theory of mind

NARCIS (Netherlands)

Harbers, M.; Bosch, K. van den; Meyer, J.J.C.

2009-01-01

Training systems with intelligent virtual agents provide an effective means to train people for complex, dynamic tasks like crisis management or firefighting. Virtual agents provide more adequate behavior and explanations if they not only take their own goals and beliefs into account, but also the

The institutional stance in agent-based simulations

NARCIS (Netherlands)

Sileno, G.; Boer, A.; van Engers, T.; Filipe, J.; Fred, A.L.N.

2013-01-01

This paper presents a multi-agent framework intended to animate scenarios of compliance and non-compliance in a normative system. With the purpose of describing social human behaviour, we choose to reduce social complexity by creating models of the involved agents starting from stories, and

1H NMR analysis of complexation of hydrotropic agents nicotinamide and caffeine with aromatic biologically active molecules in aqueous solution

Science.gov (United States)

Lantushenko, Anastasia O.; Mukhina, Yulia V.; Veselkov, Kyrill A.; Davies, David B.; Veselkov, Alexei N.

2004-07-01

NMR spectroscopy has been used to elucidate the molecular mechanism of solubilization action of hydrotropic agents nicotinamide (NA) and caffeine (CAF). Hetero-association of NA with riboflavine-mononucleotide (FMN) and CAF with low soluble in aqueous solution synthetic analogue of antibiotic actinomycin D, actinocyl-bis-(3-dimethylaminopropyl) amine (Actill), has been investigated by 500 MHz 1H NMR spectroscopy. Concentration and temperature dependences of proton chemical shifts have been analysed in terms of a statistical-thermodynamic model of indefinite self- and heteroassociation of aromatic molecules. The obtained results enable to conclude that NA-FMN and CAF-Actill intermolecular complexes are mainly stabilized by the stacking interactions of the aromatic chromophores. Hetero-association of the investigated molecules plays an important role in solubilization of aromatic drugs by hydrotropic agents nicotinamide and caffeine.

Analyzing Katana referral hospital as a complex adaptive system: agents, interactions and adaptation to a changing environment.

Science.gov (United States)

Karemere, Hermès; Ribesse, Nathalie; Marchal, Bruno; Macq, Jean

2015-01-01

This study deals with the adaptation of Katana referral hospital in Eastern Democratic Republic of Congo in a changing environment that is affected for more than a decade by intermittent armed conflicts. His objective is to generate theoretical proposals for addressing differently the analysis of hospitals governance in the aims to assess their performance and how to improve that performance. The methodology applied approach uses a case study using mixed methods ( qualitative and quantitative) for data collection. It uses (1) hospital data to measure the output of hospitals, (2) literature review to identify among others, events and interventions recorded in the history of hospital during the study period and (3) information from individual interviews to validate the interpretation of the results of the previous two sources of data and understand the responsiveness of management team referral hospital during times of change. The study brings four theoretical propositions: (1) Interaction between key agents is a positive force driving adaptation if the actors share a same vision, (2) The strength of the interaction between agents is largely based on the nature of institutional arrangements, which in turn are shaped by the actors themselves, (3) The owner and the management team play a decisive role in the implementation of effective institutional arrangements and establishment of positive interactions between agents, (4) The analysis of recipient population's perception of health services provided allow to better tailor and adapt the health services offer to the population's needs and expectations. Research shows that it isn't enough just to provide support (financial and technical), to manage a hospital for operate and adapt to a changing environment but must still animate, considering that it is a complex adaptive system and that this animation is nothing other than the induction of a positive interaction between agents.

Separation of calcium isotopes with cryptand complexes

International Nuclear Information System (INIS)

Heumann, K.G.; Schiefer, H.P.

1981-01-01

The calcium isotope separation in the liquid-liquid extraction system H 2 O/CHCl 3 is investigated using and cryptands for complex formation as well as without complexing agent. An extraction procedure is used which allows the transfer of larger amounts of calcium in the H 2 O phase. Without complexing agent in the extraction system, enrichment of the lighter calcium isotopes is already evident in the CHCl 3 phase which is just the same as when using cryptand. In the case of cryptand as a complexing agent, the isotope separation is higher. The separation factor is calculated to be a = 1 + epsilon = 1.011 for 40 Ca/ 48 Ca without complexing agent or with cryptand and a = 1.015 in the system with cryptand. For 40 Ca/ 44 Ca the epsilon-value is smaller by nearly a factor of two. These separation factors are the highest which are determined in chemical systems for calcium isotopes. (orig.)

Anti-cancer effects of newly developed chemotherapeutic agent, glycoconjugated palladium (II) complex, against cisplatin-resistant gastric cancer cells

International Nuclear Information System (INIS)

Tanaka, Mamoru; Kamiya, Takeshi; Joh, Takashi; Kataoka, Hiromi; Yano, Shigenobu; Ohi, Hiromi; Kawamoto, Keisuke; Shibahara, Takashi; Mizoshita, Tsutomu; Mori, Yoshinori; Tanida, Satoshi

2013-01-01

Cisplatin (CDDP) is the most frequently used chemotherapeutic agent for various types of advanced cancer, including gastric cancer. However, almost all cancer cells acquire resistance against CDDP, and this phenomenon adversely affects prognosis. Thus, new chemotherapeutic agents that can overcome the CDDP-resistant cancer cells will improve the survival of advanced cancer patients. We synthesized new glycoconjugated platinum (II) and palladium (II) complexes, [PtCl 2 (L)] and [PdCl 2 (L)]. CDDP-resistant gastric cancer cell lines were established by continuous exposure to CDDP, and gene expression in the CDDP-resistant gastric cancer cells was analyzed. The cytotoxicity and apoptosis induced by [PtCl 2 (L)] and [PdCl 2 (L)] in CDDP-sensitive and CDDP-resistant gastric cancer cells were evaluated. DNA double-strand breaks by drugs were assessed by evaluating phosphorylated histone H2AX. Xenograft tumor mouse models were established and antitumor effects were also examined in vivo. CDDP-resistant gastric cancer cells exhibit ABCB1 and CDKN2A gene up-regulation, as compared with CDDP-sensitive gastric cancer cells. In the analyses of CDDP-resistant gastric cancer cells, [PdCl 2 (L)] overcame cross-resistance to CDDP in vitro and in vivo. [PdCl 2 (L)] induced DNA double-strand breaks. These results indicate that [PdCl 2 (L)] is a potent chemotherapeutic agent for CDDP-resistant gastric cancer and may have clinical applications

A methodology for eliciting, representing, and analysing stakeholder knowledge for decision making on complex socio-ecological systems: from cognitive maps to agent-based models.

Science.gov (United States)

Elsawah, Sondoss; Guillaume, Joseph H A; Filatova, Tatiana; Rook, Josefine; Jakeman, Anthony J

2015-03-15

This paper aims to contribute to developing better ways for incorporating essential human elements in decision making processes for modelling of complex socio-ecological systems. It presents a step-wise methodology for integrating perceptions of stakeholders (qualitative) into formal simulation models (quantitative) with the ultimate goal of improving understanding and communication about decision making in complex socio-ecological systems. The methodology integrates cognitive mapping and agent based modelling. It cascades through a sequence of qualitative/soft and numerical methods comprising: (1) Interviews to elicit mental models; (2) Cognitive maps to represent and analyse individual and group mental models; (3) Time-sequence diagrams to chronologically structure the decision making process; (4) All-encompassing conceptual model of decision making, and (5) computational (in this case agent-based) Model. We apply the proposed methodology (labelled ICTAM) in a case study of viticulture irrigation in South Australia. Finally, we use strengths-weakness-opportunities-threats (SWOT) analysis to reflect on the methodology. Results show that the methodology leverages the use of cognitive mapping to capture the richness of decision making and mental models, and provides a combination of divergent and convergent analysis methods leading to the construction of an Agent Based Model. Copyright © 2014 Elsevier Ltd. All rights reserved.

Oxidative phosphorylation-dependent regulation of cancer cell apoptosis in response to anticancer agents.

Science.gov (United States)

Yadav, N; Kumar, S; Marlowe, T; Chaudhary, A K; Kumar, R; Wang, J; O'Malley, J; Boland, P M; Jayanthi, S; Kumar, T K S; Yadava, N; Chandra, D

2015-11-05

Cancer cells tend to develop resistance to various types of anticancer agents, whether they adopt similar or distinct mechanisms to evade cell death in response to a broad spectrum of cancer therapeutics is not fully defined. Current study concludes that DNA-damaging agents (etoposide and doxorubicin), ER stressor (thapsigargin), and histone deacetylase inhibitor (apicidin) target oxidative phosphorylation (OXPHOS) for apoptosis induction, whereas other anticancer agents including staurosporine, taxol, and sorafenib induce apoptosis in an OXPHOS-independent manner. DNA-damaging agents promoted mitochondrial biogenesis accompanied by increased accumulation of cellular and mitochondrial ROS, mitochondrial protein-folding machinery, and mitochondrial unfolded protein response. Induction of mitochondrial biogenesis occurred in a caspase activation-independent mechanism but was reduced by autophagy inhibition and p53-deficiency. Abrogation of complex-I blocked DNA-damage-induced caspase activation and apoptosis, whereas inhibition of complex-II or a combined deficiency of OXPHOS complexes I, III, IV, and V due to impaired mitochondrial protein synthesis did not modulate caspase activity. Mechanistic analysis revealed that inhibition of caspase activation in response to anticancer agents associates with decreased release of mitochondrial cytochrome c in complex-I-deficient cells compared with wild type (WT) cells. Gross OXPHOS deficiencies promoted increased release of apoptosis-inducing factor from mitochondria compared with WT or complex-I-deficient cells, suggesting that cells harboring defective OXPHOS trigger caspase-dependent as well as caspase-independent apoptosis in response to anticancer agents. Interestingly, DNA-damaging agent doxorubicin showed strong binding to mitochondria, which was disrupted by complex-I-deficiency but not by complex-II-deficiency. Thapsigargin-induced caspase activation was reduced upon abrogation of complex-I or gross OXPHOS deficiency

(Pyridine)(tetrahydroborato)zinc complex, (Zn(BH4)2(py)), as a new stable, efficient and chemoselective reducing agent for reduction of carbonyl compounds

International Nuclear Information System (INIS)

Zeynizadeh, Behzad; Faraji, Fariba

2003-01-01

(Pyridine)(tetrahydroborato)zinc complex, (Zn(BH 4 ) 2 (py)), as a stable white solid, was prepared quantitatively by complexation of an equimolar amount of zinc tetrahydroborate and pyridine at room temperature. This reagent can easily reduce variety of carbonyl compounds such as aldehydes, ketones, acyloins, α-diketones and α,β-unsaturated carbonyl compounds to their corresponding alcohols in good to excellent yields. Reduction reactions were performed in ether or THF at room temperature or under reflux conditions. In addition, the chemoselective reduction of aldehydes over ketones was accomplished successfully with this reducing agent

Hypercompetitive Environments: An Agent-based model approach

Science.gov (United States)

Dias, Manuel; Araújo, Tanya

Information technology (IT) environments are characterized by complex changes and rapid evolution. Globalization and the spread of technological innovation have increased the need for new strategic information resources, both from individual firms and management environments. Improvements in multidisciplinary methods and, particularly, the availability of powerful computational tools, are giving researchers an increasing opportunity to investigate management environments in their true complex nature. The adoption of a complex systems approach allows for modeling business strategies from a bottom-up perspective — understood as resulting from repeated and local interaction of economic agents — without disregarding the consequences of the business strategies themselves to individual behavior of enterprises, emergence of interaction patterns between firms and management environments. Agent-based models are at the leading approach of this attempt.

Photocytotoxic lanthanide complexes

Indian Academy of Sciences (India)

Among many applications of lanthanides, gadolinium complexes are used as magnetic resonance imaging (MRI) contrast agents in clinical radiology and luminescent lanthanides for bioanalysis, imaging and sensing. The chemistry of photoactive lanthanide complexes showing biological applications is of recent origin.

Agent-based modeling of sustainable behaviors

CERN Document Server

Sánchez-Maroño, Noelia; Fontenla-Romero, Oscar; Polhill, J; Craig, Tony; Bajo, Javier; Corchado, Juan

2017-01-01

Using the O.D.D. (Overview, Design concepts, Detail) protocol, this title explores the role of agent-based modeling in predicting the feasibility of various approaches to sustainability. The chapters incorporated in this volume consist of real case studies to illustrate the utility of agent-based modeling and complexity theory in discovering a path to more efficient and sustainable lifestyles. The topics covered within include: households' attitudes toward recycling, designing decision trees for representing sustainable behaviors, negotiation-based parking allocation, auction-based traffic signal control, and others. This selection of papers will be of interest to social scientists who wish to learn more about agent-based modeling as well as experts in the field of agent-based modeling.

Multi-agent models of spatial cognition, learning and complex choice behavior in urban environments

NARCIS (Netherlands)

Arentze, Theo; Timmermans, Harry; Portugali, J.

2006-01-01

This chapter provides an overview of ongoing research projects in the DDSS research program at TUE related to multi-agents. Projects include (a) the use of multi-agent models and concepts of artificial intelligence to develop models of activity-travel behavior; (b) the use of a multi-agent model to

Effect of complexing agent TEA: The structural, morphological, topographical and optical properties of FexSx nano thin films deposited by SILAR technique

International Nuclear Information System (INIS)

Manikandan, K.; Mani, P.; Surendra Dilip, C.; Valli, S.; Fermi Hilbert Inbaraj, P.; Joseph Prince, J.

2014-01-01

Iron sulfide thin films (Fe x S x ) (x = 0.05 M, 0.10 M, 0.15 M, 0.20 M and 0.25 M) were deposited by SILAR method from equimolar and equivolume aqueous solutions of ferrous nitrate and sodium sulfide with the addition of complexing agent TEA. The structural, morphological and optical characteristics of the films were derived from X-ray diffraction (XRD), scanning electron microscopy (SEM), atomic force microscopy (AFM) and UV–vis spectral techniques. The mixed characteristics (crystalline and amorphous) of the deposited films and the increasing crystalline qualities with the concentrations were understood from the XRD analysis. The grain sizes and roughness of the films were decreases with the increasing concentration and also at the higher concentration films are shown by the same images presence of hexagonal like crystallite structure. The influence of complexing agent TEA on the surface roughness and morphological properties are confirmed by the atomic force microscope (AFM) results. The effect of increasing substrate concentration on the absorption and transmission measurements and its impact on the optical band-gap energy were enumerated from the UV–vis analysis.

Dembo polymerase chain reaction technique for detection of bovine abortion, diarrhea, and respiratory disease complex infectious agents in potential vectors and reservoirs.

Science.gov (United States)

Rahpaya, Sayed Samim; Tsuchiaka, Shinobu; Kishimoto, Mai; Oba, Mami; Katayama, Yukie; Nunomura, Yuka; Kokawa, Saki; Kimura, Takashi; Kobayashi, Atsushi; Kirino, Yumi; Okabayashi, Tamaki; Nonaka, Nariaki; Mekata, Hirohisa; Aoki, Hiroshi; Shiokawa, Mai; Umetsu, Moeko; Morita, Tatsushi; Hasebe, Ayako; Otsu, Keiko; Asai, Tetsuo; Yamaguchi, Tomohiro; Makino, Shinji; Murata, Yoshiteru; Abi, Ahmad Jan; Omatsu, Tsutomu; Mizutani, Tetsuya

2018-05-31

Bovine abortion, diarrhea, and respiratory disease complexes, caused by infectious agents, result in high and significant economic losses for the cattle industry. These pathogens are likely transmitted by various vectors and reservoirs including insects, birds, and rodents. However, experimental data supporting this possibility are scarce. We collected 117 samples and screened them for 44 bovine abortive, diarrheal, and respiratory disease complex pathogens by using Dembo polymerase chain reaction (PCR), which is based on TaqMan real-time PCR. Fifty-seven samples were positive for at least one pathogen, including bovine viral diarrhea virus, bovine enterovirus, Salmonella enterica ser. Dublin, Salmonella enterica ser. Typhimurium, and Neospora caninum ; some samples were positive for multiple pathogens. Bovine viral diarrhea virus and bovine enterovirus were the most frequently detected pathogens, especially in flies, suggesting an important role of flies in the transmission of these viruses. Additionally, we detected the N. caninum genome from a cockroach sample for the first time. Our data suggest that insects (particularly flies), birds, and rodents are potential vectors and reservoirs of abortion, diarrhea, and respiratory infectious agents, and that they may transmit more than one pathogen at the same time.

Smart swarms of bacteria-inspired agents with performance adaptable interactions.

Directory of Open Access Journals (Sweden)

Adi Shklarsh

2011-09-01

Full Text Available Collective navigation and swarming have been studied in animal groups, such as fish schools, bird flocks, bacteria, and slime molds. Computer modeling has shown that collective behavior of simple agents can result from simple interactions between the agents, which include short range repulsion, intermediate range alignment, and long range attraction. Here we study collective navigation of bacteria-inspired smart agents in complex terrains, with adaptive interactions that depend on performance. More specifically, each agent adjusts its interactions with the other agents according to its local environment--by decreasing the peers' influence while navigating in a beneficial direction, and increasing it otherwise. We show that inclusion of such performance dependent adaptable interactions significantly improves the collective swarming performance, leading to highly efficient navigation, especially in complex terrains. Notably, to afford such adaptable interactions, each modeled agent requires only simple computational capabilities with short-term memory, which can easily be implemented in simple swarming robots.

Smart swarms of bacteria-inspired agents with performance adaptable interactions.

Science.gov (United States)

Shklarsh, Adi; Ariel, Gil; Schneidman, Elad; Ben-Jacob, Eshel

2011-09-01

Collective navigation and swarming have been studied in animal groups, such as fish schools, bird flocks, bacteria, and slime molds. Computer modeling has shown that collective behavior of simple agents can result from simple interactions between the agents, which include short range repulsion, intermediate range alignment, and long range attraction. Here we study collective navigation of bacteria-inspired smart agents in complex terrains, with adaptive interactions that depend on performance. More specifically, each agent adjusts its interactions with the other agents according to its local environment--by decreasing the peers' influence while navigating in a beneficial direction, and increasing it otherwise. We show that inclusion of such performance dependent adaptable interactions significantly improves the collective swarming performance, leading to highly efficient navigation, especially in complex terrains. Notably, to afford such adaptable interactions, each modeled agent requires only simple computational capabilities with short-term memory, which can easily be implemented in simple swarming robots.

Assessing Consequential Scenarios in a Complex Operational Environment Using Agent Based Simulation

Science.gov (United States)

2017-03-16

capabilities and maturities of 4 subelements: cognition, judgment, emotion , and critical thinking. Each model represents these subelements differently...CADSIM) 102 5.2 Evaluating Agent-Based Technologies: Maturity Level and the Human Domain 103 5.2.1 Evaluation of Maturity Level 103 5.2.2 Human...describes the maturity of agent-based models, ranging from realistic caricatures to quantitatively characterized phenomena at the microlevel. This

Inhibitory effects of antimicrobial agents against Fusarium species.

Science.gov (United States)

Kawakami, Hideaki; Inuzuka, Hiroko; Hori, Nobuhide; Takahashi, Nobumichi; Ishida, Kyoko; Mochizuki, Kiyofumi; Ohkusu, Kiyofumi; Muraosa, Yasunori; Watanabe, Akira; Kamei, Katsuhiko

2015-08-01

We investigated the inhibitory effects of antibacterial, biocidal, and antifungal agents against Fusarium spp. Seven Fusarium spp: four F. falciforme (Fusarium solani species complex), one Fusarium spp, one Fusarium spp. (Fusarium incarnatum-equiseti species complex), and one F. napiforme (Gibberella fujikuroi species complex), isolated from eyes with fungal keratitis were used in this study. Their susceptibility to antibacterial agents: flomoxef, imipenem, gatifloxacin, levofloxacin, moxifloxacin, gentamicin, tobramycin, and Tobracin® (contained 3,000 μg/ml of tobramycin and 25 μg/ml of benzalkonium chloride (BAK), a biocidal agent: BAK, and antifungal agents: amphotericin B, pimaricin (natamycin), fluconazole, itraconazole, miconazole, voriconazole, and micafungin, was determined by broth microdilution tests. The half-maximal inhibitory concentration (IC50), 100% inhibitory concentration (IC100), and minimum inhibitory concentration (MIC) against the Fusarium isolates were determined. BAK had the highest activity against the Fusarium spp. except for the antifungal agents. Three fluoroquinolones and two aminoglycosides had inhibitory effects against the Fusarium spp. at relatively high concentrations. Tobracin® had a higher inhibitory effect against Fusarium spp. than tobramycin alone. Amphotericin B had the highest inhibitory effect against the Fusarium spp, although it had different degrees of activity against each isolate. Our findings showed that fluoroquinolones, aminoglycosides, and BAK had some degree of inhibitory effect against the seven Fusarium isolates, although these agents had considerably lower effect than amphotericin B. However, the inhibitory effects of amphotericin B against the Fusarium spp. varied for the different isolates. Further studies for more effective medications against Fusarium, such as different combinations of antibacterial, biocidal, and antifungal agents are needed. © The Author 2015. Published by Oxford University Press on

The Principal-Agent model and the European Union

NARCIS (Netherlands)

Delreux, Tom; Adriaensen, J.

2017-01-01

This book assesses the use and limitations of the principal-agent model in a context of increasingly complex political systems such as the European Union. Whilst a number of conceptual, theoretical and methodological challenges need to be addressed, the authors show that the principal-agent model

Flexible Decision Control in an Autonomous Trading Agent

NARCIS (Netherlands)

J. Collins (John); W. Ketter (Wolfgang); M. Gini (Maria)

2007-01-01

textabstractAn autonomous trading agent is a complex piece of software that must operate in a competitive economic environment and support a research agenda. We describe the structure of decision processes in the MinneTAC trading agent, focusing on the use of evaluators – configurable, composable

Functional copolymer/organo-MMT nanoarchitectures. VI. Synthesis and characterization of novel nanocomposites by interlamellar controlled/living radical copolymerization via preintercalated RAFT-agent/organoclay complexes.

Science.gov (United States)

Rzayev, Zakir M O; Söylemez, A Ernur

2011-04-01

We have developed a new approach for the synthesis of polymer nanocomposites using a bifunctional reversible addition-fragmentation chain transfer (RAFT) agent, two types of organo-montmorillonites, such as a non-reactive dimethyldodecyl ammonium (DMDA)-MMT and a reactive octadecylamine (ODA)-MMT organoclays, and a radical initiator. The method includes the following stages: (1) synthesis of RAFT intercalated O-MMTs by a physical or chemical interaction of the RAFT agent having two pendant carboxylic groups [S,S-bis(alpha,alpha'-dimethyl-alpha"-acetic acid)trithiocarbonate] with surface alkyl amines of O-MMT containing tertiary ammonium cation or primary amine groups through strong H-bonding and complexing/amidization reactions, respectively, and (2) utilization of these well-dispersed and intercalated RAFT ... O-MMT complexes and their amide derivatives as new modified RAFT agents in radical-initiated interlamellar controlled/living copolymerization of itaconic acid (IA)-n-butylmethacrylate (BMA) monomer pair. The structure and compositions of the synthesized RAFT ... O-MMT complexes and functional copolymer/O-MMT hybrids were confirmed by FTIR, XRD, thermal (DSC-TGA), SEM and TEM morphology analyses. It was demonstrated that the degree of interaction/exfoliation, morphology and thermal behavior of nanocomposites significantly depended on the type of organoclay and in situ interaction, as well as on the content of flexible butyl-ester linkages as a internal plasticizer. The results of the comparative analysis of the nanocomposites structure-composition-property relations show that the functional copolymer-organoclay hybrids prepared with reactive RAFT ... ODA-MMT complex and containing a combination of partially intercalated and predominantly exfoliated nano-structures exhibit relatively higher thermal stability and fine dispersed morphology. These effects were explained by in situ interfacial chemical reactions through amidization of RAFT with surface alkyl amine

Complexing Agents and pH Influence on Chemical Durability of Type I Molded Glass Containers.

Science.gov (United States)

Biavati, Alberto; Poncini, Michele; Ferrarini, Arianna; Favaro, Nicola; Scarpa, Martina; Vallotto, Marta

2017-01-01

Among the factors that affect the glass surface chemical durability, pH and complexing agents present in aqueous solution have the main role. Glass surface attack can be also related to the delamination issue causing glass particles' appearance in the pharmaceutical preparation. A few methods to check for glass containers delamination propensity and some control guidelines have been proposed. The present study emphasizes the possible synergy between a few complexing agents with pH on borosilicate glass chemical durability.Hydrolytic attack was performed in small-volume 23 mL type I glass containers autoclaved according to the European Pharmacopoeia or United States Pharmacopeia for 1 h at 121 °C, in order to enhance the chemical attack due to time, temperature, and the unfavorable surface/volume ratio. Solutions of 0.048 M or 0.024 M (M/L) of the acids citric, glutaric, acetic, EDTA (ethylenediaminetetraacetic acid), together with sodium phosphate with water for comparison, were used for the trials. The pH was adjusted ±0.05 units at fixed values 5.5, 6.6, 7, 7.4, 8, and 9 by LiOH diluted solution.Because silicon is the main glass network former, silicon release into the attack solutions was chosen as the main index of the glass surface attack and analysed by inductively coupled plasma atomic emission spectrophotometry. The work was completed by the analysis of the silicon release in the worst attack conditions of molded glass, soda lime type II glass, and tubing borosilicate glass vials to compare different glass compositions and forming technologies. Surface analysis by scanning electron microscopy was finally performed to check for the surface status after the worst chemical attack condition by citric acid. LAY ABSTRACT: Glass, like every packaging material, can have some usage limits, mainly in basic pH solutions. The issue of glass surface degradation particles that appear in vials (delamination) has forced a number of drug product recalls in recent years

Fast and low-temperature sintering of silver complex using oximes as a potential reducing agent for solution-processible, highly conductive electrodes

International Nuclear Information System (INIS)

Yoo, Ji Hoon; Park, Su Bin; Kim, Ji Man; Han, Dae Sang; Chae, Jangwoo; Kwak, Jeonghun

2014-01-01

Highly conductive, solution-processed silver thin-films were obtained at a low sintering temperature of 100 °C in a short sintering time of 10 min by introducing oximes as a potential reductant for silver complex. The thermal properties and reducibility of three kinds of oximes, acetone oxime, 2-butanone oxime, and one dimethylglyoxime, were investigated as a reducing agent, and we found that the thermal decomposition product of oximes (ketones) accelerated the conversion of silver complex into highly conductive silver at low sintering temperature in a short time. Using the acetone oxime, the silver thin-film exhibited the lowest surface resistance (0.91 Ω sq −1 ) compared to those sing other oximes. The silver thin-film also showed a high reflectance of 97.8%, which is comparable to evaporated silver films. We also demonstrated inkjet printed silver patterns with the oxime-added silver complex inks. (paper)

BSL-3 laboratory practices in the United States: comparison of select agent and non-select agent facilities.

Science.gov (United States)

Richards, Stephanie L; Pompei, Victoria C; Anderson, Alice

2014-01-01

New construction of biosafety level 3 (BSL-3) laboratories in the United States has increased in the past decade to facilitate research on potential bioterrorism agents. The Centers for Disease Control and Prevention inspect BSL-3 facilities and review commissioning documentation, but no single agency has oversight over all BSL-3 facilities. This article explores the extent to which standard operating procedures in US BSL-3 facilities vary between laboratories with select agent or non-select agent status. Comparisons are made for the following variables: personnel training, decontamination, personal protective equipment (PPE), medical surveillance, security access, laboratory structure and maintenance, funding, and pest management. Facilities working with select agents had more complex training programs and decontamination procedures than non-select agent facilities. Personnel working in select agent laboratories were likely to use powered air purifying respirators, while non-select agent laboratories primarily used N95 respirators. More rigorous medical surveillance was carried out in select agent workers (although not required by the select agent program) and a higher level of restrictive access to laboratories was found. Most select agent and non-select agent laboratories reported adequate structural integrity in facilities; however, differences were observed in personnel perception of funding for repairs. Pest management was carried out by select agent personnel more frequently than non-select agent personnel. Our findings support the need to promote high quality biosafety training and standard operating procedures in both select agent and non-select agent laboratories to improve occupational health and safety.

A meta-ontological framework for multi-agent systems design

OpenAIRE

Sokolova, Marina; Fernández Caballero, Antonio

2007-01-01

The paper introduces an approach to using a meta-ontology framework for complex multi-agent systems design, and illustrates it in an application related to ecological-medical issues. The described shared ontology is pooled from private sub-ontologies, which represent a problem area ontology, an agent ontology, a task ontology, an ontology of interactions, and the multi-agent system architecture ontology.

Synthesis and characterization of ligands and bifunctional chelating agents by modification of cysteine for complexation studies with 99mTc

International Nuclear Information System (INIS)

Pillai, M.R.A.; Kothari, K.; Banerjee, S.; Samuel, G.; Suresh, M.; Sarma, H.D.

1998-01-01

The synthesis of four novel ligands using the amino-acid cysteine and its ethyl carboxylate derivative is described. The synthetic method involves a two-step procedure, wherein the intermediate Schiff base formed by the condensation of the amino group of the cysteine substrate and salicylaldehyde is reduced to give the target ligands. The intermediates and the final products are characterised by high resolution NMR spectroscopy. Complexation studies of the ligands with 99m Tc are standardised using stannous tartrate as the reducing agent at varying reaction conditions. The complexes are characterised using standard quality control techniques such as TLC, paper electrophoresis and PC. Lipophilicities of the complexes are estimated by solvent extraction into chloroform. Substantial changes in net charge and lipophilicity in the 99m Tc complexes are observed on substituting the carboxylic acid residue in ligand I and II with the ethyl carboxylate groups (ligands III and IV). All the ligands formed complexes in high yield. While the complexes of ligand I and II are observed to be hydrophilic in nature and are not extractable into CHCl 3 , ligands III and IV gave neutral and lipophilic complexes. Though the distribution ratios of the complexes of ligands III and IV in CHCl 3 /saline system are observed to be very high, considerable differences in lipophilicities are also observed as evidenced by the difference in their respective extractabilities in chloroform. On storage, the complex of ligand III exhibit a tendency to get converted to a hydrophilic and non-extractable species. The bio-distribution of the complexes of ligands I and II showed that they have predominantly renal clearances whereas the complexes of ligands III and IV exhibited a significant hepatobiliary uptake and did not show much uptake in brain in spite of its favourable properties such as neutrality, lipophilicity and conversion into a hydrophilic species. (author)

Agent-Based Computing: Promise and Perils

OpenAIRE

Jennings, N. R.

1999-01-01

Agent-based computing represents an exciting new synthesis both for Artificial Intelligence (AI) and, more genrally, Computer Science. It has the potential to significantly improve the theory and practice of modelling, designing and implementing complex systems. Yet, to date, there has been little systematic analysis of what makes an agent such an appealing and powerful conceptual model. Moreover, even less effort has been devoted to exploring the inherent disadvantages that stem from adoptin...

Coupling the capabilities of different complexing agents into deep eutectic solvents to enhance the separation of aromatics from aliphatics

International Nuclear Information System (INIS)

Hizaddin, Hanee F.; Sarwono, Mulyono; Hashim, Mohd Ali; Alnashef, Inas M.; Hadj-Kali, Mohamed K.

2015-01-01

Highlights: • DESs made of three constituents are used for the separation of hydrocarbon mixture. • Ethylene glycol and pyridine are used as complexing agents for the DESs. • Addition of ethylene glycol results in increased selectivity of aromatics. • Increasing the molar ratio of pyridine improve the distribution ratio. • Ternary LLE results are well correlated with NRTL model and COSMO-RS prediction. - Abstract: (Liquid + liquid) extraction of ethylbenzene from n-octane by using tetrabutylammonium bromide-based deep eutectic solvents (DESs) containing pyridine, ethylene glycol, or a mixture of both complexing agents was investigated at 25 °C and atmospheric pressure. The performance of each DES was determined from the distribution ratio and selectivity values calculated using experimental (liquid + liquid) equilibrium data of the ternary systems ethylbenzene + n-octane + DESs. The DES with only ethylene glycol had a high selectivity but a low distribution ratio, whereas the DES with only pyridine had a high distribution ratio but a low selectivity. For the other DESs, adding pyridine increased the distribution ratio, and increasing the molar ratio of ethylene glycol increased the selectivity. Generally, whenever the selectivity increased, the distribution ratio decreased, and vice versa. The nonrandom two-liquid model was used to correlate the experimental data, and the average root mean square deviation (RMSD) between correlated and experimental tie lines was 1.4%. Moreover, the Conductor-like Screening Model for Real Solvents was successfully used to predict the ternary tie lines for the studied systems with an average RMSD of 3.7%

Simulating social complexity a handbook

CERN Document Server

Meyer, Ruth

2013-01-01

Social systems are among the most complex known. This poses particular problems for those who wish to understand them. The complexity often makes analytic approaches infeasible and natural language approaches inadequate for relating intricate cause and effect. However, individual- and agent-based computational approaches hold out the possibility of new and deeper understanding of such systems.  Simulating Social Complexity examines all aspects of using agent- or individual-based simulation. This approach represents systems as individual elements having each their own set of differing states and internal processes. The interactions between elements in the simulation represent interactions in the target systems. What makes these elements "social" is that they are usefully interpretable as interacting elements of an observed society. In this, the focus is on human society, but can be extended to include social animals or artificial agents where such work enhances our understanding of human society.  The phenom...

Evaluating Water Demand Using Agent-Based Modeling

Science.gov (United States)

Lowry, T. S.

2004-12-01

The supply and demand of water resources are functions of complex, inter-related systems including hydrology, climate, demographics, economics, and policy. To assess the safety and sustainability of water resources, planners often rely on complex numerical models that relate some or all of these systems using mathematical abstractions. The accuracy of these models relies on how well the abstractions capture the true nature of the systems interactions. Typically, these abstractions are based on analyses of observations and/or experiments that account only for the statistical mean behavior of each system. This limits the approach in two important ways: 1) It cannot capture cross-system disruptive events, such as major drought, significant policy change, or terrorist attack, and 2) it cannot resolve sub-system level responses. To overcome these limitations, we are developing an agent-based water resources model that includes the systems of hydrology, climate, demographics, economics, and policy, to examine water demand during normal and extraordinary conditions. Agent-based modeling (ABM) develops functional relationships between systems by modeling the interaction between individuals (agents), who behave according to a probabilistic set of rules. ABM is a "bottom-up" modeling approach in that it defines macro-system behavior by modeling the micro-behavior of individual agents. While each agent's behavior is often simple and predictable, the aggregate behavior of all agents in each system can be complex, unpredictable, and different than behaviors observed in mean-behavior models. Furthermore, the ABM approach creates a virtual laboratory where the effects of policy changes and/or extraordinary events can be simulated. Our model, which is based on the demographics and hydrology of the Middle Rio Grande Basin in the state of New Mexico, includes agent groups of residential, agricultural, and industrial users. Each agent within each group determines its water usage

DNA-protein complexes induced by chromate and other carcinogens

International Nuclear Information System (INIS)

Costa, M.

1991-01-01

DNA-protein complexes induced in intact Chinese hamster ovary cells by chromate have been isolated, analyzed, and compared with those induced by cis-platinum, ultraviolet light, and formaldehyde. Actin has been identified as one of the major proteins complexed to DNA by chromate based upon its molecular weight, isoelectric point, positive reaction with an actin polyclonal antibody, and proteolytic mapping. Chromate and cis-platinum both complex proteins of similar molecular weight and isoelectric point, positive reaction with an actin polyclonal antibody, and proteolytic mapping. Chromate and cis-platinum both complex proteins of similar molecular weight and isoelectric points, and these complexes can be disrupted by chelating agents and sulfhydryl reducing agents, suggesting that the metal itself is participating in binding rather than having a catalytic or indirect role (i.e., oxygen radicals). In contrast, formaldehyde complexed histones to the DNA, and these complexes were not disrupted by chelating or reducing agents. An antiserum raised to chromate-induced DNA-protein complexes reacted primarily with 97,000 kDa protein that did not silver stain. Slot blots, as well as Western blots, were used to detect formation of p97 DNA crosslinks. This protein was complexed to the DNA by all four agents studied

Deploying Affect-Inspired Mechanisms to Enhance Agent Decision-Making and Communication

OpenAIRE

Antos, Dimitrios

2012-01-01

Computer agents are required to make appropriate decisions quickly and efficiently. As the environments in which they act become increasingly complex, efficient decision-making becomes significantly more challenging. This thesis examines the positive ways in which human emotions influence people’s ability to make good decisions in complex, uncertain contexts, and develops computational analogues of these beneficial functions, demonstrating their usefulness in agent decision-making and communi...

Stability of subsystem solutions in agent-based models

Science.gov (United States)

Perc, Matjaž

2018-01-01

The fact that relatively simple entities, such as particles or neurons, or even ants or bees or humans, give rise to fascinatingly complex behaviour when interacting in large numbers is the hallmark of complex systems science. Agent-based models are frequently employed for modelling and obtaining a predictive understanding of complex systems. Since the sheer number of equations that describe the behaviour of an entire agent-based model often makes it impossible to solve such models exactly, Monte Carlo simulation methods must be used for the analysis. However, unlike pairwise interactions among particles that typically govern solid-state physics systems, interactions among agents that describe systems in biology, sociology or the humanities often involve group interactions, and they also involve a larger number of possible states even for the most simplified description of reality. This begets the question: when can we be certain that an observed simulation outcome of an agent-based model is actually stable and valid in the large system-size limit? The latter is key for the correct determination of phase transitions between different stable solutions, and for the understanding of the underlying microscopic processes that led to these phase transitions. We show that a satisfactory answer can only be obtained by means of a complete stability analysis of subsystem solutions. A subsystem solution can be formed by any subset of all possible agent states. The winner between two subsystem solutions can be determined by the average moving direction of the invasion front that separates them, yet it is crucial that the competing subsystem solutions are characterised by a proper composition and spatiotemporal structure before the competition starts. We use the spatial public goods game with diverse tolerance as an example, but the approach has relevance for a wide variety of agent-based models.

Adaptive hierarchical multi-agent organizations

NARCIS (Netherlands)

Ghijsen, M.; Jansweijer, W.N.H.; Wielinga, B.J.; Babuška, R.; Groen, F.C.A.

2010-01-01

In this chapter, we discuss the design of adaptive hierarchical organizations for multi-agent systems (MAS). Hierarchical organizations have a number of advantages such as their ability to handle complex problems and their scalability to large organizations. By introducing adaptivity in the

Competing intelligent search agents in global optimization

Energy Technology Data Exchange (ETDEWEB)

Streltsov, S.; Vakili, P. [Boston Univ., MA (United States); Muchnik, I. [Rutgers Univ., Piscataway, NJ (United States)

1996-12-31

In this paper we present a new search methodology that we view as a development of intelligent agent approach to the analysis of complex system. The main idea is to consider search process as a competition mechanism between concurrent adaptive intelligent agents. Agents cooperate in achieving a common search goal and at the same time compete with each other for computational resources. We propose a statistical selection approach to resource allocation between agents that leads to simple and efficient on average index allocation policies. We use global optimization as the most general setting that encompasses many types of search problems, and show how proposed selection policies can be used to improve and combine various global optimization methods.

Nanodiamond-Manganese dual mode MRI contrast agents for enhanced liver tumor detection.

Science.gov (United States)

Hou, Weixin; Toh, Tan Boon; Abdullah, Lissa Nurrul; Yvonne, Tay Wei Zheng; Lee, Kuan J; Guenther, Ilonka; Chow, Edward Kai-Hua

2017-04-01

Contrast agent-enhanced magnetic resonance (MR) imaging is critical for the diagnosis and monitoring of a number of diseases, including cancer. Certain clinical applications, including the detection of liver tumors, rely on both T1 and T2-weighted images even though contrast agent-enhanced MR imaging is not always reliable. Thus, there is a need for improved dual mode contrast agents with enhanced sensitivity. We report the development of a nanodiamond-manganese dual mode contrast agent that enhanced both T1 and T2-weighted MR imaging. Conjugation of manganese to nanodiamonds resulted in improved longitudinal and transverse relaxivity efficacy over unmodified MnCl 2 as well as clinical contrast agents. Following intravenous administration, nanodiamond-manganese complexes outperformed current clinical contrast agents in an orthotopic liver cancer mouse model while also reducing blood serum concentration of toxic free Mn 2+ ions. Thus, nanodiamond-manganese complexes may serve as more effective dual mode MRI contrast agent, particularly in cancer. Copyright © 2016 Elsevier Inc. All rights reserved.

Bifunctional chelating agent for the design and development of site specific radiopharmaceuticals and biomolecule conjugation strategy

Science.gov (United States)

Katti, Kattesh V.; Prabhu, Kandikere R.; Gali, Hariprasad; Pillarsetty, Nagavara Kishore; Volkert, Wynn A.

2003-10-21

There is provided a method of labeling a biomolecule with a transition metal or radiometal in a site specific manner to produce a diagnostic or therapeutic pharmaceutical compound by synthesizing a P.sub.2 N.sub.2 -bifunctional chelating agent intermediate, complexing the intermediate with a radio metal or a transition metal, and covalently linking the resulting metal-complexed bifunctional chelating agent with a biomolecule in a site specific manner. Also provided is a method of synthesizing the --PR.sub.2 containing biomolecules by synthesizing a P.sub.2 N.sub.2 -bifunctional chelating agent intermediate, complexing the intermediate with a radiometal or a transition metal, and covalently linking the resulting radio metal-complexed bifunctional chelating agent with a biomolecule in a site specific manner. There is provided a therapeutic or diagnostic agent comprising a --PR.sub.2 containing biomolecule.

(Pyridine)(tetrahydroborato)zinc complex, (Zn(BH{sub 4}){sub 2}(py)), as a new stable, efficient and chemoselective reducing agent for reduction of carbonyl compounds

Energy Technology Data Exchange (ETDEWEB)

Zeynizadeh, Behzad; Faraji, Fariba [Urima Univ., Urima (Iran, Islamic Republic of)

2003-04-01

(Pyridine)(tetrahydroborato)zinc complex, (Zn(BH{sub 4}){sub 2}(py)), as a stable white solid, was prepared quantitatively by complexation of an equimolar amount of zinc tetrahydroborate and pyridine at room temperature. This reagent can easily reduce variety of carbonyl compounds such as aldehydes, ketones, acyloins, {alpha}-diketones and {alpha},{beta}-unsaturated carbonyl compounds to their corresponding alcohols in good to excellent yields. Reduction reactions were performed in ether or THF at room temperature or under reflux conditions. In addition, the chemoselective reduction of aldehydes over ketones was accomplished successfully with this reducing agent.

A strategy learning model for autonomous agents based on classification

Directory of Open Access Journals (Sweden)

Śnieżyński Bartłomiej

2015-09-01

Full Text Available In this paper we propose a strategy learning model for autonomous agents based on classification. In the literature, the most commonly used learning method in agent-based systems is reinforcement learning. In our opinion, classification can be considered a good alternative. This type of supervised learning can be used to generate a classifier that allows the agent to choose an appropriate action for execution. Experimental results show that this model can be successfully applied for strategy generation even if rewards are delayed. We compare the efficiency of the proposed model and reinforcement learning using the farmer-pest domain and configurations of various complexity. In complex environments, supervised learning can improve the performance of agents much faster that reinforcement learning. If an appropriate knowledge representation is used, the learned knowledge may be analyzed by humans, which allows tracking the learning process

Gold(I) complex of 1,1'-bis(diphenylphosphino) ferrocene-quinoline conjugate: a virostatic agent against HIV-1.

Science.gov (United States)

Gama, Ntombenhle; Kumar, Kamlesh; Ekengard, Erik; Haukka, Matti; Darkwa, James; Nordlander, Ebbe; Meyer, Debra

2016-06-01

HIV infection is known for replicating in proliferating CD(+) T-cells. Treatment of these cells with cytostatic (anti-proliferation) compounds such as hydroxyurea interferes with the cells's ability support HIV replication. Combinations of such cytostatic compounds with proven anti-retroviral drugs (like ddI) are known as virostatic, and have been shown to aid in the control of the infection. The use of two different drugs in virostatic combinations however, carries the risk of adverse effects including drug-drug interactions, which could lead to augmented toxicities and reduced efficacy. Here, a novel digold(I) complex of ferrocene-quinoline (3) was investigated for cytostatic behaviour as well as anti-viral activity which if demonstrated would eliminate concerns of drug-drug interactions. The complex was synthesized and characterized by NMR, FT-IR and mass spectroscopy and the molecular structure was confirmed by X-ray crystallography. Bio-screening involved viability dyes, real time electronic sensing and whole virus assays. The complex showed significant (p = 0.0092) inhibition of virus infectivity (83 %) at 10 ug/mL. This same concentration caused cytostatic behaviour in TZM-bl cells with significant (p < 0.01) S and G2/M phase cell cycle arrest. These data supports 3 as a virostatic agent, possessing both anti-viral and cytostatic characteristics. In the absence of 3, TZM-bl cells were infected by a pseudovirus and this was demonstrated through luminescence in a luciferase assay. Pre-incubation of the virus with 3 decreased luminescence, indicating the anti-viral activity of 3. Complex 3 also showed cytostatic behavior with increased S-phase and G2/M phase cell cycle arrest.

Complexity, cognition and the city

CERN Document Server

Portugali, Juval

2011-01-01

Complexity, Cognition and the City aims at a deeper understanding of urbanism, while invoking, on an equal footing, the contributions both the hard and soft sciences have made, and are still making, when grappling with the many issues and facets of regional planning and dynamics. In this work, the author goes beyond merely seeing the city as a self-organized, emerging pattern of some collective interaction between many stylized urban "agents" – he makes the crucial step of attributing cognition to his agents and thus raises, for the first time, the question on how to deal with a complex system composed of many interacting complex agents in clearly defined settings. Accordingly, the author eventually addresses issues of practical relevance for urban planners and decision makers. The book unfolds its message in a largely nontechnical manner, so as to provide a broad interdisciplinary readership with insights, ideas, and other stimuli to encourage further research – with the twofold aim of further pushing ba...

Development of Semantic Web-Enabled BDI Multi-Agent Systems Using SEA_ML: An Electronic Bartering Case Study

OpenAIRE

Challenger, M.; Tezel, Baris Tekin; Alaca, Ömer Faruk; Tekinerdogan, B.; Kardas, Geylani

2018-01-01

In agent-oriented software engineering (AOSE), the application of model-driven development (MDD) and the use of domain-specific modeling languages (DSMLs) for Multi-Agent System (MAS) development are quite popular since the implementation of MAS is naturally complex, error-prone, and costly due to the autonomous and proactive properties of the agents. The internal agent behavior and the interaction within the agent organizations become even more complex and hard to implement when the requirem...

Regulated open multi-agent systems (ROMAS) a multi-agent approach for designing normative open systems

CERN Document Server

Garcia, Emilia; Botti, Vicente

2015-01-01

Addressing the open problem of engineering normative open systems using the multi-agent paradigm, normative open systems are explained as systems in which heterogeneous and autonomous entities and institutions coexist in a complex social and legal framework that can evolve to address the different and often conflicting objectives of the many stakeholders involved. Presenting  a software engineering approach which covers both the analysis and design of these kinds of systems, and which deals with the open issues in the area, ROMAS (Regulated Open Multi-Agent Systems) defines a specific multi-agent architecture, meta-model, methodology and CASE tool. This CASE tool is based on Model-Driven technology and integrates the graphical design with the formal verification of some properties of these systems by means of model checking techniques. Utilizing tables to enhance reader insights into the most important requirements for designing normative open multi-agent systems, the book also provides a detailed and easy t...

Socially intelligent autonomous agents that learn from human reward

NARCIS (Netherlands)

Li, Guangliang

2016-01-01

In the future, autonomous agents will operate in human inhabited environments in many real world applications and become an integral part of human’s daily lives. Therefore, when autonomous agents enter into the real world, they need to adapt to many novel, dynamic and complex situations that cannot

A basic research of gadolinium hydrogen [alpha], [alpha]', [alpha]'', [alpha]'''-tetramethly- 1,4,7,10-tetraazacyclododecane- 1,4,7,10-tetraacetate with high complex stability as a contrast agent for MRI

Energy Technology Data Exchange (ETDEWEB)

Seri, Shigemi; Hashiguchi, Yuji; Kubomura, Kan; Abe, Yukiko; Iguchi, Toshio; Iwai, Kumiko [Nihon Medi-Physics Co., Ltd., Sodegaura, Chiba (Japan); Watanabe, Tokuko

1993-05-01

Gadolinium hydrogen [alpha], [alpha]', [alpha]'', [alpha]'''-tetramethyl- 1,4,7,10-tetraazacyclododecane- 1,4,7,10-tetraacetate (abbreviated Gd-DOTMA) was developed as a new contrast agent for magnetic resonance imaging. Our study focused on the evaluation of the pharmaceutical properties as in vivo agent. The new modified process by which Gd-DOTMA was synthesized resulted in high yields of this agent. A high stability constant of 10[sup 26] fro Gd-DOTMA was determined at physiological pH. It is more stable than Gd complex with tetraazacyclododecanetetraacetic acid (which is regarded as the most stable Gd complex). The strong T[sub 1] relaxivities of 4.0 and 3.7 (mM [center dot] s)[sup -1] at 0.5 tesla and 1.5 tesla were measured in the aqueous solution. The osmolarity of 0.5 M solution, dissolved with equal amounts of meglumine as a solubilizer is 1020 mOsmol/kg. This contrasting agent was studied in vivo by using rats as the experimental group. The agent showed strong enhancement of transplanted tumors within the rat population studied. This compound is rapidly excreted by the kidneys, and has a half-life of 26 min in blood. The median lethal dose (LD[sub 50] value) of the stable Gd-DOTMA has a favorable tolerance of over 12.3 mmol/kg. (author).

A basic research of gadolinium hydrogen α, α', α'', α'''-tetramethly- 1,4,7,10-tetraazacyclododecane- 1,4,7,10-tetraacetate with high complex stability as a contrast agent for MRI

International Nuclear Information System (INIS)

Seri, Shigemi; Hashiguchi, Yuji; Kubomura, Kan; Abe, Yukiko; Iguchi, Toshio; Iwai, Kumiko; Watanabe, Tokuko.

1993-01-01

Gadolinium hydrogen α, α', α'', α'''-tetramethyl- 1,4,7,10-tetraazacyclododecane- 1,4,7,10-tetraacetate (abbreviated Gd-DOTMA) was developed as a new contrast agent for magnetic resonance imaging. Our study focused on the evaluation of the pharmaceutical properties as in vivo agent. The new modified process by which Gd-DOTMA was synthesized resulted in high yields of this agent. A high stability constant of 10 26 fro Gd-DOTMA was determined at physiological pH. It is more stable than Gd complex with tetraazacyclododecanetetraacetic acid (which is regarded as the most stable Gd complex). The strong T 1 relaxivities of 4.0 and 3.7 (mM · s) -1 at 0.5 tesla and 1.5 tesla were measured in the aqueous solution. The osmolarity of 0.5 M solution, dissolved with equal amounts of meglumine as a solubilizer is 1020 mOsmol/kg. This contrasting agent was studied in vivo by using rats as the experimental group. The agent showed strong enhancement of transplanted tumors within the rat population studied. This compound is rapidly excreted by the kidneys, and has a half-life of 26 min in blood. The median lethal dose (LD 50 value) of the stable Gd-DOTMA has a favorable tolerance of over 12.3 mmol/kg. (author)

Non-radiological contrast agents (MRI)

International Nuclear Information System (INIS)

Bonnemain, B.; Lautrou, J.; Meyer, D.; Doucet, D.

1987-01-01

Over the past few years, extensive research has been carried out in an attempt to develop contrast agents that could help improve both the performance (acquisition times) and the diagnostic efficacy of Magnetic Resonance Imaging (MRI) techniques. On the basis of physicochemical and pharmacological criteria discussed in this presentation, a few efficacious, well-tolerated compounds could be developed. Two of them, the gadolinium complexes Gd-DOTA and Gd-DTPA, are currently being tried in man. This first generation of contrast agents, which are aspecific markers of the intravascular space, has been shown to have good diagnostic potential in conventional MRI procedures. The diagnostic contribution of these contrast agents will probably be a most essential factor in new MRI techniques using low field strengh or fast imaging sequences [fr

Decentralized Planning for Autonomous Agents Cooperating in Complex Missions

Science.gov (United States)

2010-09-01

is a " lawn mower " search path. The world is divided into N, rectangles, and each agent traverses its own rectangle by sweeping back and forth in a...mission. Furthermore, the random walk never found more than three targets for the 50 missions simulated, as seen in Figure 5-7. The lawn mower search...that both the random walk and the lawn mower search seem to find targets at a linear rate with respect to time, whereas the other four strategies are

Complex systems and networks dynamics, controls and applications

CERN Document Server

Yu, Xinghuo; Chen, Guanrong; Yu, Wenwu

2016-01-01

This elementary book provides some state-of-the-art research results on broad disciplinary sciences on complex networks. It presents an in-depth study with detailed description of dynamics, controls and applications of complex networks. The contents of this book can be summarized as follows. First, the dynamics of complex networks, for example, the cluster dynamic analysis by using kernel spectral methods, community detection algorithms in bipartite networks, epidemiological modeling with demographics and epidemic spreading on multi-layer networks, are studied. Second, the controls of complex networks are investigated including topics like distributed finite-time cooperative control of multi-agent systems by applying homogenous-degree and Lyapunov methods, composite finite-time containment control for disturbed second-order multi-agent systems, fractional-order observer design of multi-agent systems, chaos control and anticontrol of complex systems via Parrondos game and many more. Third, the applications of ...

The role of metal complexes in nuclear reactor decontamination

Energy Technology Data Exchange (ETDEWEB)

Prince, A.A.M.; Raghavan, P.S.; Gopalan, R. [Madras Christian College, Tambaram, Chennai (India); Velmurugan, S.; Narasimhan, S.V. [Bhabha Atomic Research Center (BARC) (IN). Water and Steam Chemistry Lab. (WSCL)

2006-07-15

Chemical decontamination is the process of removal of radioactivity from corrosion products formed on structural materials in the nuclear reactors. These corrosion products cause problems for the operation and maintenance of the plants. Removal of the radioactive contaminants can be achieved by dissolving the oxide from the system surface using organic complexing agents in low concentrations known as dilute chemical decontamination (DCD) formulations. These organic complexing agents attack the oxide surface and form metal complexes, which further accelerate the dissolution process. The stability of the complexes plays an important role in dissolving the radioactive contaminated oxides. In addition, the DCD process is operated through ion exchange resins for the removal of the dissolved metal ions and radioactive nuclides. In the present study, the kinetics of dissolution of various model corrosion products such as magnetite (Fe{sub 3}O{sub 4}), hematite ({alpha}-Fe{sub 2}O{sub 3}) and maghemite ({gamma}-Fe{sub 2}O{sub 3}) have been studied in the presence of complexing agents such as ethylenediaminetetraacetic acid (EDTA), nitrilotriacetic acid (NTA), hydroxyethylethylenediaminepentaacetic acid (HEEDTA), and 2,6 pyridinedicarboxylic acid (PDCA). The reductive roles of metal complexes and organic reducing agents are discussed. (orig.)

Influence of citrate ions as complexing agent for electrodeposition of CuInSe{sub 2} thin films

Energy Technology Data Exchange (ETDEWEB)

Chraibi, F. [Universite Libre de Bruxelles (Belgium). Service de Sciences des Materiaux et Electrochimie; Universite Mohammed 5, Rabat (Morocco). Dept. de Physique; Fahoume, M.; Ennaoui, A. [Universite Mohammed 5, Rabat (Morocco). Dept. de Physique; Delplancke, J.L. [Universite Libre de Bruxelles (Belgium). Service de Sciences des Materiaux et Electrochimie

2001-08-16

The preparation of CuInSe{sub 2} thin films by electrodeposition is studied. The effect of sodium citrate (Na{sub 3}C{sub 6}H{sub 5}O{sub 7}) as complexing agent on the electrodeposition of pure copper, indium, selenium and of their ternary alloy is emphasized. Cathodic shifts of the copper and selenium electrodeposition potentials with increasing citrate concentration are observed. On the contrary, the presence of citrate in the electrolyte does not change the indium electrodeposition potential but improves its crystallinity. The surface morphology and the composition of the deposited films are characterized by scanning electron microscopy (SEM). The texture of the deposits and their compositions are analyzed by X-ray diffraction. The formation of CuInSe{sub 2} films with a chalcopyrite structure and good stoichiometry is observed. (orig.)

The Growing Complexity of Cancer Cell Response to DNA-Damaging Agents: Caspase 3 Mediates Cell Death or Survival?

Directory of Open Access Journals (Sweden)

Razmik Mirzayans

2016-05-01

Full Text Available It is widely stated that wild-type p53 either mediates the activation of cell cycle checkpoints to facilitate DNA repair and promote cell survival, or orchestrates apoptotic cell death following exposure to cancer therapeutic agents. This reigning paradigm has been challenged by numerous discoveries with different human cell types, including solid tumor-derived cell lines. Thus, activation of the p53 signaling pathway by ionizing radiation and other DNA-damaging agents hinders apoptosis and triggers growth arrest (e.g., through premature senescence in some genetic backgrounds; such growth arrested cells remain viable, secrete growth-promoting factors, and give rise to progeny with stem cell-like properties. In addition, caspase 3, which is best known for its role in the execution phase of apoptosis, has been recently reported to facilitate (rather than suppress DNA damage-induced genomic instability and carcinogenesis. This observation is consistent with an earlier report demonstrating that caspase 3 mediates secretion of the pro-survival factor prostaglandin E2, which in turn promotes enrichment of tumor repopulating cells. In this article, we review these and related discoveries and point out novel cancer therapeutic strategies. One of our objectives is to demonstrate the growing complexity of the DNA damage response beyond the conventional “repair and survive, or die” hypothesis.

Coordinating Decentralized Learning and Conflict Resolution across Agent Boundaries

Science.gov (United States)

Cheng, Shanjun

2012-01-01

It is crucial for embedded systems to adapt to the dynamics of open environments. This adaptation process becomes especially challenging in the context of multiagent systems because of scalability, partial information accessibility and complex interaction of agents. It is a challenge for agents to learn good policies, when they need to plan and…

Copper complexes as 'radiation recovery' agents

International Nuclear Information System (INIS)

Sorenson, J.R.J.

1989-01-01

Copper and its compounds have been used for their remedial effects since the beginning of recorded history. As early as 3000 BC the Egyptians used copper as an antiseptic for healing wounds and to sterilise drinking water; and later, ca 1550 BC, the Ebers Papyrus reports the use of copper acetate, copper sulphate and pulverised metallic copper for the treatment of eye infections. These historical uses of copper and its compounds are particularly interesting in the light of modern evidence concerning the use of certain copper complexes for the treatment of radiation sickness and more recently as an adjunct to radiotherapy for cancer patients. (author)

Gadolinium Complex of 1,4,7,10-Tetraazacyclododecane-N,N',N'',N'''-1,4,7-trisacetic Acid (DO3A) Conjugate of Tranexamates: A Quest for a Liver-specific Magnetic Resonance Imaging Contrast Agent

International Nuclear Information System (INIS)

Nam, Kisoo; Jeong, Hyunjeong; Kim, Heekyung; Choi, Garam; Chang, Yongmin; Kim, Taejeong; Suh, Kyungjin

2014-01-01

The work is directed toward the synthesis of a series of DO3A conjugates of tranexamates (1c-e) and their Gd complexes (2c-e) for use as a liver-specific MRI CA. All these complexes show thermodynamic and kinetic stabilities comparable to those of structurally related clinical agents such as Dotarem. Their R 1 relaxivities also compare well with those of commercial agent, ranging 3.68-4.84 mM -1 s -1 . In vivo MR images of mice with 2a-e reveal that only 2a exhibits liver-specificity. Although 2b and 2c show strong enhancement in liver, yet no bile-excretion is observed to be termed as a liver-specific agent. The rest behaves much like ordinary ECF CAs like Dotarem. The new series possess no toxicity to be employed in vivo

A multi-agent design for a pressurized water reactor (P.W.R.) control system; Modelisation multi-agents pour la conduite d'un reacteur a eau sous pression (REP)

Energy Technology Data Exchange (ETDEWEB)

Aimar-Lichtenberger, M. [Paris-11 Univ., 91 - Orsay (France)

1999-01-01

This PhD work is in keeping with the complex industrial process control. The starting point is the analysis of control principles in a Pressurized Water Reactor (P.W.R). In order to cope with the limits of the present control procedures, a new control organisation by objectives and means is defined. This functional organisation is based on the state approach and is characterized by the parallel management of control functions to ensure the continuous control of the installation essential variables. With regard to this complex system problematic, we search the most adapted computer modeling. We show that a multi-agent system approach brings an interesting answer to manage the distribution and parallelism of control decisions and tasks. We present a synthetic study of multi-agent systems and their application fields.The choice of a multi-agent approach proceeds with the design of an agent model. This model gains experiences from other applications. This model is implemented in a computer environment which combines the mechanisms of an object language with Prolog. We propose in this frame a multi-agent modeling of the control system where each function is represented by an agent. The agents are structured in a hierarchical organisation and deal with different abstraction levers of the problem. Following a prototype process, the validation is realized by an implementation and by a coupling to a reactor simulator. The essential contributions of an agent approach turn on the mastery of the system complexity, the openness, the robustness and the potentialities of human-machine cooperation. (author)

DNA Damage Induced by Alkylating Agents and Repair Pathways

Science.gov (United States)

Kondo, Natsuko; Takahashi, Akihisa; Ono, Koji; Ohnishi, Takeo

2010-01-01

The cytotoxic effects of alkylating agents are strongly attenuated by cellular DNA repair processes, necessitating a clear understanding of the repair mechanisms. Simple methylating agents form adducts at N- and O-atoms. N-methylations are removed by base excision repair, AlkB homologues, or nucleotide excision repair (NER). O6-methylguanine (MeG), which can eventually become cytotoxic and mutagenic, is repaired by O6-methylguanine-DNA methyltransferase, and O6MeG:T mispairs are recognized by the mismatch repair system (MMR). MMR cannot repair the O6MeG/T mispairs, which eventually lead to double-strand breaks. Bifunctional alkylating agents form interstrand cross-links (ICLs) which are more complex and highly cytotoxic. ICLs are repaired by complex of NER factors (e.g., endnuclease xeroderma pigmentosum complementation group F-excision repair cross-complementing rodent repair deficiency complementation group 1), Fanconi anemia repair, and homologous recombination. A detailed understanding of how cells cope with DNA damage caused by alkylating agents is therefore potentially useful in clinical medicine. PMID:21113301

Interaction of chelating agents with cadmium in mice and rats

International Nuclear Information System (INIS)

Eybl, V.; Sykora, J.; Koutensky, J.; Caisova, D.; Schwartz, A.; Mertl, F.

1984-01-01

The influence of several chelating agents (CaDTPA, ZnDTPA, CaEDTA, ZnEDTA, DMSA, D-penicillamine and DMPS, DMP and DDC) on the acute toxicity of CdCl 2 and on the whole body retention and tissue distribution of cadmium after the IV application of /sup 115mCdCl 2 was compared in mice. The chelating agents were applied immediately after the application of cadmium. CaDTPA, ZnDTPA and DMSA appeared to be the most effective antidotes. However, DMSA increased the amount of cadmium retained in kidneys. The treatement of cadmium-poisoned mice with the combination of DMSA (IP) and ZnDTPA (SC) (all the compounds were injected in equimolar dose) decreased the toxicity of cadmium more than treatment with one chelating agents (given in a 2:1 dose). However, by studying the effect of these chelating agents and their combination application of the antidotes showed little or no improvement over the results obtained with the most effective of the individual components. In the urine of rats injected with CdCl 2 and treated with the chelating agents (CaDTPA, ZnDTPA, DMSA), the presence of cadmium complexes was demonstrated. The formation of mixed ligand chelates in vivo was not proved. Experiments in mice given a single injection of /sup 115m/Cd-labeled Cd complexes of DMPS, DMSA and DTPA showed a high retention of cadmium in the organisms after the IV application of CdDMPS and CdDMSA complexes

Synthesis, characterization and in vivo evaluation of [(62)Zn]-benzo-δ-sultam complex as a possible pet imaging agent.

Science.gov (United States)

Ghandi, Mehdi; Feizi, Shahzad; Ziaie, Farhood; Fazaeli, Yousef; Notash, Behrooz

2014-11-01

The development of a new tracer based on the cyclic sulfonamides (sultams) was investigated. 3-(Methoxy-phenyl-methyl)-1,6-dimethyl-1H benzo[c][1,2] thiazine 2,2-dioxide (benzo-δ-sultam) was synthesized and characterized by elemental analysis, FT-IR spectroscopy and single crystal X-ray structure determination. The prepared cyclic sulfonamide was labeled with non-commercial (62)Zn radioisotope for fast in vivo targeting and Coincidence imaging purposes (radiochemical purity 97 % ITLC, 96 % HPLC, specific activity 20-23 GBq/mmol). In vivo biodistribution of the final complex was investigated in Sprague Dawley(®) rats bearing fibro sarcoma tumor after 2, 4 and 8 h post injection and compared with free Zn(+2) cation. Using instant paper chromatography method, the physicochemical properties of labeled compounds were found sufficiently stable in organic phases, e.g. a human serum, to be reliably used in bioapplications. The complex exhibited a rapid as well as high tumor uptake (tumor to blood ratio 4.38 and tumor to muscle ratio 9.63) resulting in an efficient tumor targeting agent.

Use of 2-mercaptopyridine for the determination of alkylating agents in complex matrices: application to dimethyl sulfate.

Science.gov (United States)

Hoogerheide, J G; Scott, R A

2005-01-30

A rapid and sensitive method for the determination of alkylating agents in complex reaction mixtures was developed and characterized. Analyses are based on the alkylation of 2-mercaptopyridine by the analyte; the derivative is separated by RP-HPLC and measured by fluorescence detection. When applied to the determination of dimethyl sulfate, the method is linear over four orders of magnitude: 0.01-10mugmL(-1). By using recrystallized 2-mercaptopyridine, quantitation limits of 10ngmL(-1) can be achieved. Precision of the assay is 2% R.S.D. in the 1-10mugmL(-1) range and about 15% R.S.D. at 10ngmL(-1). Studies on the pH dependence of the derivatization reaction were key to minimizing interference from the dimethyl sulfate degradation product, monomethyl sulfate, in quenched reaction samples.

Evolutionary game theory using agent-based methods.

Science.gov (United States)

Adami, Christoph; Schossau, Jory; Hintze, Arend

2016-12-01

Evolutionary game theory is a successful mathematical framework geared towards understanding the selective pressures that affect the evolution of the strategies of agents engaged in interactions with potential conflicts. While a mathematical treatment of the costs and benefits of decisions can predict the optimal strategy in simple settings, more realistic settings such as finite populations, non-vanishing mutations rates, stochastic decisions, communication between agents, and spatial interactions, require agent-based methods where each agent is modeled as an individual, carries its own genes that determine its decisions, and where the evolutionary outcome can only be ascertained by evolving the population of agents forward in time. While highlighting standard mathematical results, we compare those to agent-based methods that can go beyond the limitations of equations and simulate the complexity of heterogeneous populations and an ever-changing set of interactors. We conclude that agent-based methods can predict evolutionary outcomes where purely mathematical treatments cannot tread (for example in the weak selection-strong mutation limit), but that mathematics is crucial to validate the computational simulations. Copyright © 2016 Elsevier B.V. All rights reserved.

Agent-based Simulation of the Maritime Domain

Directory of Open Access Journals (Sweden)

O. Vaněk

2010-01-01

Full Text Available In this paper, a multi-agent based simulation platform is introduced that focuses on legitimate and illegitimate aspects of maritime traffic, mainly on intercontinental transport through piracy afflicted areas. The extensible architecture presented here comprises several modules controlling the simulation and the life-cycle of the agents, analyzing the simulation output and visualizing the entire simulated domain. The simulation control module is initialized by various configuration scenarios to simulate various real-world situations, such as a pirate ambush, coordinated transit through a transport corridor, or coastal fishing and local traffic. The environmental model provides a rich set of inputs for agents that use the geo-spatial data and the vessel operational characteristics for their reasoning. The agent behavior model based on finite state machines together with planning algorithms allows complex expression of agent behavior, so the resulting simulation output can serve as a substitution for real world data from the maritime domain.

Copper(II)-bis(thiosemicarbazonato) complexes as anti-chlamydial agents.

Science.gov (United States)

Marsh, James W; Djoko, Karrera Y; McEwan, Alastair G; Huston, Wilhelmina M

2017-09-29

Lipophilic copper (Cu)-containing complexes have shown promising antibacterial activity against a range of bacterial pathogens. To examine the susceptibility of the intracellular human pathogen Chlamydia trachomatis to copper complexes containing bis(thiosemicarbazone) ligands [Cu(btsc)], we tested the in vitro effect of CuII-diacetyl- and CuII-glyoxal-bis[N(4)-methylthiosemicarbazonato] (Cu(atsm) and Cu(gtsm), respectively) on C. trachomatis. Cu(atsm) and to a greater extent, Cu(gtsm), prevented the formation of infectious chlamydial progeny. Impacts on host cell viability and respiration were also observed in addition to the Chlamydia impacts. This work suggests that copper-based complexes may represent a new lead approach for future development of new therapeutics against chlamydial infections, although host cell impacts need to be fully explored. © FEMS 2017. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Multiscale agent-based cancer modeling.

Science.gov (United States)

Zhang, Le; Wang, Zhihui; Sagotsky, Jonathan A; Deisboeck, Thomas S

2009-04-01

Agent-based modeling (ABM) is an in silico technique that is being used in a variety of research areas such as in social sciences, economics and increasingly in biomedicine as an interdisciplinary tool to study the dynamics of complex systems. Here, we describe its applicability to integrative tumor biology research by introducing a multi-scale tumor modeling platform that understands brain cancer as a complex dynamic biosystem. We summarize significant findings of this work, and discuss both challenges and future directions for ABM in the field of cancer research.

Modeling of a production system using the multi-agent approach

Science.gov (United States)

Gwiazda, A.; Sękala, A.; Banaś, W.

2017-08-01

The method that allows for the analysis of complex systems is a multi-agent simulation. The multi-agent simulation (Agent-based modeling and simulation - ABMS) is modeling of complex systems consisting of independent agents. In the case of the model of the production system agents may be manufactured pieces set apart from other types of agents like machine tools, conveyors or replacements stands. Agents are magazines and buffers. More generally speaking, the agents in the model can be single individuals, but you can also be defined as agents of collective entities. They are allowed hierarchical structures. It means that a single agent could belong to a certain class. Depending on the needs of the agent may also be a natural or physical resource. From a technical point of view, the agent is a bundle of data and rules describing its behavior in different situations. Agents can be autonomous or non-autonomous in making the decision about the types of classes of agents, class sizes and types of connections between elements of the system. Multi-agent modeling is a very flexible technique for modeling and model creating in the convention that could be adapted to any research problem analyzed from different points of views. One of the major problems associated with the organization of production is the spatial organization of the production process. Secondly, it is important to include the optimal scheduling. For this purpose use can approach multi-purposeful. In this regard, the model of the production process will refer to the design and scheduling of production space for four different elements. The program system was developed in the environment NetLogo. It was also used elements of artificial intelligence. The main agent represents the manufactured pieces that, according to previously assumed rules, generate the technological route and allow preprint the schedule of that line. Machine lines, reorientation stands, conveyors and transport devices also represent the

Diphosphonic Acid (HEDP) Complex As A, Bone Pain Palliative Agent

International Nuclear Information System (INIS)

H G, Adang; Mutalib, A; Bagiawati, Sri; S, Evi; Aguawarini, Sri; Abidin

2003-01-01

Bone pain is a common complication for patient with bone metastases from prostate, breasts, lung and renal cancers. The systemic treatment of metastatic bone cancers can be done by using analgesic drug therapy, hormonal therapy, chemotherapy, narcotic (morphine) and radiopharmaceuticals. Samarium-153 EDTMP is one of the most widely used radiopharmaceutical for the treatment of metallics bone pain. Preparation and quality control of 186 Re-HEDP have been carried out. Radiochemical purity was analysed using paper chromatography and resulted in maximum yields more than 90 % . Complexes quite were stable for 3 days when stored at 4 o C. Rhenium-186 HEDP complex contents in the blood reach optimum activity after 5 minutes and decrease drastically at 24 hours post injection. The complex showed major renal clearance up to 41 % as perrhenate ion within 24 hours after injection, Biodistribution pattern of the injected complex in mice indicates that the accumulated optimum activity in the bone was obtained between 2 - 24 hours post injection, Sterility and pyrogenicity test indicated that the complex were sterile and pyrogen free

Measurement and Evaluation of Animated Pedagogical Agents and Their Use in Training

National Research Council Canada - National Science Library

Hosie, Thomas

2004-01-01

... on-screen agents that speak in a human voice rather than a machine-synthesized voice; (b) an image effect, an agent's image fosters learning when it is programmed to explain complex visual information aurally; (c...

Antimicrobial evaluation of new metallic complexes with xylitol active against P. aeruginosa and C. albicans: MIC determination, post-agent effect and Zn-uptake.

Science.gov (United States)

Santi, E; Facchin, G; Faccio, R; Barroso, R P; Costa-Filho, A J; Borthagaray, G; Torre, M H

2016-02-01

Xylitol (xylH5) is metabolized via the pentose pathway in humans, but it is unsuitable as an energy source for many microorganisms where it produces a xylitol-induced growth inhibition and disturbance in protein synthesis. For this reason, xylitol is used in the prophylaxis of several infections. In the search of better antimicrobial agents, new copper and zinc complexes with xylitol were synthesized and characterized by analytical and spectrosco pic methods: Na2[Cu3(xylH−4)2]·NaCl·4.5H2O (Cu-xyl) and [Zn4(xylH−4)2(H2O)2]·NaCl·3H2O (Zn-xyl). Both copper and zinc complexes presented higher MIC against Pseudomona aeruginosa than the free xylitol while two different behaviors were found against Candida albicans depending on the complex. The growth curves showed that Cu-xyl presented lower activity than the free ligand during all the studied period. In the case of Znxyl the growth curves showed that the inhibition of the microorganism growth in the first stage was equivalent to that of xylitol but in the second stage (after 18 h) Zn-xyl inhibited more. Besides, the PAE (post agent effect)obtained for Zn-xyl and xyl showed that the recovery from the damage of microbial cells had a delay of 14 and 13 h respectively. This behavior could be useful in prophylaxis treatments for infectious diseases where it is important that the antimicrobial effect lasts longer. With the aim to understand the microbiological activities the analysis of the particle size, lipophilicity and Zn uptake was performed.

Organically complexed copper, zinc, and chelating agents in the rivers of Western Puerto Rico

International Nuclear Information System (INIS)

Montgomery, J.R.; Echevarria, J.E.

1975-01-01

The method for determining soluble chelators gives their concentration in copper-equivalent chelating capacity units in fresh or slightly brackish (less than 3 percent salinity) water. The mean concentration of chelators in the Rio Guanajibo for December 1973 and January 1974 was 0.4 mg of copper per liter of water (N = 21, SD = 0.2) and for February 1974, 0.9 mg/liter (N = 8, SD = 0.4). The combined mean for the Rio Anasco and Culebrinas was 0.5 mg/liter (N = 7, SD = 0.4) in January and February 1974. The mean concentration of ionic copper was 0.5 μg/liter (N = 7, SD = 0.6) and of ionic zinc, 0.2 μg/liter (N = 8, SD = 0.1) in the Rio Guanajibo from November 1972 to February 1973. The concentration of organically bound copper was 0.3 μ/liter (N = 7, SD = 0.2) and that of organically bound zinc was 0.6 μg/liter (N = 8, SD = 0.6); this indicates that there was more than a sufficient quantity of chelator available in the river to complex all the soluble copper. The presence of a high ratio of Ca 2+ to Cu 2+ probably prevents the formation of larger concentrations of organically complexed copper. The mean concentration of chelating agents in the Guanajibo River seems to be directly related to the increased organic input from municipalities and a sugar mill. The concentration of chelators in tropical rivers appears to be higher than that found in Canadian lakes. The mean concentration for particulate organic carbon (POC) was 3653 μg atoms/liter (SD = 3653, N = 29). The dissolved reactive phosphate (DRP) ranged from a mean of 1.1 μg atom/liter. No significant correlation could be found between POC, DRP, and the concentration of chelators

Brownian Agents and Active Particles: Collective Dynamics in the Natural and Social Sciences

International Nuclear Information System (INIS)

McKane, Alan

2003-01-01

This is a book about the modelling of complex systems and, unlike many books on this subject, concentrates on the discussion of specific systems and gives practical methods for modelling and simulating them. This is not to say that the author does not devote space to the general philosophy and definition of complex systems and agent-based modelling, but the emphasis is definitely on the development of concrete methods for analysing them. This is, in my view, to be welcomed and I thoroughly recommend the book, especially to those with a theoretical physics background who will be very much at home with the language and techniques which are used. The author has developed a formalism for understanding complex systems which is based on the Langevin approach to the study of Brownian motion. This is a mesoscopic description; details of the interactions between the Brownian particle and the molecules of the surrounding fluid are replaced by a randomly fluctuating force. Thus all microscopic detail is replaced by a coarse-grained description which encapsulates the essence of the interactions at the finer level of description. In a similar way, the influences on Brownian agents in a multi-agent system are replaced by stochastic influences which sum up the effects of these interactions on a finer scale. Unlike Brownian particles, Brownian agents are not structureless particles, but instead have some internal states so that, for instance, they may react to changes in the environment or to the presence of other agents. Most of the book is concerned with developing the idea of Brownian agents using the techniques of statistical physics. This development parallels that for Brownian particles in physics, but the author then goes on to apply the technique to problems in biology, economics and the social sciences. This is a clear and well-written book which is a useful addition to the literature on complex systems. It will be interesting to see if the use of Brownian agents becomes

Characterization of Cu–Ni nanostructured alloys obtained by a chemical route. Influence of the complexing agent content in the starting solution

Energy Technology Data Exchange (ETDEWEB)

Carreras, Alejo C., E-mail: acarreras@famaf.unc.edu.ar [Instituto de Física Enrique Gaviola (IFEG), Facultad de Matemática, Astronomía y Física, Universidad Nacional de Córdoba—CONICET, Medina Allende s/n, Ciudad Universitaria, 5016 Córdoba (Argentina); Cangiano, María de los A.; Ojeda, Manuel W.; Ruiz, María del C. [Instituto de Investigaciones en Tecnología Qumica (INTEQUI), Facultad de Química, Bioquímica y Farmacia, Universidad Nacional de San Luis—CONICET, Chacabuco y Pedernera, 5700 San Luis (Argentina)

2015-03-15

The influence of the amount of complexing agent added to the starting solution on the physicochemical properties of Cu–Ni nanostructured alloys obtained through a chemical route, was studied. For this purpose, three Cu–Ni nanoalloy samples were synthesized by a previously developed procedure, starting from solutions with citric acid to metal molar ratios (C/Me) of 0.73, 1.00 and 1.50. The synthesis technique consisted in preparing a precursor via the citrate-gel method, and carrying out subsequent thermal treatments in controlled atmospheres. Sample characterization was performed by scanning electron microscopy, X-ray microanalysis, X-ray diffraction, transmission electron microscopy, X-ray nanoanalysis and electron diffraction. In the three cases, copper and nickel formed a solid solution with a Cu/Ni atomic ratio close to 50/50, and free of impurities inside the crystal structure. The citric acid content of the starting solution proved to have an important influence on the morphology, size distribution, porosity, and crystallinity of the Cu–Ni alloy microparticles obtained, but a lesser influence on their chemical composition. The molar ratio C/Me = 1.00 resulted in the alloy with the Cu/Ni atomic ratio closest to 50/50. - Highlights: • We synthesize Cu–Ni nanoalloys by a chemical route based on the citrate-gel method. • We study the influence of the complexing agent content of the starting solution. • We characterize the samples by electron microscopy and X-ray techniques. • Citric acid influences the shape, size, porosity and crystallinity of the alloys.

On the formal analysis of the dynamics of simulated agent societies

NARCIS (Netherlands)

Popova, V.; Eiben, A.E.; Jonker, C.M.; Schut, M.C.

2007-01-01

To analyze emergent behavior, a formal framework is needed to characterize the structure and dynamics of complex interaction-based multi-agent systems. We introduce an extension of an existing agent testbed for artificial societies making it possible to formally analyze the dynamics of the simulated

Modelling the Dynamics of Intracellular Processes as an Organisation of Multiple Agents

NARCIS (Netherlands)

Bosse, T.; Jonker, C.M.; Treur, J.; Armano, G.; Merelli, E.; Denzinger, J.; Martin, A.; Miles, S.; Tianfield, H.; Unland, R.

2005-01-01

This paper explores how the dynamics of complex biological processes can be modeled as an organisation of multiple agents. This modelling perspective identifies organisational structure occurring in complex decentralised processes and handles complexity of the analysis of the dynamics by structuring

In vitro evaluation of the cyto-genotoxic potential of Ruthenium(II) SCAR complexes: a promising class of antituberculosis agents.

Science.gov (United States)

De Grandis, Rone Aparecido; Resende, Flávia Aparecida; da Silva, Monize Martins; Pavan, Fernando Rogério; Batista, Alzir Azevedo; Varanda, Eliana Aparecida

2016-03-01

Tuberculosis is a top infectious disease killer worldwide, caused by the bacteria Mycobacterium tuberculosis. Increasing incidences of multiple drug-resistance (MDR) strains are emerging as one of the major public health threats. However, the drugs in use are still incapable of controlling the appalling upsurge of MDR. In recent years a marked number of research groups have devoted their attention toward the development of specific and cost-effective antimicrobial agents against targeted MDR-Tuberculosis. In previous studies, ruthenium(II) complexes (SCAR) have shown a promising activity against MDR-Tuberculosis although few studies have indeed considered ruthenium toxicity. Therefore, within the preclinical requirements, we have sought to determine the cyto-genotoxicity of three SCAR complexes in this present study. The treatment with the SCARs induced a concentration-dependent decrease in cell viability in CHO-K1 and HepG2 cells. Based on the clonogenic survival, SCAR 5 was found to be more cytotoxic while SCAR 6 exhibited selectivity action on tumor cells. Although SCAR 4 and 5 did not indicate any mutagenic activity as evidenced by the Ames and Cytokinesis block micronucleus cytome assays, the complex SCAR 6 was found to engender a frameshift mutation detected by Salmonella typhimurium in the presence of S9. Similarly, we observed a chromosomal damage in HepG2 cells with significant increases of micronuclei and nucleoplasmic bridges. These data indicate that SCAR 4 and 5 complexes did not show genotoxicity in our models while SCAR 6 was considered mutagenic. This study presented a comprehensive genotoxic evaluation of SCAR complexes were shown to be genotoxic in vitro. All in all, further studies are required to fully elucidate how the properties can affect human health. Copyright © 2016 Elsevier B.V. All rights reserved.

Intelligent Design of Nano-Scale Molecular Imaging Agents

Directory of Open Access Journals (Sweden)

Takeaki Ozawa

2012-12-01

Full Text Available Visual representation and quantification of biological processes at the cellular and subcellular levels within living subjects are gaining great interest in life science to address frontier issues in pathology and physiology. As intact living subjects do not emit any optical signature, visual representation usually exploits nano-scale imaging agents as the source of image contrast. Many imaging agents have been developed for this purpose, some of which exert nonspecific, passive, and physical interaction with a target. Current research interest in molecular imaging has mainly shifted to fabrication of smartly integrated, specific, and versatile agents that emit fluorescence or luminescence as an optical readout. These agents include luminescent quantum dots (QDs, biofunctional antibodies, and multifunctional nanoparticles. Furthermore, genetically encoded nano-imaging agents embedding fluorescent proteins or luciferases are now gaining popularity. These agents are generated by integrative design of the components, such as luciferase, flexible linker, and receptor to exert a specific on–off switching in the complex context of living subjects. In the present review, we provide an overview of the basic concepts, smart design, and practical contribution of recent nano-scale imaging agents, especially with respect to genetically encoded imaging agents.

Technetium SPECT agents for imaging heart and brain

International Nuclear Information System (INIS)

Linder, K.E.

1990-01-01

One major goal of radiopharmaceutical research has been the development of technetium-based perfusion tracers for SPECT imaging of the heart and brain. The recent clinical introduction of the technetium complexes HM-PAO, ECD and DMG-2MP for brain imaging, and of CDO-MEB and MIBI for heart imaging promises to revolutionize the field of nuclear medicine. All of these agents appear to localize in the target tissue in proportion to blood flow, but their mechanisms of localization and/or retention may differ quite widely. In this talk, a survey of the new technetium SPECT agents will be presented. The inorganic and biological chemistry of these complexes, mechanisms of uptake and retention, QSAR studies, and potential clinical applications are discussed

Interaction of chelating agents with cadmium in mice and rats.

Science.gov (United States)

Eybl, V; Sýkora, J; Koutenský, J; Caisová, D; Schwartz, A; Mertl, F

1984-01-01

The influence of several chelating agents (CaDTPA, ZnDTPA, CaEDTA, ZnEDTA, DMSA, D-penicillamine and DMPS, DMP and DDC) on the acute toxicity of CdCl2 and on the whole body retention and tissue distribution of cadmium after the IV application of 115mCdCl2 was compared in mice. The chelating agents were applied immediately after the application of cadmium. CaDTPA, ZnDTPA and DMSA appeared to be the most effective antidotes. However, DMSA increased the amount of cadmium retained in kidneys. The treatment of cadmium-poisoned mice with the combination of DMSA (IP) and ZnDTPA (SC) (all the compounds were injected in equimolar dose) decreased the toxicity of cadmium more than treatment with one chelating agents (given in a 2:1 dose). However, by studying the effect of these chelating agents and their combination of the retention and distribution of Cd in mice, it was demonstrated that the combined application of the antidotes showed little or no improvement over the results obtained with the most effective of the individual components. In the urine of rats injected with CdCl2 and treated with the chelating agents (CaDTPA, ZnDTPA, DMSA), the presence of cadmium complexes was demonstrated. The formation of mixed ligand chelates in vivo was not proved. Experiments in mice given a single injection of 115mCd-labeled Cd complexes of DMPS, DMSA and DTPA showed a high retention of cadmium in the organisms after the IV application of CdDMPS and CdDMSA complexes. PMID:6734561

Complexes of technetium-99m with tetrapeptides, a new class of 99mTc-labelled agents

International Nuclear Information System (INIS)

Vanbilloen, Hubert P.; Bormans, Guy M.; Roo, Michel J. de; Verbruggen, Alfons M.

1995-01-01

is concluded that tetrapeptides are an interesting group of technetium complexing agents which can easily be labelled with 99m Tc at room temperature in alkaline medium. This class offers the possibility of a wide variety of derivatives, just by substituting one or more amino acids. This group of ligands thus opens a new research field of 99m Tc-complexes with potential usefulness in several areas

Fundamentals of Agent Perception and Attention Modelling

DEFF Research Database (Denmark)

Peters, Christopher; Castellano, Ginevra; Rehm, Matthias

2011-01-01

Perception and attention mechanisms are of great importance for entities situated within complex dynamic environments. With roles extending greatly beyond passive information services about the external environment, such mechanisms actively prioritise, augment and expedite information to ensure t...... agents can achieve a more substantial connection with their environment for the purposes of reacting, planning, decision making and, ultimately, behaving.......Perception and attention mechanisms are of great importance for entities situated within complex dynamic environments. With roles extending greatly beyond passive information services about the external environment, such mechanisms actively prioritise, augment and expedite information to ensure...... that the potentially relevant is made available so appropriate action can take place. Here, we describe the rationale behind endowing artificial entities, or virtual agents, with real-time perception and attention systems. We cover the fundamentals of designing and building such systems. Once equipped, the resulting...

Inventories of organic materials and complexing agents in intermediate-level long-lived parcels (Report PNGMDR 2013-2015)

International Nuclear Information System (INIS)

2014-01-01

This report presents an inventory of organic materials and of complexing agents they may produce within parcels of alpha wastes which are to be produced or are being currently produced. The report proposes the results of campaigns of measurements of degassing, and comparison with results of modelling studies. The assessment of degassing rates of parcels of alpha wastes is completed by an assessment of hydrogen produced by radiolysis of interstitial water within the concrete container. Thus, after a presentation of the main parcels used by the CEA for intermediate-level long-lived wastes, and of an inventory of wastes containing organic materials, this report describes the consequences of radiolysis on polymers, and describes the objectives of R and D studies. It reports measurements and presents simulation tools for heterogeneous wastes, homogeneous wastes, production of water-soluble degradation products, and transfer and adsorption of these products in the storage site argillite

Effects of a Pedagogical Agent's Emotional Expressiveness on Learner Perceptions

Science.gov (United States)

Romero, Enilda J.; Watson, Ginger S.

2012-01-01

The use of animated pedagogical agents or avatars in instruction has lagged behind their use in entertainment. This is due in part to the cost and complexity of development and implementation of agents in educational settings, but also results from a lack of research to understand how emotions from animated agents influence instructional effectiveness. The phenomenological study presented here assesses the perceptions of eight learners interacting with low and high intensity emotionally expressive pedagogical agents in a computer-mediated environment. Research methods include maximum variation and snowball sampling with random assignment to treatment. The resulting themes incorporate perceptions of importance, agent humanness, enjoyment, implementation barriers, and suggested improvements. Design recommendations and implications for future research are presented.

Complexes formed by cadmium and chelating agents in plants

International Nuclear Information System (INIS)

Strasdeit, H.; Duhme, A.K.; Johanning, J.

1993-01-01

Measurements of X-ray absorption spectrums and potentiometric titrations yield some information on the basic complexforming properties of phytochelates. Cadmium-phytochelate complexes are extremely variable as regards composition and structure. This is evident from the fact that the metal's coordination environment (sulphur or oxygen coordination) is dependent uopn pH values. At pH values of about 7 it is normal to find Cd(SCys) 4 units. Given the availability of an adequate number of ligands, these are seen to occur as solitary units even in multinucleate complexes. (orig.) [de

99mTc renal tubular function agents: Current status

International Nuclear Information System (INIS)

Eshima, D.; Fritzberg, A.R.; Taylor, A. Jr.

1990-01-01

Orthoiodohippuric (OIH) acid labeled with 131I is a widely used renal radiopharmaceutical agent and has been the standard radiopharmaceutical agent for the measurement of effective renal plasma flow (EPRF). Limitations to the routine clinical use of 131I OIH are related to the suboptimal imaging properties of the 131I radionuclide and its relatively high radiation dose. 123I has been substituted for 131I; however, its high cost and short shelf-life have limited its widespread use. Recent work has centered on the development of a new 99mTc renal tubular function agent, which would use the optimal radionuclidic properties and availability of 99mTc and combine the clinical information provided by OIH. The search for a suitable 99mTc renal tubular function agent has focused on the diamide dithiolate (N2S2), the paraaminohippuric iminodiacetic acid (PAHIDA), and the triamide mercaptide (N3S) donor ligand systems. To date, the most promising 99mTc tubular function agent is the N3S complex: 99mTc mercaptoacetyltriglycine (99mTc MAG3). Studies in animal models in diuresis, dehydration, acid or base imbalance, ischemia, and renal artery stenosis demonstrate that 99mTc MAG3 behaves similarly to 131I OIH. A simple kit formulation is available that yields the 99mTc MAG3 complex in high radiochemical purity. Studies in normal subjects and patients indicate that 99mTc MAG3 is an excellent 99mTc renal tubular agent, but its plasma clearance is only 50% to 60% that of OIH. In an effort to develop an improved 99mTc renal tubular function agent, changes have been made in the core N3S donor ligand system, but to date no agent has been synthesized that is clinically superior to 99mTc MAG3. 61 references

Agent Based Modeling Applications for Geosciences

Science.gov (United States)

Stein, J. S.

2004-12-01

Agent-based modeling techniques have successfully been applied to systems in which complex behaviors or outcomes arise from varied interactions between individuals in the system. Each individual interacts with its environment, as well as with other individuals, by following a set of relatively simple rules. Traditionally this "bottom-up" modeling approach has been applied to problems in the fields of economics and sociology, but more recently has been introduced to various disciplines in the geosciences. This technique can help explain the origin of complex processes from a relatively simple set of rules, incorporate large and detailed datasets when they exist, and simulate the effects of extreme events on system-wide behavior. Some of the challenges associated with this modeling method include: significant computational requirements in order to keep track of thousands to millions of agents, methods and strategies of model validation are lacking, as is a formal methodology for evaluating model uncertainty. Challenges specific to the geosciences, include how to define agents that control water, contaminant fluxes, climate forcing and other physical processes and how to link these "geo-agents" into larger agent-based simulations that include social systems such as demographics economics and regulations. Effective management of limited natural resources (such as water, hydrocarbons, or land) requires an understanding of what factors influence the demand for these resources on a regional and temporal scale. Agent-based models can be used to simulate this demand across a variety of sectors under a range of conditions and determine effective and robust management policies and monitoring strategies. The recent focus on the role of biological processes in the geosciences is another example of an area that could benefit from agent-based applications. A typical approach to modeling the effect of biological processes in geologic media has been to represent these processes in

Using Cognitive Agents to Train Negotiation Skills

Directory of Open Access Journals (Sweden)

Christopher A. Stevens

2018-02-01

Full Text Available Training negotiation is difficult because it is a complex, dynamic activity that involves multiple parties. It is often not clear how to create situations in which students can practice negotiation or how to measure students' progress. Some have begun to address these issues by creating artificial software agents with which students can train. These agents have the advantage that they can be “reset,” and played against multiple times. This allows students to learn from their mistakes and try different strategies. However, these agents are often based on normative theories of how negotiators should conduct themselves, not necessarily how people actually behave in negotiations. Here, we take a step toward addressing this gap by developing an agent grounded in a cognitive architecture, ACT-R. This agent contains a model of theory-of-mind, the ability of humans to reason about the mental states of others. It uses this model to try to infer the strategy of the opponent and respond accordingly. In a series of experiments, we show that this agent replicates some aspects of human performance, is plausible to human negotiators, and can lead to learning gains in a small-scale negotiation task.

Using Cognitive Agents to Train Negotiation Skills.

Science.gov (United States)

Stevens, Christopher A; Daamen, Jeroen; Gaudrain, Emma; Renkema, Tom; Top, Jakob Dirk; Cnossen, Fokie; Taatgen, Niels A

2018-01-01

Training negotiation is difficult because it is a complex, dynamic activity that involves multiple parties. It is often not clear how to create situations in which students can practice negotiation or how to measure students' progress. Some have begun to address these issues by creating artificial software agents with which students can train. These agents have the advantage that they can be "reset," and played against multiple times. This allows students to learn from their mistakes and try different strategies. However, these agents are often based on normative theories of how negotiators should conduct themselves, not necessarily how people actually behave in negotiations. Here, we take a step toward addressing this gap by developing an agent grounded in a cognitive architecture, ACT-R. This agent contains a model of theory-of-mind, the ability of humans to reason about the mental states of others. It uses this model to try to infer the strategy of the opponent and respond accordingly. In a series of experiments, we show that this agent replicates some aspects of human performance, is plausible to human negotiators, and can lead to learning gains in a small-scale negotiation task.

Effect of complexing agent TEA: The structural, morphological, topographical and optical properties of Fe{sub x}S{sub x} nano thin films deposited by SILAR technique

Energy Technology Data Exchange (ETDEWEB)

Manikandan, K., E-mail: 1984manikandan@gmail.com [Department of Physics, Anna University BIT Campus, Tiruchirappalli 620 024, Tamilnadu (India); Mani, P. [Department of Physics, Anna University BIT Campus, Tiruchirappalli 620 024, Tamilnadu (India); Surendra Dilip, C. [Department of Chemistry, Anna University BIT Campus, Tiruchirappalli 620 024, Tamilnadu (India); Valli, S. [Department of Physics, M.I.E.T. Arts and Science College, Tiruchirappalli 620 007, Tamilnadu (India); Fermi Hilbert Inbaraj, P.; Joseph Prince, J. [Department of Physics, Anna University BIT Campus, Tiruchirappalli 620 024, Tamilnadu (India)

2014-01-01

Iron sulfide thin films (Fe{sub x}S{sub x}) (x = 0.05 M, 0.10 M, 0.15 M, 0.20 M and 0.25 M) were deposited by SILAR method from equimolar and equivolume aqueous solutions of ferrous nitrate and sodium sulfide with the addition of complexing agent TEA. The structural, morphological and optical characteristics of the films were derived from X-ray diffraction (XRD), scanning electron microscopy (SEM), atomic force microscopy (AFM) and UV–vis spectral techniques. The mixed characteristics (crystalline and amorphous) of the deposited films and the increasing crystalline qualities with the concentrations were understood from the XRD analysis. The grain sizes and roughness of the films were decreases with the increasing concentration and also at the higher concentration films are shown by the same images presence of hexagonal like crystallite structure. The influence of complexing agent TEA on the surface roughness and morphological properties are confirmed by the atomic force microscope (AFM) results. The effect of increasing substrate concentration on the absorption and transmission measurements and its impact on the optical band-gap energy were enumerated from the UV–vis analysis.

Excellent approach to modeling urban expansion by fuzzy cellular automata: agent base model

Science.gov (United States)

Khajavigodellou, Yousef; Alesheikh, Ali A.; Mohammed, Abdulrazak A. S.; Chapi, Kamran

2014-09-01

Recently, the interaction between humans and their environment is the one of important challenges in the world. Landuse/ cover change (LUCC) is a complex process that includes actors and factors at different social and spatial levels. The complexity and dynamics of urban systems make the applicable practice of urban modeling very difficult. With the increased computational power and the greater availability of spatial data, micro-simulation such as the agent based and cellular automata simulation methods, has been developed by geographers, planners, and scholars, and it has shown great potential for representing and simulating the complexity of the dynamic processes involved in urban growth and land use change. This paper presents Fuzzy Cellular Automata in Geospatial Information System and remote Sensing to simulated and predicted urban expansion pattern. These FCA-based dynamic spatial urban models provide an improved ability to forecast and assess future urban growth and to create planning scenarios, allowing us to explore the potential impacts of simulations that correspond to urban planning and management policies. A fuzzy inference guided cellular automata approach. Semantic or linguistic knowledge on Land use change is expressed as fuzzy rules, based on which fuzzy inference is applied to determine the urban development potential for each pixel. The model integrates an ABM (agent-based model) and FCA (Fuzzy Cellular Automata) to investigate a complex decision-making process and future urban dynamic processes. Based on this model rapid development and green land protection under the influences of the behaviors and decision modes of regional authority agents, real estate developer agents, resident agents and non- resident agents and their interactions have been applied to predict the future development patterns of the Erbil metropolitan region.

Diagnosis of multi-agent systems and its application to public administration

NARCIS (Netherlands)

Boer, A.; van Engers, T.; Abramowicz, W.; Maciaszek, L.; Węcel, K.

2011-01-01

In this paper we present a model-based diagnosis view on the complex social systems in which large public administration organizations operate. The purpose of diagnosis as presented in this paper is to identify agent role instances that are not conforming to expectations in a multi-agent system

Evolutionary Agent-Based Simulation of the Introduction of New Technologies in Air Traffic Management

Science.gov (United States)

Yliniemi, Logan; Agogino, Adrian K.; Tumer, Kagan

2014-01-01

Accurate simulation of the effects of integrating new technologies into a complex system is critical to the modernization of our antiquated air traffic system, where there exist many layers of interacting procedures, controls, and automation all designed to cooperate with human operators. Additions of even simple new technologies may result in unexpected emergent behavior due to complex human/ machine interactions. One approach is to create high-fidelity human models coming from the field of human factors that can simulate a rich set of behaviors. However, such models are difficult to produce, especially to show unexpected emergent behavior coming from many human operators interacting simultaneously within a complex system. Instead of engineering complex human models, we directly model the emergent behavior by evolving goal directed agents, representing human users. Using evolution we can predict how the agent representing the human user reacts given his/her goals. In this paradigm, each autonomous agent in a system pursues individual goals, and the behavior of the system emerges from the interactions, foreseen or unforeseen, between the agents/actors. We show that this method reflects the integration of new technologies in a historical case, and apply the same methodology for a possible future technology.

New method for studying the efficiency of chelating agents of the polyamine acid series for internal decontamination

International Nuclear Information System (INIS)

Lafuma, J.; Nenot, J.C.; Morin, M.

1968-01-01

We followed the biological fate of a complex formed on one side with either a rare earth (cerium-144) or a transuranium element (plutonium-239), and on the other side with a chelating agent of the polyamino acid series (EDTA, BAETA, DTPA, TTHA). This method allowed to study: 1 - the in vivo stability of the various complexes and to compare them; 2 - the stability of the complexes as a function of the isotope - chelating agent weight relationships; 3 - the metabolism of the chelating agents resulting in stable complexes, i. e. DTPA and TTHA mainly. This simple method brought out the higher efficiency, of DTPA in chelating rare earths and plutonium and for therapeutic purposes. (authors) [fr

Real-Time Agent-Based Modeling Simulation with in-situ Visualization of Complex Biological Systems: A Case Study on Vocal Fold Inflammation and Healing.

Science.gov (United States)

Seekhao, Nuttiiya; Shung, Caroline; JaJa, Joseph; Mongeau, Luc; Li-Jessen, Nicole Y K

2016-05-01

We present an efficient and scalable scheme for implementing agent-based modeling (ABM) simulation with In Situ visualization of large complex systems on heterogeneous computing platforms. The scheme is designed to make optimal use of the resources available on a heterogeneous platform consisting of a multicore CPU and a GPU, resulting in minimal to no resource idle time. Furthermore, the scheme was implemented under a client-server paradigm that enables remote users to visualize and analyze simulation data as it is being generated at each time step of the model. Performance of a simulation case study of vocal fold inflammation and wound healing with 3.8 million agents shows 35× and 7× speedup in execution time over single-core and multi-core CPU respectively. Each iteration of the model took less than 200 ms to simulate, visualize and send the results to the client. This enables users to monitor the simulation in real-time and modify its course as needed.

Teamcore Project Control of Agent-Based Systems (COABS) Program

National Research Council Canada - National Science Library

Tambe, Milind

2002-01-01

An increasing number of agent-based systems now operate in complex dynamic environments, such as disaster rescue missions, monitoring/surveillance tasks, enterprise integration, and education/training environments...

Modeling agents with a theory of mind : Theory-theory versus simulation theory

NARCIS (Netherlands)

Harbers, M.; Bosch, K. van den; Meyer, J.J.C.

2012-01-01

Virtual training systems with intelligent agents provide an effective means to train people for complex, dynamic tasks like crisis management or firefighting. For successful training, intelligent virtual agents should be able to show believable behavior, adapt their behavior to the trainee’s

method and container for production of diagnostic scanning agents

International Nuclear Information System (INIS)

Ruddock, C.F.

1979-01-01

The pertechnetate ion containing the technetium-99m isotope has limited applications in diagnostic scanning because it does not readily form complexes with materials which locate in specific parts of the body. Stannous salts have been widely used to reduce the pertechnetate to a form which readily complexes with materials. In the present invention, both a container and a more suitable metal reducing agent are discussed for transforming the technetium in pertechnetate for diagnostic scanning use. The vessel contains tin or a tin-containing alloy as a reducing agent for the pertechnetate and a complexant for the reduced technetium; all contents are sterile and dry. The present invention is advantageous over the stannous salts method since (1) problems of stannous salt instability during production, storage and after labelling are eliminated; (2) production procedures are simplified; (3) it is not essential to nitrogen purge vials before sterilisation; (4) it reduces toxicity; (5) the shelf life of diagnostic scanning kits may be dramatically improved; (6) the metal reducing agent may be sterilised by γ-irradiation without deteriorating; (7) the labelling technique can be performed over a wide pH range; and (8) the technique should be unaffected by technetium-99 in the technetium-99m. (U.K.)

A multi-agent design for a pressurized water reactor (P.W.R.) control system

International Nuclear Information System (INIS)

Aimar-Lichtenberger, M.

1999-01-01

This PhD work is in keeping with the complex industrial process control. The starting point is the analysis of control principles in a Pressurized Water Reactor (P.W.R). In order to cope with the limits of the present control procedures, a new control organisation by objectives and means is defined. This functional organisation is based on the state approach and is characterized by the parallel management of control functions to ensure the continuous control of the installation essential variables. With regard to this complex system problematic, we search the most adapted computer modeling. We show that a multi-agent system approach brings an interesting answer to manage the distribution and parallelism of control decisions and tasks. We present a synthetic study of multi-agent systems and their application fields.The choice of a multi-agent approach proceeds with the design of an agent model. This model gains experiences from other applications. This model is implemented in a computer environment which combines the mechanisms of an object language with Prolog. We propose in this frame a multi-agent modeling of the control system where each function is represented by an agent. The agents are structured in a hierarchical organisation and deal with different abstraction levers of the problem. Following a prototype process, the validation is realized by an implementation and by a coupling to a reactor simulator. The essential contributions of an agent approach turn on the mastery of the system complexity, the openness, the robustness and the potentialities of human-machine cooperation. (author)

Brief introductory guide to agent-based modeling and an illustration from urban health research

Directory of Open Access Journals (Sweden)

Amy H. Auchincloss

2015-11-01

Full Text Available Abstract There is growing interest among urban health researchers in addressing complex problems using conceptual and computation models from the field of complex systems. Agent-based modeling (ABM is one computational modeling tool that has received a lot of interest. However, many researchers remain unfamiliar with developing and carrying out an ABM, hindering the understanding and application of it. This paper first presents a brief introductory guide to carrying out a simple agent-based model. Then, the method is illustrated by discussing a previously developed agent-based model, which explored inequalities in diet in the context of urban residential segregation.

Brief introductory guide to agent-based modeling and an illustration from urban health research.

Science.gov (United States)

Auchincloss, Amy H; Garcia, Leandro Martin Totaro

2015-11-01

There is growing interest among urban health researchers in addressing complex problems using conceptual and computation models from the field of complex systems. Agent-based modeling (ABM) is one computational modeling tool that has received a lot of interest. However, many researchers remain unfamiliar with developing and carrying out an ABM, hindering the understanding and application of it. This paper first presents a brief introductory guide to carrying out a simple agent-based model. Then, the method is illustrated by discussing a previously developed agent-based model, which explored inequalities in diet in the context of urban residential segregation.

Synthesis and evaluation of aqueous complexing agents for the Am/Cm separation

International Nuclear Information System (INIS)

Chapron, Simon

2014-01-01

After the reprocessing of uranium, plutonium and eventually neptunium by the PUREX process, the spent fuel is still composed of half of the periodic table. Among these elements, the main responsible for the heat of the wastes is americium. Its reprocessing could allow improving the compactness of deep geological storage of the wastes. Thus the liquid-liquid extraction process called EXAm was developed in order to recover the americium alone. The key step of the process is the Am/Cm separation. An extractant mixture is used with an aqueous complexing agent: TEDGA (N,N',N,N'-tetraethyl-diglycolamide). It allows to enhance the Am/Cm separation by keeping preferentially curium in the aqueous phase, but its structure selectivity relationship is not well known yet. Therefore, the purpose of this thesis is to synthesize and evaluate some structural analogues of TEDGA, in order to better understand the impact of its structure on the Am/Cm selectivity in the EXAm process. During this study, 14 analogues of TEDGA were synthesized and 17 molecules were evaluated in liquid-liquid extraction. Several structural modifications were studied: length and steric hindrance of the N-alkyl chains, size of the spacer, and the introduction of secondary amide functions. This work shows that it is not possible to maintain the ligand in the aqueous phase from tetrabutyl derivatives, and the addition of steric hindrance, or modification of hydrophilicity/lipophilicity balance, systematically decreases the selectivity of ligands. The addition of secondary amide functions (-CONHR) makes the molecules extractable by the solvent (formation of hydrogen bonds with the extractants), therefore they are unsuitable to be used in the EXAm process. The spacer has the main impact on the selectivity: the complexation capacity in high acid medium disappears when it is shortened (malonamide), whereas the ligand has a preference for Am instead of Cm (inversion of selectivity) when it is lengthen

Distributed Cooperation Solution Method of Complex System Based on MAS

Science.gov (United States)

Weijin, Jiang; Yuhui, Xu

To adapt the model in reconfiguring fault diagnosing to dynamic environment and the needs of solving the tasks of complex system fully, the paper introduced multi-Agent and related technology to the complicated fault diagnosis, an integrated intelligent control system is studied in this paper. Based on the thought of the structure of diagnostic decision and hierarchy in modeling, based on multi-layer decomposition strategy of diagnosis task, a multi-agent synchronous diagnosis federation integrated different knowledge expression modes and inference mechanisms are presented, the functions of management agent, diagnosis agent and decision agent are analyzed, the organization and evolution of agents in the system are proposed, and the corresponding conflict resolution algorithm in given, Layered structure of abstract agent with public attributes is build. System architecture is realized based on MAS distributed layered blackboard. The real world application shows that the proposed control structure successfully solves the fault diagnose problem of the complex plant, and the special advantage in the distributed domain.

Comparing the Suitability of Autodock, Gold and Glide for the Docking and Predicting the Possible Targets of Ru(II-Based Complexes as Anticancer Agents

Directory of Open Access Journals (Sweden)

Adebayo A. Adeniyi

2013-03-01

Full Text Available In cancer chemotherapy, metal-based complexes have been recognized as the most promising means of inhibiting cancer growth due to the successful application of cis-platin and its derivatives above many of the existing organic anticancer agents. The limitations in their rational design can be traced to the complexity of the mechanism of their operations, lack of proper knowledge of their targets and lack of force fields in docking packages to appropriately define the metal centre of the organometallic complexes. In this paper, some of the promising anticancer complexes of Ru(II such as the rapta-based complexes formulated as [Ru(η6-p-cymeneL2(pta] and those with unusual ligands are considered. CatB and kinases which have been experimentally confirmed as possible targets of the complexes are also predicted by the three methods as one of the most targeted receptors while TopII and HDAC7 are predicted by two and one of the methods as best targets. The interesting features of the binding of the complexes show that some of the complexes preferentially target specific macromolecules than the others, which is an indication of their specificity and possibility of their therapeutic combination without severe side effects that may come from competition for the same target. Also, introduction of unusual ligands is found to significantly improve the activities of most of the complexes studied. Strong correlations are observed for the predicted binding sites and the orientation of the complexes within the binding site by the three methods of docking. However there are disparities in the ranking of the complexes by the three method of docking, especially that of Glide.

Solution structure of the luzopeptin-DNA complex

International Nuclear Information System (INIS)

Zhang, Xiaolu; Patel, D.J.

1991-01-01

The luzopeptin-d(C-A-T-G) complex (1 drug/duplex) has been generated in aqueous solution and its structure characterized by a combined application of two-dimensional NMR experiments and molecular dynamics calculations. Once equivalent of luzopeptin binds to the self-complementary tetranucleotide duplex with the 2-fold symmetry of the antitumor agent and the DNA oligomer retained on complex formation. The authors have assigned the exchangeable and nonexchangeable proton resonances of luzopeptin and the d(C-A-T-G) duplex in the complex and identified the intermolecular proton-proton NOEs that define the alignment of the antitumor agent at its binding site in duplex DNA. The analysis was greatly aided by a large number of intermolecular NOEs involving exchangeable protons on both the luzopeptin and the DNA in the complex. The formation of cis peptide bonds for luzopeptin in the complex results in an increased separation of the long sides of the rectangular cyclic depsipeptide backbone and reorients in the glycine amide proton so that it can form an intermolecular hydrogen bond with the 2-carbonyl of T3 in the complex. This observation explains, in part, the requirement for Watson-Crick A·T pairs to be sandwiched between the quinolines at the bisintercalation site in the luzopeptin-DNA complex. The NMR studies on the luzopeptin-d(C-A-T-G) complex unequivocally establish that antitumor agents can undergo conformational transitions on complex formation with DNA, and it is the conformation of the drug in the complex that should serve as the starting point for drug design studies. The above structural details on the solution structure of the luzopeptin-DNA complex also explain the sequence selectivity of luzopeptin for bisintercalation at d(C-A)·d(T-G) steps in the d(C-A-T-G) duplex in solution

Multi-agent systems: effective approach for cancer care information management.

Science.gov (United States)

Mohammadzadeh, Niloofar; Safdari, Reza; Rahimi, Azin

2013-01-01

Physicians, in order to study the causes of cancer, detect cancer earlier, prevent or determine the effectiveness of treatment, and specify the reasons for the treatment ineffectiveness, need to access accurate, comprehensive, and timely cancer data. The cancer care environment has become more complex because of the need for coordination and communication among health care professionals with different skills in a variety of roles and the existence of large amounts of data with various formats. The goals of health care systems in such a complex environment are correct health data management, providing appropriate information needs of users to enhance the integrity and quality of health care, timely access to accurate information and reducing medical errors. These roles in new systems with use of agents efficiently perform well. Because of the potential capability of agent systems to solve complex and dynamic health problems, health care system, in order to gain full advantage of E- health, steps must be taken to make use of this technology. Multi-agent systems have effective roles in health service quality improvement especially in telemedicine, emergency situations and management of chronic diseases such as cancer. In the design and implementation of agent based systems, planning items such as information confidentiality and privacy, architecture, communication standards, ethical and legal aspects, identification opportunities and barriers should be considered. It should be noted that usage of agent systems only with a technical view is associated with many problems such as lack of user acceptance. The aim of this commentary is to survey applications, opportunities and barriers of this new artificial intelligence tool for cancer care information as an approach to improve cancer care management.

Microwave Saturation of Complex EPR Spectra and Free Radicals of Burnt Skin Treated with Apitherapeutic Agent

Directory of Open Access Journals (Sweden)

Pawel Olczyk

2013-01-01

Full Text Available The effect of microwave power on the complex electron paramagnetic resonance spectra of the burn matrix after the therapy with propolis was examined. The spectra were measured with microwaves in the range of 2.2–79 mW. Three groups of free radicals were found in the damaged skin samples. Their spectral lines evolve differently with the microwave power. In order to detect these free radical groups, the lineshape of the spectra was numerically analysed. The spectra were a superposition of three component lines. The best fit was obtained for the deconvolution of the experimental spectra into one Gauss and two Lorentz lines. The microwave power changes also the lineshape of the spectra of thermally injured skin treated with the conventional agent—silver sulphadiazine. The spectral changes were different for propolis and for silver sulphadiazine. The number of individual groups of free radicals in the wound bed after implementation of these two substances is not equal. It may be explained by a higher activity of propolis than of silver sulphadiazine as therapeutic agents.

Synthesis of technetium-99m labeled clinafloxacin (99mTc-CNN) complex and biological evaluation as a potential Staphylococcus aureus infection imaging agent

International Nuclear Information System (INIS)

Syed Qaiser Shah; Muhammad Rafiullah Khan

2011-01-01

In the present study synthesis of the 99m Tc-CNN complex and its efficacy as a prospective Staphylococcus aureus (S. aureus) infection imaging agent was assessed. The 99m Tc-CNN complex was characterized in terms of stability in saline, serum, in vitro binding with S. aureus and in vivo percent absorption in male Wister rats (MWR) infected with live and heat killed S. aureus. Radiochemically the 99m Tc-CNN complex showed stable behavior in saline and serum at different intervals. At 30 min after reconstitution the complex showed maximum radiochemical purity (RCP) yield of 97.55 ± 0.22%. The RCP yield decreased to 90.50 ± 0.18% within 240 min. In serum, 18.15% unwanted side product was appeared within 16 h of the incubation. In vitro saturated binding with S. aureus was observed at different intervals with a 62.00% maximum at 90 min. Normal percent in vivo uptake was observed in MWR artificially infected with live S. aureus with a five times higher in the infected muscle as compared to the inflamed and normal muscles. No difference in the percent uptake of the complex in MWR infected with heat killed S. aureus in the infected, inflamed and normal muscles were observed. Based on the promising in vitro and in vivo radiochemical and biological characteristics, we recommend the 99m Tc-CNN complex for in vivo localization of the S. aureus infectious foci. (author)

Chemical genetics analysis of an aniline mustard anticancer agent reveals complex I of the electron transport chain as a target.

Science.gov (United States)

Fedeles, Bogdan I; Zhu, Angela Y; Young, Kellie S; Hillier, Shawn M; Proffitt, Kyle D; Essigmann, John M; Croy, Robert G

2011-09-30

The antitumor agent 11β (CAS 865070-37-7), consisting of a DNA-damaging aniline mustard linked to an androgen receptor (AR) ligand, is known to form covalent DNA adducts and to induce apoptosis potently in AR-positive prostate cancer cells in vitro; it also strongly prevents growth of LNCaP xenografts in mice. The present study describes the unexpectedly strong activity of 11β against the AR-negative HeLa cells, both in cell culture and tumor xenografts, and uncovers a new mechanism of action that likely explains this activity. Cellular fractionation experiments indicated that mitochondria are the major intracellular sink for 11β; flow cytometry studies showed that 11β exposure rapidly induced oxidative stress, mitochondria being an important source of reactive oxygen species (ROS). Additionally, 11β inhibited oxygen consumption both in intact HeLa cells and in isolated mitochondria. Specifically, 11β blocked uncoupled oxygen consumption when mitochondria were incubated with complex I substrates, but it had no effect on oxygen consumption driven by substrates acting downstream of complex I in the mitochondrial electron transport chain. Moreover, 11β enhanced ROS generation in isolated mitochondria, suggesting that complex I inhibition is responsible for ROS production. At the cellular level, the presence of antioxidants (N-acetylcysteine or vitamin E) significantly reduced the toxicity of 11β, implicating ROS production as an important contributor to cytotoxicity. Collectively, our findings establish complex I inhibition and ROS generation as a new mechanism of action for 11β, which supplements conventional DNA adduct formation to promote cancer cell death.

Using an agent-based model to analyze the dynamic communication network of the immune response

Directory of Open Access Journals (Sweden)

Doolittle John

2011-01-01

Full Text Available Abstract Background The immune system behaves like a complex, dynamic network with interacting elements including leukocytes, cytokines, and chemokines. While the immune system is broadly distributed, leukocytes must communicate effectively to respond to a pathological challenge. The Basic Immune Simulator 2010 contains agents representing leukocytes and tissue cells, signals representing cytokines, chemokines, and pathogens, and virtual spaces representing organ tissue, lymphoid tissue, and blood. Agents interact dynamically in the compartments in response to infection of the virtual tissue. Agent behavior is imposed by logical rules derived from the scientific literature. The model captured the agent-to-agent contact history, and from this the network topology and the interactions resulting in successful versus failed viral clearance were identified. This model served to integrate existing knowledge and allowed us to examine the immune response from a novel perspective directed at exploiting complex dynamics, ultimately for the design of therapeutic interventions. Results Analyzing the evolution of agent-agent interactions at incremental time points from identical initial conditions revealed novel features of immune communication associated with successful and failed outcomes. There were fewer contacts between agents for simulations ending in viral elimination (win versus persistent infection (loss, due to the removal of infected agents. However, early cellular interactions preceded successful clearance of infection. Specifically, more Dendritic Agent interactions with TCell and BCell Agents, and more BCell Agent interactions with TCell Agents early in the simulation were associated with the immune win outcome. The Dendritic Agents greatly influenced the outcome, confirming them as hub agents of the immune network. In addition, unexpectedly high frequencies of Dendritic Agent-self interactions occurred in the lymphoid compartment late in the

Agent Based Simulation of Group Emotions Evolution and Strategy Intervention in Extreme Events

Directory of Open Access Journals (Sweden)

Bo Li

2014-01-01

Full Text Available Agent based simulation method has become a prominent approach in computational modeling and analysis of public emergency management in social science research. The group emotions evolution, information diffusion, and collective behavior selection make extreme incidents studies a complex system problem, which requires new methods for incidents management and strategy evaluation. This paper studies the group emotion evolution and intervention strategy effectiveness using agent based simulation method. By employing a computational experimentation methodology, we construct the group emotion evolution as a complex system and test the effects of three strategies. In addition, the events-chain model is proposed to model the accumulation influence of the temporal successive events. Each strategy is examined through three simulation experiments, including two make-up scenarios and a real case study. We show how various strategies could impact the group emotion evolution in terms of the complex emergence and emotion accumulation influence in extreme events. This paper also provides an effective method of how to use agent-based simulation for the study of complex collective behavior evolution problem in extreme incidents, emergency, and security study domains.

A mathematical framework for agent based models of complex biological networks.

Science.gov (United States)

Hinkelmann, Franziska; Murrugarra, David; Jarrah, Abdul Salam; Laubenbacher, Reinhard

2011-07-01

Agent-based modeling and simulation is a useful method to study biological phenomena in a wide range of fields, from molecular biology to ecology. Since there is currently no agreed-upon standard way to specify such models, it is not always easy to use published models. Also, since model descriptions are not usually given in mathematical terms, it is difficult to bring mathematical analysis tools to bear, so that models are typically studied through simulation. In order to address this issue, Grimm et al. proposed a protocol for model specification, the so-called ODD protocol, which provides a standard way to describe models. This paper proposes an addition to the ODD protocol which allows the description of an agent-based model as a dynamical system, which provides access to computational and theoretical tools for its analysis. The mathematical framework is that of algebraic models, that is, time-discrete dynamical systems with algebraic structure. It is shown by way of several examples how this mathematical specification can help with model analysis. This mathematical framework can also accommodate other model types such as Boolean networks and the more general logical models, as well as Petri nets.

TmDOTA-tetraglycinate encapsulated liposomes as pH-sensitive LipoCEST agents.

Directory of Open Access Journals (Sweden)

Ana Christina L Opina

Full Text Available Lanthanide DOTA-tetraglycinate (LnDOTA-(gly₄⁻ complexes contain four magnetically equivalent amide protons that exchange with protons of bulk water. The rate of this base catalyzed exchange process has been measured using chemical exchange saturation transfer (CEST NMR techniques as a function of solution pH for various paramagnetic LnDOTA-(gly₄⁻ complexes to evaluate the effects of lanthanide ion size on this process. Complexes with Tb(III, Dy(III, Tm(III and Yb(III were chosen because these ions induce large hyperfine shifts in all ligand protons, including the exchanging amide protons. The magnitude of the amide proton CEST exchange signal differed for the four paramagnetic complexes in order, Yb>Tm>Tb>Dy. Although the Dy(III complex showed the largest hyperfine shift as expected, the combination of favorable chemical shift and amide proton CEST linewidth in the Tm(III complex was deemed most favorable for future in vivo applications where tissue magnetization effects can interfere. TmDOTA-(gly₄⁻ at various concentrations was encapsulated in the core interior of liposomes to yield lipoCEST particles for molecular imaging. The resulting nanoparticles showed less than 1% leakage of the agent from the interior over a range of temperatures and pH. The pH versus amide proton CEST curves differed for the free versus encapsulated agents over the acidic pH regions, consistent with a lower proton permeability across the liposomal bilayer for the encapsulated agent. Nevertheless, the resulting lipoCEST nanoparticles amplify the CEST sensitivity by a factor of ∼10⁴ compared to the free, un-encapsulated agent. Such pH sensitive nano-probes could prove useful for pH mapping of liposomes targeted to tumors.

Efficiency of Composite Binders with Antifreezing Agents

Science.gov (United States)

Ogurtsova, Y. N.; Zhernovsky, I. V.; Botsman, L. N.

2017-11-01

One of the non-heating methods of cold-weather concreting is using concretes hardening at negative temperatures. This method consists in using chemical additives which reduce the freezing temperature of the liquid phase and provide for concrete hardening at negative temperatures. The non-heating cold-weather concreting, due to antifreezing agents, allows saving heat and electric energy at the more flexible work performance technology. At selecting the antifreezing components, the possibility of concreting at temperatures up to minus 20 °C and combination with a plasticizer contained in the composite binder were taken into account. The optimal proportions of antifreezing and complex agents produced by MC-Bauchemie Russia for fine-grained concretes were determined. So, the introduction of antifreezing and complex agents allows obtaining a structure of composite characteristic for cement stone in the conditions of below zero temperatures at using different binders; the hydration of such composite proceeded naturally. Low-water-demand binders (LWDB) based composites are characterized by a higher density and homogeneity due to a high dispersity of a binder and its complicated surface providing for a lot of crystallization centers. LWDB contains small pores keeping water in a liquid form and promoting a more complete hydration process.

Corrosion in the presence of a complexing agent - application to the continuous determination of hydrofluoric acid in the atmosphere

International Nuclear Information System (INIS)

Chapron, J.

1966-10-01

After a presentation of the thermodynamics and kinetics involved during corrosion in the presence of a complexing agent, the first part of this report deals with the electrochemical properties of an aluminium electrode in the presence of fluoride solutions. Various physical and chemical parameters have been studied together with their influence on the aforementioned properties. From this first part are deduced the medium and the various parameters which lead to the maximum efficiency for the detection of fluorides by amperometry. The second part is an application of the results of the above work, which has made it possible to develop a cell having an original design. Its performances are described. They show that the cell has a greater sensitivity and a shorter response time than existing equipment. (author) [fr

FY1995 community support by mobile agents; 1995 nendo mobile agent ni yoru community keisei shien

Energy Technology Data Exchange (ETDEWEB)

NONE

1997-03-01

The purpose is to develop fundamental technologies for navigation systems and mobile computing systems in museums, theme parks and cities. Concretely, we implement software agents into the mobile computing environment which consists of PHS, mobile computers and mobile robots, and realize various functions to access regional information. We have studied on Communityware which supports human activities and communities by using mobile agents implemented into mobile computers and town robots. The mobile agents, which intelligently process information obtained in physical and virtual worlds, access regional information which is omnipresent in the environment. With respect to the approach using mobile computers, we have provided one hundred mobile computers in the international conference on multiagent systems 1996 and carried out the first experimentation of mobile computing in the world. The mobile computer has two functions: Community Viewer which displays interactions between members of communities and Social Matchmaker which supports to hold meetings by searching for people who have common interests. With respect to the approach using town robots, we have developed a robot system which can robustly behave in a complex outdoor environment by using vision agents embedded in the environment. The system aims at support of people in streets. (NEDO)

A real-time architecture for time-aware agents.

Science.gov (United States)

Prouskas, Konstantinos-Vassileios; Pitt, Jeremy V

2004-06-01

This paper describes the specification and implementation of a new three-layer time-aware agent architecture. This architecture is designed for applications and environments where societies of humans and agents play equally active roles, but interact and operate in completely different time frames. The architecture consists of three layers: the April real-time run-time (ART) layer, the time aware layer (TAL), and the application agents layer (AAL). The ART layer forms the underlying real-time agent platform. An original online, real-time, dynamic priority-based scheduling algorithm is described for scheduling the computation time of agent processes, and it is shown that the algorithm's O(n) complexity and scalable performance are sufficient for application in real-time domains. The TAL layer forms an abstraction layer through which human and agent interactions are temporally unified, that is, handled in a common way irrespective of their temporal representation and scale. A novel O(n2) interaction scheduling algorithm is described for predicting and guaranteeing interactions' initiation and completion times. The time-aware predicting component of a workflow management system is also presented as an instance of the AAL layer. The described time-aware architecture addresses two key challenges in enabling agents to be effectively configured and applied in environments where humans and agents play equally active roles. It provides flexibility and adaptability in its real-time mechanisms while placing them under direct agent control, and it temporally unifies human and agent interactions.

Contrasts agents in magnetic resonance imaging

International Nuclear Information System (INIS)

Bonnet, P.A.; Fernandez, J.P.; Milhavet, J.C.; Chapat, J.P.; Almes, C.; Bruel, J.M.; Rouanet, J.P.; Lamarque, J.L.

1984-01-01

Changing different parameters involved in imaging procedures, paramagnetic substances provide contrast enhancement in MRI. Contrast agents presently studied in animals and clinical trials, are either salts or complexes of mineral ions either nitroxide stable free radicals. Their development should extend the possibilities of tissular characterization and fonctional or metabolic evaluation of the MRI [fr

An agent-based hydroeconomic model to evaluate water policies in Jordan

Science.gov (United States)

Yoon, J.; Gorelick, S.

2014-12-01

Modern water systems can be characterized by a complex network of institutional and private actors that represent competing sectors and interests. Identifying solutions to enhance water security in such systems calls for analysis that can adequately account for this level of complexity and interaction. Our work focuses on the development of a hierarchical, multi-agent, hydroeconomic model that attempts to realistically represent complex interactions between hydrologic and multi-faceted human systems. The model is applied to Jordan, one of the most water-poor countries in the world. In recent years, the water crisis in Jordan has escalated due to an ongoing drought and influx of refugees from regional conflicts. We adopt a modular approach in which biophysical modules simulate natural and engineering phenomena, and human modules represent behavior at multiple scales of decision making. The human modules employ agent-based modeling, in which agents act as autonomous decision makers at the transboundary, state, organizational, and user levels. A systematic nomenclature and conceptual framework is used to characterize model agents and modules. Concepts from the Unified Modeling Language (UML) are adopted to promote clear conceptualization of model classes and process sequencing, establishing a foundation for full deployment of the integrated model in a scalable object-oriented programming environment. Although the framework is applied to the Jordanian water context, it is generalizable to other regional human-natural freshwater supply systems.

A Statistical Physics Characterization of the Complex Systems Dynamics: Quantifying Complexity from Spatio-Temporal Interactions

Science.gov (United States)

Koorehdavoudi, Hana; Bogdan, Paul

2016-06-01

Biological systems are frequently categorized as complex systems due to their capabilities of generating spatio-temporal structures from apparent random decisions. In spite of research on analyzing biological systems, we lack a quantifiable framework for measuring their complexity. To fill this gap, in this paper, we develop a new paradigm to study a collective group of N agents moving and interacting in a three-dimensional space. Our paradigm helps to identify the spatio-temporal states of the motion of the group and their associated transition probabilities. This framework enables the estimation of the free energy landscape corresponding to the identified states. Based on the energy landscape, we quantify missing information, emergence, self-organization and complexity for a collective motion. We show that the collective motion of the group of agents evolves to reach the most probable state with relatively lowest energy level and lowest missing information compared to other possible states. Our analysis demonstrates that the natural group of animals exhibit a higher degree of emergence, self-organization and complexity over time. Consequently, this algorithm can be integrated into new frameworks to engineer collective motions to achieve certain degrees of emergence, self-organization and complexity.

Development of organic MRI contrast agents

International Nuclear Information System (INIS)

Hayashi, Hiroyuki; Sato, Yuichiro; Karasawa, Satoru; Koga, Noboru

2008-01-01

Described are trends of the development in the title since those agents with target properties are awaited for specific organ and regional MRI. The contrast agents alter the relaxation time of water proton to yield the enhanced contrast between organs and tissues with different water volumes. Nowadays Gd-complexes and nano-particle of superparamagnetic iron oxide (Fe(III)) are widely used for enhancing in clinic. Among organic compounds with paramagnetic spin, those possessing nitroxide radical like TEMPO- and PROXYL-radicals have been subject to development by their derivatization. High spin molecules conceivably affect the relaxivity, which, however, is found smaller per spin of synthesized triplet complexes than doublet ones. This has lead to basic approach for molecules restricting water movement due to their hydrogen bond like DNA as a model, for introducing many radicals in high molecular weight compounds, and their polymer, as one of which authors have developed a derivative of hyperbranched polymer (HPS)-TEMPO having the similar relaxivity to gadolinium-diethylenetiamine pentaacetid acid (Gd-DTPA) (R.T.)

Unicorn: Continual Learning with a Universal, Off-policy Agent

OpenAIRE

Mankowitz, Daniel J.; Žídek, Augustin; Barreto, André; Horgan, Dan; Hessel, Matteo; Quan, John; Oh, Junhyuk; van Hasselt, Hado; Silver, David; Schaul, Tom

2018-01-01

Some real-world domains are best characterized as a single task, but for others this perspective is limiting. Instead, some tasks continually grow in complexity, in tandem with the agent's competence. In continual learning, also referred to as lifelong learning, there are no explicit task boundaries or curricula. As learning agents have become more powerful, continual learning remains one of the frontiers that has resisted quick progress. To test continual learning capabilities we consider a ...

Towards a complex systems approach in sports injury research: simulating running-related injury development with agent-based modelling.

Science.gov (United States)

Hulme, Adam; Thompson, Jason; Nielsen, Rasmus Oestergaard; Read, Gemma J M; Salmon, Paul M

2018-06-18

There have been recent calls for the application of the complex systems approach in sports injury research. However, beyond theoretical description and static models of complexity, little progress has been made towards formalising this approach in way that is practical to sports injury scientists and clinicians. Therefore, our objective was to use a computational modelling method and develop a dynamic simulation in sports injury research. Agent-based modelling (ABM) was used to model the occurrence of sports injury in a synthetic athlete population. The ABM was developed based on sports injury causal frameworks and was applied in the context of distance running-related injury (RRI). Using the acute:chronic workload ratio (ACWR), we simulated the dynamic relationship between changes in weekly running distance and RRI through the manipulation of various 'athlete management tools'. The findings confirmed that building weekly running distances over time, even within the reported ACWR 'sweet spot', will eventually result in RRI as athletes reach and surpass their individual physical workload limits. Introducing training-related error into the simulation and the modelling of a 'hard ceiling' dynamic resulted in a higher RRI incidence proportion across the population at higher absolute workloads. The presented simulation offers a practical starting point to further apply more sophisticated computational models that can account for the complex nature of sports injury aetiology. Alongside traditional forms of scientific inquiry, the use of ABM and other simulation-based techniques could be considered as a complementary and alternative methodological approach in sports injury research. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2018. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

Network flow of mobile agents enhances the evolution of cooperation

Science.gov (United States)

Ichinose, G.; Satotani, Y.; Nagatani, T.

2018-01-01

We study the effect of contingent movement on the persistence of cooperation on complex networks with empty nodes. Each agent plays the Prisoner's Dilemma game with its neighbors and then it either updates the strategy depending on the payoff difference with neighbors or it moves to another empty node if not satisfied with its own payoff. If no neighboring node is empty, each agent stays at the same site. By extensive evolutionary simulations, we show that the medium density of agents enhances cooperation where the network flow of mobile agents is also medium. Moreover, if the movements of agents are more frequent than the strategy updating, cooperation is further promoted. In scale-free networks, the optimal density for cooperation is lower than other networks because agents get stuck at hubs. Our study suggests that keeping a smooth network flow is significant for the persistence of cooperation in ever-changing societies.

Intelligent agents for e-commerce applications

Science.gov (United States)

Vuppala, Krishna

1999-12-01

This thesis focuses on development of intelligent agent solutions for e-commerce applications. E-Commerce has several complexities like: lack of information about the players, learning the nature of one's business partners/competitors, finding the right business partner to do business with, using the right strategy to get best profit out of the negotiations etc. The agent models developed can be used in any agent solution for e-commerce. Concepts and techniques from Game Theory and Artificial Intelligence are used. The developed models have several advantages over the existing ones as: the models assume the non-availability of information about other players in the market, the models of players get updated over the time as and when new information comes about the players, the negotiation model incorporates the patience levels of the players and expectations from other players in the market. Power industry has been chosen as the application area for the demonstration of the capabilities and usage of the developed agent models. Two e-commerce scenarios where sellers and buyers can go through the power exchanges to bid in auctions, or make bilateral deals outside of the exchange are addressed. In the first scenario agent helps market participants in coordinating strategies with other participants, bidding in auctions by analyzing and understanding the behavior of other participants. In the second scenario, called "Power Traders Assistant" agent helps power trader, who buys and sells power through bilateral negotiations, in negotiating deals with his customers.

Phenolic aminocarboxylic acids - new chelating agents for modifying gallium-67 biodistribution

Energy Technology Data Exchange (ETDEWEB)

Hunt, F.C.; Maddalena, D.J. (Australian Atomic Energy Commission Research Establishment, Lucas Heights)

The chelating agents EDDHA and HBED were synthesised with carboxyl or sulphonyl groups in the phenolic ring to favour urinary excretion on complexing with gallium. Carboxyl EDDMA was administered to tumor-bearing rats, and its concentration in the tumours and other tissues determined by scintigraphic imaging. The chelating agents increase tumour to blood ratios by chelating gallium in vivo.

Modeling Dispersion of Chemical-Biological Agents in Three Dimensional Living Space

International Nuclear Information System (INIS)

William S. Winters

2002-01-01

This report documents a series of calculations designed to demonstrate Sandia's capability in modeling the dispersal of chemical and biological agents in complex three-dimensional spaces. The transport of particles representing biological agents is modeled in a single room and in several connected rooms. The influence of particle size, particle weight and injection method are studied

Modeling of retention of some fission products and actinides by ion-exchange chromatography with a complexing agent. Application to the determination of selectivity coefficients

International Nuclear Information System (INIS)

Gurdale-Tack, K.; Aubert, M.; Chartier, F.

2000-01-01

For an accurate determination of the isotopic and elemental composition of americium (Am), curium (Cm), neodymium (Nd) and cesium (Cs) in spent nuclear fuels, performed by Thermal Ionization Mass Spectrometry (TIMS) and Inductively Coupled Plasma Mass Spectrometry (ICP-MS), it is necessary to separate these elements before analysis. This separation is mandatory because of isobaric interferences between americium and curium, neodymium and samarium (Sm) and between cesium and barium (Ba). This is the reason why Ba and Sm are analyzed with the other four elements. Separation is carried out by cation-exchange chromatography on a silica-based stationary phase in the presence of a complexing eluent. The complexing agent is 2-hydroxy-2-methyl butanoic acid (HMB), a monoprotic acid (HL) with a pK a of 3.6. Cations (M n+ ) interact with it to form ML y (n-y)+ complexes. Optimization of chromatographic separation conditions requires monitoring of the pH and eluent composition. The influence of each parameter on metal ion retention and on selectivity was investigated. The first studies on standard solutions with Sm(III), Nd(III), Cs(I) and Ba(II) showed that four conditions allow efficient separation. However, only one allows good separation with a real solution of spent nuclear fuels. This condition is a chelating agent concentration of 0.1 mol.l -1 and a pH of 4.2. With the other conditions, co-elution is observed for Cs(I) and Am(III). The overall results were used to study the retention mechanisms. The aim of this modeling is a closer knowledge of the form in which (M n+ and/or ML y (n-y)+ ...) each cationic element is extracted into the stationary phase. In fact, while cations can exist in the eluent in various forms depending on the analytical conditions, their forms may be different in the stationary phase. (authors)

Synthesis and characterization of dihexyldithiocarbamate as a chelating agent in extraction of gold(III)

Energy Technology Data Exchange (ETDEWEB)

Fatimah, Soja Siti, E-mail: soja-sf@upi.edu [Departemen Pendidikan Kimia, Universitas Pendidikan Indonesia, Jl. Dr. Setiabudhi No. 229, Bandung 40154 (Indonesia); Department of Chemistry, Faculty of Mathematics and Natural Sciences, Padjadjaran University, Jl. Raya Bandung-Sumedang, Km. 21, Jatinangor (Indonesia); Bahti, Husein H.; Hastiawan, Iwan [Department of Chemistry, Faculty of Mathematics and Natural Sciences, Padjadjaran University, Jl. Raya Bandung-Sumedang, Km. 21, Jatinangor (Indonesia); Permanasari, Anna [Departemen Pendidikan Kimia, Universitas Pendidikan Indonesia, Jl. Dr. Setiabudhi No. 229, Bandung 40154 (Indonesia)

2016-02-08

The use of dialkyldithiocarbamates as chelating agents of transition metals have been developing for decades. Many chelating agents have been synthesized and used in the extraction of the metals. Studies on particular aspects of extraction of the metals, such as the effect of increasing hydrophobicity of chelating agents on the effectiveness of the extraction, have been done. However, despite the many studies on the synthesis and applications of this type of chelating agents, interests in the aspect of molecular structure of the synthesized ligands and of their complexes, have been limited. This study aimed at synthesizing and characterizing dihexylthiocarbamate, and using the ligand for the extraction of gold III). Characterization of the ligand and of its metal complex were done by using elemental analysis, DTG, and spectroscopic methods to include NMR, ({sup 1}H, and {sup 13}C), FTIR, and MS-ESI. Data on the synthesis, characterization, and the application of the ligand as a chelating agent are presented.

Synthesis and characterization of dihexyldithiocarbamate as a chelating agent in extraction of gold(III)

Science.gov (United States)

Fatimah, Soja Siti; Bahti, Husein H.; Hastiawan, Iwan; Permanasari, Anna

2016-02-01

The use of dialkyldithiocarbamates as chelating agents of transition metals have been developing for decades. Many chelating agents have been synthesized and used in the extraction of the metals. Studies on particular aspects of extraction of the metals, such as the effect of increasing hydrophobicity of chelating agents on the effectiveness of the extraction, have been done. However, despite the many studies on the synthesis and applications of this type of chelating agents, interests in the aspect of molecular structure of the synthesized ligands and of their complexes, have been limited. This study aimed at synthesizing and characterizing dihexylthiocarbamate, and using the ligand for the extraction of gold III). Characterization of the ligand and of its metal complex were done by using elemental analysis, DTG, and spectroscopic methods to include NMR, (1H, and 13C), FTIR, and MS-ESI. Data on the synthesis, characterization, and the application of the ligand as a chelating agent are presented.

Study of occupational risk agents and its probable hazards to human health; Estudo dos agentes de risco ocupacional e seus provaveis agravos na saude humana

Energy Technology Data Exchange (ETDEWEB)

Carneiro, Janete Cristina G. Gaburo; Alves, Alice dos Santos; Sanches, Matias P., E-mail: janetegc@ipen.br, E-mail: alicesante@hotmail.com, E-mail: msanches@ipen.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

2013-07-01

Currently the workplaces become increasingly complex and a strategy evaluation and the control of occupational risks agents is needed. Workers may be exposed to environmental agents (chemical, physical and biological) and other unsuitable conditions by performing tasks that involve these agents directly. The main objective of this study is to approach conceptual aspects of risk conditions, physical in nature, with emphasis on ionizing radiation and its interaction with other agents in occupational and environmental situations. To meet this goal, it is performed a literature review and a summary of the main occupational agents known or suspected to cause any adverse health effects in humans. According to the available literature the reported studies on the effects of combined exposures to radiation and others agents are recognized and, as far as possible, should be taken into account in evaluating of the potential radiation risks at low levels of exposure. (author)

Evolution of natural agents: preservation, advance, and emergence of functional information.

Science.gov (United States)

Sharov, Alexei A

2016-04-01

Biological evolution is often viewed narrowly as a change of morphology or allele frequency in a sequence of generations. Here I pursue an alternative informational concept of evolution, as preservation, advance, and emergence of functional information in natural agents. Functional information is a network of signs (e.g., memory, transient messengers, and external signs) that are used by agents to preserve and regulate their functions. Functional information is preserved in evolution via complex interplay of copying and construction processes: the digital components are copied, whereas interpreting subagents together with scaffolds, tools, and resources, are constructed. Some of these processes are simple and invariant, whereas others are complex and contextual. Advance of functional information includes improvement and modification of already existing functions. Although the genome information may change passively and randomly, the interpretation is active and guided by the logic of agent behavior and embryonic development. Emergence of new functions is based on the reinterpretation of already existing information, when old tools, resources, and control algorithms are adopted for novel functions. Evolution of functional information progressed from protosemiosis, where signs correspond directly to actions, to eusemiosis, where agents associate signs with objects. Language is the most advanced form of eusemiosis, where the knowledge of objects and models is communicated between agents.

Bone-seeking /sup 99m/Tc complex

International Nuclear Information System (INIS)

Subramanian, G.; McAfee, J.G.

1977-01-01

A bone-seeking, technetium-99m-tin-phosphonate complex effective as a skeletal-imaging agent has been found particularly useful for diagnostic purposes. Skeletal tissue concentrations or technetium-99m obtained with the complex compare favorably to other bone-seeking radionuclides

Highly stabilized gadolinium chelates functionalized on metal nanoparticles as magnetic resonance imaging contrast agent

Science.gov (United States)

Siddiqui, Talha S.

Magnetic resonance imaging (MRI) is a non-invasive method for imaging and diagnosing tissue damage, organ function and the vascular system. Magnevist(TM) a complex of diethylenetriaminepentaacetic acid (DTPA) and Gd3+ is a clinically approved contrast agent for MRI. A derivative of DTPA was formed by the addition of two cysteine groups (DTPA-L-Cys) through amide linkage. The Gd complex of this ligand bonds with the silver surfaces through the cysteine thiols. GdDTPA-L-Cys was bound to ˜10nm diameter Ag nanoparticles for use as a multifunctional MRI contrast agent. The ligand and complex were characterized by 1H and 13C NMR, ESI-MS and IR spectroscopy. The silver construct was characterized by TEM, TGA and UV-Vis absorption spectra. The per metal complex r1 relaxivity of GdDTPA-L-Cys{Ag} greater than that of Magnavist(TM) with the same molarity for both compounds. The synthesis of a DTPA derivative is described that allows it to bind to silver or gold nanoparticles through a single thiol linkage (DTPASH). The resulting Gd complex, GdDTPASH, was bound to Ag nanoparticles to create a single monolayer on the surface. The construct was further stabilized in buffered solution with the addition of a thiolated PEG chain. The highly stabilized nanoparticle construct delivers a high payload of Gd compelex and is an effective T1 brightening agent. The production of this type of construct opens the way for engineered multimodal MRI contrast agents.

Evolvable Work-Practice Interfaces Between Humans and Agents, Phase I

Data.gov (United States)

National Aeronautics and Space Administration — NASA science researchers and payload specialists will be supported in their tasks by increasingly complex computational components. Whether these are agents...

Nanoparticles in magnetic resonance imaging: from simple to dual contrast agents

Directory of Open Access Journals (Sweden)

Estelrich J

2015-03-01

Full Text Available Joan Estelrich,1,2 María Jesús Sánchez-Martín,1 Maria Antònia Busquets1,2 1Departament de Fisicoquímica, Facultat de Farmàcia, Universitat de Barcelona, Barcelona, Catalonia, Spain; 2Institut de Nanociència I Nanotecnologia (IN2UB, Barcelona, Catalonia, SpainAbstract: Magnetic resonance imaging (MRI has become one of the most widely used and powerful tools for noninvasive clinical diagnosis owing to its high degree of soft tissue contrast, spatial resolution, and depth of penetration. MRI signal intensity is related to the relaxation times (T1, spin–lattice relaxation and T2, spin–spin relaxation of in vivo water protons. To increase contrast, various inorganic nanoparticles and complexes (the so-called contrast agents are administered prior to the scanning. Shortening T1 and T2 increases the corresponding relaxation rates, 1/T1 and 1/T2, producing hyperintense and hypointense signals respectively in shorter times. Moreover, the signal-to-noise ratio can be improved with the acquisition of a large number of measurements. The contrast agents used are generally based on either iron oxide nanoparticles or ferrites, providing negative contrast in T2-weighted images; or complexes of lanthanide metals (mostly containing gadolinium ions, providing positive contrast in T1-weighted images. Recently, lanthanide complexes have been immobilized in nanostructured materials in order to develop a new class of contrast agents with functions including blood-pool and organ (or tumor targeting. Meanwhile, to overcome the limitations of individual imaging modalities, multimodal imaging techniques have been developed. An important challenge is to design all-in-one contrast agents that can be detected by multimodal techniques. Magnetoliposomes are efficient multimodal contrast agents. They can simultaneously bear both kinds of contrast and can, furthermore, incorporate targeting ligands and chains of polyethylene glycol to enhance the accumulation of

An Intelligent Agent based Architecture for Visual Data Mining

OpenAIRE

Hamdi Ellouzi; Hela Ltifi; Mounir Ben Ayed

2016-01-01

the aim of this paper is to present an intelligent architecture of Decision Support System (DSS) based on visual data mining. This architecture applies the multi-agent technology to facilitate the design and development of DSS in complex and dynamic environment. Multi-Agent Systems add a high level of abstraction. To validate the proposed architecture, it is implemented to develop a distributed visual data mining based DSS to predict nosocomial infectionsoccurrence in intensive care units. Th...

Behavior acquisition in artificial agents

OpenAIRE

Thurau, Christian

2006-01-01

Computational skill acquisition in robots and simulated agents has been a topic of increasing popularity throughout the last years. Despite impressive progress, autonomous behavior at a level of animals and humans are not yet replicated by machines. Especially when a complex environment demands versatile, goal-oriented behavior, current artificial systems show shortcomings. Consider for instance modern 3D computer games. Despite their key role for more emersive game experience, surprisingly l...

An intelligent agent for optimal river-reservoir system management

Science.gov (United States)

Rieker, Jeffrey D.; Labadie, John W.

2012-09-01

A generalized software package is presented for developing an intelligent agent for stochastic optimization of complex river-reservoir system management and operations. Reinforcement learning is an approach to artificial intelligence for developing a decision-making agent that learns the best operational policies without the need for explicit probabilistic models of hydrologic system behavior. The agent learns these strategies experientially in a Markov decision process through observational interaction with the environment and simulation of the river-reservoir system using well-calibrated models. The graphical user interface for the reinforcement learning process controller includes numerous learning method options and dynamic displays for visualizing the adaptive behavior of the agent. As a case study, the generalized reinforcement learning software is applied to developing an intelligent agent for optimal management of water stored in the Truckee river-reservoir system of California and Nevada for the purpose of streamflow augmentation for water quality enhancement. The intelligent agent successfully learns long-term reservoir operational policies that specifically focus on mitigating water temperature extremes during persistent drought periods that jeopardize the survival of threatened and endangered fish species.

Brownian agents and active particles collective dynamics in the natural and social sciences

CERN Document Server

Schweitzer, Frank

2007-01-01

""This book lays out a vision for a coherent framework for understanding complex systems"" (from the foreword by J. Doyne Farmer). By developing the genuine idea of Brownian agents, the author combines concepts from informatics, such as multiagent systems, with approaches of statistical many-particle physics. This way, an efficient method for computer simulations of complex systems is developed which is also accessible to analytical investigations and quantitative predictions. The book demonstrates that Brownian agent models can be successfully applied in many different contexts, ranging from

Modelling of robotic work cells using agent based-approach

Science.gov (United States)

Sękala, A.; Banaś, W.; Gwiazda, A.; Monica, Z.; Kost, G.; Hryniewicz, P.

2016-08-01

In the case of modern manufacturing systems the requirements, both according the scope and according characteristics of technical procedures are dynamically changing. This results in production system organization inability to keep up with changes in a market demand. Accordingly, there is a need for new design methods, characterized, on the one hand with a high efficiency and on the other with the adequate level of the generated organizational solutions. One of the tools that could be used for this purpose is the concept of agent systems. These systems are the tools of artificial intelligence. They allow assigning to agents the proper domains of procedures and knowledge so that they represent in a self-organizing system of an agent environment, components of a real system. The agent-based system for modelling robotic work cell should be designed taking into consideration many limitations considered with the characteristic of this production unit. It is possible to distinguish some grouped of structural components that constitute such a system. This confirms the structural complexity of a work cell as a specific production system. So it is necessary to develop agents depicting various aspects of the work cell structure. The main groups of agents that are used to model a robotic work cell should at least include next pattern representatives: machine tool agents, auxiliary equipment agents, robots agents, transport equipment agents, organizational agents as well as data and knowledge bases agents. In this way it is possible to create the holarchy of the agent-based system.

Physical properties of the Creutzfeldt-Jakob disease agent

Energy Technology Data Exchange (ETDEWEB)

Sklaviadis, T.K.; Manuelidis, L.; Manuelidis, E.E.

1989-03-01

In this report, the authors present the first physical characterization of the Creutzfeld-Jakob disease agent. Preparations with high yields of infectivity (assayed infectious units) were obtained by a novel, gentle procedure in which initially sedimenting Gp34 (prion protein) was disaggregated by a variety of criteria with no subsequent loss of infectivity. Studies with this preparation indicate that most of the Creutzfeldt-Jakob disease agent has both a viruslike size and density. In velocity sedimentation and isopycnic sucrose gradients, infectivity comigrated with nucleic acid-protein complexes of appreciable size.

Physical properties of the Creutzfeldt-Jakob disease agent

International Nuclear Information System (INIS)

Sklaviadis, T.K.; Manuelidis, L.; Manuelidis, E.E.

1989-01-01

In this report, the authors present the first physical characterization of the Creutzfeld-Jakob disease agent. Preparations with high yields of infectivity (assayed infectious units) were obtained by a novel, gentle procedure in which initially sedimenting Gp34 (prion protein) was disaggregated by a variety of criteria with no subsequent loss of infectivity. Studies with this preparation indicate that most of the Creutzfeldt-Jakob disease agent has both a viruslike size and density. In velocity sedimentation and isopycnic sucrose gradients, infectivity comigrated with nucleic acid-protein complexes of appreciable size

Phenolic aminocarboxylic acids - new chelating agents for modifying gallium-67 biodistribution

International Nuclear Information System (INIS)

Hunt, F.C.; Maddalena, D.J.

1982-01-01

The chelating agents EDDHA and HBED were synthesised with carboxyl or sulphonyl groups in the phenolic ring to favour urinary excretion on complexing with gallium. Carboxyl EDDMA was administered to tumor-bearing rats, and its concentration in the tumours and other tissues determined by scintigraphic imaging. The chelating agents increase tumour to blood ratios by chelating gallium in vivo. (U.K.)

Improving Agent Bidding in Power Stock Markets through a Data Mining Enhanced Agent Platform

Science.gov (United States)

Chrysopoulos, Anthony C.; Symeonidis, Andreas L.; Mitkas, Pericles A.

Like in any other auctioning environment, entities participating in Power Stock Markets have to compete against other in order to maximize own revenue. Towards the satisfaction of their goal, these entities (agents - human or software ones) may adopt different types of strategies - from na?ve to extremely complex ones - in order to identify the most profitable goods compilation, the appropriate price to buy or sell etc, always under time pressure and auction environment constraints. Decisions become even more difficult to make in case one takes the vast volumes of historical data available into account: goods’ prices, market fluctuations, bidding habits and buying opportunities. Within the context of this paper we present Cassandra, a multi-agent platform that exploits data mining, in order to extract efficient models for predicting Power Settlement prices and Power Load values in typical Day-ahead Power markets. The functionality of Cassandra is discussed, while focus is given on the bidding mechanism of Cassandra’s agents, and the way data mining analysis is performed in order to generate the optimal forecasting models. Cassandra has been tested in a real-world scenario, with data derived from the Greek Energy Stock market.

Smart Contrast Agents for Magnetic Resonance Imaging.

Science.gov (United States)

Bonnet, Célia S; Tóth, Éva

2016-01-01

By visualizing bioactive molecules or biological parameters in vivo, molecular imaging is searching for information at the molecular level in living organisms. In addition to contributing to earlier and more personalized diagnosis in medicine, it also helps understand and rationalize the molecular factors underlying physiological and pathological processes. In magnetic resonance imaging (MRI), complexes of paramagnetic metal ions, mostly lanthanides, are commonly used to enhance the intrinsic image contrast. They rely either on the relaxation effect of these metal chelates (T(1) agents), or on the phenomenon of paramagnetic chemical exchange saturation transfer (PARACEST agents). In both cases, responsive molecular magnetic resonance imaging probes can be designed to report on various biomarkers of biological interest. In this context, we review recent work in the literature and from our group on responsive T(1) and PARACEST MRI agents for the detection of biogenic metal ions (such as calcium or zinc), enzymatic activities, or neurotransmitter release. These examples illustrate the general strategies that can be applied to create molecular imaging agents with an MRI detectable response to biologically relevant parameters.

Near-infrared-emitting heteroleptic cationic iridium complexes derived from 2,3-diphenylbenzo[g]quinoxaline as in vitro theranostic photodynamic therapy agents

Energy Technology Data Exchange (ETDEWEB)

Wang, Li; Yin, Huimin; Cui, Peng; Hetu, Marc; Wang, Chengzhe; Monro, Susan; Schaller, Richard D.; Cameron, Colin G.; Liu, Bingqing; Kilina, Svetlana; McFarland, Sherri A.; Sun, Wenfang

2017-05-19

3. The quqo coligand produced the most potent complex 5 for in vitro PDT, both in terms of photocytotoxicity and PI. All Ir(III) complexes exhibited very bright NIR phosphorescence in melanoma cells. The wide range of cytotoxicity and photocytotoxicity effects within a relatively small class of complexes highlights the importance of the identity of the coligand in the biological activity of the π-expansive biscyclometalated Ir(III) complexes, and their bright NIR emission in live cells demonstrates their potential as theranostic PDT agents.

An Agent-Based Modeling Framework and Application for the Generic Nuclear Fuel Cycle

Science.gov (United States)

Gidden, Matthew J.

Key components of a novel methodology and implementation of an agent-based, dynamic nuclear fuel cycle simulator, Cyclus , are presented. The nuclear fuel cycle is a complex, physics-dependent supply chain. To date, existing dynamic simulators have not treated constrained fuel supply, time-dependent, isotopic-quality based demand, or fuel fungibility particularly well. Utilizing an agent-based methodology that incorporates sophisticated graph theory and operations research techniques can overcome these deficiencies. This work describes a simulation kernel and agents that interact with it, highlighting the Dynamic Resource Exchange (DRE), the supply-demand framework at the heart of the kernel. The key agent-DRE interaction mechanisms are described, which enable complex entity interaction through the use of physics and socio-economic models. The translation of an exchange instance to a variant of the Multicommodity Transportation Problem, which can be solved feasibly or optimally, follows. An extensive investigation of solution performance and fidelity is then presented. Finally, recommendations for future users of Cyclus and the DRE are provided.

Contrast agents in magnetic resonance imaging

International Nuclear Information System (INIS)

Karadjian, V.

1987-01-01

The origine of nuclear magnetic resonance signal is reminded and different ways for contrast enhancement in magnetic resonance imaging are presented, especially, modifications of tissus relaxation times. Investigations have focused on development of agents incorporating either paramagnetic ions or stable free radicals. Pharmacological and toxicological aspects are developed. The diagnostic potential of these substances is illustrated by the example of gadolinium complexes [fr

Structure and catalytic properties of metal β-diketonate complexes with oxygen-containing compounds

International Nuclear Information System (INIS)

Nizel'skij, Yu.N.; Ishchenko, S.S.; Lipatova, T.Eh.

1985-01-01

The results of researches published in recent 15-20 years of complexes of metal β-diketonates (including Cr 3+ , VO 2+ , MoOΛ2 2+ , Co 3+ , Mn 3+ , Ni 2+ , Fe 3+ ) with oxygen-containing compounds (alcohols, glycols, phenols, hydroperoxides, aldehydes, esters, etc.) playing an important role in catalytic processes of oxidation, addition, polymerization and copolymerization are reviewed. Data on the nature of chemical bond of oxygen-containing reacting agents with metal β-diketonates, on structure of metal β-diketonate complexes with oxygen-containing reacting agents and thermodynamics of complexing as well as on activation of reacting agents in complexes and catalytic properties of metal β-diketonates are discussed. Stored materials make it possible to exercise directed control of metal β-diketonate activity

A multi-agent system for coordinating international shipping

Energy Technology Data Exchange (ETDEWEB)

Goldsmith, S.Y.; Phillips, L.R.; Spires, S.V.

1998-05-01

Moving commercial cargo across the US-Mexico border is currently a complex, paper-based, error-prone process that incurs expensive inspections and delays at several ports of entry in the Southwestern US. Improved information handling will dramatically reduce border dwell time, variation in delivery time, and inventories, and will give better control of the shipment process. The Border Trade Facilitation System (BTFS) is an agent-based collaborative work environment that assists geographically distributed commercial and government users with transshipment of goods across the US-Mexico border. Software agents mediate the creation, validation and secure sharing of shipment information and regulatory documentation over the Internet, using the World Wide Web to interface with human actors. Agents are organized into Agencies. Each agency represents a commercial or government agency. Agents perform four specific functions on behalf of their user organizations: (1) agents with domain knowledge elicit commercial and regulatory information from human specialists through forms presented via web browsers; (2) agents mediate information from forms with diverse otologies, copying invariant data from one form to another thereby eliminating the need for duplicate data entry; (3) cohorts of distributed agents coordinate the work flow among the various information providers and they monitor overall progress of the documentation and the location of the shipment to ensure that all regulatory requirements are met prior to arrival at the border; (4) agents provide status information to human actors and attempt to influence them when problems are predicted.

Perspectives in the development of hybrid bifunctional antitumour agents.

Science.gov (United States)

Musso, Loana; Dallavalle, Sabrina; Zunino, Franco

2015-08-15

In spite of the development of a large number of novel target-specific antitumour agents, the single-agent therapy is in general not able to provide an effective durable control of the malignant process. The limited efficacy of the available agents (both conventional cytotoxic and novel target-specific) reflects not only the expression of defence mechanisms, but also the complexity of tumour cell alterations and the redundancy of survival pathways, thus resulting in tumour cell ability to survive under stress conditions. A well-established strategy to improve the efficacy of antitumour therapy is the rational design of drug combinations aimed at achieving synergistic effects and overcoming drug resistance. An alternative strategy could be the use of agents designed to inhibit simultaneously multiple cellular targets relevant to tumour growth/survival. Among these novel agents are hybrid bifunctional drugs, i.e. compounds resulting by conjugation of different drugs or containing the pharmocophores of different drugs. This strategy has been pursued using various conventional or target-specific agents (with DNA damaging agents and histone deacetylase inhibitors as the most exploited compounds). A critical overview of the most representative compounds is provided with emphasis on the HDAC inhibitor-based hybrid agents. In spite of some promising results, the actual pharmacological advantages of the hybrid agents remain to be defined. This commentary summarizes the recent advances in this field and highlights the pharmacological basis for a rational design of hybrid bifunctional agents. Copyright © 2015. Published by Elsevier Inc.

In vivo characterization of a smart MRI agent that displays an inverse response to calcium concentration.

Science.gov (United States)

Mamedov, Ilgar; Canals, Santiago; Henig, Jörg; Beyerlein, Michael; Murayama, Yusuke; Mayer, Hermann A; Logothetis, Nikos K; Angelovski, Goran

2010-12-15

Contrast agents for magnetic resonance imaging (MRI) that exhibit sensitivity toward specific ions or molecules represent a challenging but attractive direction of research. Here a Gd(3+) complex linked to an aminobis(methylenephosphonate) group for chelating Ca(2+) was synthesized and investigated. The longitudinal relaxivity (r(1)) of this complex decreases during the relaxometric titration with Ca(2+) from 5.76 to 3.57 mM(-1) s(-1) upon saturation. The r(1) is modulated by changes in the hydration number, which was confirmed by determination of the luminescence emission lifetimes of the analogous Eu(3+) complex. The initial in vivo characterization of this responsive contrast agent was performed by means of electrophysiology and MRI experiments. The investigated complex is fully biocompatible, having no observable effect on neuronal function after administration into the brain ventricles or parenchyma. Distribution studies demonstrated that the diffusivity of this agent is significantly lower compared with that of gadolinium-diethylenetriaminepentaacetic acid (Gd-DTPA).

Selective separation of yttrium by CA-100 in the presence of a complexing agent

International Nuclear Information System (INIS)

Sun Xiaobo; Wang Yige; Li Deqian

2006-01-01

The selective separation of Y from yttrium solution containing small heavy rare earth (HRE) impurities (Ho, Er, Tm, Yb, Lu) by liquid-liquid extraction using CA-100 in the presence of a water-soluble complexing agent of ethylenediaminetetraacetic acid (EDTA) was experimentally studied at 298 K. Experiments were carried out in two feeds, Feed-I: [RE] f = 4.94 x 10 -3 M, Y = 98.5%, HRE (Ho, Er, Tm, Yb, Lu) = 1.5%; Feed-II: [RE] f = 4.94 x 10 -3 M, Y = 99.9%, HRE (Ho, Er, Tm, Yb, Lu) = 0.1%, as a function of equilibrium pH (pH eq ), the concentration ratio of [EDTA]:[HRE impurities]. It was shown that the extraction of HRE in the presence of EDTA was suppressed when compared to that of Y because of the masking effect, while the selective extraction of Y was enhanced and the separation factors increased to maximum at appropriate condition for Feed-I: Y/Ho = 1.53, Y/Er 3.09, Y/Tm = 5.61, Y/Yb = 12.04, Y/Lu = 27.51 at pH 4.37 and [EDTA]:[HRE impurities] = 4:1, for Feed-II: Y/Ho = 1.32, Y/Er = 1.91, Y/Tm = 2.00, Y/Yb 3.05, Y/Lu = 3.33 at pH 4.42 and [EDTA]:[HRE impurities] = 8:1. The separation and purification of Y by this method was discussed

RIBOSOMAL COMPLEX IN PROPHYLAXIS AND TREATMENT OF ACUTE RESPIRATORY INFECTIONS IN CHILDREN

Directory of Open Access Journals (Sweden)

A.A. Alekseeva

2010-01-01

Full Text Available Acute respiratory infections (ARI are widespread in children regardless of age and region of living; they are characterized with big amount of infectious agents and absence of a trend to morbidity decrease. Drugs for nonspecific prophylaxis (immunostimulators and immunomodulatory agents are frequently used for prevention of ARI. There are plenty of immunomodulating agents; the wellstudied medication with systemic action with good efficacy and safety in pediatric practice is ribosomal-proteoglycan complex. The article presents the description of clinical experience of treatment with this complex in pediatric practice.Key words: children, acute respiratory infections, prophylaxis, treatment, ribosomal complex.(Voprosy sovremennoi pediatrii — Current Pediatrics. 2010;9(6:127-130

Hafnium-Based Contrast Agents for X-ray Computed Tomography.

Science.gov (United States)

Berger, Markus; Bauser, Marcus; Frenzel, Thomas; Hilger, Christoph Stephan; Jost, Gregor; Lauria, Silvia; Morgenstern, Bernd; Neis, Christian; Pietsch, Hubertus; Sülzle, Detlev; Hegetschweiler, Kaspar

2017-05-15

Heavy-metal-based contrast agents (CAs) offer enhanced X-ray absorption for X-ray computed tomography (CT) compared to the currently used iodinated CAs. We report the discovery of new lanthanide and hafnium azainositol complexes and their optimization with respect to high water solubility and stability. Our efforts culminated in the synthesis of BAY-576, an uncharged hafnium complex with 3:2 stoichiometry and broken complex symmetry. The superior properties of this asymmetrically substituted hafnium CA were demonstrated by a CT angiography study in rabbits that revealed excellent signal contrast enhancement.

Metal complex-based templates and nanostructures for magnetic resonance/optical multimodal imaging agents

NARCIS (Netherlands)

Galindo Millan, Jealemy

2012-01-01

In this thesis, new approaches directed towards simple and functional imaging agents (IAs) for magnetic resonance (MR) and fluorescence multimodal imaging are proposed. In Chapter 3, hybrid silver nanostructures (hAgNSs), grown using a polyamino carboxylic acid scaffold, namely

Can uranyl complexes encapsulate to carbon nanotubes? A ...

Indian Academy of Sciences (India)

K SRINIVASU

We find that uranyl-aqua complex ([UO2(H2O)5]2+) binds stronger as compared to uranyl-hydroxo-complex .... until the maximum Hellmann–Feynman force on each atom ..... porters and near-infrared agents for selective cancer cell.

Complexation Effect on Redox Potential of Iron(III)-Iron(II) Couple: A Simple Potentiometric Experiment

Science.gov (United States)

Rizvi, Masood Ahmad; Syed, Raashid Maqsood; Khan, Badruddin

2011-01-01

A titration curve with multiple inflection points results when a mixture of two or more reducing agents with sufficiently different reduction potentials are titrated. In this experiment iron(II) complexes are combined into a mixture of reducing agents and are oxidized to the corresponding iron(III) complexes. As all of the complexes involve the…

Intelligent agents for training on-board fire fighting

NARCIS (Netherlands)

Bosch, K. van den; Harbers, M.; Heuvelink, A.; Doesburg, W. van

2009-01-01

Simulation-based training in complex decision making often requires ample personnel for playing various roles (e.g. team mates, adversaries). Using intelligent agents may diminish the need for staff. However, to achieve goal-directed training, events in the simulation as well as the behavior of key

Mobile Agent-Based Software Systems Modeling Approaches: A Comparative Study

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Aissam Belghiat

2016-06-01

Full Text Available Mobile agent-based applications are special type of software systems which take the advantages of mobile agents in order to provide a new beneficial paradigm to solve multiple complex problems in several fields and areas such as network management, e-commerce, e-learning, etc. Likewise, we notice lack of real applications based on this paradigm and lack of serious evaluations of their modeling approaches. Hence, this paper provides a comparative study of modeling approaches of mobile agent-based software systems. The objective is to give the reader an overview and a thorough understanding of the work that has been done and where the gaps in the research are.

Validating agent oriented methodology (AOM) for netlogo modelling and simulation

Science.gov (United States)

WaiShiang, Cheah; Nissom, Shane; YeeWai, Sim; Sharbini, Hamizan

2017-10-01

AOM (Agent Oriented Modeling) is a comprehensive and unified agent methodology for agent oriented software development. AOM methodology was proposed to aid developers with the introduction of technique, terminology, notation and guideline during agent systems development. Although AOM methodology is claimed to be capable of developing a complex real world system, its potential is yet to be realized and recognized by the mainstream software community and the adoption of AOM is still at its infancy. Among the reason is that there are not much case studies or success story of AOM. This paper presents two case studies on the adoption of AOM for individual based modelling and simulation. It demonstrate how the AOM is useful for epidemiology study and ecological study. Hence, it further validate the AOM in a qualitative manner.

Comparison of Binding Affinities of Water-Soluble Calixarenes with the Organophosphorus Nerve Agent Soman (GD and Commonly-Used Nerve Agent Simulants

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Jayne A. Ede

2018-01-01

Full Text Available The formation of inclusion complexes of the water-soluble p-sulfonatocalix[n]arenes, where n = 4 or 6, with the Chemical Warfare Agent (CWA GD, or Soman, and commonly used dialkyl methylphosphonate simulants has been studied by experimental solution NMR methods and by Molecular Mechanics (MMFF and semi-empirical (PM6 calculations. Complex formation in non-buffered and buffered solutions is driven by the hydrophobic effect, and complex stoichiometry determined as 1:1 for all host:guest pairs. Low affinity complexes (Kassoc < 100 M−1 are observed for all guests, attributed to poor host–guest complementarity and the role of buffer cation species accounts for the low affinity of the complexes. Comparison of CWA and simulant behavior adds to understanding of CWA–simulant correlations and the challenges of simulant selection.

Agent Based Knowledge Management Solution using Ontology, Semantic Web Services and GIS

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Andreea DIOSTEANU

2009-01-01

Full Text Available The purpose of our research is to develop an agent based knowledge management application framework using a specific type of ontology that is able to facilitate semantic web service search and automatic composition. This solution can later on be used to develop complex solutions for location based services, supply chain management, etc. This application for modeling knowledge highlights the importance of agent interaction that leads to efficient enterprise interoperability. Furthermore, it proposes an "agent communication language" ontology that extends the OWL Lite standard approach and makes it more flexible in retrieving proper data for identifying the agents that can best communicate and negotiate.

Development of more efficacious Tc-99m organ imaging agents for use in nuclear medicine by analytical characterization of radiopharmaceutical mixtures

International Nuclear Information System (INIS)

Heineman, W.R.

1992-01-01

The long-range objective of this research program is the development of more efficacious technetium-99m radiopharmaceuticals for use as imaging agents in diagnostic nuclear medicine. We seek to isolate and develop distinct site imaging agents, each of which has properties optimized to provide diagnostic information concerning a given pathological condition. The specific objectives during the period (9/1/89 to 8/31/92) include: (1) Development of strategies for improving yields of specific Tc-diphosphonate complexes with optimum imaging properties; (2) Development of electrodes for rapid in situ electrochemical generation of skeletal imaging agents; (3) Development of electrochemical sensors for T c and Re imaging agents; (4) Characterization of stable T c - and Re-diphosphonate complexes obtainable in high yield by structural studies with techniques such as NMR, EXAFS, and Raman spectroscopy; (5) Development of improved separation techniques for the characterization of diphosphonate skeletal imaging agents; (6) Evaluation of the effect of the biological milieu on T c -diphosphonate complexes; and (7) Electrochemical studies of technetium and rhenium complexes synthesized by Professor Deutsch's research group for heart and brain imaging

Multimodal Corpus Analysis as a Method for Ensuring Cultural Usability of Embodied Conversational Agents

DEFF Research Database (Denmark)

Nakano, Yukiko; Rehm, Matthias

2009-01-01

In this paper we propose the method of multimodal corpus analysis to collect enough empirical data for modeling the behavior of embodied conversational agents. This is a prerequisite to ensure the usability of such complex interactive systems. So far, the development of embodied agents suffers fr...

Synthesis and characterization of lead sulphide thin films from ethanolamine (ETA) complexing agent chemical bath

Science.gov (United States)

Gashaw Hone, Fekadu; Dejene, F. B.

2018-02-01

Polycrystalline lead sulphide (PbS) thin films were grown on glass substrates by chemical bath deposition route using ethanolamine (ETA) as a complexing agent. The effects of ETA molar concentration on the structural, morphological, electrical and optical properties of lead sulphide thin films were thoroughly studied. The XRD analyses revealed that all the deposited thin films were face center cubic crystal structure and their preferred orientations were varied along the (111) and (200) planes. The XRD results further confirmed that ETA concentration had a significant effects on the strain, average crystalline size and dislocation density of the deposited thin films. The SEM studies illustrated the evolution and transformation of surface morphology as ETA molar concentration increased from 0.41 M to 1.64 M. The energy dispersive x-ray analysis was used to verify the compositional elements of the deposited thin films. Optical spectroscopy investigation established that the band gap of the PbS thin films were reduced from 0.98 eV to 0.68 eV as ETA concentration increased. The photoluminescence spectra showed a well defined peak at 428 nm and shoulder around 468 nm for all PbS thin films. The electrical resistivity of the thin films found in the order of 103 Ω cm at room temperature and decreased as the ETA molar concentration was increased.

Conceptual Framework for Agent-Based Modeling of Customer-Oriented Supply Networks

OpenAIRE

Solano-Vanegas , Clara ,; Carrillo-Ramos , Angela; Montoya-Torres , Jairo ,

2015-01-01

Part 3: Collaboration Frameworks; International audience; Supply Networks (SN) are complex systems involving the interaction of different actors, very often, with different objectives and goals. Among the different existing modeling approaches, agent-based systems can properly represent the autonomous behavior of SN links and, simultaneously, observe the general response of the system as a result of individual actions. Most of research using agent-based modeling in SN focuses on production is...

Multiwalled carbon nanotube hybrids as MRI contrast agents

Directory of Open Access Journals (Sweden)

Nikodem Kuźnik

2016-07-01

Full Text Available Magnetic resonance imaging (MRI is one of the most commonly used tomography techniques in medical diagnosis due to the non-invasive character, the high spatial resolution and the possibility of soft tissue imaging. Contrast agents, such as gadolinium complexes and superparamagnetic iron oxides, are administered to spotlight certain organs and their pathologies. Many new models have been proposed that reduce side effects and required doses of these already clinically approved contrast agents. These new candidates often possess additional functionalities, e.g., the possibility of bioactivation upon action of particular stimuli, thus serving as smart molecular probes, or the coupling with therapeutic agents and therefore combining both a diagnostic and therapeutic role. Nanomaterials have been found to be an excellent scaffold for contrast agents, among which carbon nanotubes offer vast possibilities. The morphology of multiwalled carbon nanotubes (MWCNTs, their magnetic and electronic properties, the possibility of different functionalization and the potential to penetrate cell membranes result in a unique and very attractive candidate for a new MRI contrast agent. In this review we describe the different issues connected with MWCNT hybrids designed for MRI contrast agents, i.e., their synthesis and magnetic and dispersion properties, as well as both in vitro and in vivo behavior, which is important for diagnostic purposes. An introduction to MRI contrast agent theory is elaborated here in order to point to the specific expectations regarding nanomaterials. Finally, we propose a promising, general model of MWCNTs as MRI contrast agent candidates based on the studies presented here and supported by appropriate theories.

Markov chain aggregation for agent-based models

CERN Document Server

Banisch, Sven

2016-01-01

This self-contained text develops a Markov chain approach that makes the rigorous analysis of a class of microscopic models that specify the dynamics of complex systems at the individual level possible. It presents a general framework of aggregation in agent-based and related computational models, one which makes use of lumpability and information theory in order to link the micro and macro levels of observation. The starting point is a microscopic Markov chain description of the dynamical process in complete correspondence with the dynamical behavior of the agent-based model (ABM), which is obtained by considering the set of all possible agent configurations as the state space of a huge Markov chain. An explicit formal representation of a resulting “micro-chain” including microscopic transition rates is derived for a class of models by using the random mapping representation of a Markov process. The type of probability distribution used to implement the stochastic part of the model, which defines the upd...

The need for and development of behaviourally realistic agents

NARCIS (Netherlands)

Jager, W; Janssen, M; Sichman, JS; Bousquet, F; Davidsson, P

2003-01-01

In this paper we argue that simulating complex systems involving human behaviour requires agent rules based on a theoretically rooted structure that captures basic behavioural processes. Essential components of such a structure involve needs, decision-making processes and learning. Such a structure

Multi-organ technetium complexes production and use thereof

International Nuclear Information System (INIS)

Koehler, G.A.; Pestel, G.M.

1976-01-01

Chemical complexes, useful as radiopharmaceuticals, are formed by reacting technetium-99m with substituted or unsubstituted alkyl monophosphonic acids and certain ester derivatives thereof. The complexes are formed by reducing pertechnetate ion chemically or electrolytically in the presence of the phosphonic acid. By chemical modification of the phosphonic acid complexing agent, it is possible to ''tailor'' complexes for kidney, liver or bone imaging. The complexes are normally used in a physiologically acceptable aqueous medium. 20 Claims, No Drawings

Complexity Intelligence and Cultural Coaching:

Directory of Open Access Journals (Sweden)

Jan Inglis

2005-06-01

Full Text Available In this article, we present the term complexity intelligence as a useful moniker to describe the reasoning ability, emotional capacity and social cognition necessary to meet the challenges of our prevailing life conditions. We suggest that, as a society and as individuals, we develop complexity intelligence as we navigate the gap between our current capacities and the capacities needed to respond to the next stage of complex challenges in our lives. We further suggest that it is possible to stimulate and support the emergence of complexity intelligence in a society, but we need a new form of social change agent - a cultural coach, to midwife its emergence.

A Multi-Agent Based Energy Management Solution for Integrated Buildings and Microgrid System

DEFF Research Database (Denmark)

Anvari-Moghaddam, Amjad; Rahimi-Kian, Ashkan; Mirian, Maryam S.

2017-01-01

-reflex to complex learning agents are designed and implemented to cooperate with each other to reach an optimal operating strategy for the mentioned integrated energy system (IES) while meeting the system’s objectives and related constraints. The optimization process for the EMS is defined as a coordinated......In this paper, an ontology-driven multi-agent based energy management system (EMS) is proposed for monitoring and optimal control of an integrated homes/buildings and microgrid system with various renewable energy resources (RESs) and controllable loads. Different agents ranging from simple...... distributed generation (DG) and demand response (DR) management problem within the studied environment and is solved by the proposed agent-based approach utilizing cooperation and communication among decision agents. To verify the effectiveness and applicability of the proposed multi-agent based EMS, several...

Polyaza macroligands as potential agents for heavy metal removal from wastewater

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Elizondo Martínez Perla

2013-01-01

Full Text Available Two polyaza macroligands N,N´-bis(2-aminobenzyl-1,2- ethanediamine (L1 and 3,6,9,12-tetraaza-4(1,2,11(1,2-dibenzo-1(1,3- piridinaciclotridecafano (L2 were characterized and investigated for their metal ion extraction capabilities. The nature of all complexes was established by spectroscopic techniques. The equilibrium constants were determined by spectrophotometric and potentiometric techniques and the residual concentration of metals in the solutions by Atomic Absorption Spectrometry (AAS. The capacity of the ligands to remove heavy metals such as Cu(II, Ni(II, Cd(II, Zn(II and Pb(II as insoluble complexes was evaluated in wastewater from industrial effluents. These agents showed high affinity for the studied metals. The values of equilibrium constants of the isolated complexes (between 1 x 104 and 2 x 107 demonstrated the feasibility of applying these chelating agents as an alternative to remove heavy metals from industrial effluents.

Smart Residential Buildings as Learning Agent Organizations in the Internet of Things

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Schatten Markus

2014-03-01

Full Text Available Background: Smart buildings are one of the major application areas of technologies bound to embedded systems and the Internet of things. Such systems have to be adaptable and flexible in order to provide better services to its residents. Modelling such systems is an open research question. Herein, the question is approached using an organizational modelling methodology bound to the principles of the learning organization. Objectives: Providing a higher level of abstraction for understanding, developing and maintaining smart residential buildings in a more human understandable form. Methods/Approach: Organization theory provides us with the necessary concepts and methodology to approach complex organizational systems. Results: A set of principles for building learning agent organizations, a formalization of learning processes for agents, a framework for modelling knowledge transfer between agents and the environment, and a tailored organizational structure for smart residential buildings based on Nonaka’s hypertext organizational form. Conclusions: Organization theory is a promising field of research when dealing with complex engineering systems

Complexity Results in Epistemic Planning

DEFF Research Database (Denmark)

Bolander, Thomas; Jensen, Martin Holm; Schwarzentruber, Francois

2015-01-01

Epistemic planning is a very expressive framework that extends automated planning by the incorporation of dynamic epistemic logic (DEL). We provide complexity results on the plan existence problem for multi-agent planning tasks, focusing on purely epistemic actions with propositional preconditions...

Competing intermolecular interactions of artemisinin-type agents and aspirin with membrane phospholipids: Combined model mass spectrometry and quantum-chemical study

International Nuclear Information System (INIS)

Pashynska, Vlada; Stepanian, Stepan; Gömöry, Agnes; Vekey, Karoly; Adamowicz, Ludwik

2015-01-01

Highlights: • Competitive binding of artemisinin agents and aspirin with phospholipids is shown. • Complexation between the antimalarial drugs and aspirin molecules is also found. • Energetically favorable structures of the model complexes are identified by DFT. • Membranotropic activity of the studied drugs can be modified under joint usage. - Abstract: Study of intermolecular interactions of antimalarial artemisinin-type drugs and aspirin with membrane phospholipids is important in term of elucidation of the drugs activity modification under their joint usage. Combined experimental and computational study of the interaction of dihydroartemisinin, α-artemether, and artesunate with aspirin (ASP) and dipalmitoylphosphatidylcholine (DPPC) is performed by electrospray ionization (ESI) mass spectrometry and by DFT B3LYP/aug-cc-pVDZ methods. The results of the ESI investigation of systems containing artemisinin-type agent, ASP and DPPC, reveal a competition between the antimalarial agents and ASP for binding with DPPC molecules. The complexation between the antimalarial drugs and ASP is also found. Observed phenomena suggest that membranotropic activity of artemisin-type agents and aspirin is modified under their combined usage. To elucidate structure-energy characteristics of the non-covalent complexes studied the model DFT calculations are performed for dihydroartemisinin · ASP complex and complexes of the each drug with phosphatidylcholine head of DPPC in neutral and cationized forms

Competing intermolecular interactions of artemisinin-type agents and aspirin with membrane phospholipids: Combined model mass spectrometry and quantum-chemical study

Energy Technology Data Exchange (ETDEWEB)

Pashynska, Vlada, E-mail: vlada@vl.kharkov.ua [B.Verkin Institute for Low Temperature Physics and Engineering of the National Academy of Sciences of Ukraine, Lenin Ave., 47, 61103 Kharkov (Ukraine); Stepanian, Stepan [B.Verkin Institute for Low Temperature Physics and Engineering of the National Academy of Sciences of Ukraine, Lenin Ave., 47, 61103 Kharkov (Ukraine); Gömöry, Agnes; Vekey, Karoly [Institute of Organic Chemistry of Research Centre for Natural Sciences of the Hungarian Academy of Sciences, Magyar tudosok korutja, 2, Budapest H-1117 (Hungary); Adamowicz, Ludwik [University of Arizona, Department of Chemistry and Biochemistry, Tucson, AZ 85721 (United States)

2015-07-09

Highlights: • Competitive binding of artemisinin agents and aspirin with phospholipids is shown. • Complexation between the antimalarial drugs and aspirin molecules is also found. • Energetically favorable structures of the model complexes are identified by DFT. • Membranotropic activity of the studied drugs can be modified under joint usage. - Abstract: Study of intermolecular interactions of antimalarial artemisinin-type drugs and aspirin with membrane phospholipids is important in term of elucidation of the drugs activity modification under their joint usage. Combined experimental and computational study of the interaction of dihydroartemisinin, α-artemether, and artesunate with aspirin (ASP) and dipalmitoylphosphatidylcholine (DPPC) is performed by electrospray ionization (ESI) mass spectrometry and by DFT B3LYP/aug-cc-pVDZ methods. The results of the ESI investigation of systems containing artemisinin-type agent, ASP and DPPC, reveal a competition between the antimalarial agents and ASP for binding with DPPC molecules. The complexation between the antimalarial drugs and ASP is also found. Observed phenomena suggest that membranotropic activity of artemisin-type agents and aspirin is modified under their combined usage. To elucidate structure-energy characteristics of the non-covalent complexes studied the model DFT calculations are performed for dihydroartemisinin · ASP complex and complexes of the each drug with phosphatidylcholine head of DPPC in neutral and cationized forms.

Study of occupational risk agents and its probable hazards to human health

International Nuclear Information System (INIS)

Carneiro, Janete Cristina G. Gaburo; Alves, Alice dos Santos; Sanches, Matias P.

2013-01-01

Currently the workplaces become increasingly complex and a strategy evaluation and the control of occupational risks agents is needed. Workers may be exposed to environmental agents (chemical, physical and biological) and other unsuitable conditions by performing tasks that involve these agents directly. The main objective of this study is to approach conceptual aspects of risk conditions, physical in nature, with emphasis on ionizing radiation and its interaction with other agents in occupational and environmental situations. To meet this goal, it is performed a literature review and a summary of the main occupational agents known or suspected to cause any adverse health effects in humans. According to the available literature the reported studies on the effects of combined exposures to radiation and others agents are recognized and, as far as possible, should be taken into account in evaluating of the potential radiation risks at low levels of exposure. (author)

A QUANTITATIVE FRAMEWORK FOR EARLY PREDICTION OF COOPERATION IN MULTI-AGENT SYSTEMS

Directory of Open Access Journals (Sweden)

S. Ajitha

2013-07-01

Full Text Available A Multi-Agent System (MAS is a system composed of multiple interacting intelligent agents. MAS can be used to solve problems that are difficult or impossible for an individual agent to solve. The different characteristics of MAS help in solving highly complex distributed problems. One of the important characteristics of MAS is its cooperative nature. This character helps different agents to interact with each other by exchanging messages. One of the major challenges in MAS is quantifying the cooperation between agents. This paper presents a framework for the quantification of cooperation between agents in MAS. We propose a methodology which helps to quantify the cooperation in the early stages of software development using a UML sequence diagram and a mathematical model. The proposed techniques are illustrated with the help of a case study. The numerical results we got were quite satisfactory.

Agent Programming Languages and Logics in Agent-Based Simulation

DEFF Research Database (Denmark)

Larsen, John

2018-01-01

and social behavior, and work on verification. Agent-based simulation is an approach for simulation that also uses the notion of agents. Although agent programming languages and logics are much less used in agent-based simulation, there are successful examples with agents designed according to the BDI...

Influence of complexing agent (Na2EDTA on chemical bath deposited Cu4SnS4 thin films

Directory of Open Access Journals (Sweden)

Anuar Kassim

2010-08-01

Full Text Available The quality of thin film is influenced by the presence of complexing agents such as Na2EDTA. The Cu4SnS4 thin films were deposited onto indium tin oxide glass substrate by chemical bath deposition method. The structural, morphological and optical properties of the deposited films have been studied using X-ray diffraction, atomic force microscopy and UV-Vis spectrophotometer, respectively. The XRD data showed that the films have a polycrystalline and orthorhombic structure. It also indicated that the most intense peak at 2 θ = 30.2° which belongs to (221 plane of Cu4 SnS4. The film deposited with 0.05 M Na2 EDTA showed good uniformity, good surface coverage with bigger grains and produced higher absorbance value. The band gap energy varies with the variation of Na2EDTA concentration which ranging from 1.56-1.60 eV. Deposition at concentration of 0.05 M Na2EDTA proved to offer a reasonably good Cu4SnS4 thin film.

Cooperative control of multi-agent systems optimal and adaptive design approaches

CERN Document Server

Lewis, Frank L; Hengster-Movric, Kristian; Das, Abhijit

2014-01-01

Task complexity, communication constraints, flexibility and energy-saving concerns are all factors that may require a group of autonomous agents to work together in a cooperative manner. Applications involving such complications include mobile robots, wireless sensor networks, unmanned aerial vehicles (UAVs), spacecraft, and so on. In such networked multi-agent scenarios, the restrictions imposed by the communication graph topology can pose severe problems in the design of cooperative feedback control systems.  Cooperative control of multi-agent systems is a challenging topic for both control theorists and practitioners and has been the subject of significant recent research. Cooperative Control of Multi-Agent Systems extends optimal control and adaptive control design methods to multi-agent systems on communication graphs.  It develops Riccati design techniques for general linear dynamics for cooperative state feedback design, cooperative observer design, and cooperative dynamic output feedback design.  B...

Peptaibol, secondary-metabolite, and hydrophobin pattern of commercial biocontrol agents formulated with species of the Trichoderma harzianum complex.

Science.gov (United States)

Degenkolb, Thomas; Fog Nielsen, Kristian; Dieckmann, Ralf; Branco-Rocha, Fabiano; Chaverri, Priscila; Samuels, Gary J; Thrane, Ulf; von Döhren, Hans; Vilcinskas, Andreas; Brückner, Hans

2015-04-01

The production of bioactive polypeptides (peptaibiotics) in vivo is a sophisticated adaptation strategy of both mycoparasitic and saprotrophic Trichoderma species for colonizing and defending their natural habitats. This feature is of major practical importance, as the detection of peptaibiotics in plant-protective Trichoderma species, which are successfully used against economically relevant bacterial and fungal plant pathogens, certainly contributes to a better understanding of these complex antagonistic interactions. We analyzed five commercial biocontrol agents (BCAs), namely Canna(®) , Trichosan(®) , Vitalin(®) , Promot(®) WP, and TrichoMax(®) , formulated with recently described species of the Trichoderma harzianum complex, viz. T. afroharzianum, T. simmonsii, and T. guizhouense. By using the well-established, HPLC/MS-based peptaibiomics approach, it could unequivocally be demonstrated that all of these formulations contained new and recurrent peptaibols, i.e., peptaibiotics carrying an acetylated N-terminus, the C-terminus of which is reduced to a 1,2-amino alcohol. Their chain lengths, including the amino alcohol, were 11, 14, and 18 residues, respectively. Peptaibols were also to be the dominating secondary metabolites in plate cultures of the four strains obtained from four of the Trichoderma- based BCAs, contributing 95% of the UHPLC-UV/VIS peak areas and 99% of the total ion count MS peak area from solid media. Furthermore, species-specific hydrophobins, as well as non-peptaibiotic secondary metabolites, were detected, the latter being known for their antifungal, siderophore, or plant-growth-promoting activities. Notably, none of the isolates produced low-molecular weight mycotoxins. Copyright © 2015 Verlag Helvetica Chimica Acta AG, Zürich.

Quantifying the complexity of medical research.

Science.gov (United States)

Rodriguez-Esteban, Raul; Loging, William T

2013-11-15

A crucial phenomenon of our times is the diminishing marginal returns of investments in pharmaceutical research and development. A potential reason is that research into diseases is becoming increasingly complex, and thus more burdensome, for humans to handle. We sought to investigate whether we could measure research complexity by analyzing the published literature. Through the text mining of the publication record of multiple diseases, we have found that the complexity and novelty of disease research has been increasing over the years. Surprisingly, we have also found that research on diseases with higher publication rate does not possess greater complexity or novelty than that on less-studied diseases. We have also shown that the research produced about a disease can be seen as a differentiated area of knowledge within the wider biomedical research. For our analysis, we have conceptualized disease research as a parallel multi-agent search in which each scientific agent (a scientist) follows a search path based on a model of a disease. We have looked at trends in facts published for diseases, measured their diversity and turnover using the entropy measure and found similar patterns across disease areas. raul.rodriguez-esteban@roche.com.

Reorganizing Complex Network to Improve Large-Scale Multiagent Teamwork

Directory of Open Access Journals (Sweden)

Yang Xu

2014-01-01

Full Text Available Large-scale multiagent teamwork has been popular in various domains. Similar to human society infrastructure, agents only coordinate with some of the others, with a peer-to-peer complex network structure. Their organization has been proven as a key factor to influence their performance. To expedite team performance, we have analyzed that there are three key factors. First, complex network effects may be able to promote team performance. Second, coordination interactions coming from their sources are always trying to be routed to capable agents. Although they could be transferred across the network via different paths, their sources and sinks depend on the intrinsic nature of the team which is irrelevant to the network connections. In addition, the agents involved in the same plan often form a subteam and communicate with each other more frequently. Therefore, if the interactions between agents can be statistically recorded, we are able to set up an integrated network adjustment algorithm by combining the three key factors. Based on our abstracted teamwork simulations and the coordination statistics, we implemented the adaptive reorganization algorithm. The experimental results briefly support our design that the reorganized network is more capable of coordinating heterogeneous agents.

Macrocyclic bis(ureas as ligands for anion complexation

Directory of Open Access Journals (Sweden)

Claudia Kretschmer

2014-08-01

Full Text Available Two macrocyclic bis(ureas 1 and 2, both based on diphenylurea, have been synthesized. Compound 1 represents the smaller ring with two ethynylene groups as linkers and 2 the larger ring with two butadiynylene groups. On thermal treatment to 130 °C molecule 1 splits up into two dihydroindoloquinolinone (3 molecules. Both compounds 1 and 2 form adducts with polar molecules such as dimethyl sulfoxide (DMSO and dimethylformamide (DMF and act as complexing agents towards a series of anions (Cl−, Br−, I−, NO3−, HSO4−. The crystal structures of 3, 2·2DMSO, 2·2DMF, and of the complex NEt4[Br·2] have been determined. Quantitative investigations of the complexation equilibria were performed via 1H NMR titrations. While 1 is a rather weak complexing agent, the large ring of 2 binds anions with association constants up to log K = 7.93 for chloride ions.

Controlling collective dynamics in complex minority-game resource-allocation systems

Science.gov (United States)

Zhang, Ji-Qiang; Huang, Zi-Gang; Dong, Jia-Qi; Huang, Liang; Lai, Ying-Cheng

2013-05-01

Resource allocation takes place in various kinds of real-world complex systems, such as traffic systems, social services institutions or organizations, or even ecosystems. The fundamental principle underlying complex resource-allocation dynamics is Boolean interactions associated with minority games, as resources are generally limited and agents tend to choose the least used resource based on available information. A common but harmful dynamical behavior in resource-allocation systems is herding, where there are time intervals during which a large majority of the agents compete for a few resources, leaving many other resources unused. Accompanying the herd behavior is thus strong fluctuations with time in the number of resources being used. In this paper, we articulate and establish that an intuitive control strategy, namely pinning control, is effective at harnessing the herding dynamics. In particular, by fixing the choices of resources for a few agents while leaving the majority of the agents free, herding can be eliminated completely. Our investigation is systematic in that we consider random and targeted pinning and a variety of network topologies, and we carry out a comprehensive analysis in the framework of mean-field theory to understand the working of control. The basic philosophy is then that, when a few agents waive their freedom to choose resources by receiving sufficient incentives, the majority of the agents benefit in that they will make fair, efficient, and effective use of the available resources. Our work represents a basic and general framework to address the fundamental issue of fluctuations in complex dynamical systems with significant applications to social, economical, and political systems.

Agents unleashed a public domain look at agent technology

CERN Document Server

Wayner, Peter

1995-01-01

Agents Unleashed: A Public Domain Look at Agent Technology covers details of building a secure agent realm. The book discusses the technology for creating seamlessly integrated networks that allow programs to move from machine to machine without leaving a trail of havoc; as well as the technical details of how an agent will move through the network, prove its identity, and execute its code without endangering the host. The text also describes the organization of the host's work processing an agent; error messages, bad agent expulsion, and errors in XLISP-agents; and the simulators of errors, f

Multifunctional ultra-high vacuum apparatus for studies of the interactions of chemical warfare agents on complex surfaces

International Nuclear Information System (INIS)

Wilmsmeyer, Amanda R.; Morris, John R.; Gordon, Wesley O.; Mantooth, Brent A.; Lalain, Teri A.; Davis, Erin Durke

2014-01-01

A fundamental understanding of the surface chemistry of chemical warfare agents is needed to fully predict the interaction of these toxic molecules with militarily relevant materials, catalysts, and environmental surfaces. For example, rules for predicting the surface chemistry of agents can be applied to the creation of next generation decontaminants, reactive coatings, and protective materials for the warfighter. Here, we describe a multifunctional ultra-high vacuum instrument for conducting comprehensive studies of the adsorption, desorption, and surface chemistry of chemical warfare agents on model and militarily relevant surfaces. The system applies reflection-absorption infrared spectroscopy, x-ray photoelectron spectroscopy, and mass spectrometry to study adsorption and surface reactions of chemical warfare agents. Several novel components have been developed to address the unique safety and sample exposure challenges that accompany the research of these toxic, often very low vapor pressure, compounds. While results of vacuum-based surface science techniques may not necessarily translate directly to environmental processes, learning about the fundamental chemistry will begin to inform scientists about the critical aspects that impact real-world applications

Multifunctional ultra-high vacuum apparatus for studies of the interactions of chemical warfare agents on complex surfaces.

Science.gov (United States)

Wilmsmeyer, Amanda R; Gordon, Wesley O; Davis, Erin Durke; Mantooth, Brent A; Lalain, Teri A; Morris, John R

2014-01-01

A fundamental understanding of the surface chemistry of chemical warfare agents is needed to fully predict the interaction of these toxic molecules with militarily relevant materials, catalysts, and environmental surfaces. For example, rules for predicting the surface chemistry of agents can be applied to the creation of next generation decontaminants, reactive coatings, and protective materials for the warfighter. Here, we describe a multifunctional ultra-high vacuum instrument for conducting comprehensive studies of the adsorption, desorption, and surface chemistry of chemical warfare agents on model and militarily relevant surfaces. The system applies reflection-absorption infrared spectroscopy, x-ray photoelectron spectroscopy, and mass spectrometry to study adsorption and surface reactions of chemical warfare agents. Several novel components have been developed to address the unique safety and sample exposure challenges that accompany the research of these toxic, often very low vapor pressure, compounds. While results of vacuum-based surface science techniques may not necessarily translate directly to environmental processes, learning about the fundamental chemistry will begin to inform scientists about the critical aspects that impact real-world applications.

Multifunctional ultra-high vacuum apparatus for studies of the interactions of chemical warfare agents on complex surfaces

Energy Technology Data Exchange (ETDEWEB)

Wilmsmeyer, Amanda R.; Morris, John R. [Department of Chemistry, Virginia Tech, Blacksburg, Virginia 24061 (United States); Gordon, Wesley O.; Mantooth, Brent A.; Lalain, Teri A. [Research and Technology Directorate, U.S. Army Edgewood Chemical Biological Center, Aberdeen Proving Ground, Maryland 21010 (United States); Davis, Erin Durke [OptiMetrics, Inc., Abingdon, Maryland 21009 (United States)

2014-01-15

A fundamental understanding of the surface chemistry of chemical warfare agents is needed to fully predict the interaction of these toxic molecules with militarily relevant materials, catalysts, and environmental surfaces. For example, rules for predicting the surface chemistry of agents can be applied to the creation of next generation decontaminants, reactive coatings, and protective materials for the warfighter. Here, we describe a multifunctional ultra-high vacuum instrument for conducting comprehensive studies of the adsorption, desorption, and surface chemistry of chemical warfare agents on model and militarily relevant surfaces. The system applies reflection-absorption infrared spectroscopy, x-ray photoelectron spectroscopy, and mass spectrometry to study adsorption and surface reactions of chemical warfare agents. Several novel components have been developed to address the unique safety and sample exposure challenges that accompany the research of these toxic, often very low vapor pressure, compounds. While results of vacuum-based surface science techniques may not necessarily translate directly to environmental processes, learning about the fundamental chemistry will begin to inform scientists about the critical aspects that impact real-world applications.

Consentaneous agent-based and stochastic model of the financial markets.

Science.gov (United States)

Gontis, Vygintas; Kononovicius, Aleksejus

2014-01-01

We are looking for the agent-based treatment of the financial markets considering necessity to build bridges between microscopic, agent based, and macroscopic, phenomenological modeling. The acknowledgment that agent-based modeling framework, which may provide qualitative and quantitative understanding of the financial markets, is very ambiguous emphasizes the exceptional value of well defined analytically tractable agent systems. Herding as one of the behavior peculiarities considered in the behavioral finance is the main property of the agent interactions we deal with in this contribution. Looking for the consentaneous agent-based and macroscopic approach we combine two origins of the noise: exogenous one, related to the information flow, and endogenous one, arising form the complex stochastic dynamics of agents. As a result we propose a three state agent-based herding model of the financial markets. From this agent-based model we derive a set of stochastic differential equations, which describes underlying macroscopic dynamics of agent population and log price in the financial markets. The obtained solution is then subjected to the exogenous noise, which shapes instantaneous return fluctuations. We test both Gaussian and q-Gaussian noise as a source of the short term fluctuations. The resulting model of the return in the financial markets with the same set of parameters reproduces empirical probability and spectral densities of absolute return observed in New York, Warsaw and NASDAQ OMX Vilnius Stock Exchanges. Our result confirms the prevalent idea in behavioral finance that herding interactions may be dominant over agent rationality and contribute towards bubble formation.

Discerning in situ performance of an eor agent in the midst of geological uncertainty

NARCIS (Netherlands)

Fatemi, S.A.; Jansen, J.D.; Rossen, W.R.

2015-01-01

An enhanced-oil-recovery pilot test has multiple goals, among them to verify the properties of the EOR agent in situ. Given the complexity of EOR processes and the inherent uncertainty in the reservoir description, it is a challenge to discern the properties of the EOR agent in situ. We present a

Simulation and Analysis of Complex Biological Processes: an Organisation Modelling Perspective

NARCIS (Netherlands)

Bosse, T.; Jonker, C.M.; Treur, J.

2005-01-01

This paper explores how the dynamics of complex biological processes can be modelled and simulated as an organisation of multiple agents. This modelling perspective identifies organisational structure occurring in complex decentralised processes and handles complexity of the analysis of the dynamics

Patterns of cooperation: fairness and coordination in networks of interacting agents

Science.gov (United States)

Do, Anne-Ly; Rudolf, Lars; Gross, Thilo

2010-06-01

We study the self-assembly of a complex network of collaborations among self-interested agents. The agents can maintain different levels of cooperation with different partners. Further, they continuously, selectively and independently adapt the amount of resources allocated to each of their collaborations in order to maximize the obtained payoff. We show analytically that the system approaches a state in which the agents make identical investments, and links produce identical benefits. Despite this high degree of social coordination, some agents manage to secure privileged topological positions in the network, enabling them to extract high payoffs. Our analytical investigations provide a rationale for the emergence of unidirectional non-reciprocal collaborations and different responses to the withdrawal of a partner from an interaction that have been reported in the psychological literature.

Synthesis of macrocyclic polyamines; complexation of basic [{sup 99m}TcO{sub 2}{sup +}] and biodistribution of complexed forms; Synthese de polyamines macrocycliques. Complexation du coeur [{sup 99m}TcO{sub 2}{sup +}] et biodistribution des complexes formes

Energy Technology Data Exchange (ETDEWEB)

Riche, F.; Vidal, M. [Universite Joseph Fourier, 38 - Grenoble (France); Mathieu, J.P.; Fagret, D.; Comet, M. [Universite Joseph Fourier, 38 - La Tronche (France). Faculte de Medecine; Pasqualini, R. [CIS bio international, 91 - Gif-sur-Yvette (France)

1996-01-01

The synthesis of macrocyclic polyamines is described, as well as their complexation with technetium via pertechnetole ligands. Several pertechnetole reducing agents were studied, as well as their method of complexation with polyamines and their charge and lipophilicity. Their biodistribution in the mouse and the dog has been studied by scintiscanning which provides evidence of their excellence as hepatobiliary tracers. (UK).

Ruthenium (II) complexes of thiosemicarbazone: Synthesis, biosensor applications and evaluation as antimicrobial agents

International Nuclear Information System (INIS)

Yildirim, Hatice; Guler, Emine; Yavuz, Murat; Ozturk, Nurdan; Kose Yaman, Pelin; Subasi, Elif; Sahin, Elif; Timur, Suna

2014-01-01

A conformationally rigid half-sandwich organoruthenium (II) complex [(η 6 -p-cymene)RuClTSC N–S ]Cl, (1) and carbonyl complex [Ru(CO)Cl(PPh 3 ) 2 TSC N–S ] (2) have been synthesized from the reaction of [{(η 6 -p-cymene)RuCl} 2 (μ-Cl) 2 ] and [Ru(H)(Cl)(CO)(PPh 3 ) 3 ] with thiophene-2-carboxaldehyde thiosemicarbazon (TSC) respectively and both novel ruthenium (II) complexes have been characterized by elemental analysis, FT-IR and NMR spectroscopy. The peripheral TSC in the complexes acts as an electrochemical coupling unit providing the ability to carry out electrochemical deposition (ED) and to form an electro-deposited film on a graphite electrode surface. The biosensing applicability of complexes 1 and 2 was investigated by using glucose oxidase (GOx) as a model enzyme. Electrochemical measurements at − 0.9 V versus Ag/AgCl electrode by following the ED Ru(II) reduction/oxidation due to from the enzyme activity, in the presence of glucose substrate. The designed biosensor showed a very good linearity for 0.01–0.5 mM glucose. The in vitro antimicrobial activities of complexes 1 and 2 were also investigated against nine bacterial strains and one fungus by the disc diffusion test method. No activity was observed against the Gram-negative strains and fungus, whereas complex 1 showed moderate antibacterial activities against Gram-positive bacterial strains. - Highlights: • Novel Ru (II) thiosemicarbazone complexes were synthesized and characterized. • Electrochemical depositions were performed. • Rigid half-sandwich Ru (II) complex showed enhanced antibacterial activity

Framework for Securing Mobile Software Agents

OpenAIRE

Mwakalinga, G Jeffy; Yngström, Louise

2006-01-01

Information systems are growing in size and complexity making it infeasible for human administrators to manage them. The aim of this work is to study ways of securing and using mobile software agents to deter attackers, protect information systems, detect intrusions, automatically respond to the intrusions and attacks, and to produce recovery services to systems after attacks. Current systems provide intrusion detection, prevention, protection, response, and recovery services but most of thes...

Uses of Tc99m complexes

International Nuclear Information System (INIS)

Kubiatowicz, D.O.; Bolles, T.F.

1978-01-01

The invention deals with the use of a complex of the radioactive metastable isotope Tcsup(99m) together with water-soluble mercaptane for the preparation of a parenterally administered renal diagnostic agent. (VJ/orig.) [de

Mobile Agent Data Integrity Using Multi-Agent Architecture

National Research Council Canada - National Science Library

McDonald, Jeffrey

2004-01-01

.... Security issues for mobile agents continue to produce research interest, particularly in developing mechanisms that guarantee protection of agent data and agent computations in the presence of malicious hosts...

Endogenous Price Bubbles in a Multi-Agent System of the Housing Market.

Science.gov (United States)

Kouwenberg, Roy; Zwinkels, Remco C J

2015-01-01

Economic history shows a large number of boom-bust cycles, with the U.S. real estate market as one of the latest examples. Classical economic models have not been able to provide a full explanation for this type of market dynamics. Therefore, we analyze home prices in the U.S. using an alternative approach, a multi-agent complex system. Instead of the classical assumptions of agent rationality and market efficiency, agents in the model are heterogeneous, adaptive, and boundedly rational. We estimate the multi-agent system with historical house prices for the U.S. market. The model fits the data well and a deterministic version of the model can endogenously produce boom-and-bust cycles on the basis of the estimated coefficients. This implies that trading between agents themselves can create major price swings in absence of fundamental news.

Endogenous Price Bubbles in a Multi-Agent System of the Housing Market.

Directory of Open Access Journals (Sweden)

Roy Kouwenberg

Full Text Available Economic history shows a large number of boom-bust cycles, with the U.S. real estate market as one of the latest examples. Classical economic models have not been able to provide a full explanation for this type of market dynamics. Therefore, we analyze home prices in the U.S. using an alternative approach, a multi-agent complex system. Instead of the classical assumptions of agent rationality and market efficiency, agents in the model are heterogeneous, adaptive, and boundedly rational. We estimate the multi-agent system with historical house prices for the U.S. market. The model fits the data well and a deterministic version of the model can endogenously produce boom-and-bust cycles on the basis of the estimated coefficients. This implies that trading between agents themselves can create major price swings in absence of fundamental news.

Endogenous Price Bubbles in a Multi-Agent System of the Housing Market

Science.gov (United States)

2015-01-01

Economic history shows a large number of boom-bust cycles, with the U.S. real estate market as one of the latest examples. Classical economic models have not been able to provide a full explanation for this type of market dynamics. Therefore, we analyze home prices in the U.S. using an alternative approach, a multi-agent complex system. Instead of the classical assumptions of agent rationality and market efficiency, agents in the model are heterogeneous, adaptive, and boundedly rational. We estimate the multi-agent system with historical house prices for the U.S. market. The model fits the data well and a deterministic version of the model can endogenously produce boom-and-bust cycles on the basis of the estimated coefficients. This implies that trading between agents themselves can create major price swings in absence of fundamental news. PMID:26107740

Synthesis of ZnS films on Si(100) wafers by using chemical bath deposition assisted by the complexing agent ethylenediamine

Science.gov (United States)

Zhu, He-Jie; Wang, Xue-Mei; Gao, Xiao-Yong

2015-07-01

Low-cost synthesis of high-quality ZnS films on silicon wafers is of much importance to the ZnSbased heterojunction blue light-emitting device integrated with silicon. Thus, a series of ZnS films were chemically synthesized at low cost on Si(100) wafers at 353 K under a mixed acidic solution with a pH of 4 with zinc acetate and thioacetamide as precursors and with ethylenediamine and hydrochloric acid as the complexing agent and the pH value modifier, respectively. The effects of the ethylenediamine concentration on the crystallization, surface morphology, and optical properties of the ZnS films were investigated by using X-ray diffractometry, scanning electron microscopy, spectrophotometry, and fluorescence spectroscopy. A mechanism for the formation of ZnS film under an acidic condition was also proposed. All of the ZnS films were polycrystalline in nature, with a dominant cubic phase and a small amounts of hexagonal phases. The crystallization and the surface pattern of the films were clearly improved with increasing ethylenediamine concentration due to its enhanced complexing role. The absorption edge of the films almost underwent a blue shift with increasing ethylenediamine concentration, which was largely attributed to the quantum confinement effects caused by the small particle size of the polycrystalline ZnS films. Defect species and the corresponding strengths of the ZnS films were strongly affected by the ethylenediamine concentration.

A Novel Approach to Selecting Contractor in Agent-based Multi-sensor Battlefield Reconnaissance Simulation

Directory of Open Access Journals (Sweden)

Xiong Li

2012-11-01

Full Text Available This paper presents a novel approach towards showing how contractor in agent-based simulation for complex warfare system such as multi-sensor battlefield reconnaissance system can be selected in Contract Net Protocol (CNP with high efficiency. We first analyze agent and agent-based simulation framework, CNP and collaborators, and present agents interaction chain used to actualize CNP and establish agents trust network. We then obtain contractor's importance weight and dynamic trust by presenting fuzzy similarity-based algorithm and trust modifying algorithm, thus we propose contractor selecting approach based on maximum dynamic integrative trust. We validate the feasibility and capability of this approach by implementing simulation, analyzing compared results and checking the model.

Ruthenium (II) complexes of thiosemicarbazone: Synthesis, biosensor applications and evaluation as antimicrobial agents

Energy Technology Data Exchange (ETDEWEB)

Yildirim, Hatice [Dokuz Eylul University, The Graduate School of Natural and Applied Sciences, Department of Chemistry, 35160 Buca, Izmir (Turkey); Guler, Emine [Ege University, Faculty of Science, Department of Biochemistry, 35100 Bornova, Izmir (Turkey); Yavuz, Murat, E-mail: myavuz@dicle.edu.tr [Ege University, Faculty of Science, Department of Biochemistry, 35100 Bornova, Izmir (Turkey); Dicle University, Faculty of Science, Department of Chemistry, 21280 Diyarbakir (Turkey); Ozturk, Nurdan; Kose Yaman, Pelin [Dokuz Eylul University, The Graduate School of Natural and Applied Sciences, Department of Chemistry, 35160 Buca, Izmir (Turkey); Subasi, Elif; Sahin, Elif [Dokuz Eylul University, Faculty of Science, Department of Chemistry, 35160 Buca, Izmir (Turkey); Timur, Suna [Ege University, Faculty of Science, Department of Biochemistry, 35100 Bornova, Izmir (Turkey); Ege University, Institute on Drug Abuse, Toxicology and Pharmaceutical Science (BATI), 35100 Bornova, Izmir (Turkey)

2014-11-01

A conformationally rigid half-sandwich organoruthenium (II) complex [(η{sup 6}-p-cymene)RuClTSC{sup N–S}]Cl, (1) and carbonyl complex [Ru(CO)Cl(PPh{sub 3}){sub 2}TSC{sup N–S}] (2) have been synthesized from the reaction of [{(η"6-p-cymene)RuCl}{sub 2}(μ-Cl){sub 2}] and [Ru(H)(Cl)(CO)(PPh{sub 3}){sub 3}] with thiophene-2-carboxaldehyde thiosemicarbazon (TSC) respectively and both novel ruthenium (II) complexes have been characterized by elemental analysis, FT-IR and NMR spectroscopy. The peripheral TSC in the complexes acts as an electrochemical coupling unit providing the ability to carry out electrochemical deposition (ED) and to form an electro-deposited film on a graphite electrode surface. The biosensing applicability of complexes 1 and 2 was investigated by using glucose oxidase (GOx) as a model enzyme. Electrochemical measurements at − 0.9 V versus Ag/AgCl electrode by following the ED Ru(II) reduction/oxidation due to from the enzyme activity, in the presence of glucose substrate. The designed biosensor showed a very good linearity for 0.01–0.5 mM glucose. The in vitro antimicrobial activities of complexes 1 and 2 were also investigated against nine bacterial strains and one fungus by the disc diffusion test method. No activity was observed against the Gram-negative strains and fungus, whereas complex 1 showed moderate antibacterial activities against Gram-positive bacterial strains. - Highlights: • Novel Ru (II) thiosemicarbazone complexes were synthesized and characterized. • Electrochemical depositions were performed. • Rigid half-sandwich Ru (II) complex showed enhanced antibacterial activity.

Derivation of Continuum Models from An Agent-based Cancer Model: Optimization and Sensitivity Analysis.

Science.gov (United States)

Voulgarelis, Dimitrios; Velayudhan, Ajoy; Smith, Frank

2017-01-01

Agent-based models provide a formidable tool for exploring complex and emergent behaviour of biological systems as well as accurate results but with the drawback of needing a lot of computational power and time for subsequent analysis. On the other hand, equation-based models can more easily be used for complex analysis in a much shorter timescale. This paper formulates an ordinary differential equations and stochastic differential equations model to capture the behaviour of an existing agent-based model of tumour cell reprogramming and applies it to optimization of possible treatment as well as dosage sensitivity analysis. For certain values of the parameter space a close match between the equation-based and agent-based models is achieved. The need for division of labour between the two approaches is explored. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

[Comparative efficiency of nootropic drugs in complex treatment of patients with remote consequences of closed craniocereberal trauma].

Science.gov (United States)

Hliebova, O S; Tkachenko, O V

2008-01-01

Main data of the research were data obtained after a complex treatment of 120 persons with late consequences of closed craniocereberal trauma (CCRCT). The treatment included administration of one of nootropic agents (noophen, aminolon or entropil), magnesium sulfate, group B vitamins. All patients have passed a complex examination: specially developed questionnaire, anamnesis gathering, neurologic status, neuropsychological status with the use of multiple-aspect scales and questionnaires, examination of fundus of eye, rheoencephalography, echoencephalography, brain MRT. Results of a complex examination proved positive effect of the use of nootropic agents, in particular noophen, entropil and aminolon in complex treatment of late consequences of closed craniocereberal trauma. For optimisation of the use of nootropic agents in the treatment of late consequences of closed craniocereberal trauma it is recommended to consider features of influence of nootropic agents on certain clinical aspects of the disease.

The clinical educator and complexity: a review.

Science.gov (United States)

Schoo, Adrian; Kumar, Koshila

2018-02-08

Complexity science perspectives have helped in examining fundamental assumptions about learning and teaching in the health professions. The implications of complexity thinking for how we understand the role and development of the clinical educator is less well articulated. This review article outlines: the key principles of complexity science; a conceptual model that situates the clinical educator in a complex system; and the implications for the individual, organisation and the system. Our conceptual model situates the clinical educator at the centre of a complex and dynamic system spanning four domains and multiple levels. The four domains are: personal (encompassing personal/professional needs and expectations); health services (health agencies and their consumers); educational (educational institutions and their health students); and societal (local community/region and government). The system also comprises: micro or individual, meso or organisational, and macro or socio-political levels. Our model highlights that clinical educators are situated within a complex system comprising different agents and connections. It emphasises that individuals, teams and organisations need to recognise and be responsive to the unpredictability, interconnectedness and evolving nature of this system. Importantly, our article also calls for an epistemological shift from faculty development to capacity building in health professions education, aimed at developing individual, team, organisational and system capabilities to work with(in) complexity. Clinical educators are situated within a complex system comprising different agents and connections. © 2018 John Wiley & Sons Ltd and The Association for the Study of Medical Education.

Using Intelligent Agents to Manage Business Processes

OpenAIRE

Jennings, N. R.; Faratin, P.; Johnson, M. J.; O'Brien, P.; Wiegand, M. E.

1996-01-01

Management of the business process requires pertinent, consistent and up-to-date information gathering and information dissemination. These complex and time consuming tasks prompt organizations to develop an Information Technology system to assist with the management of various aspects of their business processes. Intelligent agents are the strongest solution candidates because of their many advantages, namely: autonomy, social ability, responsiveness and proactiveness. Given these characteri...

Application of Complex Adaptive Systems in Portfolio Management

Science.gov (United States)

Su, Zheyuan

2017-01-01

Simulation-based methods are becoming a promising research tool in financial markets. A general Complex Adaptive System can be tailored to different application scenarios. Based on the current research, we built two models that would benefit portfolio management by utilizing Complex Adaptive Systems (CAS) in Agent-based Modeling (ABM) approach.…

Synthesis and evaluation of gadolinium complexes based on PAMAM as MRI contrast agents.

Science.gov (United States)

Yan, Guo-Ping; Hu, Bin; Liu, Mai-Li; Li, Li-Yun

2005-03-01

Diethylenetriaminepentaacetic acid (DTPA) and pyridoxamine (PM) were incorporated into the amine groups on the surface of ammonia-core poly(amidoamine) dendrimers (PAMAM, Generation 2.0-5.0) to obtain dendritic ligands. These dendritic ligands were reacted with gadolinium chloride to yield the corresponding dendritic gadolinium (Gd) complexes. The dendritic ligands and their gadolinium complexes were characterized by(1)HNMR, IR, UV and elemental analysis. Relaxivity studies showed that the dendritic gadolinium complexes possessed higher relaxation effectiveness compared with the clinically used Gd-DTPA. After administration of the dendritic gadolinium complexes (0.09 mmol kg(-1) ) to rats, magnetic resonance imaging of the liver indicated that the dendritic gadolinium complexes containing pyridoxamine groups enhanced the contrast of the MR images of the liver, provided prolonged intravascular duration and produced highly contrasted visualization of blood vessels.

Complex adaptive systems and game theory: An unlikely union

Science.gov (United States)

Hadzikadic, M.; Carmichael, T.; Curtin, C.

2010-01-01

A Complex Adaptive System is a collection of autonomous, heterogeneous agents, whose behavior is defined with a limited number of rules. A Game Theory is a mathematical construct that assumes a small number of rational players who have a limited number of actions or strategies available to them. The CAS method has the potential to alleviate some of the shortcomings of GT. On the other hand, CAS researchers are always looking for a realistic way to define interactions among agents. GT offers an attractive option for defining the rules of such interactions in a way that is both potentially consistent with observed real-world behavior and subject to mathematical interpretation. This article reports on the results of an effort to build a CAS system that utilizes GT for determining the actions of individual agents. ?? 2009 Wiley Periodicals, Inc. Complexity, 16,24-42, 2010.

Agent based approach for engineering and control of micro-grids

International Nuclear Information System (INIS)

Basso, Gillian

2013-01-01

Energy management is, nowadays, a subject of uttermost importance. Indeed, we are facing growing concerns such as petroleum reserve depletion, earth global warming or power quality (e.g. avoiding blackouts during peak times). Smart grids is an attempt to solve such problems, by adding to power grids bidirectional communications and ICT capabilities in order to provide an intelligent autonomic management for the grid. This thesis focuses on the management of micro-grids thanks to multi-agent systems (MAS). Micro-grids are low-power networks, composed of small and decentralized energy producers (possibly renewable) and consumers. These networks can be connected to the main grid or islanded, this make them more complex. Due to their complexity and their geographical distribution, smart grids and micro-grids can not be easily managed by a centralized system. Distributed artificial intelligences especially MAS appear to be a solution to resolve problems related to smart grids. Firstly we defined an approach implementing feedback loops. These feedback loops exist in complex systems which can be defined with several abstraction levels. Two levels are interacting. The micro-level contains a set of agents owning behaviours that can be combined. The result of the combination impact the state of the system. The macro-level processes these influences to define a new state of the system which will impact the agents behaviours at the micro-level. This feedback loop separates behaviours on several levels. This approach is used to defined a demand and supply matching problem in micro-grid. This problem afford to manage a set of goals which currently are independently processed. Finally, an application is developed using MAS that ensures grid stability thanks to storage systems. This application was thought to be integrated to the approach detailed above. Secondly, a grid simulator id developed. This simulator allows dynamic control of devices. It is based on three main principles

Distance-Based Behaviors for Low-Complexity Control in Multiagent Robotics

Science.gov (United States)

Pierpaoli, Pietro

Several biological examples show that living organisms cooperate to collectively accomplish tasks impossible for single individuals. More importantly, this coordination is often achieved with a very limited set of information. Inspired by these observations, research on autonomous systems has focused on the development of distributed control techniques for control and guidance of groups of autonomous mobile agents, or robots. From an engineering perspective, when coordination and cooperation is sought in large ensembles of robotic vehicles, a reduction in hardware and algorithms' complexity becomes mandatory from the very early stages of the project design. The research for solutions capable of lowering power consumption, cost and increasing reliability are thus worth investigating. In this work, we studied low-complexity techniques to achieve cohesion and control on swarms of autonomous robots. Starting from an inspiring example with two-agents, we introduced effects of neighbors' relative positions on control of an autonomous agent. The extension of this intuition addressed the control of large ensembles of autonomous vehicles, and was applied in the form of a herding-like technique. To this end, a low-complexity distance-based aggregation protocol was defined. We first showed that our protocol produced a cohesion aggregation among the agent while avoiding inter-agent collisions. Then, a feedback leader-follower architecture was introduced for the control of the swarm. We also described how proximity measures and probability of collisions with neighbors can also be used as source of information in highly populated environments.

Reversal of rocuronium-induced neuromuscular block by the selective relaxant binding agent sugammadex: a dose-finding and safety study

DEFF Research Database (Denmark)

Sorgenfrei, Iben F; Norrild, Kathrine; Larsen, Per Bo

2006-01-01

Sugammadex (Org 25969) forms a complex with steroidal neuromuscular blocking agents, thereby reversing neuromuscular block. This study investigated the dose-response relation, safety, and pharmacokinetics of sugammadex to reverse rocuronium-induced block.......Sugammadex (Org 25969) forms a complex with steroidal neuromuscular blocking agents, thereby reversing neuromuscular block. This study investigated the dose-response relation, safety, and pharmacokinetics of sugammadex to reverse rocuronium-induced block....

A Multi Agent Based Approach for Prehospital Emergency Management.

Science.gov (United States)

Safdari, Reza; Shoshtarian Malak, Jaleh; Mohammadzadeh, Niloofar; Danesh Shahraki, Azimeh

2017-07-01

To demonstrate an architecture to automate the prehospital emergency process to categorize the specialized care according to the situation at the right time for reducing the patient mortality and morbidity. Prehospital emergency process were analyzed using existing prehospital management systems, frameworks and the extracted process were modeled using sequence diagram in Rational Rose software. System main agents were identified and modeled via component diagram, considering the main system actors and by logically dividing business functionalities, finally the conceptual architecture for prehospital emergency management was proposed. The proposed architecture was simulated using Anylogic simulation software. Anylogic Agent Model, State Chart and Process Model were used to model the system. Multi agent systems (MAS) had a great success in distributed, complex and dynamic problem solving environments, and utilizing autonomous agents provides intelligent decision making capabilities.  The proposed architecture presents prehospital management operations. The main identified agents are: EMS Center, Ambulance, Traffic Station, Healthcare Provider, Patient, Consultation Center, National Medical Record System and quality of service monitoring agent. In a critical condition like prehospital emergency we are coping with sophisticated processes like ambulance navigation health care provider and service assignment, consultation, recalling patients past medical history through a centralized EHR system and monitoring healthcare quality in a real-time manner. The main advantage of our work has been the multi agent system utilization. Our Future work will include proposed architecture implementation and evaluation of its impact on patient quality care improvement.

Use of equilibrium constant expression for initial screening of potential antithyroid agents

International Nuclear Information System (INIS)

Fatima, I.; Nanawar, M.A.; Tasneem, A.

2011-01-01

Synthetic antithyroid agents act through inhibition of enzyme or by making stable charge transfer (CT) complex with iodine. Iodine acts as s-acceptor and the synthetic compound as n-donor. Study of CT complexation of various drugs with iodine using UV/visible spectroscopy has revealed a positive correlation between the formation constant (Kc) and in vivo an activity. Some alkyl derivatives of 9H-purine-6-thiol were synthesized and evaluated in vitro as well as in vivo for potential antithyroid effects. The compounds exhibited 1:1 charge transfer complexation with iodine and have quite high values of formation constants. The blood assays of rats treated with these compounds and histological study of the thyroid tissues indicated the hyperactivity of gland. These compounds are expected to have lesser side effects as the sulfa group, a cause of toxicity in many medicines, is blocked. Phenyl derivative proved to be the most potent antithyroid agent comparable with methimazole. (author)

Comparative studies of the influence of cyclodextrins on the stability of the sunscreen agent, 2-ethylhexyl-p-methoxycinnamate.

Science.gov (United States)

Scalia, Santo; Casolari, Alberto; Iaconinoto, Antonietta; Simeoni, Silvia

2002-11-07

The effects of beta-cyclodextrin (beta-CD) and hydroxypropyl-beta-cyclodextrin (HP-beta-CD) on the base-catalyzed degradation and light-induced decomposition of the sunscreen agent, trans-2-ethylhexyl-p-methoxycinnamate (trans-EHMC) were investigated. Reversed-phase liquid chromatography was used to study the interaction between natural and modified cyclodextrins, added to the mobile phase, and the sunscreen. Among the available cyclodextrins (beta-CD, HP-beta-CD, hydroxypropyl-alpha-cyclodextrin and hydroxypropyl-gamma-cyclodextrin), only HP-beta-CD and beta-CD produced a significant decrease in the chromatographic retention of trans-EHMC. The complexation of the sunscreen agent with HP-beta-CD and beta-CD was confirmed by thermal analysis and nuclear magnetic resonance spectroscopy. beta-CD depressed the decomposition of trans-EHMC in alkaline solutions more effectively than HP-beta-CD. Moreover, the irradiation-induced degradation of the sunscreen agent in emulsion vehicles was reduced by complexation with beta-CD (the extent of degradation was 26.1% for the complex compared to 35.8% for free trans-EHMC) whereas HP-beta-CD had no significant effect. Therefore, the complex of beta-CD with trans-EHMC enhances the chemical- and photo-stability of the sunscreen agent. Moreover, it limits adverse interactions of the UV filter with other formulation ingredients.

Pharmacology of dimethanesulfonate alkylating agents: busulfan and treosulfan.

Science.gov (United States)

Galaup, Ariane; Paci, Angelo

2013-03-01

Among the dimethanesulfonates, busulfan, in combination with other alkylating agents or nucleoside analogues, is the cornerstone of high-dose chemotherapy. It is used, and followed hematopoietic stem cell transplantation, for the treatment of various hematologic malignancies and immunodeficiencies. Treosulfan, which is a hydrophilic analogue of busulfan, was the first dimethanesufonate registered for the treatment of ovarian cancer. Recently, treosulfan has been investigated for the treatment of hematologic malignancies in combination with the same second agents before hematopoietic stem cell transplantation. This work reviews the pharmacological data of these two dimethanesulfonates alkylating agents. Specifically, the article looks at their chemistry, metabolism, anticancer activity, and their pharmacokinetics and pharmacodynamics. Busulfan has been investigated widely for more than three decades leading to a large and precise handling of this agent with numerous studies on activity and pharmacokinetics and pharmacodynamics. In contrast, the behavior of treosulfan is still under investigation and not fully described. The complexity of treosulfan's metabolism and mechanism of action gives rise to the need of a deeper understanding of its pharmacological activity in a context of high-dose chemotherapy. Specifically, there is a great need to better understand its pharmacokinetics/pharmacodynamics relationship.

Rediscovering the Economics of Keynes in an Agent-Based Computational Setting

DEFF Research Database (Denmark)

Bruun, Charlotte

The aim of this paper is to use agent-based computational economics to explore the economic thinking of Keynes. Taking his starting point at the macroeconomic level, Keynes argued that economic systems are characterized by fundamental uncertainty - an uncertainty that makes rule-based behaviour...... and reliance on monetary magnitudes more optimal to the economic agent than profit- and utility optimazation in the traditional sense. Unfortunately more systematic studies of the properties of such a system was not possible at the time of Keynes. The system envisioned by Keynes holds a lot of properties...... in commen with what we today call complex dynamic systems, and today we may aply the method of agent-based computational economics to the ideas of Keynes. The presented agent-based Keynesian model demonstrate, as argued by Keynes, that the economy can selforganize without relying on price movement...

Formamidine sulfinic acid as reducing agent in technetium-99m rhenium sulfide labelling

Energy Technology Data Exchange (ETDEWEB)

Neves, M; Patricio, L [Laboratorio Nacional de Engenharia e Technologia Industrial, Sacavem (Portugal). Dept. de Radioisotopes; Ferronha, H [Laboratorio Nacional de Investigacao Veterinaria, Lisboa (Portugal)

1989-08-01

Labelling kinetic studies, radiochemical characterization and particle size evaluation of {sup 99m}Tc rhenium sulfide colloid using formamidine sulfinic acid as reducing agent are described. Comparison with the same colloid which makes use of Sn-sodium pyrophosphate complex as reducing agent showed higher labelling yields, simplification of labelling procedure and a longer shelf life when formamidine sulfinic acid was used. (author) 15 refs.; 7 figs.

Service orientation in holonic and multi-agent manufacturing

CERN Document Server

Thomas, André; Trentesaux, Damien

2015-01-01

This volume gathers the peer reviewed papers presented at the 4th edition of the International Workshop “Service Orientation in Holonic and Multi-agent Manufacturing – SOHOMA’14” organized and hosted on November 5-6, 2014 by the University of Lorraine, France in collaboration with the CIMR Research Centre of the University Politehnica of Bucharest and the TEMPO Laboratory of the University of Valenciennes and Hainaut-Cambrésis.   The book is structured in six parts, each one covering a specific research line which represents a trend in future manufacturing: (1) Holonic and Agent-based Industrial Automation Systems; (2) Service-oriented Management and Control of Manufacturing Systems; (3) Distributed Modelling for Safety and Security in Industrial Systems; (4) Complexity, Big Data and Virtualization in Computing-oriented Manufacturing; (5) Adaptive, Bio-inspired and Self-organizing Multi-Agent Systems for Manufacturing, and (6) Physical Internet Simulation, Modelling and Control.   There is a clear ...

An Agent-based Extensible Climate Control System for Sustainable Greenhouse Production

DEFF Research Database (Denmark)

Sørensen, Jan Corfixen; Jørgensen, Bo Nørregaard; Klein, Mark

2011-01-01

The slow adoption pace of new control strategies for sustainable greenhouse climate control by industrial growers is mainly due to the complexity of identifying and resolving potentially conflicting climate control requirements. In this paper, we present a multi-agent-based climate control system....... Negotiation is done using a novel multi-issue negotiation protocol that uses a generic algorithm to find an optimized solution within the search space. The Multi-Agent control system has been empirically evaluated in an ornamental floriculture research facility in Denmark. The evaluation showed...... that it is realistic to implement the climate control requirements as individual agents, thereby opening greenhouse climate control systems for integration of independently produced control strategies....

Synthesis And Characterization Of An Ion Imprinted Polymer For Cadmium Using Quinaldic Acid As Complexing Agent And Applying By Microwave

Directory of Open Access Journals (Sweden)

Asmawati

2015-01-01

Full Text Available Abstract A Cd2 Ion Imprinted Polymer Cd-IIP has been synthesized by copolymerizaton of cadmium ion quinaldic acid complexing agent 4-vynil pyridine monomer dimethyl sulfoxide solvent ethyleneglycoldimethacrylate EGDMA cross-linker and 22-azobis-isobutyronitrile AIBN initiator. Polymerization was conducted using a microwave at a temperature of 70 oC with heating times of 45 minutes. The template Cd2 was removed by leaching the template with ethanol and 4 M HCl washed by aquabidest and dried in an oven at the temperature of 60oC. The polymer particles imprinted and nonimprinted were characterized using fourir transform infrared FTIR spectroscopy scanning electron microscopy SEM and energy dispersive spectroscopy EDS. The result showed that using heating time 45 minutes at temperature 70 oC the particle morphology is viewed like as the large homogeneous. So the imprinted polymer had bands at 3483 cm-1 1726 cm-1 and 1155 cm-1 indicating the presence of OH CO and C-O respectively.

Synthesis and biodistribution of 99mTcN(PDTC)2 as a potential brain imaging agent

International Nuclear Information System (INIS)

JunBo Zhang; XueBin Wang; ChunJun Tian

2004-01-01

The preparation of the bis(N-propyl dithiocarbamato) nitrido technetium-99m complex 99m TcN(PDTC) 2 (PDTC: N-propyl dithiocarbamato) was carried out as a freeze-dried formulation, through a simple procedure involving the initial of 99m TcO 4 - with succinic dihydrazide in the presence of stannous chloride as reducing agent and propylenediamine tetraacetic acid (PDTA) as complexant, followed by the addition of the ligand sodium salt of N-propyl dithiocarbamate to afford the final product. The radiochemical purity of the complex was over 90%, as measured by thin layer chromatography. No decomposition of the complex at room temperature was observed over a period of 12 hours. Its partition coefficient indicated that it was a good lipophilic complex. Biodistribution in mice showed that the complex accumulated in the brain with high uptake. The brain uptake (ID%/g) was 5.07 and the brain/blood ratio 1.34 at 5-minute post-injection. This suggested a potential usefulness of the complex as a brain perfusion imaging agent. (author)

Novel mixed ligand technetium complexes as 5-HT1A receptor imaging agents

International Nuclear Information System (INIS)

Leon, A.; Rey, A.; Mallo, L.; Pirmettis, I.; Papadopoulos, M.; Leon, E.; Pagano, M.; Manta, E.; Incerti, M.; Raptopoulou, C.; Terzis, A.; Chiotellis, E.

2002-01-01

The synthesis, characterization and biological evaluation of two novel 3 + 1 mixed ligand 99m Tc-complexes, bearing the 1-(2-methoxyphenylpiperazine) moiety, a fragment of the true 5-HT 1A antagonist WAY 100635, is reported. Complexes at tracer level 99m TcO[(CH 3 CH 2 ) 2 NCH 2 CH 2 N(CH 2 CH 2 S) 2 ][o-CH 3 OC 6 H 4 N(CH 2 CH 2 ) 2 NCH 2 CH 2 S], 99m Tc-1, and 99m TcO[((CH 3 ) 2 CH) 2 NCH 2 CH 2 N(CH 2 CH 2 S) 2 ][o-CH 3 OC 6 H 4 N (CH 2 CH 2 ) 2 NCH 2 CH 2 S], 99m Tc-2, were prepared using 99m Tc-glucoheptonate as precursor. For structural characterization, the analogous oxorhenium complexes, Re-1 and Re-2, were prepared by ligand exchange reaction using ReOCl 3 (PPh 3 ) 2 as precursor, and characterized by elemental analysis and spectroscopic methods. Complex Re-1 was further characterized by crystallographic analysis. Labeling was performed with high yield (>85%) and radiochemical purity (>90%) using very low ligand concentration. The structure of 99m Tc complexes was established by comparative HPLC using the well-characterized oxorhenium analogues as references. In vitro binding assays demonstrated the affinity of these complexes for 5-HT 1A receptors (IC 50 : 67 and 45 nM for Re-1 and Re-2 respectively). Biological studies in mice showed the ability of 99m Tc-1 and 99m Tc-2 complexes to cross the intact blood-brain barrier (1.4 and 0.9% dose/g, respectively at 1 min post-inj.). The distribution of these complexes in various regions in rat brain is inhomogeneous. The highest ratio between areas reach and poor in 5-HT 1A receptors was calculated for complex Tc-1 at 60 min p.i. (hippocampus/cerebellum = 1.7).

Novel mixed ligand technetium complexes as 5-HT1A receptor imaging agents.

Science.gov (United States)

León, A; Rey, A; Mallo, L; Pirmettis, I; Papadopoulos, M; León, E; Pagano, M; Manta, E; Incerti, M; Raptopoulou, C; Terzis, A; Chiotellis, E

2002-02-01

The synthesis, characterization and biological evaluation of two novel 3 + 1 mixed ligand 99mTc-complexes, bearing the 1-(2-methoxyphenylpiperazine) moiety, a fragment of the true 5-HT1A antagonist WAY 100635, is reported. Complexes at tracer level 99mTcO[(CH3CH2)2NCH2CH2N(CH2CH2S)2][o-CH3OC6H4N(CH2CH2)2NCH2CH2S], 99mTc-1, and 99mTcO[((CH3)2CH)2NCH2CH2N(CH2CH2S)2][o-CH3OC6H4N (CH2CH2)2NCH2CH2S], 99mTc-2, were prepared using 99mTc-glucoheptonate as precursor. For structural characterization, the analogous oxorhenium complexes, Re-1 and Re-2, were prepared by ligand exchange reaction using ReOCl3(PPh3)2 as precursor, and characterized by elemental analysis and spectroscopic methods. Complex Re-1 was further characterized by crystallographic analysis. Labeling was performed with high yield (>85%) and radiochemical purity (>90%) using very low ligand concentration. The structure of 99mTc complexes was established by comparative HPLC using the well-characterized oxorhenium analogues as references. In vitro binding assays demonstrated the affinity of these complexes for 5-HT1A receptors (IC50 : 67 and 45 nM for Re-1 and Re-2 respectively). Biological studies in mice showed the ability of 99mTc-1 and 99mTc-2 complexes to cross the intact blood-brain barrier (1.4 and 0.9% dose/g, respectively at 1 min post-inj.). The distribution of these complexes in various regions in rat brain is inhomogeneous. The highest ratio between areas reach and poor in 5-HT1A receptors was calculated for complex Tc-1 at 60 min p.i. (hippocampus/cerebellum = 1.7).

AAZTA: an ideal chelating agent for the development of {sup 44}Sc PET imaging agents

Energy Technology Data Exchange (ETDEWEB)

Nagy, Gabor; Szikra, Dezso; Trencsenyi, Gyoergy [Scanomed Ltd., Debrecen (Hungary); University of Debrecen, Medical Imaging Clinic (Hungary); Fekete, Aniko [University of Debrecen, Medical Imaging Clinic (Hungary); Garai, Ildiko [Scanomed Ltd., Debrecen (Hungary); Giani, Arianna M.; Negri, Roberto [Dipartimento di Scienze del Farmaco, Universita del Piemonte Orientale, Novara (Italy); Masciocchi, Norberto [Dipartimento di Scienza e Alta Tecnologia e To.Sca.Lab, Universita degli Studi dell' Insubria, Como (Italy); Maiocchi, Alessandro; Uggeri, Fulvio [Bracco Imaging spa, Bracco Research Centre, Colleretto Giacosa (Italy); Toth, Imre [Department of Inorganic and Analytical Chemistry, University of Debrecen (Hungary); Aime, Silvio [Dipartimento di Biotecnologie Molecolari e Scienze della Salute, Centro di Imaging Molecolare e Preclinico, Universita degli Studi di Torino (Italy); Giovenzana, Giovanni B. [Dipartimento di Scienze del Farmaco, Universita del Piemonte Orientale, Novara (Italy); CAGE Chemicals srl, Novara (Italy); Baranyai, Zsolt [Bracco Imaging spa, Bracco Research Centre, Colleretto Giacosa (Italy); Department of Inorganic and Analytical Chemistry, University of Debrecen (Hungary)

2017-02-13

Unprecedented fast and efficient complexation of Sc{sup III} was demonstrated with the chelating agent AAZTA (AAZTA=1,4-bis(carboxymethyl)-6-[bis(carboxymethyl)] amino-6-methylperhydro-1,4-d iazepine) under mild experimental conditions. The robustness of the {sup 44}Sc(AAZTA){sup -} chelate and conjugated biomolecules thereof is further shown by in vivo PET imaging in healthy and tumor mice models. The new results pave the way towards development of efficient Sc-based radiopharmaceuticals using the AAZTA chelator. (copyright 2017 Wiley-VCH Verlag GmbH and Co. KGaA, Weinheim)

Development of 177Lu-phytate Complex for Radiosynovectomy

Directory of Open Access Journals (Sweden)

Hassan Yousefnia

2013-05-01

Full Text Available Objective(s: In this work a new possible agent for radiosynovectomy has been targeted for articular pain palliation. Materials and Methods: Lu-177 of 2.6-3 GBq/mg specific activity was obtained by irradiation of natural Lu2O3 sample with thermal neutron flux of 4 × 1013 n.cm-2.s-1. The product was converted into chloride form which was further used for labeling of 177Lu-phytate complex and checked using ITLC (MeOH: H2O: acetic acid, 4: 4: 2, as mobile phase. The complex stability and viscosity were checked in the final solution up to seven days. The prepared complex solution (100 µCi/100 µl was injected intra-articularly to male rat knee joint. Leakage of radioactivity from injection site and its distribution in organs were investigated up to seven days. Results: The complex was successfully prepared with high radiochemical purity (>99.9 %. Approximately, the whole injected dose has remained in injection site seven days after injection. Conclusion: The complex was proved to be a feasible agent for cavital radiotherapy in oncology and rheumatology

Contrast agents for tumor diagnosis in magnetic resonance imaging

Energy Technology Data Exchange (ETDEWEB)

Goto, Rensuke; Doi, Hisayoshi; Okada, Shoji [University of Shizuoka (Japan). School of Pharmaceutical Science; Yano, Masayuki; Katano, Susumu; Nakajima, Nobuaki

1992-01-01

In order to develop contrast agents for tumor diagnosis in magnetic resonance imaging (MRI), we investigated the effects of several gadolinium complexes on T{sub 1} relaxation time of proton in some tissues of Ehrlich solid tumor-bearing mice. L-Aspartic acid, L-glutamic acid, DL-homocysteine, L-glutamyl-glutamic acid, glutathione, sperimidine and ethylenediaminetetrakis (methylenephosphate) (EDTMP) were used as ligands for Gd{sup 3+}. Since each Gd-complex could not be purified except Gd-EDTMP, the mixture of GdCl{sub 3} and a ligand was administered intravenously. Among the compounds tested, the mixture of aspartic acid, glutathione or spermidine with GdCl{sub 3} showed almost the same or above reduction of T{sub 1} relaxation times in the tumor tissue compared with Gd-diethylenetriamine pentaacetic acid (Gd-DTPA) which is used clinically. Furthermore, the contrast-enhancing effect of the three mixtures in the tumor was observed by in vivo T{sub 1}-weighted magnetic resonance imaging. The in vivo tissue distribution using radioactive {sup 153}Gd{sup 3+} showed that these mixtures mentioned above were also taken up more highly in the tumor than {sup 153}GdCl{sub 3} itself and {sup 153}Gd-DTPA, suggesting the formation of Gd-complexes. However, the overall tissue distribution of the mixtures was similar to that of {sup 153}GdCl{sub 3} because the Gd-complexes were not purified. Gd-EDTMP exhibited the almost same effects with Gd-DTPA as a contrast agent. (author).

Coordinated Control of Multi-Agent Systems in Rapidly Varying Environments, Phase II

Data.gov (United States)

National Aeronautics and Space Administration — The main objective of this Phase II STTR project is to develop advanced control algorithms that enable multiple autonomous agents to perform complex tasks in rapidly...

INTERPOLYELECTROLYTE COMPLEXES AS PROSPECTIVE CARRIERS FOR CONTROLLED DRUG DELIVERY

OpenAIRE

Kaur Jasmeet; Harikumar S.L.; Kaur Amanpreet

2012-01-01

In the current scenario, polymers as carriers have revolutionized the drug delivery system. A more successful approach, to exploit the different properties of polymers in a solitary system is the complexation of polymers to form polyelectrolyte complexes. These complexes circumvent the use of chemical crosslinking agents, thereby reducing the risk of toxicity. The complex formed is generally applied in different dosage forms for the formulation of stable aggregated macromolecules. There are t...

Twenty years of principal-agent research in EU politics: how to cope with complexity?

NARCIS (Netherlands)

Delreux, Tom; Adriaensen, J.

2017-01-01

In the 20 years after its introduction, the principal-agent model has seen increasing use to study political processes in virtually all policy domains in which the EU is active. Relaxing the strict assumptions that guided the original economic applications has greatly widened the scope for potential

Zinc removal from wastewater by complexation-microfiltration process

Directory of Open Access Journals (Sweden)

Trivunac Katarina

2012-01-01

Full Text Available As a result of its wide industrial applications, zinc has become an important contaminant in aquatic environment since it is a toxic heavy metal and some of its compounds such as zinc arsenate and zinc cyanide, may be extremely hazardous. Therefore, there is a growing need for developing simple methods capable of separating and recovering trace zinc from environmental waters. Nowadays, the ultra and microfiltration method for trace metals removal from waters by the addition of water-soluble polymers into the aqueous solutions has become a significant research area. The choice of watersoluble macroligands remains important for developing this technology. Sodium carboxymethyl cellulose (Na-CMC was selected as complexing agent. The microfiltration experiments were carried out in stirred dead-end cell. To separate formed polymer-metal complex Versapor membranes were used. The concentration of heavy metal ions after microfiltration in aqueous solution was determined using atomic absorption spectroscopy (AAS. Effects of amount of complexing agent, pH value, type of anion, ionic strength and operating pressure on the flux (J and rejection coefficient (R were investigated. Experimental results indicate a considerable influence of the pH, ionic strength and type of anion on the rejection coefficient, while effect of amount of complexing agent is relatively insignificant. The Na-CMC used in the research proved to be very effective, which may be supported by the high rejection coefficients obtained (99%.

Transient phytoextraction agents: establishing criteria for the use of chelants in phytoextraction of recalcitrant metals.

Science.gov (United States)

Parra, R; Ulery, A L; Elless, M P; Blaylock, M J

2008-01-01

The phytoremediation of recalcitrant metals such as lead and uranium rely on soil amendments to enhance metal availability within the rhizosphere. Because these amendments may persist in soils, agents that not only biodegrade rapidly but also are effective in triggering metal uptake in plants are needed for metals phytoextraction to be considered as an accepted practice. In this study, several biodegradable organic acids and chelating agents were assessed to determine if these amendments can be used in an effective manner, and if their activity and use is consistent with a proposed class of soil amendments for phytoextraction, here termed transient phytoextraction agents (TPAs). A TPA is proposed as an agent that would exhibit both effectiveness in triggering plant accumulation of the targeted metal while minimizing the risk of migration through rapid degradation or inactivation of the soluble complex. Eleven candidate TPAs (acetic acid, ascorbic acid, citric acid, malic acid, oxalic acid, succinic acid, ethylenediaminedisuccinic acid, dicarboxymethylglutamic acid, nitrilotriacetic acid, BayPure CX 100, and the siderophore desferrioxamine B) were tested in batch studies to evaluate their complexation behavior using contaminated soils, with uranium and lead as the target metals. A growth chamber study was then conducted with Brassica juncea (Indian mustard), Helianthus annuus (sunflower), and Festuca arundinacea (tall fescue) grown in a lead-contaminated soil that was treated with the candidate TPAs to assess phytoextraction effectiveness. For the soils tested, citric acid, oxalic acid, and succinic acid were found to be effective complexing agents for uranium phytoextraction, whereas Baypure CX 100 and citric acid exhibited effectiveness for lead phytoextraction.

Design of New-Generation Usable Forms of Topical Haemostatic Agents Containing Chitosan

Directory of Open Access Journals (Sweden)

Dorota Zielińska

2017-12-01

Full Text Available Designing usable forms of topical haemostatic agents is the most important activity during the design process, resulting in strengthened functional properties of the final medical devices. This study aimed to propose indications for a research programme based on risk management supporting the development of two usable forms of a topical haemostatic agent: chitosan/alginate lyophilized foam and chitosan/alginate impregnated gauze. Both of the usable forms of the topical haemostatic agent, being the main part of the modified combat gauze, were fabricated using the chitosan/alginate complex. Risk analysis is helpful in developing an appropriate research programme, significantly reducing the risk to an acceptable level.

Effective Team Support: From Task and Cognitive Modeling to Software Agents for Time-Critical Complex Work Environments

Science.gov (United States)

Remington, Roger W. (Technical Monitor); John, Bonnie E.; Sycara, Katia

2005-01-01

The purpose of this research contract was to perform multidisciplinary research between CMU psychologists, computer scientists and NASA researchers to design a next generation collaborative system to support a team of human experts and intelligent agents. To achieve robust performance enhancement of such a system, we had proposed to perform task and cognitive modeling to thoroughly understand the impact technology makes on the organization and on key individual personnel. Guided by cognitively-inspired requirements, we would then develop software agents that support the human team in decision making, information filtering, information distribution and integration to enhance team situational awareness. During the period covered by this final report, we made substantial progress in completing a system for empirical data collection, cognitive modeling, and the building of software agents to support a team's tasks, and in running experiments for the collection of baseline data.

Incorporating BDI Agents into Human-Agent Decision Making Research

Science.gov (United States)

Kamphorst, Bart; van Wissen, Arlette; Dignum, Virginia

Artificial agents, people, institutes and societies all have the ability to make decisions. Decision making as a research area therefore involves a broad spectrum of sciences, ranging from Artificial Intelligence to economics to psychology. The Colored Trails (CT) framework is designed to aid researchers in all fields in examining decision making processes. It is developed both to study interaction between multiple actors (humans or software agents) in a dynamic environment, and to study and model the decision making of these actors. However, agents in the current implementation of CT lack the explanatory power to help understand the reasoning processes involved in decision making. The BDI paradigm that has been proposed in the agent research area to describe rational agents, enables the specification of agents that reason in abstract concepts such as beliefs, goals, plans and events. In this paper, we present CTAPL: an extension to CT that allows BDI software agents that are written in the practical agent programming language 2APL to reason about and interact with a CT environment.

Complexity a very short introduction

CERN Document Server

Holland, John H

2014-01-01

The importance of complexity is well-captured by Hawking's comment: "Complexity is the science of the 21st century". From the movement of flocks of birds to the Internet, environmental sustainability, and market regulation, the study and understanding of complex non-linear systems has become highly influential over the last 30 years. In this Very Short Introduction, one of the leading figures in the field, John Holland, introduces the key elements and conceptual framework of complexity. From complex physical systems such as fluid flow and the difficulties of predicting weather, to complex adaptive systems such as the highly diverse and interdependent ecosystems of rainforests, he combines simple, well-known examples - Adam Smith's pin factory, Darwin's comet orchid, and Simon's 'watchmaker' - with an account of the approaches, involving agents and urn models, taken by complexity theory. ABOUT THE SERIES: The Very Short Introductions series from Oxford University Press contains hundreds of titles in almost eve...

An attempt to evaluate the effect of vitamin K3 using as an enhancer of anticancer agents.

Science.gov (United States)

Matzno, Sumio; Yamaguchi, Yuka; Akiyoshi, Takeshi; Nakabayashi, Toshikatsu; Matsuyama, Kenji

2008-06-01

The possibility of vitamin K3 (VK3) as an anticancer agent was assessed. VK3 dose-dependently diminished the cell viability (measured as esterase activity) with IC50 of 13.7 microM and Hill coefficient of 3.1 in Hep G2 cells. It also decreased the population of S phase and arrested cell cycle in the G2/M phase in a dose-dependent manner. G2/M arrest was regulated by the increment of cyclin A/cdk1 and cyclin A/cdk2 complex, and contrasting cyclin B/cdk1 complex decrease. Finally, combined application demonstrated that VK3 significantly enhanced the cytotoxicity of etoposide, a G2 phase-dependent anticancer agent, whereas it reduced the cytotoxic activity of irinotecan, a S phase-dependent agent. These findings suggest that VK3 induces G2/M arrest by inhibition of cyclin B/cdk1 complex formation, and is thus useful as an enhancer of G2 phase-dependent drugs in hepatic cancer chemotherapy.

Logics for Intelligent Agents and Multi-Agent Systems

NARCIS (Netherlands)

Meyer, John-Jules Charles

2014-01-01

This chapter presents the history of the application of logic in a quite popular paradigm in contemporary computer science and artificial intelligence, viz. the area of intelligent agents and multi-agent systems. In particular we discuss the logics that have been used to specify single agents, the

CATS-based Air Traffic Controller Agents

Science.gov (United States)

Callantine, Todd J.

2002-01-01

This report describes intelligent agents that function as air traffic controllers. Each agent controls traffic in a single sector in real time; agents controlling traffic in adjoining sectors can coordinate to manage an arrival flow across a given meter fix. The purpose of this research is threefold. First, it seeks to study the design of agents for controlling complex systems. In particular, it investigates agent planning and reactive control functionality in a dynamic environment in which a variety perceptual and decision making skills play a central role. It examines how heuristic rules can be applied to model planning and decision making skills, rather than attempting to apply optimization methods. Thus, the research attempts to develop intelligent agents that provide an approximation of human air traffic controller behavior that, while not based on an explicit cognitive model, does produce task performance consistent with the way human air traffic controllers operate. Second, this research sought to extend previous research on using the Crew Activity Tracking System (CATS) as the basis for intelligent agents. The agents use a high-level model of air traffic controller activities to structure the control task. To execute an activity in the CATS model, according to the current task context, the agents reference a 'skill library' and 'control rules' that in turn execute the pattern recognition, planning, and decision-making required to perform the activity. Applying the skills enables the agents to modify their representation of the current control situation (i.e., the 'flick' or 'picture'). The updated representation supports the next activity in a cycle of action that, taken as a whole, simulates air traffic controller behavior. A third, practical motivation for this research is to use intelligent agents to support evaluation of new air traffic control (ATC) methods to support new Air Traffic Management (ATM) concepts. Current approaches that use large, human

Biological Agents

Science.gov (United States)

... E-Tools Safety and Health Topics / Biological Agents Biological Agents This page requires that javascript be enabled ... 202) 693-2300 if additional assistance is required. Biological Agents Menu Overview In Focus: Ebola Frederick A. ...

OWL model of multi-agent Smart-system of distance learning for people with vision disabilities

Directory of Open Access Journals (Sweden)

Galina A. Samigulina

2017-01-01

Full Text Available The aim of the study is to develop an ontological model of multiagent smart-system of distance learning for visually impaired people based on Java Agent Development Framework for obtaining high-quality engineering education in laboratories of join use on modern equipment.Materials and methods of research. In developing multi-agent smart-system of distance learning, using various agents based on cognitive, ontological, statistical and intellectual methods is important. It is more convenient to implement this task in the form of software using multi-agent approach and Java Agent Development Framework. The main advantages of the platform are stability of operation, clear interface, simplicity of creating agents and extensive user database. In multi-agent systems, the solution is obtained automatically as result of interaction of many independent, purposeful agents. Each agent can perform certain tasks and pursue specified goals. Intellectual multi-agent systems and practical applications in distance learning based on them are considered.Results. The structural diagram of functioning of smart system distance learning for visually impaired people using various agents based on the system approach and the multi-agent platform Java Agent Development Framework is developed. The complex approach of distance learning of visually impaired people for obtaining highquality engineering education in laboratories of joint use on modern equipment is offered.The ontological model of multi-agent smart-system with a detailed description of the functions of following agents is created: personal, manager, ontological, cognitive, statistical, intellectual, shared laboratory agent, health agent, assistant to the agent and state agent. These agents execute their individual functions and provide a quality environment for learning.Conclusion. Thus, the proposed smart-system of distance learning for visually impaired people can significantly improve effectiveness and

Interacting agents through a web-based health serviceflow management system

NARCIS (Netherlands)

Leonardi, G.; Panzarasa, S.; Quaglini, S.; Stefanelli, M.; Aalst, van der W.M.P.

2007-01-01

The management of chronic and out-patients is a complex process which requires the cooperation of different agents belonging to several organizational units. Patients have to move to different locations to access the necessary services and to communicate their health status data. From their point of

Fuzzy Cognitive and Social Negotiation Agent Strategy for Computational Collective Intelligence

Science.gov (United States)

Chohra, Amine; Madani, Kurosh; Kanzari, Dalel

Finding the adequate (win-win solutions for both parties) negotiation strategy with incomplete information for autonomous agents, even in one-to-one negotiation, is a complex problem. Elsewhere, negotiation behaviors, in which the characters such as conciliatory or aggressive define a 'psychological' aspect of the negotiator personality, play an important role. The aim of this paper is to develop a fuzzy cognitive and social negotiation strategy for autonomous agents with incomplete information, where the characters conciliatory, neutral, or aggressive, are suggested to be integrated in negotiation behaviors (inspired from research works aiming to analyze human behavior and those on social negotiation psychology). For this purpose, first, one-to-one bargaining process, in which a buyer agent and a seller agent negotiate over single issue (price), is developed for a time-dependent strategy (based on time-dependent behaviors of Faratin et al.) and for a fuzzy cognitive and social strategy. Second, experimental environments and measures, allowing a set of experiments, carried out for different negotiation deadlines of buyer and seller agents, are detailed. Third, experimental results for both time-dependent and fuzzy cognitive and social strategies are presented, analyzed, and compared for different deadlines of agents. The suggested fuzzy cognitive and social strategy allows agents to improve the negotiation process, with regard to the time-dependent one, in terms of agent utilities, round number to reach an agreement, and percentage of agreements.

Fast Conflict Resolution Based on Reinforcement Learning in Multi-agent System

Institute of Scientific and Technical Information of China (English)

PIAOSonghao; HONGBingrong; CHUHaitao

2004-01-01

In multi-agent system where each agen thas a different goal (even the team of agents has the same goal), agents must be able to resolve conflicts arising in the process of achieving their goal. Many researchers presented methods for conflict resolution, e.g., Reinforcement learning (RL), but the conventional RL requires a large computation cost because every agent must learn, at the same time the overlap of actions selected by each agent results in local conflict. Therefore in this paper, we propose a novel method to solve these problems. In order to deal with the conflict within the multi-agent system, the concept of potential field function based Action selection priority level (ASPL) is brought forward. In this method, all kinds of environment factor that may have influence on the priority are effectively computed with the potential field function. So the priority to access the local resource can be decided rapidly. By avoiding the complex coordination mechanism used in general multi-agent system, the conflict in multi-agent system is settled more efficiently. Our system consists of RL with ASPL module and generalized rules module. Using ASPL, RL module chooses a proper cooperative behavior, and generalized rule module can accelerate the learning process. By applying the proposed method to Robot Soccer, the learning process can be accelerated. The results of simulation and real experiments indicate the effectiveness of the method.

Mechanistic origin of dragon-kings in a population of competing agents

Science.gov (United States)

Johnson, N.; Tivnan, B.

2012-05-01

We analyze the mechanistic origins of the extreme behaviors that arise in an idealized model of a population of competing agents, such as traders in a market. These extreme behaviors exhibit the defining characteristics of `dragon-kings'. Our model comprises heterogeneous agents who repeatedly compete for some limited resource, making binary choices based on the strategies that they have in their possession. It generalizes the well-known Minority Game by allowing agents whose strategies have not made accurate recent predictions, to step out of the competition until their strategies improve. This generates a complex dynamical interplay between the number V of active agents (mimicking market volume) and the imbalance D between the decisions made (mimicking excess demand). The wide spectrum of extreme behaviors which emerge, helps to explain why no unique relationship has been identified between the price and volume during real market crashes and rallies.

Grounding language in action and perception: from cognitive agents to humanoid robots.

Science.gov (United States)

Cangelosi, Angelo

2010-06-01

In this review we concentrate on a grounded approach to the modeling of cognition through the methodologies of cognitive agents and developmental robotics. This work will focus on the modeling of the evolutionary and developmental acquisition of linguistic capabilities based on the principles of symbol grounding. We review cognitive agent and developmental robotics models of the grounding of language to demonstrate their consistency with the empirical and theoretical evidence on language grounding and embodiment, and to reveal the benefits of such an approach in the design of linguistic capabilities in cognitive robotic agents. In particular, three different models will be discussed, where the complexity of the agent's sensorimotor and cognitive system gradually increases: from a multi-agent simulation of language evolution, to a simulated robotic agent model for symbol grounding transfer, to a model of language comprehension in the humanoid robot iCub. The review also discusses the benefits of the use of humanoid robotic platform, and specifically of the open source iCub platform, for the study of embodied cognition. Copyright 2010 Elsevier B.V. All rights reserved.

Development of Semantic Web-Enabled BDI Multi-Agent Systems Using SEA_ML: An Electronic Bartering Case Study

NARCIS (Netherlands)

Challenger, M.; Tezel, Baris Tekin; Alaca, Ömer Faruk; Tekinerdogan, B.; Kardas, Geylani

2018-01-01

In agent-oriented software engineering (AOSE), the application of model-driven development (MDD) and the use of domain-specific modeling languages (DSMLs) for Multi-Agent System (MAS) development are quite popular since the implementation of MAS is naturally complex, error-prone, and costly due to

The structure of intelligent agent projecting and the possibilities of its execution

Directory of Open Access Journals (Sweden)

Yefremov M.F.

2017-04-01

Full Text Available Most of today’s information systems are not designed for independent decision making, behavior of such systems should be incorporated at the design stage. Entering the conditions that are not included by system developers, lead to a crash. The exponential growth of computing power of modern processors leads to an increase in range of tasks that can be automated, and an increase in their complexity. Partially testing helps to solve the problem, but it has a drawback, precisely the behavior of the system is usually tested in conditions which are already taken into account at the design stage. One approach to address this problem is the agent-oriented programming and the use of multi-agent systems. The aim of the work is to highlight contemporary approaches: a definition of agent concepts, applications of multi-agent systems, mathematical model agent, modern methods of design and implementation of intelligent agents, also covered approaches to the definition of the concept of an intelligent agent, the application of intelligent agents and multi-agent systems, and methods theoretically agent and describe its implementation. The basis of these methods of abstract description of the intelligent agent is the works of M.Wooldridge and N.Jennings. We propose several methods to describe such behaviors of intelligent agent as self-learning, goal setting and forecasting, and planning. Therefore we cover the concept of «intent» and widespread mental (beliefs-desires-intentions BDI architecture of intelligent agent, as well as the proposed methods of their description in the framework of the developed formalism.

An agent-based method for simulating porous fluid-saturated structures with indistinguishable components

Science.gov (United States)

Kashani, Jamal; Pettet, Graeme John; Gu, YuanTong; Zhang, Lihai; Oloyede, Adekunle

2017-10-01

Single-phase porous materials contain multiple components that intermingle up to the ultramicroscopic level. Although the structures of the porous materials have been simulated with agent-based methods, the results of the available methods continue to provide patterns of distinguishable solid and fluid agents which do not represent materials with indistinguishable phases. This paper introduces a new agent (hybrid agent) and category of rules (intra-agent rule) that can be used to create emergent structures that would more accurately represent single-phase structures and materials. The novel hybrid agent carries the characteristics of system's elements and it is capable of changing within itself, while also responding to its neighbours as they also change. As an example, the hybrid agent under one-dimensional cellular automata formalism in a two-dimensional domain is used to generate patterns that demonstrate the striking morphological and characteristic similarities with the porous saturated single-phase structures where each agent of the ;structure; carries semi-permeability property and consists of both fluid and solid in space and at all times. We conclude that the ability of the hybrid agent to change locally provides an enhanced protocol to simulate complex porous structures such as biological tissues which could facilitate models for agent-based techniques and numerical methods.

Agent Behavior-Based Simulation Study on Mass Collaborative Product Development Process

Directory of Open Access Journals (Sweden)

Shuo Zhang

2015-01-01

Full Text Available Mass collaborative product development (MCPD benefits people by high innovation products with lower cost and shorter lead time due to quick development of group innovation, Internet-based customization, and prototype manufacturing. Simulation is an effective way to study the evolution process and therefore to guarantee the success of MCPD. In this paper, an agent behavior-based simulation approach of MCPD is developed, which models the MCPD process as the interactive process of design agents and the environment objects based on Complex Adaptive System (CAS theory. Next, the structure model of design agent is proposed, and the modification and collaboration behaviors are described. Third, the agent behavior-based simulation flow of MCPD is designed. At last, simulation experiments are carried out based on an engineering case of mobile phone design. The experiment results show the following: (1 the community scale has significant influence on MCPD process; (2 the simulation process can explicitly represent the modification and collaboration behaviors of design agents; (3 the community evolution process can be observed and analyzed dynamically based on simulation data.

Information-Theoretic Approaches for Evaluating Complex Adaptive Social Simulation Systems

Energy Technology Data Exchange (ETDEWEB)

Omitaomu, Olufemi A [ORNL; Ganguly, Auroop R [ORNL; Jiao, Yu [ORNL

2009-01-01

In this paper, we propose information-theoretic approaches for comparing and evaluating complex agent-based models. In information theoretic terms, entropy and mutual information are two measures of system complexity. We used entropy as a measure of the regularity of the number of agents in a social class; and mutual information as a measure of information shared by two social classes. Using our approaches, we compared two analogous agent-based (AB) models developed for regional-scale social-simulation system. The first AB model, called ABM-1, is a complex AB built with 10,000 agents on a desktop environment and used aggregate data; the second AB model, ABM-2, was built with 31 million agents on a highperformance computing framework located at Oak Ridge National Laboratory, and fine-resolution data from the LandScan Global Population Database. The initializations were slightly different, with ABM-1 using samples from a probability distribution and ABM-2 using polling data from Gallop for a deterministic initialization. The geographical and temporal domain was present-day Afghanistan, and the end result was the number of agents with one of three behavioral modes (proinsurgent, neutral, and pro-government) corresponding to the population mindshare. The theories embedded in each model were identical, and the test simulations focused on a test of three leadership theories - legitimacy, coercion, and representative, and two social mobilization theories - social influence and repression. The theories are tied together using the Cobb-Douglas utility function. Based on our results, the hypothesis that performance measures can be developed to compare and contrast AB models appears to be supported. Furthermore, we observed significant bias in the two models. Even so, further tests and investigations are required not only with a wider class of theories and AB models, but also with additional observed or simulated data and more comprehensive performance measures.

The human milk protein-lipid complex HAMLET sensitizes bacterial pathogens to traditional antimicrobial agents.

Science.gov (United States)

Marks, Laura R; Clementi, Emily A; Hakansson, Anders P

2012-01-01

The fight against antibiotic resistance is one of the most significant challenges to public health of our time. The inevitable development of resistance following the introduction of novel antibiotics has led to an urgent need for the development of new antibacterial drugs with new mechanisms of action that are not susceptible to existing resistance mechanisms. One such compound is HAMLET, a natural complex from human milk that kills Streptococcus pneumoniae (the pneumococcus) using a mechanism different from common antibiotics and is immune to resistance-development. In this study we show that sublethal concentrations of HAMLET potentiate the effect of common antibiotics (penicillins, macrolides, and aminoglycosides) against pneumococci. Using MIC assays and short-time killing assays we dramatically reduced the concentrations of antibiotics needed to kill pneumococci, especially for antibiotic-resistant strains that in the presence of HAMLET fell into the clinically sensitive range. Using a biofilm model in vitro and nasopharyngeal colonization in vivo, a combination of HAMLET and antibiotics completely eradicated both biofilms and colonization in mice of both antibiotic-sensitive and resistant strains, something each agent alone was unable to do. HAMLET-potentiation of antibiotics was partially due to increased accessibility of antibiotics to the bacteria, but relied more on calcium import and kinase activation, the same activation pathway HAMLET uses when killing pneumococci by itself. Finally, the sensitizing effect was not confined to species sensitive to HAMLET. The HAMLET-resistant respiratory species Acinetobacter baumanii and Moraxella catarrhalis were all sensitized to various classes of antibiotics in the presence of HAMLET, activating the same mechanism as in pneumococci. Combined these results suggest the presence of a conserved HAMLET-activated pathway that circumvents antibiotic resistance in bacteria. The ability to activate this pathway may extend

Decision theory with resource-bounded agents.

Science.gov (United States)

Halpern, Joseph Y; Pass, Rafael; Seeman, Lior

2014-04-01

There have been two major lines of research aimed at capturing resource-bounded players in game theory. The first, initiated by Rubinstein (), charges an agent for doing costly computation; the second, initiated by Neyman (), does not charge for computation, but limits the computation that agents can do, typically by modeling agents as finite automata. We review recent work on applying both approaches in the context of decision theory. For the first approach, we take the objects of choice in a decision problem to be Turing machines, and charge players for the "complexity" of the Turing machine chosen (e.g., its running time). This approach can be used to explain well-known phenomena like first-impression-matters biases (i.e., people tend to put more weight on evidence they hear early on) and belief polarization (two people with different prior beliefs, hearing the same evidence, can end up with diametrically opposed conclusions) as the outcomes of quite rational decisions. For the second approach, we model people as finite automata, and provide a simple algorithm that, on a problem that captures a number of settings of interest, provably performs optimally as the number of states in the automaton increases. Copyright © 2014 Cognitive Science Society, Inc.

Evolutionary and adaptive learning in complex markets: a brief summary

Science.gov (United States)

Hommes, Cars H.

2007-06-01

We briefly review some work on expectations and learning in complex markets, using the familiar demand-supply cobweb model. We discuss and combine two different approaches on learning. According to the adaptive learning approach, agents behave as econometricians using time series observations to form expectations, and update the parameters as more observations become available. This approach has become popular in macro. The second approach has an evolutionary flavor and is sometimes referred to as reinforcement learning. Agents employ different forecasting strategies and evaluate these strategies based upon a fitness measure, e.g. past realized profits. In this framework, boundedly rational agents switch between different, but fixed behavioral rules. This approach has become popular in finance. We combine evolutionary and adaptive learning to model complex markets and discuss whether this theory can match empirical facts and forecasting behavior in laboratory experiments with human subjects.

Gadolinium DTPA-monoamide complexes incorporated into mixed micelles as possible MRI contrast agents

OpenAIRE

Parac-Vogt, Tatjana; Kimpe, Kristof; Laurent, Sophie; Pierart, Corinne; Vander Elst, Luce; Muller, Robert N.; Binnemans, Koen

2004-01-01

Four monoamide derivatives of Gd-DTPA with alkyl chains consisting of 12, 14, 16, or 18 carbon atoms were synthesized. The gadolinium(III) complexes with chain lengths of 14, 16 or 18 carbon atoms were efficiently incorporated into mixed micelles whereas the complex with a chain length of 12 carbon atoms was not incorporated into a micellar structure. The size distribution of the micelles was measured by photon correlation spectroscopy. The mean sizes of the micelles for all the complexes lay...

Event-triggered hybrid control based on multi-Agent systems for Microgrids

DEFF Research Database (Denmark)

Dou, Chun-xia; Liu, Bin; Guerrero, Josep M.

2014-01-01

This paper is focused on a multi-agent system based event-triggered hybrid control for intelligently restructuring the operating mode of an microgrid (MG) to ensure the energy supply with high security, stability and cost effectiveness. Due to the microgrid is composed of different types...... of distributed energy resources, thus it is typical hybrid dynamic network. Considering the complex hybrid behaviors, a hierarchical decentralized coordinated control scheme is firstly constructed based on multi-agent sys-tem, then, the hybrid model of the microgrid is built by using differential hybrid Petri...

Easing the adoption of agent-based modelling (ABM) in tourism research

NARCIS (Netherlands)

Johnson, Peter; Nicholls, Sarah; Student, Jillian; Amelung, Bas; Baggio, Rodolfo; Balbi, Stefano; Boavida-Portugal, Ines; Jong, de Eline; Hofstede, G.J.; Lamers, M.A.J.; Pons, Marc; Steiger, Robert

2017-01-01

Agent-based modelling (ABM) is an emerging approach in tourism research. Despite the natural fit between theories of tourism as a complex, interconnected system, and the generative approach supported in ABM, there has been only limited integration within mainstream tourism research. This research

CASCADE: An Agent Based Framework For Modeling The Dynamics Of Smart Electricity Systems

OpenAIRE

Rylatt, R. M.; Gammon, Rupert; Boait, Peter John; Varga, L.; Allen, P.; Savill, M.; Snape, J. Richard; Lemon, Mark; Ardestani, B. M.; Pakka, V. H.; Fletcher, G.; Smith, S.; Fan, D.; Strathern, M.

2013-01-01

Collaborative project with Cranfield University The Complex Adaptive Systems, Cognitive Agents and Distributed Energy (CASCADE) project is developing a framework based on Agent Based Modelling (ABM). The CASCADE Framework can be used both to gain policy and industry relevant insights into the smart grid concept itself and as a platform to design and test distributed ICT solutions for smart grid based business entities. ABM is used to capture the behaviors of diff erent socia...

Agent Based Individual Traffic guidance

DEFF Research Database (Denmark)

Wanscher, Jørgen Bundgaard

2004-01-01

When working with traffic planning or guidance it is common practice to view the vehicles as a combined mass. >From this models are employed to specify the vehicle supply and demand for each region. As the models are complex and the calculations are equally demanding the regions and the detail...... of the road network is aggregated. As a result the calculations reveal only what the mass of vehicles are doing and not what a single vehicle is doing. This is the crucial difference to ABIT (Agent Based Individual Trafficguidance). ABIT is based on the fact that information on the destination of each vehicle...

Agent-based modelling in synthetic biology.

Science.gov (United States)

Gorochowski, Thomas E

2016-11-30

Biological systems exhibit complex behaviours that emerge at many different levels of organization. These span the regulation of gene expression within single cells to the use of quorum sensing to co-ordinate the action of entire bacterial colonies. Synthetic biology aims to make the engineering of biology easier, offering an opportunity to control natural systems and develop new synthetic systems with useful prescribed behaviours. However, in many cases, it is not understood how individual cells should be programmed to ensure the emergence of a required collective behaviour. Agent-based modelling aims to tackle this problem, offering a framework in which to simulate such systems and explore cellular design rules. In this article, I review the use of agent-based models in synthetic biology, outline the available computational tools, and provide details on recently engineered biological systems that are amenable to this approach. I further highlight the challenges facing this methodology and some of the potential future directions. © 2016 The Author(s).

Simulation of Weak Signals of Nanotechnology Innovation in Complex System

Directory of Open Access Journals (Sweden)

Sun Hi Yoo

2018-02-01

Full Text Available It is especially indispensable for new businesses or industries to predict the innovation of new technologies. This requires an understanding of how the complex process of innovation, which is accomplished through more efficient products, processes, services, technologies, or ideas, is adopted and diffused in the market, government, and society. Furthermore, detecting “weak signals” (signs of change in science and technology (S&T is also important to foretell events associated with innovations in technology. Thus, we explore the dynamic behavior of weak signals of a specific technological innovation using the agent-based simulating tool NetLogo. This study provides a deeper understanding of the early stages of complex technology innovation, and the models are capable of analyzing initial complex interaction structures between components of technologies and between agents engaged in collective invention.

A Culture-Sensitive Agent in Kirman's Ant Model

Science.gov (United States)

Chen, Shu-Heng; Liou, Wen-Ching; Chen, Ting-Yu

The global financial crisis brought a serious collapse involving a "systemic" meltdown. Internet technology and globalization have increased the chances for interaction between countries and people. The global economy has become more complex than ever before. Mark Buchanan [12] indicated that agent-based computer models will prevent another financial crisis and has been particularly influential in contributing insights. There are two reasons why culture-sensitive agent on the financial market has become so important. Therefore, the aim of this article is to establish a culture-sensitive agent and forecast the process of change regarding herding behavior in the financial market. We based our study on the Kirman's Ant Model[4,5] and Hofstede's Natational Culture[11] to establish our culture-sensitive agent based model. Kirman's Ant Model is quite famous and describes financial market herding behavior from the expectations of the future of financial investors. Hofstede's cultural consequence used the staff of IBM in 72 different countries to understand the cultural difference. As a result, this paper focuses on one of the five dimensions of culture from Hofstede: individualism versus collectivism and creates a culture-sensitive agent and predicts the process of change regarding herding behavior in the financial market. To conclude, this study will be of importance in explaining the herding behavior with cultural factors, as well as in providing researchers with a clearer understanding of how herding beliefs of people about different cultures relate to their finance market strategies.

Agent-based modelling of consumer energy choices

Science.gov (United States)

Rai, Varun; Henry, Adam Douglas

2016-06-01

Strategies to mitigate global climate change should be grounded in a rigorous understanding of energy systems, particularly the factors that drive energy demand. Agent-based modelling (ABM) is a powerful tool for representing the complexities of energy demand, such as social interactions and spatial constraints. Unlike other approaches for modelling energy demand, ABM is not limited to studying perfectly rational agents or to abstracting micro details into system-level equations. Instead, ABM provides the ability to represent behaviours of energy consumers -- such as individual households -- using a range of theories, and to examine how the interaction of heterogeneous agents at the micro-level produces macro outcomes of importance to the global climate, such as the adoption of low-carbon behaviours and technologies over space and time. We provide an overview of ABM work in the area of consumer energy choices, with a focus on identifying specific ways in which ABM can improve understanding of both fundamental scientific and applied aspects of the demand side of energy to aid the design of better policies and programmes. Future research needs for improving the practice of ABM to better understand energy demand are also discussed.

Secure Route Structures for Parallel Mobile Agents Based Systems Using Fast Binary Dispatch

Directory of Open Access Journals (Sweden)

Yan Wang

2005-01-01

Full Text Available In a distributed environment, where a large number of computers are connected together to enable the large-scale sharing of data and computing resources, agents, especially mobile agents, are the tools for autonomously completing tasks on behalf of their owners. For applications of large-scale mobile agents, security and efficiency are of great concern. In this paper, we present a fast binary dispatch model and corresponding secure route structures for mobile agents dispatched in parallel to protect the dispatch routes of agents while ensuring the dispatch efficiency. The fast binary dispatch model is simple but efficient with a dispatch complexity of O(log2n. The secure route structures adopt the combination of public-key encryption and digital signature schemes and expose minimal route information to hosts. The nested structure can help detect attacks as early as possible. We evaluated the various models both analytically and empirically.

Efficient priority queueing routing strategy on networks of mobile agents

Science.gov (United States)

Wu, Gan-Hua; Yang, Hui-Jie; Pan, Jia-Hui

2018-03-01

As a consequence of their practical implications for communications networks, traffic dynamics on complex networks have recently captivated researchers. Previous routing strategies for improving transport efficiency have paid little attention to the orders in which the packets should be forwarded, just simply used first-in-first-out queue discipline. Here, we apply a priority queuing discipline and propose a shortest-distance-first routing strategy on networks of mobile agents. Numerical experiments reveal that the proposed scheme remarkably improves both the network throughput and the packet arrival rate and reduces both the average traveling time and the rate of waiting time to traveling time. Moreover, we find that the network capacity increases with an increase in both the communication radius and the number of agents. Our work may be helpful for the design of routing strategies on networks of mobile agents.

VBOT: Motivating computational and complex systems fluencies with constructionist virtual/physical robotics

Science.gov (United States)

Berland, Matthew W.

As scientists use the tools of computational and complex systems theory to broaden science perspectives (e.g., Bar-Yam, 1997; Holland, 1995; Wolfram, 2002), so can middle-school students broaden their perspectives using appropriate tools. The goals of this dissertation project are to build, study, evaluate, and compare activities designed to foster both computational and complex systems fluencies through collaborative constructionist virtual and physical robotics. In these activities, each student builds an agent (e.g., a robot-bird) that must interact with fellow students' agents to generate a complex aggregate (e.g., a flock of robot-birds) in a participatory simulation environment (Wilensky & Stroup, 1999a). In a participatory simulation, students collaborate by acting in a common space, teaching each other, and discussing content with one another. As a result, the students improve both their computational fluency and their complex systems fluency, where fluency is defined as the ability to both consume and produce relevant content (DiSessa, 2000). To date, several systems have been designed to foster computational and complex systems fluencies through computer programming and collaborative play (e.g., Hancock, 2003; Wilensky & Stroup, 1999b); this study suggests that, by supporting the relevant fluencies through collaborative play, they become mutually reinforcing. In this work, I will present both the design of the VBOT virtual/physical constructionist robotics learning environment and a comparative study of student interaction with the virtual and physical environments across four middle-school classrooms, focusing on the contrast in systems perspectives differently afforded by the two environments. In particular, I found that while performance gains were similar overall, the physical environment supported agent perspectives on aggregate behavior, and the virtual environment supported aggregate perspectives on agent behavior. The primary research questions

Towards a dynamic model of supply chain regimes for complex multi-agent markets

NARCIS (Netherlands)

Hogenboom, A.C.; Hogenboom, F.P.; Kaymak, U.; Ketter, W.; Dalen, van Jan; Collins, J.

2010-01-01

Information systems are crucial for effective supply chain management in today's complex supply chains for durable goods. Complex decision making processes on strategic, tactical, and operational level require substantial support in order to contribute to the agility of organizations. Supply chain

Newly Synthesized Doxorubicin Complexes with Selected Metals—Synthesis, Structure and Anti-Breast Cancer Activity

Directory of Open Access Journals (Sweden)

Agata Jabłońska-Trypuć

2017-07-01

Full Text Available Doxorubicin (DOX is very effective chemotherapeutic agent, however it has several major drawbacks. Therefore the motivation for developing novel drug complexes as anticancer agents with different mechanism of action has arisen. The aim of the present study was to evaluate the influence of newly synthesized DOX complexes with selected metals (Mg, Mn, Co, Ni, Fe, Cu, Zn on apoptosis, cell cycle, viability, proliferation and cytotoxicity in the breast cancer cell line MCF-7. Complexation of DOX with metals has likewise been the subject of our research. The current work showed that the tested bivalent metals at a given pH condition formed metal:DOX complexes in a ratio of 2:1, while iron complexes with DOX in a ratio of 3:1. The studies also showed that selected metal-DOX complexes (Mg-DOX, Mn-DOX, Ni-DOX at 0.5 µM concentration significantly decreased cell viability and proliferation, however they increased caspase 7 activity. Results also indicated that studied metal-DOX complexes showed high cytotoxicity in MCF-7 cells. Therefore they were chosen for cell cycle check-points and apoptosis/necrosis analysis studied by flow cytometry. Obtained results suggest that doxorubicin complexed by specified metals can be considered as a potential anti-breast cancer agent, which is characterized by a higher efficacy than a parent drug.

Recent developments in antiviral agents against enterovirus 71 infection.

Science.gov (United States)

Tan, Chee Wah; Lai, Jeffrey Kam Fatt; Sam, I-Ching; Chan, Yoke Fun

2014-02-12

Enterovirus 71 (EV-71) is the main etiological agent of hand, foot and mouth disease (HFMD). Recent EV-71 outbreaks in Asia-Pacific were not limited to mild HFMD, but were associated with severe neurological complications such as aseptic meningitis and brainstem encephalitis, which may lead to cardiopulmonary failure and death. The absence of licensed therapeutics for clinical use has intensified research into anti-EV-71 development. This review highlights the potential antiviral agents targeting EV-71 attachment, entry, uncoating, translation, polyprotein processing, virus-induced formation of membranous RNA replication complexes, and RNA-dependent RNA polymerase. The strategies for antiviral development include target-based synthetic compounds, anti-rhinovirus and poliovirus libraries screening, and natural compound libraries screening. Growing knowledge of the EV-71 life cycle will lead to successful development of antivirals. The continued effort to develop antiviral agents for treatment is crucial in the absence of a vaccine. The coupling of antivirals with an effective vaccine will accelerate eradication of the disease.

Contrast agents for cardiac angiography: effects of a nonionic agent vs. a standard ionic agent

International Nuclear Information System (INIS)

Bettmann, M.A.; Bourdillon, P.D.; Barry, W.H.; Brush, K.A.; Levin, D.C.

1984-01-01

The effects on cardiac hemodynamics and of a standard contrast agent, sodium methylglucamine diatrizoate [Renografin 76] were compared with the effects of a new nonionic agent (iohexol) in a double-blind study in 51 patietns undergoing coronary angiography and left ventriculography. No significant alteration in measured blood parameters occurred with either contrast agent. Hemodynamic changes occurred with both, but were significantly greater with the standard renografin than with the low-osmolality, nonionic iohexol. After left ventriculography, heart rate increased and peripheral arterial pressure fell with both agents, but less with iohexol. It is concluded that iohexol causes less alteration in cardiac function than does the agent currently most widely used. Nonionic contrast material is likely to improve the safety of coronary angiography, particularly in those patients at greatest risk

On the engineering design for systematic integration of agent-orientation in industrial automation.

Science.gov (United States)

Yu, Liyong; Schüller, Andreas; Epple, Ulrich

2014-09-01

In today's automation industry, agent-oriented development of system functionalities appears to have a great potential for increasing autonomy and flexibility of complex operations, while lowering the workload of users. In this paper, we present a reference model for the harmonious and systematical integration of agent-orientation in industrial automation. Considering compatibility with existing automation systems and best practice, this model combines advantages of function block technology, service orientation and native description methods from the automation standard IEC 61131-3. This approach can be applied as a guideline for the engineering design of future agent-oriented automation systems. Copyright © 2014 ISA. Published by Elsevier Ltd. All rights reserved.

Ln(III)-malate complexation studies using TRLFS and micro titration calorimetry

International Nuclear Information System (INIS)

Taube, F.; Drobot, B.; Acker, M.; Taut, S.; Stumpf, Thorsten

2017-01-01

The complexation of trivalent lanthanides was studied using Time-Resolved Laser-Induced Fluorescence Spectroscopy (TRLFS) and Isothermal Titration Calorimetry (ITC). Formation constants, complexation enthalpies and fluorescence lifetimes are determined over a wide pH range at I = 0.5 m NaCl. This subject has the following background: Concrete is widely used as engineering barrier and for waste conditioning in waste repositories. Its binding agent is cement. Organic cement additives, which are used to improve the workability of fresh concrete, are complexation agents for radionuclides after they have been released during the concretes degradation. Thus, these additives might have an impact on the aqueous geochemistry of actinides. Here, the α-hydroxydicarboxylic acid or malic acid is examined. It is used in water-reducers or retarders in cement.

Ln(III)-malate complexation studies using TRLFS and micro titration calorimetry

Energy Technology Data Exchange (ETDEWEB)

Taube, F.; Drobot, B. [Technische Univ. Dresden (Germany). Professorship Radiochemistry; Acker, M.; Taut, S. [Technische Univ. Dresden (Germany). Central Radionuclide Laboratory; Stumpf, Thorsten [Helmholtz-Zentrum Dresden-Rossendorf e.V., Dresden (Germany). Inst. of Resource Ecology

2017-06-01

The complexation of trivalent lanthanides was studied using Time-Resolved Laser-Induced Fluorescence Spectroscopy (TRLFS) and Isothermal Titration Calorimetry (ITC). Formation constants, complexation enthalpies and fluorescence lifetimes are determined over a wide pH range at I = 0.5 m NaCl. This subject has the following background: Concrete is widely used as engineering barrier and for waste conditioning in waste repositories. Its binding agent is cement. Organic cement additives, which are used to improve the workability of fresh concrete, are complexation agents for radionuclides after they have been released during the concretes degradation. Thus, these additives might have an impact on the aqueous geochemistry of actinides. Here, the α-hydroxydicarboxylic acid or malic acid is examined. It is used in water-reducers or retarders in cement.

An agent-oriented approach to automated mission operations

Science.gov (United States)

Truszkowski, Walt; Odubiyi, Jide

1994-01-01

As we plan for the next generation of Mission Operations Control Center (MOCC) systems, there are many opportunities for the increased utilization of innovative knowledge-based technologies. The innovative technology discussed is an advanced use of agent-oriented approaches to the automation of mission operations. The paper presents an overview of this technology and discusses applied operational scenarios currently being investigated and prototyped. A major focus of the current work is the development of a simple user mechanism that would empower operations staff members to create, in real time, software agents to assist them in common, labor intensive operations tasks. These operational tasks would include: handling routine data and information management functions; amplifying the capabilities of a spacecraft analyst/operator to rapidly identify, analyze, and correct spacecraft anomalies by correlating complex data/information sets and filtering error messages; improving routine monitoring and trend analysis by detecting common failure signatures; and serving as a sentinel for spacecraft changes during critical maneuvers enhancing the system's capabilities to support nonroutine operational conditions with minimum additional staff. An agent-based testbed is under development. This testbed will allow us to: (1) more clearly understand the intricacies of applying agent-based technology in support of the advanced automation of mission operations and (2) access the full set of benefits that can be realized by the proper application of agent-oriented technology in a mission operations environment. The testbed under development addresses some of the data management and report generation functions for the Explorer Platform (EP)/Extreme UltraViolet Explorer (EUVE) Flight Operations Team (FOT). We present an overview of agent-oriented technology and a detailed report on the operation's concept for the testbed.

Complexing Agents on Carbon Content and Lithium Storage Capacity of LiFePO4/C Cathode Synthesized via Sol-Gel Approach

Directory of Open Access Journals (Sweden)

C. Guan

2016-01-01

Full Text Available Olivine-structured LiFePO4 faces its intrinsic challenges in terms of poor electrical conductivity and lithium-ion diffusion capability for application to lithium-ion batteries. Cost-effective sol-gel approach is advantageous to in situ synthesize carbon-coated LiFePO4 (LiFePO4/C which can not only improve electronic conductivity but also constrain particle size to nanometer scale. In this study, the key parameter is focused on the choice and amount of chelating agents in this synthesis route. It was found that stability of complexing compounds has significant impacts on the carbon contents and electrochemical properties of the products. At the favorable choice of precursors, composition, and synthesis conditions, nanocrystalline LiFePO4/C materials with appropriate amount of carbon coating were successfully obtained. A reversible capacity of 162 mAh/g was achieved at 0.2C rate, in addition to good discharge rate capability.

Pharmacological agents and impairment of fracture healing: what is the evidence?

NARCIS (Netherlands)

Pountos, I.; Georgouli, T.; Blokhuis, T.J.; Pape, H.C.; Giannoudis, P.V.

2008-01-01

Bone healing is an extremely complex process which depends on the coordinated action of several cell lineages on a cascade of biological events, and has always been a major medical concern. The use of several drugs such as corticosteroids, chemotherapeutic agents, non-steroidal anti-inflammatory

Biotin-tagged platinum(iv) complexes as targeted cytostatic agents against breast cancer cells.

Science.gov (United States)

Muhammad, Nafees; Sadia, Nasreen; Zhu, Chengcheng; Luo, Cheng; Guo, Zijian; Wang, Xiaoyong

2017-09-05

A biotin-guided platinum IV complex is highly cytotoxic against breast cancer cells but hypotoxic against mammary epithelial cells. The mono-biotinylated Pt IV complex is superior to the di-biotinylated one and hence a promising drug candidate for the targeted therapy of breast cancer.

Uncertainty analysis in agent-based modelling and consequential life cycle assessment coupled models : a critical review

NARCIS (Netherlands)

Baustert, P.M.; Benetto, E.

2017-01-01

The evolution of life cycle assessment (LCA) from a merely comparative tool for the assessment of products to a policy analysis tool proceeds by incorporating increasingly complex modelling approaches. In more recent studies of complex systems, such as the agriculture sector or mobility, agent-based

An agent-based approach equipped with game theory. Strategic collaboration among learning agents during a dynamic market change in the California electricity crisis

Energy Technology Data Exchange (ETDEWEB)

Sueyoshi, Toshiyuki [Department of Management, New Mexico Institute of Mining and Technology, Socorro, NM 87801 (United States); Department of Industrial and Information Management, National Cheng Kung University, Tainan (China)

2010-09-15

An agent-based approach is a numerical (computer-intensive) method to explore the complex characteristics and dynamics of microeconomics. Using the agent-based approach, this study investigates the learning speed of traders and their strategic collaboration in a dynamic market change of electricity. An example of such a market change can be found in the California electricity crisis (2000-2001). This study incorporates the concept of partial reinforcement learning into trading agents and finds that they have two learning components: learning from a dynamic market change and learning from collaboration with other traders. The learning speed of traders becomes slow when a large fluctuation occurs in the power exchange market. The learning speed depends upon the type of traders, their learning capabilities and the fluctuation of market fundamentals. The degree of collaboration among traders gradually reduces during the electricity crisis. The strategic collaboration among traders is examined by a large simulator equipped with multiple learning capabilities. (author)

An agent-based approach equipped with game theory. Strategic collaboration among learning agents during a dynamic market change in the California electricity crisis

International Nuclear Information System (INIS)

Sueyoshi, Toshiyuki

2010-01-01

An agent-based approach is a numerical (computer-intensive) method to explore the complex characteristics and dynamics of microeconomics. Using the agent-based approach, this study investigates the learning speed of traders and their strategic collaboration in a dynamic market change of electricity. An example of such a market change can be found in the California electricity crisis (2000-2001). This study incorporates the concept of partial reinforcement learning into trading agents and finds that they have two learning components: learning from a dynamic market change and learning from collaboration with other traders. The learning speed of traders becomes slow when a large fluctuation occurs in the power exchange market. The learning speed depends upon the type of traders, their learning capabilities and the fluctuation of market fundamentals. The degree of collaboration among traders gradually reduces during the electricity crisis. The strategic collaboration among traders is examined by a large simulator equipped with multiple learning capabilities. (author)

Smart Aerospace eCommerce: Using Intelligent Agents in a NASA Mission Services Ordering Application

Science.gov (United States)

Moleski, Walt; Luczak, Ed; Morris, Kim; Clayton, Bill; Scherf, Patricia; Obenschain, Arthur F. (Technical Monitor)

2002-01-01

This paper describes how intelligent agent technology was successfully prototyped and then deployed in a smart eCommerce application for NASA. An intelligent software agent called the Intelligent Service Validation Agent (ISVA) was added to an existing web-based ordering application to validate complex orders for spacecraft mission services. This integration of intelligent agent technology with conventional web technology satisfies an immediate NASA need to reduce manual order processing costs. The ISVA agent checks orders for completeness, consistency, and correctness, and notifies users of detected problems. ISVA uses NASA business rules and a knowledge base of NASA services, and is implemented using the Java Expert System Shell (Jess), a fast rule-based inference engine. The paper discusses the design of the agent and knowledge base, and the prototyping and deployment approach. It also discusses future directions and other applications, and discusses lessons-learned that may help other projects make their aerospace eCommerce applications smarter.

Perianal injectable bulking agents as treatment for faecal incontinence in adults. (Update)

DEFF Research Database (Denmark)

Maeda, Yasuko; Laurberg, Søren; Norton, Christine

2013-01-01

BACKGROUND: Faecal incontinence is a complex and distressing condition with significant medical and social implications. Injection of perianal bulking agents has been used to treat the symptoms of passive faecal incontinence. However, various agents have been used without a standardised technique...... evaluation of outcomes and thus it is difficult to gauge whether the improvement in incontinence scores matched practical symptom improvements that mattered to the patients. AUTHORS' CONCLUSIONS: One large randomised controlled trial has shown that this form of treatment using dextranomer in stabilised...

An Agent-Based Model for Studying Child Maltreatment and Child Maltreatment Prevention