Science.gov

Sample records for coupling agent gamma-aminopropyltriethoxysilane

  1. Infrared analysis of the effect of composition of n-butyltriethoxysilane and gamma-aminopropyltriethoxysilane blends on tertiary amine-catalyzed anhydride-cured epoxy mixtures. Technical report

    SciTech Connect

    Tidrick, S.L.; Ishida, H.; Koenig, J.L.

    1991-05-01

    The enhancement in mechanical properties observed for silane-treated glass-reinforced epoxy materials is highly dependent on the structure of the coupling agent at the interphase. The effect of varying composition of nonhydrolyzed silane coupling agent blends of gamma aminopropyltriethoxysilane (APS) and butyltriethoxysilane (BTS) on the cure of benzyldimethylamine (BDMA)-catalyzed, nadic methyl anhydride (NMA)-cured diglycidyl ether of bisphenol-A epoxy (BDGE) was studied by Fourier transform infrared spectroscopy (FTIR). The silane blends perturbed the kinetics of the alternating anhydride-epoxy copolymerization reaction, with the perturbation being a nonlinear function of the relative amine concentration in the system.

  2. Test of carcinogenicity in mouse skin: Methylenedianiline,. gamma. glycidyloxytrimethyloxysilane,. gamma. aminopropyltriethoxysilane and a mixture of m-phenylenediamine, methylenedianiline, and diglycidylether of bisphenol-A

    SciTech Connect

    Holland, J.M.; Smith, L.H.; Frome, E.; Whitaker, M.J.; Gipson, L.C.; Fry, R.J.M.

    1987-06-01

    Application of graded concentrations of four test substances in acetone to the skin of C3H mice five times a week resulted in the following: ..gamma..aminopropyltriethoxysilane at concentration of 100 and 50 wt/vol % was a severe and mild skin irritant in female C3Hf/Bd respectively and in males a mild skin irritant. Methylenedianiline at a concentration of 10 wt/vol % in methanol killed 4/9 females and 1/9 males. When acetone was the solvent 3/10 females and 3/10 males died within 2 weeks. No mortality or skin damage occurred with ..gamma..glycidyloxytrimethyloxysilane or the mixture of m-phenylenediamine, methylenedianiline and diglycidylether of bisphenol A (MDA). A study of the effects of a two-year, three times a week, topical application of the four test materials revealed no significant increase in skin tumors. The incidence of liver tumors appeared to be increased by exposure to methylenedianiline and with the mixture (MDA). Significant and dose-dependent increases in mortality were found in male mice with MDA and increased mortality at the highest dose (10.8 mg/week) in females. In the case of methylenedianiline excess mortality was found in both sexes. The precise cause of excess mortality from dermal absorption of the materials applied over a two-year period was not established. 5 refs., 12 figs., 12 tabs.

  3. Multifunctional nanoparticles as coupled contrast agents

    PubMed Central

    Jin, Yongdong; Jia, Congxian; Huang, Sheng-Wen; O’Donnell, Matthew; Gao, Xiaohu

    2011-01-01

    Engineering compact imaging probes with highly integrated modalities is a key focus in bionanotechnology and will have profound impact on molecular diagnostics, imaging, and therapeutics. However, combining multiple components on a nanometer scale to create new imaging modalities unavailable from individual components has proven challenging. Here, we demonstrate iron oxide and gold coupled core-shell nanoparticles with well defined structural characteristics (e.g., size, shell thickness, and core-shell separation) and physical properties (e.g., electronic, magnetic, optical, thermal, and acoustic). The resulting multifunctional nanoprobes not only offer contrast for electron microscopy, magnetic resonance imaging, and scattering-based imaging, but more importantly, enable a new imaging mode, magnetomotive photoacoustic (mmPA) imaging, with remarkable contrast enhancement compared to PA images using conventional nanoparticle contrast agents. PMID:20975706

  4. Silane coupling agent structures on carbon nanofibers.

    PubMed

    Palencia, Cristina; Rubio, Juan; Rubio, Fausto; Fierro, José Luis G; Oteo, José Luis

    2011-05-01

    Carbon nanofibers (CNFs) are considered ideal materials for reinforcing polymers due to their excellent mechanical properties, among others. In order to obtain composites of optimal properties the clue is to enhance the interaction between reinforcement (CNFs) and polymer matrix. Surface modification of CNFs with silane coupling agents (SCAs) has revealed as one of the most interesting methods. The silanization process has been carried out mixing at room temperature and for one minute the hydrolysed silane with CNFs. We have use four different SCAs: 3-aminopropyltriethoxyxilane (APS), 3-aminopropyltrimethoxysilane (AMMO), N-(2-aminoethyl)-3-(aminopropyltrimethoxysilane) (DAMO), and 3-glycidoxypropyltrimethoxysilane (GLYMO), in order to elucidate the SCA-CNFs interaction and the silane structures formed on CNFs surface. XPS and FTIR-ATR techniques have pointed out that each silane adsorbs on CNFs surface through chemical bonding, forming multilayers. Silane nature determines the structure taken on CNFs surface. APS and AMO silanes adsorb taking vertical structures on CNFs surface, while DMO and GMO adsorb on CNFs taking horizontal structures, stabilized by zwitterions formed through H-bonds with hydroxyl groups from CNFs surface. PMID:21780418

  5. Development of high temperature resistant graphite fiber coupling agents

    NASA Technical Reports Server (NTRS)

    Griffin, R. N.

    1975-01-01

    Surface treatments were investigated as potential coupling agents to improve the elevated temperature shear strength retention of polyimide/graphite and polyphenylquinoxaline/graphite composites. The potential coupling agents were evaluated by fiber strand tensile tests, fiber and composite weight losses at 533 and 588K, and by interlaminar shear strength retention at 533 and 588K. The two surface treatments selected for more extensive evaluation were a coating of Ventromer T-1, a complex organometallic reaction product of titanium tetrachloride and trimethyl borate, and a polyphenylquinoxaline (PPQ) sizing which was pyrolyzed in nitrogen to form a carbonaceous layer on the fiber. Pyrolyzed polyphenylquinoxaline is a satisfactory coupling agent for polyimide/Thornel 300 graphite fiber composites. During 1000 hours aging at 588K such composites lose a little over half their transverse tensile strength, and suffer a slight loss in flexural modulus. No degradation of flexural strength or interlaminar shear strength occured during 1000 hours aging at 588K. None of the coupling agents examined had a markedly beneficial effect with polyphenylquinoxaline composites.

  6. The effect of coupling agents on composite durability

    SciTech Connect

    Macturk, K.S.; Schultheisz, C.R.; Hunston, D.L.; Schutte, C.L.

    1996-12-31

    The relationship between fiber surface treatments and glass fiber/epoxy composite durability was investigated. The type of silane coupling agent deposited on the fiber surface was varied, and the single fiber fragmentation test was used to measure strengths of the fiber and the fiber-matrix interface. The samples were tested dry and after conditioned in 75{degrees}C distilled water for up to 10 weeks. With dry samples the interface strengths varied with the reactivity of the silane deposited on the surface. Moisture exposure produced little change in fiber strengths and, for samples containing silane treated fibers, little change in interface strength, even when the silane was unreactive with the epoxy. In contrast, samples containing unsized fibers exhibited significant losses in interface strengths.

  7. Delay-dependent coupling for a multi-agent LTI consensus system with inter-agent delays

    NASA Astrophysics Data System (ADS)

    Qiao, Wei; Sipahi, Rifat

    2014-01-01

    Delay-dependent coupling (DDC) is considered in this paper in a broadly studied linear time-invariant multi-agent consensus system in which agents communicate with each other under homogeneous delays, while attempting to reach consensus. The coupling among the agents is designed here as an explicit parameter of this delay, allowing couplings to autonomously adapt based on the delay value, and in order to guarantee stability and a certain degree of robustness in the network despite the destabilizing effect of delay. Design procedures, analysis of convergence speed of consensus, comprehensive numerical studies for the case of time-varying delay, and limitations are presented.

  8. Modification of eucalyptus pulp fiber using silane coupling agents with aliphatic side chains of different length

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The objective of this work was to evaluate the effect of three silane coupling agents with different aliphatic chain lengths on the hydrophobicity of eucalyptus pulp fiber. The three silanes coupling agents used (isobutyltrimethoxysilane, methyltrimethoxysilane, and n-octyltriethoxysilane [OTES]) we...

  9. Surface modification of basalt with silane coupling agent on asphalt mixture moisture damage

    NASA Astrophysics Data System (ADS)

    Min, Yahong; Fang, Ying; Huang, Xiaojun; Zhu, Yinhui; Li, Wensheng; Yuan, Jianmin; Tan, Ligang; Wang, Shuangyin; Wu, Zhenjun

    2015-08-01

    A new silane coupling agent was synthesized based on γ-(methacryloyloxy) propyltrimethoxysilane (KH570). The surface of basalt rocks was modified by KH570 and the new silane coupling agent (NSCA), and the interfacial interaction between silane coupling agent and basalt was also studied. Fourier transform infrared (FTIR) spectroscopy and X-ray photoelectron spectroscopy (XPS) analysis showed that the silane coupling agent molecule bound strongly with basalt rocks. Scanning electronic microscopy (SEM) observation showed that a thin layer of coupling agent was formed on the surface of modified basalt. The boiling test and immersion Marshall test confirmed that the moisture sensitivity of basalt modified with the new silane coupling agent increased more significantly than that untreated and treated with KH570. The Retained Marshall Strength of basalt modified with the new coupling agent increased from 71.74% to 87.79% compared with untreated basalt. The results indicated that the new silane coupling agent played an important role in improving the interfacial performance between basalt and asphalt.

  10. Further development of high temperature-resistant graphite fiber coupling agents

    NASA Technical Reports Server (NTRS)

    Griffin, R. N.

    1976-01-01

    Potential coupling agents for graphite fibers were screened by their effect on the weight losses of Thornel 300, HMS, and HTS fibers at 588K for 200 and 400 hours. Unidirectional laminates were made from HMS and HTS fibers, untreated, and treated with each of the seven coupling agents. The matrix of all laminates was PMR polyimide (PMR-PR). On the basis of the best overall retention of elevated temperature interlaminar shear strength after 200 hours at 588K, composite weight after 200 hours at 588K, and fiber weight after 400 hours at 588K, ventromer T-1 applied from aqueous solution and pyrolyzed PPQ were selected for further evaluation as coupling agents for HTS fiber while ventromer T-2 and pyrolyzed PPQ were selected as coupling agents for HMS fiber. It was shown that pyrolyzed PPQ as a coupling agent improves the oxidative stability of HTS/PMR-PI composites.

  11. Use of titanate coupling agents in Kevlar (trade name)/phenolic composites

    SciTech Connect

    Menon, N.; Blum, F.D.; Dharani, L.R.

    1994-04-02

    Surface modification of Kevlar(R) fibers with titanate coupling agents for improved adhesion of the fiber and resin in Kevlar(R)/phenolic composites has been attempted to explore the possibility of enhancement in adhesion and bulk properties of composites for friction materials. Titanate coupling agents were used and flexural properties of the Kevlar(R)-fiber reinforced composites determined. A study of different amounts of the coupling agents at the fiber-matrix interface suggested that 2% by weight of fiber was the optimum amount, in terms of improvement in flexural properties. The composite samples with the coupling agents, showed an increase in flexural strength, over the untreated samples with the maximum increase being approx. 18% over the control. Water absorption studies were conducted on Kevlar(R)/phenolic composites treated with organotitanates to determine the effectiveness of these coupling agents in improving resistance to moisture attack. The treated Kevlar(R)/phenolic composite samples exhibited greater resistance to moisture-ingress over the untreated samples. The control samples showed a decrease of 17% in flexural strength. The largest decrease in strength was 14% for the treated samples containing coupling agent tetrakis(2-ethylhexyl)titanate (TYZOR TOT). Recovery in strength on reconditioning, was also greater for treated samples over control. A recovery in strength of ca. 94% was seen for some treated samples. Coupling agents, Composites, Kevlar, Interfaces, Mechanical properties.

  12. The effect of water resistance in the primary coating by silane coupling agents and amine synergists

    NASA Astrophysics Data System (ADS)

    Kim, Min-Jeong; Min, Kyoungbeom; Kim, Sanghwan; Yoon, Jung-Woo; Kwak, Seungjo; Lee, Ji-hye; Oh, Sungkoog

    2008-11-01

    In order to clarify the relationship between the water resistance and compositional additives in the primary coating for optical fibers, we prepared various primary coatings that contained silane coupling agents in combination with amine synergists. We observed the appearance of the interface between glass and primary coating after soaking in water at 65° for 30 days. Water resistance was found to be heavily influenced by the content and type of silane coupling agents and amine synergists and their trends are reported.

  13. Bond strength between fiber posts and composite resin core: influence of temperature on silane coupling agents.

    PubMed

    Novais, Veridiana Resende; Simamotos Júnior, Paulo Cézar; Rontani, Regina Maria Puppin; Correr-Sobrinho, Lourenço; Soares, Carlos José

    2012-01-01

    This study evaluated the effect of air drying temperature and different silane coupling agents on the bond strength between glass fiber posts and composite resin core. The post surface was cleaned with alcohol and treated with different silane coupling agents, being three prehydrolyzed silanes [Silano (Angelus), Prosil (FGM), RelyX Ceramic Primer (3M ESPE)] and one two-component silane [Silane Coupling Agent (Dentsply)]. Two post-silanization air drying temperatures, 23ºC and 60ºC, were applied. A cylindrical plastic matrix was placed around the silanized post and filled with composite resin. Each bonded post provided 7 slices for push-out testing. Each slice was loaded to failure under compression at a cross-head speed of 0.5 mm/min. Data were analyzed by two-way ANOVA and Scott-Knott tests (?=0.05). Dunnett's test was used to compare the mean of the control group with that of each experimental group. Scanning electron microscopy (SEM) was used to evaluate the interface of the fractured slices. For the 23ºC air drying temperature, the use of RelyX Ceramic Primer resulted in significantly lower bond strength than the other silane coupling agents, while the bond strength with Silane Coupling Agent was the highest of all groups. Only with Silane Coupling Agent, the bond strength for the 23ºC air drying temperature was significantly higher than that for 60ºC air drying. In conclusion, the use of warm air drying after silane application produced no increase in the bond strength between the fiber-reinforced composite post and the composite core. The two-component silane produced higher bond strength than all prehydrolyzed silanes when it was used with air drying at room temperature. PMID:22460308

  14. Recyclable polystyrene-supported siloxane-transfer agent for palladium-catalyzed cross-coupling reactions.

    PubMed

    Nguyen, Minh H; Smith, Amos B

    2014-04-01

    The rational design, synthesis, and validation of a significantly improved insoluble polymer-supported siloxane-transfer agent has been achieved that permits efficient palladium-catalyzed cross-coupling reactions. The cross-linked polystyrene support facilitates product purification with excellent siloxane recycling. Drawbacks of a previous polymer-supported siloxane-transfer agent, relating to reaction efficiency and polymer stability after repeated cycles, have been addressed. PMID:24661113

  15. Impact of biofibers and coupling agents on the weathering characteristics of composites polymer degradation and stability

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This paper explores the ultraviolet (UV) weathering performance of high density polyethylene (HDPE) composites with different biofiber fillers and coupling agent. Biofiber polymer composite (BFPC) material samples were prepared using oak, cotton burr and stem (CBS) or guayule bagasse as fiber source...

  16. Development and Evaluation of Novel Coupling Agents for Kenaf-Fiber-Reinforced Unsaturated Polyester Composites

    NASA Astrophysics Data System (ADS)

    Ren, Xiaofeng

    Natural fibers are gaining popularity as reinforcement materials for thermoset resins over the last two decades. Natural fibers are inexpensive, abundant, renewable and environmentally friendly. Kenaf fibers are one of the natural fibers that can potentially be used for reinforcing unsaturated polyester (UPE). As a polymer matrix, UPE enjoys a 40% market share of all the thermoset composites. This widespread application is due to many favorable characteristics including low cost, ease of cure at room temperature, ease of molding, a good balance of mechanical, electrical and chemical properties. One of the barriers for the full utilization of the kenaf fiber reinforced UPE composites, however, is the poor interfacial adhesion between the natural fibers and the UPE resins. The good interfacial adhesion between kenaf fibers and UPE matrix is essential for generating the desired properties of kenaf-UPE composites for most of the end applications. Use of a coupling agent is one of the most effective ways of improving the interfacial adhesion. In this study, six novel effective coupling agents were developed and investigated for kenaf-UPE composites: DIH-HEA, MFA, NMA, AESO-DIH, AESO-MDI, and AESO-PMDI. All the coupling agents were able to improve the interfacial adhesion between kanaf and UPE resins. The coupling agents were found to significantly enhance the flexural properties and water resistance of the kenaf-UPE composites. Fourier transform infrared spectroscopy (FTIR) confirmed all the coupling agents were covalently bonded onto kenaf fibers. Scanning electron microscopy (SEM) images of the composites revealed the improved interfacial adhesion between kanaf fibers and UPE resins.

  17. Influence of coupling agent chain lengths on interfacial performances of polyarylacetylene resin and silica glass composites

    NASA Astrophysics Data System (ADS)

    Jiang, Z. X.; Meng, L. H.; Huang, Y. D.; Liu, L.; Lu, C.

    2007-02-01

    The influence of chain lengths on interfacial performances of polyarylacetylene (PAA)/silica glass composites was studied. In order to obtain different chain lengths on substrates, methyltrimethoxysilane, propyltrimethoxysilane, octyltrimethoxysilane and dodecyltrimethoxysilane were grafted onto silica glass surface. Topographies of silica glass surface and the wetting ability of PAA resin on silica glass surface were characterized by atomic force microscopy (AFM) and surface free energy along with contact angles, respectively. At the same time, the interfacial adhesion was evaluated by shear strength testing. The failure mechanisms of composites were also analyzed by fracture morphologies. The results of the study indicate that with chain lengths of coupling agents on silica glass surface increasing, interfacial shear strengths of PAA/silica glass composites increase, while the wetting ability of PAA resin on silica glass surface decreases. The main mechanism for the improvement of the interfacial adhesion is physical entanglement interaction between the chain of coupling agent and the chain of PAA resin.

  18. Agent-based Model for the Coupled Human-Climate System

    NASA Astrophysics Data System (ADS)

    Zvoleff, A.; Werner, B.

    2006-12-01

    Integrated assessment models have been used to predict the outcome of coupled economic growth, resource use, greenhouse gas emissions and climate change, both for scientific and policy purposes. These models generally have employed significant simplifications that suppress nonlinearities and the possibility of multiple equilibria in both their economic (DeCanio, 2005) and climate (Schneider and Kuntz-Duriseti, 2002) components. As one step toward exploring general features of the nonlinear dynamics of the coupled system, we have developed a series of variations on the well studied RICE and DICE models, which employ different forms of agent-based market dynamics and "climate surprises." Markets are introduced through the replacement of the production function of the DICE/RICE models with an agent-based market modeling the interactions of producers, policymakers, and consumer agents. Technological change and population growth are treated endogenously. Climate surprises are representations of positive (for example, ice sheet collapse) or negative (for example, increased aerosols from desertification) feedbacks that are turned on with probability depending on warming. Initial results point toward the possibility of large amplitude instabilities in the coupled human-climate system owing to the mismatch between short outlook market dynamics and long term climate responses. Implications for predictability of future climate will be discussed. Supported by the Andrew W Mellon Foundation and the UC Academic Senate.

  19. Development of polypropylene/wood flour ecocomposites. Evaluation of silane as coupling agent

    SciTech Connect

    Bouza, R.; Barral, L.; Abad, M. J.; Montero, B.

    2010-06-02

    The effects of Pinus Sylvestris wood flour as filler in polypropylene matrix was evaluated. The mechanical properties and the morphology of different wood flour/polypropylene composites (WPC) were studied. The composites materials were prepared with several amounts of wood flour from 10 to 30% wt. Mechanical properties show that the wood flour incorporation increases the rigidity of the composites. Morphological analysis indicates that agglomerates are formed, with amounts exceeding 30% of wood flour. For the silane--treated composites, the dispersion of the filler into the polypropylene (PP) matrix improved. Shore D hardness of the composites is decreased with the addition of the coupling agent.

  20. Coupled agent-based and finite-element models for predicting scar structure following myocardial infarction.

    PubMed

    Rouillard, Andrew D; Holmes, Jeffrey W

    2014-08-01

    Following myocardial infarction, damaged muscle is gradually replaced by collagenous scar tissue. The structural and mechanical properties of the scar are critical determinants of heart function, as well as the risk of serious post-infarction complications such as infarct rupture, infarct expansion, and progression to dilated heart failure. A number of therapeutic approaches currently under development aim to alter infarct mechanics in order to reduce complications, such as implantation of mechanical restraint devices, polymer injection, and peri-infarct pacing. Because mechanical stimuli regulate scar remodeling, the long-term consequences of therapies that alter infarct mechanics must be carefully considered. Computational models have the potential to greatly improve our ability to understand and predict how such therapies alter heart structure, mechanics, and function over time. Toward this end, we developed a straightforward method for coupling an agent-based model of scar formation to a finite-element model of tissue mechanics, creating a multi-scale model that captures the dynamic interplay between mechanical loading, scar deformation, and scar material properties. The agent-based component of the coupled model predicts how fibroblasts integrate local chemical, structural, and mechanical cues as they deposit and remodel collagen, while the finite-element component predicts local mechanics at any time point given the current collagen fiber structure and applied loads. We used the coupled model to explore the balance between increasing stiffness due to collagen deposition and increasing wall stress due to infarct thinning and left ventricular dilation during the normal time course of healing in myocardial infarcts, as well as the negative feedback between strain anisotropy and the structural anisotropy it promotes in healing scar. The coupled model reproduced the observed evolution of both collagen fiber structure and regional deformation following coronary ligation in the rat, and suggests that fibroblast alignment in the direction of greatest stretch provides negative feedback on the level of anisotropy in a scar forming under load. In the future, this coupled model may prove useful in computational design and screening of novel therapies to influence scar formation in mechanically loaded tissues. PMID:25009995

  1. Cytocompatibility and Mechanical Properties of Short Phosphate Glass Fibre Reinforced Polylactic Acid (PLA) Composites: Effect of Coupling Agent Mediated Interface

    PubMed Central

    Hasan, Muhammad Sami; Ahmed, Ifty; Parsons, Andrew; Walker, Gavin; Scotchford, Colin

    2012-01-01

    In this study three chemical agents Amino-propyl-triethoxy-silane (APS), sorbitol ended PLA oligomer (SPLA) and Hexamethylene diisocyanate (HDI) were identified to be used as coupling agents to react with the phosphate glass fibre (PGF) reinforcement and the polylactic acid (PLA) polymer matrix of the composite. Composites were prepared with short chopped strand fibres (l = 20 mm, ? = 20 µm) in a random arrangement within PLA matrix. Improved, initial composite flexural strength (~20 MPa) was observed for APS treated fibres, which was suggested to be due to enhanced bonding between the fibres and polymer matrix. Both APS and HDI treated fibres were suggested to be covalently linked with the PLA matrix. The hydrophobicity induced by these coupling agents (HDI, APS) helped to resist hydrolysis of the interface and thus retained their mechanical properties for an extended period of time as compared to non-treated control. Approximately 70% of initial strength and 65% of initial modulus was retained by HDI treated fibre composites in contrast to the control, where only ~50% of strength and modulus was retained after 28 days of immersion in PBS at 37 °C. All coupling agent treated and control composites demonstrated good cytocompatibility which was comparable to the tissue culture polystyrene (TCP) control, supporting the use of these materials as coupling agent’s within medical implant devices. PMID:24955744

  2. The effects of corn zein protein coupling agent on mechanical properties of flax fiber reinforced composites

    NASA Astrophysics Data System (ADS)

    Whitacre, Ryan John

    In the field of renewable materials, natural fiber composites demonstrate the capacity to be a viable structural material. When normalized by density, flax fiber mechanical properties are competitive with E-glass fibers. However, the hydrophilic nature of flax fibers reduces the interfacial bond strength with polymer thermosets, limiting composite mechanical properties. Corn zein protein was selected as a natural bio-based coupling agent because of its combination of hydrophobic and hydrophilic properties. Zein was deposited on the surface of flax, which was then processed into unidirectional composite. The mechanical properties of zein treated samples where measured and compared against commonly utilized synthetic treatments sodium hydroxide and silane which incorporate harsh chemicals. Fourier transform infrared spectroscopy, chemical analysis, and scanning electron microscopy were also used to determine analyze zein treatments. Results demonstrate the environmentally friendly zein treatment successfully increased tensile strength 8%, flexural strength 17%, and shear strength 30% compared to untreated samples.

  3. The Compatibility Effect Of Coupling Agent On Rheological-Morphological Relationship Of Banana Fibre Reinforced Polypropylene

    SciTech Connect

    Chang, S. Y.; Shamsudin, Z.

    2009-06-01

    The rheological properties of banana fibre reinforced polypropylene (PP/BF) composites at different composition were analysed using Shimadzu capillary rheometer. The effect of coupling agent concentration on the rheological properties was studied and followed by drawing a relationship of rheological-morphological properties of PP/BF composites. It was found that all composite system exhibits pseudoplasticity and incorporation of treated fibres consequents enhanced viscosity due to improved interfacial adhesion at fibre-matrix interface. However, it was observed that PP/BF composite with 2 wt% silane concentration does not yield further enhancement in the rheological properties when compared to that of 1 wt%. Composites with 1 wt% silane concentration were found to yield most promising compatibility effect with well-oriented and uniformly dispersed fibre morphology.

  4. Improved mechanical properties of HDPE/nano-alumina composite through silane coupling agent

    NASA Astrophysics Data System (ADS)

    Akmil, N.; Luqman, C. A.; Ahmad, M.; Zaman, K.

    2012-11-01

    The effect of silane coupling agent to mechanical properties of HDPE/nano-alumina composite was investigated. Nano-alumina used in this study was produced by using sol-gel method. The shape and size of nano-alumina were determined by using TEM. Prior to the usage of nano alumina as a filler in the polymer matrix, (3-methacryloxypropyl) trimethoxysilane (MPS) was used to functionalize the nanoparticles due to its bifunctional nature: hydrolysable group (-Si(OCH3)3) and unsaturated carbon-carbon double bond. The XRD result shows diffraction spectrum of the synthesized nano-alumina. In order to improve the mechanical properties of the composite, nanoalumina was treated with (3-methacryloxypropyl) trimethoxysilane (MPS). A high tensile strength, is achieved at 4 wt% of MPS.

  5. Investigation of oil recovery improvement by coupling an interfacial tension agent and a mobility control agent in light oil reservoirs. Annual report, October 1992--September 1993

    SciTech Connect

    Pitts, M.J.

    1994-06-01

    Investigation of Oil Recovery Improvement by Coupling and Interfacial Tension Agent and a Mobility Control Agent in Light Oil Reservoirs will study two major areas concerning co-injecting an interfacial tension reduction agent(s) and a mobility control agent. The first area defines the interactions of alkaline agent, surfactants, and polymers on a fluid-fluid and fluid-rock basis. The second area concerns the economic improvement of the combined technology. This report examines the interactions of different alkaline agents, surfactants, and polymer combinations on a fluid-fluid basis. Alkali and surfactant combine to reduce the interfacial tension between a low acid number, 42 API gravity crude oil and the aqueous solution to values lower than either agent alone. Surfactant structure can vary from linear chain sulfonates to alkyl aryl sulfonates to produce low interfacial tension values when combined with alkali. However as a class, the alkyl aryl sulfonates were the most effective surfactants. Surfactant olefinic character appears to be critical in developing low interfacial tensions. For the 42 API gravity crude oil, surfactants with molecular weights ranging from 370 to 450 amu are more effective in lowering interfacial tension. Ultra low interfacial tensions were achieved with all of the alkaline agents evaluated when combined with appropriate surfactants. Different interfacial tension reduction characteristics with the various alkali types indicates alkali interacts synergistically with the surfactants to develop interfacial tension reduction. The solution pH is not a determining factor in lowering interfacial tension. Surfactant is the dominant agent for interfacial tension reduction.

  6. Effects of the methyltrimethoxysilane coupling agent on phenolic and miscanthus composites containing calcium sulfite scrubber material

    NASA Astrophysics Data System (ADS)

    Jones, Sean

    The purpose of this research is to test the effects of methyltrimethoxysilane coupling agent on composite material containing calcium sulfite obtained from the Southern Illinois Power Co-operative. This scrubber material and the miscanthus plant are of interest due to their use in coal burning power plants to reduce toxic emission. When calcium sulfate is passed through coal fire gas emissions it absorbs mercury and sulfur. In these composites it is used as filler to reduce cost. Miscanthus is a source of both cellulose reinforcement and some natural resin. This plant has low care requirements, little mineral content, useful energy return, and positive environmental effects. Under investigation is whether a post-cure procedure or a silane coupling agent will positively impact the composite. Hot pressing alone may not be enough to fully cure the phenolic. It is hoped that the silane will increase the strength characteristics of the composite by enhancing adhesion between the calcium sulfite and phenolic resin. Possible effects on the miscanthus by the silane will also be tested. Phenolic is being utilized because of its recycling and biodegradable properties along with cost effectiveness in mass production. Composite mechanical performance was measured through 3-point bending to measure flexural strength and strain at breakage. A dynamic mechanical analyzer (DMA) was used to find thermomechanical properties. The post-cure was found to be effective, particularly on the final composite containing silane. When methyltrimethoxysilane was added to the miscanthus prior to fabrication, it was found to reduce flexural strength and density. However the addition of methyltrimethoxysilane to the calcium sulfite altered thermo-mechanical properties to a state more like pure phenolic, with added flexibility and thermal stability.

  7. Facile Synthesis of Reductively Degradable Biopolymers Using Cystamine Diisocyanate as a Coupling Agent.

    PubMed

    Wang, Xiuxiu; Zhang, Jian; Cheng, Ru; Meng, Fenghua; Deng, Chao; Zhong, Zhiyuan

    2016-03-14

    Reductively degradable biopolymers have emerged as a unique class of smart biomedical materials. Here, a functional coupling agent, cystamine diisocyanate (CDI), was designed to offer a facile access to reductively degradable biopolymers via polycondensation with various diols. CDI was readily obtained with a decent yield of 46% by reacting cystamine dihydrochloride with triphosgene. The polycondensation of oligo(ethylene glycol) diol (Mn = 0.4 or 1.5 kg/mol) or oligo(ε-caprolactone) diol (Mn = 0.53 kg/mol) with CDI in N,N-dimethylformamide at 60 °C using dibutyltin dilaurate as a catalyst afforded reductively degradable poly(ethylene glycol) (SSPEG, Mn = 6.2-76.8 kg/mol) or poly(ε-caprolactone) (SSPCL, Mn = 6.8-16.3 kg/mol), in which molecular weights were well controlled by diol/CDI molar ratios. Moreover, PEG-SSPCL-PEG triblock copolymers could be readily prepared by reacting dihydroxyl-terminated SSPCL with PEG-isocyanate derivative. PEG-SSPCL-PEG with an Mn of 5.0-16.3-5.0 kg/mol formed small-sized micelles with an average diameter of about 85 nm in PB buffer. The in vitro release studies using doxorubicin (DOX) as a model drug showed that, in sharp contrast to reduction-insensitive PEG-PCL(HDI)-PEG controls, drug release from PEG-SSPCL-PEG micelles was fast and nearly complete in 24 h under a reductive condition containing 10 mM glutathione. The confocal microscopy experiments in drug-resistant MCF-7 cells (MCF-7/ADR) displayed efficient cytoplasmic DOX release from PEG-SSPCL-PEG micelles. MTT assays revealed that DOX-loaded PEG-SSPCL-PEG micelles were much more potent against MCF-7/ADR cells than reduction-insensitive PEG-PCL(HDI)-PEG controls (IC50: 6.3 vs 55.4 μg/mL). It should further be noted that blank PEG-SSPCL-PEG micelles were noncytotoxic up to a tested concentration of 1 mg/mL. Hence, cystamine diisocyanate appears to be an innovative coupling agent that facilitates versatile synthesis of biocompatible and reductively degradable biopolymers. PMID:26810050

  8. The effect of interstitial pressure on therapeutic agent transport: coupling with the tumor blood and lymphatic vascular systems.

    PubMed

    Wu, Min; Frieboes, Hermann B; Chaplain, Mark A J; McDougall, Steven R; Cristini, Vittorio; Lowengrub, John S

    2014-08-21

    Vascularized tumor growth is characterized by both abnormal interstitial fluid flow and the associated interstitial fluid pressure (IFP). Here, we study the effect that these conditions have on the transport of therapeutic agents during chemotherapy. We apply our recently developed vascular tumor growth model which couples a continuous growth component with a discrete angiogenesis model to show that hypertensive IFP is a physical barrier that may hinder vascular extravasation of agents through transvascular fluid flux convection, which drives the agents away from the tumor. This result is consistent with previous work using simpler models without blood flow or lymphatic drainage. We consider the vascular/interstitial/lymphatic fluid dynamics to show that tumors with larger lymphatic resistance increase the agent concentration more rapidly while also experiencing faster washout. In contrast, tumors with smaller lymphatic resistance accumulate less agents but are able to retain them for a longer time. The agent availability (area-under-the curve, or AUC) increases for less permeable agents as lymphatic resistance increases, and correspondingly decreases for more permeable agents. We also investigate the effect of vascular pathologies on agent transport. We show that elevated vascular hydraulic conductivity contributes to the highest AUC when the agent is less permeable, but to lower AUC when the agent is more permeable. We find that elevated interstitial hydraulic conductivity contributes to low AUC in general regardless of the transvascular agent transport capability. We also couple the agent transport with the tumor dynamics to simulate chemotherapy with the same vascularized tumor under different vascular pathologies. We show that tumors with an elevated interstitial hydraulic conductivity alone require the strongest dosage to shrink. We further show that tumors with elevated vascular hydraulic conductivity are more hypoxic during therapy and that the response slows down as the tumor shrinks due to the heterogeneity and low concentration of agents in the tumor interior compared with the cases where other pathological effects may combine to flatten the IFP and thus reduce the heterogeneity. We conclude that dual normalizations of the micronevironment - both the vasculature and the interstitium - are needed to maximize the effects of chemotherapy, while normalization of only one of these may be insufficient to overcome the physical resistance and may thus lead to sub-optimal outcomes. PMID:24751927

  9. Agents.

    PubMed

    Chambers, David W

    2002-01-01

    Although health care is inherently an economic activity, it is inadequately described as a market process. An alternative, grounded in organizational economic theory, is to view professionals and many others as agents, contracted to advance the best interests of their principals (patients). This view untangles some of the ethical conflicts in dentistry. It also helps identify major controllable costs in dentistry and suggests that dentists can act as a group to increase or decrease agency costs, primarily by controlling the bad actors who damage the value of all dentists. PMID:12132261

  10. Socio-Ecohydrologic Agents And Services: Integrating Human And Natural Components To Address Coupled System Resilience

    NASA Astrophysics Data System (ADS)

    Pavao-zuckerman, M.; Pope, A.; Chan, D.; Curl, K.; Gimblett, H. R.; Hough, M.; House-Peters, L.; Lee, R.; Scott, C. A.

    2012-12-01

    Riparian corridors in arid regions are highly valued for their relative scarcity, and because healthy riparian systems support high levels of biodiversity, can meet human demand for water and water-related resources and functions. Our team is taking a transdiciplinary social-ecological systems approach to assessing riparian corridor resilience in two watersheds (the San Pedro River in USA and Mexico, and the Rio San Miguel in Mexico) through a project funded by the NSF CNH program ("Strengthening Resilience of Arid Region Riparian Corridors"). Multiple perspectives are integrated in the project, including hydrology, ecology, institutional dynamics, and decision making (at the level of both policy and individual choice), as well as the perspectives of various stakeholder groups and individuals in the watersheds. Here we discuss initial findings that center around linking changes in ecohydrology and livelihoods related to decisions in response to climatic, ecological, and social change. The research team is implementing two approaches to integrate the disparate disciplines participating in the research (and the varied perspectives among the stakeholders in this binational riparian context): (1) ecosystem service assessment, and (2) agent based model simulation. We are developing an ecosystem service perspective that provides a bridge between ecological dynamics in the landscape and varied stakeholder perspectives on the implications of ecohydrology for well-being (economic, cultural, ecological). Services are linked on one hand to the spatial patterns of traits of individuals within species (allowing a more predictive application of ecosystem services as they vary with community change in time), and to stakeholder perspectives (facilitating integration of ecosystem services into our understanding of decision making processes) in a case study in the San Pedro River National Conservation Area. The agent- based model (ABM) approach incorporates the influence of human decision-making on spatially-explicit landscapes in a mechanistic way, taking into account social interaction, adaptation, and decision-making at different levels, allowing individual stakeholders to make decisions based on their unique perceptions of their environment, be it economic, social, or ecological awareness. Initial parameterization of the ABM proceeds from a case study centered in the town of Rayón, Sonora, Mexico, where semi-structured interviews were used to elicit perceptions by water resource users of CNH function, change, and solutions relating to livelihood changes in response to several drivers. In both case studies, we see the potential and limitations for an approach to adaptive management and decision support related to water resources that links ecosystem services and agent-based modeling. Methodologically, synthetic approaches such as these may allow coupling of systems for improved assessment and analysis, while at the same time lack a connection to the perspectives of water users and managers on the ground. There is thus potential for a either a loss of system resilience in the face of external change, or an opportunity to increase system resilience by building off perspectives already in place within these coupled socio-ecohydrologic systems.

  11. Influence of silane coupling agents on the rheological behavior of hemp fiber filled polyamide 1010 biomass composites in molten state

    NASA Astrophysics Data System (ADS)

    Nishitani, Yosuke; Hasumi, Megumi; Kitano, Takeshi

    2015-05-01

    In order to develop the new engineering materials such as structural materials and tribomaterials based on all plants-derived materials, the influence of silane coupling agent on the rheological properties of hemp fiber (HF) filled polyamide 1010 (PA1010) biomass composites in molten state was investigated for one step of the fabrication of these materials. PA1010 was made from sebacic acid and decamethylenediamine, which are obtained from plant-derived castor oil. Hemp fibers were surface-treated by two types of surface treatment: a) alkali treatment by NaOH solution and b) surface treatment by silane coupling agents with different concentrations. Three types of silane coupling agents: aminosilane, epoxysilane and ureidosilane were used for surface treatment. HF/PA1010 composites were extruded by a twin screw extruder and compression-molded. Rheological behavior in molten state were evaluated by oscillatory flow testing using a parallel plate type rheometer. It was found that the silane coupling agents remarkably influence on: 1) rheological properties such as storage modulus, loss modulus, loss tangent and complex viscosity in low angular frequency region in molten state, 2) temperature dependences of rheological properties, and 3) relationship between phase angle and complex modulus (van Gurp - Palmen plots). These rheological behavior were also strongly influenced by the type of silane coupling agents. The viscoelastic properties (both storage and loss moduli) of aminosilane and epoxysilane treated composites were lower, however, those of ureidosilane treated ones were higher than the moduli of only alkali treated composites. Ureidosilane treated composites were the least temperature sensitive in the surface treated composites investigated here.

  12. Investigation of oil recovery improvement by coupling an interfacial tension agent and a mobility control agent in light oil reservoirs. Second annual report, October 1993--September 1994

    SciTech Connect

    Pitts, M.J.

    1995-04-01

    {open_quotes}Investigation of Oil Recovery Improvement by Coupling an Interfacial Tension Agent and a Mobility Control Agent in Light Oil Reservoirs{close_quotes} is studying two major areas concerning co-injecting an interfacial tension reduction agent(s) and a mobility control agent. The first area defines the interactions of alkaline agents, surfactants, and polymers on a fluid-fluid and a fluid-rock basis. The second area concerns the economic improvement of the combined technology. This report continues the fluid-fluid interaction evaluations and begins the fluid-rock studies. Fluid-fluid interfacial tension work determined that replacing sodium ion with either potassium or ammonium ion in solutions with interfacial tension reduction up to 19,600 fold was detrimental and had little or no effect on alkali-surfactant solutions with interfacial tension reduction of 100 to 200 fold. Reservoir brine increases interfacial tension between crude oil and alkaline-surfactant solutions. Na{sub 2}CO{sub 3}-surfactant solutions maintained ultra low and low interfacial tension values better than NaOH-surfactant solutions. The initial phase of the fluid-rock investigations was adsorption studies. Surfactant adsorption is reduced when co-dissolved with alkali. Na{sub 2}CO{sub 3} and Na{sub 3}PO{sub 4} are more efficient at reducing surfactant adsorption than NaOH. When polymer is added to the surfactant solution, surfactant adsorption is reduced as well. When both polymer and alkali are added, polymer is the dominate component, reducing the Na{sub 2}CO{sub 3} and NaOH effect on adsorption. Substituting sodium ion with potassium or ammonium ion increased or decreased surfactant adsorption depending on surfactant structure with alkali having a less significant effect. No consistent change of surfactant adsorption with increasing salinity was observed in the presence or absence of alkali or polymer.

  13. Highly Efficient Arsenic Removal Using a Composite of Ultrafine Magnetite Nanoparticles Interlinked by Silane Coupling Agents

    PubMed Central

    Chang, Shu-Chi; Yu, Yu-Han; Li, Cheng-Hao; Wu, Chin-Ching; Lei, Hao-Yun

    2012-01-01

    Arsenic (As) contamination in groundwater is a great environmental health concern and is often the result of contact between groundwater and arsenic-containing rocks or sediments and from variation of pH and redox potentials in the subsurface. In the past decade, magnetite nanoparticles (MNPs) have been shown to have high adsorption activity towards As. Alerted by the reported cytotoxicity of 5–12 nm MNP, we studied the adsorption behavior of 1.15 nm MNP and a MNP composite (MNPC), MNPs interlinked by silane coupling agents. With an initial concentration of As at 25 mg L−1, MNPs exhibited high adsorption capacity for As(V) and As (III), 206.9 mg·g−1 and 168.6 mg·g−1 under anaerobic conditions, respectively, and 109.9 mg·g−1 and 108.6 mg·g−1 under aerobic conditions, respectively. Under aerobic conditions, MNPC achieved even higher adsorption capacity than MNP, 165.1 mg·g−1 on As(V) and 157.9 mg·g−1 on As(III). For As(V) at 50 mg L−1, MNPC achieved an adsorption capacity as high as 341.8 mg·g−1, the highest in the literature. A kinetic study indicated that this adsorption reaction can reach equilibrium within 15 min and the rate constant of As(V) is about 1.9 times higher than that of As(III). These results suggested that MNPC can serve as a highly effective adsorbent for fast removal of As. PMID:23202769

  14. Attaching biological probes to silica optical biosensors using silane coupling agents.

    PubMed

    Soteropulos, Carol E; Hunt, Heather K

    2012-01-01

    In order to interface with biological environments, biosensor platforms, such as the popular Biacore system (based on the Surface Plasmon Resonance (SPR) technique), make use of various surface modification techniques, that can, for example, prevent surface fouling, tune the hydrophobicity/hydrophilicity of the surface, adapt to a variety of electronic environments, and most frequently, induce specificity towards a target of interest. These techniques extend the functionality of otherwise highly sensitive biosensors to real-world applications in complex environments, such as blood, urine, and wastewater analysis. While commercial biosensing platforms, such as Biacore, have well-understood, standard techniques for performing such surface modifications, these techniques have not been translated in a standardized fashion to other label-free biosensing platforms, such as Whispering Gallery Mode (WGM) optical resonators. WGM optical resonators represent a promising technology for performing label-free detection of a wide variety of species at ultra-low concentrations. The high sensitivity of these platforms is a result of their unique geometric optics: WGM optical resonators confine circulating light at specific, integral resonance frequencies. Like the SPR platforms, the optical field is not totally confined to the sensor device, but evanesces; this "evanescent tail" can then interact with species in the surrounding environment. This interaction causes the effective refractive index of the optical field to change, resulting in a slight, but detectable, shift in the resonance frequency of the device. Because the optical field circulates, it can interact many times with the environment, resulting in an inherent amplification of the signal, and very high sensitivities to minor changes in the environment. To perform targeted detection in complex environments, these platforms must be paired with a probe molecule (usually one half of a binding pair, e.g. antibodies/antigens) through surface modification. Although WGM optical resonators can be fabricated in several geometries from a variety of material systems, the silica microsphere is the most common. These microspheres are generally fabricated on the end of an optical fiber, which provides a "stem" by which the microspheres can be handled during functionalization and detection experiments. Silica surface chemistries may be applied to attach probe molecules to their surfaces; however, traditional techniques generated for planar substrates are often not adequate for these three-dimensional structures, as any changes to the surface of the microspheres (dust, contamination, surface defects, and uneven coatings) can have severe, negative consequences on their detection capabilities. Here, we demonstrate a facile approach for the surface functionalization of silica microsphere WGM optical resonators using silane coupling agents to bridge the inorganic surface and the biological environment, by attaching biotin to the silica surface. Although we use silica microsphere WGM resonators as the sensor system in this report, the protocols are general and can be used to functionalize the surface of any silica device with biotin. PMID:22588224

  15. Coupling multi-agent model and GIS to simulate pine wood nematode disease spread in ZheJiang Province, China

    NASA Astrophysics Data System (ADS)

    Huang, Huaguo; Wang, Lei; Zhang, XiaoLi; Luo, YouQing; Zhao, Liqiong

    2008-10-01

    A coupled method based on multi-agent model, remote sensing and GIS is described to simulate the forest disease spread. The coupled model focuses on the temporal dynamics of the Bursaphelenchus xylophilus population at the landscape scale. Each individual is modeled as an autonomous agent who behaves according to a set of rules including spreading in the landscape, feeding on Pinus massoniana, sheltering in forest edges and dying, constrained by terrain, land cover and other variables. The model parameters are derived from remote sensing data and field measurements. Ten factors, including damage degree of Pinus Massoniana, altitude and slope, are helped to build the transfer rules. The main outputs are the dynamic disease distribution maps and survived pine population. Our method is applied and validated in DingHai distinct, Zhou Shan city of Zhejiang Province. Three Landsat TM images from the year 1991 to 2006 are used for the pine information extraction. The extracted pine distribution map is used to compare with the simulated surviving pine map. The results show that the coupled model can produce reasonable results and be used as a virtual experiment tool. However, it is difficult to simulate the human activities to help or prevent disease spread and the long fly behavior of insect vectors. Therefore, there still exists some difference between the simulated results and the real data. At the next step, those factors will be considered.

  16. Mechanical and dynamic characteristics of encapsulated microbubbles coupled by magnetic nanoparticles as multifunctional imaging and drug delivery agents.

    PubMed

    Guo, Gepu; Lu, Lu; Yin, Leilei; Tu, Juan; Guo, Xiasheng; Wu, Junru; Xu, Di; Zhang, Dong

    2014-11-21

    Development of magnetic encapsulated microbubble agents that can integrate multiple diagnostic and therapeutic functions is a key focus in both biomedical engineering and nanotechnology and one which will have far-reaching impact on medical diagnosis and therapies. However, properly designing multifunctional agents that can satisfy particular diagnostic/therapeutic requirements has been recognized as rather challenging, because there is a lack of comprehensive understanding of how the integration of magnetic nanoparticles to microbubble encapsulating shells affects their mechanical properties and dynamic performance in ultrasound imaging and drug delivery. Here, a multifunctional imaging contrast and in-situ gene/drug delivery agent was synthesized by coupling super paramagnetic iron oxide nanoparticles (SPIOs) into albumin-shelled microbubbles. Systematical studies were performed to investigate the SPIO-concentration-dependence of microbubble mechanical properties, acoustic scattering response, inertial cavitation activity and ultrasound-facilitated gene transfection effect. These demonstrated that, with the increasing SPIO concentration, the microbubble mean diameter and shell stiffness increased and ultrasound scattering response and inertial cavitation activity could be significantly enhanced. However, an optimized ultrasound-facilitated vascular endothelial growth factor transfection outcome would be achieved by adopting magnetic albumin-shelled microbubbles with an appropriate SPIO concentration of 114.7 µg ml(-1). The current results would provide helpful guidance for future development of multifunctional agents and further optimization of their diagnostic/therapeutic performance in clinic. PMID:25327566

  17. Mechanical and dynamic characteristics of encapsulated microbubbles coupled by magnetic nanoparticles as multifunctional imaging and drug delivery agents

    NASA Astrophysics Data System (ADS)

    Guo, Gepu; Lu, Lu; Yin, Leilei; Tu, Juan; Guo, Xiasheng; Wu, Junru; Xu, Di; Zhang, Dong

    2014-11-01

    Development of magnetic encapsulated microbubble agents that can integrate multiple diagnostic and therapeutic functions is a key focus in both biomedical engineering and nanotechnology and one which will have far-reaching impact on medical diagnosis and therapies. However, properly designing multifunctional agents that can satisfy particular diagnostic/therapeutic requirements has been recognized as rather challenging, because there is a lack of comprehensive understanding of how the integration of magnetic nanoparticles to microbubble encapsulating shells affects their mechanical properties and dynamic performance in ultrasound imaging and drug delivery. Here, a multifunctional imaging contrast and in-situ gene/drug delivery agent was synthesized by coupling super paramagnetic iron oxide nanoparticles (SPIOs) into albumin-shelled microbubbles. Systematical studies were performed to investigate the SPIO-concentration-dependence of microbubble mechanical properties, acoustic scattering response, inertial cavitation activity and ultrasound-facilitated gene transfection effect. These demonstrated that, with the increasing SPIO concentration, the microbubble mean diameter and shell stiffness increased and ultrasound scattering response and inertial cavitation activity could be significantly enhanced. However, an optimized ultrasound-facilitated vascular endothelial growth factor transfection outcome would be achieved by adopting magnetic albumin-shelled microbubbles with an appropriate SPIO concentration of 114.7 µg ml-1. The current results would provide helpful guidance for future development of multifunctional agents and further optimization of their diagnostic/therapeutic performance in clinic.

  18. Photocatalytic thin films coupled with polymeric microcapsules for the controlled-release of volatile agents upon solar activation

    NASA Astrophysics Data System (ADS)

    Oliveira, L. F.; Marques, J.; Coutinho, P. J. G.; Parpot, P.; Tavares, C. J.

    2013-06-01

    This work reportson the application of solar-activated photocatalytic thin films that allow the controlled-release of volatile agents (e.g., insecticides, repellents) from the interior of adsorbedpolymericmicrocapsules. In order to standardize the tests, a quantification of the inherent controlled-release of a particular volatile agent is determined by gas chromatography coupled to mass spectroscopy, so that an application can be offered to a wide range of supports from various industrial sectors, such as in textiles (clothing, curtains, mosquito nets). This technology takes advantage of the established photocatalytic property of titanium dioxide (TiO2) for the use as an active surface/site to promote the controlled-release of a specific vapor (volatile agentfrom within the aforementioned microcapsules.

  19. Effect of coupling agent on nano-ZnO modification and antibacterial activity of ZnO/HDPE nanocomposite films

    NASA Astrophysics Data System (ADS)

    Li, Y. N.; Xu, W. M.; Zhang, G. Q.

    2015-07-01

    Commercial zinc oxide nanoparticles were modified by silane coupling agent of KH550 and KH560, respectively. The obtained nanocomposite was characterized by scanning electron microscopy (SEM), Thermogravimetric analyses (TGA) and apparent sedimentation stability (Sapp). Then, nano-ZnO/high-density polyethylene (HDPE) composite films were prepared via melt blending and a hot compression-molding process. The antibacterial testing of the films against E. coli and S. aureus was carried out via plate counting. SEM, TGA and Sapp suggest the modifier of silane changed the surface hydrophilicity and effectively broke the agglomerations of nanoparticles. Antibacterial testing results indicated the antibacterial rate of the films increased with increasing nano-ZnO content. At a low doped content of 0.2 wt%, the types of coupling agent influenced the antibacterial property with that of KH560-modified nano-ZnO/HDPE KH550-modified nano-ZnO/HDPE unmodified nano-ZnO/HDPE films. When the dosage nano-ZnO was over 0.2 wt%, the differences of antibacterial activity resulted by modification was concealed by the strong antibacterial activity with near 100% of the nano- ZnO/HDPE composite films.

  20. Investigation of oil recovery improvement by coupling an interfacial tension agent and a mobility control agent in light oil reservoirs. Final report

    SciTech Connect

    Pitts, M.

    1995-12-01

    This research studied the oil recovery potential of flooding light oil reservoirs by combining interfacial tension reducing agent(s) with a mobility control agent. The specific objectives were: To define the mechanisms and limitations of co-injecting interfacial tension reduction agent(s) and a mobility control agent to recover incremental oil. Specifically, the study focused on the fluid-fluid and fluid-rock interactions. To evaluate the economics of the combination technology and investigate methods to make the process more profitable. Specific areas of study were to evaluate different chemical concentration tapers and the volume of chemical injection required to give optimal oil recovery.

  1. Investigation of oil recovery improvement by coupling an interfacial tension agent and a mobility control agent in light oil reservoirs. Technical progress report, September--December 1993

    SciTech Connect

    Pitts, M.J.

    1993-12-31

    The study will investigate two major areas concerning co-injecting an interfacial tension reduction agent(s) and a mobility control agent into petroleum reservoirs. The first will consist of defining the mechanisms of interaction of an alkaline agent, a surfactant, and a polymer on a fluid-fluid and a fluid-rock basis. The second is the improvement of the economics of the combined technology. This report examines the adsorption of alkali, surfactant, and polymer onto crushed Berea sandstone.

  2. Unique Separation Behavior of a C60 Fullerene-Bonded Silica Monolith Prepared by an Effective Thermal Coupling Agent.

    PubMed

    Kubo, Takuya; Murakami, Yoshiki; Tsuzuki, Madoka; Kobayashi, Hiroshi; Naito, Toyohiro; Sano, Tomoharu; Yan, Mingdi; Otsuka, Koji

    2015-12-01

    Herein, we report a newly developed C60 fullerene-bonded silica monolith in a capillary with unique retention behavior due to the structure of C60 fullerene. N-Hydroxysuccinimide (NHS)-conjugated C60 fullerene was successfully synthesized by a thermal coupling agent, perfluorophenyl azide (PFPA), and assigned by spectroscopic analyses. Then, NHS-PFPA-C60 fullerene was attached onto the surface of a silica monolith in a capillary. The capillary provided specific separation ability for polycyclic aromatic hydrocarbons in liquid chromatography by an effective π-π interaction. Furthermore, corannulene, which has a hemispherical structure, was selectively retained in the capillary based on the specific structural recognition due to the spherical C60 fullerene. This is the first report revealing the spherical recognition ability by C60 fullerene in liquid chromatographic separation. PMID:26493764

  3. Rapid recovery of DNA from agarose gel slices by coupling electroelution with monolithic SPE.

    PubMed

    Yu, Shengbing; Yang, Shuixian; Zhou, Ping; Zhou, Ke; Wang, Jing; Chen, Xiangdong

    2009-06-01

    An amino silica monolithic column prepared by in situ polymerization of tetraethoxysilane and N-(beta-aminoethyl)-gamma-aminopropyltriethoxysilane was firstly applied to recover DNA from agarose gel slices by coupling electroelution with monolithic SPE. DNA was electroeluted from the agarose gel slices onto the amino silica monolithic column. The DNA adsorbed on this monolithic column was then recovered using sodium phosphate solution at pH 10. The whole recovery procedure could be completed within 10 min because the use of amino silica monolithic column accelerated the DNA capture and facilitated the DNA release. Electroelution conditions, such as buffer pH, buffer concentration and applied voltage, were online optimized. The average yield for herring sperm DNA, pBR 322 DNA and lambda DNA recovered from 1.0% w/v agarose gel slices were 55+/-4, 50+/-6 and 42+/-7% (n=3), respectively. The polymerase chain reaction performance of pGM plasmid recovered from agarose gel slices demonstrated that the method could provide high-quality DNA for downstream processes. The combination of electroelution with monolithic SPE allows a rapid, simple and efficient DNA recovery method. This technique is especially useful for applications that need to purify small starting amounts of DNA. PMID:19582711

  4. Investigation of oil recovery improvement by coupling an interfacial tension agent and a mobility control agent in light oil reservoirs. Technical progress report, April--June 1993

    SciTech Connect

    Pitts, M.J.

    1993-10-01

    The study will investigate two major areas concerning co-injecting on interfacial tension reduction agent(s) and a mobility control agent into petroleum reservoirs. The first will consist of defining the mechanisms of interaction of an alkaline agent, a surfactant, and a polymer on a fluid-fluid and fluid-rock basis. The second is the improvement of the economic of the combined technology. This report examines the effect of polymer addition to different combinations of alkaline agents and surfactants. Xanthan gum and polyacrylamide polymers were evaluated. In addition, the effect of alkali and polymer on the critical micelle concentration of different surfactant types was investigated.

  5. Investigation of oil recovery improvement by coupling an interfacial tension agent and a mobility control agent in light oil reservoirs. Technical progress report, July--September 1993

    SciTech Connect

    Pitts, M.J.

    1993-12-01

    The study will investigate two major areas concerning co-injecting an interfacial tension reduction agent(s) and a mobility control agent into petroleum reservoirs. The first will consist of defining the mechanisms of interaction of an alkaline agent, a surfactant, and a polymer on a fluid-fluid and a fluid-rock basis. The second is the improvement of the economics of the combined technology. This report examines the effect of polymer addition to different combinations of alkaline agents and surfactants. Xanthan gum and polyacrylamide polymers were evaluated. In addition, the effect of alkali and polymer on the critical micelle concentration of different surfactant types was investigated.

  6. A Multiplex PCR-coupled Liquid Bead Array for the Simultaneous Detection of Four Biothreat Agents

    SciTech Connect

    Wilson, W J; Erler, A M; Nasarabadi, S L; Skowronski, E W; McCready, P M

    2004-02-04

    We have developed a 10-plexed PCR assay coupled to a 12-plexed liquid bead array to rapidly screen environmental samples for B. anthracis, Y. pestis, F. tularensis, and B. melitensis. Highly validated species -specific primer sets were used to simultaneously amplify multiple diagnostic regions unique to each individual pathogen. Resolution of the mix of amplified products was achieved by PCR product hybridization to corresponding probe sequences, attached to unique sets of fluorescent beads. The hybridized beads were processed through a flow cytometer, which detected presence and quantity of each PCR product. The assay was optimized to allow for maximum sensitivity in a multiplexed format. A high- throughput demonstration was performed where 384 simulated environmental samples were spiked with different amounts of B. thuringensis spores and pathogen DNA. The samples were robotically processed to extract DNA and arrayed for multiplexed PCR-liquid bead detection. The assay correctly identified the presence or absence of each pathogen and collected over 3,000 individual data points within a single 8-hour shift for approximately $1.20 per sample in a 10-plexed assay.

  7. Understanding coupled natural and human systems on fire prone landscapes: integrating wildfire simulation into an agent based planning system.

    NASA Astrophysics Data System (ADS)

    Barros, Ana; Ager, Alan; Preisler, Haiganoush; Day, Michelle; Spies, Tom; Bolte, John

    2015-04-01

    Agent-based models (ABM) allow users to examine the long-term effects of agent decisions in complex systems where multiple agents and processes interact. This framework has potential application to study the dynamics of coupled natural and human systems where multiple stimuli determine trajectories over both space and time. We used Envision, a landscape based ABM, to analyze long-term wildfire dynamics in a heterogeneous, multi-owner landscape in Oregon, USA. Landscape dynamics are affected by land management policies, actors decisions, and autonomous processes such as vegetation succession, wildfire, or at a broader scale, climate change. Key questions include: 1) How are landscape dynamics influenced by policies and institutions, and 2) How do land management policies and actor decisions interact to produce intended and unintended consequences with respect to wildfire on fire-prone landscapes. Applying Envision to address these questions required the development of a wildfire module that could accurately simulate wildfires on the heterogeneous landscapes within the study area in terms of replicating historical fire size distribution, spatial distribution and fire intensity. In this paper we describe the development and testing of a mechanistic fire simulation system within Envision and application of the model on a 3.2 million fire prone landscape in central Oregon USA. The core fire spread equations use the Minimum Travel Time algorithm developed by M Finney. The model operates on a daily time step and uses a fire prediction system based on the relationship between energy release component and historical fires. Specifically, daily wildfire probabilities and sizes are generated from statistical analyses of historical fires in relation to daily ERC values. The MTT was coupled with the vegetation dynamics module in Envision to allow communication between the respective subsystem and effectively model fire effects and vegetation dynamics after a wildfire. Canopy and surface fuels are modeled in a state and transition framework that accounts for succession, fire effects, and fuels management. Fire effects are modeled using simulated fire intensity (flame length) to calculate expected vegetation impacts for each vegetation state. This talk will describe the mechanics of the simulation system along with initial results of Envision simulations for the Central Oregon study area that explore the dynamics of wildfire, fuel management, and succession over time.

  8. Investigation of oil recovery improvement by coupling an interfacial tension agent and a mobility control agent in light oil reservoirs. Technical progress report, October--December 1994

    SciTech Connect

    Pitts, M.J.

    1994-01-01

    The study will investigate two major areas concerning co-injecting an interfacial tension reduction agent(s) and a mobility control agent into petroleum reservoirs. The first will consist of defining the mechanisms of interaction of an alkaline agent, a surfactant, and a polymer on a fluid-fluid and a fluid-rock basis. The second is the improvement of the economics of the combined technology. This report examines effect of rock type on oil recovery by an alkaline-surfactant-polymer solutions. This report also begins a series of evaluations to improve the economics of alkaline-surfactant-polymer oil recovery.

  9. Investigation of oil recovery improvement by coupling an interfacial tension agent and a mobility control agent in light oil reservoirs. Technical progress report, July 1995--September 1995

    SciTech Connect

    Pitts, M.J.

    1995-10-01

    This study will investigate two major areas concerning co-injection and interfacial tension reduction agents and a mobility control agent into petroleum reservoirs. The first will consist of defining the mechanisms of interaction of an alkaline agent, a surfactant, and a polymer on a fluid-fluid and a fluid-rock basis. The second is the improvement of the economics of the combined technology. This report examines altering the concentration of alkali and polymer on the oil recovery economics of alkaline-surfactant-polymer solution.

  10. Exfoliated graphite nanoplatelet-filled impact modified polypropylene nanocomposites: influence of particle diameter, filler loading, and coupling agent on the mechanical properties

    NASA Astrophysics Data System (ADS)

    Duguay, Alex J.; Nader, Jacques W.; Kiziltas, Alper; Gardner, Douglas J.; Dagher, Habib J.

    2014-03-01

    Exfoliated graphite nanoplatelets (xGnP)-filled impact-modified polypropylene (IMPP) composites were prepared at 2, 4, 6, and 8 wt % xGnP with and without the addition of a coupling agent and manufactured using melt mixing followed by injection molding. The coupling agent used in this study was polypropylene-graft-maleic anhydride (PP-g-MA). The nanoparticles used were xGnP with three different sizes: xGnP5 has an average thickness of 10 nm, and an average platelet diameter of 5 ?m, whereas xGnP15 and xGnP25 have the same thickness but average diameters are 15 and 25 ?m, respectively. Test results show that nanocomposites with smaller xGnP diameter exhibited better flexural and tensile properties for both neat and compatibilized composites. For composites containing a coupling agent, tensile and flexural modulus and strength increased with the addition of xGnP. In the case of neat composites, both tensile and flexural modulus and strength decreased at higher filler loading levels. Increasing xGnP loading resulted in reduction of elongation at break for both neat and composites containing coupling agent. Explanation of this brittle behavior in a nanoplatelet-filled IMPP is presented using scanning electron microscopy and transmission electron microscopy.

  11. Investigation of oil recovery improvement by coupling an interfacial tension agent and a mobility control agent in light oil reservoirs. Technical progress report, April--June 1994

    SciTech Connect

    Pitts, M.J.; Casteel, J.

    1994-09-01

    The study will investigate two major areas concerning co-injecting an interfacial tension reduction agent(s) and a mobility control agent into petroleum reservoirs. The first will consist of defining the mechanisms of interaction of an alkaline agent, a surfactant, and a polymer on a fluid-fluid and a fluid-rock basis. The second is the improvement of the economics of the combined technology. This report examines the changes in the relative permeability characteristics with addition of alkali, surfactant, and polymer to the injected solution, the effect of matrix type on relative permeability characteristics with alkali-surfactant-polymer and the effect of different polymer concentrations on oil recovery by an alkaline-surfactant-polymer solution.

  12. Surface modification of pyrophyllite with amino silane coupling agent for the removal of 4-nitrophenol from aqueous solutions.

    PubMed

    Sayilkan, H; Erdemo?lu, S; Sener, S; Sayilkan, F; Akarsu, M; Erdemo?lu, M

    2004-07-15

    The surface of naturally hydrophobic mineral pyrophyllite was modified to hydrophilic by treatment with prehydrolyzed N-(2-aminoethyl)-3-aminopropyltrimethoxysilane (APEO) coupling agent to prepare a novel and effective adsorbent for the removal of 4-nitrophenol (4-NP) from aqueous solutions. XRD, FTIR, and SEM analyses were used to characterize the surface modification. It was found that after the grafting procedure, heat treatment at 110 degrees C results in condensation reaction between the OH groups of the APEO molecule and the hydroxyl groups and/or oxygen atoms on the pyrophyllite surface and the adsorption of 4-NP by APEO-modified pyrophyllite involves interactions between dissociated 4-NP molecules and protonated amine groups of APEO molecules attached to the mineral surface. Adsorption equilibrium data for 4-NP adsorption on APEO-treated and untreated pyrophyllite were most satisfactorily fitted using the Freundlich adsorption isotherm and adsorption capacity was found to be 0.268 mg/g for modified pyrophyllite whereas it was only 0.105 mg/g for untreated pyrophyllite. PMID:15178283

  13. A high efficient method for introducing reactive amines onto carbon fiber surfaces using hexachlorocyclophosphazene as a new coupling agent

    NASA Astrophysics Data System (ADS)

    Xu, Haibing; Zhang, Xiaoqing; Liu, Dong; Chun, Yan; Fan, Xinyu

    2014-11-01

    To improve the interfacial properties of carbon fiber (CF) reinforced composites, an innovative and simple functionalized strategy has been proposed by grafting 4,4?-oxydianiline (ODA) onto carbon fiber surface using hexachlorocyclophosphazene (HCCP) as a novel coupling agent at mild reaction conditions. The chemical composition of the CF surface was confirmed by X-ray photoelectron spectra (XPS). The surface topography and surface energy of CF were examined by atomic force microscope (AFM) and dynamic contact angle tests (DCA), respectively. The interfacial shear strength (IFSS) of CF reinforced composites was studied by microbond test. The tensile strength of CF was measured by single filament tensile test. After functionalization treatment, the grafted amine groups on the fiber surface enhanced the surface wettability of modified CF and formed strong chemical bonding between fiber and matrix, improving the interfacial adhesion strength of composites. The interfacial shear strength of modified CF reinforced composites increased by 71.2% compared with that of desized CF. The interfacial enhancement mechanism was also discussed in detail. Moreover, the modified CF almost kept the original mechanical properties after functionalization.

  14. A general protocol to coat titania shell on carbon-based composite cores using carbon as coupling agent

    SciTech Connect

    Zheng Rongbo; Meng Xianwei; Tang Fangqiong

    2009-05-15

    We present herein a general protocol to coat titania shell on carbon-based composite cores via the hydrolysis of titanium tetrabutoxide in a mixed solvent with the catalysis of ammonia. As coupling agent, their carbonaceous component can adsorb counter-charged NH{sub 4}{sup +}, and then the negatively charged ident toTiO{sup -} species are adsorbed via electrostatic interaction to form TiO{sub 2} shell. Various carbon-based cores with different functional components, such as Ag/C core/shell spheres, Ag/C nanocables, as well as magnetic (C-Fe{sub 3}O{sub 4}) hollow spheres can be coated with titania shell to form corresponding core/shell composites. Their optical or magnetic property is also investigated. Finally, anatase-phase titania shell with rough surface can be generated via hydrothermal treatment of aforementioned titania coated composites, which can further introduce the properties of anatase-phase titania to the composites. - Graphical abstract: A general protocol was developed to coat titania shell on carbon-based composite cores based on the carbonaceous surface. Typically, Ag/C/TiO{sub 2} core/shell spheres were formed via this method.

  15. COUPLING

    DOEpatents

    Frisch, E.; Johnson, C.G.

    1962-05-15

    A detachable coupling arrangement is described which provides for varying the length of the handle of a tool used in relatively narrow channels. The arrangement consists of mating the key and keyhole formations in the cooperating handle sections. (AEC)

  16. Improve the Strength of PLA/HA Composite Through the Use of Surface Initiated Polymerization and Phosphonic Acid Coupling Agent

    PubMed Central

    Wang, Tongxin; Chow, Laurence C.; Frukhtbeyn, Stanislav A.; Ting, Andy Hai; Dong, Quanxiao; Yang, Mingshu; Mitchell, James W.

    2012-01-01

    Bioresorbable composite made from degradable polymers, e.g., polylactide (PLA), and bioactive calcium phosphates, e.g., hydroxyapatite (HA), are clinically desirable for bone fixation, repair and tissue engineering because they do not need to be removed by surgery after the bone heals. However, preparation of PLA/HA composite from non-modified HA usually results in mechanical strength reductions due to a weak interface between PLA and HA. In this study, a calcium-phosphate/phosphonate hybrid shell was developed to introduce a greater amount of reactive hydroxyl groups onto the HA particles. Then, PLA was successfully grafted on HA by surface-initiated polymerization through the non-ionic surface hydroxyl groups. Thermogravimetric analysis indiated that the amount of grafted PLA on HA can be up to 7 %, which is about 50 % greater than that from the literature. PLA grafted HA shows significantly different pH dependent ?-potential and particle size profiles from those of uncoated HA. By combining the phosphonic acid coupling agent and surface initiated polymerization, PLA could directly link to HA through covalent bond so that the interfacial interaction in the PLA/HA composite can be significantly improved. The diametral tensile strength of PLA/HA composite prepared from PLA-grafted HA was found to be over twice that of the composite prepared from the non-modified HA. Moreover, the tensile strength of the improved composite was 23 % higher than that of PLA alone. By varying additional variables, this approach has the potential to produce bioresorbable composites with improved mechanical properties that are in the range of natural bones, and can have wide applications for bone fixation and repair in load-bearing areas. PMID:22399838

  17. Investigation of oil recovery improvement by coupling an interfacial tension agent and a mobility control agent in light oil reservoirs. Summary annual report, October 1994--September 1995

    SciTech Connect

    Pitts, M.J.

    1995-12-31

    The study will investigate two major areas concerning co-injecting an interfacial tension reduction agent(s) and a mobility control agent into petroleum reservoirs. The first will consist of defining the mechanisms of interaction of an alkaline agent, a surfactant, and a polymer on a fluid-fluid and a fluid-rock basis. The second is the improvement of the economics of the combined technology. The third year of the study finished the oil recovery coreflood studies and evaluated different techniques to improve alkaline-surfactant-polymer solution economics. The final series of corefloods compared the oil recovery efficiency of the alkali gradient in Berea sandstone and J Sand sandstone. Oil recovery efficiency was essentially the same in both types of core, 13 to 15% PV of oil. Cost of chemical per incremental barrel of oil with 30% pore volume of alkaline-surfactant- polymer solution injected were $3.20 for the Na{sub 2}CO{sub 3}- Petrostep B-100-Flopaam 3330S solution in both types of core.

  18. Enhanced heat transfer through filler-polymer interface by surface-coupling agent in heat-dissipation material: A non-equilibrium molecular dynamics study

    SciTech Connect

    Tanaka, Kouichi; Ogata, Shuji; Kobayashi, Ryo; Tamura, Tomoyuki; Kitsunezuka, Masashi; Shinma, Atsushi

    2013-11-21

    Developing a composite material of polymers and micrometer-sized fillers with higher heat conductance is crucial to realize modular packaging of electronic components at higher densities. Enhancement mechanisms of the heat conductance of the polymer-filler interfaces by adding the surface-coupling agent in such a polymer composite material are investigated through the non-equilibrium molecular dynamics (MD) simulation. A simulation system is composed of α-alumina as the filler, bisphenol-A epoxy molecules as the polymers, and model molecules for the surface-coupling agent. The inter-atomic potential between the α-alumina and surface-coupling molecule, which is essential in the present MD simulation, is constructed to reproduce the calculated energies with the electronic density-functional theory. Through the non-equilibrium MD simulation runs, we find that the thermal resistance at the interface decreases significantly by increasing either number or lengths of the surface-coupling molecules and that the effective thermal conductivity of the system approaches to the theoretical value corresponding to zero thermal-resistance at the interface. Detailed analyses about the atomic configurations and local temperatures around the interface are performed to identify heat-transfer routes through the interface.

  19. Purification method directly impacts effectiveness of an EGF-coupled targeting agent for noninvasive tumor detection in mice

    PubMed Central

    Kovar, Joy L.; Volcheck, William M.; Chen, Jiyan; Simpson, Melanie A.

    2007-01-01

    Receptor targeting is an effective method of enhancing fluorescence signal in tumors for optical imaging. We previously used EGF conjugated to IRDye® 800CW to detect and track orthotopic prostate tumors in mice. In this study, our goal was to identify a reliable assay for targeting agent integrity in vitro that correlated with signal strength in vivo. Binding of IRDye® 800CW EGF to intact A431 human epidermoid carcinoma cells was quantified in a microplate assay. Specificity was confirmed by competition with unlabeled EGF or monoclonal antibody blocking. Biological activity of intact and damaged targeting agents relative to unlabeled EGF was determined by binding and stimulation of ERK phosphorylation. Both assays indicated a reduction of up to 60% of the fluorescence intensity with damaged agents. Using a research prototype imaging system optimized for IRDye® 800CW detection, we compared the efficacy of intact and damaged targeting agents for imaging subcutaneous tumors in mice. In live animal images and in sections of the excised tumors, damaged targeting agents consistently yielded diminished fluorescence signals corresponding to the reduction observed in microplate assays. This is the first study to directly correlate targeting agent signal strength in whole cell binding, in-cell western and in vivo near-infrared imaging. PMID:17188228

  20. Analysis of gadolinium-based contrast agents in tap water with a new hydrophilic interaction chromatography (ZIC-cHILIC) hyphenated with inductively coupled plasma mass spectrometry.

    PubMed

    Lindner, Uwe; Lingott, Jana; Richter, Silke; Jiang, Wen; Jakubowski, Norbert; Panne, Ulrich

    2015-03-01

    Hydrophilic interaction chromatography (HILIC) coupled with inductively coupled plasma mass spectrometry (ICP-MS) were optimised for the direct determination of gadolinium-based contrast agents in tap water. In comparison to our previous work, a new developed zwitterionic HILIC column (ZIC-cHILIC) was used for speciation of Gd-containing contrast agents. The limit of quantification (LOQ) for the five contrast agents Gd-BOPTA, Gd-DPTA-BMA, Gd-BT-DO3A, Gd-DOTA and Gd-DTPA are in the range of 5-12 ng Gd per litre. Additionally, a new internal standard, Pr-DOTA, was investigated to correct intensity drifts, minor and major changes in the sample volumes and possible matrix effects. With the speciation method described, tap water samples from the area of Berlin were analysed and for the first time, three Gd species, Gd-BT-DO3A, Gd-DOTA and Gd-BOPTA, were found in tap water samples at concentrations of about 10-20 ng Gd per litre. These are the same Gd species which have been previously detected predominantly in surface waters of the Berlin area. PMID:25486924

  1. [Scanning electron microscopy studies of the marginal finish conditions of tooth neck ceramic inlays treated with a silane coupling agents and bonded with a composite].

    PubMed

    Meissner, M; Beetke, E; Beer, R

    1989-01-01

    The therapy of cervical lesions in the visible facial area is not free of problems. The aim of this study is to investigate the marginal leakage by means of SEM analysis after in vitro and in vivo application of porcelain inlays in the cervical area, bonded to the enamel by a microfilled composite. Our results show, that the bond between composite and enamel is better than the bond between composite and inlay treated with a silane coupling agent. Problems of the leakage size and of the transparency can favourably be influenced by the composite as cementation material. PMID:2530731

  2. Novel One-pot Fabrication of Lab-on-a-Bubble@Ag Substrate without Coupling-agent for Surface Enhanced Raman Scattering

    PubMed Central

    Jiang, Jizhou; Ou-Yang, Lei; Zhu, Lihua; Zou, Jing; Tang, Heqing

    2014-01-01

    Through in-situ reduction of silver nitrate without using any coupling-agent, a substrate for surface-enhanced Raman scattering (SERS) was prepared by coating silver on hollow buoyant silica microspheres as a lab on a bubble (LoB). The silver coated LoBs (LoBs@Ag) floated on surface of a solution could provide a very convenient platform for the detection of target molecules in the solution. The LoBs@Ag substrate not only immobilized well-distributed Ag nanoparticles on the surface LoBs, but excluded the interference of coupling agents. This yielded high-resolution SERS spectra with excellent reproducibility. The adsorption of crystal violet (CV) on the LoBs@Ag substrate was investigated by means of SERS combined with density functional theory (DFT) calculations. The LoBs@Ag substrate exhibited a remarkable Raman enhancement effect for CV with an enhancement factor of 6.9 × 108 and wide adaptability from dye, pesticide to bio-molecules. On the basis of this substrate, a simple and sensitive SERS method was proposed for the determination of trace organic pollutants or bio-molecules. PMID:24487575

  3. Prostaglandin E2, a postulated astrocyte-derived neurovascular coupling agent, constricts rather than dilates parenchymal arterioles

    PubMed Central

    Dabertrand, Fabrice; Hannah, Rachael M; Pearson, Jessica M; Hill-Eubanks, David C; Brayden, Joseph E; Nelson, Mark T

    2013-01-01

    It has been proposed that prostaglandin E2 (PGE2) is released from astrocytic endfeet to dilate parenchymal arterioles through activation of prostanoid (EP4) receptors during neurovascular coupling. However, the direct effects of PGE2 on isolated parenchymal arterioles have not been tested. Here, we examined the effects of PGE2 on the diameter of isolated pressurized parenchymal arterioles from rat and mouse brain. Contrary to the prevailing assumption, we found that PGE2 (0.1, 1, and 5 μmol/L) constricted rather than dilated parenchymal arterioles. Vasoconstriction to PGE2 was prevented by inhibitors of EP1 receptors. These results strongly argue against a direct role of PGE2 on arterioles during neurovascular coupling. PMID:23385200

  4. Cloud point extraction with/without chelating agent on-line coupled with inductively coupled plasma optical emission spectrometry for the determination of trace rare earth elements in biological samples.

    PubMed

    Li, Yingjie; Hu, Bin

    2010-02-15

    The on-line incorporation of cloud point extraction (CPE) with/without 8-hydroxyquinoline (8-Ox) as chelating agent into flow injection analysis associated with inductively coupled plasma optical emission spectrometry (ICP-OES) for determining trace rare earth elements (REEs) is presented and evaluated. The significant parameters affecting on-line cloud point extraction of REEs such as sample pH, flow rate, 8-Ox concentration, Triton X-114 concentration were systematically studied. Under the optimized conditions, with the consumption of 3.0 mL sample solution, the limits of detection (3 sigma) were ranged from 41.4 pg mL(-1) (Yb) to 448 pg mL(-1) (Gd) with relative standard deviations (RSDs) of 1.0% (Eu)-5.9% (Sm) for on-line CPE-ICP-OES with 8-Ox as chelating agent, and 69.0 pg mL(-1) (Sc) to 509.5 pg mL(-1) (Sm) with RSDs of 2.9% (Yb)-7.5% (Ho) for on-line CPE-ICP-OES without 8-Ox as chelating agent, respectively. The sample throughput of 17samples h(-1) was obtained for both systems. The developed methods of on-line CPE-ICP-OES were validated by the analysis of certified reference material (GBW07605, tea leaves) and real biological samples of pig liver, Auricularia auricula and mushroom. PMID:19815341

  5. TiO2 nanoparticles functionalized monolithic capillary microextraction online coupled with inductively coupled plasma mass spectrometry for the analysis of Gd ion and gd-based contrast agents in human urine.

    PubMed

    Liu, Xiaolan; Chen, Beibei; Zhang, Lin; Song, Shiyao; Cai, Yabing; He, Man; Hu, Bin

    2015-09-01

    In this work, a novel method of TiO2 nanoparticles (NPs) functionalized monolithic capillary microextraction (CME) online coupling with inductively coupled plasma mass spectrometry (ICPMS) was developed for the sequential determination of Gd(3+) and Gd-based contrast agents in human urine samples. The monolithic capillary was prepared by embedding anatase TiO2 NPS in the poly(methacrylic acid-ethylene glycol dimethacrylate) (MAA-EDMA) framework. The Gd(3+) and Gd-based contrast agents (such as gadolinium-diethylene triamine pentaacetic acid (Gd-DTPA) and Gd-DTPA-bismethylamide (Gd-DTPA-BMA)) display different adsorption behaviors on the prepared monolithic capillary which possesses the adsorption properties of both anatase TiO2 NPS and poly(MAA-EDMA) monolith. Under the optimized conditions, the limits of detection (LODs) were found to be 3.6, 3.2, and 4.5 ng L(-1) for Gd(3+), Gd-DTPA, and Gd-DTPA-BMA, respectively, which are the lowest up to date. The enrichment factor was 25-fold with the sample throughput of 5 h(-1). The proposed method was validated by the analysis of Gd(3+) and Gd-DTPA in the healthy human urine samples as well as Gd(3+) and Gd-DTPA-BMA in patient urine samples. It was found that only a small amount of the free Gd(3+) was released from Gd-DTPA-BMA, and accurate results could be obtained since no oxidation/reduction or subtraction is involved in this method. This method is simple, sensitive, and rapid and provides a very attractive nonchromatography strategy for the speciation of Gd(3+) and Gd-based contrast agents in urine samples. PMID:26239367

  6. X-ray photoelectron spectroscopy studies of bond structure between polyvinyl alcohol and a titanate cross-coupling agent

    SciTech Connect

    Guelguen, M.A.; Popoola, O.O.; Kriven, W.M.

    1995-06-01

    Chemical interactions between polyvinyl alcohol (PVA) and triethanol amine titanate chelate were studied using x-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM). The titanate chelate cross coupled the PVA solution and produced a viscous gel. The gel had a three- dimensional network structure containing --C{sub PVA}--O--Ti--O--C{sub PVA}--organic complexes. A new C(1{ital s}) signature at 285.7 eV and an O(1{ital s}) signature at 531.25 eV were associated with the formation of these complexes. The water of the PVA solution was physically retained in the gelled structure and was readily available for chemical reactions. The removal of this entrapped water was irreversible and lead to a collapsed film of Ti-cross-linked PVA.

  7. Indium-zinc-oxide electric-double-layer thin-film transistors gated by silane coupling agents 3-triethoxysilylpropylamine-graphene oxide solid electrolyte

    NASA Astrophysics Data System (ADS)

    Guo, Liqiang; Huang, Yukai; Shi, Yangyang; Cheng, Guanggui; Ding, Jianning

    2015-07-01

    Silane coupling agents 3-triethoxysilylpropyla-mine-graphene oxide (KH550-GO) solid electrolyte are prepared by spin coating process. A high proton conductivity of ~1.2???×???10-3 Scm-1 is obtained at room temperature. A strong electric-double-layer (EDL) effect is observed due to the accumulation of protons at KH550-GO/IZO interface. Indium-Zinc-Oxide thin film transistors gated by KH550-GO solid electrolyte are self-assembled on ITO glass substrates. Good electrical performances are obtained, such as a low subthreshold swing of ~140?mV/dec., a high current on/off ratio of ~2.9???×???107 and a high field-effect mobility of ~13.2?cm2 V-1 S-1, respectively.

  8. Portable Solid Phase Micro-Extraction Coupled with Ion Mobility Spectrometry System for On-Site Analysis of Chemical Warfare Agents and Simulants in Water Samples

    PubMed Central

    Yang, Liu; Han, Qiang; Cao, Shuya; Yang, Jie; Yang, Junchao; Ding, Mingyu

    2014-01-01

    On-site analysis is an efficient approach to facilitate analysis at the location of the system under investigation as it can result in more accurate, more precise and quickly available analytical data. In our work, a novel self-made thermal desorption based interface was fabricated to couple solid-phase microextraction with ion mobility spectrometry for on-site water analysis. The portable interface can be connected with the front-end of an ion mobility spectrometer directly without other modifications. The analytical performance was evaluated via the extraction of chemical warfare agents and simulants in water samples. Several parameters including ionic strength and extraction time have been investigated in detail. The application of the developed method afforded satisfactory recoveries ranging from 72.9% to 114.4% when applied to the analysis of real water samples. PMID:25384006

  9. Portable solid phase micro-extraction coupled with ion mobility spectrometry system for on-site analysis of chemical warfare agents and simulants in water samples.

    PubMed

    Yang, Liu; Han, Qiang; Cao, Shuya; Yang, Jie; Yang, Junchao; Ding, Mingyu

    2014-01-01

    On-site analysis is an efficient approach to facilitate analysis at the location of the system under investigation as it can result in more accurate, more precise and quickly available analytical data. In our work, a novel self-made thermal desorption based interface was fabricated to couple solid-phase microextraction with ion mobility spectrometry for on-site water analysis. The portable interface can be connected with the front-end of an ion mobility spectrometer directly without other modifications. The analytical performance was evaluated via the extraction of chemical warfare agents and simulants in water samples. Several parameters including ionic strength and extraction time have been investigated in detail. The application of the developed method afforded satisfactory recoveries ranging from 72.9% to 114.4% when applied to the analysis of real water samples. PMID:25384006

  10. Determination of six chemotherapeutic agents in municipal wastewater using online solid-phase extraction coupled to liquid chromatography-tandem mass spectrometry.

    PubMed

    Rabii, Farida W; Segura, Pedro A; Fayad, Paul B; Sauvé, Sébastien

    2014-07-15

    Due to the increased consumption of chemotherapeutic agents, their high toxicity, carcinogenicity, their occurrence in the aquatic environment must be properly evaluated. An analytical method based on online solid-phase extraction coupled to liquid chromatography-tandem mass spectrometry was developed and validated. A 1 mL injection volume was used to quantify six of the most widely used cytotoxic drugs (cyclophosphamide, gemcitabine, ifosfamide, methotrexate, irinotecan and epirubicin) in municipal wastewater. The method was validated using standard additions. The validation results in wastewater influent had coefficients of determination (R(2)) between 0.983 and 0.998 and intra-day precision ranging from 7 to 13% (expressed as relative standard deviation %RSD), and from 9 to 23% for inter-day precision. Limits of detection ranged from 4 to 20 ng L(-1) while recovery values were greater than 70% except for gemcitabine, which is the most hydrophilic compound in the selected group and had a recovery of 47%. Matrix effects were interpreted by signal suppression and ranged from 55 to 118% with cyclophosphamide having the highest value. Two of the target anticancer drugs (cyclophosphamide and methotrexate) were detected and quantified in wastewater (effluent and influent) and ranged from 13 to 60 ng L(-1). The proposed method thus allows proper monitoring of potential environmental releases of chemotherapy agents. PMID:24388503

  11. Intefacial mobility and its effect on flexural strength and fracture toughness in glass fiber reinforced epoxy laminates

    SciTech Connect

    Wang, T.W.H.; Blum, F.D.

    1995-12-01

    Constant-strain-rate mechanical testing was used to study the fracture mechanical characterization of E-glass fiber fabrics reinforced epoxy composites. Testing was performed as a function of the silane coupling agents used with a compact tension (CT) specimen for fracture toughness and rectangular specimen for flexural strength. Two silane coupling agents, {gamma}-aminopropyltriethoxysilane (APS) and {gamma}-aminobutyltrithoxy-silane (ABS) were used for this purpose. The fracture toughness, K{sub lc}, of ABS treated composites was shown to be lower than that for APS treated composites. Treatment with either is better than using bare glass. A three point bend test showed the flexural strength and modulus were increased in order of untreatedcoupling agent layer.

  12. Production of Galactooligosaccharides Using ?-Galactosidase Immobilized on Chitosan-Coated Magnetic Nanoparticles with Tris(hydroxymethyl)phosphine as an Optional Coupling Agent

    PubMed Central

    Chen, Su-Ching; Duan, Kow-Jen

    2015-01-01

    ?-Galactosidase was immobilized on chitosan-coated magnetic Fe3O4 nanoparticles and was used to produce galactooligosaccharides (GOS) from lactose. Immobilized enzyme was prepared with or without the coupling agent, tris(hydroxymethyl)phosphine (THP). The two immobilized systems and the free enzyme achieved their maximum activity at pH 6.0 with an optimal temperature of 50 °C. The immobilized enzymes showed higher activities at a wider range of temperatures and pH. Furthermore, the immobilized enzyme coupled with THP showed higher thermal stability than that without THP. However, activity retention of batchwise reactions was similar for both immobilized systems. All the three enzyme systems produced GOS compound with similar concentration profiles, with a maximum GOS yield of 50.5% from 36% (w·v?1) lactose on a dry weight basis. The chitosan-coated magnetic Fe3O4 nanoparticles can be regenerated using a desorption/re-adsorption process described in this study. PMID:26047337

  13. Design, Synthesis, and Validation of an Effective, Reusable Silicon-Based Transfer Agent for Room-Temperature Pd-Catalyzed Cross-Coupling Reactions of Aryl and Heteroaryl Chlorides with Readily Available Aryl Lithium Reagents.

    PubMed

    Martinez-Solorio, Dionicio; Melillo, Bruno; Sanchez, Luis; Liang, Yong; Lam, Erwin; Houk, K N; Smith, Amos B

    2016-02-17

    A reusable silicon-based transfer agent (1) has been designed, synthesized, and validated for effective room-temperature palladium-catalyzed cross-coupling reactions (CCRs) of aryl and heteroaryl chlorides with readily accessible aryl lithium reagents. The crystalline, bench-stable siloxane transfer agent (1) is easily prepared via a one-step protocol. Importantly, this "green" CCR protocol circumvents prefunctionalization, isolation of organometallic cross-coupling partners, and/or stoichiometric waste aside from LiCl. DFT calculations support a ?-bond metathesis mechanism during transmetalation and lead to insights on the importance of the CF3 groups. PMID:26835838

  14. Gadolinium-based Contrast Agent Accumulates in the Brain Even in Subjects without Severe Renal Dysfunction: Evaluation of Autopsy Brain Specimens with Inductively Coupled Plasma Mass Spectroscopy.

    TOXLINE Toxicology Bibliographic Information

    Kanda T; Fukusato T; Matsuda M; Toyoda K; Oba H; Kotoku J; Haruyama T; Kitajima K; Furui S

    2015-01-01

    PURPOSE: To use inductively coupled plasma mass spectroscopy (ICP-MS) to evaluate gadolinium accumulation in brain tissues, including the dentate nucleus (DN) and globus pallidus (GP), in subjects who received a gadolinium-based contrast agent (GBCA).MATERIALS AND METHODS: Institutional review board approval was obtained for this study. Written informed consent for postmortem investigation was obtained either from the subject prior to his or her death or afterward from the subject's relatives. Brain tissues obtained at autopsy in five subjects who received a linear GBCA (GBCA group) and five subjects with no history of GBCA administration (non-GBCA group) were examined with ICP-MS. Formalin-fixed DN tissue, the inner segment of the GP, cerebellar white matter, the frontal lobe cortex, and frontal lobe white matter were obtained, and their gadolinium concentrations were measured. None of the subjects had received a diagnosis of severely compromised renal function (estimated glomerular filtration rate <45 mL/min/1.73 m(2)) or acute renal failure. Fisher permutation test was used to compare gadolinium concentrations between the two groups and among brain regions.RESULTS: Gadolinium was detected in all specimens in the GBCA agent group (mean, 0.25 µg per gram of brain tissue ± 0.44 [standard deviation]), with significantly higher concentrations in each region (P = .004 vs the non-GBCA group for all regions). In the GBCA group, the DN and GP showed significantly higher gadolinium concentrations (mean, 0.44 µg/g ± 0.63) than other regions (0.12 µg/g ± 0.16) (P = .029).CONCLUSION: Even in subjects without severe renal dysfunction, GBCA administration causes gadolinium accumulation in the brain, especially in the DN and GP.

  15. Cinnamaldehyde Characterization as an Antibacterial Agent toward E. coli Metabolic Profile Using 96-Blade Solid-Phase Microextraction Coupled to Liquid Chromatography-Mass Spectrometry.

    PubMed

    Mousavi, Fatemeh; Bojko, Barbara; Bessonneau, Vincent; Pawliszyn, Janusz

    2016-03-01

    Sampling and sample preparation plays an important role in untargeted analysis as it influences final composition of the analyzed extract and consequently reflection of the metabolome. In the current work, mechanism of bactericidal action of cinnamaldehyde (CA) against Escherichia coli (E. coli) during bacteria growth applying high-throughput solid-phase microextraction in direct immersion mode coupled to a high-performance liquid chromatography-mass spectrometry system was investigated. Numerous discriminant metabolites due to CA addition to the bacteria culture were mapped in the E. coli metabolic pathways. We propose new metabolic pathways confirming that CA acts as an oxidative stress agent against E. coli. The results of the current research have successfully demonstrated that CA changes the bacterial metabolism through interactions with different biochemical families such as proteins, nucleic acids, lipids, and carbohydrates, which needs further validation by proteomics and transcriptomics studies. The results presented here show the great potential of the novel approach in drug discovery and food safety. PMID:26811002

  16. Simulating the effects of native vegetation configurations on water quality using a multi-agent system coupled to a distributed hydrological process model

    NASA Astrophysics Data System (ADS)

    Ryan, J. G.; McAlpine, C. A.; Ludwig, J. A.

    2004-12-01

    Within Australia, excessive clearing of native vegetation has resulted in many landscapes becoming increasingly dysfunctional with respect to the retention of water and nutrients, and the maintenance of biodiversity. This problem is being addressed by the National Action Plan for Salinity and Water Quality, which promotes the management of vegetation cover at the farm and catchment scale to: stabilize soils; regulate groundwater to control dryland salinity; minimize chemical residues, nutrients, and sediment run-off to streams and waterways; as well as the maintenance of environmental flows for healthy waterways. However, the performance of potential landscape designs for the retention of water, nutrients and sediments, such as the reestablishment of tree belts and riparian vegetation, must be socially and economically feasible as well as improving landscape function. The implementation of alternative design strategies occurs at the farm-scale, but also must be applicable at the hill-slope and catchment scales, as well as incorporating temporal variability, and be practical to implement where data is limiting. A method is presented based upon a coupled multi-agent system (MAS) simulation and distributed parameter hydrological process model to optimize the integration of native vegetation within agroecosystems, in order to maintain desired outcomes for sustainable landscape function.

  17. Solcoseryl, a tissue respiration stimulating agent, significantly enhances the effect of capacitively coupled electric field on the promotion of bone formation around dental implants.

    PubMed

    Ochi, Morio; Wang, Pao-Li; Ohura, Kiyoshi; Takashima, Shigenori; Kagami, Hiroyuki; Hirose, Yukito; Kaku, Tohru; Sakaguchi, Kunihiko

    2003-06-01

    In the present study we examined the combined effect of application of a capacitively coupled electric field (CCEF) and the tissue respiration stimulating agent, Solcoseryl, on the promotion of bone formation around dental implants histologically and mechanically. After a dental implant was inserted into each femur of Japanese white rabbits, Solcoseryl (2 ml/kg) was administered intravenously in the ear vein and a CCEF was applied for 4 h per day for 14 days. The degree of bone formation on microscopic observation, bone contact ratio, bone surface area ratio, and the level of removal torque of the implant in the Solcoseryl- and CCEF-treated group were significantly higher than the respective value in the control group, which had not been treated with Solcoseryl nor CCEF. Thus, the combination of CCEF stimulation and Solcoseryl effectively promoted the formation of new bone. It is suggested that the clinical use of a combination of CCEF stimulation and Solcoseryl for dental implants promotes osseointegration. PMID:12755779

  18. Bio-functionalization of magnetite nanoparticles using an aminophosphonic acid coupling agent: new, ultradispersed, iron-oxide folate nanoconjugates for cancer-specific targeting

    NASA Astrophysics Data System (ADS)

    Das, Manasmita; Mishra, Debasish; Maiti, T. K.; Basak, A.; Pramanik, P.

    2008-10-01

    The present study describes a systematic approach towards the design and development of novel, bio-functionalized, magneto-fluorescent nanoparticles for cancer-specific targeting. Biocompatible, hydrophilic, magneto-fluorescent nanoparticles with surface-pendant amine, carboxyl or aldehyde groups, to be later used for bio-conjugation, were designed using an aminophosphonic acid coupling agent. These magneto-fluorescent nanoparticles were further functionalized with folic acid, using diverse conjugation strategies. A series of new iron-oxide folate nanoconjugates with excellent aqueous dispersion stability and reasonably good hydrodynamic sizes under a wide range of physiological conditions were developed. These ultradispersed nanosystems were analyzed for their physicochemical properties and cancer-cell targeting ability, facilitated by surface modification with folic acid. The nanoparticle size, charge, surface chemistry, magnetic properties and colloidal stability were extensively studied using a variety of complementary techniques. Confocal microscopy, performed with folate receptor positive human cervical HeLa cancer cells, established that these non-cytotoxic iron-oxide folate nanoconjugates were effectively internalized by the target cells through receptor-mediated endocytosis. Cell-uptake behaviors of nanoparticles, studied using magnetically activated cell sorting (MACS), clearly demonstrated that cells over-expressing the human folate receptor internalized a higher level of these nanoparticle-folate conjugates than negative control cells.

  19. Infrared analysis of the effect of composition of silane blends of amino and alkyl silane blends in tertiary amine-catalyzed anhydride-cured epoxy mixtures. Technical report

    SciTech Connect

    Tidrick, S.L.; Ishida, H.; Koenig, J.L.

    1991-05-01

    The property enhancement caused by silane coupling agents in glass-reinforced epoxy matrices is a function of the structure and composition of the silane. The effect of hydrolyzed and nonhydrolyzed of various compositions of silane coupling agent blends of gamma aminopropyltriethoxysilane (APS) and either butyltriethoxysilane (BTS) or ethyltriethoxysilane (ETS) on the cure of a benzyldimethylamine (BDMA)-catalyzed, nadic methyl anhydride (NMA) cured diglycidyl ether of bisphenol-A type epoxy were investigated by Fourier transform infrared spectroscopy (FTIR). The presence of the amine group perturbs the alternating copolymerization of the anhydride and epoxy groups by initiating and catalyzing the reaction. Hydrolysis also promoted the reaction rate. Samples containing ETS cured more rapidly than those containing BTS at the same composition. Imide formation was not significant in the presence of the alkyl-ended silanes. A very simple mathematical simulation was invoked to justify assumptions made during data analysis.

  20. Facile synthesis of 1-alkoxy-1H-benzo- and 7-azabenzotriazoles from peptide coupling agents, mechanistic studies, and synthetic applications

    PubMed Central

    Singh, Manish K; Kumar, Mukesh; Chamala, Raghu Ram; Yedulla, Vijayender R; Wagner, Domenick; Leung, Evan; Yang, Lijia; Matin, Asha; Ahmad, Sadia

    2014-01-01

    Summary (1H-Benzo[d][1,2,3]triazol-1-yloxy)tris(dimethylamino)phosphonium hexafluorophosphate (BOP), 1H-benzo[d][1,2,3]triazol-1-yl 4-methylbenzenesulfonate (Bt-OTs), and 3H-[1,2,3]triazolo[4,5-b]pyridine-3-yl 4-methylbenzenesulfonate (At-OTs) are classically utilized in peptide synthesis for amide-bond formation. However, a previously undescribed reaction of these compounds with alcohols in the presence of a base, leads to 1-alkoxy-1H-benzo- (Bt-OR) and 7-azabenzotriazoles (At-OR). Although BOP undergoes reactions with alcohols to furnish 1-alkoxy-1H-benzotriazoles, Bt-OTs proved to be superior. Both, primary and secondary alcohols undergo reaction under generally mild reaction conditions. Correspondingly, 1-alkoxy-1H-7-azabenzotriazoles were synthesized from At-OTs. Mechanistically, there are three pathways by which these peptide-coupling agents can react with alcohols. From 31P{1H}, [18O]-labeling, and other chemical experiments, phosphonium and tosylate derivatives of alcohols seem to be intermediates. These then react with BtO? and AtO? produced in situ. In order to demonstrate broader utility, this novel reaction has been used to prepare a series of acyclic nucleoside-like compounds. Because BtO? is a nucleofuge, several Bt-OCH2Ar substrates have been evaluated in nucleophilic substitution reactions. Finally, the possible formation of Pd ?–allyl complexes by departure of BtO? has been queried. Thus, alpha-allylation of three cyclic ketones was evaluated with 1-(cinnamyloxy)-1H-benzo[d][1,2,3]triazole, via in situ formation of pyrrolidine enamines and Pd catalysis. PMID:25246951

  1. Rapid determination of X-ray contrast agent iomeprol in human plasma by on-line solid-phase extraction coupled with phase optimized liquid chromatography.

    PubMed

    Zhou, Tingting; Tao, Yun; Pu, Yabing; Morello, Rosa; Mei, Surong; Boos, Karl-Siegfried

    2015-06-15

    Phase optimized liquid chromatography (POPLC) allows for the optimized combination of column segments of any length and stationary phases with different functionalities. In this study, a simple and rapid method using POPLC coupled with on-line solid-phase extraction (SPE) for the analysis of X-ray contrast media agent iomeprol (IOM) in human plasma was developed. Because the phenyl (PH) stationary phase has strong hydrophobic and ?-? interactions with IOM and iopromide (IOP, internal standard), the best separation efficiency was achieved with a 250mm×3mm homogenous PH POPLC-column. Different kinds of on-line SPE sorbents were studied, including restricted access material-alkyl diol silica (ADS), LiChrolut EN with excellent absorption capacity and hydrophilic-lipophilic-balanced Oasis HLB. The most efficient on-line sample clean-up was carried out using a fast-flow on-line purification approach with an Oasis HLB pre-column ((20mm×2mm, 30?m). This pre-column showed excellent durability and reproducibility. At least 400 samples could be analyzed with one pre-column. Each plasma sample was directly injected and analyzed within 15min. The calibration curves were linear in the range of 10-1000?g/mL. The limit of quantitation was 2.26?g/mL. The inter-day precision of this method was excellent and less than 1.44%, and the intra-day precision was less than 4.44%. The inter-day and intra-day accuracy ranged from 94.33% to 104.36% and 94.60% to 101.71%, respectively. This validated method is expected to be useful in the analysis of human plasma samples for glomerular filtration rate (GFR) measurements and assessment of kidney function. PMID:25939093

  2. Qualitative screening of veterinary anti-microbial agents in tissues, milk, and eggs of food-producing animals using liquid chromatography coupled with tandem mass spectrometry.

    PubMed

    Chen, Dongmei; Yu, Jie; Tao, Yanfei; Pan, Yuanhu; Xie, Shuyu; Huang, Lingli; Peng, Dapeng; Wang, Xu; Wang, Yulian; Liu, Zhenli; Yuan, Zonghui

    2016-04-01

    A method for the analysis of 120 drugs in animal derived food was developed using liquid chromatography-tandem mass spectrometry (LC-MS/MS). These analytes belong to 12 families of veterinary anti-microbial agents (quinolones, macrolides, β-lactams, nitroimidazoles, sulfonamides, lincomycines, chloramphenicols, quinoxalines, tetracyclines, polypeptides, and antibacterial synergists) as well as other compounds not assigned to a particular drug family. The animal derived food samples include muscle and liver of swine, bovine, sheep, and chicken, as well as hen eggs and dairy milk. The sample preparation included ultrasound-assisted extraction (UAE) with acetonitrile-water and a final clean-up with auto solid-phase extraction (SPE) on HLB cartridges. The detection and quantification of 120 anti-microbial agents was performed using LC-MS/MS in positive and negative ion mode. The chromatographic separation was performed on a C18 column using acetonitrile and 0.1% formic acid as the mobile phase. The limit of detection (LOD) and limit of quantification (LOQ) of all drugs in food-producing animals were 0.5-3.0μg/kg and 1.5-10.0μg/kg, respectively. The developed method was successfully utilized to monitor real samples, which demonstrated that it is a simple, fast, and robust method, and could be used as a regulatory to screen for the presence of residues from veterinary anti-microbial drugs in animal-derived foods. PMID:26950031

  3. Biological Agents

    MedlinePLUS

    ... Español A to Z Index Contact Us FAQs Biological Agents This page requires that javascript be enabled ... and Health Topics A-Z Index What's New Biological agents include bacteria, viruses, fungi, other microorganisms and ...

  4. Influence of irofulven, a transcription-coupled repair-specific antitumor agent, on RNA polymerase activity, stability and dynamics in living mammalian cells.

    PubMed

    Escargueil, Alexandre E; Poindessous, Virginie; Soares, Daniele Grazziotin; Sarasin, Alain; Cook, Peter R; Larsen, Annette K

    2008-04-15

    Transcription-coupled repair (TCR) plays a key role in the repair of DNA lesions induced by bulky adducts and is initiated when the elongating RNA polymerase II (Pol II) stalls at DNA lesions. This is accompanied by alterations in Pol II activity and stability. We have previously shown that the monofunctional adducts formed by irofulven (6-hydroxymethylacylfulvene) are exclusively recognized by TCR, without involvement of global genome repair (GGR), making irofulven a unique tool to characterize TCR-associated processes in vivo. Here, we characterize the influence of irofulven on Pol II activity, stability and mobility in living mammalian cells. Our results demonstrate that irofulven induces specific inhibition of nucleoplasmic RNA synthesis, an important decrease of Pol II mobility, coupled to the accumulation of initiating polymerase and a time-dependent loss of the engaged enzyme, associated with its polyubiquitylation. Both proteasome-mediated degradation of the stalled polymerase and new protein synthesis are necessary to allow Pol II recycling into preinitiating complexes. Together, our findings provide novel insights into the subsequent fate of the stalled RNA polymerase II and demonstrate the essential role of the recycling process for transcriptional reinitiation and viability of mammalian cells. PMID:18388315

  5. Application of the McMurry Coupling Reaction in the Synthesis of Tri- and Tetra-arylethylene Analogues as Potential Cancer Chemotherapeutic Agents

    PubMed Central

    Tanpure, Rajendra P.; Harkrider, Amanda R.; Strecker, Tracy E.; Hamel, Ernest; Trawick, Mary Lynn; Pinney, Kevin G.

    2010-01-01

    Structural redesign of selected non-steroidal estrogen receptor binding compounds has previously been successful in the discovery of new inhibitors of tubulin assembly. Accordingly, tetra-substituted alkene analogues (21-30) were designed based in part on combinations of the structural and electronic components of tamoxifen and combretastatin A-4 (CA4). The McMurry coupling reaction was used as the key synthetic step in the preparation of these tri- and tetra-arylethylene analogues. The structural assignment of E, Z isomers was determined on the basis of 2D-NOESY experiments. The ability of these compounds to inhibit tubulin polymerization and cell growth in selected human cancer cell lines was evaluated. Although the compounds were found to be less potent than CA4, these analogues significantly advance the known structure activity relationship associated with the colchicine binding site on ?-tubulin. PMID:19733085

  6. Photogalvanic cell comprising complexing agents

    SciTech Connect

    Brokken-zijp, J.C.; Reinders, F.J.

    1980-02-26

    A photogalvanic cell containing a set of electrodes immersed in an acidic aqueous electrolyte solution is described. The solution comprises at least one photo-reducible dyestuff, both higher and lower valent ions of at least one redox couple of metals, and at least one complexing agent for the higher valent ion of the redox couple.

  7. Agent Orange

    MedlinePLUS

    ... Toll Free Numbers VA » Health Care » Public Health » Military Exposures » Agent Orange Public Health Menu Menu Public Health Public Health Home Military Exposures Military Exposures Home 4 Ways to Find ...

  8. [Inotropic agents].

    PubMed

    Sasayama, Shigetake

    2003-05-01

    Depression of myocardial contractility plays an important role in the development of heart failure and many inotropic agents were developed to improve the contractile function of the failing heart. Agents that increase cyclic AMP, either by increasing its synthesis or reducing its degradation, exerted dramatic short-term hemodynamic benefits, but these acute effects were not extrapolated into long-term improvement of the clinical outcome of heart failure patients. Administration of these agents to an energy starved failing heart would be expected to increase myocardial energy use and could accelerate disease progression. The role of digitalis in the management of heart failure has been controversial, however, the recent large scale clinical trial has ironically proved that digoxin reduced the rate of hospitalization both overall and for worsening heart failure. More recently, attention was paid to other inotropic agents that have a complex and diversified mechanism. These agents have some phosphodiesterase-inhibitory action but also possess additional effects, including cytokine inhibitors, immunomodulators, or calcium sensitizers. In the Western Societies these agents were again shown to increase mortality of patients with severe heart failure in a dose dependent manner with the long-term administration. However, it may not be the case in the Japanese population in whom mortality is relatively low. Chronic treatment with inotropic agent may be justified in Japanese, as it allows optimal care in the context of relief of symptoms and an improved quality of life. Therefore, each racial group should obtain specific evidence aimed at developing its own guidelines for therapy rather than translating major guidelines developed for other populations. PMID:12755007

  9. Dynamic Agents of Magnetosphere-Ionosphere Coupling

    NASA Technical Reports Server (NTRS)

    Khazanov, George V.; Rowland, Douglas E.; Moore, Thomas E.; Collier, Michael

    2011-01-01

    VISIONS sounding rocket mission (VISualizing Ion Outflow via Neutral atom imaging during a Substorm) has been awarded to NASA/GSFC (PI Rowland) in order to provide the first combined remote sensing and in situ measurements of the regions where ion acceleration to above 5 e V is occurring, and of the sources of free energy and acceleration mechanisms that accelerate the ions. The key science question of VISIONS is how, when, and where, are ions accelerated to escape velocities in the auroral zone below 1000 km, following substorm onset? Sources of free energy that power this ion acceleration process include (but not limited) electron precipitation, field-aligned currents, velocity shears, and Alfvenic Poynting flux. The combine effect of all these processes on ionospheric ion outflows will be investigated in a framework of the kinetic model that has been developed by Khazanov et al. in order to study the polar wind transport in the presence of photoelectrons.

  10. Silane coupling agents for corrosion protection

    NASA Astrophysics Data System (ADS)

    Subramanian, Vijay

    2000-10-01

    Organofunctional silanes have retained special attention of the adhesion world for a long time. The current work attempts to expand the areas of application of silanes into corrosion control of metals and alloys. Studies of selected functional and non-functional silane films formed on iron substrates showed that there is interaction between the amine functional group of gamma-aminopropyl trimethoxysilane (gamma-APS) and the iron substrate, the result of which is no improvement in corrosion protection. A non-functional silane, Bis-triethoxysilyl ethane (BTSE), on the other hand, formed more number of oxane bonds with the substrate, when applied from acidic pH range. This results in improved corrosion protection. A two-step silane treatment consisting of a non-functional first silane layer and a functional silane second layer is proposed, which can provide corrosion protection and adhesion enhancement. Several alloy systems and bis-silanes are investigated and the two step silane treatment is shown to improve both adhesion and corrosion performance. The selection of the silane application pH is shown to be related to the stability of the metal or oxide surface present. The roles of the first and second layer of the silane are corrosion protection and adhesion improvement with the top-coat respectively. Concentration of BTSE in the coating solution is shown to affect the properties of the protective film formed on AL 2024. The thickness of the silane film increases proportional to the concentration. Thinner films of BTSE reduce only the cathodic reaction rates at the metal surface, whereas thicker films substantially reduce both anodic and cathodic reaction rates. These results also match several performance tests including ASTM B-117 salt spray. On Al 1050, the oxide layer on the surface is shown to have little effect on the electrical properties of the BTSE film formed. Preheating the surface and curing of the deposited film strongly influence the electrical properties. The condensation reaction occurring during the curing process results in a hydrophobic silane film. This results in the emergence of a second relaxation in the impedance behavior, which is directly related to the resistance offered by the silane film towards corrosive attack.

  11. Sunscreening Agents

    PubMed Central

    Martis, Jacintha; Shobha, V; Sham Shinde, Rutuja; Bangera, Sudhakar; Krishnankutty, Binny; Bellary, Shantala; Varughese, Sunoj; Rao, Prabhakar; Naveen Kumar, B.R.

    2013-01-01

    The increasing incidence of skin cancers and photodamaging effects caused by ultraviolet radiation has increased the use of sunscreening agents, which have shown beneficial effects in reducing the symptoms and reoccurrence of these problems. Many sunscreen compounds are in use, but their safety and efficacy are still in question. Efficacy is measured through indices, such as sun protection factor, persistent pigment darkening protection factor, and COLIPA guidelines. The United States Food and Drug Administration and European Union have incorporated changes in their guidelines to help consumers select products based on their sun protection factor and protection against ultraviolet radiation, whereas the Indian regulatory agency has not yet issued any special guidance on sunscreening agents, as they are classified under cosmetics. In this article, the authors discuss the pharmacological actions of sunscreening agents as well as the available formulations, their benefits, possible health hazards, safety, challenges, and proper application technique. New technologies and scope for the development of sunscreening agents are also discussed as well as the role of the physician in patient education about the use of these agents. PMID:23320122

  12. Antidiabetic Agents.

    ERIC Educational Resources Information Center

    Plummer, Nancy; Michael, Nancy, Ed.

    This module on antidiabetic agents is intended for use in inservice or continuing education programs for persons who administer medications in long-term care facilities. Instructor information, including teaching suggestions, and a listing of recommended audiovisual materials and their sources appear first. The module goal and objectives are then…

  13. Antibiotic Agents

    MedlinePLUS

    ... wrappers and agents added to water involved in food processing. If a substance is not intended for use on or in the body, it is registered by the US Environmental Protection Agency (EPA) under the ... in the hospital and food industry); however, at the present time, this modest ...

  14. Antidiabetic Agents.

    ERIC Educational Resources Information Center

    Plummer, Nancy; Michael, Nancy, Ed.

    This module on antidiabetic agents is intended for use in inservice or continuing education programs for persons who administer medications in long-term care facilities. Instructor information, including teaching suggestions, and a listing of recommended audiovisual materials and their sources appear first. The module goal and objectives are then…

  15. Magnetized silane-coupling agent KH-570 based solid-phase extraction followed by gas chromatography-flame ionization detection to determine venlafaxine in human hair and aqueous environmental samples.

    PubMed

    Ebrahimi, Mahmoud; Ebrahimitalab, Abdolhossein; Es'haghi, Zarrin; Mohammadinejad, Arash

    2015-02-01

    In the present study, a novel adsorbent, Fe3O4 magnetic nanoparticles (MNPs) functionalized by silane-coupling agent KH-570, was successfully synthesized. The prepared MNPs were characterized by Fourier-transform infrared spectroscopy and transmission electron microscopy. It was applied as functionalized magnetic nano-adsorbent for magnetic solid-phase extraction of trace levels of venlafaxine using gas chromatography with flame ionization detector. This method was developed and optimized for use in analysis of venlafaxine in human hair and aqueous environmental samples. The main factors influencing the extraction efficiency including pH of sample, amount of the MNPs, adsorption time, volume of sample, and desorption conditions such as volume of solvent and desorption time were studied and optimized. Under the optimized experimental conditions, good linearity was observed in the range of 1-1,000 µg L(-1) for aqueous environmental samples with correlation coefficients (R (2)) 0.996. The limits of detection and quantification were 0.1 and 0.5 μg L(-1), respectively. Good reproducibility with the relative standard deviations (n = 5) 3.21 % was obtained. The developed method was successfully applied to the extraction of venlafaxine from spiked human hair, river water, and surface water samples and the relative recoveries of 89.36, 93.43, and 94.99 % were obtained, respectively. The results indicated that Fe3O4/KH-570 MNPs have a satisfying extraction efficiency and can be served as a sensitive, inexpensive, and reliable method for analysis of antidepressant drugs such as venlafaxine in biological and aqueous environmental samples. PMID:25367213

  16. [Biological agents].

    PubMed

    Amano, Koichi

    2009-03-01

    There are two types of biological agents for the treatment of rheumatoid arthritis (RA); monoclonal antibodies and recombinant proteins. Among the latter, etanercept, a recombinant fusion protein of soluble TNF receptor and IgG was approved in 2005 in Japan. The post-marketing surveillance of 13,894 RA patients revealed the efficacy and safety profiles of etanercept in the Japanese population, as well as overseas studies. Abatacept, a recombinant fusion protein of CTLA4 and IgG, is another biological agent for RA. Two clinical trials disclosed the efficacy of abatacept for difficult-to-treat patients: the AIM for MTX-resistant cases and the ATTAIN for patients who are resistant to anti-TNF. The ATTEST trial suggested abatacept might have more acceptable safety profile than infliximab. These biologics are also promising for the treatment of RA for not only relieving clinical symptoms and signs but retarding structural damage. PMID:19280938

  17. Antifungal agents.

    PubMed

    Ryder, N S

    1999-12-01

    At this year's ICAAC Meeting, new data on approximately 20 different antifungal agents were presented, while no new agents were disclosed. Drugs in late development include the triazoles, voriconazole (Pfizer Ltd) and Sch-56592 (Schering-Plough Corp), and the echinocandins, caspofungin (Merck & Co Inc) and FK-463 (Fujisawa Pharmaceutical Co Ltd). In contrast to previous years, presentations on these and earlier developmental compounds were relatively modest in scope, with few significant new data. Little new information appeared on the most recent novel class of agents, the sordarins (Glaxo Wellcome plc). Early clinical results were presented for FK-463, showing acceptable tolerability and dose-dependent efficacy in AIDS-associated esophageal candidiasis. A new liposomal formulation of nystatin (Nyotran; Aronex Pharmaceuticals Inc) was shown to be equivalent to conventional amphotericin B in empiric therapy of presumed fungal infection in neutropenic patients, but with reduced toxicity. Intravenous itraconazole (Janssen Pharmaceutica NV) was an effective prophylactic therapy in invasive pulmonary aspergillosis, while oral itraconazole was discussed as a treatment for fungal infection in heart and liver transplant patients. The allylamine compound, terbinafine (Novartis AG), showed good clinical efficacy against fungal mycetoma, a serious tropical infection. A major highlight was the first presentation of inhibitors of fungal efflux pumps as a strategy for overcoming resistance. MC-510027 (milbemycin alpha-9; Microcide Pharmaceuticals Inc) and its derivatives, potentiated the antifungal activity of triazoles and terbinafine in a number of Candida spp. Another pump inhibitor, MC-005172 (Microcide Pharmaceuticals Inc) showed in vivo potentiation of fluconazole in a mouse kidney infection model. Microcide Pharmaceuticals Inc also presented inhibitors of bacterial efflux pumps. PMID:16113946

  18. KGB agents

    NASA Astrophysics Data System (ADS)

    Gaina, Alex

    A short story is reported in which the activity of Communist Party of the USSR and secret KGB agents, which were payed by the State, in view of controlling of the conscience of population. The story reffers to the Physics Department of the Moscow University, Planing Institute of the Gosplan of Moldavian S.S.R. and Chishinau Technical University (actually: Technical University of Moldova), where the author has worked during Soviet times. Almost every 6-th citizen in the USSR was engaged in this activity, while actually the former communists rule in the Republic of Moldova.

  19. Detecting agents.

    PubMed Central

    Johnson, Susan C

    2003-01-01

    This paper reviews a recent set of behavioural studies that examine the scope and nature of the representational system underlying theory-of-mind development. Studies with typically developing infants, adults and children with autism all converge on the claim that there is a specialized input system that uses not only morphological cues, but also behavioural cues to categorize novel objects as agents. Evidence is reviewed in which 12- to 15-month-old infants treat certain non-human objects as if they have perceptual/attentional abilities, communicative abilities and goal-directed behaviour. They will follow the attentional orientation of an amorphously shaped novel object if it interacts contingently with them or with another person. They also seem to use a novel object's environmentally directed behaviour to determine its perceptual/attentional orientation and object-oriented goals. Results from adults and children with autism are strikingly similar, despite adults' contradictory beliefs about the objects in question and the failure of children with autism to ultimately develop more advanced theory-of-mind reasoning. The implications for a general theory-of-mind development are discussed. PMID:12689380

  20. Preparing Change Agents for Change Agent Roles.

    ERIC Educational Resources Information Center

    Sedlacek, James R.

    Seventy-seven Spanish- and Portuguese-speaking agricultural change agents from developing Central and South American countries responded to a questionnaire which sought perceptions of the roles in which the change agents felt they were involved and the roles for which they felt they were being trained. The agents were participating in training…

  1. Preparing Change Agents for Change Agent Roles.

    ERIC Educational Resources Information Center

    Sedlacek, James R.

    Seventy-seven Spanish- and Portuguese-speaking agricultural change agents from developing Central and South American countries responded to a questionnaire which sought perceptions of the roles in which the change agents felt they were involved and the roles for which they felt they were being trained. The agents were participating in training…

  2. Mother ship and physical agents collaboration

    NASA Astrophysics Data System (ADS)

    Young, Stuart H.; Budulas, Peter P.; Emmerman, Philip J.

    1999-07-01

    This paper discusses ongoing research at the U.S. Army Research Laboratory that investigates the feasibility of developing a collaboration architecture between small physical agents and a mother ship. This incudes the distribution of planning, perception, mobility, processing and communications requirements between the mother ship and the agents. Small physical agents of the future will be virtually everywhere on the battlefield of the 21st century. A mother ship that is coupled to a team of small collaborating physical agents (conducting tasks such as Reconnaissance, Surveillance, and Target Acquisition (RSTA); logistics; sentry; and communications relay) will be used to build a completely effective and mission capable intelligent system. The mother ship must have long-range mobility to deploy the small, highly maneuverable agents that will operate in urban environments and more localized areas, and act as a logistics base for the smaller agents. The mother ship also establishes a robust communications network between the agents and is the primary information disseminating and receiving point to the external world. Because of its global knowledge and processing power, the mother ship does the high-level control and planning for the collaborative physical agents. This high level control and interaction between the mother ship and its agents (including inter agent collaboration) will be software agent architecture based. The mother ship incorporates multi-resolution battlefield visualization and analysis technology, which aids in mission planning and sensor fusion.

  3. Riot Control Agents

    MedlinePLUS

    ... the area where the agents were released. Avoid dense, low-lying clouds of riot control agent vapor. ... possible, because riot control agents will form a dense vapor cloud that can travel close to the ...

  4. Remote Agent Demonstration

    NASA Technical Reports Server (NTRS)

    Dorais, Gregory A.; Kurien, James; Rajan, Kanna

    1999-01-01

    We describe the computer demonstration of the Remote Agent Experiment (RAX). The Remote Agent is a high-level, model-based, autonomous control agent being validated on the NASA Deep Space 1 spacecraft.

  5. Pinning synchronization of a mobile agent network

    NASA Astrophysics Data System (ADS)

    Wang, Lei; Sun, You-xian

    2009-11-01

    We investigate the problem of controlling a group of mobile agents in a plane in order to move them towards a desired orbit via pinning control, in which each agent is associated with a chaotic oscillator coupled with those of neighboring agents, and the pinning strategy is to have the common linear feedback acting on a small fraction of agents by random selection. We explore the effects of the pinning probability, feedback gains and agent density in the pinning synchronization of a mobile agent network under a fast-switching constraint, and perform numerical simulations for validation. In particular, we show that there exists a critical pinning density for network synchronization with an unbounded region: above the threshold, the dynamical network can be controlled by pinning; below it, anarchy prevails. And for the network with a single bounded synchronization region, pinning control has little effect as regards enhancing network synchronizability.

  6. Query Answering Driven by Collaborating Agents

    NASA Astrophysics Data System (ADS)

    Dardzinska, Agnieszka

    We assume that there is a group of collaborating agents where each agent is defined as an Information System coupled with a Query Answering System (QAS). Values of attributes in an information system S form atomic expressions of a language used by the agent associated with S to communicate with other agents. Collaboration among agents is initiated when one of the agent's, say the one associated with S and called a client, is asked by user to resolve a query containing nonlocal attributes for S. Then, the client will ask for help other agents to have that query answered. As the result of this request, knowledge in the form of defnitions of locally foreign attribute values for S is extracted at information systems representing other agents and sent to the client. The outcome of this step is a knowledge-base KB created at the client site and used to answer the query. In this paper we present a method of identifying which agents are semantically the closest to S and show that the precision and recall of QAS is getting increased when only these agents are ask for help by the client.

  7. Spacecraft sanitation agent development

    NASA Technical Reports Server (NTRS)

    1972-01-01

    The development of an effective sanitizing agent that is compatible with the spacecraft environment and the human occupant is discussed. Experimental results show that two sanitation agents must be used to satisfy mission requirements: one agent for personal hygiene and one for equipment maintenance. It was also recommended that a water rinse be used with the agents for best results, and that consideration be given to using the agents pressure packed or in aerosol formulations.

  8. Effect of glass fiber surface treatments on mechanical strength of epoxy based composite materials.

    PubMed

    Iglesias, J G; González-Benito, J; Aznar, A J; Bravo, J; Baselga, J

    2002-06-01

    Sizing glass fibers with silane coupling agents enhances the adhesion and the durability of the fiber/polymer matrix interface in composite materials. There are several tests to determine the interfacial strength between a fiber and resin, but all of them present difficulties in interpreting the results and/or sample preparation. In this study, we observed the influence of different aminosilanes fiber coatings on the resistance of epoxy-based composite materials using a very easy fractographic test. In addition, we tried a new fluorescence method to get information on a molecular level precisely at the interface. Strength was taken into account from two standpoints: (i) mechanical strength and (ii) the resistance to hydrolysis of the interface in oriented glass-reinforced epoxy-based composites. Three silanes: gamma-aminopropyltriethoxysilane, gamma-Aminopropylmethyldiethoxysilane, and gamma-Aminopropyldimethylethoxysilane were used to obtain different molecular structures at the interface. It was concluded that: (i) the more accessible amine groups are, the higher the interface rigidity is; (ii) an interpenetrating network mechanism seems to be the most important for adhesion and therefore to the interfacial strength; and (iii) the higher the degree of crosslinking in the silane coupling layer is, the higher the hydrolytic damage rate is. PMID:16290658

  9. Total Synthesis of Bryostatin 16 using a Pd-Catalyzed Diyne-Coupling as Macrocyclization Method and Synthesis of C20-epi-Bryostatin 7 as a Potent Anticancer Agent

    PubMed Central

    Trost, Barry M.; Dong, Guangbin

    2010-01-01

    Asymmetric total synthesis of bryostatin 16 was achieved in 26 steps in the longest linear sequence/39 total steps from aldehyde 10. A Pd-catalyzed alkyne-alkyne coupling was employed for the first-time as a macrocyclization method in a natural product synthesis. A route to convert bryostatin 16 to a new family of bryostatin analogues was developed. Toward the end, 20-epi-bryostatin 7, was synthesized from a bryostatin 16-like intermediate; and the key step involves a Re-catalyzed epoxidation/ring-opening reaction. Preliminary biological studies indicated that this new analogue exhibits nanomolar anti-cancer activity against several cancer cell lines. PMID:21043491

  10. Helix coupling

    DOEpatents

    Ginell, W.S.

    1989-04-25

    A coupling for connecting helix members in series, which consists of a pair of U-shaped elements, one of which is attached to each helix end with the "U" sections of the elements interlocked. The coupling is particularly beneficial for interconnecting helical Nitinol elements utilized in thermal actuators or engines. Each coupling half is attached to the associated helix at two points, thereby providing axial load while being easily removed from the helix, and reusable.

  11. Helix coupling

    DOEpatents

    Ginell, W.S.

    1982-03-17

    A coupling for connecting helix members in series, which consists of a pair of U-shaped elements, one of which is attached to each helix end with the U sections of the elements interlocked. The coupling is particularly beneficial for interconnecting helical Nitinol elements utilized in thermal actuators or engines. Each coupling half is attached to the associated helix at two points, thereby providing axial load while being easily removed from the helix, and reusable.

  12. Radiographic scanning agent

    SciTech Connect

    Bevan, J.A.

    1981-01-27

    A composition and method for the preparation of a technetium-99m -based scanning agent are disclosed. The scanning agent is prepared from /sup 99m/Tc, in a +3, +4 and/or +5 oxidation state, and a methanehydroxydiphosphonate bone-seeking agent which carries the radionuclide to bone mineral. The methanehydroxydiphosphonate agent provides scan sharpness equivalent or superior to commercial scanning agents, and is superior for detecting myocardial infarcts, as compared with commercial scanning agents such as ethane-1-hydroxy-1,1-diphosphonate and methanediphosphonate.

  13. The development and validation of a rapid method for the determination of antimicrobial agent residues in milk and meat using ultra performance liquid chromatography coupled to quadrupole--Orbitrap mass spectrometry.

    PubMed

    Cepurnieks, Guntis; Rjabova, Jekaterina; Zacs, Dzintars; Bartkevics, Vadims

    2015-01-01

    A new multi-class method has been developed for the identification and quantification of the residues of 26 antibiotics from different classes (sulfonamides, macrolides, tetracyclines, penicillins, and quinolones) in milk and meat by ultra performance liquid chromatography coupled to hybrid quadrupole - high resolution Orbitrap mass spectrometry (UPLC-qOrbitrap). The sample preparation included extraction of two analytical portions with acetonitrile and 5% trichloroacetic acid, respectively, followed by centrifugation and filtration. The method was validated over three days at 50% of MRL (maximum residue limit) set in the European Union. Experiments on spiked meat and milk samples showed that the average recovery of the antibiotics ranged from 83% to 112%, and the coefficients of variation were between 8.9% and 39%. PMID:25282600

  14. Synthesis of (+)-Antroquinonol: An Antihyperglycemic Agent.

    PubMed

    Sulake, Rohidas S; Lin, Hsiao-Han; Hsu, Chia-Yu; Weng, Ching-Feng; Chen, Chinpiao

    2015-06-19

    The total synthesis of antroquinonol has been accomplished through Suzuki-Miyaura cross-coupling and Barton-McCombie reaction, and the α,β-unsaturation was achieved through selenylation and oxidation protocols. In vitro and in vivo studies on the glucose-lowering properties of antroquinonol indicate that it is a potential antidiabetic agent. PMID:26039178

  15. Mobile Agents Applications.

    ERIC Educational Resources Information Center

    Martins, Rosane Maria; Chaves, Magali Ribeiro; Pirmez, Luci; Rust da Costa Carmo, Luiz Fernando

    2001-01-01

    Discussion of the need to filter and retrieval relevant information from the Internet focuses on the use of mobile agents, specific software components which are based on distributed artificial intelligence and integrated systems. Surveys agent technology and discusses the agent building package used to develop two applications using IBM's Aglet…

  16. Hydroxypyridonate chelating agents

    SciTech Connect

    Raymond, K.N.; Scarrow, R.C.; White, D.L.

    1987-10-06

    Chelating agents are disclosed having 1-hydroxy-2-pyridinone (HOPO) and related moieties incorporated within their structures, including polydentate HOPO-substituted polyamines such as spermidine and spermine, and HOPO-substituted desferrioxamine. The chelating agents are useful in selectively removing certain cations from solution, and are particularly useful as ferric ion and actinide chelators. Novel syntheses of the chelating agents are provided.

  17. Hydroxypyridonate chelating agents

    DOEpatents

    Raymond, Kenneth N. (Berkeley, CA); Scarrow, Robert C. (Minneapolis, MN); White, David L. (Oakland, CA)

    1987-01-01

    Chelating agents having 1-hydroxy-2-pyridinone (HOPO) and related moieties incorporated within their structures, including polydentate HOPO-substituted polyamines such as spermidine and spermine, and HOPO-substituted desferrioxamine. The chelating agents are useful in selectively removing certain cations from solution, and are particularly useful as ferric ion and actinide chelators. Novel syntheses of the chelating agents are provided.

  18. Advances in HIV prevention for serodiscordant couples.

    PubMed

    Muessig, Kathryn E; Cohen, Myron S

    2014-12-01

    Serodiscordant couples play an important role in maintaining the global HIV epidemic. This review summarizes biobehavioral and biomedical HIV prevention options for serodiscordant couples focusing on advances in 2013 and 2014, including World Health Organization guidelines and best evidence for couples counseling, couple-based interventions, and the use of antiviral agents for prevention. In the past few years, marked advances have been made in HIV prevention for serodiscordant couples and numerous ongoing studies are continuously expanding HIV prevention tools, especially in the area of pre-exposure prophylaxis. Uptake and adherence to antiviral therapy remains a key challenge. Additional research is needed to develop evidence-based interventions for couples, and especially for male-male couples. Randomized trials have demonstrated the prevention benefits of antiretroviral-based approaches among serodiscordant couples; however, residual transmission observed in recognized serodiscordant couples represents an important and resolvable challenge in HIV prevention. PMID:25145645

  19. Advances in HIV Prevention for Serodiscordant Couples

    PubMed Central

    Muessig, Kathryn E.; Cohen, Myron S.

    2014-01-01

    Serodiscordant couples play an important role in maintaining the global HIV epidemic. This review summarizes biobehavioral and biomedical HIV prevention options for serodiscordant couples focusing on advances in 2013 and 2014, including World Health Organization guidelines and best-evidence for couples counseling, couples-based interventions, and the use of antiviral agents for prevention. In the past few years marked advances have been made in HIV prevention for serodiscordant couples and numerous ongoing studies are continuously expanding HIV prevention tools, especially in the area of pre-exposure prophylaxis. Uptake and adherence to antiviral therapy remains a key challenge. Additional research is needed to develop evidence-based interventions for couples, and especially for male-male couples. Randomized trials have demonstrated the prevention benefits of antiretroviral-based approaches among serodiscordant couples; however, residual transmission observed in recognized serodiscordant couples represents an important and resolvable challenge in HIV prevention. PMID:25145645

  20. Multi-agent autonomous system

    NASA Technical Reports Server (NTRS)

    Fink, Wolfgang (Inventor); Dohm, James (Inventor); Tarbell, Mark A. (Inventor)

    2010-01-01

    A multi-agent autonomous system for exploration of hazardous or inaccessible locations. The multi-agent autonomous system includes simple surface-based agents or craft controlled by an airborne tracking and command system. The airborne tracking and command system includes an instrument suite used to image an operational area and any craft deployed within the operational area. The image data is used to identify the craft, targets for exploration, and obstacles in the operational area. The tracking and command system determines paths for the surface-based craft using the identified targets and obstacles and commands the craft using simple movement commands to move through the operational area to the targets while avoiding the obstacles. Each craft includes its own instrument suite to collect information about the operational area that is transmitted back to the tracking and command system. The tracking and command system may be further coupled to a satellite system to provide additional image information about the operational area and provide operational and location commands to the tracking and command system.

  1. Proceedings of the Agent 2002 Conference on Social Agents : Ecology, Exchange, and Evolution

    SciTech Connect

    Macal, C., ed.; Sallach, D., ed.

    2003-04-10

    Welcome to the ''Proceedings'' of the third in a series of agent simulation conferences cosponsored by Argonne National Laboratory and The University of Chicago. The theme of this year's conference, ''Social Agents: Ecology, Exchange and Evolution'', was selected to foster the exchange of ideas on some of the most important social processes addressed by agent simulation models, namely: (1) The translation of ecology and ecological constraints into social dynamics; (2) The role of exchange processes, including the peer dependencies they create; and (3) The dynamics by which, and the attractor states toward which, social processes evolve. As stated in the ''Call for Papers'', throughout the social sciences, the simulation of social agents has emerged as an innovative and powerful research methodology. The promise of this approach, however, is accompanied by many challenges. First, modeling complexity in agents, environments, and interactions is non-trivial, and these representations must be explored and assessed systematically. Second, strategies used to represent complexities are differentially applicable to any particular problem space. Finally, to achieve sufficient generality, the design and experimentation inherent in agent simulation must be coupled with social and behavioral theory. Agent 2002 provides a forum for reviewing the current state of agent simulation scholarship, including research designed to address such outstanding issues. This year's conference introduces an extensive range of domains, models, and issues--from pre-literacy to future projections, from ecology to oligopolistic markets, and from design to validation. Four invited speakers highlighted major themes emerging from social agent simulation.

  2. Agent Architectures for Compliance

    NASA Astrophysics Data System (ADS)

    Burgemeestre, Brigitte; Hulstijn, Joris; Tan, Yao-Hua

    A Normative Multi-Agent System consists of autonomous agents who must comply with social norms. Different kinds of norms make different assumptions about the cognitive architecture of the agents. For example, a principle-based norm assumes that agents can reflect upon the consequences of their actions; a rule-based formulation only assumes that agents can avoid violations. In this paper we present several cognitive agent architectures for self-monitoring and compliance. We show how different assumptions about the cognitive architecture lead to different information needs when assessing compliance. The approach is validated with a case study of horizontal monitoring, an approach to corporate tax auditing recently introduced by the Dutch Customs and Tax Authority.

  3. Stabilized radiographic scanning agents

    SciTech Connect

    Fawzi, M.B.

    1980-11-11

    Stable compositions, useful as technetium-99m-based scintigraphic agents, comprise gentisic acid or a pharmaceutically-acceptable salt or ester thereof in combination with a pertechnetate reducing agent or dissolved in pertechnetate -99m (99mtco4-) solution. The compositions are especially useful in combination with a phosphate or phosphonate material which carries the radionuclide to bone, thus providing a skeletal imaging agent.

  4. DCTD — Featured Agents

    Cancer.gov

    DNA damaging agents are among the most successful treatments for cancer. The enzyme Poly(ADP-ribose)polymerase (abbreviated PARP) can facilitate repair of DNA damage caused by insult from chemotherapeutic agents and radiation. Increased PARP activity is associated with survival of some cancer cells. ABT-888, an orally bioavailable PARP-inhibitor developed by Abbott Laboratories, significantly enhanced the antitumor activity of DNA-damaging agents and radiation in preclinical models. Further development of this compound is ongoing.

  5. Prosthesis coupling

    NASA Technical Reports Server (NTRS)

    Reswick, J. B.; Mooney, V.; Bright, C. W.; Owens, L. J. (Inventor)

    1979-01-01

    A coupling for use in an apparatus for connecting a prosthesis to the bone of a stump of an amputated limb is described which permits a bio-compatible carbon sleeve forming a part of the prosthesis connector to float so as to prevent disturbing the skin seal around the carbon sleeve. The coupling includes a flexible member interposed between a socket that is inserted within an intermedullary cavity of the bone and the sleeve. A lock pin is carried by the prosthesis and has a stem portion which is adapted to be coaxially disposed and slideably within the tubular female socket for securing the prosthesis to the stump. The skin around the percutaneous carbon sleeve is able to move as a result of the flexing coupling so as to reduce stresses caused by changes in the stump shape and/or movement between the bone and the flesh portion of the stump.

  6. Chemical crowd control agents.

    PubMed

    Menezes, Ritesh G; Hussain, Syed Ather; Rameez, Mansoor Ali Merchant; Kharoshah, Magdy A; Madadin, Mohammed; Anwar, Naureen; Senthilkumaran, Subramanian

    2016-03-01

    Chemical crowd control agents are also referred to as riot control agents and are mainly used by civil authorities and government agencies to curtail civil disobedience gatherings or processions by large crowds. Common riot control agents used to disperse large numbers of individuals into smaller, less destructive, and more easily controllable numbers include chloroacetophenone, chlorobenzylidenemalononitrile, dibenzoxazepine, diphenylaminearsine, and oleoresin capsicum. In this paper, we discuss the emergency medical care needed by sufferers of acute chemical agent contamination and raise important issues concerning toxicology, safety and health. PMID:26658556

  7. Travel Agent Course Outline.

    ERIC Educational Resources Information Center

    British Columbia Dept. of Education, Victoria.

    Written for college entry-level travel agent training courses, this course outline can also be used for inservice training programs offered by travel agencies. The outline provides information on the work of a travel agent and gives clear statements on what learners must be able to do by the end of their training. Material is divided into eight…

  8. Change Agent Survival Guide

    ERIC Educational Resources Information Center

    Dunbar, Folwell L.

    2011-01-01

    Consulting is a rough racket. Only a tarantula hair above IRS agents, meter maids and used car sales people, the profession is a prickly burr for slings and arrows. Throw in education, focus on dysfunctional schools and call oneself a "change agent," and this bad rap all but disappears. Unfortunately, though, consulting/coaching/mentoring in…

  9. Change Agent Survival Guide

    ERIC Educational Resources Information Center

    Dunbar, Folwell L.

    2011-01-01

    Consulting is a rough racket. Only a tarantula hair above IRS agents, meter maids and used car sales people, the profession is a prickly burr for slings and arrows. Throw in education, focus on dysfunctional schools and call oneself a "change agent," and this bad rap all but disappears. Unfortunately, though, consulting/coaching/mentoring in…

  10. Executing Logical Agent Specifications

    NASA Astrophysics Data System (ADS)

    Fisher, Michael; Hepple, Anthony

    Many agent-oriented programming languages are based on the Prolog like logical goal reduction approach where rules are used to reduce, in a depth-first way, aselected goal. The ability of agents to change between goals means that such languages often overlay the basic computational engine with a mechanism for dynamically changing which goal is selected.

  11. Standard Agent Framework 1

    Energy Science and Technology Software Center (ESTSC)

    1999-04-06

    The Standard Agent framework provides an extensible object-oriented development environment suitable for use in both research and applications projects. The SAF provides a means for constructing and customizing multi-agent systems through specialization of standard base classes (architecture-driven framework) and by composition of component classes (data driven framework). The standard agent system is implemented as an extensible object-centerd framework. Four concrete base classes are developed: (1) Standard Agency; (2) Standard Agent; (3) Human Factor, and (4)more » Resources. The object-centered framework developed and utilized provides the best comprimise between generality and flexibility available in agent development systems today.« less

  12. How do agents represent?

    NASA Astrophysics Data System (ADS)

    Ryan, Alex

    Representation is inherent to the concept of an agent, but its importance in complex systems has not yet been widely recognised. In this paper I introduce Peirce's theory of signs, which facilitates a definition of representation in general. In summary, representation means that for some agent, a model is used to stand in for another entity in a way that shapes the behaviour of the agent with respect to that entity. Representation in general is then related to the theories of representation that have developed within different disciplines. I compare theories of representation from metaphysics, military theory and systems theory. Additional complications arise in explaining the special case of mental representations, which is the focus of cognitive science. I consider the dominant theory of cognition — that the brain is a representational device — as well as the sceptical anti-representational response. Finally, I argue that representation distinguishes agents from non-representational objects: agents are objects capable of representation.

  13. Pediatric Antifungal Agents

    PubMed Central

    Cohen-Wolkowiez, Michael; Moran, Cassandra; Benjamin, Daniel K.; Smith, P Brian

    2009-01-01

    Purpose of review In immunocompromised hosts, invasive fungal infections are common and fatal. In the past decade, the antifungal armamentarium against invasive mycoses has expanded greatly. The purpose of this report is to review the most recent literature addressing the use of antifungal agents in children. Recent findings Most studies evaluating the safety and efficacy of antifungal agents are limited to adults. However, important progress has been made in describing the pharmacokinetics and safety of newer antifungal agents in children, including the echinocandins. Summary Dosage guidelines for newer antifungal agents are currently based on adult and limited pediatric data. Because important developmental pharmacology changes occur throughout childhood impacting the pharmacokinetics of these agents, antifungal studies specifically designed for children are necessary. PMID:19741525

  14. Moral actor, selfish agent.

    PubMed

    Frimer, Jeremy A; Schaefer, Nicola K; Oakes, Harrison

    2014-05-01

    People are motivated to behave selfishly while appearing moral. This tension gives rise to 2 divergently motivated selves. The actor-the watched self-tends to be moral; the agent-the self as executor-tends to be selfish. Three studies present direct evidence of the actor's and agent's distinct motives. To recruit the self-as-actor, we asked people to rate the importance of various goals. To recruit the self-as-agent, we asked people to describe their goals verbally. In Study 1, actors claimed their goals were equally about helping the self and others (viz., moral); agents claimed their goals were primarily about helping the self (viz., selfish). This disparity was evident in both individualist and collectivist cultures, attesting to the universality of the selfish agent. Study 2 compared actors' and agents' motives to those of people role-playing highly prosocial or selfish exemplars. In content (Study 2a) and in the impressions they made on an outside observer (Study 2b), actors' motives were similar to those of the prosocial role-players, whereas agents' motives were similar to those of the selfish role-players. Study 3 accounted for the difference between the actor and agent: Participants claimed that their agent's motives were the more realistic and that their actor's motives were the more idealistic. The selfish agent/moral actor duality may account for why implicit and explicit measures of the same construct diverge, and why feeling watched brings out the better angels of human nature. PMID:24749822

  15. Crystallization and tile separation in the multi-agent systems

    NASA Astrophysics Data System (ADS)

    Collet, Jacques Henri; Fanchon, Jean

    2015-10-01

    This paper deals with the self-organization of simple mobile agents confined in a two-dimension rectangular area. Each agent interacts with its neighbors inside an interaction disk and moves following various types of force-driven couplings (e.g. repulsion or attraction). The agents do not know their absolute position, do not exchange messages, have no memory, and no learning capabilities. We first study the self-organization appearing in systems made-up with one sole type of agents, initially generated at random in the terrain. By changing the agent-agent repulsive interaction, we observe five different population reorganizations, namely, grouping, diffusion (that is classical), but especially interesting, crystallization (i.e., the agents group together on the vertices a regular hexagonal lattice), alignment along straight lines, and vortex dynamics. Then, we consider reorganization in systems made-up from two to five types of agents, where each pair of agent types has specific interaction parameters. The main result of this work is to show that, by only changing the agent-agent repulsion rules, one can generate hexagonal or rectangular multi-agent crystals or on the contrary, induce complete separation in regular hexagonal tiles.

  16. Joint chemical agent detector (JCAD): the future of chemical agent detection

    NASA Astrophysics Data System (ADS)

    Laljer, Charles E.

    2003-08-01

    The Joint Chemical Agent Detector (JCAD) has continued development through 2002. The JCAD has completed Contractor Validation Testing (CVT) that included chemical warfare agent testing, environmental testing, electromagnetic interferent testing, and platform integration validation. The JCAD provides state of the art chemical warfare agent detection capability to military and homeland security operators. Intelligence sources estimate that over twenty countries have active chemical weapons programs. The spread of weapons of mass destruction (and the industrial capability for manufacture of these weapons) to third world nations and terrorist organizations has greatly increased the chemical agent threat to U.S. interests. Coupled with the potential for U.S. involvement in localized conflicts in an operational or support capacity, increases the probability that the military Joint Services may encounter chemical agents anywhere in the world. The JCAD is a small (45 in3), lightweight (2 lb.) chemical agent detector for vehicle interiors, aircraft, individual personnel, shipboard, and fixed site locations. The system provides a common detection component across multi-service platforms. This common detector system will allow the Joint Services to use the same operational and support concept for more efficient utilization of resources. The JCAD detects, identifies, quantifies, and warns of the presence of chemical agents prior to onset of miosis. Upon detection of chemical agents, the detector provides local and remote audible and visual alarms to the operators. Advance warning will provide the vehicle crew and other personnel in the local area with the time necessary to protect themselves from the lethal effects of chemical agents. The JCAD is capable of being upgraded to protect against future chemical agent threats. The JCAD provides the operator with the warning necessary to survive and fight in a chemical warfare agent threat environment.

  17. Biological warfare agents.

    PubMed

    Thavaselvam, Duraipandian; Vijayaraghavan, Rajagopalan

    2010-07-01

    The recent bioterrorist attacks using anthrax spores have emphasized the need to detect and decontaminate critical facilities in the shortest possible time. There has been a remarkable progress in the detection, protection and decontamination of biological warfare agents as many instrumentation platforms and detection methodologies are developed and commissioned. Even then the threat of biological warfare agents and their use in bioterrorist attacks still remain a leading cause of global concern. Furthermore in the past decade there have been threats due to the emerging new diseases and also the re-emergence of old diseases and development of antimicrobial resistance and spread to new geographical regions. The preparedness against these agents need complete knowledge about the disease, better research and training facilities, diagnostic facilities and improved public health system. This review on the biological warfare agents will provide information on the biological warfare agents, their mode of transmission and spread and also the detection systems available to detect them. In addition the current information on the availability of commercially available and developing technologies against biological warfare agents has also been discussed. The risk that arise due to the use of these agents in warfare or bioterrorism related scenario can be mitigated with the availability of improved detection technologies. PMID:21829313

  18. Biological warfare agents

    PubMed Central

    Thavaselvam, Duraipandian; Vijayaraghavan, Rajagopalan

    2010-01-01

    The recent bioterrorist attacks using anthrax spores have emphasized the need to detect and decontaminate critical facilities in the shortest possible time. There has been a remarkable progress in the detection, protection and decontamination of biological warfare agents as many instrumentation platforms and detection methodologies are developed and commissioned. Even then the threat of biological warfare agents and their use in bioterrorist attacks still remain a leading cause of global concern. Furthermore in the past decade there have been threats due to the emerging new diseases and also the re-emergence of old diseases and development of antimicrobial resistance and spread to new geographical regions. The preparedness against these agents need complete knowledge about the disease, better research and training facilities, diagnostic facilities and improved public health system. This review on the biological warfare agents will provide information on the biological warfare agents, their mode of transmission and spread and also the detection systems available to detect them. In addition the current information on the availability of commercially available and developing technologies against biological warfare agents has also been discussed. The risk that arise due to the use of these agents in warfare or bioterrorism related scenario can be mitigated with the availability of improved detection technologies. PMID:21829313

  19. Dioxin, agent orange

    SciTech Connect

    Gough, M.

    1986-01-01

    This book presents information on the following topics: dioxin, a prevalent problem; nobody wanted dioxin; agent organe and Vietnam; what we know about and may learn about agent orange and Veterans' health; agent organe and birth defects; dioxin in Missouri; 2, 4, 5-T: the U.S.' disappearing herbicide; Seveso: high-level environmental exposure; the nitro explosion; industrial exposures to dioxin; company behavior in the face of dioxin exposures; dioxin and specific cancers; animal tests of dioxin toxicity; dioxin decions; the present and the future.

  20. Novel Phenylethynyl Imide Silanes as Coupling Agents for Titanium Alloy

    NASA Technical Reports Server (NTRS)

    Park, C.; Lowther, S. E.; Smith, J. G., Jr.; Conell, J. W.; Hergenrother, P. M.; SaintClair, T. L.

    2004-01-01

    The durability of titanium (Ti) alloys bonded with high temperature adhesives such as polyimides has failed to attain the level of performance required for many applications. The problem to a large part is attributed to the instability of the surface treatment on the Ti substrate. Although Ti alloy adhesive specimens with surface treatments such as chromic acid anodization, Pasa-Jell, Turco, etc. have provided high initial mechanical properties, these properties have decreased as a function of aging at ambient temperature and faster, when aged at elevated temperatures or in a hot-wet environment. As part of the High Speed Civil Transport program where Ti honeycomb sandwich structure must perform for 60,000 hours at 177 C, work was directed to the development of environmentally safe, durable Ti alloy surface treatments.

  1. Agent oriented programming

    NASA Technical Reports Server (NTRS)

    Shoham, Yoav

    1994-01-01

    The goal of our research is a methodology for creating robust software in distributed and dynamic environments. The approach taken is to endow software objects with explicit information about one another, to have them interact through a commitment mechanism, and to equip them with a speech-acty communication language. System-level applications include software interoperation and compositionality. A government application of specific interest is an infrastructure for coordination among multiple planners. Daily activity applications include personal software assistants, such as programmable email, scheduling, and new group agents. Research topics include definition of mental state of agents, design of agent languages as well as interpreters for those languages, and mechanisms for coordination within agent societies such as artificial social laws and conventions.

  2. Cardiovascular and related agents.

    PubMed

    Mátyus, P

    2001-10-01

    Research activities of the Hungarian Institute of Drug Research in the field of cardiovascular agents are reviewed. Many promising drug candidates were found including a compound already marketed. Novel concepts for drug research were developed as well. PMID:11686092

  3. Common chemical agent threats.

    PubMed

    McCafferty, Randall R; Lennarson, Peter J

    2002-03-15

    The events of September 11, 2001, highlight the fact that we live in precarious times. National and global awareness of the resolve and capabilities of terrorists has increased. The possibility that the civilian neurosurgeon may confront a scenario involving the use of chemical warfare agents has heightened. The information reported in this paper serves as a primer on the recognition, decontamination, and treatment of trauma patients exposed to chemical warfare agents. PMID:16212313

  4. Tubular Coupling

    NASA Technical Reports Server (NTRS)

    Rosenbaum, Bernard J. (Inventor)

    2000-01-01

    A system for coupling a vascular overflow graft or cannula to a heart pump. A pump pipe outlet is provided with an external tapered surface which receives the end of a compressible connula. An annular compression ring with a tapered internal bore surface is arranged about the cannula with the tapered internal surface in a facing relationship to the external tapered surface. The angle of inclination of the tapered surfaces is converging such that the spacing between the tapered surfaces decreases from one end of the external tapered surface to the other end thereby providing a clamping action of the tapered surface on a cannula which increases as a function of the length of cannula segment between the tapered surfaces. The annular compression ring is disposed within a tubular locking nut which threadedly couples to the pump and provides a compression force for urging the annular ring onto the cannula between the tapered surfaces. The nut has a threaded connection to the pump body. The threaded coupling to the pump body provides a compression force for the annular ring. The annular ring has an annular enclosure space in which excess cannula material from the compression between the tapered surfaces to "bunch up" in the space and serve as an enlarged annular ring segment to assist holding the cannula in place. The clamped cannula provides a seamless joint connection to the pump pipe outlet where the clamping force is uniformly applied to the cannula because of self alignment of the tapered surfaces. The nut can be easily disconnected to replace the pump if necessary.

  5. Sealing coupling

    DOEpatents

    Pardini, John A. (Brookfield, IL); Brubaker, Robert C. (Naperville, IL); Rusnak, John J. (Orland Park, IL)

    1985-01-01

    Disclosed is a remotely operable releasable sealing coupling which provides fluid-tight joinder of upper and a lower conduit sections. Each conduit section has a concave conical sealing surface adjacent its end portion. A tubular sleeve having convex spherical ends is inserted between the conduit ends to form line contact with the concave conical end portions. An inwardly projecting lip located at one end of the sleeve cooperates with a retaining collar formed on the upper pipe end to provide swivel capture for the sleeve. The upper conduit section also includes a tapered lower end portion which engages the inside surface of the sleeve to limit misalignment of the connected conduit sections.

  6. Agent amplified communication

    SciTech Connect

    Kautz, H.; Selman, B.; Milewski, A.

    1996-12-31

    We propose an agent-based framework for assisting and simplifying person-to-person communication for information gathering tasks. As an example, we focus on locating experts for any specified topic. In our approach, the informal person-to-person networks that exist within an organization are used to {open_quotes}referral chain{close_quotes} requests for expertise. User-agents help automate this process. The agents generate referrals by analyzing records of e-mail communication patterns. Simulation results show that the higher responsiveness of an agent-based system can be effectively traded for the higher accuracy of a completely manual approach. Furthermore, preliminary experience with a group of users on a prototype system has shown that useful automatic referrals can be found in practice. Our experience with actual users has also shown that privacy concerns are central to the successful deployment of personal agents: an advanced agent-based system will therefore need to reason about issues involving trust and authority.

  7. Decoupling Coupled Constraints Through Utility Design

    SciTech Connect

    Li, N; Marden, JR

    2014-08-01

    Several multiagent systems exemplify the need for establishing distributed control laws that ensure the resulting agents' collective behavior satisfies a given coupled constraint. This technical note focuses on the design of such control laws through a game-theoretic framework. In particular, this technical note provides two systematic methodologies for the design of local agent objective functions that guarantee all resulting Nash equilibria optimize the system level objective while also satisfying a given coupled constraint. Furthermore, the designed local agent objective functions fit into the framework of state based potential games. Consequently, one can appeal to existing results in game-theoretic learning to derive a distributed process that guarantees the agents will reach such an equilibrium.

  8. Joint Chemical Agent Detector (JCAD): the future of chemical agent detection

    NASA Astrophysics Data System (ADS)

    Laljer, Charles E.; Owen, Jeffery L.

    2002-06-01

    The Joint Chemical Agent Detector (JCAD) will provide state of the art chemical warfare agent detection capability to ground vehicle operators. Intelligence sources estimate that over twenty counties have active chemical weapons programs. The spread of chemical weapons to third world nations, coupled with the potential for US involvement in these areas in an operational or support capacity, increases the probability that the Joint Services may encounter chemical agents and toxic industrial materials anywhere in the world. Currently, fielded chemical agent detectors are bulky, labor intensive, and subject to false readings. No legacy detector is sensitive enough to provide detection and warning of the low dose hazards associated with miosis contamination. The JCAD will provide a small, lightweight chemical agent detector for vehicle interiors, aircraft, individual personnel, shipboard, and fixed site locations. The system provides a common detection components across multi-service platforms. This common detector system will allow the Joint Services to use the same operational and support concept for more efficient utilization of resources. The JCAD will detect, identify, quantify, and warn of the presence of chemical agents prior to onset of miosis. Upon detection of chemical agents, the detector will provide local and remote audible and visual alarms to the operators. Advance warning will provide the vehicle crew with the time necessary to protect themselves from the lethal effects of chemical agents. The JCAD will also be capable of being upgraded to protect against future chemical agent threats. The JCAD will provide the vehicle operators with the warning necessary to survive and fight in a chemical warfare agent threat environment.

  9. Tangleproof Coupling

    NASA Astrophysics Data System (ADS)

    1987-01-01

    Along with Marshall Space Flight Center, Phase 2 Automation developed a unique rotary coupling capable of connecting a large number of electrical cables to a turntable without stressing the cables or tangling them. Device accommodates 246 cables and allows the turntable to rotate through an arc of 320 degrees. At extremes of rotation the cables remain loose enough so that they are not pulled taut and overstressed; a halfway rotation, the cables are not so loose that they tangle. The rotary connector was developed to carry electrical signals to and from a telescope platform on the satellite without employing a complex set of slip rings which are electrically noisy and could have caused signal interference.

  10. Thermoacoustic couple

    DOEpatents

    Wheatley, J.C.; Swift, G.W.; Migliori, A.

    1983-10-04

    An apparatus and method for determining acoustic power density level and its direction in a fluid using a single sensor are disclosed. The preferred embodiment of the apparatus, which is termed a thermoacoustic couple, consists of a stack of thin, spaced apart polymeric plates, selected ones of which include multiple bimetallic thermocouple junctions positioned along opposite end edges thereof. The thermocouple junctions are connected in series in the nature of a thermopile, and are arranged so as to be responsive to small temperature differences between the opposite edges of the plates. The magnitude of the temperature difference, as represented by the magnitude of the electrical potential difference generated by the thermopile, is found to be directly related to the level of acoustic power density in the gas.

  11. Dark coupling

    SciTech Connect

    Gavela, M.B.; Hernández, D.; Honorez, L. Lopez; Mena, O.; Rigolin, S. E-mail: d.hernandez@uam.es E-mail: omena@ific.uv.es

    2009-07-01

    The two dark sectors of the universe—dark matter and dark energy—may interact with each other. Background and linear density perturbation evolution equations are developed for a generic coupling. We then establish the general conditions necessary to obtain models free from non-adiabatic instabilities. As an application, we consider a viable universe in which the interaction strength is proportional to the dark energy density. The scenario does not exhibit ''phantom crossing'' and is free from instabilities, including early ones. A sizeable interaction strength is compatible with combined WMAP, HST, SN, LSS and H(z) data. Neutrino mass and/or cosmic curvature are allowed to be larger than in non-interacting models. Our analysis sheds light as well on unstable scenarios previously proposed.

  12. Systemic photoprotective agents.

    PubMed

    Black, H S

    1987-08-01

    The concept of an effective, safe systemic photoprotectant circumvents many of the shortcomings associated with the use of topical agents as a modality preventive of actinic damage. On the other hand, difficulties resulting from systemic metabolism and toxicity complicate this approach. The problems are exemplified by the fact that some agents such as the antimalarials, psoralens, and carotenoids have been successfully employed in the treatment of specific photosensitive diseases but, aside from any potential toxicities, their ameliorative effects appear to be related to the particular pathomechanisms of the responding disease rather than general photoprotection. The complexity of systemic approaches is further demonstrated by the fact that agents possessing protective properties, e.g. butylated hydroxytoluene and carotenoids, inhibit UV carcinogenesis, while others, e.g., 8-methoxypsoralen, potentiate this process. Nevertheless, from this ostensible disorder of responses, it seems apparent that those agents holding the greatest promise for future investigation are those capable of enhancing natural defense mechanisms, i.e., melanization and antiradical activity. Thus, while none of the agents reviewed here are deemed suitable as general photoprotectants, the fact that only a modest, measured protective effect can elicit a dramatic decrease in actinic damage (particularly with respect to cancer) upholds this concept as an important goal. PMID:3324073

  13. Current topics in ultrasound contrast agent application and design

    NASA Astrophysics Data System (ADS)

    Allen, John S.; Kruse, Dustin E.; May, Donovan J.

    2001-05-01

    Ultrasound contrast agents are bubbles, 1-10 microns in radius, encapsulated by a lipid, protein, polymer or fluid shell. The agents have been used to distinguish the acoustic scattering signatures of blood from those of the surrounding tissue. This is possible due to the nonlinear response of the agent, which is similar to that of a free gas bubble. Upon sufficient forcing the agents will oscillate nonlinearly about their equilibrium radius, and for specific conditions, produce nonlinear resonance responses which are integer multiples of the primary resonance. Ultrasound tissue perfusion studies have been developed which are based on the destruction of contract agents coupled to the measurement of blood flow. Nevertheless, many outstanding issues remain in contrast agent design especially with respect to emerging applications. Even with the use of higher order harmonics there is a lack of an acoustic signature or destruction mechanism at frequencies above approximately 5.0 MHz with conventional agents. The design and use of a high frequency contrast agent is addressed by exploiting the multiple scattering response of agents modled as spherical elastic shells. Also considered is the nonlinear response of elastic-shelled agents. The considerations of shells modeled as linear and nonlinear elastic materials are discussed. The use of contrast agents for targeted drug delivery has recently received much attention. More specifically, the ImaRx Corporation (Tucson, Arizona) has developed thick fluid shelled agents, which release suspended taxol-based drugs from their shells upon destruction. Shape instabilities and surface waves correspond with the fragmentation and destruction of the agents. Finally, the interaction of multiple contrast agents has received little attention with respect to these emerging applications.

  14. Gadofullerene MRI contrast agents.

    PubMed

    Bolskar, Robert D

    2008-04-01

    A promising new class of MRI contrast-enhancing agents with high relaxivities is based on gadolinium-containing metallofullerenes, which are also termed gadofullerenes. Detailed study of the water-proton relaxivity properties and intermolecular nanoclustering behavior of gadofullerene derivatives has revealed valuable information about their relaxivity mechanisms and given a deeper understanding of this new class of paramagnetic contrast agent. Here, the latest findings on water-solubilized gadofullerene materials and how these findings relate to their future applications in MRI are reviewed and discussed. PMID:18373426

  15. MpcAgent

    Energy Science and Technology Software Center (ESTSC)

    2013-11-29

    MpcAgent software is a module for the VolltronLite platform from PNNL that regulates the operation of rooftop air conditioning units in small to medium commercial buildings for the purpose of reducing peak power consumption. The MpcAgent accomplishes this by restricting the number of units that may operate simultaneously and using a model predictive control strategy to select which units to operate in each control period. The outcome of this control is effective control of themore » building air temperature at the user specified set point while avoiding expensive peak demand charges that result from running all HVAC units simultaneously.« less

  16. MpcAgent

    SciTech Connect

    2013-11-29

    MpcAgent software is a module for the VolltronLite platform from PNNL that regulates the operation of rooftop air conditioning units in small to medium commercial buildings for the purpose of reducing peak power consumption. The MpcAgent accomplishes this by restricting the number of units that may operate simultaneously and using a model predictive control strategy to select which units to operate in each control period. The outcome of this control is effective control of the building air temperature at the user specified set point while avoiding expensive peak demand charges that result from running all HVAC units simultaneously.

  17. Model Checking Normative Agent Organisations

    NASA Astrophysics Data System (ADS)

    Dennis, Louise; Tinnemeier, Nick; Meyer, John-Jules

    We present the integration of a normative programming language in the MCAPL framework for model checking multi-agent systems. The result is a framework facilitating the implementation and verification of multi-agent systems coordinated via a normative organisation. The organisation can be programmed in the normative language while the constituent agents may be implemented in a number of (BDI) agent programming languages.

  18. Hydraulic fracturing propping agent

    SciTech Connect

    Lunghofer, E. P.

    1985-06-11

    A high strength propping agent for use in hydraulic fracturing of subterranean formations comprising solid, spherical particles having an alumina content of between 40 and 60%, a density of less than 3.0 gm/cc and an ambient temperature permeability of 100,000 or more millidarcies at 10,000 psi.

  19. Remote Agent Experiment

    NASA Technical Reports Server (NTRS)

    Benard, Doug; Dorais, Gregory A.; Gamble, Ed; Kanefsky, Bob; Kurien, James; Millar, William; Muscettola, Nicola; Nayak, Pandu; Rouquette, Nicolas; Rajan, Kanna; Norvig, Peter (Technical Monitor)

    2000-01-01

    Remote Agent (RA) is a model-based, reusable artificial intelligence (At) software system that enables goal-based spacecraft commanding and robust fault recovery. RA was flight validated during an experiment on board of DS1 between May 17th and May 21th, 1999.

  20. Battlefield agent collaboration

    NASA Astrophysics Data System (ADS)

    Budulas, Peter P.; Young, Stuart H.; Emmerman, Philip J.

    2001-09-01

    Small air and ground physical agents (robots) will be ubiquitous on the battlefield of the 21st century, principally to lower the exposure to harm of our ground forces in urban and open terrain scenarios. Teams of small collaborating physical agents conducting tasks such as Reconnaissance, Surveillance, and Target Acquisition (RSTA), intelligence, chemical and biological agent detection, logistics, decoy, sentry; and communications relay will have advanced sensors, communications, and mobility characteristics. It is anticipated that there will be many levels of individual and team collaboration between the soldier and robot, robot to robot, and robot to mother ship. This paper presents applications and infrastructure components that illustrate each of these levels. As an example, consider the application where a team of twenty small robots must rapidly explore and define a building complex. Local interactions and decisions require peer to peer collaboration. Global direction and information fusion warrant a central team control provided by a mother ship. The mother ship must effectively deliver/retrieve, service, and control these robots as well as fuse the information gathered by these highly mobile robot teams. Any level of collaboration requires robust communications, specifically a mobile ad hoc network. The application of fixed ground sensors and mobile robots is also included in this paper. This paper discusses on going research at the U.S. Army Research Laboratory that supports the development of multi-robot collaboration. This research includes battlefield visualization, intelligent software agents, adaptive communications, sensor and information fusion, and multi-modal human computer interaction.

  1. Validating the Autonomous Science Agent

    NASA Technical Reports Server (NTRS)

    Chien, Steve; Cichy, Benjamin; Schaffer, Steve; Tran, Danny; Rabideau, Gregg; Sherwood, Rob; Bote, Robert; Mandl, Dan; Frye, Stu; Shulman, Seth; Van Gaasbeck, Jim; Boyer, Darrell

    2003-01-01

    This paper describes the validation process for the Autonomous Science Agent, a software agent that will fly onboard the EO-1 spacecraft from 2003-2004. This agent will recognize science events, retarget the spacecraft to respond to the science events, and reduce data downlink to only the highest value science data. The autonomous science agent has been designed using a layered architectural approach with specific redundant safeguards to reduce the risk of an agent malfunction to the EO-1 spacecraft. This 'safe' design is also in the process of being thoroughly validated by informal validation methods and extensive testing. This paper describes the analysis used to define agent safety, elements of the design that increase the safety of the agent, and the process being used to validate agent safety prior to the agent software controlling the spacecraft.

  2. Ubiquitous Intelligence in Agent Mining

    NASA Astrophysics Data System (ADS)

    Cao, Longbing; Luo, Dan; Zhang, Chengqi

    Agent mining, namely the interaction and integration of multi-agent and data mining, has emerged as a very promising research area. While many mutual issues exist in both multi-agent and data mining areas, most of them can be described in terms of or related to ubiquitous intelligence. It is certainly very important to define, specify, represent, analyze and utilize ubiquitous intelligence in agents, data mining, and agent mining. This paper presents a novel but preliminary investigation of ubiquitous intelligence in these areas. We specify five types of ubiquitous intelligence: data intelligence, human intelligence, domain intelligence, network and web intelligence, organizational intelligence, and social intelligence. We define and illustrate them, and discuss techniques for involving them into agents, data mining, and agent mining for complex problem-solving. Further investigation on involving and synthesizing ubiquitous intelligence into agents, data mining, and agent mining will lead to a disciplinary upgrade from methodological, technical and practical perspectives.

  3. Rigid bifunctional chelating agents

    DOEpatents

    Sweet, M.P.; Mease, R.C.; Srivastava, S.C.

    1998-07-21

    Bicyclo[2.2.2] octane-2,3 diamine-N,N,N`,N`-tetraacetic acids (BODTA) and bicyclo[2.2.1] heptane-2,3 diamine-N,N,N`,N`-tetraacetic acid (BHDTA) are chelating agents useful in forming detectably labeled bioconjugate compounds for diagnostic and therapeutic purposes. New compounds and processes of forming BODTA and BHDTA are disclosed. Radioimmunoconjugates of the present invention show high and prolonged tumor uptake with low normal tissue uptakes.

  4. Surface polymerization agents

    SciTech Connect

    Taylor, C.; Wilkerson, C.

    1996-12-01

    This is the final report of a 1-year, Laboratory-Directed R&D project at LANL. A joint technical demonstration was proposed between US Army Missile Command (Redstone Arsenal) and LANL. Objective was to demonstrate that an unmanned vehicle or missile could be used as a platform to deliver a surface polymerization agent in such a manner as to obstruct the filters of an air-breathing mechanism, resulting in operational failure.

  5. Rigid bifunctional chelating agents

    DOEpatents

    Sweet, Mark P. (Coram, NY); Mease, Ronnie C. (Fairfax, VA); Srivastava, Suresh C. (Setauket, NY)

    2000-02-08

    Bicyclo[2.2.2]octane-2,3 diamine-N,N,N',N'-tetraacetic acids (BODTA) and bicyclo[2.2.1]heptane-2,3 diamine-N,N,N',N'-tetraacetic acid (BHDTA) are chelating agents useful in forming detectably labeled bioconjugate compounds for diagnostic and therapeutic purposes. New compounds and processes of forming BODTA and BHDTA are disclosed. Radioimmunoconjugates of the present invention show high and prolonged tumor uptake with low normal tissue uptakes.

  6. Rigid bifunctional chelating agents

    DOEpatents

    Sweet, Mark P. (Coram, NY); Mease, Ronnie C. (Fairfax, VA); Srivastava, Suresh C. (Setauket, NY)

    1998-07-21

    Bicyclo›2.2.2! octane-2,3 diamine-N,N,N',N'-tetraacetic acids (BODTA) and bicyclo›2.2.1! heptane-2,3 diamine-N,N,N',N'-tetraacetic acid (BHDTA) are chelating agents useful in forming detectably labeled bioconjugate compounds for diagnostic and therapeutic purposes. New compounds and processes of forming BODTA and BHDTA are disclosed. Radioimmunoconjugates of the present invention show high and prolonged tumor uptake with low normal tissue uptakes.

  7. Artificial economic agents

    NASA Astrophysics Data System (ADS)

    Terna, Pietro

    1992-09-01

    Neural networks are able to emulate economic subjects' behavior, without the utilization of a priori economic laws. This work states the possibility of explaining economic regularities about demand curve following connectionist models. Targets for training are generated by the model itself while it learns and acts with a cross-target method, i.e., the artificial neural network produces guesses both of the actions of the economic subject and of their effects. Actual effects are estimated by economic environment rules and results are used to train the effect guess mechanism; the evaluation of actions necessary to match guessed effects are, on the contrary, employed to train the decision mechanism (which guesses actions). Two kinds of learning -- short term and long term learning -- take place. The former only with local capability to react to the changes of the environment and the latter one with full capability to do it. For an observer the behavior produced by this kind of artificial agent (AA) matches the actions of a real agent as stated in economic handbooks, with goals and plans. Obviously, AA has no such symbolic entities, which are inventions of the observer. The assumption is that the observations of economists about real world agents' behavior suffer from the same bias. Economic regularities arising from present versions of the model encourage further developments, in particular toward the interaction of micro-models to build macroeconomic ones.

  8. Peripheral Neuropathy and Agent Orange

    MedlinePLUS

    ... Toll Free Numbers VA » Health Care » Public Health » Military Exposures » Agent Orange » Veterans' Diseases Associated with Agent ... Health Menu Menu Public Health Public Health Home Military Exposures Military Exposures Home 4 Ways to Find ...

  9. AL Amyloidosis and Agent Orange

    MedlinePLUS

    ... Toll Free Numbers VA » Health Care » Public Health » Military Exposures » Agent Orange » Veterans' Diseases Associated with Agent ... Health Menu Menu Public Health Public Health Home Military Exposures Military Exposures Home 4 Ways to Find ...

  10. Coupling coefficients for coupled-cavity lasers

    SciTech Connect

    Lang, R.J.; Yariv, A.

    1987-03-01

    The authors derive simple, analytic formulas for the field coupling coefficients in a two-section coupled-cavity laser using a local field rate equation treatment. They show that there is a correction to the heuristic formulas based on power flow calculated by Marcuse; the correction is in agreement with numerical calculations from a coupled-mode approach.

  11. 13 CFR 108.1620 - Functions of agents, including Central Registration Agent, Selling Agent and Fiscal Agent.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... financial markets to determine those factors that will minimize or reduce the cost of funding Debentures... Assistance SMALL BUSINESS ADMINISTRATION NEW MARKETS VENTURE CAPITAL (âNMVCâ) PROGRAM SBA Financial...) Agents. SBA may appoint or cause to be appointed agent(s) to perform functions necessary to market...

  12. Hydroxypyridonate and hydroxypyrimidinone chelating agents

    SciTech Connect

    Raymond, Kenneth N.; Doble, Daniel M.; Sunderland, Christopher J.; Thompson, Marlon

    2005-01-25

    The present invention provides hydroxypyridinone and hydroxypyrimidone chelating agents. Also provides are Gd(III) complexes of these agents, which are useful as contrast enhancing agents for magnetic resonance imaging. The invention also provides methods of preparing the compounds of the invention, as well as methods of using the compounds in magnetic resonance imaging applications.

  13. Chemical warfare agents

    PubMed Central

    Ganesan, K.; Raza, S. K.; Vijayaraghavan, R.

    2010-01-01

    Among the Weapons of Mass Destruction, chemical warfare (CW) is probably one of the most brutal created by mankind in comparison with biological and nuclear warfare. Chemical weapons are inexpensive and are relatively easy to produce, even by small terrorist groups, to create mass casualties with small quantities. The characteristics of various CW agents, general information relevant to current physical as well as medical protection methods, detection equipment available and decontamination techniques are discussed in this review article. A brief note on Chemical Weapons Convention is also provided. PMID:21829312

  14. DCTD — Featured Agents

    Cancer.gov

    Tandutinib (MLN518), previously known as CT53518, is a small-molecule inhibitor of the type III receptor tyrosine kinases, including the Fms-like tyrosine kinase 3 receptor (FLT3), platelet-derived growth factor receptor (PDGFR), and c-Kit receptor tyrosine kinase. Tandutinib is relatively selective, having no appreciable activity against EGFR, FGFR, KDR, or several non-receptor kinases. FLT3, c-Kit, and ßPDGFR are equally inhibited by tandutinib, while the agent is much less active against CSF-1R (in vitro IC50 of 3.4 µM).

  15. Pharmacologic agents targeting autophagy

    PubMed Central

    Vakifahmetoglu-Norberg, Helin; Xia, Hong-guang; Yuan, Junying

    2015-01-01

    Autophagy is an important intracellular catabolic mechanism critically involved in regulating tissue homeostasis. The implication of autophagy in human diseases and the need to understand its regulatory mechanisms in mammalian cells have stimulated research efforts that led to the development of high-throughput screening protocols and small-molecule modulators that can activate or inhibit autophagy. Herein we review the current landscape in the development of screening technology as well as the molecules and pharmacologic agents targeting the regulatory mechanisms of autophagy. We also evaluate the potential therapeutic application of these compounds in different human pathologies. PMID:25654545

  16. Retinoids as chemopreventive agents.

    PubMed

    Ralhan, R; Kaur, J

    2003-01-01

    Retinoids are promising agents for cancer chemoprevention. The myriad effects of retinoids on biological processes including development, differentiation, homeostasis, carcinogenesis and apoptosis are mediated through their molecular targets, the retinoid and rexinoid receptors. Tissue specific expression patterns, ligand specificities, receptor numbers, their distinct functions and functional redundancy make retinoid signaling highly complex. The cross-talks of these receptors with cell surface receptors signaling pathways, as well as their interactions with multiple co-activators and co-repressors further add to the complexity of the pleiotropic effects of retinoids. Elucidation of retinoid signaling pathways and indepth understanding of the mechanisms that underlie the anti-proliferative and apoptotic action of retinoids has paved the way for designing synthetic retinoids for effective chemoprevention and therapy of cancer. Development of receptor selective synthetic retinoids is a major focus of molecular retinoid development. Other new avenues encompass identification of novel retinoid regulated genes, orphan-receptor ligands/functions, novel retinoid mechanisms involving receptor-independent apoptosis inducing activity and synergistic combinations with other agents for cancer prevention and therapy. This review focuses on recent advances in the understanding of molecular mechanisms underlying the action of retinoids and retinoid molecular targeting studies designed primarily to develop retinoids with reduced toxicity, while maintaining or enhancing activity in context of chemoprevention. The clinical efficacy of retinoid based chemoprevention trials is discussed. PMID:12757022

  17. Holograms as Teaching Agents

    NASA Astrophysics Data System (ADS)

    Walker, Robin A.

    2013-02-01

    Hungarian physicist Dennis Gabor won the Pulitzer Prize for his 1947 introduction of basic holographic principles, but it was not until the invention of the laser in 1960 that research scientists, physicians, technologists and the general public began to seriously consider the interdisciplinary potentiality of holography. Questions around whether and when Three-Dimensional (3-D) images and systems would impact American entertainment and the arts would be answered before educators, instructional designers and students would discover how much Three-Dimensional Hologram Technology (3DHT) would affect teaching practices and learning environments. In the following International Symposium on Display Holograms (ISDH) poster presentation, the author features a traditional board game as well as a reflection hologram to illustrate conventional and evolving Three-Dimensional representations and technology for education. Using elements from the American children's toy Operation® (Hasbro, 2005) as well as a reflection hologram of a human brain (Ko, 1998), this poster design highlights the pedagogical effects of 3-D images, games and systems on learning science. As teaching agents, holograms can be considered substitutes for real objects, (human beings, organs, and animated characters) as well as agents (pedagogical, avatars, reflective) in various learning environments using many systems (direct, emergent, augmented reality) and electronic tools (cellphones, computers, tablets, television). In order to understand the particular importance of utilizing holography in school, clinical and public settings, the author identifies advantages and benefits of using 3-D images and technology as instructional tools.

  18. [New agents for hypercholesterolemia].

    PubMed

    Pintó, Xavier; García Gómez, María Carmen

    2016-02-19

    An elevated proportion of high cardiovascular risk patients do not achieve the therapeutic c-LDL goals. This owes to physicians' inappropriate or insufficient use of cholesterol lowering medications or to patients' bad tolerance or therapeutic compliance. Another cause is an insufficient efficacy of current cholesterol lowering drugs including statins and ezetimibe. In addition, proprotein convertase subtilisin kexin type 9 inhibitors are a new cholesterol lowering medications showing safety and high efficacy to reduce c-LDL in numerous already performed or underway clinical trials, potentially allowing an optimal control of hypercholesterolemia in most patients. Agents inhibiting apolipoprotein B synthesis and microsomal transfer protein are also providing a new potential to decrease cholesterol in patients with severe hypercholesterolemia and in particular in homozygote familial hypercholesterolemia. Last, cholesteryl ester transfer protein inhibitors have shown powerful effects on c-HDL and c-LDL, although their efficacy in cardiovascular prevention and safety has not been demonstrated yet. We provide in this article an overview of the main characteristics of therapeutic agents for hypercholesterolemia, which have been recently approved or in an advanced research stage. PMID:25817449

  19. Model Checking Agent Communication

    NASA Astrophysics Data System (ADS)

    Bentahar, J.; Meyer, J.-J. Ch.; Wan, W.

    Model checking is a formal and automatic technique used to verify computational systems (e.g. communication protocols) against given properties. The purpose of this chapter is to describe a model checking algorithm to verify communication protocols used by autonomous agents interacting using dialogue games, which are governed by a set of logical rules. We use a variant of Extended Computation Tree Logic CTL* for specifying these dialogue games and the properties to be checked. This logic, called ACTL*, extends CTL* by allowing formulae to constrain actions as well as states. The verification method uses an on-the-fly efficient algorithm. It is based on translating formulae into a variant of alternating tree automata called Alternating Büchi Tableau Automata (ABTA). We present a tableau-based version of this algorithm and provide the soundness, completeness, termination and complexity results. Two case studies are discussed along with their respective implementations to illustrate the proposed approach. The first one is about an agent-based negotiation protocol and the second one considers a modified version of the NetBill protocol.

  20. Agents for cerebral edema.

    PubMed

    de los Reyes, R A; Ausman, J I; Diaz, F G

    1981-01-01

    Hyperventilation, ventricular drainage, and mannitol remain the mainstays of the treatment of cerebral edema not amenable to or following surgical therapy. There appears to be good therapeutic rationale for the use of "low-dose" mannitol in more prolonged treatment of intracranial hypertension (Table 5.1). The beneficial effects of steroids, either in "standard" or "high" doses, is less clear but, pending evidence to the contrary, we favor the use of "high-dose" corticosteroid therapy. Barbiturates appear to hold promise, but pending controlled, randomized trials to confirm or refute their efficacy, the logistics of their use, as well as their potential complications, precludes their widespread use outside of major centers. Certainly, the "ideal" agent for the treatment of cerebral edema, one that would selectively mobilize and/or prevent the formation of edema fluid with a rapid onset and prolonged duration of action, and with minimal side effects, remains to be discovered. In the meantime, research to refine the use of the older agents and determine the usefulness of the newer ones should be encouraged. PMID:6797771

  1. Lipid-lowering agents.

    PubMed

    Ewang-Emukowhate, Mfon; Wierzbicki, Anthony S

    2013-09-01

    The role of lipid lowering in reducing the risk of mortality and morbidity from cardiovascular disease (CVD) is well established. Treatment particularly aimed at decreasing low-density lipoprotein cholesterol (LDL-C) is effective in reducing the risk of death from coronary heart disease and stroke. Statins form the cornerstone of treatment. However, in some individuals with a high risk of CVD who are unable to achieve their target LDL-C due to either intolerance or lack of efficacy, there is the need for alternative therapies. This review provides an overview of the different classes of currently available lipid-lowering medications including statins, fibrates, bile acid sequestrants (resins), and omega-3 fatty acids. Data are presented on their indications, pharmacology, and the relevant end point clinical trial data with these drugs. It also discusses the human trial data on some novel therapeutic agents that are being developed including those for homozygous familial hypercholesterolemia--the antisense oligonucleotide mipomersen and the microsomal transfer protein inhibitor lomitapide. Data are presented on phase II and III trials on agents with potentially wider applications, cholesterol ester transfer protein inhibitors and proprotein convertase subtilisin kexin 9 inhibitors. The data on a licensed gene therapy for lipoprotein lipase deficiency are also presented. PMID:23811423

  2. REMOTE BIOSENSOR FOR IN SITU MONITORING OF ORGANOPHOSPHATE NERVE AGENTS. (R823663)

    EPA Science Inventory

    A remote electrochemical biosensor for field monitoring of organophosphate nerve agents is described. The new sensor relies on the coupling of the effective biocatalytic action of organophosphorus hydrolase (OPH) with a submersible amperometric probe design. This combination resu...

  3. Learning models of intelligent agents

    SciTech Connect

    Carmel, D.; Markovitch, S.

    1996-12-31

    Agents that operate in a multi-agent system need an efficient strategy to handle their encounters with other agents involved. Searching for an optimal interactive strategy is a hard problem because it depends mostly on the behavior of the others. In this work, interaction among agents is represented as a repeated two-player game, where the agents` objective is to look for a strategy that maximizes their expected sum of rewards in the game. We assume that agents` strategies can be modeled as finite automata. A model-based approach is presented as a possible method for learning an effective interactive strategy. First, we describe how an agent should find an optimal strategy against a given model. Second, we present an unsupervised algorithm that infers a model of the opponent`s automaton from its input/output behavior. A set of experiments that show the potential merit of the algorithm is reported as well.

  4. Flexible, secure agent development framework

    DOEpatents

    Goldsmith; Steven Y. (Rochester, MN)

    2009-04-07

    While an agent generator is generating an intelligent agent, it can also evaluate the data processing platform on which it is executing, in order to assess a risk factor associated with operation of the agent generator on the data processing platform. The agent generator can retrieve from a location external to the data processing platform an open site that is configurable by the user, and load the open site into an agent substrate, thereby creating a development agent with code development capabilities. While an intelligent agent is executing a functional program on a data processing platform, it can also evaluate the data processing platform to assess a risk factor associated with performing the data processing function on the data processing platform.

  5. Fluoroquinolone antimicrobial agents.

    PubMed Central

    Wolfson, J S; Hooper, D C

    1989-01-01

    The fluoroquinolones, a new class of potent orally absorbed antimicrobial agents, are reviewed, considering structure, mechanisms of action and resistance, spectrum, variables affecting activity in vitro, pharmacokinetic properties, clinical efficacy, emergence of resistance, and tolerability. The primary bacterial target is the enzyme deoxyribonucleic acid gyrase. Bacterial resistance occurs by chromosomal mutations altering deoxyribonucleic acid gyrase and decreasing drug permeation. The drugs are bactericidal and potent in vitro against members of the family Enterobacteriaceae, Haemophilus spp., and Neisseria spp., have good activity against Pseudomonas aeruginosa and staphylococci, and (with several exceptions) are less potent against streptococci and have fair to poor activity against anaerobic species. Potency in vitro decreases in the presence of low pH, magnesium ions, or urine but is little affected by different media, increased inoculum, or serum. The effects of the drugs in combination with a beta-lactam or aminoglycoside are often additive, occasionally synergistic, and rarely antagonistic. The agents are orally absorbed, require at most twice-daily dosing, and achieve high concentrations in urine, feces, and kidney and good concentrations in lung, bone, prostate, and other tissues. The drugs are efficacious in treatment of a variety of bacterial infections, including uncomplicated and complicated urinary tract infections, bacterial gastroenteritis, and gonorrhea, and show promise for therapy of prostatitis, respiratory tract infections, osteomyelitis, and cutaneous infections, particularly when caused by aerobic gram-negative bacilli. Fluoroquinolones have also proved to be efficacious for prophylaxis against travelers' diarrhea and infection with gram-negative bacilli in neutropenic patients. The drugs are effective in eliminating carriage of Neisseria meningitidis. Patient tolerability appears acceptable, with gastrointestinal or central nervous system toxicities occurring most commonly, but only rarely necessitating discontinuance of therapy. In 17 of 18 prospective, randomized, double-blind comparisons with another agent or placebo, fluoroquinolones were tolerated as well as or better than the comparison regimen. Bacterial resistance has been uncommonly documented but occurs, most notably with P. aeruginosa and Staphylococcus aureus and occasionally other species for which the therapeutic ratio is less favorable. Fluoroquinolones offer an efficacious, well-tolerated, and cost-effective alternative to parenteral therapies of selected infections. PMID:2680058

  6. CATS-based Air Traffic Controller Agents

    NASA Technical Reports Server (NTRS)

    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-in-the-loop simulations are unquestionably valuable for this purpose, but pose considerable logistical, fiscal, and experimental control problems. First, data analysis is extremely complicated, owing simply to the large number of participants and data sources in such simulations. In addition, experienced human air traffic controllers working adjacent sectors tend to flexibly adapt to the evolving control problem - potentially shifting to other strategies than those under investigation. In addition, their performance is tightly coupled to the control interface, which in the development phase may support some concepts and supporting strategies better than others. A simple shift in strategy by one controller can change the character of a particular traffic scenario dramatically, which makes experimental comparison of ATC performance under different traffic scenarios difficult. Training a given team of controllers on operations under a new ATM concept for a sufficient period of time could avert such difficulties, but instituting an adequate training program is expensive and logistically difficult.

  7. Desferrithiocin Analogue Uranium Decorporation Agents

    PubMed Central

    Bergeron, Raymond J.; Wiegand, Jan; Singh, Shailendra

    2010-01-01

    Purpose Previous systematic structure-activity studies of the desferrithiocin (DFT) platform have allowed the design and synthesis of analogues and derivatives of DFT that retain the exceptional iron-clearing activity of the parent, while eliminating its adverse effects. We hypothesized that a similar approach could be adopted to identify DFT-related analogues that could effectively decorporate uranium. Materials and Methods The decorporation properties of nine DFT-related analogues were determined in a bile duct-cannulated rat model. Diethylenetriaminepentaacetic acid (DTPA) served as a positive control. Selected ligands also underwent multiple and delayed dosing regimens. Uranium excretion in urine and bile or stool was determined by inductively coupled plasma mass spectroscopy (ICP-MS); tissue levels of uranium were also assessed. Results The two best clinical candidates are (S)-4,5-dihydro-2-[2-hydroxy-4-(3,6,9-trioxadecyloxy)phenyl]-4-methyl-4-thiazolecarboxylic acid [(S)-4'-(HO)-DADFT-PE (9)], with a 57% reduction in kidney uranium levels on oral (p.o.) administration and (S)-4,5-dihydro-2-[2-hydroxy-3-(3,6,9-trioxadecyloxy)phenyl]-4-methyl-4-thiazolecarboxylic acid [(S)-3'-(HO)-DADFT-PE (10)], with a 62% renal reduction on p.o. administration. The majority of the metal excretion promoted by these analogues is in the bile, thus further reducing kidney actinide exposure. Conclusions While 9 administered p.o. or subcutaneously (s.c.) immediately post-metal is an effective decorporation agent, withholding the dose (s.c.) until 4 h reduced the activity of the compound. Conversion of 9 to its isopropyl ester may circumvent this issue. PMID:19399680

  8. Newer Hemostatic Agents.

    PubMed

    Franchini, Massimo; Favaloro, Emmanuel J; Lippi, Giuseppe

    2015-10-01

    The mainstay of treatment of inherited coagulation disorders is based on the infusion of the deficient clotting factor, when available. Significant advances have been made over the past two decades in the production and availability of factor replacement products. In spite of such progression, several issue are still unsolved, the most important being the need for frequent factor concentrate infusions and the development of inhibitory alloantibodies. To overcome these important limitations, several newer hemostatic agents with an extended half-life are at an advanced stage of clinical development. After a brief overview of hemostasis, this narrative review summarizes the current knowledge on the most promising novel products for hemostasis. The current status of gene therapy for hemophilia, the only therapeutic option to definitively cure this inherited bleeding disorder, is also concisely discussed. PMID:25893779

  9. Hepatocytes as Immunological Agents.

    PubMed

    Crispe, Ian N

    2016-01-01

    Hepatocytes are targeted for infection by a number of major human pathogens, including hepatitis B virus, hepatitis C virus, and malaria. However, hepatocytes are also immunological agents in their own right. In systemic immunity, they are central in the acute-phase response, which floods the circulation with defensive proteins during diverse stresses, including ischemia, physical trauma, and sepsis. Hepatocytes express a variety of innate immune receptors and, when challenged with pathogen- or damage-associated molecular patterns, can deliver cell-autonomous innate immune responses that may result in host defense or in immunopathology. Important human pathogens have evolved mechanisms to subvert these responses. Finally, hepatocytes talk directly to T cells, resulting in a bias toward immune tolerance. PMID:26685314

  10. Peptide Antimicrobial Agents

    PubMed Central

    Jenssen, HÃ¥vard; Hamill, Pamela; Hancock, Robert E. W.

    2006-01-01

    Antimicrobial host defense peptides are produced by all complex organisms as well as some microbes and have diverse and complex antimicrobial activities. Collectively these peptides demonstrate a broad range of antiviral and antibacterial activities and modes of action, and it is important to distinguish between direct microbicidal and indirect activities against such pathogens. The structural requirements of peptides for antiviral and antibacterial activities are evaluated in light of the diverse set of primary and secondary structures described for host defense peptides. Peptides with antifungal and antiparasitic activities are discussed in less detail, although the broad-spectrum activities of such peptides indicate that they are important host defense molecules. Knowledge regarding the relationship between peptide structure and function as well as their mechanism of action is being applied in the design of antimicrobial peptide variants as potential novel therapeutic agents. PMID:16847082

  11. [Unconventional antidiabetic agents].

    PubMed

    Rustenbeck, Ingo

    2007-04-01

    The current pharmacological therapy of type 2 diabetes reduces the risk of diabetic complications, but is not able to achieve a long-lasting normalization of the metabolic disorder. Thus diabetic patients in increasing numbers are taking dietary supplements and herbs from which they expect additional health benefits. These unconventional antidiabetic agents consist mainly in trace metals like chromium, vanadium and zinc and a heterogeneous group of traditionally used antidiabetic herbs (e. g. Momordica charantia, Gymnema sylvestre, Trigonella foenum-graecum) often derived from the ayurvedic medicine. In this overview the current evidence for the antidiabetic effect is presented. The trace elements chromium and vanadium have a number of potentially antidiabetic actions in vitro, however, the results obtained with diabetic patients are not convincing so far. Similarly, the available data on the therapeutic use of herbs suggest that in principle a number of them possess a blood glucose-lowering effect, but at present no firm conclusions as to their efficacy and safety can be made. To set up reliable dose-effect relationships requires the identification of the relevant antidiabetic molecules as was apparently achieved by isolating 4-hydroxyisoleucine from the seeds of T. foenum-graecum. This requirement is also valid in the case of the antidiabetic action of cinnamon. Coffee and a moderate alcohol consumption were found to be surprisingly effective in lowering the risk of type 2 diabetes manifestation, their effect being roughly equal to that of conventional drugs used in diabetes prevention trials. Diabetic patients should inform their physician about the use of unconventional agents and should be warned against uncontrolled starting or stopping their use. PMID:17484443

  12. Second-order cluster consensus of multi-agent dynamical systems with impulsive effects

    NASA Astrophysics Data System (ADS)

    Wang, Guan; Shen, Yi

    2014-09-01

    This paper discuss the cluster consensus of multi-agent dynamical systems (MADSs) with impulsive effects and coupling delays. Some sufficient conditions that guarantee cluster consensus in MADS are derived. In each cluster, agents update their position and velocity states according to a leader's instantaneous information, and interactions among agents are uncertain. Furthermore, switching topology problem in MADS is considered by impulsive stability and adaptive strategy. Finally, numerical simulations are given to verify our theoretical analysis.

  13. The value of less connected agents in Boolean networks

    NASA Astrophysics Data System (ADS)

    Epstein, Daniel; Bazzan, Ana L. C.

    2013-11-01

    In multiagent systems, agents often face binary decisions where one seeks to take either the minority or the majority side. Examples are minority and congestion games in general, i.e., situations that require coordination among the agents in order to depict efficient decisions. In minority games such as the El Farol Bar Problem, previous works have shown that agents may reach appropriate levels of coordination, mostly by looking at the history of past decisions. Not many works consider any kind of structure of the social network, i.e., how agents are connected. Moreover, when structure is indeed considered, it assumes some kind of random network with a given, fixed connectivity degree. The present paper departs from the conventional approach in some ways. First, it considers more realistic network topologies, based on preferential attachments. This is especially useful in social networks. Second, the formalism of random Boolean networks is used to help agents to make decisions given their attachments (for example acquaintances). This is coupled with a reinforcement learning mechanism that allows agents to select strategies that are locally and globally efficient. Third, we use agent-based modeling and simulation, a microscopic approach, which allows us to draw conclusions about individuals and/or classes of individuals. Finally, for the sake of illustration we use two different scenarios, namely the El Farol Bar Problem and a binary route choice scenario. With this approach we target systems that adapt dynamically to changes in the environment, including other adaptive decision-makers. Our results using preferential attachments and random Boolean networks are threefold. First we show that an efficient equilibrium can be achieved, provided agents do experimentation. Second, microscopic analysis show that influential agents tend to consider few inputs in their Boolean functions. Third, we have also conducted measurements related to network clustering and centrality that help to see how agents are organized.

  14. Collaborating Fuzzy Reinforcement Learning Agents

    NASA Technical Reports Server (NTRS)

    Berenji, Hamid R.

    1997-01-01

    Earlier, we introduced GARIC-Q, a new method for doing incremental Dynamic Programming using a society of intelligent agents which are controlled at the top level by Fuzzy Relearning and at the local level, each agent learns and operates based on ANTARCTIC, a technique for fuzzy reinforcement learning. In this paper, we show that it is possible for these agents to compete in order to affect the selected control policy but at the same time, they can collaborate while investigating the state space. In this model, the evaluator or the critic learns by observing all the agents behaviors but the control policy changes only based on the behavior of the winning agent also known as the super agent.

  15. Agent-based enterprise integration

    SciTech Connect

    N. M. Berry; C. M. Pancerella

    1998-12-01

    The authors are developing and deploying software agents in an enterprise information architecture such that the agents manage enterprise resources and facilitate user interaction with these resources. The enterprise agents are built on top of a robust software architecture for data exchange and tool integration across heterogeneous hardware and software. The resulting distributed multi-agent system serves as a method of enhancing enterprises in the following ways: providing users with knowledge about enterprise resources and applications; accessing the dynamically changing enterprise; locating enterprise applications and services; and improving search capabilities for applications and data. Furthermore, agents can access non-agents (i.e., databases and tools) through the enterprise framework. The ultimate target of the effort is the user; they are attempting to increase user productivity in the enterprise. This paper describes their design and early implementation and discusses the planned future work.

  16. Agent-based enterprise integration

    SciTech Connect

    N. M. Berry; C. M. Pancerella

    1999-05-01

    The authors are developing and deploying software agents in an enterprise information architecture such that the agents manage enterprise resources and facilitate user interaction with these resources. Their enterprise agents are built on top of a robust software architecture for data exchange and tool integration across heterogeneous hardware and software. The resulting distributed multi-agent system serves as a method of enhancing enterprises in the following ways: providing users with knowledge about enterprise resources and applications; accessing the dynamically changing enterprise; intelligently locating enterprise applications and services; and improving search capabilities for applications and data. Furthermore, agents can access non-agents (i.e., databases and tools) through the enterprise framework. The ultimate target of their effort is the user; they are attempting to increase user productivity in the enterprise. This paper describes their design and early implementation and discusses their planned future work.

  17. Nerve Agent Toxicity and Treatment.

    PubMed

    Holstege, Christopher P; Dobmeier, Stephen G

    2005-03-01

    The clinical syndrome of nerve agent toxicity varies widely, ranging from the classic cholinergic syndrome to flaccid paralysis and status epilepticus. All nerve agents are capable of producing marked neuropathology. Seizure control is strongly associated with protection against acute lethality and brain pathology. The mainstays of therapy of nerve agent poisoned patients are atropine, pralidoxime, and benzodiazepines. Fosphenytoin provides little therapeutic anticonvulsant effectiveness for nerve agent-induced status epilepticus. Tachycardia is not a contraindication to treatment with atropine in nerve agent toxicity. Atropine should be administered to alleviate respiratory distress, symptomatic bradycardia, and as an adjunct to benzodiazepines and pralidoxime to alleviate seizure activity. In significant nerve agent toxicity, a continuous pralidoxime infusion may be considered. PMID:15676112

  18. Programming Organization-Aware Agents

    NASA Astrophysics Data System (ADS)

    van Riemsdijk, M. Birna; Hindriks, Koen; Jonker, Catholijn

    Organizational notions such as roles, norms (e.g., obligations and permissions), and services are increasingly viewed as natural concepts to manage the complexity of software development. In particular in the context of multi-agent systems, agents are expected to be organization-aware, i.e., to understand and reason about the structure, work processes, and norms of the agent organization in which they operate. In this paper, we analyze which kinds of reasoning an agent should be able to do to function in an organization. We categorize these kinds of reasoning with respect to several dimensions, and distinguish three general approaches on how these might be integrated in existing agent programming languages. Through this, we provide a research agenda on what needs to be addressed when developing techniques for programming organization-aware agents.

  19. Radioactive scanning agents with stabilizer

    SciTech Connect

    Fawzi, M.B.

    1980-11-04

    Stable compositions, useful as technetium-99m-based scintigraphic agents, comprise gentisyl alcohol or a pharmaceutically-acceptable salt or ester thereof in combination with a pertechnetate reducing agent or dissolved in pertechnetate -99m (99mtco4-) solution. The compositions are especially useful in combination with a phosphate or phosphonate material which carries the radionuclide to bone, thus providing a skeletal imaging agent.

  20. Broad-spectrum antiviral agents

    PubMed Central

    Zhu, Jun-Da; Meng, Wen; Wang, Xiao-Jia; Wang, Hwa-Chain R.

    2015-01-01

    Development of highly effective, broad-spectrum antiviral agents is the major objective shared by the fields of virology and pharmaceutics. Antiviral drug development has focused on targeting viral entry and replication, as well as modulating cellular defense system. High throughput screening of molecules, genetic engineering of peptides, and functional screening of agents have identified promising candidates for development of optimal broad-spectrum antiviral agents to intervene in viral infection and control viral epidemics. This review discusses current knowledge, prospective applications, opportunities, and challenges in the development of broad-spectrum antiviral agents. PMID:26052325

  1. Incorporating BDI Agents into Human-Agent Decision Making Research

    NASA Astrophysics Data System (ADS)

    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.

  2. Plasmids encoding therapeutic agents

    DOEpatents

    Keener, William K.

    2007-08-07

    Plasmids encoding anti-HIV and anti-anthrax therapeutic agents are disclosed. Plasmid pWKK-500 encodes a fusion protein containing DP178 as a targeting moiety, the ricin A chain, an HIV protease cleavable linker, and a truncated ricin B chain. N-terminal extensions of the fusion protein include the maltose binding protein and a Factor Xa protease site. C-terminal extensions include a hydrophobic linker, an L domain motif peptide, a KDEL ER retention signal, another Factor Xa protease site, an out-of-frame buforin II coding sequence, the lacZ.alpha. peptide, and a polyhistidine tag. More than twenty derivatives of plasmid pWKK-500 are described. Plasmids pWKK-700 and pWKK-800 are similar to pWKK-500 wherein the DP178-encoding sequence is substituted by RANTES- and SDF-1-encoding sequences, respectively. Plasmid pWKK-900 is similar to pWKK-500 wherein the HIV protease cleavable linker is substituted by a lethal factor (LF) peptide-cleavable linker.

  3. 7 CFR 4290.1620 - Functions of agents, including Central Registration Agent, Selling Agent and Fiscal Agent.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... to: (i) Establish performance criteria for Poolers. (ii) Monitor and evaluate the financial markets..., DEPARTMENT OF AGRICULTURE RURAL BUSINESS INVESTMENT COMPANY (âRBICâ) PROGRAM Financial Assistance for RBICs... or cause to be appointed agent(s) to perform functions necessary to market and service Debentures...

  4. 13 CFR 107.1620 - Functions of agents, including Central Registration Agent, Selling Agent and Fiscal Agent.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... markets to determine those factors that will minimize or reduce the cost of funding Debentures or... Assistance SMALL BUSINESS ADMINISTRATION SMALL BUSINESS INVESTMENT COMPANIES SBA Financial Assistance for... will appoint or cause to be appointed agent(s) to perform functions necessary to market and...

  5. Agent-Based Literacy Theory

    ERIC Educational Resources Information Center

    McEneaney, John E.

    2006-01-01

    The purpose of this theoretical essay is to explore the limits of traditional conceptualizations of reader and text and to propose a more general theory based on the concept of a literacy agent. The proposed theoretical perspective subsumes concepts from traditional theory and aims to account for literacy online. The agent-based literacy theory…

  6. Normative Multi-Agent Organizations

    NASA Astrophysics Data System (ADS)

    Dastani, Mehdi

    Multi-agent systems are viewed as consisting of individual agents whose behaviors are regulated by organization artifacts. This abstract presents a programming language, which is designed to implement norm-based organization artifacts, by means of an example and explains the execution behavior of the language interpreter.

  7. Bioresponsive, Cell-Penetrating and Multimeric MR Contrast Agents

    PubMed Central

    Major, Jody L.; Meade, Thomas J.

    2009-01-01

    Conspectus Magnetic resonance imaging (MRI) has become increasingly popular in molecular imaging and clinical radiology because it is non-invasive and capable of producing three-dimensional representations of opaque organisms with high spatial and temporal resolution. While approximately 35% of all clinical MR scans utilize contrast media, a primary limitation of MR imaging is the low sensitivity to detect contrast agents requiring high concentrations of agent for enhanced signal intensity (0.1-0.6 mM).1 A number of strategies have been employed to amplify the observed in vivo signal of MR contrast agents. Approaches include attachment of Gd(III) chelates to polymers, proteins and particles, encapsulation into micelles and caged structures, and targeting to receptors. While each of these approaches has yielded significant increases in the relaxivity of MR contrast agents (and therefore sensitivity), all of these classes of complexes possess intrinsic background signal and function solely as anatomical reporters due to their constitutive activity. In order to reduce the background signal and simultaneously create probes that are modulated by biochemical events, caged complexes were designed to coordinatively saturate the paramagnetic ion. Coupled with amplification strategies, these agents represent a means to selectively modulate the observed MR signal and function as in vivo biochemical reporters. For example, to create an in vivo MR assay of enzymatic activities and secondary messengers, agents have been designed and synthesized with removable protection groups that largely prevent access of water to a paramagnetic center. By limiting the access of bulk water (q-modulation) the unprocessed agent is designed to be an ineffective contrast agent, and hence serves as a reliable marker for regions of enzyme activity or secondary messengers. In this Account we describe our results toward designing new classes of MR agents that are i. responsive to in vivo physiological or biochemical events ii. cell-permeable to increase local concentration, and iii. attached to large molecules or are synthesized with multiply labeled conjugates for signal amplification. PMID:19537782

  8. Transdermal delivery of therapeutic agent

    NASA Technical Reports Server (NTRS)

    Kwiatkowski, Krzysztof C. (Inventor); Hayes, Ryan T. (Inventor); Magnuson, James W. (Inventor); Giletto, Anthony (Inventor)

    2008-01-01

    A device for the transdermal delivery of a therapeutic agent to a biological subject that includes a first electrode comprising a first array of electrically conductive microprojections for providing electrical communication through a skin portion of the subject to a second electrode comprising a second array of electrically conductive microprojections. Additionally, a reservoir for holding the therapeutic agent surrounding the first electrode and a pulse generator for providing an exponential decay pulse between the first and second electrodes may be provided. A method includes the steps of piercing a stratum corneum layer of skin with two arrays of conductive microprojections, encapsulating the therapeutic agent into biocompatible charged carriers, surrounding the conductive microprojections with the therapeutic agent, generating an exponential decay pulse between the two arrays of conductive microprojections to create a non-uniform electrical field and electrokinetically driving the therapeutic agent through the stratum corneum layer of skin.

  9. Markov Tracking for Agent Coordination

    NASA Technical Reports Server (NTRS)

    Washington, Richard; Lau, Sonie (Technical Monitor)

    1998-01-01

    Partially observable Markov decision processes (POMDPs) axe an attractive representation for representing agent behavior, since they capture uncertainty in both the agent's state and its actions. However, finding an optimal policy for POMDPs in general is computationally difficult. In this paper we present Markov Tracking, a restricted problem of coordinating actions with an agent or process represented as a POMDP Because the actions coordinate with the agent rather than influence its behavior, the optimal solution to this problem can be computed locally and quickly. We also demonstrate the use of the technique on sequential POMDPs, which can be used to model a behavior that follows a linear, acyclic trajectory through a series of states. By imposing a "windowing" restriction that restricts the number of possible alternatives considered at any moment to a fixed size, a coordinating action can be calculated in constant time, making this amenable to coordination with complex agents.

  10. Viroids: molecular infectious agents.

    PubMed

    Smarda, J

    1987-11-01

    In 1971, unique small RNA molecules, the viroids, were found to cause specific infectious diseases of plants. They are the smallest and simplest contagious agents known. Until now, 14 viroids have been described and 12 diseases of potatoes, tomatoes, citruses, chrysanthemums, cucumbers, hops, coconut palms avocado trees and burdock are known to be caused by viroids. The common symptoms of these diseases are: stunting of plants. discoloration of veins, epinasty, curling and distortions of leaves, chlorotic or necrotic spots etc., followed by death of the diseased plants. All viroids are ssRNAs of m.w. ranging from 1.1 x 10(5) to 1.7 x 10(5), corresponding to chains of just 246 to 371 ribonucleotides. For 10 viroids, complete nucleotide sequences are known PSTV, CSV, CEV, TPMV and TASV show 60%-80% homology with each other; in analogy, ASBV, HSV, CPFV. GV and CCCV are closely homologous to each other, too, but just distantly related to the PSTV group. Extensive intramolecular base pairing creates a characteristic secondary structure of the cyclic viroid RNA chain, native viroids appearing as quasi double-stranded, unbranched, very short rod-like structures with short single-stranded loops. (Thus PSTV forms rods about 50 nm long and 2 nm wide.) The stretch of nearly all viroids bears a common central conserved region of 19 bp. The "upper" part of this region is, presumably, the cleavage-ligation site of viroid oligomers during replication. Viroids are located and replicated in nuclei of infected cells, in association with their nucleoli. Their replication is directed by host DNA-dependent RNA polymerase II using cRNA oligomers as templates according to the rolling circle model. Viroid RNA has no mRNA function. The virulence of viroids is coded by their virulence modulating region in the "left hand" part of their molecules: a single nucleotide substitution between nucleotides 43 and 56 within this region alters the virulence. Most probably, viroids have originated by the circularization of spliced-out transcripts of eucaryotic introns. A stable complex may be created between the 5' end of U1 snRNA and nucleotides 257 to 279 of PSTV cRNA strand; thus the pathogenic effects of viroids seem to be a result of their interference with pre-mRNA processing. PMID:2449812

  11. Velocity synchronization of multi-agent systems with mismatched parameters via sampled position data

    NASA Astrophysics Data System (ADS)

    Sun, Wen; Huang, Chunli; Lü, Jinhu; Li, Xiong; Chen, Shihua

    2016-02-01

    Power systems are special multi-agent systems with nonlinear coupling function and symmetric structures. This paper extends these systems to a class of multi-agent systems with mismatched parameters, linear coupling function, and asymmetric structures and investigates their velocity synchronization via sampled position data. The dynamics of the agents is adopted as that of generators with mismatched parameters, while the system structures are supposed to be complex. Two distributed linear consensus protocols are designed, respectively, for multi-agent systems without or with communication delay. Necessary and sufficient conditions based on the sampling period, the mismatched parameters, the delay, and the nonzero eigenvalues of the Laplacian matrix are established. It is shown that velocity synchronization of multi-agent systems with mismatched parameters can be achieved if the sampled period is chosen appropriately. Simulations are given to illustrate the effectiveness of the theoretical results.

  12. Velocity synchronization of multi-agent systems with mismatched parameters via sampled position data.

    PubMed

    Sun, Wen; Huang, Chunli; Lü, Jinhu; Li, Xiong; Chen, Shihua

    2016-02-01

    Power systems are special multi-agent systems with nonlinear coupling function and symmetric structures. This paper extends these systems to a class of multi-agent systems with mismatched parameters, linear coupling function, and asymmetric structures and investigates their velocity synchronization via sampled position data. The dynamics of the agents is adopted as that of generators with mismatched parameters, while the system structures are supposed to be complex. Two distributed linear consensus protocols are designed, respectively, for multi-agent systems without or with communication delay. Necessary and sufficient conditions based on the sampling period, the mismatched parameters, the delay, and the nonzero eigenvalues of the Laplacian matrix are established. It is shown that velocity synchronization of multi-agent systems with mismatched parameters can be achieved if the sampled period is chosen appropriately. Simulations are given to illustrate the effectiveness of the theoretical results. PMID:26931587

  13. Agent Model Development for Assessing Climate-Induced Geopolitical Instability.

    SciTech Connect

    Boslough, Mark B.; Backus, George A.

    2005-12-01

    We present the initial stages of development of new agent-based computational methods to generate and test hypotheses about linkages between environmental change and international instability. This report summarizes the first year's effort of an originally proposed three-year Laboratory Directed Research and Development (LDRD) project. The preliminary work focused on a set of simple agent-based models and benefited from lessons learned in previous related projects and case studies of human response to climate change and environmental scarcity. Our approach was to define a qualitative model using extremely simple cellular agent models akin to Lovelock's Daisyworld and Schelling's segregation model. Such models do not require significant computing resources, and users can modify behavior rules to gain insights. One of the difficulties in agent-based modeling is finding the right balance between model simplicity and real-world representation. Our approach was to keep agent behaviors as simple as possible during the development stage (described herein) and to ground them with a realistic geospatial Earth system model in subsequent years. This work is directed toward incorporating projected climate data--including various C02 scenarios from the Intergovernmental Panel on Climate Change (IPCC) Third Assessment Report--and ultimately toward coupling a useful agent-based model to a general circulation model.3

  14. Engineering upconverting nanophosphors as biosensors and biotherapeutic agents

    NASA Astrophysics Data System (ADS)

    Lim, Shuang Fang

    2012-02-01

    Contrast agents play an important role in the study of biological tissues and whole organisms, since they enable visualization of functional structures. Fluorescent contrast agents also enable specific targeting in therapeutic approaches. Developing optimized contrast agents is central to optimizing the performance of both imaging and therapy. Upconversion nanophosphors (UCNPs) are a class of nanoparticles which enable efficient 2-photon fluorescence. Their intrinsic properties of low toxicity, low excitation intensity, narrow fluorescence line width, multiplexing capability, zero fluorescent background, and absence of bleaching and blinking make them strong candidates as a contrast agent with wide applicability. I am working to develop these nanomaterials with biological significance as contrast agents in biolabels , in biosensors and as therapeutic agents in photodynamic therapy. This will be combined with the enhancement of brightness of the UCNPs through coupling to resonant gold nanofeatures. The study is necessary in order to bring about a break through in upconversion luminescence enhancement, particularly at ever decreasing nanoparticle sizes necessary for biological applications.

  15. Surface preparation and coupling in plastic scintillator dosimetry.

    PubMed

    Ayotte, Guylaine; Archambault, Louis; Gingras, Luc; Lacroix, Frédéric; Beddar, A Sam; Beaulieu, Luc

    2006-09-01

    One way to improve the performance of scintillation dosimeters is to increase the light-collection efficiency at the coupling interfaces of the detector system. We performed a detailed study of surface preparation of scintillating fibers and their coupling with clear optical fibers to minimize light loss and increase the amount of light collected. We analyzed fiber-surface polishing with aluminum oxide sheets, coating fibers with magnesium oxide, and the use of eight different coupling agents (air, three optical gels, an optical curing agent, ultraviolet light, cyanoacrylate glue, and acetone). We prepared 10 scintillating fiber and clear optical fiber light guide samples to test different coupling methods. To test the coupling, we first cut both the scintillating fiber and the clear optical fiber. Then, we cleaned and polished both ends of both fibers. Finally, we coupled the scintillating fiber with the clear optical fiber in either a polyethylene jacket or a V-grooved support depending on the coupling agent used. To produce more light, we used an ultraviolet lamp to stimulate scintillation. A typical series of similar couplings showed a standard deviation in light-collection efficiency of 10%. This can be explained by differences in the surface preparation quality and alignment of the scintillating fiber with the clear optical fiber. Absence of surface polishing reduced the light collection by approximately 40%, and application of magnesium oxide on the proximal end of the scintillating fiber increased the amount of light collected from the optical fiber by approximately 39%. Of the coupling agents, we obtained the best results using one of the optical gels. Because a large amount of the light produced inside a scintillator is usually lost, better light-collection efficiency will result in improved sensitivity. PMID:17022248

  16. Surface preparation and coupling in plastic scintillator dosimetry

    SciTech Connect

    Ayotte, Guylaine; Archambault, Louis; Gingras, Luc; Lacroix, Frederic; Beddar, A. Sam; Beaulieu, Luc

    2006-09-15

    One way to improve the performance of scintillation dosimeters is to increase the light-collection efficiency at the coupling interfaces of the detector system. We performed a detailed study of surface preparation of scintillating fibers and their coupling with clear optical fibers to minimize light loss and increase the amount of light collected. We analyzed fiber-surface polishing with aluminum oxide sheets, coating fibers with magnesium oxide, and the use of eight different coupling agents (air, three optical gels, an optical curing agent, ultraviolet light, cyanoacrylate glue, and acetone). We prepared 10 scintillating fiber and clear optical fiber light guide samples to test different coupling methods. To test the coupling, we first cut both the scintillating fiber and the clear optical fiber. Then, we cleaned and polished both ends of both fibers. Finally, we coupled the scintillating fiber with the clear optical fiber in either a polyethylene jacket or a V-grooved support depending on the coupling agent used. To produce more light, we used an ultraviolet lamp to stimulate scintillation. A typical series of similar couplings showed a standard deviation in light-collection efficiency of 10%. This can be explained by differences in the surface preparation quality and alignment of the scintillating fiber with the clear optical fiber. Absence of surface polishing reduced the light collection by approximately 40%, and application of magnesium oxide on the proximal end of the scintillating fiber increased the amount of light collected from the optical fiber by approximately 39%. Of the coupling agents, we obtained the best results using one of the optical gels. Because a large amount of the light produced inside a scintillator is usually lost, better light-collection efficiency will result in improved sensitivity.

  17. Agent Communications using Distributed Metaobjects

    SciTech Connect

    Goldsmith, Steven Y.; Spires, Shannon V.

    1999-06-10

    There are currently two proposed standards for agent communication languages, namely, KQML (Finin, Lobrou, and Mayfield 1994) and the FIPA ACL. Neither standard has yet achieved primacy, and neither has been evaluated extensively in an open environment such as the Internet. It seems prudent therefore to design a general-purpose agent communications facility for new agent architectures that is flexible yet provides an architecture that accepts many different specializations. In this paper we exhibit the salient features of an agent communications architecture based on distributed metaobjects. This architecture captures design commitments at a metaobject level, leaving the base-level design and implementation up to the agent developer. The scope of the metamodel is broad enough to accommodate many different communication protocols, interaction protocols, and knowledge sharing regimes through extensions to the metaobject framework. We conclude that with a powerful distributed object substrate that supports metaobject communications, a general framework can be developed that will effectively enable different approaches to agent communications in the same agent system. We have implemented a KQML-based communications protocol and have several special-purpose interaction protocols under development.

  18. Nuclear magnetic resonance contrast agents

    DOEpatents

    Smith, Paul H. (Los Alamos, NM); Brainard, James R. (Los Alamos, NM); Jarvinen, Gordon D. (Los Alamos, NM); Ryan, Robert R. (Los Alamos, NM)

    1997-01-01

    A family of contrast agents for use in magnetic resonance imaging and a method of enhancing the contrast of magnetic resonance images of an object by incorporating a contrast agent of this invention into the object prior to forming the images or during formation of the images. A contrast agent of this invention is a paramagnetic lanthanide hexaazamacrocyclic molecule, where a basic example has the formula LnC.sub.16 H.sub.14 N.sub.6. Important applications of the invention are in medical diagnosis, treatment, and research, where images of portions of a human body are formed by means of magnetic resonance techniques.

  19. Symptom management for schizophrenic agents

    SciTech Connect

    Sengers, P.

    1996-12-31

    Behavior-based paradigms are a promising avenue towards creating full-blown integrated autonomous agents. However, until now they have had a major stumbling block: programmers can create robust, subtle, and expressive behaviors, but the agent`s overall behavior gradually falls apart as these behaviors are combined. For small numbers of behaviors, this disintegration can be managed by the programmer, but as more behaviors are combined their interactions become so complex that they become at least time-consuming and at worst impossible to manage.

  20. Nuclear magnetic resonance contrast agents

    DOEpatents

    Smith, P.H.; Brainard, J.R.; Jarvinen, G.D.; Ryan, R.R.

    1997-12-30

    A family of contrast agents for use in magnetic resonance imaging and a method of enhancing the contrast of magnetic resonance images of an object by incorporating a contrast agent of this invention into the object prior to forming the images or during formation of the images. A contrast agent of this invention is a paramagnetic lanthanide hexaazamacrocyclic molecule, where a basic example has the formula LnC{sub 16}H{sub 14}N{sub 6}. Important applications of the invention are in medical diagnosis, treatment, and research, where images of portions of a human body are formed by means of magnetic resonance techniques. 10 figs.

  1. Formalization of Embodied Sensorimotor Coupling System

    NASA Astrophysics Data System (ADS)

    Nakajima, Kohei

    2008-10-01

    Theoretical conception of an active behavior of the system is one of the most challengeable topics in complex systems research. Recently, especially in the fields of robotics and artificial intelligence, there broadly exists the study to understand the interface between the system and its environment by creating an autonomous agent that carries a sensorimotor coupling. In this paper, an embodied sensorimotor coupling system is discussed. Applying a generative pointer, the system is formalized to contain an intrinsic discrepancy induced by heterarichical duality in a flow construction by using category theory. In the system, the body plays a positive role as a dynamical mediator, or interface, between two conflicting layers, a relational layers and a constituent layers. As a result, it induces a structural change of the system itself. Implementing the construction to a Braitenberg type vehicle, we observed dynamical changes of system parameters and its behavior revealed various motion patterns compared with the conventional sensorimotor coupling system.

  2. Agents, Bayes, and Climatic Risks - a modular modelling approach

    NASA Astrophysics Data System (ADS)

    Haas, A.; Jaeger, C.

    2005-08-01

    When insurance firms, energy companies, governments, NGOs, and other agents strive to manage climatic risks, it is by no way clear what the aggregate outcome should and will be. As a framework for investigating this subject, we present the LAGOM model family. It is based on modules depicting learning social agents. For managing climate risks, our agents use second order probabilities and update them by means of a Bayesian mechanism while differing in priors and risk aversion. The interactions between these modules and the aggregate outcomes of their actions are implemented using further modules. The software system is implemented as a series of parallel processes using the CIAMn approach. It is possible to couple modules irrespective of the language they are written in, the operating system under which they are run, and the physical location of the machine.

  3. Triggered pore-forming agents

    DOEpatents

    Bayley, Hagan; Walker, Barbara J.; Chang, Chung-yu; Niblack, Brett; Panchal, Rekha

    1998-01-01

    An inactive pore-forming agent which is activated to lytic function by a condition such as pH, light, heat, reducing potential, or metal ion concentration, or substance such as a protease, at the surface of a cell.

  4. Agent-based forward analysis

    SciTech Connect

    Kerekes, Ryan A.; Jiao, Yu; Shankar, Mallikarjun; Potok, Thomas E.; Lusk, Rick M.

    2008-01-01

    We propose software agent-based "forward analysis" for efficient information retrieval in a network of sensing devices. In our approach, processing is pushed to the data at the edge of the network via intelligent software agents rather than pulling data to a central facility for processing. The agents are deployed with a specific query and perform varying levels of analysis of the data, communicating with each other and sending only relevant information back across the network. We demonstrate our concept in the context of face recognition using a wireless test bed comprised of PDA cell phones and laptops. We show that agent-based forward analysis can provide a significant increase in retrieval speed while decreasing bandwidth usage and information overload at the central facility. n

  5. Tissue Penetration of Antifungal Agents

    PubMed Central

    Felton, Timothy; Troke, Peter F.

    2014-01-01

    SUMMARY Understanding the tissue penetration of systemically administered antifungal agents is critical for a proper appreciation of their antifungal efficacy in animals and humans. Both the time course of an antifungal drug and its absolute concentrations within tissues may differ significantly from those observed in the bloodstream. In addition, tissue concentrations must also be interpreted within the context of the pathogenesis of the various invasive fungal infections, which differ significantly. There are major technical obstacles to the estimation of concentrations of antifungal agents in various tissue subcompartments, yet these agents, even those within the same class, may exhibit markedly different tissue distributions. This review explores these issues and provides a summary of tissue concentrations of 11 currently licensed systemic antifungal agents. It also explores the therapeutic implications of their distribution at various sites of infection. PMID:24396137

  6. Launch Commit Criteria Monitoring Agent

    NASA Technical Reports Server (NTRS)

    Semmel, Glenn S.; Davis, Steven R.; Leucht, Kurt W.; Rowe, Dan A.; Kelly, Andrew O.; Boeloeni, Ladislau

    2005-01-01

    The Spaceport Processing Systems Branch at NASA Kennedy Space Center has developed and deployed a software agent to monitor the Space Shuttle's ground processing telemetry stream. The application, the Launch Commit Criteria Monitoring Agent, increases situational awareness for system and hardware engineers during Shuttle launch countdown. The agent provides autonomous monitoring of the telemetry stream, automatically alerts system engineers when predefined criteria have been met, identifies limit warnings and violations of launch commit criteria, aids Shuttle engineers through troubleshooting procedures, and provides additional insight to verify appropriate troubleshooting of problems by contractors. The agent has successfully detected launch commit criteria warnings and violations on a simulated playback data stream. Efficiency and safety are improved through increased automation.

  7. Diamine curing agents for polyurethanes

    NASA Technical Reports Server (NTRS)

    Bell, V. L.; St. Clair, T. L.

    1975-01-01

    Three aromatic diamines have properties that make them promising candidates as curing agents for converting isocyanates to polyurethanes with higher adhesive strengths, higher softening temperatures, better toughness, and improved abrasion resistance.

  8. Handling of injectable antineoplastic agents.

    PubMed Central

    Knowles, R S; Virden, J E

    1980-01-01

    Although the clinical toxicity of antineoplastic drugs has been well documented there is little or no information on the problems that may arise on the handling and mishandling of such agents. This paper attempts to highlight the importance of taking precautions to prevent adverse effects resulting from contact with cytotoxic drugs during handling and to suggest a practical guide for the handling of such agents. PMID:7427382

  9. Bulking agents in sludge composting

    SciTech Connect

    De Bertoldi, M.; Citernesi, U.; Griselli, M.

    1980-01-01

    Composting is one of the most effective ways of disposing of sludge in agriculture. Three bulking agents were studied: (1) the organic fraction of solid wastes, (2) solid agricultural and forestry waste (straw, maize cobs, sawdust, cork, pine cones, etc.), and (3) recyclable inert substrates (polystyrene or polyethylene balls, porous clay balls, etc.). The sole purpose of the inert bulking agent is to aid in the aeration and drying of the composting material.

  10. Novel agents in Waldenstrom Macroglobulinemia

    PubMed Central

    Sacco, Antonio; Leleu, Xavier; Rossi, Giuseppe; Ghobrial, Irene M.; Roccaro, Aldo M.

    2011-01-01

    Waldenström’s Macroglobulinemia (WM) is a B-cell disorder characterized by the infiltration of the bone marrow (BM) with lymphoplasmacytic cells, as well as detection of an IgM monoclonal gammopathy in the serum. WM is considered an incurable disease, with an overall median survival of only 5-6 years. The success of targeted therapy in multiple myeloma (MM) has led to the development and investigation of more than 30 new compounds in this disease and in other plasma cell dyscrasias WM, both in the preclinical settings and as part of clinical trials. Among therapeutical options, first-line therapies have been based on single-agent or combination regimens with alkylator agents, nucleoside analogues, and the monoclonal antibody anti-CD20. Based on the understanding of the complex interaction between tumor cells and bone marrow microenvironment and the signaling pathways that are deregulated in WM pathogenesis, a number of novel therapeutic agents are now available; and demonstrated significant efficacy in WM. The range of the ORR to these novel agents is between 25-80%. Ongoing and planned future clinical trials include those using PKC inhibitors such as enzastaurin, new proteasome inhibitors such as carfilzomib, histone deacetylase inhibitors such as LBH589, humanized CD20 antibodies such as Ofatumumab, and additional alkylating agents such as bendamustine. These agents, when compared to traditional chemotherapeutic agents, may lead in the future to higher responses, longer remissions and better quality of life for patients with WM. This review will mainly focus on those novel agent that entered clinical trial for the treatment of WM. PMID:22844582

  11. Natural products as antimitotic agents.

    PubMed

    Dall'Acqua, Stefano

    2014-01-01

    Natural products still play an important role in the medicinal chemistry, especially in some therapeutic areas. As example more than 60% of currently-used anticancer agents are derives from natural sources including plants, marine organisms or micro-organism. Thus natural products (NP) are an high-impact source of new "lead compounds" or new potential therapeutic agents despite the large development of biotechnology and combinatorial chemistry in the drug discovery and development. Many examples of anticancer drugs as paclitaxel, combretastatin, bryostatin and discodermolide have shown the importance of NP in the anticancer chemotherapy through many years. Many organisms have been studied as sources of drugs namely plants, micro-organisms and marine organisms and the obtained NP can be considered a group of "privileged chemical structures" evolved in nature to interact with other organisms. For this reason NP are a good starting points for pharmaceutical research and also for library design. Tubulin and microtubules are one of the most studied targets for the search of anticancer compounds. Microtubule targeting agents (MTA) also named antimitotic agents are compounds that are able to perturb mitosis but are also able to arrest cell growing during interphase. The anticancer drugs, taxanes and vinca alkaloids have established tubulin as important target in cancer therapy. More recently the vascular disrupting agents (VDA) combretastatin analogues were studied for their antimitotics properties. This review will consider the anti mitotic NP and their potential impact in the development of new therapeutic agents. PMID:25434355

  12. Multiagent Learning of Coordination in Loosely Coupled Multiagent Systems.

    PubMed

    Yu, Chao; Zhang, Minjie; Ren, Fenghui; Tan, Guozhen

    2015-12-01

    Multiagent learning (MAL) is a promising technique for agents to learn efficient coordinated behaviors in multiagent systems (MASs). In MAL, concurrent multiple distributed learning processes can make the learning environment nonstationary for each individual learner. Developing an efficient learning approach to coordinate agents' behaviors in this dynamic environment is a difficult problem, especially when agents do not know the domain structure and have only local observability of the environment. In this paper, a coordinated MAL approach is proposed to enable agents to learn efficient coordinated behaviors by exploiting agent independence in loosely coupled MASs. The main feature of the proposed approach is to explicitly quantify and dynamically adapt agent independence during learning so that agents can make a trade-off between a single-agent learning process and a coordinated learning process for an efficient decision making. The proposed approach is employed to solve two-robot navigation problems in different scales of domains. Experimental results show that agents using the proposed approach can learn to act in concert or independently in different areas of the environment, which results in great computational savings and near optimal performance. PMID:25594993

  13. Three tooth kinematic coupling

    DOEpatents

    Hale, Layton C. (Livermore, CA)

    2000-01-01

    A three tooth kinematic coupling based on having three theoretical line contacts formed by mating teeth rather than six theoretical point contacts. The geometry requires one coupling half to have curved teeth and the other coupling half to have flat teeth. Each coupling half has a relieved center portion which does not effect the kinematics, but in the limit as the face width approaches zero, three line contacts become six point contacts. As a result of having line contact, a three tooth coupling has greater load capacity and stiffness. The kinematic coupling has application for use in precision fixturing for tools or workpieces, and as a registration device for a work or tool changer or for optics in various products.

  14. [Therapy for infertile couples].

    PubMed

    Sperling, H; Eisenhardt, A; Becker, M; Rübben, H

    2005-10-01

    Therapy for infertile couples comprises gender-specific as well as couple-specific aspects. Diagnostic and therapeutic procedures focus on the causes of the infertility such as refertilization or epididymovasostomy on the one hand and assisted fertilization with extracted spermatozoa on the other. Using an interdisciplinary approach including urology, gynecology, reproductive medicine and human genetics, the treating physicians are able to fulfil the desire of infertile couples for a healthy child in many cases. PMID:16167125

  15. Learning in multi-agent systems

    SciTech Connect

    Goldman, C.V.

    1996-12-31

    Learning agents acting in a multi agent environment can improve their performance. These agents might decide upon their course of action by learning about other agents with whom they interact. The learning agents can learn about the others information and rules of behavior. The agents will not need to plan their actions beforehand, each time they are asked to solve the same problem they have already solved or when dealing with similar problems.

  16. A amphoteric copolymer profile modification agent

    SciTech Connect

    Wang HongGuan; Yu LianCheng; Tian HongKun

    1995-11-01

    This report provides a new gel profile modification agent prepared by an amphoteric copolymer (FT-213) and a novel crosslinking agent (BY), and introduces the preparations of the amphoteric polymer, the crosslinking agent and the profile modification agent, the action mechanism, the test conditions and the evaluations of the performance of the agent. The 45 well treatments in oilfields demonstrate that the agent can be prepared conveniently, the agent has better compatibility and application performances, and the treatment life is longer with the use of the agent. 80,000 tons incremental oil and 60,000 m{sup 3} decreasing water production have been achieved.

  17. A multi-agent architecture for geosimulation of moving agents

    NASA Astrophysics Data System (ADS)

    Vahidnia, Mohammad H.; Alesheikh, Ali A.; Alavipanah, Seyed Kazem

    2015-10-01

    In this paper, a novel architecture is proposed in which an axiomatic derivation system in the form of first-order logic facilitates declarative explanation and spatial reasoning. Simulation of environmental perception and interaction between autonomous agents is designed with a geographic belief-desire-intention and a request-inform-query model. The architecture has a complementary quantitative component that supports collaborative planning based on the concept of equilibrium and game theory. This new architecture presents a departure from current best practices geographic agent-based modelling. Implementation tasks are discussed in some detail, as well as scenarios for fleet management and disaster management.

  18. Investigational Antimicrobial Agents of 2013

    PubMed Central

    Pucci, Michael J.

    2013-01-01

    SUMMARY New antimicrobial agents are always needed to counteract the resistant pathogens that continue to be selected by current therapeutic regimens. This review provides a survey of known antimicrobial agents that were currently in clinical development in the fall of 2012 and spring of 2013. Data were collected from published literature primarily from 2010 to 2012, meeting abstracts (2011 to 2012), government websites, and company websites when appropriate. Compared to what was reported in previous surveys, a surprising number of new agents are currently in company pipelines, particularly in phase 3 clinical development. Familiar antibacterial classes of the quinolones, tetracyclines, oxazolidinones, glycopeptides, and cephalosporins are represented by entities with enhanced antimicrobial or pharmacological properties. More importantly, compounds of novel chemical structures targeting bacterial pathways not previously exploited are under development. Some of the most promising compounds include novel β-lactamase inhibitor combinations that target many multidrug-resistant Gram-negative bacteria, a critical medical need. Although new antimicrobial agents will continue to be needed to address increasing antibiotic resistance, there are novel agents in development to tackle at least some of the more worrisome pathogens in the current nosocomial setting. PMID:24092856

  19. Targeted agents in ovarian cancer.

    PubMed

    Kristedja, T S; Morgan, R J; Cristea, M

    2010-09-01

    Despite recent advances in the treatment of ovarian cancer, a large majority of women with this diagnosis will die from recurrence of their disease. Targeted therapies, in the form of monoclonal antibodies and small molecule tyrosine kinase inhibitors have significantly altered the management of many solid tumors and hematologic malignancies. No such agents have been approved by the US FDA for use in ovarian cancer, although Phase II data suggests excellent single-agent activity of some of these drugs. Antiangiogenic agents in combination with chemotherapy are being evaluated in Phase III clinical trials, both in the adjuvant setting and in recurrent platinum-sensitive disease. Poly-ADP-ribose polymerase inhibitors are promising agents in BRCA1/2-mutated breast and ovarian cancers. Ongoing clinical trials are exploring the anti-tumor effect of poly-ADP-ribose polymerase inhibitors administered as single agents and in combination with chemotherapy. Many other new drugs are in earlier grades of development. In this article, we review the state of the art in targeted therapies for ovarian cancer and identify future directions for their development in the management of this often devastating disease. PMID:20887168

  20. Inotropic agents and immune modulation.

    PubMed

    Sasayama, Shigetake

    2002-05-01

    Since depression of myocardial contractility forms the basis for the development of heart failure, many attempts have been made to enhance the inotropic state of the failing heart by cardiotonic agent as the therapeutic modality. However, large scale clinical trials conducted in the Western societies revealed excess mortality in patients with heart failure received long-term treatment with inotropic agent. Therefore, all of these agents are now regarded as unsuitable for chronic heart failure treatment. In contrast, some inotropic agents with phosphodiesterase inhibitory properties exhibited potential benefits in Japanese patients. In Japan mortality due to heart disease is substantially lower than that found in all other Western countries. Thereby, chronic treatment with inotropic agent may be justified as the optimal care in the context of relief of symptoms and an improved quality of life. The salutary effects of these phosphodiesterase inhibitors appear to be related to anticytokine and immunomodulating effects as well as their cardiotonic action. These findings support the recent new concept that immune responses mediated by cytokines play an important role in the pathogenesis of heart failure. PMID:12374902

  1. Next Generation Remote Agent Planner

    NASA Technical Reports Server (NTRS)

    Jonsson, Ari K.; Muscettola, Nicola; Morris, Paul H.; Rajan, Kanna

    1999-01-01

    In May 1999, as part of a unique technology validation experiment onboard the Deep Space One spacecraft, the Remote Agent became the first complete autonomous spacecraft control architecture to run as flight software onboard an active spacecraft. As one of the three components of the architecture, the Remote Agent Planner had the task of laying out the course of action to be taken, which included activities such as turning, thrusting, data gathering, and communicating. Building on the successful approach developed for the Remote Agent Planner, the Next Generation Remote Agent Planner is a completely redesigned and reimplemented version of the planner. The new system provides all the key capabilities of the original planner, while adding functionality, improving performance and providing a modular and extendible implementation. The goal of this ongoing project is to develop a system that provides both a basis for future applications and a framework for further research in the area of autonomous planning for spacecraft. In this article, we present an introductory overview of the Next Generation Remote Agent Planner. We present a new and simplified definition of the planning problem, describe the basics of the planning process, lay out the new system design and examine the functionality of the core reasoning module.

  2. Ring Current Electrodynamic Coupling

    NASA Technical Reports Server (NTRS)

    Khazanov, G. V.

    2004-01-01

    In this talk we will address the two primary issues of ring current (RC) electrodynamic coupling: 1. RC self-consistent coupling with electromagnetic ion cyclotron (EMIC) waves (small scale electrodynamic coupling); and 2. RC self-consistent magnetosphere-ionosphere coupling that includes calculation of the magnetospheric electric field (large scale electrodynamic coupling). Our study will be based on two RC models that we have recently developed in our group. The first model by Khazanov et al. [2002, 20031 couples the system of two kinetic equations: one equation which describes the RC ion dynamics and another equation which describes the energy density evolution of EMIC waves. The second model by Khazanov et al. [2003] deals with large scale electrodynamic coupling processes and provides a self-consistent simulation of RC ions, electrons and the magnetospheric electric field. There is presently no model that addresses both of these issues simultaneously in a self-consistent calculation. However, the need exists for such a model, because these two processes directly influence each other, with the mesoscale coupling changing the drift paths of the thermal and energetic particle populations in the inner magnetosphere, thereby changing the wave interactions, and the microscale coupling altering the pitch angle distributions and ionospheric conductivities (through increased precipitation), thus changing the field-aligned currents and electric potential structure. The initial thrust of the work will be the development of a combined kinetic model of micro- and meso-scale RC electrodynamic coupling processes and to examine their interactions with each other on a global scale. We also discuss the nonlinear coupling of EMIC and lower hybrid waves in the RC region during the May 2-7, 1998 storm period.

  3. Translation-coupling systems

    SciTech Connect

    Pfleger, Brian; Mendez-Perez, Daniel

    2015-05-19

    Disclosed are systems and methods for coupling translation of a target gene to a detectable response gene. A version of the invention includes a translation-coupling cassette. The translation-coupling cassette includes a target gene, a response gene, a response-gene translation control element, and a secondary structure-forming sequence that reversibly forms a secondary structure masking the response-gene translation control element. Masking of the response-gene translation control element inhibits translation of the response gene. Full translation of the target gene results in unfolding of the secondary structure and consequent translation of the response gene. Translation of the target gene is determined by detecting presence of the response-gene protein product. The invention further includes RNA transcripts of the translation-coupling cassettes, vectors comprising the translation-coupling cassettes, hosts comprising the translation-coupling cassettes, methods of using the translation-coupling cassettes, and gene products produced with the translation-coupling cassettes.

  4. Translation-coupling systems

    SciTech Connect

    Pfleger, Brian; Mendez-Perez, Daniel

    2013-11-05

    Disclosed are systems and methods for coupling translation of a target gene to a detectable response gene. A version of the invention includes a translation-coupling cassette. The translation-coupling cassette includes a target gene, a response gene, a response-gene translation control element, and a secondary structure-forming sequence that reversibly forms a secondary structure masking the response-gene translation control element. Masking of the response-gene translation control element inhibits translation of the response gene. Full translation of the target gene results in unfolding of the secondary structure and consequent translation of the response gene. Translation of the target gene is determined by detecting presence of the response-gene protein product. The invention further includes RNA transcripts of the translation-coupling cassettes, vectors comprising the translation-coupling cassettes, hosts comprising the translation-coupling cassettes, methods of using the translation-coupling cassettes, and gene products produced with the translation-coupling cassettes.

  5. Agent review phase one report.

    SciTech Connect

    Zubelewicz, Alex Tadeusz; Davis, Christopher Edward; Bauer, Travis LaDell

    2009-12-01

    This report summarizes the findings for phase one of the agent review and discusses the review methods and results. The phase one review identified a short list of agent systems that would prove most useful in the service architecture of an information management, analysis, and retrieval system. Reviewers evaluated open-source and commercial multi-agent systems and scored them based upon viability, uniqueness, ease of development, ease of deployment, and ease of integration with other products. Based on these criteria, reviewers identified the ten most appropriate systems. The report also mentions several systems that reviewers deemed noteworthy for the ideas they implement, even if those systems are not the best choices for information management purposes.

  6. Polycatechol Nanoparticle MRI Contrast Agents.

    PubMed

    Li, Yiwen; Huang, Yuran; Wang, Zhao; Carniato, Fabio; Xie, Yijun; Patterson, Joseph P; Thompson, Matthew P; Andolina, Christopher M; Ditri, Treffly B; Millstone, Jill E; Figueroa, Joshua S; Rinehart, Jeffrey D; Scadeng, Miriam; Botta, Mauro; Gianneschi, Nathan C

    2016-02-01

    Amphiphilic triblock copolymers containing Fe(III) -catecholate complexes formulated as spherical- or cylindrical-shaped micellar nanoparticles (SMN and CMN, respectively) are described as new T 1 -weighted agents with high relaxivity, low cytotoxicity, and long-term stability in biological fluids. Relaxivities of both SMN and CMN exceed those of established gadolinium chelates across a wide range of magnetic field strengths. Interestingly, shape-dependent behavior is observed in terms of the particles' interactions with HeLa cells, with CMN exhibiting enhanced uptake and contrast via magnetic resonance imaging (MRI) compared with SMN. These results suggest that control over soft nanoparticle shape will provide an avenue for optimization of particle-based contrast agents as biodiagnostics. The polycatechol nanoparticles are proposed as suitable for preclinical investigations into their viability as gadolinium-free, safe, and effective imaging agents for MRI contrast enhancement. PMID:26681255

  7. Adaptive networks of trading agents

    NASA Astrophysics Data System (ADS)

    Burda, Z.; Krzywicki, A.; Martin, O. C.

    2008-10-01

    Multiagent models have been used in many contexts to study generic collective behavior. Similarly, complex networks have become very popular because of the diversity of growth rules giving rise to scale-free behavior. Here we study adaptive networks where the agents trade “wealth” when they are linked together while links can appear and disappear according to the wealth of the corresponding agents; thus the agents influence the network dynamics and vice versa. Our framework generalizes a multiagent model of Bouchaud and Mézard [Physica A 282, 536 (2000)], and leads to a steady state with fluctuating connectivities. The system spontaneously self-organizes into a critical state where the wealth distribution has a fat tail and the network is scale free; in addition, network heterogeneities lead to enhanced wealth condensation.

  8. Dual Rationality and Deliberative Agents

    NASA Astrophysics Data System (ADS)

    Debenham, John; Sierra, Carles

    Human agents deliberate using models based on reason for only a minute proportion of the decisions that they make. In stark contrast, the deliberation of artificial agents is heavily dominated by formal models based on reason such as game theory, decision theory and logic—despite that fact that formal reasoning will not necessarily lead to superior real-world decisions. Further the Nobel Laureate Friedrich Hayek warns us of the ‘fatal conceit’ in controlling deliberative systems using models based on reason as the particular model chosen will then shape the system’s future and either impede, or eventually destroy, the subtle evolutionary processes that are an integral part of human systems and institutions, and are crucial to their evolution and long-term survival. We describe an architecture for artificial agents that is founded on Hayek’s two rationalities and supports the two forms of deliberation used by mankind.

  9. Thyroid Dysfunction from Antineoplastic Agents

    PubMed Central

    Larsen, P. Reed; Marqusee, Ellen

    2011-01-01

    Unlike cytotoxic agents that indiscriminately affect rapidly dividing cells, newer antineoplastic agents such as targeted therapies and immunotherapies are associated with thyroid dysfunction. These include tyrosine kinase inhibitors, bexarotene, radioiodine-based cancer therapies, denileukin diftitox, alemtuzumab, interferon-?, interleukin-2, ipilimumab, tremelimumab, thalidomide, and lenalidomide. Primary hypothyroidism is the most common side effect, although thyrotoxicosis and effects on thyroid-stimulating hormone secretion and thyroid hormone metabolism have also been described. Most agents cause thyroid dysfunction in 20%–50% of patients, although some have even higher rates. Despite this, physicians may overlook drug-induced thyroid dysfunction because of the complexity of the clinical picture in the cancer patient. Symptoms of hypothyroidism, such as fatigue, weakness, depression, memory loss, cold intolerance, and cardiovascular effects, may be incorrectly attributed to the primary disease or to the antineoplastic agent. Underdiagnosis of thyroid dysfunction can have important consequences for cancer patient management. At a minimum, the symptoms will adversely affect the patient’s quality of life. Alternatively, such symptoms can lead to dose reductions of potentially life-saving therapies. Hypothyroidism can also alter the kinetics and clearance of medications, which may lead to undesirable side effects. Thyrotoxicosis can be mistaken for sepsis or a nonendocrinologic drug side effect. In some patients, thyroid disease may indicate a higher likelihood of tumor response to the agent. Both hypothyroidism and thyrotoxicosis are easily diagnosed with inexpensive and specific tests. In many patients, particularly those with hypothyroidism, the treatment is straightforward. We therefore recommend routine testing for thyroid abnormalities in patients receiving these antineoplastic agents. PMID:22010182

  10. The Coupling Controversy

    PubMed Central

    Fox, Peter T.

    2014-01-01

    Functional magnetic resonance imaging (fMRI) relies on the well-known phenomenon of coupling between neuronal activity and brain blood flow. For nearly a century, the presumption was that hemodynamics were coupled to neuronal activity via energy demand and oxidative metabolism. Early 15O positron-emission tomographic (PET) studies challenged this theory, demonstrating a physiological “uncoupling” between brain blood flow and oxygen metabolism. These PET observations played a pivotal role in guiding the development of fMRI, by demonstrating which physiological parameters were most closely coupled to neuronal activity and by presaging the BOLD-contrast effect. Subsequent PET studies were crucial for constraining theories concerning the physiological mechanisms underlying hemodynamic/neuronal coupling and, thereby, guiding the development of models for quantification of oxygen metabolic rate %? from fMRI. A first-person account of the PET “coupling” studies and their influence on the development of fMRI is provided. PMID:22306802

  11. Exponentially modified QCD coupling

    SciTech Connect

    Cvetic, Gorazd; Valenzuela, Cristian

    2008-04-01

    We present a specific class of models for an infrared-finite analytic QCD coupling, such that at large spacelike energy scales the coupling differs from the perturbative one by less than any inverse power of the energy scale. This condition is motivated by the Institute for Theoretical and Experimental Physics operator product expansion philosophy. Allowed by the ambiguity in the analytization of the perturbative coupling, the proposed class of couplings has three parameters. In the intermediate energy region, the proposed coupling has low loop-level and renormalization scheme dependence. The present modification of perturbative QCD must be considered as a phenomenological attempt, with the aim of enlarging the applicability range of the theory of the strong interactions at low energies.

  12. Coupled nano-plasmons

    NASA Astrophysics Data System (ADS)

    Apostol, M.; Ilie, S.; Petrut, A.; Savu, M.; Toba, S.

    2014-05-01

    A simple model of coupled plasmons arising in two neighbouring nano-particles is presented. The coupled oscillations and the corresponding eigenfrequencies are computed. It is shown that the plasmons may be periodically transferred between the two particles. For larger separation distances between the two particles the retardation is included. The oscillation eigenmodes are the polaritons in this case. There are distances for which the particles do not couple to each other, i.e. the polaritonic coupling gets damped. The van der Waals-London-Casimir force is estimated for the two particles; it is shown that for large distances the force is repulsive. We compute also the polarizabilities of the two coupled nano-particles and their cross-section under the action of an external monochromatic plane wave, which exhibit resonances indicative of light trapping and field enhancement. A resonant force is also identified, acting upon the particles both on behalf of the external field and of each other.

  13. Autonomous sensor manager agents (ASMA)

    NASA Astrophysics Data System (ADS)

    Osadciw, Lisa A.

    2004-04-01

    Autonomous sensor manager agents are presented as an algorithm to perform sensor management within a multisensor fusion network. The design of the hybrid ant system/particle swarm agents is described in detail with some insight into their performance. Although the algorithm is designed for the general sensor management problem, a simulation example involving 2 radar systems is presented. Algorithmic parameters are determined by the size of the region covered by the sensor network, the number of sensors, and the number of parameters to be selected. With straight forward modifications, this algorithm can be adapted for most sensor management problems.

  14. [Therapeutic agents for osteoporotic pain].

    PubMed

    Nakao, Shin-Ichi; Miyamoto, Erabu; Kawakami, Mamoru

    2015-10-01

    Low back pain (LBP) is one of the major symptoms of elderly patients with osteoporosis. Pain control is important because pain hinders quality of life. The pathogenesis of the osteoporosis-related LBP is divided as follows, (1) vertebral fracture with bone fragility, (2) imbalance of sagittal alignment, (3) osteoporotic bone pain, (4) reduction of the descending pain inhibition system of serotonine, (5) psychological condition, (6) neural pain. For the treatment of osteoporosis-related LBP, there are two types of medicine. One is a medicine for osteoporosis with an analgetic action, another is an analgetic agent. In this chapter, we explained various analgetic agents for osteoporosis-related LBP. PMID:26529934

  15. 7 CFR 58.629 - Flavoring agents.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... Material § 58.629 Flavoring agents. Flavoring agents either natural or artificial shall be wholesome and... 7 Agriculture 3 2013-01-01 2013-01-01 false Flavoring agents. 58.629 Section 58.629 Agriculture.... Flavoring agents shall be one or more of those approved in § 58.605....

  16. 7 CFR 58.629 - Flavoring agents.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... Material § 58.629 Flavoring agents. Flavoring agents either natural or artificial shall be wholesome and... 7 Agriculture 3 2014-01-01 2014-01-01 false Flavoring agents. 58.629 Section 58.629 Agriculture.... Flavoring agents shall be one or more of those approved in § 58.605....

  17. Clustering recommendations to compute agent reputation

    NASA Astrophysics Data System (ADS)

    Bedi, Punam; Kaur, Harmeet

    2005-03-01

    Traditional centralized approaches to security are difficult to apply to multi-agent systems which are used nowadays in e-commerce applications. Developing a notion of trust that is based on the reputation of an agent can provide a softer notion of security that is sufficient for many multi-agent applications. Our paper proposes a mechanism for computing reputation of the trustee agent for use by the trustier agent. The trustier agent computes the reputation based on its own experience as well as the experience the peer agents have with the trustee agents. The trustier agents intentionally interact with the peer agents to get their experience information in the form of recommendations. We have also considered the case of unintentional encounters between the referee agents and the trustee agent, which can be directly between them or indirectly through a set of interacting agents. The clustering is done to filter off the noise in the recommendations in the form of outliers. The trustier agent clusters the recommendations received from referee agents on the basis of the distances between recommendations using the hierarchical agglomerative method. The dendogram hence obtained is cut at the required similarity level which restricts the maximum distance between any two recommendations within a cluster. The cluster with maximum number of elements denotes the views of the majority of recommenders. The center of this cluster represents the reputation of the trustee agent which can be computed using c-means algorithm.

  18. From My Agent to Our Agent: Exploring Collective Adaptive Agent via Barnga

    NASA Astrophysics Data System (ADS)

    Ushida, Yuya; Hattori, Kiyohiko; Takadama, Keiki

    This paper explores the collective adaptive agent that adapts to agroup in contrast with the individual adaptive agent that adapts to a single user. For this purpose, this paper starts by defining the collective adaptive situation through an analysis of the subject experiments in the playing card game, Barnga, and investigates the factors that lead the group to the collective adaptive situation. Intensive simulations using Barnga agents have revealed the following implications: (1) the leader who takes account of other players' opinions contributes to guide players to the collective adaptation situation, and (2) an appropriate role balance among players (i.e., the leader, the claiming and quiet player, which make the most and least number of corrections) is required to derive the collective adaptive situation.

  19. Other Viruses and Viruslike Agents

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The diseases reported under 'Virus and Virus-like Agents' in the first volume of this compendium, with the exception of Cherry rasp leaf virus and Rubus chinese seed-borne virus, should be considered oddities since there are no known type isolates available for these reported viruses. Without a po...

  20. SEM: A Cultural Change Agent

    ERIC Educational Resources Information Center

    Barnes, Bradley; Bourke, Brian

    2015-01-01

    The authors advance the concept that institutional culture is a purposeful framework by which to view SEM's utility, particularly as a cultural change agent. Through the connection of seemingly independent functions of performance and behavior, implications emerge that deepen the understanding of the influence of culture on performance outcomes…

  1. Triggered pore-forming agents

    DOEpatents

    Bayley, H.; Walker, B.J.; Chang, C.Y.; Niblack, B.; Panchal, R.

    1998-07-07

    An inactive pore-forming agent is revealed which is activated to lytic function by a condition such as pH, light, heat, reducing potential, or metal ion concentration, or substance such as a protease, at the surface of a cell. 30 figs.

  2. Nucleotide cleaving agents and method

    DOEpatents

    Que, Jr., Lawrence (Roseville, MN); Hanson, Richard S. (Falcon Heights, MN); Schnaith, Leah M. T. (Redwing, MN)

    2000-01-01

    The present invention provides a unique series of nucleotide cleaving agents and a method for cleaving a nucleotide sequence, whether single-stranded or double-stranded DNA or RNA, using and a cationic metal complex having at least one polydentate ligand to cleave the nucleotide sequence phosphate backbone to yield a hydroxyl end and a phosphate end.

  3. An Autonomous Spacecraft Agent Prototype

    NASA Technical Reports Server (NTRS)

    Pell, Barney; Bernard, Douglas E.; Chien, Steve A.; Gat, Erann; Muscettola, Nicola; Nayak, P. Pandurang; Wagner, Michael D.; Williams, Brian C.

    1997-01-01

    This paper describes the New Millennium Remote Agent (NMRA) architecture for autonomous spacecraft control systems. This architecture integrates traditional real-time monitoring and control with constraint-based planning and scheduling, robust multi-threaded execution, and model-based diagnosis and reconfiguration.

  4. SEM: A Cultural Change Agent

    ERIC Educational Resources Information Center

    Barnes, Bradley; Bourke, Brian

    2015-01-01

    The authors advance the concept that institutional culture is a purposeful framework by which to view SEM's utility, particularly as a cultural change agent. Through the connection of seemingly independent functions of performance and behavior, implications emerge that deepen the understanding of the influence of culture on performance outcomes…

  5. Foodborne illness and microbial agents

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Foodborne illnesses result from the consumption of food containing microbial agents such as bacteria, viruses, parasites or food contaminated by poisonous chemicals or bio-toxins. Pathogen proliferation is due to nutrient composition of foods, which are capable of supporting the growth of microorgan...

  6. Direct Vasodilators and Sympatholytic Agents.

    PubMed

    McComb, Meghan N; Chao, James Y; Ng, Tien M H

    2016-01-01

    Direct vasodilators and sympatholytic agents were some of the first antihypertensive medications discovered and utilized in the past century. However, side effect profiles and the advent of newer antihypertensive drug classes have reduced the use of these agents in recent decades. Outcome data and large randomized trials supporting the efficacy of these medications are limited; however, in general the blood pressure-lowering effect of these agents has repeatedly been shown to be comparable to other more contemporary drug classes. Nevertheless, a landmark hypertension trial found a negative outcome with a doxazosin-based regimen compared to a chlorthalidone-based regimen, leading to the removal of α-1 adrenergic receptor blockers as first-line monotherapy from the hypertension guidelines. In contemporary practice, direct vasodilators and sympatholytic agents, particularly hydralazine and clonidine, are often utilized in refractory hypertension. Hydralazine and minoxidil may also be useful alternatives for patients with renal dysfunction, and both hydralazine and methyldopa are considered first line for the treatment of hypertension in pregnancy. Hydralazine has also found widespread use for the treatment of systolic heart failure in combination with isosorbide dinitrate (ISDN). The data to support use of this combination in African Americans with heart failure are particularly robust. Hydralazine with ISDN may also serve as an alternative for patients with an intolerance to angiotensin antagonists. Given these niche indications, vasodilators and sympatholytics are still useful in clinical practice; therefore, it is prudent to understand the existing data regarding efficacy and the safe use of these medications. PMID:26033778

  7. Symposium on antimicrobial agents. Metronidazole.

    PubMed

    Rosenblatt, J E; Edson, R S

    1987-11-01

    Metronidazole, a nitroimidazole derivative, is a unique antimicrobial agent that is active against both bacterial and parasitic organisms, although only the anaerobic members of these groups are susceptible. It has been used for the treatment of trichomoniasis for almost 30 years and is also effective in amebiasis and giardiasis. More recently, metronidazole has emerged as a principal agent for the treatment of anaerobic infections. It is highly effective against all species of anaerobes except certain non-spore-forming gram-positive bacilli and cocci and is the only agent rapidly bactericidal against the Bacteroides fragilis group. The hydroxy metabolite is 65% as effective as metronidazole and may play a major therapeutic role. Clinical studies have substantiated its efficacy for prophylaxis during elective colorectal surgical procedures and the treatment of deep abdominal sepsis (usually in combination with another agent such as an aminoglycoside). Metronidazole is the treatment of choice for bacterial vaginosis and seems to be as effective as vancomycin for treatment of Clostridium difficile-related diarrhea and colitis. Good blood levels are produced after both oral and intravenous administration, and side effects are infrequent and minimal. Metronidazole should not be taken during the first trimester of pregnancy because of concerns about mutagenicity. Tinidazole and ornidazole are recently developed nitroimidazole derivatives that have even greater antimicrobial activity than metronidazole. PMID:3312851

  8. Depression: The Differing Narratives of Couples in Couple Therapy

    ERIC Educational Resources Information Center

    Rautiainen, Eija-Liisa; Aaltonen, Jukka

    2010-01-01

    How does the spouse of a person with depression take part in constructing narratives of depression in couple therapy? In this study we examined couples' ways of co-constructing narratives of depression in couple therapy. Three couple therapy processes were chosen for the study, one spouse in each couple having been referred to an outpatient clinic…

  9. Contactless Rotary Electrical Couplings

    NASA Technical Reports Server (NTRS)

    Kumagai, Hiroyuki

    2003-01-01

    Rotary electrical couplings based on induction (transformer action) rather than conduction between rotating and stationary circuitry have been invented. These couplings provide an alternative to slip rings and contact brushes. Mechanical imperfections of slip-ring and brush contact surfaces and/or dust particles trapped between these surfaces tend to cause momentary interruptions in electrical contact and thereby give rise to electrical noise. This source of noise can be eliminated in the inductive rotary couplings because no direct contact is necessary for transformer action.

  10. Spatial process and data models : toward integration of agent-based models and GIS.

    SciTech Connect

    Brown, D. G.; North, M. J.; Robinson, D. T.; Riolo, R.; Rand, W.; Decision and Information Sciences; Univ. of Michigan

    2007-10-01

    The use of object-orientation for both spatial data and spatial process models facilitates their integration, which can allow exploration and explanation of spatial-temporal phenomena. In order to better understand how tight coupling might proceed and to evaluate the possible functional and efficiency gains from such a tight coupling, we identify four key relationships affecting how geographic data (fields and objects) and agent-based process models can interact: identity, causal, temporal and topological. We discuss approaches to implementing tight integration, focusing on a middleware approach that links existing GIS and ABM development platforms, and illustrate the need and approaches with example agent-based models.

  11. Biologic agents in juvenile spondyloarthropathies.

    PubMed

    Katsicas, María Martha; Russo, Ricardo

    2016-01-01

    The juvenile spondyloarthropathies (JSpA) are a group of related rheumatic diseases characterized by involvement of peripheral large joints, axial joints, and entheses (enthesitis) that begin in the early years of life (prior to 16(th) birthday).The nomenclature and concept of spondyloarthropathies has changed during the last few decades. Although there is not any specific classification of JSpA, diseases under the spondyloarthropathy nomenclature umbrella in the younger patients include: the seronegative enthesitis and arthropathy (SEA) syndrome, juvenile ankylosing spondylitis, reactive arthritis, and inflammatory bowel disease-associated arthritis. Moreover, the ILAR criteria for Juvenile Idiopathic Arthritis includes two categories closely related to spondyloarthritis: Enthesitis-related arthritis and psoriatic arthritis.We review the pathophysiology and the use of biological agents in JSpA. JSpA are idiopathic inflammatory diseases driven by an altered balance in the proinflammatory cytokines. There is ample evidence on the role of tumor necrosis factor (TNF) and interleukin-17 in the physiopathology of these entities. Several non-biologic and biologic agents have been used with conflicting results in the treatment of these complex diseases. The efficacy and safety of anti-TNF agents, such as etanercept, infliximab and adalimumab, have been analysed in controlled and uncontrolled trials, usually showing satisfactory outcomes. Other biologic agents, such as abatacept, tocilizumab and rituximab, have been insufficiently studied and their role in the therapy of SpA is uncertain. Interleukin-17-blocking agents are promising alternatives for the treatment of JSpA patients in the near future. Recommendations for the treatment of patients with JSpA have recently been proposed and are discussed in the present review. PMID:26968522

  12. Limonene and tetrahydrofurfuryl alcohol cleaning agent

    DOEpatents

    Bohnert, G.W.; Carter, R.D.; Hand, T.E.; Powers, M.T.

    1997-10-21

    The present invention is a tetrahydrofurfuryl alcohol and limonene cleaning agent and method for formulating and/or using the cleaning agent. This cleaning agent effectively removes both polar and nonpolar contaminants from various electrical and mechanical parts and is readily used without surfactants, thereby reducing the need for additional cleaning operations. The cleaning agent is warm water rinsable without the use of surfactants. The cleaning agent can be azeotropic, enhancing ease of use in cleaning operations and ease of recycling.

  13. Limonene and tetrahydrofurfuryl alcohol cleaning agent

    DOEpatents

    Bohnert, George W.; Carter, Richard D.; Hand, Thomas E.; Powers, Michael T.

    1996-05-07

    The present invention is a tetrahydrofurfuryl alcohol and limonene or terpineol cleaning agent and method for formulating and/or using the cleaning agent. This cleaning agent effectively removes both polar and nonpolar contaminants from various electrical and mechanical parts and is readily used without surfactants, thereby reducing the need for additional cleaning operations. The cleaning agent is warm water rinsable without the use of surfactants. The cleaning agent can be azeotropic, enhancing ease of use in cleaning operations and ease of recycling.

  14. Limonene and tetrahydrofurfurly alcohol cleaning agent

    DOEpatents

    Bohnert, George W.; Carter, Richard D.; Hand, Thomas E.; Powers, Michael T.

    1997-10-21

    The present invention is a tetrahydrofurfuryl alcohol and limonene cleaning agent and method for formulating and/or using the cleaning agent. This cleaning agent effectively removes both polar and nonpolar contaminants from various electrical and mechanical parts and is readily used without surfactants, thereby reducing the need for additional cleaning operations. The cleaning agent is warm water rinsable without the use of surfactants. The cleaning agent can be azeotropic, enhancing ease of use in cleaning operations and ease of recycling.

  15. High temperature profile modification agents and methods for using same

    SciTech Connect

    Ryles, R.G.; Robustelli, A.G.; Clechiello, J.V.

    1989-05-02

    This patent describes a method for altering the permeability of at least a portion of a subterranean formation penetrated by at least one wellbore comprising the steps of passing a fluid gelable composition into the formation to a preselected location and gelling the composition to modify the liquid flow profile of the portion of the formation. The improvement consists of using, as the fluid gellable composition, a composition comprising: (a) water; (b) a water-thickening and cross-linkable amount of a water-dispersible polymer consisting essentially of: from about 30 to about 99 mol % of 2-acrylamido-2-methylpropanesulfonic acid units or salts thereof and from about 70 to 1 mol % of acrylic acid units or salts thereof and (c) an amount of a polyvalent metal capable of cross-linking the polymer to form a stable gel, wherein the polyvalent metal in component (c) is provided in the form of a redox couple, the redox couple comprising (iii) at least one oxidizing agent comprising a water-soluble compound of the polyvalent metal in its highest valence state and being capable of being reduced to a lower valence state and being selected from the group consisting of hexavalent chromium compounds and permanganates and (iv) a reducing agent effective to reduce the higher valence metal in oxidizing agent (iii) to a lower polyvalent valence state.

  16. Coupling in the Tevatron

    SciTech Connect

    Gelfand, N.M.

    1994-12-01

    The performance of the Fermilab Tevatron Collider at the commencement of run Ib was far below expectations. After a frustrating period of several months, a low-{beta} quad downstream of the interaction point at B0 was found to be rolled. This rolled quadrupole coupled the horizontal and vertical motion of the Tevatron beams. It also made matching the beam from the Main Ring to the Tevatron impossible, resulting in emittance blow up on injection. The net result of the roll was a significant reduction in the Tevatron luminosity. When the roll in the quadrupole was corrected the performance of the Tevatron improved dramatically. This note will discuss the experimental data indicating the presence of coupling and subsequent calculations which show how coupling an affect the luminosity. It is not intended to exhaust a discussion of coupling, which hopefully will be understood well enough to be discussed in a subsequent note.

  17. Disformally coupled inflation

    NASA Astrophysics Data System (ADS)

    van de Bruck, Carsten; Koivisto, Tomi; Longden, Chris

    2016-03-01

    A disformal coupling between two scalar fields is considered in the context of cosmological inflation. The coupling introduces novel derivative interactions mixing the kinetic terms of the fields but without introducing superluminal or unstable propagation of the two scalar fluctuation modes. Though the typical effect of the disformal coupling is to inhibit one of the fields from inflating the universe, the energy density of the other field can drive viable near Sitter -inflation in the presence of nontrivial disformal dynamics, in particular when one assumes exponential instead of power-law form for the couplings. The linear perturbation equations are written for the two-field system, its canonical degrees of freedom are quantised, their spectra are derived and the inflationary predictions are reported for numerically solved exponential models. A generic prediction is low tensor-to-scalar ratio.

  18. Theory of agent-based market models with controlled levels of greed and anxiety

    NASA Astrophysics Data System (ADS)

    Papadopoulos, P.; Coolen, A. C. C.

    2010-01-01

    We use generating functional analysis to study minority-game-type market models with generalized strategy valuation updates that control the psychology of agents' actions. The agents' choice between trend-following and contrarian trading, and their vigor in each, depends on the overall state of the market. Even in 'fake history' models, the theory now involves an effective overall bid process (coupled to the effective agent process) which can exhibit profound remanence effects and new phase transitions. For some models the bid process can be solved directly, others require Maxwell-construction-type approximations.

  19. Integrated Information Framework for Intelligent Cooperative Design Based on Multi-Agent System and XML

    NASA Astrophysics Data System (ADS)

    Yan, Cao; Lina, Yang; Yanli, Yang; Hua, Chen

    2008-11-01

    To meet the requirements of distributed cooperation in various industries, the architecture of cooperative design based on multi-agent system on Internet is proposed by analyzing cooperative design pattern, and its key technologies, such as product developing process management, information management, and conflict resolution, are discussed. An integrated information framework of loosely coupling modules is proposed which supports concurrent work mode based on multi-agent system. Integrating Web service technique and agent technique into this framework can organize many cooperative members and their activities effectively though they are distributed at different places. Finally, system development mode based on Web is put forward.

  20. The New Agent: A Qualitative Study to Strategically Adapt New Agent Professional Development

    ERIC Educational Resources Information Center

    Baker, Lauri M.; Hadley, Gregg

    2014-01-01

    The qualitative study reported here assessed the needs of agents related to new agent professional development to improve the current model. Agents who participated in new agent professional development within the last 5 years were selected to participate in focus groups to determine concerns and continued needs. Agents enjoyed networking and…

  1. The New Agent: A Qualitative Study to Strategically Adapt New Agent Professional Development

    ERIC Educational Resources Information Center

    Baker, Lauri M.; Hadley, Gregg

    2014-01-01

    The qualitative study reported here assessed the needs of agents related to new agent professional development to improve the current model. Agents who participated in new agent professional development within the last 5 years were selected to participate in focus groups to determine concerns and continued needs. Agents enjoyed networking and…

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

    NASA Technical Reports Server (NTRS)

    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 intraoperative neuroprotection.

  3. Partner switching promotes cooperation among myopic agents on a geographical plane.

    PubMed

    Li, Yixiao; Min, Yong; Zhu, Xiaodong; Cao, Jie

    2013-02-01

    We study the coupling dynamics between the evolution of cooperation and the evolution of partnership network on a geographical plane. While agents play networked prisoner's dilemma games, they can dynamically adjust their partnerships based on local information about reputation. We incorporate geographical features into the process of the agent's partner switching and investigate the corresponding effects. At each time step of the coevolution, a random agent can either update his strategy by imitation or adjust his partnership by switching from the lowest reputation partner to the highest reputation one among his neighbors. We differentiate two types of neighbors: geographical neighbors (i.e., the set of agents who are close to the focal agent in terms of geographical distance) and connectivity neighbors (i.e., the set of agents who are close to the focal agent in the partnership network in terms of geodesic distance). We find that switching to either geographical neighbors or connectivity neighbors enhances cooperation greatly in a wide parameter range. Cooperation can be favored in a much stricter condition when agents switch to connectivity neighbors more frequently. However, an increasing tendency of reconnecting to geographical neighbors shortens the geographical distance between a pair of partners on average. When agents consider the cost of geographical distance in adjusting the partnership, they are prone to reconnect to geographical neighbors. PMID:23496584

  4. CATS-based Agents That Err

    NASA Technical Reports Server (NTRS)

    Callantine, Todd J.

    2002-01-01

    This report describes preliminary research on intelligent agents that make errors. Such agents are crucial to the development of novel agent-based techniques for assessing system safety. The agents extend an agent architecture derived from the Crew Activity Tracking System that has been used as the basis for air traffic controller agents. The report first reviews several error taxonomies. Next, it presents an overview of the air traffic controller agents, then details several mechanisms for causing the agents to err in realistic ways. The report presents a performance assessment of the error-generating agents, and identifies directions for further research. The research was supported by the System-Wide Accident Prevention element of the FAA/NASA Aviation Safety Program.

  5. Software for Automation of Real-Time Agents, Version 2

    NASA Technical Reports Server (NTRS)

    Fisher, Forest; Estlin, Tara; Gaines, Daniel; Schaffer, Steve; Chouinard, Caroline; Engelhardt, Barbara; Wilklow, Colette; Mutz, Darren; Knight, Russell; Rabideau, Gregg; Chien, Steve; Simmons, Reid; Apfelbaum, David

    2005-01-01

    Version 2 of Closed Loop Execution and Recovery (CLEaR) has been developed. CLEaR is an artificial intelligence computer program for use in planning and execution of actions of autonomous agents, including, for example, Deep Space Network (DSN) antenna ground stations, robotic exploratory ground vehicles (rovers), robotic aircraft (UAVs), and robotic spacecraft. CLEaR automates the generation and execution of command sequences, monitoring the sequence execution, and modifying the command sequence in response to execution deviations and failures as well as new goals for the agent to achieve. The development of CLEaR has focused on the unification of planning and execution to increase the ability of the autonomous agent to perform under tight resource and time constraints coupled with uncertainty in how much of resources and time will be required to perform a task. This unification is realized by extending the traditional three-tier robotic control architecture by increasing the interaction between the software components that perform deliberation and reactive functions. The increase in interaction reduces the need to replan, enables earlier detection of the need to replan, and enables replanning to occur before an agent enters a state of failure.

  6. Bacteriocins as Potential Anticancer Agents

    PubMed Central

    Kaur, Sumanpreet; Kaur, Sukhraj

    2015-01-01

    Cancer remains one of the leading causes of deaths worldwide, despite advances in its treatment and detection. The conventional chemotherapeutic agents used for the treatment of cancer have non-specific toxicity toward normal body cells that cause various side effects. Secondly, cancer cells are known to develop chemotherapy resistance in due course of treatment. Thus, the demand for novel anti-cancer agents is increasing day by day. Some of the experimental studies have reported the therapeutic potential of bacteriocins against various types of cancer cell lines. Bacteriocins are ribosomally-synthesized cationic peptides secreted by almost all groups of bacteria. Some bacteriocins have shown selective cytotoxicity toward cancer cells as compared to normal cells. This makes them promising candidates for further investigation and clinical trials. In this review article, we present the overview of the various cancer cell-specific cytotoxic bacteriocins, their mode of action and efficacies. PMID:26617524

  7. Oral agents in multiple sclerosis.

    PubMed

    Lorefice, L; Fenu, G; Frau, J; Coghe, G C; Marrosu, M G; Cocco, E

    2015-01-01

    Multiple sclerosis (MS) is a complex autoimmune disease of the central nervous system. Disease-modifying drugs licensed for MS treatment have been developed to reduce relapse rates and halt disease progression. The majority of current MS drugs involve regular, parenteral administration, affecting long-term adherence and thus reducing treatment efficacy. Over the last two decades great progress has been made towards developing new MS therapies with different modes of action and biologic effects. In particular, oral drugs have generated much interest because of their convenience and positive impact on medication adherence. Fingolimod was the first launched oral treatment for relapsing-remitting MS; recently, Teriflunomide and Dimethyl fumarate have also been approved as oral disease-modifying agents. In this review, we summarize and discuss the history, pharmacodynamics, efficacy, and safety of oral agents that have been approved or are under development for the selective treatment of MS. PMID:25924620

  8. Bacteriocins as Potential Anticancer Agents.

    PubMed

    Kaur, Sumanpreet; Kaur, Sukhraj

    2015-01-01

    Cancer remains one of the leading causes of deaths worldwide, despite advances in its treatment and detection. The conventional chemotherapeutic agents used for the treatment of cancer have non-specific toxicity toward normal body cells that cause various side effects. Secondly, cancer cells are known to develop chemotherapy resistance in due course of treatment. Thus, the demand for novel anti-cancer agents is increasing day by day. Some of the experimental studies have reported the therapeutic potential of bacteriocins against various types of cancer cell lines. Bacteriocins are ribosomally-synthesized cationic peptides secreted by almost all groups of bacteria. Some bacteriocins have shown selective cytotoxicity toward cancer cells as compared to normal cells. This makes them promising candidates for further investigation and clinical trials. In this review article, we present the overview of the various cancer cell-specific cytotoxic bacteriocins, their mode of action and efficacies. PMID:26617524

  9. Novel Antiangiogenic Agents in Dermatology

    PubMed Central

    Berrios, Ricardo L.; Arbiser, Jack L.

    2011-01-01

    Because angiogenesis underlies the pathogenesis of numerous conditions (cancer, psoriasis, macular degeneration), there is a pressing need for continued investigations into angiogenic signaling and potential drug targets. Antiangiogenic agents can be classified as either direct or indirect. Direct antiangiogenics act on untransformed endothelial cells to prevent differentiation and proliferation; indirect antiangiogenics act to inhibit factors involved in proangiogenic signaling. Agents currently available with dermatologic indications are few, while several established and novel biologics targeting various proangiogenic factors are currently being investigated for potential dermatologic uses, but the jury is still out on their efficacy and safety. In this review, we highlight our experience with a group of existing and novel, small molecules that combine several modes of action against angiogenesis in addition to other properties – triarylmethane dyes and fulvene derivatives. PMID:21172300

  10. [Alternative agents used in ADHD].

    PubMed

    Hässler, Frank; Dück, Alexander; Reis, Olaf; Buchmann, Johannes

    2009-01-01

    Attention-deficit/hyperactivity disorder (ADHD) is, with a prevalence of 2% to 6%, one of the most common neurobehavioral disorder affecting children and adolescents, persisting into adulthood. Comorbidity and psychosocial circumstances enter into the choice of intervention strategies. Several agents have been demonstrated effective in treating individuals with ADHD. Direct or indirect attenuation of dopamine and norepinephrine neurotransmission appears closely related to both the stimulant and nonstimulant medications efficacious in ADHD. However, important differences concerning efficacy and side effects exist both between and with the specific classes of agents like neuroleptics, antidepressants, antiepileptics, alpha-agonists, beta-blockers, buspiron, l-dopa, melatonin, pycnogenol, zinc, magnesium, polyunsaturated fatty acids, and homeopathy. Elucidating the various mechanisms of action of ADHD medications may lead to better choices in matching potential responses to the characteristics of individuals. We review the purported mechanism of action and available evidence for selected complementary and alternative medicine therapies for ADHD in childhood and adolescence. PMID:19105161

  11. [Colitis due to chemotherapeutic agent].

    PubMed

    Yang, X Y

    1990-09-01

    From 1965 through 1989, a total of 1,382 cases of malignant trophoblastic neoplasms, were treated in our hospital. Colitis related to chemotherapy was observed in 110 cases. This toxic reaction was specific to 5-Fluorouracil treatment and may result in pseudomembranous colitis if improperly treated. Staphylococcus aureus or Clostridium difficile was the causative agent. For the early detection of this disease, it is necessary to monitor the bacteria flora in the smear of fecal substance. Vancomycin and Metronidazole together with lactobacillus preparation were given and proved to be effective in most cases. The mechanism of formation of pseudomembranous colitis, the causative agents and method of diagnosis and treatment were discussed. PMID:2178081

  12. ?-adrenoceptor blocking agents and lipolysis

    PubMed Central

    Harms, H. H.; De Vente, J.; Zaagsma, J.

    1982-01-01

    1 The pharmacological characteristics of ?-adrenoceptor subtypes on adipocytes of various mammalian species, including man, are reviewed. 2 Rat adipocytes possess a homogeneous population of ?-adrenoceptors with properties that clearly distinguish them from `classic' ?1- and ?2-adrenoceptors, although they share certain features with both. Thus, rat adipocyte ?-adrenoceptors should be considered as non-?1-non-?2 receptors, like the atypical ?-adrenoceptors found on erythrocytes of turkey, chicken and frog. 3 Preliminary data suggest that adipocyte ?-adrenoceptors of guinea pig and swine are different from `classic' ?1- and ?2-adrenoceptors as well, whereas in the dog and possibly in the cat, a mixture of ?1- and ?2-receptors mediates catecholamine induced lipolysis. 4 Human adipocyte ?-adrenoceptors probably also consist of at least two subtypes. Insufficient data are available to decide if these ?-adrenoceptors are identical with `classic' ?1- and ?2-receptors, or share some hybrid characteristics with rat adipocyte ?-adrenoceptors. 5 In vivo studies in animals as well as in man, tend to corroborate in vitro results. Cardioselective ?-adrenoceptor blocking agents, like atenolol, metoprolol and practolol are not as effective in blocking catecholamine induced lipolysis as non-cardioselective agents like propranolol and pindolol. The relatively low potency of cardioselective ?-adrenoceptor blocking agents is found using either isoprenaline, adrenaline or exercise as the agonist, suggesting that ?2-adrenoceptors are involved. On the other hand, cardioselective agents, though less effective than non-cardioselective compounds, have a significant inhibitory effect on catecholamine induced lipolysis at doses that have only minimal effect on other ?2-adrenoceptor mediated responses, which argues for participation of ?1-adrenoceptors. 6 Thus, human in vitro and in vivo data are consistent with, but not proof of the hypothesis that a mixture of ?1- and ?2-adrenoceptors mediates lipolysis induced by sympathetic activation. 7 Species differences in ?-adrenoceptor subtype characteristics may complicate the interpretation of the relevance of animal data for the understanding of ?-adrenoceptor mediated effects in human adipocytes. PMID:6125168

  13. Swarm autonomic agents with self-destruct capability

    NASA Technical Reports Server (NTRS)

    Hinchey, Michael G. (Inventor); Sterritt, Roy (Inventor)

    2011-01-01

    Systems, methods and apparatus are provided through which in some embodiments an autonomic entity manages a system by generating one or more stay alive signals based on the functioning status and operating state of the system. In some embodiments, an evolvable synthetic neural system is operably coupled to one or more evolvable synthetic neural systems in a hierarchy. The evolvable neural interface receives and generates heartbeat monitor signals and pulse monitor signals that are used to generate a stay alive signal that is used to manage the operations of the synthetic neural system. In another embodiment an asynchronous Alice signal (Autonomic license) requiring valid credentials of an anonymous autonomous agent is initiated. An unsatisfactory Alice exchange may lead to self-destruction of the anonymous autonomous agent for self-protection.

  14. Swarm autonomic agents with self-destruct capability

    NASA Technical Reports Server (NTRS)

    Hinchey, Michael G. (Inventor); Sterritt, Roy (Inventor)

    2009-01-01

    Systems, methods and apparatus are provided through which in some embodiments an autonomic entity manages a system by generating one or more stay alive signals based on the functioning status and operating state of the system. In some embodiments, an evolvable synthetic neural system is operably coupled to one or more evolvable synthetic neural systems in a hierarchy. The evolvable neural interface receives and generates heartbeat monitor signals and pulse monitor signals that are used to generate a stay alive signal that is used to manage the operations of the synthetic neural system. In another embodiment an asynchronous Alice signal (Autonomic license) requiring valid credentials of an anonymous autonomous agent is initiated. An unsatisfactory Alice exchange may lead to self-destruction of the anonymous autonomous agent for self-protection.

  15. From actors to agents in socio-ecological systems models

    PubMed Central

    Rounsevell, M. D. A.; Robinson, D. T.; Murray-Rust, D.

    2012-01-01

    The ecosystem service concept has emphasized the role of people within socio-ecological systems (SESs). In this paper, we review and discuss alternative ways of representing people, their behaviour and decision-making processes in SES models using an agent-based modelling (ABM) approach. We also explore how ABM can be empirically grounded using information from social survey. The capacity for ABM to be generalized beyond case studies represents a crucial next step in modelling SESs, although this comes with considerable intellectual challenges. We propose the notion of human functional types, as an analogy of plant functional types, to support the expansion (scaling) of ABM to larger areas. The expansion of scope also implies the need to represent institutional agents in SES models in order to account for alternative governance structures and policy feedbacks. Further development in the coupling of human-environment systems would contribute considerably to better application and use of the ecosystem service concept. PMID:22144388

  16. New therapeutic agents for acromegaly.

    PubMed

    Melmed, Shlomo

    2016-02-01

    The currently available somatostatin receptor ligands (SRLs) and growth hormone (GH) antagonists are used to control levels of GH and insulin-like growth factor 1 (IGF-1) in patients with acromegaly. However, these therapies are limited by wide variations in efficacy, associated adverse effects and the need for frequent injections. A phase III trial of oral octreotide capsules demonstrated that this treatment can safely sustain suppressed levels of GH and IGF-1 and reduce the severity of symptoms in patients with acromegaly previously controlled by injectable SRL therapy, with the added benefit of no injection-site reactions. Phase I and phase II trials of the pan-selective SRL DG3173, the liquid crystal octreotide depot CAM2029 and an antisense oligonucleotide directed against the GH receptor have shown that these agents can be used to achieve biochemical suppression in acromegaly and have favourable safety profiles. This Review outlines the need for new therapeutic agents for patients with acromegaly, reviews clinical trial data of investigational agents and considers how these therapies might best be integrated into clinical practice. PMID:26610414

  17. Chemotherapy and Dietary Phytochemical Agents

    PubMed Central

    Sak, Katrin

    2012-01-01

    Chemotherapy has been used for cancer treatment already for almost 70 years by targeting the proliferation potential and metastasising ability of tumour cells. Despite the progress made in the development of potent chemotherapy drugs, their toxicity to normal tissues and adverse side effects in multiple organ systems as well as drug resistance have remained the major obstacles for the successful clinical use. Cytotoxic agents decrease considerably the quality of life of cancer patients manifesting as acute complaints and impacting the life of survivors also for years after the treatment. Toxicity often limits the usefulness of anticancer agents being also the reason why many patients discontinue the treatment. The nutritional approach may be the means of helping to raise cancer therapy to a new level of success as supplementing or supporting the body with natural phytochemicals cannot only reduce adverse side effects but improve also the effectiveness of chemotherapeutics. Various plant-derived compounds improve the efficiency of cytotoxic agents, decrease their resistance, lower and alleviate toxic side effects, reduce the risk of tumour lysis syndrome, and detoxify the body of chemotherapeutics. The personalised approach using various phytochemicals provides thus a new dimension to the standard cancer therapy for improving its outcome in a complex and complementary way. PMID:23320169

  18. Pharmacologic Agents for Chronic Diarrhea.

    PubMed

    Lee, Kwang Jae

    2015-10-01

    Chronic diarrhea is usually associated with a number of non-infectious causes. When definitive treatment is unavailable, symptomatic drug therapy is indicated. Pharmacologic agents for chronic diarrhea include loperamide, 5-hydroxytryptamine type 3 (5-HT3) receptor antagonists, diosmectite, cholestyramine, probiotics, antispasmodics, rifaximin, and anti-inflammatory agents. Loperamide, a synthetic opiate agonist, decreases peristaltic activity and inhibits secretion, resulting in the reduction of fluid and electrolyte loss and an increase in stool consistency. Cholestyramine is a bile acid sequestrant that is generally considered as the first-line treatment for bile acid diarrhea. 5-HT3 receptor antagonists have significant benefits in patients with irritable bowel syndrome (IBS) with diarrhea. Ramosetron improves stool consistency as well as global IBS symptoms. Probiotics may have a role in the prevention of antibiotic-associated diarrhea. However, data on the role of probiotics in the treatment of chronic diarrhea are lacking. Diosmectite, an absorbent, can be used for the treatment of chronic functional diarrhea, radiation-induced diarrhea, and chemotherapy-induced diarrhea. Antispasmodics including alverine citrate, mebeverine, otilonium bromide, and pinaverium bromide are used for relieving diarrheal symptoms and abdominal pain. Rifaximin can be effective for chronic diarrhea associated with IBS and small intestinal bacterial overgrowth. Budesonide is effective in both lymphocytic colitis and collagenous colitis. The efficacy of mesalazine in microscopic colitis is weak or remains uncertain. Considering their mechanisms of action, these agents should be prescribed properly. PMID:26576135

  19. Pharmacologic Agents for Chronic Diarrhea

    PubMed Central

    2015-01-01

    Chronic diarrhea is usually associated with a number of non-infectious causes. When definitive treatment is unavailable, symptomatic drug therapy is indicated. Pharmacologic agents for chronic diarrhea include loperamide, 5-hydroxytryptamine type 3 (5-HT3) receptor antagonists, diosmectite, cholestyramine, probiotics, antispasmodics, rifaximin, and anti-inflammatory agents. Loperamide, a synthetic opiate agonist, decreases peristaltic activity and inhibits secretion, resulting in the reduction of fluid and electrolyte loss and an increase in stool consistency. Cholestyramine is a bile acid sequestrant that is generally considered as the first-line treatment for bile acid diarrhea. 5-HT3 receptor antagonists have significant benefits in patients with irritable bowel syndrome (IBS) with diarrhea. Ramosetron improves stool consistency as well as global IBS symptoms. Probiotics may have a role in the prevention of antibiotic-associated diarrhea. However, data on the role of probiotics in the treatment of chronic diarrhea are lacking. Diosmectite, an absorbent, can be used for the treatment of chronic functional diarrhea, radiation-induced diarrhea, and chemotherapy-induced diarrhea. Antispasmodics including alverine citrate, mebeverine, otilonium bromide, and pinaverium bromide are used for relieving diarrheal symptoms and abdominal pain. Rifaximin can be effective for chronic diarrhea associated with IBS and small intestinal bacterial overgrowth. Budesonide is effective in both lymphocytic colitis and collagenous colitis. The efficacy of mesalazine in microscopic colitis is weak or remains uncertain. Considering their mechanisms of action, these agents should be prescribed properly. PMID:26576135

  20. Optimization of (2,3-dihydro-1-benzofuran-3-yl)acetic acids: discovery of a non-free fatty acid-like, highly bioavailable G protein-coupled receptor 40/free fatty acid receptor 1 agonist as a glucose-dependent insulinotropic agent.

    PubMed

    Negoro, Nobuyuki; Sasaki, Shinobu; Mikami, Satoshi; Ito, Masahiro; Tsujihata, Yoshiyuki; Ito, Ryo; Suzuki, Masami; Takeuchi, Koji; Suzuki, Nobuhiro; Miyazaki, Junichi; Santou, Takashi; Odani, Tomoyuki; Kanzaki, Naoyuki; Funami, Miyuki; Morohashi, Akio; Nonaka, Masami; Matsunaga, Shinichiro; Yasuma, Tsuneo; Momose, Yu

    2012-04-26

    G protein-coupled receptor 40 (GPR40)/free fatty acid receptor 1 (FFA1) is a free fatty acid (FFA) receptor that mediates FFA-amplified glucose-stimulated insulin secretion in pancreatic ?-cells. We previously identified (2,3-dihydro-1-benzofuran-3-yl)acetic acid derivative 2 as a candidate, but it had relatively high lipophilicity. Adding a polar functional group on 2 yielded several compounds with lower lipophilicity and little effect on caspase-3/7 activity at 30 ?M (a marker of toxicity in human HepG2 hepatocytes). Three optimized compounds showed promising pharmacokinetic profiles with good in vivo effects. Of these, compound 16 had the lowest lipophilicity. Metabolic analysis of 16 showed a long-acting PK profile due to high resistance to ?-oxidation. Oral administration of 16 significantly reduced plasma glucose excursion and increased insulin secretion during an OGTT in type 2 diabetic rats. Compound 16 (TAK-875) is being evaluated in human clinical trials for the treatment of type 2 diabetes. PMID:22490067

  1. Nonintrusive Raman analysis of chemical agents

    NASA Astrophysics Data System (ADS)

    Christesen, Steven D.; Carrabba, Michael M.; Bello, Job M.

    2002-02-01

    Portable fiber-optic Raman systems are being used to analyze chemical agents and other toxic chemicals in sealed glass containers. These containers include ampoules and bottles that are contents of chemical agent identification sets (CAIS) developed for use in training military personnel in chemical agent identification, safe handling, and decontamination. Real-time nonintrusive analysis of these sets is required so that the items containing chemical agents can be identified for proper disposal. This paper details the laboratory measurement of Raman spectra of chemical agents, Raman scattering cross sections of chemical agents, and the analysis of CAIS items in the field.

  2. Unusual but potential agents of terrorists.

    PubMed

    Holstege, Christopher P; Bechtel, Laura K; Reilly, Tracey H; Wispelwey, Bram P; Dobmeier, Stephen G

    2007-05-01

    Emergency personnel are tasked with the daunting job of being the first to evaluate and manage victims of a terrorist attack. Numerous potential chemical agents could be used by terrorists. The challenge for first responders and local hospital emergency personnel is to prepare for a terrorist event that might use one or more of these agents. As part of that preparation, emergency physicians should have a basic understanding of potential chemical terrorist agents. It is beyond the scope of this article to review all potential terrorist agents. Rather, four potential agents have been chosen for review: sodium monofluoroacetate, trichothecene mycotoxins, vomiting agents, and saxitoxin. PMID:17482032

  3. Agent planning in AgScala

    NASA Astrophysics Data System (ADS)

    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.

  4. Enhancing the efficacy of hormonal agents with selected targeted agents.

    PubMed

    Johnston, Stephen R D

    2009-06-01

    Several selected targeted agents are being investigated in combination with endocrine therapy for patients with breast cancer in an attempt to overcome or prevent endocrine resistance. The role of type I growth factor receptors epidermal growth factor receptor (EGFR) and HER2 in cross-talk with estrogen receptor (ER) signaling has been confirmed in preclinical studies in which various inhibitors have yielded additive or synergistic effects when combined with endocrine agents. Recently, several results from clinical trials investigating this concept have been reported. In ER-positive/HER-positive advanced breast cancer, the addition of trastuzumab to the aromatase inhibitor anastrozole, or the tyrosine kinase inhibitor (TKI) lapatinib to letrozole, both have significantly improved progression-free survival (PFS). The EGFR TKI gefitinib combined with tamoxifen as first-line therapy for ER-positive metastatic disease improved PFS (but not objective response rate) for patients with no previous endocrine therapy or completion of previous adjuvant therapy. A second study in a similar setting showed significant improvement in PFS for gefitinib plus anastrozole. Although it is encouraging that this approach could delay resistance, only a small proportion of patients benefit. Attempts to identify likely responders have been made in the neoadjuvant setting, with pre- and post-treatment biopsies being used to study biomarker changes. A recent preoperative study of letrozole with or without the mammalian target of rapamycin (mTOR) inhibitor everolimus reported greater tumor shrinkage for the combination, with changes in proliferation being predictive for response together with strong expression of protein S6 kinase, a downstream marker of activated mTOR. Key aspects that need to be addressed in future trials include understanding the mechanisms of action for each novel agent, designing the best trial and endpoints to demonstrate added benefit, and ensuring appropriately stratified populations based on previous endocrine exposure and/or sensitivity. PMID:19561004

  5. Novel therapeutic agents in the treatment of metastatic colorectal cancer.

    PubMed

    Pai, Sachin Gopalkrishna; Fuloria, Jyotsna

    2016-01-15

    Over the past couple of decades considerable progress has been made in the management of metastatic colorectal cancers (mCRC) leading to a significant improvement in five-year survival. Although part of this success has been rightly attributed to aggressive surgical management and advances in other adjunct treatments, our understanding of the pathogenesis of cancer and emergence of newer molecular targets for colon cancer has created a powerful impact. In this review article we will discuss various targeted therapies in the management of mCRC. Newer agents on the horizon soon to be incorporated in clinical practice will be briefly reviewed as well. PMID:26798440

  6. Modeling and Visualizing Flow of Chemical Agents Across Complex Terrain

    NASA Technical Reports Server (NTRS)

    Kao, David; Kramer, Marc; Chaderjian, Neal

    2005-01-01

    Release of chemical agents across complex terrain presents a real threat to homeland security. Modeling and visualization tools are being developed that capture flow fluid terrain interaction as well as point dispersal downstream flow paths. These analytic tools when coupled with UAV atmospheric observations provide predictive capabilities to allow for rapid emergency response as well as developing a comprehensive preemptive counter-threat evacuation plan. The visualization tools involve high-end computing and massive parallel processing combined with texture mapping. We demonstrate our approach across a mountainous portion of North California under two contrasting meteorological conditions. Animations depicting flow over this geographical location provide immediate assistance in decision support and crisis management.

  7. Novel therapeutic agents in the treatment of metastatic colorectal cancer

    PubMed Central

    Pai, Sachin Gopalkrishna; Fuloria, Jyotsna

    2016-01-01

    Over the past couple of decades considerable progress has been made in the management of metastatic colorectal cancers (mCRC) leading to a significant improvement in five-year survival. Although part of this success has been rightly attributed to aggressive surgical management and advances in other adjunct treatments, our understanding of the pathogenesis of cancer and emergence of newer molecular targets for colon cancer has created a powerful impact. In this review article we will discuss various targeted therapies in the management of mCRC. Newer agents on the horizon soon to be incorporated in clinical practice will be briefly reviewed as well. PMID:26798440

  8. Aerosolized biologic toxins as agents of warfare and terrorism.

    PubMed

    Zapor, Michael; Fishbain, Joel T

    2004-03-01

    Incomplete participation in the 1972 Biological Weapons Convention treaty and noncompliance by several signatory nations makes the malicious use of aerosolized biologic toxins a continuing threat. Unfortunately,prompt diagnosis of toxin exposure may be confounded by a paucity of pathognomonic features and limited diagnostics, but the scenario of patients presenting en masse with a similar pulmonary syndrome should alert the clinician to the possibility of aerosolized toxin exposure. As knowledge of these agents increases, so too should the capabilities for detection,protection, diagnosis, and therapy. This improved understanding, coupled with ongoing public education and awareness and with detailed proactive planning will provide the framework for a prepared community. PMID:15062231

  9. EMP coupling to ships

    SciTech Connect

    Deadrick, F.J.; Cabayan, H.S.; Kunz, K.F.; Bevensee, R.M.; Martin, L.C.; Egbert, R.W.

    1980-01-01

    Scale-model tests were conducted to establish the adequacy and limitations of model measurements as tools for predicting electromagnetic pulse (EMP) coupling voltages and currents to the critical antennas, cables, and metallic structures on ships. The scale-model predictions are compared with the results of the full-scale EMP simulation test of the Canadian ASW ship, HMCS Huron. (The EMP coupling predictions in this report were made without prior knowledge of the results of the data from the HMCS Huron tests.) This report establishes that the scale-model tests in conjunction with the data base from EMP coupling modules provides the necessary information for source model development and permits effective, low-cost study of particular system configurations. 184 figures, 9 tables.

  10. Coupled wedge waves.

    PubMed

    Abell, Bradley C; Pyrak-Nolte, Laura J

    2013-11-01

    The interface between two wedges can be treated as a displacement discontinuity characterized by elastic stiffnesses. By representing the boundary between the two quarter-spaces as a displacement discontinuity, coupled wedge waves were determined theoretically to be dispersive and to depend on the specific stiffness of the non-welded contact between the two wedges. Laboratory experiments on isotropic and anisotropic aluminum confirmed the theoretical prediction that the velocity of coupled wedge waves, for a non-welded interface, ranged continuously from the single wedge wave velocity at low stress to the Rayleigh velocity as the load applied normal to the interface was increased. Elastic waves propagating along the coupled wedges of two quarter-spaces in non-welded contact are found to exist theoretically even when the material properties of the two quarter-spaces are the same. PMID:24180766

  11. Tube coupling device

    NASA Technical Reports Server (NTRS)

    Myers, William N. (Inventor); Hein, Leopold A. (Inventor)

    1987-01-01

    A first annular ring of a tube coupling device has a keyed opening sized to fit around the nut region of a male coupling, and a second annular ring has a keyed opening sized to fit around the nut of a female coupling. Each ring has mating ratchet teeth and these rings are biased together, thereby engaging these teeth and preventing rotation of these rings. This in turn prevents the rotation of the male nut region with respect to the female nut. For tube-to-bulkhead locking, one facet of one ring is notched, and a pin is pressed into an opening in the bulkhead. This pin is sized to fit within one of the notches in the ring, thereby preventing rotation of this ring with respect to the bulkhead.

  12. Intraperitoneal contrast agents for computed tomography

    SciTech Connect

    Stork, J.

    1985-08-01

    Intraperitoneal contrast agents have been used to diagnose mass lesions, adhesions, and hernias using conventional radiographic techniques. The use of intraperitoneal contrast agents in conjunction with computed tomography (CT) has been limited and is the subject of this report.

  13. What Are Anticoagulants and Antiplatelet Agents?

    MedlinePLUS

    ANSWERS by heart Treatments + Tests What Are Anticoagulants and Antiplatelet Agents? Anticoagulants and antiplatelet agents are medicines that reduce blood clotting in an artery, a vein or the heart. Blood clots ...

  14. Learning other agents` preferences in multiagent negotiation

    SciTech Connect

    Bui, H.H.; Kieronska, D.; Venkatesh, S.

    1996-12-31

    In multiagent systems, an agent does not usually have complete information about the preferences and decision making processes of other agents. This might prevent the agents from making coordinated choices, purely due to their ignorance of what others want. This paper describes the integration of a learning module into a communication-intensive negotiating agent architecture. The learning module gives the agents the ability to learn about other agents` preferences via past interactions. Over time, the agents can incrementally update their models of other agents` preferences and use them to make better coordinated decisions. Combining both communication and learning, as two complement knowledge acquisition methods, helps to reduce the amount of communication needed on average, and is justified in situations where communication is computationally costly or simply not desirable (e.g. to preserve the individual privacy).

  15. Intelligent Agents as Cognitive Tools for Education.

    ERIC Educational Resources Information Center

    Baylor, Amy

    1999-01-01

    Examines the educational potential for intelligent agents as cognitive tools. Discusses the role of intelligent agents: managing large amounts of information (information overload), serving as a pedagogical expert, and creating programming environments for the learner. (AEF)

  16. Soft Tissue Sarcomas and Agent Orange

    MedlinePLUS

    ... Toll Free Numbers VA » Health Care » Public Health » Military Exposures » Agent Orange » Veterans' Diseases Associated with Agent ... Health Menu Menu Public Health Public Health Home Military Exposures Military Exposures Home 4 Ways to Find ...

  17. Porphyria Cutanea Tarda and Agent Orange

    MedlinePLUS

    ... Toll Free Numbers VA » Health Care » Public Health » Military Exposures » Agent Orange » Veterans' Diseases Associated with Agent ... Health Menu Menu Public Health Public Health Home Military Exposures Military Exposures Home 4 Ways to Find ...

  18. Chemopreventive Agent Development | Division of Cancer Prevention

    Cancer.gov

    This group promotes and supports research on early chemopreventive agent development, from preclinical studies to phas | Research on early chemopreventive agent development, from preclinical studies to phase I clinical trials.

  19. Intelligent Agent Architectures: Reactive Planning Testbed

    NASA Technical Reports Server (NTRS)

    Rosenschein, Stanley J.; Kahn, Philip

    1993-01-01

    An Integrated Agent Architecture (IAA) is a framework or paradigm for constructing intelligent agents. Intelligent agents are collections of sensors, computers, and effectors that interact with their environments in real time in goal-directed ways. Because of the complexity involved in designing intelligent agents, it has been found useful to approach the construction of agents with some organizing principle, theory, or paradigm that gives shape to the agent's components and structures their relationships. Given the wide variety of approaches being taken in the field, the question naturally arises: Is there a way to compare and evaluate these approaches? The purpose of the present work is to develop common benchmark tasks and evaluation metrics to which intelligent agents, including complex robotic agents, constructed using various architectural approaches can be subjected.

  20. Coupling gravitons to matter.

    PubMed

    Bern, Z; De Freitas, A; Wong, H L

    2000-04-17

    Using relationships between open and closed strings, we present a construction of tree-level scattering amplitudes for gravitons minimally coupled to matter in terms of gauge theory partial amplitudes. In particular, we present examples of amplitudes with gravitons coupled to vectors or to a single fermion pair. We also present two examples with massive graviton exchange, as would arise in the presence of large compact dimensions. The gauge charges are represented by flavors of dynamical scalars or fermions. This also leads to an unconventional decomposition of color and kinematics in gauge theories. PMID:11019138

  1. Goldstino couplings to matter

    SciTech Connect

    Clark, T.E.; Love, S.T.

    1996-11-01

    A nonlinearly realized supersymmetric action describing the invariant couplings of the Goldstino to matter is constructed. Using the Akulov-Volkov Lagrangian, any operator can be made part of a supersymmetric-invariant action. Of particular interest are interaction terms which include the product of the Akulov-Volkov Lagrangian with the ordinary matter Lagrangian as well as the coupling of the product of the covariant derivative of the Goldstino field to the matter supersymmetry current. The latter is the lowest dimensional operator linear in the Goldstino field. A Goldstino Goldberger-Treiman relation is established and shown to be satisfied by the effective action. {copyright} {ital 1996 The American Physical Society.}

  2. Dynamics of coupled human-landscape systems

    NASA Astrophysics Data System (ADS)

    Werner, B. T.; McNamara, D. E.

    2007-11-01

    A preliminary dynamical analysis of landscapes and humans as hierarchical complex systems suggests that strong coupling between the two that spreads to become regionally or globally pervasive should be focused at multi-year to decadal time scales. At these scales, landscape dynamics is dominated by water, sediment and biological routing mediated by fluvial, oceanic, atmospheric processes and human dynamics is dominated by simplifying, profit-maximizing market forces and political action based on projection of economic effect. Also at these scales, landscapes impact humans through patterns of natural disasters and trends such as sea level rise; humans impact landscapes by the effect of economic activity and changes meant to mitigate natural disasters and longer term trends. Based on this analysis, human-landscape coupled systems can be modeled using heterogeneous agents employing prediction models to determine actions to represent the nonlinear behavior of economic and political systems and rule-based routing algorithms to represent landscape processes. A cellular model for the development of New Orleans illustrates this approach, with routing algorithms for river and hurricane-storm surge determining flood extent, five markets (home, labor, hotel, tourism and port services) connecting seven types of economic agents (home buyers/laborers, home developers, hotel owners/ employers, hotel developers, tourists, port services developer and port services owners/employers), building of levees or a river spillway by political agents and damage to homes, hotels or port services within cells determined by the passage or depth of flood waters. The model reproduces historical aspects of New Orleans economic development and levee construction and the filtering of frequent small-scale floods at the expense of large disasters.

  3. Pathogenic agents in freshwater resources

    NASA Astrophysics Data System (ADS)

    Geldreich, Edwin E.

    1996-02-01

    Numerous pathogenic agents have been found in freshwaters used as sources for water supplies, recreational bathing and irrigation. These agents include bacterial pathogens, enteric viruses, several protozoans and parasitic worms more common to tropical waters. Although infected humans are a major source of pathogens, farm animals (cattle, sheep, pigs), animal pets (dogs, cats) and wildlife serve as significant reservoirs and should not be ignored. The range of infected individuals within a given warm-blooded animal group (humans included) may range from 1 to 25%. Survival times for pathogens in the water environment may range from a few days to as much as a year (Ascaris, Taenia eggs), with infective dose levels varying from one viable cell for several primary pathogenic agents to many thousands of cells for a given opportunistic pathogen.As pathogen detection in water is complex and not readily incorporated into routine monitoring, a surrogate is necessary. In general, indicators of faecal contamination provide a positive correlation with intestinal pathogen occurrences only when appropriate sample volumes are examined by sensitive methodology.Pathways by which pathogens reach susceptible water users include ingestion of contaminated water, body contact with polluted recreational waters and consumption of salad crops irrigated by polluted freshwaters. Major contributors to the spread of various water-borne pathogens are sewage, polluted surface waters and stormwater runoff. All of these contributions are intensified during periods of major floods. Several water-borne case histories are cited as examples of breakdowns in public health protection related to water supply, recreational waters and the consumption of contaminated salad crops. In the long term, water resource management must focus on pollution prevention from point sources of waste discharges and the spread of pathogens in watershed stormwater runoff.

  4. Honey - A Novel Antidiabetic Agent

    PubMed Central

    Erejuwa, Omotayo O.; Sulaiman, Siti A.; Wahab, Mohd S. Ab

    2012-01-01

    Diabetes mellitus remains a burden worldwide in spite of the availability of numerous antidiabetic drugs. Honey is a natural substance produced by bees from nectar. Several evidence-based health benefits have been ascribed to honey in the recent years. In this review article, we highlight findings which demonstrate the beneficial or potential effects of honey in the gastrointestinal tract (GIT), on the gut microbiota, in the liver, in the pancreas and how these effects could improve glycemic control and metabolic derangements. In healthy subjects or patients with impaired glucose tolerance or diabetes mellitus, various studies revealed that honey reduced blood glucose or was more tolerable than most common sugars or sweeteners. Pre-clinical studies provided more convincing evidence in support of honey as a potential antidiabetic agent than clinical studies did. The not-too-impressive clinical data could mainly be attributed to poor study designs or due to the fact that the clinical studies were preliminary. Based on the key constituents of honey, the possible mechanisms of action of antidiabetic effect of honey are proposed. The paper also highlights the potential impacts and future perspectives on the use of honey as an antidiabetic agent. It makes recommendations for further clinical studies on the potential antidiabetic effect of honey. This review provides insight on the potential use of honey, especially as a complementary agent, in the management of diabetes mellitus. Hence, it is very important to have well-designed, randomized controlled clinical trials that investigate the reproducibility (or otherwise) of these experimental data in diabetic human subjects. PMID:22811614

  5. Fostering Multimedia Learning of Science: Exploring the Role of an Animated Agent's Image

    ERIC Educational Resources Information Center

    Dunsworth, Qi; Atkinson, Robert K.

    2007-01-01

    Research suggests that students learn better when studying a picture coupled with narration rather than on-screen text in a computer-based multimedia learning environment. Moreover, combining narration with the visual presence of an animated pedagogical agent may also encourage students to process information deeper than narration or on-screen…

  6. Radioactive scanning agents with hydroquinone stabilizer

    SciTech Connect

    Whitehouse, H.S.

    1980-10-21

    Stable compositions, useful as technetium-99m-based scintigraphic agents, comprise hydroquinone in combination with a pertechnetate reducing agent or dissolved in pertechnetate-99m (99mtco4-) solution. The compositions are especially useful in combination with a phosphate or phosphonate material which carries the radionuclide to bone, thus providing a skeletal imaging agent.

  7. Infants Attribute to Agents Goals and Dispositions

    ERIC Educational Resources Information Center

    Luo, Yuyan; Choi, You-jung

    2012-01-01

    This commentary article is to be published alongside: Hernik, M., & Southgate, V. (2012). What do infants know about agents' goals? The authors see this issue consisting of two closely related questions. First, what is an agent to infants? Second, how do infants attribute goals to agents? Hernik and Southgage (H&S) focused on the second question.…

  8. Agent-based modeling of complex infrastructures

    SciTech Connect

    North, M. J.

    2001-06-01

    Complex Adaptive Systems (CAS) can be applied to investigate complex infrastructures and infrastructure interdependencies. The CAS model agents within the Spot Market Agent Research Tool (SMART) and Flexible Agent Simulation Toolkit (FAST) allow investigation of the electric power infrastructure, the natural gas infrastructure and their interdependencies.

  9. Construction and Evaluation of Animated Teachable Agents

    ERIC Educational Resources Information Center

    Bodenheimer, Bobby; Williams, Betsy; Kramer, Mattie Ruth; Viswanath, Karun; Balachandran, Ramya; Belynne, Kadira; Biswas, Gautam

    2009-01-01

    This article describes the design decisions, technical approach, and evaluation of the animation and interface components for an agent-based system that allows learners to learn by teaching. Students learn by teaching an animated agent using a visual representation. The agent can answer questions about what she has been taught and take quizzes.…

  10. 24 CFR 232.1011 - Management agents.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 24 Housing and Urban Development 2 2013-04-01 2013-04-01 false Management agents. 232.1011 Section... Management agents. (a) An operator or borrower may, with the prior written approval of HUD, execute a management agent agreement setting forth the duties and procedures for matters related to the management...

  11. 24 CFR 232.1011 - Management agents.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 24 Housing and Urban Development 2 2014-04-01 2014-04-01 false Management agents. 232.1011 Section... Management agents. (a) An operator or borrower may, with the prior written approval of HUD, execute a management agent agreement setting forth the duties and procedures for matters related to the management...

  12. Beyond Butlers: Intelligent Agents as Mentors.

    ERIC Educational Resources Information Center

    Baylor, Amy

    2000-01-01

    Discusses pedagogical issues for intelligent agents to successfully serve as mentors for educational purposes. Examines broader issues about the nature or persona necessary for an intelligent agent as mentor, incorporating usability and human-computer interaction issues such as the anthropomorphic qualities of the agent and the social relationship…

  13. Online Deception Detection Using BDI Agents

    ERIC Educational Resources Information Center

    Merritts, Richard A.

    2013-01-01

    This research has two facets within separate research areas. The research area of Belief, Desire and Intention (BDI) agent capability development was extended. Deception detection research has been advanced with the development of automation using BDI agents. BDI agents performed tasks automatically and autonomously. This study used these…

  14. Online Deception Detection Using BDI Agents

    ERIC Educational Resources Information Center

    Merritts, Richard A.

    2013-01-01

    This research has two facets within separate research areas. The research area of Belief, Desire and Intention (BDI) agent capability development was extended. Deception detection research has been advanced with the development of automation using BDI agents. BDI agents performed tasks automatically and autonomously. This study used these…

  15. STUDIES OF WATERBORNE AGENTS OF VIRAL GASTROENTERITIS

    EPA Science Inventory

    The etiologic agent of a large outbreak of waterborne viral gastroenteritis was detected employing immune electron microscopy (IEM) and a newly developed solid phase radioimmunoassay (RIA). This agent, referred to as the Snow Mountain Agent (SMA), is 27-32 nm. in diameter, has cu...

  16. 46 CFR Sec. 2 - General Agent's requirements.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 8 2011-10-01 2011-10-01 false General Agent's requirements. Sec. 2 Section 2 Shipping MARITIME ADMINISTRATION, DEPARTMENT OF TRANSPORTATION A-NATIONAL SHIPPING AUTHORITY SLOP CHESTS Sec. 2 General Agent's requirements. The General Agent shall: (a) Obtain from the Master, a requisition for...

  17. 46 CFR Sec. 2 - General Agent's requirements.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 8 2010-10-01 2010-10-01 false General Agent's requirements. Sec. 2 Section 2 Shipping MARITIME ADMINISTRATION, DEPARTMENT OF TRANSPORTATION A-NATIONAL SHIPPING AUTHORITY SLOP CHESTS Sec. 2 General Agent's requirements. The General Agent shall: (a) Obtain from the Master, a requisition for...

  18. 46 CFR Sec. 2 - General Agent's requirements.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 8 2013-10-01 2013-10-01 false General Agent's requirements. Sec. 2 Section 2 Shipping MARITIME ADMINISTRATION, DEPARTMENT OF TRANSPORTATION A-NATIONAL SHIPPING AUTHORITY SLOP CHESTS Sec. 2 General Agent's requirements. The General Agent shall: (a) Obtain from the Master, a requisition for...

  19. 46 CFR Sec. 2 - General Agent's requirements.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 8 2012-10-01 2012-10-01 false General Agent's requirements. Sec. 2 Section 2 Shipping MARITIME ADMINISTRATION, DEPARTMENT OF TRANSPORTATION A-NATIONAL SHIPPING AUTHORITY SLOP CHESTS Sec. 2 General Agent's requirements. The General Agent shall: (a) Obtain from the Master, a requisition for...

  20. 46 CFR Sec. 2 - General Agent's requirements.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 8 2014-10-01 2014-10-01 false General Agent's requirements. Sec. 2 Section 2 Shipping MARITIME ADMINISTRATION, DEPARTMENT OF TRANSPORTATION A-NATIONAL SHIPPING AUTHORITY SLOP CHESTS Sec. 2 General Agent's requirements. The General Agent shall: (a) Obtain from the Master, a requisition for...

  1. Hydroxypyridonate chelating agents and synthesis thereof

    DOEpatents

    Raymond, K.N.; Scarrow, R.C.; White, D.L.

    1985-11-12

    Chelating agents having 1-hydroxy-2-pyridinone (HOPO) and related moieties incorporated within their structures, including polydentate HOPO-substituted polyamines such as spermidine and spermine, and HOPO-substituted desferrioxamine. The chelating agents are useful in selectively removing certain cations from solution, and are particularly useful as ferric ion and actinide chelators. Novel syntheses of the chelating agents are provided. 4 tabs.

  2. Method For Detecting Biological Agents

    DOEpatents

    Chen, Liaohai (Los Alamos, NM); McBranch, Duncan W. (Santa Fe, NM); Wang, Hsing-Lin (Los Alamos, NM); Whitten, David G. (Santa Fe, NM)

    2005-12-27

    A sensor is provided including a polymer capable of having an alterable measurable property from the group of luminescence and electrical conductivity, the polymer having an intermediate combination of a recognition element, a tethering element and a property-altering element bound thereto and capable of altering the measurable property, the intermediate combination adapted for subsequent separation from the polymer upon exposure to an agent having an affinity for binding to the recognition element whereupon the separation of the intermediate combination from the polymer results in a detectable change in the alterable measurable property, and, detecting said detectable change in the alterable measurable property.

  3. Antimicrobial agents from Heterotheca inuloides.

    PubMed

    Kubo, I; Muroi, H; Kubo, A; Chaudhuri, S K; Sanchez, Y; Ogura, T

    1994-06-01

    By bioassay directed fractionation, four sesquiterpenoids 1-4 were isolated as antimicrobial agents from the dried flowers of Heterotheca inuloides, a Mexican medicinal plant locally known as "arnica". 7-Hydroxy-3,4-dihydrocadalin (3) and 7-hydroxycadalin (4) exhibited potent antibacterial activity against Gram-positive bacteria with minimum inhibitory concentrations (MICs) ranging from 6.25 to 12.5 micrograms/ml. Notably, 7-hydroxy-3,4-dihydrocadalin showed bactericidal activity against methicillin-resistant Staphylococcus aureus (MRSA) with a minimum bactericidal concentration (MBC) of 12.5 micrograms/ml. PMID:8073086

  4. Investigating biocomplexity through the agent-based paradigm

    PubMed Central

    Kaul, Himanshu

    2015-01-01

    Capturing the dynamism that pervades biological systems requires a computational approach that can accommodate both the continuous features of the system environment as well as the flexible and heterogeneous nature of component interactions. This presents a serious challenge for the more traditional mathematical approaches that assume component homogeneity to relate system observables using mathematical equations. While the homogeneity condition does not lead to loss of accuracy while simulating various continua, it fails to offer detailed solutions when applied to systems with dynamically interacting heterogeneous components. As the functionality and architecture of most biological systems is a product of multi-faceted individual interactions at the sub-system level, continuum models rarely offer much beyond qualitative similarity. Agent-based modelling is a class of algorithmic computational approaches that rely on interactions between Turing-complete finite-state machines—or agents—to simulate, from the bottom-up, macroscopic properties of a system. In recognizing the heterogeneity condition, they offer suitable ontologies to the system components being modelled, thereby succeeding where their continuum counterparts tend to struggle. Furthermore, being inherently hierarchical, they are quite amenable to coupling with other computational paradigms. The integration of any agent-based framework with continuum models is arguably the most elegant and precise way of representing biological systems. Although in its nascence, agent-based modelling has been utilized to model biological complexity across a broad range of biological scales (from cells to societies). In this article, we explore the reasons that make agent-based modelling the most precise approach to model biological systems that tend to be non-linear and complex. PMID:24227161

  5. Investigating biocomplexity through the agent-based paradigm.

    PubMed

    Kaul, Himanshu; Ventikos, Yiannis

    2015-01-01

    Capturing the dynamism that pervades biological systems requires a computational approach that can accommodate both the continuous features of the system environment as well as the flexible and heterogeneous nature of component interactions. This presents a serious challenge for the more traditional mathematical approaches that assume component homogeneity to relate system observables using mathematical equations. While the homogeneity condition does not lead to loss of accuracy while simulating various continua, it fails to offer detailed solutions when applied to systems with dynamically interacting heterogeneous components. As the functionality and architecture of most biological systems is a product of multi-faceted individual interactions at the sub-system level, continuum models rarely offer much beyond qualitative similarity. Agent-based modelling is a class of algorithmic computational approaches that rely on interactions between Turing-complete finite-state machines--or agents--to simulate, from the bottom-up, macroscopic properties of a system. In recognizing the heterogeneity condition, they offer suitable ontologies to the system components being modelled, thereby succeeding where their continuum counterparts tend to struggle. Furthermore, being inherently hierarchical, they are quite amenable to coupling with other computational paradigms. The integration of any agent-based framework with continuum models is arguably the most elegant and precise way of representing biological systems. Although in its nascence, agent-based modelling has been utilized to model biological complexity across a broad range of biological scales (from cells to societies). In this article, we explore the reasons that make agent-based modelling the most precise approach to model biological systems that tend to be non-linear and complex. PMID:24227161

  6. Tangleproof Rotary Electrical Coupling

    NASA Technical Reports Server (NTRS)

    Keller, F.

    1983-01-01

    New rotary coupling connects large number of electrical cables to turntable without stressing cables or tangling them. Device accommodates 246 cables containing total of 758 conductors and allows turntable to rotate through arc of 320 degrees. At extremes of rotation, cables are loose enough that they are not pulled taut and overstressed. At halfway point, cables are not so loose that they become entangled.

  7. Coupled Oscillators with Chemotaxis

    NASA Astrophysics Data System (ADS)

    Sawai, Satoshi; Aizawa, Yoji

    1998-08-01

    A simple coupled oscillator system with chemotaxis is introducedto study morphogenesis of cellular slime molds. The modelsuccessfuly explains the migration of pseudoplasmodium which hasbeen experimentally predicted to be lead by cells with higherintrinsic frequencies. Results obtained predict that its velocityattains its maximum value in the interface region between totallocking and partial locking and also suggest possible rolesplayed by partial synchrony during multicellular development.

  8. Too Many Couples

    ERIC Educational Resources Information Center

    Kay, Joseph

    2007-01-01

    In this article, the author offers his ad hoc reflections on the question of just how many academic couples a department could comfortably accommodate from the point of view of good governance, in the hope of getting an honest dialogue started and seeing some reasonable guidelines eventually created by one organization or another as a result. He…

  9. Nominalizations in Couple Counseling.

    ERIC Educational Resources Information Center

    Green, David B.

    1979-01-01

    Presents a discussion of the linguistic mechansim of nominalization. In identifying and challenging nominalizations, the counselor can help a couple clarify the present state of their relationship, where they are hurting, the desired state of their relationship, and the feeling and behavioral changes they want in their relationship. (Author)

  10. Mobile agent location in distributed environments

    NASA Astrophysics Data System (ADS)

    Fountoukis, S. G.; Argyropoulos, I. P.

    2012-12-01

    An agent is a small program acting on behalf of a user or an application which plays the role of a user. Artificial intelligence can be encapsulated in agents so that they can be capable of both behaving autonomously and showing an elementary decision ability regarding movement and some specific actions. Therefore they are often called autonomous mobile agents. In a distributed system, they can move themselves from one processing node to another through the interconnecting network infrastructure. Their purpose is to collect useful information and to carry it back to their user. Also, agents are used to start, monitor and stop processes running on the individual interconnected processing nodes of computer cluster systems. An agent has a unique id to discriminate itself from other agents and a current position. The position can be expressed as the address of the processing node which currently hosts the agent. Very often, it is necessary for a user, a processing node or another agent to know the current position of an agent in a distributed system. Several procedures and algorithms have been proposed for the purpose of position location of mobile agents. The most basic of all employs a fixed computing node, which acts as agent position repository, receiving messages from all the moving agents and keeping records of their current positions. The fixed node, responds to position queries and informs users, other nodes and other agents about the position of an agent. Herein, a model is proposed that considers pairs and triples of agents instead of single ones. A location method, which is investigated in this paper, attempts to exploit this model.

  11. Ruthenium complexes as antimicrobial agents.

    PubMed

    Li, Fangfei; Collins, J Grant; Keene, F Richard

    2015-04-21

    One of the major advances in medical science has been the development of antimicrobials; however, a consequence of their widespread use has been the emergence of drug-resistant populations of microorganisms. There is clearly a need for the development of new antimicrobials--but more importantly, there is the need for the development of new classes of antimicrobials, rather than drugs based upon analogues of known scaffolds. Due to the success of the platinum anticancer agents, there has been considerable interest in the development of therapeutic agents based upon other transition metals--and in particular ruthenium(II/III) complexes, due to their well known interaction with DNA. There have been many studies of the anticancer properties and cellular localisation of a range of ruthenium complexes in eukaryotic cells over the last decade. However, only very recently has there been significant interest in their antimicrobial properties. This review highlights the types of ruthenium complexes that have exhibited significant antimicrobial activity and discusses the relationship between chemical structure and biological processing--including site(s) of intracellular accumulation--of the ruthenium complexes in both bacterial and eukaryotic cells. PMID:25724019

  12. Biologic agents in systemic vasculitis

    PubMed Central

    Henderson, Charles F; Seo, Philip

    2012-01-01

    The treatment of systemic necrotizing vasculitis has made great strides in both efficacy and outcomes. Standard therapies, however, are associated with numerous side effects, and not all patients will respond to conventional immunosuppression. These realities have prompted the search for safer and more efficacious treatments, most notably among biologic agents. For example, the role of TNF-α in the pathophysiology of several vasculitides has led to the investigation of targeted inhibitors of this cytokine, albeit with mixed results. There have been some disappointing results in the area of giant cell arteritis and Wegener’s granulomatosis (granulomatosis with polygiitis), but anti-TNF therapy has shown promise in the treatment of Takayasu’s arteritis, although additional trials to demonstrate its efficacy are required. Anti-B-cell therapy seems to be the most promising advance in the management of these diseases. Complete and partial responses have been seen in both primary and secondary mixed cryoglobulinemic vasculitis. Recent trials have demonstrated that rituximab is effective for the treatment of Wegener’s granulomatosis and microscopic polyangiitis. These trials have, however, raised concerns regarding the long-term safety of these agents. The future holds promise for additional targeted therapies with improved patient response and fewer side effects. PMID:23785387

  13. A Review of Luting Agents

    PubMed Central

    Pameijer, Cornelis H.

    2012-01-01

    Due to the availability of a large number of luting agents (dental cements) proper selection can be a daunting task and is usually based on a practitioner's reliance on experience and preference and less on in depth knowledge of materials that are used for the restoration and luting agent properties. This review aims at presenting an overview of current cements and discusses physical properties, biocompatibility and other properties that make a particular cement the preferred choice depending on the clinical indication. Tables are provided that outline the different properties of the generic classification of cements. It should be noted that no recommendations are made to use a particular commercial cement for a hypothetical clinical situation. The choice is solely the responsibility of the practitioner. The appendix is intended as a guide for the practitioner towards a recommended choice under commonly encountered clinical scenarios. Again, no commercial brands are recommended although the author recognizes that some have better properties than others. Please note that this flowchart strictly presents the author's opinion and is based on research, clinical experience and the literature. PMID:22505909

  14. Surfactants as blackbird stressing agents

    USGS Publications Warehouse

    Lefebvre, P.W.; Seubert, J.L.

    1970-01-01

    Applications of wetting-agent solutions produce mortality in birds. The exact cause of death is undetermined but it is believed that destruction of the insulating qualities of the plumage permits ambient cold temperatures and evaporation to lower the body temperature to a lethal level. The original concept of using these materials as bird-control tools was developed in 1958 at the Patuxent Wildlife Research Center, Bureau of Sport Fisheries and Wildlife Laurel, Maryland. Early field trials by personnel of the Division of Wildlife Services and the Denver Wildlife Research Center indicated that ground-application techniques had promise but limitations of the equipment precluded successful large-scale roost treatments. In 1966, Patuxent Center personnel began using tanker-type aircraft to evaluate high-volume aerial applications of wetting agents. The success of these tests led to the use of small aircraft to make low-volume, high-concentration aerial applications just prior to expected rainfall. Recent trials of the low-volume method show that, with some limitations, it is effective, inexpensive, and safe to the environment. Current research emphasizes the screening of new candidate materials for efficacy, biodegradability, and toxicity to plants and non-target animals, as well as basic investigations of the avian physiological mechanisms involved. Field trials to develop more effective application techniques will continue.

  15. Triazole: A Promising Antitubercular Agent.

    PubMed

    Keri, Rangappa S; Patil, Siddappa A; Budagumpi, Srinivasa; Nagaraja, Bhari Mallanna

    2015-10-01

    Tuberculosis is a contagious disease with comparatively high mortality worldwide. The statistics shows that around three million people throughout the world die annually from tuberculosis and there are around eight million new cases each year, of which developing countries showed major share. Therefore, the discovery and development of effective antituberculosis drugs with novel mechanism of action have become an insistent task for infectious diseases research programs. The literature reveals that, heterocyclic moieties have drawn attention of the chemists, pharmacologists, microbiologists, and other researchers owing to its indomitable biological potential as anti-infective agents. Among heterocyclic compounds, triazole (1,2,3-triazole/1,2,4-triazole) nucleus is one of the most important and well-known heterocycles, which is a common and integral feature of a variety of natural products and medicinal agents. Triazole core is considered as a privileged structure in medicinal chemistry and is widely used as 'parental' compounds to synthesize molecules with medical benefits, especially with infection-related activities. In the present review, we have collated published reports on this versatile core to provide an insight so that its complete therapeutic potential can be utilized for the treatment of tuberculosis. This review also explores triazole as a potential targeted core moiety against tuberculosis and various research ongoing worldwide. It is hoped that this review will be helpful for new thoughts in the quest for rational designs of more active and less toxic triazole-based antituberculosis drugs. PMID:25643871

  16. Electric power market agent design

    NASA Astrophysics Data System (ADS)

    Oh, Hyungseon

    The electric power industry in many countries has been restructured in the hope of a more economically efficient system. In the restructured system, traditional operating and planning tools based on true marginal cost do not perform well since information required is strictly confidential. For developing a new tool, it is necessary to understand offer behavior. The main objective of this study is to create a new tool for power system planning. For the purpose, this dissertation develops models for a market and market participants. A new model is developed in this work for explaining a supply-side offer curve, and several variables are introduced to characterize the curve. Demand is estimated using a neural network, and a numerical optimization process is used to determine the values of the variables that maximize the profit of the agent. The amount of data required for the optimization is chosen with the aid of nonlinear dynamics. To suggest an optimal demand-side bidding function, two optimization problems are constructed and solved for maximizing consumer satisfaction based on the properties of two different types of demands: price-based demand and must-be-served demand. Several different simulations are performed to test how an agent reacts in various situations. The offer behavior depends on locational benefit as well as the offer strategies of competitors.

  17. Nanoparticle-based theranostic agents

    PubMed Central

    Xie, Jin; Lee, Seulki; Chen, Xiaoyuan

    2010-01-01

    Theranostic nanomedicine is emerging as a promising therapeutic paradigm. It takes advantage of the high capacity of nanoplatforms to ferry cargo and loads onto them both imaging and therapeutic functions. The resulting nanosystems, capable of diagnosis, drug delivery and monitoring of therapeutic response, are expected to play a significant role in the dawning era of personalized medicine, and much research effort has been devoted toward that goal. A convenience in constructing such function-integrated agents is that many nanoplatforms are already, themselves, imaging agents. Their well developed surface chemistry makes it easy to load them with pharmaceutics and promote them to be theranostic nanosystems. Iron oxide nanoparticles, quantum dots, carbon nanotubes, gold nanoparticles and silica nanoparticles, have been previously well investigated in the imaging setting and are candidate nanoplatforms for building up nanoparticle-based theranostics. In the current article, we will outline the progress along this line, organized by the category of the core materials. We will focus on construction strategies and will discuss the challenges and opportunities associated with this emerging technology. PMID:20691229

  18. Reversal agents in anaesthesia and critical care.

    PubMed

    Pani, Nibedita; Dongare, Pradeep A; Mishra, Rajeeb Kumar

    2015-10-01

    Despite the advent of short and ultra-short acting drugs, an in-depth knowledge of the reversal agents used is a necessity for any anaesthesiologist. Reversal agents are defined as any drug used to reverse the effects of anaesthetics, narcotics or potentially toxic agents. The controversy on the routine reversal of neuromuscular blockade still exists. The advent of newer reversal agents like sugammadex have made the use of steroidal neuromuscular blockers like rocuronium feasible in rapid sequence induction situations. We made a review of the older reversal agents and those still under investigation for drugs that are regularly used in our anaesthesia practice. PMID:26644615

  19. Achieving agent coordination via distributed preferences

    SciTech Connect

    D`Ambrosio, J.G.; Birmingham, W.P.

    1996-12-31

    Agent-based systems provide hope for solving a wide variety of distributed problems. One key aspect of agent-based system is coordinating agent actions to achieve coherent behavior. For example, in concurrent engineering (CE), it is necessary to ensure that the individual decision made by constituents in a design organization achieve overall organizational objectives (e.g., increase market share), while still allowing individuals to exploit their expertise. We believe CE is representative of many multi-agent problems, in that agent coordination must include facilities to support both solving a hierarchically decomposed problem, e.g., the contract net, and interactions among peers as well.

  20. Anchor Toolkit - a secure mobile agent system

    SciTech Connect

    Mudumbai, Srilekha S.; Johnston, William; Essiari, Abdelilah

    1999-05-19

    Mobile agent technology facilitates intelligent operation insoftware systems with less human interaction. Major challenge todeployment of mobile agents include secure transmission of agents andpreventing unauthorized access to resources between interacting systems,as either hosts, or agents, or both can act maliciously. The Anchortoolkit, designed by LBNL, handles the transmission and secure managementof mobile agents in a heterogeneous distributed computing environment. Itprovides users with the option of incorporating their security managers.This paper concentrates on the architecture, features, access control anddeployment of Anchor toolkit. Application of this toolkit in a securedistributed CVS environment is discussed as a case study.

  1. Reversal agents in anaesthesia and critical care

    PubMed Central

    Pani, Nibedita; Dongare, Pradeep A; Mishra, Rajeeb Kumar

    2015-01-01

    Despite the advent of short and ultra-short acting drugs, an in-depth knowledge of the reversal agents used is a necessity for any anaesthesiologist. Reversal agents are defined as any drug used to reverse the effects of anaesthetics, narcotics or potentially toxic agents. The controversy on the routine reversal of neuromuscular blockade still exists. The advent of newer reversal agents like sugammadex have made the use of steroidal neuromuscular blockers like rocuronium feasible in rapid sequence induction situations. We made a review of the older reversal agents and those still under investigation for drugs that are regularly used in our anaesthesia practice. PMID:26644615

  2. Nerve agents: implications for anesthesia providers.

    PubMed

    Hrobak, Paula Kay

    2008-04-01

    Anesthesia providers may be called to treat injuries from chemical weapons or spills, for which prompt treatment is vital. It is therefore important to understand the mechanism of action of nerve agents and the resultant pathophysiology and to be able to quickly recognize the signs and symptoms of nerve agent exposure. This review article addresses the different types of nerve agents that are currently being manufactured as well as the symptomatic and definitive treatment of the patient who presents with acute nerve agent toxicity. This article also reviews the physiology of the neuromuscular junction and the autonomic nervous system receptors that nerve agent toxicity affects. PMID:18478812

  3. Peptide-based protein capture agents with high affinity, selectivity, and stability as antibody replacements in biodetection assays

    NASA Astrophysics Data System (ADS)

    Coppock, Matthew B.; Farrow, Blake; Warner, Candice; Finch, Amethist S.; Lai, Bert; Sarkes, Deborah A.; Heath, James R.; Stratis-Cullum, Dimitra

    2014-05-01

    Current biodetection assays that employ monoclonal antibodies as primary capture agents exhibit limited fieldability, shelf life, and performance due to batch-to-batch production variability and restricted thermal stability. In order to improve upon the detection of biological threats in fieldable assays and systems for the Army, we are investigating protein catalyzed capture (PCC) agents as drop-in replacements for the existing antibody technology through iterative in situ click chemistry. The PCC agent oligopeptides are developed against known protein epitopes and can be mass produced using robotic methods. In this work, a PCC agent under development will be discussed. The performance, including affinity, selectivity, and stability of the capture agent technology, is analyzed by immunoprecipitation, western blotting, and ELISA experiments. The oligopeptide demonstrates superb selectivity coupled with high affinity through multi-ligand design, and improved thermal, chemical, and biochemical stability due to non-natural amino acid PCC agent design.

  4. 22 CFR 51.22 - Passport agents and passport acceptance agents.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 22 Foreign Relations 1 2014-04-01 2014-04-01 false Passport agents and passport acceptance agents. 51.22 Section 51.22 Foreign Relations DEPARTMENT OF STATE NATIONALITY AND PASSPORTS PASSPORTS Application § 51.22 Passport agents and passport acceptance agents. (a) U.S. citizen employees of...

  5. 22 CFR 51.22 - Passport agents and passport acceptance agents.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 22 Foreign Relations 1 2012-04-01 2012-04-01 false Passport agents and passport acceptance agents. 51.22 Section 51.22 Foreign Relations DEPARTMENT OF STATE NATIONALITY AND PASSPORTS PASSPORTS Application § 51.22 Passport agents and passport acceptance agents. (a) U.S. citizen employees of...

  6. 22 CFR 51.22 - Passport agents and passport acceptance agents.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 22 Foreign Relations 1 2013-04-01 2013-04-01 false Passport agents and passport acceptance agents. 51.22 Section 51.22 Foreign Relations DEPARTMENT OF STATE NATIONALITY AND PASSPORTS PASSPORTS Application § 51.22 Passport agents and passport acceptance agents. (a) U.S. citizen employees of...

  7. 22 CFR 51.22 - Passport agents and passport acceptance agents.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... Application § 51.22 Passport agents and passport acceptance agents. (a) U.S. citizen employees of the... Department will designate a person described in § 51.22(b) as a passport acceptance agent, his or her... responsibility involving public trust. (d) Training. A passport acceptance agent described in § 51.22(b) must...

  8. Deaths due to unknown foodborne agents.

    PubMed

    Frenzen, Paul D

    2004-09-01

    This study reviews the available evidence on unknown pathogenic agents transmitted in food and examines the methods that have been used to estimate that such agents cause 3,400 deaths per year in the United States. The estimate of deaths was derived from hospital discharge and death certificate data on deaths attributed to gastroenteritis of unknown cause. Fatal illnesses due to unknown foodborne agents do not always involve gastroenteritis, and gastroenteritis may not be accurately diagnosed or reported on hospital charts or death certificates. The death estimate consequently omitted deaths from unknown foodborne agents that do not cause gastroenteritis and likely overstated the number of deaths from agents that cause gastroenteritis. Although the number of deaths from unknown foodborne agents is uncertain, the possible economic cost of these deaths is so large that increased efforts to identify the causal agents are warranted. PMID:15498153

  9. Knowledge Management in Role Based Agents

    NASA Astrophysics Data System (ADS)

    K?r, Hüseyin; Ekinci, Erdem Eser; Dikenelli, Oguz

    In multi-agent system literature, the role concept is getting increasingly researched to provide an abstraction to scope beliefs, norms, goals of agents and to shape relationships of the agents in the organization. In this research, we propose a knowledgebase architecture to increase applicability of roles in MAS domain by drawing inspiration from the self concept in the role theory of sociology. The proposed knowledgebase architecture has granulated structure that is dynamically organized according to the agent's identification in a social environment. Thanks to this dynamic structure, agents are enabled to work on consistent knowledge in spite of inevitable conflicts between roles and the agent. The knowledgebase architecture is also implemented and incorporated into the SEAGENT multi-agent system development framework.

  10. Anomalous gauge boson couplings

    SciTech Connect

    Barklow, T.; Rizzo, T.; Baur, U.

    1997-01-13

    The measurement of anomalous gauge boson self couplings is reviewed for a variety of present and planned accelerators. Sensitivities are compared for these accelerators using models based on the effective Lagrangian approach. The sensitivities described here are for measurement of {open_quotes}generic{close_quotes} parameters {kappa}{sub V}, {lambda}{sub V}, etc., defined in the text. Pre-LHC measurements will not probe these coupling parameters to precision better than O(10{sup -1}). The LHC should be sensitive to better than O(10{sup -2}), while a future NLC should achieve sensitivity of O(10{sup -3}) to O(10{sup -4}) for center of mass energies ranging from 0.5 to 1.5 TeV.

  11. Diboson Production and Couplings

    SciTech Connect

    Burke, Susan E.

    2008-10-01

    We present the most recent cross section measurements for WW and WZ production in proton-antiproton collisions with sqrt(s) = 1.96 TeV at the Fermilab Tevatron in final states with two or three leptons, respectively, along with limits on WWZ triple gauge couplings. We also present the combined search for WW and WZ production in the lepton, neutrino, and dijet final state. Finally, we present ZZ cross section measurements in both the fully leptonic and the two lepton, two neutrino final states along with limits on anomalous couplings ZZZ and ZZgamma. All results presented are based on data collected with the Run II DO and CDF II detectors.

  12. New coupled quintessence cosmology

    SciTech Connect

    Jesus, J. F.; Santos, R. C.; Lima, J. A. S.; Alcaniz, J. S.

    2008-09-15

    A component of dark energy has been recently proposed to explain the current acceleration of the Universe. Unless some unknown symmetry in Nature prevents or suppresses it, such a field may interact with the pressureless component of dark matter, giving rise to the so-called models of coupled quintessence. In this paper we propose a new cosmological scenario where radiation and baryons are conserved, while the dark energy component is decaying into cold dark matter. The dilution of cold dark matter particles, attenuated with respect to the usual a{sup -3} scaling due to the interacting process, is characterized by a positive parameter {epsilon}, whereas the dark energy satisfies the equation of state p{sub x}={omega}{rho}{sub x} ({omega}<0). We carry out a joint statistical analysis involving recent observations from type Ia supernovae, baryon acoustic oscillation peak, and cosmic microwave background shift parameter to check the observational viability of the coupled quintessence scenario here proposed.

  13. Magnetic coupling device

    DOEpatents

    Nance, Thomas A. (Aiken, SC)

    2009-08-18

    A quick connect/disconnect coupling apparatus is provided in which a base member is engaged by a locking housing through a series of interengagement pins. The pins maintain the shaft in a locked position. Upon exposure to an appropriately positioned magnetic field, pins are removed a sufficient distance such that the shaft may be withdrawn from the locking housing. The ability to lock and unlock the connector assembly requires no additional tools or parts apart from a magnetic key.

  14. Object relations couple therapy.

    PubMed

    Scharff, J S; Scharff, D E

    1997-01-01

    The authors describe Fairbairn's view of the personality as a system of parts of self and object in dynamic relation, formed in the context of dependent early relationships and replayed in the intensely intimate and physical relationship of marriage. Through Klein's concept of projective identification, a spouse finds lost parts of the self in the partner, where they may flourish and be reintegrated into the self or they may be held hostage. Marriage is an opportunity for reworking the dynamic relation of parts of the self as they are modified through mutual unconscious interaction with the spouse, but it may become a closed system that inhibits growth of the individual partners. Object relations couple therapy aims to breach the closed system of the unhappy marriage, and offers an enlarged space for understanding that encourages the spouses to provide a better holding environment for each other. Not directive, didactic or symptom-focused, object relations therapy values affect, silence, body language, fantasy, dreams, and transference phenomena as necessary for reaching the unconscious in order to achieve insight. The object relations therapist interprets defenses against anxieties that underlie repetitive patterns of unhelpful behavior, and works toward understanding. As the clinical vignettes show, therapists use countertransference to understand the couple's shared transference from inside their experience. The engine of therapeutic change in this model is the therapist's self. The process of therapy improves the couple's capacity for containing each other's projections instead of refusing to resonate with them or being overtaken by them to the detriment of the self. A cycle of regression and progression in the couple's ability for containment is found as therapy proceeds. The goal of therapy is to enable the projective and introjective identificatory system of the marriage to function with greater concern for the other and respect for the self. PMID:9196784

  15. Quick connect coupling

    NASA Technical Reports Server (NTRS)

    Lomax, Curtis (Inventor); Webbon, Bruce (Inventor)

    1995-01-01

    A cooling apparatus includes a container filled with a quantity of coolant fluid initially cooled to a solid phase, a cooling loop disposed between a heat load and the container, a pump for circulating a quantity of the same type of coolant fluid in a liquid phase through the cooling loop, and a pair of couplings for communicating the liquid phase coolant fluid into the container in a direct interface with the solid phase coolant fluid.

  16. [Use of erythropoiesis stimulating agents].

    PubMed

    Lapierre, A; Souquet, P-J

    2014-02-01

    Anemia is fairly common in lung neoplasms and adequate management can influence both the prognosis and the quality of life of patients. Anemia can stem from diverse mechanisms, and its management must include the search for correctable causes (iron deficiency, inflammation, disease- or treatment-related), and their subsequent treatment. Use of erythropoiesis stimulating agents, namely recombinant erythropoietin, results in hemoglobin increase, fewer blood transfusions, and better quality of life. However, there is also a significant increase in thromboembolic risk associated with this treatment, and their effect on overall survival is still debated. Thus, their use must be restricted to patients treated with palliative intent, receiving chemotherapy but no radiotherapy, with a baseline hemoglobin level under 100 g/L, and target hemoglobin level must not exceed 120 g/L. PMID:24602683

  17. Hexameric Mn(II) Dendrimer as MRI Contrast Agent

    PubMed Central

    Zhu, Jiang; Gale, Eric M.; Atanasova, Iliyana; Rietz, Tyson A.

    2014-01-01

    A Mn(II) chelating dendrimer was prepared as a contrast agent for MRI applications. The dendrimer comprises six tyrosine-derived [Mn(EDTA)(H2O)]2? moieties coupled to a cyclotriphosphazene core. Variable temperature 17O NMR revealed a single water co-ligand per Mn(II) that undergoes fast water exchange (kex = (3.0±0.1) × 108 s?1 at 37 °C). The 37 °C per Mn(II) relaxivity ranged from 8.2 to 3.8 mM?1s?1 from 0.47 to 11.7T, and is 6-fold higher on a per molecule basis. From this field dependence a rotational correlation time was estimated as 0.45±0.02 ns. The imaging and pharmacokinetic properties of the dendrimer were compared to clinically used [Gd(DTPA)(H2O)]2? in mice at 4.7T. On first pass, the higher per ion relaxivity of the dendrimer resulted in 2-fold greater blood signal than for [Gd(DTPA)(H2O)]2?. Blood clearance was fast and elimination occurred through both the renal and hepatobiliary routes. This Mn(II) containing dendrimer represents potential alternative to Gd-based contrast agents, especially in patients with chronic kidney disease where the use of current Gd-based agents may be contraindicated. PMID:25224391

  18. Tuberculosis and nature's pharmacy of putative anti-tuberculosis agents.

    PubMed

    Chinsembu, Kazhila C

    2016-01-01

    Due to the growing problem of drug resistant Mycobacterium tuberculosis strains, coupled with the twinning of tuberculosis (TB) to human immunodeficiency virus/acquired immunodeficiency syndrome (HIV/AIDS), the burden of TB is now difficult to manage. Therefore, new antimycobacterial agents are being sought from natural sources. This review focuses on natural antimycobacterial agents from endophytes and medicinal plants of Africa, Europe, Asia, South America and Canada. In the countries mentioned in this review, numerous plant species display putative anti-TB activity. Several antimycobacterial chemical compounds have also been isolated, including: ellagitannin punicalagin, allicin, anthraquinone glycosides, iridoids, phenylpropanoids, beta-sitosterol, galanthimine, crinine, friedelin, gallic acid, ellagic acids, anthocyanidin, taraxerol, termilignan B, arjunic acid, glucopyranosides, 1-epicatechol, leucopelargonidol, hydroxybenzoic acids, benzophenanthridine alkaloids, neolignans, and decarine. These compounds may provide leads to novel and more efficacious drugs to lessen the global burden of TB and drug-resistant M. tuberculosis strains. If there is a long-term remedy for TB, it must lie in nature's pharmacy of putative antimycobacterial agents. PMID:26464047

  19. An agent-based microsimulation of critical infrastructure systems

    SciTech Connect

    BARTON,DIANNE C.; STAMBER,KEVIN L.

    2000-03-29

    US infrastructures provide essential services that support the economic prosperity and quality of life. Today, the latest threat to these infrastructures is the increasing complexity and interconnectedness of the system. On balance, added connectivity will improve economic efficiency; however, increased coupling could also result in situations where a disturbance in an isolated infrastructure unexpectedly cascades across diverse infrastructures. An understanding of the behavior of complex systems can be critical to understanding and predicting infrastructure responses to unexpected perturbation. Sandia National Laboratories has developed an agent-based model of critical US infrastructures using time-dependent Monte Carlo methods and a genetic algorithm learning classifier system to control decision making. The model is currently under development and contains agents that represent the several areas within the interconnected infrastructures, including electric power and fuel supply. Previous work shows that agent-based simulations models have the potential to improve the accuracy of complex system forecasting and to provide new insights into the factors that are the primary drivers of emergent behaviors in interdependent systems. Simulation results can be examined both computationally and analytically, offering new ways of theorizing about the impact of perturbations to an infrastructure network.

  20. Recent developments in antiviral agents against enterovirus 71 infection

    PubMed Central

    2014-01-01

    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. PMID:24521134

  1. Pareto and Boltzmann Gibbs behaviors in a deterministic multi-agent system

    NASA Astrophysics Data System (ADS)

    González-Estévez, J.; Cosenza, M. G.; López-Ruiz, R.; Sánchez, J. R.

    2008-07-01

    A deterministic system of interacting agents is considered as a model for economic dynamics. The dynamics of the system is described by a coupled map lattice with nearest neighbor interactions. The evolution of each agent results from the competition between two factors: the agent’s own tendency to grow and the environmental influence that moderates this growth. Depending on the values of the parameters that control these factors, the system can display Pareto or Boltzmann-Gibbs statistical behaviors in its asymptotic dynamical regime. The regions where these behaviors appear are calculated on the space of parameters of the system. Other statistical properties, such as the mean wealth, the standard deviation, and the Gini coefficient characterizing the degree of equity in the wealth distribution are also calculated.

  2. THREE-DIMENSIONAL MODELING OF THE DYNAMICS OF THERAPEUTIC ULTRASOUND CONTRAST AGENTS

    PubMed Central

    Hsiao, Chao-Tsung; Lu, Xiaozhen; Chahine, Georges

    2010-01-01

    A 3-D thick-shell contrast agent dynamics model was developed by coupling a finite volume Navier-Stokes solver and a potential boundary element method flow solver to simulate the dynamics of thick-shelled contrast agents subjected to pressure waves. The 3-D model was validated using a spherical thick-shell model validated by experimental observations. We then used this model to study shell break-up during nonspherical deformations resulting from multiple contrast agent interaction or the presence of a nearby solid wall. Our simulations indicate that the thick viscous shell resists the contrast agent from forming a re-entrant jet, as normally observed for an air bubble oscillating near a solid wall. Instead, the shell thickness varies significantly from location to location during the dynamics, and this could lead to shell break-up caused by local shell thinning and stretching. PMID:20950929

  3. Quick torque coupling

    DOEpatents

    Luft, Peter A.

    2009-05-12

    A coupling for mechanically connecting modular tubular struts of a positioning apparatus or space frame, comprising a pair of toothed rings (10, 12) attached to separate strut members (16), the teeth (18, 20) of the primary rings (10, 12) mechanically interlocking in both an axial and circumferential manner, and a third part comprising a sliding, toothed collar (14) the teeth (22) of which interlock the teeth (18, 20) of the primary rings (10, 12), preventing them from disengaging, and completely locking the assembly together. A secondary mechanism provides a nesting force for the collar, and/or retains it. The coupling is self-contained and requires no external tools for installation, and can be assembled with gloved hands in demanding environments. No gauging or measured torque is required for assembly. The assembly can easily be visually inspected to determine a "go" or "no-go" status. The coupling is compact and relatively light-weight. Because of it's triply interlocking teeth, the connection is rigid. The connection does not primarily rely on clamps, springs or friction based fasteners, and is therefore reliable in fail-safe applications.

  4. Emergent Behavior of Coupled Barrier Island - Resort Systems

    NASA Astrophysics Data System (ADS)

    McNamara, D. E.; Werner, B. T.

    2004-12-01

    Barrier islands are attractive sites for resorts. Natural barrier islands experience beach erosion and island overwash during storms, beach accretion and dune building during inter-storm periods, and migration up the continental shelf as sea level rises. Beach replenishment, artificial dune building, seawalls, jetties and groins have been somewhat effective in protecting resorts against erosion and overwash during storms, but it is unknown how the coupled system will respond to long-term sea level rise. We investigate coupled barrier island - resort systems using an agent-based model with three components: natural barrier islands divided into a series of alongshore cells; resorts controlled by markets for tourism and hotel purchases; and coupling via storm damage to resorts and resort protection by government agents. Modeled barrier islands change by beach erosion, island overwash and inlet cutting during storms, and beach accretion, tidal delta growth and dune and vegetation growth between storms. In the resort hotel market, developer agents build hotels and hotel owning agents purchase them using predictions of future revenue and property appreciation, with the goal of maximizing discounted utility. In the tourism market, hotel owning agents set room rental prices to maximize profit and tourist agents choose vacation destinations maximizing a utility based on beach width, price and word-of-mouth. Government agents build seawalls, groins and jetties, and widen the beach and build up dunes by adding sand to protect resorts from storms, enhance beach quality, and maximize resort revenue. Results indicate that barrier islands and resorts evolve in a coupled manner to resort size saturation, with resorts protected against small-to-intermediate-scale storms under fairly stable sea level. Under extended, rapidly rising sea level, protection measures enhance the effect of large storms, leading to emergent behavior in the form of limit cycles or barrier submergence, depending on the relative rates of resort recovery from storms and sea level rise. The model is applied to Ocean City, Maryland and neighboring undeveloped Assateague Island National Seashore. Supported by the National Science Foundation, Geology and Paleontology Program, and the Andrew W. Mellon Foundation

  5. Serotonin Regulates Electrical Coupling via Modulation of Extrajunctional Conductance: H-current

    PubMed Central

    Szabo, Theresa M.; Caplan, Jonathan S.; Zoran, Mark J.

    2010-01-01

    Synaptic strength can be highly variable from animal to animal within a species or over time within an individual. The process of synaptic plasticity induced by neuromodulatory agents might be unpredictable when the underlying circuits subject to modulation are themselves inherently variable. Serotonin (5-hydroxytryptomine; 5HT) and serotonergic signaling pathways are important regulators of animal behavior and are pharmacological targets in a wide range of neurological disorders. We have examined the effect of 5HT on electrical synapses possessing variable coupling strengths. While 5HT decreased electrical coupling at synapses with weak electrical connectivity, synapses with strong electrical coupling were less affected by 5HT treatment, as follows from the equations used for calculating coupling coefficients. The fact that the modulatory effect of 5HT on electrical connections was negatively correlated with the strength of electrical coupling suggests that the degree of electrical coupling within a neural network impacts subsequent neuromodulation of those synapses. Biophysical studies indicated that these effects were primarily due to 5HT-induced modulation of membrane currents that indirectly affect junctional coupling at synaptic contacts. In support of these experimental analyses, we created a simple model of coupled neurons to demonstrate that modulation of electrical coupling could be due solely to 5HT effects on H-channel conductance. Therefore, variability in the strength of electrical coupling in neural circuits can determine the pharmacological effect of this neuromodulatory agent. PMID:20599836

  6. Control Architecture for Robotic Agent Command and Sensing

    NASA Technical Reports Server (NTRS)

    Huntsberger, Terrance; Aghazarian, Hrand; Estlin, Tara; Gaines, Daniel

    2008-01-01

    Control Architecture for Robotic Agent Command and Sensing (CARACaS) is a recent product of a continuing effort to develop architectures for controlling either a single autonomous robotic vehicle or multiple cooperating but otherwise autonomous robotic vehicles. CARACaS is potentially applicable to diverse robotic systems that could include aircraft, spacecraft, ground vehicles, surface water vessels, and/or underwater vessels. CARACaS incudes an integral combination of three coupled agents: a dynamic planning engine, a behavior engine, and a perception engine. The perception and dynamic planning en - gines are also coupled with a memory in the form of a world model. CARACaS is intended to satisfy the need for two major capabilities essential for proper functioning of an autonomous robotic system: a capability for deterministic reaction to unanticipated occurrences and a capability for re-planning in the face of changing goals, conditions, or resources. The behavior engine incorporates the multi-agent control architecture, called CAMPOUT, described in An Architecture for Controlling Multiple Robots (NPO-30345), NASA Tech Briefs, Vol. 28, No. 11 (November 2004), page 65. CAMPOUT is used to develop behavior-composition and -coordination mechanisms. Real-time process algebra operators are used to compose a behavior network for any given mission scenario. These operators afford a capability for producing a formally correct kernel of behaviors that guarantee predictable performance. By use of a method based on multi-objective decision theory (MODT), recommendations from multiple behaviors are combined to form a set of control actions that represents their consensus. In this approach, all behaviors contribute simultaneously to the control of the robotic system in a cooperative rather than a competitive manner. This approach guarantees a solution that is good enough with respect to resolution of complex, possibly conflicting goals within the constraints of the mission to be accomplished by the vehicle(s).

  7. Sustainable Society Formed by Unselfish Agents

    NASA Astrophysics Data System (ADS)

    Kikuchi, Toshiko

    It has been pointed out that if the social configuration of the three relations (market, communal and obligatory relations) is not balanced, a market based society as a total system fails. Using multi-agent simulations, this paper shows that a sustainable society is formed when all three relations are integrated and function respectively. When agent trades are based on the market mechanism (i.e., agents act in their own interest and thus only market relations exist), weak agents who cannot perform transactions die. If a compulsory tax is imposed to enable all weak agents to survive (i.e., obligatory relations exist), then the fiscal deficit increases. On the other hand, if agents who have excess income undertake the unselfish action of distributing their surplus to the weak agents (i.e., communal relations exist), then trade volume increases. It is shown that the existence of unselfish agents is necessary for the realization of a sustainable society. However, the survival of all agents is difficult in a communal society. In an artificial society, for all agents survive and fiscal balance to be maintained, all three social relations need to be fully integrated. These results show that adjusting the balance of the three social relations well lead to the realization of a sustainable society.

  8. Dynamic coupling of plasmonic resonators

    PubMed Central

    Lee, Suyeon; Park, Q-Han

    2016-01-01

    We clarify the nature of dynamic coupling in plasmonic resonators and determine the dynamic coupling coefficient using a simple analytic model. We show that plasmonic resonators, such as subwavelength holes in a metal film which can be treated as bound charge oscillators, couple to each other through the retarded interaction of oscillating screened charges. Our dynamic coupling model offers, for the first time, a quantitative analytic description of the fundamental symmetric and anti-symmetric modes of coupled resonators which agrees with experimental results. Our model also reveals that plasmonic electromagnetically induced transparency arises in any coupled resonators of slightly unequal lengths, as confirmed by a rigorous numerical calculation and experiments. PMID:26911786

  9. Agent Reward Shaping for Alleviating Traffic Congestion

    NASA Technical Reports Server (NTRS)

    Tumer, Kagan; Agogino, Adrian

    2006-01-01

    Traffic congestion problems provide a unique environment to study how multi-agent systems promote desired system level behavior. What is particularly interesting in this class of problems is that no individual action is intrinsically "bad" for the system but that combinations of actions among agents lead to undesirable outcomes, As a consequence, agents need to learn how to coordinate their actions with those of other agents, rather than learn a particular set of "good" actions. This problem is ubiquitous in various traffic problems, including selecting departure times for commuters, routes for airlines, and paths for data routers. In this paper we present a multi-agent approach to two traffic problems, where far each driver, an agent selects the most suitable action using reinforcement learning. The agent rewards are based on concepts from collectives and aim to provide the agents with rewards that are both easy to learn and that if learned, lead to good system level behavior. In the first problem, we study how agents learn the best departure times of drivers in a daily commuting environment and how following those departure times alleviates congestion. In the second problem, we study how agents learn to select desirable routes to improve traffic flow and minimize delays for. all drivers.. In both sets of experiments,. agents using collective-based rewards produced near optimal performance (93-96% of optimal) whereas agents using system rewards (63-68%) barely outperformed random action selection (62-64%) and agents using local rewards (48-72%) performed worse than random in some instances.

  10. The Extended Mind: Coupling Environment and Brain

    NASA Astrophysics Data System (ADS)

    Vrobel, Susie

    2010-11-01

    This paper describes embodiment and cognitive extension as examples of strong anticipation as defined by Dubois. Clark and Chalmers formulated a thesis which states that parts of the environment, if coupled successfully, can become part of the extended mind. This coupling, be it deliberate or unintentional, shifts the observer-world boundary outwards when the observer encompasses parts of his environment. The resulting extended observer forms a new systemic whole, which consists of both the assimilated context and the recalibrated version of the original observer. Recalibration occurs when conditioning and adaptation lead to corresponding changes on the neural level, for instance, when an agent compensates for delays in a control loop. Plasticity is a prerequisite for any successful incorporation of external structures. However, uncoupled parts of the observer must remain inviolate in order to preserve the boundary. Neither the extended mind nor the core observer are absolute concepts. Depending on whether we focus on local-scale interactions or on large-scale behaviour, boundaries are formed at different interfacial cuts, which lead to either an endo- or an exo-perspective or endo- or exo-anticipation, respectively. For biological extended agents which undergo a transition from exo- to endo-states, a tell-tale sign of a successful exo-endo transition is invisibility. This invisibility occurs when the agent is no longer aware of the delay originally introduced into the control loop by the assimilated part of the environment. Explaining the world in terms of effective causality is not sufficient to account for extended minds. The latter require explanations in terms of final causation. For extended minds, this ordering principle comes in the shape of nested hierarchical layers. The interfaces of these layers may have merged for an endo-observer, whereas an exo-observer can make out the detailed structure, including artificially introduced delays. A sufficient condition for an endo-observer to turn into an extended mind is the formation of a new systemic whole as a result of shifting the interfacial cut between exo-and endo-world outwards. However, this is only a necessary condition for an extended agent with strong anticipatory properties. It is invisibility which is a sufficient condition for strong or endo-anticipation.

  11. Collective Motion in a Network of Self-Propelled Agent Systems

    PubMed Central

    Peng, Hao; Zhao, Dandan; Liu, Xueming; Gao, Jianxi

    2015-01-01

    Collective motions of animals that move towards the same direction is a conspicuous feature in nature. Such groups of animals are called a self-propelled agent (SPA) systems. Many studies have been focused on the synchronization of isolated SPA systems. In real scenarios, different SPA systems are coupled with each other forming a network of SPA systems. For example, a flock of birds and a school of fish show predator-prey relationships and different groups of birds may compete for food. In this work, we propose a general framework to study the collective motion of coupled self-propelled agent systems. Especially, we study how three different connections between SPA systems: symbiosis, predator-prey, and competition influence the synchronization of the network of SPA systems. We find that a network of SPA systems coupled with symbiosis relationship arrive at a complete synchronization as all its subsystems showing a complete synchronization; a network of SPA systems coupled by predator-prey relationship can not reach a complete synchronization and its subsystems converges to different synchronized directions; and the competitive relationship between SPA systems could increase the synchronization of each SPA systems, while the network of SPA systems coupled by competitive relationships shows an optimal synchronization for small coupling strength, indicating that small competition promotes the synchronization of the entire system. PMID:26640954

  12. Antagonistic formation motion of cooperative agents

    NASA Astrophysics Data System (ADS)

    Lu, Wan-Ting; Dai, Ming-Xiang; Xue, Fang-Zheng

    2015-02-01

    This paper investigates a new formation motion problem of a class of first-order multi-agent systems with antagonistic interactions. A distributed formation control algorithm is proposed for each agent to realize the antagonistic formation motion. A sufficient condition is derived to ensure that all of the agents make an antagonistic formation motion in a distributed manner. It is shown that all of the agents can be spontaneously divided into several groups and that agents in the same group collaborate while agents in different groups compete. Finally, a numerical simulation is included to demonstrate our theoretical results. Project supported by the National Natural Science Foundation of China (Grant Nos. 61203080 and 61473051) and the Natural Science Foundation of Chongqing City (Grant No. CSTC 2011BB0081).

  13. A New Understanding of Chemical Agent Release

    SciTech Connect

    Nakafuji, G; Greenman, R; Theofanous, T

    2002-07-24

    The evolution of thickened chemical agent released at supersonic velocities, due to a missile defense intercept or a properly functioning warhead, has been misunderstood. Current and historical experimental and modeling efforts have attributed agent breakup to a variety of droplet breakup mechanisms. According to this model, drops of agent fragment into subsequent generations of smaller drops until a stable drop size is reached. Recent experimental data conducted in a supersonic wind tunnel show that agent breakup is not driven by any droplet breakup mechanism. The breakup of agent is instead governed by viscoelastic behavior and aerodynamic history effects. This viscoelastic breakup mechanism results in the formation of threads and sheets of liquid, instead of drops. The evolution and final state of agent released has broad implications not only for aerobreakup models, but also for all atmospheric dispersion models.

  14. A Highly Secure Mobile Agent System Architecture

    NASA Astrophysics Data System (ADS)

    Okataku, Yasukuni; Okutomi, Hidetoshi; Yoshioka, Nobukazu; Ohgishi, Nobuyuki; Honiden, Shinichi

    We propose a system architecture for mobile agents to improve their security in the environments of insecure networks and non-sophisticated terminals such as PDAs. As mobile agents freely migrate onto their favorite terminals through insecure networks or terminals, it is not appropriate for them to store some secret information for authentication and encryption/decryption. We introduce one and more secure nodes(OASIS NODE) for securely generating and verifying authentication codes. The each agent’s data are encrypted by a pseudo-chaos cipher mechanism which doesn’t need any floating processing co-processor. We’ve constructed a prototype system on a Java mobile agent framework, “Bee-gent" which implements the proposed authentication and cipher mechanisms, and evaluated their performances and their applicability to business fields such as an auction system by mobile agents.

  15. Multi-Agent Information Classification Using Dynamic Acquaintance Lists.

    ERIC Educational Resources Information Center

    Mukhopadhyay, Snehasis; Peng, Shengquan; Raje, Rajeev; Palakal, Mathew; Mostafa, Javed

    2003-01-01

    Discussion of automated information services focuses on information classification and collaborative agents, i.e. intelligent computer programs. Highlights include multi-agent systems; distributed artificial intelligence; thesauri; document representation and classification; agent modeling; acquaintances, or remote agents discovered through…

  16. Multi-Agent Information Classification Using Dynamic Acquaintance Lists.

    ERIC Educational Resources Information Center

    Mukhopadhyay, Snehasis; Peng, Shengquan; Raje, Rajeev; Palakal, Mathew; Mostafa, Javed

    2003-01-01

    Discussion of automated information services focuses on information classification and collaborative agents, i.e. intelligent computer programs. Highlights include multi-agent systems; distributed artificial intelligence; thesauri; document representation and classification; agent modeling; acquaintances, or remote agents discovered through…

  17. Massive Multi-Agent Systems Control

    NASA Technical Reports Server (NTRS)

    Campagne, Jean-Charles; Gardon, Alain; Collomb, Etienne; Nishida, Toyoaki

    2004-01-01

    In order to build massive multi-agent systems, considered as complex and dynamic systems, one needs a method to analyze and control the system. We suggest an approach using morphology to represent and control the state of large organizations composed of a great number of light software agents. Morphology is understood as representing the state of the multi-agent system as shapes in an abstract geometrical space, this notion is close to the notion of phase space in physics.

  18. Biological and chemical agents: a brief synopsis.

    PubMed

    Rosenbloom, Mark; Leikin, Jerrold B; Vogel, Stephen N; Chaudry, Zafar A

    2002-01-01

    The objective of this article is to provide a concise overview of the most likely biological and chemical agents that could be used as biochemical weapons. The diagnosis, pathology, prevention, decontamination, treatment, and disposition of these biological and chemical agents are presented in a tabular format for quick reference purposes. The information provided outlines the bare essentials needed to deal with any emergency or catastrophic event involving these agents. PMID:11782813

  19. The EO-1 Autonomous Science Agent Architecture

    NASA Technical Reports Server (NTRS)

    Chien, Steve; Sherwood, Rob; Tran, Daniel; Cichy, Benjamin; Rabideau, Gregg; Castano, Rebecca; Davies, Ashley; Lee, Rachel; Mandl, Dan; Frye, Stuart; Trout, Bruce; Hengemihle, Jerry; D'Agostino, Jeff; Shulman, Seth; Ungar, Stephen; Brakke, Thomas; Boyer, Darrell; Van Gaasbeck, Jim; Greeley, Ronald; Doggett, Thomas; Baker, Victor; Dohm, James; Ip, Felipe

    2004-01-01

    An Autonomous Science Agent is currently flying onboard the Earth Observing One Spacecraft. This software enables the spacecraft to autonomously detect and respond to science events occurring on the Earth. The package includes software systems that perform science data analysis, deliberative planning, and run-time robust execution. Because of the deployment to a remote spacecraft, this Autonomous Science Agent has stringent constraints of autonomy, reliability, and limited computing resources. We describe these constraints and how they are reflected in our agent architecture.

  20. Considerations in detecting CDC select agents under field conditions

    NASA Astrophysics Data System (ADS)

    Spinelli, Charles; Soelberg, Scott; Swanson, Nathaneal; Furlong, Clement; Baker, Paul

    2008-04-01

    Surface Plasmon Resonance (SPR) has become a widely accepted technique for real-time detection of interactions between receptor molecules and ligands. Antibody may serve as receptor and can be attached to the gold surface of the SPR device, while candidate analyte fluids contact the detecting antibody. Minute, but detectable, changes in refractive indices (RI) indicate that analyte has bound to the antibody. A decade ago, an inexpensive, robust, miniature and fully integrated SPR chip, called SPREETA, was developed. University of Washington (UW) researchers subsequently developed a portable, temperature-regulated instrument, called SPIRIT, to simultaneously use eight of these three-channel SPREETA chips. A SPIRIT prototype instrument was tested in the field, coupled to a remote reporting system on a surrogate unmanned aerial vehicle (UAV). Two target protein analytes were released sequentially as aerosols with low analyte concentration during each of three flights and were successfully detected and verified. Laboratory experimentation with a more advanced SPIRIT instrument demonstrated detection of very low levels of several select biological agents that might be employed by bioterrorists. Agent detection under field-like conditions is more challenging, especially as analyte concentrations are reduced and complex matricies are introduced. Two different sample preconditioning protocols have been developed for select agents in complex matrices. Use of these preconditioning techniques has allowed laboratory detection in spiked heavy mud of Francisella tularensis at 10 3 CFU/ml, Bacillus anthracis spores at 10 3 CFU/ml, Staphylococcal enterotoxin B (SEB) at 1 ng/ml, and Vaccinia virus (a smallpox simulant) at 10 5 PFU/ml. Ongoing experiments are aimed at simultaneous detection of multiple agents in spiked heavy mud, using a multiplex preconditioning protocol.

  1. Moving Just Like You: Motor Interference Depends on Similar Motility of Agent and Observer

    PubMed Central

    Kupferberg, Aleksandra; Huber, Markus; Helfer, Bartosz; Lenz, Claus; Knoll, Alois; Glasauer, Stefan

    2012-01-01

    Recent findings in neuroscience suggest an overlap between brain regions involved in the execution of movement and perception of another’s movement. This so-called “action-perception coupling” is supposed to serve our ability to automatically infer the goals and intentions of others by internal simulation of their actions. A consequence of this coupling is motor interference (MI), the effect of movement observation on the trajectory of one’s own movement. Previous studies emphasized that various features of the observed agent determine the degree of MI, but could not clarify how human-like an agent has to be for its movements to elicit MI and, more importantly, what ‘human-like’ means in the context of MI. Thus, we investigated in several experiments how different aspects of appearance and motility of the observed agent influence motor interference (MI). Participants performed arm movements in horizontal and vertical directions while observing videos of a human, a humanoid robot, or an industrial robot arm with either artificial (industrial) or human-like joint configurations. Our results show that, given a human-like joint configuration, MI was elicited by observing arm movements of both humanoid and industrial robots. However, if the joint configuration of the robot did not resemble that of the human arm, MI could longer be demonstrated. Our findings present evidence for the importance of human-like joint configuration rather than other human-like features for perception-action coupling when observing inanimate agents. PMID:22761853

  2. Air-Coupled Vibrometry

    NASA Astrophysics Data System (ADS)

    Döring, D.; Solodov, I.; Busse, G.

    Sound and ultrasound in air are the products of a multitude of different processes and thus can be favorable or undesirable phenomena. Development of experimental tools for non-invasive measurements and imaging of airborne sound fields is of importance for linear and nonlinear nondestructive material testing as well as noise control in industrial or civil engineering applications. One possible solution is based on acousto-optic interaction, like light diffraction imaging. The diffraction approach usually requires a sophisticated setup with fine optical alignment barely applicable in industrial environment. This paper focuses on the application of the robust experimental tool of scanning laser vibrometry, which utilizes commercial off-the-shelf equipment. The imaging technique of air-coupled vibrometry (ACV) is based on the modulation of the optical path length by the acoustic pressure of the sound wave. The theoretical considerations focus on the analysis of acousto-optical phase modulation. The sensitivity of the ACV in detecting vibration velocity was estimated as ~1 mm/s. The ACV applications to imaging of linear airborne fields are demonstrated for leaky wave propagation and measurements of ultrasonic air-coupled transducers. For higher-intensity ultrasound, the classical nonlinear effect of the second harmonic generation was measured in air. Another nonlinear application includes a direct observation of the nonlinear air-coupled emission (NACE) from the damaged areas in solid materials. The source of the NACE is shown to be strongly localized around the damage and proposed as a nonlinear "tag" to discern and image the defects.

  3. Controllable optomechanical coupling in serially-coupled triple resonators

    SciTech Connect

    Huang, Chenguang Zhao, Yunsong; Fan, Jiahua; Zhu, Lin

    2014-12-15

    Radiation pressure can efficiently couple mechanical modes with optical modes in an optical cavity. The coupling efficiency is quite dependent on the interaction between the optical mode and mechanical mode. In this report, we investigate a serially-coupled triple resonator system, where a freestanding beam is placed in the vicinity of the middle resonator. In this coupled system, we demonstrate that the mechanical mode of the free-standing beam can be selectively coupled to different resonance supermodes through the near field interaction.

  4. Sealing coupling. [LMFBR

    DOEpatents

    Pardini, J.A.; Brubaker, R.C.; Rusnak, J.J.

    1982-09-20

    Disclosed is a remotely operable releasable sealing coupling which provides fluid-tight joinder of upper and a lower conduit sections. Each conduit section has a concave conical sealing surface adjacent its end portion. A tubular sleeve having convex spherical ends is inserted between the conduit ends to form line contact with the concave conical end portions. An inwardly projecting lip located at one end of the sleeve cooperates with a retaining collar formed on the upper pipe end to provide swivel capture for the sleeve. The upper conduit section also includes a tapered lower end portion which engages the inside surface of the sleeve to limit misalignment of the connected conduit sections.

  5. Characterization of chemical agent transport in paints.

    PubMed

    Willis, Matthew P; Gordon, Wesley; Lalain, Teri; Mantooth, Brent

    2013-09-15

    A combination of vacuum-based vapor emission measurements with a mass transport model was employed to determine the interaction of chemical warfare agents with various materials, including transport parameters of agents in paints. Accurate determination of mass transport parameters enables the simulation of the chemical agent distribution in a material for decontaminant performance modeling. The evaluation was performed with the chemical warfare agents bis(2-chloroethyl) sulfide (distilled mustard, known as the chemical warfare blister agent HD) and O-ethyl S-[2-(diisopropylamino)ethyl] methylphosphonothioate (VX), an organophosphate nerve agent, deposited on to two different types of polyurethane paint coatings. The results demonstrated alignment between the experimentally measured vapor emission flux and the predicted vapor flux. Mass transport modeling demonstrated rapid transport of VX into the coatings; VX penetrated through the aliphatic polyurethane-based coating (100 μm) within approximately 107 min. By comparison, while HD was more soluble in the coatings, the penetration depth in the coatings was approximately 2× lower than VX. Applications of mass transport parameters include the ability to predict agent uptake, and subsequent long-term vapor emission or contact transfer where the agent could present exposure risks. Additionally, these parameters and model enable the ability to perform decontamination modeling to predict how decontaminants remove agent from these materials. PMID:23872337

  6. Conversational Agents in E-Learning

    NASA Astrophysics Data System (ADS)

    Kerry, Alice; Ellis, Richard; Bull, Susan

    This paper discusses the use of natural language or 'conversational' agents in e-learning environments. We describe and contrast the various applications of conversational agent technology represented in the e-learning literature, including tutors, learning companions, language practice and systems to encourage reflection. We offer two more detailed examples of conversational agents, one which provides learning support, and the other support for self-assessment. Issues and challenges for developers of conversational agent systems for e-learning are identified and discussed.

  7. 7 CFR 906.59 - Agents.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... ORDERS; FRUITS, VEGETABLES, NUTS), DEPARTMENT OF AGRICULTURE ORANGES AND GRAPEFRUIT GROWN IN LOWER RIO GRANDE VALLEY IN TEXAS Order Regulating Handling Miscellaneous Provisions § 906.59 Agents. The...

  8. 7 CFR 906.59 - Agents.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... ORDERS; FRUITS, VEGETABLES, NUTS), DEPARTMENT OF AGRICULTURE ORANGES AND GRAPEFRUIT GROWN IN LOWER RIO GRANDE VALLEY IN TEXAS Order Regulating Handling Miscellaneous Provisions § 906.59 Agents. The...

  9. 7 CFR 906.59 - Agents.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... Orders; Fruits, Vegetables, Nuts), DEPARTMENT OF AGRICULTURE ORANGES AND GRAPEFRUIT GROWN IN LOWER RIO GRANDE VALLEY IN TEXAS Order Regulating Handling Miscellaneous Provisions § 906.59 Agents. The...

  10. 7 CFR 906.59 - Agents.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... Orders; Fruits, Vegetables, Nuts), DEPARTMENT OF AGRICULTURE ORANGES AND GRAPEFRUIT GROWN IN LOWER RIO GRANDE VALLEY IN TEXAS Order Regulating Handling Miscellaneous Provisions § 906.59 Agents. The...

  11. Oak Ridge Mobile Agent Community (ORMAC)

    Energy Science and Technology Software Center (ESTSC)

    2003-06-30

    The Oak Ridge Mobile Agent Community (ORMAC) framework software facilitates the execution of a collection of mobile software agents across a heterogeneous collection of computer systems. ORMAC provides the software agents with the ability to communicate with each other in a synchronous and asynchronous manner. Also, ORMAC allows the software agents to move to any computer system in the community and continue execution there. ORMAC is intended to aid programmers in solving a very generalmore » set of distributed software problems.« less

  12. Agent-Based Negotiation in Uncertain Environments

    NASA Astrophysics Data System (ADS)

    Debenham, John; Sierra, Carles

    An agent aims to secure his projected needs by attempting to build a set of (business) relationships with other agents. A relationship is built by exchanging private information, and is characterised by its intimacy — degree of closeness — and balance — degree of fairness. Each argumentative interaction between two agents then has two goals: to satisfy some immediate need, and to do so in a way that develops the relationship in a desired direction. An agent's desire to develop each relationship in a particular way then places constraints on the argumentative utterances. The form of negotiation described is argumentative interaction constrained by a desire to develop such relationships.

  13. Agents in bioinformatics, computational and systems biology.

    PubMed

    Merelli, Emanuela; Armano, Giuliano; Cannata, Nicola; Corradini, Flavio; d'Inverno, Mark; Doms, Andreas; Lord, Phillip; Martin, Andrew; Milanesi, Luciano; Möller, Steffen; Schroeder, Michael; Luck, Michael

    2007-01-01

    The adoption of agent technologies and multi-agent systems constitutes an emerging area in bioinformatics. In this article, we report on the activity of the Working Group on Agents in Bioinformatics (BIOAGENTS) founded during the first AgentLink III Technical Forum meeting on the 2nd of July, 2004, in Rome. The meeting provided an opportunity for seeding collaborations between the agent and bioinformatics communities to develop a different (agent-based) approach of computational frameworks both for data analysis and management in bioinformatics and for systems modelling and simulation in computational and systems biology. The collaborations gave rise to applications and integrated tools that we summarize and discuss in context of the state of the art in this area. We investigate on future challenges and argue that the field should still be explored from many perspectives ranging from bio-conceptual languages for agent-based simulation, to the definition of bio-ontology-based declarative languages to be used by information agents, and to the adoption of agents for computational grids. PMID:16772270

  14. Preventing transfer of infectious agents.

    PubMed

    Denner, Joachim; Mueller, Nicolas J

    2015-11-01

    Xenotransplantation using pig cells, tissues and organs may be associated with the transfer of porcine infectious agents, which may infect the human recipient and in the worst case induce a disease (zoonosis). To prevent this, a broad screening program of the donor animals for putative zoonotic microorganisms, including bacteria, viruses, fungi and others, using sensitive and specific detection methods has to be performed. As long as it is still unknown, which microorganism represents a real risk for the recipient, experience from allotransplantation should be brought in. Due to the fact that pigs can be screened long before the date of transplantation, xenotransplantation will become eventually safer compared with allotransplantation. Screening and selection of animals free of potential zoonotic microorganisms, Caesarean section, vaccination and/or treatment with chemotherapeutics are the strategies of choice to obtain donor animals not transmitting microorganisms. In the case of porcine endogenous retroviruses (PERVs) which are integrated in the genome of all pigs and which cannot be eliminated this way, selection of animals with low virus expression and generation of genetically modified pigs suppressing PERV expressions may be performed. PMID:26316157

  15. Direct anti-HCV agents

    PubMed Central

    Zhang, Xingquan

    2015-01-01

    Unlike human immunodeficiency virus (HIV) and hepatitis B virus (HBV), hepatitis C virus (HCV) infection is a curable disease. Current direct antiviral agent (DAA) targets are focused on HCV NS3/4A protein (protease), NS5B protein (polymerase) and NS5A protein. The first generation of DAAs includes boceprevir and telaprevir, which are protease inhibitors and were approved for clinical use in 2011. The cure rate for genotype 1 patients increased from 45% to 70% when boceprevir or telaprevir was added to standard PEG-IFN/ribavirin. More effective and less toxic second generation DAAs supplanted these drugs by 2013. The second generation of DAAs includes sofosbuvir (Sovaldi), simeprevir (Olysio), and fixed combination medicines Harvoni and Viekira Pak. These drugs increase cure rates to over 90% without the need for interferon and effectively treat all HCV genotypes. With these drugs the “cure HCV” goal has become a reality. Concerns remain about drug resistance mutations and the high cost of these drugs. The investigation of new HCV drugs is progressing rapidly; fixed dose combination medicines in phase III clinical trials include Viekirax, asunaprevir+daclatasvir+beclabuvir, grazoprevir+elbasvir and others. PMID:26904396

  16. Departments as Agents of Change

    NASA Astrophysics Data System (ADS)

    Lagowski, J. J.

    1996-07-01

    Higher education is changing because it has no choice. And, for the most part, outside influences are dictating the processes of change. The more fortunate institutions have had a flat budget during this period, but most have been forced to deal with a declining revenue stream as well. Legislators seem bent on micromanaging state-supported institutions, even as they cut their support. Regulators demand greater institutional accountability. Students and their parents expect more service at lower prices and increased flexibility. Technological advances have dramatically affected the availability and accessibility of extant knowledge. It is no longer a question of whether institutions will change, but rather, who will control the change. Most institutions possess long-standing academic traditions, but these are placed at risk in an increasingly competitive market that holds little sympathy for such traditions and may even see them as obstacles or barriers. As a result, the change agents will undoubtedly have a profound effect on the very nature of academic institutions. From the academic point of view, it would seem prudent to attempt to manage the changes that will inevitably occur. A number of concerned observers, notably the Pew Higher Education Roundtable and the American Association for Higher Education, argue persuasively that the academic department is the logical focus for responding to the current winds of change. Using a marketing metaphor, the academic department has been likened to a "producers' cooperative" of services that consumers seek. Thus, the department should be held accountable for the quality of teaching delivered by its members, for the coherence of its major, for its contributions to the general education curriculum, and for supervising and rewarding its individual faculty members. If departments are to be held accountable, it is surely in their best interest to act in such a way that they are accountable. Expecting academic departments to be the principal agents for recasting American higher education might appear to some like putting a fox in charge of the chicken coop. For many observers, departments epitomize everything that is wrong with higher education. Departments have come to be viewed as the agents of a discipline that draw faculty attention away from their home institution, and seek to sustain individual privilege at the expense of initiatives designed to enhance learning and teaching. Departments have been portrayed as clans of arrogant experts accountable only to their own personal agendas and to their disciplines. From this rather harsh point of view, departments have become privatized as they and their institutions strive to enhance their reputations through the faculty they hire, often at the expense of undergraduate teaching. Faculty define their interests in increasingly narrow terms, which in turn is often reflected in the courses they teach. As individual courses come to represent the increasingly specialized views of their faculty-owners, the curriculum begins to lose focus and coherence. Thus, the privatization of faculty effort has far-reaching effects on an institution's educational mission. In spite of its apparent flaws, the department, more than any other unit, stands the best chance of providing the basis of change that can renew higher education. Although individual faculty members may find their greatest rewards elsewhere, a department can only be rewarded on the basis of the combined efforts and accomplishments of its collective faculty. This fact alone makes departments an obvious vehicle for change. Furthermore, institutional support for a discipline is focused in the department, as is the institution's responsibility for teaching undergraduates. For a department to compete effectively in the new marketplace, it must ensure that its members remain active scholars who are not only expert in their primary fields, but also open to inter- and cross-disciplinary opportunities. New developments and intellectual opportunities will continue to occur at the interfaces between traditional disciplines and must be expressed to students. These are the very processes whereby disciplines themselves evolve and change. An effective department will hold its members accountable for the quality of learning achieved by both its majors and students seeking general knowledge. In this regard, the department is the logical arena for faculty to talk regularly about how, what, and why they teach, as well as to learn from each other and from their students as they strive to lay a solid intellectual foundation while keeping course content current and relevant and to interpret the meaning of success in an increasingly competitive marketplace for ideas, jobs, and opportunities. An effective department will function as a team of scholars with diverse experiences, talents, interests, and ambitions that is willing to assign (and reward) different responsibilities to individual members at different stages of their professional careers. If the renewal of undergraduate education is to occur through the department, a department must become an agent of the institution as well as of its discipline. Methods must be devised to foster greater commitment to teamwork. Rewards at the faculty and departmental level must be restructured to respond to the collective achievement of the department in both teaching and research. Techniques need to be developed to make effective teaching a subject of collective dialogue and inquiry and a mutually shared goal. Teaching should become the focus of the kind of scholarly activity that most faculty now reserve for their disciplines. Effective systems of quality control must be devised by institutions as well as mechanisms for rewarding departments that attain collective goals. Up to now, most departments and their faculties have been reluctant to engage in the kind of self-scrutiny that is the hallmark of successful service-oriented enterprises. Using the marketing metaphor again, an organization that focuses on its customers will tailor its services to fit their needs, continually monitor its success in fulfilling service goals, and make adjustments over time. Approached with a positive attitude, this is a time of exciting opportunities for departments and their faculties. JJL

  17. Fast ignitor coupling physics

    SciTech Connect

    Mason, R.J.; Tabak, M.

    1997-10-01

    The Fast Ignitor is an alternate approach to ICF in which short pulse lasers are used to initiate burn at the surface of the compressed DT fuel. The aim is to avoid the need for careful central focusing of final shocks, and possibly to lower substantially the energy requirements for ignition. Ultimately, both goals may prove crucial to Science Based Stockpile Stewardship (SBSS). This will be the case should either emerging energetic needs, or funding difficulties render the presently planned radiative fusion approach to ignition with the NIF impractical. Ignition is a first step towards the achievement of substantial energy and neutron outputs for such Stewardship. For success with the Fast Ignitor, the laser energy must be efficiently deposited into megavolt electrons (suprathermal), which must, in turn, couple to the background ions within an alpha particle range. To understand the electron fuel coupling, we have used ANTHEM plasma simulation code to model the transport of hot electrons generated by an intense short pulse laser into plasma targets over a broad range of densities. Our study will spell out the acceleration and transport mechanisms active in the Fast Ignitor environment.

  18. Fast ignitor coupling physics

    SciTech Connect

    Mason, R.J.; Tabak, M.

    1997-10-01

    The Fast Ignitor is an alternate approach to ICF in which short pulse lasers are used to initiate burn at the surface of the compressed DT fuel. The aim is to avoid the need for careful central focussing of final shocks, and possibly to lower substantially the energy requirements for ignition. Ultimately, both goals may prove crucial to Stockpile Stewardship. For success with the Fast Ignitor, the laser energy must be efficiently deposited into megavolt electrons, which must, in turn, couple to the background ions within an alpha particle range. To understand this coupling, we have used ANTHEM plasma simulation code to model the transport of hot electrons generated by an intense ({ge} 3 x 10{sup 18} W/cm{sup 2}) short pulse 1.06 {mu}m laser into plasma targets over a broad range of densities (0.35 to 10{sup 4} x n{sub crit}). Ponderomotive effects are included as a force on the cold background and hot emission electrons of the form, F{sub h,c} = -({omega}{sup 2}{sub Ph,c}/2{omega}{sup 2}){del}I, in which I is the laser intensity and {omega}{sub p}{sup 2} = 4{pi}e{sup 2}n/m{sub 0}{gamma} with m{sub 0} the electron rest mass.

  19. Multiphysics Application Coupling Toolkit

    Energy Science and Technology Software Center (ESTSC)

    2013-12-02

    This particular consortium implementation of the software integration infrastructure will, in large part, refactor portions of the Rocstar multiphysics infrastructure. Development of this infrastructure originated at the University of Illinois DOE ASCI Center for Simulation of Advanced Rockets (CSAR) to support the center's massively parallel multiphysics simulation application, Rocstar, and has continued at IllinoisRocstar, a small company formed near the end of the University-based program. IllinoisRocstar is now licensing these new developments as free, openmore » source, in hopes to help improve their own and others' access to infrastructure which can be readily utilized in developing coupled or composite software systems; with particular attention to more rapid production and utilization of multiphysics applications in the HPC environment. There are two major pieces to the consortium implementation, the Application Component Toolkit (ACT), and the Multiphysics Application Coupling Toolkit (MPACT). The current development focus is the ACT, which is (will be) the substrate for MPACT. The ACT itself is built up from the components described in the technical approach. In particular, the ACT has the following major components: 1.The Component Object Manager (COM): The COM package provides encapsulation of user applications, and their data. COM also provides the inter-component function call mechanism. 2.The System Integration Manager (SIM): The SIM package provides constructs and mechanisms for orchestrating composite systems of multiply integrated pieces.« less

  20. Multiphysics Application Coupling Toolkit

    SciTech Connect

    2013-12-02

    This particular consortium implementation of the software integration infrastructure will, in large part, refactor portions of the Rocstar multiphysics infrastructure. Development of this infrastructure originated at the University of Illinois DOE ASCI Center for Simulation of Advanced Rockets (CSAR) to support the center's massively parallel multiphysics simulation application, Rocstar, and has continued at IllinoisRocstar, a small company formed near the end of the University-based program. IllinoisRocstar is now licensing these new developments as free, open source, in hopes to help improve their own and others' access to infrastructure which can be readily utilized in developing coupled or composite software systems; with particular attention to more rapid production and utilization of multiphysics applications in the HPC environment. There are two major pieces to the consortium implementation, the Application Component Toolkit (ACT), and the Multiphysics Application Coupling Toolkit (MPACT). The current development focus is the ACT, which is (will be) the substrate for MPACT. The ACT itself is built up from the components described in the technical approach. In particular, the ACT has the following major components: 1.The Component Object Manager (COM): The COM package provides encapsulation of user applications, and their data. COM also provides the inter-component function call mechanism. 2.The System Integration Manager (SIM): The SIM package provides constructs and mechanisms for orchestrating composite systems of multiply integrated pieces.

  1. Coupled biopolymer networks

    NASA Astrophysics Data System (ADS)

    Schwarz, J. M.; Zhang, Tao

    2015-03-01

    The actin cytoskeleton provides the cell with structural integrity and allows it to change shape to crawl along a surface, for example. The actin cytoskeleton can be modeled as a semiflexible biopolymer network that modifies its morphology in response to both external and internal stimuli. Just inside the inner nuclear membrane of a cell exists a network of filamentous lamin that presumably protects the heart of the cell nucleus--the DNA. Lamins are intermediate filaments that can also be modeled as semiflexible biopolymers. It turns out that the actin cytoskeletal biopolymer network and the lamin biopolymer network are coupled via a sequence of proteins that bridge the outer and inner nuclear membranes. We, therefore, probe the consequences of such a coupling via numerical simulations to understand the resulting deformations in the lamin network in response to perturbations in the cytoskeletal network. Such study could have implications for mechanical mechanisms of the regulation of transcription, since DNA--yet another semiflexible polymer--contains lamin-binding domains, and, thus, widen the field of epigenetics.

  2. Spin-axion coupling

    NASA Astrophysics Data System (ADS)

    Balakin, Alexander B.; Popov, Vladimir A.

    2015-11-01

    We establish a new covariant phenomenological model, which describes an influence of pseudoscalar (axion) field on spins of test massive particles. The model includes general relativistic equations of particle motion and spin evolution in background pseudoscalar (axion), electromagnetic and gravitational fields. It describes both the direct spin-axion coupling of the gradient type and indirect spin-axion interaction mediated by electromagnetic fields. Special attention is paid to the direct spin-axion coupling caused by the gradient of the pseudoscalar (axion) field. We show that it describes a spin precession, when the pseudoscalar (axion) field is inhomogeneous and/or nonstationary. Applications of the model, which correspond to the three types of four-vectors attributed to the gradient of the pseudoscalar (axion) field (timelike, spacelike, and null), are considered in detail. These are the spin precessions induced by relic cosmological axions, axions distributed around spherically symmetric static objects, and axions in a gravitational wave field, respectively. We discuss features of the obtained exact solutions and some general properties of the axionically induced spin rotation.

  3. Sucker rod coupling

    SciTech Connect

    Klyne, A.A.

    1986-11-11

    An anti-friction sucker rod coupling is described for connecting a pair of sucker rods and centralizing them in a tubing string, comprising: an elongate, rigid, substantially cylindrical body member, each end of the body member forming means for threadably connecting the body member with a sucker rod. The body member further forms a transversely extending, substantially diametric, generally vertical slot extending therethrough. The body member further forms a pin bore, such pin bore extending transversely through the body member so as to intersect the slot substantially perpendicularly; a wheel member positioned within the slot to rotate in a generally vertical plane. The wheel member has a portion thereof extending beyond the periphery of the body member to engage the inner surface of the tubing string and centralize the coupling; and a pin mounted in the pin bore and supporting member thereon, whereby the wheel member is rotatable within the slot; the wheel member having sufficient clearance between its side surfaces and the wall surfaces of the slot, when the wheel member is centered in the slot on the pin, whereby the wheel member may shift along the pin to assist in ejecting sand and oil from the slot.

  4. Collective motion patterns of swarms with delay coupling: Theory and experiment

    NASA Astrophysics Data System (ADS)

    Szwaykowska, Klementyna; Schwartz, Ira B.; Mier-y-Teran Romero, Luis; Heckman, Christoffer R.; Mox, Dan; Hsieh, M. Ani

    2016-03-01

    The formation of coherent patterns in swarms of interacting self-propelled autonomous agents is a subject of great interest in a wide range of application areas, ranging from engineering and physics to biology. In this paper, we model and experimentally realize a mixed-reality large-scale swarm of delay-coupled agents. The coupling term is modeled as a delayed communication relay of position. Our analyses, assuming agents communicating over an Erdös-Renyi network, demonstrate the existence of stable coherent patterns that can be achieved only with delay coupling and that are robust to decreasing network connectivity and heterogeneity in agent dynamics. We also show how the bifurcation structure for emergence of different patterns changes with heterogeneity in agent acceleration capabilities and limited connectivity in the network as a function of coupling strength and delay. Our results are verified through simulation as well as preliminary experimental results of delay-induced pattern formation in a mixed-reality swarm.

  5. Your company's secret change agents.

    PubMed

    Pascale, Richard Tanner; Sternin, Jerry

    2005-05-01

    Organizational change has traditionally come about through top-down initiatives such as hiring experts or importing best-of-breed practices. Such methods usually result in companywide rollouts of templates mandated from on high. These do little to get people excited. But within every organization, there are a few individuals who find unique ways to look at problems that seem impossible to solve. Although these change agents start out with the same tools and access to resources as their peers, they are able to see solutions where others do not. They find a way to bridge the divide between what is happening and what is possible. These positive deviants are the key, the authors believe, to a better way of creating organizational change. Your company can make the most of their methods by following six steps. In Step 1, Make the group the guru, the members of the community are engaged in the process of their own evolution. Step 2, Reframe through facts, entails restating the problem in a way that opens minds to new possibilities. Step 3, Make it safe to learn, involves creating an environment that supports innovative ideas. In Step 4, Make the problem concrete, the community combats abstraction by stating uncomfortable truths. In Step 5, Leverage social proof, the community looks to the larger society for examples of solutions that have worked in parallel situations. In Step 6, Confound the immune defense response, solutions are introduced organically from within the group in a way that promotes acceptance. Throughout the steps, the leader must suspend his or her traditional role in favor of more facilitatory practices. The positive-deviance approach has unearthed solutions to such complicated and diverse problems as malnutrition in Mali and human trafficking in East Java. This methodology can help solve even the most extreme dilemmas. PMID:15929405

  6. High char yield epoxy curing agents

    NASA Technical Reports Server (NTRS)

    Delvigs, P.; Serafini, T. T.; Vanucci, R. D.

    1981-01-01

    Class of imide-amine curing agents preserves structural integrity, prevents fiber release, and is fully compatible with conventional epoxy resins; agents do not detract from composite properties while greatly reducing char yield. Materials utilizing curing are used in aerospace, automotive, and other structural components where deterioration must be minimized and fiber release avoided in event of fire.

  7. Biologic agents for IBD: practical insights.

    PubMed

    Danese, Silvio; Vuitton, Lucine; Peyrin-Biroulet, Laurent

    2015-09-01

    Six biologic agents are currently approved for the treatment of IBD: four anti-TNF agents (infliximab, adalimumab, golimumab and certolizumab pegol) and two anti-integrin agents (natalizumab and vedolizumab). In Crohn's disease and ulcerative colitis refractory to standard medications, treatment choice among available biologic agents can be challenging. Several parameters should be taken into account to help physicians through the decision-making process, including the comparative effectiveness and long-term safety profile, availability and labelling in the prescriber's country, international guidelines, and cost, as well as patient preferences (such as the route of administration). Herein, we provide practical insights on the use of biologic agents in IBD. The results of head-to-head trials between biologic agents are eagerly awaited to guide decision-making regarding the choice of first-line biologic agents and to determine whether switching within the same drug class or swapping (switching out of the drug class) is preferable after primary or secondary loss of response to the first biologic agent. In the near future, treatment algorithms might evolve with the launch of new drugs (such as ustekinumab, tofacitinib and etrolizumab) and the increased use of biosimilars. PMID:26284562

  8. Security of Mobile Agents on the Internet.

    ERIC Educational Resources Information Center

    Corradi, Antonio; Montanari, Rebecca; Stefanelli, Cesare

    2001-01-01

    Discussion of the Internet focuses on new programming paradigms based on mobile agents. Considers the security issues associated with mobile agents and proposes a security architecture composed of a wide set of services and components capable of adapting to a variety of applications, particularly electronic commerce. (Author/LRW)

  9. VIRAL GASTROENTERITIS AGENTS AND WATERBORNE DISEASE

    EPA Science Inventory

    The application of electron microscopic techniques in the study of human gastroenteritis led in the 1970's to the identification of new viral agents that had previously escaped detection by routine cell culture procedures. These agents have been the focus of study by researchers ...

  10. Improving Disability Awareness among Extension Agents

    ERIC Educational Resources Information Center

    Mahadevan, Lakshmi; Peterson, Rick L.; Grenwelge, Cheryl

    2014-01-01

    Increasing prevalence rates and legislative mandates imply that educators, parents, and Extension agents will need better tools and resources to meet the needs of special populations. The Texas A&M AgriLife Extension Service addresses this issue by using e-learning tools. Extension agents can take advantage of these courses to gain critical…

  11. 46 CFR 153.1106 - Cleaning agents.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 5 2010-10-01 2010-10-01 false Cleaning agents. 153.1106 Section 153.1106 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) CERTAIN BULK DANGEROUS CARGOES SHIPS CARRYING... Handling of Categories A, B, C, and D Cargo and Nls Residue § 153.1106 Cleaning agents. No tank...

  12. The Design of Motivational Agents and Avatars

    ERIC Educational Resources Information Center

    Baylor, Amy L.

    2011-01-01

    While the addition of an anthropomorphic interface agent to a learning system generally has little direct impact on learning, it potentially has a huge impact on learner motivation. As such agents become increasingly ubiquitous on the Internet, in virtual worlds, and as interfaces for learning and gaming systems, it is important to design them to…

  13. The Design of Motivational Agents and Avatars

    ERIC Educational Resources Information Center

    Baylor, Amy L.

    2011-01-01

    While the addition of an anthropomorphic interface agent to a learning system generally has little direct impact on learning, it potentially has a huge impact on learner motivation. As such agents become increasingly ubiquitous on the Internet, in virtual worlds, and as interfaces for learning and gaming systems, it is important to design them to…

  14. Improving Disability Awareness among Extension Agents

    ERIC Educational Resources Information Center

    Mahadevan, Lakshmi; Peterson, Rick L.; Grenwelge, Cheryl

    2014-01-01

    Increasing prevalence rates and legislative mandates imply that educators, parents, and Extension agents will need better tools and resources to meet the needs of special populations. The Texas A&M AgriLife Extension Service addresses this issue by using e-learning tools. Extension agents can take advantage of these courses to gain critical…

  15. 21 CFR 181.28 - Release agents.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 3 2011-04-01 2011-04-01 false Release agents. 181.28 Section 181.28 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN CONSUMPTION (CONTINUED) PRIOR-SANCTIONED FOOD INGREDIENTS Specific Prior-Sanctioned Food Ingredients § 181.28 Release agents. Substances classified...

  16. Safe motion planning for mobile agents: A model of reactive planning for multiple mobile agents

    SciTech Connect

    Fujimura, Kikuo.

    1990-01-01

    The problem of motion planning for multiple mobile agents is studied. Each planning agent independently plans its own action based on its map which contains a limited information about the environment. In an environment where more than one mobile agent interacts, the motions of the robots are uncertain and dynamic. A model for reactive agents is described and simulation results are presented to show their behavior patterns. 18 refs., 2 figs.

  17. EFFECT OF SILANE COUPLING AGENTS ON RHEOLOGICAL PROPERTIES OF SOLVENTLESS MAGNETIC INK. (R826728)

    EPA Science Inventory

    The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...

  18. Nanometal-Oxide Sunscreen Agents by Capillary Electrophoresis-Inductively Coupled Plasma Mass Spectrometry

    EPA Science Inventory

    Capillary electrophoresis with detection by ICPMS is being explored to characterize nanomaterials in waste water treatment plant effluents. TiO2 and ZnO, being widely used as UV filters in personal care products, plastics, and paints, are of concern as they enter the environment...

  19. Sugar beet pulp and poly(lactic acid) composites using methylene diphenyl diisocyanate as coupling agent

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Composites from sugar beet pulp (SBP) and poly(lactic acid) (PLA) were extruded in the presence of polymeric methylene diphenyl diisocyanate (pMDI). SBP particles were evenly distributed within the PLA matrix phase as revealed by confocal fluorescence microscopic analysis. The resultant composites w...

  20. Surface modification of apatite-wollastonite glass ceramic by synthetic coupling agent

    NASA Astrophysics Data System (ADS)

    Long, Qin; Zhou, Da-Li; Zhang, Xiang; Zhou, Jia-Bei

    2014-06-01

    In this study, lysine was introduced into the surface of apatite—wollastonite glass ceramic (AW-GC) to improve its cytocompatibility by two steps reaction procedure. Firstly, lysine connected to N-?-(aminoethyl)-?-aminopropyl trimethoxy silane (A-1120) by covalent binding of amide group. Secondly, the lysine-functionalized A-1120 was deposited on the surface of AW-GC through a silanization reaction involving a covalent attachment. FTIR spectra indicated that lysine had been immobilized onto the surface of AW-GC successfully. Bioactivity of the surface modified AW-GC was investigated by simulated body fluid (SBF), and the in vitro cytocompatibility was evaluated by coculturing with human osteosarcoma cell MG63. The results showed that the process of hydroxyapatite layer formed on the modified material was similar to AW-GC while the mode of hydroxyapatite deposition was changed. The growth of MG63 cells showed that modifying the AW-GC surface with lysine enhances the cell adhesion and proliferation.

  1. Marriage Equality for Same-Sex Couples: Counseling Psychologists as Social Change Agents

    ERIC Educational Resources Information Center

    Rostosky, Sharon S.; Riggle, Ellen D. B.

    2011-01-01

    The denial of civil marriage rights is a specific example of minority stress that can negatively affect the psychosocial well-being of self-identified lesbian, gay, bisexual, transgender, and queer (LGBTQ) individuals in same-sex partnerships, their families, and their allies. Counseling psychologists have an important role in addressing the…

  2. Effect of coupling agents on the weathering characteristics of bio-fiber composites

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Bio-fiber polymer composites (BFPC) are composite materials made from a thermoplastic or thermoset resin (substrate) with cellulosic fibers as fillers or reinforcement. BFPC have shown a significant growth in the last decade as a building product, automotive parts, and landscaping products. BFPC com...

  3. Effect of particle size, coupling agent and DDGS additions on Paulownia wood polypropylene composites

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The mechanical, flexural, thermal, and physical characteristics of wood plastic composites employing Paulownia wood (PP) flour derived from 36-mo-old trees blended with polypropylene (PP) were analyzed. Composites of 25% and 40% w/w of PW and 0-10% by weight of maleated polypropylene (MAPP) were pr...

  4. Polymeric coupling agents for enhancing the adhesion of epoxy to steel-II

    SciTech Connect

    Vaidesswaran, K.; Bell, J.P.; Nikles, D.E.

    1996-12-31

    Steel is one of the most versatile materials known to mankind. It is used in a variety of applications. In many of these applications, it is exposed to the atmosphere, leading to rust formation, which weakens structures made using steel. Hence, protection is important. The popular methods to prevent corrosion are painting, galvanizing, electroplating etc. The widely used Chrome etching process is very effective in corrosion inhibition as well as in hardening the steel. But, Chromium and its compounds are highly placed among the toxic chemicals listed under pollution prevention initiatives of the EPA. Hence, it was decided to find alternatives to this process.

  5. A localized crystallization to hierarchical ZSM-5 microspheres aided by silane coupling agent.

    PubMed

    Xiao, Qiang; Yao, Qiongsi; Zhuang, Jin; Liu, Gang; Zhong, Yijun; Zhu, Weidong

    2013-03-15

    Hierarchical ZSM-5 microspheres were synthesized from a ZSM-5 synthesis solution with the addition of 3-aminopropyltriethoxysilane (APTES). The time dependent revolution of structure and morphology was investigated by XRD, SEM, TEM, N(2) adsorption-desorption, and (29)Si MAS NMR techniques. The results indicated that amorphous aluminosilicate microspheres with diameter of 8 ?m were obtained at the initial stage of the synthesis. With the crystallization going on, the amorphous aluminosilicates gradually crystallized to ZSM-5 structure while preserving the spherical morphology. For the first time, a novel phenomenon of localized crystallization of ZSM-5 has been demonstrated in a conventional zeolitic synthesis solution aided by APTES. Moreover, after removing the amorphous silicic residues, the hierarchical ZSM-5 microspheres showed excellent catalytic properties in benzylation of benzene and catalytic cracking of polypropene. PMID:23321427

  6. Marriage Equality for Same-Sex Couples: Counseling Psychologists as Social Change Agents

    ERIC Educational Resources Information Center

    Rostosky, Sharon S.; Riggle, Ellen D. B.

    2011-01-01

    The denial of civil marriage rights is a specific example of minority stress that can negatively affect the psychosocial well-being of self-identified lesbian, gay, bisexual, transgender, and queer (LGBTQ) individuals in same-sex partnerships, their families, and their allies. Counseling psychologists have an important role in addressing the…

  7. Studies of thiol additions of silane coupling agents by vibrational spectroscopy

    NASA Astrophysics Data System (ADS)

    Li, Ying-Sing; Vecchio, N. E.

    2007-08-01

    Raman and infrared spectroscopies have been used to determine the addition reaction of mercaptopropyltrimethoxysilane (MPTMS) to allyltrimethoxysilane (ATMS) and 7-octenyltrichlorosilane based on the vibrational intensity variation of thiol and vinyl groups in the reaction mixtures. Due to the distinct and moderate intensity of Raman bands observed in the present experiment, the identification with Raman spectroscopic method is more sensitive than that with FTIR spectroscopy. In the presence of UV radiation, thiol addition reaction has been observed in the direct mixing samples of silanes. Hybrid sol-gels prepared with the use of MPTMS and ATMS as precursors in both acidic and basic conditions have revealed the progression of thiol addition under the UV radiation exposure. UV radiation is similarly effective to induce the thiol addition in the sol-gel coated aluminum tiles. Without UV radiation, the use of free radical initiator in the sol-gel samples might also help to induce the addition reaction.

  8. The role of silane coupling agents in glass/polymer composites

    SciTech Connect

    Wu, H.F.; Diwanji, A.P.

    1996-12-31

    The properties of the fiber-matrix interphase in glass-fiber reinforced composites can play a dominant role in governing the overall composite performance. Understanding the interactions occurring at the interphase and being able to tailor them to give a desired composite property is of great importance. In this paper, a single-filament mimic of a commercial glass-fiber reinforcement manufacturing process was used to apply amino and methacryloxy silanes with one, two, and three silanols (mono-ol,di-ol, and tri-ol) to two different glass fibers. Surface analyses by Angular-Dependent X-ray Photoelectron Spectroscopy (ADXPS), Electric-Kinetic Analysis (EKA), and contact angle measurements were used to characterize the surface coatings. Micro-indentation test was used to evaluate fiber-matrix interfacial adhesion. Changes observed in surface chemistry, micromechanics, and composite mechanical properties as a function of the type silanol are discussed.

  9. New application of silane coupling agents for covalently binding antibodies to glass and cellulose solid supports.

    PubMed

    Pope, N M; Kulcinski, D L; Hardwick, A; Chang, Y A

    1993-01-01

    Bifunctional silane reagents (3-iodopropyl)trimethoxysilane (1), (gamma-glycidoxypropyl)trimethoxysilane (2), and [1-(trimethoxysilyl)-2-(m- (or p-)chloromethyl)phenyl]ethane (3) were used to covalently link goat anti-mouse (GAM) antibodies (Ab) to glass microbeads and cuprammonium rayon hollow-fiber dialyzers. An average of 0.79 and 0.83 microgram of GAM Ab/cm2 was immobilized on the hollow-fiber dialyzers and the glass beads, respectively. The antibodies immobilized on glass microbeads or on hollow-fiber dialyzers were then used to selectively deplete CD34+ cells or CD4+ peripheral blood mononuclear cells (PBMC), respectively. Glass microbeads depleted 80% CD34+ cells with good selectivity, and the hollow-fiber dialyzers depleted an average of 81% CD4+ PBMC. PMID:7873648

  10. Synthesis of nano-hydroxyapatite and its rapid mediated surface functionalization by silane coupling agent.

    PubMed

    Rehman, Sarish; Khan, Kishwar; Mujahid, Mohammad; Nosheen, Shaneela

    2016-01-01

    In this work, hydroxyapatite (HA) nanorods were synthesized by simple one step wet precipitation method followed by their rapid surface functionalization via aminopropyltriethoxysilane (APTS) to give modified (HA-APTS) product. Functionalized hydroxyapatite (HA-APTS) holds amino groups on their surface that can be further functionalized with other bioactive molecules. The extent of functionalization of HA was studied under three different processing conditions; at room temperature, at 80 °C and under microwave condition (600 W). Three different temperatures have been use for the purpose of comparison between the functionalized products so that we can judge that whether there is any effect of temperature on the final products. In the last we conclude that temperature has no effect. So microwave condition is best to carried out the functionalization in just 5 min. PMID:26478359

  11. Microscale immunosensors for biological agents

    NASA Astrophysics Data System (ADS)

    Bange, Adam; Wong, Danny K. Y.; Seliskar, Carl J.; Halsall, H. B.; Heineman, William R.

    2005-01-01

    Microbead immunoassay with electrochemical detection has been developed as a sensitive and selective technique for rapid and small volume analyses. In this assay, applications of paramagnetic microbeads in a microfluidic system have aided the automation of all assay steps to enable near-continuous monitoring. These mobile microbeads can be transported through microchannels, captured and held at specific points by a magnet. Hence, by performing immunoassay on microbeads, they can be dispersed throughout a small sample of water, where they provide a large surface area to sample volume ratio that enhances the capture of the target antigen by minimizing diffusional distances. They can then be collected magnetically and manipulated to accomplish all the assay steps to determine if any target was captured. In addition, the microbeads can be accommodated in small volumes, which reduces the dilution of the enzyme product in the detection step thus maximizing sensitivity. Further, electrochemical detection coupled with enzyme-labeled immunoassay has led to the development of a sensitive analytical technique. In this area, interdigitated array electrodes are particularly suited to microfluidics. Improved sensitivity is obtained by redox cycling of the species being detected. In this work, the microbead immunoassays is demonstrated for the virus MS2 bacteriophage.

  12. 3DGIS-Based Multi-Agent Geosimulation and Visualization of Building Evacuation Using GAMA Platform

    NASA Astrophysics Data System (ADS)

    Macatulad, E. G.; Blanco, A. C.

    2014-11-01

    Recent GIS applications have already extended analyses from the traditional 2-2.5D environment (x,y,attributes) to 3D space (x,y,z,attributes). Coupled with agent-based modeling (ABM), available 3DGIS data can be used to develop simulation models for improved analysis of spatial data and spatial processes. One such application is on building evacuation for which ABM is integrated with 3D indoor spatial data to model human behavior during evacuation events and simulate evacuation scenarios visualized in 3D. The research presented in this paper develops a multi-agent geosimulation model for building evacuation, integrating 3DGIS dataset of the case study building as input in ABM using the GAMA simulation platform. This model is intended to complement and improve traditional approaches in building evacuation planning and management such as earthquake and fire drills. The initial model developed includes PEOPLE agents to model the building occupants, and FLOORS, ROOMS, INDOOR_PATHS and EXIT_POINTS agents, which are modeled from the 3DGIS layers. The INDOOR_PATHS and EXIT_POINTS agents influence the movement of PEOPLE agents. Test simulations were performed involving PEOPLE agents placed in rooms of the building based on potential number of occupants computed based from the floor area of each room. The PEOPLE agents are programmed to find the shortest path along the INDOOR_PATHS towards the EXIT_POINTS instance designated for each room of the building. The simulation computes for the total time it takes for all PEOPLE agents to exit the building.

  13. Reinforcement Learning Multi-Agent Modeling of Decision-Making Agents for the Study of Transboundary Surface Water Conflicts with Application to the Syr Darya River Basin

    NASA Astrophysics Data System (ADS)

    Riegels, N.; Siegfried, T.; Pereira Cardenal, S. J.; Jensen, R. A.; Bauer-Gottwein, P.

    2008-12-01

    In most economics--driven approaches to optimizing water use at the river basin scale, the system is modelled deterministically with the goal of maximizing overall benefits. However, actual operation and allocation decisions must be made under hydrologic and economic uncertainty. In addition, river basins often cross political boundaries, and different states may not be motivated to cooperate so as to maximize basin- scale benefits. Even within states, competing agents such as irrigation districts, municipal water agencies, and large industrial users may not have incentives to cooperate to realize efficiency gains identified in basin- level studies. More traditional simulation--optimization approaches assume pre-commitment by individual agents and stakeholders and unconditional compliance on each side. While this can help determine attainable gains and tradeoffs from efficient management, such hardwired policies do not account for dynamic feedback between agents themselves or between agents and their environments (e.g. due to climate change etc.). In reality however, we are dealing with an out-of-equilibrium multi-agent system, where there is neither global knowledge nor global control, but rather continuous strategic interaction between decision making agents. Based on the theory of stochastic games, we present a computational framework that allows for studying the dynamic feedback between decision--making agents themselves and an inherently uncertain environment in a spatially and temporally distributed manner. Agents with decision-making control over water allocation such as countries, irrigation districts, and municipalities are represented by reinforcement learning agents and coupled to a detailed hydrologic--economic model. This approach emphasizes learning by agents from their continuous interaction with other agents and the environment. It provides a convenient framework for the solution of the problem of dynamic decision-making in a mixed cooperative / non-cooperative environment with which different institutional setups and incentive systems can be studied so to identify reasonable ways to reach desirable, Pareto--optimal allocation outcomes. Preliminary results from an application to the Syr Darya river basin in Central Asia will be presented and discussed. The Syr Darya River is a classic example of a transboundary river basin in which basin-wide efficiency gains identified in optimization studies have not been sufficient to induce cooperative management of the river by the riparian states.

  14. Can Space Applications Benefit from Intelligent Agents?

    NASA Astrophysics Data System (ADS)

    Varghese, Blesson; McKee, Gerard

    The work reported in this paper proposes a Swarm-Array computing approach based on 'Intelligent Agents' to apply autonomic computing concepts to parallel computing systems and build reliable systems for space applications. Swarm-array computing is a swarm robotics inspired, novel computing approach considered as a path to achieve autonomy in parallel computing systems. In the intelligent agent approach, a task to be executed on parallel computing cores is considered as a swarm of autonomous agents. A task is carried to a computing core by carrier agents and can be seamlessly transferred between cores in the event of a predicted failure, thereby achieving self-* objectives of autonomic computing. The approach is validated on a multi-agent simulator.

  15. An agent based model of genotype editing

    SciTech Connect

    Rocha, L. M.; Huang, C. F.

    2004-01-01

    This paper presents our investigation on an agent-based model of Genotype Editing. This model is based on several characteristics that are gleaned from the RNA editing system as observed in several organisms. The incorporation of editing mechanisms in an evolutionary agent-based model provides a means for evolving agents with heterogenous post-transcriptional processes. The study of this agent-based genotype-editing model has shed some light into the evolutionary implications of RNA editing as well as established an advantageous evolutionary computation algorithm for machine learning. We expect that our proposed model may both facilitate determining the evolutionary role of RNA editing in biology, and advance the current state of research in agent-based optimization.

  16. Removing fracture fluid via chemical blowing agents

    SciTech Connect

    Abou-Sayed, I.; Hazlett, R.D

    1989-05-23

    A method is described for enhancing removal of fracture fluid from a formation or reservoir comprising: (a) placing into a fracturing fluid a chemical blowing agent in an amount sufficient upon decomposition of the agent to create gas sufficient to remove the fracture fluid from the formation where the chemical blowing agent is a member selected from the group consisting of dinitrosopentamethylenetetramine, sodium hydrogen carbonate and p-toluene sulfonyl hydrazide, azodicarbonamide, and p,p-oxybis (benzenesulfonyl hydrazide); (b) fracturing the formation and causing the chemical blowing agent to decompose after completion of the fracturing; and (c) completing the fracturing and decomposing the chemical blowing agent thereby liberating gas in an amount sufficient to remove the fracture fluid from the formation's matrix which enhances production of the fracture fluid from the formation.

  17. Trust method for multi-agent consensus

    NASA Astrophysics Data System (ADS)

    Mikulski, Dariusz G.; Lewis, Frank L.; Gu, Edward Y.; Hudas, Greg R.

    2012-06-01

    The consensus problem in multi-agent systems often assumes that all agents are equally trustworthy to seek agreement. But for multi-agent military applications - particularly those that deal with sensor fusion or multi-robot formation control - this assumption may create the potential for compromised network security or poor cooperative performance. As such, we present a trust-based solution for the discrete-time multi-agent consensus problem and prove its asymptotic convergence in strongly connected digraphs. The novelty of the paper is a new trust algorithm called RoboTrust, which is used to calculate trustworthiness in agents using observations and statistical inferences from various historical perspectives. The performance of RoboTrust is evaluated within the trust-based consensus protocol under different conditions of tolerance and confirmation.

  18. Ecology Based Decentralized Agent Management System

    NASA Technical Reports Server (NTRS)

    Peysakhov, Maxim D.; Cicirello, Vincent A.; Regli, William C.

    2004-01-01

    The problem of maintaining a desired number of mobile agents on a network is not trivial, especially if we want a completely decentralized solution. Decentralized control makes a system more r e bust and less susceptible to partial failures. The problem is exacerbated on wireless ad hoc networks where host mobility can result in significant changes in the network size and topology. In this paper we propose an ecology-inspired approach to the management of the number of agents. The approach associates agents with living organisms and tasks with food. Agents procreate or die based on the abundance of uncompleted tasks (food). We performed a series of experiments investigating properties of such systems and analyzed their stability under various conditions. We concluded that the ecology based metaphor can be successfully applied to the management of agent populations on wireless ad hoc networks.

  19. Vibrational coupled cluster theory

    NASA Astrophysics Data System (ADS)

    Christiansen, Ove

    2004-02-01

    The theory and first implementation of a vibrational coupled cluster (VCC) method for calculations of the vibrational structure of molecules is presented. Different methods for introducing approximate VCC methods are discussed including truncation according to a maximum number of simultaneous mode excitations as well as an interaction space order concept is introduced. The theory is tested on calculation of anharmonic frequencies for a three-mode model system and a formaldehyde quartic force field. The VCC method is compared to vibrational self-consistent-field, vibrational Møller-Plesset perturbation theory, and vibrational configuration interaction (VCI). A VCC calculation typically gives higher accuracy than a corresponding VCI calculation with the same number of parameters and the same formal operation count.

  20. Coupled quantum Otto cycle.

    PubMed

    Thomas, George; Johal, Ramandeep S

    2011-03-01

    We study the one-dimensional isotropic Heisenberg model of two spin-1/2 systems as a quantum heat engine. The engine undergoes a four-step Otto cycle where the two adiabatic branches involve changing the external magnetic field at a fixed value of the coupling constant. We find conditions for the engine efficiency to be higher than in the uncoupled model; in particular, we find an upper bound which is tighter than the Carnot bound. A domain of parameter values is pointed out which was not feasible in the interaction-free model. Locally, each spin seems to cause a flow of heat in a direction opposite to the global temperature gradient. This feature is explained by an analysis of the local effective temperature of the spins. PMID:21517482

  1. Fluid structure coupling algorithm

    SciTech Connect

    McMaster, W.H.; Gong, E.Y.; Landram, C.S.; Quinones, D.F.

    1980-04-10

    A fluid-structure-interaction algorithm has been developed and incorporated into the two-dimensional code PELE-IC. This code combines an Eulerian incompressible fluid algorithm with a Lagrangian finite element shell algorithm and incorporates the treatment of complex free surfaces. The fluid structure and coupling algorithms have been verified by the calculation of solved problems from the literature and from air and steam blowdown experiments. The code has been used to calculate loads and structural response from air blowdown and the oscillatory condensation of steam bubbles in water suppression pools typical of boiling water reactors. The techniques developed have been extended to three dimensions and implemented in the computer code PELE-3D.

  2. Hardware accelerated high performance neutron transport computation based on AGENT methodology

    NASA Astrophysics Data System (ADS)

    Xiao, Shanjie

    The spatial heterogeneity of the next generation Gen-IV nuclear reactor core designs brings challenges to the neutron transport analysis. The Arbitrary Geometry Neutron Transport (AGENT) AGENT code is a three-dimensional neutron transport analysis code being developed at the Laboratory for Neutronics and Geometry Computation (NEGE) at Purdue University. It can accurately describe the spatial heterogeneity in a hierarchical structure through the R-function solid modeler. The previous version of AGENT coupled the 2D transport MOC solver and the 1D diffusion NEM solver to solve the three dimensional Boltzmann transport equation. In this research, the 2D/1D coupling methodology was expanded to couple two transport solvers, the radial 2D MOC solver and the axial 1D MOC solver, for better accuracy. The expansion was benchmarked with the widely applied C5G7 benchmark models and two fast breeder reactor models, and showed good agreement with the reference Monte Carlo results. In practice, the accurate neutron transport analysis for a full reactor core is still time-consuming and thus limits its application. Therefore, another content of my research is focused on designing a specific hardware based on the reconfigurable computing technique in order to accelerate AGENT computations. It is the first time that the application of this type is used to the reactor physics and neutron transport for reactor design. The most time consuming part of the AGENT algorithm was identified. Moreover, the architecture of the AGENT acceleration system was designed based on the analysis. Through the parallel computation on the specially designed, highly efficient architecture, the acceleration design on FPGA acquires high performance at the much lower working frequency than CPUs. The whole design simulations show that the acceleration design would be able to speedup large scale AGENT computations about 20 times. The high performance AGENT acceleration system will drastically shortening the computation time for 3D full-core neutron transport analysis, making the AGENT methodology unique and advantageous, and thus supplies the possibility to extend the application range of neutron transport analysis in either industry engineering or academic research.

  3. For whom will the Bayesian agents vote?

    NASA Astrophysics Data System (ADS)

    Caticha, Nestor; Cesar, Jonatas; Vicente, Renato

    2015-04-01

    Within an agent-based model where moral classifications are socially learned, we ask if a population of agents behaves in a way that may be compared with conservative or liberal positions in the real political spectrum. We assume that agents first experience a formative period, in which they adjust their learning style acting as supervised Bayesian adaptive learners. The formative phase is followed by a period of social influence by reinforcement learning. By comparing data generated by the agents with data from a sample of 15000 Moral Foundation questionnaires we found the following. 1. The number of information exchanges in the formative phase correlates positively with statistics identifying liberals in the social influence phase. This is consistent with recent evidence that connects the dopamine receptor D4-7R gene, political orientation and early age social clique size. 2. The learning algorithms that result from the formative phase vary in the way they treat novelty and corroborative information with more conservative-like agents treating it more equally than liberal-like agents. This is consistent with the correlation between political affiliation and the Openness personality trait reported in the literature. 3. Under the increase of a model parameter interpreted as an external pressure, the statistics of liberal agents resemble more those of conservative agents, consistent with reports on the consequences of external threats on measures of conservatism. We also show that in the social influence phase liberal-like agents readapt much faster than conservative-like agents when subjected to changes on the relevant set of moral issues. This suggests a verifiable dynamical criterium for attaching liberal or conservative labels to groups.

  4. Single step coupling for multi-responsive water-based chitin/chitosan magnetic nanoparticles.

    PubMed

    Chatrabhuti, Sutima; Chirachanchai, Suwabun

    2013-09-12

    Coupling of chitin whisker (CTWK) or water-soluble chitosan (WSCS) with magnetic nanoparticles (MAG) via a covalent linkage by using a silane coupling agent in an aqueous system is proposed. The use of the silane coupling agent glycidoxypropyltrimethoxy, having a trimethoxy silane as well as an epoxide functionality, allows one step coupling between CTWK or WSCS and MAG. The MAG derivatives obtained are well dispersed and their colloidal aqueous solutions can be stabilized for days. An external magnetic field initiates alignment of nano-rod structured CTWK-MAG in the direction of the magnetic field. The uniqueness of these two materials is that CTWK-MAG shows solvent polarity responsiveness whereas WSCS-MAG performs pH responsiveness. A model application study on DNA extraction confirms that WSCS-MAG with positively charged at pH 7 and with high surface area performs more Escherichia coli extraction ability for two times as compared to CTWK-MAG. PMID:23911469

  5. Strong-coupling effects in dissipatively coupled optomechanical systems

    NASA Astrophysics Data System (ADS)

    Weiss, Talitha; Bruder, Christoph; Nunnenkamp, Andreas

    2013-04-01

    In this paper, we study cavity optomechanical systems in which the position of a mechanical oscillator modulates both the resonance frequency (dispersive coupling) and the linewidth (dissipative coupling) of a cavity mode. Using a quantum noise approach, we calculate the optical damping and the optically induced frequency shift. We find that dissipatively coupled systems feature two parameter regions providing amplification and two parameter regions providing cooling. To investigate the strong-coupling regime, we solve the linearized equations of motion exactly and calculate the mechanical and optical spectra. In addition to signatures of normal-mode splitting that are similar to the case of purely dispersive coupling, the spectra contain a striking feature that we trace back to the Fano line shape of the force spectrum. Finally, we show that purely dissipative coupling can lead to optomechanically induced transparency which will provide an experimentally convenient way of observing normal-mode splitting.

  6. Black hole temperature: Minimal coupling vs conformal coupling

    SciTech Connect

    Fazel, Mohamadreza; Mirza, Behrouz; Mansoori, Seyed Ali Hosseini

    2014-05-15

    In this article, we discuss the propagation of scalar fields in conformally transformed spacetimes with either minimal or conformal coupling. The conformally coupled equation of motion is transformed into a one-dimensional Schrödinger-like equation with an invariant potential under conformal transformation. In a second stage, we argue that calculations based on conformal coupling yield the same Hawking temperature as those based on minimal coupling. Finally, it is conjectured that the quasi normal modes of black holes are invariant under conformal transformation.

  7. Gay and lesbian couples in Italy: comparisons with heterosexual couples.

    PubMed

    Antonelli, Paolo; Dèttore, Davide; Lasagni, Irene; Snyder, Douglas K; Balderrama-Durbin, Christina

    2014-12-01

    Assessing couple relationships across diverse languages and cultures has important implications for both clinical intervention and prevention. This is especially true for nontraditional relationships potentially subject to various expressions of negative societal evaluation or bias. Few empirically validated measures of relationship functioning have been developed for cross-cultural applications, and none have been examined for their psychometric sufficiency for evaluating same-sex couples across different languages and cultures. The current study examined the psychometric properties of an Italian translation of the Marital Satisfaction Inventory - Revised (MSI-R), a 150-item 13-scale measure of couple relationship functioning, for its use in assessing the intimate relationships of gay and lesbian couples in Italy. Results for these couples were compared to data from heterosexual married and unmarried cohabiting couples from the same geographical region, as well as to previously published data for gay, lesbian, and unmarried heterosexual couples from the United States. Findings suggest that, despite unique societal pressures confronting Italian same-sex couples, these relationships appear resilient and fare well both overall and in specific domains of functioning compared to heterosexual couples both in Italy and the United States. PMID:24867576

  8. A user-system interface agent

    NASA Technical Reports Server (NTRS)

    Wakim, Nagi T.; Srivastava, Sadanand; Bousaidi, Mehdi; Goh, Gin-Hua

    1995-01-01

    Agent-based technologies answer to several challenges posed by additional information processing requirements in today's computing environments. In particular, (1) users desire interaction with computing devices in a mode which is similar to that used between people, (2) the efficiency and successful completion of information processing tasks often require a high-level of expertise in complex and multiple domains, (3) information processing tasks often require handling of large volumes of data and, therefore, continuous and endless processing activities. The concept of an agent is an attempt to address these new challenges by introducing information processing environments in which (1) users can communicate with a system in a natural way, (2) an agent is a specialist and a self-learner and, therefore, it qualifies to be trusted to perform tasks independent of the human user, and (3) an agent is an entity that is continuously active performing tasks that are either delegated to it or self-imposed. The work described in this paper focuses on the development of an interface agent for users of a complex information processing environment (IPE). This activity is part of an on-going effort to build a model for developing agent-based information systems. Such systems will be highly applicable to environments which require a high degree of automation, such as, flight control operations and/or processing of large volumes of data in complex domains, such as the EOSDIS environment and other multidisciplinary, scientific data systems. The concept of an agent as an information processing entity is fully described with emphasis on characteristics of special interest to the User-System Interface Agent (USIA). Issues such as agent 'existence' and 'qualification' are discussed in this paper. Based on a definition of an agent and its main characteristics, we propose an architecture for the development of interface agents for users of an IPE that is agent-oriented and whose resources are likely to be distributed and heterogeneous in nature. The architecture of USIA is outlined in two main components: (1) the user interface which is concerned with issues as user dialog and interaction, user modeling, and adaptation to user profile, and (2) the system interface part which deals with identification of IPE capabilities, task understanding and feasibility assessment, and task delegation and coordination of assistant agents.

  9. Aqueous microwaves assisted cross-coupling reactions applied to unprotected nucleosides.

    NASA Astrophysics Data System (ADS)

    Len, Christophe; Hervé, Gwénaelle

    2015-02-01

    Nucleoside analogues have attracted much attention due to their potential biological activities. Amongst all synthetic nucleosides, C5-modified pyrimidines and C7- or C8-modified purines have mostly been prepared using palladium cross-coupling reactions and then studied as antitumoral and antiviral agents. Our objective is to focus this review on the Suzuki-Miyaura and on the Heck cross-couplings of nucleosides using microwave irradiations which are an alternative technology compatible with green chemistry and sustainable development.

  10. Pseudo-peptides as novel antileptospiral agents: synthesis and spectral characterization.

    PubMed

    Shivamallu, Chandan; Sharanaiah, Umesha; Kollur, Shiva Prasad; Mallesh, Naveen Kumar R; Hosakere, Revanasiddappa D; Balamurugan, V

    2014-01-24

    In this paper, we describe the synthesis of novel class of pseudo-peptides derived by coupling an amino acid with a heterocyclic moiety containing free amine group using suitable coupling agents. The synthesized compounds were characterized using spectral ((1)H NMR, (13)C NMR and MS) techniques. Preliminary pharmacological assays for Leptospirosis were studied by test tube dilution (TDT) and micro dilution technique (MDT). In particular, all the analyses led to the conclusion that the synthesized compound inhibiting the Leptospira a causal organism of Leptospirosis. PMID:24184586

  11. Pseudo-peptides as novel antileptospiral agents: Synthesis and spectral characterization

    NASA Astrophysics Data System (ADS)

    Shivamallu, Chandan; Sharanaiah, Umesha; Kollur, Shiva Prasad; Mallesh, Naveen Kumar R.; Hosakere, Revanasiddappa D.; Balamurugan, V.

    2014-01-01

    In this paper, we describe the synthesis of novel class of pseudo-peptides derived by coupling an amino acid with a heterocyclic moiety containing free amine group using suitable coupling agents. The synthesized compounds were characterized using spectral (1H NMR, 13C NMR and MS) techniques. Preliminary pharmacological assays for Leptospirosis were studied by test tube dilution (TDT) and micro dilution technique (MDT). In particular, all the analyses led to the conclusion that the synthesized compound inhibiting the Leptospira a causal organism of Leptospirosis.

  12. Progress in Nanotechnology Based Approaches to Enhance the Potential of Chemopreventive Agents

    PubMed Central

    Muqbil, Irfana; Masood, Ashiq; Sarkar, Fazlul H.; Mohammad, Ramzi M.; Azmi, Asfar S.

    2011-01-01

    Cancer chemoprevention is defined as the use of natural agents to suppress, reverse or prevent the carcinogenic process from turning into aggressive cancer. Over the last two decades, multiple natural dietary compounds with diverse chemical structures such flavonoids, tannins, curcumins and polyphenols have been proposed as chemopreventive agents. These agents have proven excellent anticancer potential in the laboratory setting, however, the observed effects in vitro do not translate in clinic where they fail to live up to their expectations. Among the various reasons for this discrepancy include inefficient systemic delivery and robust bioavailability. To overcome this barrier, researchers have focused towards coupling these agents with nano based encapsulation technology that in principle will enhance bioavailability and ultimately benefit clinical outcome. The last decade has witnessed rapid advancement in the development of nanochemopreventive technology with emergence of many nano encapsulated formulations of different dietary anticancer agents. This review summarizes the most up-to-date knowledge on the studies performed in nanochemoprevention, their proposed use in the clinic and future directions in which this field is heading. As the knowledge of the dynamics of nano encapsulation evolves, it is expected that researchers will bring forward newer and far more superior nanochemopreventive agents that may become standard drugs for different cancers. PMID:24212623

  13. Bendamustine: rescue of an effective antineoplastic agent from the mid-twentieth century.

    PubMed

    Leoni, Lorenzo M

    2011-04-01

    Although the alkylating agent bendamustine was developed in Germany in the mid-twentieth century, it has only recently come to the forefront in the rest of the world as an effective chemotherapeutic agent for the treatment of several hematologic malignancies. Based on the activity demonstrated in single-arm and randomized trials, this nitrogen mustard is approved by the US Food and Drug Administration (FDA) for the treatment of chronic lymphocytic leukemia and rituximab-refractory indolent non-Hodgkin lymphoma. The unique structural and mechanistic features of bendamustine differentiate it from other alkylating agents, providing increased stability and potency in DNA cross linking and subsequent cytotoxicity. Due to its unusual development, few studies have closely examined the mechanisms of action for this nitrogen mustard and many unanswered questions remain. Additionally, phase I and pharmacokinetic studies are limited, although increased understanding of the clinical pharmacology of bendamustine led to development of dosing recommendations by international experts based on the available data. The clinical activity of bendamustine as a single agent and in combination with other chemotherapeutic and immunotherapeutic drugs, coupled with its potential lack of cross-resistance with many other chemotherapy agents, make bendamustine an attractive therapy for patients with newly diagnosed and refractory hematologic malignancies. This review will discuss the development of bendamustine, its structural and pharmacologic characteristics, and current data regarding the optimal dosing of this agent in specific clinical settings. PMID:21530771

  14. Hypersensitivity reactions during treatment with biological agents.

    PubMed

    Puxeddu, Ilaria; Caltran, Elena; Rocchi, Valeria; Del Corso, Isabella; Tavoni, Antonio; Migliorini, Paola

    2016-01-01

    The recent development of biological agents, namely, anti-tumour necrosis factor alpha (TNF-?) agents (infliximab, adalimumab and etanercept), anti- CD20 monoclonal antibody (rituximab) and anti-interleukin 6 receptor (IL-6R) monoclonal antibody (tocilizumab), represents a major breakthrough for the treatment of immune-mediated disorders. Given their structural and functional differences, distinct safety profiles can be expected for each of these agents. Evidence in the literature indicates that patients treated with anti-TNF-? agents and tocilizumab are at increased risk for bacterial infections. However, an increased therapeutic use of these biological agents has disclosed other side-effects, including immediate hypersensitivity reactions, such as anaphylaxis and urticaria. Both under-diagnosis and over-diagnosis of hypersensitivity reactions to biological agents are potential problems. Thus, it is important to identify these reactions and to adopt the right approach to manage them. This article reviews the general aspects of adverse events during biologic treatment, focusing on IgE-mediated hypersensitivity reactions to anti-TNF-? agents, rituximab and tocilizumab, and on the tools for the diagnosis of these life-threatening reactions. PMID:26751942

  15. [Decorporation agents for internal radioactive contamination].

    PubMed

    Ohmachi, Yasushi

    2015-01-01

    When radionuclides are accidentally ingested or inhaled, blood circulation or tissue/organ deposition of the radionuclides causes systemic or local radiation effects. In such cases, decorporation therapy is used to reduce the health risks due to their intake. Decorporation therapy includes reduction and/or inhibition of absorption from the gastrointestinal tract, isotopic dilution, and the use of diuretics, adsorbents, and chelating agents. For example, penicillamine is recommended as a chelating agent for copper contamination, and diethylene triamine pentaacetic acid is approved for the treatment of internal contamination with plutonium. During chelation therapy, the removal effect of the drugs should be monitored using a whole-body counter and/or bioassay. Some authorities, such as the National Council on Radiation Protection and Measurements and International Atomic Energy Agency, have reported recommended decorporation agents for each radionuclide. However, few drugs are approved by the US Food and Drug Administration, and many are off-label-use agents. Because many decontamination agents are drugs that have been available for a long time and have limited efficacy, the development of new, higher-efficacy drugs has been carried out mainly in the USA and France. In this article, in addition to an outline of decorporation agents for internal radioactive contamination, an outline of our research on decorporation agents for actinide (uranium and plutonium) contamination and for radio-cesium contamination is also presented. PMID:25832835

  16. Persistent agents in Axelrod's social dynamics model

    NASA Astrophysics Data System (ADS)

    Reia, Sandro M.; Neves, Ubiraci P. C.

    2016-01-01

    Axelrod's model of social dynamics has been studied under the effect of external media. Here we study the formation of cultural domains in the model by introducing persistent agents. These are agents whose cultural traits are not allowed to change but may be spread through local neighborhood. In the absence of persistent agents, the system is known to present a transition from a monocultural to a multicultural regime at some critical Q (number of traits). Our results reveal a dependence of critical Q on the occupation probability p of persistent agents and we obtain the phase diagram of the model in the (p,Q) -plane. The critical locus is explained by the competition of two opposite forces named here barrier and bonding effects. Such forces are verified to be caused by non-persistent agents which adhere (adherent agents) to the set of traits of persistent ones. The adherence (concentration of adherent agents) as a function of p is found to decay for constant Q. Furthermore, adherence as a function of Q is found to decay as a power law with constant p.

  17. Brahms Mobile Agents: Architecture and Field Tests

    NASA Technical Reports Server (NTRS)

    Clancey, William J.; Sierhuis, Maarten; Kaskiris, Charis; vanHoof, Ron

    2002-01-01

    We have developed a model-based, distributed architecture that integrates diverse components in a system designed for lunar and planetary surface operations: an astronaut's space suit, cameras, rover/All-Terrain Vehicle (ATV), robotic assistant, other personnel in a local habitat, and a remote mission support team (with time delay). Software processes, called agents, implemented in the Brahms language, run on multiple, mobile platforms. These mobile agents interpret and transform available data to help people and robotic systems coordinate their actions to make operations more safe and efficient. The Brahms-based mobile agent architecture (MAA) uses a novel combination of agent types so the software agents may understand and facilitate communications between people and between system components. A state-of-the-art spoken dialogue interface is integrated with Brahms models, supporting a speech-driven field observation record and rover command system (e.g., return here later and bring this back to the habitat ). This combination of agents, rover, and model-based spoken dialogue interface constitutes a personal assistant. An important aspect of the methodology involves first simulating the entire system in Brahms, then configuring the agents into a run-time system.

  18. Agent-Supported Mission Operations Teamwork

    NASA Technical Reports Server (NTRS)

    Malin, Jane T.

    2003-01-01

    This slide presentation reviews the development of software agents to support of mission operations teamwork. The goals of the work was to make automation by agents easy to use, supervise and direct, manage information and communication to decrease distraction, interruptions, workload and errors, reduce mission impact of off-nominal situations and increase morale and decrease turnover. The accomplishments or the project are: 1. Collaborative agents - mixed initiative and creation of instructions for mediating agent 2. Methods for prototyping, evaluating and evolving socio-technical systems 3. Technology infusion: teamwork tools in mISSIons 4. Demonstrations in simulation testbed An example of the use of agent is given, the use of an agent to monitor a N2 tank leak. An incomplete instruction to the agent is handled with mediating assistants, or Intelligent Briefing and Response Assistant (IBRA). The IBRA Engine also watches data stream for triggers and executes Act-Whenever actions. There is also a Briefing and Response Instruction (BRI) which is easy for a discipline specialist to create through a BRI editor.

  19. Scoping Planning Agents With Shared Models

    NASA Technical Reports Server (NTRS)

    Bedrax-Weiss, Tania; Frank, Jeremy D.; Jonsson, Ari K.; McGann, Conor

    2003-01-01

    In this paper we provide a formal framework to define the scope of planning agents based on a single declarative model. Having multiple agents sharing a single model provides numerous advantages that lead to reduced development costs and increase reliability of the system. We formally define planning in terms of extensions of an initial partial plan, and a set of flaws that make the plan unacceptable. A Flaw Filter (FF) allows us to identify those flaws relevant to an agent. Flaw filters motivate the Plan Identification Function (PIF), which specifies when an agent is is ready hand control to another agent for further work. PIFs define a set of plan extensions that can be generated from a model and a plan request. FFs and PIFs can be used to define the scope of agents without changing the model. We describe an implementation of PIFsand FFswithin the context of EUROPA, a constraint-based planning architecture, and show how it can be used to easily design many different agents.

  20. Biological agents database in the armed forces.

    PubMed

    Niemcewicz, Marcin; Kocik, Janusz; Bielecka, Anna; Wierciński, Michał

    2014-10-01

    Rapid detection and identification of the biological agent during both, natural or deliberate outbreak is crucial for implementation of appropriate control measures and procedures in order to mitigate the spread of disease. Determination of pathogen etiology may not only support epidemiological investigation and safety of human beings, but also enhance forensic efforts in pathogen tracing, collection of evidences and correct inference. The article presents objectives of the Biological Agents Database, which was developed for the purpose of the Ministry of National Defense of the Republic of Poland under the European Defence Agency frame. The Biological Agents Database is an electronic catalogue of genetic markers of highly dangerous pathogens and biological agents of weapon of mass destruction concern, which provides full identification of biological threats emerging in Poland and in locations of activity of Polish troops. The Biological Agents Database is a supportive tool used for tracing biological agents' origin as well as rapid identification of agent causing the disease of unknown etiology. It also provides support in diagnosis, analysis, response and exchange of information between institutions that use information contained in it. Therefore, it can be used not only for military purposes, but also in a civilian environment. PMID:25033774

  1. Biological agents as occupational hazards - selected issues.

    PubMed

    Dutkiewicz, Jacek; Cisak, Ewa; Sroka, Jacek; Wójcik-Fatla, Angelina; Zając, Violetta

    2011-12-01

    There are two main groups of biological agents regarded as occupational hazards: allergenic and/or toxic agents forming bioaerosols, and agents causing zoonoses and other infectious diseases. Bioaerosols occurring in the agricultural work environments comprise: bacteria, fungi, high molecular polymers produced by bacteria (endotoxin) or by fungi (β-glucans), low molecular secondary metabolites of fungi (mycotoxins, volatile organic compounds) and various particles of plant and animal origin. All these agents could be a cause of allergic and/or immunotoxic occupational diseases of respiratory organ (airways inflammation, rhinitis, toxic pneumonitis, hypersensitivity pneumonitis and asthma), conjunctivitis and dermatitis in exposed workers. Very important among zoonotic agents causing occupational diseases are those causing tick-borne diseases: Lyme borreliosis, anaplasmosis, babesiosis, bartonellosis. Agricultural workers in tropical zones are exposed to mosquito bites causing malaria, the most prevalent vector-borne disease in the world. The group of agents causing other, basically not vector-borne zoonoses, comprises those evoking emerging or re-emerging diseases of global concern, such as: hantaviral diseases, avian and swine influenza, Q fever, leptospiroses, staphylococcal diseases caused by the methicillin-resistant Staphylococcus aureus (MRSA) strains, and diseases caused by parasitic protozoa. Among other infectious, non-zoonotic agents, the greatest hazard for health care workers pose the blood-borne human hepatitis and immunodeficiency viruses (HBV, HCV, HIV). Of interest are also bacteria causing legionellosis in people occupationally exposed to droplet aerosols, mainly from warm water. PMID:22216801

  2. Natural chelating agents for radionuclide decorporation

    DOEpatents

    Premuzic, E.T.

    1985-06-11

    This invention relates to the production of metal-binding compounds useful for the therapy of heavy metal poisoning, for biological mining and for decorporation of radionuclides. The present invention deals with an orderly and effective method of producing new therapeutically effective chelating agents. This method uses challenge biosynthesis for the production of chelating agents that are specific for a particular metal. In this approach, the desired chelating agents are prepared from microorganisms challenged by the metal that the chelating agent is designed to detoxify. This challenge induces the formation of specific or highly selective chelating agents. The present invention involves the use of the challenge biosynthetic method to produce new complexing/chelating agents that are therapeutically useful to detoxify uranium, plutonium, thorium and other toxic metals. The Pseudomonas aeruginosa family of organisms is the referred family of microorganisms to be used in the present invention to produce the new chelating agent because this family is known to elaborate strains resistant to toxic metals.

  3. The Second-Agent Effect: Communicative Gestures Increase the Likelihood of Perceiving a Second Agent

    PubMed Central

    Manera, Valeria; Del Giudice, Marco; Bara, Bruno G.; Verfaillie, Karl; Becchio, Cristina

    2011-01-01

    Background Beyond providing cues about an agent's intention, communicative actions convey information about the presence of a second agent towards whom the action is directed (second-agent information). In two psychophysical studies we investigated whether the perceptual system makes use of this information to infer the presence of a second agent when dealing with impoverished and/or noisy sensory input. Methodology/Principal Findings Participants observed point-light displays of two agents (A and B) performing separate actions. In the Communicative condition, agent B's action was performed in response to a communicative gesture by agent A. In the Individual condition, agent A's communicative action was replaced with a non-communicative action. Participants performed a simultaneous masking yes-no task, in which they were asked to detect the presence of agent B. In Experiment 1, we investigated whether criterion c was lowered in the Communicative condition compared to the Individual condition, thus reflecting a variation in perceptual expectations. In Experiment 2, we manipulated the congruence between A's communicative gesture and B's response, to ascertain whether the lowering of c in the Communicative condition reflected a truly perceptual effect. Results demonstrate that information extracted from communicative gestures influences the concurrent processing of biological motion by prompting perception of a second agent (second-agent effect). Conclusions/Significance We propose that this finding is best explained within a Bayesian framework, which gives a powerful rationale for the pervasive role of prior expectations in visual perception. PMID:21829472

  4. Perspectives on Geospace Plasma Coupling

    SciTech Connect

    Baker, Daniel N.

    2011-01-04

    There are a large variety of fascinating and instructive aspects to examining the coupling of mass and energy from the solar wind into the Earth's magnetosphere. Past research has suggested that magnetic reconnection (in a fluid sense) on the day-side magnetopause plays the key role in controlling the energy coupling. However, both linear and nonlinear coupling processes involving kinetic effects have been suggested through various types of innovative data analysis. Analysis and modeling results have also indicated a prominent role for multi-scale processes of plasma coupling. Examples include evidence of control by solar wind turbulence in the coupling sequence and localized (finite gyroradius) effects in dayside plasma transport. In this paper we describe several solar wind-magnetosphere coupling scenarios. We particularly emphasize the study of solar wind driving of magnetospheric substorm, and related geomagnetic disturbances.

  5. When "together" means "too close": Agency motives and relationship functioning in coresident and living-apart-together couples.

    PubMed

    Hagemeyer, Birk; Schönbrodt, Felix D; Neyer, Franz J; Neberich, Wiebke; Asendorpf, Jens B

    2015-11-01

    The present research addresses the interplay between agency motives and objective dyadic closeness with regard to the functioning of intimate couple relationships. Applying a Person × Situation approach, we hypothesized (a) that partners' implicit and explicit agency motives predict their selection of dyadic living arrangements characterized by high or low objective closeness (coresidence or living-apart-together), (b) that agency motives have more negative effects on relationship functioning in coresident couples, (c) that agency motives predict agentic motivational states in coresident couples, and (d) that agentic states predict day-to-day changes in relationship satisfaction under conditions of high objective closeness. We found support for these between- and within-couple hypotheses in cross-sectional and prospective analyses of an age-heterogeneous sample of 548 heterosexual couples, and in a 2-week diary study with a subsample of 106 couples. Most notably, agentic motive dispositions and motivational states related to relationship functioning more negatively under conditions of high objective closeness. The overall positive effect of objective closeness on relationship functioning was diminished by strong agentic motivation. Perspectives for future research on agency motives in couple relationships are discussed. PMID:26371399

  6. Coupled Planetary Reservoirs

    NASA Astrophysics Data System (ADS)

    Phillips, R. J.

    2008-12-01

    We can look beyond the Earth, to Venus and Mars, to find opportunities to understand interactions among crust, mantle, hydrosphere, and atmosphere reservoirs. There has obviously been coupling among some of these reservoirs on other worlds, and in some cases feedback may have been in play but that is more difficult to demonstrate. The massive CO2 atmosphere of Venus has likely fluctuated significantly over its history due to exchange with other reservoirs, with attendant greenhouse effects strongly modulating surface temperature. Additionally, release of H2O and SO2 from large-scale magmatic events may have led to significant surface temperature increases, ?T0, and the details depend on the competition between IR radiation warming and planetary albedo increase due to cloud formation. Diffusion of ? T0 into the shallow crust may be responsible for the rapid global formation of compressional wrinkle ridges following widespread volcanic resurfacing [Solomon et al., 1999]. Diffusion of ?T0 into the venusian upper mantle could have increased the rate of partial melting. The accompanying increase in volatile release to the atmosphere could set up a positive feedback because of increased greenhouse warming diffusing into the planet's interior [Phillips et al., 2001, Venus]. Another outcome of deep penetration of a greenhouse-induced positive ?T0 is the lowering of mantle viscosity and an accompanying decrease in convective stress, which could shut down an exisiting lithospheric recycling regime [Lenardic et al., 2008]. Mars offers a rich set of possibilities for coupling between reservoirs [Jakosky and Phillips, 2001]. Magmatism at the massive Tharsis volcanic complex possibly induced episodic climate changes in the latter part of the Noachian era (~3.6-4.2 Ga). This could have led to clement conditions, forming valley networks that follow a regional slope caused partly by the mass load of Tharsis itself [Phillips et al., 2001, Mars]. Earlier in the Noachian, lithospheric recycling may have ended as surface temperatures warmed due to planetary outgassing, leading to the Lenardic catastrophe. Outer core convection may have been muted as the mantle heated up, shutting down the martian dynamo [Nimmo and Stevenson, 2000]. In turn, much of the extant atmosphere could have been lost to space, no longer protected from the solar wind by a global magnetic field.

  7. Pulse-coupled BZ oscillators with unequal coupling strengths.

    PubMed

    Horvath, Viktor; Kutner, Daniel J; Chavis, John T; Epstein, Irving R

    2015-02-14

    Coupled chemical oscillators are usually studied with symmetric coupling, either between identical oscillators or between oscillators whose frequencies differ. Asymmetric connectivity is important in neuroscience, where synaptic strength inequality in neural networks commonly occurs. While the properties of the individual oscillators in some coupled chemical systems may be readily changed, enforcing inequality between the connection strengths in a reciprocal coupling is more challenging. We recently demonstrated a novel way of coupling chemical oscillators, which allows for manipulation of individual connection strengths. Here we study two identical, pulse-coupled Belousov-Zhabotinsky (BZ) oscillators with unequal connection strengths. When the pulse perturbations contain KBr (inhibitor), this system exhibits simple out-of-phase and complex oscillations, oscillatory-suppressed states as well as temporally periodic patterns (N : M) in which the two oscillators exhibit different numbers of peaks per cycle. The N : M patterns emerge due to the long-term effect of the inhibitory pulse-perturbations, a feature that has not been considered in earlier works. Time delay was previously shown to have a profound effect on the system's behaviour when pulse coupling was inhibitory and the coupling strengths were equal. When the coupling is asymmetric, however, delay produces no qualitative change in behaviour, though the 1 : 2 temporal pattern becomes more robust. Asymmetry in instantaneous excitatory coupling via AgNO3 injection produces a previously unseen temporal pattern (1 : N patterns starting with a double peak) with time delay and high [AgNO3]. Numerical simulations of the behaviour agree well with theoretical predictions in asymmetrical pulse-coupled systems. PMID:25587932

  8. Self-energized screw coupling

    NASA Technical Reports Server (NTRS)

    Lefever, A. E.; Totah, R. S.

    1980-01-01

    Threaded coupling carries its own store of rotational energy. Originally developed to ease task of astronauts assembling structures in space, coupling offers same advantages in other hazardous operations, such as underwater and in and around nuclear reactors. Coupling consists of two parts: crew portion and receptacle. When screw portion is inserted into receptacle and given slight push by operator, trigger pins release ratchet, allowing energy stored in springs to rotate screw into nut in receptacle.

  9. Cilostazol: an antiplatelet agent for the neurointerventionist?

    PubMed

    Bhogal, P; Brouwer, P A; Makalanda, H L D

    2016-02-01

    Antiplatelet agents are essential for the successful management of patients undergoing a variety of neurointerventional procedures. The most commonly used anti-platelet agents are aspirin, clopidogrel and prasugrel. However, there exist an alternative class of anti-platelet agent that may prove useful for neurointerventionists. In particular a drug called cilostazol may have numerous added advantages above and beyond its antiplatelet effect that may be valuable for our patients. In this short review we aim to highlight some of these potential advantages. PMID:25526917

  10. Knowledge Acquisition Ubiquitous Agent Infrastructure (KAUAI)

    SciTech Connect

    2009-09-15

    Mobile agents are autonomous software programs that can move from one host to another during the course of execution. The KAUAI computer code is a middleware that supports the rapid development and deployment of mobile agent based applications. It is built on the J2ME (CLDC) technology. KAUAI handles the instantiation, execution, transportation, and disposal of mobile agents. KAUAI masks the underlying hardware and communication details from application developers and provides flexible functionality for distributed computing. KAUAI supports software development in systems that involve a large number of heterogeneous computing platforms ranging from workstations to handheld devices.

  11. Resuscitative challenges in nerve agent poisoning.

    PubMed

    Ben Abraham, Ron; Weinbroum, Avi A

    2003-09-01

    The threat of weapons of mass destruction such as nerve agents has become real since last year. The medical community has established protocols for the rapid evacuation and decontamination of affected civilians. However, protocols for resuscitative measures or acute perioperative care in cases of life-saving surgical interventions in toxic-traumatized casualties are still lacking. The database concerning the effects of nerve agent poisoning in humans is limited, and is largely based on reports of unintentional exposures to pesticide organophosphate poisoning and similar chemical substances. In this review, we summarize the knowledge on the possible pharmacological interactions between nerve agents and acute care. PMID:12972890

  12. Pharmacologic agents for mucus clearance in bronchiectasis.

    PubMed

    Nair, Girish B; Ilowite, Jonathan S

    2012-06-01

    There are no approved pharmacologic agents to enhance mucus clearance in non-cystic fibrosis (CF) bronchiectasis. Evidence supports the use of hyperosmolar agents in CF, and studies with inhaled mannitol and hypertonic saline are ongoing in bronchiectasis. N-acetylcysteine may act more as an antioxidant than a mucolytic in other lung diseases. Dornase α is beneficial to patients with CF, but is not useful in patients with non-CF bronchiectasis. Mucokinetic agents such as β-agonists have the potential to improve mucociliary clearance in normals and many disease states, but have not been adequately studied in patients with bronchiectasis. PMID:22640851

  13. Fluorescence quenching of flavins by reductive agents

    NASA Astrophysics Data System (ADS)

    Penzkofer, A.; Bansal, A. K.; Song, S.-H.; Dick, B.

    2007-07-01

    The fluorescence behaviour of the flavins riboflavin, flavin mononucleotide (FMN), flavin adenine dinucleotide (FAD), and lumiflavin in aqueous solution at pH 8 in the presence of the reducing agents ?-mercaptoethanol (?-ME), dithiothreitol (DTT), and sodium nitrite (NaNO 2) is studied under aerobic conditions. The fluorescence quantum yields and fluorescence lifetimes are determined as a function of the reducing agent concentration. For all three reducing agents diffusion controlled dynamic fluorescence quenching is observed which is thought to be due to photo-induced reductive electron transfer. For DTT additionally static fluorescence quenching occurs.

  14. New agents in the treatment of CLL.

    PubMed

    O'Brien, Susan

    2008-01-01

    Chemoimmunotherapy has resulted in high complete remission rates and long remission duration in patients with chronic lymphocytic leukemia (CLL) but relapses occur and curative strategies still need to be developed. A wealth of new agents with a wide variety of mechanisms of action against CLL are currently in clinical trials. Twelve of these agents, which are in various stages of development varying from Phase I to Phase III trials, will be discussed. These include alkylating agents, monoclonal antibodies, immune modulators, cyclin-dependent kinase (CDK) inhibitors, BCL-2 family member inhibitors, protein kinase C (PKC) inhibitors, SRC inhibitors, HSP-90 inhibitors and small modular immune pharmaceutics (SMIP). PMID:19074126

  15. Knowledge Acquisition Ubiquitous Agent Infrastructure (KAUAI)

    Energy Science and Technology Software Center (ESTSC)

    2009-09-15

    Mobile agents are autonomous software programs that can move from one host to another during the course of execution. The KAUAI computer code is a middleware that supports the rapid development and deployment of mobile agent based applications. It is built on the J2ME (CLDC) technology. KAUAI handles the instantiation, execution, transportation, and disposal of mobile agents. KAUAI masks the underlying hardware and communication details from application developers and provides flexible functionality for distributed computing.more » KAUAI supports software development in systems that involve a large number of heterogeneous computing platforms ranging from workstations to handheld devices.« less

  16. Designing Agent Utilities for Coordinated, Scalable and Robust Multi-Agent Systems

    NASA Technical Reports Server (NTRS)

    Tumer, Kagan

    2005-01-01

    Coordinating the behavior of a large number of agents to achieve a system level goal poses unique design challenges. In particular, problems of scaling (number of agents in the thousands to tens of thousands), observability (agents have limited sensing capabilities), and robustness (the agents are unreliable) make it impossible to simply apply methods developed for small multi-agent systems composed of reliable agents. To address these problems, we present an approach based on deriving agent goals that are aligned with the overall system goal, and can be computed using information readily available to the agents. Then, each agent uses a simple reinforcement learning algorithm to pursue its own goals. Because of the way in which those goals are derived, there is no need to use difficult to scale external mechanisms to force collaboration or coordination among the agents, or to ensure that agents actively attempt to appropriate the tasks of agents that suffered failures. To present these results in a concrete setting, we focus on the problem of finding the sub-set of a set of imperfect devices that results in the best aggregate device. This is a large distributed agent coordination problem where each agent (e.g., device) needs to determine whether to be part of the aggregate device. Our results show that the approach proposed in this work provides improvements of over an order of magnitude over both traditional search methods and traditional multi-agent methods. Furthermore, the results show that even in extreme cases of agent failures (i.e., half the agents failed midway through the simulation) the system's performance degrades gracefully and still outperforms a failure-free and centralized search algorithm. The results also show that the gains increase as the size of the system (e.g., number of agents) increases. This latter result is particularly encouraging and suggests that this method is ideally suited for domains where the number of agents is currently in the thousands and will reach tens or hundreds of thousands in the near future.

  17. Cosmological tests of coupled Galileons

    NASA Astrophysics Data System (ADS)

    Brax, Philippe; Burrage, Clare; Davis, Anne-Christine; Gubitosi, Giulia

    2015-03-01

    We investigate the cosmological properties of Galileon models which admit Minkowski space as a stable solution in vacuum. This is motivated by stable, positive tension brane world constructions that give rise to Galileons. We include both conformal and disformal couplings to matter and focus on constraints on the theory that arise because of these couplings. The disformal coupling to baryonic matter is extremely constrained by astrophysical and particle physics effects. The disformal coupling to photons induces a cosmological variation of the speed of light and therefore distorsions of the Cosmic Microwave Background spectrum which are known to be very small. The conformal coupling to baryons leads to a variation of particle masses since Big Bang Nucleosynthesis which is also tightly constrained. We consider the background cosmology of Galileon models coupled to Cold Dark Matter (CDM), photons and baryons and impose that the speed of light and particle masses respect the observational bounds on cosmological time scales. We find that requiring that the equation of state for the Galileon models must be close to -1 now restricts severely their parameter space and can only be achieved with a combination of the conformal and disformal couplings. This leads to large variations of particle masses and the speed of light which are not compatible with observations. As a result, we find that cosmological Galileon models are viable dark energy theories coupled to dark matter but their couplings, both disformal and conformal, to baryons and photons must be heavily suppressed making them only sensitive to CDM.

  18. Spin reorientation via antiferromagnetic coupling

    SciTech Connect

    Ranjbar, M.; Sbiaa, R.; Dumas, R. K.; Åkerman, J.; Piramanayagam, S. N.

    2014-05-07

    Spin reorientation in antiferromagnetically coupled (AFC) Co/Pd multilayers, wherein the thickness of the constituent Co layers was varied, was studied. AFC-Co/Pd multilayers were observed to have perpendicular magnetic anisotropy even for a Co sublayer thickness of 1?nm, much larger than what is usually observed in systems without antiferromagnetic coupling. When similar multilayer structures were prepared without antiferromagnetic coupling, this effect was not observed. The results indicate that the additional anisotropy energy contribution arising from the antiferromagnetic coupling, which is estimated to be around 6?×?10{sup 6}?ergs/cm{sup 3}, induces the spin-reorientation.

  19. Semiclassical Coupled Channels Theory

    NASA Astrophysics Data System (ADS)

    Grawert, G.; Müller, St.

    A semiclassical theory for heavy ion scattering in the Fresnel diffraction regime covering coupled elastic and inelastic channels is developed. The scattering is described as diffraction off the rainbow trajectory along which the development of the internal degrees of freedom is calculated. Simple formulae for the transition amplitudes are derived and interpreted in terms of matching conditions, time scales and potential strengths at closest approach. Polarization potentials comprising of real and absorptive terms and of tensors of various ranks are constructed. Analyzing power data for elastic and inelastic scattering of polarized 7Li on 120Sn are analyzed.Translated AbstractSemiklassische Theorie gekoppelter KanäleEine semiklassische Theorie für die Streuung von Schwerionen wird entwickelt, die elastische und inelastische Streuung im Bereich der Fresnel-Beugung beschreibt. Der Streuprozeß wird als Beugung von der Regenbogen-Trajektorie weg verstanden, und entlang dieser Bahn wird die zeitliche Entwicklung der inneren Freiheitsgrade berechnet. Einfache analytische Formeln für die Übergangsamplituden werden abgeleitet und mit Hilfe von Anpassungs-(Matching-) Bedingungen, Zeitskalen und Potentialstärken am Punkt nächster Annäherung interpretiert. Polarisationspotentiale werden konstruiert, die sowohl reelle als auch absorptive Anteile und Tensorterme verschiedener Stufen enthalten. Experimentelle Daten für die Analysierstärken für elastische und inelastische Streuung von polarisiertem 7Li an 120Sn werden theoretisch analysiert.

  20. Coupled plasma filtration adsorption.

    PubMed

    Formica, Marco; Inguaggiato, Paola; Bainotti, Serena; Wratten, Mary Lou

    2007-01-01

    Sepsis is one of the main causes of death in critically ill patients worldwide, and in many cases it is associated with renal and/or other organ failure. However, we do not have a unique efficient therapy to reduce this extremely high mortality rate. In the last years interest around the use of extracorporeal blood purification techniques has increased. One of the emerging treatments in patients with severe sepsis and septic shock is coupled plasma filtration adsorption (CPFA), a novel extracorporeal blood purification therapy aimed at a nonselective reduction of the circulating levels and activities of both pro- and anti-inflammatory mediators. Early experimental studies and the following clinical trials have demonstrated impressive results regarding hemodynamics and respiratory parameters, even in patients without concomitant acute renal injury, paralleled by a quick tapering of vasoactive drugs. Considering the still high morbidity and mortality rates in septic shock patients, this new blood purification technique seems to have benefits when applied early in the course of sepsis, also without renal indications, suggesting that it might be performed to prevent rather than to treat acute kidney injury. PMID:17464151