Sample records for excess negative charge

  1. Electromagnetic Radiation in the Atmosphere Generated by Excess Negative Charge in a Nuclear-Electromagnetic Cascade

    NASA Astrophysics Data System (ADS)

    Malyshevsky, V. S.; Fomin, G. V.

    2017-01-01

    On the basis of the analytical model "PARMA" (PHITS-based Analytical Radiation Model in the Atmosphere), developed to model particle fluxes of secondary cosmic radiation in the Earth's atmosphere, we have calculated the characteristics of radio waves emitted by excess negative charge in an electromagnetic cascade. The results may be of use in an analysis of experimental data on radio emission of electron-photon showers in the atmosphere.

  2. Charge Effects on the Efflorescence in Single Levitated Droplets.

    PubMed

    Hermann, Gunter; Zhang, Yan; Wassermann, Bernhard; Fischer, Henry; Quennet, Marcel; Rühl, Eckart

    2017-09-14

    The influence of electrical excess charges on the crystallization from supersaturated aqueous sodium chloride solutions is reported. This is accomplished by efflorescence studies on single levitated microdroplets using optical and electrodynamic levitation. Specifically, a strong increase in efflorescence humidity is observed as a function of the droplet's negative excess charge, ranging up to -2.1 pC, with a distinct threshold behavior, increasing the relative efflorescence humidity, at which spontaneous nucleation occurs, from 44% for the neutral microparticle to 60%. These findings are interpreted by using molecular dynamics simulations for determining plausible structural patterns located near the particle surface that could serve as suitable precursors for the formation of critical clusters overcoming the nucleation barrier. These results, facilitating heterogeneous nucleation in the case of negatively charged microparticles, are compared to recent work on charge-induced nucleation of neat supercooled water, where a distinctly different nucleation behavior as a function of droplet charge has been observed.

  3. Second harmonic generation study of malachite green adsorption at the interface between air and an electrolyte solution: observing the effect of excess electrical charge density at the interface.

    PubMed

    Song, Jinsuk; Kim, Mahn Won

    2010-03-11

    Understanding the differential adsorption of ions at the interface of an electrolyte solution is very important because it is closely related, not only to the fundamental aspects of biological systems, but also to many industrial applications. We have measured the excess interfacial negative charge density at air-electrolyte solution interfaces by using resonant second harmonic generation of oppositely charged probe molecules. The excess charge density increased with the square root of the bulk electrolyte concentration. A new adsorption model that includes the electrostatic interaction between adsorbed molecules is proposed to explain the measured adsorption isotherm, and it is in good agreement with the experimental results.

  4. The Origins of Positive and Negative in Electricity

    ERIC Educational Resources Information Center

    Jensen, William B.

    2005-01-01

    Benjamin Franklin first introduced the terms positive and negative into electrical theory in the year 1747. The positive and negative terms originally had nothing to do with inherent electrical charge, but rather indicated which object had an excess of electrical fluid indicating positive, and which had a deficiency, indicating negative.

  5. An analysis of five negative sprite-parent discharges and their associated thunderstorm charge structures

    NASA Astrophysics Data System (ADS)

    Boggs, Levi D.; Liu, Ningyu; Splitt, Michael; Lazarus, Steven; Glenn, Chad; Rassoul, Hamid; Cummer, Steven A.

    2016-01-01

    In this study we analyze the discharge morphologies of five confirmed negative sprite-parent discharges and the associated charge structures of the thunderstorms that produced them. The negative sprite-parent lightning took place in two thunderstorms that were associated with a tropical disturbance in east central and south Florida. The first thunderstorm, which moved onshore in east central Florida, produced four of the five negative sprite-parent discharges within a period of 17 min, as it made landfall from the Atlantic Ocean. These negative sprite-parents were composed of bolt-from-the-blue (BFB), hybrid intracloud-negative cloud-to-ground (IC-NCG), and multicell IC-NCGs discharges. The second thunderstorm, which occurred inland over south Florida, produced a negative sprite-parent that was a probable hybrid IC-NCG discharge and two negative gigantic jets (GJs). Weakened upper positive charge with very large midlevel negative charge was inferred for both convective cells that initiated the negative-sprite-parent discharges. Our study suggests tall, intense convective systems with high wind shear at the middle to upper regions of the cloud accompanied by low cloud-to-ground (CG) flash rates promote these charge structures. The excess amount of midlevel negative charge results in these CG discharges transferring much more charge to ground than typical negative CG discharges. We find that BFB discharges prefer an asymmetrical charge structure that brings the negative leader exiting the upper positive charge region closer to the lateral positive screening charge layer. This may be the main factor in determining whether a negative leader exiting the upper positive region of the thundercloud forms a BFB or GJ.

  6. On energetic prerequisites of attracting electrons

    NASA Astrophysics Data System (ADS)

    Sundholm, Dage

    2014-06-01

    The internal reorganization energy and the zero-point vibrational energy (ZPE) of fractionally charged molecules embedded in molecular materials are discussed. The theory for isolated open quantum systems is taken as the starting point. It is shown that for isolated molecules the internal reorganization-energy function and its slope, i.e., the chemical potential of an open molecular system are monotonically decreasing functions with respect to increasing amount of negative excess charge (q) in the range of q = [0, 1]. Calculations of the ZPE for fractionally charged molecules show that the ZPE may have a minimum for fractional occupation. The calculations show that the internal reorganization energy and changes in the ZPE are of the same order of magnitude with different behavior as a function of the excess charge. The sum of the contributions might favor molecules with fractional occupation of the molecular units and partial delocalization of the excess electrons in solid-state materials also when considering Coulomb repulsion between the excess electrons. The fractional electrons are then coherently distributed on many molecules of the solid-state material forming a condensate of attracting electrons, which is crucial for the superconducting state.

  7. On energetic prerequisites of attracting electrons.

    PubMed

    Sundholm, Dage

    2014-06-21

    The internal reorganization energy and the zero-point vibrational energy (ZPE) of fractionally charged molecules embedded in molecular materials are discussed. The theory for isolated open quantum systems is taken as the starting point. It is shown that for isolated molecules the internal reorganization-energy function and its slope, i.e., the chemical potential of an open molecular system are monotonically decreasing functions with respect to increasing amount of negative excess charge (q) in the range of q = [0, 1]. Calculations of the ZPE for fractionally charged molecules show that the ZPE may have a minimum for fractional occupation. The calculations show that the internal reorganization energy and changes in the ZPE are of the same order of magnitude with different behavior as a function of the excess charge. The sum of the contributions might favor molecules with fractional occupation of the molecular units and partial delocalization of the excess electrons in solid-state materials also when considering Coulomb repulsion between the excess electrons. The fractional electrons are then coherently distributed on many molecules of the solid-state material forming a condensate of attracting electrons, which is crucial for the superconducting state.

  8. Effect of plasma-induced surface charging on catalytic processes: application to CO2 activation

    NASA Astrophysics Data System (ADS)

    Bal, Kristof M.; Huygh, Stijn; Bogaerts, Annemie; Neyts, Erik C.

    2018-02-01

    Understanding the nature and effect of the multitude of plasma-surface interactions in plasma catalysis is a crucial requirement for further process development and improvement. A particularly intriguing and rather unique property of a plasma-catalytic setup is the ability of the plasma to modify the electronic structure, and hence chemical properties, of the catalyst through charging, i.e. the absorption of excess electrons. In this work, we develop a quantum chemical model based on density functional theory to study excess negative surface charges in a heterogeneous catalyst exposed to a plasma. This method is specifically applied to investigate plasma-catalytic CO2 activation on supported M/Al2O3 (M = Ti, Ni, Cu) single atom catalysts. We find that (1) the presence of a negative surface charge dramatically improves the reductive power of the catalyst, strongly promoting the splitting of CO2 to CO and oxygen, and (2) the relative activity of the investigated transition metals is also changed upon charging, suggesting that controlled surface charging is a powerful additional parameter to tune catalyst activity and selectivity. These results strongly point to plasma-induced surface charging of the catalyst as an important factor contributing to the plasma-catalyst synergistic effects frequently reported for plasma catalysis.

  9. Hydration of excess electrons trapped in charge pockets on molecular surfaces

    NASA Astrophysics Data System (ADS)

    Jalbout, Abraham F.; Del Castillo, R.; Adamowicz, Ludwik

    2007-01-01

    In this work we strive to design a novel electron trap located on a molecular surface. The process of electron trapping involves hydration of the trapped electron. Previous calculations on surface electron trapping revealed that clusters of OH groups can form stable hydrogen-bonded networks on one side of a hydrocarbon surface (i.e. cyclohexane sheets), while the hydrogen atoms on the opposite side of the surface form pockets of positive charge that can attract extra negative charge. The excess electron density on such surfaces can be further stabilized by interactions with water molecules. Our calculations show that these anionic systems are stable with respect to vertical electron detachment (VDE).

  10. An investigation of the generation and properties of laboratory-produced ball lightning

    NASA Astrophysics Data System (ADS)

    Oreshko, A. G.

    2015-06-01

    The experiments revealed that ball lightning is a self-confining quasi-neutral in a whole plasma system that rotates around its axis. Ball lightning has a structure of a spherical electric domain, consisting of a kernel with excess negative charge and an external spherical layer with excess positive charge. The excess of charges of one sort and the lack of charges of the other sort in the kernel or in the external spherical layer significantly reduces the possibility of electron capture by means of an electric field, created by the nearest ions and leads to a drastic slowdown of recombination process. Direct proof has been obtained that inside of ball lightning - in an external spherical layer that rotates around the axis - there is a circular current of sub-relativistic particles. This current creates and maintains its own poloidal magnetic field of ball lightning, i.e. it carries out the function of magnetic dynamo. The kernel of ball lightning is situated in a region with minimum values of induction of the magnetic field. The inequality of positive and negative charges in elements of ball lightning also significantly reduces losses of the charged plasma on bremsstrahlung. Ball lightning generation occurs in a plasmic vortex. The ball lightning energy in the region of its generation significantly differs from the ball lightning energy, which is drifting in space. The axial component of kinetic energy of particles slightly exceeds 100 keV and the rotational component of the ions energy is a bit greater than 1 MeV. Ball lightning is `embedded' in atmosphere autonomous accelerator of charged particles of a cyclotron type due to self-generation of strong crossed electric and magnetic fields. A discussion of the conditions of stability and long-term existence of ball lightning is given.

  11. On energetic prerequisites of attracting electrons

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Sundholm, Dage

    The internal reorganization energy and the zero-point vibrational energy (ZPE) of fractionally charged molecules embedded in molecular materials are discussed. The theory for isolated open quantum systems is taken as the starting point. It is shown that for isolated molecules the internal reorganization-energy function and its slope, i.e., the chemical potential of an open molecular system are monotonically decreasing functions with respect to increasing amount of negative excess charge (q) in the range of q = [0, 1]. Calculations of the ZPE for fractionally charged molecules show that the ZPE may have a minimum for fractional occupation. The calculations showmore » that the internal reorganization energy and changes in the ZPE are of the same order of magnitude with different behavior as a function of the excess charge. The sum of the contributions might favor molecules with fractional occupation of the molecular units and partial delocalization of the excess electrons in solid-state materials also when considering Coulomb repulsion between the excess electrons. The fractional electrons are then coherently distributed on many molecules of the solid-state material forming a condensate of attracting electrons, which is crucial for the superconducting state.« less

  12. Development of a ferromagnetic component in the superconducting state of Fe-excess Fe1.12Te1-xSex by electronic charge redistribution

    NASA Astrophysics Data System (ADS)

    Li, Wen-Hsien; Karna, Sunil K.; Hsu, Han; Li, Chi-Yen; Lee, Chi-Hung; Sankar, Raman; Cheng Chou, Fang

    2015-06-01

    The general picture established so far for the links between superconductivity and magnetic ordering in iron chalcogenide Fe1+y(Te1-xSex) is that the substitution of Se for Te directly drives the system from the antiferromagnetic end into the superconducting regime. Here, we report on the observation of a ferromagnetic component that developed together with the superconducting transition in Fe-excess Fe1.12Te1-xSex crystals using neutron and x-ray diffractions, resistivity, magnetic susceptibility and magnetization measurements. The superconducting transition is accompanied by a negative thermal expansion of the crystalline unit cell and an electronic charge redistribution, where a small portion of the electronic charge flows from around the Fe sites toward the Te/Se sites. First-principles calculations show consistent results, revealing that the excess Fe ions play a more significant role in affecting the magnetic property in the superconducting state than in the normal state and the occurrence of an electronic charge redistribution through the superconducting transition.

  13. An Analysis of Two Thunderstorms Producing Five Negative Sprites on 12 September 2014

    NASA Astrophysics Data System (ADS)

    Boggs, L.; Liu, N.; Splitt, M. E.; Lazarus, S. M.; Cummer, S. A.; Rassoul, H.

    2015-12-01

    We present a detailed analysis of the thunderstorms and the parent lightning discharge morphologies of five confirmed negative sprites taking place in two different thunderstorms. These two thunderstorms took place in east-central and south Florida on 12 September 2014. We utilized several lightning location networks, remote magnetic field measurements, dual polarization radar, and balloon borne soundings in our analysis. Each parent discharge was immediately preceded by intra-cloud (IC) discharges between the mid-level negative and upper positive charge regions. This either allowed a second upward negative leader to escape the upper positive charge region, or encouraged a downward negative leader to be initiated and connect with ground. The discharges found in this study support the findings of Lu et al., 2012 [JGR,117, D04212, 2012] that negative sprite-parent lightning consists primarily of hybrid intra-cloud negative cloud-to-ground (IC-NCG) and bolt-from-the-blue (BFB) lightning. Our work finds these unique discharges form in thunderstorms that have an excess of mid-level negative charge and weakened upper positive charge. Due to this charge structure, these unusual discharges transfer more charge to the ground than typical negative cloud-to-ground discharges. Our study suggests that the key difference separating bolt-from-the-blue and gigantic jet discharges is an asymmetric charge structure. This acts to bring the negative leader exiting the thundercloud closer to the lateral positive screening layer, encouraging the negative leader to turn towards ground. This investigation reveals IC discharges that involve multiple convective cells and come to ground as a negative CG discharge, a breed of hybrid IC-NCG discharges, also transfer more negative charge to ground than typical negative CG discharges and are able to initiate negative sprites. From this work, the charge structures mentioned above resulted from tall, intense convective cells with low CG flash rates with high wind shear in the mid to upper regions of the cloud. This acted to create a large reservoir of mid-level negative charge and create a general asymmetry to the charge structure. The wind shear in the upper regions also acted to weaken the upper positive charge by turbulent mixing with the upper negative screening charge layer.

  14. The impact of hot charge carrier mobility on photocurrent losses in polymer-based solar cells

    PubMed Central

    Philippa, Bronson; Stolterfoht, Martin; Burn, Paul L.; Juška, Gytis; Meredith, Paul; White, Ronald D.; Pivrikas, Almantas

    2014-01-01

    A typical signature of charge extraction in disordered organic systems is dispersive transport, which implies a distribution of charge carrier mobilities that negatively impact on device performance. Dispersive transport has been commonly understood to originate from a time-dependent mobility of hot charge carriers that reduces as excess energy is lost during relaxation in the density of states. In contrast, we show via photon energy, electric field and film thickness independence of carrier mobilities that the dispersive photocurrent in organic solar cells originates not from the loss of excess energy during hot carrier thermalization, but rather from the loss of carrier density to trap states during transport. Our results emphasize that further efforts should be directed to minimizing the density of trap states, rather than controlling energetic relaxation of hot carriers within the density of states. PMID:25047086

  15. Electrostatic theory of the assembly of PAMAM dendrimers and DNA.

    PubMed

    Perico, Angelo

    2016-05-01

    The electrostatic interactions mediated by counterions between a cationic PAMAM dendrimer, modelized as a sphere of radius and cationic surface charge highly increasing with generation, and a DNA, modelized as an anionic elastic line, are analytically calculated in the framework of condensation theory. Under these interactions the DNA is wrapped around the sphere. For excess phosphates relative to dendrimer primary amines, the free energy of the DNA-dendrimer complex displays an absolute minimum when the complex is weakly negatively overcharged. This overcharging opposes gene delivery. For a highly positive dendrimer and a DNA fixed by experimental conditions to a number of phosphates less than the number of dendrimer primary amines, excess amine charges, the dendrimer may at the same time bind stably DNA and interact with negative cell membranes to activate cell transfection in fair agreement with molecular simulations and experiments. © 2016 Wiley Periodicals, Inc.

  16. Triboelectricity: macroscopic charge patterns formed by self-arraying ions on polymer surfaces.

    PubMed

    Burgo, Thiago A L; Ducati, Telma R D; Francisco, Kelly R; Clinckspoor, Karl J; Galembeck, Fernando; Galembeck, Sergio E

    2012-05-15

    Tribocharged polymers display macroscopically patterned positive and negative domains, verifying the fractal geometry of electrostatic mosaics previously detected by electric probe microscopy. Excess charge on contacting polyethylene (PE) and polytetrafluoroethylene (PTFE) follows the triboelectric series but with one caveat: net charge is the arithmetic sum of patterned positive and negative charges, as opposed to the usual assumption of uniform but opposite signal charging on each surface. Extraction with n-hexane preferentially removes positive charges from PTFE, while 1,1-difluoroethane and ethanol largely remove both positive and negative charges. Using suitable analytical techniques (electron energy-loss spectral imaging, infrared microspectrophotometry and carbonization/colorimetry) and theoretical calculations, the positive species were identified as hydrocarbocations and the negative species were identified as fluorocarbanions. A comprehensive model is presented for PTFE tribocharging with PE: mechanochemical chain homolytic rupture is followed by electron transfer from hydrocarbon free radicals to the more electronegative fluorocarbon radicals. Polymer ions self-assemble according to Flory-Huggins theory, thus forming the experimentally observed macroscopic patterns. These results show that tribocharging can only be understood by considering the complex chemical events triggered by mechanical action, coupled to well-established physicochemical concepts. Patterned polymers can be cut and mounted to make macroscopic electrets and multipoles.

  17. Polyelectrolyte-assisted preparation of gold nanocluster-doped silica particles with high incorporation efficiency and improved stability

    NASA Astrophysics Data System (ADS)

    Wang, Haonan; Huang, Zhenzhen; Guo, Zilong; Yang, Wensheng

    2017-07-01

    In this paper, we reported an approach for efficient incorporation of glutathione-capped gold nanoclusters (GSH-Au NCs) into silica particles with the assistance of a polyelectrolyte, poly-diallyldimethyl-ammoniumchloride (PDDA). In this approach, the negatively charged GSH-Au NCs were firstly mixed with the positively charged PDDA to form PDDA-Au NC complexes. Then, the complexes were added into a pre-hydrolyzed Stöber system to get the Au NCs-doped silica particles. With increased ratio of PDDA in the complexes, the negative charges on surface of the Au NCs were neutralized gradually and finally reversed to positive in presence of excess PDDA, which facilitated the incorporation of the Au NCs into the negatively charged silica matrix. Under the optimal amount of PDDA in the complexes, the incorporation efficiency of Au NCs could be as high as 88%. After being incorporated into the silica matrix, the Au NCs become much robust against pH and heavy metal ions attributed to the protection effect of silica and PDDA. This approach was also extendable to highly efficient incorporation of other negatively charged metal nanoclusters, such as bovine serum albumin-capped Cu nanoclusters, into silica matrix.

  18. The effect of surface charge, negative and bipolar ionization on the deposition of airborne bacteria.

    PubMed

    Meschke, S; Smith, B D; Yost, M; Miksch, R R; Gefter, P; Gehlke, S; Halpin, H A

    2009-04-01

    A series of experiments were conducted to evaluate the effect of surface charge and air ionization on the deposition of airborne bacteria. The interaction between surface electrostatic potential and the deposition of airborne bacteria in an indoor environment was investigated using settle plates charged with electric potentials of 0, +/-2.5kV and +/-5kV. Results showed that bacterial deposition on the plates increased proportionally with increased potential to over twice the gravitational sedimentation rate at +5kV. Experiments were repeated under similar conditions in the presence of either negative or bipolar air ionization. Bipolar air ionization resulted in reduction of bacterial deposition onto the charged surfaces to levels nearly equal to gravitational sedimentation. In contrast, diffusion charging appears to have occurred during negative air ionization, resulting in an even greater deposition onto the oppositely charged surface than observed without ionization. Static charges on fomitic surfaces may attract bacteria resulting in deposition in excess of that expected by gravitational sedimentation or simple diffusion. Implementation of bipolar ionization may result in reduction of bacterial deposition. Fomitic surfaces are important vehicles for the transmission of infectious organisms. This study has demonstrated a simple strategy for minimizing charge related deposition of bacteria on surfaces.

  19. Polymer nanocomposites for lithium battery applications

    DOEpatents

    Sandi-Tapia, Giselle; Gregar, Kathleen Carrado

    2006-07-18

    A single ion-conducting nanocomposite of a substantially amorphous polyethylene ether and a negatively charged synthetic smectite clay useful as an electrolyte. Excess SiO2 improves conductivity and when combined with synthetic hectorite forms superior membranes for batteries. A method of making membranes is also disclosed.

  20. Electrolyte effects in a model of proton discharge on charged electrodes

    NASA Astrophysics Data System (ADS)

    Wiebe, Johannes; Kravchenko, Kateryna; Spohr, Eckhard

    2015-01-01

    We report results on the influence of NaCl electrolyte dissolved in water on proton discharge reactions from aqueous solution to charged platinum electrodes. We have extended a recently developed combined proton transfer/proton discharge model on the basis of empirical valence bond theory to include NaCl solutions with several different concentrations of cations and anions, both stoichiometric (1:1) compositions and non-stoichiometric ones with an excess of cations. The latter solutions partially screen the electrostatic potential from the surface charge of the negatively charged electrode. 500-1000 trajectories of a discharging proton were integrated by molecular dynamics simulations until discharge occurred, or for at most 1.5 ns. The results show a strong dependence on ionic strength, but only a weak dependence on the screening behavior, when comparing stoichiometric and non-stoichiometric solutions. Overall, the Na+ cations exert a more dominant effect on the discharge reaction, which we argue is likely due to the very rigid arrangements of the cations on the negatively polarized electrode surface. Thus, our model predicts, for the given and very high negative surface charge densities, the fastest discharge reaction for pure water, but obviously cannot take into account the fact that such high charge densities are even more out of reach experimentally than for higher electrolyte concentrations.

  1. Superposition Principle in Auger Recombination of Charged and Neutral Multicarrier States in Semiconductor Quantum Dots

    DOE PAGES

    Wu, Kaifeng; Lim, Jaehoon; Klimov, Victor I.

    2017-07-19

    Application of colloidal semiconductor quantum dots (QDs) in optical and optoelectronic devices is often complicated by unintentional generation of extra charges, which opens fast nonradiative Auger recombination pathways whereby the recombination energy of an exciton is quickly transferred to the extra carrier(s) and ultimately dissipated as heat. Previous studies of Auger recombination have primarily focused on neutral and, more recently, negatively charged multicarrier states. Auger dynamics of positively charged species remains more poorly explored due to difficulties in creating, stabilizing, and detecting excess holes in the QDs. Here we apply photochemical doping to prepare both negatively and positively charged CdSe/CdSmore » QDs with two distinct core/shell interfacial profiles (“sharp” versus “smooth”). Using neutral and charged QD samples we evaluate Auger lifetimes of biexcitons, negative and positive trions (an exciton with an extra electron or a hole, respectively), and multiply negatively charged excitons. Using these measurements, we demonstrate that Auger decay of both neutral and charged multicarrier states can be presented as a superposition of independent elementary three-particle Auger events. As one of the manifestations of the superposition principle, we observe that the biexciton Auger decay rate can be presented as a sum of the Auger rates for independent negative and positive trion pathways. Furthermore, by comparing the measurements on the QDs with the “sharp” versus “smooth” interfaces, we also find that while affecting the absolute values of Auger lifetimes, manipulation of the shape of the confinement potential does not lead to violation of the superposition principle, which still allows us to accurately predict the biexciton Auger lifetimes based on the measured negative and positive trion dynamics. Our findings indicate considerable robustness of the superposition principle as applied to Auger decay of charged and neutral multicarrier states, suggesting its generality to quantum-confined nanocrystals of arbitrary compositions and complexities.« less

  2. Superposition Principle in Auger Recombination of Charged and Neutral Multicarrier States in Semiconductor Quantum Dots.

    PubMed

    Wu, Kaifeng; Lim, Jaehoon; Klimov, Victor I

    2017-08-22

    Application of colloidal semiconductor quantum dots (QDs) in optical and optoelectronic devices is often complicated by unintentional generation of extra charges, which opens fast nonradiative Auger recombination pathways whereby the recombination energy of an exciton is quickly transferred to the extra carrier(s) and ultimately dissipated as heat. Previous studies of Auger recombination have primarily focused on neutral and, more recently, negatively charged multicarrier states. Auger dynamics of positively charged species remains more poorly explored due to difficulties in creating, stabilizing, and detecting excess holes in the QDs. Here we apply photochemical doping to prepare both negatively and positively charged CdSe/CdS QDs with two distinct core/shell interfacial profiles ("sharp" versus "smooth"). Using neutral and charged QD samples we evaluate Auger lifetimes of biexcitons, negative and positive trions (an exciton with an extra electron or a hole, respectively), and multiply negatively charged excitons. Using these measurements, we demonstrate that Auger decay of both neutral and charged multicarrier states can be presented as a superposition of independent elementary three-particle Auger events. As one of the manifestations of the superposition principle, we observe that the biexciton Auger decay rate can be presented as a sum of the Auger rates for independent negative and positive trion pathways. By comparing the measurements on the QDs with the "sharp" versus "smooth" interfaces, we also find that while affecting the absolute values of Auger lifetimes, manipulation of the shape of the confinement potential does not lead to violation of the superposition principle, which still allows us to accurately predict the biexciton Auger lifetimes based on the measured negative and positive trion dynamics. These findings indicate considerable robustness of the superposition principle as applied to Auger decay of charged and neutral multicarrier states, suggesting its generality to quantum-confined nanocrystals of arbitrary compositions and complexities.

  3. Overcharge tolerant high-temperature cells and batteries

    DOEpatents

    Redey, Laszlo; Nelson, Paul A.

    1989-01-01

    In a lithium-alloy/metal sulfide high temperature electrochemical cell, cell damage caused by overcharging is avoided by providing excess lithium in a high-lithium solubility phase alloy in the negative electrode and a specified ratio maximum of the capacity of a matrix metal of the negative electrode in the working phase to the capacity of a transition metal of the positive electrode. In charging the cell, or a plurality of such cells in series and/or parallel, chemical transfer of elemental lithium from the negative electrode through the electrolyte to the positive electrode provides sufficient lithium to support an increased self-charge current to avoid anodic dissolution of the positive electrode components above a critical potential. The lithium is subsequently electrochemically transferred back to the negative electrode in an electrochemical/chemical cycle which maintains high self-discharge currents on the order of 3-15 mA/cm.sup.2 in the cell to prevent overcharging.

  4. Towards biocompatible vaccine delivery systems: interactions of colloidal PECs based on polysaccharides with HIV-1 p24 antigen.

    PubMed

    Drogoz, Alexandre; Munier, Séverine; Verrier, Bernard; David, Laurent; Domard, Alain; Delair, Thierry

    2008-02-01

    This work reports on the interactions of a model protein (p24, the capside protein of HIV-1 virus) with colloids obtained from polyelectrolyte complexes (PECs) involving two polysaccharides: chitosan and dextran sulfate (DS). The PECs were elaborated by a one-shot addition of default amounts of one counterpart to the polymer in excess. Depending on the nature of the excess polyelectrolyte, the submicrometric colloid was either positively or negatively charged. HIV-1 capsid p24 protein was chosen as antigen, the ultrapure form, lipopolysaccharide-free (endotoxin-, vaccine grade) was used in most experiments, as the level of purity of the protein had a great impact on the immobilization process. p24 sorption kinetics, isotherms, and loading capacities were investigated for positively and negatively charged particles of chitosans and dextran sulfates differing in degrees of polymerization (DP) or acetylation (DA). Compared with the positive particles, negatively charged colloids had higher binding capacities, faster kinetics, and a better stability of the adsorbed p24. Capacities up to 600 mg x g(-1) (protein-colloid) were obtained, suggesting that the protein interacted within the shell of the particles. Small-angle X-rays scattering experiments confirmed this hypothesis. Finally, the immunogenicity of the p24-covered particles was assessed for vaccine purposes in mice. The antibody titers obtained with immobilized p24 was dose dependent and in the same range as for Freund's adjuvant, a gold standard for humoral responses.

  5. DOE Office of Scientific and Technical Information (OSTI.GOV)

    Wu, Kaifeng; Lim, Jaehoon; Klimov, Victor I.

    Application of colloidal semiconductor quantum dots (QDs) in optical and optoelectronic devices is often complicated by unintentional generation of extra charges, which opens fast nonradiative Auger recombination pathways whereby the recombination energy of an exciton is quickly transferred to the extra carrier(s) and ultimately dissipated as heat. Previous studies of Auger recombination have primarily focused on neutral and, more recently, negatively charged multicarrier states. Auger dynamics of positively charged species remains more poorly explored due to difficulties in creating, stabilizing, and detecting excess holes in the QDs. Here we apply photochemical doping to prepare both negatively and positively charged CdSe/CdSmore » QDs with two distinct core/shell interfacial profiles (“sharp” versus “smooth”). Using neutral and charged QD samples we evaluate Auger lifetimes of biexcitons, negative and positive trions (an exciton with an extra electron or a hole, respectively), and multiply negatively charged excitons. Using these measurements, we demonstrate that Auger decay of both neutral and charged multicarrier states can be presented as a superposition of independent elementary three-particle Auger events. As one of the manifestations of the superposition principle, we observe that the biexciton Auger decay rate can be presented as a sum of the Auger rates for independent negative and positive trion pathways. Furthermore, by comparing the measurements on the QDs with the “sharp” versus “smooth” interfaces, we also find that while affecting the absolute values of Auger lifetimes, manipulation of the shape of the confinement potential does not lead to violation of the superposition principle, which still allows us to accurately predict the biexciton Auger lifetimes based on the measured negative and positive trion dynamics. Our findings indicate considerable robustness of the superposition principle as applied to Auger decay of charged and neutral multicarrier states, suggesting its generality to quantum-confined nanocrystals of arbitrary compositions and complexities.« less

  6. Simple Pencil-and-Paper Notation for Representing Electrical Charge States

    ERIC Educational Resources Information Center

    Morse, Robert A.

    2017-01-01

    In Benjamin Franklin's one fluid theory of electrification, ordinary unelectrified matter consisted of a matrix of matter suffused with a certain amount of "electrical fluid." Electrical effects were due to an excess or deficit of electrical fluid, hence the terms positive and negative. Before the development of a modern view of the…

  7. Fluorescence spectral shift of QD films with electron injection: Dependence on counterion proximity

    NASA Astrophysics Data System (ADS)

    Lu, Meilin; Li, Bo; Zhang, Yaxin; Liu, Weilong; Yang, Yanqiang; Wang, Yuxiao; Yang, Qingxin

    2017-05-01

    Due to the promising application of quantum dot (QD) films in solar cells, LEDs and environmental detectors, the fluorescence of charged QD films has achieved much attention during recent years. In this work, we observe the spectral shift of photoluminescence (PL) in charged CdSe/ZnS QD films controlled by electrochemical potential. The spectral center under negative bias changes from red-shift to blue-shift while introducing smaller inorganic counterions (potassium ions) into the electrolyte. This repeatable effect is attributed to the enhanced electron injection with smaller cations and the electronic perturbations of QD luminescence by these excess charges.

  8. Method of preparing an electrochemical cell in uncharged state

    DOEpatents

    Shimotake, Hiroshi; Bartholme, Louis G.; Arntzen, John D.

    1977-02-01

    A secondary electrochemical cell is assembled in an uncharged state for the preparation of a lithium alloy-transition metal sulfide cell. The negative electrode includes a material such as aluminum or silicon for alloying with lithium as the cell is charged. The positive electrode is prepared by blending particulate lithium sulfide, transition metal powder and electrolytic salt in solid phase. The mixture is simultaneously heated to a temperature in excess of the melting point of the electrolyte and pressed onto an electrically conductive substrate to form a plaque. The plaque is assembled as a positive electrode within the cell. During the first charge cycle lithium alloy is formed within the negative electrode and transition metal sulfide such as iron sulfide is produced within the positive electrode.

  9. 24 CFR 966.4 - Lease requirements.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... charges to the tenant for maintenance and repair beyond normal wear and tear and for consumption of excess... of charges for repair, amounts charged for utility consumption in excess of the allowance stated in the lease, etc.). The imposition of charges for consumption of excess utilities is permissible only if...

  10. 24 CFR 966.4 - Lease requirements.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... charges to the tenant for maintenance and repair beyond normal wear and tear and for consumption of excess... of charges for repair, amounts charged for utility consumption in excess of the allowance stated in the lease, etc.). The imposition of charges for consumption of excess utilities is permissible only if...

  11. 24 CFR 966.4 - Lease requirements.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... charges to the tenant for maintenance and repair beyond normal wear and tear and for consumption of excess... of charges for repair, amounts charged for utility consumption in excess of the allowance stated in the lease, etc.). The imposition of charges for consumption of excess utilities is permissible only if...

  12. 24 CFR 966.4 - Lease requirements.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... charges to the tenant for maintenance and repair beyond normal wear and tear and for consumption of excess... of charges for repair, amounts charged for utility consumption in excess of the allowance stated in the lease, etc.). The imposition of charges for consumption of excess utilities is permissible only if...

  13. A combined rocket-borne and ground-based study of the sodium layer and charged dust in the upper mesosphere

    NASA Astrophysics Data System (ADS)

    Plane, John M. C.; Saunders, Russell W.; Hedin, Jonas; Stegman, Jacek; Khaplanov, Misha; Gumbel, Jörg; Lynch, Kristina A.; Bracikowski, Phillip J.; Gelinas, Lynette J.; Friedrich, Martin; Blindheim, Sandra; Gausa, Michael; Williams, Bifford P.

    2014-10-01

    The Hotel Payload 2 rocket was launched on January 31st 2008 at 20.14 LT from the Andøya Rocket Range in northern Norway (69.31° N, 16.01° E). Measurements in the 75-105 km region of atomic O, negatively-charged dust, positive ions and electrons with a suite of instruments on the payload were complemented by lidar measurements of atomic Na and temperature from the nearby ALOMAR observatory. The payload passed within 2.58 km of the lidar at an altitude of 90 km. A series of coupled models is used to explore the observations, leading to two significant conclusions. First, the atomic Na layer and the vertical profiles of negatively-charged dust (assumed to be meteoric smoke particles), electrons and positive ions, can be modelled using a self-consistent meteoric input flux. Second, electronic structure calculations and Rice-Ramsperger-Kassel-Markus theory are used to show that even small Fe-Mg-silicates are able to attach electrons rapidly and form stable negatively-charged particles, compared with electron attachment to O2 and O3. This explains the substantial electron depletion between 80 and 90 km, where the presence of atomic O at concentrations in excess of 1010 cm-3 prevents the formation of stable negative ions.

  14. Counting the ions surrounding nucleic acids

    PubMed Central

    2017-01-01

    Abstract Nucleic acids are strongly negatively charged, and thus electrostatic interactions—screened by ions in solution—play an important role in governing their ability to fold and participate in biomolecular interactions. The negative charge creates a region, known as the ion atmosphere, in which cation and anion concentrations are perturbed from their bulk values. Ion counting experiments quantify the ion atmosphere by measuring the preferential ion interaction coefficient: the net total number of excess ions above, or below, the number expected due to the bulk concentration. The results of such studies provide important constraints on theories, which typically predict the full three-dimensional distribution of the screening cloud. This article reviews the state of nucleic acid ion counting measurements and critically analyzes their ability to test both analytical and simulation-based models. PMID:28034959

  15. Excess charge driven dissociative hydrogen adsorption on Ti2O4.

    PubMed

    Song, Xiaowei; Fagiani, Matias R; Debnath, Sreekanta; Gao, Min; Maeda, Satoshi; Taketsugu, Tetsuya; Gewinner, Sandy; Schöllkopf, Wieland; Asmis, Knut R; Lyalin, Andrey

    2017-08-30

    The mechanism of dissociative D 2 adsorption on Ti 2 O 4 - , which serves as a model for an oxygen vacancy on a titania surface, is studied using infrared photodissociation spectroscopy in combination with density functional theory calculations and a recently developed single-component artificial force induced reaction method. Ti 2 O 4 - readily reacts with D 2 under multiple collision conditions in a gas-filled ion trap held at 16 K forming a global minimum-energy structure (DO-Ti-(O) 2 -Ti(D)-O) - . The highly exergonic reaction proceeds quasi barrier-free via several intermediate species, involving heterolytic D 2 -bond cleavage followed by D-atom migration. We show that, compared to neutral Ti 2 O 4 , the excess negative charge in Ti 2 O 4 - is responsible for the substantial lowering of the D 2 dissociation barrier, but does not affect the molecular D 2 adsorption energy in the initial physisorption step.

  16. Highly stable CuO incorporated TiO(2) catalyst for photo-catalytic hydrogen production from H(2)O.

    PubMed

    Bandara, J; Udawatta, C P K; Rajapakse, C S K

    2005-11-01

    A CuO incorporated TiO(2) catalyst was found to be an active photo-catalyst for the reduction of H(2)O under sacrificial conditions. The catalytic activity originates from the photogeneration of excited electrons in the conduction bands of both TiO(2) and CuO resulting in a build-up of excess electrons in the conduction band of CuO. Consequently, the accumulation of excess electrons in CuO causes a negative shift in the Fermi level of CuO. The efficient inter-particle charge transfer leads to a higher catalytic activity and the formation of highly reduced states of TiO(2)/CuO, which are stable even under oxygen saturated condition. Negative shift in the Fermi level of CuO of the catalyst TiO(2)/CuO gains the required over-voltage necessary for efficient water reduction reaction. The function of CuO is to help the charge separation and to act as a water reduction site. The amount of CuO and crystalline structure were found to be crucial for the catalytic activity and the optimum CuO loading was ca. approximately 5-10%(w/w).

  17. Surface adsorption of oppositely charged C14TAB-PAMPS mixtures at the air/water interface and the impact on foam film stability.

    PubMed

    Fauser, Heiko; von Klitzing, Regine; Campbell, Richard A

    2015-01-08

    We have studied the oppositely charged polyelectrolyte/surfactant mixture of poly(acrylamidomethylpropanesulfonate) sodium salt (PAMPS) and tetradecyl trimethylammonium bromide (C14TAB) using a combination of neutron reflectivity and ellipsometry measurements. The interfacial composition was determined using three different analysis methods involving the two techniques for the first time. The bulk surfactant concentration was fixed at a modest value while the bulk polyelectrolyte concentration was varied over a wide range. We reveal complex changes in the surface adsorption behavior. Mixtures with low bulk PAMPS concentrations result in the components interacting synergistically in charge neutral layers at the air/water interface. At the bulk composition where PAMPS and C14TAB are mixed in an equimolar charge ratio in the bulk, we observe a dramatic drop in the surfactant surface excess to leave a large excess of polyelectrolyte at the interface, which we infer to have loops in its interfacial structure. Further increase of the bulk PAMPS concentration leads to a more pronounced depletion of material from the surface. Mixtures containing a large excess of PAMPS in the bulk showed enhanced adsorption, which is attributed to the large increase in total ionic strength of the system and screening of the surfactant headgroup charges. The data are compared to our former results on PAMPS/C14TAB mixtures [Kristen et al. J. Phys. Chem. B, 2009, 23, 7986]. A peak in the surface tension is rationalized in terms of the changing surface adsorption and, unlike in more concentrated systems, is unrelated to bulk precipitation. Also, a comparison between the determined interfacial composition with zeta potential and foam film stability data shows that the highest film stability occurs when there is enhanced synergistic adsorption of both components at the interface due to charge screening when the total ionic strength of the system is highest. The additional contribution to the foam stability of the negatively charged polyelectrolyte within the film bulk is also discussed.

  18. Study of space charge layer in silver bromide microcrystals by means of ultraviolet photoelectron spectroscopy

    NASA Astrophysics Data System (ADS)

    Tani, Tadaaki; Inami, Yoshiyasu

    2000-09-01

    Ultraviolet photoelectron spectroscopy has been successfully used to measure the heights of the tops of the valence bands of the surfaces of AgBr layers on Ag substrates for the verification of the space charge layer model. According to this model, the positive space charge layer (composed of negative charges with excess negative kink sites on the surface and corresponding positive charges with interstitial silver ions in the interior) is formed in silver halides, causing the difference in the electronic energy levels between their surface and interior. The depression of the positive space charge layer of AgBr caused by such adsorbates as photographic stabilizers and antifoggants was estimated from the decrease in the ionic conductivity of cubic AgBr microcrystals by the adsorbates. It was confirmed by the decrease in the heights of the tops of the valence bands of the surfaces of AgBr layers caused by the adsorbates in the presence of thin gelatin membranes on their surfaces. This result provided the explanation for the fact that the adsorbates increased the number of the microcrystals which formed latent image centers on the surface and decreased the number of the microcrystals, which formed latent image centers in the interior.

  19. Control of single-electron charging of metallic nanoparticles onto amorphous silicon surface.

    PubMed

    Weis, Martin; Gmucová, Katarína; Nádazdy, Vojtech; Capek, Ignác; Satka, Alexander; Kopáni, Martin; Cirák, Július; Majková, Eva

    2008-11-01

    Sequential single-electron charging of iron oxide nanoparticles encapsulated in oleic acid/oleyl amine envelope and deposited by the Langmuir-Blodgett technique onto Pt electrode covered with undoped hydrogenated amorphous silicon film is reported. Single-electron charging (so-called quantized double-layer charging) of nanoparticles is detected by cyclic voltammetry as current peaks and the charging effect can be switched on/off by the electric field in the surface region induced by the excess of negative/positive charged defect states in the amorphous silicon layer. The particular charge states in amorphous silicon are created by the simultaneous application of a suitable bias voltage and illumination before the measurement. The influence of charged states on the electric field in the surface region is evaluated by the finite element method. The single-electron charging is analyzed by the standard quantized double layer model as well as two weak-link junctions model. Both approaches are in accordance with experiment and confirm single-electron charging by tunnelling process at room temperature. This experiment illustrates the possibility of the creation of a voltage-controlled capacitor for nanotechnology.

  20. Insight into acid-base nucleation experiments by comparison of the chemical composition of positive, negative, and neutral clusters.

    PubMed

    Bianchi, Federico; Praplan, Arnaud P; Sarnela, Nina; Dommen, Josef; Kürten, Andreas; Ortega, Ismael K; Schobesberger, Siegfried; Junninen, Heikki; Simon, Mario; Tröstl, Jasmin; Jokinen, Tuija; Sipilä, Mikko; Adamov, Alexey; Amorim, Antonio; Almeida, Joao; Breitenlechner, Martin; Duplissy, Jonathan; Ehrhart, Sebastian; Flagan, Richard C; Franchin, Alessandro; Hakala, Jani; Hansel, Armin; Heinritzi, Martin; Kangasluoma, Juha; Keskinen, Helmi; Kim, Jaeseok; Kirkby, Jasper; Laaksonen, Ari; Lawler, Michael J; Lehtipalo, Katrianne; Leiminger, Markus; Makhmutov, Vladimir; Mathot, Serge; Onnela, Antti; Petäjä, Tuukka; Riccobono, Francesco; Rissanen, Matti P; Rondo, Linda; Tomé, António; Virtanen, Annele; Viisanen, Yrjö; Williamson, Christina; Wimmer, Daniela; Winkler, Paul M; Ye, Penglin; Curtius, Joachim; Kulmala, Markku; Worsnop, Douglas R; Donahue, Neil M; Baltensperger, Urs

    2014-12-02

    We investigated the nucleation of sulfuric acid together with two bases (ammonia and dimethylamine), at the CLOUD chamber at CERN. The chemical composition of positive, negative, and neutral clusters was studied using three Atmospheric Pressure interface-Time Of Flight (APi-TOF) mass spectrometers: two were operated in positive and negative mode to detect the chamber ions, while the third was equipped with a nitrate ion chemical ionization source allowing detection of neutral clusters. Taking into account the possible fragmentation that can happen during the charging of the ions or within the first stage of the mass spectrometer, the cluster formation proceeded via essentially one-to-one acid-base addition for all of the clusters, independent of the type of the base. For the positive clusters, the charge is carried by one excess protonated base, while for the negative clusters it is carried by a deprotonated acid; the same is true for the neutral clusters after these have been ionized. During the experiments involving sulfuric acid and dimethylamine, it was possible to study the appearance time for all the clusters (positive, negative, and neutral). It appeared that, after the formation of the clusters containing three molecules of sulfuric acid, the clusters grow at a similar speed, independent of their charge. The growth rate is then probably limited by the arrival rate of sulfuric acid or cluster-cluster collision.

  1. Polarization of gold in nanopores leads to ion current rectification

    DOE PAGES

    Yang, Crystal; Hinkle, Preston; Menestrina, Justin; ...

    2016-10-03

    Biomimetic nanopores with rectifying properties are relevant components of ionic switches, ionic circuits, and biological sensors. Rectification indicates that currents for voltages of one polarity are higher than currents for voltages of the opposite polarity. Ion current rectification requires the presence of surface charges on the pore walls, achieved either by the attachment of charged groups or in multielectrode systems by applying voltage to integrated gate electrodes. Here we present a simpler concept for introducing surface charges via polarization of a thin layer of Au present at one entrance of a silicon nitride nanopore. In an electric field applied bymore » two electrodes placed in bulk solution on both sides of the membrane, the Au layer polarizes such that excess positive charge locally concentrates at one end and negative charge concentrates at the other end. Consequently, a junction is formed between zones with enhanced anion and cation concentrations in the solution adjacent to the Au layer. This bipolar double layer together with enhanced cation concentration in a negatively charged silicon nitride nanopore leads to voltage-controlled surface-charge patterns and ion current rectification. The experimental findings are supported by numerical modeling that confirm modulation of ionic concentrations by the Au layer and ion current rectification even in low-aspect ratio nanopores. Lastly, our findings enable a new strategy for creating ionic circuits with diodes and transistors.« less

  2. Corrosion resistant positive electrode for high-temperature, secondary electrochemical cell

    DOEpatents

    Otto, Neil C.; Warner, Barry T.; Smaga, John A.; Battles, James E.

    1983-01-01

    The corrosion rate of low carbon steel within a positive electrode of a high-temperature, secondary electrochemical cell that includes FeS as active material is substantially reduced by incorporating therein finely divided iron powder in stoichiometric excess to the amount required to form FeS in the fully charged electrode. The cell typically includes an alkali metal or alkaline earth metal as negative electrode active material and a molten metal halide salt as electrolyte. The excess iron permits use of inexpensive carbon steel alloys that are substantially free of the costly corrosion resistant elements chromium, nickel and molybdenum while avoiding shorten cell life resulting from high corrosion rates.

  3. Corrosion resistant positive electrode for high-temperature, secondary electrochemical cell

    DOEpatents

    Otto, N.C.; Warner, B.T.; Smaga, J.A.; Battles, J.E.

    1982-07-07

    The corrosion rate of low carbon steel within a positive electrode of a high-temperature, secondary electrochemical cell that includes FeS as active material is substantially reduced by incorporating therein finely divided iron powder in stoichiometric excess to the amount required to form FeS in the fully charged electrode. The cell typically includes an alkali metal or alkaline earth metal as negative electrode active material and a molten metal halide salt as electrolyte. The excess iron permits use of inexpensive carbon steel alloys that are substantially free of the costly corrosion resistant elements chromium, nickel and molybdenum while avoiding shorten cell life resulting from high corrosion rates.

  4. Charge exchange system

    DOEpatents

    Anderson, Oscar A.

    1978-01-01

    An improved charge exchange system for substantially reducing pumping requirements of excess gas in a controlled thermonuclear reactor high energy neutral beam injector. The charge exchange system utilizes a jet-type blanket which acts simultaneously as the charge exchange medium and as a shield for reflecting excess gas.

  5. Dynamic structure mediates halophilic adaptation of a DNA polymerase from the deep-sea brines of the Red Sea.

    PubMed

    Takahashi, Masateru; Takahashi, Etsuko; Joudeh, Luay I; Marini, Monica; Das, Gobind; Elshenawy, Mohamed M; Akal, Anastassja; Sakashita, Kosuke; Alam, Intikhab; Tehseen, Muhammad; Sobhy, Mohamed A; Stingl, Ulrich; Merzaban, Jasmeen S; Di Fabrizio, Enzo; Hamdan, Samir M

    2018-01-24

    The deep-sea brines of the Red Sea are remote and unexplored environments characterized by high temperatures, anoxic water, and elevated concentrations of salt and heavy metals. This environment provides a rare system to study the interplay between halophilic and thermophilic adaptation in biologic macromolecules. The present article reports the first DNA polymerase with halophilic and thermophilic features. Biochemical and structural analysis by Raman and circular dichroism spectroscopy showed that the charge distribution on the protein's surface mediates the structural balance between stability for thermal adaptation and flexibility for counteracting the salt-induced rigid and nonfunctional hydrophobic packing. Salt bridge interactions via increased negative and positive charges contribute to structural stability. Salt tolerance, conversely, is mediated by a dynamic structure that becomes more fixed and functional with increasing salt concentration. We propose that repulsive forces among excess negative charges, in addition to a high percentage of negatively charged random coils, mediate this structural dynamism. This knowledge enabled us to engineer a halophilic version of KOD DNA polymerase.-Takahashi, M., Takahashi, E., Joudeh, L. I., Marini, M., Das, G., Elshenawy, M. M., Akal, A., Sakashita, K., Alam, I., Tehseen, M., Sobhy, M. A., Stingl, U., Merzaban, J. S., Di Fabrizio, E., Hamdan, S. M. Dynamic structure mediates halophilic adaptation of a DNA polymerase from the deep-sea brines of the Red Sea.

  6. Probing the radio emission from air showers with polarization measurements

    NASA Astrophysics Data System (ADS)

    Aab, A.; Abreu, P.; Aglietta, M.; Ahlers, M.; Ahn, E. J.; Albuquerque, I. F. M.; Allekotte, I.; Allen, J.; Allison, P.; Almela, A.; Alvarez Castillo, J.; Alvarez-Muñiz, J.; Alves Batista, R.; Ambrosio, M.; Aminaei, A.; Anchordoqui, L.; Andringa, S.; Antičić, T.; Aramo, C.; Arqueros, F.; Asorey, H.; Assis, P.; Aublin, J.; Ave, M.; Avenier, M.; Avila, G.; Badescu, A. M.; Barber, K. B.; Bardenet, R.; Bäuml, J.; Baus, C.; Beatty, J. J.; Becker, K. H.; Bellido, J. A.; BenZvi, S.; Berat, C.; Bertou, X.; Biermann, P. L.; Billoir, P.; Blanco, F.; Blanco, M.; Bleve, C.; Blümer, H.; Boháčová, M.; Boncioli, D.; Bonifazi, C.; Bonino, R.; Borodai, N.; Brack, J.; Brancus, I.; Brogueira, P.; Brown, W. C.; Buchholz, P.; Bueno, A.; Buscemi, M.; Caballero-Mora, K. S.; Caccianiga, B.; Caccianiga, L.; Candusso, M.; Caramete, L.; Caruso, R.; Castellina, A.; Cataldi, G.; Cazon, L.; Cester, R.; Cheng, S. H.; Chiavassa, A.; Chinellato, J. A.; Chudoba, J.; Cilmo, M.; Clay, R. W.; Cocciolo, G.; Colalillo, R.; Collica, L.; Coluccia, M. R.; Conceição, R.; Contreras, F.; Cooper, M. J.; Coutu, S.; Covault, C. E.; Criss, A.; Cronin, J.; Curutiu, A.; Dallier, R.; Daniel, B.; Dasso, S.; Daumiller, K.; Dawson, B. R.; de Almeida, R. M.; De Domenico, M.; de Jong, S. J.; De La Vega, G.; de Mello Junior, W. J. M.; de Mello Neto, J. R. T.; De Mitri, I.; de Souza, V.; de Vries, K. D.; del Peral, L.; Deligny, O.; Dembinski, H.; Dhital, N.; Di Giulio, C.; Di Matteo, A.; Diaz, J. C.; Díaz Castro, M. L.; Diep, P. N.; Diogo, F.; Dobrigkeit, C.; Docters, W.; D'Olivo, J. C.; Dong, P. N.; Dorofeev, A.; dos Anjos, J. C.; Dova, M. T.; Ebr, J.; Engel, R.; Erdmann, M.; Escobar, C. O.; Espadanal, J.; Etchegoyen, A.; Facal San Luis, P.; Falcke, H.; Fang, K.; Farrar, G.; Fauth, A. C.; Fazzini, N.; Ferguson, A. P.; Fick, B.; Figueira, J. M.; Filevich, A.; Filipčič, A.; Foerster, N.; Fox, B. D.; Fracchiolla, C. E.; Fraenkel, E. D.; Fratu, O.; Fröhlich, U.; Fuchs, B.; Gaior, R.; Gamarra, R. F.; Gambetta, S.; García, B.; Garcia Roca, S. T.; Garcia-Gamez, D.; Garcia-Pinto, D.; Garilli, G.; Gascon Bravo, A.; Gemmeke, H.; Ghia, P. L.; Giammarchi, M.; Giller, M.; Gitto, J.; Glaser, C.; Glass, H.; Gomez Albarracin, F.; Gómez Berisso, M.; Gómez Vitale, P. F.; Gonçalves, P.; Gonzalez, J. G.; Gookin, B.; Gorgi, A.; Gorham, P.; Gouffon, P.; Grebe, S.; Griffith, N.; Grillo, A. F.; Grubb, T. D.; Guardincerri, Y.; Guarino, F.; Guedes, G. P.; Hansen, P.; Harari, D.; Harrison, T. A.; Harton, J. L.; Haungs, A.; Hebbeker, T.; Heck, D.; Herve, A. E.; Hill, G. C.; Hojvat, C.; Hollon, N.; Holt, E.; Homola, P.; Hörandel, J. R.; Horvath, P.; Hrabovský, M.; Huber, D.; Huege, T.; Insolia, A.; Isar, P. G.; Jansen, S.; Jarne, C.; Josebachuili, M.; Kadija, K.; Kambeitz, O.; Kampert, K. H.; Karhan, P.; Kasper, P.; Katkov, I.; Kégl, B.; Keilhauer, B.; Keivani, A.; Kemp, E.; Kieckhafer, R. M.; Klages, H. O.; Kleifges, M.; Kleinfeller, J.; Knapp, J.; Krause, R.; Krohm, N.; Krömer, O.; Kruppke-Hansen, D.; Kuempel, D.; Kunka, N.; La Rosa, G.; LaHurd, D.; Latronico, L.; Lauer, R.; Lauscher, M.; Lautridou, P.; Le Coz, S.; Leão, M. S. A. B.; Lebrun, D.; Lebrun, P.; Leigui de Oliveira, M. A.; Letessier-Selvon, A.; Lhenry-Yvon, I.; Link, K.; López, R.; Lopez Agüera, A.; Louedec, K.; Lozano Bahilo, J.; Lu, L.; Lucero, A.; Ludwig, M.; Lyberis, H.; Maccarone, M. C.; Malacari, M.; Maldera, S.; Maller, J.; Mandat, D.; Mantsch, P.; Mariazzi, A. G.; Marin, V.; Mariş, I. C.; Marquez Falcon, H. R.; Marsella, G.; Martello, D.; Martin, L.; Martinez, H.; Martínez Bravo, O.; Martraire, D.; Masías Meza, J. J.; Mathes, H. J.; Matthews, J.; Matthews, J. A. J.; Matthiae, G.; Maurel, D.; Maurizio, D.; Mayotte, E.; Mazur, P. O.; Medina, C.; Medina-Tanco, G.; Melissas, M.; Melo, D.; Menichetti, E.; Menshikov, A.; Messina, S.; Meyhandan, R.; Mićanović, S.; Micheletti, M. I.; Middendorf, L.; Minaya, I. A.; Miramonti, L.; Mitrica, B.; Molina-Bueno, L.; Mollerach, S.; Monasor, M.; Monnier Ragaigne, D.; Montanet, F.; Morales, B.; Morello, C.; Moreno, J. C.; Mostafá, M.; Moura, C. A.; Muller, M. A.; Müller, G.; Münchmeyer, M.; Mussa, R.; Navarra, G.; Navarro, J. L.; Navas, S.; Necesal, P.; Nellen, L.; Nelles, A.; Neuser, J.; Nhung, P. T.; Niechciol, M.; Niemietz, L.; Niggemann, T.; Nitz, D.; Nosek, D.; Nožka, L.; Oehlschläger, J.; Olinto, A.; Oliveira, M.; Ortiz, M.; Pacheco, N.; Pakk Selmi-Dei, D.; Palatka, M.; Pallotta, J.; Palmieri, N.; Parente, G.; Parra, A.; Pastor, S.; Paul, T.; Pech, M.; PeÂķala, J.; Pelayo, R.; Pepe, I. M.; Perrone, L.; Pesce, R.; Petermann, E.; Petrera, S.; Petrolini, A.; Petrov, Y.; Piegaia, R.; Pierog, T.; Pieroni, P.; Pimenta, M.; Pirronello, V.; Platino, M.; Plum, M.; Pontz, M.; Porcelli, A.; Preda, T.; Privitera, P.; Prouza, M.; Quel, E. J.; Querchfeld, S.; Quinn, S.; Rautenberg, J.; Ravel, O.; Ravignani, D.; Revenu, B.; Ridky, J.; Riggi, S.; Risse, M.; Ristori, P.; Rivera, H.; Rizi, V.; Roberts, J.; Rodrigues de Carvalho, W.; Rodriguez Cabo, I.; Rodriguez Fernandez, G.; Rodriguez Martino, J.; Rodriguez Rojo, J.; Rodríguez-Frías, M. D.; Ros, G.; Rosado, J.; Rossler, T.; Roth, M.; Rouillé-d'Orfeuil, B.; Roulet, E.; Rovero, A. C.; Rühle, C.; Saffi, S. J.; Saftoiu, A.; Salamida, F.; Salazar, H.; Salesa Greus, F.; Salina, G.; Sánchez, F.; Sanchez-Lucas, P.; Santo, C. E.; Santos, E.; Santos, E. M.; Sarazin, F.; Sarkar, B.; Sarmento, R.; Sato, R.; Scharf, N.; Scherini, V.; Schieler, H.; Schiffer, P.; Schmidt, A.; Scholten, O.; Schoorlemmer, H.; Schovánek, P.; Schröder, F. G.; Schulz, A.; Schulz, J.; Sciutto, S. J.; Scuderi, M.; Segreto, A.; Settimo, M.; Shadkam, A.; Shellard, R. C.; Sidelnik, I.; Sigl, G.; Sima, O.; Śmiałkowski, A.; Šmída, R.; Snow, G. R.; Sommers, P.; Sorokin, J.; Spinka, H.; Squartini, R.; Srivastava, Y. N.; Stanič, S.; Stapleton, J.; Stasielak, J.; Stephan, M.; Straub, M.; Stutz, A.; Suarez, F.; Suomijärvi, T.; Supanitsky, A. D.; Šuša, T.; Sutherland, M. S.; Swain, J.; Szadkowski, Z.; Szuba, M.; Tapia, A.; Tartare, M.; Taşcǎu, O.; Thao, N. T.; Tiffenberg, J.; Timmermans, C.; Tkaczyk, W.; Todero Peixoto, C. J.; Toma, G.; Tomankova, L.; Tomé, B.; Tonachini, A.; Torralba Elipe, G.; Torres Machado, D.; Travnicek, P.; Tridapalli, D. B.; Trovato, E.; Tueros, M.; Ulrich, R.; Unger, M.; Valdés Galicia, J. F.; Valiño, I.; Valore, L.; van Aar, G.; van den Berg, A. M.; van Velzen, S.; van Vliet, A.; Varela, E.; Vargas Cárdenas, B.; Varner, G.; Vázquez, J. R.; Vázquez, R. A.; Veberič, D.; Verzi, V.; Vicha, J.; Videla, M.; Villaseñor, L.; Wahlberg, H.; Wahrlich, P.; Wainberg, O.; Walz, D.; Watson, A. A.; Weber, M.; Weidenhaupt, K.; Weindl, A.; Werner, F.; Westerhoff, S.; Whelan, B. J.; Widom, A.; Wieczorek, G.; Wiencke, L.; Wilczyńska, B.; Wilczyński, H.; Will, M.; Williams, C.; Winchen, T.; Wundheiler, B.; Wykes, S.; Yamamoto, T.; Yapici, T.; Younk, P.; Yuan, G.; Yushkov, A.; Zamorano, B.; Zas, E.; Zavrtanik, D.; Zavrtanik, M.; Zaw, I.; Zepeda, A.; Zhou, J.; Zhu, Y.; Zimbres Silva, M.; Ziolkowski, M.; Pierre Auger Collaboration

    2014-03-01

    The emission of radio waves from air showers has been attributed to the so-called geomagnetic emission process. At frequencies around 50 MHz this process leads to coherent radiation which can be observed with rather simple setups. The direction of the electric field induced by this emission process depends only on the local magnetic field vector and on the incoming direction of the air shower. We report on measurements of the electric field vector where, in addition to this geomagnetic component, another component has been observed that cannot be described by the geomagnetic emission process. The data provide strong evidence that the other electric field component is polarized radially with respect to the shower axis, in agreement with predictions made by Askaryan who described radio emission from particle showers due to a negative charge excess in the front of the shower. Our results are compared to calculations which include the radiation mechanism induced by this charge-excess process.

  7. Simple Pencil-and-Paper Notation for Representing Electrical Charge States

    NASA Astrophysics Data System (ADS)

    Morse, Robert A.

    2017-11-01

    In Benjamin Franklin's one fluid theory of electrification, ordinary unelectrified matter consisted of a matrix of matter suffused with a certain amount of "electrical fluid." Electrical effects were due to an excess or deficit of electrical fluid, hence the terms positive and negative. Before the development of a modern view of the atom, diagrams showing charged objects would simply have "+" or "-" signs to indicate the charged state. As physicists we know how to interpret these diagrams and understand what they are telling us about the underlying atomic model of charging. However, novice students may not readily make the connection between the atomic model, in which a charged solid object either gains or loses electrons but does not gain or lose positive charges. Furthermore, when isolated objects become charged, the total number of electrons must be accounted for as charge is a conserved quantity. To really understand the changes that occur in charging by contact, conduction, or induction, it is useful for students to visually represent the processes in a way that emphasizes the atomicity of the processes, including the induced polarization of objects, and the requirement that charge be conserved.

  8. Silver-silver sulfate reference electrodes for use in lead-acid batteries

    NASA Astrophysics Data System (ADS)

    Ruetschi, Paul

    Electrochemical properties of silver-silver sulfate reference electrodes for lead-acid batteries are described, and the following possible applications discussed: Determination of individual capacities of positive and negative plates. Monitoring individual electrode behavior during deep discharge and cell reversal. Optimization charge or discharge parameters, by controlling the current such that pre-determined limits of positive or negative half-cell potential are respected. Observation of acid concentration differences, for example due to acid stratification, by measuring diffusion potentials (concentration-cell voltages). Detection of defective cells, and defective plate sets, in a string of cells, at the end of their service life. Silver-silver sulfate reference electrodes, permanently installed in lead-acid cells, may be a means to improve battery management, and therewith to improve reliability and service life. In vented batteries, reference electrodes may be used to limit positive plate polarization during charge, or float-charge. Limiting the positive half-cell potential to an upper, pre-set value would permit to keep anodic corrosion as low as possible. During cycling, discharge could be terminated when the half-cell potential of the positive electrode has dropped to a pre-set limit. This would prevent excessive discharge of the positive electrodes, which could result in an improvement of cycle life. In valve-regulated batteries, reference electrodes may be used to adjust float-charge conditions such as to assure sufficient cathodic polarization of the negative electrodes, in order to avoid sulfation. The use of such reference electrodes could be beneficial particularly in multi-cell batteries, with overall voltages above 12 V, operated in a partial-state-of-charge.

  9. A physically-based analytical model to describe effective excess charge for streaming potential generation in saturated porous media

    NASA Astrophysics Data System (ADS)

    Jougnot, D.; Guarracino, L.

    2016-12-01

    The self-potential (SP) method is considered by most researchers the only geophysical method that is directly sensitive to groundwater flow. One source of SP signals, the so-called streaming potential, results from the presence of an electrical double layer at the mineral-pore water interface. When water flows through the pore space, it gives rise to a streaming current and a resulting measurable electrical voltage. Different approaches have been proposed to predict streaming potentials in porous media. One approach is based on the excess charge which is effectively dragged in the medium by the water flow. Following a recent theoretical framework, we developed a physically-based analytical model to predict the effective excess charge in saturated porous media. In this study, the porous media is described by a bundle of capillary tubes with a fractal pore-size distribution. First, an analytical relationship is derived to determine the effective excess charge for a single capillary tube as a function of the pore water salinity. Then, this relationship is used to obtain both exact and approximated expressions for the effective excess charge at the Representative Elementary Volume (REV) scale. The resulting analytical relationship allows the determination of the effective excess charge as a function of pore water salinity, fractal dimension and hydraulic parameters like porosity and permeability, which are also obtained at the REV scale. This new model has been successfully tested against data from the literature of different sources. One of the main finding of this study is that it provides a mechanistic explanation to the empirical dependence between the effective excess charge and the permeability that has been found by various researchers. The proposed petrophysical relationship also contributes to understand the role of porosity and water salinity on effective excess charge and will help to push further the use of streaming potential to monitor groundwater flow.

  10. Intermolecular Interaction between Phosphatidylcholine and Sulfobetaine Lipid: A Combination of Lipids with Antiparallel Arranged Headgroup Charge.

    PubMed

    Aikawa, Tatsuo; Yokota, Keisuke; Kondo, Takeshi; Yuasa, Makoto

    2016-10-05

    Intermolecular interactions between lipid molecules are important when designing lipid bilayer interfaces, which have many biomedical applications such as in drug delivery vehicles and biosensors. Phosphatidylcholine, a naturally occurring lipid, is the most common lipid found in organisms. Its chemical structure has a negatively charged phosphate linkage, adjacent to an ester linkage in a glycerol moiety, and a positively charged choline group, placed at the terminus of the molecule. Recently, several types of synthetic lipids that have headgroups with the opposite charge to that of phosphatidylcholine have emerged; that is, a positively charged ammonium group is present adjacent to the ester linkage in their glycerol moiety and a negatively charged group is placed at their terminus. These types of lipids constitute a new class of soft material. The aim of this study was to determine how such lipids, with antiparallel arranged headgroup charge, interact with naturally occurring phosphatidylcholines. We synthesized 1,2-dipalmitoyl-sn-glycero-3-sulfobetaine (DPSB) to represent a reversed-head lipid; 1,2-dipalmitoyl-sn-glycero-3-phosphatidylcholine (DPPC) was used to represent a naturally occurring phospholipid. The intermolecular interaction between these lipids was investigated using surface pressure-area (π-A) isotherms of the lipid monolayer at the air/water interface. We found that the extrapolated area and excess free energy of the mixed monolayer deviated negatively when compared with the ideal values from additivity. Moreover, differential scanning calorimetry of the lipid mixture in aqueous dispersion showed that the gel-to-liquid crystal transition temperature increased compared with that of each pure lipid composition. These results clearly indicate that DPSB preferably interacts with DPPC in the mixture. We believe that the attraction between the oppositely charged headgroups of these lipids reinforces the intermolecular interaction. Our results provide insight into the intermolecular interaction between phospholipids and reversed-head lipids, which may prove useful for the design of lipid-based materials in the future.

  11. SEMICONDUCTOR TECHNOLOGY: Influence of nitrogen dose on the charge density of nitrogen-implanted buried oxide in SOI wafers

    NASA Astrophysics Data System (ADS)

    Zhongshan, Zheng; Zhongli, Liu; Ning, Li; Guohua, Li; Enxia, Zhang

    2010-02-01

    To harden silicon-on-insulator (SOI) wafers fabricated using separation by implanted oxygen (SIMOX) to total-dose irradiation, the technique of nitrogen implantation into the buried oxide (BOX) layer of SIMOX wafers can be used. However, in this work, it has been found that all the nitrogen-implanted BOX layers reveal greater initial positive charge densities, which increased with increasing nitrogen implantation dose. Also, the results indicate that excessively large nitrogen implantation dose reduced the radiation tolerance of BOX for its high initial positive charge density. The bigger initial positive charge densities can be ascribed to the accumulation of implanted nitrogen near the Si-BOX interface after annealing. On the other hand, in our work, it has also been observed that, unlike nitrogen-implanted BOX, all the fluorine-implanted BOX layers show a negative charge density. To obtain the initial charge densities of the BOX layers, the tested samples were fabricated with a metal-BOX-silicon (MBS) structure based on SIMOX wafers for high-frequency capacitance-voltage (C-V) analysis.

  12. Complexation between sodium dodecyl sulfate and amphoteric polyurethane nanoparticles.

    PubMed

    Qiao, Yong; Zhang, Shifeng; Lin, Ouya; Deng, Liandong; Dong, Anjie

    2007-09-27

    The complexation between negatively charged sodium dodecyl sulfate (SDS) and positively charged amphoteric polyurethane (APU) self-assembled nanoparticles (NPs) containing nonionic hydrophobic segments is studied by dynamic light scattering, pyrene fluorescent probing, zeta-potential, and transmission electron microscopy (TEM) in the present paper. With increasing the mol ratio of SDS to the positive charges on the surface of APU NPs, the aqueous solution of APU NPs presents precipitation at pH 2, around stoichiometric SDS concentration, and then the precipitate dissociates with excess SDS to form more stable nanoparticles of ionomer complexes. Three stages of the complexation process are clearly shown by the pyrene I1/I3 variation of the complex systems, which only depends on the ratio of SDS/APU, and demonstrate that the process is dominated by electrostatic attraction and hydrophobic aggregation.

  13. Characterization and charge distribution of the asparagine-linked oligosaccharides on secreted mouse thyrotropin and free alpha-subunits

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Gesundheit, N.; Gyves, P.W.; DeCherney, G.S.

    1989-06-01

    Mouse hemipituitaries in vitro secrete TSH, composed of an alpha-beta heterodimer, as well as excess (free) alpha-subunits. By dual metabolic labeling with (35S)sulfate and (3H)mannose, we have characterized oligosaccharides from secreted TSH alpha, TSH beta, and free alpha-subunits released from the apoprotein by enzymatic deglycosylation. Oligosaccharides from each subunit displayed a distinct anion exchange HPLC profile due to a specific pattern of sialylation and sulfation. Six species were obtained from TSH alpha (with two glycosylation sites), including neutral oligosaccharides as well as those with one or two negative charges. For TSH beta (with one glycosylation site) at least eight oligosaccharidemore » species were noted, representing nearly every permutation of sialylation and sulfation; approximately 30% contained three or more negative charges. Analysis of (3H)mannose-labeled oligosaccharides on Concanavalin-A-agarose showed 85% binding for those from TSH alpha, 70% for free alpha, and 50% for those from TSH beta. These data demonstrate that oligosaccharides from secreted TSH beta were more sialylated and sulfated, consistent with a more complex branching pattern, than those from TSH alpha. Oligosaccharides from free alpha-subunit were more sialylated than those from TSH alpha, and the net negative charge was intermediate between those of TSH alpha and TSH beta. Although great microheterogeneity is present even at the single glycosylation site on the beta-subunit of secreted TSH, a pattern of sialylation and sulfation could be discerned.« less

  14. Effect of electric charge on the adhesion of human blood platelets.

    PubMed

    Lowkis, B; Szymonowicz, M

    1993-01-01

    The paper presents the results of research into the effect of the size and depth of the implanted electric charge on the adhesion of human blood platelets. The experiments were carried out on polyethylene terephthalate PET foil of 36 microns thickness. The electret formation process was carried out in an electron-beam device. The electrization conditions were such that electrets with the excess electric charge accumulated at various depths were obtained. The selection of conditions was verified by investigating the space charge distribution with the use of the virtual electrode method. The microscopic observation of non-electrified foils and electrets as well as the quantitative examination of the adhesion of human blood platelets has explicitly confirmed the positive influence of the electret effect on the thrombogenesis of PET foil. This made it possible to define the optimum electrization conditions. The research has additionally indicated that the relationship between the amount of adherent blood platelets and the size of the electric charge is not a simple relation of the kind: the larger negative charge, the more thrombogenic material. The decisive and positive effect of the space charge has been confirmed by analysing the effectiveness of the surface and space charge.

  15. Computer Modeling of Electrostatic Aggregation of Granular Materials in Planetary and Astrophysical Settings

    NASA Technical Reports Server (NTRS)

    Marshall, J.; Sauke, T.

    1999-01-01

    Electrostatic forces strongly influence the behavior of granular materials in both dispersed (cloud) systems and semi-packed systems. These forces can cause aggregation or dispersion of particles and are important in a variety of astrophysical and planetary settings. There are also many industrial and commercial settings where granular matter and electrostatics become partners for both good and bad. This partnership is important for human exploration on Mars where dust adheres to suits, machines, and habitats. Long-range Coulombic (electrostatic) forces, as opposed to contact-induced dipoles and van der Waals attractions, are generally regarded as resulting from net charge. We have proposed that in addition to net charge interactions, randomly distributed charge carriers on grains will result in a dipole moment regardless of any net charge. If grains are unconfined, or fluidized, they will rotate so that the dipole always induces attraction between grains. Aggregates are readily formed, and Coulombic polarity resulting from the dipole produces end-to-end stacking of grains to form filamentary aggregates. This has been demonstrated in USML experiments on Space Shuttle where microgravity facilitated the unmasking of static forces. It has also been demonstrated in a computer model using grains with charge carriers of both sign. Model results very closely resembled micro-g results with actual sand grains. Further computer modeling of the aggregation process has been conducted to improve our understanding of the aggregation process, and to provide a predictive tool for microgravity experiments slated for Space Station. These experiments will attempt to prove the dipole concept as outlined above. We have considerably enhanced the original computer model: refinements to the algorithm have improved the fidelity of grain behavior during grain contact, special attention has been paid to simulation time steps to enable establishment of a meaningful, quantitative time axis, and calibration of rounding accuracies have been conducted to test cumulative numerical influences in the model. The model has been run for larger grain populations, variable initial cloud densities, and we have introduced random net charging to individual grains, as well as a net charge to the cloud as a whole. The model uses 3 positive and 3 negative charges randomly distributed on each grain, with up to 160 grains contained within various size "boxes" that define the initial number densities in the clouds. Each charge represents localized charged region on a grain, but does not necessarily imply single quantized charge carriers. The Coulomb equations are then allowed to interact for each monopole: dipoles and any higher order charge coupling is a natural product of these "free" interactions over which the modeler exerts no influence. The charges are placed on surfaces of grains at random locations. A series of runs was conducted for neutral grains that had a perfect balance of negative and positive char carriers. Runs were also conducted with grains having additional fractional charges ranging between 0 and 1. By adding fractional charges of one sign, the model created grain populations in which all grains had excess charges the same sign, giving the cloud an overall net charge. This simulates clouds subjected to ionizing radiation (e. protoplanetary debris disk around a protosun), or any other process of charge biasing in a grain population (e.g., volcanic plumes). In another run series, random fractional charges of either sign were added to the grains so th some grains had a slight net positive charge while others had a slight net negative charge. This simulates triboelectrically-charged grain populations in which acquisition of an electron by one surface is at the expense creating a hole elsewhere. This dual sign charging was applied in two ways: in one case the cloud remained neutral by ensuring that all grain excess charges added to zero; in the other case, the cloud was permitted slight net char by not imposing a charge-balance condition. Additional information is contained in the original.

  16. A Physically Based Analytical Model to Describe Effective Excess Charge for Streaming Potential Generation in Water Saturated Porous Media

    NASA Astrophysics Data System (ADS)

    Guarracino, L.; Jougnot, D.

    2018-01-01

    Among the different contributions generating self-potential, the streaming potential is of particular interest in hydrogeology for its sensitivity to water flow. Estimating water flux in porous media using streaming potential data relies on our capacity to understand, model, and upscale the electrokinetic coupling at the mineral-solution interface. Different approaches have been proposed to predict streaming potential generation in porous media. One of these approaches is the flux averaging which is based on determining the excess charge which is effectively dragged in the medium by water flow. In this study, we develop a physically based analytical model to predict the effective excess charge in saturated porous media using a flux-averaging approach in a bundle of capillary tubes with a fractal pore size distribution. The proposed model allows the determination of the effective excess charge as a function of pore water ionic concentration and hydrogeological parameters like porosity, permeability, and tortuosity. The new model has been successfully tested against different set of experimental data from the literature. One of the main findings of this study is the mechanistic explanation to the empirical dependence between the effective excess charge and the permeability that has been found by several researchers. The proposed model also highlights the link to other lithological properties, and it is able to reproduce the evolution of effective excess charge with electrolyte concentrations.

  17. The role of interfacial water layer in atmospherically relevant charge separation

    NASA Astrophysics Data System (ADS)

    Bhattacharyya, Indrani

    Charge separation at interfaces is important in various atmospheric processes, such as thunderstorms, lightning, and sand storms. It also plays a key role in several industrial processes, including ink-jet printing and electrostatic separation. Surprisingly, little is known about the underlying physics of these charging phenomena. Since thin films of water are ubiquitous, they may play a role in these charge separation processes. This talk will focus on the experimental investigation of the role of a water adlayer in interfacial charging, with relevance to meteorologically important phenomena, such as atmospheric charging due to wave actions on oceans and sand storms. An ocean wave generates thousands of bubbles, which upon bursting produce numerous large jet droplets and small film droplets that are charged. In the 1960s, Blanchard showed that the jet droplets are positively charged. However, the charge on the film droplets was not known. We designed an experiment to exclusively measure the charge on film droplets generated by bubble bursting on pure water and aqueous salt solution surfaces. We measured their charge to be negative and proposed a model where a slight excess of hydroxide ions in the interfacial water layer is responsible for generating these negatively charged droplets. The findings from this research led to a better understanding of the ionic disposition at the air-water interface. Sand particles in a wind-blown sand layer, or 'saltation' layer, become charged due to collisions, so much so, that it can cause lightning. Silica, being hydrophilic, is coated with a water layer even under low-humidity conditions. To investigate the importance of this water adlayer in charging the silica surfaces, we performed experiments to measure the charge on silica surfaces due to contact and collision processes. In case of contact charging, the maximum charge separation occurred at an optimum relative humidity. On the contrary, in collisional charging process, no humidity effect was observed. We proposed an ion transfer mechanism in case of contact charging. However, an electron transfer mechanism explained the collisional charging process. The effects of temperature, surface roughness, and chemical nature of surface were also studied for both contact and collisional charging processes.

  18. A general theory for ball lightning structure and light output

    NASA Astrophysics Data System (ADS)

    Morrow, R.

    2018-03-01

    A general theory for free-floating ball lightning is presented which unifies the phantom plasma ball theory involving the production of very little light, with theories for ball lightning involving light output produced by burning particles from the soil. The mechanism for the formation of plasma balls is shown to be quite general, producing very similar plasma balls independent of initial ion densities over four orders of magnitude. All that is required is an excess of positive ions in the initial ball of ions. The central plasma density after 1 s is shown to be the reciprocal of the ion neutralization coefficient for all cases, both analytically and computationally. Further, the plasma region has zero electric field in all cases. Surrounding the plasma ball is a sphere of positive ions moving away from the centre via their own space-charge field; this space-charge field, which is the same in all cases near the plasma ball, drives negative ions and negative particles towards the plasma centre. The connection with burning particle theories is the proposition that the burning particles are highly-charged which is very likely after a lightning strike. Burning negatively charged particles would be driven into the plasma ball region and trapped while any positively charged particles would be driven away. The plasma ball structure is shown to last more than 10 s and the ‘burnout time’ for a typical coal particle (as an example) has been measured at 5-10 s this is comparable with the lifetimes observed for ball lightning. The light output from a few hundred particles is estimated to be ~1 W, a typical output for ball lightning. Finally, suggestions are made for the generation of ball lightning in the laboratory.

  19. Sulfobetaine as a zwitterionic mediator for 3D hydroxyapatite mineralization

    PubMed Central

    Liu, Pingsheng; Song, Jie

    2013-01-01

    Both positively and negatively charged residues play pivotal roles in recruiting precursor ions or ion clusters, and lowering interfacial energy in natural biomineralization process. Synergistic utilization of opposite charges, however, has rarely been implemented in the design of cytocompatible synthetic scaffolds promoting hydroxyapatite (HA)-mineralization and osteointegration. We report the use of cytocompatible zwitterionic sulfobetaine ligands to enable 3-dimensional in vitro mineralization of HA across covalently crosslinked hydrogels. The overall charge-neutral zwitterionic hydrogel effectively recruited oppositely charged precursor ions while overcame excessive swelling exhibited by anionic and cationic hydrogels under physiological conditions, resulting in denser and structurally well-integrated mineralized composites. Further controls over the size, content, and spatial distribution of the mineral domains within the zwitterionic hydrogel are accomplished by facile adjustments of hydrogel crosslinking densities and the supersaturation rate governing heterogeneous mineral nucleation and growth. These findings should inspire many creative uses of zwitterionic polymers and polymer coatings for skeletal tissue repair and regeneration. PMID:23332320

  20. Sulfobetaine as a zwitterionic mediator for 3D hydroxyapatite mineralization.

    PubMed

    Liu, Pingsheng; Song, Jie

    2013-03-01

    Both positively and negatively charged residues play pivotal roles in recruiting precursor ions or ion clusters, and lowering interfacial energy in natural biomineralization process. Synergistic utilization of opposite charges, however, has rarely been implemented in the design of cytocompatible synthetic scaffolds promoting hydroxyapatite (HA)-mineralization and osteointegration. We report the use of cytocompatible zwitterionic sulfobetaine ligands to enable 3-dimensional in vitro mineralization of HA across covalently crosslinked hydrogels. The overall charge-neutral zwitterionic hydrogel effectively recruited oppositely charged precursor ions while overcame excessive swelling exhibited by anionic and cationic hydrogels under physiological conditions, resulting in denser and structurally well-integrated mineralized composites. Further controls over the size, content, and spatial distribution of the mineral domains within the zwitterionic hydrogel are accomplished by facile adjustments of hydrogel crosslinking densities and the supersaturation rate governing heterogeneous mineral nucleation and growth. These findings should inspire many creative uses of zwitterionic polymers and polymer coatings for skeletal tissue repair and regeneration. Copyright © 2012 Elsevier Ltd. All rights reserved.

  1. Comparison of Three Model Concepts for Streaming Potential in Unsaturated Porous Media

    NASA Astrophysics Data System (ADS)

    Huisman, J. A.; Satenahalli, P.; Zimmermann, E.; Vereecken, H.

    2017-12-01

    Streaming potential is the electric potential generated by fluid flow in a charged porous medium. Although streaming potential in saturated conditions is well understood, there still is considerable debate about the adequate modelling of streaming potential signals in unsaturated soil because different concepts are available to estimate the effective excess charge in unsaturated conditions. In particular, some studies have relied on the volumetric excess charge, whereas others proposed to use the flux-averaged excess charge derived from the water retention or relative permeability function. The aim of this study is to compare measured and modelled streaming potential signals for two different flow experiments with sand. The first experiment is a primary gravity drainage of a long column equipped with non-polarizing electrodes and tensiometers, as presented in several previous studies. Expected differences between the three concepts for the effective excess charge are only moderate for this set-up. The second experiment is a primary drainage of a short soil column equipped with non-polarizing electrodes and tensiometers using applied pressure, where differences between the three concepts are expected to be larger. A comparison of the experimental results with a coupled model of streaming potential for 1D flow problems will provide insights in the ability of the three model concepts for effective excess charge to describe observed streaming potentials.

  2. Fabrication and testing of negative limited sealed nickel-cadmium cells

    NASA Technical Reports Server (NTRS)

    Gordy, D. J.

    1975-01-01

    A number of 20 Ah and 3 Ah negative limited nickel-cadmium cells were fabricated and assembled in hermetically sealed stainless steel containers. The cells exhibit a large voltage rise signal, in excess of 250 mA, at the end of each charge period. They also exhibit lower self discharge rates than conventional sealed nickel-cadmium cells and do not require overcharge. The cells are capable of operating at charge and discharge rates up to 5C and can deliver at least 1000 cycles on a 30 minute regime at 25% DOD. A small amount of gassing occurs, but is not deemed critical or detrimental in view of the facts that, (1) operating pressures are in the range of 7 to 20 psig and (2) the cells are operated in the flooded condition so therefore contain little internal void volume. The cells were found to exhibit somewhat higher capacity loss rates during cycling than conventional sealed nickel-cadmium batteries.

  3. Uncharged positive electrode composition

    DOEpatents

    Kaun, Thomas D.; Vissers, Donald R.; Shimotake, Hiroshi

    1977-03-08

    An uncharged positive-electrode composition contains particulate lithium sulfide, another alkali metal or alkaline earth metal compound other than sulfide, e.g., lithium carbide, and a transition metal powder. The composition along with a binder, such as electrolytic salt or a thermosetting resin is applied onto an electrically conductive substrate to form a plaque. The plaque is assembled as a positive electrode within an electrochemical cell opposite to a negative electrode containing a material such as aluminum or silicon for alloying with lithium. During charging, lithium alloy is formed within the negative electrode and transition metal sulfide such as iron sulfide is produced within the positive electrode. Excess negative electrode capacity over that from the transition metal sulfide is provided due to the electrochemical reaction of the other than sulfide alkali metal or alkaline earth metal compound.

  4. Modelling CEC variations versus structural iron reduction levels in dioctahedral smectites. Existing approaches, new data and model refinements.

    PubMed

    Hadi, Jebril; Tournassat, Christophe; Ignatiadis, Ioannis; Greneche, Jean Marc; Charlet, Laurent

    2013-10-01

    A model was developed to describe how the 2:1 layer excess negative charge induced by the reduction of Fe(III) to Fe(II) by sodium dithionite buffered with citrate-bicarbonate is balanced and applied to nontronites. This model is based on new experimental data and extends structural interpretation introduced by a former model [36-38]. The 2:1 layer negative charge increase due to Fe(III) to Fe(II) reduction is balanced by an excess adsorption of cations in the clay interlayers and a specific sorption of H(+) from solution. Prevalence of one compensating mechanism over the other is related to the growing lattice distortion induced by structural Fe(III) reduction. At low reduction levels, cation adsorption dominates and some of the incorporated protons react with structural OH groups, leading to a dehydroxylation of the structure. Starting from a moderate reduction level, other structural changes occur, leading to a reorganisation of the octahedral and tetrahedral lattice: migration or release of cations, intense dehydroxylation and bonding of protons to undersaturated oxygen atoms. Experimental data highlight some particular properties of ferruginous smectites regarding chemical reduction. Contrary to previous assumptions, the negative layer charge of nontronites does not only increase towards a plateau value upon reduction. A peak is observed in the reduction domain. After this peak, the negative layer charge decreases upon extended reduction (>30%). The decrease is so dramatic that the layer charge of highly reduced nontronites can fall below that of its fully oxidised counterpart. Furthermore, the presence of a large amount of tetrahedral Fe seems to promote intense clay structural changes and Fe reducibility. Our newly acquired data clearly show that models currently available in the literature cannot be applied to the whole reduction range of clay structural Fe. Moreover, changes in the model normalising procedure clearly demonstrate that the investigated low tetrahedral bearing nontronites (SWa-1, GAN and NAu-1) all exhibit the same behaviour at low reduction levels. Consequently, we restricted our model to the case of moderate reduction (<30%) in low tetrahedral Fe-bearing nontronites. Our adapted model provides the relative amounts of Na(+) (p) and H(+) (ni) cations incorporated in the structure as a function of the amount of Fe reduction. Two equations enable the investigated systems to be described: p=m/(1+Kr·ω·mrel) and ni=Kr·ω·m·mrel/(1+Kr·ω·mrel); where m is the Fe(II) content, mrel, the reduction level (m/mtot), ω, the cation exchange capacity (CEC, and Kr, an empirical constant specific to the system. Copyright © 2013 Elsevier Inc. All rights reserved.

  5. Halophiles and their enzymes: negativity put to good use.

    PubMed

    DasSarma, Shiladitya; DasSarma, Priya

    2015-06-01

    Halophilic microorganisms possess stable enzymes that function in very high salinity, an extreme condition that leads to denaturation, aggregation, and precipitation of most other proteins. Genomic and structural analyses have established that the enzymes of halophilic Archaea and many halophilic Bacteria are negatively charged due to an excess of acidic over basic residues, and altered hydrophobicity, which enhance solubility and promote function in low water activity conditions. Here, we provide an update on recent bioinformatic analysis of predicted halophilic proteomes as well as experimental molecular studies on individual halophilic enzymes. Recent efforts on discovery and utilization of halophiles and their enzymes for biotechnology, including biofuel applications are also considered. Copyright © 2015 Elsevier Ltd. All rights reserved.

  6. Halophiles and their enzymes: Negativity put to good use

    PubMed Central

    DasSarma, Shiladitya; DasSarma, Priya

    2015-01-01

    Halophilic microorganisms possess stable enzymes that function in very high salinity, an extreme condition that leads to denaturation, aggregation, and precipitation of most other proteins. Genomic and structural analyses have established that the enzymes of halophilic Archaea and many halophilic Bacteria are negatively charged due to an excess of acidic over basic residues, and altered hydrophobicity, which enhance solubility and promote function in low water activity conditions. Here, we provide an update on recent bioinformatic analysis of predicted halophilic proteomes as well as experimental molecular studies on individual halophilic enzymes. On-going efforts on discovery and utilization of halophiles and their enzymes for biotechnology, including biofuel applications are also considered. PMID:26066288

  7. Understanding Function and Performance of Carbon Additives in Lead-Acid Batteries

    DOE PAGES

    Enos, D. G.; Ferreira, S. R.; Barkholtz, H. M.; ...

    2017-10-31

    While the low cost and strong safety record of lead-acid batteries make them an appealing option compared to lithium-ion technologies for stationary storage, they can be rapidly degraded by the extended periods of high rate, partial state-of-charge operation required in such applications. Degradation occurs primarily through a process called hard sulfation, where large PbSO 4 crystals are formed on the negative battery plates, hindering charge acceptance and reducing battery capacity. Various researchers have found that the addition of some forms of excess carbon to the negative active mass in lead-acid batteries can mitigate hard sulfation, but the mechanism through whichmore » this is accomplished is unclear. In this work, the effect of carbon composition and morphology was explored by characterizing four discrete types of carbon additives, then evaluating their effect when added to the negative electrodes within a traditional valve-regulated lead-acid battery design. The cycle life for the carbon modified cells was significantly larger than an unmodified control, with cells containing a mixture of graphitic carbon and carbon black yielding the greatest improvement. The carbons also impacted other electrochemical aspects of the battery (e.g., float current, capacity, etc.) as well as physical characteristics of the negative active mass, such as the specific surface area.« less

  8. Understanding Function and Performance of Carbon Additives in Lead-Acid Batteries

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Enos, D. G.; Ferreira, S. R.; Barkholtz, H. M.

    While the low cost and strong safety record of lead-acid batteries make them an appealing option compared to lithium-ion technologies for stationary storage, they can be rapidly degraded by the extended periods of high rate, partial state-of-charge operation required in such applications. Degradation occurs primarily through a process called hard sulfation, where large PbSO 4 crystals are formed on the negative battery plates, hindering charge acceptance and reducing battery capacity. Various researchers have found that the addition of some forms of excess carbon to the negative active mass in lead-acid batteries can mitigate hard sulfation, but the mechanism through whichmore » this is accomplished is unclear. In this work, the effect of carbon composition and morphology was explored by characterizing four discrete types of carbon additives, then evaluating their effect when added to the negative electrodes within a traditional valve-regulated lead-acid battery design. The cycle life for the carbon modified cells was significantly larger than an unmodified control, with cells containing a mixture of graphitic carbon and carbon black yielding the greatest improvement. The carbons also impacted other electrochemical aspects of the battery (e.g., float current, capacity, etc.) as well as physical characteristics of the negative active mass, such as the specific surface area.« less

  9. Microscopic Characterization of Individual Submicron Bubbles during the Layer-by-Layer Deposition: Towards Creating Smart Agents

    NASA Astrophysics Data System (ADS)

    Kato, Riku; Frusawa, Hiroshi

    2015-07-01

    We investigated the individual properties of various polyion-coated bubbles with a mean diameter ranging from 300 to 500 nm. Dark field microscopy allows one to track the individual particles of the submicron bubbles (SBs) encapsulated by the layer-by-layer (LbL) deposition of cationic and anionic polyelectrolytes (PEs). Our focus is on the two-step charge reversals of PE-SB complexes: the first is a reversal from negatively charged bare SBs with no PEs added to positive SBs encapsulated by polycations (monolayer deposition), and the second is overcharging into negatively charged PE-SB complexes due to the subsequent addition of polyanions (double-layer deposition). The details of these phenomena have been clarified through the analysis of a number of trajectories of various PE-SB complexes that experience either Brownian motion or electrophoresis. The contrasted results obtained from the analysis were as follows: an amount in excess of the stoichiometric ratio of the cationic polymers was required for the first charge-reversal, whereas the stoichiometric addition of the polyanions lead to the electrical neutralization of the PE-SB complex particles. The recovery of the stoichiometry in the double-layer deposition paves the way for fabricating multi-layered SBs encapsulated solely with anionic and cationic PEs, which provides a simple protocol to create smart agents for either drug delivery or ultrasound contrast imaging.

  10. Microscopic Characterization of Individual Submicron Bubbles during the Layer-by-Layer Deposition: Towards Creating Smart Agents.

    PubMed

    Kato, Riku; Frusawa, Hiroshi

    2015-07-08

    We investigated the individual properties of various polyion-coated bubbles with a mean diameter ranging from 300 to 500 nm. Dark field microscopy allows one to track the individual particles of the submicron bubbles (SBs) encapsulated by the layer-by-layer (LbL) deposition of cationic and anionic polyelectrolytes (PEs). Our focus is on the two-step charge reversals of PE-SB complexes: the first is a reversal from negatively charged bare SBs with no PEs added to positive SBs encapsulated by polycations (monolayer deposition), and the second is overcharging into negatively charged PE-SB complexes due to the subsequent addition of polyanions (double-layer deposition). The details of these phenomena have been clarified through the analysis of a number of trajectories of various PE-SB complexes that experience either Brownian motion or electrophoresis. The contrasted results obtained from the analysis were as follows: an amount in excess of the stoichiometric ratio of the cationic polymers was required for the first charge-reversal, whereas the stoichiometric addition of the polyanions lead to the electrical neutralization of the PE-SB complex particles. The recovery of the stoichiometry in the double-layer deposition paves the way for fabricating multi-layered SBs encapsulated solely with anionic and cationic PEs, which provides a simple protocol to create smart agents for either drug delivery or ultrasound contrast imaging.

  11. Evolution of Defect Structures and Deep Subgap States during Annealing of Amorphous In-Ga-Zn Oxide for Thin-Film Transistors

    NASA Astrophysics Data System (ADS)

    Jia, Junjun; Suko, Ayaka; Shigesato, Yuzo; Okajima, Toshihiro; Inoue, Keiko; Hosomi, Hiroyuki

    2018-01-01

    We investigate the evolution behavior of defect structures and the subgap states in In-Ga-Zn oxide (IGZO) films with increasing postannealing temperature by means of extended x-ray absorption fine-structure (EXAFS) measurements, positron annihilation lifetime spectroscopy (PALS), and cathodoluminescence (CL) spectroscopy, aiming to understand the relationship between defect structures and subgap states. EXAFS measurements reveal the varied oxygen coordination numbers around cations during postannealing and confirm two types of point defects, namely, excess oxygen around Ga atoms and oxygen deficiency around In and/or Zn atoms. PALS suggests the existence of cation-vacancy (VM )-related clusters with neutral or negative charge in both amorphous and polycrystalline IGZO films. CL spectra show a main emission band at approximately 1.85 eV for IGZO films, and a distinct shoulder located at about 2.15 eV for IGZO films postannealed above 600 °C . These two emission bands are assigned to a recombination between the electrons in the conduction band and/or in the shallow donor levels near the conduction band and the acceptors trapped above the valence-band maximum. The shallow donors are attributed to the oxygen deficiency, and the acceptors are thought to possibly arise from the excess oxygen or the VM-related clusters. These results open up an alternative route for understanding the device instability of amorphous IGZO-based thin-film transistors, especially the presence of the neutral or negatively charged VM-related clusters in amorphous IGZO films.

  12. Erzion interpretation of negative penetrating cosmic ray particles excess flux observed in bubble chamber "SKAT"

    NASA Astrophysics Data System (ADS)

    Bazhutov, Yu. N.

    2001-08-01

    It is discussed the interpretation of negative penetrating cosmic ray particles excess flux observed in bubble chamber "SKAT" for the momentum range P > P0 = 30 GeV/c by Erzions, hypothetical heavy stable penetrating hadrons, proposed to explain the anomalous vertical muons energy spectrum at small depth underground. Here it is shown that negative charge of p articles observed in "SKAT" is the same as predicted by theoretical Erzion model. The excess particles flux ( J ˜ 10-5 cm-2 s-1 sr-1 ) corresponds to the Erzion intensity observed by scintillation telescope in our previous experiment. The threshold momentum ( P0 ) and the track length threshold ( L0 = 50 cm of liquid BrF3C) are in good accordance with Erzion stop path as for the single charged particle with mass M ≅ 200 GeV/c2 . But to don't contradict with all previous charge ratio results for cosmic ray muons in 30 - 100 GeV/c momentum range it is necessary to propose for such particles the Solar sporadic origin taking to account that both Erzion observations were in the active Sun years (April 23,1979 & July, 1999). INTRODUCTION. 20 years ago to explain anomalous energy spectrum of vertical cosmic ray muons, observed at sea level and small depth underground (<100 m.w.e.) [1,2], it was proposed hypothesis of existing in cosmic rays new heavy stable penetrating hadrons [3]. From that time our experiments to search such particles were started [4,5,6]. Later the theoretical model U(1)xSUl(2)xSU r(2)xSU(3) of such particles (Erzions) has been created in framework of "mirror" models [7,8], which without contradictions to elementary particles Standard Model has explained large kind of another anomalous results in cosmic rays and nuclear physics [9-19]. At last after almost 20 years Erzions search they have been observed due to small vertical original scintillation telescope "Doch-4" [20,21,22]. The observed Erz ions mass was ME = (175+/-25) GeV/c2 and intensity at sea level - JE = (1.8+/-0.4)ṡ10-6 cm-2 sr-1 s-1 (at EE ≤ 6 GeV, PE ≤ 50 GeV/c2 ). To confirm such Erzion discovery it was undertook the attempt of Erzions search on one of the largest bubble chamber (BC) "SKAT", exposed 16 years (19761992) on the neutrino beam of Serpukhov Proton Accelerator.

  13. Positive and negative ion mode comparison for the determination of DNA/peptide noncovalent binding sites through the formation of "three-body" noncovalent fragment ions.

    PubMed

    Brahim, Bessem; Tabet, Jean-Claude; Alves, Sandra

    2018-02-01

    Gas-phase fragmentation of single strand DNA-peptide noncovalent complexes is investigated in positive and negative electrospray ionization modes.Collision-induced dissociation experiments, performed on the positively charged noncovalent complex precursor ions, have confirmed the trend previously observed in negative ion mode, i.e. a high stability of noncovalent complexes containing very basic peptidic residues (i.e. R > K) and acidic nucleotide units (i.e. Thy units), certainly incoming from the existence of salt bridge interactions. Independent of the ion polarity, stable noncovalent complex precursor ions were found to dissociate preferentially through covalent bond cleavages of the partners without disrupting noncovalent interactions. The resulting DNA fragment ions were found to be still noncovalently linked to the peptides. Additionally, the losses of an internal nucleic fragment producing "three-body" noncovalent fragment ions were also observed in both ion polarities, demonstrating the spectacular salt bridge interaction stability. The identical fragmentation patterns (regardless of the relative fragment ion abundances) observed in both polarities have shown a common location of salt bridge interaction certainly preserved from solution. Nonetheless, most abundant noncovalent fragment ions (and particularly three-body ones) are observed from positively charged noncovalent complexes. Therefore, we assume that, independent of the preexisting salt bridge interaction and zwitterion structures, multiple covalent bond cleavages from single-stranded DNA/peptide complexes rely on an excess of positive charges in both electrospray ionization ion polarities.

  14. Effects of organic silicon compounds as additives on charge-discharge cycling efficiencies of lithium in nonaqueous electrolytes for rechargeable lithium cells

    NASA Astrophysics Data System (ADS)

    Yanagisawa, Ryota; Endo, Hisayuki; Unno, Masafumi; Morimoto, Hideyuki; Tobishima, Shin-ichi

    2014-11-01

    Influence of mixing organic silicon compounds into 1 M (M: mol L-1) LiPF6-ethylene carbonate (EC)/ethylmethyl carbonate (EMC) (mixing volume ratio = 3:7) mixed solvent electrolytes on charge-discharge cycling efficiencies of lithium metal negative electrodes is examined. As organic silicon compounds, polyether-modified siloxanes with polyethylene oxide chains, chlorotrimethylsilane, tetraethoxysilane, cis-tetra [isobutyl (dimethylsiloxy)] cyclotetrasiloxane and cage-type silsesquioxane are investigated. Charge-discharge cycling tests of lithium are galvanostatically carried out using stainless steel working electrodes. Charge-discharge cycling efficiencies of lithium tend to improve by mixing organic silicon compounds. A cage-type silsesquioxane, octaphenyloctasilsesquioxane (Ph8T8) exhibits the highest cycling efficiency of approximately 80% with small mixing amount of 0.02 M Ph8T8. Mechanism of enhancement of lithium cycling efficiencies by mixing organic silicon compounds is considered to be due to the suppression of excess reduction of LiPF6-EC/EMC by lithium and the growth of surface film on lithium.

  15. Longitudinal Waves Drive the Solar Cycle

    NASA Astrophysics Data System (ADS)

    Wagner, Orvin

    2000-05-01

    In Physics Essays 12: 3-10 I explain the placement of the planets in terms of low velocity waves emitted by the sun. Evidence for the wave pulse generated near the center of the sun is indicated by the initial high latitude sunspots observed on the butterfly diagram. The wave pulse carries charge with it as observed for similar waves in plants (W-waves). For the first half cycle negative charge is carried to the surface of the sun where much of the wave pulse radiates a wave crest into space while the charge slowly redistributes itself. Meanwhile the next wave pulse carrying excess positive charge moves outward. Rotating charge determines the polarity of the sun's magnetic poles so they reverse as the pulse moves outward. The wave pulse, which interacts strongly with force fields, is guided by centripetal force and gravity so that the pulse comes out near the sun's equator. W-waves produce an automatic return wave in the vacuum so that standing waves are produced in the space around the sun providing a template for the formation and stabilization planets. W-waves are hypothesized to provide self organization for both the universe and life. See the

  16. 75 FR 48278 - Defense Federal Acquisition Regulation Supplement; Excessive Pass-Through Charges

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-08-10

    ... DEPARTMENT OF DEFENSE Defense Acquisition Regulations System 48 CFR Parts 215, 231, and 252 [DFARS Case 2006-D057] Defense Federal Acquisition Regulation Supplement; Excessive Pass-Through Charges AGENCY: Defense Acquisition Regulations System, Department of Defense (DoD). ACTION: Final rule. SUMMARY...

  17. Role of the Vascular Wall in Sodium Homeostasis and Salt Sensitivity

    PubMed Central

    Olde Engberink, Rik H.G.; Rorije, Nienke M.G.; Homan van der Heide, Jaap J.; van den Born, Bert-Jan H.

    2015-01-01

    Excessive sodium intake is associated with both hypertension and an increased risk of cardiovascular events, presumably because of an increase in extracellular volume. The extent to which sodium intake affects extracellular volume and BP varies considerably among individuals, discriminating subjects who are salt-sensitive from those who are salt-resistant. Recent experiments have shown that, other than regulation by the kidney, sodium homeostasis is also regulated by negatively charged glycosaminoglycans in the skin interstitium, where sodium is bound to glycosaminoglycans without commensurate effects on extracellular volume. The endothelial surface layer is a dynamic layer on the luminal side of the endothelium that is in continuous exchange with flowing blood. Because negatively charged glycosaminoglycans are abundantly present in this layer, it may act as an intravascular buffer compartment that allows sodium to be transiently stored. This review focuses on the putative role of the endothelial surface layer as a contributor to salt sensitivity, the consequences of a perturbed endothelial surface layer on sodium homeostasis, and the endothelial surface layer as a possible target for the treatment of hypertension and an expanded extracellular volume. PMID:25294232

  18. Complex coacervation of supercharged proteins with polyelectrolytes.

    PubMed

    Obermeyer, Allie C; Mills, Carolyn E; Dong, Xue-Hui; Flores, Romeo J; Olsen, Bradley D

    2016-04-21

    Complexation of proteins with polyelectrolytes or block copolymers can lead to phase separation to generate a coacervate phase or self-assembly of coacervate core micelles. However, many proteins do not coacervate at conditions near neutral pH and physiological ionic strength. Here, protein supercharging is used to systematically explore the effect of protein charge on the complex coacervation with polycations. Four model proteins were anionically supercharged to varying degrees as quantified by mass spectrometry. Proteins phase separated with strong polycations when the ratio of negatively charged residues to positively charged residues on the protein (α) was greater than 1.1-1.2. Efficient partitioning of the protein into the coacervate phase required larger α (1.5-2.0). The preferred charge ratio for coacervation was shifted away from charge symmetry for three of the four model proteins and indicated an excess of positive charge in the coacervate phase. The composition of protein and polymer in the coacervate phase was determined using fluorescently labeled components, revealing that several of the coacervates likely have both induced charging and a macromolecular charge imbalance. The model proteins were also encapsulated in complex coacervate core micelles and micelles formed when the protein charge ratio α was greater than 1.3-1.4. Small angle neutron scattering and transmission electron microscopy showed that the micelles were spherical. The stability of the coacervate phase in both the bulk and micelles improved to increased ionic strength as the net charge on the protein increased. The micelles were also stable to dehydration and elevated temperatures.

  19. 47 CFR 69.157 - Line port costs in excess of basic, analog service.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 47 Telecommunication 3 2010-10-01 2010-10-01 false Line port costs in excess of basic, analog service. 69.157 Section 69.157 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) COMMON CARRIER SERVICES (CONTINUED) ACCESS CHARGES Computation of Charges for Price Cap Local Exchange Carriers...

  20. Solvation of excess electrons trapped in charge pockets on molecular surfaces

    NASA Astrophysics Data System (ADS)

    Jalbout, Abraham F.

    This work considers the ability of hydrogen fluoride (HF) to solvate excess electrons located on cyclic hydrocarbon surfaces. The principle applied involves the formation of systems in which excess electrons can be stabilized not only on concentrated molecular surface charge pockets but also by HF. Recent studies have shown that OH groups can form stable hydrogen-bonded networks on one side of a hydrocarbon surface (i.e. cyclohexane sheets), at the same time, the hydrogen atoms on the opposite side of this surface form a pocket of positive charge can attract the excess electron. This density can be further stabilized by the addition of an HF molecule that can form an 'anion with an internally solvated electron' (AISE) state. These systems are shown to be stable with respect to vertical electron detachment (VDE).

  1. Dependence of charge transfer phenomena during solid-air two-phase flow on particle disperser

    NASA Astrophysics Data System (ADS)

    Tanoue, Ken-ichiro; Suedomi, Yuuki; Honda, Hirotaka; Furutani, Satoshi; Nishimura, Tatsuo; Masuda, Hiroaki

    2012-12-01

    An experimental investigation of the tribo-electrification of particles has been conducted during solid-air two-phase turbulent flow. The current induced in a metal plate by the impact of polymethylmethacrylate (PMMA) particles in a high-speed air flow was measured for two different plate materials. The results indicated that the contact potential difference between the particles and a stainless steel plate was positive, while for a nickel plate it was negative. These results agreed with theoretical contact charge transfer even if not only the particle size but also the kind of metal plate was changed. The specific charge of the PMMA particles during solid-air two-phase flow using an ejector, a stainless steel branch pipe, and a stainless steel straight pipe was measured using a Faraday cage. Although the charge was negative in the ejector, the particles had a positive specific charge at the outlet of the branch pipe, and this positive charge increased in the straight pipe. The charge decay along the flow direction could be reproduced by the charging and relaxation theory. However, the proportional coefficients in the theory changed with the particle size and air velocity. Therefore, an unexpected charge transfer occurred between the ejector and the branch pipe, which could not be explained solely by the contact potential difference. In the ejector, an electrical current in air might have been produced by self-discharge of particles with excess charge between the nickel diffuser in the ejector and the stainless steel nozzle or the stainless steel pipe due to a reversal in the contact potential difference between the PMMA and the stainless steel. The sign of the current depended on the particle size, possibly because the position where the particles impacted depended on their size. When dual coaxial glass pipes were used as a particle disperser, the specific charge of the PMMA particles became more positive along the particle flow direction due to the contact potential difference between the PMMA and the stainless steel. Furthermore, the current in air using the dual coaxial glass pipes was less than that using the ejector.

  2. 18 CFR 35.19a - Refund requirements under suspension orders.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... percent simple interest per annum on all excessive rates or charges held prior to October 10, 1974; (ii) At a rate of nine percent simple interest per annum on all excessive rates or charges held between... justified, together with interest as required in paragraph (a)(2) of this section. (2) Interest shall be...

  3. Nonideal mixing of phosphatidylserine and phosphatidylcholine in the fluid lamellar phase.

    PubMed Central

    Huang, J; Swanson, J E; Dibble, A R; Hinderliter, A K; Feigenson, G W

    1993-01-01

    The mixing of phosphatidylserine (PS) and phosphatidylcholine (PC) in fluid bilayer model membranes was studied by measuring binding of aqueous Ca2+ ions. The measured [Ca2+]aq was used to derive the activity coefficient for PS, gamma PS, in the lipid mixture. For (16:0, 18:1) PS in binary mixtures with either (16:0, 18:1)PC, (14:1, 14:1)PC, or (18:1, 18:1)PC, gamma PS > 1; i.e., mixing is nonideal, with PS and PC clustered rather than randomly distributed, despite the electrostatic repulsion between PS headgroups. To understand better this mixing behavior, Monte Carlo simulations of the PS/PC distributions were performed, using Kawasaki relaxation. The excess energy was divided into an electrostatic term Uel and one adjustable term including all other nonideal energy contributions, delta Em. Uel was calculated using a discrete charge theory. Kirkwood's coupling parameter method was used to calculate the excess free energy of mixing, delta GEmix, hence In gamma PS,calc. The values of In gamma PS,calc were equalized by adjusting delta Em in order to find the simulated PS/PC distribution that corresponded to the experimental results. We were thus able to compare the smeared charge calculation of [Ca2+]surf with a calculation ("masked evaluation method") that recognized clustering of the negatively charged PS: clustering was found to have a modest effect on [Ca2+]surf, relative to the smeared charge model. Even though both PS and PC tend to cluster, the long-range nature of the electrostatic repulsion reduces the extent of PS clustering at low PS mole fraction compared to PC clustering at an equivalent low PC mole fraction. PMID:8457667

  4. Nonideal mixing of phosphatidylserine and phosphatidylcholine in the fluid lamellar phase.

    PubMed

    Huang, J; Swanson, J E; Dibble, A R; Hinderliter, A K; Feigenson, G W

    1993-02-01

    The mixing of phosphatidylserine (PS) and phosphatidylcholine (PC) in fluid bilayer model membranes was studied by measuring binding of aqueous Ca2+ ions. The measured [Ca2+]aq was used to derive the activity coefficient for PS, gamma PS, in the lipid mixture. For (16:0, 18:1) PS in binary mixtures with either (16:0, 18:1)PC, (14:1, 14:1)PC, or (18:1, 18:1)PC, gamma PS > 1; i.e., mixing is nonideal, with PS and PC clustered rather than randomly distributed, despite the electrostatic repulsion between PS headgroups. To understand better this mixing behavior, Monte Carlo simulations of the PS/PC distributions were performed, using Kawasaki relaxation. The excess energy was divided into an electrostatic term Uel and one adjustable term including all other nonideal energy contributions, delta Em. Uel was calculated using a discrete charge theory. Kirkwood's coupling parameter method was used to calculate the excess free energy of mixing, delta GEmix, hence In gamma PS,calc. The values of In gamma PS,calc were equalized by adjusting delta Em in order to find the simulated PS/PC distribution that corresponded to the experimental results. We were thus able to compare the smeared charge calculation of [Ca2+]surf with a calculation ("masked evaluation method") that recognized clustering of the negatively charged PS: clustering was found to have a modest effect on [Ca2+]surf, relative to the smeared charge model. Even though both PS and PC tend to cluster, the long-range nature of the electrostatic repulsion reduces the extent of PS clustering at low PS mole fraction compared to PC clustering at an equivalent low PC mole fraction.

  5. Two barriers for sodium in vascular endothelium?

    PubMed Central

    Oberleithner, Hans

    2012-01-01

    Vascular endothelium plays a key role in blood pressure regulation. Recently, it has been shown that a 5% increase of plasma sodium concentration (sodium excess) stiffens endothelial cells by about 25%, leading to cellular dysfunction. Surface measurements demonstrated that the endothelial glycocalyx (eGC), an anionic biopolymer, deteriorates when sodium is elevated. In view of these results, a two-barrier model for sodium exiting the circulation across the endothelium is suggested. The first sodium barrier is the eGC which selectively buffers sodium ions with its negatively charged prote-oglycans.The second sodium barrier is the endothelial plasma membrane which contains sodium channels. Sodium excess, in the presence of aldosterone, leads to eGC break-down and, in parallel, to an up-regulation of plasma membrane sodium channels. The following hypothesis is postulated: Sodium excess increases vascular sodium permeability. Under such con-ditions (e.g. high-sodium diet), day-by-day ingested sodium, instead of being readily buffered by the eGC and then rapidly excreted by the kidneys, is distributed in the whole body before being finally excreted. Gradually, the sodium overload damages the organism. PMID:22471931

  6. Electrospray ionization of uranyl-citrate complexes

    NASA Astrophysics Data System (ADS)

    Somogyi, Árpád; Pasilis, Sofie P.; Pemberton, Jeanne E.

    2007-09-01

    Results presented here demonstrate the usefulness of electrospray ionization and gas-phase ion-molecule reactions to predict structural and electronic differences in complex inorganic ions. Electrospray ionization of uranyl citrate solutions generates positively and negatively charged ions that participate in further ion-molecule reactions in 3D ion trap and FT-ICR mass analyzers. Most ions observed are derived from the major solution uranyl-citrate complexes and involve species of {(UO2)2Cit2}2-, (UO2)3Cit2, and {(UO2)3Cit3}3-, where Cit indicates the citrate trianion, C6H5O73-. In a 3D ion trap operated at relatively high pressure, complex adducts containing solvent molecules, alkali and ammonium cations, and nitrate or chloride anions are dominant, and proton/alkali cation (Na+, K+) exchange is observed for up to six exchangeable protons in an excess of alkali cations. Adduct formation in a FT-ICR cell that is operated at lower pressures is less dominant, and direct detection of positive and negative ions of the major solution complexes is possible. Multiply charged ions are also detected, suggesting the presence of uranium in different oxidation states. Changes in uranium oxidation state are detected by He-CID and SORI-CID fragmentation, and certain fragments undergo association reactions in trapping analyzers, forming "exotic" species such as [(UO2)4O3]-, [(UO2)4O4]-, and [(UO2)4O5]-. Ion-molecule reactions with D2O in the FT-ICR cell indicate substantial differences in H/D exchange rate and D2O accommodation for different ion structures and charge states. Most notably, the positively charged ions [H2(UO2)2Cit2(H)]+ and [(UO2)2(Cit)]+ accommodate two and three D2O molecules, respectively, which reflects well the structural differences, i.e., tighter uranyl-citrate coordination in the former ion than in the latter. The corresponding negatively charged ions accommodate zero or two D2O molecules, which can be rationalized using suggested solution phase structures and charge state distributions.

  7. Observation of excess flux for negative cosmic ray penetrating particles in bubble chamber "SKAT" for momentum range (30GeV/c

    NASA Astrophysics Data System (ADS)

    Bazhutov, Yu. N.; Baranov, D. S.

    2001-08-01

    There are presented the first results of the new heavy stable cosmic ray particles search in the bubble chamber "SKAT" (450 x 160 x 90 cm3 ), which was exposed in the neutrino beam of Serpukhov Accelerator during 1976 - 1992 years and was viewed along the horizontal direction so as the magnet field direction (MDM > 150 GeV/c). From looking over 1,270 stills (1 roll for April 23, 1979) it was selected 757 tracks of cosmic ray particles with zenith angle θ < 45°, track length - L > 50 cm and momentum P>2.0GeV/c. From this events there were constructed momentum spectrums for both negative and positive vertical cosmic ray penetrating particles in the (2.0 - 126) GeV/c range and calculated their charge ratio. For positive particles the momentum spectrum has normal shape in all studied range the same as for negative particles but only for momentum range (2.0 - 32) GeV/c and charge ratio for this range is normal and the same as for cosmic muons. But for momentum P>32GeV/c it was observed negative particles excess flux (~10-5 cm-2 s-1 sr-1 ) with changed charge ratio - R = 0.62 +/0.18 (˜>3.5σ) for momentum range (32GeV/c3σ) and for momentum range (3.6GeV/c107 cm2 ṡsṡsr); 2) the installation place must be on the Earth surface or small underground (< 100 m.w.e.); 3) it is desirable to use track detector for event and particle charge viewing. One of the largest Bubble Chamber "SKAT" (BC), operated from 1976 to 1992 on the Serpukhov Accelerator neutrino beam had satisfied to all these demands. Its operation on the neutrino beam could provide a small background from Accelerator fo r our researches. Accumulated ~ 4 x 2,000,000 stills inside ~ 4 x 1660 rolls during this long period were conserved until now and were ready to analysis. The large Bubble Chamber (450 x 160 x 90 cm3 ) had been placed in greatest magnetic field (17 kG) horizontally directed so as coaxial to it view of 4 stereo photo chambers. So near vertical penetrating cosmic rays could be registered the same as near horizontal neutrino beam events. Full "SKAT" exposition is S-T ~ 4ṡ109 cm2 ṡsṡsr , that is rather more demanded one. It provides us for charge and momentum (MDM > 150 GeV/c) measurements. BC had been placed on the Earth surface, but had large magnetic iron screen (d ~ 2500 g/cm2 = 25m.w.e., Fig.1).

  8. Measurements and theoretical interpretation of points of zero charge/potential of BSA protein.

    PubMed

    Salis, Andrea; Boström, Mathias; Medda, Luca; Cugia, Francesca; Barse, Brajesh; Parsons, Drew F; Ninham, Barry W; Monduzzi, Maura

    2011-09-20

    The points of zero charge/potential of proteins depend not only on pH but also on how they are measured. They depend also on background salt solution type and concentration. The protein isoelectric point (IEP) is determined by electrokinetical measurements, whereas the isoionic point (IIP) is determined by potentiometric titrations. Here we use potentiometric titration and zeta potential (ζ) measurements at different NaCl concentrations to study systematically the effect of ionic strength on the IEP and IIP of bovine serum albumin (BSA) aqueous solutions. It is found that high ionic strengths produce a shift of both points toward lower (IEP) and higher (IIP) pH values. This result was already reported more than 60 years ago. At that time, the only available theory was the purely electrostatic Debye-Hückel theory. It was not able to predict the opposite trends of IIP and IEP with ionic strength increase. Here, we extend that theory to admit both electrostatic and nonelectrostatic (NES) dispersion interactions. The use of a modified Poisson-Boltzmann equation for a simple model system (a charge regulated spherical colloidal particle in NaCl salt solutions), that includes these ion specific interactions, allows us to explain the opposite trends observed for isoelectric point (zero zeta potential) and isoionic point (zero protein charge) of BSA. At higher concentrations, an excess of the anion (with stronger NES interactions than the cation) is adsorbed at the surface due to an attractive ionic NES potential. This makes the potential relatively more negative. Consequently, the IEP is pushed toward lower pH. But the charge regulation condition means that the surface charge becomes relatively more positive as the surface potential becomes more negative. Consequently, the IIP (measuring charge) shifts toward higher pH as concentration increases, in the opposite direction from the IEP (measuring potential). © 2011 American Chemical Society

  9. Effective Electrostatic Interactions Between Two Overall Neutral Surfaces with Quenched Charge Heterogeneity Over Atomic Length Scale

    NASA Astrophysics Data System (ADS)

    Zhou, S.

    2017-12-01

    Using Monte Carlo results as a reference, a classical density functional theory ( CDFT) is shown to reliably predict the forces between two heterogeneously charged surfaces immersed in an electrolyte solution, whereas the Poisson-Boltzmann ( PB) theory is demonstrated to deteriorate obviously for the same system even if the system parameters considered fall within the validity range of the PB theory in the homogeneously charged surfaces. By applying the tested CDFT, we study the effective electrostatic potential of mean force ( EPMF) between two face-face planar and hard surfaces of zero net charge on which positive and negative charges are separated and considered to present as discontinuous spots on the inside edges of the two surfaces. Main conclusions are summarized as follows: (i) strength of the EPMF in the surface charge separation case is very sensitively and positively correlated with the surface charge separation level and valency of the salt ion. Particularly, the charge separation level and the salt ion valency have a synergistic effect, which makes high limit of the EPMF strength in the surface charge separation case significantly go beyond that of the ideal homogeneously charged surface counterpart at average surface charge density similar to the average surface positive or negative charge density in the charge separation case. (ii) The surface charge distribution patterns mainly influence sign of the EPMF: symmetrical and asymmetrical patterns induce repulsive and attractive (at small distances) EPMF, respectively; but with low valency salt ions and low charge separation level the opposite may be the case. With simultaneous presence of both higher valency cation and anion, the EPMF can be repulsive at intermediate distances for asymmetrical patterns. (iii) Salt ion size has a significant impact, which makes the EPMF tend to become more and more repulsive with the ion diameter regardless of the surface charge distribution patterns and the valency of the salt ion; whereas if the 1:1 type electrolyte and the symmetrical patterns are considered, then the opposite may be the case. All of these findings can be explained self-consistently from several perspectives: an excess adsorption of the salt ions (induced by the surface charge separation) serving to raise the osmotic pressure between the plates, configuration fine-tuning in the thinner ion adsorption layer driven by the energy decrease principle, direct Coulombic interactions operating between charged objects on the two face-to-face plates involved, and net charge strength in the ion adsorption layer responsible for the net electrostatic repulsion.

  10. The Flexible Faraday Cage

    NASA Astrophysics Data System (ADS)

    Gluck, Paul

    2004-03-01

    The Faraday ice-pail experiment is performed when studying the distribution of charges in conductors: Inside a hollow conductor the net charge is zero, and any excess charge resides on the outside surface.

  11. Polarized radio emission from extensive air showers measured with LOFAR

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Schellart, P.; Buitink, S.; Corstanje, A.

    2014-10-01

    We present LOFAR measurements of radio emission from extensive air showers. We find that this emission is strongly polarized, with a median degree of polarization of nearly 99%, and that the angle between the polarization direction of the electric field and the Lorentz force acting on the particles, depends on the observer location in the shower plane. This can be understood as a superposition of the radially polarized charge-excess emission mechanism, first proposed by Askaryan and the geomagnetic emission mechanism proposed by Kahn and Lerche. We calculate the relative strengths of both contributions, as quantified by the charge-excess fraction, formore » 163 individual air showers. We find that the measured charge-excess fraction is higher for air showers arriving from closer to the zenith. Furthermore, the measured charge-excess fraction also increases with increasing observer distance from the air shower symmetry axis. The measured values range from (3.3± 1.0)% for very inclined air showers at 25 m to (20.3± 1.3)% for almost vertical showers at 225 m. Both dependencies are in qualitative agreement with theoretical predictions.« less

  12. Effect of drug Piper nigrum on magnesium chloride at varying concentration and temperature through ultrasonic method: A thermoacoustic study

    NASA Astrophysics Data System (ADS)

    Nalle, Pallavi B.; Deshmukh, S. S.; Dorik, R. G.; Jadhav, K. M.

    2016-12-01

    The ultrasonic velocity (U), density (ρ), and viscosity (η) of an ethanolic extract of drug Piper nigrum with MgCl2 (metal ions) have been measured as a function of the number of moles n = (0.7009, 1.4018, 2.1027, 2.8036 and 3.5045) at 303.15, 308.15, 313.15 and 318.15 K temperature. Various thermoacoustic and their excess values such as adiabatic compressibilities (β), intermolecular free lengths (Lf), excess adiabatic compressibility (βE), excess intermolecular free length (?) have been computed using values of ultrasonic velocity (U), density (ρ), and viscosity (η). The excess values of ultrasonic velocity, specific acoustic impedance are positive, whereas isentropic compressibility and intermolecular free lengths are negative over the entire composition range of MgCl2 + P. nigrum which indicates the presence of specific interactions between unlike molecules. Molecular association is reflected by ultrasonic investigation. This may be interpreted due to the of complex formation. The chemical interaction may involve the association due to the solute-solvent and ion-solvent interaction and due to the formation of charge-transfer complexes, which is useful to understand the mechanism of their metabolism in living systems. The results obtained from these studies are helpful for pharmacological applications of drugs, transport of drugs across biological membranes.

  13. Electrostatically driven immobilization of peptides onto (Maleic anhydride-alt-methyl vinyl ether) copolymers in aqueous media.

    PubMed

    Ladavière, C; Lorenzo, C; Elaïssari, A; Mandrand, B; Delair, T

    2000-01-01

    The covalent immobilization of a model peptide onto the MAMVE copolymer, via the formation of amide bonds, occurred in moderate yields in aqueous conditions. The improvement of the grafting reaction was achieved by adding at the amino terminus of the model peptide a sequence (tag) of three positively charged amino acids, lysine or arginine, and by taking profit of electrostatic attractive interactions between the negatively charged copolymer and the tagged peptides. The arginine tag was more efficient than the lysine tag for enhancing the immobilization reaction, proving that the effect was due to an electrostic driving force. On the basis of these results, a tentative mechanism is discussed, and Scatchard plots pointed out two regimes of binding. With the first, at low polymer load (up to 50% of saturation for a lysine tag and 60-70% for an arginine tag), the binding occurred with a positive cooperative effect, the already bound peptide participating to the binding of others. A second one for higher coverages, for which the binding occurred with a negative cooperativity, and saturation was reached in the presence of a large excess of peptide.

  14. Mass spectrometer with electron source for reducing space charge effects in sample beam

    DOEpatents

    Houk, Robert S.; Praphairaksit, Narong

    2003-10-14

    A mass spectrometer includes an ion source which generates a beam including positive ions, a sampling interface which extracts a portion of the beam from the ion source to form a sample beam that travels along a path and has an excess of positive ions over at least part of the path, thereby causing space charge effects to occur in the sample beam due to the excess of positive ions in the sample beam, an electron source which adds electrons to the sample beam to reduce space charge repulsion between the positive ions in the sample beam, thereby reducing the space charge effects in the sample beam and producing a sample beam having reduced space charge effects, and a mass analyzer which analyzes the sample beam having reduced space charge effects.

  15. Is the CMS e e j j excess a hint for light supersymmetry?

    NASA Astrophysics Data System (ADS)

    Krauss, Manuel E.; Porod, Werner

    2015-09-01

    We discuss the impact of additional two-body decays of the right-handed neutrino into a light charged Higgs state on the dilepton plus dijet cross sections from resonant W' production. We consider in particular a supersymmetric left-right symmetric model which predicts such a light charged Higgs boson. We demonstrate that the e e j j excess as measured by CMS can be explained best if the W' also has decay modes into Higgsino-like charginos and neutralinos with masses of a few hundred GeV. Provided that this excess is confirmed, the model predicts also one right-handed neutrino with a mass below 200 GeV as well as a doubly charged Higgs boson which should be discovered at the LHC in the near future.

  16. Penetration and release studies of positively and negatively charged nanoemulsions--is there a benefit of the positive charge?

    PubMed

    Baspinar, Yücel; Borchert, Hans-Hubert

    2012-07-01

    The surface of all tissues, including the stratum corneum, carries a negative charge. Following that fact it is assumed that a positively charged topical formulation could lead to an enhanced penetration because of an increased interaction with the negative charge of the membrane. The intention of this study is to prove an enhanced penetration of a positively charged nanoemulsion compared to a negatively charged nanoemulsion, both containing prednicarbate. The release and penetration of these nanoemulsions, produced with the high pressure homogenization method, were investigated. Regarding these results reveals that the release of the negatively charged formulation is higher compared to the positively charged nanoemulsion, while the penetration of the positively charged nanoemulsion is enhanced compared to the negatively charged formulation. The results of the investigated positively charged nanoemulsion containing prednicarbate show that its topical use could be advantageous for the therapy of atopic dermatitis, especially regarding phytosphingosine, which was responsible for the positive charge. Copyright © 2012 Elsevier B.V. All rights reserved.

  17. 41 CFR 302-7.201 - Is temporary storage in excess of authorized limits and excess valuation of goods and services...

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... excess of authorized limits and excess valuation of goods and services payable at Government expense? 302... Government expense? No, charges for excess weight, valuation above the minimum amount, and services obtained... HOUSEHOLD GOODS AND PROFESSIONAL BOOKS, PAPERS, AND EQUIPMENT (PBP&E) Actual Expense Method § 302-7.201 Is...

  18. 41 CFR 302-7.201 - Is temporary storage in excess of authorized limits and excess valuation of goods and services...

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... excess of authorized limits and excess valuation of goods and services payable at Government expense? 302... Government expense? No, charges for excess weight, valuation above the minimum amount, and services obtained... HOUSEHOLD GOODS AND PROFESSIONAL BOOKS, PAPERS, AND EQUIPMENT (PBP&E) Actual Expense Method § 302-7.201 Is...

  19. Influence of ionic strength and surfactant concentration on electrostatic surfacial assembly of cetyltrimethylammonium bromide-capped gold nanorods on fully immersed glass.

    PubMed

    Ferhan, Abdul Rahim; Guo, Longhua; Kim, Dong-Hwan

    2010-07-20

    The effect of ionic strength as well as surfactant concentration on the surface assembly of cetyltrimethylammonium bromide (CTAB)-capped gold nanorods (GNRs) has been studied. Glass substrates were modified to yield a net negative charge through electrostatic coating of polystyrenesulfonate (PSS) over a self-assembled monolayer (SAM) of positively charged aminopropyltriethoxysilane (APTS). The substrates were then fully immersed in GNR solutions at different CTAB concentrations and ionic strengths. Under slightly excess CTAB concentrations, it was observed that the density of GNRs immobilized on a substrate was predictably tunable through the adjustment of NaCl concentration over a wide range. Motivated by the experimental observation, we hypothesize that electrostatic shielding of charges around the GNRs affects the density of GNR immobilization. This model ultimately explains that at moderate to high CTAB concentrations a second electrostatic shielding effect contributed by excess CTAB molecules occurs, resulting in a parabolic trend of nanorod surface density when ionic strength is continually increased. In contrast, at a low CTAB concentration, the effect of ionic strength becomes much less significant due to insufficient CTAB molecules to provide for the second electrostatic shielding effect. The tunability of electrostatic-based surface assembly of GNRs enables the attainment of a dense surface assembly of nanorods without significant removal of CTAB or any other substituted stabilizing agent, both of which could compromise the stability and morphology of GNRs in solution. An additional study performed to investigate the robustness of such electrostatic-based surface assembly also proved its reliability to be used as biosensing platforms.

  20. 20 CFR 404.435 - Excess earnings; months to which excess earnings can or cannot be charged; grace year defined.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... be charged; grace year defined. (a) Monthly benefits payable. We will not reduce your benefits on... your grace year (see paragraph (b) of this section). A non-service month is any month in which you... reason of having a child in his or her care), or to mother's or father's benefits is entitled to a...

  1. 20 CFR 404.435 - Excess earnings; months to which excess earnings can or cannot be charged; grace year defined.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... be charged; grace year defined. (a) Monthly benefits payable. We will not reduce your benefits on... your grace year (see paragraph (b) of this section). A non-service month is any month in which you... reason of having a child in his or her care), or to mother's or father's benefits is entitled to a...

  2. 20 CFR 404.435 - Excess earnings; months to which excess earnings can or cannot be charged; grace year defined.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... be charged; grace year defined. (a) Monthly benefits payable. We will not reduce your benefits on... your grace year (see paragraph (b) of this section). A non-service month is any month in which you... reason of having a child in his or her care), or to mother's or father's benefits is entitled to a...

  3. 10 CFR 904.10 - Excess energy.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 10 Energy 4 2011-01-01 2011-01-01 false Excess energy. 904.10 Section 904.10 Energy DEPARTMENT OF ENERGY GENERAL REGULATIONS FOR THE CHARGES FOR THE SALE OF POWER FROM THE BOULDER CANYON PROJECT Power Marketing § 904.10 Excess energy. (a) If excess Energy is determined by the United States to be available...

  4. 10 CFR 904.10 - Excess energy.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 10 Energy 4 2014-01-01 2014-01-01 false Excess energy. 904.10 Section 904.10 Energy DEPARTMENT OF ENERGY GENERAL REGULATIONS FOR THE CHARGES FOR THE SALE OF POWER FROM THE BOULDER CANYON PROJECT Power Marketing § 904.10 Excess energy. (a) If excess Energy is determined by the United States to be available...

  5. 10 CFR 904.10 - Excess energy.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 10 Energy 4 2012-01-01 2012-01-01 false Excess energy. 904.10 Section 904.10 Energy DEPARTMENT OF ENERGY GENERAL REGULATIONS FOR THE CHARGES FOR THE SALE OF POWER FROM THE BOULDER CANYON PROJECT Power Marketing § 904.10 Excess energy. (a) If excess Energy is determined by the United States to be available...

  6. 10 CFR 904.10 - Excess energy.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 10 Energy 4 2013-01-01 2013-01-01 false Excess energy. 904.10 Section 904.10 Energy DEPARTMENT OF ENERGY GENERAL REGULATIONS FOR THE CHARGES FOR THE SALE OF POWER FROM THE BOULDER CANYON PROJECT Power Marketing § 904.10 Excess energy. (a) If excess Energy is determined by the United States to be available...

  7. 10 CFR 904.10 - Excess energy.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 10 Energy 4 2010-01-01 2010-01-01 false Excess energy. 904.10 Section 904.10 Energy DEPARTMENT OF ENERGY GENERAL REGULATIONS FOR THE CHARGES FOR THE SALE OF POWER FROM THE BOULDER CANYON PROJECT Power Marketing § 904.10 Excess energy. (a) If excess Energy is determined by the United States to be available...

  8. Internal transitions of neutral (X) and negatively charged (X(-)) magneto-excitons investigated by optically detected resonance (ODR) spectroscopy

    NASA Astrophysics Data System (ADS)

    Nickel, Hans Andreas

    Optically detected resonance (ODR) spectroscopy, an experimental technique combining spectroscopy in the far-infrared and visible regimes of the spectrum, has been applied to non-intentionally- and modulation-doped, quasi-2D GaAs/AlGaAs heterostructures at low temperatures and high magnetic fields to study internal transitions of neutral (X) and negatively charged (X--) magneto-excitons. In quasi-2D GaAs/AlGaAs heterostructures with a low density of free carriers, such as undoped multiple-quantum-wells, the ground state of optical excitations is the neutral exciton. This hydrogenic system was studied by far-infrared ODR spectroscopy, and internal excitonic transitions (IETs) 1s → np+/- from the ground state (1s) to excited states (np+/-) were found. Three samples of different well widths were studied systematically, and the behavior of the observed transitions as a function of the sample well-width was as expected. A predicted consequence of an inherent symmetry to the system was verified experimentally for the first time by the simultaneous observation of IETs and electron and hole cyclotron resonance in one sample in one experiment. In addition, it was also found, that the observability of IETs is destroyed as soon as there is a sign of X---recombination in the photoluminescence spectrum. In quantum wells with a small number of excess electrons the ground state of the system under optical excitation is the negatively charged exciton, X--. This mobile system of a hole binding two electrons differs significantly in certain aspects from its immobile impurity analogue, the negatively charged donor ion D-- . The mobility of the charged complex is tied to a hidden symmetry of magnetic translations, which leads to a new selection rule, that forbids X-- bound-to-bound transitions, in contrast to the D -- system, in which these transitions are dominant. In this dissertation, several samples that show X-- recombination in photoluminescence measurements were studied with ODR spectroscopy, and internal singlet and triplet bound-to-continuum transitions were observed for the first time. The experimental results were found to agree well with theoretical numerical calculations. Furthermore, the theoretical predictions were verified: no bound-to-bound X-- internal transition was observed.

  9. Conversion of multiple analyte cation types to a single analyte anion type via ion/ion charge inversion.

    PubMed

    Hassell, Kerry M; LeBlanc, Yves; McLuckey, Scott A

    2009-11-01

    Charge inversion ion/ion reactions can convert several cation types associated with a single analyte molecule to a single anion type for subsequent mass analysis. Specifically, analyte ions present with one of a variety of cationizing agents, such as an excess proton, excess sodium ion, or excess potassium ion, can all be converted to the deprotonated molecule, provided that a stable anion can be generated for the analyte. Multiply deprotonated species that are capable of exchanging a proton for a metal ion serve as the reagent anions for the reaction. This process is demonstrated here for warfarin and for a glutathione conjugate. Examples for several other glutathione conjugates are provided as supplementary material to demonstrate the generality of the reaction. In the case of glutathione conjugates, multiple metal ions can be associated with the singly-charged analyte due to the presence of two carboxylate groups. The charge inversion reaction involves the removal of the excess cationizing agent, as well as any metal ions associated with anionic groups to yield a singly deprotonated analyte molecule. The ability to convert multiple cation types to a single anion type is analytically desirable in cases in which the analyte signal is distributed among several cation types, as is common in the electrospray ionization of solutions with relatively high salt contents. For analyte species that undergo efficient charge inversion, such as glutathione conjugates, there is the additional potential advantage for significantly improved signal-to-noise ratios when species that give rise to 'chemical noise' in the positive ion spectrum do not undergo efficient charge inversion.

  10. Photoelectron spectroscopy of color centers in negatively charged cesium iodide nanocrystals

    NASA Astrophysics Data System (ADS)

    Sarkas, Harry W.; Kidder, Linda H.; Bowen, Kit H.

    1995-01-01

    We present the photoelectron spectra of negatively charged cesium iodide nanocrystals recorded using 2.540 eV photons. The species examined were produced using an inert gas condensation cluster ion source, and they ranged in size from (CsI)-n=13 to nanocrystal anions comprised of 330 atoms. Nanocrystals showing two distinct types of photoemission behavior were observed. For (CsI)-n=13 and (CsI)-n=36-165, a plot of cluster anion photodetachment threshold energies vs n-1/3 gives a straight line extrapolating (at n-1/3=0, i.e., n=∞) to 2.2 eV, the photoelectric threshold energy for F centers in bulk cesium iodide. The linear extrapolation of the cluster anion data to the corresponding bulk property implies that the electron localization in these gas-phase nanocrystals is qualitatively similar to that of F centers in extended alkali halide crystals. These negatively charged cesium iodide nanocrystals are thus shown to support embryonic forms of F centers, which mature with increasing cluster size toward condensed phase impurity centers. Under an alternative set of source conditions, nanocrystals were produced which showed significantly lower photodetachment thresholds than the aforementioned F-center cluster anions. For these species, containing 83-131 atoms, a plot of their cluster anion photodetachment threshold energies versus n-1/3 gives a straight line which extrapolates to 1.4 eV. This value is in accord with the expected photoelectric threshold energy for F' centers in bulk cesium iodide, i.e., color centers with two excess electrons in a single defect site. These nanocrystals are interpreted to be the embryonic F'-center containing species, Cs(CsI)-n=41-65.

  11. What Protein Charging (and Supercharging) Reveal about the Mechanism of Electrospray Ionization

    PubMed Central

    Loo, Rachel R. Ogorzalek; Lakshmanan, Rajeswari

    2014-01-01

    Understanding the charging mechanism of electrospray ionization is central to overcoming shortcomings such as ion suppression or limited dynamic range and explaining phenomena such as supercharging. Towards that end, we explore what accumulated observations reveal about the mechanism of electrospray. We introduce the idea of an intermediate region for electrospray ionization (and other ionization methods) to account for the facts that solution charge state distributions (CSDs) do not correlate to those observed by ESI– MS (the latter bear more charge) and that gas phase reactions can reduce, but not increase the extent of charging. This region incorporates properties, e.g., basicities, intermediate between solution and gas phase. Assuming that droplet species polarize within the high electric field leads to equations describing ion emission resembling those from the equilibrium partitioning model. The equations predict many trends successfully, including CSD shifts to higher m/z for concentrated analytes and shifts to lower m/z for sprays employing smaller emitter opening diameters. From this view, a single mechanism can be formulated to explain how reagents that promote analyte charging (“supercharging”) such as m–NBA, sulfolane, and 3–nitrobenzonitrile increase analyte charge from “denaturing” and “native” solvent systems. It is suggested that additives’ Brønsted basicities are inversely correlated to their ability to shift CSDs to lower m/z in positive ESI, as are Brønsted acidities for negative ESI. Because supercharging agents reduce an analyte's solution ionization, excess spray charge is bestowed on evaporating ions carryingfewer opposing charges. Brønsted basicity (or acidity) determines how much ESI charge is lost to the agent (unavailable to evaporating analyte). PMID:25135609

  12. 24 CFR 200.55 - Financing fees and charges.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 24 Housing and Urban Development 2 2010-04-01 2010-04-01 false Financing fees and charges. 200.55 Section 200.55 Housing and Urban Development Regulations Relating to Housing and Urban Development... Financing fees and charges. Fees and charges approved by the Commissioner in excess of the initial service...

  13. Role of protein surface charge in monellin sweetness.

    PubMed

    Xue, Wei-Feng; Szczepankiewicz, Olga; Thulin, Eva; Linse, Sara; Carey, Jannette

    2009-03-01

    A small number of proteins have the unusual property of tasting intensely sweet. Despite many studies aimed at identifying their sweet taste determinants, the molecular basis of protein sweetness is not fully understood. Recent mutational studies of monellin have implicated positively charged residues in sweetness. In the present work, the effect of overall net charge was investigated using the complementary approach of negative charge alterations. Multiple substitutions of Asp/Asn and Glu/Gln residues radically altered the surface charge of single-chain monellin by removing six negative charges or adding four negative charges. Biophysical characterization using circular dichroism, fluorescence, and two-dimensional NMR demonstrates that the native fold of monellin is preserved in the variant proteins under physiological solution conditions although their stability toward chemical denaturation is altered. A human taste test was employed to determine the sweetness detection threshold of the variants. Removal of negative charges preserves monellin sweetness, whereas added negative charge has a large negative impact on sweetness. Meta-analysis of published charge variants of monellin and other sweet proteins reveals a general trend toward increasing sweetness with increasing positive net charge. Structural mapping of monellin variants identifies a hydrophobic surface predicted to face the receptor where introduced positive or negative charge reduces sweetness, and a polar surface where charges modulate long-range electrostatic complementarity.

  14. Investment Dynamics with Natural Expectations.

    PubMed

    Fuster, Andreas; Hebert, Benjamin; Laibson, David

    2010-01-01

    We study an investment model in which agents have the wrong beliefs about the dynamic properties of fundamentals. Specifically, we assume that agents underestimate the rate of mean reversion. The model exhibits the following six properties: (i) Beliefs are excessively optimistic in good times and excessively pessimistic in bad times. (ii) Asset prices are too volatile. (iii) Excess returns are negatively autocorrelated. (iv) High levels of corporate profits predict negative future excess returns. (v) Real economic activity is excessively volatile; the economy experiences amplified investment cycles. (vi) Corporate profits are positively autocorrelated in the short run and negatively autocorrelated in the medium run. The paper provides an illustrative model of animal spirits, amplified business cycles, and excess volatility.

  15. Investment Dynamics with Natural Expectations*

    PubMed Central

    Fuster, Andreas; Hebert, Benjamin; Laibson, David

    2012-01-01

    We study an investment model in which agents have the wrong beliefs about the dynamic properties of fundamentals. Specifically, we assume that agents underestimate the rate of mean reversion. The model exhibits the following six properties: (i) Beliefs are excessively optimistic in good times and excessively pessimistic in bad times. (ii) Asset prices are too volatile. (iii) Excess returns are negatively autocorrelated. (iv) High levels of corporate profits predict negative future excess returns. (v) Real economic activity is excessively volatile; the economy experiences amplified investment cycles. (vi) Corporate profits are positively autocorrelated in the short run and negatively autocorrelated in the medium run. The paper provides an illustrative model of animal spirits, amplified business cycles, and excess volatility. PMID:23243469

  16. The influence of charge and the distribution of charge in the polar region of phospholipids on the activity of UDP-glucuronosyltransferase.

    PubMed

    Zakim, D; Eibl, H

    1992-07-05

    Studies of the mechanism of lipid-induced regulation of the microsomal enzyme UDP-glucuronosyltransferase have been extended by examining the influence of charge within the polar region on the ability of lipids to activate delipidated pure enzyme. The effects of net negative charge, of charge separation in phosphocholine, and of the distribution of charge in the polar region of lipids were studied using the GT2p isoform isolated from pig liver. Prior experiments have shown that lipids with net negative charge inhibit the enzyme (Zakim, D., Cantor, M., and Eibl, H. (1988) J. Biol. Chem. 263, 5164-5169). The current experiments show that the extent of inhibition on a molar basis increases as the net negative charge increases from -1 to -2. The inhibitory effect of negatively charged lipids is on the functional state of the enzyme and is not due to electrostatic repulsion of negatively charged substrates of the enzyme. Although the inhibitory effect of net negative charge is removed when negative charge is balanced by a positive charge due to a quaternary nitrogen, neutrality of the polar region is not a sufficient condition for activation of the enzyme. In addition to a balance of charge between Pi and the quaternary nitrogen, the distance between the negative and positive charges and the orientation of the dipole created by them are critical for activation of GT2p. The negative and positive charges must be separated by the equivalent of three -CH2- groups for optimal activation by a lipid. Shortening this distance by one -CH2- unit leads to a lipid that is ineffective in activating the enzyme. Reversal of the orientation of the dipole in which the negative charge is on the polymethylene side of the lipid-water interface and the positive charge extends into water also produces a lipid that is not effective for activating GT2p. On the other hand, lipids with phosphoserine as the polar region, which has the "normal" P-N distance but carries a net negative charge, do not inhibit GT2p. This result again illustrates the importance of the dipole of phosphocholine for modulating the functional state of GT2p.

  17. Negative Social Evaluation Impairs Executive Functions in Adolescents With Excess Weight: Associations With Autonomic Responses.

    PubMed

    Padilla, María Moreno; Fernández-Serrano, María J; Verdejo García, Antonio; Reyes Del Paso, Gustavo A

    2018-06-22

    Adolescents with excess weight suffer social stress more frequently than their peers with normal weight. To examine the impact of social stress, specifically negative social evaluation, on executive functions in adolescents with excess weight. We also examined associations between subjective stress, autonomic reactivity, and executive functioning. Sixty adolescents (aged 13-18 years) classified into excess weight or normal weight groups participated. We assessed executive functioning (working memory, inhibition, and shifting) and subjective stress levels before and after the Trier Social Stress Task (TSST). The TSST was divided into two phases according to the feedback of the audience: positive and negative social evaluation. Heart rate and skin conductance were recorded. Adolescents with excess weight showed poorer executive functioning after exposure to TSST compared with adolescents with normal weight. Subjective stress and autonomic reactivity were also greater in adolescents with excess weight than adolescents with normal weight. Negative social evaluation was associated with worse executive functioning and increased autonomic reactivity in adolescents with excess weight. The findings suggest that adolescents with excess weight are more sensitive to social stress triggered by negative evaluations. Social stress elicited deterioration of executive functioning in adolescents with excess weight. Evoked increases in subjective stress and autonomic responses predicted decreased executive function. Deficits in executive skills could reduce cognitive control abilities and lead to overeating in adolescents with excess weight. Strategies to cope with social stress to prevent executive deficits could be useful to prevent future obesity in this population.

  18. Dynamics of Charge Carriers in Silicon Nanowire Photoconductors Revealed by Photo Hall Effect Measurements.

    PubMed

    Chen, Kaixiang; Zhao, Xiaolong; Mesli, Abdelmadjid; He, Yongning; Dan, Yaping

    2018-04-24

    Photoconductors have extraordinarily high gain in quantum efficiency, but the origin of the gain has remained in dispute for decades. In this work, we employ photo Hall effect to reveal the gain mechanisms by probing the dynamics of photogenerated charge carriers in silicon nanowire photoconductors. The results reveal that a large number of photogenerated minority electrons are localized in the surface depletion region and surface trap states. The same number of excess hole counterparts is left in the nanowire conduction channel, resulting in the fact that excess holes outnumber the excess electrons in the nanowire conduction channel by orders of magnitude. The accumulation of the excess holes broadens the conduction channel by narrowing down the depletion region, which leads to the experimentally observed high photo gain.

  19. Ending an Insurgency Violently: The Samar and Batangas Punitive Campaigns

    DTIC Science & Technology

    2010-03-01

    outrage over charges of excessive cruelty and war crimes. In contrast, the Batangas campaign plan, under the direction of BG J. Franklin Bell, is... cruelty and war crimes. In contrast, the Batangas campaign plan, under the direction of BG J. Franklin Bell, is remembered as a balanced strategy of...over charges of excessive cruelty and war crimes. Nevertheless, both campaigns provide an opportunity to study the proper balance of attraction and

  20. Ozone and dinitrogen monoxide production in atmospheric pressure air dielectric barrier discharge plasma effluent generated by nanosecond pulse superimposed alternating current voltage

    NASA Astrophysics Data System (ADS)

    Takashima, Keisuke; Kaneko, Toshiro

    2017-06-01

    The effects of nanosecond pulse superposition to alternating current voltage (NS + AC) on the generation of an air dielectric barrier discharge (DBD) plasma and reactive species are experimentally studied, along with measurements of ozone (O3) and dinitrogen monoxide (N2O) in the exhausted gas through the air DBD plasma (air plasma effluent). The charge-voltage cycle measurement indicates that the role of nanosecond pulse superposition is to induce electrical charge transport and excess charge accumulation on the dielectric surface following the nanosecond pulses. The densities of O3 and N2O in NS + AC DBD are found to be significantly increased in the plasma effluent, compared to the sum of those densities generated in NS DBD and AC DBD operated individually. The production of O3 and N2O is modulated significantly by the phase in which the nanosecond pulse is superimposed. The density increase and modulation effects by the nanosecond pulse are found to correspond with the electrical charge transport and the excess electrical charge accumulation induced by the nanosecond pulse. It is suggested that the electrical charge transport by the nanosecond pulse might result in the enhancement of the nanosecond pulse current, which may lead to more efficient molecular dissociation, and the excess electrical charge accumulation induced by the nanosecond pulse increases the discharge coupling power which would enhance molecular dissociation.

  1. Effects of Excess Carriers on Charged Defect Concentrations in Wide Bandgap Semiconductors

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Alberi, Kirstin M; Scarpulla, Michael A.

    Unintentional doping and doping limits in semiconductors are typically caused by compensating defects with low formation energies. Since the formation enthalpy of a charged defect depends linearly on the Fermi level, doping limits can be especially pronounced in wide bandgap semiconductors where the Fermi level can vary substantially. Introduction of non-equilibrium carrier concentrations during growth or processing alters the chemical potentials of band carriers and allows populations of charged defects to be modified in ways impossible at thermal equilibrium. We demonstrate that in the presence of excess carriers, the rates of carrier capture and emission involving a defect charge transitionmore » level determine the admixture of electron and hole quasi-Fermi levels involved in the formation enthalpy of non-zero charge defect states. To understand the range of possible responses, we investigate the behavior of a single donor-like defect as functions of extrinsic doping and charge transition level energy. We find that that excess carriers will increase the formation enthalpy of compensating defects for most values of the charge transition level in the bandgap. Thus, it may be possible to use non-equilibrium carrier concentrations to overcome limitations on doping imposed by native defects. Cases also exist in which the concentration of defects with the same charge polarity as the majority dopant is either left unchanged or actually increases. This surprising effect arises when emission rates are suppressed relative to the capture rates and is most pronounced in wide bandgap semiconductors. We provide guidelines for carrying out experimental tests of this model.« less

  2. Effects of excess carriers on charged defect concentrations in wide bandgap semiconductors

    NASA Astrophysics Data System (ADS)

    Alberi, Kirstin; Scarpulla, Michael A.

    2018-05-01

    Unintentional doping and doping limits in semiconductors are typically caused by compensating defects with low formation energies. Since the formation enthalpy of a charged defect depends linearly on the Fermi level, doping limits can be especially pronounced in wide bandgap semiconductors where the Fermi level can vary substantially. Introduction of non-equilibrium carrier concentrations during growth or processing alters the chemical potentials of band carriers and allows populations of charged defects to be modified in ways impossible at thermal equilibrium. We demonstrate that in the presence of excess carriers, the rates of carrier capture and emission involving a defect charge transition level determine the admixture of electron and hole quasi-Fermi levels involved in the formation enthalpy of non-zero charge defect states. To understand the range of possible responses, we investigate the behavior of a single donor-like defect as functions of extrinsic doping and charge transition level energy. We find that that excess carriers will increase the formation enthalpy of compensating defects for most values of the charge transition level in the bandgap. Thus, it may be possible to use non-equilibrium carrier concentrations to overcome limitations on doping imposed by native defects. Cases also exist in which the concentration of defects with the same charge polarity as the majority dopant is either left unchanged or actually increases. This surprising effect arises when emission rates are suppressed relative to the capture rates and is most pronounced in wide bandgap semiconductors. We provide guidelines for carrying out experimental tests of this model.

  3. 75 FR 47063 - Mutual Fund Distribution Fees; Confirmations

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-08-04

    ... competition for distribution services. The proposed rule and rule amendments are designed to protect... designed to enhance investor understanding of those charges, limit the cumulative sales charges each...(b) was designed to protect funds from being charged excessive sales and promotional expenses.\\26...

  4. CCD imaging sensors

    NASA Technical Reports Server (NTRS)

    Janesick, James R. (Inventor); Elliott, Stythe T. (Inventor)

    1989-01-01

    A method for promoting quantum efficiency (QE) of a CCD imaging sensor for UV, far UV and low energy x-ray wavelengths by overthinning the back side beyond the interface between the substrate and the photosensitive semiconductor material, and flooding the back side with UV prior to using the sensor for imaging. This UV flooding promotes an accumulation layer of positive states in the oxide film over the thinned sensor to greatly increase QE for either frontside or backside illumination. A permanent or semipermanent image (analog information) may be stored in a frontside SiO.sub.2 layer over the photosensitive semiconductor material using implanted ions for a permanent storage and intense photon radiation for a semipermanent storage. To read out this stored information, the gate potential of the CCD is biased more negative than that used for normal imaging, and excess charge current thus produced through the oxide is integrated in the pixel wells for subsequent readout by charge transfer from well to well in the usual manner.

  5. Recovery curves of the surface electric field after lightning discharges occurring between the positive charge pocket and negative charge centre in a thundercloud

    NASA Astrophysics Data System (ADS)

    Pawar, S. D.; Kamra, A. K.

    2002-12-01

    Surface observations of the electric field recovery curves of the lightning discharges occurring between the positive charge pocket and negative main charge centre in an overhead thundercloud are reported. Such recovery curves are observed to have an additional step of very slow field-change observed at an after-discharge value of electric field equal to 5-6 kV m-1. The behavior of recovery curves is explained in terms of the coronae charge and the relative efficiencies of the charge generating processes responsible for growth of positive charge pocket and main negative charge centre in the thundercloud. The charging currents responsible for the growth of charge in positive charge pockets is computed to be 2-4 times larger than that for the growth of the main negative charge. However, the charge destroyed in such a discharge is found to be comparable to that in a discharge between the main charge centres of the thundercloud.

  6. Theory of Tunneling Spectroscopy in a Mn12 Single-Electron Transistor by Density-Functional Theory Methods

    NASA Astrophysics Data System (ADS)

    Michalak, Ł.; Canali, C. M.; Pederson, M. R.; Paulsson, M.; Benza, V. G.

    2010-01-01

    We consider tunneling transport through a Mn12 molecular magnet using spin density functional theory. A tractable methodology for constructing many-body wave functions from Kohn-Sham orbitals allows for the determination of spin-dependent matrix elements for use in transport calculations. The tunneling conductance at finite bias is characterized by peaks representing transitions between spin multiplets, separated by an energy on the order of the magnetic anisotropy. The energy splitting of the spin multiplets and the spatial part of their many-body wave functions, describing the orbital degrees of freedom of the excess charge, strongly affect the electronic transport, and can lead to negative differential conductance.

  7. Theory of tunneling spectroscopy in a Mn12 single-electron transistor by density-functional theory methods.

    PubMed

    Michalak, Ł; Canali, C M; Pederson, M R; Paulsson, M; Benza, V G

    2010-01-08

    We consider tunneling transport through a Mn12 molecular magnet using spin density functional theory. A tractable methodology for constructing many-body wave functions from Kohn-Sham orbitals allows for the determination of spin-dependent matrix elements for use in transport calculations. The tunneling conductance at finite bias is characterized by peaks representing transitions between spin multiplets, separated by an energy on the order of the magnetic anisotropy. The energy splitting of the spin multiplets and the spatial part of their many-body wave functions, describing the orbital degrees of freedom of the excess charge, strongly affect the electronic transport, and can lead to negative differential conductance.

  8. 14 CFR 158.39 - Use of excess PFC revenue.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ...) AIRPORTS PASSENGER FACILITY CHARGES (PFC'S) Application and Approval § 158.39 Use of excess PFC revenue. (a) If the PFC revenue remitted to the public agency, plus interest earned thereon, exceeds the allowable... 14 Aeronautics and Space 3 2014-01-01 2014-01-01 false Use of excess PFC revenue. 158.39 Section...

  9. 14 CFR 158.39 - Use of excess PFC revenue.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ...) AIRPORTS PASSENGER FACILITY CHARGES (PFC'S) Application and Approval § 158.39 Use of excess PFC revenue. (a) If the PFC revenue remitted to the public agency, plus interest earned thereon, exceeds the allowable... 14 Aeronautics and Space 3 2010-01-01 2010-01-01 false Use of excess PFC revenue. 158.39 Section...

  10. 14 CFR 158.39 - Use of excess PFC revenue.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ...) AIRPORTS PASSENGER FACILITY CHARGES (PFC'S) Application and Approval § 158.39 Use of excess PFC revenue. (a) If the PFC revenue remitted to the public agency, plus interest earned thereon, exceeds the allowable... 14 Aeronautics and Space 3 2011-01-01 2011-01-01 false Use of excess PFC revenue. 158.39 Section...

  11. 14 CFR 158.39 - Use of excess PFC revenue.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ...) AIRPORTS PASSENGER FACILITY CHARGES (PFC'S) Application and Approval § 158.39 Use of excess PFC revenue. (a) If the PFC revenue remitted to the public agency, plus interest earned thereon, exceeds the allowable... 14 Aeronautics and Space 3 2013-01-01 2013-01-01 false Use of excess PFC revenue. 158.39 Section...

  12. 14 CFR 158.39 - Use of excess PFC revenue.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ...) AIRPORTS PASSENGER FACILITY CHARGES (PFC'S) Application and Approval § 158.39 Use of excess PFC revenue. (a) If the PFC revenue remitted to the public agency, plus interest earned thereon, exceeds the allowable... 14 Aeronautics and Space 3 2012-01-01 2012-01-01 false Use of excess PFC revenue. 158.39 Section...

  13. 47 CFR 69.4 - Charges to be filed.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) COMMON CARRIER SERVICES (CONTINUED) ACCESS CHARGES... shall include charges for the End User Common Line element, and for line port costs in excess of basic... each of the following elements: (1) [Reserved] (2) Carrier common line, provided that after June 30...

  14. Excess electrons in methanol clusters: Beyond the one-electron picture

    NASA Astrophysics Data System (ADS)

    Pohl, Gábor; Mones, Letif; Turi, László

    2016-10-01

    We performed a series of comparative quantum chemical calculations on various size negatively charged methanol clusters, ("separators=" CH 3 OH ) n - . The clusters are examined in their optimized geometries (n = 2-4), and in geometries taken from mixed quantum-classical molecular dynamics simulations at finite temperature (n = 2-128). These latter structures model potential electron binding sites in methanol clusters and in bulk methanol. In particular, we compute the vertical detachment energy (VDE) of an excess electron from increasing size methanol cluster anions using quantum chemical computations at various levels of theory including a one-electron pseudopotential model, several density functional theory (DFT) based methods, MP2 and coupled-cluster CCSD(T) calculations. The results suggest that at least four methanol molecules are needed to bind an excess electron on a hydrogen bonded methanol chain in a dipole bound state. Larger methanol clusters are able to form stronger interactions with an excess electron. The two simulated excess electron binding motifs in methanol clusters, interior and surface states, correlate well with distinct, experimentally found VDE tendencies with size. Interior states in a solvent cavity are stabilized significantly stronger than electron states on cluster surfaces. Although we find that all the examined quantum chemistry methods more or less overestimate the strength of the experimental excess electron stabilization, MP2, LC-BLYP, and BHandHLYP methods with diffuse basis sets provide a significantly better estimate of the VDE than traditional DFT methods (BLYP, B3LYP, X3LYP, PBE0). A comparison to the better performing many electron methods indicates that the examined one-electron pseudopotential can be reasonably used in simulations for systems of larger size.

  15. Excess electrons in methanol clusters: Beyond the one-electron picture.

    PubMed

    Pohl, Gábor; Mones, Letif; Turi, László

    2016-10-28

    We performed a series of comparative quantum chemical calculations on various size negatively charged methanol clusters, CH 3 OH n - . The clusters are examined in their optimized geometries (n = 2-4), and in geometries taken from mixed quantum-classical molecular dynamics simulations at finite temperature (n = 2-128). These latter structures model potential electron binding sites in methanol clusters and in bulk methanol. In particular, we compute the vertical detachment energy (VDE) of an excess electron from increasing size methanol cluster anions using quantum chemical computations at various levels of theory including a one-electron pseudopotential model, several density functional theory (DFT) based methods, MP2 and coupled-cluster CCSD(T) calculations. The results suggest that at least four methanol molecules are needed to bind an excess electron on a hydrogen bonded methanol chain in a dipole bound state. Larger methanol clusters are able to form stronger interactions with an excess electron. The two simulated excess electron binding motifs in methanol clusters, interior and surface states, correlate well with distinct, experimentally found VDE tendencies with size. Interior states in a solvent cavity are stabilized significantly stronger than electron states on cluster surfaces. Although we find that all the examined quantum chemistry methods more or less overestimate the strength of the experimental excess electron stabilization, MP2, LC-BLYP, and BHandHLYP methods with diffuse basis sets provide a significantly better estimate of the VDE than traditional DFT methods (BLYP, B3LYP, X3LYP, PBE0). A comparison to the better performing many electron methods indicates that the examined one-electron pseudopotential can be reasonably used in simulations for systems of larger size.

  16. Is the negative glow plasma of a direct current glow discharge negatively charged?

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Bogdanov, E. A.; Saifutdinov, A. I.; Demidov, V. I., E-mail: Vladimir.Demidov@mail.wvu.edu

    A classic problem in gas discharge physics is discussed: what is the sign of charge density in the negative glow region of a glow discharge? It is shown that traditional interpretations in text-books on gas discharge physics that states a negative charge of the negative glow plasma are based on analogies with a simple one-dimensional model of discharge. Because the real glow discharges with a positive column are always two-dimensional, the transversal (radial) term in divergence with the electric field can provide a non-monotonic axial profile of charge density in the plasma, while maintaining a positive sign. The numerical calculationmore » of glow discharge is presented, showing a positive space charge in the negative glow under conditions, where a one-dimensional model of the discharge would predict a negative space charge.« less

  17. Thunderstorm Charge Structures Producing Negative Gigantic Jets

    NASA Astrophysics Data System (ADS)

    Boggs, L.; Liu, N.; Riousset, J. A.; Shi, F.; Rassoul, H.

    2016-12-01

    Here we present observational and modeling results that provide insight into thunderstorm charge structures that produce gigantic jet discharges. The observational results include data from four different thunderstorms producing 9 negative gigantic jets from 2010 to 2014. We used radar, very high frequency (VHF) and low frequency (LF) lightning data to analyze the storm characteristics, charge structures, and lightning activity when the gigantic jets emerged from the parent thunderstorms. A detailed investigation of the evolution of one of the charge structures by analyzing the VHF data is also presented. The newly found charge structure obtained from the observations was analyzed with fractal modeling and compared with previous fractal modeling studies [Krehbiel et al., Nat. Geosci., 1, 233-237, 2008; Riousset et al., JGR, 115, A00E10, 2010] of gigantic jet discharges. Our work finds that for normal polarity thunderstorms, gigantic jet charge structures feature a narrow upper positive charge region over a wide middle negative charge region. There also likely exists a `ring' of negative screening charge located around the perimeter of the upper positive charge. This is different from previously thought charge structures of the storms producing gigantic jets, which had a very wide upper positive charge region over a wide middle negative charge region, with a very small negative screening layer covering the cloud top. The newly found charge structure results in leader discharge trees in the fractal simulations that closely match the parent flashes of gigantic jets inside and outside the thundercloud. The previously used charge structures, while vital to the understanding of gigantic jet initiation and the role of charge imbalances inside the cloud, do not produce leader discharge trees that agree with observed gigantic jet discharges.Finally, the newly discovered gigantic jet charge structures are formed near the end of a convective pulse [Meyer et al., JGR, 118, 2013; Lazarus et al., JGR, 120, 8469-8490, 2015] that pushes the negative screening charge radially outward and causes mixing around the updraft.

  18. 7 CFR 91.41 - Charges for demonstrations and courses of instruction.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... MARKETING SERVICE (Standards, Inspections, Marketing Practices), DEPARTMENT OF AGRICULTURE (CONTINUED... demonstrations and courses of instruction. Charges, not in excess of the cost thereof and as approved by the...

  19. Genetics Home Reference: SLC4A1-associated distal renal tubular acidosis

    MedlinePlus

    ... exchanger 1 (AE1) protein, which transports negatively charged atoms (anions) across cell membranes. Specifically, AE1 exchanges negatively charged atoms of chlorine (chloride ions) for negatively charged bicarbonate ...

  20. Excess-Si related defect centers in buried SiO2 thin films

    NASA Astrophysics Data System (ADS)

    Warren, W. L.; Fleetwood, D. M.; Shaneyfelt, M. R.; Schwank, J. R.; Winokur, P. S.; Devine, R. A. B.

    1993-06-01

    Using electron paramagnetic resonance (EPR) and capacitance-voltage measurements we have investigated the role of excess-silicon related defect centers as charge traps in separation by the implantation of oxygen materials. Three types of EPR-active centers were investigated: oxygen vacancy Eγ' centers (O3≡Si• +Si≡O3), delocalized Eδ' centers, and D centers (Si3≡Si•). It was found that all of these paramagnetic centers are created by selective hole injection, and are reasonably ascribed as positively charged when paramagnetic. These results provide the first experimental evidence for (1) the charge state of the Eδ' center, and (2) that the D center is an electrically active point defect in these materials.

  1. NMR detects molecular interactions of graphene with aromatic and aliphatic hydrocarbons in water

    NASA Astrophysics Data System (ADS)

    Bichenkova, Elena V.; Raju, Arun P. A.; Burusco, Kepa K.; Kinloch, Ian A.; Novoselov, Kostya S.; Clarke, David J.

    2018-03-01

    Polyaromatic carbon is widely held to be strongly diamagnetic and hydrophobic, with textbook van der Waals and ‘π-stacked’ binding of hydrocarbons, which disrupt their self-assembled supramolecular structures. The NMR of organic molecules sequestered by polyaromatic carbon is expected to be dominated by shielding from the orbital diamagnetism of π electrons. We report the first evidence of very different polar and magnetic behavior in water, wherein graphene remained well-dispersed after extensive dialysis and behaved as a 1H-NMR-silent ghost. Magnetic effects dominated the NMR of organic structures which interacted with graphene, with changes in spin-spin coupling, vast increase in relaxation, line broadening and decrease in NMR peak heights when bound to graphene. However, the interactions were weak, reversible and did not disrupt organic self-assemblies reliant on hydrophobic ‘π-stacking’, even when substantially sequestered on the surface of graphene by the high surface area available. Interacting assemblies of aromatic molecules retained their strongly-shielded NMR signals and remained within self-assembled structures, with slower rates of diffusion from association with graphene, but with no further shielding from graphene. Binding to graphene was selective for positively-charged organic assemblies, weaker for non-aromatic and negligible for strongly-negatively-charged molecules, presumably repelled by a negative zeta potential of graphene in water. Stronger binders, or considerable excess of weaker binders readily reversed physisorption, with no evidence of structural changes from chemisorption. The fundamental nature of these different electronic interactions between organic and polyaromatic carbon is considered with relevance to electronics, charge storage, sensor, medical, pharmaceutical and environmental research.

  2. Flocculation of Clay Colloids Induced by Model Polyelectrolytes: Effects of Relative Charge Density and Size.

    PubMed

    Sakhawoth, Yasine; Michot, Laurent J; Levitz, Pierre; Malikova, Natalie

    2017-10-06

    Flocculation and its tuning are of utmost importance in the optimization of several industrial protocols in areas such as purification of waste water and civil engineering. Herein, we studied the polyelectrolyte-induced flocculation of clay colloids on a model system consisting of purified clay colloids of well-defined size fractions and ionene polyelectrolytes presenting regular and tunable chain charge density. To characterize ionene-induced clay flocculation, we turned to the combination of light absorbance (turbidity) and ζ-potential measurements, as well as adsorption isotherms. Our model system allowed us to identify the exact ratio of positive and negative charges in clay-ionene mixtures, the (c+/c-) ratio. For all samples studied, the onset of efficient flocculation occurred consistently at c+/c- ratios significantly below 1, which indicated the formation of highly ionene-deficient aggregates. At the same time, the ζ-potential measurements indicated an apparent zero charge on such aggregates. Thus, the ζ-potential values could not provide the stoichiometry inside the clay-ionene aggregates. The early onset of flocculation in clay-ionene mixtures is reminiscent of the behavior of multivalent salts and contrasts that of monovalent salts, for which a large excess amount of ions is necessary to achieve flocculation. Clear differences in the flocculation behavior are visible as a function of the ionene charge density, which governs the conformation of the ionene chains on the clay surface. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  3. Hydrated proton and hydroxide charge transfer at the liquid/vapor interface of water

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Soniat, Marielle; Rick, Steven W., E-mail: srick@uno.edu; Kumar, Revati

    2015-07-28

    The role of the solvated excess proton and hydroxide ions in interfacial properties is an interesting scientific question with applications in a variety of aqueous behaviors. The role that charge transfer (CT) plays in interfacial behavior is also an unsettled question. Quantum calculations are carried out on clusters of water with an excess proton or a missing proton (hydroxide) to determine their CT. The quantum results are applied to analysis of multi-state empirical valence bond trajectories. The polyatomic nature of the solvated excess proton and hydroxide ion results in directionally dependent CT, depending on whether a water molecule is amore » hydrogen bond donor or acceptor in relation to the ion. With polyatomic molecules, CT also depends on the intramolecular bond distances in addition to intermolecular distances. The hydrated proton and hydroxide affect water’s liquid/vapor interface in a manner similar to monatomic ions, in that they induce a hydrogen-bonding imbalance at the surface, which results in charged surface waters. This hydrogen bond imbalance, and thus the charged waters at the surface, persists until the ion is at least 10 Å away from the interface.« less

  4. Exploring the jet multiplicity in the 750 GeV diphoton excess

    DOE PAGES

    Dalchenko, Mykhailo; Dutta, Bhaskar; Gao, Yu; ...

    2016-10-01

    The recent diphoton excess at the LHC has been explained tentatively by a Standard Model (SM) singlet scalar of 750 GeV in mass, in the association of heavy particles with SM gauge charges. These new particles with various SM gauge charges induce loop-level couplings of the new scalar to WW, ZZ, Zγ, γγ, and gg. Here, we show that the strength of the couplings to the gauge bosons also determines the production mechanism of the scalar particle via WW,ZZ,Zγ,γγ,gg fusion which leads to individually distinguishable jet distributions in the final state where the statistics will be improved in the ongoingmore » run. Finally, the number of jets and the leading jet's transverse momentum distribution in the excess region of the diphoton signal can be used to determine the coupling of the scalar to the gauge bosons arising from the protons which subsequently determine the charges of the heavy particles that arise from various well-motivated models.« less

  5. Charge transfer in TATB and HMX under extreme conditions.

    PubMed

    Zhang, Chaoyang; Ma, Yu; Jiang, Daojian

    2012-11-01

    Charge transfer is usually accompanied by structural changes in materials under different conditions. However, the charge transfer in energetic materials that are subjected to extreme conditions has seldom been explored by researchers. In the work described here, the charge transfer in single molecules and unit cells of the explosives TATB and HMX under high temperatures and high pressures was investigated by performing static and dynamic calculations using three DFT methods, including the PWC functional of LDA, and the BLYP and PBE functionals of GGA. The results showed that negative charge is transferred from the nitro groups of molecular or crystalline TATB and HMX when they are heated. All DFT calculations for the compressed TATB unit cell indicate that, generally, negative charge transfer occurs to its nitro groups as the compression increases. PWC and PBE calculations for crystalline HMX show that negative charge is first transferred to the nitro groups but, as the compression increases, the negative charge is transferred from the nitro groups. However, the BLYP calculations indicated that there was gradual negative charge transfer to the nitro groups of HMX, similar to the case for TATB. The unrelaxed state of the uniformly compressed TATB causes negative charge to be transferred from its nitro groups, in contrast to what is seen in the relaxed state. Charge transfer in TATB is predicted to occur much more easily than in HMX.

  6. 12 CFR 404.9 - Schedule of fees.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... attempt to conduct searches in the most efficient manner to minimize costs for both Ex-Im Bank and the... as follows: (1) Commercial use requesters. Ex-Im Bank shall charge the full costs for search, review... shall charge only for the cost of duplication in excess of 100 pages. No fee will be charged for search...

  7. 12 CFR 404.9 - Schedule of fees.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... attempt to conduct searches in the most efficient manner to minimize costs for both Ex-Im Bank and the... as follows: (1) Commercial use requesters. Ex-Im Bank shall charge the full costs for search, review... shall charge only for the cost of duplication in excess of 100 pages. No fee will be charged for search...

  8. 12 CFR 404.9 - Schedule of fees.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... attempt to conduct searches in the most efficient manner to minimize costs for both Ex-Im Bank and the... as follows: (1) Commercial use requesters. Ex-Im Bank shall charge the full costs for search, review... shall charge only for the cost of duplication in excess of 100 pages. No fee will be charged for search...

  9. 12 CFR 404.9 - Schedule of fees.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... attempt to conduct searches in the most efficient manner to minimize costs for both Ex-Im Bank and the... as follows: (1) Commercial use requesters. Ex-Im Bank shall charge the full costs for search, review... shall charge only for the cost of duplication in excess of 100 pages. No fee will be charged for search...

  10. 18 CFR 367.23 - Transactions with non-associate companies.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... excess or deficiency of the cost on servicing the non-associate companies must be charged to account 458... charged to account 458.4 (§ 367.4584). In computing charges to associate companies for any calendar year, any net credit in this account must be deducted from amounts reimbursable by associate companies as...

  11. 32 CFR 766.11 - Fees for landing, parking and storage.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... aircraft will be charged fees if their government charges similar fees for U.S. Government aircraft. (2... (Regular and Reserve) or retired, provided the aircraft is not used for commercial purposes. (7) Landing... landing), a landing fee in excess of the normal landing fee will be charged to cover the additional...

  12. Stress Reactivity in Traditional Chinese Medicine–Based Subgroups of Patients with Irritable Bowel Syndrome

    PubMed Central

    Chang, Megan C.; Shapiro, David; Joshi, Aditi; Shahabi, Leila; Tan, Steven; Smith, Suzanne; Hui, Ka Kit; Tillisch, Kirsten; Mayer, Emeran A.

    2014-01-01

    Abstract Objectives: This study aimed to examine differences in autonomic responses to stress, pain perception, and the role of negative affect in these responses in individuals with irritable bowel syndrome (IBS) according to Traditional Chinese Medicine (TCM) classifications. Design: Fifty-nine female patients with IBS age 18–65 years diagnosed by TCM practitioners as showing primarily an excess (n=32) or an overlap (n=27) pattern (mixed excess and deficiency) were assessed for symptom differences, heart rate, and skin conductance responses to a psychosocial stressor and pain perception. Settings/Locations: University of California in Los Angeles, California. Results: Compared with the excess group, the overlap group showed significantly greater overall gastrointestinal symptom severity, abdominal pain, and negative affect. The excess group with higher levels of negative affect showed greater reactivity to stress, whereas the overlap group showed an opposite response pattern. The overlap group showed increased cold sensitivity. Conclusions: IBS patients with the overlap pattern have greater disease severity and comorbidity than those with excess alone. Those with excess showed a pattern of increased stress response with greater negative affect, whereas the overlap group with greater deficiency showed lower physiologic arousal with greater negative affect, consistent with depletion resulting from allostatic load. PMID:24256027

  13. 38 CFR 36.4212 - Interest rates and late charges.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... any advance, or in the event of any delinquency or default; Provided, that a late charge not in excess... Reserve Board of the Federal Reserve System. The Federal Reserve Statistical Release Report H.15 (519) is...

  14. Impacts of side chain and excess energy on the charge photogeneration dynamics of low-bandgap copolymer-fullerene blends

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Huo, Ming-Ming, E-mail: hithuomm@163.com; Zhang, Jian-Ping, E-mail: jpzhang@chem.ruc.edu.cn, E-mail: hjhzlz@iccas.ac.cn; Department of Chemistry, Renmin University of China, Beijing 100872

    2014-02-28

    Primary charge photogeneration dynamics in neat and fullerene-blended films of a pair of alternating benzo[1,2-b:4,5-b{sup ′}]dithiophene (BDT) and thieno[3,4-b]thiophene (TT) copolymers are comparatively studied by using near-infrared, time-resolved absorption (TA) spectroscopy under low excitation photon fluence. PBDTTT-E and PBDTTT-C, differed merely in the respective TT-substituents of ester (-E) and carbonyl (-C), show distinctly different charge photogeneration dynamics. The pair of neat PBDTTT films show exciton lifetimes of ∼0.1 ns and fluorescence quantum yields below 0.2%, as well as prominent excess-energy enhanced exciton dissociation. In addition, PBDTTT-C gives rise to >50% higher P{sup •+} yield than PBDTTT-E does irrespective to themore » excitation photon energy. Both PBDTTT-E:PC{sub 61}BM and PBDTTT-C:PC{sub 61}BM blends show subpicosecond exciton lifetimes and nearly unitary fluorescence quenching efficiency and, with respect to the former blend, the latter one shows substantially higher branching ratio of charge separated (CS) state over interfacial charge transfer (ICT) state, and hence more efficient exciton-to-CS conversion. For PBDTTT-C:PC{sub 61}BM, the ultrafast charge dynamics clearly show the processes of ICT-CS interconversion and P{sup •+} migration, which are possibly influenced by the ICT excess energy. However, such processes are relatively indistinctive in the case of PBDTTT-E:PC{sub 61}BM. The results strongly prove the importance of ICT dissociation in yielding free charges, and are discussed in terms of the film morphology and the precursory solution-phase macromolecular conformation.« less

  15. Observation and analysis of electrical structure change and diversity in thunderstorms on the Qinghai-Tibet Plateau

    NASA Astrophysics Data System (ADS)

    Li, Yajun; Zhang, Guangshu; Wang, Yanhui; Wu, Bin; Li, Jing

    2017-09-01

    A comprehensive observation on thunderstorms was conducted in the Qinghai area by using a very high frequency three-dimensional lightning mapping system and Doppler radar. The spatio-temporal evolution of the charge structure of the isolated thunderstorm was analyzed according to the developing process of thunderstorm, and the reasons for the change in charge structure diversity were studied. During the initial developing and mature stages of the thunderstorm, the charge structure was a steady negative dipole polarity, i.e., the negative charge region was above the positive charge region. Furthermore, the total number of flashes was lower during these two stages. During the thunderstorm's dissipation stage, the charge structure was varied and complicated, with a positive dipole, negative dipole, and a tripole charge structure changing and coexisting during this stage. This charge structure diversity was primarily caused by the collision and merging of two local thunderstorm cells, leading to a charge rearrangement and distribution and the formation of a new charge structure. The frequency of the negative cloud-to-ground and intracloud flashes increased sharply in the dissipation stage, reaching a maximum value. The increase in frequency of negative cloud-to-ground was mainly caused by the lower positive charge weakening during the dissipation stage. In addition, the relationship between charging regions and temperature layers was analyzed by combining sounding temperature data with the theory of a non-inductive charging mechanism.

  16. Intermetallic negative electrodes for non-aqueous lithium cells and batteries

    DOEpatents

    Thackeray, Michael M.; Vaughey, John T.; Johnson, Christopher S.; Fransson, Linda M.; Edstrom, Ester Kristina; Henriksen, Gary

    2004-05-04

    A method of operating an electrochemical cell is disclosed. The cell has an intermetallic negative electrode of Cu.sub.6-x M.sub.x Sn.sub.5, wherein x is .ltoreq.3 and M is one or more metals including Si and a positive electrode containing Li in which Li is shuttled between the positive electrode and the negative electrode during charge and discharge to form a lithiated intermetallic negative electrode during charge. The voltage of the electrochemical cell is controlled during the charge portion of the charge-discharge cycles so that the potential of the lithiated intermetallic negative electrode in the fully charged electrochemical cell is less than 0.2 V but greater than 0 V versus metallic lithium.

  17. Variation in Emergency Department vs Internal Medicine Excess Charges in the United States.

    PubMed

    Xu, Tim; Park, Angela; Bai, Ge; Joo, Sarah; Hutfless, Susan M; Mehta, Ambar; Anderson, Gerard F; Makary, Martin A

    2017-08-01

    Uninsured and insured but out-of-network emergency department (ED) patients are often billed hospital chargemaster prices, which exceed amounts typically paid by insurers. To examine the variation in excess charges for services provided by emergency medicine and internal medicine physicians. Retrospective analysis was conducted of professional fee payment claims made by the Centers for Medicare & Medicaid Services for all services provided to Medicare Part B fee-for-service beneficiaries in calendar year 2013. Data analysis was conducted from January 1 to July 31, 2016. Markup ratios for ED and internal medicine professional services, defined as the charges submitted by the hospital divided by the Medicare allowable amount. Our analysis included 12 337 emergency medicine physicians from 2707 hospitals and 57 607 internal medicine physicians from 3669 hospitals in all 50 states. Services provided by emergency medicine physicians had an overall markup ratio of 4.4 (340% excess charges), which was greater than the markup ratio of 2.1 (110% excess charges) for all services performed by internal medicine physicians. Markup ratios for all ED services ranged by hospital from 1.0 to 12.6 (median, 4.2; interquartile range [IQR], 3.3-5.8); markup ratios for all internal medicine services ranged by hospital from 1.0 to 14.1 (median, 2.0; IQR, 1.7-2.5). The median markup ratio by hospital for ED evaluation and management procedure codes varied between 4.0 and 5.0. Among the most common ED services, laceration repair had the highest median markup ratio (7.0); emergency medicine physician review of a head computed tomographic scan had the greatest interhospital variation (range, 1.6-27.7). Across hospitals, markups in the ED were often substantially higher than those in the internal medicine department for the same services. Higher ED markup ratios were associated with hospital for-profit ownership (median, 5.7; IQR, 4.0-7.1), a greater percentage of uninsured patients seen (median, 5.0; IQR, 3.5-6.7 for ≥20% uninsured), and location (median, 5.3; IQR, 3.8-6.8 for the southeastern United States). Across hospitals, there is wide variation in excess charges on ED services, which are often priced higher than internal medicine services. Our results inform policy efforts to protect uninsured and out-of-network patients from highly variable pricing.

  18. Polarization spectroscopy of positive and negative trions in an InAs quantum dot

    NASA Astrophysics Data System (ADS)

    Ware, Morgan E.; Bracker, Allan S.; Stinaff, Eric; Gammon, Daniel; Gershoni, David; Korenev, Vladimir L.

    2005-02-01

    Using polarization-sensitive photoluminescence and photoluminescence excitation spectroscopy, we study single InAs/GaAs self-assembled quantum dots. The dots were embedded in an n-type, Schottky diode structure allowing for control of the charge state. We present here the exciton, singly charged exciton (positive and negative trions), and the twice negatively charged exciton. For non-resonant excitation below the wetting layer, we observed a large degree of polarization memory from the radiative recombination of both the positive and negative trions. In excitation spectra, through the p-shell, we have found several sharp resonances in the emission from the s-shell recombination of the dot in all charged states. Some of these excitation resonances exhibit strong coulomb shifts upon addition of charges into the quantum dot. One particular resonance of the negatively charged trion was found to exhibit a fine structure doublet under circular polarization. This observation is explained in terms of resonant absorption into the triplet states of the negative trion.

  19. Hydrated Excess Protons Can Create Their Own Water Wires.

    PubMed

    Peng, Yuxing; Swanson, Jessica M J; Kang, Seung-gu; Zhou, Ruhong; Voth, Gregory A

    2015-07-23

    Grotthuss shuttling of an excess proton charge defect through hydrogen bonded water networks has long been the focus of theoretical and experimental studies. In this work we show that there is a related process in which water molecules move ("shuttle") through a hydrated excess proton charge defect in order to wet the path ahead for subsequent proton charge migration. This process is illustrated through reactive molecular dynamics simulations of proton transport through a hydrophobic nanotube, which penetrates through a hydrophobic region. Surprisingly, before the proton enters the nanotube, it starts "shooting" water molecules into the otherwise dry space via Grotthuss shuttling, effectively creating its own water wire where none existed before. As the proton enters the nanotube (by 2-3 Å), it completes the solvation process, transitioning the nanotube to the fully wet state. By contrast, other monatomic cations (e.g., K(+)) have just the opposite effect, by blocking the wetting process and making the nanotube even drier. As the dry nanotube gradually becomes wet when the proton charge defect enters it, the free energy barrier of proton permeation through the tube via Grotthuss shuttling drops significantly. This finding suggests that an important wetting mechanism may influence proton translocation in biological systems, i.e., one in which protons "create" their own water structures (water "wires") in hydrophobic spaces (e.g., protein pores) before migrating through them. An existing water wire, e.g., one seen in an X-ray crystal structure or MD simulations without an explicit excess proton, is therefore not a requirement for protons to transport through hydrophobic spaces.

  20. Hydrated Excess Protons Can Create Their Own Water Wires

    PubMed Central

    2014-01-01

    Grotthuss shuttling of an excess proton charge defect through hydrogen bonded water networks has long been the focus of theoretical and experimental studies. In this work we show that there is a related process in which water molecules move (“shuttle”) through a hydrated excess proton charge defect in order to wet the path ahead for subsequent proton charge migration. This process is illustrated through reactive molecular dynamics simulations of proton transport through a hydrophobic nanotube, which penetrates through a hydrophobic region. Surprisingly, before the proton enters the nanotube, it starts “shooting” water molecules into the otherwise dry space via Grotthuss shuttling, effectively creating its own water wire where none existed before. As the proton enters the nanotube (by 2–3 Å), it completes the solvation process, transitioning the nanotube to the fully wet state. By contrast, other monatomic cations (e.g., K+) have just the opposite effect, by blocking the wetting process and making the nanotube even drier. As the dry nanotube gradually becomes wet when the proton charge defect enters it, the free energy barrier of proton permeation through the tube via Grotthuss shuttling drops significantly. This finding suggests that an important wetting mechanism may influence proton translocation in biological systems, i.e., one in which protons “create” their own water structures (water “wires”) in hydrophobic spaces (e.g., protein pores) before migrating through them. An existing water wire, e.g., one seen in an X-ray crystal structure or MD simulations without an explicit excess proton, is therefore not a requirement for protons to transport through hydrophobic spaces. PMID:25369445

  1. No need to be HAMLET or BAMLET to interact with histones: binding of monomeric alpha-lactalbumin to histones and basic poly-amino acids.

    PubMed

    Permyakov, Serge E; Pershikova, Irina V; Khokhlova, Tatyana I; Uversky, Vladimir N; Permyakov, Eugene A

    2004-05-18

    The ability of a specific complex of human alpha-lactalbumin with oleic acid (HAMLET) to induce cell death with selectivity for tumor and undifferentiated cells was shown recently to be mediated by interaction of HAMLET with histone proteins irreversibly disrupting chromatin structure [Duringer, C., et al. (2003) J. Biol. Chem. 278, 42131-42135]. Here we show that monomeric alpha-lactalbumin (alpha-LA) in the absence of fatty acids is also able to bind efficiently to the primary target of HAMLET, histone HIII, regardless of Ca(2+) content. Thus, the modification of alpha-LA by oleic acid is not required for binding to histones. We suggest that interaction of negatively charged alpha-LA with the basic histone stabilizes apo-alpha-LA and destabilizes the Ca(2+)-bound protein due to compensation for excess negative charge of alpha-LA's Ca(2+)-binding loop by positively charged residues of the histone. Spectrofluorimetric curves of titration of alpha-LA by histone H3 were well approximated by a scheme of cooperative binding of four alpha-LA molecules per molecule of histone, with an equilibrium dissociation constant of 1.0 microM. Such a stoichiometry of binding implies that the binding process is not site-specific with respect to histone and likely is driven by just electrostatic interactions. Co-incubation of positively charged poly-amino acids (poly-Lys and poly-Arg) with alpha-LA resulted in effects which were similar to those caused by histone HIII, confirming the electrostatic nature of the alpha-LA-histone interaction. In all cases that were studied, the binding was accompanied by aggregation. The data indicate that alpha-lactalbumin can be used as a basis for the design of antitumor agents, acting through disorganization of chromatin structure due to interaction between alpha-LA and histone proteins.

  2. Negative differential mobility for negative carriers as revealed by space charge measurements on crosslinked polyethylene insulated model cables

    NASA Astrophysics Data System (ADS)

    Teyssedre, G.; Vu, T. T. N.; Laurent, C.

    2015-12-01

    Among features observed in polyethylene materials under relatively high field, space charge packets, consisting in a pulse of net charge that remains in the form of a pulse as it crosses the insulation, are repeatedly observed but without complete theory explaining their formation and propagation. Positive charge packets are more often reported, and the models based on negative differential mobility(NDM) for the transport of holes could account for some charge packets phenomenology. Conversely, NDM for electrons transport has never been reported so far. The present contribution reports space charge measurements by pulsed electroacoustic method on miniature cables that are model of HVDC cables. The measurements were realized at room temperature or with a temperature gradient of 10 °C through the insulation under DC fields on the order 30-60 kV/mm. Space charge results reveal systematic occurrence of a negative front of charges generated at the inner electrode that moves toward the outer electrode at the beginning of the polarization step. It is observed that the transit time of the front of negative charge increases, and therefore the mobility decreases, with the applied voltage. Further, the estimated mobility, in the range 10-14-10-13 m2 V-1 s-1 for the present results, increases when the temperature increases for the same condition of applied voltage. The features substantiate the hypothesis of negative differential mobility used for modelling space charge packets.

  3. Method of adhesion between an oxide layer and a metal layer

    DOEpatents

    Jennison, Dwight R.; Bogicevic, Alexander; Kelber, Jeffry A.; Chambers, Scott A.

    2004-09-14

    A method of controlling the wetting characteristics and increasing the adhesion between a metal and an oxide layer. By introducing a negatively-charged species to the surface of an oxide layer, layer-by-layer growth of metal deposited onto the oxide surface is promoted, increasing the adhesion strength of the metal-oxide interface. The negatively-charged species can either be deposited onto the oxide surface or a compound can be deposited that dissociates on, or reacts with, the surface to form the negatively-charged species. The deposited metal adatoms can thereby bond laterally to the negatively-charged species as well as vertically to the oxide surface as well as react with the negatively charged species, be oxidized, and incorporated on or into the surface of the oxide.

  4. Internal Charging

    NASA Technical Reports Server (NTRS)

    Minow, Joseph I.

    2014-01-01

    (1) High energy (>100keV) electrons penetrate spacecraft walls and accumulate in dielectrics or isolated conductors; (2) Threat environment is energetic electrons with sufficient flux to charge circuit boards, cable insulation, and ungrounded metal faster than charge can dissipate; (3) Accumulating charge density generates electric fields in excess of material breakdown strenght resulting in electrostatic discharge; and (4) System impact is material damage, discharge currents inside of spacecraft Faraday cage on or near critical circuitry, and RF noise.

  5. Kinetic mechanism for reversible structural transition in MoTe2 induced by excess charge carriers

    NASA Astrophysics Data System (ADS)

    Rubel, O.

    2018-06-01

    Kinetic of a reversible structural transition between insulating (2H) and metallic (1T ') phases in a monolayer MoTe2 due to an electrostatic doping is studied using first-principle calculations. The driving force for the structural transition is the energy gained by transferring excess electrons from the bottom of the conduction band to lower energy gapless states in the metallic phase as have been noticed in earlier studies. The corresponding structural transformation involves dissociation of Mo-Te bonds (one per formula unit), which results in a kinetic energy barrier of 0.83 eV. The transformation involves a consecutive movement of atoms similar to a domain wall motion. The presence of excess charge carriers modifies not only the total energy of the initial and final states, but also lowers an energy of the transition state. An experimentally observed hysteresis in the switching process can be attributed to changes in the kinetic energy barrier due to its dependence on the excess carrier density.

  6. Retrieval of charge mobility from apparent charge packet movements in LDPE thin films

    NASA Astrophysics Data System (ADS)

    Meng, Jia; Zhang, Yewen; Holé, Stéphane; Zheng, Feihu; An, Zhenlian

    2017-03-01

    The charge packet phenomenon observed in polyethylene materials has been reported extensively during the last decades. To explain its movement, Negative Differential Mobility (NDM) theory is a competitive model among several proposed mechanisms. However, as a key concept of this theory, a sufficiently acute relationship between charge mobility and electric field has never been reported until now, which makes it hard to precisely describe the migration of charge packets with this theory. Based on the substantial negative-charge packet observations with a sufficiently by wide electric field range from 15 kV/mm to 50 kV/mm, the present contribution successfully retrieved the negative-charge mobility from the apparent charge packet movements, which reveals a much closer relationship between the NDM theory and charge packet migrations. Back simulations of charge packets with the retrieved charge mobility offer a good agreement with the experimental data.

  7. Salt Bridge Rearrangement (SaBRe) Explains the Dissociation Behavior of Noncovalent Complexes

    NASA Astrophysics Data System (ADS)

    Loo, Rachel R. Ogorzalek; Loo, Joseph A.

    2016-06-01

    Native electrospray ionization-mass spectrometry, with gas-phase activation and solution compositions that partially release subcomplexes, can elucidate topologies of macromolecular assemblies. That so much complexity can be preserved in gas-phase assemblies is remarkable, although a long-standing conundrum has been the differences between their gas- and solution-phase decompositions. Collision-induced dissociation of multimeric noncovalent complexes typically distributes products asymmetrically (i.e., by ejecting a single subunit bearing a large percentage of the excess charge). That unexpected behavior has been rationalized as one subunit "unfolding" to depart with more charge. We present an alternative explanation based on heterolytic ion-pair scission and rearrangement, a mechanism that inherently partitions charge asymmetrically. Excessive barriers to dissociation are circumvented in this manner, when local charge rearrangements access a lower-barrier surface. An implication of this ion pair consideration is that stability differences between high- and low-charge state ions usually attributed to Coulomb repulsion may, alternatively, be conveyed by attractive forces from ion pairs (salt bridges) stabilizing low-charge state ions. Should the number of ion pairs be roughly inversely related to charge, symmetric dissociations would be favored from highly charged complexes, as observed. Correlations between a gas-phase protein's size and charge reflect the quantity of restraining ion pairs. Collisionally-facilitated salt bridge rearrangement (SaBRe) may explain unusual size "contractions" seen for some activated, low charge state complexes. That some low-charged multimers preferentially cleave covalent bonds or shed small ions to disrupting noncovalent associations is also explained by greater ion pairing in low charge state complexes.

  8. Salt Bridge Rearrangement (SaBRe) Explains the Dissociation Behavior of Noncovalent Complexes.

    PubMed

    Loo, Rachel R Ogorzalek; Loo, Joseph A

    2016-06-01

    Native electrospray ionization-mass spectrometry, with gas-phase activation and solution compositions that partially release subcomplexes, can elucidate topologies of macromolecular assemblies. That so much complexity can be preserved in gas-phase assemblies is remarkable, although a long-standing conundrum has been the differences between their gas- and solution-phase decompositions. Collision-induced dissociation of multimeric noncovalent complexes typically distributes products asymmetrically (i.e., by ejecting a single subunit bearing a large percentage of the excess charge). That unexpected behavior has been rationalized as one subunit "unfolding" to depart with more charge. We present an alternative explanation based on heterolytic ion-pair scission and rearrangement, a mechanism that inherently partitions charge asymmetrically. Excessive barriers to dissociation are circumvented in this manner, when local charge rearrangements access a lower-barrier surface. An implication of this ion pair consideration is that stability differences between high- and low-charge state ions usually attributed to Coulomb repulsion may, alternatively, be conveyed by attractive forces from ion pairs (salt bridges) stabilizing low-charge state ions. Should the number of ion pairs be roughly inversely related to charge, symmetric dissociations would be favored from highly charged complexes, as observed. Correlations between a gas-phase protein's size and charge reflect the quantity of restraining ion pairs. Collisionally-facilitated salt bridge rearrangement (SaBRe) may explain unusual size "contractions" seen for some activated, low charge state complexes. That some low-charged multimers preferentially cleave covalent bonds or shed small ions to disrupting noncovalent associations is also explained by greater ion pairing in low charge state complexes. Graphical Abstract ᅟ.

  9. Electrochemical detection of dopamine using porphyrin-functionalized graphene.

    PubMed

    Wu, Li; Feng, Lingyan; Ren, Jinsong; Qu, Xiaogang

    2012-04-15

    A new type of porphyrin-functionalized graphene was synthesized and used for highly selective and sensitive detection of dopamine (DA). The aromatic π-π stacking and electrostatic attraction between positively-charged dopamine and negatively-charged porphyrin-modified graphene can accelerate the electron transfer whereas weakening ascorbic acid (AA) and uric acid (UA) oxidation on the porphyrin-functionalized graphene-modified electrode. Differential pulse voltammetry was used for electrochemical detection, the separation of the oxidation peak potentials for AA-DA, DA-UA and UA-AA is about 188 mV, 144 mV and 332 mV, which allows selectively determining DA. The detection limit of DA can be as low as 0.01 μM. More importantly, the sensor we presented can detect DA in the presence of large excess of ascorbic acid and uric acid. With good sensitivity and selectivity, the present method was applied to the determination of DA in real hydrochloride injection sample, human urine and serum samples, respectively, and the results was satisfactory. Copyright © 2012 Elsevier B.V. All rights reserved.

  10. Generation and acceleration of neutral atoms in intense laser plasma experiments

    NASA Astrophysics Data System (ADS)

    Tata, Sheroy; Mondal, Angana; Sarkar, Shobhik; Ved, Yash; Lad, Amit D.; Pasley, John; Colgan, James; Krishnamurthy, M.

    2017-10-01

    The interaction of a high intensity (>=1018 W/cm2), high contrast (>=109), ultra-short (30fs) laser with solid targets generates a highly dense hot plasma. The quasi-static electric fields in such plasmas are well known for ion acceleration via the target normal sheath acceleration process. Under such conditions charge reduction to generate fast neutral atoms is almost inhibited. Improvised Thomson parabola spectrometry with improved signal to noise ratio has enabled us to measure the signals of fast neutral atoms and negative ions having energies in excess of tens of keV. A study on the neutralization of accelerated protons in plasma shows that the neutral atom to all particle ratio rises sharply from a few percent at the highest detectable energy to 50 % at 15 keV. Using usual charge transfer reactions the generation of neutral atoms can not be explained, thus we conjecture that the neutralization of the accelerated ions is not from the hot dense region of the plasma but neutral atom formation takes place by co-propagating ions with low energy electrons enhancing the effective neutral ratio.

  11. Optimization of microelectrophoresis to select highly negatively charged sperm.

    PubMed

    Simon, Luke; Murphy, Kristin; Aston, Kenneth I; Emery, Benjamin R; Hotaling, James M; Carrell, Douglas T

    2016-06-01

    The sperm membrane undergoes extensive surface remodeling as it matures in the epididymis. During this process, the sperm is encapsulated in an extensive glycocalyx layer, which provides the membrane with its characteristic negative electrostatic charge. In this study, we develop a method of microelectrophoresis and standardize the protocol to isolate sperm with high negative membrane charge. Under an electric field, the percentage of positively charged sperm (PCS), negatively charged sperm (NCS), and neutrally charged sperm was determined for each ejaculate prior to and following density gradient centrifugation (DGC), and evaluated for sperm DNA damage, and histone retention. Subsequently, PCS, NCS, and neutrally charged sperm were selected using an ICSI needle and directly analyzed for DNA damage. When raw semen was analyzed using microelectrophoresis, 94 % were NCS. In contrast, DGC completely or partially stripped the negative membrane charge from sperm resulting PCS and neutrally charged sperm, while the charged sperm populations are increased with an increase in electrophoretic current. Following DGC, high sperm DNA damage and abnormal histone retention were inversely correlated with percentage NCS and directly correlated with percentage PCS. NCS exhibited significantly lower DNA damage when compared with control (P < 0.05) and PCS (P < 0.05). When the charged sperm population was corrected for neutrally charged sperm, sperm DNA damage was strongly associated with NCS at a lower electrophoretic current. The results suggest that selection of NCS at lower current may be an important biomarker to select healthy sperm for assisted reproductive treatment.

  12. Noise And Charge Transport In Carbon Nanotube Devices

    NASA Astrophysics Data System (ADS)

    Reza, Shahed; Huynh, Quyen T.; Bosman, Gijs; Sippel, Jennifer; Rinzler, Andrew G.

    2005-11-01

    The charge transport and noise properties of three terminal, gated devices containing multiple, single wall, metallic and semiconductor carbon nanotubes have been measured as a function of gate and drain bias at 300K. Using pulsed bias the metallic tubes could be burned sequentially enabling the separation of measured conductance and low frequency excess noise into metallic and semiconductor contributions. The relative low frequency excess noise of the metallic tubes was about a factor 100 lower than that of the semiconductor tubes, whereas the conductance of the metallic tubes was significantly higher (10 to 50 times) than that of the semiconductor tubes.

  13. Charging of dust grains in a plasma with negative ions

    NASA Astrophysics Data System (ADS)

    Kim, Su-Hyun; Merlino, Robert L.

    2006-05-01

    The effect of negative ions on the charging of dust particles in a plasma is investigated experimentally. A plasma containing a very low percentage of electrons is formed in a single-ended SF6 is admitted into the vacuum system. The relatively cold (Te≈0.2eV ) readily attach to SF6 molecules to form SF6- negative ions. Calculations of the dust charge indicate that for electrons, negative ions, and positive ions of comparable temperatures, the charge (or surface potential) of the dust can be positive if the positive ion mass is smaller than the negative ion mass and if ɛ, the ratio of the electron to positive ion density, is sufficiently small. The K+ positive ions (mass 39amu) and SF6- negative ions (mass 146amu), and also utilizes a rotating cylinder to dispense dust into the plasma column. Analysis of the current-voltage characteristics of a Langmuir probe in the dusty plasma shows evidence for the reduction in the (magnitude) of the negative dust charge and the transition to positively charged dust as the relative concentration of the residual electrons is reduced. Some remarks are offered concerning experiments that could become possible in a dusty plasma with positive grains.

  14. 49 CFR 374.401 - Minimum permissible limitations for baggage liability.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...) FEDERAL MOTOR CARRIER SAFETY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION FEDERAL MOTOR CARRIER SAFETY REGULATIONS PASSENGER CARRIER REGULATIONS Notice of and Procedures for Baggage Excess Value Declaration § 374... permit the passenger, for an additional charge, to declare a value in excess of the limited amount, and...

  15. Devices that can identify positive vs. negative charge

    NASA Astrophysics Data System (ADS)

    Lincoln, James

    2017-10-01

    When your clothes come out of the dryer, covered with static, do you know whether they are positively or negatively charged? In this article, I discuss a variety of devices that can determine sign of the charge on an insulator or conductor. Purposefully, none of these methods utilize comparison with a known charge. Some of these ideas have been previously published, and I am extending them, but many are original. These demonstrations provide students and teachers with an opportunity to contrast the actual flow of charge with conventional current and to compare the behavior of positive and negative charges with what we expect from protons and electrons.

  16. Lightning Channels of Cloud-to-Ground Flashes Neutralizing Multiple Charge Regions Inside Winter Thunderclouds

    NASA Astrophysics Data System (ADS)

    Akita, Manabu; Yoshida, Satoru; Nakamura, Yoshitaka; Morimoto, Takeshi; Ushio, Tomoo; Kawasaki, Zen-Ichiro; Wang, Daohong

    Lightning Research Group of Osaka University (LRG-OU) has been developing and improving the VHF broadband digital interferometer (DITF) for thunderstorm observations. It enables us to locate the impulsive VHF radiation sources caused by lightning discharges with extremely high resolutions. As a result of the VHF observations during the 2007-2008 winter season in the Japan Sea coastal area, cloud-to-ground (CG) flashes that neutralize multiple charge regions inside thunderclouds are visualized by the VHF broadband DITF. The first flash is the positive CG flash that neutralizes multiple positive charge regions in a flash. The second flash is the bipolar lightning flash that neutralizes both positive and negative charge inside thunderclouds. In the case of bipolar lightning flashes, some tens millisecond after the return strokes, the subsequent negative breakdowns initiate from the proximities of the initiation points of the preceding negative stepped leaders. It was also found that the altitudes of negative charge regions are lower than 2km. The bipolar lightning flashes observed in this campaign neutralize positive charge after lowering the negative charge to the ground.

  17. 750 GeV diphoton excess at CERN LHC from a dark sector assisted scalar decay

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Bhattacharya, Subhaditya; Patra, Sudhanwa; Sahoo, Nirakar

    2016-06-06

    We present a simple extension of the Standard Model (SM) to explain the recent diphoton excess, reported by CMS and ATLAS at CERN LHC. The SM is extended by a dark sector including a vector-like lepton doublet and a singlet of zero electromagnetic charge, which are odd under a Z{sub 2} symmetry. The charged particle of the vector-like lepton doublet assist the additional scalar, different from SM Higgs, to decay to di-photons of invariant mass around 750 GeV and thus explaining the excess observed at LHC. The admixture of neutral component of the vector-like lepton doublet and singlet constitute themore » dark matter of the Universe. We show the relevant parameter space for correct relic density and direct detection of dark matter.« less

  18. The Charge-Balancing Role of Calcium and Alkali Ions in Per-Alkaline Aluminosilicate Glasses.

    PubMed

    Thomsen, René M; Skibsted, Jørgen; Yue, Yuanzheng

    2018-03-29

    The structural arrangement of alkali-modified calcium aluminosilicate glasses has implications for important properties of these glasses in a wide range of industrial applications. The roles of sodium and potassium and their competition with calcium as network modifiers in peralkaline aluminosilicate glasses have been investigated by 27 Al and 29 Si MAS NMR spectroscopy. The 29 Si MAS NMR spectra are simulated using two models for distributing Al in the silicate glass network. One model assumes a hierarchical, quasi-heterogeneous aluminosilicate network, whereas the other is based on differences in relative lattice energies between Si-O-Si, Al-O-Al, and Si-O-Al linkages. A systematic divergence between these simulations and the experimental 29 Si NMR spectra is observed as a function of the sodium content exceeding that required for stoichiometric charge-balancing of the negatively charged AlO 4 tetrahedra. Similar correlations between simulations and experimental 29 Si NMR spectra cannot be made for the excess calcium content. Moreover, systematic variations in the 27 Al isotropic chemical shifts and the second-order quadrupole effect parameters, derived from the 27 Al MAS NMR spectra, are reported as a function of the SiO 2 content. These observations strongly suggest that alkali ions preferentially charge-balance AlO 4 3- as compared to alkaline earth (calcium) ions. In contrast, calcium dominates over the alkali ions in the formation of nonbridging oxygens associated with the SiO 4 tetrahedra.

  19. Negative differential mobility for negative carriers as revealed by space charge measurements on crosslinked polyethylene insulated model cables

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Teyssedre, G., E-mail: gilbert.teyssedre@laplace.univ-tlse.fr; Laurent, C.; CNRS, LAPLACE, F-31062 Toulouse

    Among features observed in polyethylene materials under relatively high field, space charge packets, consisting in a pulse of net charge that remains in the form of a pulse as it crosses the insulation, are repeatedly observed but without complete theory explaining their formation and propagation. Positive charge packets are more often reported, and the models based on negative differential mobility(NDM) for the transport of holes could account for some charge packets phenomenology. Conversely, NDM for electrons transport has never been reported so far. The present contribution reports space charge measurements by pulsed electroacoustic method on miniature cables that are modelmore » of HVDC cables. The measurements were realized at room temperature or with a temperature gradient of 10 °C through the insulation under DC fields on the order 30–60 kV/mm. Space charge results reveal systematic occurrence of a negative front of charges generated at the inner electrode that moves toward the outer electrode at the beginning of the polarization step. It is observed that the transit time of the front of negative charge increases, and therefore the mobility decreases, with the applied voltage. Further, the estimated mobility, in the range 10{sup −14}–10{sup −13} m{sup 2} V{sup −1} s{sup −1} for the present results, increases when the temperature increases for the same condition of applied voltage. The features substantiate the hypothesis of negative differential mobility used for modelling space charge packets.« less

  20. Charge Management in LISA Pathfinder: The Continuous Discharging Experiment

    NASA Astrophysics Data System (ADS)

    Ewing, Becca Elizabeth

    2018-01-01

    Test mass charging is a significant source of excess force and force noise in LISA Pathfinder (LPF). The planned design scheme for mitigation of charge induced force noise in LISA is a continuous discharge by UV light illumination. We report on analysis of a charge management experiment on-board LPF conducted during December 2016. We discuss the measurement of test mass charging noise with and without continuous UV illumination, in addition to the dynamic response in the continuous discharge scheme. Results of the continuous discharge system will be discussed for their application to operating LISA with lower test mass charge.

  1. Understanding Excessive School Absenteeism as School Refusal Behavior

    ERIC Educational Resources Information Center

    Dube, Shanta R.; Orpinas, Pamela

    2009-01-01

    Understanding excessive absenteeism is important to ameliorating the negative outcomes associated with the behavior. The present study examined behavioral reinforcement profiles of school refusal behavior: negative reinforcement (avoidance) and positive reinforcement (gaining parental attention or receiving tangible benefits from not attending…

  2. 47 CFR 32.1170 - Receivables.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... process of collection. (b) Collections in excess of amounts charged to this account may be credited to and carried in this account until applied against charges for services rendered or until refunded. (c) Cost of... Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) COMMON CARRIER SERVICES UNIFORM SYSTEM OF ACCOUNTS...

  3. A high ratio of IC31® adjuvant to antigen is necessary for H4 TB vaccine immunomodulation

    PubMed Central

    Aboutorabian, Sepideh; Hakimi, Jalil; Boudet, Florence; Montano, Sandrine; Dookie, Annie; Roque, Cristopher; Ausar, Salvador F; Rahman, Nausheen; Brookes, Roger H

    2015-01-01

    A tuberculosis (TB) vaccine consisting of a recombinant fusion protein (H4) and a novel TLR9 adjuvant (IC31) is in clinical development. To better understand the H4-IC31 ratio, we measured the binding capacity of IC31 for H4 protein and immunized mice with formulations that contained limiting to excess ratios of IC31 to H4. An immunomodulated H4-specific IFNγ response was only observed when IC31 was present in excess of H4. Since TLR expression is species-specific and the vaccine is intended to boost BCG-primed immunity, we questioned whether data in mice would translate to humans. To address this question, we used the fresh human Whole Blood (hWB) recovered from BCG-vaccinated subjects to screen H4-IC31 formulations. We found IC31 modulation in hWB to be quite distinct from the TLR4-Adjuvant. Unlike TLR4-Adjuvant, IC31 formulations did not induce the pro-inflammatory cytokine TNFα, but modulated a robust H4-specific IFNγ response after 12 d of culture. We then re-stimulated the fresh hWB of 5 BCG-primed subjects with formulations that had excess or limiting IC31 binding for H4 protein and again found that an immunomodulated H4-specific IFNγ response needed an excess of IC31. Finally, we monitored the zeta (ζ) potential of H4-IC31 formulations and found that the overall charge of H4-IC31 particles changes from negative to positive once IC31 is in greater than 9-fold excess. Using two diverse yet mutually supportive approaches, we confirm the need for an excess of IC31 adjuvant in H4 TB vaccine formulations and suggest surface potential may be an important factor. PMID:25997147

  4. A high ratio of IC31(®) adjuvant to antigen is necessary for H4 TB vaccine immunomodulation.

    PubMed

    Aboutorabian, Sepideh; Hakimi, Jalil; Boudet, Florence; Montano, Sandrine; Dookie, Annie; Roque, Cristopher; Ausar, Salvador F; Rahman, Nausheen; Brookes, Roger H

    2015-01-01

    A tuberculosis (TB) vaccine consisting of a recombinant fusion protein (H4) and a novel TLR9 adjuvant (IC31) is in clinical development. To better understand the H4-IC31 ratio, we measured the binding capacity of IC31 for H4 protein and immunized mice with formulations that contained limiting to excess ratios of IC31 to H4. An immunomodulated H4-specific IFNγ response was only observed when IC31 was present in excess of H4. Since TLR expression is species-specific and the vaccine is intended to boost BCG-primed immunity, we questioned whether data in mice would translate to humans. To address this question, we used the fresh human Whole Blood (hWB) recovered from BCG-vaccinated subjects to screen H4-IC31 formulations. We found IC31 modulation in hWB to be quite distinct from the TLR4-Adjuvant. Unlike TLR4-Adjuvant, IC31 formulations did not induce the pro-inflammatory cytokine TNFα, but modulated a robust H4-specific IFNγ response after 12 d of culture. We then re-stimulated the fresh hWB of 5 BCG-primed subjects with formulations that had excess or limiting IC31 binding for H4 protein and again found that an immunomodulated H4-specific IFNγ response needed an excess of IC31. Finally, we monitored the zeta (ζ) potential of H4-IC31 formulations and found that the overall charge of H4-IC31 particles changes from negative to positive once IC31 is in greater than 9-fold excess. Using two diverse yet mutually supportive approaches, we confirm the need for an excess of IC31 adjuvant in H4 TB vaccine formulations and suggest surface potential may be an important factor.

  5. Immune complexes with cationic antibodies deposit in glomeruli more effectively than cationic antibodies alone.

    PubMed

    Mannik, M; Gauthier, V J; Stapleton, S A; Agodoa, L Y

    1987-06-15

    In previously published studies, highly cationized antibodies alone and in immune complexes bound to glomeruli by charge-charge interaction, but only immune complexes persisted in glomeruli. Because normal IgG does not deposit in glomeruli, studies were conducted to determine whether cationized antibodies can be prepared which deposit in glomeruli when bound to antigen but not when free in circulation. A series of cationized rabbit antiHSA was prepared with the number of added amino groups ranging from 13.3 to 60.2 per antibody molecule. Antibodies alone or in preformed soluble immune complexes, prepared at fivefold or 50-fold antigen excess, were administered to mice. With the injection of a fixed dose of 100 micrograms per mouse, antibodies alone did not deposit in glomeruli with less than 29.6 added amino groups by immunofluorescence microscopy. In contrast, 100 micrograms of antibodies with 23.5 added amino groups in immune complexes, made at fivefold antigen excess, formed immune deposits in glomeruli. With selected preparations of cationized, radiolabeled antibodies, deposition in glomeruli was quantified by isolation of mouse glomeruli. These quantitative data were in good agreement with the results of immunofluorescence microscopy. Immune complexes made at 50-fold antigen excess, containing only small-latticed immune complexes with no more than two antibody molecules per complex, deposited in glomeruli similar to antibodies alone. Selected cationized antibodies alone or in immune complexes were administered to mice in varying doses. In these experiments, glomerular deposition of immune complexes, made at fivefold antigen excess, was detected with five- to 10-fold smaller doses than the deposition of the same antibodies alone. These studies demonstrate that antibody molecules in immune complexes are more likely to deposit in glomeruli by charge-charge interactions than antibodies alone.

  6. Bactericidal action mechanism of negatively charged food grade clove oil nanoemulsions.

    PubMed

    Majeed, Hamid; Liu, Fei; Hategekimana, Joseph; Sharif, Hafiz Rizwan; Qi, Jing; Ali, Barkat; Bian, Yuan-Yuan; Ma, Jianguo; Yokoyama, Wallace; Zhong, Fang

    2016-04-15

    Clove oil (CO) anionic nanoemulsions were prepared with varying ratios of CO to canola oil (CA), emulsified and stabilized with purity gum ultra (PGU), a newly developed succinylated waxy maize starch. Interfacial tension measurements showed that CO acted as a co-surfactant and there was a gradual decrease in interfacial tension which favored the formation of small droplet sizes on homogenization until a critical limit (5:5% v/v CO:CA) was reached. Antimicrobial activity of the negatively charged CO nanoemulsion was determined against Gram positive GPB (Listeria monocytogenes and Staphylococcus aureus) and Gram negative GNB (Escherichia coli) bacterial strains using minimum inhibitory concentration (MIC) and a time kill dynamic method. Negatively charged PGU emulsified CO nanoemulsion showed prolonged antibacterial activities against Gram positive bacterial strains. We concluded that negatively charged CO nanoemulsion droplets self-assemble with GPB cell membrane, and facilitated interaction with cellular components of bacteria. Moreover, no electrostatic interaction existed between negatively charged droplets and the GPB membrane. Copyright © 2015 Elsevier Ltd. All rights reserved.

  7. Biochemical Study of Anti-Inflammatory Proteins vCCI and vMIP-II

    DTIC Science & Technology

    2014-07-17

    protein ), where we showed that vCCI is able to bind so many different chemokines due to its general negatively charged surface , allowing it to bind...sample of these competition curves. Our conclusion from the data in Table 1 and Figure 1 is that the negatively charged surface of vCCI allows it to...Similar to our mutagenesis results, the overall data indicate that vCCI uses a negatively charged surface to bind positive charges on the chemokine

  8. Variation in Emergency Department vs Internal Medicine Excess Charges in the United States

    PubMed Central

    Park, Angela; Bai, Ge; Joo, Sarah; Hutfless, Susan M.; Mehta, Ambar; Anderson, Gerard F.; Makary, Martin A.

    2017-01-01

    Importance Uninsured and insured but out-of-network emergency department (ED) patients are often billed hospital chargemaster prices, which exceed amounts typically paid by insurers. Objective To examine the variation in excess charges for services provided by emergency medicine and internal medicine physicians. Design, Setting, and Participants Retrospective analysis was conducted of professional fee payment claims made by the Centers for Medicare & Medicaid Services for all services provided to Medicare Part B fee-for-service beneficiaries in calendar year 2013. Data analysis was conducted from January 1 to July 31, 2016. Main Outcomes and Measures Markup ratios for ED and internal medicine professional services, defined as the charges submitted by the hospital divided by the Medicare allowable amount. Results Our analysis included 12 337 emergency medicine physicians from 2707 hospitals and 57 607 internal medicine physicians from 3669 hospitals in all 50 states. Services provided by emergency medicine physicians had an overall markup ratio of 4.4 (340% excess charges), which was greater than the markup ratio of 2.1 (110% excess charges) for all services performed by internal medicine physicians. Markup ratios for all ED services ranged by hospital from 1.0 to 12.6 (median, 4.2; interquartile range [IQR], 3.3-5.8); markup ratios for all internal medicine services ranged by hospital from 1.0 to 14.1 (median, 2.0; IQR, 1.7-2.5). The median markup ratio by hospital for ED evaluation and management procedure codes varied between 4.0 and 5.0. Among the most common ED services, laceration repair had the highest median markup ratio (7.0); emergency medicine physician review of a head computed tomographic scan had the greatest interhospital variation (range, 1.6-27.7). Across hospitals, markups in the ED were often substantially higher than those in the internal medicine department for the same services. Higher ED markup ratios were associated with hospital for-profit ownership (median, 5.7; IQR, 4.0-7.1), a greater percentage of uninsured patients seen (median, 5.0; IQR, 3.5-6.7 for ≥20% uninsured), and location (median, 5.3; IQR, 3.8-6.8 for the southeastern United States). Conclusions and Relevance Across hospitals, there is wide variation in excess charges on ED services, which are often priced higher than internal medicine services. Our results inform policy efforts to protect uninsured and out-of-network patients from highly variable pricing. PMID:28558093

  9. Excess Volumes and Excess Isentropic Compressibilities of Binary Liquid Mixtures of Trichloroethylene with Esters at 303.15 K

    NASA Astrophysics Data System (ADS)

    Ramanaiah, S.; Rao, C. Narasimha; Nagaraja, P.; Venkateswarlu, P.

    2015-11-01

    Exces volumes, VE, and excess isentropic compressibilities, κSE, have been reported as a function of composition for binary liquid mixtures of trichloroethylene with ethyl acetate, n-propyl acetate, and n-butyl acetate at 303.15 K. Isentropic compressibilities are calculated using measured sound speeds and density data for pure components and for binary mixtures. Excess volumes and excess isentropic compressibilities are found to be negative for the three systems studied over the entire composition range at 303.15 K, whereas these values become more negative with an increase of carbon chain length. The results are discussed in terms of intermolecular interactions between unlike molecules.

  10. Poisson-Boltzmann theory of the charge-induced adsorption of semi-flexible polyelectrolytes.

    PubMed

    Ubbink, Job; Khokhlov, Alexei R

    2004-03-15

    A model is suggested for the structure of an adsorbed layer of a highly charged semi-flexible polyelectrolyte on a weakly charged surface of opposite charge sign. The adsorbed phase is thin, owing to the effective reversal of the charge sign of the surface upon adsorption, and ordered, owing to the high surface density of polyelectrolyte strands caused by the generally strong binding between polyelectrolyte and surface. The Poisson-Boltzmann equation for the electrostatic interaction between the array of adsorbed polyelectrolytes and the charged surface is solved for a cylindrical geometry, both numerically, using a finite element method, and analytically within the weak curvature limit under the assumption of excess monovalent salt. For small separations, repulsive surface polarization and counterion osmotic pressure effects dominate over the electrostatic attraction and the resulting electrostatic interaction curve shows a minimum at nonzero separations on the Angstrom scale. The equilibrium density of the adsorbed phase is obtained by minimizing the total free energy under the condition of equality of chemical potential and osmotic pressure of the polyelectrolyte in solution and in the adsorbed phase. For a wide range of ionic conditions and charge densities of the charged surface, the interstrand separation as predicted by the Poisson-Boltzmann model and the analytical theory closely agree. For low to moderate charge densities of the adsorbing surface, the interstrand spacing decreases as a function of the charge density of the charged surface. Above about 0.1 M excess monovalent salt, it is only weakly dependent on the ionic strength. At high charge densities of the adsorbing surface, the interstrand spacing increases with increasing ionic strength, in line with the experiments by Fang and Yang [J. Phys. Chem. B 101, 441 (1997)]. (c) 2004 American Institute of Physics.

  11. Host-guest chemistry of dendrimer-drug complexes. 2. Effects of molecular properties of guests and surface functionalities of dendrimers.

    PubMed

    Hu, Jingjing; Cheng, Yiyun; Wu, Qinglin; Zhao, Libo; Xu, Tongwen

    2009-08-06

    The host-guest chemistry of dendrimer-drug complexes is investigated by NMR techniques, including (1)H NMR and 2D-NOESY studies. The effects of molecular properties of drug molecules (protonation ability and spatial steric hindrance of charged groups) and surface functionalities of dendrimers (positively charged amine groups and negatively charged carboxylate groups) on the host-guest interactions are discussed. Different interaction mechanisms between dendrimers and drug molecules are proposed on the basis of NMR results. Primary amine- and secondary amine-containing drugs preferentially bind to negatively charged dendrimers by strong electrostatic interactions, whereas tertiary amine and quaternary ammonium-containing drugs have weak binding ability with dendrimers due to relatively low protonation ability of the tertiary amine group and serious steric hindrance of the quaternary ammonium group. Positively charged drugs locate only on the surface of negatively charged dendrimers, whereas negatively charged drugs locate both on the surface and in the interior cavities of positively charged dendrimers. The host-guest chemistry of dendrimer-drug complexes is promising for the development of new drug delivery systems.

  12. Nanotribological Properties of Positively and Negatively charged nanodiamonds as additives to solutions

    NASA Astrophysics Data System (ADS)

    Liu, Zijian; Corley, Steven; Shenderova, Olga; Brenner, Donald; Krim, Jacqueline

    2013-03-01

    Nano-diamond (ND) particles are known to be beneficial for wear and friction reduction when used as additives in liquids, but the fundamental origins of the improvement in tribological properties has not been established. In order to explore this issue, we have investigated the nanotribological properties of ND coated with self-assembled monolayers (SAM) as additives to solutions, employing gold/chrome coated quartz crystal microbalances (QCM). Measurements were performed with the QCM initially immersed in deionized water. ND particles with positively and negatively charged SAM end groups were then added to the water, while the frequency and amplitude of the QCM were monitored. Negative shifts in both the QCM frequency and amplitude were observed when ND with positively charged SAM end groups were added, while positive shifts in both the QCM frequency and amplitude were observed when ND with negatively charged ND end groups were added. The results are consistent with a lubricating effect for the negatively charged ND, but were only observed for sufficiently small negative ND particle size. Experiments on QCM surfaces with differing textures and roughness are in progress, to determine the separate contributing effects of surface roughness charge-water interactions. Funding provided by NSF DMR.

  13. Release of Native-like Gaseous Proteins from Electrospray Droplets via the Charged Residue Mechanism: Insights from Molecular Dynamics Simulations.

    PubMed

    McAllister, Robert G; Metwally, Haidy; Sun, Yu; Konermann, Lars

    2015-10-07

    The mechanism whereby gaseous protein ions are released from charged solvent droplets during electrospray ionization (ESI) remains a matter of debate. Also, it is unclear to what extent electrosprayed proteins retain their solution structure. Molecular dynamics (MD) simulations offer insights into the temporal evolution of protein systems. Surprisingly, there have been no all-atom simulations of the protein ESI process to date. The current work closes this gap by investigating the behavior of protein-containing aqueous nanodroplets that carry excess positive charge. We focus on "native ESI", where proteins initially adopt their biologically active solution structures. ESI proceeds while the protein remains entrapped within the droplet. Protein release into the gas phase occurs upon solvent evaporation to dryness. Droplet shrinkage is accompanied by ejection of charge carriers (Na(+) for the conditions chosen here), keeping the droplet at ∼85% of the Rayleigh limit throughout its life cycle. Any remaining charge carriers bind to the protein as the final solvent molecules evaporate. The outcome of these events is largely independent of the initial protein charge and the mode of charge carrier binding. ESI charge states and collision cross sections of the MD structures agree with experimental data. Our results confirm the Rayleigh/charged residue model (CRM). Field emission of excess Na(+) plays an ancillary role by governing the net charge of the shrinking droplet. Models that envision protein ejection from the droplet are not supported. Most nascent CRM ions retain native-like conformations. For unfolded proteins ESI likely proceeds along routes that are different from the native state mechanism explored here.

  14. Physical activity and exercise dependence during inpatient treatment of longstanding eating disorders: an exploratory study of excessive and non-excessive exercisers.

    PubMed

    Bratland-Sanda, Solfrid; Sundgot-Borgen, Jorunn; Rø, Øyvind; Rosenvinge, Jan H; Hoffart, Asle; Martinsen, Egil W

    2010-04-01

    To describe changes in physical activity (PA) and exercise dependence score during treatment of eating disorders (ED), and to explore correlations among changes in PA, exercise motivation, exercise dependence score and ED psychopathology in excessive and non-excessive exercisers. Thirty-eight adult females receiving inpatient treatment for anorexia nervosa, bulimia nervosa or ED not otherwise specified participated in this prospective study. Assessments included accelerometer assessed PA, Exercise Dependence Scale, Reasons for Exercise Inventory, ED Examination, and ED Inventory. Amount of PA was significantly reduced in non-excessive exercisers during treatment, in excessive exercisers there was a trend towards reduced amount of PA from admission to discharge. In excessive exercisers, reduced ED psychopathology was correlated with reduction in exercise dependence score and perceived importance of exercise to regulate negative affects, but not with importance of exercise for weight/appearance. These associations were not found in non-excessive exercisers. Excessive exercise is an important issue in longstanding ED, and the excessive exercising patients need help to develop alternative strategies to regulate negative affects.

  15. Anisotropy and chemical composition of ultra-high energy cosmic rays using arrival directions measured by the Pierre Auger Observatory

    NASA Astrophysics Data System (ADS)

    Pierre Auger Collaboration; Abreu, P.; Aglietta, M.; Ahn, E. J.; Albuquerque, I. F. M.; Allard, D.; Allekotte, I.; Allen, J.; Allison, P.; Alvarez Castillo, J.; Alvarez-Muñiz, J.; Ambrosio, M.; Aminaei, A.; Anchordoqui, L.; Andringa, S.; Antičić, T.; Anzalone, A.; Aramo, C.; Arganda, E.; Arqueros, F.; Asorey, H.; Assis, P.; Aublin, J.; Ave, M.; Avenier, M.; Avila, G.; Bäcker, T.; Balzer, M.; Barber, K. B.; Barbosa, A. F.; Bardenet, R.; Barroso, S. L. C.; Baughman, B.; Bäuml, J.; Beatty, J. J.; Becker, B. R.; Becker, K. H.; Bellétoile, A.; Bellido, J. A.; BenZvi, S.; Berat, C.; Bertou, X.; Biermann, P. L.; Billoir, P.; Blanco, F.; Blanco, M.; Bleve, C.; Blümer, H.; Boháčová, M.; Boncioli, D.; Bonifazi, C.; Bonino, R.; Borodai, N.; Brack, J.; Brogueira, P.; Brown, W. C.; Bruijn, R.; Buchholz, P.; Bueno, A.; Burton, R. E.; Caballero-Mora, K. S.; Caramete, L.; Caruso, R.; Castellina, A.; Catalano, O.; Cataldi, G.; Cazon, L.; Cester, R.; Chauvin, J.; Cheng, S. H.; Chiavassa, A.; Chinellato, J. A.; Chou, A.; Chudoba, J.; Clay, R. W.; Coluccia, M. R.; Conceição, R.; Contreras, F.; Cook, H.; Cooper, M. J.; Coppens, J.; Cordier, A.; Cotti, U.; Coutu, S.; Covault, C. E.; Creusot, A.; Criss, A.; Cronin, J.; Curutiu, A.; Dagoret-Campagne, S.; Dallier, R.; Dasso, S.; Daumiller, K.; Dawson, B. R.; de Almeida, R. M.; De Domenico, M.; De Donato, C.; de Jong, S. J.; De La Vega, G.; de Mello Junior, W. J. M.; de Mello Neto, J. R. T.; De Mitri, I.; de Souza, V.; de Vries, K. D.; Decerprit, G.; del Peral, L.; Deligny, O.; Dembinski, H.; Dhital, N.; Di Giulio, C.; Diaz, J. C.; Díaz Castro, M. L.; Diep, P. N.; Dobrigkeit, C.; Docters, W.; D'Olivo, J. C.; Dong, P. N.; Dorofeev, A.; dos Anjos, J. C.; Dova, M. T.; D'Urso, D.; Dutan, I.; Ebr, J.; Engel, R.; Erdmann, M.; Escobar, C. O.; Etchegoyen, A.; Facal San Luis, P.; Fajardo Tapia, I.; Falcke, H.; Farrar, G.; Fauth, A. C.; Fazzini, N.; Ferguson, A. P.; Ferrero, A.; Fick, B.; Filevich, A.; Filipčič, A.; Fliescher, S.; Fracchiolla, C. E.; Fraenkel, E. D.; Fröhlich, U.; Fuchs, B.; Gaior, R.; Gamarra, R. F.; Gambetta, S.; García, B.; García Gámez, D.; Garcia-Pinto, D.; Gascon, A.; Gemmeke, H.; Gesterling, K.; Ghia, P. L.; Giaccari, U.; Giller, M.; Glass, H.; Gold, M. S.; Golup, G.; Gomez Albarracin, F.; Gómez Berisso, M.; Gonçalves, P.; Gonzalez, D.; Gonzalez, J. G.; Gookin, B.; Góra, D.; Gorgi, A.; Gouffon, P.; Gozzini, S. R.; Grashorn, E.; Grebe, S.; Griffith, N.; Grigat, M.; Grillo, A. F.; Guardincerri, Y.; Guarino, F.; Guedes, G. P.; Guzman, A.; Hague, J. D.; Hansen, P.; Harari, D.; Harmsma, S.; Harton, J. L.; Haungs, A.; Hebbeker, T.; Heck, D.; Herve, A. E.; Hojvat, C.; Hollon, N.; Holmes, V. C.; Homola, P.; Hörandel, J. R.; Horneffer, A.; Hrabovský, M.; Huege, T.; Insolia, A.; Ionita, F.; Italiano, A.; Jarne, C.; Jiraskova, S.; Kadija, K.; Kampert, K. H.; Karhan, P.; Kasper, P.; Kégl, B.; Keilhauer, B.; Keivani, A.; Kelley, J. L.; Kemp, E.; Kieckhafer, R. M.; Klages, H. O.; Kleifges, M.; Kleinfeller, J.; Knapp, J.; Koang, D.-H.; Kotera, K.; Krohm, N.; Krömer, O.; Kruppke-Hansen, D.; Kuehn, F.; Kuempel, D.; Kulbartz, J. K.; Kunka, N.; La Rosa, G.; Lachaud, C.; Lautridou, P.; Leão, M. S. A. B.; Lebrun, D.; Lebrun, P.; Leigui de Oliveira, M. A.; Lemiere, A.; Letessier-Selvon, A.; Lhenry-Yvon, I.; Link, K.; López, R.; Lopez Aüera, A.; Louedec, K.; Lozano Bahilo, J.; Lucero, A.; Ludwig, M.; Lyberis, H.; Maccarone, M. C.; Macolino, C.; Maldera, S.; Mandat, D.; Mantsch, P.; Mariazzi, A. G.; Marin, J.; Marin, V.; Maris, I. C.; Marquez Falcon, H. R.; Marsella, G.; Martello, D.; Martin, L.; Martinez, H.; Martínez Bravo, O.; Mathes, H. J.; Matthews, J.; Matthews, J. A. J.; Matthiae, G.; Maurizio, D.; Mazur, P. O.; Medina-Tanco, G.; Melissas, M.; Melo, D.; Menichetti, E.; Menshikov, A.; Mertsch, P.; Meurer, C.; Mićanović, S.; Micheletti, M. I.; Miller, W.; Miramonti, L.; Mollerach, S.; Monasor, M.; Monnier Ragaigne, D.; Montanet, F.; Morales, B.; Morello, C.; Moreno, E.; Moreno, J. C.; Morris, C.; Mostafá, M.; Moura, C. A.; Mueller, S.; Muller, M. A.; Müller, G.; Münchmeyer, M.; Mussa, R.; Navarra, G.; Navarro, J. L.; Navas, S.; Necesal, P.; Nellen, L.; Nelles, A.; Nhung, P. T.; Niemietz, L.; Nierstenhoefer, N.; Nitz, D.; Nosek, D.; Nožka, L.; Nyklicek, M.; Oehlschläger, J.; Olinto, A.; Oliva, P.; Olmos-Gilbaja, V. M.; Ortiz, M.; Pacheco, N.; Pakk Selmi-Dei, D.; Palatka, M.; Pallotta, J.; Palmieri, N.; Parente, G.; Parizot, E.; Parra, A.; Parsons, R. D.; Pastor, S.; Paul, T.; Pech, M.; Pȩkala, J.; Pelayo, R.; Pepe, I. M.; Perrone, L.; Pesce, R.; Petermann, E.; Petrera, S.; Petrinca, P.; Petrolini, A.; Petrov, Y.; Petrovic, J.; Pfendner, C.; Phan, N.; Piegaia, R.; Pierog, T.; Pieroni, P.; Pimenta, M.; Pirronello, V.; Platino, M.; Ponce, V. H.; Pontz, M.; Privitera, P.; Prouza, M.; Quel, E. J.; Querchfeld, S.; Rautenberg, J.; Ravel, O.; Ravignani, D.; Revenu, B.; Ridky, J.; Riggi, S.; Risse, M.; Ristori, P.; Rivera, H.; Rizi, V.; Roberts, J.; Robledo, C.; Rodrigues de Carvalho, W.; Rodriguez, G.; Rodriguez Martino, J.; Rodriguez Rojo, J.; Rodriguez-Cabo, I.; Rodríguez-Frías, M. D.; Ros, G.; Rosado, J.; Rossler, T.; Roth, M.; Rouillé-d'Orfeuil, B.; Roulet, E.; Rovero, A. C.; Rühle, C.; Salamida, F.; Salazar, H.; Salina, G.; Sánchez, F.; Santander, M.; Santo, C. E.; Santos, E.; Santos, E. M.; Sarazin, F.; Sarkar, B.; Sarkar, S.; Sato, R.; Scharf, N.; Scherini, V.; Schieler, H.; Schiffer, P.; Schmidt, A.; Schmidt, F.; Schmidt, T.; Scholten, O.; Schoorlemmer, H.; Schovancova, J.; Schovánek, P.; Schöder, F.; Schulte, S.; Schuster, D.; Sciutto, S. J.; Scuderi, M.; Segreto, A.; Settimo, M.; Shadkam, A.; Shellard, R. C.; Sidelnik, I.; Sigl, G.; Silva Lopez, H. H.; Śmiałkowski, A.; Šmída, R.; Snow, G. R.; Sommers, P.; Sorokin, J.; Spinka, H.; Squartini, R.; Stapleton, J.; Stasielak, J.; Stephan, M.; Strazzeri, E.; Stutz, A.; Suarez, F.; Suomijärvi, T.; Supanitsky, A. D.; Šuša, T.; Sutherland, M. S.; Swain, J.; Szadkowski, Z.; Szuba, M.; Tamashiro, A.; Tapia, A.; Tartare, M.; Taşcąu, O.; Tavera Ruiz, C. G.; Tcaciuc, R.; Tegolo, D.; Thao, N. T.; Thomas, D.; Tiffenberg, J.; Timmermans, C.; Tiwari, D. K.; Tkaczyk, W.; Todero Peixoto, C. J.; Tomé, B.; Tonachini, A.; Travnicek, P.; Tridapalli, D. B.; Tristram, G.; Trovato, E.; Tueros, M.; Ulrich, R.; Unger, M.; Urban, M.; Valdés Galicia, J. F.; Valiño, I.; Valore, L.; van den Berg, A. M.; Varela, E.; Vargas Cáardenas, B.; Vázquez, J. R.; Vázquez, R. A.; Veberič, D.; Verzi, V.; Vicha, J.; Videla, M.; Villaseñor, L.; Wahlberg, H.; Wahrlich, P.; Wainberg, O.; Warner, D.; Watson, A. A.; Weber, M.; Weidenhaupt, K.; Weindl, A.; Westerhoff, S.; Whelan, B. J.; Wieczorek, G.; Wiencke, L.; Wilczyńska, B.; Wilczyński, H.; Will, M.; Williams, C.; Winchen, T.; Winders, L.; Winnick, M. G.; Wommer, M.; Wundheiler, B.; Yamamoto, T.; Yapici, T.; Younk, P.; Yuan, G.; Yushkov, A.; Zamorano, B.; Zas, E.; Zavrtanik, D.; Zavrtanik, M.; Zaw, I.; Zepeda, A.; Ziolkowski, M.

    2011-06-01

    The Pierre Auger Collaboration has reported evidence for anisotropy in the distribution of arrival directions of the cosmic rays with energies E > Eth = 5.5 × 1019 eV. These show a correlation with the distribution of nearby extragalactic objects, including an apparent excess around the direction of Centaurus A. If the particles responsible for these excesses at E > Eth are heavy nuclei with charge Z, the proton component of the sources should lead to excesses in the same regions at energies E/Z. We here report the lack of anisotropies in these directions at energies above Eth/Z (for illustrative values of Z = 6,13,26). If the anisotropies above Eth are due to nuclei with charge Z, and under reasonable assumptions about the acceleration process, these observations imply stringent constraints on the allowed proton fraction at the lower energies.

  16. DOE Office of Scientific and Technical Information (OSTI.GOV)

    Pérez-del-Rey, Daniel; Forgács, Dávid; Hutter, Eline M.

    The addition of Sr2+ in CH3NH3PbI3 perovskite films enhances the charge carrier collection efficiency of solar cells leading to very high fill factors, up to 85%. The charge carrier lifetime of Sr2+-containing perovskites is in excess of 40 us, longer than those reported for perovskite single crystals.

  17. 2 CFR 200.430 - Compensation-personal services.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... as specified for teaching activity in paragraph (h)(5)(ii) of this section, charges for work... at a rate not in excess of the IBS. (ii) Charges for teaching activities performed by faculty members... policy of the IHE governing compensation to faculty members for teaching assignments during such periods...

  18. Aberration of a negative ion beam caused by space charge effect.

    PubMed

    Miyamoto, K; Wada, S; Hatayama, A

    2010-02-01

    Aberrations are inevitable when the charged particle beams are extracted, accelerated, transmitted, and focused with electrostatic and magnetic fields. In this study, we investigate the aberration of a negative ion accelerator for a neutral beam injector theoretically, especially the spherical aberration caused by the negative ion beam expansion due to the space charge effect. The negative ion current density profiles with the spherical aberration are compared with those without the spherical aberration. It is found that the negative ion current density profiles in a log scale are tailed due to the spherical aberration.

  19. Dynamics of an excess hole in the 1-methyl-1-butyl-pyrrolidinium dicyanamide ionic-liquid

    NASA Astrophysics Data System (ADS)

    Wu, Fei; Xu, Changhui; Margulis, Claudio J.

    2018-05-01

    In a set of recent publications [C. J. Margulis et al., J. Am. Chem. Soc. 133, 20186 (2011); C. H. Xu et al., J. Am. Chem. Soc. 135, 17528 (2013); C. H. Xu and C. J. Margulis, J. Phys. Chem. B 119, 532 (2015); and K. B. Dhungana et al., J. Phys. Chem. B 121, 8809 (2017)], we explored for selected ionic liquids the early stages of excess charge localization and reactivity relevant both to electrochemical and radiation chemistry processes. In particular, Xu and Margulis [J. Phys. Chem. B 119, 532 (2015)] explored the dynamics of an excess electron in 1-methyl-1-butyl-pyrrolidinium dicyanamide. When electrons are produced from an ionic liquid, the more elusive hole species are also generated. Depending on the nature of cations and anions and the relative alignment of their electronic states in the condensed phase, the very early hole species can nominally be neutral radicals—if the electron is generated from anions—or doubly charged radical cations if their origin is from cations. However, in reality early excess charge localization is more complex and often involves more than one ion. The dynamics and the transient spectroscopy of the hole are the main objects of this study. We find that in the case of 1-methyl-1-butyl-pyrrolidinium dicyanamide, it is the anions that can most easily lose an electron becoming radical species, and that hole localization is mostly on anionic nitrogen. We also find that the driving force for localization of an excess hole appears to be smaller than that for an excess electron in 1-methyl-1-butyl-pyrrolidinium dicyanamide. The early transient hole species can absorb light in the visible, ultraviolet, and near infrared regions, and we are able to identify the type of states being connected by these transitions.

  20. Excess amino acid polymorphism in mitochondrial DNA: contrasts among genes from Drosophila, mice, and humans.

    PubMed

    Rand, D M; Kann, L M

    1996-07-01

    Recent studies of mitochondrial DNA (mtDNA) variation in mammals and Drosophila have shown an excess of amino acid variation within species (replacement polymorphism) relative to the number of silent and replacement differences fixed between species. To examine further this pattern of nonneutral mtDNA evolution, we present sequence data for the ND3 and ND5 genes from 59 lines of Drosophila melanogaster and 29 lines of D. simulans. Of interest are the frequency spectra of silent and replacement polymorphisms, and potential variation among genes and taxa in the departures from neutral expectations. The Drosophila ND3 and ND5 data show no significant excess of replacement polymorphism using the McDonald-Kreitman test. These data are in contrast to significant departures from neutrality for the ND3 gene in mammals and other genes in Drosophila mtDNA (cytochrome b and ATPase 6). Pooled across genes, however, both Drosophila and human mtDNA show very significant excesses of amino acid polymorphism. Silent polymorphisms at ND5 show a significantly higher variance in frequency than replacement polymorphisms, and the latter show a significant skew toward low frequencies (Tajima's D = -1.954). These patterns are interpreted in light of the nearly neutral theory where mildly deleterious amino acid haplotypes are observed as ephemeral variants within species but do not contribute to divergence. The patterns of polymorphism and divergence at charge-altering amino acid sites are presented for the Drosophila ND5 gene to examine the evolution of functionally distinct mutations. Excess charge-altering polymorphism is observed at the carboxyl terminal and excess charge-altering divergence is detected at the amino terminal. While the mildly deleterious model fits as a net effect in the evolution of nonrecombining mitochondrial genomes, these data suggest that opposing evolutionary pressures may act on different regions of mitochondrial genes and genomes.

  1. Recombination energy for negatively charged excitons inside type-II core/shell spherical quantum dots

    NASA Astrophysics Data System (ADS)

    Chafai, A.; Essaoudi, I.; Ainane, A.; Dujardin, F.; Ahuja, R.

    2018-07-01

    The recombination energy of isolated neutral exciton and that of isolated negatively charged exciton inside a type-II core/shell spherical quantum dot are studied. Our investigation considers the charge-carriers effective mass discontinuity at the surface contact between the core and shell materials. Although our model omits the effect of the surface polarization, the dielectric-constant mismatch at the nanodot boundaries was taken into account. In order to achieve the exciton and negative trion energies, we proceed by a variational calculation in the framework of the envelope approximation. Our results reveal a strong correlation between the nanodot morphology and the energy spectrum of the neutral and negatively charged exciton.

  2. Effect of nosocomial vancomycin-resistant enterococcal bacteremia on mortality, length of stay, and costs.

    PubMed

    Song, Xiaoyan; Srinivasan, Arjun; Plaut, David; Perl, Trish M

    2003-04-01

    To determine the impact of vancomycin-resistant enterococcal bacteremia on patient outcomes and costs by assessing mortality, excess length of stay, and charges attributable to it. A population-based, matched, historical cohort study. A 1,025-bed, university-based teaching facility and referral hospital. Two hundred seventy-seven vancomycin-resistant enterococcal bacteremia case-patients and 277 matched control-patients identified between 1993 and 2000. The crude mortality rate was 50.2% and 19.9% for case-patients and control-patients, respectively, yielding a mortality rate of 30.3% attributable to vancomycin-resistant enterococcal bacteremia. The excess length of hospital stay attributable to vancomycin-resistant enterococcal bacteremia was 17 days, of which 12 days were spent in intensive care units. On average, dollars 77,558 in extra charges was attributable to each vancomycin-resistant enterococcal bacteremia. To adjust for severity of illness, 159 pairs of case-patients and control-patients, who had the same severity of illness (All Patient Refined-Diagnosis Related Group complexity level), were further analyzed. When patients were stratified by severity of illness, the crude mortality rate was 50.3% among case-patients compared with 27.7% among control-patients, accounting for an attributable mortality rate of 22.6%. Attributable excess length of stay and charges were 17 days and dollars 81,208, respectively. Vancomycin-resistant enterococcal bacteremia contributes significantly to excess mortality and economic loss, once severity of illness is considered. Efforts to prevent these infections will likely be cost-effective.

  3. Controlling Two-dimensional Tethered Vesicle Motion Using an Electric Field

    PubMed Central

    Yoshina-Ishii, Chiaki; Boxer, Steven G.

    2008-01-01

    We recently introduced methods to tether phospholipid vesicles or proteoliposomes onto a fluid supported lipid bilayer using DNA hybridization. These intact tethered vesicles diffuse in two dimensions parallel to the supporting membrane surface. In this paper, we report the dynamic response of individual tethered vesicles to an electric field applied parallel to the bilayer surface. Vesicles respond to the field by moving in the direction of electro-osmotic flow, and this can be used to reversibly concentrate tethered vesicles against a barrier. By adding increasing amounts of negatively charged phosphatidylserine to the supporting bilayer to increase electro-osmosis, the electrophoretic mobility of the tethered vesicles can be increased. The electro-osmotic contribution can be modeled well by a sphere connected to a cylindrical anchor in a viscous membrane with charged head groups. The electrophoretic force on the negatively charged tethered vesicles opposes the electro-osmotic force. By increasing the amount of negative charge on the tethered vesicle, drift in the direction of electro-osmotic flow can be slowed; at high negative charge on the tethered vesicle, motion can be forced in the direction of electrophoresis. The balance between these forces can be visualized on a patterned supporting bilayer containing negatively charged lipids which themselves reorganize in an externally applied electric field to create a gradient of charge within a corralled region. The charge gradient at the surface creates a gradient of electro-osmotic flow, and vesicles carrying similar amounts of negative charge can be focused to a region perpendicular to the applied field where electrophoresis is balanced by electro-osmosis, away from the corral boundary. Electric fields are effective tools to direct tethered vesicles, concentrate them and to measure the tethered vesicle’s electrostatic properties. PMID:16489833

  4. Gas-Phase Stability of Negatively Charged Organophosphate Metabolites Produced by Electrospray Ionization and Matrix-Assisted Laser Desorption/Ionization

    NASA Astrophysics Data System (ADS)

    Asakawa, Daiki; Mizuno, Hajime; Toyo'oka, Toshimasa

    2017-12-01

    The formation mechanisms of singly and multiply charged organophosphate metabolites by electrospray ionization (ESI) and their gas phase stabilities were investigated. Metabolites containing multiple phosphate groups, such as adenosine 5'-diphosphate (ADP), adenosine 5'-triphosphate (ATP), and D- myo-inositol-1,4,5-triphosphate (IP3) were observed as doubly deprotonated ions by negative-ion ESI mass spectrometry. Organophosphates with multiple negative charges were found to be unstable and often underwent loss of PO3 -, although singly deprotonated analytes were stable. The presence of fragments due to the loss of PO3 - in the negative-ion ESI mass spectra could result in the misinterpretation of analytical results. In contrast to ESI, matrix-assisted laser desorption ionization (MALDI) produced singly charged organophosphate metabolites with no associated fragmentation, since the singly charged anions are stable. The stability of an organophosphate metabolite in the gas phase strongly depends on its charge state. The fragmentations of multiply charged organophosphates were also investigated in detail through density functional theory calculations. [Figure not available: see fulltext.

  5. Charge mobility retrieval approach from apparent charge packet movements based on the negative differential resistance theory.

    PubMed

    Meng, Jia; Zhang, Yewen; Holé, Stéphane; Zheng, Feihu; An, Zhenlian

    2018-04-12

    Space charge migration characteristics play an important role in the evaluation of polymer insulation performance. However, an accurate description of charge carrier mobility in several typical insulating polymers such as polyethylene, polypropylene is currently not available. Recently, with the observation of a series of negative charge packet movements associated with the negative differential resistance characteristic of charge mobility in LDPE films, the extraction of charge mobility from the apparent charge packet movement has been attempted using appropriate methods. Based on the previous report of the successful derivation of charge mobility from experimental results using numerical methods, the present research improves the derivation accuracy and describes the details of the charge mobility derivation procedure. Back simulation results under several typical polarizing fields using the derived charge mobility are exhibited. The results indicate that both the NDR theory and the simulation models for the polyethylene materials are reasonable. A significant migration velocity difference between the charge carrier and the charge packet is observed. Back simulations of the charge packet under several typical polarizing fields using the obtained E-v curve show good agreement with the experimental results. The charge packet shapes during the migrations were also found to vary with the polarizing field.

  6. ESI-MS of Cucurbituril Complexes Under Negative Polarity.

    PubMed

    Rodrigues, Maria A A; Mendes, Débora C; Ramamurthy, Vaidhyanathan; Da Silva, José P

    2017-11-01

    Electrospray ionization mass spectrometry (ESI-MS) is a powerful tool to study host-guest supramolecular interactions. ESI-MS can be used for detailed gas-phase reactivity studies, to clarify the structure, or simply to verify the formation of complexes. Depending on the structure of the host and of the guest, negative and/or positive ESI are used. Here we report the unexpected formation of host-guest complexes between cucurbit[n]urils (n = 7, 8, CB[n]) and amine, styryl pyridine, and styryl pyridine dimer cations, under negative ESI. Non-complexed CB[n] form double charged halide (Br - , Cl - , F - ) adducts. Under negative ESI, halide ions interact with CB[n] outer surface hydrogen atoms. One to one host-guest complexes (1:1) of CB[n] with positive charged guests were also observed as single and double charged ions under negative ESI. The positive charge of guests is neutralized by ion-pairing with halide anions. Depending on the number of positive charges guests retain in the gas phase, one or two additional halide ions are required for neutralization. Complexes 1:2 of CB[8] with styryl pyridines retain two halide ions in the gas phase, one per guest. Styryl pyridine dimers form 1:1 complexes possessing a single extra halide ion and therefore a single positive charge. Negative ESI is sensitive to small structural differences between complexes, distinguishing between 1:2 complexes of styryl pyridine-CB[8] and corresponding 1:1 complexes with the dimer. Negative ESI gives simpler spectra than positive ESI and allows the determination of guest charge state of CB[n] complexes in the gas phase. Graphical Abstract ᅟ.

  7. Oblique Interaction of Dust-ion Acoustic Solitons with Superthermal Electrons in a Magnetized Plasma

    NASA Astrophysics Data System (ADS)

    Parveen, Shahida; Mahmood, Shahzad; Adnan, Muhammad; Qamar, Anisa

    2018-01-01

    The oblique interaction between two dust-ion acoustic (DIA) solitons travelling in the opposite direction, in a collisionless magnetized plasma composed of dynamic ions, static dust (positive/negative) charged particles and interialess kappa distributed electrons is investigated. By employing extended Poincaré-Lighthill-Kuo (PLK) method, Korteweg-de Vries (KdV) equations are derived for the right and left moving low amplitude DIA solitons. Their trajectories and corresponding phase shifts before and after their interaction are also obtained. It is found that in negatively charged dusty plasma above the critical dust charged to ion density ratio the positive polarity pulse is formed, while below the critical dust charged density ratio the negative polarity pulse of DIA soliton exist. However it is found that only positive polarity pulse of DIA solitons exist for the positively charged dust particles case in a magnetized nonthermal plasma. The nonlinearity coefficient in the KdV equation vanishes for the negatively charged dusty plasma case for a particular set of parameters. Therefore, at critical plasma density composition for negatively charged dust particles case, the modified Korteweg-de Vries (mKdV) equations having cubic nonlinearity coefficient of the DIA solitons, and their corresponding phase shifts are derived for the left and right moving solitons. The effects of the system parameters including the obliqueness of solitons propagation with respect to magnetic field direction, superthermality of electrons and concentration of positively/negatively static dust charged particles on the phase shifts of the colliding solitons are also discussed and presented numerically. The results are applicable to space magnetized dusty plasma regimes.

  8. Body weight and health-related quality of life in Catalonia, Spain.

    PubMed

    Oliva-Moreno, Juan; Gil-Lacruz, Ana

    2013-02-01

    Obesity poses important burdens not only on the individuals whose quality of life is reduced but on national welfare systems that have to face growing premature mortality rates, increase healthcare expenditures to treat obesity-related diseases, and earmark vast amounts of healthcare resources for prevention. The main goal of this paper is to analyze the relationship between excess body weight and different dimensions of health-related quality of life for people 16 years and older and to identify the health dimensions most affected by excess weight. We have drawn data from the Catalonia Health Survey (2006). Our results reveal a relationship between excess weight and health-related quality of life. Even after controlling for socio-economic status and objective health variables, excess weight is shown to have a significant negative effect on health-related quality of life. Subjects responses revealed that the negative effect of excess weight was felt the strongest in the health-related quality of life dimensions of mobility and pain/discomfort. Our results indicate there are important differences among gender and age groups. Women and older people are more likely to suffer from the negative consequences of excess weight.

  9. Adhesion of osteoblasts to a nanorough titanium implant surface

    PubMed Central

    Gongadze, Ekaterina; Kabaso, Doron; Bauer, Sebastian; Slivnik, Tomaž; Schmuki, Patrik; van Rienen, Ursula; Iglič, Aleš

    2011-01-01

    This work considers the adhesion of cells to a nanorough titanium implant surface with sharp edges. The basic assumption was that the attraction between the negatively charged titanium surface and a negatively charged osteoblast is mediated by charged proteins with a distinctive quadrupolar internal charge distribution. Similarly, cation-mediated attraction between fibronectin molecules and the titanium surface is expected to be more efficient for a high surface charge density, resulting in facilitated integrin mediated osteoblast adhesion. We suggest that osteoblasts are most strongly bound along the sharp convex edges or spikes of nanorough titanium surfaces where the magnitude of the negative surface charge density is the highest. It is therefore plausible that nanorough regions of titanium surfaces with sharp edges and spikes promote the adhesion of osteoblasts. PMID:21931478

  10. Heavy ion beam-ionosphere interactions - Charging and neutralizing the payload

    NASA Technical Reports Server (NTRS)

    Kaufmann, R. L.; Arnoldy, R. L.; Walker, D. N.; Holmes, J. C.; Pollock, C. J.

    1989-01-01

    Three different electrical charging and neutralization processes were experienced during gun operation in the Argon Release Controlled Studies rocket flights, which carried ion generators to 400-500 km in the nighttime auroral ionosphere: DC charging of the vehicle, brief charging at gun turn-on, and extended oscillatory sequences. The present analysis of these phenomena has determined that, during oscillatory events, the entire environment of a payload could alternate between hot electron and cold electron configurations at rates which may have been in excess of 10 kHz.

  11. 77 FR 26588 - Self-Regulatory Organizations; NASDAQ OMX BX, Inc.; Notice of Filing and Immediate Effectiveness...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-05-04

    ... they deem fee levels at a particular venue to be excessive. In such an environment, BX must continually... excessive extent, it will lose customers to its competitors. Accordingly, BX believes that competitive market forces help to ensure that the fees it charges for execution and routing are reasonable, equitably...

  12. 49 CFR 23.55 - How do recipients count ACDBE participation toward goals for items other than car rentals?

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... its own forces toward ACDBE goals. (e) Count the entire amount of fees or commissions charged by an... reasonable and not excessive as compared with fees customarily allowed for similar services. Such services... that this amount is reasonable and not excessive as compared with fees customarily allowed for similar...

  13. 49 CFR 23.55 - How do recipients count ACDBE participation toward goals for items other than car rentals?

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... its own forces toward ACDBE goals. (e) Count the entire amount of fees or commissions charged by an... reasonable and not excessive as compared with fees customarily allowed for similar services. Such services... that this amount is reasonable and not excessive as compared with fees customarily allowed for similar...

  14. 49 CFR 23.55 - How do recipients count ACDBE participation toward goals for items other than car rentals?

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... its own forces toward ACDBE goals. (e) Count the entire amount of fees or commissions charged by an... reasonable and not excessive as compared with fees customarily allowed for similar services. Such services... that this amount is reasonable and not excessive as compared with fees customarily allowed for similar...

  15. 49 CFR 23.55 - How do recipients count ACDBE participation toward goals for items other than car rentals?

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... its own forces toward ACDBE goals. (e) Count the entire amount of fees or commissions charged by an... reasonable and not excessive as compared with fees customarily allowed for similar services. Such services... that this amount is reasonable and not excessive as compared with fees customarily allowed for similar...

  16. 49 CFR 23.55 - How do recipients count ACDBE participation toward goals for items other than car rentals?

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... its own forces toward ACDBE goals. (e) Count the entire amount of fees or commissions charged by an... reasonable and not excessive as compared with fees customarily allowed for similar services. Such services... that this amount is reasonable and not excessive as compared with fees customarily allowed for similar...

  17. AlInAsSb separate absorption, charge, and multiplication avalanche photodiodes

    NASA Astrophysics Data System (ADS)

    Ren, Min; Maddox, Scott J.; Woodson, Madison E.; Chen, Yaojia; Bank, Seth R.; Campbell, Joe C.

    2016-05-01

    We report AlxIn1-xAsySb1-y separate absorption, charge, and multiplication avalanche photodiodes (APDs) that operate in the short-wavelength infrared spectrum. They exhibit excess noise factor less or equal to that of Si and the low dark currents typical of III-V compound APDs.

  18. 42 CFR 413.130 - Introduction to capital-related costs.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... exists, the deferred charge may be included in capital-related costs to the extent of increasing the... exists, the deferred charge may be included in the capital-related costs to the extent of increasing the... included in capital-related costs to the extent of increasing the reduced rental to an amount not in excess...

  19. Pulsed field sample neutralization

    DOEpatents

    Appelhans, Anthony D.; Dahl, David A.; Delmore, James E.

    1990-01-01

    An apparatus and method for alternating voltage and for varying the rate of extraction during the extraction of secondary particles, resulting in periods when either positive ions, or negative ions and electrons are extracted at varying rates. Using voltage with alternating charge during successive periods to extract particles from materials which accumulate charge opposite that being extracted causes accumulation of surface charge of opposite sign. Charge accumulation can then be adjusted to a ratio which maintains a balance of positive and negative charge emission, thus maintaining the charge neutrality of the sample.

  20. Mobile charge, soft breakdown, and self-healing in hydrogen silsesquioxane based intermetal dielectric

    NASA Astrophysics Data System (ADS)

    Devine, R. A. B.

    2002-09-01

    The electrical characteristics of hydrogen silsesquioxane based flowable oxide (FOxregistered) films proposed for interconnect isolation applications have been studied. It is demonstrated that negative and positive charges exist in the as-made, cured films with densities of 0.95 x1012 and 1.5 x1012 cm-2, respectively for thicknesses of 114 nm. The negative charges can be removed from the films by application of modest electric fields (positive or negative, approx1.75 MV cm-1). The positive charge can be similarly displaced but not removed from the film; this results in time dependent relaxation and redistribution of the positive charge if the films are left unbiased. Time dependent irreversible evolution of the leakage current under positive and negative bias (approx3 MV cm-1) shows a slow breakdown phenomena. An unusual self-healing effect is evidenced in these films.

  1. The Role of Hydrophobicity in the Cellular Uptake of Negatively Charged Macromolecules.

    PubMed

    Abou Matar, Tamara; Karam, Pierre

    2018-02-01

    It is generally accepted that positively charged molecules are the gold standard to by-pass the negatively charged cell membrane. Here, it is shown that cellular uptake is also possible for polymers with negatively charged side chains and hydrophobic backbones. Specifically, poly[5-methoxy-2-(3-sulfopropoxy)-1,4-phenylenevinylene], a conjugated polyelectrolyte with sulfonate, as water-soluble functional groups, is shown to accumulate in the intracellular region. When the polymer hydrophobic backbone is dissolved using polyvinylpyrrolidone, an amphiphilic macromolecule, the cellular uptake is dramatically reduced. The report sheds light on the fine balance between negatively charged side groups and the hydrophobicity of polymers to either enhance or reduce cellular uptake. As a result, these findings will have important ramifications on the future design of targeted cellular delivery nanocarriers for imaging and therapeutic applications. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  2. Stabilized thallium bromide radiation detectors and methods of making the same

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Leao, Cedric Rocha; Lordi, Vincenzo

    According to one embodiment, a crystal includes thallium bromide (TlBr), one or more positively charged dopants, and one or more negatively charged dopants. According to another embodiment, a system includes a monolithic crystal including thallium bromide (TlBr), one or more positively charged dopants, and one or more negatively charged dopants; and a detector configured to detect a signal response of the crystal.

  3. Influence of liposome charge on the association of liposomes with Kupffer cells in vitro. Effects of divalent cations and competition with latex particles.

    PubMed

    Dijkstra, J; van Galen, M; Scherphof, G

    1985-03-14

    We studied the interaction of large unilamellar liposomes carrying different surface charges with rat Kupffer cells in maintenance culture. In addition to 14C-labeled phosphatidylcholine, all liposome preparations contained either 3H-labeled inulin or 125I-labeled bovine serum albumin as a non-degradable or a degradable aqueous space marker, respectively. With vesicles carrying no net charge, intracellular processing of internalized liposomes caused nearly complete release of protein label into the medium in acid-soluble form, while phospholipid label was predominantly retained by the cells, only about one third being released. The presence of the lysosomotropic agent, ammonia, inhibited the release of both labels from the cells. At 4 degrees C, the association and degradation of the vesicles were strongly reduced. These results are very similar to what we reported on negatively charged liposomes (Dijkstra, J., Van Galen, W.J.M., Hulstaert, C.E., Kalicharan, D., Roerdink, F.H. and Scherphof, G.L. (1984) Exp. Cell Res. 150, 161-176). The interaction of both types of vesicles apparently proceeds by adsorption to the cell surface followed by virtually complete internalization by endocytosis. Similar experiments with positively charged vesicles indicated that only about half of the liposomes were taken up by the endocytic route, the other half remaining adsorbed to the cell-surface. Attachment of all types of liposomes to the cells was strongly dependent on the presence of divalent cations; Ca2+ appeared to be required for optimal binding. Neutral liposomes only slightly competed with the uptake of negatively charged vesicles, both at 4 degrees and 37 degrees C, whereas negatively charged small unilamellar vesicles and negatively charged latex beads were found to compete very effectively with the large negatively charged liposomes. Neutral vesicles competed effectively for uptake with positively charged ones. These results suggest that neutral and positively charged liposomes are largely bound by the same cell-surface binding sites, while negatively charged vesicles attach mainly to other binding sites.

  4. Experimental investigation of the excess charge and time constant of minority carriers in the thin diffused layer of 0.1 ohm-cm silicon solar cells

    NASA Technical Reports Server (NTRS)

    Godlewski, M. P.; Brandhorst, H. W., Jr.; Lindholm, F. A.; Sah, C. T.

    1976-01-01

    An experimental method is presented that can be used to interpret the relative roles of bandgap narrowing and recombination processes in the diffused layer. This method involves measuring the device time constant by open-circuit voltage decay and the base region diffusion length by X-ray excitation. A unique illuminated diode method is used to obtain the diode saturation current. These data are interpreted using a simple model to determine individually the minority carrier lifetime and the excess charge. These parameters are then used to infer the relative importance of bandgap narrowing and recombination processes in the diffused layer.

  5. Formation of stable inverse sheath in ion–ion plasma by strong negative ion emission

    NASA Astrophysics Data System (ADS)

    Zhang, Zhe; Wu, Bang; Yang, Shali; Zhang, Ya; Chen, Dezhi; Fan, Mingwu; Jiang, Wei

    2018-06-01

    The effect of strong charged particle emission on plasma–wall interactions is a classical, yet unresolved question in plasma physics. Previous studies on secondary electron emission have shown that with different emission coefficients, there are classical, space-charge-limited, and inverse sheaths. In this letter, we demonstrate that a stable ion–ion inverse sheath and ion–ion plasma are formed with strong surface emission of negative ions. The continuous space-charge-limited to inverse ion–ion sheath transition is observed, and the plasma near the surface consequently transforms into pure ion–ion plasma. The results may explain the long-puzzled experimental observation that the density of negative ions depends on only charge not mass in negative ion sources.

  6. Electrostatic plasma lens for focusing negatively charged particle beams.

    PubMed

    Goncharov, A A; Dobrovolskiy, A M; Dunets, S M; Litovko, I V; Gushenets, V I; Oks, E M

    2012-02-01

    We describe the current status of ongoing research and development of the electrostatic plasma lens for focusing and manipulating intense negatively charged particle beams, electrons, and negative ions. The physical principle of this kind of plasma lens is based on magnetic isolation electrons providing creation of a dynamical positive space charge cloud in shortly restricted volume propagating beam. Here, the new results of experimental investigations and computer simulations of wide-aperture, intense electron beam focusing by plasma lens with positive space charge cloud produced due to the cylindrical anode layer accelerator creating a positive ion stream towards an axis system is presented.

  7. Mapping the Ice Depth of Europa with Ultrahigh Energy Particles

    NASA Astrophysics Data System (ADS)

    Romero-Wolf, A.; Naudet, C. J.

    2012-12-01

    There has been recent interest in applying radio emission of ultra-high energy neutrinos interacting in the ice of Europa. The idea was first described by Gorham (2004)[1] in the context of ultra-high energy particle detection. Shoji, Kurita, and Tanaka (2011)[2] proposed a technique for measuring ice depth using the radio intensity distribution of radio impulses emitted by interactions deep in the Europan ice. Miller, Schaefer, and Sequeira (2012)[3] follow up this study with a simulation of a radio detector mission to constrain the ice depth of Europa. The radio signal results from an effect proposed by Askar'yan (1962)[4] where the particle shower induced by the neutrino interaction accumulates a charge excess traveling faster than the speed of light in the medium and produces a coherent Cherenkov pulse at radio frequencies. We evaluate the feasibility of such a mission given the current state of knowledge of ultra-high energy particle detection and radio pulse production. References [1] Gorham (2004), Planet-sized Detectors for Ultra-high Energy Neutrinos & Cosmic Rays, NASA Advanced Planning Office's Capability Roadmap Public Workshop, Nov. 30, 2004, astro-ph/0411510 [2] Shoji, Kurita, and Tanaka (2011), Constraint of Europan ice thickness by measuring electromagnetic emissions induced by neutrino interaction, Geophysical Research Letters, 38, L08202 [3] Miller, Shaefer, Sequeira, PRIDE (Passive Radio [frequency] Ice Depth Experiment): An instrument to passively measure ice depth from a Europan orbiter using neutrinos, Icarus 220 877-888 [4] Askar'yan (1962), Excess negative charge of an electron photon shower and its coherent radiation originating from it. Radio recording of showers under the ground and on the Moon, Sov. Phys. JETP, 14, 441-443.

  8. Searches for new phenomena using events with three or more charged leptons in pp collisions at √s = 8 TeV with the ATLAS detector at the LHC

    NASA Astrophysics Data System (ADS)

    Yu, David Ren-Hwa

    This dissertation presents two searches for phenomena beyond the Standard Model using events with three or more charged leptons. The searches are based on 20.3 fb--1 of proton- proton collision data with a center-of-mass energy of [special characters omitted] s = 8 TeV collected by the ATLAS detector at the CERN Large Hadron Collider in 2012. The first is a model-independent search for excesses beyond Standard Model expectations in many signal regions. The events are required to have least three charged leptons, of which at least two are electrons or muons, and at most one is a hadronically decaying ? lepton. The selected events are categorized based on the flavor and charge of the leptons, and the signal regions are defined using several kinematic variables sensitive to beyond the Standard Model phenomena. The second search looks for new heavy leptons decaying resonantly to three electrons or muons, two of which are produced through an intermediate Z boson. The resonant decay produces a narrowly- peaked excess in the trilepton mass spectrum. In both cases, no significant excess beyond Standard Model expectations is observed, and the data are used to set limits on models of new physics. The model-independent trilepton search is used to confront a model of doubly charged scalar particles decaying to etau or mutau, excluding masses below 400 GeV at 95% confidence level. The trilepton resonance search is used to test models of vector-like leptons and the type III neutrino seesaw mechanism. The vector-like lepton model is excluded for most of the mass range 114 GeV -- 176 GeV, while the type III seesaw model is excluded for most the mass range 100 GeV -- 468 GeV. Both searches also present tools to facilitate reinterpretations in the context of other models predicting the production of three or more charged leptons.

  9. Electrochemical cell

    DOEpatents

    Redey, L.I.; Vissers, D.R.; Prakash, J.

    1994-02-01

    An electrochemical cell is described having a bimodal positive electrode, a negative electrode of an alkali metal, and a compatible electrolyte including an alkali metal salt molten at the cell operating temperature. The positive electrode has an electrochemically active layer of at least one transition metal chloride at least partially present as a charging product, and additives of bromide and/or iodide and sulfur in the positive electrode or the electrolyte. Electrode volumetric capacity is in excess of 400 Ah/cm[sup 3]; the cell can be 90% recharged in three hours and can operate at temperatures below 160 C. There is also disclosed a method of reducing the operating temperature and improving the overall volumetric capacity of an electrochemical cell and for producing a positive electrode having a BET area greater than 6[times]10[sup 4] cm[sup 2]/g of Ni. 8 figures.

  10. Electrochemical cell

    DOEpatents

    Redey, Laszlo I.; Vissers, Donald R.; Prakash, Jai

    1994-01-01

    An electrochemical cell having a bimodal positive electrode, a negative electrode of an alkali metal, and a compatible electrolyte including an alkali metal salt molten at the cell operating temperature. The positive electrode has an electrochemically active layer of at least one transition metal chloride at least partially present as a charging product, and additives of bromide and/or iodide and sulfur in the positive electrode or the electrolyte. Electrode volumetric capacity is in excess of 400 Ah/cm.sup.3 ; the cell can be 90% recharged in three hours and can operate at temperatures below 160.degree. C. There is also disclosed a method of reducing the operating temperature and improving the overall volumetric capacity of an electrochemical cell and for producing a positive electrode having a BET area greater than 6.times.10.sup.4 cm.sup.2 /g of Ni.

  11. Electrochemical cell

    DOEpatents

    Redey, Laszlo I.; Vissers, Donald R.; Prakash, Jai

    1996-01-01

    An electrochemical cell having a bimodal positive electrode, a negative electrode of an alkali metal, and a compatible electrolyte including an alkali metal salt molten at the cell operating temperature. The positive electrode has an electrochemically active layer of at least one transition metal chloride at least partially present as a charging product, and additives of bromide and/or iodide and sulfur in the positive electrode or the electrolyte. Electrode volumetric capacity is in excess of 400 Ah/cm.sup.3 ; the cell can be 90% recharged in three hours and can operate at temperatures below 160.degree. C. There is also disclosed a method of reducing the operating temperature and improving the overall volumetric capacity of an electrochemical cell and for producing a positive electrode having a BET area greater than 6.times.10.sup.4 cm.sup.2 /g of Ni.

  12. Electrochemical cell

    DOEpatents

    Redey, L.I.; Vissers, D.R.; Prakash, J.

    1996-07-16

    An electrochemical cell is described having a bimodal positive electrode, a negative electrode of an alkali metal, and a compatible electrolyte including an alkali metal salt molten at the cell operating temperature. The positive electrode has an electrochemically active layer of at least one transition metal chloride at least partially present as a charging product, and additives of bromide and/or iodide and sulfur in the positive electrode or the electrolyte. Electrode volumetric capacity is in excess of 400 Ah/cm{sup 3}; the cell can be 90% recharged in three hours and can operate at temperatures below 160 C. There is also disclosed a method of reducing the operating temperature and improving the overall volumetric capacity of an electrochemical cell and for producing a positive electrode having a BET area greater than 6{times}10{sup 4}cm{sup 2}/g of Ni. 6 figs.

  13. Analysis for nickel (3 and 4) in positive plates from nickel-cadmium cells

    NASA Technical Reports Server (NTRS)

    Lewis, Harlan L.

    1994-01-01

    The NASA-Goddard procedure for destructive physical analysis (DPA) of nickel-cadmium cells contains a method for analysis of residual charged nickel as NiOOH in the positive plates at complete cell discharge, also known as nickel precharge. In the method, the Ni(III) is treated with an excess of an Fe(II) reducing agent and then back titrated with permanganate. The Ni(III) content is the difference between Fe(II) equivalents and permanganate equivalents. Problems have arisen in analysis at NAVSURFWARCENDIV, Crane because for many types of cells, particularly AA-size and some 'space-qualified' cells, zero or negative Ni(III) contents are recorded for which the manufacturer claims 3-5 percent precharge. Our approach to this problem was to reexamine the procedure for the source of error, and correct it or develop an alternative method.

  14. Effect of charging on silicene with alkali metal atom adsorption

    NASA Astrophysics Data System (ADS)

    Li, Manman; Li, Zhongyao; Gong, Shi-Jing

    2018-02-01

    Based on first-principles calculations, we studied the effects of charging on the structure, binding energy and electronic properties of silicene with alkali metal (AM) atom (Li, Na or K) adsorption. In AMSi2, electron doping enlarges the lattice constant of silicene, while the influence of hole doping is non-monotonic. In AMSi8, the lattice constant increases/decreases almost linearly with the increase in electron/hole doping. In addition, the AM-Si vertical distance can be greatly enlarged by excessive hole doping in both AMSi2 and AMSi8 systems. When the hole doping is as large as  +e per unit cell, both AMSi2 and AMSi8 can be transformed from metal to semiconductor. However, the binding energy would be negative in the AM+ Si2 semiconductor. It suggests AM+ Si2 is unstable in this case. In addition, the electron doping and the AM-Si vertical distance would greatly influence the band gap of silicene in LiSi8 and NaSi8, while the band gap in KSi8 is relatively stable. Therefore, KSi8 may be a more practicable material in nanotechnology.

  15. Investigations on the defect dipole induced pyroelectric current in multiferroic GdMnO3 system

    NASA Astrophysics Data System (ADS)

    Pal, A.; Dhana Sekhar, C.; Venimadhav, A.; Prellier, W.; Murugavel, P.

    2018-01-01

    Pyroelectric current measurements on the orthorhombic GdMnO3 polycrystalline sample are done to explore the intrinsic and extrinsic contributions. The measurements reveal poling temperature dependent pyrocurrent peaks at 20, 50 and 108 K. The pyrocurrent at 20 K and at 108 K are attributed to ferroelectric transition induced by the incommensurate spiral magnetic ordering of Mn spins and the release of trapped charges from the localized states, respectively. A detailed analysis on the broad pyrocurrent signal at 50 K suggests that it could be attributed to the thermally stimulated depolarization current effect due to the relaxation of defect dipoles induced by negatively charged Mn3+ ions and excess holes localized at Mn4+ sites. Importantly, the effect of the electric field due to the defect dipoles on the ferroelectric state is highlighted. The temperature dependent dielectric measurements under the magnetic field brought out the correlation between pyroelectric and dielectric properties. The influence of poling temperature dependent extrinsic effects on pyrocurrent suggests the choice of poling temperature on the study of polarization and the resultant multiferroicity in a spin-driven ferroelectric rare earth manganite system.

  16. The influence of space charge shielding on dielectric multipactor

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Chang, C.; Liu, G. Z.; Tang, C. X.

    2009-05-15

    A model of space charge influenced by multipactor electrons and plasma has been established. The positive space charge potential/field for vacuum dielectric multipactor is analytically studied. After considering the plasma, the positive space charge field is further shielded, and multipactor saturates at higher surface accumulated field, compared with that for only considering multipactor electrons. The negative space charge potential/field for dielectric breakdown at high pressure is analyzed. It is found that the negative potential can be nonmonotonously varied, forming a minimum potential well.

  17. Physico-chemical studies on the interaction of dendrimers with lipid bilayers. 1. Effect of dendrimer generation and liposome surface charge.

    PubMed

    Roy, Biplab; Panda, Amiya Kumar; Parimi, Srinivas; Ametov, Igor; Barnes, Timothy; Prestidge, Clive A

    2014-01-01

    Studies on the interaction of different generation poly (amido amine) (PAMAM) dendrimers (2G, 4G and 6G) and liposomes of different compositions were carried out by a combined turbidity, dynamic light scattering and atomic force microscopic measurements. Liposomes comprising soy lecithin (SLC, negative surface charge), 1, 2-palmitoyl-sn-glycero-3-phosphatidylcholine (DPPC, mildly positive surface charge), 1,2-dipalmitoyl-sn-glycero-3-phospho-(1'-rac-glycerol (DPPG, negatively charged) and a biologically simulated mixture of DPPC + DPPG (7:3, M/M, negatively charged) were used as model bilayers. 30 wt% cholesterol was used in each combination as it is known to control the fluidity of membrane bilayers. Silica was used as a negatively charged hard sphere model with an aim to compare the results. Both the turbidity and hydrodynamic diameter values of all the liposomes, except DPPC, passed through maxima upon the progressive addition of PAMAM; the effect was insignificant in case of DPPC. Formation of dendriosome, a complex formed between dendrimer and liposome, resulted in the charge reversal of the negatively charged liposomes. Interaction between PAMAM and liposome was found to be governed by electrostatic as well as hydrogen bonding. Generation dependent PAMAM activity followed the order: 6G >4G>2G in terms of overall dendrimer concentration. However, interestingly, the order was reverse when PAMAM activity was considered in terms of total end group concentrations. AFM studies reveal the rupture of bilayer structure upon addition of dendrimer.

  18. Excitation of Kelvin Helmholtz instability by an ion beam in a plasma with negatively charged dust grains

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Rani, Kavita; Sharma, Suresh C.

    2015-02-15

    An ion beam propagating through a magnetized dusty plasma drives Kelvin Helmholtz Instability (KHI) via Cerenkov interaction. The frequency of the unstable wave increases with the relative density of negatively charged dust grains. It is observed that the beam has stabilizing effect on the growth rate of KHI for low shear parameter, but for high shear parameter, the instability is destabilized with relative density of negatively charged dust grains.

  19. Tribological Properties of Nanodiamonds in Aqueous Suspensions: Effect of the Surface Charge

    NASA Astrophysics Data System (ADS)

    Krim, J.; Liu, Zijian; Leininger, D. A.; Kooviland, A.; Smirnov, A. I.; Shendarova, O.; Brenner, D. W.

    The presence of granular nanoparticulates, be they wear particles created naturally by frictional rubbing at a geological fault line or products introduced as lubricant additives, can dramatically alter friction at solid-liquid interfaces. Given the complexity of such systems, understanding system properties at a fundamental level is particularly challenging. The Quartz Crystal Microbalance (QCM) is an ideal tool for studies of material-liquid-nanoparticulate interfaces. We have employed it here to study the uptake and nanotribological properties of positively and negatively charged 5-15 nm diameter nanodiamonds dispersed in water[1] in the both the presence and absence of a macroscopic contact with the QCM electrode. The nanodiamonds were found to impact tribological performance at both nanometer and macroscopic scales. The tribological effects were highly sensitive to the sign of the charge: negatively (positively) charged particles were more weakly (strongly) bound and reduced (increased) frictional drag at the solid-liquid interface. For the macroscopic contacts, negatively charged nanodiamonds appeared to be displaced from the contact, while the positively charged ones were not. Overall, the negatively charged nanodiamonds were more stable in an aqueous dispersion for extended time periods. Work supported by NSF and DOE.

  20. Effects of adhesions of amorphous Fe and Al hydroxides on surface charge and adsorption of K+ and Cd2+ on rice roots.

    PubMed

    Liu, Zhao-Dong; Wang, Hai-Cui; Zhou, Qin; Xu, Ren-Kou

    2017-11-01

    Iron (Fe) and aluminum (Al) hydroxides in variable charge soils attached to rice roots may affect surface-charge properties and subsequently the adsorption and uptake of nutrients and toxic metals by the roots. Adhesion of amorphous Fe and Al hydroxides onto rice roots and their effects on zeta potential of roots and adsorption of potassium (K + ) and cadmium (Cd 2+ ) by roots were investigated. Rice roots adsorbed more Al hydroxide than Fe hydroxide because of the greater positive charge on Al hydroxide. Adhesion of Fe and Al hydroxides decreased the negative charge on rice roots, and a greater effect of the Al hydroxide. Consequently, adhesion of Fe and Al hydroxides reduced the K + and Cd 2+ adsorption by rice roots. The results of attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR) and desorption of K + and Cd 2+ from rice roots indicated that physical masking by Fe and Al hydroxides and diffuse-layer overlapping between the positively-charged hydroxides and negatively-charged roots were responsible for the reduction of negative charge on roots induced by adhesion of the hydroxides. Therefore, the interaction between Fe and Al hydroxides and rice roots reduced negative charge on roots and thus inhibited their adsorption of nutrient and toxic cations. Copyright © 2017 Elsevier Inc. All rights reserved.

  1. Positive zeta potential of a negatively charged semi-permeable plasma membrane

    NASA Astrophysics Data System (ADS)

    Sinha, Shayandev; Jing, Haoyuan; Das, Siddhartha

    2017-08-01

    The negative charge of the plasma membrane (PM) severely affects the nature of moieties that may enter or leave the cells and controls a large number of ion-interaction-mediated intracellular and extracellular events. In this letter, we report our discovery of a most fascinating scenario, where one interface (e.g., membrane-cytosol interface) of the negatively charged PM shows a positive surface (or ζ) potential, while the other interface (e.g., membrane-electrolyte interface) still shows a negative ζ potential. Therefore, we encounter a completely unexpected situation where an interface (e.g., membrane-cytosol interface) that has a negative surface charge density demonstrates a positive ζ potential. We establish that the attainment of such a property by the membrane can be ascribed to an interplay of the nature of the membrane semi-permeability and the electrostatics of the electric double layer established on either side of the charged membrane. We anticipate that such a membrane property can lead to such capabilities of the cell (in terms of accepting or releasing certain kinds of moieties as well regulating cellular signaling) that was hitherto inconceivable.

  2. 75 FR 49849 - Defense Federal Acquisition Regulation Supplement; Excessive Pass-Through Charges (DFARS Case...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-08-16

    ..., and specifications; (2) Work itemized; (3) Place of performance of the work; (4) Time of commencement or completion of the work; and (5) Any other requirement of the job order. (b) If a change causes an... property made obsolete or excess as a result of a change, the Contracting Officer shall have the right to...

  3. 48 CFR 52.215-22 - Limitations on Pass-Through Charges-Identification of Subcontract Effort.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    .... The offeror's proposal shall exclude excessive pass-through charges. (c) Performance of work by the..., under the contract, task order, or delivery order. (2) If the offeror intends to subcontract more than 70 percent of the total cost of work to be performed under the contract, task order, or delivery...

  4. Effect of incorporation of nitrogen atoms in Al2O3 gate dielectric of wide-bandgap-semiconductor MOSFET on gate leakage current and negative fixed charge

    NASA Astrophysics Data System (ADS)

    Kojima, Eiji; Chokawa, Kenta; Shirakawa, Hiroki; Araidai, Masaaki; Hosoi, Takuji; Watanabe, Heiji; Shiraishi, Kenji

    2018-06-01

    We performed first-principle calculations to investigate the effect of incorporation of N atoms into Al2O3 gate dielectrics. Our calculations show that the defect levels generated by VO in Al2O3 are the origin of the stress-induced gate leakage current and that VOVAl complexes in Al2O3 cause negative fixed charge. We revealed that the incorporation of N atoms into Al2O3 eliminates the VO defect levels, reducing the stress-induced gate leakage current. Moreover, this suppresses the formation of negatively charged VOVAl complexes. Therefore, AlON can reduce both stress-induced gate leakage current and negative fixed charge in wide-bandgap-semiconductor MOSFETs.

  5. How did matter gain the upper hand over antimatter?

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Quinn, Helen; /SLAC

    2009-01-30

    Antimatter exists! We routinely make it in laboratories. For every familiar particle type we find a matching antiparticle with opposite charge, but exactly the same mass. For example, a positron with positive charge has the same mass as an electron; an antiproton with negative charge has the same mass as a proton. Antimatter occurs naturally all over the universe wherever high-energy particles collide. The laws of physics for antimatter are very, very similar to those for antimatter--so far we know only one tiny difference in them, a detail of the weak interactions of quarks that earned Makoto Kobayashi and Toshihidemore » Maskawa a share of the 2008 Nobel Prize for Physics. Our understanding of the early Universe also tells us that after inflation ended equal amounts of matter and antimatter were produced. Today there's a lot of matter in the universe, but very little antimatter. This leaves a big question for cosmology. How did matter gain the upper hand over antimatter? It's a question at the root of our existence. Without this excess, there would be no stars, no Earth, and no us! When a particle meets its antiparticle, they annihilate each other in a flash of radiation. This process removed all the antimatter and most of the matter as the universe expanded and cooled. All that's left today is the excess amount of matter when destruction began to dominate over production. To get from equality to inequality for matter and antimatter requires a difference in the laws of physics between them and some special situation where it affects the balance between them. But, when we try to use the tiny difference we know about between quark and antiquark weak interactions to generate the imbalance, it doesn't work. We find a way that it can indeed give a small excess of matter over antimatter, but not nearly enough to give us all the matter we see in our universe. We can patch up the theory by adding unknown particles to it to make a scenario that works. Indeed we can do that in two very different ways. One way adds more quark-antiquark differences. The other introduces a matter-antimatter difference that affects only neutrinos, ghostly subatomic particles that barely interact with matter. As yet we have no way to choose between these two speculative ideas; future experiments may help us decide between them.« less

  6. Anisotropy and chemical composition of ultra-high energy cosmic rays using arrival directions measured by the Pierre Auger Observatory

    DOE PAGES

    Abreu, P

    2011-06-17

    The Pierre Auger Collaboration has reported evidence for anisotropy in the distribution of arrival directions of the cosmic rays with energies E > E th = 5.5 x 10 19 eV. These show a correlation with the distribution of nearby extragalactic objects, including an apparent excess around the direction of Centaurus A. If the particles responsible for these excesses at E > E th are heavy nuclei with charge Z, the proton component of the sources should lead to excesses in the same regions at energies E/Z. We here report the lack of anisotropies in these directions at energies abovemore » E th/Z (for illustrative values of Z = 6,13,26). If the anisotropies above E th are due to nuclei with charge Z, and under reasonable assumptions about the acceleration process, these observations imply stringent constraints on the allowed proton fraction at the lower energies.« less

  7. Comment on 'The effect of liquid water on thunderstorm charging' by C.P.R. Saunders et al

    NASA Technical Reports Server (NTRS)

    Williams, Earle; Zhang, Renyi

    1993-01-01

    This paper is a comment on the claims made in the paper by Saunders et al. (1991), which reports on a laboratory simulation of ice particle charging in thunderstorms, concerning the microphysical condition of riming ice particles and the conditions for sublimation and negative charging in thunderclouds. It is argued that the interpretation of Saunders is contrary to the findings of Williams et al. (1991), which support the hypothesis that sublimating graupel charge negatively (in collision with smaller ice particles) and graupel in deposition charge positively. Based on microphysical calculations as well as observations in thunderclouds, it is concluded that, while sublimation of the rimer surface and negative charging do not appear to account for the laboratory observations reported by Saunders et al., these authors do not have sufficient evidence for rejecting the sublimation hypothesis presented by Williams et al. (1991) for thunderstorms.

  8. Electrostatic Power Generation from Negatively Charged, Simulated Lunar Regolith

    NASA Technical Reports Server (NTRS)

    Choi, Sang H.; King, Glen C.; Kim, Hyun-Jung; Park, Yeonjoon

    2010-01-01

    Research was conducted to develop an electrostatic power generator for future lunar missions that facilitate the utilization of lunar resources. The lunar surface is known to be negatively charged from the constant bombardment of electrons and protons from the solar wind. The resulting negative electrostatic charge on the dust particles, in the lunar vacuum, causes them to repel each other minimizing the potential. The result is a layer of suspended dust about one meter above the lunar surface. This phenomenon was observed by both Clementine and Surveyor spacecrafts. During the Apollo 17 lunar landing, the charged dust was a major hindrance, as it was attracted to the astronauts' spacesuits, equipment, and the lunar buggies. The dust accumulated on the spacesuits caused reduced visibility for the astronauts, and was unavoidably transported inside the spacecraft where it caused breathing irritation [1]. In the lunar vacuum, the maximum charge on the particles can be extremely high. An article in the journal "Nature", titled "Moon too static for astronauts?" (Feb 2, 2007) estimates that the lunar surface is charged with up to several thousand volts [2]. The electrostatic power generator was devised to alleviate the hazardous effects of negatively charged lunar soil by neutralizing the charged particles through capacitive coupling and thereby simultaneously harnessing power through electric charging [3]. The amount of power generated or collected is dependent on the areal coverage of the device and hovering speed over the lunar soil surface. A thin-film array of capacitors can be continuously charged and sequentially discharged using a time-differentiated trigger discharge process to produce a pulse train of discharge for DC mode output. By controlling the pulse interval, the DC mode power can be modulated for powering devices and equipment. In conjunction with a power storage system, the electrostatic power generator can be a power source for a lunar rover or other systems. The negatively charged lunar soil would also be neutralized mitigating some of the adverse effects resulting from lunar dust.

  9. Fuel mixture stratification as a method for improving homogeneous charge compression ignition engine operation

    DOEpatents

    Dec, John E [Livermore, CA; Sjoberg, Carl-Magnus G [Livermore, CA

    2006-10-31

    A method for slowing the heat-release rate in homogeneous charge compression ignition ("HCCI") engines that allows operation without excessive knock at higher engine loads than are possible with conventional HCCI. This method comprises injecting a fuel charge in a manner that creates a stratified fuel charge in the engine cylinder to provide a range of fuel concentrations in the in-cylinder gases (typically with enough oxygen for complete combustion) using a fuel with two-stage ignition fuel having appropriate cool-flame chemistry so that regions of different fuel concentrations autoignite sequentially.

  10. Protein charge distribution in proteomes and its impact on translation

    PubMed Central

    Requião, Rodrigo D.; Fernandes, Luiza; de Souza, Henrique José Araujo; Rossetto, Silvana; Domitrovic, Tatiana

    2017-01-01

    As proteins are synthesized, the nascent polypeptide must pass through a negatively charged exit tunnel. During this stage, positively charged stretches can interact with the ribosome walls and slow the translation. Therefore, charged polypeptides may be important factors that affect protein expression. To determine the frequency and distribution of positively and negatively charged stretches in different proteomes, the net charge was calculated for every 30 consecutive amino acid residues, which corresponds to the length of the ribosome exit tunnel. The following annotated and reviewed proteins in the UniProt database (Swiss-Prot) were analyzed: 551,705 proteins from different organisms and a total of 180 million protein segments. We observed that there were more negative than positive stretches and that super-charged positive sequences (i.e., net charges ≥ 14) were underrepresented in the proteomes. Overall, the proteins were more positively charged at their N-termini and C-termini, and this feature was present in most organisms and subcellular localizations. To investigate whether the N-terminal charges affect the elongation rates, previously published ribosomal profiling data obtained from S. cerevisiae, without translation-interfering drugs, were analyzed. We observed a nonlinear effect of the charge on the ribosome occupancy in which values ≥ +5 and ≤ -6 showed increased and reduced ribosome densities, respectively. These groups also showed different distributions across 80S monosomes and polysomes. Basic polypeptides are more common within short proteins that are translated by monosomes, whereas negative stretches are more abundant in polysome-translated proteins. These findings suggest that the nascent peptide charge impacts translation and can be one of the factors that regulate translation efficiency and protein expression. PMID:28531225

  11. On the Control of the Fixed Charge Densities in Al2O3-Based Silicon Surface Passivation Schemes.

    PubMed

    Simon, Daniel K; Jordan, Paul M; Mikolajick, Thomas; Dirnstorfer, Ingo

    2015-12-30

    A controlled field-effect passivation by a well-defined density of fixed charges is crucial for modern solar cell surface passivation schemes. Al2O3 nanolayers grown by atomic layer deposition contain negative fixed charges. Electrical measurements on slant-etched layers reveal that these charges are located within a 1 nm distance to the interface with the Si substrate. When inserting additional interface layers, the fixed charge density can be continuously adjusted from 3.5 × 10(12) cm(-2) (negative polarity) to 0.0 and up to 4.0 × 10(12) cm(-2) (positive polarity). A HfO2 interface layer of one or more monolayers reduces the negative fixed charges in Al2O3 to zero. The role of HfO2 is described as an inert spacer controlling the distance between Al2O3 and the Si substrate. It is suggested that this spacer alters the nonstoichiometric initial Al2O3 growth regime, which is responsible for the charge formation. On the basis of this charge-free HfO2/Al2O3 stack, negative or positive fixed charges can be formed by introducing additional thin Al2O3 or SiO2 layers between the Si substrate and this HfO2/Al2O3 capping layer. All stacks provide very good passivation of the silicon surface. The measured effective carrier lifetimes are between 1 and 30 ms. This charge control in Al2O3 nanolayers allows the construction of zero-fixed-charge passivation layers as well as layers with tailored fixed charge densities for future solar cell concepts and other field-effect based devices.

  12. Multiscale simulation reveals a multifaceted mechanism of proton permeation through the influenza A M2 proton channel

    PubMed Central

    Liang, Ruibin; Li, Hui; Swanson, Jessica M. J.; Voth, Gregory A.

    2014-01-01

    The influenza A virus M2 channel (AM2) is crucial in the viral life cycle. Despite many previous experimental and computational studies, the mechanism of the activating process in which proton permeation acidifies the virion to release the viral RNA and core proteins is not well understood. Herein the AM2 proton permeation process has been systematically characterized using multiscale computer simulations, including quantum, classical, and reactive molecular dynamics methods. We report, to our knowledge, the first complete free-energy profiles for proton transport through the entire AM2 transmembrane domain at various pH values, including explicit treatment of excess proton charge delocalization and shuttling through the His37 tetrad. The free-energy profiles reveal that the excess proton must overcome a large free-energy barrier to diffuse to the His37 tetrad, where it is stabilized in a deep minimum reflecting the delocalization of the excess charge among the histidines and the cost of shuttling the proton past them. At lower pH values the His37 tetrad has a larger total charge that increases the channel width, hydration, and solvent dynamics, in agreement with recent 2D-IR spectroscopic studies. The proton transport barrier becomes smaller, despite the increased charge repulsion, due to backbone expansion and the more dynamic pore water molecules. The calculated conductances are in quantitative agreement with recent experimental measurements. In addition, the free-energy profiles and conductances for proton transport in several mutants provide insights for explaining our findings and those of previous experimental mutagenesis studies. PMID:24979779

  13. Multiscale simulation reveals a multifaceted mechanism of proton permeation through the influenza A M2 proton channel.

    PubMed

    Liang, Ruibin; Li, Hui; Swanson, Jessica M J; Voth, Gregory A

    2014-07-01

    The influenza A virus M2 channel (AM2) is crucial in the viral life cycle. Despite many previous experimental and computational studies, the mechanism of the activating process in which proton permeation acidifies the virion to release the viral RNA and core proteins is not well understood. Herein the AM2 proton permeation process has been systematically characterized using multiscale computer simulations, including quantum, classical, and reactive molecular dynamics methods. We report, to our knowledge, the first complete free-energy profiles for proton transport through the entire AM2 transmembrane domain at various pH values, including explicit treatment of excess proton charge delocalization and shuttling through the His37 tetrad. The free-energy profiles reveal that the excess proton must overcome a large free-energy barrier to diffuse to the His37 tetrad, where it is stabilized in a deep minimum reflecting the delocalization of the excess charge among the histidines and the cost of shuttling the proton past them. At lower pH values the His37 tetrad has a larger total charge that increases the channel width, hydration, and solvent dynamics, in agreement with recent 2D-IR spectroscopic studies. The proton transport barrier becomes smaller, despite the increased charge repulsion, due to backbone expansion and the more dynamic pore water molecules. The calculated conductances are in quantitative agreement with recent experimental measurements. In addition, the free-energy profiles and conductances for proton transport in several mutants provide insights for explaining our findings and those of previous experimental mutagenesis studies.

  14. On charging of snow particles in blizzard

    NASA Technical Reports Server (NTRS)

    Shio, Hisashi

    1991-01-01

    The causes of the charge polarity on the blizzard, which consisted of fractured snow crystals and ice particles, were investigated. As a result, the charging phenomena showed that the characteristics of the blizzard are as follows: (1) In the case of the blizzard with snowfall, the fractured snow particles drifting near the surface of snow field (lower area: height 0.3 m) had positive charge, while those drifting at higher area (height 2 m) from the surface of snow field had negative charge. However, during the series of blizzards two kinds of particles positively and negatively charged were collected in equal amounts in a Faraday Cage. It may be considered that snow crystals with electrically neutral properties were separated into two kinds of snow flakes (charged positively and negatively) by destruction of the snow crystals. (2) In the case of the blizzard which consisted of irregularly formed ice drops (generated by peeling off the hardened snow field), the charge polarity of these ice drops salting over the snow field was particularly controlled by the crystallographic characteristics of the surface of the snow field hardened by the powerful wind pressure.

  15. Generating free charges by carrier multiplication in quantum dots for highly efficient photovoltaics.

    PubMed

    Ten Cate, Sybren; Sandeep, C S Suchand; Liu, Yao; Law, Matt; Kinge, Sachin; Houtepen, Arjan J; Schins, Juleon M; Siebbeles, Laurens D A

    2015-02-17

    CONSPECTUS: In a conventional photovoltaic device (solar cell or photodiode) photons are absorbed in a bulk semiconductor layer, leading to excitation of an electron from a valence band to a conduction band. Directly after photoexcitation, the hole in the valence band and the electron in the conduction band have excess energy given by the difference between the photon energy and the semiconductor band gap. In a bulk semiconductor, the initially hot charges rapidly lose their excess energy as heat. This heat loss is the main reason that the theoretical efficiency of a conventional solar cell is limited to the Shockley-Queisser limit of ∼33%. The efficiency of a photovoltaic device can be increased if the excess energy is utilized to excite additional electrons across the band gap. A sufficiently hot charge can produce an electron-hole pair by Coulomb scattering on a valence electron. This process of carrier multiplication (CM) leads to formation of two or more electron-hole pairs for the absorption of one photon. In bulk semiconductors such as silicon, the energetic threshold for CM is too high to be of practical use. However, CM in nanometer sized semiconductor quantum dots (QDs) offers prospects for exploitation in photovoltaics. CM leads to formation of two or more electron-hole pairs that are initially in close proximity. For photovoltaic applications, these charges must escape from recombination. This Account outlines our recent progress in the generation of free mobile charges that result from CM in QDs. Studies of charge carrier photogeneration and mobility were carried out using (ultrafast) time-resolved laser techniques with optical or ac conductivity detection. We found that charges can be extracted from photoexcited PbS QDs by bringing them into contact with organic electron and hole accepting materials. However, charge localization on the QD produces a strong Coulomb attraction to its counter charge in the organic material. This limits the production of free charges that can contribute to the photocurrent in a device. We show that free mobile charges can be efficiently produced via CM in solids of strongly coupled PbSe QDs. Strong electronic coupling between the QDs resulted in a charge carrier mobility of the order of 1 cm(2) V(-1) s(-1). This mobility is sufficiently high so that virtually all electron-hole pairs escape from recombination. The impact of temperature on the CM efficiency in PbSe QD solids was also studied. We inferred that temperature has no observable effect on the rate of cooling of hot charges nor on the CM rate. We conclude that exploitation of CM requires that charges have sufficiently high mobility to escape from recombination. The contribution of CM to the efficiency of photovoltaic devices can be further enhanced by an increase of the CM efficiency above the energetic threshold of twice the band gap. For large-scale applications in photovoltaic devices, it is important to develop abundant and nontoxic materials that exhibit efficient CM.

  16. NOVA SCIENCE UNIT 15, FUNDAMENTAL PARTICLES 4.

    ERIC Educational Resources Information Center

    1964

    THE PRINCIPLES OF ATOMIC STRUCTURE WHICH ARE STRESSED ARE THAT ATOMS ARE MADE UP OF A NUCLEUS WITH A POSITIVE CHARGE, SURROUNDED BY ELECTRONS WITH A NEGATIVE CHARGE, AND THAT THERE IS NO CHANGE IN THE ATOM WHEN THE POSITIVE AND NEGATIVE CHARGES ARE EQUAL. EXPERIMENTS ILLUSTRATE THAT CURRENT ELECTRICITY IS ACTUALLY ELECTRONS IN MOTION, THAT THERE…

  17. Weak-triplet, color-octet scalars and the CDF dijet excess

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Dobrescu, Bogdan A.; Krnjaic, Gordan Z.

    2012-04-24

    We extend the standard model to include a weak-triplet and color-octet scalar. This 'octo-triplet' field consists of three particles, two charged and one neutral, whose masses and renormalizable interactions depend only on two new parameters. The charged octo-triplet decay into a W boson and a gluon is suppressed by a loop factor and an accidental cancellation. Thus, the main decays of the charged octo-triplet may occur through higher-dimensional operators, mediated by a heavy vectorlike fermion, into quark pairs. For an octo-triplet mass below the tb¯ threshold, the decay into Wb b¯ through an off-shell top quark has a width comparablemore » to that into cs¯ or cb¯. Pair production with one octo-triplet decaying to two jets and the other decaying to a W and two soft b jets may explain the dijet-plus-W excess reported by the CDF Collaboration. The same higher-dimensional operators lead to CP violation in B s-B¯ s mixing.« less

  18. Building health: The need for electromagnetic hygiene?

    NASA Astrophysics Data System (ADS)

    Jamieson, Isaac A.; Holdstock, Paul; ApSimon, Helen M.; Bell, J. Nigel B.

    2010-04-01

    Whilst the electromagnetic nature of the built environment has changed considerably over the past century, little thought is at present given to the possible advantages of creating electromagnetic microenvironments that more closely resemble those found in nature and/or developing biologically-friendly technology aligned more closely to its operating principles. This review paper examines how more natural exposures to a variety of electromagnetic phenomena could be re-introduced into the built environment, possible benefits that might arise, and discusses the extent to which there may be tangible benefits obtainable from introducing more rigorous properly considered electromagnetic hygiene measures. Amongst the matters discussed are: the effects of different materials, finishes and electrical items on charge generation (and the effects of excess charge on contaminant deposition); the possible benefits of suitably grounding conductive objects (including humans) in order to reduce excess charge and contaminant deposition; how the presence of vertical electric field regimes, similar to those found in nature, may enhance biological performance; and possible pitfalls to avoid when seeking to introduce appropriate electromagnetic hygiene regimes.

  19. DOE Office of Scientific and Technical Information (OSTI.GOV)

    Dalchenko, Mykhailo; Dutta, Bhaskar; Gao, Yu

    The recent diphoton excess at the LHC has been explained tentatively by a Standard Model (SM) singlet scalar of 750 GeV in mass, in the association of heavy particles with SM gauge charges. These new particles with various SM gauge charges induce loop-level couplings of the new scalar to WW, ZZ, Zγ, γγ, and gg. Here, we show that the strength of the couplings to the gauge bosons also determines the production mechanism of the scalar particle via WW,ZZ,Zγ,γγ,gg fusion which leads to individually distinguishable jet distributions in the final state where the statistics will be improved in the ongoingmore » run. Finally, the number of jets and the leading jet's transverse momentum distribution in the excess region of the diphoton signal can be used to determine the coupling of the scalar to the gauge bosons arising from the protons which subsequently determine the charges of the heavy particles that arise from various well-motivated models.« less

  20. Formation of redox gradients during magma-magma mixing

    NASA Astrophysics Data System (ADS)

    Ruprecht, P.; Fiege, A.; Simon, A. C.

    2015-12-01

    Magma-mixing is a key process that controls mass transfer in magmatic systems. The variations in melt compositions near the magma-magma interface potentially change the Fe oxidation state [1] and, thus, affect the solubility and transport of metals. To test this hypothesis, diffusion-couple experiments were performed at 1000 °C, 150 MPa and QFM+4. Synthesized crystal-bearing cylinders of hydrous dacite and hydrous basaltic andesite were equilibrated for up to 80 h. The run products show that mafic components (Fe, Mg, etc.) were transported from the andesite into the dacite, while Si, Na and K diffused from the dacite into the andesite. A crystal dissolution sequence in the order of cpx, opx, plag, and spl/il was observed for the andesite. We combined μ-XANES spectroscopy at Fe K-edge [2] with two-oxide oxybarometry [3] to measure redox profiles within our experiments. Here, fO2 decreased towards the interface within the dacite and increased towards the interface within the andesite. This discontinuous fO2 evolution, with a sharp redox gradient of ~1.8 log fO2 units at the interface was maintained throughout the time-series despite the externally imposed fO2 of the vessel. We propose a combination of two mechanisms that create and sustain this redox gradient: 1) The dissolution of cpx and opx in the andesite mainly introduced Fe2+ into the melt, which diffused towards the dacite, lowering Fe3+/SFe near the interface. 2) Charge balance calculations in the melt during diffusive exchange suggest net positive charge excess in the andesite near the interface (i.e., oxidation) and net negative charge excess in the dacite near the interface (i.e., reduction). We suggest that this (metastable) redox layer can help to explain the contrasting Au/Cu ratios observed for arc-related porphyry-type ore deposits. [1] Moretti (2005), Ann. Geophys. 48, 583-608. [2] Cottrell et al. (2009), Chem. Geol. 268, 167-179. [3] Ghiorso and Evans (2008), Am. J. Sci. 308, 957-1039.

  1. 20 CFR 404.435 - Excess earnings; months to which excess earnings can or cannot be charged; grace year defined.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... reason of having a child in his or her care), or to mother's or father's benefits is entitled to a...: Marion was entitled to mother's insurance benefits from 1998 because she had a child in her care. Because... 2000, and the child's benefits terminated in April 2000. Marion's entitlement to mother's benefits also...

  2. The surface charge of trypanosomatids.

    PubMed

    Souto-Padrón, Thaïs

    2002-12-01

    The surface charge of trypanosomatids was evaluated by means of the binding of cationic particles, as visualized by electron microscopy and by direct measurements of the electrophoretic mobility of cells. The results obtained indicate that most of the trypanosomatids exhibit a negatively charged surface whose value is species specific and varies according to the developmental stages. Sialic acids associated with glycoproteins, glycolipids and phosphate groups are the major components responsible for the net negative surface charge of the trypanosomatids.

  3. Borophene as a Promising Material for Charge-Modulated Switchable CO2 Capture.

    PubMed

    Tan, Xin; Tahini, Hassan A; Smith, Sean C

    2017-06-14

    Ideal carbon dioxide (CO 2 ) capture materials for practical applications should bind CO 2 molecules neither too weakly to limit good loading kinetics nor too strongly to limit facile release. Although charge-modulated switchable CO 2 capture has been proposed to be a controllable, highly selective, and reversible CO 2 capture strategy, the development of a practical gas-adsorbent material remains a great challenge. In this study, by means of density functional theory (DFT) calculations, we have examined the possibility of conductive borophene nanosheets as promising sorbent materials for charge-modulated switchable CO 2 capture. Our results reveal that the binding strength of CO 2 molecules on negatively charged borophene can be significantly enhanced by injecting extra electrons into the adsorbent. At saturation CO 2 capture coverage, the negatively charged borophene achieves CO 2 capture capacities up to 6.73 × 10 14 cm -2 . In contrast to the other CO 2 capture methods, the CO 2 capture/release processes on negatively charged borophene are reversible with fast kinetics and can be easily controlled via switching on/off the charges carried by borophene nanosheets. Moreover, these negatively charged borophene nanosheets are highly selective for separating CO 2 from mixtures with CH 4 , H 2 , and/or N 2 . This theoretical exploration will provide helpful guidance for identifying experimentally feasible, controllable, highly selective, and high-capacity CO 2 capture materials with ideal thermodynamics and reversibility.

  4. Mechanisms of Polyelectrolyte Enhanced Surfactant Adsorption at the Air-Water Interface

    PubMed Central

    Stenger, Patrick C.; Palazoglu, Omer A.; Zasadzinski, Joseph A.

    2009-01-01

    Chitosan, a naturally occurring cationic polyelectrolyte, restores the adsorption of the clinical lung surfactant Survanta to the air-water interface in the presence of albumin at much lower concentrations than uncharged polymers such as polyethylene glycol. This is consistent with the positively charged chitosan forming ion pairs with negative charges on the albumin and lung surfactant particles, reducing the net charge in the double-layer, and decreasing the electrostatic energy barrier to adsorption to the air-water interface. However, chitosan, like other polyelectrolytes, cannot perfectly match the charge distribution on the surfactant, which leads to patches of positive and negative charge at net neutrality. Increasing the chitosan concentration further leads to a reduction in the rate of surfactant adsorption consistent with an over-compensation of the negative charge on the surfactant and albumin surfaces, which creates a new repulsive electrostatic potential between the now cationic surfaces. This charge neutralization followed by charge inversion explains the window of polyelectrolyte concentration that enhances surfactant adsorption; the same physical mechanism is observed in flocculation and re-stabilization of anionic colloids by chitosan and in alternate layer deposition of anionic and cationic polyelectrolytes on charged colloids. PMID:19366599

  5. Mechanisms of polyelectrolyte enhanced surfactant adsorption at the air-water interface.

    PubMed

    Stenger, Patrick C; Palazoglu, Omer A; Zasadzinski, Joseph A

    2009-05-01

    Chitosan, a naturally occurring cationic polyelectrolyte, restores the adsorption of the clinical lung surfactant Survanta to the air-water interface in the presence of albumin at much lower concentrations than uncharged polymers such as polyethylene glycol. This is consistent with the positively charged chitosan forming ion pairs with negative charges on the albumin and lung surfactant particles, reducing the net charge in the double-layer, and decreasing the electrostatic energy barrier to adsorption to the air-water interface. However, chitosan, like other polyelectrolytes, cannot perfectly match the charge distribution on the surfactant, which leads to patches of positive and negative charge at net neutrality. Increasing the chitosan concentration further leads to a reduction in the rate of surfactant adsorption consistent with an over-compensation of the negative charge on the surfactant and albumin surfaces, which creates a new repulsive electrostatic potential between the now cationic surfaces. This charge neutralization followed by charge inversion explains the window of polyelectrolyte concentration that enhances surfactant adsorption; the same physical mechanism is observed in flocculation and re-stabilization of anionic colloids by chitosan and in alternate layer deposition of anionic and cationic polyelectrolytes on charged colloids.

  6. Electrostatic control of phospholipid polymorphism.

    PubMed

    Tarahovsky, Y S; Arsenault, A L; MacDonald, R C; McIntosh, T J; Epand, R M

    2000-12-01

    A regular progression of polymorphic phase behavior was observed for mixtures of the anionic phospholipid, cardiolipin, and the cationic phospholipid derivative, 1, 2-dioleoyl-sn-glycero-3-ethylphosphocholine. As revealed by freeze-fracture electron microscopy and small-angle x-ray diffraction, whereas the two lipids separately assume only lamellar phases, their mixtures exhibit a symmetrical (depending on charge ratio and not polarity) sequence of nonlamellar phases. The inverted hexagonal phase, H(II,) formed from equimolar mixtures of the two lipids, i.e., at net charge neutrality (charge ratio (CR((+/-))) = 1:1). When one type of lipid was in significant excess (CR((+/-)) = 2:1 or CR((+/-)) = 1:2), a bicontinuous cubic structure was observed. These cubic phases were very similar to those sometimes present in cellular organelles that contain cardiolipin. Increasing the excess of cationic or anionic charge to CR((+/-)) = 4:1 or CR((+/-)) = 1:4 led to the appearance of membrane bilayers with numerous interlamellar contacts, i.e., sponge structures. It is evident that interactions between cationic and anionic moieties can influence the packing of polar heads and hence control polymorphic phase transitions. The facile isothermal, polymorphic interconversion of these lipids may have important biological and technical implications.

  7. Charge Dynamics and Bending Actuation in Aquivion Membrane Swelled with Ionic Liquids.

    PubMed

    Lin, Junhong; Liu, Yang; Zhang, Q M

    2011-01-21

    The actuation strain and speed of ionic electroactive polymer (EAP) actuators are mainly determined by the charge transport through the actuators and excess ion storage near the electrodes. We employ a recently developed theory on ion transport and storage to investigate the charge dynamics of short-side-chain Aquivion® (Hyflon®) membranes with different uptakes of ionic liquid (IL) 1-ethyl-3-methylimidazolium trifluoromethanesulfonate (EMI-Tf). The results reveal the existence of a critical uptake of ionic liquids above which the membrane exhibit a high ionic conductivity (σ>5×10(-2) mS/cm). Especially, we investigate the charge dynamics under voltages which are in the range for practical device operation (~1 volts and higher). The results show that the ionic conductivity, ionic mobility, and mobile ion concentration do not change with the applied voltage below 1 volt (and for σ below 4 volts). The results also show that bending actuation of the Aquivion membrane with 40 wt% EMI-Tf is much larger than that of Nafion, indicating that the shorter flexible side chains improve the electromechanical coupling between the excess ions and the membrane backbones, while not affect the actuation speed.

  8. Charge Dynamics and Bending Actuation in Aquivion Membrane Swelled with Ionic Liquids

    PubMed Central

    Lin, Junhong; Liu, Yang; Zhang, Q. M.

    2011-01-01

    The actuation strain and speed of ionic electroactive polymer (EAP) actuators are mainly determined by the charge transport through the actuators and excess ion storage near the electrodes. We employ a recently developed theory on ion transport and storage to investigate the charge dynamics of short-side-chain Aquivion® (Hyflon®) membranes with different uptakes of ionic liquid (IL) 1-ethyl-3-methylimidazolium trifluoromethanesulfonate (EMI-Tf). The results reveal the existence of a critical uptake of ionic liquids above which the membrane exhibit a high ionic conductivity (σ>5×10−2 mS/cm). Especially, we investigate the charge dynamics under voltages which are in the range for practical device operation (~1 volts and higher). The results show that the ionic conductivity, ionic mobility, and mobile ion concentration do not change with the applied voltage below 1 volt (and for σ below 4 volts). The results also show that bending actuation of the Aquivion membrane with 40 wt% EMI-Tf is much larger than that of Nafion, indicating that the shorter flexible side chains improve the electromechanical coupling between the excess ions and the membrane backbones, while not affect the actuation speed. PMID:21339839

  9. Coarse-grained modeling of proline rich protein 1 (PRP-1) in bulk solution and adsorbed to a negatively charged surface.

    PubMed

    Skepö, Marie; Linse, Per; Arnebrant, Thomas

    2006-06-22

    Structural properties of the acidic proline rich protein PRP-1 of salivary origin in bulk solution and adsorbed onto a negatively charged surface have been studied by Monte Carlo simulations. A simple model system with focus on electrostatic interactions and short-ranged attractions among the uncharged amino acids has been used. In addition to PRP-1, some mutants were considered to assess the role of the interactions in the systems. Contrary to polyelectrolytes, the protein has a compact structure in salt-free bulk solutions, whereas at high salt concentration the protein becomes more extended. The protein adsorbs to a negatively charged surface, although its net charge is negative. The adsorbed protein displays an extended structure, which becomes more compact upon addition of salt. Hence, the conformational response upon salt addition in the adsorbed state is the opposite as compared to that in bulk solution. The conformational behavior of PRP-1 in bulk solution and at charged surfaces as well as its propensity to adsorb to surfaces with the same net charge are rationalized by the block polyampholytic character of the protein. The presence of a triad of positively charged amino acids in the C-terminal was found to be important for the adsorption of the protein.

  10. VHF lightning mapping observations of a triggered lightning flash

    NASA Astrophysics Data System (ADS)

    Edens, H. E.; Eack, K. B.; Eastvedt, E. M.; Trueblood, J. J.; Winn, W. P.; Krehbiel, P. R.; Aulich, G. D.; Hunyady, S. J.; Murray, W. C.; Rison, W.; Behnke, S. A.; Thomas, R. J.

    2012-10-01

    On 3 August 2010 an extensive lightning flash was triggered over Langmuir Laboratory in New Mexico. The upward positive leader propagated into the storm's midlevel negative charge region, extending over a horizontal area of 13 × 13 km and 7.5 km altitude. The storm had a normal-polarity tripolar charge structure with upper positive charge over midlevel negative charge. Lightning Mapping Array (LMA) observations were used to estimate positive leader velocities along various branches, which were in the range of 1-3 × 104 m s-1, slower than in other studies. The upward positive leader initiated at 3.4 km altitude, but was mapped only above 4.0 km altitude after the onset of retrograde negative breakdown, indicating a change in leader propagation and VHF emissions. The observations suggest that both positive and negative breakdown produce VHF emissions that can be located by time-of-arrival systems, and that not all VHF emissions occurring along positive leader channels are associated with retrograde negative breakdown.

  11. X-Pol Potential: An Electronic Structure-Based Force Field for Molecular Dynamics Simulation of a Solvated Protein in Water.

    PubMed

    Xie, Wangshen; Orozco, Modesto; Truhlar, Donald G; Gao, Jiali

    2009-02-17

    A recently proposed electronic structure-based force field called the explicit polarization (X-Pol) potential is used to study many-body electronic polarization effects in a protein, in particular by carrying out a molecular dynamics (MD) simulation of bovine pancreatic trypsin inhibitor (BPTI) in water with periodic boundary conditions. The primary unit cell is cubic with dimensions ~54 × 54 × 54 Å(3), and the total number of atoms in this cell is 14281. An approximate electronic wave function, consisting of 29026 basis functions for the entire system, is variationally optimized to give the minimum Born-Oppenheimer energy at every MD step; this allows the efficient evaluation of the required analytic forces for the dynamics. Intramolecular and intermolecular polarization and intramolecular charge transfer effects are examined and are found to be significant; for example, 17 out of 58 backbone carbonyls differ from neutrality on average by more than 0.1 electron, and the average charge on the six alanines varies from -0.05 to +0.09. The instantaneous excess charges vary even more widely; the backbone carbonyls have standard deviations in their fluctuating net charges from 0.03 to 0.05, and more than half of the residues have excess charges whose standard deviation exceeds 0.05. We conclude that the new-generation X-Pol force field permits the inclusion of time-dependent quantum mechanical polarization and charge transfer effects in much larger systems than was previously possible.

  12. Influences of Excess Oscillation of Voltage Pulse and Discharge Mode on NO Removal Using Barrier-Type Plasma Reactor

    NASA Astrophysics Data System (ADS)

    Kadowaki, Kazunori; Suzuki, Yoshiaki; Ihori, Haruo; Kitani, Isamu

    This paper presents experimental results of NO removal from a simulated exhausted-gas using a barrier type reactor with screw electrodes subjected to polarity-reversed voltage pulses. The polarity-reversed pulse was produced by direct grounding of a charged coaxial cable because a traveling wave voltage was negatively reflected at the grounding end with a change in its polarity and then it propagated to the plasma reactor at the opposite end. Influence of cable length on NO removal was studied for two kinds of cable connection, single-connected cable and parallel-connected cables. NO removal ratio for a 50m-long cable was lower than that for much shorter cables in both single and parallel connections when the applied voltage became high. Energy efficiency for NO removal also increased with decreasing the cable length. This was because excess discharges during the voltage oscillation caused by the large stored energy in the long cable resulted in reproduction of NO molecules. Energy efficiency was further improved by changing the discharge mode from dielectric barrier discharge (DBD) to surface discharge (SD). Energy efficiency was up to 110g/kWh with 55% NO removal ratio and 34g/kWh with 100% NO removal ratio by using a single 10m-long cable in SD mode.

  13. NMSSM interpretation of the Galactic Center excess

    NASA Astrophysics Data System (ADS)

    Cheung, Clifford; Papucci, Michele; Sanford, David; Shah, Nausheen R.; Zurek, Kathryn M.

    2014-10-01

    We explore models for the GeV Galactic Center excess (GCE) observed by the Fermi Telescope, focusing on χχ→ff ¯ annihilation processes in the Z3 next-to-minimal supersymmetric standard model (NMSSM). We begin by examining the requirements for a simplified model [parametrized by the couplings and masses of dark matter (DM) and mediator particles] to reproduce the GCE via χχ→ff ¯, while simultaneously thermally producing the observed relic abundance. We apply the results of our simplified model to the Z3 NMSSM for singlino/Higgsino (S/H) or bino/Higgsino (B/H) DM. In the case of S/H DM, we find that the DM must be very close to a pseudoscalar resonance to be viable, and large tanβ and positive values of μ are preferred for evading direct detection constraints while simultaneously obtaining the observed Higgs mass. In the case of B/H DM, by contrast, the situation is much less tuned: annihilation generally occurs off resonance, and for large tanβ, direct detection constraints are easily satisfied by choosing μ sufficiently large and negative. The B/H model generally has a light, largely MSSM-like pseudoscalar with no accompanying charged Higgs, which could be searched for at the LHC.

  14. Potentiometric and spectroscopic study of the interaction of 3d transition metal ions with inositol hexakisphosphate

    NASA Astrophysics Data System (ADS)

    Veiga, Nicolás; Macho, Israel; Gómez, Kerman; González, Gabriel; Kremer, Carlos; Torres, Julia

    2015-10-01

    Among myo-inositol phosphates, the most abundant in nature is the myo-inositol hexakisphosphate, InsP6. Although it is known to be vital to cell functioning, the biochemical research into its metabolism needs chemical and structural analysis of all the protonation, complexation and precipitation processes that it undergoes in the biological media. In view of its high negative charge at physiological level, our group has been leading a thorough research into the InsP6 chemical and structural behavior in the presence of the alkali and alkaline earth metal ions essential for life. The aim of this article is to extend these studies, dealing with the chemical and structural features of the InsP6 interaction with biologically relevant 3d transition metal ions (Fe(II), Fe(III), Mn(II), Co(II), Ni(II), Cu(II) and Zn(II)), in a non-interacting medium and under simulated physiological conditions. The metal-complex stability constants were determined by potentiometry, showing under ligand-excess conditions the formation of mononuclear species in different protonation states. Under metal ion excess, polymetallic species were detected for Fe(II), Fe(III), Zn(II) and Cu(II). Additionally, the 31P NMR and UV-vis spectroscopic studies provided interesting structural aspects of the strong metal ion-InsP6 interaction.

  15. The role of surface charge on the uptake and biocompatibility of hydroxyapatite nanoparticles with osteoblast cells

    PubMed Central

    Chen, Liang; Mccrate, Joseph M.; Lee, James C-M.; Li, Hao

    2011-01-01

    The objective of this study is to evaluate the effect of hydroxyapatite (HAP) nanoparticles with different surface charges on the cellular uptake behavior and in vitro cell viability and proliferation of MC3T3-E1 cell lines (osteoblast). The nanoparticles surface charge was varied by the surface modification with two carboxylic acids: 12-aminododecanoic acid (positive) and dodecanedioic acid (negative). The untreated HAP nanoparticles and dodecanoic acid modified HAP nanoparticles (neutral) were used as the control. X-ray diffraction (XRD) revealed that surface modifications by the three carboxylic acids did not change the crystal structure of HAP nanoparticles; Fourier transform infrared spectroscopy (FTIR) confirmed the adsorption and binding of the carboxylic acids on HAP nanoparticle surface; and zeta potential measurement confirmed that the chemicals successfully modified the surface charge of HAP nanoparticles in water based solution. Transmission electron microscopy (TEM) images showed that positively charged, negatively charged and untreated HAP nanoparticles, with similar size and shape, all penetrated into the cells and cells had more uptake of HAP nanoparticles with positive charge compared to those with negative charge, which might be attributed to the attractive or repulsive interaction between the negatively charged cell membrane and positively/negatively charged HAP nanoparticles. The neutral HAP nanoparticles could not penetrate cell membrane due to the larger size. MTT assay and LDH assay results indicated that as compared with the polystyrene control, greater cell viability and cell proliferation were measured on MC3T3-E1 cells treated with the three kinds of the HAP nanoparticles (neutral, positive, and untreated), among which positively charged HAP nanoparticles shows strongest improvement for cell viability and cell proliferation. In summary, the surface charge of HAP nanoparticles can be modified to influence the cellular uptake of HAP nanoparticles and the different uptake also influence the behavior of cells. These in-vitro results may also provide useful information for investigations of HAP nanoparticles applications in the gene delivery and intracellular drug delivery. PMID:21289408

  16. In situ measurements and radar observations of a severe storm - Electricity, kinematics, and precipitation

    NASA Technical Reports Server (NTRS)

    Byrne, G. J.; Few, A. A.; Stewart, M. F.; Conrad, A. C.; Torczon, R. L.

    1987-01-01

    Electric field measurements made inside a multicell severe storm in Oklahoma in 1983 with a balloon-borne instrument are presented. The properties of the electric charge regions, such as altitude, thickness, and charge concentrations, are studied. These measurements are analzyed with meteorological measurements of temperature and humidity, and balloon tracking and radar observations. The relation between the electric charge structure and the precipitation and kinematic features of the storm is examined. The data reveal that the cell exhibits a bipolar charge structure with negative charge below positive charge. The average charge concentrations of the two regions are estimated as -1.2 and 0.15 nC/cu m, respectively; the upper positive charge is about 6 km in vertical extent, and the lower negative charge is less than 1 km in vertical extent.

  17. Positively versus negatively charged moral emotion expectancies in adolescence: the role of situational context and the developing moral self.

    PubMed

    Krettenauer, Tobias; Johnston, Megan

    2011-09-01

    The study analyses adolescents' positively charged versus negatively charged moral emotion expectancies. Two hundred and five students (M= 14.83 years, SD= 2.21) participated in an interview depicting various situations in which a moral norm was either regarded or transgressed. Emotion expectancies were assessed for specific emotions (pride, guilt) as well as for overall strength and valence. In addition, self-importance of moral values was measured by a questionnaire. Results revealed that positively charged emotion expectancies were more pronounced in contexts of prosocial action than in the context of moral transgressions, whereas the opposite was true for negatively charged emotions. At the same time, expectations of guilt and pride were substantially related to the self-importance of moral values. ©2010 The British Psychological Society.

  18. Charge rearrangement deduced from nearby electric field measurements of an intracloud flash with K‒changes

    NASA Astrophysics Data System (ADS)

    Hager, William W.; Feng, Wei

    2013-09-01

    An intracloud flash near Langmuir Laboratory is analyzed to determine the net rearrangement of charge. The analysis employed data from a balloon borne electric field sensor, or Esonde, that was within a few hundred meters of the lightning channel, data from a similar Esonde on a mountain about 6.4 km from the balloon, and data from the New Mexico Institute of Mining and Technology Lightning Mapping Array (LMA). The recovery of the charge transport required the solution of Poisson's equation over the mountainous terrain surrounding Langmuir Laboratory and the solution of a vastly under‒determined system of equations. The charge movement is analyzed using a new smooth charge transport model that incorporates constraints in the least squares fitting process through the use of penalty terms to smooth the charge movement and prevent data overfitting. The electric field measurements were consistent with about 26% of the negative charge being transported to the end of the channel, 36% deposited along the channel in the positive region, 8% deposited near the start of the channel in the positive region, and 30% deposited in another positive region several kilometers beneath the main channel. The transport of negative charge to a lower positive region occurred during the K‒processes when some negative charge was also deposited along the main channel in the upper positive region. Hence, the charge transport process during the K‒processes amounted to a tripolar charge rearrangement where the charge from the negative region was transported to two distinct positive regions, the positive region along the main channel and a lower positive region beneath the main channel. High altitude, widely scattered LMA sources beyond the end of the main channel could indicate the existence of streamers which transported the end‒of‒channel charge into the surrounding volume. Although the LMA showed the development of two upper channels, the charge transport analysis showed that measurable charge transport only occurred on one of the channels. The channel that did not transport charge was missing the high altitude, widely scattered LMA sources seen at the end of the channel that carried charge.

  19. Effect of User Charges on Secondary Level Surgical Care Utilization and Out-of-Pocket Expenditures in Haryana State, India.

    PubMed

    Balasubramanian, Deepak; Prinja, Shankar; Aggarwal, Arun Kumar

    2015-01-01

    Generation of resources for providing health care services is an important issue in developing countries. User charges in the form of Surgical Package Program (SPP) were introduced in all district hospitals of Haryana to address this problem. We evaluate the effect of this SPP program on surgical care utilization and out-of-pocket (OOP) expenditures. Data on 25437 surgeries, from July 2006 to June 2013 in 3 districts of Haryana state, was analyzed using interrupted time series analysis to assess the impact of SPP on utilization of services. Adjustment was made for presence of any autocorrelation and seasonality effects. A cross sectional survey was undertaken among 180 patients in District hospital, Panchkula during June 2013 to assess the extent of out of pocket (OOP) expenditure incurred, financial risk protection and methods to cope with OOP expenditure. Catastrophic health expenditure, estimated as any expenditure in excess of 10% of the household consumption expenditure, was used to assess the extent of financial risk protection. User charges had a negative effect on the number of surgeries in public sector district hospitals in all the 3 districts. The mean out-of-pocket expenditure incurred by the patients was Rs.4564 (USD 74.6). The prevalence of catastrophic expenditure was 5.6%. A higher proportion among the poorest 20% population coped through borrowing money (47.2%), while majority (86.1%) of those belonging to richest quintile paid from their monthly income or savings, or had insurance. There is a need to increase the public financing for curative services and it should be based on the needs of population. Any form of user charge in public sector hospitals should be removed.

  20. Tool Helps Utilities Assess Readiness for Electric Vehicle Charging (Fact Sheet)

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Not Available

    NREL research helps answer a fundamental question regarding electric vehicles: Is the grid ready to handle them? Environmental, economic and security concerns regarding oil consumption make electrifying the transportation sector a high national priority. NREL's Center for Transportation Technologies & Systems (CTTS) has developed a framework for utilities to evaluate the plug-in vehicle (PEV) readiness of distribution transformers. Combining a wealth of vehicle performance statistics with load data from partner utilities including the Hawaiian Electric Company and Xcel Energy, NREL analyzed the thermal loading characteristics of distribution transformers due to vehicle charging. After running millions of simulations replicating varying climatesmore » and conditions, NREL is now able to predict aging rates for transformers when PEVs are added to existing building loads. With the NREL tool, users define simulation parameters by inputting vehicle trip and weather data; transformer load profiles and ratings; PEV penetration, charging rates and battery sizes; utility rates; the number of houses on each transformer; and public charging availability. Transformer load profiles, drive cycles, and ambient temperature data are then run through the thermal model to produce a one-year timeseries of the hotspot temperature. Annual temperature durations are calculated to help determine the annual aging rate. Annual aging rate results are grouped by independent variables. The most useful measure is transformer mileage, a measure of how many electrically-driven miles must be supplied by the transformer. Once the spectrum analysis has been conducted for an area or utility, the outputs can be used to help determine if more detailed evaluation is necessary, or if transformer replacement is required. In the majority of scenarios, transformers have enough excess capacity to charge PEVs. Only in extreme cases does vehicle charging have negative long-term impact on transformers. In those cases, upgrades to larger transformers would be recommended. NREL analysis also showed opportunity for newly-installed smart grids to offset distribution demands by time-shifting the charging loads. Most importantly, the model demonstrated synergies between PEVs and distributed renewables, not only providing clean renewable energy for vehicles, but also reducing demand on the entire distribution infrastructure by supplying loads at the point of consumption.« less

  1. Characteristic study of head-on collision of dust-ion acoustic solitons of opposite polarity with kappa distributed electrons

    NASA Astrophysics Data System (ADS)

    Parveen, Shahida; Mahmood, Shahzad; Adnan, Muhammad; Qamar, Anisa

    2016-09-01

    The head on collision between two dust ion acoustic (DIA) solitary waves, propagating in opposite directions, is studied in an unmagnetized plasma constituting adiabatic ions, static dust charged (positively/negatively) grains, and non-inertial kappa distributed electrons. In the linear limit, the dispersion relation of the dust ion acoustic (DIA) solitary wave is obtained using the Fourier analysis. For studying characteristic head-on collision of DIA solitons, the extended Poincaré-Lighthill-Kuo method is employed to obtain Korteweg-de Vries (KdV) equations with quadratic nonlinearities and investigated the phase shifts in their trajectories after the interaction. It is revealed that only compressive solitary waves can exist for the positive dust charged concentrations while for negative dust charge concentrations both the compressive and rarefactive solitons can propagate in such dusty plasma. It is found that for specific sets of plasma parameters, the coefficient of nonlinearity disappears in the KdV equation for the negative dust charged grains. Therefore, the modified Korteweg-de Vries (mKdV) equations with cubic nonlinearity coefficient, and their corresponding phase shift and trajectories, are also derived for negative dust charged grains plasma at critical composition. The effects of different plasma parameters such as superthermality, concentration of positively/negatively static dust charged grains, and ion to electron temperature ratio on the colliding soliton profiles and their corresponding phase shifts are parametrically examined.

  2. A Unified Model of Cloud-to-Ground Lightning Stroke

    NASA Astrophysics Data System (ADS)

    Nag, A.; Rakov, V. A.

    2014-12-01

    The first stroke in a cloud-to-ground lightning discharge is thought to follow (or be initiated by) the preliminary breakdown process which often produces a train of relatively large microsecond-scale electric field pulses. This process is poorly understood and rarely modeled. Each lightning stroke is composed of a downward leader process and an upward return-stroke process, which are usually modeled separately. We present a unified engineering model for computing the electric field produced by a sequence of preliminary breakdown, stepped leader, and return stroke processes, serving to transport negative charge to ground. We assume that a negatively-charged channel extends downward in a stepped fashion through the relatively-high-field region between the main negative and lower positive charge centers and then through the relatively-low-field region below the lower positive charge center. A relatively-high-field region is also assumed to exist near ground. The preliminary breakdown pulse train is assumed to be generated when the negatively-charged channel interacts with the lower positive charge region. At each step, an equivalent current source is activated at the lower extremity of the channel, resulting in a step current wave that propagates upward along the channel. The leader deposits net negative charge onto the channel. Once the stepped leader attaches to ground (upward connecting leader is presently neglected), an upward-propagating return stroke is initiated, which neutralizes the charge deposited by the leader along the channel. We examine the effect of various model parameters, such as step length and current propagation speed, on model-predicted electric fields. We also compare the computed fields with pertinent measurements available in the literature.

  3. Carbon nanotubes' surface chemistry determines their potency as vaccine nanocarriers in vitro and in vivo

    PubMed Central

    Hassan, Hatem A.F.M.; Smyth, Lesley; Rubio, Noelia; Ratnasothy, Kulachelvy; Wang, Julie T.-W.; Bansal, Sukhvinder S.; Summers, Huw D.; Diebold, Sandra S.; Lombardi, Giovanna; Al-Jamal, Khuloud T.

    2016-01-01

    Carbon nanotubes (CNTs) have shown marked capabilities in enhancing antigen delivery to antigen presenting cells. However, proper understanding of how altering the physical properties of CNTs may influence antigen uptake by antigen presenting cells, such as dendritic cells (DCs), has not been established yet. We hypothesized that altering the physical properties of multi-walled CNTs (MWNTs)-antigen conjugates, e.g. length and surface charge, can affect the internalization of MWNT-antigen by DCs, hence the induced immune response potency. For this purpose, pristine MWNTs (p-MWNTs) were exposed to various chemical reactions to modify their physical properties then conjugated to ovalbumin (OVA), a model antigen. The yielded MWNTs-OVA conjugates were long MWNT-OVA (~ 386 nm), bearing net positive charge (5.8 mV), or short MWNTs-OVA (~ 122 nm) of increasing negative charges (− 23.4, − 35.8 or − 39 mV). Compared to the short MWNTs-OVA bearing high negative charges, short MWNT-OVA with the lowest negative charge demonstrated better cellular uptake and OVA-specific immune response both in vitro and in vivo. However, long positively-charged MWNT-OVA showed limited cellular uptake and OVA specific immune response in contrast to short MWNT-OVA displaying the least negative charge. We suggest that reduction in charge negativity of MWNT-antigen conjugate enhances cellular uptake and thus the elicited immune response intensity. Nevertheless, length of MWNT-antigen conjugate might also affect the cellular uptake and immune response potency; highlighting the importance of physical properties as a consideration in designing a MWNT-based vaccine delivery system. PMID:26802552

  4. Interactions of microbicide nanoparticles with a simulated vaginal fluid.

    PubMed

    das Neves, José; Rocha, Cristina M R; Gonçalves, Maria Pilar; Carrier, Rebecca L; Amiji, Mansoor; Bahia, Maria Fernanda; Sarmento, Bruno

    2012-11-05

    The interaction with cervicovaginal mucus presents the potential to impact the performance of drug nanocarriers. These systems must migrate through this biological fluid in order to deliver their drug payload to the underlying mucosal surface. We studied the ability of dapivirine-loaded polycaprolactone (PCL)-based nanoparticles (NPs) to interact with a simulated vaginal fluid (SVF) incorporating mucin. Different surface modifiers were used to produce NPs with either negative (poloxamer 338 NF and sodium lauryl sulfate) or positive (cetyltrimethylammonium bromide) surface charge. Studies were performed using the mucin particle method, rheological measurements, and real-time multiple particle tracking. Results showed that SVF presented rheological properties similar to those of human cervicovaginal mucus. Analysis of NP transport indicated mild interactions with mucin and low adhesive potential. In general, negatively charged NPs underwent subdiffusive transport in SVF, i.e., hindered as compared to their diffusion in water, but faster than for positively charged NPs. These differences were increased when the pH of SVF was changed from 4.2 to 7.0. Diffusivity was 50- and 172-fold lower in SVF at pH 4.2 than in water for negatively charged and positively charged NPs, respectively. At pH 7.0, this decrease was around 20- and 385-fold, respectively. The estimated times required to cross a layer of SVF were equal to or lower than 1.7 h for negatively charged NPs, while for positively charged NPs these values were equal to or higher than 7 h. Overall, our results suggest that negatively charged PCL NPs may be suitable to be used as carriers in order to deliver dapivirine and potentially other antiretroviral drugs to the cervicovaginal mucosal lining. Also, they further reinforce the importance in characterizing the interactions of nanosystems with mucus fluids or surrogates when considering mucosal drug delivery.

  5. Intracellular sorting of differently charged chitosan derivatives and chitosan-based nanoparticles

    NASA Astrophysics Data System (ADS)

    Zubareva, A. A.; Shcherbinina, T. S.; Varlamov, V. P.; Svirshchevskaya, E. V.

    2015-04-01

    Chitosan (Chi) is a biodegradable nontoxic polycation with multiple reactive groups that is easily used to obtain derivatives with a desired charge and hydrophobic properties. The aim of this work was to study the intracellular traffic of positively charged hexanoyl-chitosan (HC) or HC-based nanoparticles (HCNPs) and negatively charged succinoyl-chitosan (SC) and SCNPs in epithelial and macrophage cell lines. By using flow cytometry we demonstrated that positively charged HC adhered to cell membranes quicker and more efficiently than negatively charged SC or NPs. However confocal studies showed that SC and SCNPs penetrated cells much more efficiently than HC while HCNPs did not enter the epithelial cells. Macrophages also phagocyted better negatively charged material but were able to engulf both HC and HCNPs. Upon entering the cells, SC and SCNPs were co-localized with endosomes and lysosomes while HC was found in mitochondria and, to a lesser extent, in lysosomes of epithelial cells. Macrophages, RAW264.7, more efficiently transported all Chi samples to the lysosomal compartment while some positively charged material was still found in mitochondria. Incubation of Chi derivatives and ChiNPs at pH specific to mitochondria (8.0) and lysosomes (4.5) demonstrated the neutralization of Chi charge. We concluded that epithelial cells and, to a lesser extent, macrophages sort charged material to the organelles neutralizing Chi charge.

  6. Comparing Positively and Negatively Charged Distonic Radical Ions in Phenylperoxyl Forming Reactions.

    PubMed

    Williams, Peggy E; Marshall, David L; Poad, Berwyck L J; Narreddula, Venkateswara R; Kirk, Benjamin B; Trevitt, Adam J; Blanksby, Stephen J

    2018-06-04

    In the gas phase, arylperoxyl forming reactions play a significant role in low-temperature combustion and atmospheric processing of volatile organic compounds. We have previously demonstrated the application of charge-tagged phenyl radicals to explore the outcomes of these reactions using ion trap mass spectrometry. Here, we present a side-by-side comparison of rates and product distributions from the reaction of positively and negatively charge tagged phenyl radicals with dioxygen. The negatively charged distonic radical ions are found to react with significantly greater efficiency than their positively charged analogues. The product distributions of the anion reactions favor products of phenylperoxyl radical decomposition (e.g., phenoxyl radicals and cyclopentadienone), while the comparable fixed-charge cations yield the stabilized phenylperoxyl radical. Electronic structure calculations rationalize these differences as arising from the influence of the charged moiety on the energetics of rate-determining transition states and reaction intermediates within the phenylperoxyl reaction manifold and predict that this influence could extend to intra-molecular charge-radical separations of up to 14.5 Å. Experimental observations of reactions of the novel 4-(1-carboxylatoadamantyl)phenyl radical anion confirm that the influence of the charge on both rate and product distribution can be modulated by increasing the rigidly imposed separation between charge and radical sites. These findings provide a generalizable framework for predicting the influence of charged groups on polarizable radicals in gas phase distonic radical ions. Graphical Abstract.

  7. Comparing Positively and Negatively Charged Distonic Radical Ions in Phenylperoxyl Forming Reactions

    NASA Astrophysics Data System (ADS)

    Williams, Peggy E.; Marshall, David L.; Poad, Berwyck L. J.; Narreddula, Venkateswara R.; Kirk, Benjamin B.; Trevitt, Adam J.; Blanksby, Stephen J.

    2018-06-01

    In the gas phase, arylperoxyl forming reactions play a significant role in low-temperature combustion and atmospheric processing of volatile organic compounds. We have previously demonstrated the application of charge-tagged phenyl radicals to explore the outcomes of these reactions using ion trap mass spectrometry. Here, we present a side-by-side comparison of rates and product distributions from the reaction of positively and negatively charge tagged phenyl radicals with dioxygen. The negatively charged distonic radical ions are found to react with significantly greater efficiency than their positively charged analogues. The product distributions of the anion reactions favor products of phenylperoxyl radical decomposition (e.g., phenoxyl radicals and cyclopentadienone), while the comparable fixed-charge cations yield the stabilized phenylperoxyl radical. Electronic structure calculations rationalize these differences as arising from the influence of the charged moiety on the energetics of rate-determining transition states and reaction intermediates within the phenylperoxyl reaction manifold and predict that this influence could extend to intra-molecular charge-radical separations of up to 14.5 Å. Experimental observations of reactions of the novel 4-(1-carboxylatoadamantyl)phenyl radical anion confirm that the influence of the charge on both rate and product distribution can be modulated by increasing the rigidly imposed separation between charge and radical sites. These findings provide a generalizable framework for predicting the influence of charged groups on polarizable radicals in gas phase distonic radical ions.

  8. Detecting negative ions on board small satellites

    NASA Astrophysics Data System (ADS)

    Lepri, S. T.; Raines, J. M.; Gilbert, J. A.; Cutler, J.; Panning, M.; Zurbuchen, T. H.

    2017-04-01

    Recent measurements near comets, planets, and their satellites have shown that heavy ions, energetic neutral atoms, molecular ions, and charged dust contain a wealth of information about the origin, evolution, and interaction of celestial bodies with their space environment. Using highly sensitive plasma instruments, positively charged heavy ions have been used to trace exospheric and surface composition of comets, planets, and satellites as well as the composition of interplanetary and interstellar dust. While positive ions dominate throughout the heliosphere, negative ions are also produced from surface interactions. In fact, laboratory experiments have shown that oxygen released from rocky surfaces is mostly negatively charged. Negative ions and negatively charged nanograins have been detected with plasma electron analyzers in several different environments (e.g., by Cassini and Rosetta), though more extensive studies have been challenging without instrumentation dedicated to negative ions. We discuss an adaptation of the Fast Imaging Plasma Spectrometer (FIPS) flown on MErcury Surface, Space ENvironment, GEochemistry and Ranging (MESSENGER) for the measurement of negatively charged particles. MESSENGER/FIPS successfully measured the plasma environment of Mercury from 2011 until 2015, when the mission ended, and has been used to map multiple ion species (H+ through Na+ and beyond) throughout Mercury's space environment. Modifications to the existing instrument design fits within a 3U CubeSat volume and would provide a low mass, low power instrument, ideal for future CubeSat or distributed sensor missions seeking, for the first time, to characterize the contribution of negative particles in the heliospheric plasmas near the planets, moons, comets, and other sources.

  9. Correlations between jets and charged particles in PbPb and pp collisions at √{s_{NN}}=2.76 TeV

    NASA Astrophysics Data System (ADS)

    Khachatryan, V.; Sirunyan, A. M.; Tumasyan, A.; Adam, W.; Asilar, E.; Bergauer, T.; Brandstetter, J.; Brondolin, E.; Dragicevic, M.; Erö, J.; Flechl, M.; Friedl, M.; Frühwirth, R.; Ghete, V. M.; Hartl, C.; Hörmann, N.; Hrubec, J.; Jeitler, M.; Knünz, V.; König, A.; Krammer, M.; Krätschmer, I.; Liko, D.; Matsushita, T.; Mikulec, I.; Rabady, D.; Rad, N.; Rahbaran, B.; Rohringer, H.; Schieck, J.; Schöfbeck, R.; Strauss, J.; Treberer-Treberspurg, W.; Waltenberger, W.; Wulz, C.-E.; Mossolov, V.; Shumeiko, N.; Suarez Gonzalez, J.; Alderweireldt, S.; Cornelis, T.; de Wolf, E. A.; Janssen, X.; Knutsson, A.; Lauwers, J.; Luyckx, S.; van de Klundert, M.; van Haevermaet, H.; van Mechelen, P.; van Remortel, N.; van Spilbeeck, A.; Abu Zeid, S.; Blekman, F.; D'Hondt, J.; Daci, N.; de Bruyn, I.; Deroover, K.; Heracleous, N.; Keaveney, J.; Lowette, S.; Moreels, L.; Olbrechts, A.; Python, Q.; Strom, D.; Tavernier, S.; van Doninck, W.; van Mulders, P.; van Onsem, G. P.; van Parijs, I.; Barria, P.; Brun, H.; Caillol, C.; Clerbaux, B.; de Lentdecker, G.; Fasanella, G.; Favart, L.; Goldouzian, R.; Grebenyuk, A.; Karapostoli, G.; Lenzi, T.; Léonard, A.; Maerschalk, T.; Marinov, A.; Perniè, L.; Randle-Conde, A.; Seva, T.; Vander Velde, C.; Vanlaer, P.; Yonamine, R.; Zenoni, F.; Zhang, F.; Beernaert, K.; Benucci, L.; Cimmino, A.; Crucy, S.; Dobur, D.; Fagot, A.; Garcia, G.; Gul, M.; McCartin, J.; Ocampo Rios, A. A.; Poyraz, D.; Ryckbosch, D.; Salva, S.; Sigamani, M.; Tytgat, M.; van Driessche, W.; Yazgan, E.; Zaganidis, N.; Basegmez, S.; Beluffi, C.; Bondu, O.; Brochet, S.; Bruno, G.; Caudron, A.; Ceard, L.; Delaere, C.; Favart, D.; Forthomme, L.; Giammanco, A.; Jafari, A.; Jez, P.; Komm, M.; Lemaitre, V.; Mertens, A.; Musich, M.; Nuttens, C.; Perrini, L.; Piotrzkowski, K.; Popov, A.; Quertenmont, L.; Selvaggi, M.; Vidal Marono, M.; Beliy, N.; Hammad, G. H.; Aldá Júnior, W. L.; Alves, F. L.; Alves, G. A.; Brito, L.; Correa Martins Junior, M.; Hamer, M.; Hensel, C.; Moraes, A.; Pol, M. E.; Rebello Teles, P.; Belchior Batista Das Chagas, E.; Carvalho, W.; Chinellato, J.; Custódio, A.; da Costa, E. M.; de Jesus Damiao, D.; de Oliveira Martins, C.; Fonseca de Souza, S.; Huertas Guativa, L. M.; Malbouisson, H.; Matos Figueiredo, D.; Mora Herrera, C.; Mundim, L.; Nogima, H.; Prado da Silva, W. L.; Santoro, A.; Sznajder, A.; Tonelli Manganote, E. J.; Vilela Pereira, A.; Ahuja, S.; Bernardes, C. A.; de Souza Santos, A.; Dogra, S.; Fernandez Perez Tomei, T. R.; Gregores, E. M.; Mercadante, P. G.; Moon, C. S.; Novaes, S. F.; Padula, Sandra S.; Romero Abad, D.; Ruiz Vargas, J. C.; Aleksandrov, A.; Hadjiiska, R.; Iaydjiev, P.; Rodozov, M.; Stoykova, S.; Sultanov, G.; Vutova, M.; Dimitrov, A.; Glushkov, I.; Litov, L.; Pavlov, B.; Petkov, P.; Ahmad, M.; Bian, J. G.; Chen, G. M.; Chen, H. S.; Chen, M.; Cheng, T.; Du, R.; Jiang, C. H.; Leggat, D.; Plestina, R.; Romeo, F.; Shaheen, S. M.; Spiezia, A.; Tao, J.; Wang, C.; Wang, Z.; Zhang, H.; Asawatangtrakuldee, C.; Ban, Y.; Li, Q.; Liu, S.; Mao, Y.; Qian, S. J.; Wang, D.; Xu, Z.; Avila, C.; Cabrera, A.; Chaparro Sierra, L. F.; Florez, C.; Gomez, J. P.; Gomez Moreno, B.; Sanabria, J. C.; Godinovic, N.; Lelas, D.; Puljak, I.; Ribeiro Cipriano, P. M.; Antunovic, Z.; Kovac, M.; Brigljevic, V.; Kadija, K.; Luetic, J.; Micanovic, S.; Sudic, L.; Attikis, A.; Mavromanolakis, G.; Mousa, J.; Nicolaou, C.; Ptochos, F.; Razis, P. A.; Rykaczewski, H.; Bodlak, M.; Finger, M.; Finger, M.; Abdelalim, A. A.; Awad, A.; Mahrous, A.; Radi, A.; Calpas, B.; Kadastik, M.; Murumaa, M.; Raidal, M.; Tiko, A.; Veelken, C.; Eerola, P.; Pekkanen, J.; Voutilainen, M.; Härkönen, J.; Karimäki, V.; Kinnunen, R.; Lampén, T.; Lassila-Perini, K.; Lehti, S.; Lindén, T.; Luukka, P.; Peltola, T.; Tuominen, E.; Tuominiemi, J.; Tuovinen, E.; Wendland, L.; Talvitie, J.; Tuuva, T.; Besancon, M.; Couderc, F.; Dejardin, M.; Denegri, D.; Fabbro, B.; Faure, J. L.; Favaro, C.; Ferri, F.; Ganjour, S.; Givernaud, A.; Gras, P.; Hamel de Monchenault, G.; Jarry, P.; Locci, E.; Machet, M.; Malcles, J.; Rander, J.; Rosowsky, A.; Titov, M.; Zghiche, A.; Antropov, I.; Baffioni, S.; Beaudette, F.; Busson, P.; Cadamuro, L.; Chapon, E.; Charlot, C.; Davignon, O.; Filipovic, N.; Granier de Cassagnac, R.; Jo, M.; Lisniak, S.; Mastrolorenzo, L.; Miné, P.; Naranjo, I. N.; Nguyen, M.; Ochando, C.; Ortona, G.; Paganini, P.; Pigard, P.; Regnard, S.; Salerno, R.; Sauvan, J. B.; Sirois, Y.; Strebler, T.; Yilmaz, Y.; Zabi, A.; Agram, J.-L.; Andrea, J.; Aubin, A.; Bloch, D.; Brom, J.-M.; Buttignol, M.; Chabert, E. C.; Chanon, N.; Collard, C.; Conte, E.; Coubez, X.; Fontaine, J.-C.; Gelé, D.; Goerlach, U.; Goetzmann, C.; Le Bihan, A.-C.; Merlin, J. A.; Skovpen, K.; van Hove, P.; Gadrat, S.; Beauceron, S.; Bernet, C.; Boudoul, G.; Bouvier, E.; Carrillo Montoya, C. A.; Chierici, R.; Contardo, D.; Courbon, B.; Depasse, P.; El Mamouni, H.; Fan, J.; Fay, J.; Gascon, S.; Gouzevitch, M.; Ille, B.; Lagarde, F.; Laktineh, I. B.; Lethuillier, M.; Mirabito, L.; Pequegnot, A. L.; Perries, S.; Ruiz Alvarez, J. D.; Sabes, D.; Sgandurra, L.; Sordini, V.; Vander Donckt, M.; Verdier, P.; Viret, S.; Toriashvili, T.; Tsamalaidze, Z.; Autermann, C.; Beranek, S.; Feld, L.; Heister, A.; Kiesel, M. K.; Klein, K.; Lipinski, M.; Ostapchuk, A.; Preuten, M.; Raupach, F.; Schael, S.; Schulte, J. F.; Verlage, T.; Weber, H.; Zhukov, V.; Ata, M.; Brodski, M.; Dietz-Laursonn, E.; Duchardt, D.; Endres, M.; Erdmann, M.; Erdweg, S.; Esch, T.; Fischer, R.; Güth, A.; Hebbeker, T.; Heidemann, C.; Hoepfner, K.; Knutzen, S.; Kreuzer, P.; Merschmeyer, M.; Meyer, A.; Millet, P.; Mukherjee, S.; Olschewski, M.; Padeken, K.; Papacz, P.; Pook, T.; Radziej, M.; Reithler, H.; Rieger, M.; Scheuch, F.; Sonnenschein, L.; Teyssier, D.; Thüer, S.; Cherepanov, V.; Erdogan, Y.; Flügge, G.; Geenen, H.; Geisler, M.; Hoehle, F.; Kargoll, B.; Kress, T.; Künsken, A.; Lingemann, J.; Nehrkorn, A.; Nowack, A.; Nugent, I. M.; Pistone, C.; Pooth, O.; Stahl, A.; Aldaya Martin, M.; Asin, I.; Bartosik, N.; Behnke, O.; Behrens, U.; Borras, K.; Burgmeier, A.; Campbell, A.; Contreras-Campana, C.; Costanza, F.; Diez Pardos, C.; Dolinska, G.; Dooling, S.; Dorland, T.; Eckerlin, G.; Eckstein, D.; Eichhorn, T.; Flucke, G.; Gallo, E.; Garay Garcia, J.; Geiser, A.; Gizhko, A.; Gunnellini, P.; Hauk, J.; Hempel, M.; Jung, H.; Kalogeropoulos, A.; Karacheban, O.; Kasemann, M.; Katsas, P.; Kieseler, J.; Kleinwort, C.; Korol, I.; Lange, W.; Leonard, J.; Lipka, K.; Lobanov, A.; Lohmann, W.; Mankel, R.; Melzer-Pellmann, I.-A.; Meyer, A. B.; Mittag, G.; Mnich, J.; Mussgiller, A.; Naumann-Emme, S.; Nayak, A.; Ntomari, E.; Perrey, H.; Pitzl, D.; Placakyte, R.; Raspereza, A.; Roland, B.; Sahin, M. Ö.; Saxena, P.; Schoerner-Sadenius, T.; Seitz, C.; Spannagel, S.; Trippkewitz, K. D.; Walsh, R.; Wissing, C.; Blobel, V.; Centis Vignali, M.; Draeger, A. R.; Erfle, J.; Garutti, E.; Goebel, K.; Gonzalez, D.; Görner, M.; Haller, J.; Hoffmann, M.; Höing, R. S.; Junkes, A.; Klanner, R.; Kogler, R.; Kovalchuk, N.; Lapsien, T.; Lenz, T.; Marchesini, I.; Marconi, D.; Meyer, M.; Nowatschin, D.; Ott, J.; Pantaleo, F.; Peiffer, T.; Perieanu, A.; Pietsch, N.; Poehlsen, J.; Rathjens, D.; Sander, C.; Scharf, C.; Schleper, P.; Schlieckau, E.; Schmidt, A.; Schumann, S.; Schwandt, J.; Sola, V.; Stadie, H.; Steinbrück, G.; Stober, F. M.; Tholen, H.; Troendle, D.; Usai, E.; Vanelderen, L.; Vanhoefer, A.; Vormwald, B.; Barth, C.; Baus, C.; Berger, J.; Böser, C.; Butz, E.; Chwalek, T.; Colombo, F.; de Boer, W.; Descroix, A.; Dierlamm, A.; Fink, S.; Frensch, F.; Friese, R.; Giffels, M.; Gilbert, A.; Haitz, D.; Hartmann, F.; Heindl, S. M.; Husemann, U.; Katkov, I.; Kornmayer, A.; Lobelle Pardo, P.; Maier, B.; Mildner, H.; Mozer, M. U.; Müller, T.; Müller, Th.; Plagge, M.; Quast, G.; Rabbertz, K.; Röcker, S.; Roscher, F.; Schröder, M.; Sieber, G.; Simonis, H. J.; Ulrich, R.; Wagner-Kuhr, J.; Wayand, S.; Weber, M.; Weiler, T.; Williamson, S.; Wöhrmann, C.; Wolf, R.; Anagnostou, G.; Daskalakis, G.; Geralis, T.; Giakoumopoulou, V. A.; Kyriakis, A.; Loukas, D.; Psallidas, A.; Topsis-Giotis, I.; Agapitos, A.; Kesisoglou, S.; Panagiotou, A.; Saoulidou, N.; Tziaferi, E.; Evangelou, I.; Flouris, G.; Foudas, C.; Kokkas, P.; Loukas, N.; Manthos, N.; Papadopoulos, I.; Paradas, E.; Strologas, J.; Bencze, G.; Hajdu, C.; Hazi, A.; Hidas, P.; Horvath, D.; Sikler, F.; Veszpremi, V.; Vesztergombi, G.; Zsigmond, A. J.; Beni, N.; Czellar, S.; Karancsi, J.; Molnar, J.; Szillasi, Z.; Bartók, M.; Makovec, A.; Raics, P.; Trocsanyi, Z. L.; Ujvari, B.; Choudhury, S.; Mal, P.; Mandal, K.; Sahoo, D. K.; Sahoo, N.; Swain, S. K.; Bansal, S.; Beri, S. B.; Bhatnagar, V.; Chawla, R.; Gupta, R.; Bhawandeep, U.; Kalsi, A. K.; Kaur, A.; Kaur, M.; Kumar, R.; Mehta, A.; Mittal, M.; Singh, J. B.; Walia, G.; Kumar, Ashok; Bhardwaj, A.; Choudhary, B. C.; Garg, R. B.; Malhotra, S.; Naimuddin, M.; Nishu, N.; Ranjan, K.; Sharma, R.; Sharma, V.; Bhattacharya, S.; Chatterjee, K.; Dey, S.; Dutta, S.; Majumdar, N.; Modak, A.; Mondal, K.; Mukhopadhyay, S.; Roy, A.; Roy, D.; Roy Chowdhury, S.; Sarkar, S.; Sharan, M.; Abdulsalam, A.; Chudasama, R.; Dutta, D.; Jha, V.; Kumar, V.; Mohanty, A. K.; Pant, L. M.; Shukla, P.; Topkar, A.; Aziz, T.; Banerjee, S.; Bhowmik, S.; Chatterjee, R. M.; Dewanjee, R. K.; Dugad, S.; Ganguly, S.; Ghosh, S.; Guchait, M.; Gurtu, A.; Jain, Sa.; Kole, G.; Kumar, S.; Mahakud, B.; Maity, M.; Majumder, G.; Mazumdar, K.; Mitra, S.; Mohanty, G. B.; Parida, B.; Sarkar, T.; Sur, N.; Sutar, B.; Wickramage, N.; Chauhan, S.; Dube, S.; Kapoor, A.; Kothekar, K.; Sharma, S.; Bakhshiansohi, H.; Behnamian, H.; Etesami, S. M.; Fahim, A.; Khakzad, M.; Mohammadi Najafabadi, M.; Naseri, M.; Paktinat Mehdiabadi, S.; Rezaei Hosseinabadi, F.; Safarzadeh, B.; Zeinali, M.; Felcini, M.; Grunewald, M.; Abbrescia, M.; Calabria, C.; Caputo, C.; Colaleo, A.; Creanza, D.; Cristella, L.; de Filippis, N.; de Palma, M.; Fiore, L.; Iaselli, G.; Maggi, G.; Maggi, M.; Miniello, G.; My, S.; Nuzzo, S.; Pompili, A.; Pugliese, G.; Radogna, R.; Ranieri, A.; Selvaggi, G.; Silvestris, L.; Venditti, R.; Abbiendi, G.; Battilana, C.; Benvenuti, A. C.; Bonacorsi, D.; Braibant-Giacomelli, S.; Brigliadori, L.; Campanini, R.; Capiluppi, P.; Castro, A.; Cavallo, F. R.; Chhibra, S. S.; Codispoti, G.; Cuffiani, M.; Dallavalle, G. M.; Fabbri, F.; Fanfani, A.; Fasanella, D.; Giacomelli, P.; Grandi, C.; Guiducci, L.; Marcellini, S.; Masetti, G.; Montanari, A.; Navarria, F. L.; Perrotta, A.; Rossi, A. M.; Rovelli, T.; Siroli, G. P.; Tosi, N.; Travaglini, R.; Cappello, G.; Chiorboli, M.; Costa, S.; di Mattia, A.; Giordano, F.; Potenza, R.; Tricomi, A.; Tuve, C.; Barbagli, G.; Ciulli, V.; Civinini, C.; D'Alessandro, R.; Focardi, E.; Gori, V.; Lenzi, P.; Meschini, M.; Paoletti, S.; Sguazzoni, G.; Viliani, L.; Benussi, L.; Bianco, S.; Fabbri, F.; Piccolo, D.; Primavera, F.; Calvelli, V.; Ferro, F.; Lo Vetere, M.; Monge, M. R.; Robutti, E.; Tosi, S.; Brianza, L.; Dinardo, M. E.; Fiorendi, S.; Gennai, S.; Gerosa, R.; Ghezzi, A.; Govoni, P.; Malvezzi, S.; Manzoni, R. A.; Marzocchi, B.; Menasce, D.; Moroni, L.; Paganoni, M.; Pedrini, D.; Ragazzi, S.; Redaelli, N.; Tabarelli de Fatis, T.; Buontempo, S.; Cavallo, N.; di Guida, S.; Esposito, M.; Fabozzi, F.; Iorio, A. O. M.; Lanza, G.; Lista, L.; Meola, S.; Merola, M.; Paolucci, P.; Sciacca, C.; Thyssen, F.; Azzi, P.; Bacchetta, N.; Benato, L.; Bisello, D.; Boletti, A.; Carlin, R.; Checchia, P.; Dall'Osso, M.; Dorigo, T.; Dosselli, U.; Gasparini, F.; Gasparini, U.; Gozzelino, A.; Lacaprara, S.; Margoni, M.; Meneguzzo, A. T.; Pazzini, J.; Pegoraro, M.; Pozzobon, N.; Ronchese, P.; Simonetto, F.; Torassa, E.; Tosi, M.; Vanini, S.; Ventura, S.; Zanetti, M.; Zotto, P.; Zucchetta, A.; Zumerle, G.; Braghieri, A.; Magnani, A.; Montagna, P.; Ratti, S. P.; Re, V.; Riccardi, C.; Salvini, P.; Vai, I.; Vitulo, P.; Alunni Solestizi, L.; Bilei, G. M.; Ciangottini, D.; Fanò, L.; Lariccia, P.; Mantovani, G.; Menichelli, M.; Saha, A.; Santocchia, A.; Androsov, K.; Azzurri, P.; Bagliesi, G.; Bernardini, J.; Boccali, T.; Castaldi, R.; Ciocci, M. A.; Dell'Orso, R.; Donato, S.; Fedi, G.; Foà, L.; Giassi, A.; Grippo, M. T.; Ligabue, F.; Lomtadze, T.; Martini, L.; Messineo, A.; Palla, F.; Rizzi, A.; Savoy-Navarro, A.; Serban, A. T.; Spagnolo, P.; Tenchini, R.; Tonelli, G.; Venturi, A.; Verdini, P. G.; Barone, L.; Cavallari, F.; D'Imperio, G.; Del Re, D.; Diemoz, M.; Gelli, S.; Jorda, C.; Longo, E.; Margaroli, F.; Meridiani, P.; Organtini, G.; Paramatti, R.; Preiato, F.; Rahatlou, S.; Rovelli, C.; Santanastasio, F.; Traczyk, P.; Amapane, N.; Arcidiacono, R.; Argiro, S.; Arneodo, M.; Bellan, R.; Biino, C.; Cartiglia, N.; Costa, M.; Covarelli, R.; Degano, A.; Demaria, N.; Finco, L.; Kiani, B.; Mariotti, C.; Maselli, S.; Migliore, E.; Monaco, V.; Monteil, E.; Obertino, M. M.; Pacher, L.; Pastrone, N.; Pelliccioni, M.; Pinna Angioni, G. L.; Ravera, F.; Romero, A.; Ruspa, M.; Sacchi, R.; Solano, A.; Staiano, A.; Belforte, S.; Candelise, V.; Casarsa, M.; Cossutti, F.; Della Ricca, G.; Gobbo, B.; La Licata, C.; Marone, M.; Schizzi, A.; Zanetti, A.; Kropivnitskaya, A.; Nam, S. K.; Kim, D. H.; Kim, G. 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V.; Baskakov, A.; Belyaev, A.; Boos, E.; Demiyanov, A.; Ershov, A.; Gribushin, A.; Kodolova, O.; Korotkikh, V.; Lokhtin, I.; Myagkov, I.; Obraztsov, S.; Petrushanko, S.; Savrin, V.; Snigirev, A.; Vardanyan, I.; Azhgirey, I.; Bayshev, I.; Bitioukov, S.; Kachanov, V.; Kalinin, A.; Konstantinov, D.; Krychkine, V.; Petrov, V.; Ryutin, R.; Sobol, A.; Tourtchanovitch, L.; Troshin, S.; Tyurin, N.; Uzunian, A.; Volkov, A.; Adzic, P.; Cirkovic, P.; Milosevic, J.; Rekovic, V.; Alcaraz Maestre, J.; Calvo, E.; Cerrada, M.; Chamizo Llatas, M.; Colino, N.; de La Cruz, B.; Delgado Peris, A.; Escalante Del Valle, A.; Fernandez Bedoya, C.; Fernández Ramos, J. P.; Flix, J.; Fouz, M. C.; Garcia-Abia, P.; Gonzalez Lopez, O.; Goy Lopez, S.; Hernandez, J. M.; Josa, M. I.; Navarro de Martino, E.; Pérez-Calero Yzquierdo, A.; Puerta Pelayo, J.; Quintario Olmeda, A.; Redondo, I.; Romero, L.; Santaolalla, J.; Soares, M. S.; Albajar, C.; de Trocóniz, J. 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V.; Neugebauer, H.; Orfanelli, S.; Orsini, L.; Pape, L.; Perez, E.; Peruzzi, M.; Petrilli, A.; Petrucciani, G.; Pfeiffer, A.; Pierini, M.; Piparo, D.; Racz, A.; Reis, T.; Rolandi, G.; Rovere, M.; Ruan, M.; Sakulin, H.; Schäfer, C.; Schwick, C.; Seidel, M.; Sharma, A.; Silva, P.; Simon, M.; Sphicas, P.; Steggemann, J.; Stieger, B.; Stoye, M.; Takahashi, Y.; Treille, D.; Triossi, A.; Tsirou, A.; Veres, G. I.; Wardle, N.; Wöhri, H. K.; Zagozdzinska, A.; Zeuner, W. D.; Bertl, W.; Deiters, K.; Erdmann, W.; Horisberger, R.; Ingram, Q.; Kaestli, H. 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M.; Hasegawa, S.; Hirschauer, J.; Hu, Z.; Jayatilaka, B.; Jindariani, S.; Johnson, M.; Joshi, U.; Klima, B.; Kreis, B.; Lammel, S.; Linacre, J.; Lincoln, D.; Lipton, R.; Liu, T.; Lopes de Sá, R.; Lykken, J.; Maeshima, K.; Marraffino, J. M.; Maruyama, S.; Mason, D.; McBride, P.; Merkel, P.; Mrenna, S.; Nahn, S.; Newman-Holmes, C.; O'Dell, V.; Pedro, K.; Prokofyev, O.; Rakness, G.; Sexton-Kennedy, E.; Soha, A.; Spalding, W. J.; Spiegel, L.; Stoynev, S.; Strobbe, N.; Taylor, L.; Tkaczyk, S.; Tran, N. V.; Uplegger, L.; Vaandering, E. W.; Vernieri, C.; Verzocchi, M.; Vidal, R.; Wang, M.; Weber, H. A.; Whitbeck, A.; Acosta, D.; Avery, P.; Bortignon, P.; Bourilkov, D.; Carnes, A.; Carver, M.; Curry, D.; Das, S.; Field, R. D.; Furic, I. K.; Gleyzer, S. 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P.; Haytmyradov, M.; Khristenko, V.; Merlo, J.-P.; Mermerkaya, H.; Mestvirishvili, A.; Moeller, A.; Nachtman, J.; Ogul, H.; Onel, Y.; Ozok, F.; Penzo, A.; Snyder, C.; Tiras, E.; Wetzel, J.; Yi, K.; Anderson, I.; Barnett, B. A.; Blumenfeld, B.; Eminizer, N.; Fehling, D.; Feng, L.; Gritsan, A. V.; Maksimovic, P.; Martin, C.; Osherson, M.; Roskes, J.; Sady, A.; Sarica, U.; Swartz, M.; Xiao, M.; Xin, Y.; You, C.; Baringer, P.; Bean, A.; Benelli, G.; Bruner, C.; Kenny, R. P.; Majumder, D.; Malek, M.; Murray, M.; Sanders, S.; Stringer, R.; Wang, Q.; Ivanov, A.; Kaadze, K.; Khalil, S.; Makouski, M.; Maravin, Y.; Mohammadi, A.; Saini, L. K.; Skhirtladze, N.; Toda, S.; Lange, D.; Rebassoo, F.; Wright, D.; Anelli, C.; Baden, A.; Baron, O.; Belloni, A.; Calvert, B.; Eno, S. C.; Ferraioli, C.; Gomez, J. A.; Hadley, N. J.; Jabeen, S.; Kellogg, R. G.; Kolberg, T.; Kunkle, J.; Lu, Y.; Mignerey, A. C.; Shin, Y. H.; Skuja, A.; Tonjes, M. B.; Tonwar, S. C.; Apyan, A.; Barbieri, R.; Baty, A.; Bierwagen, K.; Brandt, S.; Busza, W.; Cali, I. A.; Demiragli, Z.; Di Matteo, L.; Gomez Ceballos, G.; Goncharov, M.; Gulhan, D.; Iiyama, Y.; Innocenti, G. M.; Klute, M.; Kovalskyi, D.; Lai, Y. S.; Lee, Y.-J.; Levin, A.; Luckey, P. D.; Marini, A. C.; McGinn, C.; Mironov, C.; Narayanan, S.; Niu, X.; Paus, C.; Roland, C.; Roland, G.; Salfeld-Nebgen, J.; Stephans, G. S. F.; Sumorok, K.; Varma, M.; Velicanu, D.; Veverka, J.; Wang, J.; Wang, T. W.; Wyslouch, B.; Yang, M.; Zhukova, V.; Dahmes, B.; Evans, A.; Finkel, A.; Gude, A.; Hansen, P.; Kalafut, S.; Kao, S. C.; Klapoetke, K.; Kubota, Y.; Lesko, Z.; Mans, J.; Nourbakhsh, S.; Ruckstuhl, N.; Rusack, R.; Tambe, N.; Turkewitz, J.; Acosta, J. G.; Oliveros, S.; Avdeeva, E.; Bartek, R.; Bloom, K.; Bose, S.; Claes, D. R.; Dominguez, A.; Fangmeier, C.; Gonzalez Suarez, R.; Kamalieddin, R.; Knowlton, D.; Kravchenko, I.; Meier, F.; Monroy, J.; Ratnikov, F.; Siado, J. E.; Snow, G. R.; Alyari, M.; Dolen, J.; George, J.; Godshalk, A.; Harrington, C.; Iashvili, I.; Kaisen, J.; Kharchilava, A.; Kumar, A.; Rappoccio, S.; Roozbahani, B.; Alverson, G.; Barberis, E.; Baumgartel, D.; Chasco, M.; Hortiangtham, A.; Massironi, A.; Morse, D. M.; Nash, D.; Orimoto, T.; Teixeira de Lima, R.; Trocino, D.; Wang, R.-J.; Wood, D.; Zhang, J.; Bhattacharya, S.; Hahn, K. A.; Kubik, A.; Low, J. F.; Mucia, N.; Odell, N.; Pollack, B.; Schmitt, M.; Sung, K.; Trovato, M.; Velasco, M.; Brinkerhoff, A.; Dev, N.; Hildreth, M.; Jessop, C.; Karmgard, D. J.; Kellams, N.; Lannon, K.; Marinelli, N.; Meng, F.; Mueller, C.; Musienko, Y.; Planer, M.; Reinsvold, A.; Ruchti, R.; Smith, G.; Taroni, S.; Valls, N.; Wayne, M.; Wolf, M.; Woodard, A.; Antonelli, L.; Brinson, J.; Bylsma, B.; Durkin, L. S.; Flowers, S.; Hart, A.; Hill, C.; Hughes, R.; Ji, W.; Ling, T. Y.; Liu, B.; Luo, W.; Puigh, D.; Rodenburg, M.; Winer, B. L.; Wulsin, H. W.; Driga, O.; Elmer, P.; Hardenbrook, J.; Hebda, P.; Koay, S. A.; Lujan, P.; Marlow, D.; Medvedeva, T.; Mooney, M.; Olsen, J.; Palmer, C.; Piroué, P.; Stickland, D.; Tully, C.; Zuranski, A.; Malik, S.; Barker, A.; Barnes, V. E.; Benedetti, D.; Bortoletto, D.; Gutay, L.; Jha, M. K.; Jones, M.; Jung, A. W.; Jung, K.; Kumar, A.; Miller, D. H.; Neumeister, N.; Radburn-Smith, B. C.; Shi, X.; Shipsey, I.; Silvers, D.; Sun, J.; Svyatkovskiy, A.; Wang, F.; Xie, W.; Xu, L.; Parashar, N.; Stupak, J.; Adair, A.; Akgun, B.; Chen, Z.; Ecklund, K. M.; Geurts, F. J. M.; Guilbaud, M.; Li, W.; Michlin, B.; Northup, M.; Padley, B. P.; Redjimi, R.; Roberts, J.; Rorie, J.; Tu, Z.; Zabel, J.; Betchart, B.; Bodek, A.; de Barbaro, P.; Demina, R.; Eshaq, Y.; Ferbel, T.; Galanti, M.; Garcia-Bellido, A.; Han, J.; Harel, A.; Hindrichs, O.; Khukhunaishvili, A.; Lo, K. H.; Petrillo, G.; Tan, P.; Verzetti, M.; Chou, J. P.; Contreras-Campana, E.; Ferencek, D.; Gershtein, Y.; Halkiadakis, E.; Hidas, D.; Hughes, E.; Kaplan, S.; Kunnawalkam Elayavalli, R.; Lath, A.; Nash, K.; Saka, H.; Salur, S.; Schnetzer, S.; Sheffield, D.; Somalwar, S.; Stone, R.; Thomas, S.; Thomassen, P.; Walker, M.; Foerster, M.; Riley, G.; Rose, K.; Spanier, S.; Bouhali, O.; Castaneda Hernandez, A.; Celik, A.; Dalchenko, M.; de Mattia, M.; Delgado, A.; Dildick, S.; Eusebi, R.; Gilmore, J.; Huang, T.; Kamon, T.; Krutelyov, V.; Mueller, R.; Osipenkov, I.; Pakhotin, Y.; Patel, R.; Perloff, A.; Rose, A.; Safonov, A.; Tatarinov, A.; Ulmer, K. A.; Akchurin, N.; Cowden, C.; Damgov, J.; Dragoiu, C.; Dudero, P. R.; Faulkner, J.; Kunori, S.; Lamichhane, K.; Lee, S. W.; Libeiro, T.; Undleeb, S.; Volobouev, I.; Appelt, E.; Delannoy, A. G.; Greene, S.; Gurrola, A.; Janjam, R.; Johns, W.; Maguire, C.; Mao, Y.; Melo, A.; Ni, H.; Sheldon, P.; Tuo, S.; Velkovska, J.; Xu, Q.; Arenton, M. W.; Cox, B.; Francis, B.; Goodell, J.; Hirosky, R.; Ledovskoy, A.; Li, H.; Lin, C.; Neu, C.; Sinthuprasith, T.; Sun, X.; Wang, Y.; Wolfe, E.; Wood, J.; Xia, F.; Clarke, C.; Harr, R.; Karchin, P. E.; Kottachchi Kankanamge Don, C.; Lamichhane, P.; Sturdy, J.; Belknap, D. A.; Carlsmith, D.; Cepeda, M.; Dasu, S.; Dodd, L.; Duric, S.; Gomber, B.; Grothe, M.; Hall-Wilton, R.; Herndon, M.; Hervé, A.; Klabbers, P.; Lanaro, A.; Levine, A.; Long, K.; Loveless, R.; Mohapatra, A.; Ojalvo, I.; Perry, T.; Pierro, G. A.; Polese, G.; Ruggles, T.; Sarangi, T.; Savin, A.; Sharma, A.; Smith, N.; Smith, W. H.; Taylor, D.; Verwilligen, P.; Woods, N.

    2016-02-01

    The quark-gluon plasma is studied via medium-induced changes to correlations between jets and charged particles in PbPb collisions compared to pp reference data. This analysis uses data sets from PbPb and pp collisions with integrated luminosities of 166 μb-1 and 5.3 pb-1, respectively, collected at √{s_{NN}}=2.76; TeV. The angular distributions of charged particles are studied as a function of relative pseudorapidity (Δ η) and relative azimuthal angle (Δ ϕ) with respect to reconstructed jet directions. Charged particles are correlated with all jets with transverse momentum ( p T) above 120 GeV, and with the leading and subleading jets (the highest and second-highest in p T, respectively) in a selection of back-to-back dijet events. Modifications in PbPb data relative to pp reference data are characterized as a function of PbPb collision centrality and charged particle p T. A centrality-dependent excess of low- p T particles is present for all jets studied, and is most pronounced in the most central events. This excess of low- p T particles follows a Gaussian-like distribution around the jet axis, and extends to large relative angles of Δ η ≈ 1 and Δ ϕ ≈ 1. [Figure not available: see fulltext.

  10. Correlations between jets and charged particles in PbPb and pp collisions at $$ \\sqrt{s_{\\mathrm{NN}}}=2.76 $$ TeV

    DOE PAGES

    Khachatryan, Vardan

    2016-02-23

    In this study, the quark-gluon plasma is studied via medium-induced changes to correlations between jets and charged particles in PbPb collisions compared to pp reference data. This analysis uses data sets from PbPb and pp collisions with integrated luminosities of 166 inverse microbarns and 5.3 inverse picobarns, respectively, collected atmore » $$ \\sqrt{s_{\\mathrm{NN}}}=2.76 $$ TeV. The angular distributions of charged particles are studied as a function of relative pseudorapidity (Δη) and relative azimuthal angle (ΔΦ) with respect to reconstructed jet directions. Charged particles are correlated with all jets with transverse momentum (p T) above 120 GeV, and with the leading and subleading jets (the highest and second-highest in p T, respectively) in a selection of back-to-back dijet events. Modifications in PbPb data relative to pp reference data are characterized as a function of PbPb collision centrality and charged particle p T. A centrality-dependent excess of low-p T particles is present for all jets studied, and is most pronounced in the most central events. This excess of low-p T particles follows a Gaussian-like distribution around the jet axis, and extends to large relative angles of Δη ≈ 1 and ΔΦ ≈ 1.« less

  11. Modulating the line shape of magnetoconductance by varying the charge injection in polymer light-emitting diodes

    NASA Astrophysics Data System (ADS)

    Chitraningrum, Nidya; Chu, Ting-Yi; Huang, Ping-Tsung; Wen, Ten-Chin; Guo, Tzung-Fang

    2018-02-01

    We fabricate the phenyl-substituted poly(p-phenylene vinylene) copolymer (super yellow, SY-PPV)-based polymer light-emitting diodes (PLEDs) with different device architectures to modulate the injection of opposite charge carriers and investigate the corresponding magnetoconductance (MC) responses. At the first glance, we find that all PLEDs exhibit the positive MC responses. By applying the mathematical analysis to fit the curves with two empirical equations of a non-Lorentzian and a Lorentzian function, we are able to extract the hidden negative MC component from the positive MC curve. We attribute the growth of the negative MC component to the reduced interaction of the triplet excitons with charges to generate the free charge carriers as modulated by the applied magnetic field, known as the triplet exciton-charge reaction, by analyzing MC responses for PLEDs of the charge-unbalanced and hole-blocking device configurations. The negative MC component causes the broadening of the line shape in MC curves.

  12. 20 CFR 404.435 - Excess earnings; months to which excess earnings can or cannot be charged; grace year defined.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... her. Example 1: Don, age 62, will retire from his regular job in April of next year. Although he will... month of your taxable year until you show to our satisfaction that in a particular month you did not... annual net income or loss (see § 404.429). (e) Presumption regarding services for wages. You are presumed...

  13. 40 CFR 60.755 - Compliance provisions.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ....753(b). If negative pressure cannot be achieved without excess air infiltration within 15 calendar... after gas collection system startup. (5) For the purpose of identifying whether excess air infiltration...

  14. Developing a charging system for a nursing specialty: ET nursing.

    PubMed

    Lowery, G E; Gage, J; Lowenstein, A

    1994-05-01

    Because of limited resources and economic constraints, justifying the existence of ET nurses has become an economic challenge for hospitals and nurses. To justify the role of the ET nurse, a charging system for enterostomal therapy was developed at a corporate, for-profit hospital. Three months after implementation, an evaluation of the system demonstrated that revenue was generated in excess of the ET nurse's salary.

  15. Evidence for an Excess of B̄→D (*)τ⁻ν̄ τ Decays

    DOE PAGES

    Lees, J. P.; Poireau, V.; Tisserand, V.; ...

    2012-09-06

    Based on the full BABAR data sample, we report improved measurements of the ratios R(D (*))=B(B̄→D (*)τ⁻ν¯ τ)/B(B̄→D (*)l l¯ν¯ l), where l is either e or μ. These ratios are sensitive to new physics contributions in the form of a charged Higgs boson. We measure R(D)=0.440±0.058±0.042 and R(D*)=0.332±0.024±0.018, which exceed the standard model expectations by 2.0σ and 2.7σ, respectively. Taken together, our results disagree with these expectations at the 3.4σ level. This excess cannot be explained by a charged Higgs boson in the type II two-Higgs-doublet model.

  16. Negative charge emission due to excimer laser bombardment of sodium trisilicate glass

    NASA Astrophysics Data System (ADS)

    Langford, S. C.; Jensen, L. C.; Dickinson, J. T.; Pederson, L. R.

    1990-10-01

    We describe measurements of negative charge emission accompanying irradiation of sodium trisilicate glass (Na2Oṡ3SiO2) with 248-nm excimer laser light at fluences on the order of 2 J/cm2 per pulse, i.e., at the threshold for ablative etching of the glass surface. The negative charge emission consists of a very prompt photoelectron burst coincident with the laser pulse, followed by a much slower plume of electrons and negative ions traveling with a high density cloud of positive ions, previously identified as primarily Na+. Using combinations of E and B fields in conjunction with time-of-flight methods, the negative ions were successfully separated from the plume and tentatively identified as O-, Si-, NaO-, and perhaps NaSi-. These negative species are probably formed by gas phase collisions in the near-surface region which result in electron attachment.

  17. Negatively Charged Lipid Membranes Promote a Disorder-Order Transition in the Yersinia YscU Protein

    PubMed Central

    Weise, Christoph F.; Login, Frédéric H.; Ho, Oanh; Gröbner, Gerhard; Wolf-Watz, Hans; Wolf-Watz, Magnus

    2014-01-01

    The inner membrane of Gram-negative bacteria is negatively charged, rendering positively charged cytoplasmic proteins in close proximity likely candidates for protein-membrane interactions. YscU is a Yersinia pseudotuberculosis type III secretion system protein crucial for bacterial pathogenesis. The protein contains a highly conserved positively charged linker sequence that separates membrane-spanning and cytoplasmic (YscUC) domains. Although disordered in solution, inspection of the primary sequence of the linker reveals that positively charged residues are separated with a typical helical periodicity. Here, we demonstrate that the linker sequence of YscU undergoes a largely electrostatically driven coil-to-helix transition upon binding to negatively charged membrane interfaces. Using membrane-mimicking sodium dodecyl sulfate micelles, an NMR derived structural model reveals the induction of three helical segments in the linker. The overall linker placement in sodium dodecyl sulfate micelles was identified by NMR experiments including paramagnetic relaxation enhancements. Partitioning of individual residues agrees with their hydrophobicity and supports an interfacial positioning of the helices. Replacement of positively charged linker residues with alanine resulted in YscUC variants displaying attenuated membrane-binding affinities, suggesting that the membrane interaction depends on positive charges within the linker. In vivo experiments with bacteria expressing these YscU replacements resulted in phenotypes displaying significantly reduced effector protein secretion levels. Taken together, our data identify a previously unknown membrane-interacting surface of YscUC that, when perturbed by mutations, disrupts the function of the pathogenic machinery in Yersinia. PMID:25418176

  18. Negatively charged lipid membranes promote a disorder-order transition in the Yersinia YscU protein.

    PubMed

    Weise, Christoph F; Login, Frédéric H; Ho, Oanh; Gröbner, Gerhard; Wolf-Watz, Hans; Wolf-Watz, Magnus

    2014-10-21

    The inner membrane of Gram-negative bacteria is negatively charged, rendering positively charged cytoplasmic proteins in close proximity likely candidates for protein-membrane interactions. YscU is a Yersinia pseudotuberculosis type III secretion system protein crucial for bacterial pathogenesis. The protein contains a highly conserved positively charged linker sequence that separates membrane-spanning and cytoplasmic (YscUC) domains. Although disordered in solution, inspection of the primary sequence of the linker reveals that positively charged residues are separated with a typical helical periodicity. Here, we demonstrate that the linker sequence of YscU undergoes a largely electrostatically driven coil-to-helix transition upon binding to negatively charged membrane interfaces. Using membrane-mimicking sodium dodecyl sulfate micelles, an NMR derived structural model reveals the induction of three helical segments in the linker. The overall linker placement in sodium dodecyl sulfate micelles was identified by NMR experiments including paramagnetic relaxation enhancements. Partitioning of individual residues agrees with their hydrophobicity and supports an interfacial positioning of the helices. Replacement of positively charged linker residues with alanine resulted in YscUC variants displaying attenuated membrane-binding affinities, suggesting that the membrane interaction depends on positive charges within the linker. In vivo experiments with bacteria expressing these YscU replacements resulted in phenotypes displaying significantly reduced effector protein secretion levels. Taken together, our data identify a previously unknown membrane-interacting surface of YscUC that, when perturbed by mutations, disrupts the function of the pathogenic machinery in Yersinia.

  19. Low-energy electron interaction with retusin extracted from Maackia amurensis: towards a molecular mechanism of the biological activity of flavonoids.

    PubMed

    Pshenichnyuk, Stanislav A; Elkin, Yury N; Kulesh, Nadezda I; Lazneva, Eleonora F; Komolov, Alexei S

    2015-07-14

    The antioxidant isoflavone retusin efficiently attaches low-energy electrons in vacuo, generating fragment species via dissociative electron attachment (DEA), as has been shown by DEA spectroscopy. According to in silico results obtained by means of density functional theory, retusin is able to attach solvated electrons and could be decomposed under reductive conditions in vivo, for instance, near the mitochondrial electron transport chain, analogous to gas-phase DEA. The most intense decay channels of retusin temporary negative ions were found to be associated with the elimination of H atoms and H2 molecules. Doubly dehydrogenated fragment anions were predicted to possess a quinone structure. It is thought that molecular hydrogen, known for its selective antioxidant properties, can be efficiently generated via electron attachment to retusin in mitochondria and may be responsible for its antioxidant activity. The second abundant species, i.e., quinone bearing an excess negative charge, can serve as an electron carrier and can return the captured electron back to the respiration cycle. The number of OH substituents and their relative positions are crucial for the present molecular mechanism, which can explain the radical scavenging activity of polyphenolic compounds.

  20. Interactions and encapsulation of vitamins C, B3, and B6 with dendrimers in water.

    PubMed

    Boisselier, Elodie; Liang, Liyuan; Dalko-Csiba, Maria; Ruiz, Jaime; Astruc, Didier

    2010-05-25

    Titrations of commercial diaminobutane (DAB) and polyamidoamine (PAMAM) dendrimers by vitamins C (ascorbic acid, AA), B(3) (nicotinic acid), and B(6) (pyridoxine) were monitored by (1)H NMR spectroscopy using the chemical shifts of both dendrimer and vitamin protons and analyzed by comparison with the titration of propylamine. Quaternarizations of the terminal primary amino groups and intradendritic tertiary amino groups, which are nearly quantitative with vitamin C, were characterized by more or less sharp variations (Deltadelta) of the (1)H chemical shift (delta) at the equivalence points. The peripheral primary amino groups of the DAB dendrimers were quaternarized first, but not selectively, whereas a sharp chemical-shift variation was recorded for the inner methylene protons near the tertiary amines, thereby indicating encapsulation, when all the dendritic amines were quaternarized. With DAB-G5-64-NH(2), some excess acid is required to protonate the inner amino groups, presumably because of basicity decrease due to excess charge repulsion. On the other hand, this selectivity was not observed with PAMAM dendrimers. The special case of the titration of the dendrimers by vitamin B(6) indicates only dominant supramolecular hydrogen-bonding interactions and no quaternarization, with core amino groups being privileged, which indicates the strong tendency to encapsulate vitamins. With vitamin B(3), a carboxylic acid, titration of DAB-G3-16-NH(2) shows that only six peripheral amino groups are protonated on average, even with excess vitamin B(3), because protonation is all the more difficult due to increased charge repulsion, as positive charges accumulate around the dendrimer. Inner amino groups interact with this vitamin, however, thus indicating encapsulation presumably with supramolecular hydrogen bonding without much charge transfer.

  1. Spacecraft Electrostatic Radiation Shielding

    NASA Technical Reports Server (NTRS)

    2008-01-01

    This project analyzed the feasibility of placing an electrostatic field around a spacecraft to provide a shield against radiation. The concept was originally proposed in the 1960s and tested on a spacecraft by the Soviet Union in the 1970s. Such tests and analyses showed that this concept is not only feasible but operational. The problem though is that most of this work was aimed at protection from 10- to 100-MeV radiation. We now appreciate that the real problem is 1- to 2-GeV radiation. So, the question is one of scaling, in both energy and size. Can electrostatic shielding be made to work at these high energy levels and can it protect an entire vehicle? After significant analysis and consideration, an electrostatic shield configuration was proposed. The selected architecture was a torus, charged to a high negative voltage, surrounding the vehicle, and a set of positively charged spheres. Van de Graaff generators were proposed as the mechanism to move charge from the vehicle to the torus to generate the fields necessary to protect the spacecraft. This design minimized complexity, residual charge, and structural forces and resolved several concerns raised during the internal critical review. But, it still is not clear if such a system is costeffective or feasible, even though several studies have indicated usefulness for radiation protection at energies lower than that of the galactic cosmic rays. Constructing such a system will require power supplies that can generate voltages 10 times that of the state of the art. Of more concern is the difficulty of maintaining the proper net charge on the entire structure and ensuring that its interaction with solar wind will not cause rapid discharge. Yet, if these concerns can be resolved, such a scheme may provide significant radiation shielding to future vehicles, without the excessive weight or complexity of other active shielding techniques.

  2. What Is Known About the Correlates and Impact of Excess Skin After Bariatric Surgery: a Scoping Review.

    PubMed

    Baillot, Aurélie; Brais-Dussault, Elsa; Bastin, Anne; Cyr, Caroline; Brunet, Jennifer; Aimé, Annie; Romain, Ahmed J; Langlois, Marie-France; Bouchard, Stéphane; Tchernof, André; Rabasa-Lhoret, Rémi; Garneau, Pierre-Yves; Bernard, Paquito

    2017-09-01

    Although bariatric surgery (BS) improves health among adults with severe obesity, it results in excess skin in more than 70% of adults. The purpose of this study was to synthesize current knowledge on (1) the impact of excess skin experienced by adults after BS and (2) the correlates of excess skin quantity and inconveniences. PubMed, PsyArticles, and CINAHL databases were searched in May 2016 for relevant studies. Titles, abstracts, and full texts of studies retrieved were screened independently by two reviewers against inclusion criteria: (1) peer-reviewed primary research studies, (2) samples with adults who underwent BS, and (3) studies reporting the impact of excess skin and/or excess skin correlates. Thirteen quantitative and eleven qualitative studies met inclusion criteria. Negative physical, psychosocial, and daily life impacts of excess skin were reported in 67, 75, and 83% of studies, respectively. Women reported more excess skin and greater inconveniences of excess skin than did men. Based on the quantitative studies, pre-BS BMI, time since BS, and type of BS were not significantly associated with inconveniences of excess skin; findings were inconclusive for other correlates found (e.g. age, weight loss, BMI). Excess skin may adversely impact adults' physical and psychosocial functioning, as well as their activities of daily life after BS. However, evidence is lacking to determine which adults may be at heightened risk of developing or being negatively impacted by excess skin. More research on correlates of excess skill is needed to inform the development of tailored interventions in those more vulnerable to developing excess skin after BS to mitigate adverse consequences.

  3. [Excessive computer usage in adolescents--results of a psychometric evaluation].

    PubMed

    Grüsser, Sabine M; Thalemann, Ralf; Albrecht, Ulrike; Thalemann, Carolin N

    2005-03-01

    Excessive computer and video game playing among children is being critically discussed from a pedagogic and public health point of view. To date, no reliable data for this phenomenon in Germany exists. In the present study, the excessive usage of computer and video games is seen as a rewarding behavior which can, due to learning mechanisms, become a prominent and inadequate strategy for children to cope with negative emotions like frustration, uneasiness and fears. In the survey, 323 children ranging in age from 11 to 14 years were asked about their video game playing behavior. Criteria for excessive computer and video game playing were developed in accordance with the criteria for dependency and pathological gambling (DSM-IV, ICD-10). Data show that 9.3% (N = 30) of the children fulfill all criteria for excessive computer and video game playing. Furthermore, these children differ from their class mates with respect to watching television, communication patterns, the ability to concentrate in school lectures and the preferred strategies coping with negative emotions. In accordance with findings in studies about substance-related addiction, data suggest that excessive computer and video game players use their excessive rewarding behavior specifically as an inadequate stress coping strategy.

  4. Protein Charge and Mass Contribute to the Spatio-temporal Dynamics of Protein-Protein Interactions in a Minimal Proteome

    PubMed Central

    Xu, Yu; Wang, Hong; Nussinov, Ruth; Ma, Buyong

    2013-01-01

    We constructed and simulated a ‘minimal proteome’ model using Langevin dynamics. It contains 206 essential protein types which were compiled from the literature. For comparison, we generated six proteomes with randomized concentrations. We found that the net charges and molecular weights of the proteins in the minimal genome are not random. The net charge of a protein decreases linearly with molecular weight, with small proteins being mostly positively charged and large proteins negatively charged. The protein copy numbers in the minimal genome have the tendency to maximize the number of protein-protein interactions in the network. Negatively charged proteins which tend to have larger sizes can provide large collision cross-section allowing them to interact with other proteins; on the other hand, the smaller positively charged proteins could have higher diffusion speed and are more likely to collide with other proteins. Proteomes with random charge/mass populations form less stable clusters than those with experimental protein copy numbers. Our study suggests that ‘proper’ populations of negatively and positively charged proteins are important for maintaining a protein-protein interaction network in a proteome. It is interesting to note that the minimal genome model based on the charge and mass of E. Coli may have a larger protein-protein interaction network than that based on the lower organism M. pneumoniae. PMID:23420643

  5. An analytic expression for the sheath criterion in magnetized plasmas with multi-charged ion species

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Hatami, M. M., E-mail: m-hatami@kntu.ac.ir

    2015-04-15

    The generalized Bohm criterion in magnetized multi-component plasmas consisting of multi-charged positive and negative ion species and electrons is analytically investigated by using the hydrodynamic model. It is assumed that the electrons and negative ion density distributions are the Boltzmann distribution with different temperatures and the positive ions enter into the sheath region obliquely. Our results show that the positive and negative ion temperatures, the orientation of the applied magnetic field and the charge number of positive and negative ions strongly affect the Bohm criterion in these multi-component plasmas. To determine the validity of our derived generalized Bohm criterion, itmore » reduced to some familiar physical condition and it is shown that monotonically reduction of the positive ion density distribution leading to the sheath formation occurs only when entrance velocity of ion into the sheath satisfies the obtained Bohm criterion. Also, as a practical application of the obtained Bohm criterion, effects of the ionic temperature and concentration as well as magnetic field on the behavior of the charged particle density distributions and so the sheath thickness of a magnetized plasma consisting of electrons and singly charged positive and negative ion species are studied numerically.« less

  6. Determination of gas phase protein ion densities via ion mobility analysis with charge reduction.

    PubMed

    Maisser, Anne; Premnath, Vinay; Ghosh, Abhimanyu; Nguyen, Tuan Anh; Attoui, Michel; Hogan, Christopher J

    2011-12-28

    We use a charge reduction electrospray (ESI) source and subsequent ion mobility analysis with a differential mobility analyzer (DMA, with detection via both a Faraday cage electrometer and a condensation particle counter) to infer the densities of single and multiprotein ions of cytochrome C, lysozyme, myoglobin, ovalbumin, and bovine serum albumin produced from non-denaturing (20 mM aqueous ammonium acetate) and denaturing (1 : 49.5 : 49.5, formic acid : methanol : water) ESI. Charge reduction is achieved through use of a Po-210 radioactive source, which generates roughly equal concentrations of positive and negative ions. Ions produced by the source collide with and reduce the charge on ESI generated drops, preventing Coulombic fissions, and unlike typical protein ESI, leading to gas-phase protein ions with +1 to +3 excess charges. Therefore, charge reduction serves to effectively mitigate any role that Coulombic stretching may play on the structure of the gas phase ions. Density inference is made via determination of the mobility diameter, and correspondingly the spherical equivalent protein volume. Through this approach it is found that for both non-denaturing and denaturing ESI-generated ions, gas-phase protein ions are relatively compact, with average densities of 0.97 g cm(-3) and 0.86 g cm(-3), respectively. Ions from non-denaturing ESI are found to be slightly more compact than predicted from the protein crystal structures, suggesting that low charge state protein ions in the gas phase are slightly denser than their solution conformations. While a slight difference is detected between the ions produced with non-denaturing and denaturing ESI, the denatured ions are found to be much more dense than those examined previously by drift tube mobility analysis, in which charge reduction was not employed. This indicates that Coulombic stretching is typically what leads to non-compact ions in the gas-phase, and suggests that for gas phase measurements to be correlated to biomolecular structures in solution, low charge state ions should be analyzed. Further, to determine if different solution conditions give rise to ions of different structure, ions of similar charge state should be compared. Non-denatured protein ion densities are found to be in excellent agreement with non-denatured protein ion densities inferred from prior DMA and drift tube measurements made without charge reduction (all ions with densities in the 0.85-1.10 g cm(-3) range), showing that these ions are not strongly influenced by Coulombic stretching nor by analysis method.

  7. Inkjet Deposition of Layer by Layer Assembled Films

    PubMed Central

    Andres, Christine M.; Kotov, Nicholas A.

    2010-01-01

    Layer-by-layer assembly (LBL) can create advanced composites with exceptional properties unavailable by other means, but the laborious deposition process and multiple dipping cycles hamper their utilization in microtechnologies and electronics. Multiple rinse steps provide both structural control and thermodynamic stability to LBL multilayers but they significantly limit their practical applications and contribute significantly to the processing time and waste. Here we demonstrate that by employing inkjet technology one can deliver the necessary quantities of LBL components required for film build-up without excess, eliminating the need for repetitive rinsing steps. This feature differentiates this approach from all other recognized LBL modalities. Using a model system of negatively charged gold nanoparticles and positively charged poly(diallyldimethylammonium) chloride, the material stability, nanoscale control over thickness and particle coverage offered by the inkjet LBL technique are shown to be equal or better than the multilayers made with traditional dipping cycles. The opportunity for fast deposition of complex metallic patterns using a simple inkjet printer was also shown. The additive nature of LBL deposition based on the formation of insoluble nanoparticle-polyelectrolyte complexes of various compositions provides an excellent opportunity for versatile, multi-component, and non-contact patterning for the simple production of stratified patterns that are much needed in advanced devices. PMID:20863114

  8. Comparing the effects of negative and mixed emotional messages on predicted occasional excessive drinking.

    PubMed

    Carrera, Pilar; Caballero, Amparo; Muñoz, Dolores

    2008-01-01

    In this work we present two types of emotional message, negative (sadness) versus mixed (joy and sadness), with the aim of studying their differential effect on attitude change and the probability estimated by participants of repeating the behavior of occasional excessive drinking in the near future. The results show that for the group of participants with moderate experience in this behavior the negative message, compared to the mixed one, is associated with higher probability of repeating the risk behavior and a less negative attitude toward it. These results suggest that mixed emotional messages (e.g. joy and sadness messages) could be more effective in campaigns for the prevention of this risk behavior.

  9. Hybrid power systems for autonomous MEMS

    NASA Astrophysics Data System (ADS)

    Bennett, Daniel M.; Selfridge, Richard H.; Humble, Paul; Harb, John N.

    2001-08-01

    This paper describes the design of a hybrid power system for use with autonomous MEMS and other microdevices. This hybrid power system includes energy conversion and storage along with an electronic system for managing the collection and distribution of power. It offers flexibility and longevity in a compact package. The hybrid power system couples a silicon solar cell with a microbattery specially designed for MEMS applications. We have designed a control/interface charging circuit to be compatible with a MEMS duty cycle. The design permits short pulses of 'high' power while taking care to avoid excessive charging or discharging of the battery. Charging is carefully controlled to provide a balance between acceptably small charging times and a charging profile that extends battery life. Our report describes the charging of our Ni/Zn microbatteries using solar cells. To date we have demonstrated thousands of charge/discharge cycles of a simulated MEMS duty cycle.

  10. Fractionation and characterization of natural organic matter from certain rivers and soils by free-flow electrophoresis

    USGS Publications Warehouse

    Leenheer, J.A.; Malcolm, R.L.

    1973-01-01

    Soluble river organic matter and soil fulvic acids from a variety of environments were compared by examining the free-flow electrophoretic fractionation curves of organic carbon, color, and polysaccharides. Significant amounts of virtually colorless organic material were found in both the soil and the river preparations. Polysaccharides comprised 20-75 percent of the colorless material in the soil fulvic acids but only 3.2-7.0 percent of the colorless material in the river preparations. A significant amount of polysaccharides was complexed with organic materials having negative charges. Amounts of polysaccharides were greater in the Fairbanks soil from Alaska than in the soils from North Carolina or Iowa, and they were greater in the Tahquamenon River in Michigan than in the two rivers in Florida; this suggests that polysaccharide degradation is slower in cooler environments. For all of the organic preparations which were fractionated, the intensity of the yellow color increased as the charge on the organic anion increased. Highly colored, negatively charged organic material was found to be present in greater amounts in the subsurface spodic soil horizon of the Lakewood and Fairbanks soils than in the surface mollic horizon of the Macksburg soil. Infrared spectroscopy and elemental analysis of four pooled fractions of the Fairbanks fulvic acid indicated increasing aromatic character with increasing negative charge. An increase in the carboxyl content with negative charge suggests the carboxyl group as the primary source of the negative charge.

  11. Cationic cell-penetrating peptide binds to planar lipid bilayers containing negatively charged lipids but does not induce conductive pores.

    PubMed

    Gurnev, Philip A; Yang, Sung-Tae; Melikov, Kamran C; Chernomordik, Leonid V; Bezrukov, Sergey M

    2013-05-07

    Using a cation-selective gramicidin A channel as a sensor of the membrane surface charge, we studied interactions of oligoarginine peptide R9C, a prototype cationic cell-penetrating peptide (CPP), with planar lipid membranes. We have found that R9C sorption to the membrane depends strongly on its lipid composition from virtually nonexistent for membranes made of uncharged lipids to very pronounced for membranes containing negatively charged lipids, with charge overcompensation at R9C concentrations exceeding 1 μM. The sorption was reversible as it was removed by addition of polyanionic dextran sulfate to the membrane bathing solution. No membrane poration activity of R9C (as would be manifested by increased bilayer conductance) was detected in the charged or neutral membranes, including those with asymmetric negative/neutral and negative/positive lipid leaflets. We conclude that interaction of R9C with planar lipid bilayers does not involve pore formation in all studied lipid combinations up to 20 μM peptide concentration. However, R9C induces leakage of negatively charged but not neutral liposomes in a process that involves lipid mixing between liposomes. Our findings suggest that direct traversing of CPPs through the uncharged outer leaflet of the plasma membrane bilayer is unlikely and that permeabilization necessarily involves both anionic lipids and CPP-dependent fusion between opposing membranes. Copyright © 2013 Biophysical Society. Published by Elsevier Inc. All rights reserved.

  12. The secondary supernova machine: Gravitational compression, stored Coulomb energy, and SNII displays

    NASA Astrophysics Data System (ADS)

    Clayton, Donald D.; Meyer, Bradley S.

    2016-04-01

    Radioactive power for several delayed optical displays of core-collapse supernovae is commonly described as having been provided by decays of 56Ni nuclei. This review analyses the provenance of that energy more deeply: the form in which that energy is stored; what mechanical work causes its storage; what conservation laws demand that it be stored; and why its release is fortuitously delayed for about 106 s into a greatly expanded supernova envelope. We call the unifying picture of those energy transfers the secondary supernova machine owing to its machine-like properties; namely, mechanical work forces storage of large increases of nuclear Coulomb energy, a positive energy component within new nuclei synthesized by the secondary machine. That positive-energy increase occurs despite the fusion decreasing negative total energy within nuclei. The excess of the Coulomb energy can later be radiated, accounting for the intense radioactivity in supernovae. Detailed familiarity with this machine is the focus of this review. The stored positive-energy component created by the machine will not be reduced until roughly 106 s later by radioactive emissions (EC and β +) owing to the slowness of weak decays. The delayed energy provided by the secondary supernova machine is a few × 1049 erg, much smaller than the one percent of the 1053 erg collapse that causes the prompt ejection of matter; however, that relatively small stored energy is vital for activation of the late displays. The conceptual basis of the secondary supernova machine provides a new framework for understanding the energy source for late SNII displays. We demonstrate the nuclear dynamics with nuclear network abundance calculations, with a model of sudden compression and reexpansion of the nuclear gas, and with nuclear energy decompositions of a nuclear-mass law. These tools identify excess Coulomb energy, a positive-energy component of the total negative nuclear energy, as the late activation energy. If the value of fundamental charge e were smaller, SNII would not be so profoundly radioactive. Excess Coulomb energy has been carried within nuclei radially for roughly 109 km before being radiated into greatly expanded supernova remnants. The Coulomb force claims heretofore unacknowledged significance for supernova physics.

  13. Costs Associated with Anesthesia-Related Adverse Events During Labor and Delivery in New York State, 2010.

    PubMed

    Hunt, Tristan D; Guglielminotti, Jean; Li, Guohua

    2016-06-01

    The safety of anesthetic care provided during childbirth has improved during the past 2 decades in the United States, with a marked decrease in the rate of anesthesia-related adverse events (ARAEs). To date, there is little research on the costs of ARAEs in obstetrics. This study aims to assess the excess cost and cost per admission associated with ARAEs during labor and delivery. Data came from the New York State Inpatient Database 2010. Discharge records indicating labor and delivery and ARAEs were identified with International Classification of Diseases, Ninth Revision, Clinical Modification codes. ARAEs were defined as minor if not associated with maternal death, cardiac arrest, or severe morbidity. Costs were calculated as the product of hospital charges and the group average all-payer inpatient charge-to-cost conversion ratio. Excess cost was calculated as the difference between the mean cost of discharges with and without ARAEs. The cost per admission was calculated as the product of the excess cost and ARAE incidence. Excess costs and cost per admission were also calculated for 2 pregnancy-related complications: postpartum hemorrhage and preeclampsia/eclampsia. There were 228,104 delivery-related discharges in the study; of these, 1053 recorded at least 1 ARAE (4.6 per 1000), with 1034 (98.2%) of the ARAEs being minor. The adjusted excess cost associated with ARAEs was $1189 (95% confidence interval [CI], 1033-1350) and the cost per admission $5.49 (95% CI, 4.77-6.23). The incidence of postpartum hemorrhage and preeclamspia/eclampsia was 25.1 and 43.8 per 1000, respectively. The adjusted excess cost was $679 (95% CI, 608-748) and $1328 (95% CI, 1272-1378), respectively; the cost per admission was $17.07 (95% CI, 15.27-18.81) and $58.16 (95% CI, 55.72-60.34), respectively. ARAEs during labor and delivery are associated with significant excess cost. However, the excess cost per admission for ARAEs is significantly less compared with the excess cost per admission for preeclampsia/eclampsia and postpartum hemorrhage.

  14. Non-conservation of global charges in the Brane Universe and baryogenesis

    NASA Astrophysics Data System (ADS)

    Dvali, Gia; Gabadadze, Gregory

    1999-08-01

    We argue that global charges, such as baryon or lepton number, are not conserved in theories with the Standard Model fields localized on the brane which propagates in higher-dimensional space-time. The global-charge non-conservation is due to quantum fluctuations of the brane surface. These fluctuations create ``baby branes'' that can capture some global charges and carry them away into the bulk of higher-dimensional space. Such processes are exponentially suppressed at low-energies, but can be significant at high enough temperatures or energies. These effects can lead to a new, intrinsically high-dimensional mechanism of baryogenesis. Baryon asymmetry might be produced due either to ``evaporation'' into the baby branes, or creation of the baryon number excess in collisions of two Brane Universes. As an example we discuss a possible cosmological scenario within the recently proposed ``Brane Inflation'' framework. Inflation is driven by displaced branes which slowly fall on top of each other. When the branes collide inflation stops and the Brane Universe reheats. During this non-equilibrium collision baryon number can be transported from one brane to another one. This results in the baryon number excess in our Universe which exactly equals to the hidden ``baryon number'' deficit in the other Brane Universe. © 1999

  15. Bacterial attachment to RO membranes surface-modified by concentration-polarization-enhanced graft polymerization.

    PubMed

    Bernstein, Roy; Belfer, Sofia; Freger, Viatcheslav

    2011-07-15

    Concentration polarization-enhanced radical graft polymerization, a facile surface modification technique, was examined as an approach to reduce bacterial deposition onto RO membranes and thus contribute to mitigation of biofouling. For this purpose an RO membrane ESPA-1 was surface-grafted with a zwitterionic and negatively and positively charged monomers. The low monomer concentrations and low degrees of grafting employed in modifications moderately reduced flux (by 20-40%) and did not affect salt rejection, yet produced substantial changes in surface chemistry, charge and hydrophilicity. The propensity to bacterial attachment of original and modified membranes was assessed using bacterial deposition tests carried out in a parallel plate flow setup using a fluorescent strain of Pseudomonas fluorescens. Compared to unmodified ESPA-1 the deposition (mass transfer) coefficient was significantly increased for modification with the positively charged monomer. On the other hand, a substantial reduction in bacterial deposition rates was observed for membranes modified with zwitterionic monomer and, still more, with very hydrophilic negatively charged monomers. This trend is well explained by the effects of surface charge (as measured by ζ-potential) and hydrophilicity (contact angle). It also well correlated with force distance measurements by AFM using surrogate spherical probes with a negative surface charge mimicking the bacterial surface. The positively charged surface showed a strong hysteresis with a large adhesion force, which was weaker for unmodified ESPA-1 and still weaker for zwitterionic surface, while negatively charged surface showed a long-range repulsion and negligible hysteresis. These results demonstrate the potential of using the proposed surface- modification approach for varying surface characteristics, charge and hydrophilicity, and thus minimizing bacterial deposition and potentially reducing propensity biofouling.

  16. From the 750 GeV diphoton resonance to multilepton excesses

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Bae, Kyu Jung; Chen, Chuan-Ren; Hamaguchi, Koichi

    2016-07-01

    Weakly coupled models for the 750 GeV diphoton resonance often invoke new particles carrying both color and/or electric charges to mediate loop-induced couplings of the resonance to two gluons and two photons. The new colored particles may not be stable and could decay into final states containing standard model particles. We consider an electroweak doublet of vectorlike quarks (VLQs) carrying electric charges of 5/3 and 2/3, respectively, which mediate the loop-induced couplings of the 750 GeV resonance. If the VLQ has a mass at around 1 TeV, it naturally gives rise to the observed diphoton signal strength while all couplingsmore » remain perturbative up to a high scale. At the same time, if the charge-5/3 VLQ decays into final states containing top quark and W boson, it would contribute to the multilepton excesses observed in both run 1 and run 2 data. It is also possible to incorporate a dark matter candidate in the decay final states to explain the observed relic density.« less

  17. Saturation current and collection efficiency for ionization chambers in pulsed beams.

    PubMed

    DeBlois, F; Zankowski, C; Podgorsak, E B

    2000-05-01

    Saturation currents and collection efficiencies in ionization chambers exposed to pulsed megavoltage photon and electron beams are determined assuming a linear relationship between 1/I and 1/V in the extreme near-saturation region, with I and V the chamber current and polarizing voltage, respectively. Careful measurements of chamber current against polarizing voltage in the extreme near-saturation region reveal a current rising faster than that predicted by the linear relationship. This excess current combined with conventional "two-voltage" technique for determination of collection efficiency may result in an up to 0.7% overestimate of the saturation current for standard radiation field sizes of 10X10 cm2. The measured excess current is attributed to charge multiplication in the chamber air volume and to radiation-induced conductivity in the stem of the chamber (stem effect). These effects may be accounted for by an exponential term used in conjunction with Boag's equation for collection efficiency in pulsed beams. The semiempirical model follows the experimental data well and accounts for both the charge recombination as well as for the charge multiplication effects and the chamber stem effect.

  18. Monte Carlo simulation and equation of state for flexible charged hard-sphere chain fluids: polyampholyte and polyelectrolyte solutions.

    PubMed

    Jiang, Hao; Adidharma, Hertanto

    2014-11-07

    The thermodynamic modeling of flexible charged hard-sphere chains representing polyampholyte or polyelectrolyte molecules in solution is considered. The excess Helmholtz energy and osmotic coefficients of solutions containing short polyampholyte and the osmotic coefficients of solutions containing short polyelectrolytes are determined by performing canonical and isobaric-isothermal Monte Carlo simulations. A new equation of state based on the thermodynamic perturbation theory is also proposed for flexible charged hard-sphere chains. For the modeling of such chains, the use of solely the structure information of monomer fluid for calculating the chain contribution is found to be insufficient and more detailed structure information must therefore be considered. Two approaches, i.e., the dimer and dimer-monomer approaches, are explored to obtain the contribution of the chain formation to the Helmholtz energy. By comparing with the simulation results, the equation of state with either the dimer or dimer-monomer approach accurately predicts the excess Helmholtz energy and osmotic coefficients of polyampholyte and polyelectrolyte solutions except at very low density. It also well captures the effect of temperature on the thermodynamic properties of these solutions.

  19. Concurrent application of charge using a novel circuit prevents heat-related coagulum formation during radiofrequency ablation.

    PubMed

    Lim, Bernard; Venkatachalam, Kalpathi L; Jahangir, Arshad; Johnson, Susan B; Asirvatham, Samuel J

    2008-08-01

    Thromboembolism resulting from coagulum formation on the catheter and electrode surfaces is a serious complication with radiofrequency ablation procedures for heart rhythm disorders. Why coagulum occurs despite therapeutic heparinization is unclear. In this report, we demonstrate a novel approach to minimize coagulum formation based on the electromolecular characteristics of fibrinogen. Atomic force microscopy was used to establish that fibrinogen deposited on surfaces underwent conformational changes that resulted in spontaneous clot formation. We then immersed ablation catheters that were uncharged, negatively, or positively charged in heparinized blood for 30 minutes and noted the extent of clot formation. In separate experiments, ablation catheters were sutured to the ventricle of an excised porcine heart immersed in whole, heparinized blood and radiofrequency ablation performed for 5 minutes with and without charge delivered to the catheter tips. Electron microscopy of the catheter tips showed surface coverage of fibrin clot of the catheter to be 33.8% for negatively charged catheters, compared with 84.7% (P = 0.01) in noncharged catheters. There was no significant difference in surface coverage of fibrin clot between positively charged catheters (93.8%) and noncharged catheters (84.7%, P = ns). In contrast, the thickness of surface clot coverage for positively charged catheters was 87.5%, compared with 28.45% (P= 0.03) for noncharged catheters and 11.25% (P = 0.03) for negatively charged catheters, compared with noncharged catheters. We describe a novel method of placing negative charge on electrodes during ablation that reduced coagulum formation. This may decrease thromboembolism-related complications with radiofrequency ablation procedures.

  20. Anionic Cerium Oxide Nanoparticles Protect Plant Photosynthesis from Abiotic Stress by Scavenging Reactive Oxygen Species.

    PubMed

    Wu, Honghong; Tito, Nicholas; Giraldo, Juan P

    2017-11-28

    Plant abiotic stress leads to accumulation of reactive oxygen species (ROS) and a consequent decrease in photosynthetic performance. We demonstrate that a plant nanobionics approach of localizing negatively charged, sub-11 nm, spherical cerium oxide nanoparticles (nanoceria) inside chloroplasts in vivo augments ROS scavenging and photosynthesis of Arabidopsis thaliana plants under excess light (2000 μmol m -2 s -1 , 1.5 h), heat (35 °C, 2.5 h), and dark chilling (4 °C, 5 days). Poly(acrylic acid) nanoceria (PNC) with a hydrodynamic diameter (10.3 nm)-lower than the maximum plant cell wall porosity-and negative ζ-potential (-16.9 mV) exhibit significantly higher colocalization (46%) with chloroplasts in leaf mesophyll cells than aminated nanoceria (ANC) (27%) of similar size (12.6 nm) but positive charge (9.7 mV). Nanoceria are transported into chloroplasts via nonendocytic pathways, influenced by the electrochemical gradient of the plasma membrane potential. PNC with a low Ce 3+ /Ce 4+ ratio (35.0%) reduce leaf ROS levels by 52%, including hydrogen peroxide, superoxide anion, and hydroxyl radicals. For the latter ROS, there is no known plant enzyme scavenger. Plants embedded with these PNC that were exposed to abiotic stress exhibit an increase up to 19% in quantum yield of photosystem II, 67% in carbon assimilation rates, and 61% in Rubisco carboxylation rates relative to plants without nanoparticles. In contrast, PNC with high Ce 3+ /Ce 4+ ratio (60.8%) increase overall leaf ROS levels and do not protect photosynthesis from oxidative damage during abiotic stress. This study demonstrates that anionic, spherical, sub-11 nm PNC with low Ce 3+ /Ce 4+ ratio can act as a tool to study the impact of oxidative stress on plant photosynthesis and to protect plants from abiotic stress.

  1. Effect of electrical polarization of hydroxyapatite ceramics on new bone formation.

    PubMed

    Itoh, S; Nakamura, S; Kobayashi, T; Shinomiya, K; Yamashita, K; Itoh, S

    2006-03-01

    Large surface charges can be induced on hydroxyapatite (HAp) ceramics by proton transport polarization, but this does not affect beta-tricalcium phosphate (TCP) because of its low polarizability. We wished to examine differences in osteogenic cell activity and new bone growth between positively or negatively surface-charged HAp and HAp/TCP plates using a calvarial bone defect model. In the first group of rats, test pieces were placed with their positively charged surfaces face down on the dura mater. In the second group, test pieces were placed with their negatively charged surfaces face down on the dura mater. A third group received noncharged test pieces. Histological examination, including enzymatic staining for osteoblasts and osteoclasts, was carried out. While no bone formation was observed at the pericranium, direct bone formation on the cranial bone debris and new bone growth expanded from the margins of the sites of injury to bridge across both the positively and negatively charged surfaces of HAp and HAp/TCP plates occurred. Electrical polarization of implanted plates, including positive charge, led to enhanced osteoblast activity, though decreased osteoclast activity was seen on the positively charged plate surface. Thus, polarization of HAp ceramics may modulate new bone formation and resorption.

  2. Rational Design of Multilayer Collagen Nanosheets with Compositional and Structural Control.

    PubMed

    Jiang, Tao; Vail, Owen A; Jiang, Zhigang; Zuo, Xiaobing; Conticello, Vincent P

    2015-06-24

    Two collagen-mimetic peptides, CP(+) and CP(-), are reported in which the sequences comprise a multiblock architecture having positively charged N-terminal (Pro-Arg-Gly)3 and negatively charged C-terminal (Glu-Hyp-Gly)3 triad extensions, respectively. CP(+) rapidly self-associates into positively charged nanosheets based on a monolayer structure. In contrast, CP(-) self-assembles to form negatively charged monolayer nanosheets at a much slower rate, which can be accelerated in the presence of calcium(II) ion. A 2:1 mixture of unassociated CP(-) peptide with preformed CP(+) nanosheets generates structurally defined triple-layer nanosheets in which two CP(-) monolayers have formed on the identical surfaces of the CP(+) nanosheet template. Experimental data from electrostatic force microscopy (EFM) image analysis, zeta potential measurements, and charged nanoparticle binding assays support a negative surface charge state for the triple-layer nanosheets, which is the reverse of the positive surface charge state observed for the CP(+) monolayer nanosheets. The electrostatic complementarity between the CP(+) and CP(-) triple helical cohesive ends at the layer interfaces promotes a (CP(-)/CP(+)/CP(-)) compositional gradient along the z-direction of the nanosheet. This structurally informed approach represents an attractive strategy for the fabrication of two-dimensional nanostructures with compositional control.

  3. Electrical structure in two thunderstorm anvil clouds

    NASA Technical Reports Server (NTRS)

    Marshall, Thomas C.; Rust, W. David; Winn, William P.; Gilbert, Kenneth E.

    1989-01-01

    Electrical structures in two thunderstorm anvil clouds (or 'anvils'), one in New Mexico, the other in Oklahoma, were investigated, using measurements of electric field by balloon-carried instruments and a one-dimensional model to calculate the time and spatial variations of electrical parameters in the clear air below the anvil. The electric field soundings through the two thunderstorm anvils showed similar charge structures; namely, negatively charged screening layers on the top and the bottom surfaces, a layer of positive charge in the interior, and one or two layers of zero charge. It is suggested that the positive charge originated in the main positive charge region normally found at high altitudes in the core of thunderclouds, and the negatively charged layers probably formed as screening layers, resulting from the discontinuity in the electrical conductivity at the cloud boundaries.

  4. Interaction between electrically charged droplets in microgravity

    NASA Astrophysics Data System (ADS)

    Brandenbourger, Martin; Caps, Herve; Hardouin, Jerome; Vitry, Youen; Boigelot, Bernard; Dorbolo, Stephane; Grasp Team; Beams Collaboration

    2015-11-01

    The past ten years, electrically charged droplets have been studied tremendously for their applications in industry (electrospray, electrowetting,...). However, charged droplets are also present in nature. Indeed, it has been shown that the droplets falling from thunderclouds possess an excess of electric charges. Moreover, some research groups try to use the electrical interaction between drops in order to control the coalescence between cloud droplets and control rain generation. The common way to study this kind of system is to make hypothesis on the interaction between two charged drops. Then, these hypothesis are extended to a system of thousands of charged droplets. Thanks to microgravity conditions, we were able to study the interaction between two electrically charged droplets. In practice, the charged droplets were propelled one in front of the other at low speed (less than 1 m/s). The droplets trajectory is studied for various charges and volumes. The repulsion between two charged drops is correctly fitted by a simple Coulomb repulsion law. In the case of attractive interactions, we discuss the collisions observed as a function of the droplets speed, volume and electric charges. Thanks to FNRS for financial support.

  5. Influence of natural organic matter on equilibrium adsorption of neutral and charged pharmaceuticals onto activated carbon.

    PubMed

    de Ridder, D J; Verliefde, A R D; Heijman, S G J; Verberk, J Q J C; Rietveld, L C; van der Aa, L T J; Amy, G L; van Dijk, J C

    2011-01-01

    Natural organic matter (NOM) can influence pharmaceutical adsorption onto granular activated carbon (GAC) by direct adsorption competition and pore blocking. However, in the literature there is limited information on which of these mechanisms is more important and how this is related to NOM and pharmaceutical properties. Adsorption batch experiments were carried out in ultrapure, waste- and surface water and fresh and NOM preloaded GAC was used. Twenty-one pharmaceuticals were selected with varying hydrophobicity and with neutral, negative or positive charge. The influence of NOM competition and pore blocking could not be separated. However, while reduction in surface area was similar for both preloaded GACs, up to 50% lower pharmaceutical removal was observed on wastewater preloaded GAC. This was attributed to higher hydrophobicity of wastewater NOM, indicating that NOM competition may influence pharmaceutical removal more than pore blocking. Preloaded GAC was negatively charged, which influenced removal of charged pharmaceuticals significantly. At a GAC dose of 6.7 mg/L, negatively charged pharmaceuticals were removed for 0-58%, while removal of positively charged pharmaceuticals was between 32-98%. Charge effects were more pronounced in ultrapure water, as it contained no ions to shield the surface charge. Solutes with higher log D could compete better with NOM, resulting in higher removal.

  6. Solar bus regulator and battery charger for IMP's H, I, and J

    NASA Technical Reports Server (NTRS)

    Paulkovich, J.

    1972-01-01

    Interplanetary Monitoring Probe (IMP) spacecrafts H, I, and J utilize a direct energy transfer (DET) type of power system operating from a solar array source. A shunt type of regulator prevents the bus voltage from exceeding a preset voltage level. The power system utilizes a single differential amplifier with dual outputs to control the battery charge/shunt regulator and the discharge regulator. A two-voltage level, current limited, series charger and a current sensor control battery state of charge of the silver-cadmium battery pack. Premature termination of the battery charge is prevented by a power available gate that also initiates charge current to the battery upon availability of excess power.

  7. Presence of negative charge on the basal planes of New York talc.

    PubMed

    Burdukova, E; Becker, M; Bradshaw, D J; Laskowski, J S

    2007-11-01

    Potentiometric titration measurements as well as rheological measurements of talc aqueous suspensions indicate that the behavior of the New York talc particles is consistent with the presence of a negative charge on their basal planes. The possibility of the presence of a negative electrical charge on the basal planes of talc particles is analyzed in this paper. Samples of New York talc were studied using electron microprobe analysis and dehydration techniques and the exact chemical formula of New York talc was determined. It was found that there exists a deficiency of protons in the tetrahedral layers of talc, resulting from substitution of Si(4+) ions with Al(3+) and Ti(3+) ions. The comparison of the level of substitution of Si(4+) ions with ions of a lower valency was found to be of a similar order of magnitude as that found in other talc deposits. This strongly points to the presence of a negative charge on the talc basal planes.

  8. Electrochemical energy storage devices comprising self-compensating polymers

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Johnson, Paul; Bautista-Martinez, Jose Antonio; Friesen, Cody

    The disclosed technology relates generally to devices comprising conductive polymers and more particularly to electrochemical devices comprising self-compensating conductive polymers. In one aspect, electrochemical energy storage device comprises a negative electrode comprising an active material including a redox-active polymer. The device additionally comprises a positive electrode comprising an active material including a redox-active polymer. The device further comprises an electrolyte material interposed between the negative electrode and positive electrode and configured to conduct mobile counterions therethrough between the negative electrode and positive electrode. At least one of the negative electrode redox-active polymer and the positive electrode redox-active polymer comprises amore » zwitterionic polymer unit configured to reversibly switch between a zwitterionic state in which the zwitterionic polymer unit has first and second charge centers having opposite charge states that compensate each other, and a non-zwitterionic state in which the zwitterionic polymer unit has one of the first and second charge centers whose charge state is compensated by mobile counterions.« less

  9. Effects of O 2 and N 2/H 2 plasma treatments on the neuronal cell growth on single-walled carbon nanotube paper scaffolds

    NASA Astrophysics Data System (ADS)

    Yoon, Ok Ja; Lee, Hyun Jung; Jang, Yeong Mi; Kim, Hyun Woo; Lee, Won Bok; Kim, Sung Su; Lee, Nae-Eung

    2011-08-01

    The O 2 and N 2/H 2 plasma treatments of single-walled carbon nanotube (SWCNT) papers as scaffolds for enhanced neuronal cell growth were conducted to functionalize their surfaces with different functional groups and to roughen their surfaces. To evaluate the effects of the surface roughness and functionalization modifications of the SWCNT papers, we investigated the neuronal morphology, mitochondrial membrane potential, and acetylcholine/acetylcholinesterase levels of human neuroblastoma during SH-SY5Y cell growth on the treated SWCNT papers. Our results demonstrated that the plasma-chemical functionalization caused changes in the surface charge states with functional groups with negative and positive charges and then the increased surface roughness enhanced neuronal cell adhesion, mitochondrial membrane potential, and the level of neurotransmitter in vitro. The cell adhesion and mitochondrial membrane potential on the negatively charged SWCNT papers were improved more than on the positively charged SWCNT papers. Also, measurements of the neurotransmitter level showed an enhanced acetylcholine level on the negatively charged SWCNT papers compared to the positively charged SWCNT papers.

  10. Important parameters affecting the cell voltage of aqueous electrical double-layer capacitors

    NASA Astrophysics Data System (ADS)

    Wu, Tzu-Ho; Hsu, Chun-Tsung; Hu, Chi-Chang; Hardwick, Laurence J.

    2013-11-01

    This study discusses and demonstrates how the open-circuit potential and charges stored in the working potential window on positive and negative electrodes affect the cell voltage of carbon-based electrical double-layer capacitors (EDLCs) in aqueous electrolytes. An EDLC consisting of two activated carbon electrodes is employed as the model system for identifying these key parameters although the potential window of water decomposition can be simply determined by voltammetric methods. First, the capacitive performances of an EDLC with the same charge on positive and negative electrodes are evaluated by cyclic voltammetric, charge-discharge, electrochemical impedance spectroscopic (EIS) analyses, and inductance-capacitance-resistance meter (LCR meter). The principles for obtaining the highest acceptable cell voltage of such symmetric ECs with excellent reversibility and capacitor-like behaviour are proposed. Aqueous charge-balanced EDLCs can be operated as high as 2.0 V with high energy efficiency (about 90%) and only 4% capacitance loss after the 600-cycle stability checking. The necessity of charge balance (but not capacitance balance) for positive and negative electrodes is substantiated from the lower acceptable cell voltage of charge-unbalanced EDLCs.

  11. Hindered Diffusion in Polymeric Solutions Studied by Fluorescence Correlation Spectroscopy

    PubMed Central

    Zustiak, Silviya P.; Nossal, Ralph; Sackett, Dan L.

    2011-01-01

    Diffusion of molecules in the crowded and charged interior of the cell has long been of interest for understanding cellular processes. Here, we introduce a model system of hindered diffusion that includes both crowding and binding. In particular, we obtained the diffusivity of the positively charged protein, ribonuclease A (RNase), in solutions of dextrans of various charges (binding) and concentrations (crowding), as well as combinations of both, in a buffer of physiological ionic strength. Using fluorescence correlation spectroscopy, we observed that the diffusivity of RNase was unaffected by the presence of positively charged or neutral dextrans in the dilute regime but was affected by crowding at higher polymer concentrations. Conversely, protein diffusivity was significantly reduced by negatively charged dextrans, even at 0.4 μM (0.02% w/v) dextran. The diffusivity of RNase decreased with increasing concentrations of negative dextran, and the amount of bound RNase increased until it reached a plateau of ∼80% bound RNase. High salt concentrations were used to establish the electrostatic nature of the binding. Binding of RNase to the negatively charged dextrans was further confirmed by ultrafiltration. PMID:21723836

  12. Changing Delay Discounting in the Light of the Competing Neurobehavioral Decision Systems Theory: A Review

    ERIC Educational Resources Information Center

    Koffarnus, Mikhail N.; Jarmolowicz, David P.; Mueller, E. Terry; Bickel, Warren K.

    2013-01-01

    Excessively devaluing delayed reinforcers co-occurs with a wide variety of clinical conditions such as drug dependence, obesity, and excessive gambling. If excessive delay discounting is a trans-disease process that underlies the choice behavior leading to these and other negative health conditions, efforts to change an individual's discount rate…

  13. Adverse Effects of Excess Residual PbI2 on Photovoltaic Performance, Charge Separation, and Trap-State Properties in Mesoporous Structured Perovskite Solar Cells.

    PubMed

    Wang, Hao-Yi; Hao, Ming-Yang; Han, Jun; Yu, Man; Qin, Yujun; Zhang, Pu; Guo, Zhi-Xin; Ai, Xi-Cheng; Zhang, Jian-Ping

    2017-03-17

    Organic-inorganic halide perovskite solar cells have rapidly come to prominence in the photovoltaic field. In this context, CH 3 NH 3 PbI 3 , as the most widely adopted active layer, has been attracting great attention. Generally, in a CH 3 NH 3 PbI 3 layer, unreacted PbI 2 inevitably coexists with the perovskite crystals, especially following a two-step fabrication process. There appears to be a consensus that an appropriate amount of unreacted PbI 2 is beneficial to the overall photovoltaic performance of a device, the only disadvantageous aspect of excess residual PbI 2 being viewed as its insulating nature. However, the further development of such perovskite-based devices requires a deeper understanding of the role of residual PbI 2 . In this work, PbI 2 -enriched and PbI 2 -controlled perovskite films, as two extreme cases, have been prepared by modulating the crystallinity of a pre-deposited PbI 2 film. The effects of excess residual PbI 2 have been elucidated on the basis of spectroscopic and optoelectronic studies. The initial charge separation, the trap-state density, and the trap-state distribution have all been found to be adversely affected in PbI 2 -enriched devices, to the detriment of photovoltaic performance. This leads to a biphasic recombination process and accelerates the charge carrier recombination dynamics. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  14. Proton transfer to charged platinum electrodes. A molecular dynamics trajectory study.

    PubMed

    Wilhelm, Florian; Schmickler, Wolfgang; Spohr, Eckhard

    2010-05-05

    A recently developed empirical valence bond (EVB) model for proton transfer on Pt(111) electrodes (Wilhelm et al 2008 J. Phys. Chem. C 112 10814) has been applied in molecular dynamics (MD) simulations of a water film in contact with a charged Pt surface. A total of seven negative surface charge densities σ between -7.5 and -18.9 µC cm(-2) were investigated. For each value of σ, between 30 and 84 initial conditions of a solvated proton within a water slab were sampled, and the trajectories were integrated until discharge of a proton occurred on the charged surfaces. We have calculated the mean rates for discharge and for adsorption of solvated protons within the adsorbed water layer in contact with the metal electrode as a function of surface charge density. For the less negative values of σ we observe a Tafel-like exponential increase of discharge rate with decreasing σ. At the more negative values this exponential increase levels off and the discharge process is apparently transport limited. Mechanistically, the Tafel regime corresponds to a stepwise proton transfer: first, a proton is transferred from the bulk into the contact water layer, which is followed by transfer of a proton to the charged surface and concomitant discharge. At the more negative surface charge densities the proton transfer into the contact water layer and the transfer of another proton to the surface and its discharge occur almost simultaneously.

  15. Ultrasonic and spectral studies on charge transfer complexes of anisole and certain aromatic amines

    NASA Astrophysics Data System (ADS)

    Rajesh, R.; Raj Muhamed, R.; Justin Adaikala Baskar, A.; Kannappan, V.

    2016-10-01

    Stability constants of two complexes of anisole with aniline and N-methylaniline (NMA) are determined from the measured ultrasonic velocity in n-hexane medium at four different temperatures. Acoustic and excess thermo acoustic parameters [excess ultrasonic velocity (uE), excess molar volume (VE), excess internal pressure (πiE)] are reported for these systems at four different temperatures. The trend in acoustic and excess parameters with concentration in the two systems establishes the formation of hydrogen bonded complexes between anisole and the two amines. Thermodynamic properties are computed for the two complexes from the variation in K with temperature. The formation of these complexes is also established by UV spectral method and their spectral characteristics and stability constants are determined. K values of these complexes obtained by ultrasonic and UV spectroscopic techniques agree well. Aniline forms more stable complex than N-methylaniline with anisole in n-hexane medium.

  16. Differential effects of DEAE negative mode chromatography and gel-filtration chromatography on the charge status of Helicobacter pylori neutrophil-activating protein

    PubMed Central

    Pan, Timothy; Tzeng, Huey-Fen

    2017-01-01

    Helicobacter pylori neutrophil-activating protein (HP-NAP) is involved in H. pylori-associated gastric inflammation. HP-NAP is also a vaccine candidate, a possible drug target, and a potential diagnostic marker for H. pylori-associated diseases. Previously, we purified recombinant HP-NAP by one-step diethylaminoethyl (DEAE) negative mode chromatography by collecting the unbound fraction at pH 8.0 at 4°C. It remains unclear why HP-NAP does not bind to DEAE resins at the pH above its isoelectric point during the purification. To investigate how pH affects the surface net charge of HP-NAP and its binding to DEAE resins during the purification, recombinant HP-NAP expressed in Escherichia coli was subjected to DEAE negative mode chromatography at pH ranging from 7.0 to 9.0 at 25°C and the surface charge of purified HP-NAP was determined by capillary electrophoresis. A minimal amount of HP-NAP was detected in the elution fraction of DEAE Sepharose resin at pH 8.5, whereas recombinant HP-NAP was detected in the elution fraction of DEAE Sephadex resin only at pH 7.0 and 8.0. The purified recombinant HP-NAP obtained from the unbound fractions was not able to bind to DEAE resins at pH 7.0 to 9.0. In addition, the surface charge of the purified HP-NAP was neutral at pH 7.0 to 8.0 and was either neutral or slightly negative at pH 8.5 and 9.0. However, recombinant HP-NAP purified from gel-filtration chromatography was able to bind to DEAE Sepharose resin at pH 7.0 to 9.0 and DEAE Sephadex resin at pH 7.0. At pH 8.5 and 9.0, only the negatively charged species of HP-NAP were found. Thus, recombinant HP-NAP with different charge status can be differentially purified by DEAE negative mode chromatography and gel-filtration chromatography. Furthermore, the charge distribution on the surface of HP-NAP, the presence of impure proteins, and the overall net charge of the resins all affect the binding of HP-NAP to DEAE resins during the negative purification. PMID:28328957

  17. Differential effects of DEAE negative mode chromatography and gel-filtration chromatography on the charge status of Helicobacter pylori neutrophil-activating protein.

    PubMed

    Hong, Zhi-Wei; Yang, Yu-Chi; Pan, Timothy; Tzeng, Huey-Fen; Fu, Hua-Wen

    2017-01-01

    Helicobacter pylori neutrophil-activating protein (HP-NAP) is involved in H. pylori-associated gastric inflammation. HP-NAP is also a vaccine candidate, a possible drug target, and a potential diagnostic marker for H. pylori-associated diseases. Previously, we purified recombinant HP-NAP by one-step diethylaminoethyl (DEAE) negative mode chromatography by collecting the unbound fraction at pH 8.0 at 4°C. It remains unclear why HP-NAP does not bind to DEAE resins at the pH above its isoelectric point during the purification. To investigate how pH affects the surface net charge of HP-NAP and its binding to DEAE resins during the purification, recombinant HP-NAP expressed in Escherichia coli was subjected to DEAE negative mode chromatography at pH ranging from 7.0 to 9.0 at 25°C and the surface charge of purified HP-NAP was determined by capillary electrophoresis. A minimal amount of HP-NAP was detected in the elution fraction of DEAE Sepharose resin at pH 8.5, whereas recombinant HP-NAP was detected in the elution fraction of DEAE Sephadex resin only at pH 7.0 and 8.0. The purified recombinant HP-NAP obtained from the unbound fractions was not able to bind to DEAE resins at pH 7.0 to 9.0. In addition, the surface charge of the purified HP-NAP was neutral at pH 7.0 to 8.0 and was either neutral or slightly negative at pH 8.5 and 9.0. However, recombinant HP-NAP purified from gel-filtration chromatography was able to bind to DEAE Sepharose resin at pH 7.0 to 9.0 and DEAE Sephadex resin at pH 7.0. At pH 8.5 and 9.0, only the negatively charged species of HP-NAP were found. Thus, recombinant HP-NAP with different charge status can be differentially purified by DEAE negative mode chromatography and gel-filtration chromatography. Furthermore, the charge distribution on the surface of HP-NAP, the presence of impure proteins, and the overall net charge of the resins all affect the binding of HP-NAP to DEAE resins during the negative purification.

  18. Charge Separation and Recombination at Polymer-Fullerene Heterojunctions: Delocalization and Hybridization Effects.

    PubMed

    D'Avino, Gabriele; Muccioli, Luca; Olivier, Yoann; Beljonne, David

    2016-02-04

    We address charge separation and recombination in polymer/fullerene solar cells with a multiscale modeling built from accurate atomistic inputs and accounting for disorder, interface electrostatics and genuine quantum effects on equal footings. Our results show that bound localized charge transfer states at the interface coexist with a large majority of thermally accessible delocalized space-separated states that can be also reached by direct photoexcitation, thanks to their strong hybridization with singlet polymer excitons. These findings reconcile the recent experimental reports of ultrafast exciton separation ("hot" process) with the evidence that high quantum yields do not require excess electronic or vibrational energy ("cold" process), and show that delocalization, by shifting the density of charge transfer states toward larger effective electron-hole radii, may reduce energy losses through charge recombination.

  19. Method of casting articles of a bulk-solidifying amorphous alloy

    DOEpatents

    Lin, X.; Johnson, W.L.; Peker, A.

    1998-08-25

    A casting charge of a bulk-solidifying amorphous alloy is cast into a mold from a temperature greater than its crystallized melting temperature, and permitted to solidify to form an article. The oxygen content of the casting charge is limited to an operable level, as excessively high oxygen contents produce premature crystallization during the casting operation. During melting, the casting charge is preferably heated to a temperature above a threshold temperature to eliminate heterogeneous crystallization nucleation sites within the casting charge. The casting charge may be cast from above the threshold temperature, or it may be cooled to the casting temperature of more than the crystallized melting point but not more than the threshold temperature, optionally held at this temperature for a period of time, and thereafter cast. 8 figs.

  20. Method of casting articles of a bulk-solidifying amorphous alloy

    DOEpatents

    Lin, Xianghong; Johnson, William L.; Peker, Atakan

    1998-01-01

    A casting charge of a bulk-solidifying amorphous alloy is cast into a mold from a temperature greater than its crystallized melting temperature, and permitted to solidify to form an article. The oxygen content of the casting charge is limited to an operable level, as excessively high oxygen contents produce premature crystallization during the casting operation. During melting, the casting charge is preferably heated to a temperature above a threshold temperature to eliminate heterogeneous crystallization nucleation sites within the casting charge. The casting charge may be cast from above the threshold temperature, or it may be cooled to the casting temperature of more than the crystallized melting point but not more than the threshold temperature, optionally held at this temperature for a period of time, and thereafter cast.

  1. Functionalized nanoparticle interactions with polymeric membranes

    PubMed Central

    Ladner, D.A.; Steele, M.; Weir, A.; Hristovski, K.; Westerhoff, P.

    2011-01-01

    A series of experiments was performed to measure the retention of a class of functionalized nanoparticles (NPs) onporous (microfiltration and ultrafiltration) membranes. The findings impact engineered water and wastewater treatment using membrane technology, characterization and analytical schemes for NP detection, and the use of NPs in waste treatment scenarios. The NPs studied were composed of silver, titanium dioxide, and gold; had organic coatings to yield either positive or negative surface charge; and were between 2 and 10 nm in diameter. NP solutions were applied to polymeric membranes composed of different materials and pore sizes (ranging from ~2 nm [3 kDa molecular weight cutoff] to 0.2 μm). Greater than 99% rejection was observed of positively charged NPs by negatively charged membranes even though pore diameters were up to 20 times the NP diameter; thus, sorption caused rejection. Negatively charged NPs were less well rejected, but behavior was dependant not only on surface functionality but on NP core material (Ag, TiO2, or Au). NP rejection depended more upon NP properties than membrane properties; all of the negatively charged polymeric membranes behaved similarly. The NP-membrane interaction behavior fell into four categories, which are defined and described here. PMID:22177020

  2. Increasing binding density of yeast cells by control of surface charge with allylamine grafting to ion modified polymer surfaces.

    PubMed

    Tran, Clara T H; Kondyurin, Alexey; Chrzanowski, Wojciech; Bilek, Marcela M M; McKenzie, David R

    2014-10-01

    Plasma immersion ion implantation (PIII) treatment of polymers creates a biointerface capable of direct covalent immobilization of biomolecules. The immobilization of protein molecules is achieved by covalent bonds formed between embedded radicals on the treated surface and amino acid side chains and cells can be immobilized through cell-wall proteins. The attachment density of negatively charged entities on a PIII treated surface is inhibited by its negative surface charge at neutral pH. To reduce the negative charge of PIII treated surfaces in phosphate buffer (pH 7.4, 11mM), we develop an effective approach of grafting allylamine monomers onto the treated surface. The results reveal reactions between allylamine and radicals on the PIII treated surface. One of these triggers polymerization, increasing the number of amine groups grafted. As a consequence, the PIII treated polystyrene surface after allylamine exposure becomes more hydrophobic and less negatively charged in phosphate buffer. Using yeast cells as an example, we have shown a significant improvement (6-15 times) of cell density immobilized on the PIII treated surface after exposure to allylamine. Copyright © 2014 Elsevier B.V. All rights reserved.

  3. High-energy e- /e+ spectrometer via coherent interaction in a bent crystal

    NASA Astrophysics Data System (ADS)

    Bagli, Enrico; Guidi, Vincenzo; Howard, Alexander

    2018-01-01

    We propose a novel spectrometer based on the crystal channeling effect capable of discriminating between positive and negative particles well beyond the TeV energy scale. The atomic order of a crystalline structure generates an electrostatic field built up by all the atoms in the crystals, which confines charged particle trajectories between neighbouring atomic planes. Through such an interaction in a tiny curved crystal, the same dynamical action on the highest energy particles as that of a huge superconducting magnet is achieved. Depending on the charge sign, points of equilibrium of the oscillatory motion under channeling lie between or on atomic planes for positive and negative particles, respectively, forcing positive particles to stably oscillate far from the planes, while negative ones repeatedly cross them. The different interaction rate with atomic planes causes a tremendous discrepancy between the deflection efficiency of positive and negative particles under channeling. We suggest the use of interactions between charged particles and oriented bent crystals as a novel non-cryogenic passive charge spectrometer to aid the search for dark matter in the Universe in satellite-borne experiment. The limited angular acceptance makes this technique particularly suited for directional local sources of energetic charged particles.

  4. Microelectrophoretic study of calcium oxalate monohydrate in macromolecular solutions

    NASA Technical Reports Server (NTRS)

    Curreri, P. A.; Onoda, G. Y., Jr.; Finlayson, B.

    1987-01-01

    Electrophoretic mobilities were measured for calcium oxalate monohydrate (COM) in solutions containing macromolecules. Two mucopolysaccharides (sodium heparin and chondroitin sulfate) and two proteins (positively charged lysozyme and negatively charged bovine serum albumin) were studied as adsorbates. The effects of pH, calcium oxalate surface charge (varied by calcium or oxalate ion activity), and citrate concentration were investigated. All four macromolecules showed evidence for adsorption. The macromolecule concentrations needed for reversing the surface charge indicated that the mucopolysaccharides have greater affinity for the COM surface than the proteins. Citrate ions at high concentrations appear to compete effectively with the negative protein for surface sites but show no evidence for competing with the positively charged protein.

  5. Stepped electrophoresis for movement and concentration of DNA

    DOEpatents

    Miles, Robin R.; Wang, Amy Wei-Yun; Mariella, Jr., Raymond P.

    2005-03-15

    A fluidic channel patterned with a series of thin-film electrodes makes it possible to move and concentrate DNA in a fluid passing through the fluidic channel. The DNA has an inherent negative charge and by applying a voltage between adjacent electrodes the DNA is caused to move. By using a series of electrodes, when one electrode voltage or charge is made negative with respect to adjacent electrodes, the DNA is repelled away from this electrode and attached to a positive charged electrode of the series. By sequentially making the next electrode of the series negative, the DNA can be moved to and concentrated over the remaining positive electrodes.

  6. Neutralization by a Corona Discharge Ionizer in Nitrogen Atmosphere

    NASA Astrophysics Data System (ADS)

    Ikeuchi, Toru; Takahashi, Kazunori; Ohkubo, Takahiro; Fujiwara, Tamiya

    An electrostatic neutralization of multilayer-loading silicon wafers is demonstrated using a corona discharge ionizer in nitrogen atmosphere, where ac and dc voltages are applied to two needle electrodes for generation of the negative- and positive-charged particles, respectively. We observe a surface potential of the silicon wafer decreases from ±1kV to ±20V within three seconds. Moreover, the density profiles of the charged particles generated by the electrodes are experimentally and theoretically investigated in nitrogen and air atmospheres. Our results show the possibility that the negative-charged particles contributing to the electrostatic neutralization are electrons and negative ions in nitrogen and air atmospheres, respectively.

  7. Adhesion signals of phospholipid vesicles at an electrified interface.

    PubMed

    DeNardis, Nadica Ivošević; Žutić, Vera; Svetličić, Vesna; Frkanec, Ruža

    2012-09-01

    General adhesion behavior of phospholipid vesicles was examined in a wide range of potentials at the mercury electrode by recording time-resolved adhesion signals. It was demonstrated that adhesion-based detection is sensitive to polar headgroups in phospholipid vesicles. We identified a narrow potential window around the point of zero charge of the electrode where the interaction of polar headgroups of phosphatidylcholine vesicles with the substrate is manifested in the form of bidirectional signals. The bidirectional signal is composed of the charge flow due to the nonspecific interaction of vesicle adhesion and spreading and of the charge flow due to a specific interaction of the negatively charged electrode and the most exposed positively charged choline headgroups. These signals are expected to appear only when the electrode surface charge density is less than the surface charge density of the choline groups at the contact interface. In comparison, for the negatively charged phosphatidylserine vesicles, we identified the potential window at the mercury electrode where charge compensation takes place, and bidirectional signals were not detected.

  8. Maintenance of coat protein N-terminal net charge and not primary sequence is essential for zucchini yellow mosaic virus systemic infectivity.

    PubMed

    Kimalov, Boaz; Gal-On, Amit; Stav, Ran; Belausov, Eduard; Arazi, Tzahi

    2004-11-01

    Zucchini yellow mosaic virus (ZYMV) surface exposed coat protein (CP) N-terminal domain (Nt) is 43 aa long and contains an equal number of positively and negatively charged amino acid residues (CP-Nt net charge = 0). A ZYMV-AGII truncation mutant lacking the first 20 aa of its CP-Nt (AGII-CP Delta 20; CP-Nt net charge = +2) was found to be systemically non-infectious even though AGII mutants harbouring larger CP-Nt deletions were previously demonstrated to be fully infectious. Nevertheless, AGII-CP Delta 20 infectivity was restored by fusion to its CP-Nt two Asp residues or a negatively charged Myc peptide, both predicted to neutralize CP-Nt net positive charge. To evaluate further the significance of CP-Nt net charge for AGII infectivity, a series of CP-Nt net charge mutants was generated and analysed for systemic infectivity of squash plants. AGII-CP(KKK) harbouring a CP-Nt amino fusion of three Lys residues (CP-Nt net charge = +3) was not systemically infectious. Addition of up to four Asp residues to CP-Nt did not abolish virus infectivity, although certain mutants were genetically unstable and had delayed infectivity. Addition of five negatively charged residues abolished infectivity (AGII-CP(DDDDD); CP-Nt net charge = -5) even though a recombinant CP(DDDDD) could assemble into potyviral-like particle in bacteria. Neutralization of CP-Nt net charge by fusing Asp or Lys residues recovered infectivity of AGII-CP(KKK) and AGII-CP(DDDDD). GFP-tagging of these mutants has demonstrated that both viruses have defective cell-to-cell movement. Together, these findings suggest that maintenance of CP-Nt net charge and not primary sequence is essential for ZYMV infectivity.

  9. Negative charge emission due to excimer laser bombardment of sodium trisilicate glass

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Langford, S.C.; Jensen, L.C.; Dickinson, J.T.

    We describe measurements of negative charge emission accompanying irradiation of sodium trisilicate glass (Na{sub 2}O{center dot}3SiO{sub 2}) with 248-nm excimer laser light at fluences on the order of 2 J/cm{sup 2} per pulse, i.e., at the threshold for ablative etching of the glass surface. The negative charge emission consists of a very prompt photoelectron burst coincident with the laser pulse, followed by a much slower plume of electrons and negative ions traveling with a high density cloud of positive ions, previously identified as primarily Na{sup +}. Using combinations of {bold E} and {bold B} fields in conjunction with time-of-flight methods,more » the negative ions were successfully separated from the plume and tentatively identified as O{sup {minus}}, Si{sup {minus}}, NaO{sup {minus}}, and perhaps NaSi{sup {minus}}. These negative species are probably formed by gas phase collisions in the near-surface region which result in electron attachment.« less

  10. Universal scaling laws for the disintegration of electrified drops

    PubMed Central

    Collins, Robert T.; Sambath, Krishnaraj; Harris, Michael T.; Basaran, Osman A.

    2013-01-01

    Drops subjected to strong electric fields emit charged jets from their pointed tips. The disintegration of such jets into a spray consisting of charged droplets is common to electrospray ionization mass spectrometry, printing and coating processes, and raindrops in thunderclouds. Currently, there exist conflicting theories and measurements on the size and charge of these small electrospray droplets. We use theory and simulation to show that conductivity can be tuned to yield three scaling regimes for droplet radius and charge, a finding missed by previous studies. The amount of charge that electrospray droplets carry determines whether they are coulombically stable and charged below the Rayleigh limit of stability or are unstable and hence prone to further explosions once they are formed. Previous experiments reported droplet charge values ranging from 10% to in excess of . Simulations unequivocally show that electrospray droplets are coulombically stable at the instant they are created and that there exists a universal scaling law for droplet charge, . PMID:23487744

  11. Enhanced electrohydrodynamic force generation in a two-stroke cycle dielectric-barrier-discharge plasma actuator

    NASA Astrophysics Data System (ADS)

    Sato, Shintaro; Takahashi, Masayuki; Ohnishi, Naofumi

    2017-05-01

    An approach for electrohydrodynamic (EHD) force production is proposed with a focus on a charge cycle on a dielectric surface. The cycle, consisting of positive-charging and neutralizing strokes, is completely different from the conventional methodology, which involves a negative-charging stroke, in that the dielectric surface charge is constantly positive. The two-stroke charge cycle is realized by applying a DC voltage combined with repetitive pulses. Simulation results indicate that the negative pulse eliminates the surface charge accumulated during constant voltage phase, resulting in repetitive EHD force generation. The time-averaged EHD force increases almost linearly with increasing repetitive pulse frequency and becomes one order of magnitude larger than that driven by the sinusoidal voltage, which has the same peak-to-peak voltage.

  12. The role of amino acids in hydroxyapatite mineralization

    PubMed Central

    2016-01-01

    Polar and charged amino acids (AAs) are heavily expressed in non-collagenous proteins (NCPs), and are involved in hydroxyapatite (HA) mineralization in bone. Here, we review what is known on the effect of single AAs on HA precipitation. Negatively charged AAs, such as aspartic acid, glutamic acid (Glu) and phosphoserine are largely expressed in NCPs and play a critical role in controlling HA nucleation and growth. Positively charged ones such as arginine (Arg) or lysine (Lys) are heavily involved in HA nucleation within extracellular matrix proteins such as collagen. Glu, Arg and Lys intake can also increase bone mineral density by stimulating growth hormone production. In vitro studies suggest that the role of AAs in controlling HA precipitation is affected by their mobility. While dissolved AAs are able to inhibit HA precipitation and growth by chelating Ca2+ and PO43− ions or binding to nuclei of calcium phosphate and preventing their further growth, AAs bound to surfaces can promote HA precipitation by attracting Ca2+ and PO43− ions and increasing the local supersaturation. Overall, the effect of AAs on HA precipitation is worth being investigated more, especially under conditions closer to the physiological ones, where the presence of other factors such as collagen, mineralization inhibitors, and cells heavily influences HA precipitation. A deeper understanding of the role of AAs in HA mineralization will increase our fundamental knowledge related to bone formation, and could lead to new therapies to improve bone regeneration in damaged tissues or cure pathological diseases caused by excessive mineralization in tissues such as cartilage, blood vessels and cardiac valves. PMID:27707904

  13. Optical pumping of the electronic and nuclear spin of single charge-tunable quantum dots.

    PubMed

    Bracker, A S; Stinaff, E A; Gammon, D; Ware, M E; Tischler, J G; Shabaev, A; Efros, Al L; Park, D; Gershoni, D; Korenev, V L; Merkulov, I A

    2005-02-04

    We present a comprehensive examination of optical pumping of spins in individual GaAs quantum dots as we change the net charge from positive to neutral to negative with a charge-tunable heterostructure. Negative photoluminescence polarization memory is enhanced by optical pumping of ground state electron spins, which we prove with the first measurements of the Hanle effect on an individual quantum dot. We use the Overhauser effect in a high longitudinal magnetic field to demonstrate efficient optical pumping of nuclear spins for all three charge states of the quantum dot.

  14. Optical Pumping of the Electronic and Nuclear Spin of Single Charge-Tunable Quantum Dots

    NASA Astrophysics Data System (ADS)

    Bracker, A. S.; Stinaff, E. A.; Gammon, D.; Ware, M. E.; Tischler, J. G.; Shabaev, A.; Efros, Al. L.; Park, D.; Gershoni, D.; Korenev, V. L.; Merkulov, I. A.

    2005-02-01

    We present a comprehensive examination of optical pumping of spins in individual GaAs quantum dots as we change the net charge from positive to neutral to negative with a charge-tunable heterostructure. Negative photoluminescence polarization memory is enhanced by optical pumping of ground state electron spins, which we prove with the first measurements of the Hanle effect on an individual quantum dot. We use the Overhauser effect in a high longitudinal magnetic field to demonstrate efficient optical pumping of nuclear spins for all three charge states of the quantum dot.

  15. Oxygen redox chemistry without excess alkali-metal ions in Na2/3[Mg0.28Mn0.72]O2.

    PubMed

    Maitra, Urmimala; House, Robert A; Somerville, James W; Tapia-Ruiz, Nuria; Lozano, Juan G; Guerrini, Niccoló; Hao, Rong; Luo, Kun; Jin, Liyu; Pérez-Osorio, Miguel A; Massel, Felix; Pickup, David M; Ramos, Silvia; Lu, Xingye; McNally, Daniel E; Chadwick, Alan V; Giustino, Feliciano; Schmitt, Thorsten; Duda, Laurent C; Roberts, Matthew R; Bruce, Peter G

    2018-03-01

    The search for improved energy-storage materials has revealed Li- and Na-rich intercalation compounds as promising high-capacity cathodes. They exhibit capacities in excess of what would be expected from alkali-ion removal/reinsertion and charge compensation by transition-metal (TM) ions. The additional capacity is provided through charge compensation by oxygen redox chemistry and some oxygen loss. It has been reported previously that oxygen redox occurs in O 2p orbitals that interact with alkali ions in the TM and alkali-ion layers (that is, oxygen redox occurs in compounds containing Li + -O(2p)-Li + interactions). Na 2/3 [Mg 0.28 Mn 0.72 ]O 2 exhibits an excess capacity and here we show that this is caused by oxygen redox, even though Mg 2+ resides in the TM layers rather than alkali-metal (AM) ions, which demonstrates that excess AM ions are not required to activate oxygen redox. We also show that, unlike the alkali-rich compounds, Na 2/3 [Mg 0.28 Mn 0.72 ]O 2 does not lose oxygen. The extraction of alkali ions from the alkali and TM layers in the alkali-rich compounds results in severely underbonded oxygen, which promotes oxygen loss, whereas Mg 2+ remains in Na 2/3 [Mg 0.28 Mn 0.72 ]O 2 , which stabilizes oxygen.

  16. Oxygen redox chemistry without excess alkali-metal ions in Na2/3[Mg0.28Mn0.72]O2

    NASA Astrophysics Data System (ADS)

    Maitra, Urmimala; House, Robert A.; Somerville, James W.; Tapia-Ruiz, Nuria; Lozano, Juan G.; Guerrini, Niccoló; Hao, Rong; Luo, Kun; Jin, Liyu; Pérez-Osorio, Miguel A.; Massel, Felix; Pickup, David M.; Ramos, Silvia; Lu, Xingye; McNally, Daniel E.; Chadwick, Alan V.; Giustino, Feliciano; Schmitt, Thorsten; Duda, Laurent C.; Roberts, Matthew R.; Bruce, Peter G.

    2018-03-01

    The search for improved energy-storage materials has revealed Li- and Na-rich intercalation compounds as promising high-capacity cathodes. They exhibit capacities in excess of what would be expected from alkali-ion removal/reinsertion and charge compensation by transition-metal (TM) ions. The additional capacity is provided through charge compensation by oxygen redox chemistry and some oxygen loss. It has been reported previously that oxygen redox occurs in O 2p orbitals that interact with alkali ions in the TM and alkali-ion layers (that is, oxygen redox occurs in compounds containing Li+-O(2p)-Li+ interactions). Na2/3[Mg0.28Mn0.72]O2 exhibits an excess capacity and here we show that this is caused by oxygen redox, even though Mg2+ resides in the TM layers rather than alkali-metal (AM) ions, which demonstrates that excess AM ions are not required to activate oxygen redox. We also show that, unlike the alkali-rich compounds, Na2/3[Mg0.28Mn0.72]O2 does not lose oxygen. The extraction of alkali ions from the alkali and TM layers in the alkali-rich compounds results in severely underbonded oxygen, which promotes oxygen loss, whereas Mg2+ remains in Na2/3[Mg0.28Mn0.72]O2, which stabilizes oxygen.

  17. High-Performance CH3NH3PbI3-Inverted Planar Perovskite Solar Cells with Fill Factor Over 83% via Excess Organic/Inorganic Halide.

    PubMed

    Jahandar, Muhammad; Khan, Nasir; Lee, Hang Ken; Lee, Sang Kyu; Shin, Won Suk; Lee, Jong-Cheol; Song, Chang Eun; Moon, Sang-Jin

    2017-10-18

    The reduction of charge carrier recombination and intrinsic defect density in organic-inorganic halide perovskite absorber materials is a prerequisite to achieving high-performance perovskite solar cells with good efficiency and stability. Here, we fabricated inverted planar perovskite solar cells by incorporation of a small amount of excess organic/inorganic halide (methylammonium iodide (CH 3 NH 3 I; MAI), formamidinium iodide (CH(NH 2 ) 2 I; FAI), and cesium iodide (CsI)) in CH 3 NH 3 PbI 3 perovskite film. Larger crystalline grains and enhanced crystallinity in CH 3 NH 3 PbI 3 perovskite films with excess organic/inorganic halide reduce the charge carrier recombination and defect density, leading to enhanced device efficiency (MAI+: 14.49 ± 0.30%, FAI+: 16.22 ± 0.38% and CsI+: 17.52 ± 0.56%) compared to the efficiency of a control MAPbI 3 device (MAI: 12.63 ± 0.64%) and device stability. Especially, the incorporation of a small amount of excess CsI in MAPbI 3 perovskite film leads to a highly reproducible fill factor of over 83%, increased open-circuit voltage (from 0.946 to 1.042 V), and short-circuit current density (from 18.43 to 20.89 mA/cm 2 ).

  18. Comparing the Effects of Negative and Mixed Emotional Messages on Predicted Occasional Excessive Drinking

    PubMed Central

    Carrera, Pilar; Caballero, Amparo; Muñoz, Dolores

    2008-01-01

    In this work we present two types of emotional message, negative (sadness) versus mixed (joy and sadness), with the aim of studying their differential effect on attitude change and the probability estimated by participants of repeating the behavior of occasional excessive drinking in the near future. The results show that for the group of participants with moderate experience in this behavior the negative message, compared to the mixed one, is associated with higher probability of repeating the risk behavior and a less negative attitude toward it. These results suggest that mixed emotional messages (e.g. joy and sadness messages) could be more effective in campaigns for the prevention of this risk behavior. PMID:25977606

  19. SH3-like motif-containing C-terminal domain of staphylococcal teichoic acid transporter suggests possible function.

    PubMed

    Ko, Tzu-Ping; Tseng, Shih-Ting; Lai, Shu-Jung; Chen, Sheng-Chia; Guan, Hong-Hsiang; Shin Yang, Chia; Jung Chen, Chun; Chen, Yeh

    2016-09-01

    The negatively charged bacterial polysaccharides-wall teichoic acids (WTAs) are synthesized intracellularly and exported by a two-component transporter, TagGH, comprising a transmembrane subunit TagG and an ATPase subunit TagH. We determined the crystal structure of the C-terminal domain of TagH (TagH-C) to investigate its function. The structure shows an N-terminal SH3-like subdomain wrapped by a C-terminal subdomain with an anti-parallel β-sheet and an outer shell of α-helices. A stretch of positively charged surface across the subdomain interface is flanked by two negatively charged regions, suggesting a potential binding site for negatively charged polymers, such as WTAs or acidic peptide chains. Proteins 2016; 84:1328-1332. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

  20. Negative space charge effects in photon-enhanced thermionic emission solar converters

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Segev, G.; Weisman, D.; Rosenwaks, Y.

    2015-07-06

    In thermionic energy converters, electrons in the gap between electrodes form a negative space charge and inhibit the emission of additional electrons, causing a significant reduction in conversion efficiency. However, in Photon Enhanced Thermionic Emission (PETE) solar energy converters, electrons that are reflected by the electric field in the gap return to the cathode with energy above the conduction band minimum. These electrons first occupy the conduction band from which they can be reemitted. This form of electron recycling makes PETE converters less susceptible to negative space charge loss. While the negative space charge effect was studied extensively in thermionicmore » converters, modeling its effect in PETE converters does not account for important issues such as this form of electron recycling, nor the cathode thermal energy balance. Here, we investigate the space charge effect in PETE solar converters accounting for electron recycling, with full coupling of the cathode and gap models, and addressing conservation of both electric and thermal energy. The analysis shows that the negative space charge loss is lower than previously reported, allowing somewhat larger gaps compared to previous predictions. For a converter with a specific gap, there is an optimal solar flux concentration. The optimal solar flux concentration, the cathode temperature, and the efficiency all increase with smaller gaps. For example, for a gap of 3 μm the maximum efficiency is 38% and the optimal flux concentration is 628, while for a gap of 5 μm the maximum efficiency is 31% and optimal flux concentration is 163.« less

  1. Determining the maximum charging currents of lithium-ion cells for small charge quantities

    NASA Astrophysics Data System (ADS)

    Grimsmann, F.; Gerbert, T.; Brauchle, F.; Gruhle, A.; Parisi, J.; Knipper, M.

    2017-10-01

    In order to optimize the operating parameters of battery management systems for electric and hybrid vehicles, great interest has been shown in achieving the maximum permissible charging currents during recuperation, without causing a cell damage due to lithium plating, in relation to the temperature, charge quantity and state of charge. One method for determining these recuperation currents is measuring the cell thickness, where excessively high charging currents can be detected by an irreversible increase in thickness. It is not possible to measure particularly small charge quantities by employing mechanic dial indicators, which have a limited resolution of 1 μm. This is why we developed a measuring setup that has a resolution limit of less than 10 nm using a high-resolution contactless inductance sensor. Our results show that the permissible charging current I can be approximated in relation to the charge quantity x by a correlating function I =a /√{(x) } which is compliant with the Arrhenius law. Small charge quantities therefore have an optimization potential for energy recovery during recuperation.

  2. Scrutinizing data helps team target high-cost DRGs, improve costly tracheostomy care.

    PubMed

    1997-10-01

    Targeting high-cost DRGs using data collection, analysis: A hospital team analyzed DRGs with the highest excess charges and found DRG 483 (tracheostomy) had astronomical charges. Here's the step-by-step story of how they analyzed individual physician resource utilization, care progression through the hospital, and admission source to identify areas for clinical improvement, plus their findings and how they're putting them to use to improve care and reduce costs.

  3. Enhancing biocompatibility of D-oligopeptide hydrogels by negative charges.

    PubMed

    Hyland, Laura L; Twomey, Julianne D; Vogel, Savannah; Hsieh, Adam H; Yu, Y Bruce

    2013-02-11

    Oligopeptide hydrogels are emerging as useful matrices for cell culture with commercial products on the market, but L-oligopeptides are labile to proteases. An obvious solution is to create D-oligopeptide hydrogels, which lack enzymatic recognition. However, D-oligopeptide matrices do not support cell growth as well as L-oligopeptide matrices. In addition to chiral interactions, many cellular activities are strongly governed by charge-charge interactions. In this work, the effects of chirality and charge on human mesenchymal stem cell (hMSC) behavior were studied using hydrogels assembled from oppositely charged oligopeptides. It was found that negative charges significantly improved hMSC viability and proliferation in D-oligopeptide gels but had little effect on their interactions with L-oligopeptide gels. This result points to the possibility of using charge and other factors to engineer biomaterials whose chirality is distinct from that of natural biomaterials, but whose performance is close to that of natural biomaterials.

  4. Influence of humic acid concentration on nTiO2 attachment to quartz sand and Fe-coated quartz sand

    NASA Astrophysics Data System (ADS)

    Cheng, T.; Wu, Y.

    2016-12-01

    The transport of nano-scale or micro-scale titanium dioxide particles (nTiO2) in subsurface environments are strongly influenced by nTiO2 attachment to sediment grains. The objective of this study is to investigate the role of humic acid (HA) in the attachment of nTiO2 to sand at low HA concentrations that are relevant to typical groundwater conditions, so that mechanisms that control nTiO2 immobilization and transport in groundwater can be elucidated. nTiO2 may carry either positive or negative charges in natural water, therefore, environmental factors such as pH, humic substances, and Fe oxyhydroxide coatings on sediment grains, which are known to control the transport of negatively-charged colloids, may influence nTiO2 in different manners. Attachment of nTiO2 to quartz sand and Fe oxyhydroxide coated quartz sand are experimentally measured under a range of HA concentrations at fixed pH. Experimental results show that at pH 5, negatively-charged HA strongly adsorbs to positively-charged nTiO2 and Fe oxyhydroxide, which, at low HA concentrations, partially neutralizes the positive charges on nTiO2 and Fe oxyhydroxide, and therefore decreases the repulsive electrostatic forces between the surfaces, resulting in relatively high nTiO2 attachment. At high HA concentrations, adsorbed HA reverses the surface charges of nTiO2 and Fe oxyhydroxide, and makes nTiO2 and Fe oxyhydroxide strongly negatively charged, resulting in low nTiO2 attachment. At pH 9, HA, nTiO2, and Fe oxyhydroxide are all negatively charged, and HA adsorption is low and does not have a strong impact on the attachment of nTiO2. This study demonstrates that the changes in surface charges of nTiO2 and Fe oxyhydroxide coating caused by HA adsorption could be a key factor that controls the attachment of nTiO2 to sediment grains.

  5. Family bonding and adolescent alcohol use: moderating effect of living with excessive drinking parents.

    PubMed

    Kuendig, Hervé; Kuntsche, Emmanuel

    2006-01-01

    Excessive parental drinking has been shown to be positively related to adolescent alcohol use and family bonding negatively related. The aim of the present study was to determine if the perception of parental drinking moderates the relationship between family bonding and adolescent alcohol use. Linear structural equation models for multiple group comparisons were estimated based on a national representative sample of 3,448 eight and ninth graders in Switzerland (mean age 14.77; SD 0.89). Adjusted for gender and age, the results confirm that strong family bonds were negatively related to both frequency of alcohol intake and lifetime frequency of drunkenness. Furthermore, a positive link was found with regard to the perception of parental drinking. However, the multiple group comparison revealed that the negative relationship between bonding and adolescent alcohol use was even stronger among adolescents whose parents drink excessively than among those whose parents did not. These results indicate that it may be particularly important for parents in the former category to establish strong family bonds (e.g. by spending free time with their children, listening to their worries) so as to limit adolescent excessive drinking.

  6. Prevalence and determinants of overweight and obesity in old age in Germany.

    PubMed

    Hajek, André; Lehnert, Thomas; Ernst, Annette; Lange, Carolin; Wiese, Birgitt; Prokein, Jana; Weyerer, Siegfried; Werle, Jochen; Pentzek, Michael; Fuchs, Angela; Luck, Tobias; Bickel, Horst; Mösch, Edelgard; Heser, Kathrin; Wagner, Michael; Maier, Wolfgang; Scherer, Martin; Riedel-Heller, Steffi G; König, Hans-Helmut

    2015-07-14

    Mean body weight gradually increases with age. Yet, little data exists on the prevalence of excess weight in populations aged 80 years or older. Moreover, little is known about predictors of overweight and obesity in old age. Thus, the purpose of this study was: To present data on the prevalence of excess weight in old age in Germany, to investigate predictors of excess weight in a cross-sectional approach and to examine factors affecting excess weight in a longitudinal approach. Subjects consisted of 1,882 individuals aged 79 years or older. The course of excess weight was observed over 3 years. Excess weight was defined as follows: Overweight (25 kg/m(2) ≤ BMI < 30 kg/m(2)) and obesity (BMI ≥ 30 kg/m(2)). We used fixed effects regressions to estimate effects of time dependent variables on BMI, and overweight or obesity, respectively. The majority was overweight (40.0%) or obese (13.7%). Cross-sectional regressions revealed that BMI was positively associated with younger age, severe walking impairments and negatively associated with cognitive impairments. Excess weight was positively associated with younger age, elementary education, walking impairments and physical inactivity, while excess weight was negatively associated with cognitive impairment. Longitudinal regressions showed that age and severely impaired walking disabilities reduced BMI. The probability of transitions to excess weight decreased considerably with older age and occurrence of severe walking impairments (overweight). Marked differences between predictors in cross- and longitudinal setting exist, underlining the complex nature of excess weight in old age.

  7. Effects of different blasting materials on charge generation and decay on titanium surface after sandblasting.

    PubMed

    Guo, Cecilia Yan; Hong Tang, Alexander Tin; Hon Tsoi, James Kit; Matinlinna, Jukka Pekka

    2014-04-01

    It has been reported that sandblasting titanium with alumina (Al2O3) powder could generate a negative electric charge on titanium surface. This has been proven to promote osteoblast activities and possibly osseointegration. The purpose of this pilot study was to investigate the effects of different blasting materials, in terms of the grit sizes and electro-negativity, on the generation of a negative charge on the titanium surface. The aim was also to make use of these results to deduct the underlying mechanism of charge generation by sandblasting. Together 60 c.p. 2 titanium plates were machine-cut and polished for sandblasting, and divided into 6 groups with 10 plates in each. Every plate in the study groups was sandblasted with one of the following 6 powder materials: 110µm Al2O3 grits, 50µm Al2O3 grits, 150-300µm glass beads, 45-75µm glass beads, 250µm Al powder and 44µm Al powder. The static voltage on the surface of every titanium plate was measured immediately after sandblasting. The static voltages of the titanium plates were recorded and processed using statistical analysis. The results suggested that only sandblasting with 45-75µm glass beads generated a positive charge on titanium, while using all other blasting materials lead to a negative charge. Furthermore, blasting grits of the same powder material but of different sizes might lead to different amount and polarity of the charges. This triboelectric effect is likely to be the main mechanism for charge generation through sandblasting. Copyright © 2014 Elsevier Ltd. All rights reserved.

  8. Lipids and topological rules of membrane protein assembly: balance between long and short range lipid-protein interactions.

    PubMed

    Vitrac, Heidi; Bogdanov, Mikhail; Heacock, Phil; Dowhan, William

    2011-04-29

    The N-terminal six-transmembrane domain (TM) bundle of lactose permease of Escherichia coli is uniformly inverted when assembled in membranes lacking phosphatidylethanolamine (PE). Inversion is dependent on the net charge of cytoplasmically exposed protein domains containing positive and negative residues, net charge of the membrane surface, and low hydrophobicity of TM VII acting as a molecular hinge between the two halves of lactose permease (Bogdanov, M., Xie, J., Heacock, P., and Dowhan, W. (2008) J. Cell Biol. 182, 925-935). Net neutral lipids suppress the membrane translocation potential of negatively charged amino acids, thus increasing the cytoplasmic retention potential of positively charged amino acids. Herein, TM organization of sucrose permease (CscB) and phenylalanine permease (PheP) as a function of membrane lipid composition was investigated to extend these principles to other proteins. For CscB, topological dependence on PE only becomes evident after a significant increase in the net negative charge of the cytoplasmic surface of the N-terminal TM bundle. High negative charge is required to overcome the thermodynamic block to inversion due to the high hydrophobicity of TM VII. Increasing the positive charge of the cytoplasmic surface of the N-terminal TM hairpin of PheP, which is misoriented in PE-lacking cells, favors native orientation in the absence of PE. PheP and CscB also display co-existing dual topologies dependent on changes in the charge balance between protein domains and the membrane lipids. Therefore, the topology of both permeases is dependent on PE. However, CscB topology is governed by thermodynamic balance between opposing lipid-dependent electrostatic and hydrophobic interactions.

  9. Structural Transformation of Li-Excess Cathode Materials via Facile Preparation and Assembly of Sonication-Induced Colloidal Nanocrystals for Enhanced Lithium Storage Performance.

    PubMed

    Zhao, Jianqing; Huang, Ruiming; Ramos, Pablo; Yue, Yiying; Wu, Qinglin; Pavanello, Michele; Zhou, Jieyu; Kuai, Xiaoxiao; Gao, Lijun; He, Huixin; Wang, Ying

    2017-09-13

    A surfactant-free sonication-induced route is developed to facilely prepare colloidal nanocrystals of Li-excess layered Li 1.2 Mn 0.54 Ni 0.13 Co 0.13 O 2 (marked as LMNCO) material. The sonication process plays a critical role in forming LMNCO nanocrystals in ethanol (ethanol molecules marked as EtOHs) and inducing the interaction between LMNCO and solvent molecules. The formation mechanism of LMNCO-EtOH supramolecules in the colloidal dispersion system is proposed and examined by the theoretical simulation and light scattering technique. It is suggested that the as-formed supramolecule is composed of numerous ethanol molecules capping the surface of the LMNCO nanocrystal core via hydrogen bonding. Such chemisorption gives rise to dielectric polarization of the absorbed ethanol molecules, resulting in a negative surface charge of LMNCO colloids. The self-assembly behaviors of colloidal LMNCO nanocrystals are then tentatively investigated by tuning the solvent evaporation condition, which results in diverse superstructures of LMNCO materials after the evaporation of ethanol. The reassembled LMNCO architectures exhibit remarkably improved capacity and cyclability in comparison with the original LMNCO particles, demonstrating a very promising cathode material for high-energy lithium-ion batteries. This work thus provides new insights into the formation and self-assembly of multiple-element complex inorganic colloids in common and surfactant-free solvents for enhanced performance in device applications.

  10. Dynamics of two-dimensional monolayer water confined in hydrophobic and charged environments.

    PubMed

    Kumar, Pradeep; Han, Sungho

    2012-09-21

    We perform molecular dynamics simulations to study the effect of charged surfaces on the intermediate and long time dynamics of water in nanoconfinements. Here, we use the transferable interaction potential with five points (TIP5P) model of a water molecule confined in both hydrophobic and charged surfaces. For a single molecular layer of water between the surfaces, we find that the temperature dependence of the lateral diffusion constant of water up to very high temperatures remains Arrhenius with a high activation energy. In case of charged surfaces, however, the dynamics of water in the intermediate time regime is drastically modified presumably due to the transient coupling of dipoles of water molecules with electric field fluctuations induced by charges on the confining surfaces. Specifically, the lateral mean square displacements display a distinct super-diffusive behavior at intermediate time scale, defined as the time scale between ballistic and diffusive regimes. This change in the intermediate time-scale dynamics in the charged confinement leads to the enhancement of long-time dynamics as reflected in increasing diffusion constant. We introduce a simple model for a possible explanation of the super-diffusive behavior and find it to be in good agreement with our simulation results. Furthermore, we find that confinement and the surface polarity enhance the low frequency vibration in confinement compared to bulk water. By introducing a new effective length scale of coupling between translational and orientational motions, we find that the length scale increases with the increasing strength of the surface polarity. Further, we calculate the correlation between the diffusion constant and the excess entropy and find a disordering effect of polar surfaces on the structure of water. Finally, we find that the empirical relation between the diffusion constant and the excess entropy holds for a monolayer of water in nanoconfinement.

  11. The electrokinetic behavior of calcium oxalate monohydrate in macromolecular solutions

    NASA Technical Reports Server (NTRS)

    Curreri, P. A.; Onoda, G. Y., Jr.; Finlayson, B.

    1988-01-01

    Electrophoretic mobilities were measured for calcium oxalate monohydrate (COM) in solutions containing macromolecules. Two mucopolysaccharides (sodium heparin and chrondroitin sulfate) and two proteins (positively charged lysozyme and negatively charged bovine serum albumin) were studied as adsorbates. The effects of pH, calcium oxalate surface charge (varied by calcium or oxalate ion activity), and citrate concentration were investigated. All four macromolecules showed evidence for chemical adsorption. The macromolecule concentrations needed for reversing the surface charge indicated that the mucopopolysacchrides have greater affinity for the COM surface than the proteins. The amount of proteins that can chemically adsorb appears to be limited to approximately one monomolecular layer. When the surface charge is high, an insufficient number of proteins can chemically adsorb to neutralize or reverse the surface charge. The remaining surface charge is balanced by proteins held near the surface by longer range electrostatic forces only. Citrate ions at high concentrations appear to compete effectively with the negative protein for surface sites but show no evidence for competing with the positively charged protein.

  12. Analysis of microscopic parameters of surface charging in polymer caused by defocused electron beam irradiation.

    PubMed

    Liu, Jing; Zhang, Hai-Bo

    2014-12-01

    The relationship between microscopic parameters and polymer charging caused by defocused electron beam irradiation is investigated using a dynamic scattering-transport model. The dynamic charging process of an irradiated polymer using a defocused 30 keV electron beam is conducted. In this study, the space charge distribution with a 30 keV non-penetrating e-beam is negative and supported by some existing experimental data. The internal potential is negative, but relatively high near the surface, and it decreases to a maximum negative value at z=6 μm and finally tend to 0 at the bottom of film. The leakage current and the surface potential behave similarly, and the secondary electron and leakage currents follow the charging equilibrium condition. The surface potential decreases with increasing beam current density, trap concentration, capture cross section, film thickness and electron-hole recombination rate, but with decreasing electron mobility and electron energy. The total charge density increases with increasing beam current density, trap concentration, capture cross section, film thickness and electron-hole recombination rate, but with decreasing electron mobility and electron energy. This study shows a comprehensive analysis of microscopic factors of surface charging characteristics in an electron-based surface microscopy and analysis. Copyright © 2014 Elsevier Ltd. All rights reserved.

  13. Charge Segregation and Low Hydrophobicity Are Key Features of Ribosomal Proteins from Different Organisms*

    PubMed Central

    Fedyukina, Daria V.; Jennaro, Theodore S.; Cavagnero, Silvia

    2014-01-01

    Ribosomes are large and highly charged macromolecular complexes consisting of RNA and proteins. Here, we address the electrostatic and nonpolar properties of ribosomal proteins that are important for ribosome assembly and interaction with other cellular components and may influence protein folding on the ribosome. We examined 50 S ribosomal subunits from 10 species and found a clear distinction between the net charge of ribosomal proteins from halophilic and non-halophilic organisms. We found that ∼67% ribosomal proteins from halophiles are negatively charged, whereas only up to ∼15% of ribosomal proteins from non-halophiles share this property. Conversely, hydrophobicity tends to be lower for ribosomal proteins from halophiles than for the corresponding proteins from non-halophiles. Importantly, the surface electrostatic potential of ribosomal proteins from all organisms, especially halophiles, has distinct positive and negative regions across all the examined species. Positively and negatively charged residues of ribosomal proteins tend to be clustered in buried and solvent-exposed regions, respectively. Hence, the majority of ribosomal proteins is characterized by a significant degree of intramolecular charge segregation, regardless of the organism of origin. This key property enables the ribosome to accommodate proteins within its complex scaffold regardless of their overall net charge. PMID:24398678

  14. Molecular and phenotypic aspects of CHD7 mutation in CHARGE syndrome

    PubMed Central

    Zentner, Gabriel E.; Layman, Wanda S.; Martin, Donna M.; Scacheri, Peter C.

    2010-01-01

    CHARGE syndrome (Coloboma of the eye, Heart defects, Atresia of the choanae, Retardation of growth and/or development, Genital and/or urinary abnormalities, and Ear abnormalities (including deafness) is a genetic disorder characterized by a specific and a recognizable pattern of anomalies. De novo mutations in the gene encoding chromodomain helicase DNA binding protein 7 (CHD7) are the major cause of CHARGE syndrome. Here, we review the clinical features of 379 CHARGE patients who tested positive or negative for mutations in CHD7. We found that CHARGE individuals with CHD7 mutations more commonly have ocular colobomas, temporal bone anomalies (semicircular canal hypoplasia/dysplasia), and facial nerve paralysis compared with mutation negative individuals. We also highlight recent genetic and genomic studies that have provided functional insights into CHD7 and the pathogenesis of CHARGE syndrome. PMID:20186815

  15. Effect of Fe{sub 3}O{sub 4} nanoparticles on space charge distribution in propylene carbonate under impulse voltage

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Sima, Wenxia, E-mail: cqsmwx@cqu.edu.cn; Song, He; Yang, Qing

    2015-12-15

    Addition of nanoparticles of the ferromagnetic material Fe{sub 3}O{sub 4} can increase the positive impulse breakdown voltage of propylene carbonate by 11.65%. To further investigate the effect of ferromagnetic nanoparticles on the space charge distribution in the discharge process, the present work set up a Kerr electro-optic field mapping measurement system using an array photodetector to carry out time-continuous measurement of the electric field and space charge distribution in propylene carbonate before and after modification. Test results show that fast electrons can be captured by Fe{sub 3}O{sub 4} nanoparticles and converted into relatively slow, negatively charged particles, inhibiting the generationmore » and transportation of the space charge, especially the negative space charge.« less

  16. DOE Office of Scientific and Technical Information (OSTI.GOV)

    Duan, Yandong; Zhang, Bingkai; Zheng, Jiaxin

    Abstract. Due to the enhanced kinetic properties, nanocrystallites have received much attention as potential electrode materials for energy storage. However, because of the large specific surface areas of nanocrystallites, they usually suffer from decreased energy density, reduced cycling stability and total electrode capacity. In this work, we report a size-dependent excess capacity beyond the theoretical value of 170 mAhg-1 in a special carbon coated LiFePO4 composite cathode material, which delivers capacities of 191.2 and 213.5 mAhg-1 with the mean particle sizes of 83 nm and 42 nm, respectively. Moreover, this LiFePO4 composite also shows excellent cycling stability and high ratemore » performance. Our further experimental tests and ab initio calculations reveal that the excess capacity comes from the charge passivation for which the C-O-Fe bonds would lead to charge redistribution on the surface of LiFePO4 and hence to enhance the bonding interaction between surface O atoms and Li-ions. The surface reconstruction for excess Li-ion storage makes full use of the large specific surface area for the nanocrystallites, which can maintain the fast Li-ion transport and enhance the capacity greatly that the nanocrystallites usually suffers.« less

  17. Modeling of plug-in electric vehicle travel patterns and charging load based on trip chain generation

    NASA Astrophysics Data System (ADS)

    Wang, Dai; Gao, Junyu; Li, Pan; Wang, Bin; Zhang, Cong; Saxena, Samveg

    2017-08-01

    Modeling PEV travel and charging behavior is the key to estimate the charging demand and further explore the potential of providing grid services. This paper presents a stochastic simulation methodology to generate itineraries and charging load profiles for a population of PEVs based on real-world vehicle driving data. In order to describe the sequence of daily travel activities, we use the trip chain model which contains the detailed information of each trip, namely start time, end time, trip distance, start location and end location. A trip chain generation method is developed based on the Naive Bayes model to generate a large number of trips which are temporally and spatially coupled. We apply the proposed methodology to investigate the multi-location charging loads in three different scenarios. Simulation results show that home charging can meet the energy demand of the majority of PEVs in an average condition. In addition, we calculate the lower bound of charging load peak on the premise of lowest charging cost. The results are instructive for the design and construction of charging facilities to avoid excessive infrastructure.

  18. Lifetime of excess electrons in Cu–Zn–Sn–Se powders

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Novikov, G. F., E-mail: ngf@icp.ac.ru; Gapanovich, M. V.; Gremenok, V. F.

    2017-01-15

    The method of time-resolved microwave photoconductivity at a frequency of 36 GHz in the range of temperatures of 200–300 K is used to study the kinetics of the annihilation of charge carriers in Cu–Zn–Sn–Se powders obtained by the solid-phase method of synthesis in cells. The lifetime of excess electrons at room temperature is found to be shorter than 5 ns. The activation energy for the process of recombination amounted to E{sub a} ~ 0.054 eV.

  19. Tunneling modulation of a quantum-well transistor laser

    NASA Astrophysics Data System (ADS)

    Feng, M.; Qiu, J.; Wang, C. Y.; Holonyak, N.

    2016-11-01

    Different than the Bardeen and Brattain transistor (1947) with the current gain depending on the ratio of the base carrier spontaneous recombination lifetime to the emitter-collector transit time, the Feng and Holonyak transistor laser current gain depends upon the base electron-hole (e-h) stimulated recombination, the base dielectric relaxation transport, and the collector stimulated tunneling. For the n-p-n transistor laser tunneling operation, the electron-hole pairs are generated at the collector junction under the influence of intra-cavity photon-assisted tunneling, with electrons drifting to the collector and holes drifting to the base. The excess charge in the base lowers the emitter junction energy barrier, allowing emitter electron injection into the base and satisfying charge neutrality via base dielectric relaxation transport (˜femtoseconds). The excess electrons near the collector junction undergo stimulated recombination at the base quantum-well or transport to the collector, thus supporting tunneling current amplification and optical modulation of the transistor laser.

  20. Response of GaAs charge storage devices to transient ionizing radiation

    NASA Astrophysics Data System (ADS)

    Hetherington, D. L.; Klem, J. F.; Hughes, R. C.; Weaver, H. T.

    Charge storage devices in which non-equilibrium depletion regions represent stored charge are sensitive to ionizing radiation. This results since the radiation generates electron-hole pairs that neutralize excess ionized dopant charge. Silicon structures, such as dynamic RAM or CCD cells are particularly sensitive to radiation since carrier diffusion lengths in this material are often much longer than the depletion width, allowing collection of significant quantities of charge from quasi-neutral sections of the device. For GaAs the situation is somewhat different in that minority carrier diffusion lengths are shorter than in silicon, and although mobilities are higher, we expect a reduction of radiation sensitivity as suggested by observations of reduced quantum efficiency in GaAs solar cells. Dynamic memory cells in GaAs have potential increased retention times. In this paper, we report the response of a novel GaAs dynamic memory element to transient ionizing radiation. The charge readout technique is nondestructive over a reasonable applied voltage range and is more sensitive to stored charge than a simple capacitor.

  1. Charge-Dissipative Electrical Cables

    NASA Technical Reports Server (NTRS)

    Kolasinski, John R.; Wollack, Edward J.

    2004-01-01

    Electrical cables that dissipate spurious static electric charges, in addition to performing their main functions of conducting signals, have been developed. These cables are intended for use in trapped-ion or ionizing-radiation environments, in which electric charges tend to accumulate within, and on the surfaces of, dielectric layers of cables. If the charging rate exceeds the dissipation rate, charges can accumulate in excessive amounts, giving rise to high-current discharges that can damage electronic circuitry and/or systems connected to it. The basic idea of design and operation of charge-dissipative electrical cables is to drain spurious charges to ground by use of lossy (slightly electrically conductive) dielectric layers, possibly in conjunction with drain wires and/or drain shields (see figure). In typical cases, the drain wires and/or drain shields could be electrically grounded via the connector assemblies at the ends of the cables, in any of the conventional techniques for grounding signal conductors and signal shields. In some cases, signal shields could double as drain shields.

  2. The voltage-dependent anion channel as a biological transistor: theoretical considerations.

    PubMed

    Lemeshko, V V; Lemeshko, S V

    2004-07-01

    The voltage-dependent anion channel (VDAC) is a porin of the mitochondrial outer membrane with a bell-shaped permeability-voltage characteristic. This porin restricts the flow of negatively charged metabolites at certain non-zero voltages, and thus might regulate their flux across the mitochondrial outer membrane. Here, we have developed a mathematical model illustrating the possibility of interaction between two steady-state fluxes of negatively charged metabolites circulating across the VDAC in a membrane. The fluxes interact by contributing to generation of the membrane electrical potential with subsequent closure of the VDAC. The model predicts that the VDAC might function as a single-molecule biological transistor and amplifier, because according to the obtained calculations a small change in the flux of one pair of different negatively charged metabolites causes a significant modulation of a more powerful flux of another pair of negatively charged metabolites circulating across the same membrane with the VDAC. Such transistor-like behavior of the VDAC in the mitochondrial outer membrane might be an important principle of the cell energy metabolism regulation under some physiological conditions.

  3. An in situ generated carbon as integrated conductive additive for hierarchical negative plate of lead-acid battery

    NASA Astrophysics Data System (ADS)

    Saravanan, M.; Ganesan, M.; Ambalavanan, S.

    2014-04-01

    In this work, we report an in situ generated carbon from sugar as additive in the Negative Active Mass (NAM) which enhances the charge-discharge characteristics of the lead-acid cells. In situ formed sugar derived carbon (SDC) with leady oxide (LO) provides a conductive network and excellent protection against NAM irreversible lead sulfation. The effect of SDC and carbon black (CB) added negative plates are characterized by X-ray diffraction (XRD), Raman spectroscopy, scanning electron microscopy (SEM), galvanostatic charge-discharge, cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS), respectively. The results show that subtle changes in the addition of carbon to NAM led to subsequent changes on the performance during partial-state-of-charge (PSoC) operations in lead-acid cells. Furthermore, SDC added cells exhibit remarkable improvement in the rate capability, active material utilization, cycle performance and charge acceptance compared to that of the conventional CB added cells. The impact of SDC with LO at various synthesis conditions on the electrochemical performance of the negative plate is studied systematically.

  4. Functionalized nanoparticle interactions with polymeric membranes.

    PubMed

    Ladner, D A; Steele, M; Weir, A; Hristovski, K; Westerhoff, P

    2012-04-15

    A series of experiments was performed to measure the retention of a class of functionalized nanoparticles (NPs) on porous (microfiltration and ultrafiltration) membranes. The findings impact engineered water and wastewater treatment using membrane technology, characterization and analytical schemes for NP detection, and the use of NPs in waste treatment scenarios. The NPs studied were composed of silver, titanium dioxide, and gold; had organic coatings to yield either positive or negative surface charge; and were between 2 and 10nm in diameter. NP solutions were applied to polymeric membranes composed of different materials and pore sizes (ranging from ≈ 2 nm [3 kDa molecular weight cutoff] to 0.2 μm). Greater than 99% rejection was observed of positively charged NPs by negatively charged membranes even though pore diameters were up to 20 times the NP diameter; thus, sorption caused rejection. Negatively charged NPs were less well rejected, but behavior was dependent not only on surface functionality but on NP core material (Ag, TiO(2), or Au). NP rejection depended more upon NP properties than membrane properties; all of the negatively charged polymeric membranes behaved similarly. The NP-membrane interaction behavior fell into four categories, which are defined and described here. Copyright © 2011 Elsevier B.V. All rights reserved.

  5. DOE Office of Scientific and Technical Information (OSTI.GOV)

    Chertkov, Michael; Turitsyn, Konstantin; Sulc, Petr

    The anticipated increase in the number of plug-in electric vehicles (EV) will put additional strain on electrical distribution circuits. Many control schemes have been proposed to control EV charging. Here, we develop control algorithms based on randomized EV charging start times and simple one-way broadcast communication allowing for a time delay between communication events. Using arguments from queuing theory and statistical analysis, we seek to maximize the utilization of excess distribution circuit capacity while keeping the probability of a circuit overload negligible.

  6. Surface charge accumulation of solid insulator under nanosecond pulse in vacuum: 3D distribution features and mechanism

    NASA Astrophysics Data System (ADS)

    Qi, Bo; Gao, Chunjia; Sun, Zelai; Li, Chengrong

    2017-11-01

    Surface charge accumulation can incur changes in electric field distribution, involved in the electron propagation process, and result in a significant decrease in the surface flashover voltage. The existing 2D surface charge measurement fails to meet the actual needs in real engineering applications that usually adopt the 45° conical frustum insulators. The present research developed a novel 3D measurement platform to capture surface charge distribution on solid insulation under nanosecond pulse in a vacuum. The results indicate that all surface charges are positive under a positive pulse and negative under a negative pulse. Surface charges tend to accumulate more near the upper electrode. Surface charge density increases significantly with the increase in pulse counts and amplitudes. Accumulation of surface charge results in a certain decrease of flashover voltage. Taking consideration of the secondary electron emission for the surface charge accumulation, four materials were obtained to demonstrate the effects on surface charge. Combining the effect incurred by secondary electron emission and the weighty action taken by surface charge accumulation on the flashover phenomena, the discharge mechanism along the insulator surface under nanosecond pulse voltage was proposed.

  7. Lightning Activity Relative to the Microphysical and Kinematic Structure of Storms during a Thunder-Snow Episode on 29-30 November 2006

    NASA Astrophysics Data System (ADS)

    Emersic, C.; Macgorman, D.; Schuur, T.; Lund, N.; Payne, C.; Bruning, E.

    2007-12-01

    We have examined lightning activity relative to the microphysical and kinematic structure of a winter thunderstorm complex (a thunder-snow episode) observed east of Norman, Oklahoma during the evening of 29-30 November 2006. Polarimetric radar provided information about the type of particles present in various regions of the storms. The Lightning Mapping Array (LMA) recorded VHF signals produced by developing lightning channels. The times of arrival of these lightning signals across the array were then used to reconstruct the location and structure of lightning, and these reconstructions were overlaid with radar data to examine the relationship between lightning properties and storm particle types. Four storms in this winter complex have been examined. It was inferred from lightning structure that, in their mature stage, all cells we examined had a positive tripole electrical structure (an upper positive charge center, a midlevel negative charge center, and a lower positive charge center). The storms began with lightning activity in the lower dipole (lower positive and midlevel negative regions), but this evolved into lightning activity throughout the tripole structure within approximately 15-20 minutes. In the longer lived storms, the mature stage lasted for approximately 1.5-2 hours. During this stage, the lower positive charge region was situated less than 5 km above ground, the midlevel negative charge region was typically above 5 km, and the upper positive charge region was located at an altitude of less than 10 km in all the storm cells analyzed. The charge regions descended over approximately the last 30 minutes of lightning activity, the lower charge regions eventually reaching ground. This resulted in the loss of the lower positive charge center and the subsequent diminishment of the lower negative charge center. Lightning initiation usually coincided with the edges of regions of high reflectivity and was coincident with the presence of graupel and ice crystals in the lower dipole. Radar data suggest that ice crystals were the dominant charge carriers in the upper positive region.

  8. Lunar Surface Charging during Solar Energetic Particle Events

    NASA Astrophysics Data System (ADS)

    Halekas, Jasper S.; Delory, G. T.; Mewaldt, R. A.; Lin, R. P.; Fillingim, M. O.; Brain, D. A.; Lee, C. O.; Stubbs, T. J.; Farrell, W. M.; Hudson, M. K.

    2006-09-01

    The surface of the Moon, not protected by any substantial atmosphere, is directly exposed to the impact of both solar UV and solar wind plasma and energetic particles. This creates a complex lunar electrostatic environment, with the surface typically charging slightly positive in sunlight, and negative in shadow. Observations from the Apollo era and theoretical considerations strongly suggest that surface charging leads to dust electrification and transport, posing a potentially significant hazard for exploration. The most significant charging effects should occur when the Moon is exposed to high-temperature plasmas like those encountered in the terrestrial plasmasheet or in solar storms. We now present evidence for kilovolt-scale negative charging of the shadowed lunar surface during solar energetic particle (SEP) events, utilizing data from the Lunar Prospector Electron Reflectometer (LP ER). We find that SEP events are associated with the most extreme lunar surface charging observed during the LP mission - rivaled only by previously reported charging during traversals of the terrestrial plasmasheet. The largest charging event observed by LP is a 4 kV negative surface potential (as compared to typical values of V) during a SEP event in May 1998. We characterize lunar surface charging during several SEP events, and compare to energetic particle measurements from ACE, Wind, and SOHO in order to determine the relationship between SEP events and extreme lunar surface charging. Space weather events are already considered by NASA to be a significant hazard to lunar exploration, due to high-energy ionizing radiation. Our observations demonstrate that plasma interactions with the lunar surface during SEP events, causing extreme surface charging and potentially significant dust electrification and transport, represent an additional hazard associated with space weather.

  9. Effect of surface material on electrostatic charging of houseflies (Musca domestica L).

    PubMed

    McGonigle, Daniel F; Jackson, Chris W

    2002-04-01

    Houseflies (Musca domestica L) accumulated electrostatic charges when walking over clean, uncharged dielectric surfaces. The charges elicited on a walking housefly by a range of materials were quantified, allowing a triboelectric series to be determined relative to M domestica. This ranged from surfaces that charged individuals positively, e.g. Correx (corrugated polypropylene) [.1 (+/- 4.2)pC], to those that applied a negative charge, e.g. clear cast acrylic [-14.9 (+/- 2.9)pC]. Maximum positive and negative charges accumulated by individual M domestica were +73 and -27 pC. Replicate measurements on the same fly and surface showed little variation. Variation between individuals was not related to sex and was not consistent between surfaces. Different materials charged M domestica significantly differently and individual flies had significantly different charging properties. Variation in temperature between 21.3 degrees C and 24.7 degrees C and humidity between 24% and 41% RH significantly affected charge accumulated by M domestica on some surfaces, although further experimentation is needed to confirm this. The implications of this work are discussed in relation to insect trap design and pollination biology.

  10. Maxwell's conjecture on three point charges with equal magnitudes

    NASA Astrophysics Data System (ADS)

    Tsai, Ya-Lun

    2015-08-01

    Maxwell's conjecture on three point charges states that the number of non-degenerate equilibrium points of the electrostatic field generated by them in R3 is at most four. We prove the conjecture in the cases when three point charges have equal magnitudes and show the number of isolated equilibrium points can only be zero, two, three, or four. Specifically, fixing positions of two positive charges in R3, we know exactly where to place the third positive charge to have two, three, or four equilibrium points. All equilibrium points are isolated and there are no other possibilities for the number of isolated equilibrium points. On the other hand, if both two of the fixed charges have negative charge values, there are always two equilibrium points except when the third positive charge lies in the line segment connecting the two negative charges. The exception cases are when the field contains only a curve of equilibrium points. In this paper, computations assisted by computer involve symbolic and exact integer computations. Therefore, all the results are proved rigorously.

  11. Unexplained Excess of Electronlike Events from a 1-GeV Neutrino Beam

    NASA Astrophysics Data System (ADS)

    Aguilar-Arevalo, A. A.; Anderson, C. E.; Bazarko, A. O.; Brice, S. J.; Brown, B. C.; Bugel, L.; Cao, J.; Coney, L.; Conrad, J. M.; Cox, D. C.; Curioni, A.; Djurcic, Z.; Finley, D. A.; Fleming, B. T.; Ford, R.; Garcia, F. G.; Garvey, G. T.; Green, C.; Green, J. A.; Hart, T. L.; Hawker, E.; Imlay, R.; Johnson, R. A.; Karagiorgi, G.; Kasper, P.; Katori, T.; Kobilarcik, T.; Kourbanis, I.; Koutsoliotas, S.; Laird, E. M.; Linden, S. K.; Link, J. M.; Liu, Y.; Liu, Y.; Louis, W. C.; Mahn, K. B. M.; Marsh, W.; McGregor, G.; Metcalf, W.; Meyers, P. D.; Mills, F.; Mills, G. B.; Monroe, J.; Moore, C. D.; Nelson, R. H.; Nguyen, V. T.; Nienaber, P.; Nowak, J. A.; Ouedraogo, S.; Patterson, R. B.; Perevalov, D.; Polly, C. C.; Prebys, E.; Raaf, J. L.; Ray, H.; Roe, B. P.; Russell, A. D.; Sandberg, V.; Schirato, R.; Schmitz, D.; Shaevitz, M. H.; Shoemaker, F. C.; Smith, D.; Sodeberg, M.; Sorel, M.; Spentzouris, P.; Stancu, I.; Stefanski, R. J.; Sung, M.; Tanaka, H. A.; Tayloe, R.; Tzanov, M.; van de Water, R.; Wascko, M. O.; White, D. H.; Wilking, M. J.; Yang, H. J.; Zeller, G. P.; Zimmerman, E. D.

    2009-03-01

    The MiniBooNE Collaboration observes unexplained electronlike events in the reconstructed neutrino energy range from 200 to 475 MeV. With 6.46×1020 protons on target, 544 electronlike events are observed in this energy range, compared to an expectation of 415.2±43.4 events, corresponding to an excess of 128.8±20.4±38.3 events. The shape of the excess in several kinematic variables is consistent with being due to either νe and ν¯e charged-current scattering or νμ neutral-current scattering with a photon in the final state. No significant excess of events is observed in the reconstructed neutrino energy range from 475 to 1250 MeV, where 408 events are observed compared to an expectation of 385.9±35.7 events.

  12. DAMPE squib? Significance of the 1.4 TeV DAMPE excess

    NASA Astrophysics Data System (ADS)

    Fowlie, Andrew

    2018-05-01

    We present a Bayesian and frequentist analysis of the DAMPE charged cosmic ray spectrum. The spectrum, by eye, contained a spectral break at about 1TeV and a monochromatic excess at about 1.4TeV. The break was supported by a Bayes factor of about 1010 and we argue that the statistical significance was resounding. We investigated whether we should attribute the excess to dark matter annihilation into electrons in a nearby subhalo. We found a local significance of about 3.6σ and a global significance of about 2.3σ, including a two-dimensional look-elsewhere effect by simulating 1000 pseudo-experiments. The Bayes factor was sensitive to our choices of priors, but favoured the excess by about 2 for our choices. Thus, whilst intriguing, the evidence for a signal is not currently compelling.

  13. Physical Origin of Transient Negative Capacitance in a Ferroelectric Capacitor

    NASA Astrophysics Data System (ADS)

    Chang, Sou-Chi; Avci, Uygar E.; Nikonov, Dmitri E.; Manipatruni, Sasikanth; Young, Ian A.

    2018-01-01

    Transient negative differential capacitance, the dynamic reversal of transient capacitance in an electrical circuit, is of highly technological and scientific interest since it probes the foundation of ferroelectricity. We study a resistor-ferroelectric capacitor (R -FEC) network through a series of coupled equations based on Kirchhoff's law, electrostatics, and Landau theory. We show that transient negative capacitance (NC) in a R -FEC circuit originates from the mismatch in switching rate between the free charge on the metal plate and the bound charge in a ferroelectric (FE) capacitor during the polarization switching. This transient free charge-polarization mismatch is driven by the negative curvature of the FE free-energy landscape, and it is also analytically shown that a free-energy profile with a negative curvature is the only physical system that can describe transient NC in a R -FEC circuit. Furthermore, transient NC induced by the free charge-polarization mismatch is justified by its dependence on both external resistance and the intrinsic FE viscosity coefficient. The depolarization effect on FE capacitors emphasizes the importance of negative curvature to transient NC and also implies that transient and steady-state NC cannot be observed in a FE capacitor simultaneously. Finally, using the transient NC measurements, a procedure to experimentally determine the viscosity coefficient is presented to provide more insight into the relation between transient NC and the FE free-energy profile.

  14. Receptor-Mediated Melanoma Targeting with Radiolabeled α-Melanocyte-Stimulating Hormone: Relevance of the Net Charge of the Ligand.

    PubMed

    Bapst, Jean-Philippe; Eberle, Alex N

    2017-01-01

    A majority of melanotic and amelanotic melanomas overexpress melanocortin type 1 receptors (MC1Rs) for α-melanocyte-stimulating hormone. Radiolabeled linear or cyclic analogs of α-MSH have a great potential as diagnostic or therapeutic tools for the management of malignant melanoma. Compounds such as [ 111 In]DOTA-NAP-amide exhibit high affinity for the MC1R in vitro , good tumor uptake in vivo , but they may suffer from relatively high kidney uptake and retention in vivo . We have shown previously that the introduction of negative charges into radiolabeled DOTA-NAP-amide peptide analogs may enhance their excretion and reduce kidney retention. To address the question of where to place negative charges within the ligand, we have extended these studies by designing two novel peptides, Ac-Nle-Asp-His-d-Phe-Arg-Trp-Gly-Lys(DOTA)-d-Asp-d-Asp-OH (DOTA-NAP-d-Asp-d-Asp) with three negative charges at the C -terminal end (overall net charge of the molecule -2) and DOTA-Gly-Tyr(P)-Nle-Asp-His-d-Phe-Arg-Trp-NH 2 (DOTA-Phospho-MSH 2-9 ) with two negative charges in the N -terminal region (net charge -1). The former peptide showed markedly reduced receptor affinity and biological activity by >10-fold compared to DOTA-NAP-amide as reference compound, and the latter peptide displayed similar bioactivity and receptor affinity as the reference compound. The uptake by melanoma tumor tissue of [ 111 In]DOTA-Phospho-MSH 2-9 was 7.33 ± 0.47 %ID/g 4 h after injection, i.e., almost equally high as with [ 111 In]DOTA-NAP-amide. The kidney retention was 2.68 ± 0.18 %ID/g 4 h after injection and hence 44% lower than that of [ 111 In]DOTA-NAP-amide. Over an observation period from 4 to 48 h, the tumor-to-kidney ratio of [ 111 In]DOTA-Phospho-MSH 2-9 was 35% more favorable than that of the reference compound. In a comparison of DOTA-NAP-d-Asp-d-Asp, DOTA-Phospho-MSH 2-9 and DOTA-NAP-amide with five previously published analogs of DOTA-NAP-amide that altogether cover a range of peptides with an overall net charge between +2 and -2, we now demonstrate that a net charge of -1, with the extra negative charges preferably placed in the N -terminal region, has led to the lowest kidney uptake and retention. Charges of +2 or -2 markedly increased kidney uptake and retention. In conclusion, the novel DOTA-Phospho-MSH 2-9 may represent a new lead compound for negatively charged linear MC1R ligands that can be further developed into a clinically relevant melanoma targeting radiopeptide.

  15. Receptor-Mediated Melanoma Targeting with Radiolabeled α-Melanocyte-Stimulating Hormone: Relevance of the Net Charge of the Ligand

    PubMed Central

    Bapst, Jean-Philippe; Eberle, Alex N.

    2017-01-01

    A majority of melanotic and amelanotic melanomas overexpress melanocortin type 1 receptors (MC1Rs) for α-melanocyte-stimulating hormone. Radiolabeled linear or cyclic analogs of α-MSH have a great potential as diagnostic or therapeutic tools for the management of malignant melanoma. Compounds such as [111In]DOTA-NAP-amide exhibit high affinity for the MC1R in vitro, good tumor uptake in vivo, but they may suffer from relatively high kidney uptake and retention in vivo. We have shown previously that the introduction of negative charges into radiolabeled DOTA-NAP-amide peptide analogs may enhance their excretion and reduce kidney retention. To address the question of where to place negative charges within the ligand, we have extended these studies by designing two novel peptides, Ac-Nle-Asp-His-d-Phe-Arg-Trp-Gly-Lys(DOTA)-d-Asp-d-Asp-OH (DOTA-NAP-d-Asp-d-Asp) with three negative charges at the C-terminal end (overall net charge of the molecule −2) and DOTA-Gly-Tyr(P)-Nle-Asp-His-d-Phe-Arg-Trp-NH2 (DOTA-Phospho-MSH2-9) with two negative charges in the N-terminal region (net charge −1). The former peptide showed markedly reduced receptor affinity and biological activity by >10-fold compared to DOTA-NAP-amide as reference compound, and the latter peptide displayed similar bioactivity and receptor affinity as the reference compound. The uptake by melanoma tumor tissue of [111In]DOTA-Phospho-MSH2-9 was 7.33 ± 0.47 %ID/g 4 h after injection, i.e., almost equally high as with [111In]DOTA-NAP-amide. The kidney retention was 2.68 ± 0.18 %ID/g 4 h after injection and hence 44% lower than that of [111In]DOTA-NAP-amide. Over an observation period from 4 to 48 h, the tumor-to-kidney ratio of [111In]DOTA-Phospho-MSH2-9 was 35% more favorable than that of the reference compound. In a comparison of DOTA-NAP-d-Asp-d-Asp, DOTA-Phospho-MSH2-9 and DOTA-NAP-amide with five previously published analogs of DOTA-NAP-amide that altogether cover a range of peptides with an overall net charge between +2 and −2, we now demonstrate that a net charge of −1, with the extra negative charges preferably placed in the N-terminal region, has led to the lowest kidney uptake and retention. Charges of +2 or −2 markedly increased kidney uptake and retention. In conclusion, the novel DOTA-Phospho-MSH2-9 may represent a new lead compound for negatively charged linear MC1R ligands that can be further developed into a clinically relevant melanoma targeting radiopeptide. PMID:28491052

  16. Double layers in contactor plasmas

    NASA Technical Reports Server (NTRS)

    Cooke, David L.

    1990-01-01

    The concept of using a hollow cathode to establish a low impedance contact between a spacecraft and the ambient plasma continues to gain in popularity, and is often then referred to as a plasma contactor. A growing number of studies indicate that large contact currents can be supported with small potential difference between the contactor and the ambient plasma. Results will be presented from a simple one-dimensional spherical model that obtains potentials from the solution of Poisson's equation, and particle densities from a turning point formalism that includes particle angular momentum. The neglect of collisions and magnetic field limits the realism. However, the results illustrate the effect of double layers that can form at the interface between contactor and ambient plasmas, when there is any voltage differential between the contactor and the ambient. The I-V characteristic of this model shows the usual space charge depends upon collection when the contactor flux is lower than some threshold; independence of I from variation in V when the flux is slightly greater than that threshold, and (numerical ?) instability for excessive flux suggesting the possibility of negative resistance. Even if a real I-V characteristic does not exhibit negative resistance, flat spots or high resistance regions may still be troublesome (or useful) to the total circuit.

  17. Identification of the lipopolysaccharide modifications controlled by the Salmonella PmrA/PmrB system mediating resistance to Fe(III) and Al(III)

    PubMed Central

    Nishino, Kunihiko; Hsu, Fong-Fu; Turk, John; Cromie, Michael J; Wösten, Marc M S M; Groisman, Eduardo A

    2006-01-01

    Iron is an essential metal but can be toxic in excess. While several homeostatic mechanisms prevent oxygen-dependent killing promoted by Fe(II), little is known about how cells cope with Fe(III), which kills by oxygen-independent means. Several Gram-negative bacterial species harbour a regulatory system – termed PmrA/PmrB – that is activated by and required for resistance to Fe(III). We now report the identification of the PmrA-regulated determinants mediating resistance to Fe(III) and Al(III) in Salmonella enterica serovar Typhimurium. We establish that these determinants remodel two regions of the lipopolysaccharide, decreasing the negative charge of this major constituent of the outer membrane. Remodelling entails the covalent modification of the two phosphates in the lipid A region with phosphoethanolamine and 4-aminoarabinose, which has been previously implicated in resistance to polymyxin B, as well as dephosphorylation of the Hep(II) phosphate in the core region by the PmrG protein. A mutant lacking the PmrA-regulated Fe(III) resistance genes bound more Fe(III) than the wild-type strain and was defective for survival in soil, suggesting that these PmrA-regulated lipopolysaccharide modifications aid Salmonella's survival and spread in non-host environments. PMID:16803591

  18. Negative bias-and-temperature stress-assisted activation of oxygen-vacancy hole traps in 4H-silicon carbide metal-oxide-semiconductor field-effect transistors

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Ettisserry, D. P., E-mail: deva@umd.edu, E-mail: neil@umd.edu; Goldsman, N., E-mail: deva@umd.edu, E-mail: neil@umd.edu; Akturk, A.

    We use hybrid-functional density functional theory-based Charge Transition Levels (CTLs) to study the electrical activity of near-interfacial oxygen vacancies located in the oxide side of 4H-Silicon Carbide (4H-SiC) power Metal-Oxide-Semiconductor Field-Effect Transistors (MOSFETs). Based on the “amorphousness” of their local atomic environment, oxygen vacancies are shown to introduce their CTLs either within (permanently electrically active) or outside of (electrically inactive) the 4H-SiC bandgap. The “permanently electrically active” centers are likely to cause threshold voltage (V{sub th}) instability at room temperature. On the other hand, we show that the “electrically inactive” defects could be transformed into various “electrically active” configurations undermore » simultaneous application of negative bias and high temperature stresses. Based on this observation, we present a model for plausible oxygen vacancy defects that could be responsible for the recently observed excessive worsening of V{sub th} instability in 4H-SiC power MOSFETs under high temperature-and-gate bias stress. This model could also explain the recent electrically detected magnetic resonance observations in 4H-SiC MOSFETs.« less

  19. Probing Charge Carrier Dynamics in Porphyrin-Based Organic Semiconductor Thin Films by Time-Resolved THz Spectroscopy.

    PubMed

    Ohta, Kaoru; Tokonami, Shunrou; Takahashi, Kotaro; Tamura, Yuto; Yamada, Hiroko; Tominaga, Keisuke

    2017-11-02

    To improve the power conversion efficiency of solar cells, it is important to understand the underlying relaxation mechanisms of photogenerated charge carriers in organic semiconductors. In this work, we studied the charge carrier dynamics of diketopyrrolopyrrole-linked tetrabenzoporphyrin thin films where the diketopyrrolopyrrole unit has two n-butyl groups, abbreviated as C4-DPP-BP. We used time-resolved terahertz (THz) spectroscopy to track charge carrier dynamics with excitations at 800 and 400 nm. Compared with tetrabenzoporphyrin (BP), the extension of π-electron delocalization to the diketopyrrolopyrrole peripherals leads to an increase in absorption in the near-infrared region. Following the excitation at 800 nm, we found that the transient THz signals in C4-DPP-BP thin films decay with time constants of 0.5 and 9.1 ps, with small residual components. With excitation at 400 nm, we found that the transient THz signals decay with time constants of 0.4 and 7.5 ps. On the basis of the similarity of the decay profiles of the transient THz signals obtained with excitations at 400 and 800 nm, we considered that the decaying components are due to charge carrier recombination and/or trapping at defect sites, which do not depend on the excess energy of the photoexcitation. In contrast to BP, even without an electron acceptor, we observed the finite offset of the transient THz signals at 100 ps, demonstrating the existence of long-lived charge carriers. We also measured the photoconductivity spectra of C4-DPP-BP thin films with the excitation at both 800 and 400 nm. It was found that the spectra can be fitted by the Drude-Smith model. From these results, it was determined that the charge carriers are localized right after photoexcitation. At 0.4 ps, the product of the quantum yield of charge generation and mobility of charge carriers at 400 nm is approximately twice that obtained at 800 nm. We discuss the implications of the excess excitation energy in organic semiconductor-based devices.

  20. Profiling of Current Transients in Capacitor Type Diamond Sensors.

    PubMed

    Gaubas, Eugenijus; Ceponis, Tomas; Meskauskaite, Dovile; Kazuchits, Nikolai

    2015-06-08

    The operational characteristics of capacitor-type detectors based on HPHT and CVD diamond have been investigated using perpendicular and parallel injection of carrier domain regimes. Simulations of the drift-diffusion current transients have been implemented by using dynamic models based on Shockley-Ramo's theorem, under injection of localized surface domains and of bulk charge carriers. The bipolar drift-diffusion regimes have been analyzed for the photo-induced bulk domain (packet) of excess carriers. The surface charge formation and polarization effects dependent on detector biasing voltage have been revealed. The screening effects ascribed to surface charge and to dynamics of extraction of the injected bulk excess carrier domain have been separated and explained. The parameters of drift mobility of the electrons μ(e) = 4000 cm2/Vs and holes μ(h) = 3800 cm2/Vs have been evaluated for CVD diamond using the perpendicular profiling of currents. The coefficient of carrier ambipolar diffusion D(a) = 97 cm2/s and the carrier recombination lifetime τ(R,CVD) ≌ 110 ns in CVD diamond were extracted by combining analysis of the transients of the sensor current and the microwave probed photoconductivity. The carrier trapping with inherent lifetime τR,HPHT ≌ 2 ns prevails in HPHT diamond.

  1. Monte Carlo simulation and equation of state for flexible charged hard-sphere chain fluids: Polyampholyte and polyelectrolyte solutions

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Jiang, Hao; Adidharma, Hertanto, E-mail: adidharm@uwyo.edu

    The thermodynamic modeling of flexible charged hard-sphere chains representing polyampholyte or polyelectrolyte molecules in solution is considered. The excess Helmholtz energy and osmotic coefficients of solutions containing short polyampholyte and the osmotic coefficients of solutions containing short polyelectrolytes are determined by performing canonical and isobaric-isothermal Monte Carlo simulations. A new equation of state based on the thermodynamic perturbation theory is also proposed for flexible charged hard-sphere chains. For the modeling of such chains, the use of solely the structure information of monomer fluid for calculating the chain contribution is found to be insufficient and more detailed structure information must thereforemore » be considered. Two approaches, i.e., the dimer and dimer-monomer approaches, are explored to obtain the contribution of the chain formation to the Helmholtz energy. By comparing with the simulation results, the equation of state with either the dimer or dimer-monomer approach accurately predicts the excess Helmholtz energy and osmotic coefficients of polyampholyte and polyelectrolyte solutions except at very low density. It also well captures the effect of temperature on the thermodynamic properties of these solutions.« less

  2. Controlling the Local Electronic Properties of Si(553)-Au through Hydrogen Doping

    NASA Astrophysics Data System (ADS)

    Hogan, C.; Speiser, E.; Chandola, S.; Suchkova, S.; Aulbach, J.; Schäfer, J.; Meyer, S.; Claessen, R.; Esser, N.

    2018-04-01

    We propose a quantitative and reversible method for tuning the charge localization of Au-stabilized stepped Si surfaces by site-specific hydrogenation. This is demonstrated for Si(553)-Au as a model system by combining density functional theory simulations and reflectance anisotropy spectroscopy experiments. We find that controlled H passivation is a two-step process: step-edge adsorption drives excess charge into the conducting metal chain "reservoir" and renders it insulating, while surplus H recovers metallic behavior. Our approach illustrates a route towards microscopic manipulation of the local surface charge distribution and establishes a reversible switch of site-specific chemical reactivity and magnetic properties on vicinal surfaces.

  3. Search for a heavy gauge boson decaying to a charged lepton and a neutrino in 1 fb -1 of pp collisions at √s = 7 TeV using the ATLAS detector

    DOE PAGES

    Aad, G.

    2011-11-01

    The ATLAS detector at the LHC is used to search for heavy charged gauge bosons (W'), decaying to a charged lepton (electron or muon) and a neutrino. Results are presented based on the analysis of pp collisions at a center-of-mass energy of 7 TeV corresponding to an integrated luminosity of 1.04 fb⁻¹. No excess beyond Standard Model expectations is observed. A W' with Sequential Standard Model couplings is excluded at the 95% confidence level for masses up to 2.15 TeV.

  4. Persistent photoconductivity due to trapping of induced charges in Sn/ZnO thin film based UV photodetector

    NASA Astrophysics Data System (ADS)

    Yadav, Harish Kumar; Sreenivas, K.; Gupta, Vinay

    2010-05-01

    Photoconductivity relaxation in rf magnetron sputtered ZnO thin films integrated with ultrathin tin metal overlayer is investigated. Charge carriers induced at the ZnO-metal interface by the tin metal overlayer compensates the surface lying trap centers and leads to the enhanced photoresponse. On termination of ultraviolet radiation, recombination of the photoexcited electrons with the valence band holes leaves the excess carriers deeply trapped at the recombination center and holds the dark conductivity level at a higher value. Equilibrium between the recombination centers and valence band, due to trapped charges, eventually stimulates the persistent photoconductivity in the Sn/ZnO photodetectors.

  5. Structure, stability, and thermodynamics of lamellar DNA-lipid complexes.

    PubMed Central

    Harries, D; May, S; Gelbart, W M; Ben-Shaul, A

    1998-01-01

    We develop a statistical thermodynamic model for the phase evolution of DNA-cationic lipid complexes in aqueous solution, as a function of the ratios of charged to neutral lipid and charged lipid to DNA. The complexes consist of parallel strands of DNA intercalated in the water layers of lamellar stacks of mixed lipid bilayers, as determined by recent synchrotron x-ray measurements. Elastic deformations of the DNA and the lipid bilayers are neglected, but DNA-induced spatial inhomogeneities in the bilayer charge densities are included. The relevant nonlinear Poisson-Boltzmann equation is solved numerically, including self-consistent treatment of the boundary conditions at the polarized membrane surfaces. For a wide range of lipid compositions, the phase evolution is characterized by three regions of lipid to DNA charge ratio, rho: 1) for low rho, the complexes coexist with excess DNA, and the DNA-DNA spacing in the complex, d, is constant; 2) for intermediate rho, including the isoelectric point rho = 1, all of the lipid and DNA in solution is incorporated into the complex, whose inter-DNA distance d increases linearly with rho; and 3) for high rho, the complexes coexist with excess liposomes (whose lipid composition is different from that in the complex), and their spacing d is nearly, but not completely, independent of rho. These results can be understood in terms of a simple charging model that reflects the competition between counterion entropy and inter-DNA (rho < 1) and interbilayer (rho > 1) repulsions. Finally, our approach and conclusions are compared with theoretical work by others, and with relevant experiments. PMID:9649376

  6. Mitigation in Multiple Effects of Graphene Oxide Toxicity in Zebrafish Embryogenesis Driven by Humic Acid.

    PubMed

    Chen, Yuming; Ren, Chaoxiu; Ouyang, Shaohu; Hu, Xiangang; Zhou, Qixing

    2015-08-18

    Graphene oxide (GO) is a widely used carbonaceous nanomaterial. To date, the influence of natural organic matter (NOM) on GO toxicity in aquatic vertebrates has not been reported. During zebrafish embryogenesis, GO induced a significant hatching delay and cardiac edema. The intensive interactions of GO with the chorion induces damage to chorion protuberances, excessive generation of (•)OH, and changes in protein secondary structure. In contrast, humic acid (HA), a ubiquitous form of NOM, significantly relieved the above adverse effects. HA reduced the interactions between GO and the chorion and mitigated chorion damage by regulating the morphology, structures, and surface negative charges of GO. HA also altered the uptake and deposition of GO and decreased the aggregation of GO in embryonic yolk cells and deep layer cells. Furthermore, HA mitigated the mitochondrial damage and oxidative stress induced by GO. This work reveals a feasible antidotal mechanism for GO in the presence of NOM and avoids overestimating the risks of GO in the natural environment.

  7. Citrate metabolism in blood transfusions and its relationship due to metabolic alkalosis and respiratory acidosis

    PubMed Central

    Li, Kai; Xu, Yuan

    2015-01-01

    Metabolic alkalosis commonly results from excessive hydrochloric acid (HCl), potassium (K+) and water (H2O) loss from the stomach or through the urine. The plasma anion gap increases in non-hypoproteinemic metabolic alkalosis due to an increased negative charge equivalent on albumin and the free ionized calcium (Ca++) content of plasma decreases. The mean citrate load in all patients was 8740±7027 mg from 6937±6603 mL of transfused blood products. The citrate load was significantly higher in patients with alkalosis (9164±4870 vs. 7809±3967, P < 0.05). The estimated mean total citrate administered via blood and blood products was calculated as 43.2±34.19 mg/kilogram/day. In non-massive and frequent blood transfusions, the elevated carbon dioxide output has been shown to occur. Due to citrate metabolism causes intracellular acidosis. As a result of intracellular acidosis compensation, decompensated metabolic alkalosis + respiratory acidosis and electrolyte imbalance may develop, blood transfusions may result in certain complications. PMID:26131288

  8. Citrate metabolism in blood transfusions and its relationship due to metabolic alkalosis and respiratory acidosis.

    PubMed

    Li, Kai; Xu, Yuan

    2015-01-01

    Metabolic alkalosis commonly results from excessive hydrochloric acid (HCl), potassium (K(+)) and water (H2O) loss from the stomach or through the urine. The plasma anion gap increases in non-hypoproteinemic metabolic alkalosis due to an increased negative charge equivalent on albumin and the free ionized calcium (Ca(++)) content of plasma decreases. The mean citrate load in all patients was 8740±7027 mg from 6937±6603 mL of transfused blood products. The citrate load was significantly higher in patients with alkalosis (9164±4870 vs. 7809±3967, P < 0.05). The estimated mean total citrate administered via blood and blood products was calculated as 43.2±34.19 mg/kilogram/day. In non-massive and frequent blood transfusions, the elevated carbon dioxide output has been shown to occur. Due to citrate metabolism causes intracellular acidosis. As a result of intracellular acidosis compensation, decompensated metabolic alkalosis + respiratory acidosis and electrolyte imbalance may develop, blood transfusions may result in certain complications.

  9. Electron kinetics at the plasma interface

    NASA Astrophysics Data System (ADS)

    Bronold, Franz Xaver; Fehske, Holger; Pamperin, Mathias; Thiessen, Elena

    2018-05-01

    The most fundamental response of an ionized gas to a macroscopic object is the formation of the plasma sheath. It is an electron depleted space charge region, adjacent to the object, which screens the object's negative charge arising from the accumulation of electrons from the plasma. The plasma sheath is thus the positively charged part of an electric double layer whose negatively charged part is inside the wall. In the course of the Transregional Collaborative Research Center SFB/TRR24 we investigated, from a microscopic point of view, the elementary charge transfer processes responsible for the electric double layer at a floating plasma-wall interface and made first steps towards a description of the negative part of the layer inside the wall. Below we review our work in a colloquial manner, describe possible extensions, and identify key issues which need to be resolved to make further progress in the understanding of the electron kinetics across plasma-wall interfaces. Contribution to the Topical Issue "Fundamentals of Complex Plasmas", edited by Jürgen Meichsner, Michael Bonitz, Holger Fehske, Alexander Piel.

  10. 49 CFR 1141.1 - Procedures to calculate interest rates.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... compounding period shall run from the date the unlawful charge is paid to the last day of the current calendar... in an effective rate in excess of the nominal rate. Under this “exponential” approach, the total...

  11. 41 CFR 302-10.207 - Am I responsible for excess or non-allowable charges?

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... designated in the tariffs as “Special Service;” (c) Cost of storage; and (d) Costs of connecting/disconnecting appliances, equipment, and utilities involved in relocation and costs of converting appliances for...

  12. Characteristics of space charge formed in a laminated LDPE/EVA dielectric under DC stress

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Tanaka, Toshikatsu; Kisanuki, Osamu; Sakata, Masataka

    1996-12-31

    A laser-induced pressure pulse (LIPP) method was used for measuring the space charge distribution of LDPE/EVA laminate dielectrics under dc stress. The constant voltage up to {+-}20 kV was applied to a side of the laminates of 0.5 mm thickness for 30 minutes. The other side is grounded. When the amount of space charge was measured by LIPP, both sides were virtually grounded. Space charge built up in or near the interface between LDPE and EVA was mainly investigated. Positive and negative voltage was applied to the side of LDPE in the laminates. It was clarified that the space chargemore » was larger in case of LDPE negatively biased than in case of LDPE positively biased. The density of the space charge ranged around 1 nC/mm{sup 3}. The formation of interfacial space charge is analyzed.« less

  13. Performances of nanofiltration and low pressure reverse osmosis membranes for desalination: characterization and modelling

    NASA Astrophysics Data System (ADS)

    Boussouga, Y. A.; Lhassani, A.

    2017-03-01

    The nanofiltration and the reverse osmosis processes are the most common techniques for the desalination of water contaminated by an excess of salts. In this present study, we were interested in the characterization of commercial, composite and asymmetric membranes of nanofiltration (NF90, NF270) and low pressure reverse osmosis (BW30LE). The two types of characterization that we opted for our study: (i) characterization of electrical proprieties, in terms of the surface charge of various membranes studied by the measurement of the streaming potential, (ii) hydrodynamic characterization in terms of hydraulic permeability with pure water, mass transfer and phenomenological parameters for each system membrane/salt using hydrodynamic approaches. The irreversible thermodynamics allowed us to model the observed retention Robs of salts (NaCl and Na2SO4) for the different membranes studied, to understand and to predict a good filtration with a membrane. A study was conducted on the type of mass transfer for each system membrane/salt: convection and diffusion. The results showed that all tested membranes are negatively charged for the solutions at neutral pH, this is explained by their material composition. The results also showed competitiveness between the different types of membranes. In view of that the NF remains effective in terms of selective retention with less energy consumption than LPRO.

  14. Interactions of PAMAM dendrimers with SDS at the solid-liquid interface.

    PubMed

    Arteta, Marianna Yanez; Eltes, Felix; Campbell, Richard A; Nylander, Tommy

    2013-05-14

    This work addresses structural and nonequilibrium effects of the interactions between well-defined cationic poly(amidoamine) PAMAM dendrimers of generations 4 and 8 and the anionic surfactant sodium dodecyl sulfate (SDS) at the hydrophilic silica-water interface. Neutron reflectometry and quartz crystal microbalance with dissipation monitoring were used to reveal the adsorption from premixed dendrimer/surfactant solutions as well as sequential addition of the surfactant to preadsorbed layers of dendrimers. PAMAM dendrimers of both generations adsorb to hydrophilic silica as a compact monolayer, and the adsorption is irreversible upon rinsing with salt solution. SDS adsorbs on the dendrimer layer and at low bulk concentrations causes the expansion of the dendrimer layers on the surface. When the bulk concentration of SDS is increased, the surfactant layer consists of aggregates or bilayer-like structures. The adsorption of surfactant is reversible upon rinsing, but slight changes of the structure of the preadsorbed PAMAM monolayer were observed. The adsorption from premixed solutions close to charge neutrality results in thick multilayers, but the surface excess is lower when the bulk complexes have a net negative charge. A critical examination of the pathway of adsorption for the interactions of SDS with preadsorbed PAMAM monolayers and premixed PAMAM/SDS solutions with hydrophilic silica revealed that nonequilibrium effects are important only in the latter case, and the application of a thermodynamic model to such experimental data would be inappropriate.

  15. Transmission of low-energy negative ions through insulating nanocapillaries

    NASA Astrophysics Data System (ADS)

    Zhang, Qi; Liu, Zhonglin; Li, Pengfei; Jin, Bo; Song, Guangyin; Jin, Dingkun; Niu, Ben; Wei, Long; Ha, Shuai; Xie, Yiming; Ma, Yue; Wan, Chengliang; Cui, Ying; Zhou, Peng; Zhang, Hongqiang; Chen, Ximeng

    2018-04-01

    A simulation is performed to study the transmission of low-energy C l- ions through A l2O3 nanocapillaries. For the trajectory simulations, there are several processes involved: the image forces induced by the projectile; the electrostatic force from the deposited charges; the scattering from the inner surface and charge exchange. The simulation reproduces the main features of the experiments; i.e., the double peak structure in the transmitted angular distribution and the transmitted fractions of C l- , C l+ , and C l0 were found in the charge state distribution. The transmitted C l- ions are centered around the beam direction while the transmitted fractions of C l0 and C l+ are centered around the tilt angles. The role of the deposited charge is also studied by simulations. With the deposited charge, it is found that C l- is dominant in the transmission and the majority of the ions, centered around the tilt angle, are mainly from the single deflection by the negative charge patches on the inner surfaces of the capillaries, and only a few directly transmitted C l- ions are centered around the incident direction. There are also a few transmitted fractions of C l0 and C l+ from close surface scatterings. In the case that there are no negative charge patches, the simulation agrees with the experiment in detail: The majority of the directly transmitted C l- ions are centered around the incident direction while only a few scattered C l- ions are centered around the tilt angle from the single close collisions with the inner surfaces of the capillaries. There is a portion, comparable to the transmitted fraction of C l- , of the transmitted fractions of C l0 and C l+ , centered around the tilt angle, from the single scatterings with the inner surfaces of the capillaries. This confirms that at the present experimental conditions there are most probably no negative charge patches formed to guide the negative ions through insulating A l2O3 nanocapillaries.

  16. Lysozyme adsorption in pH-responsive hydrogel thin-films: the non-trivial role of acid-base equilibrium.

    PubMed

    Narambuena, Claudio F; Longo, Gabriel S; Szleifer, Igal

    2015-09-07

    We develop and apply a molecular theory to study the adsorption of lysozyme on weak polyacid hydrogel films. The theory explicitly accounts for the conformation of the network, the structure of the proteins, the size and shape of all the molecular species, their interactions as well as the chemical equilibrium of each titratable unit of both the protein and the polymer network. The driving forces for adsorption are the electrostatic attractions between the negatively charged network and the positively charged protein. The adsorption is a non-monotonic function of the solution pH, with a maximum in the region between pH 8 and 9 depending on the salt concentration of the solution. The non-monotonic adsorption is the result of increasing negative charge of the network with pH, while the positive charge of the protein decreases. At low pH the network is roughly electroneutral, while at sufficiently high pH the protein is negatively charged. Upon adsorption, the acid-base equilibrium of the different amino acids of the protein shifts in a nontrivial fashion that depends critically on the particular kind of residue and solution composition. Thus, the proteins regulate their charge and enhance adsorption under a wide range of conditions. In particular, adsorption is predicted above the protein isoelectric point where both the solution lysozyme and the polymer network are negatively charged. This behavior occurs because the pH in the interior of the gel is significantly lower than that in the bulk solution and it is also regulated by the adsorption of the protein in order to optimize protein-gel interactions. Under high pH conditions we predict that the protein changes its charge from negative in the solution to positive within the gel. The change occurs within a few nanometers at the interface of the hydrogel film. Our predictions show the non-trivial interplay between acid-base equilibrium, physical interactions and molecular organization under nanoconfined conditions, which leads to non-trivial adsorption behavior that is qualitatively different from what would be predicted from the state of the proteins in the bulk solution.

  17. A new biphasic osteoinductive calcium composite material with a negative Zeta potential for bone augmentation

    PubMed Central

    Smeets, Ralf; Kolk, Andreas; Gerressen, Marcus; Driemel, Oliver; Maciejewski, Oliver; Hermanns-Sachweh, Benita; Riediger, Dieter; Stein, Jamal M

    2009-01-01

    The aim of the present study was to analyze the osteogenic potential of a biphasic calcium composite material (BCC) with a negative surface charge for maxillary sinus floor augmentation. In a 61 year old patient, the BCC material was used in a bilateral sinus floor augmentation procedure. Six months postoperative, a bone sample was taken from the augmented regions before two titanium implants were inserted at each side. We analyzed bone neoformation by histology, bone density by computed tomography, and measured the activity of voltage-activated calcium currents of osteoblasts and surface charge effects. Control orthopantomograms were carried out five months after implant insertion. The BCC was biocompatible and replaced by new mineralized bone after being resorbed completely. The material demonstrated a negative surface charge (negative Zeta potential) which was found to be favorable for bone regeneration and osseointegration of dental implants. PMID:19523239

  18. Fetal programming: excess prenatal testosterone reduces postnatal luteinizing hormone, but not follicle-stimulating hormone responsiveness, to estradiol negative feedback in the female.

    PubMed

    Sarma, Hirendra N; Manikkam, Mohan; Herkimer, Carol; Dell'Orco, James; Welch, Kathleen B; Foster, Douglas L; Padmanabhan, Vasantha

    2005-10-01

    Exposure of female sheep fetuses to excess testosterone (T) during early to midgestation produces postnatal hypergonadotropism manifest as a selective increase in LH. This hypergonadotropism may result from reduced sensitivity to estradiol (E2) negative feedback and/or increased pituitary sensitivity to GnRH. We tested the hypothesis that excess T before birth reduces responsiveness of LH and FSH to E2 negative feedback after birth. Pregnant ewes were treated with T propionate (100 mg/kg in cotton seed oil) or vehicle twice weekly from d 30-90 gestation. Responsiveness to E2 negative feedback was assessed at 12 and 24 wk of age in the ovary-intact female offspring. Our experimental strategy was first to arrest follicular growth and reduce endogenous E2 by administering the GnRH antagonist (GnRH-A), Nal-Glu (50 microg/kg sc every 12 h for 72 h), and then provide a fixed amount of exogenous E2 via an implant. Blood samples were obtained every 20 min at 12 wk and every 10 min at 24 wk before treatment, during and after GnRH-A treatment both before and after E2 implant. GnRH-A ablated LH pulsatility, reduced FSH by approximately 25%, and E2 production diminished to near detection limit of assay at both ages in both groups. Prenatal T treatment produced a precocious and selective reduction in responsiveness of LH but not FSH to E2 negative feedback, which was manifest mainly at the level of LH/GnRH pulse frequency. Collectively, these findings support the hypothesis that prenatal exposure to excess T decreases postnatal responsiveness to E2 inhibitory feedback of LH/GnRH secretion to contribute to the development of hypergonadotropism.

  19. Modeling carbonaceous particle formation in an argon graphite cathode dc discharge

    NASA Astrophysics Data System (ADS)

    Michau, A.; Lombardi, G.; Colina Delacqua, L.; Redolfi, M.; Arnas, C.; Bonnin, X.; Hassouni, K.

    2010-12-01

    We develop a model for the nucleation, growth and transport of carbonaceous dust particles in a non-reactive gas dc discharge where the carbon source is provided by cathode sputtering. We consider only the initial phase of the discharge when the dust charge density remains small with respect to the electron density. We find that an electric field reversal at the entrance of the negative glow region promotes trapping of negatively charged clusters and dust particles, confining them for long times in the plasma and favoring molecular growth. An essential ingredient for this process is electron attachment, which negatively charges the initially neutral clusters. We perform sensitivity studies on several number parameters: size of the largest molecular edifice, sticking coefficient, etc.

  20. Nanoparticle coagulation in fractionally charged and charge fluctuating dusty plasmas

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Nunomura, Shota; Kondo, Michio; Shiratani, Masaharu

    2008-08-15

    The kinetics of nanoparticle coagulation has been studied in fractionally charged and charge fluctuating dusty plasmas. The coagulation occurs when the mutual collision frequency among nanoparticles exceeds their charging and decharging/neutralization frequency. Interestingly, the coagulation is suppressed while a fraction (several percent) of nanoparticles are negatively charged in a plasma, in which stochastic charging plays an important role. A model is developed to predict a phase diagram of the coagulation and its suppression.

  1. The patterns and implications of diurnal variations in d-excess of plant water, shallow soil water and air moisture

    NASA Astrophysics Data System (ADS)

    Zhao, L.; Wang, L.; Xiao, H.; Cheng, G.; Ruan, Y.; Zhou, M.; Wang, F.

    2014-04-01

    Deuterium excess (d-excess) of air moisture is traditionally considered as a conservative tracer of oceanic evaporation conditions. Recent studies challenge this view and emphasize the importance of vegetation activity in controlling the dynamics of air moisture d-excess. However direct field observations supporting the role of vegetation in d-excess variations is not well documented. In this study, we quantified d-excess of air moisture, leaf and xylem water of multiple dominant species as well as shallow soil water (5 and 10 cm) at hourly interval during three extensive field campaigns at two climatically different locations within the Heihe River Basin. The results showed that with the increase of temperature (T) and decrease of relative humidity (RH), the δD-δ18O plots of leaf water, xylem water and shallow soil water deviated gradually from their corresponding local meteoric water line. There were significant differences in d-excess values among different water pools at all the study sites. The most positive d-excess values were found in air moisture (9.3‰) and the most negative d-excess values (-85.6‰) were found in leaf water. The d-excess values of air moisture (dmoisture) and leaf water (dleaf) during the sunny days, and shallow soil water (dsoil) during the first sunny day after rain event showed strong diurnal patterns. There were significantly positive relationships between dleaf and RH and negative relationships between dmoisture and RH. The correlations of dleaf and dmoisture with T were opposite to their relationships with RH. In addition, we found the opposite diurnal variations for dleaf and dmoisture during the sunny day, and for dleaf during the sunny days, and shallow soil water dsoil and dmoisture during the first sunny day after rain event. Significant negative relationships were found between dleaf and dmoisture in all the sites during the sunny day. Our results provide direct evidence that dmoisture of the surface air at continental locations can be significantly altered by local processes, especially plant transpiration during the sunny days. The role of shallow soil water on dmoisture is generally much smaller but could be large at the sunny day right after rainfall events.

  2. A Brief 30-Year Review: Research Highlights from Lightning Mapping Systems 1970-2000

    NASA Astrophysics Data System (ADS)

    MacGorman, D. R.

    2016-12-01

    Modern lightning mapping began in the 1970s, the decade in which VHF mapping systems, acoustic mapping systems, and ground strike locating systems were introduced. Adding GPS synchronization of VHF systems in the late 1990s enabled real-time VHF mapping systems to be deployed more extensively. Data these systems provided by 2000 revolutionized our understanding of how storms produce lightning. Among key results: Electrostatics, not electrodynamics, governs where lightning is initiated and where it propagates, contrary to early expectations. Lightning is initiated in a region of large electric field magnitude, typically between a positive charge region and a negative charge region. The geometry of a storm's charge regions governs the spatial extent of each end of the flash. The flash initially propagates bidirectionally toward the two charge regions that initiated it, and once it reaches the charge regions and maximizes the ambient potential difference spanned by the flash structure, it extends through each charge region's ambient electric potential well until the total electric field magnitude at the ends of the flash drops below the threshold for continued propagation. The typical charge distribution producing a cloud-to-ground flash is a region of charge of the polarity being lowered to ground, above a lesser amount of charge of the opposite polarity; the lower region has too little charge to capture the downward propagating channel. Contrary to previous understanding, naturally occurring cloud-to-ground lightning often lowers positive charge to ground, instead of the usual negative charge, in several situations, including winter storms, stratiform precipitation regions, some severe storms, and storms on the High Plains of the United States. The reason cloud-to-ground activity in some storms is dominated by flashes that lower positive charge to ground is that the polarity of the main charge regions in those storms is inverted from the usual polarity, with the main mid-level charge being positive and the main upper-level charge being negative. This strongly implies that the dominant non-inductive electrification mechanism is inverted in those storms, probably because the liquid water content in the mixed phase region is larger than in most storms.

  3. Investigation of Dusts Effect and Negative Ion in DC Plasmas by Electric Probes

    NASA Astrophysics Data System (ADS)

    Oh, Hye Taek; Kang, Inje; Bae, Min-Keun; Park, Insun; Lee, Seunghwa; Jeong, Seojin; Chung, Kyu-Sun

    2017-10-01

    Dust is typically negatively charged by electron attachment whose thermal velocities are fast compared to that of the heavier ions. The negatively charged particles can play a role of negative ions which affect the quasi-neutrality of background plasma. To investigate effect of metal dusts and negative ion on plasma and materials, metal dusts are injected into background Ar plasma which is generated by tungsten filament using dust dispenser on Cubical Plasma Device (CPD). The CPD has following conditions: size =24x24x24cm3, plasma source =DC filament plasma (ne 1x10x1010, Te 2eV), background gas =Ar, dusts =tungsten powder (diameter 1.89micron). The dust dispenser is developed to quantitate of metal dust by ultrasonic transducer. Electronegative plasmas are generated by adding O2 + Ar plasma to compare negative ion and dust effect. A few grams of micron-sized dusts are placed in the dust dispenser which is located at the upper side of the Cubical Plasma Device. The falling particles by dust dispenser are mainly charged up by the collection of the background plasma. The change in parameters due to negative ion production are characterized by measuring the floating and plasma potential, electron temperature and negative ion density using electric probes.

  4. The Acquisition of Development of Advanced Processing Techniques for CCD Arrays.

    DTIC Science & Technology

    1981-01-01

    E57B 96 x 2048 TDI imager production run. A minor change was incorporated on wafers #1-3; an in situ doped-polysilicon technique was used instead of the...2047, - 10 - Ab-A~ and 2048 . In some cases charge collection extends beyond these pixels. The excess signal is measured here as a percentage (Table...amount of spurious charge in pixels #2047 and 2048 is always greater than for pixels #2 and 1, respectively. This is because there is more unshielded area

  5. Observation of Transverse Spin-Dependent Azimuthal Correlations of Charged Pion Pairs in p↑+p at √{s }=200 GeV

    NASA Astrophysics Data System (ADS)

    Adamczyk, L.; Adkins, J. K.; Agakishiev, G.; Aggarwal, M. M.; Ahammed, Z.; Alekseev, I.; Alford, J.; Aparin, A.; Arkhipkin, D.; Aschenauer, E. C.; Averichev, G. S.; Banerjee, A.; Bellwied, R.; Bhasin, A.; Bhati, A. K.; Bhattarai, P.; Bielcik, J.; Bielcikova, J.; Bland, L. C.; Bordyuzhin, I. G.; Bouchet, J.; Brandin, A. V.; Bunzarov, I.; Burton, T. P.; Butterworth, J.; Caines, H.; Calderón de la Barca Sánchez, M.; Campbell, J. M.; Cebra, D.; Cervantes, M. C.; Chakaberia, I.; Chaloupka, P.; Chang, Z.; Chattopadhyay, S.; Chen, J. H.; Chen, X.; Cheng, J.; Cherney, M.; Christie, W.; Contin, G.; Crawford, H. J.; Das, S.; De Silva, L. C.; Debbe, R. R.; Dedovich, T. G.; Deng, J.; Derevschikov, A. A.; di Ruzza, B.; Didenko, L.; Dilks, C.; Dong, X.; Drachenberg, J. L.; Draper, J. E.; Du, C. M.; Dunkelberger, L. E.; Dunlop, J. C.; Efimov, L. G.; Engelage, J.; Eppley, G.; Esha, R.; Evdokimov, O.; Eyser, O.; Fatemi, R.; Fazio, S.; Federic, P.; Fedorisin, J.; Feng, Z.; Filip, P.; Fisyak, Y.; Flores, C. E.; Fulek, L.; Gagliardi, C. A.; Garand, D.; Geurts, F.; Gibson, A.; Girard, M.; Greiner, L.; Grosnick, D.; Gunarathne, D. S.; Guo, Y.; Gupta, S.; Gupta, A.; Guryn, W.; Hamad, A.; Hamed, A.; Haque, R.; Harris, J. W.; He, L.; Heppelmann, S.; Heppelmann, S.; Hirsch, A.; Hoffmann, G. W.; Hofman, D. J.; Horvat, S.; Huang, B.; Huang, X.; Huang, H. Z.; Huck, P.; Humanic, T. J.; Igo, G.; Jacobs, W. W.; Jang, H.; Jiang, K.; Judd, E. G.; Kabana, S.; Kalinkin, D.; Kang, K.; Kauder, K.; Ke, H. W.; Keane, D.; Kechechyan, A.; Khan, Z. H.; Kikola, D. P.; Kisel, I.; Kisiel, A.; Kochenda, L.; Koetke, D. D.; Kollegger, T.; Kosarzewski, L. K.; Kraishan, A. F.; Kravtsov, P.; Krueger, K.; Kulakov, I.; Kumar, L.; Kycia, R. A.; Lamont, M. A. C.; Landgraf, J. M.; Landry, K. D.; Lauret, J.; Lebedev, A.; Lednicky, R.; Lee, J. H.; Li, X.; Li, C.; Li, W.; Li, Z. M.; Li, Y.; Li, X.; Lisa, M. A.; Liu, F.; Ljubicic, T.; Llope, W. J.; Lomnitz, M.; Longacre, R. S.; Luo, X.; Ma, Y. G.; Ma, G. L.; Ma, L.; Ma, R.; Magdy, N.; Majka, R.; Manion, A.; Margetis, S.; Markert, C.; Masui, H.; Matis, H. S.; McDonald, D.; Meehan, K.; Minaev, N. G.; Mioduszewski, S.; Mohanty, B.; Mondal, M. M.; Morozov, D.; Mustafa, M. K.; Nandi, B. K.; Nasim, Md.; Nayak, T. K.; Nigmatkulov, G.; Nogach, L. V.; Noh, S. Y.; Novak, J.; Nurushev, S. B.; Odyniec, G.; Ogawa, A.; Oh, K.; Okorokov, V.; Olvitt, D.; Page, B. S.; Pak, R.; Pan, Y. X.; Pandit, Y.; Panebratsev, Y.; Pawlik, B.; Pei, H.; Perkins, C.; Peterson, A.; Pile, P.; Planinic, M.; Pluta, J.; Poljak, N.; Poniatowska, K.; Porter, J.; Posik, M.; Poskanzer, A. M.; Pruthi, N. K.; Putschke, J.; Qiu, H.; Quintero, A.; Ramachandran, S.; Raniwala, R.; Raniwala, S.; Ray, R. L.; Ritter, H. G.; Roberts, J. B.; Rogachevskiy, O. V.; Romero, J. L.; Roy, A.; Ruan, L.; Rusnak, J.; Rusnakova, O.; Sahoo, N. R.; Sahu, P. K.; Sakrejda, I.; Salur, S.; Sandweiss, J.; Sarkar, A.; Schambach, J.; Scharenberg, R. P.; Schmah, A. M.; Schmidke, W. B.; Schmitz, N.; Seger, J.; Seyboth, P.; Shah, N.; Shahaliev, E.; Shanmuganathan, P. V.; Shao, M.; Sharma, M. K.; Sharma, B.; Shen, W. Q.; Shi, S. S.; Shou, Q. Y.; Sichtermann, E. P.; Sikora, R.; Simko, M.; Skoby, M. J.; Smirnov, D.; Smirnov, N.; Song, L.; Sorensen, P.; Spinka, H. M.; Srivastava, B.; Stanislaus, T. D. S.; Stepanov, M.; Stock, R.; Strikhanov, M.; Stringfellow, B.; Sumbera, M.; Summa, B.; Sun, X.; Sun, Z.; Sun, X. M.; Sun, Y.; Surrow, B.; Svirida, N.; Szelezniak, M. A.; Tang, A. H.; Tang, Z.; Tarnowsky, T.; Tawfik, A. N.; Thomas, J. H.; Timmins, A. R.; Tlusty, D.; Tokarev, M.; Trentalange, S.; Tribble, R. E.; Tribedy, P.; Tripathy, S. K.; Trzeciak, B. A.; Tsai, O. D.; Ullrich, T.; Underwood, D. G.; Upsal, I.; Van Buren, G.; van Nieuwenhuizen, G.; Vandenbroucke, M.; Varma, R.; Vasiliev, A. N.; Vertesi, R.; Videbæk, F.; Viyogi, Y. P.; Vokal, S.; Voloshin, S. A.; Vossen, A.; Wang, G.; Wang, Y.; Wang, F.; Wang, Y.; Wang, H.; Wang, J. S.; Webb, J. C.; Webb, G.; Wen, L.; Westfall, G. D.; Wieman, H.; Wissink, S. W.; Witt, R.; Wu, Y. F.; Xiao, Z. G.; Xie, W.; Xin, K.; Xu, Q. H.; Xu, Z.; Xu, H.; Xu, N.; Xu, Y. F.; Yang, Q.; Yang, Y.; Yang, S.; Yang, Y.; Yang, C.; Ye, Z.; Yepes, P.; Yi, L.; Yip, K.; Yoo, I.-K.; Yu, N.; Zbroszczyk, H.; Zha, W.; Zhang, X. P.; Zhang, J.; Zhang, Y.; Zhang, J.; Zhang, J. B.; Zhang, S.; Zhang, Z.; Zhao, J.; Zhong, C.; Zhou, L.; Zhu, X.; Zoulkarneeva, Y.; Zyzak, M.; STAR Collaboration

    2015-12-01

    We report the observation of transverse polarization-dependent azimuthal correlations in charged pion pair production with the STAR experiment in p↑+p collisions at RHIC. These correlations directly probe quark transversity distributions. We measure signals in excess of 5 standard deviations at high transverse momenta, at high pseudorapidities η >0.5 , and for pair masses around the mass of the ρ meson. This is the first direct transversity measurement in p +p collisions.

  6. Mediating electrostatic binding of 1-butyl-3-methylimidazolium chloride to enzyme surfaces improves conformational stability.

    PubMed

    Nordwald, Erik M; Kaar, Joel L

    2013-08-01

    We have recently developed a general approach to improve the utility of enzymes in ionic liquids (ILs) via tuning of the ratio of enzyme-containing positive to negative surface charges. In this work, the impact of enzyme surface charge ratio on the biophysical interaction of 1-butyl-3-methylimidazolium chloride ([BMIM][Cl]) with chymotrypsin and lipase was investigated to understand this approach at the molecular level. Results of fluorescence quenching assays indicated that the extent of binding of the [BMIM] cation decreased (7- and 3.5-fold for chymotrypsin and lipase, respectively) as a function of increasing ratio of positive to negative surface charges. Conformational stability assays further showed a close correlation between thermodynamic stabilization and enzyme surface charge ratio as well as [BMIM] binding. As evidence of this correlation, succinylation and acetylation resulted in the stabilization of chymotrypsin in 10% (v/v) [BMIM][Cl] by 17.0 and 6.6 kJ/mol, respectively, while cationization destabilized chymotrypsin by 3.6 kJ/mol. Combined, these results indicate that altering the surface charge ratio mediates the organization of IL molecules, namely, [BMIM] and [Cl], around the enzymes. Preferential exclusion of [Cl], in particular, via lowering of the ratio of positive to negative surface charges, correlated with increased enzyme stability. Accordingly, these results more broadly provide insight into the mechanism of stabilization in ILs via charge modification.

  7. A threshold effect for spacecraft charging

    NASA Technical Reports Server (NTRS)

    Olsen, R. C.

    1983-01-01

    The borderline case between no charging and large (kV) negative potentials for eclipse charging events on geosynchronous satellites is investigated, and the dependence of this transition on a threshold energy in the ambient plasma is examined. Data from the Applied Technology Satellite 6 and P78-2 (SCATHA) show that plasma sheet fluxes must extend above 10 keV for these satellites to charge in eclipse. The threshold effect is a result of the shape of the normal secondary yield curve, in particular the high energy crossover, where the secondary yield drops below 1. It is found that a large portion of the ambient electron flux must exceed this energy for a negative current to exist.

  8. Negative Differential Conductance in Polyporphyrin Oligomers with Nonlinear Backbones.

    PubMed

    Kuang, Guowen; Chen, Shi Zhang; Yan, Linghao; Chen, Ke Qiu; Shang, Xuesong; Liu, Pei Nian; Lin, Nian

    2018-01-17

    We study negative differential conductance (NDC) effects in polyporphyrin oligomers with nonlinear backbones. Using a low-temperature scanning tunneling microscope, we selectively controlled the charge transport path in single oligomer wires. We observed robust NDC when charge passed through a T-shape junction, bistable NDC when charge passed through a 90° kink and no NDC when charge passed through a 120° kink. Aided by density functional theory with nonequilibrium Green's functions simulations, we attributed this backbone-dependent NDC to bias-modulated hybridization of the electrode states with the resonant transport molecular orbital. We argue this mechanism is generic in molecular systems, which opens a new route of designing molecular NDC devices.

  9. Identifying Potential Markets for Behind-the-Meter Battery Energy Storage: A Survey of U.S. Demand Charges

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    McLaren, Joyce A; Gagnon, Pieter J; Mullendore, Seth

    This paper presents the first publicly available comprehensive survey of the magnitude of demand charges for commercial customers across the United States -- a key predictor of the financial performance of behind-the-meter battery storage systems. Notably, the analysis estimates that there are nearly 5 million commercial customers in the United States who can subscribe to retail electricity tariffs that have demand charges in excess of $15 per kilowatt (kW), over a quarter of the 18 million commercial customers in total in the United States. While the economic viability of installing battery energy storage must be determined on a case-by-case basis,more » high demand charges are often cited as a critical factor in battery project economics. Increasing use of demand charges in utility tariffs and anticipated future declines in storage costs will only serve to unlock additional markets and strengthen existing ones.« less

  10. Stability of nTiO2 particles and their attachment to sand: Effects of humic acid at different pH.

    PubMed

    Wu, Yang; Cheng, Tao

    2016-01-15

    The fate and transport of nano-scale or micro-scale titanium dioxide particles (nTiO2) in subsurface environments are strongly influenced by the stability of nTiO2 and their attachment to sediment grains. nTiO2 may carry either positive or negative charges in natural water, therefore, environmental factors such as pH, humic substances, and Fe oxyhydroxide coatings on sediment grains, which are known to control the stability and transport of negatively-charged colloids, may influence nTiO2 in different manners. The objective of this study is to investigate the effects of pH and humic acid (HA) on the stability and attachment of nTiO2 to sand at HA concentrations that are relevant to typical groundwater conditions, so that mechanisms that control nTiO2 immobilization and transport in natural systems can be elucidated. Stability and attachment of nTiO2 to quartz sand and Fe oxyhydroxide coated quartz sand are experimentally measured under a range of HA concentrations at pH5 and 9. Results show that at pH5, negatively-charged HA strongly adsorbs to positively-charged nTiO2 and Fe oxyhydroxide, which, at low HA concentrations, partially neutralizes the positive charges on nTiO2 and Fe oxyhydroxide, and therefore decreases the repulsive electrostatic forces between the surfaces, resulting in nTiO2 aggregation and attachment. At high HA concentrations, adsorbed HA reverses the surface charges of nTiO2 and Fe oxyhydroxide, and makes nTiO2 and Fe oxyhydroxide strongly negatively charged, resulting in stable nTiO2 suspension and low nTiO2 attachment. At pH9, HA, nTiO2, and Fe oxyhydroxide are all negatively charged, and HA adsorption is low and does not have a strong impact on the stability and attachment of nTiO2. Overall, this study shows that changes in surface charges of nTiO2 and Fe oxyhydroxide coating caused by HA adsorption is a key factor that influences the stability and attachment of nTiO2. Copyright © 2015 Elsevier B.V. All rights reserved.

  11. Charge-dependent flow and the search for the chiral magnetic wave in Pb-Pb collisions at s N N = 2.76 TeV

    DOE PAGES

    Adam, J.; Adamová, D.; Aggarwal, M. M.; ...

    2016-04-08

    We report on measurements of a charge-dependent flow using a novel three-particle correlator with ALICE in Pb-Pb collisions at the CERN Large Hadron Collider (LHC), and discuss the implications for observation of local parity violation and the chiral magnetic wave (CMW) in heavy-ion collisions. Charge-dependent flow is reported for different collision centralities as a function of the event charge asymmetry. While our results are in qualitative agreement with expectations based on the CMW, the nonzero signal observed in higher harmonics correlations indicates a possible significant background contribution. We also present results on a differential correlator, where the flow of positivemore » and negative charges is reported as a function of the mean charge of the particles and their pseudorapidity separation. We argue that this differential correlator is better suited to distinguish the differences in positive and negative charges expected due to the CMW and the background effects, such as local charge conservation coupled with strong radial and anisotropic flow.« less

  12. Charge-dependent flow and the search for the chiral magnetic wave in Pb-Pb collisions at √{sN N}=2.76 TeV

    NASA Astrophysics Data System (ADS)

    Adam, J.; Adamová, D.; Aggarwal, M. M.; Aglieri Rinella, G.; Agnello, M.; Agrawal, N.; Ahammed, Z.; Ahn, S. U.; Aiola, S.; Akindinov, A.; Alam, S. N.; Aleksandrov, D.; Alessandro, B.; Alexandre, D.; Alfaro Molina, R.; Alici, A.; Alkin, A.; Almaraz, J. R. M.; Alme, J.; Alt, T.; Altinpinar, S.; Altsybeev, I.; Alves Garcia Prado, C.; Andrei, C.; Andronic, A.; Anguelov, V.; Anielski, J.; Antičić, T.; Antinori, F.; Antonioli, P.; Aphecetche, L.; Appelshäuser, H.; Arcelli, S.; Arnaldi, R.; Arnold, O. W.; Arsene, I. C.; Arslandok, M.; Audurier, B.; Augustinus, A.; Averbeck, R.; Azmi, M. D.; Badalà, A.; Baek, Y. W.; Bagnasco, S.; Bailhache, R.; Bala, R.; Balasubramanian, S.; Baldisseri, A.; Baral, R. C.; Barbano, A. M.; Barbera, R.; Barile, F.; Barnaföldi, G. G.; Barnby, L. S.; Barret, V.; Bartalini, P.; Barth, K.; Bartke, J.; Bartsch, E.; Basile, M.; Bastid, N.; Basu, S.; Bathen, B.; Batigne, G.; Batista Camejo, A.; Batyunya, B.; Batzing, P. C.; Bearden, I. G.; Beck, H.; Bedda, C.; Behera, N. K.; Belikov, I.; Bellini, F.; Bello Martinez, H.; Bellwied, R.; Belmont, R.; Belmont-Moreno, E.; Belyaev, V.; Benacek, P.; Bencedi, G.; Beole, S.; Berceanu, I.; Bercuci, A.; Berdnikov, Y.; Berenyi, D.; Bertens, R. A.; Berzano, D.; Betev, L.; Bhasin, A.; Bhat, I. R.; Bhati, A. K.; Bhattacharjee, B.; Bhom, J.; Bianchi, L.; Bianchi, N.; Bianchin, C.; Bielčík, J.; Bielčíková, J.; Bilandzic, A.; Biro, G.; Biswas, R.; Biswas, S.; Bjelogrlic, S.; Blair, J. T.; Blau, D.; Blume, C.; Bock, F.; Bogdanov, A.; Bøggild, H.; Boldizsár, L.; Bombara, M.; Book, J.; Borel, H.; Borissov, A.; Borri, M.; Bossú, F.; Botta, E.; Bourjau, C.; Braun-Munzinger, P.; Bregant, M.; Breitner, T.; Broker, T. A.; Browning, T. A.; Broz, M.; Brucken, E. J.; Bruna, E.; Bruno, G. E.; Budnikov, D.; Buesching, H.; Bufalino, S.; Buncic, P.; Busch, O.; Buthelezi, Z.; Butt, J. B.; Buxton, J. T.; Caffarri, D.; Cai, X.; Caines, H.; Calero Diaz, L.; Caliva, A.; Calvo Villar, E.; Camerini, P.; Carena, F.; Carena, W.; Carnesecchi, F.; Castillo Castellanos, J.; Castro, A. J.; Casula, E. A. R.; Ceballos Sanchez, C.; Cerello, P.; Cerkala, J.; Chang, B.; Chapeland, S.; Chartier, M.; Charvet, J. L.; Chattopadhyay, S.; Chattopadhyay, S.; Chauvin, A.; Chelnokov, V.; Cherney, M.; Cheshkov, C.; Cheynis, B.; Chibante Barroso, V.; Chinellato, D. D.; Cho, S.; Chochula, P.; Choi, K.; Chojnacki, M.; Choudhury, S.; Christakoglou, P.; Christensen, C. H.; Christiansen, P.; Chujo, T.; Chung, S. U.; Cicalo, C.; Cifarelli, L.; Cindolo, F.; Cleymans, J.; Colamaria, F.; Colella, D.; Collu, A.; Colocci, M.; Conesa Balbastre, G.; Conesa Del Valle, Z.; Connors, M. E.; Contreras, J. G.; Cormier, T. M.; Corrales Morales, Y.; Cortés Maldonado, I.; Cortese, P.; Cosentino, M. R.; Costa, F.; Crochet, P.; Cruz Albino, R.; Cuautle, E.; Cunqueiro, L.; Dahms, T.; Dainese, A.; Danu, A.; Das, D.; Das, I.; Das, S.; Dash, A.; Dash, S.; de, S.; de Caro, A.; de Cataldo, G.; de Conti, C.; de Cuveland, J.; de Falco, A.; de Gruttola, D.; De Marco, N.; de Pasquale, S.; Deisting, A.; Deloff, A.; Dénes, E.; Deplano, C.; Dhankher, P.; di Bari, D.; di Mauro, A.; di Nezza, P.; Diaz Corchero, M. A.; Dietel, T.; Dillenseger, P.; Divià, R.; Djuvsland, Ø.; Dobrin, A.; Domenicis Gimenez, D.; Dönigus, B.; Dordic, O.; Drozhzhova, T.; Dubey, A. K.; Dubla, A.; Ducroux, L.; Dupieux, P.; Ehlers, R. J.; Elia, D.; Endress, E.; Engel, H.; Epple, E.; Erazmus, B.; Erdemir, I.; Erhardt, F.; Espagnon, B.; Estienne, M.; Esumi, S.; Eum, J.; Evans, D.; Evdokimov, S.; Eyyubova, G.; Fabbietti, L.; Fabris, D.; Faivre, J.; Fantoni, A.; Fasel, M.; Feldkamp, L.; Feliciello, A.; Feofilov, G.; Ferencei, J.; Fernández Téllez, A.; Ferreiro, E. G.; Ferretti, A.; Festanti, A.; Feuillard, V. J. G.; Figiel, J.; Figueredo, M. A. S.; Filchagin, S.; Finogeev, D.; Fionda, F. M.; Fiore, E. M.; Fleck, M. G.; Floris, M.; Foertsch, S.; Foka, P.; Fokin, S.; Fragiacomo, E.; Francescon, A.; Frankenfeld, U.; Fronze, G. G.; Fuchs, U.; Furget, C.; Furs, A.; Fusco Girard, M.; Gaardhøje, J. J.; Gagliardi, M.; Gago, A. M.; Gallio, M.; Gangadharan, D. R.; Ganoti, P.; Gao, C.; Garabatos, C.; Garcia-Solis, E.; Gargiulo, C.; Gasik, P.; Gauger, E. F.; Germain, M.; Gheata, A.; Gheata, M.; Ghosh, P.; Ghosh, S. K.; Gianotti, P.; Giubellino, P.; Giubilato, P.; Gladysz-Dziadus, E.; Glässel, P.; Goméz Coral, D. M.; Gomez Ramirez, A.; Gonzalez, V.; González-Zamora, P.; Gorbunov, S.; Görlich, L.; Gotovac, S.; Grabski, V.; Grachov, O. A.; Graczykowski, L. K.; Graham, K. L.; Grelli, A.; Grigoras, A.; Grigoras, C.; Grigoriev, V.; Grigoryan, A.; Grigoryan, S.; Grinyov, B.; Grion, N.; Gronefeld, J. M.; Grosse-Oetringhaus, J. F.; Grossiord, J.-Y.; Grosso, R.; Guber, F.; Guernane, R.; Guerzoni, B.; Gulbrandsen, K.; Gunji, T.; Gupta, A.; Gupta, R.; Haake, R.; Haaland, Ø.; Hadjidakis, C.; Haiduc, M.; Hamagaki, H.; Hamar, G.; Hamon, J. C.; Harris, J. W.; Harton, A.; Hatzifotiadou, D.; Hayashi, S.; Heckel, S. T.; Helstrup, H.; Herghelegiu, A.; Herrera Corral, G.; Hess, B. A.; Hetland, K. F.; Hillemanns, H.; Hippolyte, B.; Horak, D.; Hosokawa, R.; Hristov, P.; Huang, M.; Humanic, T. J.; Hussain, N.; Hussain, T.; Hutter, D.; Hwang, D. S.; Ilkaev, R.; Inaba, M.; Incani, E.; Ippolitov, M.; Irfan, M.; Ivanov, M.; Ivanov, V.; Izucheev, V.; Jacazio, N.; Jacobs, P. M.; Jadhav, M. B.; Jadlovska, S.; Jadlovsky, J.; Jahnke, C.; Jakubowska, M. J.; Jang, H. J.; Janik, M. A.; Jayarathna, P. H. S. Y.; Jena, C.; Jena, S.; Jimenez Bustamante, R. T.; Jones, P. G.; Jung, H.; Jusko, A.; Kalinak, P.; Kalweit, A.; Kamin, J.; Kang, J. H.; Kaplin, V.; Kar, S.; Karasu Uysal, A.; Karavichev, O.; Karavicheva, T.; Karayan, L.; Karpechev, E.; Kebschull, U.; Keidel, R.; Keijdener, D. L. D.; Keil, M.; Mohisin Khan, M.; Khan, P.; Khan, S. A.; Khanzadeev, A.; Kharlov, Y.; Kileng, B.; Kim, D. W.; Kim, D. J.; Kim, D.; Kim, H.; Kim, J. S.; Kim, M.; Kim, M.; Kim, S.; Kim, T.; Kirsch, S.; Kisel, I.; Kiselev, S.; Kisiel, A.; Kiss, G.; Klay, J. L.; Klein, C.; Klein, J.; Klein-Bösing, C.; Klewin, S.; Kluge, A.; Knichel, M. L.; Knospe, A. G.; Kobdaj, C.; Kofarago, M.; Kollegger, T.; Kolojvari, A.; Kondratiev, V.; Kondratyeva, N.; Kondratyuk, E.; Konevskikh, A.; Kopcik, M.; Kour, M.; Kouzinopoulos, C.; Kovalenko, O.; Kovalenko, V.; Kowalski, M.; Koyithatta Meethaleveedu, G.; Králik, I.; Kravčáková, A.; Kretz, M.; Krivda, M.; Krizek, F.; Kryshen, E.; Krzewicki, M.; Kubera, A. M.; Kučera, V.; Kuhn, C.; Kuijer, P. G.; Kumar, A.; Kumar, J.; Kumar, L.; Kumar, S.; Kurashvili, P.; Kurepin, A.; Kurepin, A. B.; Kuryakin, A.; Kweon, M. J.; Kwon, Y.; La Pointe, S. L.; La Rocca, P.; Ladron de Guevara, P.; Lagana Fernandes, C.; Lakomov, I.; Langoy, R.; Lara, C.; Lardeux, A.; Lattuca, A.; Laudi, E.; Lea, R.; Leardini, L.; Lee, G. R.; Lee, S.; Lehas, F.; Lemmon, R. C.; Lenti, V.; Leogrande, E.; León Monzón, I.; León Vargas, H.; Leoncino, M.; Lévai, P.; Li, S.; Li, X.; Lien, J.; Lietava, R.; Lindal, S.; Lindenstruth, V.; Lippmann, C.; Lisa, M. A.; Ljunggren, H. M.; Lodato, D. F.; Loenne, P. I.; Loginov, V.; Loizides, C.; Lopez, X.; López Torres, E.; Lowe, A.; Luettig, P.; Lunardon, M.; Luparello, G.; Lutz, T. H.; Maevskaya, A.; Mager, M.; Mahajan, S.; Mahmood, S. M.; Maire, A.; Majka, R. D.; Malaev, M.; Maldonado Cervantes, I.; Malinina, L.; Mal'Kevich, D.; Malzacher, P.; Mamonov, A.; Manko, V.; Manso, F.; Manzari, V.; Marchisone, M.; Mareš, J.; Margagliotti, G. V.; Margotti, A.; Margutti, J.; Marín, A.; Markert, C.; Marquard, M.; Martin, N. A.; Martin Blanco, J.; Martinengo, P.; Martínez, M. I.; Martínez García, G.; Martinez Pedreira, M.; Mas, A.; Masciocchi, S.; Masera, M.; Masoni, A.; Massacrier, L.; Mastroserio, A.; Matyja, A.; Mayer, C.; Mazer, J.; Mazzoni, M. A.; McDonald, D.; Meddi, F.; Melikyan, Y.; Menchaca-Rocha, A.; Meninno, E.; Mercado Pérez, J.; Meres, M.; Miake, Y.; Mieskolainen, M. M.; Mikhaylov, K.; Milano, L.; Milosevic, J.; Minervini, L. M.; Mischke, A.; Mishra, A. N.; Miśkowiec, D.; Mitra, J.; Mitu, C. M.; Mohammadi, N.; Mohanty, B.; Molnar, L.; Montaño Zetina, L.; Montes, E.; Moreira de Godoy, D. A.; Moreno, L. A. P.; Moretto, S.; Morreale, A.; Morsch, A.; Muccifora, V.; Mudnic, E.; Mühlheim, D.; Muhuri, S.; Mukherjee, M.; Mulligan, J. D.; Munhoz, M. G.; Munzer, R. H.; Murakami, H.; Murray, S.; Musa, L.; Musinsky, J.; Naik, B.; Nair, R.; Nandi, B. K.; Nania, R.; Nappi, E.; Naru, M. U.; Natal da Luz, H.; Nattrass, C.; Navarro, S. R.; Nayak, K.; Nayak, R.; Nayak, T. K.; Nazarenko, S.; Nedosekin, A.; Nellen, L.; Ng, F.; Nicassio, M.; Niculescu, M.; Niedziela, J.; Nielsen, B. S.; Nikolaev, S.; Nikulin, S.; Nikulin, V.; Noferini, F.; Nomokonov, P.; Nooren, G.; Noris, J. C. C.; Norman, J.; Nyanin, A.; Nystrand, J.; Oeschler, H.; Oh, S.; Oh, S. K.; Ohlson, A.; Okatan, A.; Okubo, T.; Olah, L.; Oleniacz, J.; Oliveira da Silva, A. C.; Oliver, M. H.; Onderwaater, J.; Oppedisano, C.; Orava, R.; Ortiz Velasquez, A.; Oskarsson, A.; Otwinowski, J.; Oyama, K.; Ozdemir, M.; Pachmayer, Y.; Pagano, P.; Paić, G.; Pal, S. K.; Pan, J.; Pandey, A. K.; Papcun, P.; Papikyan, V.; Pappalardo, G. S.; Pareek, P.; Park, W. J.; Parmar, S.; Passfeld, A.; Paticchio, V.; Patra, R. N.; Paul, B.; Pei, H.; Peitzmann, T.; Pereira da Costa, H.; Peresunko, D.; Pérez Lara, C. E.; Perez Lezama, E.; Peskov, V.; Pestov, Y.; Petráček, V.; Petrov, V.; Petrovici, M.; Petta, C.; Piano, S.; Pikna, M.; Pillot, P.; Pimentel, L. O. D. L.; Pinazza, O.; Pinsky, L.; Piyarathna, D. B.; Płoskoń, M.; Planinic, M.; Pluta, J.; Pochybova, S.; Podesta-Lerma, P. L. M.; Poghosyan, M. G.; Polichtchouk, B.; Poljak, N.; Poonsawat, W.; Pop, A.; Porteboeuf-Houssais, S.; Porter, J.; Pospisil, J.; Prasad, S. K.; Preghenella, R.; Prino, F.; Pruneau, C. A.; Pshenichnov, I.; Puccio, M.; Puddu, G.; Pujahari, P.; Punin, V.; Putschke, J.; Qvigstad, H.; Rachevski, A.; Raha, S.; Rajput, S.; Rak, J.; Rakotozafindrabe, A.; Ramello, L.; Rami, F.; Raniwala, R.; Raniwala, S.; Räsänen, S. S.; Rascanu, B. T.; Rathee, D.; Read, K. F.; Redlich, K.; Reed, R. J.; Rehman, A.; Reichelt, P.; Reidt, F.; Ren, X.; Renfordt, R.; Reolon, A. R.; Reshetin, A.; Revol, J.-P.; Reygers, K.; Riabov, V.; Ricci, R. A.; Richert, T.; Richter, M.; Riedler, P.; Riegler, W.; Riggi, F.; Ristea, C.; Rocco, E.; Rodríguez Cahuantzi, M.; Rodriguez Manso, A.; Røed, K.; Rogochaya, E.; Rohr, D.; Röhrich, D.; Romita, R.; Ronchetti, F.; Ronflette, L.; Rosnet, P.; Rossi, A.; Roukoutakis, F.; Roy, A.; Roy, C.; Roy, P.; Rubio Montero, A. J.; Rui, R.; Russo, R.; Ryabinkin, E.; Ryabov, Y.; Rybicki, A.; Sadovsky, S.; Šafařík, K.; Sahlmuller, B.; Sahoo, P.; Sahoo, R.; Sahoo, S.; Sahu, P. K.; Saini, J.; Sakai, S.; Saleh, M. A.; Salzwedel, J.; Sambyal, S.; Samsonov, V.; Šándor, L.; Sandoval, A.; Sano, M.; Sarkar, D.; Sarma, P.; Scapparone, E.; Scarlassara, F.; Schiaua, C.; Schicker, R.; Schmidt, C.; Schmidt, H. R.; Schuchmann, S.; Schukraft, J.; Schulc, M.; Schuster, T.; Schutz, Y.; Schwarz, K.; Schweda, K.; Scioli, G.; Scomparin, E.; Scott, R.; Šefčík, M.; Seger, J. E.; Sekiguchi, Y.; Sekihata, D.; Selyuzhenkov, I.; Senosi, K.; Senyukov, S.; Serradilla, E.; Sevcenco, A.; Shabanov, A.; Shabetai, A.; Shadura, O.; Shahoyan, R.; Shangaraev, A.; Sharma, A.; Sharma, M.; Sharma, M.; Sharma, N.; Shigaki, K.; Shtejer, K.; Sibiriak, Y.; Siddhanta, S.; Sielewicz, K. M.; Siemiarczuk, T.; Silvermyr, D.; Silvestre, C.; Simatovic, G.; Simonetti, G.; Singaraju, R.; Singh, R.; Singha, S.; Singhal, V.; Sinha, B. C.; Sinha, T.; Sitar, B.; Sitta, M.; Skaali, T. B.; Slupecki, M.; Smirnov, N.; Snellings, R. J. M.; Snellman, T. W.; Søgaard, C.; Song, J.; Song, M.; Song, Z.; Soramel, F.; Sorensen, S.; de Souza, R. D.; Sozzi, F.; Spacek, M.; Spiriti, E.; Sputowska, I.; Spyropoulou-Stassinaki, M.; Stachel, J.; Stan, I.; Stankus, P.; Stefanek, G.; Stenlund, E.; Steyn, G.; Stiller, J. H.; Stocco, D.; Strmen, P.; Suaide, A. A. P.; Sugitate, T.; Suire, C.; Suleymanov, M.; Suljic, M.; Sultanov, R.; Šumbera, M.; Szabo, A.; Szanto de Toledo, A.; Szarka, I.; Szczepankiewicz, A.; Szymanski, M.; Tabassam, U.; Takahashi, J.; Tambave, G. J.; Tanaka, N.; Tangaro, M. A.; Tarhini, M.; Tariq, M.; Tarzila, M. G.; Tauro, A.; Tejeda Muñoz, G.; Telesca, A.; Terasaki, K.; Terrevoli, C.; Teyssier, B.; Thäder, J.; Thomas, D.; Tieulent, R.; Timmins, A. R.; Toia, A.; Trogolo, S.; Trombetta, G.; Trubnikov, V.; Trzaska, W. H.; Tsuji, T.; Tumkin, A.; Turrisi, R.; Tveter, T. S.; Ullaland, K.; Uras, A.; Usai, G. L.; Utrobicic, A.; Vajzer, M.; Vala, M.; Valencia Palomo, L.; Vallero, S.; van der Maarel, J.; van Hoorne, J. W.; van Leeuwen, M.; Vanat, T.; Vande Vyvre, P.; Varga, D.; Vargas, A.; Vargyas, M.; Varma, R.; Vasileiou, M.; Vasiliev, A.; Vauthier, A.; Vechernin, V.; Veen, A. M.; Veldhoen, M.; Velure, A.; Venaruzzo, M.; Vercellin, E.; Vergara Limón, S.; Vernet, R.; Verweij, M.; Vickovic, L.; Viesti, G.; Viinikainen, J.; Vilakazi, Z.; Villalobos Baillie, O.; Villatoro Tello, A.; Vinogradov, A.; Vinogradov, L.; Vinogradov, Y.; Virgili, T.; Vislavicius, V.; Viyogi, Y. P.; Vodopyanov, A.; Völkl, M. A.; Voloshin, K.; Voloshin, S. A.; Volpe, G.; von Haller, B.; Vorobyev, I.; Vranic, D.; Vrláková, J.; Vulpescu, B.; Wagner, B.; Wagner, J.; Wang, H.; Wang, M.; Watanabe, D.; Watanabe, Y.; Weber, M.; Weber, S. G.; Weiser, D. F.; Wessels, J. P.; Westerhoff, U.; Whitehead, A. M.; Wiechula, J.; Wikne, J.; Wilde, M.; Wilk, G.; Wilkinson, J.; Williams, M. C. S.; Windelband, B.; Winn, M.; Yaldo, C. G.; Yang, H.; Yang, P.; Yano, S.; Yasar, C.; Yin, Z.; Yokoyama, H.; Yoo, I.-K.; Yoon, J. H.; Yurchenko, V.; Yushmanov, I.; Zaborowska, A.; Zaccolo, V.; Zaman, A.; Zampolli, C.; Zanoli, H. J. C.; Zaporozhets, S.; Zardoshti, N.; Zarochentsev, A.; Závada, P.; Zaviyalov, N.; Zbroszczyk, H.; Zgura, I. S.; Zhalov, M.; Zhang, H.; Zhang, X.; Zhang, Y.; Zhang, C.; Zhang, Z.; Zhao, C.; Zhigareva, N.; Zhou, D.; Zhou, Y.; Zhou, Z.; Zhu, H.; Zhu, J.; Zichichi, A.; Zimmermann, A.; Zimmermann, M. B.; Zinovjev, G.; Zyzak, M.; Alice Collaboration

    2016-04-01

    We report on measurements of a charge-dependent flow using a novel three-particle correlator with ALICE in Pb-Pb collisions at the CERN Large Hadron Collider (LHC), and discuss the implications for observation of local parity violation and the chiral magnetic wave (CMW) in heavy-ion collisions. Charge-dependent flow is reported for different collision centralities as a function of the event charge asymmetry. While our results are in qualitative agreement with expectations based on the CMW, the nonzero signal observed in higher harmonics correlations indicates a possible significant background contribution. We also present results on a differential correlator, where the flow of positive and negative charges is reported as a function of the mean charge of the particles and their pseudorapidity separation. We argue that this differential correlator is better suited to distinguish the differences in positive and negative charges expected due to the CMW and the background effects, such as local charge conservation coupled with strong radial and anisotropic flow.

  13. Ionization Efficiency of Doubly Charged Ions Formed from Polyprotic Acids in Electrospray Negative Mode

    NASA Astrophysics Data System (ADS)

    Liigand, Piia; Kaupmees, Karl; Kruve, Anneli

    2016-07-01

    The ability of polyprotic acids to give doubly charged ions in negative mode electrospray was studied and related to physicochemical properties of the acids via linear discriminant analysis (LDA). It was discovered that the compound has to be strongly acidic (low p K a1 and p K a2) and to have high hydrophobicity (log P ow) to become multiply charged. Ability to give multiply charged ions in ESI/MS cannot be directly predicted from the solution phase acidities. Therefore, for the first time, a quantitative model to predict the charge state of the analyte in ESI/MS is proposed and validated for small anions. Also, a model to predict ionization efficiencies of these analytes was developed. Results indicate that acidity of the analyte, its octanol-water partition coefficient, and charge delocalization are important factors that influence ionization efficiencies as well as charge states of the analytes. The pH of the solvent was also found to be an important factor influencing the ionization efficiency of doubly charged ions.

  14. How Do Negative Emotions Impair Self-Control? A Neural Model of Negative Urgency

    PubMed Central

    Chester, David S.; Lynam, Donald R.; Milich, Richard; Powell, David K.; Andersen, Anders H.; DeWall, C. Nathan

    2016-01-01

    Self-control often fails when people experience negative emotions. Negative urgency represents the dispositional tendency to experience such self-control failure in response to negative affect. The neural underpinnings of negative urgency are not fully understood, nor is the more general phenomenon of self-control failure in response to negative emotions. Previous theorizing suggests that an insufficient, inhibitory response from the prefrontal cortex may be the culprit behind such self-control failure. However, we entertained an alternative hypothesis: negative emotions lead to self-control failure because they excessively tax inhibitory regions of the prefrontal cortex. Using fMRI, we compared the neural activity of people high in negative urgency with controls on an emotional, inhibitory Go/No-Go task. While experiencing negative (but not positive or neutral) emotions, participants high in negative urgency showed greater recruitment of inhibitory brain regions than controls. Suggesting a compensatory function, inhibitory accuracy among participants high in negative urgency was associated with greater prefrontal recruitment. Greater activity in the anterior insula on negatively-valenced, inhibitory trials predicted greater substance abuse one month and one year after the MRI scan among individuals high in negative urgency. These results suggest that, among people whose negative emotions often lead to self-control failure, excessive reactivity of the brain’s regulatory resources may be the culprit. PMID:26892861

  15. Whole body acid-base modeling revisited.

    PubMed

    Ring, Troels; Nielsen, Søren

    2017-04-01

    The textbook account of whole body acid-base balance in terms of endogenous acid production, renal net acid excretion, and gastrointestinal alkali absorption, which is the only comprehensive model around, has never been applied in clinical practice or been formally validated. To improve understanding of acid-base modeling, we managed to write up this conventional model as an expression solely on urine chemistry. Renal net acid excretion and endogenous acid production were already formulated in terms of urine chemistry, and we could from the literature also see gastrointestinal alkali absorption in terms of urine excretions. With a few assumptions it was possible to see that this expression of net acid balance was arithmetically identical to minus urine charge, whereby under the development of acidosis, urine was predicted to acquire a net negative charge. The literature already mentions unexplained negative urine charges so we scrutinized a series of seminal papers and confirmed empirically the theoretical prediction that observed urine charge did acquire negative charge as acidosis developed. Hence, we can conclude that the conventional model is problematic since it predicts what is physiologically impossible. Therefore, we need a new model for whole body acid-base balance, which does not have impossible implications. Furthermore, new experimental studies are needed to account for charge imbalance in urine under development of acidosis. Copyright © 2017 the American Physiological Society.

  16. Modeling the total dust production of Enceladus from stochastic charge equilibrium and simulations

    NASA Astrophysics Data System (ADS)

    Meier, Patrick; Motschmann, Uwe; Schmidt, Jürgen; Spahn, Frank; Hill, Thomas W.; Dong, Yaxue; Jones, Geraint H.; Kriegel, Hendrik

    2015-12-01

    Negatively and positively charged nano-sized ice grains were detected in the Enceladus plume by the Cassini Plasma Spectrometer (CAPS). However, no data for uncharged grains, and thus for the total amount of dust, are available. In this paper we estimate this population of uncharged grains based on a model of stochastic charging in thermodynamic equilibrium and on the assumption of quasi-neutrality in the plasma-dust system. This estimation is improved upon by combining simulations of the dust component of the plume and simulations for the plasma environment into one self-consistent model. Calibration of this model with CAPS data provides a total dust production rate of about 12 kg s-1, including larger dust grains up to a few microns in size. We find that the fraction of charged grains dominates over that of the uncharged grains. Moreover, our model reproduces densities of both negatively and positively charged nanograins measured by Cassini CAPS. In Enceladus' plume ion densities up to ~104cm-3 are required by the self-consistent model, resulting in an electron depletion of about 50% in the plasma, because electrons are attached to the negatively charged nanograins. These ion densities correspond to effective ionization rates of about 10-7s-1, which are about two orders of magnitude higher than expected.

  17. Role of electrostatic interactions in the toxicity of titanium dioxide nanoparticles toward Escherichia coli.

    PubMed

    Pagnout, Christophe; Jomini, Stéphane; Dadhwal, Mandeep; Caillet, Céline; Thomas, Fabien; Bauda, Pascale

    2012-04-01

    The increasing production and use of titanium dioxide nanoparticles (NP-TiO(2)) has led to concerns about their possible impact on the environment. Bacteria play crucial roles in ecosystem processes and may be subject to the toxicity of these nanoparticles. In this study, we showed that at low ionic strength, the cell viability of Escherichia coli was more severely affected at pH 5.5 than at pH 7.0 and pH 9.5. At pH 5.5, nanoparticles (positively charged) strongly interacted with the bacterial cells (negatively charged) and accumulated on their surfaces. This phenomenon was observed in a much lower degree at pH 7.0 (NP-TiO(2) neutrally charged and cells negatively charged) and pH 9.5 (both NP-TiO(2) and cells negatively charged). It was also shown that the addition of electrolytes (NaCl, CaCl(2), Na(2)SO(4)) resulted in a gradual reduction of the NP-TiO(2) toxicity at pH 5.5 and an increase in this toxicity at pH 9.5, which was closely related to the reduction of the NP-TiO(2) and bacterial cell electrostatic charges. Crown Copyright © 2011. Published by Elsevier B.V. All rights reserved.

  18. Membrane Permeabilization Induced by Sphingosine: Effect of Negatively Charged Lipids

    PubMed Central

    Jiménez-Rojo, Noemi; Sot, Jesús; Viguera, Ana R.; Collado, M. Isabel; Torrecillas, Alejandro; Gómez-Fernández, J.C.; Goñi, Félix M.; Alonso, Alicia

    2014-01-01

    Sphingosine [(2S, 3R, 4E)-2-amino-4-octadecen-1, 3-diol] is the most common sphingoid long chain base in sphingolipids. It is the precursor of important cell signaling molecules, such as ceramides. In the last decade it has been shown to act itself as a potent metabolic signaling molecule, by activating a number of protein kinases. Moreover, sphingosine has been found to permeabilize phospholipid bilayers, giving rise to vesicle leakage. The present contribution intends to analyze the mechanism by which this bioactive lipid induces vesicle contents release, and the effect of negatively charged bilayers in the release process. Fluorescence lifetime measurements and confocal fluorescence microscopy have been applied to observe the mechanism of sphingosine efflux from large and giant unilamellar vesicles; a graded-release efflux has been detected. Additionally, stopped-flow measurements have shown that the rate of vesicle permeabilization increases with sphingosine concentration. Because at the physiological pH sphingosine has a net positive charge, its interaction with negatively charged phospholipids (e.g., bilayers containing phosphatidic acid together with sphingomyelins, phosphatidylethanolamine, and cholesterol) gives rise to a release of vesicular contents, faster than with electrically neutral bilayers. Furthermore, phosphorous 31-NMR and x-ray data show the capacity of sphingosine to facilitate the formation of nonbilayer (cubic phase) intermediates in negatively charged membranes. The data might explain the pathogenesis of Niemann-Pick type C1 disease. PMID:24940775

  19. Bounding Extreme Spacecraft Charging in the Lunar Environment

    NASA Technical Reports Server (NTRS)

    Minow, Joseph I.; Parker, Linda N.

    2008-01-01

    Robotic and manned spacecraft from the Apollo era demonstrated that the lunar surface in daylight will charge to positive potentials of a few tens of volts because the photoelectron current dominates the charging process. In contrast, potentials of the lunar surface in darkness which were predicted to be on the order of a hundred volts negative in the Apollo era have been shown more recently to reach values of a few hundred volts negative with extremes on the order of a few kilovolts. The recent measurements of night time lunar surface potentials are based on electron beams in the Lunar Prospector Electron Reflectometer data sets interpreted as evidence for secondary electrons generated on the lunar surface accelerated through a plasma sheath from a negatively charged lunar surface. The spacecraft potential was not evaluated in these observations and therefore represents a lower limit to the magnitude of the lunar negative surface potential. This paper will describe a method for obtaining bounds on the magnitude of lunar surface potentials from spacecraft measurements in low lunar orbit based on estimates of the spacecraft potential. We first use Nascap-2k surface charging analyses to evaluate potentials of spacecraft in low lunar orbit and then include the potential drops between the ambient space environment and the spacecraft to the potential drop between the lunar surface and the ambient space environment to estimate the lunar surface potential from the satellite measurements.

  20. Charge Inversion by Electrostatic Complexation: Molecular Dynamics Simulations

    NASA Astrophysics Data System (ADS)

    Faraudo, Jordi; Travesset, Alex

    2007-03-01

    Ions near interfaces play an important role in many biological and physico-chemical processes and exhibit a fascinating diverse range of phenomena. A relevant example is charge inversion, where interfacial charges attract counterions in excess of their own nominal charge, thus leading to an inversion of the sign of the interfacial charge. In this work, we argue that in the case of amphiphilic interfaces, charge inversion can be generated by complexation, that is, electrostatic complexes containing several counterions bound to amphiphilic molecules. The formation of these complexes require the presence at the interface of groups with conformational degrees of freedom with many electronegative atoms. We illustrate this mechanism by analyzing all atomic molecular dynamics simulations of a DMPA (Dimirystoil-Phosphatidic acid) phospholipid monolayer in contact with divalent counterions. The results are found to be in agreement with recent experimental results on Langmuir monolayers. We also discuss the implications for biological systems, as Phosphatidic acid is emerging as a key signaling phospholipid.

  1. Surface charge effects in protein adsorption on nanodiamonds

    NASA Astrophysics Data System (ADS)

    Aramesh, M.; Shimoni, O.; Ostrikov, K.; Prawer, S.; Cervenka, J.

    2015-03-01

    Understanding the interaction of proteins with charged diamond nanoparticles is of fundamental importance for diverse biomedical applications. Here we present a thorough study of protein binding, adsorption kinetics and structure on strongly positively (hydrogen-terminated) and negatively (oxygen-terminated) charged nanodiamond particles using a quartz crystal microbalance by dissipation and infrared spectroscopy. By using two model proteins (bovine serum albumin and lysozyme) of different properties (charge, molecular weight and rigidity), the main driving mechanism responsible for the protein binding to the charged nanoparticles was identified. Electrostatic interactions were found to dominate the protein adsorption dynamics, attachment and conformation. We developed a simple electrostatic model that can qualitatively explain the observed adsorption behaviour based on charge-induced pH modifications near the charged nanoparticle surfaces. Under neutral conditions, the local pH around the positively and negatively charged nanodiamonds becomes very high (11-12) and low (1-3) respectively, which has a profound impact on the protein charge, hydration and affinity to the nanodiamonds. Small proteins (lysozyme) were found to form multilayers with significant conformational changes to screen the surface charge, while larger proteins (albumin) formed monolayers with minor conformational changes. The findings of this study provide a step forward toward understanding and eventually predicting nanoparticle interactions with biofluids.Understanding the interaction of proteins with charged diamond nanoparticles is of fundamental importance for diverse biomedical applications. Here we present a thorough study of protein binding, adsorption kinetics and structure on strongly positively (hydrogen-terminated) and negatively (oxygen-terminated) charged nanodiamond particles using a quartz crystal microbalance by dissipation and infrared spectroscopy. By using two model proteins (bovine serum albumin and lysozyme) of different properties (charge, molecular weight and rigidity), the main driving mechanism responsible for the protein binding to the charged nanoparticles was identified. Electrostatic interactions were found to dominate the protein adsorption dynamics, attachment and conformation. We developed a simple electrostatic model that can qualitatively explain the observed adsorption behaviour based on charge-induced pH modifications near the charged nanoparticle surfaces. Under neutral conditions, the local pH around the positively and negatively charged nanodiamonds becomes very high (11-12) and low (1-3) respectively, which has a profound impact on the protein charge, hydration and affinity to the nanodiamonds. Small proteins (lysozyme) were found to form multilayers with significant conformational changes to screen the surface charge, while larger proteins (albumin) formed monolayers with minor conformational changes. The findings of this study provide a step forward toward understanding and eventually predicting nanoparticle interactions with biofluids. Electronic supplementary information (ESI) available: The FTIR spectrum of nanodiamonds, QCM-D profiles of 50 nm nanodiamond adsorption on silica surfaces, QCM-D profiles of protein desorption after rinsing with water (rinsing experiment) and the full FTIR spectrum of proteins before and after adsorption on ND particles. See DOI: 10.1039/c5nr00250h

  2. Charge Induced Dynamics of Water in a Graphene–Mica Slit Pore

    PubMed Central

    2017-01-01

    We use atomic force microscopy to in situ investigate the dynamic behavior of confined water at the interface between graphene and mica. The graphene is either uncharged, negatively charged, or positively charged. At high humidity, a third water layer will intercalate between graphene and mica. When graphene is negatively charged, the interface fills faster with a complete three layer water film, compared to uncharged graphene. As charged positively, the third water layer dewets the interface, either by evaporation into the ambient or by the formation of three-dimensional droplets under the graphene, on top of the bilayer. Our experimental findings reveal novel phenomena of water at the nanoscale, which are interesting from a fundamental point of view and demonstrate the direct control over the wetting properties of the graphene/water interface. PMID:28985466

  3. Negative Charge Neutralization in the Loops and Turns of Outer Membrane Phospholipase A Impacts Folding Hysteresis at Neutral pH.

    PubMed

    McDonald, Sarah K; Fleming, Karen G

    2016-11-08

    Hysteresis in equilibrium protein folding titrations is an experimental barrier that must be overcome to extract meaningful thermodynamic quantities. Traditional approaches to solving this problem involve testing a spectrum of solution conditions to find ones that achieve path independence. Through this procedure, a specific pH of 3.8 was required to achieve path independence for the water-to-bilayer equilibrium folding of outer membrane protein OmpLA. We hypothesized that the neutralization of negatively charged side chains (Asp and Glu) at pH 3.8 could be the physical basis for path-independent folding at this pH. To test this idea, we engineered variants of OmpLA with Asp → Asn and Glu → Gln mutations to neutralize the negative charges within various regions of the protein and tested for reversible folding at neutral pH. Although not fully resolved, our results show that these mutations in the periplasmic turns and extracellular loops are responsible for 60% of the hysteresis in wild-type folding. Overall, our study suggests that negative charges impact the folding hysteresis in outer membrane proteins and their neutralization may aid in protein engineering applications.

  4. Positive and negative contribution to birefringence in a family of carbonates: A Born effective charges analysis

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Jing, Qun; Yang, Guang; Hou, Juan

    It is an important topic to investigate the birefringence and reveal the contribution from ions to birefringence because it plays an important role in nonlinear optical materials. In this paper, the birefringence of carbonates with coplanar CO{sub 3} groups were investigated using the first-principles method. The results show that the lead carbonates exhibit relative large birefringence. After detailed investigate the electronic structures, and Born effective charges, the authors find out that anisotropic electron distribution in the CO{sub 3} groups and Pb atoms give positive contribution, while the negative contribution was found from fluorine atoms, meanwhile the Ca, Mg, and Cdmore » atoms give very small contribution to birefringence. - Graphical abstract: Using the DFT and Born effective charges, the birefringence and the contribution of ions were investigated, the positive and negative contribution was found from Pb and F ions, respectively. - Highlights: • Optical properties and Born effective charges of carbonates are investigated. • Lead carbonates exhibit relative large birefringence. • Coplanar CO{sub 3} groups and Pb atoms give positive contribution. • F atoms give negative contribution. • Ca, Mg, and Cd atoms give very small contribution.« less

  5. The influence of ligand charge and length on the assembly of Brome mosaic virus derived virus-like particles with magnetic core

    NASA Astrophysics Data System (ADS)

    Mieloch, Adam A.; Krecisz, Monika; Rybka, Jakub D.; Strugała, Aleksander; Krupiński, Michał; Urbanowicz, Anna; Kozak, Maciej; Skalski, Bohdan; Figlerowicz, Marek; Giersig, Michael

    2018-03-01

    Virus-like particles (VLPs) have sparked a great interest in the field of nanobiotechnology and nanomedicine. The introduction of superparamagnetic nanoparticles (SPIONs) as a core, provides potential use of VLPs in the hyperthermia therapy, MRI contrast agents and magnetically-powered delivery agents. Magnetite NPs also provide a significant improvement in terms of VLPs stability. Moreover employing viral structural proteins as self-assembling units has opened a new paths for targeted therapy, drug delivery systems, vaccines design, and many more. In many cases, the self-assembly of a virus strongly depends on electrostatic interactions between positively charged groups of the capsid proteins and negatively charged nucleic acid. This phenomenon imposes the negative net charge as a key requirement for the core nanoparticle. In our experiments, Brome mosaic virus (BMV) capsid proteins isolated from infected plants Hordeum vulgare were used. Superparamagnetic iron oxide nanoparticles (Fe3O4) with 15 nm in diameter were synthesized by thermal decomposition and functionalized with COOH-PEG-PL polymer or dihexadecylphosphate (DHP) in order to provide water solubility and negative charge required for the assembly. Nanoparticles were characterized by Transmission Electron Microscopy (TEM), Dynamic Light Scattering (DLS), Zeta Potential, Fourier Transformed Infrared Spectroscopy (FTIR) and Superconducting Quantum Interference Device (SQUID) magnetometry. TEM and DLS study were conducted to verify VLPs creation. This study demonstrates that the increase of negative surface charge is not a sufficient factor determining successful assembly. Additional steric interactions provided by longer ligands are crucial for the assembly of BMV SPION VLPs and may enhance the colloidal stability.

  6. The influence of PAMAM dendrimers surface groups on their interaction with porcine pepsin.

    PubMed

    Ciolkowski, Michal; Rozanek, Monika; Bryszewska, Maria; Klajnert, Barbara

    2013-10-01

    In this study the ability of three polyamidoamine (PAMAM) dendrimers with different surface charge (positive, neutral and negative) to interact with a negatively charged protein (porcine pepsin) was examined. It was shown that the dendrimer with a positively charged surface (G4 PAMAM-NH2), as well as the dendrimer with a neutral surface (G4 PAMAM-OH), were able to inhibit enzymatic activity of pepsin. It was also found that these dendrimers act as mixed partially non-competitive pepsin inhibitors. The negatively charged dendrimer (G3.5 PAMAM-COOH) was not able to inhibit the enzymatic activity of pepsin, probably due to the electrostatic repulsion between this dendrimer and the protein. No correlation between changes in enzymatic activity of pepsin and alterations in CD spectrum of the protein was observed. It indicates that the interactions between dendrimers and porcine pepsin are complex, multidirectional and not dependent only on disturbances of the secondary structure. © 2013.

  7. Comparative experimental study of gas evolution and gas consumption reactions in sealed Ni-Cd and Ni-MH cells

    NASA Astrophysics Data System (ADS)

    Cha, Chuansin; Yu, Jingxian; Zhang, Jixiao

    The behavior of the sealed Ni-Cd and Ni-MH systems are compared experimentally with regard to their ability to consume gaseous products generated during the overcharge stage of these systems. It was found that the Ni-Cd system could only consume oxygen, while the Ni-MH system possesses the additional ability to adsorb hydrogen and to catalyze the recombination reaction of hydrogen and oxygen. The internal pressure within both sealed Ni-Cd cells and sealed Ni-MH cells can be kept well under control during the charge/overcharge processes if the rate of overcharge is not too high and if there is sufficient surplus of charging capacity at the negative electrodes. However, the internal pressure can rise to dangerously high levels if the rate of overcharge is too high or there is a deficiency of the charging capacity at the negative electrodes. The various factors that may affect the surplus of charging capacity of the negative electrodes are also discussed.

  8. Error processing and response inhibition in excessive computer game players: an event-related potential study.

    PubMed

    Littel, Marianne; van den Berg, Ivo; Luijten, Maartje; van Rooij, Antonius J; Keemink, Lianne; Franken, Ingmar H A

    2012-09-01

    Excessive computer gaming has recently been proposed as a possible pathological illness. However, research on this topic is still in its infancy and underlying neurobiological mechanisms have not yet been identified. The determination of underlying mechanisms of excessive gaming might be useful for the identification of those at risk, a better understanding of the behavior and the development of interventions. Excessive gaming has been often compared with pathological gambling and substance use disorder. Both disorders are characterized by high levels of impulsivity, which incorporates deficits in error processing and response inhibition. The present study aimed to investigate error processing and response inhibition in excessive gamers and controls using a Go/NoGo paradigm combined with event-related potential recordings. Results indicated that excessive gamers show reduced error-related negativity amplitudes in response to incorrect trials relative to correct trials, implying poor error processing in this population. Furthermore, excessive gamers display higher levels of self-reported impulsivity as well as more impulsive responding as reflected by less behavioral inhibition on the Go/NoGo task. The present study indicates that excessive gaming partly parallels impulse control and substance use disorders regarding impulsivity measured on the self-reported, behavioral and electrophysiological level. Although the present study does not allow drawing firm conclusions on causality, it might be that trait impulsivity, poor error processing and diminished behavioral response inhibition underlie the excessive gaming patterns observed in certain individuals. They might be less sensitive to negative consequences of gaming and therefore continue their behavior despite adverse consequences. © 2012 The Authors, Addiction Biology © 2012 Society for the Study of Addiction.

  9. 24 CFR 202.12 - Title II.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ...) General requirements—(i) Prohibition against excess variation. The customary lending practices of a mortgagee for its single family insured mortgages shall not provide for a variation in mortgage charge rates... section. (ii) Customary lending practices. The customary lending practices of a mortgagee include all...

  10. 46 CFR 78.55-1 - Master and chief engineer responsible.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... OPERATIONS Carrying of Excess Steam § 78.55-1 Master and chief engineer responsible. It shall be the duty of the master and the engineer in charge of the boilers of any vessel to require that a steam pressure is...

  11. Video, LMA and ULF observations of a negative gigantic jet in North Texas

    NASA Astrophysics Data System (ADS)

    Bruning, E. C.; Cummer, S.; Palivec, K.; Lyons, W. A.; Chmielewski, V.; MacGorman, D. R.

    2017-12-01

    On 8 September 2016 at 0125:38 UTC video of a negative gigantic jet was captured from Hawley, TX. VHF Lightning Mapping Arrays in West Texas and Oklahoma also observed the parent flash (duration of about 1 s) and, for the first time, mapped dozens of points along ascending negative leaders, lasting about 50 ms, which extended well above cloud top to about 35 km MSL altitude. A few well-located VHF sources were also detected near 50 km. Together, the video and VHF observations provide additional confirmation of the altitude at which the leader-to-streamer transition takes place in gigantic jet discharges. ULF magnetic field data from the Duke iCMC network show a current excursion associated with the onset of the upward movement of negative charge and leaders in the VHF. As the gigantic jet reached its full height, current spiked to 80 kA, followed by several hundred milliseconds of continuing current of 10-20 kA. Total charge moment change was about 6000 C km. The storm complex produced predominantly negative large charge moment change events, which is characteristic of storms that produce negative gigantic jets.

  12. [Sorption of microorganisms by fiber materials].

    PubMed

    Nikovskaia, G N; Gordienko, A S; Globa, L I

    1986-01-01

    Candida guilliermondii and Escherichia coli cells were adsorbed on glass and basalt fibres with a similar specific surface, but with a different charge. The quantity of adsorbed microorganisms did not depend on the type and charge of a fibre surface. However, cells were adsorbed faster and more firmly on positively charged and uncharged fibres than on negatively charged fibres.

  13. Electron Excess Doping and Effective Schottky Barrier Reduction on the MoS2/h-BN Heterostructure.

    PubMed

    Joo, Min-Kyu; Moon, Byoung Hee; Ji, Hyunjin; Han, Gang Hee; Kim, Hyun; Lee, Gwanmu; Lim, Seong Chu; Suh, Dongseok; Lee, Young Hee

    2016-10-12

    Layered hexagonal boron nitride (h-BN) thin film is a dielectric that surpasses carrier mobility by reducing charge scattering with silicon oxide in diverse electronics formed with graphene and transition metal dichalcogenides. However, the h-BN effect on electron doping concentration and Schottky barrier is little known. Here, we report that use of h-BN thin film as a substrate for monolayer MoS 2 can induce ∼6.5 × 10 11 cm -2 electron doping at room temperature which was determined using theoretical flat band model and interface trap density. The saturated excess electron concentration of MoS 2 on h-BN was found to be ∼5 × 10 13 cm -2 at high temperature and was significantly reduced at low temperature. Further, the inserted h-BN enables us to reduce the Coulombic charge scattering in MoS 2 /h-BN and lower the effective Schottky barrier height by a factor of 3, which gives rise to four times enhanced the field-effect carrier mobility and an emergence of metal-insulator transition at a much lower charge density of ∼1.0 × 10 12 cm -2 (T = 25 K). The reduced effective Schottky barrier height in MoS 2 /h-BN is attributed to the decreased effective work function of MoS 2 arisen from h-BN induced n-doping and the reduced effective metal work function due to dipole moments originated from fixed charges in SiO 2 .

  14. An alternative approach to charge transport in semiconducting electrodes

    NASA Technical Reports Server (NTRS)

    Thomchick, J.; Buoncristiani, A. M.

    1980-01-01

    The excess-carrier charge transport through the space-charge region of a semiconducting electrode is analyzed by a technique known as the flux method. In this approach reflection and transmission coefficients appropriate for a sheet of uniform semiconducting material describe its transport properties. A review is presented of the flux method showing that the results for a semiconductor electrode reduce in a limiting case to those previously found by Gaertner if the depletion layer is treated as a perfectly transmitting medium in which scattering and recombination are ignored. Then, in the framework of the flux method the depletion layer is considered more realistically by explicitly taking into account scattering and recombination processes which occur in this region.

  15. Search for High-Mass States with One Lepton Plus Missing Transverse Momentum in Proton-Proton Collisions at $\\sqrt{s} with the ATLAS Detector

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Aad, Georges; Abbott, Brad; Abdallah, Jalal

    2012-06-20

    The ATLAS detector is used to search for high-mass states, such as heavy charged gauge bosons (W{prime},W*), decaying to a charged lepton (electron or muon) and a neutrino. Results are presented based on the analysis of ppcollisions at a center-of-mass energy of 7 TeV corresponding to an integrated luminosity of 36 pb{sup -1}. No excess beyond standard model expectations is observed. A W{prime} with sequential standard model couplings is excluded at 95% confidence level for masses below 1.49 TeV, and a W* (charged chiral boson) for masses below 1.35 TeV.

  16. Search for high-mass states with one lepton plus missing transverse momentum in proton-proton collisions at √{ s} = 7 TeV with the ATLAS detector

    NASA Astrophysics Data System (ADS)

    Aad, G.; Abbott, B.; Abdallah, J.; Abdelalim, A. A.; Abdesselam, A.; Abdinov, O.; Abi, B.; Abolins, M.; Abramowicz, H.; Abreu, H.; Acerbi, E.; Acharya, B. S.; Adams, D. L.; Addy, T. N.; Adelman, J.; Aderholz, M.; Adomeit, S.; Adragna, P.; Adye, T.; Aefsky, S.; Aguilar-Saavedra, J. A.; Aharrouche, M.; Ahlen, S. P.; Ahles, F.; Ahmad, A.; Ahsan, M.; Aielli, G.; Akdogan, T.; Åkesson, T. P. A.; Akimoto, G.; Akimov, A. V.; Akiyama, A.; Alam, M. S.; Alam, M. A.; Albrand, S.; Aleksa, M.; Aleksandrov, I. N.; Aleppo, M.; Alessandria, F.; Alexa, C.; Alexander, G.; Alexandre, G.; Alexopoulos, T.; Alhroob, M.; Ali, S.; Aliev, M.; Alimonti, G.; Alison, J.; Aliyev, M.; Allport, P. P.; Allwood-Spiers, S. E.; Almond, J.; Aloisio, A.; Alon, R.; Alonso, A.; Alviggi, M. G.; Amako, K.; Amaral, P.; Amelung, C.; Ammosov, V. V.; Amorim, A.; Amorós, G.; Amram, N.; Anastopoulos, C.; Andeen, T.; Anders, C. F.; Anderson, K. J.; Andreazza, A.; Andrei, V.; Andrieux, M.-L.; Anduaga, X. S.; Angerami, A.; Anghinolfi, F.; Anjos, N.; Annovi, A.; Antonaki, A.; Antonelli, M.; Antonelli, S.; Antonov, A.; Antos, J.; Anulli, F.; Aoun, S.; Bella, L. Aperio; Apolle, R.; Arabidze, G.; Aracena, I.; Arai, Y.; Arce, A. T. H.; Archambault, J. P.; Arfaoui, S.; Arguin, J.-F.; Arik, E.; Arik, M.; Armbruster, A. J.; Arnaez, O.; Arnault, C.; Artamonov, A.; Artoni, G.; Arutinov, D.; Asai, S.; Asfandiyarov, R.; Ask, S.; Åsman, B.; Asquith, L.; Assamagan, K.; Astbury, A.; Astvatsatourov, A.; Atoian, G.; Aubert, B.; Auerbach, B.; Auge, E.; Augsten, K.; Aurousseau, M.; Austin, N.; Avramidou, R.; Axen, D.; Ay, C.; Azuelos, G.; Azuma, Y.; Baak, M. A.; Baccaglioni, G.; Bacci, C.; Bach, A. M.; Bachacou, H.; Bachas, K.; Bachy, G.; Backes, M.; Backhaus, M.; Badescu, E.; Bagnaia, P.; Bahinipati, S.; Bai, Y.; Bailey, D. C.; Bain, T.; Baines, J. T.; Baker, O. K.; Baker, M. D.; Baker, S.; Baltasar Dos Santos Pedrosa, F.; Banas, E.; Banerjee, P.; Banerjee, Sw.; Banfi, D.; Bangert, A.; Bansal, V.; Bansil, H. S.; Barak, L.; Baranov, S. P.; Barashkou, A.; Barbaro Galtieri, A.; Barber, T.; Barberio, E. L.; Barberis, D.; Barbero, M.; Bardin, D. Y.; Barillari, T.; Barisonzi, M.; Barklow, T.; Barlow, N.; Barnett, B. M.; Barnett, R. M.; Baroncelli, A.; Barr, A. J.; Barreiro, F.; Barreiro Guimarães da Costa, J.; Barrillon, P.; Bartoldus, R.; Barton, A. E.; Bartsch, D.; Bates, R. L.; Batkova, L.; Batley, J. R.; Battaglia, A.; Battistin, M.; Battistoni, G.; Bauer, F.; Bawa, H. S.; Beare, B.; Beau, T.; Beauchemin, P. H.; Beccherle, R.; Bechtle, P.; Beck, H. P.; Beckingham, M.; Becks, K. H.; Beddall, A. J.; Beddall, A.; Bednyakov, V. A.; Bee, C.; Begel, M.; Behar Harpaz, S.; Behera, P. K.; Beimforde, M.; Belanger-Champagne, C.; Bell, P. J.; Bell, W. H.; Bella, G.; Bellagamba, L.; Bellina, F.; Bellomo, G.; Bellomo, M.; Belloni, A.; Beloborodova, O.; Belotskiy, K.; Beltramello, O.; Ben Ami, S.; Benary, O.; Benchekroun, D.; Benchouk, C.; Bendel, M.; Benedict, B. H.; Benekos, N.; Benhammou, Y.; Benjamin, D. P.; Benoit, M.; Bensinger, J. R.; Benslama, K.; Bentvelsen, S.; Berge, D.; Bergeaas Kuutmann, E.; Berger, N.; Berghaus, F.; Berglund, E.; Beringer, J.; Bernardet, K.; Bernat, P.; Bernhard, R.; Bernius, C.; Berry, T.; Bertin, A.; Bertinelli, F.; Bertolucci, F.; Besana, M. I.; Besson, N.; Bethke, S.; Bhimji, W.; Bianchi, R. M.; Bianco, M.; Biebel, O.; Bieniek, S. P.; Biesiada, J.; Biglietti, M.; Bilokon, H.; Bindi, M.; Binet, S.; Bingul, A.; Bini, C.; Biscarat, C.; Bitenc, U.; Black, K. M.; Blair, R. E.; Blanchard, J.-B.; Blanchot, G.; Blocker, C.; Blocki, J.; Blondel, A.; Blum, W.; Blumenschein, U.; Bobbink, G. J.; Bobrovnikov, V. B.; Bocci, A.; Boddy, C. R.; Boehler, M.; Boek, J.; Boelaert, N.; Böser, S.; Bogaerts, J. A.; Bogdanchikov, A.; Bogouch, A.; Bohm, C.; Boisvert, V.; Bold, T.; Boldea, V.; Bona, M.; Bondarenko, V. G.; Boonekamp, M.; Boorman, G.; Booth, C. N.; Booth, P.; Bordoni, S.; Borer, C.; Borisov, A.; Borissov, G.; Borjanovic, I.; Borroni, S.; Bos, K.; Boscherini, D.; Bosman, M.; Boterenbrood, H.; Botterill, D.; Bouchami, J.; Boudreau, J.; Bouhova-Thacker, E. V.; Boulahouache, C.; Bourdarios, C.; Bousson, N.; Boveia, A.; Boyd, J.; Boyko, I. R.; Bozhko, N. I.; Bozovic-Jelisavcic, I.; Bracinik, J.; Braem, A.; Brambilla, E.; Branchini, P.; Brandenburg, G. W.; Brandt, A.; Brandt, G.; Brandt, O.; Bratzler, U.; Brau, B.; Brau, J. E.; Braun, H. M.; Brelier, B.; Bremer, J.; Brenner, R.; Bressler, S.; Breton, D.; Brett, N. D.; Bright-Thomas, P. G.; Britton, D.; Brochu, F. M.; Brock, I.; Brock, R.; Brodbeck, T. J.; Brodet, E.; Broggi, F.; Bromberg, C.; Brooijmans, G.; Brooks, W. K.; Brown, G.; Brubaker, E.; Bruckman de Renstrom, P. A.; Bruncko, D.; Bruneliere, R.; Brunet, S.; Bruni, A.; Bruni, G.; Bruschi, M.; Buanes, T.; Bucci, F.; Buchanan, J.; Buchanan, N. J.; Buchholz, P.; Buckingham, R. M.; Buckley, A. G.; Buda, S. I.; Budagov, I. A.; Budick, B.; Büscher, V.; Bugge, L.; Buira-Clark, D.; Buis, E. J.; Bulekov, O.; Bunse, M.; Buran, T.; Burckhart, H.; Burdin, S.; Burgess, T.; Burke, S.; Busato, E.; Bussey, P.; Buszello, C. P.; Butin, F.; Butler, B.; Butler, J. M.; Buttar, C. M.; Butterworth, J. M.; Buttinger, W.; Byatt, T.; Cabrera Urbán, S.; Caccia, M.; Caforio, D.; Cakir, O.; Calafiura, P.; Calderini, G.; Calfayan, P.; Calkins, R.; Caloba, L. P.; Caloi, R.; Calvet, D.; Calvet, S.; Toro, R. Camacho; Camard, A.; Camarri, P.; Cambiaghi, M.; Cameron, D.; Cammin, J.; Campana, S.; Campanelli, M.; Canale, V.; Canelli, F.; Canepa, A.; Cantero, J.; Capasso, L.; Capeans Garrido, M. D. M.; Caprini, I.; Caprini, M.; Capriotti, D.; Capua, M.; Caputo, R.; Caramarcu, C.; Cardarelli, R.; Carli, T.; Carlino, G.; Carminati, L.; Caron, B.; Caron, S.; Carpentieri, C.; Carrillo Montoya, G. D.; Carter, A. A.; Carter, J. R.; Carvalho, J.; Casadei, D.; Casado, M. P.; Cascella, M.; Caso, C.; Castaneda Hernandez, A. M.; Castaneda-Miranda, E.; Castillo Gimenez, V.; Castro, N. F.; Cataldi, G.; Cataneo, F.; Catinaccio, A.; Catmore, J. R.; Cattai, A.; Cattani, G.; Caughron, S.; Cauz, D.; Cavallari, A.; Cavalleri, P.; Cavalli, D.; Cavalli-Sforza, M.; Cavasinni, V.; Cazzato, A.; Ceradini, F.; Cerqueira, A. S.; Cerri, A.; Cerrito, L.; Cerutti, F.; Cetin, S. A.; Cevenini, F.; Chafaq, A.; Chakraborty, D.; Chan, K.; Chapleau, B.; Chapman, J. D.; Chapman, J. W.; Chareyre, E.; Charlton, D. G.; Chavda, V.; Cheatham, S.; Chekanov, S.; Chekulaev, S. V.; Chelkov, G. A.; Chelstowska, M. A.; Chen, C.; Chen, H.; Chen, L.; Chen, S.; Chen, T.; Chen, X.; Cheng, S.; Cheplakov, A.; Chepurnov, V. F.; Cherkaoui El Moursli, R.; Chernyatin, V.; Cheu, E.; Cheung, S. L.; Chevalier, L.; Chevallier, F.; Chiefari, G.; Chikovani, L.; Childers, J. T.; Chilingarov, A.; Chiodini, G.; Chizhov, M. V.; Choudalakis, G.; Chouridou, S.; Christidi, I. A.; Christov, A.; Chromek-Burckhart, D.; Chu, M. L.; Chudoba, J.; Ciapetti, G.; Ciba, K.; Ciftci, A. K.; Ciftci, R.; Cinca, D.; Cindro, V.; Ciobotaru, M. D.; Ciocca, C.; Ciocio, A.; Cirilli, M.; Ciubancan, M.; Clark, A.; Clark, P. J.; Cleland, W.; Clemens, J. C.; Clement, B.; Clement, C.; Clifft, R. W.; Coadou, Y.; Cobal, M.; Coccaro, A.; Cochran, J.; Coe, P.; Cogan, J. G.; Coggeshall, J.; Cogneras, E.; Cojocaru, C. D.; Colas, J.; Colijn, A. P.; Collard, C.; Collins, N. J.; Collins-Tooth, C.; Collot, J.; Colon, G.; Coluccia, R.; Comune, G.; Conde Muiño, P.; Coniavitis, E.; Conidi, M. C.; Consonni, M.; Constantinescu, S.; Conta, C.; Conventi, F.; Cook, J.; Cooke, M.; Cooper, B. D.; Cooper-Sarkar, A. M.; Cooper-Smith, N. J.; Copic, K.; Cornelissen, T.; Corradi, M.; Corriveau, F.; Cortes-Gonzalez, A.; Cortiana, G.; Costa, G.; Costa, M. J.; Costanzo, D.; Costin, T.; Côté, D.; Coura Torres, R.; Courneyea, L.; Cowan, G.; Cowden, C.; Cox, B. E.; Cranmer, K.; Crescioli, F.; Cristinziani, M.; Crosetti, G.; Crupi, R.; Crépé-Renaudin, S.; Cuenca Almenar, C.; Cuhadar Donszelmann, T.; Cuneo, S.; Curatolo, M.; Curtis, C. J.; Cwetanski, P.; Czirr, H.; Czyczula, Z.; D'Auria, S.; D'Onofrio, M.; D'Orazio, A.; da Rocha Gesualdi Mello, A.; da Silva, P. V. M.; da Via, C.; Dabrowski, W.; Dahlhoff, A.; Dai, T.; Dallapiccola, C.; Dallison, S. J.; Dam, M.; Dameri, M.; Damiani, D. S.; Danielsson, H. O.; Dankers, R.; Dannheim, D.; Dao, V.; Darbo, G.; Darlea, G. L.; Daum, C.; Dauvergne, J. P.; Davey, W.; Davidek, T.; Davidson, N.; Davidson, R.; Davies, M.; Davison, A. R.; Dawe, E.; Dawson, I.; Dawson, J. W.; Daya, R. K.; de, K.; de Asmundis, R.; de Castro, S.; de Castro Faria Salgado, P. E.; de Cecco, S.; de Graat, J.; de Groot, N.; de Jong, P.; de La Taille, C.; de la Torre, H.; de Lotto, B.; de Mora, L.; de Nooij, L.; de Oliveira Branco, M.; de Pedis, D.; de Saintignon, P.; de Salvo, A.; de Sanctis, U.; de Santo, A.; de Vivie de Regie, J. B.; Dean, S.; Dedovich, D. V.; Degenhardt, J.; Dehchar, M.; Deile, M.; Del Papa, C.; Del Peso, J.; Del Prete, T.; Dell'Acqua, A.; Dell'Asta, L.; Della Pietra, M.; Della Volpe, D.; Delmastro, M.; Delpierre, P.; Delruelle, N.; Delsart, P. A.; Deluca, C.; Demers, S.; Demichev, M.; Demirkoz, B.; Deng, J.; Denisov, S. P.; Derendarz, D.; Derkaoui, J. E.; Derue, F.; Dervan, P.; Desch, K.; Devetak, E.; Deviveiros, P. O.; Dewhurst, A.; Dewilde, B.; Dhaliwal, S.; Dhullipudi, R.; di Ciaccio, A.; di Ciaccio, L.; di Girolamo, A.; di Girolamo, B.; di Luise, S.; di Mattia, A.; di Micco, B.; di Nardo, R.; di Simone, A.; di Sipio, R.; Diaz, M. A.; Diblen, F.; Diehl, E. B.; Dietl, H.; Dietrich, J.; Dietzsch, T. A.; Diglio, S.; Dindar Yagci, K.; Dingfelder, J.; Dionisi, C.; Dita, P.; Dita, S.; Dittus, F.; Djama, F.; Djilkibaev, R.; Djobava, T.; Do Vale, M. A. B.; Do Valle Wemans, A.; Doan, T. K. O.; Dobbs, M.; Dobinson, R.; Dobos, D.; Dobson, E.; Dobson, M.; Dodd, J.; Dogan, O. B.; Doglioni, C.; Doherty, T.; Doi, Y.; Dolejsi, J.; Dolenc, I.; Dolezal, Z.; Dolgoshein, B. A.; Dohmae, T.; Donadelli, M.; Donega, M.; Donini, J.; Dopke, J.; Doria, A.; Dos Anjos, A.; Dosil, M.; Dotti, A.; Dova, M. T.; Dowell, J. D.; Doxiadis, A. D.; Doyle, A. T.; Drasal, Z.; Drees, J.; Dressnandt, N.; Drevermann, H.; Driouichi, C.; Dris, M.; Drohan, J. G.; Dubbert, J.; Dubbs, T.; Dube, S.; Duchovni, E.; Duckeck, G.; Dudarev, A.; Dudziak, F.; Dührssen, M.; Duerdoth, I. P.; Duflot, L.; Dufour, M.-A.; Dunford, M.; Duran Yildiz, H.; Duxfield, R.; Dwuznik, M.; Dydak, F.; Dzahini, D.; Düren, M.; Ebenstein, W. L.; Ebke, J.; Eckert, S.; Eckweiler, S.; Edmonds, K.; Edwards, C. A.; Efthymiopoulos, I.; Ehrenfeld, W.; Ehrich, T.; Eifert, T.; Eigen, G.; Einsweiler, K.; Eisenhandler, E.; Ekelof, T.; El Kacimi, M.; Ellert, M.; Elles, S.; Ellinghaus, F.; Ellis, K.; Ellis, N.; Elmsheuser, J.; Elsing, M.; Ely, R.; Emeliyanov, D.; Engelmann, R.; Engl, A.; Epp, B.; Eppig, A.; Erdmann, J.; Ereditato, A.; Eriksson, D.; Ernst, J.; Ernst, M.; Ernwein, J.; Errede, D.; Errede, S.; Ertel, E.; Escalier, M.; Escobar, C.; Espinal Curull, X.; Esposito, B.; Etienne, F.; Etienvre, A. I.; Etzion, E.; Evangelakou, D.; Evans, H.; Fabbri, L.; Fabre, C.; Facius, K.; Fakhrutdinov, R. M.; Falciano, S.; Falou, A. C.; Fang, Y.; Fanti, M.; Farbin, A.; Farilla, A.; Farley, J.; Farooque, T.; Farrington, S. M.; Farthouat, P.; Fasching, D.; Fassnacht, P.; Fassouliotis, D.; Fatholahzadeh, B.; Favareto, A.; Fayard, L.; Fazio, S.; Febbraro, R.; Federic, P.; Fedin, O. L.; Fedorko, I.; Fedorko, W.; Fehling-Kaschek, M.; Feligioni, L.; Fellmann, D.; Felzmann, C. U.; Feng, C.; Feng, E. J.; Fenyuk, A. B.; Ferencei, J.; Ferland, J.; Fernandes, B.; Fernando, W.; Ferrag, S.; Ferrando, J.; Ferrara, V.; Ferrari, A.; Ferrari, P.; Ferrari, R.; Ferrer, A.; Ferrer, M. L.; Ferrere, D.; Ferretti, C.; Ferretto Parodi, A.; Fiascaris, M.; Fiedler, F.; Filipčič, A.; Filippas, A.; Filthaut, F.; Fincke-Keeler, M.; Fiolhais, M. C. N.; Fiorini, L.; Firan, A.; Fischer, G.; Fischer, P.; Fisher, M. J.; Fisher, S. M.; Flammer, J.; Flechl, M.; Fleck, I.; Fleckner, J.; Fleischmann, P.; Fleischmann, S.; Flick, T.; Flores Castillo, L. R.; Flowerdew, M. J.; Föhlisch, F.; Fokitis, M.; Fonseca Martin, T.; Forbush, D. A.; Formica, A.; Forti, A.; Fortin, D.; Foster, J. M.; Fournier, D.; Foussat, A.; Fowler, A. J.; Fowler, K.; Fox, H.; Francavilla, P.; Franchino, S.; Francis, D.; Frank, T.; Franklin, M.; Franz, S.; Fraternali, M.; Fratina, S.; French, S. T.; Froeschl, R.; Froidevaux, D.; Frost, J. A.; Fukunaga, C.; Fullana Torregrosa, E.; Fuster, J.; Gabaldon, C.; Gabizon, O.; Gadfort, T.; Gadomski, S.; Gagliardi, G.; Gagnon, P.; Galea, C.; Gallas, E. J.; Gallas, M. V.; Gallo, V.; Gallop, B. J.; Gallus, P.; Galyaev, E.; Gan, K. K.; Gao, Y. S.; Gapienko, V. A.; Gaponenko, A.; Garberson, F.; Garcia-Sciveres, M.; García, C.; García Navarro, J. E.; Gardner, R. W.; Garelli, N.; Garitaonandia, H.; Garonne, V.; Garvey, J.; Gatti, C.; Gaudio, G.; Gaumer, O.; Gaur, B.; Gauthier, L.; Gavrilenko, I. L.; Gay, C.; Gaycken, G.; Gayde, J.-C.; Gazis, E. N.; Ge, P.; Gee, C. N. P.; Geerts, D. A. A.; Geich-Gimbel, Ch.; Gellerstedt, K.; Gemme, C.; Gemmell, A.; Genest, M. H.; Gentile, S.; George, M.; George, S.; Gerlach, P.; Gershon, A.; Geweniger, C.; Ghazlane, H.; Ghez, P.; Ghodbane, N.; Giacobbe, B.; Giagu, S.; Giakoumopoulou, V.; Giangiobbe, V.; Gianotti, F.; Gibbard, B.; Gibson, A.; Gibson, S. M.; Gieraltowski, G. F.; Gilbert, L. M.; Gilchriese, M.; Gilewsky, V.; Gillberg, D.; Gillman, A. 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B.; Nicolaidou, R.; Nicolas, L.; Nicquevert, B.; Niedercorn, F.; Nielsen, J.; Niinikoski, T.; Nikiforov, A.; Nikolaenko, V.; Nikolaev, K.; Nikolic-Audit, I.; Nikolopoulos, K.; Nilsen, H.; Nilsson, P.; Ninomiya, Y.; Nisati, A.; Nishiyama, T.; Nisius, R.; Nodulman, L.; Nomachi, M.; Nomidis, I.; Nomoto, H.; Nordberg, M.; Nordkvist, B.; Norton, P. R.; Novakova, J.; Nozaki, M.; Nožička, M.; Nozka, L.; Nugent, I. M.; Nuncio-Quiroz, A.-E.; Nunes Hanninger, G.; Nunnemann, T.; Nurse, E.; Nyman, T.; O'Brien, B. J.; O'Neale, S. W.; O'Neil, D. C.; O'Shea, V.; Oakham, F. G.; Oberlack, H.; Ocariz, J.; Ochi, A.; Oda, S.; Odaka, S.; Odier, J.; Ogren, H.; Oh, A.; Oh, S. H.; Ohm, C. C.; Ohshima, T.; Ohshita, H.; Ohska, T. K.; Ohsugi, T.; Okada, S.; Okawa, H.; Okumura, Y.; Okuyama, T.; Olcese, M.; Olchevski, A. G.; Oliveira, M.; Oliveira Damazio, D.; Oliver Garcia, E.; Olivito, D.; Olszewski, A.; Olszowska, J.; Omachi, C.; Onofre, A.; Onyisi, P. U. E.; Oram, C. J.; Ordonez, G.; Oreglia, M. 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V.; Peng, H.; Pengo, R.; Penson, A.; Penwell, J.; Perantoni, M.; Perez, K.; Perez Cavalcanti, T.; Perez Codina, E.; Pérez García-Estañ, M. T.; Perez Reale, V.; Peric, I.; Perini, L.; Pernegger, H.; Perrino, R.; Perrodo, P.; Persembe, S.; Peshekhonov, V. D.; Peters, O.; Petersen, B. A.; Petersen, J.; Petersen, T. C.; Petit, E.; Petridis, A.; Petridou, C.; Petrolo, E.; Petrucci, F.; Petschull, D.; Petteni, M.; Pezoa, R.; Phan, A.; Phillips, A. W.; Phillips, P. W.; Piacquadio, G.; Piccaro, E.; Piccinini, M.; Pickford, A.; Piec, S. M.; Piegaia, R.; Pilcher, J. E.; Pilkington, A. D.; Pina, J.; Pinamonti, M.; Pinder, A.; Pinfold, J. L.; Ping, J.; Pinto, B.; Pirotte, O.; Pizio, C.; Placakyte, R.; Plamondon, M.; Plano, W. G.; Pleier, M.-A.; Pleskach, A. V.; Poblaguev, A.; Poddar, S.; Podlyski, F.; Poggioli, L.; Poghosyan, T.; Pohl, M.; Polci, F.; Polesello, G.; Policicchio, A.; Polini, A.; Poll, J.; Polychronakos, V.; Pomarede, D. M.; Pomeroy, D.; Pommès, K.; Pontecorvo, L.; Pope, B. G.; Popeneciu, G. A.; Popovic, D. S.; Poppleton, A.; Portell Bueso, X.; Porter, R.; Posch, C.; Pospelov, G. E.; Pospisil, S.; Potrap, I. N.; Potter, C. J.; Potter, C. T.; Poulard, G.; Poveda, J.; Prabhu, R.; Pralavorio, P.; Prasad, S.; Pravahan, R.; Prell, S.; Pretzl, K.; Pribyl, L.; Price, D.; Price, L. E.; Price, M. J.; Prichard, P. M.; Prieur, D.; Primavera, M.; Prokofiev, K.; Prokoshin, F.; Protopopescu, S.; Proudfoot, J.; Prudent, X.; Przysiezniak, H.; Psoroulas, S.; Ptacek, E.; Purdham, J.; Purohit, M.; Puzo, P.; Pylypchenko, Y.; Qian, J.; Qian, Z.; Qin, Z.; Quadt, A.; Quarrie, D. R.; Quayle, W. B.; Quinonez, F.; Raas, M.; Radescu, V.; Radics, B.; Rador, T.; Ragusa, F.; Rahal, G.; Rahimi, A. M.; Rahm, D.; Rajagopalan, S.; Rajek, S.; Rammensee, M.; Rammes, M.; Ramstedt, M.; Randrianarivony, K.; Ratoff, P. N.; Rauscher, F.; Rauter, E.; Raymond, M.; Read, A. L.; Rebuzzi, D. M.; Redelbach, A.; Redlinger, G.; Reece, R.; Reeves, K.; Reichold, A.; Reinherz-Aronis, E.; Reinsch, A.; Reisinger, I.; Reljic, D.; Rembser, C.; Ren, Z. L.; Renaud, A.; Renkel, P.; Rensch, B.; Rescigno, M.; Resconi, S.; Resende, B.; Reznicek, P.; Rezvani, R.; Richards, A.; Richter, R.; Richter-Was, E.; Ridel, M.; Rieke, S.; Rijpstra, M.; Rijssenbeek, M.; Rimoldi, A.; Rinaldi, L.; Rios, R. R.; Riu, I.; Rivoltella, G.; Rizatdinova, F.; Rizvi, E.; Robertson, S. H.; Robichaud-Veronneau, A.; Robinson, D.; Robinson, J. E. M.; Robinson, M.; Robson, A.; Rocha de Lima, J. G.; Roda, C.; Roda Dos Santos, D.; Rodier, S.; Rodriguez, D.; Rodriguez Garcia, Y.; Roe, A.; Roe, S.; Røhne, O.; Rojo, V.; Rolli, S.; Romaniouk, A.; Romanov, V. M.; Romeo, G.; Romero Maltrana, D.; Roos, L.; Ros, E.; Rosati, S.; Rose, M.; Rosenbaum, G. A.; Rosenberg, E. I.; Rosendahl, P. L.; Rosselet, L.; Rossetti, V.; Rossi, E.; Rossi, L. P.; Rossi, L.; Rotaru, M.; Roth, I.; Rothberg, J.; Rottländer, I.; Rousseau, D.; Royon, C. R.; Rozanov, A.; Rozen, Y.; Ruan, X.; Rubinskiy, I.; Ruckert, B.; Ruckstuhl, N.; Rud, V. I.; Rudolph, G.; Rühr, F.; Ruggieri, F.; Ruiz-Martinez, A.; Rulikowska-Zarebska, E.; Rumiantsev, V.; Rumyantsev, L.; Runge, K.; Runolfsson, O.; Rurikova, Z.; Rusakovich, N. A.; Rust, D. R.; Rutherfoord, J. P.; Ruwiedel, C.; Ruzicka, P.; Ryabov, Y. F.; Ryadovikov, V.; Ryan, P.; Rybar, M.; Rybkin, G.; Ryder, N. C.; Rzaeva, S.; Saavedra, A. F.; Sadeh, I.; Sadrozinski, H. F.-W.; Sadykov, R.; Safai Tehrani, F.; Sakamoto, H.; Salamanna, G.; Salamon, A.; Saleem, M.; Salihagic, D.; Salnikov, A.; Salt, J.; Salvachua Ferrando, B. M.; Salvatore, D.; Salvatore, F.; Salzburger, A.; Sampsonidis, D.; Samset, B. H.; Sandaker, H.; Sander, H. G.; Sanders, M. P.; Sandhoff, M.; Sandhu, P.; Sandoval, T.; Sandstroem, R.; Sandvoss, S.; Sankey, D. P. C.; Sansoni, A.; Santamarina Rios, C.; Santoni, C.; Santonico, R.; Santos, H.; Saraiva, J. G.; Sarangi, T.; Sarkisyan-Grinbaum, E.; Sarri, F.; Sartisohn, G.; Sasaki, O.; Sasaki, T.; Sasao, N.; Satsounkevitch, I.; Sauvage, G.; Sauvan, J. B.; Savard, P.; Savinov, V.; Savu, D. O.; Savva, P.; Sawyer, L.; Saxon, D. H.; Says, L. P.; Sbarra, C.; Sbrizzi, A.; Scallon, O.; Scannicchio, D. A.; Schaarschmidt, J.; Schacht, P.; Schäfer, U.; Schaepe, S.; Schaetzel, S.; Schaffer, A. C.; Schaile, D.; Schamberger, R. D.; Schamov, A. G.; Scharf, V.; Schegelsky, V. A.; Scheirich, D.; Scherzer, M. I.; Schiavi, C.; Schieck, J.; Schioppa, M.; Schlenker, S.; Schlereth, J. L.; Schmidt, E.; Schmidt, M. P.; Schmieden, K.; Schmitt, C.; Schmitz, M.; Schöning, A.; Schott, M.; Schouten, D.; Schovancova, J.; Schram, M.; Schroeder, C.; Schroer, N.; Schuh, S.; Schuler, G.; Schultes, J.; Schultz-Coulon, H.-C.; Schulz, H.; Schumacher, J. W.; Schumacher, M.; Schumm, B. A.; Schune, Ph.; Schwanenberger, C.; Schwartzman, A.; Schwemling, Ph.; Schwienhorst, R.; Schwierz, R.; Schwindling, J.; Scott, W. G.; Searcy, J.; Sedykh, E.; Segura, E.; Seidel, S. C.; Seiden, A.; Seifert, F.; Seixas, J. M.; Sekhniaidze, G.; Seliverstov, D. M.; Sellden, B.; Sellers, G.; Seman, M.; Semprini-Cesari, N.; Serfon, C.; Serin, L.; Seuster, R.; Severini, H.; Sevior, M. E.; Sfyrla, A.; Shabalina, E.; Shamim, M.; Shan, L. Y.; Shank, J. T.; Shao, Q. T.; Shapiro, M.; Shatalov, P. B.; Shaver, L.; Shaw, C.; Shaw, K.; Sherman, D.; Sherwood, P.; Shibata, A.; Shimizu, S.; Shimojima, M.; Shin, T.; Shmeleva, A.; Shochet, M. J.; Short, D.; Shupe, M. A.; Sicho, P.; Sidoti, A.; Siebel, A.; Siegert, F.; Siegrist, J.; Sijacki, Dj.; Silbert, O.; Silva, J.; Silver, Y.; Silverstein, D.; Silverstein, S. B.; Simak, V.; Simard, O.; Simic, Lj.; Simion, S.; Simmons, B.; Simonyan, M.; Sinervo, P.; Sinev, N. B.; Sipica, V.; Siragusa, G.; Sisakyan, A. N.; Sivoklokov, S. Yu.; Sjölin, J.; Sjursen, T. B.; Skinnari, L. A.; Skovpen, K.; Skubic, P.; Skvorodnev, N.; Slater, M.; Slavicek, T.; Sliwa, K.; Sloan, T. J.; Sloper, J.; Smakhtin, V.; Smirnov, S. Yu.; Smirnova, L. N.; Smirnova, O.; Smith, B. C.; Smith, D.; Smith, K. M.; Smizanska, M.; Smolek, K.; Snesarev, A. A.; Snow, S. W.; Snow, J.; Snuverink, J.; Snyder, S.; Soares, M.; Sobie, R.; Sodomka, J.; Soffer, A.; Solans, C. A.; Solar, M.; Solc, J.; Soldatov, E.; Soldevila, U.; Solfaroli Camillocci, E.; Solodkov, A. A.; Solovyanov, O. V.; Sondericker, J.; Soni, N.; Sopko, V.; Sopko, B.; Sorbi, M.; Sosebee, M.; Soukharev, A.; Spagnolo, S.; Spanò, F.; Spighi, R.; Spigo, G.; Spila, F.; Spiriti, E.; Spiwoks, R.; Spousta, M.; Spreitzer, T.; Spurlock, B.; St. Denis, R. D.; Stahl, T.; Stahlman, J.; Stamen, R.; Stanecka, E.; Stanek, R. W.; Stanescu, C.; Stapnes, S.; Starchenko, E. A.; Stark, J.; Staroba, P.; Starovoitov, P.; Staude, A.; Stavina, P.; Stavropoulos, G.; Steele, G.; Steinbach, P.; Steinberg, P.; Stekl, I.; Stelzer, B.; Stelzer, H. J.; Stelzer-Chilton, O.; Stenzel, H.; Stevenson, K.; Stewart, G. A.; Stillings, J. A.; Stockmanns, T.; Stockton, M. C.; Stoerig, K.; Stoicea, G.; Stonjek, S.; Strachota, P.; Stradling, A. R.; Straessner, A.; Strandberg, J.; Strandberg, S.; Strandlie, A.; Strang, M.; Strauss, E.; Strauss, M.; Strizenec, P.; Ströhmer, R.; Strom, D. M.; Strong, J. A.; Stroynowski, R.; Strube, J.; Stugu, B.; Stumer, I.; Stupak, J.; Sturm, P.; Soh, D. A.; Su, D.; Subramania, Hs.; Sugaya, Y.; Sugimoto, T.; Suhr, C.; Suita, K.; Suk, M.; Sulin, V. V.; Sultansoy, S.; Sumida, T.; Sun, X.; Sundermann, J. E.; Suruliz, K.; Sushkov, S.; Susinno, G.; Sutton, M. R.; Suzuki, Y.; Sviridov, Yu. M.; Swedish, S.; Sykora, I.; Sykora, T.; Szeless, B.; Sánchez, J.; Ta, D.; Tackmann, K.; Taffard, A.; Tafirout, R.; Taga, A.; Taiblum, N.; Takahashi, Y.; Takai, H.; Takashima, R.; Takeda, H.; Takeshita, T.; Talby, M.; Talyshev, A.; Tamsett, M. C.; Tanaka, J.; Tanaka, R.; Tanaka, S.; Tanaka, S.; Tanaka, Y.; Tani, K.; Tannoury, N.; Tappern, G. P.; Tapprogge, S.; Tardif, D.; Tarem, S.; Tarrade, F.; Tartarelli, G. F.; Tas, P.; Tasevsky, M.; Tassi, E.; Tatarkhanov, M.; Taylor, C.; Taylor, F. E.; Taylor, G. N.; Taylor, W.; Teixeira Dias Castanheira, M.; Teixeira-Dias, P.; Temming, K. K.; Ten Kate, H.; Teng, P. K.; Terada, S.; Terashi, K.; Terron, J.; Terwort, M.; Testa, M.; Teuscher, R. J.; Tevlin, C. M.; Thadome, J.; Therhaag, J.; Theveneaux-Pelzer, T.; Thioye, M.; Thoma, S.; Thomas, J. P.; Thompson, E. N.; Thompson, P. D.; Thompson, P. D.; Thompson, A. S.; Thomson, E.; Thomson, M.; Thun, R. P.; Tic, T.; Tikhomirov, V. O.; Tikhonov, Y. A.; Timmermans, C. J. W. P.; Tipton, P.; Tique Aires Viegas, F. J.; Tisserant, S.; Tobias, J.; Toczek, B.; Todorov, T.; Todorova-Nova, S.; Toggerson, B.; Tojo, J.; Tokár, S.; Tokunaga, K.; Tokushuku, K.; Tollefson, K.; Tomoto, M.; Tompkins, L.; Toms, K.; Tonazzo, A.; Tong, G.; Tonoyan, A.; Topfel, C.; Topilin, N. D.; Torchiani, I.; Torrence, E.; Torró Pastor, E.; Toth, J.; Touchard, F.; Tovey, D. R.; Traynor, D.; Trefzger, T.; Treis, J.; Tremblet, L.; Tricoli, A.; Trigger, I. M.; Trincaz-Duvoid, S.; Trinh, T. N.; Tripiana, M. F.; Triplett, N.; Trischuk, W.; Trivedi, A.; Trocmé, B.; Troncon, C.; Trottier-McDonald, M.; Trzupek, A.; Tsarouchas, C.; Tseng, J. C.-L.; Tsiakiris, M.; Tsiareshka, P. V.; Tsionou, D.; Tsipolitis, G.; Tsiskaridze, V.; Tskhadadze, E. G.; Tsukerman, I. I.; Tsulaia, V.; Tsung, J.-W.; Tsuno, S.; Tsybychev, D.; Tua, A.; Tuggle, J. M.; Turala, M.; Turecek, D.; Turk Cakir, I.; Turlay, E.; Turra, R.; Tuts, P. M.; Tykhonov, A.; Tylmad, M.; Tyndel, M.; Typaldos, D.; Tyrvainen, H.; Tzanakos, G.; Uchida, K.; Ueda, I.; Ueno, R.; Ugland, M.; Uhlenbrock, M.; Uhrmacher, M.; Ukegawa, F.; Unal, G.; Underwood, D. G.; Undrus, A.; Unel, G.; Unno, Y.; Urbaniec, D.; Urkovsky, E.; Urquijo, P.; Urrejola, P.; Usai, G.; Uslenghi, M.; Vacavant, L.; Vacek, V.; Vachon, B.; Vahsen, S.; Valderanis, C.; Valenta, J.; Valente, P.; Valentinetti, S.; Valkar, S.; Valladolid Gallego, E.; Vallecorsa, S.; Valls Ferrer, J. A.; van der Graaf, H.; van der Kraaij, E.; van der Leeuw, R.; van der Poel, E.; van der Ster, D.; van Eijk, B.; van Eldik, N.; van Gemmeren, P.; van Kesteren, Z.; van Vulpen, I.; Vandelli, W.; Vandoni, G.; Vaniachine, A.; Vankov, P.; Vannucci, F.; Varela Rodriguez, F.; Vari, R.; Varnes, E. W.; Varouchas, D.; Vartapetian, A.; Varvell, K. E.; Vassilakopoulos, V. I.; Vazeille, F.; Vegni, G.; Veillet, J. J.; Vellidis, C.; Veloso, F.; Veness, R.; Veneziano, S.; Ventura, A.; Ventura, D.; Venturi, M.; Venturi, N.; Vercesi, V.; Verducci, M.; Verkerke, W.; Vermeulen, J. C.; Vest, A.; Vetterli, M. C.; Vichou, I.; Vickey, T.; Viehhauser, G. H. A.; Viel, S.; Villa, M.; Villaplana Perez, M.; Vilucchi, E.; Vincter, M. G.; Vinek, E.; Vinogradov, V. B.; Virchaux, M.; Viret, S.; Virzi, J.; Vitale, A.; Vitells, O.; Viti, M.; Vivarelli, I.; Vives Vaque, F.; Vlachos, S.; Vlasak, M.; Vlasov, N.; Vogel, A.; Vokac, P.; Volpi, G.; Volpi, M.; Volpini, G.; von der Schmitt, H.; von Loeben, J.; von Radziewski, H.; von Toerne, E.; Vorobel, V.; Vorobiev, A. P.; Vorwerk, V.; Vos, M.; Voss, R.; Voss, T. T.; Vossebeld, J. H.; Vovenko, A. S.; Vranjes, N.; Vranjes Milosavljevic, M.; Vrba, V.; Vreeswijk, M.; Vu Anh, T.; Vuillermet, R.; Vukotic, I.; Wagner, W.; Wagner, P.; Wahlen, H.; Wakabayashi, J.; Walbersloh, J.; Walch, S.; Walder, J.; Walker, R.; Walkowiak, W.; Wall, R.; Waller, P.; Wang, C.; Wang, H.; Wang, J.; Wang, J.; Wang, J. C.; Wang, R.; Wang, S. M.; Warburton, A.; Ward, C. P.; Warsinsky, M.; Watkins, P. M.; Watson, A. T.; Watson, M. F.; Watts, G.; Watts, S.; Waugh, A. T.; Waugh, B. M.; Weber, J.; Weber, M.; Weber, M. S.; Weber, P.; Weidberg, A. R.; Weigell, P.; Weingarten, J.; Weiser, C.; Wellenstein, H.; Wells, P. S.; Wen, M.; Wenaus, T.; Wendler, S.; Weng, Z.; Wengler, T.; Wenig, S.; Wermes, N.; Werner, M.; Werner, P.; Werth, M.; Wessels, M.; Whalen, K.; Wheeler-Ellis, S. J.; Whitaker, S. P.; White, A.; White, M. J.; White, S.; Whitehead, S. R.; Whiteson, D.; Whittington, D.; Wicek, F.; Wicke, D.; Wickens, F. J.; Wiedenmann, W.; Wielers, M.; Wienemann, P.; Wiglesworth, C.; Wiik, L. A. M.; Wijeratne, P. A.; Wildauer, A.; Wildt, M. A.; Wilhelm, I.; Wilkens, H. G.; Will, J. Z.; Williams, E.; Williams, H. H.; Willis, W.; Willocq, S.; Wilson, J. A.; Wilson, M. G.; Wilson, A.; Wingerter-Seez, I.; Winkelmann, S.; Winklmeier, F.; Wittgen, M.; Wolter, M. W.; Wolters, H.; Wooden, G.; Wosiek, B. K.; Wotschack, J.; Woudstra, M. J.; Wraight, K.; Wright, C.; Wrona, B.; Wu, S. L.; Wu, X.; Wu, Y.; Wulf, E.; Wunstorf, R.; Wynne, B. M.; Xaplanteris, L.; Xella, S.; Xie, S.; Xie, Y.; Xu, C.; Xu, D.; Xu, G.; Yabsley, B.; Yamada, M.; Yamamoto, A.; Yamamoto, K.; Yamamoto, S.; Yamamura, T.; Yamaoka, J.; Yamazaki, T.; Yamazaki, Y.; Yan, Z.; Yang, H.; Yang, U. K.; Yang, Y.; Yang, Y.; Yang, Z.; Yanush, S.; Yao, W.-M.; Yao, Y.; Yasu, Y.; Ybeles Smit, G. V.; Ye, J.; Ye, S.; Yilmaz, M.; Yoosoofmiya, R.; Yorita, K.; Yoshida, R.; Young, C.; Youssef, S.; Yu, D.; Yu, J.; Yu, J.; Yuan, L.; Yurkewicz, A.; Zaets, V. G.; Zaidan, R.; Zaitsev, A. M.; Zajacova, Z.; Zalite, Yo. K.; Zanello, L.; Zarzhitsky, P.; Zaytsev, A.; Zeitnitz, C.; Zeller, M.; Zema, P. F.; Zemla, A.; Zendler, C.; Zenin, A. V.; Zenin, O.; Ženiš, T.; Zenonos, Z.; Zenz, S.; Zerwas, D.; Zevi Della Porta, G.; Zhan, Z.; Zhang, D.; Zhang, H.; Zhang, J.; Zhang, X.; Zhang, Z.; Zhao, L.; Zhao, T.; Zhao, Z.; Zhemchugov, A.; Zheng, S.; Zhong, J.; Zhou, B.; Zhou, N.; Zhou, Y.; Zhu, C. G.; Zhu, H.; Zhu, Y.; Zhuang, X.; Zhuravlov, V.; Zieminska, D.; Zilka, B.; Zimmermann, R.; Zimmermann, S.; Zimmermann, S.; Ziolkowski, M.; Zitoun, R.; Živković, L.; Zmouchko, V. V.; Zobernig, G.; Zoccoli, A.; Zolnierowski, Y.; Zsenei, A.; Zur Nedden, M.; Zutshi, V.; Zwalinski, L.; Atlas Collaboration

    2011-06-01

    The ATLAS detector is used to search for high-mass states, such as heavy charged gauge bosons (W‧ ,W*), decaying to a charged lepton (electron or muon) and a neutrino. Results are presented based on the analysis of pp collisions at a center-of-mass energy of 7 TeV corresponding to an integrated luminosity of 36 pb-1. No excess beyond standard model expectations is observed. A W‧ with sequential standard model couplings is excluded at 95% confidence level for masses below 1.49 TeV, and a W* (charged chiral boson) for masses below 1.35 TeV.

  17. Charged-to-neutral correlation at forward rapidity in Au+Au collisions at s NN = 200 GeV

    DOE PAGES

    Adamczyk, L.; Adkins, J. K.; Agakishiev, G.; ...

    2015-03-20

    Event-by-event fluctuations of the ratio of inclusive charged to photon multiplicities at forward rapidity in Au+Au collision at √s NN=200 GeV have been studied. Dominant contribution to such fluctuations is expected to come from correlated production of charged and neutral pions. We search for evidences of dynamical fluctuations of different physical origins. Observables constructed out of moments of multiplicities are used as measures of fluctuations. Mixed events and model calculations are used as baselines. Results are compared to the dynamical net-charge fluctuations measured in the same acceptance. A non-zero statistically significant signal of dynamical fluctuations is observed in excess tomore » the model prediction when charged particles and photons are measured in the same acceptance. Thus, we find that, unlike dynamical net-charge fluctuation, charge-neutral fluctuation is not dominated by correlation due to particle decay. Results are compared to the expectations based on the generic production mechanism of pions due to isospin symmetry, for which no significant (< 1%) deviation is observed.« less

  18. S1-S3 counter charges in the voltage sensor module of a mammalian sodium channel regulate fast inactivation.

    PubMed

    Groome, James R; Winston, Vern

    2013-05-01

    The movement of positively charged S4 segments through the electric field drives the voltage-dependent gating of ion channels. Studies of prokaryotic sodium channels provide a mechanistic view of activation facilitated by electrostatic interactions of negatively charged residues in S1 and S2 segments, with positive counterparts in the S4 segment. In mammalian sodium channels, S4 segments promote domain-specific functions that include activation and several forms of inactivation. We tested the idea that S1-S3 countercharges regulate eukaryotic sodium channel functions, including fast inactivation. Using structural data provided by bacterial channels, we constructed homology models of the S1-S4 voltage sensor module (VSM) for each domain of the mammalian skeletal muscle sodium channel hNaV1.4. These show that side chains of putative countercharges in hNaV1.4 are oriented toward the positive charge complement of S4. We used mutagenesis to define the roles of conserved residues in the extracellular negative charge cluster (ENC), hydrophobic charge region (HCR), and intracellular negative charge cluster (INC). Activation was inhibited with charge-reversing VSM mutations in domains I-III. Charge reversal of ENC residues in domains III (E1051R, D1069K) and IV (E1373K, N1389K) destabilized fast inactivation by decreasing its probability, slowing entry, and accelerating recovery. Several INC mutations increased inactivation from closed states and slowed recovery. Our results extend the functional characterization of VSM countercharges to fast inactivation, and support the premise that these residues play a critical role in domain-specific gating transitions for a mammalian sodium channel.

  19. Molecular understanding of osmosis in semipermeable membranes.

    PubMed

    Raghunathan, A V; Aluru, N R

    2006-07-14

    We investigate single-file osmosis of water through a semipermeable membrane with an uncharged, a positively and a negatively charged nanopore. Molecular dynamics simulations indicate that the osmotic flux through a negatively charged pore (J_) is higher compared to the osmotic flux in a positively charged pore (J+) followed by the osmotic flux in the uncharged pore (J(0)), i.e., J_ > J+ > J(0). The molecular mechanisms governing osmosis, steady state osmosis, and the observed osmotic flux dependence on the nanopore charge are explained by computing all the molecular interactions involved and identifying the molecular interactions that play an important role during and after osmosis. This study helps in a fundamental understanding of osmosis and in the design of advanced nanoporous membranes for various applications of osmosis.

  20. Controlling the electrophoretic mobility of single-walled carbon nanotubes: a comparison of theory and experiment.

    PubMed

    Usrey, Monica L; Nair, Nitish; Agnew, Daniel E; Pina, Cesar F; Strano, Michael S

    2007-07-03

    The electrophoretic mobilities of single-walled carbon nanotubes (SWNTs) in agarose gels subjected to negatively charged covalent functionalization and noncovalent anionic surfactant adsorption are compared using a simplified hydrodynamic model. Net charges are calculated on the basis of estimated friction coefficients for cylindrical rodlike particles. The effects of functionalization with negatively charged 4-hydroxybenzene diazonium and anionic sodium cholate are quantified and compared with model predictions. The adsorption of Na+ counterions into the nonionic surfactant layer adsorbed on SWNTs (Triton-X-405) is shown to induce a positive charge and reverse the mobility under select conditions. This effect has not been identified or quantified for nanoparticle systems and may be important in the processing of these systems.

  1. The effects of vortex like distributed electron in magnetized multi-ion dusty plasmas

    NASA Astrophysics Data System (ADS)

    Haider, Md. Masum; Ferdous, Tahmina; Duha, Syed S.

    2014-09-01

    The nonlinear propagation of small but finite amplitude dust-ion-acoustic solitary waves in a magnetized, collisionless dusty plasma is investigated theoretically. It has been assumed that the electrons are trapped following the vortex-like distribution and that the negatively and positively charged ions are mobile with the presence of charge fluctuating stationary dusts, where ions mass provide the inertia and restoring forces are provided by the thermal pressure of hot electrons. A reductive perturbation method was employed to obtain a modified Korteweg-de Vries (mK-dV) equation for the first-order potential and a stationary solution is obtained. The effect of the presence of trapped electrons, negatively and positively charged ions and arbitrary charged dust grains are discussed.

  2. The Role of Nanoparticle Surface Functionality in the Disruption of Model Cell Membranes

    PubMed Central

    Moghadam, Babak Y.; Hou, Wen-Che; Corredor, Charlie; Westerhoff, Paul; Posner, Jonathan D.

    2012-01-01

    Lipid bilayers are biomembranes common to cellular life and constitute a continuous barrier between cells and their environment. Understanding the interaction of engineered nanomaterials (ENMs) with lipid bilayers is an important step toward predicting subsequent biological effects. In this study, we assess the effect of varying the surface functionality and concentration of 10 nm-diameter gold (Au) and titanium dioxide (TiO2) ENMs on the disruption of negatively charged lipid bilayer vesicles (liposomes) using a dye leakage assay. Our findings show that Au ENMs having both positive and negative surface charge induce leakage that reaches a steady state after several hours. Positively charged particles with identical surface functionality and different core composition show similar leakage effects and result in faster and greater leakage than negatively charged particles, which suggests that surface functionality, not particle core composition, is a critical factor in determining the interaction between ENMs and lipid bilayers. The results suggest that particles permanently adsorb to bilayers and that only one positively charged particle is required to disrupt a liposome and trigger leakage of its entire contents in contrast to mellitin molecules, the most widely studied membrane lytic peptide, which requires hundred of molecules to generate leakage. PMID:22921268

  3. Surface charge effects in protein adsorption on nanodiamonds.

    PubMed

    Aramesh, M; Shimoni, O; Ostrikov, K; Prawer, S; Cervenka, J

    2015-03-19

    Understanding the interaction of proteins with charged diamond nanoparticles is of fundamental importance for diverse biomedical applications. Here we present a thorough study of protein binding, adsorption kinetics and structure on strongly positively (hydrogen-terminated) and negatively (oxygen-terminated) charged nanodiamond particles using a quartz crystal microbalance by dissipation and infrared spectroscopy. By using two model proteins (bovine serum albumin and lysozyme) of different properties (charge, molecular weight and rigidity), the main driving mechanism responsible for the protein binding to the charged nanoparticles was identified. Electrostatic interactions were found to dominate the protein adsorption dynamics, attachment and conformation. We developed a simple electrostatic model that can qualitatively explain the observed adsorption behaviour based on charge-induced pH modifications near the charged nanoparticle surfaces. Under neutral conditions, the local pH around the positively and negatively charged nanodiamonds becomes very high (11-12) and low (1-3) respectively, which has a profound impact on the protein charge, hydration and affinity to the nanodiamonds. Small proteins (lysozyme) were found to form multilayers with significant conformational changes to screen the surface charge, while larger proteins (albumin) formed monolayers with minor conformational changes. The findings of this study provide a step forward toward understanding and eventually predicting nanoparticle interactions with biofluids.

  4. Purposes, Causes and Consequences of Excessive Internet Use among Turkish Adolescents

    ERIC Educational Resources Information Center

    Akar, Filiz

    2015-01-01

    Problem Statement: Excessive internet use, particularly problematic and negative consequences of internet use, is rapidly increasing among children and adolescents throughout the World and in Turkey. While the internet provides potential advantages for users in terms of the academic support, sharing ideas & feelings, and freedom of expression,…

  5. Negative measurement sensitivity values of planar capacitive imaging probes

    NASA Astrophysics Data System (ADS)

    Yin, Xiaokang; Chen, Guoming; Li, Wei; Hutchins, David

    2014-02-01

    The measurement sensitivity distribution of planar capacitive imaging (CI) probes describes how effectively each region in the sensing area is contributing to the measured charge signal on the sensing electrode. It can be used to determine the imaging ability of a CI probe. It is found in previous work that, there are regions in the sensing area where the change of the charge output and the change of targeting physical parameter are of opposite trends. This opposite correlation implies that the measurement sensitivity values in such regions are negative. In this work, the cause of negative sensitivity is discussed. Experiments are also designed and performed so as to verify the existence of negative sensitivity and study the factors that may affect the negative sensitivity distributions.

  6. Assessment and Control of Spacecraft Charging Risks on the International Space Station

    NASA Technical Reports Server (NTRS)

    Koontz, Steve; Edeen, Marybeth; Spetch, William; Dalton, Penni; Keening, Thomas

    2003-01-01

    Electrical interactions between the F2 region ionospheric plasma and the 160V photovoltaic (PV) electrical power system on the International Space Station (ISS) can produce floating potentials (FP) on the ISS conducting structure of greater magnitude than are usually observed on spacecraft in low-Earth orbit. Flight through the geomagnetic field also causes magnetic induction charging of ISS conducting structure. Charging processes resulting from interaction of ISS with auroral electrons may also contribute to charging albeit rarely. The magnitude and frequency of occurrence of possibly hazardous charging events depends on the ISS assembly stage (six more 160V PV arrays will be added to ISS), ISS flight configuration, ISS position (latitude and longitude), and the natural variability in the ionospheric flight environment. At present, ISS is equipped with two plasma contactors designed to control ISS FP to within 40 volts of the ambient F2 plasma. The negative-polarity grounding scheme utilized in the ISS 160V power system leads, naturally, to negative values of ISS FP. A negative ISS structural FP leads to application of electrostatic fields across the dielectrics that separate conducting structure from the ambient F2 plasma, thereby enabling dielectric breakdown and arcing. Degradation of some thermal control coatings and noise in electrical systems can result. Continued review and evaluation of the putative charging hazards, as required by the ISS Program Office, revealed that ISS charging could produce a risk of electric shock to the ISS crew during extra vehicular activity. ISS charging risks are being evaluated in ongoing ISS charging measurements and analysis campaigns. The results of ISS charging measurements are combined with a recently developed detailed model of the ISS charging process and an extensive analysis of historical ionospheric variability data, to assess ISS charging risks using Probabilistic Risk Assessment (PRA) methods. The PRA analysis (estimated frequency of occurrence and severity of the charging hazards) are then used to select the hazard control strategy that provides the best overall safety and mission success environment for ISS and the ISS crew. This paper presents: 1) a summary of ISS spacecraft charging analysis, measurements, observations made to date, 2) plans for future ISS spacecraft charging measurement campaigns, and 3) a detailed discussion of the PRA strategy used to assess ISS spacecraft charging risks and select charging hazard control strategies

  7. Assessment and Control of International Space Station Spacecraft Charging Risks

    NASA Astrophysics Data System (ADS)

    Koontz, S.; Edeen, M.; Spetch, W.; Dalton, P.; Keeping, T.; Minow, J.

    2003-12-01

    Electrical interactions between the F2 region ionospheric plasma and the 160V photovoltaic (PV) electrical power system on the International Space Station (ISS) can produce floating potentials (FP) on ISS conducting structure of greater magnitude than are usually observed on spacecraft in low-Earth orbit. Flight through the geomagnetic field also causes magnetic induction charging of ISS conducting structure. Charging processes resulting from interaction of ISS with auroral electrons may also contribute to charging, albeit rarely. The magnitude and frequency of occurrence of possibly hazardous charging events depends on the ISS assembly stage (six more 160V PV arrays will be added to ISS), ISS flight configuration, ISS position (latitude and longitude), and the natural variability in the ionospheric flight environment. At present, ISS is equipped with two plasma contactors designed to control ISS FP to within 40 volts of the ambient F2 plasma. The negative-polarity grounding scheme utilized in the ISS 160V power system leads, naturally, to negative values of ISS FP. A negative ISS structural FP leads to application of electrostatic fields across the dielectrics that separate conducting structure from the ambient F2 plasma, thereby enabling dielectric breakdown and arcing. Degradation of some thermal control coatings and noise in electrical systems can result. Continued review and evaluation of the putative charging hazards, as required by the ISS Program Office, revealed that ISS charging could produce a risk of electric shock to the ISS crew during extra vehicular activity. ISS charging risks are being evaluated in ongoing ISS charging measurements and analysis campaigns. The results of ISS charging measurements are combined with a recently developed detailed model of the ISS charging process and an extensive analysis of historical ionospheric variability data, to assess ISS charging risks using Probabilistic Risk Assessment (PRA) methods. The PRA analysis (estimated frequency of occurrence and severity of the charging hazards) are then used to select the hazard control strategy that provides the best overall safety and mission success environment for ISS and the ISS crew. This paper presents: 1) a summary of ISS spacecraft charging analysis, measurements, observations made to date, 2) plans for future ISS spacecraft charging measurement campaigns, and 3) a detailed discussion of the PRA strategy used to assess ISS spacecraft charging risks and select charging hazard control strategies.

  8. Protein charge ladders reveal that the net charge of ALS-linked superoxide dismutase can be different in sign and magnitude from predicted values

    PubMed Central

    Shi, Yunhua; Abdolvahabi, Alireza; Shaw, Bryan F

    2014-01-01

    This article utilized “protein charge ladders”—chemical derivatives of proteins with similar structure, but systematically altered net charge—to quantify how missense mutations that cause amyotrophic lateral sclerosis (ALS) affect the net negative charge (Z) of superoxide dismutase-1 (SOD1) as a function of subcellular pH and Zn2+ stoichiometry. Capillary electrophoresis revealed that the net charge of ALS-variant SOD1 can be different in sign and in magnitude—by up to 7.4 units per dimer at lysosomal pH—than values predicted from standard pKa values of amino acids and formal oxidation states of metal ions. At pH 7.4, the G85R, D90A, and G93R substitutions diminished the net negative charge of dimeric SOD1 by up to +2.29 units more than predicted; E100K lowered net charge by less than predicted. The binding of a single Zn2+ to mutant SOD1 lowered its net charge by an additional +2.33 ± 0.01 to +3.18 ± 0.02 units, however, each protein regulated net charge when binding a second, third, or fourth Zn2+ (ΔZ < 0.44 ± 0.07 per additional Zn2+). Both metalated and apo-SOD1 regulated net charge across subcellular pH, without inverting from negative to positive at the theoretical pI. Differential scanning calorimetry, hydrogen-deuterium exchange, and inductively coupled plasma mass spectrometry confirmed that the structure, stability, and metal content of mutant proteins were not significantly affected by lysine acetylation. Measured values of net charge should be used when correlating the biophysical properties of a specific ALS-variant SOD1 protein with its observed aggregation propensity or clinical phenotype. PMID:25052939

  9. Frequency-Dependent Capacitance of Hydrophobic Membranes Containing Fixed Negative Charges

    PubMed Central

    Ilani, Asher

    1968-01-01

    Filters containing fixed negative charges were saturated with hydrophobic solvent and interposed between aqueous solutions. The capacitance of such membranes was measured in the frequency range of 0.05-30 kc. The capacitance increased with decrease in frequency. The frequency dependence of the capacitance was sensitive to nature of the cation present and to salt concentration in the aqueous solution. It is suggested that variation of membrane resistivity in the space charge region of the membrane is responsible for this phenomenon. Possible effects of the potential and counterion concentration profiles at the membrane-water interface are discussed. PMID:5699796

  10. Mortality following blood culture in premature infants: increased with Gram-negative bacteremia and candidemia, but not Gram-positive bacteremia.

    PubMed

    Benjamin, Daniel K; DeLong, Elizabeth; Cotten, Charles M; Garges, Harmony P; Steinbach, William J; Clark, Reese H

    2004-03-01

    To describe survival following nosocomial bloodstream infections and quantify excess mortality associated with positive blood culture. Multicenter cohort study of premature infants. First blood culture was negative for 4648/5497 (78%) of the neonates--390/4648 (8%) died prior to discharge. Mortality prior to discharge was 19% in the 161 infants with Gram-negative rod (GNR) bacteremia, 8% in the 854 neonates with coagulase negative staphylococcus (CONS), 6% in the 169 infants infected with other Gram-positive bacteria (GP-o), and 26% in the 115 neonates with candidemia. The excess 7-day mortality was 0% for Gram-positive organisms and 83% for GNR bacteremia and candidemia. Using negative blood culture as referent, GNR [hazard ratio (HR)=2.61] and candidemia (HR=2.27) were associated with increased mortality; CONS (HR=1.08) and GP-o (HR=0.97) were not. Nosocomial GNR bacteremia and candidemia were associated with increased mortality but Gram-positive bacteremia was not.

  11. Versatile organic (fullerene)-inorganic (CdTe nanoparticle) nanoensembles.

    PubMed

    Guldi, Dirk M; Zilbermann, Israel; Anderson, Greg; Kotov, Nicholas A; Tagmatarchis, Nikos; Prato, Maurizio

    2004-11-10

    Novel organic (positively charged fullerene)-inorganic (negatively charged CdTe nanoparticle) nanoensembles were devised through electrostatic interactions and probed as versatile donor-acceptor hybrids. Photoirradiation of their homogeneous solutions, containing the electrostatically packed components, let to very long-lived (1.3 ms) charge separated states.

  12. Extending the application of deuterium excess as a tracer in surface and groundwaters

    NASA Astrophysics Data System (ADS)

    Hurst, S.; Krishnamurthy, R. V.

    2017-12-01

    Stable isotopes of surface and ground waters provide invaluable information on the processes involved in their genesis. A starting point in these applications is the relationship between hydrogen (δ2H) and oxygen (δ18O), exemplified in the so-called Global Meteoric Water Line where δ2H=8δ18O+10 [1]. From this line Dansgaard [2] defined the parameter deuterium excess where d=δ2H-8δ18O. Generally, the d-excess value is fixed at the source, predominantly the equatorial oceans and retained. At an average humidity of about 85% the expected d-excess value is 10. Deviations indicate secondary changes in the air mass or a water body thus making d-excess a useful geophysical tracer. For instance, evaporation results in a higher d-excess in the vapor. Mixing of this water vapor with overhead air mass results in precipitation exhibiting d-excess values higher than Global Meteoric Water Line [3]. Alternatively, the fraction of liquid remaining will have low d-excess and in extreme cases negative d-excess. In this case a plot of d-excess-δ2H will give a straight line with a negative slope. This can be demonstrated from pan evaporation experiments [4]. Deviation from a perfect straight line on the d-excess-δ2H plot indicates a combination of mixing from various source waters and evaporation. This study will discuss various case studies from multiple environments applying this approach using d-excess. References [1] Craig, H. Standard for Reporting Concentrations of Deuterium and Oxygen-18 in Natural Waters. Science 133, 1833-1834 (1961). [2] Dansgaard, W. Stable isotopes in precipitation. Tellus A 16: 436-468 (1964). [3] Machavaram, M. &, Krishnamurthy, R.V. Earth surface evaporative process: a case study from the Great Lakes region of the United States based on deuterium excess in precipitation. Geochim. et Cosmochem. Acta 59, 4279-4283 (1995). [4] Simpson, H.J., Hamza, M.S., & White, J.W.C. Evaporative enrichment of deuterium and 18O in arid zone irrigation. IAEA, 241-256 (1987).

  13. Nanocomplexes of Photolabile Polyelectrolyte and Upconversion Nanoparticles for Near-Infrared Light-Triggered Payload Release.

    PubMed

    Xiang, Jun; Ge, Feijie; Yu, Bing; Yan, Qiang; Shi, Feng; Zhao, Yue

    2018-06-07

    A new approach to encapsulating charged cargo molecules into a nanovector and subsequently using near-infrared (NIR) light to trigger the release is demonstrated. NIR light-responsive nanovector was prepared through electrostatic interaction-driven complexation between negatively charged silica-coated upconversion nanoparticles (UCNP@silica, 87 nm hydrodynamic diameter, polydispersity index ∼0.05) and a positively charged UV-labile polyelectrolyte bearing pendants of poly(ethylene glycol) and o-nitrobenzyl side groups; whereas charged fluorescein (FLU) was loaded through a co-complexation process. By controlling the amount of polyelectrolyte, UCNP@silica can be covered by the polymer, whereas remaining dispersed in aqueous solution. Under 980 nm laser excitation, UV light emitted by UCNP is absorbed by photolytic side groups within polyelectrolyte, which results in cleavage of o-nitrobenzyl groups and formation of carboxylic acid groups. Such NIR light-induced partial reversal of positive charge to negative charge on the polyelectrolyte layer disrupts the equilibrium among UCNP@silica, polyelectrolyte, and FLU and, consequently, leads to release of FLU molecules.

  14. Numerical modelling of needle-grid electrodes for negative surface corona charging system

    NASA Astrophysics Data System (ADS)

    Zhuang, Y.; Chen, G.; Rotaru, M.

    2011-08-01

    Surface potential decay measurement is a simple and low cost tool to examine electrical properties of insulation materials. During the corona charging stage, a needle-grid electrodes system is often used to achieve uniform charge distribution on the surface of the sample. In this paper, a model using COMSOL Multiphysics has been developed to simulate the gas discharge. A well-known hydrodynamic drift-diffusion model was used. The model consists of a set of continuity equations accounting for the movement, generation and loss of charge carriers (electrons, positive and negative ions) coupled with Poisson's equation to take into account the effect of space and surface charges on the electric field. Four models with the grid electrode in different positions and several mesh sizes are compared with a model that only has the needle electrode. The results for impulse current and surface charge density on the sample clearly show the effect of the extra grid electrode with various positions.

  15. Effect of surface charge density on the affinity of oxide nanoparticles for the vapor-water interface.

    PubMed

    Brown, Matthew A; Duyckaerts, Nicolas; Redondo, Amaia Beloqui; Jordan, Inga; Nolting, Frithjof; Kleibert, Armin; Ammann, Markus; Wörner, Hans Jakob; van Bokhoven, Jeroen A; Abbas, Zareen

    2013-04-23

    Using in-situ X-ray photoelectron spectroscopy at the vapor-water interface, the affinity of nanometer-sized silica colloids to adsorb at the interface is shown to depend on colloid surface charge density. In aqueous suspensions at pH 10 corrected Debye-Hückel theory for surface complexation calculations predict that smaller silica colloids have increased negative surface charge density that originates from enhanced screening of deprotonated silanol groups (≡Si-O(-)) by counterions in the condensed ion layer. The increased negative surface charge density results in an electrostatic repulsion from the vapor-water interface that is seen to a lesser extent for larger particles that have a reduced charge density in the XPS measurements. We compare the results and interpretation of the in-situ XPS and corrected Debye-Hückel theory for surface complexation calculations with traditional surface tension measurements. Our results show that controlling the surface charge density of colloid particles can regulate their adsorption to the interface between two dielectrics.

  16. Ordered adsorption of coagulation factor XII on negatively charged polymer surfaces probed by sum frequency generation vibrational spectroscopy.

    PubMed

    Chen, Xiaoyun; Wang, Jie; Paszti, Zoltan; Wang, Fulin; Schrauben, Joel N; Tarabara, Volodymyr V; Schmaier, Alvin H; Chen, Zhan

    2007-05-01

    Electrostatic interactions between negatively charged polymer surfaces and factor XII (FXII), a blood coagulation factor, were investigated by sum frequency generation (SFG) vibrational spectroscopy, supplemented by several analytical techniques including attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR), quartz crystal microbalance (QCM), zeta-potential measurement, and chromogenic assay. A series of sulfonated polystyrenes (sPS) with different sulfonation levels were synthesized as model surfaces with different surface charge densities. SFG spectra collected from FXII adsorbed onto PS and sPS surfaces with different surface charge densities showed remarkable differences in spectral features and especially in spectral intensity. Chromogenic assay experiments showed that highly charged sPS surfaces induced FXII autoactivation. ATR-FTIR and QCM results indicated that adsorption amounts on the PS and sPS surfaces were similar even though the surface charge densities were different. No significant conformational change was observed from FXII adsorbed onto surfaces studied. Using theoretical calculations, the possible contribution from the third-order nonlinear optical effect induced by the surface electric field was evaluated, and it was found to be unable to yield the SFG signal enhancement observed. Therefore it was concluded that the adsorbed FXII orientation and ordering were the main reasons for the remarkable SFG amide I signal increase on sPS surfaces. These investigations indicate that negatively charged surfaces facilitate or induce FXII autoactivation on the molecular level by imposing specific orientation and ordering on the adsorbed protein molecules.

  17. Interactions and diffusion in fine-stranded β-lactoglobulin gels determined via FRAP and binding.

    PubMed

    Schuster, Erich; Hermansson, Anne-Marie; Ohgren, Camilla; Rudemo, Mats; Lorén, Niklas

    2014-01-07

    The effects of electrostatic interactions and obstruction by the microstructure on probe diffusion were determined in positively charged hydrogels. Probe diffusion in fine-stranded gels and solutions of β-lactoglobulin at pH 3.5 was determined using fluorescence recovery after photobleaching (FRAP) and binding, which is widely used in biophysics. The microstructures of the β-lactoglobulin gels were characterized using transmission electron microscopy. The effects of probe size and charge (negatively charged Na2-fluorescein (376Da) and weakly anionic 70kDa FITC-dextran), probe concentration (50 to 200 ppm), and β-lactoglobulin concentration (9% to 12% w/w) on the diffusion properties and the electrostatic interaction between the negatively charged probes and the positively charged gels or solutions were evaluated. The results show that the diffusion of negatively charged Na2-fluorescein is strongly influenced by electrostatic interactions in the positively charged β-lactoglobulin systems. A linear relationship between the pseudo-on binding rate constant and the β-lactoglobulin concentration for three different probe concentrations was found. This validates an important assumption of existing biophysical FRAP and binding models, namely that the pseudo-on binding rate constant equals the product of the molecular binding rate constant and the concentration of the free binding sites. Indicators were established to clarify whether FRAP data should be analyzed using a binding-diffusion model or an obstruction-diffusion model. Copyright © 2014 Biophysical Society. Published by Elsevier Inc. All rights reserved.

  18. Correlation between octanol/water and liposome/water distribution coefficients and drug absorption of a set of pharmacologically active compounds.

    PubMed

    Esteves, Freddy; Moutinho, Carla; Matos, Carla

    2013-06-01

    Absorption and consequent therapeutic action are key issues in the development of new drugs by the pharmaceutical industry. In this sense, different models can be used to simulate biological membranes to predict the absorption of a drug. This work compared the octanol/water and the liposome/water models. The parameters used to relate the two models were the distribution coefficients between liposomes and water and octanol and water and the fraction of drug orally absorbed. For this study, 66 drugs were collected from literature sources and divided into four groups according to charge and ionization degree: neutral; positively charged; negatively charged; and partially ionized/zwitterionic. The results show a satisfactory linear correlation between the octanol and liposome systems for the neutral (R²= 0.9324) and partially ionized compounds (R²= 0.9367), contrary to the positive (R²= 0.4684) and negatively charged compounds (R²= 0.1487). In the case of neutral drugs, results were similar in both models because of the high fraction orally absorbed. However, for the charged drugs (positively, negatively, and partially ionized/zwitterionic), the liposomal model has a more-appropriate correlation with absorption than the octanol model. These results show that the neutral compounds only interact with membranes through hydrophobic bonds, whereas charged drugs favor electrostatic interactions established with the liposomes. With this work, we concluded that liposomes may be a more-appropriate biomembrane model than octanol for charged compounds.

  19. Nb and Ta layer doping effects on the interfacial energetics and electronic properties of LaAlO3/SrTiO3 heterostructure: first-principles analysis.

    PubMed

    Nazir, Safdar; Behtash, Maziar; Cheng, Jianli; Luo, Jian; Yang, Kesong

    2016-01-28

    The two-dimensional electron gas (2DEG) formed at the n-type (LaO)(+1)/(TiO2)(0) interface in the polar/nonpolar LaAlO3/SrTiO3 (LAO/STO) heterostructure (HS) has emerged as a prominent research area because of its great potential for nanoelectronic applications. Due to its practical implementation in devices, desired physical properties such as high charge carrier density and mobility are vital. In this respect, 4d and 5d transition metal doping near the interfacial region is expected to tailor electronic properties of the LAO/STO HS system effectively. Herein, we studied Nb and Ta-doping effects on the energetics, electronic structure, interfacial charge carrier density, magnetic moment, and the charge confinements of the 2DEG at the n-type (LaO)(+1)/(TiO2)(0) interface of LAO/STO HS using first-principles density functional theory calculations. We found that the substitutional doping of Nb(Ta) at Ti [Nb(Ta)@Ti] and Al [Nb(Ta)@Al] sites is energetically more favorable than that at La [Nb(Ta)@La] and Sr [Nb(Ta)@Sr] sites, and under appropriate thermodynamic conditions, the changes in the interfacial energy of HS systems upon Nb(Ta)@Ti and Nb(Ta)@Al doping are negative, implying that the formation of these structures is energetically favored. Our calculations also showed that Nb(Ta)@Ti and Nb(Ta)@Al doping significantly improve the interfacial charge carrier density with respect to that of the undoped system, which is because the Nb(Ta) dopant introduces excess free electrons into the system, and these free electrons reside mainly on the Nb(Ta) ions and interfacial Ti ions. Hence, along with the Ti 3d orbitals, the Nb 4d and Ta 5d orbitals also contribute to the interfacial metallic states; accordingly, the magnetic moments on the interfacial Ti ions increase significantly. As expected, the Nb@Al and Ta@Al doped LAO/STO HS systems show higher interfacial charge carrier density than the undoped and other doped systems. In contrast, Nb@Ti and Ta@Ti doped systems may show higher charge carrier mobility because of the lower electron effective mass.

  20. Effect of Temperature on the Physico-Chemical Properties of a Room Temperature Ionic Liquid (1-Methyl-3-pentylimidazolium Hexafluorophosphate) with Polyethylene Glycol Oligomer

    PubMed Central

    Wu, Tzi-Yi; Chen, Bor-Kuan; Hao, Lin; Peng, Yu-Chun; Sun, I-Wen

    2011-01-01

    A systematic study of the effect of composition on the thermo-physical properties of the binary mixtures of 1-methyl-3-pentyl imidazolium hexafluorophosphate [MPI][PF6] with poly(ethylene glycol) (PEG) [Mw = 400] is presented. The excess molar volume, refractive index deviation, viscosity deviation, and surface tension deviation values were calculated from these experimental density, ρ, refractive index, n, viscosity, η, and surface tension, γ, over the whole concentration range, respectively. The excess molar volumes are negative and continue to become increasingly negative with increasing temperature; whereas the viscosity and surface tension deviation are negative and become less negative with increasing temperature. The surface thermodynamic functions, such as surface entropy, enthalpy, as well as standard molar entropy, Parachor, and molar enthalpy of vaporization for pure ionic liquid, have been derived from the temperature dependence of the surface tension values. PMID:21731460

  1. Mechanics of dual-mode dilative failure in subaqueous sediment deposits

    NASA Astrophysics Data System (ADS)

    You, Yao; Flemings, Peter; Mohrig, David

    2014-07-01

    We introduce dual-mode dilative failure with flume experiments. Dual-mode dilative failure combines slow and steady release of sediments by breaching with periodic sliding, which rapidly releases an internally coherent wedge of sediments. It occurs in dilative sandy deposits. This periodic slope failure results from cyclic evolution of the excess pore pressure in the deposit. Sliding generates large, transient, negative excess pore pressure that strengthens the deposit and allows breaching to occur. During breaching, negative excess pore pressure dissipates, the deposit weakens, and ultimately sliding occurs once again. We show that the sliding frequency is proportional to the coefficient of consolidation. We find that thicker deposits are more susceptible to dual-mode dilative failure. Discovery of dual-mode dilative failure provides a new mechanism to consider when interpreting the sedimentary deposits linked to submarine slope failures.

  2. Carbon Dioxide Removal by Salty Aerosols

    NASA Astrophysics Data System (ADS)

    Gokturk, H.

    2016-12-01

    Aerosols consisting of salt ions dissolved in water are observed in nature as sea spray particles generated by breaking waves. Such aerosols can be also generated artificially by spraying seawater to the atmosphere to create clouds, which was suggested as a method of solar radiation management (SRM). Salty aerosols can be utilized not only for SRM, but also for carbon dioxide removal from the atmosphere, if salt ions carrying charges -2 or more negative are added to the seawater. CO2 is a very stable molecule where carbon to oxygen double bond has a bond strength of 8.3 eV (190 kcal/mol). Therefore the approach chosen here to modify CO2 is to further oxidize it to CO3. Quantum mechanical calculations indicate that CO2 reacts readily with hydroxyl minus ion (OH-) or oxygen double minus ion (O-) to form HCO3- or CO3-, respectively. What is studied in this paper is the utilization of hydrated negative salt ions to create OH- and possibly even O-. The negative ions chosen are chlorine minus ion (Cl-), sulfate double minus ion (SO4-), phosphate triple minus ion (PO4--) and silicate quadruple minus ion (SiO4--). The former two ions exist in seawater, but the latter two ions do not, though they are available as part of water soluble salts such as potassium phosphate. Using quantum mechanical calculations, following reactions were investigated: R1: (Cl-) + H2O => HCl + (OH-), R2: (SO4-) + H2O => (HSO4-) + (OH-), R3: (PO4--) + H2O => (HPO4-) + (OH-), R4: (SiO4--) + H2O => (HSiO4--) + (OH-), R5: (HPO4-) + H2O => (H2PO4-) + (OH-), R6: (HSiO4--) + H2O => (H2SiO4-) + (OH-), R7: (H2SiO4-) + H2O => (H3SiO4-) + (OH-), R8: (SiO4--) + H2O => (H2SiO4-) + (O-). Results indicate that singly charged negative salt ions, such as Cl- in R1, cannot create OH-. Doubly charged negative salt ions, such as SO4- in R2, can create OH-, though the amount of SO4- in seawater is relatively small. Triply or quadruply charged negative ions are even more favorable than doubly charged ions in creating OH- (R3, R4, R6). Quadruply charged negative ions can also create O- (R8), however in practice O- is likely to react with other water molecules to create more OH-. In conclusion, seawater fortified with highly charged negative salt ions and sprayed into the atmosphere has the potential to create aerosols containing OH- which can react with the CO2 and modify it to a carbonate.

  3. Effect of Primary-Ion Current Density on Charge Compensation in SIMS Analysis of a Quartz Glass

    NASA Astrophysics Data System (ADS)

    Inoue, Kazuyuki; Isogai, Akio

    1988-05-01

    In secondary ion mass spectrometry (SIMS) analysis of a quartz glass by means of negative ion bombardment, the effect of the negative ion current density (Ji) has been investigated. The results show that under lower Ji (<20 μA/cm2), time is required to compensate for the surface charge and the time is inversely proportional to Ji.

  4. Radiation transport codes for potential applications related to radiobiology and radiotherapy using protons, neutrons, and negatively charged pions

    NASA Technical Reports Server (NTRS)

    Armstrong, T. W.

    1972-01-01

    Several Monte Carlo radiation transport computer codes are used to predict quantities of interest in the fields of radiotherapy and radiobiology. The calculational methods are described and comparisions of calculated and experimental results are presented for dose distributions produced by protons, neutrons, and negatively charged pions. Comparisons of calculated and experimental cell survival probabilities are also presented.

  5. Double layer of platinum electrodes: Non-monotonic surface charging phenomena and negative double layer capacitance

    NASA Astrophysics Data System (ADS)

    Huang, Jun; Zhou, Tao; Zhang, Jianbo; Eikerling, Michael

    2018-01-01

    In this study, a refined double layer model of platinum electrodes accounting for chemisorbed oxygen species, oriented interfacial water molecules, and ion size effects in solution is presented. It results in a non-monotonic surface charging relation and a peculiar capacitance vs. potential curve with a maximum and possibly negative values in the potential regime of oxide-formation.

  6. Excessive sleepiness in adolescents and young adults: causes, consequences, and treatment strategies.

    PubMed

    Millman, Richard P

    2005-06-01

    Adolescents and young adults are often excessively sleepy. This excessive sleepiness can have a profound negative effect on school performance, cognitive function, and mood and has been associated with other serious consequences such as increased incidence of automobile crashes. In this article we review available scientific knowledge about normal sleep changes in adolescents (13-22 years of age), the factors associated with chronic insufficient sleep, the effect of insufficient sleep on a variety of systems and functions, and the primary sleep disorders or organic dysfunctions that, if untreated, can cause excessive daytime sleepiness in this population.

  7. Stick slip, charge separation and decay

    USGS Publications Warehouse

    Lockner, D.A.; Byerlee, J.D.; Kuksenko, V.S.; Ponomarev, A.V.

    1986-01-01

    Measurements of charge separation in rock during stable and unstable deformation give unexpectedly large decay times of 50 sec. Time-domain induced polarization experiments on wet and dry rocks give similar decay times and suggest that the same decay mechanisms operate in the induced polarization response as in the relaxation of charge generated by mechanical deformation. These large decay times are attributed to electrochemical processes in the rocks, and they require low-frequency relative permittivity to be very large, in excess of 105. One consequence of large permittivity, and therefore long decay times, is that a significant portion of any electrical charge generated during an earthquake can persist for tens or hundreds of seconds. As a result, electrical disturbances associated with earthquakes should be observable for these lengths of time rather than for the milliseconds previously suggested. ?? 1986 Birka??user Verlag.

  8. Relating Silica Scaling in Reverse Osmosis to Membrane Surface Properties.

    PubMed

    Tong, Tiezheng; Zhao, Song; Boo, Chanhee; Hashmi, Sara M; Elimelech, Menachem

    2017-04-18

    We investigated the relationship between membrane surface properties and silica scaling in reverse osmosis (RO). The effects of membrane hydrophilicity, free energy for heterogeneous nucleation, and surface charge on silica scaling were examined by comparing thin-film composite polyamide membranes grafted with a variety of polymers. Results show that the rate of silica scaling was independent of both membrane hydrophilicity and free energy for heterogeneous nucleation. In contrast, membrane surface charge demonstrated a strong correlation with the extent of silica scaling (R 2 > 0.95, p < 0.001). Positively charged membranes significantly facilitated silica scaling, whereas a more negative membrane surface charge led to reduced scaling. This observation suggests that deposition of negatively charged silica species on the membrane surface plays a critical role in silica scale formation. Our findings provide fundamental insights into the mechanisms governing silica scaling in reverse osmosis and highlight the potential of membrane surface modification as a strategy to reduce silica scaling.

  9. The impact of prescription charges on asthma patients is uneven and unpredictable: evidence from qualitative interviews.

    PubMed

    Schafheutle, Ellen I

    2009-12-01

    To explore whether, and how, prescription charges affect asthma patients' disease management behaviour. Thirty qualitative interviews. Interviewees were aged between 21 and 59, 21 were women, 24 were paying individual prescription charges, and six had prepayment certificates (PPCs). Most had a beta2-agonist 'reliever' and a steroid 'preventer' inhaler. Prescription charges posed affordability issues for some, and for two patients cost-related reduction in 'preventer' use affected asthma control negatively. Many described various ways of keeping medication cost down. Affordability issues, negative views on paying charges, and whether interviewees viewed their asthma medication as essential, were influential factors. Steroid inhalers were viewed more commonly as being less essential and affected by cost. The episodic nature of asthma meant that predicting benefit from PPCs was difficult. This study strengthens existing evidence that medication cost is a factor in asthma patients' management decisions, with a potential cost-related impact on asthma control.

  10. Excessive Internet gaming and decision making: do excessive World of Warcraft players have problems in decision making under risky conditions?

    PubMed

    Pawlikowski, Mirko; Brand, Matthias

    2011-08-15

    The dysfunctional behavior of excessive Internet gamers, such as preferring the immediate reward (to play World of Warcraft) despite the negative long-term consequences may be comparable with the dysfunctional behavior in substance abusers or individuals with behavioral addictions, e.g. pathological gambling. In these disorders, general decision-making deficits have been demonstrated. Hence, the aim of the present work was to examine decision-making competences of excessive World of Warcraft players. Nineteen excessive Internet gamers (EIG) and a control group (CG) consisting of 19 non-gamers were compared with respect to decision-making abilities. The Game of Dice Task (GDT) was applied to measure decision-making under risky conditions. Furthermore psychological-psychiatric symptoms were assessed in both groups. The EIG showed a reduced decision-making ability in the GDT. Furthermore the EIG group showed a higher psychological-psychiatric symptomatology in contrast to the CG. The results indicate that the reduced decision-making ability of EIG is comparable with patients with other forms of behavioral addiction (e.g. pathological gambling), impulse control disorders or substance abusers. Thus, these results suggest that excessive Internet gaming may be based on a myopia for the future, meaning that EIG prefer to play World of Warcraft despite the negative long-term consequences in social or work domains of life. 2011 Elsevier Ltd. All rights reserved.

  11. Plasma bullet current measurements in a free-stream helium capillary jet

    NASA Astrophysics Data System (ADS)

    Oh, Jun-Seok; Walsh, James L.; Bradley, James W.

    2012-06-01

    A commercial current monitor has been used to measure the current associated with plasma bullets created in both the positive and negative half cycles of the sinusoidal driving voltage sustaining a plasma jet. The maximum values of the positive bullet current are typically ˜750 µA and persist for 10 µs, while the peaks in the negative current of several hundred μA are broad, persisting for about 40 µs. From the time delay of the current peaks with increasing distance from the jet nozzle, an average bullet propagation speed has been measured; the positive and negative bullets travel at 17.5 km s-1 and 3.9 km s-1 respectively. The net space charge associated with the bullet(s) has also been calculated; the positive and negative bullets contain a similar net charge of the order of 10-9 C measured at all monitor positions, with estimated charged particle densities nb of ˜1010-1011 cm-3 in the bullet.

  12. 12 CFR 5.20 - Organizing a bank.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... the following three core banking functions: receiving deposits; paying checks; or lending money. The.... Organizers should not bill excessive charges to the bank for professional and consulting services or unduly..., nonprofit, and government sectors. The business plan or operating plan must demonstrate how the proposed...

  13. 7 CFR 29.127 - Demonstrations and courses of instruction.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... Section 29.127 Agriculture Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing Practices), DEPARTMENT OF AGRICULTURE COMMODITY STANDARDS AND STANDARD... instruction. Charges, not in excess of the cost thereof, as may be approved by the Director, may be made for...

  14. 7 CFR 97.178 - Refunds.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... VARIETY AND PROTECTION Fees and Charges § 97.178 Refunds. Money paid by mistake or excess payments shall be refunded, but a mere change of plans after the payment of money, as when a party decides to... of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Standards, Inspections...

  15. 7 CFR 2812.7 - Costs.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 15 2010-01-01 2010-01-01 false Costs. 2812.7 Section 2812.7 Agriculture Regulations of the Department of Agriculture (Continued) OFFICE OF OPERATIONS, DEPARTMENT OF AGRICULTURE...) § 2812.7 Costs. Donated excess personal property/equipment is free of charge. However, the donee must pay...

  16. Emotionally laden impulsivity interacts with affect in predicting addictive use of online sexual activity in men.

    PubMed

    Wéry, Aline; Deleuze, Jory; Canale, Natale; Billieux, Joël

    2018-01-01

    The interest in studying addictive use of online sexual activities (OSA) has grown sharply over the last decade. Despite the burgeoning number of studies conceptualizing the excessive use of OSA as an addictive disorder, few have tested its relations to impulsivity, which is known to constitute a hallmark of addictive behaviors. To address this missing gap in the literature, we tested the relationships between addictive OSA use, impulsivity traits, and affect among a convenience sample of men (N=182; age, M=29.17, SD = 9.34), building upon a theoretically driven model that distinguishes the various facets of impulsivity. Results showed that negative urgency (an impulsivity trait reflecting the tendency to act rashly in negative emotional states) and negative affect interact in predicting addictive OSA use. These results highlight the pivotal role played by negative urgency and negative affect in addictive OSA use, supporting the relevance of psychological interventions that focus on improving emotional regulation (e.g., to reduce negative affect and learn healthier coping strategies) to mitigate excessive use of OSA. Copyright © 2017 Elsevier Inc. All rights reserved.

  17. Effect of cholesterol on electrostatics in lipid-protein films of a pulmonary surfactant.

    PubMed

    Finot, Eric; Leonenko, Yuri; Moores, Brad; Eng, Lukas; Amrein, Matthias; Leonenko, Zoya

    2010-02-02

    We report the changes in the electrical properties of the lipid-protein film of pulmonary surfactant produced by excess cholesterol. Pulmonary surfactant (PS) is a complex lipid-protein mixture that forms a molecular film at the interface of the lung's epithelia. The defined molecular arrangement of the lipids and proteins of the surfactant film gives rise to the locally highly variable electrical surface potential of the interface, which becomes considerably altered in the presence of cholesterol. With frequency modulation Kelvin probe force microscopy (FM-KPFM) and force measurements, complemented by theoretical analysis, we showed that excess cholesterol significantly changes the electric field around a PS film because of the presence of nanometer-sized electrostatic domains and affects the electrostatic interaction of an AFM probe with a PS film. These changes in the local electrical field would greatly alter the interaction of the surfactant film with charged species and would immediately impact the manner in which inhaled (often charged) airborne nanoparticles and fibers might interact with the lung interface.

  18. Profiling of Current Transients in Capacitor Type Diamond Sensors

    PubMed Central

    Gaubas, Eugenijus; Ceponis, Tomas; Meskauskaite, Dovile; Kazuchits, Nikolai

    2015-01-01

    The operational characteristics of capacitor-type detectors based on HPHT and CVD diamond have been investigated using perpendicular and parallel injection of carrier domain regimes. Simulations of the drift-diffusion current transients have been implemented by using dynamic models based on Shockley-Ramo’s theorem, under injection of localized surface domains and of bulk charge carriers. The bipolar drift-diffusion regimes have been analyzed for the photo-induced bulk domain (packet) of excess carriers. The surface charge formation and polarization effects dependent on detector biasing voltage have been revealed. The screening effects ascribed to surface charge and to dynamics of extraction of the injected bulk excess carrier domain have been separated and explained. The parameters of drift mobility of the electrons μe = 4000 cm2/Vs and holes μh = 3800 cm2/Vs have been evaluated for CVD diamond using the perpendicular profiling of currents. The coefficient of carrier ambipolar diffusion Da = 97 cm2/s and the carrier recombination lifetime τR,CVD ≌ 110 ns in CVD diamond were extracted by combining analysis of the transients of the sensor current and the microwave probed photoconductivity. The carrier trapping with inherent lifetime τR,HPHT ≌ 2 ns prevails in HPHT diamond. PMID:26061200

  19. Dark Coulomb binding of heavy neutrinos of fourth family

    NASA Astrophysics Data System (ADS)

    Belotsky, K. M.; Esipova, E. A.; Khlopov, M. Yu.; Laletin, M. N.

    2015-11-01

    Direct dark matter searches put severe constraints on the weakly interacting massive particles (WIMPs). These constraints cause serious troubles for the model of stable neutrino of fourth generation with mass around 50GeV. Though the calculations of primordial abundance of these particles make them in the charge symmetric case a sparse subdominant component of the modern dark matter, their presence in the universe would exceed the current upper limits by several orders of the magnitude. However, if quarks and leptons of fourth generation possess their own Coulomb-like y-interaction, recombination of pairs of heavy neutrinos and antineutrinos and their annihilation in the “neutrinium” atoms can play important role in their cosmological evolution, reducing their modern abundance far below the experimental upper limits. The model of stable fourth generation assumes that the dominant part of dark matter is explained by excessive Ū antiquarks, forming (ŪŪŪ)-- charged clusters, bound with primordial helium in nuclear-interacting O-helium (OHe) dark atoms. The y charge conservation implies generation of the same excess of fourth generation neutrinos, potentially dangerous WIMP component of this scenario. We show that due to y-interaction recombination of fourth neutrinos with OHe hides these WIMPs from direct WIMP searches, leaving the negligible fraction of free neutrinos, what makes their existence compatible with the experimental constraints.

  20. Super-reduced polyoxometalates: excellent molecular cluster battery components and semipermeable molecular capacitors.

    PubMed

    Nishimoto, Yoshio; Yokogawa, Daisuke; Yoshikawa, Hirofumi; Awaga, Kunio; Irle, Stephan

    2014-06-25

    Theoretical investigations are presented on the molecular and electronic structure changes that occur as α-Keggin-type polyoxometalate (POM(3-)) clusters [PM12O40](3-) (M = Mo, W) are converted toward their super-reduced POM(27-) state during the discharging process in lithium-based molecular cluster batteries. Density functional theory was employed in geometry optimization, and first-principles molecular dynamics simulations were used to explore local minima on the potential energy surface of neutral POM clusters adorned with randomly placed Li atoms as electron donors around the cluster surface. On the basis of structural, electron density, and molecular orbital studies, we present evidence that the super-reduction is accompanied by metal-metal bond formation, beginning from the 12th to 14th excess electron transferred to the cluster. Afterward, the number of metal-metal bonds increases nearly linearly with the number of additionally transferred excess electrons. In α-Keggin-type POMs, metal triangles are a prominently emerging structural feature. The origin of the metal triangle formation during super-reduction stems from the formation of characteristic three-center two-electron bonds in triangular metal atom sites, created under preservation of the POM skeleton via "squeezing out" of oxygen atoms bridging two metal atoms when the underlying metal atoms form covalent bonds. The driving force for this unusual geometrical and electronic structure change is a local Jahn-Teller distortion at individual transition-metal octahedral sites, where the triply degenerate t2 d orbitals become partially filled during reduction and gain energy by distortion of the octahedron in such a way that metal-metal bonds are formed. The bonding orbitals show strong contributions from mixing with metal-oxygen antibonding orbitals, thereby "shuffling away" excess electrons from the cluster center to the outside of the cage. The high density of negatively charged yet largely separated oxygen atoms on the surface of the super-reduced POM(27-) polyanion allows the huge Coulombic repulsion due to the presence of the excess electrons to be counterbalanced by the presence of Li countercations, which partially penetrate into the outer oxygen shell. This "semiporous molecular capacitor" structure is likely the reason for the effective electron uptake in POMs.

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