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Sample records for asymmetric salt ion

  1. Intrinsic potential of cell membranes: opposite effects of lipid transmembrane asymmetry and asymmetric salt ion distribution

    DEFF Research Database (Denmark)

    Gurtovenko, Andrey A; Vattulainen, Ilpo

    2009-01-01

    Using atomic-scale molecular dynamics simulations, we consider the intrinsic cell membrane potential that is found to originate from a subtle interplay between lipid transmembrane asymmetry and the asymmetric distribution of monovalent salt ions on the two sides of the cell membrane. It turns out......Cl saline solution and the PE leaflet is exposed to KCl, the outcome is that the effects of asymmetric lipid and salt ion distributions essentially cancel one another almost completely. Overall, our study highlights the complex nature of the intrinsic potential of cell membranes under physiological...

  2. Salt supply to and significance of asymmetric salt diapirs

    DEFF Research Database (Denmark)

    Koyi, H.; Burliga, S.; Chemia, Zurab

    2012-01-01

    Salt diapirs can be asymmetric both internally and externally reflecting their evolution history. As such, this asymmetry bear a significant amount of information about the differential loading (± lateral forces) and in turn the salt supply that have shaped the diapir. In two dimensions......, In this study we compare results of analogue and numerical models of diapirs with two natural salt diapris (Klodawa and Gorleben diapirs) to explain their salt supply and asymmetric evolution. In a NW-SE section, the Gorleben salt diapir possesses an asymmetric external geometry represented by a large...... southeastern overhang due to salt extrusion during Middle Cretaceous followed by its burial in Tertiary. This external asymmetry is also reflected in the internal configuration of the diapir which shows different rates of salt flow on the two halves of the structure. The asymmetric external and internal...

  3. Asymmetric Hydrogenation of 3-Substituted Pyridinium Salts

    NARCIS (Netherlands)

    Renom-Carrasco, Marc; Gajewski, Piotr; Pignataro, Luca; de Vries, Johannes G.; Piarulli, Umberto; Gennari, Cesare; Lefort, Laurent

    2016-01-01

    The use of an equivalent amount of an organic base leads to high enantiomeric excess in the asymmetric hydrogenation of N-benzylated 3-substituted pyridinium salts into the corresponding piperidines. Indeed, in the presence of Et3N, a Rh-JosiPhos catalyst reduced a range of pyridinium salts with ee

  4. Direction- and Salt-Dependent Ionic Current Signatures for DNA Sensing with Asymmetric Nanopores.

    Science.gov (United States)

    Chen, Kaikai; Bell, Nicholas A W; Kong, Jinglin; Tian, Yu; Keyser, Ulrich F

    2017-02-28

    Solid-state nanopores are promising tools for single-molecule detection of both DNA and proteins. In this study, we investigated the patterns of ionic current blockades as DNA translocates into or out of the geometric confinement of conically shaped pores across a wide range of salt conditions. We studied how the geometry of a nanopore affects the detected ionic current signal of a translocating DNA molecule over a wide range of salt concentration. The blockade level in the ionic current depends on the translocation direction at a high salt concentration, and at lower salt concentrations we find a nonintuitive ionic current decrease and increase within each single event for the DNA translocations exiting from confinement. We use a recently developed method for synthesizing DNA molecules with multiple position markers, which provides further experimental characterization by matching the position of the DNA in the pore with the observed ionic current signal. Finally, we employ finite element calculations to explain the shapes of the signals observed at all salt concentrations and show that the unexpected current decrease and increase are due to the competing effects of ion concentration polarization and geometric exclusion of ions. Our analysis shows that over a wide range of geometries, voltages, and salt concentrations, we are able to understand the ionic current signals of DNA in asymmetric nanopores, enabling signal optimization in molecular sensing applications.

  5. Multicomponent asymmetric reactions mediated by proline lithium salt

    DEFF Research Database (Denmark)

    Renzi, Polyssena; Overgaard, Jacob; Bella, Marco

    2010-01-01

    The multicomponent reaction between proline lithium salt, 2-cyclohexen-1-one and aliphatic aldehydes affords the 4- alkylidene-2-cyclohexen-1-ones, which are interesting fragrances, and bicyclic amino acids that bear four additional stereocenters, obtained as single stereoisomer....

  6. Ion aggregation in high salt solutions. III. Computational vibrational spectroscopy of HDO in aqueous salt solutions

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Jun-Ho; Lim, Sohee; Chon, Bonghwan; Cho, Minhaeng, E-mail: mcho@korea.ac.kr [Center for Molecular Spectroscopy and Dynamics, Institute for Basic Science, Seoul 136-713 (Korea, Republic of); Department of Chemistry, Korea University, Seoul 136-713 (Korea, Republic of); Kim, Heejae; Kim, Seongheun [Department of Chemistry, Korea University, Seoul 136-713 (Korea, Republic of)

    2015-05-28

    The vibrational frequency, frequency fluctuation dynamics, and transition dipole moment of the O—D stretch mode of HDO molecule in aqueous solutions are strongly dependent on its local electrostatic environment and hydrogen-bond network structure. Therefore, the time-resolved vibrational spectroscopy the O—D stretch mode has been particularly used to investigate specific ion effects on water structure. Despite prolonged efforts to understand the interplay of O—D vibrational dynamics with local water hydrogen-bond network and ion aggregate structures in high salt solutions, still there exists a gap between theory and experiment due to a lack of quantitative model for accurately describing O—D stretch frequency in high salt solutions. To fill this gap, we have performed numerical simulations of Raman scattering and IR absorption spectra of the O—D stretch mode of HDO in highly concentrated NaCl and KSCN solutions and compared them with experimental results. Carrying out extensive quantum chemistry calculations on not only water clusters but also ion-water clusters, we first developed a distributed vibrational solvatochromic charge model for the O—D stretch mode in aqueous salt solutions. Furthermore, the non-Condon effect on the vibrational transition dipole moment of the O—D stretch mode was fully taken into consideration with the charge response kernel that is non-local polarizability density. From the fluctuating O—D stretch mode frequencies and transition dipole vectors obtained from the molecular dynamics simulations, the O—D stretch Raman scattering and IR absorption spectra of HDO in salt solutions could be calculated. The polarization effect on the transition dipole vector of the O—D stretch mode is shown to be important and the asymmetric line shapes of the O—D stretch Raman scattering and IR absorption spectra of HDO especially in highly concentrated NaCl and KSCN solutions are in quantitative agreement with experimental results. We

  7. Micro/nanofluidic Diode using Asymmetric Ion Concentration Polarization Layer

    Science.gov (United States)

    Sohn, Seoyun; Cho, Inhee; Kim, Sung Jae

    2016-11-01

    Recent developments of ion concentration polarization (ICP) theory would suggest that an over-limiting conductance (OLC) of the device is subject to the morphology of ICP layer and a micro-structure is able to alter the morphology. In this study, we demonstrated an ion rectification resulted only from asymmetric microscale structures, while conventional nanofluidic diode applications have usually employed a nanoscale asymmetry which requires sophisticate and expensive fabrication processes. We designed two dead-end microchannels incorporated with the nanoporous membrane. The difference in width of the microchannels was designed to yield asymmetry to the device. Cyclic voltammetry measurement was conducted to investigate the OLC behaviors on both forward and reverse bias. The diodic characteristics on I-V responses were observed at various ratio of the different microchannel width. In addition, we experimentally verified the logarithmical linearity between the ratios and the rectification ratios of OLC. This quantitative analysis would guide the further application utilizing microscale asymmetric diode device that now can be realized with minimum fabrication endeavors.

  8. Vinylimidazole-Based Asymmetric Ion Pair Comonomers: Synthesis, Polymerization Studies and Formation of Ionically Crosslinked PMMA

    NARCIS (Netherlands)

    Jana, S.; Vasantha, V.A.; Stubbs, L.P.; Parthiban, A.; Vancso, G.J.

    2013-01-01

    Vinylimidazole-based asymmetric ion pair comonomers (IPCs) which are free from nonpolymerizable counter ions have been synthesized, characterized and polymerized by free radical polymerization (FRP), atom transfer radical polymerization (ATRP), and reversible addition-fragmentation chain transfer (R

  9. Asymmetric ion transport through ion-channel-mimetic solid-state nanopores.

    Science.gov (United States)

    Guo, Wei; Tian, Ye; Jiang, Lei

    2013-12-17

    Both scientists and engineers are interested in the design and fabrication of synthetic nanofluidic architectures that mimic the gating functions of biological ion channels. The effort to build such structures requires interdisciplinary efforts at the intersection of chemistry, materials science, and nanotechnology. Biological ion channels and synthetic nanofluidic devices have some structural and chemical similarities, and therefore, they share some common features in regulating the traverse ionic flow. In the past decade, researchers have identified two asymmetric ion transport phenomena in synthetic nanofluidic structures, the rectified ionic current and the net diffusion current. The rectified ionic current is a diode-like current-voltage response that occurs when switching the voltage bias. This phenomenon indicates a preferential direction of transport in the nanofluidic system. The net diffusion current occurs as a direct product of charge selectivity and is generated from the asymmetric diffusion through charged nanofluidic channels. These new ion transport phenomena and the elaborate structures that occur in biology have inspired us to build functional nanofluidic devices for both fundamental research and practical applications. In this Account, we review our recent progress in the design and fabrication of biomimetic solid-state nanofluidic devices with asymmetric ion transport behavior. We demonstrate the origin of the rectified ionic current and the net diffusion current. We also identify several influential factors and discuss how to build these asymmetric features into nanofluidic systems by controlling (1) nanopore geometry, (2) surface charge distribution, (3) chemical composition, (4) channel wall wettability, (5) environmental pH, (6) electrolyte concentration gradient, and (7) ion mobility. In the case of the first four features, we build these asymmetric features directly into the nanofluidic structures. With the final three, we construct

  10. Influence of salt ions on binding to molecularly imprinted polymers.

    OpenAIRE

    Kempe, Henrik; Kempe, Maria

    2010-01-01

    Salt ions were found to have an influence on template binding to two model molecularly imprinted polymers (MIPs), targeted to penicillin G and propranolol, respectively, in water-acetonitrile mixtures. Water was detrimental to rebinding of penicillin G whereas propranolol bound in the entire water-acetonitrile range tested. In 100% aqueous solution, 3-M salt solutions augmented the binding of both templates. The effects followed the Hofmeister series with kosmotropic ions promoting the larges...

  11. Field Asymmetric Waveform Ion Mobility Spectrometry Studies of Proteins: Dipole Alignment in Ion Mobility Spectrometry?

    Energy Technology Data Exchange (ETDEWEB)

    Shvartsburg, Alexandre A.; Bryskiewicz, Tadeusz; Purves, Randy; Tang, Keqi; Guevremont, Roger; Smith, Richard D.

    2006-11-02

    Approaches to characterization and separation of ions involving their mobilities in gases were developed since 1960-s. Conventional ion mobility spectrometry (IMS) measures the absolute mobility and the field asymmetric waveform IMS (FAIMS) exploits the difference between mobilities at high and low electric fields. However, all previous work was based on the orientationally averaged cross-sections Ωavg between ions and buffer gas molecules. Virtually all large ions are electric dipoles that will be oriented by a sufficiently strong electric field. At typical FAIMS conditions, that must happen for dipole moments > ~400 Debye, found for many macroions including most proteins above ~30 kDa. Mobilities of aligned dipoles depend on directional cross-sections Ωdir (rather than Ωavg), which should have a major effect on FAIMS separation parameters. Here we study the FAIMS behavior of ESI-generated ions for ten proteins up to ~70 kDa. Those above 29 kDa exhibit a strong increase of mobility at high field, which is consistent with predicted ion dipole alignment. This effect expands the FAIMS peak capacity by an order of magnitude, allowing separation of up to ~102 distinct protein conformers and revealing information about Ωdir and ion dipole moment that is of potential utility for structural characterization. Possible means to extend the dipole alignment to smaller ions are discussed.

  12. Isotope separation using high-field asymmetric waveform ion mobility spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Barnett, David A.; Purves, Randy W.; Guevremont, Roger E-mail: roger.guevremont@nrc.ca

    2000-08-01

    A new apparatus for gas-phase separation of stable elemental isotopes at atmospheric pressure is described. A gaseous mixture of chloride isotopes was generated using electrospray ionization and introduced into the analyzer region of a high-field asymmetric waveform ion mobility spectrometer (FAIMS). The ion current exiting the FAIMS was sampled into a quadrupole mass spectrometer for isotope identification.

  13. Asymmetric ion track nanopores for sensor technology. Reconstruction of pore profile from conductometric measurements

    Science.gov (United States)

    Apel, Pavel Yu; Blonskaya, Irina V.; Orelovitch, Oleg L.; Sartowska, Bozena A.; Spohr, Reimar

    2012-06-01

    We reconstruct the profile of asymmetric ion track nanopores from an algorithm developed for conductometric measurements of symmetric nanopores. The validity of the reconstruction is supported by FESEM observations. Our analysis reveals that asymmetric pores fabricated by one-sided etching are funnel-like and not conical. The analysis provides the constriction diameter and the pore profile as a function of etching time. The reconstruction of the pore profile defines the starting conditions of asymmetric nanopores at breakthrough. The deviation from the conical shape is most pronounced at the pore tip. This critical zone dominates transport properties relevant to ion conductance, selectivity, current rectification, resistive pulse sensing and biosensors. The classical cone approximation used until now underestimates the tip diameter by a factor of two. As transport processes in nanopores depend in a highly nonlinear way on the constriction diameter the presented reconstruction must be taken into account when studying ionic and molecular transport processes in asymmetric pores.

  14. Influence of salt ions on binding to molecularly imprinted polymers.

    Science.gov (United States)

    Kempe, Henrik; Kempe, Maria

    2010-02-01

    Salt ions were found to have an influence on template binding to two model molecularly imprinted polymers (MIPs), targeted to penicillin G and propranolol, respectively, in water-acetonitrile mixtures. Water was detrimental to rebinding of penicillin G whereas propranolol bound in the entire water-acetonitrile range tested. In 100% aqueous solution, 3-M salt solutions augmented the binding of both templates. The effects followed the Hofmeister series with kosmotropic ions promoting the largest increase. Binding was mainly of a non-specific nature under these conditions. In acetonitrile containing low amounts of water, the specific binding to the MIPs increased with the addition of salts. Binding of penicillin G followed the Hofmeister series while an ion-exchange mechanism was observed for propranolol. The results suggest that hydration of kosmotropic ions reduces the water activity in water-poor media providing a stabilizing effect on water-sensitive MIP-template interactions. The effects were utilized to develop a procedure for molecularly imprinted solid-phase extraction (MISPE) of penicillin G from milk with a recovery of 87%.

  15. Ion yields for some salts in MALDI: mechanism for the gas-phase ion formation from preformed ions.

    Science.gov (United States)

    Moon, Jeong Hee; Shin, Young Sik; Bae, Yong Jin; Kim, Myung Soo

    2012-01-01

    Preformed ion emission is the main assumption in one of the prevailing theories for peptide and protein ion formation in matrix-assisted laser desorption ionization (MALDI). Since salts are in preformed ion forms in the matrix-analyte mixture, they are ideal systems to study the characteristics of preformed ion emission. In this work, a reliable method to measure the ion yield (IY) in MALDI was developed and used for a solid salt benzyltriphenylphosphonium chloride and two room-temperature ionic liquids 1-butyl-3-methylimidazolium hexafluorophosphate and trihexyltetradecylphosphonium bis(2,4,4-trimethylpentyl)phosphinate. IY for the matrix (α-cyano-4-hydroxycinnamic acid, CHCA) was also measured. Taking 1 pmol salts in 25 nmol CHCA as examples, IYs for three salts were similar, (4-8) × 10(-4), and those for CHCA were (0.8-1.2) × 10(-7). Even though IYs for the salts and CHCA remained virtually constant at low analyte concentration, they decreased as the salt concentrations increased. Two models, Model 1 and Model 2, were proposed to explain low IYs for the salts and the concentration dependences. Both models are based on the fact that the ion-pair formation equilibrium is highly shifted toward the neutral ion pair. In Model 1, the gas-phase analyte cations were proposed to originate from the same cations in the solid that were dielectrically screened from counter anions by matrix neutrals. In Model 2, preformed ions were assumed to be released from the solid sample in the form of neutral ion pairs and the anions in the ion pairs were assumed to be eliminated via reactions with matrix-derived cations.

  16. Electrodialysis-ion exchange for the separation of dissolved salts

    Energy Technology Data Exchange (ETDEWEB)

    Baroch, C.J. [Wastren, Inc., Westminster, CO (United States); Grant, P.J. [Wastren, Inc., Hummelstown, PA (United States)

    1995-10-01

    The Department of Energy generates and stores a significant quantity of low level, high level, and mixed wastes. As some of the DOE facilities are decontaminated and decommissioned, additional and possibly different forms of wastes will be generated. A significant portion of these wastes are aqueous streams containing acids, bases, and salts, or are wet solids containing inorganic salts. Some of these wastes are quite dilute solutions, whereas others contain large quantities of nitrates either in the form of dissolved salts or acids. Many of the wastes are also contaminated with heavy metals, radioactive products, or organics. Some of these wastes are in storage because a satisfactory treatment and disposal processes have not been developed. There is considerable interest in developing processes that remove or destroy the nitrate wastes. Electrodialysis-Ion Exchange (EDIX) is a possible process that should be more cost effective in treating aqueous waste steams. This report describes the EDIX process.

  17. Shielding factors of ions in rock-salt crystals

    Science.gov (United States)

    Michihiro, Y.; Mahan, G. D.

    1997-11-01

    The calculation of the quadrupole shielding factor of closed-shell ions in crystalline solids with rock-salt structure is done based on the self-consistent-field local-density approximation, modified Sternheimer equation, and spherical solid model. A significant reduction of the values of the quadrupole shielding factor is found for the anions, and the amount of the reduction is different in different crystals.

  18. Enhanced Salt Removal by Unipolar Ion Conduction in Ion Concentration Polarization Desalination

    Science.gov (United States)

    Kwak, Rhokyun; Pham, Van Sang; Kim, Bumjoo; Chen, Lan; Han, Jongyoon

    2016-05-01

    Chloride ion, the majority salt in nature, is ˜52% faster than sodium ion (DNa+ = 1.33, DCl- = 2.03[10-9m2s-1]). Yet, current electrochemical desalination technologies (e.g. electrodialysis) rely on bipolar ion conduction, removing one pair of the cation and the anion simultaneously. Here, we demonstrate that novel ion concentration polarization desalination can enhance salt removal under a given current by implementing unipolar ion conduction: conducting only cations (or anions) with the unipolar ion exchange membrane stack. Combining theoretical analysis, experiment, and numerical modeling, we elucidate that this enhanced salt removal can shift current utilization (ratio between desalted ions and ions conducted through electrodes) and corresponding energy efficiency by the factor ˜(D- - D+)/(D- + D+). Specifically for desalting NaCl, this enhancement of unipolar cation conduction saves power consumption by ˜50% in overlimiting regime, compared with conventional electrodialysis. Recognizing and utilizing differences between unipolar and bipolar ion conductions have significant implications not only on electromembrane desalination, but also energy harvesting applications (e.g. reverse electrodialysis).

  19. Enhanced Salt Removal by Unipolar Ion Conduction in Ion Concentration Polarization Desalination.

    Science.gov (United States)

    Kwak, Rhokyun; Pham, Van Sang; Kim, Bumjoo; Chen, Lan; Han, Jongyoon

    2016-05-09

    Chloride ion, the majority salt in nature, is ∼52% faster than sodium ion (DNa+ = 1.33, DCl- = 2.03[10(-9)m(2)s(-1)]). Yet, current electrochemical desalination technologies (e.g. electrodialysis) rely on bipolar ion conduction, removing one pair of the cation and the anion simultaneously. Here, we demonstrate that novel ion concentration polarization desalination can enhance salt removal under a given current by implementing unipolar ion conduction: conducting only cations (or anions) with the unipolar ion exchange membrane stack. Combining theoretical analysis, experiment, and numerical modeling, we elucidate that this enhanced salt removal can shift current utilization (ratio between desalted ions and ions conducted through electrodes) and corresponding energy efficiency by the factor ∼(D- - D+)/(D- + D+). Specifically for desalting NaCl, this enhancement of unipolar cation conduction saves power consumption by ∼50% in overlimiting regime, compared with conventional electrodialysis. Recognizing and utilizing differences between unipolar and bipolar ion conductions have significant implications not only on electromembrane desalination, but also energy harvesting applications (e.g. reverse electrodialysis).

  20. Ion aggregation in high salt solutions. VI. Spectral graph analysis of chaotropic ion aggregates

    Science.gov (United States)

    Choi, Jun-Ho; Cho, Minhaeng

    2016-11-01

    Carrying out molecular dynamics simulations and graph theoretical analyses of high salt solutions, and comparing numerically calculated vibrational spectroscopic properties of water with femtosecond IR pump-probe experimental data, we have recently found that ions in high salt solutions can form two morphologically different ion aggregate structures. In the cases of NaCl solutions, Na+ and Cl- tend to form compact cluster-like ion aggregate in high NaCl solutions. In contrast, K+ and SCN- form spatially extended network-like ion aggregates that also exhibit a percolating network behavior. Interestingly, a variety of graph theoretical properties of ion network in high KSCN solutions were found to be very similar to those of water H-bonding network. It was shown that spatially extended ion networks in high KSCN solutions are completely intertwined with water H-bonding networks, which might be the key to understand the high solubility of thiocyanate salts in water. Here, we further consider two salts that have been extensively studied experimentally by using femtosecond IR pump-probe technique, which are NaClO4 and NaBF4. Note that ClO4 - and BF4 - are well-known chaotropic ions that have been believed to behave as water structure breaker. To understand how such chaotropic ions affect water H-bonding structure, we carried out spectral graph analyses of molecular dynamics simulation data of these aqueous solutions. Graph spectra and degree distribution of ion aggregates formed in high NaBF4 and NaClO4 solutions show that these chaotropic anions also have a strong propensity to form ion networks. The fact that salts containing chaotropic ions like SCN-, BF4 - , and ClO4 - have very high solubility limits in water could then be related to our observation that these chaotropic anions with counter cations in high salt solutions are capable of forming intricate ion networks intertwined with water H-bonding networks. We anticipate that the present graph theoretical analysis

  1. Asymmetric Functional Conversion of Eubacterial Light-driven Ion Pumps.

    Science.gov (United States)

    Inoue, Keiichi; Nomura, Yurika; Kandori, Hideki

    2016-05-06

    In addition to the well-known light-driven outward proton pumps, novel ion-pumping rhodopsins functioning as outward Na(+) and inward Cl(-) pumps have been recently found in eubacteria. They convert light energy into transmembrane electrochemical potential difference, similar to the prototypical archaeal H(+) pump bacteriorhodopsin (BR) and Cl(-) pump halorhodopsin (HR). The H(+), Na(+), and Cl(-) pumps possess the conserved respective DTE, NDQ, and NTQ motifs in the helix C, which likely serve as their functional determinants. To verify this hypothesis, we attempted functional interconversion between selected pumps from each category by mutagenesis. Introduction of the proton-pumping motif resulted in successful Na(+) → H(+) functional conversion. Introduction of the respective characteristic motifs with several additional mutations leads to successful Na(+) → Cl(-) and Cl(-) → H(+) functional conversions, whereas remaining conversions (H(+) → Na(+), H(+) → Cl(-), Cl(-) → Na(+)) were unsuccessful when mutagenesis of 4-6 residues was used. Phylogenetic analysis suggests that a H(+) pump is the common ancestor of all of these rhodopsins, from which Cl(-) pumps emerged followed by Na(+) pumps. We propose that successful functional conversions of these ion pumps are achieved exclusively when mutagenesis reverses the evolutionary amino acid sequence changes. Dependence of the observed functional conversions on the direction of evolution strongly suggests that the essential structural mechanism of an ancestral function is retained even after the gain of a new function during natural evolution, which can be evoked by a few mutations. By contrast, the gain of a new function needs accumulation of multiple mutations, which may not be easily reproduced by limited mutagenesis in vitro.

  2. Laboratory study of ion and electron dynamics during asymmetric magnetic reconnection

    Science.gov (United States)

    Yoo, J.; Jara-Almonte, J.; Yamada, M.; Ji, H.; Fox, W. R., II; Chen, L. J.; Roytershteyn, V.; Na, B.

    2015-12-01

    Magnetic reconnection at the dayside magnetopause has a large density asymmetry across the current sheet. To study effects of the density asymmetry on the ion and electron dynamics, plasmas with a significant (~10) density asymmetry are created in the Magnetic Reconnection Experiment (MRX) [1]. The density asymmetry affects the ion flow pattern by changing the in-plane electrostatic field such that the potential decrease on the high-density side becomes much smaller than that on the low-density side [2]. The ion inflow stagnation point is shifted toward the low-density side and the maximum ion outflow velocity is observed on the low-density side. The density asymmetry also makes the electron temperature profile asymmetric, which has a higher temperature near the low-density-side separatrices. The bulk electron heating is proportional to the total incoming magnetic energy per particle. The electron energization process during asymmetric reconnection is studied via numerical simulations. By comparing 2D simulations with corresponding 3D simulations, we find that the overall energization process does not depend on variations along the third dimension. Where and how electrons are energized during asymmetric reconnection will be discussed by using data from 2D numerical simulations. Finally, the scaling of the reconnection rate and the ion outflow speed given by the Cassak and Shay 2007 [3] is tested by systematically varying the density ratio. The measured ion outflow speed is about 40% of the theoretical values and the measured reconnection rate agrees with the scaling only with the measured density in the exhaust region. [1] M. Yamada et al., Phys. Plasmas 4, 1936 (1997). [2] J. Yoo et al., Phys. Rev. Lett. 113, 095002 (2014). [3] P. Cassak and M. Shay, Phys. Plasmas 14, 102114 (2007).

  3. Structure, Ion Transport, and Rheology of Nanoparticle Salts

    KAUST Repository

    Wen, Yu Ho

    2014-07-08

    Above a critical surface chemistry-dependent particle loading associated with nanoscale interparticle spacing, ligand-ligand interactions-both electrostatic and steric-come into play and govern the structure and dynamics of charged oligomer-functionalized nanoparticle suspensions. We report in particular on the structure, ion transport, and rheology of suspensions of nanoparticle salts created by cofunctionalization of silica particles with tethered sulfonate salts and oligomers. Dispersion of the hairy ionic particles into medium and high dielectric constant liquids yields electrolytes with unique structure and transport properties. We find that electrostatic repulsion imparted by ion dissociation can be tuned to control the dispersion state and rheology through counterion size (i.e., Li+, Na+, and K+) and dielectric properties of the dispersing medium. Analysis of small-angle X-ray scattering (SAXS) structure factors and the mechanical modulus shows that when the interparticle spacing approaches nanometer dimensions, weakly entangled anchored ligands experience strong and long-lived topological constraints analogous to those normally found in well-entangled polymeric fluids. This finding provides insight into the molecular origins of the surprisingly similar rubbery plateau moduli observed in hairy nanoparticle suspensions and entangled polymers of the same chemistry as the tethered ligands. Additionally, we find that a time-composition superposition (TCS) principle exists for the suspensions, which can be used to substantially extend the observation time over which dynamics are observed in jammed, soft glassy suspensions. Application of TCS reveals dynamical similarities between the suspensions and entangled solutions of linear polymer chains; i.e., a hairy particle trapped in a cage appears to exhibit analogous dynamics to a long polymer chain confined to a tube. © 2014 American Chemical Society.

  4. Ion aggregation in high salt solutions. V. Graph entropy analyses of ion aggregate structure and water hydrogen bonding network

    Science.gov (United States)

    Choi, Jun-Ho; Cho, Minhaeng

    2016-05-01

    Dissolved ions in water tend to form polydisperse ion aggregates such as ion pairs, relatively compact ion clusters, and even spatially extended ion networks with increasing salt concentration. Combining molecular dynamics simulation and graph theoretical analysis methods, we recently studied morphological structures of ion aggregates with distinctively different characteristics. They can be distinguished from each other by calculating various spectral graph theoretical properties such as eigenvalues and eigenvectors of adjacency matrices of ion aggregates and water hydrogen-bonding networks, minimum path lengths, clustering coefficients, and degree distributions. Here, we focus on percolation and graph entropic properties of ion aggregates and water hydrogen-bonding networks in high salt solutions. Ion network-forming K+ and SCN- ions at high concentrations show a percolating behavior in their aqueous solutions, but ion cluster-forming ions in NaCl solutions do not show such a transition from isolated ion aggregates to percolating ion-water mixture morphology. Despite that the ion aggregate structures are strikingly different for either cluster- or network-forming ions in high salt solutions, it is interesting that the water structures remain insensitive to the electrostatic properties, such as charge densities and polydentate properties, of dissolved ions, and morphological structures of water H-bonding networks appear to be highly robust regardless of the nature and concentration of salt. We anticipate that the present graph entropy analysis results would be of use in understanding a variety of anomalous behaviors of interfacial water around biomolecules as well as electric conductivities of high electrolyte solutions.

  5. Ion pairing and phase behaviour of an asymmetric restricted primitive model of ionic liquids

    Science.gov (United States)

    Lu, Hongduo; Li, Bin; Nordholm, Sture; Woodward, Clifford E.; Forsman, Jan

    2016-12-01

    An asymmetric restricted primitive model (ARPM) of electrolytes is proposed as a simple three parameter (charge q, diameter d, and charge displacement b) model of ionic liquids and solutions. Charge displacement allows electrostatic and steric interactions to operate between different centres, so that orientational correlations arise in ion-ion interactions. In this way the ionic system may have partly the character of a simple ionic fluid/solid and of a polar fluid formed from ion pairs. The present exploration of the system focuses on the ion pair formation mechanism, the relative concentration of paired and free ions and the consequences for the cohesive energy, and the tendency to form fluid or solid phase. In contrast to studies of similar (though not identical) models in the past, we focus on behaviours at room temperature. By MC and MD simulations of such systems composed of monovalent ions of hard-sphere (or essentially hard-sphere) diameter equal to 5 Å and a charge displacement ranging from 0 to 2 Å from the hard-sphere origin, we find that ion pairing dominates for b larger than 1 Å. When b exceeds about 1.5 Å, the system is essentially a liquid of dipolar ion pairs with a small presence of free ions. We also investigate dielectric behaviours of corresponding liquids, composed of purely dipolar species. Many basic features of ionic liquids appear to be remarkably consistent with those of our ARPM at ambient conditions, when b is around 1 Å. However, the rate of self-diffusion and, to a lesser extent, conductivity is overestimated, presumably due to the simple spherical shape of our ions in the ARPM. The relative simplicity of our ARPM in relation to the rich variety of new mechanisms and properties it introduces, and to the numerical simplicity of its exploration by theory or simulation, makes it an essential step on the way towards representation of the full complexity of ionic liquids.

  6. Estimation of electric conductivity of the quark gluon plasma via asymmetric heavy-ion collisions

    CERN Document Server

    Hirono, Yuji; Hirano, Tetsufumi

    2012-01-01

    We show that in asymmetric heavy-ion collisions, especially off-central Cu+Au collisions, a sizable strength of electric field directed from Au nucleus to Cu nucleus is generated in the overlapping region, because of the difference in the number of electric charges between the two nuclei. This electric field would induce an electric current in the matter created after the collision, which result in a dipole deformation of the charge distribution. The directed flow parameters $v_1^{\\pm}$ of charged particles turn out to be sensitive to the charge dipole and provide us with information about electric conductivity of the quark gluon plasma.

  7. Crystalline Silicotitanate Ion Exchange Support for Salt-Alternatives

    Energy Technology Data Exchange (ETDEWEB)

    Fondeur, F.F.

    2001-02-23

    The current version of crystalline silicotitanate (TAM5) is commercially available from UOP under the trade name IONSIV IE-911. TAM5 was extensively tested by several researchers and was determined as the best currently available material for removing radioisotopes from various types of nuclear wastes salt solutions stored at various DOE sites. The studies at Savannah River Technology Center (SRTC) indicated that the CST granules tend to leach into the nuclear waste simulants as it is processed by the ion exchange columns that is packed with CST granules from UOP. We, at Texas A and M University, agreed to conduct research to compliment the efforts at SRTC so that IONSIV IE-911 could be used for the treatment of nuclear waste stored at the DOE Savannah River facility. After consultation, we developed a Task Plan in January 2000. According to the agreement between Westinghouse Savannah River Company, Savannah River Technology Center, Aiken SC 29808 and, College Station, TX 77843, synthesis and the performance evaluations of crystalline silicotitanates (CST) were performed the during period of April 1 - September 30, 2000. Our main goals were delivery of a kilogram of CST (TAM5-4) synthesized at Texas A and M University in July to SRTC, performance evaluation of CST in nuclear waste simulants, and consultation mainly by telephone.

  8. Systematization of the mass spectra for speciation of inorganic salts with static secondary ion mass spectrometry.

    Science.gov (United States)

    Van Ham, Rita; Van Vaeck, Luc; Adams, Freddy C; Adriaens, Annemie

    2004-05-01

    The analytical use of mass spectra from static secondary ion mass spectrometry for the molecular identification of inorganic analytes in real life surface layers and microobjects requires an empirical insight in the signals to be expected from a given compound. A comprehensive database comprising over 50 salts has been assembled to complement prior data on oxides. The present study allows the systematic trends in the relationship between the detected signals and molecular composition of the analyte to be delineated. The mass spectra provide diagnostic information by means of atomic ions, structural fragments, molecular ions, and adduct ions of the analyte neutrals. The prediction of mass spectra from a given analyte must account for the charge state of the ions in the salt, the formation of oxide-type neutrals from oxy salts, and the occurrence of oxidation-reduction processes.

  9. Mechanical and Thermal Properties of Compression Molded Poly (acrylic acid) Salts with Multivalent Metal Ions

    OpenAIRE

    Gotoh, Y.; Ohkoshi, Y; Nagura, M

    1999-01-01

    Films of zinc, calcium and aluminum salts of poly (acrylic acid) (PAA) were prepared from their powdery salts by compression molding at 190_??_200°C, 600MPa for 0.5hr and their mechanical and thermal properties were investigated. From the results of the dynamic mechanical thermal analysis the storage modulus of each PAA salts exhibited about 20GPa at room temperature because of highly intermolecular crosslinking of PAA by metal ions. Modulus of PAA calcium salt was 7GPa even at 400°C, while m...

  10. Mathematical modeling of salt-gradient ion-exchange simulated moving bed chromatography for protein separations

    Institute of Scientific and Technical Information of China (English)

    卢建刚

    2004-01-01

    The salt-gradient operation mode used in ion-exchange simulated moving bed chromatography (SMBC) can improve the efficiency of protein separations. A detailed model that takes into account any kind of adsorption/ion-exchange equilibrium, salt gradient, size exclusion, mass transfer resistance, and port periodic switching mechanism, was developed to simulate the complex dynamics. The model predictions were verified by the experimental data on upward and downward gradients for protein separations reported in the literature. All design and operating parameters (number, configuration, length and diameter of columns, particle size, switching period, flow rates of feed, raffinate, desorbent and extract, protein concentrations in feed, different salt concentrations in desorbent and feed) can be chosen correctly by numerical simulation. This model can facilitate the design, operation, optimization, control and scale-up of salt-gradient ion-exchange SMBC for protein separations.

  11. Separation and identification of isomeric glycopeptides by high field asymmetric waveform ion mobility spectrometry.

    Science.gov (United States)

    Creese, Andrew J; Cooper, Helen J

    2012-03-01

    The analysis of intact glycopeptides by mass spectrometry is challenging due to the numerous possibilities for isomerization, both within the attached glycan and the location of the modification on the peptide backbone. Here, we demonstrate that high field asymmetric wave ion mobility spectrometry (FAIMS), also known as differential ion mobility, is able to separate isomeric O-linked glycopeptides that have identical sequences but differing sites of glycosylation. Two glycopeptides from the glycoprotein mucin 5AC, GT(GalNAc)TPSPVPTTSTTSAP and GTTPSPVPTTST(GalNAc)TSAP (where GalNAc is O-linked N-acetylgalactosamine), were shown to coelute following reversed-phase liquid chromatography. However, FAIMS analysis of the glycopeptides revealed that the compensation voltage ranges in which the peptides were transmitted differed. Thus, it is possible at certain compensation voltages to completely separate the glycopeptides. Separation of the glycopeptides was confirmed by unique reporter ions produced by supplemental activation electron transfer dissociation mass spectrometry. These fragments also enable localization of the site of glycosylation. The results suggest that glycan position plays a key role in determining gas-phase glycopeptide structure and have implications for the application of FAIMS in glycoproteomics.

  12. Potentiometric Sensor for Real-Time Monitoring of Multivalent Ion Concentrations in Molten Salt

    Energy Technology Data Exchange (ETDEWEB)

    Peter A. Zink; Jan-Fong Jue; Brenda E. Serrano; Guy L. Fredrickson; Ben F. Cowan; Steven D. Herrmann; Shelly X. Li

    2010-07-01

    Electrorefining of spent metallic nuclear fuel in high temperature molten salt systems is a core technology in pyroprocessing, which in turn plays a critical role in the development of advanced fuel cycle technologies. In electrorefining, spent nuclear fuel is treated electrochemically in order to effect separations between uranium, noble metals, and active metals, which include the transuranics. The accumulation of active metals in a lithium chloride-potassium chloride (LiCl-KCl) eutectic molten salt electrolyte occurs at the expense of the UCl3-oxidant concentration in the electrolyte, which must be periodically replenished. Our interests lie with the accumulation of active metals in the molten salt electrolyte. The real-time monitoring of actinide concentrations in the molten salt electrolyte is highly desirable for controlling electrochemical operations and assuring materials control and accountancy. However, real-time monitoring is not possible with current methods for sampling and chemical analysis. A new solid-state electrochemical sensor is being developed for real-time monitoring of actinide ion concentrations in a molten salt electrorefiner. The ultimate function of the sensor is to monitor plutonium concentrations during electrorefining operations, but in this work gadolinium was employed as a surrogate material for plutonium. In a parametric study, polycrystalline sodium beta double-prime alumina (Na-ß?-alumina) discs and tubes were subject to vapor-phase exchange with gadolinium ions (Gd3+) using a gadolinium chloride salt (GdCl3) as a precursor to produce gadolinium beta double-prime alumina (Gd-ß?-alumina) samples. Electrochemical impedance spectroscopy and microstructural analysis were performed on the ion-exchanged discs to determine the relationship between ion exchange and Gd3+ ion conductivity. The ion-exchanged tubes were configured as potentiometric sensors in order to monitor real-time Gd3+ ion concentrations in mixtures of gadolinium

  13. Highly enantioselective asymmetric autocatalysis using chiral ruthenium complex-ion-exchanged synthetic hectorite as a chiral initiator.

    Science.gov (United States)

    Kawasaki, Tsuneomi; Omine, Toshiki; Suzuki, Kenta; Sato, Hisako; Yamagishi, Akihiko; Soai, Kenso

    2009-03-21

    The synthetic hectorite containing intercalated chiral Delta- and Lambda-tris(1,10-phenanthroline)ruthenium(II) ions acts as a heterogeneous chiral catalyst in the enantioselective addition of diisopropylzinc to pyrimidine-5-carbaldehyde to afford, in combination with asymmetric autocatalytic amplification of enantiomeric excess, 5-pyrimidyl alkanol with high enantiomeric excess.

  14. Polymer-Supported Cinchona Alkaloid-Derived Ammonium Salts as Recoverable Phase-Transfer Catalysts for the Asymmetric Synthesis of α-Amino Acids

    Directory of Open Access Journals (Sweden)

    Carmen Nájera

    2004-04-01

    Full Text Available Alkaloids such as cinchonidine, quinine and N-methylephedrine have been N-alkylated using polymeric benzyl halides or co-polymerized and then N-alkylated, thus affording a series of polymer-supported chiral ammonium salts which have been employed as phase-transfer catalysts in the asymmetric benzylation of an N-(diphenylmethyleneglycine ester. These new polymeric catalysts can be easily recovered by simple filtration after the reaction and reused. The best ee’s were achieved when Merrifield resin-anchored cinchonidinium ammonium salts were employed.

  15. Asymmetric Aldol Reaction Catalyzed by L-Proline and Achiral Thiourea Fluoroboric Acid Salt

    Energy Technology Data Exchange (ETDEWEB)

    Cho, Eun; Lee, Haney; Kim, Taek Hyeon [Chonnam National University, Gwangju (Korea, Republic of)

    2015-01-15

    Considering its ready availability and low cost, L-proline would be the first choice catalyst for preparing aldol adducts with high diastereo- and enantioselectivity. However, proline presents some major drawbacks, including poor performance in direct aldol reactions with aromatic aldehydes, limited solubility, and reactivity in nonpolar organic solvents, and side reactions that make using high catalyst loadings necessary to reach satisfactory conversions. Therefore, numerous proline-modified organo catalysts such as prolinamides, proline thioamides, sulfonamides, chiral amines, and organic salts have been designed for direct aldol reactions. An alternative is to add a readily available additive to the reactions containing proline. This last approach is clearly advantageous in avoiding tedious chemical syntheses of organo catalysts and would ultimately allow the construction of libraries of catalyst protocols by simply changing the additive. Acid additives can influence the outcome of enamine mediated reactions; however, only a few screening studies of acid additions to thiourea organo catalysts are available in the literature. The reaction between cyclohexanone and 4-nitrobenzaldehyde was selected as a standard model reaction for screening of more effective acid additives to thiourea.

  16. Scaling of triple differential cross-sections for asymmetric (, 2) process on helium isoelectronic ions by fast electrons

    Indian Academy of Sciences (India)

    M K Srivastava

    2005-01-01

    A simple scaling law is obtained for asymmetric (, 2) process on helium isoelectronic ions by fast electrons. It is based on treating the targets as having one active electron moving in the effective Coulomb field of the atomic core with an effective charge ' = − 5/8. This effective charge is also used in the description of the scattered and ejected electrons. The model has been tested against other available (, 2) results on helium in asymmetric geometry. The scaling law is found to work reasonably well for fast incident electrons and becomes increasingly accurate as target increases.

  17. Regulation of ion homeostasis by aminolevulinic acid in salt-stressed wheat seedlings

    Science.gov (United States)

    Türk, Hülya; Genişel, Mucip; Erdal, Serkan

    2016-04-01

    Salinity is regarded as a worldwide agricultural threat, as it seriously limits plant development and productivity. Salt stress reduces water uptake in plants by disrupting the osmotic balance of soil solution. In addition, it creates a damaged metabolic process by causing ion imbalance in cells. In this study, we aim to examine the negative effects of 5-aminolevulinic acid (ALA) (20 mg/l) on the ion balance in wheat seedling leaves exposed to salt stress (150 mM). Sodium is known to be highly toxic for plant cells at high concentrations, and is significantly increased by salt stress. However, it can be reduced by combined application of ALA and salt, compared to salt application alone. On the other hand, while the K+/Na+ ratio was reduced by salt stress, ALA application changed this ratio in favor of K+. Manganese, iron, and copper were also able to reduce stress. However, ALA pre-treatment resulted in mineral level increments. Conversely, the stress-induced rise in magnesium, potassium, calcium, phosphorus, zinc, and molybdenum were further improved by ALA application. These data clearly show that ALA has an important regulatory effect of ion balance in wheat leaves.

  18. Can the Transport Properties of Molten Salts and Ionic Liquids Be Used To Determine Ion Association?

    Science.gov (United States)

    Harris, Kenneth R

    2016-12-01

    There have long been arguments supporting the concept of ion association in molten salts and ionic liquids, largely based on differences between the conductivity and that predicted from self-diffusion coefficients by the Nernst-Einstein equation for noninteracting ions. It is known from molecular dynamics simulations that even simple models based on charged hard spheres show such a difference due to the (anti)-correlation of ion motions. Formally this is expressed as a difference between the velocity cross-correlation coefficient of the oppositely charged ions and the mean of those for the two like-charged ions. This article examines molten salt and ionic liquid transport property data, comparing simple and model associated salts (ZnCl2, PbCl2, and TlCl) including weakly dissociated molecular liquids (H2O, HCOOH, H2SO4). Analysis employing Laity resistance coefficients (rij) shows that the common ion-association rationalization is flawed, consistent with recent direct measurements of the degree of ionicity in ionic liquid chlorides and with theoretical studies. However, the protic ionic liquids [PyrOMe][BF4] and [DBUH][CH3SO3] have larger than usual NE deviation parameters (>0.5), and large negative like-ion rii, analogous to those of ZnCl2. Structural, spectroscopic, and theoretical studies are suggested to determine whether these are indeed genuine examples of association.

  19. Photocatalysis-triggered ion rectification in artificial nanochannels based on chemically modified asymmetric TiO2 nanotubes.

    Science.gov (United States)

    Hu, Ziying; Zhang, Qianqian; Gao, Jun; Liu, Zhaoyue; Zhai, Jin; Jiang, Lei

    2013-04-16

    Ion rectification is one of the important characteristics of biological ion channels. Inspired by the function of biological ion channels, creation of artificial nanochannels that show analogous ion rectification characteristics has attracted a great interest recently. Herein, we demonstrate a new type of artificial solid-state nanochannel with ion rectification characteristics. The creation of artificial nanochannels includes the formation of asymmetric TiO2 nanotubes by electrochemical anodization of Ti metal, followed by chemical modification with octadecyltrimethoxysilane (OTS) molecules. The carboxylic groups are introduced onto the tip side of TiO2 nanotubes via photocatalytic decomposition of OTS molecules by TiO2 photocatalysis under ultraviolet light. When the radius of tip side of TiO2 nanotubular channels is comparable to the thickness of electric double layer, the negatively charged surface in neutral electrolyte in combination with the asymmetric pore geometry contributes to the ion rectification characteristics. Compared with previous artificial nanochannels, our new type of artificial nanochannel is more facile to fabricate and behaves as a diode that rectifies the ion transport, which also shows some other potential applications, such as sensor and separation materials.

  20. Investigation of electron localization in harmonic emission from asymmetric molecular ion

    Institute of Scientific and Technical Information of China (English)

    张彩萍; 苗向阳

    2015-01-01

    We theoretically investigate the electron localization around two nuclei in harmonic emission from asymmetric molec-ular ion. The results show that the ionization process of electron localized around one nucleus competes with its transfer process to the other nucleus. By increasing the initial vibrational level, more electrons localized around the nucleus D+tend to transfer to the nucleus He2+so that the ionizations of electrons localized around the nucleus He2+increase. In this case, the difference in harmonic efficiency between HeH2+and HeD2+decreases while the difference in harmonic spectral structure increases. The evident minimum can be observed in the harmonic spectrum of HeH2+ compared with that in the spectral structure of HeD2+, which is due to the strong interference of multiple recombination channels originating from two nuclei. Time-dependent nuclear probability density, electron-nuclear probability density, double-well model, and time-frequency maps are presented to explain the underlying mechanisms.

  1. Impact of flows on ion temperatures inferred from neutron spectra in asymmetrically driven OMEGA DT implosions

    Science.gov (United States)

    Gatu Johnson, M.; Frenje, J. A.; Seguin, F. H.; Petrasso, R. D.; Aappelbe, B.; Chittenden, J.; Walsh, C.; Knauer, J. P.; Glebov, V. Yu.; Forrest, C.; Marshall, F.; Michel, T.; Stoeckl, C.; Sangster, T. C.; Zylstra, A.

    2016-10-01

    Ion temperatures (Tion) in Inertial Confinement Fusion (ICF) experiments have traditionally been inferred from the broadening of primary neutron spectra. Directional motion (flow) of the fuel at burn, expected to arise due to asymmetries imposed by engineering features (such as stalks, fill tubes, tents, or capsule imperfections) or drive non-uniformity, also impacts broadening and may lead to artificially inflated ``Tion'' values. Flow due to low-mode asymmetries is expected to give rise to line-of-sight variations in measured Tion, as observed in OMEGA cryogenic DT implosions but not in similar experiments at the NIF. In this presentation we report on an OMEGA experiment with intentionally asymmetric drive, designed to test the ability to accurately predict and measure line-of-sight differences in apparent Tion due to low-mode asymmetry-seeded flows. The results provide insight into the complexity of hot-spot dynamics, which is a problem that must be mastered to achieve ICF ignition. This work was supported in part by LLE, the U.S. DoE (NNSA, NLUF) and LLNL.

  2. Electrokinetic salt removal from porous building materials using ion exchange membranes

    NARCIS (Netherlands)

    Kamran, K.; Van Soestbergen, M.; Pel, L.

    The removal of salt from porous building materials under the influence of an applied voltage gradient normally results in high pH gradients due to the formation of protons and hydroxyl ions at the electrodes. The formed acidic and alkaline regions not only lead to disintegration of the porous materi

  3. Seed Treatment with Auxins Modulates Growth and Ion Partitioning in Salt-stressed Wheat Plants

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Experiments were performed to determine whether seed priming with different concentrations (100, 150, and 200 mg/L) of auxins (indoleacetic acid (IAA), indolebutyric acid (IBA), or their precursor tryptophane (Trp)) could alter salinity induced perturbances in salicylic acid and ion concentrations and, hence, growth in wheat (Triticum aestivum L.) cultivars, namely M.H.-97 (salt intolerant) and Inqlab-91 (salt tolerant). Primed and non-primed seeds were sown in Petri dishes in a growth room, as well as in a field treated with 15 dS/m NaCl salinity. All priming agents, except IBA, increased the final germination percentage in both cultivars. The seedlings of either cultivar raised from Trp-treated seeds had greater dry biomass when under salt stress. In field experiments, Trp priming was much more effective in mediating the increase in grain yield,irrespective of the cultivar, under salt stress. The alleviatory effect of Trp was found to be associated with reduced uptake of Na+ in the roots and subsequent translocation to the shoots, as well as increased partitioning of Ca2+ in the roots of salt-stressed wheat plants. Plants of both cultivars raised from Trp- and IAA-treated seeds accumulated free salicylic acid in their leaves when under salt stress. Overall, the Trp priming-induced improvement in germination and the subsequent growth of wheat plants could be related to ion homeostasis when under salt stress. The possible involvement of salicylic acid in the Trp priming-induced better growth under conditions of salt stress is discussed.

  4. STUDY ON ION-POLYMER INTERACTION AND MORPHOLOGIC STRUCTURE OF POLYURETHANE/SALT SYSTEMS

    Institute of Scientific and Technical Information of China (English)

    朱卫华; 杨兵; 王新灵; 唐小真

    2001-01-01

    A poly(ethylene oxide) urethane and a model-compound of hard segment(HD) were prepared in this study. Solid polymer electrolytes were got from the blends of polyurethane, HD and NaClO4. The samples were characterized by mean of FT-IR and AFM. Effects of salt concentration on ion-polymer interaction and further on morphologic structure of the composites were investigated and some interesting results were obtained. The results show that HD and concentration of NaClO4 have an important effect on ion-polymer interaction and morphologic structure of the complex. It is also found that in AFM pictures of the samples there is a transition point and ion-polymer interaction of the polyurethane/salt systems play an extremely important role on morphologic structure.

  5. Ion Dynamics Study of Potato Starch + Sodium Salts Electrolyte System

    Directory of Open Access Journals (Sweden)

    Tuhina Tiwari

    2013-01-01

    Full Text Available The effect of different anions, namely, SCN−, I−, and ClO4−, on the electrical properties of starch-based polymer electrolytes has been studied. Anion size and conductivity are having an inverse trend indicating systems to be predominantly anionic conductor. Impact of anion size and multiplet forming tendency is reflected in number of charge carriers and mobility, respectively. Ion dynamics study reveals the presence of different mechanisms in different frequency ranges. Interestingly, superlinear power law (SLPL is found to be present at <5 MHz frequency, which is further confirmed by dielectric data.

  6. The acute toxicity of major ion salts to Ceriodaphnia dubia: I. ...

    Science.gov (United States)

    The ions Na+, K+, Ca2+, Mg2+, Cl-, SO42-, and HCO3-/CO32- (referred to as “major ions”) are present in all fresh waters and are physiologically required by aquatic organisms, but can be increased to harmful levels by a variety of anthropogenic activities that speed geochemical weathering or otherwise introduce or concentrate ions. While toxicity of these ions to aquatic organisms has been previously shown, it is also known that their toxicity can vary depending on the concentrations of other co-occurring anions, and understanding these relationships is key to predicting toxicity and establishing appropriate environmental limits. In this paper we conduct a series of experiments with Ceriodaphnia dubia to evaluate the acute toxicity of all twelve major ionsalts (pairing one of the cations with one of the anions) and to determine how toxicity of these salts varies as a function of background water chemistry. All salts except CaSO4 and CaCO3 were acutely toxic to C. dubia below saturation, with the lowest LC50s found for K salts. Of the remaining salts, all but CaCl2 showed some degree of decreased toxicity as the ionic content of the background water increased. Experiments that independently varied Ca:Mg ratio, Na:K ratio, Cl:SO4 ratio, and alkalinity/pH were used to show that Ca concentration was the primary factor influencing the toxicities of Na and Mg salts. In contrast, the toxicities of K salts were primarily influenced by the concentration of Na. Th

  7. Transport of ions and biomolecules through single asymmetric nanopores in polymer films

    Science.gov (United States)

    Schiedt, Birgitta; Healy, Ken; Morrison, Alan P.; Neumann, Reinhard; Siwy, Zuzanna

    2005-07-01

    Single conical nanopores in polymer foils show 'rectifying' diode-like current-voltage (I-V) characteristics, with preferential cation flow in the direction from the narrow to the wide opening [P. Apel, Y.E. Korchev, Z. Siwy, R. Spohr, M. Yoshida, Nucl. Instr. and Meth. B 184 (2001) 337-346, Z. Siwy, D. Dobrev, R. Neumann, C. Trautmann, K. Voss, Appl. Phys. A 76 (2003) 781-785]. To produce single-pore membranes, we irradiated polymer films (polyethylene terephthalate and polyimide) with single heavy ions (using kinetic energies in the GeV range) and subsequently performed asymmetric chemical track-etching. The resulting conical pores had narrow openings of 4-20 nm. The I-V curves of these pores were measured in aqueous KCl solutions of various concentrations and pH values, and it was found that both parameters influence the rectification properties of the pores. For decreasing concentrations, down to 0.1 M, the degree of rectification increases, as predicted by a recently proposed model [Z. Siwy, A. Fulinski, Phys. Rev. Lett. 89 (2002) 198103], however, as the concentration decreases further, the rectification unexpectedly begins to decrease again. We suspect that this is due to conformation changes occurring in the pore. Also, our results have shown that the pores exhibit a non-classical conductance versus electrolyte concentration characteristic, having elevated conductances at low concentrations, for which we propose an explanation based on surface conductivity. Finally, we present an application of the polyimide conical nanopores as single-molecule DNA sensors, with results demonstrating their ability to detect individual plasmid DNA molecules.

  8. Effect of Salt Stress on Transpiration and Ion Distribution in Seedlings of Four Tree Species

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Transpiration rate and ion distribution of pagoda tree, walnut, velvet ash and poplar seedlings treated by NaCl solution of 0, 50, 100, 200 mmol·L-1 were studied. The results showed that there were significant differences in the response to NaCl among the four tree species. Na+ exclusion capacity of pagoda tree was the largest among the four species. The Na+ exclusion capacity of velvet ash was less than that of pagoda tree. Salt excretion capacity of velvet ash was limited. Its salt-tolerance was bigge...

  9. LiGa(OTf)(sub 4) as an Electrolyte Salt for Li-Ion Cells

    Science.gov (United States)

    Reddy, V. Prakash; Prakash, G. K. Syria; Hu, Jinbo; Yan, Ping; Smart, Marshall; Bugga, ratnakumar; Chin, Keith; Surampudi, Subarao

    2008-01-01

    Lithium tetrakis(trifluoromethane sulfo - nato)gallate [abbreviated "LiGa(OTf)4" (wherein "OTf" signifies trifluoro - methanesulfonate)] has been found to be promising as an electrolyte salt for incorporation into both liquid and polymer electrolytes in both rechargeable and non-rechargeable lithium-ion electrochemical cells. This and other ingredients have been investigated in continuing research oriented toward im proving the performances of rechargeable lithium-ion electrochemical cells, especially at low temperatures. This research at earlier stages, and the underlying physical and chemical principles, were reported in numerous previous NASA Tech Briefs articles. As described in more detail in those articles, lithiumion cells most commonly contain nonaqueous electrolyte solutions consisting of lithium hexafluorophosphate (LiPF6) dissolved in mixtures of cyclic and linear alkyl carbonates, including ethylene carbonate (EC), propylene carbonate (PC), dimethyl carbonate (DMC), diethyl carbonate (DEC), and ethyl methyl carbonate (EMC). Although such LiPF6-based electrolyte solutions are generally highly ionically conductive and electrochemically stable, as needed for good cell performance, there is interest in identifying alternate lithium electrolyte salts that, relative to LiPF6, are more resilient at high temperature and are less expensive. Experiments have been performed on LiGa(OTf)4 as well as on several other candidate lithium salts in pursuit of this interest. As part of these experiments, LiGa(OTf)4 was synthesized by the reaction of Ga(OTf)3 with an equimolar portion of LiOTf in a solvent consisting of anhydrous acetonitrile. Evaporation of the solvent yielded LiGa(OTf)4 as a colorless crystalline solid. The LiGa(OTf)4 and the other salts were incorporated into solutions with PC and DMC. The resulting electrolyte solutions exhibited reasonably high ionic conductivities over a relatively wide temperature range down to 40 C (see figure). In cyclic

  10. Recycling asymmetric hydrogenation catalysts by their immobilisation onto ion-exchange resins.

    Science.gov (United States)

    Barbaro, Pierluigi; Bianchini, Claudio; Giambastiani, Giuliano; Oberhauser, Werner; Bonzi, Laura Morassi; Rossi, Filippo; Dal Santo, Vladimiro

    2004-06-21

    New systems based on cationic chiral phosphine-rhodium complexes anchored to a commercial cation-exchange gel-type resin showed high efficiency and easy recycling in the asymmetric hydrogenation of prochiral olefins.

  11. Effects of ion exchange on stream solute fluxes in a basin receiving highway deicing salts

    Science.gov (United States)

    Shanley, J.B.

    1994-01-01

    At Fever Brook, a 1260-ha forested basin in central Massachusetts, highway deicing salt application increased the solute flux in streamflow by 120% above background flux (equivalent basis) during a 2-yr period. Attempts to isolate the nonsalt component of stream solute fluxes have commonly subtracted salt contributions based on the net Cl flux (Cl output in streamflow minus Cl input in precipitation). In these studies, any net Na flux in excess of the amount needed to balance the net Cl flux has been attributed to weathering. At Fever Brook, however, the net output of Na was less than the net output of Cl, suggesting a loss of Na within the basin. The Na sink was inferred to be cation exchange of Na for Ca and Mg in the soil. A method was developed to quantify the exchange based on a Na budget, which included an independent estimate of the Na flux from weathering. The amount of exchange was apportioned to Ca and Mg based on their relative concentrations in the stream. The background fluxes of Ca and Mg (i.e., those that would occur in the absence of deicing salts) were calculated by subtracting the amounts from ion exchange plus the much smaller direct contributions in deicing salts from the observed fluxes. Ion exchange and direct salt contributions increased the net output fluxes of Ca and Mg, each by 44% above background. In basins that receive deicing salts, failure to account for cation exchange thus may result in an underestimate of the flux of Na from weathering and overestimates of the fluxes of Ca and Mg from weathering.

  12. Molten Salt Electrolytically Produced Carbon/Tin Nanomaterial as the Anode in a Lithium Ion Battery

    Science.gov (United States)

    Das Gupta, Rajshekar; Schwandt, Carsten; Fray, Derek J.

    2017-03-01

    A carbon/tin nanomaterial, consisting of predominantly Sn-filled carbon nanotubes and nanoparticles, is prepared by molten salt electrochemistry, using electrodes of graphite and an electrolyte of LiCl salt containing a small admixture of SnCl2. The C/Sn hybrid material generated is incorporated into the active anode material of a lithium ion battery and tested with regard to storage capacity and cycling behavior. The results demonstrate that the C/Sn material has favorable properties, in terms of energy density and in particular long-term stability, that exceed those of the individual components alone. The initial irreversible capacity of the material is somewhat larger than that of conventional battery graphite which is due to its unique nanostructure. Overall the results would indicate the suitability of this material for use in the anodes of lithium ion batteries with high rate capability.

  13. Molten Salt Electrolytically Produced Carbon/Tin Nanomaterial as the Anode in a Lithium Ion Battery

    Science.gov (United States)

    Das Gupta, Rajshekar; Schwandt, Carsten; Fray, Derek J.

    2016-12-01

    A carbon/tin nanomaterial, consisting of predominantly Sn-filled carbon nanotubes and nanoparticles, is prepared by molten salt electrochemistry, using electrodes of graphite and an electrolyte of LiCl salt containing a small admixture of SnCl2. The C/Sn hybrid material generated is incorporated into the active anode material of a lithium ion battery and tested with regard to storage capacity and cycling behavior. The results demonstrate that the C/Sn material has favorable properties, in terms of energy density and in particular long-term stability, that exceed those of the individual components alone. The initial irreversible capacity of the material is somewhat larger than that of conventional battery graphite which is due to its unique nanostructure. Overall the results would indicate the suitability of this material for use in the anodes of lithium ion batteries with high rate capability.

  14. Asymmetric bipolar membranes in acid-base electrodialysis

    NARCIS (Netherlands)

    Wilhelm, Friedrich G.; Punt, Ineke; Vegt, van der Nico F.A.; Strathmann, H.; Wessling, M.

    2002-01-01

    In this experimental study, the influence of asymmetric bipolar membranes on the salt impurities in the acid and base product is investigated. The thickness of one, the other, or both ion-permeable layers of a bipolar membrane is increased. With increased layer thickness, the current-voltage curves

  15. Modeling of salt and pH gradient elution in ion-exchange chromatography.

    Science.gov (United States)

    Schmidt, Michael; Hafner, Mathias; Frech, Christian

    2014-01-01

    The separation of proteins by internally and externally generated pH gradients in chromatofocusing on ion-exchange columns is a well-established analytical method with a large number of applications. In this work, a stoichiometric displacement model was used to describe the retention behavior of lysozyme on SP Sepharose FF and a monoclonal antibody on Fractogel SO3 (S) in linear salt and pH gradient elution. The pH dependence of the binding charge B in the linear gradient elution model is introduced using a protein net charge model, while the pH dependence of the equilibrium constant is based on a thermodynamic approach. The model parameter and pH dependences are calculated from linear salt gradient elutions at different pH values as well as from linear pH gradient elutions at different fixed salt concentrations. The application of the model for the well-characterized protein lysozyme resulted in almost identical model parameters based on either linear salt or pH gradient elution data. For the antibody, only the approach based on linear pH gradients is feasible because of the limited pH range useful for salt gradient elution. The application of the model for the separation of an acid variant of the antibody from the major monomeric form is discussed.

  16. Understanding the role of ion interactions in soluble salt flotation with alkylammonium and alkylsulfate collectors.

    Science.gov (United States)

    Ozdemir, Orhan; Du, Hao; Karakashev, Stoyan I; Nguyen, Anh V; Celik, M S; Miller, Jan D

    2011-03-15

    There is anecdotal evidence for the significant effects of salt ions on the flotation separation of minerals using process water of high salt content. Examples include flotation of soluble salt minerals such as potash, trona and borax in brine solutions using alkylammonium and alkylsulfate collectors such as dodecylamine hydrochloride and sodium dodecylsulfate. Although some of the effects are expected, some do not seem to be encompassed by classical theories of colloid science. Several experimental and modeling techniques for determining solution viscosity, surface tension, bubble-particle attachment time, contact angle, and molecular dynamics simulation have been used to provide further information on air-solution and solid-solution interfacial phenomena, especially with respect to the interfacial water structure due to the presence of dissolved ions. In addition atomic force microscopy, and sum frequency generation vibrational spectroscopy have been used to provide further information on surface states. These studies indicate that the ion specificity effect is the most significant factor influencing flotation in brine solutions.

  17. Comparative Salt Stress Study on Intracellular Ion Concentration in Marine and Salt-adapted Freshwater Strains of Microalgae

    Directory of Open Access Journals (Sweden)

    Ahmad Farhad TALEBI

    2013-08-01

    Full Text Available Salinity imposes significant stresses in various living organisms including microalgae. High extracellular concentration of Na+ directly influences ionic balance inside the cell and subsequently the cellular activities. In the present study, the effect of such stress on growth and intracellular ions concentration (IIC of Dunaliella salina and Chlorella Spp. was investigated. IIC was analyzed using Ion chromatography technique. D. salina showed the highest degree of resistance to increase in salinity as little changes occurred both in IIC and in growth parameters. D. salina could maintain the balance of K+ inside the cell and eject the excess Na+ even at NaCl concentrations above 1M. Moreover, D. salina accumulated β-carotene in order to protect its photosynthetic apparatus. Among Chlorella species, C. vulgaris showed signs of adaptation to high content of salinity, though it is a fresh water species by nature. Moreover, the response shown by C. vulgaris to rise in salinity was even stronger than that of C. salina, which is presumably a salt-water resistant species. In fact, C. vulgaris could maintain intracellular K+ better than C. salina in response to increasing salinity, and as a result, it could survive at NaCl concentrations as high as 0.75 M. Marine strains such as D. salina well cope with the fluctuations in salinity through the existing adaptation mechanisms i.e. maintaining the K+/N+ balance inside the cell, K+ accumulation and Na+ ejection, accumulation of photosynthetic pigments like β-carotene.

  18. Fluxes of microbes, organic aerosols, dust, sea-salt Na ions, non-sea-salt Ca ions, and methanesulfonate onto Greenland and Antarctic ice

    Directory of Open Access Journals (Sweden)

    P. B. Price

    2009-03-01

    Full Text Available Using a spectrofluorimeter with 224-nm laser excitation and six emission bands from 300 to 420 nm to measure fluorescence intensities at 0.3-mm depth intervals in ice cores, we report results of the first comparative study of concentrations of microbial cells (using the spectrum of protein-bound tryptophan (Trp as a proxy and of aerosols with autofluorescence spectra different from Trp (denoted "non-Trp" as a function of depth in ice cores from West Antarctica (WAIS Divide and Siple Dome and Greenland (GISP2. The ratio of fluxes of microbial cells onto West Antarctic (WAIS Divide versus Greenland sites is 0.13±0.06; the ratio of non-Trp aerosols onto WAIS Divide versus Greenland sites is 0.16±0.08; and the ratio of non-sea-salt Ca2+ ions (a proxy for dust grains onto WAIS Divide versus Greenland sites is 0.06±0.03. All of these are roughly comparable to the ratio of fluxes of dust onto Antarctic versus Greenland sites (0.08±0.05. By contrast to those values, which are considerably lower than unity, the ratio of fluxes of methanesulfonate (MSA onto Antarctic versus Greenland sites is 1.9±0.4 and the ratio of sea-salt Na2+ ions onto WAIS Divide versus Greenland sites is 3.0±2. These ratios are more than an order of magnitude higher than those in the first grouping. We infer that the correlation of microbes and non-Trp aerosols with non-sea-salt Ca and dust suggests a largely terrestrial rather than marine origin. The lower fluxes of microbes, non-Trp aerosols, non-sea-salt Ca and dust onto WAIS Divide ice than onto Greenland ice may be due to the smaller areas of their source regions and less favorable wind patterns for transport onto Antarctic ice than onto Greenland ice. The correlated higher relative fluxes of MSA and marine Na onto Antarctic versus Greenland ice is consistent with the view that both originate largely on or around sea ice, with the Antarctic sea ice being far more extensive than that around Greenland.

  19. Salt bridges destabilize a leucine zipper designed for maximized ion pairing between helices.

    Science.gov (United States)

    Phelan, Paul; Gorfe, Alemayehu A; Jelesarov, Ilian; Marti, Daniel N; Warwicker, James; Bosshard, Hans Rudolf

    2002-03-05

    Interhelical salt bridges are common in leucine zippers and are thought to stabilize the coiled coil conformation. Here we present a detailed thermodynamic investigation of the designed, disulfide-linked leucine zipper AB(SS) whose high-resolution NMR structure shows six interhelical ion pairs between heptad positions g of one helix and e' of the other helix but no ion pairing within single helices. The average pK(a) value of the Glu side chain carboxyl groups of AB(SS) is slightly higher than the pK(a) of a freely accessible Glu in an unfolded peptide [Marti, D. N., Jelesarov, I., and Bosshard, H. R. (2000) Biochemistry 39, 12804-12818]. This indicates that the salt bridges are destabilizing, a prediction we now have confirmed by determining the pH +/- stability profile of AB(SS). Circular dichroism-monitored unfolding by urea and by heating and differential scanning calorimetry show that the coiled coil conformation is approximately 5 kJ/mol more stable when salt bridges are broken by protonation of the carboxyl side chains. Using guanidinium chloride as the denaturant, the increase in the free energy of unfolding on protonation of the carboxyl side chains is larger, approximately 17 kJ/mol. The discrepancy between urea and guanidinium chloride unfolding can be ascribed to the ionic nature of guanidinium chloride, which screens charge-charge interactions. This work demonstrates the difficulty of predicting the energetic contribution of salt bridges from structural data alone even in a case where the ion pairs are seen in high-resolution NMR structures. The reason is that the contribution to stability results from a fine balance between energetically favorable Coulombic attractions and unfavorable desolvation of charges and conformational constraints of the residues involved in ion pairing. The apparent discrepancy between the results presented here and mutational studies indicating stabilization by salt bridges is discussed and resolved. An explanation is

  20. Separation of Opiate Isomers Using Electrospray Ionization and Paper Spray Coupled to High-Field Asymmetric Waveform Ion Mobility Spectrometry

    Science.gov (United States)

    Manicke, Nicholas E.; Belford, Michael

    2015-05-01

    One limitation in the growing field of ambient or direct analysis methods is reduced selectivity caused by the elimination of chromatographic separations prior to mass spectrometric analysis. We explored the use of high-field asymmetric waveform ion mobility spectrometry (FAIMS), an ambient pressure ion mobility technique, to separate the closely related opiate isomers of morphine, hydromorphone, and norcodeine. These isomers cannot be distinguished by tandem mass spectrometry. Separation prior to MS analysis is, therefore, required to distinguish these compounds, which are important in clinical chemistry and toxicology. FAIMS was coupled to a triple quadrupole mass spectrometer, and ionization was performed using either a pneumatically assisted heated electrospray ionization source (H-ESI) or paper spray, a direct analysis method that has been applied to the direct analysis of dried blood spots and other complex samples. We found that FAIMS was capable of separating the three opiate structural isomers using both H-ESI and paper spray as the ionization source.

  1. Scaling of cross-sections for asymmetric (, 3) process on helium-like ions by fast electrons

    Indian Academy of Sciences (India)

    M K Srivastava

    2004-11-01

    An approximate simple scaling law is obtained for asymmetric (, 3) process on helium-like ions for double ionization by fast electrons. It is based on the equation $(Z'^{3} /)$ exp$[−Z' (r_{1} + r_{2})]$, $Z' = Z − (5/16)$ for ground state wave function of helium- like ions and $Z'^{2}$ scaling of energies. The scaling law is found to work very well if the lower energy electron is ejected along the momentum transfer direction and the other one is ejected in the opposite direction. It also works quite well if this electron is ejected within about 90° of the momentum transfer direction with the other electron going in the opposite direction. The scaling law becomes increasingly accurate as the target nuclear charge and the energy increase.

  2. Towards more thermally stable Li-ion battery electrolytes with salts and solvents sharing nitrile functionality

    Science.gov (United States)

    Kerner, Manfred; Lim, Du-Hyun; Jeschke, Steffen; Rydholm, Tomas; Ahn, Jou-Hyeon; Scheers, Johan

    2016-11-01

    The overall safety of Li-ion batteries is compromised by the state-of-the-art electrolytes; the thermally unstable lithium salt, lithium hexafluorophosphate (LiPF6), and flammable carbonate solvent mixtures. The problem is best addressed by new electrolyte compositions with thermally robust salts in low flammability solvents. In this work we introduce electrolytes with either of two lithium nitrile salts, lithium 4,5-dicyano-1,2,3-triazolate (LiDCTA) or lithium 4,5-dicyano-2-trifluoromethylimidazolide (LiTDI), in solvent mixtures with high flashpoint adiponitrile (ADN), as the main component. With sulfolane (SL) and ethylene carbonate (EC) as co-solvents the liquid temperature range of the electrolytes are extended to lower temperatures without lowering the flashpoint, but at the expense of high viscosities and moderate ionic conductivities. The anodic stabilities of the electrolytes are sufficient for LiFePO4 cathodes and can be charged/discharged for 20 cycles in Li/LiFePO4 cells with coulombic efficiencies exceeding 99% at best. The excellent thermal stabilities of the electrolytes with the solvent combination ADN:SL are promising for future electrochemical investigations at elevated temperatures (> 60 °C) to compensate the moderate transport properties and rate capability. The electrolytes with EC as a co-solvent, however, release CO2 by decomposition of EC in presence of a lithium salt, which potentially makes EC unsuitable for any application targeting higher operating temperatures.

  3. Changes in transcript related to osmosis and intracellular ion homeostasis in Paulownia tomentosa under salt stress

    Directory of Open Access Journals (Sweden)

    Guoqiang eFan

    2016-03-01

    Full Text Available Paulownia tomentosa is an important economic and greening tree species that is cultivated widely, including salt environment. Our previous studies indicated its autotetraploid induced by colchicine showed better stress tolerance, but the underlying molecular mechanism related to ploidy and salt stress is still unclear. To investigate this issue, physiological measurements and transcriptome profiling of diploid and autotetraploid plants untreated and treated with NaCl were performed. Through the comparisons among four accessions, for one thing, we found different physiological changes between diploid and autotetraploid P. tomentosa; for another, and we detected many differentially expressed unigenes involved in salt stress response. These differentially expressed unigenes were assigned to several metabolic pathways, including plant hormone signal transduction, RNA transporter, protein processing in endoplasmic reticulum and plant-pathogen interaction, which constructed the complex regulatory network to maintain osmotic and intracellular ion homeostasis. Quantitative real-time polymerase chain reaction was used to confirm the expression patterns of 20 unigenes. The results establish the foundation for the genetic basis of salt tolerance in P. tomentosa, which in turn accelerates Paulownia breeding and expands available arable land.

  4. Changes in Transcript Related to Osmosis and Intracellular Ion Homeostasis in Paulownia tomentosa under Salt Stress.

    Science.gov (United States)

    Fan, Guoqiang; Wang, Limin; Deng, Minjie; Zhao, Zhenli; Dong, Yanpeng; Zhang, Xiaoshen; Li, Yongsheng

    2016-01-01

    Paulownia tomentosa is an important economic and greening tree species that is cultivated widely, including salt environment. Our previous studies indicated its autotetraploid induced by colchicine showed better stress tolerance, but the underlying molecular mechanism related to ploidy and salt stress is still unclear. To investigate this issue, physiological measurements and transcriptome profiling of diploid and autotetraploid plants untreated and treated with NaCl were performed. Through the comparisons among four accessions, for one thing, we found different physiological changes between diploid and autotetraploid P. tomentosa; for another, and we detected many differentially expressed unigenes involved in salt stress response. These differentially expressed unigenes were assigned to several metabolic pathways, including "plant hormone signal transduction," "RNA transporter," "protein processing in endoplasmic reticulum," and "plant-pathogen interaction," which constructed the complex regulatory network to maintain osmotic and intracellular ion homeostasis. Quantitative real-time polymerase chain reaction was used to confirm the expression patterns of 20 unigenes. The results establish the foundation for the genetic basis of salt tolerance in P. tomentosa, which in turn accelerates Paulownia breeding and expands available arable land.

  5. Comprehensive theoretical analysis and experimental exploration of ultrafast microchip-based high-field asymmetric ion mobility spectrometry (FAIMS) technique.

    Science.gov (United States)

    Li, Lingfeng; Wang, Yonghuan; Chen, Chilai; Wang, Xiaozhi; Luo, Jikui

    2015-06-01

    High-field asymmetric ion mobility spectrometry (FAIMS) has become an efficient technique for separation and characterization of gas-phase ions at ambient pressure, which utilizes the mobility differences of ions at high and low fields. Micro FAIMS devices made by micro-electromechanical system technology have small gaps of the channels, high electric field and good installation precision, as thus they have received great attentions. However, the disadvantage of relatively low resolution limits their applications in some areas. In this study, theoretical analysis and experimental exploration were carried out to overcome the disadvantage. Multiple scans, characteristic decline curves of ion transmission and pattern recognitions were proposed to improve the performance of the microchip-based FAIMS. The results showed that although micro FAIMS instruments as a standalone chemical analyzer suffer from low resolution, by using one or more of the methods proposed, they can identify chemicals precisely and provide quantitative analysis with low detection limit in some applications. Copyright © 2015 John Wiley & Sons, Ltd.

  6. Characteristics and quantitative of negative ion in salt aqueous solution by Raman spectroscopy at -170℃

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    The results from Raman spectroscopy analysis of salt aqueous solutions at -170℃ demonstrate that for those clearly sharp iron peaks whose Raman wavenumber is close to each other such as and , their original shape could be restorable by the stripping technique, and that ice's sharp characteristic peak (3090-3109 cm-1) is steady, while the spectrum band of the complex compound (nCl--[H+-OH-]n) chlorine ion combined chemically with water molecule is 3401-3413 cm-1. On the other hand, the research shows that the higher the negative iron concentration, the stronger its Raman characteristic peak intensity and the smaller the ice's. Based on the number of data and theoretical work, the strong correlation of the molar concentration of negative ion with the band area ratio is built up. Moreover, the developed Raman method is successfully used in the component analysis of the field fluid inclusions from Silurian sandstone in Tarim basin.

  7. Interaction of the model alkyltrimethylammonium ions with alkali halide salts: an explicit water molecular dynamics study

    Directory of Open Access Journals (Sweden)

    M. Druchok

    2013-01-01

    Full Text Available We present an explicit water molecular dynamics simulation of dilute solutions of model alkyltrimethylammonium surfactant ions (number of methylene groups in the tail is 3, 5, 8, 10, and 12 in mixture with NaF, NaCl, NaBr, and NaI salts, respectively. The SPC/E model is used to describe water molecules. Results of the simulation at 298 K are presented in form of the radial distribution functions between nitrogen and carbon atoms of CH2 groups on the alkyltrimethylammonium ion, and the counterion species in the solution. The running coordination numbers between carbon atoms of surfactants and counterions are also calculated. We show that I- counterion exhibits the highest, and F- the lowest affinity to "bind" to the model surfactants. The results are discussed in view of the available experimental and simulation data for this and similar solutions.

  8. Spin Frustration in an Organic Radical Ion Salt Based on a Kagome-Coupled Chain Structure.

    Science.gov (United States)

    Postulka, Lars; Winter, Stephen M; Mihailov, Adam G; Mailman, Aaron; Assoud, Abdeljalil; Robertson, Craig M; Wolf, Bernd; Lang, Michael; Oakley, Richard T

    2016-08-31

    Electro-oxidation of the quinoidal bisdithiazole BT in dichloroethane in the presence of [Bu4N][GaBr4] affords the 1:1 radical ion salt [BT][GaBr4], crystals of which belong to the trigonal space group P3. The packing pattern of the radical cations provides a rare example of an organic kagome basket structure, with S = 1/2 radical ion chains located at the triangular corners of a trihexagonal lattice. Magnetic measurements over a wide temperature range from 30 mK to 300 K suggest strongly frustrated AFM interactions on the scale of J/kb ∼ 30 K, but reveal no anomalies that would be associated with magnetic order. These observations are discussed in terms of the symmetry allowed magnetic interactions within and between the frustrated layers.

  9. High-field asymmetric waveform ion mobility spectrometry with solvent vapor addition: a potential greener bioanalytical technique.

    Science.gov (United States)

    Tsai, Chia-Wei; Yost, Richard A; Garrett, Timothy J

    2012-06-01

    Green chemistry is a way to avoid threats to human health and the environment in chemical processes, including analytical methodology. According to the 12 principles provided by ACS Green Chemistry Institute, first described by Anastas and Warner, prevention of waste generation should be first considered as an alternative to ways of treating waste. Therefore, analytical techniques that may reduce solvent waste are of great interest towards greener analysis. High-field asymmetric waveform ion mobility spectrometry (FAIMS) utilizes electrical fields to achieve separation, post an ionization source, and could provide an alternative method for separation and reduce solvent use in comparison with traditional HPLC methodologies. In this article, the operational principles and developments of FAIMS will be discussed, including the advantages of adding solvent vapor to the carrier gas. In addition, applications and challenges of implementing FAIMS technology will also be discussed.

  10. Charged patchy particle models in explicit salt: Ion distributions, electrostatic potentials, and effective interactions

    Energy Technology Data Exchange (ETDEWEB)

    Yigit, Cemil; Dzubiella, Joachim, E-mail: joachim.dzubiella@helmholtz-berlin.de [Soft Matter and Functional Materials, Helmholtz-Zentrum Berlin, 14109 Berlin (Germany); Helmholtz Virtual Institute “Multifunctional Biomaterials for Medicine,” 14513 Teltow (Germany); Institut für Physik, Humboldt-Universität zu Berlin, 12489 Berlin (Germany); Heyda, Jan [Department of Physical Chemistry, University of Chemistry and Technology, Prague, 166 28 Praha 6 (Czech Republic)

    2015-08-14

    We introduce a set of charged patchy particle models (CPPMs) in order to systematically study the influence of electrostatic charge patchiness and multipolarity on macromolecular interactions by means of implicit-solvent, explicit-ion Langevin dynamics simulations employing the Gromacs software. We consider well-defined zero-, one-, and two-patched spherical globules each of the same net charge and (nanometer) size which are composed of discrete atoms. The studied mono- and multipole moments of the CPPMs are comparable to those of globular proteins with similar size. We first characterize ion distributions and electrostatic potentials around a single CPPM. Although angle-resolved radial distribution functions reveal the expected local accumulation and depletion of counter- and co-ions around the patches, respectively, the orientation-averaged electrostatic potential shows only a small variation among the various CPPMs due to space charge cancellations. Furthermore, we study the orientation-averaged potential of mean force (PMF), the number of accumulated ions on the patches, as well as the CPPM orientations along the center-to-center distance of a pair of CPPMs. We compare the PMFs to the classical Derjaguin-Verwey-Landau-Overbeek theory and previously introduced orientation-averaged Debye-Hückel pair potentials including dipolar interactions. Our simulations confirm the adequacy of the theories in their respective regimes of validity, while low salt concentrations and large multipolar interactions remain a challenge for tractable theoretical descriptions.

  11. Influence of silicon on microdistribution of mineral ions in roots of salt-stressed barley as associated with salt tolerance in plants

    Institute of Scientific and Technical Information of China (English)

    LIANG; Yongchao(梁永超); DING; Ruixing(丁瑞兴)

    2002-01-01

    Two contrasting barley (Hordeum vulgare L.) cultivars: Kepin No.7 (salt sensitive), and Jian 4 (salt tolerant) were grown hydroponically to investigate the microdistribution of mineral ions in roots as affected by silicon (Si) with respect to salt tolerance. The experiment was undertaken consisting of two treatments with 3 replicates: (i) 120 mmol@L?1 NaCl alone (referred to as Si(NaCl+), (ii) 120 mmol@L?1 NaCl + 1.0 mmol@L?1 Si (as potassium silicate) (referred to as Si+NaCl+). Plant root tips were harvested for microanalysis using an energy dispersive X-ray microanalyzer (EDX) 30 d after transplanting. Higher Cl and Na X-ray peaks were recorded in the root epidermal, cortical and stelar cells of roots for the treatment Si(NaCl+ with the majorities of Na and Cl being accumulated in epidermal and cortical cells, while relatively low K peaks were observed regardless of the barley cultivars used. By contrast, considerably higher K peaks were detected in the epidermal, cortical and stelar cells of the roots for the treatment Si+NaCl+, but lower Cl and Na peaks were also observed for this treatment with both Na and Cl ions being evenly distributed in the epidermal, cortical and stelar cells. These findings directly support our previous finding, which showed that Si depressed the uptake of sodium but enhanced the uptake of potassium by salt-stressed barley. We believe that one of the possible mechanisms involved in Si-enhancement of salt tolerance in barley is attributed to the Si-induced changes in the uptake and microdistribution of mineral ions in plants.

  12. The influence of ion binding and ion specific potentials on the double layer pressure between charged bilayers at low salt concentrations

    Science.gov (United States)

    Bostrom, M.; Lima, E. R. A.; Tavares, F. W.; Ninham, B. W.

    2008-04-01

    Measurements of surface forces between double-chained cationic bilayers adsorbed onto molecularly smooth mica surfaces across different millimolar salt solutions have revealed a large degree of ion specificity [Pashley et al., J. Phys. Chem. 90, 1637 (1986)]. This has been interpreted in terms of highly specific anion binding to the adsorbed bilayers. We show here that inclusion in the double layer theory of nonspecific ion binding and ion specific nonelectrostatic potentials acting between ions and the two surfaces can account for the phenomenon. It also gives the right Hofmeister series for the double layer pressure.

  13. Spatial Variability of Salt Ions in Soils in Oasis of Delta of Weigan River-Kuqa River in Different Seasons

    Institute of Scientific and Technical Information of China (English)

    Yuanyuan XU; Tashpolat TIYIP; Fei ZHANG; Jun XIA; Guihong HAN; Mamat SAWUT

    2012-01-01

    Abstract [Objective] The aim was to research the spatial variability of salts' ions in soils of oases of Weigan River-Kuqa River to explore spatial correlation among soil ions and effects of seasonal changes on distribution of eight ions in soils. [Method] Based on soil salinizaiton, temporal and spatial distributions of eight ions in surface soils were researched and distribution maps were drawn with the help of classical statistics and geostatistics. [Result] All contents of salt ions were proved in consistent with normal distribution by K-S test, and variability of the ions changed with season, for example, variability of ions in soils in October was higher than that in April, which might be caused by little rainfall and high evaporation in October. It can be concluded from semivariance analysis that salt ions were all of high spatial autocorrelation. In addition, it can be concluded from spatial distribution that spatial structures of most ions are reasonable, except Ca2+ and Mg2' in soils collected in April of 2010 and Mg2+ in October of 2010, which were more suitable for linear model, and chloride-sulfate dominated in salinized soils in the researching area. [Conclusion] The research laid foundation for partition, improvement and use of salin- ized soils in delta of Weigan River-Kuqa River.

  14. Organometallics and quaternary ammonium salts affect calcium ion desorption from lecithin liposome membranes.

    Science.gov (United States)

    Kral, T E; Kuczera, J; Przestalski, S

    2001-01-01

    The objective of the present work was to compare the effects of groups of tin and lead organometallic compounds and their mixtures with amphiphilic quaternary ammonium salts (QAS) on the process of calcium ion desorption from lecithin liposome membranes, as dependent on the properties of the hydrophilic and hydrophobic parts of QAS. In the investigations the method of radioactive labels was applied. Synergism and antagonism in the action of both groups of compounds were found. The effectiveness of the cooperation depended more on chain length of QAS compounds than on the size and polarity of their hydrophobic parts. The most effective of all compounds studied was a the mixture of benzyldimethylammonium chloride in a mixture with tripropyltin. Since the rate of calcium desorption proved to be a good measure of efficacy of biologically active surfactants, it seems that the conclusions reached in this paper may be useful for choosing compounds which are able to decontaminate the environment polluted with heavy metals.

  15. Analysis of paralytic shellfish toxins using high-field asymmetric waveform ion mobility spectrometry with liquid chromatography-mass spectrometry.

    Science.gov (United States)

    Beach, Daniel G; Melanson, Jeremy E; Purves, Randy W

    2015-03-01

    The analysis of paralytic shellfish toxins (PSTs) by liquid chromatography-mass spectrometry remains a challenge because of their high polarity, large number of analogues and the complex matrix in which they occur. Here we investigate the potential utility of high-field asymmetric waveform ion mobility spectrometry (FAIMS) as a gas-phase ion separation tool for analysis of PSTs by mass spectrometry. We investigate the separation of PSTs using FAIMS with two divergent goals: using FAIMS as a primary separation tool for rapid screening by electrospray ionization (ESI)-FAIMS-MS or combined with LC in a multidimensional LC-ESI-FAIMS-MS separation. First, a survey of the parameters that affect the sensitivity and selectivity of PST analysis by FAIMS was carried out using ESI-FAIMS-MS. In particular, the use of acetonitrile as a gas additive in the carrier gas flow offered good separation of all PST epimeric pairs. A second set of FAIMS conditions was also identified, which focussed PSTs to a relatively narrow CV range allowing development of an LC-ESI-FAIMS-MS method for analysis of PST toxins in complex mussel tissue extracts. The quantitative capabilities of this method were evaluated by analysing a PST containing mussel tissue matrix material. Results compared favourably with analysis by an established LC-post-column oxidation-fluorescence method with recoveries ranging from 70 to 106%, although sensitivity was somewhat reduced. The current work represents the first successful separation of PST isomers using ion mobility and shows the promise of FAIMS as a tool for analysis of algal biotoxins in complex samples and outlines some critical requirements for its future improvement.

  16. Calculation of activities of ions in molten salts with potential application to the pyroprocessing of nuclear waste.

    Science.gov (United States)

    Salanne, Mathieu; Simon, Christian; Turq, Pierre; Madden, Paul A

    2008-01-31

    The ability to separate fission products by electrodeposition from molten salts depends, in part, on differences between the interactions of the different fission product cations with the ions present in the molten salt "solvent". These differences may be expressed as ratios of activity coefficients, which depend on the identity of the solvent and other factors. Here, we demonstrate the ability to calculate these activity coefficient ratios using molecular dynamics simulations with sufficient precision to guide the choice of suitable solvent systems in practical applications. We use polarizable ion interaction potentials which have previously been shown to give excellent agreement with structural, transport, and spectroscopic information of the molten salts, and the activity coefficients calculated in this work agree well with experimental data. The activity coefficients are shown to vary systematically with cation size for a set of trivalent cations.

  17. On-line method to study dynamics of ion adsorption from mixtures of salts in capacitive deionization

    NARCIS (Netherlands)

    Dykstra, J.E.; Dijkstra, J.; Wal, van der A.; Hamelers, H.V.M.; Porada, S.

    2016-01-01

    Capacitive Deionization (CDI) is a water desalination technology that adsorbs ions into two oppositely polarized porous carbon electrodes, under the action of an applied voltage. Here, we introduce a novel method to analyze the effluent concentration of multiple ionic species in mixtures of salt

  18. Primary amine/CSA ion pair: A powerful catalytic system for the asymmetric enamine catalysis

    KAUST Repository

    Liu, Chen

    2011-05-20

    A novel ion pair catalyst containing a chiral counteranion can be readily derived by simply mixing cinchona alkaloid-derived diamine with chiral camphorsulfonic acid (CSA). A mixture of 9-amino(9-deoxy)epi-quinine 8 and (-)-CSA was found to be the best catalyst with matching chirality, enabling the direct amination of α-branched aldehydes to proceed in quantitative yields and with nearly perfect enantioselectivities. A 0.5 mol % catalyst loading was sufficient to catalyze the reaction, and a gram scale enantioselective synthesis of biologically important α-methyl phenylglycine has been successfully demonstrated. © 2011 American Chemical Society.

  19. Detection of Potato Storage Disease via Gas Analysis: A Pilot Study Using Field Asymmetric Ion Mobility Spectrometry

    Directory of Open Access Journals (Sweden)

    Massimo Rutolo

    2014-08-01

    Full Text Available Soft rot is a commonly occurring potato tuber disease that each year causes substantial losses to the food industry. Here, we explore the possibility of early detection of the disease via gas/vapor analysis, in a laboratory environment, using a recent technology known as FAIMS (Field Asymmetric Ion Mobility Spectrometry. In this work, tubers were inoculated with a bacterium causing the infection, Pectobacterium carotovorum, and stored within set environmental conditions in order to manage disease progression. They were compared with controls stored in the same conditions. Three different inoculation time courses were employed in order to obtain diseased potatoes showing clear signs of advanced infection (for standard detection and diseased potatoes with no apparent evidence of infection (for early detection. A total of 156 samples were processed by PCA (Principal Component Analysis and k-means clustering. Results show a clear discrimination between controls and diseased potatoes for all experiments with no difference among observations from standard and early detection. Further analysis was carried out by means of a statistical model based on LDA (Linear Discriminant Analysis that showed a high classification accuracy of 92.1% on the test set, obtained via a LOOCV (leave-one out cross-validation.

  20. LITERATURE REVIEWS TO SUPPORT ION EXCHANGE TECHNOLOGY SELECTION FOR MODULAR SALT PROCESSING

    Energy Technology Data Exchange (ETDEWEB)

    King, W

    2007-11-30

    This report summarizes the results of literature reviews conducted to support the selection of a cesium removal technology for application in a small column ion exchange (SCIX) unit supported within a high level waste tank. SCIX is being considered as a technology for the treatment of radioactive salt solutions in order to accelerate closure of waste tanks at the Savannah River Site (SRS) as part of the Modular Salt Processing (MSP) technology development program. Two ion exchange materials, spherical Resorcinol-Formaldehyde (RF) and engineered Crystalline Silicotitanate (CST), are being considered for use within the SCIX unit. Both ion exchange materials have been studied extensively and are known to have high affinities for cesium ions in caustic tank waste supernates. RF is an elutable organic resin and CST is a non-elutable inorganic material. Waste treatment processes developed for the two technologies will differ with regard to solutions processed, secondary waste streams generated, optimum column size, and waste throughput. Pertinent references, anticipated processing sequences for utilization in waste treatment, gaps in the available data, and technical comparisons will be provided for the two ion exchange materials to assist in technology selection for SCIX. The engineered, granular form of CST (UOP IE-911) was the baseline ion exchange material used for the initial development and design of the SRS SCIX process (McCabe, 2005). To date, in-tank SCIX has not been implemented for treatment of radioactive waste solutions at SRS. Since initial development and consideration of SCIX for SRS waste treatment an alternative technology has been developed as part of the River Protection Project Waste Treatment Plant (RPP-WTP) Research and Technology program (Thorson, 2006). Spherical RF resin is the baseline media for cesium removal in the RPP-WTP, which was designed for the treatment of radioactive waste supernates and is currently under construction in Hanford, WA

  1. Effects of salt stress on ion balance and nitrogen metabolism of old and young leaves in rice (Oryza sativa L.

    Directory of Open Access Journals (Sweden)

    Wang Huan

    2012-10-01

    Full Text Available Abstract Background It is well known that salt stress has different effects on old and young tissues. However, it remains largely unexplored whether old and young tissues have different regulatory mechanism during adaptation of plants to salt stress. The aim of this study was to investigate whether salt stress has different effects on the ion balance and nitrogen metabolism in the old and young leaves of rice, and to compare functions of both organs in rice salt tolerance. Results Rice protected young leaves from ion harm via the large accumulation of Na+ and Cl− in old leaves. The up-regulation of OsHKT1;1, OsHAK10 and OsHAK16 might contribute to accumulation of Na+ in old leaves under salt stress. In addition, lower expression of OsHKT1;5 and OsSOS1 in old leaves may decrease frequency of retrieving Na+ from old leaf cells. Under salt stress, old leaves showed higher concentration of NO3− content than young leaves. Up-regulation of OsNRT1;2, a gene coding nitrate transporter, might contribute to the accumulation of NO3− in the old leaves of salt stressed-rice. Salt stress clearly up-regulated the expression of OsGDH2 and OsGDH3 in old leaves, while strongly down-regulated expression of OsGS2 and OsFd-GOGAT in old leaves. Conclusions The down-regulation of OsGS2 and OsFd-GOGAT in old leaves might be a harmful response to excesses of Na+ and Cl−. Under salt stress, rice might accumulate Na+ and Cl− to toxic levels in old leaves. This might influence photorespiration process, reduce NH4+ production from photorespiration, and immediately down-regulate the expression of OsGS2 and OsFd-GOGAT in old leaves of salt stressed rice. Excesses of Na+ and Cl− also might change the pathway of NH4+ assimilation in old leaves of salt stressed rice plants, weaken GOGAT/GS pathway and elevate GDH pathway.

  2. Asymmetric hydration structure around calcium ion restricted in micropores fabricated in activated carbons

    Science.gov (United States)

    Ohkubo, Takahiro; Kusudo, Tomoko; Kuroda, Yasushige

    2016-11-01

    The adsorbed phase and hydration structure of an aqueous solution of Ca(NO3)2 restricted in micropores fabricated in activated carbons (ACs) having different average pore widths (0.63 and 1.1 nm) were investigated with the analysis of adsorption isotherms and x-ray absorption fine structure (XAFS) spectra on Ca K-edge. The adsorbed density of Ca2+ per unit micropore volume in the narrower pore was higher than in the wider pore, while the adsorbed amount per unit mass of carbon with the narrower pore was half of the amount of ACs with the larger pore. On the other hand, variations in the bands assigned to double-electron (KM I) and 1s  →  3d excitations in XAFS spectra demonstrate the formation of a distorted hydration cluster around Ca2+ in the micropore, although the structural parameters of hydrated Ca2+ in the micropores were almost consistent with the bulk aqueous solution, as revealed by the analysis of extended XAFS (EXAFS) spectra. In contrast to the hydration structure of monovalent ions such as Rb+, which generally presents a dehydrated structure in smaller than 1 nm micropores in ACs, the present study clearly explains that the non-spherically-symmetric structure of hydrated Ca2+ restricted in carbon micropores whose sizes are around 1 nm is experimentally revealed where any dehydration phenomena from the first hydration shell around Ca2+ could not be observed.

  3. Combination of Metal Coordination Tetrahedra and Asymmetric Coordination Geometries of Sb(III) in the Organically Directed Chalcogenidometalates: Structural Diversity and Ion-exchange Properties.

    Science.gov (United States)

    Feng, Mei-Ling; Wang, Kai-Yao; Huang, Xiao-Ying

    2016-04-01

    Chalcogenidometalates exhibit rich and diverse structures and properties applicable to ion exchange, thermoelectrics, photocatalysis, nonlinear optics, and so on. This personal account summarizes our recent progress in constructing chalcogenidometalates by combining metal coordination tetrahedra and the asymmetric coordination geometries of Sb(3+) in the presence of organic species (typically organic amines and metal-organic amine complexes), which has been demonstrated as an effective strategy for synthesizing chalcogenidometalates with diversified structures and interesting properties. The linkage modes of asymmetric SbQn (n = 3, 4) geometries and group 13 (or 14) metal coordination tetrahedra are analyzed, and the secondary building units (SBUs), with different compositions and architectures, are clarified. The crucial role and function of organic species in the formation of chalcogenidometalates are explored, with an emphasis on their powerful structure-directing features. In particular, some chalcogenidometalates in this family exhibit excellent ion-exchange properties for Cs(+) and/or Sr(2+) ions; the factors affecting ion-exchange properties are discussed to understand the underlying ion-exchange mechanism.

  4. Titratable Macroions in Multivalent Electrolyte Solutions: Strong Coupling Dressed Ion Approach

    CERN Document Server

    Adzic, Natasa

    2016-01-01

    We present a theoretical description of the effect of polyvalent ions on the interaction between titratable macro-ions. The model system consists of two point-like macro-ions with dissociable sites, immersed in an asymmetric ionic mixture of monovalent and polyvalent salts. We formulate a {\\em dressed ion strong coupling theory}, based on the decomposition of the asymmetric ionic mixture into a weakly electrostatically coupled monovalent salt, and into polyvalent ions that are strongly electrostatically coupled to the titratable macro-ions. The charge of the macroions is not considered as fixed, but is allowed to respond to local bathing solution parameters (electrostatic potential, $pH$ of the solution, salt concentration) through a simple {\\em charge regulation} model. The approach presented, yielding an effective polyvalent-ion mediated interaction between charge-regulated macro-ions at various solution conditions, describes the strong coupling equivalent of the Kirkwood-Schumaker interaction.

  5. Ion Recognition Approach to Volume Reduction of Alkaline Tank Waste by Separation of Sodium Salts

    Energy Technology Data Exchange (ETDEWEB)

    Moyer, Bruce A.; Bonnesen, Peter V.; Custelcean, Radu; Delmau, Laetitia H.; Engle, Nancy L.; Kang, Hyun-Ah; Keever, Tamara J.; Marchand, Alan P.; Gadthula, Srinivas; Gore, Vinayak K.; Huang, Zilin; Sivappa, Rasapalli; Tirunahari, Pavan K.; Levitskaia, Tatiana G.; Lumetta, Gregg J.

    2005-09-26

    The purpose of this research involving collaboration between Oak Ridge National Laboratory (ORNL) and Pacific Northwest National Laboratory (PNNL) is to explore new approaches to the separation of sodium hydroxide, sodium nitrate, and other sodium salts from high-level alkaline tank waste. The principal potential benefit is a major reduction in disposed waste volume, obviating the building of expensive new waste tanks and reducing the costs of vitrification. Principles of ion recognition are being researched toward discovery of liquid-liquid extraction systems that selectively separate sodium hydroxide and sodium nitrate from other waste components. The successful concept of pseudo hydroxide extraction using fluorinated alcohols and phenols is being developed at ORNL and PNNL toward a greater understanding of the controlling equilibria, role of solvation, and of synergistic effects involving crown ethers. Synthesis efforts are being directed toward enhanced sodium binding by crown ethers, both neutral and proton-ionizable. Studies with real tank waste at PNNL will provide feedback toward solvent compositions that have promising properties.

  6. Solvents in salt electrolyte: Benefits and possible use as electrolyte for lithium-ion battery

    Energy Technology Data Exchange (ETDEWEB)

    Taggougui, M.; Carre, B.; Lemordant, D. [Laboratoire de Chimie-physique des Interfaces et des Milieux Electrolytiques (EA2098), Universite de Tours, Faculte des Sciences et Techniques, Parc de Grandmont, F 37200 Tours (France); Diaw, M. [Universite Cheikh Anta Diop, Dakar (Senegal); Willmann, P. [CNES, 18 Avenue E. Belin, 31055 Toulouse Cedex (France)

    2008-07-01

    An EC/DEC [40:60% (v/v)] solvent mixture has been added in various amounts to the ionic liquid (IL) hexyltrimethylammonium bis(trifluoromethylsulfonyl)imide (N{sub 1116}-NTf{sub 2}) in the presence of LiNTf{sub 2} (lithium bis(trifluoromethylsulfonyl)imide) as lithium salt for possible use as electrolytes in lithium-ion batteries. These electrolytes exhibit a larger thermal stability than the reference electrolyte EC/DEC [40:60] + LiNTf{sub 2} 1 M when the percentage of the IL exceeds 30% (v/v). All studied electrolytes are glass forming ones with an ideal glass transition temperature of ca. -85 C({+-}5 C), which has been determined by application of the VTF theory to conductivity and viscosity measurements and confirmed by DSC (T{sub g} = -90 {+-} 5 C). An electrochemical window of about 5 V versus Li/Li{sup +} was measured at a glassy carbon electrode. The cycling ability of the optimized electrolyte N{sub 1116}-NTf{sub 2}/EC:DEC (40/60% (v/v)) + 1 M LiNTf{sub 2} has been investigated at a titanate oxide (Li{sub 4}Ti{sub 5}O{sub 12}) and a cobalt oxide (Li{sub x}CoO{sub 2}) electrodes. Cycling the positive and the negative electrodes was conducted successfully with a high capacity and without any significant fading. (author)

  7. Simultaneous removal of organic matter and salt ions from saline wastewater in bioelectrochemical systems

    KAUST Repository

    Kim, Younggy

    2013-01-01

    A new bioelectrochemical system is proposed for simultaneous removal of salinity and organic matter. In this process, exoelectrogenic microorganisms oxidize organic matter and transfer electrons to the anode, hydrogen is evolved at the cathode by supplying additional voltage, and salt is removed from the wastewater due to the electric potential generated and the use of two ion-exchange membranes. Salinity removal (initial conductivity ~40mS/cm) increased from 21 to 84% by increasing the substrate (sodium acetate) from 2 to 8g/L. A total of 72-94% of the chemical oxygen demand was degraded in the anode and cathode chambers, with 1-4% left in the anode chamber and the balance lost through the anion-exchange membrane into the concentrate waste chamber. The maximum hydrogen production rate was 3.6m3-H2/m3-electrolyte per day at an applied potential of 1.2V. The Coulombic efficiency was ~100%, while the cathode recovery varied from 57 to 100%, depending on the extent of methanogenesis. Exoelectrogenic microbes generated high current densities (7.8mA/cm2) at ≤36g/L of total dissolved solids, but >41g/L eliminated current. These results provide a new method for achieving simultaneous removal of salinity and organic matter from a saline wastewater with H2 production. © 2012 Elsevier B.V.

  8. Asymmetric cation-binding catalysis

    DEFF Research Database (Denmark)

    Oliveira, Maria Teresa; Lee, Jiwoong

    2017-01-01

    and KCN, are selectively bound to the catalyst, providing exceptionally high enantioselectivities for kinetic resolutions, elimination reactions (fluoride base), and Strecker synthesis (cyanide nucleophile). Asymmetric cation-binding catalysis was recently expanded to silicon-based reagents, enabling...... solvents, thus increasing their applicability in synthesis. The expansion of this concept to chiral polyethers led to the emergence of asymmetric cation-binding catalysis, where chiral counter anions are generated from metal salts, particularly using BINOL-based polyethers. Alkali metal salts, namely KF...

  9. Actions of Angeli's salt, a nitroxyl (HNO) donor, on ion transport across mucosa-submucosa preparations from rat distal colon.

    Science.gov (United States)

    Pouokam, Ervice; Bell, Anna; Diener, Martin

    2013-09-05

    The aim of this study was to investigate whether nitroxyl (HNO), a redox variant of the radical gasotransmitter nitric oxide (NO) with therapeutically promising properties, affects colonic ion transport. Changes in short-circuit current (Isc) induced by the HNO donor Angeli's salt were recorded in Ussing chambers. Cytosolic Ca(2+) concentration was measured with fura-2. The nitroxyl donor induced a concentration-dependent increase in Isc across rat distal colon which was due to a stimulation of chloride secretion. The secretion induced by Angeli's salt (5×10(-4)mol/l) was not altered by the NO scavenger 2-(4-carboxyphenyl)-4,5-dihydro-4,4,5,5-tetramethyl-1H-imidazolyl-1-oxy-3-oxide (carboxy-PTIO), but was abolished by the HNO scavenger l-cysteine. The response was not dependent on the activity of soluble guanylate cyclase or enteric neurons, but was inhibited by indomethacin. Experiments with apically permeabilized epithelia revealed the activation of basolateral K(+) channels and a stimulation of the current carried by the basolateral Na(+)-K(+)-pump by Angeli's salt. The secretion induced by Angeli's salt was reduced in the absence of extracellular Ca(2+). A prominent increase in the cytosolic Ca(2+) concentration was evoked by Angeli's salt predominantly in subepithelial cells within the submucosa, which had the same dependence on extracellular Ca(2+) as the Angeli's salt-induced Cl(-) secretion. Consequently, Angeli's salt induces a soluble guanylate cyclase-independent, Ca(2+)-dependent Cl(-) secretion via activation of the Na(+)-K(+)-ATPase and of basolateral K(+) channels. Cyclooxygenase metabolites produced within the submucosa seem to be involved in this response.

  10. Hydroxy double salts loaded with bioactive ions: Synthesis, intercalation mechanisms, and functional performance

    Energy Technology Data Exchange (ETDEWEB)

    Kaassis, Abdessamad Y.A. [UCL School of Pharmacy, University College London, 29-39 Brunswick Square, London WC1N 1AX (United Kingdom); Xu, Si-Min; Guan, Shanyue; Evans, David G. [State Key Laboratory of Chemical Resource Engineering, Beijing University of Chemical Technology, Beijing 100029 (China); Wei, Min, E-mail: weimin@mail.buct.edu.cn [State Key Laboratory of Chemical Resource Engineering, Beijing University of Chemical Technology, Beijing 100029 (China); Williams, Gareth R., E-mail: g.williams@ucl.ac.uk [UCL School of Pharmacy, University College London, 29-39 Brunswick Square, London WC1N 1AX (United Kingdom)

    2016-06-15

    The intercalation of the anions of diclofenac (Dic), naproxen (Nap), and valproic acid (Val) into three hydroxy double salts (HDSs) has been explored in this work. Experiments were performed with [Co{sub 1.2}Zn{sub 3.8}(OH){sub 8}](NO{sub 3}){sub 2}·2H{sub 2}O (CoZn-NO{sub 3}), [Ni{sub 2}Zn{sub 3}(OH){sub 8}](NO{sub 3}){sub 2}·2H{sub 2}O (NiZn-NO{sub 3}) and [Zn{sub 5}(OH){sub 8}](NO{sub 3}){sub 2}·2H{sub 2}O (Zn-NO{sub 3}). It proved possible to intercalate diclofenac and naproxen into all three HDSs. In contrast, Val could be intercalated into CoZn-NO{sub 3} but when it was reacted with Zn-NO{sub 3} the HDS structure was destroyed, and the product comprised ZnO. Successful intercalation was verified by X-ray diffraction, IR spectroscopy, and elemental microanalysis. Molecular dynamics simulations showed the Dic and Nap ions to arrange themselves in an “X” shape in the interlayer space, forming a bilayer. Val was found to adopt a position with its aliphatic groups parallel to the HDS layer, again in a bilayer. In situ time resolved X-ray diffraction experiments revealed that intercalation of Dic and Nap into CoZn-NO{sub 3} and Zn-NO{sub 3} is mechanistically complex, with a number of intermediate phases observed. In contrast, the intercalation of all three guests into NiZn-NO{sub 3} and of Val into CoZn-NO{sub 3} are simple one step reactions proceeding directly from the starting material to the product. The HDS-drug composites were found to have sustained release profiles. - Graphical abstract: Seven new drug intercalates of hydroxy double salts (HDSs) have been prepared and characterised. The intercalation mechanisms have been explored, and the drug release properties of the HDS/drug composites quantified. Display Omitted.

  11. Influences of nitrification inhibitor 3,4-dimethyl pyrazole phosphate on nitrogen and soil salt-ion leaching

    Institute of Scientific and Technical Information of China (English)

    YU Qiaogang; YE Xuezhu; CHEN Yingxu; ZHANG Zhijian; TIAN Guangming

    2008-01-01

    An undisturbed heavy clay soil column experiment was conducted to examine the influence of the new nitrification inhibitor,3,4-dimethylpyrazole phosphate (DMPP),on nitrogen and soil salt-ion leaching.Regular urea was selected as the nitrogen source in the soil.The results showed that the cumulative leaching losses of soil nitrate-N under the treatment of urea with DMPP were from 57.5% to 63.3% lower than those of the treatment of urea without DMPP.The use of nitrification inhibitors as nitrate leaching retardants may be a proposal in regulations to prevent groundwater contaminant.However,there were no great difference between urea and urea with DMPP treatments on ammonium-N leaching.Moreover,the soil salt-ion leaching losses of Ca2+,Mg2+,K+,and Na+ were reduced from 26.6% to 28.8%,21.3% to 27.8%,33.3% to 35.5%,and 21.7% to 32.1%,respectively.So,the leaching losses of soil salt-ion were declined for nitrification inhibitor DMPP addition,being beneficial to shallow groundwater protection and growth of crop.These results indicated the possibility of ammonium or ammonium producing compounds using nitrification inhibitor DMPP to control the nitrate and nutrient cation leaching losses,minimizing the risk of nitrate pollution in shallow groundwater.

  12. Influences of nitrification inhibitor 3,4-dimethyl pyrazole phosphate on nitrogen and soil salt-ion leaching.

    Science.gov (United States)

    Yu, Qiaogang; Ye, Xuezhu; Chen, Yingxu; Zhang, Zhijian; Tian, Guangming

    2008-01-01

    An undisturbed heavy clay soil column experiment was conducted to examine the influence of the new nitrification inhibitor, 3,4-dimethylpyrazole phosphate (DMPP), on nitrogen and soil salt-ion leaching. Regular urea was selected as the nitrogen source in the soil. The results showed that the cumulative leaching losses of soil nitrate-N under the treatment of urea with DMPP were from 57.5% to 63.3% lower than those of the treatment of urea without DMPP. The use of nitrification inhibitors as nitrate leaching retardants may be a proposal in regulations to prevent groundwater contaminant. However, there were no great difference between urea and urea with DMPP treatments on ammonium-N leaching. Moreover, the soil salt-ion leaching losses of Ca2+, Mg2+, K+, and Na+ were reduced from 26.6% to 28.8%, 21.3% to 27.8%, 33.3% to 35.5%, and 21.7% to 32.1%, respectively. So, the leaching losses of soil salt-ion were declined for nitrification inhibitor DMPP addition, being beneficial to shallow groundwater protection and growth of crop. These results indicated the possibility of ammonium or ammonium producing compounds using nitrification inhibitor DMPP to control the nitrate and nutrient cation leaching losses, minimizing the risk of nitrate pollution in shallow groundwater.

  13. Analysis of trace inorganic anions in weak acid salts by single pump cycling-column-switching ion chromatography.

    Science.gov (United States)

    Huang, Zhongping; Ni, Chengzhu; Zhu, Zhuyi; Pan, Zaifa; Wang, Lili; Zhu, Yan

    2015-05-01

    The application of ion chromatography with the single pump cycling-column-switching technique was described for the analysis of trace inorganic anions in weak acid salts within a single run. Due to the hydrogen ions provided by an anion suppressor electrolyzing water, weak acid anions could be transformed into weak acids, existing as molecules, after passing through the suppressor. Therefore, an anion suppressor and ion-exclusion column were adopted to achieve on-line matrix elimination of weak acid anions with high concentration for the analysis of trace inorganic anions in weak acid salts. A series of standard solutions consisting of target anions of various concentrations from 0.005 to 10 mg/L were analyzed, with correlation coefficients r ≥ 0.9990. The limits of detection were in the range of 0.67 to 1.51 μg/L, based on the signal-to-noise ratio of 3 and a 25 μL injection volume. Relative standard deviations for retention time, peak area, and peak height were all less than 2.01%. A spiking study was performed with satisfactory recoveries between 90.3 and 104.4% for all anions. The chromatographic system was successfully applied to the analysis of trace inorganic anions in five weak acid salts.

  14. Hydroxy double salts loaded with bioactive ions: Synthesis, intercalation mechanisms, and functional performance

    Science.gov (United States)

    Y. A. Kaassis, Abdessamad; Xu, Si-Min; Guan, Shanyue; Evans, David G.; Wei, Min; Williams, Gareth R.

    2016-06-01

    The intercalation of the anions of diclofenac (Dic), naproxen (Nap), and valproic acid (Val) into three hydroxy double salts (HDSs) has been explored in this work. Experiments were performed with [Co1.2Zn3.8(OH)8](NO3)2·2H2O (CoZn-NO3), [Ni2Zn3(OH)8](NO3)2·2H2O (NiZn-NO3) and [Zn5(OH)8](NO3)2·2H2O (Zn-NO3). It proved possible to intercalate diclofenac and naproxen into all three HDSs. In contrast, Val could be intercalated into CoZn-NO3 but when it was reacted with Zn-NO3 the HDS structure was destroyed, and the product comprised ZnO. Successful intercalation was verified by X-ray diffraction, IR spectroscopy, and elemental microanalysis. Molecular dynamics simulations showed the Dic and Nap ions to arrange themselves in an "X" shape in the interlayer space, forming a bilayer. Val was found to adopt a position with its aliphatic groups parallel to the HDS layer, again in a bilayer. In situ time resolved X-ray diffraction experiments revealed that intercalation of Dic and Nap into CoZn-NO3 and Zn-NO3 is mechanistically complex, with a number of intermediate phases observed. In contrast, the intercalation of all three guests into NiZn-NO3 and of Val into CoZn-NO3 are simple one step reactions proceeding directly from the starting material to the product. The HDS-drug composites were found to have sustained release profiles.

  15. Evaluation of ion mobility spectroscopy for determining charge-solvated versus salt-bridge structures of protonated trimers.

    Science.gov (United States)

    Wong, Richard L; Williams, Evan R; Counterman, Anne E; Clemmer, David E

    2005-07-01

    The cross sections of five different protonated trimers consisting of two base molecules and trifluoroacetic acid were measured by using ion mobility spectrometry. The gas-phase basicities of these five base molecules span an 8-kcal/mol range. These cross sections are compared with those determined from candidate low-energy salt-bridge and charge-solvated structures identified by using molecular mechanics calculations using three different force fields: AMBER*, MMFF, and CHARMm. With AMBER*, the charge-solvated structures are all globular and the salt-bridge structures are all linear, whereas with CHARMm, these two forms of the protonated trimers can adopt either shape. Globular structures have smaller cross sections than linear structures. Conclusions about the structure of these protonated trimers are highly dependent on the force field used to generate low-energy candidate structures. With AMBER*, all of the trimers are consistent with salt-bridge structures, whereas with MMFF the measured cross sections are more consistent with charge-solvated structures, although the assignments are ambiguous for two of the protonated trimers. Conclusions based on structures generated by using CHARMm suggest a change in structure from charge-solvated to salt-bridge structures with increasing gas-phase basicity of the constituent bases, a result that is most consistent with structural conclusions based on blackbody infrared radiative dissociation experiments for these protonated trimers and theoretical calculations on the uncharged base-acid pairs.

  16. Impact of Solid Electrolyte Interphase lithium salts on cycling ability of Li-ion battery: Beneficial effect of glymes additives

    Science.gov (United States)

    Chrétien, Fabien; Jones, Jennifer; Damas, Christine; Lemordant, Daniel; Willmann, Patrick; Anouti, Mérièm

    2014-02-01

    The Solid Electrolyte Interphase (SEI), formed during the first cycles of life in lithium-ion batteries, contains a variety of lithium salts, with direct effect on the aging performance of the battery. In this work, we investigate the impact of addition of SEI lithium salts (LiF, Li2CO3, LiOH, Li2O, LiOCH3 and LiOC2H5) in the electrolyte on the cycling ability of graphite and LiNi1/3Mn1/3Co1/3O2 (NMC) electrodes. Results show that NMC is more sensitive to salt addition than graphite material. Furthermore, results demonstrate that both LiOH and Li2O have a negative effect on the SEI formation. Conversely, Li2CO3, LiOCH3 and LiOC2H5 are beneficial and promote the formation of a polymeric coating on the SEI. Finally, the impact of the presence of LiF on the SEI depends mainly on its concentration. The effect of the presence of additives capable of complexing lithium salts such as the glyme series, CH3O[CH2CH2O]nCH3 (Gn, with n = 2, 3 or 4), is investigated by cyclic voltammetry, galvanostatic charge-discharge tests and electrochemical impedance spectroscopy (EIS). Results show that the glymes chain length is a determining factor in their complexation mechanism, which depends on both the nature and the concentration of the lithium salt.

  17. OBTAINING OF THE MG2+ FORM OF THE ZEOLITE 4A WITH ION EXCHANGE OF MAGNESIUM SALTS

    Directory of Open Access Journals (Sweden)

    Blagica Cekova

    2016-01-01

    Full Text Available Zeolites are sodium alumino silicates which in in their composition contain zeolite water. They have a three-dimensional structure. Spatial structure defined by a strictly defined geometry of pores and cavities. For ionic еchange is used magnesium salt (MgCl2*6H2O whose aqueous solutions were with the following concentrations (MgCl2*6H2O = 2,5; 3.5; 4,5 mol / dm3 , and other parameters of the ion exchange: time t = 20, 30, 40 and temperature of 298 and 330 K. Ionian capacity is calculated as mmgMgO / 1g zeolite.

  18. The 2-D Ion Chromatography Development and Application: Determination of Sulfate in Formation Water at Pre-Salt Region

    Science.gov (United States)

    Tonietto, G. B.; Godoy, J. M.; Almeida, A. C.; Mendes, D.; Soluri, D.; Leite, R. S.; Chalom, M. Y.

    2015-12-01

    Formation water is the naturally-occurring water which is contained within the geological formation itself. The quantity and quality of the formation water can both be problematic. Over time, the water volume should decrease as the gas volumes increase. Formation water has been found to contain high levels of Cl, As, Fe, Ba, Mn, PAHs and may even contain naturally occurring radioactive materials. Chlorides in some cases have been found to be in excess of four-five times the level of concentrations found in the ocean. Within the management of well operation, there is sulfate between the analytes of greatest importance due to the potential for hydrogen sulphide formation and consequent corrosion of pipelines. As the concentration of sulfate in these waters can be less than n times that of chloride, a quantitative determination, using the technique of ion chromatography, constitutes an analytical challenge. This work aimed to develop and validate a method for the determination of sulphate ions in hyper-saline waters coming from the oil wells of the pre-salt, using 2D IC. In 2D IC the first column can be understood as a separating column, in which the species with retention times outside a preset range are discarded, while those belonging to this range are retained in a pre-concentrator column to further injecting a second column, the second dimension in which occurs the separation and quantification of the analytes of interest. As the chloride ions have a retention time lower than that of sulfate, a method was developed a for determining sulfate in very low range (mg L-1) by 2D IC, applicable to hypersaline waters, wherein the first dimension is used to the elimination of the matrix, ie, chloride ions, and the second dimension utilized in determining sulfate. For sulphate in a concentration range from 1.00 mg L-1 was obtained an accuracy of 1.0%. The accuracy of the method was tested by the standard addition method different samples of formation water in the pre-salt

  19. Strain evolution in Si substrate due to implantation of MeV ion observed by extremely asymmetric x-ray diffraction

    Science.gov (United States)

    Emoto, T.; Ghatak, J.; Satyam, P. V.; Akimoto, K.

    2009-08-01

    We studied the strain introduced in a Si(111) substrate due to MeV ion implantation using extremely asymmetric x-ray diffraction and measured the rocking curves of asymmetrical 113 diffraction for the Si substrates implanted with a 1.5 MeV Au2+ ion at fluence values of 1×1013, 5×1013, and 1×1014/cm2. The measured curves consisted of a bulk peak and accompanying subpeak with an interference fringe. The positional relationship of the bulk peak to the subpeak and the intensity variation of those peaks with respect to the wavelengths of the x rays indicated that crystal lattices near the surface were strained; the lattice spacing of surface normal (111) planes near the surface was larger than that of the bulk. Detailed strain profiles along the depth direction were successfully estimated using a curve-fitting method based on Darwin's dynamical diffraction theory. Comparing the shapes of resultant strain profiles, we found that a strain evolution rapidly occurred within a depth of ˜300 nm at fluence values between 1×1013 and 5×1013/cm2. This indicates that formation of the complex defects progressed near the surface when the fluence value went beyond a critical value between 1×1013 and 5×1013/cm2 and the defects brought a large strain to the substrate.

  20. Elucidating the structures and cooperative binding mechanism of cesium salts to the multitopic ion-pair receptor through density functional theory calculations.

    Science.gov (United States)

    Sadhu, Biswajit; Sundararajan, Mahesh; Velmurugan, Gunasekaran; Venuvanalingam, Ponnambalam

    2015-09-21

    Designing new and innovative receptors for the selective binding of radionuclides is central to nuclear waste management processes. Recently, a new multi-topic ion-pair receptor was reported which binds a variety of cesium salts. Due to the large size of the receptor, quantum chemical calculations on the full ion-pair receptors are restricted, thus the binding mechanisms are not well understood at the molecular level. We have assessed the binding strengths of various cesium salts to the recently synthesized multi-topic ion-pair receptor molecule using density functional theory based calculations. Our calculations predict that the binding of cesium salts to the receptor predominantly occurs via the cooperative binding mechanism. Cesium and the anion synergistically assist each other to bind favorably inside the receptor. Energy decomposition analysis on the ion-pair complexes shows that the Cs salts are bound to the receptor mainly through electrostatic interactions with small contribution from covalent interactions for large ionic radius anions. Further, QTAIM analysis characterizes the importance of different inter-molecular interactions between the ions and the receptor inside the ion-pair complexes. The role of the crystallographic solvent molecule contributes significantly by ~10 kcal mol(-1) to the overall binding affinities which is quite significant. Further, unlike the recent molecular mechanics (MM) calculations, our calculated binding affinity trends for various Cs ion-pair complexes (CsF, CsCl and CsNO3) are now in excellent agreement with the experimental binding affinity trends.

  1. Origin of Asymmetric Solvation Effects for Ions in Water and Organic Solvents Investigated Using Molecular Dynamics Simulations: The Swain Acity-Basity Scale Revisited.

    Science.gov (United States)

    Reif, Maria M; Hünenberger, Philippe H

    2016-08-25

    The asymmetric solvation of ions can be defined as the tendency of a solvent to preferentially solvate anions over cations or cations over anions, at identical ionic charge magnitudes and effective sizes. Taking water as a reference, these effects are quantified experimentally for many solvents by the relative acity (A) and basity (B) parameters of the Swain scale. The goal of the present study is to investigate the asymmetric solvation of ions using molecular dynamics simulations, and to connect the results to this empirical scale. To this purpose, the charging free energies of alkali and halide ions, and of their hypothetical oppositely charged counterparts, are calculated in a variety of solvents. In a first set of calculations, artificial solvent models are considered that present either a charge or a shape asymmetry at the molecular level. The solvation asymmetry, probed by the difference in charging free energy between the two oppositely charged ions, is found to encompass a term quadratic in the ion charge, related to the different solvation structures around the anion and cation, and a term linear in the ion charge, related to the solvation structure around the uncharged ion-sized cavity. For these simple solvent models, the two terms are systematically counteracting each other, and it is argued that only the quadratic term should be retained when comparing the results of simulations involving physical solvents to experimental data. In a second set of calculations, 16 physical solvents are considered. The theoretical estimates for the acity A are found to correlate very well with the Swain parameters, whereas the correlation for B is very poor. Based on this observation, the Swain scale is reformulated into a new scale involving an asymmetry parameter Σ, positive for acitic solvents and negative for basitic ones, and a polarity parameter Π. This revised scale has the same predictive power as the original scale, but it characterizes asymmetry in an

  2. Absorbance of UO{sub 2}{sup 2+} ion in NaCl-2CsCl molten salt

    Energy Technology Data Exchange (ETDEWEB)

    Sato, Fuminori; Tayama, Toshimitsu [Japan Nuclear Cycle Development Inst., Tokai Works, Tokai, Ibaraki (Japan); Nagai, Takayuki [Japan Nuclear Cycle Development Inst., Innovative Research Promotion Office, Tokai, Ibaraki (Japan)

    2003-06-01

    In Feasibility Studies (FS) for the commercialized fast breeder reactor (FBR) cycle system, the oxide electrowinning process is being developed by Japan Nuclear Cycle Development Institute (JNC). In the oxide electrowinning process, spent nuclear fuel is dissolved into molten salt and U and Pu are recovered as MOX by MOX-electrolysis. MOX-electrolysis has many requirements such as U/Pu ratio controls and separation from FP of U-Pu. Therefore, it is necessary to analyze the amounts of nuclear material (U and Pu) in the molten salt and control MOX-electrolysis based on this analysis result. This report considers the optical method as one candidate for process analysis technology. Absorbance of UO{sub 2}{sup 2+} ion, the basic data for optical analysis, was measured in NaCl-2CsCl molten salt. Although Khokhryakov reported on UO{sub 2}{sup 2+} absorbance using the Reflection-Absorption method no detailed report exists on the relation between absorbance and UO{sub 2}{sup 2+} concentration. Therefore, necessary spectral data for the process analysis technology were collected by the experiment. (author)

  3. Recovery of salts from ion-exchange regeneration streams by a coupled nanofiltration-membrane distillation process.

    Science.gov (United States)

    Jiříček, Tomáš; De Schepper, Wim; Lederer, Tomáš; Cauwenberg, Peter; Genné, Inge

    2015-01-01

    Ion-exchange tap water demineralization for process water preparation results in a saline regeneration wastewater (20-100 mS cm(-1)) that is increasingly problematic in view of discharge. A coupled nanofiltration-membrane distillation (NF-MD) process is evaluated for the recovery of water and sodium chloride from this wastewater. NF-MD treatment of mixed regeneration wastewater is compared to NF-MD treatment of separate anion- and cation-regenerate fractions. NF on mixed regeneration wastewater results in a higher flux (30 L m(-2) h(-1) at 7 bar) compared to NF on the separate fractions (6-9 L m(-2) h(-1) at 30 bar). NF permeate recovery is strongly limited by scaling (50% for separate and 60% for mixed, respectively). Physical signs of scaling were found during MD treatment of the NF permeates but did not result in flux decline for mixed regeneration wastewater. Final salt composition is expected to qualify as a road de-icing salt. NF-MD is an economically viable alternative compared to external disposal of wastewater for larger-scale installations (1.4 versus 2.5 euro m(-3) produced demineralized water for a 10 m3 regenerate per day plant). The cost benefits of water re-use and salt recuperation are small when compared to total treatment costs for mixed regenerate wastewater.

  4. Relation between Quick Clay Formation by Salt Leaching and Pore-water Ion Composition

    OpenAIRE

    安部, 宏; ヘ, パニー; 大坪, 政美; 東, 孝寛; 金山, 素平

    2013-01-01

    Several studies have reported that quick clay can be formed artificially by salt-leaching treatment on undisturbed Ariake clay. In the present study, however, artificial salt-leaching on the undisturbed clay taken from a site in Shiroishi-cho of Saga Prefecture failed to produce quick clay. To identify the cause, pore-water chemistry of the clay was assessed and the predominance of divalent cation in pore water was found to be responsible for the poor development of quick clay. Assuming that ...

  5. Fluorine-free electrolytes for all-solid sodium-ion batteries based on percyano-substituted organic salts

    Science.gov (United States)

    Bitner-Michalska, Anna; Nolis, Gene M.; Żukowska, Grażyna; Zalewska, Aldona; Poterała, Marcin; Trzeciak, Tomasz; Dranka, Maciej; Kalita, Michał; Jankowski, Piotr; Niedzicki, Leszek; Zachara, Janusz; Marcinek, Marek; Wieczorek, Władysław

    2017-01-01

    A new family of fluorine-free solid-polymer electrolytes, for use in sodium-ion battery applications, is presented. Three novel sodium salts withdiffuse negative charges: sodium pentacyanopropenide (NaPCPI), sodium 2,3,4,5-tetracyanopirolate (NaTCP) and sodium 2,4,5-tricyanoimidazolate (NaTIM) were designed andtested in a poly(ethylene oxide) (PEO) matrix as polymer electrolytes for anall-solid sodium-ion battery. Due to unique, non-covalent structural configurations of anions, improved ionic conductivities were observed. As an example, “liquid-like” high conductivities (>1 mS cm‑1) were obtained above 70 °C for solid-polymer electrolyte with a PEO to NaTCP molar ratio of 16:1. All presented salts showed high thermal stability and suitable windows of electrochemical stability between 3 and 5 V. These new anions open a new class of compounds with non-covalent structure for electrolytes system applications.

  6. Fluorine-free electrolytes for all-solid sodium-ion batteries based on percyano-substituted organic salts

    Science.gov (United States)

    Bitner-Michalska, Anna; Nolis, Gene M.; Żukowska, Grażyna; Zalewska, Aldona; Poterała, Marcin; Trzeciak, Tomasz; Dranka, Maciej; Kalita, Michał; Jankowski, Piotr; Niedzicki, Leszek; Zachara, Janusz; Marcinek, Marek; Wieczorek, Władysław

    2017-01-01

    A new family of fluorine-free solid-polymer electrolytes, for use in sodium-ion battery applications, is presented. Three novel sodium salts withdiffuse negative charges: sodium pentacyanopropenide (NaPCPI), sodium 2,3,4,5-tetracyanopirolate (NaTCP) and sodium 2,4,5-tricyanoimidazolate (NaTIM) were designed andtested in a poly(ethylene oxide) (PEO) matrix as polymer electrolytes for anall-solid sodium-ion battery. Due to unique, non-covalent structural configurations of anions, improved ionic conductivities were observed. As an example, “liquid-like” high conductivities (>1 mS cm−1) were obtained above 70 °C for solid-polymer electrolyte with a PEO to NaTCP molar ratio of 16:1. All presented salts showed high thermal stability and suitable windows of electrochemical stability between 3 and 5 V. These new anions open a new class of compounds with non-covalent structure for electrolytes system applications. PMID:28067301

  7. Syntheses and Application of All-lithium Salts of Heteropolyacid as Electrolyte of Lithium-ion Battery

    Institute of Scientific and Technical Information of China (English)

    CHEN Ya-guang; WANG Cun-guo; ZHANG Xi-yan; XIE De-min; WANG Rong-shun

    2004-01-01

    The all-lithium salts of heteropoly acid LixXM12O40(HPA-Li)(X=P, Si; M=Mo, W) were obtained via ion exchange and characterized by means of IR and UV spectroscopies, TG and elemental analyses. The conductivity of the electrolytic solution consisting of Li3PW12O40 and PC/DME mixing solvent(1/2.5, volume ratio) is up to 7.2×10-2 S/cm, being higher than that of LiClO4 as the electrolyte. The all-lithium salts were used as electrolytes in secondary lithium-ion batteries. The discharge capacity of the PAS/Li batteries with Li3PW12O40 electrolyte solutions reaches to 148 (mA*h)/g and the cyclic life is up to 380 times, much better than those of commercialized products with LiClO4 and LiAsF6 as electrolytes.

  8. Electro-membrane reactor for separation and in situ ion substitution of glutamic acid from its sodium salt

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, Mahendra; Tripathi, Bijay P. [Electro-Membrane Processes Division, Central Salt and Marine Chemicals Research Institute, Council of Scientific and Industrial Research (CSIR), G. B. Marg, Bhavnagar 364002, Gujarat (India); Shahi, Vinod K. [Electro-Membrane Processes Division, Central Salt and Marine Chemicals Research Institute, Council of Scientific and Industrial Research (CSIR), G. B. Marg, Bhavnagar 364002, Gujarat (India)], E-mail: vkshahi@csmcri.org

    2009-08-30

    An electro-membrane reactor with four compartments (EMR-4) (anolyte, catholyte and comp. 1 and 2) based on in-house-prepared cation- and anion-exchange membrane (CEM and AEM, respectively) was developed to achieve separation and recovery of glutamic acid (GAH) from its sodium salt by in situ ion substitution and acidification. The physicochemical and electrochemical properties of CEM and AEM were characterized and its suitability was assessed in operating environment. The separation of GA{sup -} from the mixture of nonionic organic compounds and further ion substitution was achieved by EMR-4. But the higher energy consumption (5.75 kWh/kg of GAH produced), low current efficiency (50.5%) and recovery of GAH (57.2%) in this process were main obstacles for the industrial exploration of the process. Latter, electro-membrane reactor with three compartments (EMR-3) (anolyte, catholyte and central compartment) was developed based on CEMs for only in situ ion substitution of GANa to achieve GAH, in which GA{sup -} was not allowed for electro-migration from its feed compartment. CE and recovery of GAH were close to 73% and 96% that indicate the suitability of the EMR-3 process for industrial application over the EMR-4. It was concluded that EMR-3 was efficient as compared to EMR-4 for separation and recovery of GAH from fermentation broth by in situ ion substitution in eco-friendly manner.

  9. Study of quantitative interactions of potato and corn starch granules with ions in diluted solutions of heavy metal salts.

    Science.gov (United States)

    Szymońska, Joanna; Molenda, Marcin; Wieczorek, Jerzy

    2015-12-10

    Interactions of potato and corn starch granules with ions in diluted solutions of silver, lead, copper or iron salts were investigated. It was shown experimentally that granules accumulated the cations in amounts depending on the granule structure and water content as well as a type of both metal and counter-ions present in solution. Potato starch retained almost three times more cations compared to corn starch what was proportional to the total phosphorous content in these starches. Quantity of milligrams of cations bound by 1g of starch was inversely correlated with the cation hydration. Ag(+), Pb(2+) and Cu(2+) were connected in stoichiometric amounts of moles to semicrystalline and amorphous parts of the granules. Fe(3+) ions were accumulated in higher than stoichiometric quantities mainly in granule amorphous regions. Metal ions penetrated into granules together with anions except nitrates which remained on surface of potato starch granules. Cations facilitated the starch thermal decomposition in accordance with values of their standard redox potentials. Nitrates supported this process only in the presence of base metal cations.

  10. Six-Membered-Ring Malonatoborate-Based Lithium Salts as Electrolytes for Lithium Ion Batteries

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Li; Zhang, Hanjun; Driscoll, Peter; Lucht, Brett; Kerr, John

    2011-09-30

    A new class of lithium salts of malonatoborate anions has been synthesized. These six-membered-ring salts provided slightly lower ionic conductivity than that of LiBOB and LiBF4. Nevertheless, compared with LiBOB and LiPF6, the lowered ring strains in the malonatoborate structures and reduced numbers of fluorine atoms in the molecules was found to enhance the thermal and water stabilities and compatibilities of these salts with ether solvents. Small amount LiDMMDFB when used as an additive, was found to stabilize LiPF6 in carbonate electrolytes at 80°C for one month. Employing LiMDFB as the electrolyte in Li/Li cells and full cells, large interfacial impedances were observed on lithium metal and the cathode. Moreover, the large impedances are at least partially attributed to the acidic hydrogen atoms in the malonate structure. This issue can be addressed by replacing the acidic atoms with methyl groups.

  11. An investigation into the electrochemical recovery of rare earth ions in a CsCl-based molten salt

    Energy Technology Data Exchange (ETDEWEB)

    Jiao, Shuqiang, E-mail: sjiao@ustb.edu.cn [School of Metallurgical and Ecological Engineering, University of Science and Technology Beijing, Beijing, 100083 (China); Zhu, Hongmin, E-mail: hzhu@metall.ustb.edu.cn [School of Metallurgical and Ecological Engineering, University of Science and Technology Beijing, Beijing, 100083 (China)

    2011-05-30

    A CsCl-based melt, was used as a supporting electrolyte for a fuel cycle in pyrochemical separation, as it has a high solubility for lanthanide oxide. Cyclic voltammetry and square wave voltammetry were carried out to investigate the cathodic reduction of those rare earth ions. The results prove that the cathodic process of La(III) ions dissolved in a CsCl-based melt, with a one-step reduction La{sup 3+} + 3e{sup -} = La, and is similar to those of other reports which have utilised LiCl-KCl or CaCl{sub 2}-KCl molten salt systems. However, for the Ce(III) ions that dissolved in a CsCl-based melt, there is a significant difference when compared with published literature as there are two reduction steps instead of the reported single step Ce{sup 3+} + e{sup -} = Ce{sup 2+} and Ce{sup 2+} + 2e{sup -} = Ce. In order to explain the novel result, a detailed investigation was focused on the cathodic process of Ce(III) in a CsCl-based melt. The identification of the M-O (M = La, Ce) compounds that are stable in the electrolyte, as well as the determination of their solubility products, were carried out by potentiometric titration using an oxide ion sensor. Furthermore, the E-pO{sup 2-} (potential-oxide ion) diagram for the M-O stable compound was constructed by combining both theoretical and experimental data.

  12. High-field asymmetric waveform ion mobility spectrometry for determining the location of in-source collision-induced dissociation in electrospray ionization mass spectrometry.

    Science.gov (United States)

    Xia, Yuan-Qing; Jemal, Mohammed

    2009-09-15

    The understanding and control of the in-source collision-induced dissociation (CID) of analytes is important for the accurate LC-MS/MS quantitation of drugs and metabolites in biological samples. Accordingly, it was of interest to us to establish whether such in-source CID takes place after and/or before the orifice of an electrospray ionization (ESI) mass spectrometer. A high-field asymmetric waveform ion mobility spectrometry (FAIMS) system that is physically located between the sprayer and the orifice of a mass spectrometer can serve as an ion filter to control ions entering the orifice of the mass spectrometer. In such a configuration, FAIMS could conceivably be used to determine if the in-source CID of an analyte occurs after and/or before the mass spectrometer orifice. We demonstrated this capability of FAIMS using ifetroban acylglucuronide metabolite as a model compound. Under the conditions used, the results showed that the in-source CID conversion of the acylglucuronide metabolite to its parent drug ifetroban occurred almost entirely after the orifice of the mass spectrometer, with the conversion upstream of the orifice accounting for only 5.6% of the conversion. Under the circumstance, the term "post-orifice CID" rather than "in-source CID" may be more appropriate in describing such a dissociation occurring in the front end of a mass spectrometer.

  13. The salt and lipid composition of model cheeses modifies in-mouth flavour release and perception related to the free sodium ion content.

    Science.gov (United States)

    Boisard, Lauriane; Andriot, Isabelle; Martin, Christophe; Septier, Chantal; Boissard, Vanessa; Salles, Christian; Guichard, Elisabeth

    2014-02-15

    Reducing salt and lipid levels in foodstuffs without any effect on acceptability is a major challenge, particularly because of their interactions with other ingredients. This study used a multimodal approach to understand the effects of changes to the composition of model cheeses (20/28, 24/24, 28/20 lipid/protein ratios, 0% and 1% added NaCl) on sodium ion mobility ((23)Na NMR), in-mouth sodium release and flavour perception. An increase in the salt content decreased cheese firmness and perceived hardness, and increased sodium ion mobility, in vivo sodium release and both saltiness and aroma perception. With the same amount of salt, a lower lipid/protein ratio increased the firmness of the cheeses, perceived hardness, and decreased sodium ion mobility, in vivo sodium release, saltiness and aroma perception. These findings suggest on one hand that it could be possible to increase saltiness perception by varying cheese composition, thus inducing differences in sodium ion mobility and in free sodium ion concentration, leading to differences in in-mouth sodium release and saltiness perception, and on the other hand that the reformulation of foods in line with health guidelines needs to take account of both salt content and the lipid/protein ratio.

  14. Interfacial behavior of perchlorate versus chloride ions in saturated aqueous salt solutions

    Energy Technology Data Exchange (ETDEWEB)

    Ghosal, S; Kuo, I W; Baer, M D; Bluhm, H

    2009-04-14

    In recent years combination of theoretical and experimental work have presented a novel view of the aqueous interface wherein hard and/or multiply charged ions are excluded from the interface, but large polarizable anions show interfacial enhancement relative to the bulk. The observed trend in the propensity of anions to adsorb at the air/water interface appears to be reverse of the Hofmeister series for anions. This study focuses on experimental and theoretical examination of the partitioning behavior of perchlorate (ClO{sub 4}{sup -}) and chloride (Cl{sup -}) ions at the air/water interface. We have used ambient pressure X-ray photoelectron spectroscopy technique to directly probe the interfacial concentrations of ClO{sub 4}{sup -} and Cl{sup -} ions in sodium perchlorate and sodium chloride solutions, respectively. Experimental observations are compared with first principles molecular dynamics simulations. Both experimental and simulation results show enhancement of ClO{sub 4}{sup -} ion at the interface, compared with the absence of such enhancement in the case of Cl{sup -} ion. These observations are in agreement with the expected trend in the interfacial propensity of anions based on the Hofmeister series.

  15. Structure characterization and electrochemical properties of new lithium salt LiODFB for electrolyte of lithium ion batteries

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Lithium difluoro(axalato)borate (LiODFB) was synthesized in dimethyl carbonate (DMC) solvent and purified by the method of solventing-out crystallization.The structure characterization of the purified LiODFB was performed by Fourier transform infrared (FTIR) spectrometry and nuclear magnetic resonance (NMR) spectrometry.The electrochemical properties of the cells using I mol/L LiPF6 and 1 mol/L LiODFB in ethylene carbonate (EC)/DMC were investigated,respectively.The results indicate that LiODFB can be reduced at about 1.5 V and form a robust protective solid electrolyte interface (SEI) film on the graphite surface in the first cycle.The graphite/LiNi1/3Mn1/3Co1/3O2 cells with LiODFB-based electrolyte have very good capacity retention at 55 ℃,and show very good rate capability at 0.5C and 1C charge/discharge rate.Therefore,as a new salt,LiODFB is a most promising alternative lithium salt to replace LiPF6 for lithium ion battery electrolytes in the future.

  16. Interaction modes between asymmetrically and oppositely charged rods.

    Science.gov (United States)

    Antila, Hanne S; Van Tassel, Paul R; Sammalkorpi, Maria

    2016-02-01

    The interaction of oppositely and asymmetrically charged rods in salt-a simple model of (bio)macromolecular assembly-is observed via simulation to exhibit two free energy minima, separated by a repulsive barrier. In contrast to similar minima in the Derjaguin-Landau-Verwey-Overbeek (DLVO) theory, the governing mechanism includes electrostatic attraction at large separation, osmotic repulsion at close range, and depletion attraction near contact. A model accounting for ion condensation and excluded volume is shown to be superior to a mean-field treatment in predicting the effect of charge asymmetry on the free-energy profile.

  17. Variation in viscosity and ion conductivity of a polymer–salt complex exposed to gamma irradiation

    Indian Academy of Sciences (India)

    Sujata Tarafdar; S K De; Sujit Manna; Udayan De; Pradyot Nanda

    2010-02-01

    We study changes in microstructure and resulting changes in the properties of PEO(1 − )–NH4 ClO4 () samples where = 0.18, when irradiated with gamma doses varying up to 50 kGy. Viscosities of aqueous solutions of the irradiated samples give an idea of the change in molecular weight and show correlation with ion conductivity. On the whole, there is a chain scission on irradiation, though there is evidence of some cross-linking at higher doses. The ion conductivity shows a strong increase for an irradiation of 35 kGy. DSC studies indicate a decrease in crystallinity with gamma dose.

  18. Novel symmetric diimine-Schiff bases and asymmetric triimine-Schiff bases as chemosensors for the detection of various metal ions

    Science.gov (United States)

    Özdemir, Özlem

    2016-12-01

    In this study, two symmetric diimine-Schiff bases (D1, D2) containing nitro group were synthesized by a simple one-pot condensation of 4-nitro-o-phenylenediamine with substituted-salicylaldehyde (5-Cl, 5-CH3) in 1:2 ratio. After the selective reduction of nitro group to amino group by using sodium dithionite and forming the new imine bond by adding substituted-salicylaldehyde or 2-hydroxy-1-naphthaldehyde, four asymmetric triimine-Schiff bases (T1s, T1n, T2s, and T2n) were obtained. Results of the newly synthesized compounds established by elemental analyses, FT-IR, UV-vis, 2D NMR (HMQC), 1H-NMR, 13C-NMR and TOF-mass spectroscopic experiments were consistent with their chemical structures. The tautomeric equilibria were also studied. The sensor properties of all Schiff bases were examined upon addition of the metal ions, such as Cr3+, Fe2+, Fe3+, Co2+, Ni2+, Cu2+, Zn2+, and Pb2+. The interactions between receptors and ions are easily monitored by UV-vis method. The receptor D2 showed colour changes from yellow to intense deep orange colour for Cu2+, a orange colour for Co2+ and dark yellow colour for other ions. Although metal ions caused no change in colour of T2s, the main absorption band of receptor shifted from 351 nm to 343-372 nm T2n underwent colour changes from yellow to light yellow on gradual addition of Fe3+.

  19. Catalytic Asymmetric Synthesis of Both Enantiomers of 4‑Substituted 1,4-Dihydropyridines with the Use of Bifunctional Thiourea-Ammonium Salts Bearing Different Counterions

    Directory of Open Access Journals (Sweden)

    Kohzo Yoshida

    2010-11-01

    Full Text Available Organoammonium salts composed of a Brønsted acid and an anilinothiourea promoted the Michael addition of β-keto esters and α,β-unsaturated aldehydes in the presence of primary amines to give functionalized 1,4-dihydropyridines enantioselectively. With the use of the different Brønsted acids such as DFA and HBF4 with the same bifunctional thiourea, both enantiomers of 4-substituted 1,4-dihydropyridine were synthesized from the same starting materials.

  20. Interactive toxicity of major ion salts: Comparisons among species and between acute and chronic endpoints

    Science.gov (United States)

    Increased concentrations of major ions (Na, K, Ca, Mg, Cl, SO4, HCO3) in freshwater systems can result from a variety of anthropogenic activities, and can adversely affect aquatic organisms if the increase is sufficiently severe. Laboratory tests have indicated that the toxicity...

  1. The acute toxicity of major ion salts to Ceriodaphnia dubia: I. Influence of background water chemistry

    Science.gov (United States)

    The ions Na+, K+, Ca2+, Mg2+, Cl-, SO42-, and HCO3-/CO32- (referred to as “major ions”) are present in all fresh waters and are physiologically required by aquatic organisms, but can be increased to harmful levels by a variety of anthropogenic activities that speed ge...

  2. The Catalytic Asymmetric Intramolecular Stetter Reaction.

    Science.gov (United States)

    de Alaniz, Javier Read; Rovis, Tomislav

    2009-05-01

    This account chronicles our efforts at the development of a catalytic asymmetric Stetter reaction using chiral triazolium salts as small molecule organic catalysts. Advances in the mechanistically related azolium-catalyzed asymmetric benzoin reaction are discussed, particularly as they apply to catalyst design. A chronological treatise of reaction discovery, catalyst optimization and reactivity extension follows.

  3. Synthesis of rock-salt type lithium borohydride and its peculiar Li+ ion conduction properties

    Directory of Open Access Journals (Sweden)

    R. Miyazaki

    2014-05-01

    Full Text Available The high energy density and excellent cycle performance of lithium ion batteries makes them superior to all other secondary batteries and explains why they are widely used in portable devices. However, because organic liquid electrolytes have a higher operating voltage than aqueous solution, they are used in lithium ion batteries. This comes with the risk of fire due to their flammability. Solid electrolytes are being investigated to find an alternative to organic liquid. However, the nature of the solid-solid point contact at the interface between the electrolyte and electrode or between the electrolyte grains is such that high power density has proven difficult to attain. We develop a new method for the fabrication of a solid electrolyte using LiBH4, known for its super Li+ ion conduction without any grain boundary contribution. The modifications to the conduction pathway achieved by stabilizing the high pressure form of this material provided a new structure with some LiBH4, more suitable to the high rate condition. We synthesized the H.P. form of LiBH4 under ambient pressure by doping LiBH4 with the KI lattice by sintering. The formation of a KI - LiBH4 solid solution was confirmed both macroscopically and microscopically. The obtained sample was shown to be a pure Li+ conductor despite its small Li+ content. This conduction mechanism, where the light doping cation played a major role in ion conduction, was termed the “Parasitic Conduction Mechanism.” This mechanism made it possible to synthesize a new ion conductor and is expected to have enormous potential in the search for new battery materials.

  4. A systematic investigation of quaternary ammonium ions as asymmetric phase-transfer catalysts. Application of quantitative structure activity/selectivity relationships.

    Science.gov (United States)

    Denmark, Scott E; Gould, Nathan D; Wolf, Larry M

    2011-06-01

    Although the synthetic utility of asymmetric phase-transfer catalysis continues to expand, the number of proven catalyst types and design criteria remains limited. At the origin of this scarcity is a lack in understanding of how catalyst structural features affect the rate and enantioselectivity of phase transfer catalyzed reactions. Described in this paper is the development of quantitative structure-activity relationships (QSAR) and -selectivity relationships (QSSR) for the alkylation of a protected glycine imine with libraries of quaternary ammonium ion catalysts. Catalyst descriptors including ammonium ion accessibility, interfacial adsorption affinity, and partition coefficient were found to correlate meaningfully with catalyst activity. The physical nature of the descriptors was rationalized through differing contributions of the interfacial and extraction mechanisms to the reaction under study. The variation in the observed enantioselectivity was rationalized employing a comparative molecular field analysis (CoMFA) using both the steric and electrostatic fields of the catalysts. A qualitative analysis of the developed model reveals preferred regions for catalyst binding to afford both configurations of the alkylated product.

  5. Determination of melamine in milk and dairy products by microchip-based high-field asymmetric ion mobility spectrometry combined with solid-phase extraction.

    Science.gov (United States)

    Zhao, Wei-jun; Wang, Yonghuan; Li, Juan; Li, Ling-feng; Wang, Qi; Han, Ke; Zhang, Yuang; Li, Xin; Li, Peng; Luo, Jikui; Wang, Xiaozhi

    2015-12-01

    This article presents a method for sensitive, fast and quantitative determination of melamine in milk and dairy products using high-field asymmetric ion mobility spectrometry (FAIMS). The solid-phase extraction (SPE) technology was used for purification after the sample was extracted by organic solvents, and followed by the analysis of FAIMS. The measurement parameters and variables that affect the FAIMS detection have been investigated, and optimum conditions have been obtained as follows: the carrier gas flow rate is 1.6 L min(-1), the headspace sampler temperature is 150 °C, the pressure is 1 atm, and the humidity is 2.0 g m(-3). The results showed that the SPE-FAIMS method can detect melamine in samples with a concentration down to 0.1 mg kg(-1). The ion intensity has a linear relationship with melamine concentration in the range from 0.3 mg L(-1) to 25 mg L(-1), with a good linearity of 0.9975. The limits of detection (LOD) and limits of quantification (LOQ) are 0.1 mg kg(-1) and 0.3 mg kg(-1) in milk and dairy products, respectively, and the relative standard deviation is less than 8.0%. The results demonstrated that FAIMS has great potential as a powerful tool for food analysis and safety inspection.

  6. Molten salt synthesis of sodium lithium titanium oxide anode material for lithium ion batteries

    Energy Technology Data Exchange (ETDEWEB)

    Yin, S.Y., E-mail: yshy2004@hotmail.com [College of Environmental and Biological Engineering, Wuhan Technology and Business University, Wuhan 430065 (China); Feng, C.Q. [Hubei Collaborative Innovation Center for Advanced Organic Chemical Materials, Ministry of Education Key Laboratory for Synthesis and Applications of Organic Functional Molecules, Hubei University, Wuhan 430062 (China); Wu, S.J.; Liu, H.L.; Ke, B.Q. [College of Environmental and Biological Engineering, Wuhan Technology and Business University, Wuhan 430065 (China); Zhang, K.L. [College of Chemistry and Molecular Sciences, Wuhan University, Wuhan 430072 (China); Chen, D.H. [College of Environmental and Biological Engineering, Wuhan Technology and Business University, Wuhan 430065 (China); Hubei Key Laboratory for Catalysis and Material Science, College of Chemistry and Material Science, South Central University for Nationalities, Wuhan 430074, Hubei (China)

    2015-09-05

    Highlights: • Na{sub 2}Li{sub 2}Ti{sub 6}O{sub 12} has been successfully synthesized via a molten salt route. • Calcination temperature is an important effect on the component and microstructure of the product. • Pure phase Na{sub 2}Li{sub 2}Ti{sub 6}O{sub 12} could be obtained at 700 °C for 2 h. - Abstract: The sodium lithium titanium oxide with composition Na{sub 2}Li{sub 2}Ti{sub 6}O{sub 14} has been synthesized by a molten salt synthesis method using sodium chloride and potassium chloride mixture as a flux medium. Synthetic variables on the synthesis, such as sintering temperature, sintering time and the amount of lithium carbonate, were intensively investigated. Powder X-ray diffraction and scanning electron microscopy images of the reaction products indicates that pure phase sodium lithium titanium oxide has been obtained at 700 °C, and impure phase sodium hexatitanate with whiskers produced at higher temperature due to lithium evaporative losses. The results of cyclic voltammetry and discharge–charge tests demonstrate that the synthesized products prepared at various temperatures exhibited electrochemical diversities due to the difference of the components. And the sample obtained at 700 °C revealed highly reversible insertion and extraction of Li{sup +} and displayed a single potential plateau at around 1.3 V. The product obtained at 700 °C for 2 h exhibits good cycling properties and retains the specific capacity of 62 mAh g{sup −1} after 500 cycles.

  7. Effect of phytohormones on absorption and distribution of ions in salt-stressed bean plants

    Directory of Open Access Journals (Sweden)

    Zofia Starck

    2014-02-01

    Full Text Available Bean plant seedlings grown in water culture were treated for 5 days either with NaCl or with 7-times concentrated nutrient solution (diminished water potential by 3-103 hPa in both cases. Control and stressed plants were treated for 24 hrs with zeatin and GA,. NaCl-stress reduced distinctly ion absorption rate (K, Ca and P. Zeatin and GA3 promoted potassium uptake, but only in NaCI-treated plants. These hormones diminished Na accumulation in metabolically active organs but increased P- and Ca-content. In plants grown under both kind of stresses zeatin and GA3 partially reestablished the ratio of the main mono- to divalent cations, which increased in the leaves and apical part of the stressed plants. ABA introduced into the nutrient solution caused inhibition of the ion uptake (K, Ca, Mg and P. similar to that caused by NaCl-stress. The above reported results seem to confirm the supposition, that hormones act as an important factor contributing to regulation of both uptake and distribution of ions. In this way growth substances may also participate in the regulation of transport of various substances (among others - assimilates in the whole plant.

  8. Ion recognition: application of symmetric and asymmetric schiff bases and their complexes for the fabrication of cationic and anionic membrane sensors to determine ions in real samples.

    Science.gov (United States)

    Faridbod, Farnoush; Ganjali, Mohammad Reza; Dinarvand, Rassoul; Norouzi, Parviz

    2007-08-01

    Schiff base compounds refer to the branch of supra-molecules and can be used as sensing material in the construction of potentiometric ion selective electrodes (ISEs). This relatively modern field has been subject to extensive research in the period of 1999-2007 when more than 100 ISEs employing Schiff bases were constructed. The quantitative high-throughput detection of 29 cations and 7 anions has been demonstrated in various scientific branches, such as biomedicine, pharmacy, biochemistry, pharmacology, environmental chemistry, food technology, and agriculture. This review discusses Schiff base compounds and their applications in the design and development of ion selective sensors and microsensors.

  9. Effect of Dopant Ions on the Electrical Conductivity and Microstructure of Polyaniline (Emeraldine Salt

    Directory of Open Access Journals (Sweden)

    M. D. Catedral

    2004-12-01

    Full Text Available Samples of polyaniline (emeraldine salt were prepared with different protonic acid dopants, namely, hydrochloric acid (HCl, nitric acid (HNO3, perchloric acid (HClO4, sulfuric acid (H2SO4, and hydroiodic acid (HI. Using the two-point probe method, it was found that the samples had ohmic behaviors in which high linear coefficients were found in the range 0.9686–0.9997. On the other hand, the electrical conductivities were measured using the Van der Pauw method. The undoped sample had a conductivity of 5x10–4 S/cm. The highest conductivity of 109.04 S/cm was observed for the HClO4-doped sample, while the lowest value (0.02 S/cm was obtained for the HI-doped sample. These conductivities were compared with the computed energy gap between the highest occupied molecular orbital (HOMO and lowest unoccupied molecular orbital (LUMO where it was found that they are inversely proportional to each other. Scanning electron microscopy revealed significant differences among the samples in terms of shapes and morphologies.

  10. Synthesis and Self-Assembly of Triangulenium Salts

    DEFF Research Database (Denmark)

    Shi, Dong

    This thesis describes the design and synthesis of asymmetrically substituted amphiphilic tis(dialkylamino)trioxiatriangulenium (ATOTA+) salts with different counter ions. Attention was focused on exploring the assembling properties of the ATOTA+ salts in aqueous media. A direct vortexing....... Addition of soft counter ion into the nanosheets solution could induce gluing of the nanosheets. The solid thin film formed from the formed nanosheets after water evaporation showed crystalline patterning order as revealed by x-ray diffraction (XRD) measurements. Chpater 5 reports the counter ion effect...... in our group. The motivation of this project is to find potential application of the fluorescence sensor in biolabeling and bioimaging techniques. Chapter 8 is a brief summary of the thesis....

  11. Enhanced salt-removal percentage in capacitive deionization with addition of ion-exchange membrane using carbon electrode synthesized with freezing thawing method

    Science.gov (United States)

    Sari, Intan Permata; Endarko

    2016-04-01

    Ion-exchange membrane technology has shown a great potential to enhance the desalting efficiency. Ion-exchange membranes are placed in front of the electrodes so that the charged ions can be selectively passed through the membrane layer and captured by the oppositely charged electrode more quickly, so as to increase the efficiency of desalination. In this research, carbon electrodes have been synthesized from an activated carbon (700 - 1400 m2/g) and polyvinyl alcohol (PVA) as a binder using freezing thawing method. A solution with 180 µS/cm NaCl was pumped to the capacitive deionization (CDI) cell using a Boyu Submersible pump (model SP-601) at a flow rate of 25 mL/min and the voltage was set at 2 V. The result showed that the CDI cell with ion-exchange membrane (MCDI) has the salt removal efficiency greater than the CDI cell without ion-exchange membrane. The salt-removal percentage of MCDI was achieved at 66.36%, meanwhile the CDI cell without ion-exchange membrane resulted in 54.4%.

  12. Trace level impurity method development with high-field asymmetric waveform ion mobility spectrometry: systematic study of factors affecting the performance.

    Science.gov (United States)

    Champarnaud, Elodie; Laures, Alice M-F; Borman, Phil J; Chatfield, Marion J; Kapron, James T; Harrison, Mark; Wolff, Jean-Claude

    2009-01-01

    For the determination of trace level impurities, analytical chemists are confronted with complex mixtures and difficult separations. New technologies such as high-field asymmetric waveform ion mobility spectrometry (FAIMS) have been developed to make their work easier; however, efficient method development and troubleshooting can be quite challenging if little prior knowledge of the factors or their settings is available. We present the results of an investigation performed in order to obtain a better understanding of the FAIMS technology. The influence of eight factors (polarity of dispersion voltage, outer bias voltage, total gas flow rate, composition of the carrier gas (e.g. %He), outer electrode temperature, ratio between the temperatures of the inner and outer electrodes, flow rate and composition of the make-up mobile phase) was assessed. Five types of responses were monitored: value of the compensation voltage (CV), intensity, width and asymmetry of the compensation voltage peak, and resolution between two peaks. Three types of studies were performed using different test mixtures and various ionisation modes to assess whether the same conclusions could be drawn across these conditions for a number of different types of compounds. To extract the maximum information from as few experiments as possible, a Design of Experiment (DoE) approach was used. The results presented in this work provide detailed information on the factors affecting FAIMS separations and therefore should enable the user to troubleshoot more effectively and to develop efficient methods.

  13. Scanning ion-selective electrode technique and X-ray microanalysis provide direct evidence of contrasting Na+ transport ability from root to shoot in salt-sensitive cucumber and salt-tolerant pumpkin under NaCl stress.

    Science.gov (United States)

    Lei, Bo; Huang, Yuan; Sun, Jingyu; Xie, Junjun; Niu, Mengliang; Liu, Zhixiong; Fan, Molin; Bie, Zhilong

    2014-12-01

    Grafting onto salt-tolerant pumpkin rootstock can increase cucumber salt tolerance. Previous studies have suggested that this can be attributed to pumpkin roots with higher capacity to limit the transport of Na(+) to the shoot than cucumber roots. However, the mechanism remains unclear. This study investigated the transport of Na(+) in salt-tolerant pumpkin and salt-sensitive cucumber plants under high (200 mM) or moderate (90 mM) NaCl stress. Scanning ion-selective electrode technique showed that pumpkin roots exhibited a higher capacity to extrude Na(+), and a correspondingly increased H(+) influx under 200 or 90 mM NaCl stress. The 200 mM NaCl induced Na(+)/H(+) exchange in the root was inhibited by amiloride (a Na(+)/H(+) antiporter inhibitor) or vanadate [a plasma membrane (PM) H(+) -ATPase inhibitor], indicating that Na(+) exclusion in salt stressed pumpkin and cucumber roots was the result of an active Na(+)/H(+) antiporter across the PM, and the Na(+)/H(+) antiporter system in salt stressed pumpkin roots was sufficient to exclude Na(+) X-ray microanalysis showed higher Na(+) in the cortex, but lower Na(+) in the stele of pumpkin roots than that in cucumber roots under 90 mM NaCl stress, suggesting that the highly vacuolated root cortical cells of pumpkin roots could sequester more Na(+), limit the radial transport of Na(+) to the stele and thus restrict the transport of Na(+) to the shoot. These results provide direct evidence for pumpkin roots with higher capacity to limit the transport of Na(+) to the shoot than cucumber roots.

  14. PENENTUAN KADAR IODIDA DAN IODAT DALAM GARAM BERIODIUM DENGAN METODE KROMATOGRAFI CAIR KENERJA TINGGI PASANGAN ION [Determination of Iodate and Iodide Content in Iodized Salt By Ion Pair High Performance Liquid Chromatography Method

    Directory of Open Access Journals (Sweden)

    Wisnu Cahyadi1

    2004-04-01

    Full Text Available Two species of iodine, i.e. iodide and iodate in commercial iodized salt were determined using ion pair HPLC. From 15 samples analysed, the iodide and iodate content ranged from 24,05 ± 2,51 to 70,25 ± 3,78 ppm and from 31,43 ± 8,10 to 87,59 ± 0,44 ppm, respectively. The method used was found satisfactory in terms of precission, accuracy, sensitivity and selectivity, therefore the method seem acceptable for the determination of iodide and iodate content in iodized salt samples.

  15. Coulombic free energy and salt ion association per phosphate of all-atom models of DNA oligomer: dependence on oligomer size.

    Science.gov (United States)

    Shkel, Irina A; Record, M Thomas

    2012-08-23

    We investigate how the coulombic Gibbs free energy and salt ion association per phosphate charge of DNA oligomers vary with oligomer size (i.e. number of charged residues ∣ZD∣) at 0.15 M univalent salt by non-linear Poisson Boltzmann (NLPB) analysis of all-atom DNA models. Calculations of these quantities ([Formula: see text], [Formula: see text]) are performed for short and long double-stranded (ds) and single-stranded (ss) DNA oligomers, ranging from 4 to 118 phosphates (ds) and from 2 to 59 phosphates (ss). Behaviors of [Formula: see text] and [Formula: see text] as functions of ∣ZD∣ provide a measure of the range of the coulombic end effect and determine the size of an oligomer at which an interior region with the properties (per charge) of the infinite-length polyelectrolyte first appears. This size (10-11 phosphates at each end for ds DNA and 6-9 for ss DNA at 0.15 M salt) is in close agreement with values obtained previously by Monte Carlo and NLPB calculations for cylindrical models of polyions, and by analysis of binding of oligocations to DNA oligomers. Differences in [Formula: see text] and in [Formula: see text] between ss and ds DNA are used to predict effects of oligomeric size and salt concentration on duplex stability in the vicinity of 0.15 M salt. Results of all-atom calculations are compared with results of less structurally detailed models and with experimental data.

  16. Salts and nutrients present in regenerated waters induce changes in water relations, antioxidative metabolism, ion accumulation and restricted ion uptake in Myrtus communis L. plants.

    Science.gov (United States)

    Acosta-Motos, José R; Alvarez, Sara; Barba-Espín, Gregorio; Hernández, José A; Sánchez-Blanco, María J

    2014-12-01

    The use of reclaimed water (RW) constitutes a valuable strategy for the efficient management of water and nutrients in landscaping. However, RW may contain levels of toxic ions, affecting plant production or quality, a very important aspect for ornamental plants. The present paper evaluates the effect of different quality RWs on physiological and biochemical parameters and the recovery capacity in Myrtus communis L. plants. M. communis plants were submitted to 3 irrigation treatments with RW from different sources (22 weeks): RW1 (1.7 dS m(-1)), RW2 (4.0 dS m(-1)) and RW3 (8.0 dS m(-1)) and one control (C, 0.8 dS m(-1)). During a recovery period of 11 weeks, all plants were irrigated with the control water. The RW treatments did not negatively affect plant growth, while RW2 even led to an increase in biomass. After recovery,only plants irrigated with RW3 showed some negative effects on growth, which was related to a decrease in the net photosynthesis rate, higher Na accumulation and a reduction in K levels. An increase in salinity was accompanied by decreases in leaf water potential, relative water content and gas exchange parameters, and increases in Na and Cl uptake. Plants accumulated Na in roots and restricted its translocation to the aerial part. The highest salinity levels produced oxidative stress, as seen from the rise in electrolyte leakage and lipid peroxidation. The use of regenerated water together with carefully managed drainage practices, which avoid the accumulation of salt by the substrate, will provide economic and environmental benefits.

  17. Evaluation and elimination of inhibitory effects of salts and heavy metal ions on biodegradation of Congo red by Pseudomonas sp. mutant.

    Science.gov (United States)

    Gopinath, Kannappan Panchamoorthy; Kathiravan, Mathur Natarajan; Srinivasan, Raman; Sankaranarayanan, Subramanian

    2011-02-01

    In this study, it was attempted to evaluate the influences and also recommended some elimination methods for inhibitory effects offered by salts and heavy metal ions. Congo red dye solution treated with mutant Pseudomonas sp. was taken as a model system for study. The salts used in this study are NaCl, CaCl(2) and MgSO(4)· 7H(2)O. Though the growth was inhibited at concentrations above 4 g/l, toleration was achieved by acclimatization process. In case of heavy metal ions, Cr (VI) showed low inhibition up to 500 mg/l of concentration, compared to Zn (II) and Cu (II). It was due to the presence of chromium reductase enzyme which was confirmed by SDS-PAGE. Zn (II) and Cu (II) ion inhibitions were eliminated by chelation with EDTA. The critical ion concentrations obtained as per Han-Levenspiel model for Cr (VI), Zn (II) and Cu (II) were 0.8958, 0.3028 and 0.204 g/l respectively.

  18. Hydronium-dominated ion transport in carbon-dioxide-saturated electrolytes at low salt concentrations in nanochannels

    DEFF Research Database (Denmark)

    Pennathur, Sumita; Kristensen, Jesper; Crumrine, Andrew

    2011-01-01

    conductance for low salt concentrations, we identify a minimum conductance value before saturation at a value independent of salt concentration in the dilute limit. Our model self-consistently couples chemical equilibrium models of the silica wall and the electrolyte bulk, and is parameterized by only...

  19. Hydronium-dominated ion transport in carbon-dioxide-saturated electrolytes at low salt concentrations in nanochannels

    DEFF Research Database (Denmark)

    Lund Jensen, Kristian; Kristensen, Jesper Toft; Crumrine, Andrew Michael

    2011-01-01

    the nanochannel conductance at low salt concentrations and identify a conductance minimum before saturation at a value independent of salt concentration in the dilute limit. Via the Poisson-Boltzmann equation, our model self-consistently couples chemical-equilibrium dissociation models of the silica wall...

  20. Asymmetrical orientation weighted mean filter for salt-and-pepper noise removing%去除椒盐噪声的非对称有向窗加权均值滤波

    Institute of Scientific and Technical Information of China (English)

    郭明; 朱敏; 周晓东

    2011-01-01

    针对传统滤波对称窗口在图像边缘处会引入干扰像素引起图像模糊的问题,提出一种非对称有向窗加权均值滤波算法.首先,基于区域极值进行噪声检测;其次,在对称有向窗的基础上提出非对称有向窗的概念,对于噪声点,通过标准差最小的原则自适应选择非对称有向滤波窗口;然后,在选择的非对称有向滤波窗口内对噪声点进行自适应基于距离倒数的加权均值滤波;最后,根据滤波结果对噪声点进行二次确认,纠正前面噪声检测中误检的噪声点.仿真实验表明,该方法在去噪效果和边缘保持性能及运算速度上都优于基于对称有向窗滤波算法,而且与传统的中值滤波法及其一些改进算法相比,也表现出了更优越的性能.%Because a few interferential pixels will be involved in the filter operation when the traditional filter based on symmetrical window is used, image blurring always occurs in traditional image filtering. This paper presents an asymmetrical orientation weighted mean filter to remove the salt-and-pepper noise in the images. Firstly, the noise pixels are detected based on regional gray extreme value. Secondly, a concept of asymmetrical orientation window is proposed based on symmetrical orientation window,and the actual filter window of noise pixel is selected adaptively according to the principle that the filter window has the minimal standard deviation. Then, a weighted mean filter that the weight value is inverse proportional to the distance to the filter pixel is performed in the selected asymmetrical window. Lastly, a secondary confirmation to the noise pixel is carried out for correcting the wrong-checked noise pixel in forward noise detection. The experimental results show that the proposed algorithm outperforms the algorithms based on symmetrical window in aspects of noise removing, preserving of image edge and processing speed. Comparing with the traditional median filter

  1. Interpretation with a Donnan-based concept of the influence of simple salt concentration on the apparent binding of divalent ions to the polyelectrolytes polystyrenesulfonate and dextran sulfate

    Science.gov (United States)

    Marinsky, J.A.; Baldwin, Robert F.; Reddy, M.M.

    1985-01-01

    It has been shown that the apparent enhancement of divalent metal ion binding to polyions such as polystyrenesulfonate (PSS) and dextran sulfate (DS) by decreasing the ionic strength of these mixed counterion systems (M2+, M+, X-, polyion) can be anticipated with the Donnan-based model developed by one of us (J.A.M.). Ion-exchange distribution methods have been employed to measure the removal by the polyion of trace divalent metal ion from simple salt (NaClO4)-polyion (NaPSS) mixtures. These data and polyion interaction data published earlier by Mattai and Kwak for the mixed counterion systems MgCl2-LiCl-DS and MgCl2-CsCl-DS have been shown to be amenable to rather precise analysis by this model. ?? 1985 American Chemical Society.

  2. The Influence of Nitrate Salts and Complex Metal Ion to Regio-Selective Synthesis of 2-Nitro-5,10,15,20-Tetra-(4-Methoxyphenyl)Porphyrinato Metal

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    A series of 2-nitro-5,10,15,20-tetra(4-methoxyphenyl) porphyrinato metals were regioselectively synthesized with nitrate salts as nitrating reagent in acetic acid/acetic anhydride for preparation of 2-substituted porphyrin. The influence of nitrate salts and complex metal ion to the reaction were investigated. The extent of 2-nitration increased with the electronegativity of the central metal. When Cu(NO3)2·3H2O was used as nitrating reagent, almost quantitative yields of 2 nitro porphyrin were obtained in the case of Cu(Ⅱ) or Ni(Ⅱ) chelates, while Zn(Ⅱ) or Mn(Ⅲ) chelates gave 50% and 30% yields respectively. If Zn(NO3)2·10H2O was used as nitrating agent, no product was found for Cu(Ⅱ) or Ni(Ⅱ) chelates, 12% was found for Zn(Ⅱ) chelates. The other metal ion and nitrate salts were also found in quite different influence.

  3. Catalytic Asymmetric Bromocyclization of Polyenes.

    Science.gov (United States)

    Samanta, Ramesh C; Yamamoto, Hisashi

    2017-02-01

    The first catalytic asymmetric bromonium ion-induced polyene cyclization has been achieved by using a chiral BINOL-derived thiophosphoramide catalyst and 1,3-dibromo-5,5-dimethylhydantoin as an electrophilic bromine source. Bromocyclization products are obtained in high yields, with good enantiomeric ratios and high diastereoselectivity, and are abundantly found as scaffolds in natural products.

  4. Mixed-bed ion exchange chromatography employing a salt-free pH gradient for improved sensitivity and compatibility in MudPIT.

    Science.gov (United States)

    Mommen, Geert P M; Meiring, Hugo D; Heck, Albert J R; de Jong, Ad P J M

    2013-07-16

    In proteomics, comprehensive analysis of peptides mixtures necessitates multiple dimensions of separation prior to mass spectrometry analysis to reduce sample complexity and increase the dynamic range of analysis. The main goal of this work was to improve the performance of (online) multidimensional protein identification technology (MudPIT) in terms of sensitivity, compatibility and recovery. The method employs weak anion and strong cation mixed-bed ion exchange chromatography (ACE) in the first separation dimension and reversed phase chromatography (RP) in the second separation dimension (Motoyama et.al. Anal. Chem 2007, 79, 3623-34.). We demonstrated that the chromatographic behavior of peptides in ACE chromatography depends on both the WAX/SCX mixing ratio as the ionic strength of the mobile phase system. This property allowed us to replace the conventional salt gradient by a (discontinuous) salt-free, pH gradient. First dimensional separation of peptides was accomplished with mixtures of aqueous formic acid and dimethylsulfoxide with increasing concentrations. The overall performance of this mobile phase system was found comparable to ammonium acetate buffers in application to ACE chromatography, but clearly outperformed strong cation exchange for use in first dimensional peptide separation. The dramatically improved compatibility between (salt-free) ion exchange chromatography and reversed phase chromatography-mass spectrometry allowed us to downscale the dimensions of the RP analytical column down to 25 μm i.d. for an additional 2- to 3-fold improvement in performance compared to current technology. The achieved levels of sensitivity, orthogonality, and compatibility demonstrates the potential of salt-free ACE MudPIT for the ultrasensitive, multidimensional analysis of very modest amounts of sample material.

  5. A relationship between ion balance and the chemical compounds of salt inclusions found in the Greenland Ice Core Project and Dome Fuji ice cores

    DEFF Research Database (Denmark)

    Johnsen, Sigfus Johann; Dahl-Jensen, Dorthe; Steffensen, Jørgen Peder;

    2008-01-01

    We have proposed a method of deducing the chemical compounds found in deep polar ice cores by analyzing the balance between six major ions (Cl-, NO3 -, SO4 2-, Na+, Mg2+, and Ca2+). The method is demonstrated for the Holocene and last glacial maximum regions of the Dome Fuji and GRIP ice cores...... on individual salt inclusions. The abundances in the ice cores are shown to reflect differences in climatic periods (the acidic environment of the Holocene versus the reductive environment of the last glacial maximum) and regional conditions (the marine environment of Antarctica versus the continental...

  6. Evaluation of layered zinc hydroxide nitrate and zinc/nickel double hydroxide salts in the removal of chromate ions from solutions

    Science.gov (United States)

    de Oliveira, Henrique Bortolaz; Wypych, Fernando

    2016-11-01

    Layered zinc hydroxide nitrate (ZnHN) and Zn/Ni layered double hydroxide salts were synthesized and used to remove chromate ions from solutions at pH 8.0. The materials were characterized by many instrumental techniques before and after chromate ion removal. ZnHN decomposed after contact with the chromate solution, whereas the layered structure of Zn/Ni hydroxide nitrate (Zn/NiHN) and Zn/Ni hydroxide acetate (Zn/NiHA) remained their layers intact after the topotactic anionic exchange reaction, only changing the basal distances. ZnHN, Zn/NiHN, and Zn/NiHA removed 210.1, 144.8, and 170.1 mg of CrO42-/g of material, respectively. Although the removal values obtained for Zn/NiHN and Zn/NiHA were smaller than the values predicted for the ideal formulas of the solids (194.3 and 192.4 mg of CrO42-/g of material, respectively), the measured capacities were higher than the values achieved with many materials reported in the literature. Kinetic experiments showed the removal reaction was fast. To facilitate the solid/liquid separation process after chromium removal, Zn/Ni layered double hydroxide salts with magnetic supports were also synthesized, and their ability to remove chromate was evaluated.

  7. Characterization of Ion Contents and Metabolic Responses to Salt Stress of Different Arabidopsis AtHKT1;1 Genotypes and Their Parental Strains

    Institute of Scientific and Technical Information of China (English)

    Camilla B.Hill; Deepa Jha; Antony Bacic; Mark Tester; Ute Roessner

    2013-01-01

    Plants employ several strategies to maintain cellular ion homeostasis under salinity stress,including mediating ion fluxes by transmembrane transport proteins and adjusting osmotic pressure by accumulating osmolytes.The HKT (high-affinity potassium transporter) gene family comprises Na+ and Na+/K+ transporters in diverse plant species,with HKT1;1 as the only member in Arabidopsis thaliana.Cell-type-specific overexpression of AtHKT1;1 has been shown to prevent shoot Na+ overaccumulation under salinity stress.Here,we analyzed a broad range of metabolites and elements in shoots and roots of different AtHKT1;1 genotypes and their parental strains before and after salinity stress,revealing a reciprocal relationship of metabolite differences between an AtHKT1;1 knockout line (hktl;1) and the AtHKT1;1 overexpressing lines (E2586 UASGAL4:HKT1;1 and J2731*UASGAL4:HKT1;1).Although levels of root sugars were increased after salt stress in both AtHKT1;1 overexpressing lines,E2586 UASGAL4:HKT1;1 showed higher accumulation of the osmoprotectants trehalose,gentiobiose,and melibiose,whereas J2731*UASGAL4:HKT1;1 showed higher levels of sucrose and raffinose,compared with their parental lines,respectively.In contrast,the knockout line hktl;1 showed strong increases in the levels of the tricarboxylic acid (TCA) cycle intermediates in the shoots after salt treatment.This coincided with a significant depletion of sugars,suggesting that there is an increased rate of carbon influx into the TCA cycle at a constant rate of C-efflux from the cycle,which might be needed to support plant survival during salt stress.Using correlation analysis,we identified associations between the Na+ content and several sugars,suggesting that regulation of sugar metabolism is important in plant responses to salinity stress.

  8. Lorentz Force on Sodium and Chlorine Ions in a Salt Water Solution Flow under a Transverse Magnetic Field

    Science.gov (United States)

    De Luca, R.

    2009-01-01

    It is shown that, by applying elementary concepts in electromagnetism and electrochemistry to a system consisting of salt water flowing in a thin rectangular pipe at an average velocity v[subscript A] under the influence of a transverse magnetic field B[subscript 0], an electromotive force generator can be conceived. In fact, the Lorentz force…

  9. Effects of sulfide ions on the integrity of the protective film of benzotriazole on alpha brass in salt water

    Energy Technology Data Exchange (ETDEWEB)

    Ashour, E.A.; Hegazy, H.S.; Ateya, B.G.

    2000-05-01

    The addition of sulfide ions to a solution of 0.58 M NaCl containing benzotriazole (BTAH) results in a decrease of the inhibiting efficiency of BTAH and a momentary increase of the dissolution rate of alpha brass at potentials above the corrosion potential. The effect depends on the sulfide ion concentration and the potential selected for the tests. The results are explained by decomposition of the protective Cu(I)BTA film, caused by the extraction of Cu(I) ions from the film and formation of Cu{sub 2}S: nS{sup 2{minus}} + 2[Cu(I)BTA]{sub n} {yields} nCu{sub 2}S + 2nBTA{sup {minus}}. The breakdown of the film allows metal dissolution from the bare surface and further promotes the effects of sulfide ions.

  10. Trapping of Li(+) Ions by [ThFn](4-n) Clusters Leading to Oscillating Maxwell-Stefan Diffusivity in the Molten Salt LiF-ThF4.

    Science.gov (United States)

    Chakraborty, Brahmananda; Kidwai, Sharif; Ramaniah, Lavanya M

    2016-08-18

    A molten salt mixture of lithium fluoride and thorium fluoride (LiF-ThF4) serves as a fuel as well as a coolant in the most sophisticated molten salt reactor (MSR). Here, we report for the first time dynamic correlations, Onsager coefficients, Maxwell-Stefan (MS) diffusivities, and the concentration dependence of density and enthalpy of the molten salt mixture LiF-ThF4 at 1200 K in the composition range of 2-45% ThF4 and also at eutectic composition in the temperature range of 1123-1600 K using Green-Kubo formalism and equilibrium molecular dynamics simulations. We have observed an interesting oscillating pattern for the MS diffusivity for the cation-cation pair, in which ĐLi-Th oscillates between positive and negative values with the amplitude of the oscillation reducing as the system becomes rich in ThF4. Through the velocity autocorrelation function, vibrational density of states, radial distribution function analysis, and structural snapshots, we establish an interplay between the local structure and multicomponent dynamics and predict that formation of negatively charged [ThFn](4-n) clusters at a higher ThF4 mole % makes positively charged Li(+) ions oscillate between different clusters, with their range of motion reducing as the number of [ThFn](4-n) clusters increases, and finally Li(+) ions almost get trapped at a higher ThF4% when the electrostatic force on Li(+) exerted by various surrounding clusters gets balanced. Although reports on variations of density and enthalpy with temperature exist in the literature, for the first time we report variations of the density and enthalpy of LiF-ThF4 with the concentration of ThF4 (mole %) and fit them with the square root function of ThF4 concentration, which will be very useful for experimentalists to obtain data over a range of concentrations from fitting the formula for design purposes. The formation of [ThFn](4-n) clusters and the reduction in the diffusivity of the ions at a higher ThF4% may limit the

  11. Effect of zwitterionic salt on the electrochemical properties of a solid polymer electrolyte with high temperature stability for lithium ion batteries

    Energy Technology Data Exchange (ETDEWEB)

    Li, Z.H., E-mail: lzh69@xtu.edu.c [Key Laboratory of Environmentally Friendly Chemistry and Applications of Ministry of Education, College of Chemistry, Xiangtan University, Hunan 411105 (China); Xia, Q.L.; Liu, L.L.; Lei, G.T.; Xiao, Q.Z.; Gao, D.S. [Key Laboratory of Environmentally Friendly Chemistry and Applications of Ministry of Education, College of Chemistry, Xiangtan University, Hunan 411105 (China); Zhou, X.D. [State Key Laboratory of Chemical Engineering, East China University of Science and Technology, Shanghai 200237 (China)

    2010-12-30

    In this study, we prepare a kind of solid polymer electrolyte (SPE) based on N-ethyl-N'-methyl imidazolium tetrafluoroborate (EMIBF{sub 4}), LiBF{sub 4} and poly(vinylidene difluoride-co-hexafluoropropylene) [P(VdF-HFP)] copolymer. The resultant SPE displays high thermal stability above 300 {sup o}C and high room temperature ionic conductivity near to 10{sup -3} S cm{sup -1}. Its electrochemical properties are improved with incorporation of a zwitterionic salt 1-(1-methyl-3-imidazolium)propane-3-sulfonate (MIm3S). When the SPE contains 1.0 wt% of the MIm3S, it has a high ionic conductivity of 1.57 x 10{sup -3} S cm{sup -1} at room temperature, the maximum lithium ions transference number of 0.36 and the minimum apparent activation energy for ions transportation of 30.9 kJ mol{sup -1}. The charge-discharge performance of a Li{sub 4}Ti{sub 5}O{sub 12}/SPE/LiCoO{sub 2} cell indicates the potential application of the as-prepared SPE in lithium ion batteries.

  12. Matrix-elimination with steam distillation for determination of short-chain fatty acids in hypersaline waters from pre-salt layer by ion-exclusion chromatography.

    Science.gov (United States)

    Ferreira, Fernanda N; Carneiro, Manuel C; Vaitsman, Delmo S; Pontes, Fernanda V M; Monteiro, Maria Inês C; Silva, Lílian Irene D da; Neto, Arnaldo Alcover

    2012-02-03

    A method for determination of formic, acetic, propionic and butyric acids in hypersaline waters by ion-exclusion chromatography (IEC), using steam distillation to eliminate matrix-interference, was developed. The steam distillation variables such as type of solution to collect the distillate, distillation time and volume of the 50% v/v H₂SO₄ solution were optimized. The effect of the addition of NaCl different concentrations to the calibration standards on the carboxylic acid recovery was also investigated. Detection limits of 0.2, 0.5, 0.3 and 1.5 mg L⁻¹ were obtained for formic, acetic, propionic and butyric acids, respectively. Produced waters from petroleum reservoirs in the Brazilian pre-salt layer containing about 19% m/v of NaCl were analyzed. Good recoveries (99-108%) were obtained for all acids in spiked produced water samples.

  13. Temperature dependence of corrosion inhibition of steels used in oil well stimulation using acetylenic compound and halide ion salt mixtures

    Energy Technology Data Exchange (ETDEWEB)

    Menezes, M.A.M. [Universidade Federal do Rio de Janeiro (UFRJ), RJ (Brazil). Escola de Quimica], E-mail: marcom@eq.ufrj.br; Valle, M.L.M. [Universidade Federal do Rio de Janeiro (UFRJ), RJ (Brazil). Escola de Quimica. Dept. de Processos Organicos; Dweck, J. [Universidade Federal do Rio de Janeiro (UFRJ), RJ (Brazil). Escola de Quimica. Dept. de Processos Inorganicos; Queiroz Neto, J.C. [Petroleo Brasileiro S.A. (CENPES / PETROBRAS), Rio de Janeiro, RJ (Brazil). Centro de Pesquisas

    2007-07-15

    Halogenated salt (HS)-acetylenic compound (AC) mixtures were tested as corrosion inhibitors of 13Cr and 22Cr stainless steel and N80 and P110 carbon steel when exposed to 15 wt.% HCl solutions, at 50 deg C, 80 deg C and 100 deg C. The best corrosion inhibition efficiency is obtained when the concentration of both AC and HS is 1.5 wt. %, which indicates the use of all tested steels in oil well stimulation operated at 50 deg C and the use of 13Cr, N80 and P110 steels in oil well processing temperatures up to 100 deg C. (author)

  14. Principal Locations of Major-Ion, Trace-Element, Nitrate, and Escherichia coli Loading to Emigration Creek, Salt Lake County, Utah, October 2005

    Science.gov (United States)

    Kimball, Briant A.; Runkel, Robert L.; Walton-Day, Katherine

    2008-01-01

    Housing development and recreational activity in Emigration Canyon have increased substantially since 1980, perhaps causing an observed decrease in water quality of this northern Utah stream located near Salt Lake City. To identify reaches of the stream that contribute to water-quality degradation, a tracer-injection and synoptic-sampling study was done to quantify mass loading of major ions, trace elements, nitrate, and Escherichia coli (E. coli) to the stream. The resulting mass-loading profiles for major ions and trace elements indicate both geologic and anthropogenic inputs to the stream, principally from tributary and spring inflows to the stream at Brigham Fork, Burr Fork, Wagner Spring, Emigration Tunnel Spring, Blacksmith Hollow, and Killyon Canyon. The pattern of nitrate loading does not correspond to the major-ion and trace-element loading patterns. Nitrate levels in the stream did not exceed water-quality standards at the time of synoptic sampling. The majority of nitrate mass loading can be considered related to anthropogenic input, based on the field settings and trends in stable isotope ratios of nitrogen. The pattern of E. coli loading does not correspond to the major-ion, trace-element, or nitrate loading patterns. The majority of E. coli loading was related to anthropogenic sources based on field setting, but a considerable part of the loading also comes from possible animal sources in Killyon Canyon, in Perkins Flat, and in Rotary Park. In this late summer sampling, E. coli concentrations only exceeded water-quality standards in limited sections of the study reach. The mass-loading approach used in this study provides a means to design future studies and to evaluate the loading on a catchment scale.

  15. The influence of salt type on the retention of bovine serum albumin in ion-exchange chromatography

    DEFF Research Database (Denmark)

    Al-Jibbouri, Sattar

    2007-01-01

    that the mechanism of protein retention in ion-exchange chromatography (IEC) involves interactions between the protein solute, the mobile phase constituents and the stationary phase. The effect of protein activity coefficient in the mobile phase on the protein retention volumes is verified....

  16. Asymmetric Ashes

    Science.gov (United States)

    2006-11-01

    that oscillate in certain directions. Reflection or scattering of light favours certain orientations of the electric and magnetic fields over others. This is why polarising sunglasses can filter out the glint of sunlight reflected off a pond. When light scatters through the expanding debris of a supernova, it retains information about the orientation of the scattering layers. If the supernova is spherically symmetric, all orientations will be present equally and will average out, so there will be no net polarisation. If, however, the gas shell is not round, a slight net polarisation will be imprinted on the light. This is what broad-band polarimetry can accomplish. If additional spectral information is available ('spectro-polarimetry'), one can determine whether the asymmetry is in the continuum light or in some spectral lines. In the case of the Type Ia supernovae, the astronomers found that the continuum polarisation is very small so that the overall shape of the explosion is crudely spherical. But the much larger polarization in strongly blue-shifted spectral lines evidences the presence, in the outer regions, of fast moving clumps with peculiar chemical composition. "Our study reveals that explosions of Type Ia supernovae are really three-dimensional phenomena," says Dietrich Baade. "The outer regions of the blast cloud is asymmetric, with different materials found in 'clumps', while the inner regions are smooth." "This study was possible because polarimetry could unfold its full strength thanks to the light-collecting power of the Very Large Telescope and the very precise calibration of the FORS instrument," he adds. The research team first spotted this asymmetry in 2003, as part of the same observational campaign (ESO PR 23/03 and ESO PR Photo 26/05). The new, more extensive results show that the degree of polarisation and, hence, the asphericity, correlates with the intrinsic brightness of the explosion. The brighter the supernova, the smoother, or less clumpy

  17. Liquid-liquid extraction of ion-association complexes of cobalt(II-4-(2-pyridylazoresorcinol with ditetrazolium salts

    Directory of Open Access Journals (Sweden)

    Divarova Vidka V.

    2015-01-01

    Full Text Available The formation and liquid-liquid extraction of ion-association complexes between Co(II-4-(2-Pyridylazoresorcinol (PAR anionic chelates and cations of three ditetrazolium chlorides were studied: Blue Tetrazolium chloride (BTC, Neotetrazolium chloride (NTC and Nitro Blue Tetrazolium chloride (NBT. The optimum conditions for the formation and solvent extraction of the ion-association comlpex chelates were determined. It has been found that in the systems of Co(II-PAR-DTS, the reactants are reacted in molar ratios 1:2:1 and the general formula of complexes was suggested. The extraction equilibria were investigated and quantitatively characterized by the equilibrium constants and the recovery factors. The analytical characteristics of the complexes were calculated.

  18. Plausible molecular and crystal structures of chitosan/HI type II salt.

    Science.gov (United States)

    Lertworasirikul, Amornrat; Noguchi, Keiichi; Ogawa, Kozo; Okuyama, Kenji

    2004-03-15

    Chitosan/HI type II salt prepared from crab tendon was investigated by X-ray fiber diffraction. Two polymer chains and 16 iodide ions (I(-)) crystallized in a tetragonal unit cell with lattice parameters of a = b = 10.68(3), c (fiber axis) = 40.77(13) A, and a space group P4(1). Chitosan forms a fourfold helix with a 40.77 A fiber period having a disaccharide as the helical asymmetric unit. One of the O-3... O-5 intramolecular hydrogen bonds at the glycosidic linkage is weakened by interacting with iodide ions, which seems to cause the polymer to take the 4/1-helical symmetry rather than the extended 2/1-helix. The plausible orientations of two O-6 atoms in the helical asymmetric unit were found to be gt and gg. Two chains are running through at the corner and the center of the unit cell along the c-axis. They are linked by hydrogen bonds between N-21 and O-61 atoms. Two out of four independent iodide ions are packed between the corner chains while the other two are packed between the corner and center chains when viewing through the ab-plane. The crystal structure of the salt is stabilized by hydrogen bonds between these iodide ions and N-21, N-22, O-32, O-61, O-62 of the polymer chains.

  19. Salt Tolerance in Soybean

    Institute of Scientific and Technical Information of China (English)

    Tsui-Hung Phang; Guihua Shao; Hon-Ming Lam

    2008-01-01

    Soybean is an Important cash crop and its productivity is significantly hampered by salt stress. High salt Imposes negative impacts on growth, nodulation, agronomy traits, seed quality and quantity, and thus reduces the yield of soybean. To cope with salt stress, soybean has developed several tolerance mechanisms, including: (I) maintenance of ion homeostasis; (ii) adjustment in response to osmotic stress; (iii) restoration of osmotic balance; and (iv) other metabolic and structural adaptations. The regulatory network for abiotic stress responses in higher plants has been studied extensively in model plants such as Arabidopsis thaliana. Some homologous components involved in salt stress responses have been identified in soybean. In this review, we tried to integrate the relevant works on soybean and proposes a working model to descdbe Its salt stress responses at the molecular level.

  20. Physiological mechanisms for high salt tolerance in wild soybean (Glycine soja from Yellow River Delta, China: photosynthesis, osmotic regulation, ion flux and antioxidant capacity.

    Directory of Open Access Journals (Sweden)

    Peng Chen

    Full Text Available Glycine soja (BB52 is a wild soybean cultivar grown in coastal saline land in Yellow River Delta, China. In order to reveal the physiological mechanisms adapting to salinity, we examined photosynthesis, ion flux, antioxidant system and water status in Glycine soja under NaCl treatments, taking a cultivated soybean, ZH13, as control. Upon NaCl exposure, higher relative water content and water potential were maintained in the leaf of BB52 than ZH13, which might depend on the more accumulation of osmotic substances such as glycinebetaine and proline. Compared with ZH13, activities of antioxidant enzymes including superoxide dismutase, catalase, ascorbate peroxidase and contents of ascorbate, glutathione and phenolics were enhanced to a higher level in BB52 leaf under NaCl stress, which could mitigate the salt-induced oxidative damage in BB52. Consistently, lipid peroxidation indicated by malondialdehyde content was lower in BB52 leaf. Photosynthetic rate (Pn was decreased by NaCl stress in BB52 and ZH13, and the decrease was greater in ZH13. The decreased Pn in BB52 was mainly due to stomatal limitation. The inhibited activation of rubisco enzyme in ZH13 due to the decrease of rubisco activase content became an important limiting factor of Pn, when NaCl concentration increased to 200 mM. Rubisco activase in BB52 was not affected by NaCl stress. Less negative impact in BB52 derived from lower contents of Na(+ and Cl(- in the tissues, and non-invasive micro-test technique revealed that BB52 roots had higher ability to extrude Na(+ and Cl(-. Wild soybean is a valuable genetic resource, and our study may provide a reference for molecular biologist to improve the salt tolerance of cultivated soybean in face of farmland salinity.

  1. Physiological mechanisms for high salt tolerance in wild soybean (Glycine soja) from Yellow River Delta, China: photosynthesis, osmotic regulation, ion flux and antioxidant capacity.

    Science.gov (United States)

    Chen, Peng; Yan, Kun; Shao, Hongbo; Zhao, Shijie

    2013-01-01

    Glycine soja (BB52) is a wild soybean cultivar grown in coastal saline land in Yellow River Delta, China. In order to reveal the physiological mechanisms adapting to salinity, we examined photosynthesis, ion flux, antioxidant system and water status in Glycine soja under NaCl treatments, taking a cultivated soybean, ZH13, as control. Upon NaCl exposure, higher relative water content and water potential were maintained in the leaf of BB52 than ZH13, which might depend on the more accumulation of osmotic substances such as glycinebetaine and proline. Compared with ZH13, activities of antioxidant enzymes including superoxide dismutase, catalase, ascorbate peroxidase and contents of ascorbate, glutathione and phenolics were enhanced to a higher level in BB52 leaf under NaCl stress, which could mitigate the salt-induced oxidative damage in BB52. Consistently, lipid peroxidation indicated by malondialdehyde content was lower in BB52 leaf. Photosynthetic rate (Pn) was decreased by NaCl stress in BB52 and ZH13, and the decrease was greater in ZH13. The decreased Pn in BB52 was mainly due to stomatal limitation. The inhibited activation of rubisco enzyme in ZH13 due to the decrease of rubisco activase content became an important limiting factor of Pn, when NaCl concentration increased to 200 mM. Rubisco activase in BB52 was not affected by NaCl stress. Less negative impact in BB52 derived from lower contents of Na(+) and Cl(-) in the tissues, and non-invasive micro-test technique revealed that BB52 roots had higher ability to extrude Na(+) and Cl(-). Wild soybean is a valuable genetic resource, and our study may provide a reference for molecular biologist to improve the salt tolerance of cultivated soybean in face of farmland salinity.

  2. Halotolerant cyanobacterium Aphanothece halophytica contains NapA-type Na+/H+ antiporters with novel ion specificity that are involved in salt tolerance at alkaline pH.

    Science.gov (United States)

    Wutipraditkul, Nuchanat; Waditee, Rungaroon; Incharoensakdi, Aran; Hibino, Takashi; Tanaka, Yoshito; Nakamura, Tatsunosuke; Shikata, Masamitsu; Takabe, Tetsuko; Takabe, Teruhiro

    2005-08-01

    Aphanothece halophytica is a halotolerant alkaliphilic cyanobacterium which can grow at NaCl concentrations up to 3.0 M and at pH values up to 11. The genome sequence revealed that the cyanobacterium Synechocystis sp. strain PCC 6803 contains five putative Na+/H+ antiporters, two of which are homologous to NhaP of Pseudomonas aeruginosa and three of which are homologous to NapA of Enterococcus hirae. The physiological and functional properties of NapA-type antiporters are largely unknown. One of NapA-type antiporters in Synechocystis sp. strain PCC 6803 has been proposed to be essential for the survival of this organism. In this study, we examined the isolation and characterization of the homologous gene in Aphanothece halophytica. Two genes encoding polypeptides of the same size, designated Ap-napA1-1 and Ap-napA1-2, were isolated. Ap-NapA1-1 exhibited a higher level of homology to the Synechocystis ortholog (Syn-NapA1) than Ap-NapA1-2 exhibited. Ap-NapA1-1, Ap-NapA1-2, and Syn-NapA1 complemented the salt-sensitive phenotypes of an Escherichia coli mutant and exhibited strongly pH-dependent Na+/H+ and Li+/H+ exchange activities (the highest activities were at alkaline pH), although the activities of Ap-NapA1-2 were significantly lower than the activities of the other polypeptides. Only one these polypeptides, Ap-NapA1-2, complemented a K+ uptake-deficient E. coli mutant and exhibited K+ uptake activity. Mutagenesis experiments suggested the importance of Glu129, Asp225, and Asp226 in the putative transmembrane segment and Glu142 in the loop region for the activity. Overexpression of Ap-NapA1-1 in the freshwater cyanobacterium Synechococcus sp. strain PCC 7942 enhanced the salt tolerance of cells, especially at alkaline pH. These findings indicate that A. halophytica has two NapA1-type antiporters which exhibit different ion specificities and play an important role in salt tolerance at alkaline pH.

  3. Hydration and ion pair formation in common aqueous La(III) salt solutions--a Raman scattering and DFT study.

    Science.gov (United States)

    Rudolph, Wolfram W; Irmer, Gert

    2015-01-01

    Raman spectra of aqueous lanthanum perchlorate, triflate (trifluorosulfonate), chloride and nitrate solutions were measured over a broad concentration (0.121-3.050 mol L(-1)) range at room temperature (23 °C). A very weak mode at 343 cm(-1) with a full width at half height at 49 cm(-1) in the isotropic spectrum suggests that the nona-aqua La(III) ion is thermodynamically stable in dilute perchlorate solutions (∼0.2 mol L(-1)) while in concentrated perchlorate solutions outer-sphere ion pairs and contact ion pairs are formed. The La(3+) nona-hydrate was also detected in a 1.2 mol L(-1) La(CF3SO3)3(aq). In lanthanum chloride solutions chloro-complex formation was detected over the measured concentration range from 0.5-3.050 mol L(-1). The chloro-complexes in LaCl3(aq) are fairly weak and disappear with dilution. At a concentration complexes disappeared. In LaCl3 solutions, with additional HCl, a series of chloro-complexes of the type [La(OH2)(9-n)Cln](+3-n) (n = 1-3) were formed. The La(NO3)3(aq) spectra were compared with a spectrum of a 0.409 mol L(-1) NaNO3(aq) and it was concluded that in La(NO3)3(aq) over the concentration range from 0.121-1.844 mol L(-1), nitrato-complexes, [La(OH2)(9-n)(NO3)n](+3-n) (n = 1, 2) were formed. These nitrato-complexes are quite weak and disappear with dilution La(OH2)9](3+) with the polarizable dielectric continuum are in good agreement with data from recent structural experimental measurements and high quality simulations. The DFT frequency of the La-O stretching mode at 328.2 cm(-1), is only slightly smaller than the experimental one.

  4. Determination of the electrochemical performance and stability of the lithium-salt, lithium 4,5-dicyano-2-(trifluoromethyl) imidazolide, with various anodes in Li-ion cells

    Science.gov (United States)

    Paillet, Sabrina; Schmidt, Gregory; Ladouceur, Sébastien; Fréchette, Joël; Barray, Francis; Clément, Daniel; Hovington, Pierre; Guerfi, Abdelbast; Vijh, Ashok; Cayrefourcq, Ian; Zaghib, Karim

    2015-12-01

    The electrochemical performance and stability of lithium 4,5-dicyano-2-(trifluoromethyl) imidazolide (LiTDI), which is a promising lithium salt for electrolytes in lithium-ion batteries, are discussed. The power capability of LiTDI in EC/DEC (3/7 v/v) in half cells was evaluated with standard anodes used in the lithium-ion battery industry: graphite and Li4Ti5O12 (LTO). The effects of two additives, vinylene carbonate (VC) and fluoro-ethylene carbonate (FEC), were investigated (2% weight in EC/DEC) and compared with a reference electrolyte, 1 M LiPF6 (EC/DEC + 2%VC). LiTDI forms a thin SEI with FEC that is uniformly deposited on graphite, which allows high power capability with 93.9% of the specific capacity at 10C (92.3% for 1 M LiPF6 + 2%VC). Excellent results were also obtained for LiTDI with LTO, 91.1% of the specific capacity was recovered at 10C vs. 91.5% for LiPF6. The stability of LiTDI was evaluated in pouch-cells: LFP/LTO (1C-rate) and NMC/LTO (C/4-rate). The results show that the performance of LiTDI is comparable to that of LiPF6, 85.4% of the capacity was recovered after 900 cycles (87.6% for LiPF6) for LFP/LTO, and 85.8% of capacity was obtained after 450 cycles (86.3% for LiPF6) for NMC/LTO.

  5. Processing method for molten salt waste

    Energy Technology Data Exchange (ETDEWEB)

    Ito, Shuichi; Sawa, Toshio; Hoshikawa, Tadahiro; Suzuoki, Akira

    1999-01-06

    The present invention concerns a processing method for selectively adsorbing and removing radioactive metal ingredients contained in high temperature molten salts by an inorganic ion exchanger and separating radioactive metal ingredients from the molten salts as high level radioactive wastes upon reprocessing of spent nuclear fuels by using molten salts. The molten salts occluded in the inorganic ion exchanger are desorbed with highly purified water. Successively, saturation adsorbed radioactive metal ingredients are desorbed by an aqueous solution of alkali metal salt or an aqueous solution of alkaline earth metal salt. The desorbed molten salts and radioactive metal ingredients are formed into at least two kinds of radioactive waste solidification materials depending on each of radioactivity level. As the inorganic ion exchanger, at least one of aluminosilicate and hydroxides is used. Then, molten salt wastes generated upon a dry-type reprocessing can be processed as a stable borosilicate glass solidification material or as a similar homogeneous solid material. (T.M.)

  6. Growth and cellular ion content of a salt-sensitive symbiotic system Azolla pinnata-Anabaena azollae under NaCl stress.

    Science.gov (United States)

    Rai, Vandna; Sharma, Naveen Kumar; Rai, Ashwani K

    2006-09-01

    Salinity, at a concentration of 10 mM NaCl affected the growth of Azolla pinnata-Anabaena azollae association and became lethal at 40 mM. Plants exposed up to 30 mM NaCl exhibited longer roots than the control, especially during the beginning of incubation. Average root number in plants exposed to 10 and 20 mM NaCl remained almost the same as in control. A further rise in NaCl concentration to 30 mM reduced the root number, and roots shed off at 40 mM NaCl. Presence of NaCl in the nutrient solution increased the cellular Na+ of the intact association exhibiting differential accumulation by individual partners, while it reduced the cellular Ca2+ level. However, cellular K+ content did not show significant change. Cellular Na+ based on fresh weight of respective individual partners (host tissues and cyanobiont) remained higher in the host tissues than the cyanobiont, while reverse was true for K+ and Ca2+ contents. The contribution of A. azollae in the total cellular ion content of the association was a little because of meagre contribution of the cyanobiont mass (19-21%). High salt sensitivity of Azolla-Anabaena complex is due to an inability of the association to maintain low Na+ and high Ca2+ cellular level.

  7. Anion- interactions in layered structures of salts of 5-(hydroxyimino) quinolin-8-one and related salts

    Indian Academy of Sciences (India)

    Prithiviraj Khakhlary; Jubaraj B Baruah

    2015-01-01

    Relevance of anion- interactions in chloride, bromide, nitrate and perchlorate salts of 5-(hydroxyimino)quinolin-8-one are discussed. Structures of nitrate salt of 5-aminoquinoline as well as nitrate salt of 4-hydroxyquinazoline are compared with the structure of nitrate salt of 5-(hydroxyimino)quinolin-8-one. From such a comparison, two different arrangements of nitrate ions with respect to the respective cations are discerned. Nitrate ions are sandwiched between aromatic planes of cations in nitrate salts of 5-(hydroxyimino)quinolin-8-one or 4-hydroxyquinazoline; whereas, nitrate ions are in oblique positions with respect to aromatic planes of counter cations in nitrate salt of 5-aminoquinoline. Binding constants of different nitrate salts in solution are determined by UV-visible spectroscopic titrations. Solution study shows formation of ion-pairs of these salts in solution.

  8. Hydrogen sulfide is involved in maintaining ion homeostasis via regulating plasma membrane Na+/H+ antiporter system in the hydrogen peroxide-dependent manner in salt-stress Arabidopsis thaliana root.

    Science.gov (United States)

    Li, Jisheng; Jia, Honglei; Wang, Jue; Cao, Qianhua; Wen, Zichao

    2014-07-01

    Hydrogen sulfide (H2S) and hydrogen peroxide (H2O2) function as the signaling molecules in plants responding to salt stresses. The present study presents a signaling network involving H2S and H2O2 in salt resistance pathway of the Arabidopsis root. Arabidopsis roots were sensitive to 100 mM NaCl treatment, which displayed a great increase in electrolyte leakage (EL) and Na(+)/K(+) ratio under salt stress. The treatment of H2S donors sodium hydrosulfide (NaHS) enhanced the salt tolerance by maintaining a lower Na(+)/K(+) ratio. In addition, the inhibition of root growth under salt stress was removed by H2S. Further studies indicated that H2O2 was involved in H2S-induced salt tolerance pathway. H2S induced the production of the endogenous H2O2 via regulating the activities of glucose-6-phosphate dehydrogenase (G6PDH) and plasma membrane (PM) NADPH oxidase, with the treatment with dimethylthiourea (DMTU, an ROS scavenger), diphenylene iodonium (DPI, a PM NADPH oxidase inhibitor), or glycerol (G6PDH inhibitor) removing the effect of H2S. Treatment with amiloride (an inhibitor of PM Na(+)/H(+) antiporter) and vanadate (an inhibitor of PM H(+)-ATPase) also inhibited the activity of H2S on Na(+)/K(+) ratio. Through an analysis of quantitative real-time polymerase chain reaction and Western blot, we found that H2S promoted the genes expression and the phosphorylation level of PM H(+)-ATPase and Na(+)/H(+) antiporter protein level. However, when the endogenous H2O2 level was inhibited by DPI or DMTU, the effect of H2S on the PM Na(+)/H(+) antiporter system was removed. Taken together, H2S maintains ion homeostasis in the H2O2-dependent manner in salt-stress Arabidopsis root.

  9. 土壤盐胁迫降低后甜高粱的补偿生长和盐离子分布特征%The compensation growth and salt ion distribution in sweet sorghum (Sorghum bicolor L. Moench) after salt stress reduction

    Institute of Scientific and Technical Information of China (English)

    李春宏; 郭文琦; 张培通; 殷剑美; 韩晓勇; 王立

    2016-01-01

    Adversity compensation effect is ubiquity in crops, which impacts on crop growth, development and yield. To elucidate the compensation growth of sweet sorghum following soil salt stress reduction, a pot experiment was conducted, in which 5 g×kg-1 (high salt), 2 g×kg-1 down from 5 g×kg-1 (salt stress reduction) and 2 g×kg-1 (low-salt control) of soil salt treatments were applied at the elongation stage of sweet sorghum. Then growth rate of dry matter on aboveground parts (leaf, leaf sheath and stem) and aboveground dry matter at maturity of two cultivated sweet sorghum varieties were determined. The experiment also measured salt ions (K+, Na+ and Cl-) distribution in aboveground organs of sweet sorghum. The results showed that the growth rate of aboveground dry matter in high salt treatment was always significantly lower than that of control. There was clear acceleration of growth after soil salt reduction, and gradually exceeded the growth of control due to overcompensation effect. At maturity stage, both plant height and aboveground dry matter of two sorghum varieties decreased sharply in high salt treatment. They decreased by 7.69% and 33.21%, respectively, in ‘Liaotian 1’ in salt stress reduction treatment compared with the low-salt control, moreover, no obviously difference was found in both plant height and aboveground dry matter of ‘Zhongketian 3’ between salt stress reduction treatment and low-salt control. The contents of Na+and Cl-in aboveground organs significantly increased, and K+content slightly increased under high salt stressed condition. At 35 days after soil salt reduction, the contents of Na+ and Cl- still higher than that of low-salt control, but decreased significantly compared to that of high salt treatment. Although K+content in both leaf sheath and stem in soil salt reduction treatment were higher than that of low-salt control, no difference was observed in leaf. The results suggested that ion toxicity in salt-stressed sweet

  10. Novel binary deep eutectic electrolytes for rechargeable Li-ion batteries based on mixtures of alkyl sulfonamides and lithium perfluoroalkylsulfonimide salts

    Science.gov (United States)

    Geiculescu, O. E.; DesMarteau, D. D.; Creager, S. E.; Haik, O.; Hirshberg, D.; Shilina, Y.; Zinigrad, E.; Levi, M. D.; Aurbach, D.; Halalay, I. C.

    2016-03-01

    Ionic liquids (IL's) were proposed for use in Li-ion batteries (LIBs), in order to mitigate some of the well-known drawbacks of LiPF6/mixed organic carbonates solutions. However, their large cations seriously decrease lithium transference numbers and block lithium insertion sites at electrode-electrolyte interfaces, leading to poor LIB rate performance. Deep eutectic electrolytes (DEEs) (which share some of the advantages of ILs but possess only one cation, Li+), were then proposed, in order to overcome the difficulties associated with ILs. We report herein on the preparation, thermal properties (melting, crystallization, and glass transition temperatures), transport properties (specific conductivity and viscosity) and thermal stability of binary DEEs based on mixtures of lithium bis(trifluoromethane)sulfonimide or lithium bis(fluoro)sulfonimide salts with an alkyl sulfonamide solvent. Promise for LIB applications is demonstrated by chronoamperometry on Al current collectors, and cycling behavior of negative and positive electrodes. Residual current densities of 12 and 45 nA cm-2 were observed at 5 V vs. Li/Li+ on aluminum, 1.5 and 16 nA cm-2 at 4.5 V vs. Li/Li+, respectively for LiFSI and LiTFSI based DEEs. Capacities of 220, 130, and 175 mAh· g-1 were observed at low (C/13 or C/10) rates, respectively for petroleum coke, LiMn1/3Ni1/3Co1/3O2 (a.k.a. NMC 111) and LiAl0.05Co0.15Ni0.8O2 (a.k.a. NCA).

  11. Kinetic resolution of racemic carboxylic acids through asymmetric protolactonization promoted by chiral phosphonous acid diester.

    Science.gov (United States)

    Sakuma, Masayuki; Sakakura, Akira; Ishihara, Kazuaki

    2013-06-07

    Chiral phosphonium salts induce the kinetic resolution of racemic α-substituted unsaturated carboxylic acids through asymmetric protolactonization. Both the lactones and the recovered carboxylic acids are obtained with high enantioselectivities and high S (= kfast/kslow) values. Asymmetric protolactonization also leads to the desymmetrization of achiral carboxylic acids. Notably, chiral phosphonous acid diester not only induced the enantioselectivity but also promoted protolactonization.

  12. Crystal structures of five 1-alkyl-4-aryl-1,2,4-triazol-1-ium halide salts

    Directory of Open Access Journals (Sweden)

    Marites A. Guino-o

    2015-06-01

    Full Text Available The asymmetric units for the salts 4-(4-fluorophenyl-1-isopropyl-1,2,4-triazol-1-ium iodide, C11H13FN3+·I−, (1, 1-isopropyl-4-(4-methylphenyl-1,2,4-triazol-1-ium iodide, C12H16N3+·I−, (2, 1-isopropyl-4-phenyl-1,2,4-triazol-1-ium iodide, C11H14N3+·I−, (3, and 1-methyl-4-phenyl-1,2,4-triazol-1-ium iodide, C9H10N3+·I−, (4, contain one cation and one iodide ion, whereas in 1-benzyl-4-phenyl-1,2,4-triazol-1-ium bromide monohydrate, C15H14N3+·Br−·H2O, (5, there is an additional single water molecule. There is a predominant C—H...X(halide interaction for all salts, resulting in a two-dimensional extended sheet network between the triazolium cation and the halide ions. For salts with para-substitution on the aryl ring, there is an additional π–anion interaction between a triazolium carbon and iodide displayed by the layers. For salts without the para-substitution on the aryl ring, the π–π interactions are between the triazolium and aryl rings. The melting points of these salts agree with the predicted substituent inductive effects.

  13. Sessile multidroplets and salt droplets under high tangential electric fields

    Science.gov (United States)

    Xie, Guoxin; He, Feng; Liu, Xiang; Si, Lina; Guo, Dan

    2016-01-01

    Understanding the interaction behaviors between sessile droplets under imposed high voltages is very important in many practical situations, e.g., microfluidic devices and the degradation/aging problems of outdoor high-power applications. In the present work, the droplet coalescence, the discharge activity and the surface thermal distribution response between sessile multidroplets and chloride salt droplets under high tangential electric fields have been investigated with infrared thermography, high-speed photography and pulse current measurement. Obvious polarity effects on the discharge path direction and the temperature change in the droplets in the initial stage after discharge initiation were observed due to the anodic dissolution of metal ions from the electrode. In the case of sessile aligned multidroplets, the discharge path direction could affect the location of initial droplet coalescence. The smaller unmerged droplet would be drained into the merged large droplet as a result from the pressure difference inside the droplets rather than the asymmetric temperature change due to discharge. The discharge inception voltages and the temperature variations for two salt droplets closely correlated with the ionization degree of the salt, as well as the interfacial electrochemical reactions near the electrodes. Mechanisms of these observed phenomena were discussed. PMID:27121926

  14. Removal and separation of impurity ions in preparation of high-purity inorganic salts%高纯无机盐制备中杂质离子的去除与分离

    Institute of Scientific and Technical Information of China (English)

    石磊

    2012-01-01

    介绍了在制备高纯无机盐过程中,有害杂质离子——重有色金属离子(Cu、Mg、Zn、Pd、Cd等)、铁离子、砷化物的去除与分离方法:氧化-还原法、难溶金属氢氧化物沉淀法、硫化物沉淀法.%Introduced in the preparation of high purity inorganic salt process, harmful impurity ion-heavy non-ferrous metal ion (Cu,Mg,Zn,Pd,CDS,etc. ) ,iron ion,arsenide in removing and separation methods : oxidation-reduction method and difficult to thick metal hydroxide precipitation, sulfide precipitation.

  15. Synthesis, Characterization and Properties of Asymmetric Methide Anion Based Ionic Liquids Containing Nitrile Groups

    Institute of Scientific and Technical Information of China (English)

    ZOU Ting; LU Liang; LIU Xiu-Li; ZHANG Zhan; WANG Li-Bing; FU Xian-Lei; GAO Guo-Hua; KOU Yuan; HE Ming-Yuan

    2008-01-01

    A series of asymmetric methide anion based ionic liquids containing nitrile groups have been synthesized for the first time using the method of ion-exchange between sodium/potassium methide and various quaternary bro-mide/chloride salts of trimethylamine, triethylamine, tributylamine, N-methylpyrrolidine, and N-methylimidazole. All of the functionalised ionic liquids were characterized by IR, 1H, 13C NMR, MS and elemental analysis. The de-composition temperature of the ionic liquids measured via TGA ranged from 219 to 339 ℃. The functionalised ionic liquid, [Bmim][C(CN)2COCH3], was used as a ligand for Suzuki coupling reaction. The yields of the coupling reaction increased 10%-15% by the addition of the functionalised ionic liquid, [Bmim] [C(CN)2COCH3].

  16. Ion Colliders

    CERN Document Server

    Fischer, W

    2014-01-01

    High-energy ion colliders are large research tools in nuclear physics to study the Quark-Gluon-Plasma (QGP). The range of collision energy and high luminosity are important design and operational considerations. The experiments also expect flexibility with frequent changes in the collision energy, detector fields, and ion species. Ion species range from protons, including polarized protons in RHIC, to heavy nuclei like gold, lead and uranium. Asymmetric collision combinations (e.g. protons against heavy ions) are also essential. For the creation, acceleration, and storage of bright intense ion beams, limits are set by space charge, charge change, and intrabeam scattering effects, as well as beam losses due to a variety of other phenomena. Currently, there are two operating ion colliders, the Relativistic Heavy Ion Collider (RHIC) at BNL, and the Large Hadron Collider (LHC) at CERN.

  17. Synthesis and characterization of a new family of aryl-trifluoromethanesulfonylimide Li-Salts for Li-ion batteries and beyond

    Science.gov (United States)

    Ladouceur, Sébastien; Paillet, Sabrina; Vijh, Ashok; Guerfi, Abdelbast; Dontigny, Martin; Zaghib, Karim

    2015-10-01

    The battery energy-storage industry is evolving rapidly so new battery components are needed with high stability and improved energy density, as well as enhanced safety. In this paper, results on new salts, safer degradation and good electrochemical performances are reported. Four organic anions for Li-salts were synthesized and their conductivity, viscosity and electrochemical potential window in EC/DEC (3/7) solutions were examined. These salts have high thermal stability and safer degradation products (compared to LiPF6 and Li-TFSI), which were identified by TGA-MS. Cyclic voltammetry measurements showed their electrochemical window and oxidation limits were at least 4.3 and 4.5 V vs Li/Li+ using a platinum and high surface area carbon material working electrode, respectively. The salts passivated the common aluminum current collector at 4.4 V vs Li/Li+ and without corrosion. The properties of one Li salts were evaluated in half cell configuration as a model system using lithium iron phosphate (LFP), lithium titanate oxide (LTO) and graphite as electrodes. The performance of the salt showed promising behavior in the model system, compared to benchmark salts such as LiPF6 and Li-TFSI.

  18. Thomson scattering measurements from asymmetric interpenetrating plasma flows

    Energy Technology Data Exchange (ETDEWEB)

    Ross, J. S., E-mail: ross36@llnl.gov; Moody, J. D.; Fiuza, F.; Ryutov, D.; Divol, L.; Huntington, C. M.; Park, H.-S. [Lawrence Livermore National Laboratory, P.O. Box 808, Livermore, California 94551 (United States)

    2014-11-15

    Imaging Thomson scattering measurements of collective ion-acoustic fluctuations have been utilized to determine ion temperature and density from laser produced counter-streaming asymmetric flows. Two foils are heated with 8 laser beams each, 500 J per beam, at the Omega Laser facility. Measurements are made 4 mm from the foil surface using a 60 J 2ω probe laser with a 200 ps pulse length. Measuring the electron density and temperature from the electron-plasma fluctuations constrains the fit of the multi-ion species, asymmetric flows theoretical form factor for the ion feature such that the ion temperatures, ion densities, and flow velocities for each plasma flow are determined.

  19. Molecular biology of cyanobacterial salt acclimation.

    Science.gov (United States)

    Hagemann, Martin

    2011-01-01

    High and changing salt concentrations represent major abiotic factors limiting the growth of microorganisms. During their long evolution, cyanobacteria have adapted to aquatic habitats with various salt concentrations. High salt concentrations in the medium challenge the cell with reduced water availability and high contents of inorganic ions. The basic mechanism of salt acclimation involves the active extrusion of toxic inorganic ions and the accumulation of compatible solutes, including sucrose, trehalose, glucosylglycerol, and glycine betaine. The kinetics of these physiological processes has been exceptionally well studied in the model Synechocystis 6803, leading to the definition of five subsequent phases in reaching a new salt acclimation steady state. Recent '-omics' technologies using the advanced model Synechocystis 6803 have revealed a comprehensive picture of the dynamic process of salt acclimation involving the differential expression of hundreds of genes. However, the mechanisms involved in sensing specific salt stress signals are not well resolved. In the future, analysis of cyanobacterial salt acclimation will be directed toward defining the functions of the many unknown proteins upregulated in salt-stressed cells, identifying specific salt-sensing mechanisms, using salt-resistant strains of cyanobacteria for the production of bioenergy, and applying cyanobacterial stress genes to improve the salt tolerance of sensitive organisms.

  20. Salt splitting with ceramic membranes

    Energy Technology Data Exchange (ETDEWEB)

    Kurath, D. [Pacific Northwest National Lab., Richland, WA (United States)

    1996-10-01

    The purpose of this task is to develop ceramic membrane technologies for salt splitting of radioactively contaminated sodium salt solutions. This technology has the potential to reduce the low-level waste (LLW) disposal volume, the pH and sodium hydroxide content for subsequent processing steps, the sodium content of interstitial liquid in high-level waste (HLW) sludges, and provide sodium hydroxide free of aluminum for recycle within processing plants at the DOE complex. Potential deployment sites include Hanford, Savannah River, and Idaho National Engineering Laboratory (INEL). The technical approach consists of electrochemical separation of sodium ions from the salt solution using sodium (Na) Super Ion Conductors (NaSICON). As the name implies, sodium ions are transported rapidly through these ceramic crystals even at room temperatures.

  1. Electronic structure and electro-optical properties of ion radicals formed during the reduction of N, N'-dialkylsubstituted salts of 4,4'-bipyridyl

    Science.gov (United States)

    Zakirov, M. I.; Efimov, N. N.; Mel'nikov, P. V.; Nodova, E. L.; Minin, V. V.

    2013-08-01

    Symmetric N, N'-disubstituted salts of 4,4'-bipyridyl (viologens) are synthesized and described. It is shown by cyclic voltammetry that disubstituted salts of 4,4'-bipyridyl have a tendency toward reversible two-electron reduction. Normal first and second step oxidation-reduction potentials with respect to saturated silver chloride electrodes at various potential scan rates are found. The spectra of the high-resolution electron paramagnetic resonance of viologen cation radicals formed during the reduction of N, N'-disubstituted salts of 4,4'-bipyridyl are obtained and interpreted. It is established that the nature of substitutes and counterions in a viologen molecule considerably influences the distribution of its spin density, voltammetric curves, and electro-optical properties.

  2. Asymmetrical field emitter

    Science.gov (United States)

    Fleming, J.G.; Smith, B.K.

    1995-10-10

    A method is disclosed for providing a field emitter with an asymmetrical emitter structure having a very sharp tip in close proximity to its gate. One preferred embodiment of the present invention includes an asymmetrical emitter and a gate. The emitter having a tip and a side is coupled to a substrate. The gate is connected to a step in the substrate. The step has a top surface and a side wall that is substantially parallel to the side of the emitter. The tip of the emitter is in close proximity to the gate. The emitter is at an emitter potential, and the gate is at a gate potential such that with the two potentials at appropriate values, electrons are emitted from the emitter. In one embodiment, the gate is separated from the emitter by an oxide layer, and the emitter is etched anisotropically to form its tip and its asymmetrical structure. 17 figs.

  3. Salt cookbook

    CERN Document Server

    Saha, Anirban

    2015-01-01

    If you are a professional associated with system and infrastructure management, looking at automated infrastructure and deployments, then this book is for you. No prior experience of Salt is required.

  4. Phosphate salts

    Science.gov (United States)

    ... levels that are too high, and for preventing kidney stones. They are also taken for treating osteomalacia (often ... But intravenous phosphate salts should not be used. Kidney stones (nephrolithiasis). Taking potassium phosphate by mouth might help ...

  5. Gene Expression, Protein Function and Pathways of Arabidopsis thaliana Responding to Silver Nanoparticles in Comparison to Silver Ions, Cold, Salt, Drought, and Heat

    Directory of Open Access Journals (Sweden)

    Eisa Kohan-Baghkheirati

    2015-03-01

    Full Text Available Silver nanoparticles (AgNPs have been widely used in industry due to their unique physical and chemical properties. However, AgNPs have caused environmental concerns. To understand the risks of AgNPs, Arabidopsis microarray data for AgNP, Ag+, cold, salt, heat and drought stresses were analyzed. Up- and down-regulated genes of more than two-fold expression change were compared, while the encoded proteins of shared and unique genes between stresses were subjected to differential enrichment analyses. AgNPs affected the fewest genes (575 in the Arabidopsis genome, followed by Ag+ (1010, heat (1374, drought (1435, salt (4133 and cold (6536. More genes were up-regulated than down-regulated in AgNPs and Ag+ (438 and 780, respectively while cold down-regulated the most genes (4022. Responses to AgNPs were more similar to those of Ag+ (464 shared genes, cold (202, and salt (163 than to drought (50 or heat (30; the genes in the first four stresses were enriched with 32 PFAM domains and 44 InterPro protein classes. Moreover, 111 genes were unique in AgNPs and they were enriched in three biological functions: response to fungal infection, anion transport, and cell wall/plasma membrane related. Despite shared similarity to Ag+, cold and salt stresses, AgNPs are a new stressor to Arabidopsis.

  6. Asymmetrical international attitudes

    NARCIS (Netherlands)

    Van Oudenhoven, JP; Askevis-Leherpeux, F; Hannover, B; Jaarsma, R; Dardenne, B

    2002-01-01

    In general, attitudes towards nations have a fair amount of reciprocity: nations either like each other are relatively indifferent to each other or dislike each other Sometimes, however international attitudes are asymmetrical. In this study, we use social identity theory in order to explain asymmet

  7. Asymmetric reactions in continuous flow

    Directory of Open Access Journals (Sweden)

    Xiao Yin Mak

    2009-04-01

    Full Text Available An overview of asymmetric synthesis in continuous flow and microreactors is presented in this review. Applications of homogeneous and heterogeneous asymmetric catalysis as well as biocatalysis in flow are discussed.

  8. Asymmetric catalysis with helical polymers

    NARCIS (Netherlands)

    Megens, Rik P.; Roelfes, Gerard

    2011-01-01

    Inspired by nature, the use of helical biopolymer catalysts has emerged over the last years as a new approach to asymmetric catalysis. In this Concept article the various approaches and designs and their application in asymmetric catalysis will be discussed.

  9. Asymmetric Capacitance Behavior Based on the Relationship between Ion Dimension and Pore Size%基于离子尺寸与孔径关系的不对称电容行为

    Institute of Scientific and Technical Information of China (English)

    孙刚伟; 宋文华; 刘小军; 乔文明; 凌立成

    2011-01-01

    采用具有不同孔径分布的活性炭作为电极材料,研究了离子尺寸与孔结构对电容性能的影响.结果表明,正负极表现出不对称的电容行为,正负极的质量比电容分别为113和7 F·g-1.在负极电位区间,循环伏安曲线的响应电流明显减小.材料表面最大电荷存储量的理论计算与实验结果有着很好的一致性,这些结果表明用于阳离子电荷存储的电极孔隙空间不够发达,导致电容器在充电过程中负极材料表面达到电荷饱和状态,进而表现出较差的电容行为,然而,四氟硼酸根阴离子可以进入到正极电极材料大多数孔道中,电极未发生电荷饱和效应,表现出优异的电容行为,负极较低的比电容将会影响电容器的整体性能,因此,正负极应当根据离子尺寸与电极材料孔结构的构效关系进行匹配,以使电容器的比电容最大化.%We reported on the capacitive behaviors regarding to the relationship between ion size and pore architecture,using activated carbons with an adjusted pore structure as electrode materials.The results revealed that an asymmetric capacitance response occurred in both electrodes.The gravimetric capacitances for the positive and negative electrodes were 113 and 7 F.g-1,respectively.A significant current decay was presented in the negative region of cyclic voltammetry curve.Experimental and calculated maximum storage charges had a good agreement.This results suggested that the insufficiently developed pore architecture for cation accommodation led to a saturation effect on the active surface,consequently,a deteriorated capacitive performance in the negative electrode.Contrarily,when pore size was larger than tetrafluoroborate dimension,the saturation effect was not found.However,this was at the expense of the lower specific area capacitance in the positive electrode.The poor capacitive behavior of the negative electrode would limit the usable voltage of the cell system and

  10. 含咪唑环不对称双季铵盐的合成及缓蚀性能研究%synthesis and corrosion inhibition performance of the asymmetric bis Quaternary ammonium salt containinG imidaZole rinG

    Institute of Scientific and Technical Information of China (English)

    余宗学; 梁灵; 何毅; 马瑜; 李飞; 陈映晓

    2014-01-01

    成功合成了含咪唑环不对称双季铵盐,通过失重法、电化学阻抗谱、动电位扫描极化曲线、扫描电镜对合成产物在3% NaCl的饱和二氧化碳溶液中的缓蚀效率进行研究。结果表明,其在饱和二氧化碳溶液中对钢铁有着良好的缓蚀作用,缓蚀效率接近90%;运用Langmuir吸附等温式对吸附行为进行了拟合,表明其吸附类型符合Lang-muir吸附模型,吸附方式为化学吸附。%The asymmetric bis quaternary ammonium salt containing imidazole ring was synthesised suc-cessfully. And weight-loss method,electrochemical impedance spectroscopy,potentiodynamic polarization curve,scanning electron microscopy was used to study on the inhibition efficiency of this product in sodi-um chloride solutions(3. 00%)bubbled with CO2-saturated. The result shows that it has good corrosion inhibition for the P110 steel in this solution,and the corrosion inhibition efficiency is closed to 90%. The adsorption behavior was fitted using the Langmuir adsorption isotherm,and showed that the adsorption type conforms to the Langmuir adsorption isotherm,its adsorption mode is chemical adsorption.

  11. Two different molecular conformations found in chitosan type II salts.

    Science.gov (United States)

    Lertworasirikul, Amornrat; Tsue, Shin-ichiro; Noguchi, Keiichi; Okuyama, Kenji; Ogawa, Kozo

    2003-05-23

    The type II structure of chitosan acidic salts prepared from crab tendon in solid state was studied using an X-ray fiber diffraction technique together with the linked-atom least-squares (LALS) technique. The cylindrical Patterson method was applied to confirm the molecular conformation of the chitosan. It was shown that there are two different helical conformations for type II salts. One is the relaxed twofold helix having a tetrasaccharide as an asymmetric unit as found in chitosan.HCl salt, which was previously reported as a conformation of chitosan.HCOOH salt. The other is the fourfold helix having a disaccharide as an asymmetric unit newly found in chitosan.HI salt.

  12. Effect of iron salt counter ion in dose-response curves for inactivation of Fusarium solani in water through solar driven Fenton-like processes

    Science.gov (United States)

    Aurioles-López, Verónica; Polo-López, M. Inmaculada; Fernández-Ibáñez, Pilar; López-Malo, Aurelio; Bandala, Erick R.

    2016-02-01

    The inactivation of Fusarium solani in water was assessed by solar driven Fenton-like processes using three different iron salts: ferric acetylacetonate (Fe(acac)3), ferric chloride (FeCl3) and ferrous sulfate (FeSO4). The experimental conditions tested were [Fe] ≈ 5 mg L-1, [H2O2] ≈ 10 mg L-1 and [Fe] ≈ 10 mg L-1; [H2O2] ≈ 20 mg L-1 mild and high, respectively, and pH 3.0 and 5.0, under solar radiation. The highest inactivation rates were observed at high reaction conditions for the three iron salts tested at pH 5.0 with less than 3.0 kJ L-1 of accumulate energy (QUV) to achieve over 99.9% of F. solani inactivation. Fe(acac)3 was the best iron salt to accomplishing F. solani inactivation. The modified Fermi equation was used to fix the experimental inactivation, data showed it was helpful for modeling the process, adequately describing dose-response curves. Inactivation process using FeSO4 at pH 3.0 was modeled fairly with r2 = 0.98 and 0.99 (mild and high concentration, respectively). Fe(acac)3, FeCl3 and FeSO4 at high concentration (i.e. [Fe] ≈ 10 mg L-1; [H2O2] ≈ 20 mg L-1) and pH 5.0 showed the highest fitting values (r2 = 0.99). Iron salt type showed a remarkable influence on the Fenton-like inactivation process.

  13. Crystal structure of the heptamolybdate(VI) (paramolybdate) ion, [Mo7O24]6-, in the ammonium and potassium tetrahydrate salts

    Science.gov (United States)

    Evans, H.T.; Gatehouse, B.M.; Leverett, P.

    1975-01-01

    The crystal structures of the isomorphous salts MI6 [Mo7O24],4H2O (M = NH4 or K) have been refined by three-dimensional X-ray diffraction methods. Unit cell dimensions of these monoclinic compounds, space group P21/C with Z = 4, are, ammonium salt: a = 8.3934 ?? 0.0008, b = 36.1703 ?? 0.0045, c = 10.4715 ?? 0.0011 A??, ?? = 115.958?? ?? 0.008??; and potassium salt: a = 8.15 ?? 0.02, b = 35.68 ?? 0.1, c = 10.30 ?? 0.02 A??, ?? = 115.2?? ?? 02??. By use of multiple Weissenberg patterns, 8197 intensity data (Mo-K?? radiation) for the ammonium compound and 2178 (Cu-K?? radiation) for the potassium compound were estimated visually and used to test and refine Lindqvist's proposed structure in the space group P21/c. Lindqvist's structure was confirmed and the full matrix least-squares isotropic refinement led to R 0.076 (ammonium) 0.120 (potassium), with direct unambiguous location of the cations and water molecules in the potassium compound.

  14. Studies on the biofilm produced by Pseudomonas aeruginosa grown in different metal fatty acid salt media and its application in biodegradation of fatty acids and bioremediation of heavy metal ions.

    Science.gov (United States)

    Abinaya Sindu, P; Gautam, Pennathur

    2017-01-01

    Metal fatty acid salts (MFAS) in untreated industrial effluents cause environmental pollution. The use of biocompatible agents for remediation may help in reducing the harm caused to the ambient aquatic organism. Pseudomonas aeruginosa is a ubiquitous organism that thrives under harsh conditions and is resistant to toxic metal ions. The present study shows a proof-of-concept of using this organism in the biodegradation of MFAS. MFAS were prepared and we studied their effect on the growth of the planktonic form and the formation of biofilm by P. aeruginosa. We observed biofilm formation in the presence of all the MFAS when used as the sole carbon source, albeit the quantity of biofilm formed in the presence of cadmium and copper was less. There was no effect on the planktonic form of the organism but the formation of biofilm increased in the presence of magnesium palmitate. This study shows that metal ions play a pivotal role in the formation of biofilm. HPLC (high-performance liquid chromatography) analysis of the biofilm polysaccharide showed that hexose sugar was a major component when compared with pentose sugar. The structure of biofilm polysaccharide and the coordination of the metal ion with the biofilm polysaccharide were confirmed by FTIR (Fourier transform infrared spectroscopy) and Raman spectroscopy.

  15. Salt effects in electromembrane extraction

    DEFF Research Database (Denmark)

    Seip, Knut Fredrik; Jensen, Henrik; Kieu, Thanh Elisabeth

    2014-01-01

    Electromembrane extraction (EME) was performed on samples containing substantial amounts of NaCl to investigate how the presence of salts affected the recovery, repeatability, and membrane current in the extraction system. A group of 17 non-polar basic drugs with various physical chemical...... this loss and the physical chemical properties of these substances was seen. The recovery loss was hypothesized to be caused by ion pairing in the SLM, and a mathematical model for the extraction recovery in the presence of salts was made according to the experimental observations. Some variations...... to the EME system reduced this recovery loss, such as changing the SLM solvent from NPOE to 6-undecanone, or by using a different EME setup with more favorable volume ratios. This was in line with the ion pairing hypothesis and the mathematical model. This thorough investigation of how salts affect EME...

  16. Asymmetric information and economics

    Science.gov (United States)

    Frieden, B. Roy; Hawkins, Raymond J.

    2010-01-01

    We present an expression of the economic concept of asymmetric information with which it is possible to derive the dynamical laws of an economy. To illustrate the utility of this approach we show how the assumption of optimal information flow leads to a general class of investment strategies including the well-known Q theory of Tobin. Novel consequences of this formalism include a natural definition of market efficiency and an uncertainty principle relating capital stock and investment flow.

  17. Asymmetric extractions in orthodontics

    OpenAIRE

    Camilo Aquino Melgaço; Mônica Tirre de Souza Araújo

    2012-01-01

    INTRODUCTION: Extraction decisions are extremely important in during treatment planning. In addition to the extraction decision orthodontists have to choose what tooth should be extracted for the best solution of the problem and the esthetic/functional benefit of the patient. OBJECTIVE: This article aims at reviewing the literature relating the advantages, disadvantages and clinical implications of asymmetric extractions to orthodontics. METHODS: Keywords were selected in English and Portugue...

  18. Asymmetric Evolutionary Games.

    Directory of Open Access Journals (Sweden)

    Alex McAvoy

    2015-08-01

    Full Text Available Evolutionary game theory is a powerful framework for studying evolution in populations of interacting individuals. A common assumption in evolutionary game theory is that interactions are symmetric, which means that the players are distinguished by only their strategies. In nature, however, the microscopic interactions between players are nearly always asymmetric due to environmental effects, differing baseline characteristics, and other possible sources of heterogeneity. To model these phenomena, we introduce into evolutionary game theory two broad classes of asymmetric interactions: ecological and genotypic. Ecological asymmetry results from variation in the environments of the players, while genotypic asymmetry is a consequence of the players having differing baseline genotypes. We develop a theory of these forms of asymmetry for games in structured populations and use the classical social dilemmas, the Prisoner's Dilemma and the Snowdrift Game, for illustrations. Interestingly, asymmetric games reveal essential differences between models of genetic evolution based on reproduction and models of cultural evolution based on imitation that are not apparent in symmetric games.

  19. Asymmetric extractions in orthodontics

    Directory of Open Access Journals (Sweden)

    Camilo Aquino Melgaço

    2012-04-01

    Full Text Available INTRODUCTION: Extraction decisions are extremely important in during treatment planning. In addition to the extraction decision orthodontists have to choose what tooth should be extracted for the best solution of the problem and the esthetic/functional benefit of the patient. OBJECTIVE: This article aims at reviewing the literature relating the advantages, disadvantages and clinical implications of asymmetric extractions to orthodontics. METHODS: Keywords were selected in English and Portuguese and the EndNote 9 program was used for data base search in PubMed, Web of Science (WSc and LILACS. The selected articles were case reports, original articles and prospective or retrospective case-control studies concerning asymmetrical extractions of permanent teeth for the treatment of malocclusions. CONCLUSION: According to the literature reviewed asymmetric extractions can make some specific treatment mechanics easier. Cases finished with first permanent molars in Class II or III relationship in one or both sides seem not to cause esthetic or functional problems. However, diagnosis knowledge and mechanics control are essential for treatment success.

  20. 多种盐分离子作用下苋菜对重金属的吸收累积特征%Absorption and Accumulation of Heavy Metals in Amaranth Under Stress of Multiple Salt Ions

    Institute of Scientific and Technical Information of China (English)

    张乾坤; 刘亚男; 李取生; 石雷; 王立立

    2012-01-01

    Reference to the salt and heavy metals content in the pore water of tidal flat soil which was in different leaching and desalinization stages, a hydroponic experiment of amaranth was carried out to investigate absorption, accumulation and transportation of six heavy metals (Zn, Cu, Ni, Cr, Pb and Cd) by the plant under the combined effect of a variety of salts (SO42- , Cl- , NO3- , CO32- , Na+ , Ca2+ , K+ and Mg2 + , etc. ). Results show that compared with what was observed in the control, under the effects of salt ions different in concentration, the content of Cd in stems and leaves of the plant increased by 69. 2% - 146. 2% , while the contents of other heavy metals did not change much; the content of Cd, Pb, Cr, Ni and Cu in roots of the plant increased by 187. 8% , 197. 7% , 305. 7% , 228. 1% and 58. 2% , respectively, but that of Zn was not significantly affected. In the culture solution with salt ion concentration being more than 1 312. 4 mg ? L ' , the contents of the six heavy metals in the roots and shoots did not vary much between treatments different in salt concentrations, separately. Salt treatment apparently reduced the translocation coefficients of Pb, Cr, Ni and Cu in amaranth from the roots to the shoots, but it did not affect much that of Cd and Zn.%模拟不同淋洗脱盐阶段滩涂土壤孔隙水中盐分和重金属含量,通过苋菜水培试验,研究多种盐分离子(SO42-、Cl-、NO3-、CO32-、Na+、Ca2、K+和Mg2等)的共同作用下,苋菜对Zn、Cu、Ni、Cr、Pb和Cd 6种重金属的吸收、累积和转运的变化.结果表明,与对照相比,在不同盐分离子浓度影响下,苋菜茎叶中Cd的累积增幅为69.2% ~ 146.2%,而茎叶中其他重金属的含量无显著变化,苋菜根系中Cd、Pb、Cr、Ni和Cu含量的最大增幅分别为187.8%、197.7%、305.7%、228.1%和58.2%,但根系中Zn含量未受到显著影响.在相对较高的盐分离子浓度( >1 312.4 mg·L-1)范围内,不同盐分离子

  1. Comparative effect of salinity on ion accumulation, grain yield and stability salt tolerance degree of barley (Hordeum vulgare L. in different growth stage

    Directory of Open Access Journals (Sweden)

    Abdennaceur Ben Khaled

    2016-12-01

    Full Text Available In arid and semi-arid regions of the world, excess salts in agricultural land can limit crop production. Barley (Hordeum vulgare L. is one of the most salt tolerant crop species. This study was conducted to determine the effects of salinity on seed germination, mineral content and yield production of 14 barley accessions from two regions in the Southern Tunisia. First experiment was conducted in laboratory to test the effect of nine levels of NaCl concentrations in different germination parameter. Second experiments were conducted in a greenhouse. The accessions were grown in soil and exposed to three salinity levels. Salinity decreased significantly the germination rate and the germination rate index for all accessions. Na+ content, total dry matter and grain yield vary significantly with increasing salinity levels. The degree of tolerance varies between accessions in the different growth stage. A significant correlation were observed between ranking using grain yield and multivariate parameter. The tolerance degree based in germination rate and Na+ content don’t present significant correlation with yield ranking. Therefore, ranking using multivariate parameter can be the appropriate method to analysis the tolerance degree of barley under saline conditions. The differences response between accessions of local population of barley “Ardhaoui” reflected an important internal genetic variability against the salinity. This variability could be more explored and used for the barley breeding program. The accessions Ettalah, Chneni Tatouine and Elhezma showed more salt tolerance at 13 dS/m as indicated by the multivariate ranking using germination rate, Na+ content and grain yield.

  2. Rapid ion-exchange matrix removal for a decrease of detection limits in the analysis of salt-rich reservoir waters for fluorobenzoic acids by liquid chromatography coupled with tandem mass spectrometry.

    Science.gov (United States)

    Kubica, Paweł; Vacchina, Véronique; Wasilewski, Tomasz; Reynaud, Stéphanie; Szpunar, Joanna; Lobinski, Ryszard

    2017-02-01

    A matrix removal procedure with ion-exchange resin prior to analysis for 18 fluorinated benzoic acids (FBAs) tracers in saline (>25% salt) reservoir water was optimized. The elimination of >98% of salt and the simultaneous matrix sample cleanup allowed the direct analysis using the supernatant by liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS). This resulted in a gain in detection limits for most of the tracers in comparison with the reference method (direct analysis after minimum required dilution). The limits of detection (LODs) were in the range of 0.01-0.15 ng/ml and compared to other studies the developed method provided comparable limits of detection and advantage of simplified and shorter sample preparation. The presented method offers a considerable gain in simplicity and analysis time. Recoveries for all the tracers reached 80-100%, except for 2-FBA and 2,6-dFBA for which they were ca. 60%. The low recoveries were corrected by the use of five isotopically labeled internal standards. The method was validated by the analysis of spiked samples and by an independent comparison of the results with those obtained by solid-phase extraction LC-MS/MS method.

  3. Electrostatic interactions of asymmetrically charged membranes

    Science.gov (United States)

    Ben-Yaakov, Dan; Burak, Yoram; Andelman, David; Safran, S. A.

    2007-08-01

    We predict the nature (attractive or repulsive) and range (exponentially screened or long-range power law) of the electrostatic interactions of oppositely charged, planar plates as a function of the salt concentration and surface charge densities (whose absolute magnitudes are not necessarily equal). An analytical expression for the crossover between attractive and repulsive pressure is obtained as a function of the salt concentration. This condition reduces to the high-salt limit of Parsegian and Gingell where the interaction is exponentially screened and to the zero salt limit of Lau and Pincus in which the important length scales are the inter-plate separation and the Gouy-Chapman length. In the regime of low salt and high surface charges we predict —for any ratio of the charges on the surfaces— that the attractive pressure is long-ranged as a function of the spacing. The attractive pressure is related to the decrease in counter-ion concentration as the inter-plate distance is decreased. Our theory predicts several scaling regimes with different scaling expressions for the pressure as a function of salinity and surface charge densities. The pressure predictions can be related to surface force experiments of oppositely charged surfaces that are prepared by coating one of the mica surfaces with an oppositely charged polyelectrolyte.

  4. 不同盐度胁迫对芦荟生长和离子吸收分配的影响%Effects of Salt Concentration on Growth, Ion Absorption and Distribution of Aloe vera L.

    Institute of Scientific and Technical Information of China (English)

    马艳萍

    2012-01-01

    为探索芦荟对微咸水灌溉栽培的适应性,研究不同盐浓度对其生长和离子吸收分配的影响.结果表明,长期(120天)以含盐溶液灌溉栽培,盐浓度达200 mmol/L NaCl显著抑制芦荟生长,100 mmol/LNaCl对芦荟生长的抑制作用显著减轻,50 mmol/L NaCl不抑制芦荟生长.同时,以50 mmol/L NaCl溶液灌溉对芦荟盐分离子吸收分配影响轻微,但盐浓度达100 mmol/LNaCl对芦荟影响显著:根、茎、叶中K+含量显著下降,Na+、Cl-含量显著增大,K+/Na+大幅减小.X-射线能谱分析结果进一步表明,叶片贮水组织是芦荟积累盐分离子的重要部位,但100 mmol/L NaCl胁迫下芦荟根尖和叶片细胞中的离子平衡受到显著干扰.结果说明,芦荟适于用微咸水灌溉栽培,叶片贮水组织在缓解其盐胁迫中可起重要作用.%To explore the adaptability of irrigating aloe with weakly brine water, the effects of different concentration salinity stresses on growth, ion absorption and distribution of aloe plants were investigated.Experimental results showed that irrigation with 200 mmol/L NaCl for 120 d significantly retarded aloe growth, but the negative effects of irrigating aloe with 100 mmol/L NaCl on aloe growth were significantly relieved, even irrigating with 50 mmol/L NaCl did not retard aloe growth.The effects of irrigating with 50 mmol/L NaCl on ion absorption, transportation and distribution of aloe plants were not significant, but irrigating with 100 mmol/L NaCl were significant: K + contents of root, stem and leaf significantly decreased, Na + and Cl- content significantly increased, K+Na+ ratio significantly decreased.X-ray microanalysis results further showed that leaf aqueous was a main part of accumulating salt ion but ion homeostasis in root and leaf cells of aloe plants were significantly interrupted under 100 mmol/L NaCl stress.The experiment results suggested that Aloe vera L.was suitable to be irrigated with weakly brine water, and leaf

  5. Novel FinFET Device Using Asymmetric Doping

    DEFF Research Database (Denmark)

    Moradi, Farshad

    2012-01-01

    In this paper, a new technique is proposed to improve the device characteristics by introducing asymmetric doping at the source and the drain of the conventional FinFET. Specifically, the proposed device exhibits 9X increase of the Ion/Ioff ratio and 3X improved DIBL compared to conventional...

  6. RHIC operation with asymmetric collisions in 2015

    Energy Technology Data Exchange (ETDEWEB)

    Liu, C. [Brookhaven National Lab. (BNL), Upton, NY (United States); Aschenauer, C. [Brookhaven National Lab. (BNL), Upton, NY (United States); Atoian, G. [Brookhaven National Lab. (BNL), Upton, NY (United States); Blaskiewicz, M. [Brookhaven National Lab. (BNL), Upton, NY (United States); Brown, K. A. [Brookhaven National Lab. (BNL), Upton, NY (United States); Bruno, D. [Brookhaven National Lab. (BNL), Upton, NY (United States); Connolly, R. [Brookhaven National Lab. (BNL), Upton, NY (United States); Ottavio, T. D. [Brookhaven National Lab. (BNL), Upton, NY (United States); Drees, K. A. [Brookhaven National Lab. (BNL), Upton, NY (United States); Fischer, W. [Brookhaven National Lab. (BNL), Upton, NY (United States); Gardner, C. J. [Brookhaven National Lab. (BNL), Upton, NY (United States); Gu, X. [Brookhaven National Lab. (BNL), Upton, NY (United States); Hayes, T. [Brookhaven National Lab. (BNL), Upton, NY (United States); Huang, H. [Brookhaven National Lab. (BNL), Upton, NY (United States); Laster, J. S. [Brookhaven National Lab. (BNL), Upton, NY (United States); Luo, Y. [Brookhaven National Lab. (BNL), Upton, NY (United States); Makdisi, Y. [Brookhaven National Lab. (BNL), Upton, NY (United States); Marr, G. [Brookhaven National Lab. (BNL), Upton, NY (United States); Marusic, A. [Brookhaven National Lab. (BNL), Upton, NY (United States); Meot, F. [Brookhaven National Lab. (BNL), Upton, NY (United States); Mernick, K. [Brookhaven National Lab. (BNL), Upton, NY (United States); Michnoff, R. [Brookhaven National Lab. (BNL), Upton, NY (United States); Minty, M. [Brookhaven National Lab. (BNL), Upton, NY (United States); Montag, C. [Brookhaven National Lab. (BNL), Upton, NY (United States); Morris, J. [Brookhaven National Lab. (BNL), Upton, NY (United States); Narayan, G. [Brookhaven National Lab. (BNL), Upton, NY (United States); Nayak, S. [Brookhaven National Lab. (BNL), Upton, NY (United States); Nemesure, S. [Brookhaven National Lab. (BNL), Upton, NY (United States); Pile, P. [Brookhaven National Lab. (BNL), Upton, NY (United States); Poblaguev, A. [Brookhaven National Lab. (BNL), Upton, NY (United States); Ranjbar, V. [Brookhaven National Lab. (BNL), Upton, NY (United States); Robert-Demolaize, G. [Brookhaven National Lab. (BNL), Upton, NY (United States); Roser, T. [Brookhaven National Lab. (BNL), Upton, NY (United States); Schmidke, B. [Brookhaven National Lab. (BNL), Upton, NY (United States); Schoefer, V. [Brookhaven National Lab. (BNL), Upton, NY (United States); Severino, F. [Brookhaven National Lab. (BNL), Upton, NY (United States); Shrey, T. [Brookhaven National Lab. (BNL), Upton, NY (United States); Smith, K. [Brookhaven National Lab. (BNL), Upton, NY (United States); Steski, D. [Brookhaven National Lab. (BNL), Upton, NY (United States); Tepikian, S. [Brookhaven National Lab. (BNL), Upton, NY (United States); Trbojevic, D. [Brookhaven National Lab. (BNL), Upton, NY (United States); Tsoupas, N. [Brookhaven National Lab. (BNL), Upton, NY (United States); Wang, G. [Brookhaven National Lab. (BNL), Upton, NY (United States); White, S. [Brookhaven National Lab. (BNL), Upton, NY (United States); Yip, K. [Brookhaven National Lab. (BNL), Upton, NY (United States); Zaltsman, A. [Brookhaven National Lab. (BNL), Upton, NY (United States); Zeno, K. [Brookhaven National Lab. (BNL), Upton, NY (United States); Zhang, S. Y. [Brookhaven National Lab. (BNL), Upton, NY (United States)

    2015-08-07

    To study low-x shadowing/saturation physics as well as other nuclear effects [1], [2], proton-gold (p-Au, for 5 weeks) and proton-Aluminum (p-Al, for 2 weeks) collisions were provided for experiments in 2015 at the Relativistic Heavy Ion Collider (RHIC), with polarized proton beam in the Blue ring and Au/Al beam in the Yellow ring. The special features of the asymmetric run in 2015 will be introduced. The operation experience will be reviewed as well in the report.

  7. Effects of salt stress on ion distribution in different Echinops gmelini organs%盐胁迫对砂蓝刺头不同器官中离子分布的影响

    Institute of Scientific and Technical Information of China (English)

    杨小菊; 赵昕; 石勇; 李新荣

    2013-01-01

    砂蓝刺头为广泛分布于北方沙漠的一年生草本植物.本研究以砂蓝刺头幼苗为试材,采用营养液培养法研究了不同浓度NaCl胁迫下(盐浓度分别为0,100,200,300,400 mmol/L)砂蓝刺头幼苗胁迫6d后植株含水量变化,测定不同器官中Na+、Cl-、Si4+、K+、Ca2+的含量,并分析了K+/Na+、Ca2+/Na+、Si4+/Na+值的变化.研究结果表明,盐胁迫下,砂蓝刺头幼苗含水量在盐处理浓度为100,200,300,400 mmol/L时分别比对照升高了9.86%,1.41%,4.23%,8.45%,说明盐胁迫下植株提高了组织含水量,这将在一定程度上稀释了体内盐离子,减弱盐胁迫造成的生理干旱.盐胁迫下砂蓝刺头根部的Na+和Cl-含量高于叶片,这有利于渗透调节,同时减弱了盐胁迫对地上部的毒害;根系Si4+”、K+、Ca2+的含量及K+/Na+、Ca2+/Na+、Si4+/Na+值比对照显著性下降,叶部Si4+、K+的含量和K+/Na+,Ca2+/Na+,Si4+/Na+值比对照有所增加或差异不显著,这有利于维持地上部分离子稳定.分析离子选择性吸收的SNa+,K+数据发现,盐胁迫下砂蓝刺头根部拦截了部分Na+减缓了对地上部分的伤害,叶片对K+吸收具有很好的选择性,对于维持地上部分离子平衡和正常的光合作用具有重要意义.%Echinops gmelini is an annual wild plant distributed in arid desert areas of North China.The changes of water content,Na+,Cl-,Si4+,K+,Ca2+ contents and the K+/Na+,Ca2+/Na+,Si4+/Na+ ratios were measured in E.gmelini seedlings in a water control and under different concentrations (100,200,300,400 mmol/L) of NaCl stress:the water contents were found to increase by 9.86%,1.41%,4.23%,and 8.45%,respectively.Therefore the ability to absorb water was enhanced under salt stress,resulting in dilution of the cell's salt ion concentration to reduce physiological drought caused by salt ions.Na+ and Cl-contents of roots were higher than those of leaves under salt stress,so the salt ion damage on the leaves was

  8. Asymmetric synthesis v.4

    CERN Document Server

    Morrison, James

    1984-01-01

    Asymmetric Synthesis, Volume 4: The Chiral Carbon Pool and Chiral Sulfur, Nitrogen, Phosphorus, and Silicon Centers describes the practical methods of obtaining chiral fragments. Divided into five chapters, this book specifically examines initial chiral transmission and extension. The opening chapter describes the so-called chiral carbon pool, the readily available chiral carbon fragments used as building blocks in synthesis. This chapter also provides a list of 375 chiral building blocks, along with their commercial sources, approximate prices, and methods of synthesis. Schemes involving

  9. Asymmetric flow networks

    OpenAIRE

    Olaizola Ortega, María Norma; Valenciano Llovera, Federico

    2012-01-01

    This paper provides a new model of network formation that bridges the gap between the two benchmark models by Bala and Goyal, the one-way flow model, and the two-way flow model, and includes both as particular extreme cases. As in both benchmark models, in what we call an "asymmetric flow" network a link can be initiated unilaterally by any player with any other, and the flow through a link towards the player who supports it is perfect. Unlike those models, in the opposite direction there is ...

  10. Additional considerations about the role of ion size in charge reversal

    Energy Technology Data Exchange (ETDEWEB)

    Martin-Molina, A; Hidalgo-Alvarez, R [Grupo de Fisica de Fluidos y Biocoloides, Departamento de Fisica Aplicada, Facultad de Ciencias, Universidad de Granada, Granada 18071 (Spain); Quesada-Perez, M, E-mail: almartin@ugr.e [Departamento de Fisica, Universidad de Jaen, Escuela Politecnica Superior de Linares, 23700 Linares, Jaen (Spain)

    2009-10-21

    The effect of the ion size on the charge reversal process is studied via canonical Monte Carlo simulation. To this end, a primitive model of electrolyte is used to analyze the electric double layer formed by an asymmetric electrolyte in the presence of a charged planar wall. Different values of ion diameters and surface charge densities are used so as to determine the conditions at which the charge reversal first occurs. For each case, the apparent surface charge density is calculated as a function of the distance from the charged wall for the different electrolyte concentrations in order to establish the minimal salt concentration required for the charge reversal. We will refer to this electrolyte concentration as the reversal concentration and will show how it depends on the surface charge density and on the ion size. From the apparent surface charge density profiles, the distance from the wall at which the charge reversal arises as well as its intensity can be also inferred.

  11. A multinuclear solid-state NMR study of alkali metal ions in tetraphenylborate salts, M[BPh4] (M = Na, K, Rb and Cs): what is the NMR signature of cation-pi interactions?

    Science.gov (United States)

    Wu, Gang; Terskikh, Victor

    2008-10-16

    We report a multinuclear solid-state ( (23)Na, (39)K, (87)Rb, (133)Cs) NMR study of tetraphenylborate salts, M[BPh 4] (M = Na, K, Rb, Cs). These compounds are isostructural in the solid state with the alkali metal ion surrounded by four phenyl groups resulting in strong cation-pi interactions. From analyses of solid-state NMR spectra obtained under stationary and magic-angle spinning (MAS) conditions at 11.75 and 21.15 T, we have obtained the quadrupole coupling constants, C Q, and the chemical shift tensor parameters for the alkali metal ions in these compounds. We found that the observed quadrupole coupling constant for M (+) in M[BPh 4] is determined by a combination of nuclear quadrupole moment, Sternheimer antishielding factor, and unit cell dimensions. On the basis of a comparison between computed paramagnetic and diamagnetic contributions to the total chemical shielding values for commonly found cation-ligand interactions, we conclude that cation-pi interactions give rise to significantly lower paramagnetic shielding contributions than other cation-ligand interactions. As a result, highly negative chemical shifts are expected to be the NMR signature for cations interacting exclusively with pi systems.

  12. Hydrogen bonding in the crystal structure of the molecular salt of pyrazole-pyrazolium picrate.

    Science.gov (United States)

    Su, Ping; Song, Xue-Gang; Sun, Ren-Qiang; Xu, Xing-Man

    2016-06-01

    The asymmetric unit of the title organic salt [systematic name: 1H-pyrazol-2-ium 2,4,6-tri-nitro-phenolate-1H-pyrazole (1/1)], H(C3H4N2)2 (+)·C6H2N3O7 (-), consists of one picrate anion and one hydrogen-bonded dimer of a pyrazolium monocation. The H atom involved in the dimer N-H⋯N hydrogen bond is disordered over both symmetry-unique pyrazole mol-ecules with occupancies of 0.52 (5) and 0.48 (5). In the crystal, the component ions are linked into chains along [100] by two different bifurcated N-H⋯(O,O) hydrogen bonds. In addition, weak C-H⋯O hydrogen bonds link inversion-related chains, forming columns along [100].

  13. Excluded volume and ion-ion correlation effects on the ionic atmosphere around B-DNA: Theory, simulations, and experiments

    Energy Technology Data Exchange (ETDEWEB)

    Ovanesyan, Zaven; Marucho, Marcelo, E-mail: marcelo.marucho@utsa.edu [Department of Physics and Astronomy, The University of Texas at San Antonio, San Antonio, Texas 78249-5003 (United States); Medasani, Bharat [Department of Physics and Astronomy, The University of Texas at San Antonio, San Antonio, Texas 78249-5003 (United States); Computational Research Division, Lawrence Berkeley National Lab, Berkeley, California 94700 (United States); Fenley, Marcia O. [Institute of Molecular Biophysics, Florida State University, Tallahassee, Florida 32306 (United States); Guerrero-García, Guillermo Iván [Instituto de Física, Universidad Autónoma de San Luis Potosí, Álvaro Obregón 64, 78000 San Luis Potosí, San Luis Potosí (Mexico); Department of Chemistry and Department of Materials Science and Engineering, Northwestern University, Evanston, Illinois 60208 (United States); Olvera de la Cruz, Mónica [Department of Chemistry and Department of Materials Science and Engineering, Northwestern University, Evanston, Illinois 60208 (United States)

    2014-12-14

    The ionic atmosphere around a nucleic acid regulates its stability in aqueous salt solutions. One major source of complexity in biological activities involving nucleic acids arises from the strong influence of the surrounding ions and water molecules on their structural and thermodynamic properties. Here, we implement a classical density functional theory for cylindrical polyelectrolytes embedded in aqueous electrolytes containing explicit (neutral hard sphere) water molecules at experimental solvent concentrations. Our approach allows us to include ion correlations as well as solvent and ion excluded volume effects for studying the structural and thermodynamic properties of highly charged cylindrical polyelectrolytes. Several models of size and charge asymmetric mixtures of aqueous electrolytes at physiological concentrations are studied. Our results are in good agreement with Monte Carlo simulations. Our numerical calculations display significant differences in the ion density profiles for the different aqueous electrolyte models studied. However, similar results regarding the excess number of ions adsorbed to the B-DNA molecule are predicted by our theoretical approach for different aqueous electrolyte models. These findings suggest that ion counting experimental data should not be used alone to validate the performance of aqueous DNA-electrolyte models.

  14. Asymmetric photoredox transition-metal catalysis activated by visible light

    Science.gov (United States)

    Huo, Haohua; Shen, Xiaodong; Wang, Chuanyong; Zhang, Lilu; Röse, Philipp; Chen, Liang-An; Harms, Klaus; Marsch, Michael; Hilt, Gerhard; Meggers, Eric

    2014-11-01

    Asymmetric catalysis is seen as one of the most economical strategies to satisfy the growing demand for enantiomerically pure small molecules in the fine chemical and pharmaceutical industries. And visible light has been recognized as an environmentally friendly and sustainable form of energy for triggering chemical transformations and catalytic chemical processes. For these reasons, visible-light-driven catalytic asymmetric chemistry is a subject of enormous current interest. Photoredox catalysis provides the opportunity to generate highly reactive radical ion intermediates with often unusual or unconventional reactivities under surprisingly mild reaction conditions. In such systems, photoactivated sensitizers initiate a single electron transfer from (or to) a closed-shell organic molecule to produce radical cations or radical anions whose reactivities are then exploited for interesting or unusual chemical transformations. However, the high reactivity of photoexcited substrates, intermediate radical ions or radicals, and the low activation barriers for follow-up reactions provide significant hurdles for the development of efficient catalytic photochemical processes that work under stereochemical control and provide chiral molecules in an asymmetric fashion. Here we report a highly efficient asymmetric catalyst that uses visible light for the necessary molecular activation, thereby combining asymmetric catalysis and photocatalysis. We show that a chiral iridium complex can serve as a sensitizer for photoredox catalysis and at the same time provide very effective asymmetric induction for the enantioselective alkylation of 2-acyl imidazoles. This new asymmetric photoredox catalyst, in which the metal centre simultaneously serves as the exclusive source of chirality, the catalytically active Lewis acid centre, and the photoredox centre, offers new opportunities for the `green' synthesis of non-racemic chiral molecules.

  15. Additive Effects on Asymmetric Catalysis.

    Science.gov (United States)

    Hong, Liang; Sun, Wangsheng; Yang, Dongxu; Li, Guofeng; Wang, Rui

    2016-03-23

    This review highlights a number of additives that can be used to make asymmetric reactions perfect. Without changing other reaction conditions, simply adding additives can lead to improved asymmetric catalysis, such as reduced reaction time, improved yield, or/and increased selectivity.

  16. The asymmetric sandwich theorem

    CERN Document Server

    Simons, Stephen

    2011-01-01

    We discuss the asymmetric sandwich theorem, a generalization of the Hahn-Banach theorem. As applications, we derive various results on the existence of linear functionals that include bivariate, trivariate and quadrivariate generalizations of the Fenchel duality theorem. Most of the results are about affine functions defined on convex subsets of vector spaces, rather than linear functions defined on vector spaces. We consider both results that use a simple boundedness hypothesis (as in Rockafellar's version of the Fenchel duality theorem) and also results that use Baire's theorem (as in the Robinson-Attouch-Brezis version of the Fenchel duality theorem). This paper also contains some new results about metrizable topological vector spaces that are not necessarily locally convex.

  17. Asymmetric black dyonic holes

    Directory of Open Access Journals (Sweden)

    I. Cabrera-Munguia

    2015-04-01

    Full Text Available A 6-parametric asymptotically flat exact solution, describing a two-body system of asymmetric black dyons, is studied. The system consists of two unequal counterrotating Kerr–Newman black holes, endowed with electric and magnetic charges which are equal but opposite in sign, separated by a massless strut. The Smarr formula is generalized in order to take into account their contribution to the mass. The expressions for the horizon half-length parameters σ1 and σ2, as functions of the Komar parameters and of the coordinate distance, are displayed, and the thermodynamic properties of the two-body system are studied. Furthermore, the seven physical parameters satisfy a simple algebraic relation which can be understood as a dynamical scenario, in which the physical properties of one body are affected by the ones of the other body.

  18. Effect of ion interactions on the IR spectrum of benzenesulfonate ion. Restoration of sulfonate ion symmetry in sodium benzenesulfonate dimer

    Science.gov (United States)

    Shishlov, N. M.; Khursan, S. L.

    2016-11-01

    Literature data concerning the assignment of IR spectra of benzenesulfonate salts that serve as model compounds for aromatic sulfonate-containing ionomers and polyelectrolytes have been analyzed. The structures and IR spectra of free benzenesulfonate ion and its potassium and sodium salts have been calculated in B3LYP/6-311G(d,p) approximation. The bidentate coordination of counter-ions is energetically favorable for isolated ion pairs. In this coordination, the symmetry of sulfonate ion changes noticeably, which manifests itself as strong splitting of calculated vibrational modes of asymmetric stretching vibrations of Ssbnd O bonds, Δνas(SO3) = 154 cm-1 (K) and 180 cm-1 (Na). For sodium benzenesulfonate it is thermodynamically favorable to form a dimer (ΔG° = -37.6 kcal/mol) in which the joint effects of monodentate and bidentate coordinated Na cations result in equalization of Ssbnd O bond lengths and thus a considerable restoration of C3V symmetry of the sulfonate ion. The IR spectrum of the dimer in which Δνas(SO3) splitting is considerably smaller much better matches the experimental spectrum than the spectrum of an isolated ion pair. The major absorption bands in the IR spectrum of sodium benzenesulfonate have been assigned to theoretical vibrational modes of the dimer and, based on visualization of modes, to vibrations of certain bonds in the anion. In particular, the bands at 1200 and 1186 cm-1 have been assigned to νas(SO3), that at 1049 cm-1 to νs(SO3), and those at 628 and 572 cm-1 to δ(oop)s(SO3), and δ(ip)as(SO3), respectively. The strong effect of sulfonate ion environment on the positions of the absorption bands of stretching vibrations of Ssbnd O bonds makes it necessary to obtain data on exact structures of ion clusters for reliable assignment of absorption bands in experimental IR spectra of real sulfonate-containing systems.

  19. Novel synthetic approach for 1, 4-dihydroxyanthraquinone and the development of its Lithiated salts as anode material for aqueous rechargeable Lithium-ion batteries

    KAUST Repository

    Gurukar, Suresh Shivappa

    2015-08-17

    The influence of organic electrode materials in the field of lithium ion battery is becoming a keen interest for the present generation scientists. Here we are reporting a novel method of synthesis of electrode material by the combination of sono-chemical and thermal methods. The advantages of organic active material towards lithium ion battery are of core interest of this study. The structural confirmations are by FT-IR, 1H NMR, MALDI-TOF Mass Spectroscopy and powder XRD data. The electrochemical properties of Lithiated-1,4-dihydroxyanthraquinone were studied using electrochemical-techniques such as Cyclic Voltammetry, Galvanostatic Cyclic Potential Limitation and Potentiostatic Electrochemical Impedance Spectroscopy. The satisfactory results towards stability of active species in the aqueous media, reasonable discharge capacity with 0.9 V average voltages and agreeable cycling performance during charge-discharge process with reproducibility are achieved. For the construction of the full cell, the anode material was coupled with the LiNi1/3Co1/3Mn1/3O2 as a cathode material.

  20. 盐胁迫对油葵幼苗生长及离子吸收、分布的影响%Impact of Salt Stress on Growth and Ion Uptake of Different Parts of Oil Sunflower Seedlings

    Institute of Scientific and Technical Information of China (English)

    杨晓翠; 李文建; 曲颖; 张天虎

    2011-01-01

    [目的]研究不同NaCl浓度对油葵幼苗干、鲜重变化及离子吸收和分布的影响.[方法]不同浓度NaCl溶液模拟盐胁迫环境,测定油葵幼苗干、鲜重及离子含量.[结果]NaCl胁迫抑制油葵幼苗生长,降低了幼苗干、鲜重.叶片鲜重下降最明显,200mmol/L NaCl时下降约60%;子叶鲜重下降最少,200mmol/L NaCl时下降约13%.干重的下降程度同鲜重相似,200 mmol/L NaCl时根、茎、叶、子叶的干重与对照组相比分别下降约35%、39%、55%和8%.NaCl胁迫下,油葵幼苗根和茎中Na+含量上升,K+含量下降;Na+主要集中在根和茎中,叶片中较少;根中K+含量下降最明显,叶片中K+含量相对较高.根和茎中Ca2+、Mg2+含量下降,叶片和子叶中Ca2+含量相对稳定,子叶中Mg2+含量略上升.[结论]葵幼苗在NaCl胁迫下保持较高的矿物质元素吸收和运输以及相对稳定的离子平衡,这可能是油葵具有较高耐盐性的部分原因.%[Objective]The purpose was to discuss the effects of different NaCl concentrations on fresh weight and dry weight, ion absorption and distribution in oil sunflower seedlings.[Method]Under the simulated salt environment by using NaCl solutions at different concentrations,the dry weight, fresh weight and ion content of oil sunflower seedlings were determined.[Result]With the increase of NaCl concentration, the growth rate of oil sunflower seedling was inhibited.In addition, its fresh weight and dry weight also decreased; the fresh weight of leaf decreased most significantly by 60%, and that of cotyledon decreased most slightly by 13% at 200 mmol/L NaCl concentration.The dry weight of root,stem, leaf and cotyledon decreased by 35%, 39%, 55% and 8% respectively, showing a similar decreasing trend with fresh weight.Under NaCl stress, Na+ content in root and stem of oil sunflower seedling increased white K+ decreased.Na+ content was mainly concentrated in roots and stems much more than in leaves; K+ content

  1. 盐胁迫对油葵幼苗生长及离子吸收·分布的影响%Impact of Salt Stress on Growth and Ion Uptake of Different Parts of Oil Sunflower Seedlings

    Institute of Scientific and Technical Information of China (English)

    杨晓翠; 李文建; 曲颖; 张天虎

    2011-01-01

    [ Objective ] The purpose was to discuss the effects of different NaCl concentrations on fresh weight and dry weight,ion absorption and distribution in oil sunflower seedlings. [ Method ] Under the simulated salt environment by using NaCl solutions at different concentrations,the dry weight ,fresh weight and ion content of oil sunflower seedlings were determined. [ Result ] With the increase of NaCl concentration, the growth rate of oil sunflower seedling was inhibited. In addition ,its fresh weight and dry weight also decreased; the fresh weight of leaf decreased most significantly by 60% ,and that of cotyledon decreased most slightly by 13% at 200 mmol/L NaCl concentration. The dry weight of root,stem,leaf and cotyledon decreased by 35% ,39% ,55% and 8% respectively,showing a similar decreasing trend with fresh weight. Under NaCl stress,Na+ content in root and stem of oil sunflower seedling increased while K + decreased. Na+ content was mainly concentrated in roots and stems much more than in leaves; K + content in roots decreased most significantly by 21% compared with control ,and it was relatively high in leaf. Ca2+ and Mg2+ content was decreased slightly in roots and stems;Ca2+ content in leaves and cotyledons was stable;Mg2+ content was slightly increased. [ Conclusion ] Oil sunflower maintained high mineral ion absorption under salt stress, that maybe the part reason for high salt tolerance of oil sunflower seedlings.%[目的]研究不同浓度NaCl对油葵幼苗干、鲜重及离子吸收和分布的影响.[方法]采用不同浓度NaCl溶液模拟盐胁迫环境,测定油葵幼苗干、鲜重及离子含量.[结果]NaCl胁迫抑制油葵幼苗生长,降低了幼苗干、鲜重.叶片鲜重下降最明显,200mmol/L NaCl胁迫时下降约60%;子叶鲜重下降最少,200mmol/L NaCl时下降约13%.干重的下降程度同鲜重相似1200mmol/L NaCl胁迫时,根、茎、叶、子叶的干重与对照组相比分别下降约35%,39%,55%和8%.NaCl

  2. Salt Effect on Osmotic Pressure of Polyelectrolyte Solutions: Simulation Study

    Directory of Open Access Journals (Sweden)

    Jan-Michael Y. Carrillo

    2014-07-01

    Full Text Available Abstract: We present results of the hybrid Monte Carlo/molecular dynamics simulations of the osmotic pressure of salt solutions of polyelectrolytes. In our simulations, we used a coarse-grained representation of polyelectrolyte chains, counterions and salt ions. During simulation runs, we alternate Monte Carlo and molecular dynamics simulation steps. Monte Carlo steps were used to perform small ion exchange between simulation box containing salt ions (salt reservoir and simulation box with polyelectrolyte chains, counterions and salt ions (polyelectrolyte solution. This allowed us to model Donnan equilibrium and partitioning of salt and counterions across membrane impermeable to polyelectrolyte chains. Our simulations have shown that the main contribution to the system osmotic pressure is due to salt ions and osmotically active counterions. The fraction of the condensed (osmotically inactive counterions first increases with decreases in the solution ionic strength then it saturates. The reduced value of the system osmotic coefficient is a universal function of the ratio of the concentration of osmotically active counterions and salt concentration in salt reservoir. Simulation results are in a very good agreement with osmotic pressure measurements in sodium polystyrene sulfonate, DNA, polyacrylic acid, sodium polyanetholesulfonic acid, polyvinylbenzoic acid, and polydiallyldimethylammonium chloride solutions.

  3. Determination of iodine in table salt by iodide ion selective electrode%碘离子选择电极快速测定食盐中碘的含量

    Institute of Scientific and Technical Information of China (English)

    李玉成; 姚静

    2011-01-01

    This paper describes a rapid iodine content measure method by using the iodide ion selective electrode under a reducing buffer environment. With Na2SO3 as reducing agent and the buffer solution of 0.1 mol/L KNO^(3-)0.01moL/L tartaric acid, IO^(3-)is reduced to I^-. The iodide ion could be detected by the selective electrode with potentiometry. Then the detection result is compared with standard curved to determine the salt iodine content. The linear measurement interval is 10^(-1)~ 10^(-7) mol/L with the minimum detects concentration of 4.6 × 10^(-8)mol/L. The recovery coefficient is 98.2% - 100.7%.%利用碘离子选择电极,以0.1mol/LKNO(3^-)0.01mol/L酒石酸为总离子强度调节荆、Na2SO3为还原保护剂,将加碘食盐中的10(3^-)还原为I^-,在双液接饱和甘汞电极为参比电极的条件下,采用直接电位法和标准曲线法直接测定了溶液中的碘含量,实验结果表明,本方法线性范围10^(-1)~10^(-7)mol/L,检测下限4.6×10^(-8)mol/L,样品具有较好的回收率(98.2%-100.7%),可以用此方法测定食盐中I^-的含量。

  4. Asymmetric Gepner Models (Revisited)

    CERN Document Server

    Gato-Rivera, B

    2010-01-01

    We reconsider a class of heterotic string theories studied in 1989, based on tensor products of N=2 minimal models with asymmetric simple current invariants. We extend this analysis from (2,2) and (1,2) spectra to (0,2) spectra with SO(10) broken to the Standard Model. In the latter case the spectrum must contain fractionally charged particles. We find that in nearly all cases at least some of them are massless. However, we identify a large subclass where the fractional charges are at worst half-integer, and often vector-like. The number of families is very often reduced in comparison to the 1989 results, but there are no new tensor combinations yielding three families. All tensor combinations turn out to fall into two classes: those where the number of families is always divisible by three, and those where it is never divisible by three. We find an empirical rule to determine the class, which appears to extend beyond minimal N=2 tensor products. We observe that distributions of physical quantities such as th...

  5. Salt resistant crop plants

    KAUST Repository

    Roy, Stuart J.

    2014-04-01

    Soil salinity is a major constraint to agriculture. To improve salinity tolerance of crops, various traits can be incorporated, including ion exclusion, osmotic tolerance and tissue tolerance. We review the roles of a range of genes involved in salt tolerance traits. Different tissues and cells are adapted for specific and often diverse function, so it is important to express the genes in specific cell-types and to pyramid a range of traits. Modern biotechnology (marker- assisted selection or genetic engineering) needs to be increasingly used to introduce the correct combination of genes into elite crop cultivars. Importantly, the effects of introduced genes need to be evaluated in the field to determine their effect on salinity tolerance and yield improvement.

  6. {sup 7}Li NMR spectroscopy and ion conduction mechanism of composite gel polymer electrolyte: A comparative study with variation of salt and plasticizer with filler

    Energy Technology Data Exchange (ETDEWEB)

    Saikia, D. [Department of Chemistry, Center for Nanotechnology and R and D Center for Membrane Technology, Chung Yuan Christian University, Chung Li 32023, Taiwan (China); Chen-Yang, Y.W. [Department of Chemistry, Center for Nanotechnology and R and D Center for Membrane Technology, Chung Yuan Christian University, Chung Li 32023, Taiwan (China)], E-mail: yuiwhei@cycu.edu.tw; Chen, Y.T.; Li, Y.K.; Lin, S.I. [Department of Chemistry, Center for Nanotechnology and R and D Center for Membrane Technology, Chung Yuan Christian University, Chung Li 32023, Taiwan (China)

    2009-01-30

    Microporous composite gel polymer electrolyte (CGPE) has been prepared by incorporating the home-made silica aerogel (SAG) particles into the poly(vinylidene fluoride-co-hexafluoropropylene) (PVdF-HFP) copolymer/LiClO{sub 4} matrix. The ionic transport behavior of the electrolyte is studied with various experimental techniques such as AC impedance, X-ray diffraction (XRD), infrared (IR) spectra, nuclear magnetic resonance (NMR), scanning electron microscopy (SEM), differential scanning calorimetry (DSC) and thermogravimetric analyzer (TGA), etc. The results reveal that the SAG particles are well dispersed in the electrolytes and incorporate with the other components of the CGPEs. The solid-state {sup 7}Li NMR study has confirmed the interactions of lithium ion with SAG, polymer and plasticizers, causing to form the microporous structure and reduce the glass transition temperature and crystallinity, resulting in an increase in ionic conductivity of the CGPE. The best ionic conductivity (1.04 x 10{sup -2} S/cm at room temperature) is obtained from the composite polymer electrolyte containing 4 wt% of SAG, which is approximately four times higher than the ionic conductivity of the electrolyte without the filler.

  7. Magnetically Modified Asymmetric Supercapacitors Project

    Data.gov (United States)

    National Aeronautics and Space Administration — This Small Business Innovation Research Phase I project is for the development of an asymmetric supercapacitor that will have improved energy density and cycle life....

  8. Multicatalyst system in asymmetric catalysis

    CERN Document Server

    Zhou, Jian

    2014-01-01

    This book introduces multi-catalyst systems by describing their mechanism and advantages in asymmetric catalysis.  Helps organic chemists perform more efficient catalysis with step-by-step methods  Overviews new concepts and progress for greener and economic catalytic reactions  Covers topics of interest in asymmetric catalysis including bifunctional catalysis, cooperative catalysis, multimetallic catalysis, and novel tandem reactions   Has applications for pharmaceuticals, agrochemicals, materials, and flavour and fragrance

  9. On Asymmetric Quantum MDS Codes

    CERN Document Server

    Ezerman, Martianus Frederic; Ling, San

    2010-01-01

    Assuming the validity of the MDS Conjecture, the weight distribution of all MDS codes is known. Using a recently-established characterization of asymmetric quantum error-correcting codes, linear MDS codes can be used to construct asymmetric quantum MDS codes with $d_{z} \\geq d_{x}\\geq 2$ for all possible values of length $n$ for which linear MDS codes over $\\F_{q}$ are known to exist.

  10. Evaluation of capacity ion exchange of MMT-Na{sup +w}ith rare earth salts for use in polymeric nano composites; Avaliacao da capacidade de troca ionica da MMT-Na{sup +c}om sais de terras raras para aplicacao em nanocompositos polimericos

    Energy Technology Data Exchange (ETDEWEB)

    Maino, Isabel B.; Scienza, Lisete C. [Universidade de Caxias do Sul (UCS). CCET. Laboratorio de Protecao Superficial e Corrosao, Caxias do Sul, RS (Brazil); Piazza, Diego; Zattera, Ademir J. [Universidade de Caxias do Sul (UCS). CCET. Laboratorio de Polimeros (Brazil); Ferreira, Carlos A., E-mail: dpiazza1@ucs.br [Universidade Federal do Rio Grande do Sul (UFRGS). Laboratorio de Polimeros (Brazil)

    2011-07-01

    The modification of the montmorillonite clay is associated with materials science, arousing interest in science and technology provide significant improvements when incorporated into polymeric materials neat and conventional composites. The process of modification of clays occurs mainly through the ion exchange of exchangeable cations in its crystal structure. In this study, we performed ion exchange of sodium montmorillonite with rare earth salts (cerium) through two routes: centrifugation and filtration. The samples were characterized by X-ray diffraction (XRD) and energy dispersive analysis by X-ray (EDS). The sample obtained by the filtration route showed an increase of basal clay by XRD, indicating the presence of salts of cerium on the structure, and corroborated by EDS analysis. (author)

  11. Salt Tolerance of Desorption Electrospray Ionization (DESI)

    Energy Technology Data Exchange (ETDEWEB)

    Jackson, Ayanna U. [Purdue University; Talaty, Nari [Purdue University; Cooks, R G [Purdue University; Van Berkel, Gary J [ORNL

    2007-01-01

    Suppression of ion intensity in the presence of high salt matrices is common in most mass spectrometry ionization techniques. Desorption electrospray ionization (DESI) is an ionization method that exhibits salt tolerance, and this is investigated. DESI analysis was performed on three different drug mixtures in the presence of 0, 0.2, 2, 5, 10, and 20% NaCl:KCl weight by volume from seven different surfaces. At physiological concentrations individual drugs in each mixture were observed with each surface. Collision-induced dissociation (CID) was used to provide additional confirmation for select compounds. Multiple stage experiments, to MS5, were performed for select compounds. Even in the absence of added salt, the benzodiazepine containing mixture yielded sodium and potassium adducts of carbamazepine which masked the ions of interest. These adducts were eliminated by adding 0.1% 7M ammonium acetate to the standard methanol:water (1:1) spray solvent. Comparison of the salt tolerance of DESI with that of electrospray ionization (ESI) demonstrated much better signal/noise characteristics for DESI in this study. The salt tolerance of DESI was also studied by performing limit of detection and dynamic range experiments. Even at a salt concentration significantly above physiological concentrations, select surfaces were effective in providing spectra that allowed the ready identification of the compounds of interest. The already high salt tolerance of DESI can be optimized further by appropriate choices of surface and spray solution.

  12. Salt Acclimation of Cyanobacteria and Their Application in Biotechnology

    Directory of Open Access Journals (Sweden)

    Nadin Pade

    2014-12-01

    Full Text Available The long evolutionary history and photo-autotrophic lifestyle of cyanobacteria has allowed them to colonize almost all photic habitats on Earth, including environments with high or fluctuating salinity. Their basal salt acclimation strategy includes two principal reactions, the active export of ions and the accumulation of compatible solutes. Cyanobacterial salt acclimation has been characterized in much detail using selected model cyanobacteria, but their salt sensing and regulatory mechanisms are less well understood. Here, we briefly review recent advances in the identification of salt acclimation processes and the essential genes/proteins involved in acclimation to high salt. This knowledge is of increasing importance because the necessary mass cultivation of cyanobacteria for future use in biotechnology will be performed in sea water. In addition, cyanobacterial salt resistance genes also can be applied to improve the salt tolerance of salt sensitive organisms, such as crop plants.

  13. Salt acclimation of cyanobacteria and their application in biotechnology.

    Science.gov (United States)

    Pade, Nadin; Hagemann, Martin

    2014-12-29

    The long evolutionary history and photo-autotrophic lifestyle of cyanobacteria has allowed them to colonize almost all photic habitats on Earth, including environments with high or fluctuating salinity. Their basal salt acclimation strategy includes two principal reactions, the active export of ions and the accumulation of compatible solutes. Cyanobacterial salt acclimation has been characterized in much detail using selected model cyanobacteria, but their salt sensing and regulatory mechanisms are less well understood. Here, we briefly review recent advances in the identification of salt acclimation processes and the essential genes/proteins involved in acclimation to high salt. This knowledge is of increasing importance because the necessary mass cultivation of cyanobacteria for future use in biotechnology will be performed in sea water. In addition, cyanobacterial salt resistance genes also can be applied to improve the salt tolerance of salt sensitive organisms, such as crop plants.

  14. Detection, identification, and occurrence of thiotetronic acids in drinking water from underground sources by electrospray ionization-high field asymmetric waveform ion mobility spectrometry-quadrupole time-of-flight-mass spectrometry.

    Science.gov (United States)

    Lyczko, Jadwiga; Beach, Daniel; Gabryelski, Wojciech

    2015-10-01

    This paper demonstrates that electrospray ionization (ESI) with differential ion mobility spectroscopy (FAIMS) and "soft" mass spectrometry (MS) provide unique analytical capabilities that led to the discovery of sulfur-containing polar congeners of thiotetronic acid (TA) in drinking water from underground sources in Canada and the United States. Polar TAs accumulate in underground aquifers and appear to be the most abundant class of organic compounds in bottled water but cannot be detected by conventional mass spectrometry methods. We show that normally stable TAs are converted into very reactive ions in ESI which have to be analyzed using special conditions in ESI-FAIMS-MS to avoid extensive dissociation and ion/molecule reactions. De novo identification of 10 TAs was accomplished by the comparative tandem mass spectrometry analysis of authentic TA derivatives from groundwater samples and synthetic TA analogues prepared for this study. We present highlights of gas phase ion chemistry of polar TAs to explain their unique properties and reactivity. TA derivatives were originally isolated from soil bacteria and are of interest in the pharmaceutical industry due to their potent activity against a broad spectrum of pathogenic bacteria and negligible toxicity to mammals. We suspect that TAs are natural disinfection agents protecting groundwater from bacterial contamination, but these compound undergo modifications or decompose during an ozonation water treatment.

  15. SINGLE IONIC CONDUCTION OF POLYSILOXANE CONTAINING PROPYLENE CARBONATE GROUP AND LITHIUM POLYMERIC SALTS

    Institute of Scientific and Technical Information of China (English)

    CHEN Xiwen; FANG Shibi; HAO Ning; JIANG Yingyan

    1996-01-01

    The polysiloxane containing propylene carbonate side group and several lithium polymeric salts were synthesized. The structure were confirmed by IR, NMR and XPS. The blending systems of polysiloxane containing propylene carbonate group with different lithium polymeric salts were studied by ion conductivity, XPS and DSC. Different lithium polymeric salts in the blending system lead to conductivity arranged in the following sequence:poly(lithium ethylenebenzene sulfonate methylsiloxane) > poly(lithium propionate methylsiloxane) > poly(lithium propylsulfonate methylsiloxane) > poly(lithium styrenesulfonate).In the blending system the best single ion conductivity was close to 10-5 Scm-1 at room temperature. XPS showed that at low lithium salt concentration the conductivity increased with the increasing content of lithium salt, in consequence of the increase of free ion and solvent separated ion pair. At high lithium salt concentration the free ion was absent and the solvent-separated ion pair functioned as carrier.

  16. Synthesis, structure, and properties of azatriangulenium salts

    DEFF Research Database (Denmark)

    Laursen, B.W.; Krebs, Frederik C

    2001-01-01

    amines and, by virtue of its stepwise and irreversible nature, provides a powerful tool for the preparation of a wide variety of new heterocyclic carbenium salts. Several derivatives of the three new oxygen- and/or nitrogen-bridged triangulenium salts, azadioxa- (6), diazaoxa- (7......A general synthetic route to novel nitrogen-bridged heterocyclic carbenium ions of the acridinium and triangulenium type has been developed and investigated. The synthetic method is based on nucleophilic aromatic substitution (SNAr) on the tris(2,6-dimethoxyphenyl)carbenium ion (1) with primary...

  17. Physical chemistry and evolution of salt tolerance in halobacteria

    Science.gov (United States)

    Lanyi, J. K.

    1980-01-01

    The cellular constituents of extremely halophilic bacteria not only tolerate high salt concentration, but in many cases require it for optical functioning. The characteristics affected by salt include enzyme activity, stability, allosteric regulation, conformation and subunit association. The salt effects are of two major kinds: electrostatic shielding of negative charges by cations at low salt concentration, and hydrophobic stabilization by salting-out type salts at high salt concentration. The composition of halobacterial proteins shows an excess of acidic amino acids and a deficiency of nonpolar amino acids, which accounts for these effects. Since the cohesive forces are weaker and the repulsing forces are stronger in these proteins, preventing aggregation in salt, these structures are no longer suited for functioning in the absence of high salt concentrations. Unlike these nonspecific effects, ribosomes in halobacteria show marked preference for potassium over sodium ions. To ensure the proper intracellular ionic composition, powerful ion transport systems have evolved in the halobacteria, resulting in the extrusion of sodium ions and their replacement by potassium. It is likely that such membrane transport system for ionic movements is a necessary requisite for salt tolerance.

  18. The Design of Reactions, Catalysts and Materials with Aromatic Ions

    Science.gov (United States)

    Bandar, Jeffrey Scott

    (dialkylamino)cyclopropenimine catalyst to promote asymmetric Mannich reactions of glycinate imines and N -Boc-aldimines is described in Chapter 4. The products of this transformation are optically enriched diamino acid derivatives, an important motif widely utilized in medicinal and synthetic chemistry. Importantly, unlike existing methods, our technology promotes reactions between tert-butyl glycinate and aliphatic N-Boc-aldimine substrates. A preparative-scale reaction is demonstrated and derivatization of its product to several valuable chiral compounds is shown. Chapter 5 describes the use of tris(dialkylamino)cyclopropenium (TDAC) ions as a new class of onium-like catalyst. A simple TDAC chloride salt is prepared on a 75-gram scale and its use as a phase transfer catalyst for a variety of reactions is demonstrated. This same salt is also utilized as an epoxide opening catalyst for a variety of transformations, including the fixation of carbon dioxide. Chapter 6 briefly highlights several continued applications of the chemistry advanced throughout this thesis. First, the work of other members of the Lambert Group toward the continued development of cyclopropenimine chemistry is described. Second, a broad initiative between the Lambert and Campos Groups at Columbia University focused on the synthesis and application of TDAC-based polymers is introduced. Lastly, the identification of a previously unknown equilibrium between fulvenes and imines/aldehydes in the context of a new mode of catalysis is presented.

  19. Asymmetric synthesis of (-)-adaline.

    Science.gov (United States)

    Itoh, Toshimasa; Yamazaki, Naoki; Kibayashi, Chihiro

    2002-07-25

    [reaction: see text] An enantioselective total synthesis of (-)-adaline has been achieved starting from a chiral 6,6-disubstituted piperidone derivative previously prepared by diastereoselective allylation of a chiral tricyclic N-acyl-N,O-acetal. The key steps include lithium ion-activated SN2-type alkynylation of the tricyclic N,O-acetal leading to exclusive formation of the (6S)-ethynylpiperidine and ring-closing olefin metathesis of the (2R,6S)-cis-2,6-dialkenylpiperidine for constructing the bridged azabicyclononane.

  20. Effect of the difference in ion mobilities on traveling-wave electro-osmosis

    CERN Document Server

    Gonzalez, Antonio; Garcia-Sanchez, Pablo; Castellanos, Antonio

    2008-01-01

    We analyze the AC electro-osmotic motion of a 1:1 aqueous solution, taking into account the difference in mobilities and diffusion coefficients between positive and negative ions. This model serves to understand the behavior of common systems as a solution of NaCl in water. We pay special attention to two cases. First, the case of slightly different mobilities, that can model a KCl solution. Second, the case of a strongly asymmetric solution, with an almost vanishing mobility, applicable to the case of a salt where the negative ion is much more massive than the positive one. For all the cases, we perform the mathematical description and linear analysis of the problem, in order to establish the dependence of the induced velocity with the frequency, wavelength and amplitude of the applied voltage.

  1. Positron Acceleration in Electron-positron-ion Plasma Wakefield Regime Driven by an Ultraintense Laser with Asymmetric Pulse%电子、正电子、离子等离子体尾场中被加速正电子的研究

    Institute of Scientific and Technical Information of China (English)

    艾孜买提·外力; 沙依甫加马力·达吾来提; 买买提艾力·巴克; 桑海波; 谢柏松

    2014-01-01

    为了研究在激光驱动的等离子体尾场中被加速正电子的动力学,使用了由电子、正电子、离子组成的等离子体,通过采用数值模拟方法得到了非对称脉冲驱动的尾波场中被加速的正电子的运动相图、动能变化,势能。数据结果表明:非对称激光脉冲驱动尾场中正电子得到很高的能量。提高等离子体中的正电子比例会使电子和正电子的加速效果减弱。在非对称激光脉冲驱动的激光尾场中,为了有效地加速正电子,要选择恰当的上升激光脉冲长度和下降激光脉冲长度。%Positron acceleration in the plasma wakefield driven by an ultraintense laser with asymmetric pulse are studied in frame of Hamiltonian formalism. The plasma is constituted by the electrons, positrons and ions. From numerical results it is found that the larger positron fraction results in the smaller momentum increase and the lower net energy gain. In other words, as the increase of the positron fraction the acceleration effciency for both of the electrons and positrons will be reduced. Moreover there exists an optimal pulse length asymmetric ratio for the highest positron net energy gain when positron fraction of plasma is given.

  2. Isospin dependent properties of asymmetric nuclear matter

    CERN Document Server

    Chowdhury, P Roy; Samanta, C

    2009-01-01

    The density dependence of nuclear symmetry energy is determined from a systematic study of the isospin dependent bulk properties of asymmetric nuclear matter using the isoscalar and the isovector components of density dependent M3Y interaction. The incompressibility $K_\\infty$ for the symmetric nuclear matter, the isospin dependent part $K_{asy}$ of the isobaric incompressibility and the slope $L$ are all in excellent agreement with the constraints recently extracted from measured isotopic dependence of the giant monopole resonances in even-A Sn isotopes, from the neutron skin thickness of nuclei and from analyses of experimental data on isospin diffusion and isotopic scaling in intermediate energy heavy-ion collisions. This work provides a fundamental basis for the understanding of nuclear matter under extreme conditions, and validates the important empirical constraints obtained from recent experimental data.

  3. The structure and IR signatures of the arginine-glutamate salt bridge. Insights from the classical MD simulations.

    Science.gov (United States)

    Vener, M V; Odinokov, A V; Wehmeyer, C; Sebastiani, D

    2015-06-01

    Salt bridges and ionic interactions play an important role in protein stability, protein-protein interactions, and protein folding. Here, we provide the classical MD simulations of the structure and IR signatures of the arginine (Arg)-glutamate (Glu) salt bridge. The Arg-Glu model is based on the infinite polyalanine antiparallel two-stranded β-sheet structure. The 1 μs NPT simulations show that it preferably exists as a salt bridge (a contact ion pair). Bidentate (the end-on and side-on structures) and monodentate (the backside structure) configurations are localized [Donald et al., Proteins 79, 898-915 (2011)]. These structures are stabilized by the short (+)N-H⋯O(-) bonds. Their relative stability depends on a force field used in the MD simulations. The side-on structure is the most stable in terms of the OPLS-AA force field. If AMBER ff99SB-ILDN is used, the backside structure is the most stable. Compared with experimental data, simulations using the OPLS all-atom (OPLS-AA) force field describe the stability of the salt bridge structures quite realistically. It decreases in the following order: side-on > end-on > backside. The most stable side-on structure lives several nanoseconds. The less stable backside structure exists a few tenth of a nanosecond. Several short-living species (solvent shared, completely separately solvated ionic groups ion pairs, etc.) are also localized. Their lifetime is a few tens of picoseconds or less. Conformational flexibility of amino acids forming the salt bridge is investigated. The spectral signature of the Arg-Glu salt bridge is the IR-intensive band around 2200 cm(-1). It is caused by the asymmetric stretching vibrations of the (+)N-H⋯O(-) fragment. Result of the present paper suggests that infrared spectroscopy in the 2000-2800 frequency region may be a rapid and quantitative method for the study of salt bridges in peptides and ionic interactions between proteins. This region is usually not considered in spectroscopic

  4. The structure and IR signatures of the arginine-glutamate salt bridge. Insights from the classical MD simulations

    Energy Technology Data Exchange (ETDEWEB)

    Vener, M. V., E-mail: mikhail.vener@gmail.com [Mendeleev University of Chemical Technology, Moscow (Russian Federation); Odinokov, A. V. [Photochemistry Center of the Russian Academy of Sciences, Moscow (Russian Federation); Wehmeyer, C. [Free University, Berlin (Germany); Sebastiani, D. [Martin-Luther-Universität Halle-Wittenberg, Halle (Germany)

    2015-06-07

    Salt bridges and ionic interactions play an important role in protein stability, protein-protein interactions, and protein folding. Here, we provide the classical MD simulations of the structure and IR signatures of the arginine (Arg)–glutamate (Glu) salt bridge. The Arg-Glu model is based on the infinite polyalanine antiparallel two-stranded β-sheet structure. The 1 μs NPT simulations show that it preferably exists as a salt bridge (a contact ion pair). Bidentate (the end-on and side-on structures) and monodentate (the backside structure) configurations are localized [Donald et al., Proteins 79, 898–915 (2011)]. These structures are stabilized by the short {sup +}N–H⋯O{sup −} bonds. Their relative stability depends on a force field used in the MD simulations. The side-on structure is the most stable in terms of the OPLS-AA force field. If AMBER ff99SB-ILDN is used, the backside structure is the most stable. Compared with experimental data, simulations using the OPLS all-atom (OPLS-AA) force field describe the stability of the salt bridge structures quite realistically. It decreases in the following order: side-on > end-on > backside. The most stable side-on structure lives several nanoseconds. The less stable backside structure exists a few tenth of a nanosecond. Several short-living species (solvent shared, completely separately solvated ionic groups ion pairs, etc.) are also localized. Their lifetime is a few tens of picoseconds or less. Conformational flexibility of amino acids forming the salt bridge is investigated. The spectral signature of the Arg-Glu salt bridge is the IR-intensive band around 2200 cm{sup −1}. It is caused by the asymmetric stretching vibrations of the {sup +}N–H⋯O{sup −} fragment. Result of the present paper suggests that infrared spectroscopy in the 2000–2800 frequency region may be a rapid and quantitative method for the study of salt bridges in peptides and ionic interactions between proteins. This region is

  5. The structure and IR signatures of the arginine-glutamate salt bridge. Insights from the classical MD simulations

    Science.gov (United States)

    Vener, M. V.; Odinokov, A. V.; Wehmeyer, C.; Sebastiani, D.

    2015-06-01

    Salt bridges and ionic interactions play an important role in protein stability, protein-protein interactions, and protein folding. Here, we provide the classical MD simulations of the structure and IR signatures of the arginine (Arg)-glutamate (Glu) salt bridge. The Arg-Glu model is based on the infinite polyalanine antiparallel two-stranded β-sheet structure. The 1 μs NPT simulations show that it preferably exists as a salt bridge (a contact ion pair). Bidentate (the end-on and side-on structures) and monodentate (the backside structure) configurations are localized [Donald et al., Proteins 79, 898-915 (2011)]. These structures are stabilized by the short +N-H⋯O- bonds. Their relative stability depends on a force field used in the MD simulations. The side-on structure is the most stable in terms of the OPLS-AA force field. If AMBER ff99SB-ILDN is used, the backside structure is the most stable. Compared with experimental data, simulations using the OPLS all-atom (OPLS-AA) force field describe the stability of the salt bridge structures quite realistically. It decreases in the following order: side-on > end-on > backside. The most stable side-on structure lives several nanoseconds. The less stable backside structure exists a few tenth of a nanosecond. Several short-living species (solvent shared, completely separately solvated ionic groups ion pairs, etc.) are also localized. Their lifetime is a few tens of picoseconds or less. Conformational flexibility of amino acids forming the salt bridge is investigated. The spectral signature of the Arg-Glu salt bridge is the IR-intensive band around 2200 cm-1. It is caused by the asymmetric stretching vibrations of the +N-H⋯O- fragment. Result of the present paper suggests that infrared spectroscopy in the 2000-2800 frequency region may be a rapid and quantitative method for the study of salt bridges in peptides and ionic interactions between proteins. This region is usually not considered in spectroscopic

  6. NA+/H+ ANTIPORT ACTIVITY IN TONOPLAST VESICLES FROM ROOTS OF THE SALT-TOLERANT PLANTAGO-MARITIMA AND THE SALT-SENSITIVE PLANTAGO-MEDIA

    NARCIS (Netherlands)

    STAAL, M; MAATHUIS, FJM; ELZENGA, JTM; OVERBEEK, JHM; PRINS, HBA

    1991-01-01

    Plantago species differ in their strategy towards salt stress, a major difference being the uptake and distribution of Na+ ions. A salt-sensitive (Plantago media L.) and a salt-tolerant (P. maritima L.) species were compared with respect to Na+/H+ antiport activities at the tonoplast. After exposure

  7. Insensitivity to Salt of Assembly of a Rigid Biopolymer Aggrecan

    Science.gov (United States)

    Horkay, Ferenc; Basser, Peter J.; Hecht, Anne-Marie; Geissler, Erik

    2008-08-01

    Many polyelectrolytes, ranging from sulfonated polystyrene to DNA, exhibit a strong sensitivity of their phase behavior to salt concentration, especially to higher valence salts, which often lead to phase separation. We show that the stiff polyelectrolyte aggrecan exhibits a qualitatively different behavior. Specifically, the scattering properties of aggrecan solutions are exceptionally insensitive to the addition of calcium salt, conferring on aggrecan the role of an ion reservoir mediating calcium metabolism in cartilage and bone, and also providing osmotic resilience to compressive load.

  8. Salt Acclimation of Cyanobacteria and Their Application in Biotechnology

    OpenAIRE

    Nadin Pade; Martin Hagemann

    2014-01-01

    The long evolutionary history and photo-autotrophic lifestyle of cyanobacteria has allowed them to colonize almost all photic habitats on Earth, including environments with high or fluctuating salinity. Their basal salt acclimation strategy includes two principal reactions, the active export of ions and the accumulation of compatible solutes. Cyanobacterial salt acclimation has been characterized in much detail using selected model cyanobacteria, but their salt sensing and regulatory mechanis...

  9. Nonlinear effects in asymmetric catalysis.

    Science.gov (United States)

    Satyanarayana, Tummanapalli; Abraham, Susan; Kagan, Henri B

    2009-01-01

    There is a need for the preparation of enantiomerically pure compounds for various applications. An efficient approach to achieve this goal is asymmetric catalysis. The chiral catalyst is usually prepared from a chiral auxiliary, which itself is derived from a natural product or by resolution of a racemic precursor. The use of non-enantiopure chiral auxiliaries in asymmetric catalysis seems unattractive to preparative chemists, since the anticipated enantiomeric excess (ee) of the reaction product should be proportional to the ee value of the chiral auxiliary (linearity). In fact, some deviation from linearity may arise. Such nonlinear effects can be rich in mechanistic information and can be synthetically useful (asymmetric amplification). This Review documents the advances made during the last decade in the use of nonlinear effects in the area of organometallic and organic catalysis.

  10. Asymmetric distances for binary embeddings.

    Science.gov (United States)

    Gordo, Albert; Perronnin, Florent; Gong, Yunchao; Lazebnik, Svetlana

    2014-01-01

    In large-scale query-by-example retrieval, embedding image signatures in a binary space offers two benefits: data compression and search efficiency. While most embedding algorithms binarize both query and database signatures, it has been noted that this is not strictly a requirement. Indeed, asymmetric schemes that binarize the database signatures but not the query still enjoy the same two benefits but may provide superior accuracy. In this work, we propose two general asymmetric distances that are applicable to a wide variety of embedding techniques including locality sensitive hashing (LSH), locality sensitive binary codes (LSBC), spectral hashing (SH), PCA embedding (PCAE), PCAE with random rotations (PCAE-RR), and PCAE with iterative quantization (PCAE-ITQ). We experiment on four public benchmarks containing up to 1M images and show that the proposed asymmetric distances consistently lead to large improvements over the symmetric Hamming distance for all binary embedding techniques.

  11. Asymmetric Synthesis via Chiral Aziridines

    DEFF Research Database (Denmark)

    Tanner, David Ackland; Harden, Adrian; Wyatt, Paul

    1996-01-01

    A series of chiral bis(aziridines) has been synthesised and evaluated as chelating ligands for a variety of asymmetric transformations mediated by metals [Os (dihydroxylation), Pd (allylic alkylation) Cu (cyclopropanation and aziridination, Li (1,2-addition of organolithiums to imines)]. In the b......A series of chiral bis(aziridines) has been synthesised and evaluated as chelating ligands for a variety of asymmetric transformations mediated by metals [Os (dihydroxylation), Pd (allylic alkylation) Cu (cyclopropanation and aziridination, Li (1,2-addition of organolithiums to imines...

  12. The solubility of toluene in aqueous salt solutions.

    Science.gov (United States)

    Poulson, S; Harrington, R; Drever, J

    1999-03-01

    The solubility of toluene has been measured in distilled water, and in various inorganic salt solutions. Values of the Setschenow constant, K(S), which quantify toluene solubility versus salt concentration, have been determined for each salt. Values of K(S) are compared to the activity of water for the salt solutions. Data from this study, consistent with earlier data, suggests that the effects of salts upon toluene solubility are non-additive. This contrasts the additive behavior of inorganic salts upon the solubility of nonpolar organic compounds, such as benzene and naphthalene, reported in the literature. Specific interaction between slightly polar toluene and ions in solution is suggested as a possible explanation for the non-additive effect of salts on the solubility of toluene.

  13. The behaviour of salt and salt caverns

    NARCIS (Netherlands)

    Fokker, P.A.

    1995-01-01

    Salts are mined for both storage and extraction purposes, either via dry or solution mining techniques. For operational, environmental and geological purposes, it is important to understand and predict the in situ behaviour of salt, in particular the creep and strength characteristics. A micro-mecha

  14. Cooking without salt

    Science.gov (United States)

    DASH diet; High blood pressure - DASH; Hypertension - DASH; Low-salt diet - DASH ... Explore cooking with salt substitutes. Add a splash of lemon and other citrus fruits, or wine, to soups and other dishes. Or use them ...

  15. Determination of the deliquesce point in double salts and in in-situ multicomponent salts with DVS equipment

    DEFF Research Database (Denmark)

    Rörig-Dalgaard, Inge

    2014-01-01

    Accelerated salt induced deterioration occurs by frequently changes across the deliquescence point. Therefore does the actual deliquescence point of the present salts have a major impact on preventive conservation being able to ensure a relative humidity not causing salt phase transition and to in......-situ desalination as dissolution of the salts is the essential criterion to enable transport of salt (ions) in the construction. In the present work deliquescence points were measured with dynamic vapor sorption (DVS) equipment in salt mixtures and the results are shown to be in agreement with values from...... the literature. Also in-situ-multi salt samples were measured including the difference between the second critical relative humidity and the efflorescence relative humidity being a measure for the critical supersaturation required for crystallization at the specific experimental conditions. The DVS equipment...

  16. Synthesis of Asymmetric Propanetriol Analogues

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    From natural tartaric acid, (R)-2-benzyloxy-3-(2-tetrahydropyranyloxy) propanol 3 was designed and synthesized, and (R)-2-benzyloxy-3-(4-methoxybenzyloxy) propanol 7 was prepared in a new method. They can be used as chiral synthons of lysophosphatidic acid and other compounds with asymmetric propanetriol backbone.

  17. Salt splitting using ceramic membranes

    Energy Technology Data Exchange (ETDEWEB)

    Kurath, D.E. [Pacific Northwest National Lab., Richland, WA (United States)

    1997-10-01

    Many radioactive aqueous wastes in the DOE complex have high concentrations of sodium that can negatively affect waste treatment and disposal operations. Sodium can decrease the durability of waste forms such as glass and is the primary contributor to large disposal volumes. Waste treatment processes such as cesium ion exchange, sludge washing, and calcination are made less efficient and more expensive because of the high sodium concentrations. Pacific Northwest National Laboratory (PNNL) and Ceramatec Inc. (Salt Lake City UT) are developing an electrochemical salt splitting process based on inorganic ceramic sodium (Na), super-ionic conductor (NaSICON) membranes that shows promise for mitigating the impact of sodium. In this process, the waste is added to the anode compartment, and an electrical potential is applied to the cell. This drives sodium ions through the membrane, but the membrane rejects most other cations (e.g., Sr{sup +2}, Cs{sup +}). The charge balance in the anode compartment is maintained by generating H{sup +} from the electrolysis of water. The charge balance in the cathode is maintained by generating OH{sup {minus}}, either from the electrolysis of water or from oxygen and water using an oxygen cathode. The normal gaseous products of the electrolysis of water are oxygen at the anode and hydrogen at the cathode. Potentially flammable gas mixtures can be prevented by providing adequate volumes of a sweep gas, using an alternative reductant or destruction of the hydrogen as it is generated. As H{sup +} is generated in the anode compartment, the pH drops. The process may be operated with either an alkaline (pH>12) or an acidic anolyte (pH <1). The benefits of salt splitting using ceramic membranes are (1) waste volume reduction and reduced chemical procurement costs by recycling of NaOH; and (2) direct reduction of sodium in process streams, which enhances subsequent operations such as cesium ion exchange, calcination, and vitrification.

  18. Ion-binding of glycine zwitterion with inorganic ions in biologically relevant aqueous electrolyte solutions.

    Science.gov (United States)

    Fedotova, Marina V; Kruchinin, Sergey E

    2014-06-01

    The ion-binding between inorganic ions and charged functional groups of glycine zwitter-ion in NaCl(aq), KCl(aq), MgCl2(aq), and CaCl2(aq) has been investigated over a wide salt concentration range by using integral equation theory in the 3D-RISM approach. These systems mimic biological systems where binding of ions to charged residues at protein surfaces is relevant. It has been found that the stability of ion pairs formed by the carboxylate group and added inorganic cations decreases in the sequence Mg(2+)>Ca(2+)>Na(+)>K(+). However, all formed ion pairs are weak and decrease in stability with increasing salt concentration. On the other hand, at a given salt concentration the stability of (-NH3(+):Cl(-))aq ion pairs is similar in all studied systems. The features of ion-binding and the salt concentration effect on this process are discussed.

  19. Salt preferences of honey bee water foragers.

    Science.gov (United States)

    Lau, Pierre W; Nieh, James C

    2016-03-01

    The importance of dietary salt may explain why bees are often observed collecting brackish water, a habit that may expose them to harmful xenobiotics. However, the individual salt preferences of water-collecting bees were not known. We measured the proboscis extension reflex (PER) response of Apis mellifera water foragers to 0-10% w/w solutions of Na, Mg and K, ions that provide essential nutrients. We also tested phosphate, which can deter foraging. Bees exhibited significant preferences, with the most PER responses for 1.5-3% Na and 1.5% Mg. However, K and phosphate were largely aversive and elicited PER responses only for the lowest concentrations, suggesting a way to deter bees from visiting contaminated water. We then analyzed the salt content of water sources that bees collected in urban and semi-urban environments. Bees collected water with a wide range of salt concentrations, but most collected water sources had relatively low salt concentrations, with the exception of seawater and swimming pools, which had >0.6% Na. The high levels of PER responsiveness elicited by 1.5-3% Na may explain why bees are willing to collect such salty water. Interestingly, bees exhibited high individual variation in salt preferences: individual identity accounted for 32% of variation in PER responses. Salt specialization may therefore occur in water foragers.

  20. Quantitative Analysis of Soil Salt and Its Main Ions Based on Visible/Near Infrared Spectroscopy in Estuary Area of Yellow River%基于可见/近红外光谱的黄河口区土壤盐分及其主要离子的定量分析

    Institute of Scientific and Technical Information of China (English)

    刘亚秋; 陈红艳; 王瑞燕; 常春艳; 陈哲

    2016-01-01

    Objective]It is crucial to quantitatively and accurately detect saline soil for the prevention of soil salinization and agricultural sustainable development. The objective of this study is to find the characteristic spectra of soil salt and its main ions, and build a quantitative analysis model of soil salinization which is suitable for the estuary area of Yellow River to improve the accuracy and stability of the quantitative analysis. [Method] Kenli County in Shandong Province was selected as the experimental area. Firstly, 96 representative soil samples were collected on October 5th-9th, 2014. After soil sample were dried, the contents of soil salt and ions were analyzed. Then the visible and near infrared reflectance hyperspectra of the soil samples were measured in the laboratory by ASD Fieldspec 3 spectrometer, smoothed and transformed to the first deviation. Secondly, the response spectra of salt and its main ions (Cl-, Na+, Ca2+)were analyzed, first soil salinity and main ions content and the first derivative spectra of reflectance by band correlation analysis, according to the principle of correlation coefficient and significant, their sensitive bands were selected as the characteristic bands, feature bands with maximum correlation coefficient were chosen as the significant feature bands. Then the characteristic spectra which can represent soil salt and main ions (Cl-, Na+, Ca2+) were analyzed synthetically using correlation analysis and identified. Finally, the methods of multiple linear regression (MLR), support vector machine (SVM) and random forest (RF) were used respectively to build quantitative analysis models of soil salinity and ions contents. [Result] The overall shape and trend of the spectra curves of soil salinity and major ions (Cl-, Na+, Ca2+) content in study area were very similar. Soil salinity and major ions (Cl-, Na+, Ca2+) spectra response regions were determined to be 1 320-1 495, 1 790-1 920, 2 120-2 290 nm. On account of the

  1. Genotypic Differences in Antioxidative Stress and Salt Tolerance of Three Poplars Under Salt Stress

    Institute of Scientific and Technical Information of China (English)

    Wang Ruigang; Chen Shaoliang; Ma Haiyuan; Liu Liyuan; Li He; Weng Haijiao; Hao Zhiyong; Yang Shuang

    2006-01-01

    To evaluate genotypic difference in antioxidative ability and salt tolerance in poplars,the authors investigated the effects of increasing content of soil NaC1 on salt concentration in leaves,superoxide dismutase (SOD) and peroxidase (POD) activities,malondialdehyde (MDA)content,and membrane permeability (MP) in Populus euphratica Oliv.,P.popularis"35-44,"and P.×euramericana cv.I-214 (hereafter abbreviated as P.cv.I-214).Na+and C1- concentrations in leaves of P.popularis increased markedly over the increase of the duration of exposure to salinity,and culminated after 28 days of salt stress.SOD and POD activities declined correspondingly,followed by significant increases of MDA and MP,and leaf injury was finally observed.Compared with P.popularis,leaf Na+and C1- in P.cv.I-214 exhibited a trend similar to P.popularis,but a lower salt-induced increase of MDA and permeability was observed and lighter leaf necrosis occurred.In contrast to P.popularis and P.cv.I-214,SOD and POD activities in P.euphratica leaves increased rapidiy at the beginning of salt stress with a light soil NaCl concentration of 58.5 mmol/L.Furthermore,salt ion concentration,MDAcontent,and MP in P.euphratica leaves did not increase significantly during 28 days of increasing salt stress.Therefore,the increase in MP in P.popularis and P.cv.I-214 had a close relationship with a salt buildup in leaves under increasing salt stress.Salt-induced declines of SOD and POD activities might accelerate lipid peroxide and consequently resulted in ion leakage.P.euphratica rapidly activated antioxidant enzymes after the onset of salt stress,which might reduce the accumulation of reactive oxygen species and the subsequent acceleration of lipid peroxide.P.euphratica leaves exhibited a higher capacity to exclude salt in a longer period of increasing salinity,thus limited salt-induced lipid peroxide and MP,which contributed to membrane integrity maintenance and salt tolerance of P.euphratica.

  2. The salts of Mars

    Science.gov (United States)

    Clark, B. C.; Van Hart, D. C.

    1981-01-01

    Salt compounds are apparently an important component of the fine-grained regolith on Mars. Salt enrichment may be explained either as a secondary concentration of chemical weathering products or as direct incorporation of planetary released volatiles. Geochemical measurements and chemical relationships constrain the salt species and resultant physicochemical consequences. A likely assemblage is dominated by (Mg,Na)SO4, NaCl, and (Mg,Ca)CO3. Formation of brine in equilibrium with such a salt mixture is unlikely under the temperature and water-vapor restrictions prevalent over most, if not all, of the Martian surface. Acidic conditions, accompanying salt formation, favor the preferential destruction of susceptible igneous minerals.

  3. Chiral recognition in salts of trans-1,2-diaminocyclohexane and optically active tartaric acids: crystal structure of 1:2 salt of ( S, S)-diaminocyclohexane with ( R, R)-tartaric acid

    Science.gov (United States)

    Rychlewska, Urszula

    1999-01-01

    X-ray results for the highly organised superstructure (space group P6 522) of the 1:2 salt of (1 S,2 S)-diaminocyclohexane with ( R, R)-tartaric acid ( 1) are compared with the previously reported [1] crystal structures of two diastereomeric 1:1 salts of ( R, R)-diaminocyclohexane with ( R, R)- and ( S, S)-tartaric acid. The asymmetric unit of the unit cell of 1 consists of one molecule of ( S, S)-diaminocyclohexane, one molecule of ( R, R)-hydrogentartrate, half a molecule of ( R, R)-tartaric acid, half of an ( R, R)-tartrate anion, and a water molecule. The presence of all three ionisation states of ( R, R)-tartrate in one crystal is most unusual, as is the anti conformation of the carboxyl group in ( R, R)-tartaric acid. Association of ( S, S)-diaminocyclohexane and ( R, R)-hydrogentartrate involves three-centre hydrogen bonds between ammonium groups as donors and α-hydroxycarboxylate and α-hydroxycarboxyl moieties as acceptors. The remaining hydrogen bonds stabilise this motif and expand it to three dimensions. The results provide some insights into the enantioselective association of trans-1,2-diaminocyclohexane with optically active tartaric acids, the main driving force being the hydrogen bonding. While in a homochiral 1:1 salt the two ions combine by a scissors-shaped hydrogen bonding motif formed by two ammonium functions as donors and vicinal hydroxyl groups as acceptors, in heterochiral salts the cation and anion species join together via three-centre hydrogen bonds between ammonium functions and planar or nearly planar α-hydroxycarboxylate moieties.

  4. Asymmetric Multilevel Diversity Coding and Asymmetric Gaussian Multiple Descriptions

    CERN Document Server

    Mohajer, Soheil; Diggavi, Suhas N

    2009-01-01

    We consider the asymmetric multilevel diversity (A-MLD) coding problem, where a set of $2^K-1$ information sources, ordered in a decreasing level of importance, is encoded into $K$ messages (or descriptions). There are $2^K-1$ decoders, each of which has access to a non-empty subset of the encoded messages. Each decoder is required to reproduce the information sources up to a certain importance level depending on the combination of descriptions available to it. We obtain a single letter characterization of the achievable rate region for the 3-description problem. In contrast to symmetric multilevel diversity coding, source-separation coding is not sufficient in the asymmetric case, and ideas akin to network coding need to be used strategically. Based on the intuitions gained in treating the A-MLD problem, we derive inner and outer bounds for the rate region of the asymmetric Gaussian multiple description (MD) problem with three descriptions. Both the inner and outer bounds have a similar geometric structure t...

  5. Modelling asymmetric growth in crowded plant communities

    DEFF Research Database (Denmark)

    Damgaard, Christian

    2010-01-01

    A class of models that may be used to quantify the effect of size-asymmetric competition in crowded plant communities by estimating a community specific degree of size-asymmetric growth for each species in the community is suggested. The model consists of two parts: an individual size-asymmetric ......A class of models that may be used to quantify the effect of size-asymmetric competition in crowded plant communities by estimating a community specific degree of size-asymmetric growth for each species in the community is suggested. The model consists of two parts: an individual size...

  6. Cyclodextrins in Asymmetric and Stereospecific Synthesis

    Directory of Open Access Journals (Sweden)

    Fliur Macaev

    2015-09-01

    Full Text Available Since their discovery, cyclodextrins have widely been used as green and easily available alternatives to promoters or catalysts of different chemical reactions in water. This review covers the research and application of cyclodextrins and their derivatives in asymmetric and stereospecific syntheses, with their division into three main groups: (1 cyclodextrins promoting asymmetric and stereospecific catalysis in water; (2 cyclodextrins’ complexes with transition metals as asymmetric and stereospecific catalysts; and (3 cyclodextrins’ non-metallic derivatives as asymmetric and stereospecific catalysts. The scope of this review is to systematize existing information on the contribution of cyclodextrins to asymmetric and stereospecific synthesis and, thus, to facilitate further development in this direction.

  7. Long-wavelength limit of the static structure factors for mixtures of two simple molten salts with a common ion and generalized Bhatia-Thornton formalism: Molecular dynamics study of molten mixture Ag(Br{sub 0.7}I{sub 0.3})

    Energy Technology Data Exchange (ETDEWEB)

    Bitrian, Vicente [Departament de Fisica i Enginyeria Nuclear, Universitat Politecnica de Catalunya, Campus Nord UPC, Edifici B4-B5, Despatx B4-204, Jordi Girona 1-3, 08034 Barcelona (Spain); Trullas, Joaquim [Departament de Fisica i Enginyeria Nuclear, Universitat Politecnica de Catalunya, Campus Nord UPC, Edifici B4-B5, Despatx B4-204, Jordi Girona 1-3, 08034 Barcelona (Spain)], E-mail: quim.trullas@upc.edu; Silbert, Moises [School of Mathematics, University of East Anglia, Norwich NR4 7QF (United Kingdom)

    2008-12-15

    The relation between thermodynamic properties and the long-wavelength limit of the structure factors for mixtures of two simple molten salts with a common ion is derived. While the long-wavelength limit of the partial structure factors for binary ionic systems is directly related to the isothermal compressibility, for ternary ionic systems it is shown that it is also related to the mean square thermal fluctuation in the relative concentration of the non-common ions. This result leads to a generalization of the Bhatia-Thornton formalism. From the local fluctuations in the total number-density, charge-density, and relative concentration, six static structure factors, and the corresponding spatial correlation functions, are defined. By introducing three complementary structure factors, it is possible to describe either these mixtures as a system of cations and anions irrespective of the species of the non-common ions, or solely the binary subsystem of the non-common ions. The generalized structure factors and their long-wavelength limits are illustrated by molecular dynamics simulation results of the molten mixture Ag(Br{sub 0.7}I{sub 0.3}). The mixture retains the charge order characteristic of pure molten monovalent salts and the topological order observed in monovalent ionic melts in which the cations are smaller than the anions, while the main trends of the anionic chemical order are those of simple binary alloys. The long-wavelength fluctuations in the local relative concentration are found to be very sensitive to the choice of the short-range interactions between the non-common ions.

  8. [Raman spectrometry of several saturated fatty acids and their salts].

    Science.gov (United States)

    Luo, Man; Guan, Ping; Liu, Wen-hui; Liu, Yan

    2006-11-01

    Saturated fatty acids and their salts widely exist in the nature, and they are well known as important chemical materials. Their infrared spectra have been studied in detail. Nevertheless, few works on the Raman spectra characteristics of saturated fatty acids and their salts have been published before. Man-made crystals of acetic acid, stearic acid, calcium acetate, magnesium acetate, calcium stearate and magnesium stearate were investigated by means of Fourier transform Raman spectrometry for purpose of realizing their Raman spectra. Positive ions can cause the distinctions between the spectra of saturated fatty acids and their salts. The differences in mass and configuration between Ca2+ and Mg2+ result in the Raman spectra's diversity between calcium and magnesium salts of saturated fatty acids. Meanwhile, it is considered that the long carbon chain weakened the influence of different positive ions on the salts of saturated fatty acids.

  9. Asymmetric trienamine catalysis: new opportunities in amine catalysis.

    Science.gov (United States)

    Kumar, Indresh; Ramaraju, Panduga; Mir, Nisar A

    2013-02-07

    Amine catalysis, through HOMO-activating enamine and LUMO-activating iminium-ion formation, is receiving increasing attention among other organocatalytic strategies, for the activation of unmodified carbonyl compounds. Particularly, the HOMO-raising activation concept has been applied to the greatest number of asymmetric transformations through enamine, dienamine, and SOMO-activation strategies. Recently, trienamine catalysis, an extension of amine catalysis, has emerged as a powerful tool for synthetic chemists with a novel activation strategy for polyenals/polyenones. In this review article, we discuss the initial developments of trienamine catalysis for highly asymmetric Diels-Alder reactions with different dienophiles and emerging opportunities for other types of cycloadditions and cascade reactions.

  10. Ion mobility sensor system

    Science.gov (United States)

    Xu, Jun; Watson, David B.; Whitten, William B.

    2013-01-22

    An ion mobility sensor system including an ion mobility spectrometer and a differential mobility spectrometer coupled to the ion mobility spectrometer. The ion mobility spectrometer has a first chamber having first end and a second end extending along a first direction, and a first electrode system that generates a constant electric field parallel to the first direction. The differential mobility spectrometer includes a second chamber having a third end and a fourth end configured such that a fluid may flow in a second direction from the third end to the fourth end, and a second electrode system that generates an asymmetric electric field within an interior of the second chamber. Additionally, the ion mobility spectrometer and the differential mobility spectrometer form an interface region. Also, the first end and the third end are positioned facing one another so that the constant electric field enters the third end and overlaps the fluid flowing in the second direction.

  11. Terahertz metamaterial with asymmetric transmission

    CERN Document Server

    Singh, R; Menzel, C; Rockstuhl, C; Azad, A K; Cheville, R A; Lederer, F; Zhang, W; Zheludev, N I

    2009-01-01

    We show for the first time that a planar metamaterial, an array of coupled metal split-ring resonators with a unit cell lacking mirror symmetry, exhibits asymmetric transmission of terahertz radiation propagating through it in opposite directions. This intriguing effect, that is compatible with Lorentz reciprocity and time-reversal, depends on a directional difference in conversion efficiency of the incident circularly polarized wave into one of opposite handedness, that is only possible in lossy low-symmetry planar chiral metamaterials. We show that asymmetric transmission is linked to excitation of enantiomerically sensitive plasmons, these are induced charge-field excitations that depend on the mutual handedness of incident wave and metamaterial pattern. Various bands of positive, negative and zero phase and group velocities have been identified indicating the opportunity to develop polarization sensitive negative index and slow light media based on such metamaterials.

  12. Asymmetric information and macroeconomic dynamics

    Science.gov (United States)

    Hawkins, Raymond J.; Aoki, Masanao; Roy Frieden, B.

    2010-09-01

    We show how macroeconomic dynamics can be derived from asymmetric information. As an illustration of the utility of this approach we derive the equilibrium density, non-equilibrium densities and the equation of motion for the response to a demand shock for productivity in a simple economy. Novel consequences of this approach include a natural incorporation of time dependence into macroeconomics and a common information-theoretic basis for economics and other fields seeking to link micro-dynamics and macro-observables.

  13. Asymmetrical Γ-Source Inverters

    DEFF Research Database (Denmark)

    Wei, Mo; Poh Chiang, Loh; Blaabjerg, Frede

    2014-01-01

    , inverters with coupled transformers have been introduced, but they usually lead to high turns ratio, and hence many winding turns, at high gain. An alternative would then be the asymmetrical Γ-source inverters proposed in this paper, whose gain is raised by lowering their turns ratio toward unity. The input...... current drawn by the proposed inverters is smoother and, hence, more adaptable by the source. Theories and experimental results have been presented in this paper for validating the concepts proposed....

  14. Up-down asymmetric tokamaks

    CERN Document Server

    Ball, Justin

    2016-01-01

    Bulk toroidal rotation has proven capable of stabilising both dangerous MHD modes and turbulence. In this thesis, we explore a method to drive rotation in large tokamaks: up-down asymmetry in the magnetic equilibrium. We seek to maximise this rotation by finding optimal up-down asymmetric flux surface shapes. First, we use the ideal MHD model to show that low order external shaping (e.g. elongation) is best for creating up-down asymmetric flux surfaces throughout the device. Then, we calculate realistic up-down asymmetric equilibria for input into nonlinear gyrokinetic turbulence analysis. Analytic gyrokinetics shows that, in the limit of fast shaping effects, a poloidal tilt of the flux surface shaping has little effect on turbulent transport. Since up-down symmetric surfaces do not transport momentum, this invariance to tilt implies that devices with mirror symmetry about any line in the poloidal plane will drive minimal rotation. Accordingly, further analytic investigation suggests that non-mirror symmetri...

  15. Superacid-Based Lithium Salts For Polymer Electrolytes

    Science.gov (United States)

    Nagasubramanian, Ganesan; Prakash, Surya; Shen, David H.; Surampudi, Subbarao; Olah, George

    1995-01-01

    Solid polymer electrolytes exhibiting high lithium-ion conductivities made by incorporating salts of superacids into thin films of polyethylene oxide (PEO). These and other solid-polymer electrolytes candidates for use in rechargeable lithium-based electrochemical cells. Increases in room-temperature lithium-ion conductivities of solid electrolytes desirable because they increase achievable power and energy densities.

  16. Leaf sodium accumulation facilitates salt stress adaptation and preserves photosystem functionality in salt stressed Ocimum basilicum

    NARCIS (Netherlands)

    Mancarella, S.; Orsini, F.; Oosten, van M.J.; Sanoubar, R.; Stanghellini, C.; Kondo, S.; Gianquinto, G.; Maggio, A.

    2016-01-01

    In this study, plant growth, water relations, ABA levels, ion accumulation patterns and chlorophyll fluorescence were functionally linked to salt stress tolerance of two basil cultivars (Napoletano and Genovese) with different stress sensitivity levels. Plants were treated with salty water at 0,

  17. Transport-limited water splitting at ion-selective interfaces during concentration polarization

    DEFF Research Database (Denmark)

    Nielsen, Christoffer Peder; Bruus, Henrik

    2014-01-01

    We present an analytical model of salt- and water-ion transport across an ion-selective interface based on an assumption of local equilibrium of the water-dissociation reaction. The model yields current-voltage characteristics and curves of water-ion current versus salt-ion current, which are in ...

  18. Asymmetric Schiff bases derived from diaminomaleonitrile and their metal complexes

    Science.gov (United States)

    Yang, Jianjie; Shi, Rufei; Zhou, Pei; Qiu, Qiming; Li, Hui

    2016-02-01

    Asymmetric Schiff bases, due to its asymmetric structure, can be used as asymmetric catalyst, antibacterial, and mimic molecules during simulate biological processes, etc. In recent years, research on synthesis and properties of asymmetric Schiff bases have become an increase interest of chemists. This review summarizes asymmetric Schiff bases derived from diaminomaleonitrile (DAMN) and DAMN-based asymmetric Schiff bases metal complexes. Applications of DAMN-based asymmetric Schiff bases are also discussed in this review.

  19. Spontaneous baryogenesis from asymmetric inflaton

    Energy Technology Data Exchange (ETDEWEB)

    Takahashi, Fuminobu [Tohoku Univ., Sendai (Japan). Dept. of Physics; Tokyo Univ., Chiba (Japan). Kavli IPMU (WPI), UTIAS; Yamada, Masaki [Tokyo Univ., Chiba (Japan). Kavli IPMU (WPI), UTIAS; Tokyo Univ., Chiba (Japan). Inst. for Cosmic Ray Research; DESY Hamburg (Germany)

    2015-10-15

    We propose a variant scenario of spontaneous baryogenesis from asymmetric inflaton based on current-current interactions between the inflaton and matter fields with a non-zero B-L charge. When the inflaton starts to oscillate around the minimum after inflation, it may lead to excitation of a CP-odd component, which induces an effective chemical potential for the B-L number through the current-current interactions. We study concrete inflation models and show that the spontaneous baryogenesis scenario can be naturally implemented in the chaotic inflation in supergravity.

  20. The asymmetric Goos-H\\"anchen effect

    OpenAIRE

    Araujo, Manoel P.; Carvalho, Silvânia A.; De Leo, Stefano

    2013-01-01

    We show in which conditions optical gaussian beams, propagating throughout an homogeneous dielectric right angle prism, present an asymmetric Goos-H\\"anchen (GH) effect. This asymmetric behavior is seen for incidence at critical angles and happens in the propagation direction of the outgoing beam. The asymmetric GH effect can be also seen as an amplification of the standard GH shift. Due to the fact that it only depends on the ratio between the wavelength and the minimal waist size of the inc...

  1. Review of Composite Asymmetric Spur Gear

    OpenAIRE

    Sandeep C. Dhaduti; Dr. S. G. Sarganachari

    2015-01-01

    Gears made from composite materials are widely used in many power and motion transmission applications. Due to lower weight to stiffness ratio, composite gears may be replaced by conventional material gears in power transmission systems. Design of gears with asymmetric teeth enables to increase load capacity, reduce weight, size and vibration level. This article includes a summary of asymmetric gear design parameters, new developments of asymmetric spur gear and their ...

  2. The asymmetric Goos-H\\"anchen effect

    CERN Document Server

    Araujo, Manoel P; De Leo, Stefano

    2014-01-01

    We show in which conditions optical gaussian beams, propagating throughout an homogeneous dielectric right angle prism, present an asymmetric Goos-H\\"anchen (GH) effect. This asymmetric behavior is seen for incidence at critical angles and happens in the propagation direction of the outgoing beam. The asymmetric GH effect can be also seen as an amplification of the standard GH shift. Due to the fact that it only depends on the ratio between the wavelength and the minimal waist size of the incoming gaussian beam, it can be also used to determine one of these parameters. Multiple peaks interference is an additional phenomenon seen in the presence of such asymmetric effects.

  3. SALT for Language Acquisition.

    Science.gov (United States)

    Bancroft, W. Jane

    1996-01-01

    Discusses Schuster's Suggestive-Accelerative Learning Techniques (SALT) Method, which combines Lozanov's Suggestopedia with such American methods as Asher's Total Physical Response and Galyean's Confluent Education. The article argues that students trained with the SALT Method have higher achievement scores and better attitudes than others. (14…

  4. Hydroxycarboxylic acids and salts

    Energy Technology Data Exchange (ETDEWEB)

    Kiely, Donald E; Hash, Kirk R; Kramer-Presta, Kylie; Smith, Tyler N

    2015-02-24

    Compositions which inhibit corrosion and alter the physical properties of concrete (admixtures) are prepared from salt mixtures of hydroxycarboxylic acids, carboxylic acids, and nitric acid. The salt mixtures are prepared by neutralizing acid product mixtures from the oxidation of polyols using nitric acid and oxygen as the oxidizing agents. Nitric acid is removed from the hydroxycarboxylic acids by evaporation and diffusion dialysis.

  5. Geomechanics of bedded salt

    Energy Technology Data Exchange (ETDEWEB)

    Serata, S.; Milnor, S.W.

    1979-06-08

    Creep data from the literature search is reinterpreted by SGI, resulting in a better understanding of the temperature and stress state dependence of the octahedral creep rate and the octahedral shear strength. The concept of a transition strength between the elastic and the plastic states is in agreement with the data. The elastic and rheological properties of salt are described, and a set of constitutive equations is presented. The dependence of material properties on parameters such as temperature is considered. Findings on the permeability of salt are summarized, and the in-situ behavior of openings in bedded salt is described based on extensive engineering experience. A stress measuring system utilizing a finite element computer code is discussed. Geological factors affecting the stability of salt openings are considered, and the Stress Control Technique for designing stable openings in bedded salt formations is explained.

  6. Salt and nephrolithiasis.

    Science.gov (United States)

    Ticinesi, Andrea; Nouvenne, Antonio; Maalouf, Naim M; Borghi, Loris; Meschi, Tiziana

    2016-01-01

    Dietary sodium chloride intake is nowadays globally known as one of the major threats for cardiovascular health. However, there is also important evidence that it may influence idiopathic calcium nephrolithiasis onset and recurrence. Higher salt intake has been associated with hypercalciuria and hypocitraturia, which are major risk factors for calcium stone formation. Dietary salt restriction can be an effective means for secondary prevention of nephrolithiasis as well. Thus in this paper, we review the complex relationship between salt and nephrolithiasis, pointing out the difference between dietary sodium and salt intake and the best methods to assess them, highlighting the main findings of epidemiologic, laboratory and intervention studies and focusing on open issues such as the role of dietary salt in secondary causes of nephrolithiasis.

  7. Effects of salts on the gelatinization and retrogradation properties of maize starch and waxy maize starch.

    Science.gov (United States)

    Wang, Wei; Zhou, Hongxian; Yang, Hong; Zhao, Siming; Liu, Youming; Liu, Ru

    2017-01-01

    The objective of this study was to evaluate the effects of salts on the gelatinization and retrogradation of maize and waxy maize starch. Experimental results showed that the salting-out or structure-making ions, such as F(-) and SO4(2-), decreased the swelling power, solubility and transparency of both starches, but increased the gelatinization temperature, enthalpy, and syneresis, due to the tendency of these ions to protect the hydrogen bond links among starch molecules. On the other hand, the salting-in or structure-breaking ions, such as I(-) and SCN(-), exhibited the opposite effects. Microscopic observations confirmed such effects of salts on both starches. Furthermore, the effects of salts were more significant on waxy maize and on normal maize starch. Generally, salts could significantly influence on the gelatinization and retrogradation of maize and waxy maize starch, following the order of the Hofmeister series.

  8. Thin lenses of asymmetric power

    Directory of Open Access Journals (Sweden)

    W. F. Harris

    2009-12-01

    Full Text Available It is generally supposed that thin systems, including refracting surfaces and thin lenses, have powers that are necessarily symmetric.  In other words they have powers which can be represented assymmetric dioptric power matrices and in the familar spherocylindrical form used in optometry and ophthalmology.  This paper shows that this is not correct and that it is indeed possible for a thin system to have a power that is not symmetric and which cannot be expressed in spherocylindrical form.  Thin systems of asymmetric power are illustratedby means of a thin lens that is modelled with small prisms and is chosen to have a dioptric power ma-trix that is antisymmetric.  Similar models can be devised for a thin system whose dioptric power matrix is any  2 2 ×  matrix.  Thus any power, symmetric, asymmetric or antisymmetric, is possible for a thin system.  In this sense our understanding of the power of thin systems is now complete.

  9. Excitons in asymmetric quantum wells

    Science.gov (United States)

    Grigoryev, P. S.; Kurdyubov, A. S.; Kuznetsova, M. S.; Ignatiev, I. V.; Efimov, Yu. P.; Eliseev, S. A.; Petrov, V. V.; Lovtcius, V. A.; Shapochkin, P. Yu.

    2016-09-01

    Resonance dielectric response of excitons is studied for the high-quality InGaAs/GaAs heterostructures with wide asymmetric quantum wells (QWs). To highlight effects of the QW asymmetry, we have grown and studied several heterostructures with nominally square QWs as well as with triangle-like QWs. Several quantum confined exciton states are experimentally observed as narrow exciton resonances. A standard approach for the phenomenological analysis of the profiles is generalized by introducing different phase shifts for the light waves reflected from the QWs at different exciton resonances. Good agreement of the phenomenological fit to the experimentally observed exciton spectra for high-quality structures allowed us to reliably obtain parameters of the exciton resonances: the exciton transition energies, the radiative broadenings, and the phase shifts. A direct numerical solution of the Schrödinger equation for the heavy-hole excitons in asymmetric QWs is used for microscopic modeling of the exciton resonances. Remarkable agreement with the experiment is achieved when the effect of indium segregation is taken into account. The segregation results in a modification of the potential profile, in particular, in an asymmetry of the nominally square QWs.

  10. Asymmetric Laguerre-Gaussian beams

    Science.gov (United States)

    Kovalev, A. A.; Kotlyar, V. V.; Porfirev, A. P.

    2016-06-01

    We introduce a family of asymmetric Laguerre-Gaussian (aLG) laser beams. The beams have been derived via a complex-valued shift of conventional LG beams in the Cartesian plane. While propagating in a uniform medium, the first bright ring of the aLG beam becomes less asymmetric and the energy is redistributed toward peripheral diffraction rings. The projection of the orbital angular momentum (OAM) onto the optical axis is calculated. The OAM is shown to grow quadratically with increasing asymmetry parameter of the aLG beam, which equals the ratio of the shift to the waist radius. Conditions for the OAM becoming equal to the topological charge have been derived. For aLG beams with zero radial index, we have deduced an expression to define the intensity maximum coordinates and shown the crescent-shaped intensity pattern to rotate during propagation. Results of the experimental generation and rotation of aLG beams agree well with theoretical predictions.

  11. Plant Responses to Salt Stress: Adaptive Mechanisms

    Directory of Open Access Journals (Sweden)

    Jose Ramón Acosta-Motos

    2017-02-01

    Full Text Available This review deals with the adaptive mechanisms that plants can implement to cope with the challenge of salt stress. Plants tolerant to NaCl implement a series of adaptations to acclimate to salinity, including morphological, physiological and biochemical changes. These changes include increases in the root/canopy ratio and in the chlorophyll content in addition to changes in the leaf anatomy that ultimately lead to preventing leaf ion toxicity, thus maintaining the water status in order to limit water loss and protect the photosynthesis process. Furthermore, we deal with the effect of salt stress on photosynthesis and chlorophyll fluorescence and some of the mechanisms thought to protect the photosynthetic machinery, including the xanthophyll cycle, photorespiration pathway, and water-water cycle. Finally, we also provide an updated discussion on salt-induced oxidative stress at the subcellular level and its effect on the antioxidant machinery in both salt-tolerant and salt-sensitive plants. The aim is to extend our understanding of how salinity may affect the physiological characteristics of plants.

  12. Salt tolerance evolves more frequently in C4 grass lineages.

    Science.gov (United States)

    Bromham, L; Bennett, T H

    2014-03-01

    Salt tolerance has evolved many times in the grass family, and yet few cereal crops are salt tolerant. Why has it been so difficult to develop crops tolerant of saline soils when salt tolerance has evolved so frequently in nature? One possible explanation is that some grass lineages have traits that predispose them to developing salt tolerance and that without these background traits, salt tolerance is harder to achieve. One candidate background trait is photosynthetic pathway, which has also been remarkably labile in grasses. At least 22 independent origins of the C4 photosynthetic pathway have been suggested to occur within the grass family. It is possible that the evolution of C4 photosynthesis aids exploitation of saline environments, because it reduces transpiration, increases water-use efficiency and limits the uptake of toxic ions. But the observed link between the evolution of C4 photosynthesis and salt tolerance could simply be due to biases in phylogenetic distribution of halophytes or C4 species. Here, we use a phylogenetic analysis to investigate the association between photosynthetic pathway and salt tolerance in the grass family Poaceae. We find that salt tolerance is significantly more likely to occur in lineages with C4 photosynthesis than in C3 lineages. We discuss the possible links between C4 photosynthesis and salt tolerance and consider the limitations of inferring the direction of causality of this relationship.

  13. Crushed Salt Constitutive Model

    Energy Technology Data Exchange (ETDEWEB)

    Callahan, G.D.

    1999-02-01

    The constitutive model used to describe the deformation of crushed salt is presented in this report. Two mechanisms -- dislocation creep and grain boundary diffusional pressure solution -- are combined to form the basis for the constitutive model governing the deformation of crushed salt. The constitutive model is generalized to represent three-dimensional states of stress. Upon complete consolidation, the crushed-salt model reproduces the Multimechanism Deformation (M-D) model typically used for the Waste Isolation Pilot Plant (WIPP) host geological formation salt. New shear consolidation tests are combined with an existing database that includes hydrostatic consolidation and shear consolidation tests conducted on WIPP and southeastern New Mexico salt. Nonlinear least-squares model fitting to the database produced two sets of material parameter values for the model -- one for the shear consolidation tests and one for a combination of the shear and hydrostatic consolidation tests. Using the parameter values determined from the fitted database, the constitutive model is validated against constant strain-rate tests. Shaft seal problems are analyzed to demonstrate model-predicted consolidation of the shaft seal crushed-salt component. Based on the fitting statistics, the ability of the model to predict the test data, and the ability of the model to predict load paths and test data outside of the fitted database, the model appears to capture the creep consolidation behavior of crushed salt reasonably well.

  14. Asymmetric catalysis : ligand design and microwave acceleration

    OpenAIRE

    Bremberg, Ulf

    2000-01-01

    This thesis deals partly with the design and synthesis ofligands for use in asymmetric catalysis, and partly with theapplication of microwave heating on metal-based asymmetriccatalytic reactions. Enantiomerically pure pyridyl alcohols and bipyridylalcohols were synthesized from the chiral pool for future usein asymmetric catalysis. Lithiated pyridines were reacted withseveral chiral electrophiles, yielding diastereomeric mixturesthat could be separated without the use of resolutiontechniques....

  15. Worst Asymmetrical Short-Circuit Current

    DEFF Research Database (Denmark)

    Arana Aristi, Iván; Holmstrøm, O; Grastrup, L

    2010-01-01

    In a typical power plant, the production scenario and the short-circuit time were found for the worst asymmetrical short-circuit current. Then, a sensitivity analysis on the missing generator values was realized in order to minimize the uncertainty of the results. Afterward the worst asymmetrical...

  16. Renewable resource management under asymmetric information

    DEFF Research Database (Denmark)

    Jensen, Frank; Andersen, Peder; Nielsen, Max

    2013-01-01

    Asymmetric information between fishermen and the regulator is important within fisheries. The regulator may have less information about stock sizes, prices, costs, effort, productivity and catches than fishermen. With asymmetric information, a strong analytical tool is principal-agent analysis. I...

  17. Gases in molten salts

    CERN Document Server

    Tomkins, RPT

    1991-01-01

    This volume contains tabulated collections and critical evaluations of original data for the solubility of gases in molten salts, gathered from chemical literature through to the end of 1989. Within the volume, material is arranged according to the individual gas. The gases include hydrogen halides, inert gases, oxygen, nitrogen, hydrogen, carbon dioxide, water vapor and halogens. The molten salts consist of single salts, binary mixtures and multicomponent systems. Included also, is a special section on the solubility of gases in molten silicate systems, focussing on slags and fluxes.

  18. Condensation on Slippery Asymmetric Bumps

    CERN Document Server

    Park, Kyoo-Chul; He, Neil; Aizenberg, Joanna

    2015-01-01

    Bumps are omnipresent from human skin to the geological structures on planets, which offer distinct advantages in numerous phenomena including structural color, drag reduction, and extreme wettability. Although the topographical parameters of bumps such as radius of curvature of convex regions significantly influence various phenomena including anti-reflective structures and contact time of impacting droplets, the effect of the detailed bump topography on growth and transport of condensates have not been clearly understood. Inspired by the millimetric bumps of the Namib Desert beetle, here we report the identified role of radius of curvature and width of bumps with homogeneous surface wettability in growth rate, coalescence and transport of water droplets. Further rational design of asymmetric convex topography and synergetic combination with slippery coating simultaneously enable self-transport, leading to unseen five-fold higher growth rate and an order of magnitude faster shedding time of droplets compared...

  19. Wetting and evaporation of salt-water nanodroplets: A molecular dynamics investigation.

    Science.gov (United States)

    Zhang, Jun; Borg, Matthew K; Sefiane, Khellil; Reese, Jason M

    2015-11-01

    We employ molecular dynamics simulations to study the wetting and evaporation of salt-water nanodroplets on platinum surfaces. Our results show that the contact angle of the droplets increases with the salt concentration. To verify this, a second simulation system of a thin salt-water film on a platinum surface is used to calculate the various surface tensions. We find that both the solid-liquid and liquid-vapor surface tensions increase with salt concentration and as a result these cause an increase in the contact angle. However, the evaporation rate of salt-water droplets decreases as the salt concentration increases, due to the hydration of salt ions. When the water molecules have all evaporated from the droplet, two forms of salt crystals are deposited, clump and ringlike, depending on the solid-liquid interaction strength and the evaporation rate. To form salt crystals in a ring, it is crucial that there is a pinned stage in the evaporation process, during which salt ions can move from the center to the rim of the droplets. With a stronger solid-liquid interaction strength, a slower evaporation rate, and a higher salt concentration, a complete salt crystal ring can be deposited on the surface.

  20. Wetting and evaporation of salt-water nanodroplets: A molecular dynamics investigation

    Science.gov (United States)

    Zhang, Jun; Borg, Matthew K.; Sefiane, Khellil; Reese, Jason M.

    2015-11-01

    We employ molecular dynamics simulations to study the wetting and evaporation of salt-water nanodroplets on platinum surfaces. Our results show that the contact angle of the droplets increases with the salt concentration. To verify this, a second simulation system of a thin salt-water film on a platinum surface is used to calculate the various surface tensions. We find that both the solid-liquid and liquid-vapor surface tensions increase with salt concentration and as a result these cause an increase in the contact angle. However, the evaporation rate of salt-water droplets decreases as the salt concentration increases, due to the hydration of salt ions. When the water molecules have all evaporated from the droplet, two forms of salt crystals are deposited, clump and ringlike, depending on the solid-liquid interaction strength and the evaporation rate. To form salt crystals in a ring, it is crucial that there is a pinned stage in the evaporation process, during which salt ions can move from the center to the rim of the droplets. With a stronger solid-liquid interaction strength, a slower evaporation rate, and a higher salt concentration, a complete salt crystal ring can be deposited on the surface.

  1. Synthesis of Reduced Graphene Oxide-Modified LiMn0.75Fe0.25PO4 Microspheres by Salt-Assisted Spray Drying for High-Performance Lithium-Ion Batteries

    Science.gov (United States)

    Kim, Myeong-Seong; Kim, Hyun-Kyung; Lee, Suk-Woo; Kim, Dong-Hyun; Ruan, Dianbo; Chung, Kyung Yoon; Lee, Sang Hyun; Roh, Kwang Chul; Kim, Kwang-Bum

    2016-05-01

    Microsized, spherical, three-dimensional (3D) graphene-based composites as electrode materials exhibit improved tap density and electrochemical properties. In this study, we report 3D LiMn0.75Fe0.25PO4/reduced graphene oxide microspheres synthesized by one-step salt-assisted spray drying using a mixed solution containing a precursor salt and graphene oxide and a subsequent heat treatment. During this process, it was found that the type of metal salt used has significant effects on the morphology, phase purity, and electrochemical properties of the synthesized samples. Furthermore, the amount of the chelating agent used also affects the phase purity and electrochemical properties of the samples. The composite exhibited a high tap density (1.1 g cm‑3) as well as a gravimetric capacity of 161 mA h g‑1 and volumetric capacity of 281 mA h cm‑3 at 0.05 C-rate. It also exhibited excellent rate capability, delivering a discharge capacity of 90 mA h g‑1 at 60 C-rate. Furthermore, the microspheres exhibited high energy efficiency and good cyclability, showing a capacity retention rate of 93% after 1000 cycles at 10 C-rate.

  2. Chemical markers for sea salt in IMPROVE aerosol data

    Science.gov (United States)

    White, Warren H.

    The Interagency Monitoring of PROtected Visual Environments (IMPROVE) network monitors chemically speciated fine-particle concentrations at about 170 rural or remote sites in the United States, including several in coastal settings. Sea salt is a major component of marine aerosols, and can have significant optical effects on both global and local scales. Sodium is the most commonly employed chemical marker for sea salt, but the ion is not a target of IMPROVE's routine chromatography and the element is poorly detected by IMPROVE's routine X-ray fluorescence analysis. This paper examines data from six coastal sites where sea salt is abundant, to identify more reliable signatures of fresh sea salt in routine IMPROVE data. The chloride ion measurement, by ion chromatography on a Nylon filter sampling behind a carbonate denuder, appears to represent the total concentration of this reactive species at the selected sites. It is shown to be a good predictor of conserved sea salt markers such as non-crustal strontium, calcium and potassium, as well as the portion of gravimetric mass not explained by terrestrial fractions. These conclusions may not extend to other locations where sea salt is a smaller and more aged fraction of the aerosol mix.

  3. Crystal structures of triazine-3-thione derivatives by reaction with copper and cobalt salts.

    Science.gov (United States)

    López-Torres, Elena; Mendiola, Maria Antonia; Pastor, César J

    2006-04-03

    The reaction of 5-methoxy-5,6-diphenyl-4,5-dihydro-2H-[1,2,4]triazine-3-thione L1H2OCH3 with copper(II) chloride leads to the formation of an organic molecule L2 containing two triazine rings linked by a new S-S bond. A binuclear copper(II) complex, 1, containing L1 is also isolated. The reaction of L1H2OCH3 with copper(I) chloride yields a hexanuclear cluster of copper(I), 2, in which the copper atoms form a distorted octahedron with the ligand L1 acting as an NS chelate and sulfur bridge, giving to the copper ion a trigonal geometry by one N and two S atoms. In any reaction of the disulfide L2 with metal salts, complexes containing this molecule are isolated. Reactions with copper(I) and copper(II) chloride and nickel(II) and cadmium(II) nitrate produce the S-S bond cleavage, giving complexes containing the triazine L1 behaving as the NS anion, which show spectroscopic characteristics identical with those formed by reaction with L1H2OCH3. However, the reaction with cobalt(II) nitrate gives a low-spin octahedral cobalt(III) complex, in which an asymmetric rupture of the disulfide L2 has been produced, giving an unexpected complex with a new ligand and keeping the S-S bond.

  4. Crystal structures and hydrogen bonding in the morpholinium salts of four phenoxyacetic acid analogues

    Directory of Open Access Journals (Sweden)

    Graham Smith

    2015-11-01

    Full Text Available The anhydrous salts morpholinium (tetrahydro-2-H-1,4-oxazin-4-ium phenoxyacetate, C4H10NO+·C8H7O3−, (I, morpholinium (4-fluorophenoxyacetate, C4H10NO+·C8H6 FO3−, (II, and isomeric morpholinium (3,5-dichlorophenoxyacetate (3,5-D, (III, and morpholinium (2,4-dichlorophenoxyacetic acid (2,4-D, C4H10NO+·C8H5Cl2O3−, (IV, have been determined and their hydrogen-bonded structures are described. In the crystals of (I, (III and (IV, one of the the aminium H atoms is involved in a three-centre asymmetric cation–anion N—H...O,O′ R12(4 hydrogen-bonding interaction with the two carboxyl O-atom acceptors of the anion. With the structure of (II, the primary N—H...O interaction is linear. In the structures of (I, (II and (III, the second N—H...Ocarboxyl hydrogen bond generates one-dimensional chain structures extending in all cases along [100]. With (IV, the ion pairs are linked though inversion-related N—H...O hydrogen bonds [graph set R42(8], giving a cyclic heterotetrameric structure.

  5. Salt-free vesicle-phases and their template effect

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Researches on the construction, structure, and formation of vesicles formed from surfactants have attracted great attention from colloid and interface chemists. The vesicles formed from salt-free cationic-anionic surfactant systems are very different from those with excess salts, having many particular properties. In this paper, we introduce the properties of vesicles prepared from salt-free surfactant systems, according to our own results, especially the vesicles formed from surfactants with divalent metal ions as counterions in aqueous solutions and room temperature ionic liquids. Moreover, the primary results on template effect of the metal-ligand vesicles have also been summarized.

  6. Gene Response to Salt Stress in Populus euphratica

    Institute of Scientific and Technical Information of China (English)

    Shen Xin; Thomas Teichmenn; Wang Yiqin; Bai Genben; Yu Guangjun; Wang Shasheng

    2003-01-01

    Through construction of a subtracted cDNA library and library screening, a number of salt-induced cDNA fragmentshave been cloned from Populus euphratica. Based on the results of DNA sequencing and Northern analysis, the gene response ofPopulus euphratica to salt stress is discussed. It is indicated that in response to salt treatment the transcription level for some genes ofPopulus euphratica increases by about 1.5 times and significant difference between the responses to osmotic stress and to ion stresshas been observed in gene activity.

  7. Apparatus and method for stripping tritium from molten salt

    Energy Technology Data Exchange (ETDEWEB)

    Holcomb, David E.; Wilson, Dane F.

    2017-02-07

    A method of stripping tritium from flowing stream of molten salt includes providing a tritium-separating membrane structure having a porous support, a nanoporous structural metal-ion diffusion barrier layer, and a gas-tight, nonporous palladium-bearing separative layer, directing the flowing stream of molten salt into contact with the palladium-bearing layer so that tritium contained within the molten salt is transported through the tritium-separating membrane structure, and contacting a sweep gas with the porous support for collecting the tritium.

  8. Ion-Mediated Nucleic Acid Helix-Helix Interactions

    OpenAIRE

    Tan, Zhi-Jie; Chen, Shi-Jie

    2006-01-01

    Salt ions are essential for the folding of nucleic acids. We use the tightly bound ion (TBI) model, which can account for the correlations and fluctuations for the ions bound to the nucleic acids, to investigate the electrostatic free-energy landscape for two parallel nucleic acid helices in the solution of added salt. The theory is based on realistic atomic structures of the helices. In monovalent salt, the helices are predicted to repel each other. For divalent salt, while the mean-field Po...

  9. Synthetic Cathinones ("Bath Salts")

    Science.gov (United States)

    ... and Over-the-Counter Medications Stimulant ADHD Medications: Methylphenidate and Amphetamines Synthetic Cannabinoids Synthetic Cathinones ("Bath Salts") Effects of Drug Abuse Comorbidity: Addiction and Other Mental Disorders Drug Use ...

  10. Plasma and Energetic Particle Behaviors During Asymmetric Magnetic Reconnection at the Magnetopause

    Science.gov (United States)

    Lee, S. H.; Zhang, H.; Zong, Q.-G.; Otto, A.; Sibeck, D. G.; Wang, Y.; Glassmeier, K.-H.; Daly, P.W.; Reme, H.

    2014-01-01

    The factors controlling asymmetric reconnection and the role of the cold plasma population in the reconnection process are two outstanding questions. We present a case study of multipoint Cluster observations demonstrating that the separatrix and flow boundary angles are greater on the magnetosheath than on the magnetospheric side of the magnetopause, probably due to the stronger density than magnetic field asymmetry at this boundary. The motion of cold plasmaspheric ions entering the reconnection region differs from that of warmer magnetosheath and magnetospheric ions. In contrast to the warmer ions, which are probably accelerated by reconnection in the diffusion region near the subsolar magnetopause, the colder ions are simply entrained by ??×?? drifts at high latitudes on the recently reconnected magnetic field lines. This indicates that plasmaspheric ions can sometimes play only a very limited role in asymmetric reconnection, in contrast to previous simulation studies. Three cold ion populations (probably H+, He+, and O+) appear in the energy spectrum, consistent with ion acceleration to a common velocity.

  11. Asymmetric stem cell division: lessons from Drosophila.

    Science.gov (United States)

    Wu, Pao-Shu; Egger, Boris; Brand, Andrea H

    2008-06-01

    Asymmetric cell division is an important and conserved strategy in the generation of cellular diversity during animal development. Many of our insights into the underlying mechanisms of asymmetric cell division have been gained from Drosophila, including the establishment of polarity, orientation of mitotic spindles and segregation of cell fate determinants. Recent studies are also beginning to reveal the connection between the misregulation of asymmetric cell division and cancer. What we are learning from Drosophila as a model system has implication both for stem cell biology and also cancer research.

  12. On-chip asymmetric microcavity optomechanics.

    Science.gov (United States)

    Soltani, Soheil; Hudnut, Alexa W; Armani, Andrea M

    2016-12-26

    High quality factor (Q) optical resonators have enabled rapid growth in the field of cavity-enhanced, radiation pressure-induced optomechanics. However, because research has focused on axisymmetric devices, the observed regenerative excited mechanical modes are similar. In the present work, a strategy for fabricating high-Q whispering gallery mode microcavities with varying degrees of asymmetry is developed and demonstrated. Due to the combination of high optical Q and asymmetric device design, two previously unobserved modes, the asymmetric cantilever and asymmetric crown mode, are demonstrated with sub-mW thresholds for onset of oscillations. The experimental results are in good agreement with computational modeling predictions.

  13. Regenerating a symmetry in asymmetric dark matter.

    Science.gov (United States)

    Buckley, Matthew R; Profumo, Stefano

    2012-01-06

    Asymmetric dark matter theories generically allow for mass terms that lead to particle-antiparticle mixing. Over the age of the Universe, dark matter can thus oscillate from a purely asymmetric configuration into a symmetric mix of particles and antiparticles, allowing for pair-annihilation processes. Additionally, requiring efficient depletion of the primordial thermal (symmetric) component generically entails large annihilation rates. We show that unless some symmetry completely forbids dark matter particle-antiparticle mixing, asymmetric dark matter is effectively ruled out for a large range of masses, for almost any oscillation time scale shorter than the age of the Universe.

  14. Absolute Asymmetric Synthesis Using A Cocrystal Approach

    Institute of Scientific and Technical Information of China (English)

    H.Koshima

    2007-01-01

    1 Results Absolute asymmetric synthesis by means of solid-state reaction of chiral crystals self-assembled from achiral molecules is an attractive and promising methodology for asymmetric synthesis because it is not necessary to employ any external chiral source like a chiral catalyst.In order to design reliably absolute asymmetric syntheses in the solid state,it is inevitable to prepare and predict the formation of chiral crystals from achiral compounds.We have prepared a number of chiral cocrystals co...

  15. Asymmetric dark matter in braneworld cosmology

    Energy Technology Data Exchange (ETDEWEB)

    Meehan, Michael T.; Whittingham, Ian B., E-mail: Michael.Meehan@my.jcu.edu.au, E-mail: Ian.Whittingham@jcu.edu.au [School of Engineering and Physical Sciences, James Cook University, Townsville, 4811 Australia (Australia)

    2014-06-01

    We investigate the effect of a braneworld expansion era on the relic density of asymmetric dark matter. We find that the enhanced expansion rate in the early universe predicted by the Randall-Sundrum II (RSII) model leads to earlier particle freeze-out and an enhanced relic density. This effect has been observed previously by Okada and Seto (2004) for symmetric dark matter models and here we extend their results to the case of asymmetric dark matter. We also discuss the enhanced asymmetric annihilation rate in the braneworld scenario and its implications for indirect detection experiments.

  16. Enantiopure sulfoxides: recent applications in asymmetric synthesis.

    Science.gov (United States)

    Carreño, M Carmen; Hernández-Torres, Gloria; Ribagorda, María; Urbano, Antonio

    2009-11-07

    Sulfoxides are nowadays recognised as powerful chiral auxiliaries that may participate in a wide range of asymmetric reactions. Their high configurational stability, the existence of several efficient methods allowing the access to both configurations as well as their synthetic versatility are characteristic features offering a tremendous potential to develop new applications. Significant recent advances leading to high asymmetric inductions in carbon-carbon and carbon-oxygen bond forming reactions, and applications of homochiral sulfoxides to atroposelective synthesis and asymmetric catalysis are discussed. New uses of sulfoxides in the design of chiroptical switches are also shown.

  17. Effective salt criteria in callus-cultured tomato genotypes.

    Science.gov (United States)

    Dogan, Mahmut; Tipirdamaz, Rukiye; Demir, Yavuz

    2010-01-01

    Na+, Cl-, K+, Ca2+, and proline contents, the rate of lipid peroxidation level in terms of malondialdehyde (MDA) and chlorophyll content, and the changes in the activity of antioxidant enzymes, such as superoxide dismutase (SOD: EC 1.15.1.1), catalase (CAT: EC 1.11.1.6), ascorbate peroxidase (APX: EC 1.11.1.11), and glutathione reductase (GR: EC 1.6.4.2), in tissues of five tomato cultivars in salt tolerance were investigated in a callus culture. The selection of effective parameters used in these tomato genotypes and to find out the use of in vitro tests in place of in vivo salt tolerance tests were investigated. As a material, five different tomato genotypes during a 10-day time period were used, and 150 mM NaCl was applied at callus plant tissue. The exposure to NaCl induced a significant increase in MDA content in both salt-resistant and salt-sensitive cultivars. But the MDA content was higher in salt-sensitive cultivars. The chlorophyll content was more decreased in salt-sensitive than in salt-resistant ones. The proline amount was more increased in salt-sensitive than in salt-resistant ones. It has been reported that salt-tolerant plants, besides being able to regulate the ion and water movements, also exhibit a strong antioxidative enzyme system for effective removal of ROS. The degree of damage depends on the balance between the formation of ROS and its removal by the antioxidative scavenging system that protects against them. Exclusion or inclusion of Na+, Cl-, K+, and Ca2+, antioxidant enzymes and MDA concentration play a key protective role against stress, and this feature at the callus plant tissue used as an identifier for tolerance to salt proved to be an effective criterion.

  18. Asymmetric dark matter bound state

    Science.gov (United States)

    Bi, Xiao-Jun; Kang, Zhaofeng; Ko, P.; Li, Jinmian; Li, Tianjun

    2017-02-01

    We propose an interesting framework for asymmetric scalar dark matter (ADM), which has novel collider phenomenology in terms of an unstable ADM bound state (ADMonium) produced via Higgs portals. ADMonium is a natural consequence of the basic features of ADM: the (complex scalar) ADM is charged under a dark local U (1 )d symmetry which is broken at a low scale and provides a light gauge boson X . The dark gauge coupling is strong and then ADM can annihilate away into X -pair effectively. Therefore, the ADM can form a bound state due to its large self-interaction via X mediation. To explore the collider signature of ADMonium, we propose that ADM has a two-Higgs doublet portal. The ADMonium can have a sizable mixing with the heavier Higgs boson, which admits a large cross section of ADMonium production associated with b b ¯. The resulting signature at the LHC depends on the decays of X . In this paper we consider a case of particular interest: p p →b b ¯ +ADMonium followed by ADMonium→2 X →2 e+e- where the electrons are identified as (un)converted photons. It may provide a competitive explanation to heavy di-photon resonance searches at the LHC.

  19. Twin Higgs Asymmetric Dark Matter.

    Science.gov (United States)

    García García, Isabel; Lasenby, Robert; March-Russell, John

    2015-09-18

    We study asymmetric dark matter (ADM) in the context of the minimal (fraternal) twin Higgs solution to the little hierarchy problem, with a twin sector with gauged SU(3)^{'}×SU(2)^{'}, a twin Higgs doublet, and only third-generation twin fermions. Naturalness requires the QCD^{'} scale Λ_{QCD}^{'}≃0.5-20  GeV, and that t^{'} is heavy. We focus on the light b^{'} quark regime, m_{b^{'}}≲Λ_{QCD}^{'}, where QCD^{'} is characterized by a single scale Λ_{QCD}^{'} with no light pions. A twin baryon number asymmetry leads to a successful dark matter (DM) candidate: the spin-3/2 twin baryon, Δ^{'}∼b^{'}b^{'}b^{'}, with a dynamically determined mass (∼5Λ_{QCD}^{'}) in the preferred range for the DM-to-baryon ratio Ω_{DM}/Ω_{baryon}≃5. Gauging the U(1)^{'} group leads to twin atoms (Δ^{'}-τ^{'}[over ¯] bound states) that are successful ADM candidates in significant regions of parameter space, sometimes with observable changes to DM halo properties. Direct detection signatures satisfy current bounds, at times modified by dark form factors.

  20. Force on an Asymmetric Capacitor

    CERN Document Server

    Bahder, T B; Bahder, Thomas B.; Fazi, Chris

    2002-01-01

    When a high voltage (~30 kV) is applied to a capacitor whose electrodes have different physical dimensions, the capacitor experiences a net force toward the smaller electrode (Biefeld-Brown effect). We have verified this effect by building four capacitors of different shapes. The effect may have applications to vehicle propulsion and dielectric pumps. We review the history of this effect briefly through the history of patents by Thomas Townsend Brown. At present, the physical basis for the Biefeld-Brown effect is not understood. The order of magnitude of the net force on the asymmetric capacitor is estimated assuming two different mechanisms of charge conduction between its electrodes: ballistic ionic wind and ionic drift. The calculations indicate that ionic wind is at least three orders of magnitude too small to explain the magnitude of the observed force on the capacitor. The ionic drift transport assumption leads to the correct order of magnitude for the force, however, it is difficult to see how ionic dr...

  1. Asymmetric total synthesis of vindoline.

    Science.gov (United States)

    Kato, Daisuke; Sasaki, Yoshikazu; Boger, Dale L

    2010-03-24

    A concise asymmetric total synthesis of (-)-vindoline (1) is detailed based on a tandem intramolecular [4+2]/[3+2] cycloaddition cascade of a 1,3,4-oxadiazole inspired by the natural product structure, in which the tether linking the initiating dienophile and oxadiazole bears a chiral substituent that controls the facial selectivity of the initiating Diels-Alder reaction and sets absolute stereochemistry of the remaining six stereocenters in the cascade cycloadduct. This key reaction introduces three rings and four C-C bonds central to the pentacyclic ring system setting all six stereocenters and introducing essentially all the functionality found in the natural product in a single step. Implementation of the approach also required the development of a unique ring expansion reaction to provide a six-membered ring suitably functionalized for introduction of the Delta (6, 7)-double bond found in the core structure of vindoline and defined our use of a protected hydroxymethyl group as the substituent used to control the stereochemical course of the cycloaddition cascade.

  2. A single pump cycling-column-switching technique coupled with homemade high exchange capacity columns for the determination of iodate in iodized edible salt by ion chromatography with UV detection.

    Science.gov (United States)

    Huang, Zhongping; Subhani, Qamar; Zhu, Zuoyi; Guo, Weiqiang; Zhu, Yan

    2013-08-15

    A single pump cycling-column-switching technique has been developed for the iodate analysis in edible salt. Homemade high exchange capacity columns were adopted for the separation of iodate and chloride. Iodate could be retained and concentrated in a homemade concentrator column after eluents passing through the suppressor. With UV detection, iodate exhibited satisfactory linearity in the range of 0.1-10.0 mg/L with a correlation coefficient of 0.9996. The detection limit (LOD) was 45.53 μg/L, based on the signal-to-noise ratio of 3 (S/N=3) and a 100 μL injection volume. Relative standard deviations (RSDs) for retention time, peak area and peak height were all less than 2.1%. Recoveries of added iodate were in the range of 98.4-101.6% for the spiked samples. The quantitative determination of iodate in edible salt was accomplished by this column-switching technique, without any pretreatment and interference. The results on six samples were statistically compared with results determined by conventional titrimetric method.

  3. HIGH YIELD AND RAPID SYNTHESES METHODS FOR PRODUCING METALLO-ORGANIC SALTS

    DEFF Research Database (Denmark)

    2005-01-01

    A new method for preparing salts of metal cations and organic acids, especially divalent salts of alkaline earth metal ions from group II of the periodic system and carboxylic acids. The method comprising the use of a high temperature (about 90° or more) and, optionally. high pressure, in order t...... to obtain a higher yield, purity and faster reaction speed than obtained with known synthesis methods. In particular, the present invention relates to the production of strontium salts of carboxylic acids. Novel strontium salts are also provided by the present method.......A new method for preparing salts of metal cations and organic acids, especially divalent salts of alkaline earth metal ions from group II of the periodic system and carboxylic acids. The method comprising the use of a high temperature (about 90° or more) and, optionally. high pressure, in order...

  4. Salt treatment Fukushima

    Energy Technology Data Exchange (ETDEWEB)

    Schaefer, Stefan [NUKEM Technologies GmbH, Alzenau (Germany)

    2013-07-01

    The Task of NUKEM Technologies GmbH is to develop a technical solution for the treatment of salt containing effluents at Fukushima Daiichi. The target of the treatment is a solidified product suitable for the safe storage on site. Therefore, NUKEM investigated several technologies (direct cementation, drying and storage, drying and subsequent cementation) in order to find a fit for purpose solution. The following tasks have been considered: (a) Mechanical strength and homogeneity of the product; (b) Cost efficient solution (cost for the drying system vs. reduced amount of storage containers); (c) Proven technology; (d) On site storage. NUKEM made some practical test in parallel with different recipes. The aim was to embed as much as possible salt quantity into the cement matrix, but still meet the requested mechanical strength and required homogeneity. As a result NUKEM recommended to apply the following technologies (a) a drying system, to produce a dry salt product (b) a cementation facility, to generate a homogeneous salt/cement matrix (c) a filling station with attached CMS (Container measuring station) to fill the resulting cement/salt matrix into containers suitable for the storage at Fukushima Daiichi. (orig.)

  5. A novel asymmetric synthesis of cinacalcet hydrochloride

    OpenAIRE

    Arava, Veera R; Laxminarasimhulu Gorentla; Pramod K. Dubey

    2012-01-01

    A novel route to asymmetric synthesis of cinacalcet hydrochloride by the application of (R)-tert-butanesulfinamide and regioselective N-alkylation of the naphthyl ethyl sulfinamide intermediate is described.

  6. A novel asymmetric synthesis of cinacalcet hydrochloride

    Directory of Open Access Journals (Sweden)

    Veera R. Arava

    2012-08-01

    Full Text Available A novel route to asymmetric synthesis of cinacalcet hydrochloride by the application of (R-tert-butanesulfinamide and regioselective N-alkylation of the naphthyl ethyl sulfinamide intermediate is described.

  7. A novel asymmetric synthesis of cinacalcet hydrochloride

    Science.gov (United States)

    Gorentla, Laxminarasimhulu; Dubey, Pramod K

    2012-01-01

    Summary A novel route to asymmetric synthesis of cinacalcet hydrochloride by the application of (R)-tert-butanesulfinamide and regioselective N-alkylation of the naphthyl ethyl sulfinamide intermediate is described. PMID:23019473

  8. Catalytic Asymmetric Synthesis of Phosphine Boronates

    NARCIS (Netherlands)

    Hornillos, Valentin; Vila, Carlos; Otten, Edwin; Feringa, Ben L.

    2015-01-01

    The first catalytic enantioselective synthesis of ambiphilic phosphine boronate esters is presented. The asymmetric boration of ,-unsaturated phosphine oxides catalyzed by a copper bisphosphine complex affords optically active organoboronate esters that bear a vicinal phosphine oxide group in good y

  9. Asymmetric Swiss-cheese brane-worlds

    CERN Document Server

    Gergely, L A; K\\'{e}p\\'{\\i}r\\'{o}, Ibolya

    2006-01-01

    We consider Swiss-cheese brane universes embedded asymmetrically into the bulk. Neither the junction conditions between the Schwarzschild spheres and the sorrounding Friedmann brane regions with cosmological constant $\\Lambda $, nor the evolution of the scale factor are changed with respect to the symmetric case. The universe expands and decelerates forever. The asymmetry however has a drastic influence on the evolution of the cosmological fluid. Instead of the two branches of the symmetric case, in the asymmetric case four branches emerge. Moreover, the future pressure singularity arising in the symmetric case only for huge values of $\\Lambda $ becomes quite generic in the asymmetric case. Such pressure singularities emerge also when $\\Lambda=0$ is set. Then they are due entirely to the asymmetric embedding. For generic values of $\\Lambda $ we introduce a critical value of a suitably defined asymmetry parameter, which separates Swiss-cheese cosmologies with and without pressure singularities.

  10. Congenital asymmetric crying face: a case report

    Directory of Open Access Journals (Sweden)

    Semra Kara

    2011-12-01

    Full Text Available Congenital asymmetric crying face is an anomalia caused by unilateral absence or weakness of depressor anguli oris muscle The major finding of the disease is the absence or weakness in the outer and lower movement of the commissure during crying. The other expression muscles are normal and the face is symmetric at rest. The asymmetry in congenital asymmetric crying face is most evident during infancy but decreases by age. Congenital asymmetric crying face can be associated with cervicofacial, musclebone, respiratory, genitourinary and central nervous system anomalia. It is diagnosed by physical examination. This paper presents a six days old infant with Congenital asymmetric crying face and discusses the case in terms of diagnosis and disease features.

  11. Asymmetric cryptography based on wavefront sensing.

    Science.gov (United States)

    Peng, Xiang; Wei, Hengzheng; Zhang, Peng

    2006-12-15

    A system of asymmetric cryptography based on wavefront sensing (ACWS) is proposed for the first time to our knowledge. One of the most significant features of the asymmetric cryptography is that a trapdoor one-way function is required and constructed by analogy to wavefront sensing, in which the public key may be derived from optical parameters, such as the wavelength or the focal length, while the private key may be obtained from a kind of regular point array. The ciphertext is generated by the encoded wavefront and represented with an irregular array. In such an ACWS system, the encryption key is not identical to the decryption key, which is another important feature of an asymmetric cryptographic system. The processes of asymmetric encryption and decryption are formulized mathematically and demonstrated with a set of numerical experiments.

  12. DOES VOLATILITY RESPOND ASYMMETRIC TO PAST SHOCKS?

    OpenAIRE

    Claudiu Botoc

    2014-01-01

    The main aim of the paper is to examine if the stock market volatility exhibits asymmetric or an asymmetric response to past shocks, for certain CEE countries (Romania,Hungary, Bulgaria, Poland) over the period May 2004 - September 2014. For the stock marketsfrom East Europe the results are in line with the symmetric volatility, i.e. volatility is similaraffected by both positive and negative returns with the same magnitude. For the stock marketsfrom Central Europe the results are consistent ...

  13. Performance and cost characteristics of multi-electron transfer, common ion exchange non-aqueous redox flow batteries

    Science.gov (United States)

    Laramie, Sydney M.; Milshtein, Jarrod D.; Breault, Tanya M.; Brushett, Fikile R.; Thompson, Levi T.

    2016-09-01

    Non-aqueous redox flow batteries (NAqRFBs) have recently received considerable attention as promising high energy density, low cost grid-level energy storage technologies. Despite these attractive features, NAqRFBs are still at an early stage of development and innovative design techniques are necessary to improve performance and decrease costs. In this work, we investigate multi-electron transfer, common ion exchange NAqRFBs. Common ion systems decrease the supporting electrolyte requirement, which subsequently improves active material solubility and decreases electrolyte cost. Voltammetric and electrolytic techniques are used to study the electrochemical performance and chemical compatibility of model redox active materials, iron (II) tris(2,2‧-bipyridine) tetrafluoroborate (Fe(bpy)3(BF4)2) and ferrocenylmethyl dimethyl ethyl ammonium tetrafluoroborate (Fc1N112-BF4). These results help disentangle complex cycling behavior observed in flow cell experiments. Further, a simple techno-economic model demonstrates the cost benefits of employing common ion exchange NAqRFBs, afforded by decreasing the salt and solvent contributions to total chemical cost. This study highlights two new concepts, common ion exchange and multi-electron transfer, for NAqRFBs through a demonstration flow cell employing model active species. In addition, the compatibility analysis developed for asymmetric chemistries can apply to other promising species, including organics, metal coordination complexes (MCCs) and mixed MCC/organic systems, enabling the design of low cost NAqRFBs.

  14. Salt reduction and hypertension in China: a concise state-of-the-art review

    OpenAIRE

    Liu, Yue; Li, Huiyan; Hong, Siting; Yin, Xinhua

    2015-01-01

    Hypertension (HTN) and its cardiovascular complications such as stroke and heart failure are a serious public health problem around the world. A growing number of studies confirm that salt plays an important role in the development of HTN. Increasing intake of salt leads to abnormal transport of sodium ions at the cellular level with activation of the sympathetic nervous system and renin-angiotensin-aldosterone system. Studies have shown that salt restriction can reduce blood pressure (BP) in...

  15. Computational simulations of asymmetric fluxes of large molecules through gap junction channel pores.

    Science.gov (United States)

    Mondal, Abhijit; Appadurai, Daniel A; Akoum, Nazem W; Sachse, Frank B; Moreno, Alonso P

    2017-01-07

    Gap junction channels are formed out of connexin isoforms, which enable molecule and ion selective diffusion amongst neighboring cells. HeLa cells expressing distinct connexins (Cx) allow the formation of heterotypic channels, where we observed a molecular charge-independent preferential flux of large fluorescent molecules in the Cx45 to Cx43 direction. We hypothesize that the pore's shape is a significant factor along-side charge and transjunctional voltages for this asymmetric flux. To test this hypothesis, we developed a 3D computational model simulating Brownian diffusion of large molecules in a gap junction channel pore. The basic pore contour was derived from x-ray crystallographic structures of Cx43 and Cx26 and approximated using basic geometric shapes. Lucifer yellow dye molecules and cesium counter-ions were modeled as spheres using their respective Stokes radii. Our simulation results from simple diffusion and constant concentration gradient experiments showed that only charged particles yield asymmetric fluxes in heterotypic pores. While increasing the inner mouth size resulted in a near-quadratic rise in flux, the rise was asymptotic for outer mouth radii increase. Probability maps and average force per particle per pore section explain the asymmetric flux with variation in pore shape. Furthermore, the simulation results are in agreement with our in vitro experimental results with HeLa cells in Cx43-Cx45 heterotypic configurations. The presence of asymmetric fluxes can help us to understand effects of the molecular structure of the pore and predict potential differences in vivo.

  16. Nanofriction in cold ion traps.

    Science.gov (United States)

    Benassi, A; Vanossi, A; Tosatti, E

    2011-01-01

    Sliding friction between crystal lattices and the physics of cold ion traps are so far non-overlapping fields. Two sliding lattices may either stick and show static friction or slip with dynamic friction; cold ions are known to form static chains, helices or clusters, depending on the trapping conditions. Here we show, based on simulations, that much could be learnt about friction by sliding, through, for example, an electric field, the trapped ion chains over a corrugated potential. Unlike infinite chains, in which the theoretically predicted Aubry transition to free sliding may take place, trapped chains are always pinned. Yet, a properly defined static friction still vanishes Aubry-like at a symmetric-asymmetric structural transition, found for decreasing corrugation in both straight and zig-zag trapped chains. Dynamic friction is also accessible in ringdown oscillations of the ion trap. Long theorized static and dynamic one-dimensional friction phenomena could thus become accessible in future cold ion tribology.

  17. Mechanism for salt scaling

    Science.gov (United States)

    Valenza, John J., II

    Salt scaling is superficial damage caused by freezing a saline solution on the surface of a cementitious body. The damage consists of the removal of small chips or flakes of binder. The discovery of this phenomenon in the early 1950's prompted hundreds of experimental studies, which clearly elucidated the characteristics of this damage. In particular it was shown that a pessimum salt concentration exists, where a moderate salt concentration (˜3%) results in the most damage. Despite the numerous studies, the mechanism responsible for salt scaling has not been identified. In this work it is shown that salt scaling is a result of the large thermal expansion mismatch between ice and the cementitious body, and that the mechanism responsible for damage is analogous to glue-spalling. When ice forms on a cementitious body a bi-material composite is formed. The thermal expansion coefficient of the ice is ˜5 times that of the underlying body, so when the temperature of the composite is lowered below the melting point, the ice goes into tension. Once this stress exceeds the strength of the ice, cracks initiate in the ice and propagate into the surface of the cementitious body, removing a flake of material. The glue-spall mechanism accounts for all of the characteristics of salt scaling. In particular, a theoretical analysis is presented which shows that the pessimum concentration is a consequence of the effect of brine pockets on the mechanical properties of ice, and that the damage morphology is accounted for by fracture mechanics. Finally, empirical evidence is presented that proves that the glue-small mechanism is the primary cause of salt scaling. The primary experimental tool used in this study is a novel warping experiment, where a pool of liquid is formed on top of a thin (˜3 mm) plate of cement paste. Stresses in the plate, including thermal expansion mismatch, result in warping of the plate, which is easily detected. This technique revealed the existence of

  18. A Comparative Study on Salt Tolerance of Wild,Cultivated and their Hybrid F1 Tomato Seedlings Based on the Ion Homeostasis%基于离子稳态的野生与栽培番茄及其杂交F1的耐盐性差异

    Institute of Scientific and Technical Information of China (English)

    敖雁; 管永祥; 孙云贺; 彭益全; 吴昊; 乔燕; 郑青松

    2016-01-01

    An experiment was conducted to study effects of salinity,varying in level,50,100 or 200 mmol L-1 NaCl,on plant growth,ion absorption and distribution of wild tomato Solanum pimpinellifolium (WT),cultivated tomato(S. esculentum)(CT)and their hybrid F1 generation. Results showed that dry weight(DW)of the three tomato varieties decreased significantly under salt stress,either 50,100 or 200 mmol L-1NaCl,displaying a descending order of CT>WT> F1. With rising salt stress,Na+ content increased,while K+ content decreased significantly in all the tomato plants. Besides,under salt stress,K+/Na+ decreased significantly in all the tomato plants and the decreases in the plants,regardless of variety, were similar in extent. With rising salt stress,the roots of the plants of either variety enhanced their K+ or Na+ selectivity ratio(SK,Na),but the enhancement varied slightly in extent with variety,showing an order of WT> F1>CT. However,salt stress decreased stem SK,Na in all the tomato plants by a similar degree. But with rising salt stress,the drop in CT was much bigger than that in F1. Salt stress increased leaf SK,Na of all the tomato plants,but with rising salt stress,leaf SK,Na declined in WT,while it kept increasing gradually in CT and F1 and the rise in F1 was more significant than that in CT. To sum up,the F1 generation is similar to its wild parents in maintaining ion balance,especially in their leaves,which makes F1 generation better in growth and higher in salt tolerance than its parents.%以野生番茄-醋栗番茄D4-101(Solanum pimpinellifolium)(WT)、自交系番茄栽培种7818D(S. esculentum)(CT)及二者杂交产生的F1代品系为材料,探讨50、100及200 mmol L-1 NaCl胁迫处理对番茄生物量和离子吸收分配的影响。结果表明:盐胁迫下,植株干重的降幅由大到小依次是:CT>WT>F1。随着盐胁迫程度加大,三个品种(系)Na+含量均增高,而K+含量显著降低。盐胁迫处理下三个

  19. Some Physiological Responses of Chinese Iris to Salt Stress

    Institute of Scientific and Technical Information of China (English)

    BAI Wen-Bo; LI Pin-Fang; LI Bao-Guo; H. FUJIYAMA; FAN Fen-Cheng

    2008-01-01

    Chinese iris (Iris lactea Pall. Var. Chinensis (Fisch) Koidz.), a robust iridaceous plant, is widesprcad in arid and semiarid regions with high salinity. However, the mechanism of its salt tolerance is not well understood. In this study,plant growth, water status, content and distribution of inorganic ions, cell membrane permeability, and proline content of I. Lactea under salt stress were investigated using nutrient solutions with six NaCl concentrations ranging from 0 to 350 mmol L-1. The results indicated that the biomass, height, fresh weight, K+ content, and K+/Na+ and Ca2+/Na+ratios decreased with increasing NaCl stress, whereas plant water deficit and contents of Na+ and Cl- increased with increasing NaCl stress. In all salt treatments, water deficit of shoots was found to be higher than that of roots and had a positive correlation with salt concentration. When the NaCl concentration was less than 280 mmol L-1, the ion absorption selectivity ratio and the transportation selectivity ratio sharply increased with increasing NaCl stress. Under medium salt stress, I. Lactea exhibited a strong K+ selective absorption and the transportation of K+ from roots to shoots increased, whereas Na+ was not transported and was mostly retained in roots. The plants were able to maintain osmotic adjustment through the accumulation of Na+, Cl-, and proline. On the basis of its biomass production under salt stress,I. Lactea could be considered as a facultative halophyte.

  20. Enhanced assymetrical noradrenergic transmission in the olfactory bulb of deoxycorticosterone acetate-salt hypertensive rats.

    Science.gov (United States)

    Abramoff, Tamara; Guil, María J; Morales, Vanina P; Hope, Sandra I; Soria, Celeste; Bianciotti, Liliana G; Vatta, Marcelo S

    2013-10-01

    The ablation of olfactory bulb induces critical changes in dopamine, and monoamine oxidase activity in the brain stem. Growing evidence supports the participation of this telencephalic region in the regulation blood pressure and cardiovascular activity but little is known about its contribution to hypertension. We have previously reported that in the olfactory bulb of normotensive rats endothelins enhance noradrenergic activity by increasing tyrosine hydroxylase activity and norepinephrine release. In the present study we sought to establish the status of noradrenergic activity in the olfactory bulb of deoxycorticosterone acetate (DOCA)-salt hypertensive rats. Different steps in norepinephrine transmission including tyrosine hydroxylase activity, neuronal norepinephrine release and uptake were assessed in the left and right olfactory bulb of DOCA-salt hypertensive rats. Increased tyrosine hydroxylase activity, and decreased neuronal norepinephrine uptake were observed in the olfactory bulb of DOCA-salt hypertensive rats. Furthermore the expression of tyrosine hydroxylase and its phosphorylated forms were also augmented. Intriguingly, asymmetrical responses between the right and left olfactory bulb of normotensive and hypertensive rats were observed. Neuronal norepinephrine release was increased in the right but not in the left olfactory bulb of DOCA-salt hypertensive rats, whereas non asymmetrical differences were observed in normotensive animals. Present findings indicate that the olfactory bulb of hypertensive rats show an asymmetrical increase in norepinephrine activity. The observed changes in noradrenergic transmission may likely contribute to the onset and/or progression of hypertension in this animal model.

  1. Ion selectivity of graphene nanopores

    OpenAIRE

    Rollings, Ryan C.; Kuan, Aaron T.; Golovchenko, Jene A.

    2016-01-01

    As population growth continues to outpace development of water infrastructure in many countries, desalination (the removal of salts from seawater) at high energy efficiency will likely become a vital source of fresh water. Due to its atomic thinness combined with its mechanical strength, porous graphene may be particularly well-suited for electrodialysis desalination, in which ions are removed under an electric field via ion-selective pores. Here, we show that single graphene nanopores prefer...

  2. Salt Contribution to the Flexibility of Single-stranded Nucleic Acid of Finite Length

    CERN Document Server

    Wang, Feng-Hua; Tan, Zhi-Jie

    2012-01-01

    Nucleic acids are negatively charged macromolecules and their structure properties are strongly coupled to metal ions in solutions. In this paper, the salt effects on the flexibility of single stranded (ss) nucleic acid chain ranging from 12 to 120 nucleotides are investigated systematically by the coarse grained Monte Carlo simulations where the salt ions are considered explicitly and the ss chain is modeled with the virtual bond structural model. Our calculations show that, the increase of ion concentration causes the structural collapse of ss chain and multivalent ions are much more efficient in causing such collapse, and trivalent and small divalent ions can both induce more compact state than a random relaxation state. We found that monovalent, divalent and trivalent ions can all overcharge ss chain, and the dominating source for such overcharging changes from ion exclusion volume effect to ion Coulomb correlations. In addition, the predicted Na and Mg dependent persistence length lp of ss nucleic acid a...

  3. Ion-pair triple helicates and mesocates self-assembled from ditopic 2,2 -bipyridine-bis(urea) ligands and Ni(II) and Fe(II) sulfate salts

    Energy Technology Data Exchange (ETDEWEB)

    Custelcean, Radu [ORNL; Bonnesen, Peter V [ORNL; Roach, Benjamin D [ORNL; Duncan, Nathan C [ORNL

    2012-01-01

    NiSO{sub 4} and FeSO{sub 4} self-assemble with heteroditopic ligands (L) comprising 2,2{prime}-bipyridine and o-phenylene-(bis)urea cation- and anion-binding sites, respectively, into [ML{sub 3}SO{sub 4}] (M = Ni{sup 2+}, Fe{sup 2+}) triple-stranded ion-pair helicates and mesocates.

  4. Development of the asymmetric human

    Science.gov (United States)

    Wolpert, Lewis

    2005-10-01

    Symmetry across the midline is present in many animals, together with the left/right asymmetry of several organs, such as the heart in vertebrates. The development of such asymmetries during embryonic development requires first the specification of the midline and then specification of left/right. One model proposes the transfer of molecular asymmetry to the multicellular level. Nodal expression on the left side in mammals and chicks is a key event, and is due to the release of calcium on the left possibly involving an ion pump and the Notch pathway

  5. Influence of Salts on the Partitioning of 5-Hydroxymethylfurfural in Water/MIBK.

    Science.gov (United States)

    Mohammad, Sultan; Held, Christoph; Altuntepe, Emrah; Köse, Tülay; Sadowski, Gabriele

    2016-04-28

    This study investigates the influence of electrolytes on the performance of extracting 5-hydroxymethylfurfural (HMF) from aqueous media using methyl isobutyl ketone (MIBK). For that purpose, liquid-liquid phase equilibria (LLE) of quaternary systems containing HMF, water, MIBK and salts were measured at atmospheric pressure and 298.15 K. The salts under investigation were composed of one of the anions NO(3-), SO4(2-), Cl(-), or CH3COO(-) and of one of the alkali cations Li(+), Na(+), or K(+). On the basis of these LLE data, the partition coefficient of HMF between the aqueous and the MIBK phase KHMF was determined. It could be shown that KHMF significantly depends on the kind and concentration of the added salt. Weak electrolytes (e.g., sulfates, acetates) caused salting-out, whereas nitrates caused salting-in of HMF to the aqueous phase. Unexpectedly, LiCl caused salting-out at low LiCl concentrations and salting-in at LiCl concentrations higher than 3 mol/kgH2O. The model electrolyte perturbed-chain SAFT (ePC-SAFT) was used to predict the salt influence on the LLE in the quaternary systems water/MIBK/HMF/salt in good agreement with the experimental data. On the basis of ePC-SAFT, it could be concluded that the different salting-out/salting-in behavior of the various salts is mainly caused by their different tendency to form ion pairs in aqueous solutions.

  6. Scattering of light by charged colloidal particles in salt solutions

    NARCIS (Netherlands)

    Vrij, A.; Overbeek, J.Th.G.

    1962-01-01

    In the interpretation of light scattering by colloidal electrolytes in salt solutions the interaction between the colloidal particles and the low molecular weight ions has to be taken into account. When fluctuation theory is applied for the derivation of a light-scattering equation, nonelectroneutra

  7. Learning SaltStack

    CERN Document Server

    Myers, Colton

    2015-01-01

    If you are a system administrator who manages multiple servers, then you know how difficult it is to keep your infrastructure in line. If you've been searching for an easier way, this book is for you. No prior experience with SaltStack is required.

  8. Photoluminescence of urine salts

    Science.gov (United States)

    Bordun, O.; Drobchak, O.

    2008-02-01

    Photoexcitation and luminescence spectra of dried urine sample under laser excitation were studied. Luminescence spectra of urine are determined by luminescence of urea which is the main component of urine. The presence of pathological salts in urine leads to the long-wave shifting of maxima of luminescence and to the decreasing of luminescence intensity.

  9. What Are Bath Salts?

    Science.gov (United States)

    ... in Missouri. She won the 3rd place 2013 Addiction Science Award . Read More » 0 Comments Bath Salts: An Emerging Danger February 05, 2013 / Sara Bellum ... copy Listen Drug Facts ... Nicotine, & E-Cigarettes Brain and Addiction Drug Overdoses in Youth HIV/AIDS and Drug ...

  10. Di-jet asymmetric momentum transported by QGP fluid

    Energy Technology Data Exchange (ETDEWEB)

    Tachibana, Y., E-mail: tachibana@nt.phys.s.u-tokyo.ac.jp [Department of Physics, The University of Tokyo, Tokyo 113-0033 (Japan); Theoretical Research Division, Nishina Center, RIKEN, Wako 351-0198 (Japan); Department of Physics, Sophia University, Tokyo 102-8554 (Japan); Hirano, T., E-mail: hirano@sophia.ac.jp [Department of Physics, Sophia University, Tokyo 102-8554 (Japan)

    2014-12-15

    We study the collective flow of the QGP-fluid which transports the energy and momentum deposited from jets. Simulations of the propagation of jets together with expansion of the QGP-fluid are performed by solving relativistic hydrodynamic equations numerically in the fully (3+1)-dimensional space. Mach cones are induced by the energy–momentum deposition from jets and extended by the expansion of the QGP. As a result, low-p{sub T} particles are enhanced at large angles from the jet axis. This provedes an intimate link between the observables in di-jet asymmetric events in heavy-ion collisions and theoretical pictures of the medium excitation by jet-energy deposition.

  11. Asymmetric bilayer graphene nanoribbon MOSFETs for analog and digital electronics

    Science.gov (United States)

    Dinarvand, A.; Ahmadi, V.; Darvish, Gh.

    2016-05-01

    In this paper, a new structure was proposed for bilayer graphene nanoribbon field-effect transistor (BGNFET) mainly to enhance the electrical characteristics in analog and digital applications. The proposed device uses two metallic gates on the top and bottom of a bilayer graphene nanoribbon, which is surrounded by SiO2 and connected to heavily doped source/drain contacts. Electrical properties of the proposed device were explored using fully self-consistent solution of Poisson and Schrödinger equations based on the nonequilibrium Green's function (NEGF) formalism. Significant improvements in the electrical behavior was seen in the simulation results for gates asymmetrically biased. The comparison with graphene nanoribbon FET showed that the proposed structure benefited from higher intrinsic voltage gain and cut-off frequency and improved switching characteristics such as delay and Ion/Ioff ratio.

  12. Carpinteria Salt Marsh Habitat Polygons

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — We identified five common habitat types in Carpinteria Salt Marsh: channels, pans (flats), marsh, salt flat and upland. We then drew polygons around each habitat...

  13. Salt ingestion caves.

    Directory of Open Access Journals (Sweden)

    Lundquist Charles A.

    2006-01-01

    Full Text Available Large vertebrate herbivores, when they find a salt-bearing layer of rock, say in a cliff face, can produce sizable voids where, overgenerations, they have removed and consumed salty rock. The cavities formed by this natural animal process constitute a uniqueclass of caves that can be called salt ingestion caves. Several examples of such caves are described in various publications. Anexample in Mississippi U.S.A., Rock House Cave, was visited by the authors in 2000. It seems to have been formed by deer orbison. Perhaps the most spectacular example is Kitum Cave in Kenya. This cave has been excavated to a length over 100 metersby elephants. An ancient example is La Cueva del Milodon in Chile, which is reported to have been excavated by the now extinctmilodon, a giant ground sloth. Still other possible examples can be cited. This class of caves deserves a careful definition. First, thecavity in rock should meet the size and other conventions of the locally accepted definition of a cave. Of course this requirement differsin detail from country to country, particularly in the matter of size. The intent is to respect the local conventions. The characteristicthat human entry is possible is judged to be a crucial property of any recognized cave definition. Second, the cavity should besignificantly the result of vertebrate animal consumption of salt-bearing rock. The defining process is that rock removed to form thecave is carried away in the digestive track of an animal. While sodium salts are expected to be the norm, other salts for which thereis animal hunger are acceptable. Also some other speleogenesis process, such as solution, should not be excluded as long as it issecondary in formation of a cave in question.

  14. Asymmetric tandem organic solar cells

    Science.gov (United States)

    Howells, Thomas J.

    where it is used to predict the short-circuit current (Jsc) generation of the sub-cells, which is not accessible experimentally. Current-matching is then used to predict the Jsc of the complete tandem device. . As a support to the optical modelling, ellipsometry measurements of thin films of ClAlPc are presented. These films of known thickness are analysed to extract the complex refractive index for use in optical modelling calculations. A dependence of the complex refractive index on film thickness and substrate is also noted. Finally, the external quantum efficiency (EQE) technique is considered as applied to solar cells, and an additional method is proposed to characterise current balancing in asymmetric tandem cells under illumination. This technique is verified experimentally by two separate sets of data..

  15. Polymer Conformations in Ionic Microgels in the Presence of Salt: Theoretical and Mesoscale Simulation Results

    Directory of Open Access Journals (Sweden)

    Hideki Kobayashi

    2017-01-01

    Full Text Available We investigate the conformational properties of polymers in ionic microgels in the presence of salt ions by molecular dynamics simulations and analytical theory. A microgel particle consists of coarse-grained linear polymers, which are tetra-functionally crosslinked. Counterions and salt ions are taken into account explicitly, and charge-charge interactions are described by the Coulomb potential. By varying the charge interaction strength and salt concentration, we characterize the swelling of the polyelectrolytes and the charge distribution. In particular, we determine the amount of trapped mobile charges inside the microgel and the Debye screening length. Moreover, we analyze the polymer extension theoretically in terms of the tension blob model taking into account counterions and salt ions implicitly by the Debye–Hückel model. Our studies reveal a strong dependence of the amount of ions absorbed in the interior of the microgel on the electrostatic interaction strength, which is related to the degree of the gel swelling. This implies a dependence of the inverse Debye screening length κ on the ion concentration; we find a power-law increase of κ with the Coulomb interaction strength with the exponent 3 / 5 for a salt-free microgel and an exponent 1 / 2 for moderate salt concentrations. Additionally, the radial dependence of polymer conformations and ion distributions is addressed.

  16. Salt fluoridation and oral health

    OpenAIRE

    Thomas M. Marthaler

    2013-01-01

    The aim of this paper is to make known the potential of fluoridated salt in community oral health programs, particularly in South Eastern Europe. Since 1922, the addition of iodine to salt has been successful in Switzerland. Goiter is virtually extinct. By 1945, the cariesprotective effect of fluorides was well established. Based on the success of water fluoridation, a gynecologist started adding of fluoride to salt. The sale of fluoridated salt began in 1956 in the Swiss Canton of Zurich,...

  17. A study of salt effects on the complexation between beta-cyclodextrins and bile salts based on the Hofmeister series

    DEFF Research Database (Denmark)

    Holm, Rene; Schonbeck, Christian; Somprasirt, Pitchayanun;

    2014-01-01

    bound drug molecules. The influence of Hofmeister ions on the binding constants of complexes between CDs (β-CD and hydroxypropylated β-CD) and bile salts (glycocholate and glycochenodeoxycholate) were examined by isothermal titration calorimetry. The chaotropic anions tended to weaken these inclusion...

  18. Salt enrichment of municipal sewage: New prevention approaches in Israel

    Science.gov (United States)

    Weber, Baruch; Avnimelech, Yoram; Juanico, Marcelo

    1996-07-01

    Wastewater irrigation is an environmentally sound wastewater disposal practice, but sewage is more saline than the supplied fresh water and the salts are recycled together with the water. Salts have negative environmental effects on crops, soils, and groundwater. There are no inexpensive ways to remove the salts once they enter sewage, and the prevention of sewage salt enrichment is the most immediately available solution. The body of initiatives presently structured by the Ministry of the Environment of Israel are herein described, with the aim to contribute to the search for a long-term solution of salinity problems in arid countries. The new initiatives are based on: (1) search for new technologies to reduce salt consumption and discharge into sewage; (2) different technologies to cope with different situations; (3) raising the awareness of the public and industry on the environmental implications of salinity pollution; and (4) an elastic legal approach expressed through new state-of-the-art regulations. The main contributor to the salinity of sewage in Israel is the watersoftening process followed by the meat koshering process. Some of the adopted technical solutions are: the discharge of the brine into the sea, the substitution of sodium by potassium salts in the ion-exchangers, the construction of centralized systems for the supply of soft water in industrial areas, the precipitation of Ca and Mg in the effluents from ion-exchangers and recycling of the NaCI solution, a reduction of the discharge of salts by the meat koshering process, and new membrane technology for salt recovery.

  19. Control of apoptosis by asymmetric cell division.

    Directory of Open Access Journals (Sweden)

    Julia Hatzold

    2008-04-01

    Full Text Available Asymmetric cell division and apoptosis (programmed cell death are two fundamental processes that are important for the development and function of multicellular organisms. We have found that the processes of asymmetric cell division and apoptosis can be functionally linked. Specifically, we show that asymmetric cell division in the nematode Caenorhabditis elegans is mediated by a pathway involving three genes, dnj-11 MIDA1, ces-2 HLF, and ces-1 Snail, that directly control the enzymatic machinery responsible for apoptosis. Interestingly, the MIDA1-like protein GlsA of the alga Volvox carteri, as well as the Snail-related proteins Snail, Escargot, and Worniu of Drosophila melanogaster, have previously been implicated in asymmetric cell division. Therefore, C. elegans dnj-11 MIDA1, ces-2 HLF, and ces-1 Snail may be components of a pathway involved in asymmetric cell division that is conserved throughout the plant and animal kingdoms. Furthermore, based on our results, we propose that this pathway directly controls the apoptotic fate in C. elegans, and possibly other animals as well.

  20. Improvement of penning ion sources

    CERN Document Server

    Bizyukov, A A; Kashaba, A Y; Sereda, K N

    2000-01-01

    It is shown that the loss of a longitudinal symmetry of magnetic field distribution in respect to the centre of the Penning discharge system causes change of electrostatic potential distribution in the discharge gap leads to appearance of asymmetry of current magnitude to the cathodes of the Penning cell,change of magnitude of current density and energy distribution of the ion beam extracted in a longitudinal direction.The use of an inhomogeneous magnetic field which is longitudinally asymmetrical concerning electrodes of the system allows to increase current efficiency of Penning ion sources from 0,2 to 0,55.

  1. [Development of new methods in asymmetric reactions and their applications].

    Science.gov (United States)

    Node, Manabu

    2002-01-01

    Several novel methods using chiral reagents and biocatalysts for asymmetric reactions are described. Among those reactions, asymmetric reduction via a novel tandem Michael addition/Meerwein-Ponndorf-Verley reduction of acyclic alpha,beta-unsaturated ketones using a chiral mercapto alcohol, asymmetric synthesis of allene-1,3-dicarboxylate via crystallization induced asymmetric transformation, and improved asymmetric nitroolefination of lactones and lactames at alpha-carbon using new chiral reagents were developed. In the reactions using biocatalysts, asymmetric dealkoxycarbonylation of bicyclic beta-keto diesters having sigma-symmetry with lipase or esterase to give optically active beta-keto esters, the asymmetric reduction of bicyclic 1,3-diketones having sigma-symmetry with Baker's yeast to give optically active keto alcohols, and the asymmetric aldol reaction of glycine with threonine aldolase were also developed. The above mentioned products were effectively utilized as chiral building blocks for the asymmetric synthesis of natural products and drugs.

  2. Physicochemical basis for the inhibitory effects of organic and inorganic salts on the growth of Pectobacterium carotovorum subsp. carotovorum and Pectobacterium atrosepticum.

    Science.gov (United States)

    Yaganza, Elian-Simplice; Tweddell, Russell J; Arul, Joseph

    2009-03-01

    Twenty-one salts were tested for their effects on the growth of Pectobacterium carotovorum subsp. carotovorum and Pectobacterium atrosepticum. In liquid medium, 11 salts (0.2 M) exhibited strong inhibition of bacterial growth. The inhibitory action of salts relates to the water-ionizing capacity and the lipophilicity of their constituent ions.

  3. Physicochemical Basis for the Inhibitory Effects of Organic and Inorganic Salts on the Growth of Pectobacterium carotovorum subsp. carotovorum and Pectobacterium atrosepticum▿

    OpenAIRE

    Yaganza, Elian-Simplice; Tweddell, Russell J.; Arul, Joseph

    2008-01-01

    Twenty-one salts were tested for their effects on the growth of Pectobacterium carotovorum subsp. carotovorum and Pectobacterium atrosepticum. In liquid medium, 11 salts (0.2 M) exhibited strong inhibition of bacterial growth. The inhibitory action of salts relates to the water-ionizing capacity and the lipophilicity of their constituent ions.

  4. Dc SQUIDs with asymmetric shunt resistors

    Energy Technology Data Exchange (ETDEWEB)

    Rudolph, Matthias; Nagel, Joachim; Kemmler, Matthias; Koelle, Dieter; Kleiner, Reinhold [Physikalisches Institut - Experimentalphysik II and Center for Collective Quantum Phenomena in LISAplus, Universitaet Tuebingen (Germany); Meckbach, Johannes Maximilian; Ilin, Konstantin; Siegel, Michael [Institut fuer Mikro- und Nanoelektronische Systeme, Karlsruhe Institute of Technology, Karlsruhe (Germany)

    2013-07-01

    We have investigated asymmetrically shunted Nb/Al-AlO{sub x}/Nb dc SQUIDs. Simulations based on the coupled Langevin equations predict that the optimum energy resolution ε, and thus also the noise performance of such an asymmetric SQUID, can be 3-4 times better than that of its symmetric counterpart. While keeping the total resistance R identical to a comparable symmetric SQUID with R{sup -1} = R{sub 1}{sup -1} + R{sub 2}{sup -1}, we shunted only one of the two Josephson junctions with R = R{sub 1,2}/2. Both types of SQUIDs were characterized with respect to their transport and noise properties at temperature T = 4.2 K, and we compared the experimental results with numerical simulations. Experiments yielded ε ∼ 32 ℎ for an asymmetric SQUID with an inductance L = 22 pH, whereas a comparable symmetric device achieved ε = 110 ℎ.

  5. Atomic forces between noble gas atoms, alkali ions, and halogen ions for surface interactions

    Science.gov (United States)

    Wilson, J. W.; Outlaw, R. A.; Heinbockel, J. H.

    1988-01-01

    The components of the physical forces between noble gas atoms, alkali ions, and halogen ions are analyzed and a data base developed from analysis of the two-body potential data, the alkali-halide molecular data, and the noble gas crystal and salt crystal data. A satisfactory global fit to this molecular and crystal data is then reproduced by the model to within several percent. Surface potentials are evaluated for noble gas atoms on noble gas surfaces and salt crystal surfaces with surface tension neglected. Within this context, the noble gas surface potentials on noble gas and salt crystals are considered to be accurate to within several percent.

  6. Mixed salt crystallisation fouling

    CERN Document Server

    Helalizadeh, A

    2002-01-01

    The main purpose of this investigation was to study the mechanisms of mixed salt crystallisation fouling on heat transfer surfaces during convective heat transfer and sub-cooled flow boiling conditions. To-date no investigations on the effects of operating parameters on the deposition of mixtures of calcium sulphate and calcium carbonate, which are the most common constituents of scales formed on heat transfer surfaces, have been reported. As part of this research project, a substantial number of experiments were performed to determine the mechanisms controlling deposition. Fluid velocity, heat flux, surface and bulk temperatures, concentration of the solution, ionic strength, pressure and heat transfer surface material were varied systematically. After clarification of the effect of these parameters on the deposition process, the results of these experiments were used to develop a mechanistic model for prediction of fouling resistances, caused by crystallisation of mixed salts, under convective heat transfer...

  7. Frost formation with salt

    OpenAIRE

    Guadarrama-Cetina, J.; Mongruel, A; González-Viñas, W; Beysens, D. A.

    2015-01-01

    The formation of frost in presence of salt (NaCl) crystal is experimentally investigated on a hydrophobic surface. It presents several remarkable features due to the interplay of salty-water saturation pressure evolution, initially lower than the saturation pressure of ice and water, and the percolating propagation of ice dendrites from defects throughout the supercooled water droplet pattern. In particular, it is remarkable that nucleation of supercooled water and/or ice is prevented around ...

  8. Thermochemical Properties of Nicotine Salts

    Directory of Open Access Journals (Sweden)

    Riggs DM

    2014-12-01

    Full Text Available The thermal gravimetric analysis (TGA and differential scanning calorimetry (DSC results presented in this report clearly show that the thermal stability and the endothermic peak nicotine release temperatures are different for different nicotine salts and these temperatures appear to be linked to the general microstructural details of the salt itself. In addition, the peak nicotine release temperatures are highly dependent upon the sample size used. The heat of vaporization for neat (non-protonated nicotine is also sample-size dependent. The TGA data showed that the least stable of the salts tested at elevated temperatures was the liquid salt nicotine triacetate followed by the crystalline materials (e.g., nicotine gallate and finally, the amorphous salts (e.g., nicotine alginate. The DSC results revealed that the liquid and crystalline salts exhibit nicotine release endotherms that are strongly related to the sample weight being tested. The amorphous salts show nicotine endotherm peak temperatures that are nearly independent of the sample weight. The range of peak nicotine release temperatures varied depending upon the specific salts and the sample size from 83 oC to well over 200 oC. Based on these results, the evolution of nicotine from the nicotine salt should be expected to vary based on the composition of the salt, the details of its microstructure, and the amount of nicotine salt tested.

  9. Asymmetric gear rectifies random robot motion

    Science.gov (United States)

    Li, He; Zhang, H. P.

    2013-06-01

    We experimentally study the dynamics of centimetric robots and their interactions with rotary gears through inelastic collisions. Under the impacts of self-propelled robots, a gear with symmetric teeth diffuses with no preferred direction of motion. An asymmetric gear, however, rectifies random motion of nearby robots which, in return, exert a torque on the gear and drive it into unidirectional motion. Rectification efficiency increases with the degree of gear asymmetry. Our work demonstrates that asymmetric environments can be used to rectify and extract energy from random motion of macroscopic self-propelled particles.

  10. Homogeneous asymmetric catalysis in fragrance chemistry.

    Science.gov (United States)

    Ciappa, Alessandra; Bovo, Sara; Bertoldini, Matteo; Scrivanti, Alberto; Matteoli, Ugo

    2008-06-01

    Opposite enantiomers of a chiral fragrance may exhibit different olfactory activities making a synthesis in high enantiomeric purity commercially and scientifically interesting. Accordingly, the asymmetric synthesis of four chiral odorants, Fixolide, Phenoxanol, Citralis, and Citralis Nitrile, has been investigated with the aim to develop practically feasible processes. In the devised synthetic schemes, the key step that leads to the formation of the stereogenic center is the homogeneous asymmetric hydrogenation of a prochiral olefin. By an appropriate choice of the catalyst and the reaction conditions, Phenoxanol, Citralis, and Citralis Nitrile were obtained in high enantiomeric purity, and odor profiles of the single enantiomers were determined.

  11. Asymmetric catalysis with short-chain peptides.

    Science.gov (United States)

    Lewandowski, Bartosz; Wennemers, Helma

    2014-10-01

    Within this review article we describe recent developments in asymmetric catalysis with peptides. Numerous peptides have been established in the past two decades that catalyze a wide variety of transformations with high stereoselectivities and yields, as well as broad substrate scope. We highlight here catalytically active peptides, which have addressed challenges that had thus far remained elusive in asymmetric catalysis: enantioselective synthesis of atropoisomers and quaternary stereogenic centers, regioselective transformations of polyfunctional substrates, chemoselective transformations, catalysis in-flow and reactions in aqueous environments.

  12. Asymmetric acoustic transmission in multiple frequency bands

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Hong-xiang, E-mail: jsdxshx@ujs.edu.cn [Research Center of Fluid Machinery Engineering and Technology, Jiangsu University, Zhenjiang 212013 (China); Laboratory of Modern Acoustics, Institute of Acoustics, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093 (China); State Key Laboratory of Acoustics, Institute of Acoustics, Chinese Academy of Sciences, Beijing 100190 (China); Yuan, Shou-qi, E-mail: Shouqiy@ujs.edu.cn [Research Center of Fluid Machinery Engineering and Technology, Jiangsu University, Zhenjiang 212013 (China); Zhang, Shu-yi [Laboratory of Modern Acoustics, Institute of Acoustics, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093 (China)

    2015-11-23

    We report both experimentally and numerically that the multi-band device of the asymmetric acoustic transmission is realized by placing two periodic gratings with different periods on both sides of two brass plates immersed in water. The asymmetric acoustic transmission can exist in four frequency bands below 1500 kHz, which arises from the interaction between various diffractions from the two gratings and Lamb modes in the brass plates immersed in water. The results indicate that the device has the advantages of multiple band, broader bandwidth, and simpler structure. Our finding should have great potential applications in ultrasonic devices.

  13. Integrated asymmetric vertical coupler pressure sensors

    Science.gov (United States)

    Kiyat, Isa; Kocabas, Askin; Akcag, Imran; Aydinli, Atilla

    2004-08-01

    Design and analysis of a novel pressure sensor based on a silicon-on-insulator asymmetric integrated vertical coupler is presented. The coupler is composed of a single mode low index waveguide and a thin silicon slab. Wavelength selective optical modulation of asymmetric vertical coupler is examined in detail. Its potential for sensing applications is highlighted as an integrated optical pressure sensor which can be realized by standard silicon micro-fabrication. Sensitivity of transmission of such couplers on refractive index change of silicon slab ensures that they are good candidates for applications requiring high sensitivities.

  14. Asymmetric localization in disordered Landau bands

    Energy Technology Data Exchange (ETDEWEB)

    Nita, M [Institute of Physics and Technology of Materials, PO Box MG7, Bucharest-Magurele (Romania); Aldea, A [Institute of Physics and Technology of Materials, PO Box MG7, Bucharest-Magurele (Romania); Zittartz, J [Institute of Theoretical Physics, Cologne University, 50937 Cologne (Germany)

    2007-06-06

    We show that, due to band mixing, the eigenstate localization within the disordered Landau bands gets an asymmetric structure: the degree of localization increases in the lower part of the band and decreases in the upper one. The calculation is performed for a two-dimensional lattice with the Anderson disorder potential and we prove that this effect is related to the upper shift of the extended states within the band and is enhanced by the disorder strength. The asymmetric localization and the energy shift disappear when the interband coupling is switched off.

  15. Asymmetric multiscale behavior in PM2.5 time series: Based on asymmetric MS-DFA

    Science.gov (United States)

    Zhang, Chen; Ni, Zhiwei; Ni, Liping

    2016-11-01

    Particulate matter with an aerodynamic diameter of 2.5 mm or less (PM2.5) is one of the most serious air pollution, considered most harmful for people by World Health Organisation. In this paper, we utilized the asymmetric multiscale detrended fluctuation analysis (A-MSDFA) method to explore the existence of asymmetric correlation properties for PM2.5 daily average concentration in two USA cities (Fresno and Los Angeles) and two Chinese cities (Hong Kong and Shanghai), and to assess the properties of these asymmetric correlations. The results show the existences of asymmetric correlations, and the degree of asymmetric for two USA cities is stronger than that of two Chinese cities. Further, most of the local exponent β(n) are smaller than 0.5, which indicates the existence of anti-persistent long-range correlation for PM2.5 time series in four cities. In addition, we reanalyze the asymmetric correlation by the A-MSDFA method with secant rolling windows of different sizes, which can investigate dynamic changes in the multiscale correlation for PM2.5 time series with changing window size. Whatever window sizes, the correlations are asymmetric and display smaller asymmetries at small scales and larger asymmetries at large scales. Moreover, the asymmetries become increasingly weaker with the increase of window sizes.

  16. Novel Electrolytes for Lithium Ion Batteries

    Energy Technology Data Exchange (ETDEWEB)

    Lucht, Brett L. [Univ. of Rhode Island, Kingston, RI (United States). Dept. of Chemistry

    2014-12-12

    We have been investigating three primary areas related to lithium ion battery electrolytes. First, we have been investigating the thermal stability of novel electrolytes for lithium ion batteries, in particular borate based salts. Second, we have been investigating novel additives to improve the calendar life of lithium ion batteries. Third, we have been investigating the thermal decomposition reactions of electrolytes for lithium-oxygen batteries.

  17. Transcriptional Regulation of Arabidopsis in Response to Salt Stress

    Institute of Scientific and Technical Information of China (English)

    Zhulong Chan

    2012-01-01

    Salt stress is a major factor limiting agricultural productivity worldwide.Adaptations to salt stress include avoidance by reduced sodium uptake,sequestration of toxic sodium ions away from the cytoplasm,or production of compatible solutes or osmoprotectants to reduce molecular disruption.Approaches to engineer salt stress resistance have included regulation of ion transport through introduction of Na+/H+ antiporter; synthesis of compatible solutes; or the introduction of transcription factors regulating expression of stress-responsive genes.On the other hand,naturally occurring variation among wild-type populations of plants also can be used to understand plant adaptive responses to their environments.In this study,we compared phenotypic and transcriptomic effects of constitutive expression of genes intended to confer salt stress tolerance by three different mechanisms:a transcription factor,CBF3/DREB1a; a metabolic gene,M6PR,for mannitol biosynthesis; and the Na+/H+ antiporter,SOS1.In the absence of salt,M6PR and SOS1 lines performed comparably with wild type; CBF3 lines exhibited dwarfing as reported previously.All three transgenes conferred fitness advantage when subjected to 100 mmol/L NaCI in the growth chamber.CBF3 and M6PR affected transcription of numerous abiotic stress-related genes as measured by Affymetrix microarray analysis.M6PR additionally modified expression of biotic stress and oxidative stress genes.Transcriptional effects of SOS1 were smaller and primarily limited to redox-related genes.In addition,we compared natural variations in salt tolerance between Ler and Sha ecotypes based on their responses to salt treatments and the results indicated that Ler was salt-sensitive,but Sha,which obtained a truncated RAS1 protein,was salt-tolerant.Transcriptome analysis revealed that many genes involved in secondary metabolism,photosynthesis,and protein synthesis were mainly down-regulated by salinity effects,while transposable element genes,microRNA and

  18. Preparation and Characterization of Amino Acids-Based Trimethoprim Salts

    Directory of Open Access Journals (Sweden)

    Afzal R. Mohammed

    2012-02-01

    Full Text Available Trimethoprim (TMP is a dihydrofolate reductase (DHFR inhibitor which prevents the conversion of dihydrofolic acid into tetrahydrofolic acid, resulting in the depletion of the latter and leading to bacterial death. Oral bioavailability of TMP is hindered by both its low solubility and low permeability. This study aims to prepare novel salts of TMP using anionic amino acids; aspartic and glutamic acid as counter ions in order to improve solubility and dissolution. TMP salts were prepared by lyophilisation and characterized using FT-IR spectroscopy, proton nuclear magnetic resonance (1HNMR, Differential Scanning Calorimetry (DSC and Thermogravimetric analysis (TGA. Both the amino acids formed salts with TMP in a 1:1 molar ratio and showed a 280 fold improvement in solubility. Investigation of the microbiological activity of the prepared salts against TMP sensitive Escherichia coli showed that the new salts not only retained antibacterial activity but also exhibited higher zone of inhibition which was attributed to improved physicochemical characters such as higher solubility and dissolution. The results are an important finding that could potentially impact on faster onset of antibacterial activity and reduced therapeutic dose when administered to patients. Studies are underway investigating the effect of ion-pairing TMP with amino acids on the permeability profile of the drug.

  19. Effects of salts on physicochemical, microstructural and thermal properties of potato starch.

    Science.gov (United States)

    Zhou, Hongxian; Wang, Chenjie; Shi, Liu; Chang, Tong; Yang, Hong; Cui, Min

    2014-08-01

    The objective of this study was to determine the effects of salts on the physicochemical, microstructural and thermal properties of potato starch. The salting-out ions were able to decrease the solubility, swelling power, transparency and particle size of potato starch significantly (ppotato starch granules, observed by a light microscopy at 50°C and 70°C, was consistent with the above results. Differential scanning calorimetry (DSC) analysis demonstrated an increase in gelatinization temperature and enthalpy with the addition of salting-out ions, whereas there was a reverse trend for the addition of salting-in ions. The effects of anions on these properties of potato starch follow the order of SCN(-)>I(-)>NO3(-)>Br(-)>Cl(-)>SO4(2-)>F(-), while effects of the cations follow the order of Li(+)>Na(+)>K(+), matching to the order of the Hofmeister series.

  20. CO2 decomposition using electrochemical process in molten salts

    Science.gov (United States)

    Otake, Koya; Kinoshita, Hiroshi; Kikuchi, Tatsuya; Suzuki, Ryosuke O.

    2012-08-01

    The electrochemical decomposition of CO2 gas to carbon and oxygen gas in LiCl-Li2O and CaCl2-CaO molten salts was studied. This process consists of electrochemical reduction of Li2O and CaO, as well as the thermal reduction of CO2 gas by the respective metallic Li and Ca. Two kinds of ZrO2 solid electrolytes were tested as an oxygen ion conductor, and the electrolytes removed oxygen ions from the molten salts to the outside of the reactor. After electrolysis in both salts, the aggregations of nanometer-scale amorphous carbon and rod-like graphite crystals were observed by transmission electron microscopy. When 9.7 %CO2-Ar mixed gas was blown into LiCl-Li2O and CaCl2-CaO molten salts, the current efficiency was evaluated to be 89.7 % and 78.5 %, respectively, by the exhaust gas analysis and the supplied charge. When a solid electrolyte with higher ionic conductivity was used, the current and carbon production became larger. It was found that the rate determining step is the diffusion of oxygen ions into the ZrO2 solid electrolyte.

  1. Ion Pairing in Alkali Nitrate Electrolyte Solutions.

    Science.gov (United States)

    Xie, Wen Jun; Zhang, Zhen; Gao, Yi Qin

    2016-03-10

    In this study, we investigate the thermodynamics of alkali nitrate salt solutions, especially the formation of contact ion pairs between alkali cation and nitrate anion. The ion-pairing propensity shows an order of LiNO3 activity coefficients and suggest that the empirical "law of matching water affinity" is followed by these alkali nitrate salt solutions. The spatial patterns of contact ion pairs are different in the three salt solutions studied here: Li(+) forms the contact ion pair with only one oxygen of the nitrate while Na(+) and K(+) can also be shared by two oxygens of the nitrate. In reproducing the salt activity coefficient using Kirkwood-Buff theory, we find that it is essential to include electronic polarization for Li(+) which has a high charge density. The electronic continuum correction for nonpolarizable force field significantly improves the agreement between the calculated activity coefficients and their experimental values. This approach also improves the performance of the force field on salt solubility. From these two aspects, this study suggests that electronic continuum correction can be a promising approach to force-field development for ions with high charge densities.

  2. Asymmetric poly(ethylene glycol) star polymers with a cholic acid core and their aggregation properties.

    Science.gov (United States)

    Luo, Juntao; Giguère, Guillaume; Zhu, X X

    2009-04-13

    Poly(ethylene glycol) (PEG) arms are grafted onto a cholic acid core via anionic polymerization, yielding star-shaped polymers with a unique asymmetric structure with facial amphiphilicity. Well-defined cholic acid-PEG(4) stars (polydispersity index, ca. 1.05) with tunable molar masses (ca. 1000-13,000) were obtained and characterized by the use of size exclusion chromatography, MALDI-TOF mass spectrometry, NMR spectroscopy, and thermal analysis. The asymmetric star polymers were found to aggregate differently from cholic acid salt. The critical aggregation concentrations of the star polymers were determined by surface tension measurements, and spherical aggregates of the polymers with different PEG chain lengths were observed by transmission electron microscopy using the freeze-fracture etching technique. The elongated aggregates formed by the sodium salt of cholic acid were also observed. The hydrodynamic diameters of the aggregates were also measured using dynamic light scattering technique. The formation of aggregates makes them interesting systems as potential drug carriers.

  3. THz operation of asymmetric-nanochannel devices

    NARCIS (Netherlands)

    Balocco, C.; Halsall, M.; Vinh, N. Q.; Song, A. M.

    2008-01-01

    The THz spectrum lies between microwaves and the mid-infrared, a region that remains largely unexplored mainly due to the bottleneck issue of lacking compact, solid state, emitters and detectors. Here, we report on a novel asymmetric-nanochannel device, known as the self-switching device, which can

  4. Asymmetric conditional volatility in international stock markets

    Science.gov (United States)

    Ferreira, Nuno B.; Menezes, Rui; Mendes, Diana A.

    2007-08-01

    Recent studies show that a negative shock in stock prices will generate more volatility than a positive shock of similar magnitude. The aim of this paper is to appraise the hypothesis under which the conditional mean and the conditional variance of stock returns are asymmetric functions of past information. We compare the results for the Portuguese Stock Market Index PSI 20 with six other Stock Market Indices, namely the SP 500, FTSE 100, DAX 30, CAC 40, ASE 20, and IBEX 35. In order to assess asymmetric volatility we use autoregressive conditional heteroskedasticity specifications known as TARCH and EGARCH. We also test for asymmetry after controlling for the effect of macroeconomic factors on stock market returns using TAR and M-TAR specifications within a VAR framework. Our results show that the conditional variance is an asymmetric function of past innovations raising proportionately more during market declines, a phenomenon known as the leverage effect. However, when we control for the effect of changes in macroeconomic variables, we find no significant evidence of asymmetric behaviour of the stock market returns. There are some signs that the Portuguese Stock Market tends to show somewhat less market efficiency than other markets since the effect of the shocks appear to take a longer time to dissipate.

  5. Dynamic Conditional Correlations for Asymmetric Processes

    NARCIS (Netherlands)

    M. Asai (Manabu); M.J. McAleer (Michael)

    2010-01-01

    textabstractThe paper develops two Dynamic Conditional Correlation (DCC) models, namely the Wishart DCC (WDCC) model and the Matrix-Exponential Conditional Correlation (MECC) model. The paper applies the WDCC approach to the exponential GARCH (EGARCH) and GJR models to propose asymmetric DCC models.

  6. Weak chaos in the asymmetric heavy top

    CERN Document Server

    Barrientos, M; Ranada, A F

    1995-01-01

    We consider the dynamics of the slightly asymmetric heavy top, a non-integrable system obtained from the Lagrange top by breaking the symmetry of its inertia tensor. It shows signs of weak chaos, which we study numerically. We argue that it is a good example for introducing students to non-integrability and chaos. (author)

  7. Catalytic Asymmetric Synthesis of Phosphine Boronates.

    Science.gov (United States)

    Hornillos, Valentín; Vila, Carlos; Otten, Edwin; Feringa, Ben L

    2015-06-26

    The first catalytic enantioselective synthesis of ambiphilic phosphine boronate esters is presented. The asymmetric boration of α,β-unsaturated phosphine oxides catalyzed by a copper bisphosphine complex affords optically active organoboronate esters that bear a vicinal phosphine oxide group in good yields and high enantiomeric excess. The synthetic utility of the products is demonstrated through stereospecific transformations into multifunctional optically active compounds.

  8. Beam-beam issues in asymmetric colliders

    Energy Technology Data Exchange (ETDEWEB)

    Furman, M.A.

    1992-07-01

    We discuss generic beam-beam issues for proposed asymmetric e{sup +}- e{sup -} colliders. We illustrate the issues by choosing, as examples, the proposals by Cornell University (CESR-B), KEK, and SLAC/LBL/LLNL (PEP-II).

  9. Three dimensional force balance of asymmetric droplets

    Science.gov (United States)

    Kim, Yeseul; Lim, Su Jin; Cho, Kun; Weon, Byung Mook

    2016-11-01

    An equilibrium contact angle of a droplet is determined by a horizontal force balance among vapor, liquid, and solid, which is known as Young's law. Conventional wetting law is valid only for axis-symmetric droplets, whereas real droplets are often asymmetric. Here we show that three-dimensional geometry must be considered for a force balance for asymmetric droplets. By visualizing asymmetric droplets placed on a free-standing membrane in air with X-ray microscopy, we are able to identify that force balances in one side and in other side control pinning behaviors during evaporation of droplets. We find that X-ray microscopy is powerful for realizing the three-dimensional force balance, which would be essential in interpretation and manipulation of wetting, spreading, and drying dynamics for asymmetric droplets. This research was supported by Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education (NRF-2016R1D1A1B01007133).

  10. Nucleation Process in Asymmetric Nuclear Matter

    CERN Document Server

    Peres-Menezes, D

    1998-01-01

    An extended version of the non linear Walecka model, with rho mesons and eletromagnetic field is used to investigate the possibility of phase transitions in hot (warm) nuclear matter, giving rise to droplet formation. Surface properties of asymmetric nuclear matter as the droplet surface energy and its thickness are also examined.

  11. Integrated Optical Asymmetric Coupler Pressure Sensor

    Science.gov (United States)

    Kiyat, Isa; Kocabas, Coskun; Aydinli, Atilla

    2004-05-01

    Analysis of a novel pressure sensor based on a silicon-on-insulator (SOI) asymmetric vertical coupler is presented. The integrated optical component is a coupler composed of a single mode (SM) low index waveguide and a thin silicon slab. High sensitivities of about 0.14 rad.kPa-1 should be achieved.

  12. Asymmetric relationships between proteins shape genome evolution.

    NARCIS (Netherlands)

    Notebaart, R.A.; Kensche, P.R.; Huynen, M.A.; Dutilh, B.E.

    2009-01-01

    BACKGROUND: The relationships between proteins are often asymmetric: one protein (A) depends for its function on another protein (B), but the second protein does not depend on the first. In metabolic networks there are multiple pathways that converge into one central pathway. The enzymes in the conv

  13. Standards vs. labels with imperfect competition and asymmetric information

    DEFF Research Database (Denmark)

    Baltzer, Kenneth Thomas

    2012-01-01

    I demonstrate that providing information about product quality is not necessarily the best way to address asymmetric information problems when markets are imperfectly competitive. In a vertical differentiation model I show that a Minimum Quality Standard, which retains asymmetric information...

  14. Standards vs. labels with imperfect competition and asymmetric information

    DEFF Research Database (Denmark)

    Baltzer, Kenneth Thomas

    I demonstrate that providing information about product quality is not necessarily the best way to address asymmetric information problems when markets are imperfectly competitive. In a vertical dierentiation model I show that a Minimum Quality Standard, which retains asymmetric information...

  15. Transport-limited water splitting at ion-selective interfaces during concentration polarization

    OpenAIRE

    Nielsen, Christoffer Peder; Bruus, Henrik

    2013-01-01

    We present an analytical model of salt- and water-ion transport across an ion-selective interface based on an assumption of local equilibrium of the water-dissociation reaction. The model yields current-voltage characteristics and curves of water-ion current versus salt-ion current, which are in qualitative agreement with experimental results published in the literature. The analytical results are furthermore in agreement with direct numerical simulations. As part of the analysis, we find app...

  16. Charge Asymmetric Cosmic Rays as a probe of Flavor Violating Asymmetric Dark Matter

    DEFF Research Database (Denmark)

    Masina, Isabella; Sannino, Francesco

    2011-01-01

    The recently introduced cosmic sum rules combine the data from PAMELA and Fermi-LAT cosmic ray experiments in a way that permits to neatly investigate whether the experimentally observed lepton excesses violate charge symmetry. One can in a simple way determine universal properties of the unknown...... component of the cosmic rays. Here we attribute a potential charge asymmetry to the dark sector. In particular we provide models of asymmetric dark matter able to produce charge asymmetric cosmic rays. We consider spin zero, spin one and spin one-half decaying dark matter candidates. We show that lepton...... flavor violation and asymmetric dark matter are both required to have a charge asymmetry in the cosmic ray lepton excesses. Therefore, an experimental evidence of charge asymmetry in the cosmic ray lepton excesses implies that dark matter is asymmetric....

  17. Effects of Hofmeister salt series on gluten network formation: Part I. Cation series.

    Science.gov (United States)

    Tuhumury, H C D; Small, D M; Day, L

    2016-12-01

    Different cationic salts were used to investigate the effects of the Hofmeister salt series on gluten network formation. The effects of cationic salts on wheat flour dough mixing properties, the rheological and the chemical properties of the gluten extracted from the dough with different respective salts, were investigated. The specific influence of different cationic salts on the gluten structure formation during dough mixing, compared to the sodium ion, were determined. The effects of different cations on dough and gluten of different flours mostly followed the Hofmeister series (NH4(+), K(+), Na(+), Mg(2+) and Ca(2+)). The impacts of cations on gluten structure and dough rheology at levels tested were relatively small. Therefore, the replacement of sodium from a technological standpoint is possible, particularly by monovalent cations such as NH4(+), or K(+). However the levels of replacement need to take into account sensory attributes of the cationic salts.

  18. Rheology of rock salt for salt tectonics modeling

    Directory of Open Access Journals (Sweden)

    Shi-Yuan Li

    2016-10-01

    Full Text Available Abstract Numerical modeling of salt tectonics is a rapidly evolving field; however, the constitutive equations to model long-term rock salt rheology in nature still remain controversial. Firstly, we built a database about the strain rate versus the differential stress through collecting the data from salt creep experiments at a range of temperatures (20–200 °C in laboratories. The aim is to collect data about salt deformation in nature, and the flow properties can be extracted from the data in laboratory experiments. Moreover, as an important preparation for salt tectonics modeling, a numerical model based on creep experiments of rock salt was developed in order to verify the specific model using the Abaqus package. Finally, under the condition of low differential stresses, the deformation mechanism would be extrapolated and discussed according to microstructure research. Since the studies of salt deformation in nature are the reliable extrapolation of laboratory data, we simplified the rock salt rheology to dislocation creep corresponding to power law creep (n = 5 with the appropriate material parameters in the salt tectonic modeling.

  19. Two dialkylammonium salts of 2-amino-4-nitrobenzoic acid: crystal structures and Hirshfeld surface analysis

    Directory of Open Access Journals (Sweden)

    James L. Wardell

    2016-12-01

    Full Text Available The crystal structures of two ammonium salts of 2-amino-4-nitrobenzoic acid are described, namely dimethylazanium 2-amino-4-nitrobenzoate, C2H8N+·C7H5N2O4−, (I, and dibutylazanium 2-amino-4-nitrobenzoate, C8H20N+·C7H5N2O4−, (II. The asymmetric unit of (I comprises a single cation and a single anion. In the anion, small twists are noted for the carboxylate and nitro groups from the ring to which they are connected, as indicated by the dihedral angles of 11.45 (13 and 3.71 (15°, respectively; the dihedral angle between the substituents is 7.9 (2°. The asymmetric unit of (II comprises two independent pairs of cations and anions. In the cations, different conformations are noted in the side chains in that three chains have an all-trans [(+-antiperiplanar] conformation, while one has a distinctive kink resulting in a (+-synclinal conformation. The anions, again, exhibit twists with the dihedral angles between the carboxylate and nitro groups and the ring being 12.73 (6 and 4.30 (10°, respectively, for the first anion and 8.1 (4 and 12.6 (3°, respectively, for the second. The difference between anions in (I and (II is that in the anions of (II, the terminal groups are conrotatory, forming dihedral angles of 17.02 (8 and 19.0 (5°, respectively. In each independent anion of (I and (II, an intramolecular amino-N—H...O(carboxylate hydrogen bond is formed. In the crystal of (I, anions are linked into a jagged supramolecular chain by charge-assisted amine-N—H...O(carboxylate hydrogen bonds and these are connected into layers via charge-assisted ammonium-N—H...O(carboxylate hydrogen bonds. The resulting layers stack along the a axis, being connected by nitro-N—O...π(arene and methyl-C—H...O(nitro interactions. In the crystal of (II, the anions are connected into four-ion aggregates by charge-assisted amino-N—H...O(carboxylate hydrogen bonding. The formation of ammonium-N—H...O(carboxylate hydrogen bonds, involving

  20. Salt fluoridation and oral health

    Directory of Open Access Journals (Sweden)

    Thomas M. Marthaler

    2013-11-01

    Full Text Available The aim of this paper is to make known the potential of fluoridated salt in community oral health programs, particularly in South Eastern Europe. Since 1922, the addition of iodine to salt has been successful in Switzerland. Goiter is virtually extinct. By 1945, the cariesprotective effect of fluorides was well established. Based on the success of water fluoridation, a gynecologist started adding of fluoride to salt. The sale of fluoridated salt began in 1956 in the Swiss Canton of Zurich, and several other cantons followed suit. Studies initiated in the early seventies showed that fluoride, when added to salt, inhibits dental caries. The addition of fluoride to salt for human consumption was officially authorized in 1980-82. In Switzerland 85% of domestic salt consumed is fluoridated and 67% in Germany. Salt fluoridation schemes are reaching more than one hundred million in Mexico, Colombia, Peru and Cuba. The cost of salt fluoridation is very low, within 0.02 and 0.05 € per year and capita. Children and adults of the low socio-economic strata tend to have substantially more untreated caries than higher strata. Salt fluoridation is by far the cheapest method for improving oral health. Conclusions. Salt fluoridation has cariostatic potential like water fluoridation (caries reductions up to 50%. In Europe, meaningful percentages of users have been attained only in Germany (67% and Switzerland (85%. In Latin America, there are more than 100 million users, and several countries have arrived at coverage of 90 to 99%. Salt fluoridation is by far the cheapest method of caries prevention, and billions of people throughout the world could benefit from this method.

  1. Ion permeable microcapsules for the release of biologically available ions for remineralization.

    Science.gov (United States)

    Davidson, Michael T; Greving, Theresa A; McHale, William A; Latta, Mark A; Gross, Stephen M

    2012-03-01

    The objective of this study was to investigate the effect of chemical structure, ion concentration, and ion type on the release rate of biologically available ions useful for remineralization from microcapsules with ion permeable membranes. A heterogeneous polymerization technique was utilized to prepare microcapsules containing either an aqueous solution of K₂HPO₄, Ca(NO₃)₂, or NaF. Six different polyurethane-based microcapsule shells were prepared and characterized based on ethylene glycol, butanediol, hexanediol, octanediol, triethylene glycol, and bisphenol A structural units. Ion release profiles were measured as a function of initial ion concentration within the microcapsule, ion type, and microcapsule chemical structure. The rate of ion release increased with initial concentration of ion stored in the microcapsule over a range of 0.5-3.0M. The monomer used in the synthesis of the membrane had a significant effect on ion release rates at 3.0 M salt concentration. At 1.0 M, the ethylene glycol released ions significantly faster than the hexanediol-, octanediol-, and butanediol-based microcapsules. Ion release was fastest for fluoride and slowest for phosphate for the salts used in this study. It was concluded that the microcapsules are capable of releasing calcium, phosphate, and fluoride ions in their biologically available form.

  2. Salt-gland secretion and blood flow in the goose.

    Science.gov (United States)

    Hanwell, A; Linzell, J L; Peaker, M

    1971-03-01

    1. Salt-gland blood flow in the domestic goose has been measured using a combination of Sapirstein's indicator fractionation technique for organ blood flow and Fegler's thermodilution method for cardiac output.2. Nasal salt secretion was induced by giving 0.5 M-NaCl or 0.154 M-NaCl I.V. or by giving artificial sea water by stomach tube into the proventriculus.3. During secretion, salt-gland blood flow increased from 82.7 +/- 21.9 ml./100 g tissue. min to as high as 2179 ml./100 g. min (mean 1209 +/- 140).4. The rate of secretion in response to salt loading was very variable and was not correlated with the rate of blood flow.5. From the data obtained, it could be calculated that the median values for the percentage extraction of ions from the arterial plasma were Na 15%, K 35%, Cl 21% and water 5.8%.6. Atropine abolished secretion but not the increase in blood flow produced by salt loading.7. Unilateral complete denervation abolished secretion from and the increase in blood flow through the operated but not the control gland.8. Anaesthesia, induced by pentobarbitone sodium, almost completely blocked secretion and the increase in blood flow in the salt-gland in response to salt loading.9. In geese given 0.5 or 0.154 M-NaCl I.V. a positive, significant correlation was found between the total amount of nasal secretion collected over 30 min and the concentrations of Na and Cl in the nasal fluid. However, when the time course of secretion was followed in any one bird, the rate of secretion was inversely related to the concentrations of Na and Cl.10. Harderian gland blood flow was not affected by salt loading.

  3. Ion-Ion Neutralization.

    Science.gov (United States)

    1980-12-31

    plasma were identified using a downstream quadrupole mass spectrometer. In these experimento it is a simple matter to establish H+(H 2 0):f as the...pressure as predicted by the Thomson t2rnary mechanism whicK hzr been suownr to be valid experimentally at hiTh rrsurs (,han and Peron, 1:EI4 hereafter t...of NO , NO2 ions in various gases and the ternary recombination coefficients of these ions in the higher pres:;ure ( Thomson ) re"ie. Equation (5) cr>n

  4. Toxicity of major geochemical ions to freshwater species

    Science.gov (United States)

    Extensive testing regarding the toxicity of major geochemical ions to Ceriodaphnia dubia, Hyalella azteca, and Pimephales promelas will be presented. For C. dubia, tests of single salts and binary mixtures in various dilution waters demonstrated multiple mechanisms of toxicity an...

  5. Salts affect the interaction of ZnO or CuO nanoparticles with wheat.

    Science.gov (United States)

    Stewart, Jacob; Hansen, Trevor; McLean, Joan E; McManus, Paul; Das, Siddhartha; Britt, David W; Anderson, Anne J; Dimkpa, Christian O

    2015-09-01

    Exposure to nanoparticles (NPs) that release metals with potential phytotoxicity could pose problems in agriculture. The authors of the present study used growth in a model growth matrix, sand, to examine the influence of 5 mmol/kg of Na, K, or Ca (added as Cl salts) and root exudates on transformation and changes to the bioactivity of copper(II) oxide (CuO) and zinc oxide (ZnO) NPs on wheat. These salt levels are found in saline agricultural soils. After 14 d of seedling growth, particles with crystallinity typical of CuO or ZnO remained in the aqueous fraction from the sand; particles had negative surface charges that differed with NP type and salt, but salt did not alter particle agglomeration. Reduction in shoot and root elongation and lateral root induction by ZnO NPs were mitigated by all salts. However, whereas Na and K promoted Zn loading into shoots, Ca reduced loading, suggesting that competition with Zn ions for uptake occurred. With CuO NPs, plant growth and loading was modified equally by all salts, consistent with major interaction with the plant with CuO rather than Cu ions. Thus, for both NPs, loading into plant tissues was not solely dependent on ion solubility. These findings indicated that salts in agricultural soils could modify the phytotoxicity of NPs.

  6. 硅改善盐胁迫下库拉索芦荟生长和离子吸收与分布%Silicate Improves Growth and Ion Absorption and Distribution in Aloe vera under Salt Stress

    Institute of Scientific and Technical Information of China (English)

    徐呈祥; 刘友良; 郑青松; 刘兆普

    2006-01-01

    Si 2.0 mmol/L处理明显缓解NaCl 100、200mmol/L胁迫120 d对库拉索芦荟(Aloe vera)生长的抑制作用.Si可显著降低NaCl胁迫下芦荟植株中的Na+和Cl-含量,提高K+含量,从而显著降低K+/Na+,促进根对K+的选择性吸收(ASK,Na)和K+向地上部的选择性运输(TSK,Na),以维持植株体内的离子稳态.根系和叶片横切面的X-射线能谱微区分析结果进一步证实了这一结果.Si改善盐胁迫下芦荟对K+的选择性吸收和运输的机制之一是通过显著提高盐胁迫下芦荟根细胞质膜H+-ATPase、液泡膜H+-ATPase和液泡膜H+-PPase的活性.%Si 2.0 mmol/L in irrigation solution alleviated significantly the inhibition of NaCl stress of 100 or 200mmol/L to aloe growth. Exogenously applied Si decreased significantly Na+ and Cl- contents, increased K+content and K+/Na+ ratio and selectivity ratio of absorption (ASK, Na) and of translocation (TSK, Na) to K+ and Na+in aloe plant under both NaCl 100 and 200 mmol/L stresses for 30 d. In this way, the ion homeostasis in aloe plant under NaCl stress was maintained, as was proved by X-ray microanalysis of root tip and leaf across sections.One of the mechanisms to achieve this may be the significant enhancement of H+-ATPase activities by the addition of silicate in plasma membrane and tonoplast, H+-pyrophosphatase (H+-PPase) activity in tonoplast isolated from aloe root tips under NaCl stress.

  7. Asymmetric Electrodes Constructed with PAN-Based Activated Carbon Fiber in Capacitive Deionization

    Directory of Open Access Journals (Sweden)

    Mingzhe Li

    2014-01-01

    Full Text Available Capacitive deionization (CDI method has drawn much attention for its low energy consumption, low pollution, and convenient manipulation. Activated carbon fibers (ACFs possess high adsorption ability and can be used as CDI electrode material. Herein, two kinds of PAN-based ACFs with different specific surface area (SSA were used for the CDI electrodes. The CDI performance was investigated; especially asymmetric electrodes’ effect was evaluated. The results demonstrated that PAN-based ACFs showed a high electrosorption rate (complete electrosorption in less than half an hour and moderate electrosorption capacity (up to 0.2 mmol/g. CDI experiments with asymmetric electrodes displayed a variation in electrosorption capacity between forward voltage and reverse voltage. It can be attributed to the electrical double layer (EDL overlap effect and inner pore potential; thus the ions with smaller hydrated ionic radius can be adsorbed more easily.

  8. Sodium: How to Tame Your Salt Habit

    Science.gov (United States)

    ... same amount of sodium as table salt. Use salt substitutes wisely. Some salt substitutes or light salts contain a mixture of table ... substitute — and get too much sodium. Also, many salt substitutes contain potassium chloride. Although potassium can lessen some ...

  9. POLYMERIZATION MECHANISM OF N-VINYLCARBAZOLE WITH CHIRALLY ORGANIC SALT AS CATALYST

    Institute of Scientific and Technical Information of China (English)

    1998-01-01

    The polymerization mechanism is described by the conductance change with the time during the polymerization. The mechanism can be explained by the equilibrium feature (i.e. main ion-pairs) between the free ions and the ion-pairs dissociated by the organic salt (-) Sp*+ (+) CSA*- (An asterisk represents the chirality) and the scheme of the polymerization process isdescribed mainly by the charge transfer complexes having chiral induction power.

  10. 咸水结冰灌溉对盐化潮土盐基离子剖面迁移规律的影响%Effects of Agricultural Irrigation by Melting Saline Water Ice on Soil Salt and Ion Movement Under Fluvo-Aquic Soils

    Institute of Scientific and Technical Information of China (English)

    车升国; 林治安; 赵秉强; 左余宝; 夏雪

    2011-01-01

    利用土柱模拟试验,设置淡水、咸水灌溉、咸水结冰和咸水结冰覆盖4个灌溉方式,研究咸水结冰灌溉条件下盐分运移及盐基离子Cl^-、SO4^2-、HCO^3-、Na^+、Mg^2+、K^+和Ca^2+的土层剖面迁移规律。结果表明:咸水直接浇灌使各土层土壤盐度提高,且盐分具有明显表层聚集特性,而咸水结冰后灌溉则显著降低表层0-40 cm土层的盐分盐度,配合秸秆覆盖措施则使表层的脱盐率进一步提高,特别是0-10 cm土层,土壤盐度仅为0.15 dS/m,与淡水处理尚未达显著性差异(P〉0.05)。咸水结冰灌溉显著改变盐基离子Cl^-、SO4^2-、HCO^3-、Na^+、Mg^2+、K^+和Ca^2+的土壤剖面分布特征,但不同离子的响应方式和影响程度存在差异。咸水结冰灌溉显著(P〈0.05)降低表层危害性较高的Na^+、SO4^2-和Cl^-浓度,而对危害性较小的Mg2+、K+和Ca2+则影响较小。咸水结冰灌溉可促进表层土壤的脱盐作用,淋洗主要危害性离子Na^+、Cl^-等,保持土壤根系分布密集层较低盐分水平和盐基离子平衡,缓解或消除盐分和盐基离子对作物生长的危害,配合秸秆覆盖则效果更加明显。%The control treatment(irrigation with fresh water,CK),irrigation with saline water(SW),irrigation with saline water ice(MI),and irrigation with saline water ice and wheat straw mulch(MI+SW) was conducted to study the mechanism of soil water,salt and ion movement using soil column modeling experiment based on the melting process.The results showed that compared to irrigation with fresh water,soil salinity was more under the saline water treatment with the salt aggregation in the surface.However,irrigation with saline water ice the salt content in 0-40 cm decreased significantly,with the value of 0.28 dS/m,while making wheat straw mulching the salt rejection rate improved,especially in the 0-10 cm depth,where the salinity was only 0.15 d

  11. Sample Results From Routine Salt Batch 7 Samples

    Energy Technology Data Exchange (ETDEWEB)

    Peters, T. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

    2016-01-14

    Strip Effluent Hold Tank (SEHT) and Decontaminated Salt Solution Hold Tank (DSSHT) samples from several of the “microbatches” of Integrated Salt Disposition Project (ISDP) Salt Batch (“Macrobatch”) 7B have been analyzed for 238Pu, 90Sr, 137Cs, cations (Inductively Coupled Plasma Emission Spectroscopy - ICPES), and anions (Ion Chromatography Anions - IC-A). The analytical results from the current microbatch samples are similar to those from previous macrobatch samples. The Actinide Removal Process (ARP) and the Modular Caustic-Side Solvent Extraction Unit (MCU) continue to show more than adequate Pu and Sr removal, and there is a distinct positive trend in Cs removal (increasing cesium decontamination), due to the use of the Next Generation Solvent (NGS). The bulk chemistry of the DSSHT and SEHT samples do not show any signs of unusual behavior.

  12. SWELLING EQUILIBRIUM OF NONIONIC POLYACRYLAMIDE HYDROGEL IN AQUEOUS SALT SOLUTIONS

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    A series of nonionic polyacrylamide hydrogels, using acrylamide as monomer and N,N’-methylene diacrylamide as crosslinking agent, were prepared by the free radical polymerization in aqueous solution. Swelling equilibria for the gels were carried out in aqueous solutions of NaCl, KCl, CaCl2, Na2HPO4 and K2HPO4 with concentration ranging from 10-3 to 5mol/kgH2O at 25℃. Experimental results revealed that the chlorides and phosphates cause a different behavior at higher salt concentration. The swelling ratio increases with increasing concentration of chlorides salts, while decreases with the increased phosphates salt concentration. The phenomena seem to be related to the different interactions of chloride and hydrogen phosphate ions with the network groups. Furthermore, the effects of different concentration of crosslinking agent and total monomers on gel swelling performance were also investigated.

  13. First-principles molecular dynamics modeling of the molten fluoride salt with Cr solute

    Energy Technology Data Exchange (ETDEWEB)

    Nam, H.O.; Bengtson, A.; Vörtler, K.; Saha, S.; Sakidja, R.; Morgan, D., E-mail: ddmorgan@wisc.edu

    2014-06-01

    Fluoride salts and their interactions with metals are of wide interest for the nuclear community. In this work, first-principles molecular dynamics (FPMD) was employed to study both pure molten fluoride salt and fluoride salt with dissolved solute Cr ions (a common corrosion product) at high temperature (823–1423 K). Two types of molten fluoride salts, namely flibe (LiF–BeF{sub 2}) and flinak (LiF–NaF–KF), with the Cr{sup 0}, Cr{sup 2+} and Cr{sup 3+} ions were chosen as a target system for the FPMD modeling. The prediction of thermo-kinetic properties of pure fluoride salt, such as the equilibrium volume, density, bulk modulus, coefficient of thermal expansion, and self-diffusion coefficient, provide useful extensions of existing data and verify the accuracy of the FPMD simulation in modeling of fluoride salts. The FPMD modeling of solute Cr in fluoride salt shows the effect of Cr valence on diffusivity and local structure in the salt.

  14. Enhancing molecule fluorescence with asymmetrical plasmonic antennas.

    Science.gov (United States)

    Lu, Guowei; Liu, Jie; Zhang, Tianyue; Shen, Hongming; Perriat, Pascal; Martini, Matteo; Tillement, Olivier; Gu, Ying; He, Yingbo; Wang, Yuwei; Gong, Qihuang

    2013-07-21

    We propose and justify by the finite-difference time-domain method an efficient strategy to enhance the spontaneous emission of a fluorophore with a multi-resonance plasmonic antenna. The custom-designed asymmetrical antenna consists of two plasmonic nanoparticles with different sizes and is able to couple efficiently to free space light through multiple localized surface plasmon resonances. This design simultaneously permits a large near-field excitation near the antenna as well as a high quantum efficiency, which results in an unusual and significant enhancement of the fluorescence of a single emitter. Such an asymmetrical antenna presents intrinsic advantages over single particle or dimer based antennas made using two identical nanostructures. This promising concept can be exploited in the large domain of light-matter interaction processes involving multiple frequencies.

  15. Design of Asymmetric Peptide Bilayer Membranes.

    Science.gov (United States)

    Li, Sha; Mehta, Anil K; Sidorov, Anton N; Orlando, Thomas M; Jiang, Zhigang; Anthony, Neil R; Lynn, David G

    2016-03-16

    Energetic insights emerging from the structural characterization of peptide cross-β assemblies have enabled the design and construction of robust asymmetric bilayer peptide membranes. Two peptides differing only in their N-terminal residue, phosphotyrosine vs lysine, coassemble as stacks of antiparallel β-sheets with precisely patterned charged lattices stabilizing the bilayer leaflet interface. Either homogeneous or mixed leaflet composition is possible, and both create nanotubes with dense negative external and positive internal solvent exposed surfaces. Cross-seeding peptide solutions with a preassembled peptide nanotube seed leads to domains of different leaflet architecture within single nanotubes. Architectural control over these cross-β assemblies, both across the bilayer membrane and along the nanotube length, provides access to highly ordered asymmetric membranes for the further construction of functional mesoscale assemblies.

  16. Asymmetric dark matter models in SO(10)

    Science.gov (United States)

    Nagata, Natsumi; Olive, Keith A.; Zheng, Jiaming

    2017-02-01

    We systematically study the possibilities for asymmetric dark matter in the context of non-supersymmetric SO(10) models of grand unification. Dark matter stability in SO(10) is guaranteed by a remnant Z2 symmetry which is preserved when the intermediate scale gauge subgroup of SO(10) is broken by a {126} dimensional representation. The asymmetry in the dark matter states is directly generated through the out-of-equilibrium decay of particles around the intermediate scale, or transferred from the baryon/lepton asymmetry generated in the Standard Model sector by leptogenesis. We systematically classify possible asymmetric dark matter candidates in terms of their quantum numbers, and derive the conditions for each case that the observed dark matter density is (mostly) explained by the asymmetry of dark matter particles.

  17. Asymmetric Dark Matter Models in SO(10)

    CERN Document Server

    Nagata, Natsumi; Zheng, Jiaming

    2016-01-01

    We systematically study the possibilities for asymmetric dark matter in the context of non-supersymmetric SO(10) models of grand unification. Dark matter stability in SO(10) is guaranteed by a remnant $\\mathbb{Z}_2$ symmetry which is preserved when the intermediate scale gauge subgroup of SO(10) is broken by a ${\\bf 126}$ dimensional representation. The asymmetry in the dark matter states is directly generated through the out-of-equilibrium decay of particles around the intermediate scale, or transferred from the baryon/lepton asymmetry generated in the Standard Model sector by leptogenesis. We systematically classify possible asymmetric dark matter candidates in terms of their quantum numbers, and derive the conditions for each case that the observed dark matter density is (mostly) explained by the asymmetry of dark matter particles.

  18. Cosmological signatures of time-asymmetric gravity

    CERN Document Server

    Cortês, Marina; Smolin, Lee

    2016-01-01

    We develop the model proposed by Cort\\^es, Gomes & Smolin, to predict cosmological signatures of time-asymmetric extensions of general relativity they proposed recently. Within this class of models the equation of motion of chiral fermions is modified by a torsion term. This term leads to a dispersion law for neutrinos that associates a new time-varying energy with each particle. We find a new neutrino contribution to the Friedmann equation resulting from the torsion term in the Ashtekar connection. In this note we explore the phenomenology of this term and observational consequences for cosmological evolution. We show that constraints on the critical energy density will ordinarily render this term unobservably small, a maximum of order $10^{-25}$ of the neutrino energy density today. However, if the time-asymmetric dark energy is tuned to cancel the cosmological constant, the torsion effect may be a dark matter candidate.

  19. Venture Capital Contracting Under Asymmetric Information

    OpenAIRE

    Jeffrey Trester

    1993-01-01

    The author develops a model of venture capital contracting in which the entrepreneur and venture capitalist contract under symmetric information. A condition of asymmetric information may arise subsequent to the first contract. The author shows that this condition makes debt contracts infeasible and leads to the use of preferred equity contracts. The author notes that discussions of the relation between venture capital and capital structure are rare. This paper expands the literature by addre...

  20. Fluorous Mixture Synthesis of Asymmetric Dendrimers

    Science.gov (United States)

    Jiang, Zhong-Xing; Yu, Yihua Bruce

    2010-01-01

    A divergent fluorous mixture synthesis (FMS) of asymmetric fluorinated dendrimers has been developed. Four generations of fluorinated dendrimers with the same fluorinated moiety were prepared with high efficiency, yield and purity. Comparison of the physicochemical properties of these dendrimers provided valuable information for their application and future optimization. This strategy has not only provided a practical method for the synthesis and purification of dendrimers, but also established the possibility of utilizing the same fluorinated moiety for FMS. PMID:20170088

  1. Asymmetric k-Center with Minimum Coverage

    DEFF Research Database (Denmark)

    Gørtz, Inge Li

    2008-01-01

    In this paper we give approximation algorithms and inapproximability results for various asymmetric k-center with minimum coverage problems. In the k-center with minimum coverage problem, each center is required to serve a minimum number of clients. These problems have been studied by Lim et al. [A....... Lim, B. Rodrigues, F. Wang, Z. Xu, k-center problems with minimum coverage, Theoret. Comput. Sci. 332 (1–3) (2005) 1–17] in the symmetric setting....

  2. New electric field in asymmetric magnetic reconnection.

    Science.gov (United States)

    Malakit, K; Shay, M A; Cassak, P A; Ruffolo, D

    2013-09-27

    We present a theory and numerical evidence for the existence of a previously unexplored in-plane electric field in collisionless asymmetric magnetic reconnection. This electric field, dubbed the "Larmor electric field," is associated with finite Larmor radius effects and is distinct from the known Hall electric field. Potentially, it could be an important indicator for the upcoming Magnetospheric Multiscale mission to locate reconnection sites as we expect it to appear on the magnetospheric side, pointing earthward, at the dayside magnetopause reconnection site.

  3. Asymmetric Information – Adverse Selection Problem

    Directory of Open Access Journals (Sweden)

    Dumitru MARIN

    2007-01-01

    Full Text Available The present paper makes an introduction in the contract theory starting with the definitions of asymmetric information and some of the problems that generate: moral hazard and adverse selection. We provide an insight of the latest empirical studies in adverse selection in different markets. An adverse selection model, based on Rothchild and Stiglitz is also present to give a perspective of the theoretical framework.

  4. Caenorhabditis elegans response to salt

    NARCIS (Netherlands)

    O.O. Umuerri (Oluwatoroti Omowayewa)

    2012-01-01

    textabstractThis thesis describes my work, where I used genetic methods to identify new genes involved in salt taste in C. elegans. In addition, I used calcium imaging to characterize the cellular response of C. elegans to salt. The thesis is divided into five sections and each section is summarized

  5. Asymmetric threat data mining and knowledge discovery

    Science.gov (United States)

    Gilmore, John F.; Pagels, Michael A.; Palk, Justin

    2001-03-01

    Asymmetric threats differ from the conventional force-on- force military encounters that the Defense Department has historically been trained to engage. Terrorism by its nature is now an operational activity that is neither easily detected or countered as its very existence depends on small covert attacks exploiting the element of surprise. But terrorism does have defined forms, motivations, tactics and organizational structure. Exploiting a terrorism taxonomy provides the opportunity to discover and assess knowledge of terrorist operations. This paper describes the Asymmetric Threat Terrorist Assessment, Countering, and Knowledge (ATTACK) system. ATTACK has been developed to (a) data mine open source intelligence (OSINT) information from web-based newspaper sources, video news web casts, and actual terrorist web sites, (b) evaluate this information against a terrorism taxonomy, (c) exploit country/region specific social, economic, political, and religious knowledge, and (d) discover and predict potential terrorist activities and association links. Details of the asymmetric threat structure and the ATTACK system architecture are presented with results of an actual terrorist data mining and knowledge discovery test case shown.

  6. Asymmetric Conditional Volatility in International Stock Markets

    CERN Document Server

    Ferreira, N B; Menezes, R; Ferreira, Nuno B.; Mendes, Diana A.; Menezes, Rui

    2006-01-01

    Recent studies show that a negative shock in stock prices will generate more volatility than a positive shock of similar magnitude. The aim of this paper is to appraise the hypothesis under which the conditional mean and the conditional variance of stock returns are asymmetric functions of past information. We compare the results for the Portuguese Stock Market Index PSI 20 with six other Stock Market Indices, namely the S&P 500, FTSE100, DAX 30, CAC 40, ASE 20, and IBEX 35. In order to assess asymmetric volatility we use autoregressive conditional heteroskedasticity specifications known as TARCH and EGARCH. We also test for asymmetry after controlling for the effect of macroeconomic factors on stock market returns using TAR and M-TAR specifications within a VAR framework. Our results show that the conditional variance is an asymmetric function of past innovations raising proportionately more during market declines, a phenomenon known as the leverage effect. However, when we control for the effect of chan...

  7. Multiple Traveling Salesmen in Asymmetric Metrics

    CERN Document Server

    Friggstad, Zachary

    2011-01-01

    We consider some generalizations of the Asymmetric Traveling Salesman Path problem. Suppose we have an asymmetric metric G = (V,A) with two distinguished nodes s,t. We are also given a positive integer k. The goal is to find k paths of minimum total cost from s to t whose union spans all nodes. We call this the k-Person Asymmetric Traveling Salesmen Path problem (k-ATSPP). Our main result for k-ATSPP is a bicriteria approximation that, for some parameter b >= 1 we may choose, finds between k and k + k/b paths of total length O(b log |V|) times the optimum value of an LP relaxation based on the Held-Karp relaxation for the Traveling Salesman problem. On one extreme this is an O(log |V|)-approximation that uses up to 2k paths and on the other it is an O(k log |V|)-approximation that uses exactly k paths. Next, we consider the case where we have k pairs of nodes (s_1,t_1), ..., (s_k,t_k). The goal is to find an s_i-t_i path for every pair such that each node of G lies on at least one of these paths. Simple appro...

  8. Traceless Synthesis of Asymmetrically Modified Bivalent Nucleosomes.

    Science.gov (United States)

    Lechner, Carolin C; Agashe, Ninad D; Fierz, Beat

    2016-02-18

    Nucleosomes carry extensive post-translational modifications (PTMs), which results in complex modification patterns that are involved in epigenetic signaling. Although two copies of each histone coexist in a nucleosome, they may not carry the same PTMs and are often differently modified (asymmetric). In bivalent domains, a chromatin signature prevalent in embryonic stem cells (ESCs), namely H3 methylated at lysine 4 (H3K4me3), coexists with H3K27me3 in asymmetric nucleosomes. We report a general, modular, and traceless method for producing asymmetrically modified nucleosomes. We further show that in bivalent nucleosomes, H3K4me3 inhibits the activity of the H3K27-specific lysine methyltransferase (KMT) polycomb repressive complex 2 (PRC2) solely on the same histone tail, whereas H3K27me3 stimulates PRC2 activity across tails, thereby partially overriding the H3K4me3-mediated repressive effect. To maintain bivalent domains in ESCs, PRC2 activity must thus be locally restricted or reversed.

  9. SPECT using asymmetric pinholes with truncated projections

    Energy Technology Data Exchange (ETDEWEB)

    Lin Jianyu; Meikle, Steven R, E-mail: jianyu.lin@curtin.edu.au [Ramaciotti Imaging Centre, Brain and Mind Research Institute, University of Sydney (Australia)

    2011-07-07

    Tomographic systems employing truncated projections have been developed for parallel and fan beam collimation and for cone beam CT but the idea has not been extensively explored in pinhole single photon emission computed tomography (SPECT). In this paper, we explore the sampling requirements and system performance of SPECT systems with asymmetric pinhole collimators and truncated projections. We demonstrate that complete 3D sampling can be achieved by using multiple detectors with truncated asymmetric pinholes, offset axially from each other, and a spiral orbit. The use of truncated projections can be exploited in the design of pinhole SPECT systems by moving the pinholes closer to the subject, resulting in increased sensitivity and improved spatial resolution. Truncated and untruncated pinhole systems were evaluated using the contrast-to-noise ratio (CNR) calculated from the linearized local impulse response as a figure of merit. The CNR for the truncated pinhole system was up to 60% greater than that for the untruncated system at matched resolution for a source voxel near the centre of a uniform phantom and 30% greater at the edge. We conclude that an object can be reconstructed from asymmetric pinholes with truncated projections, which leads to potentially important design considerations and applications in single- and multi-pinhole SPECT.

  10. Salt Lake in Chaidamu Basin

    Institute of Scientific and Technical Information of China (English)

    王良华

    2007-01-01

    Chaidamu Basin(柴达木盆地) is in the west of China. It covers an area(地区) of 220,000 square kilometres(平方公里). The number of salt lakes(盐湖) is more than twenty in it. Chaerhan(察尔汗) Salt Lake is the largest in this area. If you get here, you will find that in the lake there is no water but a thick layer(层) of salt. You can walk in it without difficulty, and cars can come and go across it. The thickest layer of salt in this basin is about fifty metres thick. People tried their best to use the salt to build house...

  11. Synthesis of Asymmetrical Organic Carbonates using CO2 as a Feedstock in AgCl/Ionic Liquid System at Ambient Conditions.

    Science.gov (United States)

    Hu, Jiayin; Ma, Jun; Lu, Lu; Qian, Qingli; Zhang, Zhaofu; Xie, Chao; Han, Buxing

    2017-01-10

    Synthesis of asymmetrical organic carbonates from the renewable and inexpensive CO2 is of great importance but also challenging, especially at ambient conditions. Herein, we found that some metal salt/ionic liquid catalyst systems were highly active for the synthesis of asymmetrical organic carbonates from CO2 , propargylic alcohols, and primary alcohols. Especially, the AgCl/1-butyl-3-methylimidazolium acetate ([Bmim][OAc]) system was very efficient for the reactions of a wide range of substrates at room temperature and atmospheric pressure, and the yields of the asymmetrical organic carbonates could approach 100 %. The catalyst system could be reused at least five times without changing its catalytic performance, and could be easily recovered and reused. A detailed study indicated that AgCl and [Bmim][OAc] catalyzed the reactions cooperatively, resulting in unique catalytic performance.

  12. Proteomic Analysis of Tomato Seedlings Response to Salt Stress

    Institute of Scientific and Technical Information of China (English)

    Xue Zhao; Feng Han; Shihua Shen

    2012-01-01

    The two species (Solanum pimpinellifolium-PI and S.lycopersicum-MM) of tomato showed marked differences in their responses to NaCI stress.PI appeared to be more tolerant to salt than MM.Comparative two-dimensional electrophoresis revealed that 187 and 110 protein spots were differentially expressed in the roots of PI and MM,respectively,in response to salt stress.Out of these spots,a total of 96 and 61 proteins were identified by MALDI-TOF MS analysis.The proteins identified included many previously characterized stress-responsive proteins and others related to processes including scavenging for reactive species; metabolism of energy,signal transduction; protein synthesis,cell growth and differentiation et al.The role of some of the proteins involved in the antioxidant defense mechanism,ion transport and compartmentalization of ions,and cell signaling pathways were discussed.Collectively,this work suggest that PI has more efficient antioxidant and defense machinery than MM,and that this is important for adapting to salt stress and for withstanding the oxidative stress imposed by high salt levels.

  13. Molten Salt Promoting Effect in Double Salt CO2 Absorbents

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Keling; Li, Xiaohong S.; Chen, Haobo; Singh, Prabhakar; King, David L.

    2016-01-01

    The purpose of this paper is to elaborate on the concept of molten salts as catalysts for CO2 absorption by MgO, and extend these observations to the MgO-containing double salt oxides. We will show that the phenomena involved with CO2 absorption by MgO and MgO-based double salts are similar and general, but with some important differences. This paper focuses on the following key concepts: i) identification of conditions that favor or disfavor participation of isolated MgO during double salt absorption, and investigation of methods to increase the absorption capacity of double salt systems by including MgO participation; ii) examination of the relationship between CO2 uptake and melting point of the promoter salt, leading to the recognition of the role of pre-melting (surface melting) in these systems; and iii) extension of the reaction pathway model developed for the MgO-NaNO3 system to the double salt systems. This information advances our understanding of MgO-based CO2 absorption systems for application with pre-combustion gas streams.

  14. High energy density asymmetric pseudocapacitors fabricated by graphene/carbon nanotube/MnO2 plus carbon nanotubes nanocomposites electrode

    Science.gov (United States)

    Hung, Chung Jung; Lin, Pang; Tseng, Tseung Yuen

    2014-08-01

    Novel graphene/carbon nanotubes (CNTs)/manganese oxide (MnO2) nanocomposites plus CNTs (GMC + C) and graphene/CNTs hybrid (GC) thin-film electrodes are prepared by electrophoretic deposition (EPD). These nanocomposite electrodes exhibit high surface area and interconnected pore networks. The GMC + C nanocomposite electrode shows excellent specific capacitance of 964 F g-1 at 1 A g-1, rate capability with the residual capacitance of 529 F g-1 at 500 mV s-1, and fast Na+ diffusion with intercalation value of 6.34 × 10-7 cm2 s-1, and deintercalation value of 8.86 × 10-7 cm2 s-1. Such excellent pseudocapacitive performances are attributed to low ion/electron transport resistances and short ion/electron diffusion lengths. Furthermore, novel aqueous electrolyte-based asymmetric pseudocapacitor having 1.8 V cell voltage is successfully fabricated using GMC + C nanocomposite as a cathode and GC nanocomposite as an anode. The optimized asymmetric pseudocapacitor possesses superior performance with a maximum energy density of record high 304 Wh kg-1 and retaining 56.2% of its initial specific energy density at the power density up to 242 kW kg-1. In addition, the asymmetric cell configuration also shows excellent cycling stability with 89% specific capacitance maintained after 10,000 cycles. These results suggest that our designed asymmetric pseudocapacitors have a high potential for practical applications.

  15. Anabaena sp. DyP-type peroxidase is a tetramer consisting of two asymmetric dimers.

    Science.gov (United States)

    Yoshida, Toru; Ogola, Henry Joseph Oduor; Amano, Yoshimi; Hisabori, Toru; Ashida, Hiroyuki; Sawa, Yoshihiro; Tsuge, Hideaki; Sugano, Yasushi

    2016-01-01

    DyP-type peroxidases are a newly discovered family of heme peroxidases distributed from prokaryotes to eukaryotes. Recently, using a structure-based sequence alignment, we proposed the new classes, P, I and V, as substitutes for classes A, B, C, and D [Arch Biochem Biophys 2015;574:49-55]. Although many class V enzymes from eukaryotes have been characterized, only two from prokaryotes have been reported. Here, we show the crystal structure of one of these two enzymes, Anabaena sp. DyP-type peroxidase (AnaPX). AnaPX is tetramer formed from Cys224-Cys224 disulfide-linked dimers. The tetramer of wild-type AnaPX was stable at all salt concentrations tested. In contrast, the C224A mutant showed salt concentration-dependent oligomeric states: in 600 mM NaCl, it maintained a tetrameric structure, whereas in the absence of salt, it dissociated into monomers, leading to a reduction in thermostability. Although the tetramer exhibits non-crystallographic, 2-fold symmetry in the asymmetric unit, two subunits forming the Cys224-Cys224 disulfide-linked dimer are related by 165° rotation. This asymmetry creates an opening to cavities facing the inside of the tetramer, providing a pathway for hydrogen peroxide access. Finally, a phylogenetic analysis using structure-based sequence alignments showed that class V enzymes from prokaryotes, including AnaPX, are phylogenetically closely related to class V enzymes from eukaryotes.

  16. Iminium Salts by Meerwein Alkylation of Ehrlich’s Aldehyde

    Directory of Open Access Journals (Sweden)

    Gerhard Laus

    2013-03-01

    Full Text Available 4-(Dimethylaminobenzaldehyde is alkylated at the N atom by dialkyl sulfates, MeI, or Me3O BF4. In contrast, ethylation by Et3O BF4 occurs selectively at the O atom yielding a quinoid iminium ion. 4-(Diethylaminobenzaldehyde is alkylated only at O by either Et or Me oxonium reagent. The iminium salts are prone to hydrolysis giving the corresponding hydrotetrafluoroborates. Five crystal structures were determined.

  17. Study on the Ion Association in PVdF-based Gel Polymer Electrolyte

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Gel polymer electrolytes based on the poly (vinylidene fluoride) (PVdF) and the electrolyte of LiClO4 in propylene carbonate (PC) were prepared by the solution casting technique. The ionic conductivity of the gel electrolytes was concentration of lithium salt. Because of the strong coulombiq attractions, the dissolved salt ions might aggregate into ion pairs and multiple ion aggregates. The analysis of DSC and X-ray diffraction revealed that the ions association occurred at higher concentration of lithium salt.

  18. NOVEL SALTS OF GRAPHITE AND A BORON NITRIDE SALT

    Energy Technology Data Exchange (ETDEWEB)

    Bartlett, Neil; Biagioni, R.N.; McQuillan, B.W.; Robertson, A.S.; Thompson, A.C

    1977-12-01

    Graphite is oxidized by O{sub 2}{sup +} AsF{sub 6}{sup -} and by OsF{sub 6} to give first-stage graphite salts C{sub 8}{sup +} MF{sub 6}{sup -} and S{sub 2}O{sub 6}F{sub 2} oxidizes both graphite and boron nitride to yield the salts C{sub 12}{sup +} SO{sub 3}F{sup -} and (BN){sub 4}{sup +} SO{sub 3}F{sup -}, the latter being the first example of a first-stage boron nitride salt.

  19. Zinc oxide nanoring embedded lacey graphene nanoribbons in symmetric/asymmetric electrochemical capacitive energy storage

    Science.gov (United States)

    Sahu, Vikrant; Goel, Shubhra; Sharma, Raj Kishore; Singh, Gurmeet

    2015-12-01

    This article describes the synthesis and characterization of ZnO nanoring embedded graphene nanoribbons. Patterned holes (mesopore dia.) in graphene nanoribbons are chemically generated, leading to a high density of the edge planes. These planes carry negatively charged surface groups (like -COOH and -OH) and therefore anchor the metal ions in a cordial fashion forming a string of metal ions along the edge planes. These strings of imbibed metal ions precipitate as tiny ZnO nanorings over lacey graphene nanoribbons. The thus obtained graphene nanoribbon (GNR) based hierarchical ZnO mesoporous structures are three dimensionally accessible to the electrolyte and demonstrate high performance in capacitive energy storage. The ZnO/GNR nanocomposite electrode in an asymmetric supercapacitor device with lacey reduced graphene oxide nanoribbons (LRGONRs) as a negative electrode exhibits a 2.0 V potential window in the aqueous electrolyte and an ultra-short time constant (0.08 s). The wide potential window consequently increased the energy density from 6.8 Wh kg-1 (ZnO/GNR symmetric) to 9.4 Wh kg-1 (ZnO/GNR||LRGONR asymmetric). The relaxation time constant obtained for the asymmetric supercapacitor device was three orders of magnitude less compared to the ZnO (symmetric, 33 s) supercapacitor device. The high cycling stability of ZnO/GNR||LRGONR up to 96.7% capacitance retention, after 5000 GCD cycles at 2 mA cm-2, paves the way to a high performance aqueous electrochemical supercapacitive energy storage.This article describes the synthesis and characterization of ZnO nanoring embedded graphene nanoribbons. Patterned holes (mesopore dia.) in graphene nanoribbons are chemically generated, leading to a high density of the edge planes. These planes carry negatively charged surface groups (like -COOH and -OH) and therefore anchor the metal ions in a cordial fashion forming a string of metal ions along the edge planes. These strings of imbibed metal ions precipitate as tiny Zn

  20. Heterogeneous reaction of NO2 with sea salt particles

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    To understand how NO2 reacts with sea salt particles in the atmosphere of Mega-cities in coastal zones,the heterogeneous reaction of NO2 on the surface of wet sea salt was investigated with diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) and ion chromatography (IC).Kinetic measurements indicated that nitrate formation on sea salt was second order in NO 2 concentration and reactive uptake coefficients were (5.51 ± 0.19) × 10-7 and 1.26 × 10-6 respectively under 0% and 20% relative humidity (RH) at NO 2 molecular concentration of 1.96 × 1015 mol/cm3.The results showed that liquid water was formed at the site of MgCl2·6H2O,CaCl2·2H2O on the surface of sea salt and made the reaction more sustainable by releasing hydrated water and absorbing water from air even under a low RH (30%).Therefore,pure NaCl particles should not be used to represent sea salt in studies of the heterogeneous reaction with NO2.

  1. Differential Toxicities of Nickel Salts to the Nematode Caenorhabditis elegans.

    Science.gov (United States)

    Meyer, Dean; Birdsey, Jennifer M; Wendolowski, Mark A; Dobbin, Kevin K; Williams, Phillip L

    2016-08-01

    This study focused on assessing whether nickel (Ni) toxicity to the nematode Caenorhabditis elegans was affected by the molecular structure of the Ni salt used. Nematodes were exposed to seven Ni salts [Ni sulfate hexahydrate (NiSO4·6H2O), Ni chloride hexahydrate (NiCl2·6H2O), Ni acetate tetrahydrate (Ni(OCOCH3)2·4H2O), Ni nitrate hexahydrate (N2NiO6·6H2O), anhydrous Ni iodide (NiI2), Ni sulfamate hydrate (Ni(SO3NH2)2·H2O), and Ni fluoride tetrahydrate (NiF2·4H2O)] in an aquatic medium for 24 h, and lethality curves were generated and analyzed. Ni fluoride, Ni iodide, and Ni chloride were most toxic to C. elegans, followed by Ni nitrate, Ni sulfamate, Ni acetate, and Ni sulfate. The LC50 values of the halogen-containing salts were statistically different from the corresponding value of the least toxic salt, Ni sulfate. This finding is consistent with the expected high bioavailability of free Ni ions in halide solutions. We recommend that the halide salts be used in future Ni testing involving aquatic invertebrates.

  2. Novel compliant electrodes based on platinum salt reduction

    Science.gov (United States)

    Delille, Remi; Urdaneta, Mario; Hsieh, Kuangwen; Smela, Elisabeth

    2006-03-01

    A compliant electrode material is presented that was inspired by the electroding process used to manufacture ionic polymer-metal composites (IPMCs). However, instead of an ion-exchange membrane, a UV-curable acrylated urethane elastomer is employed. The electrode material consists of the UV-curable elastomer (Loctite 3108) loaded with tetraammineplatinum(II) chloride salt particles through physical mixing and homogenization. The composite material is made conductive by immersion in a reducing agent, sodium borohydride, which reduces the salt to platinum metal on the surface of the elastomer film. Because the noble metal is mixed into the elastomer precursor as a salt, the amount of UV light absorbed by the precursor is not significantly reduced, and the composite loses little photopatternability. As a result meso-scale electrodes of varying geometries can be formed by exposing the precursor/salt mixture through a mask. The materials are mechanically and electrically characterized. The percolation threshold of the composite is estimated to be 9 vol. % platinum salt, above which the compliant electrode material exhibits a maximum conductivity of 1 S/cm. The composite maintains its electrical conductivity under axial tensile strains of up to 40%.

  3. Soluble salt deposit in the Nihewan beds and its environmental significance

    Institute of Scientific and Technical Information of China (English)

    李容全; 乔建国; 邱维理; 翟秋敏; 李永良

    2000-01-01

    Observation and experimental analysis of soluble salt deposit along four profiles across the strata deposited in Nihewan paleolake basin enabled us to recognize the nature and evolution stages of the Nihewan paleolake and its significance in stratigraphical division and pa-leo-environmental reconstruction. The Nihewan paleolake was at least a weak-saline to semi-saline lake and represents an intracontinental lake in the semi-arid region. The lower member of sedimentary strata in the paleolake contains gypsum layer and gypsum lamellae. Soluble salt is mainly composed of SO42- and Ca2+ ions, representing a trend of the paleolake evolvinginto a stage of sulfate lake. The upper member of the strata has predominantly Cl-, K+, and Na+ ions in soluble salt, indicating a starting development of the paleolake to chlorite lake, but no salt rock was deposited, indicating a drying trend of the area.

  4. Ion Atmosphere Near Nucleic Acids

    Science.gov (United States)

    Mohanty, Udayan

    2015-03-01

    We will discuss all­atom structure based model that explicitly includes ionic effects, i.e., electrostatic interactions with explicit magnesium ions and implicit KCl that allow us to carry out explicit solvent molecular dynamics simulations of adenine riboswitch and SAM­I riboswitch. Our predictions for the excess ions around the riboswitch, and the magnesium­RNA interaction free energy will be compared with experimental data. We will provide upper and lower bounds for preferential interaction coefficient, a statistical mechanical quantity that is a measure of excess ion atmosphere around a polyelectrolyte. We will discuss the role of surface charge density of mobile ions from added salt in determining the counterion release entropy associated with chain collapse. Finally, the Poisson's ratio of oligomeric DNA will be determined. (Work done in collaboration with R. Hayes, J. Noel, P. Whitford, S. Hennelly, J. Onuchic, and K. Sanbonmatsu.) Work supported by fellowship from John Simon Guggenheim Memorial Foundation.

  5. Lipid reassembly in asymmetric Langmuir-Blodgett/Langmuir-Schaeffer bilayers.

    Science.gov (United States)

    Yuan, Jie; Hao, Changchun; Chen, Maohui; Berini, Pierre; Zou, Shan

    2013-01-08

    Molecular-reorganization-induced morphology alteration in asymmetric substrate-supported lipid bilayers (SLBs) was directly visualized by means of atomic force microscopy (AFM) and total internal reflection fluorescence (TIRF) microscopy. SLB samples were fabricated on mica-on-glass and glass substrates by Langmuir-Blodgett (LB)/Langmuir-Schaeffer (LS) using binary lipid mixtures, namely, 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC)/1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) and ternary mixtures DOPC/DPPC/1,2-dioleoyl-sn-glycero-3-phospho-L-serine (DOPS), labeled with 0.2 mol % Texas Red 1,2-dihexadecanoyl-sn-glycero-3-phosphoethanolamine triethylammonium salt (TR-DHPE) dye. Phase segregations were characterized by TIRF imaging, and DPPC-enriched domain structures were also observed. Interestingly for ∼40% (n = 6) of the samples with binary mixtures in the LB leaflet and a single component in the LS leaflet, that is, (DOPC/DPPC)(LB)+DOPC(LS), the contrast of the DPPC domains changed from the original dark (without dye) to bright (more TR dye partitioning) on TIRF images, returning to dark again. This contrast reverse was also correlated to AFM height images, where a DPPC-DPPC gel phase was spotted after the TIRF image contrast returned to dark. The rupture force mapping results measured on these binary mixture samples also confirmed unambiguously the formation of DPPC-DPPC gel domain components during the contrast change. The samples were tracked over 48 h to investigate the lipid molecule movements in both the DPPC domains and the DOPC fluid phase. The fluorescence contrast changes from bright to dark in SLBs indicate that the movement of dye molecules was independent of the movement of lipid molecules. In addition, correlated multimodal imaging using AFM, force mapping, and fluorescence provides a novel route to uncover the reorganization of lipid molecules at the solid-liquid interface, suggesting that the dynamics of dye molecules is highly

  6. Nitric oxide alleviates salt stress inhibited photosynthetic response by interacting with sulfur assimilation in mustard

    Directory of Open Access Journals (Sweden)

    Mehar eFatma

    2016-04-01

    Full Text Available The role of nitric oxide (NO and/or sulfur (S on stomatal and photosynthetic responses was studied in mustard (Brassica juncea L. in presence or absence of salt stress. The combined application of 100 µM NO (as sodium nitroprusside and 200 mg S kg-1 soil (excess-S more prominently influenced stomatal behaviour, photosynthetic and growth responses in the absence of salt stress and alleviated salt stress effects on photosynthesis. Plants receiving combined treatment of NO plus excess-S showed well-developed thylakoid membrane and properly stacked grana lamellae under salt stress, while the chloroplasts from salt-stressed plants had disorganized thylakoids. Moreover, the leaves from the NO and excess-S treated plants exhibited lower superoxide ion accumulation under salt stress, induced activity of ATP-sulfurylase (ATPS, catalase (CAT, ascorbate peroxidase (APX and glutathione reductase (GR and optimized NO generation that helped in minimizing oxidative stress. The enhanced S-assimilation of these plants resulted in increased production of cysteine (Cys and glutathione (GSH reduced. These findings indicated that NO influenced photosynthesis under salt stress by regulating oxidative stress and its effects on S-assimilation, an antioxidant system and NO generation.The results suggest that NO improves photosynthetic responses of plants grown under salt stress more effectively when plants received excess-S. Thus, excess-S conditions may be adopted for higher impact of NO in the reversal of salt stress effects on photosynthesis.

  7. Will salt repositories be dry?

    Science.gov (United States)

    Bredehoeft, John D.

    The National Academy of Science committee that considered geologic disposal of nuclear waste in the mid-1950s recommended salt as a repository medium, partly because of its high thermal conductivity and because it was believed to be “dry” (perhaps the appropriate thought is “impermeable”). Certainly, the fact that Paleozoic salt deposits exist in many parts of t h e world is evidence for very low rates of dissolution by moving groundwater. The fact that the dissolution rates were so small led many scientists to the conclusion that the salt beds were nearly impermeable. The major source of brine within the salt beds was thought to be fluid inclusions within salt crystals, which could migrate through differential solution toward a source of high heat. The idea that salt was uniformly “dry” was revised when exploratory drilling in the vicinity of the Waste Isolation Pilot Plant (WIPP) in New Mexico encountered brines within the Castile Formation, an evaporite deposit below the Salado Formation. The brine reservoirs were thought to be isolated pockets of brine in an otherwise “impermeable” salt section.

  8. Clinical and psychological characteristics of patients with arterial hypertension, consuming an increased amount of salt

    OpenAIRE

    O. B. Poselyugina

    2015-01-01

    Objective: to Study the potential development of links between the formation of neurotic disorders personality and high salt intake (S) with food in patients with arterial hypertension (AH).Materials and methods: the study involved 229 patients with essential hypertension. We determined the threshold of taste sensitivity to salt (TTS), the daily excretion of sodium ions in urine, was assessed psychological status of the patients, the type of attitude to the disease (LOBI), the severity of dep...

  9. Stable colloids in molten inorganic salts

    Science.gov (United States)

    Zhang, Hao; Dasbiswas, Kinjal; Ludwig, Nicholas B.; Han, Gang; Lee, Byeongdu; Vaikuntanathan, Suri; Talapin, Dmitri V.

    2017-02-01

    A colloidal solution is a homogeneous dispersion of particles or droplets of one phase (solute) in a second, typically liquid, phase (solvent). Colloids are ubiquitous in biological, chemical and technological processes, homogenizing highly dissimilar constituents. To stabilize a colloidal system against coalescence and aggregation, the surface of each solute particle is engineered to impose repulsive forces strong enough to overpower van der Waals attraction and keep the particles separated from each other. Electrostatic stabilization of charged solutes works well in solvents with high dielectric constants, such as water (dielectric constant of 80). In contrast, colloidal stabilization in solvents with low polarity, such as hexane (dielectric constant of about 2), can be achieved by decorating the surface of each particle of the solute with molecules (surfactants) containing flexible, brush-like chains. Here we report a class of colloidal systems in which solute particles (including metals, semiconductors and magnetic materials) form stable colloids in various molten inorganic salts. The stability of such colloids cannot be explained by traditional electrostatic and steric mechanisms. Screening of many solute–solvent combinations shows that colloidal stability can be traced to the strength of chemical bonding at the solute–solvent interface. Theoretical analysis and molecular dynamics modelling suggest that a layer of surface-bound solvent ions produces long-ranged charge-density oscillations in the molten salt around solute particles, preventing their aggregation. Colloids composed of inorganic particles in inorganic melts offer opportunities for introducing colloidal techniques to solid-state science and engineering applications.

  10. Hot pressed K+ ion conducting solid polymer electrolytes: synthesis, ion conduction and polymeric battery fabrication

    Science.gov (United States)

    Chandra, Angesh

    2016-07-01

    Synthesis and ion transport studies of hot pressed K+ ion conducting solid polymer electrolytes (SPEs): (1 - x) PEO: x KBr, where 0 polymer-salt complexation in SPE composition: (70:30) with conductivity ( σ) 5.01 × 10-7 S cm-1 from the room temperature conductivity measurements. Materials characterization and polymer-salt complexations of present SPEs have been explained with the help of various techniques viz. X-ray diffraction, Fourier transform infrared, differential scanning calorimetry, thermogravimetric analysis, scanning electron microscopy technique. To explain the ion conduction in the present SPEs, temperature dependent ionic conductivity ( σ), ionic mobility ( μ), mobile ion concentration ( n), ionic transference number ( t ion ) and ionic drift velocity ( v d ) have been calculated with the help of various experimental techniques. A solid state polymer battery is also fabricated by using the present SPE as an electrolyte and have been calculated their important cell parameters at room temperature.

  11. Postharvest application of organic and inorganic salts to control potato (Solanum tuberosum L.) storage soft rot: plant tissue-salt physicochemical interactions.

    Science.gov (United States)

    Yaganza, E S; Tweddell, R J; Arul, J

    2014-09-24

    Soft rot caused by Pectobacterium sp. is a devastating disease affecting stored potato tubers, and there is a lack of effective means of controlling this disease. In this study, 21 organic and inorganic salts were tested for their ability to control soft rot in potato tubers. In the preventive treatment, significant control of soft rot was observed with AlCl3 (≥66%) and Na2S2O3 (≥57%) and to a lesser extent with Al lactate and Na benzoate (≥34%) and K sorbate and Na propionate (≥27%). However, only a moderate control was achieved by curative treatment with AlCl3 and Na2S2O3 (42%) and sodium benzoate (≥33%). Overall, the in vitro inhibitory activity of salts was attenuated in the presence of plant tissue (in vivo) to different degrees. The inhibitory action of the salts in the preventive treatment, whether effective or otherwise, showed an inverse linear relationship with water ionization capacity (pK') of the salt ions, whereas in the curative treatment, only the effective salts showed this inverse linear relationship. Salt-plant tissue interactions appear to play a central role in the attenuated inhibitory activity of salts in potato tuber through reduction in the availability of the inhibitory ions for salt-bacteria interactions. This study demonstrates that AlCl3, Na2S2O3, and Na benzoate have potential in controlling potato tuber soft rot and provides a general basis for understanding of specific salt-tissue interactions.

  12. Thermodynamic characterization of salt components for Molten Salt Reactor fuel

    OpenAIRE

    Capelli, E.

    2016-01-01

    The Molten Salt Reactor (MSR) is a promising future nuclear fission reactor technology with excellent performance in terms of safety and reliability, sustainability, proliferation resistance and economics. For the design and safety assessment of this concept, it is extremely important to have a thorough knowledge of the physico-chemical properties of molten fluorides salts, which are one of the best options for the reactor fuel. This dissertation presents the thermodynamic description of the ...

  13. Deracemization of Axially Chiral Nicotinamides by Dynamic Salt Formation with Enantiopure Dibenzoyltartaric Acid (DBTA

    Directory of Open Access Journals (Sweden)

    Fumitoshi Yagishita

    2013-11-01

    Full Text Available Dynamic atroposelective resolution of chiral salts derived from oily racemic nicotinamides and enantiopure dibenzoyltartaric acid (DBTA was achieved by crystallization. The absolute structures of the axial chiral nicotinamides were determined by X-ray structural analysis. The chirality could be controlled by the selection of enantiopure DBTA as a chiral auxiliary. The axial chirality generated by dynamic salt formation was retained for a long period after dissolving the chiral salt in solution even after removal of the chiral acid. The rate of racemization of nicotinamides could be controlled based on the temperature and solvent properties, and that of the salts was prolonged compared to free nicotinamides, as the molecular structure of the pyridinium ion in the salts was different from that of acid-free nicotinamides.

  14. Organocatalytic Asymmetric 1,6-Addition/1,4-Addition Sequence to 2,4-Dienals for the Synthesis of Chiral Chromans

    DEFF Research Database (Denmark)

    Poulsen, Pernille H; Feu, Karla Santos; Paz, Bruno Matos;

    2015-01-01

    A novel asymmetric organocatalytic 1,6-addition/1,4-addition sequence to 2,4-dienals is described. Based on a 1,6-Friedel-Crafts/1,4-oxa-Michael cascade, the organocatalyst directs the reaction of hydroxyarenes with a vinylogous iminium-ion intermediate to give only one out of four possible regio...

  15. Palladium catalysed asymmetric alkylation of benzophenone Schiff base glycine esters in ionic liquids

    Indian Academy of Sciences (India)

    Dae Hyun Kim; Jin Kyu Im; Dae Won Kim; Minserk Cheong; Hoon Sik Kim; Deb Kumar Mukherjee

    2011-07-01

    Asymmetric alkyl substitution of various benzophenone Schiff base substrates under biphasic conditions proceeded using optically active Palladium(II) complexes. The corresponding products were obtained in high yields but with moderate enantiomeric excess (ee). Addition of specific ionic liquids to the reaction medium enhanced reactivity and selectivity for phase transfer catalytic (PTC) glycine alkylation. It has been found that there is an anionic influence of the ionic liquids that modify the steric environment around the enolate ion. A computer-assisted molecular design of enantioselective phase-transfer catalysis with the palladium complex and the ionic liquid has been done.

  16. Synthesis of Novel Chiral Dibenzo [ a, c ] cycloheptadiene Bis(oxazoline) and Catalytic Asymmetric Reactions

    Institute of Scientific and Technical Information of China (English)

    FU Bin; DU Da-Ming; WANG Jian-Bo

    2003-01-01

    @@ Over the last decade, C2-symmetric chiral oxazoline metal complexes have been recognized as an effective classof chiral catalyst in a variety of transition metal catalyzed asymmetric reactions. [1] High catalytic activities and enantiomeric excesses have been obtained using C2-symmetric chiral ligands in conjunction with suitable transition metal ion, for example, the hydrosilylation of ketone, allylic alkylation, Michael addition, Diels-Alder cycloaddition, and cyclopropanation. Thus, the design and synthesis of new chiral oxazoline ligands have inspired many scientists to work with great efforts.

  17. Influence of the lower-hybrid drift instability on magnetic reconnection in asymmetric configurations.

    Science.gov (United States)

    Roytershteyn, V; Daughton, W; Karimabadi, H; Mozer, F S

    2012-05-04

    Using fully kinetic 3D simulations of magnetic reconnection in asymmetric antiparallel configurations, we demonstrate that an electromagnetic lower-hybrid drift instability (LHDI) localized near the X line can substantially modify the reconnection mechanism in the regimes with large asymmetry, a moderate ratio of electron to ion temperature, and low plasma β. However, the mode saturates at a small amplitude in the regimes typical of Earth's magnetopause. In these cases, LHDI-driven turbulence is predominantly localized along the separatrices on the low-β side of the current sheet, in agreement with spacecraft observations.

  18. Internal Concentration Polarization in Asymmetric Membrane in Forward Osmosis System

    Science.gov (United States)

    Gadelha, Gabriela; Gadelha, Hermes; Hankins, Nick

    2013-11-01

    There has been a re-emerging interest in the study of the osmotic-driving desalination process known as Forward Osmosis (FO), due to its potential for significantly lower energy demand. However, the employed asymmetric semi-permeable membranes are notorious for the formation of unstirred boundary layers. These boundary layers may be dilutive or concentrative, causing an undesired decline on the osmotic flux. To date, although several models have been proposed in the literature to describe various applications in membrane separation processes, the fundamental theoretical basis has remained unchanged. Here, we detail an alternative formulation for the solute concentration profile and the water flux decline in terms of the osmotic Peclet number and the dimensionless solute permeability. Our analysis shows that the osmotic potential efficiency and the resulting water flux are inversely related, preventing any simultaneous optimization of the system, i.e. the larger the water flux is, the less osmotically efficient it becomes. We equally investigated the effect of distinct flat-sheet membrane configurations on the water flux. In this case, when the active layer faces the solution of low concentration (feed solution), under normal operations conditions, the water flux can be 60% lower than its counter configuration, when the active layer faces the solution of high concentration (draw solution). Finally, we contrast the theoretical formulation with experiments using inorganic ions and micelle as draw solutions.

  19. CONTRIBUTION FROM DEICING SALT TO CHEMICAL COMPOSITION OF SALT SUPPLYED TO AREA UNDER THE BRIDGES

    Science.gov (United States)

    Takebe, Masamichi; Ohya, Makoto; Hirose, Nozomu; Ochibe, Keishi; Aso, Toshihiko

    Salt is known to accelerate the corrosion of weathering steel bridges. The origin of salt around girders is valuable information in terms of the maintenance for anti-corrosion of steel bridges. Salt around girders generally originates from sea-salt and deicing salt. Since salt of both origin increases in winter, contribution of deicing salt is hard to be estimated only from fluctuation of total abundance of salt around the bridge. In this study, abundance of Mg2+ as well as that of Cl- in salt sampled under bridges is analyzed. As a result, this study revealed that the supply of deicing salt declines Mg2+/Cl- ratio of salt on the girder. In addition, examination of Mg2+/Cl- ratio of salt sampled under the examined bridge near sea revealed that the fluctuation of quantity of air-born salt under the bridge is ascribed to the fluctuation of supply of sea salt.

  20. Cerebral salt wasting syndrome

    Directory of Open Access Journals (Sweden)

    Harshal Dholke

    2016-01-01

    Full Text Available Traumatic brain injury (TBI is on the rise, especially in today′s fast-paced world. TBI requires not only neurosurgical expertise but also neurointensivist involvement for a better outcome. Disturbances of sodium balance are common in patients with brain injury, as the central nervous system plays a major role in sodium regulation. Hyponatraemia, defined as serum sodium <135 meq/L is commonly seen and is especially deleterious as it can contribute to cerebral oedema in these patients. Syndrome of inappropriate antidiuretic hormone secretion (SIADH, is the most well-known cause of hyponatraemia in this subset of patients. Cerebral Salt Wasting Syndrome (CSWS, leading to renal sodium loss is an important cause of hyponatraemia in patients with TBI. Although incompletely studied, decreased renal sympathetic responses and cerebral natriuretic factors play a role in the pathogenesis of CSWS. Maintaining a positive sodium balance and adequate hydration can help in the treatment. It is important to differentiate between SIADH and CSWS when trying to ascertain a case for patients with acute brain injury, as the treatment of the two are diametrically opposite.

  1. Young Stars with SALT

    CERN Document Server

    Riedel, Adric R; Rice, Emily L; Cruz, Kelle L; Henry, Todd J

    2016-01-01

    We present a spectroscopic and kinematic analysis of 79 nearby M dwarfs in 77 systems. All are low-proper-motion southern hemisphere objects and were identified in a nearby star survey with a demonstrated sensitivity to young stars. Using low-resolution optical spectroscopy from the Red Side Spectrograph (RSS) on the South African Large Telescope (SALT), we have determined radial velocities, H-alpha, Lithium 6708\\AA, and Potassium 7699\\AA~equivalent widths linked to age and activity, and spectral types for all our targets. Combined with astrometric information from literature sources, we identify 44 young stars. Eighteen are previously known members of moving groups within 100 parsecs of the Sun. Twelve are new members, including one member of the TW Hydra moving group, one member of the 32 Orionis moving group, nine members of Tucana-Horologium, one member of Argus, and two new members of AB Doradus. We also find fourteen young star systems that are not members of any known groups. The remaining 33 star syst...

  2. Rock salt constitutive modeling

    Energy Technology Data Exchange (ETDEWEB)

    Nickell, R.E.

    1980-03-18

    The Serata model is the best operational model available today because it incorporates: (1) a yield function to demarcate between viscoelastic and viscoplastic behavior of rock salt; (2) a pressure and temperature dependence for yield stresses; and (3) a standard linear solid, which can be readily extended into the non-linear regime, to represent creep behavior. Its only deficiencies appear to be the lack of secondary creep behavior (a free dashpot) and some unsettling arbitrariness about the Poisson's ratio (..nu.. ..-->.. 0.5) argument for viscoplasticity. The Sandia/WIPP model will have good primary and secondary creep capability, but lacks the viscoplastic behavior. In some cases, estimated inelastic strains may be underpredicted. If a creep acceleration mechanism associated with brine inclusions is observed, this model may require extensive revision. Most of the other models available (SAI, RE-SPEC, etc.) are only useful for short-term calculations, because they employ temporal power law (t/sup n/) primary creep representations. These models are unsatisfactory because they cannot represent dual mechanisms with differing characteristic times. An approach based upon combined creep and plasticity is recommended in order to remove the remaining deficiency in the Serata model. DOE/Sandia/WIPP should be encouraged to move aggressively in this regard.

  3. Salt intake, plasma sodium, and worldwide salt reduction.

    Science.gov (United States)

    He, Feng J; Macgregor, Graham A

    2012-06-01

    There is overwhelming evidence that a reduction in salt intake from the current level of approximately 9-12 g/d in most countries of the world to the recommended level of 5-6 g/d lowers blood pressure (BP) in both hypertensive and normotensive individuals. A further reduction to 3-4 g/d has a greater effect. Prospective studies and outcome trials have demonstrated that a lower salt intake is related to a reduced risk of cardiovascular disease. Cost-effectiveness analyses have documented that salt reduction is more or at the very least just as cost-effective as tobacco control in reducing cardiovascular disease, the leading cause of death and disability worldwide. The mechanisms whereby salt raises blood pressure and increases cardiovascular risk are not fully understood. The existing concepts focus on the tendency for an increase in extracellular fluid volume. Increasing evidence suggests that small increases in plasma sodium may have a direct effect on BP and the cardiovascular system, independent of extracellular volume. All countries should adopt a coherent and workable strategy to reduce salt intake in the whole population. Even a modest reduction in population salt intake will have major beneficial effects on health, along with major cost savings.

  4. Tetraploid citrus rootstocks are more tolerant to salt stress than diploid.

    Science.gov (United States)

    Saleh, Basel; Allario, Thierry; Dambier, Dominique; Ollitrault, Patrick; Morillon, Raphaël

    2008-09-01

    Citrus trees are subject to several abiotic constraints such as salinity. Providing new rootstocks more tolerant is thus a requirement. In this article, we investigated salt stress tolerance of three tetraploid rootstock genotypes when compared to their respective diploid rootstocks (Poncirus trifoliata, Carrizo citrange, Cleopatra mandarin). Plant growth, leaf fall and ion contents were investigated. At the end of the experiment, leaf fall was observed only for diploid Poncirus trifoliata plants as well as chlorosis symptoms for Poncirus trifoliata and Carrizo citrange diploid plants. The diploid Cleopatra mandarin plants growth rate was not affected by salt stress and has even been increased for tetraploid Cleopatra mandarin. Ion contents investigation has shown lower accumulations of chloride ions in leaves of the tetraploid plants when compared to diploid plants. Our results suggest that citrus tetraploid rootstocks are more tolerant to salt stress than their corresponding diploid.

  5. Hofmeister effect of salt mixtures on thermo-responsive poly(propylene oxide)

    DEFF Research Database (Denmark)

    Moghaddam, Saeed Zajforoushan; Thormann, Esben

    2015-01-01

    of aqueous solutions of poly(propylene oxide) is affected by mixtures of ions with different location in the Hofmeister series. Our results show that the Hofmeister effects of pure salt species are not always linearly additive and that the relative effect of some ions can be reversed depending......The Hofmeister series is a classification of ions regarding their ability to stabilize or destabilize aqueous solutions of proteins, polymers and other molecules which are partly miscible with water. In this study, we employ differential scanning calorimetry to investigate how the stability...... on the composition of the salt mixture as well as by the absolute and relative concentration of the different species. We suggest that these results can lead to a better understanding of the potential role of the Hofmeister effect in regulation of biological processes, which does always take place in salt mixtures...

  6. Asymmetric-Structure Analysis of Carbon and Energy Markets

    Science.gov (United States)

    Xu, Wei; Cao, Guangxi

    2016-02-01

    This study aimed to investigate the asymmetric structure between the carbon and energy markets from two aspects of different trends (up or down) and volatility-transmission direction using asymmetric detrended cross-correlation analysis (DCCA) cross-correlation coefficient test, multifractal asymmetric DCCA (MF-ADCCA) method, asymmetric volatility-constrained correlation metric and time rate of information-flow approach. We sampled 1283 observations from January 2008 to December 2012 among pairs of carbon and energy markets for analysis. Empirical results show that the (1) asymmetric characteristic from the cross-correlation between carbon and returns in the energy markets is significant, (2) asymmetric cross-correlation between carbon and energy market price returns is persistent and multifractral and (3) volatility of the base assets of energy market returns is more influential to the base asset of the carbon market than that of the energy market.

  7. Quantum optics of lossy asymmetric beam splitters

    Science.gov (United States)

    Uppu, Ravitej; Wolterink, Tom A. W.; Tentrup, Tristan B. H.; Pinkse, Pepijn W. H.

    2016-07-01

    We theoretically investigate quantum interference of two single photons at a lossy asymmetric beam splitter, the most general passive 2$\\times$2 optical circuit. The losses in the circuit result in a non-unitary scattering matrix with a non-trivial set of constraints on the elements of the scattering matrix. Our analysis using the noise operator formalism shows that the loss allows tunability of quantum interference to an extent not possible with a lossless beam splitter. Our theoretical studies support the experimental demonstrations of programmable quantum interference in highly multimodal systems such as opaque scattering media and multimode fibers.

  8. Improved DFIG Capability during Asymmetrical Grid Faults

    DEFF Research Database (Denmark)

    Zhou, Dao; Blaabjerg, Frede

    2015-01-01

    the natural component of the Doubly-Fed Induction Generator (DFIG) stator flux during the fault period, their effects on the rotor voltage can be investigated. It is concluded that the phase-to-phase fault has the worst scenario due to its highest introduction of the negative stator flux. Afterwards......, the capability of a 2 MW DFIG to ride through asymmetrical grid faults can be estimated at the existing design of the power electronics converter. Finally, a control scheme aimed to improve the DFIG capability is proposed and the simulation results validate its feasibility....

  9. Resonance phenomena for asymmetric weakly nonlinear oscillator

    Institute of Scientific and Technical Information of China (English)

    钱定边

    2002-01-01

    We establish the coexistence of periodic solution and unbounded solution, the infinity of largeamplitude subharmonics for asymmetric weakly nonlinear oscillator x" + a2x+ - b2x- + h(x) = p(t) with h(±∞) - 0 and xh(x) → +∞(x →∞), assuming that M(τ ) has zeros which are all simple and M(τ ) 0respectively, where M(τ ) is a function related to the piecewise linear equation x" + a2x+ - b2x- = p(t).``

  10. Dynamic Conditional Correlations for Asymmetric Processes

    OpenAIRE

    Asai, Manabu; McAleer, Michael

    2011-01-01

    The paper develops two Dynamic Conditional Correlation (DCC) models, namely the Wishart DCC (wDCC) model. The paper applies the wDCC approach to the exponential GARCH (EGARCH) and GJR models to propose asymmetric DCC models. We use the standardized multivariate t-distribution to accommodate heavy-tailed errors. The paper presents an empirical example using the trivariate data of the Nikkei 225, Hang Seng and Straits Times Indices for estimating and forecasting the wDCC-EGARCH and wDCC-GJR mod...

  11. On asymmetric causal relationships in Petropolitics

    Directory of Open Access Journals (Sweden)

    Balan Feyza

    2016-01-01

    Full Text Available The aim of this paper is to examine whether the First Law of Petropolitics denominated by Friedman in 2006 is valid for OPEC countries. To do this, this paper analyses the relationship between political risk and oil supply by applying the asymmetric panel causality test suggested by Hatemi-J (2011 to these countries for the period 1984-2014. The results show that the First Law of Petropolitics is valid for Angola, Iraq, Kuwait, Libya, Nigeria, Qatar, Saudi Arabia, and the UAE, given that positive oil supply shocks significantly lead to negative political stability shocks, and negative oil supply shocks significantly lead to positive shocks in political stability.

  12. Quantum optics of lossy asymmetric beam splitters

    CERN Document Server

    Uppu, Ravitej; Tentrup, Tristan B H; Pinkse, Pepijn W H

    2016-01-01

    We theoretically investigate quantum interference of two single photons at a lossy asymmetric beam splitter, the most general passive 2$\\times$2 optical circuit. The losses in the circuit result in a non-unitary scattering matrix with a non-trivial set of constraints on the elements of the scattering matrix. Our analysis using the noise operator formalism shows that the loss allows tunability of quantum interference to an extent not possible with a lossless beam splitter. Our theoretical studies support the experimental demonstrations of programmable quantum interference in highly multimodal systems such as opaque scattering media and multimode fibers.

  13. Asymmetric chemical reactions by polarized quantum beams

    Science.gov (United States)

    Takahashi, Jun-Ichi; Kobayashi, Kensei

    One of the most attractive hypothesis for the origin of homochirality in terrestrial bio-organic compounds (L-amino acid and D-sugar dominant) is nominated as "Cosmic Scenario"; a chiral impulse from asymmetric excitation sources in space triggered asymmetric reactions on the surfaces of such space materials as meteorites or interstellar dusts prior to the existence of terrestrial life. 1) Effective asymmetric excitation sources in space are proposed as polarized quantum beams, such as circularly polarized light and spin polarized electrons. Circularly polarized light is emitted as synchrotron radiation from tightly captured electrons by intense magnetic field around neutron stars. In this case, either left-or right-handed polarized light can be observed depending on the direction of observation. On the other hand, spin polarized electrons is emitted as beta-ray in beta decay from radioactive nuclei or neutron fireballs in supernova explosion. 2) The spin of beta-ray electrons is longitudinally polarized due to parity non-conservation in the weak interaction. The helicity (the the projection of the spin onto the direction of kinetic momentum) of beta-ray electrons is universally negative (left-handed). For the purpose of verifying the asymmetric structure emergence in bio-organic compounds by polarized quantum beams, we are now carrying out laboratory simulations using circularly polarized light from synchrotron radiation facility or spin polarized electron beam from beta-ray radiation source. 3,4) The target samples are solid film or aqueous solution of racemic amino acids. 1) K.Kobayashi, K.Kaneko, J.Takahashi, Y.Takano, in Astrobiology: from simple molecules to primitive life; Ed. V.Basiuk; American Scientific Publisher: Valencia, 2008. 2) G.A.Gusev, T.Saito, V.A.Tsarev, A.V.Uryson, Origins Life Evol. Biosphere. 37, 259 (2007). 3) J.Takahashi, H.Shinojima, M.Seyama, Y.Ueno, T.Kaneko, K.Kobayashi, H.Mita, M.Adachi, M.Hosaka, M.Katoh, Int. J. Mol. Sci. 10, 3044

  14. Photoresponse of silicon with asymmetric area contacts

    Science.gov (United States)

    Rabbani, M. Golam; Sundararajan, Jency P.; Verma, Amit; Nekovei, Reza; Khader, Mahmoud M.; Darling, R. B.; Patil, Sunil R.

    2017-01-01

    We report on high performance metal-semiconductor-metal (MSM) photosensors based on asymmetric metal pad areas. The reported devices require a single-step metal deposition, and exhibit large photo response even under zero-bias. Moreover the devices offer fast and stable light switching behavior. Device fabrication and electrical characterization results are presented that are further analyzed with TCAD modeling and simulation. Device simulations show that contact asymmetry along with surface recombination and barrier lowering plays an important role in the MSM I-V characteristics.

  15. Chiral Diamine-catalyzed Asymmetric Aldol Reaction

    Institute of Scientific and Technical Information of China (English)

    LI Hui; XU Da-zhen; WU Lu-lu; WANG Yong-mei

    2012-01-01

    A highly efficient catalytic system composed of a simple and commercially available chiral primary diamine (1R,2R)-cyclohexane-1,2-diamine(6) and trifluoroacetic acid(TFA) was employed for asymmetric Aldol reaction in i-PrOH at room temperature.A loading of 10%(molar fraction) catalyst 6 with TFA as a cocatalyst could catalyze the Aldol reactions of various ketones or aldehydes with a series of aromatic aldehydes,furnishing Aldol products in moderate to high yields(up to >99%) with enantioselectivities of up to >99% and diastereoselectivities of up to 99:1.

  16. Analysis of Asymmetric Piezoelectric Composite Beam

    CERN Document Server

    Chen, J -S; Wu, K -C

    2008-01-01

    This paper deals with the vibration analysis of an asymmetric composite beam composed of glass a piezoelectric material. The Bernoulli's beam theory is adopted for mechanical deformations, and the electric potential field of the piezoelectric material is assumed such that the divergence-free requirement of the electrical displacements is satisfied. The accuracy of the analytic model is assessed by comparing the resonance frequencies obtained by the analytic model with those obtained by the finite element method. The model developed can be used as a tool for designing piezoelectric actuators such as micro-pumps.

  17. Asymmetric Synthesis of Both Enantiomers of Disparlure

    Institute of Scientific and Technical Information of China (English)

    王志刚; 郑剑峰; 黄培强

    2012-01-01

    Starting from propargyl alcohol (12), and on the basis of Zhou's modified Sharpless asymmetric epoxidation, the sex pheromone of the Gypsy moth, disparlure (+)-8 and its enantiomer (-)-8 have been synthesized, each in six steps, with overall yields of 29% for (+)-8 and 27% for (-)-8 (ee〉98%). The use of the sequential coupling tactic renders the method flexible, which is applicable to the synthesis of other cis-epoxy pheromones.

  18. Nanotribology of Symmetric and Asymmetric Liquid Lubricants

    Directory of Open Access Journals (Sweden)

    Shinji Yamada

    2010-03-01

    Full Text Available When liquid molecules are confined in a narrow gap between smooth surfaces, their dynamic properties are completely different from those of the bulk. The molecular motions are highly restricted and the system exhibits solid-like responses when sheared slowly. This solidification behavior is very dependent on the molecular geometry (shape of liquids because the solidification is induced by the packing of molecules into ordered structures in confinement. This paper reviews the measurements of confined structures and friction of symmetric and asymmetric liquid lubricants using the surface forces apparatus. The results show subtle and complex friction mechanisms at the molecular scale.

  19. Neuronal Alignment On Asymmetric Textured Surfaces

    CERN Document Server

    Beighley, Ross; Sekeroglu, Koray; Atherton, Timothy; Demirel, Melik C; Staii, Cristian

    2013-01-01

    Axonal growth and the formation of synaptic connections are key steps in the development of the nervous system. Here we present experimental and theoretical results on axonal growth and interconnectivity in order to elucidate some of the basic rules that neuronal cells use for functional connections with one another. We demonstrate that a unidirectional nanotextured surface can bias axonal growth. We perform a systematic investigation of neuronal processes on asymmetric surfaces and quantify the role that biomechanical surface cues play in neuronal growth. These results represent an important step towards engineering directed axonal growth for neuro-regeneration studies.

  20. Asymmetric acoustic transmission in graded beam

    Science.gov (United States)

    Jing, Li; Wu, Jiu Hui; Guan, Dong; Lu, Kuan; Gao, Nansha; Songhua, Cao

    2016-12-01

    We demonstrate the dynamic effective material parameters and vibration performance of a graded beam. The structure of the beam was composed of several unit cells with different fill factors. The dispersion relations and energy band structures of each unit cell were calculated using the finite element method (FEM). The dynamic effective material parameters in each unit cell of the graded beam were determined by the dispersion relations and energy band structures. Longitudinal wave propagation was investigated using a numerical method and FEM. The results show that the graded beam allows asymmetric acoustic transmission over a wide range of frequencies.

  1. Ion specific effects on charged interfaces

    OpenAIRE

    Medda, Luca

    2013-01-01

    The physico-chemical phenomena occurring at charged interfaces are specifically affected by the type and the concentration of electrolytes. This has implications both in living and in inorganic systems. The discovery of the ‘ion specific effects’ dates back to Hofmeister (1888), who observed the specific effect of salts in promoting egg white proteins precipitation. Nowadays we are aware that ion specific effects are ubiquitous in all fields of science and technology where electrolytes play a...

  2. An Asymmetric Block Dynamic Conditional Correlation Multivariate GARCH Model

    OpenAIRE

    Vargas, Gregorio A.

    2006-01-01

    The Block DCC model for determining dynamic correlations within and between groups of financial asset returns is extended to account for asymmetric effects. Simulation results show that the Asymmetric Block DCC model is competitive in in-sample forecasting and performs better than alternative DCC models in out-of-sample forecasting of conditional correlation in the presence of asymmetric effect between blocks of asset returns. Empirical results demonstrate that the model is able to capture ...

  3. Asymmetric joint multifractal analysis in Chinese stock markets

    Science.gov (United States)

    Chen, Yuwen; Zheng, Tingting

    2017-04-01

    In this paper, the asymmetric joint multifractal analysis method based on statistical physics is proposed to explore the asymmetric correlation between daily returns and trading volumes in Chinese stock markets. The result shows asymmetric multifractal correlations exist between return and trading volume in Chinese stock markets. Moreover, when the stock indexes are upward, the fluctuations of returns are always weaker than when they are downward, whether the trading volumes are more or less.

  4. Asymmetric Campaigning as a Rational Choice: Planning Considerations

    Science.gov (United States)

    2006-06-01

    Maslow identified five levels: survival, safety, belonging, esteem, and self-actualization. He presented his theory as a pyramid with five layers...to be sustained by actions of the asymmetric opponent. For the media-fed frenzy over constraints and protraction to continue, the asymmetric...lot of people. The reason for this is twofold. First, the actor needs sufficient support to exist and to sustain an asymmetric campaign. Second, the

  5. Calcium supplementation improves Na+/K+ ratio, antioxidant defense and glyoxalase systems in salt-stressed rice seedlings

    Directory of Open Access Journals (Sweden)

    Anisur eRahman

    2016-05-01

    Full Text Available The present study investigates the regulatory role of exogenous calcium (Ca in developing salt stress tolerance in rice seedlings. Hydroponically grown 13-d-old rice (Oryza sativa L. cv. BRRI dhan47 seedlings were exposed to 200 mM NaCl alone and combined with 2 mM CaCl2 and 2 mM ethylene glycol tetraacetic acid (EGTA, a Ca scavenger for three days. The salt stress caused growth inhibition, chlorosis and water shortage in the rice seedlings. The salt-induced stress disrupted ion homeostasis through Na+ influx and K+ efflux, and decreased other mineral nutrient uptake. Salt-induced stress caused oxidative stress in rice seedlings through lipid peroxidation, loss of plasma membrane integrity, higher reactive oxygen species (ROS production and methylglyoxal (MG formation. The salt-stressed rice seedlings supplemented with exogenous Ca recovered from water loss, chlorosis and growth inhibition. Calcium supplementation in the salt-stressed rice seedlings improved ion homeostasis by inhibition of Na+ influx and K+ leakage. Exogenous Ca also improved ROS and MG detoxification by improving the antioxidant defense and glyoxalase systems, respectively. On the other hand, applying EGTA along with salt and Ca again negatively affected the rice seedlings as EGTA negated Ca activity. It confirms that, the positive responses in salt-stressed rice seedlings to exogenous Ca were for Ca mediated improvement of ion homeostasis, antioxidant defense and glyoxalase system.

  6. Calcium Supplementation Improves Na+/K+ Ratio, Antioxidant Defense and Glyoxalase Systems in Salt-Stressed Rice Seedlings

    Science.gov (United States)

    Rahman, Anisur; Nahar, Kamrun; Hasanuzzaman, Mirza; Fujita, Masayuki

    2016-01-01

    The present study investigates the regulatory role of exogenous calcium (Ca) in developing salt stress tolerance in rice seedlings. Hydroponically grown 13-day-old rice (Oryza sativa L. cv. BRRI dhan47) seedlings were exposed to 200 mM NaCl alone and combined with 2 mM CaCl2 and 2 mM ethylene glycol tetraacetic acid (EGTA, a Ca scavenger) for 3 days. The salt stress caused growth inhibition, chlorosis and water shortage in the rice seedlings. The salt-induced stress disrupted ion homeostasis through Na+ influx and K+ efflux, and decreased other mineral nutrient uptake. Salt stress caused oxidative stress in seedlings through lipid peroxidation, loss of plasma membrane integrity, higher reactive oxygen species (ROS) production and methylglyoxal (MG) formation. The salt-stressed seedlings supplemented with exogenous Ca recovered from water loss, chlorosis and growth inhibition. Calcium supplementation in the salt-stressed rice seedlings improved ion homeostasis by inhibition of Na+ influx and K+ leakage. Exogenous Ca also improved ROS and MG detoxification by improving the antioxidant defense and glyoxalase systems, respectively. On the other hand, applying EGTA along with salt and Ca again negatively affected the seedlings as EGTA negated Ca activity. It confirms that, the positive responses in salt-stressed rice seedlings to exogenous Ca were for Ca mediated improvement of ion homeostasis, antioxidant defense and glyoxalase system. PMID:27242816

  7. Microbial desalination cell with capacitive adsorption for ion migration control.

    Science.gov (United States)

    Forrestal, Casey; Xu, Pei; Jenkins, Peter E; Ren, Zhiyong

    2012-09-01

    A new microbial desalination cell with capacitive adsorption capability (cMDC) was developed to solve the ion migration problem facing current MDC systems. Traditional MDCs remove salts by transferring ions to the anode and cathode chambers, which may prohibit wastewater beneficial reuse due to increased salinity. The cMDC uses adsorptive activated carbon cloth (ACC) as the electrodes and utilizes the formed capacitive double layers for electrochemical ion adsorption. The cMDC removed an average of 69.4% of the salt from the desalination chamber through electrode adsorption during one batch cycle, and it did not add salts to the anode or cathode chamber. It was estimated that 61-82.2mg of total dissolved solids (TDS) was adsorbed to 1g of ACC electrode. The cMDC provides a new approach for salt management, organic removal, and energy production. Further studies will be conducted to optimize reactor configuration and achieve in situ electrode regeneration.

  8. Asymmetric transmission: a generic property of lossy periodic interfaces

    CERN Document Server

    Plum, E; Zheludev, N I

    2010-01-01

    Asymmetric transmission of circularly polarized waves is a well-established property of lossy, anisotropic, two-dimensionally chiral patterns. Here we show that asymmetric transmission can be observed for oblique incidence onto any lossy periodically structured plane. Our results greatly expand the range of natural and artificial materials in which directionally asymmetric transmission can be expected making it a cornerstone electromagnetic effect rather than a curiosity of planar chiral metamaterials. Prime candidates for asymmetric transmission at oblique incidence are rectangular arrays of plasmonic spheres or semiconductor quantum dots, lossy double-periodic gratings and planar metamaterial structures.

  9. Quantity Discount Scheme in Supply Chain under Asymmetric Information

    Institute of Scientific and Technical Information of China (English)

    LI Ji-bin; PENG Zuo-he

    2007-01-01

    Quantity discount scheme plays an important role in supply chain management. The different quantity discount schemes under symmetric (full) information and asymmetric information, are analyzed by using principal-agent and optimal control theory. As a result, the research reveals that the optimal quantity discount solution under symmetric information is a special case of that under asymmetric information. At the same price, the critical value of quantity discount under asymmetric information is much lower than that under asymmetric information. Therefore, this leads to less cost for retailers and smaller profit for their supplier.

  10. Microbiology of solar salt ponds

    Science.gov (United States)

    Javor, B.

    1985-01-01

    Solar salt ponds are shallow ponds of brines that range in salinity from that of normal seawater (3.4 percent) through NaCl saturation. Some salterns evaporate brines to the potash stage of concentration (bitterns). All the brines (except the bitterns, which are devoid of life) harbor high concentrations of microorganisms. The high concentrations of microorganisms and their adaptation to life in the salt pond are discussed.

  11. Processes of Salt Transport in Disturbed Streams

    Science.gov (United States)

    Chitrakar, S.; Miller, S. N.; Caffrey, P. A.; Stern, J.

    2013-12-01

    The extraction of coal bed methane natural gas involves removal of large amount of ground/Coal Bed Methane (CBM) water which is commonly discharged to surface-water drainages or constructed reservoirs. The extraction of large volume of water and its disposal on soil surface not only lowers the water table but also potentially accelerate soil erosions, contaminate surface water resources, and alter the natural flows. Due to the difference in quality and quantity between the surface discharge and disposed CBM water, this management strategy potentially poses threats to quality of surface water and soil. CBM discharge water typically contains high concentrations of sodium and low concentrations of calcium and magnesium, resulting in high sodium adsorption ratio (SAR). Similarly, it also contains high concentration of other ions which could results in increasing salt concentrations. Our study area is in the Atlantic Rim development area of the Muddy Creek, SE of Wyoming, a tributary to Colorado River, where significant development of CBM wells is ongoing. Since Muddy Creek is part of the Upper Colorado River, the greatest concern is its potential to contribute to surface water quality (primarily salinity) impairment downstream. However, very few studies have made efforts to assess the water quality in this particular region. The alteration of stream water quality in this region is still not fully understood if it due to CBM water discharge or via soil/water interactions, erosion, and sediment transport. Efforts are being made to identify crucial water quality parameters such as SAR and EC along with the quantification of solute/salt loadings at both CBM discharge fed streams and natural streams at different seasons to distinguish effect of CBM discharge on water quality. We have been continuously monitoring water quality on monthly basis and discharge measurement on daily basis at sampling sites that are placed to discriminate CBM fed streams and natural streams. The

  12. Scheme for on-resonance generation of entanglement in time-dependent asymmetric two-qubit-cavity systems

    Science.gov (United States)

    Olaya-Castro, Alexandra; Johnson, Neil F.; Quiroga, Luis

    2004-08-01

    We present an efficient scheme for the controlled generation of pure two-qubit states possessing any desired degree of entanglement and a prescribed symmetry. This is achieved in two-qubit-cavity QED systems (e.g., cold-trapped ions and flying atoms) via on-resonance ion- or atom-cavity couplings, which are time dependent and asymmetric, yielding a trapping vacuum state condition which does not arise for identical couplings. A duality in the role of the coupling ratio yields states with a given concurrence but opposing symmetries. Both the trapping state condition and the resulting entanglement power are robust against decoherence channels.

  13. Cerebral Salt Wasting Syndrome

    Directory of Open Access Journals (Sweden)

    Mehmet Salih Sevdi

    2016-12-01

    Full Text Available A serum sodium (Na value below 135 mEq/L is evaluated as hyponatremia. Hyponatremia is the most common electrolyte abnormality observed in hospitalized patients in particular. Hypovolemic hypoosmolar hyponatremia is the most frequent clinical table. One of the reasons of this is cerebral salt-wasting syndrome (CSWS. CSWS is a rare condition progressing with low plasma osmolality, urine osmolality above 100-150 mOsm/kg and urine- Na concentration above 20 mEq/L. In the blood and urine sample analysis performed upon sudden loss of consciousness on the 15th day of the intensive care unit follow-up of 79-year-old female patients due to falling from stairs, blood biochemistry Na value was 120 mEq/L, plasma osmolality was 250 mOsm/kg, urine Na value was 180 mEq/L, urine osmolality was 1200 mOsm/kg, urine diuresis was >3 mL/kg/hour. The central venous pressure was 2 mmHg. The patient, considered to be diagnosed with CSWS, was treated with 9% NaCl and 3% hypertonic saline solution. Her clinical course was improved on the 18th day. She died on the 81st day secondary to septicemia in the subsequent follow-up. In this article, it was aimed to report a patient with CSWS which progresses with low percentage in intensive care unit patients with head trauma, is frequently confused with inappropriate antidiuretic hormone syndrome and progresses mortally when not diagnosed distinctively well.

  14. Liking, salt taste perception and use of table salt when consuming reduced-salt chicken stews in light of South Africa's new salt regulations.

    Science.gov (United States)

    De Kock, H L; Zandstra, E H; Sayed, N; Wentzel-Viljoen, E

    2016-01-01

    This study investigated the impact of salt reduction on liking, salt taste perception, and use of table salt when consuming chicken stew in light of South Africa's new salt recommendations. In total, 432 South-African consumers (aged 35.2 ± 12.3 years) consumed a full portion of a chicken stew meal once at a central location. Four stock cube powders varying in salt content were used to prepare chicken stews: 1) no reduction - 2013 Na level; regular salt level as currently available on the South African market (24473 mg Na/100 g), 2) salt reduction smaller than 2016 level, i.e. 10%-reduced (22025 mg Na/100 g), 3) 2016 salt level, as per regulatory prescriptions (18000 mg Na/100 g), 4) 2019 salt level, as per regulatory prescriptions (13000 mg Na/100 g). Consumers were randomly allocated to consume one of the four meals. Liking, salt taste perception, and use of table salt and pepper were measured. Chicken stews prepared with reduced-salt stock powders were equally well-liked as chicken stews with the current salt level. Moreover, a gradual reduction of the salt in the chicken stews resulted in a reduced salt intake, up to an average of 19% for the total group compared to the benchmark 2013 Na level stew. However, 19% of consumers compensated by adding salt back to full compensation in some cases. More salt was added with increased reductions of salt in the meals, even to the point of full compensation. Further investigation into the impacts of nutrition communication and education about salt reduction on salt taste perception and use is needed. This research provides new consumer insights on salt use and emphasises the need for consumer-focused behaviour change approaches, in addition to reformulation of products.

  15. A closer look at salt loaded microstructures

    NARCIS (Netherlands)

    Rooij, M.R. de

    2006-01-01

    Many walls of ancient buildings are covered with plaster layers. Amongst the most recurrent causes of damage of plasters and substrates are moisture and salt decay processes. To combat these salt problems, special salt resistant plasters have been developed for application on salt loaded substrates.

  16. Asymmetric disassembly and robustness in declining networks.

    Science.gov (United States)

    Saavedra, Serguei; Reed-Tsochas, Felix; Uzzi, Brian

    2008-10-28

    Mechanisms that enable declining networks to avert structural collapse and performance degradation are not well understood. This knowledge gap reflects a shortage of data on declining networks and an emphasis on models of network growth. Analyzing >700,000 transactions between firms in the New York garment industry over 19 years, we tracked this network's decline and measured how its topology and global performance evolved. We find that favoring asymmetric (disassortative) links is key to preserving the topology and functionality of the declining network. Based on our findings, we tested a model of network decline that combines an asymmetric disassembly process for contraction with a preferential attachment process for regrowth. Our simulation results indicate that the model can explain robustness under decline even if the total population of nodes contracts by more than an order of magnitude, in line with our observations for the empirical network. These findings suggest that disassembly mechanisms are not simply assembly mechanisms in reverse and that our model is relevant to understanding the process of decline and collapse in a broad range of biological, technological, and financial networks.

  17. Algebraic Davis Decomposition and Asymmetric Doob Inequalities

    Science.gov (United States)

    Hong, Guixiang; Junge, Marius; Parcet, Javier

    2016-09-01

    In this paper we investigate asymmetric forms of Doob maximal inequality. The asymmetry is imposed by noncommutativity. Let {({M}, τ)} be a noncommutative probability space equipped with a filtration of von Neumann subalgebras {({M}_n)_{n ≥ 1}}, whose union {bigcup_{n≥1}{M}_n} is weak-* dense in {{M}}. Let {{E}_n} denote the corresponding family of conditional expectations. As an illustration for an asymmetric result, we prove that for {1 spaces {{H}_p^r({M})} and {{H}_p^c({M})} respectively. In particular, this solves a problem posed by the Defant and Junge in 2004. In the case p = 1, our results establish a noncommutative form of the Davis celebrated theorem on the relation betwe en martingale maximal and square functions in L 1, whose noncommutative form has remained open for quite some time. Given {1 ≤ p ≤ 2}, we also provide new weak type maximal estimates, which imply in turn left/right almost uniform convergence of {{E}_n(x)} in row/column Hardy spaces. This improves the bilateral convergence known so far. Our approach is based on new forms of Davis martingale decomposition which are of independent interest, and an algebraic atomic description for the involved Hardy spaces. The latter results are new even for commutative von Neumann algebras.

  18. Asymmetric DSL Technology of Signal Transmission

    Directory of Open Access Journals (Sweden)

    Dražen Kovačević

    2005-05-01

    Full Text Available Asymmetric flow of information is the key feature of theADSL (Asymmetric Digital Subscriber Loop technology, i.e.higher data transmission rate towards the user than from theuser towards the network. Characteristic is the short messagesending by the user with a certain request to the se!Ver. These!Ver responds to the request by a significantly longer messageof various electronic forms (data, digitized speech, pictures orvideo. Therefore, this technology is most often used by smalland medium users. ADSL is currently the only commerciallyavailable DSL technology which is still experiencing the breakthroughon the seiVice market. It enables faster access to theInternet, LAN (Local Area Network, videoconferencing, VoD(Video on Demand and interactive multimedia. In order tostandardize such se/Vices, the !TU (International TelecommunicationsUnion G. 992.1 (standardized DMT-discrete multi-tone line coding technology and ANSJ (American NationalStandards Institution Tl.413-95!98 are used for ADSL. DMT(Discrete Multi Tone, as the more popular one, uses the linecoding technique, which splits a certain frequency range intoseveral sub-channels. Most of these sub-channels are used forupstream and downstream transmission of speech and data,whereas some are used as pilot signals or kept in rese/Ve. Suchmodulation technique expands the frequency spectrum, allowingthe usage ofbroadband se/Vices per one pair of wires. In thisway the sharing of speech and data se/Vice transmission is realized.

  19. An asymmetric B factory based on PEP

    Energy Technology Data Exchange (ETDEWEB)

    1991-02-01

    In this report we describe a design for a high-luminosity Asymmetric B Factory to be built in the PEP tunnel on the SLAC site. This proposal, a collaborative effort SLAC, LBL, and LLNL, is the culmination of more than two years of effort aimed at the design and construction of an asymmetric e{sup +}e{sup {minus}} collider capable of achieving a luminosity of L = 3 {times} 10{sup 33} cm{sup {minus}2} s{sup {minus}1}. The configuration adopted utilizes two storage rings, and electron ring operating at 9 GeV and a positron ring at 3.1 GeV, each with a circumference of 2200 m. The high-energy ring is an upgrade of the PEP storage ring at SLAC; all PEP magnets and most power supplies will be reused. The upgrade consists primarily of replacing the PEP vacuum chamber and RF system with newly designed versions optimized for the high-current environment of the B Factory. The low-energy ring will be newly constructed and will be situated atop the high-energy ring in the PEP tunnel. Utilities already installed in the PEP tunnel are largely sufficient to operate the two B Factory storage rings.

  20. Evolutionary stability in the asymmetric volunteer's dilemma.

    Directory of Open Access Journals (Sweden)

    Jun-Zhou He

    Full Text Available It is often assumed that in public goods games, contributors are either strong or weak players and each individual has an equal probability of exhibiting cooperation. It is difficult to explain why the public good is produced by strong individuals in some cooperation systems, and by weak individuals in others. Viewing the asymmetric volunteer's dilemma game as an evolutionary game, we find that whether the strong or the weak players produce the public good depends on the initial condition (i.e., phenotype or initial strategy of individuals. These different evolutionarily stable strategies (ESS associated with different initial conditions, can be interpreted as the production modes of public goods of different cooperation systems. A further analysis revealed that the strong player adopts a pure strategy but mixed strategies for the weak players to produce the public good, and that the probability of volunteering by weak players decreases with increasing group size or decreasing cost-benefit ratio. Our model shows that the defection probability of a "strong" player is greater than the "weak" players in the model of Diekmann (1993. This contradicts Selten's (1980 model that public goods can only be produced by a strong player, is not an evolutionarily stable strategy, and will therefore disappear over evolutionary time. Our public good model with ESS has thus extended previous interpretations that the public good can only be produced by strong players in an asymmetric game.